bluuebunny/crossref_metadata_2025 huggingface dataset:
Ghost and the other
Authors: Broz Ludek
Published: June 2018

This article focuses on ghost-related othering: of those alive and those dead in a Siberian village; of those who subscribe to the existence of ghosts by certain Russian officials; of texts that do not reduce ghosts to a second order of reality from the genre of ethnography, and their authors from the rank of fellow anthropologists. Pushing the logic of the “ontological turn” in anthropology to its limits, it asks whether such instances simply resemble each other, or whether it is possible to discern some sort of ontological continuity between them. Could the similitudes be the effect of ghosts’ (perhaps fragmented and partial) existence, rather than their (monolithic, ultimate and unquestionable) non-existence?
Concrete’s memory
Authors: Carr Gilly
Published: June 2018

This paper explores the constraints upon archaeologists who working in the field of heritage studies who encounter tales of haunting, or have their own experiences with ghosts, during fieldwork. The discipline lacks the terminology to describe, analyse or understand such experiences, leading to either omissions, embarrassed anecdotes at the end of ‘serious’ discussions of fieldwork, or talking in metaphors. Using the case study of the Channel Islands, this paper explores ways in which archaeologists can talk and write about ghosts through recent understandings of the concept of ‘heritage’, through a rejection of UNESCO’s definitions of Intangible Cultural Heritage, and the adoption of the concept of ‘tangible intangibility’.
An Exploratory Study of Fresh Food E-Commerce in the UK and China
Authors: Shi Yangyan , Xie Chunxiao , Han Rui
Published: June 2018

Fresh food e-commerce has become a burgeoning branch in online markets and changed the circulation of fresh food. Concerning the background of e-commerce, this study tries to relate suppliers' awareness of promoting fresh food business with the logistic obstacles and consumer impacts. The article first introduces five guiding questions after reviewing present literature. To better understand the fresh food markets, it analyzes the operational model of respective suppliers in the UK and China separately. The article also describes primary data collection through the distribution of questionnaires to the sample population. According to the valid feedbacks, the article concludes different consuming trends in fresh food markets and finds that logistical services are still the biggest challenge which need to be improved. Based on the results, it provides recommendations to suppliers for improving the fresh food e-commerce.
Effectively Using Systems Thinking in New Product Development (NPD)
Authors: Galli Brian J.
Published: June 2018

This is a case study concerning technology start-up companies involved in systems thinking during new product development. It is found that systems thinking is pivotal to assisting project managers in moving a project from start to successful completion. The essence of systems thinking is getting all teams in a company to work together as one, to push forward new product development. The study reveals some of the challenges associated with implementing the systems theory in new product development for these companies. This area of study holds promise for continued future research. However, there are still some implementation issues in the real world that have been identified and perhaps are in need of further exploration.
Book-Tax Income Conformity and Earnings Quality
Authors: Abdallah Sara Ahmed
Published: June 2018

This article aims to investigate the incremental value of book-tax differences (BTD) for the future earnings post the Egyptian revolution crisis and also examine the changes in BTD information under earnings discretionary overestimation versus underestimation by Egyptian stock exchange (EGX) listed firms. The findings show a negative incremental BTD value for the one-year ahead earnings performance. This finding is more pronounced for large BTD regardless of its sign (positive/ negative). However, large BTD negative implications are more evident in firms managing earning upward. The findings advocate that BTD are more likely to be driven by earnings manipulation incentives than tax management incentives. The findings suggest a regulatory disclosure policy of a reconciliation of book and taxable incomes to help improve investors' understanding of the BTD potential sources.
Analyst Coverage and Corporate Governance of French IPOs
Authors: Millet-Reyes Benedicte
Published: June 2018

Analyst coverage has been associated with good corporate governance characteristics, especially in countries with weak investor protection. This hypothesis is tested for a sample of French IPOs covering the period 2004-2015. In theory, analysts can provide useful forecasts and recommendations for newly listed companies with a potential for asymmetric information. However, weak corporate governance practices may lead to their reluctance to provide coverage. Logistic regression results clearly indicate that financial analysts are more likely to follow IPOs with large institutional owners. However, this positive association disappears when French institutional shareholdings are combined with two-tier board structures and high debt levels, suggesting that analysts acknowledge the increased potential for inside monitoring and private information channels in these firms. In contrast, the impact of debt becomes positive when combined with foreign institutional ownership, indicating that analysts welcome foreign investors as promoters of good corporate governance practices.
New Generation Cooperatives as a Response to the Economic Crisis in Greece
Authors: Galatoulas Ioannis , Sergaki Panagiota , Apostolopoulos Konstantinos D. , Papagrigoriou Aristidis
Published: June 2018

