An efficient numerical method for the design and synthesis of compensator for a relay type control system is developed and discussed. Previous works based on the interactive graphic method are reviewed and it is shown that the combination of the trequency and time domain numerical techniques provide a powerful tool in design of a wide class of relay control systems. An example is presented to d...

Introducing cover crops is a form of ecological intensification that can potentially reduce local, regional and global environmental impacts soybean cropping systems. An assessment multiple (global warming potential, eutrophication, soil erosion organic carbon variation) was performed on continuous system in the U.S. upper Midwest. Four sequences were assessed compared: with winter camelina, fi...

In this paper, a cooperative algorithm to improve the orthogonal space-timefrequency block codes (OSTFBC) in frequency selective channels for 2*1, 2*2, 4*1, 4*2 MIMO-OFDM systems, is presented. The algorithm of three node, a source node, a relay node and a destination node is formed, and is implemented in two stages. During the first stage, the destination and the relay antennas receive the sym...

The restricted earth fault (REF) relay is a type of differential protection which is used for detection of internal ground faults of power transformers. But, during external faults and transformer energization conditions, the probability of current transformer (CT) saturation increases. Thus, the spurious differential current due to CT saturation, can lead to REF relay maloperation. In this pap...

A series of field experiments was conducted at BARI central farm to observe the changes in soil densities, moisture retentive properties, and crop productivity as influenced by different tillage depths and cropping patterns. The tillage depth showed significant effect on wheat yield. Grain yield of wheat significantly increased from 2.86 t/ha (minimum tillage depth) to 5.33 t/ha (tillage depth ...

Most studies of the influence of weather and climate on food production have examined the influence on crop yields. However, climate influences all components of crop production, includes cropping area (area planted or harvested) and cropping intensity (number of crops grown within a year). Although yield increases have predominantly contributed to increased crop production over the recent deca...

Agricultural sustainability has become a major concern in arid regions of China. In order to better understand the influence of continuous cropping on soil quality, six experimental fields were established in the Alar Oasis of Xinjiang, including uncultivated land (as a zero year treatment duration) and five different continuous cropping years on cotton fields, with different cropping durations...

Cropping is a cutting process whereby opposing aligned blades create a shearing failure by exerting opposing forces normal to the surfaces of a metal sheet or plate. Building on recent efforts to quantify cropping, this paper formulates a plane strain elastic–plastic model of a plate subject to shearing action by opposing rigid platens. Shear failure at the local level is modeled by a cohesive ...

The effect of cropping system on the distribution of organic carbon (OC) and nitrogen (N) in soil aggregates has not been well addressed, which is important for understanding the sequestration of OC and N in agricultural soils. We analyzed the distribution of OC and N associated with soil aggregates in three unfertilized cropping systems in a 27-year field experiment: continuously cropped alfal...