Abstract In recent decades, the interest of researchers and engineers in obtaining competitive materials is increasing. The effects of friction on materials are quite difficult to explain due to the micro and macroscopic interactions of the surfaces of the friction couple, which slide over each other. The friction and wear behavior of sliding surfaces can be considered important design criteria. The fact that for a kinematic coupling with sliding motion, a material with a higher hardness is used in most cases in combination with a material with a lower hardness, there is the possibility of abrasion wear and local plastic deformations. The paper proposes in analytical model for calculating the coefficient of friction when a rigid conical penetrator passes over a flat surface with a lower hardness and establishing the response mode of the material of the flat surface. The penetration method corresponds to the deformation produced by asperities in practice. The proposed theoretical model will be experimentally validated on a tribological stand made in this sense. Comparing the experimental results with the theoretical ones confirms the veracity of the model and also corresponds to many of the experimental results obtained in specialized works.
{"title":"Theoretical and Experimental Research on the Evolution of the Friction Coefficient in Different Lubrication Conditions in the Case of Friction Couples with Sliding Motion","authors":"I. Petre, E. Stoian, M. Enescu","doi":"10.2478/bsmm-2023-0009","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0009","url":null,"abstract":"Abstract In recent decades, the interest of researchers and engineers in obtaining competitive materials is increasing. The effects of friction on materials are quite difficult to explain due to the micro and macroscopic interactions of the surfaces of the friction couple, which slide over each other. The friction and wear behavior of sliding surfaces can be considered important design criteria. The fact that for a kinematic coupling with sliding motion, a material with a higher hardness is used in most cases in combination with a material with a lower hardness, there is the possibility of abrasion wear and local plastic deformations. The paper proposes in analytical model for calculating the coefficient of friction when a rigid conical penetrator passes over a flat surface with a lower hardness and establishing the response mode of the material of the flat surface. The penetration method corresponds to the deformation produced by asperities in practice. The proposed theoretical model will be experimentally validated on a tribological stand made in this sense. Comparing the experimental results with the theoretical ones confirms the veracity of the model and also corresponds to many of the experimental results obtained in specialized works.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"51 1","pages":"57 - 60"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84621172","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}
Georgiana Patulea Paraschiv, R. Ion, Sofia Slamnoiuteodorescu, A. Gheboianu
Abstract The aim of the paper is a spectral study of a mural fresco from Serbesti wooden church, Dambovita county, partially painted, a historical monument from 1828 (or 1804 after some other documents). Spectral techniques as X-ray Fluorescence wavelengths dispersive (WDXRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) or Raman spectroscopy, have been used in order to highlight the presence of the degradation processes. Also, the chromatic parameters have been used as additional data in order to observe the discoloring aspect of these mural fresco.
{"title":"Spectral Study of the Mural Painting Degradation in Wooden Churches","authors":"Georgiana Patulea Paraschiv, R. Ion, Sofia Slamnoiuteodorescu, A. Gheboianu","doi":"10.2478/bsmm-2023-0004","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0004","url":null,"abstract":"Abstract The aim of the paper is a spectral study of a mural fresco from Serbesti wooden church, Dambovita county, partially painted, a historical monument from 1828 (or 1804 after some other documents). Spectral techniques as X-ray Fluorescence wavelengths dispersive (WDXRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) or Raman spectroscopy, have been used in order to highlight the presence of the degradation processes. Also, the chromatic parameters have been used as additional data in order to observe the discoloring aspect of these mural fresco.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"29 1","pages":"25 - 30"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84659265","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}
I. Popescu, A. Poinescu, D. Ungureanu, Adrian Picu
Abstract In this brief review, porous and non-porous biomaterials used as scaffolds in regenerative medicine and tissue engineering and new innovative techniques to obtain biomaterials were discussed. Various methods have been presented to obtain advanced materials used as scaffolds, such as (i) 3D printed biomineral composites obtained with bacteria-loaded ink (bactoInk), (ii) the use of vegetable waste, such as rice husks, parsley, spinach or cocoa in the development of bioplastics, (iii) the use of natural biological materials of animal origin (such as bovine bones, corals, snail shells or eggshells) from waste, or (iv) the creation of new biomaterials that can reduce or combat the infection of scaffolds after implantation.
