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At least 271 records · Page 15

Effects of Different Mixing Agents on the Stability of Sodium Tetradecyl Sulfate (STS) Foam: An Experimental Study

PurposeTo evaluate the effect of air, CO{sub 2} and contrast medium-air on the dwell time (DT) stability of sodium tetradecyl sulfate (STS) foam.Materials and MethodsThree types of foam sclerosants (air-foam, CO{sub 2}-foam, contrast-air-foam) were injected eight times into an inclined straight plastic tube (internal diameters 4 mm and 10 mm) filled with a blood substitute. Injections were captured by CCD camera, and images were transferred for digital analysis and calculation of DT.ResultsContrast-air-foam and air-foam in a 4-mm tube showed 5.6-/3.3-fold greater DT compared to CO{sub 2}-foam, respectively (P = 0.001). Contrast-air-foam in a 10-mm tube showed 2.1-fold greater DT compared to CO{sub 2}-foam (P = 0.0167).ConclusionA mixture of air and iodinated contrast improves the stability of STS foam compared to mixtures using only air or CO{sub 2}. Further, animal and clinical studies are needed to validate this in vitro result.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Next Generation Qualification: Kinemetrics STS-5A Seismometer Evaluation

Sandia National Laboratories has tested and evaluated two seismometers, the STS-5A, manufactured by Kinemetrics. These seismometers measure three axes of broadband ground velocity using a UVW configuration with feedback control in a mechanically levelled borehole package. The purpose of the seismometer evaluation was to determine a measured sensitivity, response, self-noise, dynamic range, and self-calibration ability. The Kinemetrics STS-5A seismometers are being evaluated for the U.S. Air Force as part of their Next Generation Qualification effort.

47 OTHER INSTRUMENTATION↗

Second Target Station (STS) Project: Analysis of Bunker Shielding–Preliminary Design

At the Department of Energy’s Oak Ridge National Laboratory, the Second Target Station (STS) beamline sources for preliminary design have been used to perform a shielding analysis of the bunker. The simulations in this report used the ST11 beamline source, primarily the ST11 neutron source, because that source provides conservative prompt total dose rate estimates for all beamlines. Prompt total dose rates (i.e., neutron plus photon dose rates when the beam is on) were calculated on top of the bunker roof, outside the bunker wall, and in the basement below the bunker and instrument floor. Design changes were made to ensure the prompt total dose rate in these areas does not exceed 0.25 mrem/h. This report documents the required shielding thicknesses to meet this dose rate limit. There is one exception to this: for a combination of open and closed beamlines, the prompt total dose rate outside the bunker across from the closed beamline, where there is less shielding due to the lack of beamline shielding, slightly exceeds 0.25 mrem/h. A future analysis will document the shielding modifications required to reduce the calculated prompt total dose rates for this configuration to less than 0.25 mrem/h once more details regarding the STS high density concrete density and composition are known. Finally, prompt total dose rates inside the bunker were simulated. The results of this simulation show that the majority of prompt total dose rate in the bunker is due to neutrons, and a few percent of the total is caused by secondary photons created by the neutrons. The contribution to prompt total dose rate inside the bunker by the primary photons that enter each beamline from the target/moderator area is at least two orders of magnitude less than the neutron contribution. This means prompt total dose rate contributions due to primary photons inside and outside the bunker can be neglected.

42 ENGINEERING↗

TRACE Analysis of the STS Target Flow Loop Conceptual Design

This report documents the efforts to model the conceptual design of the STS natural circulation flow loop using TRACE. The results, summarized in Section 2.1, support the conclusion that the conceptual STS natural circulation flow loop design provides sufficient cooling of the tungsten target and exhibits predictable flow behavior, provided that certain design features and/or operating conditions are used. In particular: A sufficient initial liquid volume fraction is required to avoid dryout of the target flow channels; Inclusion of a pressurizer or bellows volume at the top of the loop is recommended and is capable of achieving steady, non-oscillatory flow and temperature conditions at sufficiently high loop pressure. Section 1 provides a detailed description of the geometry and assumptions used in the model, and Section 2 presents the results for the current flow loop design as well as some investigation of potential design modifications with the goal of enhancing the thermal hydraulic stability of the loop.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Second Target Station (STS) Project: PIONEER Technical Report

PIONEER is a time-of-flight single-crystal neutron diffractometer at the Second Target Station (STS), aiming at providing the world-leading capability to measure tiny crystals (~0.001 mm 3 , i.e., X-ray diffraction size), ultra-thin epitaxial films (~10 nm thicknesses), and weak structural transitions and complex magnetism. The instrument will take advantage of STS source characteristics and utilize advancements in neutron optics to largely reduce the sample-volume requirement for single-crystal neutron diffraction. PIONEER will have a high-flux mode with multiple beam size options to improve the signal-to-background ratio in various sample environments. It will also provide a high Q-resolution mode by limiting beam divergence to study periodically modulated structures with characteristic lengths no less than 100 Å. Furthermore, it supports half-polarized neutron diffraction for investigating complex magnetism and local susceptibility. This report first overviews the proposed science case and the derived requirement. And then, the chosen technical solutions and expected performance will be described.

36 MATERIALS SCIENCE↗

Use of STS subsystems and components for MMSE, volume 1

Multiuse mission support equipment (MMSE) is flight/ground equipment for the shuttle era which is used in conjunction with more than one mission payload. Initial verification of STS subsystem's applicability to MMSE is provided along with the cost savings potential and programmatic data needed for further program planning decisions. Some 70 MMSE requirements were found to be potentially satisfied by STS equipment, and and 6 items of particular interest were chosen for special emphasis. All were found to be feasible and beneficial. Program cost savings through their use are estimated to be substantial. Further study is recommended to identify additional MMSE requirements and hardware.

