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Showing papers by "Technological Educational Institute of Western Macedonia published in 2016"


Journal ArticleDOI
TL;DR: A new optimized two-step hybrid block method for the numerical integration of general second-order initial value problems is presented, which is zero-stable and consistent with fifth algebraic order.
Abstract: A new optimized two-step hybrid block method for the numerical integration of general second-order initial value problems is presented. The method considers two intra-step points which are selected adequately in order to optimize the local truncation errors of the main formulas for the solution and the derivative at the final point of the block. The new method is zero-stable and consistent with fifth algebraic order. Numerical experiments used revealed the superiority of the new method for solving this kind of problems, in comparison with methods of similar characteristics in the literature.

144 citations


Journal ArticleDOI
TL;DR: The construction of trigonometrically fitted two step hybrid methods for the numerical solution of second-order initial value problems is considered and the coefficients of the modified methods are derived for the general case of s stages.

112 citations


Journal ArticleDOI
TL;DR: The comparison of FDASH against other rate adaptation schemes shows that the former successfully provides the client with the optimal video rates, avoiding buffer underflows and unnecessary changes of video resolution in case of fluctuations of the available connection throughput.
Abstract: The evolution of broadband connection technologies, along with the explosive growth of mobile handheld devices, has made video content one of the major Internet traffic types. HTTP adaptive streaming (HAS) is one factor assisting the growing popularity of Internet video. One of its standards, the MPEG dynamic adaptive streaming over HTTP (DASH), allows users to access video streams of multiple resolutions available at a central repository. Various adaptation algorithms using the MPEG DASH protocol have been proposed, aiming to adapt the media bit rate delivered at the client to the current network conditions. In this paper, we present the FDASH rate adaptation scheme that employs fuzzy logic to control the buffering time and the video resolution delivered to the client in order to distribute video segments of the best quality, deliver undisrupted video playback, and avoid frequent changes of video resolution. The comparison of FDASH against other rate adaptation schemes shows that the former successfully provides the client with the optimal video rates, avoiding buffer underflows and unnecessary changes of video resolution in case of fluctuations of the available connection throughput.

58 citations


Journal ArticleDOI
TL;DR: In this paper, an unpromoted and promoted 6.0-wt% MgO or CaO alumina supported nickel catalysts (8.0 -wt% Ni) were studied for the biogas reforming reaction.
Abstract: The energetic utilization of biogas, a gas mixture consisting mainly of CH4 and CO2 via the reforming or the dry reforming of methane reaction is of enormous interest as it converts these two greenhouse gases into synthesis gas (H2/CO mixtures). Nickel based catalysts have been extensively studied for both reactions, as they are highly active, but they suffer from fast deactivation by coking that can even lead to reactor blocking. It is thus desirable to learn more about their coking behavior, and their structural and catalytic stability. In this work, un-promoted and promoted with 6.0 wt% MgO or CaO alumina supported nickel catalysts (8.0 wt% Ni) were studied for the biogas reforming reaction. Supported nickel catalysts were synthesized following the wet impregnation method. The as synthesized Ni/Al2O3, Ni/MgO–Al2O3, Ni/CaO–Al2O3 samples were characterized by various techniques such as XRD, SEM, ICP and BET. Catalytic testing experiments were performed in a fixed-bed reactor at temperatures ranging from 500 to 850 °C and a feed gas mixture with a molar CH4/CO2 ratio of 1.5 simulating an ideal model biogas. It was concluded that the Ni/MgO–Al2O3 and Ni/CaO–Al2O3 catalysts exhibit higher values for XCH4, XCO2, YH2 compared to the ones of the Ni/Al catalyst for temperature ranging between 550 and 750 °C, while the opposite is evidenced for T > 750 °C. It was also evidenced that the presence of magnesium or calcium oxide in the support ensures a quite stable H2/CO molar ratio approaching to unity (ideal for the produced syngas) even for low reaction temperatures.

52 citations


Journal ArticleDOI
TL;DR: In this article, a local particle swarm optimization (PSO) variant algorithm is developed in order to define the optimal active and reactive power generation and/or consumption requirements for the optimal number and location of nodes that yield loss minimization.

