bluuebunny/crossref_metadata_2025 huggingface dataset:
Information Need and Seeking Behavior of Farmers in Laduba Community of Kwara State, Nigeria
Authors: Akande Femi Titus , Adewojo Akinade Adebowale
Published: July 2016

The chapter present the report of a study that examined information needs and seeking haviour of farmers in Laduba community, Kwara State, Nigeria. This study adopted a survey research design using simple sampling technique to select 28 respondents from the population. Structured questionnaire was designed for the collection of data. It was discovered from the findings that majority of the farmers were illiterate of the middle aged group between 31-40. The farmers plant many crops, but it is noticeable that the farmers plant cassava mostly, the area which the farmers indicated they need information most is on agriculture, it was also observed that the farmers access information from colleagues (co-farmers), friends and relatives, agricultural extension workers. The information needs of the farmers in this study on agriculture includes how to prevent diseases for their crops on the farm and after harvesting, the farmers also stated that they need information on how to seek for loan, where to get the best market to sell their farm produce and how to get the best agro-chemical for effective use. In this study it was discovered that the challenges the farmers face in acquiring information includes, the inability to read and write in English language, lack of constant electricity supply, conflict among members of various associations and lack of access to agricultural extension workers. It is recommended that the farmers should be given effective adult education, provision of information centre with necessary personnel and information media to boost information accessibility. Also the government was encouraged to negotiate with mobile telecommunication operators to subsidize services so that the farmers who form majority in the rural areas can access information and communicate easily through their mobile phones.
Barriers to Information Seeking in the Digital Libraries
Authors: Oluwaseun Ajayi Ayo
Published: July 2016

Adequate knowledge about the information needs and seeking behaviour of users is vital for developing digital library collections, services and facilities to meet their information needs effectively. Information seeking as an underlying feature in research cannot be done without an enabling environment where needed resources and services are provided. The available literature reveals that although librarians have made good progress in adapting primary values of librarianship which are to support intellectual freedom and equitable access to information, information seeking process in the Digital Libraries has, however, been found not to be without limitations. Seeking scholarly information in the Digital Libraries is limited by the availability of reliable and affordable information and communication technologies. Information seeking in the Digital Libraries has been found to be limited to those scholars who are affiliated with organisations which have the money and skills to provide access. It has been found limited to those who are literate, information literate and have a command of the major languages of commerce and scholarship (English in particular). Infrastructure, education and skills as well as content were the three spheres identified in this Chapter as preconditions that must be satisfied if broad digital scholarly information is to be sought without restrictions. Provision of effective service in the Digital Libraries as recommended in this Chapter requires sufficient understanding of the real needs of information users and making precise efforts to satisfy them. This can best be achieved through formal in–depth studies of the information needs and seeking behaviour of users. Librarians, especially those involved in bibliographic instruction should be interested in ways individuals approach the library (be it digital or physical) and the methods they use to search for needed information. Strategies intended to improve the provision of library services should be redesigned towards information skills development and information resource awareness.
The Possibility of the Literary Work Generation by Computer
Authors: Abe Akinori
Published: July 2016

Recently the importance of entertainment for senior citizens and children has been pointed out. Accordingly, it is necessary to develop robots who can write poems, compose music, paint pictures, etc. For that, for instance, an automatic poem or story generation system will be necessary. This chapter will show the possibility of literary-work (poem, story, novel etc.) generation. First, the author introduces the research field, “Language-Sense Processing Engineering (LSE)” where the affective or psychological aspects of language is focused on. The author defined “language sense (the key concept in LSE)” as affective or psychological aspects of language. One of the features can be used for literary work generation is the “intertextuality” proposed by J. Kristeva. The possibility of the automatic literary work generation will be shown by the strategy to generate waka (Japanese poem). In addition, several strategies to generate literary works will be shown to illustrate the possibility of the automatic literary work generation.
The Dilemma of Suspense
Authors: Uboldi Sara , Calabrese Stefano
Published: July 2016

The new generation Narratology shows a renewed heuristic scenario, involving an intense dialogue among Humanities, Cognitive Neuroscience and Computer Technology. The case of suspense is emblematic: the pleasure that suspense exercises on the human mind can be precisely explained by identifying the mechanisms of reward provided by neurological and imaging studies. At the same time, patterns of automatic generation of narrations highlight the profound implications of a heated debate between Narratology and Computer Technology, in order to understand the processes of reception and inference during the narrative immersion in storyworlds. At the end of their overview on of a cross-disciplinary approach to suspense analysis, the authors report a case study considered of interest, by a group of researched, called Liquid Narrative Group, of North Caroline State University.
Dimensionality Reduction Techniques for Text Mining
Authors: Akkarapatty Neethu , Muralidharan Anjaly , Raj Nisha S. , P. Vinod
Published: July 2016

