Showing papers by "Technological Educational Institute of Western Macedonia published in 2018"

The potential of glycerol and phenol towards H2 production using steam reforming reaction: A review

Abstract: Hydrogen production via the steam reforming of glycerol, the main by-product of biodiesel production, and the pyrolysis/gasification route of biomass are two processes that have drawn considerable attention by the scientific community due to their potential in reducing our dependence on fossil based sources and in mitigating the effects of greenhouses gases on our planet. However, the commercial exploitation of the processes depends on the development of cheap, active and stable catalysts. In the present review, the key literature on the glycerol and phenol steam reforming reactions is presented and discussed. The impact of crucial variables for both the reactions at hand are discussed, such as active metal nature, metal loading, support, reaction temperature, method of preparation, poisoning resistance and coking tolerance. For catalytic systems design purposes the aspect of how the catalyst physicochemical characteristics affect the catalytic performance is addressed. Particular attention is given at the issue of coke resistance of the catalysts due to its detrimental effect for the reactions at hand. Natural materials, such as calcites, dolomites and olivines, utilized for the phenol steam reforming reaction are discussed.

Determinants of Corporate Climate Change Disclosure for European Firms

Abstract: This study identifies the determinants of climate change disclosure under the prism of sustainable development in European context. The selected variables involve environmental performance, ownership structure, and verification of climate change initiatives. Cross-sectional data derived from the Bloomberg terminal of the European 500 index concerning 215 firms in the year 2014 are employed. The novelty of the present study stands on the use of proxies for climate change disclosure by adopting the Climate Performance Leadership Index (CPLI). The results reveal that better environmental performance positively affects the level of climate change disclosure. In addition, governmental ownership and independent verification of environmental data determine climate change disclosure. Thus, climate change disclosure is thought to be an effective managerial tool for shareholders and stakeholders to superintend corporate management limiting information asymmetry level; furthermore, higher environmental performers prefer actual climate change disclosure providing a plausible signal. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment

Mobile shopping consumers' behavior: an exploratory study and review

Abstract: Mobile Technology is creating a range of tremendous opportunities and new revenue streams for businesses across industry sectors through the delivery of chargeable mobile products and services via the deployment of innovative value-added solutions that exploit the commercial benefits of mobility. To keep up with the pace of change, companies increasingly want to understand the behavioral attitude of the modern mobile consumer. The aim of this paper is to find out users' reaction towards different parameters that would influence their intention to utilize their mobile devices in order to purchase products and services online focusing on the current Greek reality. The extant literature focuses on understanding the factors that might affect consumers' behavior intention to adopt m-shopping; these studies are mostly based on behavioral intention theories, such as Technology Acceptance Model, Diffusion of Innovation and Unified Theory of Acceptance and Use of Technology. In this study, new theoretical constructs are combined with existing evidence in order to extend the Technology Acceptance Model as it was initially established by Davis and later further enriched by other researchers. The proposed model includes behavioral intention, mobile skillfulness, enjoyment, anxiety, perceived usefulness, perceived ease of use, trust, relationship drivers, and innovativeness.

Fuzzy Cognitive Map-Based Modeling of Social Acceptance to Overcome Uncertainties in Establishing Waste Biorefinery Facilities

Abstract: Sustainable Waste Biorefinery Facilities (WBFs) represent multifactorial systems that necessitate the organization, cooperation and the acceptance of different social stakeholders. However, these attempts have become targets of environmental, social and legal oppositions despite their obvious economic benefits. The variety of ambivalent and heterogeneous external effects of such projects result in either local support or opposition to the facility, which in turn becomes a critical factor affecting facility location decisions, and subsequent success of a WBF. Research has shown that simple surveys do not sufficiently measure social acceptance of such endeavours, and in most cases, local community factors dominate other external valuable impacts. In the current study, a novel Fuzzy Cognitive Map (FCM) modeling approach is proposed in order to analyze the socio-economic implications and to overcome multiple uncertainties occurring in sustainable WBF development and implementation. The primary investigation relates to the factors that influence the development of organic or chemical treatment of waste by the local communities and the competent authorities. The determination of concepts involved in the FCM modeling depends on a hybrid approach where both experts’ opinion and statistical results from questionnaires distributed to stakeholders participate in the concept circumscription, thus identifying the centrality of each node in the model. Several steady state and dynamic analysis scenarios show the influence of driver concepts to receiver concepts on the social aspect FCM constructed.