The severe Greek economic crisis has created several financial and social challenges. The rise in unemployment had a consequence that a significant percentage of city-dwellers had to leave their homes mostly in Athens and continue their life in rural areas of Greece. Small agricultural holdings that were inherited and never utilized in the years of economic prosperity are now utilized. New business structures have emerged to tackle unemployment and the loss of income. As a result, the first new generation cooperative (NGC) named Efkarpon was established in Karditsa, Greece, in 2012. It is a vertically integrated cooperative, which uses innovation in production and processing of superfood fruits. Factor analysis and SWOT analysis are used to specify the cooperative potentials and manage members' expectations. The results reveal that the members joined in the Efkarpon mostly because they liked the innovative attributes of the effort and recognized entrepreneurial opportunities in superfoods. The credibility of the pioneers of this innovative venture seem to have played the key role.
A Mathematical Database to Process Time Series
Authors: Ponchateau Cyrille , Bellatreche Ladjel , Ordonez Carlos , Baron Mickael
Published: June 2018

In scientific research, the results of an experiment commonly take the form of a time series, in which such time series consists of measurements collected from a sensor over time. After time series are stored, mathematical models are derived using numerical methods. Even though there exist plenty of tools to store and analyze time series data, there is scarce research aimed at storing and querying derived models, which are the most important mechanism for a scientist to understand data. In this article, the authors propose to help scientists with a flexible database structure to persist and manage mathematical models with a mathematical models store, with extended features, to handle time series. In this article, the authors introduce the concept of a mathematical models store enriched with numerical processing methods to allow queries based on raw time series data. Then they introduce a prototype, that is an implementation of such a data store with PostgreSQL.
Predicting Stock Market Price Using Neural Network Model
Authors: Tripathy Naliniprava
Published: June 2018

The present article predicts the movement of daily Indian stock market (S&P CNX Nifty) price by using Feedforward Neural Network Model over a period of eight years from January 1st 2008 to April 8th 2016. The prediction accuracy of the model is accessed by normalized mean square error (NMSE) and sign correctness percentage (SCP) measure. The study indicates that the predicted output is very close to actual data since the normalized error of one-day lag is 0.02. The analysis further shows that 60 percent accuracy found in the prediction of the direction of daily movement of Indian stock market price after the financial crises period 2008. The study indicates that the predictive power of the feedforward neural network models reasonably influenced by one-day lag stock market price. Hence, the validity of an efficient market hypothesis does not hold in practice in the Indian stock market. This article is quite useful to the investors, professional traders and regulators for understanding the effectiveness of Indian stock market to take appropriate investment decision in the stock market.
Factors Influencing the Development of Information Systems Disaster Recovery Plan in the Ghanaian Banking Industry
Authors: Pobee Frederick , Opoku Daniel
Published: June 2018

Information systems (IS) have become an integral part of many organizations as they depend on it to execute their critical business function. The purpose of this research was to explore the enablers and inhibitors of information systems disaster recovery planning in organizations in the Ghanaian banking sector. In order to achieve this purpose, the protection motivation theory and the theory of planned behavior was used as the theoretical lens for this study. Eight hypotheses were developed to test the research conceptualization. Data analysis was performed using SPSS version 20.0. Using a survey of 207 managers in the Ghanaian banking sector, this article shows the factors such as perceived vulnerability, perceived severity, response efficacy, self-efficacy, attitude, subjective norms and perceived behavioral control positively influences motivation and intention to develop an information systems disaster recovery plan in Ghanaian banking industries.
Perfil do controller e a evolução histórica da profissão no contexto brasileiro
Authors: Fiirst Clóvis , Pamplona Edgar , Lavarda Carlos Eduardo Facin , Zonatto Vinícius Costa da Silva
Published: June 2018

O estudo investiga o perfil do controller e sua evolução histórica no contexto brasileiro, com base em anúncios derivados do jornal "O Estado de São Paulo". A metodologia utilizada para desenvolvimento do estudo é descritiva, com abordagem quantitativa e qualitativa dos dados e análise documental. A população de itens que contém a palavra "controller" no acervo do jornal é de 1.619, sendo a amostra da pesquisa, que corresponde apenas a anúncios inéditos, de 422 observações. Os dados foram analisados através de construto adaptado do estudo de Duque (2011), sendo realizado um check list para extração das informações. Os achados demonstram que o primeiro anúncio que procura por controller é datado de 1945, sendo este uma exceção na época. Ademais, verifica-se na década de 1970 o aumento da procura de forma relevante por controllers, com um perfil voltado principalmente a atividades de perfil técnico. A década de 2000 marca a "explosão" da procura por profissionais de controladoria, bem como uma maior necessidade de profissionais majoritariamente para desempenhar atividades de gestão, o que também sinaliza para o aumento da importância destes profissionais nas organizações, fato tal consolidado nos dias atuais (década de 2010), que também aponta o controller como ligado a atividades da área gerencial. Por fim, nota-se que o controller, quanto ao perfil comportamental, deve ter essencialmente liderança, possuir formação em contabilidade, economia, administração ou engenharia, bem como pós-graduação, em alguns casos, conhecimentos da língua inglesa e experiência em torno de 5 anos para corresponder ao que o mercado necessita.
Percepção dos docentes de contabilidade perante as alterações do patrimônio líquido
Authors: Gonzales Alexandre , Santos Ariovaldo dos
Published: June 2018

