bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Commercially Available Thread Forming Profiles on Flow Drill Joining of 6061-T6 Aluminum to Thermoset Carbon Fiber Reinforced Composite
Authors: Ruszkiewicz Brandt J. , Simpson Gene , Breidenbaugh Eric 
Published: November 2019

Abstract
Flow Drill Screws are self-piercing, self-tapping screws used for single sided joining of light metals, such as aluminum. This technology has been adopted by many automotive OEMs for use in metals. Thread forming profiles exist for material stackups that are made of entirely metals and entirely polymers/composites. This research evaluated the effectiveness of these thread profiles in dissimilar metal-on-composite stackups. Thread profiles designed for use in polymers/composites and aluminum were compared with a traditional machine screw thread profile for flow drill joining of 1mm and 2mm thick 6061-T6 aluminum to 3mm thick thermoset carbon fiber reinforced polymer. The three thread profiles were manufactured as M5x25mm flow drill screws in their commercially available configurations and materials. Two parameter sets from the FDS equipment manufacturer were evaluated, the first designed for use with the polymer thread forming profile, the second designed for use with the aluminum thread forming profile. The thread profiles were evaluated based on outputs of process time, peak torque, and lap shear strength. The polymer thread profile had shorter process times than the other 2 profiles but caused more damage to itself and its mating material. All 3 thread profiles exhibited greater shear strength when aluminum was used as the lower sheet material.
Fabrication of Deterministic Micro-Asperities on Thrust Surfaces Using Photo Chemical Machining
Authors: Panigrahi Dillip Kumar , Sarangi Mihir 
Published: November 2019

Abstract
The present invention relates to characterization and the sequence of operations in photo chemical machining as a means to fabricate positive deterministic micro-textures on mild steel thrust pad surfaces. Fabrication of surface micro-texture by current technique is conceived in two-stages: where photographic emulsion process is used to pattern the microstructure, and chemical etching method is employed to fabricate the textures on mild steel surface by dissolving exposed metal surface. The texture fabricated by present invention is having slightly rough etched bottom surface with sharp edge and least amount of burrs around the texture rim and the process is also cost effective. Several aspects regarding sequence of operations in manufacturing process and the characterization of fabricated textured surfaces are discussed. The physical significance of micro-asperities on hydrodynamic lubrication is presented experimentally under constant flow system. The variation of hydrodynamic performance parameters such as frictional torque, fluid film thickness and recess pressure with different operating conditions such as varying speed and supply pressure are outlined.
On the Application of Arbitrary Lagrangian-Eulerian and Remeshing Techniques to Simulate Certain Machining and Deformation Processing Operations
Authors: Salilkumar Vandana A. , Sundaram Narayan K. 
Published: November 2019

Abstract
Metal cutting and deformation processing operations provide some of the most challenging problems for modeling and simulation in computational plasticity. These challenges include, but are not limited to, extreme plastic deformation, challenges in constitutive and interfacial friction modeling, microstructural effects, mechanical and thermoplastic instabilities, multiphysics effects due to cutting fluid and high temperatures, and are generally computationally intensive. Despite considerable progress in each of these fronts, there is scope to expand the envelope of simulations that capture the deformation physics while being computationally feasible. Moreover, even conventional standard FEA codes can be leveraged for modeling and simulation in more effective ways. In this work, we present three challenging scenarios for modeling, namely large strain extrusion machining (LSEM), forming using a flat punch, and cutting of inhomogeneous metal, using a mix of Arbitrary Lagrangian Eulerian (ALE), conventional Lagrangian FE, and remeshing techniques. Some of these simulations are ‘standard’, while others are first-in-class, and we discuss both specific and general modeling issues that must be considered to obtain good quality solutions. Specific mechanics insights gleaned from each of these case studies are also presented, ranging from the influence of friction in deep punch indentation to the selection of the chip thickness ratio in LSEM. The last part of this work focuses on problems that arise in the simulation of polycrystalline aggregate cutting, and the progress made in addressing them.
Variable Helix Cutter Design to Suppress Regenerative Effect
Authors: Suzuki Norikazu , Ishiguro Rikiya , Morita Tomoki , Shamoto Eiji 
Published: November 2019

