Supraglacial lakes in the ablation zone of the Greenland Ice Sheet (GrIS) often drain rapidly (in hours to days) by hydraulically-driven fracture (“hydrofracture”) in the summer. Hydrofracture can deliver large meltwater volumes to the ice-bed interface and open-up surface-to-bed connections, thereby routing surface meltwater to the subglacial system, altering basal water pressures and, consequently, the velocity profile of the GrIS. The study of rapidly draining lakes is thus important for developing coupled hydrology and ice-dynamics models, which can help predict the GrIS’s future mass balance. Remote sensing is commonly used to identify the location, timing and magnitude of rapid lake-drainage events for different regions of the GrIS and, with the increased availability of high-quality satellite data, may be able to offer additional insights into the GrIS’s surface hydrology. This study uses new remote-sensing datasets and develops novel analytical techniques to produce improved knowledge of rapidly draining lake behaviour in west Greenland over recent years. While many studies use 250 m MODerate-resolution Imaging Spectroradiometer (MODIS) imagery to monitor intra- and inter-annual changes to lakes on the GrIS, no existing research with MODIS calculates changes to individual and total lake volume using a physically-based method. The first aim of this research is to overcome this shortfall by developing a fully-automated lake area and volume tracking method (“the FAST algorithm”). For this, various methods for automatically calculating lake areas and volumes with MODIS are tested, and the best techniques are incorporated into the FAST algorithm. The FAST algorithm is applied to the land-terminating Paakitsoq and marine-terminating Store Glacier regions of west Greenland to investigate the incidence of rapid lake drainage in summer 2014. The validation and application of the FAST algorithm show that lake areas and volumes (using a physically-based method) can be calculated accurately using MODIS, that the new algorithm can identify rapidly draining lakes reliably, and that it therefore has the potential to be used widely across the GrIS to generate novel insights into rapidly draining lakes. The controls on rapid lake drainage remain unclear, making it difficult to incorporate lake drainage into models of GrIS hydrology. The second aspect of this study therefore investigates whether various hydrological, morphological, glaciological and surface-mass-balance controls can explain the incidence of rapid lake drainage on the GrIS. These potential controlling factors are examined within an Exploratory Data Analysis statistical technique to elicit statistical similarities and differences between the rapidly and non-rapidly draining lake types. The results show that the lake types are statistically indistinguishable for almost all factors, except lake area. It is impossible, therefore, to elicit an empirically-supported, deterministic method for predicting hydrofracture in models of GrIS hydrology. A frequent problem in remote sensing is the need to trade-off high spatial resolution for low temporal resolution, or vice versa. The final element of this thesis overcomes this problem in the context of monitoring lakes on the GrIS by adapting the FAST algorithm (to become “the FASTER algorithm”) to use with a combined Landsat 8 and Sentinel-2 satellite dataset. The FASTER algorithm is applied to a large, predominantly land-terminating region of west Greenland in summers 2016 and 2017 to track changes to lakes, identify rapidly draining lakes, and ascertain the extra quantity of information that can be generated by using the two satellites simultaneously rather than individually. The FASTER algorithm can monitor changes to lakes at both high spatial (10 to 30 m) and temporal (~3 days) resolution, overcoming the limitation of low spatial or temporal resolution associated with previous remote sensing of lakes on the GrIS. The combined dataset identifies many additional rapid lake-drainage events than would be possible with Landsat 8 or Sentinel-2 alone, due to their low temporal resolutions, or with MODIS, due to its inferior spatial resolution.

The doctor thesis deals about the influence of zinc coating morphology on limit conditions formability of a thin sheet metal. In the introduction of the thesis is discusesed about current problems searching the most suitable morphology of the steel sheet metals, a method of appliing to the zinc sheet metal. The hot dip zinc coating is discussed in next chapter, the topical knowledges about the influence of the individual factors have some effect to coat calibre and quality. In literary researchs are discussed the concrete technological tests of zinc coating to harder sheet metal forming, the theory of the bend and the basic theory of pressing sheet metal. In following chapter is devoted interpretation selected technological tests, according to that is described behaviour, characteristics, influence of zinc coating formability of basic material and his morphology.

