Shape Shifting Target

2015 ◽  
Vol 137 (05) ◽  
pp. 46-51
Author(s):  
Michael I. Friswell
Keyword(s):  
Smart Materials ◽  
Large Scale ◽  
Control Surface ◽  
Commercial Aircraft ◽  
Accurate Analysis ◽  
Low Weight ◽  
Compliant Control ◽  
Aircraft Performance ◽  
Near Term ◽  
The Cost

This article is a study of morphing aircrafts, which has attracted many research groups around the globe. The unmanned aerial vehicles (UAV) have some attractive features for aeronautic research. An important factor in morphing systems is the scale of the air vehicle on which they will be incorporated. With the development of more accurate analysis tools and advanced smart materials, researchers are once again investigating compliant morphing aircraft to improve aircraft performance. Such an aircraft would have the potential to adapt and optimize their shape to improve flight performance or to achieve multi-objective mission roles. Low aspect ratio wings provide more manoeuvrability and allow for high flight speeds, but at the cost of efficiency. An aircraft can be fast or efficient, but not both. Compliant control surfaces also lack the discontinuities found in hinged mechanisms, and thus have the potential to reduce drag and noise significantly. Compliant structures are promising solutions because of their low weight and maintenance costs. Large-scale morphing on commercial aircraft may not be practical in the near term. But the application of morphing to secondary structures, such as a compliant control surface, is a realistic goal.

Enhanced cruise range prediction for narrow-body turbofan commercial aircraft based on QAR data

2020 ◽  
pp. 1-30
Author(s):  
V.E. Atasoy ◽  
C. Cetek
Keyword(s):  
Environmental Sustainability ◽  
Critical Role ◽  
Percentage Error ◽  
Performance Parameters ◽  
Commercial Aircraft ◽  
Accurate Analysis ◽  
Flight Data ◽  
The Real ◽  
Aircraft Performance ◽  
Range Equation

ABSTRACT Aircraft performance parameters play a critical role in maintaining economic and environmental sustainability in aviation. Furthermore, the ability to calculate aircraft performance parameters accurately for the cruise range contributes to aviation in areas such as the preliminary design of aircraft and air traffic management. This study is focused on cruise range performance, as this is critical to both the evaluation and understanding of the economic and environmental impacts of commercial aircraft. Quick Access Recorders (QAR) data were used for more accurate analysis of the cruise range. The QAR data used in this study included 6,574 short-distance domestic flights by narrow-body turbofan commercial aircraft between 31 different city pairs. To obtain a more accurate cruise range equation, parameters affecting the cruise range performance were determined and studied. First, the drag polar model was improved to take the cambered profile, compressibility effects and cruise airspeeds of commercial aircraft into consideration using the real flight data. Second, Thrust-Specific Fuel Consumption (TSFC) models were compared and the most suitable one for the cruise phase was selected. After these steps, cruise range values were calculated using the Breguet range equation with these improved parameters. When the results of this enhanced range model were compared with the real flight data, the mean absolute percentage error (MAPE) was found to be 2.5% for all the Aircraft and Engine Type Groups (AETGs) considered in the data. This figure corresponds to a 7.9% smaller error than provided by previous range models based on simple parabolic drag polar and TSFC models. According to these results, the application of a simple parabolic drag polar and TSFC is not appropriate for cruise range calculations.

Morphing Aircraft: An Improbable Dream?

2014 ◽  
Author(s):  
Michael I. Friswell
Keyword(s):  
Smart Materials ◽  
Aircraft Design ◽  
System Level ◽  
Accurate Analysis ◽  
Bird Flight ◽  
Limited Region ◽  
Morphing Aircraft ◽  
Wing Sweep ◽  
Aircraft Performance ◽  
Morphing Technology

Compliant aircraft, with a range of deformations comparable to birds, has been a dream for many years. Earlier aviation pioneers tried to replicate aspects of bird flight, but higher air speeds and larger payloads have required aircraft design to deviate from their biological inspiration. The design of conventional fixed wing aircraft can only be optimized for a limited region of the flight envelope; mechanisms such as deployable flaps and wing sweep are used extensively to enlarge this envelope. The development of more accurate analysis tools, advanced smart materials, and the increasingly demands for improved aircraft performance, are driving research into compliant morphing aircraft. These aircraft have the potential to adapt and optimize their shape to improve flight performance or achieve multi-objective mission roles. However this technology has rarely been adopted on production aircraft. This paper will critically review the progress made to date on compliant morphing aircraft research, and summarize the challenges that need to be addressed before such technology can be adopted widely. In particular the need to demonstrate system level performance benefits for morphing technology is emphasized.

scholarly journals Mid-century emission pathways in Japan associated with the global 2 °C goal: national and global models’ assessments based on carbon budgets

