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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.
101

Use of Simulation Optimization for Clearance of Flight Control Laws

Fredman, Kristin, Freiholtz, Anna January 2006 (has links)
<p>Before a new flight control system is released for flight, a huge number of simulations are evaluated to find weaknesses of the system. This process is called flight clearance. Flight clearance is a very important but time consuming process. There is a need of better flight clearance methods and one of the most promising methods is the use of optimization. In this thesis the flight clearance of a simulation model of JAS 39 Gripen is examined. Two flight clearance algorithms using two different optimization methods are evaluated and compared to each other and to a traditional flight clearance method.</p><p>In this thesis the flight clearance process is separated into three cases: search for the worst flight condition, search for the worst manoeuvre and search for the worst flight condition including parameter uncertainties. For all cases the optimization algorithms find a more dangerous case than the traditional method. In the search for worst flight condition, both with and without uncertainties, the optimization algorithms are to prefer to the traditional method with respect to the clearance results and the number of objective function calls. The search for the worst manoeuvre is a much more complex problem. Even as the algorithms find more dangerous manoeuvres than the traditional method, it is not certain that they find the worst manoeuvres. If not other methods should be used the problem has to be rephrased. For example other optimization variables or a few linearizations of the optimization problem could reduce the complexity.</p><p>The overall impression is that the need of information and problem characteristics define which method that is most suitable to use. The information required must be weighed against the cost of objective function calls. Compared to the traditional method, the optimization methods used in this thesis give extended information about the problems examined and are better to locate the worst case.</p>
102

Diskussion om röjningsrösen : med teorier om gravrösen i fossil åkermark och skärvstenshögar

Emilsson, Andreas January 2009 (has links)
<p>This paper aims to investigate the connection between clearance cairns and burial cairns. From this point of view I try to answer the questions why they are built in the same area and why these two different types of cairns are so similary constructed. Further I consider different theories about mounds of fire-cracked stones.</p>
103

Intraperitoneal 5-Fluorouracil treatment of cancer - clinical and experimental studies

Öman, Mikael January 2004 (has links)
<p>Background:Pancreas cancer is a most aggressive malignancy. More than 80% of patients diagnosed with pancreas cancer, exhibit such advanced disease, that curative surgery is impossible. Systemic chemotherapy prolongs survival to 5-9 months. High concentrations of chemotherapeutic agents in the abdominal cavity and in the lymphatics draining the area is achieved by intraperitoneal administration. Vasopressin decreases splanchnic blood flow, reducing the intraperitoneal uptake of drugs, thus raising the local and lymphatic dose intensity.</p><p>Aim: The aim of the study was to investigate the feasibility and tumour response of intraperitoneal 5-Fluorouracil (5-FU) treatment in non-resectable pancreas cancer, using vasopressin to improve the pharmacokinetic profile. Further, to study the effect of vasopressin on peritoneal blood flow, altered by intraperitoneal 5-FU or the presence of peritoneal carcinomatosis.</p><p>Methods: In the animal experiments, the 133Xe-clearance technique and as a comparison Laser doppler flow, were used to identify changes of peritoneal blood flow caused by vasopressin in unmanipulated animals and in animals with peritoneal carcinomatosis or animals given intraperitoneal 5-FU. In the clinical studies, 68 (39 women/29 men) patients, with a non-resectable ductal pancreas cancer and a Karnovsky Index ≥70 were included. Patients were treated with 750-1500 mg/m2 5-FU intraperitoneally through a Port-a-cath and Leucovorin 100 mg/m2 intravenously on two consecutive days every 21 days until progression. Seventeen patients, receiving 750 mg/m2 5-FU, were given concomitant vasopressin 0.1 IU/min during 180 minutes, alternatively day 1 or 2.</p><p>Results: In the animal experiments, vasopressin 0.07 IU/kg/min significantly reduced the 133Xe-clearance. Intraperitoneal 5-FU decreased the basal peritoneal blood flow and abrogated the vasopressin effect for 1-2 days. The presence of peritoneal carcinomatosis did not influence the basal peritoneal blood flow, nor the reduction of peritoneal blood flow caused by vasopressin. In the clinical studies, the treatment with intraperitoneal 5-FU was well tolerated, with no WHO Grade 3 or 4 toxicity with doses up to 1250 mg/m2. Thirty patients achieved at least stable disease at three months. The median survival time was 8.0 (range 0.8-54.1) months. There was a significant reduction of 5-FU Cmax on day 2, but no significant reduction of AUC, when vasopressin was given.</p><p>Conclusion: Peritoneal blood flow changes caused by vasopressin can be estimated with the 133Xe-clearance technique. Intraperitoneal 5-FU but not peritoneal carcinomatosis decreases the vasopressin induced 133Xe-clearance reduction, 1-2 days after administration. In patients with non-resectable pancreas cancer, intraperitoneal 5-FU up to 1250 mg/m2 for two days every third week can be given without WHO grade 3 and 4 toxicity. The treatment is well tolerated with few and minor side effects. Tumour responses were observed. Addition of vasopressin does not significantly enhance the pharmacokinetics of intraperitoneal 5-Flurorouracil, but adds toxicity.</p>
104

