bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Belt Flexural Rigidity on the Transmission Error of a Carriage-Driving System
Authors: Tai Hung-Ming , Sung Cheng-Kuo 
Published: December 2020

Abstract
This paper investigates the effects of belt flexural rigidity and belt tension on transmission error of a carriage-driving system. The beam model associated with both the clamped and moving boundary conditions at two ends is utilized to derive the governing equation of the belt. The belt flexural rigidity is obtained and verified by an experimental technique. In addition, a numerical method is proposed to determine the belt profile, transmission error and transmission stiffness. Results show that transmission error of a carriage-driving system increases when the carriage moves away from the driving pulley due to finite belt flexural rigidity. According to the analyses, application of appropriate tension on the belt can significantly reduce the error. Furthermore, the transmission stiffness for representing the entire rigidity between the carriage and pulley is investigated based on the proposed beam model. A three-dimensional plot that indicates the relationship among the transmission stiffness, belt tension and the position of the carriage is obtained.
Kinematics of the Full-Toroidal Traction Drive Variator
Authors: Raghavan Madhusudan 
Published: December 2020

Abstract
We present a geometric derivation of the kinematics of the steering action and the roller displacement in a full-toroidal continuously variable traction drive variator. In particular, expressions relating the inclination of the roller to its displacement for designs incorporating a caster angle are derived. These results are useful in the design of the control system for the variator.
Optimization-Based Synthesis of Grashof Geared Five-Bar Mechanisms
Authors: Nokleby Scott B. , Podhorodeski Ron P. 
Published: December 2020

Abstract
A quasi-Newton optimization routine and Grashof criteria for geared five-bar mechanisms are used to develop a Grashof five-bar mechanism synthesis routine. The synthesis routine uses a sequential transformation set that maps from an unconstrained search variable space to a constrained design variable space. The transformation set ensures that Grashof criteria are satisfied and that all mechanism parameters satisfy specified upper and lower constraints. Example results demonstrate the effectiveness of the quasi-Newton optimization technique, along with appropriate parameter transformations and geared five-bar Grashof criteria, for the synthesis of Grashof five-bar mechanisms.
Double Points and Unstable Configurations of Stephenson-I, -II, and -III Mechanisms
Authors: Kohli D. , Pan C. A. , Dhingra A. K. 
Published: December 2020

Abstract
Double points are conjugate configurations in mechanisms, with multiple closed-loops, when both input and output links are fixed in the same position and some passive joints can be located in two different configurations. Unstable configurations, on other hand, are positions where a mechanism loses controllability and gains at least one unwanted DOF instantaneously. The analytical condition for the occurrence of double point is the same as the occurrence of an unstable configuration, i.e., two roots of input-output displacement polynomial are equal. This paper addresses the determination of double points and unstable configurations of six-link Stephenson-I, -II and -III mechanisms. The double points are determined by using the loop-closure equations for two branches and successively eliminating intermediate joint variables using closed-form techniques. Further, extraneous roots from algebraic manipulations are eliminated using a new technique of two-branch equation substitution. The unstable configuration polynomial is derived by (i) successively eliminating intermediate variables from loop-closure equations to obtain the input-output displacement polynomial, (ii) equating the polynomial discriminant to zero to obtain a polynomial which contains both unstable configurations and double points, and (iii) eliminating extraneous roots from algebraic manipulations and double points from this composite polynomial to determine the unstable configurations. The computational procedure is illustrated through numerical examples.
Comparison of Damped Velocity and Acceleration Control for Non-Redundant Manipulators
Authors: Chen Yu-Che , O’Neil Kevin A. 
Published: December 2020

Abstract
Damped Least Square (DLS) method has been widely used as an on-line algorithm for manipulator path tracking near and at singular configurations. Wampler (1986) formulated the framework of DLS method applied to velocity control and addressed the applicability of DLS method to acceleration control. The purpose of this paper is to demonstrate the differences in the joint paths generated by damped velocity and damped acceleration control algorithms in non-redundant manipulators. We examine these joint paths, find the cause of the differences, and demonstrate the features of damped acceleration control in non-redundant manipulator dynamics. Simulation results on a planar 2R and a spatial 6R manipulator moving through and near singular configurations verify the phenomena analyzed.
Singularities Analysis of Basic Kinematic Chains and Complex Multiloop Planar Linkages
Authors: Shen Hui-ping , Ting Kwun-Lon , Yang Ting-Ii 
Published: December 2020