A contabilidade brasileira vem passando por mudanças no sentido de convergir suas normas às internacionais. Parte das mudanças normativas relacionadas à contabilidade afetou o patrimônio líquido das empresas, por meio da criação de contas ou de reclassificação de valores do patrimônio líquido e de outros elementos das demonstrações contábeis. O presente trabalho objetivou esclarecer questões relacionadas ao entendimento dos docentes de contabilidade sobre tais mudanças. O estudo elaborado foi caracterizado como descritivo, sendo uma pesquisa ex post facto, documental e de campo, e se utilizou de questionário para coletar informações junto ao público alvo, formado por professores de contabilidade em 1.115 cursos de bacharelado em Ciências Contábeis. No questionário foram apresentadas afirmativas, que os respondentes indicaram o grau de concordância com cada uma delas. Em seis das afirmativas houve uma tendência bem definida no comportamento das respostas, e deixou de haver uma tendência predominante na resposta ao se abordar a percepção sobre o impacto das mudanças em empresas de setores distintos. Essa heterogeneidade nas respostas se acentuou ao analisar as respostas segmentadas por titulação dos professores respondentes.
Composite Materials Monitoring by Fiber Optic Sensors
Authors: Efimov Mikhail E. , Volkovskiy Sergey A. , Kulikov Andrei V. , Strigalev Vladimir E.
Published: June 2018

The paper presents methods for testing the composite materials using two types of fiber-optic sensors as well as a method for using radiation of the vertical-cavity emitting laser radiation (VCSEL) for checking the material deformation and its performances. The deformation checking sensor is a fiber Bragg grating (FBG) with a spectrum width of 50 pm, which is interrogated by the VCSEL. A new algorithm for modulating the laser diode current is proposed for the FBG interrogation providing a dynamic range of at least 3 nm. A new interrogation method of impulse Fabry-Perot interferometer was proposed. The interrogation method was applied for a fiber-optic acoustic emission sensor manufacturing. The sensor was experimentally investigated by the impact of a 6 mm diameter steel ball and compared to a reference piezoelectric acoustic emission transducer.
Combined Effects of Variable Viscosity and Thermal Conductivity on Dissipative Flow of Oil-Based Nanofluid over a Permeable Vertical Surface
Authors: Etwire Christian John , Seini Ibrahim Yakubu , Musah Rabiu , Makinde Oluwole Daniel
Published: June 2018

Abstract: The combined effect of variable viscosity and thermal conductivity on dissipative flow of oil-based nanofluid over a permeable vertical plate with suction has been studied. The governing partial differential equations have been transformed into a coupled third-order ordinary differential equations using similarity techniques. The resulting third-order ordinary differential equations were then reduced into a system of first-order ordinary differential equations and solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results revealed that both viscosity and thermal conductivities of CuO oil-based nanofluid enhances the intensity of the skin friction coefficient and the rate of heat transfer at the surface of the plate. Furthermore, the thermal boundary layer thickness is weakened by the viscosity of CuO oil-based nanofluid, the Prandtl number, the suction parameter, the permeability of the medium and the thermal Grashof number
Radiative and Viscous Ohmic Dissipation on MHD Tangent Hyperbolic Fluid over a Convectively Heated Sheet in a Suspension of Dust Particles
Authors: Mamatha S.U. , Raju Chakravarthula S.K. , Mahesha  , Makinde Oluwole Daniel
Published: June 2018

The present study deals with steady incompressible magneto hydrodynamic hyperbolic tangent fluid flow induced by a convectively heated stretching surface with the suspension of dust particles, Darcy-Forchheimer, thermal radiation, viscous dissipation and Ohmic heating. Similarity transformations were used to convert partial differential equations (PDEs) to a system of nonlinear ordinary differential equations (NODEs) which are solved numerically by Runge-Kutta Fehlberg method. The effect of pertinent parameters on velocity and temperature profiles of both fluid and dust phase within the boundary layer has been studied by considering various values of controlling parameters. Additionally, the skin friction coefficient and reduced heat transfer coefficient have been examined for various values of the governing parameters. It is found that Hartmann number and Forchheimer parameter reduce friction factor and heat transfer rates.
The Flow of Radiated Carreau Dusty Fluid over Exponentially Stretching Sheet with Partial Slip at the Wall
Authors: Santosh H.B. , Mahesha  , Raju Chakravarthula S.K. , Makinde Oluwole Daniel
Published: June 2018

In this study, we addressed the impact of magnetic field on fluid flow and heat transfer of an in compressible Carreau fluid over exponentially stretching sheet in addition with fluid and dust particle suspension. Thermal radiation and non-uniform heat source/sink were included to develop heat transport phenomena. Dusty fluids have various applications such as processing of material, nuclear heat treatment, cooling process, treatment of waste water etc. The relevant governing equations are converted into ordinary differential equation using similarity transformation the transformed ordinary differential equations are then solved numerically by shooting technique along with Runge-Kutta method The effect of certain parameters on the dimensionless velocity and temperature are presented graphically. The physical quantities of the flow such as the friction factor and Local Nusselt number were calculated. It was found from the study that the velocity slip parameter increases the temperature profiles.
Magneto-Structural and Antimicrobial Properties of Sodium Doped Lanthanum Manganite Magnetic Nanoparticles for Biomedical Applications: Influence of Silica Coating
Authors: Ehi-Eromosele Cyril O. , Olugbuyiro J.A.O. , Edobor-Osoh A. , Adebisi A.A. , Bamgboye O.A. , Ojeifo J.
Published: June 2018

