bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is vitamin D deficiency a risk factor for recurrent aphthous stomatitis? A systematic review and meta‐analysis
Authors: Al‐Maweri Sadeq Ali , Halboub Esam , Al‐Sufyani Ghadah , Alqutaibi Ahmed Yaseen , Shamala Anas , Alsalhani Anas 
Published: September 2019

AbstractObjectivesA few studies have associated vitamin D deficiency with the occurrence of recurrent aphthous stomatitis (RAS). Hence, the aim of the present systematic review and meta‐analysis is to explore such a potential association.MethodsA comprehensive search of PubMed, Scopus, and Web of Science databases was conducted in June 2019. The inclusion criteria were (a) observational studies that assessed the relationship between vitamin D and RAS, and (b) the outcome measures reported quantitative vitamin D levels. Studies without control groups, case series, case reports, experimental studies, letter to editors, reviews, were excluded. The random effects model was conducted for meta‐analyses using RevMan 5.3 software.ResultsFive studies comprising 208 RAS patients and 241 healthy individuals were included. All studies except one reported significantly lower levels of vitamin D in RAS patients compared with the healthy individuals. The results of the pooled 5 studies revealed statistically significant lower levels of vitamin D in RAS patients (Mean Difference (MD) = −9.67 ng/ml, 95% CI = −15.68, −3.65; p ˂ .002).ConclusionThe present meta‐analysis suggests a significant association between low vitamin D levels and RAS. Further well‐designed studies with adequate sample sizes are required to elucidate the role of vitamin D in pathogenesis of RAS.
Analysis of Tornado Reports Through Replicated Spatiotemporal Point Patterns
Authors: González Jonatan A. , Hahn Ute , Mateu Jorge 
Published: September 2019

SummaryUnderstanding the spatiotemporal distribution of tornado events is increasingly imperative, not only because of the natural phenomenon itself and its tremendous complexity but also because we can potentially reduce the risks that they entail. In particular, the US regions are particularly susceptible to tornadoes and they are the focus and motivation of our statistical analysis. Tornado reports can be treated as spatiotemporal point patterns, and we develop some methods for the analysis of replicated spatiotemporal patterns to identify significant structural differences between cold and warm seasons along the years. We extend some existing spatial techniques to the spatiotemporal context to test the null hypothesis that two (or more) observed spatiotemporal point patterns with replications are realizations of point processes that have the same second-order descriptors. In particular, we develop a non-parametric test to approximate the null distribution of the test statistics. We present intensive simulation studies that demonstrate the validity and power of our test and apply our methods to the motivating problem of tornadoes.
Estimation of the number of exposed people during highly pathogenic avian influenza virus outbreaks in EU/EEA countries, October 2016–September 2018
Authors: Adlhoch Cornelia , Miteva Aleksandra , Zdravkova Anna , Miškić Tihana , Kneževic Dražen , Perdikaris Sokratis , Śmietanka Krzysztof , Świętoń Edyta , Kopriva Vilem , Chudý Martin , Romero González Luis Jose , Moreno Gil Ines , Wallén Norell Annica , Verdonck Frank 
Published: September 2019

AbstractWe estimated that more than 11,000 people were exposed to highly pathogenic avian influenza viruses in EU/EEA countries over the outbreak period October 2016–September 2018 by cross‐linking data submitted by Member States to European Food Safety Authority and EMPRES‐i. A stronger framework for collecting human exposure data is required.
Work Values, Emotional Intelligence, Work Environment and Career Commitment among Generation Y: A Proposed Framework
Authors: Damayanti Nur , Yahya Khulida Kirana , Yean Tan Fee 
Published: September 2019

