bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural, Mechanical Properties and Corrosion Resistance of Ferritic Stainless Steel Welded by GTAW and Coated by Flame Spraying
Authors: Delgado-Venegas J. , Molina-Díaz A. , Ambriz-Rojas R.R. , Cuenca-Álvarez R. 
Published: October 2015

ABSTRACTFerritic stainless steels are widely used in transportation industry due to their exceptional performance regarding mechanical and corrosion properties. However, after a welding process, joints feature the sensitizing phenomenon because of the heat exchange from the torch affecting mechanical properties and corrosion resistance. This work describes the behavior firstly of mechanical properties of weld joints of ferritic stainless steel as base material without and with filler material (AISI 308L) by gas tungsten arc welding (GTAW). Operating parameters such as arc voltage, welding currrent, welding speed, feed speed, shielding gas flow were evaluated. Secondly, samples of weld joints were coated by flame spraying of composite particles in order to reduce the weight loss induced by corrosion in a salt spray (fog) apparatus. Changes induced from GTAW on the heat affected zone and Thermal Spraying on corrosion resistance, were monitored by optical and scanning electron microscopy, microhardness and longitudinal tensile testing. Results show that GTAW helps to control the size and the microstructure of heat affected zone improving simultaneously the mechanical properties. Meanwhile, welded joints covered by composite coatings feature a lower damage provided that the ceramic phase has been homogeneously dispersed.
Principles of Technology and Mechanical Properties of Structural Ceramics Based on the Ternary System SiC–B4C–CrB2
Authors: Chalgin Aleksei V. , Vikhman Sergei V. , Ordan’yan Sukyas S. , Danilovich Dmitry P. , Nechaeva Maria V. 
Published: October 2015

ABSTRACTThe aim of this research was to work out the technology of ceramics for finding optimal sintering temperatures and to study their mechanical properties. Samples were prepared from powders with different volumetric ratio of the components. The powders underwent a prolonged co-milling in a vibratory mill, followed by uniaxial pressing, cold isostatic pressing (CIP) and pressureless sintering in a vacuum furnace under an argon atmosphere. Hot pressing (HP) was applied to some powder formulations. This study showed that it is advisable to carry out the first stage of the heat treatment up to 1550 ̊C under vacuum, with the aim of refining the grain surface from the oxygen-containing impurities due to their dissociation and evaporation. The studied area of formulations has a very narrow range of sintering (1940-1945 ̊C). It was established that the sinterability of the materials is affected by the amount of silicon carbide in the ternary system. Under pressureless sintering, the relative density of the material directly depended on the volume fraction of SiC. However, a change in the concentration of B4C had no appreciable effect on the sinterability of the materials. The application of HP helped us to reduce the negative impact of large amounts of SiC. Under HP at temperatures close to Teut, a certain decompaction of materials was observed with a significant amount of B4C (3-5% loss in density).
Numerical Analysis Applied to Nonlinear Problems
Authors: León E. Pineda , Rodríguez-Castellanos A. , Aliabadi M.H. 
Published: October 2015

ABSTRACTThe present paper shows the applicability of the Dual Boundary Element Method to analyze plastic, visco-plastic and creep behavior in fracture mechanics problems. Several models with a crack, including a square plate, a holed plate and a notched plate are analyzed. Special attention is taken when the discretization of the domain is done. In Fact, for the plasticity and viscoplasticity cases only the region susceptible to yielding was discretized, whereas, the creep case required the discretization of the whole domain. The proposed formulation is presented as an alternative technique to study this kind of non-linear problems. Results from the present formulation are compared to those of the well-established Finite Element Technique, and they are in good agreement. Important fracture mechanic parameters such as KI, KII, J- and C- integrals are also included. In general, the results, for the plastic, visco-plastic and creep cases, show that the highest stress concentrations are in the vicinity of the crack tip and they decrease as the distance from the crack tip is increased.
Ceramic Refractory Compositions with Biosolubility Characteristics
Authors: Joaquín-Morales Ma.G. , Vargas-Gutiérrez G. , Rodríguez-Galicia J.L. , Vazquez-Carbajal G.I. , López-Cuevas J. 
Published: October 2015

