Things that ignore

I make landscape and figurative paintings and prints that explore the symbiosis between the sublime and the quotidian. My work is guided by a theory of the sublime that is rooted in divine indifference, the notion that the divine attracts what it initially repels and that absence is presence. Much of my imagery is pulled from a cross country archive of personal photographs and a no-brow collection of film stills. Drawing comparisons between these sources and the ongoing history of landscape, I denaturalize subjects through a painterly appropriation of cinematic sensibilities in order to destabilize a fixed gaze, foster a slow sense of pace and embed an ambivalent characterization of place. The transient figures, animals and apparitions are personified limbs of the natural and urban landscapes that they traverse, wrestling with false ideologies and wobbly sentiments of faith

Development of a Power Efficient, Restartable, Green Propellant Thruster for Small Spacecraft and Satellites

This paper details the development of an innovative green hybrid rocket propulsion system, applicable to small spacecraft. When fully developed this propulsion technology has the potential to act as a drop in replacement for propulsion system utilizing hazardous propellants such as hydrazine. Fuel grains are manufactured using a form of additive manufacturing known as Fused Deposition Modeling (FDM). Using FDM overcomes multiple technical issues frequently associated with hybrid propulsion systems. Issues include low-output-rate manufacturing, a lack of system restartability, and poor volumetric efficiency. FDM reduces development and production costs by supporting high production rates across a wide range of form factors. Using FDM, thermoplastic fuel grains can be fabricated with port shapes that enhance burn properties and increase volumetric efficiencies. Most significantly, because FDM-processing builds the specimen one layer at a time, most thermo-plastic materials fabricated via FDM possess unique electrical breakdown properties that greatly enhance system ignitability and restartabilty. When FDM-processed fuel materials are subjected to a high-voltage inductive charge, an electrical-arc develops along the layered material surface and Joule heating produces a small amount of pyrolized vapor. When the arc occurs simultaneously with the introduction of an oxidizing flow, the pryolized hydrocarbon vapor seeds combustion and produces immediate ignition along the entire length of the fuel material. Fuel regression rates are compared with analytical predictions to conclude this paper

High Regression Rate Hybrid Rocket Fuel Grains with Helical Port Structures

Hybrid Rockets are popular in the aerospace industry due to their storage safety, simplicity, and controllability during rocket motor burn. However, they produce fuel regression rates typically 25% lower than solid fuel motors of the same thrust level. These lowered regression rates produce unacceptably high oxidizer-to-fuel (O/F) ratios that produce a potential for motor instability, nozzle erosion, and reduced motor duty cycles. To achieve O/F ratios that produce acceptable combustion charactersitics, traditional cylindrical fuel ports are fabricated with very long length-to-diameter ratios to increase the total burning area. these high aspect ratios produce further reduced fuel regression rate and trust levels, poor volumetric efficiency, and a potential for lateral structural loading issues during high thrust burns. In place of traditional cylindrical fuel ports, it is proposed that by researching the effects of centrifugal flow patterns introduced by embedded helical fuel port structures, a significant increase in fuel regression rates can be observed. The benefits of increasing volumetric efficiencies by lengthening the internal flow path will also be observed. The mechanisms of this increased fuel regression rate are driven by enhancing surface skin friction and reducing the effect of boundary layer blowing to enhance convective heat transfer to the fuel surface. Preliminary results using additive manufacturing to fabricate hybrid rocket fuel grains from acrylonitrile-butadiene-styrene (ABS) with embedded helical fuel port structures have been obtained, with burn-rate amplifications up to 3.0x than that of cylindrical fuel ports

Solubility of Red Phosphorous in Lead

The determination of the solubility of red phosphorus in lead can be used to produce a plot of the solubility with respect to temperature and pressure. The plot is produced with experimental data, activity determination from present thermodynamic data, and compilation of the two sets of data into the semi-regular solution format. A lead-phosphorus solubility diagram is necessary to determine the amount phosphorus that will be absorbed by lead and will remain unreacted in a given process

Mechanical Properties Of Neat Cement Paste: Investigation Of Correlation To Degree Of Hydration And Water-To-Cement Ratios

The mechanical strength of cement paste is the property of the material that is most obviously required for structural use. The strength of mortar or concrete depends on the cohesion of the cement paste and its adhesion to the aggregate particles. Cement paste consists of two parts, cement and water. When water is added to cement, it reacts with the cement in what is known as the hydration process. The scope of this study is to determine the mechanical properties of hydrated cement paste with respect to the degree of hydration for different water-to-cement ratios, for developing a molecular macroscopic model for numerical simulations at the nano-scale. Hydration, compression, elastic modulus, flexure and direct tension tests were performed to complete this study. Vacuum-sealed dry curing was chosen for the specimens in this experiment. Results showed that with increased degree of hydration, there was an overall increase in the compressive strength. However, for the tensile strength, there was an overall decrease in both flexure and direct tensile strength

