Design of North Texas Pc Users Group Ecommerce Interface and Online Membership System

The North Texas PC Users Group is a non-profit that is struggling with their existing membership process. This thesis explores the analysis of a new membership process and discusses the resulting new architecture and system design to implement it. The implementation of this new business process will reduce the time to produce the standard monthly reports and foster future membership retention efforts. The new design supports Ecommerce instant transactions, online availability of reports for the Board of Directors, and the access control of a member-only online site. The research for this project included an analysis of the cost, benefits, and features needed for online credit card transactions by a small non-profit organization. The presented architectural design supports an n-tiered distributed application, over an underlying relational database which will ensure the membership information is safe, accurate, and timely while supporting future performance, scalability, and reliability needs

Data Center Green Performance Measurement: State of the Art and Open Research Challenges

Data centers (DC/DCs) are indispensable elements of information systems. The increase in information technology service demand drives their worldwide grow in number, size and energy consumption. In the light of depleting raw natural resources and climate change induced by greenhouse gases (GHG) the environmental impacts of DCs have received particular attention. This paper reviews literature to highlight major issues that contribute to DCs ecologic sustainability, and explores the state of the art of green performance indicators (GPIs) to assess DCs environmental performance, in particular the energy, GHG and resource efficiency. Afterwards, the identified GPIs are classified and clustered to construct a green performance measurement system. Furthermore, the paper generates insights in relation to the recognition and application of proposed GPIs in practice through 13 questionnaires and two expert interviews. Thus, the paper provides academics and practitioners with the body of knowledge on DC green performance measurement, and moreover formulates open research challenges

A study of System Interface Sets (SIS) for the host, target and integration environments of the Space Station Program (SSP)

System interface sets (SIS) for large, complex, non-stop, distributed systems are examined. The SIS of the Space Station Program (SSP) was selected as the focus of this study because an appropriate virtual interface specification of the SIS is believed to have the most potential to free the project from four life cycle tyrannies which are rooted in a dependance on either a proprietary or particular instance of: operating systems, data management systems, communications systems, and instruction set architectures. The static perspective of the common Ada programming support environment interface set (CAIS) and the portable common execution environment (PCEE) activities are discussed. Also, the dynamic perspective of the PCEE is addressed

Simplified Homodyne Detection for FM Chirped Lidar

The investigation of global warming requires more sensitive altimeters to better map the global ice reserves. A homodyne detection scheme for FM chirped lidar is developed in which dechirping is performed in the optical domain, simplifying both the optical and the RF circuits compared to heterodyne detection. Experiments show that the receiver sensitivity approaches the quantum limit and surpasses the performance of direct and heterodyne detection. In addition, the required electrical bandwidth of the photodiode and receiver RF circuitry are both significantly reduced, facilitating the use of large area photodetector arrays. A field trial using a 5"-aperture diameter telescope and a 370-m target range verified the sensitivity estimation and demonstrates the feasibility of this technique. The problem of homodyne carrier fading is addressed by incorporating a phase diversity receiver using a 90-degree optical coupler. Finally, an outline of the future direction of research is given

Why the sustainable provision of low-carbon electricity needs hybrid markets

Deep decarbonization of energy systems poses considerable challenges to electricity markets and there is a growing consensus that an energy-only design based on short-term marginal cost pricing cannot deliver adequate levels of investment and long-term coordination across actors and sectors. Based on the instructive example of the evolution of European electricity market designs, we discuss several shortcomings of energy-only markets and illustrate how ad-hoc policies that intend to address them have limitations of their own, notably a lack of systemwide coordination. Second, we describe how the sheer scale and nature of deep decarbonization targets requiring massive investment in capital-intensive low-carbon technologies exacerbate these issues. Ambitious emission reduction targets thus require an evolution of market design towards hybrid regimes. Hybrid markets separate long-term investment decisions from short-term operations through a balanced and differentiated use of competitive and regulatory design elements to coordinate and de-risk investment. Finally, a historical analysis of the evolution of different electricity market designs shows how hybrid markets constitute contemporary forms of long-run marginal cost pricing that are appropriate for meeting deep decarbonization targets with reduced uncertainty and hence lower private and social costs

