Homogeneous Acetylation of Cellulose at Relatively High Concentrations in an Ionic Liquid

At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.

Particle characteristics and rheological constitutive relations of high concentration red mud

Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure theology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.

EXPERIMENTAL INVESTIGATIONS ON DIFFUSION CHARACTERISTICS OF HIGH CONCENTRATION JETS IN ENVIRONMENTAL CURRENTS

By means of flow visualization and quantitative measurement, the diffusion pattern and concentration distribution characteristics of high concentration jets vertically discharged into shallow moving waterbody were experimentally investigated in water channel. The interactions between the high concentration jets and environmental flow conditions were analysed, and the formulae of impinging point coordinate and transverse spread angle are gained from data analysis. Experimental results indicate that the jets show complicated flow patterns and diffusion characteristics in near region, which are different from common submerged jets, and spread downstream in the manner of density currents.

Reduction of Cr(Ⅵ) with a relative high concentration using different kinds of zero-valent iron powders: Focusing on effect of carbon content and structure on reducibility

Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.

Calculation of H_2O-NH_3-CO_2 Vapor Liquid Equilibria at High Concentration Conditions

A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

Preparation of High Concentration Polyaluminum Chloride with High Al_c Content by Membrane Distillation

A direct contact membrane distillation（DCMD）process was applied to prepare high concentration polyaluminum chloride（PACl）with high Alc content.The changes in total Al concentration（AlT）and Al species distribution were investigated.The results showed that AlT increased but the flux decreased with operating time during the DCMD process.The Alc content increased from 65%to 81%while the Alb content decreased from 34% to 18%,and the Ala content was almost 1%in the process.2.1 mol·L 1PACl with 81%Alc was successfully prepared by DCMD method.Thus the DCMD is an effective method for preparing high concentration PACl with high Alc content.

Influence of high concentration Zn^(2+) on floatability of sphalerite in acidic system

The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectron spectroscopy.The results indicated that Zn^(2+) was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn^(2+) concentration of 4×10^(-2) mol/L.The zeta potential increased and the contact angle decreased from 84.80°to 36.48°,strongly inhibiting the floatability of sphalerite.When S^(2−) or Cu^(2+) activator was used alone,sphalerite was not activated after Zn^(2+) was adsorbed,and its contact angle did not change significantly.However,by using a combination of S^(2−) and Cu^(2+) activators,its floatability was realized after Zn^(2+) adsorption.This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S^(2-).After this removal,Cu^(2+) was adsorbed on the sphalerite surface to form a Cu_(2)S·S^(0) hydrophobic film.

Effects of High Concentration Glucose on the Expression of NF-κB,Bax and Cytochrome C and Apoptosis of Islet Cells in Mice

The roles of NF-kappaB （NF-κB） expression, Bax activity and cytochrome C （Cyt C） release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were isolated from Kunming mice, were cultured with different concentrations of glucose in DMEM, and divided into the following groups： G1, G2, G3, G4, G5, and G6 groups, corresponding to the glucose concentrations of 5.6, 7.8, 11.1, 16.7, 22.5, and 27.6 mmol/L, respectively. After culture for 120 h, insulin secretion was evaluated by radioimmunoassay, and the NF-rd3 expression was detected by immunocytochemistry. Bax activity and Cyt C release were measured by immunofluorescence, and apoptosis was examined by Hoechst33342 assay. The results showed that in GI, G2 and G3 groups, insulin secretion was enhanced with the increase of glucose concentration, and the NF-κB expression was also increased （P〈0.05）, but Bax activity, Cyt C release and apoptosis rate showed no significant difference among them. However, in G4, G5, and G6 groups, apoptosis rate of islet cells, NF-rd3 expression, Bax activity, and Cyt C release were all significantly increased, and insulin secretion was impaired as compared with G1, G2, and G3 groups （P〈0.05）. It was concluded that the exposure of islet cells to high glucose could induce islet cells apoptosis as well as impaired insulin secretion. The NF-κB signaling pathway and mitochondria pathway in islet cells might play some roles in the progressive loss of islet cells in diabetes. The inhibition of the NF-κB expression could be an effective strategy for protecting pancreatic islet cells.

Behavior of SiO_2 in the leaching process of alumina clinker with high concentration

It is essential for alumina production by alkaline process to know the behavior of minerals containing Al and Si in basic solution,and the behavior of SiO2 in the process of clinker leaching is an important portion. To study the behavior of SiO2 in the process of high concentration clinker leaching,experiments were carried out in home-made reactors. The results indicate that factors,such as temperature,time,Al2O3 concentration,as well as SiO2 concentration,have profound impact on the SiO2 and Al2O3 concen-tration of pregnant liquor during the high concentration leaching. However,sodium carbonate and free caustic soda concentrations have no remarkable effect on it,thus they are the secondary factors compared with Al2O3 concentration. The concentration of SiO2 in the pregnant liquor could be reduced to a lower level when the major effect parameters of this process are controlled properly.