Coating of magnetic nanoparticles (MNPs) is usually a requirement prior to their utilization in biomedical applications. However, coating can influence the magneto-structural properties of MNPs thereby imparting their applications. The present work highlights the combustion synthesis of Na-doped lanthanum manganites (LNMO) and the influence of silica coatings on the magneto-structural properties, colloidal stability and antimicrobial properties of LNMO MNPs with their biomedical applications in mind. The crystalline perovskite structure was the same both for the bare and silica coated LNMO samples while there was a slight increase in crystallite size after coating. The FTIR spectral analysis, reduction in agglomeration of the particles and the elemental composition of the coated nanoparticles confirmed the presence of silica. The magnetization values of 34 emu/g and 29 emu/g recorded for bare and coated LNMO samples, respectively show that LNMO MNPs retained its ferromagnetic behaviour after silica coating. The pH dependent zeta potentials of the coated sample is-22.20 mV at pH 7.4 (physiological pH) and-18 mV at pH 5.0 (cell endosomal pH). Generally, silica coating reduced the antibacterial activity of the sample except for Bacillus spp where the antibacterial activity was the same with the bare sample. These results showed that while silica coating had marginal effect on the crystalline structure, size and magnetization of LNMO MNPs, it reduced the antibacterial activity of LNMO MNPs and enhanced greatly the colloidal stability of LNMO nanoparticles. Keywords: Na-doped lanthanum manganites, Silica coating, magnetic nanoparticles, biomedical applications, antimicrobial properties, colloidal stability
Low Cycle Fatigue Study of AISI 316L Cardiovascular Stent for Two Different Designs
Authors: Benhaddou M. , Abbadi M. , Ghammouri Mohammed
Published: June 2018

The main originality of this work consists in investigating low cycle fatigue of AISI 316L cardiovascular stents under hypertensive loading. For this purpose, two geometries of stents are expanded to various diameters and subjected to hypertensive blood pressure. Based on a combination between the fatigue parameter of Jiang-Sehitoglu and the relationship of Coffin-Manson, a numerical model for the prediction of the number of cycles to crack failure is developed. The stent is found to exhibit a fatigue life reduction with the increase of the expansion diameter due to ratchetting strain. In addition, the location of the failure is independent on the design. However, the U-shape strut permits a better distribution of pressure over the stent strut resulting in a longer fatigue life as compared to the Ω-shape.
Recognition of Coronary Atherosclerotic Plaque Tissue on Intravascular Ultrasound Images by Using Misclassification Sensitive Training of Discriminative Restricted Boltzmann Machine
Authors: Nguyen Kuong Trong , Uchino Eiji , Suetake Noriaki
Published: June 2018

Coronary atherosclerotic plaque has been extensively studied in pathological research. Improving the evaluation of vulnerable rupture is important to prevent acute heart failure. Intravascular ultrasound (IVUS) method is one of techniques to acquire information about atherosclerotic plaque, which is backscattered ultrasound signal sensed by IVUS transducer. The vessel structure and tissue components are then characterized in relation to the acquired signals. In this study, eight human coronary vessel sections are involved, and we use discriminative restricted Boltzmann machine (RBM) to classify coronary tissues as a target classifier. The quantization domain of IVUS signals are used to extract binary features for adapting Gaussian model of RBM. In addition, we propose a misclassification sensitive training of disRBM to deal with the class imbalances. The results are compared to the conventional integrated backscattered IVUS method (IB-IVUS) and the cost sensitive neural network for the same tasks.
The Investigation of Prestressed Pressure Pipes, Reinforced with Fiberglass Plastic
Authors: Trykoz L.V. , Kamchatnaya S.M. , Pustovoitova O.M. , Atynian A.O.
Published: June 2018

The problem of a combined action of reinforced concrete pipe and fiberglass safety cage. The prestressed cage not only decreases deformability of a pipe under load but protects the material of a pipe from agressive external factors. The process of force transfer from concrete pipe and fiberglass has been analyzed and the equation of stress and deformation for pipes and fiberglass has been deduced. It is shown that stress in fiberglass does not remain constant varying wall thickness, reducing towards the concrete core. Hoop stresses in the concrete core increase towards the centre of a pipe. Unlike known solutions the performed calculations take into account the performance of both layers – concrete and fiberglass. The total stresses in a concrete pipe in the most dangerous section from internal pressure and the reduction by fiberglass winding have been determined. The results obtained in the given work provide with the possibility of modelling long-term properties of composite reinforced concrete constructions and optimization of winding angle of fiberglass casing depending on the diameter of a pipe, tension force and the quantity of reinforcing filler.
Economic Implication of Safety - Policy on Manufacturing Safety Programme Performance
Authors: Adebiyi Kazeem Adekunle , Ajayeoba Abiola Olufemi , Akintan Adeshinaayomi Lawal
Published: June 2018

