Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 7 Articles
This work describes the complete design of an olive picking machine especially conceived for secular olive plants\nwith the purpose of increasing the mechanization level of the harvest operation and permitting the production of high quality oil;\nthe design is made considering all the mechanical, agronomical and economical aspects involved in this issue. Once defined\nthe picking technique, the first step consists in the design of the shacking device used for the separation of the olives from the\nplant, the next step is the design of the support structure, including the arms and the frame; finally there is a description of the\nhydraulic plant that drives the moving parts of the machine; in order to increase the flexibility of the machine, it is adapted also\nfor other works, like pruning, that can be performed outside the harvest season. Starting from the principal characteristics of\nthe cultivations the design of the machine and its implementation is realized considering all functional features, including\nverifications of resistance according to the current standards; finally the economic aspects are hinted to confirm the marketing\nappeal of the machine...
In China, field management mechanization of corn, tobacco and sugarcane with high stalks is an important technical\nproblem in agricultural mechanization development. According to the characteristics of high stalk crops planted in different\nrow spacing in the plain area of Henan province, this paper designed a full hydraulic driving field high frame operation vehicle,\nincluded power system, engine placement and M type three-wheeled high frame structure. It also adopted a closed hydraulic\nsystem fully driven by three hydraulic motors, hydraulic power steering system and hydraulic track adjustment system. Its\nmaximum clearance height is 1,800 mm. Speed ranges from 0-17 km/h with the hydraulic control. The back wheel track\nadjustment ranges from 2,000-2,400 mm. It can solve the problems of the high cost price in complex transmission system of\nthe most domestic off highroad vehicles that the track cannot be changed. In this paper, a field high frame operation vehicle\nfor the high stalk crop in field management operation has been provided....
The morama bean (Tylosema esculentum) is an underutilised legume native to the Kalahari region of Southern\nAfrica. Some engineering properties relevant to the mechanisation of its processing have been characterised, namely; size,\nshape, surface area, projected area, volume, density, porosity, 1000-grain mass, static angle of repose, static coefficient of\nfriction and texture. At moisture content of 7.4% (w.b.), the average length, width and thickness of the beans were 19.25,\n17.21 and 13.39 mm, respectively. Geometric mean, equivalent diameter and arithmetic mean diameters were 16.4, 16.51 and\n16.61 mm, respectively. Morama beans are spherical in shape, having average sphericity of 85.45%, aspect ratio of 0.90 and\nflakiness ratio of 0.78. Surface area, projected area and volume of the beans were 850.43 mm2, 261.95 mm2 and\n2,352.82 mm3, respectively. Mean true and bulk densities were, respectively, 1,075.13 and 795.31 kg/m3 with bulk porosity\nderived as 25.76%. Mean 1000-grain mass was 2.21 kg. Static angle of repose was 12.98o, while static coefficient of friction\nof morama against plywood, galvanized iron, stainless steel, plastic, and itself, were 0.2, 0.26, 0.2, 0.18, and 0.24, respectively.\nTexture analysis by flat-plate compression testing showed that the beans required an average of 546.78 N to break and absorbed\nup to 470.03 mJ of energy before breaking, with hardness computed as 120.52 N/mm....
Long duration of cooking limits domestic consumption of African Yam bean (AYB) seed, an edible legume.\nReduction in energy demand during domestic cooking of AYB seed was the focus of the work. The seed was soaked in\nambient temperature, and also cooked to determine hydration curve. AYB seeds (153 g) were cooked using kerosene, electric,\nLiquefied Petroleum Gas (LPG), and charcoal stoves. Normal, control, open and pressure cooking were done. Cooking\nduration, energy consumed, water evaporation and cost were determined using standard procedures. Moisture content of the\nseed increased with soaking time while rate of water absorption decreased. Temperature significantly (p<0.05) influenced\nboth moisture content and water absorption rate. Energy consumption varied with methods of cooking regardless of energy\nsource. Pre-soaked control pressure cooked method consumed least energy using kerosene (4,849.7 kJ), electric (3,085 kJ),\nand LPG (2,673 kJ) stoves. Pre-soaked pressure control electric cooking method was the cheapest energy source (US $0.071),\nalthough not significantly different from pre-soaked pressure control LPG (US $0.075). While un-soaked open normal\nkerosene method was most expensive (US $0.342). Shortest cooking time of 55 minutes was recorded in pre-soaked pressure\nnormal electric stove while un-soaked open control LPG method duration of 170 minutes was the longest. Opening and\nclosing of pot majorly determined the energy loss due to evaporation. Generally, controlled energy input, cooking at high\npressure, and soaking of AYB seeds before cooking independently reduced the energy required for cooking....
