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.

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

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.

scholarly journals The κ-statistics approach to epidemiology

2020 ◽  
Author(s):  
Giorgio Kaniadakis ◽  
Mauro M. Baldi ◽  
Thomas S. Deisboeck ◽  
Giulia Grisolia ◽  
Dionissios T. Hristopulos ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Statistical Approach ◽  
Weibull Model ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Systematic Analysis ◽  
Epidemiological Analysis ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

Abstract A great variety of complex physical, natural and artificial systems are governed by statistical distributions, which often follow a standard exponential function in the bulk, while their tail obeys the Pareto power law. The recently introduced κ-statistics framework predicts distribution functions with this feature. A growing number of applications in different fields of investigation are beginning to prove the relevance and effectiveness of κ-statistics in fitting empirical data. In this paper, we use κ-statistics to formulate a statistical approach for epidemiological analysis. We validate the theoretical results by fitting the derived κ-Weibull distributions with data from the plague pandemic of 1417 in Florence as well as data from the COVID-19 pandemic in China over the entire cycle that concludes in April 16, 2020. As further validation of the proposed approach we present a more systematic analysis of COVID-19 data from countries such as Germany, Italy, Spain and United Kingdom, obtaining very good agreement between theoretical predictions and empirical observations. For these countries we also study the entire first cycle of the pandemic which extends until the end of July 2020. The fact that both the data of the Florence plague and those of the Covid-19 pandemic are successfully described by the same theoretical model, even though the two events are caused by different diseases and they are separated by more than 600 years, is evidence that the κ-Weibull model has universal features.

scholarly journals The κ-statistics approach to epidemiology

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Giorgio Kaniadakis ◽  
Mauro M. Baldi ◽  
Thomas S. Deisboeck ◽  
Giulia Grisolia ◽  
Dionissios T. Hristopulos ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Statistical Approach ◽  
Weibull Model ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Systematic Analysis ◽  
Epidemiological Analysis ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

AbstractA great variety of complex physical, natural and artificial systems are governed by statistical distributions, which often follow a standard exponential function in the bulk, while their tail obeys the Pareto power law. The recently introduced $$\kappa $$ κ -statistics framework predicts distribution functions with this feature. A growing number of applications in different fields of investigation are beginning to prove the relevance and effectiveness of $$\kappa $$ κ -statistics in fitting empirical data. In this paper, we use $$\kappa $$ κ -statistics to formulate a statistical approach for epidemiological analysis. We validate the theoretical results by fitting the derived $$\kappa $$ κ -Weibull distributions with data from the plague pandemic of 1417 in Florence as well as data from the COVID-19 pandemic in China over the entire cycle that concludes in April 16, 2020. As further validation of the proposed approach we present a more systematic analysis of COVID-19 data from countries such as Germany, Italy, Spain and United Kingdom, obtaining very good agreement between theoretical predictions and empirical observations. For these countries we also study the entire first cycle of the pandemic which extends until the end of July 2020. The fact that both the data of the Florence plague and those of the Covid-19 pandemic are successfully described by the same theoretical model, even though the two events are caused by different diseases and they are separated by more than 600 years, is evidence that the $$\kappa $$ κ -Weibull model has universal features.

scholarly journals Optimization of Thick Film Resistors for Low Drift

1980 ◽  
Vol 7 (1-3) ◽  
pp. 87-91 ◽  
Author(s):  
Gunnar Björklund ◽  
Lars Linde
Keyword(s):  
Theoretical Model ◽  
Thick Film ◽  
Transition Zone ◽  
Experimental Results ◽  
Film Resistor ◽  
Theoretical Predictions ◽  
Thick Film Resistor ◽  
Theoretical Results ◽  
Low Drift ◽  
Good Agreement

In order to minimize drift in a thick film resistor both printing and trimming parameters have to be optimized carefully.With the aid of a linear theoretical model it is shown how the resistance drift in the bulk transition zone and terminals of the resistor can be calculated for both trimmed and untrimmed resistors.The theoretical results are used for optimization of laser trimmed high ohmic resistors. The experimental results are in good agreement with the theoretical predictions and confirm that thick film resistors can be optimized for low drift.

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.

scholarly journals Акустические колебания алюминиевых мембран при лазерном возбуждении по термоупругому механизму

2020 ◽  
Vol 46 (10) ◽  
pp. 18
Author(s):  
А.Л. Глазов ◽  
К.Л. Муратиков
Keyword(s):  
Laser Radiation ◽  
Theoretical Model ◽  
Photoacoustic Signal ◽  
Frequency Range ◽  
Surface Absorption ◽  
Membrane Vibrations ◽  
Theoretical Results ◽  
Good Agreement

A theoretical model of the formation of a photoacoustic signal from metal membranes by laser radiation is proposed taking into account the excitation of defective states in them. The theoretical results obtained are compared for aluminum membranes with a thickness of 197 μm in the frequency range from 20 Hz to 7 kHz when they are excited by laser radiation with a wavelength of 660 nm. It is shown that the proposed theoretical model ensures good agreement between the experimental and theoretical results for membrane vibrations with a purely surface absorption of laser radiation.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

Studies of local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) crystals

2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou
Keyword(s):  
Crystal Field ◽  
Elongation Ratio ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Theoretical Results ◽  
Good Agreement

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

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