bluuebunny/crossref_metadata_2025 huggingface dataset:
How Middle School Principals of Small Rural Schools Address Cyberbullying
Authors: Force Christina M.
Published: April 2016

Cyberbullying affects almost half of the teenagers in America (National Crime Prevention Council [NCPC], 2010). The effects of cyberbullying can be detrimental to teens and may include withdrawal from school activities, illness, depression, eating disorders, or suicidal ideations (Dehue, Bolman, & Vollink, 2008; Mason, 2008). In order to effectively deal with this issue, it is imperative that front-line middle school principals are prepared to address this growing problem. The purpose of this study was to examine how middle school principals of small rural schools address cyberbullying and their beliefs on its effect on the school climate and students. This study examined what middle school principals have experienced with regard to cyberbullying and the ways in which principals have responded to incidences of cyberbullying. A qualitative design using an exploratory multiple case study approach was utilized for this study. The results of this study describe how middle school principals in a small rural setting address cyberbullying and its impact on the school environment.
Narrative Approaches to Conflict Resolution Across Technologically Mediated Landscapes
Authors: Lucić Luka
Published: April 2016

Young migrants across the globe increasingly interact and socialize with culturally diverse others across technologically mediated spaces. Bicultural and transnational development are becoming norms for contemporary youth as new media technology allows them to engage in interactions with diverse others across multiple cultural landscapes. What cultural tools do young migrants use to resolve conflicts with diverse peers across technologically mediated interpersonal interactions? To answer this question 44 individuals (ages 15-20) participated in a quasi-experimental workshop engaging them in the process of sense-making. During the workshop participants wrote projective narratives in response to a vignette depicting text-massage mediated interaction embedded among monocultural and bicultural groups of peers. Quantitative and qualitative data analyses focus on physical, psychological and communicative conflict resolution strategies used in narrative construction. The results indicate that immigrant youth are able to employ and coordinate varied strategies when approaching conflict resolution across culturally diverse landscapes of social interactions.
A Survey Study of Smartphones Behavior in Brunei
Authors: Anshari Muhammad , Alas Yabit , Sabtu Norakmarul Ihsan , Yunus Norazmah
Published: April 2016

The use of smartphones is generating large amounts of data. The term “big data” has become popular in describing a massive data, both structured and unstructured. Big data refers to high volume, high velocity, and high variety. This study used an inductive approach involving the distribution of a questionnaire to gain an understanding of smartphone users' habits in Brunei. Then, the authors identified several concerns that became the focal point of further analysis in the use of smartphones in daily activities. The findings is correlated to the growing of trends of big data application for users' benefit. The finding suggests that there is growing demand from smartphone users could create better services and value through big data application. The authors propose a big data approach that will enable service providers to enhance smartphone users' experiences. Big data application will enable smartphones to become smarter in terms of service and value.
Access Denied
Authors: Pytash Kristine E. , Testa Elisabeth
Published: April 2016

The purpose of this study was to explore three preservice teachers' experiences teaching writing with technology and digital tools during a year-long student teaching experience. Research found that while the three student teachers demonstrated conceptual understandings about the teaching of writing, their use of technology (or lack of) did not always reflect their views. When considering what influenced their transformations as teachers capable and willing to integrate technology into their writing instruction, the school context, particularly the notion of access, significantly shaped their appropriation of pedagogical tools for the teaching of digital writing. In addition, the student teachers were influenced not only by the resources that they had access to, but their perceptions of students' abilities and needs, as well as their own needs and efficacy as novice teachers.
Schools as Driver of Social Innovation and Territorial Development
Authors: Giovannella Carlo
Published: April 2016

This contribution is intended to describe the rationale of a project, in progress, that aims at recovering the centrality of the school through a systemic approach adopting the Design Based Learning as an operative framework of reference capable to foster: (a) the acquisition of an adequate level of LIFE skills by all actors of the learning process (students, teachers, etc.); (b) meaningful collaboration and participation, aimed at achieving social and territorial development; (c) an increase of the social capital. Key issues related to the implementation of the framework and to the training of the teachers expected to manage the process are discussed and recommendation given.
Associating Searching on Search Engines to Subsequent Searching on Sites
Authors: Ortiz-Cordova Adan , Jansen Bernard J.
Published: April 2016

In this research study, the authors investigate the association between external searching, which is searching on a web search engine, and internal searching, which is searching on a website. They classify 295,571 external – internal searches where each search is composed of a search engine query that is submitted to a web search engine and then one or more subsequent queries submitted to a commercial website by the same user. The authors examine 891,453 queries from all searches, of which 295,571 were external search queries and 595,882 were internal search queries. They algorithmically classify all queries into states, and then clustered the searching episodes into major searching configurations and identify the most commonly occurring search patterns for both external, internal, and external-to-internal searching episodes. The research implications of this study are that external sessions and internal sessions must be considered as part of a continuous search episode and that online businesses can leverage external search information to more effectively target potential consumers.
Web Application for User Profiling
Authors: Iggui Taous , Nacer Hassina , Sklab Youcef , Radi Taklit Ait
Published: April 2016

