bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Performance Enhancement of a Flapping Foil Energy Harvester Using Circulation Control
Authors: Shi Fangrui , Sun Xiaojing 
Published: February 2021

Abstract
Oscillating motion, an effective way to harvest energy, has gradually become a hotspot in bionic motion research in recent years. Means of improving the energy-extraction efficiency of a flapping foil harvester have long been a focus of researchers. This paper proposes a new flapping foil harvester with circulation control and explores the effects of different parameters on its energy-extraction capacity to improve efficiency and achieve lowest cost. Setting the injection ports on the upper and lower surfaces near the trailing edge of the foil and implementing injection control during motion, the effects of the location of the injection port, pitching amplitude, momentum coefficient, reduced frequency, and jet mode on the circulation control flapping foil are systematically investigated under the condition of a Reynolds number of 13,800. The results show that circulation control can enhance the energy-extraction efficiency of a flapping foil across a wide range of parameters, in which the location of the injection port and momentum coefficient have the most obvious influence on efficiency, followed by pitching amplitude and reduced frequency. In addition, the jet mode is a crucial factor affecting net efficiency. Relative to the constant mode, the triangular mode of circulation control has the lowest energy consumption, and the net energy-extraction efficiency reaches up to 38.77% under a reduced frequency of 0.12, which is 22.24% higher than that of the plain flapping foil.
A Sensor Simulation Framework for Training and Testing Robots and Autonomous Vehicles
Authors: Elmquist Asher , Serban Radu , Negrut Dan 
Published: February 2021

Abstract
Computer simulation can be a useful tool when designing robots expected to operate independently in unstructured environments. In this context, one needs to simulate the dynamics of the robot’s mechanical system, the environment in which the robot operates, and the sensors which facilitate the robot’s perception of the environment. Herein, we focus on the sensing simulation task by presenting a virtual sensing framework built alongside an open-source, multi-physics simulation platform called Chrono. This framework supports camera, lidar, GPS, and IMU simulation. We discuss their modeling as well as the noise and distortion implemented to increase the realism of the synthetic sensor data. We close with two examples that show the sensing simulation framework at work: one pertains to a reduced scale autonomous vehicle and the second is related to a vehicle driven in a digital replica of a Madison neighborhood.
Influence of Mean Strain on Fatigue Life of Stainless Steel in Pressurized Water Reactor Water Environment
Authors: Kamaya Masayuki 
Published: February 2021

Abstract
The Influence of application of the mean strain on the fatigue life was investigated for Type 316 stainless steel in the simulated pressurized water reactor (PWR) primary water environment. Low-cycle fatigue tests were conducted for a constant mean strain by controlling the strain range to be 1.2%. The applied strain rates were 0.4%/s, 0.004%/s, or 0.001%/s. The applied mean strain was 15% in nominal strain. In addition, cold worked specimens were also used for the tests without applying the mean strain. The cold working simulated the application of mean strain without an increase in surface roughness due to the application of plastic deformation. By inducing the cold working at low temperature, the influence of martensitic phase on the fatigue life was also examined. The PWR water environment reduced the fatigue life and the degree of the fatigue life reduction was consistent with the prediction model of the code issued by the Japan Society of Mechanical Engineers (JSME) and NUREG/CR-6909 Rev. 1. Increases in the maximum peak stress and stress range caused by cold working did not cause any apparent change in the fatigue life. It was revealed that the 10.5 wt% martensitic phase and the increase in the surface roughness caused by the application of 15% mean strain did not bring about further fatigue life reduction. The current JSME and NUREG/CR-6909 models were applicable for predicting the fatigue in the PWR water environment even when the mean strain or cold working was applied.
Deformation Behavior of Single Prismatic Battery Cell Cases and Cell Assemblies Loaded by Internal Pressure
Authors: Nguyen T. D. , Deng J. , Robert B. , Chen W. , Siegmund T. 
Published: February 2021

Abstract
The safety of electrochemical energy storage system depends on the structural integrity of the call containment. Nominal values of cell case dimensions and material properties are the standard inputs for the mechanical analysis of prismatic lithium-ion batteries. However, such data usually do not account for any considerations on the influence of the manufacturing processes of the cell case. This study investigates the effects of the cell wall thickness and elastic modulus, resulting from deep-drawing process, on the cell and cell assembly response. It is found that the deep-drawing process degrades Young’s modulus relative to standard values and leads to a spatial variation in the wall thickness of the cell case. The use of actual cell case material properties and cell wall thickness values is required to obtain validated finite element models of the battery cell case. Using experiments on internal pressure loaded single battery cells and finite element computations, it is demonstrated that the use of nominal cell casing characteristics significantly underestimates the resistance provided by the cell case to counter swelling of the active battery components.
A Parametric Level Set Method for Topology Optimization Based on Deep Neural Network
Authors: Deng Hao , To Albert C. 
Published: February 2021

