Top Industrial Belt Conveyor Issues

    Top Industrial Belt Conveyor Issues


    The advent of troughed belt conveyors fundamentally changed industrial processing, increasing efficiencies, reducing labor requirements, improving safety, and streamlining production. These flexible devices have become the standard for moving product and material around a facility and are found in every industry imaginable.


   



    While belt conveyors provide a reliable, efficient bulk handling solution, they can experience occasional problems. And when issues arise, they can wreak havoc on a production line. Below are some of the most commonly seen issues when working with belt conveyors, including what causes these problems and how to prevent them.


   



    Note: This is not a comprehensive list and does not substitute for the expertise of a professional. Always consult your original equipment manufacturer or manual to ensure all necessary safety, maintenance, and troubleshooting guidelines are followed. Maintenance and storage procedures should always be carried out by a trained professional. FEECO does not make any representations or warranties (implied or otherwise) regarding the accuracy and completeness of this guide and shall in no event be liable for any loss of profit or any commercial damage, including but not limited to special, incidental, consequential, or other damage.


    Carryback is the material that remains on the belt after discharge and is perhaps the most common struggle among conveyor pulley. Typically all conveyors experience carryback to some extent, but given its potential for serious consequences, keeping it to a minimum is essential.


   



    WHY CARRYBACK IS AN ISSUE


    Carryback creates a messy and potentially hazardous work environment, as it gets into the undercarriage and surrounding area of the conveyor. This can cause outages and increase the time devoted to cleaning and maintenance.


   



    Not only does carryback create a mess, but material allowed to build up on rollers, idlers, and pulleys degrades these components, causing excessive wear. Further, a buildup of carryback can also cause belt tracking issues, potentially wearing and damaging the belt.


   



    WHAT CAUSES CARRYBACK


    Carryback is largely a result of the conveyed material’s characteristics and propensity for sticking. In general, a material with a higher moisture content is more likely to stick to the belt. Similarly, carryback can be more of a problem in humid environments where hygroscopic materials pull moisture from the air, increasing the likelihood of sticking.


   



    Sticking can also occur when condensation is produced as a result of extreme temperature differences between the material and the belt.


   



    HOW TO PREVENT CARRYBACK


    The best way to prevent carryback is to utilize one or more belt cleaners. Belt cleaners can be installed at both the head and tail pulley and serve to ride against the conveyor belt, dislodging any material that may be adhered to the belt. These devices substantially reduce buildup on the belt, and depending on the level of carryback, several options may be appropriate. Common options include a self-cleaning tail pulley, return side belt plow (v-plow), and dual belt cleaners.


   



    Routine cleaning should also be prioritized as part of a conveyor head pulley maintenance program in order to minimize any remaining buildup on components.


   



    CONVEYOR BELT MISTRACKING


    Tracking, or training, refers to the way in which the belt rides on the rollers. Conveyor belts should always track centrally. Mistracking occurs when the conveyor rubber belt rides unevenly on rollers, favoring one side over the other.


    Like carryback, mistracking can cause several issues in a conveyor system. This includes uneven belt wear, belt damage resulting from catching or rubbing on surrounding infrastructure, material spillage, warped belting or belts that are not square, and more.


   



    Mistracking is also recognized as a safety violation by the US Department of Labor’s Mine Safety and Health Administration (MSHA). When a belt is not tracking properly, areas that are normally safe can become pinch points, presenting a hazard to workers. Mistracking can also cause material to fall off of the conveyor, falling on to workers and equipment, or creating piles that present a safety risk.


   



    WHAT CAUSES MISTRACKING


    Since conveyor bend pulley are carefully balanced, any number of factors may be the source of mistracking, making it difficult to identify the origin of the problem. Potential causes of mistracking include improper idler spacing, seized or worn rollers, a misaligned frame, material buildup on any part of the conveyor, excessive belt tensioning, and a worn or damaged belt, to name a few.


   



    HOW TO PREVENT MISTRACKING


    The range of possible mistracking causes make a blanket solution to prevention impossible. There are, however, measures that can help to reduce the potential for this issue to occur.


   



    Conveyors can fall out of perfect alignment through normal wear and tear. As a result, routinely inspecting alignment of the conveyor structure and its many components helps to prevent mistracking. Off-center loading can also create an alignment issue, so ensure that chutes are positioned centrally over loading areas.


   



    Since mistracking can be caused by material buildup, it’s also important to keep the belt conveyor, idlers, and pulleys clean. This will reduce wear on components, which could also cause mistracking.


   



    Slight off-tracking issues can be remedied by “knocking idlers,” a practice in which idlers are skewed a small amount to correct an off-tracking belt.


   



    SLIPPAGE


    Belt slippage typically occurs around the drive/head pulley and happens when the belt and pulley do not have enough grip to adequately turn the belt around the pulley.


   



    WHY BELT SLIPPING IS AN ISSUE


    Belt slipping reduces productivity and efficiency, causing process upsets, or preventing the proper amount of material from being conveyed. It can also cause belt wear and damage, and put added stress on the motor, resulting in premature failure.


   



    WHAT CAUSES SLIPPAGE


    There are several reasons why a belt experiences slipping. This includes:


   



    Low temperatures (cold temperatures can reduce the amount of grip between the pulley and belt)


    Improperly installed pulley lagging


    Buildup on pulley


    Inadequate belt tension


    Worn head pulley


    Smooth pulley surface


    Load that is too heavy for conveyor


    HOW TO PREVENT SLIPPAGE


    There are several ways to prevent slippage. Maintaining an adequate belt tension is critical to preventing slippage. It’s important to note, however, that while over-tensioning the belt may seem like an easy fix, this should be avoided, as it can stretch and damage the belt, as well as put added stress on the motor.


   



    When there is not enough grip between the pulley and the belt, consider installing lagging. Lagging is a material added to the surface of the pulley for increased traction.


   



    Alternatively, a snub pulley may be installed. A snub pulley is simply an idler installed at a point which increases the arc between the belt and pulley to improve friction between the two.


   



    MATERIAL SPILLAGE


    Material spilling off of the conveyor is also a commonly encountered problem. While spillage can occur at any point along the conveyor path, not surprisingly, it is most common at load and transfer points.


   



    WHY SPILLAGE IS AN ISSUE


    As with other issues, material spilling off of the conveyor belt reduces productivity and efficiency, encourages product/material loss, and increases wear on equipment. Further, as mentioned, spillage can be a significant safety hazard, falling on employees and increasing the likelihood of employees slipping or falling.


   



    WHAT CAUSES SPILLAGE


    In general, it is not uncommon to see some level of material spillage. Excessive fugitive material, however, likely indicates an underlying issue. Typical causes of excess spillage include belt misalignment, belt damage or wear, high-impact loading, and chute misalignment.


   



    HOW TO PREVENT SPILLAGE


    Spillage in general is managed by a well-designed conveyor system. The use of skirtboards and dust pick-off points are useful in reducing the potential for material spillage.


   



    Ensuring that chutes are clear and located centrally above the loading zone will also help to prevent spillage. Additionally, impact beds for heavy loading prevent the belt from sagging, which can also release fugitive material.


   



    Keeping conveyors aligned and in proper working order will also help to prevent excess fugitive material from escaping, as any deviation from proper operation has the potential to spill material.


   



    PREVENTION IS KEY


    Any one of the aforementioned issues has the potential to cause serious problems: premature equipment failure, unexpected downtime, employee injuries, and more. Even if problems do not reach a high level of severity, however, they still represent unnecessary hazards and losses in productivity and efficiency. For these reasons, a preventative approach to conveyor problems is always the best policy.


   



    Regularly inspect the steel cord conveyor belt to look for signs of trouble: excessive material spillage, abnormal sounds, visual indicators, or other abnormalities. Always ensure that the equipment, as well as the surrounding area, are kept clean. Replace conveyor components that begin to show signs of wear.


   



    By taking these measures, the potential for unexpected downtime and lengthy repairs is greatly reduced.


   



    CONCLUSION


    Troughed belt conveyors offer reliable handling in nearly any setting, but they can occasionally exhibit issues, particularly if not kept clean and maintained; carryback, mistracking, slippage, and spillage are some of the most commonly encountered issues when working with belt conveyors. While each issue presents significant risk and potential for damage, these issues are largely prevented by keeping a close eye on conveyor operation and performance, and promptly addressing any issues that arise.


   



    FEECO manufactures custom belt conveyors and conveyor systems for use in nearly every industry, with expertise around hundreds of materials. Our Customer Service Team offers a full range of services for conveyors, from replacement parts, to repairs, and even inspections and conveyor audits. For more information on our belt conveyors or conveyor parts and service support, contact us today!

Tiller mortality and its relationship to grain yield in spring wheat

    Tiller mortality and its relationship to grain yield in spring wheat


    A primary determinant of grain yield in barley (Hordeum vulgare L. emm. Lam) is the number of ear-bearing tillers per plant at harvest, which depends both on the production of tillers and on their subsequent survival to form ears. This three-year field study compares tiller production and survival in relation to final grain yield in three types of barley: 2-rowed winter (2rw), 6-rowed winter (6rw) and 2-rowed spring (2rs), grown in two contrasting environments. These three types differed significantly in shoot and ear number, the winter barleys showing higher tiller production, with the maximum number of tillers ranging from 798 to 2315 m?2 in 2rw, 711 to 1527 in 6rw and 605 to 1190 in 2rs. Grain yield across environments and years was strongly correlated () with the number of ears at harvest. The maximum number of shoots produced by each type of barley was inversely related to the mean temperature during the tillering phase. Tiller mortality was inversely related to the maximum shoot production, being significantly lower in barleys with less tillering capacity, i.e. the spring type (with average values of 34.3% and 42.7% in the two environments). The highest tiller mortality occurred before anthesis and, to a lesser extent, from anthesis to maturity. These data support the hypothesis that the principal cause for tiller mortality in barley grown under Mediterranean conditions is the competition between tillers for a limited supply of resources.


   



    Spikeless tillers of wheat (Triticum aestivum L.) affect grain yield because of less than optimum effective plant population. This study was conducted to examine the genetic variability for tiller mortality, and its relationship to grain yield in diverse wheat lines. Twenty lines were evaluated in replicated field tests in 4 years at Rampur, Nepal. The characters investigated were maximum number of tiller produced, the number of reproductive tillers, tiller mortality, and grain yield. The lines differed significantly for all characters. The tiller mortality ranged from 7 to 30%. There were substantial effects of environment on all four characters. The entry-by-year interactions were significant for all traits, primarily because of changes in the relative genotypic differences for these traits in the four years. However, certain lines consistently ranked low or high for tiller mortality. There was a significant negative correlation between front tine tiller and grain yield in 3 out of 4 years. There was a positive correlation of highest tiller number with reproductive tiller number and with tiller mortality. Grain yield showed a nonsignificant positive correlation with maximum tiller number. The reproductive tiller number was positively correlated with grain yield. Results of this study indicate that spikeless tillers contribute negatively to grain yield and that genetic variation exists for tiller mortality in spring wheat.


   



    Vegetative growth in the form of tillers is crucial to final yield in winter wheat (Triticum aestivum L.). To understand the impact management practices have on tiller initiation, a study was conducted using two seeding rates (1.9 × 106 vs. 6.8 × 106 ha?1) and two N timing applications (single vs. split). Tillers initiated in the fall made up the majority of spikes compared to tillers initiated from 1 January to the start of jointing (GS 30). Tillers initiated in March at either seeding rate produced very few kernels spike–1, low kernel weight, and contributed little to yield. At the high seeding rate, tillers initiated prior to 1 January were responsible for more than 87% of the grain yield. Tillers produced in January– February produced 5 to 11% of the final yield, while tillers produced in March contributed less than 2%. In contrast, at the low seeding rate tillers produced in January–February made up 20 to almost 60% of the final yield. Overall, this study shows the timing and rate of leaf initiation impacts yield and yield components. Earlier tillers have an advantage in that they have shorter periods of leaf development that result in more leaf area which in turn supports more kernel spike–1 and heavier kernels, thus more grain weight per spike. Timing of N (single vs. split) application resulted in no significant impact on tiller development, spike number, kernel number, kernel weight, or grain yield.


