PURPOSE Tizanidine is a clonidine derivative and has the same effects, such as sedation, anxiolysis and analgesic response. We evaluated the effect of tizanidine on infiltration pain during epidural catheterization. METHODS Forty patients scheduled to undergo epidural anesthesia in elective surgery were randomly allocated into two groups. The control group received placebo 60 minutes before a...

Continuous Flow Left Ventricular Assist Devices (CF-LVADs) generally operate at a constant speed, which causes a decrease in pulse pressure and pulsatility in the arteries and allegedly may lead to late complications such as aortic insufficiency and gastrointestinal bleeding. The purpose of this study is to increase the arterial pulse pressure and pulsatility while obtaining more physiological ...

Utilization of membrane humidifiers is one of the methods commonly used to humidify reactant gases in polymer electrolyte membrane fuel cells (PEMFC). In this study, polymeric porous membranes with different compositions were prepared to be used in a membrane humidifier module and were employed in a humidification test. Three different neural network models were developed to investigate several...

Very few reports have been presented to date on the noise and vibrational characteristics of oil injected screw compressors. This time. a series of extensive experimental analysis is performed. It includes the measurements and analysis of compressor casing vibrations. rotor shafts vibrations, torsional <rotational) vibrations. suction and discharge gas pulsations. pressure trans~ ient in one th...

Thermodynamic analysis of a novel combined system which is combination of methane fired gas turbine cogeneration system (CGAM) with a supercritical CO2 recompression Brayton cycle (SCO2) and an Organic Rankine Cycle (ORC) is reported. Also, a comprehensive parametric study is performed to investigate the effects on the performance of the proposed system of some important parameters. Finally, a ...

Microminiature pulse tube cryocoolers should operate at a frequency of an order higher than the conventional macro ones because the pulse tube cryocooler operating frequency scales inversely with the square of the pulse tube diameter. In this paper, the design and experiments of a high frequency pressure oscillator is presented with the aim to power a micropulse tube cryocooler operating betwee...

in this investigation, the performance of a tower for absorption of sulphur dioxide gas into calcium carbonate solution has been studied. the trays had no downcomer and the tower itself was a scaled down pilot from industrial equipment. the industrial scale tower was used for clean up of 110000 m3/hr gas using 40 m3/hr alkaline solution. the study was composed of two parts. in the first section...

black nightshade is a weed plant that grows abundantly in most parts of iran. in this study, central composite response surface method to investigate the effect of temperature 35-55 °c and pressures 170-350 bar during the dynamic time of 120 min, the particle size of 150 microns and flow rate of 3 liters per minute on the efficiency of oil extracted from the fruits of black nightshade and optim...

In the current research, ABS-co-PEG nanofiltration membrane was prepared by solution casting technique using N, N dimethyl acetamide as solvent. The effect of PEG concentration as additive in the casting solution on membrane flux, salt rejection, phase inversion time, water content, membrane porosity, membrane tensile strength and fouling was studied. Also the eff...