bluuebunny/crossref_metadata_2025 huggingface dataset:
Composite Coatings Employing a Novel Hybrid Powder and Solution-Based Plasma Spray Technique for Tribological Applications
Authors: Sivakumar G. , Joshi S. V.
Published: May 2015

Solution Precursor Plasma Spray (SPPS) technique is an emergent technique which offers significant performance advantages with various functional coatings like YSZ, ZnFe2O4, LSM, metal-doped ZnO, etc. Apart from the above capabilities, efforts towards development of an innovative hybrid approach through simultaneous deposition of powder and solution resulted in coatings with unique microstructures. Some illustrative examples of the large variety of coatings that can be realized through the hybrid route combining the conventional plasma spray and SPPS techniques are discussed. The attractive prospects offered by hybrid technique for spraying nanocomposite coatings are specifically highlighted through a case study. Successful development of hybrid coatings using a Mo-alloy powder and a suitable oxide-forming solution precursor has been shown to exhibit improved sliding wear performance. The relationship between the splats, the ensuing coating microstructure at varied processing conditions, and its tribological behaviour of the coatings is comprehensively discussed.
Solid Particle Erosion of Thermal Sprayed Coatings
Authors: Sapate S. G. , Roy Manish
Published: May 2015

Solid particle erosion is an important material degradation mechanism. Although various methods of coating are tried and used for protection against erosion, thermal sprayed coating for such purpose is the most widely used method. In this chapter, evolution of thermal sprayed coating, erosion testing methods, and erosive wear of thermal sprayed coatings are discussed extensively with emphasis on recent developments. It is generally found that erosion of thermal sprayed coatings depends on erosion test conditions, microstructural features, and mechanical properties of the coating materials. Most thermal sprayed coatings respond in brittle manner having maximum erosion rate at oblique impact and velocity exponent in excess of 3.0. Erosion rate is also dependent on thermal spraying techniques and post coating treatment. However, little work is done on dependence of erosion rate on coating techniques and coating conditions. Future direction of work is also reported.
Detonation Sprayed Coatings and their Tribological Performances
Authors: Rao D. Srinivasa , Sivakumar G. , Sen D. , Joshi S.V.
Published: May 2015

The Detonation Spray Coating (DSC) process is a unique variant among the wide choice of thermal spray processes. The typical functionalities of DSC coatings include wear and corrosion resistance, elevated temperature oxidation resistance, thermal barrier, insulative/conductive, abradable, lubricious surface, etc. Among the coatings for wear resistance, the cermet coatings based on WC–Co and Cr3C2–NiCr are the most popular materials of choice and contribute to bulk of the utilization by the industry towards wear resistance. Notwithstanding the above materials, alternative materials involving modifications in both hard and binder phases like TiMo (CN)–NiCo, WC-CrC-Ni, WC-Co-Cr, WC-Ni, Cr3C2-Ni, Cr3C2-Inconel, etc. exhibit great promise towards tribological applications under diverse wear modes. This chapter on the tribological characteristics of the detonation sprayed coatings provides a comprehensive overview on the characteristics of various cermet coatings generated at varied process conditions and its influence on the tribological properties under abrasive, sliding, and erosive wear modes.
Characterization of Mechanical Properties and the Abrasive Wear of Thermal Spray Coatings
Authors: Barbhuiya Salim , Choudhury Ikbal
Published: May 2015

Thermal spray is a generic term used to define a group of coating processes used to apply both metallic and non-metallic coatings. These coatings are usually defined by their hardness, strength, porosity, roughness, and wear resistance. In this chapter, the authors turn their attention to the mechanical and tribological properties of thermal spray coatings. The individual phase plays a very important role in determining the performance of the coating. However, evaluating the mechanical and tribological properties at a nano-level requires new test methods and their validation. In this chapter, elaborate discussion of some techniques to evaluate and analyze the mechanical and tribological properties of different thermal spray coatings is done. This chapter is intended to help the reader to firstly understand the basic principle and methods of characterization of thermal spray coatings using instrumented nanoindentation, nanoscratch, abrasive wear testing techniques, and secondly to get an idea of the recent techniques and review the research and development in the same field.
Assessing the Profitability of Changing a Turbine for a Hydroelectric Power Plant Based on Long-Period Water Gauge Readings
Authors: Wiśniewski Jan H. , Olszański Bartosz M.
Published: May 2015

The chapter focuses on explaining the construction of author's own engineering-level model which calculates energy production based on historical water level and flow rate readings as well as economic factors such as net present value of the proposed investment on the example of a HPP on the Wkra River. The model methodology assumes the identification of location's hydrological features and translates them into a set of contingency scenarios. Various internal costs, such as maintenance or labor costs, related to normal HPP activity and taxation are discussed and incorporated into the economic part of the model. Test case results indicate that for a series of good years in terms of water flow and electricity production, full repayment of initial investment costs is possible after less than three years. Results for the chosen modernization parameters indicate that within 10 years of installing a new turbine, even the most pessimistic case would bring added value to the real estate valuation.
An Overview to Thermal Solar Systems for Low Temperature
Authors: González-Prida Vicente , Raman Anthony
Published: May 2015

