bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling the Mechanical Behavior of Polymer-Based Nanocomposites
Authors: Correia Alexandre , Valashani S. Mohsen , Pires Francisco , Simões Ricardo
Published: November 2012

Molecular dynamics simulations were employed to analyze the mechanical properties of polymer-based nanocomposites with varying nanofiber network parameters. The study was focused on nanofiber aspect ratio, concentration and initial orientation. The reinforcing phase affects the behavior of the polymeric nanocomposite. Simulations have shown that the fiber concentration has a significant effect on the properties, with higher loadings resulting in higher stress levels and higher stiffness, matching the general behavior from experimental knowledge in this field. The results also indicate that, within the studied range, the observed effect of the aspect ratio and initial orientation is smaller than that of the concentration, and that these two parameters are interrelated.
Numerical Study of Mechanical Behaviour of Heterogeneous Materials
Authors: Branco Rui M. , Prates Pedro , Oliveira Marta C. , Sakharova Nataliya A. , Fernandes José Valdemar
Published: November 2012

The mechanical behaviour of heterogeneous specimens under uniaxial tensile test is studied using finite element analysis. The difference between mechanical properties of adjacent regions in the heterogeneous specimen creates constraints which alter the strain path relatively to pure tension. A methodology for determining the local stress-strain curves is proposed and successfully tested numerically on the heterogeneous specimen composed by two materials with dissimilar plastic properties. This methodology has recourse to the same type of variables which are usually obtained experimentally with the digital image correlation technique.
Development of a Process for Copper Recovering from Galvanic Sludges
Authors: Vilarinho Cândida , Castro Fernando , Carneiro Filipa , Ribeiro André
Published: November 2012

Galvanic coating processes are based on metal plating baths and are responsible for the production of large amounts of wastewaters. Subsequent physical-chemical treatment of the wastewaters generates solid wastes called galvanic sludges. These sludges have a hazardous character and are often disposed, mainly on landfills, without any economical or environmental benefits. The development of alternatives and viable ways to reduce the environmental impact and recover the valuable metals contained in those sludges such as copper, chromium, nickel or zinc, which content might reach 30% (wt.%, dry weight) are of utmost importance. The present work has been developed in the aim of the project VALMETAIS and proposes a hydrometallurgical process for copper recovery from galvanic sludges produced by Ni/Cr plating plants. This procedure has been developed on laboratory scale and is based on leaching of sludges in sulphuric acid solution followed by copper cementation step, using iron scrap as a precipitating agent. The sludge has been characterized for its chemical and physical properties. Chemical analysis showed a copper concentration of more than 10% (dry base). Preliminary leaching tests in both sulphuric acid and ammoniacal media were performed in order to determine the best operating conditions for this step of the process and to assure the best metal recovery conditions in subsequent separation methods. Sulphuric acid yielded much higher metal ion dissolution when compared with ammoniacal leaching. Optimal experimental leaching parameters were defined as follows: sulphuric acid solution 100 g/l, a solid to liquid ratio of 1:10, stirring speed of 400 rpm at room temperature and under atmospheric pressure. It was found that metals dissolution was almost complete in 30 minutes of reaction time. Extraction rates of 99% for Cu and Ni were obtained under the leaching conditions above mentioned. The solid residue separated from the leaching solution is mostly constituted by gypsum (CaSO4), and presents a metal content below 1%. The subsequent extraction of cooper from the obtained solution is achieved by a cementation step with iron scrap. Copper precipitation was performed at a pH of 2 which was achieved through adding new sludge to the filtered leaching solution. Such pH level led to insignificant precipitation of other metals present in the leaching solution, namely chromium. The recovery rate of copper is about 90% and the purity grade of the resulting copper cement enables its application as a commercial product.
Evaluation of the Energetic Valorization Potential of Polymeric and Textile Industrial Wastes
Authors: Sousa Célia , Castro Fernando , Vilarinho Cândida , Soares Delfim
Published: November 2012

Among the solid wastes produced by textile industry, there is a significant amount of wastes with energetic value and which are usually sent to controlled landfills, without any recovery. This traditional route corresponds to high economical and environmental costs, since wastes can be used as a source of energy and/or materials. With the recycling route strongly restricted due to the presence of mixtures of different types of polymeric compounds, some of them not biodegradable, the study of the feasibility of energy recovery from such wastes is of upmost importance and the aim of the present work. Most of the wastes are valuable resources that can be used as raw materials or as an energy source to produce heat or electricity. In this work the potentiality of energy recovery from solid wastes of some of the Vale do Ave textile units was investigated. For that purpose, wastes have been characterized for their weight loss at 105°C, calorific value and ashes content (after burning out at 850°C). The chemical composition of the ashes was determined by X-Ray fluorescence spectrometry. DSC-TGA tests were performed in two different atmospheres, air and argon, in order to evaluate the thermal behavior of the studied wastes. The characterized wastes showed calorific values not negligible, varying from 3500 to10400 kcal/kg (at dry base), similar to the results obtained by others authors and comparable to solid materials which are traditionally considered as fuels (sugar cane, lignite, etc). A weight loss at (105°C) lower than 6.5% and a maximum ashes content of 15% was achieved. However, some ashes present high contents of heavy metals, which can drives to environmental concerns. By the analysis of the thermal profiles it was found that wastes decomposition takes place at low temperatures (< 600°C) resulting in a small amount of the final solid fraction. Concerning the obtained results, the solid wastes collected from different textile units show high potential for energy recovery.
Soda and Aluminum Recovery from Spent Etching Baths by Aqueous Precipitation
Authors: Berto Andrea , Nogueira Carlos A. , Margarido Fernanda
Published: November 2012

