bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear‐frictional contact model for 3D discrete element simulations of granular systems
Authors: Kuhn Matthew R. , Suzuki Kiichi , Daouadji Ali
Published: September 2019

The linear‐frictional contact model is the most commonly used contact mechanism for discrete element (DEM) simulations of granular materials. Linear springs with a frictional slider are used for modeling interactions in directions normal and tangential to the contact surface. Although the model is simple in two dimensions, its implementation in 3D faces certain subtle challenges, and the particle interactions that occur within a single time step require careful modeling with a robust algorithm. The paper details a three‐dimensional algorithm that accounts for the changing direction of the tangential force within a time step, the transition from elastic to slip behavior within a time step, possible contact sliding during only part of a time step, and twirling and rotation of the tangential force during a time step. Without three of these adjustments, errors are introduced in the incremental stiffness of an assembly. Without the fourth adjustment, the resulting stress tensor is not only incorrect but it is also no longer a tensor. The algorithm also computes the work increments during a time step, both elastic and dissipative.
Design and analysis adaptivity in multiresolution topology optimization
Authors: Gupta Deepak K. , van Keulen Fred , Langelaar Matthijs
Published: September 2019

Multiresolution topology optimization (MTO) methods involve decoupling of the design and analysis discretizations, such that a high‐resolution design can be obtained at relatively low analysis costs. Recent studies have shown that the MTO method can be approximately 3 and 30 times faster than the traditional topology optimization method for two‐dimensional (2D) and three‐dimensional (3D) problems, respectively. To further exploit the potential of decoupling analysis and design, we propose a dp‐adaptive MTO method, which involves locally increasing/decreasing the polynomial degree of the shape functions (p) and the design resolution (d). The adaptive refinement/coarsening is performed using a composite refinement indicator that includes criteria based on analysis error, presence of intermediate densities, as well as the occurrence of design artifacts referred to as QR‐patterns. While standard MTO must rely on filtering to suppress QR‐patterns, the proposed adaptive method ensures efficiently that these artifacts are suppressed in the final design, without sacrificing the design resolution. The applicability of the dp‐adaptive MTO method is demonstrated on several 2D mechanical design problems. For all the cases, significant speedups in computational time are obtained. In particular for design problems involving low material volume fractions, speedups of up to a factor of 10 can be obtained over the conventional MTO method.
The capacity for oestrogen to influence obesity through brown adipose tissue thermogenesis in animal models: A systematic review and meta‐analysis
Authors: Sievers Will , Rathner Joseph A. , Kettle Christine , Zacharias Anita , Irving Helen R. , Green Rodney A.
Published: September 2019

Pharmacological interventions to aid weight loss have historically targeted either appetite suppression or increased metabolic rate. Brown adipose tissue (BAT) possesses the capacity to expend energy in a futile cycle, thus increasing basal metabolic rate. In animal models, oestrogen has been implicated in the regulation of body weight, and it is hypothesized that oestrogen is acting by modulating BAT metabolism. A systematic search was performed, to identify research articles implementing in vivo oestrogen‐related interventions and reporting outcome measures that provide direct or indirect measures of BAT metabolism. Meta‐analyses were conducted where sufficient data were available. The final library of 67 articles were predominantly in rodent models and provided mostly indirect measures of BAT metabolism. Results of this review found that oestrogen's effects on body weight, in rats and possibly mice, are likely facilitated by both metabolic and appetitive mechanisms but are largely only found in ovariectomized models. There is a need for further studies to clarify the potential effects of oestrogen on BAT metabolism in gonad‐intact and castrated male animal models.
On the formulation of anisotropic plasticity for polymeric composites‐ rate‐dependent models with non‐linear isotropic/kinematic hardening
Authors: G Nagaraja Swaroop , Schuecker Clara
Published: September 2019

The use of fiber‐reinforced composites as a primary structural component in automotive and aerospace industries has significantly increased over time, due to their great weight saving potential. Consequently, the predictive modeling of the non‐linear behavior of composites has been a topic of intensive research over the last years. Experimental data shows non‐linear response that is direction dependent due to the fibrous micro‐structure. Since typical fiber materials can be considered essentially as linear elastic, the non‐linearities are attributable to the inelastic deformation in the matrix, occurring at relatively small strains.

This study presents a relatively general, homogenized formulation of anisotropic plasticity for application to (mainly) polymeric composites. A constitutive model has been developed to simulate the non‐linearities exhibited by the composite, generating the anisotropic elastic and plastic response functions with the aid of representation theorems. Rate‐independent versions using isotropic hardening have previously been proposed by the authors. The main focus of this work is the extension to include rate dependency and non‐linear kinematic hardening effects. Selected numerical simulations which serve the purpose of illustrating the formulation discussed herein, are presented at the end.
Implementing a microstructure model with self‐organization into a FEM Software
Authors: Oelsch Erik , Wulf Hans , Ihlemann Jörn
Published: September 2019

