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Journal articles on the topic 'Momentum of vehicles'
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1
Singh, S. N., L. Rai, P. Puri, and A. Bhatnagar. "Effect of moving surface on the aerodynamic drag of road vehicles." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 2 (February 1, 2005): 127–34. http://dx.doi.org/10.1243/095440705x5886.
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The effect on aerodynamic drag using a model of a truck has been investigated by controlling the boundary layer separation by the momentum injection method using a rotating cylinder. It involves the use of experiments coupled with computational fluid dynamics (CFD) analysis to validate the theory of momentum injection. Modelling of the truck has been done on the software GAMBIT©. The best suitable turbulence model was selected by comparing the results with the experimental results. The rotational speed and radius of the cylinder are varied to establish the effect of momentum injection on aerodynamic drag. The coefficient of drag reduces by approximately 35 per cent from an initial value of 0.51-0.32 for a cylinder of radius 1 cm with rotational speed of 4000 r/min.
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Vangi, Dario, Michelangelo-Santo Gulino, Anita Fiorentino, and Antonio Virga. "Crash momentum index and closing velocity as crash severity index." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 13 (January 17, 2019): 3318–26. http://dx.doi.org/10.1177/0954407018823658.
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The velocity change Δ V of a vehicle subject to a collision, widely recognized as an efficient crash severity indicator, is a typical ‘a posteriori’ parameter, not generally known until the crash phase has been reconstructed. Δ V is the result of a combination of factors, regarding the impact velocities of the colliding vehicles and the geometry of the impact (as eccentricity, etc.): for this reason, its value alone gives no clear indications on the actions which can be undertaken to reduce crash severity. This feature is particularly critical in some application fields, for example, in case of advanced driver assistance systems assessment in different accident scenarios. This work proposes the disaggregation of Δ V into two different ‘a priori’ parameters to assess crash severity of an impact before its occurrence: the crash momentum index, representing the impact configuration, and the closing velocity projected along the principal direction of force ( Vr_pdof), as an index of the kinetic energy exchanged between the two vehicles. It is preliminarily shown how the proposed parameters can be calculated using established procedures – as momentum-based analysis – in a predictive (‘a priori’) approach. It is also evidenced how crash momentum index, Vr_pdof and the velocity change Δ V are in relation. To illustrate the procedure by means of examples, binary logistic regression on accident data is applied to correlate crash momentum index and Δ V to injury risk at Maximum Abbreviated Injury Scale level higher than 2. The use of crash momentum index as an additional severity index allows an improved correlation with injury risk, for the dataset used, in case of front and near side impacts. The use of the plane Vr_pdof– crash momentum index, on which curves at constant injury risk are drawn, provides clear indications on the possible strategies to reduce injury risk, as shown by generic examples to which the predictive procedure is applied.
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Sun, Xiu Jun, Jian Shi, and Yan Yang. "Neural Networks Based Attitude Decoupling Control for AUV with X-Shaped Fins." Advanced Materials Research 819 (September 2013): 222–28. http://dx.doi.org/10.4028/www.scientific.net/amr.819.222.
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Attitude control in three-dimensional space for AUV (autonomous underwater vehicle) with x-shaped fins is complicated but advantageous. Yaw, pitch and roll angles of the vehicle are all associated with deflection angle of each fin while navigating underwater. In this paper, a spatial motion mathematic model of the vehicle is built by using theorem of momentum and angular momentum, and the hydrodynamic forces acting on x-shaped fins and three-blade propeller are investigated to clarify complex principle of the vehicle motion. In addition, the nonlinear dynamics equation which indicates the coupling relationship between attitude angles of vehicle and rotation angles of x-shaped fins is derived by detailed deduction. Moreover, a decoupling controller based on artificial neural networks is developed to address the coupling issue exposed in attitude control. The neural networks based controller periodically calculates and outputs deflection angles of fins according to the attitude angles measured with magnetic compass, thus the vehicles orientation can be maintained. By on-line training, twenty four weights in this controller converged according to index function.
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Grujicic, Mica, Brian d’Entremont, Jennifer Snipes, and S. Ramaswami. "A novel blast-mitigation concept for light tactical vehicles." International Journal of Numerical Methods for Heat & Fluid Flow 27, no. 4 (April 3, 2017): 889–923. http://dx.doi.org/10.1108/hff-12-2015-0502.
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Purpose A new concept solution for improving blast survivability of the light tactical military vehicles is proposed and critically assessed using computational engineering methods and tools. Design/methodology/approach The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called “pulse detonation” rocket engines, in particular, and is an extension of the recently introduced so-called “blast chimney” concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle). Relative to the blast-chimney concept, the new solution offers benefits since it does not compromise the cabin space or the ability of the vehicle occupants to scout the environment and, is not expected to, degrade the vehicle’s structural durability/reliability. The proposed concept utilizes side vent channels attached to the V-shaped vehicle underbody whose geometry is optimized with respect to the attainment of the maximum downward thrust on the vehicle. In the course of the channel design optimization, analytical and computational analyses of supersonic flow (analogous to the one often used in the case of the pulse detonation engine) are employed. Findings The preliminary results obtained reveal the beneficial effects of the side channels in reducing the blast momentum, although the extent of these effects is quite small (2-4 per cent). Originality/value To the authors’ knowledge, the present work is the first exploration of the side-vent-channels concept for mitigating the effect of buried-mine explosion on a light tactical vehicle.
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Grujicic, Mica, Ramin Yavari, Jennifer Snipes, and S. Ramaswami. "A combined finite-element/discrete-particle analysis of a side-vent-channel-based concept for improved blast-survivability of light tactical vehicles." International Journal of Structural Integrity 7, no. 1 (February 1, 2016): 106–41. http://dx.doi.org/10.1108/ijsi-12-2014-0068.
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Purpose – The recently proposed concept solution for improving blast-survivability of the light tactical military vehicles is critically assessed using combined finite-element/discrete-particle computational methods and tools. The purpose of this paper is to propose a concept that involves the use of side-vent-channels attached to the V-shaped vehicle underbody. Since the solution does not connect the bottom and the roof or pass through the cabin of a light tactical vehicle, this solution is not expected to: first, reduce the available cabin space; second, interfere with the vehicle occupants’ ability to scout the surroundings; and third, compromise the vehicle’s off-road structural durability/reliability. Furthermore, the concept solution attempts to exploit ideas and principles of operation of the so-called “pulse detonation” rocket engines in order to create a downward thrust on the targeted vehicle. Design/methodology/approach – To maximize the downward thrust effects and minimize the extent of vehicle upward movement, standard engineering-optimization methods and tools are employed for the design of side-vent-channels. Findings – The results obtained confirmed the beneficial effects of the side-vent-channels in reducing the blast momentum, although the extent of these effects is relatively small (3-4 percent). Originality/value – To the authors’ knowledge, the present work is the first public-domain report of the side-vent-channel blast-mitigation concept.
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Khan, Zuhaib Ashfaq, Hafiz Husnain Raza Sherazi, Mubashir Ali, Muhammad Ali Imran, Ikram Ur Rehman, and Prasun Chakrabarti. "Designing a Wind Energy Harvester for Connected Vehicles in Green Cities." Energies 14, no. 17 (August 31, 2021): 5408. http://dx.doi.org/10.3390/en14175408.
