Daniel Lepadatu - Academia.edu (original) (raw)

Papers by Daniel Lepadatu

Research paper thumbnail of Multicriterial Investment Analysis and Environmental Impact on the Longest Suspension Bridge from Romania

SGEM International Multidisciplinary Scientific GeoConference� EXPO Proceedings

The process of selecting and prioritizing investment project proposals in construction is charact... more The process of selecting and prioritizing investment project proposals in construction is characterized by multiple objectives and uncertainties due to incomplete information and the multitude and dynamics of factors that can intervene. Knowing their significance and influence on the final investment decision, it is a complex problem that requires a multi-critical analysis with both quantitative and qualitative factors, necessary for a good quantification and evaluation. In recent years, the increase in the complexity of projects involves a large number of factors that ensure the technical and economic success of infrastructure investments and therefore it is necessary to identify the optimal decision criteria in their selection and prioritization. Identifying and setting these criteria is generally difficult and depends on the professional skills of the project manager but should follow a systematic process to ensure its validity and transparency. The paper presents such an analysi...

Research paper thumbnail of Multicriterial optimization of topo-geodetic techniques for behaviour monitoring in service stage of civil engineering structures

IOP conference series, Jun 6, 2020

Optimization of civil engineering systems is a complex process that includes both theoretical and... more Optimization of civil engineering systems is a complex process that includes both theoretical and practical knowledge of experts from different disciplines. Optimization is defined as a rigorous process by which the methods corresponding to an engineering problem are analyzed and selected. The objective of this scientific paper is to define an optimal system / technique in monitoring the behaviour of civil engineering structures by topographic methods using the multi-criterial decision theory, by analyzing, combining and comparing some topographic methods and techniques used in monitoring the behavior of objectives by identifying decisional criteria (quantitative and qualitative) and applying one-or multi-criteria decisions. Finally, by choosing quantitative and qualitative criteria, we can establish the optimal techniques that correspond to the monitoring activity of the behaviour in service stage of civil engineering structures. The necessity for this optimal system that uses an algorithm is to reduce the risks and uncertainties that may arise from the monitoring process of buildings. Also, the results obtained must fulfil a certain accuracy, time and cost conditions, as well as their extent for other monitoring activities in topographical measurements.

Research paper thumbnail of Optimisation of Several Estimating Functions by Multicriterial Analysis of Civil Engineering Structure in Service Stage Monitoring

Zenodo (CERN European Organization for Nuclear Research), Oct 6, 2022

In order to ensure the safety of engineering structures and especially those with special regimen... more In order to ensure the safety of engineering structures and especially those with special regimen such as the viaducts requiring careful monitoring of spatial displacements, it is necessary to find an optimal combination of criteria that are evaluated by a multi-criteria analysis to avoid major structural degradation and their effects on of the entire structure that can generate catastrophes with major losses of human lives. In this paper we will present an optimization of the estimation functions of the evaluation criteria behaviour for the time monitoring of an engineering structure. In this paper, we are analysing a structure that has 50 years and that has a vital significance for Galati city from Romania. It is a 1.3 km-long viaduct structure connecting the city of Galati with ArcelorMittal steel company. The current legislation requires a plan for permanent monitoring of displacement in order to avoid accidents that can lead to loss of human life. Thus, we will quantify and discuss the effects of the different evaluation criteria behaviour and we will choose those that maximize the user's chances of responding without departing from those values that keep their study credible. In order to obtain the results of the multicriteria analysis, three monitoring cycles with three types of instruments on more than 30 tracking points were designed and performed.

Research paper thumbnail of Photovoltaic panels cost optimization with flexible polymer semiconductor cells using fuzzy logic

IOP Conference Series: Materials Science and Engineering, 2019

This paper presents the research undertaken by the authors to determine the parameters of electri... more This paper presents the research undertaken by the authors to determine the parameters of electric power produced by a photovoltaic panel using flexible semiconductor polymer cells, aiming a comparative study between this panel and other types of conventional photovoltaic panels, with monocrystalline, polycrystalline and amorphous silicon, based on technical and economic indicators, established under uncertainty conditions. We will also present the variation of these dimensions according to the incidence angle of solar radiation. Thus, researches will show that for its value between 36-38 degrees, you get very good conversion yields. The economic study presented also reveals that under uncertainty there is a correspondence between the panel type and its physical and economic characteristics.

