bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluate the Performance of Vertical and Horizontal Liquefied Natural Gas Storage Tanks by Using a Non-Equilibrium Resistance-Capacitance Model
Authors: Wang Zhihao , Sharafian Amir , Mérida Walter
Published: January 2020

Methane is the primary component of liquefied natural gas (LNG) and a potent greenhouse gas (GHG). The undesired methane emissions across the natural gas supply chain has been proven to worsen the lifecycle GHG emissions from the transportation sector compared with diesel. Therefore, having accurate fast-response models to predict the performance of natural gas infrastructure, such as LNG storage facilities, becomes crucial to minimize methane emissions. In this study, a novel non-equilibrium multi-species thermodynamic model based on the resistance-capacitance network is developed to assess the thermal performance of LNG storage tanks. The accuracy of the non-equilibrium model is validated against the experimental data of a storage tank under dynamic hot gas injection. Then, the model is employed to analyze the performance of two identical vertical and horizontal storage tanks in a refueling station under self-pressurization condition. The results show that the pressure rise in the stationary vertical and horizontal tanks is similar. However, the temperature gradient between the vapor phase and LNG in the horizontal tank is less than that in the vertical tank due to the larger vapor-liquid interface. This feature allows the horizontal tank to reduce the tank pressure faster than the vertical tank under sudden pressure increase.
The Natural Sit-to-Stand-Walk of the Frail
Authors: Taylor Dorothy , Merryweather Andrew , Morse Janice , Wong Bob
Published: January 2020

Sit-to-stand-walk (STW) is a complex task that sequentially transitions an individual from sitting through standing to walking. In this study we evaluate the unrestricted, natural pattern of movement of the STW task from a hospital bed of 21 (5 Female, 16 Male) frail (MFS > 55) adults (68.0±11.2 years) with a total of 144 unique trials. Bed height (low, medium, high) and bed rail condition (no rails, Hill-Rom®, Stryker®), were varied, generating 9 potential trial types per participant. A new STW phase, Stand Preparation, is defined specifically for the frail that occurs just prior to the Flexion Momentum Phase, also named here as the Stand Initiation Phase. In conjunction with the newly defined Stand Preparation Phase, movements used by the frail to maintain or regain balance during STW task are newly defined as corrective behaviors (CBs). These include hand, foot, leg and torso CBs. In 144 unique STW trials, 678 hand and foot CBs were observed and recorded. The most frequent CB type was the hand CB (335), followed by the foot CB (316). A coding system for use in the kinematic analysis of the natural STW task was developed that identifies CBs through visual observation. In addition, a 3D biomechanical model was generated from collected marker position data and will be used in future biomechanical analyses with the visually observed CB data. The Stand Initiation Phase contained the most CBs. Significant factors included bed height and phase, as well as their interaction (all with p-values ≤ 0.006). This is the first study to establish a more accurate and complete STW of the frail elderly, as well as to define CBs employed during their natural STW. The dataset from this coding system, along with the newly established STW phases of the frail, are currently being used for further analyses to determine the exact timing and position of fall initiations during STW of the frail.
An Approach to Bringing Automated Fault Detection and Diagnosis (AFDD) Tools for HVAC&R Into the Mainstream
Authors: Hacker Annika , Gorthala Ravi , Thompson Amy
Published: January 2020

Heating, ventilation and air-conditioning (HVAC) systems can consume over 5 quads of energy annually, representing 30% of energy consumption in the U.S. in commercial buildings. Additionally, commercial refrigeration (R) systems add about 2 quads to commercial buildings energy consumption. Most HVAC systems have one or more faults (low/high refrigerant charge, valve leakage, condenser/evaporator fouling, filter/dryer restriction, economizer faults, controls faults) that result in increased energy consumption. Automated fault detection and diagnosis (AFDD) tools have been developed to address this national issue and many tools are commercially available. AFDD tools have the potential to save considerable energy for existing commercial RTUs, chillers and refrigeration systems. These devices can be used for both retro commissioning, and, when faults are addressed, continuous commissioning as well. However, there appears to be multiple market barriers for this technology. A key market barrier for this technology is the lack of awareness of AFDD products among potential customers. Most HVAC contractors are not familiar with the latest AFDD technologies and HVAC technicians lack skills regarding these technologies. Quantifying potential benefits to building owners is difficult since there are several FDD tools with varying capabilities. For instance, there are several FDD products ranging from handling just economizer faults to those that also handle full-blown refrigerant-side and air-side faults. Methods/algorithms used in FDD vary significantly. Even though there are efforts to develop standards, currently there are no standards/methods to define functions, capabilities, accuracy, and reliability of FDD tools. Moreover, most of the commercial AFDD tools have not been verified in the field independently. This paper presents a comprehensive approach to bringing HVAC AFDD tools into the mainstream. The approach involves demonstrating ten commercially available tools at ten different sites, independent testing and evaluation of the FDD tools, communication with various stakeholders, identifying market barriers, and assisting utility companies in developing incentive programs. This paper presents selection of AFDD tools, site identification, and field testing and evaluation method.
Controlling Evaporation Induced Self-Assembly of Polymeric Nanoparticles: A VOF-DPD Study
Authors: Tayeb Raihan , Zhang Yuwen
Published: January 2020

