Plowing


C. Role of Shearing and Plowing—Explanation of Amontons Law  [c.434]

The plowing contribution can be estimated by employing a rider that is very  [c.434]

Fig. XII-3. Illustration of (a) shearing and (b) plowing actions. Fig. XII-3. Illustration of (a) shearing and (b) plowing actions.
Com as com flakes, sweet com, com as various types of flour and meal, popcorn, other snacks foods such as chips, and com juice as sweeteners, com used in fermentation for beer and in the production of alcohol, and corncobs and stalks used as carriers for various chemicals and medications, as fiber sources, and for the improvement of soil condition by plowing under stalks, are some of the uses for this versatile crop. See Ref. 75 for more information on corn.  [c.360]

Crop Rotation. Prior to about 1945, considerable dependence was placed on crop rotation as a means of supplying nitrogen. Certain plant varieties, particularly legumes such as peas and clovers, through a symbiotic relationship with certain sod bacteria, have the abdity to utilize atmospheric nitrogen for nutrition. Sod bacteria infect the roots of these plants, causing the development of characteristic nodules. At the sites of these nodules, by mechanisms that are quite compHcated, elemental atmospheric nitrogen becomes fixed and is absorbed into the root system of the plant (see Nitrogen fixation). In the farming system known as crop rotation, advantage is taken of this biological fixation by growing first a nitrogen-fixing legume, plowing it into the ground, and foUowing with growth of a nonlegume farm crop. This is an effective system, said to have been recognized even by the early Greeks. However, for modem high yield agriculture, it is inefficient. Alternate growing seasons are, to a large extent, lost by growing the legumes. Also, modern hybrid varieties of grains are voracious consumers of nitrogen, having requirements beyond the supply capabdity of a plowed-under legume crop.  [c.216]

Pan Type. The mulling action of this mixer is similar to the action of a mortar and pesde. Scrapers move the materials from the center and side of a pan into the path of rotating wheels where mixing takes place. The pan may be of the fixed or rotating type. Discharge is through an opening in the pan. The dow type uses rotating plows in a rotating pan to locally mix and intermix by the rotation of plows and pan, respectively.  [c.440]

An inclined-disk agglomerator consists of a tilted rotating plate equipped with a rim to contain the agglomerating charge (Fig. 4). SoHds are fed continuously from above or from the front onto the central part of the disk, and product agglomerates discharge over the rim. Moisture or other binding agents can be sprayed on at various locations on the plate surface. Adjustable scrapers and plows maintain a uniform protective layer of product over the disk surface and also control the flow pattern of material on the disk. Plate angle can be adjusted from 40 to 70° to the horizontal to obtain the best results, and both constant-speed and variable-speed motors are available as disk drives. Dust covers can be fitted when requited. Characteristics of some of the range of inclined disks offered by one manufacturer are given in Table 3.  [c.113]

Sorption and transport processes are directiy or indirectiy affected by soil properties such as soil moisture, temperature, pH, and organic carbon content. Tillage systems affect these same soil properties (73,74). Conventional tillage systems can decrease moisture compared to conservation tillage systems, resulting in decreased degradation, volatilization, and leaching of the pesticide. Different tillage systems have different effects on soil temperature. In general, increased tillage increases soil temperature in the spring and summer. Rates of chemical and microbiological reactions and volatilization are temperature-dependent. Continuous appHcation of ammonium fertilizer in conservation tillage systems decreases pH substantially. Tillage dramatically affects organic carbon content of sod. Once a sod is plowed for the first time, the organic carbon content begins to decrease. Leaving a residue on the surface, as in conservation tillage, increases the organic carbon content of the sod. Sod microbial populations can be substantially greater in conservation tillage systems.  [c.223]

