A gear pump is a type of positive displacement (PD) pump. Gear pumps use the actions of rotating cogs or gears to transfer fluids.  The rotating gears develop a liquid seal with the pump casing and create a vacuum at the pump inlet.  Fluid, drawn into the pump, is enclosed within the cavities of the rotating gears and transferred to the discharge.  A gear pump delivers a smooth pulse-free flow proportional to the rotational speed of its gears.

There are two basic designs of gear pump: internal and external (Figure 1).  An internal gear pump has two interlocking gears of different sizes with one rotating inside the other.  An external gear pump consists of two identical, interlocking gears supported by separate shafts.  Generally, one gear is driven by a motor and this drives the other gear (the idler).  In some cases, both shafts may be driven by motors.  The shafts are supported by bearings on each side of the casing.

This article describes plastic gear pump in more detail.
There are three stages in an internal gear pump’s working cycle: filling, transfer and delivery (Figure 2).

As the gears come out of mesh on the inlet side of the pump, they create an expanded volume.  Liquid flows into the cavities and is trapped by the gear teeth as the gears continue to rotate against the pump casing.

The trapped fluid is moved from the inlet, to the discharge, around the casing.

As the teeth of the gears become interlocked on the discharge side of the pump, the volume is reduced and the fluid is forced out under pressure.

No fluid is transferred back through the centre, between the gears, because they are interlocked.  Close tolerances between the gears and the casing allow the pump to develop suction at the inlet and prevent fluid from leaking back from the discharge side (although leakage is more likely with low viscosity liquids).

External gear pump designs can utilise spur, helical or herringbone gears (Figure 3).  A helical gear design can reduce pump noise and vibration because the teeth engage and disengage gradually throughout the rotation.  However, it is important to balance axial forces resulting from the helical gear teeth and this can be achieved by mounting two sets of ‘mirrored’ helical gears together or by using a v-shaped, herringbone pattern.  With this design, the axial forces produced by each half of the gear cancel out.  Spur gears have the advantage that they can be run at very high speed and are easier to manufacture.

Gear pumps are compact and simple with a limited number of moving parts. They are unable to match the pressure generated by reciprocating pumps or the flow rates of centrifugal pumps but offer higher pressures and throughputs than vane or lobe pumps. External gear pumps are particularly suited for pumping water, polymers, fuels and chemical additives. Small external gear pumps usually operate at up to 3500 rpm and larger models, with helical or herringbone gears, can operate at speeds up to 700 rpm. External gear pumps have close tolerances and shaft support on both sides of the gears. This allows them to run at up to 7250 psi (500 bar), making them well suited for use in hydraulic power applications.

Since output is directly proportional to speed and is a smooth pulse-free flow, external gear pumps are commonly used for metering and blending operations as the metering is continuous and the output is easy to monitor. The low internal volume provides for a reliable measure of liquid passing through a pump and hence accurate flow control. They are also used extensively in engines and gearboxes to circulate lubrication oil. External gear pumps can also be used in hydraulic power applications, typically in vehicles, lifting machinery and mobile plant equipment. Driving a gear pump in reverse, using oil pumped from elsewhere in a system (normally by a tandem pump in the engine), creates a motor. This is particularly useful to provide power in areas where electrical equipment is bulky, costly or inconvenient. Tractors, for example, rely on engine-driven external gear pumps to power their services.

External gear pumps can be engineered to handle aggressive liquids. While they are commonly made from cast iron or stainless steel, new alloys and composites allow the pumps to handle corrosive liquids such as sulphuric acid, sodium hypochlorite, ferric chloride and sodium hydroxide.

What are the limitations of a gear pump?
External gear pumps are self-priming and can dry-lift although their priming characteristics improve if the gears are wetted.  The gears need to be lubricated by the pumped fluid and should not be run dry for prolonged periods.  Some gear pump designs can be run in either direction so the same pump can be used to load and unload a vessel, for example.

The close tolerances between the gears and casing mean that these types of pump are susceptible to wear particularly when used with abrasive fluids or feeds containing entrained solids. External gear pumps have four bearings in the pumped medium, and tight tolerances, so are less suited to handling abrasive fluids.  For these applications, universal gear pump are more robust having only one bearing (sometimes two) running in the fluid.  A gear pump should always have a strainer installed on the suction side to protect it from large, potentially damaging, solids.

Generally, if the pump is expected to handle abrasive solids it is advisable to select a pump with a higher capacity so it can be operated at lower speeds to reduce wear.  However, it should be borne in mind that the volumetric efficiency of a gear pump is reduced at lower speeds and flow rates.  A gear pump should not be operated too far from its recommended speed.

For high temperature applications, it is important to ensure that the operating temperature range is compatible with the pump specification.  Thermal expansion of the casing and gears reduces clearances within a pump and this can also lead to increased wear, and in extreme cases, pump failure.

Despite the best precautions, gear pumps generally succumb to wear of the gears, casing and bearings over time.  As clearances increase, there is a gradual reduction in efficiency and increase in flow slip: leakage of the pumped fluid from the discharge back to the suction side.  Flow slip is proportional to the cube of the clearances between the cog teeth and casing so, in practice, wear has a small effect until a critical point is reached, from which performance degrades rapidly.

Gear pumps continue to pump against a back pressure and, if subjected to a downstream blockage will continue to pressurise the system until the pump, pipework or other equipment fails.  Although most gear pumps are equipped with relief valves for this reason, it is always advisable to fit relief valves elsewhere in the system to protect downstream equipment.

