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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
541

Superposition in the leading edge region of a film cooled gas turbine vane

Anderson, Joshua Brian 04 April 2014 (has links)
The leading edge of a turbine vane is subject to some of the highest temperature loading within an engine, and an accurate understanding of leading edge film coolant behavior is essential to efficient engine design. Although there have been many investigations of the adiabatic effectiveness for showerhead film cooling within the leading edge region, there have been no previous studies in which individual rows of the showerhead were tested with the explicit intent of validating superposition models. For the current investigation, a series of adiabatic effectiveness experiments were performed with a five-row showerhead, wherein each row of holes was operated in isolation. This allowed evaluation of superposition on both the suction side of the vane, which was moderately convex, and the pressure side of the vane, which was mildly concave. Superposition was found to accurately predict performance on the suction side of the vane at lower momentum flux ratios, but not for higher momentum flux ratios. On the pressure side of the vane, the superposition predictions were consistently lower than measured values, with significant under-prediction of adiabatic effectiveness occurring at the higher mass flow rates. Possible reasons for the under-prediction of effectiveness by the superposition model are presented. / text
542

Synthesis and Evaluation of Asymmetric Zinc and Phosphorous Pc Photosensitizers for Mitochondrial Targeted Photodynamic Therapy

Muli, Dominic Kyalo January 2015 (has links)
Cancer remains a global pandemic and is rapidly overtaking other diseases as the no.1 killer in developing nations. Photodynamic therapy (PDT) has been advanced as a minimally invasive cancer therapy. In addition, the emergence of harmful microbes with increasing resistance to drugs has prompted the employment of photodynamic antimicrobial chemotherapy (PACT) as a promising alternative to combat antibiotic resistance. In PDT and PACT, a photosensitizer (dye/drug) upon activation by light transfers energy to molecular oxygen producing singlet oxygen which kills cells. There is increased attention and research into more selective and non-aggregated photosensitizers that will better PDT in treating cancer. This research work is focused on design and synthesis of non-aggregated asymmetric phthalocyanines (dyes) tagged with mitochondrial targeting vehicles to maximize selectivity and photo-killing of tumor cells. Chapter 1 presents a brief review of the current status of PDT and treatment of cancer. The three components of PDT namely, light, oxygen and the photosensitizer, are briefly discussed giving a concise overview of the development of each of them in bettering PDT as an alternative to cancer therapy. Chapter 2 outlines the design, synthesis and characterization of two non-aggregated symmetric ZnPc isomers that have improved water solubility due to incorporation of triethylene glycol groups. The extension of the max absorption to near-IR via non-peripheral substitution on the Pc macrocycle is reported, while comparing the photophysical characteristics of both isomers. Chapter 3 details the improved selectivity of photosensitizers by conjugating ZnPcs to rhodamine B, a delocalized lipophilic cation, which targets the mitochondria of the cell. This conjugation achieved 70% more cell death suggesting that incorporation of rhodamine improved cellular uptake and localization of the photosensitizers which is crucial. Chapters 4 and 5 cover the design, synthesis, characterization, and photodynamic therapy evaluation of ZnPc and phosphorous phthalocyanines. Introduction of phosphorous as an electron deficient central atom promoted a 42 nm bathochromic shift relative to the corresponding ZnPc isomer. Additionally, the effect of peripheral and non-peripheral substitution on phototoxicity of these new compounds is studied and reported. Chapter 5 also gives concluding remarks, and future directions of this work.
543

Ανάπτυξη αναλυτικών τεχνικών για ποιοτικό και ποσοτικό προσδιορισμό πολύμορφων της υδροχλωρικής δονεπεζίλης σε δισκία

