Theoretical model for predicting thermoelectric properties of tin chalcogenides

2020 ◽  
Vol 22 (34) ◽  
pp. 18989-19008 ◽  
Author(s):  
Raveena Gupta ◽  
Naveen Kumar ◽  
Prabhjot Kaur ◽  
Chandan Bera
Keyword(s):  
Theoretical Model ◽  
Thermoelectric Properties ◽  
Theoretical Modelling ◽  
Tin Chalcogenides

Accelerated prediction of thermoelectric properties by a simple theoretical modelling.

scholarly journals THEORETICAL MODELLING OF THE COLLABORATION BETWEEN CONSUMERS AND PROVIDERS OF EDUCATIONAL SERVICES IN THE IMPLEMENTATION OF SCHOOL’S MISSION

2018 ◽  
Vol 1 (8) ◽  
pp. 24
Author(s):  
Aušrinė Gumuliauskienė ◽  
Jovita Starkutė
Keyword(s):  
Theoretical Model ◽  
Value Creation ◽  
Meta Analysis ◽  
Essential Elements ◽  
Theoretical Modelling ◽  
Theoretical Interpretation ◽  
Educational Services ◽  
School Services ◽  
Collaboration Process

<em>The article deals with the problem of the collaboration between consumers and providers of educational services in the implementation of school’s mission. The concept of the consumers and providers of school services has been presented, the mission of the school of today has been defined, the contradictions of its implementation in the postmodern society have been highlighted, the importance of the collaboration between parents as consumers of educational services and pedagogues as providers of educational services in the implementation of school’s mission has been substantiated, the factors conditioning collaboration, the principles determining the involvement and participation of the consumers of educational services, and the essential elements of collaboration have been actualized. A theoretical interpretation of the concept of value creation in interaction has been presented. Referring to the analysis and meta-analysis of the development and structure of the collaboration process at school a theoretical model of the development of collaboration between consumers and providers of educational services at school has been conceptualized</em>

Theoretical modelling of the self-tapping screw fastening process

2001 ◽  
Vol 215 (2) ◽  
pp. 135-154 ◽  
Author(s):  
L D Seneviratne ◽  
F A Ngemoh ◽  
S W E Earles ◽  
K A Althoefer
Keyword(s):  
Theoretical Model ◽  
Control Strategies ◽  
The Self ◽  
Theoretical Modelling ◽  
Insertion Torque ◽  
Monitoring And Control ◽  
Screw Insertion ◽  
Engineering Mechanics ◽  
And Control ◽  
Insertion Process

The results of a theoretical study of the self-tapping screw insertion process are presented. Fundamental concepts of engineering mechanics are employed to analyse the axial torque required to complete a general self-tapping screw insertion operation. Equations for the screw insertion torque as a function of screw, hole and material properties are presented. Experimental results for torque signature signals are compared with the predictions of the theoretical model, confirming the validity of the model. The theoretical model provides a basis for developing automated monitoring and control strategies for self-tapping screw fastenings.

Modelling of a Magnetorheological Fluid Knee in a Prosthetic Leg

2016 ◽  
Author(s):  
The Nguyen ◽  
Saurabh Bapat ◽  
Xinli Wang
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Theoretical Model ◽  
Theoretical Data ◽  
Magnetorheological Fluid ◽  
Theoretical Modelling ◽  
Gap Size ◽  
Applied Current ◽  
Prosthetic Knee ◽  
Braking Torque

The purpose of the study is to theoretically model a prosthetic knee. A knee similar to magnetorheological fluid (MRF) brake is designed and the study focuses on modelling the MRF knee, predict the torque and compare it with the experimental data. The torque generated by the MRF knee is highly dependent on the gap size, angle, and the applied current. Here, the MRF knee features a non-circular rotor which results in a variable gap size for the MR fluid, between the stator and the rotor. Therefore, the gap size varies with the angle of the knee. When the current is applied and MR knee is subjected to a magnetic field, the yield stress produces the shear friction due to which the braking torque is generated. This derives the braking torque as a function of angle and applied current. A torque equation is derived from the theoretical data to yield the predicted results. In addition to the theoretical modelling and derived torque equations, the torque for the MRF fluid is also calculated experimentally. For the validation of the theoretical model and the derived torque equations, they were compared with the experimental results.

