bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing the Dynamic Behavior of Strain-Gaged Force Sensors
Authors: Reuber M. , Barratt C. , Kornegay J. 
Published: April 2021

Abstract
The optimum design of strain-gaged force sensors is examined for maximum stiffness, sensitivity, and dynamic behavior. Guidelines derived from the formulation (and solution to) the classical optimization problem state that sensors with less sensitivity produce higher stiffness, sensors with small geometries will yield higher equivalent stiffness for the same sensitivity, and the preferred strain mode depends on the range of sensitivity being considered. The optimum design techniques are illustrated by analyzing the design of a sensor used to measure the forces produced in robotic water-jet cutting.
The Optimal Design of a Rotary Type Actuator for Magnetic Disk Drives
Authors: Robertson W. D. , Gabriele G. A. 
Published: April 2021

Abstract
One of the most important assemblies in any computer disk drive is the actuator which positions the read/write coil over the disk. Historically, actuators have been of the linear type, but in recent years the rotary actuator has become more popular because of its lower inertia and higher reliability. In this paper we describe the optimization of the rotary actuator geometry to achieve a minimum seek time. An objective function which approximates seek-time is derived based on the polar moment of inertia and the sweep of the actuator. A set of constraints is also developed which control mechanical resonances, skew angles, and physical position of the actuator. An optimal solution is presented as well as a sensitivity study of the final design. It is shown that the final design is relatively insensitive to changes in the problem parameters. Additionally, the sensitivity analysis reveals that a static balance constraint which is originally ignored, is not necessary.
Finite Element Analysis and Optimum Design for Precision Spindle System With Journal Bearing
Authors: Gao J. Z. , Lu X. S. 
Published: April 2021

Abstract
Spindle unit with various journal bearings is increasingly adopted in numerous machine tools. Due to overlooking the interaction between spindle and bearings in analysis and optimization leads to a less accuracy for simulating real work codition. In order to overcome this shortage, a practical coordination optimization strategy is perposed. Taking both bearing and spindle as subsystems of the overall system, using coordinator to account the interaction. Equivalent stiffness is adopted to ensure the analysis accuracy and save the computation time. An optimum design example is presented.
Optimum Design of the Crank Rocker Four Bar Mechanism for Specified Output Oscillation Angle and Timing Ratio
Authors: Suchora D. H. , Wrightson G. 
Published: April 2021

Abstract
In designing a crank rocker four bar mechanism with a uniform input rotation typical input parameters are the required total output oscillation angle and the timing ratio of the advance to return cycle time. In determining an optimum design the parameters of interest are usually the extreme transmission angles and the ratio of the longest to shortest link length occuring in the mechanism.
This work first develops an analytic construction of the link lengths and worst transmission angles based on the necessary geometry for a given output angle of oscillation and required timing ratio. The resulting equations are programmed and graphs developed which give the variation of extreme transmission angle and maximum link length ratio as a function of the specified output angle of oscillation, timing ratio, and geometric construction variables. Using these graphs a designer will be able to easily select optimum designs based on worst transmission angles and link length ratios. Examples are included.
Comparison of Modelling Methods for Hydraulic Valve Gear
Authors: Shang H. , Matthew G. K. , Luo W. 
Published: April 2021

Abstract
A combined lumped/distributed parameter model for the follower system of a hydraulically operated valve is compared to a lumped parameter model of the same system. Since previous results show excellent correspondence between the lumped/distributed parameter model and measured response, it is natural to attempt to simplify the model and to again perform a comparison. Results of several examples are shown.
Design and Mechanics of Multi-Lay Wire Strands
Authors: Velinsky S. A. 
Published: April 2021

Abstract
Wire strands and ropes have been used extensively for many years. However, the method for designing these elements remains highly dependent on the designer’s experience. In recent years, capabilities for the analysis of wire rope have progressed to a level where a re-evaluation of wire rope design is appropriate. Recently, a linearized theory has been developed that allows a relatively simple method for analyzing complex strands and wire ropes. This theory, through substantiation with experiment, is felt to be reasonably accurate for most wire rope behavior.
The present paper considers multi-lay wire strands and adds generality to the linearized theory to account for strands with any number and direction of wire lays. The geometry of wire strands is investigated in detail and a design methodology for strand geometry, including sizing the wires, is devised. The theory is then utilized to examine the effects of various design parameters on strand properties.
A Computer Based Design Methodology
Authors: Andersen K. , Cook G. E. , Strauss A. M. 
Published: April 2021