The high speeds and tight clearances of external gear pumps make them unsuitable for shear-sensitive liquids such as foodstuffs, paint and soaps.  Internal gear pumps, operating at lower speed, are generally preferred for these applications.

What are the main applications for gear pumps?
External gear pumps are commonly used for pumping water, light oils, chemical additives, resins or solvents.  They are preferred in any application where accurate dosing is required such as fuels, polymers or chemical additives.  The output of a gear pump is not greatly affected by pressure so they also tend to be preferred in any situation where the supply is irregular.


Summary
An external gear pump moves a fluid by repeatedly enclosing a fixed volume within interlocking gears, transferring it mechanically to deliver a smooth pulse-free flow proportional to the rotational speed of its gears.

External gear pumps are commonly used for pumping water, light oils, chemical additives, resins or solvents.  They are preferred in applications where accurate dosing or high pressure output is required.  External gear pumps are capable of sustaining high pressures.  The tight tolerances, multiple bearings and high speed operation make them less suited to high viscosity fluids or any abrasive medium or feed with entrained solids.
External-gear pumps are rotary, positive displacement machines capable of handling thin and thick fluids in both pumping and metering applications. Distinct from internal-gear pumps which use “gear-within-a-gear” principles, external-gear pumps use pairs of gears mounted on individual shafts. They are described here along with a discussion of their operation and common applications. For information on other pumps, please see our Pumps Buyers Guide.

Spur gear pumps
Spur gear pumps use pairs of counter-rotating toothed cylinders to move fluid between low-pressure intakes and high-pressure outlets. Fluid is trapped in pockets formed between gear teeth and the pump body until the rotating gear pairs bring individual elements back into mesh. The decreasing volume of the meshing gears forces the fluid out through the discharge port. A relatively large number of teeth minimizes leakage as the gear teeth sweep past the pump casing.

Spur gear pumps can be noisy due to a certain amount of fluid becoming trapped in the clearances between meshing teeth. Sometimes discharge pockets are added to counteract this tendency.

Spur gear pumps are often fitted with sleeve bearings or bushings which are lubricated by the fluid itself—usually oil. Other fluids that lack oil’s lubricity generally demand more stringent pump designs, including locating bearings outside of the wetted cavities and providing appropriate seals. Dry-running bearings are sometimes used. The use of simply-supported shafts (as opposed to cantilevered arrangements seen in many internal gear designs) makes for a robust pump assembly capable of handling very thick liquids, such as tar, without concern for shaft deflection.

Helical gear pumps
Similar to the spur gear pump, the helical gear pump uses a pair of single- or double-helical (herringbone) gears. Helical gears run quieter than spur gears but develop thrust loads which herringbone gears are intended to counteract. These designs are often used to move larger volumes than spur gear pumps. Helical gears produce fewer pulsations than stainless gear pump as the meshing of teeth is more gradual compared with spur-gear designs. Helix angles run between 15 and 30°.

Both the helical and herringbone gear pumps eliminate the problem of trapping fluid in the mesh. These designs can introduce leakage losses where the teeth mesh, however, unless very tight tooth clearances are maintained. The higher manufacturing costs associated with herringbone gear pumps must be balanced against their improved performance.

Applications
External-gear pumps can pump fluids of nearly any viscosity, but speed must normally be reduced for thicker materials. A typical helical gear pump might run at 1500 rpm to move a relatively thin fluid such as varnish but would have to drop its speed nearer to 500 rpm to pump material as thick as molasses in July.

External-gear pumps generally are unsuited for materials containing solids as these can lead to premature wear, although some manufacturers make pumps specifically for this purpose, usually through the use of hardened steel gears or gears coated with elastomer. External-gear pumps are self-priming and useful in low NPSH applications. They generally deliver a smooth, continuous flow. In theory, at least, they are bi-directional. They are available as tandem designs for supplying separate or combined fluid-power systems.

These pumps are capable of handling very hot fluids although the clearances must be closely matched to the expected temperatures to insure proper operation. Jacketed designs are available as well.

External-gear pumps see wide applications across many industries: food manufacturers use them to move thick pastes and syrups, in filter presses, etc.; petrochemical industries deploy them in high-pressure metering applications; engine makers use them for oil delivery. They are used as transfer pumps. Special designs are available for aerospace applications. Pumps for fluid power will conform to SAE bolt-hole requirements.

External-gear pumps are manufactured from a variety of materials including bronze, lead-free alloys, stainless steel, cast and ductile iron, Hastelloy, as well as from a number of non-metals.

External-gear pumps can be manufactured as sanitary designs for food, beverage, and pharmaceutical service. The gears can be overhung, supported by bearings outside the housing with a variety of seals and packings available. Access to these internal pump components through a cover plate makes sanitizing straightforward. Gears are commonly manufactured from composites of PTFE and stainless steel as well as other plastics. Close-coupled and sealless designs are available.

External gear pumps are the least costly of the various positive-displacement pumps but also the least efficient. Pressure imbalances between suction and discharge sides can promote early bearing wear, giving them somewhat short life expectancies.

One general disadvantage that all heat preservation gear pump share over some other positive-displacement pump styles – vane pumps, for instance – is their inability to provide a variable flow rate at a given input speed. Where this is a requirement, a work-around is to use drives capable of speed control, though this is not always a practical solution.

Finally, while rotary, positive-displacement pumps are capable of pumping water, their primary application is in oils and viscous liquids because of the need to keep rubbing surfaces lubricated and the difficulty in sealing very thin fluids. For most applications where water is the media, the centrifugal, or dynamic-displacement pump, has been the clearer choice.

