The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science最新文献_第7页

Research on Some Freshwater Fish Catalase Activity - As a Potential Biomarker for Environmental Pollution 一些淡水鱼过氧化氢酶活性的研究——作为潜在的环境污染生物标志物

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.04

R. Crețu

{"title":"Research on Some Freshwater Fish Catalase Activity - As a Potential Biomarker for Environmental Pollution","authors":"R. Crețu","doi":"10.35219/mms.2021.4.04","DOIUrl":"https://doi.org/10.35219/mms.2021.4.04","url":null,"abstract":"In the last decade studies show that water pollution is a very serious problem, especially since the degree of water pollution plays a key role in the growth and fish multiplication. As a biomarker of environmental pollution, antioxidant enzymes such as catalase (CAT; EC 1.11.1.6) play an essential role in preventing the harmful effects of heavy metals in the tissues of fish. These researches were carried out to investigate the effect of various environment conditions and some pollutant agents on oxidative stress in some aquatic organisms. The enzymatic assay of CAT (in fish organs, e.g., liver, kidney, gill, intestine and brain, as well as in mixture of these organs) was carried out according to standard enzyme assay protocol. \u0000The results showed decrease of CAT activity: the enzymatic activity was 35.89 ± 1.02 µmol H2O2/min/mg protein to pH 7 and 6.59 ± 0.47 µmol H2O2/min/mg protein to pH 12. More, the enzymatic activity was 38.1 ± 0.3 µmol H2O2/min/mg protein to pH 3. Also, the catalase activity increased with 23 enzymatic units to a less dissolved oxygen concentration (6.2877 mg/L). \u0000Furthermore, this study indicated that heavy metals, such as Cr, Cu and Zn can inhibit biochemical reactions in various organs of fish. During exposure duration of the fish to a mixture of metal ions the catalase activity decreases from 35.89 ± 1.02 µmol H2O2/min/mg protein to 23.51 ± 2.85 µmol H2O2/min/mg protein. On the other hand, as a result of the response of the enzyme system, the catalase activity increases to 36.25 ± 3.22 µmol H2O2/min/mg protein. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"10 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72471426","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}

引用次数: 0

Analysis of the Wear Process of the Elements in the Braking System of Heavy Trucks 重型卡车制动系统元件磨损过程分析

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.13

M. Popa, B. Jurchiş

引用次数: 0

On the Corrosion of Two Types of Bronzes Under Cavitation 两种青铜在空化作用下的腐蚀研究

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.02

C. Dumitriu

引用次数: 3

CFD Modeling and Simulation of an Industrial Hall 某工业厂房的CFD建模与仿真

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.15

F. Marin, M. Marin

引用次数: 0

Researches on Soot Filtration Process by Comparing Simulation and Experimental Tests 煤烟过滤过程的仿真与实验对比研究

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.10

B. Jurchiş

{"title":"Researches on Soot Filtration Process by Comparing Simulation and Experimental Tests","authors":"B. Jurchiş","doi":"10.35219/mms.2021.4.10","DOIUrl":"https://doi.org/10.35219/mms.2021.4.10","url":null,"abstract":"In this paper, the main objective of using numerical simulation was to highlight and analyse details that are very difficult to highlight through experimental tests. The development of the simulation model was also done for predictive purposes. In other words, after validation of the model, it can be used to estimate the filter load in other conditions than the experimental ones, respectively to evaluate how the particulate filter affects the operation of the internal combustion engine. In order to achieve the desired result, the creation of the model was done in two stages, the first stage was the creation of a model containing all the components of the engine, except the particle filter in order to identify the parameters of the combustion process and pollutant emissions - model validated on the basis of the indicated pressure curves, and the second stage was to complete the initial model with a particle filter and validate it from the point of view of the pressure drop, respectively of the engine performance, the aim was to obtain a trend, respectively values similar to the experimental ones. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"112 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80794627","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}

引用次数: 0

Determination of Porosity in Fluidized-Bed Carburized P/M Compacts Using an Image Software Analysis 用图像分析软件测定流化床渗碳粉末冶金压坯的孔隙率

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-12-15 DOI: 10.35219/mms.2021.4.07

M. Marin, F. Marin

引用次数: 0

Studies and Research on Obtaining Multifunctional Thin Films by Magnetron-Assisted PVD Process 磁控管辅助PVD工艺制备多功能薄膜的研究

