bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finite Volume-Based Asymptotic Homogenization of Periodic Materials Under In-Plane Loading
Authors: He Zhelong , Pindera Marek-Jerzy 
Published: August 2020

AbstractThe previously developed finite volume-based asymptotic homogenization theory (FVBAHT) for anti-plane shear loading (He, Z., and Pindera, M.-J., “Finite-Volume Based Asymptotic Homogenization Theory for Periodic Materials Under Anti-Plane Shear,” Eur. J. Mech. A Solids (in revision)) is further extended to in-plane loading of unidirectional fiber reinforced periodic structures. Like the anti-plane FVBAHT, the present extension builds upon the previously developed finite volume direct averaging micromechanics theory applicable under uniform strain fields and further accounts for strain gradients and non-vanishing microstructural scale relative to structural dimensions, albeit with multidimensional in-plane loadings incorporated. The unit cell problems at different orders of the asymptotic field expansion are solved by satisfying local equilibrium equations and displacement and traction continuity in a surface-averaged sense which is unique among the existing asymptotic homogenization schemes, leading to microfluctuation functions that yield homogenized stiffness tensors at each order for use in macroscale problems. The newly extended multiscale theory is employed in the analysis of a structural boundary-value problem under in-plane loading, illustrating pronounced boundary effects. A combination approach proposed in the literature is subsequently employed to mitigate the boundary layer effects by explicitly accounting for the microstructural details in the boundary region. This combination approach produces accurate recovery of the local fields in both regions. The extension to in-plane problem marks FVBAHT as an alternative, self-contained asymptotic homogenization tool, with documented advantages relative to current numerical techniques, for the analysis of periodic materials in the presence of strain gradients produced by three-dimensional loading regardless of microstructural scale.
Rule Model for Selecting Dimensional Measurement Equipment in Inspection Planning
Authors: Feng Shaw C. , Horst John A. , Feeney Allison Barnard , Jones Albert T. , Kramer Thomas R. , Hedberg Thomas D. 
Published: August 2020

Abstract
Process uncertainty can have negative effects on part quality and is, therefore, critical to the safety and performance of products. Those effects are manifested in the dimensional measurement uncertainty associated with those parts and products. To minimize the effects of process uncertainties, the sources of dimensional uncertainty must be identified and clearly communicated to collaborators and suppliers. A principal source of dimensional uncertainty is the measurement equipment itself. This article presents an activity model, rule types, and sample rules for selecting dimensional metrology equipment. The activity model represents key operations and information flows associated with the dimensional measurement. Analysis of the included activity model facilitates the development of rule types for measurement equipment selection as described in the Quality Information Framework (QIF) standard. Rule types are based on design information and measurement requirements. Standard rule types enable industrial metrologists to capture, exchange, and share equipment selection rules with their collaborators. Example QIF rules are defined for successful and cost-saving use in planning a measurement process with functionally complex and appropriate dimensional measurement equipment.
On Debris-Fretting Impact—The Study of Oxide and Chromium Layer Application
Authors: Kopeć Marcin , Pašta Ondřej , Malá Martina , Halodová Patricie , Cvrček Ladislav , Krejčí Jakub 
Published: August 2020

Abstract
The fretting phenomenon was responsible for over 50% of fuel failure cases in the years 2010–2015 according to International Atomic Energy Agency (IAEA). It shows the scale of the problem for the nuclear power generation sector. A big share of this issue is related to debris fretting. Although debris fretting has been studied for decades, the available R&D information is scarce. The presented paper summarizes the work performed in the Research Center Řež (CVŘ) on Zr–1%Nb alloy tube specimens covered with protective coatings—passivation oxide layer and pure chromium layer. The tests included the simulation of debris-fretting conditions and detailed analysis using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and focused ion beam (FIB). Those experiments are a part of a wider project devoted to the research in the specification of the fretting wear increase after applying the protective layer. The first outputs show the positive impact even in the case of an oxide layer's presence on the cladding surface.
Nonuniform Kelvin Force Effect on Laminar Flow of Nanomaterials
Authors: Jafaryar M. , Sheikholeslami M. , Arabkoohsar A. , Shafee Ahmad 
Published: August 2020

