Dynamic Countermeasure Fabrics for Post-Spaceflight Orthostatic Intolerance

2020 ◽  
Vol 91 (6) ◽  
pp. 525-531 ◽  
Author(s):  
Rachael M. Granberry ◽  
Kevin P. Eschen ◽  
Amy J. Ross ◽  
Julianna M. Abel ◽  
Bradley T. Holschuh
Keyword(s):  
Double Layer ◽  
High Performance ◽  
Orthostatic Intolerance ◽  
Dynamic Compression ◽  
Single Layer ◽  
Design Parameters ◽  
Layer System ◽  
Compression Garments ◽  
Air Supply ◽  
Low Profile

INTRODUCTION: Aerospace orthostatic intolerance garments (OIG) have historically been pneumatic (e.g., NASA’s antigravity suit), an approach that inhibits mobility and requires connection to an air supply. Elastic compression garments, an alternative technology, are difficult to don/doff and cannot be worn in a noncompressive state, resulting in discomfort and usability challenges. This research evaluates a novel technology—contractile shape memory alloy (SMA) knitted actuators—that can enable low-profile, dynamic compression for an aerospace OIG.METHODS: To characterize the functional capabilities of SMA knitted actuators, displacement control testing was conducted on 10 actuator samples with a range of geometric design parameters. Inactive (FI) and actuated forces (FA) were observed by repeatedly thermally cycling each sample at 0%, 15%, 30%, and 45% structural strain. Compression capabilities were approximated using medical compression hosiery standards and anthropometric data from a representative aerospace population (ANSUR 2012).RESULTS: Dynamic compression predictions reached 52 mmHg (single layer fabric) and 105 mmHg (double layer fabric) at the ankle. Low, inactive pressures (p < 20 mmHg) demonstrate that compression is controllable and can be dynamically increased upon actuation up to 33 mmHg in a single layer system and up to 67 mmHg in a double layer system.DISCUSSION: The results highlight the potential of SMA knitted actuators to enable low-profile, dynamic compression garments that can reach medically therapeutic pressures on an aerospace population to counteract OI symptoms. In addition to astronautic applications, this technology demonstrates widespread terrestrial medical and high-performance aircraft applicability.Granberry RM, Eschen KP, Ross AJ, Abel JM, Holschuh BT. Dynamic countermeasure fabrics for post-spaceflight orthostatic intolerance. Aerosp Med Hum Perform. 2020; 91(6):525–531.

scholarly journals Characteristics of Oceanic Warm Cloud Layers within Multilevel Cloud Systems Derived by Satellite Measurements

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 465 ◽  
Author(s):  
Yuhao Ding ◽  
Qi Liu ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Lower Layer ◽  
Single Layer ◽  
Distribution Patterns ◽  
Radar Data ◽  
Multilayered Structures ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

Low-level warm clouds are a major component in multilayered cloud systems and they are generally hidden from the top-down view of satellites with passive measurements. This study conducts an investigation on oceanic warm clouds embedded in multilayered structures by using spaceborne radar data with fine vertical resolution. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds, and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system they have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness of around 1 km, the cloudless gap reaches its maximum when exceeding 600 m. The cloudless gap decreases in thickness as the two cloud layers become even thinner or thicker.

Design and Implementation of QCA D-Flip-Flops and RAM Cell Using Majority Gates

2019 ◽  
Vol 28 (05) ◽  
pp. 1950079 ◽  
Author(s):  
Trailokya Nath Sasamal ◽  
Ashutosh Kumar Singh ◽  
Umesh Ghanekar
Keyword(s):  
Circuit Design ◽  
High Speed ◽  
High Performance ◽  
Single Layer ◽  
Memory Cell ◽  
Design Parameters ◽  
Flip Flop ◽  
Negative Edge ◽  
Wire Crossing ◽  
The Common

Quantum-dot cellular automata (QCA) is one of the promising technologies that enable nanoscale circuit design with high performance and low-power consumption features. As memory cell and flip-flops are rudimentary for most of the digital circuits, having a high speed, and a less complex memory cell is significantly important. This paper presents novel architecture of D flip-flops and memory cell using a recently proposed five-input majority gate in QCA technology and simulated by QCADesigner tool version 2.0.3. The simulation results show that the proposed D flip-flops and the memory cell are more superior to the existing designs by considering the common design parameters. The proposed RAM cell spreads over an area of 0.12[Formula: see text][Formula: see text]m2and delay of 1.5 clock cycles. The proposed level-triggered, positive/negative edge-triggered, and dual edge-triggered D flip-flop uses 14%, 33%, and 21% less area, whereas the latency is 40%, 27%, and 25% less when compared to the previous best design. In addition, all the proposed designs are implemented in a single layer QCA and do not require any single or multilayer wire crossing.

scholarly journals The Design and Development of Active Compression Garments for Orthostatic Intolerance

