Thermal Insulative Performance of Single-Layer and Multiple-Layer Fabric Assemblies

2008 ◽  
pp. 421-421-17 ◽  
Author(s):  
WF Baitinger ◽  
L Konopasek
Keyword(s):  
Single Layer ◽  
Multiple Layer

scholarly journals Evaluation of the Effective Microstructure Parameter of the Microwave Emission Model of Layered Snowpack for Multiple-Layer Snow

2021 ◽  
Vol 13 (10) ◽  
pp. 2012
Author(s):  
Yue Yu ◽  
Jinmei Pan ◽  
Jiancheng Shi
Keyword(s):  
Process Model ◽  
Mean Squared Error ◽  
Weighted Average ◽  
Single Layer ◽  
Microwave Emission ◽  
Emission Model ◽  
Snow Layer ◽  
Optimal Method ◽  
Microstructure Parameter ◽  
Multiple Layer

Natural snow, one of the most important components of the cryosphere, is fundamentally a layered medium. In forward simulation and retrieval, a single-layer effective microstructure parameter is widely used to represent the emission of multiple-layer snowpacks. However, in most cases, this parameter is fitted instead of calculated based on a physical theory. The uncertainty under different frequencies, polarizations, and snow conditions is uncertain. In this study, we explored different methods to reduce the layered snow properties to a set of single-layer values that can reproduce the same brightness temperature (TB) signal. A validated microwave emission model of layered snowpack (MEMLS) was used as the modelling tool. Multiple-layer snow TB from the snow’s surface was compared with the bulk TB of single-layer snow. The methods were tested using snow profile samples from the locally validated and global snow process model simulations, which follow the natural snow’s characteristics. The results showed that there are two factors that play critical roles in the stability of the bulk TB error, the single-layer effective microstructure parameter, and the reflectivity at the air–snow and snow–soil boundaries. It is important to use the same boundary reflectivity as the multiple-layer snow case calculated using the snow density at the topmost and bottommost layers instead of the average density. Afterwards, a mass-weighted average snow microstructure parameter can be used to calculate the volume scattering coefficient at 10.65 to 23.8 GHz. At 36.5 and 89 GHz, the effective microstructure parameter needs to be retrieved based on the product of the snow layer transmissivity. For thick snow, a cut-off threshold of 1/e is suggested to be used to include only the surface layers within the microwave penetration depth. The optimal method provides a root mean squared error of bulk TB of less than 5 K at 10.65 to 36.5 GHz and less than 10 K at 89 GHz for snow depths up to 130 cm.

Characterization of Single- and Multiple-Layer Films by X-Ray Reflectometry

1991 ◽  
Vol 35 (A) ◽  
pp. 137-142 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
High Resolution ◽  
Single Layer ◽  
The Other ◽  
X Ray ◽  
Buried Interfaces ◽  
Multiple Layer ◽  
Reflectivity Data

AbstractPrecision X-ray reflectivity data were obtained with a high-resolution reflectometer equipped with a rotating anode X-ray source and Ge 220 channel monochromators (one placed before and the other after the specimen). The surfaces and buried interfaces of thin films were characterized by ieast-squares refinement of experimental data. Values of thickness, density, and/or roughness of Pt “single-layer” and Pt/Co based multiple-layer films were determined.

Study on Kinetics and Biocompatibility Evaluation of Multiple Polymer Layer with Biochemical Material Properties in Drug-Eluting Stent

2013 ◽  
Vol 644 ◽  
pp. 183-188
Author(s):  
Sergey Pavlinich ◽  
Xi Wei Liu ◽  
Hong Zhao ◽  
Zhen Li ◽  
Li Li
Keyword(s):  
Release Kinetics ◽  
Drug Carrier ◽  
Comparative Method ◽  
Single Layer ◽  
Drug Eluting Stent ◽  
Multiple Layer ◽  
Drug Eluting ◽  
Poly Ethylene ◽  
Surface Morphologies ◽  
Spraying Method

