A method for determining the residual meteoritical mass in the Barringer Meteor Crater     

Henry L. Crowson 《Pure and Applied Geophysics》1971,85(1):38-68

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Effect of some co-dissolved inorganic groups on the photodecomposition of aqueous nitrates     

Enrico G. Gori  Henry M. Papée 《Pure and Applied Geophysics》1969,77(1):201-206

Summary The rate of nitrite formation, in UV-irradiated aqueous solutions of alkali metals, is found to depend on co-dissolved chemical compounds and on their reactivities. The effect of some common and simple components of the atmospheric aerosol is investigated in the laboratory.  相似文献   

Hydrofracture mechanisms in rock during pressure grouting     

H. Y. Wong  I. W. Farmer 《Rock Mechanics and Rock Engineering》1973,5(1):21-41

Summary Hydrofracture Mechanisms in Rock During Pressure Grouting. The paper examines the basic meachnisms controlling the initiation of fractures in rocks and layered soils during pressure grouting, and their subsequent propagation into the ground mass. Previous analyses of fracture initiation have tended to concentrate on simplified models in which the ground is treated as an impervious elastic or Mohr-Coulomb continuum. The present method allows for the porous or fissured nature of the ground by considering the effect of seepage forces induced by the pore pressure gradient. The effect is quantified by use of a parameterN such that the ratio of fluid force used in expanding the injection hole, to that used in forcing fluid through void spaces, isN to (1—N).Analysis of hydrofracture propagation is based on stress analysis of a borehole in an elastic continuum, the propagating fracture zone around the borehole being represented as a non-elastic material governed by the Mohr-Coulomb failure criterion. This is supplemented by an energy approach which equates the energy supplied to the ground from the injection pump, with the energy stored in the ground and the energy necessary to fracture it.

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Zusammenfassung Brucherscheinungen im Fels bei Verprearbeiten. In der Arbeit wird der grundlegende Mechanismus untersucht, welcher bei Verpreßarbeiten in Fels und geschichtetem Boden zur Einleitung und Ausbreitung von Brüchen führt. Frühere Untersuchungen des Bruchbeginns stützten sich im wesentlichen auf vereinfachte Modelle, in denen der Untergrund als undurchlässiges Kontinuum angesehen wird, das entweder elastisch ist oder der Mohr-Coulombschen Bruchbedingung genügt. Die neue Methode berücksichtigt dagegen eine Porosität oder Klüftung des Untergrundes durch Ansatz der vom strömenden Medium auf das Gebirge ausgeübten Belastung. Diese Belastung wird aufgeteilt in einen Druckverlust an der Bohrlochwand (gleich ParameterN mal Verpreßdruck) und die entsprechende, über den gesamten durchströmten Bereich verteilte Belastung.Die Untersuchung der Bruchausbreitung geht von der Spannungsermittlung um ein Bohrloch in einem elastischen Kontinuum aus, wobei in der sich ausbreitenden Bruchzone um das Bohrloch herum nichtelastisches Material angenommen wird, das dem Mohr-Coulombschen Bruchkriterium genügt. Zur Ergänzung dient eine Energie-Betrachtung, bei der die von der Injektionspumpe abgegebene Energie gleichgesetzt wird der im Untergrund gespeicherten Energie und der aufgewendeten Brucharbeit.

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Résumé Les mécanismes de la fracturation hydraulique dans les roches pendant les injections sous pression. Le mémoire examine les mécanismes fondamentaux qui gouvernent l'initiation des ruptures dans les roches et les sols stratifiés, au cours des injections et leur propagation dans les massifs. Les analyses antérieures de l'initiation de la rupture, se sont concentrées sur des modèles simplifiés où l'on considérait la roche comme un milieu élastique et imperméable, ou comme un milieu de Mohr-Coulomb. La présente méthode admet que le massif est poreux ou fissuré, en considérant l'action des forces de percolation engendrées par le gradient de pression interstitielle. Cette action est quantifiée par un paramètreN, tel que le rapport de la force du liquide employée à dilater le forage d'injection, à celle employée pour forcer le coulis à travers les vides soitN/(1—N). L'analyse de la propagation des ruptures se base sur l'analyse des contraintes autour d'un forage dans un milieu élastique, alors que la zone de la rupture qui se propage autour du forage est représentée par un milieu non-élastique admettant le critère de rupture de Mohr-Coulomb. Cette analyse est complétée par une approche énergétique, où l'énergie qui est fournie au massif par la pompe d'injection est égalée à l'énergie emmagasinée dans la roche et à l'énergie de rupture.

