bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of SCADA Systems in Control of Green Sands Properties
Authors: Ignaszak Z. , Sika R. , Perzyk M. , Kochański A. , Kozłowski J.
Published: January 2016

The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition) systems, used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate) and water. The studies conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS - Automatic Sand Measurement System and MCM – Main Control Module) and after the implementation. Results of measurement of selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically in laboratory.
Structural Aspects of Remelting of the AZ91 Magnesium Alloy Surface Layer
Authors: Iwaszko J. , Strzelecka M.
Published: January 2016

In this study, modification of the AZ91 magnesium alloy surface layer with a CO2 continuous wave operation laser has been taken on. The extent and character of structural changes generated in the surface layer of the material was being assessed on the basis of both macro- and microscopy investigations, and the EDX analysis. Considerable changes in the structure of the AZ91 alloy surface layer and the morphology of phases have been found. The remelting processing was accompanied by a strong refinement of the structure and a more uniform distribution of individual phases. The conducted investigations showed that the remelting zone dimensions are a result of the process parameters, and that they can be controlled by an appropriate combination of basic remelting parameters, i.e. the laser power, the distance from the sample surface, and the scanning rate. The investigations and the obtained results revealed the possibility of an effective modification of the AZ91 magnesium alloy surface layer in the process of remelting carried out with a CO2 laser beam.
Effect of the Surface Layer of Iron Casting on the Growth of Protective Coating During Hot-Dip Galvanizing
Authors: Kopyciński D. , Guzik E. , Szczęsny A.
Published: January 2016

The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating.
Thermal Properties of Foundry Mould Made of Used Green Sand
Authors: Krajewski P.K. , Piwowarski G. , Buraś J.
Published: January 2016

The paper presents results of measuring heat diffusivity and thermal conductivity coefficients of used green foundry sand in temperature range ambient − 600 °C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that the obtained relationships are complex and that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured and solidified casting.
Modeling of Melting and Resolidification in Domain of Metal Film Subjected to a Laser Pulse
Authors: Majchrzak E. , Mochnacki B.
Published: January 2016

Thermal processes in domain of thin metal film subjected to a strong laser pulse are discussed. The heating of domain considered causes the melting and next (after the end of beam impact) the resolidification of metal superficial layer. The laser action (a time dependent bell-type function) is taken into account by the introduction of internal heat source in the energy equation describing the heat transfer in domain of metal film. Taking into account the extremely short duration, extreme temperature gradients and very small geometrical dimensions of the domain considered, the mathematical model of the process is based on the dual phase lag equation supplemented by the suitable boundary-initial conditions. To model the phase transitions the artificial mushy zone is introduced. At the stage of numerical modeling the Control Volume Method is used. The examples of computations are also presented.
Computer-Aided Design of Steel Casting Taking into Account the Feeding Ability
Authors: Polyakov S. , Kuzyi O. , Korotschenko A. , Korovin V. , Bast J.
Published: January 2016

A new Computer-Aided Design approach is introduced for design of steel castings taking into account the feeding ability in sand moulds. This approach uses the geometrical modeling by a CAD-program, in which the modul “Castdesigner” is implemented, which includes the feeding models of steel castings. Furthermore, the feeding ability is guaranteed immediately during the design by an interactive geometry change of the casting cross section, so that a directional feeding of the solidifying casting from the installed risers is assured.
Low Cycle Mechanical and Fatigue Properties of AlZnMgCu Alloy
Authors: Pysz S. , Czekaj E. , Żuczek R. , Maj M. , Piekło J.
Published: January 2016

The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the 7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue properties support the thesis adopted, while the design works further confirm these assumptions.
Effect of Sand Wetting on Physically Hardened Moulding Sands Containing a Selected Inorganic Binder. Part 1
Authors: Stachowicz M. , Granat K. , Pałyga Ł.
Published: January 2016

In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45 GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by microwave heating.
Sedimentation of Copper Droplets after their Coagulation and Growth. Laboratory Scale
Authors: Wołczyński W. , Bydałek A.W.
Published: January 2016

