bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of the public's use of PPE and strategies to avoid contagion during the COVID‐19 pandemic in Australia and Germany
Authors: Moore Kathleen A. , Bouchoucha Stéphane L. , Buchwald Petra 
Published: June 2021

AbstractThe SARS‐CoV‐2 or COVID‐19 pandemic has raised public awareness around disease protection. The aims in this study were to recruit participants from Australia and Germany to determine their use of personal protective equipment and COVID‐19 avoidance strategies using scales designed for this study. Principal components analysis with the Australian data revealed two factors in the Protection from Infection Scale, Self‐Care and Protective Behaviors, and a single factor in the Infection Avoidance Scale, with each scale demonstrating strong internal reliability. Data from German participants were used to confirm the scales' structure using confirmatory factor analysis. A comparison of the two data sets data revealed that Australian participants scored higher overall on protection and avoidance strategies but at the item level there were several commonalities, including self‐care behaviors people adopted to avoid contracting COVID‐19. With no foreseeable end to this pandemic, it is important that follow‐up studies ascertain whether the public continues to adopt high levels of PPE use and follows government advice or if pandemic fatigue sets in.
Automated calibration of smartphone cameras for 3D reconstruction of mechanical pipes
Authors: Maalek Reza , Lichti Derek D. 
Published: June 2021

AbstractThis paper outlines a new framework for the calibration of optical instruments, in particular smartphone cameras, using highly redundant circular black‐and‐white target fields. New methods were introduced for (i) matching targets between images; (ii) adjusting the systematic eccentricity error of target centres; and (iii) iteratively improving the calibration solution through a free‐network self‐calibrating bundle adjustment. The proposed method effectively matched circular targets in 270 smartphone images, taken within a calibration laboratory, with robustness to type II errors (false negatives). The proposed eccentricity adjustment, which requires only camera projective matrices from two views, behaved comparably to available closed‐form solutions, which require additional a priori object‐space target information. Finally, specifically for the case of mobile devices, the calibration parameters obtained using the framework were found to be superior compared to in situ calibration for estimating the 3D reconstructed radius of a mechanical pipe (approximately 45% improvement on average).
Nitrogen use plasticity in response to light intensity in neotropical tree species of distinct functional groups
Authors: Debiasi Tatiane Viegas , Calzavara Anderson Kikuchi , Sodek Ladaslav , Oliveira Halley Caixeta 
Published: June 2021

AbstractEnvironmental conditions influence the use of different nitrogen (N) sources by plants. We hypothesized that an increase in light intensity favors the use of nitrate (NO3−) relative to ammonium (NH4+) by seedlings of neotropical tree species from different functional groups, that is, Cecropia pachystachya (a shade‐intolerant species), Cariniana estrellensis (a shade‐tolerant canopy species), and Guarea kunthiana (a shade‐tolerant understory species). We analyzed the growth and N metabolism in seedlings simultaneously provided with NH4+ and NO3−, under lower (LL) and higher (HL) light intensity. 15N incorporation into amino acids was monitored after incubation with 15N‐labeled NH4+or NO3−. Under HL, all species showed decreased leaf area ratio, and increased growth, nitrate reductase activity and assimilated N content. Cecropia pachystachya increased the use of both N sources under HL, with substantial increases in 15N‐amino acids derived from 15NO3− (12.5‐ and 4.0‐fold in roots and leaves, respectively) and 15NH4+ (4.5‐ and 3.0‐fold in roots and leaves, respectively). Guarea kunthiana showed the greatest plasticity in N use, as the assimilation of 15NO3− in roots and leaves increased substantially under HL (11.2‐ and 17.0‐fold, respectively). Cariniana estrellensis increased the assimilation of 15NH4+ in roots and 15NO3− in leaves under HL. Therefore, the responses of N use strategies to light intensity varied with the species according to their ecological characteristics.
Bio‐mediated soil improvement: An introspection into processes, materials, characterization and applications
Authors: Jiang Ning‐Jun , Wang Yi‐Jie , Chu Jian , Kawasaki Satoru , Tang Chao‐Sheng , Cheng Liang , Du Yan‐Jun , Shashank Bettadapura S. , Singh Devendra N. , Han Xiao‐Le , Wang Yu‐Ze 
Published: June 2021