The study presents a mathematical approach of safety policy in terms of safety target and budget implementation factor. System dynamics were used to develop a hybrid model of accident occurrence and preventions in terms of pre-safety programme accidents, budgeting factor, proportion of budget to be implemented, strategy effectiveness index, workforce, accident proneness factor, prevented accidents, accident reduction target, probability parameter and estimated cost of accident. Hence, a cost savings/loss model was derived in terms of the identified parameters. Proportion of budget to be implemented (P) and accident reduction target (T) are the input policy parameters. At proportion of planned budget below P = 0.6 showed that the budget would not be enough to reduce any accident nor save any cost. Thus, throughout the simulation period, a minimum monetary savings of N10.775 millions was achieved at P=1 and T=10% and highest monetary savings of N36.955millions was achieved at and T=25%.
Microstructural Evolution and Mechanical Properties during Homogenization and Ageing Treatment of Al-Mg-Si Alloy Wire Cold Drawn
Authors: Bayarassou Mokhtar , Zidani Mosbah , Farh Hichem
Published: June 2018

The objective of the present investigation is to study the changes in microstructures and mechanical properties during ageing and homogenization treatment of Al-Mg-Si alloy wire cold drawn at the different deformation in ENICAB (Biskra), destined for the transport of electric energy. And also to understand the phase formation during the cold drawing of Al-Mg-Si alloy wires, as well as the combined influence of the plastic deformation level and the influence of aging temperature. Wire section reduction shows a change in microstructure and texture. Characterization methods used in this work is: Optical Microscopy (OM), Scanning Electron Microscope (SEM) and X-ray diffraction.
Strength Enhancement of Silty Sand Soil Subgrade of Highway Pavement Using Lime and Fines from Demolished Concrete Wastes
Authors: Banzibaganye Gerard , Twagirimana Emmanuel , Kumaran G. Senthil
Published: June 2018

The highway pavement quality and lifetime depend on its different layers such as subgrade, sub-base and base courses. It is of great importance for subgrade soil layer to have the excellent properties as it is the one to lower or increase the project cost. This paper discusses the utilization of lime and fines from concrete waste to enhance the strength of silty sand soil. California Bearing Ratio (CBR) and shear strength were evaluated. The content such as 0%, 2%, 4%, 6%, 8% and 10% were used. The CBR and shear strength of soil increased with the increase of lime or concrete content. The optimum lime and concrete content which maximized CBR were 6% and 8% respectively. The shear strength improvement was also noticed. No optimum content from both stabilizers which gave maximum shear strength.
Parametric Optimization of Citric Acid Production from Apple Pomace and Corn Steep Liquor by a Wild Type Strain of Aspergillus niger: A Response Surface Methodology Approach
Authors: Sekoai Patrick T. , Ayeni Augustine O. , Daramola Michael O.
Published: June 2018

In this work, parametric optimization of citric acid production (yield) from six process variables: apple pomace (AP) concentration, volume of corn steep liquor (CSL), pH, temperature, methanol concentration, and methanol addition time is reported. Fifty-four experiments were performed according to the Box-Behnken design method. A polynomial regression model was developed from the experimental data and effects of the variables were explained using response surface methodology approach. A coefficient of determination (R2) of 0.92 indicated the significance of the model. The optimum conditions for citric acid yield obtained from the model were 33.81 g/L of AP, 42.5 g/L of CSL, 2.05% (v/v) of methanol concentration, methanol addition time of 33 h, pH 4.54, and temperature of 32.88 °C with a corresponding yield of 62.00 g/L. Conducting an experiment using the optimum conditions gave citric acid yield of 68.26 g/L, a 10% increase over the model results.
Low Temperature Synthesis of Elongated Triangular Bipyramidal ZnO Nanostructures for Photocatalytic Activity
Authors: Singh Gurjinder , Panday Sudhakar , Rawat Mohit , Kukkar Deepak , Kumar Sanjeev , Basu Soumen
Published: June 2018

The manuscript reports wet chemical assisted low temperature synthesis of CTAB stabilized elongated triangular bipyramidal shape nanostructures of ZnO for photocatalytic degradation of methyle blue (MB) and congo red (CR) dyes. Physiochemical characterization has been carried out by X-ray diffraction, scanning electron microscope, transmission electron microscope and UV-visible spectroscope. Pure wurtzite structure of ZnO with crystallite size ~56 nm has been confirmed from X-ray study. Well dispersed particles with elongated triangular bipyramidal morphology have been observed through SEM. Fine resolved particles with varied aspect ratios ~80 X 200 ± 10 nm have been depicted by TEM images. UV-visible absorption analysis confirms the energy band gap of 3.43 eV for synthesized ZnO particles. Molecular composition and functional groups of CTAB were confirmed by FTIR spectroscopy. The potential applicability of the particles for photocatalytic degradation of MB and CR as standard analytical dyes was studied. Time bound study under UV irradiated source depicted more than 95% degradation of both dyes in separate experiments.
Scrutiny of Surface Plasmon Resonance Bands of Colloidal Cu and Cu-Ag Nanoparticles in Different Reaction Media for Stability Evaluation
Authors: Thar Aung Chan , Win Thaung Hlaing , Lwin Nyein Wint , Oo Than Zaw
Published: June 2018