The aluminum anodising industry is an important industrial sector that produces great amounts of polluted effluents, which after treatment generate sludge. This fact brings environmental and economical concerns to the companies. Best way to deal with the problem, according to the “prevention strategy” set by the European Directive on Integrated Pollution Prevention and Control, is to implement preventive techniques and technologies to optimise the use of resources and minimise losses, and in turn waste. Among the operations of an anodising line, the etching/satinising stage is responsible for the production of a huge quantity of wastewater neutralisation sludge and for the wrong use of caustic soda. “Caustic etch recovery” technology is claimed to drastically reduce the generation of neutralisation sludge and the purchasing of fresh caustic soda by regenerating the exhausted etching/satinising solution, through an aqueous precipitation reaction. This paper presents the capability of the technology to effectively regenerate the exhausted caustic solution, and investigated the parameters with major effect on the process yield, in order to optimise it. It was demonstrated that the technology effectively recovers the solution, increases its soda content and diminishes the dissolved aluminum content by precipitation. Moreover the conditions that optimise the process are simple and inexpensive. After treatment the solution present the properties to be recycled in the etching/satinising operation.
Waste Fiber Reinforced Composite Materials: Production and Mechanical Properties
Authors: Velosa João , Fangueiro Raul , Martins Nelson , Fernandes M. , Soutinho Filipe
Published: November 2012

Today, the cost, excellence and availability of raw materials are of principal importance. Due to environmental concerns, a very large number of companies are currently developing manufacturing processes using alternative materials for their crop and in search of new markets for the sub-products of their first-line production. Textile industry is an example of the reality that the industry is living these days. With a significant production of waste fibrous materials, textile companies are now looking for applications where waste materials could be an added-value material. Composites reinforced by fibres are being considered for several uses when high performance is essential. The corrosion resistance, potentially high overall durability, light weight, tailor ability and high specific performance attributes enable the use of composite materials in areas in which the use of conventional material might be constrain due to durability, weight or lack of design flexibility. This paper describes the work that is being done at University of Minho concerning the development of waste fibers reinforced composite materials. Different waste fibers reinforced composite materials have been produced varying the density and the variation in ratio of resin and waste fibers. Waste fibers have been collected within some textile companies and processed in order to individualize the fibers and to allow subsequent processing. Composite panels have been produced by compression moulding technique, through the application of heat and pressure. Panel thicknesses of 5 mm using resin aminoplastic for urea-formaldehyde have been produced. Materials thus obtained have been tested in tensile, bending, compression test. The results obtained are presented and discussed.
An Analysis of the Physical Properties of Multicomponent Alloy on the Simulation Solidification by Phase-Field Model
Authors: Salvino Ingrid M. , Jácome Paulo A.D. , Ferreira Alexandre F. , Ferreira Ivaldo L.
Published: November 2012

A phase-field model is proposed for the simulation of microstructure and solute concentration during the solidification of Fe-C-P-Mn quaternary alloys. In this paper, a study is presented to analyze both the effects of partition coefficient and solute diffusivity on the microstructural evolution during solidification simulation. Partition coefficient and diffusivity are very important from a practical standpoint, because both parameters exert a strong influence on the dendrite morphology. Additionally, the proposed model is applied for quaternary alloys to the analysis of the time-dependent solidified fraction. Simulations permit to conclude that the solidified fraction is proportional to the square root of time, as expected for any diffusion-controlled growth process. Phase-field simulations on non-isothermal dendrite growth are also examined. Two-dimensional simulation results exhibit different dendrites in multicomponent alloys for different solute concentrations. Changes in the carbon concentration seem to affect the dendrite morphology, due to its higher concentration and its lower equilibrium partition coefficient. Changes in the phosphorus concentration affect the dendrite morphology and the interface velocity, when its content is increased from 10-3mol%P. Higher manganese content slows down the solidification kinetic, while the dendrite morphology remains unchanged.
Application of Impedance Spectroscopy for Bi1−xNdxFeO3 Ceramics Characterization
Authors: Wodecka-Dus Beata , Dzik Jolanta , Bernard Henryk , Osinska Katarzyna , Lisińska-Czekaj Agata , Czekaj Dionizy
Published: November 2012

In the present paper the synthesis conditions for fabrication of Bi1−xNdxFeO3 ceramics are reported. The single phase polycrystalline samples of Bi1−xNdxFeO3 were prepared by standard solid state reaction method from the mixture of oxides viz.: Bi2O3, Fe2O3 and Nd2O3. The samples were characterized by impedance spectroscopy in the frequency range 10Hz – 1MHz at room temperature.
Effect of Inorganic Content on the Performance of Anticorrosive Hybrid Sol-Gel Coated EN AW-6063 Alloy
Authors: Fontinha Rute I. , Salta Manuela M. , Zheludkevich Mikhail L. , Ferreira Mário G.S.
Published: November 2012

