bluuebunny/crossref_metadata_2025 huggingface dataset:
PREDICTING PRODUCTIVITY LOSS CAUSED BY CHANGE ORDERS USING THE EVOLUTIONARY FUZZY SUPPORT VECTOR MACHINE INFERENCE MODEL
Authors: Cheng Min-Yuan , Wibowo Dedy Kurniawan , Prayogo Doddy , Roy Andreas F. V.
Published: July 2015

Change orders in construction projects are very common and result in negative impacts on various project facets. The impact of change orders on labor productivity is particularly difficult to quantify. Traditional approaches are inadequate to calculate the complex input-output relationship necessary to measure the effect of change orders. This study develops the Evolutionary Fuzzy Support Vector Machines Inference Model (EFSIM) to more accurately predict change-order-related productivity losses. The EFSIM is an AI-based tool that combines fuzzy logic (FL), support vector machine (SVM), and fast messy genetic algorithm (fmGA). The SVM is utilized as a supervised learning technique to solve classification and regression problems; the FL is used to quantify vagueness and uncertainty; and the fmGA is applied to optimize model parameters. A case study is presented to demonstrate and validate EFSIM performance. Simulation results and our validation against previous studies demonstrate that the EFSIM predicts the impact of change orders significantly better than other AI-based tools including the artificial neural network (ANN), support vector machine (SVM), and evolutionary support vector machine inference model (ESIM).
BENDING BEHAVIOUR OF GLULAM BEAMS REINFORCED WITH CARBON FRP PLATES
Authors: Glišović Ivan , Stevanović Boško , Petrović Miloš
Published: July 2015

The idea of reinforcing glued laminated timber (glulam) beams came in response to the need to improve the mechanical properties, as well as to ensure higher reliability of this type of structural elements. This paper describes an experimental program which examines the reinforcement in flexure of glulam beams with carbon fibre reinforced plastic (CFRP) plates. Fifteen beams reinforced with CFRP at the tension side and five unreinforced control beams were instrumented and tested to failure in a four-point bending configuration. The mechanical properties of reinforced beams are compared to those of unreinforced beams with regard to the load-deflection behaviour, failure mode, ultimate load capacity, stiffness and strain distribution. The experimental results demonstrated the beneficial effect of the proposed reinforcing solution in terms of strength, stiffness and ductility.
RELIABILITY ANALYSIS OF THE LATERAL TORSIONAL BUCKLING RESISTANCE AND THE ULTIMATE LIMIT STATE OF STEEL BEAMS WITH RANDOM IMPERFECTIONS
Authors: Kala Zdeněk
Published: July 2015

The paper deals with the analysis of reliability of a hot-rolled steel IPE-beam designed according to Eurocodes. A beam at its ultimate limit state is considered. The load acting on the beam consists of permanent and long-term single variation actions. The beam is loaded with end bending moments about the major principal axis. The beam is susceptible to lateral torsional buckling between the end supports. Reliability of the beam is assessed using probabilistic analysis based on the Monte Carlo method. Failure probability is a function of the random variability of the loadcarrying capacity and the random variability of load effects. The variability of the load-carrying capacity is influenced by the variability of initial imperfections. Imperfections are considered according to experimental research. Numerical studies showed that the failure probability is significantly misaligned. High values of failure probability were obtained for slender beams, for beams loaded only by permanent load action, and for beams loaded only by long-term single variation load. In further studies the values of partial safety factors of load and resistance were calibrated so that the failure probability had a target value of 7.2E–5. Relatively high values of partial safety factors were obtained especially for beams with high slenderness.
A FUZZY ANALYTIC NETWORK PROCESS METHOD FOR RISK PRIORITIZATION IN FREEWAY PPP PROJECTS: AN IRANIAN CASE STUDY
Authors: Valipour Alireza , Yahaya Nordin , Md Noor Norhazilan , Kildienė Simona , Sarvari Hadi , Mardani Abbas
Published: July 2015

Risk assessment is one of the most important factors in achieving success in public-private partnership (PPP) projects. Some relationships between risks in freeway projects have been established. The occurrence of each risk can worsen the effects of others such as a negative impact of financial risks on construction risks. This paper is aimed at prioritizing significant risks in freeway PPP projects applying a fuzzy analytic network process (FANP) method for overcoming the problems of interdependencies and feedback among different risk-ranking alternatives. Data on the study have been collected through a literature review, an interview and a questionnaire survey distributed to experts in the field of freeway PPP projects. The obtained results have shown that financial, legal and political risks are the most significant groups, although improper design, changes in the value of granted lands and the termination of concession are the most important risks. The findings help with strengthening the capabilities of developing countries for risk management in freeway PPP projects.
TRANSPARENCY OF UNIVERSITY RANKINGS IN THE EFFECTIVE MANAGEMENT OF UNIVERSITY
Authors: JAROCKA Marta
Published: July 2015