Abstract
This paper offers a general approach for the singularity analysis of arbitrary complex multiloop planar linkages. A complex linkage is regarded as one composed of the input links and one or more zero degree-of-freedom basic kinematic chains. A complex linkages under a different input condition may decompose some different types of basic kinematic chains, and different linkages may correspond to the same basic kinematic chains. A general treatment for the singularity analysis of complex multiloop planar linkages is presented, i.e, firstly, decompose a complex linkage into basic kinematic chains (BKCs), then, based on the velocity matrix, deduce the analytical singularity conditions for these BKCs, and last, obtain the singular positions of linkages by the numerical solution method, or by the corresponding singular geometric configurations derived from singularity equations, i.e. the graphic solution method. These basic kinematic chains then served as the modules or building blocks of singularity analysis for complex linkages and manipulators. Meanwhile, three important conclusions for singularity analysis have been drawn: (1)The analytical singularity conditions for a BKC are not related with its assembly configurations; (2) The singular positions for a linkages depend on the type of BKC s and the parameters of the links; (3). When only one basic kinematic chain reaches a singular configuration, the complex linkage is at a singular position. Thus, the method of singularity analysis for a limited number of basic kinematic chains can be expanded to all complex planar linkages and parallel manipulators, and the singularity analysis of a complex linkage can simplified to singularity analysis of their BKCs. This paper also offers and discusses a formula to estimate the maximum of singular positions of a complex multiloop linkage. The approach is demonstrated in a Stephenson complex linkages with six-bar and two-loop.
Building Around Inserts: Methods for Fabricating Complex Devices in Stereolithography
Authors: Kataria Alok , Rosen David W. 
Published: December 2020

Abstract
One of the most common Rapid Prototyping (RP) technologies, the stereolithography apparatus (SLA) fabricates 3-dimensional parts using a layer-based, additive fabrication process by tracing part cross-sections on the top surface of a vat of liquid photopolymer. Typically, usage of the SLA process has been limited to piece parts. We are interested in greatly expanding the application of SLA and other RP technologies by fabricating assemblies of parts as working mechanisms or static, complex structures which we call “live” or “smart” models. To accomplish this, we are investigating methods for building around embedded components, where these components are motors, printed circuit boards, metal bushings, etc. In this paper, we present example prototypes to illustrate the power of building around inserts (embedded components). We report on our problem formulation and a solution approach in the form of a procedure for building around inserts. We believe that our procedure and results lend insight into promising new applications of SLA technology, as well as novel methods of implementing additional functionality into SLA and other RP technologies.
Approximation of Rational Cartesian Trajectories Using Low-Harmonic Robot Joint Trajectories
Authors: Cheng Guolin , Ge Q. J. 
Published: December 2020

Abstract
This paper deals with the problem of trajectory synthesis for computer controlled machinery such as robot manipulators. Low-harmonic Bezier and B-spline joint trajectory are used to approximate rational Bezier and B-spline Cartesian trajectories with desired kinematic characteristics. Two examples are given for the case of PUMA 560 robotic arm for synthesizing two- and three-harmonic joint trajectories that approximate a rational B-spline Cartesian motion of degree 6.
Laurentide ice sheet thinning and erosive regimes at Mount Washington, New Hampshire, inferred from multiple cosmogenic nuclides
Authors: Koester Alexandria J. , Shakun Jeremy D. , Bierman Paul R. , Davis P. Thompson , Corbett Lee B. , Goehring Brent M. , Vickers Anthony C. , Zimmerman Susan R. 
Published: December 2020

