Rigidity Analysis and Optimization of Warren Beams in Torsion

1977 ◽  
Vol 99 (1) ◽  
pp. 269-273
Author(s):  
R. C. Bahi ◽  
S. Chandra ◽  
P. C. Pandey
Keyword(s):  
Theoretical Model ◽  
Experimental Investigations ◽  
Rigidity Analysis ◽  
Static Performance ◽  
Weight Criterion ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement

This paper reports analytical and experimental investigations on the static performance of warren beams in torsion. The theoretical results have been found to be in good agreement with the experimental values. The proposed theoretical model has further been used to obtain optimized proportions for the warren beams in terms of stiffness/weight criterion.

Thermocouple Response Characteristics in Deflagrating Low-Conductivity Materials

1971 ◽  
Vol 93 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Nam P. Suh ◽  
C. L. Tsai
Keyword(s):  
Theoretical Model ◽  
Gas Phase ◽  
Wire Diameter ◽  
Solid Propellants ◽  
Optimum Ratio ◽  
Response Characteristics ◽  
Bead Diameter ◽  
Double Base ◽  
Theoretical Results ◽  
Good Agreement

The transient thermocouple response characteristics in deflagrating low-conductivity materials with high temperature gradients were investigated theoretically and experimentally. The theoretical model considers the thermocouple bead and lead wires separately, and the two resulting partial differential equations are solved simultaneously by a finite difference technique. The experimental results are obtained by embedding various size thermocouple wires in double-base solid propellants and consequently measuring the temperature profiles and the surface temperatures. The theoretical model is used to predict the experimentally measured temperatures. There is good agreement. The experimentally measured values are smaller than the correct surface temperature, corresponding to the model prediction for zero wire diameter, by at least 20 percent even when 1/2-mil thermocouple wire is used. Both the experimental and theoretical results show a plateau when the thermocouple bead emerges from the solid into the gas phase. The theoretical results also show that there is an optimum ratio of. the thermocouple bead diameter to the wire diameter, which is found to be close to three

scholarly journals Current Status and Developments of the Atomic Database on Rare-Earths at Mons University (DREAM)

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 18 ◽  
Author(s):  
Pascal Quinet ◽  
Patrick Palmeri
Keyword(s):  
Rare Earths ◽  
Spectral Lines ◽  
Oscillator Strengths ◽  
Current Status ◽  
Time Resolved ◽  
Hartree Fock ◽  
Lanthanide Atoms ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement

The main purpose of the Database on Rare Earths At Mons University (DREAM) is to provide the scientific community with updated spectroscopic parameters related to lanthanide atoms (Z = 57–71) in their lowest ionization stages. The radiative parameters (oscillator strengths and transitions probabilities) listed in the database have been obtained over the past 20 years by the Atomic Physics and Astrophysics group of Mons University, Belgium, thanks to a systematic and extensive use of the pseudo-relativistic Hartree-Fock (HFR) method modified for taking core-polarization and core-penetration effects into account. Most of these theoretical results have been validated by the good agreement obtained when comparing computed radiative lifetimes and accurate experimental values measured by the time-resolved laser-induced fluorescence technique. In the present paper, we report on the current status and developments of the database that gathers radiative parameters for more than 72,000 spectral lines in neutral, singly-, doubly-, and triply-ionized lanthanides.

Influence of the Contact Pressure on the Rolling Resistance Moments in Dry Ball-Race Contacts

2014 ◽  
Vol 658 ◽  
pp. 305-310
Author(s):  
Alina Corina Dumitrascu ◽  
Gelu Ianus ◽  
Dumitru Olaru
Keyword(s):  
Theoretical Model ◽  
Contact Pressure ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Rolling Resistance ◽  
Theoretical Models ◽  
Hertzian Contact ◽  
Experimental Methodology ◽  
Experimental Values ◽  
Good Agreement

Based on a theoretical model and an experimental methodology for defining the rolling resistance moments in a modified thrust ball bearing having only 3 balls, the authors experimentally investigated the influence of the Hertzian contact pressure on rolling resistance moments between a ball and a race. The experiments were realized with balls having diameters between 1.588 mm and 4.762 mm with maximum Hertzian pressure between 0.2GPa and 1GPa, operating for rotational speed between 60rpm to 210 rpm. The experiments evidenced that the measured values of the rolling resistance moments have higher values that the theoretical hysteresis and curvature rolling resistance moments for low contact pressure. By increasing of the contact pressure to 1GPa the experimental values for rolling resistance moments are in good agreement with the theoretical models.