Abstract
In the current study, Kelvin force as an external source has been used to affect the ferrofluid flow style. The presence of wire below the pipe creates a variable magnetic force that generates rotating eddies near the wire inside the pipe. To augment the cooling rate, the type of operating fluid changes from pure water to Fe3O4-water ferrofluid. Laminar flow was studied with involving homogeneous model for the ferrofluid. A new term was added to momentum equations as Kelvin force due to the gradient of the magnetic field. Impacts of magnetic number (Mn), the fraction of ferrofluid (φ), and Reynolds number (Re) on the configuration of hydrothermal behavior as well as Nusselt number (Nu) and Darcy factor (f) have been investigated. Utilizing ferrofluid can enhance Nu, while the pressure drop augmentation is negligible. So, selecting such kind of ferrofluid is a promising way to gain better performance. Given Re = 50, Nu enhances by about 1.3% with an increase of the concentration of ferrofluid from 0.01 to 0.04. The rise of Re needs greater pumping power as a higher pressure drop will appear in this case. Besides, a thinner boundary layer has been formed with the growth of Re, which offers a higher Nu. When Mn* = 1.57, the growth of Re provides an augmentation of Nu by 39%. With augmenting Kelvin force, the velocity of ferrofluid enhances, which results in a higher pressure drop.
Numerical Investigation of Fuel Property Effects on Mixed-Mode Combustion in a Spark-Ignition Engine
Authors: Xu Chao , Pal Pinaki , Ren Xiao , Sjöberg Magnus , Van Dam Noah , Wu Yunchao , Lu Tianfeng , McNenly Matthew , Som Sibendu 
Published: August 2020

Abstract
In this study, lean mixed-mode combustion is numerically investigated using computational fluid dynamics (CFD) in a spark-ignition engine. A new E30 fuel surrogate is developed using a neural network model with matched octane numbers. A skeletal mechanism is also developed by automated mechanism reduction and by incorporating a NOx submechanism. A hybrid approach that couples the G-equation model and the well-stirred reactor model is employed for turbulent combustion modeling. The developed CFD model is shown to well predict pressure and apparent heat release rate (AHRR) traces compared with experiment. Two types of combustion cycles (deflagration-only and mixed-mode cycles) are observed. The mixed-mode cycles feature early flame propagation and subsequent end-gas auto-ignition, leading to two distinctive AHRR peaks. The validated CFD model is then employed to investigate the effects of NOx chemistry. The NOx chemistry is found to promote auto-ignition through the residual gas, while the deflagration phase remains largely unaffected. Sensitivity analysis is finally performed to understand effects of fuel properties, including heat of vaporization (HoV) and laminar flame speed (SL). An increased HoV tends to suppress auto-ignition through charge cooling, while the impact of HoV on flame propagation is insignificant. In contrast, an increased SL is found to significantly promote both flame propagation and end-gas auto-ignition. The promoting effect of SL on auto-ignition is not a direct chemical effect; it is rather caused by an advancement of the combustion phasing, which increases compression heating of the end-gas.
Assessment of Conventional and Alternative Energy Carriers for Use in Military Vehicle Platforms
Authors: Mansfield A. , Boehman A. , Gorsich D. 
Published: August 2020

