Recycled water: potential health risks from volatile organic compounds and use of 1,4-dichlorobenzene as treatment performance indicator

Characterisation of the concentrations and potential health risks of chemicals in recycled water is important if this source of water is to be safely used to supplement drinking water sources. This research was conducted to: (i) determine the concentration of volatile organic compounds (VOCs) in secondary treated effluent (STE) and, post-reverse osmosis (RO) treatment and to; (ii) assess the health risk associated with VOCs for indirect potable reuse (IPR). Samples were examined pre and post-RO in one full-scale and one pilot plant in Perth, Western Australia. Risk quotients (RQ) were estimated by expressing the maximum and median concentration as a function of the health value. Of 61 VOCs analysed over a period of three years, twenty one (21) were detected in STE, with 1,4-dichlorobenzene (94%); tetrachloroethene (88%); carbon disulfide (81%) and; chloromethane (58%) most commonly detected. Median concentrations for these compounds in STE ranged from 0.81 μg/L for 1,4-dichlorobenzene to 0.02 μg/L for carbon disulphide. After RO, twenty six (26) VOCs were detected, of which 1,4-dichlorobenzene (89%); acrylonitrile (83%) chloromethane (63%) and carbon disulfide (40%) were the more frequently detected. RQ(max) were all below health values in the STE and after RO. Median removal efficiency for RO was variable, ranging from −77% (dichlorodifluoromethane) to 91.2% (tetrachloroethene). The results indicate that despite the detection of VOCs in STE and after RO, their human health impact in IPR is negligible due to the low concentrations detected. The results indicate that 1,4-dichlorobenzene is a potential treatment chemical indicator for assessment of VOCs in IPR using RO treatment.     

J-OFFICE办公空间,上海,中国

J-Office办公空间位于由原第五化纤厂厂区改造的五维创意产业园区中,整个项目由一栋三跨建于1960年代的老厂房改造而成。包围整个办公区的绸墙和位于办公区后院的茶室是建筑师对于"低技参数化"建造方式的实践,并且也成为了实际项目操作前的试验性建造。在整个三跨厂房的空间规划中,三跨厂房与原     

Dried plum products as a substitute for phosphate in chicken marinade

In order to address the growing demand for more natural poultry products, alkaline phosphates commonly used in chicken breast meat marinades were replaced with plum ingredients and evaluated. For initial sensory evaluation, 200 consumers of chicken were served a small portion of the chicken breast on a plate and were asked to evaluate the product for overall impression, flavor, and texture on a 9-point hedonic scale with 1 = "dislike extremely" and 9 = "like extremely." Also, a 5-point just-about-right (JAR) scale was used on questions about tenderness, juiciness, overall flavor, and saltiness. Both hedonic and JAR demonstrated that the marinades of plum concentrate and the blend of plum fiber and powder were not distinguishable from the control (P > 0.05). Using two different percentages of fiber/powder blend, two different percentages of concentrate, sodium tripolyphosphate (STPP), and no marinade, measurements were made for marinade per cent pickup, thaw loss, and cook loss. Plum concentrate at 1.1% was most similar to STPP in marinade per cent pickup, thaw loss, drip loss, and cook loss. These results show that plum ingredients can potentially be used as a substitute in standard phosphate marinades. PRACTICAL APPLICATION: Consumers are increasingly demanding more natural foods with less artificial additives. This research presents the results of experiments using dried plum ingredients as a substitute for phosphates commonly used in marinades for chicken. Results indicate that dried plum ingredients may be a suitable substitute for phosphates in marinades.     

Fast 3D thermal simulation of power module packaging

This paper presents a thermal model that uses a Fourier series solution to the heat equation to carry out transient 3D thermal simulation of power device packaging. The development and implementation of this physics‐based method is described. The method is demonstrated on a stacked 3D multichip module. The required aspects of 3D heat conduction are captured successfully by the model. Compared with previous thermal models presented in literature, it is fast, accurate and can be easily integrated with an inverter circuit simulator to model realistic converter load cycles. Copyright © 2012 John Wiley & Sons, Ltd.     

Thermodynamics of noncovalent interactions in hydrophobically‐substituted water‐soluble polymers from intrinsic viscosity measurements: Application to nucleobase‐substituted pullulans