   



    The number of spikes ha–1 is a critical yield component of wheat yield. Two factors contribute to the total number of spikes ha–1 at harvest, number of mainstem (MS) spikes and number of tillers plant–1. The number of tillers produced per plant is controlled by the environment during the period of tiller development from three-leaf stage to jointing (GS13–GS30) (Klepper et al., 1982) and the amount of tiller mortality that occurs from jointing to anthesis (GS30–GS69) (Jewiss, 1972; Rawson, 1971). Recent research has shown that the timing of tiller initiation and management factors such as seeding rate influence the rate of leaf development on each tiller which, in turn, influences tiller size and mortality (Tilley et al., 2015). The timing of tiller initiation and management factors such as planting date (Oakes et al., 2016) that promote leaf development could also influence other yield components such as kernels spike–1 and kernel weight. An understanding of when the most spikes are formed and the management factors that promote tiller formation during this critical period would help growers improve wheat yield.


   



    Tillers can be formed at multiple nodes on the MS, and secondary and tertiary tillers can form from nodes on the tillers themselves (Klepper et al., 1982; Evers and Vos, 2013). Under glasshouse conditions Klepper et al. (1982) found that once a tiller is initiated, leaf development on the tiller proceeded at the same rate as leaf development on the MS. However, subsequent research has found that leaf development on each tiller proceeds at a slower rate than that on the MS or even on preceding tillers (Tilley et al., 2015). This indicates that tillers initiated first will always have an advantage in growth and development compared to those initiated later. This advantage will increase as time passes resulting in more leaf area. It is likely that tillers with more leaf area will produce more kernels, heavier kernels, and will be less likely to be lost to tiller mortality.


   



    Timing of tiller initiation can also influence tiller mortality. Charles-Edwards (1984) concluded that self-thinning within plant communities is largely due to the lack of assimilate needed to continue growth and development within the individual stem which, in turn, can lead to a decrease in plant weight and eventually a decrease in plant yield. Some works have explored the purpose of rear tine tiller and the effects it may have on the plant as a whole and concluded tillers that abort may have benefited the plant due to assimilate and nutrient accumulation (Lupton and Pinthus, 1969; Palfi and Dezsi, 1960). However, Langer and Dougherty (1976) concluded that dead tillers had a negative effect on grain yield due to competition for assimilates and nutrients (Sharma, 1995).


   



    Management practices such seeding rate and N application timing can influence the timing and rate of leaf and tiller development (Bauer et al., 1984; Tilley et al., 2015) and grain yield. Tompkins et al. (1991) concluded that grain yields will decline as seeding rates decline. This in part is due to a decrease in spikes. However, it was determined that grain yield can decrease at high seeding rate (HSR) (Gooding et al., 2002) due to a decrease in kernels spike–1 and a decrease in kernel weight (Puckridge and Donald, 1967; Tompkins et al., 1991). Tilley et al. (2015) found that seeding rates influenced the rate of leaf development. Phyllochron intervals (PI) were shorter for each tiller at a low seed rate (LSR) compared to the same tillers at a HSR. This resulted in more leaves on each tiller, more tillers produced and fewer tillers lost to tiller mortality.


   



    Nitrogen is recognized as a vital nutrient needed for growth and development (Miller, 1939; Wilhelm et al., 2002). Nitrogen application timing recommendations for winter wheat in North Carolina (NC) are based on the tiller density (Weisz et al., 2001, 2011). Winter split applications are encouraged if tiller density <550 m–2. Otherwise the standard NC recommendation is to apply N at GS 30, the time when the wheat stem begins to elongate. Maidl et al. (1998) confirms that early N application increased plant density and concluded that N fertilizer treatment applied during stem elongation not only reduced tiller mortality but also led to high grain yield in both MS and tillers.


   



    To understand the impact of the timing of tiller initiation and management practices on kernel development and yield, a method of counting and marking leaves and tillers was created to monitor tiller growth and decline. This monitoring of individual tillers resulted in the ability to measure the number of heads, kernel number and kernel weight each tiller produced, and its contribution to final yield. The objectives of this study were to: (i) measure yield and yield components of tillers initiated at different periods during the growth of wheat and how tillers initiated at different periods contribute to overall grain yield, and (ii) determine the impact of seeding rate and timing of N applications on the productivity and sustainability of tillers initiated at different periods during the growth cycle of wheat.


   



    MATERIALS AND METHODS


    Field Experiment


    Field experiments were conducted at two sites in eastern NC and one site in western NC. At the Tidewater Research Station (TRS) in Plymouth, NC, experiments were conducted in 2009, 2010, and 2011. On a private farm in Beaufort County (BC) experiments were conducted in 2009 and 2010. On the third site in western NC (Piedmont Research Station [PRS] in Salisbury, NC) a single trial was conducted in 2011. The soil at TRS was a Cape Fear loam (clayey, mixed, thermic Typic Umbraqult) soil. At the BC site in 2009 and 2010 the experiment was conducted on a Cape Fear fine sandy loam (clayey, mixed, thermic Typic Umbraqult). The 2011 experiment at PRS was conducted on a Mecklenburg clay loam (fine, mixed, thermic Ultic Hapludult). In 2009, plots were planted on 3 November at TRS and 4 November in BC. In 2010, plots were planted on 10 November at TRS and 11 November in BC. In 2011, plots were planted on 10 November at TRS and 15 November at PRS.


   



    At each site, Pioneer 26R12, a high yielding wheat variety in NC, was planted in 16.9-cm rows into a conventional tilled field following corn. The experimental design at all sites was a split plot design with main plots consisting of two seeding rates, 1.9 × 106 and 6.8 × 106 ha–1, and subplots consisting of 134 kg N ha–1 applied either as a single application in March or a split application with half applied in late January or early February and the remaining half applied by late March. In 2009–2010, the first N application was made on 15 February with the second split and single N application made on 22 March. In 2010–2011, the first N application was applied on 4 February while the remaining split and single applications were completed on 18 March. During the 2011–2012 growing season at TRS, the first split application was applied on 19 January with the final split and single N applications applied on 12 March. Applications at the PRS were applied 1 wk later on 26 January and 19 March. All treatments were replicated five times.


   



    Disease pressure was minimum across all three site years and did not reach current threshold recommendations (Weisz et al., 2011). However, weed and insect control practices were applied. In 2009–2010 at TRS, thifensulfuren-methyl/tribenuron-methyl was applied POST at 0.04 kg a.i. ha–1 on 8 Mar. 2010. The BC location received the same application on 9 Mar. 2010. In 2010–2011 at both TRS and BC, thifensulfuren-methyl/tribenuron-methyl was applied POST at 0.04 kg a.i. ha–1 on 14 Mar. 2011. In 2011–2012 at TRS, mesosulfuren-methyl was applied POST at 0.33 kg a.i. ha–1 on 6 Dec. 2011 and thifensulfuren-methyl/tribenuron-methyl applied POST at 0.05 kg a.i. ha–1 on 1 Jan. 2012. At the PRS, chlorsulfuron/metsulfuron-methyl was applied PPE at 0.03 kg a.i. ha–1 on 3 Nov. 2011 and thifensulfuren-methyl/tribenuron-methyl was applied POST at 0.05 kg a.i. ha–1 on 28 Feb. 2012.


   



    Individual plots were 24.4-m long and 1.98-m wide equaling a total of 48.31m2. Each plot was divided into three sections. The first 18.01 m2 section was designated for grain yield and grain sampling. This section of the plot was harvested using a Gleaner K2 combine with a Harvestmaster Graingage (Juniper Systems, Logan, UT) that recorded moisture, grain weight, and test weight. The TRS in 2010–2011 was harvested on 20 June and on 22 June during 2011–2012. Beaufort County in 2010–2011 was harvested on 23 June and PRS was harvested on 29 June during the 2011–2012 season. Grain weight was adjusted to 15.5% moisture before calculating yield.


   



    The second section equaling 9.12 m2 was designated for marked samples. Five plants from each plot were marked and the number of full and partial leaves on each MS and tiller were recorded along with the total number of tillers at current growth stage. This was done once a month from planting to harvest. Throughout the 2009–2010 growing season, observations were made at TRS and BC on 22 December, 28 January, 1 March, 19 March, 7 April, and 26 April. During the 2010–2011 growing season, observations were made on 7 December, 31 January, 4 March, 2 April, and 30 April. During the 2011 growing season, leaf and Garden Tiller and Cultivator counts were recorded on 9 December, 2 January, 11 February, and 3 April at TRS and 15 December, 9 January, 24 February, and 13 April at PRS. Each new and existing tiller was noted using either a black, silver, or red permanent marker to mark leaf number. Black markings represented tillers that were initiated from planting through the end of December. Silver markings represented early winter tillers that developed from the first of January to the beginning of March. Red markings represented late spring tillers produced from March till growth stage GS30. The three colors used to track tillers helped categorize each individual tiller and determined whether or not they initiated in the fall, winter, or spring. Furthermore, tillers were marked on each subsequent leaf to track the number of leaves produced throughout the growing season. Harvest samples were taken in 2010–2011 and 2011–2012 at TRS, BC, and PRS on the same dates that the larger plots were harvested. At harvest, each of these five plants were clipped and placed in individual bags. For each plant, the MS and tillers were separated by color markings (black, silver, red) counted and hand threshed to determine the number of spikes and grain weight spike–1 for each tiller initiation period. The data for all five plants were averaged to represent values for each plot.


   



    The last 21.18 m2 of each plot was reserved for destructive sampling. Method for destructive sampling consisted of a 2-m stick and a garden shovel. A trench, encamping an area of 0.33 m2, was carefully dug around plants to a depth of 15 cm and the plants were then excavated from the destructive sampling area. Samples were taken on 17 June 2010, at TRS and BC. On 15 and 20 June 2011, destructive samples were taken at TRS and BC. Destructive samples were taken at TRS and PRS in 3012 but were destroyed before they could be processed. Leaf counts were taken from each individual stem and recorded. Leaf numbers were determined by counting the nodes on the plant. This was done by splitting the plant at the base and finding the small (0.6–1.25 cm) gap between the compressed nodes and the first separated node. The first separated node was counted as the fifth node (fifth leaf) and subsequent nodes (leaves) were counted in ascending order. Plants were separated into classes corresponding to the periods of tiller initiation (black, silver, and red) based on leaf number and the ratio of stems found in each initiation period in the marked samples. This ratio was determined by counting the number of MS or tillers from each category (black, silver, and red) in the five marked plants described above and dividing that number by the total number of MS or tillers produced in these same plants. Using the ratio of MS or tillers that were initiated from planting to the end of December (Black), the same ratio of plants with the highest leaf numbers in the destructive sample were designated as having been initiated during this period. Plants with the next highest leaf number were considered initiated during the period from 1 January to the end of February; and plants with the fewest leaves were considered initiated after 1 March. Spikes from samples representing each initiation period were hand threshed and grain weight, kernel number and 100 kernel seed weight were measured.


   



    Statistical Procedures


    For the marked plant samples the data taken from TRS in 2010–2011 and 2011–2012 at BC in 2010–2011 and PRS in 2011–2012 were analyzed using a repeated measures design with the Proc Mixed procedure in SAS (SAS Institute, Inc., Cary, NC) to determine if there were differences in the number of spikes plant–1 and grain weight spike–1 among site-year, tiller initiation periods (planting to 31 December, 1 January to 28 February, and after 1 March) seeding rate, and N application timing. In all cases, site-year, seeding rate and N timing were treated as fixed effects, while blocks and the interactions with blocks were treated as random. When differences were detected, Fisher’s Protected LSD was used to separate means.