Abstract
Interest in alternative energy carriers for military transportation applications prompted significant investigation, which revealed military-specific benefits and challenges of electric hybrid energy carrier systems. In the years since these studies, the types and performance of alternative energy carrier technologies have rapidly advanced. The objectives of this work were to survey and characterize commercial and near-term transportation energy carriers and then assess their use in several specific military vehicles. Comprehensive databases were constructed which quantify the energy density, specific energy, and power density of various energy carriers, storage systems, and energy conversion devices, through a survey of the scientific and industrial literature. These databases were then used in conjunction with basic operating requirements for the high-mobility multipurpose wheeled vehicle and family of medium tactical vehicles military vehicle platforms to approximate the total powertrain mass as well as the total volume of stored energy, for various energy carriers for each vehicle platform. Results indicate that the use of pure gasoline or diesel fuels in these vehicle platforms yields by far the lowest total powertrain mass and stored energy; thus, despite recent advancements in alternative energy carrier technologies, significant powertrain mass and stored volume penalties for their implementation remain. Li ion battery diesel hybrids were the most promising near-term application of alternative energy carrier, with the commercialization of Li ion battery technologies found to have significantly reduced mass and volume penalties. The databases and trends developed here inform the broader consideration of alternative energy carriers used in military vehicles.
Investigation on the Radial Heat-Transfer of Pumping Secondary Flow in Semiclosed Rotating Disk Cavity
Authors: Luo Guohu , Yao Zhenqiang 
Published: August 2020

Abstract
This study investigates the mean flow and radial heat-transfer behaviors in semiclosed rotating disk cavity within the canned reactor coolant pump. The flow in the semiclosed cavity contains the Stewartson type flow at inner region and the Batchelor type flow at outer region. The heat is radially transported from the outer rim of the semiclosed disk cavity to discharge-hole through the nondirect discharge (ND) portion of the superimposed flow from inlet. The effects of rotating Reynolds numbers, cavity aspect ratio and radial location of discharge-hole on the discharge ratio, pumping mass flow rate, local wall shear stress and radial heat-transfer coefficient are examined in the semiclosed rotating cavity flow, respectively. Based on the radial heat transfer behaviors of pumping secondary flow, an equivalent thermal network is proposed and validated by experiments, which can effectively predict the radial temperature distribution from the discharge hole to periphery with the viscous-heating and nonisothermal effects.
The UGKS Simulation of Microchannel Gas Flow and Heat Transfer Confined Between Isothermal and Nonisothermal Parallel Plates
Authors: Dai Lianfu , Wu Huiying , Tang Jun 
Published: August 2020

Abstract
The unified gas kinetic scheme (UGKS) is introduced to simulate the near transition regime gas flow and heat transfer in microchannel confined between isothermal and nonisothermal parallel plates. The argon gas is used and its inlet Knudsen number (Knin) ranges from 0.0154 to 0.0715. It is found that: (1) both microchannel gas flows under isothermal and nonisothermal parallel plates display a trend of speed acceleration and temperature decrease along flow direction, for which the microscopic mechanism explanation is first proposed; (2) inlet gas streamlines under nonisothermal plates condition deviate from the parallel distributions under isothermal plates condition due to the dual driving effects of pressure drop along flow direction and temperature difference along cross section; (3) gas temperature, pressure, density and viscosity distributions along cross section under nonisothermal plates condition deviate from the parabolic distributions under isothermal plates condition, while the gas velocity keeps the parabolic distribution due to the effect of Knudsen layer; (4) as channel height increases or channel length and gas molecular mean free path decrease, the gas temperature distribution along cross section under nonisothermal plates condition tends to transition from linear to curve one due to the decreasing effect of heat transfer along cross section and increasing effect of gas acceleration along flow direction, this transition from linear to curve one becomes more obvious along flow direction. (5) the gas velocity under nonisothermal plates condition decreases with the increase of inlet gas temperature (Tin), lower plate temperature (Tl) and Knin, while the gas temperature increases with the increase of Tin, Tl and Knin.
Classification of a 3-RER Parallel Manipulator Based on the Type and Number of Operation Modes
Authors: Kong Xianwen 
Published: August 2020

