scholarly journals 10.5937/zeint24-6824 = Experimental investigations of mineral and ester-based oils at low temperature

Author(s):  
Milos Andjelkovic ◽  
Dragan Djordjevic
2003 ◽  
Vol 2 (3) ◽  
pp. 56-61
Author(s):  
B. I. Alperovich ◽  
A. V. Potapov ◽  
V. N. Salo

The aim of the investigation – to study changes in hepatic tissue resulting from the influence of low temperatures (– 195,8 °C) in experiments and clinic. Hepatic tissue investigations in experiment have been carried out using electron and light microscopy. During the surgery instruments of original design have been used – cryoscalpels and cryodestructors. Experiments have been carried out on 45 sexually mature dogs of both sexes. Animals have been separated into 3 groups. On the first group (consisting of 12 animals), in the acute experiment, there have been studied features of cryoscalpel design characteristics. In the second series of experiment (on 22 dogs) there have been made a comparative study of hepatic resection using cryoultrasonic scalpel and simple surgical scalpel by means of the study of hemorrhage quantity. In 11 cases there have been studied hepatic morphological changes affected by cryoeffect. By the effect of low temperature ice crystals are appeared in hepatic tissue intracellularly and outside the cell, they cause mechanical injury and rupture of hepatic tissue. In 45 days connective tissue elements are formed at the place of cryodestruction. The use of cryoultrasonic scalpel in hepatic resection in the experiment decreases the hemorrhage quantity by 1,26 times as compared to the traditional methods. Positive experimental investigations allowed to use the low temperature with success in clinical practice at 253 patients with different localized hepatic diseases with 13 lethal outcomes (5,1%). Thus, the used cryosurgical technique during surgical operations allows to decrease significantly the hemorrhage, to eliminate parenchymatous bleeding and to prevent relapses of disease both at growths and at parasitic hepatic affection.


2006 ◽  
Vol 361 (1474) ◽  
pp. 1715-1720 ◽  
Author(s):  
M Anand ◽  
S.S Russell ◽  
R.L Blackhurst ◽  
M.M Grady

Recent spacecraft and lander missions to Mars have reinforced previous interpretations that Mars was a wet and warm planet in the geological past. The role of liquid water in shaping many of the surface features on Mars has long been recognized. Since the presence of liquid water is essential for survival of life, conditions on early Mars might have been more favourable for the emergence and evolution of life. Until a sample return mission to Mars, one of the ways of studying the past environmental conditions on Mars is through chemical and isotopic studies of Martian meteorites. Over 35 individual meteorite samples, believed to have originated on Mars, are now available for lab-based studies. Fe is a key element that is present in both primary and secondary minerals in the Martian meteorites. Fe-isotope ratios can be fractionated by low-temperature processes which includes biological activity. Experimental investigations of Fe reduction and oxidation by bacteria have produced large fractionation in Fe-isotope ratios. Hence, it is considered likely that if there is/were any form of life present on Mars then it might be possible to detect its signature by Fe-isotope studies of Martian meteorites. In the present study, we have analysed a number of Martian meteorites for their bulk-Fe-isotope composition. In addition, a set of terrestrial analogue material has also been analysed to compare the results and draw inferences. So far, our studies have not found any measurable Fe-isotopic fractionation in bulk Martian meteorites that can be ascribed to any low-temperature process operative on Mars.


2016 ◽  
Vol 18 (42) ◽  
pp. 29286-29292 ◽  
Author(s):  
Qingyong Meng ◽  
Kevin M. Hickson ◽  
Kejie Shao ◽  
Jean-Christophe Loison ◽  
Dong H. Zhang

The O(1D) + CH4 rates from RPMD and VUV-LIF are close to each other in the temperature range of the atmosphere.


