bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of red blood cell transfusion on global oxygenation in anemic critically ill patients
Authors: Themelin Nicolas , Biston Patrick , Massart Jacqueline , Lelubre Christophe , Piagnerelli Michaël 
Published: February 2021

AbstractBackgroundConsensus for transfusion in intensive care unit (ICU) patients recommends a restrictive strategy, based on a hemoglobin (Hb) concentration of 7 g/dL. Red blood cell (RBC) transfusion is used to prevent tissue hypoxia by improving oxygen transport (DO2) and therefore oxygen consumption (VO2). We studied the effects of RBC transfusion on systemic oxygenation parameters reflecting systemic oxygen extraction (EO2 = DO2/VO2): S(c)vO2, lactate level, venous‐to‐arterial carbon dioxide difference (Pv‐aCO2), and cardiac index/EO2 (CI/EO2) and evaluated their usefulness in guiding transfusion decisions in ICU patients.Study Design and MethodsProspectively, all adult patients transfused were included except those with active bleeding or without a jugular or subclavian catheter. We measured O2 parameters before and after transfusion. Patients were a priori grouped according to their initial S(c)vO2 (< or ≥70%), treatment with vasopressors, cardiac function, and septic status.ResultsA total of 62 patients received 105 RBC transfusions. For all, mean arterial pressure (77 [69‐88] to 81 [73‐91] mm Hg), Hb concentration (7.4 [7.0‐7.8] to 8.4 [7.7‐8.9] g/dL) and S(c)vO2 (65% [59%‐73%] to 69% [62%‐75%]) increased after transfusion (all P < .001). S(c)vO2 improved after transfusion only when initial S(c)vO2 was less than 70% (62% [56%‐65%] to 66% [61%‐71%]; P < .001). In this group, Pv‐aCO2, lactate concentrations, and CI/EO2 did not change after transfusion. Cardiac function, sepsis, or vasopressor therapy did not affect these results.ConclusionsAmong systemic O2 parameters, only a S(c)vO2 < 70% in anemic ICU patients improves after transfusion. As S(c)vO2 can reflect a DO2/VO2 imbalance, it could be helpful when combined with the Hb concentration to decide whether to transfuse. However, the benefit on outcome should be further studied.
Preliminary study of the stability of dexamethasone when added to commercial veterinary ear cleaners over a 90 day period
Authors: Emery Carolyn B. , Outerbridge Catherine A. , Knych Heather K. , Lam Andrea T.H. , Gomez‐Vazquez Jose P. , White Stephen D. 
Published: February 2021

BackgroundTopical corticosteroids are commonly used in the management of allergic otitis externa to diminish inflammation. A common strategy is to make compounded solutions of dexamethasone in ear cleaner.Hypothesis/ObjectivesThe objective of this study was to determine the stability of dexamethasone when added to four commercial ear cleaners (ec): designated ecA, ecB, ecC and ecD.Methods and MaterialsTwo concentrations (0.1 and 0.25 mg/mL) of dexamethasone were formulated for each cleaner solution from a 2 mg/mL solution and stored in the original manufacturers’ bottles at two temperatures: room (22 ˚C) and refrigerated (4 ˚C). Samples were evaluated in triplicate, using liquid chromatography‐tandem mass spectrometry at 10 time points over 90 days. The mean and standard deviation were calculated for each time point.ResultsA solution was considered stable if the dexamethasone value remained >90% of the target concentration. All dexamethasone solution values were stable to 90 days, except two solutions for ecA; the 0.25 mg/mL dexamethasone concentration was only stable to 14 (4 ˚C) and 21 days (22 ˚C).Conclusions and clinical importanceThese results provide preliminary evidence in support of pharmaceutical stability data for dexamethasone when included in the above compounded solutions at the noted concentrations and temperatures.
A survey of laboratory biosafety and protective measures in blood transfusion departments during the COVID‐19 pandemic
Authors: Liu Haiting , Liu Leping , Zhang Junhua , Shang Xueling , Chen Sai , Li Xisheng , Gui Rong , Huang Rong 
Published: February 2021