Abstract
The type/number of operation modes of a parallel manipulator (PM) may vary with the link parameters of the PM. This paper presents a systematic classification of a 3-RER PM based on the type/number of operation modes. Here, R and E denote revolute joint and planar joint, respectively. The 3-RER PM was proposed as a 4-degree-of-freedom (DOF) 3T1R PM in the literature. Using the proposed method, classification of a PM based on the type/number of operation modes can be carried out in four steps, including formulation of constraint equations of the PM, preliminary classification of the PM using Gröbner cover, operation mode analysis of all the types of PMs using primary decomposition of ideals, and identification of redundant types of PMs. The classification of the 3-RER PM shows that it has 13 types. Besides the two 4-DOF 3T1R operation modes, different types of 3-RER PMs may have up to two more 3-DOF or other types of 4-DOF operation modes. Motion characteristics of the moving platform of 3-RER PMs are also identified using Euler parameter quaternions. This work is the first systematic study on the impact of link parameters on the operation modes of the 3-RER PM and provides a solid foundation for further research on the design and control of 3-RER PMs and other multi-mode (or reconfigurable) PMs.
An Assessment of Homogeneous Mixture Method Cavitation Models in Predicting Cavitation in Nozzle Flow
Authors: Villafranco Dorien O. , Gupta Ankush , Ryan Emily M. , Holt R. Glynn , Grace Sheryl M. 
Published: August 2020

Abstract
The homogeneous mixture method (HMM) is a popular class of models used in the computational prediction of cavitation. Several cavitation models have been developed for use with HMM to govern the development and destruction of vapor in a fluid system. Two models credited to Kunz and Schnerr–Sauer are studied in this paper. The goal of this work is to provide an assessment of the two cavitation submodels in their ability to predict cavitation in nozzle flow. Validation data were obtained via experiments which employ both passive cavitation detection, (PCD) via acoustic sensing and optical cavitation detection (OCD) via camera imaging. The experiments provide quantitative information on cavitation inception and qualitative information on the vapor in the nozzle. The results show that initial vapor formation is not predicted precisely but within reason. A sensitivity analysis of the models to input parameters shows that the Schnerr–Sauer method does not depend upon the estimation of nuclei size and number density. Small changes in the vapor formation rate but not the total vapor volume can be seen when weighting parameters are modified. In contrast, changes to the input parameters for the Kunz model greatly change the final total vapor volume prediction. The assessment also highlights the influence of vapor convection within the method. Finally, the analysis shows that if the fluid and nozzle walls do not support nuclei larger than 40 μm, the methods would still predict cavitation when indeed there would be none in practice.
A Water Droplet Impact on a Hydrophobic Soft Surface
Authors: Abubakar Abba Abdulhamid , Yilbas Bekir Sami , Al-Qahtani Hussain 
Published: August 2020

Abstract
Impacting water droplet on a hydrophobic soft surface is investigated and impacting droplet behavior during the spreading and retraction phases is examined. Polyisoprene elastomer surface is hydrophobized via deposition with functionalized nanosilica particles using the dip coating method. Hydrophobized surface results in the contact angle of 135 ± 3 deg with a hysteresis of 2 ± 1 deg, and stretching and stretch relaxing of the coated samples do not alter the wetting state of the surfaces. Pressure variation, spreading, and retraction rates of droplet are simulated and findings are validated through the experimental data obtained from high-speed video system. The findings are also compared to those obtained for the impacting droplet on the hydrophobized glass surfaces. It is observed that predictions of droplet height and droplet shape agree well with the experimental data. Spreading period of the impacting droplet on the hydrophobized elastomer surface is longer than the hydrophobic glass surface; contrary, the retraction period of the impacting droplet is shorter on the elastomer surface than the glass surface. Impacting droplet generates large amplitude oscillatory surface waves on the elastomer surface and as the time progresses the wave amplitude reduces considerably, particularly along the surface (x-axis).
Physical Activity Among Immigrant Children: A Systematic Review
Authors: Lacoste Yannick , Dancause Kelsey Needham , Gosselin-Gagne Justine , Gadais Tegwen 
Published: August 2020

