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Simulation of retention of a diamond particle in a matrix of diamond-impregnated tools

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 2016年第7期63卷 697-700页

作者： Borowiecka-Jamrozek, Joanna Lachowski, Jan Faculty of Mechatronics and Machine Designe Kielce University of Technology Tysiclecia Pañstwa Polskiego Avenue 7 Kielce25-314 Poland Faculty of Management and Computer Modelling Kielce University of Technology Tysiclecia Pañstwa Polskiego Avenue 7 Kielce25-314 Poland

The main objectives of the paper are numeric calculations of retention of diamond particle in metallic-diamond segments of circular saws. The segments are produced by means of the technology of powder metallurgy. The analysis has been preformed for cobalt, cobalt-iron and cobalt-tungsten sinters. The effective use of diamond impregnated tools is strongly depended on the retentive properties of the metal matrix, which must hold diamond grits firmly. Due to mismatch between thermal expansion coefficients of the matrix and diamond, the mechanical fields are generated in the matrix at diamond surroundings. The fields play a major role for retentive properties of matrix. It has been postulated that the potential retentive capability of a matrix can be associated with the amount of elastic and plastic deformation energy which occurs in the matrix around diamond particles.

关键词： Diamonds

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The Solution of a Two-dimensional Inverse Heat Transfer Problem Using the Trefftz Method

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Procedia Engineering 2016年 157卷 82-88页

作者： B. Maciejewska K. Strąk M. Piasecka Faculty of Management and Computer Modelling Kielce University of Technology Al. 1000-lecia P.P. 7 25-314 Kielce Poland Faculty of Mechatronics and Mechanical Engineering Kielce University of Technology Al. 1000-lecia P.P. 7 25-314 Kielce Poland

This paper deals with a two-dimensional inverse heat transfer problem solved by means of the Trefftz method. The aim of the calculations was to determine the flow boiling heat transfer coefficient from the temperature measured by infrared thermography. The experiments concerning flow boiling heat transfer were conducted for two parallel asymmetrically heated rectangular minichannels. The element heating Fluorinert (FC-72) flowing in the minichannels was a thin foil, smooth on both sides in one channel and with enhanced surface on the side in contact with the fluid in the other channel. The enhanced surface was produced with iron powder deposited by soldering. The results are presented as infrared thermographs and plots of the heat transfer coefficient against the distance from the minichannel inlet. The values of the heat transfer coefficient were calculated using the Trefftz method. In the subcooled boiling region, the values of the heat transfer coefficient were relatively low, while in the saturated boiling region, they were very high. The local values of the heat transfer coefficient reported for the surface enhanced by soldering iron powder were only slightly higher.

关键词： inverse heat transfer Trefftz method flow boiling minichannel infrared thermography

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Homotopy perturbation method combined with Trefftz method in numerical identification of liquid temperature in flow boiling

Journal of Theoretical and Applied Mechanics (Poland)

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Journal of Theoretical and Applied Mechanics (Poland) 2015年第4期53卷 969-980页

作者： Hozejowska, Sylwia Kielce University of Technology Faculty of Management and Computer Modelling Kielce Poland

The paper is focused on numerical identification of 2D temperature fields in flow boiling of the liquid through a horizontal minichannel with a rectangular cross-section. The heat transfer process in the minichannel is described by a two-dimensional energy equation with the corresponding boundary conditions. Liquid temperature is determined using the homotopy perturbation method (HPM) with Trefftz functions for Laplace'a equation. The numerical solution to the energy equation found with the HPM is compared with the solution obtained for the simplified form of the energy equation. Considering that only the thermal sublayer is taken into account, both solutions give similar results.