Sentiment analysis is an emerging field, concerned with the analysis and understanding of human emotions from sentences. Sentiment analysis is the process used to determine the attitude/opinion/emotions expressed by a person about a specific topic based on natural language processing. Proliferation of social media such as blogs, Twitter, Facebook and Linkedin has fuelled interest in sentiment analysis. As the real time data is dynamic, the main focus of the chapter is to extract different categories of features and to analyze which category of attribute performs better. Moreover, classifying the document into positive and negative category with fewer misclassification rate is the primary investigation performed. The various approaches employed for feature selection involves TF-IDF, WET, Chi-Square and mRMR on benchmark dataset pertaining diverse domains.
A Classification Framework on Opinion Mining for Effective Recommendation Systems
Authors: Goyal Mahima , Bhatnagar Vishal
Published: July 2016

With the recent trend of expressing opinions on the social media platforms like Twitter, Blogs, Reviews etc., a large amount of data is available for the analysis in the form of opinion mining. This analysis plays pivotal role in providing recommendation for ecommerce products, services and social networks, forecasting market movements and competition among businesses, etc. The authors present a literature review about the different techniques and applications of this field. The primary techniques can be classified into Data Mining methods, Natural Language Processing (NLP) and Machine learning algorithms. A classification framework is designed to depict the three levels of opinion mining –document level, Sentence Level and Aspect Level along with the methods involved in it. A system can be recommended on the basis of content based and collaborative filtering
A Fuzzy Relational Classifier Based Image Quality Assessment Method
Authors: De Indrajit
Published: July 2016

Fuzzy classification techniques are used for image classification for quite a long time back by allowing pixels to have membership in more than one class. However, handling information at the pixel level is time consuming and there is a high chance of biased assessment of images if class labels are assigned by a single human observer. Even considering multiple observers' opinions don't able to reflect an individual's perception in assessing quality of images, if it is crisp. In this chapter, the fuzzy relational classifier (FRC) is used to assess quality of images distorted by information loss or noise, unlike the earlier methods where images are preprocessed to remove the noise before classification.
Detection of Gradual Transition in Videos
Authors: Bhaumik Hrishikesh , Chakraborty Manideepa , Bhattacharyya Siddhartha , Chakraborty Susanta
Published: July 2016

During video editing, the shots composing the video are coalesced together by different types of transition effects. These editing effects are classified into abrupt and gradual changes, based on the inherent nature of these transitions. In abrupt transitions, there is an instantaneous change in the visual content of two consecutive frames. Gradual transitions are characterized by a slow and continuous change in the visual contents occurring between two shots. In this chapter, the challenges faced in this field along with an overview of the different approaches are presented. Also, a novel method for detection of dissolve transitions using a two-phased approach is enumerated. The first phase deals with detection of candidate dissolves by identifying parabolic patterns in the mean fuzzy entropy of the frames. In the second phase, an ensemble of four parameters is used to design a filter which eliminates candidates based on thresholds set for each of the four stages of filtration. The experimental results show a marked improvement over other existing methods.
Digital Watermarking
Authors: Thanki Rohit M. , Kothari Ashish M.
Published: July 2016

Nowadays, Multimedia contents such as images, videos, e-books and texts are easy to available for download through internet in worldwide. Duplication of multimedia contents is to create using different software. This type of operation some time created problem of copyright and ownership authentication. Digital watermarking techniques are one of the solutions for providing protection to multimedia contents. This chapter gives various watermarking techniques in transform domain and sparse domain for protection of multimedia contents. This chapter has demonstrated various watermarking techniques such as Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT), Singular Value Decomposition (SVD), Fast Discrete Curvelet Transform (FDCT), and CS theory based technique. All watermarking techniques can be applicable to every type of multimedia contents such as grayscale images or videos and color image or videos.
Design and Emotion
Authors: Landim Paula da Cruz
Published: July 2016

This chapter has the purpose to contribute to the scientific organization and assist in the process of building a theory related to the interrelation of design and emotion. It is intended that the issues addressed here raise discussions and lead to deepening these relations. In this sense this text presents aspects and situations surrounding the design in contemporaneity from, the cultural and economic relations, the meanings of the object and design of products in material culture, the aspects of industrialization and globalization, the senses of excitement and consumption and through the establishment of discourses concerning the design and the role of designers in contemporary.
Cognitive Processes in Fashion Design
Authors: Júnior Geraldo Coelho Lima
Published: July 2016

This chapter is concerned with the teaching and learning of modelling in fashion design courses. Following a series of observations, it was found that fashion design students, with normal sight, have difficulties in fully understanding how an item of clothing can be transposed to a modelling display bust, which represents the body of the wearer. The same obstacle affects visually-handicapped students. This study seeks to explore ways of overcoming this problem. It involves seeking to introduce features into teaching that can allow a comprehensive learning program to be taught and in particular, to concentrate on certain key factors - cognition, constancy and abstraction - with regard to the information on fashion projects that can be found in the surrounding learning environment.
A Survey on Strategies, Trends, Economics, and Prospects of Cloud-Based Gaming
Authors: Moses J. Sharon , L. D. Dhinesh Babu , M. Nirmala , Babu M. Rajasekhara , Krishna P. Venkata
Published: July 2016

