scholarly journals Design and Experimental Study of Space Continuous Robots Applied to Space Non-Cooperative Target Capture

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 536
Author(s):  
Yuwang Liu ◽  
Dongqi Wang ◽  
Yongchao Zhang ◽  
Zhongqiu Yuan ◽  
Jinguo Liu ◽  
...  
Keyword(s):  
Space Environment ◽  
Target Capture ◽  
Wide Range ◽  
Constrained Environments ◽  
In Series ◽  
Vacuum Radiation ◽  
Space Environments ◽  
Electrical Components ◽  
Scissor Mechanism ◽  
Robot Body

Space capture actuators face problems such as insufficient flexibility and electrical components that are vulnerable to extreme space environments. To address these problems, a centralized-driven flexible continuous robot based on a multiple scissor mechanism units is proposed in this study. The continuous robot body is composed of two scissor mechanism units coupled in series, and the base container’s three motors to drive the robot. The two scissor mechanism units ensure a wide range of flexible operations and the light weight of the robot. The centralized drive with three motors not only reduces the number of driving sources, but also ensures temperature control and protection of electrical components in the space environment. The kinematics and dynamics of the robot are analyzed, and the workspace and deformation performance of the robot are verified through experiments. Compared with other continuous robots, the proposed continuous robot retains the characteristics of continuous robots in a wide range of flexible operations. At the same time, the configuration is light and a small number of driving sources are used, which is suitable for extreme temperatures, vacuum, radiation, and strict resource-constrained environments in space.

Performance of Elastomeric Silicones in Ablative and Space Environments

1966 ◽  
Vol 39 (4) ◽  
pp. 1247-1257 ◽  
Author(s):  
Clyde L. Whipple ◽  
John A. Thorne
Keyword(s):  
High Vacuum ◽  
Thermal Control ◽  
Heat Fluxes ◽  
Space Environment ◽  
Space Applications ◽  
Wide Range ◽  
Environmental Extremes ◽  
Temperature Ranges ◽  
Space Environments ◽  
Thermal Control Coatings

Abstract Elastomeric silicones are among the best materials available for many ablative and space applications. In ablative applications, these materials protect launching equipment, safeguard various parts of vehicles and spacecraft during flight, and shield re-entering spacecraft. Generally, elastomeric silicones are used where ablative conditions involve low to moderate heat fluxes and shear forces. Ablative characteristics of materials can vary widely depending on polymer type, fillers, and applications techniques, and no one elastomeric silicone will perform in a wide range of ablative missions. A good knowledge of the ablative characteristics of silicone materials is required to select the best candidates for a given application. In the space environment, silicones are often used for seals, thermal control coatings, potting materials, and other applications because they perform well over wide temperature ranges, and because they are inherently stable to high-vacuum and ultraviolet conditions. Data given in this paper illustrate that silicones show little weight loss or loss of properties on exposure to space environmental extremes. Furthermore, these losses can be made almost negligible by proper conditioning of the finished elastomer.

Numerical Simulation of Droplet Generation in Series Co-Flow Capillaries

2009 ◽  
Author(s):  
Yanxi Song ◽  
Jinliang Xu
Keyword(s):  
Reynolds Number ◽  
Disperse Phase ◽  
Weber Number ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Disperse Flow ◽  
Double Emulsions ◽  
Wide Range ◽  
In Series ◽  
Dispersed Phases

We study the production and motion of monodisperse double emulsions in microfluidics comprising series co-flow capillaries. Both two and three dimensional simulations are performed. Flow was determined by dimensionless parameters, i.e., Reynolds number and Weber number of continuous and dispersed phases. The co-flow generated droplets are sensitive to the Reynolds number and Weber number of the continuous phase, but insensitive to those of the disperse phase. Because the inner and outer drops are generate by separate co-flow processes, sizes of both inner and outer drops can be controlled by adjusting Re and We for the continuous phase. Meanwhile, the disperse phase has little effect on drop size, thus a desirable generation frequency of inner drop can be reached by merely adjusting flow rate of the inner fluid, leading to desirable number of inner drops encapsulated by the outer drop. Thus highly monodisperse double emulsions are obtained. It was found that only in dripping mode can droplet be of high mono-dispersity. Flow begins to transit from dripping regime to jetting regime when the Re number is decreased or Weber number is increased. To ensure that all the droplets are produced over a wide range of running parameters, tiny tapered tip outlet for the disperse flow should be applied. Smaller the tapered tip, wider range for Re and we can apply.

