bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Participation in International R&D Networks Enhance Local Dynamism?
Authors: Güler Hüseyin , Erdil Erkan
Published: August 2015

This chapter which is in line with the global pipelines-local buzz framework addresses the collaboration dynamics of ICT researchers from universities of an emerging economy who are mostly benefiting from national funds and do not have dominating or core roles in international R&D networks. It provides a novel taxonomy to identify the degree of globalisation versus localisation of ICT scientists in Turkey. Based on international and national project portfolios of Turkish ICT researchers who participated in FP6 and other international projects between 2003 and 2006, four groups (gatekeepers, externally oriented researchers, internally oriented researchers, inactive researchers) were formed in terms of their degree of local or global focus. For the period of 2007–2013, the performance of the same population was traced with respect to its international or national project density, publication output, involvement in decision making processes on academic project funding, and contribution to R&D capacity development in the private sector. Findings show that that most of the researchers who are engaged in international collaboration are also locally active and they seem to be the most productive actors within the four groups. The study also implies that having a strong project portfolio at both national and international levels relates to having a work experience abroad after the PhD fulfilment and being at a university with advanced research ecosystem in Turkey. This chapter concludes with key policy recommendations, highlighting the need on moving beyond one-size-fits-all policies which should take in to account the heterogeneity, differentiation on career levels, national priorities and capacity requirements of the research ecosystem.
Regional Landfill Site Selection with GIS and Analytical Hierarchy Process Techniques
Authors: Shamshiry Elmira , Abdulai Abdul Mumin , Mokhtar Mazlin Bin , Komoo Ibrahim
Published: August 2015

Increasing population and urbanization pose a huge challenge for municipal authorities to select suitable landfill site to dispose the increasing quantities of solid waste. Wrong landfill siting can result in social, environmental and economic cost. Therefore, suitable approaches are required to select landfill sites because that can enhance sound waste disposal practice in the fast-growing urban areas. The Geographic Information System based Multi-criteria Decision Analysis has been used in this chapter to examine the essentials of an effective site selection. GIS-based MCDA is an intelligent system that transforms spatial data into valuable information which can be used to make critical decisions. The analytical hierarchy process is utilized to assist the prioritization process. In Langkawi, disposal of municipal solid waste into open sites could lead to different adverse impacts on public health and the physical environment. This paper represents simple but effective method to assist landfill site selection efforts in the Langkawi.
The Current State of Dialogue in South African Universities
Authors: Johnston Kevin Allan , Nogemane Bane , Kabanda Salah
Published: August 2015

The current state of dialogue within certain South African universities was explored, and if and how dialogue can be used to address the issues of transformation and the lack of social cohesiveness. The role of Information and Communication Technologies (ICTs) in facilitating or inhibiting open conversations was examined. Through qualitative analysis of surveys administered to staff and students at universities, the researchers identified that power disparity, and the slow pace of transformation were prevalent and needed to be addressed. University management generally practice open conversations, and students and staff were willing to participate. Organisational structures were not conducive for open conversations. The ICT infrastructure used had no significant role to play, while Social Network Systems (SNSs) were perceived as enablers of open conversations. This chapter contributes to the existing body of knowledge about change management, and presents open conversations as a means of driving and realising organisational change.
An Analysis of the Characteristics and Dynamic Development of an Emergent Sustainable Hotel Business Model in Italy
Authors: Camillo Angelo , Presenza Angelo , Di Virgilio Francesca
Published: August 2015

This chapter introduces the concept of “Albergo Diffuso” (Diffused Hotel), (AD). A hotel typology that is emerging as a sustainable accommodation with the potential to compete and establish itself as a viable hotel business. To raise awareness about the concept we analyze the scarce literature available and the rather limited publicly available resources provided by the Association of Albergo Diffuso (AAD). We also conducted non-intrusive observations through personal on-location investigative visits of various ADs operations. We present a sample guests' satisfaction ratings of the concept by conducting a web content analysis of the Trip Advisor's website, a hotel rating platform, on the Residenza Sveva, an Albergo Diffuso property located in the city of Termoli, in the Region of Molise in South Central Italy. The data shows that this concept is patronized largely by couples but also by business travelers. The site gives this property a 4.5 / 5 star rating.
The Influence of National Culture and Organizational Culture on the Success of an Expatriate Overseas Assignment
Authors: Causin Gina Fe G. , Ngwenya Charito G.
Published: August 2015

Numerous studies have attempted to determine what makes hospitality expatriate executives successful and a large variety of managerial skills have been generated. The rapidly increasing trend toward internationalization of business has fostered an interest in examining important management skills that international hospitality executives should possess. The study findings indicated that there were underlying dimensions that contributed to the success of hospitality expatriate executives on their overseas assignment. National culture and corporate using management skills could influence a successful overseas assignment. However, it was not revealed which one between the two dimensions has more influence towards a successful overseas assignment. Successful expatriates are being profiled as organizations have found that expatriate assignments are an effective, yet expensive, means of developing international qualities in their managers. The increasing globalization of business appears to have led to the emergence of an international business workforce that shares a unique set of cultural beliefs, attitudes, and behaviors. The thrust of this chapter was to examine the influence of national culture and corporate culture of hospitality expatriate executives that led to a successful overseas assignment.
Diversity in Hotel Industry
Authors: Georgiadou Andri , Iasonos Chryso
Published: August 2015

