Challenges and Opportunities in Multifunctional Nanocomposite Structures for Aerospace Applications

MRS Bulletin ◽  
2007 ◽  
Vol 32 (4) ◽  
pp. 328-334 ◽  
Author(s):  
Jeff Baur ◽  
Edward Silverman
Keyword(s):  
Composite Structures ◽  
Reinforced Composites ◽  
Aerospace Applications ◽  
Structural Applications ◽  
Challenges And Opportunities ◽  
The Status ◽  
Hierarchical Composites ◽  
Easy Integration ◽  
Nanocomposite Structures ◽  
Made In

AbstractOne important application of nanocomposites is their use in engineered structural composites. Among the wide variety of structural applications, fiber-reinforced composites for aerospace structures have some of the most demanding physical, chemical, electrical, thermal, and mechanical property requirements. Nanocomposites offer tremendous po tential to improve the properties of advanced engineered composites with modest additional weight and easy integration into current proc essing schemes. Sig nificant progress has been made in fulfilling this vision. In particular, nanocomposites have been applied at numerous locations within hierarchical composites to improve specific properties and optimize the multifunctional properties of the overall structure. Within this ar ticle, we review the status of nanocomposite incorporation into aerospace composite structures and the need for continued development.

Past, Present and Future Composite Structures Applications in Rotorcraft

1999 ◽  
Author(s):  
Carl Rousseau ◽  
Al Dobyns ◽  
Pierre Minguet
Keyword(s):  
Composite Structures ◽  
Rotor Blades ◽  
Reinforced Composites ◽  
Main Rotor ◽  
Weight Percentage ◽  
Advanced Composite ◽  
Highest Weight ◽  
Structural Applications ◽  
Complex Curvature ◽  
Military Production

Abstract The rotorcraft industry is a roughly $5B/year segment of aerospace, with a 4:1 military to civil sales ratio, that delivers on the order of 5000–6000 aircraft per year. The earliest rotorcraft had composite primary structure: bonded wooden main and tail rotor blades. The first advanced composite main rotor (M/R) and tail rotor blades (bonded glass/epoxy D-spars, honeycomb afterbodies, and fabric skins) went into production in the early ’70’s. Thus, the rotorcraft industry has been designing and certifying nonredundant bonded primary composite structure for over 25 years. More recent design innovations for rotor components include 4-inch-thick solid molded bearingless M/R hubs and yokes (joining the blades to the mast) and a 1.5-inch-thick complex curvature fiber placed carbon grip for the Bell/Boeing MV-22 Osprey tiltrotor. With roughly 50% of its empty weight consisting of glass and carbon reinforced composites, the V-22 probably has the highest weight-percentage of composites of any manned military production aircraft. This degree of composites usage will likely be surpased by the Sikorsky/Boeing RAH-66 Comanche scout/attack helicopter when it goes into production. As with the V-22 and RAH-66, composites are also seeing increased usage in civilian rotorcraft airframes. Specifically, the Bell 427 and MD Helicopter MD900 Explorer light twin helicopters feature all-composite fuselages, while the Bell-Agusta BA609 civil tiltrotor will have carbon epoxy wings, fuselage and empennage much like the V-22. In the future, composite structural applications will become more widespread as designers gain insight and confidence. Repair, maintenance and support of these structures will become the focus of much engineering R&D effort.

scholarly journals Brief Review of Photocatalysis and Photoresponse Properties of ZnO–Graphene Nanocomposites

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6403
Author(s):  
Chenhao Gao ◽  
Keyi Zhong ◽  
Xuan Fang ◽  
Dan Fang ◽  
Hongbin Zhao ◽  
...  
Keyword(s):  
Composite Structures ◽  
Carrier Transport ◽  
Physicochemical Characteristics ◽  
Wide Bandgap ◽  
Graphene Nanocomposites ◽  
Graphene Nanocomposite ◽  
The Common ◽  
General Physical ◽  
Nanocomposite Structures ◽  
Made In

As a typical wide bandgap semiconductor, ZnO has received a great deal of attention from researchers because of its strong physicochemical characteristics. During the past few years, great progress has been made in the optoelectronic applications of ZnO, particularly in the photocatalysis and photodetection fields. To enable further improvements in the material’s optoelectronic performance, construction of a variety of ZnO-based composite structures will be essential. In this paper, we review recent progress in the growth of different ZnO–graphene nanocomposite structures. The related band structures and photocatalysis and photoresponse properties of these nanocomposites are discussed. Additionally, specific examples of the materials are included to provide an insight into the common general physical properties and carrier transport characteristics involved in these unique nanocomposite structures. Finally, further directions for the development of ZnO–graphene nanocomposite materials are forecasted.

scholarly journals Experimental characterisation of rate-dependent compression behaviour of fibre reinforced composites