A mesoscopic simulation method combining multiphase Volume of Fluid (VOF) method and Dissipative Particle Dynamics (DPD) is employed to investigate and control self-assembly of charged polymeric nanoparticles in microdroplet solution deposited on plane substrate during solvent evaporation. A droplet evaporation model is first developed and validated. A coupling scheme between the CFD and the DPD simulation for particles is then presented. The DPD simulation includes the DLVO forces between the particles, their interaction with the substrate surface, Stokes drag, Brownian, and capillary forces. Numerical results show qualitative agreement with available experimental results. The proposed simulation method is expected to provide valuable tools for controlling and optimizing self-assembly of nanoparticles.
Finite Element Microstructural Analysis of Thermal Damage in High Volume Fraction RVE of Particle-Reinforced Refractory Composites
Authors: Makarian Kamran , Santhanam Sridhar
Published: January 2020

Previously, we experimentally studied high-temperature behavior of three types of castable particle-reinforced ceramic composites that we designed for application in aerospace industry. These composites contain Zirconia particles (ZrO2) and bubbles, and silicon-carbide (SiC) particles as reinforcements, dispersed in an alumina (Al2O3) matrix. The present work aims to implement a Finite Element (FE) damage mechanics modeling approach based on the experimental results to investigate micro-scale mechanisms of failure in these materials and ascertain the effect of particle size and volume fraction (VF). Different mechanisms of failure are detected for different types of inclusions, and the percentage of yielded elements seem to strongly correlate with the theoretical thermal shock indices. Additionally, within the limits of this study, VF showed to have a positive correlation with the percentage of yielded elements, whereas inclusion size depicted an inverse correlation to that parameter. These novel findings shed new light on the micro-scale mechanisms of thermal failure in ceramic composites with complex microstructures.
A Feasibility Study of Wind Farm Yaw Angle Optimization
Authors: Kuo Jim , Li Ni , Shen He
Published: January 2020

Wind farm energy production optimization has received significant attention in recent years. Much of this effort had been focused on optimizing positions of wind turbines within a wind farm domain during the design and planning stage. Optimization of wind turbine positions can reduce wake interactions of upstream turbines. In addition to optimizing turbine positions to reduce wake interactions, prior studies have shown that optimizing yaw and pitch angles can improve energy production as upstream wakes yaw away from downstream turbines. However, yaw angle optimization at the wind farm level has been difficult due to lack of low-fidelity wake model for simulating yawed wakes. Recently, an analytical wake model capable of simulating yawed turbine wakes had been developed, which enable wind farm-scale yaw optimization. In this work, a binary quadratic programming model problem formulation has been developed to optimize yaw angles of wind farms. Yaw optimization of two position-optimized layouts available in the literature were performed to study the potential of yaw optimization. In particular, we set out to understand how layout and wind farm density affect yaw optimization potential. An optimized layout of 39 turbines with 40m rotor diameter in a 2km by 2km domain was used in this study. For this wind farm, yawing optimization only improved power production by ∼1.5% under favorable wind directions. However, as wind farm power density increases by increasing rotor diameter to 60m and 80m, power production improved by ∼5% and ∼10% respectively, under favorable wind directions. Finally, another yaw optimization was performed on an optimized layout with 48 turbines of 82m rotor diameter in a 4km by 4km domain using the proposed model formulation. Under favorable wind directions, yaw angle optimization improved performance by ∼4%. The results show that yaw optimization can improve power production in the same order of magnitude as layout optimization, and that it should be considered in addition and/or in tandem to layout optimization.
Autonomous Detection of PV Panels Using a Drone
Authors: Ismail Hesham , Chikte Rufaidah , Bandyopadhyay Akash , Al Jasmi Nawal
Published: January 2020

In recent years, there has been a lot of interest in clean energy especially in solar energy leading to the construction of numerous photovoltaic (PV) panels around the world. These panels need to be inspected to make sure they produce the desired amount of electricity. There are many methods to inspect which are manual, semi-autonomous and fully autonomous. The manual and semi-autonomous already exist but the process is tedious and requires a lot of time and resources. In this paper, we propose a fully autonomous solution where the drone will be preprogrammed to follow certain waypoints inputted via GPS data. The drone is equipped with a thermal camera where the video is recorded for postprocessing. The video is processed offline in order to detect the panels using image processing techniques such as thresholding, binary, canny edge, hough transform, and others. The novelty of this paper is on proposing a fully integrated solution for PV panel detection using a drone; it paves a way for future applications involving machine and deep learning.
Retracted: “Insights Into the Mechanical Properties of Bi-Layer Germanene Coupled by Covalent Bonding” [ASME 2019 International Mechanical Engineering Congress and Exposition, Volume 10: Micro- and Nano-Systems Engineering and Packaging, Salt Lake City, Utah, USA, November 11–14, 2019, Conference Sponsors: ASME, ISBN: 978-0-7918-5947-6, Copyright © 2019 by ASME. Paper No. IMECE2019-12129, pp. V010T12A023; 8 pages; doi: 10.1115/IMECE2019-12129]
Authors: ASME
Published: January 2020