AbstractFor a long time in the practice of geotechnical engineering, soil has been viewed as an inert material, comprising only inorganic phases. However, microorganisms including bacteria, archaea and eukaryotes are ubiquitous in soil and have the capacity and capability to alter bio‐geochemical processes in the local soil environment. The cumulative changes could consequently modify the physical, mechanical, conductive and chemical properties of the bulk soil matrix. In recent years, the topic of bio‐mediated geotechnics has gained momentum in the scientific literature. It involves the manipulation of various bio‐geochemical soil processes to improve soil engineering performance. In particular, the process of microbial‐induced calcium carbonate precipitation (MICP) has received the most attention for its superior performance for soil improvement. The present work aims to shape a comprehensive understanding of recent developments in bio‐mediated geotechnics, with a focus on MICP. Referring to around one hundred studies published over the past five years, this review focuses on popular and alternative MICP processes, innovative raw materials and additives for MICP, emerging tools and testing methodologies for characterizing MICP at multi‐scale, and applications in emerging and/or unconventional geotechnical fields.
A New Method for Laplace Transforms of Multiterm Fractional Differential Equations of the Caputo Type
Authors: Fukunaga Masataka 
Published: June 2021

AbstractThe Laplace transform method is one of the powerful tools in studying the fractional differential equations (FDEs). In this paper, it is shown that the Heaviside expansion method for integer order differential equations is also applicable to the Laplace transforms of multiterm Caputo FDEs of zero initial conditions if the orders of Caputo derivatives are integer multiples of a common real number. The particular solution of a linear multiterm Caputo FDE is obtained by its Laplace transform and the Heaviside expansion method. A Caputo FDE of nonzero initial conditions is transformed to an Caputo FDE of zero initial conditions by an appropriate change of variables. In the latter, the terms originated from the initial conditions appear as nonhomogeneous terms. Thus, the solution to the Caputo FDE of nonzero initial conditions is obtained as the particular solutions to the equivalent Caputo FDE of zero initial conditions. The solutions of a linear multiterm Caputo FDEs of nonzero initial conditions are expressed through the two parameter Mittag–Leffler functions.
A Systematic Review of the Tensile Biomechanical Properties of the Neonatal Brachial Plexus
Authors: Orozco Virginia , Magee Rachel , Balasubramanian Sriram , Singh Anita 
Published: June 2021

AbstractBrachial plexus (BP) birth injury has a reported incidence of 1 to 4 per 1000 live births. During complicated deliveries, neonatal, maternal, and other birth-related factors can cause over-stretching or avulsion of the neonatal brachial plexus leading to injury. Understanding biomechanical responses of the neonate brachial plexus when subjected to stretch can offer insight into the injury outcomes while guiding the development of preventative maneuvers that can help reduce the occurrence of neonatal brachial plexus injuries. This review article aims to offer a comprehensive overview of existing literature reporting biomechanical responses of the brachial plexus, in both adults and neonates, when subjected to stretch. Despite the discrepancies in the reported biomechanical properties of the brachial plexus, available studies confirm the loading rate and loading direction dependency of the brachial plexus tissue. Future studies, possibly in vivo, that utilize clinically relevant neonatal large animal models can provide translational failure values of the biomechanical parameters for the neonatal brachial plexus when subjected to stretch.
Improve of Unsteady Pressure Pulsation Based on Jet–Wake Suppression for a Low Specific Centrifugal Pump
Authors: Wu Chengshuo , Li Qianqian , Zheng Feng , Wu Peng , Yang Shuai , Ye Haojie , Huang Bin , Wu Dazhuan 
Published: June 2021