Small Screen, Big Feels

2020 ◽  
Author(s):  
Melissa Ames
Keyword(s):  
United States ◽  
The United States ◽  
Presidential Debates ◽  
Audience Studies ◽  
The Walking Dead ◽  
Wide Range ◽  
In Series ◽  
Fear And Anxiety ◽  
Small Screen ◽  
Network Era

While television has always played a role in recording and curating history, shaping cultural memory, and influencing public sentiment, the changing nature of the medium in the post-network era finds viewers experiencing and participating in this process in new ways. They skim through commercials, live tweet press conferences and award shows, and tune into reality shows to escape reality. This new era, defined by the heightened anxiety and fear ushered in by 9/11, has been documented by our media consumption, production, and reaction. In Small Screen, Big Feels, Melissa Ames asserts that TV has been instrumental in cultivating a shared memory of emotionally charged events unfolding in the United States since September 11, 2001. She analyzes specific shows and genres to illustrate the ways in which cultural fears are embedded into our entertainment in series such as The Walking Dead and Lost or critiqued through programs like The Daily Show. In the final section of the book, Ames provides three audience studies that showcase how viewers consume and circulate emotions in the post-network era: analyses of live tweets from Shonda Rhimes's drama, How to Get Away with Murder (2010--2020), ABC's reality franchises, The Bachelor (2002--present) and The Bachelorette (2003--present), and political coverage of the 2016 Presidential Debates. Though film has been closely studied through the lens of affect theory, little research has been done to apply the same methods to television. Engaging an impressively wide range of texts, genres, media, and formats, Ames offers a trenchant analysis of how televisual programming in the United States responded to and reinforced a cultural climate grounded in fear and anxiety.

Epilogue

2020 ◽  
pp. 206-210
Author(s):  
James S.J. Schwartz
Keyword(s):  
Space Environment ◽  
Opportunity Costs ◽  
Scientific Exploration ◽  
The Future ◽  
Future Value ◽  
Human Habitation ◽  
A Priority ◽  
Space Environments ◽  
The Cost

This concluding chapter argues that scientific exploration of the space environment should remain a priority even if space settlements are established, and even if technological breakthroughs decrease the cost of spaceflight enough to increase spaceflight activities by orders of magnitude. It addresses the enduring need to engage in scientific examination in order to establish the viability of space environments for human habitation. It also reaffirms the value of scientific exploration, knowledge, and understanding—which will only become more significant in space societies, if they are ever established. The Epilogue concludes by addressing the possible development of revolutionary technologies, the opportunity costs associated with prioritizing scientific exploration, and the future value of scientific exploration, knowledge, and understanding in space.

Flexible Metamaterials RF Filters Implemented through Micromachining LCP Substrates

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 000555-000579
Author(s):  
Jonathan Richard ◽  
Robert Dean
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Flexible Substrate ◽  
Ring Resonators ◽  
Split Ring ◽  
Pass Filter ◽  
Split Ring Resonators ◽  
Wide Range ◽  
In Series ◽  
Invisibility Cloaks

Metamaterials have a wide range of potential uses in areas such as optics, transmission lines, and RF design. The simplest metamaterial structures are Split-Ring Resonators (SRR) and Complementary Split-Ring Resonators (CSSR). Through the combination of various forms of these structures, different applications in the areas previously stated can be achieved. Under this investigation, a metamaterials transmission line was realized through micromachining a Liquid Crystal Polymer (LCP) substrate. Not only does LCP possess useful RF properties, it can also be easily micromachined. This transmission line consisted of several CSSRs in series, which performed as a high-order, high-frequency high-pass filter. This structure was unique to most metamaterial structures because LCP is a flexible substrate. It was observed that the resonant frequency of the filter did not change when the LCP transmission line was flexed in various ways. Next, micromachined vias were etched through the LCP substrate to demonstrate that these features do not affect the filter's response. Through utilization of these vias, the metamaterial structures can be physically conformed to nearly any shape or mounted onto another object without affecting the filter's response. As demonstrated in a simple filter structure, the shape manipulation has very little effect. Theoretically, extrapolating these methods to the development of metamaterials 3D RF invisibility cloaks, that are easily realizable and mountable onto an object, could prove useful.

scholarly journals Motion Planning and Iterative Learning Control of a Modular Soft Robotic Snake

2020 ◽  
Vol 7 ◽  
Author(s):  
Ming Luo ◽  
Zhenyu Wan ◽  
Yinan Sun ◽  
Erik H. Skorina ◽  
Weijia Tao ◽  
...  
Keyword(s):  
Motion Planning ◽  
Disaster Response ◽  
Iterative Learning Control ◽  
Learning Control ◽  
Iterative Learning ◽  
Curvature Sensing ◽  
Important Research Topic ◽  
Wide Range ◽  
Constrained Environments ◽  
High Degree

Snake robotics is an important research topic with a wide range of applications, including inspection in confined spaces, search-and-rescue, and disaster response. Snake robots are well-suited to these applications because of their versatility and adaptability to unstructured and constrained environments. In this paper, we introduce a soft pneumatic robotic snake that can imitate the capabilities of biological snakes, its soft body can provide flexibility and adaptability to the environment. This paper combines soft mobile robot modeling, proprioceptive feedback control, and motion planning to pave the way for functional soft robotic snake autonomy. We propose a pressure-operated soft robotic snake with a high degree of modularity that makes use of customized embedded flexible curvature sensing. On this platform, we introduce the use of iterative learning control using feedback from the on-board curvature sensors to enable the snake to automatically correct its gait for superior locomotion. We also present a motion planning and trajectory tracking algorithm using an adaptive bounding box, which allows for efficient motion planning that still takes into account the kinematic state of the soft robotic snake. We test this algorithm experimentally, and demonstrate its performance in obstacle avoidance scenarios.

