Pump Location Research Articles

MULTIDIMENSIONAL OPEN SYSTEM FOR VALVELESS PUMPING

In this study, we present a multidimensional open system for valveless pumping (VP). This system consists of an elastic tube connected to two open tanks filled with a fluid under gravity. The two-dimensional elastic tube model is constructed based on the immersed boundary method, and the tank model is governed by a system of ordinary differential equations based on the work-energy principle. The flows into and out of the elastic tube are modeled in terms of the source/sink patches inside the tube. The fluid dynamics of this system is generated by the periodic compress-and-release action applied to an asymmetric region of the elastic tube. We have developed an algorithm to couple these partial differential equations and ordinary differential equations using the pressure-flow relationship and the linearity of the discretized Navier-Stokes equations. We have observed the most important feature of VP, namely, the existence of a unidirectional net flow in the system. Our computations are focused on the factors that strongly influence the occurrence of unidirectional flows, for example, the frequency, compression duration, and location of pumping. Based on these investigations, some case studies are performed to observe the details of the ow features.

Architecture of Chimeric Spheroids Controls Drug Transport.

It is well-established that upregulation of drug efflux pumps leads to multi-drug resistance. Less is known about the role of the architecture of the tumor microenvironment in this process: how the location of pump expressing cells influences drug exposure to cancerous as well as non-cancerous cells. Here, we report a 3D in vitro model of spheroids with mixtures of cells expressing high and low levels of ABCG2, quantifying pump activity by the ability to reject the fluorescent dye Hoechst 33342. With respect to the organization of the mixed spheroids, three different architectures were observed: 1) high-expressing ABCG2 cells located in the spheroid core surrounded by low-expressing cells, 2) high-expressing ABCG2 cells intermixed with low-expressing cells and 3) high-expressing ABCG2 cells surrounding a core of low-expressing cells. When high-expressing ABCG2 cells were in the core or intermixed, Hoechst uptake was directly proportional to the percentage of ABCG2 cells. When high-expressing ABCG2 cell formed an outer coating surrounding spheroids, small numbers of ABCG2 cells were disproportionately effective at inhibiting uptake. Specific inhibitors of the ABCG2 transporter eliminated the effect of this coating. Confocal microscopy of spheroids revealed the location of high- and low-expressing cells, and Hoechst fluorescence revealed that the ABCG2-dependant drug concentration in the cancer microenvironment is influenced by pump expression level and distribution among the cells within a tissue. In addition to providing a 3D model for further investigation into multicellular drug resistance, these data show that the location of ABCG2-expressing cells can control drug exposure within the tumor microenvironment.

The Dependence of ECR-CVD Processing Parameters on Deposition Uniformity of Hydrogenated Amorphous Silicon (a-Si:H) Films

The uniformity improvement of high deposition rate in hydrogenated amorphous silicon (a-Si:H) film deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) is very essential for a large substrate in PV solar industry. In order to improve the uniformity in depositing thin film in large area, the auxiliary magnetic coils were designed and installed in ECR-CVD to modify the distribution of magnetic field. In addition, the dependence of the other ECR-CVD processing parameters such as resonance position, microwave power, working pressure, and substrate temperature were investigated. The results indicated that more uniform a-Si:H film could be obtained when working pressure was decreased. By using finite element analysis, it was found that location of turbo pump would impact gas flow field and this effect would become more significant at high pressure. Increasing microwave power, increasing horizontal gradient of the magnetic field to the substrate, and forming Cusp magnetic field could enhance ECR-CVD deposition uniformity greatly. However, the plasma location and substrate temperature were not major factors affecting a-Si:H film uniformity in ECR-CVD process. Finally, the optimal and the best 3.8% in uniformity could be achieved in 150mm diameter when the ratio of magnetic field strength at wafer edge to wafer center is 215%, working pressure is 1.5 mtorr, microwave power density is 4W/cm2, and substrate temperature is 180°C.

