Cs-135 - Ba-135: A new cosmochronometric constraint on the origin of the Earth and the astrophysical site of the origin of the solar system

It is argued that if Cs-135 was indeed present in the early solar system at the level inferred from evidence presented here, then two major conclusions follow. (1) A supernova contributed newly synthesized r-process matter into the protosolar reservoir within approx. 5 Ma of the Cs/Ba fractionation recorded in LEW 86010; (2) The strong Cs depletion in the bulk Earth reservoir (Cs-133/Ba-135 approx. 0.1) took place very early in solar system history. If this volatile loss was pre-accretionary, then the accretionary chronology of the Earth is not constrained. However, if it is a consequence of accretion, then the very tight time constraint of approx. less than 5 Ma (rel. to LEW 86010) is obtained for accretion of most of the Earth's mass

Nd-142/Nd-144 in SNCs and early differentiation of a heterogeneous Martian mantle

Sm/Nd correlated variations in Nd-142/Nd-144 have been observed for mineral phases of achondrites from decay of live Sm-146 in the early solar system. Crystallization ages of shergottites-nakhlites-Chassigny (SNC) meteorites are less than or = 1.3 Ga, so variations of Nd-142/Nd-144 among mineral phases of the SNC's are not expected. However, if SNC's were derived from source reservoirs of differing Sm/Nd ratios, established while Sm-146 was still alive, and which remained isolated except for magma extraction, then variations in Nd-142/Nd-144 would exist among individual SNC meteorites. Rb-Sr and U-Pb isotopic data for the shergottites imply differentiation of their parent planet approximately 4.6 Ga ago. The confirmation of the conclusion that the nakhlites and shergottites were derived from different source regions, and that, consequently, the shergottite parent body (SPB) mantle was heterogeneous is presented

Prospects for reduced energy transports: A preliminary analysis

The recent energy crisis and subsequent substantial increase in fuel prices have provided increased incentive to reduce the fuel consumption of civil transport aircraft. At the present time many changes in operational procedures have been introduced to decrease fuel consumption of the existing fleet. In the future, however, it may become desirable or even necessary to introduce new fuel-conservative aircraft designs. This paper reports the results of a preliminary study of new near-term fuel conservative aircraft. A parametric study was made to determine the effects of cruise Mach number and fuel cost on the optimum configuration characteristics and on economic performance. For each design, the wing geometry was optimized to give maximum return on investment at a particular fuel cost. Based on the results of the parametric study, a nominal reduced energy configuration was selected. Compared with existing transport designs, the reduced energy design has a higher aspect ratio wing with lower sweep, and cruises at a lower Mach number. It has about 30% less fuel consumption on a seat-mile basis

The AXAF technology program: The optical flats tests

The results of a technology program aimed at determining the limits of surface polishing for reflecting X-ray telescopes is presented. This program is part of the major task of developing the Advanced X-ray Astrophysical Facility (AXAF). By studying the optical properties of state-of-the-art polished flat surfaces, conclusions were drawn as to the potential capability of AXAF. Surface microtopography of the flats as well as their figure are studied by X-ray, visual, and mechanical techniques. These techniques and their results are described. The employed polishing techniques are more than adequate for the specifications of the AXAF mirrors

Disposal of Household Wastewater in Soils of High Stone Content (1981-1983)

Four experimental filter fields were constructed with built-in monitoring equipment in Nixa soils. These soils contain many chert fragments and a fragipan about 60 cm below the soil surface. The fragipan restricts downward movement of water and is the designlimitingfeature. The four filter fields were: 1. A standard filter field, 76 cm deep. The bottom of the trench was in the fragipan. 2. A modified standard filter field, 30 cm deep. The bottom of the trench was above the fragipan. 3. A modified pressure filter field, 40 cm deep. The bottom of the trench was above the fragipan. In addition, a pressure-distribution system was used to insure uniform distribution of effluent in the trench. Inadvertently, this field was installed in a different soil, and the results cannot be compared directly with the other three. 4. Another modified pressure filter field with the bottom of the trench only 6 cm below the soil surface. Observation of these systems confirms that placing filter fields higher in the soil above the hydraulically limiting horizon results in improved hydraulic performance. The presence of the fragipan amplified the adverse effects attributable to climatic stress. The seepage beds which are higher in the soil profile are able to handle the effluent load and climate load with less danger of surfacing