Managing human resources in the hospitality industry is a challenging task. In today's competitive environment, an increasing number of organizations invest in promoting diversity in the workplace. The concept of diversity as a value is based on the recognition, acceptance, and respect. It implies understanding that each individual is unique and recognizing and valuing the individual differences. Therefore, it is very important to understand “how diversity impacts individual and team processes and outcomes in the workplace”. This chapter introduces the notion of diversity in hotel industry: its role, its interrelationship with satisfaction and teamwork. Emphasis is given on the fact that the right to difference and diversity should be incorporated not only in the whole range of processes, strategies, and actions of the company but also within the corporate culture.
The Impact of Integrated Marketing Communications on Hotel Brand Equity
Authors: Šerić Maja , Gil-Saura Irene , Mollá-Descals Alejandro
Published: August 2015

The Integrated Marketing Communications (IMC) approach appeared as a response to the need for more sophisticated marketing communication discipline in a confusing tourism marketing environment. This chapter examines the impact of IMC on the hotel brand equity dimensions, i.e. brand image, perceived quality, and brand loyalty. Moreover, it estimates the moderating effect of national culture on the relationships examined. The study is approached from the customer perspective and uses survey methodology to assess guests' perception of IMC and brand equity in the hotel contexts. In particular, 335 hotel guests participated in the empirical investigation while staying in high-quality hotels in Rome, Italy. The findings reveal that IMC exerts a positive impact on hotel brand equity. Furthermore, the inter-relationship exists between the three dimensions of hotel brand equity. In general, national culture does not exert a significant impact within the posited model.
Staff Turnover at the Crossboarder Hotel Company
Authors: Camillo Angelo , Di Virgilio Francesca , Di Pietro Loredana
Published: August 2015

This chapter endeavors to draw attention to staff turnover in the hospitality industry by analyzing a company, which will be referred to as “Crossboarder Hotel Company”. The actual name has been disguised to maintain the company's confidentiality. The chapter discusses the causes and effects of employee turnover and ways to prevent turnover. Turnover is divided into three categories: job dissatisfaction, errors in employee selection, and poor management. The common cause of turnover however; is job dissatisfaction which affects employees well-being. A survey instrument that included measures of job satisfaction, and demographic information was used to collect information from hotel employees of an American Hotel Chain we refer to as the “Crossboarder Hotel Company”, geographically dispersed in Georgia, Alabama, California, North Carolina, Arizona, Texas, Utah, and Indiana. Data from 78 respondents were collected over a three-year period. The results show that favouritism, nepotism, lack of responsibility and accountability, lack of training and improper communication negatively contributed to job satisfaction.
Management in Modern Organizations
Authors: Sousa Maria José , Moço Isabel
Published: August 2015

The starting point for this chapter was to bring together the research fields of organizational theories, innovation and change and knowledge management. The focus was on innovation in the perspective of organisational studies and the process of knowledge sharing in organisations. The main idea was not to create an historical framework of these theories but to use them as analytical models. The chapter begins with a description of the main features of organisational theories, including navigation in organisational innovation context: types of organisational innovation and nature of innovation. It also includes the conceptualization that individual knowledge is a critical source of organisational knowledge and explores the link between individual knowledge use and organisational innovation processes. This literature review tries to create a frame for the organisational innovation process. In this context it was important to analyse its implications to the effective use and share of individual knowledge, linking it to the knowledge management theories. However the importance of organisational innovation for competitiveness is not explicit and the choice between investing in technology and investing in people always raises some questions about short and long term survival of the organisations – being the new digital configuration of organizations another way to reach organizational success.
Organisational Architecture and Learning in an Inter-Professional Context
Authors: Bishop Jonathan
Published: August 2015

Designing an effective organisational architecture for an undertaking can be considered essential to its success. The way an organisation is designed – or otherwise appears to its workers – will affect the extent to which those workers associated with it can be effective at their jobs. This chapter undertakes a case study into an organisation that is based around contingent working and inter-professionalism. Important things drawn from the study include the importance of the Cloud to distance working, such as teleworking; the identity of the organisation and how workers relate to it; as well as what factors assist on inhibit worker motivation. The study concludes that the organisational structure of the organisation investigated – where different firms perform different tasks, could be seen as best practice in supporting inter-professional environments.
Financial Market Infrastructures
Authors: Diehl Martin
Published: August 2015

