Computational Investigation of High Velocity Ballistic Impact Test on Kevlar 149

The Kevlar is an organic high crystalline fiber belonging to the aromatic polyamide family extensively used for its strength. Kevlar fiber posses high cut resistance and flame resistance, hence they have a wide range of application in ballistic and defense[2]. This paper investigates how K-149 behaves mechanically under sudden high velocity impact, it also shows which types of Kevlar grade hold the maximum impact stiffness capacity. In addition it also predicts the stress induced on the specimen at the time of impact. The ballistic impact object considered as 9mm standard size bullet used in short gun. The assumed velocity for these cases is 650m/s. The specimens K-149 & k-49 taken to be rectangle with the standard size 50 mm x 50 mm. The computational analysis done on Kevlar 49 & 149 and the results have been compared with the help of the pictorial representation of post processing abaqus results and the best ballistic material can be chosen. This paper also provided the recommended research data to fill the technology gap in defense material science.

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Kinematics of Nuclei of Sc Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600003890 ◽

1980 ◽

Vol 5 ◽

pp. 191-191

Author(s):

V. C. Rubin

Keyword(s):

High Velocity ◽

Stellar Population ◽

Hii Regions ◽

Emission Lines ◽

High Luminosity ◽

Rotation Curves ◽

Velocity Gradients ◽

Wide Range ◽

Central Regions ◽

Velocity Dispersions

For a sample of 21 Sc galaxies with a wide range of luminosities, of radii, and of masses, W. K. Ford and I have obtained spectra and determined rotation curves. By their kinematical behavior in their central regions, the Sc’s can be separated into two groups. Some galaxies, generally small and of low luminosity, have shallow central velocity gradients, reflecting their low central masses and densities. Other galaxies, most often large ones of high luminosity, have steep central velocity gradients. One reason this separation by central velocity gradients is of interest is because these galaxies exhibit other significant spectral differences which go hand-in-hand with the kinematical differences.The small, low luminosity galaxies show emission lines of Hα and [NII], with nuclear Ha sharp and stronger than [NII], and little or no stellar nuclear continuum, just as conventional HII regions. In contrast, the high luminosity galaxies show broad nuclear emission, with [NII] stronger than Ha. These galaxies have a strong red stellar continuum, arising from a red stellar population. The cause of the Hα[NII] intensity reversal in the nuclei of some galaxies remains unknown. However, the strong [NII] emission in generally high luminosity galaxies with massive nuclei, nuclei which show strong red continua, suggests that [Nil] intensity correlates with nuclear luminosity, and in turn with the density and velocity properties of the nuclear populations. We would expect high velocity dispersions and high bulge luminosities for galaxies with strong nuclear [NII] and steep central velocity gradients.

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Accuracy of a single rigid conical cuff with standard-size bladder coupled to an automatic oscillometric device over a wide range of arm circumferences

Hypertension Research ◽

10.1038/hr.2010.146 ◽

2010 ◽

Vol 33 (11) ◽

pp. 1186-1191 ◽

Cited By ~ 31

Author(s):

Elisa Bonso ◽

Francesca Saladini ◽

Ada Zanier ◽

Elisabetta Benetti ◽

Francesca Dorigatti ◽

...

Keyword(s):

Standard Size ◽

Oscillometric Device ◽

Wide Range

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A descriptive mode in art and the issue of a representation

Vestnik of Saint Petersburg State University of Culture ◽

10.30725/2619-0303-2020-3-11-17 ◽

2020 ◽

pp. 11-17

Author(s):

O. V. Bezzubova ◽

Keyword(s):

Visual Culture ◽

Art History ◽

American Art ◽

Pictorial Representation ◽

Research Approach ◽

Work Of Art ◽

Culture Studies ◽

Visual Culture Studies ◽

Wide Range ◽

New Research

The predominant for XX century art studies tradition was seriously reconsidered during the 1970– 1980s during the so called «new art history» development, when many received concepts were called into question. A notion of descriptiv e mode of painting proposed by an American art historian S. Alpers is of great interest in this context because it allows us to revise the homogeneous development of European art. While elaborating the concept of descriptive mode of painting, Alpers took under consideration a wide range of historical and cultural sources thus contributed to the new research approach nowadays known under the title of visual culture studies. It is not less important that she also focused on the issue of pictorial representation, which inquires the essence of the work of art.

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The effect of cell tilting on turbulent thermal convection in a rectangular cell

Journal of Fluid Mechanics ◽

10.1017/jfm.2014.655 ◽

2014 ◽

Vol 762 ◽

pp. 273-287 ◽

Cited By ~ 15

Author(s):

Shuang-Xi Guo ◽

Sheng-Qi Zhou ◽

Xian-Rong Cen ◽

Ling Qu ◽

Yuan-Zheng Lu ◽

...

