Time allocation and recycling activities

Recycling is time consuming and the time available for housework may determine the intensity of recycling activities. In this study, we conducted a survey of 546 Japanese households and asked them their daily practice of five varieties of recycling activities: (1) choice of refill products, (2) use of own shopping bags, (3) sorting of recycled papers from burnable waste, (4) use of own drinking bottles when going out, and (5) use of recycle boxes prepared at the grocery store. We also asked households to record their behavior for two successive days. By combining recycling activity data and diary data, we estimate a multivariate probit model to empirically examine whether time available for housework determines the intensity of five varieties of recycling activities. The empirical result demonstrates that an individual that can allocate sufficient time for housework tends to purchase refill products. He or she also tends to bring their own shopping bags for grocery shopping. We also find that the size of house and the number of family members determine the likelihood of recycling. A housewife living with many family members in a large house is more likely to engage in time-consuming recycling activities.     

Estimation of critical ratio of bentonite addition to tuff sand

A design method was proposed to determine the critical ratio of bentonite addition, based on a macro void ratio that considers the swelling property of bentonite. The critical ratio of bentonite addition was defined as the ratio corresponding to a macro void ratio of zero. However, when lightweight soil such as tuff sand is mixed with bentonite, the estimated critical ratio of bentonite addition is too high. Several tests on the water absorbing property of tuff sand and its permeability were conducted to confirm the concept of a revised macro void ratio. The revised macro void ratio, which takes into account the swelling of bentonite and the particle pores of lightweight soil, is much smaller than the former macro void ratio for a given ratio of bentonite addition. The estimated critical ratio of bentonite addition to tuff sand that gives a revised macro void ratio of zero is around 18% and is in good agreement with the ratio of bentonite addition beyond which the value of hydraulic conductivity does not decrease markedly.     

Polychlorinated biphenyl (118) activates osteoclasts and induces bone resorption in goldfish

To analyze the effect of polychlorinated biphenyl (PCB) 118 on fish bone metabolism, we examined osteoclastic and osteoblastic activities, as well as plasma calcium levels, in the scales of PCB (118)-injected goldfish. In addition, effect of PCB (118) on osteoclasts and osteoblasts was investigated in vitro. Immature goldfish, in which the endogenous effects of sex steroids are negligible, were used. PCB (118) was solubilized in dimethyl sulfoxide at a concentration of 10 ppm. At 1 and 2 days after PCB (118) injection (100 ng/g body weight), both osteoclastic and osteoblastic activities, and plasma calcium levels were measured. In an in vitro study, then, both osteoclastic and osteoblastic activities as well as each marker mRNA expression were examined. At 2 days, scale osteoclastic activity in PCB (118)-injected goldfish increased significantly, while osteoblastic activity did not change significantly. Corresponding to osteoclastic activity, plasma calcium levels increased significantly at 2 days after PCB (118) administration. Osteoclastic activation also occurred in the marker enzyme activities and mRNA expressions in vitro. Thus, we conclude that PCB (118) disrupts bone metabolism in goldfish both in vivo and in vitro experiments.     

Aromatization of waste polyolefin pyrolysate over H-ZSM-5 zeolite-supported gallium oxide catalysts

H-ZSM-5 zeolite-supported gallium oxides were studied as aromatization catalysts for polyolefin pyrolysate. The catalysts were prepared by a conventional physical mixing method with a gallium content of 1.0 and 4.5 wt% and were reduced in flowing hydrogen at 585°C. To test their activity, a polyolefin sample was pyrolyzed and passed over a heated catalyst layer; the product was analyzed by gas chromatography/mass spectrometry. A continuous-flow fixed-bed reactor was used for aromatization of a model gas of polyolefin pyrolysate. For chlorine-free sources at 450°C, the catalyst with only 1.0 wt% gallium exhibited activity comparable to a gallium silicate catalyst. For chlorine-contaminated sources, the catalyst with 4.5 wt% gallium sustained catalytic activity for long periods. From the activity test results, it was found that zeolite-supported gallium catalysts prepared by the physical mixing method are suitable for converting polyolefin into aromatic hydrocarbons.     

