bluuebunny/crossref_metadata_2025_split huggingface dataset:
High silicon concentrations in grasses are linked to environmental conditions and not associated with C4 photosynthesis
Authors: Brightly William H. , Hartley Sue E. , Osborne Colin P. , Simpson Kimberley J. , Strömberg Caroline A. E. 
Published: September 2020

AbstractThe uptake and deposition of silicon (Si) as silica phytoliths is common among land plants and is associated with a variety of functions. Among these, herbivore defense has received significant attention, particularly with regard to grasses and grasslands. Grasses are well known for their high silica content, a trait which has important implications ranging from defense to global Si cycling. Here, we test the classic hypothesis that C4 grasses evolved stronger mechanical defenses than C3 grasses through increased phytolith deposition, in response to extensive ungulate herbivory (“C4‐grazer hypothesis”). Despite mixed support, this hypothesis has received broad attention, even outside the realm of plant biology. Because C3 and C4 grasses typically dominate in different climates, with the latter more abundant in hot, dry regions, we also investigated the effects of water availability and temperature on Si deposition. We compiled a large dataset of grasses grown under controlled environmental conditions. Using phylogenetically informed generalized linear mixed models and character evolution models, we evaluated whether photosynthetic pathway or growth condition influenced Si concentration. We found that C4 grasses did not show consistently elevated Si concentrations compared with C3 grasses. High temperature treatments were associated with increased concentration, especially in taxa adapted to warm regions. Although the effect was less pronounced, reduced water treatment also promoted silica deposition, with slightly stronger response in dry habitat species. The evidence presented here rejects the “C4‐grazer hypothesis.” Instead, we propose that the tendency for C4 grasses to outcompete C3 species under hot, dry conditions explains previous observations supporting this hypothesis. These findings also suggest a mechanism via which anthropogenic climate change may influence silica deposition in grasses and, by extension, alter the important ecological and geochemical processes it affects.
High‐density mapping validation of antral pulmonary vein isolation and posterior wall isolation created with a new cryoballoon ablation system: The first reported case
Authors: Moltrasio Massimo , Kochi Adriano N. , Fassini Gaetano , Riva Stefania , Tundo Fabrizio , Tondo Claudio 
Published: September 2020

AbstractCryoballoon ablation is a recognized and widespread method for pulmonary vein isolation. For many years the impossibility of using it to create additional lines was considered a drawback of this approach. However, recently, the technique was adapted to allow the creation of rooflines, and potentially also inferior lines. In this article, we present the first reported case of a patient submitted to pulmonary vein isolation plus posterior wall isolation using the novel Boston POLAR X™ cryoballoon exclusively. To confirm the quality of the lesions, the patient underwent pre and postablation high‐density mapping.
Investigations on the process and product parameters of radio frequency‐induced accelerated aged paddy
Authors: Iftikhar Farheena , Hussain Syed Zameer , Naseer Bazila , Nidoni Uday Kumar , Naik Haroon R. 
Published: September 2020

AbstractThe present study was conducted with an aim to reduce the aging time of paddy through the application of radio frequency (RF) heating. The effects of paddy moisture content and RF exposure time on various quality attributes of rice were investigated using response surface methodology. Both moisture content and RF exposure time were set at five levels between 11–21.5% and 17–208 min, respectively. The process variables significantly affected all the quality parameters except kernel elongation ratio, non‐reducing sugars, trough viscosity, hardness, and stickiness. Models obtained for these parameters were highly significant (p ≤ .0027) with high coefficient of determination (R2 ≥ .893). Optimum conditions to induce accelerated aging in paddy using RF heating were 45 min of RF exposure time at 16.3% moisture content of paddy. The outcome of the study could be very useful for researchers in future to plan in depth studies on accelerated aging of paddy through RF heating.Practical ApplicationsFreshly harvested rice is less preferred by consumers because of its poor cooking properties. However, natural aging takes a long time to induce desirable quality changes in rice, while accelerating aging improves the quality of rice more rapidly. However, all the accelerated aging methods reported so far have many limitations such as restricted penetration power, lower efficiency, and slow heating. Radio frequency (RF) heating is undoubtedly superior to all such heating methods due to its deeper penetration power, faster heating, and suitability to process bulk materials. The outcome of this study in terms of predictive models and optimized conditions of RF exposure time and moisture content, if properly manipulated can help to induce desirable quality changes in rice within the shortest period of time. Inference drawn from the present study was that the RF heating can emerge as a novel approach to induce accelerating aging in rice.
Integrating Digital Technology in an Intensive, Fully Online College Course for Japanese Beginning Learners: A Standards‐Based, Performance‐Driven Approach
Authors: SATO ERIKO , CHEN JULIAN CHENG CHIANG , JOURDAIN SARAH 
Published: September 2020

