Activated dissociative chemisorption of methane on Ni(100): a direct mechanism under thermal conditions?

1995 ◽  
Vol 32 (1-2) ◽  
pp. 15-30 ◽  
Author(s):  
B. �lgaard Nielsen ◽  
A. C. Luntz ◽  
P. M. Holmblad ◽  
I. Chorkendorff
Keyword(s):  
Thermal Conditions ◽  
Dissociative Chemisorption ◽  
Direct Mechanism

The Interrelationship between Thromboxane Biosynthesis, Aggregation and 5-Hydroxytryptamine Secretion in Human Platelets in Vitro

1980 ◽  
Vol 43 (01) ◽  
pp. 038-040 ◽  
Author(s):  
L C Best ◽  
T K Holland ◽  
P B B Jones ◽  
R G G Russell
Keyword(s):  
Human Platelet ◽  
Human Platelets ◽  
Dense Granule ◽  
Thromboxane B2 ◽  
Essential Requirement ◽  
Direct Mechanism ◽  
Thromboxane Synthetase ◽  
Thromboxane Production ◽  
Higher Doses

SummaryPlatelet aggregation, secretion of 5-hydroxy tryptamine and production of thromboxane B2 were monitored simultaneously in human platelet suspensions in the absence and presence of cyclooxygenase or thromboxane synthetase inhibitors. Aggregation, secretion and thromboxane B2 formation in response to either sodium arachidonate or epinephrine were blocked by aspirin or by 1-N-butyl imidazole suggesting that thromboxane biosynthesis was an essential requirement for platelet activation by these agents. In contrast, thrombin and collagen could apparently induce aggregation and secretion via two pathways: at low doses involving thromboxane production, but at higher doses by a direct mechanism independent of thromboxane biosynthesis. In the case of ADP, inhibition of thromboxane production blocked secretion but had little effect on aggregation, indicating that secretion was probably dependent on thromboxane biosynthesis which probably occurred as a result of aggregation. Thus it appears that although the processes of thromboxane production, release of dense granule constituents and aggregation may often be intimately linked, each process can occur independently of the other, depending upon the stimulus used.

Research and Modelling on Electrical and Thermal Mode of LEDs Operation in the Luminaire

2018 ◽  
pp. 155-162 ◽  
Author(s):  
Sergei S. Kapitonov ◽  
Anastasia V. Kapitonova ◽  
Sergei Yu. Grigorovich ◽  
Sergei A. Medvedev ◽  
Taher Sobhy
Keyword(s):  
Thermal Conditions ◽  
Operating Mode ◽  
Thermal Processes ◽  
Thermal Mode ◽  
Crystal Temperature ◽  
Premature Failure ◽  
Model Based

In the article, the electrical and thermal processes in the LED lamp with varied parameters are investigated. Voltage and current measurements on all LEDs of the luminaire are carried out in the nominal operating mode. The power allocated to each LED is determined. The calculation of the LED crystal temperature was carried out using the developed thermal LED model based on the results of the measurements and by using “Multisim” program. It has been established that the temperature of the crystals of individual LEDs in the luminaire differ significantly, which leads to unfavourable thermal conditions for them and an increased likelihood of premature failure.

Tendencies of climatic changes for thermal conditions in the coastal areas of the Okhotsk Sea in last decades

2017 ◽  
Vol 191 ◽  
pp. 176-195 ◽  
Author(s):  
Igor D. Rostov ◽  
Elena V. Dmitrieva ◽  
Alexander A. Vorontsov
Keyword(s):  
Thermal Conditions ◽  
Climatic Changes ◽  
Coastal Areas ◽  
Okhotsk Sea

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

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