This article reviews the relationship between work values, emotional intelligence, work environment and career commitment in the banking industry. In future, the banking industry will be dominated by the new workforce, millennial generation or Generation Y, a generation whose behaviors and characteristics is different from the older generation before them. Generation Y is known as a very expressive generation, who as employees are confident but lacks career commitment and not interested in meticulous details; they present different views on work and duties. Generation Y, unlike employees of previous generations, tend to think that they have the competitive edge; no emotional connection or workplace loyalty. When job expectations are not met, they are more likely to switch jobs. The proposed study will be useful for all leaders and managers in the banking industry to gain a greater understanding of the work values of Generation Y employees. Consequently, this study may contribute useful knowledge in gaining career commitment among the Generation Y workforce
Revamping the design of Preschoolers Islamic Education by Integrating Islamic Design Principles and Cognitive Theory of Multimedia Learning: A Needs Assessment Study
Authors: Idris Wan Irma Sabrina , Abdul Razak Rafiza , Halili Siti Hajar , Abdul Rahman Siti Soraya , Hamzah Hasleena 
Published: September 2019

This study aims at identifying the needs in applying Islamic Design Principles in developing multimedia learning for Islamic Education among children. Teaching methods of Islamic education have not seen much improvement and lack of creativity. Current designs and content of multimedia learning materials were not suitable in teaching Islamic education. Thus this study initiated in integrating Islamic design principles; 1) Tawheed, 2) Dhikir 3) Haya and 4) Iqtisad with Cognitive Multimedia Learning Theory. It involved a needs analysis survey research design concerning parents and teachers of preschool as participants. The result of this study indicated positive responses received upon this matter indicating that the elements of Islamic design principles were relevant in multimedia learning for preschool Islamic Education. The integration of multimedia learning theory and Islamic Design Principles in designing multimedia learning for children. This was because the impacts of multimedia learning and Islamic design principles were important for the future of early children education, it was sensible for Islamic design principles were applied to multimedia learning content. There was a need to develop learning aids in teaching Islamic values education to the children. Multimedia learning can help in sculpting the Islamic character of the children while coaching them the virtuous values in Islam; an example of the ethic in Prophet Muhammad (P.B.U.H.), good behavior and action will help the children in their personal life. Besides, this paper will help instructional design to design and develop a multimedia learning for Islamic preschool in future.
The Awareness Level among the Perak Muslim Community towards the Perak Ar-Ridzuan Waqf/ Tahap Kesedaran Masyarakat Islam di Perak Mengenai Wakaf Perak Ar-Ridzuan
Authors: Muhammad Fidlizan , Abdul Razak Azila , Awang Salwa Amirah , Mohd Hussin Mohd Yahya , Aliyasak Mohd Zul Izwan 
Published: September 2019

Waqf is an essential element in the development of Islam. However, there are many existing issues in the management and development of waqf nowadays that inhibit the benefits of development to be enjoyed by the society. The Perak Ar-Ridzuan Waqf (WPAR) was established in 2015 with the aim to manage the development of waqf in Perak efficiently. Nevertheless, the issue of funding shortage to expedite the development has been the key issue. Therefore, this study purposively to identify the level of awareness of the Muslim community in the state of Perak regarding WPAR from the aspects of establishment, development planning, waqf method and others. This study employs the quantitative method through the use of questionnaire forms as the instrument to obtain the data that contains two sections in which the part A is for respondents' profile and the part B is specifically for respondents' knowledge on WPAR. A total of 312 respondents were involved in this study. Analysis of descriptive and crosstab were applied to analyze the gathered data. The finding of the study shows that the level of knowledge among the Muslim community pertaining WPAR in the planned development projects, waqf method and matching donation incentive prepared by the Maybank Islamic were unknown by the majority of respondents. Similar situations occured among respondents who are and had served as the mosque committees. The implication of this study proves that the existence of WPAR is still less known to the Muslim community in Perak. This condition needs a serious attention from the authority to ensure that the establishment of WPAR is able to attain its goal and realize all waqf development projects according to the allocated funding and time.
Second Law Analysis of an Energy Storage System Consisting of an Electrolysis Plant and the Graz Cycle With Internal H2/O2 Combustion
Authors: Dybe Simeon , Tanneberger Tom , Stathopoulos Panagiotis 
Published: September 2019