Cone-sheet swarms are magmatic sheet intrusions and part of volcanic plumbing systems and are pathways for magma to the Earth’s surface, where they feed volcanic eruptions. The analysis of cone-sheets provides information on the geometry of the magmatic plumbing system of a volcano and allows to understand processes and dynamics of magma transport. This is important to interpret information during a volcanic crisis and to help reduce risks to humans and infrastructure. In order to create a realistic model, the structure and shape of cone-sheet complexes can be reconstructed in three-dimensional space. Most cone-sheet swarms are not sufficiently exposed to allow such a reconstruction. The Tejeda cone-sheet swarm on Gran Canaria (Canary Islands, Spain), however, is an excellent location to study a cone-sheet complex in great detail, as it is exposed over 15 kmhorizontally and 1000 m vertically. This allows to determine its geometry in 3D space. The felsic deposits of the Miocene Tejeda caldera were intruded by cone-sheets between 11.7 and 7.3 Ma. Schirnick et al. (1999) assumed straight cone-sheets, based on 2D projections, and suggested that the Tejeda cone-sheet swarm is formed by a stack of uniformly dipping, parallel intrusive sheets that converge towards a common, static, laccolith-like source, forming a concentric structure around acentral axis that has the geometry of a truncated cone. This hypothesis was tested in this study, using structural data from Schirnick (1996) as well as additional data collected in the field. Using the software Move™, the extensive data set was visualized and projected in three dimensional space. The underlying magmatic source of the cone-sheets was reconstructed using two different approaches, with the first one based on sets of cross-sections to select intersection points, following an approach prognosed by Burchardt et al. (2013a). To improve the quality of the reconstruction of the magma chamber, a second method was developed using geometric calculations in MATLAB. The results indicate that individual cone-sheets are straight with parallel to slightly fanning dips, which can be steeper in the central part of the cone-sheet complex. They converge towards a common centre, creating a sub-spherical geometry of the source of the cone-sheet complex. Comparison of the two approaches used for the magma chamber reconstruction indicate that the second approach (geometric calculations) produces less uncertainties in data interpretation. The modelling results lead to the proposition of a dynamic model for the emplacement of the Tejeda cone-sheet complex. Cone-sheets would start to intrude from a reservoir situated at about 4500m below sea level that became successively shallower with time. / Inverterade koniska intrusionssvärmar är en del av det underjordiska vulkaniska systemet som möjliggör vägar för magma till jordens yta, där de livnär vulkaniska utbrott. Genom analys av inverterade koniska intrusioner kan information om geometrin hos magmatiska system erhållas vilket gör det möjligt att förstå magmans processer och transportdynamik. Detta är viktigt då det hjälper att tolka information under vulkaniska kriser och kan bidra till att minska risker för människor och infrastruktur. För att skapa en realistisk modell, kan strukturer och former av komplexa inverterade koniska intrusionssvärmar rekonstrueras i ett tredimensionellt utrymme. De flesta inverterade koniska intrusionssvärmar är inte tillräckligt blottade på jordens yta för att möjliggöra en sådan rekonstruktion.Tejedas inverterade koniska intrusionssvärm på Gran Canaria (Kanarieöarna, Spanien) är dock utmärktbelägen för att studera ett inverterat koniskt intrusionskomplex i detalj, detta då den är blottad i över 15 km horisontell och 1000 m i vertikal utsträckning. Detta gör det möjligt att bestämma dess geometrii tre dimensioner. De felsiska avlagringarna av den Miocena Tejeda kalderan blev intruderade av inverterade koniskaintrusioner mellan 11,7 och 7,3 Ma. Schirnick et al. (1999) antog att dessa intrusioner var raka, baseratpå 2D-projektioner, och föreslog att Tejedas inverterade koniska intrusionssvärm bildades som enlikformigt stupande stapel av parallella intruderande plan som konvergerar mot en