University rankings are extremely important not only for future student, but also for universities themselves. They have a large impact on the institutions of higher education. A lot of universities believe, that rankings help them to maintain and create a reputation. Ranking systems function as some kind of fashion arena, where universities make comparisons between themselves. Universities want to improve their position in published classifications, so very often they try to change their policy and strategy. They also try to influence the ranking indicators, for example by hiring Nobel Prize winners. Therefore, there is an increasing need for reliable and transparent information about schools. However universities need not only statistical data, but also the tools, which will be useful in their comparisons and evaluations. The article presents the possibility of using one of the methods of graphic presentation of multidimensional empirical data structure, so called RGM, proposed by M. Rybaczuk. Thanks to this method universities could easily compare one another. They also could identify the fields of their activities, in which they are able to be better. The proposed way of graphical presentation of the universities could be a useful addition to traditional rankings, which just show us a lists of schools from the best to the worst.
DYNAMIC INTELLECTUAL CAPITAL MODEL IN A COMPANY
Authors: SHATREVICH Vladimir , ŠČEULOVS Deniss , GAILE-SARKANE Elina
Published: July 2015

The aim of this paper is to indicate the relations between company’s value added (VA) and intangible assets. Authors declare that Intellectual capital (IC) is one of the most relevant intangibles for a company, and the concept with measurement, and the relation with value creation is necessary for modern markets. Since relationship between IC elements and VA are complicated, this paper is aimed to create a usable dynamic model for building company’s value added through intellectual capital. The model is incorporating that outputs from IC elements are not homogeneously received and made some contributions to dynamic nature of IC relation and VA. Variables that will help companies to evaluate contribution of each element of IC are added to the model. This paper emphasizes the importance of a company’s IC and the positive interaction between them in generating profits for company.
Population aging in Slovenia: A spatial perspective
Authors: Kerbler Boštjan
Published: July 2015

The Slovenian population is aging. In order to best adapt to this demographic change, it is necessary to face this issue and to study it from the perspective of various disciplines, including geography. This article therefore especially focuses on the spatial characteristics of population aging in Slovenia in addition to general characteristics. The findings show that population aging in Slovenia is not uniform; instead, there are large differences in population aging in Slovenia. In addition to general social processes such as falling birthrates and increasing life expectancy, these are primarily the result of spatial movement of the population. The conclusion presents some consequences that will arise in Slovenian territory and society in the future due to population aging.
Coastline changes on the Slovenian coast between 1954 and 2010
Authors: Kolega Nataša
Published: July 2015

Due to a dense population and the presence of various activities, among which tourism and port activities must be highlighted, the Slovenian coast is subject to constant changes. This article analyzes the extent of these changes between 1954 and 2010, which coincides with a time of major coastline changes resulting from intense development of tourism and the commercial port. The analysis was based on a comparison of aerial photographs from 1954 and 2010. The changes were determined and measured on transects 50 meters apart. The land area gained and lost during this time was also calculated and the coastline was classified into four different types based on the level of naturalness and anthropogenic transformations.
A methodology for natural landscape typification of Slovenia
Authors: Perko Drago , Hrvatin Mauro , Ciglič Rok
Published: July 2015

Based on digital data on relief, rock, and vegetation, the most significant elements of the internal structure of Slovenian landscapes and at the same time of their external appearance, a geographic information system and verification in the field were used to create several natural landscape typologies of Slovenia with a varying number of types. The most generalized typology is based on the spatial overlap of four relief, seven lithological, and seven vegetation units. It has twenty-four landscape types: four flat, eleven low hilly, six hilly, and three mountainous types.
Sustainable spatial development in the Alps
Authors: Nared Janez , Razpotnik Visković Nika , Komac Blaž
Published: July 2015

This special issue of Acta geographica Slovenica discusses selected topics in spatial development in the Alps from the perspective of spatial planning legislation, stakeholder engagement in spatial planning decisions, tools that enable the effective flow of expertise and exchange of instruments, and best practices across the Alps, as well as from the economic perspective using the example of Alpine regions’ reaction to the economic crisis that affected Europe and the rest of the world at the end of the past decade. By including articles written as part of the WIKIAlps project, which was financed through the EU transnational cooperation program Alpine Space, this special issue seeks to invigorate discussions on sustainable spatial development in the Alps and thus contributes to a greater familiarity with this issue and to more prudent decisions.
Post-socialist urban growth of Bucharest, Romania – a change detection analysis on Landsat imagery (1984–2010)
Authors: Mihai Bogdan , Nistor Constantin , Simion Gabriel
Published: July 2015

In this study, Bucharest, the capital city of Romania was selected as a case study. Based on time series of Landsat TM imagery and statistical data, an analysis on urban growth from 1984 to 2010 was performed, using an integrated approach of remote sensing and GIS techniques. The land cover data were validated by CORINE Land Cover maps. The results revealed that rapid urban growth of the Bucharest region led to accelerated land use conversion from cropland to built-up land. The processes of deindustrialization in the core city and industrialization to the ring road represent other driving factors for spatiotemporal pattern of built-up land. The paper will discuss these processes and their impact on economic growth and residential suburbanization of the studied region.
Structural changes in land use of agricultural holdings in hilly rural areas
Authors: Knific Kristina , Bojnec Štefan
Published: July 2015

