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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.
1

Kompiuterizuoto inhibicinio kontrolės ir laboratorinių testų vertė nustatant minimalią hepatinę encefalopatiją / Value of computerized inhibitory control test and blood tests in minimal hepatic encephalopathy diagnosis

Savlan, Ilona 03 March 2014 (has links)
Darbo tikslas – nustatyti kompiuterizuoto inhibicinio kontrolės testo (IKT), IL-6, amoniako bei įprastinių kraujo rodiklių vertę diagnozuojant kognityvinius sutrikimus sergantiems lėtinėmis kepenų ligomis. Darbo uždaviniai: nustatyti kognityvinių sutrikimų dažnį, galimus rizikos veiksnius, palyginti IKT ir kraujo testų rezultatus lėtinio hepatito ir kepenų cirozės grupėse; nustatyti IKT bei IL-6, įprastinių kraujo testų vertę minimaliai hepatinei encefalopatijai (MHE). Iki šiol netirta ar pacientai, sergantys lėtiniu hepatitu ir kognityviniais sutrikimais, neturi analogiškų IKT rodiklių pakitimų, IL-6 koncentracijos padidėjimo kaip sergantieji kepenų ciroze ir MHE. Netirta kokie kraujo ar IKT rodikliai kognityvinius sutrikimus prognozuoja geriausia. Į tyrimą įtraukti 62 sergantieji kepenų ciroze be hepatinės encefalopatijos, 73 lėtiniu hepatitu bei 53 sveiki asmenys. Tą pačią dieną buvo atliekami kraujo tyrimai, psichometriniai testai ir IKT. Lėtinio hepatito grupėje kognityviniai sutrikimai nustatyti 54,8 %, о kepenų cirozės grupėje MHE ¬ 71,0 % tiriamųjų asmenų. Kognityvinius sutrikimus predisponuoja trumpesnė mokymosi trukmė, fibrozės laipsnis, dvigubas etiologinis veiksnys, amžius ir lytis įtakos neturi. Lėtinio hepatito grupėje kognityviniai sutrikimai koreliuoja su IKT rodikliais ir kepenų fermentų koncentracijos padidėjimu, o kepenų cirozių grupėje su IKT rodikliais ir IL-6 koncentracija kraujyje. Išvados: Kognityvinius sutrikimus sergant lėtiniu hepatitu ar... [toliau žr. visą tekstą] / The aim of the study was to ascertain a value of computerized inhibitory control test (ICT), routine blood tests, peripheral blood ammonia and IL-6 concentration for diagnosis of cognitive disorders in patients with chronic liver diseases. Tasks: to assess a frequency of cognitive impairments and associated risk factors and to compare ICT and blood tests results in chronic hepatitis and cirrhotic patients; to ascertain ICT, IL-6 and routine blood tests values for diagnosis of minimal hepatic encephalopathy (MHE). Until now there were no studies performed whether chronic hepatitis patients with cognitive disorders have analogous ICT, IL-6 and other tests abnormalities as cirrhotic patients with MHE. It has not been studied which ICT and other tests results predict best the cognitive disorders in such patients. 62 cirrhotic patients without overt hepatic encephalopathy, 73 chronic hepatitis and 53 healthy individuals were enrolled. On the same day blood tests, psychometric and ICT tests were performed by every participant. Cognitive disorders were detected in 54,8% of chronic hepatitis patients. In cirrhotic patients MHE was found in 71,0%. Cognitive disorders predispose shorter study time, the fibrosis score, double etiologic factor, while age and gender has no influence. In chronic hepatitis patients the cognitive impairments correlate with ICT and elevated liver enzymes. In cirrhotic patients cognitive disorders correlate with ICT and IL-6 concentration. Conclusion: the... [to full text]
2

Value of computerized inhibitory control test and blood tests in minimal hepatic encephalopathy diagnosis / Kompiuterizuoto inhibicinio kontrolės ir laboratorinių testų vertė nustatant minimalią hepatinę encefalopatiją