Abstract
The expansion of renewable energy generation must go hand in hand with measures for reliable energy supply and energy storage. A combination of hydrogen and oxygen as storing media provided from electrolysis at high pressure and zero emission power plants is a very promising option. The Graz cycle is an oxy-fuel combined power cycle that can operate with internal H2/O2 combustion and steam as working fluid. It offers thermal efficiencies up to 68.5% (lower heating value - LHV). This work applies a second law analysis to the Graz cycle and determines its exergetic efficiency. Exergy destruction is broken down to the cycle's components, thus providing insights on the location and magnitude of the cycle's inefficiencies. A sensitivity analysis identifies the cycle's exergetic and energetic efficiency as a function of representative parameters, offering an approach for future improvements. The combination of the cycle with an electrolysis plant is subsequently analyzed as an electric energy storage system. The round trip efficiency of the storage and back conversion system is computed by taking into account the additional compression of the reactants. As part of this analysis, the effect of the electrolyzer's operational pressure is studied by comparing several commercial electrolyzers.
Numerical Research on the Toroidal Shock Wave Focusing Detonation Initiation
Authors: Chen Xiang , Zhao Ningbo , Zheng Hongtao , Jia Xiongbin , Liu Shizheng , Liu Qingbo 
Published: September 2019

Abstract
Pressure gain combustion (PGC) is considered to be a potential technology to increase the cycle efficiency of gas turbine. As one viable candidate for PGC, rotating detonation engine (RDE) draws more attention due to its significant advances in continuous mode of operation. In practical, one of the basic challenges for RDE application is to reliably initiate detonation wave. For this purpose, both detonation initiation mechanism and enhancement approach are urgently needed to be understood. In this work, a toroidal shock wave focusing detonation initiator is presented. On this basis, the two-dimensional numerical simulations are carried out to investigate the detonation initiation characteristics by using the toroidal shock wave focusing. All of the flame acceleration, shock wave focusing, detonation wave forming, and propagation are analyzed in detail. The numerical results show that the toroidal shock wave focusing initiator developed in this study can rapidly realize the detonation initiation over a short distance and performs significantly better than the traditional smooth or obstructed tube based imitators under different operating conditions. Under the same operating condition, the novel developed initiator decreases time of 59.2% and distance of 84.7% for the smooth tube based initiator, and time of 52% and distance of 78.9% for the obstructed one. Besides, the multifield analysis indicates that both the local explosion induced by shock wave focusing in concave cavity and the entrainment vortex generated by shock wave and jet flame in front of diaphragm are important mechanisms to initiate detonation wave. This study is expected to enhance the understanding of the physical mechanism of shock wave focusing detonation initiation and contribute to the development of detonation propulsion technology.
Geometric Mistuning Reduced-Order Model Development Utilizing Bayesian Surrogate Models for Component Mode Calculations
Authors: Beck Joseph A. , Brown Jeffrey M. , Kaszynski Alex A. , Carper Emily B. , Gillaugh Daniel L. 
Published: September 2019

