bluuebunny/crossref_metadata_2025_split huggingface dataset:
In-Situ Calibrated Digital Process Twin Models for Resource Efficient Manufacturing
Authors: Adeniji David , Schoop Julius 
Published: August 2021

Abstract
The chief objective of manufacturing process improvement efforts is to significantly minimize process resources such as time, cost, waste, and consumed energy while improving product quality and process productivity. This paper presents a novel physics-informed optimization approach based on artificial intelligence (AI) to generate digital process twins (DPTs). The utility of the DPT approach is demonstrated for the case of finish machining of aerospace components made from gamma titanium aluminide alloy (γ-TiAl). This particular component has been plagued with persistent quality defects, including surface and sub-surface cracks, which adversely affect resource efficiency. Previous process improvement efforts have been restricted to anecdotal post-mortem investigation and empirical modeling, which fail to address the fundamental issue of how and when cracks occur during cutting. In this work, the integration of in-situ process characterization with modular physics-based models is presented, and machine learning algorithms are used to create a DPT capable of reducing environmental and energy impacts while significantly increasing yield and profitability. Based on the preliminary results presented here, an improvement in the overall embodied energy efficiency of over 84%, 93% in process queuing time, 2% in scrap cost, and 93% in queuing cost has been realized for γ-TiAl machining using our novel approach.
A Method to Predict Fatigue Life of Additively Manufactured Metallic Parts
Authors: Zhu Hanyu , Zhao Nanzhu , Patil Sandeep , Bhasin Amit , Li Wei 
Published: August 2021

Abstract
Additive manufacturing (AM) of metallic parts is rapidly evolving and the fatigue behavior of AM parts has become a significant concern in both industry and academia. In this paper, a method to predict the fatigue life of additively manufactured metallic parts is presented based on the electrical resistance measurement. The damage of the AM parts is characterized by the resistance change during the fatigue process. By combining the electrical resistance measurement with a continuum damage mechanics theory, a mathematical model is developed to predict the fatigue life of the AM samples. Fatigue tests were conducted under different loading conditions with AM 316L stainless steel samples. The result showed that the electrical resistance held steady at the beginning and increased gradually with the number of fatigue loading cycles. The resistance increased dramatically as the sample approached the fracture point, and this sudden increase can be used to indicate the beginning of fracture. By converting the electrical resistance to fatigue damage, experimental data was used to estimate parameters of the fatigue life model. By comparing the model prediction with experimental data, it is shown that the change of electrical resistance can be used to predict the fatigue life of additively manufactured metallic parts.
Friction Analysis in Needle Insertion Into Soft Tissue
Authors: Hu Yingda , Li Murong , Lei Yong 
Published: August 2021

Abstract
As one of the preoperative diagnostic methods, needle insertion is widely used for its safety and effectiveness. Recently, robotic needle insertion systems have been under active developments. Hence needle insertion experiments are essential for system verifications, in which the interactions between needle and tissue is a major focus for needle-tissue interactive models, and the friction between the needle and tissue is an important factor. In these experiments, the friction coefficient can be affected by many factors, such as insertion speed, needle-tissue deformation and contact forces. In this paper, to study and analyze the influence of various variables on friction force and friction coefficient, three variables, i.e., tissue pressure on needle, needle insertion velocity and Young’s modulus of the tissue, are systematically studied by constructing a testbed, in which the radial surface friction is converted into equivalent plane friction based on the assumption that the distribution of the normal force and friction force on the needle is uniform for the whole needle outer surface. The experimental results show that the variation range of friction coefficient is 0.122–0.341. The friction coefficient decreases with the increase of pressure and increases with the increase of velocity, while Young’s modulus have a small effect on the friction coefficient.
Prediction of Melt-Pool Characteristics in SLM Process for Ti6Al4V Using a Semi-Analytical Model
Authors: Nandi Shubhra Kamal , Kumar Rakesh , Anubhav  , Agrawal Anupam 
Published: August 2021