User's profiles play an important role when information systems try to meet their needs. This work presents a novel approach to build user profiles. It is based on information extraction techniques and proceeds by iterative steps. The use of different statistic metrics, Natural Language Processing (NLP) techniques and semantic descriptions (ontologies) in the authors' approach, has provided it with a good precision degree when extracting information from texts. This has been demonstrated by an application prototype which is an automatic user profile constructor, using the texts of emails job applications (E recruitment field).
ADM-Based Migration from JAVA Swing to RIA Applications
Authors: Mbarki Samir , Laaz Naziha , Gotti Sara , Gotti Zineb
Published: April 2016

Companies are investing a lot of resources and effort for migrating their legacy applications and adapting them with the rapid technological changes. For this reason, the authors are interested in the modernization of desktop applications developed in Java Swing to Web 2.0 applications. Therefore, an ADM approach is applied in order to develop a tool named FlexMigration allowing automatic reverse engineering of Swing GUI to obtain a RIA GUI. The usefulness of this tool is the automation of the migration process with the extraction of the actions encapsulated in possible anonymous classes. As an illustration, they present along this paper a reengineering of a small legacy chat application. The authors explain its migration process to generate a similar Flex Graphical User Interface.
Service and Billing Management Method for ICT Services
Authors: Iwashita Motoi , Tanimoto Shigeaki
Published: April 2016

Information and communication technology (ICT) including broadband networks, cloud computing, a variety of mobile devices, point-card systems, and “virtual coins” can induce complicated situations concerning customer management. In particular, billing management is very critical, and it is thus necessary to establish a billing-management method that can quickly adjust to changes in the environment. The first requirement is managing the relationships between services, payments, and settlements so as to assure the payment method and service provision and payment routes. Therefore, a business model design method, established from the viewpoint of service, cash flow, and settlement to strategically adjust to changes in the environment, is described herein. In addition, a procedure for managing the connection paths is proposed to efficiently construct the relationship between services, payments, and settlements.
A Method Based on Self-Study Log Information for Improving Effectiveness of Classroom Component in Flipped Classroom Approach
Authors: Umezawa Katsuyuki , Ishida Takashi , Aramoto Michitaka , Kobayashi Manabu , Nakazawa Makoto , Hirasawa Shigeichi
Published: April 2016

The flipped classroom approach has recently begun to attract attention. In a flipped classroom, the conventional roles of classroom and homework are reversed: students study on their own using digital teaching materials or e-learning prior to class and then apply their learning in classroom activities. The authors have developed a method for improving the effectiveness of the classroom component: the students in a class are grouped on the basis of the time they spent studying (as recorded in their self-study logs) and their degree of understanding (as revealed by a self-study achievement test), and a different learning model is used for each group to improve their degree of understanding. Although they were unable to find a meaningful statistical difference in the test scores obtained in an experiment using one class of 34 students, there was a notable difference in the way questions were answered. The results of a free-description questionnaire indicate that the group learning encourages active learning.
Geocoding Tweets Approach Based on Conceptual Representations in the Context of the Knowledge Society
Authors: Escamilla Imelda , Torres-Ruiz Miguel , Moreno-Ibarra Marco , Quintero Rolando , Guzmán Giovanni , Luna-Soto Vladimir
Published: April 2016

In this paper, an approach to geocode tweets published in Spanish is proposed. The tweets are related to traffic events within an urban context of the Mexico City. They are generated by a particular phenomenon for knowing the behavior of the involved geographic entities. In order to disambiguate and verify the consistency of information, an application ontology was defined. Thus, the core goal is to identify location as well as spatial relationships between entities presented in the events, using semantic and spatial analysis of the collected dataset. In consequence, a visualization method for presenting the results was also proposed. The paper describes the methodology for enabling the discovery of spatial patterns within traffic tweets and provides useful information to make timely decisions and contribute in the context of Knowledge Society.
Using a Dialogue Manager to Improve Semantic Web Search
Authors: Melo Dora , Rodrigues Irene Pimenta , Nogueira Vitor Beires
Published: April 2016

Question Answering systems that resort to the Semantic Web as a knowledge base can go well beyond the usual matching words in documents and, preferably, find a precise answer, without requiring user help to interpret the documents returned. In this paper, the authors introduce a Dialogue Manager that, through the analysis of the question and the type of expected answer, provides accurate answers to the questions posed in Natural Language. The Dialogue Manager not only represents the semantics of the questions, but also represents the structure of the discourse, including the user intentions and the questions context, adding the ability to deal with multiple answers and providing justified answers. The authors' system performance is evaluated by comparing with similar question answering systems. Although the test suite is slight dimension, the results obtained are very promising.
Experimental Investigation on the Impact of Distorted Signal on Synthetic Jet
Authors: Gil Paweł
Published: April 2016