Finite Element Modal Formulation for Panel Flutter at Hypersonic Speeds and Elevated Temperatures

A finite element time domain modal formulation for analyzing flutter behavior of aircraft surface panels in hypersonic airflow has been developed and presented for the first time. Von Karman large deflection plate theory is used for description of the structural nonlinearity and third order piston theory is employed to account for the aerodynamic nonlinearity. The thermal loadings of uniformly distributed temperature and temperature gradients across the panel thickness are incorporated into the finite element formulation. By applying the modal reduction technique, the number of governing equations of motion is reduced dramatically so that the computational time of direct numerical integration is dropped significantly. All possible types of panel behavior, including flat, buckled but dynamically stable, limit cycle oscillation (LCO), periodic motion, and chaotic motion can be observed and analyzed. As examples of the applications of the proposed methodology, flutter responses of isotropic, specially orthotropic and laminated composite panels are investigated. Special emphasis is put on the boundary between LCO and chaos, as well as the routes to chaos. A systematic mode filtering procedure that helps mode selection without specific knowledge of the complex mode shapes is presented and illustrated. Influences of aerodynamic parameters, including aerodynamic damping and Mach number, on the panel flutter responses are studied. The importance of nonlinear aerodynamic terms is examined in detail. The supporting conditions and panel aspect ratio on the onset condition of chaos are also investigated as an illustration of optimization among different design options. Several mathematical tools, including the time history, phase plane plot, Poincaré map, and bifurcation diagram are employed in the chaos study. The largest Lyapunov exponent is also evaluated to assist in detection of chaos. It is found that at low or moderately high nondimensional dynamic pressures, the fluttering panel typically takes a period-doubling route to evolve into chaos, whereas at high nondimensional dynamic pressure, the route to chaos generally involves bursts of chaos and rejuvenations of periodic motions. Various bifurcation behaviors, such as the Hopf bifurcation, pitchfork bifurcation, and transcritical bifurcation, are observed. On the basis of the successful applications presented, the proposed finite element time domain modal formulation and the mode filtering procedure have proven to be an efficient and practical design tool for designers of hypersonic vehicle

Why the sustainable provision of low-carbon electricity needs hybrid markets

Deep decarbonization of energy systems poses considerable challenges to electricity markets and there is a growing consensus that an energy-only design based on short-term marginal cost pricing cannot deliver adequate levels of investment and long-term coordination across actors and sectors. Based on the instructive example of the evolution of European electricity market designs, we discuss several shortcomings of energy-only markets and illustrate how ad-hoc policies that intend to address them have limitations of their own, notably a lack of systemwide coordination. Second, we describe how the sheer scale and nature of deep decarbonization targets requiring massive investment in capital-intensive low-carbon technologies exacerbate these issues. Ambitious emission reduction targets thus require an evolution of market design towards hybrid regimes. Hybrid markets separate long-term investment decisions from short-term operations through a balanced and differentiated use of competitive and regulatory design elements to coordinate and de-risk investment. Finally, a historical analysis of the evolution of different electricity market designs shows how hybrid markets constitute contemporary forms of long-run marginal cost pricing that are appropriate for meeting deep decarbonization targets with reduced uncertainty and hence lower private and social costs

Optimization of layered battery cathode materials synthesized via spray pyrolysis

