bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Support Vector Regression and Genetic Algorithm to Reduce Web Warping in Flexible Roll-Forming Process
Authors: Woo Young Yun , Ko Dae-Cheol , Lee Taekyung , Kim Yangjin , Kim Ji Hoon , Moon Young Hoon 
Published: October 2020

AbstractIn a flexible roll-forming process, a metal blank is incrementally deformed into the desired shape with a variable cross-sectional profile by passing the blank through a series of forming rolls. Because of the combined effects of process and material parameters on the quality of the roll-formed product, the approaches used to optimize the roll-forming process have been largely based on experience and trial-and-error methods. Web warping is one of the major shape defects encountered in flexible roll forming. In this study, an optimization method was developed using support vector regression (SVR) and a genetic algorithm (GA) to reduce web warping in flexible roll forming. An SVR model was developed to predict the web-warping height, and a response surface method was used to investigate the effect of the process parameters. In the development of these predictive models, three process parameters—the forming-roll speed condition, leveling-roll height, and bend angle—were considered as the model inputs, and the web-warping height was used as the response variable. The GA used the web-warping height and the cost of the roll-forming system as the fitness function to optimize the process parameters of the flexible roll-forming process. When the flexible roll-forming process was carried out using the optimized process parameters, the obtained experimental results indicated a reduction in web warping. Hence, the feasibility of the proposed optimization method was confirmed.
Optimal Design of Fixture Layout for Compliant Part With Application in Ship Curved Panel Assembly
Authors: Du Juan , Liu Changhui , Liu Jianfeng , Zhang Yansong , Shi Jianjun 
Published: October 2020

AbstractIn a ship assembly process, a large number of compliant parts are involved. The ratio of the part thickness to the length or the width is typically 0.001–0.012. Fixture design is a critical task in the ship assembly process due to its impact on the deformation and dimensional variation of the compliant parts. In current practice, fixtures are typically uniformly distributed under the part to be assembled, which is non-optimal, and large dimensional gaps may occur during assembly. This paper proposed a methodology for the optimal design of the fixture layout in the ship assembly process by systematically integrating direct stiffness method and simulated annealing algorithm, which aims to minimize dimensional gaps along the assembly interface to further improve the quality and efficiency of seam welding. The case study shows that the proposed method significantly reduced the dimensional gaps of the compliant curved panel parts in a ship assembly process.
Deep Learning-Based Data Fusion Method for In Situ Porosity Detection in Laser-Based Additive Manufacturing
Authors: Tian Qi , Guo Shenghan , Melder Erika , Bian Linkan , Guo Weihong “Grace” 
Published: October 2020

Abstract
Laser-based additive manufacturing (LBAM) provides unrivalled design freedom with the ability to manufacture complicated parts for a wide range of engineering applications. Melt pool is one of the most important signatures in LBAM and is indicative of process anomalies and part defects. High-speed thermal images of the melt pool captured during LBAM make it possible for in situ melt pool monitoring and porosity prediction. This paper aims to broaden current knowledge of the underlying relationship between process and porosity in LBAM and provide new possibilities for efficient and accurate porosity prediction. We present a deep learning-based data fusion method to predict porosity in LBAM parts by leveraging the measured melt pool thermal history and two newly created deep learning neural networks. A PyroNet, based on Convolutional Neural Networks, is developed to correlate in-process pyrometry images with layer-wise porosity; an IRNet, based on Long-term Recurrent Convolutional Networks, is developed to correlate sequential thermal images from an infrared camera with layer-wise porosity. Predictions from PyroNet and IRNet are fused at the decision-level to obtain a more accurate prediction of layer-wise porosity. The model fidelity is validated with LBAM Ti–6Al–4V thin-wall structure. This is the first work that manages to fuse pyrometer data and infrared camera data for metal additive manufacturing (AM). The case study results based on benchmark datasets show that our method can achieve high accuracy with relatively high efficiency, demonstrating the applicability of the method for in situ porosity detection in LBAM.
Synthesis and Application of a Single Degree-of-Freedom Six-Bar Linkage With Mixed Exact and Approximate Pose Constraints
Authors: Zhao Xiong , Yu Chennan , Chen Jianneng , Sun Xincheng , Ye Jun , Chen Zhiwei , Zhou Qiaojun 
Published: October 2020

