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The Aharonov-Bohm Effect and Transport Properties in Graphene Nanostructures

Abstract

This paper investigates the possibility to improve the filtering process of flue gas by separation of suspended nanoparticle using dielectrophoresis. The study focuses on the particles having an average radius of about 50-150 nm, that cannot be filtrated by classical techniques but have a harmful effect for environment and human health. The size distribution nanoparticles collected from the flue gas filters of a hazardous waste incinerator plant were evaluated. Based on obtained experimental data and a proposed mathematical model, the concentration distribution of nanoparticle suspended in flue gas inside a microfluidic separation device was analyzed by numerical simulations, using the finite element method. The performances of the device were described in terms of three new specific quantities related to the separation process, namely Recovery, Purity and Separation Efficiency. The simulations could provide the optimal values of control parameters for separation process, and aim to be a useful tool in designing microfluidic devices for separating nanoparticle from combustion gases.

Open access
Performance Characteristics of Panel Filters for Internal Combustion Engine Inlet Air Working in a Two-Stage Configuration

Abstract

Air filtration conditions in a single-stage and a two-stage filtration system (multicyclone-porous panel filter) are presented. Allowable flow resistance ∆ pfdop values reducing the air filter service life are specified. The benefits of using a multicyclone as a first stage of air filtration, including improved mobility and extended service life, are discussed. Criteria for selecting the filter media for the automobile air intake system using an absorption coefficient of dust km determined at a specific allowable flow resistance ∆pfdop are specified. New methods and conditions to determine the absorption coefficient of dust km for article filter and non-woven fabric filter in a single-stage and a two-stage filtration system are developed and presented. The separation efficiency and separation performance as well as the flow resistance characteristics of the filter set including a single cyclone and a filter element with a specially selected filter medium surface area are tested. Absorption coefficients of dust km for the tested paper filter and non-woven fabric filter were determined for an allowable flow resistance. The effects of dust particle size distribution in the air downstream of the cyclone on reducing the absorption coefficient of dust of the paper filter and non-woven fabric filter in a two-stage filtration system are shown.

Open access
Centrifugal Compressor Performance Improvement through Multi Splitter Impeller

Abstract

In the paper, a back swept impeller of centrifugal compressor is experimentally studied and numerically validated and modified to increase its pressure ratio and improve efficiency, as well as to analyse the effect of splitter blade location between two main blades. The back swept multi splitter blade impeller was designed with a big splitter positioned close to the main blade suction surface and a smaller splitter close to the pressure surface. Adding this multi splitter improves the overall performance of the modified impeller due to less intensive flow separation and smaller pressure loss. In particular, the total pressure ratio was observed to increase from 4.1 to 4.4, with one percent increase in efficiency.

Open access
Comparing monolithic and fused core HPLC columns for fast chromatographic analysis of fat-soluble vitamins

XTerra MS C18, based on modeling approaches, Anal. Bioanal. Chem. 405 (2013) 2219-2231; DOI: 10.1007/s00216-012-6448-y. 3. T. Reddy, G. Balammal and A. Kumar, Ultra performance liquid chromatography: an introduction and review, Int. J. Pharm. Res. Anal. 2 (2012) 24-31. 4. J. M. Cunliffe and T. D. Maloney, Fused-core particle technology as an alternative to sub-2-mm particles to achieve high separation efficiency with low backpressure, J. Sep. Sci. 30 (2007) 3104-3109; DOI: 10.1002/jssc.200700260. 5. J. Kirkland, T

Open access
A fluidized layer of granular material used for the separation of particulate impurities in drinking water treatment

fluidized layer of granular material in the treatment of surface water. Part 1: Aggregation efficiency of the layer. J. Water SRT - Aqua, 48 , 1, 24-30. MUTL S., KNESL B., POLASEK P., 2000: Application of a fluidized layer of granular material in the treatment of surface water. Part 2: Separation efficiency of the layer. J. Water SRT - Aqua, 49 , 4, 181-202. MUTL S., POLASEK P., PIVOKONSKY M., KLOUCEK, O., 2006: The influence of G and T on the course of aggregation in treatment of medium polluted surface water. Water

Open access
Multidimensional gas chromatography and its applications in food and environmental analysis

Abstract

This review deals with overview of methods of multidimensional gas chromatography (MDGC), the classical meaning- conventional heart-cut MDGC, and the comprehensive two-dimensional gas chromatography (GC×GC). MDGC is widely used because it increases required separation efficiency, which cannot be achieved by one-dimensional gas chromatography. Selected applications in food quality and safety, monitoring of environment, food authentication are summarized. This review summarizes the advances and applications of MDGC that have been published over last 10 years.