Abstract
In this study, three impellers with different blade pressure side (PS) profiles are designed and the influence on the hydraulic and dynamic performance of a low specific speed centrifugal pump is investigated by numerical simulation and experimental research. The results show that blade PS modification introduced in this study can efficiently alleviate the unsteady pressure pulsation of model pump. In order to study the effects of blade modification on the internal flow filed, the volute domain is replaced by an even outlet region for computational fluid dynamic (CFD) analysis. Relative velocity distribution is extracted to visualize the three-dimensional (3D) flow characteristics at the impeller outlet. Results show that the flow at impeller outlet presents a typical jet–wake structure, which is significantly suppressed after the blade modification. The suppression of jet–wake structure, which is attributed to the redistribution of pressure and velocity in the impeller caused by the change of blade work capacity, can directly reduce the intensity of pressure pulsation in the volute by increasing the velocity uniformity at impeller outlet. Given that the existence of jet–wake flow results in large mixing loss and velocity deviation at the impeller outlet, entropy generation rate and slip velocity calculation are introduced here to measure the extent of jet–wake configuration. Results show that both indicators introduced here can be used to quantify the extent of the jet–wake structure at impeller outlet, and thus, indirectly predict the strength of unsteady pressure pulsation in pump volute.
Numerical Investigation on the Influences of Boundary Layer Ingestion on Tip Leakage Flow Structures and Losses in a Transonic Axial-Flow Fan
Authors: Yang Zhe , Lu Hanan , Pan Tianyu , Li Qiushi 
Published: June 2021

Abstract
In a boundary layer ingesting (BLI) propulsion system, the fan is continuously exposed to inflow distortions. The distorted inflows lead to nonuniform loss distributions along the radial and circumferential directions. Since the rotor tip suffers from higher intensive distortion, the local loss increment is a major contributor to the BLI fan performance penalty. To explore the effects of distorted inflows on tip leakage flow evolutions and associated mechanisms for increased loss in a BLI fan, three-dimensional full-annulus unsteady simulations are conducted. Results show that about 54% of total additional losses due to distortion are formed in the tip region and more than 80% of tip region entropy generation is related to the tip leakage flow. The intensities of leakage vortex–shock interactions vary at different annulus locations. When the rotor moves into the distorted region, the vortex–shock interaction is weaker than the undistorted locations due to attenuated leakage flow. At the locations where the rotor is moving out from the distorted region, the vortex–shock interaction is notably enhanced because the front part of the blade tip airfoil suffers a higher load, resulting in a rapid vortex core expansion and eventually vortex breakdown. The increase of flow blockage in the front section of blade tip passages at local circumferential positions leads to a corresponding rise of flow loss. The findings in this study highlight the impacts of tip leakage flow on aerodynamic loss of fan working under BLI inflow distortion and provide improved understandings of loss mechanisms in a BLI fan.
Effects of Blade Pressure Side Modification on Unsteady Pressure Pulsation and Flow Structures in a Centrifugal Pump
Authors: Wu Chengshuo , Zhang Wenqi , Wu Peng , Yi Jiale , Ye Haojie , Huang Bin , Wu Dazhuan 
Published: June 2021