ABSTRACT
The northward retreat history of the Laurentide ice sheet through the lowlands of the northeastern United States during the last deglaciation is well constrained, but its vertical thinning history is less well known because of the lack of direct constraints on ice thickness through time and space. In addition, the highest elevations in New England are characterized by gently sloping upland surfaces and weathered block fields, features with an uncertain history. To better constrain ice-sheet history in this area and its relationship to alpine geomorphology, we present 20 new 10Be and seven in situ 14C cosmogenic nuclide measurements along an elevation transect at Mount Washington, New Hampshire, the highest mountain in the northeastern United States (1917 m above sea level [a.s.l.]). Our results suggest substantially different exposure and erosion histories on the upper and lower parts of the mountain. Above 1600 m a.s.l., 10Be and in situ 14C measurements are consistent with upper reaches of the mountain deglaciating by 18 ka. However, some 10Be ages are up to several times greater than the age of the last deglaciation, consistent with weakly erosive, cold-based ice that did not deeply erode preglacial surfaces. Below 1600 m a.s.l., 10Be ages are indistinguishable over a nearly 900 m range in elevation and imply rapid ice-surface lowering ca. 14.1 ± 1.1 ka (1 standard deviation; n = 9). This shift from slow thinning early in the deglaciation on the upper part of the mountain to abrupt thinning across the lower elevations coincided with accelerated ice-margin retreat through the region recorded by Connecticut River valley varve records during the Bølling interstadial. The Mount Washington cosmogenic nuclide vertical transect and the Connecticut River valley varve record, along with other New England cosmogenic nuclide records, suggest rapid ice-volume loss in the interior northeastern United States in response to Bølling warming.
Mapping metamorphic hydration fronts with field-based near-infrared spectroscopy: Teakettle Junction contact aureole, Death Valley National Park (California, USA)
Authors: Duke Edward F. 
Published: December 2020

Abstract
Mineral distribution in a previously undescribed contact aureole in siliceous dolomite at Teakettle Junction, Death Valley National Park (California, USA), was mapped with a handheld visible and near-infrared (Vis-NIR, 0.35–2.5 μm) spectrometer. With increasing distance from a small Jurassic(?) pluton, the following mineral zones occur: periclase (hydrated to brucite), forsterite (variably hydrated to serpentine and typically accompanied by clinohumite), tremolite, and talc. Airborne Vis-NIR imaging spectrometer data with 5 m ground resolution shows serpentine and tremolite distribution in close agreement with the field data. Field measurements show dolomite and calcite throughout the study area, along with minor amounts of phlogopite and illite. Hydrous minerals were detected in field measurements at levels on the order of 1 vol%. Phlogopite, talc, and illite crystals in many samples are &lt;20 μm in size and difficult to identify without scanning electron microscopy examination. Sensitivity of Vis-NIR spectroscopy to hydrous minerals is especially important in the context of metamorphic fluid flow. Significant hydration of wall rocks is limited to samples between the pluton contact and the serpentine (forsterite) isograd as shown by mineral distribution and variation in the depth of the OH absorption feature near 1.4 μm. This boundary is interpreted to represent a metamorphic hydration front beyond which there was minimal infiltration of wall rocks by H2O-rich fluid. Within this zone of hydration, however, the extent of hydration is highly variable, even at individual sample sites with samples spaced on the order of 1 m or less. Heterogeneity of fluid-rock interaction at this scale must be considered in models of heat and mass transfer accompanying contact metamorphism.
Creating virtual geologic mapping exercises in a changing world
Authors: Whitmeyer S.J. , Dordevic M. 
Published: December 2020

