scholarly journals Target Design for XUV Probing of Radiative Shock Experiments

2020 ◽  
Vol 6 (1) ◽  
pp. 30-41
Author(s):  
U. Chaulagain ◽  
C. Stehlé ◽  
P. Barroso ◽  
M. Kozlova ◽  
J. Nejdl ◽  
...  
Keyword(s):  
Laboratory Astrophysics ◽  
The Novel ◽  
Radiative Shock ◽  
Radiative Shocks ◽  
Numerical Studies ◽  
Laser Facility ◽  
Post Shock ◽  
Technical Specifications ◽  
Novel Design ◽  
Target Design

Radiative shocks are strong shocks characterized by plasma at a high temperature emitting an important fraction of its energy as radiation. Radiative shocks are commonly found in many astrophysical systems and are templates of radiative hydrodynamic flows, which can be studied experimentally using high-power lasers. This is not only important in the context of laboratory astrophysics but also to benchmark numerical studies. We present details on the design of experiments on radiative shocks in xenon gas performed at the kJ scale PALS laser facility. It includes technical specifications for the tube targets design and numerical studies with the 1-D radiative hydrodynamics code MULTI. Emphasis is given to the technical feasibility of an XUV imaging diagnostic with a 21 nm (~58 eV) probing beam, which allows to probe simultaneously the post-shock and the precursor region ahead of the shock. The novel design of the target together with the improved X-ray optics and XUV source allow to show both the dense post-shock structure and the precursor of the radiative shock.

scholarly journals Analysis of microscopic properties of radiative shock experiments performed at the Orion laser facility

2018 ◽  
Vol 6 ◽  
Author(s):  
R. Rodríguez ◽  
G. Espinosa ◽  
J. M. Gil ◽  
F. Suzuki-Vidal ◽  
T. Clayson ◽  
...  
Keyword(s):  
Spectroscopic Properties ◽  
Radiation Hydrodynamics ◽  
Post Processing ◽  
Radiative Shock ◽  
Hydrodynamic Simulations ◽  
Shock Region ◽  
Laser Facility ◽  
Post Shock ◽  
Charge State Distributions ◽  
Thermodynamic Regime

In this work we have conducted a study on the radiative and spectroscopic properties of the radiative precursor and the post-shock region from experiments with radiative shocks in xenon performed at the Orion laser facility. The study is based on post-processing of radiation-hydrodynamics simulations of the experiment. In particular, we have analyzed the thermodynamic regime of the plasma, the charge state distributions, the monochromatic opacities and emissivities, and the specific intensities for plasma conditions of both regions. The study of the intensities is a useful tool to estimate ranges of electron temperatures present in the xenon plasma in these experiments and the analysis performed of the microscopic properties commented above helps to better understand the intensity spectra. Finally, a theoretical analysis of the possibility of the onset of isobaric thermal instabilities in the post-shock has been made, concluding that the instabilities obtained in the radiative-hydrodynamic simulations could be thermal ones due to strong radiative cooling.

scholarly journals Characterization of laser-driven Radiative shock of Astrophysical interests

2015 ◽  
Vol 11 (A29A) ◽  
Author(s):  
U. Chaulagain ◽  
C. Stehlé ◽  
J. Larour ◽  
M. Kozlová ◽  
F. Suzuki-Vidal ◽  
...  
Keyword(s):  
Shock Waves ◽  
Shock Structure ◽  
Experimental Results ◽  
Radiative Shock ◽  
X Ray ◽  
Laser Facility ◽  
Post Shock

AbstractWe highlight the recent experimental results on laser-driven radiative shock waves of astrophysical interests using kJ PALS laser facility. The generated shock is probed instantaneously by X-ray laser (λ = 21.2 nm) showing an unambiguous shock structure that includes both the post-shock and the precursor.