2019 ◽  
Vol 162 (4) ◽  
pp. 1913-1927 ◽  
Author(s):  
Ken Oshiro ◽  
Keii Gi ◽  
Shinichiro Fujimori ◽  
Heleen L. van Soest ◽  
Christoph Bertram ◽  
...  
Keyword(s):  
Carbon Capture ◽  
Large Scale ◽  
Carbon Capture And Storage ◽  
Primary Energy ◽  
Low Carbon ◽  
Carbon Budgets ◽  
Global Models ◽  
Near Term ◽  
The Cost ◽  
Low Carbon Energy

Abstract This study assesses Japan’s mid-century low-emission pathways using both national and global integrated assessment models in the common mitigation scenario framework, based on the carbon budgets corresponding to the global 2 °C goal. We examine high and low budgets, equal to global cumulative 1600 and 1000 Gt-CO2 (2011–2100) for global models, and 36 and 31 Gt-CO2 (2011–2050) in Japan for national models, based on the cost-effectiveness allocation performed by the global models. The impacts of near-term policy assumption, including the implementation and enhancement of the 2030 target of the nationally determined contribution (NDC), are also considered. Our estimates show that the low budget scenarios require a 75% reduction of CO2 emissions by 2050 below the 2010 level, which is nearly the same as Japan’s governmental 2050 goal of reducing greenhouse gas emissions by 80%. With regard to near-term actions, Japan’s 2030 target included in the NDC is on track to meet the high budget scenario, whereas it is falling short for the low budget scenario, which would require emission reductions immediately after 2020. Whereas models differ in the type of energy source on which they foresee Japan basing its decarbonization process (e.g., nuclear- or variable renewable energy-dependent), the large-scale deployment of low-carbon energy (nuclear, renewable, and carbon capture and storage) is shared across most models in both the high and low budget scenarios. By 2050, low-carbon energy represents 44–54% of primary energy and 86–97% of electricity supply in the high and low budget scenarios, respectively.

Cost- und Monitoring-Projekt: Zwei neue forstliche Meinungsumfragen im Vergleich | The Cost- and Monitoring-Projects: A Comparison of Two New Forestry Opinion Polls

2000 ◽  
Vol 151 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Stephan Wild-Eck ◽  
Willi Zimmermann
Keyword(s):  
Large Scale ◽  
Forest Policy ◽  
Forest Economics ◽  
Positive Attitudes ◽  
Federal Institute ◽  
Swiss Confederation ◽  
Institute Of Technology ◽  
The Cost ◽  
Near Future ◽  
Opinion Polls

Two large-scale surveys looking at attitudes towards forests, forestry and forest policy in the second half ofthe nineties have been carried out. This work was done on behalf of the Swiss Confederation by the Chair of Forest Policy and Forest Economics of the Federal Institute of Technology (ETH) in Zurich. Not only did the two studies use very different methods, but the results also varied greatly as far as infrastructure and basic conditions were concerned. One of the main differences between the two studies was the fact that the first dealt only with mountainous areas, whereas the second was carried out on the whole Swiss population. The results of the studies reflect these differences:each produced its own specific findings. Where the same (or similar) questions were asked, the answers highlight not only how the attitudes of those questioned differ, but also views that they hold in common. Both surveys showed positive attitudes towards forests in general, as well as a deep-seated appreciation ofthe forest as a recreational area, and a positive approach to tending. Detailed results of the two surveys will be available in the near future.

Waste minimization program in Shuaiba Industrial Area

1999 ◽  
Vol 39 (10-11) ◽  
pp. 289-295
Author(s):  
Saleh Al-Muzaini
Keyword(s):  
Solid Waste ◽  
Power Plants ◽  
Large Scale ◽  
Industrial Area ◽  
Waste Minimization ◽  
Regulatory Body ◽  
Eastern Sector ◽  
Western Sector ◽  
Petroleum Companies ◽  
The Cost

The Shuaiba Industrial Area (SIA) is located about 50 km south of Kuwait City. It accommodates most of the large-scale industries in Kuwait. The total area of the SIA (both eastern and western sectors) is about 22.98 million m2. Fifteen plants are located in the eastern sector and 23 in the western sector, including two petrochemical companies, three refineries, two power plants, a melamine company, an industrial gas corporation, a paper products company and, two steam electricity generating stations, in addition to several other industries. Therefore, only 30 percent of the land in the SIA's eastern sector and 70 percent of land in the SIA's western sector is available for future expansion. Presently, industries in the SIA generate approximately 204,000 t of solid waste. With future development in the industries in the SIA, the estimated quantities will reach 240,000 t. The Shuaiba Area Authority (SAA), a governmental regulatory body responsible for planning and development in the SIA, has recognized the problem of solid waste and has developed an industrial waste minimization program. This program would help to reduce the quantity of waste generated within the SIA and thereby reduce the cost of waste management. This paper presents a description of the waste minimization program and how it is to be implemented by major petroleum companies. The protocols employed in the waste minimization program are detailed.