The copper nanoparticles (CuNPs) were developed in two different reaction media (distilled water (DW) and ethylene glycol (EG)) by chemical reduction method using two different stabilizers (polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP)). We carried out a careful examination of the time evolution of surface plasmon resonance (SPR) bands (specifically, peak positions and intensities) of colloidal CuNPs so as to evaluate their stability. In addition, the changing pattern of SPR peak positions and intensities during the stability time period was also investigated. Effects of stabilizer materials, stabilizer concentration, Ag capping and reaction medium on the stability of CuNPs colloids have been highlighted. The maximum stability of CuNPs is 4 hours with stabilizer PEG and is 4 days with PVP in DW. They, with PVP, extend up to 10 days in the different reaction medium (EG). The stability time of CuNPs in EG is further lengthened to 20 days in the presence of Ag capping (Cucore AgshellNPs). Thus a proper selection of the stabilizing/capping agent and the reaction medium is critical in determining the stability of CuNPs colloids. The benefits of stabilization of CuNPs for real world applications are immense and this study would help in examinning the stability of other novel plasmonic metal nanostructures.
Study of Processability of Cu/Ni Bilayers Using Molecular Dynamics Simulations
Authors: Zhang Yan , Xiao Wan Shen , Peng Ping
Published: June 2018

Nanoscratching and nanoindentation simulations are performed to study the processability of Cu/Ni bilayers with interfaces using molecular dynamics (MD) method. Single crystals Cu and Ni are served as comparisons. In the nanoscratching processes, the interfaces of Cu/Ni bilayers appear as a barrier of dislocations gliding, and lead to larger friction forces and normal forces. For single crystals and bilayers, both their friction forces and normal forces increase with the increasement of scratch velocity at 100-300 m/s. Friction coefficients under scratching processes are calculated, and they are smaller than macrosacle scratching process because of coating effects of nano-chips on the tool. The effects are analyzed by conducting both molecular dynamics simulations in nanoscale and finite element simulations (FES) in macroscale. In the indentation process, the processing properties of Cu-Ni and Ni-Cu bilayers are different from each other, and their indentation forces are both larger than their single crystals. Recovery deformation takes place during the relaxation stage. When the tool is unloading, some workpiece atoms adhere to the tool. The simulation results of the two nanoscale machining processes reveal the strengthening mechanism of interface, and show comprehensive processability of metal bilayers.
Sulfonic Acid Functionalized Magnetite Nanoporous-KIT-6 for Removal of Methyl Green from Aqueous Solutions
Authors: Seyed Danesh Seyedeh Mahsa , Faghihian Hossein , Shariati Shahab
Published: June 2018

The sulfonic acid-functionalized KIT-6 magnetite mesoporous silica nanoparticles (Fe3O4@SiO2@KIT-6-SO3H NPs) were prepared as an adsorbent and used for the removal of methyl green from aqueous solutions. Characterization of the obtained adsorbent was done by FT-IR, SEM and EDX instruments. According to the experimental results, about 96.4 % of dye was removed from aqueous solutions at the adsorbent amount of 3.2 g L-1at pH = 3 and ionic strength = 0 during 10 min. The kinetic results indicated that the pseudo-second-order kinetic model was the best model for describing the adsorption kinetic ( = 0.9999). The isotherm analysis demonstrated that the equilibrium data were well fitted to the Freundlich isotherm model, showing a multilayer adsorption of the dye on the adsorbent surface. The maximum adsorption capacity for methyl green was obtained 196 mg g-1. Furthermore, the Fe3O4@SiO2-KIT-6-SO3H NPs could be simply recovered by external magnet and it exhibited recyclability and reusability for six cycles. The results showed that the Fe3O4@SiO2-KIT-6-SO3H NPs are appropriate adsorbent for removal of methyl green from real wastewater samples.
Reinforcing Mechanical Strength of Electrospun Chitosan Nanofibrous Scaffold Using Cellulose Nanofibers
Authors: Bohlouli Neda , Mirzaei Esmaeil , Ghanbari Hossein , Rezayat Sorkhabadi Seyed Mahdi , Faridi-Majid Reza
Published: June 2018

In this study, cellulose nanofibers (CNF) was used as a reinforcing material to improve mechanichal strenght of chitosan nanofibrous scaffold. Chitosan scaffolds with different amount of CNF ranging 5.0-20.0 Wt.% were fabricated by adding CNF to chitosan solutions before electrospinning. Both the tensile strength and tensile modulus of the scaffolds were increased as a result of CNF addition. An increase of 4.3 fold (from 2.9±0/02 to 12.7±0/4 MPa) in tensile strength and 4.04 fold (from 86.5±1.7 to 349.5±19.4 P) in Young's modulus were observed after addition of 15 wt. % CNF. The microscopy studies showed that the diameter of the electrospun fibers decreased with the addition of CNF. The diameter decreased from 175± 7 nm to 100±29 nm when 15 wt% CNF were added. Evaluation of cell adhesion by SEM showed that fibroblast cells not only can attachment on the surface of NFC reinforced scaffolds but also can infilterate inside the scaffolds. In addition, the nanocomposite schaffols dose not show any cytotoxic effect using MTT assay.
Structural and Mechanical Properties of Nanostructured Fe-Mn-C Alloys Prepared by Mechanical Alloying
Authors: Belaid Lounes , Bendoumia Meriem , Dakiche Mohamed , Mechri Hanane , Dahmoun Djaffar , Azzaz Mohamed
Published: June 2018

