This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop better understanding of the spray breakup processes and provide better experimental inputs to improve the fidelity of numerical models. This work adresses two key research areas: determining the time required for a liquid column to break up in the crossflow (i.e., primary breakup time) and the effect of injector geometry on spray properties. A new diagnostic technique, the liquid jet light guiding technique that utilizes ability of the liquid jet to act as a waveguide for laser light was developed to determine the location where the liquid column breaks up, in order to obtain the primary breakup time. This study found that the liquid jet Reynolds number was an important factor that governed the primary breakup time and improved the existing correlation. Optical diagnostic techniques such as Phase Doppler Particle Analyzer, Liquid Jet Light Guiding Technique, Particle Image Velocimetry and Imaging techniques were employed to measure the spray properties that include spray penetration, droplet sizes and velocities, velocity field on the surface of the liquid jet and the location of the primary breakup time. These properties were measured for two injectors: one with a sharp transition and the other with a smooth transition. It was found that the spray created by the injector with a sharp transition forms large irregular structures while one with smooth transition produces a smooth liquid jet. The spray transition creates a spray that penetrates deeper into the crossflow, breakup up earlier and produces larger droplets. Additionally, this study reports the phenomenon of the liquid jet splitting into two or more jets in sprays created by the injector with a smooth transition.

Home healthcare has been a growing sector of the economy over the last three decades with roughly 23,000 companies now doing business in the U.S. producing over $56 billion in combined annual revenue. As a highly fragmented market, profitability of individual companies depends on effective management and efficient operations. This dissertation aims at reducing costs and improving productivity for home healthcare companies. The first part of the research involves the development of a new formulation for the therapist routing and scheduling problem as a mixed integer program. Given the time horizon, a set of therapists and a group of geographically dispersed patients, the objective of the model is to minimize the total cost of providing service by assigning patients to therapists while satisfying a host of constraints concerning time windows, labor regulations and contractual agreements. This problem is NP-hard and proved to be beyond the capability of commercial solvers like CPLEX. To obtain good solutions quickly, three approaches have been developed that include two heuristics and a decomposition algorithm. The first approach is a parallel GRASP that assigns patients to multiple routes in a series of rounds. During the first round, the procedure optimizes the patient distribution among the available therapists, thus trying to reach a local optimum with respect to the combined cost of the routes. Computational results show that the parallel GRASP can reduce costs by 14.54% on average for real datasets, and works efficiently on randomly generated datasets. The second approach is a sequential GRASP that constructs one route at a time. When building a route, the procedure tracks the amount of time used by the therapists each day, giving it tight control over the treatment time distribution within a route. Computational results show that the sequential GRASP provides a cost savings of 18.09% on average for the same real datasets, but gets much better solutions with significantly less CPU for the same randomly generated datasets. The third approach is a branch and price algorithm, which is designed to find exact optima within an acceptable amount of time. By decomposing the full problem by therapist, we obtain a series of constrained shortest path problems, which, by comparison are relatively easy to solve. Computational results show that, this approach is not efficient here because: 1) convergence of Dantzig-Wolfe decomposition is not fast enough; and 2) subproblem is strongly NP-hard and cannot be solved efficiently. The last part of this research studies a simpler case in which all patients have fixed appointment times. The model takes the form of a large-scale mixed-integer program, and has different computational complexity when different features are considered. With the piece-wise linear cost structure, the problem is strongly NP-hard and not solvable with CPLEX for instances of realistic size. Subsequently, a rolling horizon algorithm, two relaxed mixed-integer models and a branch-and-price algorithm were developed. Computational results show that, both the rolling horizon algorithm and two relaxed mixed-integer models can solve the problem efficiently; the branch-and-price algorithm, however, is not practical again because the convergence of Dantzig-Wolfe decomposition is slow even when stabilization techniques are applied. / text