Like a human being's backbone, well-functioning financial market infrastructures contribute to the stability of the financial system. They enable fast and smooth movements, channel relevant information, protect the channels for transmission and reduce risk. Problems in financial market infrastructures may lead to dysfunctions of financial markets, a lack of options for transaction and, therefore, to limited movability, misleading information or disturbed information channels and in the worst case to systemic risk. The chapter explains the role of financial market infrastructure within the wider definition of a financial system. Based on the historical emergence of payment systems, central clearing and central securities depositories, the special advantage of financial market infrastructures for the productivity of intermediaries, for the efficiency of financial markets and for the welfare of an economy is explained. The chapter shows the economic and analytical importance and specificity of financial market infrastructures.
Payment System Analysis
Authors: Müller Alexander Pascal
Published: August 2015

Together with the growing importance of stable and efficient payment systems, payment systems analysis has gained importance in the recent years. Central banks play the most prominent role in this field since they have unique responsibilities but also unique opportunities. This chapter will systematize the different aspects of payment system analysis and show their respective importance from a central bank perspective. This will be done both from a theoretical but also from a practical point of view by giving examples of actual work in this field. Three types of Payment system analysis will be distinguished: Payment system analysis in the broad sense of the term, the analysis of particular payment systems and the use of payment system data.
The Changing Role of CSDs in the Post-Trade Industry in Europe
Authors: van Wageningen Ariena
Published: August 2015

In this chapter Central Securities Depositories (CSDs) are analyzed, in playing an essential role in the European post-trade market. The background is presented, describing their services both on domestic level, and in a cross border context in Europe. CSDs have introduced (self) regulation and this chapter outlines the efforts they are making to remove existing barriers in a still fragmented European post-trade market, in order to achieve more efficiency. Particular attention is given to the changes and challenges the CSDs face with respect to the Central Security Depository Regulation (CSDR) and Target2-Securities (T2S), which is an initiative of the Eurosystem and is expected to go live as of June 2015. T2S will connect CSDs within the European area, performing as a cross border securities settlement engine.
Using Massively Multiplayer Role Playing Games (MMORPGs) to Support Second Language Learning
Authors: Strachan Rebecca , Kongmee Isara , Pickard Alison
Published: August 2015

Massively Multiplayer Online Role Playing Games (MMORPGs) create large virtual communities. Online gaming shows potential not just for entertaining, but also in education. This case study investigates the use of commercial MMORPGs to support second language teaching. MMORPGs offer virtual safe spaces in which students can communicate by using their target second language with global players. Using a mix of ethnography and action research, this case study explores the students' experiences of language learning and performing while playing MMORPGs. The results show that the use of MMORPGs can facilitate language development by offering fun, informal, individualised and secure virtual spaces for students to practise their language with native and other second language speakers.
Participation and Interaction in Learning Environments
Authors: Casquero Oskar , Benito Manuel , Romo Jesús , Ovelar Ramón
Published: August 2015

It is commonly argued that learner participation and interaction can be enhanced by the use of Personal Learning Environments (PLEs). However, this idea has yet to be reflected in practice. In this sense, researchers are encouraged to do more empirical research in order to know whether PLEs could allow the transference of the participative and networked nature of Web 2.0 to the institutional sphere. In this sense, this paper presents a differential study in which the authors analyzed student participation and interaction when working with a Virtual Learning Environment (VLE) and a PLE in two online, higher education courses. With that aim in mind, participation measures were calculated and social network analysis was performed on the digital data collected from the learning environments. The findings reflect the effectiveness of a PLE over a VLE for facilitating student participation and for assisting students in the creation of more cohesive learning networks.
Conceptualising Recognition of Prior Learning Processes in the Age of Open Learning
Authors: Ruinard Elizabeth , McNamara Judith
Published: August 2015

This chapter interrogates what recognition of prior learning (RPL) can and does mean in the higher education sector—a sector in the grip of the widening participation agenda and an open access age. The chapter discusses how open learning is making inroads into recognition processes and examines two studies in open learning recognition. A case study relating to e-portfolio-style RPL for entry into a Graduate Certificate in Policy and Governance at a metropolitan university in Queensland is described. In the first instance, candidates who do not possess a relevant Bachelor degree need to demonstrate skills in governmental policy work in order to be eligible to gain entry to a Graduate Certificate (at Australian Qualifications Framework Level 8) (Australian Qualifications Framework Council, 2013, p. 53). The chapter acknowledges the benefits and limitations of recognition in open learning and those of more traditional RPL, anticipating future developments in both (or their convergence).
Considerations of Self in Recognising Prior Learning and Credentialing
Authors: Robertson Lloyd Hawkeye , Conrad Dianne
Published: August 2015

Discussions about recognition of prior learning (RPL) and credentialing frequently focus on issues of equivalency and rigour, rather than the effects of assessment on self-structure. Yet, such processes invite reflexive self-assessment that results in either a conformational or destabilising effect on self-identity. Those interested in RPL therefore need to understand how the process impacts on self and how learner needs associated with those impacts may be met. This chapter explores the self as a sub-text within the RPL process and argues that learners should be viewed as holistic and complex beings and that educational strategies can meet multiple objectives that extend beyond the educational domain, potentially creating an overlap with learners' mental health. The authors encourage policies and practices that validate the individual and enhance the possibility of developmental self-growth. A learner-centred ethic that meets the dual needs of learners to obtain credit and achieve self-development is proposed.
Applying Genre-based and L2 Pragmatic Instruction to Teaching Oral Presentations on the Web
Authors: Huang Hung-Tzu , Chang Yu-Jung
Published: August 2015

