Thermosonic ball bonding is the most popular method used to create electrical interconnects between integrated circuits (ICs) and substrates in the microelectronics industry. Traditionally gold (Au) wire is used, however with industry demands for lower costs and higher performance, novel wire materials are being considered. Some of these wire materials include Cu, insulated, and coated wires. The most promising of which being Cu wire. Some of the main issues with these wire materials is their performance in the electrical flame off (EFO) step of the wire bonding process. In the EFO step a ball called the free air ball (FAB) is formed on the end of the wire. The quality of the FAB is essential for reliable and strong ball bonds. In Cu wire bonding the hardness of the FAB and oxidation are the main issues. A hard FAB requires larger bonding forces and US levels to make the bond which increases the likelihood of damage to the IC. Excessive oxidation acts as a contaminant at the bond interface and can also influence the shape of the FAB. Shielding gases are required to reduce oxidation and improve FAB quality. This thesis focuses on the EFO process and the influence of EFO parameters and shielding gases on Au and Cu FABs. The primary focus of this thesis is to provide a better understanding of the EFO process in order to expedite the introduction of novel wire materials into industry. Several different experiments are performed on an automated thermosonic wire bonder with 25 µm Au and Cu wires to investigate the EFO process during ball bonding. The effects of EFO parameters on the hardness and work hardening of FABs and the effects of shielding gas type and flow rates on the quality of the FABs are determined. The EFO discharge characteristics in different shielding gases is also studied to better understand how the composition of the atmosphere the FAB is formed in influences the energy input via the EFO electrical discharge. Using the online deformability method and Vickers microhardness testing it is found that the EFO current (IEFO) and EFO time (tEFO) have a large influence on the hardness and work hardening of Au and Cu FABs. A harder FAB produced with a large IEFO and low tEFO will work harden less during deformation. The bonded ball will be softer than that of a FAB produced with a lower IEFO and higher tEFO. The online deformability method is found to be twice as precise as the Vickers microhardness test. An online method for characterizing the quality of FABs is developed and used to identify shielding gas flow rates that produce defective FABs. The EFO process for an Au wire and two Cu wire materials is investigated in flow rates of 0.2-1.0 l/min of forming gas (5 % H2 + 95 % N2) and N2 gas. All three of the most common FAB defects are identified with this online method. It is found that good quality FABs cannot be produced above flow rates of 0.7 l/min and that H2 in the shielding gas adds a thermal component to the EFO process. It is recommended that the gas flow rate be optimized for each new wire type used. The EFO discharge power is measured to be 12 % higher in a N2 gas atmosphere than in a forming gas atmosphere. The lower ionization potential of the forming gas leads to a higher degree of ionization and therefore lower resistance across the discharge gap. It was found that the discharge power does not determine the energy transferred to the wire anode because the Au FAB produced in forming gas has a 6 % larger diameter than that of the FABs produced in N2 gas. Other factors that effect the voltage of the EFO discharge include the controlled EFO current, the discharge gap, and the wire anode material.

The purpose of this master thesis project has been to analyze and document the Sirius 2001 Concept Car. In addition, it has also been a goal to get the car in a usable state by implementing new software on the on board computers. The car is a Tiger Cat E1 that is modified with four wheel steering and an advanced X-by-Wire system. The computers in the X-by-Wire system consist of six TTP PowerNodes that communicate with each other over a redundant, fault tolerant TTP/C communications bus. The computers are connected to a number of sensors and actuators to be able to control the car. This project has contributed to the car in several ways. A complete documentation of the systems implemented in the car is one. Another is a programmers manual which significantly lowers the threshold when working with the car. Last but not least is the modifications in hardware and software, which have made the car usable and show some of the possibilities with the system. The results show that the Sirius 2001 Concept Car is a suitable platform for research in car dynamics and fault tolerant systems. The work has also shown that the TTP/C communication model works well in an application like this.

