No description available.

Small molecule Zn(II) complexes containing N- and S- donor environments may serve as appropriate models for mimicking Zn protein sites, and thus, their reactions with heavy metal ions such as Pt(II) and W(0) may provide insight into possible adduct formation and zinc displacement. To study such possible interactions between zinc finger proteins and platinum-bound DNA, the ZnN2S2 dimeric complex, N,N?-bis(2- mercaptoethyl)-1,4-diazacycloheptane zinc (II), [Zn-1?]2, has been examined for Znbound thiolate reactivity in the presence of Pt(II) nitrogen ? rich compounds. The reactions yielded Zn/Pt di- and tri- nuclear thiolate-bridged adducts and metalexchanged products, which were initially observed via ESI-mass spectrometry (ESI-MS) analysis of reaction solutions, and ultimately verified by comparison to the ESI-MS analysis, 195Pt NMR spectroscopy, and X-ray crystallography of directly synthesized complexes. The isolation of Zn-(?-SR)-Pt-bridged [(Zn(bme-dach)Cl)(Pt(dien))]Cl adduct from these studies is, to our knowledge, the first Zn-Pt bimetallic thiolatebridged model demonstrating the interaction between Zn-bound thiolates and Pt(II). Additional derivatives involving Pd(II) and Au(III) have been explored to parallel the experiments executed with Pt(II). The [Zn-1?]2 was then modified by cleavage with Na+[ICH2CO2]- to produce (N- (3-Thiabutyl)-N?-(3-thiapentaneoate)-1,4-diazacycloheptane) zinc(II), Zn-1?-Ac or ZnN2SS?O, and 1,4-diazacycloheptane-1,4-diylbis(3-thiapentanoato) zinc(II), Zn-1?-Ac2 or ZnN2S?2O2, monomeric complexes (where S = thiolate, S? = thioether). The [Zn-1?]2 di- and Zn-1?-Ac mono-thiolato complexes demonstrated reactivity towards labile-ligand tungsten carbonyl species, (THF)W(CO)5 and (pip)2W(CO)4, to yield, respectively, the [(Zn-1?-Cl)W(CO)4]- complex and the [(Zn-1?-Ac)W(CO)5]x coordination polymer. With the aid of CO ligands for IR spectral monitoring, the products were isolated and characterized spectroscopically, as well as by X-ray diffraction and elemental analysis. To examine the potential for zinc complexes (or zinc-templated ligands) to possibly serve as a toxic metal remediation agents, Zn-1?-Ac and Zn-1?-Ac2 were reacted with Ni(BF4)2. The formation of Zn/Ni exchanged products confirmed the capability of ?free? Ni(II) to displace Zn(II) within the N-, S-, and O- chelate environment. The Zn/Ni exchanged complexes were analyzed by ESI-MS, UV-visible spectroscopy, IR spectroscopy of the acetate regions, and X-ray crystallography. They serve as foundation molecules for more noxious metal exchange / zinc displacement products.

Performance-based engineering (PBE) requires advances in hazard characterization, structural modeling, and nonlinear analysis techniques to fully and efficiently develop the fragility expressions and other tools forming the basis for risk-based design procedures. This research examined and extended the state-of-the-art in hazard characterization (wind and surge) and risk-based design procedures (seismic). State-of-the-art hurricane models (including wind field, tracking and decay models) and event-based simulation techniques were used to characterize the hurricane wind hazard along the Texas coast. A total of 10,000 years of synthetic hurricane wind speed records were generated for each zip-code in Texas and were used to statistically characterize the N-year maximum hurricane wind speed distribution for each zip-code location and develop design non-exceedance probability contours for both coastal and inland areas. Actual recorded wind and surge data, the hurricane wind field model, hurricane size parameters, and a measure of storm kinetic energy were used to develop wind-surge and wind-surge-energy models, which can be used to characterize the wind-surge hazard at a level of accuracy suitable for PBE applications. These models provide a powerful tool to quickly and inexpensively estimate surge depths at coastal locations in advance of a hurricane landfall. They also were used to create surge hazard maps that provide storm surge height non-exceedance probability contours for the Texas coast. The simulation tools, wind field models, and statistical analyses, make it possible to characterize the risk-consistent hurricane events considering both hurricane intensity and size. The proposed methodology for event-based hurricane hazard characterization, when coupled with a hurricane damage model, can also be used for regional loss estimation and other spatial impact analyses. In considering seismic hazard, a risk-consistent framework for displacement-based seismic design of engineered multistory woodframe structures was developed. Specifically, a database of probability-based scale factors which can be used in a direct displacement design (DDD) procedure for woodframe buildings was created using nonlinear time-history analyses with suitably scaled ground motions records. The resulting DDD procedure results in more risk-consistent designs and therefore advances the state-of-the-art in displacement-based seismic design of woodframe structures.