AbstractThe development of distance learning courses for less commonly taught languages (LCTLs) often meets with instructional challenges, especially for Asian LCTLs with their distinct non‐Roman characters and structures. This study documents the implementation of a fully online, elementary Japanese course at Stony Brook University. The curriculum was designed around the American Council on the Teaching of Foreign Languages's (ACTFL) World‐Readiness Standards for Learning Languages; performance‐driven assessments; and task‐supported, technology‐enhanced principles. Asynchronous and synchronous tools were incorporated to facilitate task delivery and reduce the virtual isolation of learners. A simulated Oral Proficiency Interview (OPI) was conducted for the online students in order to compare their oral performance with that of the face‐to‐face (F2F) cohort in the preceding semester. Quantitative results show that online students outperformed their F2F counterparts in most of the Integrated Performance Assessment's scoring criteria, with a statistically significant difference in the criterion “Communication strategies.” Survey results indicate students’ positive attitudes toward language gains and corroborate the qualitative results gleaned from student learning journals and survey responses: Students’ sense of isolation was replaced by a sense of co‐presence. We conclude that developing an online LCTL course, though challenging, is feasible and maximizes outcomes through the synergy of multimodal digital platforms, and a standards‐based, task‐driven curriculum design.
Equivalent Linearization of Bladed Disk Assemblies With Friction Nonlinearities Under Random Excitation
Authors: Förster Alwin , Panning-von Scheidt Lars , Wallaschek Jörg 
Published: September 2020

AbstractThis article addresses the vibrational behavior of bladed disk assemblies with nonlinear shroud coupling under random excitation. In order to increase the service life and safety of turbine blades, intense calculations are carried out to predict the vibrational behavior. The use of friction dampers for energy dissipation and suppression of large amplitudes makes the mechanical system nonlinear, which complicates the calculations. Depending on the stage, different types of excitation can occur in a turbine, from clearly defined deterministic to random excitation. So far, the latter problem has only been dealt with to a limited extent in the literature on turbomachinery. Nevertheless, there are in general different approaches and methods to address this problem most of which are strongly restricted with regard to the number of degrees-of-freedom (DOF). The focus of this paper is the application of an equivalent linearization method (ELM) to calculate the stochastic response of an academic model of a bladed disk assembly under random excitation. The nonlinear contact is modeled both with an elastic Coulomb-slider and a Bouc–Wen formulation to reproduce the hysteretic character of a friction nonlinearity occurring in the presence of a friction damper. Both the excitation and the response are limited to mean-free, stationary stochastic processes, which means that the stochastic moments do not change over time. Unlike previous papers on this topic, the calculations are performed on a full bladed disk assembly in which each segment is approximated with several degrees-of-freedom.
Mining Design Heuristics for Additive Manufacturing Via Eye-Tracking Methods and Hidden Markov Modeling
Authors: Mehta Priyesh , Malviya Manoj , McComb Christopher , Manogharan Guha , Berdanier Catherine G. P. 
Published: September 2020

