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Inflow
Kinds of Inflow Terms modified by Inflow Selected AbstractsLINK BETWEEN DOMESTIC R&D AND INFLOW OF FDI: A GAME-THEORETIC ANALYSISPACIFIC ECONOMIC REVIEW, Issue 2 2008Hamid Beladi Further, the existing theoretical explanations of such empirical results appear to be inadequate. This study presents an alternative game-theoretic explanation for the observed correlations. The results show that the seemingly contradictory observed mixed correlations can be explained in an encompassing model in terms of the multinationals' competitive and interactive assessment of the efficiency and expenditure consequences that domestic R&D could generate for the undertaking domestic competitors. [source] Permeable and non-reflecting boundary conditions in SPHINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2009Martin Lastiwka Abstract Inflow and outflow boundary conditions are essential for the application of computational fluid dynamics to many engineering scenarios. In this paper we present a new boundary condition implementation that enables the simulation of flow through permeable boundaries in the Lagrangian mesh-free method, smoothed particle hydrodynamics (SPH). Each permeable boundary is associated with an inflow or outflow zone outside the domain, in which particles are created or removed as required. The analytic boundary condition is applied by prescribing the appropriate variables for particles in an inflow or outflow zone, and extrapolating other variables from within the domain. Characteristic-based non-reflecting boundary conditions, described in the literature for mesh-based methods, can be implemented within this framework. Results are presented for simple one-dimensional flows, quasi-one-dimensional compressible nozzle flow, and two-dimensional flow around a cylinder at Reynolds numbers of 40 and 100 and a Mach number of 0.1. These results establish the capability of SPH to model flows through open domains, opening a broad new class of applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] Climate variability in Malawi, part 2: sensitivity and prediction of lake levelsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 11 2002M. R. Jury Abstract Southern Africa has only a few large lakes, one of which is Lake Malawi. It forms part of the lower Zambezi catchment and the Great Rift Valley. The lake provides food, energy, transport and recreation to the local people. Inflow to the lake increases through summer (December to April) when the equatorial convection zone lies overhead. An analysis of lake levels in the period 1937,95 has been conducted and changes are related to variations in rainfall and atmospheric conditions. Interannual cycles in the time series are consistent with those found for Zambezi River streamflows, suggesting a degree of regional coherence. Years with high inflow are contrasted with mean conditions using the National Centres for Environmental Prediction reanalysis data for the period since 1958. Composite anomalies of wind fields for wet years reveal a zonal overturning circulation. Low (upper) level westerlies (easterlies) link with a sub-tropical trough in the Mozambique Channel to enhance regional convection and lake inflows. The results provide input to predictive models for Lake Malawi to plan better the management of water resources in this part of Africa. Copyright © 2002 Royal Meteorological Society. [source] Capital Inflows, Resource Reallocation and the Real Exchange Rate,INTERNATIONAL FINANCE, Issue 2 2008Emmanuel K. K. Lartey A large capital inflow to a developing economy can potentially cause a real exchange rate appreciation that is detrimental to the prospects of its tradable sector; a phenomenon known as the Dutch Disease. I analyse the effects of both the level and share of capital inflow on resource reallocation and real exchange rate movements in a small open economy. I find that there exists a trade-off between resource reallocation and the degree of real exchange rate appreciation. In particular, the less labour the tradable sector loses to the non-tradable sector, the greater is the real exchange rate appreciation. This result is driven by the share of investment accounted for by foreign capital, and suggests that an emerging market economy that adopts a production technique which utilizes a greater share of foreign capital relative to domestic capital will be more susceptible to the Dutch Disease following an increase in capital inflow. The results also imply that a policy designed to minimize real exchange rate appreciation during capital inflow episodes should encompass measures aimed at stabilizing prices of non-tradables. [source] Large Apical Muscular Ventricular Septal Defect: Asymptomatic due to Anomalous Muscle Bundles in the Right VentricleCONGENITAL HEART DISEASE, Issue 1 2007Anant Khositseth MD ABSTRACT This case report demonstrated an apical muscular ventricular septal defect (VSD) that was a large defect but behaved like a small defect because of the restrictive flow across the anomalous muscle bundles in the right ventricular (RV) apex. The anomalous muscle bundles separated the RV sinus into two parts: the RV apex connecting with the left ventricle through the apical muscular VSD on one side, and the rest of the RV sinus connecting with RV inflow and RV outflow on the other side. These findings explained why the 11-year-old girl in this study remained asymptomatic without evidence of volume load. Thus far, it was not necessary to close her defect because of the hemodynamic insignificance. [source] In Situ Urbanization in Rural China: Case Studies from Fujian ProvinceDEVELOPMENT AND CHANGE, Issue 2 2000Yu Zhu In most parts of the developing world, the urbanization process has been dominated by rural,urban migration