Correlation of ground tests and analyses of a dynamically scaled Space Station model configuration

Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined

Untangling the Myth of the Model Minority

The model minority stereotype depicts Asian Americans as a group that has succeeded in America and overcome discrimination through its hard work, intelligence, and emphasis on education and achievement - a modern-day confirmation of the American Dream. A large body of work by Asian critical scholars condemns this image and charges that it conceals more sinister beliefs about Asian Americans and other racial minorities in America. Is this critique correct? Does the model minority stereotype really mask hostility toward Asian Americans or breed contempt for other minorities? This article presents the results of an empirical study into the model minority stereotype. Using 1990, 1994, and 2000 General Social Survey data (including some of the very data used by critical scholars to establish the existence of this stereotype), we confirm claims that some non-Hispanic white Americans think that Asian Americans as a group are more intelligent, harder working, and richer than other minorities and that some think Asian Americans are more intelligent and harder working than whites. But we also discovered that these ideas are not usually linked with negative views of Asian Americans (or of other minorities, for that matter). Indeed, we found weak support for the contrary position - that those who rate Asian Americans higher than other minorities, or particularly higher than whites, are more likely to hold other positive views about Asian Americans, immigration, African Americans, and government programs supporting these groups. Our study nonetheless confirms the scholarly suspicions in one crucial respect: non-Hispanic whites who have positive views of Asian Americans are less likely to think that Asian Americans are discriminated against in both jobs and housing, thus tending to support the claims of some Asian critical scholars that positive stereotypes about Asian Americans tend to be associated with a failure to recognize continuing discrimination. In these data, however, this complacency by whites about prejudice against Asians does not translate into hostility toward government programs to alleviate the problems of Asian or African Americans

Wavelet analysis of atmospheric turbulence over a coral reef flat

The world’s tropical coral reefs are at risk of severe bleaching episodes and species decline in response to global climate variability. The ecological and economic value of reef ecosystems is enormous, yet very little is known of the physical interactions that take place at the coral–ocean–atmosphere interfaces. This paper introduces and validates a novel technique for the acquisition of surface energy balance measurements over Heron Reef, part of the Capricorn Bunker Group of the southern Great Barrier Reef, Australia. Measurements of surface energy and radiation exchanges were made using a Campbell Scientific eddy covariance (EC) measurement system mounted on a floating pontoon anchored to the reef flat. A Nortek Vector velocimeter was positioned next to the pontoon to record wave motion. Wavelet analysis techniques were used to decompose the turbulent exchange of sensible heat measured by the EC unit and to compare vertical velocity measurements with wave-induced motion recorded by the velocimeter. The results indicate that although the EC system and the velocimeter share intermittent periods of high common power in their respective wavelet variance spectra, these regions are not coherent and differ in strength by more than an order of magnitude. It was concluded that over a standard averaging period of 30 min the wave-induced motion of the pontoon would not significantly interfere with the acquisition and calculation of turbulent fluxes of sensible and latent heat, thereby confirming the robustness of this method of obtaining surface energy balance measurements over coral reefs

A Preliminary Investigation Of Three Advanced Wind Energy Systems For Residential And Farm Applications

This report is primarily concerned with an analysis of advanced wind driven energy systems. Three such systems, the Improved Wind Furnace System and the Wind Driven Total Energy Systems, Types I and II, for the supply of energy to electrical, space heating and domestic hot water loads are considered for new England residential and farm applications. These systems are studied with the aid of an interactive digital computer simulation (WDTEST) and an economics program (WSDECO). Although the programs incorporate some idealizations, they represent a necessary preliminary investigation of the total system and its components. The computer models are designed to be general enough to allow for wide variations of loads, component sizes, working fluids and energy costs, but specific enough to approach an optimum design point based on maximum energy efficiency or minimum total system costs.Results indicate that the Wind Driven Total Energy System, Type II model requires the least amount of auxiliary energy input to the system for all three residential and farm settings considered. However, it was found that the higher capital costs of the Wind Driver Total Energy System, Type II, did not justify its use when compared to the less energy efficient but also less expensive Improved Wind Furnace System. All systems studied though, if mass produced, were found to be less expensive annually than the conventional electric, oil and gas energy supply systems, provided that the capital costs are amortized over a twenty year period

U.S. AND PRC STRATEGIC COMPETITION: CYBER AND RISK AVERSION

The People’s Republic of China (PRC) altered its calculations from the aftermath of the 1990 Persian Gulf war and placed emphasis on the importance of technology and information. The PRC created the Strategic Support Force (SSF), which became operational in 2015, and includes space, cyber, and electronic warfare capabilities under one command. Meanwhile, the U.S. has wrapped itself in structural and cultural limitations, which hinder operational tempo. This thesis examined how the Department of Defense can adjust its positions on Cyber Titles, authorities, permissions, and risk aversion in leadership to maintain a competitive edge against the threat of the PRC’s SSF in the cyber domain. This thesis used system dynamics to model the economies of both the U.S. and the PRC into cyber capabilities, which resulted in an understanding that allocating additional money alone will not solve the core issue. Understanding the limitations of cultural biases, and using decision-making tools such as prospect theory, leaders can make more effective decisions. Through proper education of staff officers about cyber capabilities and their effects, integration of cyber operations at combat training centers, and pushing permissions and rules of engagements down to Task Force Commanders, the U.S. can overcome the structural and cultural obstacles.Major, United States ArmyMajor, United States Marine CorpsApproved for public release. Distribution is unlimited

