A particle induced X-ray emission (PIXE) system was improved for the analysis of the very thin surface of a material. We developed a precise low-energy proton irradiation system with a compact X-ray detector set near a sample. The energy of protons was varied from 30 to 100 keV for the analysis of the thin surface of a sample. It was confirmed from experimental results on some standard samples that the present PIXE analysis system had sufficient statistics on the counting for characteristic X-rays. Also this PIXE system was successfully applied to the analysis of the thin surface of the multi-layer films and the particulate sample.
Recently, the decrease in the number of farm households in rural areas has resulted in difficulties in the maintenance of irrigation and drainage canals which run through settlements. Changes in lifestyle, degradation of water quality and lack of flow in canals have been the main contributory factors in the decline of multi-functionality of water use. In this study, residents' perception of the multi-functional roles of irrigation water in the Kohoku Region was evaluated through a questionnaire, which included questions related to the contingent valuation method. Furthermore, measurements of water quality and flow in the canals through the settlements were conducted. The results indicated that residents' appreciation of irrigation water in the upper settlements was different from that of the lower settlements; however, there was little difference in appreciation between farm households and non-farm households. It seems that it is of paramount importance to promote better residents' understanding of irrigation water as a common asset in order to address the maintenance problems of canals.
For the emission gas concentration measurement of sublimable gas phase boron compounds, the optimal collector material applied to the inside stack sampler (the type-1 stack sampler developed in our previous article) was examined. The collection efficiency of alkali impregnated filter paper of calcium carbonate and magnesium hydroxide was investigated by the use of artificial stack. It was revealed that calcium carbonate filter paper have a high collection efficiency and fully applicable to the type-1 stack sampler equally to potassium carbonate filter paper examined in our previous study. However, magnesium hydroxide filter paper is not suitable for the collection agent.
The concentrations of ozone (O3), nitrogen oxides (NOX) and sulfur dioxide (SO2) and size-separated aerosol number concentrations were measured in Toyama city during the spring and early summer in 2007. High concentrations of O3 (› 100 ppb) were observed on 8-9 and 23 May. Especially, on the 9 May event, O3 concentration increased up to 120 ppb in the afternoon, and a photochemical oxidant advisory was announced in Toyama. The number concentrations of coarse particles (› 2.0 μm) which might have been mainly derived from soil dust, were also high on 8-9 May, on the other hand, the coarse particles concentrations were low on 23 May. The backward trajectory analysis showed that the air mass on 9 May in Toyama originated from the arid areas and the polluted regions the Asian continent, whereas the air pollution might have been transported from the western parts of Japan.
Coating of hydroxyapatite (HAp) on the surfaces of organic polymer substrates through a biomimetic process was attempted to fabricate a novel adsorbent of harmful volatile organic compounds, and its ability of the adsorption of formaldehyde was evaluated. The surfaces of organic polymer substrates were successfully coated with biomimetic HAp layer, when they contained carboxyl groups in their structure after exposure to a simulated body environment. Putting the biomimetic HAp coated on the organic polymer in formaldehyde atmosphere resulted in a significant decrement in the concentration of formaldehyde, in comparison with the calcined HAp or the activated carbon. This phenomenon may be attributed to the achievement of high specific surface area and low crystallinity of the biomimetic HAp. Such a material can be a candidate for an efficient adsorbent to remove formaldehyde and its related harmful gases.
Carbon sequestration by large-scale afforestation in arid regions is expected to be a countermeasure against global warming. In much of arid areas in Western Australia, there is a water-impermeable layer near the ground surface which is known as hardpan and inhibits tree growth. For successful afforestation in such arid areas, the soil structure must be modified to enable tree growth. Although it was demonstrated that blasting with explosives is effective in breaking the hardpan, the amounts of explosives used must be reduced and the blasting method must be optimized to reduce the carbon emission and carbon fixation cost involved in the afforestation process. We therefore conducted a hardpan blasting experiment with different patterns of packing explosives in an arid area in Western Australia. ANFO prills or ANFO prills diluted with polystyrene beads were packed in vertical holes 3.6 m deep and 96 mm in diameter drilled into the hardpan. Explosives were packed at varying depths. A soil zone necessary for tree growth was able to be created by hardpan blasting using half as much explosive as that used in the previous experiment. Furthermore, the results suggested that the amount could be reduced to less than one half.
