Search results for "element"

Biological nutrient removal in membrane bioreactors: denitrification and phosphorus removal kinetics.

2007

The impact of including membranes for solid liquid separation on the kinetics of nitrogen and phosphorus removal was investigated. To achieve this, a membrane bioreactor (MBR) biological nutrient removal (BNR) activated sludge system was operated. From batch tests on mixed liquor drawn from the MBR BNR system, denitrification and phosphorus removal rates were delineated. Additionally the influence of the high total suspended solids concentrations present in the MBR BNR system and of the limitation of substrate concentrations on the kinetics was investigated. Moreover the ability of activated sludge in this kind of system to denitrify under anoxic conditions with simultaneous phosphate uptak…

Health effects of mercury ingested through consumption of seafood

1995

It is known world-wide literature that seafood consumption is the main source of mercury intake in people not occupationally exposed. Several studies on the presence of mercury in sea water, sediment and fish and its effects on human health have been carried out in many countries in the Mediterranean area such as Greece, Italy and Jugoslavia. Few data have been published on Sicilian coastal population, consumers of high amounts of fish and on seawater status as the starting point of alimentary chains involving marine food. This study was carried out in July 1991 and July 1992 to determine total mercury and methylmercury levels in selected populations of the coast of Sicily: fishermen in a l…

Ionic currents ofdrosophila embryonic neurons derived from selectively cultured CNS midline precursors

2000

In order to investigate the electrogenesis of defined cell populations, we applied an in vitro system that allows the selective culturing of individual Drosophila CNS precursors under different conditions. CNS midline (ML) precursors prepared from gastrula stage embryos gave rise to progeny cells with neuronal and glial morphology that expressed specific markers. Using whole-cell patch-clamp recordings, a detailed description of ionic currents present in this defined cell population is provided. Most ionic currents of cultured ML neurons were similar to other cultured Drosophila neurons, even though their embryonic origin is different. They displayed at least two voltage-gated potassium cur…

Brachionus plicatilis tolerance to low oxygen concentrations

1989

Tolerance to low oxygen concentrations is expected in Brachionus plicatilis, a rotifer adapted to live in saline warm waters. The population dynamics of a clone of this species, isolated from an endorreic saline lake, was studied under controlled laboratory conditions. Although their growth and metabolism is extremely reduced, B. plicatilis populations are able to maintain relatively high-density populations (a mean of 35 ind ml−1) in oxygen concentrations below 1 mgl−1, for more than one month. Major features of population growth related to oxygen are discussed.

ChemInform Abstract: Theoretical and Spectroscopic Studies on Imino-Carbon Palladated Pyridine-2-carbaldimines.

1987

Abstract Ab initio LCAO-MO-SCF calculations on the model compounds C 5 H 4 N-2-C(R 1 )=NH [R 1 = H ( 2c ) and R 1 = trans -PdCl(PH 3 ) 2 ( 4c )] indicate that the E - trans conformation is favored over the E - cis one by 16.9 kJ mol −1 for 2c and by 25.0 kJ mol −1 for 4c . One of the factors which stabilizes the E-trans arrangement for 4c is a weak bonding interaction between the palladium center and the pyridine nitrogen. On going from 2c to 4c a slight charge enrichment on the pyridine carbons and a more pronounced one on the nitrogen atoms is computed, whereas the charge density of the imino carbon atom is decreased. In 4c no π contribution to the PdC bond is observed. Protonation of th…

Cobalt content of foods and diets in a Spanish population

1986

The WHO Expert Committee on Food Contaminants has pointed out the need of determining the content of foods in trace elements in order to ascertain their contribution to the total intake of oligoelements through the diet. Since the contents in trace elements depend on the environmental features, it is necessary to carry out systematic determinations of trace elements in foods of local origin in order to know the exposure level of population. This work intends to study the cobalt contribution through the diet. The element intake is calculated from the cobalt content in raw foods after elimination of the non-eatable moiety by flame atomic absorption spectroscopy, after formation of a chelate w…

“Serpentone Reload” an Experience of Citizens Involvement in Regeneration of Peripheral Urban Spaces

2015

Suburbs are often very contradictory places. Despite great part of urban population live there, these parts of cities are mostly considered as degradation places. The topic of suburbs regeneration is relevant today. Nevertheless, often expensive interventions implemented by local authorities fail to regenerate their public spaces. This paper presents the experience of “Serpentone reload”, a workshop based on participatory reactivation of abandoned or underused spaces and buildings in “Cocuzzo/Serpentone” neighbourhood in Potenza (Basilicata, Italy). The workshop particularly focused on the reuse of the “Ship”, an underground building, completed in 2010, never used, because it has been perce…

Production of monodisperse uranium oxide particles and their characterization by scanning electron microscopy and secondary ion mass spectrometry

2000

Abstract Secondary ion mass spectrometry (SIMS) can be confidently used to measure uranium isotopic ratios in single particles. Dense particles of known isotopic composition and size allow the precision and the accuracy of the applied procedure to be estimated. These particles can be obtained by dissolving standard reference uranium materials, nebulizing the solution in droplets of proper diameter and collecting the particles after the desolvation and calcination of the droplets. A new instrumental set up, based on a commercial vibrating orifice aerosol generator to generate monodisperse droplets of the solutions from four uranium oxide reference materials, is described. The droplets were d…

Działania arytmetyczne w początkowej edukacji matematycznej - kształtowanie pojęć czy rozwijanie nawyków rachunkowych?

2014

Fibre break failure processes in unidirectional composites: evaluation of critical damage states

2016

Earlier work which successfully modelled the kinetics of fibre breakage in unidirectional composites under monotonic tensile loading has been extended to quantify the kinetics of fibre failure during both monotonic and sustained tensile loading. In both cases, failure was seen to occur when a critical density of large clusters (more than 16 fibres are broken within the representative volume element) of fibre breaks developed. However, in monotonic loading failure occurred very quickly after the first development of these large clusters, whereas under sustained loading the composite could accommodate greater levels of large clusters because of the lower applied load. This article is part of …