Agricultural machinery and technologies (E-Journal) / Сельскохозяйственные машины и технологии
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Расчет параметров подсушки растительного сырья
Get PDFThe authors described properties of the vegetable waste (VW) as object of burning in fire chambers of grain dryers. Though VW are often characterized by low combustion heat (10-12 MJ per kg), they could be considered as the valuable low-ash biological fuel which almost not contain ssulphur compounds and not pollute environment at the correct organization of burning process. Burning in a low-temperature circulating and vortex layer allows to keep small particles (0.5-3.0 mm) in a reaction zone before full burning out. Low-temperature condition of burning (600-700 degrees Celsius) excludes slagging of surfaces of a fire chamber, including heatexchange ones, and also reduces poison emission in the atmosphere. Precede subdrying of the VW particles and burning period have often the same duration. Duration of subdrying is calculated on the basis of the heatmass transfer equations. Transfer of heat when subdrying of small particles (less than 0.5-1.0 mm) is carried out by heat conductivity, when large particles (more than 1.0 mm) subdrying this process is convective. Adequacy of calculation formulas was estimated by the available experimental results of VW particles burning. Satisfactory coincidence (12 percent measure of inaccuracy) is received. The same coincidence is characteristic for calculated dependence at the equivalent coefficient of heat conductivity which value exceeds a table one by 25 percent. If a fuel is low-reactionary and solid, with a caloric content of 15 MJ per kg so burning of it in the furnace block aggregated with a grain drayer will be better at addition of high-reactionary liquid or gaseous fuel
Анализ тягового сопротивления элементов цилиндроидального плужного корпуса
Get PDFOne of the directions of decrease in power consumption of soil cultivation is change of a form and parameters of elements of a plow body like a plough share and a moldboard. Known mathematical expressions for determination of traction resistance of plows do not allow to consider various degree of loading of different parts of moldboard. The offered technique of definition of a horizontal component of traction resistance of a moldboard considers this difference in loading of a plow body surface. The component of surface resistance was determined due to summation of resistances of elementary horizontal components of a moldboard, with use of crumbling curves of a longitudinally vertical projection of the plow body. These curves are formed owing to horizontal transfer of points of intersection of secants of tcutting planes parallel to a furrow wall. If the deformator is completely digged in the soil, but there is no its turn and movement, then an expression for determination of work intensity of the active working element at penetration to the soil allows to calculate traction effort of an elementary horizontal component of moldboard resistance. The received expression can be used at approximation of curves of a longitudinally vertical projection of the plow body where the breast and median part of a moldboard are most loaded. Degree of loading of an elementary horizontal component of a moldboard is formed by the normal tension value which is comparable to deformation coefficient. The resistance component for soil layer ejecting considers the plowing depth, furrow width, speed of the plowing unit, density of the deformable soil, average value of a tilt angle of generators of a moldboard surface to a furrow wall. If moisture content in loamy soil is about 21 percent, plowing depth equals 0.20 m then the traction resistance of a 0.35 m wide moldboard will amount 1035 N
ТЕХНИЧЕСКАЯ ЭФФЕКТИВНОСТЬ ИСПОЛЬЗОВАНИЯ СЕЛЬСКОХОЗЯЙСТВЕННЫХ РЕСУРСОВ В РОССИИ
Get PDFTechnical efficiency of agricultural resources use in Russia is assessed. As methodology for calculations the author used Data envelopment analysis (DEA) which is the nonparametric method based on linear programming. The essence of the DEA method consists in an efficiency evaluation of homogeneous units of decision making proceeding from creation on the basis of real data (amounts of resources and amounts of types of output) of general border of production capabilities. CCR-I model was offerd as a specific kind of the DEA model. It is the radial DEA model with continual returns to scale and orientation to resources. The group of 54 countries included in a research consisted of the states of the CIS, BRIC, the EU, OECD. The time frames of calculation were established: 1992-2007 and 2008-2012 (owing to lack of uniform data for all time interval). Аmount of agricultural products was used as output. Agricultural lands, an economically active population in agriculture, farm machines and the equipment, a livestock, fertilizers were used in the form of resources. The main source of statistical data is FAOSTAT. From 54 countries under consideration Belgium, Greece, Israel, Malta and the Netherlands became leaders in technical efficiency of agricultural industry in 1992-2007. Inefficient use of agricultural resources, especially lands was established as a result of the conducted research in Russia. On average efficiency of use of agricultural lands in our country can be increased by 8 times, work - by 2-2.5 times, machines - by 2-3 times, a livestock and fertilizers - by 1.5-2 times. Good tendencies to growth of efficiency of agricultural production are notice in 2008-2012
Исследование давления колесного движителя на почву с учетом характеристики шины
