bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring the role of healthy dogs as hosts of enterohepatic Helicobacter species using cultivation‐dependent and ‐independent approaches
Authors: Ochoa Sofía , Ojeda Javier , Martínez Oscar A. , Vidal‐Veuthey Boris , Collado Luis 
Published: February 2021

AbstractEnterohepatic Helicobacter (EHH) species have been increasingly associated with acute gastroenteritis, inflammatory bowel disease and hepatobiliary diseases in humans. However, their host range and transmission routes are poorly understood. Therefore, the aim of this study was to determine the presence of EHH in healthy dogs using both cultivation‐dependent and ‐independent methods. Three hundred and ninety faecal samples from domestic dogs without gastrointestinal symptoms were analysed between June 2018 and July 2019 in Valdivia (South of Chile). Samples were inoculated on selective medium and in parallel were filtrated over an antibiotic‐free blood agar. Both media were incubated in a microaerobic atmosphere at 37°C for 7 days. Colonies were identified by PCR and phylogenetic analysis. A subset of 50 samples (half of them positive for EHH by cultivation and the remaining half negative) was analysed by PCR‐Denaturing Gradient Gel Electrophoresis (PCR‐DGGE) for direct detection. Cultivation method detected EHH in 15.4% (60/390) of the samples, being the most prevalent species H. canis (5.8%, 23/390) and H. canicola (5.1%, 20/390), followed by H. bilis (3.6%, 14/390) and ‘H. winghamensis’ (1.3%, 5/390). In contrast, PCR‐DGGE method detected Helicobacter DNA in almost all (96%, 48/50) tested samples. On the other hand, the method used also allowed to isolate other Campylobacterales, in fact 44.3% (173/390) of the samples were positive for Campylobacter upsaliensis (43.3%, 169/390) followed by C. jejuni (2.0%, 8/390). Moreover, two strains that presented Campylobacter‐like morphology were finally identified as Anaerobiospirillum succiniciproducens. Our results indicate that healthy domestic dogs commonly carry EHH and other Campylobacter species. However, further studies are needed to determine whether and how these Helicobacter and Campylobacter species can be transmitted to humans.
A Selection Strategy for Kriging Based Design of Experiments by Spectral Clustering and Learning Function
Authors: Li Rui , Liang Xihui , Peng Qingjin 
Published: February 2021

Abstract
Reliability analysis evaluates the failure probability of structures considering random variables of a system. Existing methods such as first-order reliability method (FORM) and second-order reliability method (SORM) are difficult to predict the failure probability of implicit functions in mechanical structures. Monte Carlo simulation (MCS) can predict the failure probability with high accuracy, but it is time-consuming. Agent-based methods such as the Kriging model have the approved performance to predict the failure probability in both efficiency and accuracy. An active method is proposed in this paper to improve the efficiency of predicting the probability of failures by combining the Kriging model and MCS, using a new learning function and its stopping condition. A representative selection strategy is developed based on spectral clustering to decide sample points in the design of experiments (DoEs). The new learning function integrates uncertainty and similarity of predicted Kriging values to search the next best sample point for updating the initial DoE. The learning process is terminated based on the stopping condition for a given accuracy of predicted probability of failures. Four case studies are conducted to validate the proposed method. Results show that the proposed method can predict the probability of failures with improved accuracy and reduced time.
Effects of Size and Surface Treatment on Fatigue Life of Fused Filament Fabrication Manufactured Acrylonitrile Butadiene Styrene Parts
Authors: Huang Jianchi , Miscles Eduardo , Mellor Tara , Ma Chao , Kuttolamadom Mathew , Wang Jyhwen 
Published: February 2021