gemensam, statiskoch lakkolitisk källa, vilken i sin tur bildar en koncentrisk struktur runt en central axel med samma geometri som en inverterad stympad kon. Denna hypotes undersöktes i detta arbete, med hjälp avstrukturell data från Schirnick (1996) samt ytterligare data insamlat från fält. Den omfattande datamängden visualiserades och projicerades i tre dimensioner med hjälp av mjukvaran Move™. Denunderliggande magmatiska källan till det inverterade koniska intrusionskomplexet rekonstruerades medhjälp av två olika metoder, den första är baserad på tvärsnitt där planens skärningspunkter kan studeras, följt av ett tillvägagångssätt framställt av Burchardt et al. (2013a). För att förbättra kvalitén pårekonstruktionen av magmakammaren utvecklades en andra metod med hjälp av geometriskaberäkningar i MATLAB. Resultaten tyder på att enskilda inverterade koniska intrusioner är raka med parallellt till svagt flacktstupning, vilka kan vara brantare mot den centrala delen av komplexet. De konvergerar mot ettgemensamt centrum, vilket skapar en sub-sfärisk geometri hos källan till det inverterade koniskaintrusionskomplexet. Jämförelse av de två metoderna som används för magmakammarens rekonstruktion tyder på att denandra metoden (geometriska beräkningar) ger färre osäkerheter i tolkningen. Modelleringsresultatettyder på en dynamisk modell för bildningen av Tejedas inverterade koniska intrusionskomplex. Enligtdessa resultat skulle de inverterade koniska intrusionerna till en början ha utgått från en reservoarungefär 4500 m under havsytan som med tiden förflyttade sig mot grundare nivåer.

Correct layering (lamination) of neurons in the central nervous system (CNS) is critical for the tissue functionality. Neuronal lamination is established during development, when the majority of neurons have to move from their birthplace to the appropriate layer, where they function. Therefore, to grasp the logic of CNS development, it is essential to understand the kinetics and modes of the variety of neuronal translocation events. Most of our knowledge about neuronal translocation has been gained using fixed tissue or ex vivo imaging, which is not ideal for such a dynamic process heavily dependent on the surrounding environment. To avoid these limitations, I combined translucent zebrafish embryos with light sheet fluorescence microscopy, which together enabled gentle in toto imaging of neuronal translocation. I studied the translocation of retinal ganglion cells (RGCs) across the developing zebrafish retina. RGCs are the first neurons that differentiate in the vertebrate retina and are born in a proliferative zone at the retinal apical side. From here, they move basally, spanning the complete apico-basal length of the tissue. They are destined to occupy the most basal layer, where their axons form the optic nerve. Although it was described that RGCs move their soma while being attached to both apical and basal sides of the retina, the kinetics and cell biological mechanisms of somal translocation remained unknown. Extracting single cell behavior of RGCs from high-resolution movies of their translocation allowed for quantitative analysis of RGC movement. I revealed that RGCs cross the retina in less than two hours in a directionally persistent manner. The movement of RGC soma is a cell autonomously generated process, which requires intact microtubules and actin-dependent basal attachment of cells for speed and efficiency. Unexpectedly, interference with somal translocation leads to a shift towards a multipolar migratory mode, previously not observed for RGCs, in which they temporarily lose both apical and basal attachment and apico-basal polarity. The multipolar mode is overall slower and less directionally persistent, but still allows RGCs to reach the basal retina. However, when RGC translocation is inhibited completely, they differentiate ectopically in the center of the retina, which in turn triggers the formation of ectopic layers of later born neurons. These results highlight the importance of establishing the basal layer of ganglion cells for ensuing retinal lamination. Overall, I generated important advances in the understanding of neuronal translocation and lamination, which might be relevant for other parts of the CNS.