In this paper, fourteen standard models were used to estimate the moisture ratio of three varieties of bean in Iran\n(Talash, Sadri and Mahali Khomein). The experiments were carried out using distilled water at three temperatures (5�°C, 25�°C\nand 45�°C) and three replicates. The standard models of water absorption were fitted to the experimental data. To evaluate\nthe models, three parameters: coefficient of determination (R2), chi-square (?2) and root mean square error (RMSE) were used.\nThe appropriate model was chosen based on maximum value of coefficient of determination and minimum value of chi-square\nand root mean square error. The effective moisture diffusivity coefficient of three verities in each temperature was estimated\nby Fickâ��s equation. The result demonstrated that the Weibull model is the most appropriate for each variety in three\nexperimental temperatures to estimate moisture ratio changes versus time in soaking. Thus, moisture ratio versus time was\nplotted for each case, using Weibull equation. The plotted curves of each variety of bean indicated that moisture ratio\ndecreases with increase in temperature. Besides that, the effective moisture diffusivity coefficient of three verities increased in\nresponse to increasing temperature from 5 - 45�°C....
The drying process of turnip and drying rate curves were investigated at different temperatures (55, 70 and 85Ã?°C)\nwith air flow rate of 1.5 m/s. Also effective diffusion coefficient and activation energy were calculated by using Arrhenius\nequation and Fickââ?¬â?¢s second law for infinite slab. The effective diffusivity varied between 5.471Ã?â??10-10 and 8.966Ã?â??10-10 in the\nrange of (55Ã?°C to 85Ã?°C). The value of activation energy was found to be 16.013 kJ/mol. The mathematical models (Newton,\nPage, Modified Page, Henderson and Pabis, Logarithmic, Two term, Two term exponential, Wang and Singh, Simplified Fickââ?¬â?¢s\ndiffusion, Modified Page ââ?¬â??II, Verma, Midilliââ?¬â??Kucuk, Hii, Law and Cloke, Approximation of diffusion, Modified Henderson\nand Pabis) were fitted to the experimental data. Sigmaplot v10.0 software was used to find the best model for evaluating the\nrate of moisture change. Decency of fit by these models was based on comparing the coefficient of determination (R2),\nreduced chi-square (?2), mean bias error (MBE) and root mean square error (RMSE) between the observed and predicted\nvariables. Among 15 evaluated models, Modified Henderson and Pabis in 85Ã?°C and Hii, Law and Cloke in 55Ã?°C and 70Ã?°C\nwith highest R2 and lowest MBE, ?2 and RMSE were selected to better estimate the drying curves....
An approach to developing variable-rate sprayer technologies is to install electronic control systems on conventional\nsprayers. This study introduces a direct injection type electronic solution concentration control system. This control system\nwas installed on a field sprayer, and then a map-based variable-rate sprayer was developed. The control system consisted of a\nchemical tank, a chemical metering pump, the metering pump�s driver, the metering pump�s speed sensor, the implement�s\ntravelling speed sensor, an Electronic Control Unit (ECU), a GPS receiver and a mixing unit. The metering pump discharge\nwas measured at different carrier liquid (water) working pressures (3, 4 and 5 bar) and different chemical metering pump shaft\nspeed (100, 200, 300 and 400 r/min, i.e. pump�s working range). Data analysis showed that the effect of metering pump speed,\nsprayer working pressure and their interaction was significant (P<0.001) on the metering pump�s discharge. Metering pump�s\ndischarge function and the independent variables of pump speed and working pressure were calculated. In order to determine\nthe system response time, an electromotor replaced on the right hand front wheel of the tractor (the implement�s traveling speed\nsensor location), thus simulating the implement�s movement. An Electrical Conductivity (EC) sensor was mounted on\nrightmost nozzle of the boom. The chemical tank was filled with thick brine. The system response time was measured at\ndifferent working pressures (3, 4 and 5 bar), travelling speeds (3, 6 and 9 km h-1) and spraying concentration change rates (2, 3\nand 4 L ha-1). The working pressure was the only variable with a significant effect on the response time at the 1% level. The\nmean of response times were 25.8, 22.8 and 17.9 s at 3, 4 and 5 bar working pressures, respectively. The look-ahead firmware\nof the system was designed using the determined response time....
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