Abstract
Existing research on synthesis methods for single degree-of-freedom (DOF) six-bar linkages mainly include four or five exact poses. However, an ideal trajectory cannot be synthesized using only five exact poses, thus, it is necessary to introduce additional poses to constrain the trajectory. If more exact poses are introduced, then the linkage may have no solution. Therefore, the constraints of the approximate pose are considered to make the trajectory conform to the desired trajectory. This paper successfully introduces mixed poses into a six-bar linkage, based on Z (Z &lt; 5) exact poses and K approximate poses of a given error range, and a new synthesis method for single DOF six-bar linkages is proposed. The solution domain of the linkages synthesized by this method is wide and can be adjusted by controlling the error of the approximate poses, which reduces the difficulty of selecting the solution, ensures theoretical feasibility, and enables the trajectory of the final linkage to more closely match the ideal trajectory. Finally, for the coordinated training of multiple joints in human limbs, a rehabilitation device is designed based on the above six-bar linkage, and a prototype is developed and tested. The test results reveal the accuracy of the proposed method and the effectiveness of rehabilitation training.
Analytical Solution for Temperature Distribution in a Multilayer Body With Spatially Varying Convective Heat Transfer Boundary Conditions on Both Ends
Authors: Zhou Long , Parhizi Mohammad , Jain Ankur 
Published: October 2020

Abstract
Analytical modeling of thermal conduction in a multilayer body is of practical importance in several engineering applications such as microelectronics cooling, building insulation, and micro-electromechanical systems. A number of analytical methods have been used in past work to determine multilayer temperature distribution for various boundary conditions. However, there is a lack of work on solving the multilayer thermal conduction problem in the presence of spatially varying convective heat transfer boundary condition. This paper derives the steady-state temperature distribution in a multilayer body with spatially varying convective heat transfer coefficients on both ends of the body. Internal heat generation within each layer and thermal contact resistance between layers are both accounted for. The solution is presented in the form of an eigenfunction series, the coefficients of which are shown to be governed by a set of linear, algebraic equations that can be easily solved. Results are shown to be in good agreement with numerical simulation and with a standard solution for a special case. The model is used to analyze heat transfer for two specific problems of interest involving spatially varying convective heat transfer representative of jet impingement and laminar flow past a flat plate. In addition to enhancing the theoretical understanding of multilayer heat transfer, this work also contributes toward design and optimization of practical engineering systems comprising multilayer bodies.
Droplet Evaporation of Cu–Al2O3 Hybrid Nanofluid Over Its Residue and Copper Surfaces: Toward Developing a New Analytical Model
Authors: Siddiqui Farooq Riaz , Tso Chi Yan , Fu Sau Chung , Qiu Huihe , Chao Christopher Y. H. 
Published: October 2020

Abstract
Droplet evaporation-based cooling techniques, such as the spray cooling, give high heat transfer rates by utilizing latent energy and are usually preferred in thermal applications. However, with the significant rise in heat dissipation levels for high heat flux devices, these devices cannot be thermally managed due to the limited cooling capacity of existing thermal fluids. In this paper, we report the evaporation of the Cu–Al2O3 hybrid nanofluid (HNF) droplet on a copper surface as well as its own residue surface, developed from the evaporation of the first Cu–Al2O3 HNF droplet. As the main novelty, we identify the critical residue size and investigate the residue size effect, above and below the critical residue size, on evaporation rate of the succeeding Cu–Al2O3 HNF droplet resting over a residue surface. We also develop a new analytical model to estimate the Cu–Al2O3 HNF droplet evaporation rate and compare our results with other existing models. The results show that the Cu–Al2O3 HNF droplet gives 17% higher evaporation rate than a water droplet on a copper surface. Also, the evaporation rate of the Cu–Al2O3 HNF droplet on a residue surface sharply increases by 106% with increasing residue size up to the critical residue size. However, further increasing the residue size above its critical value has a negligible effect on the droplet evaporation rate. Moreover, the evaporation rate of the Cu–Al2O3 HNF droplet on its residue surface is enhanced up to 104% when compared to a copper surface.
Experimental Thermal Study of Ice Slurry Production System Equipped With Direct Contact Heat Exchanger and Spiral Nozzle
Authors: Zhang Yaokang , Su Lin , Xu Zhaoyang , Dong Kaijun , Li Jing 
Published: October 2020

Abstract
For the direct contact ice slurry production system, the obstacles of ice blockage in the nozzle, enormous refrigerant charge, and refrigerant-water separation restrict its commercial application. In this paper, a novel direct contact ice slurry production system is proposed to overcome these obstacles. In this novel system, the horizontal PVC pipe with the spiral nozzle is designed as a direct contact ice slurry generator to avoid ice blockage in the nozzle. The two-phase RC318 is utilized as the system refrigerant. In order to investigate the ice production performance of this novel system, the effects of compressor rotational speed, internal water flowrate, and initial system pressure on ice production performance are experimentally studied, and a lump model is established. The results show that the ice production performance is mainly affected by the compressor rotational speed, but scarcely affected by the internal water flowrate. However, large ice blocks are formed at small internal water flowrate. Besides, the lump model is considered to be able to predict the water temperature. Furthermore, the sinking of the liquid refrigerant exits under the higher initial system pressure, but it can be avoided by reducing the initial system pressure.
Pulsatile Aortic Blood Flow—A Critical Assessment of Boundary Conditions
Authors: Fuchs Alexander , Berg Niclas , Prahl Wittberg Lisa 
Published: October 2020