What does hydraulic tomography tell us about fractured geological media? A field study and synthetic experiments

Between 2005 and 2010, Japan Atomic Energy Agency conducted four long-term, independent pumping tests in a fractured granite formation at the Mizunami Underground Research Laboratory (MIU) site in Mizunami city, central Japan. During these tests, drawdowns were monitored at different depths along several deep boreholes. These tests become one of the few, if not the only, hydraulic tomographic survey conducted in the world over thousands of meters in a fractured geologic medium with several fault zones. We analyzed the drawdown-time data set associated with each pumping test independently, and then the data sets from all pumping tests jointly to derive the spatial distributions of hydraulic conductivity (K) and specific storage (Ss) of the medium. These estimated distributions revealed some large-scale high K and low K zones. While the low K zones corroborated well with known low permeable layers and fault based on geological investigations, there were no clear geological features that can be related to the large-scale high K zones. In order to understand and substantiate these high and low K zones, we simulated a hydraulic tomographic survey in a synthetic fractured aquifer, which bears similar geologic features (i.e., formations, fractures, and faults) at the MIU site, with exception that the hydraulic properties, fracture and fault distributions were known exactly. Results of the simulation show that not only are the identified high K zones related to fracture networks connected with pumping and observation locations of each pumping test but also their values reflect the degree of connectivity of the network. Afterward, we investigated the extent of the improvement of characterization of the fault and fractures through the use of deploying dense monitoring intervals and late-time flux measurements.

Optimal Remediation Design of Unconfined Contaminated Aquifers Based on the Finite Element Method and a Modified Firefly Algorithm

Remediation of contaminated sites requires an optimal decision making system to develop remediation techniques in a cost-effective and efficient manner. A coupled simulation–optimization solution approach, based on the finite element method (FEM) and a modified firefly algorithm (MFA), is developed in this study for optimal contaminated groundwater remediation design. A new modified firefly optimization algorithm is proposed by modifying the traditional firefly algorithm in three ways: (i) adding memory, (ii) preventing premature convergence to local optima and thus accelerating the optimization process, and (iii) proposing a new updating formula. Modifications performed in the present study improved the applicability and efficiency of the traditional metaheuristic firefly optimization algorithm, and led the MFA to outperform both its predecessor and conventional optimization methods (e.g., genetic algorithm). A hypothetical, unconfined contaminated field is considered and remediated by considering pump and treat and flushing methods. Pumping rates are considered as design variables while the number of pumps and pump locations, as well as the pumping period, are initially assumed. The coupled simulation-optimization model (FEM-MFA) proposed in this study constitutes an effective way to determine an optimal remediation design for a contaminated aquifer. The results of the present investigation will contribute to improve groundwater management in contaminated aquifers.

GA–GHCA model for the optimal design of pumped sewer networks

In this paper, a hybrid model, GA–GHCA, composed of the genetic algorithm (GA) and the general hybrid cellular automata (GHCA) is proposed for the efficient and effective optimal design of pumped sewer networks with fixed layout. The GHCA model was recently introduced by the authors with considerable success for the optimal design of sewer networks. Two alternative versions of the GA–GHCA model are proposed. In the first approach, the pump locations and the corresponding pumping heads are decided by the GA model, while the diameter and nodal cover depths of the network pipes are optimally determined by the GHCA model considering the predefined pump locations and their pumping heights defined by the GA. In the second model, however, only the pump locations are decided by the GA model and for each GA individual, the network characteristics including the pipe diameters, pipe nodal cover depths, and the pumping heights at the predefined locations are determined by the GHCA model. The proposed GA–GHCA model is tested against a benchmark example of pumped sewer network and the results are presented and compared to those of the existing methods. The results indicate that the proposed method is more efficient and effective than alternative methods for the optimal design of pumped sewer networks.

Transport simulations of linear plasma generators with the B2.5-Eirene and EMC3-Eirene codes

Linear plasma generators are cost effective facilities to simulate divertor plasma conditions of present and future fusion reactors. The codes B2.5-Eirene and EMC3-Eirene were extensively used for design studies of the planned Material Plasma Exposure eXperiment (MPEX). Effects on the target plasma of the gas fueling and pumping locations, heating power, device length, magnetic configuration and transport model were studied with B2.5-Eirene. Effects of tilted or vertical targets were calculated with EMC3-Eirene and showed that spreading the incident flux over a larger area leads to lower density, higher temperature and off-axis profile peaking in front of the target. The simulations indicate that with sufficient heating power MPEX can reach target plasma conditions that are similar to those expected in the ITER divertor. B2.5-Eirene simulations of the MAGPIE experiment have been carried out in order to establish an additional benchmark with experimental data from a linear device with helicon wave heating.