43 citations


Journal ArticleDOI
TL;DR: In this paper, a 5 wt% Ni/La9.83Si4.5Fe1.5O26±δ catalyst was found to be active and up to 3.2 times more selective to H2 than a 5 Wt%Ni/Al2O3 catalyst, especially at low temperatures.
Abstract: In the glycerol steam reforming reaction a 5 wt% Ni/La9.83Si4.5Fe1.5O26±δ catalyst was found to be active and up to 3.2 times more selective to H2 than a 5 wt% Ni/Al2O3 catalyst, especially at low temperatures (<500 °C). A H2/CO molar ratio of 5 was achieved under a space velocity of 50000 h−1.

30 citations


Journal ArticleDOI
TL;DR: In this article, the performance of nickel, cobalt, and copper supported on silica as catalysts was evaluated for the glycerol steam reforming (GSR) reaction.
Abstract: The performance of nickel, cobalt, and copper supported on silica as catalysts was evaluated for the glycerol steam reforming (GSR) reaction. The samples were characterized by nitrogen-porosimetry according to Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), and inductively coupled plasma atomic emission spectroscopy (ICP-AES), while the deposited carbon on the catalytic surface was measured with a CHN-analyzer. Catalysts were studied in order to investigate the effect of the reaction temperature on (i) glycerol total conversion, (ii) glycerol conversion to gaseous products, (iii) hydrogen selectivity and yield, (iv) selectivity of gaseous products, and (v) selectivity of liquid products. The results showed that the Ni based on silica (Ni/Si) catalyst was more active and produced less liquid effluents than the catalysts that used an active metal such as Co or Cu. Moreover, the H2 yield from the Ni/Si catalyst was very close to the theoretical maximum predicted by thermodynamics, and the CO2 production was favoured in comparison to CO production, which is important for use in fuel cells.

22 citations


Journal ArticleDOI
TL;DR: In this article, the impact of H 2 as an additional reducing agent on the SCR of NO with C 3 H 6 in excess oxygen, was comparatively explored over low noble metal loading.
Abstract: The impact of H 2 as additional reducing agent on the SCR of NO with C 3 H 6 in excess oxygen, was comparatively explored over low noble metal loading (0.5 wt%), Pt/γ-Al 2 O 3 , Pd/γ-Al 2 O 3 , Ir/γ-Al 2 O 3 catalysts. To gain insight into the role of H 2 , the reactions NO + C 3 H 6 + O 2 (R#1), NO + C 3 H 6 + O 2 + H 2 (R#2), NO + H 2 + O 2 (R#3) were employed. In respect to propene oxidation, the Pd > Pt > Ir sequence was obtained under R#1, since they exhibit complete conversion at 220, 250, 325 °C, respectively; all metals exhibit moderate deNO x performances ( X NO, 2 co-presence (R#2) promotes both the NO and C 3 H 6 conversions, which is valid in the whole temperature interval investigated (50–400 °C), being more substantial for Pt/γ-Al 2 O 3 and Ir/γ-Al 2 O 3 , less beneficial for Pd/γ-Al 2 O 3 . A two-maxima feature is obtained on X NO pattern (at ∼100 and ∼230 °C) of Pt and Pd during R#2. The low temperature maximum −attributed to NO reduction by H 2 - is substantially more pronounced on Pt than Pd, offering X NO ∼90% and S N2 ∼85%; the high temperature maximum—attributed to NO reduction by C 3 H 6 —is higher by ∼15% on both Pt and Pd, in respect to the values obtained during R#1, while S N2 remained unaffected. Different X NO pattern with one maximum is obtained over Ir, implying a synergistic interaction between H 2 and C 3 H 6 . This synergy is accompanied by a substantial widening of the NO reduction window toward lower temperatures and a considerable increase on both X NO,max and S N2 (from X NO ∼30% with S N2 ∼55% during R#1 to X NO ∼70% with S N2 ∼95% during R#2). The specific features of all reactions and metals employed are comparatively discussed.