scholarly journals Generation of Electricity Using Microbial Fuel Cell (MFC) from Sludge

2019 ◽  
Vol 35 (1) ◽  
pp. 23-26
Author(s):  
Eti Barua ◽  
Md Saddam Hossain ◽  
Modhusudon Shaha ◽  
Ekramul Islam ◽  
Fatema Tuj Zohora ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Power Sector ◽  
Promising Alternative ◽  
Power Sources ◽  
Renewable Biomass ◽  
Wide Range ◽  
In Series ◽  
Complex Organic ◽  
Important Form

Microbial fuel cell (MFC), recently, is considered as a promising alternative to traditional power sources as it can use microorganisms to transform chemical energy of organic compounds into electricity. In future, microbial production of electricity may become an important form of bioenergy because electricity extraction is possible through MFC using wide range soluble or nonsoluble complex organic wastes as a renewable biomass. In this study, single chamber MFC and double chambers MFCs were used to production and enrichment a microbial consortium for electricity generation from organic waste samples. Potential electrogenic bacteria were also isolated from anode, analyzed and evaluated. Most of them were Gram negative and fermentative organisms. Their electrogenic role was promising generating upto 5.05 volts and 4.72 mA when combined five) double chambers in series connection. Isolation of these bacteria and employing these for generation of electricity may bring potential power sector endeavor in future. Bangladesh J Microbiol, Volume 35 Number 1 June 2018, pp 23-26

scholarly journals Architecture of the sarcomere matrix of skeletal muscle: immunoelectron microscopic evidence that suggests a set of parallel inextensible nebulin filaments anchored at the Z line.

1988 ◽  
Vol 107 (6) ◽  
pp. 2199-2212 ◽  
Author(s):  
K Wang ◽  
J Wright
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Smooth Muscles ◽  
Psoas Muscle ◽  
Immunoblot Analysis ◽  
Cross Reactivity ◽  
Wide Range ◽  
Determining Factors ◽  
Myosin Filaments ◽  
In Series

Nebulin, a giant myofibrillar protein (600-800 kD) that is abundant (3%) in the sarcomere of a wide range of skeletal muscles, has been proposed as a component of a cytoskeletal matrix that coexists with actin and myosin filaments within the sarcomere. Immunoblot analysis indicates that although polypeptides of similar size are present in cardiac and smooth muscles at low abundance, those proteins show no immunological cross-reactivity with skeletal muscle nebulin. Gel analysis reveals that nebulins in various skeletal muscles of rabbit belong to at least two classes of size variants. A monospecific antibody has been used to localize nebulin by immunoelectron microscopy in a mechanically split rabbit psoas muscle fiber preparation. Labeled split fibers exhibit six pairs of stripes of antibody-imparted transverse densities spaced at 0.1-1.0 micron from the Z line within each sarcomere. These epitopes maintain a fixed distance to the Z line irrespective of sarcomere length and do not exhibit the characteristic elastic stretch-response of titin epitopes within the I band domain. It is proposed that nebulin constitutes a set of inextensible filaments attached at one end to the Z line and that nebulin filaments are in parallel, and not in series, with titin filaments. Thus the skeletal muscle sarcomere may have two sets of nonactomyosin filaments: a set of I segment-linked nebulin filaments and a set of A segment-linked titin filaments. This four-filament sarcomere model raises the possibility that nebulin and titin might act as organizing templates and length-determining factors for actin and myosin respectively.

scholarly journals Transitive inference in Polistes paper wasps

2019 ◽  
Vol 15 (5) ◽  
pp. 20190015 ◽  
Author(s):  
Elizabeth A. Tibbetts ◽  
Jorge Agudelo ◽  
Sohini Pandit ◽  
Jessica Riojas
Keyword(s):  
Nervous System ◽  
Transitive Inference ◽  
Paper Wasps ◽  
Social Hierarchies ◽  
Polistes Metricus ◽  
Wide Range ◽  
Growing Body ◽  
In Series ◽  
Five Elements ◽  
Underlying Dimension

Transitive inference (TI) is a form of logical reasoning that involves using known relationships to infer unknown relationships (A > B; B > C; then A > C). TI has been found in a wide range of vertebrates but not in insects. Here, we test whether Polistes dominula and Polistes metricus paper wasps can solve a TI problem. Wasps were trained to discriminate between five elements in series (A 0 B−, B 0 C−, C 0 D−, D 0 E−), then tested on novel, untrained pairs (B versus D). Consistent with TI, wasps chose B more frequently than D. Wasps organized the trained stimuli into an implicit hierarchy and used TI to choose between untrained pairs. Species that form social hierarchies like Polistes may be predisposed to spontaneously organize information along a common underlying dimension. This work contributes to a growing body of evidence that the miniature nervous system of insects does not limit sophisticated behaviours.

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