Effect of bubble morphology and behavior on power consumption in non-Newtonian fluids’aeration process

Due to a prolonged operation time and low mass transfer efficiency, the primary challenge in the aeration process of non-Newtonian fluids is the high energy consumption, which is closely related to the form and rate of impeller, ventilation, rheological properties and bubble morphology in the reactor. In this perspective, through optimal computational fluid dynamics models and experiments, the relationship between power consumption, volumetric mass transfer rate(kLa) and initial bubble size(d0) was constructed to establish an efficient operation mode for the aeration process of non-Newtonian fluids. It was found that reducing the d0could significantly increase the oxygen mass transfer rate, resulting in an obvious decrease in the ventilation volume and impeller speed. When d0was regulated within 2-5 mm,an optimal kLa could be achieved, and 21% of power consumption could be saved, compared to the case of bubbles with a diameter of 10 mm.

Strategies for Rational Design of High-Power Lithium-ion Batteries

Lithium-ion batteries(LIBs)have shown considerable promise as an energy storage system due to their high conversion efficiency,size options(from coin cell to grid storage),and free of gaseous exhaust.For LIBs,power density and energy density are two of the most important parameters for their practical use,and the power density is the key factor for applications such as fast-charging electric vehicles,high-power portable tools,and power grid stabilization.A high rate of performance is also required for devices that store electrical energy from seasonal or irregular energy sources,such as wind energy and wave energy.Significant efforts have been made over the last several years to improve the power density of LIBs through anodes,cathodes,and electrolytes,and much progress has been made.To provide a comprehensive picture of these recent achievements,this review discusses the progress made in high-power LIBs from 2013 to the present,including general and fundamental principles of high-power LIBs,challenges facing LIB development today,and an outlook for future LIB development.

THE CALCULATION OF RATE CONSTANT OF ELECTRON TRANSFER REACTION AT ELECTRODES

After the electron transfers from the metal electrode to the Fe3+(H2O)(6) ion, the free energy of activation of this electron transfer reaction is calculated, then using the transition probability which is calculated by the perturbed degeneration theory and the Fermi golden rule,, the rate constant is gotten. Compared with the experimental results, it is satisfactory.

Analyzing Service Rates for File Transfers in Peer-to-peer File Sharing Systems

When examining the file transfer performance in a peer-to-peer file sharing system, a fundamental problem is how to describe the service rate for a file transfer. In this paper, the problem is examined by analyzing the distribution of server-like nodes' upstream-bandwidth among their concurrent transfers. A sufficient condition for the service rate, what a receiver obtains for downloading a file, to asymptotically be uniform is presented. On the aggregate service rate for transferring a file in a system, a sufficient condition for it to asymptotically follow a Zipf distribution is presented. These asymptotic equalities are both in the mean square sense. These analyses and the sufficient conditions provide a mathematic base for modeling file transfer processes in peer-to-peer file sharing systems.

Changes of Chorophyll protein Complexes and Photosynthetic Activities of Chloroplasts from Lotus (Nelumbo nucifera) Seeds Germinating in Light

The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of chlorophyll_protein complexes showed that there was only the light harvesting chlorophyll a/b protein complex from PSⅡ (LHCⅡ) precursor in chloroplast from lotus seeds germinated for 2 to 6 days, while LHC Ⅱ 1, and the chlorophyll_protein complex of PSⅠ (CPⅠ) appeared on the 8th day of germination and PSⅡ reaction center complex appeared later. Studies on the polypeptides composition of the chloroplast revealed the following results: 1) Small amount of the 27 kD polypeptide was synthesized in invisible light; 2) The 30 kD polypeptide existed previously in the plumules of the dry seeds; 3) The amount of the 30 kD polypeptide was more than any other polypeptides before germination and decreased gradually throughout germination, while the 27 kD polypeptide changed in the opposite way; 4) In the process of germination, measurement of the electron transport rate and the fluorescence induction kinetics at room temperature showed that PSⅡ activities and efficiency of primary light energy transformation were only experimentally measurable after 7 days of germination and gradually increased afterwards. At the same time, the chl a/b ratio rose from the lower value to normal; 5) The changes of chloroplast membrane components and its functions are concomitant in concert with that of the ultrastructure of chloroplast membranes during germination, as shown in our earlier work . The results have proved again that a different developmental pathway of chloroplast is likely to exist in the lotus plumules, which might provide an important clue for N. nucifera in having an unique position in the phylogeny of the angiosperm.

