The principal mechanisms of Auger recombination of nonequilibrium carriers in semiconductor heterostructures with quantum wells are investigated. It is shown for the first time that there exist three fundamentally different Auger recombination mechanisms of (i) thresholdless, (ii) quasi-threshold, and (iii) threshold types. The rate of the thresholdless Auger process depends on temperature only...

The aim of this work was to compare, from a parasitological ( Cryptosporidium spp. and Giardia duodenalis), bacteriological (total and thermotolerants coliforms) and physicochemical perspective, water sources used for drinking and irrigation of vegetables intended to be sold for human consumption. From January 2010 to May 2011, samples of different water sources from vegetable producing propert...

Compared to vertical or lowinclination wells, horizontal wells can deliver higher production rates, higher recovery factors, and more efficient use of steam in thermally enhanced recovery projects for heavy oil. However, the shallow, thin, and friable sand reservoirs in Columbia’s Girasol field present several challenges to the accurate placement of horizontal wells. Schlumberger was contracted...

Preexisting wells and well bores are high-permeability pathways through the crust, and as such present zones of elevated risk to CO2 storage projects. Although current well closure and abandonment technology appears sufficient to contain CO2 at most sites, individual wells may suffer from a variety of factors that limit their integrity, including improper cementation, improper plugging, overpre...

There are hundreds of thousands of oil and gas wells across North America that are not currently producing oil or gas. Many of these wells have not been permanently decommissioned to meet environmental standards for permanent closure, but left in a inactive state that enables the well to be more easily reactivated. Some of the wells have been temporarily inactive for more than sixty years which...

The decision to perform computed tomography pulmonary angiography (CTPA) to rule out pulmonary embolism (PE) in orthopedic trauma patients is challenging. The Wells score is a commonly used clinical probability tool developed to determine the likelihood of PE and assist in determining the need for CTPA examination. This study evaluated the usefulness of the Wells score for predicting PE in pati...

This paper is the first of a series that attempts to assess the possible health and safety risks associated with large scale CO2 sequestration in deep brine reservoirs. The approach is based on analysis of available data on the operational track record from CO2 transportation and injection associated with enhanced oil recovery (CO2-EOR) in the US. This paper is particularly concerned with ident...

The photorefractive properties of semi-insulating AlGaAs-GaAs multiple quantum wells are described for the transverse Franz-Keldysh geometry with the electric field in the plane of the quantum wells. Combining the strong electroabsorption of quantum-confined excitons with the high resistivity of semi-insulating quantum wells yields large nonlinear optical sensitivities. The photorefractive quan...

In-plane transition-metal dichalcogenides (TMDs) quantum wells have been studied on the basis of first-principles density functional calculations to reveal how to control the electronic structures and the properties. In collection of quantum confinement, strain and intrinsic electric field, TMD quantum wells offer a diverse of exciting new physics. The band gap can be continuously reduced ascri...

A national campaign of well testing through 2003 enabled households in rural Bangladesh to switch, at least for drinking, from high-arsenic wells to neighboring lower-arsenic wells. We study the well-switching dynamics over time by re-interviewing, in 2008, a randomly selected subset of households in the Araihazar region who had been interviewed in 2005. Contrary to concerns that the impact of ...