Abstract
In this research, we collected eye-tracking data from nine engineering graduate students as they redesigned a traditionally manufactured part for additive manufacturing (AM). Final artifacts were assessed for manufacturability and quality of final design, and design behaviors were captured via the eye-tracking data. Statistical analysis of design behavior duration shows that participants with more than 3 years of industry experience spend significantly less time removing material and revising than those with less experience. Hidden Markov modeling (HMM) analysis of the design behaviors gives insight to the transitions between behaviors through which designers proceed. Findings show that high-performing designers proceeded through four behavioral states, smoothly transitioning between states. In contrast, low-performing designers roughly transitioned between states, with moderate transition probabilities back and forth between multiple states.
Assembly Variation Analysis of Incompletely Positioned Macpherson Suspension Systems Considering Vehicle Load Change
Authors: Niu Zhihua , Jin Sun , Li Zhimin 
Published: September 2020

Abstract
The assembly precision of wheel alignment parameters is vital to vehicle handling stability. Due to the vertical wheel displacement and compliant components in suspension systems, it is difficult to assemble qualified vehicles with proper wheel alignment parameters. In the assembly shop of the automobile factory, the adjustment of wheel alignment parameters is the most time-consuming process because it relies on trial and error. In order to provide a theoretical guidance to the precision control of wheel alignment parameters, this paper extends the theory of equilibrium equations of incremental forces (EEIF) to 3D compliant mechanisms. Constraint equations of kinematic joints are adopted to express the spatial relationships of different parts. A couple of fixed and floating joint coordinate systems (CSs) are used together to represent deviations of compliant components. The impacts of suspension part deviations on vertical wheel displacement and assembly deformations are well illustrated by such approach. Accuracy of the proposed method is verified by comparing with ADAMS simulation. The results show that the error rates of the 3D EEIF method are less than 5%. Furthermore, statistical assembly variation analysis of a Macpherson suspension is accomplished by using the proposed method and an optimized process strategy is put forward.
A Simplified Analytical Model for Estimation of the Initial Waterhammer Pressure and Force on a Circular Tube
Authors: Jo Jong Chull , Jeong Jae Jun , Moody Frederick J. 
Published: September 2020

Abstract
A simplified analytical model is developed for estimating the initial waterhammer pressure and force on a circular tube when a plane decompression wave, parallel to its axis, passes over it. The simplified analysis superimposes the solutions for a plane pressure wave traveling at sound speed in the surrounding water, and two-dimensional solution to the wave equation in cylindrical coordinates, with a nonflow boundary condition across the tube boundary at a fixed radius. The analytical method is compared to the computational fluid dynamics (CFD) approach by applying to predict the initial waterhammer pressure and force on the closest tube to the feedwater nozzle of a geometrically simplified nuclear steam generator (SG) analysis model, caused by a feedwater pipe break (FWPB). As the result, it is found that the simplified analytical model, while not matching results of the CFD calculations with precise accuracy, does confirm the nature of the waterhammer impact pressure loads on the SG tubes.
An Image-Based Approach to Variational Path Synthesis of Linkages
Authors: Deshpande Shrinath , Purwar Anurag 
Published: September 2020

Abstract
This paper brings together computer vision, mechanism synthesis, and machine learning to create an image-based variational path synthesis approach for linkage mechanisms. An image-based approach is particularly amenable to mechanism synthesis when the input from mechanism designers is deliberately imprecise or inherently uncertain due to the nature of the problem. In addition, it also lends itself naturally to the creation of a unified approach to mechanism synthesis for different types of mechanisms, since for example, images are formed from a collection of pixels, which themselves could be generated from a four-bar or six-bar. Path synthesis problems have generally been solved for a set of precision points on the intended path such that the designed mechanism passes through those points. This approach usually leads to a small set of over-fitted solutions to particular precision points. However, most kinematic synthesis problems are concept generation problems, where a designer cares more about generating a large number of plausible solutions, which could reach given precision points only approximately. This paper models the input curve as a probability distribution of image pixels and employs a probabilistic generative model to capture the inherent uncertainty in the input. In addition, it gives feedback on the input quality and provides corrections for a more conducive input. The image representation allows for capturing local spatial correlations, which plays an important role in finding a variety of solutions with similar semantics as the input curve. This approach is also conducive to implementation for pressure-sensitive touch-based design interfaces, where the input is not a zero-thickness curve, but the sweep of a small patch on the finger.
Relation Between Neck Skin Temperature Measurement and Carotid Artery Stenosis: In-Vitro Evaluation
Authors: Saxena Ashish , Ng Eddie Yin Kwee , Canchi Tejas , Tee Jun Jie , Ng Lip Koon 
Published: September 2020