This article describes the development of an Internet-based instructional platform, which aims to guide EFL college students in learning and practicing oral presentation skills. Genre-based instruction and insights from L2 pragmatic instructional research inspired the platform's design. The instructional units in the online platform engage learners in a comparative analysis of rhetorical and language features at both expert speaker and learner speech levels and scaffold the learners in utilizing these features to deliver practice presentations. Documenting the four EFL students' experiences using the platform, the user reports show how the guided tasks expanded the students' understanding of ‘good presentations.' For learners whose language-learning goals are directed towards participating in a global community, it is suggested that key factors in developing web-based oral presentations materials are corpus selection and pedagogical tasks, which consider the learners' subjectivity in determining rhetorical and pragmatic norms.
Building Data Warehouses Using Automation
Authors: Rahman Nayem , Rutz Dale
Published: August 2015

Software development is a complex endeavor. While significant benefits can be achieved, the process is often laborious, time consuming and error prone requiring multiple iterations in order to achieve the desired result. Issues arise for numerous reasons – coding defects, unclear requirements, migration challenges, lack of convention, and inadequate testing to name a few. When convention and automation are introduced into the software development lifecycle there are significantly fewer opportunities for failure. Automation also allows for shorter development windows. Generally there are fewer errors throughout testing, with the bulk of those being found in unit and functional testing, far before the users get involved in systems acceptance testing. A data warehouse consists of multiple subject areas in which many tasks are common and should be automated for the sake of efficiency and enforcing convention. This article discusses a set of tools that can be used to automate writing data warehouse objects. The article also provides statistics of time saved using automation.
Complex Role Inclusions with Role Chains on the Right are Expressible in SROIQ
Authors: Compton Michael
Published: August 2015

The syntax of both SROIQ and OWL 2 allow complex role inclusion axioms where the role composition occurs on the left of the subsumption relation, but not where the role composition occurs on the right. This paper proves that, despite the lack of syntax, SROIQ, and consequently OWL 2, can already express such complex role inclusions. This is shown by proving that complex role inclusion axioms where the role composition occurs on the right of the subsumption relation can already be expressed in terms of complex role inclusions on the left. The resulting syntactic restrictions are similar to those already present in SROIQ and OWL 2.
Wrapper Feature Selection based on Genetic Algorithm for Recognizing Objects from Satellite Imagery
Authors: Hewahi Nabil M. , Alashqar Eyad A.
Published: August 2015

Object recognition is a research area that aims to associate objects to categories or classes. The recognition of object specific geospatial features, such as roads, buildings and rivers, from high-resolution satellite imagery is a time consuming and expensive problem in the maintenance cycle of a Geographic Information System (GIS). Feature selection is the task of selecting a small subset from original features that can achieve maximum classification accuracy and reduce data dimensionality. This subset of features has some very important benefits like, it reduces computational complexity of learning algorithms, saves time, improve accuracy and the selected features can be insightful for the people involved in problem domain. This makes feature selection as an indispensable task in classification task. In this work, the authors propose a new approach that combines Genetic Algorithms (GA) with Correlation Ranking Filter (CRF) wrapper to eliminate unimportant features and obtain better features set that can show better results with various classifiers such as Neural Networks (NN), K-nearest neighbor (KNN), and Decision trees. The approach is based on GA as an optimization algorithm to search the space of all possible subsets related to object geospatial features set for the purpose of recognition. GA is wrapped with three different classifier algorithms namely neural network, k-nearest neighbor and decision tree J48 as subset evaluating mechanism. The GA-ANN, GA-KNN and GA-J48 methods are implemented using the WEKA software on dataset that contains 38 extracted features from satellite images using ENVI software. The proposed wrapper approach incorporated the Correlation Ranking Filter (CRF) for spatial features to remove unimportant features. Results suggest that GA based neural classifiers and using CRF for spatial features are robust and effective in finding optimal subsets of features from large data sets.
Role of Karaka Relations in Hindi Word Sense Disambiguation
Authors: Singh Satyendr , Siddiqui Tanveer J.
Published: August 2015