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Electric vehicles (EVs) have recently gained momentum as an integral part of the Internet of Vehicles (IoV) when authorities started expanding their low emission zones (LEZs) in an effort to build green cities with low carbon footprints. Energy is one of the key requirements of EVs, not only to support the smooth and sustainable operation of EVs, but also to ensure connectivity between the vehicle and the infrastructure in the critical times such as disaster recovery operation. In this context, renewable energy sources (such as wind energy) have an important role to play in the automobile sector towards designing energy-harvesting electric vehicles (EH-EV) to mitigate energy reliance on the national grid. In this article, a novel approach is presented to harness energy from a small-scale wind turbine due to vehicle mobility to support the communication primitives in electric vehicles which enable plenty of IoV use cases. The harvested power is then processed through a regulation circuitry to consequently achieve the desired power supply for the end load (i.e., battery or super capacitor). The suitable orientation for optimum conversion efficiency is proposed through ANSYS-based aerodynamics analysis. The voltage-induced by the DC generator is 35 V under the no-load condition while it is 25 V at a rated current of 6.9 A at full-load, yielding a supply of 100 W (on constant voltage) at a speed of 90 mph for nominal battery charging.
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Li, Yong, Xin Ge, and Xue Liang Hou. "The Research of Application Mode of Unmanned Aircraft Patrol in UHV Transmission Lines." Applied Mechanics and Materials 536-537 (April 2014): 989–92. http://dx.doi.org/10.4028/www.scientific.net/amm.536-537.989.
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In the UHV AC transmission lines will be rapid development momentum of main frame China grid, inspection of UHV transmission line for the realization of unmanned aircraft utility,this article makes an analysis for the structure characteristics and defects of the UHV transmission line , finds out the defect characteristics, and summarizes the characteristics of the UAV and inspection instrument. According to the characteristic of UHV defect, we display its properties of unmanned aerial vehicles and inspection instrument, construct the application mode of four kinds of unmanned aerial vehicle inspection, and have a description for each model.
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Gasanov, Badrudin, Artem Efimov, and Jurij Grebennikov. "RTA Mathematic Simulation Principles at the Autotechnical Expertise." MATEC Web of Conferences 334 (2021): 02026. http://dx.doi.org/10.1051/matecconf/202133402026.
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The features of carrying out an autotechnical expertise (ATE) are considered in case the vehicles (V) participating in the road transport accident (RTA) don’t leave skid imprints. The examples of momentum and energy conservation law application are given at developing the road accident mathematical model. Special attention is paid to the determination methods of vehicle (V) velocity, travel directions in various RTA diagrams and archeology of deformation. For this purpose it is offered to draw a momentum vector diagram. It is reasonable that for the calculation of V deformation at RTA it is necessary to determine step by step the strain-stress state in a contact area on the basis of the theories of elasticity, plasticity, solid friction and finite-element methods. The technique of constructing an RTA mathematical model is developed. It is recommended to use at ATE of RTAs at the runs-over into the fixed obstacle (a stationary V) and collisions.
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Wolf, Stefan, and Roman Korzynietz. "Innovation Needs for the Integration of Electric Vehicles into the Energy System." World Electric Vehicle Journal 10, no. 4 (November 12, 2019): 76. http://dx.doi.org/10.3390/wevj10040076.
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The mitigation of climate change and the substitution of fossil energy sources is one of the greatest tasks of our time. Electric mobility is the most promising solution to decarbonize the transport sector. As the market for electric vehicles is quickly gaining momentum, an urgent need for an intelligent integration of the energy and mobility system arises. This integration leads to a multitude of technical, economic and social challenges. Through a validated road-mapping process, the needs for future research, development, standardisation and regulation have been identified and visualised. Recommendations for action for decision-makers in politics and industry have been derived from those innovation needs. In summary, the most promising innovation path is the consequent application of smart and flexible charging concepts as well as an adaption of the regulations and roles in combination with the consequent usage of renewable energies. In five to ten years, also synergies through the exploitation of autonomous electric vehicles will gain momentum.
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Yang, Xiao Long, Ping Li, Tao Lv, and Xue Hua Liao. "Traffic Accident Reconstruction Technology Research." Advanced Materials Research 756-759 (September 2013): 946–51. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.946.
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Based on the virtual simulation theory, we used three-dimensional modeling software to build modeling road facilities (vehicles, trees, street lights, etc.) for simulating the accident environment, and by using OpenGL technology, achieved reading, displaying and controlling the three-dimensional models. This dynamically realized the three-dimensional animated simulation of vehicle movement. Simultaneously we have calculated in progress the simulation of vehicle crash with the basic theory of automobile collision, vehicle collision model and the law of conservation of energy and momentum. Finally, we constructed a flexible platform for the simulation experiment. The platform is enabling to add and update road, trees, street lamps and house on the simulation environment dynamically, and has ability to analysis the traffic accident. This could give an assistant to the handling traffic accidents.
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Yu, Yu Ting, Sheng Xiang, and Kenneth E. Noll. "Evaluation of the Relationship between Momentum Wakes behind Moving Vehicles and Dispersion of Vehicle Emissions Using Near-Roadway Measurements." Environmental Science & Technology 54, no. 17 (July 31, 2020): 10483–92. http://dx.doi.org/10.1021/acs.est.0c01587.
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Karapetkov, Stanimir, Lubomir Dimitrov, Hristo Uzunov, and Silvia Dechkova. "Identifying Vehicle and Collision Impact by Applying the Principle of Conservation of Mechanical Energy." Transport and Telecommunication Journal 20, no. 3 (June 1, 2019): 191–204. http://dx.doi.org/10.2478/ttj-2019-0016.
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Abstract Various methodologies and tools applied to identification of vehicle and collision impact seek to present more and more accurate solutions to reproduce, restore, recreate and investigate the casualty. Modern computer technology and software provide the tools to solve specific problems developing mathematical modelling of complex mechanical systems involving vehicles and other objects in a road accident. Scientists generally utilize the Standard Test Method for Impact Testing calculating the energy of deformation of both vehicles, however, one of its limitations is the evaluation of the kinetic energy of the vehicles in post-collision taking into consideration vehicle rotation and linear displacement. To improve the analysis, dynamic traffic simulation is used, taking into account the variations in the coefficient of friction, suspension elasticity and damping. The proposed method is based on a system of two equations derived from two principles: the Principle of Conservation of Mechanical Energy and the Principle of Conservation of Momentum in the impact phase. The new approach is conducted on mathematical modelling and computer simulation of vehicle motion after the impact, wherefrom the linear and angular velocities are analysed. This is achieved by the numerical solution of the differential equations of motion of the cars after the impact, and the given initial conditions that satisfy the solution are used to solve the system of equations. The main findings of the study can be grouped as follows: 1) The positions of the vehicles prior to the moment of first impact and the post-impact orientation of velocity vectors are more precise. 2) The variability of the tire-road friction coefficient is taken into consideration. 3) The value of coefficient of restitution according to Newton’s theory of impact is unnecessarily determined.
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Jung, Chanyoung, Daegyu Lee, Seungwook Lee, and David Hyunchul Shim. "V2X-Communication-Aided Autonomous Driving: System Design and Experimental Validation." Sensors 20, no. 10 (May 20, 2020): 2903. http://dx.doi.org/10.3390/s20102903.
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In recent years, research concerning autonomous driving has gained momentum to enhance road safety and traffic efficiency. Relevant concepts are being applied to the fields of perception, planning, and control of automated vehicles to leverage the advantages offered by the vehicle-to-everything (V2X) communication technology. This paper presents a V2X communication-aided autonomous driving system for vehicles. It is comprised of three subsystems: beyond line-of-sight (BLOS) perception, extended planning, and control. Specifically, the BLOS perception subsystem facilitates unlimited LOS environmental perception through data fusion between local perception using on-board sensors and communication perception via V2X. In the extended planning subsystem, various algorithms are presented regarding the route, velocity, and behavior planning to reflect real-time traffic information obtained utilizing V2X communication. To verify the results, the proposed system was integrated into a full-scale vehicle that participated in the 2019 Hyundai Autonomous Vehicle Competition held in K-city with the V2X infrastructure. Using the proposed system, the authors demonstrated successful completion of all assigned real-life-based missions, including emergency braking caused by a jaywalker, detouring around a construction site ahead, complying with traffic signals, collision avoidance, and yielding the ego-lane for an emergency vehicle. The findings of this study demonstrated the possibility of several potential applications of V2X communication with regard to autonomous driving systems.