AbstractBackground and objectivesThousands of healthcare workers (HCWs) have been infected with 2019 novel coronavirus pneumonia (COVID‐19) during the COVID‐19 pandemic. Laboratory personnel in blood transfusion departments may be infected with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) if laboratory biosafety protection is insufficient. Therefore, we investigated the current situation of laboratory biosafety protection in blood transfusion departments to determine how to improve the safety of laboratory processes.Materials and methodsAn online survey was conducted in blood transfusion departments from 1st to 6th May 2020 in China. A total of 653 individuals completed the questionnaire. The questionnaire was designed with reference to COVID‐19 laboratory biosafety summarized in Annex II. All responses were summarized using only descriptive statistics and expressed as frequencies and ratios [n (%)].ResultsMost participants were concerned about COVID‐19. Some participants had inadequate knowledge of COVID‐19. Two participants stated that there were laboratory personnel infected with SARS‐CoV‐2 in their departments. A total of 31 (4.7%) participants did not receive any safety and security training. In terms of laboratory biosafety protection practices, the major challenges were suboptimal laboratory safety practices and insufficient laboratory conditions.ConclusionThe major deficiencies were insufficient security and safety training, and a lack of personal protective equipment, automatic cap removal centrifuges and biosafety cabinets. Consequently, we should enhance the security and safety training of laboratory personnel to improve their laboratory biosafety protection practices and ensure that laboratory conditions are sufficient to improve the safety of laboratory processes.
A Three-Dimensional Tube Bundle Model Analysis for Leakage Flow Characteristics of Variable Bristle Diameter Brush Seals With Bristle Pack Stratification
Authors: Ma Dengqian , Li Zhigang , Li Jun 
Published: February 2021

Abstract
The leakage flow characteristics of the variable bristle diameter (VBD) brush seals are numerically investigated using the three-dimensional (3D) tube bundle model with consideration of bristle pack stratification. The discretization of the computational domain applies the multiblock structured mesh, which ensures that there is no need to set interfaces between the fluid domains of the bristle pack and the cavities to eliminate interpolation errors. The bristle pack stratification is achieved by using mesh motion technique from the point of cause-effect. The effects of pressure ratio (Rp=1.5, 2.5, 3.5), axial rows of bristles (Nx=9–21), sealing clearance (c=0, 0.1 mm), bristle pack arrangements, and bristles gapping (gi=0, 0.005, 0.010, 0.015 mm) on the leakage flow characteristics and aerodynamic forces are conducted. The recorded leakage flow of the 3D tube bundle model is multiplied by circumferential loop number (Ncl) to determine total leakage flow rate of the brush seal. The numerical results agreed well with the experimental data, which verifies the reliability of the numerical method. The numerical results indicate that the leakage flow rate increases linearly with the pressure ratio. The increase of Nx has a distinctly different effect on the relative rate of leakage flow for the contacting and clearance brush seals. The use of large diameter bristles weakens the sealing performance of the brush seals, particularly in the rear region. Bristle pack stratification can improve the sealing performance of the brush seals. The large diameter bristles increase the porosity and reduce the flow resistance coefficients. On the contrary, the bristle pack stratification decreases the porosity and rises the flow resistance coefficients in the rear region. The results of this article indicate when designing VBD brush seals, the effects of bristle diameter and bristle density on the sealing performance and pressure loading capacity of the brush seals should be fully considered.
Volumetric Velocimetry Measurements of Purge–Mainstream Interaction in a One-Stage Turbine
Authors: Carvalho Figueiredo A. J. , Schreiner B. D. J. , Mesny A. W. , Pountney O. J. , Scobie J. A. , Li Y. S. , Cleaver D. J. , Sangan C. M. 
Published: February 2021