The above referenced paper has been removed from publication. (March 11, 2020)

Copyright © 2020 by ASME
An Experimental Approach in Defect Detection of a Single Row Ball Bearing Using Noise Generation Signal
Authors: Afsharfard Aref , Sanei Seyed Hamid Reza
Published: January 2020

Bearings are critical mechanical components that are used in rotary machinery. Timely detection of defects in such components can prevent catastrophic failure. Noise is generated during the rotation of bearings even without the presence of defects due to finite number of rotating elements to carry the load. Such noise is associated with the change in effective stiffness during rotation, however, a sharp spike is observed in the noise level with presence of local defects. This study uses the noise generation aspect of roller bearings to identify local defect in a single row ball bearing with outer race stationary under radial load. Experimental testing is conducted on two identical bearings. The defective bearing is selected from a diesel engine subjected to 20 years of service. Dissecting the defective bearing revealed pitting and spalling of the inner race and balls, the most two common bearing defects. Both time and frequency analysis of sound pressure generated by the bearings were performed. The results show that there is a clear distinction in the time and frequency spectra between healthy and defective bearings. Findings of this study revealed that using a simple cost efficient in-house experimental setup, local defects can be readily detected.
Computer Aided Methodology for the Optimization of an Electric Motorcycle Suspension
Authors: Pabón Villamizar Dany , Roa Prada Sebastián
Published: January 2020

There are almost 9 million motorcycles registered only in the United States, while in other much smaller countries such as Colombia, this number can exceed 8 million. However, the population of Colombia is about six times smaller than the population in the United States. This demonstrates that for many people around the world, motorcycles are a great transportation method, which at the same time can provide a solution to the problems of urban traffic and scarcity of parking space. In addition to the problems associated with traffic, there are also public health problems related to the air pollution generated by internal combustion engines in motor vehicles. The issue of greenhouse gases emission from motor vehicles is being tackled by electric propulsion systems. The massive use of electric vehicles can have a strong positive impact in the quality of life of people and the environment. Therefore, electric motorcycles can become an optimal solution for transportation, by reducing the problems of urban traffic and space, while also being friendly with the environment. Two ways to help popularizing these vehicles are by reducing their cost and improving their performance. This work focuses on the optimization of the suspension system which is one of the key components of a motorcycle. The main function of the suspension system is to provide safety and comfort to the riders, two conditions that must be guaranteed in a good design. This article proposes a methodology for the optimal design of a motorcycle suspension, considering the different phases of development, starting with the geometric design, where the different parameters are determined for the front suspension, such as Rake Angle and Trail, and for the rear suspension, such as the inclination and the geometry of the swing arm system. Next, the detailed design is carried out, making sure that the elements of the suspension coincide with the dimensions at the attachment points to the chassis. Once all the geometry is available, the kinematic analysis is carried out, to assess the behavior of the system during the wheel trip. A structural analysis is performed to evaluate stresses, stiffness and resonance frequencies of the system, and to evaluate the minimum safety factor of the structure under the action of typical loads. With the final geometry of the system, a lumped parameter model can be obtained to rapidly observe its transient behavior under the effect of different irregularities that may be encountered on the road, which lead to the optimization of the parameters that offer greatest comfort to the rider. This set of parameters was used as inputs for the representation of the system in the physical modeling simulation interface Simmechanics® to generate final performance graphs. The results obtained with this methodology covered the different aspects that must be considered in the design of an important part of a transportation system such as an electric motorcycle.
Computational Simulation and Analysis of Major Control Parameters of Time-Dependent PV/T Collectors
Authors: Shi Jimeng , Lin Cheng-Xian
Published: January 2020

In order to improve performance of photovoltaic/thermal (or PV/T for simplicity) collectors, this paper firstly validated a previous computational thermal model and then introduced an improved computational thermal model to investigate the effects of the major control parameters on the thermal performance of PV/T collectors, including solar cell temperature, back surface temperature, and outlet water temperature. Besides, a computational electrical model of PV/T system was also introduced to elaborate the relationship of voltage, current and power of a PV module (MSX60 poly-crystalline solar cell) used in an experiment in the literature. Simulation results agree with the experimental data very well. The effects of the time-steps from 1 hour to minute, which is closed to the real time, were also reported. At last, several suggestions to improve the efficiency of PV/T system were illustrated.
Analysis of Flow Through Packed Bed of Spheres Containing Phase Change Materials for Thermal Energy Storage Applications
Authors: Prabhu Vinit V. , Languri Ethan , Nawaz Kashif
Published: January 2020

