نتایج جستجو برای: in particular work pressures
تعداد نتایج: 17052401 فیلتر نتایج به سال:
Since 1850, compressed-air work has been used to prevent shafts or tunnels under construction from flooding. Until the 1980s, workers were digging in compressed-air environments. Since the introduction of tunnel boring machines (TBMs), very little digging under pressure is needed. However, the wearing out of cutter-head tools requires inspection and repair. Compressed-air workers enter the pres...
in this study, a generalized equation is presented to calculate vapor pressure of pure substances as a function of reduced temperature, critical pressure, and acentric factor. with the presented model, vapor pressures have been calculated and evaluated with nist data bank for 70 pure substances for about 14000 data points, and the overall average absolute percentage deviation has been only 0.78...
any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...
in the present work, a simple and sensitive method was developed for determination of morphine and heroin using gold nanoparticles as resonance rayleigh scattering (rrs) and colorimetric technique’s probe. synthesized gold nanoparticles by sodium citrate reduction method have a negative charge layer on their surfaces because of self-assembled citrate anions on their surface. binding of morphin...
today, persian poetry is of great importance to many scholars around the world. the interest and attention of various cultures toward such a fine literature has given quite a good motivation for a comparative study. the major concern of the study is to investigate how nature is depicted through the works of the great english poet, william wordsworth (1770-1850) and the outstanding contemporary ...
abstract amino acids are building blocks of proteins, and play a vital role in living beings existence and their functionality. the interaction of these compounds with metal ions is of great importance to biochemists, and chemists, because their functions can be utilized as a model in understanding enzymes mechanism for transport of metal ions to tissues. among twenty essential amino acids w...
ii abstract the legend of human being’s refulgence was distorted completely in the age of modernity. this new age, had some drastic negative effects, besides its positive qualities. one significant negative effect of it was the emergence of neurosis in human beings. aldous huxley’s brave new world was one of the novels of the 02 th century that contained the prophecy of criticizing ...
The narrow operating window between pore pressure and fracture pressure makes drilling difficult in some operations. A feasibility study of managed pressure drilling (MPD) is carried out on Iran Darquain oil field. The previous wells drilled in this field showed that mud returns were lost during drilling Gadvan formation. The present work addresses this problem by means of surface back pressure...
In this work, experimental kinetics data of methane hydrate decomposition at temperatures ranging from 272.15 to 276.15 K and at pressures ranging from 10 to 30 bars were modeled by using chemical affinity. This model proposed a macroscopic model which is independent of any intermediate mechanism like heat or mass transfer. The results show there is good agreement with experimental data. Al...
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