Ciência & Tecnologia dos Materiais最新文献_第7页

In the search of nanocrystallinity in tool-steel chips 在工具钢切屑中寻找纳米结晶度

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.07.016

S.C. Godinho, R.F. Santos, M.T. Vieira

引用次数: 3

Synthesis and structure of Bi5FeTi3O15 ceramics Bi5FeTi3O15陶瓷的合成与结构

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.04.006

Agata Lisińska-Czekaj , Julian Plewa , Dionizy Czekaj

引用次数: 4

MDF and PB activated carbons for adsorption of dyes from liquid phase MDF和PB活性炭对液相染料的吸附

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.08.001

J.A.F.L. Gomes, B.C. Azaruja, P.A.M. Mourão

{"title":"MDF and PB activated carbons for adsorption of dyes from liquid phase","authors":"J.A.F.L. Gomes, B.C. Azaruja, P.A.M. Mourão","doi":"10.1016/j.ctmat.2016.08.001","DOIUrl":"10.1016/j.ctmat.2016.08.001","url":null,"abstract":"<div><p>The presence of pollutants in water is a recurring issue that is continuously addressed by governmental, intergovernmental, hybrid and non-governmental organizations and their action programs. Activated carbons (ACs) are currently used as adsorbents for waste water treatment. Combining the need to create and improve new carbon materials with the use and recovery of industrial by-products as precursors, we can achieve a balance between the high performance of these type of carbon adsorbents, cheap and sustainable sources of precursors.</p><p>AC samples were produced from medium-density fibreboard (MDF) and particleboard (PB) in monolithic form trough physical activation with carbon dioxide (CO<sub>2</sub>) and chemical activation with K<sub>2</sub>CO<sub>3</sub>. Physical activated carbons were found to be essentially microporous with narrow pores and apparent surface areas (A<span>bet</span>) between 804 and 926 m<sup>2</sup>/g and chemical activated samples present wider pores, with A<span>bet</span> ranging from 951 to 1032 m<sup>2</sup>/g.</p><p>Liquid phase adsorption studies were made for several dyes both in a static and dynamic adsorption modes. In static mode high values of removal were achieved after 5h, being this the time period used in the dynamic experiments, where some samples reached almost 100% removal.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.08.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90735222","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

Nondestructive testing in microfabrication using bacteria 利用细菌进行微加工的无损检测

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.09.002

T.J. Ferreira , A.R. Farinha , T.G. Santos , R. Miranda , C.C.C.R. Carvalho , M.T. Vieira

{"title":"Nondestructive testing in microfabrication using bacteria","authors":"T.J. Ferreira , A.R. Farinha , T.G. Santos , R. Miranda , C.C.C.R. Carvalho , M.T. Vieira","doi":"10.1016/j.ctmat.2016.09.002","DOIUrl":"10.1016/j.ctmat.2016.09.002","url":null,"abstract":"<div><p>Micromanufacturing has increased rapidly at scientific, technological and industrial levels. However, this evolution has not been followed by a parallel development of Non Destructive Testing (NDT) techniques. The available techniques are, generally, unable to detect microdefects. In this work, two types of microgeometries were produced by Micro Powder Injection Molding (μPIM) of stainless steel AISI316L: specimens for tensile tests (simple geometry) and microscrews (complex geometry). During the process optimization, different injection conditions of temperature and pressure were tested, as well as various temperatures for thermal debinding and sintering. Throughout the process, detectable and undetectable defects by NDT techniques were produced, which were used in the assays to assess the role of bacteria in the detection of defects. After adding bacterial suspensions of <em>Staphylococcus aureus</em> or <em>Rhodococcus erythropolis</em> cells, the microcomponents were subjected to magnetic or electric fields to facilitate mobility of bacteria towards the defects. This new methodology to detect defects produced during microfabrication can be a good solution for inspection of microdefects.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.09.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88673970","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

Shear resistance of concrete reinforced with ultra-high strength steel fibres 超高强度钢纤维增强混凝土的抗剪性能

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.04.004

José Gomes , Carlos Sousa , Mário Pimentel , Ana Maria Proença , A. Serra Neves

{"title":"Shear resistance of concrete reinforced with ultra-high strength steel fibres","authors":"José Gomes , Carlos Sousa , Mário Pimentel , Ana Maria Proença , A. Serra Neves","doi":"10.1016/j.ctmat.2016.04.004","DOIUrl":"10.1016/j.ctmat.2016.04.004","url":null,"abstract":"<div><p>In order to evaluate the performance of high strength concrete reinforced with Dramix 5D 65/60 BG fibres, with non-deformable hook and ultra-high tensile strength, 24 beams were subjected to shear, with different fibre content (0, 15, 30 and 50kg/m<sup>3</sup>), with and without stirrups in the shear span. In a second test campaign, 18 of those beams were tested again in the opposite end, with a variable shear span/effective depth (<em>a</em>/<em>d</em>) ratio in order to evaluate the influence of this parameter in the shear crack pattern and shear resistance. A probabilistic approach was followed to derive the corresponding design value of the shear strength (a procedure herein named by Design Assisted by Testing, DAT), which was then compared with the design shear strength determined according to recommendations of RILEM, EHE and FIB. Test results of both campaigns showed a significant increase in shear strength in relation to beams without fibres. Besides that, the design values of the shear strength derived from test results (DAT) were considerably higher than the design shear resistance provided by design codes.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.04.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78376158","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: 2

Mechanical behaviour analysis of polyester polymer mortars reinforced with tire rubber fibres 轮胎橡胶纤维增强聚酯聚合物砂浆力学性能分析