ABSTRACTIn this work, we studied the dissolution of three different refractory compositions belonging to the ternary system SiO2-CaO-MgO into two Simulated Lung Fluids (SLF). The initial powder mixtures were uniaxially pressed and then sintered at 1300-1400 °C. The sintered samples were immersed for times from 1 to 21 days into a given SLF at 37 °C. The samples were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The dissolution of Ca2+, Mg2+ and Si4+ into the SLF was quantified by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The in vitro studies suggested that all the considered materials had a potential to show a diminished biopersistence in vivo, due to reasons that depended on their chemical and phase composition.
Influence of Heat Treatments on a NiTi Shape Memory Alloy Obtained Using Vacuum Induction Melting and Reprocessed by Plasma Skull Push-Pull
Authors: de Brito Simões Jackson , Pereira Francisco Fernando Roberto , Otubo Jorge , de Araújo Carlos José 
Published: October 2015

ABSTRACTShape memory alloys (SMA) are metallic attractive engineering materials due to their capacity to store pre-defined shapes through a thermally induced phase transition from a solid state. This paper aims to evaluate the influence of solubilization thermal treatments on a NiTi shape memory alloy originally fabricated by vacuum induction melting and then reprocessed by plasma melting followed by injection molding (Plasma Skull Push Pull process) into different metal molds (steel, aluminum, brass and copper) in order to compare the thermal properties regarding to its raw state. The thermal treatments of solubilization were carried out at 850°C in different times (2n function, n = 0, 1, 2 and 3, in hours). The influence of solubilizing treatments in the NiTi shape memory alloy was analyzed using the following characterization techniques: Differential Scanning Calorimetry (DSC) and Electrical Resistance as a function of Temperature (ERT). The results demonstrate that the solubilization heat treatments applied on the reprocessed NiTi shape memory alloy through the plasma skull push pull process, provides important changes in the phase transformation of the material. Therefore, it was demonstrated that it is necessary to solubilize the material after melting or remelting the NiTi shape memory alloy via this process to obtain mini-actuators products with homogeneous properties.
Determination of Recrystallization Kinetics and Activation Energy of Grain Growth Process of Cu-14Al-4Ni Shape Memory Alloy
Authors: Lima Emmanuel P. R. , de Lima Pedro C. , Nava Marcelo 
Published: October 2015

ABSTRACTThe non-ferrous shape memory alloys have, normally, two problems that hinder its use in industrial scale: the natural aging and grains growth. The first degrades the memory effect, while the second, observed during the processing of alloy, modifies the temperatures which the transformations occur. Thus, the study of kynetic of recrystallization is important for enabling the control of hardened state in function of treatment time, without causing excessive grain growth. Therefore, the objective of this study is to determine the kinetics of recrystallization of Cu-14Al-4Ni shape memory alloy, based on an empirical law of the formation of Jonhson-Mehl-Avrami, as well as their activation energies for grain growth process according to the empirical Arrhenius law. The alloy was vacuum melted in an induction furnace. After casting, the bulk samples of the alloy were homogenized for 24 hours, solubilized and hot rolled followed by water-quenching to initiate the recrystallization. Then, different samples were annealed at temperatures close to the peak, start and end of the DSC curve. Following the heat treatments, the samples were submitted to mechanical tests and the values of the properties were correlated to the fraction transformed for determination of recrystallization’s kinetic. For the characterization of the grain growth process, analyses in optical microscopy were accomplished and all annealed samples were examined by statistical metallography and the grain sizes were measured. After measurements, the ln[-ln(1-Yrec)] x ln(t) and the ln [D-Do] x 1/T diagrams were plotted to determine the parameters of Jonhson-Mehl-Avrami equation and the activation energy of the process, respectively. The results showed that the equation of the recrystallized fraction follows the empiric law of the formation of Jonhson-Mehl-Avrami for the considered property, as well as, also showed that the alloy Cu-14Al-4Ni is extremely sensitive to temperature variation in which the alloy is treated, having a dual kinetics of grain growth. In the first domain, between 670 and 710°C, the diagram provides a value for the activation energy equal to 39.32 KJ/mol, in the second domain, between 710 and 790°C, the diagram provides a value for the activation energy equal to 9.01 KJ/mol.
Experimental and Theoretical Study on Melting Kinetics of Spherical Aluminum Particles in Liquid Aluminum
Authors: Ramírez-Argáez Marco , Jardón Enrique , González-Rivera Carlos 
Published: October 2015