Keyword(s):

High Velocity ◽

Large Scale ◽

Velocity Measurements ◽

Cell Width ◽

Rectangular Cell ◽

Aspect Ratios ◽

Wide Range ◽

Almost All ◽

Temperature And Velocity Fields ◽

Pronounced Reduction

AbstractIn this study the influence of cell tilting on flow dynamics and heat transport is explored experimentally within a rectangular cell (aspect ratios ${\it\Gamma}_{x}=1$ and ${\it\Gamma}_{y}=0.25$). The measurements are carried out over a wide range of tilt angles ($0\leqslant {\it\beta}\leqslant {\rm\pi}/2\ \text{rad}$) at a constant Prandtl number ($\mathit{Pr}\simeq 6.3$) and Rayleigh number ($\mathit{Ra}\simeq 4.42\times 10^{9}$). The velocity measurements reveal that the large-scale circulation (LSC) is sensitive to the symmetry of the system. In the level case, the high-velocity band of the LSC concentrates at about a quarter of the cell width from the boundary. As the cell is slightly tilted (${\it\beta}\simeq 0.04\ \text{rad}$), the position of the high-velocity band quickly moves towards the boundary. With increasing ${\it\beta}$, the LSC changes gradually from oblique ellipse-like to square-like, and other more complicated patterns. Oscillations have been found in the temperature and velocity fields for almost all ${\it\beta}$, and are strongest at around ${\it\beta}\simeq 0.48\ \text{rad}$. As ${\it\beta}$ increases, the Reynolds number ($\mathit{Re}$) initially also increases, until it reaches its maximum at the transition angle ${\it\beta}=0.15\ \text{rad}$, after which it gradually decreases. The cell tilting causes a pronounced reduction of the Nusselt number ($\mathit{Nu}$). As ${\it\beta}$ increases from 0 to 0.15, 1.05 and ${\rm\pi}/2\ \text{rad}$, the reduction of $\mathit{Nu}$ is approximately 1.4 %, 5 % and 18 %, respectively. Over the ranges of $0\leqslant {\it\beta}\leqslant 0.15\ \text{rad}$, $0.15\leqslant {\it\beta}\leqslant 1.05\ \text{rad}$ and $1.05\leqslant {\it\beta}\leqslant {\rm\pi}/2\ \text{rad}$, the decay slopes are $8.57\times 10^{-2}$, $3.27\times 10^{-2}$ and $0.24\ \text{rad}^{-1}$, respectively.

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The X-ray view of the Wolf-Rayet stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900202428 ◽

1995 ◽

Vol 163 ◽

pp. 429-437

Author(s):

A.M.T. Pollock

Keyword(s):

High Velocity ◽

X Ray ◽

Wide Range ◽

Colliding Winds

Ever since the earliest work, X-ray observations have been central in the chequered development of the study of interacting high-velocity winds in binaries. This review assesses how confidently the observations of Wolf-Rayet stars may be interpreted as the result of colliding winds, drawing attention to the wide range of X-ray luminosities even among the relatively bright binaries. Although the data do not generally conform to the simplest binary models, some suggestions are made to reconcile theory and observation.

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Spectroscopic diagnostics of T Tauri inner winds

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307009532 ◽

2007 ◽

Vol 3 (S243) ◽

pp. 171-182 ◽

Cited By ~ 1

Author(s):

Suzan Edwards

Keyword(s):

Velocity Component ◽

High Velocity ◽

T Tauri Stars ◽

Interaction Region ◽

Spectroscopic Diagnostics ◽

T Tauri ◽

Spectral Diagnostics ◽

Launch Site ◽

Wide Range

AbstractThe role of the star-disk interaction region in launching the high velocity component of accretion-driven outflows is examined. Spectroscopic indicators of high velocity inner winds have been recognized in T Tauri stars for decades, but identifying the wind launch site and the accompanying mass loss rates has remained elusive. A promising new diagnostic is He I λ10830, whose metastable lower level results in a powerful probe of the geometry of the outflowing gas in the interaction region. This, together with other atomic and molecular spectral diagnostics covering a wide range of excitation and ionization states, suggests that more than one launch site of the innermost wind is operational in most accreting stars.

