In the framework of a research project entitled ??BRISA??BReaking waves and Induced SAnd transport??, a methodology was devised to characterize the waves joining together in-situ measurements and numerical wave propagation models. With this goal in mind, a number of in-situ measurements were made, for selected positions in front of Praia de Faro (South Portugal), during four days (25th to 28th March, 2009) by using different types of equipments (e.g., resistive wave gauges, pressure sensors, currentmeters and a new prototype pore pressure sensor using optical fibre). Wave records were obtained simultaneously offshore (at a water depth of 11.7?m below mean sea level, MSL) and at the surf and swash zones. The data processing and analysis were made by applying classical time domain techniques. Numerical simulations of the wave propagation between offshore and inshore for the measurement period were performed with two numerical models, a 1D model based on linear theory and a nonlinear Boussinesq-type model, COULWAVE, both forced by the measured offshore wave conditions of 27th March 2009. Comparisons between numerical results and field data for the pressure sensors placed in the surf and swash zones were made and discussed. This approach enables to evaluate the performance of those models to simulate those specific conditions, but also to validate the models by gaining confidence on their use in other conditions. 相似文献
The concentrations of fine particles and selected gas pollutants in the flue gas entering the stack were measured under several common operation modes in an operating coal power plant producing electricity. Particle size distributions in a diameter range from 10 nm to 20 μm were measured by a scanning mobility particle sizer (SMPS), and the flue gas temperature and concentrations of CO2 and SO2 were monitored by a continuous emission monitoring system (CEMS). During the test campaign, five plant operating modes were studied: soot blowing, bypass of flue-gas desulfurization (FGD), reheat burner operating at 0% (turned off), 27%, and 42% (normal condition) of its full capacity. For wet and dry aerosols, the measured mode sizes were both around 40 nm, but remarkable differences were observed in the number concentrations (#/cm3, count per square centimeter). A prototype photoionizer enhanced electrostatic precipitator (ESP) showed improved removal efficiency of wet particles at voltages above +11.0 kV. Soot blowing and FGD bypass both increased the total particle number concentration in the flue gas. The temperature was slightly increased by the FGD bypass mode and varied significantly as the rating of reheat burner changed. The variations of CO2 and SO2 emissions showed correlations with the trend of total particle number concentration possibly due to the transitions between gas and particle phases. The results are useful in developing coal-fired power plant operation strategies to control fine particle emissions and developing amine-based CO2 capture technologies without operating and environmental concerns associated with volatile amine emissions.
Implications: The measurement of the fine particle size distributions in the exhaust gas under several common operating conditions of a coal-fired power plant revealed different response relations between aerosol number concentration and the operating condition. A photo-ionizer enhanced ESP was demonstrated to capture fine particles with higher efficiency compared to conventional ESPs, and the removal efficiency increased with the applied voltage. The characteristic information of aerosols and main gaseous pollutants in the exhaust gas is extremely important for developing and deploying CO2 scrubbers, whose amine emissions and operating effectiveness depends greatly on the upstream concentrations of fine particles, SO2, from the power plant. 相似文献
For development of an indirect competitive enzyme-linked immunosorbent assay (ELISA) for the nitrile herbicide bromoxynil, the polyclonal antibodies raised against 2,6-dibromo-4-cyano-phenoxyacetic acid (hapten) conjugated to bovine serum albumin (BSA) by the N-hydroxysuccinimide-activated ester method. Antiserum with a sufficiently high titer to provide the determinations of targeted compounds was obtained only 77 days after the primary immunization. Antiserum A2 was applied to the residual analysis of some water samples, under optimized ELISA condition, the quantitative working range was from 10 to 500 ppb with a limit of detection of 5 ppb. Cross-reactivity to structurally similar agrochemicals and related chemicals was determined. The antiserum showed little cross-reactivity with 2,6-dibromophenol and bromoxynil octanoate ester which have a dibromophenol group as common structure, but showed no cross-reactivity with other herbicides. Each water sample (river water, tap water, purified water, and bottled water) had a matrix effect and was investigated by adding Tween20 in the assay buffer. These four kinds of water samples were fortified with bromoxynil at several concentration levels and were directly analyzed with only dilution with an equal volume of antiserum solution, the mean recovery was 102.3%, and the mean coefficient of variation was 5.96%. The proposed ELISA turned out to be a powerful tool for monitoring of residual bromoxynil in water samples at trace level. 相似文献