Ressonância Magnética (RM) é uma técnica bastante versátil, pois é utilizada em muitas áreas de pesquisa, como biologia, física, química, engenharia e medicina. Apesar disso, constitui-se uma desvantagem o alto custo do equipamento e suas restrições físicas para alguns experimentos. Para reduzir essas desvantagens, o grupo de pesquisadores do CIERMag está desenvolvendo um equipamento de RMN multipropósito e, para complementá-lo, este trabalho vem desenvolver um subsistema non-real-time que gerencia os dispositivos periféricos de um experimento. Foi proposta uma rede de dispositivos que é controlada por um Raspberry Pi como elemento central, o qual está conectado ao terminal computadorizado do sistema através de uma rede local (Local Area Network - LAN) via Ethernet e conectado aos dispositivos periféricos via Serial Peripheral Interface (SPI). Com o objetivo de ser possível gerenciar qualquer tipo de dispositivo, foi desenvolvido um conjunto de parâmetros baseado no Transducer Electronic Data Sheet (TEDS), definido no padrão IEEE 1451, de modo que cada dispositivo, normalmente um transdutor, possui seu próprio. Foram elaboradas duas interfaces de software: uma desenvolvida em Python e a outra uma interface web HTML. Ambas as interfaces possuem as mesmas funcionalidades: editor e gerenciador de TEDS, visualização gráfica de medidas dos sensores e interface para os atuadores. / Magnetic Resonance (MR) is a very versatile technique, since it is used in many research areas such as biology, physics, chemistry, engineering and medicine. Despite this, the cost of the equipment and its physical restrictions in some experiments constitute a serious drawback. To minimize these problems, the CIERMag research team is developing multipurpose MR equipment and, to complement this equipment, this work develops a non-real-time subsystem that manages the peripheral devices of the experiment. It was proposed a network of devices controlled by a Raspberry Pi as its central element, which is connected to the terminal computer of the system. The protocol adopted for this was Ethernet via Local Area Network (LAN); communication with peripheral transducers was performed with the Serial Peripheral Interface (SPI). With the objective to be able to manage any type of device, we created parameter sets based on Transducer Electronic Data Sheet (TEDS), defined in the IEEE 1451 standard, so each device, normally a transducer, has its own parameter set. We created two software interfaces: one developed with Python and the other is a HTML web interface. Both have the same functionalities: a TEDS editor and manager, a graphical visualization of sensor measurements and also an actuator interface.

This thesis aims at studying the breakup of swirling liquid sheets discharging from the outer orifice of gas centered swirl coaxial atomizers. Such atomizers are considered as propellant injection systems for semi-cryogenic liquid rocket engines. A gas centered swirl coaxial type atomizer discharges an annular swirling liquid sheet which is atomized by a gaseous jet issuing from the central orifice of the atomizer. The primary objectives of this work were to understand the fluid dynamic interaction process between the outer liquid sheet and the central gas jet and its role on the breakup process of the liquid sheet. Cold flow experiments were carried out by constructing custom made gas centered swirl coaxial atomizers. Two different atomizer configurations with varying swirl effect were studied. The jets were injected into ambient atmospheric air medium with tap water and air as experimental fluids. The flow conditions were described in terms of Weber number (Wel) and Reynolds number (Reg) for liquid sheet and the air jet respectively. Spray images were captured by employing an image acquisition system comprising a high resolution digital camera and a strobe lamp. The captured spray images at different combinations of Wel and Reg were analyzed to extract quantitative measurements of breakup length (Lb), spray cone angle (θs), spray width (SW) and two-dimensional surface profile of liquid sheets. Quantitative analysis of the variation of Lb with Reg with different values of Wel suggested that low inertia liquid sheets undergo an efficient breakup process. High inertia liquid sheets ignore the presence of central air jet at lower values of Reg however undergo air jet breakup at higher values of Reg. Qualitative analysis of experimental observations revealed that the entrainment process, established between the inner surface of the liquid sheet and the boundary of central jet, triggers the air assisted sheet breakup by drawing the liquid sheet closer to the spray axis. The entrainment process may be developing corrugations on the surface of liquid sheet which promotes the production of thick liquid ligaments from the sheet surface. The level of surface corrugations on the liquid sheet, quantified by means of tortuosity of liquid sheet profile, increases with increasing Reg. Limited studies on the effect of variation swirl intensity on the air assisted breakup process of liquid sheets did not show any significant influence for the atomizers examined in the present work.

