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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.
371

Application of HHT to temperature variations at the thermal outlet of Third Nuclear Power Station

Wu, Wei-lih 22 March 2005 (has links)
Nan Wan is a half-closed embayment in the most southern part of Taiwan. While facing the Luzon Strait, it also connects to the Pacific Ocean in its southeast, and is adjacent the Taiwan Strait and the South China Sea . In view of general oceanic circulation, Nan Wan Bay happens to lie to the rim of South China Sea circumfluence and Kuroshio where a variety of water mass exchange has taken place, causing saline intrusion and mixed of water. Seasonal variation and tidal fluctuations also contribute to the exchange of water masses. The Third Nuclear Power Station of Taiwan Power Company is located in Nan Wan with its thermal discharge outlet adjacent to Maobitou to the west of the bay in order to minimize the effect of warm water discharge on the local marine ecology and coral . A long-term monitoring program on water temperature and other environmental factors has been set up implemented .this research report will first describe the archives regarding the hydrology in Nan Wan in support of monitoring the process in temperature variation . Previous research efforts are found somehow unable reveal precisely the physical mechanism leading to water temperature variations in the bay, due to limited facilities, short of information or poor analytical tools. This report adopts 14 records of water temperature at the thermal outlet of the Third Nuclear Power Station for signal analysis. As to non-linear and unstable data analysis, it is based on the Hilbert-Huang Transform. HHT includes Empirical Mode Decomposition, EMD which could decompose the raw data into numerous Intrinsic Mode Function, IMF. It is allowed to comprehend the main causes for the rising and dropping of water temperature based on the variation of spectroscopy by transferring through Hilbert and analyzing via IMF. Furthermore, the characteristic of each quantity could be developed according to the quantities acquired from the former method of HHT. The analytical report of water temperature covers 14 records dating from 1999 to 2003. In light of the analytical report, tide and wind account for the main cause of the temperature variation in waters while demanding information to ensure whether it is influenced by other factors like internal waves, water masses or landforms, etc. In addition, the report compares the difference in the same of data between FFT and HHT and moreover concludes the advantages and disadvantages as reference for researches.
372

KNOWLEDGE-BASED GLOBAL COMPETENCE AND ITS DETERMINANTS: AN INTEGRATIVE FRAMEWORK

Yu, Christina 05 July 2005 (has links)
As the traditional sources of competitive advantage can no longer provide a sustainable edge for business; the contemporary approach to global business strategy point to core competencies, invisible assets, and organizational capabilities as key factors influencing MNC¡¦s long-term success in global markets. An organization¡¦s intellectual assets are said to be a pack of knowledge under that firm¡¦s ownership or control, through services and the embodiment in firm¡¦s outputs to flow over time period. Knowledge especially has become the most strategically important resource and the potential to compete for advantages among MNCs to advance themselves in the information-driven societies. Derived from theoretical origins of resource-based view and behavioral perspective, an integrative framework from a sample set of 129 further concludes six determinants that enable MNC to build layers of knowledge-based global competence to compete and sustain advantages globally using structural equation modeling (SEM). Human interface, ISO, and parent innovation are found to have direct effect to firm¡¦s knowledge-based global competence, while IT, transnational innovation, and substantial investment in human capital are found to link indirectly through mediating effect of learning culture. From the resource perspective of the firm, as emerging country in its early phase of internationalization as Taiwan, local capabilities for knowledge innovation at host await to be developed over time and hence focal units rely on knowledge inflows from parent to assist their needs. Such interdependence between globally linked and locally leveraged for innovation makes externalized knowledge important for effective knowledge diffusion across network of subsidiaries aside from use of personnel flows for transferring implicit knowledge, IT for transferring explicit knowledge, and ISO for transferring codified knowledge, each requires good integration mechanisms to keep culture, language, and communication barriers to the minimum in cross-cultural settings. Investment in human capital and implementation of learning culture can benefit company enormously from movement of people either horizontally or vertically in terms of learning and sharing through socialization, and building a network of cross-functional interdependence for transferring knowledge, expertise, and sets of common goals and values for synergy.
373