In geothermal reservoirs and unconventional gas reservoirs with very low matrix permeability, fractures are the main routes of fluid flow and heat transport, so the fracture permeability change is important. In fact, reservoir development under this circumstance relies on generation and stimulation of a fracture network. This thesis presents numerical simulation of the response of a fractured rock to injection and extraction considering the role of poro-thermoelasticity and joint deformation. Fluid flow and heat transport in the fracture are treated using a finite difference method while the fracture and rock matrix deformation are determined using the displacement discontinuity method (DDM). The fractures response to fluid injection and extraction is affected both by the induced stresses as well as by the initial far-field stress. The latter is accounted for using the non-equilibrium condition, i.e., relaxing the assumption that the rock joints are in equilibrium with the in-situ stress state. The fully coupled DDM simulation has been used to carry out several case studies to model the fracture response under different injection/extractions, in-situ stresses, joint geometries and properties, for both equilibrium and non-equilibrium conditions. The following observations are made: i) Fluid injection increases the pressure causing the joint to open. For non-isothermal injection, cooling increases the fracture aperture drastically by inducing tensile stresses. Higher fracture aperture means higher conductivity. ii) In a single fracture under constant anisotropic in-situ stress (non-equilibrium condition), permanent shear slip is encountered on all fracture segments when the shear strength is overcome by shear stress in response to fluid injection. With cooling operation, the fracture segments in the vicinity of the injection point are opened due to cooling-induced tensile stress and injection pressure, and all the fracture segments experience slip. iii) Fluid pressure in fractures increases in response to compression. The fluid compressibility and joint stiffness play a role. iv) When there are injection and extraction in fractured reservoirs, the cooler fluid flows through the fracture channels from the injection point to extraction well extracting heat from the warmer reservoir matrix. As the matrix cools, the resulting thermal stress increases the fracture apertures and thus increases the fracture conductivity. v) Injection decreases the amount of effective stress due to pressure increase in fracture and matrix near a well. In contrast, extraction increases the amount of effective stress due to pressure drop in fracture and matrix.

The commercial buildings sector in the United States used 18 percent (17.93 Quads) of the U.S. primary energy in 2006. Office buildings are the largest single energy consumption category in the commercial buildings sector of the United States with annual energy consumption around 1.1 Quads. Traditional approaches used in commercial building designs are not adequate to save energy in both depth and scale. One of the most effective ways to reduce energy consumption is to improve energy performance of HVAC systems. High-performance HVAC systems and components, as well as application of renewable energy sources, were surveyed for buildings in hot and humid climates. An analysis of performance and energy saving potential estimation for selected HVAC systems in hot and humid climates was developed based on energy consumption simulation models in DOE-2.1E. A calibrated energy consumption model of an existing office building located in the hot and humid climate conditions of Texas was developed. Based on this model, the energy saving potential of the building was estimated. In addition, energy consumption simulation models were developed for a new office building, including simulation of energy saving measures that could be achieved with further improvements of HVAC system above the energy conservation codes requirements. The theoretical minimum energy consumption level for the same office building was estimated for the purpose of evaluating the whole building energy efficiency level. The theoretical minimum energy consumption model of the office building was designed to provide the same level of comfort and services to the building occupants as provided in the actual building simulation model. Finally, the energy efficiency of the building that satisfies valid energy conservation codes and the building with an improved HVAC system was estimated based on theoretically minimum energy consumption level. The analysis provided herein can be used for new building practitioners and existing building owners to evaluate energy reduction potential and the performance of innovative technologies such as dedicated outdoor air system, displacement ventilation, improved cooling system efficiency, air source heat pumps and natural gas heat pumps.

The aim of this study is to model three dimensional surface crack problems in fillet welds. It is assumed that weld material has the same material properties with the sheet metals. The surface crack is considered to occur at two regions / one at the weld root and the other at the weld toe. The surface crack is assumed to have a semi &ndash / elliptical crack front profile. The surface crack problem is analyzed under mechanical loading and the models are built up by three dimensional finite elements. Around the crack front, strain singularity is taken into account by using degenerated 20 &ndash / node quarter &ndash / point solid elements. The main results of this work are the stress intensity factors around the crack front for the test specimen model subjected to axial and bending loads.

The main objective of this study is to model and analyze a three dimensional inclined semi-elliptic surface crack in a Functionally Graded Material (FGM) coating bonded to a homogeneous substrate with a bond coat. The parametric analyses on FGMs are based upon zirconia-yttria (ZrO2-8wt%-Y2O3) FGM coating bonded to a substrate made of a nickel-based superalloy. It is assumed that there is a nickel-chromium&amp / #8211 / aluminum&amp / #8211 / zirconium (NiCrAlY) bond coat between the FGM coating and substrate. Metal-rich, linear variation, ceramic-rich and homogeneous ceramic FGM coating types are considered in the analyses. The inclined semi-elliptic surface crack problem in the FGM coating-bond coat-substrate system is analyzed under transient thermal loading. This problem is modeled and analyzed by utilizing three dimensional finite elements. Strain singularity around the crack front is simulated using collapsed 20 &amp / #8211 / node quarter &amp / #8211 / point brick elements. Three &amp / #8211 / dimensional displacement correlation technique is utilized to extract the mixed mode stress intensity factors around the crack front for different inclination angles of the semi-elliptic surface crack. The energy release rates around the crack front are also calculated by using the evaluated mixed mode stress intensity factors. The results obtained in this study are the peak values of mixed mode stress intensity factors and energy release rates around the crack front for various inclination angles of the semi-elliptic surface crack embedded in the FGM coating of the composite structure subjected to transient thermal loading.