{"title":"Novel Developments in Advanced Materials Fields: Porous and Non-Porous Biomaterials Used in Regenerative Medicine and Tissue Engineering","authors":"I. Popescu, A. Poinescu, D. Ungureanu, Adrian Picu","doi":"10.2478/bsmm-2023-0007","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0007","url":null,"abstract":"Abstract In this brief review, porous and non-porous biomaterials used as scaffolds in regenerative medicine and tissue engineering and new innovative techniques to obtain biomaterials were discussed. Various methods have been presented to obtain advanced materials used as scaffolds, such as (i) 3D printed biomineral composites obtained with bacteria-loaded ink (bactoInk), (ii) the use of vegetable waste, such as rice husks, parsley, spinach or cocoa in the development of bioplastics, (iii) the use of natural biological materials of animal origin (such as bovine bones, corals, snail shells or eggshells) from waste, or (iv) the creation of new biomaterials that can reduce or combat the infection of scaffolds after implantation.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"1 1","pages":"42 - 52"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86901717","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}
Abstract The paper presents an experimental device designed to measure the bending temperature of deflection under load, one of the most important thermomechanical characteristics of polymeric materials. The device allows the application of a prescribed load which has the effect of inducing a standard stress in a rectangular specimen through three-point bending. Subjected to this bending stress, the test specimen is heated, at a constant speed, until a prescribed deformation (deflection) is registered. The temperature and deflection are recorded continuously by a data acquisition system designed for monitoring the process and subsequent analysis of the experimental results. In order to verify the functionality of the experimental device, preliminary tests were carried out on some polymer materials that have polypropylene in their composition.
{"title":"Experimental Device with Data Acquisition for Measurement of Temperature of Deflection Under Load","authors":"A. Catangiu, D. Ungureanu, A. Poinescu, V. Gurgu","doi":"10.2478/bsmm-2023-0005","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0005","url":null,"abstract":"Abstract The paper presents an experimental device designed to measure the bending temperature of deflection under load, one of the most important thermomechanical characteristics of polymeric materials. The device allows the application of a prescribed load which has the effect of inducing a standard stress in a rectangular specimen through three-point bending. Subjected to this bending stress, the test specimen is heated, at a constant speed, until a prescribed deformation (deflection) is registered. The temperature and deflection are recorded continuously by a data acquisition system designed for monitoring the process and subsequent analysis of the experimental results. In order to verify the functionality of the experimental device, preliminary tests were carried out on some polymer materials that have polypropylene in their composition.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"128 1","pages":"31 - 37"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88717680","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}
M. Enescu, E. Stoian, Carmen Ivona Petre, C. Rusănescu
Abstract This paper presents the results of laboratory research on the influence of heat treatment on the corrosion resistance of austenitic steels (Cr-Ni, Cr, Mn, Cr-Mn-Ni), research that may extend under certain conditions and ferrites steels and semi-ferrites chrome steels.This type of intercrystalline corrosion was observed in other alloy systems due to media containing chloride ions.The experimental results consist in comparing structural changes and corrosion rate for different types of austenitic steels that were made experimental research.
{"title":"The Influence of Heat Treatments in Corrosion Resistance of Austenitic Steels","authors":"M. Enescu, E. Stoian, Carmen Ivona Petre, C. Rusănescu","doi":"10.2478/bsmm-2023-0001","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0001","url":null,"abstract":"Abstract This paper presents the results of laboratory research on the influence of heat treatment on the corrosion resistance of austenitic steels (Cr-Ni, Cr, Mn, Cr-Mn-Ni), research that may extend under certain conditions and ferrites steels and semi-ferrites chrome steels.This type of intercrystalline corrosion was observed in other alloy systems due to media containing chloride ions.The experimental results consist in comparing structural changes and corrosion rate for different types of austenitic steels that were made experimental research.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"46 1","pages":"7 - 12"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75021559","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}
A. Iordache, D. Brezoi, A. Gheboianu, Andreea Parnic, V. Parnic
Abstract The paper presents a qualitative and quantitative structural analysis of some pottery fragments belonging to the Boian culture, discovered in the archaeological site of Galatui - Movila Berzei, in a dwelling - sanctuary. Six representative pottery fragments were used. To visualize some microscopic details of the surfaces of these pottery fragments, digital optical microscopy was used. Also, for the quantitative and qualitative analysis of the crystalline structure of the powder samples taken from the surfaces, X-ray diffraction (XRD) was used. The obtained results show that the ceramic mass has a high content of quartz, accompanied by various oxide compounds from the clay used, low in calcium but rich in iron. The analyzed pottery fragments present different decorative patterns, from parallel and broken lines, to checkerboard-type patterns that denote a special leaning towards aesthetics of the communities from Galatui - Movila Berzei.