Experimental investigation of filled rubber reveal several complex properties like hysteresis, permanent set, Mullins‐effect. The connection of these properties to the microstructure is still unclear. The theory of Self‐Organizing Linkage Patterns (SOLP) by Ihlemann is an approach that relies crucially on deviations from average distributions. Specifically, it states that deformed rubber develops a pattern based on physical linkages which is characterized by regions of high and low linkage density. On this basis, all complex material properties can be explained as result of an adaption of the linkage pattern to the applied deformation. The theory is verified by a simulation program which uses a very abstract model of the molecular structure of filled rubber. Furthermore a FEM software is used to mix serial and parallel connection of single SOLP systems.
Non‐material finite element rod model for out‐of‐plane bending of an elastic strip with natural curvature
Authors: Schmidrathner Christian , Vetyukov Yury
Published: September 2019

A novel finite element formulation for elastic unshearable rods in three‐dimensional space is presented. Looking forward to future implementations of axially moving belts, we use a mixed Eulerian‐Lagrangian kinematic formulation, which has the advantage that the element nodes are fixed in one spatial coordinate and the material points are flowing through the mesh, hence it is possible to discretize the elements in the free spans coarser than the ones in contact with the pulleys. Here, we present the solution of hanging rods with a flat cross‐section including a natural curvature, which causes an out‐of‐plane bending as well as torsion of the rod. For validation purposes we limit ourselves to equilibrium solutions (for which purely Lagrangian elements would be also applicable) with clamped boundary conditions. The results are compared with a shell model of the hanging strip. Preliminary results concerning the frictionless contact problem for a steel belt hanging on two pulleys are discussed.
Polymorphic Uncertainty Quantification of Computational Soil and Earth Structure Simulations via the Variational Sensitivity Analysis
Authors: Henning Carla , Ricken Tim
Published: September 2019

Due to the high natural variability of mechanical properties in soil, comparatively high safety factors are still used for the dimensioning of earth structures. Back in the 1970s, probabilistic concepts were recommended as the technical standard for geotechnical applications. However, their dissemination failed because of the high computation costs on one hand and, on the other hand, often not enough data being available to carry out such analyses.

By means of increasing computing power and enhanced mathematical models, a better understanding of the nature and influence of the uncertainties and errors could help to develop a more reliable risk assessment and to reduce inefficient safety factors. For this reason, we perform a research project within the priority program SPP 1886, installed by the DFG and focused on polymorphic uncertainty quantification. In the present subproject (SP 12), the focus is driven on quantification and assessment of polymorphic uncertainties in computational simulations of earth structures, especially for fluid‐saturated soils. To describe the strongly coupled and transient solid‐fluid response behavior, the Theory of Porous Media (TPM) is used and solved via the Finite Element Method (FEM).

The goal is to overcome the above mentioned two problems by providing suitable numerical methods. Motivated by structural optimization research, the Variational Sensitivity Analysis (VSA) provides detailed prior information about the current equilibrium state for subsequent analyzes. On its basis, the information for which parameters and in which areas of the simulation domain a more detailed investigation is required can be obtained in advance. The method enables an immediate decision support, e.g. for site investigators or researchers. Not only the computational effort but also the applicability to any arbitrary FE‐Model are great advantages of this approach.
Modeling of active multiphase materials
Authors: Sauerwein Malte , Steeb Holger
Published: September 2019

In this contribution, material modeling and experimental investigations towards a chemically‐active multiphase material are presented. The material under consideration consists of a solid skeleton, while the pore space is filled with multiple reactive pore fluids. Here, the pore space is simultaneously filled with a pore liquid and a hydrogel made of a granulate of superabsorbent polymers (SAP). The three‐phase material is modeled within a continuum mixture theory based on the Hybrid Mixture Theory (HMT). Due to the hydrophilic character, the hydrogel is able to absorb large amounts of the pore liquid and binds it to the polymer structure. As a consequence, the saturation of free liquid in the void space decreases during the absorption, which also affects the permeability with respect to seepage flow. Since the absorption dynamics as well as the maximum water capacity of the hydrogel depend highly on external stimuli, e.g. the pore fluid chemistry, temperature, electric and magnetic fields, hydrogels are usually called active or functional materials. The hydrogel material used in this study is sensitive with respect to the ion concentration of the surrounding pore liquid.
The role of degenerate mobilities in Cahn‐Hilliard models
Authors: Dziwnik Marion
Published: September 2019

The present work provides an insight into the role of degenerate mobilities in phase field models and in particular their influence on the evolution of the interface. The equation of interest is the Cahn‐Hilliard equation (in two space dimensions) with a polynomial double well free energy and different order‐parameter dependent, degenerate mobilities. According to the preliminary work [1], considering an anisotropic version of the equation, the asymptotic sharp interface limit subtly dependents on the degeneracy of the mobility. Whilst a quadratic degenerate mobility leads to a sharp interface model where bulk diffusion is present at the same asymptotic order as surface diffusion, a bi‐quadratic degenerate mobility leads to a sharp interface model where bulk diffusion is subdominant. The present study continues the preliminary work and shows that the type of the degeneracy has a qualitative impact on the evolution: Considering numerical simulations of the dewetting process of a thin solid film with four‐fold anisotropic surface energy, the evolution with bi‐quadratic degenerate mobility turns out to be more effective for film pinch‐off than with quadratic degenerate mobility. An extension to the isotropic Cahn‐Hilliard equation ensures that the characteristic difference in the pinch‐off behavior is in fact mobility‐dependent.
A coupled isogeometric boundary element and finite element method for electro‐mechanical interaction
Authors: Rajski Michal P. , Harmel Maximilian , Sauer Roger A.
Published: September 2019