Karakas are an important constituent of Hindi language. Karaka relations express syntactico-semantic or semantico-syntactic relationship between verbs and nouns or pronouns in a sentence. They capture certain level of semantics closer to thematic relations, but different from it. A vibhakti is assigned to each karaka, in Paninian grammar. This paper investigates the role of karaka relations in Hindi Word Sense Disambiguation (WSD) by utilizing vibhaktis. Two supervised WSD algorithms were used for disambiguation. The first algorithm is based on conditional probability of co-occurring words and the second algorithm is Naïve Bayes (NB) classifier. The first algorithm utilizes various heuristics for analyzing the role of karakas in Hindi WSD. The authors obtained an improvement of 14.86% in precision by utilizing content words, vibhaktis and phrases containing them in context vector over the context vector of content words after dropping vibhaktis. A gain of 6.91% in precision was observed by using content words and vibhaktis in context vector over the context vector of content words after dropping vibhaktis of similar context window size. The authors obtained maximum precision of 50.73% by extracting vibhaktis in a ±3 window using WSD algorithm based on conditional probability of co-occurring words. They obtained maximum precision of 56.56% by extracting vibhaktis in a ±4 window using NB classifier.
Damage Index Proposals Applied to Quasi-Fragile Materials Simulated Using the Lattice Discrete Element Method
Authors: Rodrigues Rodolfo S. , Birck Gabriel , Iturrioz Ignacio
Published: August 2015

The process of damage in quasi-fragile materials is characterized by loss of isotropy for certain load levels, the strain localization, the cooperative effect between damaged regions and the avalanche of ruptures are particular features in the damage process of this kind of material. This behavior is not easy to represent with a continuous approach. In the present work a version of the Lattice Discrete Element Method (LDEM) is employed. This methodology allows the simulation of fracture and fragmentation in natural way. Different indexes will be shown to perform the measurement of the damage evolution in the context of LDEM. The performance of these indexes to evaluate the damage evolution is discussed in this paper.
Heterogeneous Lattice Model Based Simulation of Concrete under Uniaxial Loading
Authors: Yan Xiao Huan , Ren Xiao Dan , Li Jie
Published: August 2015

The heterogeneous lattice model is presented to simulate the behaviors of concrete, in which the concrete is regarded as random medium and the stochastic damage constitutive model is proposed. The parameters of the stochastic damage constitutive is identified compared with the experiment results of concrete under uniaxial tension and uniaxial compression.
Phenomenological Modelling of Impact Toughness Transition Behaviour
Authors: Münstermann Sebastian , Kucharczyk Pawel , Golisch Georg , Döbereiner Benedikt
Published: August 2015

The toughness transition behavior of ferritic steel results from the fact that two competing fracture mechanisms can be activated independently or progressively. Temperature, strain rate and the material ́s hardening properties are the major influences affecting the result of this competition between cleavage and ductile fracture mechanisms. An elastic visco-plastic plasticity model with stress-state dependent yielding and isotropic hardening forms the basis of a model to predict the Charpy impact toughness properties of steels with bcc crystal structure for transition behavior. A scalar damage variable is coupled into the yield potential in order to capture the effects of damage induced softening. The corresponding damage evolution law considers damage initiation criteria for both mentioned fracture mechanisms. Material parameter identifications and successful model application in terms of Charpy impact toughness tests are demonstrated.
Comparison of Two Time-Integration Algorithms for an Anisotropic Damage Model Coupled with Plasticity
Authors: Wulfinghoff Stephan , Fassin Marek , Reese Stefanie
Published: August 2015

In this work, two time integration algorithms for the anisotropic damage model proposed by Lemaitre et al. (2000) are compared. Specifically, the standard implicit Euler scheme is compared to an algorithm which implicitly solves the elasto-plastic evolution equations and explicitly computes the damage update. To this end, a three dimensional bending example is solved using the finite element method and the results of the two algorithms are compared for different time step sizes.
Variational Approach to Dynamic Brittle Fracture via Gradient Damage Models
Authors: Li Tian Yi , Marigo Jean Jacques , Guilbaud Daniel , Potapov Serguei
Published: August 2015

In this paper we present a family of gradient-enhanced continuum damage models which can be viewed as a regularization of the variational approach to fracture capable of predicting in a unified framework the onset and space-time dynamic propagation (growth, kinking, branching, arrest) of complex cracks in quasi-brittle materials under severe dynamic loading. The dynamic evolution problem for a general class of such damage models is formulated as a variational inequality involving the action integral of a generalized Lagrangian and its physical interpretation is given. Finite-element based implementation is then detailed and mathematical optimization methods are directly used at the structural scale exploiting fully the variational nature of the formulation. Finally, the link with the classical dynamic Griffith theory and with the original quasi-static model as well as various dynamic fracture phenomena are illustrated by representative numerical examples in quantitative accordance with theoretical or experimental results.
Using Acoustic Emission Monitoring to Observe the De-Bonding Behavior of Rebar in Cyclic Pull-Out Tests
Authors: Pei Kuang Chih , Kan Yu Cheng
Published: August 2015

This research aimed to reveal the bond behavior and failure mechanism of varying size rebar embedded in concrete with inside pre-crack through a series of quasi-static/cyclic pull-out tests and real-time acoustic emissions monitoring (AE). The obtained AE signal density records of the tests provide potential usage for evaluate the safety of reinforced concrete (RC) structure subjected to cyclic load, as well as quantitative study in the remaining life of RC after earthquake or shake damage.
Development of Unified Viscoplastic-Damage Model for Crashworthiness Analysis of Boron Steel Safety Components with Tailored Microstructures
Authors: Li Nan , Lin Jian Guo , Dean Trevor A.
Published: August 2015