   



    In the destructive sample plots some samples were lost in 2011–2012. Therefore, only samples taken in 2009–2010 and 2010–2011 at TRS and BC were used in the analysis. The Proc Mixed procedure in SAS (SAS Institute, Inc.) was used to determine if there were differences in spikes m–2, kernels spike–1, weight per 100 kernels, and grain yield among site-years, mini power tiller tractor initiation period, seeding rate and N application timing. As with previous analysis, site-year, seeding rate, and N timing were treated as fixed effects; while blocks and the interactions with blocks were treated as random. When differences were detected, Fisher’s Protected LSD was used to separate means.


   



    Grain yield from the large 18.01 m2 section of each plot for the 2010–2011 and 2011–2012 seasons at TRS and BC were analyzed using the Proc Mixed procedure in SAS (SAS Institute, Inc.) to determine if there were differences in grain yield among site-years, seeding rate, and N application timing. These site-years were chosen so that the grain yield from the large samples could be compared with that calculated from the small 2-m samples.

Solving problems on the tube mill

    Solving problems on the tube mill


    Tube mill machine line face a variety of challenges every day in their effort to produce high-quality tubing in a cost-effective and productive way.


   



    This article examines some of the typical problems producers encounter, some common causes of these problems, and some ideas for how to solve these problems.


   



    Lost Mill Time During Operation and Changeovers


    Often, excessive downtime during normal operation or tooling/job changeover can be attributed to one or more of the following causes:


   



    1. No written procedures for setup. Every mill should have written procedures for all operators to follow. The machine, tooling, and steel are fixed factors in the mill setup equation; the only variable is the human factor. This is why it is so important to have written procedures in place to control the process. Written procedures also provide a tool for troubleshooting when problems arise.


   



    2. No setup chart. Tweaking the mill during setup loses valuable setup time. Operators must work the tooling the way it was designed. This means setting up to the parameters of a setup chart.


   



    3. Lack of formal training. Formal training helps operators perform the procedures for carbon steel tube mill machine and maintenance and ensures that all operators are on the same track.


   



    4. Disregard of parameters from previous setup. If the Galvanized tube mill machine has been set up according to the written procedures and setup chart, the operator can write down the numbers from the digital readout on the single-point adjustment (SPA) unit, allowing the next operator to set up where the first left off. Setting up to the numbers can save as much as 75 percent of total setup time, as long as all the other tips discussed in this article are followed.


   



    5. Mill in poor condition. A poorly maintained mill costs valuable time and scrap during setup and operation. The mill must be dependable so that the operator is not chasing mechanical problems during normal operation and setup. A good maintenance program, as well as rebuilds or upgrades when necessary, is essential.


   



    6. Mill in misalignment. Tube mill misalignment, poor mill condition, and inaccurate setup account for 95 percent of all problems in tube production. Most mills should be aligned at least once a year.


   



    7. Tooling in poor condition. Operators must know how much life is left in the tooling before the next scheduled rework. Running the tooling until it cannot produce tubing anymore not only wastes valuable mill time, but produces scrap and affects delivery schedules. All tube production companies should have a tooling maintenance program in place.


   



    Any of these causes of lost time on the mill can have varying degrees of value, depending on the severity of the conditions. The bottom line is, the more of these items that are in control, the less downtime on the mill.


   



    Splitting in the Weld Zone


    Weld zone splitting can be a result of some or all of the following:


   



    Overly narrow strip with insufficient material to forge


    Poor alignment or setup


    Insufficiently worked fin passes, so the edge is not prepared for welding


    Poor slit edge


    Off-center strip approach (strip rolled over) to the weld box, preventing forging between the weld rolls


    Nonparallel edges entering the welding machine


    Inappropriate weld power for mill speed


    Poor-quality steel with improper chemistry


    Irregular Size in the Sizing Section


    When irregular size occurs in the sizing section, the problem may not necessarily be in the sizing section itself. The operator also must check the setup in the breakdown, fin, and welding section of the mill to ensure proper presentation to the sizing section. If the forming section sends improperly formed tube to the sizing section, irregular tube size can result.


   



    The operator also should check for bent shafts, oversized bores on the tooling, or undersized outside diameters (ODs) on the driven shafts. The integrity of the side roll boxes also should be checked.


   



    In addition to these checks, the operator should consider the following questions:


   



    Is the weld size in accordance with the setup chart?


    Is the weld size round?


    Are the strip edges parallel, with no step going into the weld rolls?


    Is the weld scarf smooth?


    Are rework shims installed under the bottom driven shafts to maintain the metal line?


    Are the correct spacers installed on the driven shafts and to the correct length?


    Are the bearings and bearing blocks tight?


    Are the side rolls parallel?


    Is the tube being cooled properly?


    Are all the drives coordinated and adjusted to match the rework of the tooling?


    Has the chemistry or hardness of the material changed?


    Weld Chatter


    Weld chatter is the inability to achieve a clean cut of the outside weld bead after welding. The scarf knife chatters and produces a ribbed or rough cut on the OD of the tube. This is unacceptable in most of the end products produced by the tube and pipe industry.


   



    Several techniques can be used to prevent weld chatter.


   



    The scarf knife should have a slightly larger radius than the tube OD. This will provide a concentric, clean cut.


   



    An ironing pass should be used after the scarf stand. As the name implies, this stand irons out any hot imperfections the scarf knife may leave behind. It also adds a tremendous amount of stability to the scarfing operation.


   



    On mills that employ induction welding, moving the induction coil upstream a bit and away from the weld rolls helps temper the edges of the strip by preheating them before welding. This results in a more malleable material that is softer and easier for the scarf knife to cut.


   



    The heel of the scarf knife or insert should be ground to an angle of 18 degrees from the horizontal, and the tool should be set at an angle of 15 degrees from the vertical. This provides the proper clearance so the knife does not drag on the tube or pipe. A straight up-and-down approach to the tube or pipe invites chatter.


   



    In general, several tube mill components should be checked on a regular basis. This should be done at least monthly, but should be based on the usage. A higher production rate or running heavier metals through the mill requires more frequent checks. Shafts should be checked for OD, looseness, bending, and parallelism. Shoulder alignment should be checked, and the integrity of the entry table, drive stands, side roll boxes, weld box, and Turk's head units should be ensured. Of course, rolls should be checked to ensure they have been installed on the correct stands.


   



    Once a year, the mill should be aligned. A mill alignment usually takes one or two days and is most often done by a professional. Every day, the mill operator should use a setup chart and follow all operating procedures.


   



    The operator also should know the chemistry, Rockwell hardness, width, and thickness of the strip entering the mill and should document these values. Tube size should be measured between each pass.


   



    Most important, for high-quality, consistent results in tube producing, an operation standard should be established for all employees to follow.


   



    High‐frequency welded carbon tube mill machine line is designed to produce round tube diameter of 10.0 – 38.1mm, and wall thickness of 0.4 ‐1.8mm.This line utilizes roll forming to process steel strip into various shapes. Using high frequency induction heating, this line is capable of producing section material of various diameters and sizes by squeezing weld seam together into closed shape. The application of advanced aperture technology, PLC automatic control system and British Eurasia Digital speed‐regulating unit ensure that the production line works reliably and operates and maintains easily.


   



    Every detail is the evidence of showing our company's strength and works's hardworking and it is the basical assurance of every machine we are producing.We are targeting to provide our customers with high-quality equipment or machines.


   



    Botou Boheng Metallurgical Equipment Manufacturing Co.,Ltd was established in 2003, and located in Botou city Hebei province. Boheng is a high and new-techonology enterprise specialized in design,development and manufacture of ERW welded pipe equipment,high precision slitting & crossing-cutting equipment,spiral welded pipe equipment,cold forming equipment and crossing-cutting equipment,spiral welded pipe equipment,cold forming equipment and rollers. Boheng is the pioneer that had the key processing technology of the international advanced whole set welded pipe mill. Boheng always adhere to the enterprise policy &quot;contribute to the society with excellent techniques,high quality products and perfect service&quot;.


   



    Technology capability:


   



    (1)Engineer able to service overseas


   



    (2)Work out reasonable investment scheme,selecting rational model unit


   



    (3)Provide free equipment layout,factory planning for you


   



    (4)Provide free equipment foundation drawing,if necessary,offer technical guidance on-site for equipment foundation construction


   



    (5)Provide equipment installation and commission,ensure the normal operation of production line


   



    (6)Provide professional technical training to help your stuff familiar with equipment ASAP

Cotton Buds Making Business

    Cotton Buds Making Business


    The&nbsp;cotton swab making machine business is rapidly progressing in India. Cotton is the staple fiber made from the natural fibers of cotton plants. The cotton made from the genus Gossypium is primarily composed of cellulose, which is an insoluble organic compound that is a soft and fluffy material. Cotton is the most important fiber crop, which provides the basic raw material to the cotton textile industry. Cotton is grown in tropic and sub-tropic parts and requires uniformly high temperature and is a Kharif crop; it is sown and harvested in different parts of India depending upon the climatic conditions.


   



    China, the USA, and India are the world’s major cotton-producing countries, accounting for about 60% of the world’s production. China alone consumes around 40% of the world’s cotton, and it is a significant export revenue source for major cotton-producing countries of the world.


   



    Cotton is cultivated around 117 lakh hectares in India and accounts for about 37.5% of the global cotton area, and contributes to 26% of the global cotton production. Cotton holds an essential place in the Indian textile mills, and it is used as a primary raw material of India. Cotton provides livelihood to around 60 million people of India by means of cotton cultivation, processing, marketing, and exports.


   



    Cotton buds are the most common item which is used for cleaning the ear, first-aid, cosmetic application, cleaning, and arts and crafts. The cotton buds are composed of small wads of cotton which are wrapped around a rod made of wood, paper, or plastic. The cotton buds were developed in 1923 by a Polish-American Loe Gerstenzang which later became the most widely sold brand name of cotton swabs.


   



    The cotton bud with a single tip on a wooden handle is mostly used in medical settings and is the traditional cotton buds. The cotton buds used for domestic purposes are usually short, about 3 inches long, and double-tipped. Traditionally, the handles of the cotton buds were made of woods while later it was made of the rolled paper and sold in large quantities. The cotton buds are available in a wide variety of colors, such as blue, pink, or green. The manufacturing of the test swabs in a record time of seven days is a dream come true under the ”Make in India” initiative which has conceptualized the production and provided employment to so many unemployed people in India.


   



    The cotton buds are most commonly used for cleaning the ear by removing earwax.&nbsp; The cotton buds are used for domestic purposes such as cleaning and arts and crafts purposes. The medical buds are used to take microbiological cultures which are usually rubbed into the affected area and wiped where the bacteria grows across the culture medium. They can also be used to apply medicines to selective areas targeting to remove substances or clean them. They can be used as an applicator for applying cosmetics, ointments, or other substances.


   



    The cotton buds are also used to take the DNA samples by scraping cells from the inner cheek in the case of humans. The cotton swabs are also often used in the construction of the plastic model kits while paintings. They are also frequently used for cleaning the laser diode lens of an optical drive in conjunction with rubbing alcohol. In addition to his, they are used to clear the large parts of the computer such as video cards and fans and also used widely to clean video games cartridges in the past.


   



    With so many uses, the demand for cotton buds in the market is growing at a rapid rate and is an essential tool for the healthcare of all individuals irrespective of age, race, culture, or religion, etc. keeping this in mind, the idea to start the automatic cotton swab making machine business is a golden opportunity for the young and aspiring entrepreneurs.