Abstract
This paper proposes a new parametric level set method for topology optimization based on deep neural network (DNN). In this method, the fully connected DNN is incorporated into the conventional level set methods to construct an effective approach for structural topology optimization. The implicit function of level set is described by fully connected DNNs. A DNN-based level set optimization method is proposed, where the Hamilton–Jacobi partial differential equations (PDEs) are transformed into parametrized ordinary differential equations (ODEs). The zero-level set of implicit function is updated through updating the weights and biases of networks. The parametrized reinitialization is applied periodically to prevent the implicit function from being too steep or too flat in the vicinity of its zero-level set. The proposed method is implemented in the framework of minimum compliance, which is a well-known benchmark for topology optimization. In practice, designers desire to have multiple design options, where they can choose a better conceptual design base on their design experience. One of the major advantages of the DNN-based level set method is capable to generate diverse and competitive designs with different network architectures. Several numerical examples are presented to verify the effectiveness of the proposed DNN-based level set method.
Decision-Making Under Uncertainty for a Digital Thread-Enabled Design Process
Authors: Singh Victor , Willcox Karen E. 
Published: February 2021

AbstractDigital thread is a data-driven architecture that links together information from all stages of the product lifecycle. Despite increasing application in manufacturing, maintenance/operations, and design related tasks, a principled formulation of analyzing the decision-making problem under uncertainty for the digital thread remains absent. The contribution of this article is to present a formulation using Bayesian statistics and decision theory. First, we address how uncertainty propagates in the product lifecycle and how the digital thread evolves based on the decisions we make and the data we collect. By using these mechanics, we explore designing over multiple product generations or iterations and provide an algorithm to solve the underlying multistage decision problem. We illustrate our method on an example structural design problem where our method can quantify and optimize different types and sequences of decisions, ranging from experimentation, manufacturing, and sensor placement/selection, to minimize total accrued costs.
A Real-Time Laser-Based Detection System for Measurement of Delineations of Moving Vehicles
Authors: Cheng Harry H. , Shaw Benjamin D. , Palen Joe , Larson Jonathan E. , Hu Xudong , Van Katwyk Kirk 
Published: February 2021

Abstract
In current practice, quantitative traffic data are most commonly acquired from inductive loops. In addition, video-image processing or time-of-flight laser systems can be used. These methods all have problems associated with them. We have developed a non-intrusive laser-based detection system for measurement of vehicle travel time. The basic detector unit consists of a fan angle laser and a photodetector array positioned above the plane of detection. This detection system is able to determine the length and width of moving objects in real time with high resolution. This information is used to differentiate similar objects and can be used later for re-identification of individual objects or object groups, providing a real measure of travel time between detection sites.
Design FMEA for Mechatronic Systems Using Bayesian Network Causal Models
Authors: Lee Burton Hoyt 
Published: February 2021

Abstract
This paper presents the use of Bayesian networks as a methodology for eliciting and encoding Failure Modes and Effects Analysis (BN-FMEA) models of mechatronic systems. The method uses probabilistic directed acyclic graphs to construct causal dependency structures between functional, behavioral and structural random variables of the physical system. Default apriori probabilities and conditional probability tables are generated and attached to the graph structure for post-design evaluation by diagnostic engineers. BN-FMEA provides a language for design teams to articulate — with less ambiguity and greater precision — component failure cause-effect relationships across sub-systems. An example of an inkjet printer illustrates how BN-FMEA can be applied. The approach supports traditional FMEA objectives — identification of system failure modes, provides improved knowledge representation and inferencing power over spreadsheets, and is generally applicable to the class of industry- and government-standard FMEA spreadsheets and tables in use today. Finally, BN-FMEA is presented as a basis for improved integration of design and diagnostic modeling of mechatronic systems.
Orientation Workspace Analysis of 6-DOF Parallel Manipulators
Authors: Bonev Ilian A. , Ryu Jeha 
Published: February 2021

Abstract
This paper presents a new discretization method for the computation of the orientation workspace of 6-rDOF parallel manipulators, defined as the set of all attainable orientations of the mobile platform about a fixed point. The method is based on the use of a modified set of Euler angles and a particular representation of the orientation workspace. In addition, a direct method is suggested for the computation of the projected orientation workspace, defined as the set of all possible directions of the approach vector of the mobile platform. Alternative ways of computing these two types of workspaces are also discussed with typical examples.
Experimental Investigation of Factors Influential for the Flexible Blade Based Prototyping Process
Authors: de Smit Bram , Broek Johan J. , Horváth Imre 
Published: February 2021