The Study of Pitting Inspection in Pipes Using Guided Waves T(0,1) Mode

Yang, Jia-wei 01 January 2010 (has links)
Using ultrasonic guided waves can achieve long range inspection along the pipeline rapidly. The presence of defect or other features on the pipe were identified by analyzing the reflected echoes as well as mode conversion phenomena. However, it is difficult for guided wave to find a minor corrosion, such as pitting. Therefore, a study of the reflection of torsional T(0,1) mode from pits on the pipe has been carried out and an advanced signal processing method wavelet transform is adopted to process the reflected echoes in this study. In order to understand that characteristic of the reflected echoes of pits, the propagation of guided wave T(0,1) through pits was simulated by the finite element method. The frequency response of the signal reflected from the pits with different sizes was discussed both by finite element method and experimental method. Then, we discuss two types of pitting including regular- distributed pitting and the random-distributed pitting. We not only discuss the relation between the axial length of regular pitting and wave length of the T(0,1) mode, but also the reflected singal of four random pittings. The experiments were performed on 3 inch carbon steel pipe for measuring the reflected signals from different pittings with different frequencies. The results of the simulation, indicate that the wave was easily scattered by pitting because the shape of geometry. It is the reason of reducing the amplitude of reflected signals. To receive a dominate signal reflected from pitting, the excitation with higher frequency was choosen within the frequency range of interest. The experimental results indicate that the signals would be too weak to be detected by guided waves when the estimated cross sectional loss of the pitting is less than 2 percent. However, the results after wavelet transform showed the feasibility of improving the abilities of detecting minor pitting. In the case of regular pitting, the maximu value of the reflected signal appeared when the axial length of the pitting equals to the 66 % of the wavelength. It is because the constructive interference. The mode conversion phenomena is another behavior of the reflected signal cased by the non-axissymetric geometry of the pitting. As for the random pitting, The reflected echo shows different behavior with the regular pitting. The amplitude of the signal is bigger with lower frequency we use. The different level of random pitting on the pipe were also identified successfully by wavelet transform. Understanding the phenomena of interaction between the guided wave and the pitting is helpful to the guided wave inspection.
374

Use and Development of Computational Tools in Drug Discovery: From Small Molecules to Cyclic Peptides

Santiago, Daniel Navarrete 01 January 2012 (has links)
The scope of this work focuses on computationally modeling compounds with protein structures. While the impetus of drug discovery is the innovation of new therapeutic molecules, it also involves distinguishing molecules that would not be an effective drug. This can be achieved by inventing new tools or by refining old tools. Virtual screening (VS, also called docking), the computational modeling of a molecule in a receptor structure, is a staple in predicting a molecule's affinity for an intended target. In our Virtual Target Screening system (also called inverse-docking), VS is used to find high-affinity targets, which can potentially explain absorption, distribution, metabolism, and excretion (ADME) of a molecule of interest in the human body. The next project, low-mode docking (LD), attempts to improve VS by incorporating protein flexibility into traditional docking where a static receptor structure has potential to produce poor results due to incorrectly predicted ligand poses. Finally, VS, performed mostly on small molecules, is scaled up to cyclic peptides by employing Monte Carlo simulations and molecular dynamics to mimic the steps of small molecule VS. The first project discussed is Virtual Target Screening (also called inverse-docking) where a small molecule is virtually screened against a library of protein structures. Predicting receptors to which a synthesized compound may bind would give insights to drug repurposing, metabolism, toxicity, and lead optimization. Our protocol calibrates each protein entry with a diverse set of small molecule structures, the NCI Diversity Set I. Our test set, 20 kinase inhibitors, was predicted to have a high percentage of kinase "hits" among approximately 1500 protein structures. Further, approved drugs within the test set generally had better rates of kinase hits. Next, normal mode analysis (NMA), which can computationally describe the fundamental motions of a receptor structure, is utilized to approach the rigid body bias problem in traditional docking techniques. Traditional docking involves the selection of a static receptor structure for VS; however, protein structures are dynamic. Simulation of the induced fit effect in protein-ligand binding events is modeled by full articulation of the approximated large-scale low-frequency normal modes of vibration, or "low-modes," coupled with the docking of a ligand structure. Low-mode dockings of 40 cyclin dependent 2 (CDK2) inhibitors into 54 low-modes of CDK2 yielded minimum root-mean-square deviation (RMSD) values of 1.82 – 1.20 Å when compared to known coordinate data. The choice of pose is currently limited to docking score, however, with ligand pose RMSD values of 3.87 – 2.07 Å. When compared to corresponding traditional dockings with RMSD values of 5.89 – 2.33 Å, low-mode docking was more accurate. The last discussion involves the rational docking of a cyclic peptide to the murine double minute 2 (MDM2) oncoprotein. The affinity for a cyclic peptide (synthesized by Priyesh Jain, McLaughin Lab, University of South Florida), PJ-8-73, in MDM2 was found to be within an order of magnitude of a cyclic peptide from the Robinson Lab at the University of Zurich in Switzerland. Both are Β-hairpin cyclic peptides with IC50 values of 650 nm and 140 nm, respectively. Using the co-crystalized structure of the Robinson peptide (PDB 2AXI), we modeled the McLaughlin peptide based on an important interaction of the 6-chloro-tryptophan residue of the Robinson peptide occupying the same pocket in MDM2 as the tryptophan residue by the native p53 transactivation helical domain. By preserving this interaction in initial cyclic peptide poses, the resulting pose of PJ-8-73 structure in MDM2 possessed comparable active site residue contacts and surface area. These protocols will aid medical research by using computer technology to reduce cost and time. VTS utilizes a unique structural and statistical calibration to virtually assay thousands of protein structures to predict high affinity binding. Determining unintended protein targets aids in creating more effective drugs. In low-mode docking, the accuracy of virtual screening was increased by including the fundamental motions of proteins. This newfound accuracy can decrease false negative results common in virtual screening. Lastly, docking techniques, usually for small molecules, were applied to larger peptide molecules. These modifications allow for the prediction of peptide therapeutics in protein-protein interaction modulation, a growing interest in medicine. Impactful in their own ways, these procedures contribute to the discovery of drugs, whether they are small molecules or cyclic peptides.
375

