Applied Mechanics and Materials Vols. 448-453

Abstract: The physical model experiment was carried out to study the effect of velocity ratio of two layers on the turbulence intensity of stratified flow in the typical braided rivers with two symmetrical anabranches. Two velocity ratios were selected, and the distributions of depth-averaged turbulent intensity component in the left anabranch were analyzed. When velocity ratio became smaller, the turbulent intensity increased and peak turbulent intensity zone transferred from the left area of centerline to the right area of centerline at the section before the bend apex of the anabranch. In the outlet section of the anabranch, turbulent intensity increased at the inner bank. The distributions of lateral-averaged turbulence intensity components in the vertical sections of left anabranch were also analyzed. Turbulence intensity component in the interface of hot and cold water was both high in two velocity ratios. As water flowed downstream, the difference of turbulent intensity component in the vertical direction decreased obviously.

Abstract: NO reduction by iron was conducted in a one-dimensional ceramic tubular reactor at 300 - 1100 °C with simulated flue gas of 0.05% NO in N₂ base. The evolution of metallic iron was investigated by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) methods. The effect of reducing gases including CO and CH₄ was analyzed on the redox of iron. Results showed that metallic iron was oxidized to its oxides after the reaction with NO. In N₂ atmosphere, Fe₃O₄ was the major iron oxide at 550 °C and Fe₂O₃ was the major iron oxide at 1100 °C. SEM image of the iron sample surface showed that the iron surface was smooth and dense after the iron reduced NO at 550 °C, however, the iron surface became porous after the iron reduced NO at 1100 °C. Reducing gas CO could reduce iron oxides to metallic iron. XRD result showed that a little FeO was found but metallic iron was still the dominant component of the iron sample after the reaction with NO in CO atmosphere. CO was not effective to maintain a durable NO reduction efficiency in simulated flue gas atmosphere while CH₄ was very effective. XRD result of the iron sample after the 100 hours durable test at 1050°C when 1.17% CH₄ was added into the simulated flue gas showed that the iron was not fully oxidized during the durable reaction.

Abstract: A series of biological drying and odor emissions experiments of municipal solid waste (MSW) was made by using independently developed biological drying device. . The results show that: Ventilation increasing contributes to the loss of water and reduction of H₂S emission, as well as conducive to biochemical reactions. Additives of T2 and T4 can significantly reduce the emission of H₂S and additives of T2 and T3 can significantly reduce the emission of NH₃, thus, T2 can preferably chose as biodrying deodorant. Turning process has a certain impact on the biodrying product moisture content, moisture content decreases with the increase of turning times, the moisture of final biodrying product reached 25% when turning twice, reached 22.5% when turning 3 times and, reached 19.1% when turning 4 times. Thus, increase the turning times can significantly reduce moisture content.

Abstract: For the sake of evaluating the content of mineral oil and in water, and further more we can judge water quality pollution, we finally develop an infrared spectrometer based on STM32 which is on the basis of infrared spectrophotometry. The instrument realizes calculating the absorbance and concentration automatically with the help of high-precision pyroelectric infrared sensor and signal processing circuit. Besides it combines with built-in A/D converter and USB data transmission module, it can draw the standard curve on the host computer. Experiment results show that the instrument is accuracy enough and simple enough to use.

Abstract: Efficient nitrite adsorbent materials made from corncobs through physical and chemical modification were used to adsorb nutrite in seawater. In this experiment, the effect of time and modification on corncobs adsorption capacity was studied. It shows that the removal ratio for nutrite presented an increasing tendency over time and reached the highest after 270 minutes, the removal ratio of modified corncobs reached 52.1%, which improved 10% compared with unmodified corncobs. Besides, through contrastive experiment with some other nitrite adsorbent materials, modified corncobs are proved to have the highest removal ratio for nutrite.

Abstract: In this study, water samples were collected randomly from water system of Beijing urban area and analysed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) method to determine the contents of harmful heavy metals (Hg, Cd, Zn, Cu, Ni, Cr, Sb, As and Pb). The concentrations of detected heavy metals were found between detection limit of the instrument to 387.196 mg/L. Among them, one sample gave a very high concentration of copper element. In order to get rid of this copper ion away, a chelating type fiber was used to treat the water sample. After treatment with chelating fiber, the concentration of copper was lowered to <10^-5mg/L.

Abstract: In this paper, nanocopper oxide is prepared by complexing-precipitate, and the influence of different process parameters on the removal of H₂S performance are studied, and make a comparison for two other methods. The results indicate that different complexing agent, the molar ratio of Cu²⁺/OH^- and calcination temperature, etc., effect the desulfurization activity of nanocopper oxide. nanocopper prepared under optimum conditions (the complexing agent is ammonia, the molar ratio of Cu²⁺/OH^- is 1:3.0, calcination temperature is 400 °C) exhibits best desulfurization activity with a H₂S breakthrough time of 235 min, this is much longer than that prepared by hydrothermal method and sol-gel method with breakthrough time of H₂S only 20 min and 50 min, respectively; XRD analysis shows that the big grain size of nanocopper oxide and low purity are not in favor of H₂S adsorption at room temperature.

Abstract: An integrated two-phase anaerobic reactor was designed to treat domestic sewage, and the corresponding start-up process was investigated.In this investigation, the volumetric loading rate ( VLR) of the system was raised by basically maintaining the influent COD ( Chemical Oxygen Demand) concentration and gradually decreasing the hydraulic retention time (HRT) at 35°C，and the start-up process was completed only in the 36 days. When the Influent pH was kept in the range of 7.39 ~ 7.67，the acidogenic phase and the methanogenic phaseof integrated two-phase anaerobic reactor were separated only by using the kinetic method. After completing this process, the reactor operated well with VLR at 1.31 kg / ( m3·d) and HRT at about 7h, and a COD removal of more than 80%,a SS removal of about 90% and a gas production rate of about 0.31L/h were respectively achieved.

Abstract: Parts of emission from the aircraft engine are doing harm to the environment. The greenhouse gas emission (CO₂ equivalent) per passenger per thousand kilometers is used to measure the emissions in this work. And a new estimation method of emissions for aircraft conceptual design was proposed, based on the ICAO aircraft engine emissions databank and the response surface fitting methods. Because the amounts of greenhouse effects of various pollutant gases rely on altitudes, the estimation accuracy of emission was improved by refining the flight dynamics models in various stages of mission profile. The impacts of the wing configuration on greenhouse effect were discussed, after verifying the accuracy of this proposed method. The results indicate that the greenhouse gas emissions could be reduced by appropriately increasing wing sweep and aspect ratio.

Abstract: Aiming at the fact that the low concentration sewage in small cities, this paper presents Two-phase Anaerobic Baffled Reactor (TAABR) for living wastewater treatment, importantly, it designs and researches Two-phase Anaerobic Baffled Reactor and its advantages, designs a trial project according to the characteristics of the reactor equip. The experiment uses the method that by shortening HRT to raise the load to start and analyses the operating results during startup as follows: 1. 53 days later anaerobic reactor start-up successes.2. When the load is 0.5kgCOD/m³.d, the removal rate of COD is more than 80%. 3. PH value is not the main limiting factors during start up in the reactor and there is basically no danger of excessive acidification.