Ζήση, Γεωργία 19 August 2014 (has links)
Η υδροχλωρική δονεπεζίλη (Donepezil.HCl, DPZ) είναι ένα φάρμακο που λαμβάνεται για τη θεραπεία της νόσου Altzheimer. Δρα ως ανασολέας της ακετυλοχοληστερινάσης, ενός ενζύμου υπεύθυνου για την καταστροφή του νευροδιαβιβαστή ακετυλοχολίνη, αυξάνοντας το ποσό της ακετυλοχολίνης στον εγκέφαλο. Παρουσιάζει διάφορες κρυσταλλικές μορφές, συμπεριλαμβανομένων δύο ένυδρων, καθώς και μια άμορφη φάση. Τα δισκία Υδροχλωρικής Δονεπεζίλης λαμβάνονται από το στόμα και μπορεί να αποθηκευθούν για κάποιο χρονικό διάστημα πριν χρησιμοποιηθούν. Τα δισκία DPZ ισχύος 10 mg περιέχουν 3.6 % API, ενώ στις περιπτώσεις όπου λαμβάνει χώρα πολυμορφική μετατροπή, η επιμέρους περιεκτικότητα κάθε πολυμόρφου είναι ακόμα μικρότερη. Η ταυτοποίηση και ποσοτική ανάλυση των πολυμόρφων ή ένυδρων μορφών είναι δυνατή μόνο με τη χρήση περίθλασης ακτίνων Χ και δονητικών φασματοσκοπικών τεχνικών. Λόγω του μικρού ποσοστού της δραστικής ουσίας στα δισκία και της πιθανής παρουσίας περισσοτέρων του ενός πολυμόρφου αλλά και του μεγάλου σχετικά ορίου ανίχνευσης αυτών των τεχνικών η ταυτοποίηση και ποσοτική ανάλυση είναι μια αναλυτική πρόκληση. Στην παρούσα εργασία έγινε προσπάθεια ταυτοποίησης των κρυσταλλικών μορφών του DPZ σε δισκία και έλεγχος της σταθερότητάς τους μετά από διάφορες διαδικασίες παρασκευής των δισκίων, καθώς και μετά από αποθήκευση σε διάφορες συνθήκες υγρασίας και θερμοκρασίας, χρησιμοποιώντας τις πειραματικές τεχνικές XRD, FT-IR και FT-Raman. Παρατηρήθηκε ότι η προέλευση του API, οι συνθήκες αποθήκευσης και κυρίως η μέθοδος παρασκευής των δισκίων επηρεάζουν τη σταθερότητα των φαρμακευτικών σκευασμάτων. Με στόχο τη διερεύνηση της δυνατότητας ανάπτυξης ποσοτικών αναλυτικών μεθόδων προσδιορισμού των πολυμόρφων Ι και ΙΙΙ του DPZ σε δισκία, οι παραπάνω τεχνικές χρησιμοποιήθηκαν για τον υπολογισμό των ορίων ανίχνευσης των δύο πολυμόρφων (0.35% κ.β. για το πολύμορφο Ι και 0.44 % κ.β. για το πολύμορφο ΙΙΙ με την τεχνική Raman, 0.95% κ.β. για το πολύμορφο Ι και 1.3 % κ.β. για το πολύμορφο ΙΙΙ με την τεχνική XRD, 1.2% κ.β. για τη μορφή Ι και 1.0 % κ.β. για τη μορφή ΙΙΙ με την τεχνική IR, όπως προέκυψαν μετά από στατιστική επεξεργασία των πειραματικών δεδομένων των διαφόρων τεχνικών), καθώς και για τον ποσοτικό τους προσδιορισμό. Η τεχνική Raman φαίνεται να μπορεί χρησιμοποιηθεί για ποσοτική ανάλυση των πολυμόρφων Ι και ΙΙΙ του DPZ σε δισκία, ενώ επιπλέον η ποσοτική μέθοδος που παρουσιάσθηκε εδώ είναι απλή και μη καταστροφική για τα δείγματα. Η μέθοδος XRD μπορεί πιθανόν να χρησιμοποιηθεί για την ποσοτική ανάλυση δισκίων DPZ, με μεγαλύτερο όμως σφάλμα σε σύγκριση με την τεχνική Raman, ενώ η μέθοδος FT-IR ATR, παρέχει τα λιγότερο καλά ποσοτικά αποτελέσματα, ακόμα και στην περίπτωση που το δισκίο περιέχει αποκλειστικά το ένα από τα δύο πολύμορφα. Τέλος, με στόχο την ερμηνεία των φασμάτων δόνησης που καταγράφησαν στην παρούσα εργασία, υπολογίστηκαν η σταθερή δομή του μορίου της Δονεπεζίλης και της ένυδρης Δονεπεζίλης (με ένα μόριο νερού ανά μόριο Δονεπεζίλης) και τα φάσματα δόνησης (IR και Raman) με τις