Abstract
Patient specific (PS) blood flow studies have become popular in recent years but have thus far had limited clinical impact. This is possibly due to uncertainties and errors in the underlying models and simulations setup. This study focuses on the sensitivity of simulation results due to in- and outflow boundary conditions (BCs). Nine different inlet- and seven different outlet BCs were applied to two variants of a healthy subject's thoracic aorta. Temporal development of the flow is essential for the formation and development of helical/spiraling flow where the commonly observed clockwise helical motion may change direction during the heart-cycle. The sensitivity to temporal and spatial variations in the inlet conditions is significant both when expressed in terms of mean and maximal wall shear stress (WSS) and its different averaged variables, e.g., time-averaged WSS (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT). The simulation results are highly sensitive to BC. For example, the maximal WSS may vary over three-orders of magnitude (1–1000 Pa) depending on particular combinations of BCs. Moreover, certain formulations of outlet BCs may be inconsistent with the computed flow field if the underlying assumptions of the space–time dependence are violated. The results of this study show that computational fluid dynamics (CFD) simulations can reveal flow details that can enhance understanding of blood flows. However, the results also demonstrate the potential difficulties in mimicking blood flow in clinical situations.
Investigation on Tripping in Magnetic Generator in Steam-Assisted Gravity Drainage Wells Based on Numerical Simulation
Authors: Chen Yong , Su An Qiao , Zhang Jin Tao , Jia Zong Sheng 
Published: October 2020

AbstractMagnetic Guidance Technology can meet the precise measurement requirements when drilling steam-assisted gravity drainage (SAGD) oil wells. Magnetic generator is a key part in the Magnetic Guidance Technology. When magnetic generator is tripped into horizontal well, pump pressure and passing capacity of the magnetic source generator in the curved section need to be analyzed. So, a mathematical model of tripping in the magnetic generator is established. If curvature radius, deviation angle, and friction factor are known, the forces acting on the magnetic generator in different positions could be calculated. The finite element (FE) results show that: (1) with depth increasing in the curved section, the equivalent stress on the magnetic generator increases in a fluctuating manner, the contact area, friction drag, and energy loss increase. (2) The greater the hole curvature, the greater tripping in force and the higher pump pressure are needed. The lower friction coefficient is favorable to tripping in the magnetic generator. (3) The friction between the magnetic generator and tubing wall in the horizontal section is much less than that in the curved section. Field applications have shown that the maximum downforce is close to the result of finite element analysis. The research results provide a reasonable reference basis for smooth running of magnetic source generators with different trajectory conditions.
Lattice Discrete Particle Modeling of Size Effect in Slab Scratch Tests
Authors: Han Lin , Pathirage Madura , Akono Ange-Therese , Cusatis Gianluca 
Published: October 2020

AbstractFor a long time, geomechanicians have used scratch tests to characterize the compressive behavior and hardness of rocks. In recent years, this test has regained popularity in the field of mechanics, especially after a series of publications that highlighted the potential capability of the scratch test to determine the fracture properties of quasi-brittle materials. However, the complex failure mechanisms observed experimentally in scratch tests led to scientific debates and, in particular, raised the question of the size effect. This article intends to provide a better understanding of the problem by using numerical tools and fracture mechanics considerations. To narrow the investigation area, this study focuses on slab scratch tests of quasi-brittle materials and adopts two different numerical methods: (i) the lattice discrete particle model (LDPM) that includes constitutive laws for cohesive fracturing, frictional shearing, and nonlinear compressive behavior, and (ii) the meshless method based on Shepard function and partition of unity (MSPU) implementing linear elastic fracture mechanics (LEFM). The numerical results are further analyzed through Bažant’s size effect law (SEL) with an appropriate mixed-mode fracture criterion. Fracture properties are then calculated and compared to the results of typical notched three-point bending tests. The results show that mixed-mode fracture considerations are of paramount importance in analyzing the fracture process and size effect of scratch tests.
Barriers to Implementation of Physical Activity in Danish Public Schools
Authors: Koch Sofie , Troelsen Jens , Cassar Samuel , Pawlowski Charlotte Skau 
Published: October 2020