On 22 and 28 July 2007 we took samples from Lake Tilap, in the Rakumpit subdistrict of Central Kalimantan, Indonesia, to investigate the concentrations of mercury in water, sediment, phytoplankton, zooplankton, and fish species. Mercury concentrations in the samples were measured by heating evaporation mercury measurement equipment. Mercury was not detectable in surface water sample (≤ 0.002 μg/L), and level in sediment sample was 0.030 μg /g. Phytoplankton at depths of 7.5, 3.5, and 0.5 m contained 0.008 μg /g, 0.008 μg /g, and 0.051 μg /g, respectively. Overall, zooplankton had the highest concentrations of mercury (0.016-0.079 μg /g). Nine fish species were sampled. The total mercury concentration in fish muscle tissues ranged from 0.034 to 0.426 μg /g, and the juah (Luciosoma trinema) had the highest concentration.
New 8-hydroxyquinoline derivatives have been synthesized efficiently via Mannich condensation and subsequently tested for solubility and Cu(II) ion extraction in supercritical carbon dioxide (Sc-CO2). All of newly synthesized compounds could disperse easily into Sc-CO2 and show the moderate extraction efficiency for Cu(II) ion from solid matrix. It was concluded that these compounds could be potentially used as chelating agents for the Sc-CO2 metal extraction.
For control of non-point pollutants in Han River, the required method to become with nature is riparian buffer zone (RBZ) or riparian buffer waterside. RBZ is habitats of living organism and it is to improve water quality setting up and management. But the study of riparian buffer zones has not been achieved yet. The object of the study is to establish efficient setting of riparian buffer zone for increase of self-purification, ability to intercept non-point pollutants and preservation of habitats of living organism. The study focused on existing experimental site's development and complement. Experimentation and analysis of removal effect of non-point pollutants has also been preceded. A location of the Experiment is Nam Han River (Byung San-Ri, Yang Pyong-Gun, Gyeong Gi-Do) which is included in Han River water system. The area was divided into 5 land cover sectors: grass, reed, pussy willow, mixed (grass + pussy willow) and natural zone to compare effectiveness of vegetation. Water samples from four points and samples each sector have been collected in different widths and depths (4 points in each sector). And the pollutant removal efficiency by sectors with different plant species was yielded through influent with one of each sample.
In this study, degradation of TNT under different metabolic regimes of slurry phase bioreactor for TNT-contaminated soil treatment was evaluated. The most rapid degradation of TNT was observed in aerobic treatment at the early stage of operation and its degradation efficiency was 71.5% until 60 days. After 200 days of operation, however, degradation efficiency was 93.2%. This was relatively low compared to anaerobic and anaerobic/aerobic treatments which showed degradation efficiencies of 97.0% and 95.0%, respectively. In anaerobic/aerobic treatment, the degradation of TNT was not significantly enhanced by subsequent aerobic stage compared to anaerobic treatment alone.
The Asian dust phenomena, Kosa, have possibility to carry the microbial particles (Kosa bioaerosol) influencing the microbial habitats and the human health in Japan. In this study, the bioaerosol were collected at 600 m and 2 m above ground in Kanazawa city at the Kosa coming season, April in 2007. In the culture medium produced using seawater and lake water, the bioaerosol at 600 m indicated the microbial growth only in the seawater medium, but no growth in the lake water medium. The bacteria in bioaerosol at 2 m grew in both of the seawater and lake water media. The halophilic bacteria would maintain viable activities in the atmosphere. When the bioaerosol at 2 m was inoculated to the culture media including NaCl at some ranges of concentrations, the microbial growth was higher in this order of 0%, 3%, and 10% of NaCl concentrations, and no growth was detected in the 20% NaCl medium. According to the DGGE (denaturing gradient gel electrophoresis) analysis, same bacterial species would be included in the every NaCl concentration of culture medium, and other bacterial species could grow only in the culture medium with 3% or 10% NaCl concentrations. Therefore, the halophilic or halotolerant bacteria would survive in the aerosol at 2 m above ground, and may be related to the long-distant transfer of microbial population. The approach targeting the halobacteria will provide valuable information about the microbial transport across the ground-atmospheric area.
A prototype of a simple, structured fishway was developed for the regeneration of an aquatic network around a paddy field. The fishway is compact, lightweight, and made of common materials with a groove and weir system. The groove and weir system is characteristically adaptable to various circumstances through the application of weirs of appropriate shapes and sizes. It took eight people about two hours to install the fishway in a channel and less than one hour to remove it. The measurement of the drops and velocities of the fishway flow in both the laboratory and on site demonstrated that the flow would enable fish passage. The fishway is efficient for fish passage from a hydraulics viewpoint and sufficiently practical with regard to implementation.