Abstract
Selective Laser Melting (SLM) is a powder-based layer-by-layer manufacturing technique to produce metallic customized shape components. The exceptionally high thermal gradient induces residual stress and distorts the part geometry affecting the yield quality. Computational models are instrumental in optimizing the process controls to fabricate high-quality components, and hence several such methods have been explored to simulate the thermal behavior of the process and the heat transfer in the melt-pool. Most of the practiced techniques are computationally expensive, making it infeasible to perform a parametric study. Based on closed-form exact heat conduction solution and Finite Volume Method (FVM), a pseudo-analytical thermal modeling approach has been employed to estimate the melt-pool characteristics and temperature distribution of the SLM process. A moving volumetric Gaussian heat source laser model and Green’s function have been adopted to model the heat input by conduction. The heat loss by conduction and convection has been calculated by implementing Finite Volume discretized equations on a 2-dimensional thin-walled domain with appropriate part boundary conditions. Additionally, the Alternating Direction Implicit iterative technique has been implemented for the fast convergence of the simulation. The model is used to demonstrate the influence of the process parameters and non-linear material phase change for a single-line single layer and multilayer part fabrication. The computed melt-pool dimensions and temperature distribution for varying laser-power, scanning velocity, and layer thickness for Ti6Al4V are validated with the experimental data from the literature with fair agreements.
Energy Efficient Multi-Robotic 3D Printing for Large-Scale Construction – Framework, Challenges, and a Systematic Approach
Authors: Haghighi Azadeh , Mohammed Abdullah , Wang Lihui 
Published: August 2021

Abstract
An emerging trend in smart manufacturing of the future is robotic additive manufacturing or 3D printing which introduces numerous advantages towards fast and efficient printing of high-quality customized products. In the case of the construction industry, and specifically in large-scale settings, multi-robotic additive manufacturing (i.e., adopting a team of 3D printer robots) has been found to be a promising solution in order to overcome the existing size limitations. Consequently, several research efforts regarding the development and control of such robotic additive manufacturing solutions have been reported in the literature. However, given the increasing environmental concerns, establishing novel methodologies for energy-efficient processing and planning of these systems towards higher sustainability is necessary. This paper presents a novel framework towards energy-efficient multi-robotic additive manufacturing and describes the overall challenges with respect to the energy efficiency. The energy module of the proposed framework is implemented in a simulation environment. In addition, a systematic approach for energy-aware robot positioning is introduced based on the novel concept of reciprocal energy map. The reciprocal energy map is established based on the original energy map calculated by the energy module and can be used for identifying the low energy zones for positioning and relocation of robots during the printing process.
Untethered Microrobots With Serpentine Actuators: The Role of Elastics Point Contact & Laser Beam Shape on Their Locomotion
Authors: Chowdhury Sri Sukanta , Yang Zhong , Clapacs Patrick W. , Popa Dan O. 
Published: August 2021

Abstract
FEA simulations of 7 microrobots designed from asymmetric Chevron actuators are presented with in depth analysis of their resonance behavior due to fixed, as well as elastic supports at their contact points with underlying substrate. Experimental resonance frequencies of 3 different designs identified by frequency sweep experiments, excited by a 532 nm pulse laser, are in close agreement with the simulated values. Contact stiffness is estimated by comparing simulated and experimental resonance frequencies. Both in-plane and out of plane motion due to resonance is found in all of these structures that can be used to predict the stick-slip step size (locomotion mechanism) of these robots. In addition, modeling of differential thermal expansion is conducted to optimize the laser spot size that is used to drive these microrobots. Simulations of elliptic and circular laser spots with varying size suggest that covering only the actuators of the robot is sufficient for successful actuation. Using a circular laser spot increase the thermal expansion of the overall microrobot by 3.3 nm resulting in no significant gain in step size/gait of the robotic locomotion. This finding proves that the shape and size of the laser spot are insignificant as long as the actuators are under the laser beam.
Toward Intelligent Online Scan Sequence Optimization for Uniform Temperature Distribution in LPBF Additive Manufacturing
Authors: Ramani Keval S. , Malekipour Ehsan , Okwudire Chinedum E. 
Published: August 2021