Trigonometrical fitting conditions for two derivative Runge-Kutta methods

Abstract: Two derivative Runge-Kutta methods are Runge-Kutta methods for problems of the form y′ = f(y) that include the second derivative y″ = g(y) = f′(y)f(y) and were developed in the work of Chan and Tsai (Numer. Alg. 53, 171–194 2010). Explicit methods were considered and attention was given to the construction of methods that involve one evaluation of f and many evaluations of g per step. In this work, we consider trigonometrically fitted two derivative explicit Runge-Kutta methods of the general case that use several evaluations of f and g per step; trigonometrically fitting conditions for this general case are given. Attention is given to the construction of methods that involve several evaluations of f and one evaluation of g per step. We modify methods with stages up to four, with three f and one g evaluation and with four f and one g, evaluation based on the fourth and fifth order methods presented in Chan and Tsai (Numer. Alg. 53, 171–194 2010). We provide numerical results to demonstrate the efficiency of the new methods using four test problems.

The Effect of Ni Addition onto a Cu-Based Ternary Support on the H₂ Production over Glycerol Steam Reforming Reaction.

Abstract: In the present study, Ni/Ce-Sm-xCu (x = 5, 7, 10 at.%) catalysts were prepared using microwave radiation coupled with sol-gel and followed by wetness impregnation method for the Ni incorporation. Highly dispersed nanocrystallites of CuO and NiO on the Ce-Sm-Cu support were found. Increase of Cu content seems to facilitate the reducibility of the catalyst according to the H₂ temperature-programmed reduction (H₂-TPR). All the catalysts had a variety of weak, medium and strong acid/basic sites that regulate the reaction products. All the catalysts had very high XC3H8O3 for the entire temperature (400–750 °C) range; from ≈84% at 400 °C to ≈94% at 750 °C. Ni/Ce-Sm-10Cu catalyst showed the lowest XC3H8O3-gas implying the Cu content has a detrimental effect on performance, especially between 450–650 °C. In terms of H₂ selectivity (SH2) and H₂ yield (YH2), both appeared to vary in the following order: Ni/Ce-Sm-10Cu ˃ Ni/Ce-Sm-7Cu ˃ Ni/Ce-Sm-5Cu, demonstrating the high impact of Cu content. Following stability tests, all the catalysts accumulated high amounts of carbon, following the order Ni/Ce-Sm-5Cu ˂ Ni/Ce-Sm-7Cu ˂ Ni/Ce-Sm-10Cu (52, 65 and 79 wt.%, respectively) based on the thermogravimetric analysis (TGA) studies. Raman studies showed that the incorporation of Cu in the support matrix controls the extent of carbon graphitization deposited during the reaction at hand.

This time it’s different? Effects of the Eurovision Debate on young citizens and its consequence for EU democracy – evidence from a quasi-experiment in 24 countries

Abstract: For the very first time in EU history, the 2014 EP elections provided citizens with the opportunity to influence the nomination of the Commission President by casting a vote for the main Europarties’ ‘lead candidates’. By subjecting the position of the Commission President to an open political contest, many experts have formulated the expectation that heightened political competition would strengthen the weak electoral connection between EU citizens and EU legislators, which some consider a root cause for the EU’s lack of public support. In particular, this contest was on display in the so-called ‘Eurovision Debate’, a televised debate between the main contenders for the Commission President broadcasted live across Europe. Drawing on a quasi-experimental study conducted in 24 EU countries, we find that debate exposure led to increased cognitive and political involvement and EU support among young citizens. Unfortunately, the debate has only reached a very small audience.