21 citations


Journal ArticleDOI
01 Nov 2016
TL;DR: In this paper, the authors focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria, and all the candidate fluids have been considered and all Rankine cycles examined were subcritical.
Abstract: Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

20 citations


Journal ArticleDOI
01 Nov 2016
TL;DR: The main focus of as discussed by the authors is to overview rare earth metals' overall impact on global economy and their environmental defects on soils during processing techniques and as they are used as fertilizers.
Abstract: Rare earth elements include the 14 lanthanides as well as lanthanium and often yttrium. Actually, most of them are not very rare and occur widely dispersed in a variety of rocks. Rare earth metals are vital to some of the world's faster growing industries: catalysts, Nd-magnets, ceramics, glass, metallurgy, battery alloys, electronics and phosphors. Worldwide, the main countries for distribution of rare earths deposits include China, USA, Russia, Brasil, India, Australia, Greenland and Malaysia. The mining and processing of rare earth metals usually result in significant environmental defects. Many deposits are associated with high concentrations of radioactive elements such as uranium and thorium, which requires separate treatment and disposal. The accumulation of rare earth elements in soils has occurred due to pollution caused by the exploitation of rare earth resources and the wide use of rare earths as fertilizers in agriculture. This accumulation has a toxic effect on the soil microfauna community. However, there are large differences in market prices due to the degree of purity determined by the specifications in the applications. The main focus of this article is to overview Rare Earth Metals' overall impact on global economy and their environmental defects on soils during processing techniques and as they are used as fertilizers.

20 citations


Journal ArticleDOI
TL;DR: A network selection method is proposed by applying the analytic network process to estimate the weights of the selection criteria, as well as a fuzzy version of technique for order preference by similarity to ideal solution to perform the ranking of network alternatives.
Abstract: Next generation wireless networks consist of many heterogeneous access technologies that should support various service types with different quality of service QoS constraints, as well as user, requirements and provider policies. Therefore, the need for network selection mechanisms that consider multiple factors must be addressed. In this paper, a network selection method is proposed by applying the analytic network process to estimate the weights of the selection criteria, as well as a fuzzy version of technique for order preference by similarity to ideal solution to perform the ranking of network alternatives. The method is applied to a heterogeneous network environment providing different QoS classes and policy characteristics. Each user applies the method to select the most appropriate network, which satisfies his or her requirements in respect of his or her service-level agreement SLA. Performance evaluation shows that when the user requests only one service, the proposed method performs better compared to the original technique for order preference by similarity to ideal solution, as well as the Fuzzy AHP-ELECTRE method. Moreover, the proposed method can be applied in cases where a user requires multiple services simultaneously on a device. The sensitivity analysis of the proposed method shows that it can be properly adjusted to conform to network environment changes. Copyright © 2014 John Wiley & Sons, Ltd.

Proceedings ArticleDOI
10 Apr 2016
TL;DR: In this paper, multilayered security architecture is defined based on defense in depth, in which the cloud infrastructure is divided into defense zones to achieve better security control and a secure architecture is applied.
Abstract: Cloud Computing constitutes an emerging computing paradigm consisting of elements of grid computing, utility computing and software-defined networks. The aggregation of these technologies offers a new environment for the deployment of services. Cloud computing environment provides capabilities which are unique covering the existing and future needs of organizations and companies. Moreover, this environment supports big data applications usually forming the core elements of research projects. Therefore cloud computing technology and big data are linked to each other. However, the capabilities of cloud computing environment create challenges concerning the security of data applications and its systems. In this respect, security issues are present on big data applications. By adopting the cloud computing environment, the provider has to incorporate security systems and policies in its infrastructure in order to mitigate the security threats. In this paper, multilayered security architecture is defined based on defense in depth. In this architecture the cloud infrastructure is divided into defense zones to achieve better security control. Additionally, intrusion detection system (IDS), honeypots and firewalls are incorporated alongside the defense mechanisms of the cloud infrastructure. In this way, a secure architecture is applied in which the end service is provided uninterrupted, while control over the level of security is maintained.