Experimental and numerical studies of radiative shocks

2006 ◽  
Vol 133 ◽  
pp. 1013-1017 ◽  
Author(s):  
C. Michaut ◽  
L. Boireau ◽  
T. Vinci ◽  
S. Bouquet ◽  
M. Koenig ◽  
...  
Keyword(s):  
Radiative Shocks ◽  
Numerical Studies

scholarly journals A laser experiment for studying radiative shocks in astrophysics

2002 ◽  
Vol 20 (2) ◽  
pp. 263-268 ◽  
Author(s):  
X. FLEURY ◽  
S. BOUQUET ◽  
C. STEHLÉ ◽  
M. KOENIG ◽  
D. BATANI ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Experimental Results ◽  
Laboratory Astrophysics ◽  
Laser Pulse Duration ◽  
Radiative Shocks ◽  
Self Similar ◽  
Laser Experiment ◽  
Similar Solutions

In this article, we present a laboratory astrophysics experiment on radiative shocks and its interpretation using simple modelization. The experiment is performed with a 100-J laser (pulse duration of about 0.5 ns) which irradiates a 1-mm3 xenon gas-filled cell. Descriptions of both the experiment and the associated diagnostics are given. The apparition of a radiation precursor in the unshocked material is evidenced from interferometry diagrams. A model including self-similar solutions and numerical ones is derived and fairly good agreements are obtained between the theoretical and the experimental results.

Calculation and Measurement of the Stiffness and Damping Coefficients for a Low Impedance Hydrodynamic Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. J. Goodwin ◽  
P. J. Ogrodnik ◽  
M. P. Roach ◽  
Y. Fang
Keyword(s):  
Experimental Data ◽  
Dynamic Stiffness ◽  
Perturbation Technique ◽  
The Novel ◽  
Oil Film ◽  
Hydrodynamic Bearing ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Novel Design

This paper describes a combined theoretical and experimental investigation of the eight oil film stiffness and damping coefficients for a novel low impedance hydrodynamic bearing. The novel design incorporates a recess in the bearing surface which is connected to a standard commercial gas bag accumulator; this arrangement reduces the oil film dynamic stiffness and leads to improved machine response and stability. A finite difference method was used to solve Reynolds equation and yield the pressure distribution in the bearing oil film. Integration of the pressure profile then enabled the fluid film forces to be evaluated. A perturbation technique was used to determine the dynamic pressure components, and hence to determine the eight oil film stiffness and damping coefficients. Experimental data was obtained from a laboratory test rig in which a test bearing, floating on a rotating shaft, was excited by a multi-frequency force signal. Measurements of the resulting relative movement between bearing and journal enabled the oil film coefficients to be measured. The results of the work show good agreement between theoretical and experimental data, and indicate that the oil film impedance of the novel design is considerably lower than that of a conventional bearing.

scholarly journals A novel flexible tool with rotary ultrasonic spindle for fine grinding of tungsten carbide

2018 ◽  
Vol 185 ◽  
pp. 00018
Author(s):  
Albert Wen-Jeng Hsue ◽  
Yi-Zhong Zheng
Keyword(s):  
Tungsten Carbide ◽  
The Novel ◽  
Machining Processes ◽  
Flexible Tool ◽  
Operational Conditions ◽  
Cnc Grinding ◽  
Grinding Conditions ◽  
Novel Design ◽  
Conventional Machining ◽  
Tungsten Steel

Tungsten carbide is a typical difficult-to-cut material by conventional machining processes. In this paper, a novel design of flexible abrasives tool combined with a rotary ultrasonic machining (RUM) spindle is conducted to reduce the labor force significantly. The newly designed flexibility of tool-tip is aimed at preventing overcutting from the CNC grinding. The grinding conditions with resulted surface morphology of the tungsten steel were investigated through Taguchi design of experiment and ANOVA analysis. The machining capability of the novel flexible tool is compared with conventional tools through specific grinding paths under proper operational conditions.

Why Do So Few Consumers Use Health Care Quality Report Cards? A Framework for Understanding the Limited Consumer Impact of Comparative Quality Information

2018 ◽  
Vol 76 (5) ◽  
pp. 515-537 ◽  
Author(s):  
Neeraj Bhandari ◽  
Dennis P. Scanlon ◽  
Yunfeng Shi ◽  
Rachel A. Smith
Keyword(s):  
Health Care Quality ◽  
Care Quality ◽  
Report Cards ◽  
Quality Information ◽  
The Novel ◽  
Cognitive Limitations ◽  
Provider Quality ◽  
The Media ◽  
New Generation ◽  
Novel Design