Abstract
Laser powder bed fusion (LPBF) is an increasingly popular approach for additive manufacturing (AM) of metals. However, parts produced by LPBF are prone to residual stresses, deformations, and other defects linked to nonuniform temperature distribution during the process. Several works have highlighted the important role (laser) scanning strategies, including laser power, scan speed, scan pattern and scan sequence, play in achieving uniform temperature distribution in LPBF. However, scan sequence continues to be determined offline based on trial-and-error or heuristics, which are neither optimal nor generalizable. To address these weaknesses, we present a framework for intelligent online scan sequence optimization to achieve uniform temperature distribution in LPBF. The framework involves the use of physics-based models for online optimization of scan sequence, while data acquired from in-situ thermal sensors provide correction or calibration of the models. The proposed framework depends on having: (1) LPBF machines capable of adjusting scan sequence in real-time; and (2) accurate and computationally efficient models and optimization approaches that can be efficiently executed online. The first challenge is addressed via a commercially available open-architecture LPBF machine. As a preliminary step towards tackling the second challenge, an analytical model is explored for determining the optimal sequence for scanning patterns in LPBF. The model is found to be deficient but provides useful insights into future work in this direction.
Multi-Agent-Based Self-Organizing Manufacturing Network Towards Mass Personalization
Authors: Qin Zhaojun , Lu Yuqian 
Published: August 2021

Abstract
Mass personalization is arriving. It requires smart manufacturing capabilities to responsively produce personalized products with dynamic batch sizes in a cost-effective way. However, current manufacturing system automation technologies are rigid and inflexible in response to ever-changing production demands and unforeseen internal system status. A manufacturing system is required to address these challenges with adaptive self-organization capabilities to achieve flexible, autonomous, and error-tolerant production. Within the context, the concept of Self-Organizing Manufacturing Network has been proposed to achieve mass personalization production. In this paper, we propose a four-layer system-level control architecture for Self-Organizing Manufacturing Network. This architecture has additional two layers (namely, Semantic Layer and Decision-Making Layer) on Physical Layer and Cyber Layer to improve communication, interaction, and distributed collaborative system automation. In this architecture, manufacturing resources are encapsulated as Semantic Twins to make interoperable peer communication in the manufacturing network. The interaction of Semantic Twins consolidates system status and manufacturing environment that enables multi-agent control technologies to optimize manufacturing operations and system performance.
Influence of Tool Runout on Force Measurement During Internal Void Monitoring for Friction Stir Welding of 6061-T6 Aluminum
Authors: Franke Daniel , Zinn Michael , Rudraraju Shiva , Pfefferkorn Frank E. 
Published: August 2021

Abstract
The goal of this research was to examine how altering the amount of friction stir tool eccentricity while controlling the amount of slant in the tool shoulder (drivers of oscillatory process forces) effects the generation of process force transients during sub-surface void interaction. The knowledge gained will help improve the accuracy of force-based void monitoring methods that have the potential to reduce the need for post-weld inspection. Process force transients during sub-surface void formation were examined for multiple tools with varying magnitudes of kinematic runout. The eccentric motion of the tool produced oscillations in the process forces at the tools rotational frequency that became distorted when features (flats) on the tool probe interacted with voided volumes, generating an amplitude in the force signals at three times the tool rotational frequency (for three flat tools). A larger tool eccentricity generates a larger amplitude in the force signals at the tool’s rotational frequency that holds a larger potential to create a distortion during void interaction. It was determined that once void becomes large enough to produce an interaction that generates an amplitude at the third harmonic larger than 30% of the amplitude at the rotational frequency in a weld with no interaction (amplitude solely at rotational frequency), the trailing edge of the tool shoulder cannot fully consolidate the void, i.e., it will remain in the final weld. Additionally, once the void exceeds a certain size, the amplitudes of the third harmonics saturate at 70% of the amplitude at the rotational frequency during full consolidation. The interaction between the eccentric probe and sub-surface void was isolated by ensuring any geometric imperfection in the shoulder (slant) with respect to the rotational axis was removed. The results suggest that geometric imperfections (eccentricity and slant) with respect to the tool’s rotational axis must be known when developing a void monitoring method from force transients of this nature.
Study on Non-Axisymmetric 3D Curved Surface Turning by Driven-Type Rotary Tool Synchronized With Spindle
Authors: Ishizuka Akane , Ueda Narimasa , Morimoto Yoshitaka , Hayashi Akio , Kaneko Yoshiyuki , Suzuki Naohiko 
Published: August 2021

