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Kozani, Greece

Τhe University of Western Macedonia is a multi-campus university in Northwestern Greece. It was established on 2004 by four departments that had previously formed part of the Aristotle University of Thessaloniki. As of May 2013, it consists of the following faculties and departments: Faculty of Educational science:Department of Elementary Education Department of Nursery Education Faculty of Engineering:Department of Mechanical Engineering Department of Engineering Informatics and Telecommunications Faculty of Arts: Department of Applied and Visual Arts Wikipedia.

Koroneos C.J.,National Technical University of Athens | Nanaki E.A.,University of Western Macedonia
Journal of Cleaner Production | Year: 2012

Innovative strategies are needed to deal with the waste we produce today to prevent it from causing problems for future generations. As waste management issues gain public awareness, concern has risen about the appropriateness of various disposal methods. The objective of this work is the environmental assessment of different municipal solid waste treatment strategies for the city of Thessaloniki, within the methodological frameworks of Life Cycle Assessment (LCA) and the Integrated Solid Waste Management strategy, taking into account social, environmental and economic effects. The waste management methods in this study include: landfill of all waste fractions, recycling of paper, and anaerobic digestion of food waste in a biological treatment plant. The waste fractions considered are the total amount of food, paper and plastic waste produced in Thessaloniki during the period of one year. Environmental impacts are decreased when the solid waste management methods include some kind of recovery from waste. The results of this work indicate that paper recycling and anaerobic digestion of food waste is preferable compared to landfilling. It is also shown that landfilling of food waste utilizing the biocells method is more attractive than anaerobic digestion in a separate plant; nevertheless, energy recovery is about 45% lower. © 2011 Elsevier Ltd. All rights reserved.

Vekiri I.,University of Western Macedonia
Computers and Education | Year: 2010

The purpose of the study was to explore possible links between student socioeconomic status (SES), beliefs about information and communication technologies (ICTs), and out-of-school learning resources. Grades 5 and 6 students (N = 345) who were enrolled in one private and six public elementary schools in Greece, located in areas with different demographic characteristics, responded to a questionnaire addressing their ICT self-efficacy and value beliefs, out-of-school ICT access and activities, perceived parental support and regulation of home ICT activities, and access to sources of technological support beyond the family. Findings showed that students from all SES family backgrounds tended to have positive views about the value of ICTs, but students from low-SES families expressed lower confidence in their ICT skills. Parents from all SES backgrounds appeared to view equally favorably their children's engagement with ICTs, and perceived parental support correlated highly with students' ICT value beliefs. However, students from low-SES families appeared to have fewer opportunities to develop ICT competencies, which may explain why they expressed less positive self-efficacy beliefs. Findings stress the need for school ICT integration efforts to take into account student differences in prior experiences and to be coordinated with students' home computer use. © 2009 Elsevier Ltd. All rights reserved.

Vekiri I.,University of Western Macedonia
Computers and Education | Year: 2010

This exploratory study took place in the context of middle school information science in Greece, to examine possible relations between boys' and girls': value and efficacy beliefs about computers and information science; perceived parental support; perceived teacher expectations; and perceptions of the nature of information science instruction. The participants of the study were 301 (135 male and 166 female) students who responded to a self-report questionnaire. Regression analysis showed that perceived teacher expectations were positively associated with students' ability beliefs, perceptions of learning activities as creative and personally meaningful was a significant predictor of students' interest in computing, and perceived parental support was related to both value and efficacy beliefs. Unlike previous research, the findings of this study did not support the conclusion that boys have more positive ICT self-efficacy and value beliefs than girls. They indicated however, that boys' and girls' beliefs are differentially affected by parents, teachers, and school IS instruction. © 2009 Elsevier Ltd. All rights reserved.

Konstantinidis E.,University of Western Macedonia
Journal of Fluids and Structures | Year: 2013

This communication brings forward the concept of an effective drag for circular cylinders undergoing controlled or self-excited oscillation transverse to a free stream. A relationship betweenthe effective drag and the apparent drag customarily measured by force transducers, is derived on the basis of the average rate of energy dissipation in the fluid. The effective drag is employed to gain insight into the fluid dynamics of vortex-induced vibrations using available data from the published literature. It is shown that the effective drag varies almost continuously as a functionof the true reduced velocity except for a sudden decrease near conditions of maximum amplitude. The variation displays simila-rities but also important differences among independent experiments, which highlight the importance of various influencing parameters whose effect on the free response is currently not well understood. Some evidence is found that self-excited oscillations occur at points in the frequency-amplitude space where the effective drag is comparatively low avoiding the region where energy transfer from the fluid to the structure is most efficient. A total energy balance is employed to reveal the effect of mechanical damping on the free response which indicates that the amplitude scales with the inverse of the square root of damping in conformity with experimental data. The dimensionless damping parameters proposed by Vandiver are examined in light of thepresent analysis, and alternative empirical formulas are suggested for organizing the free vibration response. © 2013 Elsevier Ltd.

Nenes G.,University of Western Macedonia
International Journal of Production Economics | Year: 2011

This paper proposes a unified approach for the development of economically designed Variable-parameter (Vp) X̄-Shewhart, X̄-CUSUM and X̄-EWMA control chart models, for monitoring the process mean in infinite-horizon production runs. The use of the models allows at each sampling epoch the determination of the scheme parameters that minimize the quality-related expected cost of the procedure based on the actual value of the chart statistic. The models are simple and fast as they avoid the inaccuracies and inefficiencies associated with the interim computation of statistical performance measures such as ANSS, ANOS, etc. The effectiveness of the schemes is evaluated by comparing their optimal expected costs against each other and against the costs of Fixed-parameter (Fp) charts. These comparisons demonstrate the superiority of Vp X̄-CUSUM and Vp X̄-EWMA charts over Vp X̄-Shewhart charts which in turn are economically superior to Fp control charts. © 2010 Elsevier B.V. All rights reserved.

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