Despite growing investment in producing and releasing comparative provider quality information (CQI), consumer use of CQI has remained poor. We offer a framework to interpret and synthesize the existing literature’s diverse approaches to explaining the CQI’s low appeal for consumers. Our framework cautions CQI stakeholders against forming unrealistic expectations of pervasive consumer use and suggests that they focus their efforts more narrowly on consumers who may find CQI more salient for choosing providers. We review the consumer impact of stakeholder efforts to apply the burgeoning knowledge of consumers’ cognitive limitations to the design and dissemination of the new generation of report cards; we conclude that while it is too limited to draw firm conclusions, early evidence suggests consumers are responding to the novel design and dissemination strategies. We find that consumers continue to have difficulty accessing reliable report cards, while the media remains underused in the dissemination of report cards.

scholarly journals Translucent Answer Predictions in Multi-Hop Reading Comprehension

2020 ◽  
Vol 34 (05) ◽  
pp. 7700-7707
Author(s):  
G P Shrivatsa Bhargav ◽  
Michael Glass ◽  
Dinesh Garg ◽  
Shirish Shevade ◽  
Saswati Dana ◽  
...  
Keyword(s):  
Reading Comprehension ◽  
Question Answering ◽  
State Of The Art ◽  
Local Context ◽  
The Novel ◽  
Loose Coupling ◽  
Loosely Coupled ◽  
Neural Architecture ◽  
Coupled Networks ◽  
Novel Design

Research on the task of Reading Comprehension style Question Answering (RCQA) has gained momentum in recent years due to the emergence of human annotated datasets and associated leaderboards, for example CoQA, HotpotQA, SQuAD, TriviaQA, etc. While state-of-the-art has advanced considerably, there is still ample opportunity to advance it further on some important variants of the RCQA task. In this paper, we propose a novel deep neural architecture, called TAP (Translucent Answer Prediction), to identify answers and evidence (in the form of supporting facts) in an RCQA task requiring multi-hop reasoning. TAP comprises two loosely coupled networks – Local and Global Interaction eXtractor (LoGIX) and Answer Predictor (AP). LoGIX predicts supporting facts, whereas AP consumes these predicted supporting facts to predict the answer span. The novel design of LoGIX is inspired by two key design desiderata – local context and global interaction– that we identified by analyzing examples of multi-hop RCQA task. The loose coupling between LoGIX and the AP reveals the set of sentences used by the AP in predicting an answer. Therefore, answer predictions of TAP can be interpreted in a translucent manner. TAP offers state-of-the-art performance on the HotpotQA (Yang et al. 2018) dataset – an apt dataset for multi-hop RCQA task – as it occupies Rank-1 on its leaderboard (https://hotpotqa.github.io/) at the time of submission.

scholarly journals An Enhanced FPGA Based Asynchronous Microprocessor Design Using VIVADO and ISIM

2018 ◽  
Vol 7 (2) ◽  
pp. 199-208
Author(s):  
Archana Rani ◽  
Naresh Grover
Keyword(s):  
The Novel ◽  
Design And Implementation ◽  
Microprocessor Design ◽  
Novel Design

This paper deals with the novel design and implementation of asynchronous microprocessor by using HDL on Vivado tool wherein it has the capability of handling even I-Type, R-Type and Jump instructions with multiplier instruction packet. Moreover, it uses separate memory for instructions and data read-write that can be changed at any time. The complete design has been synthesized and simulated using Vivado. The complete design is targeted on Xilinx Virtex-7 FPGA. This paper more focuses on the use of Vivado Tool for advanced FPGA device. By using Vivado we get enhaced analysis result for better view of properly Route Placed design.

scholarly journals A Robotized Needle Insertion Device for Percutaneous Procedures

2005 ◽  
Author(s):  
Olivier Piccin ◽  
Pierre Renaud ◽  
Laurent Barbe´ ◽  
Bernard Bayle ◽  
Benjamin Maurin ◽  
...  
Keyword(s):  
Ct Scan ◽  
Medical Application ◽  
Needle Insertion ◽  
Computer Assisted ◽  
The Novel ◽  
Percutaneous Therapy ◽  
Percutaneous Procedures ◽  
Insertion Device ◽  
Haptic Control ◽  
Novel Design

In this paper, a new robotized needle insertion device is proposed for computer-assisted percutaneous therapy. The insertion device is integrated in a robotic system dedicated to gesture guidance in a Computed Tomography (CT) scan. The presented design fulfills the stringent requirements of such a medical application: compatibility with a CT-scan and haptic control by the practitioner are ensured as well as safety and sterilization. The novel design of the insertion device is first presented, outlining its main properties, before introducing preliminary experimental results.

Sign in / Sign up

Export Citation Format

Share Document