Advanced Materials Research Vols. 610-613

Abstract: The use of CdTe quantum dots (QDs) as fluorescent probes for detection of copper(II) in seawater was evaluated, and the relationship between the size of CdTe QDs and fluorescent response in seawater was investigated. The fluorescence intensity of CdTe QDs was quenched linearly as the concentration of copper(II) increased, and the quenching efficiency increased as the size of the CdTe QDs decreased. The smaller CdTe QDs (emission peak at 518 nm, average diameter of ~2.1 nm) achieved a detection limit of copper(II) of 0.48 μg L−1 under optimal experimental conditions. No significant influence was found for pH in the range from 7.0 to 9.0 in seawater. In contrast, the emission maxima of the CdTe QDs exhibited a slight red shift and the intensity of fluorescence decreased significantly as salinity was increased. Based on the performance of CdTe QDs in this study, small CdTe QDs display enormous potential for detection of copper(II) in seawater.

Abstract: In order to predict the biochemical oxygen demand (BOD) concentration of Haihe River, a more accurate hybrid model, based on combined principal component regression (PCR) and artificial neural networks (ANN), was constructed. Data on nine water variables from 2007 to 2008 were used to develop models. The hybrid method achieved more accurate prediction compared with PCR and ANN. The R² values were 0.762, 0.815 and 0.927 for PCR, ANN and the hybrid method, respectively. In a case application, the predictions of the hybrid method were found to been consistent with the observed values from January to June in 2009, while the predictions of PCR and ANN did not fit well for sample site 4 and 5.

Abstract: Base on estimate the amount of nitrogen (N) added to the agroecosystem by human activities, and analyze changes in the environment influence of excess N and fertilizer nitrogen use efficiency (FNE) in agricultural fields of the Yangtze River Basin between 1990 and 2000. Excess N is stored in farmland and transferred to water bodies. The excess N stored in farmland was 2.75 Tg N in 1990 and 3.88 Tg N in 2000. The total N transferred to water bodies was 3.45 Tg N in 1990 and 5.07 Tg N in 2000. The FNE decreased by 22.17 % from 1990 to 2000. Changes in the geographic distribution of variational trends of the N budget, N transferred to water bodies, and FNE are more pronounced in the middle and lower reaches of the Yangtze River Basin. We propose effective measures for maximizing the efficiency of N use and reducing the impact of agricultural N on environment in the Yangtze River Basin.

Abstract: This paper focuses on computational fluid dynamics (CFD) simulation of the dynamic exploited influence of wind field in the open pit quarry. We have picked up 3 normal exploitation parameters, e.g. the exploited depth z, the type of small hills and the measured velocity u₁, 7 simulated experiments have been done by software Fluent as well. In our experiments, the features of velocity field around the mine are shown, with the effects of open pit quarry, so as to analyze the changes of wind speed when it gets through this mine. To be exact, it will be possible to deduce there is negative correlation between the velocity decreased gratitude and the exploited depth. Besides, with the shelter effect of a small hill, the wind speed tends to slow down near this hill, and turn back to rise until the flow leaves the hill far away. The velocity decreasing has positive correlation with the measured velocity u₁, and the reverse flow is more likely to appear with higher u₁.

Abstract: Psychological adaptation towards environmental ergonomic is important to encourage better usage of outdoor space. Green space is a significant aspect as it is beneficial for the community. Outdoor spaces are supposedly an essential component of urban recreation space that provides opportunities for recreational activities. Human responses to the outdoor environment and actual thermal sensation experienced by individuals are important to determine the people’s level of understanding of the condition. This paper explores people’s perception about the microclimate condition in hot and humid climate. The responses of the respondents are correlated with the measurement of the microclimate condition. The microclimate conditions of the urban recreational area are measured to get the actual sensation of thermal experience of the people. The results confirmed the existence of adaptive thermal comfort amongst the respondents where they perceived better microclimatic conditions compared to what were measured.

Abstract: A set of simulation device was built on the head end of tunnel. Experiments on the thermal environment of the tunnel were conducted by adjusting the parameters of the supply air and the supply air distance. Experimental results are presented at different layout of the ventilation duct. The range of supply air is at 0.02 cubic meters per second to 0.06 cubic meters per second and the supply air distance is at 0.7m to 3.5m. Experiment results show that the tunnel temperature may be regulated blow 28°C only using ventilation for the virgin rock temperature near 45°C. Experiment result and theory prediction both is basically consistent. Experiment results have provided a direction for the select of cooling design and strategy.

Abstract: This study was conducted to evaluate the effects of roof thermal insulation on the indoor thermal environment of an existing enclosed giant freshwater prawn hatchery in relation to human thermal comfort and the thermal requirement for optimal larval growth. A typical medium scaled enclosed hatchery in Ipoh, Malaysia was chosen for this study. Thermal performances of five thermal insulation materials installed on the roof of the building were studied using Integrated Environmental Solutions (IES) Virtual Environment software. Results showed no significant differences for indoor air temperatures reduction among the insulation materials. However, the installation of roof insulation gave a cooler indoor thermal environment and provided a suitable water temperature/ improved water thermal condition for the prawn larviculture. The study also suggested the aluminium foil was the best insulation for the partially transparent roof of the building.

Abstract: Suspended sediment (SS) is one of the important parameters quantifying the degree of water pollution. In order to explore the spatiotemporal variation of the SS in Le’an river catchment, an important sub-catchment of Poyang lake basin, a total of 17 sampling points at rivers were selected for observations. Results show that, the concentration of SS is quite different across the catchment. The average concentration of SS in the upstream of the catchment with forest as the dominant land use, is 6.92mg/L, while the concentration in the downstream with a certain percentage of arable land is 14.39mg/L. The SS concentration shows an increasing trend from the upstream to the downstream, in correlation with the change of land uses. Also there exists a considerable deviation of the SS concentration in different seasons. The concentration in summer is relatively high, while lower in other seasons, with a likely relationship to rainfall events.

Abstract: Permanganate index (CODMn) is one of the important indicators used to evaluate the pollution level of the water, the current national standard method is the redox titration. The research of measuring permanganate index using adopting the spectrophotometry by using the strong oxidation characteristics of the potassium permanganate. Through research, the selected optimum analysis parameters: detection wavelength 525 nm，potassium permanganate concentration 0.0025 mol/L , sulfuric acid dosage 5.00 mL, heating temperature 90 °C and heating time 30 min. Compared with the national standard method, this method would simplify the reaction process, reduce error and guarantee the test accuracy. The evaluation of this test method confirms it has high accuracy and sensitivity, which is also easy to operate and fulfill the online monitoring.

Abstract: This article is based on gold-mine. Analyzing the correlation of heavy metal content between tree rings and soil. Through the distribution of heavy metal content in the trees inverse the process of heavy metal pollution in soil. Discussing the time distribution of heavy metal pollution.