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Kohnen, William. "MTS Manned Underwater Vehicles 2017‐2018 Global Industry Overview." Marine Technology Society Journal 52, no. 5 (September 1, 2018): 125–51. http://dx.doi.org/10.4031/mtsj.52.5.9.
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AbstractThe manned underwater vehicle industry continues to build momentum into 2018; much of this has been driven by strong market trends and technology. There is renewed growth in the luxury yachting industry, in citizen science, and in ocean philanthropy. Tourism submersibles offer high-end touring expeditions for boutique destinations and specialty cruise ships. In Asia, notably China, Japan, and India, deep-ocean science is gathering attention for research and commercial applications. The industry also benefits from an accepted use of lithium batteries by class societies and strong developments in the areas of navigation and communication technology. Finally, although military development typically focuses on unmanned capabilities, there is more investment in deep submergence submarine rescue vessels.
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Pei, Yu Long, Lian Zhen Wang, and Chuan Yun Fu. "Dynamics Model of Vehicle in Two-Dimensional Collision." Advanced Materials Research 446-449 (January 2012): 2646–49. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2646.
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The progress of vehicle collision can be broken into three stages: pre-collision, collision and post-collision. Although the direct collision lasts very little time, it is one of the most important stages of the whole process. On the basis of Momentum Conservation, Energy Conservation and improved Coefficient of Elastic Recovery, using Newtonian Mechanics, the paper constructs dynamics model for vehicles’ two-dimensional collisions, which can be used to calculate the velocities at the moments of before and after the collision. The paper uses the Software of PC-Crash as a comparative study, the results of which show that the proposed models are suitable for the analysis of collisions involving only two cars without second collision.
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Zhao, Fu Wen, and Bao Jian Zhao. "Research on the Development Strategies of New Energy Automotive Industry Based on Car Charging Stations." Applied Mechanics and Materials 740 (March 2015): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amm.740.985.
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The automotive industry is an important pillar industry of the national economy and plays an important role in the national economic and social development. With China's sustained and rapid economic development and urbanization accelerate, the future demand for a longer period of time the car will maintain the growth momentum, the resulting that energy shortage and environmental pollution problems will become more prominent. The emergence of new energy vehicles, can effectively alleviate the energy and environmental pressures, and to promote the sustainable development of the automobile industry, how to solve large-scale electric vehicle charging is a key factor, This paper analyzed the environmental impact from the vehicle, the number of charging stations and the distribution of key technical aspects, drawn to promote new energy vehicle technology innovation and rapid development, to maintain stable economic growth and improve people's living standards have an important strategic meaningful conclusions.
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Sanguesa, Julio A., Vicente Torres-Sanz, Piedad Garrido, Francisco J. Martinez, and Johann M. Marquez-Barja. "A Review on Electric Vehicles: Technologies and Challenges." Smart Cities 4, no. 1 (March 15, 2021): 372–404. http://dx.doi.org/10.3390/smartcities4010022.
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Electric Vehicles (EVs) are gaining momentum due to several factors, including the price reduction as well as the climate and environmental awareness. This paper reviews the advances of EVs regarding battery technology trends, charging methods, as well as new research challenges and open opportunities. More specifically, an analysis of the worldwide market situation of EVs and their future prospects is carried out. Given that one of the fundamental aspects in EVs is the battery, the paper presents a thorough review of the battery technologies—from the Lead-acid batteries to the Lithium-ion. Moreover, we review the different standards that are available for EVs charging process, as well as the power control and battery energy management proposals. Finally, we conclude our work by presenting our vision about what is expected in the near future within this field, as well as the research aspects that are still open for both industry and academic communities.
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Serré, Ronan, Hugo Fournier, and Jean-Marc Moschetta. "A design methodology for quiet and long endurance MAV rotors." International Journal of Micro Air Vehicles 11 (January 2019): 175682931984593. http://dx.doi.org/10.1177/1756829319845937.
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Over the last 10 years, the use of micro air vehicles has rapidly covered a broad range of civilian and military applications. While most missions require optimizing the endurance, a growing number of applications also require acoustic covertness. For rotorcraft micro air vehicles, combining endurance and covertness heavily relies on the capability to design new propulsion systems. The present paper aims at describing a complete methodology for designing quiet and efficient micro air vehicle rotors, ranging from preliminary aerodynamic prediction to aeroacoustic optimization to experimental validation. The present approach is suitable for engineering purposes and can be applied to any multirotor micro air vehicle. A fast-response and reliable aerodynamic design method based on the blade-element momentum theory has been used and coupled with an extended acoustic model based on the Ffowcs Williams and Hawkings equation as well as analytical formulations for broadband noise. The aerodynamic and acoustic solvers have been coupled within an optimization tool. Key design parameters include the number of blades, twist and chord distribution along the blade, as well as the choice of an optimal airfoil. An experimental test bench suitable for non-anechoic environment has been developed in order to assess the benefit of the new rotor designs. Optimal rotors can maintain high aerodynamic efficiency and low acoustic signature with noise reductions in the order of 10 dB(A).
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Bhatnagar, Kirti, and Abhishek Dr. "Effect of Rotor Blade Geometry on the Performance of Rotary-Winged Micro Air Vehicle." Defence Science Journal 66, no. 6 (October 31, 2016): 638. http://dx.doi.org/10.14429/dsj.66.9659.
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<p>The development of physics based analysis to predict the hover performance of a micro rotor system meant for a hover capable micro air vehicle for studying the role of blade geometric parameters (such as planform, twist etc.) is discussed. The analysis is developed using blade element theory using lookup table for the sectional airfoil properties taken from literature. The rotor induced inflow is obtained using blade element momentum theory. The use of taper seems beneficial in improving the hover efficiency for lower values of thrust coefficient. For rotors operating at high thrust conditions, high negative twist is desirable. There is no unique blade geometry which performs well under all thrust conditions. This well validated analysis can be used for design of hover capable micro air vehicles.</p>
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Keyworth, G. A. "Launch Vehicles of the Future: Earth to Near-Earth Space." International Astronomical Union Colloquium 123 (1990): 347–54. http://dx.doi.org/10.1017/s0252921100077277.
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None of us thought, when this colloquium was scheduled, that the timing would enable it to become a celebration as well. The launch, after years of postponements, of the Hubble Space Telescope, has cast a galactic glow over the proceedings here this week. But at the same time, the frustrating delays caused by the collapse in 1986 and very slow regeneration of the U.S. space launch capabilities since then make this discussion of near-earth access very pointed.As we know, the sheer momentum of the U.S. Space Shuttle Program has dominated our perceptions of space launch for a decade and a half. It reached its peak in the early 1980s when our national policy placed nearly total reliance on the Shuttle as our means of access to space. It was a policy doomed to fail, for obvious and not-so-obvious reasons.
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Zhu, Hang, Zihao Jiang, Hang Zhao, Siyu Pei, Hongze Li, and Yubin Lan. "Aerodynamic Performance of Propellers for Multirotor Unmanned Aerial Vehicles: Measurement, Analysis, and Experiment." Shock and Vibration 2021 (September 21, 2021): 1–11. http://dx.doi.org/10.1155/2021/9538647.
