Valentin Amortila, E. Mereuta, M. Novetschi, M. Rus, S. Vereşiu
Biomechanical modeling with the help of analytical mechanics together with the application of dedicated IT resources and mechanical simulations lead to a higher accuracy of the biomechanical model. From an analytical point of view, this article develops the equation of motion of the human head in a biomechanical system with three degrees of freedom using the Lagrange equations of the second case. It has been considered that this biomechanical subsystem consists of 3 anatomicalelements: the head, the cervical region and the rest of the spine (considered as being a single element consisting of the thoracic region, lumbar region, sacral region and coccygeal region).The forces which stress the head and spine during normal movements or when activities in the workplace are performed make biomechanical modeling different. Therefore, the movement of the subsystem was analyzed in the sagittal plane taking into consideration joints of cylindroid type, and the subsystem as a triple inverted pendulum.The main purpose of this model was to obtain the differential equations of motion of the mechanical subsystem considered to be in the matrix-analytical form.
{"title":"ANALYTIC MODEL OF THE SUBSYSTEM HEAD-NECK-SPINE MOVEMENT BIOMECHANICS","authors":"Valentin Amortila, E. Mereuta, M. Novetschi, M. Rus, S. Vereşiu","doi":"10.35219/mtd.2021.1.03","DOIUrl":"https://doi.org/10.35219/mtd.2021.1.03","url":null,"abstract":"Biomechanical modeling with the help of analytical mechanics together with the application of dedicated IT resources and mechanical simulations lead to a higher accuracy of the biomechanical model. From an analytical point of view, this article develops the equation of motion of the human head in a biomechanical system with three degrees of freedom using the Lagrange equations of the second case. It has been considered that this biomechanical subsystem consists of 3 anatomicalelements: the head, the cervical region and the rest of the spine (considered as being a single element consisting of the thoracic region, lumbar region, sacral region and coccygeal region).The forces which stress the head and spine during normal movements or when activities in the workplace are performed make biomechanical modeling different. Therefore, the movement of the subsystem was analyzed in the sagittal plane taking into consideration joints of cylindroid type, and the subsystem as a triple inverted pendulum.The main purpose of this model was to obtain the differential equations of motion of the mechanical subsystem considered to be in the matrix-analytical form.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125705466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. F. Ionescu, D. Guglea, C. Georgescu, P. Alexandru, L. Deleanu
This paper presents the influence of load and sliding velocity on several tribological parameters like friction coefficient and wear rate of the wear scar diameter of the balls used in a four-ball test, when using rapeseed oil as lubricants. The test parameters for were: loading force - 100 N, 200 N and 300 N (± 5%), sliding speed of 0.38 m/s, 0.53 m/s and 0.69 m/s, corresponding to the spindle speeds of the four-ball machine 1000 rpm, 1400 rpm and 1800 rpm (± 6 rpm), respectively, test time - 60 minutes (± 1%). The test balls are lime polished, made of chrome alloyed steel balls (EN31), having 12.7±0.0005 mm in diameter, with 805 N/mm2 hardness VHN, as delivered by SKF. The sample oil volume required for a test was 8 ml ± 1 ml. A general view of the results on friction coefficient reveals that this vegetal oil could be used in application with mild regime as concerning the load and speed.