Hot stamped boron steel panels with tailored properties are popular as car safety components for maximised energy absorption. In this study, dynamic and quasi-static tensile tests (strain rate: 0.001/s – 500/s) combined with microstructural observation were carried out to study the mechanical properties of press hardened boron steel with various microstructures (martensite volume fraction: 0 – 100%) at room temperature. Based on the test results, a physically-based unified viscoplastic-damage constitutive model has been developed and determined, which takes the volume fraction of martensite into account. Thus the crashworthiness and failure mode of boron steel parts having graded microstructure distributions can be described through a single set of equations.
The Effects of Water Removal Process on the Properties of Magnesium Aluminate Spinel Nanopowders Synthesized by Co-Precipitation Method
Authors: Teerasoradech Sarut , Serivalsatit Karn
Published: August 2015

Magnesium aluminate spinel (MgAl2O4) or spinel ceramics have been widely used in engineering fields due to its attractive properties, such as high mechanical strength, good optical properties, and high refractoriness. Precipitation is one of the most common techniques for preparing spinel nanopowders because it offers many advantages including low cost, simple method, and ease of mass production. However, severe agglomeration usually takes place during water removal process, i.e. washing and drying. These hard agglomerates deteriorate sinterability of nanopowders. In this study, spinel nanopowders were prepared by co-precipitation method. The remaining water in the precipitated precursor was removed by washing the precipitated precursor with organic solvents, i.e. ethanol and acetone-toluene-acetone. Conventional drying process was also performed for comparison. The characteristics of the obtained spinel nanopowders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) method. The results showed that the water removal process did not have any significant effects on phases of the dried precursors and the calcined powders. However, washing the precipitate precursor with organic solvent is the most effective process to prepare spinel nanopowders with low degree of agglomeration. Whereas, removing water by conventional drying process led to the formation of hard agglomerates. Furthermore, the effects of water removal process on sinterability of the spinel nanopowders were also reported.
The Study of Physical and Thermal Conductivity Properties of Cement Paste Containing Nanosilica
Authors: Jittabut Pongsak , Chindaprasirt Prinya , Pinitsoontorn Supree
Published: August 2015

This research was presented the physical and thermal conductivity properties of cement pastes containing nanosilica by mixing three nanosilica particle sizes of 12, 50 and 150 nm, using nanosilica of 1-5 wt%. The water-cementitious ratio (W/C) was 0.5 for all samples. Thermal property coefﬁcients were tested using a direct measuring instrument with surface probe (ISOMET2114). The influence of nanosilica on the physical properties were compressive strength, bulk density, XRD and SEM respectively. The results indicated that the use of nanosilica as an admixture can reduce the thermal conductivity and lowered the bulk density of specimen. The cement paste with nanosilica particle size of 50 nm with 4 wt% nanosilica at the age of 28 days showed the optimized properties. The thermal conductivity was lowest at 0.913 W/m-K, the compressive strength was highest at 51.62 MPa and the bulk density was 1,806 kg/m3respectively. The compressive strength increases more than 50% higher than that of pure paste. The cement pastes with nanosilica particle sizes of 50 and 150 nm, have lower unit weight and thermal conductivity than typical control cement paste about 9% and 15% respectively. The nanosilica mixed cement paste is very interesting for energy saving when used as wall insulating material.
Effect of Crystallinity of Hydroxyapatite Nanoparticles Prepared from Bovine Bone on Adsorption of Ammonia Gas
Authors: Choochaisangrat Thonnisorn , Powduang Teerasak , Kuanchertchoo Neeranut , Kashima Dujreutai Pongkao
Published: August 2015

The adsorption of ammonia gas on nanoparticle hydroxyapatite (HA) prepared from bovine bone was investigated. HA is well known as a good adsorbent for both of gas and liquid adsorbate. In this study, bovine bone was cleaned, calcined at 700 °C for 4 hrs and subsequently ground. The ground bovine bone powder was the starting material for synthesize of nanoparticle HA via precipitation. As-precipitated HA nanoparticles were filtered, washed and finally calcined at 500, 700, 1000 °C. Phase analyses were performed by X-ray diffraction (XRD) and the result showed that the higher the calcined temperature, the higher the degree of crystallinity. The result of ammonia (NH3) gas adsorption indicated that as-precipitated HA with low crystallinity displayed better adsorption activity to NH3 gas than calcined HA with high crystallinity.
Investigation of Fracture Location of T22/T91 Dissimilar Welds
Authors: Petchsang Salita , Phung-On Isaratat , Terasaki Hidenori , Komizo Yu Ichi , Yamamoto Hajime
Published: August 2015

