Rapid Detection and Suppression of Mining Equipment Cab Fires

The National Institute for Occupational Safety and Health (NIOSH/PRL) conducted a series of large-scale experiments to evaluate the effectiveness of optical flame detectors, photoelectric smoke detectors, and combined ionization and photoelectric smoke detectors for rapidly detecting mining equipment cab fires. The detector alarm times were then used to trigger the discharge of a fire inerting system inside the cab to suppress cab material fires. This paper discusses the types of fire detectors tested, the experiments that were conducted, and the results that were obtained. Conclusions are that rapid detection of equipment cab fires can be achieved to trigger the discharge of a fire inerting system inside the cab to protect the operator in the cab.     

Nanomaterials for environmental studies: Classification, reference material issues, and strategies for physico-chemical characterisation

NanoImpactNet is a European Commission Framework Programme 7 (FP7) funded project that provides a forum for the discussion of current opinions on nanomaterials in relation to human and environmental issues. In September 2008, in Zurich, a NanoImpactNet environmental workshop focused on three key questions:

1.

What properties should be characterised for nanomaterials used in environmental and ecotoxicology studies?

2.

What reference materials should be developed for use in environmental and ecotoxicological studies?

3.

Is it possible to group different nanomaterials into categories for consideration in environmental studies?

Such questions have been, at least partially, addressed by other projects/workshops especially in relation to human health effects. Such projects provide a useful basis on which this workshop was based, but in this particular case these questions were reformulated in order to focus specifically on environmental studies. The workshop participants, through a series of discussion and reflection sessions, generated the conclusions listed below.The physicochemical characterisation information identified as important for environmental studies included measures of aggregation/agglomeration/dispersability, size, dissolution (solubility), surface area, surface charge, surface chemistry/composition, with the assumption that chemical composition would already be known.There is a need to have test materials for ecotoxicology, and several substances are potentially useful, including TiO₂ nanoparticles, polystyrene beads labelled with fluorescent dyes, and silver nanoparticles. Some of these test materials could then be developed into certified reference materials over time.No clear consensus was reached regarding the classification of nanomaterials into categories to aid environmental studies, except that a chemistry-based classification system was a reasonable starting point, with some modifications. It was suggested, that additional work may be required to derive criteria that can be used to generate such categories, that would also include aspects of the material structure and physical behaviour.     

Organochlorine pesticides in colostrums in case of normal and preterm labor (IASI, Romania)

Assessment of organochlorine pesticides (OCPs) in human body is important for human health because they have weak estrogenic or antiestrogenic effects and are considered endocrine disrupters. We used colostrum of women as indicator for levels of OCPs in human body for mothers with normal and preterm labor from eastern part of Romania. Sixty- three samples of colostrum were extracted by solid-phase extraction. Analyses were carried out using gas chromatography coupled to mass spectrometry (GC-MS). OCPs have been detected in all samples, with p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) and γ-hexachlorocyclohexane (γ-HCH) being at the highest concentrations. Of the organochlorines measured in clostrum samples from women in preterm labor, median levels of DDTs (470 ng/g) and HCHs (99 ng/g) were higher than for the same compounds from women in normal labor (median of DDTs = 268 ng/g and median of HCHs = 96 ng/g). Normal labor had higher median concentrations of HCB (19.5 ng/g) versus preterm labor (14 ng/g). Statistical data show high Spearman correlation coefficients between various OCPs. We found a good correlation between α-, γ-, β- and δ- HCH isomers (p < 0.001) for both normal and preterm labor. The most abundant target compound was p,p’-DDE (median value 96 ng/g, and 137 ng/g for mother with normal and preterm labor, respectively) in all colostrum samples. The estimated daily intakes of HCHs by infants exceeded corresponding Health Canada guidelines.     

Does remediation save lives? — On the cost of cleaning up arsenic-contaminated sites in Sweden

Sweden has only just begun remediation of its many contaminated sites, a process that will cost an estimated SEK 60,000 million (USD 9100 million). Although the risk assessment method, carried out by the Swedish EPA, is driven by health effects, it does not consider actual exposure. Instead, the sites are assessed based on divergence from guideline values. This paper uses an environmental medicine approach that takes exposure into account to analyse how cancer risks on and near arsenic-contaminated sites are implicitly valued in the remediation process. The results show that the level of ambition is high. At 23 contaminated sites, the cost per life saved varies from SEK 287 million to SEK 1,835,000 million, despite conservative calculations that in fact probably underestimate the costs. It is concluded that if environmental health risks are to be reduced, there are probably other areas where economic resources can be used more cost-effectively.     

