Defect Depth Measurement Using White Light Interferometry

The objectives of the White Light Interferometry project are the following: (1) Demonstrate a small hand-held instrument capable of performing inspections of identified defects on Orbiter outer pane window surfaces. (2) Build and field-test a prototype device using miniaturized optical components. (3) Modify the instrument based on field testing and begin the conversion of the unit to become a certified shop-aid

Developing NDE Techniques for Large Cryogenic Tanks

The Shuttle and Constellation Programs require very large cryogenic ground storage tanks in which to store liquid oxygen and hydrogen. The existing LC-39 pad tanks, which will be passed onto Constellation, are 40 years old and have received minimal refurbishment or even inspection, because they can only be temperature cycled a few times before being overhauled (a costly operation in both time and dollars). Numerous questions exist on the performance and reliability of these old tanks which could cause a major Program schedule disruption. Consequently, with the passing of the first two tanks to Constellation to occur this year, there is growing awareness that NDE is needed to detect problems early in these tanks so that corrective actions can be scheduled when least disruptive. Time series thermal images of two sides of the Pad B LH2 tank have been taken over multiple days to demonstrate the effects of environmental conditions to the solar heating of the tank and therefore the effectiveness of thermal imaging

The Development of NDE Techniques for Large Cryogenic Storage Tanks

Objectives of this project are: (1) Develop and demonstrate NDE techniques to evaluate the condition of large cryogenic Dewars (typically 50,000 to 900,000 gaL). (2) These tanks are used across NASA for launch pads, engine test stands, cryogenic wind tunnels and other facilities: they represent a major investment. (3) Issues addressed: (1) Insulation integrity of existing Dewars (powdered insulation under vacuum or sometimes ambient pressure (LO2), (2) Post fabrication insulation verification without full chill-down to avoid thermal cycling the tank (fatigue limitation of piping and compaction of Perlite)

The Future Flight Deck: Modelling Dual, Single and Distributed Crewing Options

It is argued that the barrier to single pilot operation is not the technology, but the failure to consider the whole socio-technical system. To better understand the socio-technical system we model alternative single pilot operations using Cognitive Work Analysis (CWA) and analyse those models using Social Network Analysis (SNA). Four potential models of single pilot operations were compared to existing two pilot operations. Using SOCA-CAT from CWA, we were able to identify the potential functional loading and interactions between networks of agents. The interactions formed the basis on the SNA. These analyses potentially form the basis for distributed system architecture for the operation of a future aircraft. The findings from the models suggest that distributed crewing option could be at least as resilient, in network architecture terms, as the current dual crewing operations

Spot the difference: Operational event sequence diagrams as a formal method for work allocation in the development of single-pilot operations for commercial aircraft

Function Allocation methods are important for the appropriate allocation of tasks between humans and automated systems. It is proposed that Operational Event Sequence Diagrams (OESDs) provide a simple yet rigorous basis upon which allocation of work can be assessed. This is illustrated with respect to a design concept for a passenger aircraft flown by just a single pilot where the objective is to replace or supplement functions normally undertaken by the second pilot with advanced automation. A scenario-based analysis (take off) was used in which there would normally be considerable demands and interactions with the second pilot. The OESD analyses indicate those tasks that would be suitable for allocation to automated assistance on the flight deck and those tasks that are now redundant in this new configuration (something that other formal Function Allocation approaches cannot identify). Furthermore, OESDs are demonstrated to be an easy to apply and flexible approach to the allocation of function in prospective systems.Practitioner Summary: OESDs provide a simple yet rigorous basis upon which allocation of work can be assessed. The technique can deal with the flexible, dynamic allocation of work and the deletion of functions no longer required. This is illustrated using a novel design concept for a single-crew commercial aircraf

Municipal Government Transition in Denton, Texas

Transition in the form of municipal government is always a complex and challenging task. The process involves serious risks of instability in a municipality's affairs, and this in turn may have adverse consequences for the community as a whole. But at the same time, changes in the form of government and in the personnel responsible for the management of public affairs may hold promise of improvements, which will benefit a city and its citizens. This thesis examines the experience of Denton, Texas, in making a transition from a mayor-commission to a council-manager form of government. T his major governmental change in Denton required several years. The period of transition examined in this study will be from 1955 to the end of 1961

Developing NDE Techniques for Orion Crew Module

Project: The Orion Crew Module (CM) and Service Module (SM) subsystems will require approximately 870 tube welds to be fabricated onsite at KSC O&C High Bay. A quick and reliable NDE technique is required to ensure efficient assembly and superior weld quality

Measurement and modeling of moist processes

The keynote talk summarized five years of work simulating observed mesoscale convective systems with the RAMS (Regional Atmospheric Modeling System) model. Excellent results are obtained when simulating squall line or other convective systems that are strongly forced by fronts or other lifting mechanisms. Less highly forced systems are difficult to model. The next topic in this colloquium was measurement of water vapor and other constituents of the hydrologic cycle. Impressive accuracy was shown measuring water vapor with both the airborne DIAL (Differential Absorption Lidar) system and the the ground-based Raman Lidar. NMC's plans for initializing land water hydrology in mesoscale models was presented before water vapor measurement concepts for GCIP were discussed. The subject of using satellite data to provide mesoscale moisture and wind analyses was next. Recent activities in modeling of moist processes in mesoscale systems was reported on. These modeling activities at the Canadian Atmospheric Environment Service (AES) used a hydrostatic, variable-resolution grid model. Next the spatial resolution effects of moisture budgets was discussed; in particular, the effects of temporal resolution on heat and moisture budgets for cumulus parameterization. The conclusion of this colloquium was on modeling scale interaction processes

The Immunosuppressive Properties of the HIV Vpr Protein Are Linked to a Single Highly Conserved Residue, R90

BACKGROUND: A hallmark of AIDS progression is a switch of cytokines from Th1 to Th2 in the plasma of patients. IL-12, a critical Th1 cytokine secreted by antigen presenting cells (APCs) is suppressed by Vpr, implicating it as an important virulence factor. We hypothesize that Vpr protein packaged in the virion may be required for disabling APCs of the first infected mucosal tissues. Consistent with this idea are reports that defects in the C-terminus of Vpr are associated with long-term non-progression. PRINCIPAL FINDINGS: Vpr RNA amplified from various sources was electroporated into monocyte-derived DC and IL-12 levels in supernatants were analyzed. The analysis of previously reported C-terminal Vpr mutations demonstrate that they do not alleviate the block of IL-12 secretion. However, a novel single conservative amino acid substitution, R90K, reverses the IL-12 suppression. Analysis of 1226 Vpr protein sequences demonstrated arginine (R) present at position 90 in 98.8%, with other substitutions at low frequency. Furthermore, none of sequences report lysine (K) in position 90. Vpr clones harboring the reported substitutions in position 90 were studied for their ability to suppress IL-12. Our data demonstrates that none of tested substitutions other than K relieve IL-12 suppression. This suggests a natural selection for sequences which suppress IL-12 secretion by DC and against mutations which relieve such suppression. Further analyses demonstrated that the R90K, as well as deletion of the C-terminus, directs the Vpr protein for rapid degradation. CONCLUSION: This study supports Vpr as an HIV virulence factor during HIV infection and for the first time provides a link between evolutionary conservation of Vpr and its ability to suppress IL-12 secretion by DC. DC activated in the presence of Vpr would be defective in the production of IL-12, thus contributing to the prevailing Th2 cytokine profile associated with progressive HIV disease. These findings should be considered in the design of future immunotherapies that incorporate Vpr as an antigen