Characteristics of dioxin emissions at startup and shutdown of MSW incinerators

Dioxin concentrations from municipal waste incinerators in Japan and elsewhere often show low concentrations that comply with legal limits (in this paper, the term "dioxin" designates WHO-TEQ: PCDD/Fs+dioxin-like PCB). However, such data is usually generated under normal steady state operational conditions, and there has been little investigation of releases occurring during startup and shutdown. It is important, therefore, to ascertain quantitatively emissions in an unsteady state (startup and shutdown) in order to correctly evaluate the relationship between emissions from a facility and the surrounding environment. The present study aimed to examine dioxin emissions of a continuously operated incinerator at startup and shutdown, and estimating the time period of greatest emission, and the processes causing dioxin generation. The startup process was divided into five stages and the shutdown into two; at each stage, dioxins in the flue gas were measured at the boiler outlet and the stack. From the concentration of dioxins and the flue gas volume at each stage, the amount of dioxins at startup and shutdown were calculated, and these were compared with that under steady state conditions. Dioxin concentration at the stack under steady state conditions was a very low level, while those at startup and shutdown were higher. In the case where dioxin concentration under a steady state is a low level like in this study, it is indicated that the total annual dioxin emission from a facility could be attributed to the startup periods.     

Efficient depolymerization and chemical conversion of polyamide 66 to 1,6-hexanediol

Journal of Material Cycles and Waste Management - Polyamide 66 was efficiently depolymerized and chemically converted by treatment with supercritical MeOH in the presence of glycolic acid. The...     

Degradation of monofluorophenols in water irradiated with gaseous plasma

Decomposition of aqueous monofluorophenols (MFPs) was investigated by contact glow discharge electrolysis (CGDE). During CGDE, both MFPs and the corresponding total organic carbon (TOC) in water were consumed smoothly, suggesting that carbon atoms of benzene nucleus could be eventually mineralized to inorganic carbon (IC). And all the fluorine atoms in the MFPs were equally converted to fluoride ions. Based on the primary intermediates from each starting materials, it showed that aromatic hydroxylation preferentially occurred at the para-or ortho-position to the phenolic OH group of each MFPs. The disappearance of both MFPs and TOC followed the first-order rate law. The apparent rate constants for the decay of MFPs were independent from the pK_a values of MFPs.     

Urban climate in the Tokyo metropolitan area in Japan

Long-term climate changes related with urbanization in Tokyo, Japan, and recent temperature and heavy rainfall distribution in the Tokyo metropolitan area are reviewed. A relatively high temperature increase in annual mean temperature at the rate of 3.0°C/century was detected in Tokyo for the period 1901–2015. Some observational evidence showed the existence of both thermal and mechanical effects of urbanization on recent heavy rainfall occurrences, and modeling studies also support precipitation enhancement. Urban influences were recognized in other climatological elements, such as number of fog days, relative humidity, and wind circulation.     

Exhaustive breakdown of aqueous monochlorophenols by contact glow discharge electrolysis

The aqueous monochlorophenols were degraded by contact glow discharge electrolysis (CGDE), in which plasma was generated in a localized zone between an electrolytic solution and an anode. With the decay of monochlorophenols, the amount of total organic carbon (TOC) also decreased smoothly, indicating that carbon atoms of benzene nucleus could be eventually converted to inorganic carbons. Meanwhile, it was also clarified that chlorine atoms in the organics were liberated as chloride ions. In addition, it was revealed that the disappearance of monochlorophenols obeyed the first-order rate law, depending on the isomeric structures.     

吡啶硫酮锌对水生生物的急性毒性(Acute Toxicity Effects of Zinc Pyrithione on Aquatic Organisms)

在没有下水处理设施的地区,去屑洗发香波中所含有的吡啶硫酮锌(zinc pyrithione,ZPT)随着生活废水被直接排放到河中.为了考察流入河中的ZPT对水生生物的影响,设想ZPT最终被底质吸附,在添加和未添加底质两种试验条件下,采用静水生物测试法对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬进行了室内急性毒性试验.结果表明,添加底质时,ZPT对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬48h的半致死浓度LC50分别为0.06、0.09、0.27、0.07和5.05mg·L-1;未添加底质时,ZPT对麦穗鱼、青鳉、泥鳅鱼、直突摇蚊亚科二龄幼虫、河蚬48hLC50分别为0.10、0.11、0.22、0.12和5.34mg·L-1.统计结果显示,添加与未添加底质,ZPT对上述供试生物的48hLC50值无显著差异(p>0.05).根据我国相关标准判定ZPT对麦穗鱼、青鳉、直突摇蚊亚科2龄幼虫属剧毒物质.