Pump Location Research Articles

Cost-Effective Hydraulic Tomography Surveys for Predicting Flow and Transport in Heterogeneous Aquifers

This study shows how a cost-effective hydraulic tomography survey (HTS) and the associated data estimator can be used to characterize flow and transport in heterogeneous aquifers. The HTS is an improved field hydraulic test that accounts for responses of hydraulic stresses caused by pumping or injection events at different locations of an aquifer. A sequential data assimilation method based on a cokriging algorithm is then used to map the aquifer hydraulic conductivity (K). This study uses a synthetic two-dimensional aquifer to assess the accuracy of predicted concentration breakthrough curves (BTCs) on the basis of the Kfields estimated by geometric mean, kriging, and HTS. Such Kfields represent different degrees of flow resolutions as compared with the synthetically generated one. Without intensive experimentsto calibrate accurate dispersivities at sites, the flow field based on the HTS Kfield can yield accurate predictions of BTC peaks and phases. On the basis of calculating mean absolute and square errors for estimated K fields, numerical assessments on the HTS operation strategy show that more pumping events will generally lead to more accurate estimations of Kfields, and the pump locations need to be installed in high Kzones to maximize the delivery of head information from pumps to measurement points. Additionally, the appropriate distances of installed wells are suggested to be less than one-third of the ln(K) correlation length in x direction.

Investigation of aquifer‐estuary interaction using wavelet analysis of fiber‐optic temperature data

Fiber‐optic distributed temperature sensing (FODTS) provides sub‐minute temporal and meter‐scale spatial resolution over kilometer‐long cables. Compared to conventional thermistor or thermocouple‐based technologies, which measure temperature at discrete (and commonly sparse) locations, FODTS offers nearly continuous spatial coverage, thus providing hydrologic information at spatiotemporal scales previously impossible. Large and information‐rich FODTS datasets, however, pose challenges for data exploration and analysis. To date, FODTS analyses have focused on time‐series variance as the means to discriminate between hydrologic phenomena. Here, we demonstrate the continuous wavelet transform (CWT) and cross‐wavelet transform (XWT) to analyze FODTS in the context of related hydrologic time series. We apply the CWT and XWT to data from Waquoit Bay, Massachusetts to identify the location and timing of tidal pumping of submarine groundwater.

Simulation studies of vacuum system for Indus-2

Due to eight fold symmetry of lattice, the 172.4 meters circumference of Indus-2 was divided into eight unit cells. The location of vacuum pumps was restricted by location of more important components like magnets, beam diagnostic components etc. The minimum permissible beam aperture, restricted by apertures of magnets, rendered the vacuum envelope highly conductance limited. Main sources of gas loads viz the outgassing and the photon induced desorption (PID) were also highly location specific, because of location of photon absorbers, and the specific nature of vacuum components. Therefore, the computer simulation of a unit cell was important to have a feel for ultimate results obtained by a particular configuration of pump installation. The vacuum system for a unit cell was studied using electrical equivalent network for the vacuum system. The entire circuit was analyzed by using commercial software used for electronics circuit analysis. Since the synchrotron radiation leads to cleaning effect and the PID yield reduces with accumulated dose of beam current, system's behaviour with beam current was also studied by using computer program obtained from BESSY Berlin. This provided an estimate of dose necessary for achieving the specified operation of UHV system for Indus-2. The calculations also helped in optimizing the initial cleaning of chambers by glow discharge cleaning etc. This paper presents the results obtained by computer simulations of a unit cell of Indus-2, carried out by both the methods.

Na+–K+ pump location and translocation during muscle contraction in rat skeletal muscle

Muscle contraction may up-regulate the number of Na(+)-K(+) pumps in the plasma membrane by translocation of subunits. Since there is still controversy about where this translocation takes place from and if it takes place at all, the present study used different techniques to characterize the translocation. Electrical stimulation and biotin labeling of rat muscle revealed a 40% and 18% increase in the amounts of the Na(+)-K(+) pump alpha(2) subunit and caveolin-3 (Cav-3), respectively, in the sarcolemma. Exercise induced a 36% and 19% increase in the relative amounts of the alpha(2) subunit and Cav-3, respectively, in an outer-membrane-enriched fraction and a 41% and 17% increase, respectively, in sarcolemma giant vesicles. The Na(+)-K(+) pump activity measured with the 3-O-MFPase assay was increased by 37% in giant vesicles from exercised rats. Immunoprecipitation with Cav-3 antibody showed that 17%, 11% and 14% of the alpha(1) subunits were associated with Cav-3 in soleus, extensor digitorum longus, and mixed muscles, respectively. For the alpha(2), the corresponding values were 17%, 5% and 16%. In conclusion; muscle contraction induces translocation of the alpha subunits, which is suggested to be caused partly by structural changes in caveolae and partly by translocation from an intracellular pool.

