Active Control of Shocks and Sonic Boom Ground Signal

The manipulation of a flow field to obtain a desired change is a much heightened subject. Active flow control has been the subject of the major research areas in fluid mechanics for the past two decades. It offers new solutions for mitigation of shock strength, sonic boom alleviation, drag minimization, reducing blade-vortex interaction noise in helicopters, stall control and the performance maximization of existing designs to meet the increasing requirements of the aircraft industries. Despite the wide variety of the potential applications of active flow control, the majority of studies have been performed at subsonic speeds. The active flow control cases were investigated in transonic speed in this study. Although the active flow control provides significant improvements, the sensibility of aerodynamic performance to design parameters makes it a nontrivial and expensive problem, so the designer has to optimize a number of different parameters. For the purpose of gaining understanding of the active flow control concepts, an automated optimization cycle process was generated. Also, the optimization cycle reduces cost and turnaround time. The mass flow coefficient, location, width and angle were chosen as design parameters to maximize the aerodynamic performance of an aircraft. As the main contribution of this study, a detailed parametric study and optimization process were presented. The second step is to appraise the practicability of weakening the shock wave and thereby reducing the wave drag in transonic flight regime using flow control devices such as two dimensional contour bump, individual jet actuator, and also the hybrid control which includes both control devices together, thereby gaining the desired improvements in aerodynamic performance of the air-vehicle. After this study, to improve the aerodynamic performance, the flow control and shape parameters are optimized separately, combined, and in a serial combination. The remarkable part of all these studies is both gradient and non-gradient optimization techniques were used to find the global optimum point. The second part of this study includes investigation of the possibility of weakening the shock strength and the reduction of far field signature by using off-body energy addition. The main obstacle for flying supersonically over land is the detrimental effects of sonic boom on general public and structures. The shock waves generated from various parts of an aircraft flying at supersonic speed, coalesce to form a classic sonic boom acoustic signature, \u27N\u27 wave associated with the sonic boom on the ground. High pressure was imposed on certain parts of the computational domain to simulate the pulsed laser effects, and then the propagation and interaction of this pulsed shock with shock waves generated from the diamond shaped model were investigated. Optimization of the location and the power of the pulsed shock were achieved using the non-gradient optimization technique. The main contribution of this study is the optimization of the parameters of pulsed shock

Clean Alternatives For Household Coal - Case Study: Izmir, Turkey

Household coal consumption during the heating season affects Izmir’s air quality adversely to the point where air quality indicators show that pollution levels exceed limit concentration values that World Health Organization set for a habitable and healthy ambient air. The objective of this paper is to evaluate alternatives that utilize low-carbon emitting methods of domestic heating fueled by renewable energy sources and develop a model which would replace household coal. Research shows that 223,969 tonnes of coal were burned in households of Izmir in 2019 and analysis results show that 2.72 million MMBtu of heat energy was supplied to these households from burning coal. Considering the high potential for wind and solar energy in Izmir, the proposed model utilizes a combination of heating with natural gas, electric heaters, air-source heat pumps and ground source heat pumps that would be powered by solar PVs and wind turbines. Cost analysis reveals that an initial investment of 1,346,706,220 Turkish Liras is required where the elimination of household coal would prevent approximately 58 premature deaths and 189 disease cases related to ambient and household air pollution per year. The legislature and policy ideas for supporting this transformation are investigated and other possible ways of generating clean electricity and more efficient household heating methods are discussed

The sustainability of blockchain

openBlockchain technology is considered one of the most fascinating technology in the last 20 years. Blockchain system needs improvements due to their problems as all technologies are needed in their lifetime. The major problems are the energy consumption level and CO2 emissions are released into the environment through mining activities. In this thesis, it will be discussed these issues and possible solutions about how to improve blockchain technology as being environmentally friendly

The limits to moral erosion in markets: social norms and the replacement excuse

This paper studies the impact of a key feature of competitive markets on moral behavior: the possibility that a competitor will step in and conclude the deal if a conscientious market actor forgoes a profitable business opportunity for ethical reasons. We study experimentally whether people employ the argument "if I don’t do it, someone else will" to justify taking a narrowly self-interested action. Our data reveal a clear pattern. Subjects do not employ the "replacement excuse" if a social norm exists that classifies the selfish action as immoral. But if no social norm exists, subjects are more inclined to take a selfish action in situations where another subject can otherwise take it. By demonstrating the importance of social norms of moral behavior for limiting the power of the replacement excuse, our paper informs the long-standing debate on the effect of markets on morals