Abstract
A methodology is presented for automating or at least aiding a human designer in selection of a design concept for given design requirements. Futhermore the proposed methodology provides reasonable estimates for the various parameters of the design structure. This is accomplished by representing design requirements and design parameters as multidimensional vectors and performing appropriate interpolations to estimate feasible solutions.
Decision Making in the Choosing of New Materials From the Standpoint of Machine Structural Dynamics
Authors: Yoshimura M. 
Published: April 2021

Abstract
The use of a new material is a hopeful strategy for breaking through the barrier of improving the product performance and/or the lowering of the product manufacturing cost. However, if the definite decision making method for selection of materials has not been established, use of a new material may not result in enhancement of the product performance and / or reduction of the product manufacturing cost. This paper proposes a methodology for decision making of a material used in machine structures from the standpoint of structural dynamics. First, purposes for use of new materials and evaluative parameters for decision making of material choice are described, and fundamental knowledge and theorems for decision making are established. Then, general decision making procedures for material choice are constructed. Finally, for model cases of purposes for use of new materials, detailed decision procedures are explained using also some numerical examples.
A PHIGS-Based Graphics Input Interface for Spatial Mechanism Design
Authors: Thatch B. R. , Myklebust A. 
Published: April 2021

Abstract
Creation of input specifications for synthesis or analysis of spatial mechanisms can be a significant problem. A graphics preprocessor which interactively assists in the definition of spatial mechanism problems is described. New methods of depth cucing and six DOF data entry are presented. To achieve graphics device-independence, the proposed graphics standard PHIGS (Programmer’s Hierarchical Interactive Graphics System) is used. Examples of application are presented including generation of input commands for Integrated Mechanisms Program (IMP) and generation of input for spatial mechanism synthesis routines.
An Extended Relational Database for Conceptual Analysis of Mechanical Design
Authors: Lai K. 
Published: April 2021

Abstract
This paper presents an extended relational database system with the following features: (1) Hierarchically structured objects can be represented and manipulated integrally, (2) Design entities and design concepts can be represented and manipulated at higher abstract levels, and (3) Addition of multiple inference mechanisms to relational algebra allows intelligent solutions be developed within this robust representational environment. This Extended Relational Data Base has been successfully used to automate the conceptual analysis process of mechanical design.
Cam Motion Synthesis Using Spline Functions: Part II — Applications
Authors: Tsay D. M. , Huey C. O. 
Published: April 2021

Abstract
A series of examples is presented to illustrate the application of B-spline functions in cam motion synthesis. The use of spline functions affords a systematic, easily automated approach to the development of cam motion programs. It permits sufficient user interaction to allow refined motion programs to be obtained. It is applicable when the motion requirements can be stated as a set of discretely defined kinematic constraints. The examples indicate the versatility of the spline method by showing how it can be used for both routing and demanding cases and for an array of tasks that ordinarily cannot be accomplished by single motion synthesis technique.
Selective Precision Synthesis of the Spatial Slider Crank Mechanism for Path and Function Generation
Authors: Premkumar P. , Dhall S. R. , Kramer S. N. 
Published: April 2021

Abstract
Analysis of the RRSC spatial slider crank mechanism for path generation with prescribed input timing and for function generation are presented here in closed form. A computer aided design technique for the synthesis of the RRSC path generating and function generating mechanisms is also being presented using the Selective Precision Synthesis technique.
The analysis uses the spatial rotation matrices to obtain a fourth order polynomial for the coupler link rotations with the coefficients expressed in terms of the link lengths and input link rotation. This polynomial is solved in closed form to determine the coupler link rotations which are then used to determine the locations of the path point, the output link rotations and the displacement of the slider at the cylindrical joint.
For synthesis, nonlinear inequality constraint equations relating the generated and the desired path points or slider displacements are formulated. These constraints define accuracy neighborhoods around each of the “n” prescribed path points (or slider displacements), and are solved using the Generalized Reduced Gradient method of optimization.
Simulation of Planar Dynamic Mechanical Systems With Changing Topologies: Part I — Characterization and Prediction of the Kinematic Constraint Changes
Authors: Gilmore B. J. , Cipra R. J. 
Published: April 2021

