Abstract Inertial vibrating screens operating in resonance and post-resonance mode represent a class of screens that present a series of advantages: simple construction and maintenance, high flow rates, low energy consumption, low level of vibrations transmitted to the building in which they are located, high screening efficiency. Due to these advantages, they tend to replace all other types of screens. However, these cisterns are very sensitive to variations in the supply flow, therefore they must be equipped with electronic control devices and automatic control of the supply flow with mineral aggregates. The present paper presents a numerical simulation of the variation of the vibration amplitudes for different values of the material on the screen using the professional calculation program MATHCAD 14.
{"title":"Mathematical Modeling and Numerical Simulation of the Functioning of Inertial Vibrating Screens in Resonant and Post-Resonant Regime","authors":"Cornel Marin, Daniela Mariutei","doi":"10.2478/bsmm-2022-0019","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0019","url":null,"abstract":"Abstract Inertial vibrating screens operating in resonance and post-resonance mode represent a class of screens that present a series of advantages: simple construction and maintenance, high flow rates, low energy consumption, low level of vibrations transmitted to the building in which they are located, high screening efficiency. Due to these advantages, they tend to replace all other types of screens. However, these cisterns are very sensitive to variations in the supply flow, therefore they must be equipped with electronic control devices and automatic control of the supply flow with mineral aggregates. The present paper presents a numerical simulation of the variation of the vibration amplitudes for different values of the material on the screen using the professional calculation program MATHCAD 14.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"42 1","pages":"47 - 52"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82222730","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 aim of the paper consists in the study of three Romanian types of marble (Ruschita, Albesti, Carrara) with different compositions in different temperature conditions, for different periods of time. The three samples were exposed to two different types of treatments: 25 cycles of freeze-thaw (according to SR EN 12371) and 3 cycles of exposure to high temperatures (400 °C for 1 hour). Following the freeze-thaw cycles, small differences in chromatic parameters could be observed (∆E = 2.2 for Carrara Italia marble and ∆E = 7.2 for Rușchița pink marble). The freezing coefficient for all samples is low (0.016% - 0.029%). Following exposure to high temperature treatment, the samples show large differences in chromatic parameters (∆E = 43.47 for Albesti marble) and significant changes in gloss. The surface of the samples showed cracks and microcracks. Based on the results of this study, the following conclusions can be drawn: Thermal cycles can cause the mechanical disintegration of the outer part of the marble, starting from the discontinuities contained in the rock and between the faces between the different minerals that form the stone. Exposure to high temperatures will result in a loss of adhesion between the surface grains on the sample surface. The degradation processes have been investigated.
{"title":"Evaluation of Marble Alteration Processes","authors":"I. Zăuleț, R. Ion, C. Rizescu","doi":"10.2478/bsmm-2022-0015","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0015","url":null,"abstract":"Abstract The aim of the paper consists in the study of three Romanian types of marble (Ruschita, Albesti, Carrara) with different compositions in different temperature conditions, for different periods of time. The three samples were exposed to two different types of treatments: 25 cycles of freeze-thaw (according to SR EN 12371) and 3 cycles of exposure to high temperatures (400 °C for 1 hour). Following the freeze-thaw cycles, small differences in chromatic parameters could be observed (∆E = 2.2 for Carrara Italia marble and ∆E = 7.2 for Rușchița pink marble). The freezing coefficient for all samples is low (0.016% - 0.029%). Following exposure to high temperature treatment, the samples show large differences in chromatic parameters (∆E = 43.47 for Albesti marble) and significant changes in gloss. The surface of the samples showed cracks and microcracks. Based on the results of this study, the following conclusions can be drawn: Thermal cycles can cause the mechanical disintegration of the outer part of the marble, starting from the discontinuities contained in the rock and between the faces between the different minerals that form the stone. Exposure to high temperatures will result in a loss of adhesion between the surface grains on the sample surface. The degradation processes have been investigated.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"56 1","pages":"29 - 32"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86789769","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":"Editorial: (Nano)Science and (Nano)Materials in Materials Engineering and Mechanics","authors":"R. Ion, V. Bratu, Cornel Marin, F. Popa","doi":"10.2478/bsmm-2022-0011","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0011","url":null,"abstract":"","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"87 1","pages":"7 - 7"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91353029","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 aim of the paper was to develop methods for obtaining environmentally friendly nanomaterials. The plant extracts used in this paper were characterized by spectroscopic methods (UV-Vis, FTIR and Raman). In this regard, it was used vegetal material at the optimal time and in the period of maximum maturity of the plant, from the geographical area of Dâmbovița County, and being processed in fresh / dry status. The nanomaterials formed with the help of these plant extracts (Ag) have also been characterized by various analytical techniques (UV-Vis, FTIR, Raman) analysis. The bioactive compounds existing in plant materials are responsible for the bio reduction of silver (Ag+ to Ag0) ions, as well as for the stabilization of silver nanoparticles.
