<p>Accelerated life testing (ALT) is commonly used to obtain the reliability (lifetime) of a system in a short period by applying severe stress factors (i.e. temperature, humidity, chemical etc.,) to the system. Accelerated life testing was done on 2N3904 N-P-N bipolar junction transistor. After accelerated life testing, the acceleration factor is calculated through statistical analysis to predict the lifetime of a system at a certain operating condition. Multiple temperature and water immersed experiments were conducted on transistors at various temperatures. With the obtained results, analysis was done on the data to predict lifetime of transistors at different environmental conditions. Effects of the environmental conditions on the transistors were also discussed. Corrosion effects on transistors were studied. ALTA software is used to analyze the experimental data and to calculate the lifetime of the transistors. From the obtained failure data prediction of mean time to failure at various temperatures was done. </p>

The fact that many banks today target students with concessional deals is no news. Students are a coveted group at the financial institutions, above all because they will most likely have a secure and well paid occupancy after they have finished their studies. This study will show the importance of banks attracting the students as customers and that the students will continue being customers even after having finalised their studies. It will also show that the banks market themselves towards the students as if students were a homogenous group as well as proving the benefits of calculating a student’s Customer Lifetime Value (CLV). The study is based on research articles within the subject, one interview with the CEO at one of the banks in Sweden and two surveys that were sent out to 10 000 people that are either part of a current student deal at a bank or has been. The result shows that the bank will increase its long-­‐term profitability if it has more students in the customer base. Given that the students remain as customers of the bank after their studies are finished. The results also show the significance of dividing the group "students" based on chosen variables depending on the banks objective and CLV. From this it is concluded that it is less expensive reaching out to the academic meritorious customers in an early stage then to obtain these customers hindsight. / Att många banker riktar sig mot studenter med förmånliga erbjudanden är ingen nyhet. Studenter  är  en  eftertraktad  målgrupp  hos  de  finansiella  institutionerna,  framför  allt eftersom chansen är stor att studenter efter studierna kommer att få välbetalda jobb. Den  här  studien  kommer  att  visa  vikten  av  att  banker  attraherar  studenter  som bankkunder och att studenter fortsätter att vara bankkunder efter avslutade studier. Den kommer även visa att banker marknadsför sig mot alla studenter som en homogen målgrupp, samt fördelarna med att räkna ut en students Customer Lifetime Value (CLV). Underlaget till studien är forskningsartiklar och rapporter inom ämnet, en intervju med en VD för en svensk bank och två enkäter som skickats ut till 10 000 personer som antingen är med i ett studenterbjudande hos en bank eller har varit det. Resultaten visar att  banker  skulle  öka  sin  långsiktiga  lönsamhet  om  de  hade  fler  studenter  som bankkunder, förutsatt att de stannar kvar som kunder efter avslutade studier. Resultatet visar även  betydelsen av  att  dela upp  studenterna i  mindre delsegment efter valda variabler beroende på bankens målsättning och CLV. Utifrån detta dras slutsatsen att det är mindre kostsamt att nå ut till de akademiskt meriterade kunderna i ett tidigt skede än att erhålla dessa kunder i efterhand.

This dissertation explores articulations of Black Womanhood during the socio-political crisis of police brutality against Black women during the 2010s. I use Stuart Hall’s concepts of conjuncture and articulation as the orientation to analyze three of Lifetime’s original reality television programs: Dance Moms, Bring It!, and Girlfriend Intervention. I contend that the discourses on these shows create articulations of Black womanhood that fail to reflect the realities of the complex social struggles and state-sanctioned police violence against unarmed Black women that led to the #SayHerName movement. Rather than portray the full realities of the Black female experience, the shows conceal the social unsettling experiences of being a Black woman in order to bring entertaining and banal discourses to the forefront. As such, those reductive articulations of Black Womanhood act as an unstable settlement, a temporary joist to the national social formation in an attempt to avoid radical socio-political reconfigurations.