Efficient and Practical Approaches to Ground‐Water Right Transfers Under the Prior Appropriation Doctrine and the Snake River Example1

Abstract: Water right transfers are one of the basic means of implementing changes in water use in the highly appropriated water resource systems of the western United States. Many of these systems are governed by the Prior Appropriation Doctrine, which was not originally intended for application to ground‐water pumping and the conjunctive management of ground water and surface water, and thus creates an administrative challenge. That challenge results from the fact that ground‐water pumping can affect all interconnected surface‐water bodies and the effects may be immeasurably small relative to surface water discharge and greatly attenuated in time. Although we may have the ability to calculate the effects of ground‐water pumping and transfers of pumping location on surface‐water bodies, mitigating for all the impacts of each individual transfer is sufficiently inefficient that it impedes the transfer process, frustrates water users, and consequently inhibits economic development. A more holistic approach to ground‐water right transfers, such as a ground‐water accounting or banking scheme, may adequately control transfer third‐party effects while reducing mitigation requirements on individual transfers. Acceptance of an accounting scheme can accelerate the transfer process, and possibly reduce the administrative burden.

The Cleveland Clinic PediPump: Anatomic Modeling and Virtual Fitting Studies in a Lamb Model

Implantation of ventricular assist devices (VADs) is challenging in small patients with limited space in the chest. We created three-dimensional models of lambs to facilitate fitting of the PediPump, a pediatric VAD currently under development. Serial computed tomography (CT) scans were acquired at multiple time points (n = 8) for three lambs. Digital models were created using these CT datasets and three-dimensional image processing software (Mimics, Materialise). Pixels representing the heart and chest wall were rendered as three-dimensional models. Using three-dimensional model manipulation software (Magics RP, Materialise), on-screen models of extravascular and intravascular VADs were placed in right, left and biventricular support configurations to determine optimal placement. A cannulation strategy was established and in some cases three-dimensional models of the inflow and outflow grafts were created. After the final CT study, an open-chest fitting study was performed using rapid prototype models of the pediatric VAD and cannulas. The pump location and orientation predictions from the virtual fitting studies matched those determined at the time of the open-chest fitting studies. Using three-dimensional modeling, we have established a fitting protocol that facilitates animal implantations; the same modeling techniques may be useful for device fitting in humans.

Investigation into pressure pulsations in a centrifugal pump using numerical methods supported by industrial tests

The operation of centrifugal pumps can generate instabilities and pressure pulsations that may be detrimental to the integrity and performance of the pump. In the present study a numerical investigation of the time variation of pressure within a complete centrifugal pump was undertaken. A range of parameters and three flow rates were investigated and the pulsations were extracted at 15 different locations covering important pump regions. The transient flow results compared reasonably with experimental data obtained in a limited experimental survey and clearly indicated the pump locations experiencing the largest pulsation levels. It was also noted that monitoring pulsations at the top dead centre of the pump volute casing would provide a better indication of internal pump pulsations than monitoring at the discharge.

Cleveland Clinic PediPump Lamb Cadaver Fitting Studies

We are developing the PediPump, a magnetically suspended, mixed-flow pump, as an implantable pediatric ventricular assist device (VAD). Lamb cadaver fitting studies were performed to determine the optimal pump location and optimal design of the inflow and outflow conduits for chronic in vivo studies. A prototype of the PediPump right and left ventricular assist devices (RVAD and LVAD, respectively) were implanted via a sternotomy or left thoracotomy in four lamb cadavers (3.7-34.2 kg). Via a sternotomy, the RVAD and LVAD required long inflow cannulas when placed into the right or left thoracic cavities, respectively. Via a left thoracotomy, with both pumps implanted in the left thoracic cavity, the RVAD required a 70 degrees inflow cannula and a bent outflow graft while the LVAD required a 130 degrees inflow cannula and a straight outflow graft. In conclusion, left thoracotomy provided optimal fitting for both LVAD and RVAD for the small lamb model.