Abstract
Air-cooled gas turbines employ bleed air from the compressor to cool vulnerable components in the turbine. The cooling flow, commonly known as purge air, is introduced at low radius, before exiting through the rim-seal at the periphery of the turbine discs. The purge flow interacts with the mainstream gas path, creating an unsteady and complex flowfield. Of particular interest to the designer is the effect of purge on the secondary-flow structures within the blade passage, the extent of which directly affects the aerodynamic loss in the stage. This paper presents a combined experimental and computational fluid dynamics (CFD) investigation into the effect of purge flow on the secondary flows in the blade passage of an optically accessible one-stage turbine rig. The experimental campaign was conducted using volumetric velocimetry (VV) measurements to assess the three-dimensional inter-blade velocity field; the complementary CFD campaign was carried out using unsteady Reynolds-averaged Navier–Stokes (URANS) computations. The implementation of VV within a rotating environment is a world first and offers an unparalleled level of experimental detail. The baseline flow-field, in the absence of purge flow, demonstrated a classical secondary flow-field: the rollup of a horseshoe vortex, with subsequent downstream convection of a pressure-side and suction-side leg, the former transitioning in to the passage vortex. The introduction of purge, at 1.7% of the mainstream flowrate, was shown to modify the secondary flow-field by enhancing the passage vortex, in both strength and span-wise migration. The computational predictions were in agreement with the enhancement revealed by the experiments.
Adaptive Kriging Method for Uncertainty Quantification of the Photoelectron Sheath and Dust Levitation on the Lunar Surface
Authors: Wei Xinpeng , Zhao Jianxun , He Xiaoming , Hu Zhen , Du Xiaoping , Han Daoru 
Published: February 2021

Abstract
This paper presents an adaptive Kriging based method to perform uncertainty quantification (UQ) of the photoelectron sheath and dust levitation on the lunar surface. The objective of this study is to identify the upper and lower bounds of the electric potential and that of dust levitation height, given the intervals of model parameters in the one-dimensional (1D) photoelectron sheath model. To improve the calculation efficiency, we employ the widely used adaptive Kriging method (AKM). A task-oriented learning function and a stopping criterion are developed to train the Kriging model and customize the AKM. Experiment analysis shows that the proposed AKM is both accurate and efficient.
Errors Characterization of a RANS Simulation
Authors: Pasinato Hugo D. , Krumrick Ezequiel A. 
Published: February 2021

Abstract
This research uses data from direct numerical simulation (DNS) to characterize the different errors associated with a Reynolds-averaged Navier–Stokes (RANS) simulation. The statistics from DNS (Reynolds stresses, kinetic energy of turbulence, κ, and dissipation of turbulence, ε), are fed into a RANS simulation with the same Reynolds number, geometry, and numerical code used for DNS. Three integral metrics error based on the mean velocity, the moduli of the mean rate-of-strain tensor, and the wall shear stress are used to characterize the errors associated with the RANS technique, with the RANS model, and with the linear eddy viscosity model (LEVM). For developed and perturbed flow, it is found that the mean velocity of the RANS simulations with the DNS statistics is almost the same as the mean velocity from DNS data. This procedure enables the study of the relative importance of the different Reynolds stresses in a particular flow. It is shown that for the bounded perturbed turbulent flows studied here, almost all the necessary effects of turbulence are contained in the Reynolds shear stress.
New Hammerstein Modeling and Analysis for Controlling Melt Pool Width in Powder Bed Fusion Additive Manufacturing
Authors: Wang Dan , Zhao Xinyu , Chen Xu 
Published: February 2021

Abstract
Despite the advantages and emerging applications, broader adoption of powder bed fusion (PBF) additive manufacturing is challenged by insufficient reliability and in-process variations. Finite element modeling and control-oriented modeling have been shown to be effective for predicting and engineering part qualities in PBF. This paper first builds a finite element model (FEM) of the thermal fields to look into the convoluted thermal interactions during the PBF process. Using the FEM data, we identify a novel surrogate system model from the laser power to the melt pool width. Linking a linear model with a memoryless nonlinear submodel, we develop a physics-based Hammerstein model that captures the complex spatiotemporal thermomechanical dynamics. We verify the accuracy of the Hammerstein model using the FEM and prove that the linearized model is only a representation of the Hammerstein model around the equilibrium point. Along the way, we conduct the stability and robustness analyses and formalize the Hammerstein model to facilitate the subsequent control designs.
Fluid Dynamics of a Bistable Diverter Under Ultrasonic Excitation—Part I: Performance Characteristic
Authors: Mair Michael , Bacic Marko 
Published: February 2021