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Photoluminescence spectroscopy is one of the most efficient and sensitive non-contact techniques used to investigate defects in SiC. In this work, room temperature photoluminescence mapping is employed to identify different defects that influence material properties. The correlation of the distribution of these defects in n-type 4H-SiC substrates with electronic properties of SiC revealed connection between the deep levels acting as efficient recombination centers and doping in the substrate. Since deep levels are known to act as minority carrier lifetime killers, the obtained knowledge may contribute to our ability to control important characteristics such as minority carrier lifetime in SiC. In semi-insulating (SI) 6H-SiC, the correlation between room temperature infrared photoluminescence maps and the resistivity maps is used to identify deep defects responsible for semi-insulating behavior of the material. Different defects were found to be important in different families of SI SiC substrates, with often more than one type of defect playing a significant role. The obtained knowledge is expected to enhance the yield of SI SiC fabrication and the homogeneity of the resistivity distribution across the area of large SiC substrates.

A novel experimental technique has been developed for measuring the light trapping enhancement and the carrier recombination lifetime in silicon wafers. The technique is based on the pump/probe modulated free carrier absorption (MFCA) method, where the probe beam, attenuated by generated free carriers, carries information about the effective lifetime and the average light path enhancement in a textured silicon wafer. For the first time, a reflection mode MFCA technique is presented where the reflected part of the probe beam is used to perform measurements, while the conventional technique is based on measurements of the transmitted part of the probe beam. A theoretical model is presented to explain the behavior of the light beam in double-side polished and double-side textured silicon wafers. The model yields good agreement with the experimental results and explains the difference in the amplitudes of the reflected and transmitted signals. The results of the experimental measurements of the light path enhancement in a double-side textured sample are analyzed and the reasons for their deviation from the Lambertian limit are discussed. This work presents new applications of the MFCA technique and shows how it can be used for the simultaneous determination of more than one crucial characteristic of silicon solar cells. / Thesis / Master of Applied Science (MASc)

Reliability experiments provide important information regarding the life of a product, including how various factors may affect product life. Current analyses of reliability data usually assume a completely randomized design. However, reliability experiments frequently contain subsampling which is a restriction on randomization. A typical experiment involves applying treatments to test stands, with several items placed on each test stand. In addition, raw materials used in experiments are often produced in batches. In some cases one batch may not be large enough to provide materials for the entire experiment and more than one batch must be used. These batches lead to a design involving blocks. This dissertation proposes two methods for analyzing reliability experiments with random blocks and subsampling. The first method is a two-stage method which can be implemented in software used by most practitioners, but has some limitations. Therefore, a more rigorous nonlinear mixed model method is proposed. / Ph. D.

Fluorescence lifetime imaging (FLIM) has the potential to provide rapid screening and detection of diseases. However, time-resolved fluorescence measurements require high-performance detectors with single-photon sensitivity and sub-nanosecond time resolution. These systems should also be compact, reliable, inexpensive, and easily deployable for laboratory and clinical applications. It is with these applications in mind that the development of single photon avalanche diodes (SPAD) and time-to-digital converter (TDC) prototype integrated circuits (IC) in standard digital CMOS have been pursued in this thesis. SPAD and TDC ICs were designed and fabricated in 130 nm IBM CMOS technology and then intensively studied. Several different SPAD pixels were modeled and designed, and the electro-optical performance was characterized and comparatively studied. By repurposing existing design layers of a standard CMOS process, the fabricated SPAD pixel test structures achieved up to 20× improvement of dark count rate (DCR) compared to previous designs. Optical measurements also showed up to 10× improvement in the detection limits for low-level light. Detailed dark noise characterization was performed at various temperatures using free-running and time-gated modes of operation. Optimal operating conditions were found for minimal afterpulsing effects. The SPAD’s capability to accurately measure fast fluorescence decays was also demonstrated in a practical setting with the lifetime measurements of two fluorophores, Rhodamine 6G and Ruby crystal, which have fluorescence lifetimes of approximately 4 ns and 3 ms, respectively. A fast and accurate TDC prototype circuit for time-correlated single-photon counting (TCSPC) applications was designed, fabricated and characterized. With a coarse-fine delay line architecture, the TDC size was reduced without compromising its linearity and jitter performance. Extensive characterization of the fabricated SPAD and TDC ICs shows that the measured performance met the stated design goals. / Thesis / Doctor of Philosophy (PhD)

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