Facebook Content Strategies and Citizens’ Online Engagement: The Case of Greek Local Governments

Abstract: This paper analyzes the communication strategies used by Greek local governments through the utilization of Web 2.0 technologies, specifically Facebook, and the effectiveness of these strategies in relation to citizens’ online engagement. More specifically, it examines Facebook communication strategies and levels of citizens’ engagement. For this purpose, we conducted a content analysis on the active and official Facebook pages of local municipalities in Greece from January 2017 until the end of September 2017. Our results suggest a rise in the percentage of active Facebook pages maintained by local governments in comparison to our 2014 study. Our results also show that local governments in Greece are using Facebook in a predominantly top-down manner to promote events organized by the municipality and to push one-way information to citizens about their services and actions. Local authorities have, however, made significant progress in relation to posts that support transparency and accountability and that enhance or mobilize citizens’ participation. Our evaluation of local government Facebook strategies indicates that marketing the municipality to external public, such as tourists, and providing information about services are effective strategies that drive citizens’ online attitude expression (liking), engagement (commenting), and advocacy behavior (sharing). According to our analysis, local governments in Greece prefer the strategies that we found to be the least engaging. In addition, our study provides interesting details of how specific characteristics and modes of Facebook messages (photos, videos, URLs, hashtags, and mentions) impact on citizens’ engagement. Finally, our results provide valuable insights for social media managers in local government who aim to increase the impact of their municipal Facebook pages.

Economic Viability of Residential PV Systems with Battery Energy Storage Under Different Incentive Schemes

Abstract: The high penetration of distributed renewable energy sources (DRESs), and especially photovoltaics (PVs), in LV distribution grids questions their safe and reliable operation. In this context, battery energy storage (BES) systems can be an effective solution to reduce the intermittency of electricity generated by DRESs and to enhance the resilience of power systems. However, it is unclear how different incentive schemes and regulatory frameworks affect the BES profitability for prosumers, compared with no incentives at all. In this paper, a techno-economic model is developed to investigate the economic viability of BES for residential PVs, operated under different incentive schemes. The input parameters of the model include typical load and generation profiles, electricity prices as well as typical PV and BES costs. Using these data, an optimization procedure based on an exhaustive search is performed and the optimal size of the integrated PV-BES system is derived.

Attack, Interact, and Mobilize: Twitter Communication Strategies of Greek Mayors and their Effects on Users’ Engagement

Abstract: The aim of the present study is to examine the communication strategies used by Greek mayors in Twitter across different periods of an electoral cycle (pre-campaign, campaign, and post-campaign). Moreover, this study tries to delineate the effects of Twitter strategies on users’ engagement and identify the most effective ones. To that end, a content analysis is performed on 32,810 tweets of Greek mayors for a six-year period. Moreover, quantitative metrics such as the number of favorites and retweets are also obtained for each tweet. Results suggest that Greek mayors mainly use Twitter as a press release bulletin board for dissemination of information about the main events taking place in municipality. Moreover, they also use impression management strategies to promote a distinct personal, political and professional image. Results also show that during different periods of an electoral cycle mayors utilize a different mix of Twitter strategies. Furthermore, aggressive (attacking opponents), interactive (direct communication), and mobilization (requesting feedback) strategies are found to be the most effective in enhancing followers’ attitude expression (favorites) and advocacy behavior (retweets). The present study provides valuable practical implications for social media political marketers as well as politicians.

Tourism Consumer Behavior and Alternative Tourism: The Case of Agrotourism in Greece

Abstract: The alternative tourism has a lot of segments according to the specific requirements of the customers, always in order to provide a designed customized leisure. (Ros Derrett, Cultural tourism, Paper presented to Momento, Queensland Merchandise Awards, Brisbane, Qld., 24 July, 2002) More and more travelers are being attracted by these types of tourism, and consequently this creates the development of new potential types of tourists. During the past years there has been a shift from mass tourism into special interest tourism. The reason behind this shift is related with changes on customers’ patterns. According to (Alebaki and Iakovidou in Enometrica 3:15–24, 2010 ; Iakovidou, Vlahou and Partalidou, 2001. Quality directions in rural tourism in Greece, Proceedings of the International Conference on “New Directions In Managing Rural Tourism And Leisure”, Euro Scotland, 5–8/9/2001) tourists seek to focus on turning away from mass tourism since they feel that this mode of tourism does not satisfy their needs for quality driven tourist activities. (Alebaki and Iakovidou in Enometrica 3:15–24, 2010) have also identified other factors which have to do with local communities. On many cases, (Alebaki and Iakovidou in Enometrica 3:15–24, 2010) have examined the case of agro-tourism in Greece where communities need to develop their economies in a way where tourism will not disrupt their natural resources. On many cases tourism has been accused of damaging the natural environment and social cohesion. For example, a visitor can go to an agrotourist unit which produced organic food. He will stay in the hotel found within the premises of the farm while he will have the chance to eat dinners made from organic products. He can also go for hiking, mountain biking, rafting or any other activity near the unit. This means that the consumers who are choosing this type of tourism have their own distinctive behavior. The aim of this paper is to examine this difference. According to (Tsartas, Sustainable tourism, Kritiki, Athens, 2010) this is a special interest group which was developed during last years. It is made from middle age and high or medium income consumers. For many years those consumers constituted the core of mass tourism but now they feel that tourism on overcrowded destinations does not satisfy them anymore. They seek for more quality driven solutions such as spa tourism, sea tourism, etc. On the other hand they will like to visit a sustainable destination, such as an agrotourist unit but they seek to spend their days in a quality driven agrotourist unit and not the average one. They can afford to pay a considerable amount of money for their holidays and if they are satisfy they will not hesitate to suggest the destination on their friends. It is a growing segment and on many countries it has become they segment of special interest tourism. Their key motive is that they can find in those destinations the tranquility and quality that they are looking for. The expected outcome is that consumers who select agrotourist activities also tend to have their own distinctive characteristics, which is vital for the development of Tourism in Greece to examine them.