Research paper thumbnail of Corrosion - An Undesirable Phenomenon for Reinforcement of Advanced Mortars and Concrete

Zenodo (CERN European Organization for Nuclear Research), Oct 6, 2022

Research paper thumbnail of Advanced Design for Experimental Optimisation of Physico-Mechanical Characteristics of Sustainable Local Hemp Concrete

Sustainability

The meaning of technological progress is to produce economic development and to increase the leve... more The meaning of technological progress is to produce economic development and to increase the level of personal comfort. Sustainability can only be achieved if, at the microsystem level as well as at the macrosystem level, the secondary effects of the activities undertaken by people on the environment are in a state of neutrality compared to the impact they can produce on natural conditions. This neutrality can be intrinsic or can be achieved through coercive and compensatory measures. If we take into account the production of carbon dioxide that accompanies a product from the stages of conceptualisation, design, procurement of materials, execution, operation, maintenance, decommissioning and recycling the waste produced at the end of use, then nothing can be sustainable in pure form. Nevertheless, there are products whose production, both as a raw material and as a technological process, can be neutral in terms of carbon emissions. Moreover, they can even become carbon negative over...

Research paper thumbnail of Statistical Analysis of Preliminary Studies for Hemp Concrete

Journal of Applied Life Sciences and Environment

Waste is a major worldwide problem and its recycling has become mandatory in the current context ... more Waste is a major worldwide problem and its recycling has become mandatory in the current context of the decrease in natural resources. The management of recyclable waste improves the efficiency of any economic activities and the impact on the environment decreases proportionally to the quantities reused. With a significant impact on carbon dioxide emissions, the construction sector is one of the largest consumers of energy and raw materials. Hemp, and other biomass waste, are by-products in agriculture, making important contributions to the development of ecological materials by incorporating important quantities of such recyclable waste. This paper presents a series of different hemp concrete compositions that aim to obtain the optimum ratio between the binder and hemp shiv, in order to determine the inflection point towards which the delimitation can be made between insulating materials and materials with improved mechanical resistance. The importance of the work is given by the f...

Research paper thumbnail of Topo-geodetic tools optimisation for efficientely behaviour monitoring in service stage of civil engineering structures

Monitoring the behavior in service stage of civil engineering structures is absolutely necessary ... more Monitoring the behavior in service stage of civil engineering structures is absolutely necessary for ensuring stability and safety through their exploitation. Achievement of an efficient monitoring process of structures is done by using modern topo-geodetic methods and techniques which guarantees the correctness of the data with the highest accuracy of the obtained results. The progress of the equipment area for determining geometric elements, means of calculation and reporting data influences the upgrade of methods and procedures in topographic measurements. The purpose of this paper is to implement the theory of decision using qualitative and quantitative criteria in a cycle of observations in monitoring the behavior in time of a viaduct engineering structure using three different topographical devices. We proposed a comparative analysis using three topo-geodetic technologies for monitoring vertical spatial displacements. The accuracy with which the monitoring marks are determined...

Research paper thumbnail of Rezistența La Coroziune Nitrică a Unor Mortare Speciale Cu Conținut Ridicat De Zgură Nitric Corrosion Resistance of Special Mortars with High Slag Content

Constructions composed of mortars and cement concretes are exposed to advanced nitrate ion corros... more Constructions composed of mortars and cement concretes are exposed to advanced nitrate ion corrosion processes if they are used in aggressive mediums, specific to nitrogen fertilizer industry. The paper aims at tracking down the behavior of cement mortars with a high content of slag (75%) exposed to nitrate ion corrosion as well as carrying out a analysis that might reveal the time evolution of mechanical strength of the standard mortar samples or of those containing slag, when they are submerged in various aggressive solutions. Corrosive agents, acting on the above mentioned items are in particular nitrogen oxides and ammonia gas. These compounds are found in considerable amounts in the atmospheric feature of this type of industry and their effect is intensified by an accidental increase of humidity, temperature, or steam, or unexhausted corrosive gases accompanied, possibly, by inadequate ventilation. The analysis of complex chemical processes enables the highlighting of the influ...