Abstract
Due to the need for large numbers of layers and size limitations, current layered manufacturing technologies are not suitable for the fabrication of large sized free-form objects. For this purpose a novel technology of thick layered object manufacturing is being developed, based on higher order approximation of the initial geometry, and the application of a flexible curved cutting tool. The method allows us to produce physical prototypes with less or without any finishing. The technology of cutting foams by means of a heated flexible blade in polystyrene foam offers new possibilities. However to achieve the optimum output, optimization of the process parameters is needed. In this paper a closer look is taken into the process characteristics and the influential factors which are decisive for productive cutting. The authors summarize the results of the executed experimental tests. In these experiments the values of the most influential parameters were systematically changed and the effects were carefully investigated. The first results indicate that the cutting technology is practically feasible, but further research is needed in order to achieve a balanced optimization of the technology from all aspects.
Genetic Algorithms in Fuzzy Engineering Design
Authors: Schleiffer Ralf , Sebastian Hans-Jürgen , Antonsson Erik K. 
Published: February 2021

Abstract
Problems in the field of engineering design represent an important class of real world problems that typically require a fuzzy and imprecise representation. This article presents and discusses a new approach to model this type of problem, by incorporating linguistic descriptions together with a variety of user-defined trade-off strategies. An interactive computer application is introduced, using stochastic optimization to solve the design task by producing a specially desired output under the given environmental conditions which are partly caused by the personal preferences of the engineer and by the expectations of the customer. It utilizes a randomized evolutionary technique, made suitable for the class of problems at hand, to generate and to optimize design solutions that are later identified by a clustering algorithm. Moreover test problems that were solved by the application are considered. In all cases the good solutions were obtained by evaluating only an extremely small fraction of all possible designs.
Facilitating Tacit Knowledge Capture and Reuse in Conceptual Design Activities
Authors: Yen Samuel J. , Fruchter Renate , Leifer Larry J. 
Published: February 2021

Abstract
This paper discusses the approach and analysis of an empirical study that supports the hypothesis that concept generation and development occur most frequently in informal media where design capture tools are the weakest. This statement has strong implications for the capture and reuse of design knowledge because conceptual design generates the majority of initial ideas and directions that guide the course of the project. Many important decisions are made along with rationales that support these decisions, but since these rationales are expressed in design activities such as brainstorming sessions and conversations, the design rationale is rarely captured and the knowledge is lost. While traditional product documentation captures explicit knowledge such as requirements, specifications, and design decisions, often the contextual or tacit knowledge of the design group is lost. The paper concludes with a description of a computer-mediated system, called “Recall”, that addresses the results of our findings by providing a means of capturing and indexing informal media to facilitate design reuse.
Modeling the Vibratory Drilling Process
Authors: Batzer Stephen A. , Gouskov Alexander M. , Voronov Sergey A. 
Published: February 2021

Abstract
The dynamic behavior of deep-hole vibratory drilling is analyzed. The mathematical model presented allows the determination of axial tool and workpiece displacements and cutting forces for significant dynamic system behavior such as the entrance of the cutting tool into workpiece material and exit. Model parameters include the actual rigidity of the tool and workpiece, time-varying chip thickness, time lag for chip formation due to tool rotation and possible disengagement of drill cutting edges from the workpiece due to tool and/or workpiece axial vibrations. The main features of this model are its nonlinearity and inclusion of time lag differential equations which require numeric solutions. The specific cutting conditions (feed, tool rotational velocity, amplitude and frequency of forced vibrations) necessary to obtain discontinuous chips and reliable removal are determined. The stability conditions of excited vibrations are also investigated. Calculated bifurcation diagrams make it possible to derive the domain of system parameters along with the determination of optimal cutting conditions.
A tale of five enclaves: Mineral perspectives on origins of mafic enclaves in the Tuolumne Intrusive Complex
Authors: Barnes C.G. , Werts K. , Memeti V. , Paterson S.R. , Bremer R. 
Published: February 2021