AbstractFieldwork has long been considered an essential component of geoscience research and education, with student field experiences consistently valued for their effectiveness in developing expertise in geoscience skills and cognitive abilities. However, some geoscience disciplines recently have exhibited a decreasing focus on data collection in the field. Additionally, some students have been disinclined to pursue a geoscience career if physical fieldwork is perceived as necessary for the completion of their academic degree. More recently, travel restrictions due to the COVID-19 pandemic have restricted access to field locations for many students and geoscience researchers. As a result, geoscience educators are developing virtual field trips and exercises that address many of the learning objectives of traditional in-person field experiences. These virtual field trips and exercises use a variety of online and computer platforms, including web-based and desktop versions of Google Earth (GE). In this contribution, we highlight how educators can create virtual geoscience field trips and exercises using web GE, desktop GE, and a web-based tool for generating oriented geologic symbology for GE. Examples of methods and approaches for creating virtual field experiences in GE are provided for a virtual field trip that uses a web GE presentation to replicate a typical class field trip, and for a geologic mapping exercise that uses a KML file uploaded into web or desktop GE. Important differences between web and desktop GE are discussed, with consideration for which platform might be most effective for specific educational objectives. Challenges and opportunities related to virtual field trips are discussed in comparison with traditional in-person, on-location field trips. It is suggested that in a post–COVID-19 world, a combination of in-person and virtual hybrid field experiences might prove the most effective approach for producing a more inclusive and equitable learning environment, and thus strengthening the geoscience workforce.
Associations between alcohol consumption trajectory and deaths due to cancer, cardiovascular diseases and all-cause mortality: a 30-year follow-up cohort study in Thailand
Authors: Jankhotkaew Jintana , Bundhamcharoen Kanitta , Suphanchaimat Rapeepong , Waleewong Orratai , Chaiyasong Surasak , Markchang Kamolphat , Wongworachate Chadthapong , Vathesatogkit Prin , Sritara Piyamitr 
Published: December 2020

ObjectivesThis study examined the association between alcohol consumption trajectory and deaths due to cancer, cardiovascular diseases (CVDs) and all-cause mortality in Thailand.DesignData were obtained from a Thai prospective cohort study with more than 30 years of follow-up (n=1961).SettingAll participants resided in Bangkok and its vicinity.ParticipantsEmployees from the Electricity Generating Authority of Thailand aged between 35 and 54 years old were randomly selected.Main outcome measuresExposure was alcohol consumption trajectory over the study period from 1985 to 2012. The main outcomes were all-cause mortality, and deaths due to cancer and CVDs recorded in national vital registries between 2002 and 2015. Cox’s proportional hazard regression was used to determine the associations between alcohol consumption trajectory and each outcome adjusting for sample characteristics, health behaviours and health conditions.ResultsFrom a total of 59 312 person years, 276 deaths were observed. Compared with drinkers who drank occasionally or most occasional over their lifetime, consistent regular or mostly consistent-regular drinkers had higher rates of all-cause mortality (HR: 1.53; 95% CI 1.09 to 2.16) and cancer mortality (HR: 2.05; 95% CI 1.13 to 3.74). The study did not find a significant association between trajectory of alcohol consumption and deaths due to CVDs.ConclusionsRegular drinking of alcohol increased risk for all-cause and cancer mortality. Effective interventions should be implemented to reduce number of regular drinkers in order to saves life of individuals.
Spatial inequalities of major lower limb amputation rates in Paraná state, Brazil
Authors: Franco Rogério do Lago , Iora Pedro Henrique , Dutra Amanda Carvalho , Belczak Sérgio Quilici , Vissoci João , Staton Catherine , Andrade Luciano 
Published: December 2020

ObjectiveThe aim of this observational cross-sectional study was to analyse the spatial distribution of major lower limb amputation (MLLA) rates and associate them to socioeconomic, demographic and public healthcare access-related variables in the State of Paraná, Brazil, from 2012 to 2017.MethodData on MLLA, revascularisation surgeries, diagnostic exams and healthcare coverage were obtained from the Brazilian Public Hospital Information System. Socioeconomic data were obtained from the Brazilian Institute of Geography and Statistics. Spatial autocorrelation of the MLLA rates was tested using Moran’s I method. Multivariate spatial regression models using ordinary least squares regression (OLS) and geographically weighted regression (GWR) were used to identify the variables significantly correlated with MLLA.ResultsA total of 5270 MLLA were included in the analysis. Mean MLLA rates were 24.32 (±18.22)/100 000 inhabitants, showing a positive global spatial autocorrelation (Moran’s I=0.66; p<0.001). Queen contiguity matrix demonstrates that MLLA rates ranged from 7.6 to 46.6/100 000 with five large clusters of high MLLA rates. OLS showed that four of the nine studied variables presented significant spatial correlation with MLLA rates. Colour Doppler ultrasound showed a negative association (p<0.001), while revascularisation surgeries and illiteracy showed a positive correlation (p<0.01). GWR presented the best model (adjusted R2=0.77) showing that the predictors differentially affect the MLLA rates geographically.ConclusionThe high MLLA rates in some regions of the state are influenced by the high rate of illiteracy and low utilisation rate of colour Doppler, indicating a social problem and difficulty in accessing health. On the other hand, the high rates of revascularisation surgeries are related to higher MLLA rates, possibly due to delayed access to specialised hospitals. This indicates that attention must be given to population access to public healthcare in the State of Paraná in order to ensure proper and timely medical attention.
Clinical, laboratory and imaging predictors for critical illness and mortality in patients with COVID-19: protocol for a systematic review and meta-analysis
Authors: Lai Xinxing , Liu Jian , Zhang Tianyi , Feng Luda , Jiang Ping , Kang Ligaoge , Liu Qiang , Gao Ying 
Published: December 2020

