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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.
241

Problematika výjimečného trestu / The Issues of Exceptional Punishment

Kroo, Kateřina January 2021 (has links)
Problematics of extraordinary punishment - Abstract The aim of this thesis is to provide a comprehensive overview about a criminal law's legal institute of the extraordinary punishment. In this thesis I will comprise historical development of this legal institute and its connection with the death penalty. The first chapter is focused on defining the concept of punishment and its purpose, along with punishment theories. I will compare both theories with the extraordinary punishment. Subsequently I will deal with the historical development of punishment in the Czech republic in general, and than focus on the strictest penalties and finally I will represent historical develompent of the extraordinary punishment. The third chapter deals with the death penalty and its context. At the beginning I will shortly mention the history of the death penalty and than I will introduce situation in the world about the death punishment. Mostly this chapter analysis the arguments of supporter and opponents of the death penalty. In the fourth chapter I will deal with international sources that influenced the national adjustment of exceptional punishment primarily on the performance of imprisonment. The fifth part of my work will be based on the definition of substantive and processing provisions of the national adjustment of...
242

Zbytková životnost pecí v petrochemickém průmyslu / Residual Service Lifetime of Furnaces in Petrochemical Industry

Horsák, Libor January 2018 (has links)
The objectives of this work is residual lifetime of heaters in petrochemical industry. There is no comprehensive publication about this theme. This paper lists and describes the most of main phenomena that has to be taken into account in the process of determination of residual lifetime. This paper focuses on creep damage of a real heater based on deformation measurement. It describes some heater failures that could cause unplanned operation interruption however, appropriate intervention made possible safe heater operation until planned heater shutdown. No compact method is given how to determine heater residual lifetime, but a direction is given how a complex method of residual lifetime assessment of refinery heaters could be created.
243

Stanovení nejlepšího nástroje pro vystružování otvoru pro píst ve firmě Bosch Diesel, s.r.o. / Determining the best cutting tool for reaming the piston hole in Bosch Diesel company

Rauscher, Tomáš January 2018 (has links)
The main goal of this diploma thesis is to increase cost savings on cutting tools, which are used to ream piston hole inside the housing of CP3 diesel pump made by Bosch Diesel s. r. o. Diploma thesis is divided into a theoretical description of the issue, which is initial knowledge for machining tests, and experimental part, whose task it is to find a suitable reamer for this technological operation. Cost savings will be achieved by selecting suitable tool instead of the serial tool that has been used so far.
244

Studium stability vezikulárních systémů pomocí technik fluorescenční spektroskopie / Stability of vesicular systems using fluorescence spectroscopy techniques

Máčala, Jakub January 2020 (has links)
This thesis is focused on possibility of studying stability and fusion of catanionic vesicles with Förster resonance energy transfer. The mainly used technique was Time-Correlated single photon counting. Firstly, excitation and emission spectra of chosen probes were measured and donor-acceptor pairs were suggested: 5-hexadecanoylaminofluorescein with Octadecyl Rhodamine B, Bodipy 493/503 with rhodamine or DiI, perylene with fluorescein, DiO with DiI. Then, time-resolved measurements of suggested pairs from environment of catanionic vesicles with different content of cholesterol were made in order to track the FRET associated with fusion of vesicles. It was found out, that it is not possible to use DiO as a donor because of it’s inefficient solubilisation into vesicles. It is also not possible for Bodipy to be used as a donor, because of it‘s excimer formation. In case of using fluorescein as a donor, it was found, that there is ongoing homo-fret between fluorescein molecules. Thanks to this, fusion was tracked by addition of unstained vesicles. It was also possible to track fusion in longer period of time. Also perylene-fluorescein pair was found to be capable of tracking the fusion, but with the exception of vesicles with content of cholesterol of 43 mol. %, tracking of fusion was possible only in short period of time.
245

Wide Band-Gap Semiconductor Based Power Converter Reliability and Topology Investigation

