bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parental role‐modeling on 24‐hour movement behaviors among preschoolers during the COVID‐19 pandemic
Authors: Feng Jie , Khan Asaduzzaman , Lau Patrick Wing Chung , Huang Wendy Yajun 
Published: January 2024

AbstractIntroductionLittle is known about the association between parents' and children's 24‐h movement behaviors during the pandemic. This cross‐sectional study examined the association between the 24‐h movement behaviors of parents and their preschoolers and investigated sex differences in this association.MethodsA total of 1740 preschoolers (4.5 ± 0.8 years old, 50.3% boys) and their parents (35.4 ± 4.9 years old, 24.3% males) in China participated in this study and provided valid and complete data. Parents completed an online survey or a written questionnaire in the period between October and December 2020. Preschoolers' and parents' movement behaviors (physical activity [PA], sedentary behavior [SB], screen time, and sleep) and demographic information were reported by the parents. Generalized linear models and logistic regression models were performed.ResultsPositive associations were found between parents' and preschoolers' moderate‐to‐vigorous intensity PA (β = 0.28; 95% confidence interval [CI]: 0.20, 0.36), total PA (β = 0.21; 95% CI: 0.17, 0.24), and sleep (β = 0.05; 95% CI: 0.03, 0.06) with no apparent sex difference. No significant association was found between parents' and preschoolers' SB or screen time. Girls were more likely to meet all three 24‐h movement guidelines when their parents met them (odds ratio = 2.38; 95% CI: 1.42, 4.01), but the relationship was not significant for boys.ConclusionsParental role‐modeling was positively associated with children's PA and sleep. This finding suggests that supporting parents' movement behaviors has the potential to promote a healthy lifestyle among preschoolers.
Effects of Kinesio taping on lower limb biomechanical characteristics during unexpected jumping in patients with chronic ankle instability
Authors: Wang Ling , Chen Peng , Ding Yue , Fan Siyu , Wang Guanglan , Jia Shaohui , Guo Zhihao , Zheng Cheng 
Published: January 2024

AbstractPurposeThe current biomechanical research on the application of Kinesio taping (KT) to patients with chronic ankle instability (CAI) has focused on testing the expected movements. However, unexpected movements are more common in actual sports. Therefore, the present study aimed to investigate the effects of KT on the biomechanical characteristics of the knee and ankle joints during unexpected jumping movements.MethodsTwenty‐one patients with unilateral CAI were recruited to capture the biomechanical parameters during unexpected jumping movements under different interventions: no taping (NT), placebo taping (PT), and KT. A one‐way repeated measures analysis of variance was used to compare the differences in knee and ankle biomechanical characteristics among patients with CAI between the three intervention conditions.ResultsAt initial contact, the KT group demonstrated a significant decrease in ankle plantarflexion and knee flexion angles compared to the NT group (p < 0.05). At the early landing phase, the KT group had a significant increase in peak ankle dorsiflexion angle, peak ankle eversion angle, peak ankle dorsiflexion moment, and peak ankle eversion moment compared to the NT and PT groups (p < 0.05). Furthermore, the KT group had a significantly reduced peak knee flexion angle, peak knee eversion angle, and peak vertical ground reaction force (p < 0.05) compared to the NT and PT groups.ConclusionKT significantly improves the sprain‐prone touchdown posture of patients with CAI. And reducing the risk of ankle sprains during the early landing phase by promoting ankle dorsiflexion and eversion angles and moments.
A Novel Correlation for Considering the Effect of Neighboring Droplets on the Evaporation Rate of Solvent Droplets Used in Carbon Capture Applications
Authors: Parmar Gourav , Dhinasekaran Vignesh Kumar , Cejpek Ondrej , Jedelsky Jan , Avulapati Madan Mohan 
Published: January 2024

