Advanced Materials Research Vols. 347-353

Abstract: Subsurface drip irrigation (SDI) that has a wide application prospect is one of the high efficiency water-saving irrigation techniques. Research on regulation of soil-water dynamics in irrigation design parameters of SDI has important points in improving its irrigation design and guiding its practical function. In this study, soil wetting patterns were investigated in laboratory experiments which were operated at three different dripper discharges (0.76, 1.15 and 1.25 l h-1) and two different irrigation amounts (4.6 and 9.2 l). The results showed that, (1) with the increase of dripper discharges from 0.76 l h-1 to 1.25 l h-1, water content around the emitter are increasing from 0.225 cm3 cm-3 to 0.300 cm3 cm-3, (2) increasing the dripper discharge and irrigation amount increased the size of the wetted zone, (3) upward distance of the wetting front is less than downward distance and horizontal distance of the wetting front presents symmetry distribution at the same the dripper discharges and irrigation amount, (4) with the increase of irrigation amounts from 4.6 l to 9.2 l, water contents of the vertical and horizontal direction are increasing 10% to 20%.

Abstract: The research of this paper is on the free sloshing mode of liquid tank with baffles. The liquid tanks FEM model is made in ANSYS, and some investigation is done on its sloshing mode and the shape of free surface, under different filling ratio conditions. After comparing the tanks without baffles with the one with baffles, it is found that the sloshing mode, basic frequencies and free surface shape are all affected by baffles. And the same free surface shape appears in different liquid tanks, but in different mode. It also can be concluded that there are close mode frequencies in symmetrical tanks.

Abstract: Aiming at the problem of traditional iterative way to achieve method of multi-step prediction, new method of multi-step prediction based on parallel Support Vector Regression (SVR) was proposed. To begin with the time delay of time series will be calculated in this method, resample the time series according to the interval of time delay. What’s more the time series will be classified into several sets of data, and it sets up SVR model for the sets of each. Finally, the parallel prediction of each set is composed to get multi-step prediction result. This method not only eliminates the accumulated error, improves the accuracy of prediction, but also saves the computation time.

Abstract: We conducted two campaigns to study total mercury (THg) and methyl mercury (MeHg) in water bodies of Xiaolangdi reservoir, which were constructed in 2001 and drained for desilification in early June every year. The first campaign was conducted in May 2010 and 7 sampling sites were selected from upstream to the dam. The second campaign was conducted in Nov. 2010 and 3 sampling sites were selected in Nov.2010. Our results showed that the average THg(30.5ng/L) concentration of water bodies in main channel of xiaolangdi reservoir was higher that of in tributary (19.3ng/L) and declined from upstream to downstream water body. Drainage of reservoir could decline mercury in water and water residence time was an important variable affecting mercury accumulation. The MeHg concentration had the same trend compared to THg from upstream to downstream water bodies. Mingzhudao, luoyu and dam water bodies were 0.045ng/L, 0.039ng/L and 0.037ng/L water bodies, respectively.

Abstract: The liquefaction of wheat straws in sub-critical water to obtain bio-oil was investigated in this paper. We observed that the reaction temperature (300-374 °C) and reaction time (1-15 min) played important roles in the yield of bio-oil and found the optimal reaction conditions (340 °C, 5 min). The bio-oil was analyzed by elemental analysis, the Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). Results indicated that the heating value of bio-oil product was 32-38 MJ/kg, higher than that of the bio-oil obtained from microalgae, and the product was composed of ketones, phenol and its derivatives, aromatics and small amount of aldehydes and ethers.

Abstract: In this work, some combustion experiments on PVC, rice hull, and their mixture were carried out in a fixed-bed reactor to obtain the influence of temperature, oxygen concentrations on the emission of NO. The NO emission during the co-combustion of PVC and rice hull had the same tendency as the rice hull combustion had, and it increased slowly along with the rising of temperature and oxygen concentration. The experiment results also indicate the co-combustion leaded to lower NO concentration, and it was considered that some reducing substances existed in co-combustion process leaded to a certain reduction in NO emission. The FactSage and Chemkin simulation results have a good agreement with the experiment data, and reveal that the main production reactions are: NO2+ONO+O2, NO2+HNO+OH. In addition, large amounts of volatile released by PVC in co-combustion process formed strong reducing atmospheres, which acted the major roles in the NO reduction.