{"title":"Structural Analysis of Some Pottery Fragments from the Eneolithic Period Belonging to the Boian Culture","authors":"A. Iordache, D. Brezoi, A. Gheboianu, Andreea Parnic, V. Parnic","doi":"10.2478/bsmm-2023-0003","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0003","url":null,"abstract":"Abstract The paper presents a qualitative and quantitative structural analysis of some pottery fragments belonging to the Boian culture, discovered in the archaeological site of Galatui - Movila Berzei, in a dwelling - sanctuary. Six representative pottery fragments were used. To visualize some microscopic details of the surfaces of these pottery fragments, digital optical microscopy was used. Also, for the quantitative and qualitative analysis of the crystalline structure of the powder samples taken from the surfaces, X-ray diffraction (XRD) was used. The obtained results show that the ceramic mass has a high content of quartz, accompanied by various oxide compounds from the clay used, low in calcium but rich in iron. The analyzed pottery fragments present different decorative patterns, from parallel and broken lines, to checkerboard-type patterns that denote a special leaning towards aesthetics of the communities from Galatui - Movila Berzei.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"65 1","pages":"19 - 24"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73150605","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}
E. Stoian, M. Enescu, Camelia Ivona Petre, C. Rusănescu
Abstract This paper presents the microstructural aspects of strips cold rolled laminar and the influence of grain size on the total magnetic loss at 1T respectively 1.5T, for silicon steel strips with non-oriented grains after decarburized and annealed treatment. We find that the hardness at the head of the rolls is higher for all 5 analyzed rolls, on the other hand, for the rolls from batch II the hardness at the ends is higher than the hardness at the head. The hardness values are included in the EN standards 10106. The regression equations drawn for Rc in the raw state, as well as in the aged state, show us significant correlation coefficients very close to the value of 1, that is 0.98 for Rc raw and 0.97 for Rc aged.The regression equations plotted for Rm in the raw state for the batch of bands analyzed, as well as in the aged state, show us significant correlation coefficients very close to the value of 1, i.e. 0.91 for Rm raw and o.98 for Rm aged.
{"title":"Analysis of the Mechanical Properties of Electrical Steel","authors":"E. Stoian, M. Enescu, Camelia Ivona Petre, C. Rusănescu","doi":"10.2478/bsmm-2023-0006","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0006","url":null,"abstract":"Abstract This paper presents the microstructural aspects of strips cold rolled laminar and the influence of grain size on the total magnetic loss at 1T respectively 1.5T, for silicon steel strips with non-oriented grains after decarburized and annealed treatment. We find that the hardness at the head of the rolls is higher for all 5 analyzed rolls, on the other hand, for the rolls from batch II the hardness at the ends is higher than the hardness at the head. The hardness values are included in the EN standards 10106. The regression equations drawn for Rc in the raw state, as well as in the aged state, show us significant correlation coefficients very close to the value of 1, that is 0.98 for Rc raw and 0.97 for Rc aged.The regression equations plotted for Rm in the raw state for the batch of bands analyzed, as well as in the aged state, show us significant correlation coefficients very close to the value of 1, i.e. 0.91 for Rm raw and o.98 for Rm aged.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"11 1","pages":"38 - 41"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86583500","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}
D. Ungureanu, D. Avram, Nicolae Angelescu, A. Catangiu, I. Popescu, V. Anghelina
Abstract In this paper was synthesized a bioceramic material based on calcium and phosphorus. Also, the effect of synthesis parameters on the structure and properties of the obtained powders has been studied. In this sense, the stirring speed and the aging time of the precipitates, in the case of some hydroxyapatite powders, are studied. The results show products with the desired characteristics, in terms of structure and composition of analyzed powders.
