A Time-Dependent Numerical Model for Spherically Symmetric Hailstone Growth Thermodynamics under Constant Ambient Conditions

1980 ◽  
Vol 37 (8) ◽  
pp. 1808-1820 ◽  
Author(s):  
E. P. Lozowski ◽  
R. D'Amours
Keyword(s):  
Numerical Model ◽  
Time Dependent ◽  
Spherically Symmetric ◽  
Ambient Conditions

scholarly journals Dynamic Pulse Buckling of Composite Stanchions in the Sub-Cargo Floor Area of a Civil Regional Aircraft

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3594
Author(s):  
Andrea Sellitto ◽  
Francesco Di Caprio ◽  
Michele Guida ◽  
Salvatore Saputo ◽  
Aniello Riccio
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Low Frequency ◽  
Time Dependent ◽  
Structural Behavior ◽  
Cyclic Loads ◽  
Civil Aircraft ◽  
Compressive Loads ◽  
Pulse Buckling ◽  
Implicit And Explicit

This work is focused on the investigation of the structural behavior of a composite floor beam, located in the cargo zone of a civil aircraft, subjected to cyclical low-frequency compressive loads with different amplitudes. In the first stage, the numerical models able to correctly simulate the investigated phenomenon have been defined. Different analyses have been performed, aimed to an exhaustive evaluation of the structural behavior of the test article. In particular, implicit and explicit analyses have been considered to preliminary assess the capabilities of the numerical model. Then, explicit non-linear analyses under time-dependent loads have been considered, to predict the behavior of the composite structure under cyclic loading conditions. According to the present investigation, low-frequency cyclic loads with peak values lower than the static buckling load value are not capable of triggering significant instability.

scholarly journals Temperature Analysis of Obstacle Lighting Lamp Working under Various Ambient Conditions: Theoretical and Practical Experiments

2019 ◽  
Vol 9 (22) ◽  
pp. 4951
Author(s):  
Wotzka ◽  
Błachowicz ◽  
Weisser
Keyword(s):  
Numerical Model ◽  
Power Supply System ◽  
Heat Emission ◽  
Operating Conditions ◽  
Physical Models ◽  
Heat Sources ◽  
Ambient Conditions ◽  
Airflow Velocity ◽  
Light Emitting ◽  
Theoretical Analyses

The article presents the results of experimental and theoretical works aimed at determining the distribution of heat emitted by an obstacle lighting lamp. These kind of lamps are commonly applied as a warning for air traffic vehicles. There is a need for lighting devices with various intensities, whose application depends on the location and operating conditions. The overall aim of the author’s work is to develop a computer model that would enable us to conduct research aimed at determining the optimal parameters of lamp operation without the need to build many physical models. Measurements of heat emitted by a currently manufactured lamp were made, and based on these, a numerical model of the lamp operating under laboratory conditions was developed. The considered lamp has two heat sources, one of which is light-emitting diodes (LEDs), while the other heat source consists of stabilizers and other elements of the lamp power supply system. After positive experimental verification of the numerical model, theoretical analyses of heat emission under various meteorological conditions were carried out, while the values of ambient temperature and airflow velocity were changed; then, the influence of these parameters on the temperature distribution on the surface of the lamp was determined.

On the Cherenkov radiation from extended charge distributions

2000 ◽  
Vol 77 (10) ◽  
pp. 775-784 ◽  
Author(s):  
M Villavicencio ◽  
J L Jiménez ◽  
JAE Roa-Neri
Keyword(s):  
Explicit Expression ◽  
Charge Distribution ◽  
Constant Velocity ◽  
Cherenkov Radiation ◽  
Poynting Vector ◽  
Time Dependent ◽  
Spherically Symmetric ◽  
Charge Distributions ◽  
Extended Charge ◽  
A Charge

In this work the Cherenkov effect for extended charge distributions is analyzed using two different methods. In the first method, the Poynting vector is employed to determine the energy radiated, whereas in the second one, we apply the idea of generating time-dependent elemental dipoles, induced by a charge distribution moving with constant velocity, inside a material medium. An explicit expression for the Cherenkov radiation generated by some different kinds of spherically symmetric charge, travelling inside a medium, is obtained.PACS Nos.: 03.50.De, 41.20.Bt, 41.60.-m, 41.60.Bq

Time-dependent vibrational spectral analysis of first principles trajectory of methylamine with wavelet transform

2017 ◽  
Vol 19 (15) ◽  
pp. 9912-9922 ◽  
Author(s):  
Sohag Biswas ◽  
Bhabani S. Mallik
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Spectral Analysis ◽  
First Principles ◽  
Density Functional ◽  
Time Dependent ◽  
Amine Group ◽  
Ambient Conditions ◽  
Functional Theory ◽  
Fluctuation Dynamics

The fluctuation dynamics of amine stretching frequencies, hydrogen bonds, dangling N–D bonds, and the orientation profile of the amine group of methylamine (MA) were investigated under ambient conditions by means of dispersion-corrected density functional theory-based first principles molecular dynamics (FPMD) simulations.

Self-Interstitial Injection Effects on Carbon Diffusion in Silicon At High Temperatures

1985 ◽  
Vol 59 ◽  
Author(s):  
L. A. Ladd ◽  
J. P. Kalejs
Keyword(s):  
High Temperatures ◽  
Carbon Diffusion ◽  
Time Dependent ◽  
Ambient Conditions ◽  
Significant Time ◽  
Temperature Range ◽  
Carbon Diffusivity ◽  
Sims Analysis ◽  
Diffusion Profiles

ABSTRACTCarbon diffusivity is reported for different ambient conditions imposed during annealing of silicon in the temperature range from 800 to 100°C, which produce varying levels of silicon self-interstitial supersaturation. The diffusivities are deduced from SIMS analysis of carbon out-diffusion profiles. Carbon diffusivity is increased by up to a factor of 70 in annealing with phosphorus in-diffusion, and by a factor of as much as seven in an oxidizing ambient, when compared to anneals in a nitrogen ambient. The enhancements tend to decrease above 11000C. This behavior can be explained by attributing the increase in carbon diffusivity to self-interstitial supersaturation which increases the concentration of highly mobile carbon selfinterstitial pairs. Significant time dependent effects were also observed for 800 and 9000C phosphorus in-diffusion conditions.

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