Abstract
The spraying of chemicals such as mono-ethanolamine (MEA) and aqueous ammonia is widely used in spray columns for CO2 removal from the combustion flue gasses. When droplets in the spray interact with flue gas, due to temperature difference, along with the absorption of CO2 from the flue gas, they also undergo evaporation. Also, the presence of other droplets in the vicinity of a given droplet can influence evaporation as well as gas absorption into it. Understanding the droplet evaporation and the influence of the surrounding droplets on the evaporation of droplets are one of the critical aspects to address for developing reliable models for CO2 capture from flue gasses. This work investigates the influence of neighboring droplets on evaporation of a droplet in question and comparison with evaporation of an isolated droplet. Various configurations of suspended droplets of water, aqueous ammonia, and MEA were examined within a temperature range spanning from 75 °C to 125 °C. The droplets, placed on a microfiber grid made up of 100 μm glass fiber, were introduced into a heating chamber, and temporal variation of the droplet size was recorded using backlit imaging. Images were processed using Matlab algorithms to obtain the droplet's evaporation rate. Variation in the evaporation rate is evaluated with respect to the temperature and available surface area for vapor diffusion. The results indicate that the presence of neighboring droplets influences the droplet evaporation, and the magnitude of influence depends both on the number of droplets as well as their proximity. Of the three liquids studied, influence of neighboring droplets found to be more significant in case of MEA. To consider the influence of neighboring droplets and their proximity, a novel independent parameter called surface area ratio (SAR) was introduced by combining both the parameters. The analysis involved investigating the variation in the normalized evaporation rate in relation to the SAR parameter. It was found that the normalized rate of evaporation under different conditions studied varies linearly with SAR. A correlation is developed between the normalized evaporation rate and SAR combining the data from all the cases studied which can be used to correct rate of evaporation in computational models.
Direct Numerical Simulation of Involute Channel Turbulence
Authors: Popov Emilian L. , Mecham Nicholas J. , Bolotnov Igor A. 
Published: January 2024

Abstract
A direct numerical simulation (DNS) study was performed on turbulent flow in the high flux isotope reactor involute channel geometry to develop a numerical database and determine the differences compared with a flat parallel channel. The varying channel curvature along the walls was studied for differences in mean profiles. Parameters of interest include streamwise velocity, turbulent kinetic energy (TKE), and turbulence dissipation rate, as well as Reynolds stresses and turbulence transport terms. Profile sampling was carried out at 10 locations along the span of the involute. Additional DNS studies were performed on smaller domains of comparable curvature to the involute domain: a high curvature channel (high circular), a low curvature channel (low circular), and a flat channel (flat). Each of these four cases was compared against each other and to other DNS studies performed on parallel flows. The results indicate that the bulk involute channel flow does not differ significantly from a flat parallel channel flow and that the curvature of the walls does not significantly alter the mean flow parameters. However, the regions of the involute channel near the side walls exhibit relatively low magnitude twin recirculation structures driven toward the side walls from the centerline of the channel, which warrants further study.
Simulation and Experimental on Thermal Behavior of Hydrostatic Thrust Bearing Based on Superhydrophobic/Oleophobic Surface
Authors: Guo Minghui , Zhang Guojun , Hu Haidong , Tian Zhuxin , Rong Youmin , Huang Yu , Wu Congyi 
Published: January 2024

Abstract
The temperature rises of the oil film in hydrostatic bearings at high speed lead to a reduction in load capacity, accuracy, and stability. In this paper, a superhydrophobic/oleophobic surface with a micro-bulge structure is proposed. The surface is prepared by laser cross-scanning and chemical modification. The contact angle (CA) of the surface is 138 deg and the boundary condition of the surface is modified from non-slip to slip condition. The relationship between the slip length and the height of the micro-bulge structure is established by rheological experiments. By the simple partial simulations, the validity of the temperature rise reduction on the superhydrophobic/oleophobic surface is verified. Then a bearing test rig was set up to measure the temperature and load capacity of bearings at multiple points, and the performance of smooth primary surface/structured oleophobic surface thrust bearings was compared. Results show that the structured bearing has a lower oil film temperature and higher load capacity than the smooth bearing. The prepared oleophobic surface can effectively suppress the temperature rise at high-speed conditions and significantly increase the bearing load capacity.
Optimization of Controlling Factors for TC4 Alloy With Al2O3–Graphene Hybrid Nanofluid
Authors: Israr Asif , Khan Muhammad Zubair , Ikram Ruqia , Qureshi Yumna , Wattoo Kashif Riaz 
Published: January 2024

Abstract
Nowadays, mixing nanoparticles into cutting fluids is much more common to improve lubrication and cooling properties. Many studies have been carried out in the past to assess the machining performance using nanofluids. However, limited studies are based on hybrid nanoparticles. This work estimates TC4 alloy machining performance using a hybrid nanofluid. The minimum quantity lubrication (MQL) cooling technique is employed here to investigate machinability. The machining performance of TC4 alloy is estimated by taking surface roughness and cutting temperature as response parameters. Hybrid nanofluid is formed by adding nanoparticles of graphene into alumina (Al2O3) based nanofluid in a fixed volumetric proportion (20:80) and as base fluid, soybean oil is used. In addition, machining performance is investigated in terms of thermophysical properties by taking weight percent of concentrations of nanoparticles as 0.25, 0.50, 0.75, and 1.00, respectively. Significant improvements are observed in thermophysical properties with the hybridization of Al2O3 and graphene (Al2O3–GnP). Experimentation and parametric optimization are carried out using Taguchi's method. Controlling factors of hybrid nanofluid of alumina–graphene and monotype nanofluid of alumina are compared. The obtained results show that these parameters significantly reduce using hybrid nanofluid.
Predicting Diesel Engine Cetane Number and Similarity for Newer Commercial Sustainable Aviation Fuels
Authors: Cowart Jim , Dickerson Terrence , Luning Prak Dianne 
Published: January 2024