Abstract
Regeneration is a major mechanism to generate self-excited chatter vibration in cutting. Variable helix cutters are useful to suppress regeneration. Although simultaneous optimization of pitch/helix angles is significantly important, there is no practical design methodology to optimize the variable helix cutter geometry so far. In order to attain robust regeneration suppression, a new design method of variable helix cutters is proposed in the present study. The pitch angles vary along axial position due to disagreement of the helix angles. Because of this nature, regeneration can be suppressed in a robust manner with respect to changes of chatter frequency and/or spindle speed. The proposed design satisfies robustness against axial depth of cut variations. Optimal pitch/helix angles are formulated on the basis of distinctive relationship between the cutter geometry and “Regeneration Factor (RF)”, which is an index to quantify influence of regeneration in the process. Through analytical investigations, it is confirmed that regeneration can be suppressed effectively by the proposed method, resulting in significant chatter stability increase. Low immersion milling experiment verified significant stability and robustness of the proposed variable helix design.
Topology Optimization for Multi-Material Lattice Structures With Tailorable Material Properties for Additive Manufacturing
Authors: Venugopal Vysakh , McConaha Matthew , Anand Sam 
Published: November 2019

Abstract
Structurally optimized lattices have gained significant attention since the commercialization of additive manufacturing (AM). These lattices, which can be categorized as metamaterials, are used in aviation and aerospace industries due to their capacity to perform well under extreme structural, thermal, or acoustic loading conditions. This research focuses on the design of a unit cell of a multi-material lattice structure using topology optimization to be manufactured using multi-material additive manufacturing processes. The algorithm combined with octant symmetry and support elimination filters yields optimized unit cells with overall reduction in effective coefficient of thermal expansion and thermal conductivity with high mechanical strength. Such unit cells can be used in multi-material additive manufacturing to generate lattice structures with optimized structural and thermal properties.
Experimental Investigation of Stratasys J750 PolyJet Printer: Effects of Finish Type and Shore Hardness on Surface Roughness
Authors: Wei Xingjian , Bhardwaj Abhinav , Zeng Li , Pei Zhijian 
Published: November 2019

Abstract
The J750 PolyJet printer is the newest model of full-color and multi-material 3D printer from Stratasys. Currently, limited information is available about the effects of control factors on surface roughness of parts printed by this printer. In this study, the effects of two control factors, finish type and Shore hardness, on surface roughness are investigated. The results suggest that both control factors significantly affect surface roughness. Specifically, samples printed with glossy finish have lower surface roughness than those with matte finish, and larger value of Shore hardness leads to lower surface roughness. These results would be valuable to researchers and practitioners who use the J750 3D printer.
Design and Analysis of the Transmission System in Geared Turbofan Engine
Authors: Wang Yanzhong , Yang Kai , Tang Wen 
Published: November 2019

Abstract
A comparative analysis of the structural form and gear type of the gear-driven fan engine reducer is made. Comparative analysis of different transmission structure forms and different gear types, the results show that the star-shaped structure with herringbone gear is more suitable for aero-engine fan reducer, especially in the case of high output speed and high gear bearing capacity. According to the design conditions, the basic parameters of the gear system of the transmission system were preliminarily designed. The gear loading calculations were carried out by finite element method and ISO method respectively, and the root bending stress and tooth surface contact stress obtained by the two methods were compared and analyzed. The results show that the parameters of the fan reducer gear system designed using ISO standards are more conservative. The gear stress obtained by the finite element method simulation is close to the nominal stress calculated in the ISO standard, which verifies the rationality of the finite element model. On this basis, the gear shaping parameters are designed according to the stress and strain conditions of the finite element loading contact analysis, and the appropriate shaping parameters are obtained. Based on the stress and strain results of the finite element loading contact analysis, we designed the gear modification parameters and obtained the appropriate modification parameters.
Quality of care for acute abdominal pain in children
Authors: Zurynski Yvonne , Churruca Kate , Arnolda Gaston , Dalton Sarah , Ting Hsuen P , Hibbert Peter Damian , Molloy Charlotte , Wiles Louise K , de Wet Carl , Braithwaite Jeffrey 
Published: November 2019