This work was to give a comprehensive estimation for the chemical compositions contributable to COD of the produced water treatment system. For this purpose, the wastewater samples were collected from an onshore wastewater treatment plant. The chemical compositions of the wastewater were investigated, and the COD contributed by each component was estimated. The results showed that the COD levels of O&G and SS presented decreasing trends during the whole process and achieved total removal percentages of 95.1% and 62.3%, respectively. The final COD of organic acids and low-molecular-weight carbonyl compounds were respectively lowered to nearly 64% and 35% of their initial levels, and no regular trends were found for the COD of these chemicals during the whole treatment process. The COD of inorganic components presented minor variations at all sampling spots. The majority of COD was originated from O&G in raw wastewater. The COD contributed by O&G decreased greatly with continuous treatment and finally was lower than 17% of measured COD. At each sampling spot, the ratios of COD contributed by SS did not exceed 7.6% of measured COD. Other measured chemicals, including organic acids, carbonyl compounds, volatile phenols, reductive anions, metals and TDP were not the main sources of COD during the whole treatment process, and the ratio of COD was below 9% at each sampling spot. Most of the soluble components contributable to residual COD were still unknown after biological treatment, and the COD contributed by these components was greater than 57% of measured COD. 相似文献
In the past decade, the treatment amount of municipal solid waste (MSW) by incineration has increased significantly in Taiwan. By year 2008, approximately 70% of the total MSW generated will be incinerated. The energy content (usually expressed by lower heating value [LHV]) of MSW is an important parameter for the selection of incinerator capacity. In this work, wastes from 55 sampling sites, including villages, towns, cities, and remote islands in the Taiwan area, were sampled and analyzed once a season from April 2002 to March 2003 to determine the waste characteristics. The LHV of MSW in Taiwan was predicted by the multilayer perceptron (MLP) neural networks model using the input parameters of elemental analysis and dry- or wet-base physical compositions. Although all three of the models predicted LHV values rather accurately, the elemental analysis model provided the most accurate prediction of LHV values. Additionally, the wet-base physical composition model was the easiest and most economical. Therefore, the waste treatment operators can choose the more appropriate analysis method considering situations themselves, such as time, equipment, technology, and cost. 相似文献
Driving behavior is largely affected by the risk perception of drivers. On the basis of risk homeostasis theory, we regard that drivers may adjust car movement according to the perceived risks fluctuating around a target level. However, the manner by which risk perception is quantified remains unclear. We propose assumptions on the quantitative indicators of risk perception and identify a suitable quantitative indicator of risk perception in car-following process. Three risk indicators are discussed, i.e. time-to-collision (TTC), time headway (TH), and safety margin (SM). Using homeostatic features as bases, we found that SM more suitably quantifies homeostatic risk perception than TTC or TH does. Data collected from video drive recorders installed in taxis operating in Beijing are used to analyze the target risk level of SM (desired SM, or DSM) of professional drivers during the car-following process. The data collected by Ahn et al. (2004) to verify Newell’s model are converted into DSM data to further analyze the target risk level of general drivers. The DSM histogram of professional drivers shows that the standard deviation of the DSM value is 0.115, with a mean value of 0.862 and a total distribution close to the normal distribution. For a general driver, the mean value of DSM is 0.896, which is higher than that of professional drivers. This research may shed lights on the understanding of driving behavior. 相似文献