AbstractIntegrally bladed rotors (IBRs) are meant to be rotationally periodic structures. However, unique variations in geometries and material properties from sector-to-sector, called mistuning, destroy the structural periodicity. This results in mode localization that can induce forced response levels greater than what is predicted with a tuned analysis. Furthermore, mistuning and mode localization are random processes that require stochastic treatments when analyzing the distribution of fleet responses. Generating this distribution can be computationally intensive when using the full finite element model (FEM). To overcome this expense, reduced-order models (ROMs) have been developed to accommodate fast calculations of mistuned forced response levels for a fleet of random IBRs. Usually, ROMs can be classified by two main families: frequency-based and geometry-based methods. Frequency-based ROMs assume mode shapes do not change due to mistuning. However, this assumption has been shown to cause errors that propagate to the fleet distribution. To circumvent these errors, geometry-based ROMs have been developed to provide accurate predictions. However, these methods require recalculating modal data during ROM formulations. This increases the computational expense in computing fleet distributions. A new geometry-based ROM is presented to reduce this cost. The developed ROM utilizes a Bayesian surrogate model in place of sector modal calculations required in ROM formulations. The method, surrogate modal analysis for geometry mistuning assessments (SMAGMA), will propagate uncertainties of the surrogate prediction to forced response. ROM accuracies are compared to the true forced response levels and results computed by a frequency-based ROM.
Nondimensional Parameters’ Effects on Hybrid Darrieus–Savonius Wind Turbine Performance
Authors: Roshan Armin , Sagharichi Amir , Maghrebi Mohammad Javad 
Published: September 2019

Abstract
Vertical axial wind turbines are the most commonly used turbines in residential and urban areas. This paper investigates the effect of combining Darrieus and Savonius wind turbines on power output and introduces a wind turbine with high starting torque addition to the wide working domain. A two-dimensional computational fluid dynamics transient simulation is developed, and a moving mesh is implemented for rotating moving parts. Comprehensive research has been carried out to investigate the effects of the initial overlap ratio (ɛ), arc angle Ø, and curvature (α) of Savonius blades on the performance of the turbine and 18 models are simulated at seven tip speed ratios. The results showed that combining the Darrieus turbine with the Savonius turbine has a favorable effect on self-starting performance. Also, it was observed that by changing each of the parameters, the primary model performance could be significantly improved. Finally, it is concluded that ɛ = 0.25, α = 0.25, and ∅ = 150 deg are the optimum values of the parameters which increase turbine power output compared to conventional vertical-axis turbines.
Flat Spiral Coil Design for Higher Riveting Force and Energy Saving in the Electromagnetic Riveting Process
Authors: Cui Junjia , Zeng Chaochao , Jiang Hao , Li Guangyao 
Published: September 2019

AbstractElectromagnetic riveting (EMR) belongs to the green manufacturing process, which has the advantages of low noise, no pollution, and large riveting force. In this paper, the influences of structural parameters of a flat spiral coil on riveting force and energy saving were investigated, and the cross-section geometry, base angle, and height of the coil section were designed. The EMR simulation models with fully coupled electromagnetic–thermal–mechanical were built in ls-dyna software, and the riveting force was adopted to assess the performances of different types of coils. The results showed that the riveting force given by trapezoid cross-section coil was the largest compared with rectangular, pentagonal, and circular types. Moreover, the increase in the base angle and height of the coil section had a positive effect on improving the riveting force and energy saving. In addition, weights analyses showed that the contribution rates of three structural parameters (length of the bottom edge, base angle, and height) of the coil to energy saving were 0.5231, 0.2347, and 0.2422, respectively. In general, the riveting force was improved and discharge energy was saved by adjusting geometric parameters of the coil. The research could provide guidance for the coil design in the EMR process.
Evaluation of Thermal Stratification Inside a New Model of Spherical Water Storage Tank Using a Computational Fluid Dynamics 6 Degrees of Freedom Solver
Authors: Bouzaher Mohamed Taher , Noureddine Belghar , Bensaci Charaf-Eddine , Bouchahm Nora , Guerira Belhi 
Published: September 2019