2017 ◽  
Author(s):  
Julia Duvall ◽  
Rachael Granberry ◽  
Lucy E. Dunne ◽  
Brad Holschuh ◽  
Christopher Johnson ◽  
...  
Keyword(s):  
Venous Return ◽  
Orthostatic Intolerance ◽  
Dynamic Control ◽  
The Body ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Compression Stockings ◽  
Design And Development ◽  
Compression Garments ◽  
Prototype Development ◽  
Low Profile

Current compression garments are often made from a spandex-type elastic material with static levels of compression and can become uncomfortable and difficult to don/doff [1]. This limits their usability, especially for unhealthy or aging populations. The only current alternative to elastic compression stockings are inflatable compression sleeves that are controllable, but highly immobile and must be tethered to an inflation source [2]. Neither design offers a solution that is simultaneously low profile, mobile, and controllable. Here we present the design and development of compression garments with embedded shape-changing materials that can produce controllable compression without the need for a bulky inflation system. This active materials approach enables dynamic control over the degree, timing and location of compression, and allows for graded, synchronized, pulsed, and peristaltic compression patterns, which provide the medical benefit of moving fluid in the body [2]. Such a design combines the best features of both elastic and inflatable compression garments: a slim, low-profile form factor that is easy to don/doff and provides dynamic control. Shape memory alloy (SMA) coil actuators, as described by Holschuh et al., [3] have the ability to apply compressive forces to the body when paired with passive textiles and wrapped circumferentially around the body. These actuators are engineered to contract when heated, creating controllable forces and displacements that are modulated through an applied current. SMA compression garments (SMA-CG) have important applications, from consumer uses to clinical interventions, including: augmenting venous return for conditions of orthostatic intolerance (e.g., postural orthostatic tachycardia syndrome (POTS)); cardiac rehabilitation in heart failure patients; lymphedema venous insufficiency; reducing deep vein thrombosis (DVT) risk; sports performance; and countermeasures for flight or space flight. While the potential uses for this technology are broad, the basic design is similar across many conditions. Key research areas include: 1) identifying and addressing design considerations relevant to prototype development of SMA-CG; 2) determining the compression thresholds needed to dynamically oppose orthostatic changes; and 3) evaluating the effectiveness of the prototypes for augmented venous return by synchronizing compression during cardiac diastole. Here, we focus on the first question: design of SMA-CG prototypes.

Oceanic warm cloud layers within multilevel cloud systems observed by satellite measurements

2020 ◽  
Author(s):  
Qi Liu ◽  
Yuhao Ding ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Radiative Forcing ◽  
Lower Layer ◽  
Numerical Models ◽  
Three Dimensional ◽  
Single Layer ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

&lt;p&gt;Low-level warm clouds are a major component in multilayered cloud systems and are generally hidden from the top-down view of satellites with passive measurements. By using spaceborne radar data with fine vertical resolution, this study conducts an investigation on oceanic warm clouds embedded in multilayered structures. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness around 1 km, the cloudless gap reaches its maximum exceeding 600 m. As the two cloud layers become even thinner or thicker, the cloudless gap decreases in thickness. It is believed that such knowledge on cloud overlapping is critical for fully understanding the distribution of warm clouds in three-dimensional space. The results derived in this study could help validating cloud results of numerical models, which are indeed three-dimensional in nature. They could also be used to improve the estimation of cloud radiative forcing, since it is affected by cloud occurrences and especially their vertical structures. It should be pointed out that solid explanations for the above cloud features cannot be presented by only using these satellite data themselves.&amp;#160;&lt;/p&gt;

scholarly journals Durability and Performance of Ferrocement Infill Wall Panel

2019 ◽  
Vol 5 (6) ◽  
pp. 1205-1213
Author(s):  
Muhammad Harunur Rashid ◽  
Zahangir Alam ◽  
Firoz Mahmud ◽  
M S Anita
Keyword(s):  
Double Layer ◽  
High Performance ◽  
Steel Wire ◽  
Small Diameter ◽  
Single Layer ◽  
Wire Mesh ◽  
Temperature Cycle ◽  
Infill Wall ◽  
Strength Performance ◽  
Layer Sample

Ferrocement is composed of cement mortar reinforced with small diameter closely spaced steel wire mesh to form a thin section conforming high performance of serviceability. The present study investigates the performance of ferrocement panels focused on the mechanical properties, water absorption and durability. A series of specimens were cast with single and double mesh layers. Flexural performance was carried out following sixty days in temperature cycle and in corrosion cell. These results was compared with the controlled sample. The test results shows that the flexural strength performance was reduced by 52% and 35% for single and double layer wire mesh samples respectively  followed by corrosion environment. First crack load also changed after completion of sixty temperature cycles. This load is 27.3%, 42.3% and 31.8% of failure load for controlled sample, sample in room air after every temperature cycle and samples in room air following quenching after every temperature cycle respectively for single mesh layer sample, and for double mesh layer sample these values are 38.9%, 30.1% and 17.7%. Early first crack is found for the samples following quenching and cooled in room air; however, both types of samples are in low absorption level. This data represents that double layer mesh specimen exhibits better when compared to single layer mesh specimen in strength and corrosion parameters.