Cloud gaming-as-a-service is emerging as one of the potential revenue generating futuristic fields with a higher growth rate. Cloud gaming service is an entertainment service that depends totally on the cloud computing technology. Cloud gaming delivers games to the gamers, anywhere at any time without any gaming specific hardware and without diminishing the gamer's quality of experience. From getting the user command to rendering the graphics, everything is processed at the gaming service provider end. The only need for the gamer is to use a thin client like web browser to access the cloud game server. In this chapter, we have detailed about the cloud game systems, cloud game services, issues in cloud gaming, economics of cloud gaming, research prospects and the evolution of cloud gaming service.
Multifunctional Dendrimers for Drug Nanocarriers
Authors: Zhang Tingbin , Zhang Chunqiu , Xing Jinfeng , Xu Jing , Li Chan , Wang Paul C. , Liang Xing-Jie
Published: July 2016

Dendrimers are nanosized, monodisperse, highly branched polymers with well-defined topological structure which have attracted much attention for drug delivery recently. To further improve the performance of dendrimers in drug delivery, various functional dendrimers are developed by decorating the dendrimers with targeting agents, imaging agents, or stimuli-sensitive moieties. They show good biocompatibility, visibility, tumor targeting and stimuli-sensitive properties for drug or gene delivery. This chapter will focus on the design of multifunctional nanocarriers based on the dendrimers. Therefore, the chapter will provide the ideas for designing the dendrimers based nanocarriers for controllable drug delivery and let more people know the development of dendrimers for drug delivery in recent years.
Li Diffusion in Lithium Containing Metal Oxides Investigated by Tracer Methods
Authors: Schmidt Harald
Published: July 2016

This article presents a review on Li diffusion in lithium containing metal oxide compounds. The focus is on the investigation of solid state diffusion by tracer methods. In contrast to experiments with Nuclear Magnetic Resonance Spectroscopy and Impedance Spectroscopy, only a limited number of tracer based experiments can be found in the literature. Possible reasons are discussed. Measurements on the system Li-Nb-O are given in detail, while additional results on other Li-M-O (M = Al, Si, Mn, Ti) systems are also presented. The review is completed by a brief survey of the experimental methods in use.
Preparation and Characterization of SrFe12O19 on Optical and Dielectric Properties of Na2O-CaO-P2O5 Glasses
Authors: Intawin Pratthana , Leenakul Wilaiwan
Published: July 2016

In this research, the effects of SrFe12O19: SF on optical and dielectric properties of Na2O-CaO-P2O5 glasses were investigated. From the study, the optically transparent glass, SF/Na2O-CaO-P2O5, system was successfully prepared by melt-quench method. The composition of SF/Na2O-CaO-P2O5 used in this study are ranging between 5-20 wt.% SF. It was found that the addition of SF enhanced the conductivity, but in turn reduced the percentage of transmittance in the glasses. The glasses subjected to be adding SF contents at higher than 15 wt% were opaque, while the lower range gave highly transparent glass ceramics. The dielectric constant (ɛr) of the SF/Na2O-CaO-P2O5 glasses were improved by increasing the content of SF, which in turn plays an important role in controlling the properties of the glass ceramics, including physical, optical, and dielectric properties.
Phase Change Properties of Chalcogenide Glasses - Some Interesting Observations
Authors: Ramesh K. , Pumlianmunga  , Venkatesh R. , Naresh N. , Gopal E.S.R.
Published: July 2016

Chalcogenide glasses switches from a high-resistance (OFF) state to a low-resistance (ON) state at a threshold voltage (Vth) under high electric fields. This electrical switching is of two types: (i) Threshold switching and (i) memory switching. Threshold switching device revert back to the OFF state immediately upon the removal of the applied voltage, whereas a memory device retains the ON state even after the removal of the applied voltage. Due to Joule heating, a filament is formed between the electrodes and the current is confined within this filament and there is an increase in current density. This increases the temperature inside the filament and there is a transition from high resistive amorphous/glass phase to a low resistive crystalline phase in memory switching materials. In the threshold switching glasses electronic processes like space charge, Poole-Frenkel effect, etc., are responsible. The structural transitions are irreversible whereas the electronic processes are reversible and hence the threshold glasses regain their original state (OFF) and memory glasses remain in the ON state.Interestingly, differential scanning calorimetric studies (DSC) show that both the threshold and memory switching glasses exhibit crystallization (structural transition). Accordingly, glasses which crystallize upon heating should exhibit memory switching behaviour. But the switching experiments indicate that among the glasses which undergo structural transition (crystallization) some show threshold switching and some show memory switching. To understand this, Cu-As-Se, Al-As-Te, Ge-As-Se-Te, Al-As-Se-Te glasses were thermally crystallized under vacuum in two ways: (i) by annealing at their respective crystallization temperatures (Tc) and (ii) heated up to their melting temperatures (Tm) and cooled back to room temperature. Interestingly, most of the threshold switching glasses shows amorphous nature or a huge amorphous background with crystalline peaks when cooled from their melting temperatures. The memory switching glasses crystallize in both the cases.We propose that both threshold and memory glasses undergo phase change and the crystalline phases formed from the melt state are responsible for switching to occur. Hence, at the time of switching the sample in between the electrodes undergo phase change by glass → melt → crystal transformation and not by the direct glass → crystal transformation.
Shift of Glass Transition Temperature under High Pressure for Ge20Te80 Glass
Authors: Ramesh K. , Naresh N. , Pumlianmunga  , Gopal E.S.R.
Published: July 2016