This paper analyses structural changes in agricultural holdings in the Škofja Loka region focusing on land use in the years 2000 and 2010. The analysis is conducted for the Škofja Loka region by socio-economic types of agricultural holdings, and by territories with different levels of economic development and different natural factors for agricultural production. Structural changes are different between municipalities with different natural factors for agricultural production and different levels of economic development as well as socio-economic types of agricultural holdings. State support for agricultural activity has mitigated overgrowth of agricultural land on naturally less favoured territories.
Towards more resilient economies in Alpine regions
Authors: Brozzi Riccardo , Lapuh Lucija , Nared Janez , Streifeneder Thomas
Published: July 2015

The economic crisis the world has faced since 2007 has had devastating effects on many regions to various degrees. How regions respond to economic shock depends on regional economic structure and performance, administrative capacity, resources, human capital, social capital, and other factors, and is perceived as resilience: the ability of a regional economy to withstand, absorb, or overcome an external economic stress. Because one of the future strategic goals for the Alpine Space Programme area is fostering its resilience, we studied the performance of Alpine regions in the pre- and post-crisis period in order to assess the effects of the economic crisis and to provide basic directions on how to make the Alps more resilient in the future. The results have revealed differences among three selected groups of regions as well as some country-specific characteristics of the regional response that can generally be seen in the weaker performance of some Italian and Slovenian regions.
Campaniforme no funerario en la provincia de Toledo: el yacimiento de Las Vegas. De nuevo el Valle de Huecas
Authors: Barroso Bermejo Rosa , Bueno Ramírez Primitiva , Vázquez Cuesta Antonio , Odriozola Lloret Carlos P. , Uribelarrea del Val David , López Jiménez Oscar , De Balbín Behrmann Rodrigo , Peña Chocarro Leonor , Yravedra Sainz de los Terreros José
Published: July 2015

Presentamos los resultados de los sondeos del yacimiento de Las Vegas, Huecas (Toledo). Se trata de un área abierta, junto al arroyo y al pie de la necrópolis de Valle de las Higueras. Un fuerte depósito de coluvión sepulta el yacimiento. Sin evidencias en superficie, su detección se realizó mediante prospección geofísica. Carece de estructuras y está formado por un único estrato, un depósito secundario que contiene campaniforme Ciempozuelos y metal, con una fecha C14 de la 2ª mitad del III milenio a.C. La cerámica es el material más abundante. Su estudio macroscópico y mediante fluorescencia de rayos X (FRX) avala su producción local, la rápida formación del depósito y su larga exposición en superficie. Planteamos que el depósito procede de la limpieza y mantenimiento de un área de ocupación anexa. El patrón de poblamiento parece seguir las tierras bajas del valle con ocupaciones cuyas producciones cerámicas difieren de las de los contextos funerarios.
Emotional Prediction and Content Profile Estimation in Evaluating Audiovisual Mediated Communication
Authors: Kotsakis Rigas , Dimoulas Charalampos , Kalliris George , Veglis Andreas
Published: July 2015

The present paper focuses on the extraction and evaluation of salient audiovisual features for the prediction of the encoding requirements in audiovisual content. Recent research showed that encoding decisions can be really crucial during audiovisual mediated communication, where poor encoding may lead to unaccepted Quality of Experience (QoE) or even to the creation of negative emotional response. In contrast, exaggerated high quality encoding may create increased bandwidth demands that are associated with annoying delays and irregular playback flow, resulting again in QoE degradation with similar emotional repulsion. Thus, there has to be a careful treatment with proper encoding balance during the production and deployment of mediated communication audiovisual resources. Such machine-assisted creativity is investigated in the current work, with the utilization of applicable audiovisual features, QoE metrics and emotional measures, aiming at implementing intelligent models for optimal audiovisual production and encoding configuration in demanding mediated communication applications and services.
The Effects of the Macroeconomic Policies Applied in Romania
Authors: Gabriela Dobrota
Published: July 2015

The realized research aimed to achieve the following objectives: the presentation of the domains envisaged by the measures taken by the authorities to ensure the economic viability; analysis of the main lines of action at the level of specified components, adopted by authorities from Romania; the identifying of the effects of macroeconomic policies on the economic environment by the stepwise presentation of its evolution; the cleavage of a set of relevant conclusions concerning the need to promote macroeconomic policies corresponding to economic development phase. The conclusion is that the authorities should implement measures to support the business sector, assimilation of techniques and new technologies so as to ensure the labor productivity growth and economic competitiveness at international level, the efficient use of resources, creating jobs and modernize social protection systems, rapid absorption of European funds and strengthen the financial system.
Computational Analysis of Hydrogen-Fueled Scramjet Combustor Using Cavities in Tandem Flame Holder
Authors: Roga Sukanta , Pandey Krishna Murari
Published: July 2015