Solving multiphysical problems is a challenging task in computational engineering both in regard to accuracy and efficiency. Finite element methods (FEM) – while very popular and well established for standard problems – are less straightforward for problems involving interfaces moving due to the influence of external fields. Such problems are characterized by additional challenges, such as mesh dynamics, re‐meshing and possible unboundedness of the external field. The boundary element method (BEM) can help to overcome these challenges. In the BEM formulation, the problem is solved solely from the boundary of the domain. This property – in conjunction with finite element shell and membrane formulations – leads to a very interesting coupled method, requiring only the surface discretization to solve multiphysical interface problems. To show the underling idea of the formulation, the electro‐mechanical interaction between two charged shells is considered as an example.
Inverse dynamics of underactuated flexible mechanical systems
Authors: Ströhle Timo , Betsch Peter
Published: September 2019

An alternative approach to the inverse dynamics of flexible mechanical systems is presented. In contrast to a sequential discretization in space and time a simultaneous space‐time discretization is applied to the problem of inverse dynamics of underactuated systems. In particular, a space‐time finite element formulation will be compared with a formulation which is based on the method of characteristics. Numerical examples are presented which underline the importance of solving this class of problems in space and time simultaneously.
Modeling and Simulation of the Aqueous Humor Flow in the Human Eye
Authors: Dörsam Simon , Olkhovskiy Vladislav , Friedmann Elfriede
Published: September 2019

A mathematical model for the physiology of the aqueous humor flow in the human eye is developed. The governing equations are the Stokes and Darcy equations with certain physical characteristic parameters. We extend the model to describe diseases like glaucoma and retinal diseases and model their treatment. The developed models are solved with the mixed Finite Element method and the flow is visualized in a three‐dimensional eye model. An individual physiology of a healthy eye or of an eye with glaucoma can be represented by adjusting the parameters. We calculate the intraocular pressure and quantify the pressure decrease after a certain treatment. In case of retinal diseases we calculate the drug distribution and quantify the drug amount at the location of action.
Validation of an administrative claims coding algorithm for serious opioid overdose: A medical chart review
Authors: Mountcastle Sally B. , Joyce Andrew R. , Sasinowski Maciek , Costello Nancy , Doshi Snehal , Zedler Barbara K.
Published: September 2019

Purpose

A standardized definition for serious opioid overdose has not been clearly established for disease surveillance or assessing the impact of risk mitigation strategies. The purpose of this study was to use medical chart review to clinically validate a claims‐based algorithm to identify serious opioid overdose events.

Methods

The algorithm for serious opioid overdose required an opioid poisoning or external cause ICD‐9‐CM code occurring within 1 day of (a) an adverse effect code for serious central nervous system or respiratory depression or (b) a mechanical ventilation or critical care CPT code. The claims coding algorithm identified a sample of 145 individuals 18 years or older among patients that presented to the emergency department of two large hospitals in metropolitan Atlanta, Georgia from January 2014 to August 2015. Claims‐defined cases were evaluated against rigorous clinical definitions for serious opioid overdose using (a) literature‐based criteria for typical clinical manifestations of opioid overdose and/or (b) clinical response to the opioid‐specific reversal agent naloxone. The positive predictive value (PPV) for a serious opioid overdose was calculated as the percentage of clinically confirmed cases (definite or probable).

Results

Among 140 evaluable claims‐defined cases, 107 fulfilled clinical criteria for a serious opioid overdose [95 definite and 12 probable; PPV of 76.4% (95% CI 69.4%, 83.5%)]. Among 30 nonconfirmed cases, 20 were polyintoxications involving one or more nonopioid psychoactive agents.

Conclusions

An administrative claims coding algorithm for serious opioid overdose had high clinical predictive performance in a medical chart review.
Synthesis and characterization of asymmetric bismaleimide oligomers with improved processability and thermal/mechanical properties
Authors: Yu Ping , Zhang Yan‐li , Yang Xue , Pan Li‐jing , Dai Zhi‐yao , Xue Min‐zhao , Liu Yan‐gang , Wang Wei
Published: September 2019

