Read by QxMD icon Read


Y Y Chen, R Zhu, M V Barnhart, G L Huang
Increasing sensitivity and signal to noise ratios of conventional wave sensors is an interesting topic in structural health monitoring, medical imaging, aerospace and nuclear instrumentation. Here, we report the concept of a gradient piezoelectric self-sensing system by integrating shunting circuitry into conventional sensors. By tuning circuit elements properly, both the quality and quantity of the flexural wave measurement data can be significantly increased for new adaptive sensing applications. Through analytical, numerical and experimental studies, we demonstrate that a metamaterial-based sensing system (MBSS) with gradient bending stiffness can be designed by connecting gradient negative capacitance circuits to an array of piezoelectric patches (sensors)...
October 17, 2016: Scientific Reports
Jun Huang, Zude Zhou, Lin Zhang, Juntao Chen, Chunqian Ji, Duc Truong Pham
Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented...
2016: Sensors
Dongping Zhan, Lianhuan Han, Jie Zhang, Kang Shi, Jian-Zhang Zhou, Zhao-Wu Tian, Zhong-Qun Tian
In the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly, ECM possesses several advantages over mechanical machining, such as high removal rate, the capability of making complex three-dimensional structures, and the practicability for difficult-to-cut materials...
September 26, 2016: Accounts of Chemical Research
Jenifer N Saldanha, Santosh Pandey, Jo Anne Powell-Coffman
As we seek to recognize the opportunities of advanced aerospace technologies and spaceflight, it is increasingly important to understand the impacts of hypergravity, defined as gravitational forces greater than those present on the earth's surface. The nematode Caenorhabditis elegans has been established as a powerful model to study the effects of altered gravity regimens and has displayed remarkable resilience to space travel. In this study, we investigate the effects of short-term and defined hypergravity exposure on C...
August 2016: Life Sciences in Space Research
(no author information available yet)
No abstract text is available yet for this article.
2016: Aerospace Medicine and Human Performance
Kevin C Dietrich
BACKGROUND: Central serous chorioretinopathy (CSC) is usually a self-limiting condition; however, there is potential for recurrence and permanent visual defects. Aviation demands perfect vision to minimize risk to pilots and aircraft. Consequently, this ailment disqualifies pilots and pilots to be. CASE REPORT: A fully trained fighter pilot with 1260 h in fighter airframes has been contending with central serous chorioretinopathy in the right eye over the course of 3 yr...
2016: Aerospace Medicine and Human Performance
Robert A Mulcahy, Rebecca S Blue, Johnené L Vardiman, Tarah L Castleberry, James M Vanderploeg
INTRODUCTION: Anxiety may present challenges for commercial spaceflight operations, as little is known regarding the psychological effects of spaceflight on laypersons. A recent investigation evaluated measures of anxiety during centrifuge-simulated suborbital commercial spaceflight, highlighting the potential for severe anxiousness to interrupt spaceflight operations. METHODS: To pave the way for future research, an extensive literature review identified existing knowledge that may contribute to formation of interventions for anxiety in commercial spaceflight...
2016: Aerospace Medicine and Human Performance
Wei Zhu, Chunze Yan, Yunsong Shi, Shifeng Wen, Jie Liu, Qingsong Wei, Yusheng Shi
A novel method based on selective laser sintering (SLS) process is proposed for the first time to prepare complex and high-performance carbon fibres/polyamide12/epoxy (CF/PA12/EP) ternary composites. The procedures are briefly described as follows: prepare polyamide12 (PA12) coated carbon fibre (CF) composite powder; build porous green parts by SLS; infiltrate the green parts with high-performance thermosetting epoxy (EP) resin; and finally cure the resin at high temperature. The obtained composites are a ternary composite system consisting of the matrix of novolac EP resin, the reinforcement of CFs and the transition thin layer of PA12 with a thickness of 595 nm...
2016: Scientific Reports
Zhaoxuan Wu, W A Curtin
Hexagonal close-packed (hcp) metals such as Mg, Ti, and Zr are lightweight and/or durable metals with critical structural applications in the automotive (Mg), aerospace (Ti), and nuclear (Zr) industries. The hcp structure, however, brings significant complications in the mechanisms of plastic deformation, strengthening, and ductility, and these complications pose significant challenges in advancing the science and engineering of these metals. In hcp metals, generalized plasticity requires the activation of slip on pyramidal planes, but the structure, motion, and cross-slip of the associated [Formula: see text] dislocations are not well established even though they determine ductility and influence strengthening...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
(no author information available yet)
No abstract text is available yet for this article.
September 2016: Aerospace Medicine and Human Performance
(no author information available yet)
No abstract text is available yet for this article.