Journal ArticleDOI
01 Nov 2016
TL;DR: In this paper, the authors present a biological wastewater treatment plant with almost zero biomass production, less energy consumption and a practical way for operation control through microbial manipulation and microscopic examination, which is proved to be an important tool for evaluating plants' performance and assessing possible problems and symptoms.
Abstract: The sustainable operation of a biological wastewater treatment plant is significantly linked to its removal efficiency, cost of sludge management, energy consumption and monitoring cost. The biological treatment offers high organic removal efficiency, it also entails significant sludge production, which contains active (live) and inactive (dead) microorganisms and must be treated prior to final disposal, in order to prevent adverse impact on public health and environment. The efficiency of the activated sludge treatment process is correlated to an efficient solid-liquid separation, which is strongly depended on the biomass settling properties. The most commonly encountered settling problems in a wastewater treatment plant, which are usually associated with operating conditions and specific microorganisms growth, are sludge bulking, floating sludge, pin point flocs and straggler flocs. Sustainable management of sludge and less energy consumption are the two principal aspects that determine the operational cost of wastewater treatment plants. Sludge treatment and management accumulate more than 50% of the operating cost. Aerobic wastewater treatment plants have high energy requirements for covering the needs of aeration and recirculations. In order to ensure wastewater treatment plants' effective operation, a large number of physicochemical parameters have to be monitored, thus further increasing the operational cost. As the operational parameters are linked to microbial population, a practical way of wastewater treatment plants' controlling is the microscopic examination of sludge, which is proved to be an important tool for evaluating plants' performance and assessing possible problems and symptoms. This study presents a biological wastewater treatment plant with almost zero biomass production, less energy consumption and a practical way for operation control through microbial manipulation and microscopic examination.

Journal ArticleDOI
TL;DR: In this article, the authors present a control system of an experimental microgrid which is made compatible to bus communication technologies at the demand-side, by applying a simple technique, which does not require additional interface or software tools, as other methods do and therefore is a cost-effective method and can be easily expanded and used for demand side management in future smart grids.

Journal ArticleDOI
TL;DR: In this paper, the main characteristics and definitions of social capital and social network analysis (SNA) are reviewed and discussed, including the importance of content creation in attracting users to like and comment increasing engagement.
Abstract: The application of social network analysis in marketing can provide marketers with valuable insights for developing communication and branding strategies by building up social capital in social networking sites (SNSs) as Facebook. In this paper, the main characteristics and definitions of social capital and social network analysis (SNA) are reviewed and discussed, including the importance of social capital for marketing and branding in SNSs. SNA is used to analyse the network structure of a famous Greek brand page, and the activity (comments) of its members during a period of two months in 2013. The interactions between consumers, the content generated by the firm and the posts commenting on this content are presented and analysed in terms of SNA and marketing, highlighting the importance of content creation in attracting users to like and comment increasing engagement. The implications and applications of the use of SNA results and of social capital as a way of building brand loyalty in marketing decisions and planning are discussed, and suggestions for further research are offered.

Journal ArticleDOI
TL;DR: In this article, the authors present daily operation analysis of a low voltage network including a renewable supported microgrid, using a field-data based virtual test bed, daily variations in DG output power, residential demand and network voltages are simulated.

Journal ArticleDOI
TL;DR: Findings suggest LAB is an effective method for acceleration of HA formation on materials with low bioactivity, while cellular responses need further investigation.

Proceedings ArticleDOI
07 Jun 2016
TL;DR: In this article, the authors examined the contribution of the odd-order harmonic currents to the development of robust and distinct Load Signatures that could, in turn, facilitate load identification in NILM algorithms.
Abstract: This paper examines the contribution of the Odd-Order Harmonic Currents to the development of robust and distinct Load Signatures that could, in turn, facilitate load identification in Non-Intrusive Load Monitoring (NILM) algorithms. The analysis is based on field measurements in various residences with single-phase grid connections. Measurements have been conducted both for stand-alone operation of each appliance and for various combination scenarios. The former enables the determination of the active and reactive power consumption, the instantaneous current values, and the magnitude of odd-order harmonic current under steady state operation, for realistic operating conditions regarding the operational time of each appliance. The latter, allows considering candidate aggregated signals for decomposition. The results indicate that the utilization of more distinct and enhanced Load Signatures, using odd-order harmonic currents, improves the efficiency of the identification procedure.