Abstract
Since shifting to electric vehicles as a countermeasure against global warming is not always easy to complete, the hybrid car has been considered as another possible solution. However, based on the calculation of total CO2 emissions, all hybrid cars which will constitute 90% of all cars are expected to be equipped with an internal combustion engine even after 2030. Therefore, further efficiency improvement of the internal combustion engine is necessary. One of the key factors is the variable valve timing and variable lift with the 3D cam mechanism. Since conventional technology uses a complicated link mechanism and servo motor control, this leads a problem to set into small cars or motorcycles because they cannot afford to install the variable valve timing and variable lift with cam mechanism. To solve this problem, a cam shape with a three-dimensional curved surface has been proposed. In order to create this shape, the machining method for non-axisymmetric curved surface turning (NACS-Turning) is required. To build the new system, our research group has proposed a new machining method using a driven type rotary tool and a linear motor driven moving table to enable to achieve NACS-Turning. In this new system, a new tool rotation axis (B axis) is adopted to synchronize its rotational position with the rotational position of the spindle (C axis) holding the workpiece, the X1-, X2-, and Z-Axis positions in total. In this paper, the new hardware configuration is proposed to overcome the present machining accuracy.
Association between statin use and the risks of glaucoma in Australia: a 10-year cohort study
Authors: Yuan Yixiong , Wang Wei , Shang Xianwen , Xiong Ruilin , Ha Jason , Zhang Lei , Zhu Zhuoting , He Mingguang 
Published: August 2021

SynopsisIn a cohort of middle-aged and elderly Australians, we found that long-term statin use was associated with a higher risk of glaucoma onset. As to subtypes of statins, the increased risk was only found in rosuvastatin users.PurposeTo investigate the relationship between statin use and glaucoma onset in a 10-year longitudinal study.MethodsThis nested case–control study was based on data from a large-scale cohort of Australians aged over 45 years old. Medication exposure was identified by claims records from the Pharmaceutical Benefits Scheme during the follow-up period (2009–2016). The onset of glaucoma was defined as the people with at least three claims of antiglaucoma medications. Controls matched by age, gender and cardiovascular diseases were selected from participants without prescription of antiglaucoma medications. A conditional logistic regression model was used to assess the association between statin use and glaucoma onset.ResultsThe proportion of statin users was higher in the case group (40.5%) than that in the control group (38.4%). After adjusting for baseline characteristics and longitudinal claims records, statin use was not associated with glaucoma onset (OR 1.04, 95% CI 0.97 to 1.11). However, an increased risk of glaucoma onset was observed in participants with a longer duration of statin use (>3 years vs <1 year: OR 1.12, 95% CI 1.04 to 1.21). With respect to specific types of statins, participants taking rosuvastatin were more likely to suffer from glaucoma (OR 1.11, 95%CI 1.01 to 1.22). The use of other statins was not significantly associated with glaucoma onset.ConclusionsLong-term statin use was found to be associated with a higher risk of glaucoma onset in this study. Regarding specific types of statins, the increased risk of glaucoma onset was only observed in users of rosuvastatin.
Charles Bonnet syndrome in patients with Stargardt disease: prevalence and risk factors
Authors: Dhooge Patty P A , Teunisse Rob J , Liefers Bart , Lambertus Stanley , Bax Nathalie M , Hoyng Carel B , Cruysberg Johannes R M , Klevering B Jeroen 
Published: August 2021

