Lateral Discharge Research Articles

Development of a Water Surface Level Prediction Method Affected by River Mouth Sandbar Collapse

The purpose of this study is to apply a non-linear filtering methods (Particle Filter) to a flood prediction system to improve the accuracy of flood water level. The uniqueness of the flood prediction system is to estimates the water level considering temporal change of the sandbar collapse at the backwater reach in the Kumano River. A one dimensional hydrodynamic model of unsteady flow was applied to predict the longitudinal profile of the water level at the reach affected by the sandbar collapse of the river mouth. It was shown that the bed deformation height as one of the state quantities could explain the timing of the sandbar collapse. Other state quantities are discharge at the upstream and the lateral discharge from the branches. These were given from the results of a distributed rainfall-runoff model. Error coefficients are included to update the state quantities by using filtering method with the observed water level. The water level at the objective river of the study was predicted by using the updated initial condition after the filtering, which showed a good agreement with observed water level. It is concluded that the precision of the flood prediction system combined the water surface level prediction model are improved more than before.

Evaluation of the relationships between rainfall infiltration properties and the lateral flow discharge of a slope based on artificial rain experiments

Evaluation of the relationships between rainfall infiltration properties and the lateral flow discharge of a slope based on artificial rain experiments

Computer-Based Analysis of Hydraulic Design Variables for Uniformly Sloping Microirrigation System Laterals

AbstractAdequate analysis of lateral hydraulics is a very important concern for the design and evaluation of microirrigation systems. One of the main tasks of the lateral hydraulic calculation is to determine the pipe geometric characteristics (pipe size and length) with the required operating inlet pressure head, and the total friction head losses along the lateral line, assuming that the total flow rate at the inlet, characteristics of the emitter, and the acceptable level of uniformity are known in advance. This paper aims to present an efficient computer program in Visual Basic 6.0, named “Multi-flowCAD,” which is based on a stepwise computation algorithm for determining the hydraulic design variables (pipe size, pipe length, and operating inlet pressure head) and the hydraulic flow characteristics (emitter outflow-pressure head distribution, lateral discharge, and total friction losses) along the energy-grade line. The stepwise algorithm takes into account the velocity head change and variation of th...

Snowblower injuries to the hand

The aim of this study was to describe the nature and incidence of hand injuries caused by snowblowers, as well as the accident conditions and accident prevention. We conducted a retrospective evaluation over ten consecutive winters. Nine patients were included. All were men with an average age of 49.7 years (17–71). The accidents occurred at home in seven out of nine patients. The machine was running in 50% of the injury events. In most cases, the injuries occurred when the patient tried to unclog snow from the lateral discharge chute. Only four out of the nine patients had read the instructions or received instructions from the salesperson. The dominant hand was injured in 7 out of 9 patients. An average of 2.7 fingers were injured. The longest fingers were most commonly injured: 8 middle fingers, 7 ring fingers, 4 little fingers, 2 indexes and 1 thumb. All the fractures were open. Three patients were operated on several times. In 7 out of 9 cases, the patients had sequelae such as amputation. The mean time off work was 11.4 weeks (3–24). All the patients were experienced snowblower users (9 years and 57th use on average). Snowblower accidents are very mutilating. Prevention must include protected access to blades and better verbal and written safety warnings.

Characterizing the machining effects of lateral electrodes in electrical discharge machining

Electrical discharge machining (EDM) can easily machine the high strength materials. However, EDM is conventionally the up-anddown machining for the mold and hole; grooves and curved surfaces on the side walls of the blind hole are difficult produced in general EDM. This study developed two electrodes that could create the lateral discharge on the workpiece in EDM. One is an elastic electrode, where two thin copper plates are stuck on the two rectangular pieces of spring steel that could produce a lateral deformation in EDM. This electrode uses the driving force to change the lateral shape of the steel plate to perform the side discharge machining; the other one is the lateral feeding electrode, where two inclined electrodes with angle 45° in the up and down position are jostled to create side deformation, and side grooves or side curved surface could be performed in the discharge process. As a result, the elastic electrode performs poor efficiency in the lateral EDM because of the fast wearing of the thin copper plate. However, lateral feeding electrode enhances the discharge effect of the elastic electrode and results in good efficiency of the plow grooves or curved surface produced in the blind hole.

