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Hawking radiation received at infinity in higher dimensional Reissner-Nordstrom black hole spacetimes

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Chinese Physics C 2021年第8期45卷 182-189页

作者： Kai Lin Wei-Liang Qian Xilong Fan Bin Wang Elcio Abdalla Hubei Subsurface Multi-scale Imaging Key Laboratory Institute of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China Escola de engenharia de Lorena Universidade de Sao Paulo12602-810LorenaSPBrazil Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Faculadade de engenharia de Guaratingueta Universidade Estadual PaulistaGuaratinguetaSPBrazil School of Physics and Technology Wuhan UniversityWuhan 430072China Instituto de Fisica Universidade de Sao PauloSao PauloBrazil

In this study,we investigate the Hawking radiation in higher dimensional Reissner-Nordstrom black holes as received by an observer located at *** frequency-dependent transmission rates,which deform the thermal radiation emitted in the vicinity of the black hole horizon,are evaluated *** addition to those in four-dimensional spacetime,the calculations are extended to higher dimensional Reissner-Nordstrom metrics,and the results are observed to be sensitive to the spacetime dimension to an ***,we observe that the transmission coefficient practically vanishes when the frequency of the emitted particle approaches *** increases with frequency and eventually saturates to a certain *** four-dimensional spacetime,the above result is demonstrated to be mostly independent of the metric's parameter and the orbital quantum number of the particle,when the location of the event horizon,rh,and the product of the charges of the black hole and the particle qQ are ***,for higher-dimensional scenarios,the convergence becomes more ***,the difference between states with different orbital quantum numbers is observed to be more *** the magnitude of the product of charges qQ becomes more significant,the transmission coefficient exceeds *** other words,the resultant spectral flux is amplified,which results in an accelerated process of black hole *** relationship of the calculated outgoing transmission coefficient with existing results on the greybody factor is discussed.

关键词： Hawking radiation Reissner-Nordstrom black hole superradiation

Quality of Electroless Ni-P (Nickel-Phosphorus) Coatings Applied in Oil Production Equipment with Salinity

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Journal of Materials Science and Chemical Engineering 2013年第6期1卷 1-8页

作者： Fernando B. Mainier Maria P. Cindra Fonseca Sérgio S. M. Tavares Juan M. Pardal Escola de engenharia Universidade Federal Fluminense (UFF) Niterói Brazil

The corrosion resistance of nickel-phosphorus (Ni-P) coatings and their mechanical properties in seawater have led inestigations into the development of new technologies and the replacement of some special alloys in equipment used in oil production, such as valves, tubing, sucker rod joints, pumps, riser, manifolds and subsea Christmas trees. These studies began with Brenner and Riddel who developed, in the 1940s, formulations for Ni-P deposition on carbon steel without using an electric current. Joint deposition of nickel and phosphorus on a metallic surface (carbon steel) without applying an external current is accomplished using cathodic reduction with hydrogen (H) from a reducing agent (sodium hypophosphite) and nickel salts. To assure good performance of a Ni-P coating, the deposit quality must be inspected and evaluated during the chemical deposition process or in the end product. The recommended test parameters are: thickness, layer uniformity, hardness, adhesion, porosity, corrosion resistance and chemical composition of the nickel-phosphorus coating. The purpose of this paper was to investigate the Ni-P coating process, to evaluate the b?haviour of Ni-P in a saline environment using aqueous brine (3.5% - 30% sodium chloride by mass) and to present possible defects that could compromise the coating.

关键词： Nickel-Phosphorus (Ni-P) Coatings Corrosion Petroleum Test

DC Plasma Technology Applied to Powder Metallurgy: an Overview

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Plasma Science and Technology 2013年第1期15卷 70-81页

作者： A. N. KLEIN R. P. CARDOSO H. C. PAVANATI C. BINDER A. M. MALISKA G. HAMMES D. FUSAO A. SEEBER S. F. BRUNATTO J. L. R. MUZART LabMat (Materials Laboratory) Departamento de Engenharia Mec~nica Universidade Federal de Santa Catarina (UFSC) 88040-900 FlorianSpolis - SC Brazil Departamento de engenharia Mecanica Universidade Federal do Parana (UFPR) 81531-990 Curitiba- PR Brazil Departamento Academico de Metal-Mecanica Instituto Federal de Santa Catarina (IFSC) 88020-300 Florianopolis - SC Brazil Universidade Tecnologica Federal do Parana (UTFPR) 84016-210 Ponta Grossa - PR Brazil Centro de Ciencia e Tecnologia Universidade de Caxias do Sul 95070-560 Caxias do Sul- RS Brazil

DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

关键词： powder metallurgy DC glow discharge plasma nitriding plasma sintering,plasma-assisted thermal debinding surface alloying