Incorporating amylopectin in poly(lactic acid) by melt blending using poly(ethylene‐co‐vinyl alcohol) as a thermoplastic carrier. (I) morphological characterization

In this study, the possibility of using a biodegradable grade of thermoplastic poly(ethylene‐co‐vinyl alcohol) with high (71 mol %) vinyl alcohol (EVOH‐29), as a carrier to incorporate the renewable and biodegradable component amylopectin (AP) into poly(lactic acid) (PLA) through melt blending, was investigated. The effect of using a plasticizer/compatibilizer (glycerol) in the blend systems was also investigated. In a first step, the EVOH/AP blends were produced and thereafter, in a second step, these were mixed with PLA. In this first study, the blend morphology was investigated using optical microscopy, scanning electron microscopy and Raman imaging spectroscopy and the thermal properties were measured by differential scanning calorimetry. Despite the fact that EVOH and AP are both highly polar, their blends were immiscible. Still, the blends exhibited an excellent phase dispersion on a micron level, which was enhanced further by the addition of glycerol. A good phase dispersion was finally observed by incorporation of the latter blends in the PLA matrix, suggesting that the proposed blending route can be successfully applied for these systems. Finally, the Differential scanning calorimetry (DSC) data showed that the melting point of EVOH dropped in the EVOH/AP blends, but the properties of the PLA phase was still relatively unaffected as a result of blending with the above components. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Development of a new procedure for precise determination of viral aerosol lethal dose (ALD50) for birds

This paper describes a new method for precise determination of viral aerosol lethal dose (ALD₅₀) and reports the results obtained for birds exposed by H5N1 Avian influenza A strain under controlled laboratory conditions. The reported method utilizes our recently developed personal bioaerosol sampler capable of monitoring viable virus concentration in the ambient air. Up to six laboratory animals could be located in a specially designed aerosol chamber and exposed in parallel by an airborne strain of interest to generate the amount of data sufficient for representative statistical analysis. A concentration of viable airborne virus was measured by the personal aerosol samplers directly in the breathing zone of each particular bird. The results show a very low inter-sampler variation used for each particular run, which was confirmed by a single factor ANOVA test undertaken for all six personal samplers involved in each experiment. As was shown, the difference in amount of viruses collected by all samplers during each particular run was not statistically significant. It was found that the ALD₅₀ for approximately 400-g birds exposed to H5N1 Avian influenza A strain A/Chicken/Suzdalka/Nov-11/2005 was around 26.5 FFU (focus forming units).     

Effect of primary amine hydrocarbon chain length for the selective catalytic reduction of NOx from diesel engine exhaust

The effect of increasing primary amine hydrocarbon chain length on the SCR of NO_x from diesel engine exhaust was investigated and compared to ammonia. Methylamine (CH₃NH₂), ethylamine (CH₃CH₂NH₂), propylamine (CH₃CH₂CH₂NH₂) and butylamine (CH₃CH₂CH₂CH₂NH₂) were tested using a 12 cell mini core NH₃ - SCR catalyst cut from a 400 cpsi block. There is a steady decrease in NO_x conversion as the length of the hydrocarbon chain increases (from 50% for methylamine to 26% for butylamine). For the same number of carbons in the amine, primary amines are more active reductants than methyl substituted secondary or tertiary amines. For example, ethylamine (NO_x conversion of 45%) is more active than dimethylamine (NO_x conversion of 34%).Since the amines are reactive in the gas phase in the temperature range of diesel engine exhaust, gas phase conversions were estimated by replacing the mini core SCR catalyst with an equivalent length of quartz beads. There was no smooth transition in gas phase NO and NO_x conversions with increasing hydrocarbon chain length. The results suggest a different mechanism for gas phase reactions depending on the nature of the amine.     

Influence of Al2O3 on the performance of CeO2 used as catalyst in the direct carboxylation of methanol to dimethylcarbonate and the elucidation of the reaction mechanism

In this paper we show that modification of ceria by loading alumina strongly reduces the oxidation of methanol and the consequent reduction of Ce(IV) to Ce(III) with increase of both the life of the catalysts and their selectivity. The combination of surface techniques (XPS and BET) with structural techniques (XRD) has allowed a good characterisation of the working catalysts. Spectroscopic analyses (DRIFT and multinuclear solid state and solution NMR) have permitted the monitoring of the species formed on the surface of the catalyst and released from it. The formation of DMC takes place in successive steps such as (i) interaction of methanol with the catalyst surface with the formation of the surface-bound OCH₃; (ii) building on the catalyst surface of the hemicarbonate moiety [–OCH₃ → –OC(O)OCH₃]; and (iii) reaction of the latter with the gas-phase methanol to afford the organic carbonate.     

Viscoelastic properties of latex paint films in tension: Influence of the inorganic phase and surfactants

The tensile properties of latex coatings were investigated with a set of custom formulated artist-type paints at an age of 1 year. All films in the study contained a poly(methyl methacrylate-cobutyl acrylate) binder exhibiting a glass-transition at approximately 10 °C. The viscoelastic behaviour of the latex matrix is first highlighted through a series of experiments involving different strain histories and temperatures. Influence of the inorganic particle concentration and geometry is then illustrated using TiO₂ and calcined kaolin for the secondary phase. Experimental data from a wide range of conditions are summarised through master curves of secant modulus and failure strains using time–temperature superposition. The results indicate that the latex films behave in a rheologically simple manner and it is possible to predict the response outside of the experimental time-scale. An analysis by similar methods is also given for TiO₂ pigmented films with/without surfactant removed by immersion in water. Differential scanning calorimetry and atomic force microscopy were also used in conjunction with mechanical tests. The combined findings suggest that a fraction of surfactant migrates to the TiO₂ interface during film formation, where it interferes with adhesion of the acrylic matrix.