Active Control of Wind Tunnel Noise

The need for an adaptive active control system was realized, since a wind tunnel is subjected to variations in air velocity, temperature, air turbulence, and some other factors such as nonlinearity. Among many adaptive algorithms, the Least Mean Squares (LMS) algorithm, which is the simplest one, has been used in an Active Noise Control (ANC) system by some researchers. However, Eriksson's results, Eriksson (1985), showed instability in the ANC system with an ER filter for random noise input. The Restricted Least Squares (RLS) algorithm, although computationally more complex than the LMS algorithm, has better convergence and stability properties. The ANC system in the present work was simulated by using an FIR filter with an RLS algorithm for different inputs and for a number of plant models. Simulation results for the ANC system with acoustic feedback showed better robustness when used with the RLS algorithm than with the LMS algorithm for all types of inputs. Overall attenuation in the frequency domain was better in the case of the RLS adaptive algorithm. Simulation results with a more realistic plant model and an RLS adaptive algorithm showed a slower convergence rate than the case with an acoustic plant as a delay plant. However, the attenuation properties were satisfactory for the simulated system with the modified plant. The effect of filter length on the rate of convergence and attenuation was studied. It was found that the rate of convergence decreases with increase in filter length, whereas the attenuation increases with increase in filter length. The final design of the ANC system was simulated and found to have a reasonable convergence rate and good attenuation properties for an input containing discrete frequencies and random noise

Lunar surface operations. Volume 1: Lunar surface emergency shelter

The lunar surface emergency shelter (LSES) is designed to provide survival-level accommodations for up to four astronauts for a maximum of five days. It would be used by astronauts who were caught out in the open during a large solar event. The habitable section consists of an aluminum pressure shell with an inner diameter of 6 ft. and a length of 12.2 ft. Access is through a 4 in. thick aluminum airlock door mounted at the rear of the shelter. Shielding is provided by a 14.9 in. thick layer of lunar regolith contained within a second, outer aluminum shell. This provides protection against a 200 MeV event, based on a 15 REM maximum dose. The shelter is self-contained with a maximum range of 1000 km. Power is supplied by a primary fuel cell which occupies 70.7 cu ft. of the interior volume. Mobility is achieved by towing the shelter behind existing lunar vehicles. It was assumed that a fully operational, independent lunar base was available to provide communication support and tools for set-up and maintenance. Transportation to the moon would be provided by the proposed heavy lift launch vehicle. Major design considerations for the LSES were safety, reliability, and minimal use of earth materials

Lunar surface operations. Volume 4: Lunar rover trailer

The purpose of the project was to design a lunar rover trailer for exploration missions. The trailer was designed to carry cargo such as lunar geological samples, mining equipment and personnel. It is designed to operate in both day and night lunar environments. It is also designed to operate with a maximum load of 7000 kilograms. The trailer has a ground clearance of 1.0 meters and can travel over obstacles 0.75 meters high at an incline of 45 degrees. It can be transported to the moon fully assembled using any heavy lift vehicle with a storage compartment diameter of 5.0 meters. The trailer has been designed to meet or exceed the performance of any perceivable lunar vehicle

Lunar surface operations. Volume 3: Robotic arm for lunar surface vehicle

A robotic arm for a lunar surface vehicle that can help in handling cargo and equipment, and remove obstacles from the path of the vehicle is defined as a support to NASA's intention to establish a lunar based colony by the year 2010. Its mission would include, but not limited to the following: exploration, lunar sampling, replace and remove equipment, and setup equipment (e.g. microwave repeater stations). Performance objectives for the robotic arm include a reach of 3 m, accuracy of 1 cm, arm mass of 100 kg, and lifting capability of 50 kg. The end effectors must grip various sizes and shapes of cargo; push, pull, turn, lift, or lower various types of equipment; and clear a path on the lunar surface by shoveling, sweeping aside, or gripping the obstacle present in the desired path. The arm can safely complete a task within a reasonable amount of time; the actual time is dependent upon the task to be performed. The positioning of the arm includes a manual backup system such that the arm can be safely stored in case of failure. Remote viewing and proximity and positioning sensors are incorporated in the design of the arm. The following specific topic are addressed in this report: mission and requirements, system design and integration, mechanical structure, modified wrist, structure-to-end-effector interface, end-effectors, and system controls

Wait Line Behaviors at Restaurants during COVID-19

We were assigned to do field work observations through a series of individual data collection sessions. My group member and I choose to do observations at restaurants to see how covid has impacted waiting in line due to their facility reaching capacity. We each chose different locations to observe and collect data. Within this research project, we were able to identify different behaviors of people waiting. Some people were patient, kind, and courteous while other’s were impatient and rude. These observations were made by each observer at these different locations

On the Development of the Artillery Flight Characterization Electronics Rescue Kit

21st AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, 23 - 26 May 2011, Dublin, IrelandThis paper investigates a prospective avionics suite rescue kit to salvage some of the state-of-the-art electronics in the data-collecting fuze system employed on an artillery projectile. A single-use data collection fuze is currently in use by the Army that relays sensor measurements for the purpose of characterizing the flight of an artillery projectile. The goal of the present study is to develop a parachute/parafoil-based system to be deployed automatically at apogee, so that the ! Reuse-Fuze" becomes separated from the body of the artillery shell and safely recovered. The paper presents the overall design of the Reuse-Fuze system, including the release mechanism, deceleration system, and impact survivability considerations. The successful design of a recoverable and reusable fuze-shaped data collection system will allow the Army to conduct repeated artillery testing without increasing the cost of expensive electronics hardware

Single nucleotide polymorphisms (SNPs) distinguish Indian-origin and Chinese-origin rhesus macaques (Macaca mulatta)

BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3' end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis. RESULTS: We surveyed the 3' end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific. CONCLUSION: This study demonstrates that the 3' end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations

Single Nucleotide Polymorphisms (SNPs) Distinguish Indian-Origin and Chinese-Origin Rhesus Macaques (Macaca Mulatta)

BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3\u27 end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis. RESULTS: We surveyed the 3\u27 end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific. CONCLUSION: This study demonstrates that the 3\u27 end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations

Performance of a Carbon Nanotube Field Emission Electron Gun

A cold cathode field emission electron gun (e-gun) based on a patterned carbon nanotube (CNT) film has been fabricated for use in a miniaturized reflectron time-of-flight mass spectrometer (RTOF MS). Performance of the CNT e-gun has been evaluated. A traditional thermionic electron gun has also been fabricated and evaluated in parallel and its performance is used as a benchmark in the evaluation of our CNT e-gun. Implications for future improvements and integration into the RTOF MS are discussed