bluuebunny/crossref_metadata_2025_split huggingface dataset:
Significance of Workpiece Conductivity on Resistance Spot Welding Process Map
Authors: Wu Xin , Du Jingtao , Cai Wayne 
Published: November 2019

Abstract
Resistance spot welding (RSW) is a sheet metal welding process with broad applications, known to be more suitable for low-conductive materials, such as steels, due to concentrated and steady-state heat generation and retention at the metal interface. However, for high conductive metals such as copper, conventional welding processes in resistance spot welding has not been successful. This paper provides a comparative study of resistance welding among steel, aluminum and copper through mechanistic analyses, i.e., analytical solutions calibrated by finite element analyses. It is found when lower conductivity metals, such as steels, are welded, the applied energy can be more concentrated on the interfaces, and the heat dissipation is relatively slow, so that a close to steady-state welding condition can be reached that provides a wide and robust operation window. For welding highly conductive metals having similar melting temperature as that of electrode, the process window becomes much narrower or does not always exist without additional conditioning of materials, design or the welding processes. The physics of RSW process is analyzed based on energy equilibrium, and a new concept of pulse welding process is proposed as a required operation mode for welding copper during temperature ramping up period and prior to electrode melting. A new type of welding limit diagram (WLD) is constructed that contains three welding limit curves (WLC) for nugget formation, and the transient region. The newly constructed WLD allows a clear distinction between welding low- and high-conductive metals, and provides new understanding and a theoretical guidance for widening the weldability window.
Ultrafast Laser Applications in Manufacturing Processes: A State of the Art Review
Authors: Lei Shuting , Zhao Xin , Yu Xiaoming , Hu Anming , Vukelic Sinisa , Jun Martin B. G. , Joe Hang-Eun , Yao Y. Lawrence , Shin Yung C. 
Published: November 2019

Abstract
With the invention of chirped pulse amplification for lasers in the mid-1980s, high power ultrafast lasers entered into the world as a disruptive tool, with potential impact on a broad range of application areas. Since then, ultrafast lasers have revolutionized laser-matter interaction and unleashed their potential applications in manufacturing processes. With unprecedented short pulse duration and high laser intensity, focused optical energy can be delivered to precisely defined material locations on a time scale much faster than thermal diffusion to the surrounding area. This unique characteristic has fundamentally changed the way laser interacts with matter and enabled numerous manufacturing innovations over the past few decades. In this paper, an overview of ultrafast laser technology with an emphasis on femtosecond laser is provided first, including its development, type, working principle, and characteristics. Then ultrafast laser applications in manufacturing processes are reviewed, with a focus on micro/nano machining, surface structuring, thin film scribing, machining in bulk of materials, additive manufacturing, bio manufacturing, super high resolution machining, and numerical simulation. Both fundamental studies and process development are covered in this review. Insights gained on ultrafast laser interaction with matter through both theoretical and numerical research are summarized. Manufacturing process innovations targeting various application areas are described. Industrial applications of ultrafast laser based manufacturing processes are illustrated. Finally, future research directions in ultrafast laser based manufacturing processes are discussed.
Corrective Maintenance Scheduling for Stochastic Manufacturing System by Online Task Allocation Method
Authors: Zhu Cheng , Yu Tian , Chang Qing , Arinez Jorge 
Published: November 2019

Abstract
Disruption events such as machine random failures significantly impact the throughput of the line. Maintenance actions could restore the machines to certain health levels. A real-time scheduling of corrective maintenance (CM) is critical to improve the machines’ performance, hence to improve overall system productivity and quality. Due to the limited quantity of technicians or robots in manufacturing system, when, where and assign what type of maintenance is a complicated decision to make. A proper strategy to assign CM can greatly reduce permanent production lost, resource and energy consumption. In this paper, an online task allocation (OTA) method is provided to solve the assignment of CM for a stochastics serial production line. Case study is given to demonstrate the effectiveness of OTA method in assigning CM.
Transient Liquid Phase Bonding of Inconel 718 With Ni and BNi-2 Nano-Braze Materials
Authors: Bridges Denzel , Hu Anming , Xu Raymond 
Published: November 2019

