662 research outputs found
The Range Safety Debris Catalog Analysis in Preparation for the Pad Abort One Flight Test
The Pad Abort One flight test of the Orion Abort Flight Test Program is currently under development with the goal of demonstrating the capability of the Launch Abort System. In the event of a launch failure, this system will propel the Crew Exploration Vehicle to safety. An essential component of this flight test is range safety, which ensures the security of range assets and personnel. A debris catalog analysis was done as part of a range safety data package delivered to the White Sands Missile Range in New Mexico where the test will be conducted. The analysis discusses the consequences of an overpressurization of the Abort Motor. The resulting structural failure was assumed to create a debris field of vehicle fragments that could potentially pose a hazard to the range. A statistical model was used to assemble the debris catalog of potential propellant fragments. Then, a thermodynamic, energy balance model was applied to the system in order to determine the imparted velocity to these propellant fragments. This analysis was conducted at four points along the flight trajectory to better understand the failure consequences over the entire flight. The methods used to perform this analysis are outlined in detail and the corresponding results are presented and discussed
Possibilities of Fabricating Copper-based RFID Tags with Photonic-sintered Inkjet Printing and Thermal Transfer Printing
This letter studies the possibilities of manufacturing copper-based passive UHF RFID tags using inkjet and thermal printing on two substrate materials, polyimide (Kapton) and a polyester based substrate (Flexcon THERMLfilm). Both printing methods are tested to fabricate different tag designs, and the performance of successfully printed tags is evaluated using wireless measurements. Measurement results show that both the printing methods, while using copper material, can be used to effectively fabricate passive UHF RFID tag antennas on selected substrates
Mars Science Laboratory Entry, Descent, and Landing Trajectory and Atmosphere Reconstruction
On August 5th 2012, The Mars Science Laboratory entry vehicle successfully entered Mars atmosphere and landed the Curiosity rover on its surface. A Kalman filter approach has been implemented to reconstruct the entry, descent, and landing trajectory based on all available data. The data sources considered in the Kalman filtering approach include the inertial measurement unit accelerations and angular rates, the terrain descent sensor, the measured landing site, orbit determination solutions for the initial conditions, and a new set of instrumentation for planetary entry reconstruction consisting of forebody pressure sensors, known as the Mars Entry Atmospheric Data System. These pressure measurements are unique for planetary entry, descent, and landing reconstruction as they enable a reconstruction of the freestream atmospheric conditions without any prior assumptions being made on the vehicle aerodynamics. Moreover, the processing of these pressure measurements in the Kalman filter approach enables the identification of atmospheric winds, which has not been accomplished in past planetary entry reconstructions. This separation of atmosphere and aerodynamics allows for aerodynamic model reconciliation and uncertainty quantification, which directly impacts future missions. This paper describes the mathematical formulation of the Kalman filtering approach, a summary of data sources and preprocessing activities, and results of the reconstruction
Coupled Inertial Navigation and Flush Air Data Sensing Algorithm for Atmosphere Estimation
This paper describes an algorithm for atmospheric state estimation that is based on a coupling between inertial navigation and flush air data sensing pressure measurements. In this approach, the full navigation state is used in the atmospheric estimation algorithm along with the pressure measurements and a model of the surface pressure distribution to directly estimate atmospheric winds and density using a nonlinear weighted least-squares algorithm. The approach uses a high fidelity model of atmosphere stored in table-look-up form, along with simplified models of that are propagated along the trajectory within the algorithm to provide prior estimates and covariances to aid the air data state solution. Thus, the method is essentially a reduced-order Kalman filter in which the inertial states are taken from the navigation solution and atmospheric states are estimated in the filter. The algorithm is applied to data from the Mars Science Laboratory entry, descent, and landing from August 2012. Reasonable estimates of the atmosphere and winds are produced by the algorithm. The observability of winds along the trajectory are examined using an index based on the discrete-time observability Gramian and the pressure measurement sensitivity matrix. The results indicate that bank reversals are responsible for adding information content to the system. The algorithm is then applied to the design of the pressure measurement system for the Mars 2020 mission. The pressure port layout is optimized to maximize the observability of atmospheric states along the trajectory. Linear covariance analysis is performed to assess estimator performance for a given pressure measurement uncertainty. The results indicate that the new tightly-coupled estimator can produce enhanced estimates of atmospheric states when compared with existing algorithms
Mars Entry Atmospheric Data System Trajectory Reconstruction Algorithms and Flight Results
The Mars Entry Atmospheric Data System is a part of the Mars Science Laboratory, Entry, Descent, and Landing Instrumentation project. These sensors are a system of seven pressure transducers linked to ports on the entry vehicle forebody to record the pressure distribution during atmospheric entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. Specifically, angle of attack, angle of sideslip, dynamic pressure, Mach number, and freestream atmospheric properties are reconstructed from the measured pressures. Such data allows for the aerodynamics to become decoupled from the assumed atmospheric properties, allowing for enhanced trajectory reconstruction and performance analysis as well as an aerodynamic reconstruction, which has not been possible in past Mars entry reconstructions. This paper provides details of the data processing algorithms that are utilized for this purpose. The data processing algorithms include two approaches that have commonly been utilized in past planetary entry trajectory reconstruction, and a new approach for this application that makes use of the pressure measurements. The paper describes assessments of data quality and preprocessing, and results of the flight data reduction from atmospheric entry, which occurred on August 5th, 2012