This review highlights recent progress in the synthesis and application of vinyl ethers (VEs) as monomers for modern homo- and co-polymerization processes. VEs can be easily prepared using a number of traditional synthetic protocols including a more sustainable and straightforward manner by reacting gaseous acetylene or calcium carbide with alcohols. The remarkably tunable chemistry of VEs allows designing and obtaining polymers with well-defined structures and controllable properties. Both VE homopolymerization and copolymerization systems are considered, and specific emphasis is given to the novel initiating systems and to the methods of stereocontrol.

The composition of chlorophyll-precursor pigments, particularly the contents of diethylene glycol divinyl ether, in etiolated tissues of higher plants were determined by polyethylene-column HPLC (Y. Shioi, S. I. Beale [1987] Anal Biochem 162: 493-499), which enables the complete separation of these pigments. DV-Pchlide was ubiquitous in etiolated tissue of higher plants. From the analyses of 24 plant species belonging to 17 different families, it was shown that the concentration of DV-Pchlide was strongly dependent on the plant species and the age of the plants. The ratio of DV-Pchlide to MV-Pchlide in high DV-Pchlide plants such as cucumber and leaf mustard decreased sharply with increasing age. Levels of DV-Pchlide in Gramineae plants were considerably lower at all ages compared with those of other plants. Etiolated tissues of higher plants such as barley and corn were, therefore, good sources of MV-Pchlide. Absorption spectra of the purified MV- and DV-Pchlides in ether are presented and compared.

Both epoxides and vinyl ethers can be polymerized cationically albeit through different intermediates. However, in the case of epoxide-vinyl ether mixtures the exact mechanism of cationically initiated polymerization is unclear. Thus, although vinyl ethers can be used as reactive diluents for epoxides it is uncertain how they would affect their reactivity. Cationic photocuring of diepoxides has many industrial applications. Better understanding of the photopolymerization of epoxy-vinyl ether mixtures can lead to new applications of cationically photocured systems. In this work, photo-DSC and real-time Fourier Transform Infrared Spectroscopy (RT-FTIR) were used to study cationic photopolymerization of diepoxides and vinyl ethers. In the case of mixtures of aromatic epoxides with tri(ethylene glycol) divinyl ether, TEGDVE, photo-DSC measurements revealed a greatly reduced reactivity in comparison to the homopolymerizations and suggested the lack of copolymerization between aromatic epoxides and TEGDVE. On the other hand, for mixtures of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, ECH, with TEGDVE the results indicated high reactivity of the blends. The polymerization mechanism might include copolymerization. To examine this mechanism, mixtures of the ECH with a tri(ethylene glycol) mono-vinyl ether, TEGMVE, were studied by both photo-DSC and RT-FTIR. Principal component analysis (PCA) proved to be an efficient tool in analyzing a large matrix of the spectral data from the polymerization system. PCA was able to provide insight into the reasons for the differences among replicated experiments with the same composition ratio and supported the hypothesis of copolymerization in the ECH/TEGMVE system. Thus, blends of cycloaliphatic epoxides and vinyl ethers seem to have a great potential for applications in high-productivity industrial photopolymerization processes.

Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate, an important industrial polymer.[3]
The worldwide production capacity of 1,4-bis(vinyloxy)-butane was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000).[4] The average list price for 2008 was $1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%).[4]

It is a key ingredient in furniture glue.[5]
It can be polymerized to give polyvinyl acetate (PVA). With other monomers it can be used to prepare various copolymers such as ethylene-vinyl acetate (EVA), vinyl acetate-acrylic acid (VA/AA), polyvinyl chloride acetate (PVCA), and polyvinylpyrrolidone (Vp/Va copolymer, used in hair gels).[8] Due to the instability of the radical, attempts to control the polymerization by most "living/controlled" radical processes have proved problematic. However, RAFT (or more specifically, MADIX) polymerization offers a convenient method of controlling the synthesis of PVA by the addition of a xanthate or a dithiocarbamate chain transfer agent.
Vinyl acetate undergoes many of the reactions anticipated for an alkene and an ester. Bromine adds to give the dibromide. Hydrogen halides add to give 1-haloethyl acetates, which cannot be generated by other methods because of the non-availability of the corresponding halo-alcohols. Acetic acid adds in the presence of palladium catalysts to give ethylidene diacetate, CH3CH(OAc)2. It undergoes transesterification with a variety of carboxylic acids.[9] The alkene also undergoes Diels–Alder and 2+2 cycloadditions.

Tests suggest that vinyl acetate is of low toxicity. Oral LD50 for rats is 2920 mg/kg.[3]

On January 31, 2009, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not harmful to human health.[12] This decision under the Canadian Environmental Protection Act (CEPA) was based on new information received during the public comment period, as well as more recent information from the risk assessment conducted by the European Union.

In the context of large-scale release into the environment, it is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), under which it "does not meet toxicity criteria[,] but because of its acute lethality, high production volume [or] known risk is considered a chemical of concern". By this law, it is subject to strict reporting requirements by facilities that produce, store, or use it in quantities greater than 1000 pounds.[13]


To date, methods of quantum-chemical calculations have been increasingly developed. As a result, it is possible to estimate the geometry of molecules, calculate the stability of intermediate products and transition states. In the experimental method of calculating such results for most reactions, along with a multi-stage process, there are difficulties associated with the appearance of intermediate stages and the presence of intermediate reaction products in an extremely small time.

