Low Energy Transfer to the Moon

In 1991, the Japanese Hiten mission used a low energy transfer with a ballistic capture at the Moon which required less Vthan a standard Hohmann transfer. In this paper, we apply the dynamical systems techniques developed in our earlier work to reproduce systematically a Hiten-like mission. We approximate the Sun–Earth–Moon-spacecraft 4-body system as two 3-body systems. Using the invariant manifold structures of the Lagrange points of the 3-body systems, we are able to construct low energy transfer trajectories from the Earth which execute ballistic capture at the Moon. The techniques used in the design and construction of this trajectory may be applied in many situations.     

Climate and human health: synthesizing environmental complexity and uncertainty

Broad relationships between weather and human health have long been recognized, and there is currently a large body of research examining the impacts of climate change on human health. Much of the literature in this area examines climate–health relationships at global or regional levels, incorporating mostly generalized responses of pathogens and vectors to broad changes in climate. Far less research has been done to understand the direct and indirect climate-mediated processes involved at finer scales. Thus, some studies simplify the role of climate and may over- or under-estimate the potential response, while others have begun to highlight the subtle and complex role for climate that is contingent on other relevant processes occurring in natural and social environments. These fundamental processes need to be understood to determine the effects of past, current and future climate variation and change on human health. We summarize the principal climate variables and climate-dependent processes that are believed to impact human health across a representative set of diseases, along with key uncertainties in these relationships.     

Glycol Ethers As Groundwater Contaminants

Ether derivatives of dihydroxy alcohols, which are formed from ethylene or propylene, comprise an important group of groundwater contaminants known as glycol ethers. Compounds in this group are used as solvents, cleaning agents, and emulsifiers in many chemical products and manufacturing operations. Glycol ethers have been associated with a variety of toxic effects, and some compounds in the group are relatively potent teratogens. The limited information available suggests that glycol ethers are contaminants in groundwater, especially in anaerobic plumes emanating from disposal of mixed industrial and household waste. Most methods used to analyze groundwater samples cannot adequately detect 7g/’ (ppb) concentrations of glycol ethers, and the existing methods perform worst for the most widely used and toxic species. A new method capable of analyzing 7g/’ concentrations of glycol ethers was recently developed, and its use is recommended for groundwater samples where glycol ethers are likely to be present. Résumé. Les éthers glycol, polluants des eaux souterraines. Les dérivés d'éther de dihydroxy-alcool, formés à partir de l'éthylène ou du propylène, constituent un important groupe de polluants des eaux souterraines connus sous le nom d'éthers glycol. Les composés de ce groupe sont utilisés comme solvants, comme agents de nettoyage et comme émulsifiants dans de nombreux produits chimiques et dans de nombreux processus de fabrication. Des effets toxiques variés ont été attribués aux éthers glycol et certains des composés sont des agents tératogènes relativement puissants. Les données disponibles, qui sont limitées, indiquent que les éthers glycol sont des polluants communs dans les eaux souterraines, particulièrement dans les panaches anaéorobies émis par les décharges mixtes de déchets industriels et domestiques. La plupart des méthodes d'analyse d'échantillons d'eau souterraine ne sont pas capables de détecter convenablement des concentrations en éthers glycol de l'ordre du 7g/l (ppb); les méthodes actuelles sont médiocres pour doser les espèces toxiques les plus courantes. Une nouvelle méthode permettant de doser des concentrations en éthers glycol de l'ordre du 7 g/l a été récemment mise au point; son utilisation est préconisée pour les échantillons d'eau souterraine contenant des éthers glycol.     

Endmember graphics

Thek points inp-space corresponding to a specified set ofk (k<p) linearly independent endmember estimates associated with ap-variate (n×p) compositional datasetX, define the vertices of a (k?1) dimensional simplexH. Then estimated mixtures which together account for the systematic variation in the datasetX, are each convex combinations of thek fixed endmember estimates. Accordingly, then-points inp-space which represent these mixtures must be interior points of the simplexH. The purpose of this paper is to describe a simple graphical procedure for examining the positions of the estimated mixtures relative tok=3 or 4 putative endmembers, and for assessing their compliance or otherwise with the convexity constraints. Since the mixture coefficients must be estimated first in order to obtain the mixture estimates, the paper begins with a review of the least-squares partitioning procedure.     

Equilibrium coexistence of three amphiboles

Electron probe and wet chemical analyses of amphibole pairs from the sillimanite zone of central Massachusetts and adjacent New Hampshire indicated that for a particular metamorphic grade there should be a restricted composition range in which three amphiboles can coexist stably. An unequivocal example of such an equilibrium three amphibole rock has been found in the sillimanite-orthoclase zone. It contains a colorless primitive clinoamphibole, space group P2₁/m, optically and chemically like cummingtonite with blue-green hornblende exsolution lamellae on (100) and (¯101) of the host; blue-green hornblende, space group C2/m, with primitive cummingtonite exsolution lamellae on (100) and (¯101) of the host; and pale pinkish tan anthophyllite, space group Pnma, that is free of visible exsolution lamellae but is a submicroscopic intergrowth of two orthorhombic amphiboles. Mutual contacts and coarse, oriented intergrowths of two and three host amphiboles indicate the three grew as an equilibrium assemblage prior to exsolution. Electron probe analyses at mutual three-amphibole contacts showed little variation in the composition of each amphibole. Analyses believed to represent most closely the primary amphibole compositions gave atomic proportions on the basis of 23 oxygens per formula unit as follows: for primitive cummingtonite (Na_0.02Ca_0.21 ^– Mn_0.06Fe²⁺ _2.28Mg_4.12Al_0.28) (Al_0.17Si_7.83), for hornblende (Na_0.35Ca_1.56Mn_0.02Fe_1.71Mg_2.85Al_0.92) (Al_1.37Si_6.63), and for anthophyllite (Na_0.10Ca_0.06Mn_0.06Fe_2.25Mg_4.11Al_0.47) (Al_0.47Si_7.53). The reflections violating C-symmetry, on X-ray single crystal photographs of the primitive cummingtonite, are weak and diffuse, and suggest a partial inversion from a C-centered to a primitive clinoamphibole. Single crystal photographs of the anthophyllite show split reflections indicating it is an intergrowth of about 80% anthophyllite and about 20% gedrite which differ in their b crystallographic dimensions. Split reflections are characteristic of all analyzed orthorhombic amphiboles so far examined from Massachusetts and New Hampshire except the most aluminous gedrites, and the relative intensity of the gedrite reflections is roughly proportional to the degree of Na and Al substitution. Thin sections of a few of these anthophyllite specimens show lamellae parallel to (010) that are just resolved with a high power objective.Publication approved by the Director, U.S. Geological Survey.     