Research paper thumbnail of The Performing of the Civil Engineering and Building Services Faculty’s Topographic Network and the Inventory of Its Spatial Co-Ordinates

This paper describes a methodology to perform the local proper network of supporting points in or... more This paper describes a methodology to perform the local proper network of supporting points in order to be used in practical applications of Surveying discipline. The usefulness of these points is obvious by the fact that it involves greater responsibility in addressing land measurement techniques and puts the students in a real situation with the opportunity at any time to verify the measurement’s results. Also topographic points will be used as benchmarks to intime monitoring of the buildings behavior surrounding the Faculty of Civil Engineering and Building Services. In order to determine the coordinates of the new points was used GNSS Permanent Stations National Network using RTK method: RTCM (Radio Technical Commission for Maritime Services). Measurements were performed with GPS SOUTH S82T, whose field book has implemented software transcomputation real-time geographic coordinates obtained in STEREO-70 coordinate system. Network of permanent GNSS stations has used fixed station...

Research paper thumbnail of Smart technology optimization by multicriteria analysis of civil engineering structure in service stage through topo-geodetic monitoring

Proceedings of the 4th International Conference on Smart City Applications, 2019

EasyChair preprints are intended for rapid dissemination of research results and are integrated w... more EasyChair preprints are intended for rapid dissemination of research results and are integrated with the rest of EasyChair.

Research paper thumbnail of Advanced systems for heat treatment controlling of electrical furnaces

IOP Conference Series: Materials Science and Engineering, 2019

This paper presents a modern electric heat treatment which has implemented an electric furnace co... more This paper presents a modern electric heat treatment which has implemented an electric furnace control system through thermoregulatory with PID control laws. An important aspect is the development of a mathematical model for controlling electrical heating systems for heat treatments based on mathematical modelling to predict the mechanical properties and structure of the play resulting from heat treatment. Validation of the experimental research of heat treatment designed by the mathematical model for predicting mechanical properties and structure of the finished part and model for controlling electrical heating system based on PID adjustment algorithms consists in structural analysis to determine the chemical composition, structural analysis by light microscopy, electron microscopy SEM and EDX quantitative analysis, determination of hardness alloys and physical and mechanical of the turbine blades component of a plasma torch on hydrogen made of heat-treated steel.

Research paper thumbnail of Advanced tools for optimization and efficiently monitoring behaviour in service stage of buildings using renewable energy

IOP Conference Series: Materials Science and Engineering, 2019

In the topographical surveying works devices have got among the required accessories also tools c... more In the topographical surveying works devices have got among the required accessories also tools called tripod. They have the role of correctly installing and settling the equipment above the station point in order to perform the measurements. Various types of tripods are known: the classic tripod (made from aluminum or wood), the adjustable laser tripod, the elevator tripod, the tripod for supporting and adjusting the picket. The aim of this scientific paper is to present my invention that is concerned on a new type of tripod device with photovoltaic cells called mobile solar tripod which has the purpose of providing the energy needed for the equipment used and thus extending the duration of survey measurements by using renewable energies. The tripod being an almost universal accessory along with other topographic instruments, it can be used for some topo-geodetic activities such as monitoring behavior in service stage of buildings, marking the points on the ground, determining ground elevations and other works that require a long time for the objects studied. This present work will describe the advantages and disadvantages of using the existing tripods compared to the new proposed device.

Research paper thumbnail of Civil Engineering and Building Service Topographic Permanent Landmarks Network. Spatial Coordinate Optimization

Present Environment and Sustainable Development, 2016

Sustainable development is a modern concept of adaptation conditions for achieving objectives tha... more Sustainable development is a modern concept of adaptation conditions for achieving objectives that respond simultaneously to at least three major requirements: economic, social and environmental. Achieving sustainable development cannot be accomplished without a change of mentality of people and without communities able to use resources rationally and efficiently. For an efficient application programs surveying topography discipline the students have imagined and created a network of local topographic permanent terminals required for reporting the rectangular coordinates of applications. In order to obtain more accurate values of these coordinates we have made several types of measurements that will be presented in detail in this work.The aim of this paper is to optimize the locating terminals coordinates of the points of our faculty, initially determined using GPS technology. Additional measurements were performed in an interval of one year using a total station. Considering that f...