Under höstterminen 2013 har Stefan Erlandsson och Louise Andersson, designingenjörsstudenter på Högskolan i Skövde, utfört ett produktutvecklingsprojekt i samarbete med entreprenören Lars Willebrand. Målsättningen för projektet var att utveckla ett lyftverktyg som ska komplettera Willebrands produktserie bestående av; travers, svängkran, plåtbyrå och lyftverktyg. Lyftverktyget ska vara anpassat för att användas i kombination med en plåtbyrå, vilket innebär att det kommer användas till att lyfta material från höga och låga höjder. Lyftverktyget måste därmed konstrueras i syfte att underlätta för användaren och undvika arbetsskador som kan uppstå vid dessa lyft. Lyftverktyget ska även kunna anpassas till kunder som endast avser att lyfta skivformade produkter i midjehöjd. Projektet inleds med en förstudie där mycket fokus läggs på ergonomi och användaren. Förstudien har gjorts genom fördjupning i relevant litteratur, kontakt med industriföretag och genom att analysera konkurrerande lyftverktyg. Resultatet från förstudien har sammanfattats till en kravspecifikation som legat till grund för konceptframtagningen. Konceptframtagningen har skett stegvis, där lyftverktygets huvudfunktioner utvecklats var för sig. De funktioner som utvecklats är justering av sugkopparnas position, manövrering och lyft vid hög/låg höjd. Alternativa lösningar har tagits fram och utvärderats för att hitta den lämpligaste lösningen på varje enskild funktion. När de bästa lösningarna hade tagits fram sattes dessa samman till ett slutgiltigt koncept. Det slutgiltiga konceptet har analyserats och detaljutvecklats. För att underlätta tillverkning och tillgodose kundens behov har många av lyftverktygets delar anpassats och ritats om. För att säkerställa att lyftverktyget lever upp till kravspecifikationen har hållfasthetsberäkningar och en antropometrisk analys genomförts. Projektets process och resultat sammanfattades och diskuterades. Slutligen gavs förslag på rekommendationer för fortsatt utveckling av lyftverktyget. / During the second semester of 2013, product design engineering students Stefan Erlandsson and Louise Andersson have been involved in a project in cooperation with entrepreneur Lars Willebrand. The main objective of this project has been to develop a lifting tool for sheet materials. The lifting tool is one of four different products developed by Lars Willebrand. The line of products also includes an overhead crane, a slewing crane and a storage drawer for metal sheets, which are already fully developed and ready for production. The purpose of this lifting tool is to be used along with the storage drawer which means that is has to be optimised for lifting sheet materials from different heights. This means that the lifting tool has to be designed with regards to the users working postures. Human factors such as ergonomics have to be taken into account as well. The initial part of the project is a pre-study with focus on ergonomics and human factors. This pre-study included a study in relevant literature, contact with a manufacturing company and an analysis of the possible competitor’s lifting tools. The results from the pre-study have further been used to define the specification of requirements, which is the foundation for the concept development. The concept development has undergone a number of different phases. All of the lifting tool’s main functions were broken down and developed individually. The functions were as follows; adjustment of the suction cups, lifting from different heights and handling. The most suitable solution for each main function were chosen and assembled into one final concept. The final concept has been analysed and further developed in order to please the employer and the users of the lifting tool. Some details in the design have been changed in order to ease the manufacturing of the lifting tool. To ensure that the final concept matches the specification of requirements, strength calculations and FEM analysis have been made and anthropometrical measurements have been taken into account. The final chapters include a discussion and recommendations for further development of the lifting tool.

No description available.