ABSTRACTIn this study a process analysis of the melting process of solid particles in a bath of same composition is performed using both experimental information and theoretical computations. An experimental setup was used to measure the thermal histories and to follow the evolution with time of the size of solid metallic spherical particles being melted in a metallic bath of same composition. For such a purpose, pure aluminum was used during the experiments for both solid particles and liquid bath. A mathematical model was also developed based on first principles of heat transfer to simulate the melting kinetics of a cold metallic spherical particle immersed in a hot liquid bath of same composition. The mathematical model was reasonably validated when compared against the experimental results obtained in this work. A process analysis of the melting process was performed to determine the effect of the initial temperature and size of the solid particle, the bath temperature and the convective heat transfer coefficient on the melting time and on the energy consumption.The analysis showed that the variable presenting the most significant effect on both the melting time and the energy consumption is the convective heat transfer coefficient between the particle and the bath, since an increment in such a parameter accelerates the melting process and saves energy. Therefore, proper stirring of the bath is highly recommended to enhance the melting of metallic alloying additions in the metallic baths.
VALIDAÇÃO ESTOCÁSTICA DE UM RECEPTOR RFID COM MÚLTIPLO ACESSO POR DIVISÃO DE CÓDIGO E PROCESSAMENTO POR DECOMPOSIÇÃO DE FATORES PARALELOS.
Authors: Braga Teixeira Francisco Hitalo James , De Aquino Francisco José Alves , Barros Tavares Daniel Alencar 
Published: October 2015

A aplicação de sistemas RFID (Identificação por Rádio Frequência) é uma importante ferramenta para o desenvolvimento e segurança dos processos industriais e afins. No entanto, o uso desta tecnologia em cenários com densas populações de transponders ainda não é trivial e muito menos comum em nosso cotidiano. O processo de singularização em ambientes com múltiplo acesso requer um sistema de controle eficiente e capaz de reduzir interferências, executando a distinção entre os vários sinais transmitidos no canal compartilhado. Neste trabalho, propomos ser válido o conceito de unicidade para um receptor RFID modelado com CDMA (Múltiplo Acesso por Divisão de Código) e o Algoritmo PARAFAC (Decomposição por Fatores Paralelos). Portanto a arquitetura consiste num tratamento de dados multilinear capaz de identificar e processar, simultaneamente, múltiplos transponders RFID a partir de um canal de rádio frequência compartilhado. O artigo apresenta uma introdução sobre os conceitos inerentes à pesquisa, bem como um conjunto de simulações para validar o modelo.
FORMAÇÃO INICIAL DE PROFESSORES DE BIOLOGIA NO IFRN: A CONCEPÇÃO DOS LICENCIANDOS SOBRE O ENSINO/ENSINAR
Authors: Morais João Kaio Cavalcante de , Albino Giovana Gomes 
Published: October 2015

A formação inicial de professores é uma das temáticas mais recorrentes no cenário educacional brasileiro nas últimas décadas, tendo em vista a problemática envolvendo o ensino nas escolas do país. Em meio a esse contexto, a presente pesquisa decorre das inquietações dos autores em entender as concepções que os graduandos do curso de licenciatura plena em Biologia do IFRN campus Macau apresentam sobre o ensino. Para tanto, evidencia como objetivo analisar essas concepções de ensino ressaltadas pelos sessenta e três (63) alunos participantes. Como critério para a interpretação dos dados foi utilizada a técnica de análise de conteúdos (BARDIN, 2011), além do amparo teórico centrado na formação docente que enfatiza o caráter qualitativo da pesquisa. Os resultados mostram que os sujeitos evidenciam duas (2) concepções sobre o ensino: a primeira pautada na perspectiva tradicional, mais amplamente presente nos discursos; e a segunda centrada na ideia de construção do conhecimento, aproximando-se das abordagens mais progressistas. Em vista de tal cenário, os resultados impulsionam a necessidade de que novos contornos possam ser dispensados à referida formação no curso enfatizado, a fim de que a realidade alcance perspectivas ainda mais amplas sobre o significado da ação de ensinar, do papel do docente nesse fazer e, principalmente, do sentido atribuído ao aluno mediante os processos de ensino e de aprendizagem a que o mesmo se vincula.
Metabolitos aislados de raputia heptaphylla y esenbeckia alata (rutaceae) y síntesis de precursores de análogos de alcaloides quinolínicos
Authors: Coy Barrera Carlos A. , Cuca Suárez Luis E. 
Published: October 2015

