Rem-Revista Escola De Minas最新文献_第6页

Fault condition detection for a copper flotation process based on a wavelet multi-scale binary froth image 基于小波多尺度二值泡沫图像的铜浮选过程故障状态检测

Rem-Revista Escola De Minas Pub Date : 2015-06-01 DOI: 10.1590/0370-44672015680195

Lu Ming, Gui Wei-hua, P. Tao, Cao Wei

引用次数: 5

Rolstoel van de Overdracht van het aluminium de Hand Vouwende met de Rem van het Handvat 轮椅的铝转移手折叠与刹车的处理

Rem-Revista Escola De Minas Pub Date : 2015-06-01 DOI: 10.1590/0370-44672015680070

Hamilton José de Mello, Diego Rafael de Mello, Eduardo Carlos Bianchi, Paulo Roberto de Aguiar, Doriana M. D’Addona

{"title":"Rolstoel van de Overdracht van het aluminium de Hand Vouwende met de Rem van het Handvat","authors":"Hamilton José de Mello, Diego Rafael de Mello, Eduardo Carlos Bianchi, Paulo Roberto de Aguiar, Doriana M. D’Addona","doi":"10.1590/0370-44672015680070","DOIUrl":"https://doi.org/10.1590/0370-44672015680070","url":null,"abstract":"There has been a great advance in the grinding process by the development of dressing, lubri-refrigeration and other methods. Nevertheless, all of these advances were gained only for continuous cutting; in other words, the ground workpiece profile remains unchanged. Hence, it becomes necessary to study grinding process using intermittent cutting (grooved workpiece – discontinuous cutting), as little or no knowledge and studies have been developed for this purpose, since there is nothing found in formal literature, except for grooved grinding wheels. During the grinding process, heat generated in the cutting zone is extremely high. Therefore, plenty of cutting fluids are essential to cool not only the workpiece but also the grinding wheel, improving the grinding process. In this paper, grinding trials were performed using a conventional aluminum oxide grinding wheel, testing samples made of AISI 4340 steel quenched and tempered with 2, 6, and 12 grooves. The cylindrical plunge grinding was performed by rotating the workpiece on the grinding wheel. This plunge movement was made at three different speeds. From the obtained results, it can be observed that roughness tended to increase for testing sample with the same number of grooves, as rotation speed increased. Roundness error also tended to increase as the speed rotation process got higher for testing the sample with the same number of grooves. Grinding wheel wear enhanced as rotation speed and number of grooves increased. Power consumed by the grinding machine was inversely proportional to the number of grooves. Subsuperficial microhardness had no significant change. Micrographs reveal an optimal machining operation as there was no significant damage on the machined surface.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"22 1","pages":"229-238"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89248530","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

Tempering effect on the localized corrosion of 13Cr4Ni0.02C and 13Cr1Ni0.15C steels in a synthetic marine environment 回火对13Cr4Ni0.02C和13Cr1Ni0.15C钢在合成海洋环境中局部腐蚀的影响

Rem-Revista Escola De Minas Pub Date : 2015-06-01 DOI: 10.1590/0370-44672015680040

R. Mendonça, N. A. Mariano

{"title":"Tempering effect on the localized corrosion of 13Cr4Ni0.02C and 13Cr1Ni0.15C steels in a synthetic marine environment","authors":"R. Mendonça, N. A. Mariano","doi":"10.1590/0370-44672015680040","DOIUrl":"https://doi.org/10.1590/0370-44672015680040","url":null,"abstract":"Primarily, tempering is used in martensitic stainless steels with low carbon in order to change their mechanical properties. However, it also modifies the corrosion properties; usually depending on the temperature and duration of the heat treatment. This work investigated the impact of tempering on the corrosion of 13Cr4Ni0.02C and 13Cr1Ni0.15C (% weight) steels. Samples were tempered at 650o, 700o and 750oC, characterized by optical microscopy and cyclic anodic polarization tests in a synthetic marine environment. The results showed differences in the microstructure of the 13Cr4Ni0.02C tempered samples, which changed from lath to lamellar with precipitates in the prior austenite grain boundaries. On the other hand, tempering did not affect the 13Cr1Ni0.15C microstructure. The anodic polarization tests showed that the pitting potential of the 13Cr4Ni0.02C samples decreased with the tempering temperature increasing. Similar values of pitting potential were found with the 13Cr1Ni0.15C tempered samples, which were lower than the 13Cr4Ni0.02C samples after tempering. It shows that even though the corrosion resistance of the 13Cr4Ni0.02C reduces when the tempering temperature was increased, it is better than that presented by 13Cr1Ni0.15C.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"21 1","pages":"201-206"},"PeriodicalIF":0.0,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86691541","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

Non linear elasto-plastic analysis of cylindrical cavity in rock mass using a Hoek-Brown criterion 基于Hoek-Brown准则的岩体柱状空腔非线性弹塑性分析

Rem-Revista Escola De Minas Pub Date : 2015-06-01 DOI: 10.1590/0370-44672015680155

