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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.
661

Technology advancement in intelligent buildings : a through preplanning process pertaining to long-term maintainability

Wilson, Michael Thomas 20 August 2004 (has links)
Innovation and new technologies are daily changing the characteristics of facilities as building owners are requiring more automated services, increased security is becoming more prevalent, and budget constraints are affecting facility operations. Therefore, additional avenues should be evaluated to reduce long-term costs by improving facility maintainability. The conclusions of these quarries should be incorporated into the design and preplanning phases as early as possible, as this is when the most impact can be made at the least expense. As it relates to this effort, preplanning refers to the project concept development and includes some initial aspects of the design. Preplanning for maintainability is one aspect that has historically not received much industry attention. This study considered the preplanning process as it pertains to maintainability, particularly for intelligent buildings, as this is the current trend in which building construction is heading. It limitedly considered the historic aspects of construction and automation, assessed the current situation and considered the projected future needs. Based on the expectations as to where future building intelligence will lead, it was ascertained that better preplanning should be incorporated into the construction process, especially as it pertains to maintainability.
662

Power Consumption Analysis of Rotorcraft Environmental Control Systems

Amaya Gonzalez, Hernan Andres 06 1900 (has links)
Helicopters have now become an essential part for civil and military activities, for the next few years a significant increase in the use of this mean of transportation is expected. Unlike many fixed-wing aircraft, helicopters have no need to be pressurized due to their operating at low altitudes. The Environmental Control Systems (ECS) commonly used in fixed-wing aircraft are air cycle systems, which use the engine compressor’s bleed flow to function. These systems are integrated in the aircraft from inception. The ECS in helicopters is commonly added subsequently to an already designed airframe and power plant or as an additional development for modern aircraft. Helicopter engines are not designed to bleed air while producing their rated power, due to this a high penalty in fuel consumption is paid by such refitted systems. A detailed study of the different configurations of ECS for rotorcraft could reduce this penalty by determining the required power resulting from each of the system configurations, and therefore recommend the most appropriate one to be implemented for a particular flight path and aircraft. This study presents the conducted analysis and subsequent simulation of the environmental control system in a selected representative rotorcraft: the Bell206L-4. This investigation seeks to optimize the rotorcraft’s power consumption and energy waste; by taking into consideration the cabin heat load. It consequently aims to minimize these penalties, achieving passenger comfort, an optimally moist air for equipment and a reduction in the environmental impact. For the purpose of this analysis a civil aircraft was chosen for a rotary-wing type. This helicopter was analysed with different air-conditioning packs complying with the current airworthiness requirements. These systems were optimized with the inclusion of different environmental control models, and the cabin heat load model, which provided the best air-conditioning for many conditions and mission scopes, thus reducing the high fuel consumption in engines and hence the emission of gases into the environment. Each of the models was computed in the Matlab-simulink® software. Different case studies were carried out by changing aircraft, the system’s configurations and flight parameters. Comparisons between the different systems and sub-systems were performed. The results of these simulations permitted the ECS configuration selection for optimal fuel consumption. Once validated the results obtained through this model were included in Rotorcraft Mission Energy Management Model (RMEM), a tool designed to predict the power requirements of helicopter systems. The computed ECS model shows that favourable reductions in fuel burn may be achievable if an appropriated configuration of ECS is chosen for a light rotorcraft. The results show that the VCM mixed with engine bleed air is the best configuration for the chosen missions. However, this configuration can vary according to the mission and environment.
663