Thermosonic ball bonding is the most popular method used to create electrical interconnects between integrated circuits (ICs) and substrates in the microelectronics industry. Traditionally gold (Au) wire is used, however with industry demands for lower costs and higher performance, novel wire materials are being considered. Some of these wire materials include Cu, insulated, and coated wires. The most promising of which being Cu wire. Some of the main issues with these wire materials is their performance in the electrical flame off (EFO) step of the wire bonding process. In the EFO step a ball called the free air ball (FAB) is formed on the end of the wire. The quality of the FAB is essential for reliable and strong ball bonds. In Cu wire bonding the hardness of the FAB and oxidation are the main issues. A hard FAB requires larger bonding forces and US levels to make the bond which increases the likelihood of damage to the IC. Excessive oxidation acts as a contaminant at the bond interface and can also influence the shape of the FAB. Shielding gases are required to reduce oxidation and improve FAB quality. This thesis focuses on the EFO process and the influence of EFO parameters and shielding gases on Au and Cu FABs. The primary focus of this thesis is to provide a better understanding of the EFO process in order to expedite the introduction of novel wire materials into industry. Several different experiments are performed on an automated thermosonic wire bonder with 25 µm Au and Cu wires to investigate the EFO process during ball bonding. The effects of EFO parameters on the hardness and work hardening of FABs and the effects of shielding gas type and flow rates on the quality of the FABs are determined. The EFO discharge characteristics in different shielding gases is also studied to better understand how the composition of the atmosphere the FAB is formed in influences the energy input via the EFO electrical discharge. Using the online deformability method and Vickers microhardness testing it is found that the EFO current (IEFO) and EFO time (tEFO) have a large influence on the hardness and work hardening of Au and Cu FABs. A harder FAB produced with a large IEFO and low tEFO will work harden less during deformation. The bonded ball will be softer than that of a FAB produced with a lower IEFO and higher tEFO. The online deformability method is found to be twice as precise as the Vickers microhardness test. An online method for characterizing the quality of FABs is developed and used to identify shielding gas flow rates that produce defective FABs. The EFO process for an Au wire and two Cu wire materials is investigated in flow rates of 0.2-1.0 l/min of forming gas (5 % H2 + 95 % N2) and N2 gas. All three of the most common FAB defects are identified with this online method. It is found that good quality FABs cannot be produced above flow rates of 0.7 l/min and that H2 in the shielding gas adds a thermal component to the EFO process. It is recommended that the gas flow rate be optimized for each new wire type used. The EFO discharge power is measured to be 12 % higher in a N2 gas atmosphere than in a forming gas atmosphere. The lower ionization potential of the forming gas leads to a higher degree of ionization and therefore lower resistance across the discharge gap. It was found that the discharge power does not determine the energy transferred to the wire anode because the Au FAB produced in forming gas has a 6 % larger diameter than that of the FABs produced in N2 gas. Other factors that effect the voltage of the EFO discharge include the controlled EFO current, the discharge gap, and the wire anode material.

Wire Electric Discharge Machining (wire-EDM) is a non-traditional machining process. Controlled electric sparks are successively used to vaporize part of a workpiece along a programmed path in order to machine a desired part. Because there is no tool that comes in direct contact with the workpiece, it is possible to machine thin, delicate parts. This thesis was designed to observe and analyze the differences in cutting capabilities for a conventional wire-EDM machine when cutting thin-walled sections from five commonly used metals utilizing a variation of roughing and finishing passes. The five metals that were used in this study are: Aluminum 6061 T6, Yellow Brass SS360, 420 Stainless Steel, D2 Tool Steel at 25 to 30 RC, and D2 Tool Steel at 60 to 65 RC. The thin-walled sections were constrained on each end by the parent material to which they remained attached, and they ranged in thickness from 0.05 millimeters (0.002 inches) increasing incrementally by 0.05 millimeters (0.002 inches) until they reached a thickness of 0.30 millimeters (0.012 inches). A Sodick AQ325L wire-EDM machine was employed to perform the machining. It was observed that differences exist in the capabilities of cutting thin-walled sections from the five different metals. This could be both observed visually through inspection and statistically through the analysis of each data set obtained by measuring the resultant thickness of each section. It was also observed that differences exist for the same material while utilizing the variations of cutting parameters: a roughing with no finishing passes, a roughing with one finishing pass, and a roughing with three finishing passes. Thus both the material properties and the cutting parameters play a significant role in determining the capability of cutting thin-walled sections with a wire-EDM machine.