The suspension of copper droplets in the slag is considered. The copper/slug suspension is delivered as the product from the direct-to-blister process which is applied in the KGHM – Polska Miedź (Polish Copper) S.A. factory. The droplets / slag suspension was treated by a special set of reagents (patented by the authors) to improve the coagulation process. On the other hand, the observations are made to estimate if the melting / reduction process in the furnace is sufficiently effective to avoid a remaining of carbon in the copper droplets. The coagulation process was carried out in the crucible (laboratory scale). However, conditions imposed to the coagulation / solidification process in the laboratory scale were to some extent similar to those applied usually in the industry when the suspension is subjected to the analogous treatment in the electric arc-furnace. Some suggestions are formulated how to improve the industrial direct-to-blister process.
Formation of Al-alloyed Layer on Magnesium with Use of Casting Techniques
Authors: Mola R. , Bucki T. , Dziadoń A.
Published: January 2016

Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al, Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670°C and 310°; variant 2 – 680°C and 310°C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher temperatures of the melt (685°C) and the mould (325°C) resulted in deep penetration of aluminium into the magnesium substrate. Areas enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from 187-256 HV0.1.
Fractional Schrödinger–Poisson Systems with a General Subcritical or Critical Nonlinearity
Authors: Zhang Jianjun , do Ó João Marcos , Squassina Marco
Published: January 2016

We consider a fractional Schrödinger–Poisson system with a general nonlinearity in the subcritical and critical case. The Ambrosetti–Rabinowitz condition is not required. By using a perturbation approach, we prove the existence of positive solutions. Moreover, we study the asymptotics of solutions for a vanishing parameter.
Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
Authors: Wajs Jan , Mikielewicz Dariusz , Fornalik-Wajs Elżbieta , Bajor Michał
Published: January 2016

A tendency to increase the importance of so-called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative production of heat and electricity. For such systems the crucial points are connected with the heat exchangers, which should be small in size but be able to transfer high heat fluxes. In presented paper the prototype microjet heat exchanger dedicated for heat recovery systems is introduced. Its novel construction is described together with the systematical experimental analysis of heat transfer and flow characteristics. Reported results showed high values of the overall heat transfer coefficient and slight increase in the pressure drop. The results of microjet heat exchanger were compared with the results of commercially available compact plate heat exchanger.
Dependence of the boiler flue gas losses on humidity of wood biomass
Authors: Dzurenda Ladislav , Banski Adrián
Published: January 2016

The paper analyzes the influence of humidity of combusted wood biomass on the flue gas losses. A mathematical relation between flue gas losses of the boiler on wood biomass humidity is presented as well as temperature of flue gas emitted from the boiler into the atmosphere. The limits of model application for the humidity of wood biomass falls into the interval 10–60% whereas the range of temperatures of flue gases emitted from the boiler to the atmosphere is 120–200 °C. The influence of the humidity of wood biomass has an adverse effect on increasing the extent of the boiler flue gas losses and thus inefficiency of the heat production. The increase of the wood biomass humidity from the value of 10% to 60% with the outlet temperature of flue gases from the boiler 120 °C causes an increase in flue gas loss of the boiler from the value 8.37% to 12.43%, similarly the increase of flue gas loss by 200 °C from 15.19% to 22.55%, or the increase of the flue gas loss by 7.36%.
Practical Use of the Eye Camera in Pedagogical Research (Processing of Selected Data Using the Eye Tracking Method)
Authors: Škrabánková Jana
Published: January 2016

The paper deals with author’s pilot experiments using the eye tracking method for the primary school children examination. This method enables to gain a large amount of research data based on the tested people’s eye movements monitoring. In the paper, there are processed chosen research data of four gifted students’ examination in the context of their mathematical and logical intelligence.
Visual Observations as Exercises in Physics
Authors: Drga Jozef , Bulko Martin , Petrík Karol , Csatáryová Mária , Šimkovič Stanislav
Published: January 2016

Visual meteor observations are a fun and interesting approach to astronomy and to scientific research in general. It can be used for laboratory or practical exercises in physics at high schools and universities. The students can personally collect and analyze the acquired data. The output consists of Zenithal Hourly Rate (ZHR) values, spatial density and population index. In this paper, the so called counting method is described as it is the most suitable method for beginners. As a practical example, the ZHR curve of the Lyrid meteor shower was evaluated and the maximum and the duration of the shower were calculated.
Simple scalable nucleotic FPGA based short read aligner for exhaustive search of substitution errors
Authors: Fehér Péter , Fülöp Ágnes , Debreczeni Gergely , Nagy-Egri Máté , Vesztergombi György
Published: January 2016