关键词： Inverse problems

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Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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The Lancet 2020年第10258期396卷 1204-1222页

作者： Abbafati, Cristiana Abbas, Kaja M. Abbasi, Mohammad Abbasifard, Mitra Abbasi-Kangevari, Mohsen Abbastabar, Hedayat Abd-Allah, Foad Abdelalim, Ahmed Abdollahi, Mohammad Abdollahpour, Ibrahim Abedi, Aidin Abedi, Parisa Abegaz, Kedir Hussein Abolhassani, Hassan Abosetugn, Akine Eshete Aboyans, Victor Abrams, Elissa M. Abreu, Lucas Guimarães Abrigo, Michael R.M. Abu Haimed, Abdulaziz Khalid Abualhasan, Ahmed Abu-Gharbieh, Eman Abu-Raddad, Laith Jamal Abushouk, Abdelrahman I. Acebedo, Alyssa Ackerman, Ilana N. Adabi, Maryam Adair, Tim Adamu, Abdu A. Adebayo, Oladimeji M. Adedeji, Isaac Akinkunmi Adekanmbi, Victor Adelson, Jaimie D. Adeoye, Abiodun Moshood Adetokunboh, Olatunji O. Adham, Davoud Advani, Shailesh M. Afarideh, Mohsen Afshari, Mahdi Afshin, Ashkan Agardh, Emilie E. Agarwal, Gina Agasthi, Pradyumna Agesa, Kareha M. Aghaali, Mohammad Aghamir, Seyed Mohammad Kazem Agrawal, Anurag Ahmad, Tauseef Ahmadi, Alireza Ahmadi, Keivan Ahmadi, Mehdi Ahmadieh, Hamid Ahmadpour, Ehsan Ahmed, Muktar Beshir Aji, Budi Akalu, Temesgen Yihunie Akinyemi, Rufus Olusola Akinyemiju, Tomi Akombi, Blessing Akunna, Chisom Joyqueenet Alahdab, Fares Al-Aly, Ziyad Alam, Khurshid Alam, Noore Alam, Samiah Alam, Tahiya Alanezi, Fahad Mashhour Alanzi, Turki M. Albertson, Samuel B. Alcalde-Rabanal, Jacqueline Elizabeth Alema, Niguse Meles Alemu, Biresaw Wassihun Alemu, Yihun Mulugeta Alhabib, Khalid F. Alhassan, Robert Kaba Ali, Muhammad Ali, Saqib Alicandro, Gianfranco Alijanzadeh, Mehran Alinia, Cyrus Alipour, Vahid Alizade, Hesam Aljunid, Syed Mohamed Alla, François Allebeck, Peter Almadi, Majid Abdulrahman Hamad Almasi, Ali Almasi-Hashiani, Amir Almasri, Nihad A. Al-Mekhlafi, Hesham M. Almulhim, Abdulaziz M. Alonso, Jordi Al-Raddadi, Rajaa M. Altirkawi, Khalid A. Alumran, Arwa Khalid Alvis-Guzman, Nelson Alvis-Zakzuk, Nelson J. Amare, Azmeraw T. Amare, Bekalu Amini, Saeed Amini-Rarani, Mostafa Aminorroaya, Arya Amiri, Fatemeh Amit, Arianna Maever L. Amugsi, Dickson A. Amul, Gianna Gayle Herrera Anbesu, Etsay Woldu Ancuceanu, Robert Anderl Department of Juridical and Economic Studies La Sapienza University Rome Italy Department of Infectious Disease Epidemiology London School of Hygiene and Tropical Medicine London United Kingdom Social Determinants of Health Research Center Tehran Iran Department of Neurology Cairo University Cairo Egypt School of Pharmacy Tehran Iran The Institute of Pharmaceutical Sciences (TIPS) Tehran Iran Neuroscience Research Center Isfahan University of Medical Sciences Isfahan Iran Biostatistics Department Near East University Nicosia Cyprus Biostatistics and Health Informatics Madda Walabu University Bale Robe Ethiopia Research Center for Immunodeficiencies Tehran Iran Karolinska University Hospital Huddinge Sweden Department of Cardiology Dupuytren University Hospital Limoges France University of Limoges Limoges France Department of Pediatric Dentistry Federal University of Minas Gerais Belo Horizonte Brazil Department of Research Philippine Institute for Development Studies Quezon City Philippines Department of Healthcare Policy and Research Weill Cornell Medical College in Qatar Doha Qatar Harvard Medical School Boston MA United States Department of Medicine Ain Shams University Cairo Egypt Hamadan University of Medical Sciences Hamadan Iran School of Medicine Cardiff University Cardiff United Kingdom School of Laboratory Medicine and Science University College Hospital Ibadan Ibadan Nigeria Institute of Cardiovascular Diseases University of Ibadan Ibadan Nigeria Centre of Excellence for Epidemiological Modelling and Analysis Stellenbosch University Cape Town South Africa Department of Global Health Stellenbosch University Cape Town South Africa School of Health Ardabil University of Medical Science Ardabil Iran Social Behavioral Research Branch National Institute of Health Bethesda MD United States Department of Oncology Georgetown University Washington DC DC United States Department of Health Metrics Sciences School of Medicine Seattle WA