Sustainable Capture: Concepts for Managing Stream-Aquifer Systems.

Most surface water bodies (i.e., streams, lakes, etc.) are connected to the groundwater system to some degree so that changes to surface water bodies (either diversions or importations) can change flows in aquifer systems, and pumping from an aquifer can reduce discharge to, or induce additional recharge from streams, springs, and lakes. The timescales of these interactions are often very long (decades), making sustainable management of these systems difficult if relying only on observations of system responses. Instead, management scenarios are often analyzed based on numerical modeling. In this paper we propose a framework and metrics that can be used to relate the Theis concepts of capture to sustainable measures of stream-aquifer systems. We introduce four concepts: Sustainable Capture Fractions, Sustainable Capture Thresholds, Capture Efficiency, and Sustainable Groundwater Storage that can be used as the basis for developing metrics for sustainable management of stream-aquifer systems. We demonstrate their utility on a hypothetical stream-aquifer system where pumping captures both streamflow and discharge to phreatophytes at different amounts based on pumping location. In particular, Capture Efficiency (CE) can be easily understood by both scientists and non-scientist alike, and readily identifies vulnerabilities to sustainable stream-aquifer management when its value exceeds 100%.

Reporting of Stream-Aquifer Flow Distribution at the Regional Scale with a Distributed Process-Based Model

Groundwater withdrawals can reduce aquifer-to-stream flow and induce stream-to-aquifer flow. These effects involve potential threats over surface water and groundwater quantity and quality. As a result, the description of stream-aquifer flow in space and time is of high interest for water managers. In this study, the EauDyssee platform, an integrated groundwater/surface water model is extended to provide the distribution of stream-aquifer flow at the regional scale. The methodology is implemented over long periods (17 years) in the Seine river basin (76 375 km2, France) with a 6 481 km long simulated river network. The study scale is compatible with the scale of interest of water authorities, which is often larger than study scales of research projects. Net and gross stream-aquifer exchange flow are computed at the daily time step over the whole river network at a resolution of 1 km. Simulation results highlight that a major proportion of the main stream network (82 %) is supplied by groundwater. Groundwater withdrawals induce a reduction of net aquifer-to-stream flow (−19 %) at the basin scale and flow reversals in the vicinity of pumping locations. Such an integrated model provided at the appropriate regional scale is an essential tool provided to water managers for the implementation of the EU Water Framework Directive.

Pump-probe measurements of the thermal conductivity tensor for materials lacking in-plane symmetry.

We previously demonstrated an extension of time-domain thermoreflectance (TDTR) which utilizes offset pump and probe laser locations to measure in-plane thermal transport properties of multilayers. However, the technique was limited to systems of transversely isotropic materials studied using axisymmetric laser intensities. Here, we extend the mathematics so that data reduction can be performed on non-transversely isotropic systems. An analytic solution of the diffusion equation for an N-layer system is given, where each layer has a homogenous but otherwise arbitrary thermal conductivity tensor and the illuminating spots have arbitrary intensity profiles. As a demonstration, we use both TDTR and time-resolved magneto-optic Kerr effect measurements to obtain thermal conductivity tensor elements of <110> α-SiO2. We show that the out-of-phase beam offset sweep has full-width half-maxima that contains nearly independent sensitivity to the in-plane thermal conductivity corresponding to the scanning direction. Also, we demonstrate a Nb-V alloy as a low thermal conductivity TDTR transducer layer that helps improve the accuracy of in-plane measurements.

Cardiovascular Impacts of High Frequency Chest Compression1

Cardiovascular Impacts of High Frequency Chest Compression1

Assemblies of heat pumps served by a single underground heat exchanger

In this paper we document the relationship between complex flow architecture and global performance for assemblies of heat pumps coupled thermally with the ground through a single U-shaped loop with circulating fluid. The assemblies vary according to heat pump numbers, sizes and locations along the loop. They are classified in a systematic way, and their performance is documented in three classes of designs: assemblies of heat pumps of the same size, heat pumps distributed equidistantly, and large numbers of heat pumps distributed almost continuously on a long loop. The work is based on numerical simulations, and on an analysis that holds in the limit of heat pumps distributed continuously. The relationship between flow architecture and global performance (heat transfer density) serves as guide for the energy design of high-density urban settlements in the future.