The research on thermal energy storage (TES) systems have received a lot of attention in recent decades for sustainable use of thermal energy in various industrial and residential applications. The existing challenge in designing the TES is the response time of charging and discharging cycles that keeps these systems away from wide utilization in industries. Literature data show that beside the low thermal conductivity of most phase change materials (PCMs) as active media in TES systems, the poor flow distribution may be another factor affecting the response rate. This study aims to considerably reduce the response time by packing the PCMs in a bed of spheres made of high thermal conductivity material. The response rate during the charging cycle is studied numerically by passing hot water at 70 °C over the packed bed of spheres. The numerical analysis is performed using ANSYS Fluent 19. The PCM used in this study is a paraffin and has a melting point of 48 °C. The response rate of the system is studied and it is compared to other similar systems mentioned in literature. The amount of energy storage is also studied by changing the flow rate of water.
Investigation of Cyclic and Frequency Nanoindentation Effects in Polydimethylsiloxane
Authors: Patel Hinal , Yang Chen , Lee Howon , Pelegri Assimina A.
Published: January 2020

The nanoindentation response of polydimethylsiloxane (PDMS) is examined using single nanoindentation loading and small-scale fatigue. It is well known that viscoelastic material response is inherently related to the local loading and environmental conditions. First, quasistatic nanoindentation experiments were performed at various depths through the specimen to benchmark our nanoindentation results with literature data. The PDMS cyclic and frequency dependence to quasi-static and dynamic nanoindentation loading was studied and a ‘load/partial-unload’ technique was employed to investigate nanoindentation modulus variation through the thickness of the specimen. The frequencies of the small-scale fatigue tests were varied to study periodic response. The average indentation modulus for PDMS at 2mN load-controlled tests was 4.37 ± 0.1 MPa. The PDMS sample had an average indentation modulus value of 3.94 ± 0.06 MPa for 3mN load-controlled tests. The indentation moduli decreased as the maximum depth increased because the stiffness reduced when indentations were performed further from the surface. The single nanoindentation data was confirmed with literature values and validated the precision of nanoindentation testing.

Small-scale fatigue tests were implemented at 50 cycles with frequencies of 1, 0.5, and 0.033 Hz. The lower frequencies displayed an increase in maximum depth at a given controlled load due to relaxation and creep effects. As with the single nanoindentations, the small-scale fatigue tests confirmed the decreasing trend of indentation moduli as the maximum depth increased. Overall, the two nanoindentation methods corroborated similar trends in changes of the PDMS mechanical response.
Additive Manufacturing of Kevlar Reinforced Epoxy Composites
Authors: Nawafleh Nashat , Chabot Jordan , Aljaghtham Mutabe , Oztan Cagri , Dauer Edward , Gorguluarslan Recep M. , Demir Teyfik , Celik Emrah
Published: January 2020

Additive manufacturing is defined as layer-by-layer deposition of materials on a surface to fabricate 3D objects with reduction in waste, unlike subtractive manufacturing processes. Short, flexible Kevlar fibers have been used in numerous studies to alter mechanical performance of structural components but never investigated within printed thermoset composites. This study investigates the effects of adding short Kevlar fibers on mechanical performance of epoxy thermoset composites and demonstrates that the addition of Kevlar by 5% in weight significantly improves flexure strength, flexural modulus, and failure strain by approximately 49%, 19%, and 38%, respectively. Hierarchical microstructures were imaged using scanning electron microscopy to observe the artefacts such as porosity, infill and material interdiffusion, which are inherent drawbacks of the 3D printing process.
Nonlinear Dynamic Analysis of an Asymmetric Ball Bearing Rotor System
Authors: Bahan Doğancan , Ciğeroğlu Ender
Published: January 2020

Performance of ball bearing–rotor systems are highly dependent on and often limited by characteristics of ball bearings. Several studies are available in the literature, investigating varying compliance and subharmonic resonances of ball bearings. Most of the studies are carried out with rigid rotors to focus on modelling of the bearings. There exist few studies which take flexibility of rotors into account. Furthermore, even if the rotor flexibility is modelled, most of the time symmetrical rotors are considered. However, rotors are rarely symmetric in realistic applications due to different locations of bearings and different weights of rotor components (compressors, turbines etc.). In this study, an asymmetric, balanced, flexible rotor supported by ball bearings considering Hertzian contact and radial clearance is investigated. Rotor shaft is modelled with Nelson finite rotor elements using Timoshenko beam theory and disks are considered as rigid masses. Harmonic Balance Method (HBM) is used to obtain nonlinear algebraic equations in the frequency domain and Alternating Frequency Time (AFT) method is utilized to find Fourier coefficients of nonlinear bearing forces. In order to decrease the number of nonlinear equations to be solved, Receptance Method (RM) is applied. Resulting set of nonlinear algebraic equations is solved by using Newton’s method with arclength continuation. Several case studies are performed and effects of asymmetry on nonlinear periodic vibration response of rotors are studied.
Study of Metallurgical and Mechanical Behavior of Laser Butt-Welded Dissimilar Joint of Inconel and Stainless Steel
Authors: Jaypuria Sanjib , Gupta Santosh Kumar , Suresh-Fazeela Sulthan , Pratihar Dilip Kumar , Chakrabarti Debalay , Jha M. N.
Published: January 2020