Abstract: This paper focuses on investigating the flow structures in a multi-hole swirl burner. Using the Particle Image Velocimetry(PIV) technique, the experiment measured the velocity distributions of the swirling flame in a muti-hole burner. The experiments show that there is a central recirculation zone (CRZ) in the middle of the flow field, and two counter-rotating vortices exist along the centerline symmetrically. With fuel jet increase: the width of recirculating zone and axial mean velocity peaks changes little; length of recirculation zone and the biggest reverse flow velocity increases; the expansion angle of swirling jet increase at first, and then changes little; axial non-uniform coefficient of outlet reduces at first, and then increases. With airflow velocity increase: axial mean velocity peaks increase; the dimension of recirculating zone and the expansion angle of swirling jet are unchanged; axial non-uniform coefficient of outlet increases.The data from this experiment is helpful for optimization of the swirl burner design, and can be established as benchmarks for the development and validation of swirl combustion numerical simulations.

Abstract: Biomass briquetting technology is one of the key technologies about biomass energy. In this paper we established solid model of biomass plane-die briquetting machine by UG software and imported the model into software-ADAMS/View module to simulate the process and to analyse dynamic characteristic parameters. Under the conditions of the same spindle speed and different roller pressures, we obtained the characteristic curves of the main spindle bearing torque and the motor power. The results of simulation showed that the main spindle beared torque increased along with the increase of the roller pressure so that the needed motor power increased. The maximum simulated motor power is in the start-up stage through which we can get the correction coefficient k compared with the theoretical value. According to the above analysis, we got the dynamic characteristic model of the biomass plane-die briquetting machine which can provide theoretical basis for related equipment design.

Abstract: Pyruvate phosphate dikinase (PPDK) catalyzes the reversible conversion of AMP, phosphoenolpyruvate (PEP) and pyrophosphate (PPi) to ATP, pyruvate and inorganic phosphate (Pi). It is a key enzyme in gluconeogensis and photosynthesis that is responsible for reversing the reaction performed by pyruvate kinase in Embden-Meyerhof-Parnas glycolysis. A cDNA clone for the Dunaliella parva PPDK was isolated by sequencing. Then the 3'-RACE and 5'-cDNA amplification were conducted based on the obtained sequence. The molecular characterization of the PPDK gene was described.The Dunaliella parva PPDK gene cDNA sequence was 3249 bp, which contained 2595 bp coding region and 654 bp 3'-untranslated regions. The deduced amino acid sequence of Dunaliella parva PPDK showed significant homology to the known PPDK from Volvox carteri and Chlamydomonas reinhardtii. This study provided foundation for further research on the function analysis and overexpression of PPDK genes. To our knowledge this is the first reported.

Abstract: A gene encoding a cellobiohydrolase (CBH) was isolated from Aspergillus niger-NL-1 and designated as cbh1. The cbh1 gene contains 1,515 nucleotides with three introns and encodes a 452-amino acid protein with a molecular weight of approximately 60 kDa. The amino acid sequence encoded by cbh1 shows high homology with the sequence of glycoside hydrolase fimily 7. The cellobiohydrolase (cbh1) gene was succussfully expressed in Pichia pastoris KM71H. The recombinant CBHⅠshowed an optimal working condition at 60 °C, pH 4.0 with K_m and V_max toward CMC-Na of 13.81 mM and 0.269 μmol/min, respectively. The enzyme retained more than 80 % of its initial activity after 2 h of incubation at 90 °C and was stable in pH range 1.0～10.0. Because of its moderately stable at high temperature and stability through wide range of pH, this enzyme has potential in various industrial applications.