2018 ◽  
Vol 183 ◽  
pp. 02053
Author(s):  
Mehtab V. Pathan ◽  
Borja Erice ◽  
Sathiskumar A. Ponnusami ◽  
Nik Petrinic
Keyword(s):  
Composite Structures ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Strain Rates ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Analysis And Design ◽  
Rate Dependent ◽  
Wide Range ◽  
Structural Applications

Fibre reinforced polymers (FRP) materials are being increasingly used for aerospace and automotive structural applications. One of the critical loading conditions for such applications is impact, consequently, understanding of the composite behavior under such loads becomes critical for structural design. The analysis and design process for achieving impact-resistant composite structures requires rate-dependent constitutive models, which, in turn, requires material properties of the composite over a range of strain rates. It is, therefore, the objective of the research to investigate the strain rate-dependent behavior of fiber reinforced composites under compressive loads for a wide range of fiber orientations. Quasi-static (≈ 1e-3 s−1) and high loading (≈ 200 s−1) rates are considered for the experimental study. Accordingly, two different test setups are utilized, a screw-driven universal testing machine for quasi-static tests and a Split Hopkinson Pressure Bar (SHPB) system for dynamic tests. The stress-strain response of the composite is reported for the different fiber orientations and the strain rates, revealing the rate-dependent characteristics of the carbon fiber reinforced composite. From the test results, it is observed that, the dependency of the fracture strength on the loading rate is significant. The results are summarised in terms of the failure envelope in the transverse compression-in-plane shear σ22 − σ12 plane for the two strain rates.

Information in United States Patents on works related to ‘Natural Fibers’: 2000-2018

2019 ◽  
Vol 12 (1) ◽  
pp. 4-76 ◽  
Author(s):  
Krittirash Yorseng ◽  
Mavinkere R. Sanjay ◽  
Jiratti Tengsuthiwat ◽  
Harikrishnan Pulikkalparambil ◽  
Jyotishkumar Parameswaranpillai ◽  
...  
Keyword(s):  
United States ◽  
Composite Materials ◽  
Natural Fiber ◽  
Comprehensive Evaluation ◽  
Natural Fibers ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Macro Scale ◽  
Structural Applications

Background: This era has seen outstanding achievements in materials science through the advances in natural fiber-based composites. The new environmentally friendly and sustainability concerns have imposed the chemists, biologists, researchers, engineers, and scientists to discover the engineering and structural applications of natural fiber reinforced composites. Objective: To present a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials. Methods: The patent data have been taken from the external links of US patents such as IFI CLAIMS Patent Services, USPTO, USPTO Assignment, Espacenet, Global Dossier, and Discuss. Results: The present world scenario demands the usage of natural fibers from agricultural and forest byproducts as a reinforcement material for fiber reinforced composites. Natural fibers can be easily extracted from plants and animals. Recently natural fiber in nanoscale is preferred over micro and macro scale fibers due to its superior thermo-mechanical properties. However, the choice of macro, micro, and nanofibers depends on their applications. Conclusion: This document presents a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials.

Mobile to Fuel Explosive Ecommerce Growthin india

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Priya Yadav ◽  
Pranjeet Das ◽  
Ravi Kumar Malhotra
Keyword(s):  
Developing Countries ◽  
Electronic Commerce ◽  
Rapid Development ◽  
Global Markets ◽  
Network Technology ◽  
Mobile Terminals ◽  
Doing Business ◽  
Is Security ◽  
Challenges And Opportunities ◽  
Made In

E-commerce is process of doing business through computer networks. Advances in wireless network technology and the continuously increasing number of users of mobile latter on make an ideal platform for offering various high utilityservices in just a snap of a finger to the mobile users and give pace to the rapid development of E-Commerce in India.E-commerce is considered an excellent alternative for companies to reach new customersbut the fact that has hindered the growth of e-commerce is security. Security is the challenge facing e-commerce today and there is still a lot of advancement made in the field of securityfor increasing the use of e-commerce in developing countries the B2B e-commerce is implemented for improving access to global markets for firms in developing countries. With the special characteristics and constraints of mobile terminals and wireless networks and the context, situations and circumstances that people use their hand-held terminalswhich will ultimately fuel explosive ecommerce growth in India This paper highlights the various key challenges and opportunities which Indian e-commerce industry may face in the upcoming years. And also discuss challenges in electronic commerce transactions.

