3,633 research outputs found
Fighters pilot helmet design for 5th generation aircraft
Fighter pilots’ helmets have become more complex and heavier resulting in long term implications to pilots musculoskeletal systems as they fly and experience high g-load. Current research has identified design changes to the helmet to accommodate the ancillary items fitted to assist pilots but at the expense of comfort and additional loading. Its manufacturing requirements and adaptations to offer bespoke solutions are addressed to allow for training and operational usage. To produce the next generation of helmets that reduce long-term injuries, from g-loads and asymmetrical ancillaries requires individual considerations, unique manufacturing requirements and the ability to support with service spares anywhere in the world at short notice. This paper will describe how manufacturing requirements are matched to ergonomic needs and bespoke components can support global demands
Improving Big Data Visual Analytics with Interactive Virtual Reality
For decades, the growth and volume of digital data collection has made it
challenging to digest large volumes of information and extract underlying
structure. Coined 'Big Data', massive amounts of information has quite often
been gathered inconsistently (e.g from many sources, of various forms, at
different rates, etc.). These factors impede the practices of not only
processing data, but also analyzing and displaying it in an efficient manner to
the user. Many efforts have been completed in the data mining and visual
analytics community to create effective ways to further improve analysis and
achieve the knowledge desired for better understanding. Our approach for
improved big data visual analytics is two-fold, focusing on both visualization
and interaction. Given geo-tagged information, we are exploring the benefits of
visualizing datasets in the original geospatial domain by utilizing a virtual
reality platform. After running proven analytics on the data, we intend to
represent the information in a more realistic 3D setting, where analysts can
achieve an enhanced situational awareness and rely on familiar perceptions to
draw in-depth conclusions on the dataset. In addition, developing a
human-computer interface that responds to natural user actions and inputs
creates a more intuitive environment. Tasks can be performed to manipulate the
dataset and allow users to dive deeper upon request, adhering to desired
demands and intentions. Due to the volume and popularity of social media, we
developed a 3D tool visualizing Twitter on MIT's campus for analysis. Utilizing
emerging technologies of today to create a fully immersive tool that promotes
visualization and interaction can help ease the process of understanding and
representing big data.Comment: 6 pages, 8 figures, 2015 IEEE High Performance Extreme Computing
Conference (HPEC '15); corrected typo
Joining Methods For Continuous Fiber Reinforced Thermoplastic Composites In Structural Applications
Continuous fiber reinforced thermoplastic (CFRTP) composites have been proposed as an alternative to metals in structural applications. CFRTP composites can be used to create structures that are lighter weight, have better resistance to environmental factors, and have the potential to be recycled. However, one of the main challenges to CFRTP composites is connections between structural members. The goal of this thesis is to investigate the feasibility of joining CFRTP composites to both similar and dissimilar materials through literature review, coupon testing, design of a structural joint, and a small scale laboratory prototype of the joint. To achieve this goal the following steps were implemented.
1) Conduct a literature review to determine the state of the art in joining methods, optimal thermoplastic materials to use, and appropriate computer modeling techniques for joints.
2) Perform coupon level testing to obtain standard mechanical properties of the thermoplastic materials, and to characterize material joining methods.
3) Design a structural CFRTP composite joint.
4) Test a small scale prototype of the joint for design validation.
Two joining methods were selected to be examine: adhesive bonding and mechanical fastening. Carbon fiber-Polyphenylene sulfide (PPS) unidirectional composite tape was selected to consolidate plates with quasi-isotropic layups. Lap shear joints were examined using experimental evaluations. The experiments serve to characterize the mechanical properties required for structural design using the proposed joining methods: adhesive bonding strength and fastener bearing strength. In addition, a comprehensive program of standard tests for material characterization of the CFRTP composite were conducted to generate properties for structural analysis. A structural model of a connection in a bridging structure was developed using finite element analysis. Lastly, a prototype of the joint was constructed and tested
Trend Inflation, Wage and Price Rigidities, and Welfare
This paper studies the steady-state costs of inflation in a general-equilibrium model with real per capita output growth and staggered nominal price and wage contracts. Our analysis shows that trend inflation has important effects on the economy when combined with nominal contracts and real output growth. Steady-state output and welfare losses are quantitatively important even for low values of trend inflation. Further, we show that nominal wage contracting is quantitatively more important than nominal price contracting in generating these losses. This important result does not arise from price dispersion per se but from an effect of nominal output growth on the optimal markup of monopolistically competitive labour suppliers. We also demonstrate that accounting for productivity growth is important for calculating the welfare costs of inflation. Indeed, the presence of two percent productivity growth increases the welfare costs of inflation in our benchmark specification by a factor of four relative to the nogrowth case.Inflation: costs and benefits
Beyond the blank cheque: Arming iran during the ford administration
© 2016 Taylor & Francis. When President Gerald Ford decided tomaintain and deepen arms relations with Iran, he cemented a momentum that became near impossible for a successor to break by continuing the policy of his predecessor Richard Nixon. Nixon had given the Shah of Iran a "blank cheque" to purchase whatever American arms he desired- short of nuclear weapons. Although Ford’s authority would be challenged by members of his own Administration and a Congress seeking to claw back some of its authority, the need to support allies in the Middle East against the threat of the Soviet Union, even during a time of détente, remained paramount
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