Search results for "dilution"
showing 10 items of 242 documents
Dense jet modelling applied to the design of dense effluent diffusers
2004
A model aimed at predicting the behavior of inclined dense jets in a stagnant environment was proposed. The model takes into account four jet parameters (flow rate, density, inclination and diameter) and results in a set of algebraic and ordinary differential equations, which are easily solved by simple (standard) numerical methods. Model results include information on the trajectory, spreading and dilution of the inclined dense jets. Model predictions were compared with experimental data obtained with different nozzle diameters, jet flow rates, jet densities and nozzle inclinations. Despite the wide range encompassed by the experimental data analyzed, model predictions were always found to…
Measurement of trace impurities in ultra pure hydrogen and deuterium at the parts-per-billion level using gas chromatography
2018
Abstract A series of muon experiments at the Paul Scherrer Institute in Switzerland deploy ultra-pure hydrogen active targets. A new gas impurity analysis technique was developed, based on conventional gas chromatography, with the capability to measure part-per-billion (ppb) traces of nitrogen and oxygen in hydrogen and deuterium. Key ingredients are a cryogenic admixture accumulation, a directly connected sampling system and a dedicated calibration setup. The dependence of the measured concentration on the sample volume was investigated, confirming that all impurities from the sample gas are collected in the accumulation column and measured with the gas chromatograph. The system was calibr…
A new frozen-spin target for 4π particle detection
1999
Abstract A new frozen-spin target has been developed, that allows the detection of emitted particles in an angular acceptance of almost 4π in the laboratory frame. The central part of this new target represents a 3He/4He dilution refrigerator that is installed horizontally along the beam axis. The refrigerator includes an internal superconducting holding coil to maintain the nucleon polarization in the frozen-spin mode longitudinally to the beam. The design of the dilution refrigerator and the use of an internal holding coil enabled for the first time the measurement of a spin-dependent total cross section in combination with a polarized solid state target. This new frozen-spin target was u…
Sub-kelvin current amplifier using DC-SQUID
2000
Abstract We have set up a system where a low-noise DC-SQUID is used as a current amplifier. The SQUID output is read using a wide band electronics unit based on the noise cancellation scheme. The SQUID has been installed in a compact Nanoway PDR50 dilution refrigerator, and superconducting transitions of Ti/Au thermometer strips for X-ray calorimeter applications have been measured. We can operate at 100 mK using a SQUID with Pd shunt resistors. Noise and bandwidth results of the setup are presented.
Hemodilution in isolated tumor perfusion.
1984
Experiments are performed to study the influence of local hemodilution on tumor blood flow, oxygen availability in tumor tissue and O2 consumption of cancer cells. The results obtained clearly show that hemodilution in isolated tumor perfusion can distinctly improve nutritive blood flow through solid tumors. This can be utilized to enhance pharmacokinetics of antitumor drugs. Due to the improved metabolic status, the pharmacodynamics of some antitumor drugs should also be enhanced. To achieve a maximum improvement of the O2 supply to the tumor, hematocrit values should not be decreased below 0.20.
Spatial characterization of leachate plume using electrical resistivity tomography in a landfill composed of old and new cells (Belfort, France)
2016
International audience; Located near Belfort (France), the Etueffont landfill was in operation from 1976 to 2002 for the disposal and storage of domestic waste produced by 47,650 inhabitants. The site is comprised of the original landfill site called the old landfill (OL), in operation from 1976 to 1999, and a newer section known as the new cell (NC) which operated from 1999 to 2002. The objective of this study is to determine, using electrical resistivity tomography (ERT), the extent of the leachate plume from the OL and to monitor the efficiency of the liner of the NC. The entire Etueffont site was crisscrossed with 21 electrical profile lines which were traced in summer between 2009 and …
Amphiphilic derivatives of a polyaspartamide: their aggregation and solubilization ability.Tensiometric and spectrophotometric studies
2006
The self-aggregation and solubilization capability of a series of amphiphilic copolymers obtained by derivatisation of polymeric chain of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) with polyethylene glycols (PEG, being different molecular weight 2000 or 5000 Da, PEG2000 and PEG5000, respectively) and/or hexadecylamine alkyl chain (C16), namely PHEA–PEG2000, PHEA–PEG5000, PHEA–C16, PHEA–PEG2000–C16 and PHEA–PEG5000–C16, have been evidenced by performing systematic tensiometric and spectrophotometric studies. All measurements have been performed at 25.0 °C over a wide copolymer concentration range. The tensiometric results have shown that, for all copolymers studied, the surface tension…
Content of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in fish from Latvian lakes
2013
Seventeen polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) of the highest priority as well as twelve dioxin-like polychlorinated biphenyls (dl-PCBs) were analyzed in the muscle tissues of the following freshwater fish species sampled from eleven Latvian freshwater lakes: perch (Perca flavescens), carp (Cyprinus carpio), eel (Anguilla rostrata), bream (Abramis brama), chub (Leuciscus cephalus), pike (Esox lucius), sheatfish (Silurus glanis) and roach (Rutilus). To analyze the selected persistent organic pollutants in fish matrices, an optimization of EPA-1613 and EPA-1668A clean-up procedures was carried out, followed by validation of the analytical procedure …
Branched versus linear oligo(dimethylsiloxane): Differences in their thermodynamic interaction with solvents
2010
The thermodynamic behavior of linear and of branched oligo(dimethylsiloxane) (O-DMS) solutions was studied by means of vapor pressure measurements and vapor pressure osmometry at different temperatures for the thermodynamically favorable solvent THF. The branched material required for that purpose was synthesized and afterwards fractionated by means of the single solvent acetone to eliminate components of low degrees of branching. The Flory-Huggins interaction parameters, χ, for the systems THF/O-DMS as a function of composition pass a minimum at all temperatures (25, 40, and 60 °C) in the case of the branched material. For the unbranched oligomer such a minimum is only observed at 60 °C. A…
Rutile crystals as potential trace element and isotope mineral standards for microanalysis
2009
Abstract The present paper reports trace element concentrations of 15 elements (V, Cr, Fe, Zr, Nb, Mo, Sn, Sb, Hf, Ta, W, Lu, Pb, Th and U) as well as Pb and Hf isotope data for four relatively homogeneous and large (centimeter size) rutile grains. Methods employed are SIMS, EMP, LA-ICP-MS, ID-MC-ICP-MS and TIMS. For most elements homogeneity is usually within ± 10% and occasionally variations are even narrower (± 5%), particularly in the core of two of the studied grains. The trace element concentrations of the grains span a broad compositional range (e.g., Zr concentrations are ca. 4, 100, 300 and 800 ppm). Provisional concentration values, calculated based on the homogeneity of the eleme…