Hydraulic tomography offers improved imaging of heterogeneity in fractured rocks.

Fractured rocks have presented formidable challenges for accurately predicting groundwater flow and contaminant transport. This is mainly due to our difficulty in mapping the fracture-rock matrix system, their hydraulic properties and connectivity at resolutions that are meaningful for groundwater modeling. Over the last several decades, considerable effort has gone into creating maps of subsurface heterogeneity in hydraulic conductivity (K) and specific storage (Ss ) of fractured rocks. Developed methods include kriging, stochastic simulation, stochastic inverse modeling, and hydraulic tomography. In this article, I review the evolution of various heterogeneity mapping approaches and contend that hydraulic tomography, a recently developed aquifer characterization technique for unconsolidated deposits, is also a promising approach in yielding robust maps (or tomograms) of K and Ss heterogeneity for fractured rocks. While hydraulic tomography has recently been shown to be a robust technique, the resolution of the K and Ss tomograms mainly depends on the density of pumping and monitoring locations and the quality of data. The resolution will be improved through the development of new devices for higher density monitoring of pressure responses at discrete intervals in boreholes and potentially through the integration of other data from single-hole tests, borehole flowmeter profiling, and tracer tests. Other data from temperature and geophysical surveys as well as geological investigations may improve the accuracy of the maps, but more research is needed. Technological advances will undoubtedly lead to more accurate maps. However, more effort should go into evaluating these maps so that one can gain more confidence in their reliability.

정수장 내 축열조 설치 원수열원 히트펌프의 성능분석

정수장 내 축열조 설치 원수열원 히트펌프시스템의 동적 특성을 TRNSYS 프로그램을 이용하여 모델링 하였다. 원수열원 히트펌프의 실증평가를 위해 성남정수장 내 축열조가 설치된 히트펌프 실험결과를 이용하여 검증하였고, 본 설비는 2010년 11월부터 운전되고 있다. 모델링 결과 원수열원 히트펌프의 평균 COP는 냉·난방 시 각각 4.97과 3.17을 나타냈다. 축열조 용량은 5㎥에서 20㎥로 변화시킬 때, 축열조 용량 10㎥ 에서 가장 높은 COP와 소비전력이 나타났다. 설치지역으로 서울, 인천, 강릉, 그리고 광주를 고려하였고, 지역에 따른 COP와 소비전력은 큰 변화가 없었으나 소비전력량에 있어서 난방 시에 위도가 높은 서울의 소비전력량이 가장 높으며, 냉방 시에 가장 낮게 나타났다. 본 시스템을 동일한 용량의 물-공기방식의 히트펌프와 비교할 때 평균 25%정도 낮은 소비전력량을 나타냈다.

A SENSOR WEB MODEL AND WEB SERVICE FOR DRINKING WATER DISTRIBUTION MANAGEMENT

Population growth, energy demand, and climate change are placing an unprecedented strain on water resources, requiring a fundamental shift in how these resources are managed. Since water distribution systems are highly vulnerable to leakages, improper usage, incidents of contamination, accidental or purposeful intrusions, considerable attention is required for prompt action to save and optimum utilization of natural resource of drinking water. Due to spread out and remote locations of Water supply tanks and Pumps/ Valves, both the storage and availability of Water as well as distribution control are difficult. Dependence on Pump attendants makes a mockery of Supply system of this most critical commodity. An approach of Wireless Sensor Network (WSN) application to do real- time data collection at the water supply sources such as water tanks , valves/outlets and etc., to obtain proper required parameters measuring to optimize water resource management . The Sensor Web is an emerging technology that promises to revolutionize the way water information is collected and disseminated. A Sensor Web is a group of interoperable web services, which all comply with a specific set of information models and interface specifications. The Open Geospatial Consortium (OGC) is developing information models and service interface specifications for Sensor Web Enablement (SWE)

Anatomy of the foot venous pump: physiology and influence on chronic venous disease