ObjectiveTo assess quality of care for children presenting with acute abdominal pain using validated indicators.DesignAudit of care quality for acute abdominal pain according to 21 care quality indicators developed and validated in four stages.Setting and participantsMedical records of children aged 1–15 years receiving care in 2012–2013 were sampled from 57 general practitioners, 34 emergency departments (ED) and 28 hospitals across three Australian states; 6689 medical records were screened for visits for acute abdominal pain and audited by trained paediatric nurses.Outcome measuresAdherence to 21 care quality indicators and three bundles of indicators: bundle A-History; bundle B-Examination; bundle C-Imaging.ResultsFive hundred and fourteen children had 696 visits for acute abdominal pain and adherence was assessed for 9785 individual indicators. The overall adherence was 69.9% (95% CI 64.8% to 74.6%). Adherence to individual indicators ranged from 21.6% for assessment of dehydration to 91.4% for appropriate ordering of imaging. Adherence was low for bundle A-History (29.4%) and bundle B-Examination (10.2%), and high for bundle C-Imaging (91.4%). Adherence to the 21 indicators overall was significantly lower in general practice (62.7%, 95% CI 57.0% to 68.1%) compared with ED (86.0%, 95% CI 83.4% to 88.4%; p<0.0001) and hospital inpatient settings (87.9%, 95% CI 83.1% to 91.8%; p<0.0001).ConclusionsThere was considerable variation in care quality for indicator bundles and care settings. Future work should explore how validated care quality indicator assessments can be embedded into clinical workflows to support continuous care quality improvement.
Static and dynamic charged black holes
Authors: Huang Hyat , Fan Zhong-Ying , Lü H. 
Published: November 2019

AbstractWe consider a class of Einstein–Maxwell–dilaton theories in general dimensions and construct both static and dynamic charged black holes. We adopt the reverse engineering procedure and make a specific ansatz for the scalar field and then derive the necessary scalar potential and the non-minimal coupling function between the scalar and the Maxwell field. The resulting static black holes contain mass and electric charge as integration constants. We find that some of the static solutions can be promoted to become dynamical ones in the Eddington–Finkelstein-like coordinates. The collapse solutions describe the evolution from a smaller charged black hole to a larger black hole state, driven by the scalar field.
WHO ARE THE ADOPTERS OF RETRO-TECHNOLOGY?
Authors: ADAMS JACK , DEDEHAYIR OZGUR , O’CONNOR PETER , NOKELAINEN TOMI 
Published: November 2019

This paper studies the motivations and personality traits of retro-tech adopters. From a survey conducted on Amazon Mechanical Turk with 466 respondents, we conducted an exploratory factor analysis to establish motivational factors, and then ran a correlation analysis to determine the relationships between these motivations and the facet-level traits of the BFI-2 model. Our findings indicate that retro-tech consumers are not a homogenous adopter category, as individuals are affected by different motivations — aesthetic, fashionability, nostalgic positive emotionality, non-conformism and quality. Our study additionally suggests a cyclical conceptualisation of the diffusion of innovations model, or its extension to include a new group of retro-adopters.
Modulatory effects of the supplementary motor area on primary motor cortex outputs
Authors: Côté Sandrine L. , Elgbeili Guillaume , Quessy Stephan , Dancause Numa 
Published: November 2019

