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11.
Zheng LI Rong QI Wei AN Takashi MINO Tadashi SHOJI Willy VERSTRAETE Jian GU Shengtao LI Shiwei XU Min YANG 《Frontiers of Environmental Science & Engineering》2015,9(3):534
In this study, the performance of nitrogen and phosphorus removal in a full-scale closed-loop bioreactor (oxidation ditch) system was simulated using the ASM2d model. Routine data describing the process for two years were compiled for calibration and validation. To overcome the identifiability problem, the classic Bayesian inference approach was utilized for parameter estimation. The calibrated model could describe the long-term trend of nutrient removal and short-term variations of the process performance, showing that the Bayesian method was a reliable and useful tool for the parameter estimation of the activated sludge models. The anoxic phosphate uptake by polyphosphate accumulating organisms (PAO) contributed 71.2% of the total Poly-P storage, which reveals the dominance of denitrifying phosphorus removal process under the oxygen limiting conditions. It was found that 58.7% of the anoxic Poly-P storage and denitrification by PAO in the reactor was achieved in the aerated compartment, implying that the PAO’s anoxic activity was significantly stimulated by the low dissolved oxygen (DO) level in this compartment due to the oxygen gradient caused by brush aerator. 相似文献
12.
Web spiders are considered to have expanded their habitats from dim to bright environments during the evolutionary history.
Because they are sedentary predators exposed to the sun, they may have developed a suite of adaptive traits to cope with thermal
stress. We examined the critical thermal maximum, spectral reflectance of solar energy by the body surface, and surface–volume
ratio (SVR) for 11 spider species. Analysis of the four genera having a pair of species inhabiting both bright and dim environments
showed that species in bright environments exhibited higher lethal temperatures, but spectral reflectance and SVR did not
differ. Independent contrasts using the 11 species indicated that critical thermal maximum was positively correlated with
spectral reflectance and spectral reflectance was negatively correlated with SVR. These results suggest that physiological
tolerance to high temperatures and a biophysical mechanism to reduce heat gain evolved jointly during the history of habitat
expansion in araneoid spiders. 相似文献
13.
Tadashi Hasegawa Kakeru Usuba Soichiro Kondo Yutaka Maeda 《Environmental Chemistry Letters》2008,6(2):107-111
Here, we show that association of stilbene molecules is facilitated by water on silica gel because of hydrophobic interaction
and photodimerization becomes the main photochemical process. Irradiation of trans-stilbene (t-1) on silica gel gives cis-stilbene (c-1), phenanthrene (2), benzaldehyde (3), and dimers r-ctt-4 and r-tct-4. The yields of the dimers increase and those of 2 and 3 decrease with an increase in the amount of t-1 loaded on silica gel. Atmospheric oxygen is responsible for the formation of 2 and 3. The yields of the dimers also increase with an increase in the water on a silica-gel surface and change drastically at the
point where the percentage of water to silica gel is around 25 wt%. All active sites on a silica-gel surface would be covered
completely with 25 wt% of water. 相似文献
14.
Remediation of cadmium contamination in paddy soils by washing with chemicals: selection of washing chemicals 总被引:3,自引:0,他引:3
Makino T Sugahara K Sakurai Y Takano H Kamiya T Sasaki K Itou T Sekiya N 《Environmental pollution (Barking, Essex : 1987)》2006,144(1):2-10
The efficiencies of neutral salts, strong acids, and chelates were tested for extracting cadmium (Cd) from three paddy soils. The higher the selectivity of the cations of the added neutral salts toward soil adsorption sites, the lower the pH in the extracts and the more soil Cd could be extracted. In addition, soil carbon and nitrogen contents and mineral composition were closely associated with the amount of Cd extracted. Calcium chloride and iron(III) chloride were selected as wash chemicals to restore Cd-contaminated paddy soils in situ. Washing with calcium chloride led to the formation of Cd chloride complexes, enhancing Cd extraction from the soils. The washing also substantially decreased soil levels of exchangeable and acid-soluble Cd, which are the major forms of bioavailable Cd for rice (Oryza sativa L.). The optimum conditions for in situ soil washing were also determined for calcium chloride. 相似文献
15.
Risky Ayu Kristanti Masahiro Kanbe Tadashi Toyam Yasuhiro Tanak Yueqin Tang Xiaolei Wu Kazuhiro Mori 《环境科学学报(英文版)》2012,24(5):800-807
We investigated the biodegradation of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP) in the rhizosphere of Spirodela polyrrhiza plants by conducting degradation experiments with three river water samples supplemented with each nitrophenol (NP). We then isolated NP-degrading bacteria both from the S. polyrrhiza roots and from the river water. In the river water samples, removal of the three NP was accelerated in the presence of S. polyrrhiza plants. The three NPs persisted in an autoclaved solution with sterile plants suggests that NP removal was accelerated largely by bacterial NP biodegradation rather than by adsorption and uptake by the plants. We isolated 8 strains of NP-degrading bacteria: 6 strains from the S. polyrrhiza roots and 2 strains from river water without the plants. The 2-NP- and 2,4-DNP-degrading bacteria were isolated only from the S. polyrrhiza roots. The 4-NPdegrading bacteria different from those isolated from the river water samples were also found on S. polyrrhiza roots. The 2-NP- and 4-NP-degrading strains isolated from the roots utilized the corresponding NP (0.5 mmol/L) as the sole carbon and energy source. The 2,4-DNP-degrading strains isolated from the roots showed substantial 2,4-DNP-degrading activity, but the presence of other carbon and energy sources was required for their growth. The isolated NP-degrading bacteria from the roots must have contributed to the accelerated degradation of the three NPs in the rhizosphere of S. polyrrhiza. Our results suggested that rhizoremediation with S. polyrrhiza may be effective for NP-contaminated surface water. 相似文献
16.