Optimal pumping locations of skimming wells

A real-life problem involving pumping of groundwater from a series of existing wells along a river flood plain underlain with geologically saline water is examined within a conceptual framework. Unplanned pumping results in upconing of saline water. Therefore, it is necessary to determine optimal locations of fixed capacity pumping wells in space and time from a set of pre-selected candidate wells that minimize total salinity concentration in space and time. The nonlinear, non-convex, combinatorial problem involving zero—one decision variables is solved in a simulation—optimization (S/O) framework. Optimization is accomplished by using simulated annealing (SA)—a search algorithm. The computational burden is primarily managed by replacing the numerical model with a surrogate simulator—artificial neural network (ANN). The computational burden is further reduced through intuitive algorithmic guidance. The model results suggest that the skimming wells must be operated from optimal locations such that they are staggered in space and time to obtain least saline water.

Computational Design and Experimental Testing of a Novel Axial Flow LVAD

Thousands of cardiac failure patients per year in the United States could benefit from long-term mechanical circulatory support as destination therapy. To provide an improvement over currently available devices, we have designed a fully implantable axial-flow ventricular assist device with a magnetically levitated impeller (LEV-VAD). In contrast to currently available devices, the LEV-VAD has an unobstructed blood flow path and no secondary flow regions, generating substantially less retrograde and stagnant flow. The pump design included the extensive use of conventional pump design equations and computational fluid dynamics (CFD) modeling for predicting pressure-flow curves, hydraulic efficiencies, scalar fluid stress levels, exposure times to such stress, and axial fluid forces exerted on the impeller for the suspension design. Flow performance testing was completed on a plastic prototype of the LEV-VAD for comparison with the CFD predictions. Animal fit trials were completed to determine optimum pump location and cannulae configuration for future acute and long-term animal implantations, providing additional insight into the LEV-VAD configuration and implantability. Per the CFD results, the LEV-VAD produces 6 l/min and 100 mm Hg at a rotational speed of approximately 6300 rpm for steady flow conditions. The pressure-flow performance predictions demonstrated the VAD's ability to deliver adequate flow over physiologic pressures for reasonable rotational speeds with best efficiency points ranging from 25% to 30%. The CFD numerical estimations generally agree within 10% of the experimental measurements over the entire range of rotational speeds tested. Animal fit trials revealed that the LEV-VAD's size and configuration were adequate, requiring no alterations to cannulae configurations for future animal testing. These acceptable performance results for LEV-VAD design support proceeding with manufacturing of a prototype for extensive mock loop and initial acute animal testing.

River sediment salt-load detection using a water-borne transient electromagnetic system

The salinisation of major river systems in Australia, and in other countries, is primarily determined by the upward movement of saline water from regional aquifers into the river. The migration has been accelerated due to irrigation schemes and farming practices that have changed regional hydraulic gradients driving saline-water in aquifers towards the major drainage points in the landscape. In this paper, we describe results from a transient electromagnetic (TEM) system that has been deployed to monitor the influx of saline water through sub-riverbed sediments. The deployment was a floating arrangement of a commercial fast sampling (high resolution) TEM system that is sensitive to shallow (< 50 m depth) resistivity variations. The technique has been extensively trialed around the River Murray town of Waikerie in South Australia. An initial series of surveys along a 40 km section of river showed a range of sub-riverbed resistivities between 1 and 20 Ωm, with a top layer of about 10–15 Ωm closely following the water depth. Regions of high-resistivity in the riverbed sediments correlated well with saline-aquifer borehole pumping locations, indicating a localized drawdown of fresher river water. Low-resistivity anomalies have been interpreted as regions of saline water influx into the river. The technique is now used for routine mapping in Australia, with over 800 km of the Murray surveyed, and has potential application to other major world river systems.