This work presents the computational analysis of scramjet combustor using cavities in tandem flame holder by means of 3D. The fuel used by scramjet combustor with cavities in tandem flame holder is hydrogen, the fluid flow and the work is based on the species transport combustion with standard k-ε viscous model. The Mach number at inlet is 2.47 and stagnation temperature and static pressure for vitiated air are 1000K and 100kPa respectively. These computational analysis is mainly aimed to study the flow structure and combustion efficiency. The computational results are compared qualitatively and quantitatively with experimental results and these are agreed as well. Due to the combustion, the recirculation region behind the cavity injector becomes larger as compared to mixing case which acts as a flame holder. From the analysis, the maximum Mach number of 2.33 is observed in the recirculation areas.
Some Aspects of Reliability Measures of Polymer Composites Stressed by Climatic Environment
Authors: Valis David , Krzyzak Aneta
Published: July 2015

The paper deals with some selected methods for essential reliability measures estimation. Results for polymer composites are presented. The polymer composites were placed in various climatic environments and stressed with thermal and humidity load. These climate simulated accelerated influence of operational environment which the composites percept in service operation. After these stresses mechanical strength tests were performed. Outcomes of these mechanical tests were used for reliability characteristic estimations. For assessment of reliability measures several statistical tests were used. In this paper we present fundamental reliability measures of composites which were obtained during environment accelerated tests as basic research results.
Assessment of Off-Line Diagnostic Oil Data with Using Selected Mathematical Tools
Authors: Vališ David , Žák Libor
Published: July 2015

The paper deals with assessment of oil filed data from heavy off-road vehicle. The oil sample is collected off-line and processed consequently in a tribolaboratory. We call the outcomes from tribolaboratory as oil field data. Firstly we apply selected regression functions for description of the most interesting oil particles generation. It is the vehicle engine and its metal – ferrum, lead or cooper – oil data which are explored for further utilisation. We apply and present methods of multi-variate regression analysis to model the metal – Fe and Pb – data and provide outcomes + estimations for system operation so far and also proposals for system further operation. The novelty is to providing inputs for soft failure identification, to helping to change the life cycle costing, to change the system of maintenance policy, system operation and mission planning.
A Gyroscopic Damper System – A Damping Control with New Performance
Authors: Scheurich Bastian , Gentner Michael , Frey Michael , Gauterin Frank
Published: July 2015

A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibration energy. Different damper characteristics are achieved by different velocities of the inner ring. From almost zero torque output to high torque output, this damper has a huge spread. In this paper a control concept for a LQR is presented. The objective of the control is an adequate motion of the gyroscope to a desired damping characteristic of a passenger car.
Modeling and Dynamic Analysis of a Novel Hydro-Pneumatic Suspension System
Authors: Yang L. , Yang Fan , Xia M.B.
Published: July 2015

This study presents a modeling procedure and dynamic analysis for a novel hydro-pneumatic suspension system, in which the gas chamber has been integrated into the main structures. The modeling of the novel hydro-pneumatic suspension system has been established based on the mass conservation and force balance and the dimension has been obtained through a design optimization approach. The simulation results of the established model have been compared with those obtained through ADAMS, and good match can be observed.
Characteristic Feature of Dynamic Motion for Servo Press Machine by Direct Modeling Analysis
Authors: Yamazaki Takanori , Watanabe Akihiro
Published: July 2015

Servo press machine can enable us to high precision, but the dynamic behavior does not seem to be considered well. In order to improve the accuracy in manufacturing, it has been discussed effectiveness of reducing the elastic deformation of die structure on forming by mechanically compensating die structure which includes a servo die cushion system.
Solution of Non-Fourier Temperature Field in a Hollow Sphere under Harmonic Boundary Condition
Authors: Bahrami Amin , Hosseinzadeh Siamak , Ghasemiasl Ramin , Radmanesh Morteza
Published: July 2015

Analytical solution of the axisymmetric two-dimensional non-Fourier temperature field within a hollow sphere is investigated considering Cattaneo-Vernotte constitutive equation with general time-dependent heat flux. The material is assumed to be homogeneous and isotropic with temperature-independent thermal properties. The method of solution is the standard separation of variables method. Duhamel integral is used for applying the time-dependent boundary conditions. The presented solution is applied to special case of harmonic heat flux on outer surface.
Compression Molding Cure Cycle Modelling and Optimization for Large Polymeric Composite Parts Processing
Authors: Tarasov I.V. , Shevtsov S.N. , Zhilyaev I.V. , Orozaliev E.E.
Published: July 2015

In order to improve quality and productivity of polymeric composites production we suggest the technique of process simulation and optimization for large parts manufactured by compression molding. Optimal process design includes coupled heat transfer / thermo kinetic cure process formulation, its three-dimensional finite element model (FEM) implementation, its transient analysis at the parameterized thermal control law, and Pareto-based optimization, at which we determine control law parameters ensuring minimum standard deviations of the degree of cure within the cured body. We illustrate this approach via examples of two distinct cases of closed mould design concepts: one for moulds heated in autoclaves by the pressurized heated gas, which acts on the mould surface almost uniformly, and another for moulds with independently controlled built-in electrical heaters such as strip heaters or heated platens that are positioned along the length of the die at locations determined by structural features of the cured part. The suggested approach makes the process design more predictable, easier, faster, and more reliable. It can be adapted to specific manufacturing conditions and allows optimizing tools design and processing conditions before the mould and process control are made.
Quantitative Evaluation of Voids in Lead Free Solder Joints
Authors: Mallik Sabuj , Njoku Jude , Takyi Gabriel
Published: July 2015