The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.
Synthesis and Characterization of Cobalt Nanoparticles Prepared by Arc Discharge Method Using an Ultrasonic Nebulizer
Authors: El-Khatib Ahmed M. , Badawi Mohamed S. , Roston Gamal D. , Khalil Alaa M. , Moussa Ramy M. , Mohamed Moustafa M.
Published: June 2018

Magnetic cobalt nanostructured was synthesized by a two-stage method. First, a solution of cobalt precursor droplets was prepared by an ultrasonic nebulizer. Second, the arc discharge method between two electrodes in an inert gas at atmospheric pressure is used to obtain the nanostructured cobalt powder. The sample obtained was characterized by X-ray diffraction (XRD). Scanning electron microscope (SEM), High Resolution Transmission Electron Microscope (HR-TEM), UV-Vis Spectrophotometry, zeta potential (ZP) and vibrating sample magnetometer (VSM). The dielectric constant, and AC conductivity of the prepared sample was determined in the frequency range of 4 Hz to 8 MHz. The investigations showed that the Co nanoparticles prepared in this way have smaller and homogeneous nanoparticles with spherical shape morphology with good stability and unique magnetic properties as compared with the bulky one. The dielectric properties analysis shows an enhancement in the dielectric constant and the AC conductivity of the Co nanoparticles.
Rattle-Type Diamine-Functionalized Mesoporous Silica Sphere for Carbon Dioxide Adsorption
Authors: Yuan Ning , Liu Zhi Wei , Wang Li Yan , Han Bao Hang
Published: June 2018

A rattle-type diamine-functionalized mesoporous silica sphere (DA-RMSS) was fabricated stepwise using a self-templating method through cationic surfactant assisted selective etching strategy. The rattle-type morphology of the obtained DA-RMSS material was disclosed by transmission electron microscopy, while its chemical composition was characterized by CHN elemental analysis, Fourier transform infrared spectroscopy, and solid-state 29Si cross-polarization/magic-angle-spinning nuclear magnetic resonance spectroscopic measurement, which corroborates the successful formation of siloxane network and the incorporation of organic component. Moreover, nitrogen adsorption–desorption isotherm measurement was conducted to reveal that DA-RMSS possesses large Brunauer–Emmett–Teller (BET) specific surface area of 814 m2g–1, pore volume of 0.78 cm3g–1, and narrow pore size distribution centered at 3.0 nm. Furthermore, its uptake property on carbon dioxide was also investigated in this contribution.
Synthesis of Nono-Crystalline Aluminum Carbide Using Thermal Treatment of Mechanically Activated Al and Graphite Mixture
Authors: Mohsen Saboktakin Rizi , Hamidreza Javadinejad , Sayed Ahmad Hosseini , Aghababaie Ebrahim
Published: June 2018

In this work, Nono-crystalline aluminum carbide particles were synthesized using both mechanical and thermal treatments. Frist, Al and graphite powders had been milled in a planetary ball mill. Then, milled mixtures have been annealed isothermally after the mechanical activation. The effects of two processes on the synthesized products were separately studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and simultaneous thermal analysis (STA) methods. Further, the grain size, lattice strain and dislocation density values were calculated according to XRD data. The results showed that mechanical alloying process can create an ultra-fine microstructure. The grain size was mostly reduced after 40 h milling as well as the heat treatment at 550 °c and 2 h. in fact, the high rate of plastic deformation of aluminum particle during milling process lead to rising the internal energy of particles, and finally, nanocrystals of Al4C3 formed with the size of 14 nm. However, thermal analysis indicated that the mechanical activation of aluminum and the presence of carbon can play key roles in synthesis of aluminum carbide. Key words: Mechanical alloying, annealing, Al and graphite powders, Solid state reaction, Nono-crystalline aluminum carbide.
Phosphorus Doped Carbon Nitride Nanotubes by Sequential Cation-Exchanging Reaction with Enhanced Photocatalytic Hydrogen Evolution
Authors: Che Hai Bing , Yan Xiao Xiao , Jia Zhi Yuan , Hu Peng , Wang Jinshu
Published: June 2018

In this work, a novel and facile sequential cation-exchanging strategy was developed to synthesize phosphorus doped g-C3N4 nanotubes, and resulted nanotubes were composed of small nanorods with length of several hundred nanometers by oriented aggregation. As obtained products exhibit greatly enhanced photocatalytic hydrogen evolution with rate of 4.59 mmol h-1 g-1, which is 16 times higher than that of the bulk g-C3N4 under visible light irradiation. Mechanism investigation reveals that the superior photocatalytic property could be attributed to its improved visible light absorbance, well suppressed charges recombination and nanostructural construction.
High Temperature Coatings for Oxidation and Erosion Protection of Heat-Resistant Carbonaceous Materials in High-Speed Flows
Authors: Yurishcheva Anna , Astapov Alexey , Lifanov Ivan , Rabinskiy Lev
Published: June 2018