Groundwater – Geothermal preliminary model of the Acque Albule Basin (Rome): future perspectives of geothermal resources exploitation

This work presents the preliminary results of a groundwater and geothermal model applied to the hydrothermal system of the Tivoli- Guidonia plain, located in the east surroundings of Rome. This area, which is characterized by a thick outcropping travertine deposit, has been an important quarry extraction area since roman age. Today the extraction is in deepening helped by a large dewatering action. By an hydrogeological point of view, the travertine aquifer of the Tivoli- Guidonia Plain, is recharged by lateral discharge in the Lucretili and Cornicolani Mts., and by piping trough important regional faults, located in the basal aquiclude, in the central area of the basin. Piping hydrothermal groundwater is the main contribution on flow in the basin. Preliminary simulations of the groundwater-geothermal model, reproduce quite well the heat and mineralization plumes of groundwater observed in the travertine aquifer.

Drainage from water‐filled crevasses along the margins of Jakobshavn Isbræ: A potential catalyst for catchment expansion

Saturated crevasses occur in local depressions within the shear margins of Jakobshavn Isbræ at inflections in the ice stream's flow direction. Spatio‐temporal variability of seven distinctive saturated crevasse groups was examined during the 2007 melt season. The area of saturated crevasses reached its maximum extent, ~1.8 km2, in early July, and remained largely constant until early August. Filling rates are correlated with regional melt production, while drainage rates are highly correlated with areal extent. Estimates on potential drainage volume from the largest crevasse system are ~9.23 × 10−3 km3 ± 2.15 × 10−8 km3 and ~ 4.92 × 10−2 km3 ± 3.58 × 10−8 km3, respectively, over a 16 day interval and are more than required for a distributed basal hydrologic system across this area to temporarily flood bedrock obstacles believed to control basal sliding. Future drainage events, likely extending farther inland with warming, could result in enhanced lateral mass discharge into the ice stream, with implications for the dynamic evolution of the entire basin.

Analytic solutions to transient groundwater flow under time-dependent sources in a heterogeneous aquifer bounded by fluctuating river stage

Analytical solutions for the water table and lateral discharge in a heterogeneous unconfined aquifer with time-dependent source and fluctuating river stage were derived and compared with those in an equivalent homogeneous aquifer. The heterogeneous aquifer considered consists of a number of sections of different hydraulic conductivity values. The source term and river stage were assumed to be time-dependent but spatially uniform. The solutions derived is useful in studying various groundwater flow problems in a horizontally heterogeneous aquifer since the spatially piecewise-constant hydraulic conductivity and temporally piecewise-constant recharge and lateral discharge can be used to quantify variations in these processes commonly observed in reality. Applying the solutions derived to an aquifer of three sections of different hydraulic conductivity values shown that (1) the aquifer heterogeneity significantly increases the spatial variation of the water table and thus its gradient but it has little effect on lateral discharge in the case of temporally and spatially uniform recharge, (2) the time-dependent but spatially uniform recharge increases the temporal variation of groundwater table over the entire aquifer but its effect on lateral discharge is limited in the zone near the river, and (3) the effect of river stage fluctuation on the water table and lateral discharge is limited in the zone near the river and the effect of the heterogeneity is to increase lateral discharge to or recharge from the river.

