Mathematical Modelling and Experimental Evaluation of Electrostatic Sensor Arrays for the Flow Measurement of Fine Particles in a Square-shaped Pipe

Abstract—Square-shaped pneumatic conveying pipes are used in some industrial processes such as fuel injection systems in coal-fired power plants and circulating fluidized beds. However, little research has been conducted to characterise the gas–solid two-phase flow in a square-shaped pneumatic conveying pipe. This paper presents mathematical modelling and experimental assessment of novel non-restrictive electrostatic sensor arrays for the measurement of pulverised fuel flow in a square-shaped pipe. The sensor arrays consist of twelve pairs of strip-shaped electrodes, which are uniformly embedded in the four flat pipe walls. An analytical mathematical model of the sensor arrays is established and the induced charge and currents of different electrodes due to a point charge are then derived based on the model. Experimental tests were conducted on a 54 mm square-shaped pipe section of a pneumatic conveyor test rig under a range of flow conditions. The fuel velocity profile over the whole cross-section of the pipe is measured. Mathematical modelling and experimental results demonstrate that the proposed non-restrictive electrostatic sensor arrays are capable of characterising the local pulverised fuel flow in a square-shaped pneumatic conveying pipe. Index Terms—electrostatic sensor, square-shaped pipe, mathematical modelling, velocity profile, pulverised fuel

Measurement of the Mass Flow Distribution of Pulverized Coal in Primary Air Pipes Using Electrostatic Sensing Techniques

On-line measurement of pulverized fuel (PF) distribution between primary air pipes on a coal-fired power plant is of great importance to achieve balanced fuel supply to the boiler for increased combustion efficiency and reduced pollutant emissions. An instrumentation system using multiple electrostatic sensing heads are developed and installed on 510 mm bore primary air pipes of a 600 MW coal-fired boiler for the measurement of mass flow distribution of PF. An array of electrostatic electrodes with different axial widths is housed in a sensing head. An electrode with a greater axial width and three narrower electrodes are used to derive the electrostatic signals for the determination of PF mass flow rate and velocity, respectively. The measured PF velocity is used for the calibration of coal mass flow rate. On-plant comparison trials of the developed system were conducted under typical operating conditions. Isokinetic sampling equipment is used to obtain reference data to evaluate the performance of the system. Experimental data demonstrate that the developed system is effective and reliable for the on-line continuous measurement of PF mass flow distribution between the primary air pipes of the same mill

Asynchronous adaptive time step in quantitative cellular automata modeling

BACKGROUND: The behaviors of cells in metazoans are context dependent, thus large-scale multi-cellular modeling is often necessary, for which cellular automata are natural candidates. Two related issues are involved in cellular automata based multi-cellular modeling: how to introduce differential equation based quantitative computing to precisely describe cellular activity, and upon it, how to solve the heavy time consumption issue in simulation. RESULTS: Based on a modified, language based cellular automata system we extended that allows ordinary differential equations in models, we introduce a method implementing asynchronous adaptive time step in simulation that can considerably improve efficiency yet without a significant sacrifice of accuracy. An average speedup rate of 4–5 is achieved in the given example. CONCLUSIONS: Strategies for reducing time consumption in simulation are indispensable for large-scale, quantitative multi-cellular models, because even a small 100 × 100 × 100 tissue slab contains one million cells. Distributed and adaptive time step is a practical solution in cellular automata environment

Multi-agent coalition formation in power transmission planning

Deregulation and restructuring have become unavoidable trends to the power industry recently in order to increase its efficiency, to reduce operation costs, or to provide customers better services. The once centralized system planning and management must be remodeled to reflect the changes in the market environment. We have proposed and developed a multi-agent based system to assist players, such as, owners of power generation stations, owners of transmission lines, and groups of consumers, in the same market to select partners to form coalitions. The system provides users with a cooperation plan and its associated cost allocation plan for the users to support their decision making process. Bilateral Shapley Value (BSV) was selected as the theoretical foundation to develop the system. The multi-agent system was developed by the combination of IDEAS and Tcl/Tk.published_or_final_versio

Effects of La3+ on ATPase activities of plasma membrane vesicles isolated from Casuarina equisetifolia seedlings under acid rain stress

The effects of La3+ on the growth and the ATPases activities of plasma membrane(PM) vesicles isolated from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5) stress were studied. The results show that the height, length of roots, fresh weight and PM H+-ATPase activites of Casuarina equisetifolia seedlings increase by the treatments of soaking seeds in LaCl3 solutions with lower concentrations, and those can reach their peak values by treating with 200 mg . L-1 La3+. However, in comparison with the CK, those are inhibited by the higher La3+ concentrations; PM Ca2+-ATPase activity is inhibited with the treatments of La3+. The results also reveal that the H+-ATPase activity and the growth of cell enlarge have a remarkable positive correlation, and La3+ activating H+-ATPase can facilitate plant growth. La3+ also can alleviate cytosolic acidification of plant under acid rain stress and indirectly maintain the stability of intracellular environment. In order to resistant to acid rain and accelerate the growth of Casuarina equisetifolia, the suitable range of La3+ concentrations to soak seeds for 8 h is 50 similar to 200 mg . L-1