and the growth of existing cities. However, case-studies in China's Fujian Province suggest that this process can also be achieved mainly by in situ transformation in rural areas. Such in situ transformation of rural areas has been driven mainly by two forces, the development of township and village enterprises (TVEs) and the inflow of foreign investment; and facilitated by the relevant policies adopted by the Chinese government since 1978. The former has been very effective in the transformation of rural employment structure, while the latter has brought many physical changes to the previously rural landscape. Being mutually complementary, these two ways of rural transformation have not only benefited and urbanized the rural areas, but kept many farmers in their hometowns, replacing the dominant role of rural,urban migration and the growth of existing cities in the urbanization process. [source] Effectiveness of grass strips in trapping suspended sediments from runoffEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2010Chengzhong Pan Abstract Little information is available concerning the performance of grass strips for erosion control from steep cropland. An experiment was conducted on 5-m-long grass strips with slopes of 3°,15° that were subjected to silt laden runoff and simulated rainfall, to investigate the sediment trapping processes. The grass strips had three treatments including intact grass control (C), no litter (dead grass material covering the soil surface was removed) (NL), and no litter or leaves (only 2,3,cm grass stems and roots were reserved) (NLL). Generally the grass strips had a high effectiveness in trapping sediment from steep cropland runoff. Sediment trapping efficiency (STE) decreased with increasing slope gradient, and even for a 15° slope, STE was still more than 40%. Most sediment deposited in the backwater region before each grass strips. The removal of grass litter or/and leaves had no significant influence on STE. The sediment median size (D50) in inflow was greater than that in outflow, and the difference (,D50) decreased with increasing slope. A positive power relationship between STE and ,D50 can be obtained. Grass strips were more effective in trapping sediments coarser than 10 or 25,µm, but sediments finer than 1,µm were more readily removed from runoff than particles in the range of 2 to approximately 10,µm. Grass litter had less influence on flow velocity than leaves because the deposited sediment partially covered the litter layer. Mean flow velocity and its standard deviation were negatively correlated with STE, and they can help make good estimation of STE. Results from this study should be useful in planting and managing forage grass to effectively conserve soil loss by runoff from steep slopes on the Loess Plateau of China. Copyright © 2010 John Wiley & Sons, Ltd. [source] Morphodynamics of the exit of a cutoff meander: experimental findings from field and laboratory studies,EARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2010J. Le Coz Abstract The morphological evolution of the entrances and exits of abandoned river channels governs their hydrological connectivity. The study focusses on flow and sediment dynamics in the exit of a cutoff meander where the downstream entrance is still connected to the main channel, but the upstream entrance is closed. Two similar field and laboratory cases were investigated using innovative velocimetry techniques (acoustic Doppler profiling, image analysis). Laboratory experiments were conducted with a mobile-bed physical model of the Morava River (Slovakia). Field measurements were performed in the exit of the Port-Galland cutoff meander, Ain River (France). Both cases yielded consistent and complementary results from which a generic scheme for flow patterns and morphological evolution was derived. A simple analogy with flows in rectangular side cavities was used to explain the recirculating flow patterns which developed in the exit. A decelerating inflow deposits bedload in the downstream part of the cavity, while the upstream part is eroded by an accelerating outflow, leading to the retreat of the upstream bank. In the field, strong secondary currents were observed, especially in the inflow, which may enhance the scouring of the downstream corner of the cavity. Also, fine sediment deposits constituted a silt layer in a transitional zone, located between the mouth of the abandoned channel and the oxbow-lake within the cutoff meander. Attempts at morphological prediction should consider not only the flow and sediment conditions in the cavity, but also the dynamics of the main channel. Copyright © 2010 John Wiley & Sons, Ltd [source] Ten-Year Echo/Doppler Determination of the Benefits of Aerobic Exercise after the Age of 65 YearsECHOCARDIOGRAPHY, Issue 1 2010Alexander J. Muster M.D. As the human lifespan becomes progressively extended, potential health-related effects of intense aerobic exercise after age 65 need evaluation. This study evaluates the cardiovascular (CV), pulmonary, and metabolic effects of competitive distance running on age-related deterioration in men between 69 (±3) and 77 (±2) years (mean ± SD). Twelve elderly competitive distance runners (ER) underwent oxygen consumption and echo/Doppler treadmill stress testing (Balke protocol) for up to 10 years. Twelve age-matched sedentary controls (SC) with no history of CV disease were similarly tested and the results compared for the initial three series of the study. CV data clearly separated the ER from SC. At entry, resting and maximal heart rate, systolic/diastolic blood pressure, peak oxygen consumption (VO2max), and E/A ratio of mitral inflow were better in the ER (P < 0.05 vs. SC). With aging, ER had a less deterioration of multiple health parameters. Exceptions were VO2max and left