Ligian Tudoroiu - Academia.edu (original) (raw)
Papers by Ligian Tudoroiu
Romanian Statistical Review Supplement, 2017
This article is devoted to the theoretical and practical construction of a statistical tool inten... more This article is devoted to the theoretical and practical construction of a statistical tool intended to make the hierarchy of the major factors in the large classes of success factors of projects funded by the European Union (EU). After a brief introduction, which briefly explains the concept of critical factors of success, or key success factors (KSF) in the management of such projects, a central section, devoted to methodology and instrumentality, formulates the solution able to draw the hierarchy of classes of critical success factors, and also that of the individualized factors within those classes, and finally in a situation centralized in order to identify the exogenous variables in further econometric models, useful in knowing and anticipating the evolution of the European funds accessed by project managers in the Romanian economy.
Romanian Statistical Review Supplement, 2017
This paper describes a concrete application of the Monte Carlo method for the way the European fu... more This paper describes a concrete application of the Monte Carlo method for the way the European funds were accessed between 2007 and 2013 by the Romanian economy – the economy of a member state of the European Union (EU). In all analyses of simulations there are two waiting areas, placed either at the level of January (16.98 billion Euros), or slightly upward in value, and even above the level of that month (17.09 billion Euros) for the period remained between 31 January 2017 and 31 March 2017, i.e. the last reporting, or the closing of accessing funds by Romania for the period 2007-2013.
Romanian Statistical Review Supplement, 2016
Investigation of voters’ opinions concerning always changing electoral issues, with candidates be... more Investigation of voters’ opinions concerning always changing electoral issues, with candidates belonging to political parties, and also independent candidates of interest to voters in a small town, which was effectively conducted in the year 2016, alongside of the intensely debated theme of the profile of an independent candidate, a potential winner in local elections – that was the synthesis of the research presented in this article, focused on the survey theory, and especially on empathy-caused errors in subjctive or half-guided manner of taking concrete samples. The article manages to emphasize how large can deviations from electoral reality be when sample surveys become subjective, calling on groups of investigators who are part of the candidates’ campaign team.
Proceedings of the 4th World Congress on New Technologies, Aug 1, 2018
E+M Ekonomie a Management, 2017
The authors dealt with fi nding some relevant simulation solutions for the value of the European ... more The authors dealt with fi nding some relevant simulation solutions for the value of the European funds that can be accessed by Romania in the second budget cycle (2014-2020) of the European Union (EU), in which the national economy is participating after the 2007 accession. The article presents, in a brief conceptual introduction, the option for simulation, not only as economical and statistical alternative but also as conceptual and technical method, followed by an analysis section for the EU funds accessed by Romania in the 2007-2013 fi nancial period and in the fi rst three years of 2014-2020 fi nancial period, with a role in generating hypotheses and scenarios of a type of modelling the process of accessing and specifi c absorption (including all types of rates, from the current absorption rate to the actual rate, with revenue in advance, etc.). A methodology section describes the rationale for selecting the method of simulation as Monte Carlo, and also the main hypotheses, detailed scenarios and integrated characteristic variables. The scenario-making eventually shaped three options by combining criteria of stability/instability, nuanced by optimistic/ pessimistic type scenarios. The analysis of the variables described by a probability distribution was conducted statistically on several types of samples simulated by the Monte Carlo method, from 100 draws to 200; 300; 400; and fi nally 500 and 1,000 draws. A presentation of the fi nal simulation results and a number of major comments regarding their calibration, confrontation, clarity and statistical analysis, together with some fi nal remarks as conclusions, limitations and perspectives, end the research approach.