Novel asymmetric bismaleimide (BMI) oligomers with different molecular weights and dianhydrides were designed and synthesized by 3,4′‐oxydianiline (3,4′‐ODA), 2,3,3′,4′‐oxydiphthalic dianhydride (a‐ODPA), and 2,3,3′,4′‐biphenyltetracarboxylic dianhydride (a‐BPDA). The chemical structures of BMI oligomers were confirmed by Fourier transform infrared spectrometry (FTIR) and gel permeation chromatography (GPC). X‐ray diffraction (XRD) exhibited broad peaks, suggesting amorphous structures. Heat flow curves of oligomers measured by differential scanning calorimeter (DSC) displayed wide processing window due to low glass transition temperatures (Tg). BMI oligomers exhibited high solubility in common organic solvents. Particularly, the OD‐BMI‐1 oligomer exhibited excellent solubility of more than 50 wt% in DMAc solvent. Tg value and minimum complex viscosity of OD‐BMI‐1 oligomer were only 121 °C and 8.1 Pa · s, respectively. The cured BMI resins possess high thermal and thermal‐oxidative stability. The Tg and the temperature of 5% weight loss in nitrogen were above 256 and 449 °C, respectively, and the residual weight percentages at 800 °C were all >49%. Moreover, films made of BMI resins exhibited excellent mechanical properties flexibility, as confirmed by photograph and DMA results of films. The elongation at break of the prepared films was found to be high (almost >9.6%). POLYM. ENG. SCI., 59:2265–2272, 2019. © 2019 Society of Plastics Engineers
Spatio‐temporal variability of cloud cover types in West Africa with satellite‐based and reanalysis data
Authors: Danso Derrick Kwadwo , Anquetin Sandrine , Diedhiou Arona , Lavaysse Christophe , Kobea Arsène , Touré N'Datchoh Evelyne
Published: September 2019

This study aims to understand and document the occurrence and variability of cloud cover types in West Africa (WA). Investigations are carried out with a 10‐year hourly record of two cloud data products: CERES passive satellite observations and ERA5 reanalysis. The seasonal evolutions of high (HCC), middle (MCC), low (LCC) and total (TCC) cloud cover are examined. Both products agree on the seasonal and spatial occurrence of cloud cover, although CERES presents lower values of cloud fraction than ERA5 which is partly attributed to the inability of the satellite sensor to detect optically thin clouds in the atmosphere. Southern WA is found to be cloudier than other parts of the region in all seasons with mean TCC fractions of 70 and 80% for CERES and ERA5 respectively during the monsoon season. In all seasons, the presence of LCC over large areas of the Sahel/Sahara region is noted in the CERES product. This could be due to a possible misinterpretation of Saharan dust as low clouds which may have thus, caused it to overestimate the occurrences and fractions of LCC over this region. Northern WA is associated with higher frequencies of no cloud occurrence events, unlike the south where cloudless skies are rarely observed. Furthermore, in southern WA, overcast conditions of LCC are observed for a significant number of times (up to 20% of the time during the rainy season in CERES and 40% in ERA5). The climatology of cloud cover presented in this study could be useful for the planning of solar energy projects.
Automated identification of avian vocalizations with deep convolutional neural networks
Authors: Ruff Zachary J. , Lesmeister Damon B. , Duchac Leila S. , Padmaraju Bharath K. , Sullivan Christopher M.
Published: September 2019

Passive acoustic monitoring is an emerging approach to wildlife monitoring that leverages recent improvements in automated recording units and other technologies. A central challenge of this approach is the task of locating and identifying target species vocalizations in large volumes of audio data. To address this issue, we developed an efficient data processing pipeline using a deep convolutional neural network (CNN) to automate the detection of owl vocalizations in spectrograms generated from unprocessed field recordings. While the project was initially focused on spotted and barred owls, we also trained the network to recognize northern saw‐whet owl, great horned owl, northern pygmy‐owl, and western screech‐owl. Although classification performance varies across species, initial results are promising. Recall, or the proportion of calls in the dataset that are detected and correctly identified, ranged from 63.1% for barred owl to 91.5% for spotted owl based on raw network output. Precision, the rate of true positives among apparent detections, ranged from 0.4% for spotted owl to 77.1% for northern saw‐whet owl based on raw output. In limited tests, the CNN performed as well as or better than human technicians at detecting owl calls. Our model output is suitable for developing species encounter histories for occupancy models and other analyses. We believe our approach is sufficiently general to support long‐term, large‐scale monitoring of a broad range of species beyond our target species list, including birds, mammals, and others.
Reduction of Metal Ion Content in Jatropha Biodiesel by Ion Exchange
Authors: Wang Wenchao , Chen Yong , Li Fashe , Li Ying
Published: September 2019

This study is focused on the optimization and decreasing the metal ion content in jatropha biodiesel using an ion exchange resin. The changes in the organic composition of jatropha oil biodiesel were measured by GCMS before and after passing the biodiesel over the ion exchange resin. The chelating efficiency of ion exchange resin on metal ions, including potassium, calcium, sodium, and magnesium, in jatropha biodiesel either treated with different oleic acid content or having different oxidation degrees was evaluated. The results showed that the ion exchange resin can effectively decrease the metal ions content in jatropha biodiesel without producing harmful substances to environment and human body. Moreover, the increase in oleic acid content and oxidation in Jatropha biodiesel affects the ability of ion exchange resins to sequester metal ions.
Cyclodextrin‐Calixarene Nanosponges as Potential Platforms for pH‐Dependent Delivery of Tetracycline
Authors: Fontana Rosa Maria , Milano Nicola , Barbara Lorenzo , Di Vincenzo Antonella , Gallo Giuseppe , Meo Paolo Lo
Published: September 2019