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Analyzing the propeller aerodynamic performance is of vital importance for research and improvement of unmanned aerial vehicles. This paper presents the design requirements for a propeller for rotorcraft unmanned aerial vehicles and an analysis of a model for calculating propeller aerodynamic performance. Based on blade element momentum theory, the aerodynamic force of a blade element is analyzed and used. The symmetric airfoil NACA 0012 is used as an example to verify the validity of the model. An experimental system for propeller aerodynamic performance is designed and built to test the aerodynamic performance of six types of the propeller from a single manufacturer (APC). Data-processing software is also developed to draw curves and perform single-step calculations of three propellers’ parameters: airfoil resistance power, induced velocity, and efficiency. The results of the experiment indicate that both the thrust and torque of the propeller increase with rotational speed, propeller diameter, and propeller pitch. The research is of great significance to select more suitable propellers for unmanned aerial vehicles and the further improvement of the performance of unmanned aerial vehicles’ dynamical system.
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Thiel, Christian, Anastasios Tsakalidis, and Arnulf Jäger-Waldau. "Will Electric Vehicles Be Killed (again) or Are They the Next Mobility Killer App?" Energies 13, no. 7 (April 10, 2020): 1828. http://dx.doi.org/10.3390/en13071828.
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Electric vehicles (EVs) have been around for more than a hundred years. Nevertheless, their deployment has not been a sustainable success up until now. Many scientists, engineers and policymakers argue that EVs are a promising, maybe even indispensable option to achieve ambitious decarbonization goals, if powered by electricity from renewable energy sources. At the moment, the EVs market is gaining a lot of momentum and we may be near the point of no return for a sustained mass market deployment of electric vehicles. Many papers exist that describe future prospects of EVs. In our commentary we try to provide a bigger picture view and look at market and societal aspects. We analyze why previous generations of EVs were not successful and how current electric vehicles could become a sustainable success. We perform a semi-quantitative Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis and find that current electric vehicle designs are technologically on par with or better than conventional alternatives. Car buyers go electric when the economics make sense to them. We conclude that incentives are needed for electric vehicles until battery costs lower—as much as to allow EVs to become cheaper—from a total cost of ownership (TCO) perspective, than other alternatives. Other policy measures are needed to overcome remaining barriers, especially in supporting the setup and operation of publicly accessible recharging points to overcome range anxiety. EVs in isolation may not be the next mobility killer app. The real next mobility killer app may emerge as an autonomous shared EV in a world where the border between public and private transport will cease to exist. The findings of our commentary are relevant for scientists, policymakers and industry.
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Costello, John H., Sean P. Colin, Brad J. Gemmell, and John O. Dabiri. "Hydrodynamics of Vortex Generation during Bell Contraction by the Hydromedusa Eutonina indicans (Romanes, 1876)." Biomimetics 4, no. 3 (July 5, 2019): 44. http://dx.doi.org/10.3390/biomimetics4030044.
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Swimming bell kinematics and hydrodynamic wake structures were documented during multiple pulsation cycles of a Eutonina indicans (Romanes, 1876) medusa swimming in a predominantly linear path. Bell contractions produced pairs of vortex rings with opposite rotational sense. Analyses of the momentum flux in these wake structures demonstrated that vortex dynamics related directly to variations in the medusa swimming speed. Furthermore, a bulk of the momentum flux in the wake was concentrated spatially at the interfaces between oppositely rotating vortices rings. Similar thrust-producing wake structures have been described in models of fish swimming, which posit vortex rings as vehicles for energy transport from locations of body bending to regions where interacting pairs of opposite-sign vortex rings accelerate the flow into linear propulsive jets. These findings support efforts toward soft robotic biomimetic propulsion.
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Othman, Zuraini, Asmala Ahmad, Fauziah Kasmin, Sharifah Sakinah Syed Ahmad, Mohd Yazid Abu Sari, and Muhammad Amin Mustapha. "Comparison between Edge Detection Methods on UTeM Unmanned Arial Vehicles Images." MATEC Web of Conferences 150 (2018): 06029. http://dx.doi.org/10.1051/matecconf/201815006029.
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Machine vision calls for the use of detectors to ascertain the features and type of object portrayed in the image. The employment of unmanned aerial vehicles (UAVs), which can function freely in active and precarious settings, is currently gaining momentum. These vehicles are mainly used for the detecting, classifying and tracking of an object. However, the achievement of these objectives necessitates the involvement of an effective edge detection procedure. Sobel, Canny, Prewitt and LoG are among the many edge detection procedures presently available. In this endeavour, we opted for the utilization of UTeM UAVs images for an evaluation of these edge detection procedures. During our investigations, the ground truth edge images were corroborated by a specialist in this field. The results obtained from these investigations revealed that in terms of accuracy, precision, sensitivity and f-measure, the Prewitt procedure outperforms the other methods mentioned.
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Barnard, J. H. "An analysis of the friction mechanism on brake gear of railway rolling stock." Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 4, no. 4 (March 18, 1985): 171–80. http://dx.doi.org/10.4102/satnt.v4i4.1055.
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Friction energy dissipation at an interface involves a wide range of interdisciplinary concepts. As the demand for higher operating speeds increased, the limitations of cast iron as the traditional friction material for rail transport brakes became more apparent. Only through an intensive analysis of the interfacial interaction between the brake block and brake path could the problems encountered with other promising friction materials be solved. The article deals with the difficulties pertaining to the early composite materials, and indicates how these were overcome by the understanding and implementation of new techniques not previously associated with conventional systems connected with railway braking. Two composite materials, that is 840/N for locomotives and freight wagons where mass oriented momentum dominates, and high friction composite 655/C for passenger vehicles with a predominantly speed-oriented momentum, are presently used.
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Santa, José, Ramon Sanchez-Iborra, Pablo Rodriguez-Rey, Luis Bernal-Escobedo, and Antonio Skarmeta. "LPWAN-Based Vehicular Monitoring Platform with a Generic IP Network Interface." Sensors 19, no. 2 (January 11, 2019): 264. http://dx.doi.org/10.3390/s19020264.
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Remote vehicle monitoring is a field that has recently attracted the attention of both academia and industry. With the dawn of the Internet of Things (IoT) paradigm, the possibilities for performing this task have multiplied, due to the emergence of low-cost and multi-purpose monitoring devices and the evolution of wireless transmission technologies. Low Power-Wide Area Network (LPWAN) encompasses a set of IoT communication technologies that are gaining momentum, due to their highly valued features regarding transmission distance and end-device energy consumption. For that reason, in this work we present a vehicular monitoring platform enabled by LPWAN-based technology, namely Long Range Wide Area Network (LoRaWAN). Concretely, we explore the end-to-end architecture considering vehicle data retrieving by using an On-Board Diagnostics II (OBD-II) interface, their compression with a novel IETF compression scheme in order to transmit them over the constrained LoRaWAN link, and information visualization through a data server hosted in the cloud, by means of a web-based dashboard. A key advance of the proposal is the design and development of a UNIX-based network interface for LPWAN communications. The whole system has been tested in a university campus environment, showing its capabilities to remotely track vehicle status in real-time. The conducted performance evaluation also shows high levels of reliability in the transmission link, with packet delivery ratios over 95%. The platform boosts the process of monitoring vehicles, enabling a variety of services such as mechanical failure prediction and detection, fleet management, and traffic monitoring, and is extensible to light vehicles with severe power constraints.
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Rada, Roy. "Filtering the piotroski portfolio: the roles of economic sector, small cap, and technical momentum." International Journal of Accounting and Economics Studies 3, no. 1 (March 23, 2015): 44. http://dx.doi.org/10.14419/ijaes.v3i1.4371.