This chapter deals with those prefabricated systems with a steady state of operation (state in which the temporal variation of the thermodynamic properties is null), describing, in a brief manner, a methodology for testing the characterization of the thermal performance in accordance with the European normative. All of the previously mentioned form the justification for a foundation or base from which a testing installation is proposed in a later chapter that, at the same time, is compared to a real installation. Lastly, this chapter attempts to outline a simple mathematical methodology to analyze the future behavior of the reliability of a system (solar in this case), when it is still in an extremely early stage of its life cycle, such as the design phase.
The Topicality and the Peculiarities of the Renewable Energy Sources Integration into the Ukrainian Power Grids and the Heating System
Authors: Shendryk Vira , Shulyma Olha , Parfenenko Yuliia
Published: May 2015

The chapter proposes to approach the problem in the following ways: assess the problems in the existing power system, analyze the current state of the RES using, and determine the existing ways of computer modeling of the grid. The chapter also discusses the topicality of renewable energy use in the construction of distribution grids and the ability to model their work. It explores issues including current research attempts to identify the existing methods, which can be applied in the Decision Support System (DSS) for calculation and evaluation RES. The problem of making decisions for energy saving in district heating requires such measures as energy audit and planning. These activities require monitoring the current energy consumption in real time.
Clean Technology Industry
Authors: Tonisson Liina , Maicher Lutz
Published: May 2015

Many clean technology transfer barriers have been associated to Intellectual Property (IP) rights. The objective of this chapter is to give insights to the types of IP rights services the clean technology industry needs to overcome. By conducting in-depth qualitative interviews with a convenience sample of 25 clean technology companies in 2012, most outsourced intellectual property-related services were discovered. The clean technology companies specified the following top three IP services required from service providers: legal services for IP protection, legal services for IP transactions, and IP consultancy (i.e. IP portfolio analyses). The companies investigated outsource IP-related processes to service providers. That leads to the conclusion that outsourcing patent-related activities is an efficient management decision for the clean technology industry. Outsourcing tasks to competent service providers who are familiar with foreign technology and legal markets were found to be especially useful against infringement threats from developing countries.
Enhanced Student Engagement through Active Learning and Emerging Technologies
Authors: Cardullo Victoria M. , Wilson Nance S. , Zygouris-Coe Vassiliki I.
Published: May 2015

Active learning and emerging technologies are enhancing student learning though an explicit intentional educational design such as Flipping the Classroom and Project Based Learning to empower students. In this chapter, the authors describe an active learning classroom and emerging technologies that support learning for the 21st century. Using vignettes, the authors model how the metacognitive teacher supports the use of emerging technologies for active learning using the Metacognitive Technological Pedagogical Content Knowledge Framework (M-TPACK) (Wilson, Zygouris-Coe, Cardullo, & Fong, 2013). Finally, the authors describe Blooms Taxonomy (Bloom et al., 1956) for active learning and make connections to emerging technologies and the level of integration using the SAMR Model: Substitution, Augmentation, Modification, and Redefinition (Puentedura, 2006).
Educational Robotics as a Learning Tool for Promoting Rich Environments for Active Learning (REALs)
Authors: Eguchi Amy
Published: May 2015

In our ever-changing society where new technological tools are being introduced into daily life more rapidly than ever before, more and more innovative and creative people are needed for the work of advancing technology. However, current educational practice in schools seems to be moving away from helping to educate our future innovative and creative workforce. With the extensive focus on assessments through standardized testing, the concern is raised that more and more teachers are forced to teach to the test. In this chapter, educational robotics is introduced as a transformational tool for learning, which promotes learning of computational thinking, coding, and engineering, all increasingly being viewed as critical ingredients of STEM learning in K-12 education. The purpose of this chapter is to highlight the importance of integrating educational robotics as a technological learning tool into K-12 curriculum to promote Rich Environments for Active Learning (REALs) to prepare students for the technology-driven future.
Constructivist Internet-Blended Learning and Resiliency in Higher Education
Authors: Penland Jennifer L.
Published: May 2015

This chapter focuses on the changes that have occurred recently in the distance education arena and the impact on higher education institutions focusing on undergraduate and graduate students taking these courses. Data were gathered from 164 individual participants enrolled in education courses at Shepherd University during the spring 2013, fall 2013 and spring 2014 semesters from end of course surveys with ten questions focusing on the following areas: when students learn, why students learn and how students learn. Findings suggested; (1) increased enrollment in distance education courses, (2) courses allow for flexible schedules (3) better communication with instructor and (4) more meaningful learning overall for students.
A Call for Teacher Preparation Programs to Model Technology Integration into the Instructional Process
Authors: Estes Judi Simmons
Published: May 2015

The purpose of this chapter is to create a sense of urgency for teacher preparation programs to integrate technology into the instructional process. School administrators expect that first-year teachers will know how to integrate technology with instruction to enhance the teaching-learning process (Webb, 2011). Yet, teacher preparation program faculty, do not consistently model the use or pedagogy of technology-infused coursework. The intentional embedding of technology in teacher preparation courses and assignments is critical in developing teacher candidates with requisite technology knowledge and skills for P-12 teaching in the 21st century. This chapter discusses: (a) the need for technology literate teachers, (b) the role of teacher preparation programs, (c) the need for technology literate faculty, (d) one training model for integrating technology into instruction, enhancing Missouri's Instructional Network Teaching Strategies (e-MINTS).
A Model for Meaningful E-Learning at Canadian Universities
Authors: Carter Lorraine , Salyers Vince
Published: May 2015