Field Evaluation of Arid Soils Wetting Pattern in Subsurface Drip Irrigation Scheme

AbstractA field study evaluating wetted radius (Wr), downward depth (Dd), and upward movement (Um) under different emitter discharges and lateral depths was conducted. Four emitter discharges (2, 4, 8, and 16 L/h) and four lateral depths (0, 10, 20, and 30 cm) were tested in a clay loam soil. Relationships were found between the emitter discharge and lateral depth versus Wr, Dd, and Um. Wetting area at the surface occurs under different emitter discharges and lateral depths except at 30 cm lateral depth. At lateral depth of 0 and 10 cm, Wr and emitter discharge were positively correlated. The Dd was not affected by emitter discharge except for laterals installed at 20 cm depth. At 30 cm lateral depth, the correlations between each of Wr, Um, and Dd with emitter discharge were poor. The ratios of Wr/Dd and Um/Dd, with respect to emitter position, were less than unity over different emitter discharges and lateral depths. These results shed some light on the design of subsurface drip irrigation scheme so that the spacing between emitters should be determined based on the lateral depths and discharge of emitters. Evaporation losses were negligible for the 30‐cm‐lateral depth since the upward moisture movement has not reached the soil surface area at all discharge rates tested in the study.

Low-lying thyroglossal duct cyst with lateral cervical discharge masquerading as a second branchial cleft fistula: a case report

The diagnosis of a thyroglossal duct cyst is often apparent when it presents with typical findings. We report a case of a 6year-old girl with a low-lying thyroglossal duct cyst presenting with recurrent lateral cervical discharge without palpable mass, thus mimicking a second branchial cleft fistula. CT scan differentiated the lesion from a second branchial cleft fistula, and a standard Sistrunk procedure cured the lesion. In patients who show lateral cervical discharge without definite mass, therefore mimicking a second branchial cleft fistula, a low-lying thyroglossal duct cyst should be considered.

Effect of metal coating on machinability of high purity germanium using wire electrical discharge machining

This paper reports on the research of wire electrical discharge machining (WEDM) as a cutting process for n-type high purity germanium (HP Ge). WEDM requires sufficient electrical conductivity of the work piece for discharges to occur. Owing to the very high material resistivity of HP Ge (32.8Ωcm), the electrical conduction is too low for WEDM to be efficient. To temporarily enhance the conduction, metals (aluminum and nickel) were deposited on the HP Ge on 1 or 2 sides with various thicknesses (1.0, 2.0, and 3.0μm) using sputter deposition. This shortens the path of conduction between the HP Ge and the WEDM ground and also serves to trigger the discharges. Machining experiments were performed to determine the correlation between the slicing rate and locally enhanced HP Ge through various discharge energies (potential voltage: 150, 200, 250 and 300V and capacitance: 1, 3.3, 5.5, 9.9 and 21.4nF). From the results, the obtained maximum slicing rate is 7.7mm2/min for Al coating (2 sides, 1.0μm thickness) at high energy (300V, 21.4nF), which is improved as much as 27 times over uncoated HP Ge. The fastest cutting without creating subsurface microcracks was measured as 1.12mm2/min performed at 150V and 9.9nF. Additional slicing experiments at reverse polarity (positive wire and negative work piece, uncommon polarity for WEDM) were performed at 150V and various capacitances. The experiment proved that there were rectifying contacts at the metal coating surface. It was found that under identical EDM settings, a faster slicing rate also showed a reduction in kerf size due to less lateral discharge energy. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used to investigate microcracks and to analyze surface impurities.