High energy density welding processes like laser and electron beam welding are capable of welding dissimilar plates with much ease due to high power density and low heat input in spite of the varying thermos-physical properties of the used alloys. The present work is aimed to check the feasibility of joint prepared with laser welding of SS 316L and Inconel 718 plates. The experiments are designed to study the effect of welding speed on the mechanical and metallurgical behavior of the joints without any offset to joint line. The formation of laves phases is confirmed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) phase analysis. These laves phase are micro-segregation of Nb, Fe, C and Cr, which is because of high temperature in a small area of fusion zone (FZ) due to intense heat of laser source. Micro-segregation of different elements has led to micro-fissures, which is detrimental for the joints operating at elevated temperature. Cooling rate and peak temperature during welding play the significant role in obtaining a sound quality joint. The present work gives an insight on feasibility of laser welded joint of SS 316L and Inconel 718 with suitable selection of welding speed during laser welding.
Thermoelectric Generator-Based System for Energizing Low-Power Communication and Geolocation Electronics
Authors: Eldaly Mamdouh , Pokharel Ashish , Petralia Michael , Unnthorsson Runar , Dell Robert
Published: January 2020

A small-scale thermoelectric generator (TEG) system produces a power of 1.43 W at a temperature differential between the thermoelectric module (TEM) surfaces of 70.00°C. This can cold-start a GSM locator and broadcast coordinates using an SMS message. Ultra-low power off-the-shelf electronics are combined to produce a reliable cellular signal and generate the coordinates, eliminating the need for dedicated GPS modules and reducing the total power consumption. A supercapacitor-based charging system was designed to store charge from the TEMs and discharge a constant 5.2 V to power the electronics. The system requires approximately 60 seconds from a cold start to send geographic coordinates. Designs for several cold blocks, used to generate the temperature differential for the TEMs, were investigated, including designs utilizing phase-change material (PCM) and water.
Design, Analysis and Test of Multi-Stage Crashworthiness Energy Absorbing Device for Railway Vehicles
Authors: Hong Haifeng , Liu Hongtao , Fang Ziwen , Wang Kefei , Wang Jianran , Luo Qi
Published: January 2020

An anti-collision and energy absorbing device is generally placed at the front end of railway vehicles to provide controlled collapse and sufficient energy absorbing capacity. In the conventional way, the energy absorbing device is usually designed as an integrated part of the carbody that can’t be easily replaced nor maintained after crash. To increase the maintainability and energy absorbing capacity of the energy absorbing device, a Multi-stage Crashworthiness Energy Absorbing Device has been developed, in which the first-stage and the second-stage energy absorbing units can be replaced or repaired under the collision that is not severe enough to initiate the third-stage energy absorbing unit. The Crashworthiness Energy Management (CEM) has four stages: coupler energy absorbing components (stage 1), honeycomb in the sliding center anti-climber (stage 2), metal peeling tubes mounted at the back of the fixed anti-climber (stage 3) and the structural components in the cab area (stage 4). By comparing the simulation results and test results, it is concluded that the finite element simulation model can provide dependable and accurate prediction for collision behaviors. Based on the design, simulation and test data, a safe, reliable and maintainable Multi-stage Crashworthiness Energy Absorbing Device has been verified and validated, which can provide valuable reference for researchers and engineers in the crashworthiness and railway vehicle industry.
In situ x-ray photoelectron spectroscopy study of lithium carbonate removal from garnet-type solid-state electrolyte using ultra high vacuum techniques
Authors: Jones Jessica C. , Rajendran Sathish , Pilli Aparna , Lee Veronica , Chugh Natasha , Arava Leela Mohana Reddy , Kelber Jeffry A.
Published: January 2020

Solid-state electrolytes (SSEs) are of significant interest for their promise as lithium ion conducting materials but are prone to degradation due to lithium carbonate formation on the surface upon exposure to atmosphere, adversely impacting Li ion conduction. In situ x-ray photoelectron spectroscopy monitored changes in the composition of the SSE Li garnet [Li6.5La3Zr1.5Ta0.5O12 (LLZTaO)] upon annealing in ultrahigh vacuum (UHV) and upon Ar+ ion sputtering. Trends in core level spectra demonstrate that binding energy (BE) calibration of the Li 1s at 56.4 eV yields a more consistent interpretation of results than the more commonly used standard of the adventitious C 1s at 284.8 eV. Annealing one ambient-exposed sample to >1000 K in UHV effectively reduced surface carbonate and oxygen, leaving significant amounts of carbon in lower oxidation states. A second ambient-exposed sample was subjected to 3 keV Ar+ ion sputtering at 500 K in UHV, which eliminated all surface carbon and reduced the O 1s intensity and BE. These methods present alternative approaches to lithium carbonate removal than heating or polishing in inert atmospheres and are compatible with fundamental surface science studies. In particular, the data show that sputtering at mildly elevated temperatures yields facile elimination of carbonate and other forms of surface carbon. This is in contrast to annealing in either UHV or noble gas environments, which result in carbonate reduction, but with significant remnant coverages of other forms of carbon.
Ganong effects for frequency may not be robust
Authors: Politzer-Ahles Stephen , Lee Ka Keung , Shen Lue
Published: January 2020