Theoretical Investigations Of Interfacial Scattering Effects On Thermoelectric Properties Of Bulk Nanostructured PbTe System

MRS Advances ◽  
2018 ◽  
Vol 3 (24) ◽  
pp. 1329-1334 ◽  
Author(s):  
Neeleshwar Sonnathi ◽  
Anjali Panwar ◽  
Vikas Malik ◽  
Anjana Bagga
Keyword(s):  
Thermoelectric Properties ◽  
Power Factor ◽  
Room Temperature ◽  
Bulk Material ◽  
Theoretical Modelling ◽  
Boltzmann Transport ◽  
Energy Filtering ◽  
Electronic Parameters ◽  
Spark Plasma ◽  
Interfacial Scattering

ABSTRACTEnhancement of thermoelectric properties at room temperature has been recently demonstrated by spark plasma sintered PbTe nanocubes as compared to other PbTe nanostructures as well as Bulk material. The Seebeck coefficient has been reported to be 400 µV/K which is much higher than the bulk. Moreover, a moderate electrical conductivity ∼ 8000 S/m at room temperature results in considerable higher value of power factor S2σ ∼ 1.28 x 10-3 Wm-1K-2. The enhanced thermoelectric properties have been conjectured to be present due to energy filtering effects at numerous interfaces introduced by nanostructuring. We study how the interfacial scattering affects the power factor by performing theoretical modelling based on Boltzmann Transport Equation (BTE). We also investigate in detail, the role of various electronic parameters such as size, shape, mobility and effective mass etc., on interfacial scattering to optimize its effect on power factor.

scholarly journals Underplatform Dampers for Turbine Blades: Theoretical Modelling, Analysis and Comparison With Experimental Data

1999 ◽  
Author(s):  
Kenan Y. Sanliturk ◽  
David J. Ewins ◽  
Anthony B. Stanbridge
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Normal Load ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Hysteresis Loops ◽  
Theoretical Modelling ◽  
Contact Behaviour ◽  
Modes Of Vibration ◽  
Opening And Closing

This paper describes a theoretical model for analysing the dynamic characteristics of wedge-shaped underplatform dampers for turbine blades, with the objective that this model can be used to minimise the need for conducting expensive experiments for optimising such dampers. The theoretical model presented in the paper has several distinct features to achieve this objective including: (i) it makes use of experimentally-measured contact characteristics (hysteresis loops) for description of the basic contact behaviour of a given material combination with representative surface finish, (ii) the damper motion between the blade platform locations is determined according to the motion of the platforms, (iii) three-dimensional damper motion is included in the model, and (iv) normal load variation across the contact surfaces during vibration is included, thereby accommodating contact opening and closing during vibration. A dedicated non-linear vibration analysis program has been developed for this study and predictions have been verified against experimental data obtained from two test rigs. Two cantilever beams were used to simulate turbine blades with real underplatform dampers in the first experiment. The second experiment comprised real turbine blades with real underplatform damper. Correlation of the predictions and the experimental results revealed that the analysis can predict (i) the optimum damping condition, (ii) the amount of response reduction and (iii) the natural frequency shift caused by friction dampers, all with acceptable accuracy. It has also been shown that the most commonly-used underplatform dampers in practice are prone to rolling motion, an effect which reduces the damping in certain modes of vibration usually described as the lower nodal diameter bladed-disc modes.

Emotions in strategic leadership: A Literature review and theoretical modelling for future research directions

2017 ◽  
Vol 20 (03) ◽  
pp. 311-340
Author(s):  
Alicia Ohlsson ◽  
Gerry Larsson
Keyword(s):  
Theoretical Model ◽  
Literature Review ◽  
Theoretical Modelling ◽  
Strategic Leadership ◽  
Future Research ◽  
Research Directions ◽  
Organizational Framing ◽  
Grounded Theory Method ◽  
Starting Point ◽  
Future Research Directions

AbstractThe aim was to explore the existing literature on emotion and strategic leadership in a systematic review and to synthesize it into a theoretical model. A literature review on emotion in connection to strategic leadership was undertaken. After adhering to the search strategy and exclusion criteria, 46 peer-reviewed texts consisting of articles and relevant book chapters remained. The texts were analyzed according to the grounded theory method (GTM) to generate a new theoretical model and a core variable was identified, organizational emotion shaping. The model attempts to show how the interaction of individual and organizational framing factors with the strategic leader's tasks and challenges lead to emotion shaping internal and external of the organization. Suggestions for future research were formed and suggestions of practical implications were given. This literature review and theoretical integration offers a starting point for potential areas of further exploration.

scholarly journals Lateral resistance of “rigid” pipelines and cables on rocky seabeds

2019 ◽  
Vol 56 (6) ◽  
pp. 823-839
Author(s):  
Terry Griffiths ◽  
David J. White ◽  
Scott Draper ◽  
Adam Leighton ◽  
Liang Cheng ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Theoretical Modelling ◽  
Pipe Diameter ◽  
Physical Experiments ◽  
Lateral Resistance ◽  
Current Design ◽  
Subsea Pipelines ◽  
Rock Size ◽  
Effective Friction