Abstract
Carotid artery stenosis is a form of atherosclerosis, where thrombus formation restricts the passage of blood through the carotid artery leading to irreversible damage in the brain tissue. The presence of stenosis in the carotid artery results in abnormal temperature maps on the external skin surface, which can be captured and quantified using noncontact/noninvasive infrared (IR) thermal imaging/thermography. In this study, a thermally charged in vitro carotid artery flow loop, using 0% and 75% stenosis models, was designed to study the thermal effect on the external skin surface. The carotid artery flow was encapsulated with polydimethylsiloxane (PDMS) resembling neck tissue, of which the external surface temperature maps were studied using IR thermography. Using the mean temperature as a threshold value, the resultant thermal image was processed and normalized. Between the two stenosis models, disruption in the thermal features corresponding to the presence of stenosis was observed. The method described in this study paves the path to experimentally study the thermal effect of the presence of stenosis in the carotid artery.
Gateway Configuration for Rapid Pick-and-Place Operations of 2-Degrees-of-Freedom Parallel Robots
Authors: Martin-Parra Andrea , Rodriguez-Rosa David , Juarez-Perez Sergio , Rubio-Gomez Guillermo , Gonzalez-Rodriguez Antonio , Castillo-Garcia Fernando J. 
Published: September 2020

Abstract
This article presents a new assembling for 2 degrees-of-freedom (DOFs) parallel robots for executing rapid pick-and-place operations with low energy consumption. A conventional design of 2-DOF parallel robots is based on five-bar mechanisms. Collisions between links are highly possible, restricting the end-effector workspace and/or increasing the trajectory time to avoid collisions. In this article, an alternative assembling for preventing collisions is presented. This novel assembling allows exploring the difference between the four five-bar mechanism configurations for the same position of the end-effector. Some of these configurations yield to lower time and/or lower energy consumption for the same motorization. First, a dynamic model of the robot has been developed using matlab® and simulink® and validated by comparison with the results obtained by adams® software. A robust cascade PD regulator for controlling joint coordinates has been tuned providing a high accurate end-effector positioning. Finally, simulation results of four configurations are presented for executing controlled maneuvers. The obtained results demonstrate that the conventional configuration is the worst one in terms of trajectory time or energy consumption and, conversely, the best one corresponds to an uncommonly used configuration. A workspace map where all configurations provide faster maneuvers has been obtained in terms of Jacobian matrix and mechanism elbows distance. The results presented here allow designing a rapid manipulator for pick-and-place operations.
Cosine Error-Free Metrology Tool Path Planning for Thickness Profile Measurements
Authors: Guo Xiangyu , Lee ChaBum 
Published: September 2020

Abstract
This paper presents a novel thickness profile measuring system that measures double-sided thin pipe wall surfaces in a non-contact, continuous, cosine error-free, and fast manner. The surface metrology tool path was developed to align the displacement sensors always normal to the double-sided surfaces to remove cosine error. A pair of capacitive-type sensors that were placed on the rotary and linear axes simultaneously scans the inner and outer surfaces of thin walls. Because the rotational error of the rotary axis can severely affect the accuracy in thickness profile measurement, such error was initially characterized by a reversal method. It was compensated for along the rotational direction while measuring the measurement target. Two measurement targets (circular and elliptical metal pipe-type thin walls) were prepared to validate the developed measurement method and system. Not only inner and outer surface profiles but also thin-wall thickness profiles were measured simultaneously. Based on the output data, the circularity and wall thickness variation were calculated. The thickness profile results showed a good agreement with those obtained by a contact-type micrometer (1-µm resolution) at every 6-deg interval. The uncertainty budget for this measuring system with metrology tool path planning was estimated at approximately 1.4 µm.
Gas Labyrinth Seals: Improved Prediction of Leakage in Gas Labyrinth Seals Using an Updated Kinetic Energy Carry-Over Coefficient
Authors: Wu Tingcheng , Andrés Luis San 
Published: September 2020

