Increase In Number Of Stages Research Articles

Multi-stage chiral separation with electrospun chitin nanofiber membranes

Chitin nanofiber membranes were fabricated via electrospray deposition. The nanofiber membrane adsorbed l-isomer from racemic mixture of Glu and Phe in preference to the corresponding antipodes, while d-Lys was preferentially incorporated into the membrane. The adsorption isotherms revealed that all enantiomers studied in the present study were incorporated into the nanofiber membrane without any specific interaction, in other words, those were simply adsorbed. In membrane transport experiments, d-isomers were preferentially transported through the nanofiber membrane. In order to attain higher permselectivity, a multi-stage cascade separation was applied in the present study. As expected, the permselectivity toward d-enantiomer was enhanced exponentially with the increase in number of stages from one to five stages via three by applying a multi-stage cascade membrane separation.

Characterization and microwave absorption properties of ternary FeCl 3–NiCl 2–GICs

Ternary FeCl3-NiCl2-GICs were synthesized by the molten salt method. Natural graphite powder was used as host material and a mixture of FeCl3 and NiCl2 as intercalant. The stage structure,surface topography and components of the GICs were studied by XRD,SEM and EDS. The electrical conductivity and electromagnetic parameters were determined by a transmission reflection network analyzer. Results show that the host grap￣hite is expanded and its edges are eroded badly during intercalation. The degree of erosion levels off with an increase of stage number. For the FeCl3-NiCl2-GICs with different stages,the distribution of Cl is uniform in the graphite layers,while Fe and Ni is non-uniformly distributed in every flake. The percentage of Fe increases from the edge to the center of the FeCl3-NiCl2-GICs flake while Ni shows the opposite behavior. The resistivity of the FeCl3-NiCl2-GICs decreases first,then increases with an increase in stage number. The GICs have relatively good microwave absorption properties and their maximum theoretical reflection loss first decreases,then increases with increasing stage number. Stage-one FeCl3-NiCl2-GICs has the highest reflection loss,which is -10.3 dB when the thickness is 2 mm.

513 サボニウス風車の性能に及ぼす羽根車段数の影響(環境とエネルギー)

The purpose ofthis study is resolving the influence ofrotor stage number on Savonius rotor characteristics.Torque coeffucient, power coefficient, velocity distribution and turbulence intensity ofthree kinds of Savonius rotor were measured with Reynolds number was 4.1×10^4 and tip speed ratio of velocity distribution and turbulence intensity was 0.2,0.4,0.6,0.8.Tip speed ratio of maximum torque coefficient and the maximum power coefficient became low as the rotor stage number increases. Turbulence intensity of two stages rotor was lower than one stage rotor and three stages rotor in y-axis. In z-axis, differences ofvelocity by the influence ofrotor stage number were not found.

Removal of Dilute Nitric Acid by Anion Exchange Using a Countercurrent Multistage Fluidized-Bed Column

An ion-exchange experiment with a countercurrent multistage fluidized bed has been carried out. The nitrate ion was effectively removed from a dilute nitric acid solution by anion-exchange resins. The outlet concentration, Cout, coincides well with the one simulated on the basis of the ion-exchange equilibrium and the effective diffusivity, De, within the resin particle. The ion-exchange equilibrium of DIAION SA10A or WA10 with a HNO3 solution in the batch experiment is expressed by the Freundlich isotherm. The value of De measured with a fixed bed for ion exchange between an anion-exchange resin and a HNO3 solution was 1 × 10-12 m2/s for SA10A and 1.5 × 10-12 m2/s for WA10, respectively. Calculation of a multistage fluidized bed has shown that the removal of HNO3 is promoted with increasing stage number and increasing resin flow rate, while it decreases with increasing liquid flow rate. An increase in the stage number increases not only the removal fraction but also the ion loading of the resin.

Multistage affinity cross-flow filtration: mathematical modelling and analysis

A multistage affinity cross-flow filtration (mACFF) process for protein purification is proposed. The process is mathematically modelled taking into account a case of rapid equilibrium binding of a target protein to its macroligand. The process performance, i.e., dimensionless breakthrough volume (Qb+)and recovery yield (REC) to obtain a desired purity is analysed by computer simulations. The results indicate that Qb+increases with the increase of stage number (n) due to the increase of affinity binding efficiency. In addition, REC also increases with the increase of n, especially for lower affinity systems, even though the feed loading is the same as the corresponding breakthrough volume that increases with n. Thus both feed loading and recovery yield can be enhanced by raising the stage number. Incompletely permeable membranes reject the target and contaminant proteins. So they delay the appearance of the breakthrough point and compromise the contaminant washing efficiency. Hence although Qb+increases with the increase of membrane rejection coefficient (R), REC decreases when the feed loading equals that of Qb+. However, when the feed loading is kept unchanged and equals Qb+at R=0, REC does not decrease, but slightly increases with the increase of R. This result indicates that incompletely permeable membranes may also be employed for the mACFF process. In general, the model gives a predictive evaluation of the mACFF process successfully.