Effective techniques for cooling electronic devices must deal with increasing heat loads associated with higher heat flux density. Many conventional cooling techniques like fan are reaching the limits of their effectiveness and shape. The novel method of heat transfer enhancement is synthetic jet.
In this paper experimental results are presented. Synthetic jet actuator consist of STX 6.5 inch speaker installed in metacrylate chamber with circular orifice. The actuator was powered with signal from amplifier. The signal consist of basic sinusoidal function and THD noise added with some amplitude. The root mean square of signal voltage was constant 4V. The properties of synthetic jet were measured using constant temperature thermo-anemometer. Instantaneous velocity of air was measured in the orifice center and compared with input signal. Additional RMS and average velocity of air were measured.
Measurement revealed that input signal of synthetic jet generator can contain some noise without effect on RMS and average velocity of air in the orifice. The THD less than 1% does not cause negative effect on synthetic jet fluid velocity.
Experimental Investigations inside the Wind Tunnel at the University of Stralsund
Authors: Panten Thomas , Meironke Heiko
Published: April 2016

In this paper the wind tunnel at the University of Applied Sciences Stralsund and few construction details as well as the calibration of the nozzle are presented. Furthermore some approaches to visualization and measurement of velocity fields of a simple body of vehicle are shown. The wake structure behind of simple car models was investigated experimentally using Particle Image Velocimetry (PIV). Furthermore the visualization of flow field by the fog probe systems supports the evaluation of the flow and drag behavior.
New Kinematic Systems in Single-Sided Lapping and their Influence on Lap Wear
Authors: Barylski Adam , Piotrowski Norbert
Published: April 2016

Previous studies on one-sided lapping allow to state that not only parameters of lapping elements (i.e. properties of workpiece, abrasive grains and lapping plate) impact on a lapping efficiency. Influential are also kinematics and dynamics of the process. It is crucial to control an average velocity of lapping (v), a distribution of tangential acceleration (at), a nominal pressure (p), a lapping time (t) and disposal of workpiece in separator.Based on kinematics equations and the tribological models, the dimensionless distribution of the material removal volume and the trajectories of abrasive grains cutting on the lap were numerically simulated. Obtained information about excessive wear on lapping plate was the starting point to work out non-standard, single-plate lapping systems.In this paper ideas of unconventional lapping systems were presented. After numerous simulations and careful analysis it was observed, that the most desirable system is radial lapping system. It was point out that other systems are not very different from the standard kinematic system. Generated trajectories of an abrasive grain were almost identical. What is more, effects of kinematical parameters on the trajectories, velocities and accelerations observed in radial lapping system are shown.
Calculation Methodology of Defrosting Room for Rail Cars
Authors: Zapałowicz Zbigniew , Biały Lech
Published: April 2016

Enhancement of efficiency of defrosting process of freight cars is a very important problem in any of countries characterized by severe or temperate climates. In the present article, the calculation methodology of air parameters, that is of energy carrier, in defrosting room is presented. Heat between the particular media is transferred only by convection. Changes of volumetric flow rates and heat fluxes in characteristic points of defrosting room in the function of volumetric flow rate of supplied air are presented in the work.
Performance of a Plate Heat Exchanger Operated with Water-Al2O3 Nanofluid
Authors: Cieśliński Janusz T. , Fiuk Artur , Miciak Wojciech , Siemieńczuk Bartłomiej
Published: April 2016

This study is focused on experimental investigation of a selected type of brazed plate heat exchanger (PHEx). The main aim of the paper was to experimentally check the ability of nanofluids to enhance the performance of PHEx. A typical water-Al2O3 nanofluid was tested and compared to that of the base fluid, i.e. water. Nanoparticles were tested at the concentration of 0.1% and 1% by weight. Impact of the 1 day and 3 days break of operation of the tested PHEx on its performance was of particular interest. Pressure drop in all runs was measured as well. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. It was observed, that addition of nanoparticles resulted in deterioration of an overall heat transfer coefficient for the selected PHEx and tested conditions, i.e. temperature range and Reynolds number. Moreover, substantial increase of pressure drop was recorded after each break of operation of the tested PHEx.
Influence of Nanoparticle Concentration on Convective Heat Transfer of Water-Al2O3 Nanofluids inside Horizontal Tubes
Authors: Cieśliński Janusz T. , Kozak Przemysław
Published: April 2016

In contrast to the very rich literature on modeling and the determination of the thermal conductivity of nanofluids the forced convection data are limited. This work presents preliminary results of the experimental investigation of the forced convection heat transfer of water-Al2O3 nanofluids inside stainless steel tube with 8 mm internal diameter and 2000 mm length. Nanoparticles were tested at the concentrations of 0.01%, 0.1%, 1% and 5% by weight and the Reynolds number range encompasses laminar as well as turbulent flows.
The Experimental Investigation of the Biomass-Fired ORC System with a Radial Microturbine
Authors: Kaczmarczyk Tomasz Z. , Żywica Grzegorz , Ihnatowicz Eugeniusz
Published: April 2016