Magnetically targeted deposition and retention of particles in the airways for drug delivery

Ally, Javed Maqsud 06 1900 (has links)
This thesis examines the mechanisms of magnetic particle deposition and retention in human airways for magnetically targeted drug delivery. As this is a novel application, fundamental studies were performed to establish the necessary background knowledge for further development. Magnetic particle deposition from an aerosol in simulated airway conditions was studied using numerical and experimental models. The model results showed qualitative agreement; discrepancies were due to particle aggregation, which enhances deposition. Aerosol flow rate had a limited effect; the main factor in effective deposition was the proximity of the particle trajectories to the magnets. This spatial bias shows the importance of particle distribution in the flow as well as magnetic field geometry. These studies demonstrated the feasibility of capturing magnet particles from aerosol in airway conditions. For retention, clearance of particles due to motion of the mucus lining of the airways must be overcome. Particle retention was studied in vitro using various liquids to simulate mucus and identify relevant parameters. An ex vivo animal tissue model was used to demonstrate feasibility. Retention of 3-5 m diameter iron particles was achieved at reduced liquid/mucus viscosities. Larger (~100 m) particles were retained at normal mucus viscosities. The size dependence shows that particle aggregation after deposition is crucial for effective retention. In vitro retention experiments showed aggregate size is correlated with liquid viscosity, i.e. formation of aggregates is limited by forces opposing particle motion along the mucus layer interface. To determine these forces, particle motion on various air-liquid interfaces, chosen to simulate different mucus properties in isolation, was studied. When surfactants are present, as in the mucus layer, particle motion is limited by a velocity-dependent surface tension gradient as well as viscous drag. Pulling particles through the mucus layer into the tissue beneath was also considered as a potential retention strategy. The force required to pull particles through the mucus layer was also studied using various liquids to simulate mucus properties. In addition to the surface tension force holding the particles at the interface, hydrodynamic forces must be overcome to pull particles into or out of a liquid film such as the mucus layer.
105

Hur utvecklas den svenska minröjningsfunktionen inom marinen?

Arby, Nathaniel January 2009 (has links)
<p>Sjöminan har sänkt och skadat mer tonnage än alla andra vapensystem till sjöss. Då medel föder motmedel har sjöminan och minröjningen följt varandra i en lång duell.</p><p>Huvudsyftet med denna uppsats är att undersöka hur de svenska minröjningsförbanden utvecklas inom taktik och teknik och hur dessa komponenter förhåller sig till varandra. Uppsatsen söker även svaret på hur utvecklingen från minröjningsklass Landsort till minröjningsklass Koster skett.</p><p>Med hjälp av deskriptiv metod kommer <em>Militärstrategisk doktrin, Doktrin för marina operationer</em> samt <em>Försvarsmaktens läroböcker i Mineringstjänst</em>, <em>Minmotmedelstjänst</em> och <em>Minröjningstjänst</em> att användas för att redogöra hur den marina taktiken och tekniken utvecklas som ett medel i duellen mot sjöminan.</p><p>De svenska minröjningsfartygens taktiska och tekniska utveckling grundar sig på de militära basfunktionerna, <em>ledning, verkan, skydd, rörelse, underrättelse samt uthållighet</em>. Samtidigt utvecklas minröjningsförbanden i Försvarsmakten mot ett, både för personal och materiel, säkrare och effektivare förband.</p> / <p>The main purpose with this essay is to examine the development of the Swedish mine warfare branch both tactical and technical and how these two components are combined to maximize the effect. The essay also analyses the midlife upgrade of the MCMV Landsort class towards the MCMV Koster class.</p><p>This essay will describe on the basis of the Swedish doctrines and mine warfare textbooks how the naval tactics and technology function as a foundation for development of new means in the duel against the sea mine.</p><p>The sea mine is a weapon system that has been used during several centuries and has sunk more tonnage than all other weapon systems together. As long as there have been sea mines, there has also existed its counterpart, the mine counter measures.</p><p>The Swedish MCMV’s technological and tactical developments strive towards fulfilling the six mandatory functions in warfare, <em>command, effect, protection, mobility, intelligence and endurance</em>. The modern MCMV develops toward a more secure and efficient unit.</p>
106

Intraperitoneal 5-Fluorouracil treatment of cancer - clinical and experimental studies