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Nomenclature A area of new cracks created per unit volume of time t - E total work done by injection fluid - E _i irrecoverable component of energy - E _{i c} work done in fracturing rock or soil - E _{i l} work done to overcome various frictional forces in grouting system - E _{i p} work done to cause plastic deformation of fractured zone - E _{i s} work done to overcome shear strength of fluid during flow - E _{i v} work done to overcome frictional drag between fluid and rock in soil surfaces during flow - E _r recoverable component of energy - E _{r f} elastic strain energy stored in fluid - E _{r s} elastic strain energy stored in rock or soil - h height of overburden - i j 1, 2, 3 - K ₀ coefficient of horizontal earth pressure - k permeability of ground to grout - L length of cylindrical grout source - n rock or soil porosity - p average fluid pressure between timet and (t + t) - p ₀ injection pressure - R radius of grout front - r radial distance from borehole axis - r ₀ radius of borehole - r ₁ radius of fractured zone - S specific surface area of rock or soil - S _T tensile strength of rock or soil - t time - u grout seepage velocity - V volume of grout injected - v volumetric strain - specific surface energy of rock - bulk density of rock or soil - _{i j} ^e elastic strain increment tensor - _{i j} plastic strain increment tensor - v Poisson's ratio - _{i j} average stress tensor in the ground during timet and (t + t) - _R , _T, _Z radial, tangential and vertical stresses induced by grouting - _r , _t , _z radial, tangential and vertical stress around borehole before grouting - grout shear strength - angle of internal friction of rock or soil With 7 Figures  相似文献   

The surface wind over an upwelling area near Pisco,Peru     

Wayne V. Burt  David B. Enfield  Robert L. Smith  Henry Crew 《Boundary-Layer Meteorology》1973,3(3):385-391

Harmonic analysis of longshore and onshore components of surface winds over an upwelling area off the coast of Peru shows regular, nearly sinusoidal, diurnal variations in both velocity components. Spectral analysis of wind speed also indicates strong diurnal variations in kinetic energy. The data are compatible with a recent model of coastal winds proposed by Lettau and Lettau.  相似文献   

Lake Kivu: structure,chemistry and biology of an East African rift lake     

Egon T. Degens  Richard P. von Herzen  How-Kin Wong  Werner G. Deuser  Holger W. Jannasch 《International Journal of Earth Sciences》1973,62(1):245-277

Geophysical, geochemical and biological data are integrated to unravel the origin and evolution of an unusual rift lake. The northern basin of Lake Kivu contains about 0.5 km of sediments which overlie a basement believed to be crystalline rocks of Precambrian age. Volcanic rocks at the northern end of the lake have created large magnetic anomalies of up to 300. Heat flow varies from 0.4 to 4 hfu. The extreme variability may be due in part to sedimentation or recent changes in the temperature of the bottom water. Sharp boundaries in the vertical temperature and salinity structure of the water across the lake can best be explained as separate convecting layers. Such convecting cells are the result of the increase in both temperature and salinity with depth.Concentrations of the major dissolved gases in the deep water, CO₂ and CH₄, approach saturation but do not exceed it at any depth. The salts are supplied mainly by hydrothermal discharges at the bottom of the lake which we calculate to have a salinity of 4 which is about 60% higher than the salinity of the bottom water. The annual discharge at the present time is about 0.5 km³. Zinc anomalies in the water are explained by the accumulation of sphalerite-containing globules at certain depths.Stratigraphic correlation of sediments is possible across the entire lake, based on physical, geochemical and paleontological criteria. Sedimentation rates are of the order of 30 cm/1000 years implying a Pliocene age for the deepest part of the lake. Periods of hydrothermal activities and heightened volcanism, as recorded in the sediments, appear to have coincided with pluvial times.Enrichment of the surface waters of Lake Kivu by nutrients has led to explosive speciation in the diatom genusNitzschia. Several new types of methane oxidizing and-producing bacteria were isolated. Bacterial degradation of recent plankton appears insufficient to explain the amount of methane in the lake, and some of it is derived diagenetically.

