The Influence of Synoptic-scale Air Flow and Local Circulation on the Dust Layer Height in the North of the Taklimakan Desert

The present study investigates the influences of synoptic-scale air flows and local wind circulations on the dust layer height (DLH) in the Taklimakan Desert, based on lidar observations performed in the north of the desert in March 2003. The DLH fluctuates approximately every three days between 2500 m (above sea level) and 5000 m, including diurnal variations. Meteorological analyses and numerical simulations show that the three-day fluctuation of DLH corresponds with variations in synoptic-scale air flows over the Taklimakan Desert, and the diurnal variations are linked to downdrafts and updrafts that are formed over the north of the desert as part of local circulations. When strong northerly winds prevail in the upper troposphere and a developed valley wind blows toward the Tienshan Mountains in the lower troposphere, the downdrafts strengthen in the middle troposphere over the north of the desert, lowering the DLH to about 2500 m. In contrast, the DLH rises to about 5000 m when the updrafts develop between strong southerly winds in the upper troposphere and a developed mountain wind blowing from the Tienshan Mountains. Simulations for the local circulation behavior without the presence of the Tienshan Mountains demonstrate that the valley and mountain winds on the southern slope of the Tienshan Mountains control the intensity of the downdrafts and updrafts, thereby influencing the DLH over the north of the Taklimakan Desert.     

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.     

Molecular size as a limiting characteristic for bioconcentration in fish

The relationships between the bioconcentration factor (BCF) of chemicals in fish and their size, as characterized by molecular weight (MW), effective cross sectional diameter (Deff), and maximum diameter (Dmax) have been investigated using an experimental data set of 737 new and 441 existing chemicals monitored by the Japanese Chemical Substances Control Law (CSCL). Substances with BCF > or = 5000 (very high bioconcentration potential) typically have MW < 550, Deff < 1.1 nm and Dmax < 2.0 nm, respectively and the substances with BCF > or = 1000 (high bioconcentration potential) have MW < 550, Deff < 1.4 nm and Dmax < 2.9 nm, respectively Therefore, the previously suggested threshold values for Deff (0.95 nm) and Dmax (1.5 nm) used for discriminating between bioconcentrative and non-bioconcentrative substances were found to be somewhat small. We found that many substances with BCF > or = 1000 and Dmax > or = 1.5 nm have Deff < 0.95 nm.     

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.     

Investigation of perfluoroalkyl carboxylic and sulfonic acids in leachates from industrial and municipal solid waste landfills,and their treated waters and effluents from their closest leachate treatment plants

Journal of Material Cycles and Waste Management - Per- and polyfluoroalkyl substances (PFASs) are used in products, such as aqueous film-forming foam and fluorochemical surfactants, because of...     

Arsenic,selenium, and chromium speciation in fly ash

Journal of Material Cycles and Waste Management - Arsenic (As), selenium (Se), and chromium (Cr) are harmful to humans at certain concentrations, and can possibly be eluted from coal ash (fly ash)...