Diffusion welding tool

Tool allows flat plate diffusion welding to be done in standard brazing furnace. Weld is achieved using high water pressure applied by hand-operated positive-displacement pump. Good welds have been obtained between nickel and nickel-base alloy plates at temperature of 1200 K and water pressure of 13.8 million N/sq m

Thermal Skin fabrication technology

Advanced fabrication techniques applicable to Thermal Skin structures were investigated, including: (1) chemical machining; (2) braze bonding; (3) diffusion bonding; and (4) electron beam welding. Materials investigated were nickel and nickel alloys. Sample Thermal Skin panels were manufactured using the advanced fabrication techniques studied and were structurally tested. Results of the program included: (1) development of improved chemical machining processes for nickel and several nickel alloys; (2) identification of design geometry limits; (3) identification of diffusion bonding requirements; (4) development of a unique diffusion bonding tool; (5) identification of electron beam welding limits; and (6) identification of structural properties of Thermal Skin material

Results of investigations on a 0.010-scale model of the configuration 3 space shuttle orbiter and external tank in the NASA/Ames Research Center 3.5-foot hypersonic wind tunnel (IA15)

Experimental aerodynamic investigations were conducted in a 3.5-foot hypersonic wind tunnel. The model used for this test was a 0.010-scale of the Configuration 2 Space Shuttle Orbiter and the External Tank. Six-component aerodynamic force and moment data were recorded over an angle of attack range from -8 deg to +30 deg at 0 deg and 5 deg angles of sideslip. Data was also recorded during beta sweeps of -8 deg to +10 deg at angles of attack of -10 deg, 0 deg, and 30 deg. All testing was done at Mach 7.3. Various elevon, rudder and orbiter to external tank attaching structures and fairings were tested to determine longitudinal and lateral-directional stability characteristics. Non-metric exhaust plumes were installed during a portion of the testing to determine the effects of the main propulsion system rocket plumes

Results of tests of a 0.010- and 0.015-scale models of space shuttle orbiter configurations 3 and 3A in the Ames Research Center 3.5 foot hypersonic wind tunnel (OA23)

Longitudinal and lateral-directional stability and control characteristics were evaluated at Mach numbers of 5.3, 7.3 and 10.3 at angles of attack up to 50 degrees with Beta = 0 degrees and, for a few cases, Beta = 5 degrees. Component force data, fuselage base pressures and shadowgraph patterns were recorded

Results of investigations of an 0.010-scale 140A/B configuration (model 72-OTS) of the Rockwell International space shuttle orbiter in the NASA/Langley Research Center unitary plan wind tunnel

Experimental aerodynamic investigations were conducted in the NASA/Langley unitary plan wind tunnel on a sting mounted 0.010-scale outer mold line model of the 140A/B configuration of the Rockwell International Space Shuttle Vehicle. The primary test objectives were to obtain: (1) six component force and moment data for the mated vehicle at subsonic and transonic conditions, (2) effects of configuration build-up, (3) effects of protuberances, ET/orbiter fairings and attach structures, and (4) elevon deflection effects on wing bending moment. Six component aerodynamic force and moment data and base and balance cavity pressures were recorded over Mach numbers of 1.6, 2.0, 2.5, 2.86, 3.9, and 4.63 at a nominal Reynolds number of 20 to the 6th power per foot. Selected configurations were tested at angles of attack and sideslip from -10 deg to +10 deg. For all configurations involving the orbiter, wing bending, and torsion coefficients were measured on the right wing

Results of transonic wind tunnel tests on an 0.010-scale space shuttle mated vehicle model 72-OTS in the LaRC 8-foot TPT (IA43)

Experimental aerodynamic investigations were conducted in NASA/Langley 8-Foot transonic pressure tunnel on a sting mounted 0.010-scale outer mold line model of 104A/B configuration of the Rockwell International space shuttle vehicle. Component aerodynamic force and moment data and base and balance cavity pressures were recorded over an angle of attack range of -10 deg to +10 deg at Mach numbers of 0.6, 0.8, 0.9, 0.98, 1.13, and 1.2. Selected configurations were tested at sideslip angles from -10 deg to +10 deg. For all configurations involving the orbit, wing bending and torsion were measured on the right wing. Inboard elevon setting of 0 deg, +4 deg and +8 deg and outboard settings of 0 deg, +4 deg and +8 deg were tested

Reference Sediment Selection in the Lower Mississippi Delta

Floodplain deposition has been a critical part in the evolution of Arkansas\u27 Delta ecoregion, and because ofits high potential for such events, this region is highly enriched and extremely fertile. Historically, water quality in the area has been the subject ofscientific study, and as a result littlehas been published on the effects of underlying sediment with associated benthic communities. Sediment analysis is critical to many of the ongoing aquatic studies because ofits significance as both a habitat for benthic organisms and a sink for contaminants. Seven rivers and one creek within the Delta ecoregion were examined for water chemistry, sediment characterization, and sediment toxicity to determine survival and growth of Chironomus tentans. Greatest midge growth occurred insediment collected from Black River site A; additionally, those sediments were high in silt content (\u3e80%) and supported high midge survival. The results of combined characterization and biological test methods indicated that the Black River (site A) was the sediment that met criteria set by the researchers and was suitable to use as a reference control sediment forfuture Delta toxicity testing

Results of investigations on a 0.015-scale model (49-0) of the space shuttle orbiter in the NASA/Ames 3.5-foot hypersonic wind tunnel (OA87)

Experimental aerodynamic investigations were conducted on a scale model of the space shuttle orbiter, Configuration 140A/B. The objectives of this test were to: 1) verify supersonic stability and control characteristics, 2) analyze aerodynamic problem areas, 3) verify control surface effectiveness, and 4) investigate Reynolds number effects. Six-component aerodynamic force and moment data were recorded over an angle of attack range from 22 deg to 46 deg at a constant sideslip angle of 0 deg. The test Mach number was varied from 5.3 to 7.3 to 10.3. The Reynolds number per unit length was varied from 805,000 to 10 million per foot

In-Stream Monitoring of Sediments and Water in the Lower Ouachita River for Site Impact to Aquatic Biota

Reported reduced sportfish densities in the main channel of the Ouachita River prompted an investigation, beginning in 1990, into potential causes of ongoing impairment to aquatic biota. In-stream monitoring that incorporated toxicity testing of sediments and water was conducted to discern potential sources of contaminants that might be related to the suboptimal fishery populations. Organisms selected to evaluate chronic impairment included larval fish, clams, midges and water fleas. The fathead minnow {Pimephales promelas) and cladoceran (Ceriodaphnia dubid) were used to estimate patterns of toxicity associated with water from seven designated reaches and selected tributaries of the Ouachita River. Larval survival and growth tests were conducted using the fathead minnow, while survival and reproduction were assessed for the cladoceran. An enzyme assay using the Asian clam (Corbicula fluminea), and growth and survival tests with Chironomus tentans were used to evaluate ambient sediment toxicity within these same reaches and tributaries. Ambient toxicity was rarely observed in the mainstem of the River and, moreover, represented intermittent events. However, impaired growth in larval fish, poor reproduction in cladocera, and reduced enzyme activity in clams were evident for several tributaries. Results of 10-day whole sediment tests showed significant growth reductions in C. tentans exposed to sediments collected from West and East Two bayous, Smackover and Coffee creeks. These results suggest there is intermittent impairment in tributaries of the Ouachita River due to ambient water and sediment conditions that are aside from current concerns for mercury contamination