Abstract
An experimental study was conducted to study the effects of geometric size and surface treatment on the fatigue life of fused filament fabrication (FFF) manufactured acrylonitrile butadiene styrene (ABS) parts. Moore rotating-beam fatigue tests were conducted with four different levels of loadings to obtain the S–N curves. Two different sizes (control size and large size) and three different surface treatment methods (as-printed, acetone-treated, and sandpaper polished) were studied. The larger specimens had significantly decreased fatigue life because of a larger volume, and hence a greater probability of defects for crack initiation and propagation, as compared with the control specimen. The acetone-treated specimen had a smooth surface. Its fatigue life, however, decreased significantly because the acetone treatment caused internal damage that weakened the specimen and was reported for the first time. The sandpaper polished specimen also had a smooth surface, but its effect on the fatigue life was insignificant because the extruded filament direction on the specimen surface was parallel to the loading direction. The present results lead to a better understanding of the effects of geometric size and surface treatment on the fatigue performance of FFF specimens. The study also provides important insights for the design of part size and surface treatment of three-dimensional (3D) printed plastic components for fatigue loading end-use applications.
An Experimental and Numerical Study on Coaxial Extrusion of a Non-Newtonian Hydrogel Material
Authors: Yu Ilhan , Chen Roland 
Published: February 2021

Abstract
Coaxial extrusion is a commonly used process to manufacture tubular structures to mimic vascular systems in 3D bioprinting. In this study, the stability of coaxial extrusion of a non-Newtonian material, Pluronic F127, is investigated. The extrusion process is considered stable when the extrudate form a core-annular structure. When it is unstable, dripping or jetting of the inner fluid is observed. In this study, the effects of the viscosity ratio, flowrate ratio, and the non-Newtonian behaviors on the stability of the coaxial extrusion process are investigated experimentally and numerically. The results show that all three factors can affect the stability of the process. When the ratio of viscosities increases, the process becomes unstable. The extrusion process tends to be stable when the flowrate of the outer fluid is much higher than that of the inner fluid. When the overall flowrate decreases, due to the non-Newtonian fluid behavior, the extrusion process can become unstable. This study shows the interconnected relationship between viscosity, flowrate, and non-Newtonian fluid behaviors and their effects on the stability of the coaxial extrusion process. The non-Newtonian flow behavior needs to be considered when studying or using coaxial extrusion. This study also provides a guiding principle on how to alter extrusion parameters in order to achieve the desired flow pattern.
Analysis of the Effect of Tool Posture on Stability Considering the Nonlinear Dynamic Cutting Force Coefficient
Authors: Li Zepeng , Yan Rong , Tang Xiaowei , Peng Fangyu , Xin Shihao , Wu Jiawei 
Published: February 2021

Abstract
In aviation and navigation, complicated parts are milled with high-speed low-feed-per-tooth milling to decrease tool vibration for high quality. Because the nonlinearity of the cutting force coefficient (CFC) is more evident with the relatively smaller instantaneous uncut chip thickness, the stable critical cutting depth and its distribution against different tool postures are affected. Considering the nonlinearity, a nonlinear dynamic CFC model that reveals the effect of the dynamic instantaneous uncut chip thickness on the dynamic cutting force is derived based on the Taylor expansion. A five-axis bull-nose end milling dynamics model is established with the nonlinear dynamic CFC model. The stable critical cutting depth distribution with respect to tool posture is analyzed. The stability results predicted with the dynamic CFC model are compared with those from the static CFC model and the constant CFC model. The effects of tool posture and feed per tooth on stable critical cutting depth were also analyzed, and the proposed model was validated by cutting experiments. The maximal stable critical cutting depths that can be achieved under different tool postures by feed per tooth adjustment were calculated, and corresponding distribution diagrams are proposed for milling parameter optimization.
Design for Manufacturing: Geometric Manufacturability Evaluation for Five-Axis Milling
Authors: Chen Niechen , Frank Matthew C. 
Published: February 2021