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Zusammenfassung Geophysikalische, geochemische und biologische Daten werden vorgelegt und miteinander in Beziehung gebracht, um einen besseren Einblick in Entstehung und Evolution eines ungewöhnlichen Sees zu gewinnen. Das nördliche Becken des Kivu-Sees enthält Sedimente von etwa 0,5 km Mächtigkeit, die dem präkambrischen kristallinen Grundgebirge überlagert sind. Die im Norden des Sees vorliegenden vulkanischen Gesteine erklären die hohen magnetischen Anomalien, die bis zu 300 betragen. Der Wärmefluß schwankt zwischen 0,4 und 4 cal/cm²/sec. Diese Schwankungsbreite erklärt sich zum Teil aus den Sedimentationsverhältnissen oder den lokalen Temperaturveränderungen im Tiefenwasser. Scharfe Grenzflächen in der vertikalen Temperatur- und Salinitätsstruktur des Wassers über den Gesamtsee sind das Ergebnis von Konvektion, die zu übereinanderliegenden Konvektionszellen führt, in denen jeweils Temperatur und Salinität konstant sind. Die Bildung, Anzahl und Stabilität solcher Zellen hängt von dem Verhältnis der durch Temperatur und Salzgehalt hervorgerufenen Dichteveränderungen ab.Die Konzentrationen der im Tiefenwasser gelösten Gase, d. h. von Kohlendioxyd und Methan, liegen für alle Tiefen unterhalb der Löslichkeit. Die vorliegenden Salze entstammen weitgehend hydrothermalen Lösungen, die dem Seeboden entweichen und deren Salinität etwa 4 beträgt; der Vergleichswert für das Tiefenwasser beträgt 2,5 Diese hydrothermalen Ausschüttungen haben eine Größe von etwa 0,5 km³ pro Jahr, was etwa ein Tausendstel des Gesamtseevolumens ausmacht. Zinkanomalien im Wasser sind ebenfalls hydrothermal bedingt.Physikalische, geochemische und paläontologische Indikatoren erlauben eine stratigraphische Korrelation aller Sedimentkerne. Die Sedimentationsraten liegen bei 30 cm/ 1000 Jahren, und ein pliozänes Alter errechnet sich daraus für das tiefe nördliche Becken. Perioden hydrothermaler Aktivitäten und verstärkter vulkanischer Tätigkeit, die sich in den Sedimenten nachweisen lassen, scheinen mit Pluvialzeiten zu koinzidieren.Die Anreicherung der Oberflächenwässer vom Kivusee durch Mineralstoffe führte zu einer explosionsartigen Spezisierung in der GattungNitzschia. Verschiedene neue Arten von Methan-oxidierenden und -produzierenden Bakterien wurden isoliert. Das Auftreten von Methan ist zum Teil bakteriell und zum Teil diagenetisch bedingt.

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Résumé Des données géophysiques, géochimiques et biologiques sont présentées et collationnées pour donner une vue meilleure sur l'origine et l'évolution d'un lac particulier de la «Rift valley». La baie septentrionale du lac Kivu contient environ 500 mètres de sédiments qui recouvrent le socle cristallin d'âge précambrien. Des épanchements volcaniques au Nord du lac expliquent les fortes anomalies magnétiques qui atteignent 300. Les valeurs du flux thermique varient entre 0.4 et 4 cal/cm²/sec. Cette importante variation s'explique en partie par la sédimentation ou par des changements locaux de la température de l'eau de fond. Des surfaces-limites brusques dans la structure verticale de la répartition de la température et de la salinité de l'eau dans l'étendue du lac sont dûs à la convection; celle-ci conduit à la superposition de cellules de convection dans lesquelles la température et la salinité sont constantes. La formation, le nombre et la stabilité de telles cellules dépendent du rapport des variations de densité dues à la température et à la teneur en sels.Les concentrations des gaz dissouts dans l'eau profonde, en l'occurrence CO₂ et CH₄, sont, à toute profondeur, inférieures à la saturation. Les sels minéraux proviennent surtout de solutions hydrothermales qui émanent du fond du lac, et dont la salinité est voisine de 4; la valeur comparative pour l'eau profonde est de 2,5. L'apport annuel de ces sources est de l'ordre de 0,5 km³, soit 1/1000 du volume total du lac. Les teneurs anormales en Zn sont dues également à ce caractère hydrothermal.Des données physiques, géochemiques et paléontologiques permettent la corrélation stratigraphique des sédiments. Les vitesses de sédimentation sont de l'ordre de 30 cm/1000 ans, donnant ainsi un âge pliocène pour la partie profonde de la baie septentrionale. Les périodes d'activité hydrothermale et de renforcement de la vulcanicité qui se manifestent dans les sédiments, semblent coïncider avec les périodes pluviales.L'enrichissement des eaux de surface du lac Kivu en substances minérales a entraîné un développement explosif des diatomées, en particulier du genreNitzchia. Différentes espèces nouvelles de bactéries oxydant et produisant CH₄ ont été isolées. La présence de méthane est due en partie à la destruction du plancton par les bactéries et en partie à une transformation diagénétique.