Research paper thumbnail of Springback of Stamping Process Optimization Using Response Surface Methodology and Interval Computation

Quality Technology & Quantitative Management, 2009

In manufacturing process, the quality of final products is significantly affected by both product... more In manufacturing process, the quality of final products is significantly affected by both product design and process variables. However, historically tolerance research primarily focused on allocating tolerances based on product design characteristics of each component. This work proposes to expand the current tolerancing practices, and presents a new optimization method of tolerancing mechanical systems using interval computation for the prediction of system response. The proposed methodology is based on the development and integration of three concepts in process optimization: mechanical tolerancing, response surface methodology, and interval computation method. An industry case study is used to illustrate the proposed approach.

Research paper thumbnail of A New Response Surface Method for Manufacturing Process Optimization Using Interval Computation

IFAC Proceedings Volumes, 2005

In manufacturing process, the quality of final products is significantly affected by both product... more In manufacturing process, the quality of final products is significantly affected by both product design and process variables. However, historically tolerance research primarily focused on allocating tolerances based on product design characteristics of each component. This work proposes to expand the current tolerancing practices, and presents a new optimization method of tolerancing mechanical systems using interval computation for the prediction of system response. The proposed methodology is based on the development and integration of three concepts in process optimization: mechanical tolerancing, response surface methodology, and interval computation method. An industry case study is used to illustrate the proposed approach.

Research paper thumbnail of Mechanical Characteristics Investigation of Polymer Concrete Using Mixture Design of Experiments and Response Surface Method

Journal of Applied Sciences, 2008

Research paper thumbnail of Ductile damage variation analysis during metal extrusion process using design of experiment technique

International Journal of Vehicle Design, 2005

ABSTRACT In this work, the design of experiments method has been used for a better understanding ... more ABSTRACT In this work, the design of experiments method has been used for a better understanding of the influence of the deviation of the material parameters on the damage evolution within the workpiece. To predict the evolution of the material deterioration during the processes, a damage model accumulation has been implemented in a finite element code and applied with success to simulate damage and crack propagation, which can be generated by the plastic deformation during the operations. The simulation can predict forming defects such as crack initiation and propagation. The mechanical quality of a part is determined by the material property variation such as the hardening and damage states as a result of the increase in strain.

Research paper thumbnail of Optimisation of springback in bending processes using FEM simulation and response surface method

The International Journal of Advanced Manufacturing Technology, 2005

The aim of this work includes the springback optimisation of bending processes using the concept ... more The aim of this work includes the springback optimisation of bending processes using the concept of experimental design and response surface methodology (RSM). The optimisation method includes two phases. The first involves the objective function prediction using design of experiments and response surface method, while the second is an optimisation process using a FORTRAN gradient algorithm. Springback of sheet parts during bending processes is simulated using finite element model (FEM) including damage evolution effects within the sheet. The numerical simulation of the damage evolution has been modelled by means of continuum damage approach. The Lemaitre damage model, taking into account the influence of triaxiality, has been implemented into ABAQUS/Standard code in order to predict the external fibres rupture evolution during the process and the material characteristics changes after bending. The simulation included die corner radius and punch-die clearance as the main variables.

Research paper thumbnail of Statistical investigation of die wear in metal extrusion processes

The International Journal of Advanced Manufacturing Technology, 2005

The aim of this paper is the statistical process control analysis of the tool wear evolution duri... more The aim of this paper is the statistical process control analysis of the tool wear evolution during metal extrusion process for better understanding the principal causes that generate the variability of such a complex phenomenon. The wear prediction is carried out using finite element simulation including the Archard wear model. The tool wear modeling is presented briefly as well as the response surface methodology. The study is based on the application of the central composites designs and allows for the analysis of the response (wear) sensitivity of the tool. The statistical investigation of the process makes it possible to study the influence of each process parameter on the response sensitivity.