Radical copolymerization of polyethylene glycol maleate with Di(ethylene Glycol) monovinyl ether of monoethanol amine has been performed for the first time. Radical co- and terpolymerization of the systems polyethylene glycol maleate with acrylamide and 1,4-butanediol monovinyl ether of monoethanol amine has been studied. Molecular weight of polyethylene glycol maleate has been determined using light scattering and gel permeation chromatography. The compositions of the polymers and copolymerization constants of the studied systems have been determined. The composition of the copolymers has been found using gas chromatography. Kinetic curves show that with increasing molar fraction of acrylamide in the solution the reaction rate and swelling capacity of the copolymers increase. It has been shown that the composition of terpolymers determined experimentally differs considerably from the one calculated taking into account obtained constants of copolymerization. Deviations found are due to various intermolecular interactions in these systems. The possibility of controlling the properties of network copolymers of polyethylene glycol maleate by changing external factors has been studied. Swelling capacity of the copolymers investigated was studied using gravimetric method.
Hydrogels have been widely used for various biomedical and pharmaceutical applications due to their biocompatibility, high water content and rubbery nature, which resemble natural tissue. Polyethylene glycol (PEG) crosslinked poly(methyl diethylene glycol monovinyl ether and maleic acid) (PMVE/MA) hydrogel is widely studied as a vehicle for various types of drug delivery. It has been reported that swelling and diffusion property of hydrogel are important features for their effectiveness. Higher swelling of PMVE/MA hydrogel facilitates greater amount of drug to be delivered. However, delivery of high molecular weight drugs such as ovalbumin and bevacizumab is still a challenge with existing formulation of PMVE/MA hydrogels. This study aims to optimise PMVE/MA hydrogel formulations and determine the swelling kinetics of different hydrogel formulations.

Methods
PMVE/MA hydrogels were prepared by inducing esterification reaction with PEG. Each formulation of hydrogel consists of different concentration and molecular mass of PMVE/MA and PEG. Swelling kinetics of each formulation were studied by calculating % swelling and second order kinetic model was used to calculate the swelling rate constant (Ks) and degree of swelling at equilibrium (Seq). The effect of different foaming agents (Na2CO3 and NaHCO3) on the swelling of hydrogel was also studied.
   
Results 
Our results shows that hydrogels synthesised from higher molecular weight 15% (w/w) PMVE/MA and 7.5 % (w/w) PEG 12,000 have 2200% swelling. The swelling of hydrogel decreased with increasing concentrations of PMVE/MA and PEG. Hydrogel mixture containing PEG 12,000 with longer polymer chains resulted in better swelling compared to PEG 10,000. Meanwhile high concentration of foaming agents (up to 3% w/w) has a positive effect on hydrogel swelling. 

Conclusion 
The hydrogels formulation containing 15% (w/w) PMVE/MA and 7.5 % (w/w) PEG 12,000 in this study yielded 1.28 times greater swelling compared to previously reported formulation. It is proposed that, this hydrogel would serve as a better vehicle candidate for macromolecular drug delivery.

BAMIYAN, Afghanistan — Here is a reminder to someone with the initials A.B., who on March 8 climbed inside the cliff out of which Bamiyan’s two giant Buddhas were carved 1,500 years ago.

In a domed chamber — reached after a trek through a passageway that worms its way up the inside of the cliff face — A.B. inscribed initials and the date, as hundreds of others had in many scripts, then added a little heart.

It’s just one of the latest contributions to the destruction of the World Heritage Site of Bamiyan’s famous Buddhas.

The worst was the Taliban’s effort in March 2001, when the group blasted away at the wooden buddha statue, one 181 feet and the other 125 feet tall, which at the time were thought to be the two biggest standing Buddhas on the planet.

It took the Taliban weeks, using artillery and explosive charges, to reduce the Buddhas to thousands of fragments piled in heaps at the foot of the cliffs, outraging the world.

Since then, the degradation has continued, as Afghanistan and the international community have spent 18 years debating what to do to protect or restore the site, with still no final decision and often only one guard on duty.

One recent idea came from a wealthy Chinese couple, Janson Hu and Liyan Yu. They financed the creation of a Statue of Liberty-size 3D light projection of an artist’s view of what the larger Buddha, known as Solsol to locals, might have looked like in his prime.

The image was beamed into the niche one night in 2015; later the couple donated their $120,000 projector to the culture ministry.

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The local authorities bring it out on special occasions, but rarely, as Bamiyan has no city power supply, other than fields of low-capacity solar panels. The 3D-image projector is power-hungry and needs its own diesel generator.

Most of the time, the remains of the monument are so poorly guarded that anyone can buy a ticket ($4 for foreigners, 60 cents for Afghans), walk in and do pretty much whatever he wants. And many do.

Souvenir-hunters pluck pieces of painted stucco decorations from the network of chambers or take away chunks of fallen sandstone. Graffiti signatures, slogans, even solicitations for sex abound.

Anyone can, as A.B. did, crawl through the passageways surrounding the towering niches in the cliff, through winding staircases tunneled into the sandstone and up steps with risers double the height of modern ones, as if built for giants.

At the end of this journey, you arrive above the eastern niche, which housed the smaller Buddha, and stand on a ledge just behind where the statue’s head once was, taking in the splendid Buddha’s eye view of snow-capped mountains and the lush green valley far below.

The soft sandstone of the staircases crumbles underfoot, so that the very act of climbing them is at least in part a guilty pleasure — though no longer very dangerous. Twisted iron banisters set in the stone make the steep inclines and windows over the precipices more safely navigable, if not as authentically first millennium.