3D-Parallel Simulation of Contaminant in Waste Disposals

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Computer Technology and Application 2011年第3期2卷 213-218页

作者： Alexandre Francisco Bruno Pereira Joss Adilson de Castro Departamento de engenharia Mecdnica Universidade Federal Fluminense Volta Redonda-RJ Brazil

In this work the authors simulate a contaminant transport problem in three dimensions that takes place in the soil of waste disposals. Such problem is modeled by a diffusion-dominated equation. The solution of this equation is addressed by using mixed finite element method for the spatial discretization of the equation. The resulting linear algebraic system is handled by an iterative domain decomposition procedure. This procedure is naturally parallelizable, and permits to implement computational codes in distributed memory machines in order to save on CPU time. Numerical results of the serial and parallel codes were compared with experimental results, and their performance measures were evaluated. The results indicate that the parallelizable procedure is an efficient tool for performing simulations of the problem.

关键词： Parallelizable procedure mixed finite elements transport problem.

Assessing Cleaner Energy Alternatives for Bus Transit in Rio de Janeiro:A Life Cycle Inventory Analysis

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Journal of Environmental Protection 2015年第11期6卷 1197-1218页

作者： Marcio de Almeida D’Agosto Cintia Machado de Oliveira Fabiana do Couto Assumpcao Ana Carolina Peixoto Deveza Programa de engenharia de Transportes Instituto Alberto Luiz Coimbra de Pos-Graduacao e Pesquisa em Engenharia(COPPE)Universidade Federal do Rio de JaneiroRio de JaneiroBrazil Centro Federal de Educacao Tecnologica Celso Suckow da Fonseca Engenharia Industrial MecanicaUnedItaguaiBrazil

From 2003 to 2009 in Brazilian municipalities of over 60,000 inhabitants, buses accounted for more than 25% of urban trips. This trend is not expected to change in the medium term. Worldwide, buses rely on petroleum diesel as fuel. In Brazil, alternative fuels such as biodiesel, natural gas and ethanol are available and the choice among them should depend on the assessment of the entire life cycle of such fuels. This paper uses a Life Cycle Inventory, which is essential to the implementation of a Life Cycle Assessment, to assess six energy alternatives: petroleum diesel, biodiesel, petroleum diesel with 5% of biodiesel, compressed natural gas, additivated hydrous ethanol and dual-fuel system composed by petroleum diesel with 5% of biodiesel and compressed natural gas. In saving total energy consumption, pure petroleum diesel or mixed with 5% biodiesel and dual-fuel systems stand out, in that order. If renewable energy use and net carbon dioxide emissions reduction are the goals, ethanol and biodiesel should be given preference. The addition of 5% of biodiesel in petroleum diesel increases the share of renewable energy in the supply chain of petroleum diesel by 47.5% with an increase of 0.58% in total energy consumption and a reduction of 3.8% in net CO2 emissions during the life cycle. In the case of biodiesel, the addition of 5% of biodiesel in petroleum diesel increases the share of renewable energy in the supply chain by 51.15% with an increase of 0.03% in the total energy consumption and a decrease of 7% in net CO2 emissions in the life cycle. The use of 5% of biodiesel in petroleum diesel does not significantly affect the use of renewable energy (+0.69%) or total energy consumption (+0.04%) in ethanol supply chain, which already shows a great use of renewable energy input. However, a decrease of 9.29% in the net CO2 emissions in the supply chain occurs, which reaches 5.28% in the life cycle.

关键词： Renewable Energy Total Energy Public Transportation Biofuels Life Cycle

A New Approach to the Ordered Classification of Critical Factors in the Degradation Processes of River Basins

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Journal of Environmental Science and Engineering(B) 2019年第6期8卷 258-267页

作者： Antonio Cunha Nunes Fernando B.Mainier Robson Rosa Branco Carlos Alberto Pereira Soares Escola de engenharia Universidade Federal FluminenseNiteroiRio de JaneiroBrazil

The aim of this paper is to present through information collected via qualitative analysis in order to provide an alternative perspective to classify critical factors and their correlations in the processes of degradation of river basins in countries in development in an ordered *** study was started with a bibliographical review for gathering relevant information about the main factors,which was submitted to specialists and related professionals via survey developed in a format of answers on Likert scale,with the analyses of data from the respondents as well as their contribution within sample assembly exploratory factorial analysis and the charge factor item from the questionnaire with usage of polychoric correlation matrix with which it is proposed to establish the ordering of the factors relevance as well as their correlations through parametric statistical analysis with the usage of a generalized model of partial credit which belongs to the family of the models for polyatomic gradual answers to the item response theory(IRT)and the applying of cluster analysis(ICLUST)with the usage of both alpha and omega coefficient for the estimation of the variables group,with the R *** a result,the present study aims to establish a comprehension of the main factors for the ordering of the actions and attention of public and private sectors towards the preservation of urban river basins.