Voiding in solder joints poses a serious reliability concern for electronic products. The aim of this research was to quantify the void formation in lead-free solder joints through X-ray inspections. Experiments were designed to investigate how void formation is affected by solder bump size and shape, differences in reflow time and temperature, and differences in solder paste formulation. Four different lead-free solder paste samples were used to produce solder bumps on a number of test boards, using surface mount reflow soldering process. Using an advanced X-ray inspection system void percentages were measured for three different size and shape solder bumps. Results indicate that the voiding in solder joint is strongly influenced by solder bump size and shape, with voids found to have increased when bump size decreased. A longer soaking period during reflow stage has negatively affectedsolder voids. Voiding was also accelerated with smaller solder particles in solder paste.
Adaptable High-Tech Mechatronic Equipment with Laser Scanning for Multicontrol 3D of Complex Components from Automotive Industry
Authors: Voicu Adrian Cătălin , Gheorghe Gheorghe Ion
Published: July 2015

Progressive replacement of traditional tools with intelligent technological equipment becoming more complex is one of the most important aspects of the development of production processes in all industrial fields. Intelligent measurement and integrated dimensional control are needed to ensure the quality of the product or industrial manufacturing process, whatever the field. Because the automotive industry is one of the most important industries in the world, manufacturing systems engineering, control methods and techniques, and assurance of quality, present particular interest by the economic results, in particular the reduction of working time and production costs. In a perfect world or in an integrated production environment, the new 3D measurement systems, by providing the quality control integrated into the production line would be able to measure all the necessary parameters in a single step, without errors and render the results in the same way to the manufacturing networks with computers, in formats useful for CNC machines control and process management.
Generating Guided Waves for Detection of Transverse Type-Defects in Rails
Authors: Teidj Sara , Khamlichi Abdelaltif , Driouach Abdellah
Published: July 2015

Detection of damage in rails can be achieved by using ultrasonic guided waves. It is practical that these waves can propagate as lengthy as possible along the rail structure. In this work, the generation of adequate guided waves is considered by performing pertinent laser irradiation of the rail head. Special laser spots were applied through out-of-phase masks collocated on both sides of the rail. Simulation of this excitation configuration was performed by means of the finite element method. It was found that the proposed method enables to trigger sufficiently high stress pulses and generate adequate pattern of waves from a lot of other modes that are likely to exist for a common rail. These waves were found to be sensitive to small localized transverse like defects in the rail system.
Imaging Subsurface Water Pipe Using GPR and Evanescent Waves: Experimental and Simulations Data
Authors: Iftimie N. , Dobrescu Gabriel Silviu , Savin A.
Published: July 2015

In this paper there are presented a series of methods and algorithms for signal processing (A-scan) and image processing (B-scan) which allow an easier and more accurate interpretation of the inspection results. The methods and the algorithms were tested for detection of a buried pipe, made of glass fiber polyester composite with a diameter of 1.3m, first when the survey conditions allowed only the scanning along the pipe, the most disadvantageous situation, but it has imposed by the configuration of the examined zone. After a few days of construction works, the site was prepared for inspection, orthogonally on the first scan direction.
Experimental Investigation on Dynamic Characteristics of Magneto-Rheological Fluid Suspension through on Road Comfort Testing
Authors: Saravanan K.G. , Mohanasundara Raju N.
Published: July 2015

The present study deals with the application of the Magneto-Rheological (MR) fluid assisted semi-active damper as a replacement to the conventional suspension system in Maruti 800 car (source vehicle). MR fluid damper is designed, fabricated and automated with a microcontroller. This experimentation is carried out with real time instrumentation on the selected road profile as a vehicle dynamic approach. Results obtained from the travel imply that MR fluid suspension suppresses the vibrations more effectively than the existing passive damper system. The MR fluid dampens the acceleration and displacement of the piston to a greater extent thereby controlling the ride comfort.
A Linear Quadratic Integral Design Approach for the Automatic Control System of a Launch Vehicle
Authors: Stoica Adrian Mihail , Constantinescu Cristian Emil , Nechita Silvia
Published: July 2015

This paper presents a design approach for the automatic flight control system of a launch vehicle using a linear quadratic integral technique together with a fixed gain Kalman filter. Its purpose is to analyse the stability and tracking robustness performances of the control system designed via this approach when atmospheric disturbances, modeling uncertainties and structural flexible modes of the launcher are taken into account.
The Limits of Downsizing - A Critical Analysis of the Limits of the Agile Flying Wing MiniUAV
Authors: Prisacariu Vasile , Boşcoianu Corina , Cîrciu Ionică , Boşcoianu Mircea
Published: July 2015