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw value

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Solving nonlinear direct and inverse transient heat conduction problems by means of Trefftz functions

Solving nonlinear direct and inverse transient heat conducti...

引用

Joint International Conference on Trefftz Method Ⅶ and Method of Fundamental Solutions Ⅲ(Trefftz/MFS 2015)

作者： Krzysztof Grysa Artur Maciag Patrycja Krzyszkowska Kielce University of Technology Faculty of Management and Computer Modelling Kielce University of Technology Faculty of Mechatronics and Mechanical Engineering

In the paper nonlinear direct and inverse transient heat conduction problems are considered. The nonlinearity has been treated by Kirchhoff transformation. Obtained linear problem has been solved by means of Trefftz functions. In this case there are heat polynomials. The solution has been obtained globally in entire time space domain and by means of different variants of Finite Element Method with Trefftz base function(FEMT). Three variants of FEMT are used: continuous(classical FEM with Trefftz base functions), non-continuous(Trefftz base functions without continuity in nodes) and substructuring(nodeless FEMT). The sensitiveness of the method according to data disturbance has been checked. This approach allows to solve direct and inverse heat conduction problems as well.

关键词： Non-linear transient heat conduction Boundary inverse problems Heat polynomials Trefftz base functions Kirchhoff transformation FEMT

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Trefftz method in solving nonlinear coefficient inverse heat conduction problems

Trefftz method in solving nonlinear coefficient inverse heat...

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Joint International Conference on Trefftz Method Ⅶ and Method of Fundamental Solutions Ⅲ(Trefftz/MFS 2015)

作者： Krzysztof Grysa Artur Maciag Magdalena Walaszczyk Kielce University of Technology Faculty of Management and Computer Modelling Kielce University of Technology Faculty of Mechatronics and Mechanical Engineering

The homotopy perturbation method(HPM) is employed to find an approximate solution of an inverse nonlinear nonstationary problem with unknown thermal conductivity coefficient with the prescribed boundary conditions on a part of the boundary and with some measured or anticipated values of the solution in some inner points. The coefficients are assumed to have a form of a linear function of temperature with unknown coefficients. The number of Trefftz functions in HPM is chosen this way to obtain the best fitting of the approximate solution to the input data. Minimization of the difference between the input data and the approximate solution of the problem, leads to the coefficients describing an approximate solution and to the form of the thermal conductivity coefficient.

关键词： Non-linear transient heat conduction HPM Trefftz functions Thermal conductivity Inverse problem

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Simulation of Reynolds number influence on heat exchange in turbulent flow of medium slurry

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Journal of Physics: Conference Series 2016年第1期760卷

作者： A Bartosik Kielce University of Technology Faculty of Management and Computer Modelling Al. Tysiąclecia P.P. 7 25-314 Kielce Poland

The paper deals with the numerical simulation of mass and heat exchange in turbulent flow of solid-liquid mixture in the range of averaged solid particle diameter from 0.10mm to 0.80mm, named further as the medium slurry. Physical model assumes that dispersed phase is fully suspended and a turbulent flow is hydro-dynamically, and thermally developed in a straight horizontal pipeline. Taking into account the aforementioned assumptions the slurry is treated as a single-phase flow with increased density, while viscosity is equals to a carrier liquid viscosity. The mathematical model constitutes time averaged momentum equation in which the turbulent stress tensor was designated using a two-equation turbulence model, which makes use of the Boussinesq eddy-viscosity hypothesis. Turbulence damping function in the turbulence model was especially designed for the medium slurry. In addition, an energy equation has been used in which a convective term was determined from the energy balance acting on a unit pipe length, assuming linear changes of temperature in main flow direction. Finally, the mathematical model of non-isothermal medium slurry flow comprises four partial differential equations, namely momentum and energy equations, equations of kinetic energy of turbulence and its dissipation rate. Four partial differential equations were solved by a finite difference scheme using own computer code. The objective of the paper is to examine the influence of Reynolds number on temperature profiles and Nusselt number in turbulent flow of medium slurry in the range of solids concentration from 0% to 30% by volume. The effect of influential factors on heat transfer between the pipe and slurry is analysed. The paper demonstrates substantial impact of Reynolds number and solids volume fraction on the Nusselt number. The results of numerical simulation are reviewed.