Research on development of surface-roughness variation and control technology of the automotive plates and rolls

Surface roughness considerably influences the stamping and coating performance of the automotive plates;however,the surface roughness of the automotive plates is transferred from the roll during the rolling process.Therefore,the variation and control technology regarding the roughness of the automotive plates and rolls has drawn increasing attention from researchers in China and around the globe.In this study,the research methods,analytical techniques,prediction models,transfer rules,and control technologies regarding the surface roughness of the automotive plates and rolls were reviewed.Among these,an online measurement system for automotive-plate and roll surface roughness has been applied to the production lines of Germany,China,Belgium,Holland,Austria,and other countries and has achieved remarkable results.Online measurement and timely feedback regarding the automotive-plate and roll surface roughness are needed to ensure favorable conditions for the establishment of automotive-plate roughness-control measurement.

Simultaneous nitrogen and phosphor removal in an aerobic submerged membrane bioreactor

Simultaneous nitrification and denitrification （SND） effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids （MLSS） 19--20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor （MBR） and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2-- 0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate （PFS） addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances （EPS） of mixed liquor.

Mass Transfer During Osmotic Dehydration Using Acoustic Cavitation

An experimental study on intensifying osmotic dehydration was carried out ina state of nature and with acoustic cavitation of different cavitating intensity (0.5A, 0.7A and0.9A) respectively, in which the material is apple slice of 5mm thickness. The result showed thatacoustic cavitation remarkably enhanced the osmotic dehydration, and the water loss was acceleratedwith the increase of cavitating intensity. The water diffusivity coefficients ranged from1.8x10^(-10)m^2·s^(-1) at 0.5A to 2.6x10^(-10)m^2·s^(-1) at 0.9A, and solute diffusivitycoefficients ranged from 3.5x10^(-11) m^2·s^(-1) at 0.5A to 4.6X10^(-11)m^2·s^(-1) at 0.9A. On thebasis of experiments, a mathematical model was established about mass transfer during osmoticdehydration, and the numerical simulation was carried out. The calculated results agree well withexperimental data, and represent the rule of mass transfer during osmotic dehydration intensified byacoustic cavitation.

Heat transfer intensification in hydromagnetic and radiative 3D unsteady flow regimes: A comparative theoretical investigation for aluminum and γ-aluminum oxides nanoparticles

This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equations is carried out successfully by means of similarity variables.Then,the resultant nonlinear nature of flow model is treated numerically via Runge-Kutta scheme.The characteristics of various pertinent flow parameters on the velocity,temperature,streamlines and isotherms are discussed graphically.It is inspected that the Lorentz forces favors the rotational velocity and rotational parameter opposes it.Intensification in the nanofluids temperature is observed for volumetric fraction and thermal radiation parameter and dominating trend is noted for γ-aluminum nanofluid.Furthermore,for higher rotational parameter,reverse flow is investigated.To provoke the validity of the present work,comparison between current and literature results is presented which shows an excellent agreement.It is examined that rotation favors the velocity of the fluid and more radiative fluid enhances the fluid temperature.Moreover,it is inspected that upturns in volumetric fraction improves the thermal and electrical conductivities.

Diagnostic Value of Quantitative Parameters of DCE-MRI in Endometrial Carcinoma and Its Correlation with Clinicopathological Factors

In the study,108 patients with endometrial cancer were selected as the observation group,and 105 patients with benign endometrial lesions were selected as the control group.After DCE-MRI examination,it was found that the volume transfer constant(K^(trans)),rate constant(K_(e))and extracellular space volume ratio(V_(e))in the observation group were higher than those in the control group(P<0.05).The area under curve(AUC)of combined K^(trans),K_(e) and V_(e) values in the diagnosis of endometrial cancer was 0.841.The values of K^(trans),K_(e )and V_(e) were positively correlated with the clinical stage and the degree of muscular invasion,but negatively correlated with the degree of differentiation(P<0.05).The results of the study suggested that DCE-MRI quantitative parameters have a certain value in the differential diagnosis of endometrial cancer,which helped to further distinguish the degree of muscular invasion,clinical stage,and differentiation of endometrial cancer patients.