{"title":"TRIBOLOGICAL BEHAVIOR OF COARSE RAPESEED OIL TESTED ON FOUR BALL TESTER","authors":"T. F. Ionescu, D. Guglea, C. Georgescu, P. Alexandru, L. Deleanu","doi":"10.35219/mtd.2021.1.01","DOIUrl":"https://doi.org/10.35219/mtd.2021.1.01","url":null,"abstract":"This paper presents the influence of load and sliding velocity on several tribological parameters like friction coefficient and wear rate of the wear scar diameter of the balls used in a four-ball test, when using rapeseed oil as lubricants. The test parameters for were: loading force - 100 N, 200 N and 300 N (± 5%), sliding speed of 0.38 m/s, 0.53 m/s and 0.69 m/s, corresponding to the spindle speeds of the four-ball machine 1000 rpm, 1400 rpm and 1800 rpm (± 6 rpm), respectively, test time - 60 minutes (± 1%). The test balls are lime polished, made of chrome alloyed steel balls (EN31), having 12.7±0.0005 mm in diameter, with 805 N/mm2 hardness VHN, as delivered by SKF. The sample oil volume required for a test was 8 ml ± 1 ml. A general view of the results on friction coefficient reveals that this vegetal oil could be used in application with mild regime as concerning the load and speed.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129790202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Energy production based on fossil fuels is the main reason for global warming. Many countries have begun switching fossil fuels with renewable energies, reducing the effects of climate change. A tremendous potential in future energy needs plays the Marine Renewable Energies (MRE). The MRE industry should take into consideration the potential environmental effects and if it poses any risks to marine animals, surrounding habitats or ecosystem processes. This research provides some insights regarding the MRE development and points out the potential environmental effects of implementing them and finally, draws some lines regarding the ecological effects of the MRE extraction from the Black Sea.
{"title":"AN EVALUATION OF THE POTENTIAL IMPACT OF EXTRACTING MARINE RENEWABLE ENERGY IN THE COASTAL ENVIRONMENT OF THE BLACK SEA","authors":"Laura Zburlea, E. Rusu","doi":"10.35219/mtd.2021.1.02","DOIUrl":"https://doi.org/10.35219/mtd.2021.1.02","url":null,"abstract":"Energy production based on fossil fuels is the main reason for global warming. Many countries have begun switching fossil fuels with renewable energies, reducing the effects of climate change. A tremendous potential in future energy needs plays the Marine Renewable Energies (MRE). The MRE industry should take into consideration the potential environmental effects and if it poses any risks to marine animals, surrounding habitats or ecosystem processes. This research provides some insights regarding the MRE development and points out the potential environmental effects of implementing them and finally, draws some lines regarding the ecological effects of the MRE extraction from the Black Sea.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"429 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133939046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For this paper, the authors studied the behavior of castor oil, when it accidentally reaches a hot surface. Thus, the lowest temperature at which castor oil ignited at least once in three tests and the highest temperature at which castor oil did not ignite in three tests were determined. To determine as accurately as possible these two temperatures, a total of 29 tests were performed. The procedure complies with ISO 20823:2018 Petroleum and related products -Determination of the flammability characteristics of fluids in contact with hot surfaces - Manifold ignition test.
{"title":"FLAMMABILITY TESTS ON HOT SURFACE FOR CASTOR OIL","authors":"L. Șolea, L. Deleanu","doi":"10.35219/MTD.2020.4.04","DOIUrl":"https://doi.org/10.35219/MTD.2020.4.04","url":null,"abstract":"For this paper, the authors studied the behavior of castor oil, when it accidentally reaches a hot surface. Thus, the lowest temperature at which castor oil ignited at least once in three tests and the highest temperature at which castor oil did not ignite in three tests were determined. To determine as accurately as possible these two temperatures, a total of 29 tests were performed. The procedure complies with ISO 20823:2018 Petroleum and related products -Determination of the flammability characteristics of fluids in contact with hot surfaces - Manifold ignition test.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127344922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"EFFECTS OF LOW-FREQUENCY NOISE ON CREWS OF RIVER VESSELS ON THE DANUBE","authors":"L. Rusu, E. Rusu, Dunărea de Jos","doi":"10.35219/mtd.2019.3.02","DOIUrl":"https://doi.org/10.35219/mtd.2019.3.02","url":null,"abstract":"","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124768898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The recent theory of the coastal risk index (C@R) represents a theory, whose approach is based on a series of indicators targeting natural and anthropic processes. These indicators aim to assess the risk of coastal areas exposed to natural hazards (sea level rise, storms, floods etc.). Also, the coastal risk index assesses the degradation of coastal resources and the factors that favor this phenomenon. The C@R index was developed with a special emphasis on coastal and environmental risks and is based on the World Risk Index concept [1]. At the level of the Romanian coastal area, a master plan for protecting the coastal area has been adopted since 2011, a document that has generated several shore protection solutions. During 2014-2017, hard type protection works were carried out in the areas considered the most vulnerable in terms of coastal erosion [2]. The present paper aims to analyze the introduction of a modern risk assessment system by applying the C@R index, at the level of the Romanian coastal area. The purpose of this tool is to help and inform decision makers at all levels about the existing risks, so that they can find solutions to reduce these risks.