An Out-of-Core Dataflow Middleware to Reduce the Cost of Large Scale Iterative Solvers

2012 ◽  
Author(s):  
Zheng Zhou ◽  
Erik Saule ◽  
Hasan Metin Aktulga ◽  
Chao Yang ◽  
Esmond G. Ng ◽  
...  
Keyword(s):  
Large Scale ◽  
Iterative Solvers ◽  
The Cost

scholarly journals A Survey on Contrastive Self-Supervised Learning

Technologies ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 2
Author(s):  
Ashish Jaiswal ◽  
Ashwin Ramesh Babu ◽  
Mohammad Zaki Zadeh ◽  
Debapriya Banerjee ◽  
Fillia Makedon
Keyword(s):  
Computer Vision ◽  
Supervised Learning ◽  
Language Processing ◽  
Large Scale ◽  
Performance Comparison ◽  
Extensive Review ◽  
Future Directions ◽  
Dominant Component ◽  
Supervised Methods ◽  
The Cost

Self-supervised learning has gained popularity because of its ability to avoid the cost of annotating large-scale datasets. It is capable of adopting self-defined pseudolabels as supervision and use the learned representations for several downstream tasks. Specifically, contrastive learning has recently become a dominant component in self-supervised learning for computer vision, natural language processing (NLP), and other domains. It aims at embedding augmented versions of the same sample close to each other while trying to push away embeddings from different samples. This paper provides an extensive review of self-supervised methods that follow the contrastive approach. The work explains commonly used pretext tasks in a contrastive learning setup, followed by different architectures that have been proposed so far. Next, we present a performance comparison of different methods for multiple downstream tasks such as image classification, object detection, and action recognition. Finally, we conclude with the limitations of the current methods and the need for further techniques and future directions to make meaningful progress.

scholarly journals A Review on Terahertz Technologies Accelerated by Silicon Photonics

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1646
Author(s):  
Jingya Xie ◽  
Wangcheng Ye ◽  
Linjie Zhou ◽  
Xuguang Guo ◽  
Xiaofei Zang ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Silicon Photonics ◽  
Large Scale ◽  
Cost Effective ◽  
Single Chip ◽  
Photonic Integrated Circuit ◽  
Hybrid Silicon ◽  
The Cost ◽  
Silicon Based ◽  
Thz Applications

In the last couple of decades, terahertz (THz) technologies, which lie in the frequency gap between the infrared and microwaves, have been greatly enhanced and investigated due to possible opportunities in a plethora of THz applications, such as imaging, security, and wireless communications. Photonics has led the way to the generation, modulation, and detection of THz waves such as the photomixing technique. In tandem with these investigations, researchers have been exploring ways to use silicon photonics technologies for THz applications to leverage the cost-effective large-scale fabrication and integration opportunities that it would enable. Although silicon photonics has enabled the implementation of a large number of optical components for practical use, for THz integrated systems, we still face several challenges associated with high-quality hybrid silicon lasers, conversion efficiency, device integration, and fabrication. This paper provides an overview of recent progress in THz technologies based on silicon photonics or hybrid silicon photonics, including THz generation, detection, phase modulation, intensity modulation, and passive components. As silicon-based electronic and photonic circuits are further approaching THz frequencies, one single chip with electronics, photonics, and THz functions seems inevitable, resulting in the ultimate dream of a THz electronic–photonic integrated circuit.

Network effect in shared supply chain platform value co-creation behavior in evolutionary game1

2021 ◽  
pp. 1-12
Author(s):  
Zou Xiaohong ◽  
Chen Jinlong ◽  
Gao Shuanping
Keyword(s):  
Boundary Condition ◽  
Supply Chain ◽  
Large Scale ◽  
Simulation Analysis ◽  
Supply And Demand ◽  
Evolutionary Game ◽  
Dynamic Game ◽  
Network Effect ◽  
Chain Model ◽  
The Cost

The shared supply chain model has provided new ideas for solving contradictions between supply and demand for large-scale standardized production by manufacturers and personalized demands of consumers. On the basis of a platform network effect perspective, this study constructs an evolutionary game model of value co-creation behavior for a shared supply chain platform and manufacturers, analyzes their evolutionary stable strategies, and uses numerical simulation analysis to further verify the model. The results revealed that the boundary condition for manufacturers to participate in value co-creation on a shared supply chain platform is that the net production cost of the manufacturers’ participation in the platform value co-creation must be less than that of nonparticipation. In addition, the boundary condition for the shared supply chain platform to actively participate in value co-creation is that the cost of the shared supply chain platform for active participation in value co-creation must be less than that of passive participation. Moreover, value co-creation behavior on the shared supply chain platform is a dynamic game interaction process between players with different benefit perceptions. Finally, the costs and benefits generated by the network effect can affect value co-creation on shared supply chain platforms.

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