A Novel Ultrasonic Method to Quantify Bolt Tension

Martinez Garcia, Jairo Andres 01 January 2012 (has links)
The threaded fasteners are one of the most versatile methods for assembly of structural components. For example, in bridges large bolts are used to fix base columns and small bolts are used to support access ladders. Naturally not all bolts are critical for the operation of the structure. Fasteners loaded with small forces and present in large quantities do not receive the same treatment as the critical bolts. Typical maintenance operations such tension measurements, internal stress checking or monitoring of crack development are not practical due to cost and time constrains. Although failure of a single non-critical fastener is not a significant threat to the structure's stability, massive malfunction may cause structural problem such as insufficient stiffness or excessive vibrations. The health of bolted joints is defined by a single parameter: the clamping force (CF). The CF is the force that holds the elements of the joint together. If the CF is too low, separation and bolt fatigue may occur. On the other hand, excessive CF may produce damages in the structural members such as excessive distortion or breakage. The CF is generated by the superposition of the individual tension of the bolts. The bolt tension, also referred as bolt preload, is the actual force that is stretching the bolt body. Maintaining the appropriate tension in bolts ensures a proper CF and hence a good health of the joint. In this thesis, a novel methodology for estimating the tension in bolts using surface acoustic waves (SAWs) is investigated. The tension is estimated by using the reflection of SAWs created by the bolt head interference. Increments in the bolt tension raise the points of interaction between the waves and the bolt head (real area of contact), and hence the position of the reflective boundaries. The variations are estimated using the "conventional linear synthetic array" imaging technique. A singular transducer is actuated from predefined positions to produce an array of signals that are subsequently arranged and added to construct an acoustic image. Three sets of experiment are presented in this research for validating the proposed concept: tension estimation of a ¼ inch stainless steel bolt, a ½ inch stainless steel bolt and ¼ inch grade 8 bolt. Acoustic images of the surface of the clamped plate illustrate a clear trend in the position of the reflective boundary when torque is changed. In all cases, the torque increments increase the real area of contact and therefore the position of the reflective boundary. As expected, the real area of contact grew from the bolt head center to the perimeter, which causes an effect of apparent movement of the boundary. This research proves the potential of the ultrasonic imaging methodology to measure applied tension. The result showed that the system can be used to successfully inspect tension in bolts of ½ and ¼ inches. The methodology investigated in this thesis is the first steps towards the development of bolt tension sensor based on surface acoustic waves.
664

Shelf-scale Mapping of Fish Distribution Using Active and Passive Acoustics

Wall, Carrie Christy 01 January 2012 (has links)
Fish sound production has been associated with courtship and spawning behavior. Acoustic recordings of fish sounds can be used to identify distribution and behavior. Passive acoustic monitoring (PAM) can record large amounts of acoustic data in a specific area for days to years. These data can be collected in remote locations under potentially unsafe seas throughout a 24-hour period providing datasets unattainable using observer-based methods. However, the instruments must withstand the caustic ocean environment and be retrieved to obtain the recorded data. This can prove difficult due to the risk of PAMs being lost, stolen or damaged, especially in highly active areas. In addition, point-source sound recordings are only one aspect of fish biogeography. Passive acoustic platforms that produce low self-generated noise, have high retrieval rates, and are equipped with a suite of environmental sensors are needed to relate patterns in fish sound production to concurrently collected oceanographic conditions on large, synoptic scales. The association of sound with reproduction further invokes the need for such non-invasive, near-real time datasets that can be used to enhance current management methods limited by survey bias, inaccurate fisher reports, and extensive delays between fisheries data collection and population assessment. Red grouper (Epinephelus morio) exhibit the distinctive behavior of digging holes and producing a unique sound during courtship. These behaviors can be used to identify red grouper distribution and potential spawning habitat over large spatial scales. The goal of this research was to provide a greater understanding of the temporal and spatial distribution of red grouper sound production and holes on the central West Florida Shelf (WFS) using active sonar and passive acoustic recorders. The technology demonstrated here establishes the necessary methods to map shelf-scale fish sound production. The results of this work could aid resource managers in determining critical spawning times and areas. Over 403,000 acoustic recordings were made across an approximately 39,000 km2 area on the WFS during periods throughout 2008 to 2011 using stationary passive acoustic recorders and hydrophone-integrated gliders. A custom MySQL database with a portal to MATLAB was developed to catalogue and process the large acoustic dataset stored on a server. Analyses of these data determined the daily, seasonal and spatial patterns of red grouper as well as toadfish and several unconfirmed fish species termed: 100 Hz Pulsing, 6 kHz Sound, 300 Hz FM Harmonic, and 365 Hz Harmonic. Red grouper sound production was correlated to sunrise and sunset, and was primarily recorded in water 15 to 93 m deep, with increased calling within known hard bottom areas and in Steamboat Lumps Marine Reserve. Analyses of high-resolution multibeam bathymetry collected in a portion of the reserve in 2006 and 2009 allowed detailed documentation and characterization of holes excavated by red grouper. Comparisons of the spatially overlapping datasets suggested holes are constructed and maintained over time, and provided evidence towards an increase in spawning habitat usage. High rates of sound production recorded from stationary recorders and a glider deployment were correlated to high hole density in Steamboat Lumps. This research demonstrates the utility of coupling passive acoustic data with high-resolution bathymetric data to verify the occupation of suspected male territory (holes) and to provide a more complete understanding of effective spawning habitat. Annual peaks in calling (July and August, and November and December) did not correspond to spawning peaks (March - May); however, passive acoustic monitoring was established as an effective tool to identify areas of potential spawning activity by recording the presence of red grouper. Sounds produced by other species of fish were recorded in the passive acoustic dataset. The distribution of toadfish calls suggests two species (Opsanus beta and O. pardus) were recorded; the latter had not been previously described. The call characteristics and spatial distribution of the four unknown fish-related sounds can be used to help confirm the sources. Long-term PAM studies that provide systematic monitoring can be a valuable assessment tool for all soniferous species. Glider technology, due to a high rate of successful retrieval and low self-generated noise, was proven to be a reliable and relatively inexpensive method to collect fisheries acoustic data in the field. The implementation of regular deployments of hydrophone-integrated gliders and fixed location passive acoustic monitoring stations is suggested to enhance fisheries management.
665

