New analytical solution for the study of hydraulic interaction between Alpine tunnels and groundwater

2003 ◽  
Vol 174 (5) ◽  
pp. 441-448 ◽  
Author(s):  
Jean-Christophe Maréchal ◽  
Pierre Perrochet
Keyword(s):  
Analytical Solution ◽  
Surface Waters ◽  
Discharge Rate ◽  
Water Discharge ◽  
Rate Condition ◽  
Type Curves ◽  
Discharge Rates ◽  
The Alps ◽  
Surface Monitoring ◽  
Tunnel Discharge

Abstract The present paper addresses two major problems encountered during tunnel drilling and related to the hydraulic interaction with surrounding groundwater bodies. The first one is the prediction of water discharge into the tunnel, as a function of the geometric and hydrogeological data. The second problem is related to the assessment of the draining effects on surface waters (springs, lakes, wetlands). Surface monitoring campaigns are costly and evaluating their duration is a sensitive question. Both problems are tightly related and depend on aquifer dynamics. It is shown that in a geological context with steeply dipping structures, nearly vertical, inducing series of aquifers and aquicludes such as in the Alps, the drainage of the aquifer by the tunnel can be modelled by the analytical solution of Jacob and Lohman [1952] for artesian wells. First developed for horizontal, confined unsteady flow towards a vertical well with constant drawdown, it is adapted here to a horizontal tunnel by a rotation of π/2. The main difference between this solution and more classical Theis’ solutions is that a constant drawdown condition replaces the constant discharge rate condition. Hence, a relation is obtained for the time-dependent discharge rate Q(t) detected at the tunnel after drilling, as a function of aquifer transmissivity (T), storage coefficient (S), initial drawdown (so) and tunnel radius (ro). This analytical solution is compared to a finite-elements model simulating a draining tunnel in a simplified 2D vertical cross-section. The comparisons show that the decay of the tunnel discharge can be divided into two periods. During the first period, radial drawdown develops around the tunnel and there is excellent match between analytical and numerical results. Tunnel discharge results from the decompression of rock and water (storage effects) as a response to the sudden initial drawdown at the tunnel location. During the second period, the drawdown cone reaches the aquifer limits (lateral and upper) and numerical discharge rates decrease faster than analytical rates because of hydraulic heads decline at the aquifer limits. In the Alps, such trends were observed for the discharge rates into the Simplon and Mont-Blanc tunnels, and the analytical solution of Jacob and Lohman [1952] was applied to the first discharge period to evaluate aquifer transmissivity and storage coefficients. As indicated by the simulations, and corroborated by field observations, the analytical solution is only valid during a first period after tunnel opening, the duration of which scaling with the inverse of the aquifer diffusivity (T/S). In the second part of the paper, dimensionless type-curves are presented to enable rapid evaluation of the time where a given drawdown is observed at a given distance from the tunnel. Accounting for tunnel geometry (radius and depth) and aquifer parametres (T and S), these curves could for instance help in practice to determine when surface waters would start to be affected by a draining tunnel underneath. Although neglecting the boundary effects discussed in the first part of the paper, these type-curves demonstrate the great inertia of mountain aquifers, and could be used to adjust the duration of surface monitoring campaigns according to the specific tunnel/aquifer settings.

scholarly journals KELANGSUNGAN HIDUP BENIH IKAN BETOK (Anabas testudineus, BL) DENGAN DEBIT AIR YANG BERBEDA PADA SISTEM RESIRKULASI

2018 ◽  
Vol 3 (1) ◽  
pp. 12
Author(s):  
Azrianto Azrianto ◽  
Muhammad Sugihartono ◽  
Muarofah Ghofur
Keyword(s):  
Survival Rate ◽  
Discharge Rate ◽  
Water Discharge ◽  
Water Volume ◽  
Anabas Testudineus ◽  
Important Type ◽  
Discharge Rates ◽  
Survival And Growth ◽  
Optimum Water