Abstract
Though simple and fast, bulk-flow models (BFMs) for gas labyrinth seals (LSs) often predict the mass flow inaccurately. The BFM models rely on classical Neumann's equation model to characterize the flow through a labyrinth tooth. Presently, a computational fluid dynamics (CFD) analysis quantifies the effects of tip clearance (Cr) and operating conditions on the prediction of LS mass flow, and then derives an updated kinetic energy carry-over coefficient (μ1i) to improve the accuracy of Neumann's leakage equation. μ1i is a function of the seal tip clearance (Cr), the tooth pitch, and the total teeth number; but it does not depend on the seal supply or discharge pressures. The analysis selects a 14-teeth on stator LS (length/diameter = L/D = 0.29) with clearance Cr = (1/733)D and operating at nominal supply (Pin) and discharge (Pout) pressures equal to 73 bar and 51 bar, respectively, and at a rotor speed of 12 krpm (surface speed = 138 m/s). The CFD produces flow fields for LSs with a clearance varying from 80% to 200% of the nominal Cr, a gas supply pressure from 60 bar to 100 bar, and with various discharge pressures giving a pressure ratio (PR = Pout/Pin) ranging from 0.40 to 0.85. The numerous predictions deliver the mass flow as well as the bulk-flow velocities and cavity pressures within the seals. The kinetic energy carry-over coefficient (μ1i) increases with respect to the seal radial clearance (Cr). μ1i shows a parabolic correlation with PR; at first, μ1i increases with a rise in PR from a low value; and then, a further increase in PR leads to a decrease in μ1i. The coefficient μ1i is only sensitive to the PR and not to the magnitude of either the supply or discharge pressures. Lastly, for use with Neumann's leakage model, the CFD predictions produce an updated μ1i, a function of the seal geometry and the PR condition. Integration of the new μ1i correlation into a BFM code improves its accuracy to predict LS mass flow rate, a 19% difference against test data reduces to within 6%. A TOS LS tested by Ertas et al. (2012, Rotordynamic Force Coefficients for Three Types of Annular Gas Seals With Inlet Preswirl and High Differential Pressure Ratio,” ASME J. Eng. Gas Turbine Power, 134(4), p. 4250301) serves to further validate the accuracy of the modified leakage model.
The Environmental Impacts of Metal Powder Bed Additive Manufacturing
Authors: Liao Jiankan , Cooper Daniel R. 
Published: September 2020

AbstractAdditive manufacturing (AM) is widely recognized as a critical pillar of advanced manufacturing and is moving from the design shop to the factory floor. As AM processes become more popular, it is paramount that engineers and policymakers understand and then reduce their environmental impacts. This article structures the current work on the environmental impacts of metal powder bed processes: selective laser melting (SLM), direct metal laser sintering (DMLS), electron beam melting (EBM), and binder jetting (BJ). We review the potential benefits and pitfalls of AM in each phase of a part's lifecycle and in different application domains (e.g., remanufacturing and hybrid manufacturing). We highlight critical uncertainties and future research directions throughout. The environmental impacts of AM are sensitive to the specific production and use-phase context; however, several broad lessons can be extracted from the literature. Unlike in conventional manufacturing, powder bed production impacts are dominated by the generation of the direct energy (electricity) required to operate the AM machines. Combined with a more energy-intensive feedstock (metal powder), this means that powder bed production impacts are higher than in conventional manufacturing unless production volumes are very small (saving tool production impacts), and/or there are significant material savings through part light weighting or improved buy-to-fly ratios.