Ni, Ze January 2020 (has links)
Wide band-gap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) have been widely investigated these years for their preferred operation at higher switching frequency, higher blocking voltage, higher temperature, with a compacter volume, in comparison with the traditional silicon (Si) devices. SiC MOSFETs have been utilized in photovoltaic systems, wind turbine converters, electric vehicles, solid-state transformers, more electric ships, and airplanes. GaN based transistors have also been adopted in the DC-to-DC converters in data centers, personal computers, AC-to-DC power factor correction converters for the consumer electronic adaptors, and DC-to-AC photovoltaic micro-inverters. The first part of this dissertation is regarding the lifetime modeling and condition monitoring for the SiC MOSFETs. Since SiC-based devices have different failure modes and mechanisms compared with Si counterparts, a comprehensive review will be conducted to develop accurate lifetime prediction, condition monitoring, and lifetime extension strategies. First, a novel comprehensive online updated system-level lifetime modeling approach will be presented. Second, to monitor the SiC MOSFET ageing, the typical degradation indicators of SiC MOSFET gate oxide will be investigated. Third, to measure the junction temperature, the dynamic temperature-sensitive electrical parameters for the medium-voltage SiC devices will be studied. The other part is the topology investigation of these emerging wide band-gap devices. A generalized topology that would leverage the advantages of the wide band-gap devices will be introduced and analyzed in detail. Following it is a new evaluation index for comparing different topologies with the consideration of the semiconductor die information. The topology and its derivatives will be utilized in the subsequent chapters for three applications. First, a 100 kW switched tank converter (STC) will be designed using SiC MOSFETs for transportation power electronic systems. Second, an updated STC topology integrating with the partial-power voltage regulation will be introduced for electric vehicle applications. Third, two novel single-phase resonant multilevel modular boost inverters will be designed based on the voltage-regulated STC. These topologies will be validated through designed prototypes. As a result, the high power density and high efficiency will be realized by combining the well-suited topologies and the advantages of the WBG devices.
246

Zpětné zotavení ve výkonových integrovaných obvodech / Reverse recovery in power integrated circuits

Šuľan, Dušan January 2016 (has links)
Předkládaná práce se zabývá parametrem “Reverse Recovery Time“ u polovodičových prvků a jeho vlivem na typické spínací obvody. V první části práce je objasněno co je “Reverse Recovery Time“ a jeho jednotlivé části. V další sekci je popsána jeho fyzikální podstata. Na konci teoretická části je rozebrán jeho efekt na spínací ztráty a doporučená metoda měření tohto parametru . Praktická část práce je zaměřena na simulace Dpdr45nres45 v prostředích Cadence a TCAD. Poslední část se zabývá návrhem obvodu na měření u reálných diod a samotným měřením diod a tranzistorů.
247

