Consequence analysis by means of characteristic curves to determine the damage to buildings from bursting spherical vessels

Since the damage suffered by buildings as a consequence of explosions usually affect the people inside them, it is important to take it into account when performing consequence analysis. The aim of this paper is to provide a methodology to estimate consequences to buildings from pressure waves produced by spherical vessel burst. This is done by combining characteristic overpressure–impulse–distance curves [González Ferradás, E., Diaz Alonso, F., Sanchez Perez, J.F., Miñana Aznar, A., Ruiz Gimeno, J. and Martinez Alonso, J., 2006, Characteristic overpressure–impulse–distance curves for vessel burst, Process Safety Progress, 25(3): 250–254] with PROBIT equations. The main advantage of this methodology is that it allows an overview of all the magnitudes involved, as damage is shown in the same graph as the overpressure, impulse and distance. In this paper diagrams and equations are presented to determine minor damage to buildings (broken windows, displacement of doors and window frames, tile displacement, etc.), major structural damage (cracks in walls, collapse of some walls) and collapse (the damage is so extensive that the building is partially or totally demolished).     

Uphill permeation of Cr(VI) using Hostarex A327 as ionophore by membrane-solvent extraction processing

The transport of chromium by the emulsion pertraction technology (EPERT) using Hostarex A327 (tertiary amine) as a carrier has been investigated. The permeation of the metal is studied as a function of various experimental variables: hydrodynamic conditions, concentration of Cr(VI) and HCl in the source phase, carrier concentration and diluent in the organic phase, strippant concentration in the stripping phase and support characteristics of the membrane. The mass transfer coefficient and the thickness of the aqueous source boundary layer were estimated from the experimental data. Furthermore, the selectivity of the Hostarex A327-bases EPERT towards different metal ions and the behaviour of the system against other carriers are presented.     

Assessment of toxicity of a glyphosate-based formulation using bacterial systems in lake water

A new Aeromonas bioassay is described to assess the potential harmful effects of the glyphosate-based herbicide, Roundup^®, in the Albufera lake, a protected area near Valencia. Viability markers as membrane integrity, culturability and β-galactosidase production of Aeromonas caviae were studied to determine the influence of the herbicide in the bacterial cells. Data from the multifactor analysis of variance test showed no significant differences (P > 0.05) between A. caviae counts of viability markers at the studied concentrations (0, 50 and 100 mg l⁻¹ of glyphosate).

The effects of Roundup^® on microbial biota present in the lake were assessed by measuring the number of indigenous mesophilic Aeromonas in presence of different amounts of the herbicide at 0, 50 and 100 mg l⁻¹ of glyphosate. In samples containing 50 and 100 mg l⁻¹ of glyphosate a significant (P < 0.05) increase in Aeromonas spp. counts and accompanying flora was observed.

The acute toxicity of Roundup^® and of Roundup^® diluted with Albufera lake water to Microtox^® luminescent bacterium (Vibrio fischeri) also was determined. The EC₅₀ values obtained were 36.4 mg l⁻¹ and 64.0 mg l⁻¹ of glyphosate respectively. The acidity (pH 4.5) of the herbicide formulation was the responsible of the observed toxicity.     

Gewebswachstum in der perinatalen Periode

The Science of Nature -     

Effect of substrate Henry's constant on biofilter performance

Butanol, ether, toluene, and hexane, which have Henry's constants ranging from 0.0005 to 53, were used to investigate the effects of substrate solubility or availability on the removal of volatile organic compounds (VOCs) in trickle-bed biofilters. Results from this study suggest that, although removal of a VOC generally increases with a decrease in its Henry's constant, an optimal Henry's constant range for biofiltration may exist. For the treatment of VOCs with high Henry's constant values, such as hexane and toluene, the transfer of VOCs between the vapor and liquid phases or between the vapor phase and the biofilm is a rate-determining step. However, oxygen (O2) transfer may become a rate-limiting step in treating VOCs with low Henry's constants, such as butanol, especially at high organic loadings. The results demonstrated that in a gas-phase aerobic biofilter, nitrate can serve both as a growth-controlling nutrient and as an electron acceptor in a biofilm for the respiration of VOCs with low Henry's constants. Microbial communities within the biofilters were examined using denaturing gradient gel electrophoresis to provide a more complete picture of the effect of O2 limitation and denitrification on biofilter performance.     