   



    With the increased diversity of product ranges from adult-centric to baby and child-centric and increased popularity of cotton buds in the modern as well as in traditional retailing has increased the sales of the cotton buds to grow. With the rising demand, the locally produced cotton buds have become popular across rural India. it has also become popular in small as well as in metropolitan cities because of the availability of the cotton buds at a much lower price as compared to the branded products have been a key focus for the small manufacturers in India. Therefore, it is an ideal business for employing in the Rural areas as well as it will promote the ‘Make in India” initiative of the Modi Government.


   



    The Government of India is promoting all the manufacturing units, especially in the areas where China enjoys a big share in the global market. The government to achieve the Atma Nirbhar Bharat is pushing the exports by giving various aids to the small and marginal businessmen and it aims to reduce the dependency of the country on the imported goods.


   



    The government through various joint ventures and supporting the local businesses is expanding India’s share in the global market. Keeping this in mind, the government has announced various production-linked incentives for manufacturing the earbuds. This is a great opportunity for Indian earbuds manufacturers to raise their business. It is a big step towards making India self-reliant and manufactures their products. Almost 260 schemes are contracted by the Tri-services at an approximate cost of Rs. 3.5 lakh crores and with the latest embargo on the import of 101 items, the contracts worth Rs 1, 30,000 crore is expected to be placed upon the domestic industries in India.


   



    Registration:- To start the buds manufacturing business in India, the first and foremost thing is the registration of your firm either as a proprietorship company or as a partnership firm. One must register the company as a Proprietorship firm if he has to start his buds manufacturing business as One Person company. To start a partnership firm, one must get registered with the Registrar of companies (ROC) and register as a Limited Liability Partnership (LLP) or the Private Limited Company.


   



    GST Registration:- To start a business, it is now mandatory for any business to obtain a GST number, tax identification number, and an insurance certificate.


   



    License for Trade:- Trade license is very important to be acquired to start a buds manufacturing business. It can be obtained from the local bodies of the respective states.


   



    MSME or SSI Registration:- To avail of the government schemes and benefits, one must obtain the MSME or SSI registration. This will help the businessman to receive all the governmental benefits arising from various schemes.


   



    Trademark:- It is required to make sure to register the buds manufacturing business with the trademark which will help in protecting the brand name.


   



    Before starting a semi automatic cotton swab making machine business, one has to make sure to select the proper machines which are proper for operations suitable for your business.


   



    Following are the description of machines used in the cotton buds making business-


   



    Automatic Cotton Swab Packing Machine : –


    The automatic cotton bud making machine is the machine that uses the computer PLC process control and warm wind drying technology is used to help to absorb the coating layer. The microcomputer servo motor aids feed the cotton layer and wrap the absorbent material. In this technology, there is no requirement for a different packaging machine separately.


   



    Spindle Fabrication Machine : –


    The paper spindles are processed with the help of a dyeing cutting machine from a heavy grade paper and then a thin layered paper is rolled around it to make it light. While a wooden spindle is developed with the help of a lathe machine process. The plastic spindle is made from the extrusion molding process machine, where the plastic is melted and extruded through a die and sent to a hopper machine.


   



    Packaging Machine : –


    The cotton buds are sent through the packaging wheels where the buds are rolled with the pouch. A sensor is attached to the packaging wheel which counts the buds and places them into the packaging bag which is packed with the packaging wheel.


   



    The automatic cotton swab packing machine does not require a lot of space for its operation and it can be started from home. Anyone can start the business even from home this will reduce the cost of investment. The cotton buds making business has the potential to give a good place in the market by becoming a high profit earning business in a short period. With the increased demand for cotton buds, the business is very ideal for start-ups and young entrepreneurs.


   



    In the times like this where the pandemic has left no nation in a mess, India has started the manufacturing of indigenous swabs or cotton buds for the testing of Covid-19. A Mumbai based Micro, Small and Medium Enterprise (MSME) and Tulips has got a green signal from the Indian Council for Medical Research (ICMR) and the National Institute for Virology in Pune. These firms have started manufacturing the polyester-spun swabs which are way cheaper than the imported swabs from the US and China. This has helped various small and indigenous manufactures to retain their livelihood and it has also resulted in producing cheaper testing kits at an affordable price.


   



    We Indians have in reality converted the deadly pandemic into an opportunity and the government through various initiatives has been aiding the cotton buds making business. The government is also being aided by various Non-governmental Organisations like Aatmnirbhar Sena is working very hard to provide finances and cheap credit to aspiring and innovative minds and fulfilling their dream of starting the business.&nbsp;


   



    Therefore, the growth and development of cotton and cotton made products has a vital role in the overall development of the Indian economy.

Making process control valve choices

    Making process control valve choices


    Today’s process control valves offer an ever wider range of features and benefits for industries that require precise control over fluids, steam and other gases. With so many control valves to choose from it is important to establish the features that will deliver the most cost-effective design for a particular application.


   



    Control valves are used to manage the flow rate of a liquid or a gas and in-turn control the temperature, pressure or liquid level within a process. As such, they are defined by the way in which they operate to control flow and include globe valves, angle seat, diaphragm, quarter-turn, knife and needle valves, to name a few. In most cases the valve bodies are made from metal; either brass, forged steel or in hygienic applications 316 stainless steel.


   



    Actuators will use an on-board system to measure the position of the valve with varying degrees of accuracy, depending on the application. A contactless, digital encoder can place the valve in any of a thousand positions, making it very accurate, while more rudimentary measurements can be applied to less sensitive designs.


   



    One of the main areas of debate when specifying globe control valve is determining the size of the valve required. Often process engineers will know the pipe diameter used in an application and it is tempting to take that as the control valve’s defining characteristic. Of greater importance are the flow conditions within the system as these will dictate the size of the orifice within the control valve. The pressure either side of the valve and the expected flow rate are essential pieces of information when deciding on the valve design.


   



    Inside the valve body, the actuator design is often either a piston or a diaphragm design. The piston design typically offers a smaller, more compact valve which is also lighter and easier to handle than the diaphragm designs. Actuators are usually made from stainless steel or polyphenolsulpide (PPS), which is a chemically-resistant plastic. The actuator is topped off by the control head or positioner.


   



    Older, pneumatically operated positioners had a flapper/nozzle arrangement and operated on 3-15psi, so no matter what the state of the valve, open closed or somewhere in between, the system was always expelling some compressed air to the atmosphere.


   



    Compressed air is an expensive commodity, requiring considerable energy to generate and when a manufacturing line is equipped with multiple process control valves all venting to the atmosphere, this can equate to a considerable waste of energy. It is important to not only establish the most appropriate valve design, but also a cost-effective solution that takes account of annual running costs.


   



    Modern, digital, electro-pneumatic valves that use micro-solenoid valves to control the air in and out of the actuator have introduced significant improvements for operators. This design means that while the valve is fully open, fully closed or in a steady state, it is not consuming any air. This, and many other engineering improvements, have made substantial advances in both economy and precision.


   



    Flexible designs


    Valve seats can be interchangeable within a standard valve body, which allows the valve to fit existing pipework and the valve seat to the sized to the application more accurately. In some cases, this can be achieved after the valve has been installed, which would enable a process change to be accommodated without replacing the complete valve assembly.


   



    Selecting the most appropriate seal materials is also an important step to ensure reliable operation; Steam processes would normally use metal-to-metal seals, whereas a process that included a sterilization stage may require chemically resistant seals.


   



    Setting up and installing a new valve is now comparatively easy and much less time-consuming. In-built calibration procedures should be able perform the initial setup procedures automatically, measuring the air required to open and close the valve, the resistance of the piston seals on the valve stem and the response time of the valve itself.


   



    Improving safety


    Control valves should be specified so they operate in the 40-85% range so if the valve is commanded to a 10% setting, it can detect if something has potentially gone wrong with the control system and the best course of action is to close the valve completely. If the valve is commanded to a position of 10% or less this can cause very high fluid or gas velocities, which have damaging effects on the system and cause considerable noise and damage to the valve itself.


   



    Modern control functionality can offer a solution that acts as a safety device to prevent damage to the process pipework and components. By building in a fail-safe mechanism, any valve position setting below a pre-set threshold will result in the valve closing completely, preventing damage to the surrounding system.


   



    Control inputs can also include safety circuits to ensure safe operating conditions within the process equipment. For example, if an access panel on a vessel containing steam is opened, an interlock switch will open and the valve controlling the steam supply to the vessel can be automatically closed, helping mitigate any risks.


   



    Improving reliability


    Many process control environments offer less than ideal conditions for long-term reliability. Moisture-laden atmospheres, corrosive chemicals and regular wash-downs all have the capacity to shorten the service life of a process Self regulating control valve. One of the potential weaknesses of the actuator is the spring chamber where atmospheric air is drawn in each time the valve operates.


   



    One solution is to use clean, instrument air to replenish the spring chamber, preventing any contamination from entering. This offers a defense against the ingress of airborne contaminants by diverting a small amount of clean control air into the control head, maintaining a slight positive pressure, thus achieving a simple, innovative solution. This prevents corrosion of the internal elements and can make a significant improvement to reliability and longevity in certain operating conditions.


   



    While choosing the most appropriate process control valve can be a complex task, it is often best achieved with the assistance of expert knowledge. Working directly with manufacturers or knowledgeable distributors enables process control systems to be optimized for long-term reliability as well as precision and efficiency.


   



    Damien Moran is field segment manager, Hygienic – Pharmaceutical at Bürkert. This article originally appeared on the Control Engineering Europe website. Edited by Chris Vavra, associate editor, Control Engineering, CFE Media and technology, cvavra@cfemedia.com.


    Control valves are generally present whenever fluid flow regulation is required. The three way and angle control valve reliability is critical to the control quality and safety of a plant. An improved dynamic and static valve behaviour would have a major impact on the process output. In order to assess the dynamic performance of the control valve, a computer model of an electro-hydraulic control valve is developed. And the control valve characteristics are investigated through the use of mathematical simulations of the control valve dynamic performance. The results show that the electro-hydraulic driven control valve, which is developed to regulate the mixed-gas pressure in combined cycle power plant, can meet the challenge of the gas turbine.


    Control valves play important roles in the control of the mixed-gas pressure in the combined cycle power plants (CCPP). In order to clarify the influence of coupling between the structure and the fluid system at the control valve, the coupling mechanism was presented, and the numerical investigations were carried out. At the same operating condition in which the pressure oscillation amplitude is greater when considering the coupling, the low-order natural frequencies of the plug assembly of the valve decrease obviously when considering the fluid-structure coupling action. The low-order natural frequencies at 25% valve opening, 50% valve opening, and 75% valve opening are reduced by 11.1%, 7.0%, and 3.8%, respectively. The results help understand the processes that occur in the valve flow path leading to the pressure control instability observed in the control valve in the CCPP.


   



    1. Introduction


    The steel mills generate vast amounts of blast furnace gas (BFG) and coke-oven gas (COG) in the production. In order to reduce the environmental pollution, some steel mills mix BFG with COG and build combined cycle power plants (CCPP) to make use of the gas [1]. For the normal operation of CCPP, the pressure of mixed gas delivered to the gas turbine should be kept in a steady range.


   



    In CCPP, control valves play important roles in the control of the mixed-gas pressure. The signal of mixed-gas pressure measured using the pressure meter is compared to the signal of the desired pressure by the controller. The controller output accordingly adjusts the opening/closing actuator of the control valve in order to maintain the actual pressure close to the desired pressure. The opening of the control valve depends on the flow forces and the driving forces of the control-valve actuator, while the flow forces and the driving forces are affected by the valve opening. Therefore, there is strong coupling interaction between the fluid and the control valve structure.