Background: The health benefits of physical activity (PA) for children are well documented. However, little is known about PA patterns among immigrant children. Methods: The authors reviewed research on PA patterns of immigrant children. The inclusion criteria included peer-reviewed articles published from January 2010 to May 2018 in English, French, or Spanish that included primary-school-aged (6–12 y) children, and data on immigration status. Results: A total of 11 articles were included in the analyses. These studies revealed a deficit of PA among immigrant children. Immigration status (immigrant or nonimmigrant) and generation of immigration (first, second, and third), ethnic origin, and gender were associated with PA patterns. In general, PA levels were lower among first-generation immigrant children, children of Hispanic and East Asian origin, and girls. The results suggest that questionnaire measures might be biased or inaccurate among immigrant children, highlighting the need for the integration of mixed methods (objective and subjective measures). Conclusions: A large proportion of children do not meet PA guidelines, and this might be more problematic for immigrant children. Future studies incorporating time since immigration, comparative analyses on gender, sociocultural and socioeconomic characteristics, and mixed methodology could provide a more complete portrait of PA patterns and opportunities for immigrant children.
Young people’s views on their role in the COVID-19 pandemic and society’s recovery from it
Authors: Larcher Vic , Dittborn Mariana , Linthicum James , Sutton Amy , Brierley Joe , Payne Christopher , Hardy Hannah 
Published: August 2020

ObjectiveThere has been little formal exploration of how young people see their role in the COVID-19 pandemic.Design/settingFocus-group discussion with 15 Children’s Hospital Young People’s Forum members (23/5) to explore their perspective on the impact of COVID-19 on both their lives and those of their community, on school closures, and the role they wished to play in society’s recovery from the pandemic. Audio recordings were transcribed verbatim using NVivo Software and analysed using an inductive thematic analysis approach.OutcomeFour major themes identified: (1) Awareness of pandemic’s impact on others: participants showed mature awareness of the effects on broader society, especially the elderly, socially disadvantaged and parents. (2) Perceived impact on their own lives: principal concerns were the educational and practical repercussions of school closures and social isolation, including effects on educational prospects. (3) Views about school reopening: young people understood the broader rationale for school reopening and were generally positive about it, but expressed concerned about their safety and that of others. (4) Communication issues: a need for clear, concise, understandable information readily accessible for young people was expressed. Up to now, they felt passive recipients rather than participants.ConclusionYoung people were concerned about their future, their family and broader society, consistent with a high level of moral development. They want to be active participants in social recovery, including concepts around return to school but require appropriate information and a means by which their voices can be heard. The alternative suggested roles as pawns or pathfinders were discounted.
Practical metrics for establishing the health benefits of research to support research prioritisation
Authors: Woods Beth , Schmitt Laetitia , Rothery Claire , Phillips Andrew , Hallett Timothy B , Revill Paul , Claxton Karl 
Published: August 2020

IntroductionWe present practical metrics for estimating the expected health benefits of specific research proposals. These can be used by research funders, researchers and healthcare decision-makers within low-income and middle-income countries to support evidence-based research prioritisation.MethodsThe methods require three key assessments: (1) the current level of uncertainty around the endpoints the proposed study will measure; (2) how uncertainty impacts on the health benefits and costs of healthcare programmes and (3) the health opportunity costs imposed by programme costs. Research is valuable because it can improve health by informing the choice of which programmes should be implemented. We provide a Microsoft Excel tool to allow readers to generate estimates of the health benefits of research studies based on these three assessments. The tool can be populated using existing studies, existing cost-effectiveness models and expert opinion. Where such evidence is not available, the tool can quantify the value of research under different assumptions. Estimates of the health benefits of research can be considered alongside research costs, and the consequences of delaying implementation until research reports, to determine whether research is worthwhile. We illustrate the method using a case study of research on HIV self-testing programmes in Malawi. This analysis combines data from the literature with outputs from the HIV synthesis model.ResultsFor this case study, we found a costing study that could be completed and inform decision making within 1 year offered the highest health benefits (67 000 disability-adjusted life years (DALYs) averted). Research on outcomes improved population health to a lesser extent (12 000 DALYs averted) and only if carried out alongside programme implementation.ConclusionOur work provides a method for estimating the health benefits of research in a practical and timely fashion. This can be used to support accountable use of research funds.