Amorphous solids prepared from their melt state exhibit glass transition phenomena upon heating. Derivatives of volume like viscosity, specific heat and thermal expansion coefficient show rapid changes at the glass transition temperature (Tg). In general, application f high pressure increases the Tg (a positive dTg/dP). This positive dTg/dP has been well understood with the Free Volume and Entropy models. However, there are few exceptions where a negative dTg/dP has been observed. It has been proposed that the glasses which undergo negative thermal expansion can exhibit a negative dTg/dP. In this study, electrical resistivity of semiconducting Ge20Te80 glass at high pressures as a function of temperature has been measured in a Bridgman anvil apparatus. Electrical resistivity showed a pronounced change at Tg. The pressure dependence of Tg (dTg/dP) shows a decreasing trend (-dTg/dP). Chalcogenide glasses like Se, As2Se3 and As30Se30Te40 show a positive dTg/dP in contradiction to the present observation of negative dTg/dP. A model proposed by deNeufville and Rockstad finds a linear relationship between Tg and the optical band gap (Eg) when they are grouped according to their connectivity (Zav).Application of high pressure decreases the interatomic distance which in turn decreases the separation between the valence and conduction bands (optical band gap). This reduction in optical band gap shifts the glass transition to lower values. It is also suggested that the sign of the pressure derivative of Tg can be negative (-dTg/dP) if the thermal expansion coefficient is negative. Inelastic neutron diffraction studies show a negative thermal expansion coefficient for most of the Te based chalcogenide glasses. Hence, Ge20Te80 glass is uniquethat its pressure dependence of Tgobeys both thermodynamic and the Tg-Eg-Zav models.
Investigation of Optical Properties in Sn, Sb, Pb and Bi Doped Silica Glasses Aiming Visible Fiber Laser
Authors: Sekiya Edson Haruhico , Saito Kazuya
Published: July 2016

Emission spectra of Sn, Sb, Pb and Bi doped silica glasses co-doped with Al and P prepared by modified chemical vapor-phase deposition (MCVD) using solution doping technique are presented. Bi doped silica glasses present emission/excitation (Em/Ex) bands around 470/(330, 220nm) 600/(470, 350, 270nm), 730 and 830/(820, 420, 380, 250nm), with the intensity ratio of these bands depends on the composition, indicating that different emission sources (valence states or defects) are present together. The Em/Ex of Sb doped silica glasses also depend on composition, and are similar of Bi doped silica glasses. The lifetime at 830 and 1400 in Bi or Sb doped silica glasses are similar and around 60 and 850μs, respectively. The lifetime around 600nm was 3.2 and 11μs, respectively to Bi and Sb doped silica glasses. The Sn doped silica glass present Em/Ex bands around 305/265nm, 400/(270, 340nm) and 430/280nm. The Pb doped silica glass present Em/Ex around 370/290nm and 540/320nm. No significant change in the emission bands in the visible range are observed when the Sn or Pb doped silica glass are co-doped with Al or P. The present results of Em/Ex suggest that Bi and Sb can be candidate for fiber lasing in visible range (around 600nm) using the available LD pumping (ex: 405nm). Despite Sn and Pb doping shows strong emission around 400nm, unfortunately until now there is no LD that can be used as pumping source.
Children as theological hermeneutic: Is there a new epistemological break emerging?
Authors: Botha Nico
Published: July 2016

Children are the great omission in theology. The objective of the article is to show that there is a growing realisation of this reality. More than that, there are attempts afoot to salvage the situation by factoring children more and more into theological writing, not in an objectified manner, but as serious agents of theology and, in the case of this article, as agents of mission. A few examples to this effect are shown in the article. The main thrust of the study, however, is to raise the hypothetical question of whether children have not become an important and indispensable theological hermeneutic themselves. The serious question is raised of whether children if, taken seriously in church and theology are not forcing a new epistemological break or a new way of believing and of theologising on the world of mission. A somewhat tentative and hypothetical conclusion is arrived at, which suggests that indeed there is a new rupture occurring in terms of how we know what we know in church and theology.
Hou Christus die Nederduitsch Hervormde Kerk van Afrika in stand?
Authors: Ungerer André
Published: July 2016