{"title":"Synthesis of Silver Nanoparticles using Hydroalcoholic Extract of Prunus Mahaleb (Mahaleb Cherry) and Malus Purpurea (Blutapfel)","authors":"N. Stirbescu, R. Stirbescu, R. Olteanu, R. Ion","doi":"10.2478/bsmm-2022-0017","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0017","url":null,"abstract":"Abstract The aim of the paper was to develop methods for obtaining environmentally friendly nanomaterials. The plant extracts used in this paper were characterized by spectroscopic methods (UV-Vis, FTIR and Raman). In this regard, it was used vegetal material at the optimal time and in the period of maximum maturity of the plant, from the geographical area of Dâmbovița County, and being processed in fresh / dry status. The nanomaterials formed with the help of these plant extracts (Ag) have also been characterized by various analytical techniques (UV-Vis, FTIR, Raman) analysis. The bioactive compounds existing in plant materials are responsible for the bio reduction of silver (Ag+ to Ag0) ions, as well as for the stabilization of silver nanoparticles.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"36 1","pages":"39 - 42"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86689569","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, F. Anghelina, M. Enescu, A. Poinescu, A. Catangiu
Abstract The paper presents an overview of (i) the different polluting materials, classified according to their (bio)degradability, (ii) the sources of pollution (iii) the general effects of pollution on natural resources and on the economy and people’s health. The paper also summarizes directions/solutions to eliminate these effects, including “eco” technologies, and their effectiveness on environmental conservation and regional and global ecosystem protection, in the context of a clean and sustainable environment, in accordance with the 2030 Agenda for Sustainable Development.
{"title":"Polluting Materials, the Effects of Industrial Pollution and Directions/Solutions to Eliminate these Effects","authors":"I. Popescu, F. Anghelina, M. Enescu, A. Poinescu, A. Catangiu","doi":"10.2478/bsmm-2022-0014","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0014","url":null,"abstract":"Abstract The paper presents an overview of (i) the different polluting materials, classified according to their (bio)degradability, (ii) the sources of pollution (iii) the general effects of pollution on natural resources and on the economy and people’s health. The paper also summarizes directions/solutions to eliminate these effects, including “eco” technologies, and their effectiveness on environmental conservation and regional and global ecosystem protection, in the context of a clean and sustainable environment, in accordance with the 2030 Agenda for Sustainable Development.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"31 1","pages":"23 - 28"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87915233","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}
R. Grigorescu, L. Iancu, R. Ion, M. David, E. Alexandrescu, M. Ghiurea, R. Stirbescu
Abstract The aim of the paper consist in the synthesis of double substituted carbonated hydroxyapatite using Zn2+ and Mg2+ ions in comparison with the previous obtained Sr-Zn-CHAp. Fourier transform infrared spectroscopy, X-ray diffraction, environmental scanning electron microscope (ESEM) coupled with EDS is used to highlight the presence of the metallic ions into the apatite structure. Both inorganic compounds are tested as consolidants for two types of fir wood, young and 30-years old samples. The consolidation efficiency is demonstrated by colorimetric analysis, mechanical tests and the specific methods for water absorption behavior. Stronger specimens, especially of young wood, with no significant color differences, more hygroscopic and with higher hysteresis index result after treatment. In conclusion, carbonated hydroxyapatite double substituted with zinc, magnesium and strontium ions can be used in wood preservation-conservation techniques.
{"title":"Double-Substituted Carbonated Hydroxyapatites for Fir Wood Treatment","authors":"R. Grigorescu, L. Iancu, R. Ion, M. David, E. Alexandrescu, M. Ghiurea, R. Stirbescu","doi":"10.2478/bsmm-2022-0013","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0013","url":null,"abstract":"Abstract The aim of the paper consist in the synthesis of double substituted carbonated hydroxyapatite using Zn2+ and Mg2+ ions in comparison with the previous obtained Sr-Zn-CHAp. Fourier transform infrared spectroscopy, X-ray diffraction, environmental scanning electron microscope (ESEM) coupled with EDS is used to highlight the presence of the metallic ions into the apatite structure. Both inorganic compounds are tested as consolidants for two types of fir wood, young and 30-years old samples. The consolidation efficiency is demonstrated by colorimetric analysis, mechanical tests and the specific methods for water absorption behavior. Stronger specimens, especially of young wood, with no significant color differences, more hygroscopic and with higher hysteresis index result after treatment. In conclusion, carbonated hydroxyapatite double substituted with zinc, magnesium and strontium ions can be used in wood preservation-conservation techniques.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"15 1","pages":"15 - 22"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88544961","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 On base of obtained results in working [1], in a certain case one should take account the lineal chamfering of ribs upon the neutral fiber position and of the circular and plane plate bending rigiditybwith radial ribs. The illustration of the theoretical resultss is achieved on a given case.