The Paclitaxel-eluting stents (PTX) with three-layered polymer coating were studied in this work. The PLGA (polylactic acid-co-glycolic acid) with 15 percent PEG (poly ethylene glycol) concentration in blend have been applied for preparing multiple layer drug carrier and fabricated on the surface of 316L stainless steel stents by ultrasonic atomization spraying method. The Paclitaxel was explored in doses: (~255μg) for single layer coated PTX (30 wt%), and (~275μg) for multiple layer coated PTX in accordance. Pre- and post-expansion surface morphologies of multiple layer stent were examined by scanning electron microscopy (SEM). The Paclitaxel release kinetics was studied by comparative method of release profiles of single layer PTX with 3-layered polymer coated PTX. The biocompatibility by hemolysis ratio and dynamic clotting time with platelet adhesion measurements also was investigated.

Penetration Behaviour of Steel Plates

2007 ◽  
Author(s):  
M. H. Abdelshafy ◽  
S. O. Oyadiji
Keyword(s):  
Single Layer ◽  
3D Models ◽  
Penetration Resistance ◽  
Residual Velocity ◽  
Steel Target ◽  
Multiple Layer ◽  
Damping Material ◽  
The Impact ◽  
Layer Steel ◽  
Penetration Behaviour

A finite element analysis using ABAQUS v6.6 has been performed to investigate the penetration behaviour of different target structures under the impact velocities of 1000 & 1200 m/s. The analysis has been performed to study the effect of the target configuration and the effect of introducing a damping material like rubber within the target structure on the penetration behaviour of these targets. Three dimensional (3D) models of targets consisting of various discrete one, two and three layers of hardened steel have been developed. The total thickness of each single or multiple layer steel target is 25 mm. These targets have been subjected to the impact of a projectile which was either blunt or had a hemispherical end and is made from a tungsten rod. Furthermore, 3D models consisting of layers of a damping material sandwiched between steel layers have also been developed and analysed. It is found that a purely steel target of multiple layers but of the same total thickness as a single layer steel target produced less residual velocity. This implies that the multiple layer steel targets produced more penetration resistance and, therefore, absorbed more of the impact energy than the single layer steel target. Similarly, multiple layer composite targets comprising layers of a damping material sandwiched between steel layers produced a greater penetration resistance and less residual velocity than a single layer steel target. However, the multiple layer composite targets only produced a slightly greater penetration resistance and less residual velocity than a multiple layer steel target.

Single-Layer Versus Multiple-Layer Closure of Leg Wounds After Long Saphenous Vein Harvest: A Prospective Randomized Trial

2005 ◽  
Vol 80 (6) ◽  
pp. 2162-2165 ◽  
Author(s):  
Muhammed Zafar ◽  
Anil John ◽  
Zahid Khan ◽  
Simon M. Allen ◽  
Adrian J. Marchbank ◽  
...  
Keyword(s):  
Randomized Trial ◽  
Saphenous Vein ◽  
Single Layer ◽  
Prospective Randomized Trial ◽  
Layer Versus ◽  
Long Saphenous Vein ◽  
Multiple Layer

Comparison of multiple-layer versus multiple-cavity microperforated panels for sound absorption at low frequency

2021 ◽  
Vol 69 (4) ◽  
pp. 341-350
Author(s):  
Pedro Cobo ◽  
Francisco Simón ◽  
Carlos Colina
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Single Layer ◽  
Helmholtz Resonator ◽  
Layer Versus ◽  
Low Frequencies ◽  
High Frequencies ◽  
Multiple Layer ◽  
Band Absorption ◽  
Microperforated Panels