Research paper thumbnail of Multicriterial Investment Analysis and Environmental Impact on the Longest Suspension Bridge from Romania

SGEM International Multidisciplinary Scientific GeoConference� EXPO Proceedings

The process of selecting and prioritizing investment project proposals in construction is charact... more The process of selecting and prioritizing investment project proposals in construction is characterized by multiple objectives and uncertainties due to incomplete information and the multitude and dynamics of factors that can intervene. Knowing their significance and influence on the final investment decision, it is a complex problem that requires a multi-critical analysis with both quantitative and qualitative factors, necessary for a good quantification and evaluation. In recent years, the increase in the complexity of projects involves a large number of factors that ensure the technical and economic success of infrastructure investments and therefore it is necessary to identify the optimal decision criteria in their selection and prioritization. Identifying and setting these criteria is generally difficult and depends on the professional skills of the project manager but should follow a systematic process to ensure its validity and transparency. The paper presents such an analysi...

Research paper thumbnail of Multicriterial optimization of topo-geodetic techniques for behaviour monitoring in service stage of civil engineering structures

IOP conference series, Jun 6, 2020

Optimization of civil engineering systems is a complex process that includes both theoretical and... more Optimization of civil engineering systems is a complex process that includes both theoretical and practical knowledge of experts from different disciplines. Optimization is defined as a rigorous process by which the methods corresponding to an engineering problem are analyzed and selected. The objective of this scientific paper is to define an optimal system / technique in monitoring the behaviour of civil engineering structures by topographic methods using the multi-criterial decision theory, by analyzing, combining and comparing some topographic methods and techniques used in monitoring the behavior of objectives by identifying decisional criteria (quantitative and qualitative) and applying one-or multi-criteria decisions. Finally, by choosing quantitative and qualitative criteria, we can establish the optimal techniques that correspond to the monitoring activity of the behaviour in service stage of civil engineering structures. The necessity for this optimal system that uses an algorithm is to reduce the risks and uncertainties that may arise from the monitoring process of buildings. Also, the results obtained must fulfil a certain accuracy, time and cost conditions, as well as their extent for other monitoring activities in topographical measurements.

Research paper thumbnail of Optimisation of Several Estimating Functions by Multicriterial Analysis of Civil Engineering Structure in Service Stage Monitoring

Zenodo (CERN European Organization for Nuclear Research), Oct 6, 2022

In order to ensure the safety of engineering structures and especially those with special regimen... more In order to ensure the safety of engineering structures and especially those with special regimen such as the viaducts requiring careful monitoring of spatial displacements, it is necessary to find an optimal combination of criteria that are evaluated by a multi-criteria analysis to avoid major structural degradation and their effects on of the entire structure that can generate catastrophes with major losses of human lives. In this paper we will present an optimization of the estimation functions of the evaluation criteria behaviour for the time monitoring of an engineering structure. In this paper, we are analysing a structure that has 50 years and that has a vital significance for Galati city from Romania. It is a 1.3 km-long viaduct structure connecting the city of Galati with ArcelorMittal steel company. The current legislation requires a plan for permanent monitoring of displacement in order to avoid accidents that can lead to loss of human life. Thus, we will quantify and discuss the effects of the different evaluation criteria behaviour and we will choose those that maximize the user's chances of responding without departing from those values that keep their study credible. In order to obtain the results of the multicriteria analysis, three monitoring cycles with three types of instruments on more than 30 tracking points were designed and performed.

Research paper thumbnail of Photovoltaic panels cost optimization with flexible polymer semiconductor cells using fuzzy logic

IOP Conference Series: Materials Science and Engineering, 2019

This paper presents the research undertaken by the authors to determine the parameters of electri... more This paper presents the research undertaken by the authors to determine the parameters of electric power produced by a photovoltaic panel using flexible semiconductor polymer cells, aiming a comparative study between this panel and other types of conventional photovoltaic panels, with monocrystalline, polycrystalline and amorphous silicon, based on technical and economic indicators, established under uncertainty conditions. We will also present the variation of these dimensions according to the incidence angle of solar radiation. Thus, researches will show that for its value between 36-38 degrees, you get very good conversion yields. The economic study presented also reveals that under uncertainty there is a correspondence between the panel type and its physical and economic characteristics.

