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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.
291

Using Road Weather Information Systems (RWIS) to optimize the Scheduling of Load Restrictions on Northern Ontario's Low-Volume Highways

Baiz, Sarah January 2007 (has links)
Covering the Northern part of the Province, Ontario’s low-volume roads provide a link from remote resource areas to markets. Thus, preserving this transportation asset from the two main sources of pavement deterioration, namely traffic loading and the environment is extremely critical to the movement of goods and to the economy. In particular, Northern Ontario’s secondary highways are challenged by a combination of heavy, low frequency traffic loading and a high number of freeze-thaw cycles for which most of these highways have not been structurally designed. Therefore they experience environmental damage and premature traffic-induced deterioration. To cope with this issue, the Ontario Ministry of Transportation places Spring Load Restrictions (SLR) every year during spring-thaw. For economic reasons, the duration of SLRs is usually fixed in advance and is not applied proactively or according to conditions in a particular year. This rigidity in the schedule needs to be addressed, as it can translate into economic losses either when the payload is unnecessarily restricted or when pavement deterioration occurs. While the traditional approaches are usually qualitative and rely on visual observations, engineering judgment and historical records to make SLR decisions, the latest approaches resort to climatic and deflection data to better assess the bearing capacity of the roadway. The main intent of this research was to examine how the use of a predictor for frost formation and thawing could improve the scheduling of load restrictions by tracking the frost-strengthening and thaw-weakening of the pavement structure. Based on field data captured in Northern Ontario, and on a preliminary analysis that found good correlation between frost thickness in the roadway and Road Weather Information Systems (RWIS) variables, more advanced frost and thaw predictors were developed as part of this research and are presented herein. The report outlines how the model was developed, details the calculation algorithms, and proposes an empirical methodology for a systematic site-specific calibration. This research also involved several experimental and numerical tools, including the use of a Portable Falling Weight Deflectometer (PFWD) to estimate pavement strength during spring thaw, and the use of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to simulate the impact of SLR on the performance of typical Northern Ontario low volume roads.
292

One and Two-Dimensional Mass Spring Computational Model for Phononic Band Gap Analysis

Cao, Zhan John January 2009 (has links)
Computation model is presented for mass spring systems of one and two dimensional phononic band gap crystals and micro-electro-mechanical systems. The computation model is veri ed with existing work, and phononic band gap microelectro- mechanical systems are analyzed. Phononic band gap in the scienti c and industrial community is discussed. The motivation and the recent popular methods are discussed. The computation models are highlighted with their pros and cons and adequate computational applications. The one dimensional mass spring model is developed and the simulator operation is validated through comparison with the published simulation data in the original paper by J.S. Jensen et al.. Additionally, the one dimensional mass spring simulator is validated for a micro-electro-mechanical system band structure. The two dimensional mass spring model is developed, as well, the simulator operation is validated through comparison with the published simulation data in the original paper by J.S. Jensen et al.. The two-dimensional simulator is utilized to analyze solid square-shaped, hollow square-shaped, solid diamond-shaped, and hollow diamond-shaped inclusion micro-electro-mechanical band gap structures. The solid inclusion-based micro-electro-mechanical band gap results are compared with hollow inclusion-based micro-electro-mechanical structures.
293

Characterizing selectin-ligand bonds using atomic force microscopy (AFM)

Sarangapani, Krishna Kumar 14 July 2005 (has links)
The human body is an intricate network of many highly regulated biochemical processes and cell adhesion is one of them. Cell adhesion is mediated by specific interactions between molecules on apposing cell surfaces and is critical to many physiological and pathological processes like inflammation and cancer metastasis. During inflammation, blood-borne circulating leukocytes regularly stick to and roll on the vessel walls, which consist in part, adhesive contacts mediated by the selectin family of adhesion receptors (P-, E- and L-selectin). This is the beginning of a multi-step cascade that ultimately leads to leukocyte recruitment in areas of injury or infection. In vivo, selectin-mediated interactions take place in a hydrodynamic milieu and hence, it becomes imperative to study these interactions under very similar conditions in vitro. The goal of this project was to characterize the kinetic and mechanical properties of selectin interactions with different physiologically relevant ligands and selectin-specific monoclonal antibodies (mAbs) under a mechanically stressful milieu, using atomic force microscopy (AFM). Elasticity studies revealed that bulk of the complex compliance came from the selectins, with the ligands or mAbs acting as relatively stiffer components in the stretch experiments. Furthermore, molecular elasticity was inversely related to selectin length with the Consensus Repeats (CRs) behaving as Hookean springs in series. Besides, monomeric vs. dimeric interactions could be clearly distinguished from the elasticity measurements. L-selectin dissociation studies with P-selectin Glycoprotein Ligand 1 (PSGL-1) and Endoglycan revealed that catch bonds operated at low forces while slip bonds were observed at higher forces. These results were consistent with previous P-selectin studies and suggested that catch bonds could contribute to the shear threshold for L-selectin-mediated rolling By contrast, only slip bonds were observed for L-selectin-antibody interactions, suggesting that catch bonds could be a common characteristic of selectin-ligand interactions. Force History studies revealed that off-rates of L-selectin-sPSGL-1 (or 2-GSP-6) interactions were not just dependent on applied force, as has been widely accepted but in fact, depended on the entire history of force application, thus providing a new paradigm for how force could regulate bio-molecular interactions. Characterizing selectin-ligand interactions at the molecular level, devoid of cellular contributions, is essential in understanding the role played by molecular properties in leukocyte adhesion kinetics. In this aspect, data obtained from this project will not only add to the existing body of knowledge but also provide new insights into mechanisms by which selectins initiate leukocyte adhesion in shear.
294