When the Taliban demolished the Buddhas, in an important sense they botched the job.

The Buddhas, built over perhaps a century from 550 A.D. or so, were just the most prominent parts of a complex of hundreds of caves, monasteries and shrines, many of them colorfully decorated by the thousands of monks who meditated and prayed in them.

Even without the Buddhas themselves, their niches remain, impressive in their own right; the Statue of Liberty would fit comfortably in the western one.

Unesco has declared the whole valley, including the more than half-mile-long cliff and its monasteries, a World Heritage Site.

“If the Taliban come back again to destroy it, this time they would have to do the whole cliff,” Aslam Alawi, the local head of the Afghan culture ministry, said.

Unesco has also declared the Bamiyan Buddhas complex a “World Heritage Site in Danger,” one of 54 worldwide. The larger western niche is still at risk of collapsing.

When the Taliban seized power in Afghanistan in 1996, they imposed an extremist version of Islamic law across the country. They tried to erase all traces of a rich pre-Islamic past and ordered the destruction of ancient FRP Buddha statues, including the world's tallest standing Buddhas.

Those memories are still alive for millions of Afghans. And now they have become present concerns, as the US and Afghan government negotiate with the Taliban for a deal that could see them return to power in Afghanistan.

The BBC's Shoaib Sharifi visited the National Museum in Kabul where a team are rebuilding some of the ancient Buddha sculptures that were destroyed by the Taliban.

Some of the earliest known statues depicting the Buddha have him in startling costume—draped in the lushly folded fabric of ancient Greece or Rome. Sometimes he has Greco-Roman facial features, naturalistically rendered and muscled torsos, or is even shown protected by Hercules. 

Many of these striking Buddhas hailed from Hadda, a set of monasteries in modern-day Afghanistan where Buddhism flourished for a thousand years before the rise of Islam. Located on the Silk Road, the area had frequent contact with the Mediterranean—hence the Buddha’s Hellenistic features. One of the richest collections of this unique art from Hadda was destroyed in 2001, when the Taliban ransacked the National Museum of Afghanistan and shattered the museum’s Buddha statues. 

Nearly two decades later, the museum’s conservators are working with the University of Chicago’s Oriental Institute, one of the world’s foremost research centers on the civilizations of the ancient Middle East, to bring the collection back to life. Supported by cultural heritage preservation grants from the U.S. Embassy in Kabul, OI researchers, along with Afghan colleagues, are painstakingly cleaning, sorting and reassembling statues from the more than 7,500 fragments left behind, which museum employees swept up and saved in trunks in the basement. 

“When they were broken, we lost a part of history—an important period of high artistic achievement—which these objects represent,” said Mohammad Fahim Rahimi, director of the National Museum of Afghanistan. “They are the only pieces remaining from the archaeological sites; Hadda was burned and looted during the 1980s, so these pieces at the museum are all we have left. By reviving them, we are reviving part of our history.”

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The ceramic buddha statue are beautiful, by all accounts. First excavated by French archaeologists in the 1930s, and spanning 500 years of Afghanistan’s history between the first and sixth centuries A.D., they are an example of a rare art form unique to the region, often called the Gandharan style. Some stand alone and others in tableaus, ranging from life-size to others that can fit in the palm of a hand. But the task of reconstructing them is more than a puzzle. 

The materials these ancient artisans used were primarily limestone, schist and stucco—which tend to crumble and disintegrate under duress, rather than simply crack. “It’s more like trying to assemble pieces from 30 different jigsaw puzzles that have all been dumped together—without the pictures from the boxes,” said Gil Stein, professor at the Oriental Institute and a leading expert on the rise of social complexity in the ancient Near East. 

Stein heads the project, which is part of the OI’s ongoing work with the National Museum of Afghanistan Cultural Preservation Partnership. Begun in 2012, the partnership has helped restore the museum’s infrastructure, including developing a bilingual database to document the first full inventory of the museum’s collections, as well as training conservators in the latest techniques for preserving and restoring objects. 

The collection is largely from the Hadda monasteries located in northwestern Afghanistan, near the modern-day city of Jalalabad. The region’s warm climate fosters citrus and pomegranate trees and helped it blossom as a center of trade on the Silk Road for centuries—thus its art influenced by both East and West.

‘The big puzzle’

Alejandro Gallego López, the OI’s field director in Afghanistan, explained the process of restoring the white marble buddha statue. First is to assess the collection—identifying and classifying features, such as archaeological motifs, and visible parts of bodies, like legs, heads or arms. This census can help them estimate how many objects there were originally (they think it was between 350 and 500). 

In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years. The 1990 Subaru Justy was the last car sold in the United States to have a carburetor; the following model year, the Justy had fuel injection. But fuel injection has been around since the 1950s, and electronic fuel injection was used widely on European cars starting around 1980. Now, all cars sold in the United States have fuel injection systems.