Microperforated panels (MPPs) are recognized as suitable absorbers for noise control applications demanding special clean and health requirements.While it is relatively easy to design single-layer MPPs for sound absorption in one-to-two octave bands at medium-high frequencies, the performance for low frequencies (below 600 Hz) leads to a rather narrow-band absorption, similar to that of a Helmholtz resonator. However, multiple-layer MPPs can be designed as sound absorbers that yield low-frequency absorption in a wide frequency band. Recently, multiple-cavity perforated panels have been proposed to improve the performance of MPPs in the low-frequency range. In this article, the capability of multiple-layer and multiple-cavity MPPs to provide sound absorption at low frequencies is analyzed.

scholarly journals Development of Oxygen-Plasma-Surface-Treated UHMWPE Fabric Coated with a Mixture of SiC/Polyurethane for Protection against Puncture and Needle Threats

Fibers ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 46 ◽  
Author(s):  
Dariush Firouzi ◽  
Chan Y. Ching ◽  
Syed N. Rizvi ◽  
P. Ravi Selvaganapathy
Keyword(s):  
Oxygen Plasma ◽  
Single Layer ◽  
Areal Density ◽  
Hypodermic Needle ◽  
Resistance Force ◽  
Oxygen Plasma Treatment ◽  
Multiple Layer ◽  
Coated Fabric ◽  
Parametric Studies ◽  
Maximum Penetration

Although considerable research has been directed at developing materials for ballistic protection, considerably less has been conducted to address non-firearm threats. Even fewer studies have examined the incorporation of particle-laden elastomers with textiles for spike, knife, and needle protection. We report on a new composite consisting of ultra-high-molecular-weight polyethylene (UHMWPE) fabric impregnated with nanoparticle-loaded elastomer, specifically designed for spike- and needle-resistant garments. Failure analysis and parametric studies of particle-loading and layer-count were conducted using a mixture of SiC and polyurethane at 0, 30, and 50 wt.%. The maximum penetration resistance force of a single-layer of uncoated fabric increased up to 218–229% due to nanoparticle loading. Multiple-layer stacks of coated fabric show up to 57% and 346% improvement in spike puncture and hypodermic needle resistance, respectively, and yet were more flexible and 21–55% thinner than a multiple-layer stack of neat fabric (of comparable areal density). We show that oxygen-plasma-treatment of UHMWPE is critical to enable effective coating.

Microstructure and Current Transport Properties of YBa2Cu3O7-x/(Ba0.05, Sr0.95)TiO3 Multiple-Layer Thin Films

2003 ◽  
Vol 795 ◽  
Author(s):  
Y. Luo ◽  
R. A. Hughes ◽  
J. S. Preston ◽  
G. A. Botton
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electrical Properties ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Nanocomposite Films ◽  
Mismatch Strain ◽  
Multiple Layer ◽  
Transmission Electron

ABSTRACTYBa2Cu3O7-x (YBCO) films grown by pulsed laser deposition (PLD) on (100) LaAlO3 (LAO) substrates show a strong thickness dependence on the electrical properties. For example, for films in excess of 0.3 μm, the critical current density decreases with increasing thickness. In contrast, nano-composite films consisting of a series of multiple layers of YBa2Cu3O7-x and (Ba0.05, Sr0.95)TiO3 (BSTO) thin films having a total thickness of 5 μm show improved electrical properties. In order to understand this phenomenon, a detailed microstructural characterization has been undertaken. Transmission electron microscopy (TEM) observations show that cracks, stacking faults, c-║ crystals and secondary phase precipitates are present on the single-layer films, while a high-quality microstructure is observed for the nanocomposite multiple-layer films although defects at YBCO/BSTO interface are still present. In addition, nanocomposite films have a reduced surface roughness. In this complex microstructure, the YBCO/BSTO interfaces and the lattice mismatch strain play a crucial role in controlling the nature of the defects and stability of phases. In order to understand the role of the BSTO layer has on the microstructure, the interfacial mismatch strain and defects are analyzed by high-resolution transmission electron microscopy (HRTEM) in combination with the Moiré fringe technique.

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