This thesis is concerned with modeling geometric patterns. Specifically, a clear and practical definition for regular patterns is proposed. Based on this definition, this thesis proposes the following modeling setting to describe the semantic transfer of a model between various forms of pattern regularity: (1) recognition or identification of patterns in digital models of 3D assemblies and scenes, (2) pattern regularization, (3) pattern modification and editing by varying the repetition parameters, and (4) establishing exceptions (designed irregularities) in regular patterns. In line with this setting, this thesis describes a representation and approach for designing and editing hierarchical assemblies based on grouped, nested, and recursively nested patterns. Based on this representation, this thesis presents the OCTOR approach for specifying, recording, and producing exceptions in regular patterns. To support editing of free-form shape patterns on surfaces, this thesis also presents the imprint-mapping approach which can be used to identify, extract, process, and apply relief features on surfaces. Pattern regularization, modification, and exceptions are addressed for the case of relief features on surfaces.

Although the study of the interaction of acoustic and elastic waves with periodic surfaces and structures has a rich history dating back to Lord Rayleigh, it has recently been attracting new research efforts due to its value in the study of phononic crystals and in methods for ultrasonic non-destructive evaluation (NDE). The objective of the research described in this thesis is to provide new numerical and experimental tools capable of capturing important features that occur due to the diffraction of ultrasound on periodic solid surfaces. This thesis is divided into four main parts. First, the Rayleigh-Fourier (R-F) method will be used to simulate diffracted fields generated by structures containing multiple periodic surfaces and/or multiple solid layers. The second part of this thesis examines diffraction effects and compares ultrasonic NDE techniques for surfaces with imperfect periodicities. The third portion of this thesis focuses on one unusual phenomenon that has been observed on periodic surfaces, namely the lateral backward displacement of a bounded ultrasonic beam along the surface. This effect is currently understood to occur due to backward propagating surface waves that result from diffraction and mode conversion on the surface. The fourth and final part of this thesis describes the diffraction of bulk ultrasonic waves that can occur on the surfaces of phononic crystals.

We study anomalous diffusion on fractals with a static external field applied. We utilise the master equation to calculate particle distributions and from that important quantities as for example the mean square displacement <r^2(t)>. Applying different bias amplitudes on several regular Sierpinski carpets we obtain maximal drift velocities for weak field strengths. According to <r^2(t)>~t^(2/d_w), we determine random walk dimensions of d_w<2 for applied external fields. These d_w corresponds to superdiffusion, although diffusion is hindered by the structure of the carpet, containing dangling ends. This seems to result from two competing effects arising within an external field. Though the particles prefer to move along the biased direction, some particles get trapped by dangling ends. To escape from there they have to move against the field direction. Due to the by the bias accelerated particles and the trapped ones the probability distribution gets wider and thus d_w<2. / In dieser Arbeit untersuchen wir anomale Diffusion auf Fraktalen unter Einwirkung eines statisches äußeres Feldes. Wir benutzen die Mastergleichung, um die Wahrscheinlichkeitsverteilung der Teilchen zu berechnen, um daraus wichtige Größen wie das mittlere Abstandsquadrat <r^2(t)> zu bestimmen. Wir wenden unterschiedliche Feldstärken bei verschiedenen regelmäßigen Sierpinski-Teppichen an und erhalten maximale Driftgeschwindigkeiten für schwache Feldstärken. Über <r^2(t)>~t^{2/d_w} bestimmen wir die Random-Walk-Dimension d_w als d_w<2. Dieser Wert für d_w entspricht der Superdiffusion, obwohl der Diffusionsprozess durch Strukturen des Teppichs, wie Sackgassen, behindert wird. Es schient, dass dies das Ergebnis zweier konkurrierender Effekte ist, die durch das Anlegen eines äußeren Feldes entstehen. Einerseits bewegen sich die Teilchen bevorzugt entlang der Feldrichtung. Andererseits gelangen einige Teilchen in Sackgassen. Um die Sackgassen, die in Feldrichtung liegen, zu verlassen, müssen sich die Teilchen entgegen der Feldrichtung bewegen. Somit sind die Teilchen eine gewisse Zeit in der Sackgasse gefangen. Infolge der durch das äußere Feld beschleunigten und der gefangenen Teilchen, verbreitert sich die Wahrscheinlichkeitsverteilung der Teilchen und somit ist d_w<2.