Amongst the polar organic compounds occurring in unrefined and refined crude oils and the associated polluted production waters, complex mixtures of acids, known historically as naphthenic acids (NAs), have achieved prominence. This is particularly because NAs have been designated a toxicant class of concern in the oil sands process-affected water (OSPW) that has accumulated in vast quantities following exploitation of the oil sands of Northern Alberta, Canada in recent years. However, though there have been calls for NAs to be added to pollutant inventories, at the initiation of the current study, little knowledge existed of the exact composition of refined or unrefined NAs. The overall aim of the current study was therefore to identify individual NAs in refined (commercial) and unrefined (e.g. oil sands process-derived) complex mixtures of acids and then to assess the toxicity of any identified NAs. Individual NAs were tentatively identified by interpretation of the electron ionisation mass spectra of methyl ester derivatives, following comprehensive multidimensional gas chromatography-mass spectrometry (GCxGC-MS). Reference acids were then either purchased, or more commonly, where they were not commercially-available, synthesised, mainly by micro-hydrogenation methods, for co-chromatography and comparison of mass spectra of methyl esters with those of unknowns. The synthetic NAs, purified to >97% were then subjected to toxicological assessments using the Microtox™ assay. In all, 34 compounds were obtained pure enough for testing. Microtox results revealed that the toxicity endpoint (50% Inhibition Concentration, IC50) was between 0.004 and 0.7 mM. Exponential and other correlations were noted between carbon number and toxicity in several of the structural groups of acids assayed, which may be beneficial for predictions of toxicity of non-synthesised acids. Although n-hexanoic acid (IC50 0.7 mM) had the lowest toxicity, adamantane-type acids were the least toxic as a group overall. Conversely, the decahydronaphthalene (decalin)-type acids had the largest range of toxicities (IC50 0.004 to 0.3 mM) and the most toxic acid assayed was 3-decalin-1-yl-propanoic acid. According to USEPA guidelines many individual acids can be said to show low to medium toxicity. Since the acids in commercial and unrefined NAs occur in complex mixtures, an attempt was also made to assess mixture toxicity. Mixtures of individual structural groups of acids (e.g. acyclic isoprenoid acids, n-acids) and a mixture of all 34 acids were assessed. Apart from the adamantane sub-group of acids, all of the mixtures showed toxicities lower than the sum of the parts when calculated using equations for Concentration Addition and Model Deviation Ratios (simply the predicted IC50/Observed IC50). A hypothesis that achievement of a critical micelle concentration is required to produce toxicity was proposed to explain the lower than expected results. Some of the mass spectra of NA present in the commercial and unrefined mixtures were inconsistent with those of any of the alicyclic acids synthesised or purchased. These were hypothesised to be aromatic acids. Fractionation experiments of the NA mixtures using silver ion thin layer chromatography and solid phase extraction (Ag+TLC and Ag+SPE) were carried out in order to provide further evidence for aromatic acids. Ag+TLC allowed separation of a methylated NA mixture from OSPW into three distinct fractions; Ag+SPE resulted in eleven fractions, through the use of a wider range of solvents and differential solvent ratios. Analysis of the fractions by GC-MS revealed that each fraction was largely still made up of unresolved acids (as esters), although one or two fractions revealed some resolved acids. Use of averaged mass spectra and mass chromatography on each fraction revealed further resolved chromatographic peaks and associated interpretable mass spectra. Each of eight of the eleven sub-fractions were examined by GC-MS, in some cases by GCxGC-MS, and all by infrared spectroscopy, ultraviolet visible spectrophotometry and elemental analysis. A number of structures were proposed for the aromatic acids, including those with sulphur-containing moieties. It was noted that far from being minor components, aromatic acids comprised ca.25-40% of the OSPW acid extracts.

Crinoids are the most primitive living members of the Phylum Echinodermata. Though still present in reduced numbers today, crinoids were the dominant echinoderms from the Ordovician to the Permian. The crinoid body plan consists of three major regions, the column, the calyx, and the arms. Each region serves important functions in crinoids. The column raises the rest of the body into the water column for more efficient feeding. The calyx contains the visceral mass and mouth. Arms extend out from the top of the calyx to trap microorgansisms and suspended organic particles in the water column. A re-evaluation of these functional units is undertaken to understand the importance of various structures and to obtain discrete characters for use in a cladistic analysis. The relationship of crinoid crown groups has been an active area of research for the past couple of decades. With each proposed phylogenetic relationship, a new interpretation of thecal plate homology has been proposed. Here each study is re-examined in the light of new data. A review of functional morphology indicates a dual-reference system to be the most supported interpretation of plate homology. The two reference points in this system are the stem-cup and the cup-arm junctions, at the top and bottom of the calyx. The difference between a two-circlet and three-circlet crinoid is the presence or absence of the middle (basal) circlet. A new cladistic analysis is presented, with the topology of trees obtained giving support for the retention of Paleozoic crinoid stem and crown groups. Crinoids appear abruptly in the fossil record. Questions pertaining to origins and ancestral stock abound. A biogeography study is employed to look at the distribution of crinoids from the Early to Middle Ordovician. Locality information, combined with an understanding of the movement of major plates, paleoclimate data, an understanding of larval distribution, and a review of similar studies carried out on different taxa, gives insight into possible radiation and dispersal patterns of crinoids from the first half of the Ordovician. / text