Le transport sédimentaire contrôle l'évolution morphologique des rivières, l'érosion du littoral et l'équilibre des écosystèmes. Il constitue également un facteur de risque pour les populations et les infrastructures. Le sheet-flow, ou charriage intense, est un régime de transport sédimentaire qui s'établi lors de crues dans les fleuves et les rivières ou lors du déferlement des vagues littorales sur les plages sableuses. Le fort taux de transport associé à ce régime le rend très morphogène et une bonne compréhension des processus physiques impliqués est fondamentale pour prédire la morphodynamique. Cependant, les interactions granulaires et les fluctuations turbulentes, qui sont les principaux mécanismes à l'œuvre dans ce phénomène, constituent des verrous scientifiques pour la modélisation du régime de sheet-flow. Cette déficience s'explique essentiellement par le manque de données expérimentales haute résolution. Partant de ce constat, l'objectif de la thèse est de proposer un modèle diphasique et un dispositif expérimental haute résolution permettant de mieux caractériser les mécanismes impliqués. indent Dans un premier temps, le modèle diphasique est présenté et les résultats obtenus sont confrontés aux données de la littérature. L'analyse des résultats montre que la rhéologie des écoulements granulaires denses ($mu(I)/phi(I)$) et l'approche de longueur de mélange utilisées sont des fermetures appropriées pour reproduire les principales caractéristiques du régime de sheet-flow pour une large gamme d'écoulements et de propriétés sédimentaires. La deuxième partie de la thèse est consacrée à la mise en place d'un dispositif expérimental capable de fournir des mesures instantanées de vitesse et de concentration en régime de sheet-flow uniforme. Dans la troisième partie les grandeurs moyennes sont analysées pour décrire la structure verticale de l'écoulement. Les résultats obtenus montrent qu'une formulation en longueur de mélange et un profil de Rouse permettent de décrire la contrainte turbulente et le profil de concentration dans la suspension à condition de fortement modifier le paramètre de von Karman ($kappa approx 0.2$) et le nombre de Schmidt ($sigma_s=0.44$). La rhéologie frictionnelle ($mu(I)/phi(I)$) et la théorie cinétique des écoulements granulaires prédisent qualitativement le comportement observé, mais échoue à reproduire quantitativement les mesures. Le lien étroit existant entre les structures cohérentes turbulentes et la dynamique du lit sédimentaire illustre l'importance des fluctuations et de l'intermittence de l'écoulement. Ce couplage pourrait expliquer l'écart observé entre le comportement prédit par les modèles de contraintes inter-granulaires et les mesures expérimentales. Finalement, la comparaison des analyses statistiques en régime de sheet-flow et en écoulement sur fond fixe rugueux permet de montrer que l'énergie cinétique turbulente est peu affectée par la présence des sédiments mais que le niveau de corrélation entre fluctuations horizontales et verticales est sensiblement diminué, impliquant une diminution de la longueur de mélange et de la viscosité turbulente. Une augmentation significative de la rugosité équivalente induite par le lit mobile est aussi observée. / Sediment transport controls river morphological evolution, coastal erosion and ecosystem equilibrium. It represents a risk factor for populations and infrastructures. The sheet-flow, or intense bed-load, is a regime of sediment transport occurring during river floods or in the coastal wave breaking region above sandy beaches. The large amount of sediment transported in this regime is the main source for morphological evolution in our natural systemswater bodies. A good understanding of the underlying physical processes is a pre-requisite for accurate morphodynamic predictions. However, particle-particle interactions and turbulent flow interactions, which are the main driving mechanisms in this problem, constitute the scientific bottlenecks for sheet-flow modelling. This deficiency is mainly caused by the lack of high resolution experimental data. Based on this observation, the objective of the present thesis is to propose a novel two-phase model and to generate a new set of high resolution experiment data to improve process based sheet-flow modelling. indent First, the two-phase flow model is presented and the obtained results are compared with data from the literature. The result analysis has shown that the dense granular flow rheology ($mu(I)/phi(I)$) combined with a turbulent mixing length concept predicts the main sheet flow characteristics over a wide range of flow and sediment properties. Secondly, the experimental set up providing high-rate measurements of velocity and concentration under a uniform sheet-flow regime is presented. Third, the measured mean flow quantities are analysed to describe the vertical structure of the flow. The obtained results show that a mixing length formulation and a Rouse profile allow to describe the turbulent stress and the concentration profiles in the turbulent suspension layer, provided that the von Karman parameter and the Schmidt number are modified ($kappa approx 0.2$ and $sigma_s=0.44$). The frictional rheology ($mu(I)/phi(I)$) and the kinetic theory of granular flows predict qualitatively the observed behaviour but fail to reproduce measurements quantitatively. The observed link between the turbulent coherent structures and the bed dynamic illustrates the importance of flow fluctuations and intermittency. This coupling could be responsible for the discrepancy found between the predictions from the intergranular stresses models and the measurements. Finally, the comparison between the statistical analysis performed for a sheet-flow regime and for a clear water flow over a rough fixed bed demonstrates that the turbulent kinetic energy is weakly affected by the presence of sediments whereas the turbulent correlation level between horizontal and vertical fluctuations is significantly reduced, leading to a decrease of both the mixing length and the turbulent eddy viscosity. An increase of the equivalent roughness height induced by the moving bed is also observed.