Savlan, Ilona 03 March 2014 (has links)
The aim of the study was to ascertain a value of computerized inhibitory control test (ICT), routine blood tests, peripheral blood ammonia and IL-6 concentration for diagnosis of cognitive disorders in patients with chronic liver diseases. Tasks: to assess a frequency of cognitive impairments and associated risk factors and to compare ICT and blood tests results in chronic hepatitis and cirrhotic patients; to ascertain ICT, IL-6 and routine blood tests values for diagnosis of minimal hepatic encephalopathy (MHE). Until now there were no studies performed whether chronic hepatitis patients with cognitive disorders have analogous ICT, IL-6 and other tests abnormalities as cirrhotic patients with MHE. It has not been studied which ICT and other tests results predict best the cognitive disorders in such patients. 62 cirrhotic patients without overt hepatic encephalopathy, 73 chronic hepatitis and 53 healthy individuals were enrolled. On the same day blood tests, psychometric and ICT tests were performed by every participant. Cognitive disorders were detected in 54,8% of chronic hepatitis patients. In cirrhotic patients MHE was found in 71,0%. Cognitive disorders predispose shorter study time, the fibrosis score, double etiologic factor, while age and gender has no influence. In chronic hepatitis patients the cognitive impairments correlate with ICT and elevated liver enzymes. In cirrhotic patients cognitive disorders correlate with ICT and IL-6 concentration. Conclusion: the... [to full text] / Darbo tikslas – nustatyti kompiuterizuoto inhibicinio kontrolės testo (IKT), IL-6, amoniako bei įprastinių kraujo rodiklių vertę diagnozuojant kognityvinius sutrikimus sergantiems lėtinėmis kepenų ligomis. Darbo uždaviniai: nustatyti kognityvinių sutrikimų dažnį, galimus rizikos veiksnius, palyginti IKT ir kraujo testų rezultatus lėtinio hepatito ir kepenų cirozės grupėse; nustatyti IKT bei IL-6, įprastinių kraujo testų vertę minimaliai hepatinei encefalopatijai (MHE). Iki šiol netirta ar pacientai, sergantys lėtiniu hepatitu ir kognityviniais sutrikimais, neturi analogiškų IKT rodiklių pakitimų, IL-6 koncentracijos padidėjimo kaip sergantieji kepenų ciroze ir MHE. Netirta kokie kraujo ar IKT rodikliai kognityvinius sutrikimus prognozuoja geriausia. Į tyrimą įtraukti 62 sergantieji kepenų ciroze be hepatinės encefalopatijos, 73 lėtiniu hepatitu bei 53 sveiki asmenys. Tą pačią dieną buvo atliekami kraujo tyrimai, psichometriniai testai ir IKT. Lėtinio hepatito grupėje kognityviniai sutrikimai nustatyti 54,8 %, о kepenų cirozės grupėje MHE ¬ 71,0 % tiriamųjų asmenų. Kognityvinius sutrikimus predisponuoja trumpesnė mokymosi trukmė, fibrozės laipsnis, dvigubas etiologinis veiksnys, amžius ir lytis įtakos neturi. Lėtinio hepatito grupėje kognityviniai sutrikimai koreliuoja su IKT rodikliais ir kepenų fermentų koncentracijos padidėjimu, o kepenų cirozių grupėje su IKT rodikliais ir IL-6 koncentracija kraujyje. Išvados: Kognityvinius sutrikimus sergant lėtiniu hepatitu ar... [toliau žr. visą tekstą]
3

Simulering och känslighetsanalys av ett pumpkraft-dagvattendammsystem : En utvärdering av potential för småskalig energilagring av solelsöverskott eller arbitrage / Simulation and sensitivity analysis of a PHES-stormwater pond system : An evaluation of potential as small-scale energy storage used for solar energy or arbitrage