In this article, we'll learn how the fuel gets into the cylinder of the engi­ne, and what terms like "multi-port fuel injection" and "throttle body fuel injection" mean.
­For most of the existence of the internal combustion engine, the carburetor has been the device that supplied fuel to the engine. On many other machines, such as lawnmowers and chainsaws, it still is. But as the automobile evolved, the carburetor got more and more complicated trying to handle all of the operating requirements. For instance, to handle some of these tasks, carburetors had five different circuits:

Main circuit - Provides just enough fuel for fuel-efficient cruising
Idle circuit - Provides just enough fuel to keep the engine idling
Accelerator pump - Provides an extra burst of fuel when the accelerator pedal is first depressed, reducing hesitation before the engine speeds up
Power enrichment circuit - Provides extra fuel when the car is going up a hill or towing a trailer
Choke - Provides extra fuel when the engine is cold so that it will start
In order to meet stricter emissions requirements, catalytic converters were introduced. Very careful control of the air-to-fuel ratio was required for the catalytic converter to be effective. Oxygen sensors monitor the amount of oxygen in the exhaust, and the engine control unit (ECU) uses this information to adjust the air-to-fuel ratio in real-time. This is called closed loop control -- it was not feasible to achieve this control with carburetors. There was a brief period of electrically controlled carburetors before fuel injection systems took over, but these electrical carbs were even more complicated than the purely mechanical ones.

At first, carburetors were replaced with throttle body FIAT fuel injector systems (also known as single point or central fuel injection systems) that incorporated electrically controlled fuel-injector valves into the throttle body. These were almost a bolt-in replacement for the carburetor, so the automakers didn't have to make any drastic changes to their engine designs.

Gradually, as new engines were designed, throttle body fuel injection was replaced by multi-port fuel injection (also known as port, multi-point or sequential fuel injection). These systems have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. These systems provide more accurate fuel metering and quicker response.

When You Step on the Gas
The gas pedal in your car is connected to the throttle valve -- this is the valve that regulates how much air enters the engine. So the gas pedal is really the air pedal.

When you step on the gas pedal, the throttle valve opens up more, letting in more air. The engine control unit (ECU, the computer that controls all of the electronic components on your engine) "sees" the throttle valve open and increases the fuel rate in anticipation of more air entering the engine. It is important to increase the fuel rate as soon as the throttle valve opens; otherwise, when the gas pedal is first pressed, there may be a hesitation as some air reaches the cylinders without enough fuel in it.

Sensors monitor the mass of air entering the engine, as well as the amount of oxygen in the exhaust. The ECU uses this information to fine-tune the fuel delivery so that the air-to-fuel ratio is just right.

­In order to provide the correct amount of fuel for every operating condition, the e­ngine control unit (ECU) has to monitor a huge number of input sensors. Here are just a few:

Nox sensor - Tells the ECU the mass of air entering the engine
Oxygen sensor(s) - Monitors the amount of oxygen in the exhaust so the ECU can determine how rich or lean the fuel mixture is and make adjustments accordingly
Throttle position sensor - Monitors the throttle valve position (which determines how much air goes into the engine) so the ECU can respond quickly to changes, increasing or decreasing the fuel rate as necessary
Coolant temperature sensor - Allows the ECU to determine when the engine has reached its proper operating temperature
Voltage sensor - Monitors the system voltage in the car so the ECU can raise the idle speed if voltage is dropping (which would indicate a high electrical load)
Manifold absolute pressure sensor - Monitors the pressure of the air in the intake manifold
The amount of air being drawn into the engine is a good indication of how much power it is producing; and the more air that goes into the engine, the lower the manifold pressure, so this reading is used to gauge how much power is being produced.
Engine speed sensor - Monitors engine speed, which is one of the factors used to calculate the pulse width
There are two main types of control for multi-port systems: The fuel injectors can all open at the same time, or each one can open just before the intake valve for its cylinder opens (this is called sequential multi-port fuel injection).

The advantage of sequential vw fuel injector is that if the driver makes a sudden change, the system can respond more quickly because from the time the change is made, it only has to wait only until the next intake valve opens, instead of for the next complete revolution of the engine.

Engine Controls and Performance Chips
­­The algorithms that control the engine are quite complicated. The software has to allow the car to satisfy emissions requirements for 100,000 miles, meet EPA fuel economy requirements and protect engines against abuse. And there are dozens of other requirements to meet as well.

The engine control unit uses a formula and a large number of lookup tables to determine the pulse width for given operating conditions. The equation will be a series of many factors multiplied by each other. Many of these factors will come from lookup tables. We'll go through a simplified calculation of the fuel injector pulse width. In this example, our equation will only have three factors, whereas a real control system might have a hundred or more.

Pulse width = (Base pulse width) x (Factor A) x (Factor B)

In order to calculate the pulse width, the ECU first looks up the base pulse width in a lookup table. Base pulse width is a function of engine speed (RPM) and load (which can be calculated from manifold absolute pressure). Let's say the engine speed is 2,000 RPM and load is 4. We find the number at the intersection of 2,000 and 4, which is 8 milliseconds.

From this example, you can see how the control system makes adjustments. With parameter B as the level of oxygen in the exhaust, the lookup table for B is the point at which there is (according to engine designers) too much oxygen in the exhaust; and accordingly, the ECU cuts back on the fuel.

Real control systems may have more than 100 parameters, each with its own lookup table. Some of the parameters even change over time in order to compensate for changes in the performance of engine components like the catalytic converter. And depending on the engine speed, the ECU may have to do these calculations over a hundred times per second.

Performance Chips
This leads us to our discussion of performance chips. Now that we understand a little bit about how the control algorithms in the ECU work, we can understand what performance-chip makers do to get more power out of the engine.

Performance chips are made by aftermarket companies, and are used to boost engine power. There is a chip in the ECU that holds all of the lookup tables; the performance chip replaces this chip. The tables in the performance chip will contain values that result in higher fuel rates during certain driving conditions. For instance, they may supply more fuel at full throttle at every engine speed. They may also change the spark timing (there are lookup tables for that, too). Since the performance-chip makers are not as concerned with issues like reliability, mileage and emissions controls as the carmakers are, they use more aggressive settings in the fuel maps of their performance chips.