With the advent of the new and continuously improving technologies, in a couple of years DNA sequencing can be as commonplace as a simple blood test. The growth of sequencing efficiency has a larger exponent than the Moore’s law of standard processors, hence alignment and further processing of sequenced data is the bottleneck. The usage of FPGA (Field Programmable Gate Arrays) technology may provide an efficient alternative. We propose a simple algorithm for DNA sequence alignment, which can be realized efficiently by nucleotic principal agents of Non.Neumann nature. The prototype FPGA implementation runs on a small Terasic DE1-SoC demo board with a Cyclone V chip. We present test results and furthermore analyse the theoretical scalability of this system, showing that the execution time is independent of the length of reference genome sequences. A special advantage of this parallel algorithm is that it performs exhaustive search producing all match variants up to a predetermined number of point (mutation) errors.
Sapiness–sentiment analyser
Authors: Jánosi-Rancz Katalin Tünde , Kátai Zoltán , Bogosi Roland
Published: January 2016

In our ever-evolving world, the importance of social networks is bigger now than ever. The purpose of this paper is to develop a sentiment analyzer for the Hungarian language, which we can then use to analyze any text and conduct further experiments. One such experiment is an application which can interface with social networks, and run sentiment analysis on the logged-in users friends’ posts and comments, while the other experiment is the use of sentiment analysis in order to visualize the evolution of relationships between characters in a text.
Embryological features, pollen and seed viability of Arnica montana (Asteraceae) – a threatened endemic species in Europe
Authors: Yankova-Tsvetkova Elina , Yurukova-Grancharova Petka , Baldjiev Georgi , Vitkova Antonina
Published: January 2016

The embryological features, mode of reproduction and reproductive capacity (pollen and seed viability) on two naturalized populations of Arnica montana in Bulgaria were studied. The embryological study shows that A. montana is a facultative apomictic species in which sexual reproduction predominates. In this species, it was established that there is a comparatively high viability of the mature pollen and embryos, which enables the successful realization of its reproductive capacity. The results of the study on A. montana reveal that both sexual and asexual vegetative reproduction with rhizomes undoubtedly play more important roles than the apomixis (namely diplospory) for support and preservation of the populations.
How Far is Environmental Engineering from Biomedical Engineering?
Authors: Zarzycki Roman , Nawrotek Katarzyna
Published: January 2016

The development of science, which has been observed in recent years, shows that engineering knowledge and activity are becoming more and more interdisciplinary. Up to the late 80-ties of the previous century, the experience and interest of engineers covered mainly hard sciences that directly followed their education. After this period, the engineering knowledge and solutions proposed in one discipline started to be applied successfully in other domains. This tendency can be seen especially in Biomedical Engineering, which development is based on achievements made in the rest of hard sciences, even if they seem to be as distant as Environmental Engineering.
Q-Methodology Study of Students Behaviour During Project-Based Learning
Authors: Németh Gabriella , Prokša Miroslav
Published: January 2016

The contribution describes the circumstances of the implementation of a chemistry project with the main theme “Chemical show - Harry Potter”. Project-based learning belongs between the complex teaching methods, where the desired effect can be influenced by many factors, eg student’s attitude, student’s overall opinion and feelings about the method. The motivation of the researchers was to understand and evaluate the factors present in the realised project. The analysed factors and behavioural schemes can provide a good starting point for the teachers at planning their projects. With the aim to understand the students’ reaction the researchers used Q-methodology to identify the different behavioural groups of participating students based on their real opinion. In the presented research the researchers analyse the response of totally 26 students. As a result totally 6 behavioural examples are presented that teachers can meet during implementation of project based learning. The presented categorization collaborates with other formerly publicised types of student’s behaviour, eg students of “pleasant surprises” and “disappointing surprises”. However, other additional types of behavioural types emerged eg students orienting and concentrating on the theoretical knowledge, students with very strong need for leading and students with the need of several assessment systems. The presented results can provide a wider view for the teachers in preparing and forecasting the flow of their projects and can help them to prepare the project.
Modelling of Emissions from Large Biogas Plants
Authors: Kříž Jan , Hyšplerová Lidmila , Smolík Marek , Eminger Stanislav , Vargová Agáta , Keder Josef , Srněnský Radomír , Dołhańczuk-Śródka Agnieszka , Ziembik Zbigniew , Wacławek Maria
Published: January 2016