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<p>Background and Objective: In one of the most cited, value-investing results, a portfolio of approximately 100 stocks is selected based on value and fundamental factors. If an investor wants to select 10 of those recommended stocks, then to what extent might economic sector diversification, market capitalization, and technical momentum indicators be useful?</p><p>Method and Results: In this paper, several strategies produce the 10-stock portfolio that retains the performance of the 100-stock portfolio. Choosing the smallest market cap stocks tends to make the greatest, positive difference in gains, but deeper investigation reveals that those stocks may not be practically accessible investment vehicles.</p>
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Kuhns, Hampden, John Gillies, Vicken Etyemezian, George Nikolich, James King, Dongzi Zhu, Sebastian Uppapalli, Johann Engelbrecht, and Steve Kohl. "Effect of Soil Type and Momentum on Unpaved Road Particulate Matter Emissions from Wheeled and Tracked Vehicles." Aerosol Science and Technology 44, no. 3 (February 10, 2010): 187–96. http://dx.doi.org/10.1080/02786820903516844.
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gupta, Akash, Rahat Ali, Abhay Pratap Singh, and P. Raja Kumar. "Autonomous Recognition Model." International Journal of Innovative Technology and Exploring Engineering 10, no. 6 (April 30, 2021): 67–73. http://dx.doi.org/10.35940/ijitee.f8821.0410621.
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Nowdays we are witnessing the technology transforming everything the way we used to do things and how the automobile industry is transforming itself with the use of technology IOT,Artificial intelligence,Machine learning.Companies shifting its products and its utilities in diferent way and they now want to acquire and introduce level-5 autonomous to future generation and big automobile companies are trying to achieve autonomous vechicles and we have researhed about the model that will help in assisting autonomous vechicles and trying to achieve that.We will develop this model with help of technologies like Artificial intelligence,Machine learning,Deep learning.Autonomous vehcicles will become a reality on our roads in the near future. However, the absence of a human driver requires technical solutions for a range of issues, and these are still being developed and optimised. It is a great contribution for the automotive industry which is going towards innovation and economic growth. If we talking about some past decade the momentum of new research and the world is now at the very advanced stage of technological revolution. “Autonomous-driving” vehicles. The term Self-driving cars, autonomous car, or the driverless cars have different name with common objective. The main focus is to keep the human being out of the vehicle control loop and to relieve them from the task of driving. Everyday automotive technology researchers solve challenges. In the future, without human assistance, robots will produce autonomous vehicles using IoT technology based on customer needs and prefer that these vehicles are more secure and comfortable in mobility systems such as the movement of people or goods. We will build a deep neural network model that can classify traffic signs present in the image into different categories. With this model, we are able to read and understand traffic signs which are a very important task for all autonomous vehicles .This model we have tested it and resulted in 95% accuracy.
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Mohd Zawawi, Fazila, Peng Lv, Sebastien Prothin, Joseph Morlier, Emmanuel Benard, and Jean Marc Moschetta. "Performance Enhancement of Tilt-Body Micro Air Vehicle by Use of Orthotropic Laminated Proprotors." Applied Mechanics and Materials 819 (January 2016): 585–90. http://dx.doi.org/10.4028/www.scientific.net/amm.819.585.
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A passive twist control is considered as an adaptive way to maximize the overall efficiency of a proprotor developed for convertible Micro Air Vehicles (MAV). In this paper, adaptation of the proprotor geometry in accordance to flight configurations is achieved by induced twist generated by the inherent structural coupling effect in anisotropic composite material and centrifugal force emanating from the tip load. Beam Finite Element Model based on Rotating Timoshenko Theory is used to predict structural loads, while Blade Element Momentum Theory is employed to predict the aerodynamic performance of adaptive proprotor as applied on Micro Air Vehicles (MAV). The iterative process of combination of aerodynamic model and structural model is used to compute the steady-state deformation of the flexible laminated proprotor blade due aerodynamic loads. Finally, the optimal design of lamina blade material is carried out to investigate the potential of flexible blade in the proprotorperformance enhancement.
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Gettman, Douglas, and Larry Head. "Surrogate Safety Measures from Traffic Simulation Models." Transportation Research Record: Journal of the Transportation Research Board 1840, no. 1 (January 2003): 104–15. http://dx.doi.org/10.3141/1840-12.
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Safety is emerging as an area of increased attention and awareness within transportation engineering. Historically, the safety of new and innovative traffic treatments has been difficult to assess, primarily because of a lack of good predictive models of crash potential and a lack of consensus on what constitutes a safe or unsafe facility. An FHWA-sponsored research project investigated the potential to derive surrogate measures of safety from existing traffic simulation models. These surrogate measures could then be used to support evaluations of various traffic engineering alternatives, including facilities that have not yet been built and strategies that have not yet been used. Each surrogate measure is collected on the basis of the occurrence of a conflict event, which is an interaction between two vehicles in which one vehicle must take evasive action to avoid a collision. The surrogate measures that are proposed as the best are time to collision, postencroachment time, deceleration rate, maximum speed, and speed differential. Time to collision, postencroachment time, and deceleration rate can be used to measure the severity of the conflict. Maximum speed and the speed differential can be used to measure the severity of the potential collision (by use of additional information about the mass of the vehicles involved to assess momentum). After the simulation model is executed for a number of iterations, a postprocessing tool would be used to compute the statistics for the various measures and perform comparisons between design alternatives.
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Matcha, Bhargav Naidu, Satesh Narayana Namasivayam, Mohammad Hosseini Fouladi, K. C. Ng, Sivakumar Sivanesan, and Se Yong Eh Noum. "Simulation Strategies for Mixed Traffic Conditions: A Review of Car-Following Models and Simulation Frameworks." Journal of Engineering 2020 (January 25, 2020): 1–22. http://dx.doi.org/10.1155/2020/8231930.
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The area of traffic flow modelling and analysis that bridges civil engineering, computer science, and mathematics has gained significant momentum in the urban areas due to increasing vehicular population causing traffic congestion and accidents. Notably, the existence of mixed traffic conditions has been proven to be a significant contributor to road accidents and congestion. The interaction of vehicles takes place in both lateral and longitudinal directions, giving rise to a two-dimensional (2D) traffic behaviour. This behaviour contradicts with the traditional car-following (CF) or one-dimensional (1D) lane-based traffic flow. Existing one-dimensional CF models did the inclusion of lane changing and overtaking behaviour of the mixed traffic stream with specific alterations. However, these parameters cannot describe the continuous lateral manoeuvre of mixed traffic flow. This review focuses on all the significant contributions made by 2D models in evaluating the lateral and longitudinal vehicle behaviour simultaneously. The accommodation of vehicle heterogeneity into the car-following models (homogeneous traffic models) is discussed in detail, along with their shortcomings and research gaps. Also, the review of commercially existing microscopic traffic simulation frameworks built to evaluate real-world traffic scenario are presented. This review identified various vehicle parameters adopted by existing CF models and whether the current 2D traffic models developed from CF models effectively captured the vehicle behaviour in mixed traffic conditions. Findings of this study are outlined at the end.
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Yu, Pengfei, Zihao Wang, and KC Wong. "Exploring aerial perching and grasping with dual symmetric manipulators and compliant end-effectors." International Journal of Micro Air Vehicles 11 (January 2019): 175682931987741. http://dx.doi.org/10.1177/1756829319877416.
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Inspired by talon of a predator bird, this paper presents a quadrotor with two 2- Degree of Freedoms (DOFs) compliant manipulators which could mimic bird perching and grasping. The symmetric configuration of the manipulators causes minimum shift in center of gravity and a minimum disturbance to the angular momentum of the platform during grasping and perching maneuvers. Thus, the dynamics of the manipulator is independent to that of the platform. Moreover, a compliant end-effector is introduced to decouple the dynamics of the unmanned aerial vehicles from the force interaction with the environment or target objects. Therefore, aerial manipulation problem is significantly simplified due to the minimum amount of disturbance among components. In addition, the manipulators could function as the landing gear, which allows larger work envelope, weight saving and less landing impact. It also has the potential to achieve a bird-like “perch and watch” to increase the endurance of unmanned aerial vehicles in missions that involve extended endurance.