Abstract
A database of physical and chemical properties from one-hundred different jet fuels was used to create supervised Machine Learning (ML) models that predict Derived Cetane Number (DCN) as well as an unsupervised Self Organizing Map (SOM) of these conventional fuels. The best supervised ML models predict jet fuel DCN with just over one CN average error. The two dominant physical properties in the determination of DCN are fuel density and T50. The various models agree with increases in n-alkanes leading to higher DCN values, while increases in cyclo-aromatic content leading to decreases in DCN.
The prediction of eleven newer Sustainable Aviation Fuel (SAF) DCNs showed at best errors of 3 to 5 DCN which corresponds to a 5 to 10 percent prediction error. There were two SAF anomalies with much greater DCN prediction errors (over-prediction), as these two fuels are heavily branched iso-alkanes with very low DCNs.
An unsupervised ML approach was also used to characterize fuel similarity. The unsupervised SOM created and trained with the conventional jet fuels was then used to evaluate the SAF fuels. Two of the SAFs which had DCNs similar to the baseline database fuel mean had Quantization Errors (QEs) double the average QE of the database fuels. The two low DCN iso-alkane branched SAF fuels had very high QEs and thus were correctly determined by the SOM ML based approach as most dissimilar to the conventional jet fuels. This unsupervised ML approach shows promise for detecting new fuel differences early in the fuel evaluation process.
The Use of PD Patterns to Evaluate the Wear-Resistance and Manufacturing Quality to Estimate Expected Lifetime of Ignition Coils
Authors: Tidholm Johan , Gordon Martin , Hammarström Thomas 
Published: January 2024

Abstract
Partial discharges (PDs) are localized flashovers that occur within electrical insulation, when the electric field exceeds its dielectric strength. The electrical insulation, which covers the distance between conductive parts is also referred to as the dielectricum. In ignition coils, typically two different insulation materials are used: epoxy and transformer oil. Epoxy has the advantage of making the construction independent of positioning but its dielectric strength is sensitive to the potting process. Using oil as electrical insulation is less process sensitive than epoxy but the construction becomes more challenging as it must encapsulate its insulation material. An additional disadvantage is that an oil-insulated ignition coil can generally only be operated in certain positions, but it gains the advantage of being self-healing after dielectric breakdowns within the oil. Epoxy-insulated ignition coils lack this property as electrical trees are created within the insulation. These trees are gas-filled cavities that grow in size with the number of occurred PDs. In high performance ignition coil design, the maximum field strength should not exceed the dielectric strength of the insulation material. However, impurities locally decrease the dielectric strength and increase the electric field level. Thus, PDs are initiated at these impurities or defects and with time, the electric trees will continue to grow until the ignition coil breaks due to insulation breakdown. In epoxy-insulated ignition coils, a defect can be introduced as a crack due to internal forces caused by differences in thermal expansion co-efficients of the insulation system materials, even at normal operational temperatures. Therefore, measuring how homogeneous, free from impurities like gas bubbles, cracks and charred compounds, the epoxy is after the potting process could be a vital tool for monitoring manufacturing quality. An important aspect for an ignition coils performance is how temperature-wear-resistant, the resistance to cracking induced by a set of temperature cycles, it is. By measuring PDs, there is a possibility to quantify these quantities at a great resolution.
Generally, an increase in the number of temperature cycles is observed to cause an enlarged PD activity within the insulation system, which is believed to be related to possible detrimental temperature differences within a single temperature cycle. This, in turn, is related to a reduction in insulation lifetime. The goals of this study are to fit the measured data to an inverse power law model for estimating lifetime and investigate whether we can detect which failure mode caused an ignition coil to break.
High-Performance Alloys for Conventional ICE and Hydrogen ICE Applications
Authors: Frehn Andreas , Krus David , Mack Steffen 
Published: January 2024

Abstract
Currently, there are various development trends in conventional internal combustion engines (ICE) towards alternative concepts to save CO2 and improve the green footprint. One of these new solutions is the hydrogen internal combustion engine (HICE), which uses a concept with a similar engine design to burn hydrogen with oxygen to produce H20 and thus generate energy. Such engines are currently being tested on various test rigs to determine their long-term behavior, generally using materials that have already been used for conventional ICEs. This raises the question of whether these materials can withstand the changed conditions inside and outside the combustion chamber. This is because the element hydrogen, due to its small size, can penetrate almost any material and significantly reduce the ductility. This behavior is denoted by hydrogen embrittlement and can cause dramatic fracture during material and/or component production as well as in the subsequent operation phase. The purpose of this paper is to present various high-performance alloys that have yielded technical advantages in conventional ICEs in previous research and are already used in various components in those vehicles. Based on these existing material concepts, investigations were carried out to test these materials for their suitability in hydrogen-rich atmospheres in order to have alternatives for the existing materials used in HICEs.
Quantitative Validation of a Computational Fluid Dynamics Methodology for Gasoline Sprays Under Cold Start Conditions
Authors: Assanis Dimitris , Hwang Joonsik , Guleria Gaurav , Lopez-Pintor Dario , Wagnon Scott W. , Whitesides Russel 
Published: January 2024