{"title":"INTRODUCTION THE COASTAL AT RISK INDEX IN THE ROMANIAN BLACK SEA AREA","authors":"Anton Catalin, E. Rusu, Dunărea de Jos","doi":"10.35219/mtd.2019.3.01","DOIUrl":"https://doi.org/10.35219/mtd.2019.3.01","url":null,"abstract":"The recent theory of the coastal risk index (C@R) represents a theory, whose approach is based on a series of indicators targeting natural and anthropic processes. These indicators aim to assess the risk of coastal areas exposed to natural hazards (sea level rise, storms, floods etc.). Also, the coastal risk index assesses the degradation of coastal resources and the factors that favor this phenomenon. The C@R index was developed with a special emphasis on coastal and environmental risks and is based on the World Risk Index concept [1]. At the level of the Romanian coastal area, a master plan for protecting the coastal area has been adopted since 2011, a document that has generated several shore protection solutions. During 2014-2017, hard type protection works were carried out in the areas considered the most vulnerable in terms of coastal erosion [2]. The present paper aims to analyze the introduction of a modern risk assessment system by applying the C@R index, at the level of the Romanian coastal area. The purpose of this tool is to help and inform decision makers at all levels about the existing risks, so that they can find solutions to reduce these risks.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128024957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IonescuTraian Florian Ionescu, L. Șolea, D. Guglea, C. Georgescu, L. Deleanu, Dunărea de Jos
This paper presents a tribological characterization in seizure regime for two lubricants (rapeseed oil and rapeseed oil additivated with 1%wt TiO2). Tests were done on a four-ball tester, in the load range at the tester shaft 500...900 N, in step of 50 N, for 60 seconds and with a rotational speed of 1400 rpm (equivalent to a sliding speed of 0.53 m/s). There were discussed the average value of friction coefficient, the wear scar diameter (WSD), the flash temperature parameter and several texture 3D parameters. Till 600 N, the influence of additivation is not obvious, the friction coefficient is lower for the neat oil, WSD is similar, but after this load, the slope for WSD is smaller for the additivated lubricant and for 900 N, this parameter is also smaller. Sa seems to be quite insensitive to the load increase, but other parameters, like St has a significant increase, meaning two processes: additive is pressed on the surface and developed high local peaks or/and the adhesive and abrasive wear is more intense. FTP is almost the same at 900 N, but the additive makes this parameter to evolve with a plateau with low slope, meaning the additivated lubricant has a better behavior under high loads. .
{"title":"EVALUATING SEIZURE ON FOUR BALL TESTER FOR RAPESEED OIL","authors":"IonescuTraian Florian Ionescu, L. Șolea, D. Guglea, C. Georgescu, L. Deleanu, Dunărea de Jos","doi":"10.35219/mtd.2019.3.03","DOIUrl":"https://doi.org/10.35219/mtd.2019.3.03","url":null,"abstract":"This paper presents a tribological characterization in seizure regime for two lubricants (rapeseed oil and rapeseed oil additivated with 1%wt TiO2). Tests were done on a four-ball tester, in the load range at the tester shaft 500...900 N, in step of 50 N, for 60 seconds and with a rotational speed of 1400 rpm (equivalent to a sliding speed of 0.53 m/s). There were discussed the average value of friction coefficient, the wear scar diameter (WSD), the flash temperature parameter and several texture 3D parameters. Till 600 N, the influence of additivation is not obvious, the friction coefficient is lower for the neat oil, WSD is similar, but after this load, the slope for WSD is smaller for the additivated lubricant and for 900 N, this parameter is also smaller. Sa seems to be quite insensitive to the load increase, but other parameters, like St has a significant increase, meaning two processes: additive is pressed on the surface and developed high local peaks or/and the adhesive and abrasive wear is more intense. FTP is almost the same at 900 N, but the additive makes this parameter to evolve with a plateau with low slope, meaning the additivated lubricant has a better behavior under high loads. .","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114991646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most of the global trade is carried by sea as the Earth surface is covered more than ¾ with water. For commercial purposes, the size of ships has continuously increased; thus, the space for cargo and passengers became more generous. Though, this leads to higher risks: reduced maneuverability, especially in narrow or confined waters, more costly intervention in case of an accident and consistent relief actions. When naval accidents affect the property, human life and environment are severely affected. To reduce the risk of accidents or curb their effects when produced, all stakeholders involved in shipping must obey the provisions of international regulations related to the safety of ships operations, collision avoidance, pollution prevention, and so on. Along with enforcing international regulations in the field, effective management of intervention in the case of an accident has to be adopted. This paper presents the influence of environmental factors in the western Black Sea basin on naval accidents, along with considerations related to the system of intervention in the case of distress situations or accident in the Romanian sector of the Black Sea.