The Ganong effect—more identifications of a certain phoneme in a context where that phoneme would yield a real word than a context where that phoneme would yield a pseudoword—has been widely replicated. Few studies, however, have tested whether this effect occurs for frequency contrasts. In the present study, participants' likelihood of identifying an ambiguous sound as aspirated was tested in acoustically identical continua in contexts where the identification of the sound as aspirated would either yield a lower- or higher-frequency word than the identification of the sound as unaspirated would. No frequency-based Ganong effect was found.
REVIEWS OF ACOUSTICAL PATENTS
Authors: Fulop Sean A.
Published: January 2020

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website, and also using Google Patents.
Numerical modeling of submicron particles for acoustic concentration in gaseous flow
Authors: Liu Jizhou , Li Xiaodong , Hu Fang Q.
Published: January 2020

This paper intends to explore the rationality and feasibility of modeling dispersed submicron particles in air by a kinetic-based method called the unified gas-kinetic scheme (UGKS) and apply it to the simulation of particle concentration under a transverse standing wave. A gas-particle coupling scheme is proposed where the gas phase is modeled by the two-dimensional linearized Euler equations (LEE) and, through the analogous behavior between the rarefied gas molecules and the air-suspended particles, a modified UGKS is adopted to estimate the particle dynamics. The Stokes' drag force and the acoustic radiation force applied on particles are accounted for by introducing a velocity-dependent acceleration term in the UGKS formulation. To validate this methodology, the computed concentration patterns are compared with experimental results in the literature. The comparison shows that the adopted LEE-UGKS coupling scheme could well capture the concentration pattern of suspended submicron particles in a channel. In addition, numerical simulations with varying standing wave amplitudes, different acoustic radiation force to drag force ratios, and mean flow velocities are conducted. Their respective influences on the particle concentration pattern and efficiency are analyzed.
Candida auris Biofilm Colonization on Skin Niche Conditions
Authors: Uppuluri Priya
Published: January 2020

Candida auris
, an emerging multidrug-resistant yeast, has recently been associated with outbreaks of invasive infections in health care facilities worldwide. Its success as a nosocomial pathogen lies in its capability to sustain for prolonged periods in the intensive care unit (ICU), adeptly colonize skin, and spread among patients. Little is known of the mechanism behind the predilection of
C. auris
for skin or the extent of its resilience on it. Now, M. V. Horton, C. J. Johnson, J. F.
Transient seizure-induced sodium increase camouflaging a symptomatic hyponatremia
Authors: de Leeuw David Christian , Kooter Albertus Jozef
Published: January 2020

Hyponatremia is the most commonly observed electrolyte disturbance in clinical medicine. Occasionally the initial presentation of a patient with a symptomatic hyponatremia is a seizure or coma. This life-threatening complication needs early diagnosis and immediate treatment. Here, we report a case of a 27-year-old man who presented with an epileptic seizure, lactate acidosis and sulcal effacement on CT in which a transient sodium increase masked a clinically relevant hyponatremia thereby delaying diagnosis. This phenomenon is caused by an extracellular water shift and can occur when blood analysis is performed shortly after vigorous exercise or a seizure. This case provides awareness for a less well-known cause of plasma sodium increase and offers recommendations to prevent misinterpretation and help clinicians in decision making.
Does intensive glycaemic control promote healing in diabetic foot ulcers? – a feasibility study
Authors: Dissanayake Ajith , Vandal Alain C , Boyle Veronica , Park Diane , Milne Bobbie , Grech Roger , Ng Anthony
Published: January 2020

Introduction

One in four diabetes patients will develop a foot ulcer over their lifetime. The role of glycaemic control in the healing of foot ulcers in diabetes patients is not supported by randomised controlled trial (RCT) data.

Objectives

To determine the feasibility of an RCT of glycaemic control with intensive insulin therapy in diabetic foot ulcer, by assessing: entry criteria, fasting capillary blood glucose (FCBG) medication satisfaction and sensitivity of different ulcer-healing endpoints to glycaemic control.

Design

Two substudies: one cross-sectional and one single-arm prospective.

Setting

Single-centre secondary care diabetic foot clinic in New Zealand.

Participants

Substudy 1: 78 participants consisting of all people ≥18 years with a diabetic foot ulcer presenting to the clinic over 35 weeks in 2015.

Substudy 2: 15 participants from Substudy 1 consenting to intensive insulin therapy.