A COUPLED KARST-POROUS GROUNDWATER MODEL BASED ON THE ADAPTED GENERAL HEAD BOUNDARY

Groundwater in karst aquifer and porous aquifer always have close hydraulic connection. However, groundwater in karst aquifer always behaves as turbulent flow, while the porous groundwater flows in a laminar way. Due to the different flow properties, it is difficult to simulate the connection between the two types of groundwater simultaneously, in one model. This paper aims at designing a coupled model which is able to describe the hydraulic connection between the karst and porous groundwater system. The MODFLOW is applied on the porous groundwater modeling, while a tank model is employed to simulate the karst groundwater system. An Adapted General Head Boundary (AGHB) is designed to couple the MODFLOW and the tank model. The Taiyuan City is taken as the typical study case to evaluate the coupled model. The result shows: (1) the coupled model based on AGHB has satisfied performance for porous groundwater modelling; (2) with AGHB, the karst groundwater head (an unknown variant in general head boundary) could be modeled by the tank model according to the recharge and artificial discharge. The coupled model could simulate the head dynamic of karst groundwater and the lateral discharge automatically; (3) the computation cost of the coupled model is slightly larger than the pure porous model solved by MODFLOW.

The role of bedrock groundwater in rainfall–runoff response at hillslope and catchment scales

► We monitor storm response in bedrock groundwater tables in two headwater catchments. ► Bedrock groundwater did not rise above the soil–bedrock interface. ► Bedrock groundwater responded rapidly to storm events. ► Bedrock geology has considerable impact on hillslope rainfall–runoff response. Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at quantifying bedrock groundwater contributions to hillslope flow and catchment runoff. We present results from the Maimai M8 research catchment in New Zealand and Watershed 10 (WS10) at the H.J. Andrews Experimental Forest in Oregon, USA. Analysis of bedrock groundwater at Maimai, through a range of flow conditions, revealed that the bedrock water table remained below the soil–bedrock interface, indicating that the bedrock aquifer has minimal direct contributions to event-based hillslope runoff. However, the bedrock water table did respond significantly to storm events indicating that there is a direct connection between hillslope processes and the underlying bedrock aquifer. WS10 groundwater dynamics were dominated by fracture flow. A highly fractured and transmissive zone within the upper one meter of bedrock conducted rapid lateral subsurface stormflow and lateral discharge. The interaction of subsurface stormflow with bedrock storage directly influenced the measured hillslope response, solute transport and computed mean residence time. This research reveals bedrock groundwater to be an extremely dynamic component of the hillslope hydrological system and our comparative analysis illustrates the potential range of hydrological and geological controls on runoff generation in headwater catchments.

Intérêt de l’expansion pour la fermeture cutanée des larges myéloméningocèles

Closure of a large myelomeningocele requires stable durable coverage of the dural reconstruction. Twenty-seven cases of myelomeningoceles have been treated in the department of pediatric neurosurgery at the Timone Children's Hospital in the last 17 years. Six children have undergone plastic and reconstructive surgery. Among these six children, four were received several months after birth with a large myelomeningocele and underwent cutaneous expansion prior to closure. One child received lateral discharge incisions during the neonatal period. The sixth child, received at 15 years of age for persistent CSF leak despite numerous attempts to close the dura, was treated by rotational dorsal fasciocutaneous flap with dural plastic surgery. In all of the cases, these techniques provided stable and durable closure with a maximum follow-up of 11 years. An expansion complication was observed with exposure of the prosthesis without secondary infection. Cutaneous expansion is the technique of choice for late closure of large myelomeningoceles. It makes it possible to limit wound-healing problems and preserve muscle and skin resources in children who risk pressure sores.

Sensitivity analysis of groundwater level in Jinci Spring Basin (China) based on artificial neural network modeling

Jinci Spring in Shanxi, north China, is a major local water source. It dried up in April 1994 due to groundwater overexploitation. The groundwater system is complex, involving many nonlinear and uncertain factors. Artificial neural network (ANN) models are statistical techniques to study parameter nonlinear relationships of groundwater systems. However, ANN models offer little explanatory insight into the mechanisms of prediction models. Sensitivity analysis can overcome this shortcoming. In this study, a back-propagation neural network model was built based on the relationship between groundwater level and its sensitivity factors in Jinci Spring Basin; these sensitivity factors included precipitation, river seepage, mining drainage, groundwater withdrawals and lateral discharge to the associated Quaternary aquifer. All the sensitivity factors were analyzed with Garson’s algorithm based on the connection weights of the neural network model. The concept of “sensitivity range” was proposed to describe the value range of the input variables to which the output variables are most sensitive. The sensitivity ranges were analyzed by a local sensitivity approach. The results showed that coal mining drainage is the most sensitive anthropogenic factor, having a large effect on groundwater level of the Jinci Spring Basin.