L’origine ed evoluzione della dimensione esterna della politica migratoria dell’Unione Europea: modi di governance, attori, istituzioni. / THE ORIGIN AND EVOLUTION OF THE EXTERNAL DIMENSION OF EU MIGRATION POLICY: MODES OF GOVERNANCE, ACTORS, AND INSTITUTIONS

CORTINOVIS, ROBERTO 06 March 2014 (has links)
L’obiettivo principale di questa tesi è di analizzare l’origine ed evoluzione della dimensione esterna della politica migratoria dell’Unione Europea. Attraverso un framework teorico che coniuga la letteratura sui ‘new modes of governance’ con quella riguardante il ‘rational-choice institutionalism’, questa tesi si propone di analizzare il sistema di governance in tre settori politici che rientrano nell’ambito della dimensione esterna: politica di riammissione, controlli esterni alle frontiere, e cooperazione con Paesi terzi concernente la gestione della migrazione legale. Sulla base delle premesse teoriche sopra indicate, questa tesi avanza due conclusioni principali. In primo luogo, si sostiene che l’evoluzione del sistema di governance nei tre casi presi in considerazione, lungi dal seguire un percorso lineare verso una sempre maggiore comunitarizzazione, ha al contrario dato luogo a sistemi di governance ‘ibridi’, che combinano cioè elementi vincolanti tipici del metodo comunitario con elementi caratteristici dei “new modes of governance”, incentrati sull’uso di soft law. In secondo luogo, si evidenzia il ruolo centrale rivestito dagli Stati Membri nello sviluppare tali sistemi di governance in accordo con due obiettivi prioritari: limitare l’autonomia delle istituzioni sovranazionali all’interno del processo decisionale e plasmare i risultati di tali politiche in accordo con le preferenze degli stessi Stati Membri. / The central aim of this thesis is to provide an account of the origin and evolution of the external dimension of EU migration policy. By means of a theoretical framework that combines new modes of governance and rational-choice institutionalism, this thesis analyses the systems of governance of three policy areas falling within the external dimension: readmission policy, external border controls and cooperation with third countries in the field of legal migration. On the basis of such theoretical premises, two central arguments are advanced. First of all, it is argued that the evolution of the system of governance in the three cases, far from following a linear path towards communitarization, has resulted in the adoption of mixed systems featuring both 'old' modes of governance in line with the traditional Community Method and 'new’ modes based on soft-law and non-binding commitments. Secondly, this thesis underlines the central role played by the Member States in devising those governance mechanisms in order to fulfil two main objectives: limiting the discretion of EU supranational institutions in the decision-making process and shaping policy outcomes according to their preferred policy options.
666