Abstract
Due to changes in the kinematic constraints, many mechanical systems are described by discontinuous equations of motion. This paper addresses those changes in the kinematic constraints which are caused by planar bodies contacting and separating. A strategy to automatically predict and detect the kinematic constraint changes, which are functions of the system dynamics, is presented in Part I. The strategy employs the concepts of point to line contact kinematic constraints, force closure, and ray firing together with the information provided by the rigid bodies’ boundary descriptions, state variables, and reaction forces to characterize the kinematic constraint changes. Since the strategy automatically predicts and detects constraint changes, it is capable of simulating mechanical systems with unpredictable or unforeseen changes in topology. Part II presents the implementation of the characterizations into a simulation strategy and presents examples.
The Use of IGES in Rapid and Automated Design Prototyping
Authors: Kirk J. A. , Anand D. K. , Anjanappa M. , Rickert W. K. 
Published: April 2021

Abstract
The Initial Graphic Exchange Specification (IGES) for design data and the EIA standard M and G Codes for Numerically Controlled machines (N/C) is used to develop an automated interface between existing computer aided design systems and N/C manufacturing systems. The Flexible Manufacturing Protocol, developed at the University of Maryland, outlines such an interface to control automated manufacturing cells used for prototyping quick design changes. This paper demonstrates one application of the protocol, developing an automated IGES to CNC interface to control a 3 axis CNC machining center given the geometric representation of the part in IGES format. Wireframe representations of 2-1/2 dimensional parts, composed of linear elements, are the primary tools used for design representation. The automated production of the sample part, presented in this paper, demonstrates that rapid prototyping is possible using an IGES design data file as input to the protocol.
Model Based Rigid Body Guidance in Presence of Non-Convex Geometric Constraints
Authors: Ku T. S. , Ravani B. 
Published: April 2021

Abstract
This paper presents an efficient algorithm for guidance of a convex rigid body in-between non-convex polygonal objects in a Computer-Aided Design (CAD) environment. A shrinking procedure is used that separates the kinematic from the shape constraints by reducing the problem to that of guidance of a line segment in an expanded environment. A slicing technique together with an algorithm for decomposition of the interface channel between the non-convex objects is used to generate the motion program for the line segment. The results can be applied to model based guidance of mobile robots or automatic motion planning for robot manipulators.
A Multi-Level Optimization-Based Design Procedure Using Global Monotonicity Analysis
Authors: Azarm S. , Li W.-C. 
Published: April 2021

Abstract
This paper describes application of global monotonicity analysis within a decomposition framework. We present a general formulation and solution procedure, based on a bottom-level global monotornicity analysis, for a design optimization problem which is decomposed into three levels of subproblems. A well-known gear reducer example illustrates application of the method.
Optimal Synthesis of Large Systems Using Decomposition Techniques and Parallel Processing
Authors: Bhatt V. , Ragsdell K. M. 
Published: April 2021

Abstract
Various approaches to multilevel decomposition of large-scale systems are considered in this paper. A linear decomposition scheme based on the Sobieski algorithm is selected as a vehicle for automated synthesis of a complete vehicle configuration in a parallel processing environment. The research is in a developmental stage. Preliminary numerical results are presented for several example problems.
Computer Aided Design of Internal Involute Spur Gears
Authors: Tsay Chung-Biau 
Published: April 2021

Abstract
The modern theory of gearing provides principles of generation for conjugate gear tooth surfaces while computer aided design is a very powerful tool in designing a gear train with conjugate shaped tooth surfaces. It is possible to set up a mathematical model for internal involute spur gears if the theory of gearing and the concept of differential geometry together with computer aided design technique have been applied. The derived mathematical model of internal involute spur gears can be used for computer simulation of conditions of meshing, tooth contact analysis, stress analysis, dynamic analysis, lubricating analysis, and wearing analysis of the gear train.
This paper covered the solutions to the following problems : (a) method of generation for internal spur gears with conjugate tooth surfaces; (b) derivation of equations for gear tooth surfaces and their surface unit normals; and (c) computer graphics of generated internal involute spur gears.
Translational Joints in Flexible Multibody Dynamics
Authors: Hwang R. S. , Haug E. J. 
Published: April 2021

Abstract
Formulations of translational kinematic constraints between flexible bodies are developed to model deformatioin of flexible surfaces that move relative to one another. Three types of flexible translational articulated joints are presented The joint formulations are illustrated in analysis of prototype systems with translational joints. Global deformation modes and substructure local deformation modes are used and compared in numerical examples.
The Design Environment Simulator
Authors: Lesh R. , Ragsdell K. M. 
Published: April 2021