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.07.009

S.P.B. Sousa , M.C.S. Ribeiro , E.M. Cruz , G.M. Barrera , A.J.M. Ferreira

{"title":"Mechanical behaviour analysis of polyester polymer mortars reinforced with tire rubber fibres","authors":"S.P.B. Sousa , M.C.S. Ribeiro , E.M. Cruz , G.M. Barrera , A.J.M. Ferreira","doi":"10.1016/j.ctmat.2016.07.009","DOIUrl":"10.1016/j.ctmat.2016.07.009","url":null,"abstract":"<div><p>Tires effective reutilization has become an important research topic in recent years due to the stockpiles increase that creates environmental problems. Recent European regulations forbid the tires burning and landfilling, setting several recycling objectives. Within this context, the reutilization of tire rubber recyclates into cement and polymer concrete materials, as reinforcement or aggregate replacement, has received lately a great attention. The present work aim is to analyse the modifications induced by tire rubber addition in the mechanical properties of polyester based polymer mortars (PM). The effect of different tire rubber fibre amounts (0.1, 0.4 and 0.5wt.%) were analysed in this investigation. Plain polymer mortar was also prepared for comparison. Mechanical behaviour of both reinforced and plain polymer mortars formulations was assessed by flexural and compressive tests. Flexural and compressive strength improvements were particularly significant for PM trial formulation reinforced with the higher amount of tire rubber fibres. The observed trend on mechanical properties seems to indicate that higher increases could be achieved with higher amounts of tire rubber fibres. Thus, further experiments will be required in order to determine the critical amounts of rubber fibre reinforcement that define the turning points on material trend behaviour of PM.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.07.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83665020","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: 8

Adsorption of MCPA, 2,4-D and diuron onto activated carbons from wood composites 木质复合材料活性炭对MCPA、2,4- d和diuron的吸附研究

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.07.005

I.P.P. Cansado, P.A.M. Mourão, J.A.F.L. Gomes, V. Almodôvar

引用次数: 21

Study of the interaction between asphalt and recycled plastics in new polymer modified binders (PMB) 新型聚合物改性粘结剂(PMB)中沥青与再生塑料相互作用的研究

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.04.005

Liliana Costa , Sara Fernandes , Hugo Silva , Joel Oliveira

引用次数: 9

Mechanical behaviour assessment of unsaturated polyester polymer mortars filled with nano-sized Al2O3 and ZrO2 particles 纳米Al2O3和ZrO2颗粒填充不饱和聚酯聚合物砂浆的力学性能评价

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.08.002

S.P.B. Sousa , M.C.S. Ribeiro , P.R.O. Nóvoa , C.M. Pereira , A.J.M. Ferreira

{"title":"Mechanical behaviour assessment of unsaturated polyester polymer mortars filled with nano-sized Al2O3 and ZrO2 particles","authors":"S.P.B. Sousa , M.C.S. Ribeiro , P.R.O. Nóvoa , C.M. Pereira , A.J.M. Ferreira","doi":"10.1016/j.ctmat.2016.08.002","DOIUrl":"10.1016/j.ctmat.2016.08.002","url":null,"abstract":"<div><p>There are several ways to change the final properties of composite materials, but the most common one is by adding different types of modifier fillers to the polymeric matrix. Over the last years, nano fillers have brought some interesting properties to composites. Until now, only few works were published concerning the effective impacts of resin binder modification with nano oxides, on mechanical properties of polymer mortars (PM). In this study, unsaturated polyester based PMs with enhanced mechanical performance are developed through polymer modification with nano-sized Al<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub> particles. Samples without and with nanoparticles (2.5 resin wt.%) were produced, and their mechanical/physical properties assessed by flexural, compressive and Shore D hardness tests. The PM modified with nano zirconia showed better mechanical performance compared to the unmodified PM; more thorough studies are nevertheless required in order to improve mix design formulations towards further enhancement of mechanical behaviour.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.08.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86360921","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: 12

In vitro study of platelet behaviour on titanium surface modified by plasma 血浆修饰钛表面血小板行为的体外研究

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 DOI: 10.1016/j.ctmat.2016.09.003

J.O. Vitoriano , C. Alves Jr. , D.C. Braz , H.A. Rocha , R.C. Lima da Silva

{"title":"In vitro study of platelet behaviour on titanium surface modified by plasma","authors":"J.O. Vitoriano , C. Alves Jr. , D.C. Braz , H.A. Rocha , R.C. Lima da Silva","doi":"10.1016/j.ctmat.2016.09.003","DOIUrl":"10.1016/j.ctmat.2016.09.003","url":null,"abstract":"<div><p>Biomedical devices introduced in the human body interact initially with blood cells, their success being dependent on the result of this interaction. This work aimed to obtain optimum biocompatibility and hemocompatibility of the titanium by plasma treatment. For this, discs of commercially pure titanium (CP) were subjected to plasma nitriding using different mixture of nitrogen and hydrogen; the effect of addition of hydrogen to the nitriding plasma was investigated. Before and after treatment, samples were evaluated in terms of topography and wettability using atomic force microscopy and sessile drop tests, respectively. The titanium biological response was evaluated <em>in vitro</em> through the application of platelet-rich plasma (PRP) on the surfaces modified and analysis of their behaviour from the point of view of surface tension and cell adhesion. Surface properties, such as roughness and wettability, were sensitive to the hydrogen/nitrogen ratio in the nitriding plasma, suggesting a strategy for producing different surfaces of biomedical devices. Results showed to be possible to obtain surfaces with different response to the adhesion of platelets, covering different applications.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.09.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84801996","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: 2