The International Conference on Advanced Materials and Systems, 2018
Bipolymeric composites are widely used to make new materials with predefined properties. Polyamid... more Bipolymeric composites are widely used to make new materials with predefined properties. Polyamide / Polypropylene (PA/PP) based compounds are often subjects of research because both components are relatively cheap, have useful and good properties, and can be processed by melt blending and extrusion-injection technologies, which are time-saving and environment-friendly technologies due to the possibility of reusing the material. Compatibility of binary polymeric compounds can be accomplished by adding a grafted copolymer, the segments of which have physical or chemical affinity with the two immiscible homopolymers. In this paper, maleic anhydride grafted polypropylene (PP-g-MA) was used. Composites having nanofiller are considered as a new generation of composite materials due to their unique properties. To increase the impact resistance of polymer composites (PA / PP-g-MA / PP) dispersion of graphite nanoparticles (nanoG) in polymeric mass was achieved. In addition to the PA / PP-g-MA / PP / nanoG bipolymer nanocomposite obtaining methodology, the combined effects of graphite treatment and compatibiliser polymer (PP-g-MA) on the structure and properties of the composites were studied. A number of optimal receptions have been developed in different technological conditions. Experimental composites have been physico-mechanically characterized by standardized methods specific to plastics and microscopic analysis-SEM.
Procedia Structural Integrity, 2017
During their operation, modern aircraft engine components are subjected to increasingly demanding... more During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.
Romanian Statistical Review Supplement, 2017
This paper is dedicated to the critical factors and major criteria in projects defined as succesf... more This paper is dedicated to the critical factors and major criteria in projects defined as succesfull, based on foreign financing. Almost five decades of existence of such an important organization as Project Management Institute (PMI) were based on project management used simultaneously in scientific and educational area, economic and social support, demographic and humanitarian impact, but more and more professional and multicultural essence of global development of the world. The enthusiasm and dedication of a group of project managers, ingineers, statisticians, economists, sociologists, mathematicians, etc., during two decades, between 1960 and 1980 led to the foundation of the theory of critical factors and major criteria for a success project. The voice of some giants like Dennis P. Slevin, and Jeffrey K. Pinto, deduced from their papers and from their activities and views, as well as from the instrumental, methodological and project manangement education works, have provided, ...
Leather and Footwear Journal, 2018
This paper presents the development of bipolymer nanopolymers-polyamide and polyethylene-compatib... more This paper presents the development of bipolymer nanopolymers-polyamide and polyethylene-compatibilised with polyethylenegraft-maleic anhydride and graphite nanoparticles. Polyamide/polyethylene (PA/PE) composites are studied because both components are relatively inexpensive, advantageous and are processed by injection. Compatibilisation of binary polymer compounds can be accomplished by adding a grafted copolymer, the segments of which have physical or chemical affinity with the two immiscible homopolymers. In this case, polyethylene-graft-maleic anhydride (PE-g-MA) was used. Graphite-containing polymer composites are considered a new generation of materials with predefined properties, in this case, resistance to impact. The combined effects of graphite and compatibilizing polymer (PE-g-MA) were studied on the structure and properties of the new materials. The tested nanocomposites were characterized morpho-structurally (SEM, FT-IR spectrometry) and physico-mechanically. KEY WORDS: nanocomposites, compatibiliser, graphite, morpho-strucutral characterisation, bipolymer NANOCOMPOZITE POLIAMIDĂ/POLIETILENĂ/GRAFIT: REALIZARE ŞI CARACTERIZARE MORFO-STRUCTURALĂ ŞI FIZICO-MECANICĂ REZUMAT. În această lucrare se prezintă realizarea unor nanocompozite bipolimerice-poliamidă şi polietilenă-compatibilizate cu polietilenă grefată cu anhidridă maleică şi nanoparticule de grafit. Compozitele din poliamidă/polietilenă (PA/PE) sunt studiate deoarece ambele componente sunt relativ ieftine, cu proprietăţi avantajoase şi sunt prelucrate prin injecţie. Compatibilizarea compuşilor