Does Christ sustain the Netherdutch Reformed Church of Africa? The Netherdutch Reformed Church of Africa (NRCA) that is situated in South-Africa is currently experiencing a serious decline in numbers. The question arises whether Christ will sustain the NRCA in the words of the Afrikaans Hymn 477 in the ‘Liedboek van die Kerk’ (Hymnbook of the Church): ‘Christ will maintain his church …’ Is it a matter of faith, or even more – a matter of obedience? The membership of the NRCA mainly consists of white Afrikaans-speaking people. Apart from the situation in the NRCA there is also a serious decline in the number of white people in South Africa. It raises the question about the sustainability of the NRCA if it continues to maintain a membership of predominately white Afrikaans-speaking people. The NRCA is very much institutionalised with a history that lacks missional intention and involvement in the community. This study investigates the possibility for a more applicable missional curriculum in the training of theology students to counter the lack of missional involvement. It also investigates new ways to reach the unchurched society with a missional approach. The Fresh Expression Movement that originated in the UK provides a new paradigm for the NRCA that will hopefully lead to a new way of thinking and doing. Will Christ sustain the NRCA? The answer lies in the willingness of the NRCA to show a missional heart for all the people of Africa, especially those in Southern Africa.Keywords: Missional; missional curriculum; missional ecclesiology; institutionalism; toxic organization; spiritual; church planting; fringes; Fresh Expressions
Calling, is there anything special about it?
Authors: Nel Malan , Scholtz Eric
Published: July 2016

Within the Reformed tradition, ‘calling’ is a core concept. Often, this biblical verse is cited when a pastor is installed or a new candidate is ordained, ‘The one who calls you is faithful and he will do it’ (1 Th 5:24 NIV). It is also confessed within this tradition that all Christians are called to be faithful ministers of the graces of God in whatever profession they may serve. In some Presbyterian congregations, it is a practice to say at the baptism of a child, ‘This is your ordination to ministry’. This article focuses on what is meant by calling when we use it in so many ways and with so many meanings. The first part explores the use of the concept in church history by different scholars and leaders – like in the Reformation. The second part briefly explores the implications and impact of the calling of someone into full-time congregational ministry.
‘I got content with who I was’: Rural teachers’ encounters with new ways of practising literacy
Authors: Gennrich Toni
Published: July 2016

In a context where Foundation Phase literacy teachers’ personal literacy often involves operational and technicist practices rather than creative, this paper argues that it is by exposing teachers to experiences of working with different genres of text for an extended time, in different fields, that teachers are able to imagine the possibilities these genres afford. Using a Bourdieusian framework of habitus, field, capital and doxa and applying imagination to the theorisation of these concepts, I examine the effect on a group of rural teachers from Limpopo province of being removed from their classrooms, and being given the opportunity to complete a 4-year Bachelor of Education degree at the University of the Witwatersrand. This case study used reflective journals and focus groups to trace shifts in the ways these teacher-students enacted literacy and thought about teaching literacy. Findings from this study suggest that teachers of literacy can change deeply entrenched ways of thinking about and valuing literacy by reflecting on the discontinuities between old and new ways of practice and, through anticipatory reflection, to imagine possibilities of teaching and enacting literacy differently. This requires critical imagination, awareness and agency. This paper discusses, in particular, Elela’s experience with poetry and Kganya’s experience with a drama script, assessing the effect this had on their personal literacy practices and how they imagine teaching literacy in the future.
Imagination and literacy: Introduction to the special issue
Authors: Murris Karin S. , Kell Catherine
Published: July 2016

No abstract available
Reliability of the GAIN-SS, CRAFTT and PESQ screening instruments for substance use among South African adolescents
Authors: Carney Tara , Myers Bronwyn , Louw Johann
Published: July 2016

Introduction: Screening for adolescent substance use can assist with the early identification of substance-related problems and guide the provision of appropriate services. As such, psychometrically sound screening tools are needed. The aim of this study was to compare the reliability of the CRAFFT, Global Appraisal of Individual Needs-Short Screener (GAIN-SS) substance use subscale and Personal Experience Screening Questionnaire (PESQ) among adolescents from disadvantaged communities in Cape Town, South Africa. Methods: Adolescents aged 12–19 years (n = 231) completed the three screeners at two points in time.

Results: Findings show that all three of the screeners had adequate internal consistency (Cronbach α ≥ 0.8). Test-retest reliability was similar for all three screeners, with intraclass correlation coefficient values slightly higher for the PESQ (0.82, 95% CI: 0.77–0.86) than for the GAIN-SS substance use subscale (0.79, 95% CI: 0.73–0.84) and CRAFFT (0.76; 95% CI: 0.66– 0.83). Kappa values indicated that the GAIN-SS substance use subscale and CRAFFT had moderate levels of agreement, while the PESQ had substantial levels of agreement for identifying those who had moderate or higher substance use risks at Time 1 and Time 2.