Accurate assessment of lateral resistance is critical to ensure the on-bottom stability and integrity of subsea pipelines and cables in the oil–gas and marine renewable energy industries. However, on rocky seabeds recommended practices provide limited recommendations on pipe–seabed interaction, suggesting only a single value for the friction coefficient of 0.6. This paper reports on a programme of physical experiments and theoretical modelling investigating the lateral resistance of pipes on rocky seabeds. It is shown that the peak and mean effective friction can significantly exceed the interface (or Coulomb) friction coefficient when the pipe diameter (D) is similar to the median rock diameter (dn50). Only when the pipe diameter becomes large compared to the rock size does the mean effective friction approach the interface friction. The effective friction coefficient was found to vary with variability in rock size and shape, as well as the length of pipe relative to median rock diameter. Each of these findings is reproduced well using the theoretical model. Collectively, the results demonstrate that the effective lateral friction coefficient may be higher than 0.6 for mean friction, and significantly higher for peak friction. This implies that inaccuracy may exist in current design, which may be rectified using the theoretical model.

scholarly journals Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1010
Author(s):  
Jie Ren ◽  
Jianlin Zhong ◽  
Lin Yao ◽  
Zhongwei Guan
Keyword(s):  
High Pressure ◽  
Theoretical Model ◽  
Rapid Change ◽  
Compressibility Factor ◽  
Ideal Gas ◽  
Theoretical Modelling ◽  
The Relationship ◽  
Metal Wall ◽  
Ideal Gas Model ◽  
The Ideal

A high-pressure pneumatic catapult works under extreme boundaries such as high-pressure and rapid change of pressure and temperature, with the features of nonlinearity and gas-solid convection. In the thermodynamics processes, the pressure is much larger than the critical pressure, and the compressibility factor can deviate from the Zeno line significantly. Therefore, the pneumatic performance and thermo-physical properties need to be described with the real gas hypothesis instead of the ideal gas one. It is found that the analytical results based on the ideal gas model overestimate the performance of the catapult, in comparison to the test data. To obtain a theoretical model with dynamic leakage compensation, leakage tests are carried out, and the relationship among the leakage rate, pressure and stroke is fitted. The compressibility factor library of the equation of state for compressed air is established and evaluated by referring it to the Nelson-Obert generalized compressibility charts. Based on the Peng–Robinson equation, a theoretical model of the high-pressure pneumatic catapult is developed, in which the effects of dynamic leakage and the forced convective heat transfer between the gas and the metal wall are taken into account. The results from the theoretical model are consistent with the data from ejection tests. This research presents an approach to study the performance of a high-pressure pneumatic catapult with high precision.

scholarly journals Theoretical model of geothermal tail water reinjection based on an equivalent flow channel model: A case study in Xianxian, North China Plain

2019 ◽  
Vol 37 (2) ◽  
pp. 849-864 ◽  
Author(s):  
Liu Yanguang ◽  
Liu Guihong ◽  
Zhao Zhihong ◽  
Zhang Hongliang
Keyword(s):  
Theoretical Model ◽  
Channel Model ◽  
Back Analysis ◽  
Tracer Tests ◽  
Flow Channel ◽  
Theoretical Modelling ◽  
Tracer Transport ◽  
Production Well ◽  
Geothermal Well ◽  
Thermal Breakthrough

Based on tracer tests and the equivalent flow channel model, this study proposes a theoretical modelling framework to back-calculate the unknown parameters of geothermal reservoirs and predict the thermal breakthrough in production wells. The inverse modelling module combines the analytical solution of the tracer transport equation with the method of moving asymptotes, and then an analytical model that considers heat advection and transfer was used to predict the thermal breakthrough in a production well. Based on the results of tracer tests in the double geothermal wells, Xianxian geothermal field, China, two equivalent flow channels were determined, and their average flow velocity, dispersion coefficient, section area, and channel length were estimated using this theoretical framework. The possible thermal breakthrough in the production well and its main influencing factors are also discussed. The theoretical model was applied to the engineering case, and the tracer test data were used to carry out the parameter back analysis and obtain the goodness of fit ( R2)=0.7907 > 0.6, indicating that the optimization result strongly correlated with the measured value and the fit was good. The values of the thermal reservoir parameters from the tracer test’s back analysis were used to predict the thermal breakthrough for the geothermal well system. The results indicated that due to the lower tracer recovery rate, the hydraulic connection between the production well and the recharge well was poor. During the 100-year service life of a geothermal well system, the production water temperature will not obviously change, and no thermal breakthrough will occur.

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