The organic-inorganic hybrid sol-gel films have been reported as an effective anti-corrosion and environmentally friendly alternative to Cr(VI) pre-treatment for aluminium alloys. The sol-gel process used to obtain these coatings allows the variation of the different synthesis parameters to achieve coatings with optimized properties. In this work, hybrid films with different Zr/Si ratios were synthesized from glycidoxypropyltrimethoxysilane (GPTMS) and zirconium n-propoxide (TPOZ) precursors. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the corrosion behaviour of coated aluminium specimens in 0.5 M NaCl solution. The morphology and chemical structure of the hybrid coatings prepared were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), Fourier Transformed Infrared Spectroscopy (FTIR) and Thermo Gravimetric Analysis (TGA). It was found that increasing Zr/Si ratio leads to a more cross linked inorganic network, resulting in higher initial coatings resistance, but may turn coatings more hydrophilic, prone to rapid degradation in water, due to a less connected organic network. Consequently, the best anticorrosive performance derives from the balance between the two opposite trends and it was achieved with Zr/Si molar ratio of 0.25.
Factors Affecting the Metal Recovery Yield during Induction Melting of Aluminium Swarf
Authors: Puga Hélder , Barbosa Joaquim , Ribeiro Carlos Silva
Published: November 2012

Machining operations of cast parts usually generate considerable amounts of waste in the form of chips (usually 3–5% of the casting weight). Traditionally, swarf is sold to scrapers and remelters, but this option is quite expensive because the selling price is roughly 30% of the acquisition price of the commercial 2nd melt raw material. For most aluminium foundries that incorporate machining operations in their products, reusing aluminium chips as raw material for the melting stocks is perhaps the best option as waste management policy in what concerns to economical and technical aspects. Nevertheless, aluminium swarf is a low density product (0.25 kg/dm3) and is usually covered by a thin film of aluminium oxide and machining fluid. Melting such a product without suitable previous preparation leads to very low metal recovery rates, high energy consumption, gases and smoke generation and very low quality of the final product. During the last years, the authors have developed a high efficient and environmentally friend aluminium swarf recycling technique, using direct incorporation in aluminium melts. The influence of processing parameters, namely melt temperature and holding time, melting atmosphere, swarf briquetting pressure and melting charge composition in the metal recovery yield and dross generation was studied and characterized, and the optimal processing parameters were established. The microstructure of the final product obtained in those conditions was evaluated and is also presented. It is shown that the recycling efficiency depends on the swarf conditioning, the melting technique and the melt treatment methodology. Swarf moisture reduction, induction melting under protective atmosphere and a specially developed degassing technique were found the most important factors influencing the recycling process. By using the developed technique, cast ingots with microstructure and sanity similar to commercially available AlSi12Cu1 2nd melt raw material were successfully obtained with minimal dross formation and metal recovery rates around 90%, without using traditional salts and fluxes.
Process Stability Evaluation of Manual Metal Arc Welding Using Digital Signals
Authors: Slazak B. , Slania J. , Węgrzyn T. , Silva Abílio P.
Published: November 2012

The experimental investigation has been carried out to evaluate process stability for two rutile types of electrode supplied with two types of DC power sources: traditional 3 phase thyristor and inverter type. Initially to understand the maximum range of outcomes high quality and defective electrodes, with lower arc stability, were selected for both. During welding tests current and voltage signals were recorded separately with the aid of A/D converter and 5 kHz of sampling frequency. On the basis of digital signals obtained from each electrode type and power sources, a number of statistical indicators have been computed. Furthermore voltage and current histograms have been determined (defined as a density distribution of welding arc voltage and current values). Statistical indicators of voltage signals have proved to be more useful for process stability evaluation, particularly mean voltage (Uśr) and histograms as well as voltage coefficient of variation (KvU).
The Influence of Boron on Structural Properties of Martensitic 8-10%Cr-Steels
Authors: Materna-Morris Edeltraud , Klimenkov Michael , Möslang Anton
Published: November 2012

Four alloys on the basis of 8-10% CrWVTa steel were melted to study the influence of boron on the structure and precipitation behavior. Boron contents in the alloys amounted to 0.0083 and 0.1 wt.%, respectively. One batch was nearly free of boron. The individual alloys were examined metallographically and characterized in the initial state and after aging treatments up to 800 °C. It was found that the grains of boron-containing alloys were coarsened when the alloys were subjected to tempering. At the same time, the precipitate content was reduced. The different phases of precipitates were analyzed as primary carbides with tantalum and tungsten, and due to the higher content of boron BN, B(C, N), and (Fe, Cr)2B. M23C6 was developed in all alloys after the heat treatment.
Microwave Absorbing Nanocomposites Composed with and without Polyaniline by Use as Radar Absorbing Structure
Authors: de Castro Folgueras Luiza , Rezende Mirabel Cerqueira
Published: November 2012

In the past decade, new materials have been developed based on the physical and chemical properties of carbon nanotubes. The combination of polyaniline with multiwall carbon nanotubes results in a new functional material with advantageous electromagnetic properties. The objective of this study was to produce a radar absorbing structure consisting of glass fiber woven fabric impregnated with a formulation containing carbon nanotubes, polyurethane resin, with or without polyaniline. A different formulation was used for each woven sheet (multilayer structure). The electromagnetic properties of these nanocomposite materials were characterized by reflectivity measurements using Naval Research Laboratory arch method (frequency range, 8 to 12 GHz). The attenuation of both sides of each nanocomposite material was also measured and compared. The attenuation of electromagnetic energy was as high as 70 %, approximately, indicating that these materials can be used as microwave absorbers.
Assessment of Injection Moulded Parts of PP/Nanoclay Produced with Hybrid Moulds
Authors: Neves Alessandra F. , Salmoria Gean V. , Ahrens Carlos H. , Pouzada António Sergio , Silva Mariana A.
Published: November 2012