Ultra-Slim Packages

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001477-001506
Author(s):  
Bernd K. Appelt
Keyword(s):  
Cross Section ◽  
Double Layer ◽  
Thermal Performance ◽  
Cycle Time ◽  
Single Layer ◽  
Reliability Data ◽  
Number Of Layers ◽  
Low Profile

What does thin or ultra-slim packaging mean? That of course depends on the particular cross-section of the substrate e.g. single layer vs. double layer vs. coreless or embedded component substrate, etc. The thinnest prepreg based substrate and concomitant package is a single layer substrate termed a-S3 ™ and can be as thin as 90 μ and 400 μ, respectively, with the appropriate mold cap. The manufacturing concept for a-S3 has inspired a new manufacturing concept for thin prepreg based coreless substrates with any number of layers. Layers two through five have been demonstrated successfully. The practical layer count is limited only by yield and cycle time. The same concept has been extended also to embedding active die as well as passives, a-EASI™. The total package height here is governed by the thickness of the embedded elements. The simplest embedded substrate is a two layer substrate with a MOSFET die. The advantage is a very low profile power package with excellent electrical and thermal performance. The interconnections to the die/passives are formed by plated laser vias as is common practice. Process flows and concepts will be introduced here. Thin substrates do pose many challenges during substrate manufacturing as well as during assembly. Some of the handling concepts will be elucidated. Sample pictures will be shown to demonstrate successful builds and some reliability data will be presented as well.

Design of Efficient Inductive Power Link with Small Size Planar Spiral Coil Receiver for Medical Applications

2020 ◽  
Vol 38 (2A) ◽  
pp. 199-210
Author(s):  
Muammer M. Omran ◽  
Ahmed S. Ezzulddin ◽  
Saad Mutashar
Keyword(s):  
Double Layer ◽  
Biological Tissue ◽  
Single Layer ◽  
Operating Frequency ◽  
Design Parameters ◽  
Medical Applications ◽  
Spiral Coil ◽  
Layer Technique ◽  
Link Efficiency ◽  
Comparative Survey

The efficiency of a WPT system greatly depends on both the geometry and operating frequency of the transmitting and receiving structures. Genetic optimizations algorithms are presented to prepare the proposed design parameters using MATLAB to optimize the link efficiency. Single and double layer PSCs are optimally designed with minimal proximity losses effect. In this paper, we used the benefit of a double layer technique to miniaturize the receiver PCS size. The proposed single layer (10×10) mm2 and double layer (8×8) mm2 PSCs are validated and simulated using HFSS 15.03 software at a frequency of 13.56MHz in both cases of the air, and human biological skin tissue as intermediate material between the transmitter and receiver PSCs. The calculated and simulated results of both proposed receiver PSCs are compared for both cases of intermediate materials for their efficiency behaviors. The results show that in the case of biological tissue, the deterioration in PTE using 8mm double layer receiver is only 6.5 % (PTE =70.96%), which is less than 13.5 % (PTE=68.6%) using single layer 10mm receiver. A comparative survey has been done for similar works of different authors in the last decade. In comparison with other works, the proposed double layer (8×8) mm2 PSCs is smaller in size and more efficient for use in the IMDs.

scholarly journals Investigation of a Multiple Impeller Design for a High Performance Air-Cooled Heat Sink

2010 ◽  
Author(s):  
Wayne L. Staats ◽  
Teresa B. Peters ◽  
Jon M. Allison ◽  
Matthew McCarthy ◽  
Evelyn N. Wang ◽  
...  
Keyword(s):  
Heat Sink ◽  
High Performance ◽  
Inflation Rate ◽  
Air Flow ◽  
Single Layer ◽  
Circuit Model ◽  
Flow Modeling ◽  
Hot Wire ◽  
Layer System ◽  
Flow Circuit

A high-performance air-cooled heat sink that incorporates a novel heat pipe with multiple parallel condenser layers and interdigitated blower impellers is presented. A flow circuit model was developed in order to predict the air flow performance of a 15-layer impeller system using experimental measurements from a single layer. A 15-layer impeller system was constructed to validate the flow circuit model. The performance of the multi-layer system was investigated by using a hot wire anemometer to compare flow between layers and by measuring the inflation rate of a bag enclosing the air outlets. This work addresses important issues that allow the extension of the air flow modeling and experimental results from a single impeller design to a multilayer stack of impellers operating in parallel and sharing a common inlet.

Single-chorded Plane Space Trusses

1985 ◽  
Vol 1 (2) ◽  
pp. 69-74 ◽  
Author(s):  
L. C. Schmidt
Keyword(s):  
Double Layer ◽  
Single Layer ◽  
Transverse Load ◽  
Layer System ◽  
Torsional Mode ◽  
Web System ◽  
Plane Space ◽  
Space Trusses ◽  
The Web ◽  
Web Systems

A discussion is presented of the mechanics of the plate-like behaviour of certain space trusses that possess a single layer of chords. The web systems are formed out of the chord plane, and consideration is given to web systems that are placed on one or both sides of the chord plane. It is recognized that a torsional mode of behaviour is utilized for the double-layer web system for carrying transverse load. A combination of flexural and torsional modes is utilized for the single-layer system.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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