The main objective of the “Guidelines for the development of agricultural biogas plants in Poland within 2010-2020”, is a construction of biogas plants processing agricultural biomass resources with suitable conditions in each municipality. In the Czech Republic produces about 6.5% of energy from renewable sources. Biogas plants give - contrary to solar and wind electricity stations - the stable performance throughout the whole year. Biomass should be a key source for achieving the Czech EU commitment to produce 13% of energy from renewable sources in 2020. The experience, where 317 Agricultural biogas plants are currently in operation, has shown that there are considerable problems with a proper location of newly designed agricultural biogas plants in the landscape. The Czech-Polish border area is mainly flat wooded recreation region. For these reasons, the Gaussian model SYMOS’97 (version 2013), adapted for odour dispersion modelling from large agricultural sources is supposed to be suitable for this area. It is appropriate for training of students. For these reasons, students from the University of Hradec Kralove and the University of Opole in the frame of their academic exchange and professional internships are acquainted with the technological principles of biogas plants and in environmental mathematical and statistical modelling of the spread of emissions from large industrial and agricultural sources. In this article we present methods for education on these professional areas.
Foliar Nitrogen Management for Improving Growth and Yield of Dryland Wheat
Authors:   Amanullah, Alam I. ,   Hidayatullah, Khan I. , Kumar M. , Shah A.
Published: January 2016

Foliar nitrogen (N) application is considered an important factor affecting phenology, growth, yield, and yield components of dryland wheat (Triticum aestivum L.). A field experiment was conducted to study effects of foliar N on dryland wheat (cv. Prisabk-2004) at the Agronomy Research Farm, The University of Agriculture Peshawar, Pakistan, during winter 2010-2011. The experiment was laid out in randomized complete block design using four replications. A plot size of 3 m by 4 m, having 8 rows, 4 m long and 30 cm apart was used. A total of 80 kg N ha−1 in the form of urea was applied. Out of 80 kg N ha−1, 70 kg N ha−1 was applied to the soil at sowing time, and the remaining 10 kg N ha−1 was applied in the form of foliar spray (2% N). The required foliar N was applied in various combinations (splits) at different growth stages viz. 30, 60, 90 and 120 days after emergence (DAE). Phenological development (days to anthesis and physiological maturity) was delayed, yield components and yield increased significantly (p ≤ 0.05) with foliar N over control (water spray without N). Wheat grain yield increased to the highest level (4427 kg ha−1) when 100 % foliar N was applied (no split) at 90 DAE, followed by 4050 kg ha−1 at 120 DAE, while the control (no foliar N) resulted in the lowest grain yield (2573 kg ha−1). We concluded from this study that 2 % foliar N application in a single split either at 90 or 120 DAE could improve wheat productivity under dryland condition.
Effect of Different Priming Methods on Germination and Seedling Establishment of Two Medicinal Plants under Salt Stress Conditions
Authors: Younesi O. , Moradi A.
Published: January 2016

Priming is one of the seed enhancement methods that might be resulted in increasing seed performance (germination and emergence) under stress conditions, such as salinity. Salinity is a major environmental stress which adversely affects germination and seedling establishment in a wide variety of crops. The experiment was arranged as a factorial in completely randomized design (CRD) at Seed Research Laboratory of College of Agriculture, University of Tehran, Iran. The objective of this research was to evaluate the effect of different priming methods on seed germination of two medicinal plants including lemon balm (Melissa officinalis L.) and cumin (Cuminum cyminum L.) under salinity stress. Treatments were combinations of two levels of salinity stress (0 and 10 dsm−1) and five levels of priming (control = non-priming), GA3, manitol, NaCl and distilled water) with three replications. Seeds of lemon balm and cumin were primed for 24 h at 25°C. Results revealed that different growth traits (including germination percentage, germination rate, seedling dry weight, plumule and radical length) significantly (p=0.05) decreased with applying salinity. However, priming of seeds with different materials particularly GA3 was useful for alleviating salt stress effects and improving germination and seedling establishment under salt stress. Under salinity condition, primed seeds possessed more germination and emergence than control. The result of this experiment is consistent with the hypothesis that under salinity stress, priming can prepare a suitable metabolic reaction in seeds and can improve seed germination performance and seedling establishment.
Results Obtained in Breeding of Bitter Cherry Assortment at Fruit Growing Research Station Iaşi - Romania
Authors: Iurea Elena , Sîrbu Sorina , Corneanu G.
Published: January 2016