Abstract
Every engineer who has worked in industry understands what is meant by “design.” If asked, however, to explain in simple terms what engineering design is, the engineer will invariably have difficulty expressing his understanding of design. It seems that design as a process is not really understood, it is just done. Design is an art, not a science. This paper proposes a modelling method that will serve as a foundation for understanding the design process. In addition, this paper describes an experimental method for exploring design that may validate the model and provide the data necessary to use the model.
Outcomes and surgical management of persistent fetal vasculature
Authors: Khandwala Nikhila , Besirli Cagri , Bohnsack Brenda L 
Published: April 2021

ObjectiveTo analyse outcomes in different forms of persistent fetal vasculature (PFV).Methods and analysisRetrospective cohort study at a university-based practice of children presenting with PFV between 2011 and 2020. Exclusion criteria was surgical management outside of our institution and follow-up less than 1 month. Wilcoxon and Student’s t-tests were used for statistical analysis.ResultsForty-six eyes of 45 patients presented with PFV at 16.7±31.3 (median 2.8) months old with 32.6±29.8 (median 22.5) months of follow-up. Types of PFV included: mild combined anterior-posterior (23 eyes, 50%), severe combined anterior-posterior (18 eyes, 39%), severe anterior (3 eyes, 7%), mild anterior (1 eye, 2%) and posterior (1 eye, 2%). Thirty-two eyes (70%) underwent PFV surgical correction; lensectomy (13 mild combined), vitrectomy (3 mild combined), sequential lensectomy then vitrectomy (3 severe combined), combined lensectomy-vitrectomy (11 severe anterior or severe combined), laser retinopexy (1 mild combined). Five eyes required additional vitrectomy surgery for retinal detachment, fold or cyclitic membrane. Nine eyes developed glaucoma, six requiring Intraocular pressure (IOP)-lowering surgery. At final follow-up, 32 eyes had at least form vision and 6 eyes were aversive to light. Eight eyes, all which were severe combined, and four that did not undergo PFV surgery, were unable to detect light due to phthisis bulbi (7) and optic nerve hypoplasia (1).ConclusionsClassification of PFV is important in determining surgical approach with severe cases often requiring both lensectomy and vitrectomy for optimal anatomic and functional outcomes.
Potential of community-based risk estimates for improving hospital performance measures and discharge planning
Authors: Reid Michael , Kephart George , Andreou Pantelis , Robinson Alysia 
Published: April 2021

BackgroundRisk-adjusted rates of hospital readmission are a common indicator of hospital performance. There are concerns that current risk-adjustment methods do not account for the many factors outside the hospital setting that can affect readmission rates. Not accounting for these external factors could result in hospitals being unfairly penalized when they discharge patients to communities that are less able to support care transitions and disease management. While incorporating adjustments for the myriad of social and economic factors outside of the hospital setting could improve the accuracy of readmission rates as a performance measure, doing so has limited feasibility due to the number of potential variables and the paucity of data to measure them. This paper assesses a practical approach to addressing this problem: using mixed-effect regression models to estimate case-mix adjusted risk of readmission by community of patients’ residence (community risk of readmission) as a complementary performance indicator to hospital readmission rates.MethodsUsing hospital discharge data and mixed-effect regression models with a random intercept for community, we assess if case-mix adjusted community risk of readmission can be useful as a quality indicator for community-based care. Our outcome of interest was an unplanned repeat hospitalisation. Our primary exposure was community of residence.ResultsCommunity of residence is associated with case-mix adjusted risk of unplanned repeat hospitalisation. Community risk of readmission can be estimated and mapped as indicators of the ability of communities to support both care transitions and long-term disease management.ConclusionContextualising readmission rates through a community lens has the potential to help hospitals and policymakers improve discharge planning, reduce penalties to hospitals, and most importantly, provide higher quality care to the people that they serve.
How verbal variety kills comprehension
Authors: Yaffe Philip 
Published: April 2021

Each "Communication Corner" essay is self-contained; however, they build on each other. For best results, before reading this essay and doing the exercise, go to the first essay "How an Ugly Duckling Became a Swan," then read each succeeding essay.
The purpose of expository (non-fiction) writing and speaking is usually to inform or instruct. To do either successfully, you must present your ideas more than once. Otherwise, people who read it or hear it, even if they completely understand it at the moment, over time (often a very short time) will either confuse it or forget it. Presenting information and ideas more than once is not simply a matter of saying the same things the same way two or three times. It is more subtle than that.