Proceedings ArticleDOI
25 Sep 2016
TL;DR: A new system architecture and HTTP communication mechanism called Smart Barrel System (Wine-SBS) is proposed for the process of monitoring Debina varietal sparkling wine fermenting conditions, produced at the area of Zitsa Epirus, Greece.
Abstract: This paper proposes a new system architecture and HTTP communication mechanism called Smart Barrel System (Wine-SBS) for the process of monitoring Debina varietal sparkling wine fermenting conditions, produced at the area of Zitsa Epirus, Greece. The system includes microcontroller equipment with sensors that monitor wine attributes and storage conditions, called CBS-sensor transceivers, which are distributed among the debina fermentation vessels. The transmission of measurements, which occur periodically, are sent to a central cloud system application service. The CBS-sensor data are collected by a CBS-sensor collector and then follows an HTTP/2 request of multiplexed HTTP flows to a remote application server.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the effect of inflation and real wages on labor productivity for two European Union (EU) countries: Bulgaria and Romania using cointegration Autoregressive Distributed Lag (ARDL) test and causality test of Toda and Yamamoto (1995).
Abstract: This study examines the effect of inflation and real wages on labor productivity for two European Union(EU) countries: Bulgaria and Romania using cointegration Autoregressive Distributed Lag (ARDL) test and causality test of Toda and Yamamoto (1995). Results suggest that inflation reduces labor productivity. Moreover, the impact of wages on labor productivity is far greater the impact of inflation. Additionally, there exists unidirectional relation between inflation and real wages for Bulgaria, and real wages and labor productivity for Romania.

Journal ArticleDOI
01 Nov 2016
TL;DR: In this paper, a number of low-cycle fatigue tests were conducted on reinforced-concrete steel bars of various diameters to study their behavior under axial loading according to EN 10080 and EN 1421-3.
Abstract: A number of low-cycle fatigue tests were conducted on reinforced-concrete steel bars of various diameters to study their behaviour under axial loading according to EN 10080 and EN 1421-3. Scanning electron microscopy was used to study the specimen fracture surfaces. The problems faced during testing are presented and a specimen preparation method is described that will aid researchers on fatigue testing to obtain accurate test results and save on material and time.

Proceedings ArticleDOI
07 Dec 2016
TL;DR: This work considers trigonometrically fitted two derivative explicit Runge-Kutta methods of the general case that use several evaluations of f and g per step and provides numerical results to demonstrate the efficiency of these methods using four test problems.
Abstract: Trigonometrically fitted two derivative explicit Runge-Kutta methods are considered in this work. We give order conditions for trigonometrically fitted methods that use several evaluations of the f and the g functions. We present modified methods based on methods with several f evaluations and one g evaluation.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a model for predicting the factors that affect the grade of the bank rating by using seven groups of indicators: performance, size, ownership, corporate governance, capital adequacy or capital structure, sovereign country ranking, and loan growth.
Abstract: The crises of 2002 and 2008 have raised the issue of banking sector’s ranking system efficiency. The credit rating agencies (CRAs) are crucial for the modern financial market. The impact that the ratings have is indisputable. This paper is seeking to find the factors that affect the ratings and to create a prediction mechanism. The originality of the paper is based on the fact that it utilizes a number of different variables (ownership status, corporate governance, etc.), and the hypothesis is innovative because it addresses the issue of divergence–convergence of the European banking sector and its respective ratings. In order to do that, all ranking evaluations have been matched with a numerical value (i.e., AAA has value 24, A- has value 18, and B- has value 9). A good grade is considered to be above A- (value 18) and a bad grade below that number. Seven groups of indicators are examined: performance, size, ownership, corporate governance, capital adequacy or capital structure, sovereign–country ranking, and loan growth. Three econometric methods (probit, logit, and OLS) have been used to create a system that predicts the rating grade. The independent variable is binary (good grade = 1/bad grade = 0). Inactive banks have been excluded from the sample. This paper provides a model for predicting the factors that affect the grade of the bank rating. Many of the factors, which other studies have pointed out, are found to be statistically important in our models, too. This paper contributes to the literature by establishing a unique framework for the European banks and identifying the factors that affect the rating grade by giving an answer to the issue of an isomorphic banking sector in Europe. It shows that there are significant differences among the various geographical regions [variables cgsys, ns, European countries with major economic problems or those under stress (Portugal, Ireland, Spain, and Greece)].