Abstract
Computational Fluid Dynamics (CFD) simulations have a great potential to guide the optimization of fuel stratification strategies for internal combustion engines, but well-validated spray models are required. In this study, we aim to understand the current capability of CFD simulations, under conditions representative of partially stratified advanced compression ignition engines, to predict gasoline sprays through quantitative comparisons based on liquid measurements. A series of backlit extinction imaging is carried out in a constant volume vessel under simulated engine-like cold start conditions. As a test fuel, regular E10 gasoline is injected using a commercial gasoline direct-injection (GDI) injector at two different injection pressures of 50 bar and 100 bar. High-speed imaging datasets were used to obtain quantitative measurements of the liquid penetration, and local liquid volume fraction from line-of-sight integration and computed tomographic reconstruction. Additionally, geometric information by x-ray computed tomography is provided to set initial and boundary conditions for the CFD simulations. Multidimensional large-eddy simulations (LES) of the gasoline fuel spray in a constant volume chamber are presented and compared to the experimentally obtained fundamental validation data. A well-validated surrogate fuel for regular E10 gasoline, called PACE-20, was used in the simulations. Detailed comparison between experiments and simulations shows faster spray development and evaporation of LES studies, leading to slightly longer liquid penetration lengths. Further, the numerical simulations were able to capture the strong plume collapsing of the tested injector under these conditions and to properly reproduce the experimental trends and the effects of injection pressure on the liquid spray.
Computational Investigation on the Effects of Pre-Chamber Volume in an Active Narrow-Throat Pre-Chamber Engine
Authors: Silva Mickael , Liu Xinlei , Hlaing Ponnya , Cenker Emre , Al-Ramadan Abdullah , Turner James W. G. , Im Hong G. 
Published: January 2024

Abstract
To understand key physical aspects of volume in narrow-throat pre-chambers, computational fluid dynamics simulations were performed using CONVERGE™. A major advantage of a narrow-throat feature is to allow for drop-in replacement of a diesel injector, hence facilitating technology deployment. Despite broad literature on conventional pre-chambers, the narrow-throat has been shown to induce a different behavior, hence a thorough computational characterization is needed. The considered simulations were at lean conditions with methane, except the pre-chamber, which was additionally fueled thus providing an active mode of operation. The modeling work was validated with experiments and provided additional insights into key remaining questions on the small and large pre-chambers effects. The G-Equation combustion model was adopted; Peters’ turbulent flame speed correlation was used, while a skeletal methane mechanism was used for tabulating the laminar flame speed. The simulation data reveals that reducing the volume leads to significant stratification and low turbulence inside the pre-chamber. This combined with lower surface area led to lower heat transfer losses when compared to larger pre-chambers. Furthermore, the shorter jet issuing duration of small pre-chambers caters to longer combustion duration, as the turbulence and convection from the jets quickly dissipate. The Borghi-Peters diagram was further utilized to correlate the results with fundamental quantities and expected turbulent regimes encountered for the different pre-chambers.
Ignition Systems for SI-ICE Fueled by Alternative and Renewable Fuels
Authors: Ängeby Jakob , Tidholm Johan , Gustafsson Bert , Johnsson Anders 
Published: January 2024

Abstract
The requirements and challenges when designing a spark ignition system for hydrogen SI-ICE applications is presented. The ignition system needs to provide higher than usual voltages to provide robust ignition and sparks with low energy to minimize the sparkplug electrode wear, which are contradictory requirements when using a basic inductive ignition system. A general overview of spark ignition system design is presented. The features and capabilities of a system using a capacitive spark energy storage and an ignition control module that enables control of the available spark voltage, the duration and the current is presented. Results from extensive measurements heavy duty SI-ICE show that robust ignition is achieved at medium and high load using the shortest possible spark duration (∼40 μs) and a total spark energy of 2–5 mJ. A basic inductive ignition system typically delivers spark durations of 1500 μs and an energy of ∼90 mJ under the same condition. Control of spark characteristics can reduce the electrode wear significantly and reduce the electrode temperature, reducing the risk for preignition. The results apply also to other renewable and alternative fuels, such as biogas and hythane.