The paper presents the results of experimental investigation of the ORC system with a droplet separator (which was used to improve the quality of working medium vapour), a radial microturbine and a multi-fuel boiler. The research aimed at verifying the correctness of prototype microturbine performance in the ORC installation, equipped with a heat source in the form of the multi-fuel boiler. During these tests, a detailed assessment of the functioning of the microturbine and the boiler has been devoted more attention. The paper contains the characteristics of the heat exchangers installation that were obtained for the ORC system variant using a regenerative cycle. The multi-fuel boiler was fired with biomass (wood pellets). Two series of measurements were conducted for various flow rates and several selected temperatures of the working medium, glycol solution and thermal oil. On the basis of research carried out on the ORC with a radial microturbine, one can say that, physicochemical parameters of the HFE7100 medium obtained during the first measuring series, were as follows: temperature at the microturbine inlet 158.9 °C, pressure at the microturbine inlet 9.66 bar, flow rate 178.9 g/s at the microturbine discharge pressure of 1.75 bar. The second series of measurements gave the following results: temperature at the microturbine inlet 163.2 °C, pressure at the microturbine inlet 9.86 bar, flow rate 179.2 g/s at the microturbine discharge pressure of 1.88 bar. The maximum electrical power generated with the use of radial microturbine working in the regenerative ORC system reached about 1150 We.
Proportional-Derivative and Model-Based Controllers for Control of a Variable Mass Manipulator
Authors: Lipiński Krzysztof
Published: April 2016

In the paper,numerical analysis of dynamics of a variable mass manipulator is presented. A revolute joints composed manipulator is considered. Payload of the gripper is considered as the only element characterized by unknown value of its mass (variable between subsequent operations). As in other cases of the revolute joints composed manipulators, its behaviour dependents significantly on the pose of the manipulator. When the manipulator is driven over a larger operating range, nonlinear terms can be observed in the equations, and linear controller does not ensure satisfactory its performance. Thus, nonlinear control technique is employed. To ensure such non-linear control, nonlinear models of the plant are introduced in the controller. Initially, there is an open-loop feedforward model-based controller used to enforce the manipulator to follow the required paths. Work of the proposed configuration is tested numerically. To deal with it, a numerical model of the manipulator is prepared and rules of multibody modelling are used for it. Two identical models (equations) are implemented in two separate blocks of the model. In the controller block, primary set of parameters of the robot structure is introduced. As the actual gaol is to observe effects of the incorrect identification of the payload masses, the plant (the controlled object) model may not be described by identical values of their masses in the performed tests. As a result, significant path errors are observed during simulations. To eliminate these errors, the controller model is enlarged. A feedback loop is accepted and a proportional-derivative controller is considered in this feedback part. Subsequently, collaboration between these feedforward and feedback blocks is tested. This collaboration runs well (error of the realised path is reduced). However, intensive work of the feedback controller is non-required in the considered application. Possibility of mass identification is tested. Performed tests proofed that signal of the proportional-derivative controller is a useful data base for the required identification process. A short run of a trial path is performed at beginning of the motion. PD signal obtained during such test motion are collected. They allow us to identify the mass of the payload and to improve data in the model-based controller. Thanks of it, the feedback control signal is reduced and realisation of the required path is acceptable.
Analysis of Heat Transfer and Fluid Flow in Two-Phase Thermosyphon Loop with Minichannels
Authors: Bieliński Henryk , Mikielewicz Jaroslaw
Published: April 2016

The present paper offers an analysis of heat transfer and fluid flow in two phase thermosyphon loop with minichannels. A one-dimensional model of two-phase flow and heat transfer in a closed thermosyphon loop with minichannels was examined. The created general model is based on mass, momentum, and energy balances in the evaporators, rising tube, condensers and the falling tube. The separate two-phase flow model is used in calculations. The numerical results obtained for the selected heater and cooler using the general model of thermosyphon loop indicate that the mass flux increases with increasing length of the heated section and decreases with increasing length of the cooled section of the loop. It was found that the heat transfer coefficient for flow boiling and flow condensation in the steady state increases with increasing heat flux in the heater and cooler with minichannels, respectively. The design and configuration of heaters and coolers has a considerable impact on the efficiency of thermosyphon loop. These factors make it possible to optimize the computer processor cooling.
Using of Ferrous Chloride in Anaerobic Digestion of a Substrate with High Sulphur Content
Authors: Hutňan Miroslav , Chávez-Fuentes Juan José , Czölderová Marianna
Published: April 2016