ventricular diastolic function (E/A, AFF, IVRT) that decreased (P < 0.05, Year 10 vs. Year 1). Health advantages of high-level aerobic exercise were demonstrated in the ER when compared to SC. Importantly, data collected in ER over 10 years confirm the benefit of intensive exercise for slowing several negative effects of aging. However, the normative drop of exercise capacity in the seventh and eighth decades reduces the potential athleticism plays in prevention of CV events. (Echocardiography 2010;27:5-10) [source] Age- and Sex-Related Differences in the Tissue Doppler Imaging Parameters of Left Ventricular Diastolic DysfunctionECHOCARDIOGRAPHY, Issue 6 2007Hyeun S. Park M.D. Background: The effect of age and gender on tissue Doppler imaging measurements comparing the septal and mitral annulus needs to be investigated. Methods: We investigated in 276 outpatients in a university cardiology practice the relationship of age and gender to left atrial (LA) size, LA volume, mitral pulse-wave Doppler E/A ratio, E/Ea ratios by tissue Doppler image of mitral annular velocity (TDI), and left ventricular diastolic dysfunction (LVDD) by TDI. Results: Mitral E/A inflow was statistically decreased with age. E/Ea ratios of the lateral and mean of both lateral and septal annulus showed a statistical increase with age, while the E/Ea ratio of the septal annulus did not correlate with age. When comparing men and women of all ages, the mean LA volume for men was 59.2 cm3± 24.36 cm3 versus 48.54 cm3± 16.14 cm3 (P-value < 0.0001) and the mean LA size was 4.0 + 0.51 cm for men and 3.65 + 0.47 for women (P-value < 0.0001). There was no statistical difference between men and women when looking at mitral E/A inflow ratio, deceleration time, E/Ea ratio of the septal annulus, E/Ea ratio of the lateral annulus, E/Ea ratio of the mean of both septal and lateral annulus, and grades of LVDD. Conclusion: In patients 70 years of age or older, the mean diastolic grade was mild-to-moderate LVDD when using lateral or mean of septal and lateral annular measurements. When only the septal annular measurements were used to determine diastolic grade, all four age groups showed a mean of mildly to moderately impaired LVDD and showed no correlation with age. There were no differences in tissue Doppler imaging measurements between men and women. [source] Left Ventricular Function in Male Patients with Secondary HypogonadismECHOCARDIOGRAPHY, Issue 3 2007Oben Baysan M.D. Background: In addition to the effects on ventricular repolarization, testosterone could also affect left ventricular performance. The enhancement of left ventricular contractility in testosterone-deficient rats following testosterone replacement implies to the possible testosterone effect. Objectives: The aim of the current study is to reveal the alterations of left ventricular functions, if any, in secondary hypogonadal male patients. Methods: Thirty-four males with secondary hypogonadism comprised the study group. The control group consisted of 30 healthy subjects. Echocardiographic measurements including left ventricular dimensions, ejection fraction, mitral inflow, and left ventricular outflow parameters were obtained from all subjects. Tissue Doppler parameters were also measured from left ventricular lateral wall and interventricular septum. Results: Left ventricular diameters, wall thicknesses, and performance parameters were similar in both groups. Mitral inflow parameters showed a statistically insignificant difference. Pulse-wave tissue Doppler interpretation of hypogonadal and healthy subjects were similar in terms of lateral and septal basal segment Sm, Em, and Am wave velocities. Conclusions: Regarding the findings of previous studies that showed impaired myocardial contractility and lusitropy in testosterone deficient rats and our study results, further studies are needed for better understanding of testosterone's effects on human myocardium. [source] The Myocardial Performance Index in Patients with Aortic StenosisECHOCARDIOGRAPHY, Issue 4 2002Jude A. Mugerwa M.D. Objectives: This study was designed to determine the effect of chronic afterload on a Doppler-derived myocardial performance index (MPI) combining both systolic and diastolic left ventricular dysfunction. Methods: The study included 36 patients with a diagnosis of aortic stenosis and 36 normal subjects. Doppler-derived myocardial performance index (MPI), defined as the sum of the isovolumic contraction time and isovolumic relaxation time divided by ejection time, was measured from the mitral valve inflow and left ventricular outflow velocity patterns and was then related to the aortic valve area, valve gradient, and other echocardiographic variables. Results: The values of the Doppler-derived MPI in the patients with aortic stenosis were significantly higher than those in the controls (0.54 ± 0.20 vs 0.38 ± 0.04, respectively; P < 0.001). Transmitral deceleration time and the E/A ratio (r = 0.47 and r = 0.35, respectively; P < 0.05) were significant univariate correlates, and mitral deceleration time was the only significant correlate of MPI. However the index did not correlate with aortic valve area, peak and mean valve gradients, left ventricular mass, or age. Conclusions: Doppler-derived MPI reflects severity of global left ventricular dysfunction in patients with aortic stenosis and may be of clinical value in this patient population. [source] Austria's Demand for International Reserves and Monetary Disequilibrium: The Case of a Small Open Economy with a Fixed Exchange Rate RegimeECONOMICA, Issue 281 2004Harald Badinger Using a vector error correction approach, I estimate Austria's demand for international reserves over the period 1985:1,1997:4 and test for short-run effects of the disequilibrium on the national monetary market. I find that