polimeri binari poate fi realizată prin adăugarea unui copolimer grefat, ale cărui segmente au afinitate fizică sau chimică cu cei doi homopolimeri imiscibili. În acest caz, s-a utilizat polietilenă grefată cu anhidridă maleică (PE-g-MA). Compozitele polimere conţinând grafit sunt considerate o nouă generaţie de materiale cu proprietăţi prestabilite, în acest caz de rezistenţă la impact. Au fost studiate efectele combinate ale grafitului şi polimerul compatibilizator (PE-g-MA) asupra structurii şi proprietăţilor materialelor noi experimentate. Nanocompozitele experimentate au fost caracterizate morfo-structural (SEM, spectrometrie FT-IR) şi fizico-mecanic. CUVINTE CHEIE: nanocompozite, compatibilizator, grafit, caracterizare morfo-structurală, bipolimer NANOCOMPOSITES POLYAMIDE/POLYÉTHYLÈNE/GRAPHITE: RÉALISATION ET CARACTÉRISATION MORPHO-STRUCTURELLE ET PHYSICO-MECANIQUE RÉSUMÉ. Dans cet article on présente la réalisation des nanopcomposites bipolymères-polyamide et polyéthylène-compatibilisés avec le polyéthylène greffé avec de l'anhydride maléique et des nanoparticules de graphite. Les composites polyamide/polyéthylène (PA/PE) sont étudiés car les deux composants sont relativement peu coûteux, avantageux et sont traités par injection. La compatibilité des composés polymères binaires peut être réalisée en ajoutant un copolymère greffé dont les segments ont une affinité physique ou chimique avec les deux homopolymères non miscibles. Dans ce cas, du polyéthylène greffé de l'anhydride maléique (PE-g-MA) a été utilisé. Les composites contenant des graphites contenant des polymères sont considérés comme une nouvelle génération de matériaux aux propriétés prédéfinies, dans ce cas la résistance aux chocs. Les effets combinés du graphite et du polymère compatibilisant (PE-g-MA) ont été étudiés sur la structure et les propriétés des nouveaux matériaux expérimentaux. Les nanocomposites expérimentaux ont été caractérisés du point de vue morphostructurel (MEB, spectrométrie FT-IR) et physico-mécanique.
Romanian Statistical Review Supplement, 2017
This article is devoted to the theoretical and practical construction of a statistical tool inten... more This article is devoted to the theoretical and practical construction of a statistical tool intended to make the hierarchy of the major factors in the large classes of success factors of projects funded by the European Union (EU). After a brief introduction, which briefly explains the concept of critical factors of success, or key success factors (KSF) in the management of such projects, a central section, devoted to methodology and instrumentality, formulates the solution able to draw the hierarchy of classes of critical success factors, and also that of the individualized factors within those classes, and finally in a situation centralized in order to identify the exogenous variables in further econometric models, useful in knowing and anticipating the evolution of the European funds accessed by project managers in the Romanian economy.
Romanian Statistical Review Supplement, 2017
This paper describes a concrete application of the Monte Carlo method for the way the European fu... more This paper describes a concrete application of the Monte Carlo method for the way the European funds were accessed between 2007 and 2013 by the Romanian economy – the economy of a member state of the European Union (EU). In all analyses of simulations there are two waiting areas, placed either at the level of January (16.98 billion Euros), or slightly upward in value, and even above the level of that month (17.09 billion Euros) for the period remained between 31 January 2017 and 31 March 2017, i.e. the last reporting, or the closing of accessing funds by Romania for the period 2007-2013.
Romanian Statistical Review Supplement, 2016
Investigation of voters’ opinions concerning always changing electoral issues, with candidates be... more Investigation of voters’ opinions concerning always changing electoral issues, with candidates belonging to political parties, and also independent candidates of interest to voters in a small town, which was effectively conducted in the year 2016, alongside of the intensely debated theme of the profile of an independent candidate, a potential winner in local elections – that was the synthesis of the research presented in this article, focused on the survey theory, and especially on empathy-caused errors in subjctive or half-guided manner of taking concrete samples. The article manages to emphasize how large can deviations from electoral reality be when sample surveys become subjective, calling on groups of investigators who are part of the candidates’ campaign team.