Get PDFA maximum contact pressure is a key parameter characterizing a level of ecological impact of tractor propellers on the soil. The maximum pressure upon the soil varies with internal pressure in tires and vertical load of a wheel. An universal tire performance can be used at an assessment of change of contact pressure of a wheel propeller upon the soil. The authors offered a technique of definition and regulation of the maximum contact pressure of the wheel propeller upon the basic basis. This technique allows to set parameters for monitoring systems and regulation of the maximum pressure upon the soil by measurement of a tire deflection and change of pressure in tires. At statistical tests for determination of the maximum contact pressure it is necessary to consider the universal performance of the tire nomographically. This nomogram allows to consider visually influence of loading and internal pressure in the tire on a size of the maximum contact pressure. An internal pressure decrease in the tire makes it possible to reduce the maximum pressure upon the soil at constant loading. The authors investigated universal performances of the tires in the range of change of internal air pressure from 160 to 90 kPas. Change of internal pressure from 150 to 100 kPas reduce for the tire 15,5R38 the maximum contact pressure upon 13 kPas (9,6 percent): from 135 to 122 kPas. That corresponds to the admissible level of pressure upon the soil at its humidity in a layer of 0-30 cm: 0,5-0,6 minimum moisture-holding capacity during the spring period and 0,6-0,7 minimum moisture-holding capacity during the autumn period. In case of use of the tire 16,9R38 the maximum pressure upon the soil decreases from 84 to 75 kPas, that is by 10,4 percent
Оптимальное соотношение основных механизированных работ при прямоточном внесений удобрений
Get PDFUse of transport and technological means is carried out according to the direct-flow scheme and includes stage-by-stage performance as the main standard-setting operations (fertilizers transportation, movement and their distribution across a field), and auxiliary (return from a field and loading of fertilizers). The method of comparison of main types of operations at fertilizers application is given. An estimation criterion is a ratio of cargo movements on a road and across a field, proportionality coefficient between movement of freight and a fertilizers distribution area across the field. These indicators depend on transportation distances and doses of fertilizers application, and also on technology factor that is freight moving frequency across the field. The last characteristic is taken as the optimized parameter. An extremum of this indicator was searched due to a classical method. Optimum values of estimated indicators with the accounting of a variation of a ratio of load capacity and operating width of technical means are received. Concrete combinations of transportation distances and doses of fertilizers application are specified. The authors defined conditions of effective use of tractor and perspective automobile transport and technological means. They recommended to use the automeans allowing to change operating width. Realization of the stated methodological approach will make it possible to select an optimum ratio of the mechanized operations at direct-flow fertilizers application, to exclude additional cargo movements across the field, to cut fuel consumption, to increase productivity. Productivity of transport and technological means increases by 2.0; 1.3 and 1.15 times respectively to length of furrow 3; 9 and 27 km at fertilizers application by a dose of 0.06 kg per sq.m
ИССЛЕДОВАНИЕ ПЕРЕНОСА ВЛАГИ В ЗЕРНЕ ПРИ ОСЦИЛЛИРУЮЩЕЙ СУШКЕ
Get PDFAmong the innovative modes of seeds and grain drying the priority belongs to the oscillating one. But the modes with periodic lying allowing to increase significantly efficiency of seeds and grain drying including the increased moisture are least studied. Researches of moisture transfer are necessary for justification of the modes of safe and intensive drying. Realization of these modes allows to define heat-transfer coefficient and lying periods duration. It is caused by need of decrease in a gradient of surface moisture content and temperature of grain. Drying duration can be defined by equation which enter diffusion coefficient, the caryopsis radius, hull thickness (the dehydrated zone) and the size of moisture content of a kernel and a hull. After moisture evaporation intensity and safety of drying decrease therefore the lying is necessary for moisture redistribution. Under certain conditions width of an evaporation zone turns out to be much less characteristic size of the dried-up body so this zone can be replaced, for example, with grain hull thickness. On the basis of an admissible moisture removal and density of a thermal stream at intensive drying analytical expression was received. It can be used for calculation of the maximum heat-transfer coefficient and, respectively, of the drying agent speed which depends on its height, a specific surface of grain and a share of the warmth required for moisture evaporation. For conditions of drying of grain in the grain dryers the speed of the drying agent should not exceed 0.6 m per a second. The authors defined values of admissible size of heat-transfer coefficient (no more than 40 W per sq. m in terms of one degree) and lyings duration which is equal 10 min. The ratio of duration of the period of heating and cooling of grain is equal 10:10, optimum value of this ratio is 15:20
Влияние спектрального состава света на развитие сельскохозяйственных культур
Get PDFProductivity increase is one of priority problems of an agrarian complex in Russia. In many regions of the country cultivation of the majority of vegetables in an open ground is complicated or it is impossible because of severe climatic conditions. Plan cultivation in greenhouses, special aeroponic installations, phytothrones partially solves this problem. Production of various cultures suitable for food or as sowing material requires a complex of conditions, namely: optimum temperature, humidity and such the most important factor as illumination. Small intensity or shortage of light of a certain wavelength influence negatively on a morphogenesis of the grown-up cultures. Red and blue optical spectrums with lengths of waves of 640-660 nanometers and 430-460 nanometers respectively are most effective for growth of plants. Red highlighting promotes a phase of germination of wheat and increases by 2.5 times an indicator of a 1st leaf emergence. Influence of red and blue light on productivity of potato mini-tubers is experimentally defined: LED lamps in the mode of 660+450 nanometers can replace power-intensive sodium ones because values of weight of potato tubers at different lighting were close, having made 176.1 and 183.6 g respectively. At Brassica chinensis cultivation LED lamps can replace expensive sodium ones too: protein content made 17.4 mg per g at LED illumination and 16.4 mg per g in case of sodium lamps, and a share of soluble sugars from the total amount of sugars equals 100 and 50 percent respectively. At the illumination level of 350-400 mcM per 1 sq. m and a 1 second lamps on the basis of red and blue light-emitting diodes on density of a stream of photons in general provide adequate conditions of lighting for cultivation of many crops