μεθόδους Hartree-Fock ab-initio και DFT (Density Functional Theory) και χρήση του υπολογιστικού πακέτου Gaussian09. / Donepezil hydrochloride (DPZ) is a medication used to treat Altzheimer’s disease. It acts as an inhibitor of acetylcholisterinase, an enzyme responsible for the destruction of the neurotransmitter acetylcholine, thus increasing the level of acetylcholine in the brain. As most of the pharmaceutical solids, DPZ exhibits polymorphism. Donepezil hydrochloride has different crystalline forms, including two hydrates, as well as an amorphous phase. DPZ is available for oral administration in tablets which can be stored for some time before use. In the present study, an effort was made to identify the crystal form of DPZ in tablets, as well as to test its stability against time, temperature and humidity, after various manufacturing processes, using XRD, FT-IR and FT-Raman techniques. The data showed that the origin of the API, the storing conditions and mainly the manufacturing process of the tablets affect the stability of the API. Quantitative determination of polymorphs I and III of DPZ in tablets was also attempted using the above experimental methods. Calibration models were constructed and applied in DPZ tablets. The detection limits of polymorphs I and III of DPZ for each technique, derived after statistical treatment of the experimental data, were calculated. Raman spectroscopy exhibited the lower detection limit (0.35 weigh % for polymorph Ι and 0.44 % weigh % for polymorph ΙΙΙ) compared with XRD (0.95% weigh % for polymorph Ι and 1.3 % weigh % for polymorph ΙΙΙ) and IR spectroscopy (1.2% weigh % for polymorph Ι and 1.0 % weigh % for polymorph ΙΙΙ). The data suggest that Raman spectroscopy could be applied to quantify polymorphs I and III in DPZ tablets; moreover, the Raman quantitative method presented in this work is simple and non-destructive for the tablets. The application of the X ray diffraction method for the quantitative analysis of polymorphs I and III in tablets yielded larger errors compared with Raman spectroscopy, while the FT-IR ATR technique yielded poor quantitative results, even in the case that only one polymorph was present in DPZ tablets. Finaly, in order to facilitate the assignment of the vibrational spectra recorded in this study, the optimized structure and the vibrational spectra (IR and Raman) of Donepezil and Donepezil hydrate (Donepezil:H20 = 1:1) molecules were calculated at the Hartree-Fock and DFT (Density Functional Theory) level of theory using the Gaussian 09 program package. The weigh % of the API in the tablets containing 10 mg of DPZ is 3.6 %. In cases where two or more polymorphs are present, the weigh % of each polymorphic form is lower. The difficulty in the identification and quantification of the crystal phase of DPZ is stemming from the small percentage of the API in the tablets, the considerable overlapping of DPZ XRPD patterns and IR and Raman spectra of the polymorphs and the excipients and the availability of various polymorphs.
544

