bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Angle of Pressure in the Chain-Wave Transmission and the Optimum Number of Teeth of its Sprockets
Authors: Amiryan Ara K. 
Published: February 2021

Abstract
This paper is about the chain-wave transmission (CWT), that is a new kind of harmonic drives. The objective of this work is the determination of the angle of pressure in chain-wave mechanisms and the investigation to find the constraint between the angle of pressure and geometrical parameters of the CWT. In the first part are described also objectives for the creation of the chain-wave transmission and main advantages of its construction. It is determined the angle of pressure on the basis of dynamic syntheses of the chain-wave mechanism. The compression factor of the form of the wave generator is taken as a geometric parameter, which is influence upon the angle of pressure. It is determined also that the compression factor depends on number of teeth of the interacting sprocket and on factor of multiplicity of the CWT and it is necessary to limit their values at designing of chain-wave mechanisms.
Four-Link Anti-Squat and Drag Racing Motorcycle Performance: A Parametric Study
Authors: Wiers Paul C. , Dhingra A. K. 
Published: February 2021

Abstract
Anti-squat is a transient vehicle suspension parameter which can dramatically affect tractive effort available at motorcycle drive tire. In the drag racing environment, maximizing tractive effort is essential to competitive performance. Tuning a four-link rear suspension to provide anti-squat increases rear tire traction at the starting line, which increases tractive effort and vehicle acceleration performance. Minimization of the time required to initiate and maintain forward acceleration, often considered the most important part of a drag race, enables peak overall race performance to be realized. Utilizing PC based CAD, finite element analysis, and dynamic system analysis software, a motorcycle rear suspension system was designed, built and tested under actual racing conditions. Parametric studies using dynamic theoretical models were conducted for both unsuspended and four-link equipped versions of the same vehicle. Results and conclusions are presented. Based on the results, it is shown the four-link suspension, when applied to a drag racing motorcycle, does provide opportunity for improving tractive effort at the beginning of a race which will improve overall drag racing performance.
The Design Implications of Chaotic and Near-Chaotic Vibrations in Machines
Authors: Gu Pengyun , Dubowsky Steven , Mavroidis Constantinos 
Published: February 2021

Abstract
Accurate performance prediction is key to the design of high performance machines. It is shown here that connection clearance and component flexibility can result in machine dynamic behaviors that are hypersensitive to small variations of system design parameters and operating conditions. These hypersensitivities, which can limit the usefulness of computer dynamic simulations for design, are associated with chaotic and near chaotic behavior. The dynamic behaviors of two systems, an Impact Beam System and a Spatial Slider Crank, are studied. The chaotic vibration of these systems is confirmed numerically and experimentally. Hypersensitivity is shown for both chaotic and periodic response regions, in which case actual dynamic behavior of such machines could be very different in practice from that predicated by design simulation studies. Design guidelines are developed for evaluating the fatigue life and the reliability of machines under these conditions.
Contact Force Analysis in an OHC Finger-Follower-Type Cam-Valve System With Different Dynamic Models
Authors: Liu Xiaoming , Ling Zhi-Kui 
Published: February 2021

Abstract
This study uses various dynamic models to predict contact forces in a finger-follower-type cam-valve system. It is found that the following factors have the greatest impact on the overall behavior of a cam valve system. They are the cam profile, valve spring, and rocker arm ratio. In this study, different techniques in modeling cam profiles are explored. Various ways of modeling valve-springs are examined. The rocker-arm ratio is assumed to be either a nonlinear function or a constant. Since the speed of the cam dictates a great deal in the overall behavior of the system, three different cam speeds are tested in this study. The models used in this study are established with a constructive approach by using a commercially available software system.
A Simple and Accurate Method for Determining Large Deflections in Complaint Mechanisms Subjected to End Forces and Moments
Authors: Saxena A. , Kramer Steven N. 
Published: February 2021

Abstract
Compliant members in flexible link mechanisms undergo large deflections when subjected to external loads for which, traditional methods of deflection analysis do not apply Nonlinearities introduced by these large deflections make the system comprising such members difficult to solve Parametric deflection approximations are then deemed helpful in the analysis and synthesis of compliant mechanisms This is accomplished by seeking the pseudo-rigid-body model representation of the compliant mechanism A wealth of analysis and synthesis techniques available for rigid-body mechanisms thus become amenable to the design of compliant mechanisms In this paper, a pseudo-rigid-body model is developed and solved for the tip deflection of flexible beams for combined end loads with positive end moments A numerical integration technique using quadrature formulae has been employed to solve the nonlinear Bernoulli-Euler beam equation for the tip deflection Implementation of this scheme is relatively simpler than the elliptic integral formulation and provides nearly accurate results Results of the numerical integration scheme are compared with the beam finite element analysis An example for the synthesis of a compliant mechanism using the proposed model is also presented.
SPADES: Software for Synthesizing Spatial 4C Mechanisms
Authors: Larochelle Pierre M. 
Published: February 2021