Source record↗

STS users study (study 2.2). Volume 1: Executive summary

The space transportation system (STS) and ancillary equipment user studies are presented. Space shuttle data and planning requirements needed by the STS user are discussed along with the potential for common usage of multi-mission support equipment by the military and other aerospace personnel.

Pritchard, E. I.↗

STS payloads mission control study continuation phase A-1. Volume 2-C, task 3: Identification of joint activities and estimation of resources in preparation for joint flight operations

Payload mission control concepts are developed for real time flight operations of STS. Flight planning, training, simulations, and other flight preparations are included. Payload activities for the preflight phase, activity sequences and organizational allocations, and traffic and experience factors to establish composite man-loading for joint STS payload activities are identified for flight operations from 1980 to 1985.

Source record↗

STS payloads mission control study phase A-1, volume 1, phases A and A-1

The Space Transportation System (STS) Payloads Mission Control Phase A-1 Study results are summarized. The composite resources required to accomplish Joint STS-Payload preflight preparation for joint flight operations, including flight planning, training, and simulations are presented. The Standard Payload Operations Control Center (POCC) concept was developed.

Source record↗

The STS pilot user development program

The planning and preparation activities and the results of the briefings associated with the Paris Air Show are described. A team of key personnel were available during the show to familiarize international users with the STS program and the space shuttle capabilities. Participation at the show included the operation of an STS booth at the U.S. pavilion, the presentation of several invitational briefings, and detailed discussions with individual organizations.

Mcdowell, J. R.↗

STS upper stage operations

Several design/development and operational approaches for STS upper stages are being pursued to realize maximum operational and economic benefits upon the introduction of the STS in the 1980s. The paper focuses special attention on safety operations, launch site operations and on-orbit operations.

Kitchens, M. D.↗

STS utilization planning

The paper shows how NASA plans to utilize the Shuttle to carry a wide variety of payloads. Topics covered include: Shuttle Transportation System (STS) description and capabilities, payload integration and manifesting payload business today, and NASA-JSC user services. Consideration is given to the flight assignment process and flight manifest which is a listing of flights with their attendant launch dates, payload names, days on-orbit, altitude, inclination, and crew required. Additional data such as weight, center of gravity, payload-on-orbit capability, and launch windows are checked to see if the manifest is still valid. The STS traffic model is described along with the small self-contained payloads.

Bauch, G. T.↗

Shuttle program. STS-7 feasibility assessment: IUS/TDRS-A

This Space Transportation System 7 (STS-7) Flight Feasibility Assessment (FFA) provides a base from which the various design, operation, and integration elements associated with Tracking and Data Relay Satellite-A can perform mission planning and analysis. The STS-7 FFA identifies conflicts, issues, and concerns associated with the integrated flight design requirements and constraints.

Source record↗

Safety of liquid propulsion systems for STS payloads

STS payload safety requirements for Earth-storable liquid propulsion systems are reviewed with respect to applicable safety documents. The effect of normal flight and emergency landing/abort launch profiles on propulsion system design is delineated. Spacecraft studied include Earth satellites, interplanetary spacecraft, and orbit transfer vehicles. Safety considerations for monopropellant (hydrazine), bipropellant (nitrogen tetroxide/monomethyl hydrazine), and ion (mercury) propulsion systems are described. Safety requirements for specific components of propulsion systems are reported. Analysis techniques for STS payload fracture control requirements for pressure vessels and critical support structure are discussed.

Lewis, J. C.↗

Atmospheric environment for space shuttle (STS-1) launch

Atmospheric conditions near space shuttle STS-1 launch time on April, 12, 1981, at Kennedy Space Center, Florida, are reported. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is presented. Also presented are the wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area. Final meteorological data tapes for STS-1 vehicle ascent, and SRB descent have been constructed which consist of wind and thermodynamic parameters versus altitude.

Johnson, D. L.↗

STS-2 Induced Environment Contamination Monitor (IECM): Quick-Look Report

The STS-2/induced environment contamination monitor (IECM) mission is described. The IECM system performance is discussed, and IECM mission time events are briefly described. Quick look analyses are presented for each of the 10 instruments comprising the IECM on the flight of STS-2. A short summary is presented.

Miller, E. R.↗

Preliminary analysis of STS-2 entry flight data

A preliminary analysis of the data obtained during the entry of the STS-2 flight was completed. The stability and control derivatives from STS-2 were examined. Questions still remain throughout the flight envelope and the area below Mach 3 needs more study. With three controls operating in a high gain feedback system, it is difficult to separate the individual effects of each of the controls. Analysis of the aerothermal data shows that wing structural-temperature measurements are generally repeatable and consistent with the trajectories. The measured wing upper surface temperatures are in reasonable agreement with Dryden predictions but wing lower surface temperatures are higher than Dryden predictions. Heating and heat transfer models will be adjusted to improve the temperature prediction capability for future trajectories.

Source record↗

Preliminary Analysis of STS-3 Entry Heat-Transfer Data for the Orbiter Windward Centerline

A preliminary analysis of heat transfer data on the space shuttle orbiter windward centerline for the STS-3 mission entry is presented. Temperature-time history plots for each measurement location and tabulated wall temperature and convective heating rate data at 21 selected trajectory points are included. The STS-3 flight data are also compared with predictions by two approximation methods for computing convective heat transfer rates in equilibrium air.

Throckmorton, D. A.↗