Hydrocarbon stress response of four tropical plants in weathered crude oil contaminated soil in microcosms

Responses to hydrocarbon stress of four tropical plants Panicum maximum, Zea mays, Centrosema sp. and Pueraria sp. grown in crude oil contaminated soils (1%, 5% and 10% w/w) were evaluated in a green house. Plants’ percentage survival, shoot heights, biomass development, and phytotoxicity susceptibility were used as indicators of growth, stress response and hydrocarbon tolerance. Relative to control, shoot heights and biomass of plants reduced with increasing hydrocarbon concentration, but 1% w/w oil-in-soil, stimulated shoot heights (5.9% and 6.4%) and weights (21.9% and 2.3%) in P. maximum and Centrosema sp. respectively. P. maximum tolerated the contaminant stress with biomass yields of 113% and 57% of control respectively in 1% and 10% w/w oil-in-soil. All the plants had 100% survival in 1% w/w, but considerably reduced survival in 10% w/w oil-in-soil. These results show that P. maximum has great potential for phytoremediation of petroleum contaminated soil.     

公私合营(PPP)项目市场需求风险分担研究

对PPP项目市场需求风险的影响因素、分担偏好、参与者的管理能力等问题进行探讨,以实例提出PPP项目市场需求风险完全由政府承担、政府与私人投资者共同承担及私人投资者承担的三种模式。在此基础上提出风险分担中政府所应承担的责任,以及市场分担与项目竞争强度的关系等观点,以期为政府后续PPP项目市场需求风险的管理提供参考和借鉴。     

Polychlorinated naphthalenes in air and snow in the Norwegian Arctic: a local source or an Eastern Arctic phenomenon?

PCNs were measured in air and snow during separate field campaigns at Ny-Alesund (April 2001) and Troms? (February/March 2003) in the Norwegian Arctic. Air concentrations ranged from 27 to 48 and 9 to 47 pg sigmaPCN m(-3) for Ny-Alesund (n=6) and Troms? (n=10), respectively. These concentrations (including the tri-chlorinated naphthalenes) greatly exceeded concentrations previously measured in the Canadian Arctic, but did fall within the upper range of concentrations observed over the eastern Arctic Ocean and regional seas. Local sources appear to be affecting concentrations observed at both sites, with the presence of several hexa-chlorinated naphthalenes at Troms? probably attributed to local/regional sources. Use of air mass back trajectories at Troms? revealed that background air concentrations in the Norwegian Arctic are likely to range between <9 and 20 pg sigmaPCN m(-3) and that contemporary concentrations derived close to potential sources (i.e. arctic towns) may equal or exceed those of PCBs. The mean concentration in surface snow was 350 and 240 pg sigmaPCN L(-1) (meltwater) (or 0.014 and 0.01 pg g(-1) (snow)) at Ny-Alesund and Troms?, respectively. The wide variation in concentrations observed between fresh snowfalls could be explained by different snow densities (as a surrogate of snow surface area), rather than attributed to varying air concentrations. A statistically significant inverse relationship was found between snow density and concentrations of tri- to penta-chlorinated homologues and compliments similar findings for the polychlorinated biphenyls (PCBs). This suggests that the vapour-sorbed quantity changes rapidly with snow ageing/compaction; with implications for the fate of these chemicals in the Arctic.     

Cobalt powdersintering industry (stone cutting diamond wheels): a study of environmental-biological monitoring, workplace improvement and health surveillance

This communication deals with an aspect of occupational hygiene in a factory producing granite cutting diamond wheels by sintering, in moulds, of fine cobalt powder. The factory has been studied between 1988 and 1991; the Department of Preventive and Occupational Medicine of the Local Sanitary Unit of Reggio Emilia has followed the evolution of the local exhaust ventilation equipment supplied by the employer in that period. At the same time, the following measurements and observations were carried out: (a) cobalt exposure by personal sampling, (b) airborne cobalt measurements by area sampling, (c) biological monitoring of cobalt in urine, (d) health surveillance.     

Earthquake-induced net section fracture in brace connections — experiments and simulations

Results from six tests, finite element simulations and a synthesis of previous test programs on slotted end bracing connections are presented. The main objective of the research is to examine the deformation capacity of these connections, with the ultimate objective of minimizing the requirement for net section reinforcement that is often inconvenient from the perspective of fabrication. The experiments and simulations feature commonly used pipe specimens and end details. The main parameters investigated include the gusset plate thickness, the slot length and introduction of a wrap-around weld that eliminates the reduced section at the edge of the gusset plate. The results indicate that even without reinforcement, the connections offer adequate to excellent deformation capacity if they are provided with the wrap-around weld or if the net section strength is larger than the gross yield strength. This may be achieved in situations where shear lag in the connection is minimal, and where the area reduction due to the slot is small relative to the gross area. Design considerations are presented along with limitations of the study.     

Human response to blast-induced vibration and air-overpressure: an Indian scenario

Ground vibration (V_max) and air-overpressure/noise (p) are some of the negative effects of blasting. The associated human annoyance and complaints are expected to show an increasing trend in the future as there is no economically viable alternative to blasting in mines in India.A study of the human response to blasting in four mining localities across India has shown that the response is not simply political, as frequently assumed. It has been found that irrespective of those questioned, a basic concern for the safety of property was the main response. There was a greater response from the middle-aged and middle-educated while fewer women than men responded. Assuming that a 100% negative response from the inhabitants will translate into complaints, a methodology is suggested to take account of the human response criteria when considering blasting within 400 m of habitations.     

CROSS - a Program for Determination of Coefficients of Subgrade Reaction

Soil Mechanics and Foundation Engineering -