Austria's long-run reserve demand can be described as a stable function of imports, uncertainty and the opportunity cost of holding reserves with strong economies of scale. The speed of adjustment takes a value of 38 per cent. The results confirm that an excess of money demand (supply) induces an inflow (outflow) of international reserves as postulated by the monetary approach to the balance of payments. [source] Optimal observability of sustained stochastic competitive inhibition oscillations at organellar volumesFEBS JOURNAL, Issue 1 2006Kevin L. Davis When molecules are present in small numbers, such as is frequently the case in cells, the usual assumptions leading to differential rate equations are invalid and it is necessary to use a stochastic description which takes into account the randomness of reactive encounters in solution. We display a very simple biochemical model, ordinary competitive inhibition with substrate inflow, which is only capable of damped oscillations in the deterministic mass-action rate equation limit, but which displays sustained oscillations in stochastic simulations. We define an observability parameter, which is essentially just the ratio of the amplitude of the oscillations to the mean value of the concentration. A maximum in the observability is seen as the volume is varied, a phenomenon we name system-size observability resonance by analogy with other types of stochastic resonance. For the parameters of this study, the maximum in the observability occurs at volumes similar to those of bacterial cells or of eukaryotic organelles. [source] Restoration options for potential persistence of submersed aquatic vegetation: combining ecological, hydrodynamic and sediment transport modellingFRESHWATER BIOLOGY, Issue 4 2008ELLY P. H. BEST Summary 1. Restoration of shallow turbid lakes to promote growth of submersed aquatic vegetation (SAV) requires knowledge of the environmental factors affecting SAV growth and persistence, and a means to predict the success of SAV reestablishment under different management scenarios to improve these environmental conditions. We used a dynamic ecological modelling approach relating SAV responses to changes in physical and chemical conditions, with information on water level, flow and transparency being provided by hydrodynamic and sediment transport models. 2. The potential persistence of Vallisneria americana was similar under simulated environmental conditions in 1946 and in 1954, as was the potential persistence of Potamogeton pectinatus, indicating that the disappearance of V. americana from Peoria Lake (U.S.A.) previously attributed to an extended spring flood in 1954, may have been related to the combined effects of changes in water level, flow and water transparency as well as possibly other factors. 3. Recent environmental conditions (for 2000) proved not to be conducive for the colonization and persistence potential of V. americana, but would allow colonization by P. pectinatus. The construction of a hypothetical levee along the eastern descending line of the navigation channel in Upper Peoria Lake, which was expected to reduce fetch- and navigation-related turbidity, did not improve the situation for V. americana and overall deteriorated the situation for P. pectinatus. Thus, such a hydraulic alteration, generally considered as beneficial for SAV restoration, may not always be successful. 4. The results of the simulations indicated that the environmental conditions for potential persistence in Peoria Lake were generally less favourable for V. americana than for P. pectinatus. Measures suggested to restore SAV communities in such a lake should aim at reducing concentrations of total suspended solids at the point of inflow by a factor of three to four and limiting fetch- and navigation-related resuspension. [source] Ecological effects of perturbation by drought in flowing watersFRESHWATER BIOLOGY, Issue 7 2003P. S. Lake SUMMARY 1Knowledge of the ecology of droughts in flowing waters is scattered and fragmentary, with much of the available information being gathered opportunistically. Studies on intermittent and arid-zone streams have provided most of the information. 2Drought in streams may be viewed as a disturbance in which water inflow, river flow and water availability fall to extremely low levels for extended periods of time. As an ecological perturbation, there is the disturbance of drought and the responses of the biota to the drought. 3Droughts can either be periodic, seasonal or supra-seasonal events. The types of disturbance for seasonal droughts are presses and for supra-seasonal droughts, ramps. 4In droughts, hydrological connectivity is disrupted. Such disruption range from flow reduction to complete loss of surface water and connectivity. The longitudinal patterns along streams as to where flow ceases and drying up occurs differs between streams. Three patterns are outlined: ,downstream drying', ,headwater drying' and ,mid-reach drying'. 5There are both direct and indirect effects of drought on stream ecosystems. Marked direct effects include loss of water, loss of habitat for aquatic organisms and loss of stream connectivity. Indirect effects include the deterioration of water quality, alteration of food resources, and changes in the strength and structure of interspecific interactions. 6Droughts have marked effects on the densities and size- or age-structure of populations, on community composition and diversity, and on ecosystem processes. 7Organisms can resist the effects of drought by the use of refugia. Survival in refugia may strongly influence the capacity of the biota to recover from droughts once they break. 