Tektites: A post-Apollo view

Prior to the receipt of the lunar samples, it was the scientific consensus that tektites were melted and splashed material formed during large cometary or meteorite impact events. Whether the impact took place on the Earth or the Moon was the topic of a long-standing scientific debate, which raged with particular intensity during the decade previous to the lunar landings.Four definite and separate tektite-strewn fields are known: bediasites (North America, 34 m.y.); moldavites (Czechoslovakia, 14 m.y.); Ivory Coast (1.3 m.y.); and Southeast Asian and Australian fields (0.7 m.y.). A fifth possible occurrence, of high-Na australites, possibly 3–4 m.y. old, remains to be substantiated. The age of infall of the australites is not agreed upon. Radiometric and fission track dates agree with the magnetic stratigraphy for deep-sea core microtektite occurrences at about 0.7 m.y. Terrestrial stratigraphic evidence favours a recent (30,000 years) date.The chemistry of tektites appears to reflect that of the parent material, and losses during fusion appear to be restricted to elements and compounds more volatile than cesium. Terrestrial impact glasses provide small-scale analogues of tektite-forming events, and indicate that only the most volatile components are lost during fusion.The Apollo lunar missions provide critical evidence which refutes the hypothesis of lunar origin of tektites. Tektite chemistry is totally distinct from that observed in lunar maria basalts. These possess Cr contents which are two orders of magnitude higher than tektites, distinctive REE patterns with large Eu depletions, high Fe and low SiO₂ contents, low K/U ratios and many other diagnostic features, none of which are observed in the chemistry of tektites. The lunar uplands compositions, as shown by Apollo 14, 15 and 16 samples and the μ-ray and XRF orbiter data, are high-Al, low-SiO₂ compositions totally dissimilar to those of tektites. The composition of lunar rock 12013 shows typical lunar features and is distinct from that of tektites. The small amounts of lunar K-rich granitic material found in the soils have K/Mg and K/Na ratios 10–50 times those of tektites.The ages of the lunar maria (3.2–3.8 aeons) and uplands (> 4.0 aeons) are an order of magnitude older than the parent material of the Southeast Asian and Australian tektites, which yield Rb-Sr isochrons indicating ages of the order of 100–300 m.y. The lunar lead isotopic compositions are highly radiogenic whereas tektites have terrestrial Pb isotopic ratios. Lunar δ¹⁸ O values are low (< 7 per mil) compared with values of +9.6 to +11.5 per mil for tektites. In summary, a lunar impact origin for tektites is not compatible with the chemistry, age or isotopic composition of the lunar samples. A lunar volcanic origin, recently revived by O'Keefe (1970) encounters most of the same problems. Recent lunar volcanism (< 50 m.y.), if the source of tektites, should contribute tektite glass to the upper layers of the regolith. None has been found. The presence of meteoritic components in tektites, and the high pressure phase coesite, are more readily interpreted as evidence of impact.The element abundances and inter-element variations in tektites do not resemble those in terrestrial igneous rocks, but show a close similarity to terrestrial sandstones. The composition of the Southeast Asian tektites, australites and moldavites resembles that of micaceous sandstones or subgreywackes, the Ivory Coast tektite composition is similar to that of greywacke, and the bediasite chemistry is analogous to that of arkose.No suitable terrestrial impact site has been identified for the bediasites, Southeast Asian tektites and australites. It is suggested that a search for the source of these latter strewnfields be made using satellite photographs to look for wide shallow craters produced by super-Tunguska type events on areas of Mesozoic sandstones. The moldavites were possibly formed during the Ries Crater event but, if so, the precise source of the material remains to be identified. The Ivory Coast tektites are linked by chemistry, isotope and age evidence to the Bosumtwi Crater, Ghana. The overall evidence now supports the origin of tektites by cometary (or meteorite) impact on terrestrial sedimentary rocks.     

Electricity consumption patterns within cities: application of a data-driven settlement characterization method

ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.     

Observations from space of the solar corona/inner zodical light

Observations, from the Apollo 16 Spacecraft, in lunar orbit, of the total radiance of the K + F corona, from 3 R to 55 R are presented and discussed.

The logarithmic slope of the K + F coronal radiance, in the region r > 20 R, is found to be n = 1.93, slightly less steep than previous determinations. The photometric axis of the radiance is found to be displaced 3 ± 1° north of the ecliptic, for the region r > 20 R, and this displacement is interpreted as an annual variation due to non-coincidence of the ecliptic and the symmetry axis of the zodiacal cloud.