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radu vasile

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University of Warwick

Hacer Topaktas Ustuner

Istanbul University

The Hebrew University of Jerusalem

Michał Wasiucionek

"Nicolae Iorga" Institute of History

Viacheslav Kuleshov

Stockholm University

Bernardo Vescovi Fabris

Universidade Federal de Ouro Preto

Jaime VALENZUELA MÁRQUEZ

Pontificia Universidad Catolica de Chile

Emodir Research Group

Ege University

Shumen University

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Papers by radu vasile

Wajsberg algebras arising from binary block codes

Soft Computing, Feb 21, 2020

In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras... more In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras, Wajsberg algebras and binary block codes. Using connections between these three algebras, we will associate to each of them a binary block code and, in some circumstances, we will prove that the converse is also true.

$Research paper thumbnail of Wajsberg algebras of order $$n (n\le 9)$$$

Wajsberg algebras of order $$n (n\le 9)$$

Neural Computing and Applications, Dec 23, 2019

Knowing the applications of logical algebras in various fields, such as artificial intelligence o... more Knowing the applications of logical algebras in various fields, such as artificial intelligence or coding theory, in this paper, we study some properties of a special class of such algebras, namely finite Wajsberg algebras. For this purpose, we give a representation theorem for finite Wajsberg algebras and give a formula for the number of non-isomorphic Wajsberg algebras of order n; also we give the total number of finite Wajsberg algebras of order n. Since a big value of n involves a lot of computations, as examples, we present and describe all finite Wajsberg algebras of order $$n\le 9$$ .

Wajsberg algebras of order n, n<=9

arXiv (Cornell University), May 12, 2019

In this paper, we describe all finite Wajsberg algebras of order n ≤ 9.

Assessment of thermal fatigue crack growth in the high cycle domain under sinusoidal thermal loading An application - Civaux 1 case

The Institute for Energy provides scientific and technical support for the conception, developmen... more

A Prospective Study for Probabilistic Approach of Thermal Fatigue in Mixing Tees

The work performs a prospective study on probabilistic approach of thermal fatigue in mixing tees... more The work performs a prospective study on probabilistic approach of thermal fatigue in mixing tees (Civaux 1 damage case) by means of the limit state function and Monte Carlo simulation. It is based on previous work where a deterministic assessment for thermal fatigue crack growth in high-cycle loadings, under the large nonlinear gradient stress profiles through wall-thickness due to sinusoidal thermal loading, has been done. The probabilistic approach considers variability in initial crack depth and Paris law C scaling parameter by means of specific probability density distributions. The crude Monte Carlo Simulations are performed using specific routines implemented in MATLAB software with Statistics Toolbox, and probabilities of failure are derived using the failure function which is defined based on a limit state given by the critical crack depth. The results were checked against predictions from empirical cumulative distribution and a good agreement was found. An important task w...

New Analytical Stress Formulae for Arbitrary Time Dependent Thermal Loads in Pipes

Analytical solutions with several new features have been developed for temperature and elastic th... more Analytical solutions with several new features have been developed for temperature and elastic thermal stress distributions for a hollow circular cylinder under sinusoidal thermal transient loading at the inner surface. The approach uses a finite Hankel transform in a general form for any transient thermal loading for a hollow cylinder. Using the properties of Bessel functions, an analytical solution for temperature distribution through wall thickness was derived for a special case of sinusoidal transient thermal loading on inner pipe surface. The solutions for associated thermal stress components were developed by means of the displacement technique. To the authors’ knowledge, this is first time a complete set of such analytical expressions has been openly published. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC func...