Analytical and experimental study of stratification and liquid-ullage coupling, 1 June 1964 - 31 May 1965

Closed-form solution for stratification of subcooled fluids in containers subjected to heating, and for liquid-ullage vapor couplin

LINEAR-PLATEAU REGRESSION ANALYSIS AND ITS APPLICATION TO SELENITE ADSORPTION RATE

Simple computational methods are presented which facilitate fitting regression models to response data exhibiting a plateau effect. The iterative statistical program (called PLATFOR) is written in FORTRAN (a SAS version is also available), and produces all relevant regression statistics, plots, and information on goodness of fit. The presented procedures are empirically valuable, since linear-plateau models have many useful applications in agriculture, especially in soil fertility and soil chemistry experiments. The technique was employed in an experiment designed to determine the effect of soil volcanic ash content on selenite adsorption. Ion chromatographic methods were used to investigate selenite adsorption in three acidic North Idaho surface soils of varying ash content. Equilibration periods of 0.5 to 12.0 hours were evaluated and the time required to reach maximum adsorption was determined using the PLATFOR program. It was concluded that both the rate and magnitude of selenite adsorption were influenced by soil volcanic ash content

Nd-142/Nd-144 in bulk planetary reservoirs, the problem of incomplete mixing of interstellar components and significance of very high precision Nd-145/Nd-144 measurements

Apart from the challenge of very high precision Nd-142/Nd-144 ratio measurement, accurate applications of the coupled Sm-(146,147)-Nd-(142,143) systematics in planetary differentiation studies require very precise knowledge of the present-day (post-Sm-146 decay) Nd-142/Nd-144 ratios of bulk planetary objects (BP). The coupled systematics yield model ages for the time of formation of Sm/Nd-fractionated reservoirs by differentiation of Sm/Nd-unfractionated bulk planetary reservoirs. Estimates of (Nd-142/Nd-144)(sub BP) and (Nd-143/Nd-144)(sub BP) therefore provide the critical baseline relative to which these model ages are referenced. In the Sm-147-Nd-143 systematics, Nd-143/Nd-144 variations are mostly large; therefore, small variations in initial Nd-143/Nd-144 ratios generally can be ignored. However, in the case of Sm-146-Nd-142, the range of Nd-142/Nd-144 divergence for differentiated planetary reservoirs is much smaller. Consequently Sm-(146,147)-Nd-(142,143) model ages are sensitive to small variations in bulk planetary Nd-142/Nd-144 (both present-day and initial). One major unanswered question is whether or not Nd shelf standards (CIT Nd beta/Ames metal, La Jolla, NASA-JSC/Ames metal) have Nd-142/Nd-144 identical to the bulk Earth or otherwise might record some degree of radiogenic evolution in an early-fractionated reservoir. Our discussions of earth Earth differentiation based on Nd-142/Nd-144 in Isua and Acasta samples have employed a working assumption: (Nd-142/Nd-144)(sub Nd beta) = (Nd-142/Nd-144)(sub Bulk Earth). This requires experimental justification and is apparently contradicted by chondrite Nd-142/Nd-144 measurements, which have been interpreted to indicate: (Nd-142/Nd-144)(sub JSC/Ames metal) = ((Nd-142/Nd-144)(sub CHUR) = 35 plus or minus 8 ppm). At present, interpretations of the early Earth and Moon hinge largely on this issue. Because Ba in bulk chondrite samples exhibit similar magnitude nuclear anomalies, attributable to incomplete mixing of interstellar components, a critical question is whether or not nuclear effects are also present in Nd-142/Nd-144, both in bulk chondrites and between planetary objects