The aim of this paper is to demonstrate the location of the venous foot pump using an anatomical study. Four hundred cadaveric feet were injected with green neoprene latex followed by a dissection. A coloured segmentation of the venous system was achieved. The Lejars' concept of the venous sole of the foot is incorrect: the true blood venous reservoir of the foot is located deeply in the plantar veins, between the plantar muscles. The medial and mostly lateral plantar veins converge into the plexus shaped calcaneal crossroad, where the blood is ejected upwards into the two posterior tibial veins. In addition, the several medial perforators of the foot directly connect the deep system (medial plantar veins) to the superficial venous system (medial marginal vein). This forms a true 'medial functional unit' which is unique in the limb given its directional flow is from deep to superficial. In conclusion, the plantar veins play an important role in the physiology of the venous return since a venous reservoir of 25 mL of blood is mobilized upwards with each step during walking. Therefore, the impairment of the foot pump by a static foot disorder should be considered as an important risk factor for chronic venous disease, and should be evaluated and corrected in any patient with venous insufficiency.

Simulation of a convective loop for the Nested Thermal Envelope Design™ low-energy house

The Nested Thermal Envelope Design™ is an innovative low-energy house design that incorporates two thermal envelopes to create a core and perimeter zone. The perimeter acts as a thermal buffer zone, where heat loss from the core and solar gain in the perimeter are recovered to the core via an inter-zone heat pump. To optimize heat recovery from the perimeter and minimize temperature stratification, a complete loop is formed around the core living space, through which air may flow in a convective loop. A simplified convective loop was modelled with a commercial computational fluid dynamics software package. The results show that the convective loop distributes solar gains and reduces temperature stratification in the perimeter. The location of the heat pump in the convective loop was found to affect the heat pump’s coefficient of performance by up to 21%.

Optimization of Water Systems with the Consideration of Pressure Drop and Pumping

Novel automated design method has been developed to consider impacts of pressure drop and pumping arrangement in the water network in which water reuse is exploited to reduce freshwater consumption in process industries. A superstructure-based optimization framework has been developed to systematically consider all the key design issues simultaneously, including flow rate constraints, pressure-drop constraints, and other operational constraints, as well as to fully accommodate rigorous economic trade-off between freshwater cost, piping cost, and pumping cost. The proposed optimization study enables the identification of the optimal distribution of water within the network, together with the most appropriate location and capacity of pumps required for water systems. A robust and reliable solution strategy has been developed to effectively deal with computational difficulties associated with solving a mixed-integer nonlinear programming problem, with the aid of the effective application of physical insights gained from conceptual understanding of the design problem. The network complexity has been readily controlled by imposing design constraints in the optimization. Examples have been provided to prove the effectiveness of the design method developed in this paper and to demonstrate the importance of considering pressure drop constraints in practice.

Near-field investigation of THz surface-wave emission from optically excited graphite flakes

THz emission from an unbiased graphite flake after optical sub-ps pulse inter-band excitation is measured using a novel micro-machined photoconductive probe-tip. Oscillatory behavior of the measured THz near-field emission is shown to originate from electromagnetic eigenmode resonances of the laterally limited graphite flake. The excitation efficiency of the lowest order eigenmode resonances strongly dependents on optical pump location. From this data a radial symmetric charge carrier translocation at the pump location is revealed as the dominating THz surface-wave emission effect. Measurements show good agreement with numerical field simulations of the eigenmode center frequencies and the spectral response expected for THz emission through basal plane oriented radial current surge excitation.

Controls on initiation and propagation of pumping-induced earth fissures: insights from numerical simulations

Pumping-induced earth fissuring occurs in many localities and represents an important economic problem associated with damage to infrastructures. In this work, a descriptive analysis of the natural conditions of selected localities undergoing fissuring is first performed. Then, numerical simulations are developed using the finite-element code ABAQUS to analyze the evolution of stress induced by pumping that can favor the initiation and propagation of fissures. The scenario used in the numerical simulations is based on the observed features from the descriptive analysis. These natural conditions include a complex stratigraphy, a buried fault scarp and a fault zone cutting the entire sedimentary sequence. Both fault zones and buried fault scarps influence the accumulation of stresses at different times. The fault zone has more influence on the patterns of tension/compression, while the buried fault scarp has more influence on the patterns of shear stress. Results show that a tensile-induced fissure is initiated close to the fault zone in the hanging wall. This fissure originates near the surface and migrates downward, terminating near the saturated–unsaturated interface. Factors involved in the propagation path of the fissure are the occurrence of a fault zone, the location of pumping, and the hydromechanical properties of the vadose zone.