Research paper thumbnail of Corrosion - An Undesirable Phenomenon for Reinforcement of Advanced Mortars and Concrete

Zenodo (CERN European Organization for Nuclear Research), Oct 6, 2022

Research paper thumbnail of Advanced Design for Experimental Optimisation of Physico-Mechanical Characteristics of Sustainable Local Hemp Concrete

Sustainability

The meaning of technological progress is to produce economic development and to increase the leve... more The meaning of technological progress is to produce economic development and to increase the level of personal comfort. Sustainability can only be achieved if, at the microsystem level as well as at the macrosystem level, the secondary effects of the activities undertaken by people on the environment are in a state of neutrality compared to the impact they can produce on natural conditions. This neutrality can be intrinsic or can be achieved through coercive and compensatory measures. If we take into account the production of carbon dioxide that accompanies a product from the stages of conceptualisation, design, procurement of materials, execution, operation, maintenance, decommissioning and recycling the waste produced at the end of use, then nothing can be sustainable in pure form. Nevertheless, there are products whose production, both as a raw material and as a technological process, can be neutral in terms of carbon emissions. Moreover, they can even become carbon negative over...

Research paper thumbnail of Statistical Analysis of Preliminary Studies for Hemp Concrete

Journal of Applied Life Sciences and Environment

Waste is a major worldwide problem and its recycling has become mandatory in the current context ... more Waste is a major worldwide problem and its recycling has become mandatory in the current context of the decrease in natural resources. The management of recyclable waste improves the efficiency of any economic activities and the impact on the environment decreases proportionally to the quantities reused. With a significant impact on carbon dioxide emissions, the construction sector is one of the largest consumers of energy and raw materials. Hemp, and other biomass waste, are by-products in agriculture, making important contributions to the development of ecological materials by incorporating important quantities of such recyclable waste. This paper presents a series of different hemp concrete compositions that aim to obtain the optimum ratio between the binder and hemp shiv, in order to determine the inflection point towards which the delimitation can be made between insulating materials and materials with improved mechanical resistance. The importance of the work is given by the f...

Research paper thumbnail of Topo-geodetic tools optimisation for efficientely behaviour monitoring in service stage of civil engineering structures

Monitoring the behavior in service stage of civil engineering structures is absolutely necessary ... more Monitoring the behavior in service stage of civil engineering structures is absolutely necessary for ensuring stability and safety through their exploitation. Achievement of an efficient monitoring process of structures is done by using modern topo-geodetic methods and techniques which guarantees the correctness of the data with the highest accuracy of the obtained results. The progress of the equipment area for determining geometric elements, means of calculation and reporting data influences the upgrade of methods and procedures in topographic measurements. The purpose of this paper is to implement the theory of decision using qualitative and quantitative criteria in a cycle of observations in monitoring the behavior in time of a viaduct engineering structure using three different topographical devices. We proposed a comparative analysis using three topo-geodetic technologies for monitoring vertical spatial displacements. The accuracy with which the monitoring marks are determined...

Research paper thumbnail of Rezistența La Coroziune Nitrică a Unor Mortare Speciale Cu Conținut Ridicat De Zgură Nitric Corrosion Resistance of Special Mortars with High Slag Content

Constructions composed of mortars and cement concretes are exposed to advanced nitrate ion corros... more Constructions composed of mortars and cement concretes are exposed to advanced nitrate ion corrosion processes if they are used in aggressive mediums, specific to nitrogen fertilizer industry. The paper aims at tracking down the behavior of cement mortars with a high content of slag (75%) exposed to nitrate ion corrosion as well as carrying out a analysis that might reveal the time evolution of mechanical strength of the standard mortar samples or of those containing slag, when they are submerged in various aggressive solutions. Corrosive agents, acting on the above mentioned items are in particular nitrogen oxides and ammonia gas. These compounds are found in considerable amounts in the atmospheric feature of this type of industry and their effect is intensified by an accidental increase of humidity, temperature, or steam, or unexhausted corrosive gases accompanied, possibly, by inadequate ventilation. The analysis of complex chemical processes enables the highlighting of the influ...