Fish betok (Anabas testudineus, BL) is a type of fish that live and breed naturally, especially in the swamps of Lebak on the island of Sumatra and Kalimantan. The fish is an important type of fish in public waters. In general, the price of fish cake in Indonesia ranges from Rp 20.000,00 to Rp 40.000,00 per kg for that there needs to be efforts to increase production. The purpose of this research is to know the optimum water discharge rate for survival and growth of fish seeds of betok. This study used four differents water discharge rates, without water discharge, 10 ml / sec, 20 ml / sec and 30 ml / sec. The fish seeds are then stocked into an aquarium with a water volume of 49 liters with a density of 2-tail fish / liter. The results showed that the water discharge rate of 30 ml / sec gave the best survival rate and growth of the best fish seeds.  AbstrakIkan betok (Anabas testudineus, BL) merupakan jenis ikan yang hidup dan berkembang biak secara alami terutama di rawa lebak di Pulau Sumatera dan Kalimantan. Ikan betok merupakan jenis ikan ekonomis penting di perairan umum. Secara umum harga ikan betok di Indonesia berkisar antara Rp 20.000,00 sampai Rp 40.000,00 per kg untuk itu perlu ada upaya penimgkatan produksi. Tujuan penelitian ini untuk mengetahui debit air yang optimal untuk kelangsungan hidup dan pertumbuhan benih ikan betok. Penelitian ini menggunakan 4 perlakuan laju debit air yang berbeda yaitu tanpa debit air, 10 ml/detik, 20 ml/detik dan 30 ml/detik. Benih ikan betok kemudian ditebar ke dalam akuarium dengan volume air sebanyak 49 liter dengan kepadatan benih ikan betok 2 ekor/liter. Hasil penelitian menunjukkan bahwa laju debit air sebanyak 30 ml/detik memberikan tingkat kelangsungan hidup benih ikan betok terbaik.  Kata Kunci : Benih betok, sistem resirkulasi, debit air, kelangsungan hidup, kualitas air

scholarly journals Methods of the Real-time Runoff Account under the Conditions of the Bed Silting (the Matyra River in the village of Krutoye range as a study case)

2017 ◽  
Author(s):  
Keyword(s):  
Real Time ◽  
Discharge Rate ◽  
Water Discharge ◽  
Water Levels ◽  
Accounting Data ◽  
The Real ◽  
Discharge Rates ◽  
Auto Correlation Function ◽  
The Village ◽  
Adequate Reliability

This paper presents the updated method of the real-time runoff calculation in conditions of river channel silting based on the method of optimal extrapolation. The Matyra river used as the example. The results of the analysis of the data obtained by observations of the Matyra River water regime during the period from 1994 to 2013 have been presented. We have analyzed all specific features of the hydrologic regime characteristics alterations under the influence of meteorological factors over the periods of the bed silting. The proposed decisions for real-time runoff account employ basic many-year dependence of the water discharge rates on water levels that have been exactly defined by the latest measurements of the water discharge rate through introduction of corrections that characterize changing of the bed passage ability of the year under consideration. These changes are calculated by the method of optimal extrapolation of the series of relative deviations from many-year water discharge curve calculated over the year under consideration. Assessment of the statistic characteristics of the relative deviation series such as auto-correlation function, dispersion and expectation value has been done to calculate weight coefficients in the optimal extrapolation formulas. Assessment of the proposals effectiveness has been carried out on the basis of the data of realtime and regime runoff accounting over the 2008-2013 period. Root mean square deviations from the regime accounting data were 5–10 %. The obtained results enable to make a conclusion on adequate reliability of the real-time runoff accounting data obtained with the use of the developed methods and to recommend it for real-time accounting of the small and medium-sized considerably silted rivers runoff.

scholarly journals Laboratory modelling of the effects of temporal changes of estuarine-fresh-water discharge rates on the propagation speed of oceanographic coastal currents

2010 ◽  
Vol 664 ◽  
pp. 337-347
Author(s):  
PETER J. THOMAS ◽  
P. F. LINDEN
Keyword(s):  
Discharge Rate ◽  
Water Discharge ◽  
Propagation Speed ◽  
Current Speed ◽  
Discharge Condition ◽  
Kelvin Wave ◽  
Coastal Currents ◽  
Discharge Rates ◽  
The Mean ◽  
Fresh Water Discharge

In this paper, results of laboratory experiments simulating buoyancy-driven coastal currents produced by estuarine discharges into the ocean, are discussed. The responses of the propagation speeds of the currents to increases and decreases of the volumetric discharge rate at the source are investigated. For increasing discharge rate, we find that the mean speed of the current head displays a sharp rise some time after the source discharge condition has changed. In contrast, a decrease of the current speed following a decreasing discharge rate proceeds gradually. The current speed after acceleration or deceleration is found to be equal to the speed that would be expected had the discharge been at the higher or lower rate from the start of the experiment. The relative speed at which the information of the changed discharge condition at the source approaches the advancing current head from upstream, for both increasing and decreasing discharge rates, is found to be approximately one to three times the mean speed of the current. Further, we find that this transmission speed is 0.82±0.20 times the propagation speed of a linear, long interfacial Kelvin wave.