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Gönczi, Attila Iuliu, Adrian Cipleu, and Liviu Mihon. "Reconstruction of an Unusual Road Traffic Accident Using Two Different Versions of a Simulation Program." Applied Mechanics and Materials 822 (January 2016): 503–11. http://dx.doi.org/10.4028/www.scientific.net/amm.822.503.
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In most of the cases of a road traffic accident reconstruction, the usage of traditional reconstruction methods represents the basic set of tools, but in an ever increasing number of cases, computer simulation is used for control the results or vice versa. In some cases, traditional methods, based on linear momentum conservation, energy conservation and assessment of deformation of the vehicles or experimental results of crash tests are not suitable because of the highly unusual character of the collision. The paper deals with one case of this type in which the pedestrian was cut in two parts.
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Ramanujam, Padmapriya, Saravanan Poorni, Manali Ramakrishnan Srinivasan, and Nivedhitha Malli Sureshbabu. "Probiotics in Dental Caries Prevention." Indian Journal of Nutrition and Dietetics 56, no. 1 (January 22, 2019): 84. http://dx.doi.org/10.21048/ijnd.2019.56.1.22609.
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The prevalence of oral diseases is increasing and is becoming a major concern in the society. Treatment without prevention is simply unsustainable. One such preventable disease is dental caries. Several strategies for caries prevention have been developed over the years. Bacteriotherapy is one potential method. With better understanding on the importance of a well balanced oral microbial environment for maintaining good dental health, probiotics has gained great momentum in dentistry. The World Health Organization along with the Food and Agriculture Organisation of the United Nations defined probiotics as “Live microorganisms which when administered in adequate amounts confer a health benefit on the host”. Several probiotic strains have been identified for caries prevention through various experimental studies. However, identifying the right vehicle for administration of probiotics on everyday basis is the need of the hour. Toothpastes, mouthrinses, powders, tablets, lozenges, chewing gums are some probiotic vehicles that have been studied. This paper would throw light on the microbial strains, mechanism of action, forms and future for probiotics in caries prevention.
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Du, Xianbin, Youqun Zhao, Yijiang Ma, and Hongxun Fu. "Influence of hinge length and distribution number on the camber and cornering properties of a non-pneumatic tire." Advances in Mechanical Engineering 12, no. 12 (December 2020): 168781402098468. http://dx.doi.org/10.1177/1687814020984687.
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The camber and cornering properties of the tire directly affect the handling stability of vehicles, especially in emergencies such as high-speed cornering and obstacle avoidance. The structural and load-bearing mode of non-pneumatic mechanical elastic (ME) wheel determine that the mechanical properties of ME wheel will change when different combinations of hinge length and distribution number are adopted. The camber and cornering properties of ME wheel with different hinge lengths and distributions were studied by combining finite element method (FEM) with neural network theory. A ME wheel back propagation (BP) neural network model was established, and the additional momentum method and adaptive learning rate method were utilized to improve BP algorithm. The learning ability and generalization ability of the network model were verified by comparing the output values with the actual input values. The camber and cornering properties of ME wheel were analyzed when the hinge length and distribution changed. The results showed the variation of lateral force and aligning torque of different wheel structures under the combined conditions, and also provided guidance for the matching of wheel and vehicle performance.
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Brandner, Paul, and Martin Renilson. "Interaction Between Two Closely Spaced Azimuthing Thrusters." Journal of Ship Research 42, no. 01 (March 1, 1998): 15–32. http://dx.doi.org/10.5957/jsr.1998.42.1.15.
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To assist in predicting the performance of omni-directional propelled vehicles a series of experiments has been conducted to measure the interaction between two closely spaced ductedazimuthing thrusters. The thrusters were tested below a shallow draft ground board in a towing tank at a spacing of approximately 2 propeller diameters. Measurements were made of forces acting on a single thruster for a range of operating conditions and similarly on two thrusters for a range of relative positions. The results show that forces from the trailing thruster are heavily affected by interaction, particularly due to impingement of the race from the leading thruster, where as forces from the leading thruster remain essentially unaffected despite its proximity to the trailing thruster. A semi-empirical mathematical model suitable for simulation of omni-directional vehicle dynamics is presented. The model is based on the trajectory of the race from the leading thruster derived from momentum considerations with additional empirical relations to account for other more minor flow effects. Comparison of the predicted and measured results show satisfactory agreement.
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Mabrouk, Elmehdi. "Assessing the Impact of Electric Vehicle Fleets on a Multi-Microgrids System Under Different Operating Modes." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 5 (April 11, 2021): 1000–1014. http://dx.doi.org/10.17762/turcomat.v12i5.1744.
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The Global climate change and the lack of fossil fuels reserves have already had observable effects on the environment. Therefore, an undeniable investment is being made to respond these heavy challenges and to accelerate the momentum towards further embracing the electrification of transportation in smart microgrids, energy efficiency and clean energy production. The paper presents a novel cost-effective management of non-renewable resources of a multi-microgrid system under different operating modes (islanded, connected) with integrating renewable energy sources. Also, we investigate the impact of controlling vehicle-to-grid (V2G) operations on the multi-microgrid system by establishing a coordinated charging control strategy for plug-in electric vehicles (PEVs) with the aim of obtaining the maximum benefit from the grid as well as minimize the overall operating cost of the system. Both, the management of the multi-microgrid system and the EVs charging strategy have been formulated and solved using the Genetic Algorithm (GA), where the obtained results have shown that this method increases the quality, and the efficiency of obtained day-ahead scheduling solutions under any operating mode.
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Prakash, Jitendra. "Biogas and Biodiesel: Fuels for the New Millennium." Ushus - Journal of Business Management 1, no. 1 (January 1, 2002): 46–56. http://dx.doi.org/10.12725/ujbm.1.7.
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The rapid depletion of fossil fuels and their adverse effect on the environment have led scientists to look for alternative sources and technologies of energy production. India took the lead in utilising biological wastes for the production of 'biogas' with varied applications like cooking and power generation. South Africa first used transesterified vegetable oil as 'biodiesel' to power vehicles. With the numerous benefits to mankind and environment, the use of biological fuels is gaining momentum throughout the world. With a little more streamlining, biofuels will be soon replacing the existing fuel sources, at the same time helping us to rectify the thoughtless exploitation of the past.
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TAŞ, Elif Nur, Zeynep PARALI, and Hatice Nur ÇETİN. "DÜNYA BASININDA TÜRKİ YE’Nİ N S/İ HA GÜCÜ VE KÜRESEL Sİ YASETE YANSIMALARI." “Küresel siyaset: Türkiye’den bakış”, Spring,2021 (April 30, 2021): 202–29. http://dx.doi.org/10.30546/2616-4418.bitd.2021.202.
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Technological innovations in the ield of informatics, rapid developments in subjects such as artiicial intelligence and robotic engineering have put Unmanned Aerial Vehicles (UAV) and Armed Unmanned Aerial Vehicles (UCAV) into the battleield of the 21st century. At this point, states whose common concerns are security have taken the path of both obtaining intelligence and developing unmanned aerial systems, whose use is rapidly increasing in the ield of war-defense. It is known that many countries are currently working on developing and producing UAVs, beside United States of America (USA) and Israel which both have advanced unmanned aerial systems. Because states that are developing and manufacturing their own unmanned aerial systems are aware that this situation will provide a strategic advantage in terms of their military, political and economic interests. In this context, Turkey didn’t stay indifferent to the developments of unmanned aerial systems emerging in each passing day, it has made considerable momentum towards the last ifteen years to develop national and indigenous UAV systems. Especially since mid-2010, these systems have been used eficiently in both intra border operations and crossborder operations The main question of this article is how Turkey’s UAV/UCAV power is relected in global politics and in this direction, world press will be scanned. In this context, this study will primarily explained by Turkey’s domestic and national development of unmanned aerial systems adventure in general terms; then Turkey’s use of these vehicles in where and for what purpose will be evaluated. Afterward it will be evaluated that how Turkey’s power of UAV/UCAV is perceived by other states in economic and military-political aspects by examining the relevant state press and publishing organizations Keywords: Turkey, Unmanned Aerial Vehicles, Unmanned Combat Aerial Vehicles, Press- Publishing Organizations.
