Uncooled Infrared Detector Featuring Silicon based Nanoscale Thermocouple

The main focus of this dissertation is to improve the performance of thermoelectric (TE) infrared (IR) detectors. TE IR detectors are part of uncooled detectors that can operate at room temperature. These detectors have been around for many years, however, their performance has been lower than their contesting technologies. A novel high-responsivity uncooled thermoelectric infrared detector is designed, fabricated, and characterized. This detector features a single standalone polysilicon-based thermocouple (without a supporting membrane) covered by an umbrellalike optical-cavity IR absorber. It is proved that the highest responsivity in the developed detectors can be achieved with only one thermocouple. Since the sub-micrometer polysilicon TE wires are the only heat path from the hot junction to the substrate, a superior thermal isolation is achieved. A responsivity of 1800 V/W and a detectivity of 2 ? 10^8 (cm. sqrt(Hz)W^?1) are measured from a 20?m x 20?m detector comparable to the performance of detectors used in commercial focal planar arrays. This performance in a compact and manufacturable design elevates the position of thermoelectric IR sensors as a candidate for low-power, high performance, and inexpensive focal planar arrays. The improvement in performance is mostly due to low thermal conductivity of thin polysilicon wires. A feature is designed and fabricated to characterize the thermal conductivity of such a wire and it is shown for the first time that the thermal conductivity of thin polysilicon films can be much lower than that of the bulk. Thermal conductivity of ~110nm LPCVD polysilicon deposited at 620C is measured to be ~3.5W/m.K

A Reading of Flannery O’Connors “Everything that Rises Must Converge”

Everything that rises must converge is a short story which, without the aid of suspense that is often provoked in fiction by actions hanging on a bare thread in a whirling plot of intertwining – and perhaps incredible – events, catches the reader‟s attention until the very last word. The plot of the story could not be any simpler; a young bachelor takes his overweight mother by bus to a „reducing class‟ but before they reach the place the mother changes her mind, heads back home, has a stroke and is left by her helpless son dying or maybe dead as he goes to seek help. But parallel to the plot of events is a “plot" of revelation; as the insignificantly banal happenings take place, an unfolding of character slowly emerges before the reader‟s eyes

Deconstructing Assumptions in A Jury of Her Peers

A Jury of Her Peers is truly a small masterpiece. Set in limited rural community, it reaches far back to eons of lost history. From the vivid dramatic scenes and from the heart of a feminine reticence embedded in them, it seems that a desperate cry against injustice toward women echoes. The Minnie Foster who we never meet has an imposing spiritual presence from start to end. Her pitiful silence seems to lament the dark shadow of cruelty and suffering which has overwhelmed of the life of despondent women throughout history. Following her final, desperate attempt to defend herself from being wholly crushed she is subdued by a burden heavier than that from which she had tried to escape. From the rough unsympathetic hands of a husband she is put under the glaring stare of cold uncaring law. What becomes of her remains unknown, just as the lament of her pitiful cry for justice remains unfulfilled

A Reading of Joseph Conrad's The Tale

The Tale is a short story by Joseph Conrad. Typical of a Conrad story it is set at sea. The sea is symbolic of the unconscious and this story may be read as a story of the unconscious. On the outside, it seems simple; a man tells a woman a tale of the commanding officer of a patrol ship who gives false directions to another ship and sends it to its doom. In between the lines of the seemingly simple plot, however, can be read another tale; one which speaks of a human sea deeper than the sea of water; deeper, darker, and infinitely more mysterious. Man has navigated the sea of water but the unfathomed sea of his own being remains, for the most part, undiscovered. This is a sea different from the sea of this world and Conrad sets sail on it by telling a tale from another world. Sailing with Conrad, the reader can look out on the infinite vastness and try to form a picture of the infinite depth of a sea which is not visible to the human eye

Images of the Female Countenance in Renaissance Literature

In her article "The politics of gender" Elaine Hobby gives a clear image of the confusion evoked in modern mentality by the juxtaposition of Renaissance literature and history. The romantic scenes portrayed in the wonderland of Renaissance poetry seem uncompromisable with the bare facts of historical record. As we contemplate the shadows obscuring the male permeated poetic language of the age however, we do discern spots of light illuminating the overall picture. The age has its own logic and its own language and although neither may be wholly appealing to the modern palate, both are, within their own historical framework, unequivocal and self-consciously assertive

PL-MODT and PL-MODMC : two codes for reliability and availability analysis of complex technical systems using the fault tree modularization technique

"November 1978."Includes bibliographical referencesThe methodology used in the PL-MOD code has been extended to include the time-dependent behavior of the fault tree components. Four classes of components are defined to model time-dependent fault tree leaves. Mathematical simplifications are applied to predict the time-dependent behavior of simple modules in the fault tree from its input components' failure data. The extended code, PL-MODT, handles time-dependent problems based on the mathematical models that have been established. An automatic tree reduction feature is also incorporated into this code. This reduction is based on the Vesely-Fussell importance measure that the code calculates. A CUT-OFF value is defined and incorporated into the code. Any module or component in the fault tree whose V-F importance is less than this value will automatically be eliminated from the tree. In order to benchmark the PL-MODT code, a number of systems are analyzed. The results are in good agreement with other codes, such as FRANTIC and KITT. The computation times are comparable and in most of the cases are even lower for the PL-MODT code compared to the others. In addition, a Monte-Carlo simulation code (PL-MODMC) is developed to propagate uncertainties in the failure rates of the components to the top event of a fault tree. An efficient sorting routine similar to the one used in the LIMITS code is employed in the PL-MODMC code. Upon modularization the code proceeds and propagates uncertainties in the failure rates through the tree. Large fault trees such as the LPRS fault tree as well as some smaller ones have been analyzed for simulation, and the results for the LPRS are in fair agreement with the WASH-1400 predictions for the number of simulations performed. The codes PL-MODT and PL-MODMC are written in PL/l language which offers the extensive use of the list processing tools. First experience indicates that these codes are very efficient and accurate, specifically for the analysis of very large and complex fault treesSponsored by the NR

Reliability analysis of complex technical systems using the fault tree modularization technique

Originally presented as the first author's thesis, (Ph. D.)--in the M.I.T. Dept. of Nuclear Engineering, 1980Includes bibliographical reference