The concept of hybrid mould combines the conventional techniques of mould manufacturing and Rapid Prototyping and Rapid Tooling, resorting to non-conventional materials for producing moulding blocks, e. g., epoxy resin composites. Composites based on an epoxy system with 15% weight fraction of short steel fibres (SSF) were considered adequate for improving the performance of moulding blocks. The epoxy/short steel fibre composite moulding blocks were produced by vacuum casting in silicone moulds. Polypropylene (PP) was mixed with a commercial PP masterbatch with 50% of nanoclay and injected in a hybrid mould under various processing conditions. These were chosen from a central composite design with 15 experiments. The moulding microstructure was assessed by polarized light microscopy and differential scanning calorimetry. The skin-core morphology was observed and suggested that the low thermal conductivity of the epoxy composite produces a thinner skin when compared to all-steel moulds. The nanoclay concentration was the variable with the most significant effect on skin thickness and crystallinity. The addition of 1 wt% nanoclay under certain processing conditions favours the formation of β-form spherulites and the increase of crystallinity.
Theoretical signposts for tracing spirituality within the fluid decision-making of a mobile virtual reality
Authors: Van den Berg Jan-Albert
Published: November 2012

In the context of the interconnected world of the information age, and demarcated by a virtual existence through the use of the Internet, decision-making has become even more dynamic. In an evolving era of virtuality, with special emphasis on the increasing role of mobile communication technology, it is indicated that decision-making has become fluid. As part of the phenomenon of fluid decision-making, not only is the evolutionary character of virtual connectivity acknowledged, but the ever-increasing and important role of mobile platforms is also emphasised. In a hermeneutical practical theology of lived spirituality, focusing on the praxis of everyday living, the possible role of spirituality in informing the fluid decision-making processes in a mobile virtual world was traced. A qualitatively inspired analysis, using data collected from various virtual forums, was proposed. In the description of these contours, special emphasis was placed on narrative-inspired biographical accents. The research made a contribution in terms of possible new articulations of the language of faith as embodied in fluid decision-making in a mobile virtual reality.
Could the ‘evolution’ from biology to life sciences prevent ‘extinction’ of the subject field?
Authors: Ferreira Johanna G.
Published: November 2012

In this article the change of the school subject ‘biology’ to ‘life sciences’ as well as the associatedand expected implications of this change are discussed. The question arises whether the intended change is significant enough and whether it would address the decreasing interest in the life sciences at tertiary level. The changes in the new curricula make the content more relevant to learners and the community itself, but certain selected issues are not addressed. Suggestions are made to amend the curriculum and to adapt teaching methods to facilitate the development of the necessary skills in learners.
ANALIZA KONCENTRACIJE RADONA U SEIZMIČKI AKTIVNIM ZONAMA TUZLANSKE REGIJE
Authors: Spona Uzeir
Published: November 2012

U ovom radu prikazani su rezultati mjerenja koncentracije aktivnosti radona u seizmički aktivnim zonama Tuzlanske regije. Od velikog broja metoda za mjerenje koncentracije aktivnosti radona izabrana je metoda trag detektora tipa CR39, koji su pogodni za dugotrajna mjerenja radona, od nekoliko dana do više mjeseci, pri čemu dobijeni rezultati predstavljaju srednje koncentracije radona na datoj lokaciji za određeni interval mjerenja. Dat je i prikaz procedure rada sa trag detektorima prilikom mjerenja koncentracije aktivnosti radona Mjerenja su vršena od 26.11.2009. do 07.06.2010. godine. Eksponirani detektori su obrađeni na RadoSys sistemu u Laboratoriji za detekciju, dozimetriju i zaštitu od jonizujućeg zračenja Prirodno-matematičkog fakulteta Univerziteta u Tuzli.
DEFINISANJE MAKSIMALNOG KORAKA NAPREDOVANJA MEHANIZOVANE HIDRAULIČNE PODGRADE (MHP) ZA USLOVE RUDNIKA „STRMOSTEN“
Authors: Miljanović Jovo , Kokerić Slobodan , Guberinić Rade , Živojinović Miljanović Ivana , Kovačević Žarko1
Published: November 2012

Interakcija jamskog masiva i mehanizovane hidraulične podgrade, predstavlja jedan od primarnih uslova uspešne primene MHP pri otkopavanju uglja posebno kada se radi o složenim uslovima eksploatacije ugljenih slojeva. Izbor optimalne nosivosti podgrade kao i tipa i konstrukcije je još uvek jedno od najvažnijih pitanja a pouzdan izbor je moguće izvršiti samo na bazi osnovnog poznavanja geomehaničkih karakteristika radne sredine, kao i karaktristika mehanizovane hidraulične podgrade. Obzirom da fizičko- mehanička svojstva stenskog masiva direktno utiču kako na izbor tipa i konstrukcije mehanizovane hidraulične podgade tako i na veličinu koraka napredovanja MHP neophodno je izvršiti modeliranje stenskog masiva.
Effective Pre-school Management as the Foundation of Quality Education A Case Study of Bangladesh
Authors: Fatima Khandaker Ummul Khairun , Nik Abdul Rahman Nik Suryani
Published: November 2012