There is no questioning the growth of e-learning in universities around the world. Whether or not we are doing it effectively and meaningfully is where the uncertainty lies. In this chapter, two e-learning researchers from Canada offer their perspective on e-learning in that country. This perspective includes a snapshot of the Canadian e-learning landscape as well as the results of a multi-university research study called the Meaningful E-Learning or MEL project. The authors explore four themes derived from the MEL project and represented by the acronym HIDI (human interaction, IT support, design, and institutional support) in relation to three e-learning scenarios. While each element of HIDI is recognized as important, the criticality of institutional support and design cannot be overemphasized in the pursuit of excellence in e-learning.
Active Learning Strategies in Technology Integrated K-12 Classrooms
Authors: Ntuli Esther
Published: May 2015

Active learning is central to student retention and application of learned information. Research indicates that technology has reshaped the classroom environment and some of the teaching methods that traditionally supported active learning are no longer compatible with the emerging technologies. The question is; how best can teachers promote active learning through the use of technology? With technology flooding the school learning environments, teachers need effective strategies that promote active learning. Using research-based theories and literature review; this chapter extends a new definition and critical components of active learning in the context of technology integrated classrooms. Further, the chapter offers active learning strategies aligned with technology tools that could be used effectively in K-12 classrooms to promote active learning. Finally, the chapter opens up a discussion for potential new research that could be conducted to explore in depth some of the strategies using a large sample size stratified by grade levels, content areas, and geography.
Teaching History of Mathematics through Digital Stories
Authors: Incikabi Lutfi
Published: May 2015

This chapter introduces a way for enhancing teaching history of mathematics through digital storytelling. Adapting digitals stories in the form of historical documentaries, this chapter also provides components of digital storytelling (point of view, dramatic question, emotional content, the gift of your voice, the power of the soundtrack, economy, pacing, purpose of story, choice of content, quality of images, grammar and language usage) and necessary steps (tellable story, compositing script, choosing visual and audio components, preparing digital stories, presenting digitals stories) that are to be taken into consideration while preparing digital stories.
Active Learning, Deliberate Practice, and Educational Technology in Professional Education
Authors: Han Heeyoung , Han Seung Hyun , Lim Doo Hun , Yoon Seung Won
Published: May 2015

This chapter is an interdisciplinary literature review on pedagogical approaches and technological integration processes to facilitating active learning and deliberate practice toward expertise in professional education. The review covers selective domains that emphasize life-long learning, including teacher education, professional music education, athletic education, and medical education. The authors' review finds that concepts and principles of active learning are recognized in all of them and technology is frequently implemented to facilitate the process of active learning, but systematic and system-wide processes for incorporating active learning with deliberate practice are lacking, especially at the institution or curriculum level. To fill the gap, the authors discuss how the selected instructional design or established performance improvement processes in the educational technology literature can be applied.
iPad
Authors: Thomas Ursula
Published: May 2015

It is the unavoidable and it is not going away. The gravity of technology has firmly planted itself in our daily existence and yes, this includes teacher education. As technology has because our normative environment in daily life it has also become normative in educator preparation; our new oxygen. This commonplace element is hailed as a tool of equity for learners, preschool through college. Our current populations of learners are digital natives, but many educational leaders are digital tourists. As we look to challenge the traditional notions of distance learning, program offerings, and educator preparation models we must rapidly embrace the persona of the digital native to increase relationships with those we prepare as teachers while at the same time valuing and increasing diversity and voice. This chapter seeks to examine how a teacher educator engages preservice teachers in the world of diversity using technology.
Perceptions of Competencies Developed in an Active Learning Course Featuring the Design of Web-Based Instruction on Mathematics
Authors: Tokmak Hatice Sancar , Incikabi Lutfi
Published: May 2015

This chapter presents a research study on mathematics education pre-service teachers' perceptions of competencies developed in an active learning course. During the course, the pre-service teachers designed web-based instruction (WBI) to teach mathematics to a targeted group of children. Data were collected through a demographic questionnaire, unstructured focus group interviews, open-ended questionnaires, and WBI design documents. WBI documents were analyzed according to Khan's (1997) identified components. The results of the study showed that, according to the mathematics education pre-service teachers, their internet search skills, content knowledge about distance education, web interface design skills, and technological knowledge increased or improved due to the WBI project. Moreover, participants observed how the constructivist philosophy did not apply to their designs. In addition, their designs were created from the perspectives of users rather than producers, as many components of WBI were not taken into account during or after the project.
Deployment and Adoption Strategy of Cloud Computing for Blended Learning in Higher Education Institutions in Sub-Saharan Africa
Authors: Mtebe Joel S. , Kissaka Mussa M.
Published: May 2015