   



    According to Morita et al. (2007) and Yonezawa et al. (2008), the typical flow pattern around the Knife Gate Valve is transonic [2, 3]. When pressure fluctuations occur, large static and dynamic fluid forces will act on the valves. Consequently, problematic phenomena, such as valve vibrations and loud noises, can occur, with the worst cases resulting in damage of the valve plug and seal [4]. In order to understand the underlying physics of flow-induced vibrations in a steam control valve head, experimental investigations described by Yonezawa et al. (2012) are carried out. Misra et al. (2002) reported that the self-excited vibration of a piping system occurs due to the coincidence of water hammer, acoustic feedback in the downstream water piping, high acoustic resistance at the control valve, and negative hydraulic stiffness at the control valve [5]. Araki et al. (1981) reported that the steam control-valve head oscillation mechanism was forced vibration, while self-excited vibration was not observed [6].


   



    Those studies cited previously are mainly aimed at the modeling of the self-excited vibration, the analysis of vibration parameters stability, and so on [7–11]. Whereas, the studies on the influence of nonlinear fluid-structure coupling of control valve on the valve control characteristics, such as the pressure regulation feature, are still very limited [12–17]. In the CCPP, the valve control characteristics affected by the fluid-structure coupling are particularly important for the stability of the mixed-gas pressure control. It has not been uncommon to see that the instability of the mixed-gas pressure causes a severe disturbance or even an emergency shutdown of the whole plant, and the handling of such an emergency often becomes a source of new problems and confusion. In this paper, numerical investigations are carried out to clarify the influence of fluid-structure coupling of control valve on not only the flow field but also the gas pressure regulation and the natural frequency changes of the control valve. This study helps understand the processes that occur in the valve flow path leading to the mixed-gas pressure pulsations, which is valuable for the pressure stability control of the mixed gas in the CCPP.

How are hybrid inverters used in solar projects?

    How are hybrid inverters used in solar projects?


    This paper proposes a new configuration of a single-phase hybrid inverter with an integrated battery energy storage, which is suitable for residential households to maximize local consumption of solar energy and thus reduce dependency on grid support. The hybrid inverter is called Direct Storage Hybrid (DSH) Inverter. A transformer-less topology such as HERIC, operating at low frequency to generate a three-level rectangular output voltage, is adopted to connect a photovoltaic (PV) panel to the load and/or the grid. A series active filter is employed to compensate the high harmonic components from the rectangular voltage and provide a sinusoidal voltage. A bidirectional dc/dc converter connects the battery to the PV panel to control the battery state of charge (SoC) and optimize the PV panel operation during both off-grid and grid-connected modes. The DSH inverter can let the battery bypass the dc/dc converter and connect directly to the inverter stage, leading to a significant improvement in throughput efficiency in battery utilization. This paper discusses the operation and loss analysis of the DSH inverter in off-grid mode.


    This paper is designed in such a way that it overcomes this limitation by the use of solar energy. NA hybrid inverter lv with Solar Battery Charging System consists of an inverter powered by a 12V Battery. This inverter generates up to 230V AC with the help of driver circuitry and a heavy load transformer. This battery gets charged from two sources, first being the mains power supply itself and second from the solar power. If the mains power supply is available, then the relay switches to main power supply for supplying the load. This power supply also charges the battery for using it as back up the next time when there is a power outage. The use of solar panel to charge the battery gives an additional advantage of surplus power in case the power outage of mains is prolonging. Thus this inverter can last for longer duration’s and provide uninterrupted power supply to the user.


    Hybrid inverters are commonly used in the developing world, but they are starting to make their way into daily use in certain areas of the U.S due to their ability to stabilize energy availability.


   



    A solar inverter’s main job is to convert DC power generated from the array into usable AC power. Hybrid inverters go a step further and work with batteries to store excess power as well. This type of system solves issues renewable energy variability and unreliable grid structures.


    “Inverters for grid-tied applications can only provide power based on what the array can immediately generate from the sun,” explained Bryan Whitton, product manager at Darfon. “Hybrid inverters can store power in batteries and then drawn upon it as needed for energy stabilization.”


   



    Hybrid inverters can vary in size, performance and features. But Mara White, product manager for OutBack Power, said most models usually operate bi-directionally, meaning they can convert DC power from modules to usable AC power and then convert stored AC from the batteries to power loads when needed. “Hybrids can also remain grid-connected and use a mix of renewable and non-renewable energy to charge batteries and offset loads,” White added.


   



    Some contractors have used hybrid inverters in the residential, remote home applications for the past decade or two. But Allan Gregg, VP of applications engineering at GreatWall—which manufactures Satcon inverters—said the range of applications has expanded over the past few years to include large capacity microgrids as well as grid-connected systems.


   



    Historically, hybrid inverters have been used more frequently in developing countries that do not have access to a reliable power grid.


   



    “In North America and Europe, hybrid inverter-based systems are usually elective,” White explained. “Users choose to use them for storing energy for self-consumption or provide back-up power during emergencies. But in the developing world, hybrids are more of a necessity to compensate for weak or intermittent grids or a lack of grid electricity all together. Microgrids in places such as India, Asia and Africa are also driving na hybrid inverter hv adaptation.”


    Still, Whitton said hybrid models are beginning to be used on a more daily basis in areas of the U.S. where the grid is unpredictable, such as Hawaii, or in states where net-metering has been widely supported. “Applications with less than ideal solar characteristic are also good for hybrid-based systems because they can store power and redistribute it during peak times, improving payback,” he added. “Basically, if the site has the potential for losing the grid frequently, you should consider a hybrid for off-grid operation.”


   



    Having the flexibility of a hybrid system can add initial cost to a project, though experts say this can be offset by the ability to self-consume all of one’s available PV electricity.


   



    There are also important design considerations when using hybrid inverters. For example, Gregg warned that the battery bank voltage should be compatible with the DC input requirements of the inverter, and there should be enough solar capacity to supply the load as well as charge the batteries.


   



    Wiring can also be more complex when using hybrid inverters, especially when panels are dedicated for critical backed-up loads. “And as with any device that does several jobs at once, a hybrid inverter is usually slightly less efficient,” White added, “although, improvements in other balance-of-system components can compensate for that slight loss easily.”


   



    There are also specific electrical safety issues with any type of energy storage, so White recommended getting specialized training in energy storage techniques and design. “Most available training is focused on simple grid-tied systems because they have been the majority of U.S. solar installations until now,” she said. “But with incentives changing and the surge in energy storage interest and applications, it’s important to get ahead of the curve and get advanced training quickly.”


   



    Andrew McCalla of Austin, Texas-based Meridian Solar, a Solar Power World top contractor, said he commonly used hybrids in the mid to late ’90s when the now standard grid-tie inverter sector was just a glimmer. “I can imagine that, when regulatory hurdles are fabricated to limit the consumer and societal benefits of bi-directional power flow from distributed generation, these battery-based platforms will become far more common. What is old is new again!”


    Another segment of hybrid inverters includes inverters that can use two energy sources. For example, Ginlong offers a PV / wind lv battery hybrid inverter that has inputs for both sources, instead of having to use two inverters. In much of the United States, wind speeds are low in the summer when the sun shines brightest and longest. The wind is strong in the winter when less sunlight is available. Therefore, because the peak operating times for wind and solar systems occur at different times of the day and year, such hybrid systems have the potential to produce power when it’s needed, and reach a higher return on investment.


    When you first consider getting solar or battery storage on your home or business, one of the first things you will discover is that you will require an inverter and that there are many different types of inverters available. This article is designed to provide an introduction to the different kinds of inverters available and help you to understand which one will suit your installation. So what does an inverter do? Simply put an Inverter converts DC power to AC power. Solar panels produce DC power and batteries store DC, however most of our appliances run on AC power, as does the electricity grid. This is why all solar systems and battery storage systems need an inverter however there are several different types of inverters depending on whether or not energy storage batteries are required.


   



    On-grid solar installations are the most common and most affordable type of system available at present. These systems use a simple solar inverter, which convert the DC power from your solar panels into AC power which can be fed directly into the grid, or used in your home appliances.&nbsp;


   



    Off-grid and hybrid systems are much more complex because they involve both solar panels as well as battery storage. Multiple inverters are often required in these installations such as a solar inverter and sophisticated battery inverter/charger to manage both grid connection and the charging and discharging of the batteries. These advanced inverter/chargers are known as interactive or multi-mode inverters. However, in recent years a new type of inverter has become available which integrates solar and battery inverter technology into what is known as an all-in-one hv battery hybrid inverter.


   



    A micro-inverter is a very small inverter that is attached to the back of a solar panel. A micro-inverter only converts the power of one or two solar panels to AC so generally many microinverters are required in a single system. Micro-inverters have several advantages over string inverters including performance, safety and monitoring, however the upfront cost can be significantly greater. For more details about micro-inverters, check out our micro-inverters article.


   



    String solar inverters come in single phase and three phase versions although most residential homes in the US and Australia use single phase power, while many homes in Europe use 3-phase power, also all businesses and factories will have three phase power. As a general rule most String solar inverters between 1-6kW are single phase and greater than 6kW are usually three phase.


   



    As home energy storage systems have surged in popularity a new kind of advanced Inverter has emerged known as an hybrid inverter. Hybrid inverters combines a solar inverter and battery inverter/charger into one simple unit. These inverters are a very economical way to enable what is known as ‘self-use’ or 'load shifting' of energy. Allowing you to store solar or off-peak energy in a battery to be used during peak times. Although it is important to know that some all-in-one inverters cannot function during a power outage such as when there is a blackout. They can also have limited functionality and monitoring capabilities.The traditional off-grid solar system uses a simple battery inverter that converters DC power from a battery bank to AC power to supply your home or appliances, these systems need separate battery chargers and regulators. There are more advanced versions of these battery inverters with built in chargers known as inverter/chargers. In recent years very advanced inverters have become available which are inverter/chargers with in-built generator control systems, advanced monitoring capabilities and other features, these are known as interactive or multi-mode inverters. They are typically used in conjunction with a solar inverter to create what is known as an AC coupled system. You can learn more about these and other hybrid inverter types here.

Thanks to the existence of contact lenses, it can sometimes be impossible to tell if someone has a visual impairment or not. These lenses can make huge differences to the lives of their wearers, providing a certain level of freedom that traditional glasses are unable to.

According to the Centers for Disease Control and Prevention (CDC), around 41 million people in the US wear contact PC lenses.

While they might feel like a relatively modern invention, rigid contact lenses made from plastic were first manufactured in the US between 1938 and 1940. The soft contact lenses currently worn by an estimated 93% of contact lens wearers were first introduced in 1971.

On a personal level, I first started wearing them as a temporary measure when my declining eyesight made playing sports difficult. However, no longer having my vision affected by raindrops and fogging up (along with the boost in self-esteem that came from not wearing glasses) meant that contact lenses quickly became my main method of improving my vision.

But despite their prevalence and the benefits they can provide, many people (myself included) wear contact lenses in a way that can compromise eye health, increasing the risk of damaged corneas and infection from microbes.

This week has marked the second annual Contact Lens Health Week – a week organized by the CDC to increase public awareness and promote healthy wearing and caring of contact lenses. In this Spotlight, we take a brief look at a few of the “do’s and don’t’s” of contact wear. In addition, we will have a look at some of the interesting “can’s and can’t yet’s” of new contact lens innovations.

Healthy habits mean healthy eyes
Although they are similarly effective at improving vision as glasses, contact Pc anti fog lens wearers can be more at risk of eye complications than those who use glasses. If wearers do not follow contact lens care instructions properly, they can put themselves at risk of serious eye infections that can lead to blindness.

The CDC have previously reported that between 40-90% of contact lens wearers do not properly follow their contact lens care instructions, which may explain why serious eye infections affect around 1 in 500 contact lens wearers each year.

