材料科学与应用期刊(英文)最新文献_第4页

Mechanical Properties of Terminalia catappa from Ghana 产自加纳的弹射木的力学特性

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.135018

G. A. Quartey

{"title":"Mechanical Properties of <i>Terminalia catappa</i> from Ghana","authors":"G. A. Quartey","doi":"10.4236/msa.2022.135018","DOIUrl":"https://doi.org/10.4236/msa.2022.135018","url":null,"abstract":"Ghana is rich in forest resources, of which Terminalia catappa, a wood species of common occurrence is one. Even though sometimes it is used for decorative purposes, however, it grows in the wild. It grows in almost all the regions of the country and does well in the tropics. The parts of the tree such as the leaves, fruits and seeds have been known to be very useful for medicinal and other uses. Some work on the strength properties of the leaves and other parts has also been done, however, strength properties of the wood are yet to be explored. In this study, its mechanical properties such as bending strength, compression parallel to the grain, and shear parallel to the grain properties were determined. The British (BS 373, 1957) and American Society of Testing Materials’ specifications (ASTM D143, 1983) using testing methods for small, clear specimens of wood were used in determining the properties. The results showed that at 18% moisture content the wood has a density of 520 kg/m 3 with a mean modulus of rupture of 86.04 Mpa, compressive strength parallel to the grain of 42.02 Mpa, modulus of elasticity of 10,500 Mpa, and shear strength parallel to the grain of 16.42 N/mm 2 . These strength properties are comparable to that of Strombosia glaucescens. Therefore, T. catappa can be used in applications where this species is used.","PeriodicalId":68376,"journal":{"name":"材料科学与应用期刊(英文)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513250","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: 1

Effects of Vanadium on Structure and Tensile Properties of Tempcore Steel Bars 钒对高温钢结构和拉伸性能的影响

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.135019

H. Khalifa, A. El-Kady

引用次数: 2

Application and Perception of Potassium Iodide Following Silver Diamine Fluoride Treatment 二胺氟化银治疗后碘化钾的应用及感知

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.139031

Christian Ramlal, Nelson Triana

引用次数: 0

Determination of the Bromine, Manganese and Antimony in Nicotiana tabacum Solanaceae by Using the Neutron Activation Analysis Technique 中子活化分析法测定茄科烟草中溴、锰、锑的含量

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.132007

T. M. Filho, E.C.B. Ferreira, J. Berretta, M. C. Pereira

引用次数: 1

Hydrogen Solubility in Liquid and Solid Pure Aluminum—Critical Review of Measurement Methodologies and Reported Values 纯铝在液体和固体中的氢溶解度——测量方法和报道值的关键综述

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.134011

P. Anyalebechi

{"title":"Hydrogen Solubility in Liquid and Solid Pure Aluminum—Critical Review of Measurement Methodologies and Reported Values","authors":"P. Anyalebechi","doi":"10.4236/msa.2022.134011","DOIUrl":"https://doi.org/10.4236/msa.2022.134011","url":null,"abstract":"Reliable information on the solubility of hydrogen in aluminum and its alloys is critical to the effort of the aluminum industry to control and ameliorate the usually deleterious effects of hydrogen on the properties and performance of pure aluminum and aluminum alloy products. Unfortunately, there is a significant disparity between published values of hydrogen solubility in pure aluminum and aluminum alloys. This is because the measurement of the extremely low soluble hydrogen concentration in aluminum and its alloys is experimentally difficult. Also, the reproducibility, accuracy, and reliability of the hydrogen solubility values are very sensitive to the measurement techniques, test conditions, chemical composition, and state of the aluminum sample. Thus, no serious discussion of the reliability of reported values of hydrogen solubility in aluminum and its alloys can be undertaken without a critical assessment of the fundamental principles of the experimental techniques used in the determination of the reported values. In this article, a critical review of the fundamental principles of the experimental techniques used in the measurement of hydrogen solubility in liquid and solid pure aluminum and aluminum alloys is presented. In addition, the reliability and possible accuracy of reported values of hydrogen solubility in solid and liquid pure aluminum are critically assessed. Empirical equations for calculating hydrogen solubility in liquid and solid pure aluminum as a function of temperature and pressure, derived from the most reliable sets of data are recommended. At 101.3 kPa (1 atm.) hydrogen partial pressure, the most reliable values of hydrogen solubility at the melting point (833 K) of pure aluminum are 0.71 cm 3 /100g (i.e., 6.32 × 10 −5 wt.%","PeriodicalId":68376,"journal":{"name":"材料科学与应用期刊(英文)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513143","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: 5