The aim of this investigation is to study the fracture location as well as mechanical properties of weldments from elevated temperature tensile test in T22/T91 dissimilar joining by GTAW process. Two configurations of welding procedures are used: ER90S-B9 and ER90S-B3. Postweld heat treatment (PWHT) is carried out at 760°C for 30 minutes. The results demonstrate that the higher tested temperature, the lower the strength of welded sample; nevertheless, the greater the ductility of welded sample, except ER90S-B9 welded samples tested at 650°C. The fracture of both configurations tested at 550°C and 750°C occurs at T22 BM and T91 HAZ, respectively. At these temperatures, the fracture surfaces mainly reveal dimple ductile mode corresponding to mechanical properties’ results. On the contrary, the failure tested at 650°C occurs at T22 HAZ (Soft zone) and T91 HAZ of ER90S-B9 and ER90S-B3 welded samples, respectively. The mechanical properties’ results at this temperature are relatively different. The combination of brittle and dimple mode at the edge of samples is observed on the ER90S-B9 welded samples corresponding to low ductility at this temperature. Whereas samples welded by ER90S-B3 show only dimple ductile mode. The results exhibit that the fracture location could be affected by the configuration of T22/T91 dissimilar welding.
Synthesis and Characterization of Artificial Bone Material Using Calcium from a Natural Source
Authors: Chutong Poj , Poolthong Nuchthana , Tongsri Ruangdaj
Published: August 2015

Hydroxyapatite (HAp), with chemical formula of Ca10(PO4)6(OH)2,is one of the most popular biomaterials applied as a scaffold or a scaffold component in bone tissue engineering. Synthesis of this material using calcium from a natural sourcewill be a good strategy for cost reduction. Waste cockle shells containing abundance of nearly pure calcium carbonate (CaCO3) are ideal sources of calcium. In this study, the waste cockle shells were turned to CaO nanoparticles using a simple chemical route. The CaO nanoparticle was used as a starting material to react with hydrous and anhydrous calcium hydrogen phosphate (CaHPO4) with calcium-to-phosphate (Ca/P) ratios in the range of1.5-1.67 under a mechanochemical process. The synthesized products were characterized by X-ray diffraction technique and scanning electron microscope.The experimental results revealed that under the same reaction timethe reaction using the dehydrated CaHPO4yielded a mixture ofHApand residual CaHPO4whereas the reaction using hydratedCaHPO4(CaHPO4.2H2O) yieldeda mixture of HApand beta tricalcium phosphate (β-TCP). The HAp yields of the reactions using dehydrated and hydratedCaHPO4were 71% and 51 %, respectively.
Properties of Deproteinized Natural Rubber Latex/Gelatinized Starch Blended Films
Authors: Waiprib Rungtiwa , Pichayakorn Wiwat , Boonme Prapaporn , Taweepreda Wirach , Suksaeree Jirapornchai
Published: August 2015

This research aimed to study the compatibility and properties of deproteinized natural rubber latex (DNRL)/gelatinized starch blended films for use as transdermal patches. Various starches were previously gelatinized by heat treatment. Then, the DNRL/gelatinized starch blended films were prepared by simple mixing of DNRL with gelatinized starch and then drying at 50°C. The various parameters such as types (potato, sago, bean, corn, tapioca, rice and glutinous starches), amounts (5, 10, 15 and 20 part per hundred of rubber (phr)) and concentrations of gelatinized starch pastes (5, 10, 20 and 50%) were evaluated. It was found that all starch types could be blended as a homogeneous mixture with DNRL only in 5 phr. Bean starch also provided the good mixture in 10 and 15 phr. Rice and corn starches in the concentrations up to 20 phr could also be blended. Higher concentration of gelatinized starch pastes obtained the higher viscous liquids that were difficult to blend as a homogeneous mixture with DNRL, and provided inhomogeneous blended films. The dried films of all homogeneous DNRL/gelatinized starch mixtures were slightly yellowish transparent with good physical appearances. The tensile strength, swelling and erosion of these blended films increased when increasing amounts of gelatinized starch, but their elasticities were not different comparing to that of DNRL film itself. However, their strengths should be further improved by adding some plasticizers. Some drugs would be further loaded in these homogeneous film formulations for transdermal delivery.
Photocatalytic Activity and Properties of Nanotitanium Dioxide-Filled Natural Rubber in the Presence of Coupling Agents
Authors: Toh-Ae Pornsiri , Junhasavasdikul Banja , Lopattananon Natinee , Sahakaro Kannika
Published: August 2015

Titanium dioxide (TiO2) is normally added into the rubber compounds as a white pigment and inorganic filler for an improvement of thermal property. TiO2 is also known to have an outstanding photocatalytic activity. This work investigates the properties of natural rubber (NR) compounds filled with 5 phr of nanoTiO2 (n-TiO2). Since the direct incorporation of n-TiO2 into NR encounters incompatibility problem, therefore two types of coupling agent (i.e. bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) and isopropyl trioleyl titanate (ITT)) are used. The coupling agent loading is varied in a range of 0-20 wt% relative to the n-TiO2. Mooney viscosities and minimum cure torque (ML) of the compounds increase with increasing coupling agent content and the ones with ITT show higher viscosity than the mixes with TESPT. The use of TESPT leads to shorter optimum cure time and higher torque difference compared to the use of ITT. The addition of n-TiO2 results in the improved modulus, reinforcing index and tensile strength compared to the unfilled vulcanizate. The presence of both TESPT and ITT significantly reduces a photodegradation efficiency. The difference in the properties and photocatalytic activity of n-TiO2 filled NR having TESPT and ITT as coupling agent indicates their possible different level of dispersion and interactions at the interphases.
Polycarbonate Track-Etched Membranes by Nuclear Fission Reaction: Preparation and Characterization
Authors: Jetawattana Suwimol , Pichestapong Pipat , Charoen Savapong , Picha Roppon
Published: August 2015