The Characteristic Analysis of a Piezoelectric Actuator for Valveless Micropumps

2006 ◽  
Vol 326-328 ◽  
pp. 1511-1514
Author(s):  
Sung Hyuk Lee ◽  
Seok Heo ◽  
Cheol Woong Kim ◽  
Kwang Joon Yoon
Keyword(s):  
Theoretical Model ◽  
Piezoelectric Actuator ◽  
Bonding Layer ◽  
Finite Element Analyses ◽  
Characteristic Analysis ◽  
Design And Optimization ◽  
Simulation Based ◽  
Piezoelectric Disk ◽  
Theoretical Results ◽  
Good Agreement

The behavior of a circular piezoelectric actuator for volumetric micropump has been investigated by using theoretical and finite element analyses. A modified theoretical model was developed to predict the behavior of a piezoelectric actuator induced by the applied voltage. The theoretical results for the diaphragm deflection were in good agreement with the results from numerical simulation. Based on the theoretical analysis, the effects of several important parameters on actuation performance have been investigated. These parameters include the dimensions and mechanical properties of the piezoelectric disk, bonding layer and elastic diaphragm materials. Consequently, it is thought that above theoretical model might be employed as a tool for design and optimization of the piezoelectric actuator for micropump application.

Lattice Dynamical Properties of Potassium

1981 ◽  
Vol 36 (11) ◽  
pp. 1242-1245
Author(s):  
O. P. Gupta
Keyword(s):  
Equilibrium Condition ◽  
Short Range ◽  
Phonon Dispersion ◽  
Waller Factor ◽  
Crystal Stability ◽  
Debye Waller Factor ◽  
Dynamical Properties ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement

The phonon dispersion, temperature dependence of the Debye temperature, Debye-Waller factor, and Grüneisen parameter of potassium are calculated using a realistic lattice dynamical model. The model considers short range pairwise forces effective upto second neighbors and an improved electron ion interaction on the lines of Bhatia. An equilibrium condition, which preserves the crystal stability, is obtained. The theoretical results are found to be in good agreement with the experimental values.

Soret Measurement for Multi-Component Hydrocarbon Mixtures from Space Experiment Conducted Onboard FOTON M3 Unmanned Satellite

2012 ◽  
Vol 225 ◽  
pp. 470-474 ◽  
Author(s):  
M. Ziad Saghir ◽  
Seshasai Srinivasan ◽  
Stefan Van Vaerenbergh
Keyword(s):  
Experimental Investigation ◽  
Space Experiment ◽  
Experimental Investigations ◽  
Hydrocarbon Mixture ◽  
Hydrocarbon Mixtures ◽  
Component System ◽  
Thermodiffusion Coefficient ◽  
Free Environment ◽  
Theoretical Results ◽  
Good Agreement

In an unprecedented experimental investigation, a binary, a ternary and a four-component hydrocarbon mixture at different pressure have been studied in a nearly convection free environment to understand the thermodiffusion process. Experimental investigations of the mixtures have been conducted in space onboard the spacecraft FOTON-M3. The experiment objective was to measure the thermodiffusion coefficient for multi-component hydrocarbon mixtures. Then the experimental results have also been used to test a thermodiffusion model that has been calibrated based on the results of previous experimental investigations. Results showed a good agreement with current theoretical results except for the four-component system where discrepancies were found and discussed.