Abstract
In this work, a computational analysis of a spherical solar hot water storage tank during the discharging process is carried out by using the commercial code ansys-fluent.15. The study investigates a new type of spherical heat storage tank. A hinged baffle is fixed at the tank vertical axis to increase the discharge flow rate without a thermocline layer. The dynamic mesh LAYERING technique is used to update the computational domain during the movement of the hinged baffle. The passive pitching of the submerged baffle is due to the fluid-dynamic loads. This model limits the mixture between hot and cold water regardless of the inlet flow rate. A comparative study between tanks with typical diffusers and the hinged baffle model is considered. The comparison of the computational fluid dynamics results with available experimental data showed a good agreement. Examinations of the temperature contours indicate that for the typical models, the interaction between the incoming cold water and the stored hot water gives rise to a thick thermocline layer where its temperature and thickness are related to the intensity of the mixing process. The suggested model shows high stratification efficiency along the discharging process.
Evaluation of Two-Phase Frictional Pressure Drop Correlations Against Experimental Data
Authors: Li Wei , Shen Kunrong , Zheng Boren , Ma Xiang , Sherif S. A. , He Yan 
Published: September 2019

AbstractResults are presented here from an experimental investigation on tube side two-phase characteristics that took place in four tested tubes—the 1EHT-1, 1EHT-2, 4LB, and smooth tubes. The equivalent outer diameter of the tube was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318 K, over a mass flow range of 150–450 kg m−2 s−1, with inlet and outlet vapor qualities of 0.8 and 0.2, respectively. Evaporation tests were performed at a saturation temperature of 279 K, over a mass flow range of 150–380 kg m−2 s−1, with inlet and outlet vapor qualities of 0.2 and 0.8, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model. The separated flow approaches presented predictions with average MAEs of 24.9% and 16.4% for condensation and evaporation data, respectively, while the average MAEs of the homogeneous flow model were 31.6% and 43.4%, respectively. Almost all the identified correlations underestimated the frictional pressure drop of the 4LB tube with MAEs exceeding 30%. An earlier transition of different flow patterns was expected to occur in the EHT tubes while developing a new diabatic flow pattern map is needed for the 4LB tube. A new correlation was presented based on the two-phase multiplier Φ and the Martinelli parameter Xtt, which exhibited excellent predictive results for the experimental data.
Numerical Investigation of a Turbulent Jet Flame With a Compact Skeletal Mechanism
Authors: Chopkap Noume Hermann , Bomba Valentin , Obounou Marcel 
Published: September 2019

Abstract
The present work assesses the capabilities of a compact skeletal mechanism, derived using an in-house reduction code, to accurately model chemical processes in a turbulent CH4/H2/N2 flame. To this end, a numerical investigation of the DLR-A flame is performed using the free and open-source code openfoam with the derived mechanism. Specifically, the numerical investigation is performed using the Reynolds-averaged Navier–Stokes (RANS) approach and a compact skeletal mechanism consisting of 51 elementary reactions among 21 species. The skeletal mechanism is derived from the GRI3.0 mechanism using an improved multistage reduction method. The k − ɛ model is used as a closure for the RANS equations, while the source terms in the species and energy transport equations are closed by the partially stirred reactor (PaSR) model. The radiation term is modeled by the P-1 model. The numerical results show a good agreement with the experimental data.
The State-of-the-Art Technology of H-Type Darrieus Wind Turbine Rotors
Authors: Jain Siddhant , Saha Ujjwal K. 
Published: September 2019

AbstractThere has been a resurgence of interest in the development of small-scale vertical-axis wind turbines (VAWTs) in the past few decades as is evident from the plethora of published scientific work. This attention may be attributed to the desperate need for cheaper, cleaner, and off-grid mechanisms for generating electric power. In such hasty scenario, VAWTs are being considered as one of the potential solution for small-scale power generation. Among the VAWTs, H-type Darrieus rotors have undergone extensive exploration. In this review work, an attempt has been made to assemble all the major areas of research done in the field of H-type Darrieus rotor development. These areas include the aerodynamic models, computational fluid dynamics (CFD) methods and turbulence models, self-starting and dynamic stalling behavior, blade-vortex interaction and wake studies, and blade designs and optimization studies, besides topics of special interest like blade curvature effects and skewed flows. Overall, the work gives a comprehensive review of the state-of-the-art technology of the H-type Darrieus rotor. Finally, recommendations have been made for each of the areas keeping in view of the technological development.