Design and Characterization for Regenerative Shock Absorbers

L'abstract è presente nell'allegato / the abstract is in the attachmen

Design and performance of electric shock absorber

The electric shock absorber is a device that converts the kinetic energy of an oscillating object into electric energy. This kinetic energy is normally dumped in a form of thermal energy in a conventional, mechanical shock absorber. The electric shock absorber consists of a permanent magnet linear synchronous generator (PMLSG), a spring, and an electric energy accumulator. The major goal of the project is to design and analyze the operation of an electric shock absorber. In order to define the initial requirements that the electric shock absorber has to satisfy, the construction and performance of currently used shock absorbers were studied first. With respect to this study, five versions of PMLSG were analyzed qualitatively and the most suitable design was selected. The next subject was the design calculations for the chosen type of PMLSG. To determine the dimensions as well as the parameters of its magnetic and electric circuits, the calculation program was written using MATLAB. The designed PMLSG was studied under steady-state conditions to determine its electromechanical characteristics. For this purpose the mathematical model of the generator was proposed and a program was written in MATLAB that allowed calculating its output parameters under different operation conditions. The PMLSG operates practically in dynamic conditions within the whole system: generator – spring – controlled rectified – battery. The dynamic model of the entire system of the electric shock absorber was proposed and described using the voltage equilibrium equation for the electrical port and the force equilibrium equation for the mechanical port. On the basis of these equations, a block diagram was built and simulations were carried out by using MATLAB-SIMULINK. The performance of the electric shock absorber obtained from simulations was compared with mechanical parameters of the mechanical shock absorber. The conclusion obtained indicates that the electric shock absorber is able to store part of the recovered energy in the battery. However, a great part of this energy is lost in the generator resistance and in the external resistance, which is necessary to be connected to the generator output terminal in order to obtain the desire electromechanical parameters

Conceptual design of an advanced Stirling conversion system for terrestrial power generation

A free piston Stirling engine coupled to an electric generator or alternator with a nominal kWe power output absorbing thermal energy from a nominal 100 square meter parabolic solar collector and supplying electric power to a utility grid was identified. The results of the conceptual design study of an Advanced Stirling Conversion System (ASCS) were documented. The objectives are as follows: define the ASCS configuration; provide a manufacturability and cost evaluation; predict ASCS performance over the range of solar input required to produce power; estimate system and major component weights; define engine and electrical power condidtioning control requirements; and define key technology needs not ready by the late 1980s in meeting efficiency, life, cost, and with goalds for the ASCS

Design, implementation, and performance of a distributed and scalable sensor system for critical distance measurements in the CMS detector at LHC

The “CMS Safety Closing Sensors System” (SCSS, or CSS for brevity) is a remote monitoring system design to control safety clearance and tight mechanical movements of parts of the CMS detector, especially during CMS assembly phases. We present the different systems that makes SCSS: its sensor technologies, the readout system, the data acquisition and control software. We also report on calibration and installation details, which determine the resolution and limits of the system. We present as well our experience from the operation of the system and the analysis of the data collected since 2008. Special emphasis is given to study positioning reproducibility during detector assembly and understanding how the magnetic fields influence the detector structure

High Efficiency Ultrathin CIGS Solar Cells

The global demand for renewable energy is growing rapidly. Increasing the global share of alternative sources of energy would not only bring environmental benefits, but also enhance overall energy security by diversifying energy supply. Many technology options exist nowadays to harvest the power of the sun, a sustainable energy source, and generate electricity directly from this source via the photovoltaic effect. Among them, Cu(In,Ga)Se2 (CIGS) has gained significant momentum as a possible high efficiency and low cost thin film solar cell material. The capacity to scale up any photovoltaic technology is one of the criteria that will determine its long term viability. In the case of CIGS, many manufacturers are showing the way for GW-scale production capacity. However, as CIGS technology continues to increase its share of the market, the scarcity and high price of indium will potentially affect its ability to compete with other technologies. One way to avoid this bottleneck is to reduce the importance of indium in the fabrication of the cell simply by reducing its thickness without significant efficiency loss. Reducing the thickness of CIGS thin film will not only save the material but will also lower the production time and the power needed to produce the cell. The material properties of Cu(In,Ga)Se2 thin films are different with deposition process. Many different methods to deposit Cu(In,Ga)Se2 thin film have been tried until now but Cu(In,Ga)Se2 thin films prepared by co-evaporation of elemental sources are the most successful due to the control over the sequence of evaporation of individual material. However, the co-evaporation process is a complex process and, depending on the individual sources and substrate temperature, the thin films are grown with different characteristics. The characteristics of these thin films changes with the change in the atomic percentage (at.%) of Cu, In, Ga and Se, which depends on the evaporation conditions. Among different co-evaporation techniques to grow Cu(In,Ga)Se2, 1-stage, 2-stage and 3-stage co-evaporation processes are the most successful processes. Co-evaporation process is the best technique for highly efficient CIGS solar cell but this process needs a precise control of the elemental composition in the vapor flux in order to achieve high quality material, which is not easy to obtain due to the low sticking coefficient of Selenium. One of the major concerns in Cu(In,Ga)Se2 thin film solar cell fabrication that affect significantly the cell performance during deposition is stoichiometry. CIGS with low Se samples exhibited very low Cu content, additional chalcopyrite phases, very small grain size, and poor solar cell performance. So it is very important to find the minimal selenium flux to obtain high quality Cu(In,Ga)Se2 thin film. During the deposition of ultrathin Cu(In,Ga)Se2 film with 1-stage, 2-stage and 3-stage co-evaporation processes, real time spectroscopic ellipsometry (RTSE) is implemented to study the material properties as well as to monitor the process. The deposition processed for individual layer of CIGS device are optimized to enhance the efficiency of the CIGS solar cell

