密闭压力容器小型循环试验结果

在联合国危险品运输试验和标准建议书(桔皮书)中,系列E涉及评价物质在密闭容器中对剧烈加热的热爆炸敏感性的标准。但是人们一直希望并致力于发展一种定量,可靠,重复性好的方法来评价物质的热爆炸敏感性。本文介绍了一种小型密闭压力容器循环试验的研究及其作为一种筛选试验向联合国提案的最新进展。实验结果表明,几种物质在不同实验室的重复性非常好,其(dP／dt)max平均偏差率在20％以内,表明该小型密闭压力容器作为评价物质热反应危险性的测试方法具有较高的可靠性。     

Roadside Particulate Air Pollution in Bangkok

Abstract

Airborne fine particles of PM_2.5-10 and PM_2.5 in Bangkok, Nonthaburi, and Ayutthaya were measured from December 22, 1998, to March 26, 1999, and from November 30, 1999, to December 2, 1999. Almost all the PM₁₀ values in the high-polluted (H) area exceeded the Thailand National Ambient Air Quality Standards (NAAQS) of 120 μg/m³. The low-polluted (L) area showed low PM₁₀ (34–74 μg/m³ in the daytime and 54–89 μg/m³ at night). PM_2.5 in the H area varied between 82 and 143 μg/m³ in the daytime and between 45 and 146 μg/m³ at night. In the L area, PM_2.5 was quite low both day and night and varied between 24 and 54 μg/m³, lower than the U.S. Environmental Protection Agency (EPA) standard (65 μg/m³). The personal exposure results showed a significantly higher proportion of PM_2.5 to PM₁₀ in the H area than in the L area (H = 0.80 ± 0.08 and L = 0.65 ± 0.04).

Roadside PM₁₀ was measured simultaneously with the Thailand Pollution Control Department (PCD) monitoring station at the same site and at the intersections where police work. The result from dual simultaneous measurements of PM₁₀ showed a good correlation (correlation coefficient: r = 0.93); however, PM levels near the roadside at the intersections were higher than the concentrations at the monitoring station. The relationship between ambient PM level and actual personal exposures was examined. Correlation coefficients between the general ambient outdoors and personal exposure levels were 0.92 for both PM_2.5 and PM₁₀.

Bangkok air quality data for 1997–2000, including 24-hr average PM₁₀, NO₂, SO₂, and O₃ from eight PCD monitoring stations, were analyzed and validated. The annual arithmetic mean PM₁₀ of the PCD data at the roadside monitoring stations for the last 3 years decreased from 130 to 73 μg/m³, whereas the corresponding levels at the general monitoring stations decreased from 90 to 49 μg/m³. The proportion of days when the level of the 24-hr average PM₁₀ exceeded the NAAQS was between 13 and 26% at roadside stations. PCD data showed PM₁₀ was well correlated with NO₂ but not with SO₂, suggesting that automobile exhaust is the main source of the particulate air pollution. The results obtained from the simultaneous measurement of PM_2.5 and PM₁₀ indicate the potential environmental health hazard of fine particles. In conclusion, Bangkok traffic police were exposed to high levels of automobile-derived particulate air pollution.     

Respiratory uptake kinetics of neutral hydrophobic organic chemicals in a marine benthic fish, Pseudopleuronectes yokohamae

We investigated the respiratory uptake kinetics of polychlorinated biphenyls (PCBs), organohalogen pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and 2,2′,4,4′-tetrabrominated diphenyl ether (BDE #47) in a marine benthic fish, Pseudopleuronectes yokohamae. The respiratory uptake efficiencies (E_W) of the chemicals, of which there have been no reports for the majority of persistent organic pollutants (POPs), were obtained by measuring the respiratory uptake rate constants (k₁) and the oxygen consumption rates of fish. Fish were exposed to water in which these chemicals were dissolved at environmentally relevant concentrations for 28 d, followed by 168 d of depuration in clean seawater. The k₁ and E_W values for 99 compounds were obtained, and they ranged from 2000 to 42 000 L kg-lipid⁻¹ d⁻¹ and from 0.060 to 1.3, respectively. The E_W values of the chemicals, except for PAHs, tended to increase with increasing values of the log octanol–water partition coefficients (K_OW) of the chemicals up to a log K_OW of 5. For log K_OW in the range 3–5, the E_W values in this study were much lower than those in a published study (about one-third). As a result of analysis by a two-phase resistance model, the resistance of transport rates to the lipid phase in this study was lower than was the case in the published study. These findings indicate that the E_W predicted by the published study for log K_OW in the range 3–5 may differ among fish species and water temperature, and further study is needed.     

Evaluation of diffusive gradients in thin films technique (DGT) for measuring Al, Cd, Co, Cu, Mn, Ni, and Zn in Amazonian rivers

Studies concerning the lability and bioavailability of trace metals have played a prominent role in the search for contamination of water resources. This work describes the first application yet of the diffusive gradients in thin films technique (DGT) to the determination of the fraction of free plus labile metals in waters from the Amazon Basin. Due to the complexity of the use of DGT for samples with low ionic strength and high organic matter content (characteristic of Amazonian rivers), a new analytical procedure was developed. The method is based on the determinations of apparent diffusion coefficients (D_ap) in the laboratory, by performing deployments in samples collected in the corresponding sites of study. The D_ap thereby determined is then used for in situ measurements. The suitability of the proposed approach for determination of labile Al, Cd, Co, Cu, Mn, Ni, and Zn in the Amazon River and Rio Negro (English: Black River) was evaluated. Except for Co, Mn (in a deployment at Rio Negro), Ni and Zn (in a deployment at Amazon River), labile in situ measurements were lower or similar to dissolved concentrations, indicating suitability of the proposed approach.     