The missions of small flying wing UAVs require maneuver capabilities as well as optimal flight performance to balance the low operating and manufacturing costs. The basic principles in designing aviation structures must be readjusted due to the innovative concepts regarding the use of advanced materials as well as to the perspectives of using alternative energy aboard UAVs. The current paper is a synthesis of the 2D and 3D aerodynamic analysis of small swept flying wing UAVs that offers a global image of the possibilities of a multidimension optimization (miniaturization-scalability, payload-flexibility, minimum performances requirements).
Lubrication for Moving Mechanical Systems Used in Spacecraft
Authors: Krishnan Sathyan
Published: July 2015

Spacecraft, irrespective of their mission’s purpose, contain a number of moving mechanical assemblies such as control moment gyros, momentum/ reaction wheels, gyroscopes, scanners, solar array drives, etc. Most problems encountered with these moving systems are related to tribology and, specifically, lubrication. Lubrication problems result from the loss of lubricant from the working zone by evaporation, surface migration, etc. Therefore, to ensure long-term uninterrupted performance of these systems, an efficient lubricant replenishment system is essential. This article describes various lubricating methods and lubrication systems used for the successful operation of some of these systems for the entire mission periods.
An Improvement of the Rapidly-Exploring Random Tree Method for Path Planning of a Car-Like Robot in Virtual Environment
Authors: Gîrbacia Teodora , Mogan Gheorghe
Published: July 2015

In this paper we present a method of reducing the computational complexity necessary in path planning for a car-like robot in order to generate the optimal path according to the constrains set by the user. The proposed method implies adding the following constrains: setting the maximum and minimum distance between the possible paths and the obstacles placed in the virtual environment in order to reduce the simulation time and to obtain a real-time application and to remove the paths that contain unnecessary turns around the environment without avoiding an obstacle. By applying this method the simulation complexity is reduced and the optimal path is easier to find.
Optimal Location of Robot Base with Respect to the Application Positions by Using Proper Neural-Network Method
Authors: Ciupitu Liviu , Olaru Adrian
Published: July 2015

Usual the location of robot base with respect to positions (configurations) of an application that the robot must reach is choose in such a way that the application points to be into working space of robot by avoiding the obstacles. Or the application is build from the very first beginning in such a way that all application points to be in the working space of robot because usual the robot base is fixed to the ground. But this is not the optimal solution with respect to an objective function which represents for example minimum time of motion during a cycle, or minimum consumption of energy, or maximum precision, or combination of these. Some objective functions could results from the specificity of the application like is the case of casting of forging where the accumulation of heat for example could be one of the optimization criteria. For example in the automotive industry the owners prefer to replace the whole robotized line when the product is changed instead of reprogramming robots because the prices of robots is decreasing and the price of reprogramming is increasing. For such a situation the placing of robot base in an optimum location from the very first beginning so that the time or/and energy consumption to be minimum is an essential initial task, especially for large series productions. The proposed paper is dealing with the subject of moving the base of robot with respect to the application points so that an objective function representing the minimum time of motion during a cycle to be fulfilled.
Hybrid Solar-Wind Stand-Alone Energy System: A Case Study
Authors: Corsiuc Georgiana , Mârza Carmen , Ceuca Emilian , Felseghi Raluca Andreea , Şoimoşan Teodora
Published: July 2015

In this paper is analyzed a stand-alone solar-wind hybrid system with energy storage in batteries installed on a farm in Romania. Because, after following the system operation, was discovered that the energy demand is not fully covered, two solutions were proposed. The optimization of the system was performed using iHoga, which is a simulation and optimization software based on genetic algorithms. A series of simulations have been conducted, with different configurations of the system, finally obtaining two optimal solutions for the hybrid system. The first solution proposes to increase the number of photovoltaic panels by 10 panels of the same type - System A, and the second solution proposes the installation of a generator - System B. Analyzing the two solutions was noted that in case of the System A, even if the initial investment is higher and produces a lot of excess energy, the total cost over the lifetime of the system is lower then in case of System B. Also, by comparing the two solutions, can be observed a high increase of carbon dioxide emissions in case of System B.
New Assistive Device for People with Motor Disabilities
Authors: Geonea Ionut , Ceccarelli Marco , Copilusi Cristian
Published: July 2015

In this paper, a new mechanism for human leg motion assistance for rehabilitation purposes has been proposed. The structure of human leg and its motions have been used as inspiration for design purposes. A 3D model of the proposed system has been elaborated in Solid Works®, both for design and simulation purposes. It is developed a kinematic model of the mechanism, useful for further design optimization. There has been build an experimental model of the mechanism and they are conducted experimental researches. The result shows that the proposed mechanism performs movements similar to those of a human leg.
A Virtual Reality System for Pre-Planning of Robotic-Assisted Prostate Biopsy
Authors: Gîrbacia Florin , Butnariu Silviu , Voinea Daniel , Tzolea Bogdan , Gîrbacia Teodora , Pîslă Doina
Published: July 2015