Journal ArticleDOI
01 Nov 2016
TL;DR: In this article, the authors presented a design methodology which automates the generation of curves extracted from the point clouds that have been obtained by digitizing the physical objects, which leads to the development of customized products.
Abstract: This paper presents a design methodology which automates the generation of curves extracted from the point clouds that have been obtained by digitizing the physical objects. The methodology is described on a product belonging to the industry of consumables, respectively a footwear type product that has a complex shape with many curves. The final result is the automated generation of wrapping curves, surfaces and solids according to the characteristics of the customer's foot, and to the preferences for the chosen model, which leads to the development of customized products.

Journal ArticleDOI
01 Jan 2016
TL;DR: In this paper, the authors investigate customer value (CV) perceptions towards own-country Geographic Indication (GI) food products and examine if the perceived gains from purchasing of GI foods would exceed any perceived losses and shed light on the exact type of perceived values and costs that define CV for GI foods.
Abstract: This paper investigates Customer Value (CV) perceptions towards own-country Geographic Indication (GI) food products. CV perceptions are the outcome of the trade-offs between perceived Values and Costs from the purchase or consumption of a product. The objective is to examine if the perceived gains from purchasing of GI foods would exceed any perceived losses and shed light on the exact type of perceived values and costs that define CV for GI foods. Despite doubts in relation to specific search and experience parameters of GI foods that impact on the development of a good consumerproduct relationship, it is the positive perceptions about products’ quality, likeability and social status that mainly formulate CV. Concerns in relation to GIs’ price-availability are too mild, not subtracting much from the overall CV indicating that consumers are driven by more self-centred motives. For market success, GI food producers need to build stronger associations in consumers’ mind between GI foods and their altruistic value in terms of the ethical character of their production. KeywORdS Consumers, Costs, Geographic Indications, GI Foods, Perceptions, PLS, Relationships, Values

Book ChapterDOI
01 Jan 2016
TL;DR: The credit cooperative system was introduced into the Greek banking system at the beginning of the 1990s and has developed remarkably with regards to the number of cooperative banks, geographic regions and banking operations.
Abstract: The credit cooperative system was introduced into the Greek banking system at the beginning of the 1990s. According to Greek Law, the credit cooperative system is distinguished between cooperative banks and credit cooperatives. Cooperative banks are banking institutions, while credit cooperatives are not banking institutions and cannot offer banking services. Since its establishment, the credit cooperative system has developed remarkably with regards to the number of cooperative banks, geographic regions and banking operations. Some cooperative banks exhibit much higher development in comparison to others. On a national level, cooperative banks have a limited position in the Greek banking sector concerning assets and branches. This is primarily due to the restrictions imposed on the credit cooperative system by the Greek legislative framework and the absence of cooperative banks in Greece’s two main urban centers. The Greek credit cooperative system is characterized by its autonomy based on independent local cooperative banks. These banks undertook efforts to create a nationwide non-cooperative bank.