{"title":"The Effect of Some Process Parameters in the Synthesis of Ceramics Based on Calcium and Phosphorus","authors":"D. Ungureanu, D. Avram, Nicolae Angelescu, A. Catangiu, I. Popescu, V. Anghelina","doi":"10.2478/bsmm-2023-0008","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0008","url":null,"abstract":"Abstract In this paper was synthesized a bioceramic material based on calcium and phosphorus. Also, the effect of synthesis parameters on the structure and properties of the obtained powders has been studied. In this sense, the stirring speed and the aging time of the precipitates, in the case of some hydroxyapatite powders, are studied. The results show products with the desired characteristics, in terms of structure and composition of analyzed powders.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"16 1","pages":"53 - 56"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79179108","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}
Abstract The method of transporting cement with the help of an air jet through pipes is very practical and reliable. However, improper dimensioning of the constructive and functional parameters can lead to improper functioning, to cement agglomerations in certain areas of the route configuration. In order to be able to know the problem areas and geometries, in this paper a comparative, analytical and virtual study of cement transport through a pipeline route, known as geometry and dimensions, was made. Analytical calculation showed that a floating speed of cement particles of 23.45 m/s, with an air flow rate of 0.155 m3/s, is needed to be able to transport a quantity of 40 t/h (11.11 kg/s) of cement. The virtual study done in Flow Simulation showed the behavior of cement particles during transport. The virtual behavior is similar to the real one, with cement particles tending to settle in bends and on long stretches of horizontal pipes. The behavior of the air-cement mixture in the separation cyclone is well exemplified by the virtual simulation. The separation of those two components is well represented and conforms to the real phenomenon.
{"title":"Comparative, Analytical and Virtual Study of the Flow Parameters of the Bearing Cement-Air Mixture, in a Pipeline Route","authors":"A. Negrea, I. Popa, V. Despa","doi":"10.2478/bsmm-2023-0010","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0010","url":null,"abstract":"Abstract The method of transporting cement with the help of an air jet through pipes is very practical and reliable. However, improper dimensioning of the constructive and functional parameters can lead to improper functioning, to cement agglomerations in certain areas of the route configuration. In order to be able to know the problem areas and geometries, in this paper a comparative, analytical and virtual study of cement transport through a pipeline route, known as geometry and dimensions, was made. Analytical calculation showed that a floating speed of cement particles of 23.45 m/s, with an air flow rate of 0.155 m3/s, is needed to be able to transport a quantity of 40 t/h (11.11 kg/s) of cement. The virtual study done in Flow Simulation showed the behavior of cement particles during transport. The virtual behavior is similar to the real one, with cement particles tending to settle in bends and on long stretches of horizontal pipes. The behavior of the air-cement mixture in the separation cyclone is well exemplified by the virtual simulation. The separation of those two components is well represented and conforms to the real phenomenon.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"39 1","pages":"61 - 67"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73146493","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}
S. M. Hasan, Souvik Ghatak, Asif Azad, Avijit Mallik
Abstract These days, noise pollution is a major issue that affects the environment. The high amount of noise present in the industries has adverse impact on the workers, operators and people associated in those fields. The consequences could be as hazardous as heart attack or even lifelong hearing loss. Sound absorption through barriers, mufflers are some popular fields of study. Some natural extracted materials show impressive SAC at lower and mid frequencies. Moreover, natural materials usage in this field is being popular as they emit almost zero amount of greenhouse gases and their manufacturing process requires a little amount of energy to process for ready to usage. A galvanized steel pipe as the impedance tube was chosen because it is cheaper than the impedance tube available in the market. We have tried to measure sound absorption coefficient of some combinations of different materials as an acoustic barrier material.
{"title":"Analysis and Experimental Investigation of Sound Absorbing Materials for Industrial Noise Control","authors":"S. M. Hasan, Souvik Ghatak, Asif Azad, Avijit Mallik","doi":"10.2478/bsmm-2023-0002","DOIUrl":"https://doi.org/10.2478/bsmm-2023-0002","url":null,"abstract":"Abstract These days, noise pollution is a major issue that affects the environment. The high amount of noise present in the industries has adverse impact on the workers, operators and people associated in those fields. The consequences could be as hazardous as heart attack or even lifelong hearing loss. Sound absorption through barriers, mufflers are some popular fields of study. Some natural extracted materials show impressive SAC at lower and mid frequencies. Moreover, natural materials usage in this field is being popular as they emit almost zero amount of greenhouse gases and their manufacturing process requires a little amount of energy to process for ready to usage. A galvanized steel pipe as the impedance tube was chosen because it is cheaper than the impedance tube available in the market. We have tried to measure sound absorption coefficient of some combinations of different materials as an acoustic barrier material.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"16 1","pages":"13 - 18"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87876841","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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