Research paper thumbnail of The Performing of the Civil Engineering and Building Services Faculty’s Topographic Network and the Inventory of Its Spatial Co-Ordinates

This paper describes a methodology to perform the local proper network of supporting points in or... more This paper describes a methodology to perform the local proper network of supporting points in order to be used in practical applications of Surveying discipline. The usefulness of these points is obvious by the fact that it involves greater responsibility in addressing land measurement techniques and puts the students in a real situation with the opportunity at any time to verify the measurement’s results. Also topographic points will be used as benchmarks to intime monitoring of the buildings behavior surrounding the Faculty of Civil Engineering and Building Services. In order to determine the coordinates of the new points was used GNSS Permanent Stations National Network using RTK method: RTCM (Radio Technical Commission for Maritime Services). Measurements were performed with GPS SOUTH S82T, whose field book has implemented software transcomputation real-time geographic coordinates obtained in STEREO-70 coordinate system. Network of permanent GNSS stations has used fixed station...

Research paper thumbnail of Smart technology optimization by multicriteria analysis of civil engineering structure in service stage through topo-geodetic monitoring

Proceedings of the 4th International Conference on Smart City Applications, 2019

EasyChair preprints are intended for rapid dissemination of research results and are integrated w... more EasyChair preprints are intended for rapid dissemination of research results and are integrated with the rest of EasyChair.

Research paper thumbnail of Advanced systems for heat treatment controlling of electrical furnaces

IOP Conference Series: Materials Science and Engineering, 2019

This paper presents a modern electric heat treatment which has implemented an electric furnace co... more This paper presents a modern electric heat treatment which has implemented an electric furnace control system through thermoregulatory with PID control laws. An important aspect is the development of a mathematical model for controlling electrical heating systems for heat treatments based on mathematical modelling to predict the mechanical properties and structure of the play resulting from heat treatment. Validation of the experimental research of heat treatment designed by the mathematical model for predicting mechanical properties and structure of the finished part and model for controlling electrical heating system based on PID adjustment algorithms consists in structural analysis to determine the chemical composition, structural analysis by light microscopy, electron microscopy SEM and EDX quantitative analysis, determination of hardness alloys and physical and mechanical of the turbine blades component of a plasma torch on hydrogen made of heat-treated steel.

Research paper thumbnail of Advanced tools for optimization and efficiently monitoring behaviour in service stage of buildings using renewable energy

IOP Conference Series: Materials Science and Engineering, 2019

In the topographical surveying works devices have got among the required accessories also tools c... more In the topographical surveying works devices have got among the required accessories also tools called tripod. They have the role of correctly installing and settling the equipment above the station point in order to perform the measurements. Various types of tripods are known: the classic tripod (made from aluminum or wood), the adjustable laser tripod, the elevator tripod, the tripod for supporting and adjusting the picket. The aim of this scientific paper is to present my invention that is concerned on a new type of tripod device with photovoltaic cells called mobile solar tripod which has the purpose of providing the energy needed for the equipment used and thus extending the duration of survey measurements by using renewable energies. The tripod being an almost universal accessory along with other topographic instruments, it can be used for some topo-geodetic activities such as monitoring behavior in service stage of buildings, marking the points on the ground, determining ground elevations and other works that require a long time for the objects studied. This present work will describe the advantages and disadvantages of using the existing tripods compared to the new proposed device.

Research paper thumbnail of Civil Engineering and Building Service Topographic Permanent Landmarks Network. Spatial Coordinate Optimization

Present Environment and Sustainable Development, 2016

Sustainable development is a modern concept of adaptation conditions for achieving objectives tha... more Sustainable development is a modern concept of adaptation conditions for achieving objectives that respond simultaneously to at least three major requirements: economic, social and environmental. Achieving sustainable development cannot be accomplished without a change of mentality of people and without communities able to use resources rationally and efficiently. For an efficient application programs surveying topography discipline the students have imagined and created a network of local topographic permanent terminals required for reporting the rectangular coordinates of applications. In order to obtain more accurate values of these coordinates we have made several types of measurements that will be presented in detail in this work.The aim of this paper is to optimize the locating terminals coordinates of the points of our faculty, initially determined using GPS technology. Additional measurements were performed in an interval of one year using a total station. Considering that f...