Absorber and Window Study – CdSexTe1-x/CdTe Thin Film Solar Cells

Hsu, Chih-An 17 January 2019 (has links)
CdTe an II-VI semiconductor has been a leading thin film photovoltaic material due to its near ideal bandgap and high absorption coefficient [1]. The typical thin film CdTe solar cells have been of the superstrate configuration with CdS (Eg-2.42eV) as the n-type heterojunction partner. Due to the relatively narrow bandgap of CdS, a wider bandgap n-type window layer has recently emerged as a promising substitute: alloys of MgyZn1-yO have been successfully used as the emitter or window layer. The benefits in the usage of MgyZn1-yO (MZO) are its tunable bandgap and wide optical spectrum on optoelectronic devices. Due to an increasing bandgap of the window layer, the carrier collection can be improved in the short wavelength range (<500 nm). In addition alloys of CdSexTe1-x (CST) have also been used in the absorber layer (i.e., CST/CdTe) for the fabrication of CdTe devices to improve the carrier collection and lifetime [2]. The lower bandgap of the CST alloy can lead to higher short-circuit current (JSC), but it can also result in lower open circuit voltage (VOC). Another critical aspect of the CdTe solar cell is the use of copper as a p-type dopant, which is typically incorporated in the cell during the fabrication of the back contact. The most challenging issue related to further advancing the CdTe solar cell efficiency is the relatively low level of p-type doping, which limits the VOC. Efforts to dope CdTe with group V dopants are yet to produce the desired results. ZnO has been used as an effective high resistivity transparent. When CdTe is deposited directly on sputtered ZnO, VOC of typically 500-600 mV is produced. Band alignment measurements indicate that a negative conduction band offset with CdS exists; alloying with MgO to produce MgyZn1-yO with a composition of y = 0.15 can produce a flat conduction band alignment with CdS. This material has an additional benefit for improving the energy bandgap of the MZO for better UV light transmission in the short wavelengths. By changing the magnesium content from y = 0 to 0.30 allowed researchers to make the tunable conduction band offset from a “cliff” to a “spike,” with both increased open-circuit voltage and fill factor as increasing magnesium compositions [3] — the bandgap gains as expected with increased magnesium composition. The large compositions (y > 0.30) of MgyZn1-yO cause the enormous spike result in S-kink in the IV measurement so that the FF decreases. Besides, due to the instability of MZO material, the fabrication process has to proceed carefully. The properties of CST films and cells were investigated as a function of Se composition (x), substrate temperature (TSUB), and ambient used during the CSS deposition. The higher ratio of Se in CST alloy causes the smaller grain structures and lower bandgap, which profoundly detrimental to the device performance (VOC). However, the CST can be deposited in various substrate temperatures and different inert ambient gas to improve the grain structure by utilizing the especial Close Space Sublimation (CSS) deposition system. Therefore, despite the fact that the CST (25% Se) has the optical bandgap (1.37eV), the improvement of grain structure can slightly increase the doping concentration and decrease the grain boundary (GBs) due to increased alloys grain size 3X larger, which is contributed to improving the VOC [4]. The study of higher ratio Se of CST alloy is significant to achieve the high efficiency polycrystalline CST/CdTe photovoltaic devices. The effect of Cu doping back contact in CdSexTe1-x (CST)/CdTe solar cells with varying amounts of Se (x) has been investigated. The Cu-based back contact was annealed at different thermal temperatures in order to vary the amount of Cu in-diffusion. Net p-type doping was found to increase as the back-contact annealing temperature increased. All cells exhibited a decrease in VOC with increased annealing temperature (i.e., higher Cu concertation), presumably due to a degradation of the lifetime with increased amounts of Cu [5]. However, cells with the highest Se composition appeared to exhibit a higher degree of tolerance to the amount of Cu – i.e., they exhibited a smaller loss in VOC with the increased amount of Cu. Extrinsic p-type doping of CdSeTe can be fabricated using two different experimental processes. Firstly, by using group I elements such as, Cu to substitute Cd, which is promising during the back contact process. Secondly, using group V (P, As, Sb) elements to substitute Te, and this is suitable for Cd-rich of intrinsic CdTe. Intrinsic CST alloy has lower hole density concentration as higher Se composition with limitation of the VOC. Thus, in order to increase the p-type net doping up to 1016 cm-3 the extrinsic P or As doping have been widely investigated recently. The research studies show the CST/CdTe devices lead to improve VOC up to 850 mV with higher hole density in higher Se compositions of As doped CST alloys. Nevertheless, the group V doped CdTe still cause the formation of compensating defects limits the upper boundary of dupability on the CdTe thin film solar cells. Even if a high hole density concentration is achieved for intrinsically-doped p-type CST/CdTe, it is believed the poor carrier lifetime in the CdTe side would still limit the VOC.
248

Made to Fade : An exploration of extending the lifetime of a garment through natural printing in combination with flat piece garment construction.