Intervention

Substudy 1: None.

Substudy 2: Intensive insulin therapy with standard podiatry care over 24 weeks.

Outcome

Substudy 1: Proportion of participants satisfying potential RCT entry criteria; medication satisfaction (Diabetes Medication Satisfaction).

Substudy 2: FCBG, index ulcer healing time, index ulcer size, health-related quality of life (HRQoL; EuroQol 5 Dimensions 5 Levels and Diabetic Foot Ulcer Scale-Short Form).

Results

Proportion in Substudy 1 satisfying all entry criteria was 31% (95% CI 21 to 42). FCBG values decreased between baseline and study end (difference −3.7 mmol/L, 95% CI −6.5 to −0.8); 83% (95% CI 44 to 95) of ulcers healed by 24 weeks. FCBG correlated negatively with medication satisfaction. Ulcer area logarithm was most sensitive to FCBG changes, displaying significant negative correlation with HRQoL outcomes. Detecting a 30% between-group difference in this outcome (80% power, α=5%) requires 220 participants per arm, achievable within 1 year with 15 centres similar to study setting.

Conclusions

An adequately powered RCT requires cooperation between a large number of centres. Ulcer area logarithm should be primary endpoint.

Trial registration number

ANZCTR ACTRN12617001414303
Impact and use of reviews and ‘overviews of reviews’ to inform clinical practice guideline recommendations: protocol for a methods study
Authors: Lunny Carole , Ramasubbu Cynthia , Gerrish Savannah , Liu Tracy , Salzwedel Douglas M , Puil Lorri , Mintzes Barbara , Wright James (Jim)
Published: January 2020

Introduction

Guidelines are systematically developed recommendations to assist practitioner and patient decisions about treatments for clinical conditions. High quality and comprehensive systematic reviews and ‘overviews of systematic reviews’ (overviews) represent the best available evidence. Many guideline developers, such as the WHO and the Australian National Health and Medical Research Council, recommend the use of these research syntheses to underpin guideline recommendations. We aim to evaluate the impact and use of systematic reviews with and without pairwise meta-analysis or network meta-analyses (NMAs) and overviews in clinical practice guideline (CPG) recommendations.

Methods and analysis

CPGs will be retrieved from Turning Research Into Practice and Epistemonikos (2017–2018). The retrieved citations will be sorted randomly and then screened sequentially by two independent reviewers until 50 CPGs have been identified. We will include CPGs that provide at least two explicit recommendations for the management of any clinical condition. We will assess whether reviews or overviews were cited in a recommendation as part of the development process for guidelines. Data extraction will be done independently by two authors and compared. We will assess the risk of bias by examining how each guideline developed clinical recommendations. We will calculate the number and frequency of citations of reviews with or without pairwise meta-analysis, reviews with NMAs and overviews, and whether they were systematically or non-systematically developed. Results will be described, tabulated and categorised based on review type (reviews or overviews). CPGs reporting the use of the Grading of Recommendations, Assessment, Development and Evaluation approach will be compared with those using a different system, and pharmacological versus non-pharmacological CPGs will be compared.

Ethics and dissemination

No ethics approval is required. We will present at the Cochrane Colloquium and the Guidelines International Network conference.
Vitamin D supplementation to improve pregnancy and perinatal outcomes: an overview of 42 systematic reviews
Authors: Bialy Liza , Fenton Tanis , Shulhan-Kilroy Jocelyn , Johnson David W , McNeil Deborah A , Hartling Lisa
Published: January 2020

Objective

To review the evidence to assess effectiveness of vitamin D supplementation during pregnancy and associations of serum vitamin D levels with perinatal outcomes.

Design

Overview of systematic reviews (SRs).

Data sources

Searches conducted in January 2019: Ovid Medline (1946–), Cochrane Library databases.

Eligibility criteria for selecting studies

Two reviewers independently screened titles and abstracts, and full texts using predefined inclusion criteria: SRs evaluating vitamin D supplementation in pregnant women and/or examining the association between serum vitamin D levels reporting at least one predefined perinatal outcome. Only SRs with high AMSTAR scores were analysed.

Data extraction and synthesis

Data were extracted independently by one reviewer and checked by a second. Results were assessed for quality independently by two reviewers using GRADE criteria.

