farm machinery managers often need to make complex economic decisions on machinery replacement. repair and maintenance costs can have significant impacts on this economic decision. the farm manager must be able to predict farm machinery repair and maintenance costs. this study aimed to identify a regression model that can adequately represent the repair and maintenance costs in terms of machine...

Feedforward and multiple-feedback A/D converters offer high-resolution, but are susceptible to instability in the presence of capacitor tolerances in a corresponding switchedcapacitor (SC) hardware implementation. The hitherto A/D converters are usually based on, a) complementary signal and noise transfer functions, and/or b) unitcircle noise transfer function zeros. This paper is concerned wit...

This paper proposes a matrix converter based unified power quality conditioner (MC–UPQC) for mitigating power quality problems. This proposed system is a combination of unified power quality conditioner and matrix converter. The UPQC is a combination of back-toback connected series and shunt active filters through a dclink. Voltage disturbances and harmonics are compensated by series active fil...

Averaging networks suppress the random mismatch between the comparators in flash A/D converters (ADCs), but an analytical understanding does not exist, nor a method for optimal design. This paper unifies various forms of offset averaging and derives the optimum by treating the averaging network as a spatial filter. At the optimum, the offsets in terms of LSB are minimized with almost no loss in...

To improve the low speed performance of the direct torque control(DTC) system. The advantages of DTC method are combined with the advantages of the matrix converter based on space vector modulation technique. The design process of the neural network controller which generating the flux reference voltage vector and fuzzy controller which applying the torque reference voltage vector were represen...

in this paper the use of farm machinery in sugar beet farms in farsprovince was studied. the necessary data, with two-stage cluster sampling method in fasa, eghlid and darab cities on 2004- 2005 were collected. from 203 farmers selected for the study. 113 of them were in high level mechanization group and 90 of them were in low level mechanization group. in this study, the effect of farm machin...