Smart offshore structure for reliability prediction process

Nwankwo, Cosmas Chidozie 09 1900 (has links)
A review of the developments within the field of structural reliability theory shows that some gaps still exist in the reliability prediction process and hence there is an urgent desire for improvements such that the estimated structural reliability will be capable of expressing a physical property of the given structure. The current reliability prediction process involves the continuous estimation and use of reliability index as a way of estimating the safety of any given structure. The reliability index β depends on the Probability Density Function (PDF) distribution for the wave force and the corresponding PDF of resistance from respective structural members of the given structure. The PDF for the applied wave force will depend on the PDF of water depth, wave angular velocity and wave direction hence the reliability index as currently practiced is a statistical way of managing uncertainties based on a general probabilistic model. This research on Smart Offshore Structure for Reliability Prediction has proposed the design of a measurement based reliability prediction process as a way of closing the gap on structural reliability prediction process. Structural deflection and damping are some of the measurable properties of an offshore structure and this study aims at suggesting the use of these measurable properties for improvements in structural reliability prediction process. A design case study has shown that a typical offshore structure can deflect to a range of only a few fractions of a millimetre. This implies that if we have a way of monitoring this level of deflection, we could use the results from such measurement for the detection of a structural member failure. This advocated concept is based on the hypothesis that if the original dynamic characteristics of a structure is known, that measurement based modified dynamic properties can be used to determine the onset of failure or failure propagation of the given structure. This technology could reveal the location and magnitude of internal cracks or corrosion effects on any given structure which currently is outside the current probability based approach. A simple economic analysis shows that the recommended process shows a positive net present value and that some $74mln is the Value of Information for any life extension technology that could reveal the possibility of extending the life of a given 10,000bopd production platform from 2025 to 2028.
667

A study of white-collar crime: the circumvention of the textiles export control system of Hong Kong

Lee, Wai-tak., 李偉德. January 1996 (has links)
published_or_final_version / Criminology / Master / Master of Social Sciences
668

Zum Langzeitverlauf und zur Mortalität von Benzodiazepinabhängigen im Vergleich zu Kontrollen. / Of the long-term course and mortality of benzodiazepin dependend patients in comparison to controls.

Wißmüller, Esther 29 October 2012 (has links)
No description available.
669

Verslo sistemų modelio analizė, panaudojant agregatinę schemą ir loginį programavimą / Analysis of business systems REA model using aggregate schema and logic programming

Janušauskaitė, Živilė 06 June 2006 (has links)
This work presents business process analysis methodology which consists of presentation of the business processes created on the ground of the Resource Event Agent model by means of Piece–Linear Aggregate approach. The aggregate specification is analyzing using first order predicate logic while checking correctness by resolution method using logic programming based language Prolog. The work is concluded with concrete example of analysis of Resource Event Agent model based business process using the aggregate approach. The novelty of this work PLA (Piece-Linear Aggregate) model and the software tools, created on the ground of PLA (Piece-Linear Aggregate), are used the first time for business processes analysis that is defined using REA formalism. The use of such integrated models allows performing the automated analysis of general and individual properties (completeness, deadlock freeness, termination or cyclic behavior, boundedness) of defined business processes. The main results are achieved: • The methodology, that consists of presentation of the business processes created on the ground of the Resource Event Agent model by means of Piece–Linear Aggregate approach. • Verification and validation of general and individual properties by using PLA and PROLOG language approach designed system that executes the analysis of aggregate specification. • Implementing internal accounting controls as constraints in relational algebra, SQL and PROLOG language. • Concrete... [to full text]
670

AERODYNAMICS AND CONTROL OF A DEPLOYABLE WING UAV FOR AUTONOMOUS FLIGHT

Thamann, Michael 01 January 2012 (has links)
UAV development and usage has increased dramatically in the last 15 years. In this time frame the potential has been realized for deployable UAVs to the extent that a new class of UAV was defined for these systems. Inflatable wing UAVs provide a unique solution for deployable UAVs because they are highly packable (some collapsing to 5-10% of their deployed volume) and have the potential for the incorporation of wing shaping. In this thesis, aerodynamic coefficients and aileron effectiveness were derived from the equations of motion of aircraft as necessary parameters for autonomous flight. A wind tunnel experiment was performed to determine the aerodynamic performance of a bumpy inflatable wing airfoil for comparison with the baseline smooth airfoil from which it was derived. Results showed that the bumpy airfoil has improved aerodynamics over the smooth airfoil at low-Re. The results were also used to create aerodynamic performance curves to supplement results of aerodynamic modeling with a smooth airfoil. A modeling process was then developed to calculate the aileron effectiveness of a wing shaping demonstrator aircraft. Successful autonomous flight tests were then performed with the demonstrator aircraft including in-flight aileron doublets to validate the predicted aileron effectiveness, which matched within 8%.

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