Abstract
Ni nanoparticles were successfully used to join Inconel 718 via transient liquid phase (TLP) bonding in a vacuum environment. Ni nanoparticles of 20 nm, 29 nm, and 41 nm in diameter were synthesized by controlling the reducing agent injection rate and joined at up to 1050 °C and heating rate 5–15 °C/min. Based on the Gibbs-Thomson equation and surface melting models, joining using Ni nanoparticles occurs due to competing solid-state sintering and surface melting processes. It was found that faster heating rate; higher maximum bonding temperature, and larger particle size resulted in higher bonding strength. Using a faster heating rate suppresses the amount of solid-state particle-particle sintering that occurs at lower temperatures, where particle-Inconel 718 joining is less active. The suppression of particle-particle sintering as a function of particle diameter is also discussed. The maximum bonding strength achieved is 243 MPa. The fracture surface for Ni nanoparticle-bonded joints demonstrated intergranular fracture (low strength joints) and a combination of cleavage and microvoid coalescence (high strength joints).
The Effects of Laser-Assisted Ultrasonic Nanocrystal Surface Modification on 3D-Printed Ti-6Al-4V Alloy
Authors: Zhang Hao , Liu Jun , Dong Yalin , Ye Chang 
Published: November 2019

Abstract
In this paper, 3D-printed Ti-6Al-4V (Ti64) alloy, a hard-to-deform alloy with poor surface finish and high porosity was processed by an innovative technique, laser-assisted ultrasonic nanocrystal surface modification (LA-UNSM). The localized thermal effect of continuous laser decreases the flow stress of the alloy effectively. The effects of LA-UNSM on surface finish, microstructure, and surface hardness were investigated and compared with traditional UNSM treated samples. It is found that much smoother and harder surface was obtained after LA-UNSM. In addition, LA-UNSM also led to a thicker plastically-affected layer compared with UNSM process only. It is found that the LA-UNSM is a very efficient post-processing technique for 3D-printed alloys since it makes the thermal and mechanical effects work synergistically and energy-efficiently.
Automated Measuring Planning for On-Machine Measurement and Re-Machining Process
Authors: Murase Motoaki , Nishida Isamu , Sato Ryuta , Shirase Keiichi 
Published: November 2019

Abstract
On-machine measurement (OMM) is introducing to Numerical Control (NC) machine tools. By the OMM, a workpiece is measured on the machine tool (i.e., without loading and unloading), so OMM can reduce the setup time and positioning error for reloading a workpiece. OMM is used for the process control during machining because it is still difficult to suppress the machining error caused by the cutting process such as the tool deflection, the tool wear and the heat deformation during machining. There are several approaches to on-machine measurement, including non-contact measurements using a laser displacement sensor or imaging equipment and contact measurements using a touch probe. However, to conduct OMM with a touch probe it is necessary to generate an NC program by operators. Moreover, for the process control and monitoring, the information of machining process should be considered in the measuring plan.
For process control, measurement of a region that affects machining in the next process should be conducted during the machining process (i.e., after the machining of that region). Furthermore, when some machining abnormality that affects product quality occurs during the machining process, the abnormality should be detected and measured at an early stage to avoid unnecessary machining.
This study aims to realize the automation of planning for on-machine measurement, where measurement is conducted at the necessary time during the machining process based on process planning for the early detection of machining abnormality. Furthermore, when a machining abnormality is detected based on the measurement results, the proposed system automatically judges whether to stop machining or to re-machine the affected region.
Formation of Micro-/Nano-Surface Structures on Stainless Steel by Ultrafast Lasers
Authors: Li Kewei , Zhao Xin 
Published: November 2019

Abstract
Surface morphology is a critical factor to determine the surface functionality. Ultrafast pulsed laser is a powerful tool to induce multi-scale surface structures on different materials, and thus control their functionalities. This paper presents an experimental study on the micro/nano-scale surface structure formation by femtosecond laser irradiation on stainless steel. The effects of laser fluence, effective pulse number per spot, and repetition rate on the structure morphology and dimension are studied. By controlling the laser parameters, four different types of structures are obtained: (1) laser-induced periodic surface structrues (LIPSS), (2) microgrooves covered by LIPSS, (3) microgrooves/micro-holes covered by LIPSS, and (4) irregular microstructures. The formation dynamics and mechanisms of different structures are investigated.
Effect of Cooling Modes on Microstructure and Mechanical Properties of Cr18Ni8Mo2Si Cladding to 40Cr by Laser Cladding Technology
Authors: Xu Mingsan , Liu Simo , Mei Mingliang , Li Bingbing 
Published: November 2019