AbstractThe widespread occurrence of mafic magmatic enclaves (mme) in arc volcanic rocks attests to hybridization of mafic-intermediate magmas with felsic ones. Typically, mme and their hosts differ in mineral assemblage and the compositions of phenocrysts and matrix glass. In contrast, in many arc plutons, the mineral assemblages in mme are the same as in their host granitic rocks, and major-element mineral compositions are similar or identical. These similarities lead to difficulties in identifying mixing end members except through the use of bulk-rock compositions, which themselves may reflect various degrees of hybridization and potentially melt loss. This work describes the variety of enclave types and occurrences in the equigranular Half Dome unit (eHD) of the Tuolumne Intrusive Complex and then focuses on textural and mineral composition data on five porphyritic mme from the eHD. Specifically, major- and trace-element compositions and zoning patterns of plagioclase and hornblende were measured in the mme and their adjacent host granitic rocks. In each case, the majority of plagioclase phenocrysts in the mme (i.e., large crystals) were derived from a rhyolitic end member. The trace-element compositions and zoning patterns in these plagioclase phenocrysts indicate that each mme formed by hybridization with a distinct rhyolitic magma. In some cases, hybridization involved a single mixing event, whereas in others, evidence for at least two mixing events is preserved. In contrast, some hornblende phenocrysts grew from the enclave magma, and others were derived from the rhyolitic end member. Moreover, the composition of hornblende in the immediately adjacent host rock is distinct from hornblende typically observed in the eHD. Although primary basaltic magmas are thought to be parental to the mme, little or no evidence of such parents is preserved in the enclaves. Instead, the data indicate that hybridization of already hybrid andesitic enclave magmas with rhyolitic magmas in the eHD involved multiple andesitic and rhyolitic end members, which in turn is consistent with the eHD representing an amalgamation of numerous, compositionally distinct magma reservoirs. This conclusion applies to enclaves sampled &lt;30 m from one another. Moreover, during amalgamation of various rhyolitic reservoirs, some mme were evidently disrupted from a surrounding mush and thus carried remnants of that mush as their immediately adjacent host. We suggest that detailed study of mineral compositions and zoning in plutonic mme provides a means to identify magmatic processes that cannot be deciphered from bulk-rock analysis.
Comparison of rectal and axillary temperature measurements in preterm newborns
Authors: McCarthy Lisa K , O’Donnell Colm Patrick Finbarr 
Published: February 2021

ObjectiveTo compare rectal and axillary temperatures in preterm newborns on admission to the neonatal intensive care unit (NICU).DesignSecondary analysis of data collected in a randomised controlled trial (RCT).SettingMaternity hospital, level 3 NICU.PatientsSeventy-two newborns <31 weeks who were enrolled in the BAMBINO RCT (A randomised trial of exothermic mattresses to prevent heat loss in preterm infants at birth, ISRCTN31707342).InterventionsNewborns were placed in polyethylene bags and were randomised to placement on exothermic mattresses, or not in the delivery room. All infants had rectal and axillary temperatures measured in immediate succession using a digital thermometer on NICU admission.Outcome measuresAdmission rectal and axillary temperatures.ResultsMean (SD) gestational age was 28 (2) weeks and birth weight was 1138 (374) g. Mean rectal-axillary temperature difference was 0.1 (0.5°C) (range −1.4°C to +1.5°C). Rectal and axillary temperatures differed by ≥0.5°C in 18/72 (25%) infants; axillary temperature was higher than rectal in 6 (8%) and lower in 12 (17%). There was a positive linear relationship between rectal and axillary measurements (Pearson’s correlation R=0.84). Applying the Bland-Altman technique, the width of 95% prediction interval was 1.8°C (−0.8°C to 1.0°C) implying that rectal and axillary measurements may vary by up to 1.0°C. Axillary temperature had a sensitivity of 65% when used to detect rectal hyperthermia and 100% sensitivity for hypothermia.ConclusionPaired rectal and axillary temperature measurements in preterm newborns on NICU admission vary significantly. Axillary temperature was sensitive at detecting rectal hypothermia but not hyperthermia. Axillary temperature may not be an accurate proxy for rectal temperature measurement in all preterm newborns on NICU admission.
Effect of critical illness insurance on the medical expenditures of rural patients in China: an interrupted time series study for universal health insurance coverage
Authors: Zhong Zhengdong , Jiang Junnan , Chen Shanquan , Li Lu , Xiang Li 
Published: February 2021

ObjectiveThe objective of this study is to determine if critical illness insurance (CII) promotes the universal health coverage to reduce out-of-pocket (OOP) medical expenditures and improve the effective reimbursement rate (ERR) in rural China.Study designThe 5-year monthly hospitalisation data, starting 2 years before the CII (ie, the ‘intervention’) began, were collected. Interrupted time series analysis models were used to evaluate the immediate and gradual effects of CII on OOP payment and ERR.SettingThe study was conducted in Xiantao County, Hubei Province, China.ParticipantsA total of 511 221 inpatients within 5 years were included in the analysis.ResultsIn 2016, 100 288 patients received in-patient services, among which 4137 benefited from CII. After the implementation of CII, OOP expenses increased 32.2% (95% CI 24.8% to 39.5%, p<0.001). Compared with the preintervention periods, the trend changes decline at a rate of 0.7% per month after the implementation of CII. Similarly, a significant decrease was observed in log ERR after the intervention started. The rate of level change is 16% change (95% CI −20.0% to −12.1%, p<0.001).ConclusionCII did not decrease the OOP payments of rural inpatients in 2011–2016 periods. The limited extents of population coverage and financing resources can be attributed to these results. Therefore, the Chinese government must urgently raise the funds of CII and improve the CII policy reimbursement rate.