Effect of fuel to air ratio on Mach 0.3 burner rig hot corrosion of ZrO2-Y2O3 thermal barrier coatings

A Mach 0.3 burner rig test program was conducted to determine how the fuel to air mass ratio affects the durability of ZrO2-Y2O3/Ni-16Cr-6Al-0.31Y thermal barrier coating systems in combustion products containing 5 ppm Na and 2 ppm V. As the fuel to air mass ratio was increased from 0.039 to 0.049, the durability of ZrO2-6Y2O3, ZrO2-8Y2O3 and ZrO2-12Y2O3 coatings decreased. ZrO2-8Y2O3 coatings were approximately 2X and 1.3X more durable than ZrO2-12Y2O3 and ZrO2-6Y2O3 coatings respectively at the fuel to air mass ratio of 0.039. The number of one hour cycles endured by ZrO2-8Y2O3 coatings varied from averages of 53 to 200 for the fuel to air mass ratios of 0.049 and 0.039, respectively. At the fuel to air mass ratio of 0.049, all ZrO2-Y2O3 coated specimens failed in 40 to 60 one hour cycle

Institutionalized Discrimination in the Legal System: A Socio-Historical Approach

Despite many of the social, political, and economic changes of the 1960s, discrimination is still prevalent in the United States. Increasingly, evidence of discrimination can be seen in our nation\u27s courts, institutions of higher education, in public policy decisions, and every social, political and economic institution. The question of how this can be in these days of ethnic and cultural diversity has aroused considerable interest among social scientists, as well as among the general public. One area that has been the target of considerable research is the criminal justice system. Wilbanks[1] has suggested that it is a myth that the criminal justice system is racist and discriminates against blacks and other minorities. This paper argues to the contrary. It is suggested that Wilbanks has inappropriately applied a microlevel analysis to a macrolevel phenomenon. Examining the historical-structural nature of the legal systems points to great disparities in the status quo of US jurisprudence

Surfaces for micrometeoroid impact crater detection

Surfaces for micrometeroid impact crater detectio

Corrosion resistant thermal barrier coating

A thermal barrier coating system for protecting metal surfaces at high temperature in normally corrosive environments is described. The thermal barrier coating system includes a metal alloy bond coating, the alloy containing nickel, cobalt, iron, or a combination of these metals. The system further includes a corrosion resistant thermal barrier oxide coating containing at least one alkaline earth silicate. The preferred oxides are calcium silicate, barium silicate, magnesium silicate, or combinations of these silicates

Characterizing Surface Deformation from 1981 to 2007 on Mount Baker Volcano, Washington

Surface deformation studies at active volcanoes are used to detect changes to magmatic source regions beneath the volcano. At Mount Baker, Washington, continued elevated gas (CO2 and H2S) and heat flux from fumaroles in Sherman Crater indicate the presence of a degassing magma reservoir. Campaign geographic positioning system surveys in 2006 and 2007 provide slope distance measurements of all 19 trilateration lines on Mount Baker. These data are compared with previous slope distance measurements acquired in 1981 and 1983 with electronic distance measurement. The results indicate that surface deformation has occurred on Mount Baker during the last quarter century. Slope distances have predominantly shortened around the edifice at rates of less than 2 mm/yr. The greatest slope length change detected (HDLY-RSVT) is -17 ± 4 ppm on the northern flank of the volcano. A nonlinear least-squares regression fits a uniform surface strain-rate model to the weighted slope change data. The strain model results indicate contractional strain accumulation on Mount Baker with an areal dilation rate of -420 ± 140 nanostrain/yr. The observed strain-rate is distinctly different, by at least an order of magnitude, than the expected regional secular strain-rate from tectonic sources. Elastic dislocation models are used to invert for the location, and strength of a point source at depth. The inversion uses a discrete grid search to find the global minimum of the residuals from a nonlinear least squares algorithm. The optimal model predicts a volume change of -11 x 106 m3, located 1500 meters east-northeast of the summit at a depth of 5.4 km (MSL). However, the global minimum in not well defined, resulting in a wide range of suitable source parameters. The model can account for much of the deformation detected, indicating that a spherical source model is appropriate, at least to a first order, for modeling physical changes to the magmatic or hydrothermal system at Mount Baker. These results suggest that the magmatic and hydrothermal system at Mount Baker has depressurized, likely from the combined result of cooling, mass loss, and/or densification, since 1981. This study also provides a new baseline for precise geodetic study of ongoing quiescent degassing at Mount Baker

Dietary Shifts Related to Water Availability and the Demographic Response to Changing Prey Abundance of Carnivores in the West Desert, Utah