8Recovery by biota varies markedly between seasonal and supra-seasonal droughts. Faunal recovery from seasonal droughts follows predictable sequences, whilst recovery from supra-seasonal droughts varies from one case to another and may be marked by dense populations of transient species and the depletion of biota that normally occur in the streams. 9The restoration of streams must include the provision of drought refugia and the inclusion of drought in the long-term flow regime. [source] Retinoid signaling and cardiac anteroposterior segmentationGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2001José Xavier-Neto Abstract Summary: Establishment of anterior,posterior polarity is one of the earliest decisions in cardiogenesis. Specification of anterior (outflow) and posterior (inflow) structures ensures proper connections between venous system and inflow tract and between arterial tree and outflow tract. The last few years have witnessed remarkable progress in our understanding of cardiac anteroposterior patterning. Molecular cloning and subsequent studies on RALDH2, the key embryonic retinaldehyde dehydrogenase in retinoic acid (RA) synthesis, provided the missing link between teratogenic studies on RA deficiency and excess and normal chamber morphogenesis. We discuss work establishing the foundations of our current understanding of the mechanisms of cardiac anteroposterior segmentation, the reasons why early evidence pointing to the role of RA in anteroposterior segmentation was overlooked, and the key experiments unraveling the role of RA in cardiac anteroposterior segmentation. We have also integrated recent experiments in a model of cardiac anteroposterior patterning in which RALDH2 expression determines anteroposterior boundaries in the heart field. genesis 31:97,104, 2001. © 2001 Wiley-Liss, Inc. [source] Origin and geochemistry of Miocene marine evaporites associated with red beds: Great Kavir Basin, Central IranGEOLOGICAL JOURNAL, Issue 1 2007Hossain Rahimpour-Bonab Abstract During the Cenozoic numerous shallow epicontinental evaporite basins formed due to tectonic movements in the Northern Province of the Central Iran Tectonic Zone (the Great Kavir Basin). During the Miocene, due to sea-level fluctuations, thick sequences of evaporites and carbonates accumulated in these basins that subsequently were overlain by continental red beds. Development of halite evaporites with substantial thickness in this area implies inflow of seawater along the narrow continental rift axis. The early ocean basin development was initiated in Early Eocene time and continued up to the Middle Miocene in the isolated failed rift arms. Competition between marine and non-marine environments, at the edge of the encroaching sea, produced several sequences of both abrupt and gradual transition from continental wadi sediments to marginal marine evaporites in the studied area. These evaporites show well-preserved textures indicative of relatively shallow-brine pools. The high Br content of these evaporites indicates marine-derived parent brines that were under the sporadic influence of freshening by meteoric water or replenishing seawater. However, the association of hopper and cornet textures denotes stratified brine that filled a relatively large pool and prevented rapid variations in the Br profile. Unstable basin conditions that triggered modification of parent brine chemistry prevailed in this basin and caused variable distribution patterns for different elements in the chloride units. The presence of sylvite and the absence of Mg-sulphate/chlorides in the paragenetic sequence indicate SO4,depleted parent brine in the studied sequence. Petrographic examinations along with geochemical analyses on these potash-bearing halites reveal parental brines which were a mixture of seawater and CaCl2 -rich brines. The source of CaCl2 -rich brines is ascribed to the presence of local rift systems in the Great Kavir Basin up to the end of the Early Miocene. Copyright © 2007 John Wiley & Sons, Ltd. [source] Tapovan-Vishnugad hydroelectric power project , experience with TBM excavation under high rock cover / . Tapovan-Vishnugad Wasserkraftwerk , Erfahrungen mit TBM-Vortrieb bei hoher ÜberlagerungGEOMECHANICS AND TUNNELLING, Issue 5 2010Johann Brandl Mechanised tunnelling - Maschineller Vortrieb; Hydro power plants - Wasserkraftanlagen Abstract NTPC Ltd. of India is presently constructing the 520 MW (4 x 30 MW) Tapovan-Vishnugad hydroelectric power plant in Uttarakhand in the Himalayas. As part of this project, an approximately 12.1 km head race tunnel (HRT) is to be constructed, of which approximately 8.6 km are being excavated by DS-TBM with an excavation diameter of 6.575 m. Construction of this HRT has been awarded to a Joint Venture (JV) of Larsen, Toubro Ltd., India, and Alpine, Austria. Geoconsult ZT GmbH is acting as a Consultant to NTPC Ltd. for the TBM part of the HRT. The overburden above the tunnel is up to 1, 100 m with the result that knowledge of the geology along the HRT alignment could only be based on projections made from surface exposures available in the area. Basically, the ground consists of jointed quartzite, gneiss and schist. Excavation of the HRT started in October 2008 and excavation rates of over 500 m per month were achieved in November 2009. However, in December 2009 the TBM encountered a fault zone along with high-pressure water inflow and became trapped. This paper outlines the present status of HRT construction and describes in particular the difficulties encountered during TBM excavation in fault zones with large high-pressure water inflows and how these problems are being dealt with. Die indische Firma NTPC Ltd. errichtet derzeit das 520 MW (4 x 130 MW) Tapovan-Vishnugad Wasserkraftwerk in Uttarakhand, Himalaya. Als Teil dieses Projekts wird ein ungefähr 12,1 km langer Triebwasserstollen (TWS) errichtet, wobei rund 8,6 km davon mittels einer DS-TBM mit einem Ausbruchdurchmesser