Abstract
Laser cladding is a new technology to clad metallic material to substrate. The objective of this research is to find optimized process parameters such as preheating temperature of substrate, laser power, scanning speed, spot diameter for cladding Cr18Ni8Mo2Si on 40Cr substrate. Moreover, effects of different cooling modes, cooling in temperature control box or natural environment were studied. Orthogonal experiments are used to find optimized parameters and better cooling strategy. Experimental results are analyzed through measurements of residual stress, micro-hardness, and metallic microstructure. It was observed that parts cooling in temperature control box show better qualities: smaller residual stress, less cracks or other structural defects, better microstructure, and better bonding effect. This research provides a guideline for further researches in temperature control of laser cladding and expands application to rotary die cutting machine.
Chatter Prediction for Face Milling Process of Workpieces With Variable Stiffness
Authors: Li Guilong , Du Shichang , Huang Delin , Zhao Chen , Deng Yafei 
Published: November 2019

Abstract
In face milling process, the cutting chatter induced by unsuitable processing parameters could lead to tremendous damage to machine tools and loss of machined surface quality. Therefore, as one of the most effective and efficient methods to avoid chatter, the stability lobe diagram (SLD) has received continuous concern from researchers. Since the dynamic cutting forces are definitely dependent on the tool path and the stiffness distribution of the workpiece, the exact interaction between the milling cutter and the workpiece should be taken into consideration for chatter prediction. However, most related researches have been focused on the dynamic modeling of the spindles and machine tools, regardless of the characteristics of workpieces. To overcome this limitation, an analytical method is proposed to predict the milling chatter for workpieces with variable stiffness. Firstly, a dynamic model for the general milling process is established. Secondly, the cutting insert engagement is determined based on the stiffness characteristic of the workpieces and the cutting path of the milling cutter. At last, the SLD applicable to workpieces with variable stiffness is constructed, and a case study of an engine block shows that the proposed method is valid.
Central Activation Ratio Is a Reliable Measure for Gluteal Neuromuscular Function
Authors: Gilfeather Daniel , Norte Grant , Ingersoll Christopher D. , Glaviano Neal R. 
Published: November 2019

Context: Central activation ratio (CAR) is a common outcome measure used to quantify gross neuromuscular function of the quadriceps using the superimposed burst technique, yet this outcome measure has not been validated in the gluteal musculature. Objective: To quantify gluteus medius (GMed) and gluteus maximus (GMax) CAR in a healthy population and evaluate its validity and reliability over a 1-week period. Design: Descriptive. Setting: Laboratory. Patients or Other Participants: A total of 20 healthy participants (9 males and 11 females; age 22.2 [1.4] y, height 173.4 [11.1] cm, mass 84.8 [25.8] kg) were enrolled in this study. Interventions: Participants were assessed at 2 sessions, separated by 1 week. Progressive electrical stimuli (25%, 50%, 75%, and 100%) were delivered to the GMed and GMax at rest, and 100% stimuli were delivered during progressive hip abduction and extension contractions (25%, 50%, 75%, and 100% maximal voluntary isometric contraction). Main Outcome Measures: GMed and GMax CAR, and hip abduction and hip extension maximal voluntary isometric contraction torque. Line of best fit and coefficient of determination (r2) were used to assess the relationship between torque output and CAR at varying levels of stimuli. Intraclass correlation coefficients, ICCs(3,k), were used to assess the between-session reliability. Results: GMed CAR was 96.1% (3.4%) and 96.6% (3.2%), on visits 1 and 2, respectively, whereas GMax CAR was 86.5% (7.5%) and 87.2% (10.7%) over the 2 sessions. A third-order polynomial demonstrated the best line of fit between varying superimposed burst intensities at rest for both GMed (r2 = .156) and GMax (r2 = .602). Linear relationships were observed in the CAR during progressive contractions with a maximal superimposed burst, GMed (r2 = .409) and GMax (r2 = .639). Between-session reliability was excellent for GMed CAR, ICC(3,k) = .911, and moderate for GMax CAR, ICC(3,k) = .704. Conclusion: CAR appears to be an acceptable measure of GMed and GMax neuromuscular function in healthy individuals. Gluteal CAR measurements are reliable measures over a 1-week test period.
On the cosmological models with matter creation
Authors: Ivanov Rossen I. , Prodanov Emil M. 
Published: November 2019