The occurrence of the pharmaceuticals and personal care products (PPCPs) and illicit drugs in western Hengchun Peninsula and Kenting tourist area of Taiwan

Tu, Bo-Wen 26 September 2012 (has links)
This study investigated the spatial distribution and seasonal variation of pharmaceuticals and personal care products (PPCPs) and illicit drugs in western Hengchun peninsula and Kenting coastal tourist area in Taiwan. We used solid phase extraction (SPE) followed by liquid-chromatography tandem mass spectrometry (HPLC-MS/MS) to determine 22 PPCPs and 10 illicit drugs in water samples. The detected concentrations of PPCPs and illicit drugs ranged from below detection limit to 9350 ng/L, and the most frequently five detected compounds in this area were ampicillin (79%), codeine (63%), caffeine (62%), carbamazepine (61%) and pseudoephedrine (57%). The impact of the special event- Kenting music festival, such as ¡§spring scream¡¨ was also discussed in this study, and the results from PCA and HCA both showed that the concentrations and distributions of PPCPs and illicit drugs were affected by the tourists. In addition, two wastewater treatments plants (WWTPs) were also investigated for seven days during Kenting music festival period. The results indicated that WWTPs did not show enough removal efficiencies in Kenting tourist area during the special event. The impact of the PPCPs and illicit drugs to the aquatic environment and ecology still needs to be further monitored.
295

none

Haung, Mei-Lan 11 July 2005 (has links)
none
296

A Study on the Deformation and Stress Distributions of ACF/ACA on the Flip-Chip Packaging

Lin, Yen-hong 03 September 2006 (has links)
In this thesis, the contact behavior of the conduct particles in the anisotropic conductive film (ACF) packaging process is investigated. The thermal elastic-plastic finite element (FE) model is employed to simulate the contact process. The commercial MARC finite element method package is used in this work. Two contact models of the ACF packaging are studied : the single particle and the multiple-particles models. In the single particle model a simple axial symmetric FE model is used to simulate the variation of elastic-plastic deformations during packaging process. The effect of coating thickness on the contact deformation is discussed. To explore the effect of particle distribution on the contact deformation and the conduct behavior in the ACF packaging, the multiple-particles 3D model has also been studied. However, to overcome the computing difficulties introduced from huge degrees of freedom, the equivalent nonlinear springs are employed to stand for some conductive particles. The effect of particle distribution and particle parameters on the conductive behavior are studied. Results indicate that the conductive particle parameters may affect the conductive characteristics significantly in the ACF packaging process.
297

Analysis of Impact Effect to Varied Thickness of Golf Club Head

Wu, Shih-Ping, 26 July 2001 (has links)
ABSTRACT The substance of this study is to analyze the impact process between golf club head and golf ball by integrating the capability of the CAD software I-DEAS and the finite element analysis software LS-DYNA. The various golf club head can be created much easily by determined the dimension parameter in the variable-parameter characteristics of I-DEAS. The computational cost can be reduced by explicit central difference method of LS-DYNA. This study is to analyze the impact effect of varied thickness based on Taguchi method of experimentation and off-center hit in difference volume club head. After that, the hitting area, the sweet spot of club head and influencing factors of impact effect are discussed. It is expected that the findings of the study may provide engineers with some effective method to deal with golf club head design.
298

The System of Counties in the Period of Spring And Autumn, the System of Prefectures and the Placement of Officials in the Period of Warring States

Liu, Yi-hsiu 28 December 2009 (has links)
This thesis mainly discusses the System of Counties in the Period of Spring And Autumn, the System of Prefectures and the Placement of Officials in the Period of Warring States.It contains various countries' prefectures and counties' officers and the origin of the placement of officials, its changing conditions, as well as its development and the distributed situation.The study is focused on whether these systems were closely conneted to its time and various districts.
299

Shaping blended worship at Spring Valley Baptist Church in Columbia, South Carolina

McCollum, Rick. January 2000 (has links)
Thesis (D. Min.)--Northern Baptist Theological Seminary, 2000. / Abstract. Includes bibliographical references (leaves 172-178).
300

The Biogeochemistry of Submerged Coastal Karst Features in West Central Florida

Garman, Keith Michael 30 September 2010 (has links)
West Central Florida is a complex karst environment with numerous sinkholes, springs, and submerged cave systems. Many of these karst features are anchialine, located within the subterranean estuary where freshwater and saltwater mix. Water quality data and/or fauna data were obtained from twenty-one karst features and their associated cave systems. The anchialine karst environment of the study area has a wide range of habitats with measured salinities ranging from freshwater at <0.2 ppt to sulfidic, hypersaline water at 38.5 ppt and measured pH readings ranging from 6.39 in water impacted by sulfur oxidizing bacteria to 10.3 in an isolated room of a cave. Stygobitic crustaceans were identified in conduits extending beneath the Gulf of Mexico supporting the hypotheses that freshwater crustaceans could survive higher sea levels in freshwater conduits beneath saltwater. The fauna associated with the anchialine cave systems included Sabellidae and Polychaeta worms, hydroids, cnidarians and hydrobiid snails. Jewfish Sink, like other anaerobic marine basins that were submarine springs, has four zones: oxic zone, transition zone, upper anoxic zone and anoxic bottom water. The upper zones have seasonal water quality variations from winter cooling and sinking of surface water and changes in the microbial communities. Activity of sulfate reducing bacteria is carbon limited in the anoxic zones, where sulfate reduction is the major metabolic process, and primary production is phosphate limited in the oxic zones. Organic input from the Gulf of Mexico drives the bacterial anaerobic ecosystem, resulting in a “sulfide pump”, in which sulfide percolates upward removing oxygen from the overlying sediment.

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