Max A. Moritz Tadashi J. Moody Lori J. Miles Matthew M. Smith Perry de Valpine 《Environmental and Ecological Statistics》2009,16(2):271-289
Statistical characterization of past fire regimes is important for both the ecology and management of fire-prone ecosystems.
Survival analysis—or fire frequency analysis as it is often called in the fire literature—has increasingly been used over
the last few decades to examine fire interval distributions. These distributions can be generated from a variety of sources
(e.g., tree rings and stand age patterns), and analysis typically involves fitting the Weibull model. Given the widespread
use of fire frequency analysis and the increasing availability of mapped fire history data, our goal has been to review and
to examine some of the issues faced in applying these methods in a spatially explicit context. In particular, through a case
study on the massive Cedar Fire in 2003 in southern California, we examine sensitivities of parameter estimates to the spatial
resolution of sampling, point- and area-based methods for assigning sample values, current age surfaces versus historical
intervals in generating distributions, and the inclusion of censored (i.e., incomplete) observations. Weibull parameter estimates
were found to be roughly consistent with previous fire frequency analyses for shrublands (i.e., median age at burning of ~30–50 years
and relatively low age dependency). Results indicate, however, that the inclusion or omission of censored observations can
have a substantial effect on parameter estimates, far more than other decisions about specifics of sampling.
相似文献
Max A. MoritzEmail: |
17.
Shinya Inazumi Tadashi Wakatsuki Masakatsu Kobayashi Makoto Kimura 《Journal of Material Cycles and Waste Management》2010,12(1):50-56
Water-swelling material (WSM) is a fluid sealant obtained by blending high-absorbency polymer, a filler, and a solvent by
using a synthetic resin elastomer as the base material. In this research, we studied experimentally the composition of WSM,
the extent of swelling, the strength of the WSM and the long-term performance of the swelling material used as a jointed water
cutoff treatment material at waste landfill sites. One of the results was that adjusting the degree of etherification of the
high-absorbency polymer, which is a component of the WSM, and the resin content of the synthetic elastomer contributed to
improvement of the swelling of the sealant and the strength of the swelling material. Further, in long-term tests, the strength
of the WSM tended to become stabilized and it was confirmed that it had sufficient pressure resistance for use in coastal
landfill sites, where its application as a water cutoff treatment material is being considered. 相似文献
18.
19.
Principal Component Analysis (PCA) is a convenient tool used in aggregating the indicators of sustainable development and providing indices where different weights are assigned to the various indicators. There are, however, problems in interpreting of indices, especially if time series data are used. This study explores the feasibility of applying recent developments in PCA of time series using Philippine data. We present the comparative advantages of SPCA (Sparse Principal Component Analysis) relative to averaging of an adequacy/inadequacy index and PCA in index construction from various indicators of sustainable development in the Philippines in terms of usefulness and validity of indices being developed. SPCA can attain sparse and non-overlapping loadings without losing a large amount of explained variance compared to PCA. Because of the non-overlapping contribution of variables in SPCA components, indices can have clear and mutually exclusive meanings, facilitating interpretation. Even with a more complicated algorithm, reduced dimensions and simpler interpretation of indices justify the advantages of SPCA over PCA in index construction. The indices are interpreted in terms of the milestone of sustainability in the Philippines. The resulting indices provide an adequate summary of the sustainable indicators and evidence of the importance of leadership and political will in sustainable development. 相似文献
20.
Development of a catalytic cracking process for converting waste plastics to petrochemicals 总被引:2,自引:0,他引:2
Junya Nishino Masaaki Itoh Tadashi Ishinomori Nobuhiko Kubota Yoshio Uemichi 《Journal of Material Cycles and Waste Management》2003,5(2):89-93
The catalytic degradation of polyolefin using H-gallosilicates was examined using a bench-scale reactor (0.8kg/h) with semicontinuous feeding and the following plastics: (1) low-density polyethylene (LDPE) pellets; (2) linear low-density polyethylene (L-LDPE) pellets; (3) high-density polyethylene (HDPE) pellets; (4) polypropylene (PP) pellets; (5) polyolefin obtained from pulverized industrial waste plastics. The yields of liquid compounds from these materials, which were aromatics in most cases, ranged from 55wt% to 68wt%. With an increase in the ratio of total reactant to catalyst, the liquid yield remained the same. Yields of benzene, toluene, and xylenes (BTXs) decreased rapidly to below 50wt% at a ratio of more than 30. Differences in this ratio for BTXs were always small and were independent of the material. Only about half of the gas product was propane with a fresh catalyst. When the experiments were repeated, propylene, isobutane, and isobutene were found to increase. 相似文献