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-09-15 DOI: 10.35219/mms.2021.3.04

S. Boiciuc

引用次数: 0

A Study on the Wear Behaviour of Monolithic Mullite Materials for Dental Applications 牙科用整体莫来石材料的磨损性能研究

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-09-15 DOI: 10.35219/mms.2021.3.02

Perent Güler, B. Ertuğ, N. İ. Işıkcı, A. Kara

{"title":"A Study on the Wear Behaviour of Monolithic Mullite Materials for Dental Applications","authors":"Perent Güler, B. Ertuğ, N. İ. Işıkcı, A. Kara","doi":"10.35219/mms.2021.3.02","DOIUrl":"https://doi.org/10.35219/mms.2021.3.02","url":null,"abstract":"The aim of this study is to evaluate the potential use of the monolithic mullite samples for the dental applications. For this purpose, at first the monolithic mullite samples obtained by the powder metallurgy method have been characterized by the scanning electron microscopy (SEM) together with the EDS analysis. The pin-on-disk tribometer has been used to conduct the wear test in order to determine the volumetric loss. After the wear tests, the worn surfaces of the sintered mullite samples have been studied. The presence of the 3Al2O3.2SiO2 structure has been confirmed by the FT-IR spectroscopy through the observation of the characteristic Al-O-Si linkages at the spectra. The wear rate results derived from the volumetric losses have been measured to be around 2.42×10-6 mm3/Nm. This value has been found to be lower than those of alumina and alumina-mullite composites in the previous studies, which explains the higher wear resistance of these mullite materials. The room temperature friction coefficients of AS-1 and AS-2 samples have been determined to be 0.88 and 0.80, respectively. The wear behaviour of the samples has been correlated to the sintering temperature and the resultant relative density of the samples. The mullite samples obtained in this study have indicated better wear performance than the other materials (alumina and alumina-mullite composites) in spite of the usage of monolithic material. Therefore, this study suggests that the monolithic mullite materials have a potential to be exploited for the replacement of the previous ceramic-based dental materials. Further studies might contribute to the improvement of these materials to be utilized in the oral environment. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86845613","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}

引用次数: 0

Use of Taguchi Methods for Hierarchy of Influence Factors in the Application of Carbonitration in a Fluidized Bed Steel for 41Cr4 Steel 用田口法分析影响因素在41Cr4钢流化床渗碳工艺中的应用

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-09-15 DOI: 10.35219/mms.2021.3.07

Nelu Cazacu

{"title":"Use of Taguchi Methods for Hierarchy of Influence Factors in the Application of Carbonitration in a Fluidized Bed Steel for 41Cr4 Steel","authors":"Nelu Cazacu","doi":"10.35219/mms.2021.3.07","DOIUrl":"https://doi.org/10.35219/mms.2021.3.07","url":null,"abstract":"The work is based on carbonitriding in a fluidized layer with methane and ammonia gas applied to 41Cr4 steel samples. To achieve the best possible results, other factors must be taken into account, than those specific to carbonitring. It was necessary to use a partially factorial working procedure due to the increase in the number of factors. An A18 matrix has been used, with 18 lines of experiments in which three levels have been modified for 6 factors. The objective function was fixed at the final hardness after carbonitriding, hardening and tempering. The carbonitriding was performed in fluidized bed with granular solid ground and sorted to 0.1- to 0.16mm, and brought to fluidization with a mixture of methane and ammonia. The hardening has been done directly after carbonitriding in the fluidized bed. The experiments have been performed according to Taguchi Methods and the results indicate an optimal regime and the influence of the factors considered on the hardness after the thermo-chemical treatment and the thermal treatment. Metallographic analysis has been performed on the carbonitrided layer. \u0000","PeriodicalId":22358,"journal":{"name":"The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89704556","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}

引用次数: 0

Studies and Research on the Influence of Deposit Parameters on the Characteristics of Composite Coatings Ni-Al2O3 Obtained by Electrochemical Methods 沉积参数对电化学法制备Ni-Al2O3复合镀层性能影响的研究

The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science Pub Date : 2021-09-15 DOI: 10.35219/mms.2021.3.03

S. Boiciuc

引用次数: 0