Effects of fluid recirculation on mass transfer from the arterial surface to flowing blood

The effect of disturbed flow on the mass trans- fer from arterial surface to flowing blood was studied nu- merically, and the results were compared with that of our previous work. The arterial wall was assumed to be vis- coelastic and the blood was assumed to be incompressible and non-Newtonian fluid, which is more close to human arte- rial system. Numerical results indicated that the mass trans- fer from the arterial surface to flowing blood in regions of disturbed flow is positively related with the wall shear rates and it is significantly enhanced in regions of disturbed flow with a local minimum around the reattachment point which is higher than the average value of the downstream. There- fore, it may be implied that the accumulation of cholesterol or lipids within atheromatous plaques is not caused by the reduced efflux of cholesterol or lipids, but by the infiltration of the LDL （low-density lipoprotein） from the flowing blood to the arterial wall.

One Method for Improving RAID5 Performance

As a kind of parallel storage system, RAID5 has been becoming a popular solution for providing better performance at low cost and without sacrificing much redundant data, its main disadvantage is poor performance. It is a general method to improve RAID5 performance by using cache. However, it often happens that the data is not hit in cache, in this case, the RAID5 performance also will be very poor. The method based on combination of disk I/O operations has been proposed for impriving the I/O response time through reducing the number of low-level operations. According to theoretic analysis and experimental test, we find that RAID5 access time and data transfer rate could be largely improved than conventional method.

Desorption Kinetics of Volatile in Condensed Mode Polyethylene Process

In this paper the desorption kinetics of volatile in condensed mode polyethylene process is studied through experiments. It is found that though the residual volatile in particles at the later stage of desorption accounts for a relatively small portion of the total quantity, the desorption of this part of volatile requires much longer time than at the earlier stage. For high requirement of devolatilization, the total time needed will be predominately determined by the residual amount of volatile in particles. Temperature has greater effect on the desorption rate than other influence factors, especially in the later period of desorption. A model is proposed to calculate the volatile desorption rate for condensed mode polyethylene process.

Modeling of Heat Transfer and Steam Condensation Inside a Horizontal Flattened Tube

This work investigates the steam condensation phenomena in an air-cooled condenser.The considered horizontal flattened tube has a 30 mm hydraulic diameter,and its length is a function of the steam quality with a limit value between 0.95 and 0.05.The mass flow rate ranges from 4 to 40 kg/m^(2).s with a saturated temperature spanning an interval from 40°C to 80°C.A special approach has been implemented using the Engineering Equation Solver(EES)to solve a series of equations for the two-phase flow pattern and the related heat transfer coefficients.A wavy-stratified structure of the two-phase flow has been found when the mass rate was between 4 and 24 kg/m^(2).s.In contrast,an initially annular flow is gradually converted into a wavy stratified flow(due to the condensation process taking place inside the flattened tube)when the considered range ranges from 32 to 40 kg/m^(2).s.

The Intermolecular Interaction in Self-Assembled Monolayers on Gold Electrode

The intermolecular interaction in an azobenzene self-assembled monolayers (SAMs) on gold electrode was investigated by controlling the assembling time and using mixed self-assembled techniques, and the variation of apparent electron transfer rate constant (k(s)) of azobenzene SAMs with different molecular packing density is reported.

Three-dimensional simulation of interfacial convection in CO_2–ethanol system by hybrid lattice Boltzmann method with experimental validation

By using a hybrid lattice-Boltzmann–finite-difference method(hybrid LBM–FDM method),three-dimensional simulations of solutal interfacial convection were conducted for the process of CO2absorption into ethanol.A self-renewal interface model is adopted as an interfacial perturbation model.The simulation results revealed some three-dimensional features of the induced interfacial convection,such as the development of diverging cellular flow and Rayleigh plume-like convection in liquid phase.The concentration distribution of the simulation result is validated and found to be in well agreement with the Schlieren visualization results qualitatively.Additionally,the mass transfer enhancements by interfacial convection were investigated via both simulation and experiment for the absorption process,and the mass transfer is shown to be enhanced by the interfacial convection by about two-fold comparing with that by diffusion.

