The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science最新文献

{"title":"Copper Corrosion in Ultrasound Cavitation Field","authors":"C. Dumitriu, A. Bărbulescu","doi":"10.35219/mms.2021.3.06","DOIUrl":"https://doi.org/10.35219/mms.2021.3.06","url":null,"abstract":"This article contains the results of the experiments concerning the mass loss of copper in seawater, in the cavitation presence. The cavitation is produced by ultrasound in an experimental setup designed for this purpose. The models of mass loss are provided and validated by statistical methods. Gravimetric indices are computed, to compare the mass loss in different cases. Differences are noticed in the mass-loss trend at different power of the ultrasound generator. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79944860","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":"On the Free Recovery Bending Shape Memory Effect in Powder Metallurgy FeMnSiCrNi","authors":"L. Ciurcă, B. Pricop, M. Popa, Victor Daniel Apostol, L. Bujoreanu","doi":"10.35219/mms.2021.3.01","DOIUrl":"https://doi.org/10.35219/mms.2021.3.01","url":null,"abstract":"This paper presents the results of an original experimental study on the training capacity of a powder metallurgy (PM) FeMnSiCrNi shape memory alloy (SMA). The specimens were sintered under protective atmosphere from blended elemental powders, 50 vol.%. of alloy particles being mechanically alloyed. Lamellar specimens, hot rolled to 1 mm thickness, were bent against cylindrical calibres with five decreasing radii, to induce cold shapes with higher and higher deformation degree, as compared to the straight hot shape. During the training procedure, bent specimens were heated with a hot air gun, and developed free-recovery shape memory effect (SME) and partially deflected, by reducing their curvature. The first set of experiments involved fastening the specimens at one end, heating it and monitoring free end’s displacement by means of cinematographic analysis. Within the second set of experiments, both cold and hot shapes were recorded and digitalized and their chord’s length (b) and circle segment height (a) were measured and the radius was determined as R = a/2 + b2/8a for the cold (Rc) and hot shapes (Rh). Finally, the shape recovery degree was calculated for the nth calibre as Δrecn = (Rhn-Rrn)/(Rhn-1-Rrn) and the variation of Δrecn with calibre’s radius was discussed. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81964949","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":"Application of the Natural Cellulosic Supports for the Treatment of the Industrial Effluents","authors":"A. Bondarev","doi":"10.35219/mms.2021.3.08","DOIUrl":"https://doi.org/10.35219/mms.2021.3.08","url":null,"abstract":"Wastewater treatment is one of the most important concerns of the research studies in the field of environmental protection. The current study relates to the removal of Crystal violet dye from aqueous solutions through adsorption experiments onto natural cellulosic supports. \u0000Various waste materials that have in their composition lignocellulose are adsorbent supports with low costs for the removal of heavy metal ions and dyes from aqueous solutions. \u0000The use of chemically modified sawdust to obtain an inexpensive adsorbent for removing the Crystal violet dye (CV) from synthetic aqueous solutions has been presented in this research paper. The influence of some important parameters such as: initial dye concentration, adsorbent dose, contact time and temperature on adsorption efficiency for this dye removal have been studied. The Freundlich, Langmuir and Temkin mathematical models have been used to evaluate the data of Crystal violet adsorption from aqueous media using wood sawdust. \u0000The research study shows that beech wood sawdust (Fagus sylvatica), as an agricultural waste which is readily available and relatively inexpensive has the potential to be an applicable alternative adsorbent for Crystal violet dye removal from industrial effluents. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75053491","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":"The Correlation Between the Operating Conditions of an Oil Tanker and Fuel Consumption","authors":"M. Lupchian","doi":"10.35219/mms.2021.3.05","DOIUrl":"https://doi.org/10.35219/mms.2021.3.05","url":null,"abstract":"This paper presents a calculation method to determine optimum operating conditions of power plants installations with internal combustion engines used on ships. The scope of this document is to make a minimum fuel consumption calculation using software Engineering Equation Solver. Analysing several operating regimes, the specific consumption of heavy fuel used on the main engine of the oil tanker is calculated. Vessel must operate at the parameters for which it was designed and built, thus satisfying all technical and economic aspects. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85494416","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":"Determining the Maintainability of Burning Ovens from Cement Factory","authors":"T Vasiu, A. B. Berghian, Corneliu Birtok Baneasa","doi":"10.35219/mms.2021.2.03","DOIUrl":"https://doi.org/10.35219/mms.2021.2.03","url":null,"abstract":"For any industrial entity put into operation, it is of interest to its ability to fulfil its mission under certain conditions, at a given time or during a given period of time, assuming that the means of maintenance are provided. This represents availability and is a complex form of system / product quality, as it includes both reliability and maintainability. Availability can be increased by: maximum reliability, maintenance, respectively by maximum maintainability, correct use of equipment / machines, renewal, optimization of reliability and maintainability characteristics, but provided that such balancing does not lead to contradictory solutions. The availability of a product will be higher the more reliable it is and requires less maintenance. It should be borne in mind that in order to ensure a certain level of reliability, maintenance costs must not exceed 10...20% of the purchase price of the product each year [1]. Restoration of reliability to a normal level is achieved through corrective or preventive maintenance. In practice, a compromise is sought between the purchase price, the service imposed and the accepted risk, as in order to achieve availability through reliability, very reliable parts must be used, which cost 5-10 times more than usual [2]. Maintenance-based availability results from the consideration that reliability is a probability of trouble-free operation over a period of time. Reliability is technically and financially limited. Defects in the initial period of operation of the product, as well as those in the final period derive from inevitable physical phenomena, and defects in the maturity period have a normal accidental character. In addition, the reliability can deteriorate over time even during storage, thus causing additional damage. Reliability is restored to its normal level through corrective or preventive maintenance, as failures are foreseeable or unpredictable. Product availability is the result of a combination of reliability and maintainability and they support each other. Increasing the maintainability of products leads to increased availability. In this case, the real maintainability of a burning oven of a cement factory was studied, with the aim of finding practical solutions to increase the service life. Achieving the proposed objective required monitoring the operation / failure of such equipment for nine months and statistical processing of the information obtained. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"612 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77022105","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":"Research on Construction and Sizing of the Metal Structure of a Winding Installation","authors":"M. Nan, Dorina Bădiță Popescu, D. Grecea, Cosmin Vitan, Bogdan Brănișteanu","doi":"10.35219/mms.2021.2.02","DOIUrl":"https://doi.org/10.35219/mms.2021.2.02","url":null,"abstract":"The paper focuses on the design of the metal tower for the sinking of Netiș de-ventilating shaft in Râul Mare Retezat hydro-energetic setup. The analytical calculation of sizing and verification of the metal structure is doubled by the graphic simulation with speciality software, in view of obtaining results as close as possible to the real exploitation conditions of the tower. The tower of the de-ventilating shaft is considered to be a temporary construction, and its component parts will be decommissioned once the sinking is finalized. The tower is made up of metal structures in four transoms, 3 being mounted with junction plates and screws, the fourth being the roof.","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"476 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76999487","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":"Mathematical Modeling of the Cold Rolling Process and Heat Treatment for DC01 Steel","authors":"M. Neacsu","doi":"10.35219/mms.2021.2.06","DOIUrl":"https://doi.org/10.35219/mms.2021.2.06","url":null,"abstract":"The paper presents the elaboration of a mathematical model of the cold strip rolling process combined with the recrystallization annealing after the rolling at LBR Liberty Galati.The elaborated mathematical model allows the prediction of the mechanical properties of cold rolled strips subsequently subjected to a heat treatment.The realization of this mathematical model was based on statistical measurements of the mechanical properties Rm, Rp0.2 (Rc) and A5 for the rolled steel strip DC01 from Liberty Steel Galati. To achieve this mathematical model, the active experiment method was used.With the help of this mathematical model, it is possible to optimize the rolling process by significant savings of time and materials in the process of testing the mechanical properties for cold rolled tape, but also by choosing the most appropriate process parameters. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73589245","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":"Considerations Regarding the Evolution of the Solidified Crust at the Continuous Casting Steel","authors":"M. Bordei","doi":"10.35219/mms.2020.4.04","DOIUrl":"https://doi.org/10.35219/mms.2020.4.04","url":null,"abstract":"The continuous casting of the steel can cause cracks on the surface or inside, which arise due to thermal and mechanical stresses. To eliminate these defects, mathematical models are drawn up with which temperature fields, expansions and stresses can be determined. The purpose of making these models is to locate the areas with a high risk of cracking so that, finally, the continuous casting machines and working conditions can be modified, so as to eliminate, or at least diminish, the defects. The knowledge of the thermal state of the steel in the continuous casting machine is necessary for the transposition on mathematical bases of the technological process and the elaboration of some simulation models of the solidification, which would allow the optimization of the afferent plant. The proposed mathematical model takes into account when studying the heat transfer phenomena in the tundish the convective motion of the steel, which influences the thickness of the solidified crust and the evolution of the temperature in the section of the continuously cast steel thread. By running the simulation program were determined the variation of the thickness of the solidified crust as a function of time, overheating in the crystallizer and convection coefficient.","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79505786","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":"Considerations Regarding the Evolution of the Steel Thermal State in the Continuous Casting Plant","authors":"M. Bordei","doi":"10.35219/mms.2020.4.05","DOIUrl":"https://doi.org/10.35219/mms.2020.4.05","url":null,"abstract":"In continuous casting it is very important that the cooling system is correctly dimensioned. Improper cooling conditions can reduce the quality of the finished product and cause perforations of the solidified crust. In order to be able to minimize the occurrence of defects, it is preferable that, under the conditions of a given cooling system, the temperature distribution in the steel wire be known. It is also necessary to know the thickness of the solidified crust, especially immediately below the crystallizer, because a thin crust at this level can be perforated due to the ferrostatic pressure of the steel. The knowledge of the thermal state of the steel in the continuous casting installation is necessary for the transposition on mathematical bases of the technological process and the elaboration of some models of simulation of the solidification, which would allow to optimize the operation of the afferent installations. By considering the convection motion can be explained the influence of electromagnetic agitation and deformation of the steel wire on the incompletely solidified area on the quality and structure of cast steels; convective currents reduce overheating, which leads to a decrease in columnar crystallization in favour of axial crystallization. By running the simulation program were determined the variation of the thermal flux at different levels in the tundish, as well as the evolution of the temperature at the surface of the continuously cast steel thread.","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78800164","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":"Real-Time Raindrop Detection Based on Deep Learning Algorithm","authors":"F. Marin, M. Marin","doi":"10.35219/mms.2020.4.09","DOIUrl":"https://doi.org/10.35219/mms.2020.4.09","url":null,"abstract":"The goal of this research is to develop an in-vehicle computerized system able to detect the raindrops on windshield and warn the driver and start the windscreen wiper in order to avoid that computer vision to acquire blurred images. This feature is important in order to develop Advanced Driver Assistance System based on computer vision. The system should be able specific scenarios that do not allow the ADAS computer vision feature to work properly. Rain drop detection will allow a more reliable Advanced Driver Assistance System.","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77635049","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}