Adjusted friction correction factors for center-pivots with an end-gun

A new method for calculating total friction head loss in center-pivots with an operational end-gun was developed. The proposed methodology is based on adjusting the previous friction correction factors for center-pivots with end-guns in order to correct their paradoxes and shortcomings. Equations presented in the current work are developed for center-pivots with a finite number of outlets along the lateral and constant outlet spacing and discharge as well as constant discharge and variable spacing. The proposed formulas depend on the number of outlets along the supply pipeline, the exponent of velocity term in the friction formula used and the distance that water is jetted by the end-gun. All equations reduce to the well-established equations for the friction correction factor when the end-gun is turned off. The equations presented here compare well to the stepwise friction calculation method, yet correct slight errors in the way that these friction correction factors were calculated in the past.

Compatibility Assessment of Drip Irrigation Laterals

Emitters inserted in drip irrigation laterals cause local head loss, generally estimated as a product of a coefficient and the velocity head. This local head loss coefficient and the emitter discharge curve hydraulic parameters may exhibit considerable variability attributable to the manufacturing process. This paper provides a framework for assessing whether the variability in the hydraulic parameters could lead to significant differences in the performance of rolls of drip irrigation laterals from the same manufacturing batch. A system approach with inlet pressure as input, pressure distribution along the drip lateral and inlet discharge as outputs (or responses), and a drip lateral hydraulic model as the transfer function is explored. Within a Bayesian statistical framework of parameter uncertainty based on the Metropolis algorithm, the hydraulic parameters of pressure-compensating drip lateral rolls from the same manufacturing batch were inferred (calibrated). Overlapping of the space (region) of the ...

Asymmetric fluxes of water and sediments in a mesotidal mudflat channel

The hydrodynamics of a small tributary channel and its adjacent mudflat is studied in Willapa Bay, Washington State, USA. Velocity profiles and water levels are simultaneously measured at different locations in the channel and on the mudflat for two weeks. The above tidal flat and channel hydrodynamics differ remarkably during the tidal cycle. When the water surface level is above the tidal flat elevation, the channel is inactive. At this stage, the above tidal flat flow is predominantly aligned along the Bay axis, oscillating with the tide as a standing wave with peak velocities up to 0.3 m/s. When the mudflat becomes emergent, the flow concentrates in the channel. During this stage, current velocities up to 1 m/s are measured during ebb; and up to 0.6 m/s during flood. Standard equations for open-channel flow are utilized to study the channel hydrodynamics. From the continuity equation, a lateral inflow is predicted during ebb, which likely originates from the drainage of the mudflat through the lateral runnels. Both advective acceleration and lateral discharge terms, estimated directly from the velocity profiles, play a significant role in the momentum equation. The computed drag coefficient for bottom friction is small, due to an absence of vegetation and bottom bedforms in the channel. Sediment fluxes are calculated by combining flow and suspended sediment concentration estimated using the acoustic backscatter signal of the instruments. A net export of the sediment from the channel is found during ebb, which is not balanced by the sediment import during flood. When the mudflat is submerged, ebb-flood asymmetries in suspended sediment concentration are present, leading to a net sediment flux toward the inner part of the Willapa Bay. Finally, a residual flow is detected inside the channel at high slack water, probably associated with the thermohaline circulation.