{"title":"BLACK SEA NAVAL ACCIDENTS – INTERVENTION MANAGEMENT","authors":"V. Novac, E. Rusu, G. Stăvărache, Dunărea de Jos","doi":"10.35219/mtd.2019.2.02","DOIUrl":"https://doi.org/10.35219/mtd.2019.2.02","url":null,"abstract":"Most of the global trade is carried by sea as the Earth surface is covered more than ¾ with water. For commercial purposes, the size of ships has continuously increased; thus, the space for cargo and passengers became more generous. Though, this leads to higher risks: reduced maneuverability, especially in narrow or confined waters, more costly intervention in case of an accident and consistent relief actions. When naval accidents affect the property, human life and environment are severely affected. To reduce the risk of accidents or curb their effects when produced, all stakeholders involved in shipping must obey the provisions of international regulations related to the safety of ships operations, collision avoidance, pollution prevention, and so on. Along with enforcing international regulations in the field, effective management of intervention in the case of an accident has to be adopted. This paper presents the influence of environmental factors in the western Black Sea basin on naval accidents, along with considerations related to the system of intervention in the case of distress situations or accident in the Romanian sector of the Black Sea.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124306767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper aims to investigate the wind conditions at 150 m above the surface, using the extreme value theory, a branch of statistics dealing with the extreme deviations from the median of probability distributions, and the physical model of the MERRA 2 global reanalysis data set in the nearby area of Cobadin Commune, Constanta County, Romania. The insights of the wind characteristics and the knowledge of the extreme values of the wind speed can be useful, not just for the designers, in the rational assessment of the structural safety of wind turbines, but also those evaluating the insured losses.
{"title":"PRELIMINARY ASSESSMENT OF WIND CONDITIONS IN CONSTANTA COUNTY BASED ON REANALYSIS SERIES","authors":"Emilian Boboc","doi":"10.35219/mtd.2019.2.03","DOIUrl":"https://doi.org/10.35219/mtd.2019.2.03","url":null,"abstract":"The paper aims to investigate the wind conditions at 150 m above the surface, using the extreme value theory, a branch of statistics dealing with the extreme deviations from the median of probability distributions, and the physical model of the MERRA 2 global reanalysis data set in the nearby area of Cobadin Commune, Constanta County, Romania. The insights of the wind characteristics and the knowledge of the extreme values of the wind speed can be useful, not just for the designers, in the rational assessment of the structural safety of wind turbines, but also those evaluating the insured losses.","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132963478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cristina Călin, Calorgal S.A. Galati, E. Rusu, Ș. Dragomir
{"title":"RISK ANALYSIS ON THE HEAT PUMP SYSTEM TO USE FOR BUILDING HEATING, IN URBAN AREA","authors":"Cristina Călin, Calorgal S.A. Galati, E. Rusu, Ș. Dragomir","doi":"10.35219/mtd.2019.2.01","DOIUrl":"https://doi.org/10.35219/mtd.2019.2.01","url":null,"abstract":"","PeriodicalId":125331,"journal":{"name":"Mechanical Testing and Diagnosis","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133607727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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