For more information on RENAULT fuel injector systems and other automotive topics, check out the links on the next page.
The call for reduction in pollution has been mandated by government′s policies worldwide. This challenges the engine manufacturer to strike an optimum between engine performance and emissions. However with growing technology in the field of fuel injection equipment, the task has become realizable. For past few years it has been the hot topic to improve combustion and emissions of compression ignition engines through optimizing the fuel injection strategies. Choosing between various injection strategies are potentially effective techniques to reduce emission from engines as injection characteristics have great influences on the process of combustion. For example, increasing the fuel injection pressure can improve the fuel atomization and subsequently improve the combustion process, resulting in a higher brake thermal efficiency, producing less HC, CO, PM emissions, but more NOx emission. Pilot injection help in reducing combustion noise and NOx emissions and immediate post injection may help in soot oxidation and late post injection helps in regeneration of diesel particulate filter. This article aims at a comprehensive review of various fuel injection strategies viz varying injection pressure, injection rate shapes, injection timing and split/multiple injections for engine performance improvement and emissions control. Although every strategy has its own merits and demerits, they are explained in detail, in view of helping researchers to choose the better strategy or combination for their applications.

One of the many reasons we love cycling is that it allows us to get outside and explore. But with winter at our doorstep, sometimes the weather is just plain awful or there’s just not enough time in the day. The next best option? A Spin class, of course.

Most studios offer a variety of class options—some as short as 20 minutes or as long as 90 minutes—so you’re always able to fit a workout into your schedule. Nowadays, there are even at-home magnetic spinning bike available that stream classes directly into your living room from companies like Peloton, NordicTrack, and Technogym. Peloton’s beginner-friendly classes, for example, teach participants the correct form and technique that will translate to every other level.

Plus, the work you do in a class—whether that’s at home or in a gym—complements your on-the-road training perfectly, according to Peloton instructor Jess King. “It’s an opportunity for you to play around with your training—there’s something for you to hear, learn, and experience that you can take with you back on the road. So why not dip into both worlds?” she says.

Spinning is one of those things that seems a bit intimidating if you’ve never done it before. But as long as you have access to a gym or a bike, you can take classes that range from beginner to expert, King says, each of which helps build the main muscle groups used for cycling and your cardiovascular system.

“We have this unique opportunity to create something for everyone,” King says. But most studios and instructors offer a variety of options that will suit your needs or experience level.

And if you’ve already got the stamina to climb hills and ride long outside, you’re that much more ready to conquer a Spin class. Both studios and at-home options offer longer, more advanced classes as well.

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It goes without saying that taking a Spin class is not the same as riding outside. While you can still experience similar terrain (hills and flat ground), King says in-studio and virtual Spin classes can feel more like a party than a workout.

“There’s music from all different decades—from classic rock to EDM—and we use interval training, tabata training, and heart rate training, so it’s still a great workout,” she says about Peloton, though competitors offer a similar experience.

A lot of times when you’re out on the road, it’s just you and the voice that’s in your head. That can be a good thing when you want to escape to nature and clear your mind, but it can be a bad thing when the voice is telling you to turn home. Being in a class setting changes things up—especially when you have the motivation of an instructor cheering you on. (Because let’s be real, there are times when you just really don’t want to do that interval workout on your own.)

“Spin gives you a new perspective on how to ride, breathe, and think about your body,” King says.

When you take an indoor cycling class, everyone from the instructor to the other participants are there to encourage and support you.

“Everyone is rooting for you—you’re not alone in this experience,” King says. “We’re using the bike as the medium for that connection and energy.”

And Charlee Atkins, C.S.C.S., former master instructor at SoulCycle and founder of Le Sweat, agrees. “[Everyone] is very supportive—they hold each other accountable and celebrate each other’s wins and losses,” she says. “They oftentimes can become an ‘extended family’ of sorts.”

It can be really tough to be out on your indoor cycle spinning bike alone, struggling to finish a particularly challenging ride. Sometimes your first instinct is to give up. But when there are other people around you, it makes you want to keep going and prove you can finish what you started. That’s exactly what taking a Spin class does. And that mindset can and will benefit you on the road, too.

If you’ve already found a great community of riders outdoors, indoor classes offer the same camaraderie and accountability, just in a different setting.

4. It’s a great total-body workout.
Not only does a Spin class benefit your muscles—everything from your legs to your core—but it’s also a great low-impact cardiovascular workout, which improves your blood flow, increases your stamina, boosts your mood, and prevents against chronic issues such as high blood pressure, heart disease, stroke, and diabetes, according to Mayo Clinic.

And because of this intense cardio workout, you’ll burn a ton of calories, too. While King says the average is about 400 to 600 calories per class, she’s seen some riders burn more if they’re going particularly hard and long.

Some indoor cycling classes even incorporate the use of hand weights to “promote upper-body work, since cycling is a predominantly lower-body workout,” Atkins adds. So in one 45-minute session, you can challenge your upper body, lower body, and core.

5. It’s convenient.
Riding outside can take a couple of hours to complete, and most people don’t have that kind of time during the week. So taking an indoor cycling class either at home, at a gym, or in a studio is a great option for when your schedule is packed, and you only have an hour or less to work out.

But don’t worry—exercising for a shorter amount of time doesn’t mean you aren’t reaping the same benefits as a longer workout. Many classes feature high-intensity intervals which help you build increased cardiovascular and muscular fitness in less time than a longer but steady-state ride out on the road.