Many higher education institutions in sub-Saharan Africa have been blending traditional face-to-face delivery with various Information and Communication Technologies (ICT) to meet the strong demand for higher education as well as to improve the quality of traditional campus programs. Despite the increased adoption of various forms of blended learning in the region, the cost of acquiring and managing ICT infrastructure remained to be the biggest challenge. While cloud computing can provide powerful computing at a fraction of the cost of traditional ICT infrastructure, its potential to enhance blended learning in higher education in sub-Saharan Africa is unexplored. This chapter proposes deployment and adoption strategy of cloud computing to enhance blended learning services in the region. This work contributes towards helping higher education in sub-Saharan Africa to understand cloud services and to make plans for successful migration of computing services into cloud.
Study of Co-Mn/TiO2 SCR Catalyst at Low Temperature
Authors: Hu Hua , Xie Jun Lin , Fang De , He Feng
Published: May 2015

The Co-Mn/TiO2 catalysts with different contents of Co were prepared by the impregnation method. Catalytic activity tests showed that the addition of Co could obviously enhance the SCR performance of Mn/TiO2 catalyst, and the NO conversion of 0.05Co-Mn/TiO2 samples could reach 94.03% at 180 °C. At the same time, with the help of XRD, BET, H2-TPR and NH3-TPD, the various physical and chemical characteristics as well as phase structures of catalysts were characterized systematically. According to the results, the formations of crystalline CoMn2O4, Mn3O4 and amorphous Mn2O3 were detected. Furthermore, Co doping could reduce the reduction temperatures of catalysts and enhance the adsorption capacities of NH3, resulting in the excellent SCR performance at low temperature.
Fabrication of High-Aspect-Ratio Structural Change Microregions in Silicon Carbide by Femtosecond Bessel Beams
Authors: Zhao Liang Liang , Wang Feng , Xie Jun , Zhao Wei Wei
Published: May 2015

This letter presents the morphology of femtosecond Bessel beams induced high-aspect-ratio structural change regions in bulk silicon carbide. An axion is engaged in transforming Gaussians beams to Bessel beams, which are then focused on the surface or below the surface of the sample by combination of a plano-convex lens and a microscope objective. The sample is scanned by the focused femtosecond Bessel beams at the preset patterns. Through this method, the high-aspect-ratio uniform laser induced structure change regions have been produced and the highest respect ratio can reach 206 with the depth of 330 μm, the width of 1.6 μm in optimized conditions of appropriate focusing position and pulse energy. This result is attributed to uniform energy distribution in the long propagation distance of Bessel beams with nondiffracting. This technique will have great potential applications to make high-aspect-ratio microgrooves in wide-gap and transparent materials.
Numerical Investigation of the Damage Behavior of S355 EBW by Cohesive Zone Modeling
Authors: Tu H.Y. , Weber Ulrich , Schmauder Siegfried
Published: May 2015

In this paper, the cohesive zone model is used to study the fracture behavior of an electron beam welded (EBW) steel joint. Mechanical properties of different weld regions are derived from the tensile test results of flat specimens, which are obtained from the respective weld regions. Based on the tensile test of notched round specimens, the cohesive strength T0can be fixed. With the fixed T0value, the cohesive model is applied to compact tension (C(T)) specimens with the initial crack located at different positions of weldment with different cohesive energy values Γ0. Numerical simulations are compared with the experimental results in the form of force vs. Crack Opening Displacement (COD) curves as well as fracture resistance (JR) curves.
Determining the True Strength of the Material of Fiberglass Thick Rings when Stretched with Half-Disks
Authors: Turusov Robert A. , Kuperman Alexandr M. , Andreev Vladimir I.
Published: May 2015

The article presents the results of a study of elastic-strength properties of unidirectional rings of fiberglass in tension them with half-disks at a variation in a wide range of diameter and thickness of the rings. The analysis of the results clarified the mechanisms of destruction fibreglasses and the possibility of expanding the application of the method.
Numerical Modelling of Heterodiffusion from the Variable Type Source
Authors: Pokoev A.V. , Volkov V.V.
Published: May 2015

The algorithm for numerical modeling of the heterodiffusion from a finite thickness layer under restricted impurity solubility in the matrix and concentration dependence of the diffusion coefficient is proposed. It allows obtaining the time dependence of the impurity distributions in conditions which mimic real experiments.
Ti and Ni Grain Boundary Diffusion in B2 NiTi Compound
Authors: Liu Dan Dan , Fiebig Jochen , Peterlechner Martin , Trubel Simon , Wegner Matthias , Du Yong , Jin Zhan Peng , Wilde Gerhard , Divinski Sergiy V.
Published: May 2015

The radiotracer technique was used to measure the grain boundary diffusion of 44Ti and 63Ni in slightly Ni-rich polycrystalline NiTi compound in the temperature range of 673 - 923 K. The temperature dependence of the grain boundary triple product P (P = sδDgb, s is the segregation coefficient, δ is the grain boundary width, and Dgb is the grain boundary diffusion coefficient) for Ti and Ni was determined. The triple products of both Ti and Ni grain boundary diffusion in NiTi reveal a unique behavior with significant deviations from an Arrhenius-type dependence. Probable evolution of the grain boundary structure with temperature was used to interpret this phenomenon.
Formation of Vanadium Oxide (V-O System) Graded Compounds under Strong Gravitational Field
Authors: Khandaker Jahirul Islam , Tokuda Makoto , Ogata Yudai , Nishiyama Tadao , Mashimo Tsutomo
Published: May 2015