Dependence of Thermoformed Mouthguard Thickness on Model Height in Single-Layer and Laminated Mouthguards 单层和层压式热成型护齿器厚度与模型高度的关系

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.138028

Mutsumi Takahashi, Yogetsu Bando

引用次数: 2

Application of the Mechanical Threshold Stress Model to Large Strain Processing 机械阈值应力模型在大应变加工中的应用

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.135016

P. Follansbee

引用次数: 1

Tensile and Microstructure for One Ti Alloy Plate 一种钛合金板的拉伸和显微组织

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.136025

Liying Zeng, Qian Li

引用次数: 0

Factors Affecting Thermal Shrinkage of Mouthguard Sheet during Thermoforming: Model Shape and Sheet Material Thickness 影响护齿板热成型热收缩的因素:模型形状和板材厚度

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.134009

Mutsumi Takahashi, Yogetsu Bando

{"title":"Factors Affecting Thermal Shrinkage of Mouthguard Sheet during Thermoforming: Model Shape and Sheet Material Thickness","authors":"Mutsumi Takahashi, Yogetsu Bando","doi":"10.4236/msa.2022.134009","DOIUrl":"https://doi.org/10.4236/msa.2022.134009","url":null,"abstract":"The effectiveness and safety of the mouthguard depend on the sheet material thickness. The thickness of the thermoformed mouthguard is affected by the model undercut and the thermal shrinkage that occurs when the ex-truded-molded sheet is reheated. The aim of this study was to clarify the influence of the undercut amount of the model and the thickness of the sheet material on the thermal shrinkage of the extruded sheet. The mouthguard sheet used ethylene-vinyl acetate resin with a thickness of 4.0 mm (4M) and 3.0 mm (3M) and was manufactured by extrusion molding. The working models were three hard gypsum models with the undercut amount on the labial side trimmed to 0˚ (U0), 10˚ (U10), and 20˚ (U20). Mouthguard thickness after vacuum formation was compared between the conditions formed so that the extrusion direction was vertical (condition V) or parallel (condi-tion P) to the model midline. Differences in the reduction rate of the mouthguard thicknesses of the labial and buccal side depending on the sheet extrusion direction, model angle, and sheet material thickness were analyzed by three-way ANOVA and Bonferroni method. The reduction rate of the thickness in condition P was significantly greater than in condition V under all conditions except U0-4M on the labial side and U0-4M and U10-4M on the buccal side. In all models, the reduction rate of the thicknesses was in than in in the same extrusion direction. In 4M and the reduction rate of the thicknesses tended to increase as the amount undercut increased in each extrusion direction. This study suggested that a model a large amount of undercut on the labial side or a thin sheet had a significant effect on the thermal shrinkage of the mouthguard sheet during thermoforming, which leads to the thinning of the mouthguard.","PeriodicalId":68376,"journal":{"name":"材料科学与应用期刊(英文)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512765","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: 1

PLA-Starch Microparticles Containing Clays Focusing Controlled Release of Rifampicin 含有粘土的pla -淀粉微粒聚焦控释利福平

材料科学与应用期刊(英文) Pub Date : 2022-01-01 DOI: 10.4236/msa.2022.137026

L. M. Brito, M. Tavares

{"title":"PLA-Starch Microparticles Containing Clays Focusing Controlled Release of Rifampicin","authors":"L. M. Brito, M. Tavares","doi":"10.4236/msa.2022.137026","DOIUrl":"https://doi.org/10.4236/msa.2022.137026","url":null,"abstract":"Polymer nanocomposites have been successfully used as excipients in pharmaceutical technology because of the convenient features that make them suitable for many applications, especially in controlled drug delivery therapies. The objective of this work was to prepare and characterize PLA and starch microparticles containing Viscogel B8 organophilic clay as a matrix for controlled release of rifampicin, one of the most spread drugs for tuberculosis treatment. The systems obtained by the spray drying technique were charac-terized by DRX, FTIR, SEM and low-field NMR. In addition, dissolution tests were performed on simulated gastric fluid. The micrographs indicate that the presence of the drug caused a small change in the shape and size of the particles. In the presence of the drug, the particles were spherical and presented wider size distribution. The XRD assays didn’t show crystalline peaks of rifampicin in the microparticles, which suggests that rifampicin exists in an amorphous solid solution inside the starch-PLA particles. The mathematical model of Baker-Lonsdale was chosen for the treatment of the dissolution data, describing the controlled release of the drug from the matrix by a spherical diffusion process. The results suggest that the proposed release system may be used for the delivery of orally administered drugs, such as rifampicin. treatment, reducing the required doses and systemic side effects.","PeriodicalId":68376,"journal":{"name":"材料科学与应用期刊(英文)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513268","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