Conclusion: The findings indicate that all of these short screeners seem to have acceptable reliability when used in this population. All of the three screeners are appropriately reliable when used with adolescents from disadvantaged communities in Cape Town, but the PESQ performed slightly better. Future studies should also include the assessment of validity of these screeners in this context.
Deproteinization of tooth enamel surfaces to prevent white spot lesions and bracket bond failure: A revolution in orthodontic bonding
Authors: Justus Roberto
Published: July 2016

Orthodontic treatment success is jeopardized by the risk of development of white spot lesions (WSLs) around orthodontic brackets. Unfortunately, the formation of WSLs still remains a common complication during treatment in patients with poor oral hygiene. Nearly 75% of orthodontic patients are reported to develop enamel decalcification because of prolonged plaque retention around brackets. It is the orthodontist’s responsibility to minimize the risk of patients having enamel decalcifications as a consequence of orthodontic treatment. This can be achieved by using hybrid, fluoride-releasing, glass ionomer cement to bond brackets, with deproteinization of the enamel surface before phosphoric acid etching.
Characterizations and Representations of Core and Dual Core Inverses
Authors: Chen Jianlong , Zhu Huihui , Patricio Pedro , Zhang Yulin
Published: July 2016

In this paper, double commutativity and the reverse order law for the core inverse are considered. Then new characterizations of the Moore–Penrose inverse of a regular element are given by one-sided invertibilities in a ring. Furthermore, the characterizations and representations of the core and dual core inverses of a regular element are considered.
Local Collocation Approach for Solving Turbulent Combined Forced and Natural Convection Problems
Authors: Vertnik Robert , Šarler Božidar
Published: July 2016

An application of the meshless Local Radial Basis Function Collocation Method (LRBFCM) in solution of incompressible turbulent combined forced and natural convection is for the first time explored in the present paper. The turbulent flow equations are described by the low-Re number к – ε model with Launder and Sharma and Abe et al. closure coefficients. The involved temperature, velocity, pressure, turbulent kinetic energy and dissipation fields are represented on overlapping 5-noded sub-domains through the collocation by using multiquadrics Radial Basis Functions (RBF). The involved first and second order partial derivatives of the fields are calculated from the respective derivatives of the RBF’s. The involved equations are solved through the explicit time stepping. The pressure-velocity coupling is based on Chorin’s fractional step method. The adaptive upwinding technique, proposed by Lin and Atluri , is used because of the convection dominated situation. The solution procedure is represented for a 2D upward channel flow with differentially heated walls. The results have been assessed by achieving a reasonable agreement with the direct numerical simulation of Kasagi and Nishimura for Reynolds number 4494, based on the channel width, and Grash of number 9.6×105. The advantages of the represented mesh-free approach are its simplicity, accuracy, similar coding in 2D and 3D, and straightforward applicability in non-uniform node arrangements.
Comparisons of Heat Transfer Enhancement of an Internal Blade Tip with Metal or Insulating Pins
Authors: Xie Gongnan , Sundén Bengt
Published: July 2016

Cooling methods are needed for turbine blade tips to ensure a long durability and safe operation. A common way to cool a tip is to use serpentine passages with 180-deg turn under the blade tip-cap taking advantage of the three-dimensional turning effect and impingement like flow. Improved internal convective cooling is therefore required to increase the blade tip lifetime. In the present study, augmented heat transfer of an internal blade tip with pin-fin arrays has been investigated numerically using a conjugate heat transfer method. The computational domain includes the fluid region and the solid pins as well as the tip regions. Turbulent convective heat transfer between the fluid and pins, and heat conduction within pins and tip are simultaneously computed. The main objective of the present study is to observe the effect of the pin material on heat transfer enhancement of the pin-finned tips. It is found that due to the combination of turning, impingement and pin-fin crossflow, the heat transfer coefficient of a pin-finned tip is a factor of 2.9 higher than that of a smooth tip at the cost of an increased pressure drop by less than 10%. The usage of metal pins can reduce the tip temperature effectively and thereby remove the heat load from the tip. Also, it is found that the tip heat transfer is enhanced even by using insulating pins having low thermal conductivity at low Reynolds numbers. The comparisons of overall performances are also included.
Thermal Radiation Modelling in Tunnel Fires
Authors: Ciambelli Paolo , Grazia Meo Maria , Russo Paola , Vaccaro Salvatore
Published: July 2016

Modelling based on Computational Fluid Dynamics (CFD) is by now effectively used in fire research and hazard analysis. Depending on the scenario, radiative heat transfer can play a very important role in enclosure combustion events such as tunnel fires. In this work, the importance of radiation and the effect of the use of different approaches to account for it were assessed. Firstly, small-scale tunnel fire simulations were performed and the results compared with experimental data, then realistic full-scale scenarios were simulated. The results show up the capability of CFD modelling to reproduce with good approximation tunnel fires. Radiation proved to be noteworthy mainly when the scale of the fire is relatively large. Among the various approaches employed to simulate radiation, the use of the Discrete Transfer model gave the most accurate results, mainly when the absorption-emission characteristics of the combustion products were taken into account. Finally, the suitability of the use of CFD in quantitative Fire Hazard Analysis is discussed.
The Lower Bounds of Eigenvalues by the Wilson Element in Any Dimension
Authors: Li Youai
Published: July 2016