Öman, Mikael January 2004 (has links)
Background:Pancreas cancer is a most aggressive malignancy. More than 80% of patients diagnosed with pancreas cancer, exhibit such advanced disease, that curative surgery is impossible. Systemic chemotherapy prolongs survival to 5-9 months. High concentrations of chemotherapeutic agents in the abdominal cavity and in the lymphatics draining the area is achieved by intraperitoneal administration. Vasopressin decreases splanchnic blood flow, reducing the intraperitoneal uptake of drugs, thus raising the local and lymphatic dose intensity. Aim: The aim of the study was to investigate the feasibility and tumour response of intraperitoneal 5-Fluorouracil (5-FU) treatment in non-resectable pancreas cancer, using vasopressin to improve the pharmacokinetic profile. Further, to study the effect of vasopressin on peritoneal blood flow, altered by intraperitoneal 5-FU or the presence of peritoneal carcinomatosis. Methods: In the animal experiments, the 133Xe-clearance technique and as a comparison Laser doppler flow, were used to identify changes of peritoneal blood flow caused by vasopressin in unmanipulated animals and in animals with peritoneal carcinomatosis or animals given intraperitoneal 5-FU. In the clinical studies, 68 (39 women/29 men) patients, with a non-resectable ductal pancreas cancer and a Karnovsky Index ≥70 were included. Patients were treated with 750-1500 mg/m2 5-FU intraperitoneally through a Port-a-cath and Leucovorin 100 mg/m2 intravenously on two consecutive days every 21 days until progression. Seventeen patients, receiving 750 mg/m2 5-FU, were given concomitant vasopressin 0.1 IU/min during 180 minutes, alternatively day 1 or 2. Results: In the animal experiments, vasopressin 0.07 IU/kg/min significantly reduced the 133Xe-clearance. Intraperitoneal 5-FU decreased the basal peritoneal blood flow and abrogated the vasopressin effect for 1-2 days. The presence of peritoneal carcinomatosis did not influence the basal peritoneal blood flow, nor the reduction of peritoneal blood flow caused by vasopressin. In the clinical studies, the treatment with intraperitoneal 5-FU was well tolerated, with no WHO Grade 3 or 4 toxicity with doses up to 1250 mg/m2. Thirty patients achieved at least stable disease at three months. The median survival time was 8.0 (range 0.8-54.1) months. There was a significant reduction of 5-FU Cmax on day 2, but no significant reduction of AUC, when vasopressin was given. Conclusion: Peritoneal blood flow changes caused by vasopressin can be estimated with the 133Xe-clearance technique. Intraperitoneal 5-FU but not peritoneal carcinomatosis decreases the vasopressin induced 133Xe-clearance reduction, 1-2 days after administration. In patients with non-resectable pancreas cancer, intraperitoneal 5-FU up to 1250 mg/m2 for two days every third week can be given without WHO grade 3 and 4 toxicity. The treatment is well tolerated with few and minor side effects. Tumour responses were observed. Addition of vasopressin does not significantly enhance the pharmacokinetics of intraperitoneal 5-Flurorouracil, but adds toxicity.
107

Hur utvecklas den svenska minröjningsfunktionen inom marinen?

Arby, Nathaniel January 2009 (has links)
Sjöminan har sänkt och skadat mer tonnage än alla andra vapensystem till sjöss. Då medel föder motmedel har sjöminan och minröjningen följt varandra i en lång duell. Huvudsyftet med denna uppsats är att undersöka hur de svenska minröjningsförbanden utvecklas inom taktik och teknik och hur dessa komponenter förhåller sig till varandra. Uppsatsen söker även svaret på hur utvecklingen från minröjningsklass Landsort till minröjningsklass Koster skett. Med hjälp av deskriptiv metod kommer Militärstrategisk doktrin, Doktrin för marina operationer samt Försvarsmaktens läroböcker i Mineringstjänst, Minmotmedelstjänst och Minröjningstjänst att användas för att redogöra hur den marina taktiken och tekniken utvecklas som ett medel i duellen mot sjöminan. De svenska minröjningsfartygens taktiska och tekniska utveckling grundar sig på de militära basfunktionerna, ledning, verkan, skydd, rörelse, underrättelse samt uthållighet. Samtidigt utvecklas minröjningsförbanden i Försvarsmakten mot ett, både för personal och materiel, säkrare och effektivare förband. / The main purpose with this essay is to examine the development of the Swedish mine warfare branch both tactical and technical and how these two components are combined to maximize the effect. The essay also analyses the midlife upgrade of the MCMV Landsort class towards the MCMV Koster class. This essay will describe on the basis of the Swedish doctrines and mine warfare textbooks how the naval tactics and technology function as a foundation for development of new means in the duel against the sea mine. The sea mine is a weapon system that has been used during several centuries and has sunk more tonnage than all other weapon systems together. As long as there have been sea mines, there has also existed its counterpart, the mine counter measures. The Swedish MCMV’s technological and tactical developments strive towards fulfilling the six mandatory functions in warfare, command, effect, protection, mobility, intelligence and endurance. The modern MCMV develops toward a more secure and efficient unit.
108