The drivers of corporate governance disclosure: the case of Nifty 500 Index

Abstract: Based on agency theory, the purpose of this paper is to investigate the determinants on the dissemination level of corporate governance disclosure (CGD).,The sample of the study incorporates listed companies in Nifty 500 Index for the period 2009-2014. The Governance Disclosure Score calculated by Bloomberg is used as a proxy for the dissemination level of corporate governance information. In total, eight explanatory variables are uses, namely, board’s size, number of board meetings, CEO duality, presence of women on the board, company’s size, financial performance, Tobin’s Q ratio and financial leverage.,The results of study suggest a need for improvement in CGDs by Indian companies, as they fail to comply the majority of the proposed disclosure items. Furthermore, it is revealed that the number of board director, the value of company, the financial leverage and the presence of women affect negatively the dissemination level of corporate governance information. While, the size of company is the only determinant that positively affects the extent of CGD.,The results are valuable because they reveal the attributes that determines which companies needs less or extra monitoring by shareholders and investors regarding the applied corporate governance practices. In addition, the study can be valuable to policy makers responsible for the regulation of company’s accountability in relation to corporate governance practices.,The study extents previous studies by incorporating for the first time Bloomberg’s rating approach regarding the dissemination level of CGD in Indian context.

Optimal Siting of BESS in Distribution Networks under High PV Penetration

Abstract: This paper focuses on the optimal siting of Battery Energy Storage Systems (BESS) in a Distribution Network with installed Photovoltaic Generation, in order to minimize the energy losses of the system. The bus voltage limit, as well as the ampacity level of the lines are taken into consideration as constraints, while the technical constraints of the BESSs have also been taken into account. Unified Particle Swarm Optimization is used as the solving optimization technique. Simulations are being carried out on IEEE-33 bus system regarding different scenarios and the results are presented and compared. A significant improvement in energy losses, voltage and line ampacity profile is achieved by the introduction of BESS units in a Distribution Network with high PV Penetration.

Performance and evaluation of a coupled prognostic model TAPM over a mountainous complex terrain industrial area

Abstract: Atmospheric modeling is considered an important tool with several applications such as prediction of air pollution levels, air quality management, and environmental impact assessment studies. Therefore, evaluation studies must be continuously made, in order to improve the accuracy and the approaches of the air quality models. In the present work, an attempt is made to examine the air pollution model (TAPM) efficiency in simulating the surface meteorology, as well as the SO2 concentrations in a mountainous complex terrain industrial area. Three configurations under different circumstances, firstly with default datasets, secondly with data assimilation, and thirdly with updated land use, ran in order to investigate the surface meteorology for a 3-year period (2009–2011) and one configuration applied to predict SO2 concentration levels for the year of 2011.The modeled hourly averaged meteorological and SO2 concentration values were statistically compared with those from five monitoring stations across the domain to evaluate the model’s performance. Statistical measures showed that the surface temperature and relative humidity are predicted well in all three simulations, with index of agreement (IOA) higher than 0.94 and 0.70 correspondingly, in all monitoring sites, while an overprediction of extreme low temperature values is noted, with mountain altitudes to have an important role. However, the results also showed that the model’s performance is related to the configuration regarding the wind. TAPM default dataset predicted better the wind variables in the center of the simulation than in the boundaries, while improvement in the boundary horizontal winds implied the performance of TAPM with updated land use. TAPM assimilation predicted the wind variables fairly good in the whole domain with IOA higher than 0.83 for the wind speed and higher than 0.85 for the horizontal wind components. Finally, the SO2 concentrations were assessed by the model with IOA varied from 0.37 to 0.57, mostly dependent on the grid/monitoring station of the simulated domain. The present study can be used, with relevant adaptations, as a user guideline for future conducting simulations in mountainous complex terrain.