Open access
An underestimated technique. Does pressurized and pressure-assisted capillary electrochromatography have potential in drug and pharmacological-active compounds analysis?

Abstract

Pharmaceutical analysis guarantees patient safety all over the world. Thus, continuous development of existing analytical techniques is still very important. Pressurized capillary electrochromatography and pressure-assisted capillary electrochromatography are hybrid separation techniques that combine the selectivity of liquid chromatography and the high separation efficiency of capillary electrophoresis. They use a smaller amount of reagents and samples, hence, reducing the total cost of analysis. Therefore they have found application in a number of pharmaceutical and biomedical analysis. This review article focuses on the use and importance of pressurized and pressure-assisted capillary electrochromatography in pharmaceutical and biomedical analysis, taking into account types of detectors and capillaries used. Despite the fact that pressurized capillary electrochromatography and pressure assisted capillary electrochromatography offer many possibilities and have been available for over a dozen years, they are still underdevelopment and not fully explored.

Open access
Simulated moving bed chromatography separation of galacto-oligosaccharides

Abstract

A mixture of galacto-oligosaccharides and non-prebiotic sugars was separated using a simulated moving bed unit equipped with eight packed-bed columns of a cation exchanger. In order to determine operating conditions using triangle theory, equilibrium adsorption isotherms of galactose, glucose, lactose, tri- and tetragalacto-oligosaccharide were measured. It was found that each column of the SMB unit had a maximum separation efficiency of more than 3000 theoretical plates. The achieved purity of galacto-oligosaccharides in the raffinate stream was 99.9 %, similarly 99.9 % of extract was formed by non-prebiotic sugars lactose, glucose and galactose. The productivities in the raffinate and extract, were 0.6 g/(L h) and 2.4 g/(L h), respectively.

Open access
Effect of Modified Mechanical Treatment Facilities on SRF Yield in Korea

Abstract

An SRF plant which can produce 100 ton/month of SRF, one of the largest manufacturing plants in Korea, was investigated in this study. The actual operated SRF yield at 21.7 % that showed a lower yield than expected; originally designed value was 25.0%. The cause of these results was the difference between characteristics of MSW applied to this plant originally and that which was actual incoming. The MSW led to decrease the separation efficiency of the mechanical treatment process. Thus, each element of the facility was modified. After modification, the SRF yield increased to 30.9%, whereas the physico-chemical properties of SRF were satisfied with domestic standard of SRF regardless of modifying MT facilities.

Open access
Use of ionic liquids in extraction

Abstract

In order to separate liquid mixtures, common distillation is not always suitable, especially if relative volatility of the mixture components is close to or equals unity, thus avoiding separation based on the vapor enrichment by more volatile component. To overcome this limitation of distillation, several alternatives were suggested including pressure swing and extraction distillation. Another, principally different, separation method used for the liquid mixtures separation is liquid-liquid extraction. Separation efficiency of this method is closely related to the basic extraction solvent characteristics, capacity and selectivity. In order to minimize costs connected with extraction, new extraction solvents are developed, among which ionic liquids show high potential due to their tunable properties. Here, efficiency of traditional extraction solvent, benzene, was compared to that of tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)imide ionic liquid in separation of ethanol from its aqueous solution. The comparison was assessed on the base of results of a counter-current extractor simulation. Further, some economic aspects of this separation procedure were discussed. Optimum consumption of extraction solvent was identified taking into account alcohol-to-water molar (mass) ratio in the final extract as optimization criterion.

Open access