In the past two decades, Fluorescence microscopy has imparted tremendous impact in Biology and Imaging. Several super-resolution Fluorescence imaging techniques (e.g. PALM, STED, STORM, 4Pi and structured illumination) have enabled diff raction-unlimited imaging. But high resolution is limited to a depth of few tens of microns. Thus, deep tissue imaging and simultaneous volume imaging have become a highly sought after feature in Fluorescence microscopy. The research work in this thesis address these issues by using spatial filtering techniques to tailor the point spread function (PSF) which uniquely characterizes the optical sys-tem. The advantage of this approach lies in the fact that intricate details about the focal region can be computed and designed with the help of well established theory and experimentation. In particular, this technique was applied to both spherical and cylindrical lenses. The former was used to generate Bessel-like, non-diffracting beams which demonstrated the ability to penetrate deep inside tissue-like media and thereby yielded an imaging depth of nearly 650μm as compared to about 200μm for a state-of-the-art confocal microscope. The latter gave rise to light-sheet and it's extended version that is ideal for planar imaging at large penetration depths. Another development is the generation of multiple light-sheet illumination pattern that can simultaneously illuminate several planes of the specimen. The proposed multiple light-sheet illumination microscopy (MLSIM) technique may enable volume imaging in Fluorescence microscopy. The first two chapters of this thesis are introductory in nature and provides a general overview of the principles of Fluorescence microscopy and three state-of-the-art Fluorescence imaging techniques; namely confocal, multi-photon and light-sheet based microscopy. Confocal microscopes are widely considered as a standard tool for biologists and this discussion shows that even though they have made signi ficant contributions in the fields of biophysics, biophotonics and nanoscale imaging, their inability to achieve better penetration depth has prevented their use in thick, scattering samples such as biological tissue. The system PSF of a confocal microscope broadens as it goes deeper in-side a scattering sample resulting in poor-resolution thereby destroying the very concept of high resolution, noise-free imaging. Additionally, confocal microscopy suffers from in-creased photo-bleaching due to o -layer (above and below the focal plane) excitation and low temporal resolution since it requires point-by-point scanning mechanism. On the other hand, multi-photon microscopy offers several advantages over confocal microscopy such as reduced photo-bleaching and inherent optical sectioning ability, however, it still lacks in providing high temporal resolution. Light-sheet based microscopy have gained popularity in recent years and promises to deliver high spatio-temporal resolution with minimized photo-bleaching. Recently, a considerable amount of research has been dedicated to further develop this promising technique for a variety of applications. The ability to look deeper inside a biological specimen has profound implications. How-ever, at depths of hundreds of microns, several effects (such as scattering, PSF distortion and noise) deteriorates the image quality and prohibits detailed study of key biological phenomenon. Chapter 3 of this thesis describes the original research work which experimentally addresses to this issue. Here, Bessel-like beam is employed in conjugation with an orthogonal detection scheme to achieve imaging at large penetration depth. Bessel beams are penetrative, non-di ffracting and have self-reconstruction properties making them a natural choice for imaging scattering prone specimens which are otherwise inaccessible by other microscopy imaging techniques such as, Widefield, CLSM, 4PI, Structural illumination microscopy and others. In this case such a Bessel-like beam is generated by masking the back-aperture of the excitation objective with a ring-like spatial filter. The proposed excitation scheme allow continuous scanning by simply translating the detection optics. Additionally, only a pencil-like region of the specimen can be illuminated at a given instance thereby reducing premature photobleaching of neighboring regions. This illumination scheme coupled with orthogonal detection shows the ability of selective imaging from a desired plane deep inside the specimen. In such a configuration, the lateral resolution of the illumination arm determines the axial resolution of the overall imaging system. Such an imaging system is a boon for obtaining depth information from any desired specimen layer