New Developments in Water Efficiency     

Tony T. Gregg Amanda Dewees Drema Gross Bill Hoffman Dan Strub Matt Watson 《中国海洋大学学报(英文版)》2006,5(4):375-380

1Water LossInitiativesUnaccounted-for water(or unbilled water)has beenreceiving newscrutiny at both the state and nationallevels.For years,water conservationeffortsin Europehave emphasized reduction in water loss to a muchgreater extent thaninthe United S…  相似文献   

The diameter of the sun at decameter wavelengths     

T. E. Gergely  B. D. Gross  M. R. Kundu 《Solar physics》1985,99(1-2):323-331

Using observations obtained with the Clark Lake radioheliograph we determined the diameter of the Sun in the decameter wavelength range. Both equatorial and polar diameters increase with decreasing frequency, as D=Af . The eccentricity of the brightness distribution appears to remain constant in the frequency range (30–74 MHz) in good agreement with the optical results in a corresponding height range. The smaller size of the polar diameter is attributed to coronal holes covering the poles during the period of our observations, while streamers were observed at the equator most of the time.  相似文献   

Multi-reference evaluation of uncertainty in earth orientation parameter measurements     

T. M. Chin  R. S. Gross  J. O. Dickey 《Journal of Geodesy》2005,79(1-3):24-32

Uncertainties in polar motion and length-of-day measurements are evaluated empirically using several data series from the space-geodetic techniques of the global positioning system (GPS), satellite laser ranging (SLR), and very long baseline interferometry (VLBI) during 1997–2002. In the evaluation procedure employed here, known as the three-corner hat (TCH) technique, the signal common to each series is eliminated by forming pair-wise differences between the series, thus requiring no assumed values for the “truth” signal. From the variances of the differenced series, the uncertainty of each series can be recovered when reasonable assumptions are made about the correlations between the series. In order to form the pair-wise differences, the series data must be given at the same epoch. All measurement data sets studied here were sampled at noon (UTC); except for the VLBI series, whose data are interpolated to noon and whose UT1 values are also numerically differentiated to obtain LOD. The numerical error introduced to the VLBI values by the interpolation and differentiation is shown to be comparable in magnitude to the values determined by the TCH method for the uncertainties of the VLBI series. The TCH estimates for the VLBI series are corrupted by such numerical errors mostly as a result of the relatively large data intervals. Of the remaining data sets studied here, it is found that the IGS Final combined series has the smallest polar motion and length-of-day uncertainties.  相似文献   

Erratum to: “Normal fault growth in layered rocks at Split Mountain, Utah: influence of mechanical stratigraphy on dip linkage, fault restriction and fault scaling”: [Journal of Structural Geology 24 (2002) 1413–1429]     

Scott J. Wilkins  Michael R. Gross 《Journal of Structural Geology》2002,24(12):1413

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Kinematics of throughgoing fractures in jointed rocks     

Martin D. Finn  Michael R. Gross  Yehuda Eyal  Grenville Draper 《Tectonophysics》2003,376(3-4):151-166

Throughgoing fractures play a major role in subsurface fluid flow yet the kinematics of their formation, which directly impact rock flow properties, are often difficult to establish. We investigate throughgoing fractures in the Monterey Formation of California that developed by the coalescence of pre-existing joints. At Lompoc Landing, throughgoing fractures fall into three main groups: linked, linked with aperture, and breccia zones. The segmented nature of their walls provides numerous piercing points to firmly establish the sense of displacement. Analysis of displacement vectors derived from piercing points demonstrates that the NW–SE trending throughgoing fractures, often interpreted as strike–slip faults, are in fact extensional structures in origin. We suggest that this method may be applied to throughgoing fractures that form by the same mechanism in other geologic settings. Establishing kinematics of throughgoing fractures will lead to a better understanding of their contribution to subsurface fluid flow.  相似文献   

Characterization of matrix material in Northwest Africa 5343: Weathering and thermal metamorphism of the least equilibrated CK chondrite     

Tasha L. Dunn  Oriana K. Battifarano  Juliane Gross  Emma J. O'Hara 《Meteoritics & planetary science》2018,53(10):2165-2180