Pre-school gives an orientation to a child before it goes to a formal school. Studies also suggest that enrolment in pre-school education can enhance children’s cognitive skills, literacy and social skills, necessary for success as well as promoting school achievement in the elementary grades retention and increase levels of school attainment (Schweinhart et. al., 1993; Campbell & Ramey, 1994; Reynolds et. al.,1996; Ou, 2003. There is scarcity of quality preschools in Bangladesh though there are a large number of preschools all over the country. In the absence of clear government policy and guidelines, these schools are conducted as private properties by individuals and groups who run these on a commercial basis and fail to provide quality education. This study aims at investigating the obstacles to effective management of preschools and the development of a model of establishing a large number of preschools at the initiative of the private sector under the patronage of the government. Data collection and the subsequent analyses were guided by qualitative research methods against the theoretical framework of Leaver’s (2011) “experiential education”. From this research 4 themes were derived, namely (1) Quality management (2) Quality teacher (3) Quality Parent Teacher Association (PTA) and (4 Quality leadership of the Principal.   Keywords - Pre-school, quality education, cognitive skills, social skills, effective management, commercial basis.
Peixes do trecho superior do rio Paranaíba durante a estação chuvosa. 10.7902/ecb.v3i1.1
Authors: Silva Willian Lopes , Penteado Pierre Rafael , Kavalco Karine Frehner , Pazza Rubens
Published: November 2012

A ictiofauna da Bacia do Rio Paranaíba é muito rica, com registros de 114 espécies, distribuídas em nove ordens. Por outro lado, ainda é pouco estudada, principalmente em seu trecho superior. Este trabalho trata-se de um levantamento parcial que tem como objetivo caracterizar a diversidade ictiofaunística do primeiro trecho da bacia do alto Paranaíba durante a estação chuvosa. Este primeiro trecho do rio Paranaíba é caracterizado pela forte presença agrícola. Três pontos de coleta foram amostrados desde região próxima à nascente no município de Rio Paranaíba, até o município de Patos de Minas. Foram utilizadas amostragens direta e aleatória. Em amostragem direta, foi utilizado um conjunto de 10 redes de espera por cerca de 10h e no método de amostragem aleatório utilizaram-se tarrafas, redes de arrasto e peneiras. Foram capturados 78 espécimes distribuídos em oito famílias, 10 gêneros e 12 espécies. As famílias com maior número de espécies foram Characidae (Characiformes) e Heptapteridae (Siluriformes).
Localização física dos genes ribossomais 5S e 18S em "Ancistrus" sp. da bacia dos rios costeiros no Rio de Janeiro (Loricariidae: Ancistrini). DOI: 10.7902/ecb.v3i1.13
Authors: Rocha Reis Dinaíza Abadia , Brandão Karina De Oliveira , Almeida-Toledo Lurdes Foresti de , Pazza Rubens , Kavalco Karine Frehner
Published: November 2012

Ancistrus é considerado um gênero diversificado na tribo Ancistrini e corresponde a peixes conhecidos popularmente por “cascudos”.  Os DNAs ribossômicos mais estudados são o rDNA 18S, que participa da formação de Regiões Organizadoras de Nucléolo,  e o rDNA 5S. O objetivo deste trabalho é determinar a localização física dos sítios de DNAr 18S e 5S em Ancistrus sp. da região de Angra dos Reis-RJ, bacia dos rios Costeiros. Através de Hibridação Fluorescente in situ (FISH) foram identificados 4 sítios de rDNA 18S localizados em quatro diferentes cromossomos (pares 3 e 14) e 2 sítios de rDNA 5S, localizados em dois cromossomos (par 13), todos em região terminal. Os resultados deste estudo podem ser aplicados em abordagens conservacionistas, podendo auxiliar no entendimento da evolução cromossômica desta espécie e da tribo Ancistrini.
Icitiofauna do rio Lourenço Velho, afluente do rio Grande: pequena diversidade, grande importância para a conservação de uma espécie ameaçada. 10.7902/ecb.v3i1.3
Authors: Belei Frederico , Sampaio Wagner Martins Santana
Published: November 2012

O rio Grande é um importante rio para o alto rio Paraná, um dos principais rios do trecho do alto rio Paraná é o rio Lourenço Velho que tem destaque por apresentar a PCH mais antiga de Minas Gerais. A bacia do rio Lourenço Velho foi inventariada buscando revelar a diversidade da ictiofauna e levantar as principais espécies da região. Foram coletados peixes em duas regiões do rio Lourenço Velho. Estes peixes estão distribuídos em 10 espécies. Dentre estas espécies, a mais abundante foi a pirapitinga Brycon nattereri, que é amplamente conhecida por ser uma espécie ameaçada bastante sensível a alterações ambientais. Provavelmente esta espécie apresenta a abundância do presente estudo devido ao isolamento dos grandes carnívoros provocados pela barreira geográfica da PCH Luis Dias.
Self‐Assembly of Nanostructured, Complex, Multication Films via Spontaneous Phase Separation and Strain‐Driven Ordering
Authors: Wee Sung Hun , Gao Yanfei , Zuev Yuri L. , More Karren L. , Meng Jianyong , Zhong Jianxin , Stocks George M. , Goyal Amit
Published: November 2012