The paper proposes the improvement of the current bitter cherry assortment with new creations made at Iaşi, adapted to the specific conditions from the NE area of Romania. For the improvement of the bitter cherry assortment with new, productive, disease resistant cultivars with fruits of good quality, resistant to cracking with different maturation stages, in 1981 at Fruit Growing Research Station (F.G.R.S.) Iaşi - Romania has begun an action of selection and promoting of some valuable genotypes of bitter cherry (existent in the spontaneous flora or in plantations from the Iaşi county), which were being planted with cultivars and other genotypes from all around the country. Following the positive and gradual selection there were selected three biotypes of bitter cherry from which two of them have been approved as new cultivars in 1994, with the names „Amar Maxut”, respectively, „Amar Galata” and the biotype „Amar R5.P10” has been registered in 2013 at the State Institute for Variety Testing and Registration Bucharest to be approved as a new cultivar. All three bitter cherry genotypes correspond to the objectives of the main assortment breeding. They have a high productivity because the natural fertility index registered values between 36.5-63.7%, the trees have a reduced vigour, they present a good resistance to frost (1-9% affected buds) and to diseases (values of I% anthracnose, 1.1-2.8%). The fruits are high quality and the maturation stages are at the extremities of the cherries maturation season.
Peculiarities of Human Resources Management in Sustainable and Ecological Farms
Authors: Brezuleanu St. , Brezuleanu Carmen Olguţa , Dinu T. Ad. , Stoian Elena
Published: January 2016

Human resources management in agricultural farms is of particular importance in the context of the particularities of labor in agriculture, which is different from other economic sectors. Since labor is the most important production factor of any economic activity, labor productivity is the most used in the evaluation of economic efficiency. Accelerating the productivity growth is related to understanding content and its meaning, major factors of influence and way of exploitation. To emphasize human resource management and to illustrate the way of calculation of labor productivity, the study was conducted in an ecological farm with a vegetable profile of Iaşi County, Romania. The labor productivity has been used in the evaluation of economic efficiency, for three major crops: wheat, maize and potatoes. We used three indicators: average efficiency factor of production land use, WPm; the average productivity of labor in physical units, WLm; labor productivity, WH; labor productivity in monetary value, WV. To increase the labor productivity and efficiency of human resources there were organised training courses and programs both of managers and directly involved productive staff, but also there were introduced new production technologies that lead to ease and make efficient the staff work.
Trace Elements in Mediterranean Mussels Mytilus galloprovincialis from the South African West Coast
Authors: Bezuidenhout Jacques , Dames Nicole , Botha Alfred , Frontasyeva Marina V. , Goryainova Zoya I. , Pavlov Dmitry
Published: January 2016

Invasive bivalve molluscs, Mediterranean mussels (Mytilus galloprovincialis) were used as sentinel biomonitors of pollution by inorganic contaminants in Saldanha Bay and the Langebaan Lagoon area of South Africa. Two complementary analytical techniques, ICP-MS and NAA, allowed for determination of concentrations of 31 major and trace elements including heavy metals and arsenic in the soft tissues of the mussels. Distinct seasonal patterns were found in the dynamics of these concentrations, with the mussels accumulating much more trace elements in winter than in the summer. In general, the mussels that grew naturally also demonstrated higher concentrations of As, Cd, Fe, Hg and Zn than those that were farmed. Fe showed the highest levels with a maximum concentration of 444 mg/kg followed by Zn with a maximum of 228 mg/kg. The concentrations of Mn and Pb were significantly higher in the Port of Saldanha close to the jetty where ores containing these metals are loaded in comparison with the other sampling sites. It was concluded that bivalve molluscs present themselves as effective biomonitors when assessing marine aquatic pollution by inorganic contaminants in the Saldanha Bay region.
Use of Various Zero Valent Irons for Degradation of Chlorinated Ethenes and Ethanes
Authors: Wacławek Stanisław , Nosek Jaroslav , Cádrová Lucie , Antoš Vojtech , Černík Miroslav
Published: January 2016

Amongst all of the reducing agents that can be used in environmental remediation, zero valent iron (ZVI) is one of the most common due to its environmental acceptance, high reaction rate, good availability, and long-term stability. Moreover, ZVI mobility, stability and reactivity can be enhanced by the application of a DC electric current, ie electrokinetics (EK). In the study, six various slurries containing different ZVI were tested for their efficacy for chlorinated ethenes and ethanes degradation. Chlorinated compound concentrations, pH, oxidation-reduction potential (ORP) and conductivity were determined during the long-term kinetic test. Kinetic rate constants calculated for the degradation of three chlorinated ethenes (PCE, TCE and cis-DCE) concluded that EK brings substantial contribution to chlorinated compounds degradation. Nano-scale zero valent iron STAR had the highest reaction rates compare to the other ZVI tested. The performed study could serve as a preliminary assessment of various available ZVI before in-situ application.
Environmental Impact of Exploration from Unconventional Gas Deposits in Poland
Authors: Macuda Jan , Konieczyńska Monika
Published: January 2016