Strong gravitational field induces sedimentation of atoms due to the different body forces acting on respective atoms, and gives a tool for controlling elemental compositions in condensed matter. Vanadium oxide (V-O system) has large contrast in phases like VO, V2O3, VO2, V2O5 etc., and shows the respective interesting diverse electrical and optical properties. We performed a strong-gravity experiment (0.397106G at 400°C for 24 hours) on a V2O5 polycrystal using the high temperature ultracentrifuge to examine the composition change and further the structure change. It was found by the XRD and Raman scattering method that VO2 and V2O3 phases appeared and the amounts were increased, while one of the V2O5 phase decreased gradually along with the increasing gravitational field.
Dislocation Mass-Transfer and Electrical Phenomena in Metals under Pulsed Laser Influence
Authors: Filatov A. , Pogorelov A. , Kropachev D. , Dmitrichenko O.
Published: May 2015

The influence of moving dislocations on mass-transfer and the phenomena, accompanying it in pulse-deformed metals is studied in a real-time. Transport of self-interstitial atoms (SIAs) by mobile edge dislocations in crystal with FCC lattice is investigated by molecular dynamics. A strain rate (106 s-1) and dislocation density (1010 – 1012 cm-2) in simulated crystal corresponds to a laser effect in a Q-factor mode. The experimental investigations in a real-time are performed by recording of electrical signal induced by the laser pulse irradiation of metal foils of different crystal structures.
Neutron Reflectometry for the Investigation of Self-Diffusion in Amorphous Silicon
Authors: Strauß Florian , Geue Thomas , Stahn Jochen , Schmidt Harald
Published: May 2015

We present experiments based on neutron reflectometry in combination with 29Si/natSi isotope multilayers in order to investigate the self-diffusion in amorphous silicon. Such experiments allow the detection of diffusion processes in the amorphous state on length scales below 10 nm. First results at 650 °C show a continuous decrease of the artificial Bragg peak produced by the multilayer, corresponding to a diffusivity of (1.1 ± 0.4) x 10-20 m2/s on a length scale of 2 - 7 nm. The diffusivity is not time-dependent for annealing times between 3 min and 1 h. Compared to recent measurements in silicon single crystals by the same method, the diffusivity is higher by a factor of about 105.
About the Formation of the Supersaturated Solid Solutions by Diffusion Process
Authors: Rodin Alexey O. , Prokoshkina D. , Itckovitch A. , Dolgopolov N.
Published: May 2015

It is generally agreed that during diffusion process between two phases e.g. matrix/diffusant layer the thermodynamic equilibrium state is fulfilled and the supersaturated solid solutions can not formed by diffusion. Nevertheless, in many cases the formation of equilibrium phases does not occur due to kinetic and other reasons, and metastable phases can be formed. The analysis of the concentration profiles for bulk diffusion obtained at low temperatures consistent with B-regime for grain boundary diffusion in systems Cu/Al, Fe and Co/Cu is performed. It is shown that in these systems the supersaturated solutions are formed and the extent of supersaturation is the more as the diffusion temperature is lower. The concentration of diffusant may be 5-10-times greater than solubility according to phase diagram.
Mn Diffusion and Reactive Diffusion in Ge: Spintronic Applications
Authors: Portavoce Alain , Abbes Omar , Bertaina Sylvain , Rudzevich Yauheni , Chow Lee , Le Thanh Vinh , Girardeaux Christophe , Michez Lisa
Published: May 2015

In this paper, we report investigations concerning the fabrication of a diluted Ge (Mn) solution using solid state Mn diffusion, and Mn/Ge reactive diffusion for spintronic applications. The study of Mn diffusion shows that the quasi-totality of the incorporated Mn atoms occupies Ge substitutional sites and probably exhibits two negative elementary charges. The solubility limit of Mn in Ge is comprised between 0.7 and 0.9 % (T  600 °C). We show that substitutional Mn atoms are not ferromagnetic in Ge and consequently that Ge (Mn) diluted magnetic semiconductor can not be produced. Beside the ferromagnetic signal from Mn5Ge3, ferromagnetic signals detected in the samples could be always attributed to surface or bulk Mn-Ge clusters. Furthermore, we show that the CMOS Salicide process is potentially applicable to Mn5Ge3 nanolayer fabrication on Ge for spintronic applications. During Mn (thin-film)/Ge reaction, Mn5Ge3 is the first phase to form, being thermally stable up to 310 °C and exhibiting ferromagnetic properties up to TC ~ 300 K.
Radiotracer Experiments and Monte Carlo Simulations of Sodium Diffusion in Alkali Feldspar: Evidence against the Vacancy Mechanism
Authors: Wilangowski F. , Abart R. , Divinski Sergiy V. , Stolwijk N.A.
Published: May 2015

