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Pulse width modulation (PWM) has been used to alter the performance of on-off hydraulic control valves to make them perform as proportional type flow control valves. Nonlinear performance resulting from time delays in valve switching as well as valve wear due to continuous cycling continue to persist as operational problems. This paper examines a new technique called modified PWM control. The method was found to provide accurate control with a minimum of valve chatter.

A new prototype of a single unit till-planting system suitable for Egyptian soil was designed, constructed, and tested under soil bin and field conditions. Measurements were taken for draft, soil mean weight diameter, and seedling emergence. Results indicated that there are potential benefits of using this system rather to other tillage systems under dry and hard soil conditions. An optimum seedbed was created for rapid seedling emergence. Combinations of tillage, planting, and fertilizer application were performed in a single operation to reduce power and time requirements for crop production.

This work is based on comparative study of oilseed flax fibre and glass fibre reinforced composite boards for potential application in automotive industries. The material characterizations of flax and glass fibre-composites using unsaturated polyester as matrix were evaluated. Vacuum infusion was used for fabrication of composites. Flexural, tensile, water absorption and color tests were conducted on the composite boards. The density and the moisture content of flax/glass fibre mats were also measured. Three types of composite boards, including flax, glass and flax-glass sandwich were developed and characterized.

Flax, which is known for its linens and oils that are used for industrial products, can also be utilized as a cost effective and environmentally acceptable approach to the creation of a partially biodegradable biocomposite. Biocomposite material is investigated by combining recycled tire rubber, flax and linear low density polyethylene (LLDPE). The manufacturing process which be used to fabricate the biocomposite product included Extrusion and Compression Molding. Optimizing and studying the composition percentages of the compounds were studied in this paper. Moreover, the properties of the product were observed by using tensile test, tearing test, water absorption test, hardness test and Differential Scanning Calorimetry.

The agricultural combine harvester is one of the most complex of machines used in cereal grain production. It is believed that significant increases in efficiency and productivity could be realized if several of the machine adjustments could be automatically controlled. One of the most important parameters to measure and control is the feedrate, i.e. the mass flow rate of material entering the machine. This paper reports on an investigation of a sensor, using electrical capacitance techniques, to measure feedrate.

Understanding the Relationships between plants and soil is important in the development of methods of crop production. Although physical properties of soil conducive to plant growth can be recognized by experienced observers, many of these properties have not been defined satisfactorily in mathematical or physical terms. A method of measuring penetration resistance and energy exerted by a mechanical seedling (a steel probe simulating a seedling) as it moved upward through the soil surface under different levels of surface compaction and soil moisture was examined. Mechanical seedlings with 2.06, 3.19 and 4.65 mm tip diameters were tested at soil moisture levels of 13, 17, and 20%. The penetration rate of the mechanical seedling while moving through the soil was held constant at 10 mm/min. Results showed that the emergence energy increased directly with soil surface compaction pressure, initial soil moisture content, and mechanical seedling diameters.