Possibilities of anaerobic processing of substrates rich in sulphur were studied. High concentrations of sulphur cause problems when contained in biogas, as well as inhibition by sulphides in anaerobic processes. The impact of ferrous chloride on anaerobic processes, directly dosed to the anaerobic reactor was studied. This sulphur removal method is commonly known, though the objective of our study was to identify problems when it is applied on substrates rich in sulphur. Waste biomass from cystine production was used as substrate, which is produced in large quantities (17000 t/y) by Biotika, a.s. Slovenská Ľupča and requires processing; sulphur content range from 4 up to 5 % in the biomass. Specific biogas production was 0.410 m3/kg COD i.e. 0.737 m3/kg VSS, while 77 % sulphide inhibition occurred after several dose repetitions. Inhibition decreased to 25.4 % during long-term processing of cystine biomass in a mixed anaerobic reactor. Ferrous chloride dosing, however, resulted in high excess sludge generation, lower organic content in the sludge and high concentration of dissolved inorganic salts. These factors may lead to secondary problems in long-term processing of cystine biomass.
SO2 Measurement with Sorption - Cumulative and Ultraviolet Fluorescent Method near Nováky Power Plant
Authors: Pokrývková Jozefína , Fuska Jakub , Bárek Viliam
Published: April 2016

Satisfying of increasing demands of society has often resulted in uncontrolled discharges of harmful substances into the atmosphere. The situation is gradually improving over the past 50 years, but the environmental impact is still evident and it must be monitored and evaluated. Reduction of emissions released into the atmosphere and reduction of air pollution impact on the Earth surface occurs due to development of new methods and technologies in the industry and legislation. This paper deals with the possibilities of the two methods of the SO2 concentration measurements - sorption - cumulative and ultraviolet fluorescent method at the location of the power plant Novaky. In the imission area is built automated measuring station (AMS) Oslany (operated by ENVITECH, managed by Slovak Hydrometeorological Institute Bratislava) as the measure of the total concentration of the pollutant. The research have shown that the maximum concentration detected in this area reached up to 64.46 µg.m-3 of SO2
Measurement Technique for the Flood Barriers Deformation Determination
Authors: Kopunec Tomáš , Vajsábel Michal , Pavlásek Peter , Koval Martin , Ďuriš Stanislav , Šooš Ľubomír
Published: April 2016

Changes in the climate over the past decades have caused weather extremes that bring numerous unwanted phenomena. Many of these irregularities cause unusually high and low temperatures, intense droughts and devastating floods. All of the listed natural disasters caused by weather extremes affect a wide range of fields which are crucial for our everyday life and its quality. The most affected areas are health and safety, agriculture, industry, transportation. It is therefore evident that the effect of extreme weather in any form can bring not only financial loses, but also a loss of human lives. Based on these facts it is of great interest that the effects of these natural forces are minimised or totally eliminated. This paper deals with the performance of a newly designed mobile flood barrier in real simulated field test conditions. Construction of the barriers was designed solely by the Slovak University of Technology at its Faculty of Mechanical Engineering with the intention of providing effective, economic and safe flood barriers system with a short assembly time. The undertaken testing was focused on the performance of the flood barriers under static pressure by the deflection measurements. The testing consisted of the following steps: experiment design, on sight mounting and fine-tuning of the whole measuring apparatus and evaluation of the gathered data. To simulate real conditions which the barrier will experience during its use, a life size model of the flood barrier segment was constructed and tested. The measurement setup, measurement procedures, the outcomes of the deformation testing together with the resulting deflection model are presented in the following pages of this paper.
Development of a Modular Flood Barrier Concept Made from Recycled Plastic
Authors: Šooš Ľubomír , Ondruška Juraj , Kovač Pavel , Čačko Viliam
Published: April 2016

This contribution describes developments in the area of plastic recycling aimed at the reuse of waste materials for the manufacture of a useful product. Throughout development of the concept “modular flood barrier structure”, the recovery of plastic materials was assessed, primarily, plastic waste from automobiles and industry. The investigators filed a utility model application, no. SK 5847 Y12, entitled “Modular flood barrier structure”. Terms of the type and composition of source material, polypropylene (PP) and polyethylene (PE) were the materials chosen. The article describes the theoretical analysis of the proposed barriers as a starting point for a design and technological design.
Optimization of Secondary Air Distribution in Biomass Boiler by CFD Analysis
Authors: Lisý Martin , Pospíšil Jiří , Štelcl Otakar , Špilaček Michal
Published: April 2016