R. S. H. Mah, Chemical Process Structures and Information Plows, Butterworth Co. (Pubhshers) Ltd., London, 1990.  [c.85]

Plate Dryers The plate dryer is an indirect Treated, fully continuous dryer available for three modes of operation atmospheric, gastight, or fall vacuum. The dryer is of vertical design, with horizontal, heated plates mounted inside the housing. The plates are heated by either hot water, steam, or thermal oil, with operating temperatures up to 320°C possible. The product enters at the top and is conveyed through the dryer by a product-transport system consisting of a central-rotating shaft with arms and plows. (See dryer schematic. Fig. 12-78.) The thin product layer (approx. V2 in depth) on the surface of me plates, coupled with frequent product turnover by the conveying system, resalts in  [c.1216]

The heavy, wide roller rides over the material. There is some skidding action where the rollers engage the mass of materials. This gives local shearing plus coarse-scale mixing which is aided by the plows and scrapers.  [c.1766]

The Raymond ring-roller mill (Fig. 20-50) is of the internal air-classification type. The base of the mill carries the grinding ring, rigidly fixed in the base and lying in the horizontal plane. Underneath the grinding ring are tangential air ports through which the air enters the grinding chamber. A vertical shaft driven from below carries the roller journals. Centrifugal force urges the pivoted rollers against the ring. The raw material from the feeder drops between the roUs and ring and is crushed. Both centrifugal air motion and plows move the coarse feed to the nips. The air entrains fines and conveys them up from the grinding zone, providing some classification at this point. An air classifier is also mounted above the grinding zone to return oversize.  [c.1862]

Once final belt selec tion has been made, idlers and return rolls can also be selected. Figure 21-3 indicates the wide variety of belt supports for bulk-handling apphcations. Figure 21-3 7 and b consists of flat-belt arrangements of rollers or plate which allow material to be discharged by simple V-shaped plows. The flat plate-supported belt allows sidewalls to be erected to prevent dribble or to build up larger loads on the flat belt. As in Fig. 21-, larger capacity can also oe achieved by troughing the plate. The 20° troughing idler with equal-length rolls (Fig. 21-3c) is the most common, with lighter materials adaptable to 45° idlers with short or long side rolls (Fig. 21-3cZ and e).  [c.1917]

Area should he fenced, graded for runoff control, and disked or plowed before waste application.  [c.2260]

Foreign bodies embedded in cake cause heat/sparks during removal (plowing out).  [c.67]

Loose or mis- Preventative maintenance and operator prestart placed internal checklist hardware causes heat/sparks during plowing out. CCPS G-22  [c.68]

Vibration during Check plow and linkage for loose compo-plowing out—can nents/wear lead to premature. sharpen plow or use serrated blade for hardened equipment failure heels and a potential ignition source— Manually remove heel more frequently see above. Plow at lower bowl speed Advance plow more slowly Make sure plow system is well damped Avoid air actuated plows Avoid use of full depth plows with hard cakes Use nitrogen knife to scrape centrifuge  [c.68]

The degree of utilization of the above inputs varies widely, but generally increases with economic development. These modern technologies reduce the time and labor needed for land preparation, plowing, planting, and harvesting crops. In favorable areas, it also aids double cropping management.  [c.18]

One reason for the extensive use of herbicides in the 1990s was the significant change in farming practices. No-tUl or conservation tillage is being used on larger and larger acreages of U.S. croplands. Instead of plowing and harrowing fields prior to planting, seeds are drilled direcdy into the soil containing plant residues from the previous crop. Prior to drilling the seed, all weedy vegetation is killed using a contact herbicide such as paraquat, and full-season weed control is achieved with a soil-appHed herbicide such as atra2ine. No-tUl generally requires more herbicide usage than conventional tillage, but reduces soil erosion, permits greater water infiltration, and is more economical from a labor standpoint.  [c.213]

There are three basic strategies to control the amount of pesticide in mnoff reduce the amount of mnoff of soil and water lower the amount of pesticide in the mnoff and retard the field-to-stream deHvery of pesticide (49). Cultural practices can reduce the pesticide in mnoff. For instance, pesticide incorporation and contour plowing can lead to significant reductions in dissolved and sorbed pesticide concentrations, and in total metolachlor loss in mnoff, relative to appHcation as a pre-emergence spray with cross-contour plowing (50). Pesticide mnoff is also affected by timing of appHcation. For example, twice as much atra2ine-appHed pre-emergent was in the mnoff water and sediment compared to that of appHed post-emergent (51).  [c.222]