THE INTERACTION BETWEEN THE INTRACLUSTER MEDIUM AND THE CLUSTER STELLAR CONTENT

Sivanandam, Suresh January 2010 (has links)
We study specific aspects of the relationship between the stellar content and the intracluster media (ICM) of galaxy clusters. First, we attempt to solve the long-standing difficulty in explaining the highly enriched ICM by including a previously unaccounted for stellar component: the intracluster stars. To determine the relative contributions of galactic and intracluster stars to the enrichment of the intracluster medium (ICM), we present X-ray surface brightness, temperature, and Fe abundance profiles for a set of twelve galaxy clusters for which we have extensive optical photometry. Assuming a standard IMF and simple chemical evolution model scaled to match the present-day cluster early-type SN Ia rate, the stars in the brightest cluster galaxy (BCG) plus the intracluster stars (ICS) generate 31⁺¹¹₋₉%, on average, of the observed ICM Fe within r₅₀₀(∼ 0.6 times r₂₀₀, the virial radius). Because the ICS typically contribute 80% of the BCG+ICS Fe, we conclude that the ICS are significant, yet often neglected, contributors to the ICM Fe within r₅₀₀. However, the BCG+ICS fall short of producing all the Fe, so metal loss from stars in other cluster galaxies must also contribute. By combining the enrichment from intracluster and galactic stars, we can account for all the observed Fe. These models require a galactic metal loss fraction (0.84(−0.14)^(+0.11)) that, while large, is consistent with theoretical models of Fe mass not retained by galactic stars. The SN Ia rates, especially as a function of galaxy environment and redshift, remain a significant source of uncertainty in further constraining the metal loss fraction. Second, we study the effects of ram-pressure stripping on infalling galaxies using a warm molecular hydrogen (H₂) as a tracer by carrying out a Spitzer infrared spectrograph (IRS) survey of four galaxies with signatures of ram-pressure stripping. We have discovered two galaxies, ESO 137-001 and NGC 4522, with warm H₂ tails stretching 20 kpc and 4 kpc in length, respectively. In the case of ESO 137-001 where we measure a warm H₂ mass loss rate of ∼ 2 − 3 M⊙ yr⁻¹, we estimate that the galaxy will lose all of its gas in a single pass through the cluster core. Strong warm H₂ emission is detected in one other galaxy, CGCG 97-073, which a region within its tail that is mainly dominated by H₂ emission. The warm H₂ observed in these three galaxies share similar temperature and column density properties with warm H₂ masses ranging from 10⁶ − 10⁸ M⊙. From a comparison with the SINGS warm H₂ sample, our results indicate that these galaxies experiencing significant ram-pressure stripping show anomalously high warm H₂ emission that cannot be explained purely from star formation. This adds credence to the hypothesis that H₂ within these galaxies is being shock-heated from the interaction with the ICM. We also discover that stripping of warm and hot dust, as measured at 8 μm and 24 μm, is a common feature of the galaxies observed in our sample. In the case of NGC 4522, we capture the turbulent nature of the stripping process. We measure the star formation rates using published Hα and measured 24 μm luminosities for all of our galaxies and find that some of them have suppressed star formation rates compared to similar mass counterparts in the field. We find a possible association between Hα and warm H₂ emission in three of the four galaxies observed. We conclude that the variation of H₂ properties observed in our sample is likely due to the galaxies being in different stages of ram-pressure stripping. Finally, we report on our efforts to improve the performance of the Lochkeed Arizona Infrared Spectrometer (LAIRS), a near-IR, tunable filter imager. We have made significant progress in identifying the sources of key issues such as the a highly asymmetric line profile and the unstable performance of the servo controller at the MMT. Solutions have been implemented for these issues, such as a revised mounting strategy for the tunable filter plates and a completely new controller with higher bandwidth. Significant progress has been made towards resolving these issues, but a few issues remain before LAIRS meets all of its requirements.
545

Reaktionskinetik von Verbrennungsprozessen in der Gasphase: Spektroskopische Untersuchungen der Geschwindigkeit, Reaktionsprodukte und Mechanismen von Elementarreaktionen und die Modellierung der Oxidation von Kohlenwasserstoffen mit detaillierten Reaktionsmechanismen / Reaction Kinetics of Combustion Processes in the Gas Phase: Spectroscopic Studies of Reaction Rates, Products and Mechansims of Elementary Reactions and the Modeling of the Oxidation of Hydrocarbons with Detailed Reaction Mechanisms

