Search results for "USP"
showing 10 items of 1290 documents
Precise Indication of Air Pollution Sources
2002
The present paper is a report of an application of Mossbauer spectroscopy, X-ray diffractometry, thermogravimetric analysis and PIXE in the characterization of the particulate matter in atmospheric aerosols in Vitoria Metropolitan Region (VMR), Brazil. The main sources of particulate matter, natural, industrial and antropogenic (from human activities), have been studied to identify its contribution in the atmospheric particles. Through the years 1995 to 1999 samples of total suspended particles (TSP, O ⩽; 100 μm) were collected from six points within VMR and in two points the inhalable particles (PM10, O ⩽ 10 μm). In addition, a receptor modeling was used helping in a precise indication of …
A dihydrogen arsenate-mediated supramolecular network: crystal structure and magnetic properties of {[(bipy)Cu(μ-H2AsO4)(H2AsO4)]2}n
2002
Treatment of an aqueous suspension of Cu(OH)2 and 2,2′-bipyridine (bipy) with either Na2HAsO4·7H2O (1∶1∶2) or As2O5 (1∶1∶1) yields single crystals of {[(bipy)Cu(μ-H2AsO4)(H2AsO4)]2}n, 1, on standing. The solid-state structure of 1 consists of a three dimensional supramolecular network, supported by a combination of coordination covalent, hydrogen bonding and face-to-face π–π interactions. Variable temperature magnetic susceptibility measurements reveal very weak antiferromagnetic coupling between Cu(II) centres across the dihydrogen arsenate bridges (J = −0.58 cm−1).
Interactions between chemical evolution (hydration) and physical evolution (setting) in the case of tricalcium silicate
1994
This paper describes recent experimental results concerning investigation of the parameters which determine, on the one hand, the kinetics of hydration of tricalcium silicate and the thermodynamic, morphological and structural characteristics of C-S-H and, on the other hand, the evolution of the particle interactions at the origin of setting. It is shown that, in both cases, lime concentration in solution is the most important parameter. As a consequence, the chemical evolution of the system, which controls the lime concentration in solution, determines the nature of particle interactions and the physical evolution of the suspension or paste. In return, the contacts, between particles, resu…
Kinetics of nitrogen removal in a MBR nutrient removal activated sludge system
2006
The application of membrane bioreactor (MBR) technology to biological nutrient removal (BNR) activated sludge (AS) systems is limited and uncertainty exists as to the impact of the conditions induced by the membranes on the biologically mediated processes of nutrient removal. Two main conditions associated with MBRs are (1) high total suspended solids (TSS) concentrations (8–20 g/L) and (2) different selection pressures due to biomass retention not being based on settleability, compared with conventional systems with secondary settling tanks (SSTs). Recently, Ramphao et al. [1] concluded that incorporating membranes in BNR AS makes a profound difference to the design of the system. Previous…
Iron as a source of color in river waters.
2015
Organic chromophores of total organic carbon (TOC) and those of iron (Fe) contribute to the color of water, but the relative contributions of colored organic carbon (COC%) and Fe (Fe%) are poorly known. In this study, we unraveled Fe% and COC% in 6128 unfiltered water samples collected from 94 Finnish river sites of contrasting catchment properties. According to regression analysis focusing on TOC alone, on average 84% of the mean TOC consisted of COC, while 16% was non-colored or below the color-detection limit. COC and Fe were much more important sources of color than phytoplankton (chlorophyll a as a proxy) or non-algal particles (suspended solids as a proxy). When COC and Fe were consid…
No labas ticības principa izrietošie līguma blakuspienākumi
2022
Civillikuma 1.pants noteic, ka: “Tiesības izlietojamas un pienākumi pildāmi pēc labas ticības”. Desmitiem tūkstošu spriedumu, kuros ietvertas atsauces uz šo pantu liecina par tā plašo atpazīstamību, tomēr gan tiesu praksē, gan tiesību doktrīnā joprojām pastāv neskaidrības par šī panta nozīmi. Autors analizēs un sniegs argumentētas atbildes uz šādiem problēmjautājumiem: 1) vai Civillikuma 1.pants ir uzskatāms tikai par rakstītu tiesību normu, vai arī tas ir nerakstītas tiesību normas atspoguļojums; 2) vai šajā pantā aprakstītais princips ir attiecināms tikai uz civiltiesībām; 3) kāds ir šī principa saturs, kodols, vēsturiskā attīstība, un kāda ir tā izpratne citu valstu tiesībās; 4) kādi ir …
Flow properties and hydrodynamic interactions of rigid spherical microswimmers.
2017
We analyze a minimal model for a rigid spherical microswimmer and explore the consequences of its extended surface on the interplay between its self-propulsion and flow properties. The model is the first order representation of microswimmers, such as bacteria and algae, with rigid bodies and flexible propelling appendages. The flow field of such a microswimmer at finite distances significantly differs from that of a point-force (Stokeslet) dipole. For a suspension of microswimmers, we derive the grand mobility matrix that connects the motion of an individual swimmer to the active and passive forces and torques acting on all the swimmers. Our investigation of the mobility tensors reveals tha…
Light scattering - diagnostic methods for colloidal dispersions
1993
Abstract The increasing demand from the colloid research community for quick and noninvasive experimental techniques as well as the rapid progress of modern optics and electronics have led to a considerable expansion in the field of light scattering. This review introduces the basic concepts with some emphasis on novel approaches like the study of interacting particle systems, multiple scattering techniques, and non ergodic samples. Particular attention is then devoted to recent experimental progress towards more compact and rugged instruments.
Nullité de plein droit. La compensation provoquée est un paiement anormal prohibé en période suspecte
2008
International audience; (Com. 13 févr. 2007, pourvoi n° 05-13.526, arrêt n° 228 FS-P+B+R+I, Sté Alès béton c/ André ès-qual., Juris-Data, n° 2007-037368 ; D. 2007. AJ. 583, obs. A. Lienhard ; JCP 2007. I. 153, n° 6, obs. M. Cabrillac ; Gaz. Pal. 13-14 avr. 2007. 40, note Ph. Roussel Galle)
Influence of drag and turbulence modelling on CFD predictions of solid liquid suspensions in stirred vessels
2014
Abstract Suspensions of solid particles into liquids within industrial stirred tanks are frequently carried out at an impeller speed lower than the minimum required for complete suspension conditions. This choice allows power savings which usually overcome the drawback of a smaller particle-liquid interfacial area. Despite this attractive economical perspective, only limited attention has been paid so far to the modelling of the partial suspension regime. In the present work two different baffled tanks stirred by Rushton turbines were simulated by employing the Eulerian-Eulerian Multi Fluid Model (MFM) along with either the Sliding Grid algorithm (transient simulations) or the Multiple Refe…