We have investigated the pressure dependence of the detection sensitivity of CO(2), N(2)O and CH(4) using wavelength modulation spectroscopy (WMS) with distributed feed-back diode lasers in the near infrared region. The spectral line shapes and the background noise of the second harmonics (2f) detection of the WMS were analyzed theoretically. We determined the optimum pressure conditions in the...

The study was conducted to develop castor oil – graphite lubricants for cold extrusion of aluminium alloy and to investigate the effect of the developed lubricant on the extrusion pressure of aluminium alloy. Cold extrusion process at a constant extrusion ratio of 1.25:1 was used on 14mm diameter by 30mm long aluminium alloy billets. Experimental results showed that onset pressure ranges from 1...

We experimentally studied the dependence of high harmonic generation in argon and molecular hydrogen on pressure changes in a gas jet that cause variations of the phase matching conditions and absorption. The study was performed at a peak laser intensity of ∼1.5 × 10(14) W/cm(2). To enable measurements over a wide range of pressures, we employed differential pumping with an additional cell (∼20...

in this paper, a new model based on kinetic theory of gases and longitude oscillations of metallic nanocluster on single carbon nanotube (cnt) in addition to phononvibrations of cnt on substrate is presented to describe the growth mechanism of ultra-long cnt in chemical vapor deposition (cvd).interaction between cnt and catalyst is investigated by lennard-jones potential. simulations demonstrat...

Optimization of drilling fluid parameters such as mud weight, salt concentration, and temperature is essential to alleviate instability problems during drilling through shale sections. The selection of suitable mud parameters can benefit from analyses that consider significant instability processes involved in shale-drilling–fluid interactions. This paper describes the development of analytical...

The present work analyses different parameters of pressure die casting to minimize the casting defects. Pressure diecasting is usually applied for casting of aluminium alloys. Good surface finish with required tolerances and dimensional accuracy can be achieved by optimization of controllable process parameters such as solidification time, molten temperature, filling time, injection pressure an...

The optimal design of a plate-fin recuperator of a 200-kW microturbine was studied in this paper. The exergy efficiency, pressure drop and total cost were selected as the three important objective functions of the recuperator. Genetic Algorithm (GA) and Non-dominated Sorting Genetic Algorithm (NSGA-II) were respectively employed for single-objective and multi-objective optimizations. By opt...