in this work, improved heat generation models are developed for straight and tapered shoulder geometries with different tool pin profiles in friction stir welding. the models are developed considering the welding process as a combination of the pure sliding and the pure sticking conditions. from the results, the amount of heat generation is directly proportional to the number of edges in the pi...

life table parameters of aphis pomi degeer (hemiptera: aphididae) were determined on two host plants: apple (malus pumila l.) and flowering quince (chaenomeles japonica lindl.). this study was carried out under laboratory conditions (25 ± 1 ºc and rh of 70 ± 5 % and a photoperiod of 16: 8 h (l: d). the survivorship from first instar nymphs to adult was very close in m. pumila and c. japonica. t...

in this paper, convection heat transfer of al2o3-water nanofluid turbulent flow through internally ribbed tubes with different rib shapes (rectangular, trapezoidal and semi-circular) is numerically investigated. for each rib shape, the optimum geometric ratio and volume fraction were calculated using entropy generation minimization technique. the governing equations in steady state and axisymme...

this paper presents an application of benders decomposition to deal with the complexities in the simultaneous generation expansion planning (gep) and transmission expansion planning (tep). unlike the power system operation fields of study, the power system planning methods are not expected to be fast. however, it is always preferable to speed up computations to provide more analysis options for...

The computer simulation program of a practical scale reverse electrodialysis process has been developed based on the program for saline water electrodialysis. The program is applied to compute the performance of an industrial-scale reverse electrodialysis stack (effective membrane area S = 1 m × 1 m = 1 m2, cell pair number N = 300 pairs). The stack operatingconditions are optimized. Seaw...

Electric power restructuring offers a major change to the vertically integrated monopoly. The change manifests the main part of engineers’ efforts to reshape the three components of today’s vertically integrated monopoly: generation, distribution and transmission. In a restructured environment, the main tasks of these three components will remain the same as before, however, to comply with ...

this paper presents a simplifiedlagrangian multiplier based algorithm to solve the fixed head hydrothermalscheduling problem. in fixed head hydrothermal scheduling problem, waterdischarge rate is modeled as quadratic function of hydropower generation andfuel cost is modeled as quadratic function of thermal power generation. thepower output of each hydro unit varies with the rate of water discha...

in this paper, the concept of conjectural variation (cv) is used to specify optimal generation decision for generation companies (gencos). the conjecture of genco is defined as its belief or expectation about the reaction of rivals to change of its output. using cv method, each genco has to learn and estimate strategic behaviors of other competitors from available historical market operation da...

through the last three decades different seismological and engineering approaches for the generation of artificial earthquakes have been proposed. selection of an appropriate method for the generation of applicable artificial earthquake accelerograms (aeas) has been a challenging subject in the time history analysis of the structures in the case of the absence of sufficient recorded accelerogra...