Four mixed cyclodextrin‐calixarene nanosponges were tested as possible Drug Delivery Systems, using Tetracycline antibiotic as a suitable model drug. The selected nanosponges featured a different composition ratio between the two host co‐monomer components, and the possible presence of ionisable amine or carboxyl groups deriving from chemical post‐modification. The pH‐dependent absorption and release abilities of the materials were verified; in particular release kinetics showed the occurrence of a simple first‐order profile. The antibacterial activity of nanosponge‐tetracycline composites suitably prepared under sterile conditions was assayed towards both Gram‐positive and Gram‐negative typical bacterial strains, showing in some cases an interesting improvement of the biocidal activity.
Nanosize Cation‐Disordered Rocksalt Oxides: Na2TiO3–NaMnO2 Binary System
Authors: Kobayashi Tokio , Zhao Wenwen , Rajendra Hongahally Basappa , Yamanaka Keisuke , Ohta Toshiaki , Yabuuchi Naoaki
Published: September 2019

To realize the development of rechargeable sodium batteries, new positive electrode materials without less abundant elements are explored. Enrichment of sodium contents in host structures is required to increase the theoretical capacity as electrode materials, and therefore Na‐excess compounds are systematically examined in a binary system of Na2TiO3–NaMnO2. After several trials, synthesis of Na‐excess compounds with a cation disordered rocksalt structure is successful by adapting a mechanical milling method. Among the tested electrode materials, Na1.14Mn0.57Ti0.29O2 in this binary system delivers a large reversible capacity of ≈200 mA h g−1, originating from reversible redox reactions of cationic Mn3+/Mn4+ and anionic O2−/On− redox confirmed by X‐ray absorption spectroscopy. Holes in oxygen 2p orbitals, which are formed by electrochemical oxidation, are energetically stabilized by electron donation from Mn ions. Moreover, reversibility of anionic redox is significantly improved compared with a former study on a binary system of Na3NbO3–NaMnO2 tested as model electrode materials.
Metal Nanoclusters Stabilized by Selenol Ligands
Authors: Kang Xi , Zhu Manzhou
Published: September 2019

The past decades have witnessed great advances in controllable synthesis, structure determination, and property investigation of metal nanoclusters. Selenolated nanoclusters, a special branch in the nanocluster family, have attracted great interest in these years. The electronegativity and atomic radius of selenium is different from sulfur, and thus the selenolated nanoclusters are anticipated to display different electronic/geometric structures and distinct chemical/physical properties relative to their thiolated analogues. This review covers the syntheses, structures, and properties of selenolated nanoclusters (including Au, Ag, Cu, and alloy nanoclusters). Ligand effects (between SeR and SR) on nanocluster properties, including optical absorption, stability, and electrochemical properties, are disclosed as well. At the end of the review, a scope for improvements and future perspectives of selenolated nanoclusters is highlighted. The review hopefully opens up new horizons for cluster scientists to synthesize more selenolated nanoclusters with novel structures and properties. This review is based on publications available up to May 2019.
Micro‐/Nanostructured Interface for Liquid Manipulation and Its Applications
Authors: Zuo Yinxiu , Zheng Liuzheng , Zhao Chao , Liu Hong
Published: September 2019

Understanding the relationship between liquid manipulation and micro‐/nanostructured interfaces has gained much attention due to the wide potential applications in many fields, such as chemical and biomedical assays, environmental protection, industry, and even daily life. Much work has been done to construct various materials with interfacial liquid manipulation abilities, leading to a range of interesting applications. Herein, different fabrication methods from the top‐down approach to the bottom‐up approach and subsequent surface modifications of micro‐/nanostructured interfaces are first introduced. Then, interactions between the surface and liquid, including liquid wetting, liquid transportation, and a number of corresponding models, together with the definition of hydrophilic/hydrophobic, oleophilic/olephobic, the definition and mechanism of superwetting, including superhydrophobicity, superhydrophilicity, and superoleophobicity, are presented. The micro‐/nanostructured interface, with major applications in self‐cleaning, antifogging, anti‐icing, anticorrosion, drag‐reduction, oil–water separation, water collection, droplet (micro)array, and surface‐directed liquid transport, is summarized, and the mechanisms underlying each application are discussed. Finally, the remaining challenges and future perspectives in this area are included.
Fostering Effective Connections Between Academic and Student Affairs at Historically Black Colleges and Universities: From “Career Pathways” to Collaborative Partnerships
Authors: Strayhorn Terrell L.
Published: September 2019

