The kinetics of the oxidation of [Fe(CN)6]-4 by K[Co(HEDTA)NO2] was studied in order to get the mechanism and the activation parameters of the reaction. Using a freshly-made Na3PO4 solution as the reaction medium with a pH of 6.00 the ionic strength was maintained at 0.10 M and the buffer molarity was 0.001 M. The rate constant (kobs) of the reaction between [Fe(CN)6]-4 and K[Co(HEDTA)NO2] was determined at temperatures of 25.0°C, 27.5°C, 30.0°C, 35.0°, and 40.0°C. We explored this reaction by monitoring the evolution of ferricyanide, [Fe(CN)6]-3, spectroscopically for which ε420 = 1023 cm-1 M-1 by recording the absorbance as a function of time at 420 nm wavelength. The data were plotted and results analyzed to give activation parameters, energy of activation (Ea), entropy of activation (ΔS‡), and enthalpy of activation (ΔH‡) for the two reacting complexes under the specified reaction conditions. Based on previous results, an outer-sphere electron-transfer pathway and a first order rate of reaction for each of the reacting species 1 have been proposed.

No description available.

No description available.

Black carbon, a proxy for woodsmoke was measured indoors and outdoors for an occupied residence in Cambria, CA during the winter months of 2009. The purpose was to investigate the infiltration parameters: air exchange rate, deposition rate, and penetration factor. The second part of this study investigated the light absorption properties of organic carbon from residential wood combustion, the dominant fraction of woodsmoke. To assess woodsmoke variation, a study conducted parallel to the one presented in this thesis (Ward, 2009), a grid array of personal emission monitors (PEMS) and aethalometers were placed in a small area, approximately one square kilometer, within a community in Cambria, California between the months of November 2008 and March 2009. In this study, PEMS were used to collect particles on filters, which were analyzed for tracers for woodsmoke, including levoglucosan, elemental carbon, and organic carbon. Aethalometers measured black carbon, an indicator of carbon combustion. Additional PEMS and aethalometers were placed inside one residential home to better understand infiltration of woodsmoke. To model the infiltration of woodsmoke, the Lawrence Berkeley National Laboratory Air Infiltration Model was used. The home of interest was chosen such that indoor sources of particulate matter (PM) were minimal. This insures that all PM measured indoors was from outdoor sources, namely household chimneys. While indoor sources such as indoor fires and resuspension of particles were of concern, homes were chosen to minimize these sources. To investigate the infiltration parameters, four different solution techniques were used. Two of the solution techniques used SOLVER, a Microsoft Excel program, to minimize the sum of squared differences between calculated indoor concentrations and measured indoor concentrations, with all three parameters (air exchange rate, penetration, and deposition) as independent variables. The other two solution techniques used the Air Exchange Rate (AER) model from Lawrence Berkeley National Laboratory (LBNL) (Sherman & Grimsrud, 1980) and then used SOLVER to calculate deposition rate and penetration factor. Solution techniques 1 and 3, which used SOLVER to find all three parameters, had average penetration factors of 0.94 and 0.97 respectively, while solution techniques 2 and 4, which used the LBNL AER model had average penetration factors of 0.85 and 0.78 respectively. The deposition rates for solution techniques 1,2,3, and 4 were 0.10, 0.07, 0.08, and 0.04 hr-1 respectively. The air exchange rates varied throughout the study and ranged from 0.1 to 0.7 hr-1. The average indoor/outdoor ratio was also found to be 0.75. The aerosols derived from the study samples were found to have light absorption properties that were heavily spectrally dependent, which is consistent with expectations for wood combustion aerosols. Conversely, traffic derived aerosols are not found to be heavily spectrally dependent and follow the power law relationship of λ-1 whereas our samples followed λ-1.7 across all wavelengths and λ-2.25 for wavelengths less than 600 nm. The reason for the difference in spectral dependence is the presence of light absorbing organic carbon in wood smoke that is not found in diesel aerosols. The optical absorbances were also calculated for our samples and average values were found to be 3 and 1 m2/g for 370 and 450 nm wavelengths respectively.