This paper deals with a use of CFD modelling for optimization of supply of secondary combustion air in the two-chamber biomass boiler combusting very wet biomass (capacity ca. 200 kW). Objective of the analyse is to observe the impact of diameter of a secondary air supply pipe and air flow velocity on mixing of the secondary air with flue gas in the combustion chamber. The numerical model of the experimental boiler was build up for subsequent utilizing of CFD computation based on finite element method. The commercial code STAR-CD was used for carried out parametrical studies. Series of calculations were carried out for four different diameters of air distribution pipes and for 3 different air velocities in distribution orifice. Quality of air dispersion in flue gas flow was assessed in the vertical cross section lead in the end of the combustion chamber. The results of calculation were verified on the experimental installation of the boiler. Influence of secondary air mixing on emission production was measured and analysed. Emissions of pollutants for recommended air distribution comply with emission limits stipulated in the most stringent class 5 according to ČSN-EN 303-5 as well as with emission limits under Regulation No. 405/2012 Sb.
Steam Biomass Gasification - Effect of Temperature
Authors: Baláš Marek , Lisý Martin , Pospíšil Jiří
Published: April 2016

Gasification is one of the technologies for utilization of biomass. Gasification is a transformation process that converts solid fuels into gaseous fuels. The gaseous fuel may be subsequently applied in other technologies with all the benefits that gaseous fuels provide. The principle of biomass gasification is a common knowledge. It is thermochemical decomposition oof the fuel in presence of gasification agent. Heat from the endothermic reaction is obtained by a partial combustion of the fuel (autothermal gasification) or the heat is supplied into a gasifier from the outside (allothermal gasification). Oxygen for the partial combustion is supplied in the gasification medium. Quality, composition and amount of the producer gas depend on many factors which include type of the gasifier, operating temperature and pressure, fuel properties (moisture content) and type and amount of gasification medium. Commonly, air, steam and oxygen and their combinations are used as a gasification medium. Every kind of gasification agents has its significant advantages and disadvantages.Research and analysis of the gasification process must pay special attention to all operating parameters which affect quality and amount of the producer gas that is the efficiency of the conversion itself. Composition of the producer gas, calorific value, and content and composition of impurities are especially observed as these are the basic characteristics directly affecting subsequent application of the gas. Steam addition has a significant impact on gas composition. Steam decomposition into hydrogen and oxygen, and their subsequent reactions increases amount of combustibles, hydrogen, methane and other hydrocarbons. Steam addition in the gasification also affects amount and composition of tar and has a negative impact on heat balance.Energy Institute at the Brno University of Technology has a long tradition in research of biomass gasification in atmospheric fluidized bed reactors. Air was used as a gasification medium. This paper describes our experience with gasification using a mixture of air and steam. We analysed the whole process and in this paper we wish to describe the impact of temperature on outputs of the process, especially temperature of leaving steam and temperature of gasification reactions.
Biogas Production Using Anaerobic Digestion of Industrial Waste
Authors: Gaduš Ján , Giertl Tomáš , Kažimírová Viera
Published: April 2016

In the paper experiments and theory of biogas production using industrial waste from paper production as a co-substrate are described. The main aim of the experiments was to evaluate the sensitivity and applicability of the biochemical conversion using the anaerobic digestion of the mixed biomass in the pilot fermentor (5 m3), where the mesophillic temperature was maintained. It was in parallel operation with a large scale fermentor (100 m3). The research was carried out at the biogas plant in Kolíňany, which is a demonstration facility of the Slovak University of Agriculture in Nitra. The experiments proved that the waste arising from the paper production can be used in case of its appropriate dosing as an input substrate for biogas production, and thus it can improve the economic balance of the biogas plant.
Electrical Resistivity of Cement Based Materials
Authors: Wan Masra Sharifah Masniah , Sutan Norsuzailina Mohamed , Keran A.K. , Matudin N.D.
Published: April 2016

Electrical resistivity (ER) of cement based materials (CBM) is an important measurement that indirectly relates to the durability of CBM. This study investigates the correlation between ER of CBM namely concrete with water-to-cement (w/c). As one of CBM hydration parameters w/c is an important parameter that contributes to variations of ER. The results of this study showed that different w/c can be used as indication for the setting characteristics as well as the pore structure of the concrete. ER is obtained by applying current into the concrete and measuring the response voltage during concrete hydration period of 28 days. Two aspects were also being considered in this study: (i) test specimen size and (ii) spacing between the probes. Results show the direct correlation between ER and test specimen sizes and spacing between the probes.
Numerical Investigation of Rotational Speed on Pump as Turbine for Microhydro Applications
Authors: Ismail Mohd Azlan , Othman Al Khalid , Zen Hushairi
Published: April 2016