Abstract
In this paper we present Spades, an interactive graphics based software package for SPAtial mechanism DESign. The program provides a platform for the synthesis of a mechanism that guides a body through either three or four prescribed positions in space.
The purpose of this work is to assemble the current spatial 4C synthesis theory into a software package that is useful for spatial mechanism design and research.
Completely Specified Displacements of a Rigid Body and Their Application in the Direct Kinematics of In-Parallel Mechanisms
Authors: Mavroidis Constantinos 
Published: February 2021

Abstract
In this paper we study the type of completely specified displacements of a rigid body where the distances of six points on the body, between their final and initial positions, have been specified. A method is presented to calculate the screws associated with these displacements. It is shown that there are 24 different screws at the most that will bring the rigid body from the initial to its final position to satisfy the six distances. If the six points are co-planar or symmetrical with respect to a plane then the number of screws reduces to 16. The method to calculate the screws associated with these completely specified displacements, is used to obtain a simple algebraic solution to the direct kinematics problem of a special type of in-parallel mechanisms: the mechanisms where the moving and the fixed platforms are the same.
Mobility in Metamorphic Mechanisms of Foldable/Erectable Kinds
Authors: Dai Jian S. , Jones John Rees 
Published: February 2021

Abstract
This paper looks at class of mechanisms that change structure when erected or folded. The class includes a variety of artefacts and decorative gifts and boxes comprised of flat card creased to enable the folding or unfolding of a structure. Such a structure admits kinematics study in keeping with theory of mechanisms when the creases are treated as hinges joining card and paper panels treated as links. New horizons have been brought up in the use and mechanised manufacture of mechanisms of this kind. Here typical types are described in terms of their fundamental parts and their equivalent mechanisms. Screw system theory is brought into the analysis of mechanisms of these kinds, particularly those containing multiple loops. Different geometry and system combinations are used for the study of mobility and kinematics making use of the result from the equivalent screw systems.
Catastrophe Analysis of Planar Three-Spring Systems
Authors: Yin J. P. , Marsh D. , Duffy J. 
Published: February 2021

Abstract
A special planar three-spring mechanism is proposed for contact force control. An energy function is defined to describe the behavior of this kind of mechanism. It can be used to perform the catastrophe analysis of this mechanism. The analysis result can be used as a design and control tool. By comparing the three-spring system and a two-spring system, we found the three-spring mechanism has better stability than the two-spring system. A three-spring mechanism which can be used to control a general contact force in a plane is also analyzed.
Study on Dimension Synthesis of Planar 4-Bar Linkages for Rigid-Body Guidance With Prescribed Timing
Authors: Xin Wu , Jinkui Chu , Weiqing Cao 
Published: February 2021

Abstract
A computer method is firstly proposed, which is used to do the dimension synthesis of planar 4-bar linkages for rigid-body guidance with Prescribed Timing (in short PT) by harmonic component’s database of the coupler’s rotation-angle function. The relationship between position function of rigid-body guidance with PT and coupler’s rotation-angle function of 4-bar linkage is analyzed. The key of the method is to solve the real dimension of linkage, coupler’s point position and installing dimensions of the linkage. Considering solving the problem, a harmonic component’s database of the coupler’s rotation-angle function including 20350 dimensional types, taking the crank-rocker linkage as an example, is established. So, it is possible to choose some linkages from the database to realize rigid-body guidance with PT by using fuzzy identification method quickly, and to approximately achieve “infinite positions” of dimensional synthesis for rigid-body guidance. An example is given to illustrate the efficiency and advantage of this method.
An Iterative Kinematic and Force Solution Method for Revolute Joints With Clearances
Authors: Biswas Arunava , Kinzel Gary L. 
Published: February 2021

Abstract
This paper outlines a procedure for modeling revolute joints with clearances and solving for the quasi-static forces in a mechanism with clearances in the joints. The results from the force analysis are used in an iterative fashion along with the position, velocity, and acceleration analysis to finally obtain the kinematic solution for the mechanism with clearances at the joints. The iterative procedure is general and essentially remains the same for other joint types. The situation for revolute joints is presented here. A general outline of the clearance joint model and the iterative procedure is given first, followed by the flowchart of the process and an example.
Singularity and Controllability Analysis of Parallel Manipulators
Authors: Choudhury Prasun , Ghosal Ashitava 
Published: February 2021