Self-diffusion of sodium perpendicular to (001) in a potassium-rich alkali feldspar singlecrystal has been studied by self-diffusion experiments and by Monte Carlo simulations. Sodium diffusivitieswere measured with the radiotracer technique using the 22Na isotope in a temperature intervalfrom 773 K to 1173 K. It was found that self-diffusion coefficients follow a linear Arrhenius relationwith the pre-exponential factor of 1:2 103 cm2/s and an activation enthalpy of 1:3 eV. To study correlationeffects in the monoclinic feldspar structure, a Monte Carlo method was applied assuming thatthe two cation species are randomly distributed on the common sublattice and are not influenced by thefixed sublattice of the silicate and aluminate anions. Correlation factors have been calculated assuminga vacancy mechanism and applying a developed four-frequency model for the nearest-neighborvacancy jumps on the alkali sublattice. Our findings strongly indicate that vacancy diffusion providesonly a minor contribution to sodium self-diffusion in potassium-rich feldspars.
Cobalt Doping as the Controlling Factor of Oxygen Diffusivity in ZnO by More than Four Orders of Magnitude
Authors: Hashiguchi Minako , Sakaguchi Isao , Miyazaki Reona , Takada Kazunori , Ohashi Naoki
Published: May 2015

Oxygen diffusivity in ZnO ceramics doped with cobalt was investigated using an isotope tracer method. The oxygen isotope (18O) was introduced by 18O/16O exchange annealing in an 18O2 atmosphere, and the depth profile of the 18O concentration was analyzed by secondary ion mass spectrometry. The results show that oxygen diffusivity in ZnO steeply increases with increasing Co concentration. In fact, the bulk oxygen diffusivity in 15 mol% Co-doped ZnO was four orders of magnitude greater than that of nominally non-doped ZnO. Oxygen diffusivity at grain boundaries was also enhanced by Co-doping.
Different Aspects of Single Wall Carbon Nanotube Functionalization by Aniline Adsorption; Quantum Mechanics/Molecular Mechanics Study
Authors: Abedini Mohamood , Izadyar Mohammad , Nakhaeipour Ali
Published: May 2015

In this research, kinetics and mechanism of aniline adsorption on different single-walled carbon nanotubes (SWCNT) was investigated, using 2-layer ONIOM (Our own N-layered Integrated molecular Orbital and molecular Mechanics) method at the ONIOM (B3LYP/6-31G (d);UFF) level. Various orientations of aniline relative to the carbon nanotube surface were investigated. To investigate the adsorption of aniline, three models including open-ended (model 1), cap-ended (model 2) and 1-cap-ended (model 3) SWCNT have been modeled. Calculated activation energies of adsorption showed that model 2 has the lowest activation energy of 40.8 kcal.mol-1. Natural bond orbital and frontier molecular orbital analysis confirmed the charge transfer from the aniline to the SWCNT. Density of states analysis showed that Fermi level is shifted towards the positive values after aniline adsorption which confirmed the effective interactions between the aniline and the SWCNT. According to the quantum theory of atoms in molecules studies, new bonds formed between the SWCNT and aniline which possess a covalence nature. Finally, based on the quantum reactivity indices, new linear correlations between the chemical hardness, charge transfer and activation energy and the inverse relationship of the electrophilic property and chemical electronic potential in the functionalized carbon nanotubes were obtained. Wiberg bond index calculations show that this reaction is carried out through an asynchronous concerted mechanism. Asynchronicity value in the case of model 2 is higher than other models.
Enhanced Luminescence of L-Alanine Capped LaF3:Ce Nanoparticles Useful in Biological Labeling
Authors: Singh Amit T. , Khandepekar Mahendra M. , Khandpekar M.M. , Gaurkhede S.G.
Published: May 2015

Hexahedral nanocrystals of L-Alanine [CH3CH(NH2)COOH] doped LaF3:Ce (ALFC) of assorted sizes have been synthesized in deionized water using water soluble chlorides of lanthanides with subsequent microwave irradiation to reduce agglomeration. The average particle sizes obtained by XRD, SEM, and TEM have been 22nm, 37nm and 23nm respectively. The surface modification by functional groups of L-Alanine is observed in the FTIR and FT-RAMAN spectra and their decomposition is studied in TGA/DTA spectrum .The electron-phonon interaction of A1gphonon mode and fundamental Egphonon mode have been observed in far infra-red region by FT-RAMAN spectra. The UV-Vis spectrum shows multiple absorption edges corresponding to energies at E1= 5.11eV, E2= 4.47eV, and E3=5.781eV which indicates the quantum dot nature of the nanocrystals and its application in optoelectronic devices. ALFC nanocrystals showed green color emission peak centered at 554 nm with their potential application in bio imaging and bio tagging.Keywords: nanostructures, fluorides, Transmission electron microscopy, Raman spectroscopy, Thermogravimetric analysis (TGA).
Return to Preinjury Levels of Participation After Superior Labral Repair in Overhead Athletes: A Systematic Review
Authors: Sciascia Aaron , Myers Natalie , Kibler W. Ben , Uhl Timothy L.
Published: May 2015

Context

Athletes often preoperatively weigh the risks and benefits of electing to undergo an orthopaedic procedure to repair damaged tissue. A common concern for athletes is being able to return to their maximum levels of competition after shoulder surgery, whereas clinicians struggle with the ability to provide a consistent prognosis of successful return to participation after surgery. The variation in study details and rates of return in the existing literature have not supplied clinicians with enough evidence to give overhead athletes adequate information regarding successful return to participation when deciding to undergo shoulder surgery.