Purpose: In 2014, the Danish Government introduced a new public school reform, which included implementation of 45 min of daily physical activity (PA) within the academic classroom curriculum. The purpose of the present study was to explore school staff’s perceived barriers to implementation of a national PA policy. Method: A mixed-methods approach using a questionnaire and semistructured interviews was conducted. A total of 198 teachers and 26 school management team members (principals, deputy principals, and leading teachers) from 31 schools completed a questionnaire, and 11 school management team members were interviewed. The socioecological model was used as a theoretical framework to examine the results. Results: A total of 15 different barriers were identified and reflected within all levels of the socioecological model. Facilities, motivation, and time were the most prominent barriers identified. Conclusion: Development and deployment of a national PA policy needs to be done in cooperation with consumers from all levels within the socioecological model to ensure successful implementation.
In Vitro
Activity of Cefepime-Zidebactam, Ceftazidime-Avibactam, and Other Comparators against Clinical Isolates of
Enterobacterales
, Pseudomonas aeruginosa, and Acinetobacter baumannii: Results from China Antimicrobial Surveillance Network (CHINET) in 2018
Authors: Yang Yang , Guo Yan , Yin Dandan , Zheng Yonggui , Wu Shi , Zhu Demei , Hu Fupin 
Published: October 2020

This study evaluated the
in vitro
activity of cefepime-zidebactam in comparison with that of ceftazidime-avibactam and other comparators against clinically significant Gram-negative bacillus isolates. A total of 3,400 nonduplicate Gram-negative clinical isolates were collected from 45 medical centers across China in the CHINET Program in 2018, including
Enterobacterales
(
n
= 2,228),
Pseudomonas aeruginosa
(
n
= 657), and
Acinetobacter baumannii
(
n
= 515).
Intracranial injuries on computed tomography head scans in infants investigated for suspected physical abuse: a retrospective review
Authors: Daley Helen , Smith Hilary , McEvedy Samantha , King Rachel , Andrews Edward , Hawkins Faye , Guppy Nicole , Kiryazova Todorka , Macleod Rebecca , Blake Emma , Harrison Rachael 
Published: October 2020

BackgroundUK national guidelines recommend that investigation of infants (aged <12 months) with suspected physical abuse should always include CT head scans. Such imaging carries small but recognised risks from radiation exposure. Studies report a range of yields for occult intracranial injuries in suspected physical abuse.AimsTo report the yield of intracranial injuries on CT head scans carried out for suspected physical abuse in infants, compare yields for those presenting with or without signs of head injury and to describe selected clinical and radiological features.MethodsA retrospective cross-sectional review of case records of infants undergoing skeletal survey for suspected physical abuse in Wessex, England. The main outcome measure was yield of intracranial injuries on CT head scan.ResultsIn total, n=363 CT head scans were included (n=275 aged <6 months). The overall yield of intracranial injury was 37 (10%). Among 68 infants presenting with neurological signs or skull fractures, yield was 36 (53%) compared with just 1 (0.34%) of 295 without neurological signs or skull fractures. This one intracranial injury was found to be consistent with an accidental fall. Scalp injury was the only additional clinical feature associated with intracranial injury.ConclusionIn suspected physical abuse, CT head scans should be carried out in infants who present with neurological signs, skull fractures or scalp injuries. However, in balancing potential risks and benefits, we question the value of performing a CT head scan in every infant investigated for suspected physical abuse.
The relationships between rugby union, and health and well-being: a scoping review
Authors: Griffin Steffan A , Panagodage Perera Nirmala Kanthi , Murray Andrew , Hartley Catherine , Fawkner Samantha G , P T Kemp Simon , Stokes Keith A , Kelly Paul 
Published: October 2020

ObjectiveTo scope the relationships between rugby union, and health and well-being.DesignScoping review.Data sourcesPublished and unpublished reports of any age, identified by searching electronic databases, platforms and reference lists.MethodsA three-step search strategy identified relevant published primary, secondary studies and grey literature, which were screened usinga prioriinclusion criteria. Data were extracted using a standardised tool, to form (1) a numerical analysis and (2) a thematic summary.Results and discussion6658 records were identified, and 198 studies met the inclusion criteria. All forms of rugby union can provide health-enhancing physical activity (PA). ‘Non-contact’ and wheelchair rugby in particular provide a wide range of physical and mental health and well-being benefits. The evidence is either mixed or unclear in relation to ‘contact’ rugby union and its effects on a range of physical health domains. Injury and concussion incidence rates are high for contact rugby union relative to other sports.ConclusionsA wide range of stakeholders as well as existing and potential participants can use this information to make a more informed decision about participating in and promoting rugby union as a health-enhancing activity. Industry and policy-makers can use this review to inform policies and strategies that look to increase participation rates and use rugby union as a vehicle to contribute positively to population health. Further research understanding rugby union’s contribution to PA as well as to muscle-strengthening and balance is indicated, as well as research examining more health and well-being outcomes across more diverse cohorts.