Spatiotemporal heterogeneity of plankton communities in Lake Donghu, China, as revealed by PCR-denaturing gradient gel electrophoresis and its relation to biotic and abiotic factors

The 16S and 18S rRNA genes of planktonic organisms derived from five stations with nutrient gradients in Lake Donghu, China, were studied by PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting, and the relationships between the genetic diversity of the plankton community and biotic/abiotic factors are discussed. The concentrations of total nitrogen (TN), total phosphorus (TP), NH4-N and As were found to be significantly related (P < 0.05) to morphological composition of the plankton community. Both chemical and morphological analyses suggested that temporal heterogeneity was comparatively higher than spatial heterogeneity in Lake Donghu. Although the morphological composition was not identical to the DGGE fingerprints in characterizing habitat similarity, the two strongest eutrophic stations (I and II) were always initially grouped into one cluster. Canonical correspondence analysis suggested that the factors strongly correlated with the first two ordination axes were seasonally different. The concentrations of TN and TP and the densities of rotifers and crustaceans were generally the main factors related to the DGGE patterns of the plankton communities. The study suggested that genetic diversity as depicted by metagenomic techniques (such as PCR-DGGE fingerprinting) is a promising tool for ecological study of plankton communities and that such techniques are likely to play an increasingly important role in assessing the environmental conditions of aquatic habitats.The 16S and 18S rRNA genes of planktonic organisms derived from five stations with nutrient gradients in Lake Donghu, China, were studied by PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting, and the relationships between the genetic diversity of the plankton community and biotic/abiotic factors are discussed. The concentrations of total nitrogen (TN), total phosphorus (TP), NH4-N and As were found to be significantly related (P < 0.05) to morphological composition of the plankton community. Both chemical and morphological analyses suggested that temporal heterogeneity was comparatively higher than spatial heterogeneity in Lake Donghu. Although the morphological composition was not identical to the DGGE fingerprints in characterizing habitat similarity, the two strongest eutrophic stations (I and II) were always initially grouped into one cluster. Canonical correspondence analysis suggested that the factors strongly correlated with the first two ordination axes were seasonally different. The concentrations of TN and TP and the densities of rotifers and crustaceans were generally the main factors related to the DGGE patterns of the plankton communities. The study suggested that genetic diversity as depicted by metagenomic techniques (such as PCR-DGGE fingerprinting) is a promising tool for ecological study of plankton communities and that such techniques are likely to play an increasingly important role in assessing the environmental conditions of aquatic habitats

Down-expression of inducible nitric oxide synthase (iNOS) and endothelial (Enos) proteins and mRNA iNOS in bronchiectasis in vivo

published_or_final_versio

Vertical distribution of acid-volatile sulfide and simultaneously extracted metals in mangrove sediments from the Jiulong River Estuary, Fujian, China

Background. Acid-volatile sulfide (AVS) is operationally defined as sulfides in sediment, which are soluble in cold acid, and is reported as the most active part of the total sulfur in aquatic sediments. It is a key partitioning phase controlling the activities of divalent cationic heavy metals in sediment. Methods. In order to examine this in mangrove environments, six sites were selected along the Jiulong River Estuary in Fujian, China, which had previously been reported to be polluted by heavy metals. Sediments were sampled from 0-60 cm depth at each site, and the spatial distribution of AVS and SEM (simultaneously extracted metals: copper, cadmium, zinc, and lead) were determined. Results and Discussion. The results indicate that the AVS concentrations had a spatial variation, ranging from 0.24 to 16.10 mu mol g(-1) sediment dry weight. The AVS concentration in the surface layer is lower than that of the deeper sediment, with peak values in the 15-30 cm horizon. There was no correlation between the AVS value and organic matter content or total dissolved salts, but a significant positive correlation of AVS with surface sediment (0-5 cm) moisture content was found. This indicates that water logged sediments tend to have a high AVS value. The amount of SEM was within the range of 0.33-2.80 mu mol g(-1) sediment dry weight and decreased with sediment depth. Conclusions. There was a marked variation in AVS and SEM among different sites studied. AVS concentrations were generally lower in the surface sediments, while SEM concentrations slightly decreased with the depth. Higher concentrations of SEM found in the upper layers of the sediments confirm the earlier suggestions that this study area may suffer from increasing heavy metal pollution. Recommendations and Perspectives. When monitoring environmental impacts by using AVS, the micro and large-scale spatial variation as well as vertical distribution need to be estimated to avoid misleading results. Both AVS and SEM concentrations in different sediment layers should be taken into account in assessing the potential impact of heavy metals on the biotic environment