GABAergic neurons intermingled with orexin and MCH neurons in the lateral hypothalamus discharge maximally during sleep

The lateral hypothalamus (LH), where wake-active orexin (Orx)-containing neurons are located, has been considered a waking center. Yet, melanin-concentrating hormone (MCH)-containing neurons are codistributed therein with Orx neurons and, in contrast to them, are active during sleep, not waking. In the present study employing juxtacellular recording and labeling of neurons with Neurobiotin (Nb) in naturally sleeping-waking head-fixed rats, we identified another population of intermingled sleep-active cells, which do not contain MCH (or Orx), but utilize gamma-aminobutyric acid (GABA) as a neurotransmitter. The 'sleep-max' active neurons represented 53% of Nb-labeled MCH-(and Orx) immunonegative (-) cells recorded in the LH. For identification of their neurotransmitter, Nb-labeled varicosities of the Nb-labeled/MCH- neurons were sought within sections adjacent to the Nb-labeled soma and immunostained for the vesicular transporter for GABA (VGAT) or for glutamate. A small proportion of sleep-max Nb+/MCH- neurons (19%) discharged maximally during slow-wave sleep (called 'S-max') in positive correlation with delta electroencephalogram activity, and from VGAT staining of Nb-labeled varicosities appeared to be GABAergic. The vast proportion of sleep-max Nb+/MCH- neurons (81%) discharged maximally during paradoxical sleep (PS, called 'P-max') in negative correlation with electromyogram amplitude, and from Nb-labeled varicosities also appeared to be predominantly GABAergic. Given their discharge profiles across the sleep-wake cycle, P-max together with S-max GABAergic neurons could thus serve to inhibit other neurons of the arousal systems, including local Orx neurons in the LH. They could accordingly dampen arousal with muscle tone and promote sleep, including PS with muscle atonia.

Understanding sub-surface solute distributions and salinization mechanisms in a tropical coastal floodplain groundwater system

The Burdekin coastal floodplain aquifer is a tropical groundwater system exploited for irrigated agriculture that has exhibited increases in groundwater salinity since regular monitoring was introduced in the 1960s. Evapotranspiration of irrigation water, displacement of unsaturated zone solutes, enhanced mixing with relict seawater and seawater intrusion are mechanisms considered to explain the observed increase. The floodplain aquifer is comprised of complex successions of Quaternary terrigenous and marine sediments hosting groundwater with Cl− concentrations from <50 mg/l to >50,000 mg/l. The lowest salinity groundwater is found adjacent to the Burdekin River and within palaeochannels dissecting the floodplain. Cl− concentrations <100 mg/l, together with NO3-/Cl mass ratios >0.1 indicate the fresh groundwater originates from vertical infiltration of rainwater and irrigation water entrained with agricultural nitrogen through the coarse-grained palaeochannel sediments. Na/Cl ratios similar to the Burdekin River indicate that lateral discharge from the river channel to the floodplain aquifer also accounts for the distribution of low-salinity groundwater. Tidal and near-shore marine sediments deposited during Pleistocene and Holocene high sea level stands host highly saline groundwater (Cl− 20,000–80,000 mg/l) up to 15 km inland. In many areas of the floodplain, nested piezometer locations reveal older, more saline water at depth. Na and Cl− concentrations of more than 8000 floodplain groundwater samples collected over a 40 yr period fall on a mixing line between river water/fresh groundwater and modern/relict seawater indicating that intermediate salinity waters have evolved over time through varying degrees of mixing between the two end-member compositions. Temporal trends in Na and Cl− concentrations indicate that increases in groundwater salinity across the floodplain are primarily due to this mixing process, and that evapotranspiration from irrigated crops and displacement of unsaturated zone solutes has had less of an effect. This salinization process, which includes displacement of relict seawater within the aquifer and seawater intrusion, is likely exacerbated by extraction from >1400 production bores and enhanced recharge across the floodplain. Halting and reversing the ongoing groundwater salinization will require a mixture of setting and meeting local and regional groundwater targets (water table depths and groundwater quality), and where needed implementing appropriate deep drainage and drainage disposal management strategies.