A promising feedstock for biofuels is microalgae. The most economical means of cultivating microalgae is via open raceway ponds. However, a large gap in economic feasibility exists between algae-based biofuels and traditional petroleum fuels. Recent research at Utah State University has focused on increasing biomass growth by implementing Delta Wings (DWs). DWs are placed facing the incoming flow, with a 40 degree angle of attack to create large vortices which travel downstream. The trailing vortices increase vertical mixing, which in turn increases algal growth. Past researchers at USU quantified vertical mixing with new metrics, optimized various raceway operating conditions, and established a positive correlation between the newly defined metrics and algal growth. Research was performed with the aid of a small-scale clear acrylic raceway. Both stereo particle image velocimetry (SPIV) and acoustic Doppler velocimetry (ADV) were used to estimate the recently defined mixing metric: the vertical mixing index (VMI). The focus of this work is to ascertain additional preferred operating conditions, in particular those unique to large scale raceways, with the aid of a computational fluid dynamics (CFD) model validated by experimental data. Three case studies are presented herein, which analyze the DW vertical position (VP), array spacing ratio (ASR), and the projected height to depth ratio (PHDR). The criteria for these studies are the VMI and power consumption. While it was previously assumed that vertically centering the DW centroid was optimal, the first case study revealed the ideal VP to be far lower. The lowest possible VP allows the trailing vortices to travel further downstream, resulting in increased vertical mixing. The second case study entails modeling complete arrays of DWs with various spacing. This model was the first to account for an increase in the number of allowable DWs with a decrease in array spacing. The ASR study revealed the ideal array spacing to be approximately half a DW, as opposed to the initial estimate of a full DW. The third case study confirmed the largest allowable DW to be superior.

Clinical depression is the most frequently reported mental health problem for adolescents. Previously studied psychological treatment approaches for adolescent depression have recently been combined and packaged into a comprehensive psychoeducational intervention titled the Adolescent Coping With Depression Course (ACWDC). This study investigated whether treatment of clinically depressed adolescents using the ACWDC resulted in significant emotional, behavioral, and/or academic performance changes as reported by the adolescent, and observed by the parents and teachers. Nineteen clinically depressed adolescents were identified by screening 876 students in a local high school, using a multistage screening procedure. All selected subjects met the DSM III-R criteria of major depression or dysthymia. Identified subjects were randomly assigned to either a treatment or a waitlist-control condition. Subjects in the treatment condition received treatment while subjects in the waitlist-control condition received no treatment until after the completion of the study (eight weeks later). Treatment consisted of participation in the ACWDC, conducted in 12 two-hour teaching sessions held over an eight-week period after school. Outcome measures included a variety of self-report, teacher, and parent rating scales. A pretest-posttest randomized experimental design was utilized to examine treatment effects. At post-testing, subjects receiving treatment reported significantly greater decreases in depression and problem behaviors than subjects not receiving treatment. However, at post-testing there were no significant differences between treatment conditions on parent- and teacher-observed problem behaviors, or teacher-reported academic performance changes. Based on the results of this study and previous studies, participation by clinically depressed adolescents in the ACWDC does result in significant self-reported decreases in depression and problem behaviors. However, contrary to expectations, these self-reported changes have not been consistently observed by parents or teachers in reductions of problem behaviors at home or school, nor in significant teacher-observed academic improvement at school.

A major issue facing nuclear power stations is how to effectively deal with radioactive waste. This waste, as it comes from a reactor, is emitting large quantities of ionizing radiation which is usually confined. Another form of radioactive wastes is the mill tailings from uranium processing plants. These tailings are sites characterized by low-level chronic radiation. The mill tailings of the Vitro Chemical Plant, in Salt Lake City, Utah, have been a point of radionuclide concentration and environmental contamination for 20 years. These tailings may adversely affect both surrounding ecosystems and any biological systems seeking to become established on the site. To test the potential hazard of this site to the succession of plant species I examined the interphase chromosome volume and relative amounts of DNA per chromosome from plants growing on this site and those on a control site. These nuclear parameters indicate the relative radio-sensitivity of a species and would demonstrate the total effectiveness of the low-level chronic radiation in altering plant succession. The radiosensitive plant Tradescantia clone 02 was also grown in five soil samples from the mill tailings which represented a progressive increase in radioactivity. The purpose was to determine how effective these radiation levels are in altering reproductive integrity, fecundity, and somatic mutation rates in radiosensitive plant species. There was a difference in species composition between plant communities growing on the mill tailings as compared to the controls as determined by coefficient of community. However, there was no difference in interphase chromosome volume or relative amounts of DNA per chromosome between plants growing on these two sites. The difference in species composition is attributed to the length of time each site has been undergoing succession, with the control site in a more advanced stage. Tradescantia grown in soil with a radiation dose greater than 0.10 mR/hr had significantly reduced reproductive integrity and fecundity, as measured by the number of stunted hairs on a stamen and poll en viability, and increased numbers of somatic mutations. Based on these data the radioactive mill tailings from the Vitro Chemical Plant have the potential to alter plant successional patterns due to their detrimental effect on any species that is relatively radiosensitive.