Uniformly-sized cylindrical pores on polycarbonate thin membranes were prepared using the nuclear fission reaction (nf) and chemical etching methods. A triuranium octoxide (U3O8)-coated plate was attached to commercial polycarbonate sheets before being bombarded with thermal neutrons (flux of 8.9 × 109 n cm-2 s-1) from the thermal column of Thai Research Reactor-1/Modification-1 (TRR-1/M1) for 15 min. The paths of nuclear fission products were collimated to perpendicularly impact the membrane surface by an interlaid 5-mm-thick particle screener. The latent tracked membrane was then chemically etched with 6 N NaOH at 60°C for 60 min. The monodisperse porous membrane obtained has average pore density 1.04 x 106 pore/cm2 with average pore diameter 1.68 μm as determined by scanning electron microscope (SEM). The mechanical and physical properties such as fluid (water and air) flow rates were analyzed. The prepared membrane was demonstrated to be able to retain different sizes and types of particles.
Thermal Properties of Banana Starch Nanocrystals Prepared by Acid Hydrolysis as Reinforcing Filler
Authors: Saeng-On Jittiporn , Aht-Ong Duangdao
Published: August 2015

Banana is one of the most important tropical fruits in Thailand. It is available throughout the year, i.e., no specific growing season, resulting to the low cost. All parts of banana plant can be used, particularly its fruit has several adaptable in term of how to eat it. However, banana is ripe and perishable easily. Therefore, it is a potential resource that can be utilized and developed in order to add more value to this raw material. In this work, green banana fruits were used as a raw material for preparing a starch nanocrystal reinforcing filler in bio-nanocomposites. The green banana was extracted into banana starch by using 0.05 N sodium hydroxide solution. The composition of the obtained banana starch contained 90.61% of starch, 18.82% of amylose, 0.19% of protein, 0.11% of ash, and 0.03% of lipid. The banana starch composition exhibited low content of protein, ash, and lipid (<0.5%) indicating that the obtained banana starch was pure enough to be used. After that, starch nanocrystal (SNC) was prepared from banana starch by acid hydrolysis with 3.5 M sulfuric acid and 3.0 M hydrochloric acid at 40°C for 7 and 5 hours, repectively. The obtained banana SNC showed an increase in the degree of crystallinity from 28.03% for native banana starch to 47.13% and 40.15% for banana SNC prepared from sulfuric and hydrochloric acid hydrolysis, respectively. Furthermore, the thermal properties of banana SNC were investigated by differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) in order to assess thermal stability of banana SNC for using as reinforcing filler in bio-nanocomposite. The decomposition temperature of native banana starch and SNC was in the range of 260-315°C. The gelatinization temperature of banana SNC increased as a result of the increment of its degree of crystallinity when comparing with native starch.
Preparation of Poly(Lactic Acid) Acrylate for UV-Curable Coating Applications
Authors: Musidang Apinya , Jiratumnukul Nantana
Published: August 2015

UV-curable process is widely used for paints, inks and adhesives due to its rapid curing, low energy consumption, high efficiency and low volatile organic compounds (VOCs). The objective of this research is to prepare poly(lactic acid) (PLA) based UV-curable coating by using glycolyzed PLA. PLA was glycolyzed by ethylene glycol (EG) at 170°C for 90 minutes. The obtained glycolyzed PLA was reacted with methacrylic anhydride (MAAH) to provide PLA acrylate oligomer. The obtained PLA acrylate oligomer was used in coating formulations with various amounts of photoinitiator and cured under UV radiation. Physical properties of cured coating film were investigated such as pencil hardness, gloss and haze. The results showed that poly(lactic acid) (PLA) based UV-curable coating provided good physical properties.
Composition-Microstructure-Property Relationships in BaTiO3 with Mg Addition
Authors: Jongprateep Oratai , Khongnakhon Tunchanoke , Palomas Jednupong
Published: August 2015

Rising worldwide demands for energy encourages development of high-efficiency energy storage and capacitor components. Main requirements for dielectric materials employed in fabrication of high energy density capacitors include high dielectric constant, high dielectric breakdown strength, and low dielectric loss. Owing to its high dielectric constant and low dielectric loss [1], barium titanate is among common capacitor materials. Tailoring of dielectric properties of barium titanate can be achieved through controlled chemical composition, microstructure, and crystal structure. Synthesis and processing techniques, as well as doping of barium titanate, can be key factors to control the composition and structure, which consequently contribute to enhancement of dielectric constant in the material.