Likelihood Estimation for Block Cipher Keys

In this paper, we give a general framework for the analysis of block ciphers using the statistical technique of likelihood estimation. We show how various recent successful cryptanalyses of block ciphers can be regarded in this framework. By analysing the SAFER block cipher in this framework we expose a cryptographic weakness of that cipher

Conflicting Attitudes in Environmental Management and Brownfield Redevelopment

An enhanced attitudes methodology within the framework of the Graph Model for Conflict Resolution (GMCR) is developed and applied to a range of environmental disputes, including a sustainable development conflict, an international climate change negotiation and a selection of brownfield conflicts over a proposed transfer of ownership. GMCR and the attitudes framework are first defined and then applied to a possible Sino-American climate negotiation over reductions in greenhouse gas emissions. A formal relationship between the attitudes framework and relative preferences is defined and associated mathematical theorems, which relate the moves and solution concepts used in both types of analysis, are proven. Significant extensions of the attitudes methodology are devised in the thesis. The first, dominating attitudes is a methodology by which the importance of a decision maker’s (DM’s) attitudes can be used to evaluate the strength of a given state stability. The second, COalitions and ATtitudes (COAT), is an expansion of both the attitudes and coalitions frameworks which allows one to analyze the impact of attitudes within a collaborative decision making setting. Finally, the matrix form of attitudes, is a mathematical methodology which allows complicated solution concepts to be executed using matrix operations and thus make attitudes more adaptable to a coding environment. When applied to environmental management conflicts, these innovative expansions of the attitudes framework illustrate the importance of cooperation and diplomacy in environmental conflict resolution

Scanning Tunneling Microscopy of Electrically Driven Phase Transitions in a Charge Density Wave Material

The 1T polytype of the van der Waals material TaS2, has been studied extensively as a strongly correlated system. Exhibiting several different charge density wave (CDW) states, the phase diagram of 1T-TaS2 has been explored for close to fifty years, as the forces driving the formation of the charge modulation and determining the characteristics of each of the phases, have been elucidated. In recent years, interest in this system has concerned expanding the phase diagram, with the bulk equilibrium states being further probed and manipulated. While much of the research has focused on the low-temperature phase, where 1T-TaS2 has emerged as a test bed for Mott physics, as the material is thinned towards the 2D limit, its phase diagram shows significant deviations from that of the bulk system, even in the higher temperature range. Optoelectronic maps of ultrathin (< 10 nm thick) 1T-TaS2 have indicated the presence of non-equilibrium CDW phases within the hysteresis region of the nearly commensurate (NC) to commensurate (C) transition. The work in this thesis investigates the nature of these non-equilibrium phases, and in doing so, further elucidates the phase diagram of 1T-TaS2. We perform scanning tunneling microscopy (STM) on exfoliated ultrathin flakes of 1T-TaS2 within the NC-C hysteresis window. Imaging exfoliated flakes using STM poses certain difficulties. Specifically, STM is very sensitive to surface contamination and is ill-suited for locating a specific region of interest in a sample with micron scale dimensions. We address the challenges associated with performing STM on exfoliated materials, utilizing a simple device design that allows for the in situ measurement of both the electrical properties of an exfoliated flake and the topography of the flake. With such a device design, it is possible to correlate changes in electronic structure with changes in the bulk properties of the material. When imaging ultrathin 1T-TaS2 within the NC-C transition region, we find that rather than possessing distinct electronic order, the topography of the flake indicates the presence of intertwined, irregularly shaped NC-like and C-like domains. After applying lateral electrical signals to the sample, we image changes in the geometric arrangement of the different regions. The ability to measure the change in electronic structure with the application of a driving signal provides an invaluable perspective on the evolution of the CDW phases in the material at the nanoscale. Inhomogeneity similar to what we measure in ultrathin 1T-TaS2, has been seen in related strongly correlated systems, such as perovskite manganites and doped Mott insulators. Starting with a phase separation model to simulate the observed inhomogeneity, we incorporate ideas derived from percolation theory to explore the relationship between the electronic structure present in ultrathin 1T-TaS2 and its bulk resistivity. With this model, we are able to qualitatively reproduce many of the features observed when driving the inhomogeneous CDW state. These results highlight the importance of understanding the role of phase competition in determining the properties of strongly correlated systems