Spectrum-Splitting Diffractive Optical Element of High Concentration Factor and High Optical Efficiency for Three-Junction Photovoltaics

A spectrum-splitting and beam-concentrating （SSBC） diffractive optical element （DOE） for three-junction pho- tovoltaics （PV） system is designed and fabricated by five-circ/e micro-fabrication. The incident solar light is efficiently split into three sub-spectrum ranges and strongly concentrated on the focal plane, which can be di- rectly utilized by suitable spectrum-matching solar cells. The system concentration factor reaches 12x. Moreover, the designed wavelengths （450nm, 550nm and 65Onto） are spatially distributed on the focal plane, in good agree- ment with the theoretical results. The average optical effic/ency of all the cells over the three designed wavelengths is 60.07%. The SSBC DOE with a high concentration factor and a high optical efficiency provides a cost-effective approach to achieve higher PV conversion efficieneies.

Large Eddy Simulation of the Particle Coagulation in High Concentration Particle-Laden Planar Jet Flow

Particle coagulation by Brownian motion is an important but difficult research topic.When particle volume concentration is larger than 0.1%,the classic SMOLUCHOWSKI equation is not applicative anymore.The high concentration coagulation,with HEINE＇s correction,source terms for the Taylor-series expansion method of moments（TEMOM） are firstly driven in this paper.Ultra-fine particle（d0？100 mm） with initial volume fraction f？1% coagulation in a planar jet turbulence flow is simulated via the large eddy simulation（LES）.The instantaneous and time-averaged particle distributions and the high concentration enhancement are given out.The particle number concentration distribution results show that the coagulation is more intense comparing to dilute case in previous research,especially near the nozzle exit.After jet flow is fully developed,the effect is much more obvious at the region between vortexes.The time-averaged γ（the high concentration enhance factor） distributes sharply and symmetrically about the jet centerline at the upstream,but becomes broad and flat at downstream where the cross-stream averaged γ fluctuates drastically.As a new attempt,this paper shows Brownian coagulation with high concentration also can be calculated via TEMOM appropriately,and the coagulation at the region between vortexes is about 1.38 times intensive of the dilute result calculated by the classic Smoluchowski theory.

Amperometric Enzyme Biosensor for the Determination of High Concentration Lactate in Whole Blood of Athletes

<正>Amperometric biosensor applied to the determination of high concentration lactate in serum and whole blood was described.The biosensor was constructed by gold electrode modified with nanoplatinum particles.Lactate oxidase (E.C.1.1.3.2) was immobilized at platinized activated gold electrode which was used for the determination of high concentration lactate at low potential (+0.2 V).The linear calibration graphs were obtained from 1 to 21 mmol·L~ (-1) lactate in serum and from 0.9 to 13.2 mmol.L~ (-1) lactate in whole blood.The correlation coefficients were 0.99 and 0.97,respectively at a steady-state response time of 50 s.

Experimental studies on resistance characteristics of high concentration red mud in pipeline transport

Red mud will flow in paste form under high pressure during pipeline transport.It belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation,homogeneous solid-liquids.In pipeline transport,its resistance char- acteristics will be influenced by such factors as grain size,velocity,concentration,density, grain composition and pipe diameter etc..With the independently developed small-sized tube-type pressure resistance test facility,studied the resistance characteristics of red mud concerning the three influencing factors,paste concentration,velocity and pipe diameter, which attract the most attention in projects.The fine grain size of the red mud is d_(50)= 13.02μm.According to the experimental results,the pressure loss in transport will in- crease along with the increase of velocity and will fall along with the increase of pipe di- ameter.A 1% difference in paste concentration will result in a 50%～100% difference in pipeline resistance loss.These experimental data is hoped to be direct guidance to the design of high concentration and viscous material pipeline transport system.

Study on Treatment Technologies of High Concentrations of Industrial Organic Wastewater

The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which can provide theoretical references for the choice of wastewater treatment process.

Diffusion Process of High Concentration Spikes in a Quasi-Homogeneous Turbulent Flow

When a mass spreads in a turbulent flow, areas with obviously high concentration of the mass compared with surrounding areas are formed by organized structures of turbulence. In this study, we extract the high concentration areas and investigate their diffusion process. For this purpose, a combination of Planar Laser Induced Fluorescence (PLIF) and Particle Image Velocimetry (PIV) techniques was employed to obtain simultaneously the two fields of the concentration of injected dye and of the velocity in a water turbulent channel flow. With focusing on a quasi-homogeneous turbulence in the channel central region, a series of PLIF and PIV images were acquired at several different downstream positions. We applied a conditional sampling technique to the PLIF images to extract the high concentration areas, or spikes, and calculated the conditional-averaged statistics of the extracted areas such as length scale, mean concentration, and turbulent diffusion coefficient. We found that the averaged length scale was constant with downstream distance from the diffusion source and was smaller than integral scale of the turbulent eddies. The spanwise distribution of the mean concentration was basically Gaussian, and the spanwise width of the spikes increased linearly with downstream distance from the diffusion source. Moreover, the turbulent diffusion coefficient was found to increase in proportion to the spanwise distance from the source. These results reveal aspects different from those of regular mass diffusion and let us conclude that the diffusion process of the spikes differs from that of regular mass diffusion.