Abstract
This paper presents a study of kinematic and force singularities and their relationship to the controllability of planar and spatial parallel manipulators. Parallel manipulators are classified according to their degrees of freedom, number of output Cartesian variables used to describe their motion and the number of actuated joint inputs. The singularities in the workspace of a parallel manipulator are studied by considering the force transformation matrix which maps the forces and torques in joint space to output forces and torques in Cartesian space. The uncontrollable regions in the workspace of the parallel manipulator are obtained by deriving the equations of motion in terms of Cartesian variables and by using techniques from Lie Algebra. We show that when the number of actuated joint inputs is equal to the number of output Cartesian variables, and the force transformation matrix loses rank, the parallel manipulator is uncontrollable. For the case of manipulators where the number of joint inputs is less than the number of output Cartesian variables, if the constraint forces and torques (represented by the Lagrange multipliers) become infinite, the force transformation matrix loses rank. Finally, we show that the singular and uncontrollable regions in the workspace of a parallel manipulator can be reduced by adding redundant joint actuators and links. The results are illustrated with the help of numerical examples where we plot the singular and uncontrollable regions of parallel manipulators belonging to the above mentioned classes.
Kinetostatic Synthesis of Coupled Serial Chains
Authors: Krovi Venkat , Ananthasuresh G. K. , Kumar Vijay 
Published: February 2021

Abstract
Single Degree-of-freedom Coupled Serial Chain (SDCSC) mechanisms are a novel class of modular and compact mechanisms with single degree-of-freedom actuation and control. In this paper, the kinetostatic synthesis of SDCSC mechanisms is addressed. Using the principle of virtual work, the static force equilibrium equations are developed for two-link SDCSCs. These are combined with the previously developed kinematic loop-closure equations to solve the kinetostatic precision point synthesis problem. Since the ratios of the angular velocities at the joints are constants by virtue of cable-pulley coupling in SDCSCs, it possible to render the kinetostatic equations linear in terms of the mechanism parameters. As a result, the solution of the precision point synthesis problem of SDCSCs becomes simpler compared to that of the four-bar mechanism. In order to meet additional criteria such as minimizing the maximum torque required over the entire range of motion of the mechanism, an optimization problem is formulated. The free choices in the precision point synthesis are used as variables in the optimal synthesis problem. The paper also addresses how torsional springs at the joints can be utilized to reduce the required input torque in supporting a specified load at the end-effector. Numerical examples are presented to illustrate the precision point and the optimal synthesis of two-link SDCSC mechanism with and without torsional springs at the joints.
Combined Trajectory Planning and Parameter Identification of a Two-Link Rigid Manipulator
Authors: Fotouhi-C. Reza , Nikiforuk Peter N. , Szyszkowski Walerian 
Published: February 2021

Abstract
A combined trajectory planning problem and adaptive control problem for a two-link rigid manipulator is presented in this paper. The problem is divided into two parts: path planning for off-line processing, followed by on-line path tracking using an adaptive controller. The path planning is done at the joint level. The motion of the robot is specified by a sequence of knots (positions of the robot’s tip) in space Cartesian coordinates. These knots are then transformed into two sets of joint displacements, and piecewise cubic polynomials are used to fit these two sequences of joint displacements. The cubic spline function is used to construct a trajectory with the velocity and the acceleration as constraints. Linear scaling of the time variable is used to accommodate the velocity and acceleration constraints. A nonlinear scaling of the time variable is performed to fit the velocity to a pre-specified velocity profile. The adaptive scheme used takes full advantage of the known parameters of the manipulator while estimating the unknown parameters. In deriving the dynamic equations of motion, all of the physical parameters of the manipulator, including the distributed masses of the links, are taken into account. Some simulation results for the manipulator with unknown payload masses following a planned trajectory are presented.
Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships
Authors: Racinais Sebastien , Ihsan Mohammed , Taylor Lee , Cardinale Marco , Adami Paolo Emilio , Alonso Juan Manuel , Bouscaren Nicolas , Buitrago Sebastian , Esh Chris J , Gomez-Ezeiza Josu , Garrandes Frederic , Havenith George , Labidi Mariem , Lange Gunter , Lloyd Alexander , Moussay Sebastien , Mtibaa Khouloud , Townsend Nathan , Wilson Mathew G , Bermon Stephane 
Published: February 2021