In this paper, we analyze the Wilson element method of the eigenvalue problem in arbitrary dimensions by combining a new technique recently developed in [10] and the a posteriori error result. We prove that the discrete eigenvalues are smaller than the exact ones.
Semi-Analytical Solution for Functionally Graded Solid Circular and Annular Plates Resting on Elastic Foundations Subjected to Axisymmetric Transverse Loading
Authors: Behravan Rad A.
Published: July 2016

In this paper, the static analysis of functionally graded (FG) circular plates resting on linear elastic foundation with various edge conditions is carried out by using a semi-analytical approach. The governing differential equations are derived based on the three dimensional theory of elasticity and assuming that the mechanical properties of the material vary exponentially along the thickness direction and Poisson’s ratio remains constant. The solution is obtained by employing the state space method (SSM) to express exactly the plate behavior along the graded direction and the one dimensional differential quadrature method (DQM) to approximate the radial variations of the parameters. The effects of different parameters (e.g., material property gradient index, elastic foundation coefficients, the surfaces conditions (hard or soft surface of the plate on foundation), plate geometric parameters and edges condition) on the deformation and stress distributions of the FG circular plates are investigated.
Mathematical Simulation of Cloaking Metamaterial Structures
Authors: Li Jichun , Huang Yunqing
Published: July 2016

In this paper we present a rigorous derivation of the material parameters for both the cylinder and rectangle cloaking structures. Numerical results using these material parameters are presented to demonstrate the cloaking effect.
A Two-Level Preconditioned Conjugate-Gradient Method in Distorted and Structured Grids
Authors: He Qiaolin
Published: July 2016

In this paper, we propose a new two-level preconditioned C-G method which uses the quadratic smoothing and the linear correction in distorted but topo-logically structured grid. The CPU time of this method is less than that of the multigrid preconditioned C-G method (MGCG) using the quadratic element, but their accuracy is almost the same. Numerical experiments and eigenvalue analysis are given and the results show that the proposed two-level preconditioned method is efficient.
A Constitutive Model for the Creep Behavior of Offwhite Marbles
Authors: Song X. D. , Ren J. H.
Published: July 2016

This paper reports an improved constitutive model for the shear creep behavior of offwhite marbles which are selected from slope and underground cavern and contain green schist’s weak structural planes. The shear creep behavior of the samples is characterized using the rheological tests. Based on the experimental measurements on mechanical properties under different normal stress conditions, an improved model is proposed to analyze the experimental results. It is demonstrated from a further discussion that such model can reflect the non-linear creep characteristics of structural planes, and especially, it is suitable for description of the viscoelastic and viscoplastic deformation behavior of structural planes.
An Iterative Two-Grid Method of A Finite Element PML Approximation for the Two Dimensional Maxwell Problem
Authors: Liu Chunmei , Shu Shi , Huang Yunqing , Zhong Liuqiang , Wang Junxian
Published: July 2016

In this paper, we propose an iterative two-grid method for the edge finite element discretizations (a saddle-point system) of Perfectly Matched Layer(PML) equations to the Maxwell scattering problem in two dimensions. Firstly, we use a fine space to solve a discrete saddle-point system of H(grad) variational problems, denoted by auxiliary system 1. Secondly, we use a coarse space to solve the original saddle-point system. Then, we use a fine space again to solve a discrete H(curl)-elliptic variational problems, denoted by auxiliary system 2. Furthermore, we develop a regularization diagonal block preconditioner for auxiliary system 1 and use H-X preconditioner for auxiliary system 2. Hence we essentially transform the original problem in a fine space to a corresponding (but much smaller) problem on a coarse space, due to the fact that the above two preconditioners are efficient and stable. Compared with some existing iterative methods for solving saddle-point systems, such as PMinres, numerical experiments show the competitive performance of our iterative two-grid method.
Application of Homotopy Analysis Method for Solving Systems of Volterra Integral Equations
Authors: Matinfar M. , Saeidy M. , Vahidi J.
Published: July 2016

In this paper, we prove the convergence of homotopy analysis method (HAM). We also apply the homotopy analysis method to obtain approximate analytical solutions of systems of the second kind Volterra integral equations. The HAM solutions contain an auxiliary parameter which provides a convenient way of controlling the convergence region of series solutions. It is shown that the solutions obtained by the homotopy-perturbation method (HPM) are only special cases of the HAM solutions. Several examples are given to illustrate the efficiency and implementation of the method.
Simulation of Incompressible Viscous Flows by Local DFD-Immersed Boundary Method
Authors: Wu Y. L. , Shu C. , Ding H.
Published: July 2016