The badeycom, inch, foot, yard, rod, furlong, mile, league, ell, fathom, and chain are units of length that the North American colonies inherited from the British. The inch was originally the length of three barleycorns the yard was the distance from the tip of the nose to the tip of the middle finger on the outstretched arm of a British king (Henry 1) the acre was the amount of land plowed by a yoke of oxen in a day. This system of units is very old and may be traced back to ancient Egypt.  [c.307]

Multiple-Hea.rth Roasters. The circular types consist of a series of hearths arranged vertically in such a way that the ore entering the top is rabbled and dropped down from hearth to hearth, until it is completely oxidized. The hearths are usually stationary and the plows revolve, such as in the Wedge, Herreshoff, Ord, Skinner, and other roasters (21). In other furnaces, the hearths revolve and the rabbles are fixed, eg, the deSpirlet and its modification, the Barrier.  [c.399]

A conventional circular-wedge roaster consists of a brick-lined steel shell with hearths arched gendy upward from the periphery to a central shaft. The brick hearths may number from 8 to 16 and are ca 1 m apart. The central steel shaft (ca 1.2 m in diameter) revolves at 1 rpm or less carrying two rabble arms per hearth. These rabbles, cooled with air or water, plow the ore from the outside to the center of the hearth where it is dropped to the next hearth for plowing in the opposite direction. The calcine thus proceeds to the bottom where it is dropped into a conveyor. The sulfide sulfur at this point is ca 3.5% (22).  [c.399]

Runway Deicing. Deicing compounds are appHed to the mnway under certain conditions to assist in the removal of frozen accumulations of snow and ice that cannot be readily removed by mechanical means such as plowing. The primary purpose of chemical deicing is not to melt the surface ice and snow, but rather to diffuse through the snow and ice to break the bond between the ice and the mnway. Once the ice—surface bond is broken, the remaining frozen accumulation can then be removed by mechanical means. The use of chemical deicing often reduces the amount of time and equipment used in snow removal. Runway antiicing can also be achieved by applying certain deicing compounds in anticipation of freezing rain, snow, or icing conditions. It is critical that both deicing and antiicing be conducted in a closely controUed manner where the appHcation rate is monitored and the mnway is monitored for sHpperiness. Improperly appHed mnway deicing fluids may create a sHppery condition.  [c.190]

Shell and internal device rotate. The countercurrent miiller (Fig. I9-9g), which is in this categoiy, is mentioned under MuUer mixer. This machine has a clockwise rotating mixing pan with a counterclockwise rotating mixing tool head mounted off center of the pan, thus providing a planetary mixing pattern. For the mixing of n ee-flowing solids not requiring the snearing and compressive action of mullers, plows are sometimes used alone. When used with mullers, plows deflect material into their path. Special mixing tools are also available.  [c.1766]

Design and Operation The pan crusher (Fig. 20-30) consists of one or more grinding wheels or mullers revolving in a pan the pan may remain stationaty and the mullers be driven, or the pan may be driven while the iTuillers revolve by friction. The mullers are made of tough alloys such as Ni-Hard. Iron scrapers or plows at a proper angle feed the material under the mullers.  [c.1848]

Wastes spread on the surface should he disked or plowed into the soil soon after apphcation (1 to 7 days). To promote aerobic conditions and rapid hioconversion of the wastes the soil-waste mixture should he cultivated periodically.  [c.2260]

The modem process for black powder begins with charcoal and sulfur in a hollow drum with / steel balls. This ball mill pulverizes the contents as the dmm rotates through the tumblini the steel balls. The potassium nitrate is crushed separately using heavy steel rollers. A mixture >ji several hundred pounds of potassium nitrate, charcoal, and sulfur goes onto a cooking pan — --e it is continuously turned over by plows. Next, it is ground and mixed by two rotating iron whet ich weighing about 10 tons. The process takes several hours with water being added to keep the ure moist. The product is put through wooden rolls to break up the larger lumps and formed into cakes under about 4,000 psi pressure. Coarse-toothed rolls crack the cakes into manageable pieces and the mixture is rolled to the desired size. Glazing (a graphite coating to make it flow better) tumbles the grains for several hours in large wooden cylinders to round the comers while forced air cir tion adj moisture content. After glazing it is graded by the size of the grains. Bl. .. cris  [c.273]

