• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 150
  • 115
  • 41
  • 18
  • 15
  • 14
  • 7
  • 6
  • 5
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 448
  • 53
  • 51
  • 47
  • 47
  • 41
  • 40
  • 38
  • 38
  • 37
  • 36
  • 35
  • 34
  • 33
  • 32
  • 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.
161

Modifikace provozních podmínek stroje ALIMAK - SCANDO / Modification of work conditions ALIMAK - SCANDO machine

Němec, Jan January 2011 (has links)
The theme of this master´s thesis with theme the modification of work conditions, it´s aim is to analyse existing and modified operating conditions of the machine and make their comparison. This work includes frame stress analysis, surface burdened by wind, the stability of the location and control of capacity at endurance.
162

Řešení technologie součásti chladicí věže / Solution technology of cooling tower component

Dobiáš, Radek January 2012 (has links)
The content of this diploma thesis is solution of production technology of cooling tower component. A model the cooling tower according to customer specifications is designed. There are selected 2 plates from steel construction that will be machined by plasma cutting. The technology of production of the plates is also proposed. Technical and economic evaluation of production compares 2 versions of plate production using unconventional metal cutting methods.
163

Variable Speed Chilled Water System Modeling & Optimization

Neal Louis Trautman (9192728) 04 August 2020 (has links)
The following thesis looks into modeling a chilled water system equipped with variable speed drives on different piece of equipment and optimization of system setpoints to achieve energy savings. The research was done by collecting data from a case-study and developing a system of component models that could be linked to simulate the overall system operation.
164

Thermo-Economic Analysis of a Solar Thermal Power Plant with a Central Tower Receiver for Direct Steam Generation

Desai, Ranjit January 2013 (has links)
No description available.
165

Enhancing the Thermo-Economic Performance of a Direct Steam Generation Solar Tower Power Plant through the Implementation of Steam Flow Control Strategies for Flexible Operation

Ellakany, Farid January 2014 (has links)
Above 90% of the current installed concentrating solar power plants are based on conventional steam-turbine cycles. The operation of steam turbines in these plants is distinctive when compared to traditional base-load power plants. The reason goes back to the intermittent nature of solar power which, in the absence of thermal energy storage or a back-up combustion boiler, forces plant operators to shut down the turbines during night time or at times of low solar radiation. Furthermore, such intermittency often leads to undesirable off-design turbine operating circumstances, either by load variations or changes on live-steam conditions.The present study examines the influence of implementing two operating strategies dealing with steam flow control as a function of incoming solar power for enhancing the thermo-economic performance of a direct steam generation solar tower power plant. The first one consists of a simultaneous high pressure turbine stage- and feed-water preheater bypass. This strategy is used during periods in which the solar radiation is higher than nominal. On these occasions, the plant is capable of generating a larger flow of steam, which allows for an increase in the power production when inserting the additional steam in the turbine bypass. On the other hand, the second operating strategy consists of using an additional feed-water preheater when the power from the field is lower than nominal. In this way, the feed water can reach a higher temperature prior entering the boiler, which is not only beneficial during times of cloud-passages, but also during the start-up process.A dynamic model of a direct steam generation solar tower power plant has been developed following design and operation specifications of an existing reference plant. The two proposed strategies were implemented to the reference model, then a whole year worth simulation was performed for both the reference and the modified models. Lastly, the thermodynamic and economic performance of both systems was measured for the purpose of comparison, by means of using KTH in-house tool DYESOPT. Results show that the implementation of the proposed strategies can enhance the economic viability of the systems by yielding a reduction of 8.7% on the levelized cost of electricity, mainly due to allowing achieving a 12% increase in the net electricity production.
166