von 6.575 m aufgefahren werden. Der Bau dieses Triebwasserstollens wurde an die Arbeitsgemeinschaft Larsen, Toubro Ltd., Indien, und Alpine, Österreich vergeben. Geoconsult ZT GmbH fungiert als Berater von NTPC Ltd. für den TBM-Teil des TWS. Aufgrund der Überlagerung des Tunnels von bis zu 1,100 m konnte die Geologie entlang des Triebwasserstollens nur durch Projektion von vorhandenen Oberflächenaufschlüssen aus der Umgebung bestimmt werden. Das Gebirge besteht hauptsächlich aus geklüftetem Quarzit, Gneis und Schiefer. Der Ausbruch des TWS begann im Oktober 2008. Im November 2009 wurde eine Vortriebsgeschwindigkeit von über 500 m pro Monat erreicht. Im Dezember 2009 jedoch fuhr die TBM eine Störzone mit einem Hochdruckwassereinbruch an, wodurch die TBM stecken blieb. Dieser Artikel skizziert den derzeitigen Stand des TWS und legt besonderes Augenmerk auf die Schwierigkeiten beim Auffahren der Störzone inklusive Hochdruckwassereinbruch mit einer TBM. Darüber hinaus wird gezeigt, wie sich die auftretenden Probleme lösen lassen. [source] Inverse Modeling Approach to Allogenic Karst System CharacterizationGROUND WATER, Issue 3 2009N. Dörfliger Allogenic karst systems function in a particular way that is influenced by the type of water infiltrating through river water losses, by karstification processes, and by water quality. Management of this system requires a good knowledge of its structure and functioning, for which a new methodology based on an inverse modeling approach appears to be well suited. This approach requires both spring and river inflow discharge measurements and a continuous record of chemical parameters in the river and at the spring. The inverse model calculates unit hydrographs and the impulse responses of fluxes from rainfall hydraulic head at the spring or rainfall flux data, the purpose of which is hydrograph separation. Hydrograph reconstruction is done using rainfall and river inflow data as model input and enables definition at each time step of the ratio of each component. Using chemical data, representing event and pre-event water, as input, it is possible to determine the origin of spring water (either fast flow through the epikarstic zone or slow flow through the saturated zone). This study made it possible to improve a conceptual model of allogenic karst system functioning. The methodology is used to study the Bas-Agly and the Cent Font karst systems, two allogenic karst systems in Southern France. [source] Geochemical Tracers to Evaluate Hydrogeologic Controls on River SalinizationGROUND WATER, Issue 3 2008Stephanie J. Moore The salinization of rivers, as indicated by salinity increases in the downstream direction, is characteristic of arid and semiarid regions throughout the world. Historically, salinity increases have been attributed to various mechanisms, including (1) evaporation and concentration during reservoir storage, irrigation, and subsequent reuse; (2) displacement of shallow saline ground water during irrigation; (3) erosion and dissolution of natural deposits; and/or (4) inflow of deep saline and/or geothermal ground water (ground water with elevated water temperature). In this study, investigation of salinity issues focused on identification of relative salinity contributions from anthropogenic and natural sources in the Lower Rio Grande in the New Mexico-Texas border region. Based on the conceptual model of the system, the various sources of water and, therefore, salinity to the Lower Rio Grande were identified, and a sampling plan was designed to characterize these sources. Analysis results for boron (,11B), sulfur (,34S), oxygen (,18O), hydrogen (,2H), and strontium (87Sr/86Sr) isotopes, as well as basic chemical data, confirmed the hypothesis that the dominant salinity contributions are from deep ground water inflow to the Rio Grande. The stable isotopic ratios identified the deep ground water inflow as distinctive, with characteristic isotopic signatures. These analyses indicate that it is not possible to reproduce the observed salinization by evapotranspiration and agricultural processes alone. This investigation further confirms that proper application of multiple isotopic and geochemical tracers can be used to identify and constrain multiple sources of solutes in complex river systems. [source] Calculation of Elapsed Decimal Time for Tracing StudiesGROUND WATER, Issue 1 2008Malcolm S. Field Calculation of time of travel from tracing studies in hydrologic systems is critical to establishing pollutant arrival times from points of inflow to points outflow, calculating subsurface flow velocities, and determining other important transport parameters such as longitudinal dispersion. In addition, breakthrough curve modeling demands accurate time of travel calculations if model results are to have any realistic meaning. However, accurate time of travel calculations are very difficult for long tracer tests in which sampling schedules are not consistent, or when there are major disruptions such as may occur when adverse weather conditions cause automatic sampling equipment to fail. Long and inconsistent sampling times may be accurately converted to decimal times of travel by converting the conventionally recorded Coordinated Universal Time for sampling date and time event to a baseline time standard. By converting to a baseline time standard, all recorded dates and times are linked to the established baseline standard so that each succeeding sampling date and time are correctly determined relative to the previous sampling date and time and to the injection date and time. [source] The Development of New Analytic Elements for Transient Flow and Multiaquifer FlowGROUND WATER, Issue 1 2006O.D.L. Strack We deal in this paper with an ongoing development of the analytic element method. We present in outline