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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.
331

Reconfigurable Aerial Computing System: Design and Development

Gu, Yixin 08 1900 (has links)
In situations where information infrastructure is destroyed or not available, on-demand information infrastructure is pivotal for the success of rescue missions. In this paper, a drone-carried on-demand information infrastructure for long-distance WiFi transmission system is developed. It can be used in the areas including emergency response, public event, and battlefield. In years development, the Drone WIFI System has developed from single-CPU platform, twin-CPU platform, Atmega2560 platform to NVIDIA Jetson TX2 platform. By the upgrade of the platform, the hardware shows more and more reliable and higher performance which make the application of the platform more and more exciting. The latest TX2 platform can provide real time and thermal video transmission, also application of deep learning of object recognition and target tracing. All these up-to-date technology brings more application scenarios to the system. Therefore, the system can serve more people in more scenarios.
332

Návrh a realizace mikrovlnné směrové odbočnice / Design and realisation of microwave directional coupler

Nejedlý, Miroslav January 2010 (has links)
The diploma thesis deals with microwave directional coupler. The paper presents some of the microwave directional coupler and an analysis of bifurcations. The paper also discussed the various techniques of bifurcations and the bandwidth to which they are making. Proposal is implemented in two selected directional couplers and determining their size. They also performed using the selected simulation program selected two bifurcations. Furthermore, these couplers are made on the perimeter of the analyzer is verified by their actions and are verified by the actual parameters of the coupler.
333

Speciální reflektory pro širokopásmové dipólové antény / Special reflectors for wideband dipole antennas

Velička, Pavel January 2012 (has links)
The thesis is focused on special corrugated reflectors for ultra-wideband antennas. Corrugated reflectors are divided into a type H and a type E. Both these types are mutually combined. All those reflectors are simulated and subsequently analyzed. The thesis also deals with different types of broadband dipoles, which are completed by investigated types of reflectors. Created reflector antennas are then compared. For antennas exhibiting the best parameters, we performed simulations of the transmission between two antennas. For the simulations, we used CST Microwave Studio. Selected antennas were manufactured and measured. Consequent simulations were aimed to detect differences between the simulated and measured results.
334

Studie zvýšení rychlosti v úseku Boří les - Hrušovany nad Jevišovkou / Study of Speed Increasing for the Boří les - Hrušovany nad Jevišovkou Track Section

Grenar, Filip January 2014 (has links)
The aim of this work is to study track speed increase in section between Boří les – Hrušovany nad Jevišovkou – line Břeclav – Znojmo. In terms of this work directional and height adjustment is beig suggested. The ambition was to ensure basic accessibility of this area within existing range. The study was prepared and respects costs.
335

Obchvat obcí Želechovice nad Dřevnicí a Lípa / Bypass of Želechovice nad Dřevnicí and Lípa

Škrabal, Jiří January 2014 (has links)
The thesis is focused on the design of the northern bypass of the villages Želechovice nad Dřevnicí and Lipa. The reason for the study is excessive traffic intensity and with that associated noise intensity. The objective of study is drop of traffic in villages and faster and smoother passage of transit traffic continued toward the road I/49. Seven direction solutions were designed of which one was chosen for further solution. This solution was designed in two variants.
336

Vyhledávací studie silnice II/152 mezi Modřicemi a Ivančicemi / Location Study of The Road II/152 in Stage Modřice - Ivančice

Konečná, Tereza January 2015 (has links)
The Diploma thesis is devoted to working out the searching study for modernization of the road II/152 between the cities Modřice and Ivančice with connection of the existing infrastructure to the new transport solution. The aim was the improvement of the quality of transport, reduce the traffic in the municipalities and the noice related to it and the improvement of environment.Four variants were designed and the most suitable possibility was solved
337

Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation

Hellström, Pia January 2015 (has links)
The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a fully bleached birch (Betula verucosa) kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment with a monocomponent endoglucanase (FiberCare® R). The mechanical treatment to MFC was performed in a laboratory colloid mill or in a pilot high-pressure homogeniser and the pre-treated pulps as well as the produced MFCs were chemically and morphologically characterised. Additionally, the MFCs produced in the colloid mill were evaluated as strength enhancers in test sheets representing the middle ply of paperboard. From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. The increase in carbonyl groups could not be explained by the formation of new reducing end groups due to depolymerisation which indicates that carbonyl groups are introduced along the cellulose chain. The enzymatic pre-treatment as performed in this study caused less impact on the cellulosic material, i.e. resulted in a pulp with a higher DP and a much lower amount of carbonyl- and carboxylic groups compared with the Fenton pre-treated pulps. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically i.e. reached a higher specific surface area and a higher surface charge at a given mechanical treatment time compared to enzymatic pre-treated pulps and pulps not subjected to any pre-treatment. These findings were confirmed when MFCs were produced by homogenisation at high pressure in multiple passes; the birch kraft pulp was either pre-treated with Fenton’s reagent or the combined mechanic and enzymatic pre-treatment methodology used at the Centre Technique du Papier (CTP, France). By size fractionation, rheological measurements and scanning electron microscopy, it was revealed that Fenton pre-treatment resulted in MFC suspension containing a significantly higher proportion of small sized material (< 0.2 mm). When the MFCs were evaluated as strength enhancers in test sheets produced from a furnish consisting of a spruce (Picea abies) chemithermomechanical pulp, MFC and a retention system containing cationic starch and an anionic silica sol, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition. / The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a bleached birch kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment. Additionally, the MFCs evaluated as strength enhancers in test sheets representing the middle ply of paperboard. From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically indicating a potential to lower the energy consumption. When the MFCs were evaluated as strength enhancers in test sheets, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs at a given mechanical treatment time. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition.
338

Directional Emission of Light in Hyperbolic Metamaterials and Its Application in Miniature Polarimeter

Chen, Hongwei 26 September 2019 (has links)
No description available.
339

Accessibility of support structure in Topology Optimized Designs for Additive Manufacturing

Patil, Shriya Chetan January 2022 (has links)
No description available.
340

Schaktfri ledningsbyggnad : En kostnadsanalys mellan styrd borrning och konventionell schaktning / Trenchless pipeline installation : A cost analysis between directional drilling and traditional excavation

Andersson, Sophia, Jonsén, Oscar January 2019 (has links)
Styrd borrning är en schaktfri metod för att förlägga ledningar i mark. Examensarbetet har utförts i samarbete med Styrud Ingenjörsfirma AB som uppfattat en okunskap i branschen över prisbilden för styrd borrning. Syftet med arbetet är att utföra en kostnadsanalys för att beskriva hur styrd borrning står sig ekonomiskt mot konventionell schaktning. Arbetet undersöker även vilka faktorer som påverkar en eventuell ekonomisk brytpunkt, vilken i detta arbete definieras som den punkt när en viss metod blir det ekonomiskt gynnsamma alternativet. Studien har utformats för att så objektivt som möjligt belysa ämnet med utgångspunkten att göra metoderna jämförbara analytiskt. För att genomföra en analys har en beräkningsmodell skapats. Målet med modellen och dess utformning är att den enkelt skall gå att bygga vidare på och utvecklas i framtiden samt att användas av projektörer som en fingervisning tidigt i projekteringsstadiet. Från beräkningsmodellen har 70 fiktiva fall studerats. Resultatet visar att styrd borrning är billigare i 73% av fallen. I övriga fall tyder resultatet på att styrd borrning som metod generellt sett inte är så dyrt att övervägning att använda metoden försvinner. Genom resultat och analys dras slutsatsen att styrd borrning i de flesta fall står sig ekonomiskt starkt som alternativ till konventionell schaktning. / Horizontal directional drilling is a trenchless method used to install pipelines underground. This thesis is conducted in collaboration with Styrud Ingenjörsfirma AB, who perceived lacking knowledge within the industry regarding the financial aspects of directional drilling. The purpose of this thesis is to carry out a cost analysis that defines how directional drilling stands financially against traditional excavation. The study also intends to describe which factors that influence a possible economic breakpoint, in this study referring to when a certain method becomes the economically strongest alternative. This thesis has been carried out to as objectively as possible describe the topic focusing on making the methods analytically comparable. To carry out the analysis, an economic model has been created. The model and its design have been created in a manner that makes it easy to develop it in the future and aims to act as a guide for project planners to indicate which method to proceed with. From the economic model, 70 cases have been studied. The result shows that directional drilling is cheaper in 73% of the cases. In the rest of the cases, the result suggests that directional drilling as a method generally is not so expensive that consideration of using the method disappears. Through results and analysis, it is concluded that directional drilling in most cases is a strong alternative to traditional excavation from an economic standpoint.

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