Abrams, Philip January 2020 (has links)
The global move to more sustainable and renewable energy sources causes increased fluctuations in theelectric market. That fact combined with the Swedish regulations on micro producers make high levels ofself-use critical and have increased the interest in energy storage of energy from intermittent sources.Cooperation with Eksta AB have provided the opportunity to evaluate an innovative energy storage conceptfor a future exploitation area of around 17,2 hectares planned residential and urban area. This bachelorthesis studies the potential of using stormwater management ponds for small-scale energy storage in theform of pumped hydro energy storage (PHES). The focus is on storage of surplus energy from a solarenergy system designed for micro production and local energy supply. However, it also evaluates thepotential of using the equivalent dimensions for energy storage which storage level only change whenbuying or selling electricity at market prices for arbitrage purposes.Potential in the form of financial benefit and increased self-use of solar energy are studied through aquantitative methodology that, in the case of storing surplus energy from a solar system, use a simulationmodel developed for this thesis that takes Eksta´s contractual electric specifications into account. Toevaluate the case of energy storage for arbitrage a simulation model is used in the form of an algorithmbaseddrive strategy named “Optimal”, which has been recreated from research in the field of energy storageand drive strategies. The level of innovation is high on account of including such as energy additions to thestorage from rain water management, energy losses from dispersion of stored stormwater to surroundingground layers, it´s novel focus on a stormwater pond for energy storage, the rarely studied combination ofPHES and small scale solar systems and finally that the dimensions of the pump and turbine that is neededin PHES is based on PaT (pump as turbine) technology, allowing the reverse drive of a centrifugal pumpto operate as a turbine.Sensitivity analysis is included to increase the understanding of PHES-stormwater systems in the case of Eksta and as a concept for energy storage. The work also includes a brief examination of relevant regulationsin order to supply a wider perspective.The result shows that the implementation of a PHES-stormwater system during the years 2018 and 2019increased the self-use of generated solar energy by 28,59 % and provide the joint financial benefit of 5989SEK. The simulation model of energy storage for arbitrage during the years 2018 and 2019 resulted in thecombined financial benefit of 699 SEK when “Optimal” operation strategy is used and 678 SEK with apractically applicable operation strategy.The main conclusion is that PHES-stormwater systems as an energy storage for small-scale solar surplushas high potential to increase the self-use of solar energy but relatively low potential to increase the financialbenefits of small-scale solar systems. From the sensitivity analysis it can be concluded that the simulatedPHES-stormwater system is sensitive to small and medium ranged changes in storage capacity, efficiency,rate of dispersion, set electrical buying price and selectivity of which hours to empty the storage. This whilebeing generally insensitive to small and medium ranged variations in installed peak effect of the solar system,filling/emptying time and the relative size of the turbine compared to the pump.The conclusion from the simulation of arbitrage application is that the potential for financial benefit inthese circumstances is extremely low. The sensitivity analysis lead to the conclusion that the system issensitive to small and medium ranged variations in storage capacity, efficiency, filling/emptying time andmarginal operation costs.Besides the limited financial benefit, other potential hindrances may be the legality of connecting the systemelectrically, lack of financial benefits given to larger but still small-scale solar systems and the eventuality ofdisrupting the main function of the stormwater pond, which is purifying stormwater.
4

Utilizing Energy Storage Applied on Floating Wind Turbine Economics Using a Spot-Price Based Algorithm

Johansson, Jim January 2017 (has links)
In this paper, a new algorithm for utilizing energy storage is proposed and applied on floating wind turbine economics. The proposed algorithm’s decision making on storing energy or selling electricity onto the grid is based on the electricity price, which makes it unique and different from similar algorithms. From the literature review, it was concluded Ocean Renewable Energy Storage to be most suitable with the Spar-Type and Semi-Submersible floating wind turbine to which the paper is based upon. The objective of this paper is to find the suitable ratio of energy storage versus wind farm, find the product of increase in wholesale, and evaluate whether the proposed method makes the hybrid economically sound. The algorithm was applied on spot-price data from Denmark due to its large share of wind energy with wind data from off the coast of Morro Bay in California, USA. Additionally, a sensitivity analysis is applied to evaluate to energy storage cost impact as well as evaluate the algorithm by lowering the required energy storage size.   Using the algorithm, the wind farm must account for nine days’ worth of energy production with a product of energy storage versus wind farm ratio of 1.42. The wholesale price increased with 11.9-21.5% for the four years studied, however, all financial results favored not utilizing energy storage. By the results derived from the sensitivity analysis, it was concluded that with future cost reductions, the algorithm will still favor no energy storage. However, by fine tuning the algorithm to reduce the need for storage, positive financial result might be achievable. The key to achieve a profitable result seems to rely on minimizing the need for energy storage, to which the proposed algorithm fail to achieve. Conclusively, spot-price decision-based energy storing is not economically sound.
5

New modelling and simulation methods to support clean marine propulsion

Grant, Michael 24 August 2021 (has links)
The marine industry has increased its adoption of pure-electric, diesel-electric, and other non-traditional propulsion architectures to reduce ship emissions and fuel consumption. While these technologies can improve performance, the design of a propulsion system becomes challenging, given that no single technology is superior across all vessel types. Furthermore, even identical ships with different operating patterns may be better suited to different propulsion technologies. Addressing this problem, previous research has shown that if key elements of a vessel's operational pro file are known, simulation and optimization techniques can be employed to evaluate multiple propulsion architectures and result in a better propulsion system design and energy management strategy for a given vessel. While these studies have demonstrated the performance improvements that can be achieved from optimizing clean marine propulsion systems, they rely on vessel operational profiles obtained through physical measurement from existing ships. From a practical point of view, the optimization of a vessel's propulsion system needs to occur prior to a vessel's construction and thus precludes physical measurement. To this end, this thesis introduces a marine simulation platform for producing vessel operational profiles which enable propulsion system optimization during the ship design process. Core subsystem modules are constructed for simulating ship motions in 3 degrees of freedom and result in operational profile time-series, including propulsion power. Data is acquired from a benchmark vessel to validate the simulation. Results show the proposed approach strikes a balance between speed, accuracy, and complexity compared with other available tools. / Graduate

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