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Velocity distribution function and correlations in a granular Poiseuille flow

Journal of Fluid Mechanics ◽

10.1017/s0022112010000200 ◽

2010 ◽

Vol 653 ◽

pp. 175-219 ◽

Cited By ~ 13

Author(s):

MEHEBOOB ALAM ◽

V. K. CHIKKADI

Keyword(s):

Shear Rate ◽

Poiseuille Flow ◽

High Velocity ◽

Elastic Limit ◽

Distribution Functions ◽

Transitional Flow ◽

Wall Region ◽

Surprising Result ◽

Granular Gas ◽

Wide Range

Probability distribution functions of fluctuation velocities (P(ux) and P(uy), where ux and uy are the fluctuation velocities in the x- and y-directions, respectively; the gravity is acting along the periodic x-direction and the flow is bounded by two walls parallel to the y-direction) and the density and the spatial velocity correlations are studied using event-driven simulations for an inelastic smooth hard disk system undergoing gravity-driven granular Poiseuille flow (GPF). It is shown that for GPF with smooth and/or perfectly rough walls the Maxwellian/Gaussian is the leading-order distribution over a wide range of densities in the quasi-elastic limit, which is a surprising result, especially for a dilute granular gas for which the Knudsen number belongs to the transitional flow regime. The signature of wall-roughness-induced dissipation mainly shows up in the P(ux) distribution in the form of a sharp peak for negative velocities in the near-wall region. Both P(ux) and P(uy) distributions become asymmetric with increasing dissipation at any density, and the emergence of density waves, which appear in the form of sinuous wave/slug at low-to-moderate values of mean density, makes these asymmetries stronger, especially in the presence of a slug. At high densities, the flow degenerates into a dense plug (where the density approaches its maximum limit and the shear rate is negligibly small) around the channel centreline and two shear layers (where the shear rate is high and the density is low) near the walls. The distribution functions within the shear layer follow the characteristics of those at moderate mean densities. Within the dense plug, the high-velocity tails of both P(ux) and P(uy) appear to undergo a transition from Gaussian in the quasi-elastic limit to power-law distributions at large inelasticity of particle collisions. For dense flows, it is shown that although the density correlations play a significant role in enhancing the velocity correlations when the collisions are sufficiently inelastic, they do not induce velocity correlations when the collisions are quasi-elastic for which the distribution functions are close to Gaussian. The combined effect of enhanced density and velocity correlations around the channel centreline with increasing inelastic dissipation seems to be responsible for the emergence of non-Gaussian high-velocity tails of distribution functions.

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Novel strategy for wide-range wind vector measurement using the hybrid CP/CTD heating mode and sequential measuring and correcting

PLoS ONE ◽

10.1371/journal.pone.0254256 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254256

Author(s):

Tian Wang ◽

Yunbo Shi ◽

Xiaoyu Yu ◽

Guangdong Lan ◽

Congning Liu

Keyword(s):

Wind Velocity ◽

Wind Direction ◽

High Velocity ◽

Measurement Instrument ◽

Wind Vector ◽

Velocity Range ◽

Vector Measurement ◽

Airflow Distribution ◽

Wide Range ◽

Novel Strategy

To improve the performance of wind sensors in the high velocity range, this paper proposes a wind measurement strategy for thermal wind velocity sensors that combines the constant power and constant temperature difference driving modes of the heating element. Based on the airflow distribution characteristics from fluid dynamics, sequential measurement and correction is proposed as a method of measuring wind direction. In addition, a wind velocity and direction measurement instrument was developed using the above-mentioned approaches. The test results showed that the proposed instrument can obtain large dynamic wind velocity measurements from 0 to 60 m/s. The wind velocity measurement accuracy was ±0.5 m/s in the common velocity range of 0–20 m/s and ±1 m/s in the high velocity range of 20–60 m/s. The wind direction accuracy was ±3° throughout the 360° range. The proposed approaches and instrument are not only practical but also capable of meeting the requirements of wide-range and large dynamic wind vector measurement applications.

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Laser-Driven High-Velocity Microparticle Launcher In Atmosphere And Under Vacuum

2019 15th Hypervelocity Impact Symposium ◽

10.1115/hvis2019-127 ◽

2019 ◽

Author(s):

David Veysset ◽

Yuchen Sun ◽

Steven E. Kooi ◽

Keith A. Nelson

Keyword(s):

Cold Spray ◽

High Velocity ◽

Optical Methods ◽

Metallic Coatings ◽

Spray Method ◽

Wide Range ◽

Gas Guns ◽

Projectile Impacts

Abstract The study of high-velocity microparticles is important to a wide range of both space and terrestrial applications. In space, high- and hyper-velocity micro-debris and micrometeorites, while also a subject of study, pose a threat to equipment and personnel integrity [1–4]. On earth, high-velocity microparticle impact can be, for instance, utilized for therapeutic purposes in the field of biolistics [5] or to build metallic coatings via the cold spray method [6]. While macroscale projectile impacts have been studied using well established experimental tools, such as light-gas guns, optical methods are gaining interest in the field of micro-particle impacts.

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