Abstract
This paper investigates an ultrasonically driven bistable fluidic diverter at inlet nozzle Mach numbers of up to Mn = 0.3 and operating pressure ratios of up to Pr = 1.1. Part I examines the switching characteristics with respect to nondimensional parameters of excitation amplitude, frequency, required energy, switching time and inlet total pressure. It is shown that to promote switching at turbulent jet Mach numbers of up to Mn = 0.3 it is necessary to excite a jet preferred mode of St = 0.45 which differs from previously reported laminar jet operation of the similar device. For the reference case the switching time amounts to 1.2 ms suggesting oscillation frequencies of up to 500 Hz. Part II is a combined experimental and numerical study that examines the triggered instability modes in the free shear layer using large eddy simulations (LES) and visualizes the flow field using Particle Image Velocimetry (PIV).
Numerical Modeling of Initial Stress Stiffening Effect on the Dynamic Behavior of Axisymmetric Shells
Authors: Ben-Youssef Yacine , Kerboua Youcef , Lakis Aouni A. 
Published: February 2021

AbstractThis paper presents a numerical model to simulate the initial stress stiffening effect, induced by radial pressure and/or axial load on the dynamic behavior of axisymmetric shells. This effect is particularly important for thin shells since their bending stiffness is very small compared to membrane stiffness. The theoretical formulation is based on a combination of the finite element method and classical shell theory. For a perfect geometrical consistency, two semi-analytical finite elements, conical and cylindrical, are used to model axisymmetric shells. The displacement functions are derived from exact solutions of Sanders' shell equilibrium equations. The results obtained using this approach are remarkably accurate. The potential energy is calculated to estimate the initial stiffening effect using direct membrane forces per unit width and rotations about the orthogonal axes. The final stiffness matrix of each finite element is composed of the regular stiffness matrix and the added stiffness matrix generated by membrane loads. The frequencies of vibration are compared with those obtained in other experimental and theoretical research works and very good agreement is observed.
Stability Region-Based Analysis of Walking and Push Recovery Control
Authors: Peng William Z. , Song Hyunjong , Kim Joo H. 
Published: February 2021

Abstract
To achieve walking and push recovery successfully, a biped robot must be able to determine if it can maintain its current contact configuration or transition into another one without falling. In this study, the ability of a humanoid robot to maintain single support (SS) or double support (DS) contact and to achieve a step are represented by balanced and steppable regions, respectively, as proposed partitions of an augmented center-of-mass-state space. These regions are constructed with an optimization method that incorporates full-order system dynamics, system properties such as kinematic and actuation limits, and contact interactions with the environment in the two-dimensional sagittal plane. The SS balanced, DS balanced, and steppable regions are obtained for both experimental and simulated walking trajectories of the robot with and without the swing foot velocity constraint to evaluate the contribution of the swing leg momentum. A comparative analysis against one-step capturability, the ability of a biped to come to a stop after one step, demonstrates that the computed steppable region significantly exceeds the one-step capturability of an equivalent reduced-order model. The use of balanced regions to characterize the full balance capability criteria of the system and benchmark controllers is demonstrated with three push recovery controllers. The implemented hip–knee–ankle controller resulted in improved stabilization with respect to decreased foot tipping and time required to balance, relative to an existing hip–ankle controller and a gyro balance feedback controller.
A New Extensible Continuum Manipulator Using Flexible Parallel Mechanism and Rigid Motion Transmission
Authors: Liu Yujiong , Ben-Tzvi Pinhas 
Published: February 2021