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Balike, M., S. Rakheja, and S. V. Hoa. "STUDY OF AN ENERGY DISSIPATING UNDER-RIDE GUARD USING HARDWARE-IN-THE-LOOP SIMULATION." Transactions of the Canadian Society for Mechanical Engineering 23, no. 2 (June 1999): 307–20. http://dx.doi.org/10.1139/tcsme-1999-0021.
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Hardware-in-the-Loop (HIL) simulation technique is implemented to analyze the performance characteristics of an energy dissipative under-ride guard system for enhancement of crashworthiness of lightweight vehicles involved in coillisions with heavy freight vehicles. The experimental setup, software and hardware interface, and the test methodology used to perform the HIL simulation are briefly described. The energy dissipating under-ride guard, while impacted by a car body, is analytically modeled incorporating nonlinearities due to asymmetric damping in compression and rebound, restoring properties and kinematics of linkages, using the principles of conservation of momentum and Lagrangian dynamics. The performance characteristics of the under-ride guard are evaluated under direct impact at different speeds, and the results obtained from the HIL simulation are compared with those derived from the nonlinear analytical model. The study revealed very good correlation between the analytical and experimental findings in terms of the amount of energy dissipated, acceleration level, rebound velocity and the magnitude of intrusion. An analysis of the results showed that significant portion of the kinetic energy can be dissipated by the under-ride guard.
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MacNeill, R., and D. Verstraete. "Blade element momentum theory extended to model low Reynolds number propeller performance." Aeronautical Journal 121, no. 1240 (May 3, 2017): 835–57. http://dx.doi.org/10.1017/aer.2017.32.
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ABSTRACTPropellers are the predominant propulsion source for small unmanned aerial vehicles. At low advance ratios, large sections of the propeller blade can be stalled, and the Reynolds number faced by each blade can be low. This leads to difficulties in modelling propeller performance, as the aerodynamic models coupled with blade element methods usually only provide aerodynamic data for an assumed aerofoil section, for a small angle-of-attack range and for a single Reynolds number, while rotational effects are often ignored. This is specifically important at low advance ratios, and a consistent evaluation of the applicability of various methods to improve aerodynamic modelling is not available. To provide a systematic appraisal, three-dimensional (3D) scanning is used to obtain the aerofoil sections that make up a propeller blade. An aerodynamic database is formed using each extracted aerofoil section, across a wide range of angles of attack and Reynolds numbers. These databases are then modified to include the effects of rotation. When compared with experimental results, significant improvement in modelling accuracy is shown at low advance ratios relative to a generic blade element-momentum model, particularly for smaller propellers. Notably, when considering small propeller performance, efficiency modelling is improved from within 30% relative to experimental data to within 5% with the use of the extended blade element momentum theory method. The results show that combining Viterna and Corrigan flat plate theory with the Corrigan and Schillings stall delay model consistently yields the closest match with experimental data.
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Chivukula, Venkata Kalyan, and M. V. Aditya Nag. "Comparative Analysis on Characteristics of Gasoline & Gasoline Methanol Blend." Advanced Materials Research 588-589 (November 2012): 111–14. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.111.
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Researchers, environmentalists, and policy makers are keen to reduce the dependency on use of fossil fuels towards climate change. Various alternatives are being implemented for alternate sources of energy for transportation sector; Biofuels can reduce the dependency on the import of the fossil fuels. Different kind of biofuels are available compositions are alcohols, ethers, esters etc. Commonly available biofuels are ethanol, methanol and biodiesel. They can be produced from various thermo-chemical and bio-chemical processes. Methanol has been gaining momentum as a potential alternative for traditional fossil fuels in transportation sector. There is an increased trend in the development of methanol as a fuel around the world. This paper deals with the study of the use of methanol as an automotive fuel. Methanol has certain positive properties on the vehicle’s performance. However, methanol cannot be used directly as a fuel in the vehicles due to volatility and compatibility issues. But it could be used as a blend with the gasoline for its characteristics such as high octane number and lower emissions. Blending of methanol with gasoline will have affect on the properties of blend, this paper discusses about the change in properties and its effects on engine.
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Chan, Keen Ian. "Generalized Aerodynamic Optimization of Hovering Coaxial Rotor Blades." Journal of the American Helicopter Society 64, no. 2 (April 1, 2019): 1–13. http://dx.doi.org/10.4050/jahs.64.022006.
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This paper presents the development and application of a generalized approach to the aerodynamic optimization of hovering coaxial rotors. The generalization lifts the constraints of previous theories and enables dissimilar rotor diameters, dissimilar rotational speeds, and thrust-sharing percentage of the upper and lower rotors of a coaxial pair to be incorporated as design variables. This increased versatility was necessitated by the emergence of electric vertical take-off and landing unmanned aerial vehicles, which feature independently driven rotors and have unique operational requirements. The optimization methodology begins with the derivation of the generalized momentum theory for coaxial rotors, and then extending the formulation to become an optimization technique, which determines optimal combinations of rotor diameters and rotational speeds for a specified thrust-sharing percentage. These results are next used as inputs to determine the optimal dissimilar geometries for the upper and lower rotor blades. The optimization is demonstrated on a multirotor vertical take-off and landing unmanned aerial vehicle with three coaxial pairs of rotors. The results show that a high figure of merit is achieved, and this is a contributing factor in improved hover endurance.
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Tang, Wei, and Bi-Feng Song. "Transitional flight equilibrium and performance study for the X-NMRL tail-sitter VTOL MAV." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 8 (August 19, 2018): 3056–77. http://dx.doi.org/10.1177/0954410018794731.
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An investigation on transitional flight equilibrium, performance analysis and parameter impacts is conducted in a conversion corridor, based on the proposed X-NMRL tail-sitter Vertical Takeoff and Landing Micro Air Vehicles (VTOL MAVs). Dependent on a propulsion model, aerodynamic model and physical control model, a nonlinear mathematical transitional model of the vehicle dynamics was constructed with consideration of the velocity, angle of attack, thrust, control surface deflection and pitching angle. The momentum theory and estimation method are applied to simulated propeller slipstream effects on aerodynamics, and an aerodynamic model for all regions of angles of attack and velocities is built. The nonlinear indefinite high-order dynamic model is solved by the improved Newton iteration algorithm. The corridor of the pitching angle or flight-path angle to the velocity reveals that the boundaries are mainly governed by the stalling performance, full throttle thrust and zero thrust, respectively. The performance corridor indicates different performance parameter variations under different conditions of steady climbing, cruising and descending states. Additionally, the performance for a steady transitional strategy can be illustrated to some extent. In terms of the parameter impacts, the increasing max propulsive power, supplied voltage, and decreasing total weight can widen the transitional corridor effectively, and the changes in the aerodynamics will only move the boundaries toward the same direction. These results will benefit transitional vehicle designs and control designs.
