Effect of Temperature Dependence of the Langmuir Constant Molecular Pair Potentials on Gas Hydrates Formation Mechanism

2008 ◽  
Author(s):  
B. Mokhtari ◽  
M. Enayati ◽  
E. Heidaryan
Keyword(s):  
Temperature Dependence ◽  
Formation Mechanism ◽  
Gas Hydrates ◽  
Effect Of Temperature ◽  
Molecular Pair ◽  
Pair Potentials

scholarly journals Temperature Dependence of Limiting Fluorescence Anisotropy of POPOP in Cellulose Acetate Film

1985 ◽  
Vol 40 (6) ◽  
pp. 559-561
Author(s):  
A. Kawski ◽  
A. Kubicki ◽  
I. Weyna ◽  
I. Janić
Keyword(s):  
Temperature Dependence ◽  
Cellulose Acetate ◽  
Fluorescence Anisotropy ◽  
Thermal Relaxation ◽  
Effect Of Temperature ◽  
Torsional Vibrations ◽  
Slow Increase ◽  
Cellulose Acetate Film ◽  
Luminescent Centre

The effect of temperature (103 K < T < 303 K) upon the limiting fluorescence anisotropy r0 of POPOP was investigated in a cellulose acetate film. A slow increase in r0 was observed when reducing the temperature. Based on the Jabłoński theory, the frequency of the torsional vibrations of POPOP was determined to be w = 1.3 x 1012s−1. The depolarization due to these torsional vibrations was found to occur immediately following excitation during the thermal relaxation of the luminescent centre, thus somewhat lowering the value of the fundamental fluorescence anisotropy rf to the limiting r0 value.

scholarly journals Effect of Temperature on Reliability and Degradation of 0.63?m Laser Diode

2012 ◽  
Vol 9 (1) ◽  
pp. 141-147
Author(s):  
Baghdad Science Journal
Keyword(s):  
Temperature Dependence ◽  
Laser Diode ◽  
System Application ◽  
Effect Of Temperature ◽  
Reliability Test ◽  
Test Results ◽  
Degradation Behaviour ◽  
Light Power ◽  
Aging Test ◽  
Power Operation

The reliability of optical sources is strongly dependent on the degradation and device characteristics are critically dependent on temperature. The degradation behaviours and reliability test results for the laser diode device (Sony-DL3148-025) will be presented .These devices are usually highly reliable. The degradation behaviour was exhibited in several aging tests, and device lifetimes were then estimated. The temperature dependence of 0.63?m lasers was studied. An aging test with constant light power operation of 5mW was carried out at 10, 25, 50 and 70°C for 100hours. Lifetimes of the optical sources have greatly improved, and these optical sources can be applied to various types of transmission systems. Within this degradation range, the device life for system application is estimated to be more than 100 h at 70 ºC at a constant power of 5mW.

TEMPERATURE DEPENDENCE OF ELECTRICAL RESISTANCE OF INDIVIDUAL CARBON NANOTUBES AND CARBON NANOTUBES NETWORK

2012 ◽  
Vol 26 (21) ◽  
pp. 1250136 ◽  
Author(s):  
SAJJAD DEHGHANI ◽  
MOHAMMAD KAZEM MORAVVEJ-FARSHI ◽  
MOHAMMAD HOSSEIN SHEIKHI
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Dependence ◽  
Electric Fields ◽  
Electrical Resistance ◽  
Electrode Materials ◽  
Effect Of Temperature ◽  
Electrode Spacing ◽  
Single Wall Carbon Nanotubes ◽  
Tube Metal

We present a model to understand the effect of temperature on the electrical resistance of individual semiconducting single wall carbon nanotubes (s-SWCNTs) of various diameters under various electric fields. The temperature dependence of the resistance of s-SWCNTs and metallic SWCNTs (m-SWCNTs) are compared. These results help us to understand the temperature dependence of the resistance of SWCNTs network. We experimentally examine the temperature dependence of the resistance of random networks of SWCNTs, prepared by dispersing CNTs in ethanol and drop-casting the solution on prefabricated metallic electrodes. Examining various samples with different electrode materials and spacings, we find that the dominant resistance in determination of the temperature dependence of resistance of the network is the resistance of individual tubes, rather than the tube–tube resistance or tube–metal contact resistance. It is also found that the tube–tube resistance depends on the electrode spacing and it is more important for larger electrode spacings. By applying high electric field to burn the all-metallic paths of the SWCNTs network, the temperature dependence of the resistance of s-SWCNTs is also examined. We also investigate the effect of acid treatment of CNTs on the temperature dependence of the resistance of SWCNTs and also multi-wall CNTs (MWCNTs) networks.

