Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, NICE-OHMS, is a laser-based spectroscopic detection technique that comprises the concepts of frequency modulation (FM, for reduction of 1/f-noise by detecting the signal at a high frequency) and cavity enhancement (CE, for a prolongation of the optical path length) in a unique way. Properly designed, this gives the technique an intrinsic immunity against the frequency-to-noise conversion that limits many other types of CE techniques. All this gives it an exceptionally high sensitivity for detection of molecular species. Although originally developed for frequency standard purposes in the late 1990s, soon thereafter development of the technique towards molecular spectroscopy and trace gas detection was initiated. This thesis focuses on the further development of Doppler- broadened NICE-OHMS towards an ultra-sensitive detection technique. A number of concepts have been addressed. A few of these are: i) The detection sensitivity of fiber-laser-based NICE- OHMS has been improved to the 10−12 cm−1 range, which for detection of C2H2 corresponds to a few ppt (parts-per-trillion, 1:1012) in gas phase, by improving the locking of the laser to a cavity mode by use of an acousto-optic modulator. ii) It is shown that the system can be realized with a more compact footprint by implementation of a fiber-optic circulator. iii) A systematic and thorough investigation of the experimental conditions that provide maximum signals, referred to as the optimum conditions, e.g. modulation and demodulation conditions and cavity length, has been performed. As a part of this, an expression for the NICE-OHMS line shape beyond the conventional triplet formalism has been proposed and verified. iv) To widen the applicability of NICE-OHMS for detection of pressure broadened signals, also a setup based upon a distributed-feedback (DFB) laser has been realized. v) In this regime, the Voigt profile cannot model signals with the accuracy that is needed for a proper assessment of analyte concentrations. Therefore, the thesis demonstrates the first implementations of line profiles encompassing Dicke narrowing and speed-dependent effects to NICE-OHMS. While such profiles are well-known for absorption, there were no expressions available for their dispersion counterparts. Such expressions have been derived and validated by accompanying experiments. vi) The applicability of the technique for elemental detection, then referred to as NICE-AAS, has been prophesied. / Brusimmun kavitetsförstärkt optisk-heterodyndetekterad molekylärspektroskopi (NICE-OHMS) är en laser-baserad spektroskopisk teknik som förenar frekvensmodulation (för reducring av 1/f-brus genom detektion vid en hög frekvens) och kavitetsförstärkning (KF, för en förlängning av den optiska väglangden) på ett unikt sätt. Korrekt realiserad uppvisar tekniken en inneboende immunitet mot omvandling av frekvensbrus till intensitetsbrus som många andra KF-tekniker är begränsade av. Allt detta ger tekniken en exceptionellt hög känslighet för molekyldetektion. Ursprungligen utvecklad för frekvensstandardändamål i slutet av 1990, har den sedan dess utvecklats för molekylspektroskopi och spårgasdetektering. Denna avhandling fokuserar på vidareutvecklingen av NICE-OHMS mot en tillämpbar, ultrakänslig detektionsteknik. Ett antal koncept har adresserats. Några av dessa är: i) Detektionskänsligheten hos fiberlaserbaserad NICE-OHMS har förbättrats till 10-12 cm-1 området, vilket för detektion av C2H2 i gasfas motsvarar några få ppt (parts per biljon, 1:1012), genom att förbättra låsningen av lasern till en kavitetsmod med hjälp av en akustooptisk modulator. ii) Det har demonstrerats att NICE-OHMS kan realiseras mer kompakt med hjälp av en fiber-kopplad optisk cirkulator. iii) En systematisk och grundlig utredning av de experimentella förhållanden som ger maximala signaler, betecknade de optimala förhållanden, t.ex. modulering och demodulering och kavitetslängden, har utförts. Som ett led i detta har ett uttryck för NICE-OHMS linjeform bortom den konventionella triplett formalismen föreslagits och verifierats. iv) För att bredda tillämpbarheten av NICE-OHMS för detektering av tryckbreddade signaler har även en instrumentering baserad på en distribuerad-återkopplad (eng. distributed feedback, DFB) laser realiserats. v) I detta område kan inte Voigt profilen modellera signalen med den noggrannhet som krävs för en korrekt bedömning av analytkoncentrationer. Därför visar avhandlingen de första implementeringarna i NICE-OHMS av linjeprofiler som inkluderar Dicke avsmalning (eng. Dicke narrowing) och hastighetsberoende effekter (eng. speed-dependent effects). Emedan sådana profiler är välkända för absorption, fanns det inga uttryck för deras dispersiva motparter. Sådana uttryck har därför härletts och validerats av medföljande experiment. vi) Tillämpbarheten av tekniken för detektion av atomer, NICE-AAS, har diskuterats och förutspåtts. / <p>Ytterligare forskningsfinansiär: Kempestiftelserna</p>