The effect of a traditional and a stick gang-line on the body position of working sled dogs

This study aimed to investigate the effect of two different gang-lines on the pulling angle of sled dogs. It was hypothesised that dogs would run with a straighter angle of pull (in relation to the main-line) in stick gang-lines (STICK) than they would do in traditional gang-lines (TRAD). Eight sled dogs, divided into two teams, ran a 3.1 km trail twice in both types of gang-lines, pulling a quadbike on dry ground. Each dog remained in its team in the same position (side of gang line, and forward or back in the line) for both runs, using both types of lines in randomised order between the runs. Markers were placed on the dogs and on the main lines, and the runs were recorded by a video camera. The dogs' angle of pull measured from the video recordings was compared between the two conditions. Thirteen positional measurements for each dog during each run were taken. The dogs were used to running in TRAD and were not acclimatised to STICK. Data was analysed using Wilcoxon and Spearmans rho tests. Data regarding individual dogs (n=13), teams (n=52), dogs' placements in teams (n=4), and gang-line related pulling angles (n=104) was analysed. Overall, the position of the dogs was straighter when pulling in STICK, than when pulling in TRAD, with a median of 19 degrees (inter quartile range (IQR) 24.75 degrees) and 32 degrees (IQR 25.75 degrees), respectively (PPeer reviewe

Utilization of the Building-Block Approach in Structural Mechanics Research

In the last 20 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft safer and more affordable, extend their lifetime, improve their reliability, better understand their behavior, and reduce their weight. To support these efforts, research programs starting with ideas and culminating in full-scale structural testing were conducted at the NASA Langley Research Center. Each program contained development efforts that (a) started with selecting the material system and manufacturing approach; (b) moved on to experimentation and analysis of small samples to characterize the system and quantify behavior in the presence of defects like damage and imperfections; (c) progressed on to examining larger structures to examine buckling behavior, combined loadings, and built-up structures; and (d) finally moved to complicated subcomponents and full-scale components. Each step along the way was supported by detailed analysis, including tool development, to prove that the behavior of these structures was well-understood and predictable. This approach for developing technology became known as the "building-block" approach. In the Advanced Composites Technology Program and the High Speed Research Program the building-block approach was used to develop a true understanding of the response of the structures involved through experimentation and analysis. The philosophy that if the structural response couldn't be accurately predicted, it wasn't really understood, was critical to the progression of these programs. To this end, analytical techniques including closed-form and finite elements were employed and experimentation used to verify assumptions at each step along the way. This paper presents a discussion of the utilization of the building-block approach described previously in structural mechanics research and development programs at NASA Langley Research Center. Specific examples that illustrate the use of this approach are included from recent research and development programs for both subsonic and supersonic transports

Using novel palaeolimnological techniques to define conservation objectives for Hatch Mere: Report for Cheshire Wildlife Trust

This is the final report to Natural England on the project ‘Using novel palaeolimnological techniques to define lake conservation objectives for Hatch Mere’. The aim is to use existing and recently developed palaeoecological techniques to define reference conditions and assess the condition of Hatch Mere Special Scientific Interest (SSSIs) in the Cheshire meres, and thereby assist in the setting of conservation objectives and management goals. Two sediment cores (one open water and one marginal), approximately 1 m in length, were collected from Hatch Mere in August 2011. The cores were sampled at 1 cm intervals throughout and approximately ten samples from each site were analysed for diatoms, Cladocera, macrofossils, geochemistry (XRF) and pigments. The cores were dated using radiometric techniques in order to place the fossil remains within a known time frame. An existing diatom-total phosphorus (TP) transfer function was applied to the diatom data to reconstruct the nutrient history of the mere. The dating results suggest that the open water core (HAT3) extends back to ~1800 AD and the marginal core extends back beyond ~17o00 AD. The palaeoecological data indicate that the site has been a moderately enriched lake for the whole of the period represented by the cores with diatom-inferred TP concentrations of ~30 μg L-1 in the lower part of the record. However, there were marked changes across a range of indicators from the early 1800s indicative of enrichment, which has continued through the twentieth century. The key changes were the expansion of the eutrophic diatom species Cyclostephanos dubius and hence an increase in diatom-inferred TP to ~84 μg L-1, a steady increase in pigment concentrations from all algal groups, and shifts in the zooplankton community indicative of increased pelagic productivity. Eutrophication has resulted in marked changes in the aquatic plant community from a structurally diverse flora with abundant Charophytes, nymphaeids and taxa with a mix of seasonalities to the current state with no submerged flora and only Nuphar lutea. The most notable changes in the macrofossil record have occurred from the mid-1800s and are, therefore, coincident with the main phase of enrichment. The dominance of the upper sediments by planktonic zooplankton and abundant Daphnia ephippia towards the top of the core, lends further weight to a plankton dominated system. This study provides information on the plant and animal communities that were present in the lake prior to the major eutrophication phase and this significantly alters the generic target previously set for the lake and will be valuable for setting targets for future management of the site