AimsTo describe the prevalence of the Charles Bonnet syndrome (CBS) and search for potential CBS risk factors in a Dutch Stargardt disease (STGD1) cohort.MethodsEighty-three patients with STGD1 were screened for CBS. They underwent a full eye examination. All patients completed the social functioning domain of the 36-Item Short Form Health Survey questionnaire. Participants suspected of CBS were interviewed to further evaluate their visual hallucinations.ResultsCBS prevalence was 8.4%. Six out of seven patients with CBS were women. CBS was not associated with age (p=0.279, Mann-Whitney). Patients with CBS had a significant lower social functioning score (p<0.05, Mann-Whitney). All seven patients with CBS were in the category of vision impairment (visual acuity <6/12, but ≥3/60). Moreover, first hallucinations manifested after a drop in visual acuity. The retinal atrophic area of the worst eye tended to be lower in the CBS group (range 0.11–9.86 mm2) as compared with controls (range 0–180 mm2). There was no relation between the position of the scotoma and the location of the visual hallucinations.ConclusionThe relative high CBS prevalence in STGD1 suggests that CBS may be more prevalent in younger ophthalmic patients than currently presumed. In this specific group of patients, we established social isolation and acquired vision impairment as risk factors for CBS. There was a female preponderance among patients with CBS. Age and retinal pigment epithelium atrophy were not identified as significant risk factors. We should actively diagnose CBS in patients of any age who fulfil the criteria for the category vision impairment, especially in cases where social isolation is suspected.
Trends in the co-use of alcohol and tobacco among Japanese adolescents: periodical nationwide cross-sectional surveys 1996–2017
Authors: Fujii Maya , Kuwabara Yuki , Kinjo Aya , Imamoto Aya , Jike Maki , Otsuka Yuichiro , Itani Osamu , Kaneita Yoshitaka , Minobe Ruriko , Maesato Hitoshi , Higuchi Susumu , Yoshimoto Hisashi , Kanda Hideyuki , Osaki Yoneatsu 
Published: August 2021

ObjectivesThis study aimed to assess trends in the prevalence of alcohol use depending on smoking behaviours and that of smoking depending on drinking behaviours among Japanese adolescents.DesignThis was a retrospective study using Japanese school-based nationwide surveys conducted between 1996 and 2017.SettingSurveyed schools, both junior and senior high schools, considered representative of the entire Japanese population, were sampled randomly.ParticipantsWe enrolled 11 584–64 152 students from 179 to 103 schools yearly. They completed a self-reported and anonymous questionnaire on smoking and drinking behaviour.ResultsSince 1996, the prevalence of alcohol use and smoking among adolescents decreased in each survey (p<0.01). The prevalence of alcohol use in the non-smokers group was 29.0% in 1996 and 4.0% in 2017, and in the smokers group, it was 73.3% in 1996 and 57.4% in 2017. The reduction rate (the difference in prevalence between 1996 and 2017 divided by the prevalence in 1996) was 0.86 in the non-smokers group and 0.22 in the smokers group. The prevalence of smoking in the non-drinkers group was 6.7% in 1996 and 0.7% in 2017, while that in the drinkers group was 32.5% in 1996 and 18.9% in 2017. The reduction rate was 0.90 in the non-drinkers group and 0.42 in the drinkers group. Therefore, downward trends differed among the groups. In a subanalysis of senior high school students, we divided students into three groups according to their intention to pursue further education. Between 1996 and 2017, there was a consistent difference in the prevalence of alcohol use and smoking among these groups.ConclusionsAlcohol use and smoking among Japanese adolescents seem to have reduced. However, certain groups showed poor improvements, and health risk behaviour disparity exists, which may widen further. We need to focus on high-risk groups and implement appropriate measures or interventions accordingly.