检索结果-南通市图书馆

An approach of the internal friction-dependent temperature changes for conventional and pure biogenic lubricating greases

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 780-795页

作者： Leif AHME Erik KUHN MiguelÁngel DELGADO Department of Mechanical Engineering and Production Management Hamburg University of Applied SciencesHamburg 20099Germany Department of Chemical Engineering Research in Product Technology and Chemical Processes(Pro2TecS)University of HuelvaHuelva 21071Spain

This work investigated the temperature changes inside the bulk of lubricating greases under controlled high-shear stress conditions(250-500 s-1).For this purpose,a newly developed temperature-measuring cell called Calidus was successfully *** temperature changes(ΔT)have been related to the greases'components(thickener,base oil-type,and composition)and the structural degradation of the lubricating ***,a theoretical approach was proposed for calculating the internal temperature change of lubricating greases during shear *** greases showed an internal temperature profile characterised by a sudden rise inΔT within the first 4 h from starting the test and subsequentΔT decay until it reaches the steady state ***,it was found that greases C1 and C5,formulated with lithium and calcium soap,respectively,with different soap content(16.1 wt%and 9.7 wt%,respectively),but the same base castor oil,showed the highest value of the maximumΔT,c.a.3.2 K,and the most drastic drop ofΔ*** greases showed both the highest specific densities and heat *** addition,they showed the lowest ratio of expended energies(Rtee),which means more structural degradation in the stressed *** the contrary,the grease C3,with 13 wt%of Li-soap but the lowest base oil's viscosity,showed the lowest maximumΔT and the temperature profile was characterised by a moderate variation ofΔT along the *** biogenic grease B3 developed a low-temperature change in the group of pure bio-genic greases close to grease C3.

关键词： shear-induced structural degradation rheology temperature measurements lubricating greases density lubricating greases specific heat capacities

On the Thermal Distribution in Oncological Hyperthermia Treatments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Biophysics 2024年第2期14卷 239-263页

作者： Andras Szasz Department of Biotechnics Hungarian University of Agriculture and Life Sciences G&#246d&#246ll&#337 Hungary

The temperature is one of the principal controlling parameters of oncological hyperthermia. However, local heating forms a complicated thermal distribution in space and has developed over time, too. The decisional factors are the heterogeneity of the targeted volume, the electrolyte perfusions controlled by thermal homeostasis, and the spreading of the heat energy with time. A further complication is that the energy absorption sharply changes by depth, so the spatiotemporal development of the temperature distribution requires specialized methods to control. Most of the temperature imaging facilities (thermography, radiometry, electric impedance tomography, etc.) are less precise than the medical practice needs. In contrast, precise point sensing (like thermocouples, thermistors, and fluoroptical methods) is invasive and measures only a discrete point in the robustly changing thermal map. The two most precise thermal imaging methods, computer tomography, and magnetic resonance are expensive and have numerous technical complications. Our objective is to show the complexity of the temperature distribution inside the human body, and offer a relatively simple and cheap method to visualize its spatiotemporal development. A novel emerging technology, the application of ultrasound microbubble contrast agents is a promising method for solving complicated tasks of thermal distribution deep inside the living body. Noteworthy, the temperature distribution does not determine the full hyperthermia process, nonthermal effects make considerable impact, too. Additionally to the difficulties to measure the thermal heterogeneity during hyperthermia in oncology, numerous nonthermal processes, molecular and structural changes are triggered by the incoming electromagnetic energy, which presently has no spatiotemporal visualization technique. Microbubble imaging has a suitable spatiotemporal thermal resolution, and also it is sensitive to nonthermal effects. Its application for characteri

关键词： Microbubbles Thermal Heterogeneity Electric Heterogeneity Bloodstream Thermal and Nonthermal Synergy temperature Distribution temperature measurements

The Real Origin of Climate Change and the Feasibilities of Its Mitigation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Climate Sciences 2023年第3期13卷 353-384页

作者： Thomas Allmendinger Glattbrugg Switzerland

The actual treatise represents a synopsis of six important previous contributions of the author, concerning atmospheric physics and climate change. Since this issue is influenced by politics like no other, and since the greenhouse-doctrine with CO2 as the culprit in climate change is predominant, the respective theory has to be outlined, revealing its flaws and inconsistencies. But beyond that, the author’s own contributions are focused and deeply discussed. The most eminent one concerns the discovery of the absorption of thermal radiation by gases, leading to warming-up, and implying a thermal radiation of gases which depends on their pressure. This delivers the final evidence that trace gases such as CO2 don’t have any influence on the behaviour of the atmosphere, and thus on climate. But the most useful contribution concerns the method which enables to determine the solar absorption coefficient βs of coloured opaque plates. It delivers the foundations for modifying materials with respect to their capability of climate mitigation. Thereby, the main influence is due to the colouring, in particular of roofs which should be painted, preferably light-brown (not white, from aesthetic reasons). It must be clear that such a drive for brightening-up the World would be the only chance of mitigating the climate, whereas the greenhouse doctrine, related to CO2, has to be abandoned. However, a global climate model with forecasts cannot be aspired to since this problem is too complex, and since several climate zones exist.

关键词： IR-Absorption of Gases Thermal Radiation of Gases Solar Absorption Coefficient of Coloured Bodies Albedo temperature measurements

Effect of temperature on Polaron Stability in a One-Dimensional Organic Lattice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2009年第3期26卷 196-199页

作者：刘文李元渠朕高琨尹笋刘德胜 State Key Laboratory of Crystal Materials School of Physics Shandong University Jinan 250100 Department of Physics Jining University Qufu 273155

Effect of temperature on the polaron stability in a one-dimensional organic lattice is investigated within the Su-Schrieffer-Heeger model. The temperature effect is simulated by introducing random forces to the equation of the lattice motion. It is found that the localized polaron state becomes delocalized even at low temperatures. The time of polaron keeping localized depends on the magnitude of temperatures. By taking into account the thermal effect, we find that the dissociation field is weaker as compared with earlier works.

关键词： POLARONS DYNAMICS of a particle temperature effect LATTICE theory temperature measurements EQUATIONS of motion

Maximal Heat Generation in Nanoscale Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2009年第3期26卷 234-235页

作者：周利玲李树深曾朝阳 State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 Department of Physics diangxi Normal University Nanchang 330022

We investigate the heat generation in a nanoscale system coupled to normal leads and find that it is maximal when the average occupation of the electrons in the nanoscale system is 0.5, no matter what mechanism induce... 详细信息

关键词： NANOELECTROMECHANICAL systems ELECTRIC machinery -- Thermodynamics temperature measurements ELECTRONS MAXIMA & minima