Temperature Dependence and Martensitic Transformation of Ti50Pt50 Shape Memory Alloys

2014 ◽  
Vol 1019 ◽  
pp. 379-384
Author(s):  
M.P. Mashamaite ◽  
Hasani Rich Chauke ◽  
Rosinah Mahlangu ◽  
P.E. Ngoepe
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Displacive Transformation ◽  
B2 Phase ◽  
Recent Experimental Work

Shape memory alloys (SMAs) are a fascinating group of metals that have two remarkable properties, the shape memory effect and superelasticity. The TiPt structure with the B2 phase has been reported to undergo a reversible displacive transformation to B19 martensite at about 1200K. However, this system could serve in principle as the basis of high-temperature shape memory alloys. Molecular dynamics study of martensitic transformation in platinum titanium alloys was performed to investigate the effect of temperature dependence on B2 and B19 structures at 50 at.%Pt. The NPT ensemble was used to determine the properties of these systems and we found good comparisons with recent experimental work. The temperature dependence of TiPt shows potential martensitic change when B19 is heated to extreme high temperatures of 273K up to 1573K.

Effect of Temperature Dependence of Magnetic Properties on Heating Characteristics of Induction Heater

2010 ◽  
Vol 46 (8) ◽  
pp. 3018-3021 ◽  
Author(s):  
Hiroyuki Kagimoto ◽  
Daisuke Miyagi ◽  
Norio Takahashi ◽  
Naoki Uchida ◽  
Keiji Kawanaka
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Induction Heater

Temperature Effect on Phase-Transition Radiation of Water

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
M. Q. Brewster ◽  
K.-T. Wang ◽  
W.-H. Wu ◽  
M. G. Khan
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Temperature Dependence ◽  
Transition Probability ◽  
Cloud Droplet ◽  
Radiation Absorption ◽  
Effect Of Temperature ◽  
Strong Temperature Dependence ◽  
Atmospheric Windows ◽  
Radiative Phase

Infrared radiation associated with vapor-liquid phase transition of water is investigated using a suspension of cloud droplets and mid-infrared (IR) (3–5 μm) radiation absorption measurements. Recent measurements and Monte Carlo (MC) modeling performed at 60 °C and 1 atm resulted in an interfacial radiative phase-transition probability of 5 × 10−8 and a corresponding surface absorption efficiency of 3–4%, depending on wavelength. In this paper, the measurements and modeling have been extended to 75 °C in order to examine the effect of temperature on water's liquid-vapor phase-change radiation. It was found that the temperature dependence of the previously proposed phase-change absorption theoretical framework by itself was insufficient to account for observed changes in radiation absorption without a change in cloud droplet number density. Therefore, the results suggest a strong temperature dependence of cloud condensation nuclei (CCN) concentration, i.e., CCN increasing approximately a factor of two from 60 °C to 75 °C at near saturation conditions. The new radiative phase-transition probability is decreased slightly to 3 × 10−8. Theoretical results were also calculated at 50 °C in an effort to understand behavior at conditions closer to atmospheric. The results suggest that accounting for multiple interface interactions within a single droplet at wavelengths in atmospheric windows (where anomalous IR radiation is often reported) will be important. Modeling also suggests that phase-change radiation will be most important at wavelengths of low volumetric absorption, i.e., atmospheric windows such as 3–5 μm and 8–10 μm, and for water droplets smaller than stable cloud droplet sizes (<20 μm diameter), where surface effects become relatively more important. This could include unactivated, hygroscopic aerosol particles (not CCN) that have absorbed water and are undergoing dynamic evaporation and condensation. This mechanism may be partly responsible for water vapor's IR continuum absorption in these atmospheric windows.

THE TEMPERATURE DEPENDENCE OF APPARENT DIELECTRIC CONSTANTS OF ADSORBATES ON NON-POROUS TITANIUM DIOXIDE

1957 ◽  
Vol 35 (12) ◽  
pp. 1534-1541 ◽  
Author(s):  
S. E. Petrie ◽  
R. McIntosh ◽  
E. W. Channen
Keyword(s):  
Dielectric Constant ◽  
Titanium Dioxide ◽  
Temperature Dependence ◽  
Experimental Error ◽  
Adsorption Process ◽  
Porous Titanium ◽  
Dielectric Constants ◽  
Effect Of Temperature ◽  
Apparent Dielectric Constant

The temperature dependence of the apparent dielectric constants of various adsorbed polar gases on finely divided, non-porous titanium dioxide has been determined. Within the experimental error, the apparent dielectric constant of the material adsorbed in the monolayer is independent of temperature. The effect of temperature on the dielectric constant for gas adsorbed beyond the monolayer depends on the adsorbate. These results have been interpreted as indicating that molecules initially adsorbed are oscillators, while those adsorbed in later stages of the adsorption process may be rotators or oscillators.

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