钢筋混凝土梯形条缝滤水管的成井试验

一、问题的提出 我国六十年代以来,农用浅机井滤水管,绝大部分使用多孔混凝土滤水管。这种滤水管在北方发展井灌中起过相当大的作用。但由于孔隙通道迂回曲折,大小不一,不仅其进水阻力较大,而且还易造成机械堵塞。因此更换一种开孔率大、阻力小、效率高、出水量大、不堵塞、寿命长的新型滤水管,是当前机井更新工作中急需解决的关键问题,我们参考国外滤水管较先进的约翰逊缠丝骨架过滤器。

过滤离心机的新型滤网──扁条滤网

本文分析了螺旋卸料过滤离心机采用衬网时，固定滤饼对过滤的不利影响及采用板状、条状滤网的不足，提出以扁条滤网来取代，彻底摒弃固定滤饼，以提高过滤速度，缩小滤网缝隙而扩大过滤离心机的应用范围。

Leaching of vanadium and chromium from converter vanadium slag intensified with surface wettability

Technology intensified with surface wettability was introduced to leach vanadium and chromium from converter vanadium slag without roasting. Parameters affecting the leaching efficiency of vanadium and chromium were investigated： sulfuric acid concentration, MnOz-to-slag mass ratio, liquid-to-solid ratio, leaching time, leaching temperature, and sodium dodecyl sulfate （SDS）-to-slag mass ratio. The leaching efficiencies of vanadium and chromium were 33.46 % and 20.02 % higher in the presence of MnO2 and SDS, respectively, compared to the control. The leaching efficiencies of vanadium and chromium were 68.93 % and 30.74 %, respectively, under the optimum conditions： sulfuric acid concentration 40 wt%, MnOz-to-slag mass ratio 10.0 wt%, liquid-to-solid ratio 5：1 mL/g; 12 h; 90 ~C; and SDS-to-slag mass ratio 0.25 wt%. The analysis of the reaction mechanism in the leaching process indicates that MnO2 combined with protons （H＋） could oxidize low-valent vanadium and chromium; SDS could change the chemical behavior and decrease the surface tension of the aqueous solution to favor MnO2 oxidization.

Methanethiol Removal from Biogas by Biological Conversion in an Anaerobic Biotrickling Filter

In this study, methanethiol（MT）-degradation bacteria were cultivated by using MT, methanol and trimethylamine as carbon sources under anaerobic conditions. It was found that the batch bacteria used MT and metha- nol as carbon sources grew faster than those used trimethylamine. The enriched bacteria used MT and methanol as the carbon sources were respectively inoculated in different biotrickling filters. The biological conversion performance ot MT under anaerobic conditions was investigated in biotrickling filters. The results showed that the performance of the biotrickling filter inoculated with the bacteria enriched using MT was better than that inoculated with the bacteria en- riched using methanol. When the inlet concentration of MT was 0.005vo1% （50 ppm）, the empty bed residence time was 50 s, pH value was 8.0, and the flow rate of the nutrient solution was 10 L/h, the removal efficiency of MT reached 95.3%. Adding methanol stimulated the growth of the biomass and the degradation of MT, but caused that some bacteria only degrading methanol outcompeted the bacteria only degrading MT. The concentration of sodium bicarbonate in the nutrient solution needed to be controlled lower than 30 g/L, otherwise, it would be harmful to the degradation of MT.

A New Attempt of Using Crushed Plastic Solid Wastes in Water Filtration

The aim of this new study is to investigate the ability of using crushed plastic solid wastes in water filtration by using a pilot plant. Two sets of filters were used. The first set represents mono media filters. The first filter is a sand media with effective size of 0.65 mm and the others three are plastic media with different grain sizes. The second set represents dual media filters with different depths, the filters were made to operate with the same effective size （0.6-1.0 mm）. These filters were subjected to the same operating conditions of filtration rates and infiuent turbidity. The filters were operated at rates of 5, 7.5, 10, and 12.5 m/h in order to find the optimum filtration velocity with influent turbidity ranged between 7 and l0 NTU （nephelometric turbidity unit）. The results indicated that the single plastic filters and the dual filters produced water of the same high quality as the sand filter. Plastic filters were slower in the development of head losses by about of 8%-78% less and they have longer running time than the sand filter, while the dual filters were slower in the development of head losses by about of 14%-16% and they have longer running time by about of 12%-40% than the sand filter.

Target Region Location Based on Texture Analysis and Active Contour Model

Traditional texture region location methods with Gabor features are often limited in the selection of Gabor filters and fail to deal with the target which contains both texture and non-texture parts.Thus,to solve this problem,a two-step new model was proposed.In the first step,the original features extracted by Gabor filters are applied to training a self-organizing map(SOM) neural network and a novel merging scheme is presented to achieve the clustering.A back propagation(BP) network is used as a classifier to locate the target region approximately.In the second step,Chan-Vese active contour model is applied to detecting the boundary of the target region accurately and morphological processing is used to create a connected domain whose convex hull can cover the target region.In the experiments,the proposed method is demonstrated accurate and robust in localizing target on texture database and practical barcode location system as well.