Surgical robots for biopsy procedure require pre-operative planning of trajectories prior to be used for needle guiding procedures. Virtual Reality (VR) technologies allow to simulate robotic biopsy procedure and to generate accurate needle trajectories that avoid vital organs. The paper presents a serial robot which can be used for biopsy procedure and a needle trajectory planning software based on VR technologies. A virtual environment has been modelled and simulations for robotic-assisted biopsy of the prostate have been performed.
Infrared Thermography – A Tool for Computer Assisted Research in Rehabilitation Medicine
Authors: Cojocaru Marius Cristian , Cojocaru Ioana Maria , Cojan Carlea Nida Alexandra , Cinteza Delia , Berteanu Mihai
Published: July 2015

Muscle pain can be elicited by any irritation of the nociceptors in the muscle or central sensitization in the central nervous system and represent a challenge for medical as well as for neurological rehabilitation. The most frequently described muscle pain syndromes are myofascial pain syndrome (MPS) and fibromyalgia syndrome (FMS). The use of infrared thermography in rehabilitation medicine for assessment of musculoskeletal disorders is not well documented in the current literature. This study is focused around MPS due to the more localized manifestations of this syndrome and it’s objective is to asses a correlation between the clinical findings, ultrasound examination and the thermal pattern of trigger points.
Characterization of the Thin Films Structures in Subwavelength Regime as Biosensing Materials
Authors: Steigmann R. , Iftimie N. , Savin A.
Published: July 2015

Zinc oxide nanostructured materials, such as films and nanoparticles, could provide a suitable platform for development of high performance biosensing material due to their unique fundamental material properties. This paper presents the characterization of ZnO thin film as biosensing material by metallic strip grating structure (MSG), for the real-time detection. In this work, high quality ZnO films were grown on ITO/glass substrates by vacuum thermal evaporation method. We characterized by X-ray diffraction (XRD) the film crystalline quality and by scanning electron microscopy (SEM) the film morphology.
Preliminary Simulation of the Flow in the Root Canal Using New Irrigation Needle
Authors: Isvoranu Dragoș , Danaila Sterian
Published: July 2015

The main purpose of this paper is to explore the possibility of using a new irrigation device to achieve the goals of root canal preparation for endodontic procedures. A secondary goal is to introduce the never before used physical approach of two-phase, two-component irrigation flow in the root canal. Our simulation results show great efficiency of the irrigation procedure in terms of the irrigant volume fraction and wall shear stress at the wall of the root canal over entire working length.
The Vertical Axis Wind Turbine Efficiency Evaluation by Using the CFD Methods
Authors: Mălăel Ion , Drăgan Valeriu , Vizitiu Georgel
Published: July 2015

In this paper, numerical studies have been conducted in order to evaluate the efficiency of a vertical axis wind turbine by using CFD methods. For these studies, it has been used SIMPLE type pressure-based coupled solver. The complexity and the unsteadiness character of the flow in such a machine, requires the use of unsteady RANS models. To determine the accuracy of the solution obtained by URANS models, this paper makes a comparative analysis with the same case and LES modeling. Analyses were performed with a 2D grid consisting of two regions, a rotor and a stator. The airfoil of the VAWT is a classic NACA0018. Results indicate that the poor accuracy of the URANS CFD method is mainly due to its limitation in the vortex modeling. In general the LES modeling have a better agreement with the experimental results from the wind tunnel.
Characterization of Mg0.8Zn0.2TiO3 Prepared via Liquid Phase Sintering
Authors: Saukani Muhammad , Suasmoro Suasmoro
Published: July 2015

Mg0.8Zn0.2TiO3 powder was synthesized by dissolved method and calcined at 550 °C for 4 hours. The powder exhibited single phase of Mg0.8Zn0.2TiO3 and nano size particle. Sintered pellet samples were prepared by compacting calcined powder which contains 4wt% B2O3 (MZTA), 4wt% Bi2O3 (MZTB) as liquid additive and non-additive sample (MZTC). Phase identification and its percentage were analyzed based on XRD pattern using Rietveld method. The result shows major phase Mg0.8Zn0.2TiO3 ranging from 72.83% for MZTA, 77.9% for MZTB and 82.61% for MZTC. Furthermore, minor phases were identified as Mg2TiO4 and other trace compound Mg3TiO2(BO3)2 for boron additive. Sintered pellet densities were determined by Archimedes method indicate that Bi2O3 additive has the most effective for densification. Microstructure characterization using SEM show that MZTB possesses the largest grain size ≈3.4µm followed by MZTA 2.3µm and MZTC 1.78µm. Dielectrics characterizations within frequency 1 Hz – 32 MHz exhibited space charge polarization characteristic for frequency <1 kHz, however for frequency >1 kHz showed frequency independence of dipolar polarizations and low dielectric loss having εr~17.
The Methanol Response Sensing Properties Using MWCNT-ZnO Composite
Authors: Septiani Ni Luh Wulan , Yuliarto Brian , Iqbal Muhammad , Suyatman Suyatman , Nuruddin Ahmad , Nugraha Nugraha
Published: July 2015