Σκοπός της παρούσας Διπλωματικής Εργασίας είναι η μελέτη της εξέλιξης της νόσου της οστεοπόρωσης στη σπονδυλική στήλη με τη χρήση της μεθόδου των πεπερασμένων στοιχείων. Συγκεκριμένα, μοντελοποιείται η εφαρμογή θλιπτικού φορτίου στον δωδέκατο θωρακικό σπόνδυλο ασθενούς με οστεοπόρωση σε δύο διαδοχικές καταστάσεις – πριν και ένα χρόνο μετά την χορήγηση φαρμακευτικής αγωγής. Επιπλέον, κατά τη μελέτη, δοκιμάστηκαν διαφορετικές αποδόσεις μηχανικών ιδιοτήτων (μέτρο ελαστικότητας και βαθμός ανισοτροπίας) στο οστό, αρχικά στο μοντέλο ενός υγιούς σπονδύλου και στη συνέχεια στο εν λόγω μοντέλο του οστεοπορωτικού. Όλα τα μοντέλα κατασκευάστηκαν με την ίδια μεθοδολογία. Η σύγκριση τόσο των δύο καταστάσεων της νόσου, όσο και των διαφορετικών αποδόσεων των μηχανικών ιδιοτήτων, γίνεται βάσει των ισοδύναμων Τάσεων και Παραμορφώσεων κατά von Mises και των Μετατοπίσεων κατά τον οβελιαίο άξονα z. Οι υπό εξέταση μέγιστες τιμές των προαναφερθέντων μεγεθών που προκύπτουν από την ανάλυση πεπερασμένων στοιχείων, παρουσιάζουν μείωση στη δεύτερη κατάσταση. Επιπλέον, τα αποτελέσματα της διαφορετικής απόδοσης μηχανικών ιδιοτήτων, μαρτυρούν ότι ο βαθμός ανισοτροπίας και ο τρόπος συσχέτισης του μέτρου ελαστικότητας με την οστική πυκνότητα, επηρεάζουν το αποτέλεσμα της μηχανικής ανάλυσης. Παρόλα αυτά, η συγκριτική αξιολόγηση των δύο διαδοχικών καταστάσεων του σπονδύλου δεν φαίνεται να επηρεάζεται από τον τρόπο ορισμού των μηχανικών ιδιοτήτων. Γενικά, η αλλαγή που παρατηρείται στις αξονικές τομογραφίες της δεύτερης κατάστασης σε σχέση με την πρώτη σε συνδυασμό με τη μεταβολή των υπό εξέταση μεγεθών, ιδιαίτερα της ισοδύναμης Παραμόρφωσης κατά von Mises, οδηγούν στο συμπέρασμα ότι στη δεύτερη κατάσταση ο υπό εξέταση σπόνδυλος καταπονείται λιγότερο που σημαίνει ότι η ακολουθούμενη φαρμακευτική αγωγή έχει θετικά αποτελέσματα. / The purpose of this master thesis is to perform a computational (finite element, FEM) study on the progress of the spinal osteoporosis, between two sequential examinations consisting of CT scanning. For this purpose, two finite element models of the twelfth thoracic vertebra of a patient with osteoporosis were created, one for every examination – before and one year after the prescription of medication – and compression loading was simulated. Moreover, a material sensitivity study has taken place, first on a FE model of a healthy vertebra and then on the two models of the osteoporotic one. All FE models were created with the same methodology. For the comparison of the two sequential examinations, as well as of the different material assignment, three mechanical quantities were used: equivalent von Mises Stress, equivalent von Mises Strain and Displacement on the sagittal axis (z). From the output of FE analysis, it seems that the maximum values of the beforementioned quantities decrease in the second model of the osteoporotic vertebra. Also, it becomes clear that the degree of anisotropy and the correlation of bone mineral density vs. Young’s modulus, significantly affect the output of FE analysis. However, the comparison of the two osteoporotic models is not affected by the material assignment. As a conclusion, there is a remarkable change in the CT scans of the second examination combined with a reduction of the strains in the vertebra - coming as a result of the FE analysis - that shows the positive influence of the prescribed medication.