Shale formations have been recently treated only as source rocks and sealing packages mainly of conventional deposits. At present shales, which have a considerable concentration of highly mature organic matter appearing in complexes of over 30 m thick are used as unconventional sources for natural gas production with the use of advanced drilling technologies. Natural gas production in such rock formations necessitates performing a horizontal section in the borehole and a big number of hydraulic fracturing jobs. The unconventional shale gas deposits have been prospected also in Poland for a couple of years. Exploration works mainly concentrate on a vast area passing from Pomerania through Mazowsze to the Lublin region in Poland. The analysis of the geologic analyses reveals that the most perspective are shales in the Lower Paleozoic at a depth of 2500 m in the eastern part to about 4000 m in the western part of the area. The paper is focused on the quantitative and qualitative evaluation of environmental impact of natural gas exploration works from unconventional deposits. Special attention was paid to the hydraulic fracturing jobs in shales, which create particular hazard for water and soil environment. These hazards already appear at the stage of preliminary works, when big quantities of chemicals and water for frac jobs are stored in the rig area, and then, during realization of works, when the spent hydraulic fracturing fluid may penetrate the water-bearing horizons in the caprock. The composition of fracturing fluid used in Gapowo B-1A well are given along with the results of chemical analyses of a few parts of spent fracturing fluid samples pumped out from the borehole. The fluid turned out to be high in salt (high specific electrolyte conductance (SEC) and total dissolved substances (TDS) and a high toxicity for most of the living organisms). For this reason the spent fracturing fluid should not enter the environment without control.
Attitudinal Factors Affecting Wiki Group Collaboration for English Writing
Authors: Chen Chwen Jen , Chuah Kee Man , Tho Jimmy , Teh Chee Siong
Published: January 2016

Wikis, being one of the popular Web 2.0 tools, have impacted students’ engagement and performance particularly in the aspects of second and foreign language learning. While an increasing number of studies have focused on the effectiveness of wiki in improving students’ writing skills, this study was conducted to examine the attitudinal factors that influence English as a Second Language (ESL) students’ group collaboration in using wikis for a writing task that was divided into three phases: pre-writing, individual-construction, joint-constructions. Data collected from these students after completing this task was analyzed based on three attitudinal aspects: motivation, perceived usefulness, and perceived ease of use. The findings reveal high mean scores for all aspects. Further multiple regression analysis reveals that motivation is the most important factor associated with group collaboration, indicating the need to boost students’ motivation to encourage effective collaboration in completing wiki writing tasks.
Emotions Experienced by Learners and their Development through Communication with the Tutor-Counsellor
Authors: Kalogiannakis Michail , Touvlatzis Sotiris
Published: January 2016

The effective communication between the learners and the tutor-counsellor has been proved to significantly promote the positive emotions, reduce the negative ones and reinforce the learners’ participation in a distance learning program. The main purpose of our research is to investigate the emotions experienced by the learners of the Hellenic Open University (HOU) and how these emotions may vary through interaction with the tutor-counsellor. In order to carry out the research, a combination of quantitative and qualitative methods was implemented. Data collection was performed via an anonymous questionnaire and semi-structured interviews. The sample of the research consisted of undergraduate and post-graduate students of the HOU. Our findings confirm the dominant place occupied by emotions in the learning process, a place that has been until recently entirely attributed to reason, while highlighting the communicative and supportive role to be taken by the tutor-counsellor in distance learning programs.
A Learning Analytics Methodology for Detecting Sentiment in Student Fora: A Case Study in Distance Education
Authors: Kagklis Vasileios , Karatrantou Anthi , Tantoula Maria , Panagiotakopoulos Chris T. , Verykios Vassilios S.
Published: January 2016

Online fora have become not only one of the most popular communication tools in e-learning environments, but also one of the key factors of the learning process, especially in distance learning, as they can provide to the students involved, motivation for collaboration in order to achieve a common goal. The purpose of this study is to analyse data related to the participation of postgraduate students in the online forum of their course at the Hellenic Open University. The content of the messages posted is analysed by using text mining techniques, while the network through which the students interact is processed through social network analysis techniques. Furthermore, sentiment analysis and opinion mining is applied on the same dataset. Our aim is to study students’ attitude towards the course and its features, as well as to model their sentiment behaviour over time, and finally to detect if and how this affected their overall performance. The combined knowledge attained from the aforementioned techniques can provide tutors with practical and valuable information for the structure and the content of the students’ exchanged messages, the patterns of interaction among them, the trend of sentiment polarity during the course, so as to improve the educational process.
Massive Open Online Courses and Economic Sustainability
Authors: Liyanagunawardena Tharindu R. , Lundqvist Karsten O. , Williams Shirley A.
Published: January 2016