Many people compromise their visual health due to bad habits when it comes to wearing contact lenses. While it is easy to manhandle glasses, contact lenses need to be afforded a greater level of care.

This means washing hands with soap and water and drying them comprehensively before ever touching contact lenses. Doing so prevents the transfer of germs from the hands to the lenses and consequently the eyes.

Exposing the lenses to water should be avoided as water can carry bacteria and other microbes that cause infection. With soft contact lenses, water can also alter the shape of the lens and potentially damage the cornea. As a result, contact lens wearers should remove their lenses before showering, swimming or using hot tubs, as tempting as it may be to keep them in.

One particular germ, an ameba called Acanthamoeba, is typically found in tap water as well as other water sources. If it causes infection (Acanthamoeba keratitis), patients can require a year or more of treatment, and possibly a corneal transplant.

Another bad habit that should be avoided where possible – unless prescribed by a doctor – is sleeping in contact PC super blue cut lens. In addition to making the eyes feel uncomfortable, sleeping in any type of lens increases the wearer’s risk of a corneal infection known as microbial keratitis by between four and five times.

Fast facts about keratitis
Keratitis is inflammation of the cornea, the clear tissue that covers the pupil and iris
Keratitis can be caused by infectious microbes or by minor injuries to the cornea
In severe cases, keratitis can permanently damage an individual’s vision.
This risk extends to the wearers of contact lenses that are designed to be slept in. Recently, the story of a man who went blind in one eye after sleeping in contact lenses for almost a week has come to the media’s attention.

“The kind of contacts I have are called ‘Night and Day’ contacts,” Chad Groeschen explained to USA Today, “and it was my impression you could leave them in for 30 days straight. I figured the less I was messing with my eyes, the better.”

While people can opt to use disposable lenses that are designed to be worn daily, many choose to wear lenses that last for longer periods and need to be stored properly when not in use. Unsurprisingly, many eye problems arise from bad habits pertaining to the storing of contact lens and associated products.

Contact lenses need to be kept clean if they are going to be used for multiple days. Lenses should be cleaned using a specific contact lens disinfecting solution and never water or saliva, as should the case that the lenses are stored in when not in use.

The CDC report that fewer than half of contact lens wearers report always cleaning their contact PC blue cut lens cases, and the number of moderate to severe lens-related infection could be halved if case cleaning practices were improved. Contact lens cases should also be replaced at least once every 3 months.

Contact lenses are stored in a purpose-built solution that is recommended by an eye care specialist. Contact lens wearers should stick to the recommended solution as the recommendation will be based upon the wearer’s eyes and medical history. Water should never be used, again due to the fact that it can increase the risk of infection.

Old solution in a lens case should never be “topped off” with new solution – instead, only fresh solution should be used. Solution can become contaminated with microbes that cause infections, and simply adding fresh solution to old solution reduces how effective it is at eradicating germs.

According to the results of a recent CDC study, these bad behaviors are incredibly prevalent. The Contact Lens Risk Survey was completed by approximately 1,000 contact lens wearers, and around 99% of respondents reported at least one behavior associated with an increased risk of eye infections.

“Good vision contributes to overall wellbeing and independence for people of all ages, so it’s important not to cut corners on healthy contact lens wear and care,” reports CDC Medical Epidemiologist Dr. Jennifer Cope. “We are finding that many wearers are unclear about how to properly wear and care for contact lenses.”

The following figures illustrate how prevalent some risky behaviors were among survey respondents:

Napping while wearing contact lenses – 87.1%
Showering while wearing contact lenses – 84.9%
Not replacing contact lens cases as frequently as recommended – 82.3%
Swimming while wearing contact lenses – 61.0%
“Topping off” contact lens solution – 55.1%
Sleeping in contact lenses overnight – 50.2%.
“Nearly one third of all wearers reported ever having experienced a contact lens-related red or painful eye that required a doctor’s visit,” the researchers write.

Considering how common contact lenses have become, the figures produced by the CDC’s study are significant, illustrating just how important it is that people become more aware of how contact lenses should be used and the impact bad practice can have on health.

The health problems that can be caused by risky contact lens behaviors may be enough to put some people off wearing them. However, there are a number of other benefits that specific types of contact lenses can provide that no other devices are able to.

Contact lens designs have become more sophisticated over time. While original products may have only been able to correct nearsightedness (myopia) and longsightedness, newer models of lens can be used to treat and monitor additional conditions that affect the eyes.

Orthokeratology, also known as Ortho-K, is a PC clear lens fitting procedure that offers a temporary degree of vision correction by changing the curvature of the cornea to improve its ability to focus on objects.

Altering the cornea’s curvature is achieved through the use of specially designed rigid contact lenses that are typically worn overnight. Ortho-K lenses are most commonly used to correct myopia.

Some people wear multifocal glasses because they have a condition known as presbyopia, whereby the eye’s ability to focus on nearby objects is lost. However, the condition can also be treated with multifocal contact lenses.

There are two main designs for these types of lenses. Alternating vision lenses have two distinct areas for short- and long-distance prescriptions. The pupil alternates between the two different prescriptions as the wearer’s gaze shifts up or down.

Simultaneous vision lenses involve the pupil looking through short- and long-distance prescriptions simultaneously. The two prescriptions can either be laid out in alternating concentric rings or blended together across the lens.

Presbyopia is one condition that a “smart lens” being developed by Google and Novartis should hopefully address. Last year, Novartis suggested that the use of technology such as noninvasive sensors and microchips contained within the lens could “provide accommodative vision correction” to restore the eye’s ability to focus.

Their smart lens might also provide benefit outside of visual health. Novartis stated that such a lens could provide a continuous measurement of glucose levels in diabetic patients and deliver this information to a mobile device using a wireless connection.

“We are looking forward to working with Google to bring together their advanced technology and our extensive knowledge of biology to meet unmet medical needs,” announced Novartis CEO Joseph Jimenez. “This is a key step for us to go beyond the confines of traditional disease management, starting with the eye.”

One of the most frequently repeated recommendations concerning contact lenses is that wearers should always follow the advice of their eye care providers. Unlike glasses, contact lenses are in direct contact with an opening into the human body, and as such there are far more things that could go wrong from a health perspective.

When used correctly, contact lenses can have a transformative effect on the wearer’s quality of life. The same can be said for when they are used incorrectly, only for wholly different and more unpleasant reasons.

It does not take much time to wash hands before handling lenses, to remove them before showering or to clean out a storage case properly, and yet by skipping these simple steps, thousands of contact lens wearers are putting their vision at risk. Follow the advice of eye care providers and vision can be protected for years to come.

Previously, Medical News Today reported on a study that suggested wearing contact lenses may alter the microbiome of the eye.

Once an optometrist has confirmed a diagnosis of myopia, several treatments are available. Speaking to an optometrist can help a person decide on the best option for them.

The sections below will discuss some of these treatment options in more detail.

Glasses and contact lenses
Glasses and contact lenses are the most common treatment options for myopia. An optometrist will order custom lenses that have the right prescription for that person. These will fit into the frame of the glasses and correct any nearsightedness.

Contact lenses are clear discs that sit on the surface of the eye. Like glasses, contact lenses are also customizable for different prescriptions.

Many people who do not like the look or feel of glasses will choose to have contact lenses, as they are a lot smaller and harder to notice. However, it is necessary to change and clean them regularly.

Orthokeratology
People with mild forms of myopia may benefit from a nonsurgical process called orthokeratology, or corneal refractive therapy. This treatment involves wearing a series of rigid contact lenses to reshape the cornea.

These lenses put pressure on the cornea to flatten it. This, in turn, changes how light focuses as it enters the eye. People tend to wear these contact lenses while sleeping.

This process can help people experience clear vision temporarily. However, it also carries a risk of eye infections.

Surgery
There are a couple of different types of surgery available to people who would rather not wear glasses, who want a more permanent solution, or who have severe forms of myopia.

One form of surgery is laser surgery, wherein an eye doctor will use a powerful beam of light to change the shape of the cornea.

Laser surgery adjusts how the eye focuses light, meaning that images that were once blurry should now be clear.

The surgery takes around 10 minutes per eye. This option can be expensive, but it is usually painless. Vision should return to normal within a day or so of the surgery.

However, it is normal to have occasional blurred vision or dry eyes for weeks or months afterward. Attending follow-up appointments after this procedure is important to make sure that the eyes are healing properly.

Other forms of surgery can involve placing a PC photochromic blue cut lens inside the eye, either in front of the person’s lens or in place of it. Eye doctors tend to recommend this form of surgery for more severe forms of myopia.

Prevention
Given that myopia has genetic links, it can be hard to prevent in people who have a history of nearsightedness in their family.

Spending time outside, in the daylight, could help lower the progression of myopia. Making sure not to spend too much time doing up-close work, such as reading or working on a computer, can also help.

Outlook
In most cases, myopia does not cause any further health problems. There are a range of treatments available that allow people to experience no symptoms of the condition in their daily lives.

For those who have more severe forms of myopia, it is important that they tell their optometrist about any changes in their vision. Without treatment, they could be at risk of developing additional eye problems, or even vision loss.

There is evidence that both genes and environmental factors, such as spending less time outdoors and more time indoors reading and using computers, can increase the risk of myopia. Before this study, however, it was not clear what the underlying molecular mechanisms were.

One way to observe the biological development of myopia or hyperopia is by altering the focal length of the eye in laboratory animals. Specialists can do this by placing a lens in front of the eye for several weeks.

Depending on the type of lens, the exposure causes the eye to develop to a length that is either too long or too short.

The scientists used this method in marmosets to study the development of myopia and hyperopia. They placed a PC photochromic lens in front of only one eye for up to 5 weeks and let the other eye develop normally for comparison.

Starting your own plants from seed will often give you healthier plants at a lower cost.  If you want to start seeds in bulk, you may want to consider a seed tray to help with germination.

So, what is a seed tray?  A seed tray is a container used to sow multiple seeds at once.  After seed germination, seedlings grow in the seedling tray until they are large enough for transplant.  A single seed tray can hold anywhere from 6 seeds to over 1000 seeds!

Of course, when choosing a seed tray, there are lots of options for the material, the type of tray, and the number of cells.

In this article, we’ll talk about seed trays and the options that are available.  We’ll also get into how to use seed trays and how to water the seeds and seedlings.

Let’s get going.

What Is A Seed Tray?
A seed tray is a container that is used to plant multiple seeds at once.  A seed tray is sometimes called a seed starting tray.
 A seed tray allows you to plant many seeds together in one container.  This makes it much easier to water them and transport them.

After the seeds germinate, the seed tray holds seedlings as they grow, until they are ready for transplant outdoors or into larger containers.
There are a few different types of seed trays, including:

Mesh seed tray – a mesh seed tray allows water to drain out easily.  A mesh seed tray is best for holding multiple individual containers (pots).  A drawback is that the holes in a mesh seed tray are too large to hold soil without it falling through or washing away when watered. You can find mesh seed trays from Johnny’s Selected Seeds.
Solid seed tray with drainage holes – a solid seed tray with drainage holes allows for adequate drainage, but allows soil to stay moist enough for seed germination.  A solid seed tray with drainage holes is best for planting multiple seeds together in one place.  A drawback is that the seedlings do not have individual cells, so their roots can get tangled together as they grow. You can find solid seed trays with drainage holes from Johnny’s Selected Seeds.
Solid seed tray without drainage holes (leak proof seed tray) – a solid seed tray without drainage holes does not allow for any drainage.  A solid seed tray without drainage holes is best for holding a cell flat (also called a plug flat).  Since it holds water, it can be used to catch excess water from watering seeds, or it can be used to water from below (more detail on this later). You can find cell seed trays without drainage holes from Johnny’s Selected Seeds.