Managing groundwater rise: Experimental results and modelling of water pumping from a quarry lake in Milan urban area (Italy)

An innovative approach to solve the problem of lowering water table was carried out in a quarry lake south of the city of Milan (northern Italy): the project, based upon pumping out water at a rate of 1,000 L/s can be considered a strategic medium to long-term solution to hinder the rise of groundwater level interfering with underground structures (foundation, construction, subway) in urban areas. The basic idea is to pump a high groundwater rate as close as possible to the stagnation point of the piezometric depression located in the city. After a pilot-test was carried out in November 1998, experimental activities started in July 2001 and lasted one year; water withdrawal was discharged into artificial channels used in agricultural practice. Maximum drawdowns measured in the quarry lake by the monitoring network resulted in more than 5 m, and a significant drawdown was registered up to 1.5 km of distance from the quarry in the important historical site of Chiaravalle Abbey, threatened by groundwater rise. The results of this pumping activity confirm the importance of the project, its lower cost compared with traditional solutions (such as drainage by wells) and remarkable effects on the improvement of surface water quality. A groundwater model was implemented to evaluate further scenarios of discharge rate and pumping location, too.

소규모유역의 수치모헝을 이응한 지하수 유동해석

The applied model for this study area is WINFLOW using mite element method, It is thought that the simulation result by WINFLOW model under the steady flow state reflects well the ground water distribution within the reliability level which shows the error range of 1.1% to 8.0% from the comparison between the computed values and the observed, and analyzed that the constant head distribution is shown along the east-west direction and gentle and stable head gradient along the north-south direction. Ground water of the study area shows stable movement from the south to the stream area, and the particle trace for each location shows relatively linear shape from the upstream to the pumping location while the radius of influence according to the pumping amount shows a significant difference at the down stream area from the pumping location. The simultaneous pumping from P and P1 shows more complicated appearance, not the increase of the radius of influence than pumping from a single well P or P1, and it is analyzed that the particle path takes nearly linear form. It is known that the flow direction of the ground water and the velocity of the flow affect on the magnitude of the radius of influence of the wells from the fact that the more decreasing pattern of the ground water head is observed at the side of the well and the down stream area than the upstream area when the ground water moves from south to north regarding the radius of influence according to the pumping amount. Satisfactory results in analyses of ground water movement are obtained through the significant reduction of the physical uncertainties in the flow system as well as the relatively convenient model application using WINFLOW model which is proposed in this study.

Selective Excitation of Localized Modes in Active Random Media

Laser action in the regime of Anderson localization is investigated by coupling Maxwell's equations in a strongly scattering medium with the rate equations of a four-level atomic system. We find that the localized modes of the passive medium are not modified by the presence of gain and serve as resonant microcavities of the random laser. The spectrum of laser emission is shown to depend on the location of the external pump. These results are similar to the recent experimental observations in semiconductor powder [Cao et al., Phys. Rev. Lett. 82, 2278 (1999)]. We show that local pumping of the system allows selective excitation of individual localized modes.

Effect of heterogeneity on radionuclide retardation in the alluvial aquifer near Yucca Mountain, Nevada.

The U.S. Department of Energy is currently studying Yucca Mountain, Nevada, as a potential site for a geological high-level waste repository. In the current conceptual models of radionuclide transport at Yucca Mountain, part of the transport path to pumping locations would be through an alluvial aquifer. Interactions with minerals in the alluvium are expected to retard the downstream migration of radionuclides, thereby delaying arrival times and reducing ground water concentrations. We evaluate the effectiveness of the alluvial aquifer as a transport barrier using the stochastic Lagrangian framework. A transport model is developed to account for physical and chemical heterogeneities and rate-limited mass transfer between mobile and immobile zones. The latter process is caused by small-scale heterogeneity and is thought to control the macroscopic-scale retardation in some field experiments. A geostatistical model for the spatially varying sorption parameters is developed from a site-specific database created from hydrochemical measurements and a calibrated modeling approach (Turner and Pabalan 1999). Transport of neptunium is considered as an example. The results are sensitive to the rate of transfer between mobile and immobile zones, and to spatial variability in the hydraulic conductivity. Chemical heterogeneity has only a small effect, as does correlation between hydraulic conductivity and the neptunium distribution coefficient. These results illustrate how general sensitivities can be explored with modest effort within the Lagrangian framework. Such studies complement and guide the application of more detailed numerical simulations.

Location of an intra-aortic balloon pump

A 75-YEAR-OLD man presenting with unstable angina pectoris after a recent non-Q wave myocardial infarction was scheduled for elective off-pump coronary artery bypass graft surgery. Preoperative investigations revealed triple-vessel coronary artery disease on coronary angiography and hypokinesis of the anterior and inferior left ventricular walls on transthoracic echocardiography.