Objective

To investigate the odds of overhead athletes returning to preinjury levels of participation after arthroscopic superior labral repair.

Data Sources

The CINAHL, MEDLINE, and SPORTDiscus databases from 1972 to 2013.

Study Selection

The criteria for article selection were (1) The study was written in English. (2) The study reported surgical repair of an isolated superior labral injury or a superior labral injury with soft tissue debridement. (3) The study involved overhead athletes equal to or less than 40 years of age. (4) The study assessed return to the preinjury level of participation.

Data Extraction

We critically reviewed articles for quality and bias and calculated and compared odds ratios for return to full participation for dichotomous populations or surgical procedures.

Data Synthesis

Of 215 identified articles, 11 were retained: 5 articles about isolated superior labral repair and 6 articles about labral repair with soft tissue debridement. The quality range was 11 to 17 (42% to 70%) of a possible 24 points. Odds ratios could be generated for 8 of 11 studies. Nonbaseball, nonoverhead, and nonthrowing athletes had a 2.3 to 5.8 times greater chance of full return to participation than overhead/throwing athletes after isolated superior labral repair. Similarly, nonoverhead athletes had 1.5 to 3.5 times greater odds for full return than overhead athletes after labral repair with soft tissue debridement. In 1 study, researchers compared surgical procedures and found that overhead athletes who underwent isolated superior labral repair were 28 times more likely to return to full participation than those who underwent concurrent labral repair and soft tissue debridement (P < .05).

Conclusions

The rate of return to participation after shoulder surgery within the literature is inconsistent. Odds of returning to preinjury levels of participation after arthroscopic superior labral repair with or without soft tissue debridement are consistently lower in overhead/throwing athletes than in nonoverhead/nonthrowing athletes. The variable rates of return within each group could be due to multiple confounding variables not consistently accounted for in the articles.
Оптимальное управление для сингулярной стационарной системы с фазовым ограничением и вариация по состоянию
Authors: Serovaiskii Semen Yakovlevich
Published: May 2015

Рассматривается задача оптимального управления системой,
описываемой сингулярным нелинейным уравнением эллиптического
типа с фазовым ограничением в форме включения. С помощью
варьирования состояния системы получены необходимые условия
оптимальности.
Библиография: 15 названий.
Об аппроксимируемости относительно сопряженности некоторых свободных конструкций групп корневыми классами конечных групп
Authors: Sokolov Evgeny Viktorovich
Published: May 2015

Пусть $\mathcal{C}$ - произвольный корневой класс групп,
состоящий лишь из конечных групп и содержащий хотя бы одну
неединичную группу. Доказано, что любое расширение свободной
группы при помощи $\mathcal{C}$-группы аппроксимируется
классом $\mathcal{C}$ относительно сопряженности. Установлено
также, что если $G$ - свободное произведение двух
$\mathcal{C}$-аппроксимируемых относительно
сопряженности групп с конечной объединенной подгруппой
или HNN-расширение $\mathcal{C}$-аппроксимируемой
относительно сопряженности группы с конечными связанными
подгруппами, то $\mathcal{C}$-аппроксимируемость
группы $G$ равносильна ее $\mathcal{C}$-аппроксимируемости
относительно сопряженности.
Библиография: 14 названий.
Исследование разрешимости задачи термовязкоупругости для линейно упруго-запаздывающей жидкости Фойгта
Authors: Zvyagin Andrey Viktorovich , Orlov Vladimir Petrovich
Published: May 2015

В статье исследуется проблема существования слабого решения
для начально-краевой задачи термовязкоупругости
одной математической модели, описывающей течение
линейно упруго запаздывающей жидкости Фойгта.
Библиография: 12 названий.
Аппроксимируемость HNN-расширения с центральными связанными подгруппами корневым классом групп
Authors: Gol'tsov Dmitrii Vladimirovich
Published: May 2015

Рассматривается HNN-расширение группы с центральными
связными подгруппами. Получены несколько условий
аппроксимируемости такого HNN-расширения
корневым классом групп, замкнутым относительно
факторизации.
Библиография: 7 названий.
Обобщенное преобразование Безье
Authors: Volkov Yurik Ivanovich
Published: May 2015

В статье изучаются свойства обобщенного преобразования
Безье, его применения для приближения функций
и построения кривых. Также изучается многомерная версия
этого преобразования.
Библиография: 4 названия.
A Survey from a Large Academic Medical Center
Authors: Homan J.M. , Cimino J.J. , Peters S.G. , Pickering B.W. , Herasevich V. , Ellsworth M.A.
Published: May 2015

Objective: To better understand the literature searching preferences of clinical providers we conducted an institution-wide survey assessing the most preferred knowledge searching techniques.