Tallvod, Lynn January 2020 (has links)
This work serves as an exploration of how garments life can be extended through the possibility of updating it post-use with natural pigment printing. Flat garment construction is explored for the possibility of taking garments apart to update them with print during their lifetime. The technique of naturally printing in combination with flat garment construction can potentially lead to garments that will change over time, dependent on the wearer which creates an emotionally durable design, writing the history of time into the garments.
249

Lifetime extension of offshore wind farms

Eriksson, Robert January 2022 (has links)
Renewable energy sources are in strong demand as the need for clean energy is increasing, driven by the need to reach the environmental targets. Offshore wind power is becoming an attractive source as the technology matures and cost decreases. With time all wind farms age and when the time comes one needs to consider end of life alternatives. The objective with this Thesis is to assess lifetime extension of offshore wind farms, with a focus on reliability, availability and maintenance. As of today there are few offshore wind farms reaching their end of life but one needs to be prepared. From the literature review it is clear that there is somewhat limited documentation around lifetime extensions. The reason for lifetime extension is to increase the return on investment (ROI) of the original project, with a limited additional investment. With capital expenditure (CAPEX) being a large part of the overall project cost it is beneficial to achieve more operational years to divide the cost over, one also need to consider increased operations and maintenance (O&amp;M) cost with aging assets. In this Thesis, a Reliability block diagram (RBD) model was developed in ReliaSoft BlockSim to calculate wind turbine failures, their associated downtime and O&amp;M costs to create an overview of the future behaviour and cost. To assess the wind farm economics a financial model was built, based on output from the RBD model, to evaluate the levelized cost of energy (LCOE) and internal rate of return (IRR) for several cases of lifetime extension. A case study was done for a generic wind farm of 30 wind turbines, assumed to be built around 2010 using 3.6MW rated turbines, to illustrate a relevant case. Focus was on O&amp;M cost, and it was assumed the structural integrity of the wind turbines would be maintained for the lifetime extension for up to 10 years.
250

Wireless Sensor Networks in Smart Cities : The Monitoring of Water Distribution Networks Case

Rong, Du January 2016 (has links)
The development of wireless sensor networks (WSNs) is making it possible to monitor our cities. Due to the small size of the sensor nodes, and their capabilities of transmitting data remotely, they can be deployed at locations that are not easy or impossible to access, such as the pipelines of water distribution networks (WDNs), which plays an important role in protecting environment and securing public health.   The design of WSNs for WDNs faces major challenges. Generally, WSNs are resource-limited because most of the sensor nodes are battery powered. Thus, their resource allocation has to be carefully controlled. The thesis considers two prominent problems that occur when designing WSNs for WDNs: scheduling the sensing of the nodes of static WSNs, and sensor placement for mobile WSNs. These studies are reported in the thesis from three published or submitted papers. In the first paper, the scheduling of sleep/sensing for each sensor node is considered to maximize the whole WSNs lifetime while guaranteeing a monitoring performance constraint. The problem is transformed into an energy balancing problem, and solved by a dynamic programming based algorithm. It is proved that this algorithm finds one of the optimal solutions for the energy balancing problem. In the second paper, the question of how the energy balancing problem approximates the original scheduling problem is addressed. It is shown that even though these two problems are not equivalent, the gap of them is small enough. Thus, the proposed algorithm for the energy balancing problem can find a good approximation solution for the original scheduling problem. The second part of the thesis considers the use of mobile sensor nodes. Here, the limited resource is the number of available such mobile nodes. To maximize the monitoring coverage in terms of population, an optimization problem for determining the releasing locations for the mobile sensor nodes is formulated. An approximate solution algorithm based on submodular maximization is proposed and its performance is investigated. Beside WDNs, WSN applications for smart cities share a common characteristic: the area to monitor usually has a network structure. Therefore, the studies of this thesis can be potentially generalized for several IoT scenarios. / <p>QC 20160419</p>

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