In this thesis, it is shown how aflatoxins can be determined in biological material. The thesis is a summary of five papers. Aflatoxins are carcinogenic mycotoxins produced by Aspergillus moulds. Methods were developed for the determination of aflatoxins in samples of airborne dust and human urine collected at feed factories. For the dust samples from such agricultural products as copra, cotton seed and maize, methods were developed for the determination of aflatoxins B1, B2, G1 and G2. For urine samples, methods were developed for analysing the four aflatoxins above that naturally occur in dust, and the metabolites aflatoxins M1 and Q1. Sample preparation of dust samples included solvent extraction, filtration and immunoaffinity column extraction. Urine samples were cleaned up using immunoaffinity column extraction or solid-phase extraction using ethyl bonded-phase columns. All extractions with these columns were automated by means of a laboratory robot. Reversed-phase liquid chromatography was used to separate the aflatoxins in the cleaned-up extracts. Detection was performed by fluorescence after post-column derivatization by addition of bromine. Parameters for the derivatization were studied using factorial designs. To confirm the identity of aflatoxins in naturally contaminated airborne dust samples and spiked urine, liquid chromatography was combined with electrospray mass spectrometry. The detection limits of the aflatoxins in dust samples were in the range 1.8-3.1 ng/g in 10-mg dust samples using fluorescence detection. Aflatoxins were determined in spiked urine down to the 6.8-18 pg/ml level. In naturally contaminated dust of copra and cotton seed, aflatoxins were detected with a content of 9-50 pg/mg of aflatoxin Bi. No aflatoxins could be detected in any urine sample obtained from feed factory workers that were less than 6.8 pg/ml of aflatoxins B1, B2, G1 and G2 and less than 18 pg/ml of aflatoxins M1 and Q1. / <p>Diss. (sammanfattning) Umeå : Univ., härtill 5 uppsatser</p> / digitalisering@umu

No description available.

Tyrimo objektas ir metodai: šermukšnių (Sorbus L.) rūšių ir veislių lapų fenolinių junginių kiekybinės sudėties ir antioksidantinio aktyvumo tyrimas. Antioksidantinis aktyvumas nustatytas ABTS ir FRAP spektrofotometriniais bei efektyviosios skysčių chromatografijos pokolonėliniais metodais (ESC-ABTS ir ESC-FRAP). Darbo tikslas: ištirti šermukšnio (Sorbus L.) genties augalų lapų bendrą fenolinių junginių kiekį ir jo įvairavimą atskirose rūšyse ir veislėse bei įvertinti ekstraktų antioksidantinį aktyvumą spektrofotometriniais ir ESC pokolonėliniais metodais. Darbo uždaviniai: Nustatyti bendrą fenolinių junginių kiekį šermukšnių augalinėse žaliavose Folin-Ciocalteau metodu. Atlikti šermukšnio genties rūšių lapų kokybinę ir kiekybinę fenolinių junginių analizę ESC metodu. Įvertinti ekstraktų antiradikalinį aktyvumą ABTS spektrofotometriniu metodu. Atlikti ekstraktų redukcinių savybių tyrimą FRAP spektrofotometriniu metodu. Įvertinti atskirų junginių indėlį į bendrą ekstrakto antioksidantinį aktyvumą ESC-ABTS ir ESC-FRAP pokolonėliniais metodais. Įvertinti koreliacinį ryšį tarp bendro fenolinių junginių kiekio ir ekstraktų antioksidantinio aktyvumo. Išvados: Spektrofotometrinės analizės metu didžiausi fenolinių junginių kiekiai nustatyti S. caucasica Zinserl. rūšies (82,52±0,94 mg/g) ir ‘Alaya krupnaya’ veislės (131,76±7,04 mg/g) lapų pavyzdžiuose. Didžiausias redukcinis aktyvumas FRAP metodu (TE, µmol/g) nustatytas S. caucasica Zinserl. rūšies ir ‘Alaya krupnaya’ veislės... [toliau žr. visą tekstą] / Object and methods: quantitative analysis of phenolic compounds in rowan (Sorbus L.) species and hybrids and evaluation of antioxidant activity. Antioxidant activity was assessed by ABTS and FRAP spectrophotometric methods and by high performance liquid chromatography post-column reaction. Aim: to investigate quantitative composition of phenolic compounds and its variance in different rowan (Sorbus L.) species and hybrids and assess antioxidant activity of extracts by spectrophotometric and chromatographic methods. Objective: Evaluate quantitative composition of phenolic compounds in Sorbus L. species and hybrids leaves by Folin-Ciocalteau assay. Evaluate qualitative and quantitative composition of phenolic compounds in rowan species by high performance liquid chromatography. Assess free radical scavenging activity and determine reduction power of rowan leaves extracts by ABTS and FRAP spectrophotometric assay. Estimate correlation between quantity of phenolics and antioxidant activity in Sorbus L. leaves extracts. Assess input of individual compounds in overall antioxidant activity of extracts evaluated by HPLC-ABTS and HPLC-FRAP post-column methods. Results: In spectrophotometric analysis, the highest amount of phenolic compounds were determined in S.caucasica Zinserl. (82,52±0,94 mg/g) and ‘Alaya krupnaya’ (131,76±7,04 mg/g) leaves extracts. The highest antioxidant activity (TE, µmol/g) was observed in S.caucasica Zinserl. and ‘Alaya krupnaya’ ethanolic extracts using FRAP... [to full text]