This chapter presents a new model for fostering effective, collaborative partnerships between academic and student affairs at Minority‐Serving Institutions, using an illustrative case study from a historically Black college/university (HBCU) located in Tennessee. After laying the context for collaborations in higher education, the author presents core concepts that may represent an integrated model of collaborative partnerships and describes how it applies to the United Negro College Fund‐funded Career Pathway Initiative at an HBCU.
The Influence of Tribal Colleges and Universities on Native American Student Persistence
Authors: Bryan Rachel
Published: September 2019

This chapter explains how and why Tribal College and University (TCU) enrollment positively influences Native American student persistence in mainstream four‐year institutions. It also explores existing partnerships between TCUs and mainstream four‐year institutions that could help to improve the transfer process, and overall, Native American student persistence. The ways in which academic and student affairs can partner creatively are emphasized throughout.
Online monitoring and diagnosis method of transformer winding deformation
Authors: Wu Hao , Wang Xue , Zhang Jiajia
Published: September 2019

Winding deformation has become an important factor affecting the safe and stable operation of transformers. Parameters such as winding resistance, leakage inductance, and capacitance will change as a result of winding deformation. Therefore, a method of diagnosis of transformer winding deformation based on the above three parameters is proposed in this paper. An equivalent model of the transformer including winding resistance, leakage inductance, and equivalent capacitance is established. Online identification of the winding parameters is realized by the recursive least squares algorithm. Both the winding deformation classification and diagnosis of deformation degree are realized by using the winding parameters identified online. A simulation model of the actual transformer is established for verification and analysis. The results indicate that the method has high precision and overall correct rate. It meets the needs of online monitoring of winding deformation engineering. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Development of driving fatigue strain index using fuzzy logic to analyze risk levels of driving activity
Authors: Ani Mohammad Firdaus , Fukumi Minoru , RahayuKamat Seri , Minhat Mohamad , Husain Kalthom
Published: September 2019

The objective of this study is to develop a driving fatigue strain index using fuzzy logic to analyze the risk levels of driving activity among road users. Driving fatigue is always related to the driving activity and has been identified as one of the vital contributors to the road accidents and fatalities in Malaysia. Therefore, the present article introduces the use of fuzzy logic for the development of strain index to provide the systematic analysis and propose an appropriate solution in minimizing the number of road accidents and fatalities. The development of strain index is based on the six risk factors associated with driving fatigue; muscle activity, heart rate, hand grip pressure force, seat pressure distribution, whole‐body vibration, and driving duration. The data are collected for all the risk factors, and consequently the three conditions or risk levels are defined as ‘safe’, ‘slightly unsafe’, and ‘unsafe’. A membership function is defined for each fuzzy condition. IF‐THEN rules were used to define the input and output variables, which correspond to physical measures. This index is a reliable advisory tool for providing analysis and solutions to driving fatigue problem, which constitutes the first effort toward the minimization of road accidents and fatalities. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Flatulence After Anti‐reflux Treatment (FAART) Study
Authors: Cockbain A. J. , Parameswaran R. , Watson D. I. , Bright T. , Thompson S. K.
Published: September 2019

Background

Flatulence is known to be a common side effect of laparoscopic fundoplication, yet the true incidence is unclear and its impact on patients’ quality of life not well understood. This study aimed to assess the long‐term incidence of flatulence, and its effect on quality of life, following fundoplication.

Methods

All patients who underwent primary laparoscopic fundoplication between 1999 and 2009 were identified from a prospectively maintained institutional database. A cross‐sectional analysis of post‐operative gastrointestinal symptoms and quality of life was performed using a symptom‐specific questionnaire. Statistical analysis of outcomes stratified by sex and type of fundoplication was performed.

Results

462 eligible patients were identified from the database, with follow‐up obtained in 265 (57%). Median age at surgery was 53 (22–78) years. 137 patients (52%) were female. 138 (52%) underwent a 360° fundoplication, the remainder a partial fundoplication. At median follow‐up of 11 (8–15) years, excessive flatulence was reported by 85%. Only 12% reported an adverse impact on social life, and 11% an adverse impact on quality of life. Flatulence was worse following a total than partial fundoplication, women reported more gas‐related symptoms than men, yet neither sex nor wrap type had a significant impact on social life or quality of life.

Conclusions

The majority of patients report excessive flatulence at long‐term follow‐up after anti‐reflux surgery, yet the impact on social life and quality life was small. There was no evidence to support tailoring of wrap type by sex to avoid gas‐related symptoms. The authors advocate that all patients understand the inevitable side effects of fundoplication to help manage expectations from surgery.
Consequences of Moral Transgressions: How Regulatory Focus Orientation Motivates or Hinders Moral Decoupling
Authors: Cowan Kirsten , Yazdanparast Atefeh
Published: September 2019