Vertical Axis Wind Turbines : Tower Dynamics and Noise

Möllerström, Erik January 2015 (has links)
Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research. The work within this thesis is made in collaboration between the Department of Construction and Energy Engineering at Halmstad University and the Division for Electricity at Uppsala University. A 200 kW VAWT owned by the latter and situated close to Falkenberg in the southwest of Sweden has been the main subject of the research even if most learnings has been generalized to fit a typical vertical turbine. This particular turbine has a wooden tower which is semi-guy-wired, i.e. the tower is both firmly attached to the ground and supported by guy-wires. This thesis has two main topics both regarding VAWTs: eigenfrequency of the tower and the noise generated from the turbine. The eigenfrequency of a semi-guy-wired tower is studied and an analytical expression describing this is produced and verified by experiments and simulations. The eigenfrequency of the wire itself and how it is affected by wind load are also studied.  The noise characteristics of VAWTs have been investigated, both theoretically and by noise measurement campaigns. Both noise emission and frequency distribution of VAWTs has been studied. The work has resulted in analytical expressions for tower and wire eigenfrequency of a semi-guy-wired tower as well as recommendations for designing future towers for VAWTs. The noise emission of VAWTs has been studied and proven low compared to HAWTs. The noise frequency distribution of the 200 kW VAWT differs significantly from that of a similar size HAWTs with for example lower levels for frequencies below 3000 Hz.
167

Věžový dům – dominanta v Praze 13 – Nových Butovicích / Tower House - A Dominant in Prague 13 - Nové Butovice

Olekšák, Adam January 2019 (has links)
The city district Praha 13 – Nové Butovice has changed over the last 40 years. From the land of villages and fields have become the housing estates and bussiness centers. That is why the territory is still looking own identity. One of the tools to achieve it, is building a monunent. The project focuses on urban integration and architectural design of the new dominant in this district. The proposal is based on theoretical analyzes of the area and experimental process for determining the location and form of the building with its surroundings. It also solves operational, disposition and architectural expressions of the exterior and interior of the building.
168

Rozhledna / Watchtower

Bednár, Michal Unknown Date (has links)
ABSTRACT The task was to design and assess the supporting structure of the lookout tower. Material steel and wood. The lookout tower is 27.22 m high and decreases in height from the base of the srka. Construction system with continuous columns and horizontal reinforcement.
169

Advancements in geospatial monitoring of structures

Baldwin, Jordan Keith 12 May 2023 (has links) (PDF)
The need for advancements in geospatial monitoring of structures has evolved naturally as structures have become larger, more complex, and technology has continued to rapidly develop. Greater building heights generally lead to greater challenges for surveyors, limiting the practical use of traditional measurement methods. For this reason, a new complimentary method was developed and implemented to support elevation monitoring activities during construction of the Salesforce Tower in San Francisco, California. While some studies have explored the use of strain gauges to monitor strain development within individual members, the primary contribution of this work is that it presents a practical and proven to be implementable approach to estimating elevation changes throughout a multi-story reinforced concrete core wall tower during construction while utilizing strain measurements acquired at intermittent levels. Construction in urban landscapes has the potential to impact existing infrastructure. Identifying and mitigating any associated construction impacts is critical to public safety and construction progress. The development of Automated Motorized Total Stations (AMTS) has provided an effective means to monitor deformations in structures adjacent to construction activity. AMTS provides real time results so that movements may be immediately identified and addressed. However, the design, implementation, management, and analysis of these systems has frequently been problematic. Inadequate monitoring specifications have led to systems that fail to perform as intended even when project requirements were satisfied. A collection of monitoring specifications and AMTS projects have been reviewed to identify why certain problems have occurred and recommendations have been made to increase the probability of success on monitoring projects. A deformation monitoring approach that defines location specific threshold values based on a statistical analysis of baseline measurements is also presented in this dissertation. Identifying potential causes for monitoring specifications to fail to perform as intended and a deformation monitoring approach that defines location specific threshold values are secondary contributions of this dissertation.
170

JEDNA IDENTITA: Brno-Vídeň-Bratislava / JEDNA IDENTITA: Brno-Vienna-Bratislava

Bártová, Kristina January 2014 (has links)
The aim of this work is to analyze the problem of social alienation of two cultural centers of one region, rediscover a common link in between them and suggest a solution of their permanent coexistence through a specific architectural design.

Page generated in 0.0403 seconds