Materials and Methods: A survey regarding literature searching preferences was sent to 1862 unique clinical providers throughout Mayo Clinic. The survey consisted of 25 items asking respondents to select which clinical scenarios most often prompt literature searches as well as identify their most preferred knowledge resources.

Results: A total of 450 completed surveys were returned and analyzed (24% response rate). 48% of respondents perform literature searches for more than half of their patient interactions with 91% of all searches occurring either before or within 3 hours of the patient interaction. When a search is performed 57% of respondents prefer synthesized information sources as compared to only 13% who prefer original research. 82% of knowledge searches are performed on a workstation or office computer while just 10% occur on a mobile device or at home.

Conclusion: Providers in our survey demonstrate a need to answer clinical questions on a regular basis, especially in the diagnosis and therapy domains. Responses suggest that most of these searches occur using synthesized knowledge sources in the patient care setting within a very short time from the patient interaction.

Citation: Ellsworth MA, Homan JM, Cimino JJ, Peters SG, Pickering BW, Herasevich V. Point-of-care knowledge-based resource needs of clinicians: A survey from a large academic medical center. Appl Clin Inf 2015; 6: 305–317

http://dx.doi.org/10.4338/ACI-2014-11-RA-0104
The Effect of Three Dentinal Sealers on Retention of Crowns cemented with Resin-modified Glass Ionomer Cement: An in vitro Study
Authors: Jain Ashish R , Pradeep R , Janapala Sashi Deepth Reddy , Reddy P Sesha
Published: May 2015

Background

Dentinal sealers (desensitizing agents) are used to protect the pulp from possible injurious effects after tooth preparation and also prevent the penetration of dentinal tubules by bacteria and their products which are currently thought to cause most of the pulpal inflammation under the crowns.

Aim

The purpose of this study is to determine the efficacy of effect of three different desensitizing agents on retention of crowns cemented with resin-modified glass ionomer cement.

Materials and methods

Forty freshly extracted maxillary first premolars were notched for retention and the teeth specimens were mounted in autopolymerising resin. The axial height of all the specimens was 4 mm with a 20° angle of convergence. Impressions of the prepared teeth were made, later waxed invested and casted. Thirty teeth were coated with three different desensitizing agents were used in this study: Cavity varnish (Namuvar, Deepti Dental Products), Glutaraldehyde (Gluma- Heraeus Kulzer), Resin (AdheSE, Ivoclar Vivadent). Ten teeth were not coated with desensitizing agents to act as control group. Independent T test used to compare the mean values between groups.

Results

Tensile strength for average surface area of the groups I, II, III and IV are 0.3759, 0.2375, 0.2411, 0.2348 respectively. The t-test shows ‘p’-value is statistically not significant (p < 0.05) for groups II and III, where as in group IV ‘p’-value is statistically significant (p < 0.01).

Conclusion

The use of AdheSE/resin-based dentinal sealer showed increase in bond strength of the crowns luted with resin-modified glass ionomer cement when compared with control group. This study advocates the use of resin-based sealer or a glutaraldehyde-based sealer before cementation of the crowns. The cavity varnish, however, reduces the bond strength and is not acceptable.

How to cite this article

Janapala SDR, Reddy PS, Jain AR, Pradeep R. The Effect of Three Dentinal Sealers on Retention of Crowns cemented with Resin-modified Glass Ionomer Cement: An in vitro Study. World J Dent 2015;6(1):10-15.
The Use of Magnets in Orthodontics
Authors: Sharma Narendra S , Kamble RH , Shrivastav Sunita , Sharma Preethi
Published: May 2015

Magnets have generated great interest within dentistry. They have been used for various applications in orthodontics and prosthodontics. Earlier use of magnets was limited due to the unavailability of small size magnets, but after the introduction of rare earth magnets and their availability in smaller sizes, their use has increased considerably. The force they deliver can be directed, and they can exert their force through mucosa and bone as well as within the mouth. In orthodontics, they are used for intrusion of teeth, tooth movement along archwires, expansion, retention, in functional appliances and in the treatment of impacted teeth. There are various types of magnets used in the field of orthodontics with their advantages and disadvantages, along with their biological safety which has been discussed in this article. This article reviews various uses of magnets in the field of orthodontics.

How to cite this article

Sharma N, Shrivastav S, Kamble RH, Sharma P. The Use of Magnets in Orthodontics. World J Dent 2015;6(1):45-48.
Role of Periodontist in Pediatric Dental Patients
Authors: Bhardwaj Amit , Grover Harpreet Singh , Singh Yogender
Published: May 2015

Modern age dentistry is very much different from what it was in the past. In this period of super specialization, clinical skills are tuned finely with professional expertise is improved. Interdisciplinary approach is mandatory to deal with any clinical situation to provide optimal and timely treatment results. This paper gives the emphasis on comprehensive management of young people with gingival and periodontal diseases. The paper provides the background to the condition, the possible etiological factors, the prevalence of peridontal diseases and other related conditions. Lastly, there is consideration of the role of the periodontist in interdisciplinary management of the affected child and young patient.

How to cite this article

Grover HS, Singh Y, Bhardwaj A. Role of Periodontist in Pediatric Dental Patients. World J Dent 2015;6(1):49-54.