AbstractThe matter creation model of Prigogine–Géhéniau–Gunzig–Nardone is revisited in terms of a redefined creation pressure which does not lead to irreversible adiabatic evolution at constant specific entropy. With the resulting freedom to choose a particular gas process, a flat FRWL cosmological model is proposed based on three input characteristics: (i) a perfect fluid comprising of an ideal gas, (ii) a quasi-adiabatic polytropic process, and (iii) a particular rate of particle creation. Such model leads to the description of the late-time acceleration of the expanding Universe with a natural transition from decelerating to accelerating regime. Only the Friedmann equations and the laws of thermodynamics are used and no assumptions of dark energy component is made. The model also allows the explicit determination as functions of time of all variables, including the entropy, the non-conserved specific entropy and the time the accelerating phase begins. A form of correspondence with the dark energy models (quintessence, in particular) is established via the Om diagnostics. Parallels with the concordance cosmological $$\Lambda $$ΛCDM model for the matter-dominated epoch and the present epoch of accelerated expansion are also established via slight modifications of both models.
Improved dynamic multiparty quantum direct secret sharing protocol based on generalized GHZ states to prevent collusion attack
Authors: Yang Chun-Wei , Tsai Chia-Wei 
Published: November 2019

In 2018, Song et al. [Quantum Inf. Process 17, 244 (2018)] proposed a dynamic quantum direct secret sharing (DQDSS) protocol based on generalized GHZ states. However, this protocol is vulnerable to a security problem, known as the collusion attack, using which the dishonest agents can collude to reveal the master key without collaborating with other agents. This security problem, if unaddressed, can prevent the protocol from providing the secret sharing function. Therefore, this study proposes an improved DQDSS protocol to address the security problem in Song et al.’s DQDSS protocol. The proposed DQDSS protocol is resistant to the collusion attack and various other common attacks. Furthermore, the advantages of Song et al.’s DQDSS protocol are retained in the proposed scheme.
Temporal tuning of repetition suppression across the visual cortex
Authors: Fritsche Matthias , Lawrence Samuel J. D. , de Lange Floris P. 
Published: November 2019

The visual system adapts to its recent history. A phenomenon related to this is repetition suppression (RS), a reduction in neural responses to repeated compared with nonrepeated visual input. An intriguing hypothesis is that the timescale over which RS occurs across the visual hierarchy is tuned to the temporal statistics of visual input features, which change rapidly in low-level areas but are more stable in higher level areas. Here, we tested this hypothesis by studying the influence of the temporal lag between successive visual stimuli on RS throughout the visual system using functional (f)MRI. Twelve human volunteers engaged in four fMRI sessions in which we characterized the blood oxygen level-dependent response to pairs of repeated and nonrepeated natural images with interstimulus intervals (ISI) ranging from 50 to 1,000 ms to quantify the temporal tuning of RS along the posterior-anterior axis of the visual system. As expected, RS was maximal for short ISIs and decayed with increasing ISI. Crucially, however, and against our hypothesis, RS decayed at a similar rate in early and late visual areas. This finding challenges the prevailing view that the timescale of RS increases along the posterior-anterior axis of the visual system and suggests that RS is not tuned to temporal input regularities. NEW & NOTEWORTHY Visual areas show reduced neural responses to repeated compared with nonrepeated visual input, a phenomenon termed repetition suppression (RS). Here we show that RS decays at a similar rate in low- and high-level visual areas, suggesting that the short-term decay of RS across the visual hierarchy is not tuned to temporal input regularities. This may limit the specificity with which the mechanisms underlying RS could optimize the processing of input features across the visual hierarchy.
Prevalence of Microembolic Signals in Embolic Stroke of Undetermined Source and Other Subtypes of Ischemic Stroke
Authors: Higuchi Eiko , Toi Sono , Shirai Yuka , Hoshino Takao , Ishizuka Kentaro , Shimizu Satoru , Tsutsumi Yukiko , Kitagawa Kazuo 
Published: November 2019

Background and Purpose—
Embolic stroke of undetermined source (ESUS) has been proposed to cause thromboembolic infarction from unknown but potential embolic sources. However, an embolus remains undetected in ESUS. The goal of this study was to characterize the prevalence and risk factors of microembolic signals (MESs) in ESUS.