How can firms mitigate the impact of moral violations on consumer evaluations? This question has pervaded the business ethics literature. Though prior research has identified decoupling as a moral reasoning strategy where consumers separate moral judgments from evaluations (avoiding moral compromise and dissonance), it is unclear what motivates individuals to decouple. It is the objective of this research to explore regulatory focus theory (i.e., a framework examining consumer mindsets as prevention or promotion orientated) as a motivating factor for moral decoupling. Three experiments are undertaken. Study one demonstrates that with a prevention mindset (e.g., analytical thinking) as opposed to promotion mindset (e.g., feeling-based thinking), moral decoupling can be achieved. Specifically, those in a prevention mindset report more favorable evaluations when information about a violation explicitly lowers (vs. does not lower) consequences of moral violations. However, when the violation is related to the business functionality of the brand, those in a prevention (vs. promotion) mindset report less favorable evaluations, except when consequences are lowered. This indicates an inability to decouple (studies 2–3), and results in negative emotions (study 3). The research shows that inability to decouple for those in a prevention mindset leads to negative emotions, lowering evaluations. These results contribute to the moral reasoning literature by linking regulatory focus to decoupling strategies. Further, the research bridges literature on norm activation, moral foundation, regulatory focus, and moral decoupling to reconcile theoretical differences in judgment styles. Implications for businesses and brands are discussed.
Trust Issues and Engaged Buddhism: The Triggers for Skillful Managerial Approaches
Authors: Vu Mai Chi , Tran Trang
Published: September 2019

As a transitional economy, Vietnam has undergone tremendous changes over recent decades within a ‘fusion’ context that blends both traditional and modern values from its complex history. However, few studies have explored how contemporary issues in the context of Vietnam have brought both obstacles and skillful initiatives to managerial approaches to doing business. We draw on the concepts of social trust and institutional theory to explore how informal institutions such as religious forces can contribute to the development of individual trust and whether individuals are willing to extend trust beyond familial networks. We contribute to the notion of a moral conception of trust by exploring how Buddhism in particular has initiated distinctive managerial approaches in the context of Vietnam, in response to dilemmas of social trust. Our findings highlight that as an informal institution, engaged Buddhism yields significant impact on the formation of social trust. We carried out in-depth interviews in Vietnam with 33 organizational leaders who were Buddhist practitioners, using thematic analysis to elucidate our findings and arguments. The study reveals how the incorporation of Buddhist principles has fostered context-sensitive, non-extreme, and reflexive managerial approaches to enhance morality as a response to social trust issues.
Effect of natural fractures on determining closure pressure
Authors: Nadimi S. , Forbes B. , Moore J. , McLennan J. D.
Published: September 2019

In Utah FORGE reservoir, eight pressure transient tests (microhydraulic fracturing and DFIT™) show natural fracture/pressure-dependent leakoff. This behavior may lead to misinterpretation of the closure pressure (proxy for minimum principal stress). The closure pressures obtained from DFIT™ (or microhydraulic fracturing) testing may reflect shear failure along natural fractures or discontinuities rather than tensile failure and lead to inaccurate estimates of the minimum principal stress. In pressure tests conducted at the Utah FORGE site showed that reactivation or opening of natural fractures intersecting the wellbore and were suggested by multiple closure events in DFIT™ tests. In addition, comparisons between the pre- and post-well-tests FMI logs show that there are populations of induced fracture and reactivated natural fractures which are mostly vertical and sub-vertical. In this study, DFIT™ (or microhydraulic fracturing) test analysis and numerical simulations were used to suggest that hydraulic shearing of critically stressed natural fractures can contribute to multiple closure signatures and possibly lead to incorrect determination of the minimum principal stress. As other authors have previously advocated, the DFIT™ test analyses and numerical simulations suggest that better estimations of minimum principal stress may be derived by injecting at relatively high rate and pressure and insuring that tensile breakdown is reached. In addition, extended shut-in period is required to determine accurate reservoir characteristics and fluid flow regime.
Application of variance-based sensitivity analysis in modeling oil well productivity and injectivity
Authors: Ahmed Quosay A. , Nimir Hassan B. , Ayoub Mohammed A. , Mohyaldinn Mysara Eissa
Published: September 2019

Well intervention performed on oil or gas well often involves the injection of different stimulating fluids or chemical solutions that aims to increase the production rate. The main objective of this paper is to identify the effect of uncertainty in different variables and parameters used to quantify well productivity and injectivity. Monte Carlo simulation technique is used to develop probabilistic models for radial Darcy’s inflow on the one hand and near wellbore water-based chemical injection on the other hand. The probabilistic model is based on assigning probability density function for all variables and parameters used in the governing formulas. Variance-based sensitivity analysis (VBSA) was performed to quantify the contribution and the correlation between different model’s inputs and outputs. Results indicate that some rough assumptions for about 60% of injectivity model’s parameters and factors, i.e., value with considerable error/uncertainty, can still result in output with small standard deviation in comparison with other parameters. In Darcy’s law, the uncertainty in reservoir pressure value affects the calculated flow rate two times higher than the effect of the formation of permeability or produced fluid viscosity. At low drawdown condition, about 50% of Darcy’s flow variance is caused by the uncertainty in reservoir pressure input value. Throughout VBSA, it is also found that data accuracy of variables and parameters used in the injectivity model is not of importance as for formation permeability, injected fluid viscosity, pressure, and temperature of the injected fluid. Application of this methodology will focus on the cost of information needed by the decision makers and will save a lot of efforts and resources needed to apply confirmation tests or to validate different data sets.
Graphene Nanostructure-Based Tactile Sensors for Electronic Skin Applications
Authors: Miao Pei , Wang Jian , Zhang Congcong , Sun Mingyuan , Cheng Shanshan , Liu Hong
Published: September 2019