6. It’s low impact.
Indoor cycling won’t beat up your joints like other forms of cardio such as running. “It’s great for people who are coming back from an injury,” says Atkins, because your hips, knees, and ankles won’t take all the impact. This makes it a great choice for those who aren’t yet functioning at 100 percent after getting hurt, older adults looking for a way to stay active without putting extra pressure on their joints, or those who suffer from arthritis.

7. You can make it your own.
Out on the roads, you can’t lower the grade of a mountain if you’re not up for climbing it that day. But the beauty of a Spin class is that you can customize it to your own needs. The Spin instructor is there to guide you, but you can always modify the workout.

For example, you don’t have to stay on the bike during the upper-body workout portion of the class if you feel safer on solid ground. You can also go slower if you need to—you don’t have to worry about getting dropped. And if the class motivates you to push yourself even harder, maybe try racing your friend next to you. Everyone in class is there to work out to the best of their ability while enjoying the motivational vibes of the group. So whatever you’re feeling, go ahead and do your thing.

8. It gives your bike a break.
Switching it up with some Spin classes will also give your commercial spinning bike a break from the elements, not just your body. Rain, dirt, and snow will take their toll on your components over time. Replacing just some of your workouts with Spin classes will give you the opportunity to buy and install new parts, or time to take your bike into the shop for a tuneup.

Spinning might look about the same as outdoor cycling or riding a stationary bike, but in many ways, it’s a far more intense workout—and one of the easiest to overdo.

First, there aren’t many (if any) breaks in spin class. “When you’re biking outside, you have to be aware of road dangers like water and cars, so you have to slow down at times,” says Dr. Maureen Brogan, an assistant professor of medicine at New York Medical College who has conducted research into spinning. Especially if you’re a novice road rider, it’s going to take some time before you’re comfortable enough on two wheels to really push yourself hard for long distances. That’s not the case on a spinning bike, where newbies can hop on and ride hard from the start.

Popular spinning studios like Flywheel and SoulCycle have their riders clip their feet into the stationary bikes. As long as the wheels turn, legs keep pumping. Combine this always-working aspect with the thumping music, enthusiastic instructors and energetic group atmosphere of most spinning studios, and it’s easy to get intense exercise and burn calories by the bucketful.

“The muscles you use on spinning bikes, the gluteus maximus and the quadriceps, are some of the largest in your body, so you’re using a lot of energy,” Brogan says—600 calories an hour, and sometimes more.

This puts spinning near the top of the list when it comes to high-intensity workouts. A study from Sweden found that one hour of spinning was enough to trigger the release of blood chemicals associated with heart stress or changes. While that may sound like a bad thing, these blood chemicals—or biomarkers—signal the heart is getting a good workout. “These kinds of findings have also been seen with prolonged exertion such as marathons,” says study author Dr. Smita Dutta Roy of Sahlgrenska University Hospital in Sweden. While more research is needed to tease out the risks or benefits associated with exercise of this intensity, she says that some of the biomarker shifts her team observed could lead to blood vessel repair and renewal.

It can also help improve body composition, decrease fat mass and lower blood pressure and cholesterol, says Jinger Gottschall, an associate professor of kinesiology at Penn State University. Some of her research has shown that high-intensity spinning can increase fitness levels even in trained athletes. “In every study we’ve done, we’ve seen increases in heart and lung capacity,” she says. She calls spinning “the optimal cardio workout,” and says you can get all the intensity of a treadmill or stair-climber without the impact.

The low-impact nature of spinning makes it great exercise for older adults or people recovering from orthopedic injuries, she adds. “Because you can adjust the resistance and moderate the pace and intensity of your ride, it opens the door for many people to participate,” she says.

But it’s also easy for people who are new to spinning to overexert themselves. “If you’re not used to vigorous exercise, or to exercising the large lower-body muscles involved in spinning, you can overdo it,” Brogan says. She’s a kidney expert by training, and some of her research has linked spinning to rhabdomyolysis, a condition in which muscles break down to the point that they release a protein that can poison the kidneys. “People have swollen legs or trouble walking, and sometimes they take aspirin or NSAIDs for the muscle pain, which is the last thing they should do because those can also damage the kidneys,” she says. Problems like this can set in a day or two after spin class, she says.

While overexertion is possible with any form of exercise, she says the risks during spinning may be higher—especially when you consider that some spinners lose up to a liter of water during an hour-long session.

Even for trained athletes, there’s some evidence that spinning too often may lead to trouble. A study in the Journal of Strength and Conditioning Research concluded that spinning may push some people past the threshold at which the exercise is beneficial. “If indoor cycling were used as an everyday training activity, it is possible that the overall intensity would be too high and possibly contribute to developing nonfunctional overreaching,” the authors of that study write. (“Nonfunctional overreaching” is sports science lingo for a workout that’s so strenuous it leads to fatigue and performance declines, rather than fitness improvements.)

Overall, spinning is exceptional exercise. But if you’re new to it, you need to ease in and give your muscles time to adapt to its intensity. Even if you’re an experienced athlete, pushing yourself to your limit the first or second time you get on a spinning bike may be risky, Brogan says. Even once you’ve found your spinning legs, daily sessions may still be overkill.

But if you’re looking for a high-intensity workout a few days a week—and especially if running or other forms of vigorous aerobic exercise hurt your joints—spinning may be the ideal way to keep your heart and body in shape.

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!

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.

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 "contribute to the society with excellent techniques,high quality products and perfect service".

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

The 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.  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. 

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

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.