Concentration of Vinasse Using Membrane Filtration Processes

The application of single nanofiltration （NF） and sequential filtration of microfiltration （MF） and NF for the concentration of vinasse were studied. Filtration experiments were performed at 60 ℃, 500 rpm and different transmembrane pressures using four commercial membranes： MF, PVDF 0.2 μm; NF, PES 300, 500 and 1000 Da. The process effectiveness was evaluated through the permeate flux and the total solids （TS） concentration in the retentate. Because the retention of TS and permeate fluxes were very similar for MF, PVDF-0.2 membrane at 0.10 MPa was selected because of its lower power consumption. The best conditions tested for NF were the following： PES-1000 at 3.50 MPa with a flux of 183.2 kg/m^2 h at a volume reduction factor （VRF） of 2, under which 68% of solids were retained. For the MF ＋ NF, a PES-1000 at 3.50 MPa was selected because a higher permeate flux was achieved at a VRF of 4, and PES-500 at 3.50 MPa because a higher retention of TS was achieved compared to the other experiments. A single NF resulted in a retentate concentration that was almost twice as high as the hybrid MF and NF process, allowing reduced costs in its transportation from distilleries to distant areas.

Pilot Project on in Situ Aerobisation of Old Landfills： Results from Konstanz Dorfweiher Landfill

A new in situ treatment technique was being utilized on a part of the Dorfweiher landfill in Konstanz, Germany to reduce the aftercare period. From 2010 to 2012, the landfill was aerated intermittently with low pressure. Outgoing air was treated passively in an open biofilter which covers the landfill surface. The landfill was aerated by means of 80 air injection wells arranged area-wide in a 10 m grid. An elaborate measuring process and technological controls are being utilized in the pilot scheme. The data collected offer interesting insights about the processes during aeration, allowing optimization of the aeration strategy depending on changes of the conditions in the landfill. During the three-year aeration phase, conditions have changed inside the landfill section in various ways. In numerous zones of the landfill body, the aeration caused aerobic conditions with a decline of methane production. Accelerated settlings are measured up to 11%. The effects of the aerobic stabilization on the landfill are evaluated in a two-year monitoring phase started in 2013.

Operating Conditions Optimization on Indonesian ＂Batik＂ Dyes Wastewater Treatment by Fenton Oxidation and Separation Using Ultrafiltration Membrane

Broadly speaking, this study aims to develop ＂batik＂ dyes wastewater treatment technologies by hybrid process that combines Fenton oxidation and separation using ultrafiltration membranes. Specifically, the purpose of this study was to determine the effect of membrane characteristics, feed solution pH, operating pressure of ＂Dead-end＂ membrane reactor, and the frequency of membranes which uses on the percentage of COD reduction in ＂batik＂ wastewater. In this study, the filtrate from wastewater pre-treatment with Fenton oxidation, both without and with addition of activated carbon, is passed to the ultrafiltration （UF） separation system. Fenton oxidation process was carried out at optimum conditions, i.e. at pH 3, temperature 50 ℃, and the addition FeSO4·7H2O and H2O2 at 747-830 mg/L and 1,168-1,460 mg/L, respectively. The optimum reduction percentage of COD can be achieved when the membranes used for separation has a pore size of 0.01 to 0.015 lam, feed solution pH 2, operating pressure 1 atm and frequency of membranes uses I x. To determine the fouling potential on ultrafiltration membranes that are used, flux measurements were performed 3 times for each membrane. These stages can see that the flux decline reached 22.5% when the effluent filtered directly to the membrane; 17.3% when performed pre-treatment prior to separation processes using membranes and 10% when combined pre-treatment process, use of activated carbon and the separation using ultrafiltration membranes.

滤饼自行脱落的肩形过滤片

该扇形过滤片是由金属框架及柔性橡胶滤条组成变腔结构。在过滤区域和滤干区域,橡胶滤条因真空吸力变形使由滤条构成的腔体空间紧缩;在卸料区域,橡胶滤条依靠自身的弹力恢复变形使由滤条构成的腔体空间鼓胀。这种腔体的紧缩与鼓胀称之为变腔,这种变腔结构使滤饼自行脱落。

Numerical studies towards practical large-eddy simulation

Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.

The construction of generalized B-spline low-pass filters related to possibility density

Starting from piecewise constant functions, a novel family of generalized symmetric B-splines, with realizable ideal low-pass filters, are constructed. The first order generalized B-spline low-pass filter is closely related to functions analytic in a neighborhood of the unit disc and the generalized sinc functions. The properties of this kind of low-pass filters are investigated. The behavior of the generalized B-spline low-pass filter related to normalized Gaussian distribution is considered.

The structural basis for glycerol permeation by human AQP7

Human glycerol channel aquaporin 7(AQP7)conducts glycerol release from adipocyte and enters the cells in pancreatic islets,muscles,and kidney tubules,and thus regulates glycerol metabolism in those tissues.Compared with other human aquaglyceroporins,AQP7 shows a less conserved‘‘NPA”motif in the center cavity and a pair of aromatic residues at Ar/R selectivity filter.To understand the structural basis for the glycerol conductance,we crystallized the human AQP7 and determined the structure at 3.7Å.A substrate binding pocket was found near the Ar/R filter where a glycerol molecule is bound and stabilized by R229.Glycerol uptake assay on human AQP7 as well as AQP3 and AQP10 demonstrated strong glycerol transportation activities at the physiological condition.The human AQP7 structure,in combination with the molecular dynamics simulation thereon,reveals a fully closed conformation with its permeation pathway strictly confined by the Ar/R filter at the exoplasmic side and the gate at the cytoplasmic side,and the binding of glycerol at the Ar/R filter plays a critical role in controlling the glycerol flux by driving the dislocation of the residues at narrowest parts of glycerol pathway in AQP7.