Nano composite MWCNT-ZnO thin films have been synthesized to investigate their methanol sensing properties. MWCNTs have a large surface area, many adsorption site, are sensitive to their chemical environmental, and can be operated at room temperature. While zinc oxide was popular as gas sensor because its easy to fabricate, fast response, easy to control their morphology, and has unique properties depend on their size and shape. In this study, combination of MWCNT and ZnO were made to get their advantages. These nano composites were prepared with weight percent ratio 63:37. MWCNT-ZnO were synthesized by reflux method at 197°C in ethylene glycol. Heat treatment at 300°C were done to obtain powder of nano composite. X-ray diffraction (XRD) and scanning electron microscope were used to investigate the crystal phase and morphology of nano composite. Sensing behavior was investigated at 100°C to 300°C. The best response of 200 ppm methanol occurred at 300°C.
Laser Ablation of Nanoparticles: A Molecular Dynamics Study
Authors: Fahdiran Riser , Urbassek Herbert M.
Published: July 2015

We study laser ablation of nanoparticles (NPs). The interaction of a high-intensity laser pulse with NPs brings the NP into a highly non-equilibrium state. Depending on the energy input from the laser, it will melt and may fragment and evaporate off atoms and clusters. We employ molecular dynamics simulation to study this interaction since thermodynamic properties can be extracted from output data of this simulation. The interatomic interaction is modeled by a Lennard-Jones (LJ) potential. The intensity of the laser is above the ablation threshold. The NP has been chosen to have a spherical shape with diameter 50 s in LJ units. The laser energy is given to the NP instantaneously at the beginning of the simulation and homogenously to all atoms; it corresponds to an energy input of 5.4 e per atom. The simulation is continued up to a time 200 t in LJ units. Temperature-density phase-space trajectories show that the nanoparticle density and temperature strongly decrease after the irradiation. The pressure in the sphere becomes strongly tensile after irradiation. The ablation proceeds by spallation of the irradiated cluster. We provide an analysis of the fragments produced by the ablation of the spherical NP. Our results are contrasted to the case of laser ablation of a thin-film target.
External and Internal Influences in Silicene Monolayer
Authors: Syaputra Marhamni , Arman Wella Sasfan , Purqon Acep , Suprijadi Suprijadi
Published: July 2015

Under external electric field, a free standing silicene monolayer is investigated for the physical and electronic features using the density functional theory with norm-conserving pseudopotentials and pseudo-atomic localized basis functions. It is found that silicene tends to be flat instead of buckled as applying electric field perpendicular to the surface. We observed on some range magnitude of electric field and noticed that there is a monotonic decreasing in number of DOS near the Fermi level showing the possibility of tunable bandgap on silicene. We also found that in this higher magnitude electric field, the Dirac cone is no longer occurring at K-point while the band gap term remains direct. The asymmetry onsite potential between the Si atom at site A and B spoils the degeneracy at the K point by the presence of external or internal influence. In this work, we try to combine those influences by considering Stone Wales (SW) defect and outer z-direction of electric field as internal and external factors respectively. A non-linear correlation of the result is profoundly becoming more effective way in effort to bring remarkable band-gap in silicene monolayer.
Gas Permeation Study of Carbon Tubular Membrane by Manipulating Carbonization Temperature Profile
Authors: Salleh W.N.W. , Sazali Norazlianie , Hasbullah H. , Binti Yusof Norhaniza , Jaafar Juhana , Ismail Ahmad Fauzi
Published: July 2015

Membrane-based separation technology has been widely applied for large-scale industrial CO2 capture due to its lower energy consumption and low pollutant production compared with other conventional techniques. The desirable properties in high performance gas separation membranes involve steps that must carefully be designed and controlled. This study investigates the role of carbonization temperature in the fabrication and performance analysis of carbon membranes prepared from polyimide. A commercial polyimide, Matrimid® 5218, was coated on the surface of ceramic tube to produce supported polymer membrane. The prepared polymer membrane was then carbonized under nitrogen atmosphere to produce supported carbon membrane for CO2/CH4 separation. The resulting carbon tubular membrane separation performance was evaluated using pure gas permeation test. Results showed that the suitable carbonization temperature for Matrimid-based carbon tubular membrane was at 850 °C. The highest selectivity for CO2/CH4 of 82.47 was obtained from carbon tubular membrane prepared at 850 °C.
Thermally Activated Clay to Compete Zeolite for Seawater Desalination
Authors: Wibowo Edy , Rokhmat Mamat , Sutisna Sutisna , Murniati Riri , Khairurrijal Khairurrijal , Abdullah Mikrajuddin
Published: July 2015

We have developed sorbent materials for seawater desalination using different natural materials such as zeolite, clay, soil, coral, and chitosan. The materials were initially activated at temperature range of 200 °C to 600 °C for 3 hours. The greatest salinity reduction was obtained using either activated-zeolite (at 200 °C) or activated-soil (at 600 °C). Surprisingly, thermally activated-soil showed similar efficiency to that of the activated-zeolite. This finding concluded that soil might be a candidate of novel sorbent material to substitute zeolite, the material that is commonly used as sorbent material. Further investigation is in progress to find the optimum method for obtaining the greatest sorption.