Proceedings of the 4th World Congress on New Technologies, Aug 1, 2018
E+M Ekonomie a Management, 2017
The authors dealt with fi nding some relevant simulation solutions for the value of the European ... more The authors dealt with fi nding some relevant simulation solutions for the value of the European funds that can be accessed by Romania in the second budget cycle (2014-2020) of the European Union (EU), in which the national economy is participating after the 2007 accession. The article presents, in a brief conceptual introduction, the option for simulation, not only as economical and statistical alternative but also as conceptual and technical method, followed by an analysis section for the EU funds accessed by Romania in the 2007-2013 fi nancial period and in the fi rst three years of 2014-2020 fi nancial period, with a role in generating hypotheses and scenarios of a type of modelling the process of accessing and specifi c absorption (including all types of rates, from the current absorption rate to the actual rate, with revenue in advance, etc.). A methodology section describes the rationale for selecting the method of simulation as Monte Carlo, and also the main hypotheses, detailed scenarios and integrated characteristic variables. The scenario-making eventually shaped three options by combining criteria of stability/instability, nuanced by optimistic/ pessimistic type scenarios. The analysis of the variables described by a probability distribution was conducted statistically on several types of samples simulated by the Monte Carlo method, from 100 draws to 200; 300; 400; and fi nally 500 and 1,000 draws. A presentation of the fi nal simulation results and a number of major comments regarding their calibration, confrontation, clarity and statistical analysis, together with some fi nal remarks as conclusions, limitations and perspectives, end the research approach.
The International Conference on Advanced Materials and Systems, 2018
Bipolymeric composites are widely used to make new materials with predefined properties. Polyamid... more Bipolymeric composites are widely used to make new materials with predefined properties. Polyamide / Polypropylene (PA/PP) based compounds are often subjects of research because both components are relatively cheap, have useful and good properties, and can be processed by melt blending and extrusion-injection technologies, which are time-saving and environment-friendly technologies due to the possibility of reusing the material. Compatibility of binary polymeric compounds can be accomplished by adding a grafted copolymer, the segments of which have physical or chemical affinity with the two immiscible homopolymers. In this paper, maleic anhydride grafted polypropylene (PP-g-MA) was used. Composites having nanofiller are considered as a new generation of composite materials due to their unique properties. To increase the impact resistance of polymer composites (PA / PP-g-MA / PP) dispersion of graphite nanoparticles (nanoG) in polymeric mass was achieved. In addition to the PA / PP-g-MA / PP / nanoG bipolymer nanocomposite obtaining methodology, the combined effects of graphite treatment and compatibiliser polymer (PP-g-MA) on the structure and properties of the composites were studied. A number of optimal receptions have been developed in different technological conditions. Experimental composites have been physico-mechanically characterized by standardized methods specific to plastics and microscopic analysis-SEM.
Procedia Structural Integrity, 2017
During their operation, modern aircraft engine components are subjected to increasingly demanding... more During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.
Romanian Statistical Review Supplement, 2017
This paper is dedicated to the critical factors and major criteria in projects defined as succesf... more This paper is dedicated to the critical factors and major criteria in projects defined as succesfull, based on foreign financing. Almost five decades of existence of such an important organization as Project Management Institute (PMI) were based on project management used simultaneously in scientific and educational area, economic and social support, demographic and humanitarian impact, but more and more professional and multicultural essence of global development of the world. The enthusiasm and dedication of a group of project managers, ingineers, statisticians, economists, sociologists, mathematicians, etc., during two decades, between 1960 and 1980 led to the foundation of the theory of critical factors and major criteria for a success project. The voice of some giants like Dennis P. Slevin, and Jeffrey K. Pinto, deduced from their papers and from their activities and views, as well as from the instrumental, methodological and project manangement education works, have provided, ...