Oral nutrition or water loading before hip replacement surgery; a randomized clinical trial

Ljunggren, Stefan, Hahn, Robert G January 2012 (has links)
Background Surgery induces insulin resistance that might be alleviated by a nutritional drink given preoperatively. The authors hypothesized that some of the beneficial effects of the drink could be attributed to the volume component (approximately 1 L) rather than to the nutrients. Methods Sixty patients scheduled for elective total hip replacement under spinal anesthesia were recruited to a clinical trial, and randomly allocated to preoperative fasting, to oral ingestion of tap water, or to oral ingestion of a carbohydrate drink. An intravenous glucose tolerance test calculated glucose clearance and insulin sensitivity on the day before surgery, in the postoperative ward, and on the day after surgery. Other parameters were stress (cortisol in plasma and urine), muscle catabolism (urinary 3-methylhistidine), and wellbeing. Results Fifty-seven patients completed the study. In the postoperative ward, the glucose clearance and the insulin response had decreased from the previous day by 23% and 36%, respectively. Insulin sensitivity did not decrease until the next morning (−48%) and was due to an increased insulin response (+51%). Cortisol excretion was highest on the day of surgery, while 3-methylhistidine increased 1 day later. Follow-up on the third postoperative day showed an average of 1.5 complications per patient. Wellbeing was better 2 weeks after than before the surgery. None of the measured parameters differed significantly between the study groups. Conclusions Preoperative ingestion of tap water or a nutritional drink had no statistically significant effect on glucose clearance, insulin sensitivity, postoperative complications, or wellbeing in patients undergoing elective hip surgery. / <p>Funding Agencies|Olle Engkvist Byggmastare Foundation||Stockholm County Council|2009-0433|</p>
109

Analysis and modeling of underfill flow driven by capillary action in flip-chip packaging

Wan, Jianwu 28 January 2005
Flip-chip underfilling is a technology by which silica-filled epoxy resin is used to fill the micro-cavity between a silicon chip and a substrate, by dispensing the liquid encapsulant at elevated temperatures along the periphery of one or two sides of the chip and then allowing capillary action to draw the material into the gap. Since the chip, underfill material, and substrate solidify together as one unit, thermal stresses on solder joints during the temperature cycling (which are caused by a mismatch in the coefficients of thermal expansion between the silicon chip and the organic substrate) can be redistributed and transferred away from the fragile bump zone to a more strain-tolerant region. Modeling of the flow behaviour of a fluid in the underfill process is the key to this technology. One of the most important drawbacks in the existing models is inadequate treatment of non-Newtonian fluids in the underfill process in the development of both analytical models and numerical models. Another important drawback is the neglect of the presence of solder bumps in the existing analytical models. This thesis describes a study in which a proper viscosity constitutive equation, power-law model, is employed for describing the non-Newtonian fluid behaviour in flip-chip package. Based on this constitutive equation, two analytical models with closed-form solutions for predicting the fluid filling time and fluid flow front position with respect to time were derived. One model is for a setting with two parallel plates as an approximate to flip-chip package, while the other model is for a setting with two parallel plates within which an array of solder bumps are present. Furthermore, a numerical model using a general-purpose finite element package ANSYS was developed to predict the fluid flow map in two dimensions. The superiority of these models to the existing models (primarily those developed at Cornell University in 1997) is confirmed based on the results of the experiments conducted in this study. This thesis also presents a finding of the notion of critical clearance in the design of a flip-chip package through a careful simulation study using the models developed. The flip-chip package design should make the clearance between solder bumps larger than the critical clearance.
110

Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease

Brown, Meghan 05 December 2011 (has links)
Rationale: Ventilation inhomogeneity (VI) may be an early sign of obstructive airway disease. The lung clearance index (LCI) has been suggested as a sensitive marker of VI, although it has not been well characterized in young children in health and in those with CF and asthma. Objective: To determine if LCI can detect VI in asymptomatic infants and preschool-age subjects with CF or wheeze/asthma compared to healthy controls. Methods: Sulphur hexafluoride (SF6) multiple breath washout (MBW) testing was completed in all subjects. Results: LCI was found to be dependent on age in a large healthy cohort. Accounting for age, LCI was significantly elevated in disease groups compared to healthy controls in early childhood, illustrating early presence of VI in wheezy infants and the progression of disease in CF. Furthermore, the effects of breathing pattern and the variability of MBW parameters showed positive associations with age and VI.

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