<p>Abstract. Previous studies on the Esenbeckia alata and Raputia heptaphylla,</p><p>both species belonging to the Rutaceae family, have shown</p><p>important results with respect to their chemistry. These species have</p><p>secondary metabolites (coumarins and alkaloids mainly), which act as</p><p>chemotaxonomic markers. This paper presents, for the first time, the phytochemical</p><p>work and isolated metabolites in these species: four coumarins:</p><p>bergapten, xanthyletin, xanthotoxin, 3-isoprenyl-4-methoxy-coumarin;</p><p>four alkaloids: skinmianine, kokusaginine, dictamnine, and 1-methyl-2-</p><p>methoxy-4-quinolone; two lignans: sesamin and mesodihydroguaiaretic</p><p>acid; two sterols: -sitosterol, stigmasterol; and a pentacyclic triterpene:</p><p>lupeol that have been isolated from leaves of E. alata. Five alkaloids</p><p>7-methoxy-2,2-dimethyl-2,6-dihidro-piran[3,2,c] quinolin-5-one, flindersiamine,</p><p>skinmianine, kokusaginine and dictamnine that have been isolated</p><p>from leaves of R. heptaphylla. Moreover, it presents a new method by</p><p>obtaining quinolone alkaloid analogue precursors trough the condensations</p><p>of Mannich adduct vinylogous and aldehydes followed by radical</p><p>cyclization to obtain products with high regio- and stereoselectivity.</p><p> </p>
The Association Between PD-L1 Expression and the Clinical Outcomes to Vascular Endothelial Growth Factor-Targeted Therapy in Patients With Metastatic Clear Cell Renal Cell Carcinoma
Authors: Shin Su-Jin , Jeon Yoon Kyung , Cho Yong Mee , Lee Jae-Lyun , Chung Doo Hyun , Park Ji Young , Go Heounjeong 
Published: October 2015

Abstract

Background.
Vascular endothelial growth factor pathway (VEGF)-tyrosine kinase inhibitors (TKIs) are used as the first-line treatment for patients with metastatic clear cell renal cell carcinoma (mCCRCC). Recently, programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) blockade emerged as promising therapy for renal cell carcinoma. However, the expression pattern and prognostic implication of programmed death-ligands (PD-Ls) in mCCRCC patients receiving VEGF-TKI remain unclear.

Patients and Methods.
PD-L1 and PD-L2 expression in tumor cells and the quantities of PD-1+ tumor-infiltrating lymphocytes were immunohistochemically evaluated in 91 mCCRCC patients treated with VEGF-TKI, and their associations with VEGF-TKI responsiveness and clinical outcome were analyzed.

Results.
PD-L1 immunopositivity was observed in 17.6% and significantly associated with a high International Society of Urological Pathology grade (p = .031) and sarcomatoid features (p = .014). PD-L2 immunopositivity was observed in 39.6% and was not associated with any of the assessed clinicopathological variables. PD-L1-positive cases showed poor VEGF-TKI responsiveness (p = .012) compared with PD-L1-negative cases. In univariate survival analysis, PD-L1 immunopositivity was significantly associated with shorter overall survival (OS) (p = .037) and progression-free survival (PFS) (p = .043). Multivariate survival analysis revealed that PD-L1 expression was independently associated with poor OS (p = .038) and PFS (p = .013) in addition to tumor necrosis (p = .006; p = .029, respectively) and Memorial Sloan Kettering Cancer Center score (p = .018; p = .032, respectively). PD-L2 expression was neither associated with VEGF-TKI responsiveness nor patients’ outcome.

Conclusion.
PD-L1 expression was significantly related to lack of VEGF-TKI responsiveness and independently associated with shorter survival in mCCRCC patients after VEGF-TKI treatment. PD-L1 may have a predictive and prognostic value for determining the value of VEGF-TKI treatment in patients with mCCRCC.

Implications for Practice:
Vascular endothelial growth factor pathway (VEGF)-tyrosine kinase inhibitors (TKIs) are essential for the treatment of metastatic renal cell carcinoma patients, but the treatment suffers from a lack of predictive markers. This study demonstrates that PD-L1 expression is a predictor for unfavorable response to VEGF-TKI and a prognostic indicator for poor overall survival and progression-free survival in patients with metastatic clear cell renal cell carcinoma receiving VEGF-TKI.
Phase II Trial of Nilotinib in Patients With Metastatic Malignant Melanoma Harboring KIT Gene Aberration: A Multicenter Trial of Korean Cancer Study Group (UN10-06)
Authors: Lee Su Jin , Kim Tae Min , Kim Yu Jung , Jang Kee-Taek , Lee Hyo Jin , Lee Soon Nam , Ahn Mi Sun , Hwang In Gyu , Lee Suee , Lee Moon-Hee , Lee Jeeyun 
Published: October 2015

Abstract

Background.
KIT has been suggested to be a potential therapeutic target for malignant melanoma. We evaluated the antitumor activity and safety of the KIT inhibitor nilotinib in metastatic melanoma patients harboring KIT gene mutations or amplifications.