Analysis of High Concentration Spikes Appearing in Mass Plume in Nearly Homogeneous Turbulent Flow Based on the PDF Transport Equation

To evaluate the pollutant dispersion in background turbulent flows, most researches focus on statistical variation of concentrations or its fluctuations. However, those time-averaged quantities may be insufficient for risk assessment, because there emerge many high-intensity pollutant areas in the instantaneous concentration field. In this study, we tried to estimate the frequency of appearance of the high concentration areas in a turbulent flow based on the Probability Density Function (PDF) of concentration. The high concentration area was recognized by two conditions based on the concentration and the concentration gradient values. We considered that the estimation equation for the frequency of appearance of the recognized areas consisted of two terms based on each condition. In order to represent the two terms with physical quantities of velocity and concentration fields, simultaneous PIV (Particle Image Velocimetry) and PLIF (Planar Laser-Induced Fluorescence) measurement and PLIF time-serial measurement were performed in a quasi-homogeneous turbulent flow. According to the experimental results, one of the terms, related to the condition of the concentration, was found to be represented by the concentration PDF, while the other term, by the streamwise mean velocity and the integral length scale of the turbulent flow. Based on the results, we developed an estimation equation including the concentration PDF and the flow features of mean velocity and integral scale of turbulence. In the area where the concentration PDF was a Gaussian one, the difference between the frequencies of appearance estimated by the equation and calculated from the experimental data was within 25%, which showed good accuracy of our proposed estimation equation. Therefore, our proposed equation is feasible for estimating the frequency of appearance of high concentration areas in a limited area in turbulent mass diffusion.

Practice of High Concentration Sludge for Efficient Nutrient Removal from Municipal Sewage

ECOSUNIDE is a new activated sludge process based on the sludge concentration optimization theory.With it,we carried out a high sludge concentration by changing influent mode and distributing carbon source in a reasonable way,which can improve the ecological superiority of nitrification and denitrification for the growth of phosphorous accumulating organisms(PAOs)and nitrifiers and raised the nutrient removal efficiency of municipal sewage treatment plants.In 2007,we adopted this technique in Linyi Sewage Treatment Plant in Shandong Province,China.After the reconstruction,we achieved the high efficiency of nutrient removal with low investment under the dynamic load of the secondary sewage treatment plant.The effluent water qualities meet the classⅠ-A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002)and the rest effluent indexes meet the classⅠ-B criteria.Besides,we have above 20% operating cost cut by stopping the internal reflux without power charge increased and any new pool structures built.

Effects of Controlled Atmospheres with High_O_2 or High_CO_2 Concentrations on Postharvest Physiology and Storability of "Napoleon" Sweet Cherry

Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.

Preparation of high concentration polyaluminum chloride by chemical synthesis-membrane distillation method with self-made hollow fiber membrane

A method of direct contact membrane distillation （DCMD） with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride （PACl） with high Alb content based on chemical synthesis. The permeate flux and Al species distribution were investigated. The experimental results showed that the permeate flux decreased from 14 to 6 kg/（m2·hr） at the end of the DCMD process, which can be mainly attributed to the formation of NaCl deposits on the membrane surface. The Alb content decreased slightly, only from 86.3% to 84.4%, when the DCMD experiment finished, correspondingly the Alc content increased slightly from 7.2% to 8.5%, and the Ala content remained at 7% during the whole DCMD process. A PACl with Alb content of 84% at total aluminum concentration 2.2 mol/L was successfully prepared by the chemical synthesis-DCMD method.

EXPERIMENTAL INVESTIGATIONS ON DIFFUSION CHARACTERISTICS OF HIGH CONCENTRATION JET FLOW IN NEAR REGION

WT5”BZ]The diffusion characteristics of the high concentration jet flow issued from a round nozzle above the free surface into moving waterbody were experimentally investigated. By means of flow visualization technique, the diffusion behavior of the high concentration jet was observed and analysed, Concentration distribution in the near region was obtained by sampling and quantitative measurements. Experimental results indicate that the diffusion mechanics of the high concentration jet flow are greatly influenced by initial momentum, buoyancy, turbulent structure, ambient current and boundary conditions, showing complicated flow patterns and concentration distribution characteristics that are different from previous results for submerged jets. [WT5”HZ]