During the summer excess energy is produced from solar heaters, this is not taken care of, and usually goes to waste. The base of the project is built on that you should take the excess energy during the warmest months of the summer and save the energy in boreholes in the ground, then during the colder months the energy can be used. The purpose of the project was to build a prototype for the control and monitoring of a system. With this project we want to present a solution to a prototype which can be used as a development platform for the client. Communication between the actuators, sensors and the controller is made via a CAN-bus. The temperature sensors uses a One-wire buss and its values are stored and can be shown on a website. The results show that the monitoring and control functions works. Theoretically, the prototype is designed to be expanded to a real application. / Under sommaren produceras överbliven energi från solvärmare, denna tas inte omhand utan går oftast till spillo. Projektets grund bygger på att ta den överblivna energin under de varmaste månaderna på sommaren och spara undan energin i borrhål i marken, för att sedan under kallare månader kunna använda detta. Syftet med projektet har varit att bygga en prototyp för styrning och övervakning av ett system. Med detta projekt vill vi visa en lösning på en prototyp som kan fungera som utvecklingsplattform för beställaren. Kommunikation mellan aktuatorer, sensorer och styrenhet görs via en CAN-buss. Temperaturensorernas använder sig av en One-wire buss och dess värden sparas och kan avläsas på en webbplats. Resultatet visar att övervakning av sensordata och reglering av aktuatorer fungerar. Teoretiskt sett är prototypen utformad för att expanderas till en verklig applikation.

Master of Science / Department of Civil Engineering / Robert J. Peterman / Prestressed concrete is commonly used for bridges, pavement and railroad ties because of economic advantages in cost, sustainability service life, and environmental friendliness. In general concrete design standard, the ultimate moment strength in flexure design is computed by finding the equilibrium of the internal force in the section (the compressive force in concrete and tension force in the steel and reinforcement). To predict tension force in steel one generally applies the 7-wire low-relaxation prestressing strand equation from the PCI manual even though the design employed prestressing wires instead of strand. The other method is to use equations from the ACI Code which is over conservative. Considering both approaches are lack accuracy, this research will provide an accurate estimation of the stress in prestressing wires through an experimental program and analytical modeling. The real stress-strain curves are collected through experimental testing in 13 types of prestressing wire. Experimental results are then used for modeling existing equations. As a result a more precise estimation is achieved. Additionally, this research simplifies the procedure for utilizing the equations which offers convenience in practical application.

A more accurate and flexible grid analysis is achieved through an adaptive and dynamic calculation of line parameters. This is needed for future smart grid implementation. The primary objective of this thesis is to analyze the calculation of transmission line parameters. The impact certain assumptions have on the accuracy of line parameters and fault location algorithms are evaluated. In particular, the impact of the grounded shield wire assumption on the accuracy of fault location algorithms is analyzed. This implies that the impedance of towers be taken into consideration, rather than the simplification of a direct connection of the earth wire to ground. Secondly, the phenomenon of skin-effect is analyzed and evaluated in regards to a more accurate representation of line parameters and a minimization of parameter inaccuracy. / text

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The introduction of fly-by-wire electronic flight control systems into transport aircraft has given the flying qualities engineer the opportunity to optimise the flying qualities of these aircraft for their specific tasks. With this technology has come the opportunity to introduce new technologies into the cockpit, such as non-linked or backfed sidesticks and non-backfed throttle levers. A comparative survey of airline pilots flying such a very high technology unconventional aircraft and a high technology but conventional aircraft suggests that these technologies may reduce the available channels of communication to the pilot in the very high technology aircraft, resulting in the possibility of reduced situational awareness. A closed loop piloted simulation survey of ten transport aircraft in current operation was undertaken which demonstrated that they all suffered from flying qualities deficiencies, limiting the performance that the pilot could achieve. In particular poor dynamics precluded the pilot adopting tight closed loop, or compensatory, control. Instead it was necessary to adopt a more open loop, precognitive, technique with medium frequency modulation, resulting in a degradation in landing performance. Through appropriate flight control system design it should be possible to produce aircraft that can be flown using the full range of control inputs from open to closed loop. The major study of this thesis assessed, through piloted simulation evaluations, the suitability of a wide range of longitudinal commanded response types for the approach and landing tasks. It was concluded that a response type that closely resembles that of angle of attack is optimum for these tasks due to its conventional characteristics of speed stability on the approach and monotonic stick forces in the flare. Such a system, appropriately implemented, should allow the transport aircraft pilot the full range of piloted control inputs, from open loop, precognitive, to closed loop, compensatory, resulting in improved landing performance.