Jefferson Tales Simão Simão, C. L. Nogueira

引用次数: 1

Evaluation of the hydration process of an industrial magnesia compound to obtain struvite crystals: a technique for recovering nutrients 工业氧化镁化合物获得鸟粪石晶体水化过程的评价:一种回收营养物质的技术

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680138

S. R. Castro, M. Araújo, L. Lange

{"title":"Evaluation of the hydration process of an industrial magnesia compound to obtain struvite crystals: a technique for recovering nutrients","authors":"S. R. Castro, M. Araújo, L. Lange","doi":"10.1590/0370-44672015680138","DOIUrl":"https://doi.org/10.1590/0370-44672015680138","url":null,"abstract":"A cristalizacao da estruvita como uma tecnica para recuperar nutrientes a partir de correntes de efluentes tem provado ser uma alternativa atrativa aos tratamentos convencionais. O processo torna se economicamente viavel com a reducao dos custos relacionados aos reagentes quimicos, especialmente os ions de magnesio. Assim, esse estudo avaliou o processamento de um composto industrial de magnesia, de baixo custo e elevado teor, na obtencao de suspensoes de hidroxido de magnesio atraves de uma reacao de hidratacao, utilizando diferentes agentes (solucao de acetato de magnesio e de cloreto de sodio, alem de agua). A condicao otima de hidratacao foi atingida em solucao de acetato com uma taxa de conversao a hidroxido de cerca 67%. A eficiencia das suspensoes obtidas como reagente alternativo, no processo de cristalizacao da estruvita, foi avaliada em termos da remocao de nutrientes, NH4+-N e PO43-P. Em condicoes experimentais de razao Mg2+:NH4+:PO43- igual a 1,5:1,0:1,25 e pH igual a 8,5, os melhores resultados foram obtidos pelo uso da suspensao de hidroxido de magnesio obtida em solucao de acetato, que promoveu remocoes de cerca de 62% e 67% de NH4+-N e PO43--P, respectivamente. Por fim, analises instrumentais confirmaram a formacao de cristais de estruvita em um grau de pureza que possibilita seu uso como potencial fertilizante.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"199 1","pages":"77-84"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73753261","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

Simulations of Vertimill Pilot Scale tests for Itabirite 依他必利的Vertimill中试试验模拟

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680014

D. Mazzinghy, J. Russo, R. Galery, C. Schneider

引用次数: 0

Otimização de projeto 设计优化

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680018

C. Carli, Peroni Rodrigo de Lemos

引用次数: 2

The columnar to equiaxed transition in the directional solidification of aluminum based multicomponent alloys 铝基多组分合金定向凝固中的柱状向等轴转变

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680237

O. Rocha, L. Gomes, D. J. Moutinho, I. Ferreira, Amauri Garcia

引用次数: 7

Geochemical fingerprint of siliceous, amphibolitic and magnetitic itabirite types of the region of Serra Azul – Quadrilátero Ferrífero, MG 蔚蓝山地区硅质、角闪石和磁性橄榄岩地球化学指纹图谱- Quadrilátero Ferrífero, MG

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680104

A. Alkmim, G. Sampaio, J. Dantas, A. T. Abreu, H. Nalini

{"title":"Geochemical fingerprint of siliceous, amphibolitic and magnetitic itabirite types of the region of Serra Azul – Quadrilátero Ferrífero, MG","authors":"A. Alkmim, G. Sampaio, J. Dantas, A. T. Abreu, H. Nalini","doi":"10.1590/0370-44672015680104","DOIUrl":"https://doi.org/10.1590/0370-44672015680104","url":null,"abstract":"Banded iron formations are important providers of information about the evolution of the hydrosphere, atmosphere, biosphere and lithosphere of the Earth. This study gathers data from the geochemical investigation of major, minor and trace elements (including rare earth elements) of the siliceous, amphibolitic and magnetitic types of itabirite from the Caue Formation, sampled in the Serra Azul region (Quadrilatero Ferrifero). Observing the trace elements described as tracers of detrital contamination can be inferred that the magnetitic itabirite has the highest contamination and that the siliceous type has the lowest one. Although there are differences in the total sum of REE in the three itabirite types of Serra Azul, there are no discrepancies in the REE spectrum of each type. The itabirite types have as common characteristics in their REE spectrum: i) positive Eu anomalies (Planavsky et al., 2010); ii) HREE enrichment in relation to the LREE; iii) ratios of (Sm/Yb) SN 1 (Bau & Moller, 1993). The magnetitic and the siliceous itabirites had positive Y anomalies, a common characteristic that appeared in some amphibolitic samples. On the other hand, the other amphibolitic samples had negative Y anomalies.","PeriodicalId":54498,"journal":{"name":"Rem-Revista Escola De Minas","volume":"51 1","pages":"37-42"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90770449","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

Reduced hydraulic model of Forquilha IV tailings dam 福尔库利哈四号尾矿坝的简化水力模型

Rem-Revista Escola De Minas Pub Date : 2015-03-01 DOI: 10.1590/0370-44672015680187

Eder Daniel Teixeira, P. Franca, Edna M. de F. Viana, M. T. C. Faria, A. Saliba, C. B. Martinez

引用次数: 0