Massive shales and fractures are the main cause of seismic anisotropy in the upper-most part of the crust, caused either by sedimentary or tectonic processes. Neglecting the effect of seismic anisotropy in seismic processing algorithms may incorrectly image the seismic reflectors. This will also influence the quantitative amplitude analysis such as the acoustic or elastic impedance inversion and amplitude versus offsets analysis. Therefore it is important to obtain anisotropy parameters from seismic data. Conventional layer stripping inversion schemes and reflector based reflectivity inversion methods are solely dependent upon a specific reflector, without considering the effect of the other layers. This, on one hand, does not take the effect of transmission in reflectivity inversion into the account, and on the other hand, ignores the information from the waves travelling toward the lower layers. I provide a framework to integrate the information for each specific layer from all the rays which have travelled across this layer. To estimate anisotropy parameters I have implemented unconstrained minimization algorithms such as nonlinear conjugate gradients and variable metric methods, I also provide a nonlinear least square method, based on the Levenberg-Marquardt algorithm. In a stack of horizontal transversely isotropic layers with vertical axis of symmetry, where the layer properties are laterally invariant, we provide two different inversion schemes; traveltime and waveform inversion. / Both inversion schemes utilize compressional and joint compressional and converted shear waves. A new exact traveltime equation has been formulated for a dipping transversely isotropic system of layers. These traveltimes are also parametrized by the ray parameters for each ray element. I use the Newton method of minimization to estimate the ray parameter using a random prior model from a uniform distribution. Numerical results show that with the assumption of weak anisotropy, Thomsen’s anisotropy parameters can be estimated with a high accuracy. The inversion algorithms have been implemented as a software package in a C++ object oriented environment.

This thesis is concerned with the characterisation of the parameters governing the tension-softening relations of the cohesive crack model. Parameter identification is an important area in fracture mechanics as it enables the use of a fracture model for the simulation of fracture processes in structures. Research, however, has shown that such a task is not trivial and continues to pose challenging problems to experimentalists and analysts alike. This dissertation presents general and efficient indirect methods for the characterisation of mode I fracture parameters defining the cohesive crack model. The identification problem is formulated as a special type of inverse problem. The formulation is in the form of a constrained optimisation problem known as a mathematical program with equilibrium constraints characterised, in the present instance, by complementarity conditions involving the orthogonality of two-sign constrained vectors. The solution of such a mathematical program is computationally challenging as it is disjunctive and nonconvex by nature. A number of nonlinear programming based approaches are proposed, after appropriate reformulation of the mathematical program as an equivalent nonlinear programming problem. Actual experimental data are used to validate and determine the most suitable algorithm for parameter identification. It was found that the smoothing-based method is by far superior than other schemes. As the problem is nonconvex and the nonlinear program can only guarantee a local or stationary point, global optimisation procedures are introduced in order to verify the accuracy of the solutions obtained by the algorithm. Two evolutionary search methods capable of finding the global optimum are implemented for parameter identification. The results generated by the evolutionary search techniques confirm the reliability of the solutions identified by the best nonlinear programming algorithm. All computations carried out in the thesis suggest the suitability and robustness of the selected algorithm for parameter identification.

<p>The main idea of our work is the calibration parameters for the Heston stochastic volatility model. We make this procedure by using the OMXS30 index from the NASDAQ OMX Nordic Exchange Market. We separate our data into the stable period and high-volatility period on this Nordic Market. Deviation detection problem are solved using the Bayesian analysis of change-points. We estimate parameters of the Heston model for each of periods and make some conclusions.</p>