Abstract
The geometric manufacturability of a part design is an important decision factor for various manufacturing applications and is especially critical for the machining process. In machining, the geometric manufacturability is primarily determined by geometric accessibility, which has a direct impact on decisions such as setup planning, tool selection, tool orientation selection/adjustment, and the tool path strategies. These planning decisions can have a significant impact on cycle time and cost. Thus, it can be justified that geometric manufacturability is one of the essential product design aspects that must be evaluated for machining processes. Being able to evaluate the geometric manufacturability will not only provide a part design metric but also offer a new approach for manufacturing process planning and optimization. This research proposes a new method for determining the geometric manufacturability of a part designed for five-axis milling. In this work, the part design is input as polygon mesh boundary represented models, the 3D tool geometry is sampled to line segments, the 3D geometric accessibility of the part design is calculated, and a new metric for five-axis milling manufacturability evaluation is developed. Case studies on complex mechanical component design examples are conducted to validate the method.
Analysis of a New Process of Forging a 2017A Aluminum Alloy Connecting Rod
Authors: Winiarski Grzegorz , Dziubińska Anna 
Published: February 2021

Abstract
The paper presents the results of a theoretical analysis of a new process of hammer forging of a connecting rod and the technology currently used. In the industry at present connecting rods are forged from extruded rods. The new forging technology assumes the use of a workpiece in the form of a cast preform. For the calculations, it has been assumed that the billet material will be a Ø30 × 148 mm rod and a cast preform. Two variants of preforms have been modeled, from which products of the assumed geometry with different degree of strain are obtained. Calculations were made using the finite element method (FEM) in the Deform 3D program. The input material was 2017A aluminum alloy in the form of rods and sand cast preforms. On the basis of the conducted research, it was found that the use of cast preforms reduces material waste by about 80% in relation to the technology of forging from the bar and reduces the energy consumption of the process by about 75%. Both geometrical variants of the forging preforms ensure obtaining a forging with the assumed shape and dimensions, although forging from the forging preform with a smaller degree of strain seems to be a safer variant in terms of the possibility of cracking of the material. This is supported by the lower strain and normalized Cockcroft–Latham integral values.
Function Block-Based Multimodal Control for Symbiotic Human–Robot Collaborative Assembly
Authors: Liu Sichao , Wang Lihui , Wang Xi Vincent 
Published: February 2021

AbstractIn human–robot collaborative assembly, robots are often required to dynamically change their preplanned tasks to collaborate with human operators in close proximity. One essential requirement of such an environment is enhanced flexibility and adaptability, as well as reduced effort on the conventional (re)programming of robots, especially for complex assembly tasks. However, the robots used today are controlled by rigid native codes that cannot support efficient human–robot collaboration. To solve such challenges, this article presents a novel function block-enabled multimodal control approach for symbiotic human–robot collaborative assembly. Within the context, event-driven function blocks as reusable functional modules embedded with smart algorithms are used for the encapsulation of assembly feature-based tasks/processes and control commands that are transferred to the controller of robots for execution. Then, multimodal control commands in the form of sensorless haptics, gestures, and voices serve as the inputs of the function blocks to trigger task execution and human-centered robot control within a safe human–robot collaborative environment. Finally, the performed processes of the method are experimentally validated by a case study in an assembly work cell on assisting the operator during the collaborative assembly. This unique combination facilitates programming-free robot control and the implementation of the multimodal symbiotic human–robot collaborative assembly with the enhanced adaptability and flexibility.
Additive Manufacturing of 316L Stainless Steel by a Printing-Debinding-Sintering Method: Effects of Microstructure on Fatigue Property
Authors: Jiang Dayue , Ning Fuda 
Published: February 2021