Premotor areas of primates are specialized cortical regions that can contribute to hand movements by modulating the outputs of the primary motor cortex (M1). The goal of the present work was to study how the supplementary motor area (SMA) located within the same hemisphere [i.e., ipsilateral SMA (iSMA)] or the opposite hemisphere [i.e., contralateral (cSMA)] modulate the outputs of M1. We used paired-pulse protocols with intracortical stimulations in sedated capuchin monkeys. A conditioning stimulus in iSMA or cSMA was delivered simultaneously or before a test stimulus in M1 with different interstimulus intervals (ISIs) while electromyographic activity was recorded in hand and forearm muscles. The pattern of modulation from iSMA and cSMA shared some clear similarities. In particular, both areas predominantly induced facilitatory effects on M1 outputs with shorter ISIs and inhibitory effects with longer ISIs. However, the incidence and strength of facilitatory effects were greater for iSMA than cSMA. We then compared the pattern of modulatory effects from SMA to the ones from the dorsal and ventral premotor cortexes (PMd and PMv) collected in the same series of experiments. Among premotor areas, the impact of SMA on M1 outputs was always weaker than the one of either PMd or PMv, and this was regardless of the hemisphere, or the ISI, tested. These results show that SMA exerts a unique set of modulations on M1 outputs, which could support its specific function for the production of hand movements. NEW & NOTEWORTHY We unequivocally isolated stimulation to either the ipsilateral or contralateral supplementary motor area (SMA) using invasive techniques and compared their modulatory effects on the outputs of primary motor cortex (M1). Modulations from both SMAs shared many similarities. However, facilitatory effects evoked from ipsilateral SMA were more common and more powerful. This pattern differs from the ones of other premotor areas, which suggests that each premotor area makes unique contributions to the production of motor outputs.
Predictive Model for Mortality Risk Including the Wound, Ischemia, Foot Infection Classification in Patients Undergoing Revascularization for Critical Limb Ischemia
Authors: Azuma Nobuyoshi , Takahara Mitsuyoshi , Kodama Akio , Soga Yoshimitsu , Terashi Hiroto , Tazaki Junichi , Yamaoka Terutoshi , Koya Atsuhiro , Iida Osamu ,   on behalf of the SPINACH Investigators
Published: November 2019

Background:
The aim of this study was to develop a predictive model for mortality risk based on preoperative risk factors, including the Wound, Ischemia, Foot Infection (WIfI) classification, in patients undergoing revascularization for critical limb ischemia.

Methods:
We analyzed a database of the Surgical reconstruction versus Peripheral Intervention in Patients With Critical Limb Ischemia registry, a multicenter, prospective, observational study that included 520 critical limb ischemia patients (192 surgical and 328 endovascular patients).

Results:

Multivariate Cox regression analysis identified old age, impaired mobility, low body mass index, renal failure, heart failure, and high WIfI grade as independent risk factors for all-cause mortality (all
P
<0.05). The risk score comprising these risk factors discriminated the mortality risk well; the 2-year survival rate was >90% in the first quantile of the risk score and ≈20% in the fifth quantile. The area under the time-dependent receiver operating characteristics curve was 0.829 for thirty-day mortality and 0.811 for 2-year mortality. Adding more detailed preoperative information to the predictive model revealed that cystatin C-based estimated glomerular filtration rate, left ventricular ejection fraction, and cholinesterase levels were additional independent risk factors, but the predictive accuracy of the model was not significantly improved, according to the time-dependent receiver operating characteristics curve and net reclassification improvement.

Conclusions:
The current study developed a risk score for mortality using preoperative risk factors, including the WIfI classification, in critical limb ischemia patients undergoing revascularization.
Emergency Medicine Physicians Accurately Select Acute Stroke Patients for Tissue-Type Plasminogen Activator Treatment Using a Checklist
Authors: Berekashvili Ketevan , Zha Alicia M. , Abdel-Al Mohammed , Zhang Xu , Soomro Jazba H. , Prater Samuel J. , Grotta James C. 
Published: November 2019

Background and Purpose—
There is uncertainty among many emergency medicine physicians about the decision to give intravenous tPA (tissue-type plasminogen activator), which limits its use. A checklist approach has been suggested as a solution. We compared agreement on tPA treatment in suspected acute ischemic stroke patients between emergency medicine residents (EMRs) using a checklist and vascular neurology fellows (VNFs).

Methods—
Every suspected acute stroke patient brought to our comprehensive stroke center emergency room within 4.5 hours from symptom onset was prospectively evaluated simultaneously and independently by VNFs and EMRs. The latter used a tPA screening checklist, which included guideline exclusion criteria to help with their treatment decision. Agreement was determined using kappa (k) statistics.