IntroductionWith the threat of a worldwide pandemic of COVID-19, it is important to identify the prognostic factors for critical conditions among patients with non-critical COVID-19. Prognostic factors and models may assist front-line clinicians in rapid identification of high-risk patients, early management of modifiable factors, appropriate triaging and optimising the use of limited healthcare resources. We aim to systematically assess the clinical, laboratory and imaging predictors as well as prediction models for severe or critical illness and mortality in patients with COVID-19.Methods and analysisAll peer-reviewed and preprint primary articles with a longitudinal design that focused on prognostic factors or models for critical illness and mortality related to COVID-19 will be eligible for inclusion. A systematic search of 11 databases including PubMed, EMBASE, Web of Science, Cochrane Library, CNKI, VIP, Wanfang Data, SinoMed, bioRxiv, Arxiv and MedRxiv will be conducted. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction will be performed using the modified version of the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist and quality will be evaluated using the Newcastle-Ottawa Scale and the Quality In Prognosis Studies tool. The association between prognostic factors and outcomes of interest will be synthesised and a meta-analysis will be conducted with three or more studies reporting a particular factor in a consistent manner.Ethics and disseminationEthical approval was not required for this systematic review. We will disseminate our findings through publication in a peer-reviewed journal.PROSPERO registration numberCRD 42020178798.
Effects of dry cupping on pain, function and quality of life in women with knee osteoarthritis: a protocol for a sham-controlled randomised trial
Authors: Pontes Nayara Silva , Barbosa Germanna Medeiros , Almeida Silva Hugo Jário , Scattone Silva Rodrigo , Souza Clécio Gabriel , Lins Caio Alano de Almeida , de Souza Marcelo Cardoso 
Published: December 2020

IntroductionKnee osteoarthritis (KOA) is the most common cause of pain and disability worldwide. Dry cupping has been used as non-pharmacological approach to control pain and improve physical function. However, there is a lack of high-quality scientific evidence regarding its effects on this condition. This protocol describes a sham-controlled, randomised and simple blind study that aims to evaluate the effect of dry cupping on pain, function and quality of life in women with KOA.Methods and analysisSixty-two women diagnosed with KOA, based on American College of Rheumatology clinical criteria, and aged from 50 to 75 years, will be randomly distributed into two groups (31 per group): real and sham dry cupping. Both applications will occur with acrylic cups around the knee. The intervention will last 15 min, two times a week over six consecutive weeks, for a total of 12 sessions. Both groups will be assessed at four different times: before the intervention (T0), after 3 weeks intervention (T3), at the end of the protocol (T6) and 4 weeks after the interventions (follow-up: T10). The primary outcome will be pain intensity (Numerical Pain Rating Scale), and secondary outcomes will be knee-related health status (Western Ontario and McMaster Universities Osteoarthritis Index), functional capacity (8-step stair climb test, 40-metre fast-paced walk test and 30-second chair stand test), quality of life (Short-Form 36) and global perceived effect.Ethics and disseminationThis protocol was approved by the UFRN/FACISA Ethics Committee (number 3.737.688). The study results will be disseminated to the participants and submitted to a peer-reviewed journal and scientific meetings.Trial registration numberNCT04331158.