Online hourly determination of 62 VOCs in ambient air: system evaluation and comparison with another two analytical techniques

This paper presents results of the processing and validation of data collected by an automatic gas chromatograph (AGC). This system was used to monitor 62 volatile organic compounds (VOCs) in urban air in the Basque Country, Spain. The nonpolar compounds (C2-C10) identified-paraffins, olefins, aromatics, and chlorinated compounds-accounted for 88% of the mass of total non-methane hydrocarbons (TNMHCs) in ambient air. The evaluation of linearity, precision, detection limits (DLs), and stability of retention times (RTs) indicates that the equipment is suitable for measuring ambient air automatically for prolonged periods (6 months). The calibration of the equipment using response factors calculated on the basis of the effective carbon number (ECN) showed variations of over 10% for acetylene, isoprene, and n-hexane. The results provided by the automatic chromatograph correlated significantly with simultaneous results from other widely used techniques for determining VOCs in ambient air: (1) portable GC, equipped with photoionization detector (PID), and (2) active adsorption on Tenax-TA followed by thermal desorption and chromatographic analysis.     

Queen primer pheromone affects conspecific fire ant (<Emphasis Type="Italic">Solenopsis invicta</Emphasis>) aggression

Monogyne fire ant, Solenopsis invicta, colony workers are territorial and are aggressive toward members of other fire ant colonies. In contrast, polygyne colony workers are not aggressive toward non-nestmates, presumably due to broader exposure to heritable and environmentally derived nestmate recognition cues (broad template). Workers from both monogyne and polygyne fire ant colonies execute newly mated queens after mating flights. We discovered that monogyne and polygyne queens have a remarkable effect on conspecific recognition. After removal of their colony queen, monogyne worker aggression toward non-nestmate conspecifics quickly drops to merely investigative levels; however, heterospecific recognition/aggression remains high. Queenless monogyne or polygyne worker groups were also not aggressive toward newly mated queens. Queenless worker groups of both forms that adopted a monogyne-derived newly mated queen became aggressive toward non-nestmate workers and newly mated queens. We propose that the powerful effect of fire ant queens on conspecific nestmate recognition is caused by a queen-produced recognition primer pheromone that increases the sensitivity of workers to subtle quantitative differences in nestmate recognition cues. This primer pheromone prevents the adoption of newly mated queens (regulation of reproductive competition) in S. invicta and when absent allows queenless workers to adopt a new queen readily. This extraordinary discovery has broad implications regarding monogyne and polygyne colony and population dynamics.     

Speciation as a screening tool for the determination of heavy metal surface water pollution in the Guadiamar river basin

The Guadiamar river basin has traditionally received pollutants from two main sources: in its northern section of mining origin, and in its southern section (next to Do?ana National Park) from urban-industrial and agricultural sources. In April 1998, the spill of 6 million m3 of mining wastes (acidic waters and sludge) severely polluted the Guadiamar river basin with heavy metals, which caused serious damage to the local ecosystem. There is a direct association between the physicochemical speciation of an element and its toxicity, biological activity, bioavailability, solubility, etc. This work describes a distribution study of the metals Zn, Cd, Pb and Cu by speciation analysis of surface waters in eleven sampling points of the Guadiamar river basin. Four metal fractions were determined using anodic stripping voltammetry: labile metal forms, H+ exchangeable metal forms, strongly inert forms (associated with organic and inorganic matter in solution), and forms associated with suspended matter. Total concentrations in surface waters followed the trend Zn > Cu > Pb > Cd. The speciation study showed that Zn and Cd were present to a large extent in available forms (labile and H+ exchangeable), while Pb and Cu were found mostly in the less available forms (strongly inert). Moreover, the available forms were found in the northern section (mining pollution) and the strongly inert forms in the southern section (urban, industrial and agricultural pollution). These results can illustrate the potential value of speciation to discern between different sources of pollution.