new analytic line elements that are suitable to model general flow fields, i.e., flow fields that possess a continuously varying areal inflow or outflow. These elements are constructed specifically to model the leakage through leaky layers that separate aquifers in leaky systems and to model transient effects. The leakage or release from storage underneath linear features is modeled precisely by the new elements; the singularity in leakage is matched exactly by the approximate solution. Applications are given for a problem involving leakage and for a case of transient flow. We note that the analytic elements can be used also to reproduce the effect of continuously varying aquifer properties, e.g., the hydraulic conductivity or the elevation of the base of the aquifer. In the latter case, the elements would reproduce the rotation of the flow field caused by the variation in properties, rather than the divergence as for the case of leakage. [source] Approximate discharge for constant head test with recharging boundaryGROUND WATER, Issue 3 2005Philippe Renard The calculation of the discharge to a constant drawdown well or tunnel in the presence of an infinite linear constant head boundary in an ideal confined aquifer usually relies on the numerical inversion of a Laplace transform solution. Such a solution is used to interpret constant head tests in wells or to roughly estimate ground water inflow into tunnels. In this paper, a simple approximate solution is proposed. Its maximum relative error is on the order of 2% as compared to the exact analytical solution. The approximation is a weighted mean between the early-time and late-time asymptotes. [source] Differential Employment Patterns for Citizens and Non-Citizens in Science and Engineering in the United States: Minting and Competitive EffectsGROWTH AND CHANGE, Issue 4 2004Sharon G. Levin ABSTRACT The consequences of the heavy inflow of foreign talent for U.S. scientists and engineers over the period 1973-1997 are examined using data from the Survey of Doctorate Recipients. Of particular interest is whether non-citizens trained in the United States have displaced citizens from jobs in science and engineering (S&E). Using a novel adaptation of the shift-share technique, it is shown that citizen S&E doctorates have fewer jobs in S&E and fewer academic jobs than their non-citizen counterparts for two reasons: the citizen doctoral population has experienced slower growth than the non-citizen doctoral population, and citizen S&E doctorates have been displaced. Whether the displacement observed was a voluntary response of citizens to the lure of better opportunities elsewhere or an involuntary response indicative of having been pushed out by foreign talent remains to be determined. [source] Dysfunctional very-low-density lipoprotein synthesis and release is a key factor in nonalcoholic steatohepatitis pathogenesis,,HEPATOLOGY, Issue 3 2009Koji Fujita The specific mechanisms of nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH) pathogenesis remain unknown. In the present study we investigated the differences between NAFL and NASH in terms of liver lipid metabolites and serum lipoprotein. In all, 104 Japanese subjects (50 men and 54 postmenopausal women) with histologically verified NAFL disease (NAFLD) (51 with NAFL, 53 with NASH) were evaluated; all diagnoses were based on liver biopsy findings and the proposed diagnostic criteria. To investigate the differences between NAFL and NASH in humans, we carefully examined (1) lipid inflow in the liver, (2) lipid outflow from the liver, (3) very-low-density lipoprotein (VLDL) synthesis in the liver, (4) triglyceride (TG) metabolites in the liver, and (5) lipid changes and oxidative DNA damage. Most of the hepatic lipid metabolite profiles were similar in the NAFL and NASH groups. However, VLDL synthesis and lipid outflow from the liver were impaired, and surplus TGs might have been produced as a result of lipid oxidation and oxidative DNA damage in the NASH group. Conclusion: A growing body of literature suggests that a deterioration in fatty acid oxidation and VLDL secretion from the liver, caused by the impediment of VLDL synthesis, might induce serious lipid oxidation and DNA oxidative damage, impacting the degree of liver injury and thereby contributing to the progression of NASH. Therefore, dysfunctional VLDL synthesis and release may be a key factor in progression to NASH. (HEPATOLOGY 2009.) [source] The effect of riparian land use on transport hydraulics in agricultural headwater streams located in northeast Ohio, USAHYDROLOGICAL PROCESSES, Issue 1 2010Kyle S. Herrman Abstract This study examined if riparian land use (forested vs agricultural) affects hydraulic transport in headwater streams located in an agriculturally fragmented watershed. We identified paired 50-m reaches (one reach in agricultural land use and the other in forested land use) along three headwater streams in the Upper Sugar Creek Watershed in northeast Ohio, USA (40° 51,42,N, 81° 50,29,W). Using breakthrough curves obtained by Rhodamine WT slug injections and the one-dimensional transport with inflow and storage model (OTIS), hydraulic transport parameters were obtained for each reach on six different occasions (n = 36). Relative transient storage (AS:A) was similar between both reach types (As: A = 0·3 ± 0·1 for both agricultural and forested reaches). Comparing values of Fmed200 to those in the literature indicates that the effect of transient storage was moderately high in the study streams in the Upper Sugar Creek Watershed. Examining travel times revealed that overall residence time (HRT) and residence time in transient storage (TSTO) were both longer in forested reaches (forested HRT = 19·1 ± 11·5 min and TSTO = 4·0 ± 3·8 min; agricultural HRT = 9·3 ± 5·3 min and TSTO = 1·7 ± 1·4 min). We concluded that the effect of transient storage on solute transport was similar between the forested and agricultural reaches but the forested reaches had a greater potential to retain solutes as a result of longer travel times. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modelling lake stage and water balance of Lake Tana, EthiopiaHYDROLOGICAL PROCESSES, Issue 25 2009Yirgalem A. Chebud Abstract The level of Lake Tana, Ethiopia, fluctuates annually and seasonally following the patterns of changes in precipitation. In this study, a mass balance approach is used to estimate the hydrological balance of the lake. Water influx from four major rivers, subsurface inflow from the floodplains, precipitation, outflow from the lake constituting river discharge and evapotranspiration from the lake are analysed on monthly and annual bases. Spatial interpolation of precipitation using rain gauge data was conducted using kriging. Outflow from the lake was identified as the evaporation from the lake's surface as well as discharge at the outlet where the Blue Nile commences. Groundwater inflow is estimated using MODular three-dimensional finite-difference ground-water FLOW model software that showed an aligned flow pattern to the river channels. The groundwater outflow is considered negligible based on the secondary sources that confirmed the absence of lake water geochemical mixing outside of the basin. Evaporation is estimated using Penman's, Meyer's and Thornwaite's methods to compare the mass balance and energy balance approaches. Meteorological data, satellite images and temperature perturbation simulations from Global Historical Climate Network of National Oceanographic and Atmospheric Administration are employed for estimation of evaporation input parameters. The difference of the inflow and outflow was taken as storage in depth and compared with the measured water level fluctuations. The study has shown that the monthly and annually calculated lake level replicates the observed values with root mean square error value of 0·17 and 0·15 m, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] Interactions between a saline lagoon and a semi-confined aquifer on a salinized floodplain of the lower River Murray, southeastern AustraliaHYDROLOGICAL PROCESSES, Issue 24 2009E. W. Banks Abstract The transport of saline groundwater from local and regional aquifers to the lower River Murray in South Australia is thought to be greatly influenced by the incised lagoons and wetlands that are present in the adjacent floodplain. Interactions between a saline lagoon and semi-confined aquifer at a floodplain on the River Murray were studied over a 1-year period using hydrogeological techniques and environmental tracers (Cl,, ,2H and ,18O). Piezometric surface monitoring showed that the lagoon acted as a flow-through system intercepting local and regional groundwater flow. A chloride mass balance determined that approximately 70% of the lagoon winter volume was lost by evaporation. A stable isotope mass balance estimated leakage from the lagoon to the underlying aquifer. Around 0,38% of the total groundwater inflow into the lagoon was lost to leakage compared to 62,100% of groundwater inflow lost to evaporation. Overall, floodplain wetlands of the type studied here behave as groundwater flow-through systems. They intercept groundwater discharge, concentrate it and eventually recharge more saline water to the floodplain aquifer. Understanding groundwater,surface water interactions in floodplain wetlands will benefit the effective management of salinity in semi-arid rivers. Copyright © 2009 John Wiley & Sons, Ltd. [source] Transient storage and downstream solute transport in nested stream reaches affected by beaver damsHYDROLOGICAL PROCESSES, Issue 17 2009Li Jin Abstract Transient storage constitutes a key element in the hydrologic cycle of watersheds. Both in-channel slow moving water (dead zones) and hyporheic zones can contribute to transient storage, which retains water and solutes, increases residence time and influences solute transport in streams. Beaver dams and other in-stream obstructions throughout low-order streams attenuate streamflow and provide dead zone storage in pools. In this article, we report the results of four tracer tests in nested stream reaches in Cherry Creek (Wyoming, USA) covering ,2·5 km of stream length to explore how the degree of beaver dam obstructions and their impoundments influence water transient storage and downstream solute transport in low-order streams in the Rocky Mountain region of the American West. Travel-time parameters for the tracer tests increased linearly with beaver dam number (N) and pond size (V). Linear regression of the travel time to the peak concentration (Tp), the leading (Tl) and tailing edge (Tt) of the dye cloud and the duration of the dye cloud (Td) versus N and V were all significant (R2 = 0·99). Slopes of the linear regressions of Tt versus N and V, were three times larger than those for Tl, suggesting that longer residence times may be caused, in part, by transient storage in the stream system. One-dimensional transport with inflow and storage (OTIS) modelled cross-sectional area of transient storage zone (As) and dispersion coefficients (D) increased linearly with N and V and reach length. Two transient storage metrics, Fmean and , also showed a general increase with N and V, although the relationship was not as strong. This suggests that in-channel dead zones associated with beaver dams provide opportunities for generating transient water storage. The linear relationship between dispersion coefficient and reach length suggests the dispersion process might be analogous to the hydrodynamic dispersion in groundwater settings. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||