Determination of high temperature material properties of 15-15Ti steel by small specimen techniques

This publication is a Technical report by the Joint Research Centre (JRC), the European Commissio... more This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Test methodologies for determining high temperature material properties of thin walled tubes

Matthias Bruchhausen (JRC) Karl-Fredrik Nilsson (JRC) Rami Pohja (VTT) Eberhard Altstadt (HZDR) M... more Matthias Bruchhausen (JRC) Karl-Fredrik Nilsson (JRC) Rami Pohja (VTT) Eberhard Altstadt (HZDR) Marta Serrano (CIEMAT) Vasile RADU (INR) Carlo Cristalli (ENEA) Jarir Aktaa (KIT) Hygreeva Namburi (CVR) Remi Delville (SCK•CEN) Arnaud Courcelle (CEA) 2017 EUR 28642 EN This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Tensile and creep property determination of 15-15Ti fuel cladding steel by small punch testing

Numerical and Experimental Analysis of the Formabil Ity of 1 . 4301 Austenitic Stainless Steel Sheets Using Hydroformin G

The present paper aims to analyse the forming capac ity of stainless steel materials with hydrofo... more The present paper aims to analyse the forming capac ity of stainless steel materials with hydroforming forming process. For this research, 1.4301 (X5CrNi18-10) austenitic stainless steel has been i n focus for numerical and experimental analysis. The main advertised advantages of this material are eas e of formability, good corrosion resistance and excel lent aesthetic appearance for the end product. For proper forming evaluation tensile test, forming lim it curves – Nakajima test have been carried out. Th e main material mechanical characteristics were proce ssed in order to determine an accurate finite element model. The hydroforming drawn part was formed by a newly developed hydroforming press concept, developed by the authors. The numerical resul ts were compared to the measured experimental results with the help of optical strain measurement s oftware.

New ways for building BCK-algebras of higher order

TBILISI - MATHEMATICS, 2020

Wajsberg algebras arising from binary block codes

Soft Computing, 2020

In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras... more In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras, Wajsberg algebras and binary block codes. Using connections between these three algebras, we will associate to each of them a binary block code and, in some circumstances, we will prove that the converse is also true.

$Research paper thumbnail of Wajsberg algebras of order $$n (n\le 9)$$$

Wajsberg algebras of order $$n (n\le 9)$$

Neural Computing and Applications, 2019

Knowing the applications of logical algebras in various fields, such as artificial intelligence o... more Knowing the applications of logical algebras in various fields, such as artificial intelligence or coding theory, in this paper, we study some properties of a special class of such algebras, namely finite Wajsberg algebras. For this purpose, we give a representation theorem for finite Wajsberg algebras and give a formula for the number of non-isomorphic Wajsberg algebras of order n; also we give the total number of finite Wajsberg algebras of order n. Since a big value of n involves a lot of computations, as examples, we present and describe all finite Wajsberg algebras of order $$n\le 9$$ .

From Old Ciphers to Modern Communications

Advances in Military Technology, 2019

Experimental and numerical investigations of the steel sheets formability with hydroforming

MATEC Web of Conferences, 2017

The present paper focuses on analyzing the forming capacity of steel blanks with hydroforming pro... more The present paper focuses on analyzing the forming capacity of steel blanks with hydroforming process. For this research steel sheets have been in focus for numerical and experimental analysis. The main advantages for this materials are good surface finish, excellent forming capacity and close tolerances, appealing advantages for manufacturers. A finite element model has been developed from data obtained through tensile tests and forming limit curves. A newly developed hydroforming press has been used to carry out the forming experiments. Side-by-side analysis between numerical and experimental results concludes the experiment.

Designing a Die for Hydroforming

ACTA Universitatis Cibiniensis, 2016

Designing a die is in every application field an intensive process of bringing together know how ... more Designing a die is in every application field an intensive process of bringing together know how from design, testing and every-day use from previous dies with the new application requirements. Contribution deals with a knowledge oriented, modular and feature integrated computer aided design system for die development. This paper describes the concepts behind designing a hydroforming die for sheet metal forming, with easy application-use in small workshops for testing hydroforming capabilities of different materials.