Author(s):  
AD Badgujar ◽  
MD Atrey

The design of a highly efficient pulse tube cryocooler (PTC) is a subject of recent research activities. The PTC performance depends on various operating and design parameters. Regenerator is one of the very important components of the PTC which decides the low temperature that the PTC can attain. Efficiency of regenerator should be high enough, 96% or above, in order to reach very low temperature while the pressure drop in the regenerator is one of the parameters which needs to be analysed in detail. In the present work, theoretical and experimental investigations are carried out on two different single stage U type PTC. The volumes of regenerators and pulse tubes, in both the cases are kept same while the length to diameter (L/D) ratios of regenerators are changed. Investigations are carried out on these PTC with respect to pressure drop in the regenerator and net refrigeration effect obtained from the PTC at 80 K. The pressure drop increases from 0.29 bar to 2.07 bar with an increase in L/D ratio from 1.93 to 9, resulting in decrease in refrigeration effect from 6.1 W to 1.7 W at 80 K with 300 W input power. The study is further extended to understand the effect of coarse size stainless steel mesh size in the regenerator. Coarse size meshes filled up to 60% of regenerator length improved the refrigeration effect from 1.7 W to 2.8 W; however, further filling degrades the performance of the PTC. The experimental results are compared with theoretical results obtained by Sage software and Isothermal model.


Author(s):  
Johannes Eichmeier ◽  
Uwe Wagner ◽  
Ulrich Spicher

The simultaneous reduction of fuel consumption and pollutant emissions, namely NOx and soot, is the predominant goal in modern engine development. In this context, low temperature combustion concepts are believed to be the most promising approaches to resolve the above mentioned conflict of goals. Disadvantageously these combustion concepts show high peak pressures or high rates of pressure rise due to early ignition and high reaction rates especially at high loads. Furthermore, there are still challenges in controlling combustion phasing. In this context using a small amount of pilot Diesel injected directly into the combustion chamber to ignite a highly diluted gasoline air mixture can overcome the aforementioned difficulties. As the gasoline does not ignite without the Diesel, the pilot injection timing can be used to control combustion phasing. By increasing dilution even high loads with low rates of pressure rise and without knocking are possible. This paper shows the results of experimental investigations carried out on a heavy duty boosted single cylinder Diesel engine. Based on the indicated cylinder pressure, the combustion process is characterised by performing knock analyses as well as thermodynamic analyses. Furthermore an optically accessible engine has been set up to investigate both the Diesel injection and the combustion process by means of digital high speed imaging. Together with the thermodynamic analyses the results of these optical investigations make up the base for the presented theoretical model of this combined Diesel gasoline combustion process. To show the load potential of this Dual-Fuel-CAI concept, the engine was operated at 2100 1/min with an IMEP of 19 bar. NOx emissions did not exceed 0.027 g/kWh.


2014 ◽  
Vol 39 ◽  
pp. 196-209 ◽  
Author(s):  
Dariusz Butrymowicz ◽  
Kamil Śmierciew ◽  
Jarosław Karwacki ◽  
Jerzy Gagan

2011 ◽  
Vol 487 ◽  
pp. 113-115
Author(s):  
Z.M. Cui ◽  
J.P. Kong ◽  
X.P. Yang ◽  
Lei Du

Ceramic hollow ball Super hard composite abrasive has spherical hollow Mini-bore structure, This article introduced the structure of hollow spherical super hard abrasive, grinding model and the experimental investigations were conducted, It is found that the grinding wheel with hollow ball Super hard composite abrasive has more holes in the working layer of grinding wheel and can carrying more cooling fluid into the grinding area for heat exchanges, thus reducing the grinding temperature.


Author(s):  
Yoshiharu Amano ◽  
Keisuke Kawanishi ◽  
Takumi Hashizume

This paper reports results from experimental investigations of the dynamics of an ammonia-water mixture turbine system. The mixture turbine system features Kalina Cycle technology [1]. The working fluid is an ammonia-water mixture (AWM), which enhances the power production recovered from the low-temperature heat source [2], [3]. The Kalina Cycle is superior to the Rankine Cycle for a low temperature heat source [4], [5]. The ammonia-water mixture turbine system has distillation-condensation processes. The subsystem produces ammonia-rich vapor and a lean solution at the separator, and the vapor and the solution converge at the condenser. The mass balance of ammonia and water is maintained by a level control at the separator and reservoirs at the condensers. Since the ammonia mass fraction in the cycle has a high sensitivity to the evaporation/condensation pressure and vapor flow rate in the cycle, the pressure change gives rise to a flow rate change and then level changes in the separators and reservoirs and vice versa. From the experimental investigation of the ammonia-water mixture turbine system, it was observed that the sensitivity of the evaporating flow rate and solution liquid density in the cycle is very high, and those sensitivity factors are affected by the ammonia-mass fraction. This paper presents the experimental results of a study on the dynamics of the distillation process of the ammonia-water mixture turbine system and uses the results of investigation to explain the mechanism of the unstable fluctuation in the system.


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