The ENT emergency clinic: does senior input matter?

2012 ◽  
Vol 127 (1) ◽  
pp. 15-19 ◽  
Author(s):  
A Mirza ◽  
L McClelland ◽  
M Daniel ◽  
N Jones
Keyword(s):  
Quality Of Care ◽  
Discharge Rate ◽  
Surrogate Marker ◽  
Operating Theatre ◽  
Number Of Children ◽  
Discharge Rates ◽  
Time Period ◽  
Number Of Patients

AbstractBackground:Many ENT conditions can be treated in the emergency clinic on an ambulatory basis. Our clinic traditionally had been run by foundation year two and specialty trainee doctors (period one). However, with perceived increasing inexperience, a dedicated registrar was assigned to support the clinic (period two). This study compared admission and discharge rates for periods one and two to assess if greater registrar input affected discharge rate; an increase in discharge rate was used as a surrogate marker of efficiency.Method:Data was collected prospectively for patients seen in the ENT emergency clinic between 1 August 2009 and 31 July 2011. Time period one included data from patients seen between 1 August 2009 and 31 July 2010, and time period two included data collected between 1 August 2010 and 31 July 2011.Results:The introduction of greater registrar support increased the number of patients that were discharged, and led to a reduction in the number of children requiring the operating theatre.Conclusion:The findings, which were determined using clinic outcomes as markers of the quality of care, highlighted the benefits of increasing senior input within the ENT emergency clinic.

Pain-induced changes in motor unit discharge depend on recruitment threshold and contraction speed

2021 ◽  
Author(s):  
Eduardo Martinez-Valdes ◽  
Francesco Negro ◽  
Michail Arvanitidis ◽  
Dario Farina ◽  
Deborah Falla
Keyword(s):  
Discharge Rate ◽  
Tibialis Anterior Muscle ◽  
Maximum Voluntary Contraction ◽  
Motor Units ◽  
Inhibitory Effect ◽  
Voluntary Contraction ◽  
Recruitment Threshold ◽  
Contraction Speed ◽  
Discharge Rates ◽  
Hypertonic Saline Injection

At high forces, the discharge rates of lower and higher threshold motor units (MU) are influenced in a different way by muscle pain. These differential effects may be particularly important for performing contractions at different speeds since the proportion of lower and higher threshold MUs recruited varies with contraction velocity. We investigated whether MU discharge and recruitment strategies are differentially affected by pain depending on their recruitment threshold (RT), across a range of contraction speeds. Participants performed ankle dorsiflexion sinusoidal-isometric contractions at two frequencies (0.25Hz and 1Hz) and two modulation amplitudes [5% and 10% of the maximum voluntary contraction (MVC)] with a mean target torque of 20%MVC. High-density surface electromyography recordings from the tibialis anterior muscle were decomposed and the same MUs were tracked across painful (hypertonic saline injection) and non-painful conditions. Torque variability, mean discharge rate (MDR), DR variability (DRvar), RT and the delay between the cumulative spike train and the resultant torque output (neuromechanical delay, NMD) were assessed. The average RT was greater at faster contraction velocities (p=0.01) but was not affected by pain. At the fastest contraction speed, torque variability and DRvar were reduced (p<0.05) and MDR was maintained. Conversely, MDR decreased and DRvar and NMD increased significantly during pain at slow contraction speeds (p<0.05). These results show that reductions in contraction amplitude and increased recruitment of higher threshold MUs at fast contraction speeds appears to compensate for the inhibitory effect of nociceptive inputs on lower threshold MUs, allowing the exertion of fast submaximal contractions during pain.