Journal ArticleDOI
TL;DR: The unusual increase of the CH3/SiO2 clathrates EPR spectral width with temperature over approximately 120 K has its origin in repeated angular momentum vector alterations due to frequent collisions with the clathrate void walls between periodical free rotation periods.
Abstract: EPR line shape simulations of CH3/SiO2 clathrates and comparison to CH3/N2O and CH3/SiO2 experiments reveal the motional conditions of the CH3 radical up to the unusual regime of its stability, the high-temperature diffusional regime, at 300 K. In the low-temperature region, the CH3 in clathrates is found to rotate around the in-plane axes even at as low temperatures as 3.8 K. However, nonrotating methyls performing only libration about the C2-axes as well as around the C3-axis are also found, proving the existence of special sites in the clathrate voids that begin to accumulate a significant fraction of methyl radicals at temperatures below approximately 7 K. A distinctive feature in the spectrum anisotropy and line width temperature profiles is found nearby 25 K, which is interpreted as the radical physisorption inside the voids that occurs with the sample temperature lowering. The unusual increase of the CH3/SiO2 clathrate EPR spectral width with temperature over approximately 120 K has its origin in r...

Journal ArticleDOI
TL;DR: In this paper, the promoting impact of potassium (0-1/wt% K) on nitrous oxide (N2O) catalytic decomposition over Ir/Al2O3 is investigated under both oxygen deficient and oxygen excess conditions.
Abstract: The promoting impact of potassium (0–1 wt% K) on nitrous oxide (N2O) catalytic decomposition over Ir/Al2O3 is investigated under both oxygen deficient and oxygen excess conditions All samples were characterized by means of X-ray powder diffraction (XRD), temperature-programmed reduction (H2-TPR), ammonia desorption (NH3-TPD) and Fourier Transform Infrared Spectroscopy of pyridine adsorption (FTIR-Pyridine) The results reveal that the K-free Ir/Al2O3 catalyst consists mainly of the IrO2 phase, exhibiting also significant Lewis acidity, which is gradually eliminated by the addition of K Catalytic performance results showed that the deN2O performance in the absence of O2 in the feed mixture is negatively affected upon increasing potassium loading However, under oxygen excess conditions, a pronounced effect of K is observed Although the catalytic performance of the un-doped catalyst is drastically hindered by the presence of O2, the K-promotion notably prohibits the oxygen poisoning The optimum deN2O performance under oxygen excess conditions is obtained with potassium loading of 05 wt% K, which offers complete conversion of N2O at 580 °C, instead of the corresponding 50 % N2O conversion achieved with the un-modified sample On the basis of characterization results, it was concluded that alkali-doping in combination with oxygen excess conditions are required towards the formation of active Ir entities

Book ChapterDOI
01 Jan 2016
TL;DR: In this article, the authors investigated the effectiveness of Web 20 applications in terms of citizens' awareness, interest, and engagement in Greek local government by investigating the usage and effectiveness of web 20 applications employed by the 325 Greek local governments.
Abstract: Are Greek local governments moving towards e-government 20 model? What are the factors that impact adoption of Web 20 tools? What is the effectiveness of these tools in terms of citizens’ awareness, interest, and engagement? The present study addresses these questions by investigating the usage and effectiveness of Web 20 applications employed by the 325 Greek local governments Results indicate that local authorities in Greece are moving towards an e-government 20 era, albeit slowly Local governments originating from municipalities with a large number of educated inhabitants who have made use of e-government services are more likely to be adopters of Web 20 tools In addition, findings suggest that Greek citizens are beginning to be more aware of the Facebook pages of their local governments while they seem more interested in their YouTube channels Hopefully, local governments can increase their citizens’ engagement by being active on Facebook Officials of local governments should increase their presence on social media such as Facebook and YouTube but their strategies should be differentiated for each social medium in order to benefit from their potential

Journal ArticleDOI
01 Nov 2016
TL;DR: In this article, the authors demonstrate a 7-step methodology that describes the way nature can act as a source of inspiration for the design and the development of a product and suggest special computerized tools and methods for the product optimization regarding its environmental impact.
Abstract: The aim of this study is to demonstrate a 7-step methodology that describes the way nature can act as a source of inspiration for the design and the development of a product. Furthermore, it suggests special computerized tools and methods for the product optimization regarding its environmental impact i.e. material selection, production methods. For validation purposes, a garden chaise lounge that imitates the form of a scorpion was developed as a result for the case study and the presentation of the current methodology.