Abstract
In this paper, the effects of modifying the blade pressure side (PS) on unsteady pressure pulsation and flow structures in a low specific speed centrifugal pump are carried out by experimental and computational fluid dynamics (CFD). Seven monitor points are arranged in the circumferential direction of the impeller outlet to capture the pressure signals in the volute at flow rate of 0.2–1.6Qd. Results show that the blade PS modification introduced here can significantly alleviate the amplitude of pressure pulsation at blade passing frequency (fBPF) in all concerned operation conditions. To study the effects of blade modification on the internal flow field, the volute domain is replaced by an even outlet region for CFD analysis. The shear stress transfer (SST) turbulence model is adopted for steady-state numerical simulation while the delayed detached eddy simulation (DDES) based on the SST approach is adopted for transient simulation. Results show that local unsteady velocity fluctuation is the dominant reason for pressure pulsation in the volute. After blade PS modification, the relative velocity distribution at the impeller outlet is more uniform and the intensity of shedding vortex at the blade trailing edge (TE) decreases significantly. The change of internal flow structure improves the uniformity of circumferential velocity distribution the downstream of the impeller outlet, which leads to the decrease of pressure fluctuation amplitude in the volute. Meanwhile, the local Euler head (LEH) distribution at the impeller outlet and the blade loading of PS are presented and compared. It can be concluded that the reduction of pressure pulsation attributes to a more uniform energy distribution at the impeller outlet which is achieved by actively unloading the PS of the modified blades.
Cutting to the Point: Directly Machined Metal Molds for Directional Gecko-Inspired Adhesives
Authors: Hajj-Ahmad Amar , Suresh Srinivasan A. , Cutkosky Mark 
Published: June 2021

Abstract
Fabrication techniques for gecko-inspired adhesives generally target mold durability, adhesive performance, and process efficiency and simplicity. With these goals in mind, we present a micromachining process for creating reusable aluminum molds used to fabricate directional dry adhesives. The molds require deep, narrow and overhanging grooves to create sharp and angled adhesive features. This geometry precludes most traditional machining and lithographic material removal processes. The presented process is a hybrid of indenting and orthogonal machining, using a diamond-coated microtome blade as the tool. An finite element analysis reveals the local extent of work hardening as each groove is created, and helps to define a trajectory that reduces the effects of tool deflection and chip build up. The results of a series of experiments agree with predictions from the analysis and reveal a range of blade approach angles and a lower bound on groove spacing to achieve the desired geometry. This range is narrower than for molds machined from wax in previous work. Nonetheless, adhesive samples cast from the new metal molds achieve comparable performance to those previously cast from wax.
Uncertainty Reduction for Model Error Detection in Multiphase Shock Tube Simulation
Authors: Park Chanyoung , Nili Samaun , Mathew Justin T. , Ouellet Frederick , Koneru Rahul , Kim Nam H. , Balachandar Sivaramakrishnan , Haftka Raphael T. 
Published: June 2021

Abstract
Uncertainty quantification (UQ) is an important step in the verification and validation of scientific computing. Validation can be inconclusive when uncertainties are larger than acceptable ranges for both simulation and experiment. Therefore, uncertainty reduction (UR) is important to achieve meaningful validation. A unique approach in this paper is to separate model error from uncertainty such that UR can reveal the model error. This paper aims to share lessons learned from UQ and UR of a horizontal shock tube simulation, whose goal is to validate the particle drag force model for the compressible multiphase flow. First, simulation UQ revealed the inconsistency in simulation predictions due to the numerical flux scheme, which was clearly shown using the parametric design of experiments. By improving the numerical flux scheme, the uncertainty due to inconsistency was removed, while increasing the overall prediction error. Second, the mismatch between the geometry of the experiments and the simplified 1D simulation model was identified as a lack of knowledge. After modifying simulation conditions and experiments, it turned out that the error due to the mismatch was small, which was unexpected based on expert opinions. Last, the uncertainty in the initial volume fraction of particles was reduced based on rigorous UQ. All these UR measures worked together to reveal the hidden modeling error in the simulation predictions, which can lead to a model improvement in the future. We summarized the lessons learned from this exercise in terms of empty success, useful failure, and deceptive success.
A Study of Influences of Inlet Total Pressure Distortions on Clearance Flow in an Axial Compressor
Authors: Zhu Guoming , Liu Xiaolan , Yang Bo , Song Moru 
Published: June 2021