Pathogenesis of infectious diarrhea.

A brief overview of some of the main features involved in normal physiological bi-directional absorption and secretion of fluid in the gut is given, including the nature and cellular location of key enzymes, ion pumps, symports, antiports and diffusion channels; the microanatomy of intestinal villous vasculature and the dynamics of villus blood flow, which together generate hypertonic zones in villus tip regions; and the production, differentiation, escalator movement (from crypt to villus tip) and subsequent shedding of intestinal epithelial cells. (Neural and hormonal mechanisms that regulate normal mucosal ion transport are not discussed.) The manner in which Vibrio cholerae, several pathotypes of Escherichia coli, several Salmonella serotypes, rotavirus, Campylobacter species, Shigella dysenteriae, Yersinia species and Clostridium difficile perturb these mechanisms and cause diarrhea, is discussed. Throughout the article, the main emphasis is on experimental studies designed to elucidate biological mechanisms and (where relevant) the microbial determinants responsible for diarrheal disease. Allusions are also made to the involvement of host responses such as the inflammatory response, the production and release of potent cytokines and accelerated homeostatic responses (such as increased rates of crypt cell division seen in some infections), and the role that they play in pathophysiological fluid secretion.

Mitigation of Seawater Intrusion by Pumping Brackish Water

This paper presents a technique to restore the balance between freshwater and saline water in coastal aquifers in order to mitigate seawater intrusion problems. Brackish water can be pumped from the dispersion zone and then used to develop green lands in the coastal areas or to irrigate certain types of crops. A two-dimensional finite element model (2D-FED), has been employed to verify this technique. The model is based on the dispersion zone approach with a variable density flow. Simulations were preformed in the vertical view and equiconcentration and equipotential lines were plotted for different locations of brackish water pumping. In all of the tested runs the width of dispersion zone has reduced significantly due to brackish water pumping. The quality of the pumped water differs according to the location of pumping. A study case on the Madras aquifer in India is presented.

Learning from hydrogenases: location of a proton pump and of a second FMN in bovine NADH–ubiquinone oxidoreductase (Complex I)

Hydrogenases have clear evolutionary links to the much more complex NADH–ubiquinone oxidoreductases (Complex I). Certain membrane-bound [NiFe]-hydrogenases presumably pump protons. From a detailed comparison of hydrogenases and Complex I, it is concluded here that the TYKY subunit in these enzymes is a special 2[4Fe–4S] ferredoxin, which functions as the electrical driving unit for a proton pump. The comparison further revealed that the flavodoxin fold from [NiFe]-hydrogenases is presumably conserved in the PSST subunit of Complex I. It is proposed that bovine Complex I and the soluble NAD +-reducing hydrogenase from Ralstonia eutropha each contain a second FMN group.

Hydraulic tomography: Development of a new aquifer test method

Hydraulic tomography (i.e., a sequential aquifer test) has recently been proposed as a method for characterizing aquifer heterogeneity. During a hydraulic tomography experiment, water is sequentially pumped from or injected into an aquifer at different vertical portions or intervals of the aquifer. During each pumping or injection, hydraulic head responses of the aquifer at other intervals are monitored, yielding a set of head/discharge (or recharge) data. By sequentially pumping (or injecting) water at one interval and monitoring the steady state head responses at others, many head/discharge (recharge) data sets are obtained. In this study a sequential inverse approach is developed to interpret results of hydraulic tomography. The approach uses an iterative geostatistical inverse method to yield the effective hydraulic conductivity of an aquifer, conditioned on each set of head/discharge data. To efficiently include all the head/discharge data sets, a sequential conditioning method is employed. It uses the estimated hydraulic conductivity field and covariances, conditioned on the previous head/discharge data set, as prior information for next estimations using a new set of pumping data. This inverse approach was first applied to hypothetical, two‐dimensional, heterogeneous aquifers to investigate the optimal sampling scheme for the hydraulic tomography, i.e., the design of well spacing, pumping, and monitoring locations. The effects of measurement errors and uncertainties in statistical parameters required by the inverse model were also investigated. Finally, the robustness of this inverse approach was demonstrated through its application to a hypothetical, three‐dimensional, heterogeneous aquifer.