Similarity Solutions for Laminar Boundary Layer Flow of Darcian Fluid over Horizontal Plate with a Convective Boundary Condition

This paper considers the problem of hydrodynamics and thermal boundary layers of Darcy flow over horizontal surface embedded in a porous medium. The solutions of such problems for the cases of uniform surface temperature and variable surface temperature have been studied and analysed in many papers. This paper, however, attempts to find similarity solutions for the Darcy flow problem with a convective boundary condition at the plate surface. It is found that the solution is possible when the heat transfer coefficient is proportional to x–2/3. The numerical solutions thus obtained are analyzed for a range of values of the parameter characterizing the hot fluid convection process. Analytical expressions are provided for local surface heat flux and total surface heat transfer rate while the flow variables are discussed graphically.

The Human Capital Return and Social Integration of Migrants in China

From the perspective of migrants ＇self-selection and skill transferability theories, this paper compares human capital return rates of different migrant groups in urban China and discuss the possibility of economic status identified by migrants as local labors. Results suggest that positive self-selection works for all types of migrant labors. Migrant workers with non-agricultural household registration or feinong hukou have no trouble to be integrated into the labor market of destination. They even have higher income and human capital return rates than local urban workers. Newly-arrived migrant peasants earn less than local labors. However, after a certain period, the skilled migrant workers catch up with local labors and are economically integrated into the local labor market while the low-skilled migrant group still earns less. Therefore the integration of migrant labors in urban labor market is yet a kind of segregated integration.

The Effects of Cells Density Arrangement in Chlorella vulgaris Culture to C02 Fixation and Essential Substances Production

Global warming that triggered the climate change is largely due to increased CO2 concentrations. Utilization of Chlorella sp. to reduce CO2 gas is a promising potential. Chlorella can efficiently reduce CO2 and easily be adapted into the photobioreactor system engineering. In this research, the type of microalgae which is used is Chlorella vulgaris in Benneck medium. The system of used reactor is mid-scale bubble column photobioreactor flowed by air which contains 5% CO2. Chlorella vulgaris biomass production will be increased by adjusting the cell density in the photobioreactor. These arrangements will be implemented through a continuous treatment of cell entrapment. The arrangement of cell density in continuous reactor has been proven to increase production of Chlorella vulgaris biomass about 1.25 times more than cultivation without arrangement of cell density by using the same number of inoculums. The results also have shown that the average rate of CO2 fixation and Carbon Transfer Rate （CTR） are obtained at cell entrapment condition about 17 times larger. Continuous cellular entrapment method is very potential to be developed as a method for the production of biomass. Lipids and carotene that have been produced from Ch. vulgaris respectively are 18.24% and 9.42 ppm.

Lattice Boltzmann Simulation of Magnetic Field Effect on Electrically Conducting Fluid at Inclined Angles in Rayleigh-Bénard Convection

The magneto-hydrodynamics(MHD)effect is studied at different inclined angles in Rayleigh-Bénard(RB)convection inside a rectangular enclosure using the lattice Boltzmann method(LBM).The enclosure is filled with electrically conducting fluids of different characteristics.These characteristics are defined by Prandtl number,Pr.The considered Pr values for this study are 10 and 70.The influence of other dimensionless parameters Rayleigh numbers Ra=10^(3);10^(4);10^(5);10^(6) and Hartmann numbers Ha=0,10,25,50,100,on fluid flow and heat transfer,are also investigated considering different inclined anglesφof magnetic field by analyzing computed local Nusselt numbers and average Nusselt numbers.The results of the study show the undoubted prediction capability of LBM for the current problem.The simulated results demonstrate that the augmentation in heat transfer is directly related to Ra values,but it is opposite while observing the characteristics of Ha values.However,it is also found thatφhas a significant impact on heat transfer for different fluids.Besides,isotherms are found to be always parallel to the horizontal axis at Ra=10^(3) as conduction overcomes the convection in the heat transfer,but this behaviour is not seen at Ra=10^(4) when Ha>25.Furthermore,at Ra=10^(6),oscillatory instability appears but LBM is still able to provide a complete map of this predicted behavior.An appropriate validation with previous numerical studies demonstrates the accuracy of the present approach.