Against Permanent Sovereignty

2017 ◽  
Author(s):  
Chris Armstrong
Keyword(s):  
Natural Resources ◽  
International Politics ◽  
Local Communities ◽  
Status Quo ◽  
Nation States ◽  
The Status ◽  
Made In

The status quo within international politics is that individual nation-states enjoy extensive and for the most part exclusive rights over the resources falling within their borders. Egalitarians have often assumed that such a situation cannot be defended, but perhaps some sophisticated defences of state or national rights over natural resources which have been made in recent years prove otherwise. This chapter critically assesses these various arguments, and shows that they are not sufficient to justify the institution of ‘permanent sovereignty’ over resources. Even insofar as those arguments have some weight, they are compatible with a significant dispersal of resource rights away from individual nation-states, both downwards towards local communities, and upwards towards transnational and global agencies.

scholarly journals Democratizing ownership and participation in the 4th Industrial Revolution: challenges and opportunities in cellular agriculture

2021 ◽  
Author(s):  
Robert M. Chiles ◽  
Garrett Broad ◽  
Mark Gagnon ◽  
Nicole Negowetti ◽  
Leland Glenna ◽  
...  
Keyword(s):  
Business Models ◽  
Industrial Revolution ◽  
Cultured Cells ◽  
Advanced Materials ◽  
High Stakes ◽  
Digital Platforms ◽  
Challenges And Opportunities ◽  
The Status ◽  
Political Economic ◽  
Industry Sectors

AbstractThe emergence of the “4th Industrial Revolution,” i.e. the convergence of artificial intelligence, the Internet of Things, advanced materials, and bioengineering technologies, could accelerate socioeconomic insecurities and anxieties or provide beneficial alternatives to the status quo. In the post-Covid-19 era, the entities that are best positioned to capitalize on these innovations are large firms, which use digital platforms and big data to orchestrate vast ecosystems of users and extract market share across industry sectors. Nonetheless, these technologies also have the potential to democratize ownership, broaden political-economic participation, and reduce environmental harms. We articulate the potential sociotechnical pathways in this high-stakes crossroads by analyzing cellular agriculture, an exemplary 4th Industrial Revolution technology that synergizes computer science, biopharma, tissue engineering, and food science to grow cultured meat, dairy, and egg products from cultured cells and/or genetically modified yeast. Our exploration of this space involved multi-sited ethnographic research in both (a) the cellular agriculture community and (b) alternative economic organizations devoted to open source licensing, member-owned cooperatives, social financing, and platform business models. Upon discussing how these latter approaches could potentially facilitate alternative sociotechnical pathways in cellular agriculture, we reflect upon the broader implications of this work with respect to the 4th Industrial Revolution and the enduring need for public policy reform.

GDNF Therapy: Can We Make It Work?

2021 ◽  
pp. 1-4
Author(s):  
Anders Björklund
Keyword(s):  
Gene Therapy ◽  
Transcription Factor ◽  
Signaling Pathway ◽  
Therapeutic Potential ◽  
Threshold Level ◽  
New Findings ◽  
The Status ◽  
Interesting Discussion ◽  
Postmortem Studies ◽  
Made In

In two recent postmortem studies, Jeffrey Kordower and colleagues report new findings that open up for an interesting discussion on the status of GDNF/NRTN signaling in patients with Parkinson’s disease (PD), adding an interesting perspective on the, admittedly very limited, signs of restorative effects previously seen in GDNF/NRTN-treated patients. Their new findings show that the level of the GDNF signaling receptor Ret is overall reduced by about 65% relative to non-PD controls, and most severely, up to 80%, in nigral neurons containing α-synuclein inclusions, accompanied by impaired signaling downstream of the Ret receptor. Notably, however, the vast majority of the remaining nigral neurons retained a low level of Ret expression, and hence a threshold level of signaling. Further observations made in two patients who had received AAV-NRTN gene therapy 8–10 years earlier suggest the intriguing possibility that NRTN is able to restore Ret expression and upregulate its own signaling pathway. This “wind-up” mechanism, which is likely to depend on an interaction with dopaminergic transcription factor Nurr1, has therapeutic potential and should encourage renewed efforts to turn GDNF/NRTN therapy into success, once the recurring problem of under-dosing is resolved.

Marketing and delivering information literacy on the web, yesterday and today, from 2009 to 2012

2014 ◽  
Vol 31 (4) ◽  
pp. 10-13 ◽  
Author(s):  
Sharon Q. Yang
Keyword(s):  
Information Literacy ◽  
Web Sites ◽  
Academic Libraries ◽  
Design Methodology ◽  
Status Quo ◽  
Content Type ◽  
The Status ◽  
Practical Implications ◽  
The Web ◽  
Made In

Purpose – This study aims to ascertain the trends and changes of how academic libraries market and deliver information literacy (IL) on the web. Design/methodology/approach – The author compares the findings from two separate studies that scanned the Web sites for IL-related activities in 2009 and 2012, respectively. Findings – Academic libraries intensified their efforts to promote and deliver IL on the web between 2009 and 2012. There was a significant increase in IL-related activities on the web in the three-year period. Practical implications – The findings describe the status quo and changes in IL-related activities on the libraries’ Web sites. This information may help librarians to know what they have been doing and if there is space for improvement. Originality/value – This is the only study that spans three years in measuring the progress librarians made in marketing and delivering IL on the Web.

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