Modern approaches to the creation of single-layer and multi-layer high-temperature coatings for the protection of heat-resistant carbon-containing composite materials from oxidation and erosion in the high-speed fluxes of oxygen-containing gases are analyzed. Particularly have been outlined the heat-resistant coatings, the main components of which are either super refractory transition metal borides (ZrB2, HfB2, TiB2) with the addition of carbides (SiC, ZrC, HfC, TiC, TaC), silicides (MoSi2, TiSi2, ZrSi2, TaSi2, WSi2) and nitrides (HfN, ZrN, TiN), or refractory oxides (HfO2, ZrO2), or more complex synthetic compositions based on oxide ceramics. The results of fire gas-dynamic tests of coatings of perspective compositions are presented. The potential architecture of ultra-high-temperature coatings with high efficiency of protective action is justified.
Improvement of Heat-Insulating Properties of Foam Concrete by Means of Mineral Additives
Authors: Barteneva Ekaterina A. , Ylesin Mikhail A. , Mashin Nikolay A. , Dubrov Dmitry V.
Published: June 2018

Foam concrete solidifying in natural conditions significantly shrinks, which causes deterioration of the porous structure and thus the increase in the heat conductivity of the material. One of the solutions for this problem is application of mineral modifiers. As the mineral modifiers the authors used the production waste – mineral additives (wollastonite, diopside) at natural dispersive capacity, as well as milled down to 300 and 600 m2/kg of specific surface. The application of perlite microspheres in foam concrete was investigated. The thermal conductivity coefficient was defined by rapid method. The optimal composition of the mixture for manufacturing foam concrete products with mineral additives ensures the decrease in the heat conductivity coefficient by 41-43% compared to the reference composition. At complete replacement of fly-ash aggregate by perlite microspheres the thermal conductivity coefficient decreases down to 0.062 W/ (m×°С). The economic effect of application of the developed foam concrete with the additive of wollastonite and diopside compared with the foam concrete presented on the market is equal to 259 / 388 RUB/m2 of an erected structure at the density of D300/ D400 respectively. Thus, directed regulation of the porous structure of cellular concrete leads to significant improvement of stability of the foam concrete mixture, which makes the prerequisites to the decrease in the thermal conductivity of the material and positive technical and economical results.
One of Geotechnological Technologies for Ensuring the Stability of the Boiler of the Pit
Authors: Sokolov Nikolai S.
Published: June 2018

.When building buildings and structures on unstable slopes, it becomes necessary to develop geotechnical technologies that ensure their stability. In addition, geotechnical techniques should be developed to ensure the safe operation of existing facilities built on them. Therefore, the main purpose of the work is to study one of the geotechnical technologies to ensure the stability of the fence fencing. As a rule, the opening of any foundation pit entails the emergence of additional efforts reducing the stability of the slopes. The task of ensuring the stability of the pit walls together with the loads on its bumps, as well as the general stability of the slope as a whole, is an urgent task of modern geotechnical construction. It is established that the structural solutions of the buried structures represent a special auxiliary containment structure, fence constructions, ground anchors that are arranged after the first stage of the excavation.
Current Issues of Developing Methodology and Software Solutions Used in Different Phases of Modelling Additive Production Processes
Authors: Ripetskiy Andrey , Vassilyev Stanislav , Zelenov Sergey , Kuznetsova Ekaterina
Published: June 2018

The mathematical methods and examples considered in the article allow efficient modeling of additive manufacturing processes by formulating a number of new criteria for geometry evaluation for compliance with the technological limitations of the additive manufacturing techniques. The aim of the research is the development of the new techniques, methods, algorithms and structured data aimed to validate the entire chain of additive manufacturing process.
Optimization for Epoxy/Paper Composites Insulated Tubular Bus Structure
Authors: Li Peng Hu , Ruan Ling , Li Cheng Lei , Yang Fan , Jin Hai Yun , Zhu Si Rui
Published: June 2018

Uniform standard in the structural design for insulated tubular bus is not available both at China and abroad, and there are few reports about insulated tubular bus, which causes a waste of resources and even leads to grid failure. In this paper, epoxy/paper composites insulated tubular bus was investigated and a two-dimensional model was preferred in the simulation due to the axial symmetry of insulated tubular bus. The distribution of electric field and temperature in composite insulated materials were studied with the changes of the diameter/thickness of copper pipe and the thickness of insulation materials. According to the results simulation results, the structure of insulated tubular bus was optimized, the thickness of copper pipe conductor and insulation had been greatly reduced. Compared to the non-optimized initial structure, the amount of copper pipe conductor used for the optimized insulated tubular bus was reduced by 48%, the amount of insulation materials were reduced by 52.5%, and the current density of copper pipe conductor increased by 92.2%.