Dynamic buckling of thin metallic rings under external pressure

Mainy, Aurélien 19 July 2012 (has links)
The main aim of this thesis is to gain insight through experiments into how the deformation characteristics of a thin ring made of a metallic material such as aluminum depend on the strain-rate. More precisely, this study investigates the buckling behavior of thin metallic rings subjected to a dynamic radial compressive loading. To do so, a total of twelve experiments were performed: three experiments for each of four load levels. The specimens used were aluminum 6061-O circular rings, having a mean radius of 15.5 mm with a radius-to-thickness ratio of 31. The external pressure acting on the specimens was created via electromagnetic induction following a rapid discharge of high voltage through a solenoid that was specially manufactured to interact with the ring specimen. This created a magnetic field that interacted with the specimen and therefore set a pressure on it. Three experiments were performed for each of the following charge levels: 2 kV, 3 kV, 4 kV and 5 kV. These experiments created maximum external pressures in the specimens that varied between 7 MPa and 38 MPa. The dynamic response of the ring specimens was recorded using a digital high-speed camera; analyses of the images revealed the initial uniform radial acceleration of the rings followed by the onset and evolution of dynamic buckling. The buckling response of the aluminum rings revealed that several different wave lengths (or buckling modes) can be observed simultaneously. These wave lengths correspond to measured mode numbers between 3 and 44, depending on the rate of change of the applied loading with the higher modes selected at higher strain-rates. Superposition of several pictures taken at different times during the experiment shows that as the ring deforms, the buckling waves stay within the same angular sector, keeping the same mode numbers they initially selected all the way during deformation. Numerical simulations were performed with the finite element program ABAQUS and validated the observation that several different buckling modes appear simultaneously in the rings and that their localizations are governed by material and geometric imperfections in the specimens. / text
376