Establishment of relationships for predicting the lateral drift demands of near-fault ground motions is one of the major challenges in earthquake engineering. Excessive lateral drifts caused by earthquake ground motions are the major causes of structural damage observed in structures. In this study, some of the fundamental characteristics of near-fault ground motions are examined. Response characteristics of elastic frame structures to near-fault ground motions are investigated. An approximate method for estimating the elastic ground story and interstory drifts for regular frame type structures is presented. Inelastic displacement demands imposed on elasto-plastic single degree of freedom (SDOF) systems subjected to near-fault ground are examined. Three equations for estimating the maximum lateral inelastic displacement demand from the maximum elastic displacement demand are established. Two of these equations relate the inelastic and elastic displacement demands through natural period and strength reduction factor. The third equation relates the inelastic and elastic displacement demands through the ratio of natural period to pulse period and the strength reduction factor. Efficiency of the natural period to pulse period ratio for estimating the inelastic displacement ratio is shown. Error statistics of the proposed equations are presented and compared with similar studies in the literature. According to the results, these equations can be used for quick and rough estimates of displacement demands imposed on regular elastic moment resisting frames and elasto-plastic single degree of systems.

Despite the developments in the last decades, field performance information for short aggregate pier improved ground is needed for future design and to develop a better understanding of the performance of the short (floating) aggregate piers. A full-scale field study was performed to investigate the floating aggregate pier behavior in a soft clayey soil. Site investigations included five boreholes and sampling, four CPT soundings, and SPT and laboratory testing. The soil profile consisted of 8m thick compressible clay overlying weathered rock. Four large plate load test stations were prepared. A rigid steel footing having plan dimensions of 3.0m by 3.5m were used for loading. Four 65cm diameter reaction piles and steel cross beams were used to load the soil in each station. First test comprised of loading the untreated soil up to 250 kPa with increments, and monitoring the surface settlements. Moreover, distribution of settlements with depth is recorded by means of deep settlement gages installed prior to loading. Other three tests were conducted on clay soil improved by rammed aggregate piers. In each station, seven stone columns were installed, having a diameter of 65cm, area ratio of 0.25, placed in a triangular pattern with a center to center spacing of 1.25m. The length of the columns were 3m, 5m in the two station resembling floating columns, and 8m in the last station to simulate end bearing columns to observe the level of the improvement in the floating columns. Field instrumentations included surface and deep settlement gages, and load cell placed on a aggregate pier to determine distribution of the applied vertical stress between the column and the natural soil , thus to find magnitude of the stress concentration factor, n , in end bearing and floating aggregate piers. It has been found that, the presence of floating aggregate piers reduce settlements, revealing that major improvement in the settlements takes place at relatively short column lengths. It has been also found that the stress concentration factor is not constant, but varies depending on the magnitude of the applied stress. The magnitude of stress concentration factor varies over a range from 2.1 to 5.6 showing a decreasing trend with increasing vertical stress.