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A study of the flow boiling heat transfer in a minichannel for a heated wall with surface texture produced by vibration-assisted laser machining

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Journal of Physics: Conference Series 2016年第3期745卷

作者： Magdalena Piasecka Kinga Strąk Beata Maciejewska Bogusław Grabas Faculty of Mechatronics and Mechanical Engineering Faculty of Management and Computer Modelling Kielce University of Technology Al. 1000-lecia P.P. 7 PL-25-314 Kielce Poland

The paper presents results concerning flow boiling heat transfer in a vertical minichannel with a depth of 1.7 mm and a width of 16 mm. The element responsible for heating FC-72, which flowed laminarly in the minichannel, was a plate with an enhanced surface. Two types of surface textures were considered. Both were produced by vibration-assisted laser machining. Infrared thermography was used to record changes in the temperature on the outer smooth side of the plate. Two-phase flow patterns were observed through a glass pane. The main aim of the study was to analyze how the two types of surface textures affect the heat transfer coefficient. A two-dimensional heat transfer approach was proposed to determine the local values of the heat transfer coefficient. The inverse problem for the heated wall was solved using a semi-analytical method based on the Trefftz functions. The results are presented as relationships between the heat transfer coefficient and the distance along the minichannel length and as boiling curves. The experimental data obtained for the two types of enhanced heated surfaces was compared with the results recorded for the smooth heated surface. The highest local values of the heat transfer coefficient were reported in the saturated boiling region for the plate with the type 1 texture produced by vibration-assisted laser machining.

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Erratum to: Theories in Business and Information Systems Engineering

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Business & Information Systems Engineering 2016年第5期58卷 327-328页

作者： Martin Bichler Ulrich Frank David Avison Julien Malaurent Peter Fettke Dirk Hovorka Jan Krämer Daniel Schnurr Benjamin Müller Leena Suhl Bernhard Thalheim Department of Informatics Technical University of Munich Garching/Munich Germany Chair of Information Systems and Enterprise Modelling Institute for Computer Science and Business Information Systems University of Duisburg-Essen Essen Germany Department of Information Systems Decision Sciences and Statistics ESSEC Business School Cergy Pontoise Cedex France German Research Center for Artificial Intelligence (DFKI GmbH) and Saarland University Saarbrücken Germany Business Information Systems The University of Sydney Business School The University of Sydney Sydney Australia Chair of Internet and Telecommunications Business Faculty of Business Administration and Economics University of Passau Passau Germany Innovation Management and Strategy Faculty of Economics and Business University of Groningen Groningen The Netherlands Decision Support and Operations Research Lab Department Business Information Systems Universität Paderborn Paderborn Germany Information Systems Engineering (ISE) Institut für Informatik Christian-Albrechts-Universität zu Kiel Kiel Germany

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Dynamic analysis of torsional discrete-continuous systems with position-dependent variable inertia

Journal of Theoretical and Applied Mechanics (Poland)

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Journal of Theoretical and Applied Mechanics (Poland) 2014年第1期52卷 107-115页

作者： Pielorz, Amalia Kielce University of Technology Faculty of Management and Computer Modelling Kielce Poland

In the paper, dynamic investigations of multi-mass discrete-continuous systems torsionally deformed are performed taking into account the position-dependent mass moment of inertia of one of rigid bodies. It is assumed that the rigid body representing a motor moves with a variable velocity. An originally nonlinear problem is linearized, and the wave approach leading to solving equations with a retarded argument having variable coefficients is used for the solution. Exemplary numerical calculations are done for a three-mass system.

关键词： Nonlinear equations

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