Aerosol optical properties derived from imultaneoussunphotometer and aureolemeter measurements in Lhasa

In order to obtain some aerosol properties in Tibetan Plateau atmosphere, simultaneous measurements of aerosols by use of a sunphotometer and an aureolementer were performed in the summer of 1998 in Lhasa(29.65°N, 91.13°E). Optical depth, volume size distribution and phase-function of aerosols were obtained from the measurements. Religious activities can have an effect on optical depth in Lhasa. The daily average aerosol optical depth(λ相似文献   

Relationship between indoor and outdoor carbonaceous particulates in roadside households

Concentrations of particulate matter (PM) and carbonaceous particulates in indoor and outdoor air at roadside private households were measured in Osaka, Japan. The particulate samples were collected on filters using a portable AND sampler capable of separating particles into three different size ranges: over 10 microm, 2-10 microm (coarse) and below 2 microm (fine) in aerodynamic diameter. The filters were weighed and then analyzed for elemental carbon (EC) and organic carbon (OC) by thermal oxidation using a CHN CORDER. The results showed that indoor fine PM concentration is considerably affected by fine EC and the fine EC in indoor air is significantly correlated to that in outdoor air, r=0.86 (n=30, p<0.001). A simple estimation from EC content ratio in diesel exhaust particles indicated that about 30% of indoor particulates of less than 10 microm (PM10) were contributed from diesel exhaust. Additionally, the size characteristics of outdoor PM at roadside and background sites were examined using Andersen Cascade Impactors.     

Snake-directed mobbing by the Formosan squirrel Callosciurus erythraeus thaiwanensis

Summary The Formosan squirrel Callosciurus erythraeus thaiwanensis was often observed mobbing the snake Elaphe climacophora. A total of 36 natural and 21 experimentally induced mobbings were observed and analyzed. The number of attending squirrels per mobbing event varied from one to seven, and 84% of observed mobbings were performed by more than one individual. The duration of a mobbing bout increased directly with the number of assembled mobbers. In 68% of cases, one adult female was one of the mobbers; there was never more than one female per mob. The number of assembled males per mob varied from 0 to 5; 40% of the mobbings involved two or more males. This difference is correlated to a difference in spacing patterns of both sexes; female home ranges were distributed exclusively, whereas male home ranges overlapped each other. Females mated with multiple males whose home ranges overlapped theirs. Female's reproductive status (conception, lactation, and weaning) affected their intensity of response to the playback of mobbing calls, females in pup-rearing period being the most sensitive. One function of the mobbing appears to be defense of the young against snake predation. Females mobbed more intensively and longer than males. Males that had resided at the study site for at least 1 year tended to mob more frequently than intruders.     

Chitin biodegradation and wound healing in tree bark tissues

Chitin biodegradation and wounded bark tissue healing were demonstrated in several evergreen and deciduous trees by dressing with a sheet of chitin-containing films or sponges. Chitinase activities in the tree bark tissues around the wounds were enhanced by this treatment up to four times those of the untreated wounds. Significant seasonal changes of chitinase activities were observed with the bark and leaf tissues of deciduous trees, but few with those of evergreen trees. A sheet of chitin films implanted or dressed in the tree bark tissues was biodegraded within 4 to 24 weeks after implantation and was assimilated into the wounded bark tissues, resulting in the stimulation of the wounded bark tissue healing.     

Identification of a dynamic lake model by the group method of data handling: An application to lake ontario

A revised algorithm of the group method of data handling (GMDH) is used to model and identify water quality dynamics in Lake Ontario. The state variables in the model are corrected chlorophyll a, volume-averaged over the top 20 m, and soluble reactive phosphorus in three layers, 0–20 m, 20–40 m and from 40 m to bottom. Inputs are the average quarterly temperatures for each layer and the total phosphorus loadings. Two kinds of model are developed: recursive and iterative; they are used to simulate long-term predictions for three different hypothetical rates of phosphorus loading. Results show that GMDH can be usefully employed to develop lake models with a very low expense of manpower and computer time. This exercise compares well with other large-scale modelling efforts of Lake Ontario, even if necessarily more limited in scope.     

有机过氧化物热分解激烈度的危险性评价方法

采用小型密闭式压力容器试验(MCPVT)测定了有机过氧化物热分解产生的压力举动，根据压力(P)及其上升速度(dP/dt)考察了有机过氧化物热分解激烈度，并与压力容器试验(PVT)进行比较，寻找MCPVT与PVT之间的关系，给出了热分解激烈度的评价方法。实验结果表明，除热分解前即产生蒸发的物质外，MCPVT的最大压力上升速度(dP/dt)max与PVT的最小孔径(d)有良好的相关性。同时指出，对分解前产生蒸发的物质，不适合用PVT进行热分解激烈度的评价，应采用MCPVT进行评价。