Abstract
The rotating distortion generated by upstream wakes or low speed flow cells is a kind of phenomenon in the inlet of middle and rear stages of an axial compressor. Highly complex inflow can obviously affect the performance and the stability of these stages, and is needed to be considered during compressor design. In this paper, a series of unsteady computational fluid dynamics (CFD) simulations is conducted based on a model of a 1-1/2 stage axial compressor to investigate the effects of the distorted inflows near the casing on the compressor performance and the clearance flow. Detailed analysis of the flow field has been performed and interesting results are concluded. The distortions, such as total pressure distortion in circumferential and radial directions, can block the tip region so that the separation loss and the mixing loss in this area are increased, and the efficiency and the total pressure ratio are dropped correspondingly. Besides, the distortions can change the static pressure distribution near the leading edge of the rotor, and make the clearance flow spill out of the rotor edge more easily under near stall (NS) condition, especially in the cases with corotating distortions. This phenomenon can be used to explain why the stall margin is deteriorated with nonuniform inflows.
The Influence of Needle Eccentric Motion on Hole-to-Hole Injection Characteristics of a Two-Layered Eight-Hole Diesel Injector
Authors: Jin Tianyu , Sun Yu , Wang Chuqiao , Moro Adams , Wu Xiwen , Luo Fuqiang 
Published: June 2021

Abstract
The stringent emission regulations diesel engines are required to meet have resulted in the usage of multihole and ultramultihole injectors, nowadays. In this research study, a double-layered eight-hole diesel injection nozzle was investigated both numerically and experimentally. A three-dimensional model of the nozzle which was validated with experimental results was used to analyze the injection characteristics of each hole. The validation was conducted by comparing experiment and simulation injection rate results, acquired simultaneously from all the holes of the injector and the model. The fuel flow rates of the lower layered holes are higher than those of the upper layered holes. Two different needle eccentricity models were established. The first model only included the lateral displacement of the needle during needle lift. The needle reached maximum displacement at full needle lift. The second model considered the needle inelastic deformation into consideration. The needle radially displaces and glides along with the needle seat surface during needle lift. When the eccentricity reached a maximum in the radial direction, the needle began to lift upward vertically. The differences in injection characteristics under the different eccentricity models were apparent. The results indicated that the cycle injection quantity, fuel injection rate, and cavitation of each hole were affected during the initial lifting stages of the needle lift. As the eccentricity of the needle increases, the injection rate uniformity from the nozzle hole deteriorates. The result showed that the upper layered holes were affected by the needle eccentricity during needle lift.
Experimental Results of Local Shear Stresses and Friction Torque in an Open Rotor-Stator Disk System
Authors: Kuntze Alexander , Odenbach Stefan , Uffrecht Wieland 
Published: June 2021

Abstract
This contribution presents experimental investigations of friction torque in an open rotor–stator disk system by using two different measuring procedures. The first procedure is based on a thermo electrical wall shear stress sensor. The sensor is investigated in two different substrates and different measuring parameters. A thermal model consisting of the supplied heating power, the thermal resistance toward the fluid, and into the substrate as well as the over temperature is used to achieve the heat transfer coefficient on the sensor surface. This heat transfer coefficient is attributed by a functional relationship to the wall shear stress. This relationship is first calibrated in a rectangular channel and subsequently validated at a fully turbulent flat plat flow. The second measuring procedure based on the tangential displacement of the stator disk due the friction torque. The disk is attached at a torsion spring. The friction torque is achieved by the torsion spring constant and the tangential displacement of the stator disk. Both measuring procedures are compared and agree well with each other. The used test rig has the possibility of reaching rotational Reynolds numbers representative, for instance, of a modern gas turbine. The investigations were carried out by a 0.5 m diameter rotor disk rotating up to 8500 rpm with a gap ratio between 0.008 and 0.04. The friction torque is measured on the stator disk and can be converted into moment coefficient. Moment coefficient on stator and measured pressure distributions are presented for different gap ratios and rotational Reynolds number.