关键词： Degradation river basins critical factors society an environment psychometry

Tunnel geometry of the subterranean termite Reticulitermes grassei （Isoptera： Rhinotermitidae）in response to sand bulk density and the presence of food

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Insect Science 2007年第6期14卷 511-518页

作者： TANIA NOBRE LINA NUNES DAVID E. BIGNELL Laboratorio Nacional de engenharia Civil Nucleo de Estruturas de Madeira Lisboa Portugal Queen Mary University of London School of Biological and Chemical Sciences London UK Institute of Tropical Biology and Conservation Universiti Malaysia Sabah Kota Kinabalu Sabah Malaysia

The cryptic habits of subterranean termites restricts detailed analysis of their foraging patterns in situ, but the process is evidently dominated by tunnel constructions connecting the nest with woody resources discovered within the territory of each colony. In this study, tunnel formation and orientation were studied experimentally in the termite Reticulitermes grassei （Clement）, using 2-dimensional laboratory foraging arenas con- taining fine sand as the substratum. The building of exploratory tunnels over a 10-day period and the geometry of the resulting network are described. Fractal analysis showed that tunnel geometry had a fractal dimension, regardless of the total length tunnelled whether foragers encountered the food source or not. The bulk density of the sand in the arenas affected the distances tunnelled, with higher density reducing construction, but did not affect tunnel geometry. Tunnels were not discernibly orientated with respect to the positioning of the food source, even in a situation where termites had failed to find the food source at a distance of less than 50 mm, suggesting that volatiles from wood are not attractants.

关键词： foraging gallery fractal analysis Reticulitermes grassei search pattern,subterranean termites tunnel geometry

Proposal of a fireproof design code for dwellings against the action of wildland fires

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Resilient Cities and Structures 2023年第3期2卷 104-119页

作者： M.R.T.Arruda A.R.A.Bicelli P.Cantor E.B.Assis F.Branco CERIS Instituto Superior TécnicoUniversidade de LisboaPortugal Escola de engenharia de São Carlos Universidade de São PauloBrazil Instituto Superior Técnico Universidade de LisboaPortugal

This study proposes a concept for the development of a fireproof design code for the verification of dwellings susceptible to wildfire *** are currently structural codes for the design of buildings when subjected to indoor fires,outside fires that grow on the facade of buildings,and even fires in an accident situation due to ignitions with hydrocarbons or transportation *** of these security verification specifications are described in EC1:*** current regulation in Portugal uses safety criteria and risk categories that are for indoor fires,therefore is very conservative and may not present an economic fireproof design against the action of *** aim of this work is a straight verification based on natural temperature characteristic curves that simulate wildfire heat flow by convection,radiation,and the deposits of firebrands.

关键词： Structural safety verification Wildfires in dwellings Nominal fires vs natural fires Fireproof construction guidelines

Onset of chaotic gravitational lensing in non-Kerr rotating black holes with quadrupole mass moment

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Chinese Physics C 2023年第8期47卷 122-135页

作者：吴文浩张承勇邵成刚钱卫良 MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum PhysicsPGMFand School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Department of Physics and Siyuan Laboratory Jinan UniversityGuangzhou 510632China Escola de engenharia de Lorena Universidade de São Paulo12602-810LorenaSPBrazil Faculdade de engenharia de Guaratinguetá Universidade Estadual Paulista12516-410GuaratinguetáSPBrazil Center for Gravitation and Cosmology School of Physical Science and TechnologyYangzhou UniversityYangzhou 225002China

In the electromagnetic channel,chaotic gravitational lensing is a peculiar phenomenon in strong gravita-tional *** this study,we analyze the properties and emergence of chaotic gravitational lensing in the Manko-Novikov black hole *** to better understand the underlying physics,we elaborate on the boundaries of the accessible region through analyses of the contours of the effective *** latter is associated with the two roots of a quadratic *** particular,we explore its interplay with an ergoregion,which leads to specific features of the effective potentials,such as the emergence of a cuspy edge and the formation of a pocket,which serve as static constraints on the ***,we investigate the properties of the radial and angular accelerations at the turning points in photon *** accelerations are further examined and may provide kinematic constraints on the geodesics,as argued *** is concluded that the onset of the chaotic lensing is significantly related to both con-straints;as a result,an arbitrary slight deviation in the incident photon is significantly amplified during evolution through an extensive period,demonstrating the complexity in the highly nonlinear deterministic gravitational system.

关键词： black hole shadow chaos black hole image