Skin is the largest organ of the human body and can perceive and respond to complex environmental stimulations. Recently, the development of electronic skin (E-skin) for the mimicry of the human sensory system has drawn great attention due to its potential applications in wearable human health monitoring and care systems, advanced robotics, artificial intelligence, and human–machine interfaces. Tactile sense is one of the most important senses of human skin that has attracted special attention. The ability to obtain unique functions using diverse assembly processible methods has rapidly advanced the use of graphene, the most celebrated two-dimensional material, in electronic tactile sensing devices. With a special emphasis on the works achieved since 2016, this review begins with the assembly and modification of graphene materials and then critically and comprehensively summarizes the most advanced material assembly methods, device construction technologies and signal characterization approaches in pressure and strain detection based on graphene and its derivative materials. This review emphasizes on: (1) the underlying working principles of these types of sensors and the unique roles and advantages of graphene materials; (2) state-of-the-art protocols recently developed for high-performance tactile sensing, including representative examples; and (3) perspectives and current challenges for graphene-based tactile sensors in E-skin applications. A summary of these cutting-edge developments intends to provide readers with a deep understanding of the future design of high-quality tactile sensing devices and paves a path for their future commercial applications in the field of E-skin.
Braak neurofibrillary tangle staging prediction from in vivo MRI metrics
Authors: Dallaire‐Théroux Caroline , Beheshti Iman , Potvin Olivier , Dieumegarde Louis , Saikali Stephan , Duchesne Simon ,   National Alzheimer's Coordinating Center,   Alzheimer's Disease Neuroimaging Initiative
Published: September 2019

Introduction

Alzheimer's disease diagnosis requires postmortem visualization of amyloid and tau deposits. As brain atrophy can provide assessment of consequent neurodegeneration, our objective was to predict postmortem neurofibrillary tangles (NFT) from in vivo MRI measurements.

Methods

All participants with neuroimaging and neuropathological data from the Alzheimer's Disease Neuroimaging Initiative, the National Alzheimer's Coordinating Center and the Rush Memory and Aging Project were selected (n = 186). Two hundred and thirty two variables were extracted from last MRI before death using FreeSurfer. Nonparametric correlation analysis and multivariable support vector machine classification were performed to provide a predictive model of Braak NFT staging.

Results

We demonstrated that 59 of our MRI variables, mostly temporal lobe structures, were significantly associated with Braak NFT stages (P< .005). We obtained a 62.4% correct classification rate for discrimination between transentorhinal, limbic, and isocortical groups.

Discussion

Structural neuroimaging may therefore be considered as a potential biomarker for early detection of Alzheimer's disease–associated neurofibrillary degeneration.
Dementia in Aboriginal people in Residential Aged Care Facilities in Alice Springs: A Descriptive Study
Authors: Hocking Bruce , Lowe Michael , Nagel Tricia , Phillips Caroline , Lindeman Melissa , Farthing Annie , Jensen Heather , Cass Alan , Dingwall Kylie
Published: September 2019

Background:

A high prevalence of dementia among Aboriginal and Torres Strait Islanders has been reported but knowledge of underlying causes and associations remains limited.

Objective:

To identify the prevalence of factors that may be associated with the categories of Major neurocognitive disorders (Major NCDs) in Aboriginal people living in residential aged care facilities in Alice Springs in the Northern Territory (NT).

Design and Setting:

This descriptive cross-sectional study analysed clinical file and cognitive assessment data of participants who were identified as having cognitive impairment between January and June 2016.

Method:

Screening for the presence of cognitive impairment using the Kimberley Indigenous Cognitive Assessment (KICA) was undertaken and 58 of 84 Aboriginal people were admitted to the study. Using a clinical file audit, diagnoses of Major NCDs consistent with the DSM-5 classification were made and the prevalence of factors possibly associated with these diagnoses described.

Results:

Fifty of the 58 participants were diagnosed with a Major NCD. The most frequent diagnoses were Major NCD due to vascular disease (30%), Major NCD due to Alzheimer’s Disease (26%) and Major NCD due to brain injury (20%). Hypertension, Type 2 Diabetes Mellitus and alcohol misuse were commonly reported together with hypothyroidism, hypoglycaemia and vitamin D deficiency.

Conclusion(s):

This study identified possible associations with Major NCDs in this population as well as a different spread of Major NCD diagnoses to previous studies in Aboriginal populations. There is a need for further research to understand the causes of dementia in Australian Aboriginal people and to use this information to appropriately tailor treatment and prevention programmes.