Binaural processing of sound pressure level in the inferior colliculus

1987 ◽  
Vol 57 (4) ◽  
pp. 1130-1147 ◽  
Author(s):  
M. N. Semple ◽  
L. M. Kitzes
Keyword(s):  
Inferior Colliculus ◽  
Sound Pressure ◽  
Spatial Information ◽  
Discharge Rate ◽  
Excitatory Input ◽  
Central Nucleus ◽  
Intensity Difference ◽  
Inhibitory Input ◽  
Directional Information ◽  
Discharge Rates

The central auditory system could encode information about the location of a high-frequency sound source by comparing the sound pressure levels at the ears. Two potential computations are the interaural intensity difference (IID) and the average binaural intensity (ABI). In this study of the central nucleus of the inferior colliculus (ICC) of the anesthetized gerbil, we demonstrate that responses of 85% of the 97 single units in our sample were jointly influenced by IID and ABI. For a given ABI, discharge rate of most units is a sigmoidal function of IID, and peak rates occur at IIDs favoring the contralateral ear. Most commonly, successive increments of ABI cause successive shifts of the IID functions toward IIDs favoring the ipsilateral ear. Neurons displaying this behavior include many that would conventionally be classified EI (receiving predominantly excitatory input arising from one ear and inhibitory input from the other), many that would be classified EE (receiving predominantly excitatory input arising from each ear), and all that are responsive only to contralateral stimulation. The IID sensitivity of a very few EI neurons is unaffected by ABI, except near threshold. Such units could provide directional information that is independent of source intensity. A few EE neurons are very sensitive to ABI, but are minimally sensitive to IID. Nevertheless, our data indicate that responses of most EE units in ICC are strongly dominated by excitation of contralateral origin. For some units, discharge rate is nonmonotonically related to IID and is maximal when the stimuli at the two ears are of comparable sound pressure. This preference for zero IID is common for all binaural levels. Many EI neurons respond nonmonotonically to ABI. Discharge rates are greater for IIDs representative of contralateral space and are maximal at a single best ABI. For a subset of these neurons, the influence arising from the ipsilateral ear is comprised of a mixture of excitation and inhibition. As a consequence, discharge rates are nonmonotonically related not only to ABI but also to IID. This dual nonmonotonicity creates a clear focus of peak response at a particular ABI/IID combination. Because of their mixed monaural influences, such units would be ascribed to different classes of the conventional (EE/EI) binaural classification scheme depending on the binaural level presented. Several response classes were identified in this study, and each might contribute differently to the encoding of spatial information.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals A Case Study On Predicting The Environmental Impacts Of Untreated Effluent Generated From Tannery Industrial Estate In Dhaka, Bangladesh

2020 ◽  
Vol 13 (3) ◽  
pp. 22-31
Author(s):  
Shakil A. Masum ◽  
Md. Sultanul Islam
Keyword(s):  
Environmental Impact ◽  
Discharge Rate ◽  
Soil Aggregates ◽  
Elevated Concentration ◽  
Natural Ecosystem ◽  
Industrial Site ◽  
Discharge Rates ◽  
Regulatory Standard ◽  
Order Of Magnitude ◽  
Recommended Guidelines

Significant amounts of heavy metals in the directly discharged wastewater released from the newly built tannery industrial site in Dhaka, Bangladesh are reported. Despite their detrimental impacts on public health and natural ecosystem, no environmental impact study is yet conducted. Therefore, information on safe discharge rates are not available. In this study, the extent of pollution around the industrial site is investigated for four representative trace metals. Temporal and spatial distributions of chromium (Cr), lead (Pb), cadmium (Cd) and arsenic (As) have been predicted using a numerical model with the aim to estimate safe discharge of these metal contaminants. From multiple simulation runs it has been estimated that a discharge of0.026 m3 of wastewater per day can lead to high levels of Cr and Pb accumulation, exceeding the regulatory standard limits, in the study area. Whilst As and Cd concentrations remain below the advised limits in most cases at this rate. However, an order of magnitude reduction in the total discharge rate, i.e.,0.0026 m3 per day, results into the metal accumulation below the recommended guidelines in all cases. Elevated concentration of Pb is found to be limited to the top 0.5 m of the soil as compared to Cr, As and Cd, which exhibit larger spread along the depth of the soil. The relative dominance of the metal contamination follows the sequence: Pb>Cr>As>Cd as sorbed concentration in soil aggregates and Cr>Pb>As>Cd as aqueous concentration in soil porewater. Further investigations that are essential for a comprehensive environmental impact assessment have been highlighted.