Abstract
Additive manufacturing (AM) technology has been broadly applied to the fabrication of metallic materials. However, current approaches consume either high energy or large investment that considerably elevates their entry threshold. An economic extrusion-based AM method followed by debinding and sintering could efficiently produce the metal parts with relatively low cost and high material utilization. However, an in-depth analysis of the fatigue performance of the component built by such a technology has been little documented so far. Herein, the 316L stainless steel was fabricated throughout the printing-debinding-sintering (PDS) pathway and its fatigue properties were comprehensively assessed. Tensile and flexural fatigue tests were conducted to reveal the fatigue strength and fractural behaviors under different loading conditions, while the fatigue crack growth (FCG) test was performed to quantify the crack propagation. The results indicated the number of 105 cycles can be reached for the tensile specimens under the fatigue loading of 120 MPa, whereas 1.37 × 105 cycles were endured by the flexural specimens under 150 MPa. The fractural morphology indicated an adverse impact of the pore-induced voids on the tensile fatigue crack propagation, but such a drawback could be alleviated in the flexural loading condition. The FCG test unveiled the crack growth rate with the number of cycles and determined the material-related coefficients in the fatigue crack growth model. The research findings provided valuable insights into the effects of the PDS process and microstructures on the resultant fatigue properties of the metal component.
Application of Floquet Theory to Human Gait Kinematics and Dynamics
Authors: Bhat Sandesh G. , Subramanian Susheelkumar C. , Sugar Thomas S. , Redkar Sangram 
Published: February 2021

AbstractIn this work, the lower extremity physiological parameters are recorded during normal walking gait, and the dynamical systems theory is applied to determine a stability analysis. The human walking gait pattern of kinematic and dynamical data is approximated to periodic behavior. The embedding dimension analysis of the kinematic variable's time trace and use of Taken's theorem allows us to compute a reduced-order time series that retains the essential dynamics. In conjunction with Floquet theory, this approach can help determine the system's stability characteristics. The Lyapunov–Floquet (L-F) transformation application results in constructing an invariant manifold resembling the form of a simple oscillator system. It is also demonstrated that the simple oscillator system, when re-mapped back to the original domain, reproduces the original system's time evolution (hip angle or knee angle, for example). A reinitialization procedure is suggested that improves the accuracy between the processed data and actual data. The theoretical framework proposed in this work is validated with the experiments using a motion capture system.
Effects of Vertical Motions on Roll of Planing Hulls
Authors: Tavakoli Sasan , Dashtimanesh Abbas , Mancini Simone , Mehr Javad A. , Milanesi Stefano 
Published: February 2021

AbstractRoll motion of a planing hull can be easily triggered at high speeds, causing a significant change in hydrodynamic pressure pattern, which can threaten the stability of the vessel. Modeling and investigating roll motion of a planing vessel may require a strong coupling between motions in vertical and transverse planes. In the present paper, we have used a mathematical model to analyze the roll of a planing hull by coupling surge, heave, pitch, and roll motions using 2D + T theory to study the effects of roll-induced vertical motions on roll coefficients and response. Mathematically computed forces and moments as well as roll dynamic response of the vessel are seen to be in fair quantitative agreement with experimentally measured values of previously published data. Using the 2D + T method, it has been shown that to model the roll of a planing hull at high speeds, we need to consider the effects of heave, pitch, and surge motions. Through our mathematical modeling, it is found that freedom in vertical motions increases time-dependent roll damping and added mass coefficients, especially at early planing speeds. The results of dynamic response simulations suggest that freedom in the vertical plane can decrease the roll response.
Salvesen’s Method for Added Resistance Revisited
Authors: Amini-Afshar Mostafa 
Published: February 2021