Millions of users around the world have registered on Massive Open Online Courses (MOOCs) offered by hundreds of universities (and other organizations) worldwide. Creating and offering these courses costs thousands of pounds. However, at present, revenue generated by MOOCs is not sufficient to offset these costs. The sustainability of MOOCs is a pressing concern as they incur not only upfront creation costs but also maintenance costs to keep content relevant, as well as on-going facilitation support costs while a course is running and re-running. At present, charging a fee for certification seems to be a popular business model adopted by leading platform providers.

In this position paper, the authors explore possible business models for courses, along with their advantages and disadvantages, by conducting a literature study and applying personal insights gained from attending various MOOC discussion fora. Some business models discussed here are: the Freemium model, sponsorships, initiatives and grants, donations, merchandise, the sale of supplementary material, selective advertising, data-sharing, follow-on events, and revenue from referrals. This paper looks at the sustainability of MOOCS as opposed to the sustainability of MOOC platforms, while observing the tight link between them.
Diagram Rules as a Challenge in Complex Regulation
Authors: Pečarič Mirko
Published: January 2016

States are trying to achieve the best results in the increasingly changing conditions. A creation of sophisticated systems that would be able to display complex situations with the simple initial rules is a challenge for the present and future era. The effectiveness of a legal norm does not depend on its content, but on its form. This paper tries to give an explanation about the effects of legal norms, which emerge through their repetitions and fused with new information without sacrificing legality and regardless of the human cognitive shortcuts. With this goal the paper is based on the atypical physical and biological properties of law that offer a new perspective on the legal norms. On this basis the change of the traditional form of legal norm is presented with the diagram and/or algorithm that could, based on the computerised operations, include more statistic or natural sampling propositions.
Effect of Aggregate Gradation on the Stiffness of Asphalt Mixtures
Authors: Al-Mosawe Hasan , Thom Nick , Airey Gordon , Al-Bayati Amjad
Published: January 2016

Aggregate gradation plays an important role in the behaviour of asphalt mixtures. Packing of aggregate is a very important factor that will be affected by changing the aggregate gradation. Many researchers have investigated different ways of describing packing both theoretically and practically. Bailey ratios have recently been used to understand the volumetric properties of mixtures. In this paper, the Bailey ratios have been used, and two further ratios have also been introduced to allow the asphalt mixture gradation to be fully understood. Thirteen different aggregate gradations have been chosen within the 14 mm asphalt concrete specification to investigate the effect of particle size distribution on the stiffness of the mixture. It was found that variation in aggregate gradation has a significant effect on asphalt stiffness, even within specification limits, and a reasonable correlation between the set of ratios investigated and the Indirect Tensile Stiffness.
Variability in Pavement Design
Authors: Valle Paola Dalla , Thom Nick
Published: January 2016

This paper presents the results of a review on variability of key pavement design input variables (asphalt modulus and thickness, subgrade modulus) and assesses effects on pavement performance (fatigue and deformation life). Variability is described by statistical terms such as mean and standard deviation and by its probability density distribution.

The subject of reliability in pavement design has pushed many highway organisations around the world to review their design methodologies, mainly empirical, to move towards mechanistic-empirical analysis and design which provide the tools for the designer to evaluate the effect of variations in materials on pavement performance. This research has reinforced this need for understanding how the variability of design parameters affects the pavement performance.

This study has only considered flexible pavements. The sites considered for the analysis, all in the UK (including Northern Ireland), were mainly motorways or major trunk roads. Pavement survey data analysed were for Lane 1, the most heavily trafficked lane. Sections 1km long were considered wherever possible.

Statistical characterisation of the variation of layer thickness, asphalt stiffness and subgrade stiffness is addressed. A sensitivity analysis is then carried out to assess which parameter(s) have the greater influence on the pavement life.

