Numerical investigation for pressure mitigation effects of dike on blast wave

The three-dimensional and two-dimensional axisymmetric fluid dynamics simulations were carried out to clarify the blast pressure mitigating effects of dike’s configuration in hemispherical explosion. The simulated peak overpressure on the ground under the hemispherical explosion was compared with the empirical formula by Kingery, and the simulated data were validated. In the analysis, the simplification techniques for the numerical simulation were employed under the following two assumptions. The pressure distribution behind the wide dike was estimated using the axisymmetric flowfield, and the back step model was applied under the small condition for θ, the angle formed by the ground and the line between the explosion core and the dike front corner. From the simulated results, it is clarified that the large θ provided the great reduction of the blast wave pressure at faraway position. In the small θ condition, the conditions of the dike end position and the dike height were significant parameters determining the magnitude of pressure reduction and mitigated area. The pressure reduction at the dike end and mitigated area were predicted numerically, and related to the dike conditions.     

Maternal-fetal distribution and transfer of dioxins in pregnant women in Japan, and attempts to reduce maternal transfer with Chlorella (Chlorella pyrenoidosa) supplements

Dioxins can be transferred from mother to fetus via the placenta, or to nursing infants via breast milk, potentially causing developmental health problems in children. To assess pediatric health risks from dioxins, exposure of mothers and children to dioxins must be clarified. Methods of reducing maternal transfer of dioxins should also be investigated. Concentrations of 28 dioxin (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and co-planar polychlorinated biphenyls) congeners in blood, adipose tissue, breast milk, cord blood and placenta collected from 44 pregnant Japanese women were measured. In addition, to investigate potential reductions in maternal transfer of dioxins, 23 pregnant women were instructed to take Chlorella pyrenoidosa supplements during pregnancy. Correlations were observed between dioxin total toxic equivalents (total TEQ) in blood and total TEQ in adipose tissue (r=0.913, P<0.0001), breast milk (r=0.695, P=0.0007), and cord blood (r=0.759, P<0.0001). Dioxin levels transferred to fetuses and nursing infants reflect cumulative maternal concentrations of dioxins. A linear regression equation was introduced to predict total TEQ in breast milk and cord blood from dioxin levels in maternal blood, which should prove useful in evaluating fetal and infant risk of dioxin exposure. Total TEQ in cord blood were approximately 26% lower than in maternal blood (P<0.0001). The results of this study suggest that transplacental transfer differs depending on the dioxin congener. Total TEQ in breast milk were approximately 30% lower in the Chlorella group than in controls (P=0.0113). This finding suggests that maternal transfer of dioxins can be reduced using dietary measures such as Chlorella supplements.     

Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na(2)SO(4)+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al(2)O(3) content of the fly ash. The diffusion of SO(4)(2-), Na+ and Cl- ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.     

Effect of Chlorella pyrenoidosa on fecal excretion and liver accumulation of polychlorinated dibenzo-p-dioxin in mice

The effect of Chlorella pyrenoidosa on fecal excretion and liver accumulation of polychlorinated dibenzo-p-dioxin in C57BL/6N mice administered dioxin was examined. Mice were administered 2.2 microg of 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (H6CDD) dissolved in corn oil once after a period of acclimatization, after which they were fed either a basal diet, a 10% C. pyrenoidosa diet, or a 10% Spinach diet, for five weeks. Among mice fed the 10% C. pyrenoidosa diet, cumulative fecal excretion of H6CDD over the first week following administration was significantly greater (9.2-fold) than that observed among mice fed the basal diet. Moreover, excretion during the fifth week following administration of H6CDD was still significantly greater (3.1-fold) among mice fed the 10% C. pyrenoidosa diet than among mice fed the basal diet. Five weeks after administration of H6CDD, liver accumulation of H6CDD in mice fed the 10% C. pyrenoidosa diet was significantly less than that observed among mice fed either the basal diet and the Spinach diet (by 27.9% and 34.8%, respectively). These findings suggest that C. pyrenoidosa may be useful in inhibiting the absorption of dioxins via food and the reabsorption of dioxins stored already in the body in the intestinal tract, thus preventing accumulation of dioxins within the body.     

Prevalence of Human Parainfluenza Viruses and Noroviruses Genomes on Office Fomites

The aim of this study was to evaluate the potential role of office fomites in respiratory (human parainfluenza virus 1—HPIV1, human parainfluenza virus 3—HPIV3) and enteric (norovirus GI—NoV GI, norovirus GII—NoV GII) viruses transmission by assessing the occurrence of these viruses on surfaces in office buildings. Between 2016 and 2017, a total of 130 surfaces from open-space and non-open-space rooms in office buildings located in one city were evaluated for HPIV1, HPIV3, NoV GI, and NoV GII viral RNA presence. Detection of viruses was performed by RT-qPCR method. Study revealed 27 positive samples, among them 59.3% were HPIV3-positive, 25.9% HPIV1-positive, and 14.8% NoV GII-positive. All tested surfaces were NoV GI-negative. Statistical analysis of obtained data showed that the surfaces of office equipment including computer keyboards and mice, telephones, and desktops were significantly more contaminated with respiratory viruses than the surfaces of building equipment elements such as door handles, light switches, or ventilation tracts (χ ² p = 0.006; Fisher’s Exact p = 0.004). All examined surfaces were significantly more contaminated with HPIVs than NoVs (χ ² p = 0.002; Fisher’s Exact p = 0.003). Office fomites in open-space rooms were more often contaminated with HPIVs than with NoVs (χ ² p = 0.016; Fisher’s Exact p = 0.013). The highest average concentration of HPIVs RNA copies was observed on telephones (1.66 × 10² copies/100 cm²), while NoVs on the light switches (1.40 × 10² copies/100 cm²). However, the Kruskal–Wallis test did not show statistically significant differences in concentration levels of viral RNA copies on surfaces between the all tested samples. This study unequivocally showed that individuals in office environment may have contact with both respiratory and enteric viral particles present on frequently touched surfaces.     

Waste prevention for sustainable resource and waste management

Although the 2Rs (reduce and reuse) are considered high-priority approaches, there has not been enough quantitative research on effective 2R management. The purpose of this paper is to provide information obtained through the International Workshop in Kyoto, Japan, on 11–13 November 2015, which included invited experts and researchers in several countries who were in charge of 3R policies, and an additional review of 245 previous studies. It was found that, regarding policy development, the decoupling between environmental pressures and economy growth was recognized as an essential step towards a sustainable society. 3R and resource management policies, including waste prevention, will play a crucial role. Approaches using material/substance flow analyses have become sophisticated enough to describe the fate of resources and/or hazardous substances based on human activity and the environment, including the final sink. Life-cycle assessment has also been developed to evaluate waste prevention activities. Regarding target products for waste prevention, food loss is one of the waste fractions with the highest priority because its countermeasures have significant upstream and downstream effects. Persistent organic pollutants and hazardous compounds should also be taken into account in the situation where recycling activities are globally widespread for the promotion of a material-cycling society.