Methods—
We examined 108 patients with acute ischemic stroke in the internal carotid artery territory or transient ischemic attack within 14 days of symptom onset and who were admitted to our hospital between April 2017 and March 2019. MESs were monitored in the middle cerebral artery on transcranial Doppler for 60 minutes. We examined the prevalence and number of MES in ESUS and other stroke subtypes, such as cardioembolism, large artery atherosclerosis, cerebral small vessel disease, and transient ischemic attack. The present study was registered in University Hospital Medical Information Network Clinical Trials Registry (UMIN000031913).

Results—
MESs were detected in 33 (31%) of 108 patients. ESUS showed the highest proportion (12/24 [50%]), followed by large artery atherosclerosis (8/20 [40%]), cardioembolism (6/18 [33%]), transient ischemic attack (4/24 [17%]), and cerebral small vessel disease (3/21 [14%]). Univariate analysis showed that higher systolic blood pressure, body mass index, hemoglobin A1c, and ESUS were significantly associated with MES. In multiple logistic regression analysis, ESUS remained significantly associated with MES after adjustment for described covariates from univariate analysis (odds ratio, 2.86 [95% CI, 1.01–8.08]).

Conclusions—
This study demonstrated significant association of ESUS with MES, supporting the embolic nature of this stroke subtype.

Registration—

URL:
https://upload.umin.ac.jp
. Unique identifier: UMIN000031913.
Unraveling the puzzle of Liogenys biodiversity: fifteen new species, nomenclatural acts and new geographical records (Coleoptera: Scarabaeidae)
Authors: Cherman Mariana A. , Basílio Daniel S. , Mise Kleber M. , Almeida Lúcia M. 
Published: November 2019

Liogenys Guérin-Méneville, 1831, the largest genus of Neotropical Diplotaxini, is now comprised of 91 species. Fifteen new Brazilian species are described: L. acuta
sp.n.; L. amazonica
sp.n.; L. angustitarsis
sp.n.; L. clinocarinata
sp.n.; L. crassopunctata
sp.n.; L. hirsuta
sp.n.; L. latoemarginata
sp.n.; L. leviscutata sp.n.; L. ornativentris
sp.n.; L. rodriguesi
sp.n.; L. pruinosa
sp.n.; L. quadrata
sp.n.; L. susanalbertorum
sp.n.; L. variabilis
sp.n.; and L. vazdemelloi
sp.n.. Females are described for the first time for L. acutidens Moser, L. moseri Frey and L. sinuaticeps Moser. For L. macropelma Bates and L. minuta Moser, lectotypes and diagnoses are provided. Two new junior subjective synonyms are made for L. moseri and for L. parva Blanchard: L. obesina Frey and L. femella Cherman, respectively. The geographic distribution of Liogenys is first time recorded in Acre and Rondonia by the occurrence of new species, while other new records are expanded for eight species.
Real World and Tropical Cyclone World. Part II: Sensitivity of Tropical Cyclone Formation to Uniform and Meridionally Varying Sea Surface Temperatures under Aquaplanet Conditions
Authors: Walsh K. J. E. , Sharmila S. , Thatcher M. , Wales S. , Utembe S. , Vaughan A. 
Published: November 2019

AbstractThis study aims to investigate the response of simulated tropical cyclone formation to specific climate conditions, using an idealized aquaplanet framework of an ~40-km-horizontal-resolution atmospheric general circulation model. Two sets of idealized model experiments have been performed, one with a set of uniformly distributed constant global sea surface temperatures (SSTs) and another in which varying meridional SST gradients are imposed. The results show that the strongest relationship between climate and tropical cyclone formation is with vertical static stability: increased static stability is strongly associated with decreased tropical cyclone formation. Vertical wind shear and midtropospheric vertical velocity also appear to be related to tropical cyclone formation, although below a threshold value of wind shear there appears to be little relationship. The relationship of tropical cyclone formation with maximum potential intensity and mean sea surface temperature is weak and not monotonic. These simulations strongly suggest that vertical static stability should be part of any climate theory of tropical cyclone formation.