The decrease in number and range of North American large carnivores, has often all owed smaller carnivores ( \u3c 15 kg) to fill the role of the top predator. This has favored some carnivores such as coyotes (Canis latrans), who have expanded their distribution. Other small carnivores such as kit foxes (Vulpes macrotis) have experienced a range shrinkage and their population status throughout the United States is a concern. Historically, western U.S. natural resource management agencies installed artificial water sources to assist desert wildlife, but some researchers believe the access to water allowed more coyotes to live in Utah’s West Desert. In the late-1980s, research proposed that without free drinking water, coyotes would have to triple their food consumption to survive. More recent coyote research has found no evidence to support these claims. We used data collected between 2010 and 2013 on the U.S. Army Dugway Proving Ground (DPG) in Utah’s West Desert to examine if the coyotes’ changed their diet when drinking water was removed and to determine how kit foxes respond to changing prey abundance. We examined coyote scats to see if they shifted towards eating more large-bodied prey (i.e., leporids such as jackrabbits and cottontails) in the areas void of drinking water. We found no evidence of a dietary shift towards larger prey to meet energy requirements in the areas where there was no available free water. Our results, in addition to previous DPG research, provide strong evidence that coyotes in the West Desert are desert-adapted carnivores and are not influenced by artificial water sources. The 4-year DPG dataset also allowed us to investigate if kit fox litter sizes and pup survival changed when prey abundance changed. We found no connection between kit fox litter size and rodent or leporid abundance. However, we found a 3-fold increase in kit fox pup survival in 2012 when rodent abundance nearly doubled. Diet analysis of kit fox scats showed four prey categories (rodent, insect, kangaroo rat, leporid) represented 78.5% occurrence of all prey items. We found that kit foxes changed their diet when kangaroo rat abundance changed. As prey resources have changed over the last 60 years, the DPG kit foxes have shown to be flexible in their diet by shifting away from their historical leporid use to now heavily relying on rodents. In addition to more research on kit foxes, we recommend that future studies also focus on their prey populations to help ensure the future of the West Desert kit fox

A Best-Evidence Synthesis of the Relationship of Multiple Intelligence Instructional Approaches and Student Achievement Indicators In Secondary School Classrooms

The purpose of this study was to synthesize the literature in order to assess and quantify (if possible) the relationship between MI instructional approaches and student achievement indicators in secondary school classrooms (grades 6-12). This study employed the best-evidence synthesis methodology devised by Robert Slavin. Criteria for study inclusio n included germaneness, minimization of bias, and validity. This study allows for several conclusions: (1) a very limited amount of research focusing on the relationship of MI instructional approaches and student achievement indicators in secondary school classrooms exists, (2) instances of MI instructional approaches vary widely in methodology and implementation but demonstrate a fairly consistent philosophical approach, and (3) the studies included in this research synthesis failed to prove causation in the relationship of MI instructional approaches and student achievement indicators in secondary school classrooms. However, substantial evidence exists showing that multiple intelligences theory contributes positively to student learning and development. Further research is needed to quantify the relationship between MI instructional approaches and academic achievement indicators in secondary classrooms

A Point Model of Aquifer Cleanup with a Distribution of First-Order Rate Parameters

Many try modeling groundwater contaminant transport to predict it. Is this possible with rate-limited processes, and under what conditions? On occasion, cleanups go slower than predicted (tailing) and hazardous concentrations reappear after cleanup is thought complete (rebound). Rate-limited transport is blamed by many. When immobile water is present, diffusion from varied sizes and shapes of immobile regions can cause varied rate limitations (due to varied diffusion path lengths). Although known, most modelers represent these varied rate-limiting processes with a single \u27representative\u27 rate-parameter. This can yield poor predictions for long-term experiments, and the parameter is generally time and pump-rate dependent. This model employs a distribution of first-order rate parameters to investigate the effects of using a single rate-parameter. Spatial effects are ignored by using volume-averaged concentrations (a point, well-mixed model) and dilutive pumping and rate-limited transport are modeled to isolate rate-limited transport for study. A three-parameter Gamma distribution defines the rate parameter continuum. A clean flow approximation is used extensively, and pulsed pumping is examined briefly. An effective time and pump-rate dependence is seen in the average rate. Long-term soil and contaminant transport characteristics along with uptake history or good experimentally-derived initial contaminant presence are concluded as necessary for accurate predictions

Evaluation of hot corrosion behavior of thermal barrier coatings

Calcium silicate and yttria stabilized zirconia/MCrAlY thermal barrier coating systems on air-cooled specimens were exposed to sodium plus vanadium doped Mach 0.3 combustion gases. Thermal barrier coating endurance was determined to be a strong inverse function of ceramic coating thickness. Coating system durability was increased through the use of higher Cr + Al NiCrAl and CoCrAlY bond coatings. Chemical and electron microprobe analyses supported the predictions of condensate compositions and the determination of their roles in causing spalling of the ceramic coatings