Leather and Footwear Journal, 2018
This paper presents the development of bipolymer nanopolymers-polyamide and polyethylene-compatib... more This paper presents the development of bipolymer nanopolymers-polyamide and polyethylene-compatibilised with polyethylenegraft-maleic anhydride and graphite nanoparticles. Polyamide/polyethylene (PA/PE) composites are studied because both components are relatively inexpensive, advantageous and are processed by injection. Compatibilisation of binary polymer compounds can be accomplished by adding a grafted copolymer, the segments of which have physical or chemical affinity with the two immiscible homopolymers. In this case, polyethylene-graft-maleic anhydride (PE-g-MA) was used. Graphite-containing polymer composites are considered a new generation of materials with predefined properties, in this case, resistance to impact. The combined effects of graphite and compatibilizing polymer (PE-g-MA) were studied on the structure and properties of the new materials. The tested nanocomposites were characterized morpho-structurally (SEM, FT-IR spectrometry) and physico-mechanically. KEY WORDS: nanocomposites, compatibiliser, graphite, morpho-strucutral characterisation, bipolymer NANOCOMPOZITE POLIAMIDĂ/POLIETILENĂ/GRAFIT: REALIZARE ŞI CARACTERIZARE MORFO-STRUCTURALĂ ŞI FIZICO-MECANICĂ REZUMAT. În această lucrare se prezintă realizarea unor nanocompozite bipolimerice-poliamidă şi polietilenă-compatibilizate cu polietilenă grefată cu anhidridă maleică şi nanoparticule de grafit. Compozitele din poliamidă/polietilenă (PA/PE) sunt studiate deoarece ambele componente sunt relativ ieftine, cu proprietăţi avantajoase şi sunt prelucrate prin injecţie. Compatibilizarea compuşilor polimeri binari poate fi realizată prin adăugarea unui copolimer grefat, ale cărui segmente au afinitate fizică sau chimică cu cei doi homopolimeri imiscibili. În acest caz, s-a utilizat polietilenă grefată cu anhidridă maleică (PE-g-MA). Compozitele polimere conţinând grafit sunt considerate o nouă generaţie de materiale cu proprietăţi prestabilite, în acest caz de rezistenţă la impact. Au fost studiate efectele combinate ale grafitului şi polimerul compatibilizator (PE-g-MA) asupra structurii şi proprietăţilor materialelor noi experimentate. Nanocompozitele experimentate au fost caracterizate morfo-structural (SEM, spectrometrie FT-IR) şi fizico-mecanic. CUVINTE CHEIE: nanocompozite, compatibilizator, grafit, caracterizare morfo-structurală, bipolimer NANOCOMPOSITES POLYAMIDE/POLYÉTHYLÈNE/GRAPHITE: RÉALISATION ET CARACTÉRISATION MORPHO-STRUCTURELLE ET PHYSICO-MECANIQUE RÉSUMÉ. Dans cet article on présente la réalisation des nanopcomposites bipolymères-polyamide et polyéthylène-compatibilisés avec le polyéthylène greffé avec de l'anhydride maléique et des nanoparticules de graphite. Les composites polyamide/polyéthylène (PA/PE) sont étudiés car les deux composants sont relativement peu coûteux, avantageux et sont traités par injection. La compatibilité des composés polymères binaires peut être réalisée en ajoutant un copolymère greffé dont les segments ont une affinité physique ou chimique avec les deux homopolymères non miscibles. Dans ce cas, du polyéthylène greffé de l'anhydride maléique (PE-g-MA) a été utilisé. Les composites contenant des graphites contenant des polymères sont considérés comme une nouvelle génération de matériaux aux propriétés prédéfinies, dans ce cas la résistance aux chocs. Les effets combinés du graphite et du polymère compatibilisant (PE-g-MA) ont été étudiés sur la structure et les propriétés des nouveaux matériaux expérimentaux. Les nanocomposites expérimentaux ont été caractérisés du point de vue morphostructurel (MEB, spectrométrie FT-IR) et physico-mécanique.