Performance comparison of inkjet and thermal transfer printed passive ultra-high-frequency radio-frequency identification tags
The authors compare the maximum read range of passive ultra-high-frequency radio-frequency identification tags that have been produced using different metal printing techniques, specifically inkjet printing and thermal transfer printing (TTP). They used the same substrate (THERMLfilm), antenna designs and electronic circuitry in their comparison so as to isolate the effect of the metal printing. Owing to the high metal conductivity, the thermal transfer printed tags printed with copper (Cu) film performed as well or better than the inkjet printed tags printed with silver ink, even when they changed the inkjet printed tags to a Kapton substrate that is better suited to inkjet printing. The aluminium (Al) thermal transfer printed tags had up to 33% less read range than Cu thermal transfer printed tags. TTP needs no sintering, and provides an attractive alternative low-cost fabrication method. Characterisation of the printed traces by both methods reveals that the printing techniques achieve similar surface roughness. The achieved conductivities for TTP on THERMLfilm were better than for inkjet. The best measured read range for TTP was 10.6 m. Across the different tag designs, the measured read ranges were 15-60% (1-10%) better for thermal printing, compared with inkjet printing on THERMLfilm (Kapton)
MiR-133a Mimic Alleviates T1DM-Induced Systolic Dysfunction in Akita: An MRI-Based Study
Diabetic cardiomyopathy is a leading cause of heart failure. Developing a novel therapeutic strategy for diabetic cardiomyopathy and characterizing animal models used for diabetes mellitus (DM) are important. Insulin 2 mutant (Ins2+/-) Akita is a spontaneous, genetic, mouse model for T1DM, which is relevant to humans. There are contrasting reports on systolic dysfunction and pathological remodeling (hypertrophy and fibrosis) in Akita heart. Here, we used magnetic resonance imaging (MRI) approach, a gold standard reference for evaluating cardiac function, to measure ejection fraction (indicator of systolic dysfunction) in Akita. Moreover, we performed Wheat Germ Agglutinin (WGA) and hematoxylin and Eosin stainings to determine cardiac hypertrophy, and Masson\u27s Trichrome and picrosirius red stainings to determine cardiac fibrosis in Akita. MiR-133a, an anti-hypertrophy and anti-fibrosis miRNA, is downregulated in Akita heart. We determined if miR-133a mimic treatment could mitigate systolic dysfunction and remodeling in Akita heart. Our MRI results revealed decreased ejection fraction in Akita as compared to WT and increased ejection fraction in miR-133a mimic-treated Akita. We also found that miR-133a mimic treatment mitigates T1DM-induced cardiac hypertrophy and fibrosis in Akita. We conclude that Akita shows cardiac hypertrophy, fibrosis and systolic dysfunction and miR-133a mimic treatment to Akita could ameliorate them
Placental transfer of pesticides in humans
Transfer of organochlorine pesticides from mother to fetus has been studied in 100 women. The concentrations of organochlorine pesticides were examined in maternal blood, placenta, and umbilical cord blood of the same mother/child pair. Residue levels of dichlorodiphenyl trichloro ethane (DDT) and its metabolites, isomers of benzene hexachloride (BHC) and aldrin were detected in all the samples analyzed, indicating their transfer from mother to the fetus. A correlation was found to exist between the pesticide concentration and age, dietetic habits and area of residence of pregnant women
NICNET - a Hierarchic distributed computer-communication network for decision support in the Indian Government
A decision support information system for the Indian Government is being evolved, based on the design of a predominantly query-based computer network with hierarchric distributed databases and random access communication. The four level hierarchy spans 439 districts at the lowest level, the Central Government headquarters in New Delhi, the set of 32 State Capitals and Union Territories, and the set of four Regional Centres. With interference tolerance and random access as two guiding principles behind the choice, Spread Spectrum transmission and Code Division Multiple Access system of satellite communication was adopted. Each node of the network is a 32-bit computer which is capable of local bulk storage of up to three units of 300 megabytes each for purposes of queryaccessible distributed databases. The design and implementation of such a distributed database has endowed the network with the capability to distribute the data related to such databases over various nodes in the network so as to be able to accept a query from any of the nodes
Assessment of the Reconstructed Aerodynamics of the Mars Science Laboratory Entry Vehicle
On August 5, 2012, the Mars Science Laboratory entry vehicle successfully entered Mars atmosphere, flying a guided entry until parachute deploy. The Curiosity rover landed safely in Gale crater upon completion of the Entry Descent and Landing sequence. This paper compares the aerodynamics of the entry capsule extracted from onboard flight data, including Inertial Measurement Unit (IMU) accelerometer and rate gyro information, and heatshield surface pressure measurements. From the onboard data, static force and moment data has been extracted. This data is compared to preflight predictions. The information collected by MSL represents the most complete set of information collected during Mars entry to date. It allows the separation of aerodynamic performance from atmospheric conditions. The comparisons show the MSL aerodynamic characteristics have been identified and resolved to an accuracy better than the aerodynamic database uncertainties used in preflight simulations. A number of small anomalies have been identified and are discussed. This data will help revise aerodynamic databases for future missions and will guide computational fluid dynamics (CFD) development to improved prediction codes
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