Based on the chemical heterogeneity of chondrule and matrix olivine, Northwest Africa (NWA) 5343 is the least metamorphosed CK chondrite reported so far. To better constrain the lower limit of metamorphism in the CK chondrites, we performed a detailed analysis of matrix material in NWA 5343, including characterization of the texture and bulk composition and analyses of individual silicate minerals. Results suggest that NWA 5343 is petrologic type 3.6 or 3.7. Although silicate minerals in the matrix seem to be equilibrated to roughly the same extent throughout the sample, there are recognizable differences in grain size and shape. These textural differences may be the result of transient heating events during impacts, which would be likely on the CK chondrite parent body. The difference between the extent of chemical equilibration and texture may also suggest that grain size and shape are still sensitive to metamorphism at petrologic subtypes where silicate mineral equilibration is nearly complete (e.g., >3.7). Carbonate material present in NWA 5343 is a product of terrestrial weathering; however, infiltration of a Ca-bearing fluid did not influence the composition of silicate minerals in the matrix. To evaluate the possibility of a continuous metamorphic sequence between the CV and CK chondrites, the bulk matrix composition of NWA 5343 is compared to the CV_red chondrite, Vigarano. Although the matrix composition of NWA 5343 could be derived by secondary processing of a Vigarano-like precursor, porosity and texture of matrix olivine in NWA 5343 are hard to reconcile with a continuous metamorphic sequence.  相似文献   

Changes in global gravitational energy induced by earthquakes   总被引：1，自引：0，他引：1  

Benjamin Fong Chao  Richard S. Gross  Da-Nan Dong 《Geophysical Journal International》1995,122(3):784-789

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World Data Center-A for Paleoclimatology at the NOAA Paleoclimatology Program,Boulder, CO     

Robert S. Webb  Jonathan T. Overpeck  David M. Anderson  Bruce A. Bauer  Mildred K. England  Wendy S. Gross  E. Ann Meyers  Michael M. Worobec 《Journal of Paleolimnology》1993,9(1):69-75

Conclusion The World Data Center-A for Paleoclimatology, located in the NOAA/NGDC Paleoclimatology Program, is committed to providing the scientific community with easy access to all paleoenvironmental data. Efforts to make archived data readily available include international coordination of data acquisition, management, and distribution, sponsoring workshops and data cooperatives to facilitate the compilation of important data sets, development of a browse and visualization software package (PaleoVu), and dispersal of archived data on magnetic media or over ANONYMOUS FTP/INTERNET. The program publishes a semi-annual newsletter that highlights latest developments and accomplishments in the area of paleoenvironmental data for global change research. Contributions to the newsletter are welcome from researchers describing their efforts to coordinate the free flow of paleoclimate data throughout the international scientific community.For information on the program or to be added to the mailing list contact Mrs Mildred England (phone: 303-497-6227; Fax: 303 497-6513; e-mail: MKE@mail.ngdc.noaa.gov), NOAA National Geophysical Data Center, Paleoclimatology Program/World Data Center-A for Paleoclimatology, 325 Broadway, E/GC Boulder, CO 80303 USA  相似文献   

Numerical studies on cold fronts Part II: Orographic effects on gravity flows     

I. Bischoff-Gauss  G. Gross  F. Wippermann 《Meteorology and Atmospheric Physics》1989,40(4):159-169

Summary A two-dimensional nonhydrostatic numerical model was used to investigate the behaviour of a cold air gravity current, moving along complex terrain. It is found, that the model with a high horizontal and vertical resolution and with a closure scheme, using the turbulent kinetic energy, is suitable to simulate currents, which have the main features of those found in laboratory experiments.Simulations are presented for different orographic structures (mountain and valley), for varying thermal stratification of the environmental atmosphere (neutral, stable and stable with an elevated inversion) and for different heights of the cold air reservoir.The major effect of a hill on the advance of a gravity current is a reduction of the front speed upstream as well as (even stronger) downstream of the obstacle, where the amount of this decrease depends on thermal stratification. Near surface blocking of the air flow on the windward side occurs for all simulations. However, for small depths of the oncoming cold air, the current cannot surmount the hill and remains on the lee side.With 11 Figures  相似文献   

Zum Umweltverhalten von Fluortensiden Teil 1: Prüfung auf Aquatoxizität     

D. Prescher  U. Gross  J. Wotzka  M. Tscheu-Schlüter  W. Starke 《洁净——土壤、空气、水》1984,12(6):595-600

Poecilia reticulata PETERS (guppy) and the green alga Monoraphidium griffithii were used for testing of different fluorotensides. After the representation of the methods of investigation and the definition of criteria of toxicity the obtained results of investigation are discussed. In general, the toxicity of the four investigated fluorotensides to algae was lower than to fish. The anionic fluorotenside CF₃—(CF₂)n—CFH—COONa was an exception. In tables and diagrams the results are summarized. Finally, for the condition of the receiving-water biocenosis class “2” the respective still permissible matter concentrations are proposed. They vary between 0.05 and 0.2 mg/1.  相似文献