Abstract: In order to study the toxic effects of L7 lyophilized powder of extracellular active components (L7-LPEAC) – extracted from the algicidal bacteria L7 – on the aquatic system, Brachydanio rerio were exposed to L7-LPEAC in five different concentrations for a period of 96 hours. The results showed that the 96 h-LC50 is 0.85 g/L, thus the safe concentration is 0.09 g/L. Based on this, four L7-LPEAC concentrations (0.06 g/L, 0.09 g/L, 0.13 g/L, 0.18 g/L) were prepared with the same logarithmic distance, and a 20-day sub-acute toxicity test was carried out. The SOD and ATPase activity in the liver and gill of Brachydanio rerio was measured every 5 days. The results showed that with the increase of L7-LPEAC concentration, the SOD activity decreased significantly (P<0.05), both in liver and gill. Exposed over 10 days, the ATPase activity had little change when the concentration of L7-LPEAC was less than 0.09 g/L; and decreased significantly (P<0.05) when the concentration of L7-LPEAC was above 0.09 g/L.
Abstract: The mathematical and physical model of the liquid propellant spray in straight nozzle was proposed for studying the performance characteristics of the small-scale liquid rocket engine. With the Fluent software, the numerical simulation was carried out. Sauter mean diameter (SMD) of the HAN-based liquid propellant (LP1846) in the engine combustor changing with spray pressure, nozzle diameter and the liquid surface tension were analyzed. The results indicate that: in the spray pressure region of 1.8MPa~3.0MPa, at a fixed spray pressure, the smaller is the nozzle diameter, the smaller is the droplets’ SMD and the relationship between the SMD and the nozzle diameter is approximately linearity; for the same nozzle diameter and spray pressure, the larger is the surface tension, the larger is the liquid droplets’ SMD.
Abstract: The integrated vortex board was made up of many vortex chambers, it was the integration managed in individual vortex tube and its structure was more complicated. It could be regard as one and open ones mouth the system to study. In this paper, basing on the first and second law of thermodynamics, thermodynamics model was set up firstly , which was suitable for the exergy analyses of integrated vortex board energy separation, then the relationships of exergy efficiency and irreversibility were obtained. Combining with the experiment data , the exergy of the integrated vortex board was analyzed, in view of the effect of inlet pressure, cold mass, diameter of outlet orifice, length of hot tube, structure of entrance nozzle on energy separation effect and exergy efficiency. The dimension and operating condition of integrated vortex board could be optimized.
Abstract: The bag filter is a kind of important de-dusting equipment in the power, metallurgy, chemical and building materials industry. Its operation efficiency and running state are two technical indexes of great importance. As for detection of the two indexes, current existing detection methods have various defects. This paper mainly introduces a bag filter on-line monitoring system based on AC charge induction. By using the international advanced AC charge-coupling technology and digital signal processing technology, it can accurately monitor the bag breaking state of filter and put out alarm. In the bag filter on-line monitoring process, the system well solves the technique difficulties of the measuring equipment in such aspects as anti-blocking, wear resistance, low pressure losses, accuracy and reliability, etc. It has the advantages of high measuring accuracy and easy installation and maintenance, therefore, it can bring certain economic benefits and have the prospect of popularization and application.
Abstract: The objective of the study is to focus on the application of the artificial neural network to configure a heat-radiating model for cooling towers within the parameters of fluctuating in air flow or cooling water flow. To achieve the objective, a cooling tower heat balancing equation have been used to instill the correlations between a cooling tower cooling load to the four predefined parameters. Based on the premise established, the parameters of a cooling tower’s air flow and cooling water flow in a modulated process are utilized in an experimental system for collecting relevant operating data. Lastly, the artificial neural network tool derived from the Matlab software is utilized to define the input parameters being – the cooling water temperature, ambient web-bulb temperature, cooling tower air flow, and cooling water flow, with an objective set to instilling a cooling tower model for defining a cooling tower cooling load. In addition, the tested figures are compared to the simulated figures for verifying the cooling tower model. By utilizing the method derived from the model, the mean error of between 0.72 and 2.13% is obtained, with R2 value rated at between 0.97 and 0.99. The experiment findings show a relatively high reliability that can be achieved for configuring a model by using the artificial neural network. With the support of an optimized computation method, the model can be applied as an optimization operating strategy for an air-conditioning system’s cooling water loop.