Oscillatory well pumping was proposed recently as a tool for hydraulic tomography. Periodic pumping at a few frequencies is carried out through vertical intervals along the pumping well and the periodic head is measured along a few piezometers. The paper presents an analytical solution for the head field in an unconfined aquifer of finite depth under the common assumptions of a linearized water...

Recently Pawel Parys [3] pointed out an error in the article “On the structure of graphs in the Caucal hierarchy” [1], which contains two main results: Theorems 15 and 61. Theorem 61 is a pumping lemma for higher-order pushdown automata. The proof consists in two parts: (1) a series of technical lemmas that, given a run of the automaton containing a so-called pumping pair, constructs a longer r...

Articular cartilage is avascular. Nutrients are transported to the cells mainly by diffusion from the synovial fluid. Nutrient transport is also sometimes thought to be assisted by movement of fluid in and out of cartilage in response to cyclic loading of the tissue ('pumping'). The influence of pumping on transport of solutes through cartilage was measured by subjecting plugs of human femoral ...

Photodissociation regions (PDRs) and shocks give rise to conspicuous emission from rotationally and vibrationally excited molecular hydrogen. This line emission has now been studied with ISO and from the ground in great detail. A remarkable discovery has been that toward the Orion outflow and other shock-excited regions, the H2 level populations show a very high excitation component. We suggest...

abstract background: the pressure of consumption spots in eater supply systems is one of the most important hydraulic parameters can be used in optimized management of water distribution networks. since the pressure has some different effects on various parameters of the network management including its hydraulic functions, reliability, stability and leakage, its control is of great importance ...

A variety of established and experimental geophysical techniques was used to measure the vertical distribution of fracture permeability in a 229-meter deep borehole penetrating schist and quartz monzonite near Mirror Lake, New Hampshire. The distribution of fractures in the borehole was determined by acoustic borehole televiewer and other geophysical logs. Fracture permeability was estimated by...

Semiconductor-based quantum dot single-electron pumps are currently the most promising candidates for the direct realization of the emerging quantum standard of the ampere in the International System of Units. Here, we discuss a silicon quantum dot single-electron pump with radio frequency control over the transparencies of entrance and exit barriers as well as the dot potential. We show that o...

Local groundwater in coastal aquifers in Shenzhen has experienced heavy pumping since the 1980s when it began to expand very quickly from a fishing village to a modern city. Meanwhile, large-scale land reclamation was carried out to meet the needs of various urbanization projects. In this paper we analyzed the groundwater from a coastal aquifer system in Shenzhen and examined the evolution of g...

Cleanup of contaminated aquifers by pumping and injection is one of the commonly used approaches for the remediation of groundwater contamination. Contaminant transport travel time in groundwater can be calculated using a method called ‘particle-tracking’ based on advection. The travel time of the contaminants is a highly non-linear and nonconvex function of pumping/injection rates and well loc...

This chapter highlights the importance of the travel time distribution of solutes in aquifers, in order to evaluate the evolution of solutes at pumping wells. This evaluation is important when the solute is a contaminant and when measures are introduced in the groundwater catchment area in order to reduce the solute concentration at a pumping well. When flow and solute transport in the aquifer ...