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Reineman, Benjamin D., Luc Lenain, Nicholas M. Statom, and W. Kendall Melville. "Development and Testing of Instrumentation for UAV-Based Flux Measurements within Terrestrial and Marine Atmospheric Boundary Layers." Journal of Atmospheric and Oceanic Technology 30, no. 7 (July 1, 2013): 1295–319. http://dx.doi.org/10.1175/jtech-d-12-00176.1.
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Abstract Instrumentation packages have been developed for small (18–28 kg) unmanned aerial vehicles (UAVs) to measure momentum fluxes as well as latent, sensible, and radiative heat fluxes in the atmospheric boundary layer (ABL) and the topography below. Fast-response turbulence, hygrometer, and temperature probes permit turbulent momentum and heat flux measurements, and shortwave and longwave radiometers allow the determination of net radiation, surface temperature, and albedo. UAVs flying in vertical formation allow the direct measurement of fluxes within the ABL and, with onboard high-resolution visible and infrared video and laser altimetry, simultaneous observation of surface topography or ocean surface waves. The low altitude required for accurate flux measurements (typically assumed to be 30 m) is below the typical safety limit of manned research aircraft; however, with advances in laser altimeters, small-aircraft flight control, and real-time kinematic differential GPS, low-altitude flight is now within the capability of small UAV platforms. Flight tests of instrumented BAE Systems Manta C1 UAVs over land were conducted in January 2011 at McMillan Airfield (Camp Roberts, California). Flight tests of similarly instrumented Boeing Insitu ScanEagle UAVs were conducted in April 2012 at the Naval Surface Warfare Center, Dahlgren Division (Dahlgren, Virginia), where the first known measurements of water vapor, heat, and momentum fluxes were made from low-altitude (down to 30 m) UAV flights over water (Potomac River). This study presents a description of the instrumentation, summarizes results from flight tests, and discusses potential applications of these UAVs for (marine) atmospheric boundary layer studies.
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Gaffey, Clare, and Anshuman Bhardwaj. "Applications of Unmanned Aerial Vehicles in Cryosphere: Latest Advances and Prospects." Remote Sensing 12, no. 6 (March 15, 2020): 948. http://dx.doi.org/10.3390/rs12060948.
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Owing to usual logistic hardships related to field-based cryospheric research, remote sensing has played a significant role in understanding the frozen components of the Earth system. Conventional spaceborne or airborne remote sensing platforms have their own merits and limitations. Unmanned aerial vehicles (UAVs) have emerged as a viable and inexpensive option for studying the cryospheric components at unprecedented spatiotemporal resolutions. UAVs are adaptable to various cryospheric research needs in terms of providing flexibility with data acquisition windows, revisits, data/sensor types (multispectral, hyperspectral, microwave, thermal/night imaging, Light Detection and Ranging (LiDAR), and photogrammetric stereos), viewing angles, flying altitudes, and overlap dimensions. Thus, UAVs have the potential to act as a bridging remote sensing platform between spatially discrete in situ observations and spatially continuous but coarser and costlier spaceborne or conventional airborne remote sensing. In recent years, a number of studies using UAVs for cryospheric research have been published. However, a holistic review discussing the methodological advancements, hardware and software improvements, results, and future prospects of such cryospheric studies is completely missing. In the present scenario of rapidly changing global and regional climate, studying cryospheric changes using UAVs is bound to gain further momentum and future studies will benefit from a balanced review on this topic. Our review covers the most recent applications of UAVs within glaciology, snow, permafrost, and polar research to support the continued development of high-resolution investigations of cryosphere. We also analyze the UAV and sensor hardware, and data acquisition and processing software in terms of popularity for cryospheric applications and revisit the existing UAV flying regulations in cold regions of the world. The recent usage of UAVs outlined in 103 case studies provide expertise that future investigators should base decisions on.
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Tufail, Ali, Abdallah Namoun, Adnan Ahmed Abi Sen, Ki-Hyung Kim, Ahmed Alrehaili, and Arshad Ali. "Moisture Computing-Based Internet of Vehicles (IoV) Architecture for Smart Cities." Sensors 21, no. 11 (May 30, 2021): 3785. http://dx.doi.org/10.3390/s21113785.
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Recently, the concept of combining ‘things’ on the Internet to provide various services has gained tremendous momentum. Such a concept has also impacted the automotive industry, giving rise to the Internet of Vehicles (IoV). IoV enables Internet connectivity and communication between smart vehicles and other devices on the network. Shifting the computing towards the edge of the network reduces communication delays and provides various services instantly. However, both distributed (i.e., edge computing) and central computing (i.e., cloud computing) architectures suffer from several inherent issues, such as high latency, high infrastructure cost, and performance degradation. We propose a novel concept of computation, which we call moisture computing (MC) to be deployed slightly away from the edge of the network but below the cloud infrastructure. The MC-based IoV architecture can be used to assist smart vehicles in collaborating to solve traffic monitoring, road safety, and management issues. Moreover, the MC can be used to dispatch emergency and roadside assistance in case of incidents and accidents. In contrast to the cloud which covers a broader area, the MC provides smart vehicles with critical information with fewer delays. We argue that the MC can help reduce infrastructure costs efficiently since it requires a medium-scale data center with moderate resources to cover a wider area compared to small-scale data centers in edge computing and large-scale data centers in cloud computing. We performed mathematical analyses to demonstrate that the MC reduces network delays and enhances the response time in contrast to the edge and cloud infrastructure. Moreover, we present a simulation-based implementation to evaluate the computational performance of the MC. Our simulation results show that the total processing time (computation delay and communication delay) is optimized, and delays are minimized in the MC as apposed to the traditional approaches.
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Jian, Liang, Li Xiwen, Zhang Zuti, Luo Xiaohui, and Zhu Yuquan. "Numerical investigation into effects on momentum thrust by nozzle's geometric parameters in water jet propulsion system of autonomous underwater vehicles." Ocean Engineering 123 (September 2016): 327–45. http://dx.doi.org/10.1016/j.oceaneng.2016.07.041.
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Asif, Usman, and Klaus Schmidt. "Fuel Cell Electric Vehicles (FCEV): Policy Advances to Enhance Commercial Success." Sustainability 13, no. 9 (May 4, 2021): 5149. http://dx.doi.org/10.3390/su13095149.
Full textAbstract:
Many initiatives and policies attempt to make our air cleaner by reducing the carbon foot imprint on our planet. Most of the existing and planned initiatives have as their objectives the reduction of carbon dependency and the enhancement of newer or better technologies in the near future. However, numerous policies exist for electric vehicles (EVs), and only some policies address specific issues related to fuel cell electric vehicles (FCEV). The lack of a distinction between the policies for EVs and FCEVs provides obstacles for the advancement of FCEV-related technologies that may otherwise be successful and competitive in the attempt to create a cleaner planet. Unfortunately, the lack of this distinction is not always based on intellectual or scientific evidence. Therefore, governments may need to introduce clearer policy distinctions in order to directly address FCEV-related challenges that may not pertain to other EVs. Unfortunately, lobbyism continues to exist that supports the maintenance of the status quo as new technologies may threaten traditional, less sustainable approaches to provide opportunities for a better environment. This lobbyism has partially succeeded in hindering the advancement of new technologies, partially because the development of new technologies may reduce profit and business opportunities for traditionalists. However, these challenges are slowly overcome as the demand for cleaner air and lower carbon emissions has increased, and a stronger movement toward newer and cleaner technologies has gained momentum. This paper will look at policies that have been either implemented or are in the process of being implemented to address the challenge of overcoming traditional obstacles with respect to the automobile industry. The paper reviewed, synthesized, and discussed policies in the USA, Japan, and the European Union that helped implement new technologies with a focus on FCEVs for larger mass markets. These regions were the focus of this paper because of their particular challenges. South Korea and China were not included in this discussion as these countries already have equal or even more advanced policies and initiatives in place.