that includes nano-particle tracking in thick tissue. Experiments performed by imaging the Fluorescent polymer tagged-CaCO3 particles and yeast cell in a tissue-like gel-matrix demonstrates penetration depth that extends up to 650 m. This will advance the field of fluorescence imaging microscopy and imaging. Similar to the ability to observe deep inside a sample, simultaneous 3D monitoring of whole specimens play a vital role in understanding many developmental process in Biology. At present, light-sheet based microscopy is the prime candidate amongst the various microscopy techniques, that is capable of providing high signal-to-background-ratio as far as planar imaging is concerned. Since spatial filtering technique was found to successfully give rise to novel features (such as large penetration depth) in a fluorescence microscope setup, a logical extension would be to implement a similar approach with a light-sheet based microscope setup. These implementations are discussed in Chapter 4 of this thesis where spatial filtering is employed with cylindrical lenses. For facilitating computational and experimental studies, a vectorial formalism was derived to give an explicit computable integral solution of the electric field generated at the focal region of a cylindrical lens. This representation is based on vectorial diffraction theory and further enables the computation of the point spread function of a cylindrical lens. Commonly used assumptions are made in the derivation such as no back-scattering and negligible contribution from evanescent fields. Stationary phase approximation along with the Fresnel transmission coefficients are employed for evaluating the polarization dependent electric field components. Computational studies were carried out to determine the polarization effects and calculate the system resolution. Experimental comparison of light-sheet intensity pro les show good agreement with the theoretical calculations and hence validate the model. This formalism was derived as a first step since it gives the essential understanding of tightly focused E-fields of a high N.A. cylindrical lens systems and thereby helps in further understanding the effect of spatial filtering. As the next step, generation of extended light-sheet for fluorescence microscopy is pro-posed by introducing a specially designed double-window spatial filter at the back-aperture of a cylindrical lens. The filter allows the light to pass through the periphery and center of a cylindrical lens. When illuminated with a plane wave, the proposed filter results in an extended depth-of-focus along with side-lobes which are due to other interferences in the transverse focal plane. Computational studies show a maximum extension of light-sheet by 3:38 times for single photon excitation, and 3:68 times for multi-photon excitation as compared to state-of-art single plane illumination microscopy (SPIM) system and essentially implies a larger field of view. Finally, generation of multiple light-sheet pattern is proposed and demonstrated using a different spatial filter placed at the back aperture of a cylindrical lens. A complete imaging setup consisting of multiple light-sheets for illumination and an orthogonal detection arm, is implemented for volume imaging in fluorescence microscopy. This proposed scheme is a single shot technique that enables whole volume imaging by simultaneously exciting multiple specimen layers. Experimental results confirm the generation of multiple light-sheets of thickness 6:6 m with an inter-sheet spacing of 13:4 m. Imaging of 3 5 m sized fluorescently coated Yeast cells (encaged in Agarose gel-matrix) is per-formed and conclusively demonstrates the usefulness and potential of multiple light-sheet illumination microscopy (MLSIM) for volume imaging. As part of the future scope of the research work presented in this thesis, the Bessel-beam based improved depth microscopy technique may attract applications in particle tracking deep inside tissues and optical injection apart from fluorescence imaging applications. The vectorial formalism derived for cylindrical lens can be used to predict other, complex optical setups involving cylindrical lenses. Extended light-sheet generation proposed in this work by using appropriate spatial filtering with a cylindrical lens, complements the existing and popular selective plane illumination microscopy technique and may facilitate the study of large biological specimens (such as, full-grown Zebra sh and tissue) with high spatial resolution and reduced photobleaching. Finally, the MLSIM technique presented in this thesis may accelerate the field of developmental biology, cell biology, fluorescence imaging and 3D optical data storage.