Another interesting option is this seed flat with 20 rows from Johnny’s Selected Seeds. Instead of separate cells, there are separate rows to keep different plant varieties from getting mixed up.

If you decide to use a cell flat for seed germination, each cell should have its own drainage hole.  The tray below the cell flat should be solid without holes if you want to water the seeds from below.

The main problem of adapting the SRI techniques is high labor requirements for manual and lacking of mechanized system for planting single seedling in the field. The existing seedling preparation methods remain challenging among SRI practitioners due to traumatic condition. This study was intended to create modern techniques for increasing the quality and transplanting potentials to improve seedling preparation and reduce transplanting shock. It involved development of rectangular tray having 924 square growing cavities with sliding base to facilitate seedling transfer. Seed selection was conducted and 100% germination was obtained from the sunken MR219 seeds collected in 80 g/L of NaCl solution. SRI-tray seeding was 100% placed into cavities with SRI-seed picker at 150 g/L of tapioca solution. Two different media (Soil + Burnt husk (1:1) as M1 and Soil + Compost (1:1) as M2) were used to evaluate the growth performances for 10 days. The measured parameters (Seedling Height (SH), Leaf Length (LL), Leaf Number (LN), Root Length (RL) and Loosening Index (LI)) were compared between SRI-tray and conventional ones. The SAS revealed that M2 on SRI-tray had the highest significant values for SH, LL, RL and LI with the mean values of 155.6, 109.3, 89.3 and 75 sec when compared with conventional tray which had 125, 91 and 52 mm with no LI, respectively. The seed rate, nursery area and seedling age to support one hectare of planting area were found as 5.34 kg, 36 m2 and 8-10 days on SRI-tray against 15-50 kg, 250-500 m2 and 12-30 days on conventional practices.

The more pellets that are placed in the mould, the denser and stronger the seedling tray with lids.
In cheaper trays, there tend to be slightly bigger gaps between the expanded pellets, and fine plant roots can enter these, making it difficult to pull out the plants.

Damping off organisms can also lurk in these small spaces, and the growing plants can become infected and die. One of the Pythium species (fungus-type pathogens) is usually the main culprit, but it’s not the only one.

I have used horse manure compost as a medium for 23 years and have never had damping off problems. This may be because the medium is a rich source of beneficial organisms, which suppress development of pathogens. I also never get powdery mildew on Brassica seedlings.

Once the pathogen has appeared, the trays must be sterilised, or the problem will keep cropping up and possibly cause major losses.

The most effective way of sterilising trays is in a heat chamber. To save cost and effort, some growers wait until damping off starts before using heat sterilising.

Another solution is to use a commercial dip containing copper; this will also reduce the penetration of roots into the fine gaps in the polystyrene.

If you are a small grower, you can use a simple, home-made steriliser such as bleach mixed with water at a 10% solution, or hydrogen peroxide at 3% concentration. Leave the trays suspended in the solution for 20 minutes, then rinse and dry them.

The ideal sealant
One of the most effective ways of treating seedling trays is to dip them in a water-based roof paint when they are still new.

Obtain a flat receptacle slightly larger than the tray and dilute the paint with 10% water. Push the tray face down into the paint until the paint reaches the drainage holes. Lift and allow the excess paint to drip back into the tray, then place it face-up to dry. (It’s unnecessary to paint the base.) You should be able to coat about 10 trays per litre.

Some farmers are put off by the price of paint, but this treatment is well worth the cost: not only does it extend the life of the rice seedling tray by many years, but it seals the fine gaps in the polystyrene.

This reduces the risk of pathogens lurking in these crevices and also makes it much easier to pull out the seedlings.

Roof paints come in many colours, so you can use different colours for different years to keep track of the lifespan of each batch of styrofoam seed trays. There are often specials on roof paints and you can take advantage of these to cut the costs of the treatment.
Biodegradable plastics have been widely introduced into agricultural production, but their impacts on the soil ecosystem remain unclear. The present study investigated the impacts of a biodegradable seedling tray (BST) on the microbial communities in paddy soils. A 110-day rice culture experiment was conducted with three different paddy soils developed from black soil (BS, black chernozem soil), chao soil (CS, Fluvo-aquic) and red soil (RS, Alfisols) and three application rates of BST (0, 0.02 and 0.2 g kg−1). Soil phthalic acid ester (PAE) concentrations, physicochemical properties and enzyme activities were determined to evaluate the influence of BSTs on soil quality. 16S high-throughput sequencing was used to study bacterial community composition and the Biolog EcoPlate™ test was used to profile microbial activity and community function. Results show that the application of BSTs did not markedly affect soil quality, and the potential release of PAEs from BSTs was negligible. Interestingly, the microbial community was affected by BSTs in a soil-dependent and time-dependent pattern. The microbial community in RS was not significantly influenced by BSTs. Relative abundances of some predominant genera in BS (e.g. norank_f__BSV40) and CS (e.g. Norank_f__Nitrosomonadaceae) were significantly influenced by BSTs, and db-RDA results show that community composition in BS and CS was shaped mainly by BSTs. Community level profiling shows that BSTs significantly increased microbial activity and decreased functional diversity in BS after 55 days, but the impacts disappeared after 110 days. The results contribute to the knowledge of how biodegradable plastics influence microbial communities in paddy fields and provide information relevant to the practical use of BSTs under field condition.
This experiment investigated the effect of different plug-tray cell designs on root development of red maple (Acer rubrum), red oak (Quercus rubra), and quaking aspen (Populus tremuloides) seedlings. In April of 2015, seeds of each species were sown into three plug trays with different substrate volumes and grown for 17 weeks. Two trays had permeable walls for air-pruning, one with vertical ribs and one without. The third tray had impermeable plastic cell walls. Harvested seedlings were analyzed for root dry weight, length, volume, surface area and number of deflected roots. Root length per volume was highest in the impermeable-walled tray for red maple and quaking aspen. The total numbers of deflected root systems were higher for all species in the impermeable-walled tray. Seedlings grown in the air-pruning trays had smaller proportions of deflected root masses. Greater substrate volume did not influence root deflection development. The air-pruning tray without vertical ribs had the lowest total number of root masses with misdirected roots and lower proportions of root masses with misdirected roots for all species. These results indicate that improved root architecture in root-air pruning tray designs is achievable in tree propagation; however, vertical plastic structures in air-pruning trays can still cause root deflections.

One particular decor element that has taken root – and is quickly gaining ground in the region this year – is the crescent tree.

Chances are you’ve come across it yourself: the artificial tree comes in a number of sizes and colours, with its defining feature being its distinct crescent moon shape.

With its Instagram-friendly appearance, it has blown up online under different names – moon tree, green ramadan eid crecsent moon tree, Ramadan tree and even Eid tree – as more families take to them. A search for #RamadanTree on Instagram turns up more than 1,000 posts, while one for #EidTree yields over 1,500; impressive since three years ago, they didn’t really exist.

So how did it all begin? It all seems to have started in Michigan, in the US, where resident Samar Baydoun Bazzi decided to mark the holy month with some festive cheer. As a mother, she wanted to create a special experience for her daughter, so she began incorporating Islamic-themed art into the home. When that wasn’t enough, she tried a Christmas tree, but that only confused her child further, she told local media.

That is how Bazzi ended up taking things into her own hands – by creating Ramadan trees in the shape of a crescent moon as a tribute to Islam. As the pictures of the trees circulated online, she started getting orders and the trend just picked up from there.

How did trend reach the UAE?
The crescent-shaped tree is making its way across to the UAE, too. Zahirah Marty, founder of brand development agency Think Liquorice, purchased one in 2020 through Amazon, but she found it quite difficult to source one at the time, and options were limited.

Today, however, it's easier, as a number of brands have starting selling them.

Crate & Barrel, which introduced the tree in 2020, saw sales of the crescent tree soar this year. The hugely popular item can be bought item both online and in-store, for Dh400.

Why get a crescent tree?
UAE resident and mum-of-four Taghred Chandab, who bought one before Ramadan from Kibsons, says it worked as a great way to start a conversation with little ones about Islam and Ramadan.

“We like to decorate for Ramadan and Eid, to give the children a sense of excitement around both the holy month and Eid. My youngest is 5 and she has asked over the years if we could have a Christmas tree at Christmas, but as Muslims we didn't feel this was appropriate as it didn't reflect our beliefs.

"She was really excited when the white ramadan eid crecsent moon tree arrived and we explained to her why the moon was important in Islam, particularly around Ramadan and Eid. She feels the spirit now. Sometimes kids need visual aids to understand."

When Marty posted a picture of her tree on social media last year, she received many queries from other parents, also looking for a way to “bring the month to life for their children and make it something tangible and memorable”.

"Growing up, we didn't have anything like this," she tells The National. "There weren't decorations and lights. At best we shared plates of food or dates with neighbours and family and waited for Eid; for a day of family and food. We did a little less that month, and besides the wave of energy at iftar, it was a pretty non-eventful month from a child's perspective.

“I want Ramadan to be a month-long celebration of who we are, and time at home together, and most importantly I want to create new traditions for my family based on our diversity and mixed cultural background, because that’s a part of our identity.

"It is a month to reflect, and reconnect with ourselves, our home, our family, our creator and I want that to be done in a lively and festive space. Having that centrepiece is a symbolic display of that for me."

Marty says she makes setting up the tree an educational and fun experience for her son Noah, who loves it, too. “While we decorate it, we chat about why it’s a moon and not a tree, why we have it out, what fasting means and how he has so much to look forward to with Eid.

“I want Noah to fall in love with his faith, and all that it comes with. We live in a very challenging world, and children today won’t accept things ‘because we say so’. I want my son to view religion as the beautiful part of his world it is from a young age, and creating reasons to celebrate, decorate and bring joy is how I choose to do it. Everything else will follow."

A response to criticism
Despite its popularity, the trend is not without its criticism. A cursory search online will find comments about it copying western traditions, while others believe it can be ostentatious.

“In any area of life there will always be critics, and I respect that as humans we will differ in our opinions," says Marty. "I prefer to focus on my intention to create happy, celebratory moments for my family as a medium of education, and a way of carving out our space with our circumstances.

“If a decorated moon sparks joy in my toddler to look forward to the month of Ramadan, ask me questions, and open his mind and heart to the lessons, stories and memories, then I’ve achieved my goal.”

How to decorate a Ramadan tree:
Some trees come pre-decorated, but if you prefer to decorate the gold ramadan eid crecsent moon tree together with your family, there are options in the UAE.

Marty recommends Daiso as a place where one can get a range of lights in the shapes of mosques, stars and moons. She drapes her family Ramadan tree with lights, camels and even baubles.

“I grew up with a childhood tradition of new Eid pyjamas and either money or gifts. I keep that tradition in our home. The silver ramadan eid crecsent moon tree is a place we have all this sitting until the night before Eid, which adds to the excitement of Eid day,” she says.

Other places where one can get Eid and Ramadan decorations, as well as trees, include Amazon, Kibsons and noon.com.
DEARBORN — Celebrating Ramadan in the U.S. doesn’t come as naturally as it does in Muslim-majority countries. From fasting during long summer days to lackluster holiday cheer and enduring anti-Muslim sentiments, Muslim Americans have to try just a little harder throughout Islam’s holiest month.

Samar Baydoun Bazzi, a 29-year-old Dearborn resident and nursing student, knows that all too well and is trying to change that— one crecsent tree decorations at a time.

Bazzi told The AANews she remembers feeling like the “odd one out” growing up as a Muslim in Michigan, especially after she began wearing the hijab. During Muslim holidays, she rarely would feel any enthusiasm as gatherings were mostly isolated to family and close friends. Her home would only light up with decorations during Christmas.

Although simple Ramadan-related decorations adorn some properties in Dearborn, Bazzi said she wants to bring a little extra Ramadan spirit to a city that’s home to one of the most concentrated Arab and Muslim American communities and one of the largest mosques in the nation.