Enhancing storage integration in buildings with photovoltaics (PV-ESTIA project)

Abstract: European Union's energy targets for 2030 include the transformation of the building stock to nearly zero energy buildings (NZEBs). NZEBs are characterized by reduced net-energy demand, since most of their energy needs are met by on-site renewable energy sources, especially photovoltaics (PVs). Consequently, in the following years, a considerable amount of intermittent solar generators will be connected in the electrical grid posing new challenges concerning the secure and reliable grid operation. To effectively address these challenges, the integration of energy storage systems (ESSs) in NZEBs is considered as the most promising solution. Towards this objective, the PV-ESTIA project aims to develop an innovative management scheme for hybrid PV and storage systems in order to promote the use of ESSs in the building environment. In the framework of the project, the proposed management scheme will be tested and validated under real-field conditions at pilot installations placed in the Balkan Mediterranean (Balkan-MED) region. Additionally, the distinct features and functionalities of the proposed scheme will be further evaluated during the project through the development of optimization tools. This paper presents briefly the main activities and the expected outcomes of the PV-ESTIA project, focusing on the conceptual analysis of the foreseen management scheme for hybrid PV and storage systems. Additionally, potential barriers related with the integration of ESSs in buildings at the Balkan-MED region are identified and discussed. Finally, a detailed analysis of the pilot installations which will be developed in the framework of the PV-ESTIA project is presented.

Greenhouse gas emissions from two hydroelectric reservoirs in Mediterranean region

Abstract: Water reservoirs are used for many purposes, such as water supply, irrigation, flood mitigation, and hydroelectric energy generation. Although hydroelectric energy is considered “green,” many studies show that the construction of a reservoir enhances greenhouse gas (GHG) emissions at the transformed area. These emissions, mainly of CO2, CH4, and N2O gases, depend on the age of the reservoir, landscape and soil composition, fauna and flora remnants of the impounded area, climatic conditions, and basin runoffs. Consequently, GHG emissions significantly vary between reservoirs and depending on local specificities. Several studies have investigated GHG emissions from reservoirs around the world, focusing mainly on reservoirs located in cold regions, temperate regions, and tropical regions. Research is lacking for reservoirs in Mediterranean countries, like Greece, and similar regions. This work initially assesses the net GHG emissions of a newly created reservoir (Ilarion est. 2012) in Western Macedonia, Greece. The methodology for net GHG emission calculation was based on the use of literature data concerning pre-impoundment emission factors and local specificities of the reservoir (terrain type, canopy cover), as well as on the 2-year measurement data that were collected using a “static floating chamber.” Furthermore, in this work, the gross GHG emissions of an older, in-line reservoir (Polyfytos est. 1974) were also calculated, based on 2-year measurement data. The results show that the global warming potential (GWP) of the reservoirs is dictated by methane emissions; it minimizes during winter and spring and maximizes during summer and autumn. Hydroelectric energy production at Ilarion Reservoir results in 32 to 97 times less total CO2 equivalent emissions in comparison to fossil fuels, while at Polyfytos Reservoir only 8 to 24 times less (based on gross emissions). It appears that the impact of a reservoir’s morphology on GHG emissions is more significant than that of a reservoir’s age.

A missing data treatment method for photovoltaic installations

Abstract: Due to the high installation rate of Photovoltaics (PV) systems, the challenging task of data processing arises. As the number of intermittent PV systems grows especially in the distribution networks, this task becomes even more important. In many cases, the data present inconsistencies, i.e. missing, incomplete or profoundly wrong values. The present paper proposes a method built on machine learning algorithms for missing data completion. The original incomplete PV generation time series are filled and restored with low error. The proposed method can be easily applied in real installations with high rate of data collection and storage needs.