{"title":"Regarding at the Circular Plates Rigidity with Radial Ribs, Neglecting the Welding Seams Influence. Ribs with Constant Thickness and Lineal Variable Heighness on Length, Placed Just on a Face","authors":"C. Popa, V. Anghelina, V. Despa","doi":"10.2478/bsmm-2022-0020","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0020","url":null,"abstract":"Abstract On base of obtained results in working [1], in a certain case one should take account the lineal chamfering of ribs upon the neutral fiber position and of the circular and plane plate bending rigiditybwith radial ribs. The illustration of the theoretical resultss is achieved on a given case.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"110 1","pages":"53 - 56"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78005744","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 This scientific work continues the ideas and research from a previous work and presents the progressive conceptions of the future from Mechatronics to Cyber-Mechatronics and from Mechatronics Systems Cyber-Mechatronics Systems, as they are presented at the moment. It also tries to mention the scientific and technological advances in the above mentioned fields, the new and complex innovative concepts of science and Mechatronics and Cyber-Mechatronics. Anticipating the future, the power and flexibility that will flow from the ability to “program” the world around us should influence every aspect of the human experience.
{"title":"Progressive Conceptions of the Future in Cyber-Mix Mechatronics Industry and Claytronics Engineering (II)","authors":"V. Despa, F. Badea, S. Badea","doi":"10.2478/bsmm-2022-0018","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0018","url":null,"abstract":"Abstract This scientific work continues the ideas and research from a previous work and presents the progressive conceptions of the future from Mechatronics to Cyber-Mechatronics and from Mechatronics Systems Cyber-Mechatronics Systems, as they are presented at the moment. It also tries to mention the scientific and technological advances in the above mentioned fields, the new and complex innovative concepts of science and Mechatronics and Cyber-Mechatronics. Anticipating the future, the power and flexibility that will flow from the ability to “program” the world around us should influence every aspect of the human experience.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"36 1","pages":"43 - 46"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75916820","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}
L. Iancu, R. Grigorescu, R. Ion, M. David, Sofia Slamnoiu-Teodorescu
Abstract The aim of the paper consists in assessing the protection of fir wood samples against UV degradation by using polyacrylates and titanium dioxide as absorber. The irradiation was achieved for 648 hours, considered as about 2 years of weathering. Colorimetric, water absorption, and mechanical investigations were performed on samples before and after irradiation. The structural changes were evidenced by FTIR spectroscopy. Small changes in color for coated wood samples are observed after maximum 648 h of UV treatment, with the best results obtained for the specimen covered with Paraloid B72-TiO2. Higher compressive strengths were observed for the polymer-TiO2 coatings, in correlation with a smaller water absorption capacity of the studied samples. FTIR revealed shifted peaks with increased intensities as proof of structural changes produced by irradiation of lignin and polyacrylates. The results highlight that Paraloid B72 and Paraloid B67 mixed with TiO2 can be used as efficient UV protective coatings for fir wood.
{"title":"The Effect of UV Irradiation on the Stability of Coated Fir Wood Samples","authors":"L. Iancu, R. Grigorescu, R. Ion, M. David, Sofia Slamnoiu-Teodorescu","doi":"10.2478/bsmm-2022-0012","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0012","url":null,"abstract":"Abstract The aim of the paper consists in assessing the protection of fir wood samples against UV degradation by using polyacrylates and titanium dioxide as absorber. The irradiation was achieved for 648 hours, considered as about 2 years of weathering. Colorimetric, water absorption, and mechanical investigations were performed on samples before and after irradiation. The structural changes were evidenced by FTIR spectroscopy. Small changes in color for coated wood samples are observed after maximum 648 h of UV treatment, with the best results obtained for the specimen covered with Paraloid B72-TiO2. Higher compressive strengths were observed for the polymer-TiO2 coatings, in correlation with a smaller water absorption capacity of the studied samples. FTIR revealed shifted peaks with increased intensities as proof of structural changes produced by irradiation of lignin and polyacrylates. The results highlight that Paraloid B72 and Paraloid B67 mixed with TiO2 can be used as efficient UV protective coatings for fir wood.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"17 1","pages":"8 - 14"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89325019","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 In order to improve the anticorrosion protection properties, polypyrrole thin films were deposited on silicon steel plates. The anticorrosive protection effect of the polypriol coating was evaluated by electrochemical measurements in two different aqueous solutions of potassium chloride and hydrochloric acid. Polypyrrole-coated silicon steel plates were immersed for one and seven days, respectively. The obtained results show that the thin layer of polypyrrole ensures effective protection of silicon steel against corrosion, especially in aqueous potassium chloride solution.
{"title":"Anticorrosive Polymeric Coatings","authors":"D. Brezoi","doi":"10.2478/bsmm-2022-0016","DOIUrl":"https://doi.org/10.2478/bsmm-2022-0016","url":null,"abstract":"Abstract In order to improve the anticorrosion protection properties, polypyrrole thin films were deposited on silicon steel plates. The anticorrosive protection effect of the polypriol coating was evaluated by electrochemical measurements in two different aqueous solutions of potassium chloride and hydrochloric acid. Polypyrrole-coated silicon steel plates were immersed for one and seven days, respectively. The obtained results show that the thin layer of polypyrrole ensures effective protection of silicon steel against corrosion, especially in aqueous potassium chloride solution.","PeriodicalId":30754,"journal":{"name":"Scientific Bulletin of Valahia University Materials and Mechanics","volume":"17 1","pages":"33 - 38"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87891569","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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