Research paper thumbnail of Springback of Stamping Process Optimization Using Response Surface Methodology and Interval Computation

Quality Technology & Quantitative Management, 2009

In manufacturing process, the quality of final products is significantly affected by both product... more In manufacturing process, the quality of final products is significantly affected by both product design and process variables. However, historically tolerance research primarily focused on allocating tolerances based on product design characteristics of each component. This work proposes to expand the current tolerancing practices, and presents a new optimization method of tolerancing mechanical systems using interval computation for the prediction of system response. The proposed methodology is based on the development and integration of three concepts in process optimization: mechanical tolerancing, response surface methodology, and interval computation method. An industry case study is used to illustrate the proposed approach.

Research paper thumbnail of A New Response Surface Method for Manufacturing Process Optimization Using Interval Computation

IFAC Proceedings Volumes, 2005

In manufacturing process, the quality of final products is significantly affected by both product... more In manufacturing process, the quality of final products is significantly affected by both product design and process variables. However, historically tolerance research primarily focused on allocating tolerances based on product design characteristics of each component. This work proposes to expand the current tolerancing practices, and presents a new optimization method of tolerancing mechanical systems using interval computation for the prediction of system response. The proposed methodology is based on the development and integration of three concepts in process optimization: mechanical tolerancing, response surface methodology, and interval computation method. An industry case study is used to illustrate the proposed approach.

Research paper thumbnail of Mechanical Characteristics Investigation of Polymer Concrete Using Mixture Design of Experiments and Response Surface Method

Journal of Applied Sciences, 2008

Research paper thumbnail of Ductile damage variation analysis during metal extrusion process using design of experiment technique

International Journal of Vehicle Design, 2005

ABSTRACT In this work, the design of experiments method has been used for a better understanding ... more ABSTRACT In this work, the design of experiments method has been used for a better understanding of the influence of the deviation of the material parameters on the damage evolution within the workpiece. To predict the evolution of the material deterioration during the processes, a damage model accumulation has been implemented in a finite element code and applied with success to simulate damage and crack propagation, which can be generated by the plastic deformation during the operations. The simulation can predict forming defects such as crack initiation and propagation. The mechanical quality of a part is determined by the material property variation such as the hardening and damage states as a result of the increase in strain.

Research paper thumbnail of Optimisation of springback in bending processes using FEM simulation and response surface method

The International Journal of Advanced Manufacturing Technology, 2005

The aim of this work includes the springback optimisation of bending processes using the concept ... more The aim of this work includes the springback optimisation of bending processes using the concept of experimental design and response surface methodology (RSM). The optimisation method includes two phases. The first involves the objective function prediction using design of experiments and response surface method, while the second is an optimisation process using a FORTRAN gradient algorithm. Springback of sheet parts during bending processes is simulated using finite element model (FEM) including damage evolution effects within the sheet. The numerical simulation of the damage evolution has been modelled by means of continuum damage approach. The Lemaitre damage model, taking into account the influence of triaxiality, has been implemented into ABAQUS/Standard code in order to predict the external fibres rupture evolution during the process and the material characteristics changes after bending. The simulation included die corner radius and punch-die clearance as the main variables.

Research paper thumbnail of Statistical investigation of die wear in metal extrusion processes

The International Journal of Advanced Manufacturing Technology, 2005

The aim of this paper is the statistical process control analysis of the tool wear evolution duri... more The aim of this paper is the statistical process control analysis of the tool wear evolution during metal extrusion process for better understanding the principal causes that generate the variability of such a complex phenomenon. The wear prediction is carried out using finite element simulation including the Archard wear model. The tool wear modeling is presented briefly as well as the response surface methodology. The study is based on the application of the central composites designs and allows for the analysis of the response (wear) sensitivity of the tool. The statistical investigation of the process makes it possible to study the influence of each process parameter on the response sensitivity.