Spontaneous self‐assembly of a multication nanophase in another multication matrix phase is a promising bottom‐up approach to fabricate novel, nanocomposite structures for a range of applications. In an effort to understand the mechanisms for such self‐assembly, complimentary experimental and theoretical studies are reported to first understand and then control or guide the self‐assembly of insulating BaZrO3 (BZO) nanodots within REBa2Cu3O7–δ (RE = rare earth elements including Y, REBCO) superconducting films. The strain field developed around BZO nanodots embedded in the REBCO matrix is a key driving force dictating the self‐assembly of BZO nanodots along REBCO c‐axis. The size selection and spatial ordering of BZO self‐assembly are simulated using thermodynamic and kinetic models. The BZO self‐assembly is controllable by tuning the interphase strain field. REBCO superconducting films with BZO defect arrays self‐assembled to align in both vertical (REBCO c‐axis) and horizontal (REBCO ab‐planes) directions result in the maximized pinning and Jc performance for all field angles with smaller angular Jc anisotropy. The work has broad implications for the fabrication of controlled self‐assembled nanostructures for a range of applications via strain‐tuning.
Why Do Companies Not Produce Sustainability Reports?
Authors: Stubbs Wendy , Higgins Colin , Milne Markus
Published: November 2012

Sustainability reporting emerged on the corporate scene nearly 30 years ago as a key mechanism through which business organisations would manage a transition to a new business landscape dominated by greater concern and consciousness about sustainability. While it has become something of a feature on the corporate agenda in some parts of the world, the majority of business organisations do not undertake this type of reporting. This paper explores why 23 of Australia's top 200 companies do not undertake sustainability reporting. The study is situated in the context of a considerable literature that promised numerous benefits to be derived from this type of reporting. The paper uncovers various social and organisational factors that raise some new questions about legitimacy theory, corporate accountability and the spread and uptake of this organisational practice. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Automatic tracking of labeled red blood cells in microchannels
Authors: Pinho Diana , Lima Rui , Pereira Ana I. , Gayubo Fernando
Published: November 2012

The current study proposes an automatic method for the segmentation and tracking of red blood cells flowing through a 100‐ μm glass capillary. The original images were obtained by means of a confocal system and then processed in MATLAB using the Image Processing Toolbox. The measurements obtained with the proposed automatic method were compared with the results determined by a manual tracking method. The comparison was performed by using both linear regressions and Bland–Altman analysis. The results have shown a good agreement between the two methods. Therefore, the proposed automatic method is a powerful way to provide rapid and accurate measurements for in vitro blood experiments in microchannels. Copyright © 2012 John Wiley & Sons, Ltd.
Numerical simulation of particle dynamics in an orifice–electrode system. Application to counting and sizing by impedance measurement
Authors: Isèbe Damien , Nérin Philippe
Published: November 2012

This paper describes how to numerically tackle the problem of counting and sizing particles by impedance measurement in an orifice–electrode system. The model allows to simulate the particle dynamics submitted to strong hydrodynamic stresses through a microorifice and to compute the voltage pulses generated by the modification of the inner dielectric medium. This approach gives important information about particles size distribution and allows to quantify the role of trajectory and orientation of particles on the size measurement. Copyright © 2012 John Wiley & Sons, Ltd.
A tool for enhancing strategic health planning: a modeled use of the International Classification of Functioning, Disability and Health
Authors: Sinclair Lisa Bundara , Fox Michael H. , Betts Donald R.
Published: November 2012

This article describes use of the International Classification of Functioning, Disability and Health (ICF) as a tool for strategic planning. The ICF is the international classification system for factors that influence health, including Body Structures, Body Functions, Activities and Participation and Environmental Factors. An overview of strategic planning and the ICF are provided. Selected ICF concepts and nomenclature are used to demonstrate its utility in helping develop a classic planning framework, objectives, measures and actions. Some issues and resolutions for applying the ICF are described. Applying the ICF for strategic health planning is an innovative approach that fosters the inclusion of social ecological health determinants and broad populations. If employed from the onset of planning, the ICF can help public health organizations systematically conceptualize, organize and communicate a strategic health plan. This article is a US Government work and is in the public domain in the USA.
Influence of landscape evolution on the distribution of floristic patterns in northern Amazonia revealed by δ13C data
Authors: Zani H. , Rossetti D. F. , Cohen M. L. C. , Pessenda L. C. R. , Cremon E. H.
Published: November 2012

The Amazonian lowlands include large patches of open vegetation which contrast sharply with the rainforest, and the origin of these patches has been debated. This study focuses on a large area of open vegetation in northern Brazil, where δ13C and, in some instances, C/N analyses of the organic matter preserved in late Quaternary sediments were used to achieve floristic reconstructions over time. The main goal was to determine when the modern open vegetation started to develop in this area. The variability in δ13C data derived from nine cores ranges from −32.2 to −19.6‰, but with nearly 60% of data above −26.5‰. The most enriched values were detected only in ecotone and open vegetated areas. The development of open vegetation communities was asynchronous, varying between estimated ages of 6400 and 3000 cal a BP. This suggests that the origin of the studied patches of open vegetation might be linked to sedimentary dynamics of a late Quaternary megafan system. As sedimentation ended, this vegetation type became established over the megafan surface. In addition, the data presented here show that the presence of C4 plants must be used carefully as a proxy to interpret dry paleoclimatic episodes in Amazonian areas. Copyright © 2012 John Wiley & Sons, Ltd.
How does a Brand Ally Affect Consumer Evaluations of a Focal Brand?
Authors: Voss Kevin E. , Gammoh Bashar S. , Fang Xiang
Published: November 2012