Hydrophobically substituted water‐soluble polymers (HSWSP) act as associative thickeners through the reversible crosslinking from noncovalent interactions between the various groups on the polymer chains in aqueous solution. This article shows how the intrinsic viscosity (IV) of nonionic HSWSP can be used to define the thermodynamics of these interactions. Literature data on the IV of pullulans substituted by nucleobase ester groups (thyminylbutyryl and adeninylbutyryl) (Mocanu et al., Can J Chem, 1995, 73, 1933) are used as an exemplar of these procedures. The intramolecular crosslinking in these substituted pullulans is deduced to be “unimolecular” (association constant K₁ = 1 M^?1), as contrasted with the “bimolecular” behavior expected from the stacking of the free nucleobases; evidently the crosslinking results from hydrophobic interactions between the butyryl linking groups and the main chain. The results are compared with those from other HSWSP, and from cosolute binding systems. The use of the water–octanol partition coefficients of model systems to elucidate hydrophobic interactions in HSWSP, and of denaturant cosolutes (especially urea) to diagnose the presence and strength of these interactions, are also discussed. Emphasis is placed on the need for further such studies to identify the interactions underlying the rheological behavior of the nonionic HSWSP, and of the more common ionic types. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Microwave dielectric properties of flexible butyl rubber–strontium cerium titanate composites

Butyl rubber–strontium cerium titanate (BS) composites have been prepared by hot pressing. The tensile tests show that the BS composites are flexible. The dielectric properties of the composites have been investigated at 1 MHz and 5 GHz as a function of ceramic contents. The composite with volume fraction 0.43 of ceramic filler has a dielectric constant (ε_r) of 11.9 and dielectric loss (tan δ) 1.8 × 10^?3 at 5 GHz. The measured values of ε_r are compared with the effective values calculated using different theoretical models. The thermal conductivity of the composites is found to increase with ceramic contents and reaches a value of 4.5 Wm^?1 K^?1 for maximum filler loading 0.43 volume fraction. The coefficient of thermal expansion of the composites decreases gradually with filler loading and reaches a minimum value of 30.2 ppm °C^?1 at a volume fraction 0.43. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The Role of Aluminum in the Detonation and Post‐Detonation Expansion of Selected Cast HMX‐Based Explosives

In order to improve understanding of how aluminum contributes in non‐ideal explosive mixtures, cast‐cured formulations have been analyzed in a series of cylinder tests and plate‐pushing experiments. This study describes the contribution of 15 % aluminum (median size of 3.2 μm) vs. lithium fluoride (an inert substitute for aluminum; <5 μm) in cast‐cured HMX formulations in different temporal regimes. Small cylinder tests were performed to analyze the detonation and wall velocities (1–20 μs) for these formulations. Near‐field blast effects of 58 mm diameter spherical charges were measured at 152 mm and 254 mm using steel plate acceleration. Pressure measurements at 1.52 m gave information about free‐field pressure at several milliseconds. While the observed detonation velocities for all formulations were within uncertainty, significantly higher cylinder wall velocities, plate velocities, and pressures were observed for the aluminum formulations at ≥2 μs. Additionally, hydrocode calculations were performed to determine how non‐ideal behavior affected the plate test results. Collectively, this work gives a clearer picture of how aluminum contributes to detonation on timescales from 1 μs to about 2 ms, and how the post‐detonation energy release contributes to wall velocities and blast effects. The experiments indicate that significant aluminum reactions occur after the CJ plane, and continue to contribute to expansion at late times.     

Investigating the Mechanical Properties of RDX Crystals Using Nano‐Indentation

The shock sensitivity of RDX is of major interest for the development of insensitive munitions. Previous research has implied that internal defects that form within RDX crystals have a strong sensitising effect, increasing the probability of shock initiation. During the NATO Reduced sensitivity RDX Round Robin (R⁴) program the number of internal defects within RDX crystals of differing qualities were assessed by optical microscopy and a scoring system. The results suggested that RDX crystals with many internal defects were more sensitive. Studies investigating the mechanical properties of bulk RDX have shown that lots consisting of poorer crystals are weaker. This study investigates the mechanical properties of individual crystals from different RDX lots using nano‐indentation. It is shown that crystals with many internal defects have reduced modulus of elasticity, stiffness and prone to greater deformation under applied load. The results also show a correlation between these parameters and previously reported shock sensitivity data.     

Analysis and Optimization of a Synthetic Milkweed Floral Attractant for Mosquitoes

A pentane extract of flowers of common milkweed, Asclepias syriaca (Asclepiadaceae), elicited significant orientation from both male and female Culex pipiens in a dual-port flight olfactometer. Analysis of the extract by gas chromatography-mass spectrometry revealed six major constituents in order of relative abundance: benzaldehyde, (E)-β-ocimene, phenylacetaldehyde, benzyl alcohol, nonanal, and (E)-2-nonenal. Although not all were collected from the headspace profile of live flowers, a synthetic blend of these six compounds, when presented to mosquitoes in the same levels and proportions that occur in the extract, elicited a response comparable to the extract. Subtractive behavioral bioassays demonstrated that a three-component blend consisting of benzaldehyde, phenylacetaldehyde, and (E)-2-nonenal was as attractive as the full blend. These findings suggest the potential use of synthetic floral-odor blends for monitoring or control of both male and female disease-vectoring mosquitoes.