DESIGN AND OPTIMIZATION OF A FSAE VEHICLE

The purpose of the Formula SAE Competition is to provide students the opportunity to design and build a prototype racecar for an amateur autocross racer and then demonstrate its performance in a competition setting. The project team built upon a car that was originally intended for use in the 2013 FSAE Collegiate Competition. The team performed component evaluation and reviewed past project team’s reports to determine what systems needed to be completed to make the car both operational and competitive. The areas that were addressed included the rear suspension, exhaust, continuously variable transmission (CVT), the body, and the wiring harness. All of the systems addressed were designed and validated. These subsystems were manufactured and integrated with the existing car

Design of a rescue robot for search and mapping operation

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2006Includes bibliographical references (leaves: 65-66)Text in English; Abstract: Turkish and Englishx, 76 leavesThe aim of this thesis is to design a mobile robot for rescue operations after an earthquake. The robot is designed to locate injured victims and life triangle in debris, to create a map of the disaster area and to collect the necessary information needed by digging and support robots in order to the database center. This robot enables us to rescue the victim in the shortest time with minimum injury. This will let us risking the lives of the rescue teams much less as well as rescuing much more victim alive.Robot is designed with the longitudinal body design. Shock absorber system gives the damper effect against falls as well as adding advanced equilibrium properties while passing through a rough land. Driving mechanism is a tracked steering system.Front and back arm system is developed to provide high mobility while overtaking the obstacles.Secondly hovercraft type robot, which works with the cushion pressure principle, is designed as a rescue robot. It is thought that if the adequate height is supplied, the robot could manage to overcome obstacles.As a third design, ball robot, which could easily move uphill and has a capability to overrun obstacles, is studied.Jumping mechanism will be working by magnetic piston.In addition robot is equipped with the sensors so that it has capable of the navigation. In order to achieve feasible sensor systems, all electronic components are evaluated and the most effective sensors are chosen

Linear generators for direct drive marine renewable energy converters

This thesis is concerned with the development of linear generators for use as the power take off mechanism in marine renewable energy converters. Delivering significant power at the low velocities demanded by wave and tidal stream energy converters requires a large force, which must be reacted by an electrical machine in a direct drive system. Attention is focused on the development of two novel topology linear permanent magnet machines suitable for use in this application. For each topology, models are presented that are capable of predicting the force characteristics and dynamic generator performance. The models, which are verified experimentally, reveal significant behavioural differences between the two topologies. The designer is thus provided with an interesting choice when considering a direct drive power take off strategy. In short, a variable reluctance machine is shown to develop a high shear force in its airgap, offering the potential of a compact generator, yet its performance is hindered by a poor power factor and the presence of significant airgap closure forces. The second machine, an air cored stator encompassing a permanent magnet translator, is shown to lend itself favourably as a generator, but only at the expense of requiring a large quantity of magnetic material and developing a significantly lower shear stress. Mechanical issues involved in the direct integration of linear electrical machines into the marine environment are examined. Details of two existing marine renewable energy devices are used to hypothesise about the characteristics of realistic sized generators of both the topologies investigated. Direct drive power take off is shown to represent a feasible alternative to the complex systems frequently proposed in these applications

Thermal integration of electrical power and life support systems for manned space stations

Thermal integration of life support and electrical power systems of six-man space station to obtain maximum utilization of waste energy from power generating syste