Methods.
We conducted a phase II multicenter trial of nilotinib in metastatic malignant melanoma with KIT mutations or amplifications. Patients received 400 mg oral nilotinib twice daily. The primary endpoint was response rate, and if seven or more responders were observed from the cumulative 36 patients, nilotinib would be considered worthy of further testing in this study population.

Results.
Between October 2009 and June 2013, 176 patients underwent molecular screening for KIT gene aberrations, and 42 patients harboring KIT gene mutations and/or amplification were enrolled in the study. Overall, 25 (59.5%), 15 (35.7%), and 2 (4.8%) patients had KIT mutations, KIT amplifications, and both KIT mutations and amplification, respectively. Of the 42 enrolled patients, 1 patient achieved complete response, 6 patients achieved partial response, and 17 patients achieved stable disease, resulting in an overall response rate of 16.7% (95% confidence interval [CI]: 5.4%−28.0%) and a disease control rate of 57.1% (95% CI: 42.1%−72.1%). The median duration of response was 34 weeks (range: 5–55 weeks). Of the 7 responders, 6 patients had KIT mutations (exon 11: 5 patients; exon 17: 1 patient), and 1 patient had KIT amplification only.

Conclusion.
Although this study did not meet its primary endpoint of response rate, nilotinib showed durable response in a subset of metastatic melanoma patients with specific KIT mutations.

Implications for Practice:
KIT aberration can be detected in a subset of metastatic melanoma patients. This phase II trial showed that nilotinib demonstrates durable response in a subset of patients with KIT mutations. The safety profile was very tolerable. This study suggests that a KIT inhibitor may benefit a small subset of metastatic melanoma patients with KIT mutations.
EDUCAÇÃO A DISTÂNCIA COMO MODALIDADE INCLUSIVA: E-SIPRIS
Authors: Granetto Julia Cristina , Dal Molin Beatriz Helena , Ludovico Francieli 
Published: October 2015

O presente artigo versa sobre o projeto piloto nomeado e-Sipris, realizado entre a Universidade Estadual do Oeste do Paraná (UNIOESTE) e parcerias. O objetivo do projeto é proporcionar aos apenados de três unidades prisionais, sendo elas: Penitenciária Industrial de Cascavel: PR (PIC), Penitenciária Estadual de Cascavel: PR (PEC) e Penitenciária Federal de Segurança Máxima de Catanduvas: PR, cursos de formação técnica, para que, após o cumprimento de suas penas, estejam capacitados a exercerem uma profissão e (re)integrarem-se na sociedade como cidadãos que agem dentro dos princípios sociais. Essa é uma maneira de garantir a inclusão àqueles que não tiveram acesso à educação. Acredita-se que a formação a distância supera as fronteiras geográficas, sociais e temporais desse processo de ensino-aprendizagem. Este artigo está teoricamente embasado em autores que se dedicam à educação a distância, mais especialmente em Deleuze e o conceito de rizoma, por entender-se que a modalidade educacional em questão tem características hipertextuais, considerando suas especificidades de maneira ampla e vertical.Palavras-chave: Educação a Distância; Sistema prisional; Inclusão. Distance Education as Inclusive Mode: e-SiprisAbstract This paper discusses the pilot project named e-Sipris, conducted by Universidade Estadual do Oeste do Paraná (UNIOESTE) and partnerships. The project goal is to provide to the prisoners of three prison units, namely: Penitenciária Industrial de Cascavel: PR (PIC), Penitenciária Estadual de Cascavel: PR (PEC), e Penitenciária Federal de Segurança Máxima de Catanduvas: PR, technical training courses, so that, after their sentences, they will be able to have a profession and be (re) integrate into the society as citizens who acts accord to the social principles. This is a way to guarantee inclusion of those who had no access to education. It is believed that the distance learning overcomes the geographical, social, and temporal frontiers of the teaching-learning process. This article is theoretically based on authors engaged in distance education, and more especially in Deleuze's concept of rhizome, because it is understood that the educational modality in question has hypertext features considering its specificities in a wide and vertical way.Keywords: Distance Education; Prison system; Inclusion.