Published research has shown that an alliance with a well‐known, reputable brand can improve quality perceptions of a previously unknown focal brand. Much of this research is based on signaling theory's bonding hypothesis. However, customers face information search costs when evaluating brands with which they may be unfamiliar. The authors contend that, since consumers are self‐interested, they will prefer to realize cost savings for themselves relative to a future conditional opportunity to punish a false signal sender. Three studies show that the effect of brand ally information on quality perceptions of an unfamiliar brand is mediated by perceived risk reduction due to lower information search costs.
What is the Value of Luxury? A Cross‐Cultural Consumer Perspective
Authors: Hennigs Nadine , Wiedmann Klaus‐Peter , Klarmann Christiane , Strehlau Suzane , Godey Bruno , Pederzoli Daniele , Neulinger Agnes , Dave Kartik , Aiello Gaetano , Donvito Raffaele , Taro Koyama , Táborecká‐Petrovičová Janka , Santos Carmen Rodríguez , Jung Jaehee , Oh Hyunjoo
Published: November 2012

International luxury businesses are challenged by the identification and satisfaction of the common needs and desires of global market segments. Although luxury goods have become available to a wider range of consumers, the traditional conspicuous consumption model has been transformed into a new experiential luxury sensibility that is marked by a change in the way that consumers define luxury. Based on an empirical study in collaboration with American, European, and Asian researchers, the results provide evidence that consumers in various parts of the world purchase or wish to purchase luxury products for varied reasons but that such consumers generally possess similar values. Regardless of their countries of origin, the basic motivational drivers of luxury consumers are similar among the financial, functional, personal, and social dimensions of luxury value perceptions, although the relative importance of these dimensions varies.
Anti‐proliferative effects of physiological concentrations of enterolactone in models of prostate tumourigenesis
Authors: McCann Mark J. , Rowland Ian R. , Roy Nicole C.
Published: November 2012

Scope

There is evidence that a mammalian lignan, enterolactone (ENL), decreases the proliferation rate of prostate cancer cells, although previous studies have used concentrations difficult to achieve through dietary modification. We have therefore investigated the anti‐proliferative effects of ENL in an in vitro model of prostate tumourigenesis at concentrations reported to occur in a range of male populations.

Methods and results

The effects of 0.1 and 1 μM ENL on three markers of viability and proliferation (metabolic activity, growth kinetics, and cell cycle progression) were assessed in the RWPE‐1, WPE1‐NA22, WPE1‐NB14, WPE1‐NB11, WPE1‐NB26, LNCaP, and PC‐3 cell lines over 72 h. Based on these data, we quantified the expression levels of 12 genes involved in the control of DNA replication initiation using TaqMan real‐time PCR in the WPE1‐NA22, WPE1‐NB14, WPE1‐NB11, and WPE1‐NB26 cell lines. ENL significantly inhibited the abnormal proliferation of the WPE1‐NB14 and WPE1‐NB11 cell lines and appears to be a consequence of decreased expression of abnormal chromatin licensing and DNA replication factor 1.

Conclusion

In contrast to previous studies, concentrations of ENL that are reported after dietary intervention restrict the proliferation of early‐stage tumourigenic prostate cell lines by inhibiting the abnormal formation of complexes that initiate DNA replication.
Modeling of tensile strength of rocks materials based on support vector machines approaches
Authors: Ceryan Nurcihan , Okkan Umut , Samui Pijush , Ceryan Sener
Published: November 2012

In the predicting of geological variables, artificial neural networks (ANNs) have some drawbacks including possibility of getting trapped in local minima, over training, subjectivity in the determining of model parameters and the components of its complex structure. Recently, support vector machines (SVM) has been found to be popular in prediction studies due to its some advantages over ANNs. Because the least squares SVM (LS‐SVM) provides a computational advantage over SVM by converting quadratic optimization problem into a system of linear equations, LS‐SVM method is also tried in study. The main purpose of this study is to examine the capability of these two SVM algorithms for the prediction of tensile strength of rock materials and to compare its performance with ANN and linear regression (MLR) models. Total porosity, sonic velocity, slake durability index and aggregate impact value were used as input in modeling applications. Favorite performance evaluation measures were employed to assess developed models. The results determined in study indicate that the SVM, LS‐SVM and ANN methods are successful tools for prediction of tensile strength variable and can give good prediction performances than MLR model. Although these three methods are powerful artificial intelligence techniques, LS‐SVM makes the running time considerably faster with the higher accuracy. In terms of accuracy, the LS‐SVM model resulted in error reductions relative to that of the other models. Copyright © 2012 John Wiley & Sons, Ltd.
Reference ranges of atrioventricular valve areas by means of four‐dimensional ultrasonography using spatiotemporal image correlation in the rendering mode
Authors: Rolo Liliam Cristine , Nardozza Luciano Marcondes Machado , Araujo Edward , Hatanaka Alan Roberto , Rocha Luciane Alves , Simioni Christiane , Moron Antonio Fernandes
Published: November 2012

Objective

This study aims to determine reference curves for fetal atrioventricular valve areas by means of three‐dimensional ultrasound using the spatiotemporal image correlation (STIC) software.