Abstract
Almost 4 years after the appearance of Salvesen–Tuck–Faltinsen (STF) strip theory (Salvesen et al., 1970, “Ship Motions and Sea Loads,” Annual Meeting of the Society of Naval Architecture and Marine Engineers (SNAME), New York, Nov. 12–13), Salvesen in 1974 published his popular method for calculation of added resistance (Salvesen, 1974, “Second-Order Steady State Forces and Moments on Surface Ships in Oblique Regular Waves,” Vol. 22; Salvesen, 1978, “Added Resistance of Ships in Waves,” J. Hydronautics, 12(1), pp. 24–34). His method is based on an exact near-field formulation; however, he applied the long-wave and the weak-scatterer assumptions to present his approximate method using the integrated quantities (hydrodynamic and geometrical coefficients). Considering the available computational powers in the 1970s, both of these assumptions were absolutely justifiable. The intention of this paper is to disseminate the results of a recent study at the Technical University of Denmark, whereby the Salvesen’s formulation has been revisited and the added resistance is computed from the original exact equation without invoking the weak-scatterer or the long-wave assumptions. This is performed using the solutions of the radiation and the scattering problems, obtained by a low-order boundary element method and the two-dimensional free-surface Green function inside our in-house STF theory implementation (Bingham and Amini-Afshar, 2020, DTU_Strip Theory Solver). The weak-scatterer assumption is then removed through a direct calculation of the x-derivatives of the velocity potentials and the normal vectors along the body. Knowing the velocity potentials over each panel, the long-wave assumption is also avoided by a piece-wise analytical integration of sectional Kochin Function (Kochin, 1936, “On the Wave Resistance and Lift of Bodies Submerged in Fluid,” Transactions of the Conference on the Theory of Wave Resistance, Moscow.). The presented results for five ship geometries testify that the correct treatment of the original equation is achieved only after both of the above-mentioned assumptions are removed. Implemented in this manner, Salvesen’s method proves to be relatively more accurate and robust than has been generally perceived during all these years.
Evaluation of Optical Transmissivity of Transparent Materials on the Performance of Solar Flat Plate Collectors
Authors: Shaik Saboor , Bhardwaj Manvendra , Agarwal Somya , Yendaluru Raja Sekhar , Hasanuzzaman Md. , Sharma K. V. 
Published: February 2021

Abstract
The energy gain of domestic solar water heating systems is determined by solar to thermal energy conversion and glazing optical efficiency. For this study, solar transmission properties of different transparent glazing materials such as acrylic, low-iron, medium-iron, and high-iron glasses were measured. The collector thermal efficiency under natural convection mode was compared for different transparent covers determined by numerical simulation using the Hottel–Whillier–Bliss equation. The low-iron glass (LiG-12 mm) has 16.3% and 20% higher thermal efficiency than medium- (MiG-12 mm) and high-iron glasses (HiG-12 mm), respectively, for a peak summer day. The effect of glass thickness on thermal performance is noteworthy in glasses than in acrylic glass sheets. Low-iron content glass with 6 mm thickness has the highest thermal and optical efficiency of 63.2% and 75.65%, respectively, for the collector optimum tilt for Vellore city in Tamil Nadu, India. The results are useful in the selection of glass covers for energy-efficient solar flat plate collectors.
High-Spin Cobalt(II) Complex with Record-Breaking Anisotropy of the Magnetic Susceptibility According to Paramagnetic NMR Spectroscopy Data
Authors: Pankratova Ya. A. , Nelyubina Yu. V. , Novikov V. V. , Pavlov A. A. 
Published: February 2021

Abstract
The tetrahedral cobalt(II) complex [CoL2](HNEt3)2 (I), where L is 1,2-bis(methanesulfonamido)benzene, exhibiting the properties of a single-molecule magnet is synthesized and characterized. The electronic structure parameters of complex I are determined by paramagnetic NMR spectroscopy. They completely reproduce the results of less available methods of studying single-molecule magnets. The value of axial anisotropy of the magnetic susceptibility estimated for complex I (Δχax = 34.5 × 10–32 m3 at 20°C) is record-breaking among all transition metal complexes studied by the NMR method, which provides wide possibilities for the use of complex I as a paramagnetic label for structural biology or as a contrast agent and even a temperature sensor for medical diagnostics. The data obtained indicate the advantages of paramagnetic NMR spectroscopy as a method of investigation of the magnetic properties and electronic structures of highly anisotropic transition metal complexes, which are precursors of many functional materials.