Методика определения оптимального количественновозрастного состава тракторного парка
Get PDFFor self-restoration in an annual cycle of works of such resources as tractor fleet, an arable land and labor potential, it is necessary to define optimum quantitative and age structure of tractor fleet. If agricultural enterprises buy tractors less, than write off, their total fleet is reduced. Besides they use machines, which depreciation period expired long ago. The solution of this problem possibly at methodological approach. Cumulative cost minimization is linked to reduction of quantity of the tractors working in excess of depreciation period as such machines operation is interfaced to additional expenses and harvest losses. Besides, value of the missed profit as a result of losses from disposal of production resources, reduction of total number of tractor fleet, the area of an arable land, a shortfall in production, violation of agroterms and crop rotations increases. The authors developed a technique of definition of optimum quantitative and age structure of tractor fleet. They established influence of the main resources of the mechanized agricultural production on production cost. Criterion of optimization is the minimum of cumulative cost. The sum of an overspending for use of the tractors working in excess of depreciation period and the missed profit were estimated. The optimum quantitative and age structure of tractor fleet includes 310.3 thousand tractors aged up to 18 years
МЕТОДИКА ПОСТРОЕНИЯ ПРОФИЛЯ ПОПЕРЕЧНОГО СЕЧЕНИЯ ДИСКА
Get PDFA choice of the sizes and form of a disk is made for the set operation conditions on the basis of geometrical ratios between parameters of a disk and their admissible values developed by practice. Except the crumbling and turning ability of a disk the add factors influencing on its geometrical and power parameters are non-crumple condition of a vertical wall of a furrow and steady raising of layer on a curvilinear surface of operation sector. Basic data for construction horizontal, cross-vertical, longitudinal-vertical projections is diameter of a disk, an angle of attack, running depth. Depth of the course images a chord of disk dip on cross-vertical and longitudinal-vertical projections of a disk. The disk sphere which excludes crumple of a vertical wall of a furrow at its movement is designated on the horizontal projection. Criterion of disk efficiency a is possible soil sliding along a curve of longitudinal-vertical projection within limits of the lowermost point and a point excluding crumple of the furrow vertical wall and located on a chord of deep. The parameter of a curve of possible sliding can be defined taking into account that the sum of multiplications of tangent efforts to a projection of a trajectory of the movement of an elementary platform less than zero. Taking into account the received value we can construction the sliding curve on the longitudinal-vertical projection in a zone of operating surface. Points of intersection of the sliding curve with the generating lines of longitudinal-vertical projection are moved by horizontal transfer on a piece of an interval of the horizontal projection. On three points we create a profile of a disk on height of a placement of the generating lines. The disk profile with the spherical or flat bottom should be create at the level of generating lines of cross-vertical projection taking into account the intervals placed on a perpendicular to the center of diameter of a disk of a horizontal projection
Обоснование разработки технологического паспорта зерноуборочных комбайнов
Get PDFDynamics of grain crops productivity in the main grain growing regions of Siberian Federal District is presented. Major factors shoud be considered at justification of a class of combine harvesters for their effective operation in various climatic and working conditions. loading efficiency of a combine thresher depends on productivity and operating width of windrowers or headers at straight-cutting and windrowing. A tailings maintenance in the threshed grain heap influences on the harvester capacity. Certificate capacity of combines of a class of 5-12 kg/s at the 1.5 percent admissible level of losses behind a combine thresher is depending on the tailings maintenance in the threshed grain heap. In accordance to analysis the capacity of combines of any class of the classical design increases by 1.45 times at reduction of a straw content from 1.5 to 0.7 relative to standard indicators, and decreases by 1.16 times at increase of this parameter to 2.3. The combine of a class of 7 kg/s is completely loaded when pickup threshing by harvesters with a operating width of 20; 16 and 12 m at a speed of movement 7.2; 9.0 and 12.0 km/h respectively. The combine of a class of 10 kg/s at crop productivity of 1.8 t/ha will be completely loaded when pickup threshing if the operating width is 20 m and the speed equals 12 km/h, and at the width of 16 m speed has to make 13 km/h. The content of the technological certificate by the example of use of combines of a class of 7 kg/s (GS-07) and 10 kg/s (GS-10) is proved. The algorithm of determination of the movement speed is presented. Its use provides certificate loading of a thresher when threshing of grain crops with different productivity at straight-cutting and windrowing