The research shows that, combining the effect of all the parameters considered, the maximum range of 15th and 85th percentiles (as percentages of the mean) was found to be 64% to 558% for the fatigue life and 94% to 808% for the deformation life.
The Big Data Mining Approach for Finding top rated URL
Authors: Shyam Mohan J.S. , Shanmugapriya P. , Vinay Pawan Kumar Bhamidipati
Published: January 2016

Finding out the widely used URL’s from online shopping sites for any particular category is a difficult task as there are many heterogeneous and multi-dimensional data set which depends on various factors. Traditional data mining methods are limited to homogenous data source, so they fail to sufficiently consider the characteristics of heterogeneous data. This paper presents a consistent Big Data mining search which performs analytics on text data to find the top rated URL’s. Though many heuristic search methods are available, our proposed method solves the problem of searching compared with traditional methods in data mining. The sample results are obtained in optimal time and are compared with other methods which is effective and efficient.
Design and Analysis of EDF Scheduling Algorithm for a Chosen Network Traffic Problem: Implementation and Simulation Analysis
Authors: Ighodaro Jude
Published: January 2016

Workstations, CPU etc are in a period of transition, moving from a relatively slow network links and data oriented services to a high set fibre optic services and more diverse services. As such many of the hard and soft real time will not only demand high bandwidth but also a predictable and guarantee Quality of Service (QoS) along side, which is not offered in a best effort network (BE). The provision and terms of (QoS) to real-time applications is a key issue in promising broadband packet switched networks and network of other sorts. Applications such as voice and video typically require QoS guarantees in terms of end-to-end data transfer delays. Supporting the diverse and of course, heterogeneous delay requirements of applications with widely varying characteristics requires packet scheduling schemes more sophisticated than First-In-First-Out (FIFO) at each switch in the network(2) are one of most accepted examples of such scheduling schemes. This points to the convincing need for a QoS, which apportion a high network utilization to be realized. In this paper, we focus on the EDF scheduling scheme, since it is known to provide the optimal delay performance (2), in the deterministic environment, and can for this reason be expected to perform well in the real time setting as well. The large amount of bandwidth as promised by the future network also offer the integration of real time applications, hard or soft.
Role of Regulatory Bodies in the Banking and Energy Sectors
Authors: Jakšić Miomir
Published: January 2016

The article discusses the status and role of regulatory bodies and the aftermaths of their independence and accountability to the public and the parliament. The author analyses different legal statuses of regulatory bodies in Montenegro and Serbia in the central banking and energy sectors and concludes that it is necessary that national constitutions, as the highest legal acts in each state, prescribe in a separate article that “Regulatory bodies are independent and accountable to Parliament”.

Relevant separate legal acts should closely define the procedures for establishing, enforcing, and sanctioning of possible breaching of: 1) independence of regulatory bodies, 2) accountability of regulatory bodies to the parliament, and 3) transparency of their activities.
Integration of Government Bond Market in the Euro Area and Monetary Policy
Authors: Lukić Velimir
Published: January 2016

This paper combines analysis of evolution in euro area government bond market integration and interference of European Central Bank with functioning of respective market recently. Since the introduction of euro, government bond yields converged in the euro area, bonds of different countries have become close substitutes in the perception of investors, and overall integration of the market was rather high. At the end of 2008, dramatic shift occurred and ever since disintegrative forces were set in motion. The paper presents the following measures of integration of the government bond markets: yield spreads, dispersion in yield spreads and beta coefficient. All three measures suggest unprecedented market disintegration as of 2010. The paper highlighted relevance of sovereign bond market for the smooth functioning of the monetary policy transmission mechanism in a monetary union context. Three ECB’s programmes aimed at sovereign debt crisis resolution were analysed in details. They proved successful in lowering peripheral countries’ yields and spreads, and calming the markets. If one takes central bank function of the lender of last resort for banks, then these programmes may be viewed as the “buyer of last resort” device for government bonds. Although warranted by exceptional circumstances and need for swift response, a due caution should be paid to these programmes since they pose certain challenges for conduct of monetary policy and might even have unintended consequences.
Aggregate Demand–Inflation Adjustment Model Applied to Southeast European Economies
Authors: Apostolov Mico , Josevski Dusko
Published: January 2016

Applying IS-MP-IA model and the Taylor rule to selected Southeast European economies (Albania, Bosnia and Herzegovina, Macedonia and Serbia) we find that the change of effective exchange rate positively affects output, while the change of the world interest rate negatively affects output or it does not affect the output at all, and additional world output would help to increase output of the selected economies.

A lower ratio of government consumption spending to GDP would also increase the output of the selected economies. Hence, fiscal prudence is needed, and the conventional approach of real depreciation to stimulate exports and raise real output does not apply to the selected Southeast Europe economies.

When private household consumption is employed in the model, the coefficient on government spending to nominal GDP is insignificant implying that Ricardian equivalence does hold for the selected countries.