Methods

This was a cross‐sectional prospective study on 328 normal fetuses between the 18th and the 33rd weeks of pregnancy. In order to obtain valve areas, the four heart chambers plane was used with the fetus in a dorsal posterior position. To construct reference ranges, a linear regression model was used, adjusted according to the coefficient of determination (R2). To calculate the reproducibility of the tricuspid valve area, the intraclass coefficient correlation (ICC) was used.

Results

The mean areas of the tricuspid and mitral valves ranged from 0.19 ± 0.08 and 0.20 ± 0.10 cm2 in the 18th week to 0.93 ± 0.31 and 1.06 ± 0.39 cm2 in the 33rd week, respectively. The intra‐observer and interobserver reproducibility was excellent with ICC = 0.997 and 0.933, respectively.

Conclusions

Reference curves for fetal atrioventricular valve areas were determined and presented good reproducibility. © 2012 John Wiley & Sons, Ltd.
Raman spectroscopy of core/shell silicon nanowires grown on different substrates
Authors: Khorasaninejad M. , Adachi M. M. , Walia J. , Karim K. S. , Saini S. S.
Published: November 2012

Crystalline–amorphous core–shell silicon nanowires (SiNWs) grown separately on glass and stainless steel substrates were investigated by Raman spectroscopy. Raman spectra confirmed the presence of crystalline and amorphous silicon phases in both samples. With respect to bulk silicon, the crystalline Raman peaks for the nanowires grown on a glass substrate showed much larger red shift and spectral broadening as compared to that of the nanowires grown on stainless steel. The Raman shift was attributed to local heating which was further confirmed by the reduction in red shift of the Raman spectrum at lower incident powers for both samples. For a low input power of 0.8 mW, the nanowires grown on stainless steel showed no shift in the first order Raman peak as compared to bulk silicon, however a small spectral broadening was still observed.

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TEM images for the nanowires grown on steel substrate.
Investigation of optical, structural, and chemical properties of indium sulfide thin films evaporated at low temperature by modulated flux deposition
Authors: Sanz C. , Guillén C. , Gutiérrez M. T. , Herrero J.
Published: November 2012

Indium sulfide thin films were successfully deposited on soda lime glass substrates by modulated flux deposition (MFD) at significantly lower substrate temperatures than in previous experiments. The influence of both experimental parameters sulfur source temperature (TS) and substrate temperature (T) on the optical, structural, and chemical properties were studied. Amorphous indium sulfide layers were obtained at T = 100 °C and crystallized as β‐In2S3 for T ≥ 150 °C. Quite high values were required for the TS parameter in order to ensure the formation of transparent β‐In2S3 thin films. No other polycrystalline phases were detected. Direct optical bandgaps of 2.58 eV (amorphous In2S3) and 2.73 eV (β‐In2S3) were estimated for film thicknesses of around 100 nm.
Phase transitions in C60·C8H8 under hydrostatic pressure
Authors: Francis E. A. , Durkó G. , Jalsovszky I. , Klupp G. , Kamarás K. , Kováts É. , Pekker S. , Kuntscher C. A.
Published: November 2012

High‐pressure infrared transmission measurements up to 9.5 GPa were carried out on the rotor–stator molecular cocrystal C60·C8H8. Helium served as pressure transmitting medium, which intercalates into the C60·C8H8 lattice. Thus, we investigated the pressure effects and effect of intercalation of helium into the C60·C8H8 lattice. The pressure‐induced shift of the vibrational modes of C60·C8H8 shows an anomaly around 3 GPa. This anomaly can be interpreted in terms of the orientational ordering transition of fullerene molecules accompanied by a change in the crystal symmetry, which causes the splitting of the vibrational modes. We compare the value of the critical pressure to that obtained earlier [Thirunavukkuarasu et al., J. Phys. Chem. C 112, 17525 (2008); Phys. Status Solidi B 244, 3857 (2007)].
Growth, dispersion, and electronic devices of nitrogen‐doped single‐wall carbon nanotubes
Authors: Oikonomou Antonios , Susi Toma , Kauppinen Esko I. , Vijayaraghavan Aravind
Published: November 2012

This paper describes the complete processes from growth to electronic devices of nitrogen‐doped single‐wall carbon nanotubes (N‐SWCNTs). The N‐SWCNTs were synthesized using a floating catalyst chemical vapor deposition method. The dry‐deposited N‐SWCNT films were dispersed in N‐methylpyrolidone followed by sonication and centrifugation steps to yield a stable dispersion of N‐SWCNTs in solution. The length and diameter distribution as well as concentration of N‐SWCNTs in solution were measured by atomic force microscopy and optical absorption spectroscopy, respectively. The N‐SWCNTs were then assembled into electronic devices using bottom–up dielectrophoresis and characterized as field‐effect transistors. Finally, the potential for application of N‐SWCNTs in sensors is discussed.

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The three stages of N‐doped SWCNT processing: (a) growth and collection on filter, (b) dispersion in NMP, and (c) dielectrophoretic assembly into transistor device.