Abstract
An extensible continuum manipulator (ECM) has specific advantages over its nonextensible counterparts. For instance, in certain applications, such as minimally invasive surgery or pipe inspection, the base motion might be limited or disallowed. The additional extensibility provides the robot with more dexterous manipulation and a larger workspace. Existing continuum robot designs achieve extensibility mainly through artificial muscle/pneumatic, extensible backbone, concentric tube, and base extension, etc. This article proposes a new way to achieve this additional motion degree-of-freedom by taking advantage of the rigid coupling hybrid mechanism concept and a flexible parallel mechanism. More specifically, a rack and pinion set is used to transmit the motion of the i-th subsegment to drive the (i+1)-th subsegment. A six-chain flexible parallel mechanism is used to generate the desired spatial bending and one extension mobility for each subsegment. This way, the new manipulator can achieve tail-like spatial bending and worm-like extension at the same time. Simplified kinematic analyses are conducted to estimate the workspace and the motion nonuniformity. A proof-of-concept prototype was integrated to verify the mechanism’s mobility and to evaluate the kinematic model accuracy. The results show that the proposed mechanism achieved the desired mobilities with a maximum extension ratio of 32.2% and a maximum bending angle of 80 deg.
Design and Virtual Prototyping of Human-Worn Manipulation Devices
Authors: Song Peng , Krovi Venkat , Kumar Vijay , Mahoney Richard 
Published: February 2021

Abstract
This paper presents a novel class of human-worn manipulation aids for people with disabilities, and a paradigm for the cost-effective design and manufacture of such devices. These manipulation aids are passive multi-link articulated devices that are physically connected to and controlled by a human user. This physical connection enables proprioceptive feedback control of the end effector. Performance can be enhanced by task and user customization of such devices prior to manufacture. As illustrative examples, we consider two case studies of the design and prototyping of customized manipulation aids for quadriplegics. We explore the use of the virtual prototyping and interactive simulation tools by the designer to customize the designs, virtually analyze the user-product interactions and progressively refine these designed aids. This process is aided by a unified design environment that integrates such support tools as automated data acquisition and measurement, mechanism synthesis and optimization, creation of customized synthetic models of the human user, and the user-based refinement of the product performance.
Development of a Feature Based Design System Using Virtual Reality
Authors: Summers Joshua D. , Butler Alley C. , Kuo Eddy 
Published: February 2021

Abstract
Virtual reality systems have been developed over the last few years to provide real time, immersive, three dimensional rendering. There have been efforts to utilize virtual reality and other similar approaches for design (Jones, 1996); however, limited information has been placed in the open literature describing the development of systems used specifically for the design of complex products, like naval vessels. As added motivation, features have been widely accepted as a useful paradigm for design purposes, but experience with feature based design in a virtual reality environment has also been limited. With these issues in mind, this paper was written to describe an ongoing research project that focuses on the demonstration of feature based design in a virtual reality environment for submarine design. To support this development, progress to date using the GROTTO, a CAVE like system, at the Naval Research Laboratory is reported. A “spin-off” of the research to web based collaboration is reported, an outline of projected system architecture is provided, and conclusions are drawn regarding the development of the virtual system.
Development of a Haptically Enabled Dis/Re-Assembly Simulation Environment
Authors: McDermott Scott D. , Bras Bert 
Published: February 2021

Abstract
Typical CAD environments constrain the user to one sense, sight, and two dimensions, the table upon which the mouse rests. The introduction of a haptic interface into the CAD environment allows users to incorporate both a third dimension and a second sense, that of touch, into their work. We are currently developing HIDRA (Haptic Integrated Dis/Re-assembly Analysis), an application that integrates haptic feedback into a (dis)assembly simulation environment. In this paper, we present the basic computer architecture of the application, including its interface with commercial CAD systems. We also explain some of application constraints unique to haptic simulation and the methods employed to help meet these constraints. Finally, we identify some available avenues for future work.
Wearable Computers and Augmented Reality in an Industrial Application
Authors: Santos Luiz M. A. 
Published: February 2021

Abstract
In the modern industrial scenario, the technological assets of new working methods and machinery in factory plants grow rapidly. Nevertheless, a reverse situation occurs in terms of availability of trained personnel within the subject area. Moreover, even the most experienced technician is faced with a continual need to update his/her skills. In respect to the training activities, more realism and a greater effectiveness could be achieved if the trainee could learn a new technology directly in the real working place. In this paper, considerations are presented for the use of an innovative hardware and Augmented Reality as platform components for the learning material to this training scenario. Both components are described with emphasis on their suitability to the target activity. The proposed platform encompasses a body-worn and wireless-networked computer, and software with specific features to assist the computer user in his/her task by enriching the content of the application environment. The software component, which addresses the application goals and required adaptations to the platform, is presented.