Modal Shift Forecasting Models for Transit Service Planning

Idris, Ahmed 09 January 2014 (has links)
This research aims at developing a better understanding of commuters preferences and mode switching behaviour towards local transit for work trips. The proposed methodological approach incorporates three main stages. The first introduces a conceptual framework for modal shift maximized transit route design model that extends the use of demand models beyond forecasting transit ridership to the operational extent of transit route design. The second deals with designing and implementing a socio-psychometric COmmuting Survey for MOde Shift (COSMOS). Finally, the third stage focuses on developing econometric choice models of mode switching behaviour towards public transit. Advanced mode shift models are developed using state-of-the-art methodology of combining Revealed Preference (RP) and Stated Preference (SP) information. The results enriched our understanding of mode switching behaviour and revealed some interesting findings. Some socio-psychological variables have shown to have strong influence on mode shift and improved the models in terms of fitness and statistical significance. In an indication of the superiority of the car among other travel options, strong car use habit formation was realized for car drivers, making it hard to persuade them to switch to public transit. Further, unlike conventional choice models, the developed mode shift models showed that travel cost and in-vehicle travel time are of lower importance compared to other transit Level of Service (LOS) attributes such as waiting time, service reliability, number of transfers, transit technology, and crowding level. The results also showed that passengers are more likely to shift to rail-based modes (e.g. LRT and subway) than rubber-tyred modes (e.g. BRT). On the other hand, the availability of park-and-ride facilities as well as both schedule and real-time information provision did not appear to be significant for mode switching to public transit for work trips. This research provides evidence that mode shift is a complex process which involves socio-psychological variables beside common socio-demographic and modal attributes. The developed mode switching models present a new methodologically sound tool for evaluating the impacts of alternative transit service designs on travel behaviour. Such tool is more desirable for transit service planning than the traditional ones and can aid in precisely estimating transit ridership.
377

Modal Shift Forecasting Models for Transit Service Planning

Idris, Ahmed 09 January 2014 (has links)
This research aims at developing a better understanding of commuters preferences and mode switching behaviour towards local transit for work trips. The proposed methodological approach incorporates three main stages. The first introduces a conceptual framework for modal shift maximized transit route design model that extends the use of demand models beyond forecasting transit ridership to the operational extent of transit route design. The second deals with designing and implementing a socio-psychometric COmmuting Survey for MOde Shift (COSMOS). Finally, the third stage focuses on developing econometric choice models of mode switching behaviour towards public transit. Advanced mode shift models are developed using state-of-the-art methodology of combining Revealed Preference (RP) and Stated Preference (SP) information. The results enriched our understanding of mode switching behaviour and revealed some interesting findings. Some socio-psychological variables have shown to have strong influence on mode shift and improved the models in terms of fitness and statistical significance. In an indication of the superiority of the car among other travel options, strong car use habit formation was realized for car drivers, making it hard to persuade them to switch to public transit. Further, unlike conventional choice models, the developed mode shift models showed that travel cost and in-vehicle travel time are of lower importance compared to other transit Level of Service (LOS) attributes such as waiting time, service reliability, number of transfers, transit technology, and crowding level. The results also showed that passengers are more likely to shift to rail-based modes (e.g. LRT and subway) than rubber-tyred modes (e.g. BRT). On the other hand, the availability of park-and-ride facilities as well as both schedule and real-time information provision did not appear to be significant for mode switching to public transit for work trips. This research provides evidence that mode shift is a complex process which involves socio-psychological variables beside common socio-demographic and modal attributes. The developed mode switching models present a new methodologically sound tool for evaluating the impacts of alternative transit service designs on travel behaviour. Such tool is more desirable for transit service planning than the traditional ones and can aid in precisely estimating transit ridership.
378

Design And Construction Of A Cw Mode Nd:yag Laser Prototype.

Eryilmaz, Ertan 01 August 2004 (has links) (PDF)
In this thesis a theoretical background of Nd:YAG lasers has been presented and key parameters of a design have been stated. Both pulsed mode and CW mode designs have been made / a 500mJ xenon flash lamp has been investigated as the pulsed light source and a 500W tungsten halogen lamp has been used as the continuous light source for optical pumping. Closed cooling system has been constructed. De-ionized water has been used as coolant. The goal has been acomplished by constructing a CW mode prototype. The output power has been calculated. Dependence of output power to the reflectivity of output coupler is simulated and optimum reflectivity is calculated. Theoretical emission bands of Nd:YAG have been observed experimentally.
379

高強度GFRP積層板の層間はく離疲労き裂進展におよぼす混合モード比の影響

松原, 剛, MATSUBARA, Go, 西川, 弘泰, NISHIKAWA, Hiroyasu, 仁瓶, 寛太, NIHEI, Kanta, 田中, 啓介, TANAKA, Keisuke 12 1900 (has links)
No description available.
380

Die Trachtenbücher des 16. und 17. Jahrhunderts : eine Untersuchung zu ihrer Entstehung, Entwicklung und Bedeutung im kunsthistorischen Zusammenhang /

Gattineau-Sterr, Susanne. January 1996 (has links)
Diss. phil.-hist. Bern (kein Austausch). / Literaturverz.

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