Syntheses of tin and lead fluoride graphite intercalation compounds and the phase transition of the tin fluoride compound

Abstract The reaction of tin tetrafluoride with graphite in liquid anhydrous hydrogen fluoride (AHF) in the presence of fluorine yields a stage-2 graphite intercalation compound (GIC) with an identity period I c = 11.53 A , whereas no intercalation reaction occurs without fluorine. With lead tetrafluoride, however, the reaction proceeds without fluorine yielding a stage-2 compound. X-ray diffraction and differential scanning calorimetry measurements on the SnF4-based GICs confirmed a two-dimensional phase transition over a wide temperature range from 120 to 170 K. The optical reflectivity in the UV-Vis region on the SnF4-based GICs has also been studied as a function of stage number. The experimental results were analyzed using the Blinowski-Rigaux model. It was found that the reflectivity minimum shifts towards lower energy with the increase of stage number. This behavior is attributed to the increase of carrier density. The charge transfer per carbon atom in CxSnF6 does not differ greatly from those in C6F and C16AsF5. The derived electrical conductivity of CxSnF6 is not as high as that of C16AsF5 owing to the shorter mean free path of the carriers in the former as a consequence of lattice defects generated in the course of the intercalation in the AHF solutions.

Structural properties of optimal production controllers in failure-prone manufacturing systems

A failure-prone manufacturing system with one part-type and multiple machine states is considered. Each machine state has a given production capacity but is associated with several possible failure stages. Although transition times between failure stages are assumed exponential, the existence of multiple stages within each machine state allows failure times to have a distribution more general than the exponential distribution. For such a system, it is shown that the well-known hedging point policy minimizes inventory and backlog costs for a constant demand rate. The value of the optimal hedging points is now a function of failure stage as well as machine state. By ordering machine states according to increasing distance from the zero capacity state and failure stages according to distance from the capacity reduction transition, we show that hedging points increase monotonically when the machine state number decreases or the stage number increases. This can be intuitively interpreted as follows: the closer to the zero capacity state the system is, the larger the hedging point should be. This structural property of the optimal control is very useful in searching for the optimal control or designing near-optimal controls.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis of Internally Multistaged Gas Permeator

Mathematical models have been developed for an internally multistaged gas permeator based on the perfect mixing case. A problem of oxygen enrichment from air has been selected to illustrate the performance of the permeator. It has been shown that the effect of the number of permeation stages on oxygen enrichment is significant when the number of permeation stages is increased from one to two or three, and its effect reduces with a further increase in stage number. The results further reveal that no matter how many permeation stages are employed, the higher degree of separation is only achievable at lower values of overall stage cuts compared to the conventional single-stage permeator.

Magnetic properties of stage 2 CoCl2-graphite intercalation compound

Abstract Magnetic graphite intercalation compounds (GICs) provide an ideal system for the systematic study of two-dimensional (2D) magnetic phase transitions. The magnetic intercalants such as CoCl2, NiCl2, and MnCl2, having layered structures of CdCl2 type, are intercalated into the interlamellar space between the graphite layers, forming a well-defined staging structure along the c-axis. For the stage N (= 1, 2, 3, …) GlC, the magnetic intercalate layers are separated periodically by N graphite layers along the c-axis. The repeat distance between adjacent magnetic intercalate layers increases as the stage number increases.

Simulation and optimal design of seeded continuous emulsion polymerization process

Simulation and optimal design of the reactor for the seeded continous emulsion polymerization process have been done in this work. An internal mixer (Toray Hi-Mixer) as seeder connected with a stirred tank is designed to correlate conversion, molecular weight, and MWD with the model simulation proposed. An optimal mean residence time of seeder \documentclass{article}\pagestyle{empty}\begin{document}$(\bar \theta _s)_c$\end{document} is found to lie between \documentclass{article}\pagestyle{empty}\begin{document}$(\bar \theta _1)$\end{document} and tin, where \documentclass{article}\pagestyle{empty}\begin{document}$(\bar \theta _1)_{{\rm opt}} = (3aS_0 /2r\eta N_a \alpha)^{3/5}$\end{document} and tin = 1.57(aS0/riηNA)3.5. The optimal design of the process is performed according to the above relations under several polymerization conditions. In general, the increase in number of stages inside the seeder can reduced the volume of CSTR for a required production. Molecular weight of products is increased by increasing the number of stages inside the seeder, by decrasing the concentration of the initiator, and by increasing the concentration of the emulsifier under the optimal conditons.

Optimization of multistage crosscurrent fluidized drying by a special algorithm of the discrete maximum principle with a constant hamiltonian

Optimization of multistage crosscurrent fluidized drying by a special algorithm of the discrete maximum principle with a constant hamiltonian