Sheet Metal Hydroforming Technology - State-of-the-Art

Applied Mechanics and Materials, 2016

The present paper describes the current status of hydroforming technology in today’s global marke... more The present paper describes the current status of hydroforming technology in today’s global market that focuses on energy use in respect to increasing requirements especially from the automotive industry with its renaissance after the economic crisis. A vast hydroforming classification and the restrictions and drawbacks for a wider market share are also presented.

A case study regarding the implementation of the GDSS in academic and industrial organisations

The idea to build a Group Decision Support System (GDSS) to support the decision makers at all th... more The idea to build a Group Decision Support System (GDSS) to support the decision makers at all the hierarchic levels in an organization to take the decisions efficiently and just in time appeared in the '70. The main advantage of using a GDSS proved to be, over the years, a better understanding of the decision process through the involvement of all the decision makers in all the phases of the decisional issue from statement to solving and interpretation. With time, GDSS turned the collaboration activities into a competitive advantage for all the actors involved: public administration, academic environment and enterprises, contributing to a higher competitiveness in a time when the cooperation between the various organizations and the self-administration plays a key role in a global economy. In this paper, 3 GDSS's developed in research projects and implemented in LBUS (Lucian Blaga University of Sibiu) and other industrial companies are presented and analysed; we come also w...

A study on fatigue crack growth in the high cycle domain assuming sinusoidal thermal loading

International Journal of Pressure Vessels and Piping, 2009

The Institute for Energy provides scientific and technical support for the conception, developmen... more

Development of new analytical solutions for elastic thermal stress components in a hollow cylinder under sinusoidal transient thermal loading

International Journal of Pressure Vessels and Piping, 2008

For the analysis of high-cycle thermal fatigue due to striping (such as has been observed due to ... more For the analysis of high-cycle thermal fatigue due to striping (such as has been observed due to turbulence at mixing tees of class 1-2-3 piping of nuclear power reactors) it can be necessary to consider the time-dependent temperature gradient within the pipe wall thickness rather than just at the surface. To address this, a set of analytical solutions with several new features has been developed for the temperature field and the associated elastic thermal stress distributions for a hollow circular cylinder subjected to sinusoidal transient thermal loading at the inner surface. The approach uses a finite Hankel transform and some properties of Bessel functions. The analytical predictions have been successfully benchmarked by comparison with results from finite element analysis, and also with some results of independent studies.

Wajsberg algebras arising from binary block codes

Soft Computing, Feb 21, 2020

In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras... more In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras, Wajsberg algebras and binary block codes. Using connections between these three algebras, we will associate to each of them a binary block code and, in some circumstances, we will prove that the converse is also true.

$Research paper thumbnail of Wajsberg algebras of order $$n (n\le 9)$$$

Wajsberg algebras of order $$n (n\le 9)$$

Neural Computing and Applications, Dec 23, 2019

Knowing the applications of logical algebras in various fields, such as artificial intelligence o... more Knowing the applications of logical algebras in various fields, such as artificial intelligence or coding theory, in this paper, we study some properties of a special class of such algebras, namely finite Wajsberg algebras. For this purpose, we give a representation theorem for finite Wajsberg algebras and give a formula for the number of non-isomorphic Wajsberg algebras of order n; also we give the total number of finite Wajsberg algebras of order n. Since a big value of n involves a lot of computations, as examples, we present and describe all finite Wajsberg algebras of order $$n\le 9$$ .

Wajsberg algebras of order n, n<=9

arXiv (Cornell University), May 12, 2019

In this paper, we describe all finite Wajsberg algebras of order n ≤ 9.