Sturz, m. plunge, drop, fall, overthrow rush, dash failure (in business) waterfall (/ron) slab, plate, -acker, m. new-plowed land, -bomben, n. dive bombing, -blech, n. thin plate iron, (black) sheet iron.  [c.435]

The well-documented case of the United States serves as an illustration. During the period 1870 to 1900 the farm population was increased through a rapid expansion of the agricultural area. The agricultural labor force increased by 60 percent, but there was a replacement of labor by nonland capital in the form of horses and mules. New and more efficient types of horse-drawn machinery including plows, cultivars, seed drills, grain harvesters, and mowers became available.  [c.18]

After Thomson nothing particular transpired, until a number of people, of whom Joseph Larmor in 1895 was perhaps first, entertained what historians now call the clcctromaglietic worldview. Instead of basing electromagnetism on dynamics, as many had tried, could one base dynamics on electromagnetism How far this thought would have gone is unclear had it not been for another even greater leap of Thomson s, this time experimental his discovery of the electron. In 1897, by combining measurements of two kinds, he proved that cathode rays must consist of rapidly moving charged objects with a mass roughly one olie-thousandtli of the hydrogen atom s. Here was revolution—the first subatomic particle. Hardly less revolutionary was his conjecture that its mass was all electromagnetic. A shadow ship plowing through all electromagnetic sea That was Thomson s vision of the electron.  [c.1036]

Figures 10-4A, 10-4B, 10-4C, and 10-4D illustrate the usual construction of tinned-tube heat exchangers with the tins running parallel to the length of the tube. These are usually, but not always, installed with a tube or pipe outer shell. Typical tins are shown in Figure 10-152. Tube may be fabricated with tins attached by resistance welding rather than imbedding in the tube as shown in Figure 10-152B. The l.D. of the internal tinned pipe usually ranges from -1 V2 in., and the outside surrounding pipe shell can be 2 V2 in., 3 in., and 3 V2 in. nominal standard pipe size. The number of tins range from 18 for the -in. pipe, 24 or 32 for the 1 V2 -in. pipe, and 16 or 32 for the 1 V2 -in. pipe with V2 -in. tin height, per manufacturer Griscom-Russell/Ecolaire Corp. The tins of Figure 10-152B are imbedded longitudinally in groves plowed into the tube s outer surface. The displaced metal is squeezed back against the imbedded tin base to form a tight metal-metal bond. This bond is not affected by changes in temperature. Figures 10-4A, 10-4B, 10-4C, and 10-4D illustrate the usual construction of tinned-tube heat exchangers with the tins running parallel to the length of the tube. These are usually, but not always, installed with a tube or pipe outer shell. Typical tins are shown in Figure 10-152. Tube may be fabricated with tins attached by resistance welding rather than imbedding in the tube as shown in Figure 10-152B. The l.D. of the internal tinned pipe usually ranges from -1 V2 in., and the outside surrounding pipe shell can be 2 V2 in., 3 in., and 3 V2 in. nominal standard pipe size. The number of tins range from 18 for the -in. pipe, 24 or 32 for the 1 V2 -in. pipe, and 16 or 32 for the 1 V2 -in. pipe with V2 -in. tin height, per manufacturer Griscom-Russell/Ecolaire Corp. The tins of Figure 10-152B are imbedded longitudinally in groves plowed into the tube s outer surface. The displaced metal is squeezed back against the imbedded tin base to form a tight metal-metal bond. This bond is not affected by changes in temperature.

See pages that mention the term Plowing : [c.434]    [c.434]    [c.435]    [c.436]    [c.59]    [c.136]    [c.1221]    [c.1647]    [c.1647]    [c.1940]    [c.440]    [c.770]   
Physical chemistry of surfaces (0) -- [ c.434 ]