Pump as Turbine (PAT) always has been a favourable solution to generate electricity in rural areas when there is a potential microhydro site. Such systems have lower capital cost, and they are easier to maintain than commercially-available microhydro turbines. Normally, PAT is designed to run at a rated rotational speed so it can directly couple with an induction generator in order to match the synchronous speed. In an actual scenario, the PAT’s rotational speed changes and fluctuates with respect to flow rate due to the absence of a hydraulic control mechanism. It is essential to understand how the PAT behaves under different rotational speeds in order to design good microhydro systems. The aim of this study was to conduct simulation analysis of the effect of rotational speed on PAT’s performance curve over a range of flow rates. ANSYS CFX software was used as the Computational Fluid Dynamic (CFD) simulation tool in this study. Three distinct flow domains was modelled by Computer Aided Design (CAD) software and assembled as the computational fluid domains. Mesh independence analysis and convergence criteria were set to ensure the accuracy of the model. The torque generated by the impeller was collected from the simulation data and presented in the PAT performance curve. It was observed that the pressure head and torque generated increased at higher rotational speeds, thus maintaining the efficiency value. The results showed that the efficiency of the PAT was maintained around 76.5% for rotational speeds between 1350 to 1650 RPM, but the best efficiency point shifted to lower flow rate for lower rotational speed. The outcomes of this study will be useful for turbomachinery researchers, microhydro users, and project engineers for predicting the PAT performance for designing microhydro systems.
Design and Analysis of CMOS Linear Feedback Shift Registers for Low Power Application
Authors: bin Rosly Hasrul Nisham , bin Ibne Reaz Mamun , Kamal Noorfazila , Hashim Fazida Hanim
Published: April 2016

Chip manufacturing technologies have been a key to the growth in all electronics devices over the past decade, bringing added convenience and accessibility through advantages in cost, size, and power consumption. Using recent CMOS technology, LFSR is implemented until layout level which develops low power application. One of the most frequent uses of a LFSR inside a FPGA is as a counter. Using a LFSR instead of a binary counter can increase the clock rate considerably due to the low routing resource required to produce the next state logic. This paper explores the LFSR using different architecture in a 0.18μm CMOS technology. There are 3 type architecture implemented into LFSR which is NAND gates, pass transistor and transmission gates. Those LFSR are compare in term of CMOS layout, hardware implementation and power consumption using Mentor Graphics tools. Thus, it provides analysis of LFSR for low power application in CMOS VLSI.
Guided Wave Matching Layer Using a Quarter of Wavelength Technique
Authors: Ilham H.M. , Salim M.N. , Jenal R.B. , Hayashi T.
Published: April 2016

Matching layers of acoustic impedance are intensively studied in ultrasonic transducers for the efficiency of wave transmission. Large impedance mismatch between the active element of piezo and parent material in long range ultrasonic is also expected to have the similar affects on the ratio of the transmitted and reflected waves which can cause high reflection at the interface that result acoustic wave ringing and indicate low transmitted energy for inspection over large areas. This simulation study present analysis of Lamb wave propagation through a single matching layer from a piezoelectric transducers. It explains transmitted waves into aluminum plate using different materials of matching plates at thickness of quarter wavelength. Four matching plates with close to the computed value of acoustic impedance had been used in FEM simulations to study effect of the matching layers on the transmitted Lamb wave in aluminum plate. The results indicated slightly different phenomenon of multiple wave reflections from the transmitted S0 and A0 modes at boundary of the matching layer.
Characterization of Steel Fiber Reinforced Acrylic Emulsion Polymer Modified Concrete (SFRPMC) through X-Ray Diffraction (XRD) Analysis
Authors: Hazimmah D.S. , Muthusamy Khairunisa
Published: April 2016

The results show the effect of polymer modification on the behavior of Ca (OH)2 in steel fiber reinforced concrete. The polymer modified concrete were prepared using acrylic emulsion polymer at various polymer-cement ratios; they were tested for mechanical strengths, moulded into specimens and cured. The cured specimens were subjected for compressive strength, flexural strength, splitting tensile strength and modulus of elasticity. The small specimens that moulded were subjected to X-ray diffraction (XRD). From the test results, it is concluded that formation of Ca (OH)2 in the polymer modified concrete reinforced with steel fiber is reduced possibly because of the absorption of Ca (OH)2 on polymer films formed in the concrete. The extent of reduction in the quantity of Ca (OH)2 depends upon the polymer-cement ratio, polymer type or both. Generally SFRPMC of mix 43 with 2.5% polymer-cement ratio were found to be more effective than other SFRPMC with 1.0% and 4.0% acrylic emulsion polymer in reducing the quantity of Ca (OH)2 in SFRPMC. The cement modifiers did not cause any detrimental effect on the degree of hydration as in SFRPMC therefore, does not provide a proper means for predicting their degree of hydration.
The Influence of Barium Compounds on the Formation of Portland Cement Clinker
Authors: Zezulová Anežka , Staněk Theodor , Opravil Tomáš
Published: April 2016

Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present article examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulphate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point counting method), as well as the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS.
Fluorescence Analysis of Cu(II), Pb(II) and Hg(II) Ion Binding to Humic and Fulvic Acids
Authors: Enev Vojtěch , Türkeová Irena , Szewieczková Jana , Doskocil Leos , Klučáková Martina
Published: April 2016