This study developed an informative model of a nasal cavity of a Neanderthal and Anatomically Modern Human (AMH) hybrid based on the morphological measurements and nonmetric features of nonhuman primate hybrids. This study examined morphometric measurements and nonmetric traits of the interior nasal cavity of two species of baboons (olive and yellow) and their first generation hybrids to determine how hybridization affects the internal anatomy of the nasal cavity. The nasal cavity was chosen because the nasal cavities of Neanderthals and AMH are recognized as uniquely different in size and shape. This study found that functionally different regions within the baboon nasal cavity are altered in size and shape in response to hybridization. Changes in size and shape due to hybridization occurred in three regions, at the rhinion, choana, and mid-nasopharynx. In regions of more complex physiological function, the mid-bony cavity and the posterior nasopharynx, no size or shape response was observed, except a wider lateral recess. Males and females responded differently to hybridization; males showed heterosis and females showed heterosis in most areas, though dysgenesis in the inferior meatus. The opposing male and female trends may contribute to the greater sexual dimorphism observed in hybrids compared to parental taxa. This study found that frequencies of nonmetric traits in the baboon hybrid nasal cavity were no different from frequencies in parental taxa, nor were regional frequency differences observed because anterior and posterior nonmetric traits occurred at the same frequency. However, males expressed a significantly higher frequency of nonmetric traits than females. Assuming Neanderthal and AMH hybrid nasal cavities follow the trends observed in the baboon hybrid model, the Neanderthal and AMH hybrid nasal cavity would have a different shape and larger size at the rhinion, choana, and mid-nasopharynx, while the mid-bony cavity and posterior nasopharynx remained unchanged compared to parental taxa. However, because Neanderthals and AMH have been diverged for a longer time period, the traits of the nasal cavity may be very different in parental taxa due to adaptations to local conditions, which may result in hybrids with traits from one parent or the other. Further, an analysis of different hybridization scenarios between Neanderthals and AMH, based on observed hybridization in baboons and paleoanthropological evidence, suggests rapid gene swamping of the Neanderthal population by AMH during hybridization, as other authors have also concluded.

Hyperthermophilic proteins are of great interest in both the academic and industrial world in understanding how these proteins are capable of retaining their biological activity under such harsh environmental conditions. This thesis studies a tetrabrachion stalk domain from Staphylothermus marinus, know as Right Handed Coiled Coil (RHCC). This protein is of interest due to its extreme thermostability and its affinity for heavy metals. We aim to better understand the reason for the extreme thermal stability of the protein and to take advantage of the proteins affinity for heavy metals with a view to developing a novel approach to bioremediate Hg2+, a major environmental pollutant. Our results clearly indicated that the protein is more thermostable in alkaline conditions in comparison to acidic conditions. This observation can be explained by careful inspection of the high resolution structure. Our data also clearly show that RHCC is able to bind ionic mercury compounds such as mercury nitrate and dipotassium mercury iodide.

An experimental study has been performed to investigate the condensation on the inner surface of open cavities located on horizontal and vertical surfaces of a refrigerator to simulate ice dispensers, water dispensers, electronic display slots, and door handles, etc. Cavity size, cavity depth and insulation thickness were variable parameters. Cavities were located on fresh food and freezer compartments to study two different boundary conditions. Level of condensation was put into a scale based on visual observation for condensed water droplets on the cavity surface. As a practical tool for design engineers, insulation thickness was plotted as a function of cavity depth indicating the level of condensation. Similar cavity geometries were tested on both freezer and fresh food compartments. Aluminum foil attached behind the inner surface of a cavity located on the fresh food door helped to decrease the level of condensation significantly. However, condensation can not be avoided for the cavities located on the freezer compartment deeper than critical values. Forming radius at the corners and on the edges of cavities decreased condensation on these regions. The effects of air circulation on condensation inside and outside the refrigerator were also investigated for some cavities. Particle Image Velocimetry (PIV) method was used to visualize non-disturbed air flow pattern over the cavity and at the cavity opening. High convective heat transfer at the cavity center was strongly associated with relatively high air velocity. Temperature distribution and flow pattern were analyzed by a CFD Programme. Condensation due to relatively low temperatures at the corners and on the edges was associated with conductive heat transfer in multiple directions and insufficient air circulation on these regions.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 44-46). Also available on the World Wide Web.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--University of Michigan, 1970.

Thesis (M.S.)--University of Michigan, 1969.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (doctoral)--Karolinska Institutet, Stockholm, 2003. / Added t.p. with thesis statement inserted. Includes bibliographical references.