Rapid advancements of techniques for the synthesis of Li-ion battery materials are critically needed to address the requirement of a clean and efficient transportation sector. The current research serves this goal by developing an approach to producing layered cathode materials with superior electrochemical performance for electric vehicles (EVs). Current widespread application of EVs is primarily limited by their short range and their high price, which is primarily driven by the cost of the battery pack. The cost of the battery pack is driven by the cost of the cathode material that empowers it. Novel, high throughput and inexpensive synthesis methods delivering nanostructured materials are a key to meeting these requirements. The synthesis techniques need to be scalable, robust, and reproducible while producing high-density materials for lithium ion batteries. To this end we advance spray pyrolysis for the synthesis of the layered NMC composite materials, which are showing high promise as a cathode material. Spray pyrolysis produces high purity materials, and the limited number of process parameters allows for low cost and excellent control over product properties and outstanding batch-to-batch reproducibility. Layered Li-excess composite materials show nearly twice the capacity of commercial LiCoO2 cells. The materials are inexpensive, have improved safety characteristics and long cycle life. Yet, as recently demonstrated, the materials suffer from an inherent layered-spinel phase change. This leads to a voltage fade over extended cycling, and this shortcoming needs to be addressed before commercial implementation is feasible. In this work spherical-shape layered xLi2MnO3*(1-x)LiNi1/3Mn1/3Co1/3O2 composites were synthesized. The relationship between composition and material stability under different synthesis conditions (350 °C - 800°C reactor temperatures, 0.5 - 2.5 M concentration, 6.6 - 10.4 lpm flow rates) were explored. We found that from among the compositions corresponding to x = 0.3, 0.5 and 0.7, the composition for x = 0.3, or Li1.14Mn0.46Ni0.2Co0.2O2, provides improved stability and the least amount of voltage fade while displaying capacities around 190 mAhg-1 after 100 cycles at C/10 rate at room temperature. At the same time, for x = 0.5, or Li1.2Mn0.54Ni0.13Co0.13O2, the material delivers 205-210 mAhg-1 discharge capacities at C/3 rate at room temperature after 100 cycles, but displays more voltage fade over cycling. This work demonstrated that the major process parameters (flow rate, reactor synthesis temperature and concentration) can be accurately controlled and the synthesis method is robust. The reproducibility of the process was evaluated using charge and discharge tests and the standard deviation for cycling tests was 4 mAhg-1 at C/3 rate based on 4 batches produced under identical conditions on different dates. This indicates excellent batch-to-batch reproducibility. Post-synthesis annealing temperature optimization was performed for cobalt doped samples at 850 °C and 900 °C and we found that annealing for 900 °C for 2 hours improves the cycling stability of the samples. We evaluated the effect of lithium content between 3.3 wt% excess and 3.3 wt% deficiency and annealed the materials for 2, 5 and 20 hours at 900 °C. This helped develop a fundamental understanding between surface area and internal structural changes related to the Li2MnO3 structural component of the materials. Spray pyrolysis uniquely allows for the accurate control of stoichiometry and composition to trace contaminant level at these concentrations. Furthermore, through a collaborative research between Argonne National Laboratory, X-Tend Energy, LLC and Washington University in St. Louis a novel, highly scalable patent-pending slurry spray pyrolysis process was developed, which allows the production of battery materials with excellent electrochemical performance and provides a general platform for oxide materials at greater than 50 gh-1 scale. This unique process is the only known solution to the hollow sphere issue that has challenged spray pyrolysis synthesis for decades, namely producing particles greater than 2 μm size with a solid (non-hollow) but porous interior morphology. Tap densities greater than 1.0 gcm-3 are achieved at greater than 50 gh-1 scale as compared to 0.4-0.6 gcm-3 at 2 gh-1 scale. Li1.2Mn0.54Ni0.13Co0.13O2 produced by this novel process delivered ~205 mAhg-1 discharge capacity after 100 cycles at C/3 rate at room temperature, reproducing the electrochemical performance of the laboratory scale synthesis process and meeting or exceeding the performing of materials produced by co-precipitation. Voltage fade was addressed in the latter part of the work by varying the compositional ratio and using trace elemental doping. Results demonstrated for the first time that by selectively doping the xLi2MnO3*(1-x)LiNi1/3Mn1/3Co1/3O2 materials voltage fade can be reduced, as indicated by dQ/dV curves. The spray pyrolysis process for xLi2MnO3*(1-x)LiNi1/3Mn1/3Co1/3O2 materials, in particular for layered Li1.2Mn0.54Ni0.13Co0.13O2 displayed the highest capacity (c.a. 205-210 mAhg-1 after 100 cycles at C/3 rate at room temperature) among all cathode materials synthesized via spray pyrolysis to date