photocatalytic reduction of carbon dioxide to formaldehyde was investigated on four semiconductor photocatalysts (fes, fes/fes2, nio and tio2). the reaction was carried out in continues flow of co2 gas bubbled into the reactor. semiconductor photocatalysts were characterized by x-ray diffraction (xrd) and diffuse reflectance spectroscopic (drs) methods. sulfide ion was used as hole scavenger. t...

Exergy analysis and response surface methodology (RSM) is applied to reduce the exergy loss and improve energy and exergy efficiency of acetic acid production plant. Exergy analysis is run as a thermodynamic tool to assess exergy loss in reactor and towers of acetic acid production process. The process is simulated in Aspen Plus(v.8.4) simulator and the necessary thermodynamics data for calcula...

in this paper, the static var compensator (svc) has been used to improve dynamic behaviour of power system. to do this, a new objective function is formulated considering power loss reduction, voltage profile improvement and loadability margin decrease. other contribution of this research is proposing a novel structure for particle swarm optimization (pso) algorithm through modifying the initia...

this study on the design of pid controllers for flexible single-arm robot system optimizationpso method is focused so that the coefficients of the pid controller are reduced. in this study,pid controller and pso algorithm have been described and then by using matlab, pidcontrol was simulated. then by pso algorithm, attempts to reduce the pid coefficients are givenby simulation. finally pid coef...

Electrical steels are important alloys widely used in electrical instruments. The magnetic properties and low core loss of grain oriented silicon steels are closely related to the sharpness of Goss texture ({110} ).The direction of is the softest direction for magnetism.  In this work, the microstructure and dependence of orientation density along the major texture fibers on the applied cold ro...

paleolithic lithic assemblages are traditionally described on the bases of presence of a variety of tool types(typology) and of different knapping technologies. in this study we tried to investigate whether the presence ofdifferent groups of scrapers in the mar-tarik site assigned to the middle paleolithic represent specific function orjust different stages of the reduction process and constant...

climate change phenomenon is an important environmental challenge of the world. increasing extension of greenhouse gases and remote relationship phenomena accelerate the speed f climate change. changes in precipitation level, drought occurrence and changes in the level of surface and groundwater resources are the recognized consequences of climate change. in order to study consequences of clima...