“People can get more creative,” she said.

The project, now in its fourth year and selling nationwide, began when Bazzi’s daughter, 4-years-old at the time, thought it was Christmas when she put up a tree along with other banners and crafts, in preperation for Ramadan.

That same day, Bazzi said she took the tree apart and rearranged it in the shape of a crescent moon, a widely-recognized symbol in Islam.

“I wanted her to be excited about her own religion and holiday,” she said about her daughter.

Bazzi, who crafts the trees by hand in her basement, said she quickly learned that many Muslim households face the same obstacles and people wished they’d had such trees in their childhoods.

“The parents want their kids to feel like their own holiday is the most amazing time of the year,” Bazzi said. “It’s a time when they’re supposed to be closer to God, to pray and fast; we want them to fall in the love with the whole process.”

Bazzi said her intention was not to blend Anglo-Christian and Pagan traditions with Islamic ones by using a Christmas tree and that she initially only used a tree because that’s what she had available.

“It really makes no difference to me,” she said. “It doesn’t look like a Christmas tree anymore.”

At a time when political tensions are high and bigoted rhetoric is rampant, Bazzi said her goal is to ensure Muslim Americans, especially the youth, can be unabashedly proud and more openly celebrate their faith.

It takes her about five hours to make each tree. The six-foot-and-eight-inch-tall trees are available in white and green and include lights and a hanging star. They’re being sold nationwide, with requests for them coming from around the world.

Bazzi said the Ramadan Trees have garnered enough interest for a wait list to fill up, forcing her to stop accepting orders this year.

She said she hopes to partner with a manufacturer and expand the project into a large-scale business. 
For Samar Baydoun Bazzi, the Ramadan Tree grew out of a desire to mark the Islamic holy month with festive cheer.

Growing up as a Muslim in the U.S., Baydoun Bazzi, 29, of Dearborn said she noticed a lack of decorations during the month-long holiday, which Muslims observe by fasting from sunrise to sundown to commemorate the revelation of the Quran to the prophet Muhammad.

“Obviously, Ramadan’s important,” Baydoun Bazzi said. “You gotta pray and fast, and you want to become closer to your creator. But I never as a kid felt like there was any decorations or like a celebration. I wanted something exciting.”

When she became a mother, she decided to take matters into her own hands and create the kind of Ramadan experience she wished for as a child.
She began by decorating her west Dearborn home with Islamic-themed art, like acrylic paintings of Arabic calligraphy and a cardboard model of a mosque.

It wasn’t enough.

So in 2014, she said, she decided to put up a Christmas tree.

It didn't last long.

“Oh, Christmas!” Baydoun Bazzi remembers her daughter Zahraa, then 4 years old, shouting.

“I knew that it was a mistake,” Baydoun Bazzi said of her decision. “So I looked at my tree and decided to take it apart.”

That’s when the Ramadan Tree first took root. 

The researchers expressed concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products.

The researchers conducted tests using an inflatable beach ball, a pair of swimming armbands and two bathing rings they bought off the shelf from local stores and online suppliers in Germany.(Shutterstock)
HEALTH
Are stinky inflatable kids' toys putting your kids at risk? Here’s what a study found
The researchers expressed concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products.
Washington D.C. | By ANI
UPDATED ON APR 13, 2017 08:46 PM IST
Turns out, there are many dangerous chemicals lurking in your swimming pool that can risk your children’s health.

Inflatable sprinkler and swimming aids, like bathing rings and arm bands, often have a distinctive smell which could indicate that they contain a range of potentially hazardous substances.

Some of these compounds, which include carbonyl compounds, cyclohexanone, phenol and isophorone, might be critical when present in higher concentrations in children’s toys, said authors Christoph Wiedmer and Andrea Buettner.

Lead author Wiedmer from Fraunhofer Institute for Process Engineering and Packaging IVV in Germany and his team conducted tests using an inflatable pool, a pair of swimming armbands and two bathing rings they bought off the shelf from local stores and online suppliers in Germany.

A small piece of material from each sample was analysed using a variety of material analysis techniques, including one that takes infrared measurements, and it was concluded that the inflatable objects were all made from polyvinyl chloride (PVC).

The researchers then investigated the molecular make-up of the distinctive smells arising from the pool toys. They extracted detectable odours from each sample using solvent extraction and high vacuum distillation methods, and then identified the main odorants using a combination of sensory and common analytical approaches.

Between 32 and 46 odours were detected in each sample, of which up to thirteen were quite intense. The majority of these odorants were identified and among these were several fatty smelling mono- or di-unsaturated carbonyl compounds and their epoxidised derivatives, but also odouractive organic solvents such as cyclohexanone, isophorone, and phenol.

As part of the study, a panel of trained volunteers sniffed each product, and ascribed common odour attributes to these. They also rated the intensity of each odour, and had to guess whether these could be hazardous. Three of the products reminded the panellists of almonds, plastic and rubber, while the fourth more pungent one reminded them of glue and nail polish.

Wiedmer expressed his concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products. Cyclohexanone can be harmful if inhaled, phenol is known to be acutely toxic and to presumably have mutagenic potential and isophorone is a category 2 carcinogen, which means that this is a suspect substance in the development of cancer in humans.

“A range of these substances are not yet resolved in their chemical structures. Likewise, potential negative effects on humans, such as irritation, smell nuisance, or other physiological or psychosomatic effects still need to be resolved,” said Wiedmer.

“Modern products such as toys and children’s products are sourced from a wide variety of chemical and physical manufacturing processes, and this complexity often makes it difficult for us to identify those containing contaminants and unwanted substances, and to determine their causes,” noted Wiedmer. “However, we found that in a number of cases our noses can guide us to ‘sniff out’ problematic products.”

The study appears in the journal Analytical and Bioanalytical Chemistry (ABC).
Backyards and patios have been working hard all year because of the pandemic, and this summer they can provide new ways to cool off and have fun in the water.

Whether you have a lot of space or a little, there’s gear ranging from water tables and tubs for kids to floating loungers with drink holders for adults.

One company, Minnidip, makes inflatable “adult kiddie pools” that aim to transport you to some exotic travel destination. Patterns on the Marrakesh pool reference Moroccan architectural details, while the Amalfi is a nod to the blue, yellow and white tile of the Italian coast.

“Because for me, having a pool on our urban Chicago rooftop felt like being transported to another place,” says company founder Emily Vaca. “I wanted to capture that feeling through design and pattern. “

Minnidip also offers inflatable drinks coolers and glam pool balls filled with gold confetti, among other offerings.

The only water table that lets you make waves, Little Tikes’ Island Wavemaker has a water wheel, plus cute sea creatures and a wee pirate to send paddling around the waterway or down the waterfall. Toddlers can practice their fine motor skills with Little Tikes’ Spinning Seas Water Table; small balls, a cup, a funnel and a water wheel set up the fun.

Step2’s two-sided Waterfall Discovery Wall has adjustable toggles, spinners and chutes to send the water tumbling in lots of different ways. And Lakeshore Learning’s Watch It Flow water table features three plastic logs that can be configured however you wish. Fill the logs using a hose or bucket; gates control the flow and can close up to make long tubs.

Foamo, also from the folks at Little Tikes, creates mountains of easy-to-clean-up foam when you add the nontoxic, biodegradable foam solution to water.

HOSE HAPPY

Turn on the hose and attach it to West Elm's inflatable car bed or giant shark mouth sprinklers. Fat Brain Toy’s Hydro Twist Pipeline Sprinkler has a couple of fountains, plus a bunch of wiggly worm hoses. Or hook up to BigMouth’s giant 6-foot-high unicorn, who shoots water out of her horn. There’s a ginormous ape, giraffe, dinosaur and giraffe here as well.

SWIM AND PADDLE

Giant inflatable water wheels let you find your inner hamster. You can find ones online for toddlers, while Wow Watersports has a grownup version they call the Aqua Treadmill.

Don’t forget the family pets; a nonporous, puncture-resistant floating dog bed at Frontgate comes in a bunch of colors and three sizes.

Chewy has ZippyPaws Floaterz sturdy turtle-shaped water toys for dogs, as well as rope-handled bumpers and a variety of floating balls.

A hard-sided kiddie pool can be a good non-inflatable option for cooling off; just hose it out and stow away. Other pluses: The doggos will also have fun splashing around in it, and it makes a great sand or snow play zone in colder weather. The Sun Squad Wading Kiddie Pool is inexpensive and has an embossed bottom, so it’s less slippery.

SLIDE AND RIDE

A basic heavy-duty plastic water slide or “slip and slide” can be set up in most backyards; if yours doesn’t come with an attached barrier at the bottom, make sure to put something soft there.

Studio 21 Graphix’s slide has a crash pad at the finish line, plus two lanes for racing and a sprinkler curtain to pass thru on the way down. Wow Watersports’ Strike Zone Water Slide is 25-by-6 feet of slipperiness; zigzag sprinkler patterns assure a wet ride, fat pontoons on either side keep riders inside, and two sleds are included. Got a really long yard? Get two; they can be interconnected.

If you’ve got lots of space, consider Costway’s inflatable Bounce House and Water Slide, with a bounce area, water gun, two slides, a basketball hoop and several balls. It comes with a storage bag for easy transport.

POOL STYLE

Marisa Issa of Los Angeles says her family’s favorite pool games are corn hole and a floating basketball hoop, but her favorite is a floating mat from Frontgate “that only mom can use,” she says. The sleek, minimalist white float has a headrest, and is made of marine-grade dense foam, suitable for chlorine or saltwater pools.

If you prefer sitting up a little, Frontgate’s got a floating armchair with attached ottoman. Choose from aqua, blue or flamingo pink. Or splash out on a full-size pool chaise kitted out with drink holders.

Want to hang out with a handful of friends in a backyard pool? Funboy has a 9-foot-wide floating metallic crown with drink holders. Or lounge luxuriously in the company’s Bali Cabana Lounger, with a curved integrated shade, a tropical leaf print, cup holders and handy grab ropes.

BigMouth has some food-related inflatables like a giant ice pop, pizza slice, donut, watermelon slice, cheeseburger and taco.
At first, glance, laying on an inflatable toy in shallow water seems pretty safe. After all, the water isn't deep, and there is a floating toy right there. Recently, a family's trip to the beach in Nova Scotia proved to be a harrowing reminder of why this is not the case. In August, two 5-year-olds played in shallow water – one in an inflatable ring, the other on an inflatable roller. Because the girls were in shallow water, their caregiver assumed the inflatable toys were enough. It wasn't until the girls began to drift away from that the complete danger of the situation became clear.

Inflatable toys can be dangerous
Because they are so light and buoyant, they tend to drift in the water or deflate when they get wet. That's when it's a problem. Kids don't know when their toys are deflated and cannot compensate when they're in the water. They can get trapped in the holes or strangle. When the girls got stuck, their caregiver did the right thing by calling for help. First responders rescued the girls and took them to the hospital to be treated for their injuries. While it's infrequent that inflatable toys are the source of injury to kids, it's good to know that they can pose a hazard. The numbers aren't obvious, but it seems that they're responsible for 1 in every 100 boating-related deaths in the U.S. and are one of the leading causes of drowning for children aged 4-6.

Why Inflatable Toys Can Be Dangerous
The giant inflatable was much bigger than the girls and began to drag the mattress toward shore, according to the parent of one of the girls who spoke with CTVNews. However, the inflatable ring wasn't nearly as big or heavy and was drifting with the current. The girls eventually lost hold of both and drifted a considerable distance. The girls' parents rushed to the scene and tried to retrieve their children, but the current was too firm, and the military eventually rescued them. The girls were found to be unharmed. Since this incident, many parents have expressed concerns about the safety of inflatable toys.