Cobb-Douglas Production Function: The Case of Poland’s Economy

Abstract: The aim of this paper is to analyze the relationship between international trade and economic and financial development for Poland for the period 1990–2016. For this long run relationship we apply the autoregressive distributed lag—ARDL technique as it was formed by Pesaran and Shin (Econometrics and economic theory in the 20th century. The Ragnar Frisch centennial symposium. Cambridge University Press, Cambridge, 1999) and Pesaran et al. (J Appl Econ 16:289–326, 2001) as well as the augmented Cobb-Douglas production function formed by Mankiw et al. (Quart J Econ 107:407–437, 1992). The results of ARDL test confirm the existence of long run relationship between examined variables. Capital seems to be an impetus of economic development both in the short and long run, while labor has a negative impact in Poland’s economic growth. However, trade openness and financial development found to be insignificant on economic development both in the short and long run. Finally, causality results showed that there is a unilateral causal relationship between financial development and labor towards economic development and also a bilateral causal relationship between capital and trade openness with economic development.

Economic Assessment of Lithium-Ion Battery Storage Systems in the Nearly Zero Energy Building Environment

Abstract: Scope of this paper is to deliver a complete techno-economic model for the economic assessment of lithium-ion battery energy storage systems in the framework of the nearly zero energy buildings (NZEB) The proposed model simulates the combined operation of photovoltaics, solar thermal generators, heat pump generators, electrical and thermal storage devices in order to represent efficiently the typical characteristics of NZEBs The model takes into account the thermal and electrical needs of the building, typical electricity prices, household electrical consumption profiles, weather data and typical costs for lithium battery energy storage systems Using these inputs, an optimization procedure is applied and the optimal size, in terms of net present value, for the lithium-ion battery energy storage system is derived

A Survey on Medium Access Control Schemes for 5G Vehicular Cloud Computing Systems

Abstract: Fifth generation (5G) vehicular systems support multiple services with strict Quality of Service (QoS) constraints. To fulfill the increased communication needs, 5G Vehicular Cloud Computing (5G-VCC) architectures with dense deployments of the access network infrastructures have been proposed. In such systems, the network resources manipulation is a critical task that could be addressed by the Medium Access Control (MAC) layer. MAC schemes that have been proposed for vehicular networks, can be applied to 5G-VCC systems in order optimal manipulation of communication resources to be accomplished. This paper makes an overview of available MAC schemes, while a comprehensive discussion about their implementation in 5GVCC systems is performed leading to useful conclusions.

Synthesis and characterization of lignite fly ash ceramic substrates coated with TiO 2 slurry, and evaluation in environmental applications

Abstract: The novel valorization of lignite combustion fly ashes in the development of ceramic substrates modified with ΤiΟ2 photocatalyst, with environmental benefits, was investigated. Disc-shaped compacts from fly ashes (either calcareous or siliceous) were sintered (1000 °C, 2 h), then coated with TiO2 slurry, and further thermally treated (400 and 500 °C, 1 h) to acquire TiO2 consistency onto the ceramic substrate. The ceramic microstructures were examined by XRD and SEM-EDAX. Their photocatalytic activity was examined in aqueous solutions of two organic dyes, methylene blue and methyl orange using visible and UV irradiation, with encouraging results. A synergistic effect between ash ceramic substrates and ΤiΟ2 enhances the properties of the final activated product. Pores occurring on the non-activated ash surface are to some extent covered by TiO2. As a result, the photocatalytic activity, rather than simple dye adsorption onto the surface of the coated substrates, is promoted leading to efficient dye decolorization. Higher dye removal is achieved in the case of methylene blue under cool daylight compared to methyl orange under UV (blacklight and blacklight blue). A major advantage of the process is the immobilization of TiO2 onto a cheap porous substrate, which can provide an alternative for the photocatalytic treatment of industrial effluents.

Digital Divide in Greece - A Quantitative Examination of Internet Nonuse

Abstract: During the last decade, the Internet take-up rate in Greece among individuals is much lower compared with the EU average. This paper investigates issues of the digital divide in Greece, by analyzing micro-data from the Eurostat ICT survey on household and individuals in 2012.