Rotating Wakes in Vaneless Diffusers

1960 ◽  
Vol 82 (3) ◽  
pp. 563-570 ◽  
Author(s):  
Robert C. Dean ◽  
Yasutoshi Senoo
Keyword(s):  
Centrifugal Compressor ◽  
Simplified Model ◽  
Experimental Investigations ◽  
Pump Impeller ◽  
Vaneless Diffusers ◽  
Theoretical Results ◽  
Axially Asymmetric ◽  
Reversible Work ◽  
Good Agreement

Experimental investigations have shown that the flow discharged from a centrifugal compressor or pump impeller into a diffuser is often unsteady and axially asymmetric. A theory based upon a simplified model is developed for this type of flow. The theory predicts a significant reversible work transfer between parts of the flow with different velocities. This effect only occurs in cases of rotating distortion patterns; stationary distortion patterns, therefore, behave differently. Theoretical results are compared to measurements and good agreement is found. The implications of the theory have been investigated by means of machine computations and are discussed herein.

Self-Compression and Diamond Nucleation In Irradiated Carbon Onions - A Theoretical Model

1998 ◽  
Vol 540 ◽  
Author(s):  
M. Zaiser
Keyword(s):  
Theoretical Model ◽  
Diamond Formation ◽  
Diamond Nucleation ◽  
Diamond Crystals ◽  
Carbon Onions ◽  
Experimental Findings ◽  
Theoretical Results ◽  
Good Agreement

AbstractThe nucleation of small diamond crystals during irradiation of spherical graphitic particles (’bucky onions’) is discussed. A mechanism for irradiation-induced self-compression of such ’onions’ is proposed. It is demonstrated that this may yield pressures which are sufficiently high for diamond formation. The theoretical results are in good agreement with experimental findings.

scholarly journals Transition spectral parameters of In-like Ba, La and Ce ions

2021 ◽  
Author(s):  
Miao Wu ◽  
Zhencen He
Keyword(s):  
Quantum Electrodynamics ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Oscillator Strengths ◽  
Spectral Parameters ◽  
Hartree Fock ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement ◽  
Line Strengths

The spectral parameters (energy levels, wavelengths, transition probabilities, line strengths and oscillator strengths) of resonance lines for Ba VIII, La IX and Ce X have been performed using the multiconfiguration Dirac-Hartree-Fock method, the contributions of quantum electrodynamics and Breit interactions correction are taken into considered. The calculated results of energy levels and wavelengths are in good agreement with experimental values and other calculation. The number of energy levels and wavelengths considered is larger than that of any other experiment values and other calculations. The transition probabilities, line strengths and oscillator strengths are also calculated where no other theoretical results and experimental values are available.

Investigation of some radiation interaction parameters for bacteria isolated from the soil in the low energy region

2020 ◽  
Vol 98 (3) ◽  
pp. 251-259
Author(s):  
F. Akman ◽  
B. Enez ◽  
S. Agüloğlu Fincan ◽  
F. Akdemir ◽  
I.H. Geçibesler
Keyword(s):  
Bacillus Subtilis ◽  
Effective Atomic Number ◽  
Mass Attenuation Coefficient ◽  
Geobacillus Stearothermophilus ◽  
Beam Geometry ◽  
Bacillus Simplex ◽  
Experimental Values ◽  
Attenuation Characteristics ◽  
Theoretical Results ◽  
Good Agreement

The purpose of this work, investigation of radiation attenuation characteristics, such as mass attenuation coefficient (μ/ρ), molar extinction coefficient (ε), effective atomic number (Zeff), and electron density (NE), of isolated bacteria from soil samples taken from Diyarbakır in Turkey. The experiments were performed using a narrow beam geometry with the help of the a high-resolution Si(Li) detector and three different radioactive sources at 15 different photon energies. The ε, Zeff, and NE values for some bacteria isolated from soil, such as Bacillus megaterium, Bacillus simplex, Bacillus subtilis, and commercially purchased Geobacillus stearothermophilus bacterium, were obtained from the measured μ/ρ results in the energy range from 13.94 to 88.04 keV. The experimental values were checked with two different theoretical results and good agreement was observed among them. The results show that Bacillus simplex bacterium has the highest values of μ/ρ and Zeff and Bacillus subtilis bacterium has the biggest values of ε and NE among the present bacteria.

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