Results

Thirteen SRs were included, synthesising evidence from 204 unique primary studies. SRs of randomised controlled trials (RCTs) with the highest level of evidence showed no significant benefit from vitamin D in terms of preterm birth (RR 1.00 (95% CI 0.77, 1.30); high quality), pre-eclampsia (RR 0.91 (0.45, 1.86); low quality), gestational diabetes (RR 0.65 (0.39, 1.08); very low quality), stillbirth (RR 0.75 (0.50, 1.12); high quality), low birth weight (RR 0.74 (0.47, 1.16); low quality), caesarean section (RR 1.02 (0.93, 1.12); high quality). A significant difference was found for small for gestational age (RR 0.72 (0.52, 0.99); low quality). SRs of observational studies showed associations between vitamin D levels and preterm birth (RR 1.19 (1.08, 1.31); moderate quality), pre-eclampsia (RR 1.57 (1.21, 2.03) for 25-hydroxy vitamin D (25 (OH)D)<50 nmol/L subgroup; low quality), gestational diabetes (RR 1.12 (1.02, 1.22) for 25 (OH)D<50 nmol/L and RR 1.09 (1.03, 1.15)<75 nmol/L; moderate quality) and small for gestational age (RR 1.35 (1.18, 1.54)<50 nmol/L; low quality). SRs showed mixed results for associations between vitamin D and low birth weight (very low quality) and caesarean section (very low quality).

Conclusion

There is some evidence from SRs of observational studies for associations between vitamin D serum levels and some outcomes; however SRs examining effectiveness from RCTs showed no effect of vitamin D supplementation in pregnancy with the exception of one predefined outcome, which had low quality evidence. Credibility of the evidence in this field is compromised by study limitations (in particular, the possibility of confounding among observational studies), inconsistency, imprecision and potential for reporting and publication biases.
Educational differentials in key domains of physical activity by ethnicity, age and sex: a cross-sectional study of over 40 000 participants in the UK household longitudinal study (2013–2015)
Authors: Fluharty Meg E , Pinto Pereira Snehal M , Benzeval Michaela , Hamer Mark , Jefferis Barbara , Griffiths Lucy J , Cooper Rachel , Bann David
Published: January 2020

Objectives

To assess whether educational differentials in three key physical activity (PA) domains vary by age, sex and ethnicity.

Design

National cross-sectional survey.

Setting

UK.

Participants

Altogether 40 270 participants, aged 20 years and over, from the UK Household Longitudinal Study with information on education, PA and demographics collected in 2013–2015.

Outcome measures

Participation in active travel (AT), occupational activity (OA) and leisure time physical activity (LTPA) at the time of assessment.

Results

Lower educational attainment was associated with higher AT and OA, but lower weekly LTPA activity; these associations were modified by sex, ethnicity and age. Education-related differences in AT were larger for women—the difference in predicted probability of activity between the highest and the lowest education groups was −10% in women (95% CI: −11.9% to 7.9%) and −3% in men (−4.8% to –0.4%). Education-related differences in OA were larger among men −35% (-36.9% to –32.4%) than women −17% (-19.4% to –15.0%). Finally, education-related differences in moderate-to-vigorous LTPA varied by ethnicity; for example, differences were 17% (16.2% to 18.7%) for white individuals compared with 6% (0.6% to 11.6%) for black individuals.

Conclusions

Educational differences in PA vary by domain and are modified by age, sex and ethnicity. A better understanding of physically inactive subgroups may aid development of interventions to both increase activity levels and reduce health inequalities.
Suicidal behaviours and moderator support in online health communities: protocol for a scoping review
Authors: Perry Amanda , Lamont-Mills Andrea , du Plessis Carol , du Preez Jan , Pyle Denise
Published: January 2020

Introduction

Suicidal ideation and suicidal behaviours are common yet complex mental health presentations that can pose significant challenges for health professionals. The inability to accurately predict the individuals who may move from experiencing suicidal ideation and associated behaviours, to completing suicide, presents one such challenge. This can make it difficult to provide interventions and support to those most in need. Online health communities are one possible source of support for individuals who experience suicidal ideation and behaviours. These communities are becoming an increasingly popular way of accessing support, often with life-saving consequences. Within online communities, support is offered by various individuals including, in some instances, health professionals from various backgrounds, who work as online health community moderators. Given the growth of online communities and the increasing number of health professionals working as moderators, this scoping review seeks to map the literature that has focused on health professionals working as online community moderators, who interact with members experiencing suicidal ideation and behaviours. Mapping the existing literature offers benefits to both research and practice by identifying gaps in the research and providing a beginning knowledge base of current practice that can inform the training and development of health professionals working as community moderators.

Methods and analysis

This scoping review will follow the methodological framework of Arksey and O’Malley, later adapted by Levacet al. To ensure appropriate rigour, this protocol uses the 20-item Preferred Reporting Items for Systematic Reviews and Meta-Analyses and extension for Scoping Reviews. Literature will be identified using a search strategy developed in consultation with a specialist research librarian at the university where the researchers are employed. Ten multidisciplinary databases will be independently searched by two researchers, and both researchers will screen for inclusion, and undertake the data extraction. The first author will perform a quality assessment of the articles that are selected for inclusion. A second researcher will complete a random audit of 20% of the included articles to assess for quality and suitability in answering the research questions. The first author will complete the analysis and synthesis of the data. A numerical and narrative synthesis of the included studies will be provided.

Ethics and dissemination

The scoping review has been deemed as being exempt from ethical review as no data will be collected from human participants. The results of the scoping review may be published in a peer-reviewed journal, thesis, presented at relevant conferences, and shared with relevant knowledge users.