August 2016: Aerospace Medicine and Human Performance
K A Darling, M Rajagopalan, M Komarasamy, M A Bhatia, B C Hornbuckle, R S Mishra, K N Solanki
Nanocrystalline metals, with a mean grain size of less than 100 nanometres, have greater room-temperature strength than their coarse-grained equivalents, in part owing to a large reduction in grain size. However, this high strength generally comes with substantial losses in other mechanical properties, such as creep resistance, which limits their practical utility; for example, creep rates in nanocrystalline copper are about four orders of magnitude higher than those in typical coarse-grained copper. The degradation of creep resistance in nanocrystalline materials is in part due to an increase in the volume fraction of grain boundaries, which lack long-range crystalline order and lead to processes such as diffusional creep, sliding and rotation...
September 14, 2016: Nature
Quan Xu, Wenwen Zhang, Chenbo Dong, Theruvakkattil Sreenivasan Sreeprasad, Zhenhai Xia
With millions of years of natural evolution, organisms have achieved sophisticated structures, patterns or textures with complex, spontaneous multifunctionality. Among all the fascinating characteristics observed in biosystems, self-cleaning ability is regarded as one of the most interesting topics in biomimicry because of its potential applications in various fields such as aerospace, energy conversion and biomedical and environmental protection. Recently, in-depth studies have been carried out on various compelling biostructures including lotus leaves, shark skins, butterfly wings and gecko feet...
September 2016: Journal of the Royal Society, Interface
Esra Yuce, Gulperi Koçer, Turan Atila Çini
Aerospace medicine is the medical discipline responsible for assessing and conserving the health, safety, and performance of individuals involved in air and space travel. With the upward trend in airline travel, flight-related oral conditions requiring treatment have become a source of concern for aircrew members. Awareness and treatment of any potential physiological problems for these aircrews have always been critical components of aviation safety. In a flight situation, oral and maxillofacial problems may in fact become life-threatening clinical conditions...
September 2016: General Dentistry
Sehmus Ozden, Leonardo D Machado, ChandraSekhar Tiwary, Pedro A S Autreto, Robert Vajtai, Enrique V Barrera, Douglas S Galvao, Pulickel M Ajayan
Advanced materials with multifunctional capabilities and high resistance to hypervelocity impact are of great interest to the designers of aerospace structures. Carbon nanotubes (CNTs) with their lightweight and high strength properties are alternative to metals and/or metallic alloys conventionally used in aerospace applications. Here we report a detailed study on the ballistic fracturing of CNTs for different velocity ranges. Our results show that the highly energetic impacts cause bond breakage and carbon atom rehybridizations, and sometimes extensive structural reconstructions were also observed...
September 21, 2016: ACS Applied Materials & Interfaces
(no author information available yet)
No abstract text is available yet for this article.
July 2016: Aerospace Medicine and Human Performance
Elizabeth C Atwood, Sandra Englhart, Eckehard Lorenz, Winfried Halle, Werner Wiedemann, Florian Siegert
Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission...
2016: PloS One
Syed Haider Abbas, Jae-Kyeong Jang, Jung-Ryul Lee, Zaeill Kim
Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure...
July 2016: Review of Scientific Instruments
Christian J Long, Nathan D Orloff, Kevin A Twedt, Thomas Lam, Fernando Vargas-Lara, Minhua Zhao, Bharath Natarajan, Keana C Scott, Eric Marksz, Tinh Nguyen, Jack F Douglas, Jabez McClelland, Edward Garboczi, Jan Obrzut, J Alexander Liddle
Carbon nanotube composites are lightweight, multifunctional materials with readily adjustable mechanical and electrical properties-relevant to the aerospace, automotive, and sporting goods industries as high-performance structural materials. Here, we combine well-established and newly developed characterization techniques to demonstrate that ultraviolet (UV) light exposure provides a controllable means to enhance the electrical conductivity of the surface of a commercial carbon nanotube-epoxy composite by over 5 orders of magnitude...
September 7, 2016: ACS Applied Materials & Interfaces
Wanchun Guo, Yin Jia, Kesong Tian, Zhaopeng Xu, Jiao Jiao, Ruifei Li, Yuehao Wu, Ling Cao, Haiyan Wang
UV-triggered self-healing of single microcapsules has been a good candidate to enhance the life of polymer-based aerospace coatings because of its rapid healing process and healing chemistry based on an accurate stoichiometric ratio. However, free radical photoinitiators used in single microcapsules commonly suffer from possible deactivation due to the presence of oxygen in the space environment. Moreover, entrapment of polymeric microcapsules into coatings often involves elevated temperature or a strong solvent, probably leading to swelling or degradation of polymer shell, and ultimately the loss of active healing species into the host matrix...
August 17, 2016: ACS Applied Materials & Interfaces
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"