Assessment of thermal fatigue crack growth in the high cycle domain under sinusoidal thermal loading An application - Civaux 1 case

The Institute for Energy provides scientific and technical support for the conception, developmen... more

A Prospective Study for Probabilistic Approach of Thermal Fatigue in Mixing Tees

The work performs a prospective study on probabilistic approach of thermal fatigue in mixing tees... more The work performs a prospective study on probabilistic approach of thermal fatigue in mixing tees (Civaux 1 damage case) by means of the limit state function and Monte Carlo simulation. It is based on previous work where a deterministic assessment for thermal fatigue crack growth in high-cycle loadings, under the large nonlinear gradient stress profiles through wall-thickness due to sinusoidal thermal loading, has been done. The probabilistic approach considers variability in initial crack depth and Paris law C scaling parameter by means of specific probability density distributions. The crude Monte Carlo Simulations are performed using specific routines implemented in MATLAB software with Statistics Toolbox, and probabilities of failure are derived using the failure function which is defined based on a limit state given by the critical crack depth. The results were checked against predictions from empirical cumulative distribution and a good agreement was found. An important task w...

New Analytical Stress Formulae for Arbitrary Time Dependent Thermal Loads in Pipes

Analytical solutions with several new features have been developed for temperature and elastic th... more Analytical solutions with several new features have been developed for temperature and elastic thermal stress distributions for a hollow circular cylinder under sinusoidal thermal transient loading at the inner surface. The approach uses a finite Hankel transform in a general form for any transient thermal loading for a hollow cylinder. Using the properties of Bessel functions, an analytical solution for temperature distribution through wall thickness was derived for a special case of sinusoidal transient thermal loading on inner pipe surface. The solutions for associated thermal stress components were developed by means of the displacement technique. To the authors’ knowledge, this is first time a complete set of such analytical expressions has been openly published. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC func...

Determination of high temperature material properties of 15-15Ti steel by small specimen techniques

This publication is a Technical report by the Joint Research Centre (JRC), the European Commissio... more This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Test methodologies for determining high temperature material properties of thin walled tubes

Matthias Bruchhausen (JRC) Karl-Fredrik Nilsson (JRC) Rami Pohja (VTT) Eberhard Altstadt (HZDR) M... more Matthias Bruchhausen (JRC) Karl-Fredrik Nilsson (JRC) Rami Pohja (VTT) Eberhard Altstadt (HZDR) Marta Serrano (CIEMAT) Vasile RADU (INR) Carlo Cristalli (ENEA) Jarir Aktaa (KIT) Hygreeva Namburi (CVR) Remi Delville (SCK•CEN) Arnaud Courcelle (CEA) 2017 EUR 28642 EN This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Tensile and creep property determination of 15-15Ti fuel cladding steel by small punch testing

Numerical and Experimental Analysis of the Formabil Ity of 1 . 4301 Austenitic Stainless Steel Sheets Using Hydroformin G

The present paper aims to analyse the forming capac ity of stainless steel materials with hydrofo... more The present paper aims to analyse the forming capac ity of stainless steel materials with hydroforming forming process. For this research, 1.4301 (X5CrNi18-10) austenitic stainless steel has been i n focus for numerical and experimental analysis. The main advertised advantages of this material are eas e of formability, good corrosion resistance and excel lent aesthetic appearance for the end product. For proper forming evaluation tensile test, forming lim it curves – Nakajima test have been carried out. Th e main material mechanical characteristics were proce ssed in order to determine an accurate finite element model. The hydroforming drawn part was formed by a newly developed hydroforming press concept, developed by the authors. The numerical resul ts were compared to the measured experimental results with the help of optical strain measurement s oftware.

New ways for building BCK-algebras of higher order

TBILISI - MATHEMATICS, 2020

Wajsberg algebras arising from binary block codes

Soft Computing, 2020

In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras... more In this paper we presented some connections between BCK-commutative bounded algebras, MV-algebras, Wajsberg algebras and binary block codes. Using connections between these three algebras, we will associate to each of them a binary block code and, in some circumstances, we will prove that the converse is also true.

$Research paper thumbnail of Wajsberg algebras of order $$n (n\le 9)$$$

Wajsberg algebras of order $$n (n\le 9)$$

Neural Computing and Applications, 2019

Knowing the applications of logical algebras in various fields, such as artificial intelligence o... more Knowing the applications of logical algebras in various fields, such as artificial intelligence or coding theory, in this paper, we study some properties of a special class of such algebras, namely finite Wajsberg algebras. For this purpose, we give a representation theorem for finite Wajsberg algebras and give a formula for the number of non-isomorphic Wajsberg algebras of order n; also we give the total number of finite Wajsberg algebras of order n. Since a big value of n involves a lot of computations, as examples, we present and describe all finite Wajsberg algebras of order $$n\le 9$$ .