Zeuch, Thomas 04 July 2003 (has links)
No description available.
546

Mokyklos tvarkaraščių optimizavimas / School schedule optimizing

Pupeikienė, Lina 25 May 2004 (has links)
In this work was created algorithm of SA – Simulated Annealing method and GMJ – Global Minimizer for Java. GMJ it’s solution of so called frames of optimised tasks. The method of SA is a technique that has attracted significant attention as suitable for optimization problems of large scale. For practical purposes, simulated annealing has effectively “solved” the famous travelling salesman. At the heart of the method of simulated annealing is an analogy with thermodynamics, specifically with the way that liquids freeze and crystallize, or metals cool and anneal. So the essence of the process is slow cooling, allowing ample time for redistribution of the atoms as they lose mobility. This is the technical definition of annealing, and it is essential for ensuring that a low energy state will be achieved. GMJ – it’s a software solution of so called frames of global optimisation tasks. This method realizes: · algorithms of global optimisation (methods), · functions, that’s can be optimised (tasks), · objects, that’s can be showed on display (analysis). After the program was created, exhaustive inquiry of in this work realized methods was done: analysed influence of teachers, students and others different restrains multipliers to school scheduler making. The research was done using the data of college of Marijampolė. There was accomplished theoretical and experimental comparison of SA and the school schedule programs of others firms.
547

Aplinkos valdymo sistema neįgaliesiems / Environment Control System for the Disabled

Serafinavičius, Paulius 10 June 2004 (has links)
A design of a Smart Home system which is expected to help people with physical and speech impairments to control their living environment is given there. It was done during Eureka project E!2707 (PACS). Hardware and software analysis, algorithms and methods, usability test of developed system user interface are given there. A review of similar systems designed for disabled was done. Analysis of user requirements, detailed analysis and implementation ways of user interface are given there. The most popular building automation standards were analyzed and the most suitable one – Konnex association standard KNX was selected. Three different system block diagrams, software algorithm and its implementation methods were given and analyzed. A model of the user interface was created. An investigation was made. The goal of it is to evaluate the main user interface parameter – activation time which makes a better usability of the whole system.
548

Reperių sluoksniuočių tiesinių siečių tęsiniai / Extensions of linear connections of bundles of frames

Iliukevič, Viktorija 10 June 2004 (has links)
NB: santraukoje neįsikelia formulės! The graduation paper examines frame bundles B (Vn ), whose base is n–dimensional differential manifold Vn and the first differential extensions of this stratification J1B(Vn). The bundle of frames is normalized by way of linear connection object F ; provided this object is the linear function of coordinates p , then the linear connection of stratification B(Vn) defines affine connection Vn of reference space. The thesis analyses the overall linear connection and linear co-connection of stratification J1B(Vn) and related basal differentiations. It has been proven that the linear connection of bundle of frames B(Vn) indicates the linear connection and linear co-connection of extended stratification J1B(Vn), the relation between the ratios of the induced connection and the induced co-connection and the representation of the components of curvature objects of the obtained induced linear connection.
549

Asimptotiniai skleidiniai didžiųjų nuokrypių zonose / Asymptotic expansion in the large deviation zone

Deltuvienė, Dovilė 11 January 2005 (has links)
The novelty and originality of the work consists in the fact that in order to obtain asymptotic expansions with optimal values of the remainder terms in the zone of large deviations, along with the cumulant method the classical method of characteristic functions has to be used. In addition, when solving the problems stated in the work, other than the well known results in the problems of limit theorems of the probability theory and mathematical statistics, we have to estimate constants. Technically it is frequently rather a complicated task. The results obtained in the work have good opportunities to be applied in probability theory, mathematical statistics, econometric, etc. That is illustrated in the last section of the work in which theorems of large deviations are proved in the summation of weighted random variables with weights as well as discounted limit theorems.
550

Lietuvos vietos valdžios atstovų vertybinių orientacijų dinamika 1991-2001 / The dynamics of the value orientations of the lithuanian local government‘ representatives in 1991-2001

Mikėnienė, Svajonė 26 July 2005 (has links)
The research objective is to explore the dynamics of value orientations of the Lithuanian local government representatives in 1991-2001.

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