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, , . Kivu 0,5 , . , 300 . 0,4 4 (²) . , . . , , , . , . . _{2 4} . , 4%. 2,5%. 0,5 ³, , 1/1000 . ., . 30 /1000 , . . . , , , . Kivu Nitzschia. , . , — .

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Luna 20: mineralogy and petrology of fragments less than 125 μm size     

Henry O.A. Meyer 《Geochimica et cosmochimica acta》1973,37(4):943-952

Two milligrams of less than 125 μm size particles from the Luna 20 soil sample (22001,17) have been examined. The results of the mineral identification and analysis verify earlier assumptions that the nature of the lunar highlands is predominantly anorthositic in composition. The presence of highly magnesian clinopyroxene, orthopyroxene and olivine suggests crystallization of Highland rocks in an ultrabasic environment. No fragments were observed that could be unequivocally assigned to mare basalt types.  相似文献   

Comet searches during four major eclipses     

Henry C. Courten 《Solar physics》1971,21(2):495-495

Photographic observations made during the solar eclipses of 1963, 1966, 1968, and 1970 indicate the presence of previously unidentified celestial objects in the near-angular vicinity of the Sun. Observational data and equipment are described. Possible origins of the objects are enumerated, as well as suggested future experiments to confirm the results.  相似文献   

Effect of size, tissue parts and location on six biochemical markers in the green-lipped mussel, Perna viridis     

Lau PS  Wong HL 《Marine pollution bulletin》2003,46(12):1563-1572

The effect of size and tissue parts as well as site locations on a suite of six anti-oxidative biochemical markers, viz. the enzyme degrading neural transmitters acetylcholinesterase (AChE), the Phase II transforming enzyme glutathione-S-transferase (GST), the anti-oxidative enzymes superoxide dismutase (SOD) and catalase (CAT), the lipid metabolite malondialdehyde (MDA) and the ratio of CAT/MDA, in the bivalve mollusc, Perna viridis, was studied. Field mussels were collected from the piers of University of Science and Technology (UST), Pak Sha Wan or Hebe Haven (PS) and Sai Kung (SK) in Port Shelter, Hong Kong. Statistically, ANOVA showed that the activity of all six biochemical markers were generally tissue dependent, size independent and location dependent. Tukey multi comparison test indicated that the biochemical activities fell into two groups, with SK the highest activity group in most cases. The significance of these findings in relation to long-term coastal water biomonitoring is discussed.  相似文献   

Paralytic shellfish toxins in green-lipped mussels,Perna viridis,in Hong Kong     

Mak KC  Li AM  Hsieh DP  Wong PS  Lam MH  Wu RS  Richardson BJ  Lam PK 《Marine pollution bulletin》2003,46(2):258-263

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Influence of uncertain boundary conditions and model structure on flood inundation predictions   总被引：2，自引：0，他引：2  

Florian Pappenberger  Patrick Matgen  Keith J. Beven  Jean-Baptiste Henry  Laurent Pfister  Paul Fraipont de 《Advances in water resources》2006

In this study, the GLUE methodology is applied to establish the sensitivity of flood inundation predictions to uncertainty of the upstream boundary condition and bridges within the modelled region. An understanding of such uncertainties is essential to improve flood forecasting and floodplain mapping. The model has been evaluated on a large data set. This paper shows uncertainty of the upstream boundary can have significant impact on the model results, exceeding the importance of model parameter uncertainty in some areas. However, this depends on the hydraulic conditions in the reach e.g. internal boundary conditions and, for example, the amount of backwater within the modelled region. The type of bridge implementation can have local effects, which is strongly influenced by the bridge geometry (in this case the area of the culvert). However, the type of bridge will not merely influence the model performance within the region of the structure, but also other evaluation criteria such as the travel time. This also highlights the difficulties in establishing which parameters have to be more closely examined in order to achieve better fits. In this study no parameter set or model implementation that fulfils all evaluation criteria could be established. We propose four different approaches to this problem: closer investigation of anomalies; introduction of local parameters; increasing the size of acceptable error bounds; and resorting to local model evaluation. Moreover, we show that it can be advantageous to decouple the classification into behavioural and non-behavioural model data/parameter sets from the calculation of uncertainty bounds.  相似文献