Abstract. The aim of this work was to study molecular and quantitative aspects of metal ion binding to humic substances (HS). The object of our study was characterization of two standards of humic substances (Elliott Soil standard HA 1S102H and Elliott Soil standard FA 2S102F). All samples of IHSS standards HS were characterized by elemental analysis (EA), ultraviolet-visible spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR) and steady-state fluorescence spectroscopy. Chemical parameters on the complexation of Cu (II), Pb(II) and Hg(II), including the conditional stability constants and the percentage of fluorophores participating in the complexation, were estimated by the modified Stern–Volmer equation. The stability constants (log Ka) of Me(II)–ESHS complexes range from 3.70 to 5.15 in the order: Hg–ESHA>Cu–ESHA>Pb–ESHA>Cu–ESFA>Pb–ESFA. With respect to the ESHA, ESFA, which showed the smallest contents of O-containing functional groups (e.g. hydroxyl, carbonyl, ester, especially carboxyl groups on the aromatic ring) and the lowest humification degree, the ESFA was characterized by much smaller stability constants. Our findings suggest that soil HS belongs to class of important organic ligands for complexation with heavy metal ions and may significantly affect the chemical forms, mobility, bioavailability and ecotoxicity of heavy metals in the soil environment.
Preparation and Utilization of Alumina Oxide Membranes for Sensor Devices
Authors: Kynclová Hana , Smilek Jiří , Sedlacek Petr , Prášek Jan , Klučáková Martina , Hubálek Jaromir
Published: April 2016

This work describes preparation process of free-standing alumina membranes used in sensor devices for separation or purification (increased selectivity, and sensitivity) purposes. Nanoporous alumina membranes were prepared using anodic oxidation of aluminium foil in two types of acidic electrolytes and characterized using scanning electron microscopy. Membranes with pore diameters of 90 nm and 30 nm and thicknesses of 115 µm and 163 µm respectively were obtained. Fabrication of membranes with different post-treatment was also done. In this post-treatment process, etching of non-anodized aluminium and opening of barrier layer were replaced with application of reversible potential with equal magnitude as anodization voltage.
Organic Sensor for Cardiomyocytes Research
Authors: Salyk Ota , Omasta Lukáš , Vala Martin , Weiter Martin
Published: April 2016

Organic electronic devices offer a convenient solution for bioelectronic sensor applications due to the biocompatibility of organic semiconductors and biologic tissues. So-called biosensors can convert electrochemical processes connected to cell membranes into electronic signals. A matrix of such biosensors can simultaneously scan a number of biological samples as well as living tissue in the body. The core of the device is a transistor, today mostly OECT (Organic Electro Chemical Transistor) fabricated by thin film or printing technique from semiconducting biocompatible polymer PEDOT:PSS (poly(3, 4-ethylenedioxythiophene) polystyrene sulfonate). Such transistors were printed both by inkjet and screen-printing technique and their main characteristics are presented.
Removal of Copper (II) Ions from Aqua Growth Medium by Red Yeast
Authors: Breierova Emília , Čertík Milan , Marova Ivana
Published: April 2016

Copper is a natural fungicide and is the active component of various pesticides. We detected uptake of higher concentration of the copper ions and responses to this stress in combination with presence hydrogen peroxide as a source of free radicals were studied on the three red yeast strains of species Rhodotorula glutinis (two strains) and Sporobolomyces roseus (one strain). The maximum Cu sorption was observed at the cells of strain Rhodotorula glutinis CCY 20-2-33 (25,18 mg/g dry weight) and at their exopolymers which accumulated the amount 10.22 mg/g dry weight. The remaining copper was sorbed onto the fibrillar part of cell wall (3.75 mg/g dry weight). The presence peroxide (oxidative stress) in cultivation medium decreased of the toleration of yeasts to Cu2+ ions and cells were able to take up less of about 17 % (from 3mM on 2,5 mM), although total uptake was lower about 11.01-15.96 %. We found that the strains of Rhodotorula glutinis are able to uptake about 44 % more copper ions (25.18-24.32 mg/g dry weight) in compared with strain of Sporobolomyces roseus (16.92 dry weight). However, the addition of peroxide into the cultivation medium the addition of affecting trade changes by reduce of the ability to uptake Cu2+ ions. The exopolymers and fibrillar part of cell wall these yeast were used as biopolymers with high sorption ability for metals.
Mechanisms of Macro-Pores Origin in the MDF Composites Fabrication
Authors: Másilko Jiří , Šoukal František , Žůrová Marcela , Koplík Jan , Havlica Jaromír
Published: April 2016

Paper deals with the description of the MDF composite microstructure and the possible emergence of macro-pores. MDF composites show enhanced mechanical properties, especially flexural strength. Where, the flexural strength can be associated with the elimination of critical cracks in the material. One of the steps of production of MDF composites is high-shear mixing, that just helps to achieve defect-free structure. The primary aim of this work is to specifically describe the origin of the macro-pores in the structure of MDF composites. The secondary one is to find appropriate setup for high-shear mixing equipment in order to eliminate main macro-pores (shear speed, distance between the rollers etc.).