A local domain-free discretization-immersed boundary method (DFD-IBM) is presented in this paper to solve incompressible Navier-Stokes equations in the primitive variable form. Like the conventional immersed boundary method (IBM), the local DFD-IBM solves the governing equations in the whole domain including exterior and interior of the immersed object. The effect of immersed boundary to the surrounding fluids is through the evaluation of velocity at interior and exterior dependent points. To be specific, the velocity at interior dependent points is computed by approximate forms of solution and the velocity at exterior dependent points is set to the wall velocity. As compared to the conventional IBM, the present approach accurately implements the non-slip boundary condition. As a result, there is no flow penetration, which is often appeared in the conventional IBM results. The present approach is validated by its application to simulate incompressible viscous flows around a circular cylinder. The obtained numerical results agree very well with the data in the literature.
Mathematical Simulation of Metamaterial Solar Cells
Authors: Li Jichun , Chen Yitung , Liu Yang
Published: July 2016

In this paper, we propose several solar cell designs based on metamaterials. Extensive numerical simulations of various designs with different materials are carried out. Our tests show that metamaterial solar cells are quite efficient, and over 80% and 90% absorption rates can be attained for solar spectrum and visible rays, respectively.
A Priori Error Estimates of Finite Element Methods for Linear Parabolic Integro-Differential Optimal Control Problems
Authors: Shen Wanfang , Ge Liang , Yang Danping , Liu Wenbin
Published: July 2016

In this paper, we study the mathematical formulation for an optimal control problem governed by a linear parabolic integro-differential equation and present the optimality conditions. We then set up its weak formulation and the finite element approximation scheme. Based on these we derive the a priori error estimates for its finite element approximation both in H1 and L2 norms. Furthermore some numerical tests are presented to verify the theoretical results.
A Stochastic Collocation Method for Delay Differential Equations with Random Input
Authors: Zhou Tao
Published: July 2016

In this work, we concern with the numerical approach for delay differential equations with random coefficients. We first show that the exact solution of the problem considered admits good regularity in the random space, provided that the given data satisfy some reasonable assumptions. A stochastic collocation method is proposed to approximate the solution in the random space, and we use the Legendre spectral collocation method to solve the resulting deterministic delay differential equations. Convergence property of the proposed method is analyzed. It is shown that the numerical method yields the familiar exponential order of convergence in both the random space and the time space. Numerical examples are given to illustrate the theoretical results.
An Efficient Numerical Solution Method for Elliptic Problems in Divergence Form
Authors: Abbas Ali
Published: July 2016

In this paper the problem − div(a(x,y)∇u) = f with Dirichlet boundary conditions on a square is solved iteratively with high accuracy for u and ∇u using a new scheme called “hermitian box-scheme”. The design of the scheme is based on a “hermitian box”, combining the approximation of the gradient by the fourth order hermitian derivative, with a conservative discrete formulation on boxes of length 2h. The iterative technique is based on the repeated solution by a fast direct method of a discrete Poisson equation on a uniform rectangular mesh. The problem is suitably scaled before iteration. The numerical results obtained show the efficiency of the numerical scheme. This work is the extension to strongly elliptic problems of the hermitian box-scheme presented by Abbas and Croisille (J. Sci. Comput., 49 (2011), pp. 239-267).
On the Generalized Thermoelasticity Problem for an Infinite Fibre-Reinforced Thick Plate under Initial Stress
Authors: Abouelregal Ahmed E. , Zenkour Ashraf M.
Published: July 2016

In this paper, the generalized thermoelasticity problem for an infinite fiber-reinforced transversely-isotropic thick plate subjected to initial stress is solved. The lower surface of the plate rests on a rigid foundation and temperature while the upper surface is thermally insulated with prescribed surface loading. The normal mode analysis is used to obtain the analytical expressions for the displacements, stresses and temperature distributions. The problem has been solved analytically using the generalized thermoelasticity theory of dual-phase-lags. Effect of phase-lags, reinforcement and initial stress on the field quantities is shown graphically. The results due to the coupled thermoelasticity theory, Lord and Shulman’s theory, and Green and Naghdi’s theory have been derived as limiting cases. The graphs illustrated that the initial stress, the reinforcement and phase-lags have great effects on the distributions of the field quantities.
Wave Interaction with an Emerged Porous Media
Authors: Magdalena I. , Pudjaprasetya S. R. , Wiryanto L. H.
Published: July 2016

In this paper, we study wave interaction with an emerged porous media. The governing equation is shallow water equations with a friction term of the linearized Dupuit-Forcheimer’s formula. From the continuity of surface and horizontal flux, we derived the wave reflection and transmission coefficient formulas. They are similar with the corresponding formulas of the submerged solid bar breakwater. We solve the equations numerically using finite volume method on a staggered grid. The numerical wave reduction in the porous media confirms the analytical wave transmission curve.
A Remark on the Courant-Friedrichs-Lewy Condition in Finite Difference Approach to PDE’s
Authors: Abe Kosuke , Higashimori Nobuyuki , Kubo Masayoshi , Fujiwara Hiroshi , Iso Yuusuke
Published: July 2016

The Courant-Friedrichs-Lewy condition (The CFL condition) is appeared in the analysis of the finite difference method applied to linear hyperbolic partial differential equations. We give a remark on the CFL condition from a view point of stability, and we give some numerical experiments which show instability of numerical solutions even under the CFL condition. We give a mathematical model for rounding errors in order to explain the instability.