scholarly journals EAST RIVER BATTLE FOR SHEEN: SKIMMING AN OIL SHEEN IN A 3- TO 5-KNOT CURRENT

2001 ◽  
Vol 2001 (2) ◽  
pp. 1431-1434
Author(s):  
Dennis E. Connelly ◽  
Dennis J. McCarthy ◽  
John E. Westerlind
Keyword(s):  
New York ◽  
Current Flow ◽  
Discharge Rate ◽  
Water Discharge ◽  
Cooling Water ◽  
High Discharge ◽  
East River ◽  
Discharge Canal ◽  
High Discharge Rate ◽  
Set Up

ABSTRACT This paper explores the challenges involved with the recovery of oil from a discharge canal with limited access and high relative currents. In March 1999, a sheen was observed in the cooling water discharge canal of Consolidated Edison's 2.5-million kilowatt generating station in Queens (New York City), New York At the time the sheen was discovered, the entire station had been shut down for several months for a maintenance outage. As the tide rose and fell in the East River, into which the discharge canal emptied, the oil sheen moved in and out of a 1,000-foot long tunnel connecting the generating station to the canal. The major challenges to the recovery and removal of the oil sheen were: (1) the low over head of the discharge tunnel and canal support girders, which prevented getting a skimmer into the tunnel and canal; (2) the high discharge rate of the station's cooling water pump; and (3) skimming the sheen in a 3-to 5-knot current. Consolidated Edison is a member of Clean Harbors Cooperative, L.L.C, which was brought in to remove the sheen. This was accomplished utilizing two JBF Scientific DIP Belt Skimmers, which were set up parallel to the current flow, and deflection booming.

scholarly journals QUALITY CHARACTERISTICS OF SURFACE WATERS AT ASPROLAKKAS RIVER BASIN, N.E. CHALKIDIKI, GREECE

2017 ◽  
Vol 43 (4) ◽  
pp. 1737
Author(s):  
E. Kelepertzis ◽  
A. Argyraki ◽  
E. Daftsis ◽  
D. Ballas
Keyword(s):  
Surface Waters ◽  
Water Samples ◽  
Major Ions ◽  
Stream Water ◽  
Water Discharge ◽  
Sampling Period ◽  
Quality Characteristics ◽  
Sampling Point ◽  
The Past ◽  
Surface Water Samples

The present study reports on a four sampling period (April 2008-July 2008-November 2008-February 2009) study of water quality in streams of NE Chalkidiki. A total of 80 surface water samples were collected and analysed for the major ions Ca2+, Mg2+, K+, Na+, Cl- , HCO3 - , SO4 2-, NO3 - and the trace elements Pb, Fe, Cd, Cu, Cr, Ni, Zn, Mn and As. Also pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Temperature, as well as the stream water discharge at each sampling point, were determined in the field. The treatment and the subsequent evaluation of the data showed that the water samples are divided into three separate groups, reflecting the chemistry of water in the three sub-basins of the area i.e., Kokkinolakkas, Kerasia and Piavitsa. The water of the first one is possibly affected by the past mining activities of the area, whereas samples from the other two reflect the influence of sulphide mineralization on the hydrogeochemistry of the corresponding streams. No effect of the seasonal differentiation of stream water discharge was observed.

Suppression of Sheet Cavitation Inception by Water Discharge Through Slit

1987 ◽  
Vol 109 (1) ◽  
pp. 70-74 ◽  
Author(s):  
Hiroharu Kato ◽  
Hajime Yamaguchi ◽  
Shinzo Okada ◽  
Kohei Kikuchi ◽  
Masaru Miyanaga
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Discharge Rate ◽  
Water Discharge ◽  
Cavitation Inception ◽  
Suppression Effect ◽  
Sheet Cavitation ◽  
Effect Of Water

This paper studies experimentally the suppression effect of water discharge on incipient and developed sheet cavitation on a hemispherical headform. The water is discharged tangentially from a slit upstream of a cavitating region into the boundary layer on the headform. Increasing the discharge rate, the length of the sheet cavity becomes shorter and then the cavity is suppressed completely. Flow visualization test shows the generation of wavy motion in the boundary layer which disturbs the separated zone, resulting in disappearance of the sheet cavitation.

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