PurposeTo characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions.MethodsMarathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore(n=56) and Tsk(n=49; thermography) were measured.ResultsMost athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%–93% vs 67%–72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%–2%). Pre-race Tcorewas lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore(pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tskwas correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (−2.8±1.5% vs −1.3±1.6%, p<0.001), although not associated with performance.ConclusionMost athletes’ hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tskwas related to performance and DNF, suggesting that Tskmodulation should be incorporated into pre-race strategies.
Food insecurity is associated with mental health problems among Canadian youth
Authors: Men Fei , Elgar Frank J. , Tarasuk Valerie 
Published: February 2021

BackgroundResearch has linked food insecurity to mental health problems, though little is known about this relationship among Canadian youth. We investigate the association between food insecurity severity and mental illnesses in a nationally representative youth sample.MethodsWe sampled 55 700 youth 12–24 years from recent cycles of Canadian Community Health Survey. Household food insecurity was measured using a standard 18-item questionnaire. We fitted Poisson regressions on self-rated mental health and diagnosed mood and anxiety disorders, controlling for sociodemographic confounders. Clinical assessments of emotional distress, major depression and suicidal ideation were examined in subsamples with available data. We stratified the sample by gender, age and survey cycle to test potential demographic heterogeneity.ResultsOne in seven youth lived in marginal (5.30%), moderate (8.08%) or severe (1.44%) food insecurity. Results showed that food insecurity was associated with higher likelihood of every mental health problem examined. The association was graded, with more severe food insecurity linked to progressively worse mental health. Notably, marginal, moderate and severe food insecurity were associated with 1.77, 2.44 and 6.49 times higher risk of suicidal thoughts, respectively. The corresponding relative risk for mood disorders were 1.57, 2.00 and 2.89; those for anxiety disorders were 1.41, 1.65 and 2.58. Moderate food insecurity was more closely associated with mental health problems in 18–24 year olds than in 12–17 year olds.ConclusionsFood insecurity severity was associated with poorer mental health among Canadian youth independent of household income and other socioeconomic differences. Targeted policy intervention alleviating food insecurity may improve youth mental health.
CMTM6 and PD-L1 coexpression is associated with an active immune microenvironment and a favorable prognosis in colorectal cancer
Authors: Peng Qi-Hua , Wang Chun-Hua , Chen Hong-Min , Zhang Rong-Xin , Pan Zhi-Zhong , Lu Zhen-Hai , Wang Gao-Yuan , Yue Xin , Huang Wenlin , Liu Ran-Yi 
Published: February 2021

BackgroundCKLF-like MARVEL transmembrane domain-containing 6 (CMTM6), a programmed death-ligand 1 (PD-L1) regulator, is widely expressed in various tumors and regulates the immune microenvironment. However, its prognostic value remains controversial, and the roles of CMTM6 in colorectal cancer (CRC) are still unknown. In this study, we aimed to elaborate the expression patterns of CMTM6 and PD-L1 in CRC and investigate their relationship with the infiltration of T cells and the prognosis of patients with CRC.MethodsAnalysis of CMTM6 mRNA levels, gene ontology enrichment analysis and single-sample gene set enrichment analysis were performed in a The Cancer Genome Atlas colon cancer cohort. The expression of CMTM6 and PD-L1 and the infiltration of T cells in tumor tissues from our cohort containing 156 patients with CRC receiving adjuvant chemotherapy and 77 patients with CRC without chemotherapy were examined by immunohistochemistry assay.ResultsCMTM6 expression was upregulated in CRC compared with normal colon tissues, and CMTM6 levels were lower in advanced tumors than in early-stage tumors. High expression of CMTM6 correlated with lower pT stage and more CD4+/CD8+tumor-infiltrating lymphocytes (TILs) and predicted a favorable prognosis in CRC. PD-L1 was expressed in CRC tissues at a low level, and PD-L1 positivity in tumor stroma (PD-L1(TS)), but not PD-L1 positivity in cancer cells (PD-L1(CC)), was associated with an increased density of CD4+TILs and a favorable prognosis. The coexpression status of CMTM6 and PD-L1(TS) divided patients with CRC into three groups with low, moderate and high risks of progression and death, and patients with CMTM6High/PD-L1(TS)+status had the longest survival. Moreover, the prognostic value of CMTM6/PD-L1 expression was more significant in patients with CRC treated with adjuvant chemotherapy than in those not treated with chemotherapy.ConclusionCMTM6 has a critical impact on the immune microenvironment and can be used as an independent prognostic factor for CRC. The coexpression status of CMTM6 and PD-L1 can be used as a new classification to stratify the risk of progression and death for patients with CRC, especially for patients receiving adjuvant chemotherapy. These findings may provide insights into improving responses to immunotherapy-included comprehensive treatment for CRC in the future.