From Old Ciphers to Modern Communications

Advances in Military Technology, 2019

Experimental and numerical investigations of the steel sheets formability with hydroforming

MATEC Web of Conferences, 2017

The present paper focuses on analyzing the forming capacity of steel blanks with hydroforming pro... more The present paper focuses on analyzing the forming capacity of steel blanks with hydroforming process. For this research steel sheets have been in focus for numerical and experimental analysis. The main advantages for this materials are good surface finish, excellent forming capacity and close tolerances, appealing advantages for manufacturers. A finite element model has been developed from data obtained through tensile tests and forming limit curves. A newly developed hydroforming press has been used to carry out the forming experiments. Side-by-side analysis between numerical and experimental results concludes the experiment.

Designing a Die for Hydroforming

ACTA Universitatis Cibiniensis, 2016

Designing a die is in every application field an intensive process of bringing together know how ... more Designing a die is in every application field an intensive process of bringing together know how from design, testing and every-day use from previous dies with the new application requirements. Contribution deals with a knowledge oriented, modular and feature integrated computer aided design system for die development. This paper describes the concepts behind designing a hydroforming die for sheet metal forming, with easy application-use in small workshops for testing hydroforming capabilities of different materials.

Sheet Metal Hydroforming Technology - State-of-the-Art

Applied Mechanics and Materials, 2016

The present paper describes the current status of hydroforming technology in today’s global marke... more The present paper describes the current status of hydroforming technology in today’s global market that focuses on energy use in respect to increasing requirements especially from the automotive industry with its renaissance after the economic crisis. A vast hydroforming classification and the restrictions and drawbacks for a wider market share are also presented.

A case study regarding the implementation of the GDSS in academic and industrial organisations

The idea to build a Group Decision Support System (GDSS) to support the decision makers at all th... more The idea to build a Group Decision Support System (GDSS) to support the decision makers at all the hierarchic levels in an organization to take the decisions efficiently and just in time appeared in the '70. The main advantage of using a GDSS proved to be, over the years, a better understanding of the decision process through the involvement of all the decision makers in all the phases of the decisional issue from statement to solving and interpretation. With time, GDSS turned the collaboration activities into a competitive advantage for all the actors involved: public administration, academic environment and enterprises, contributing to a higher competitiveness in a time when the cooperation between the various organizations and the self-administration plays a key role in a global economy. In this paper, 3 GDSS's developed in research projects and implemented in LBUS (Lucian Blaga University of Sibiu) and other industrial companies are presented and analysed; we come also w...

A study on fatigue crack growth in the high cycle domain assuming sinusoidal thermal loading

International Journal of Pressure Vessels and Piping, 2009

The Institute for Energy provides scientific and technical support for the conception, developmen... more

Development of new analytical solutions for elastic thermal stress components in a hollow cylinder under sinusoidal transient thermal loading

International Journal of Pressure Vessels and Piping, 2008

For the analysis of high-cycle thermal fatigue due to striping (such as has been observed due to ... more For the analysis of high-cycle thermal fatigue due to striping (such as has been observed due to turbulence at mixing tees of class 1-2-3 piping of nuclear power reactors) it can be necessary to consider the time-dependent temperature gradient within the pipe wall thickness rather than just at the surface. To address this, a set of analytical solutions with several new features has been developed for the temperature field and the associated elastic thermal stress distributions for a hollow circular cylinder subjected to sinusoidal transient thermal loading at the inner surface. The approach uses a finite Hankel transform and some properties of Bessel functions. The analytical predictions have been successfully benchmarked by comparison with results from finite element analysis, and also with some results of independent studies.