Results—
Over 6 months, 60 patients were enrolled; 10% large vessel atherosclerosis, 18% cardioembolism, 12% small vessel, 12% cryptogenic, and 47% mimic. Forty-two percent were deemed tPA eligible by the EMR, 30% by the VNF, and 37% by the vascular neurology faculty. There were no complications in any tPA-treated patients. Agreement was substantial between EMR and VNF (κ=0.68 [95% CI, 0.49–0.87]) and between EMR and vascular neurology faculty (κ=0.69 [95% CI, 0.50–0.87]). Stroke mimics were the main cause of disagreement between EMR and VNF (κ=0.24 [95% CI, −0.15 to 0.63]) and between EMR and vascular neurology faculty (κ=0.35 [95% CI, −0.08 to 0.78]).

Conclusions—
Our data suggest that with the aid of a checklist, EMRs can accurately treat stroke patients with tPA. Areas for improvement include recognition of stroke mimics. Further studies are warranted to evaluate checklist-enhanced tPA treatment to allay emergency medicine physician uncertainty and expand the use of tPA.
The Ancient Mode of Production, the City-State and Politics
Authors: García Mac Gaw Carlos 
Published: November 2019

AbstractThis paper briefly examines the concept of the ancient mode of production as expressed in Karl Marx’sFormations. It looks at how twentieth-century Marxist historiography picks up this concept in its characterisation of the Greco-Roman city-state. It explores the feasibility of the use of the concept in relation to the advancement of knowledge of the city-state, especially through the development of archaeology. It examines how social classes are structured and relations of exploitation are presented. And it analyses the need for politics in the organisation of this socio-economic form in terms of how it is joined up with the social relations of production.
Experience with Minimally Invasive Ponto Surgery and Linear Incision Approach for Pediatric and Adult Bone Anchored Hearing Implants
Authors: Bezdjian Aren , Smith Rachel Ann , Gabra Nathalie , Yang Luhe , Bianchi Marco , Daniel Sam J. 
Published: November 2019

Purpose: To compare intra- and postoperative outcomes between the standard linear incision with tissue preservation and the Minimally Invasive Ponto Surgery (MIPS). Study Design: A non-randomized retrospective cohort series. Methods: Medical files were reviewed of adult and pediatric bone anchored hearing implant recipients. Extracted outcomes included patient characteristics, implant survival, operative time, anesthesia use, intra and postoperative complications, soft tissue tolerability assessed by the Holger’s classification, and implant stability assessed by the Resonance Frequency Analysis (RFA). Outcomes were compared between two surgeries. Results: A total of 59 implants were placed (21 MIPS; 38 linear). Conductive hearing loss was the most common etiology for implantation. Surgery was conducted under local anesthesia in 67% of MIPS patients and 16% of linear patients. No intraoperative complications were reported for both surgical approaches and no implants were lost. Patients undergoing implantation via the MIPS approach displayed less skin reaction postoperatively, however this was not significant ( P = .2848). The most common Holgers score for both groups was grade 1. The median and mean surgical duration for the MIPS group was statistically lower than the linear group ( P = .0001). Implant stability measured by the RFA implant stability quotient was greater in the MIPS cohort. Conclusion: The MIPS approach seems either similar or superior to the linear approach in all perioperative outcomes evaluated. Outcomes such as surgical duration, anesthesia choice and implant stability measurements support implantation through the MIPS approach for patients meeting eligibility criteria.
Sri Lanka–China Economic Relations in Comparative Perspective: Ample Room to Grow
Authors: Deyshappriya N. P. Ravindra 
Published: November 2019

The article examines recent trends in the economic relations between Sri Lanka and China focussing on trade, investment and tourism dimensions. Although bilateral economic ties between Sri Lanka and China have strengthened over time, the article demonstrates Sri Lanka’s low rank among China’s economic partners. For example, while China is the second-largest tourism partner of Sri Lanka in terms of tourist arrivals, Sri Lanka does not rank among even China’s top 25 tourist destinations. Consequently, the article recommends certain policy priorities to ensure mutually beneficial economic relations. With regards to tourism, it recommends promoting Sri Lanka’s brand on Chinese e-tourism websites and social media, introducing user-friendly tourist apps in Chinese, strengthening air connectivity and celebrating Chinese festivals. Similarly, trade and investment could be facilitated by stronger links with Chinese cities and connecting Sri Lankan students in China to the Chinese industry via internships and building commercial networks from the ground up.