The Apollo Auxiliary Power Supply System, Project Apollo

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Trends in the Improving Economic use of Aluminium

INDUSTRIAL usage of aluminium is increasing at a rate of about 10% every year . Whereas in 1958 the total world production of primary metal was rather less than 4 in short tons, in 1968 it is expected to be over 9 m tons. The reasons leading to the initial usage of aluminium for any given application are usually either technical or strategic. Considerations of weight, durability, appearance or conductivity may lead to the adoption of aluminium in preference to other materials or, alternatively, shortages of domestic supplies of other materials and of foreign exchange, may dictate the employment of locally produced aluminium

Trends in the Improving Economic use of Aluminium

The reasons leading to the initial usage of alum-inium for any given application are usually either technical or strategic. Considerations of weight, dura-bility, appearance or conductivity may lead to the adop-tion of aluminium in preference to other materials or, alternatively, shortages of domestic supplies of other materials and of foreign exchange, may dictate the employment of locally produced aluminium

Direct versus Delayed pathways in Strong-Field Non-Sequential Double Ionization

We report full-dimensionality quantum and classical calculations for double ionization of laser-driven helium at 390 nm. Good qualitative agreement is observed. We show that the classical double ionization trajectories can be divided into two distinct pathways: direct and delayed. The direct pathway, with an almost simultaneous ejection of both electrons, emerges from small laser intensities. With increasing intensity its relative importance, compared to the delayed ionization pathway, increases until it becomes the predominant pathway for total electron escape energy below around 5.25 $U_{p}$. However the delayed pathway is the predominant one for double ionization above a certain cut-off energy at all laser intensities

Effect of longitudinal surface finish on elastohydrodynamic lubrication

The effect of longitudinal-lay surface finish on the elastohydrodynamic film thickness and the percentage of film between rolling disks in contact were evaluated using a rolling disk apparatus. Film thickness was measured by transmitted X-rays, and percentage of film was monitored by an alternating-current continuity circuit. Disk finish was varied on both the crowned upper disk and the cylindrical lower disk. A type-2 ester and a synthetic paraffinic oil were used as lubricants. It was shown that the roughness with longitudinal lay has a deleterious effect on both film thickness and percentage of film. Measured film thicknesses for the two lubricants were comparable at equivalent test conditions. The percentage of film where a change in surface topography was observed was approximately 20 percent for the synthetic paraffinic oil and 10 percent for the type-2 ester

Exit plane H2O concentration measurements correlated with OH PLIF near-injector mixing measurements for scramjet flows

Mixing and combusting high enthalpy flows, similar to those encountered in scramjet engines, were investigated using a shock tunnel to produce the flow in conjunction with non-intrusive optical diagnostics which monitored the performance of two injector configurations. The shock tunnel is configured to produce Mach 3 flow and stagnation enthalpies corresponding to flight equivalent Mach numbers between 7 and 11. A pulsed hydrogen injection capability and interchangeable injector blocks provide a means of examining high speed, high enthalpy reacting flows. Planar laser induced fluorescence (PLIF) of OH molecules in the near injector region produced images which show the combusting and mixing zones for the reacting flow. Line-of-sight exit plane measurement of water concentration and temperature were used to provide a unique method of monitoring exit plane products. These results demonstrated that a velocity matched axial injection system produced a fuel jet that lifted off the floor of the duct. Mixing was observed to increase for this system as a velocity mismatch was introduced. Comparison of exit plane water concentrations for a wall jet injection system and a velocity matched injection system indicated similar mixing performance but an accurate pressure measurement is necessary to further validate the result. In addition, exit plane measurements indicated an approximate steady-state condition was achieved during the 1 to 2 ms test times

Trophic Transfer of Arsenic from an Aquatic Insect to Terrestrial Insect Predators.

The movement of energy and nutrients from aquatic to terrestrial ecosystems can be substantial, and emergent aquatic insects can serve as biovectors not only for nutrients, but also for contaminants present in the aquatic environment. The terrestrial predators Tenodera aridifolia sinensis (Mantodea: Mantidae) and Tidarren haemorrhoidale (Araneae: Theridiidae) and the aquatic predator Buenoa scimitra (Hemiptera: Notonectidae) were chosen to evaluate the efficacy of arsenic transfer between aquatic and terrestrial environments. Culex tarsalis larvae were reared in either control water or water containing 1000 µg l(-1) arsenic. Adults that emerged from the control and arsenic treatments were fed to the terrestrial predators, and fourth instar larvae were fed to the aquatic predator reared in control or arsenic contaminated water. Tenodera a. sinensis fed arsenic-treated Cx. tarsalis accumulated 658±130 ng g(-1) of arsenic. There was no significant difference between control and arsenic-fed T. haemorrhoidale (range 142-290 ng g(-1)). Buenoa scimitra accumulated 5120±406 ng g(-1) of arsenic when exposed to arsenic-fed Cx. tarsalis and reared in water containing 1000 µg l(-1) arsenic. There was no significant difference between controls or arsenic-fed B. scimitra that were not exposed to water-borne arsenic, indicating that for this species environmental exposure was more important in accumulation than strictly dietary arsenic. These results indicate that transfer to terrestrial predators may play an important role in arsenic cycling, which would be particularly true during periods of mass emergence of potential insect biovectors. Trophic transfer within the aquatic environment may still occur with secondary predation, or in predators with different feeding strategies