The limits to moral erosion in markets: Social norms and the replacement excuse

This paper studies the impact of a key feature of competitive markets on moral behavior: the possibility that a competitor might step in and conclude the deal if a conscientious market actor forgoes a profitable business opportunity for ethical reasons. In a series of experiments, we study whether people invoke the replacement excuse, that is, the argument “if I don't do it, someone else will,” to justify narrowly self-interested actions. Our data are consistent with the possibility that the existence of a clear social norm of moral conduct can limit the impact of the availability of the replacement excuse on behavior

INCLUSIVE STATIONS: Gates into the city of Rotterdam

In the Dutch National Environmental Vision 2021, new living and working locations are mapped on existing urbanized sites - mainly at catchment areas of public transportation (PT) nodes or stations [1]. This is the case in the metropolitan area of Rotterdam, where new developments projects are taking place at several station locations. In the Rotterdam Mobility Plan [2] “inclusiveness in mobility†is emphasized by setting several objectives for a PT node. These objectives address the mixité of facilities and attractiveness at station locations with public spaces, accessibility with more bikes (and sustainable modes of transport) and fewer cars in the city centre [3]. How could the station as a node respond to future challenges of seamless travel, inclusivity and the changing intensity of cars and pedestrian flows both in the centre and the periphery of the city of Rotterdam? The following pages intend to answer this question through the narrative of six research-by-design projects, conducted by the students of Complex Projects group and enrolled in “City of Innovations Project†elective, “Inclusive Stations’’. Working in close collaboration with the City of Rotterdam, teachers and design professionals, the students were asked to reflect on the importance of transport networks within and extending from the city. Through considering the way these networks have shaped the city by weaving the urbanites of the city center(s) and suburban areas, this elective has been focused on three station locations which act as gateways to the city center of Rotterdam: Meijersplein Airport station, Rotterdam Alexander rail-metro station and Slinge metro station. The ‘6 Visions X 3 Locations’ chapter is a systematization of the work of 27 masters students with input from designers of the City of Rotterdam, Delta Metropool Association and De Zwarte Hond. The research-through-design process consists of documenting and analysing the present urban conditions of selected station locations and proposing design solutions and visualisations of the development of these locations. It shows the methodology of the process that sees the interaction between students-teachers-professionals on a weekly basis through thematic workshops, lectures and site visits in Rotterdam. The elective “City of Innovations Project - Inclusive Stations’’ is connected to current research and design studios of Complex Projects group at the Department of Architecture dealing with the role of infrastructure as a catalyst of urban developments. This output is a follow up of recent publications by Complex Projects, such as: “Living Stations†(2020), “Amsterdam 2050†(2019) and “Stations as Nodes†(2018) published by TU Delft open. [1] More info: https://www.novistukken.nl/english/default.aspx [2] More info: http://tda-mobility.org/wp-content/uploads/2018/11/Rotterdam_Urban-Traffic_Plan.pdf [3] Triggianese, M. (2021). Stations as a lever for inclusive growth. In M. Triggianese, O. Caso, & Y. Söylev (Eds.), Living Stations: The Design of Metro Stations in the (east flank) metropolitan areas of Rotterdam (pp.8-13). TU Delft Open

Vibration control of vehicles with active tuned mass damper

The purpose of this paper is to propose an alternative approach on controlling of vehicle vibrations by using active tuned mass damper. The approach is presented by simulation of a quarter-car model. Initially, a tuned mass damper is integrated on a vehicle model and its optimal parameters are determined by using 3D diagram of the maximum magnitudes of the sprung mass frequency response functions. Active control is obtained by adding an actuator element parallel to tuned mass damper. The fuzzy-sliding mode control method is utilized in reducing the displacement and acceleration magnitudes of sprung mass. Finally, comparison of active and passive responses in frequency and time domain are given to demonstrate vibration control improvement