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AbstractA convenient criterion is derived for the characterization of chromatographic stationary phases capable of providing an efficient and rapid analysis of a given class of mixtures based on a theoretical analysis of the dependence of specific efficiency on capacity. The criterion implicitly contains information about the internal structure of the column packing grain. The derivation of an expression for the criterion is accompanied by a theoretical substantiation of the interval for the working grain size of the column packing, which has a capacity and represents the region of particle diffusion. It is shown that the ratios are universal regardless of the type of the chromatographic process. A new characteristic of the quality of column packing can be called its performance factor, which shows the ratio of the actual to the maximum performance of the chromatographic system with a given selectivity. Examples of determining the quality criterion of a stationary phase for ion chromatography are given.

Fibrous materials are prominent among novel chromatographic supports for the separation and purification of biomolecules. In this work, strong anion exchange, quaternary ammonium (Q) functional fibrous adsorbents were evaluated with regards to their physical and functional characteristics. A column packed with Q fibrous adsorbent illustrated the good column packing efficiency of theoretical plate height (H) values and higher permeability coefficients (>0.9 × 10−7 cm2) than commercial adsorbents. For pulse experiments with acetone and lactoferrin as tracers under nonbinding conditions, the total porosity (for acetone) and the interstitial porosity (for lactoferrin) measured 0.97 and 0.47, respectively. The total ionic capacity of the chemically-functionalized Q fiber was 0.51 mmol/mL. The results indicated that the Q fiber had a static binding capacity of 140 mg/mL and a dynamic binding capacity (DBC) of 76 mg/mL for bovine serum albumin (BSA) and showed a linearly-scalable factor (~110 mL) for a column volume with high capacity and high throughput. Furthermore, this adsorptive material had the ability to bind the high molecular weight protein, thyroglobulin, with a capacity of 6 mg/mL. This work demonstrated the column-packed Q fibrous adsorption system as a potential chromatography support that exhibits high capacity at higher flow rates.

This study focuses on investigating the hydrodynamics using computational fluid dynamics (CFD) simulation and residence time distribution (RTD) within a trickle bed reactor (TBR). CFD simulation was performed on a packed column filled with structured packing of glass beads, while the experiments for RTD studies were conducted in a TBR filled with random packing of Raschig rings. The geometry of TBR and size of packing during CFD simulation was kept close to that of the experimental setup. CFD simulation results were obtained which predicted the flow of fluid through the TBR at different vertical planes along the column. The fluctuations of liquid velocity at various positions inside the reactor were predicted by the CFD model. RTD studies were performed for both pulse input and step input using a non-reactive tracer such as sodium hydroxide. The flowrate of water was varied from 0.6 LPH to 6 LPH for pulse input, while for step input the ratio of water to tracer flowrates was kept at 1:1, 1:2 and 2:1. This study allows us to understand how hydrodynamics and residence time distribution may have an effect on the performance of TBR.

This work presents the theoretical and experimental investigation of a solar-powered humidification dehumidification desalination (HDD) system with different humidifier packing materials and a two-stage bubble column dehumidifier (BCD). Naturally available coconut shells (CS) and coconut shells with drilled holes (CSH) on the surface to improve water permeability were used as packing materials in the humidifier, and their performance was compared with that of commercial-type pall ring (PR) and raschig ring (RR) packings. An in-house developed numerical model of the HDD system in conjunction with a flat plate solar water collector was used in this study. Steady-state experimental results showed that CSH packing exhibited the highest volumetric mass transfer coefficient (0.00852 kg/s), resulting in maximum humidifier efficiency (96%) and freshwater yield (2.16 kg/hr), followed by PR (0.00841 kg/s, 94%, and 2.137 kg/hr), CS (0.00831 kg/s, 90%, and 2.127 kg/hr), and RR (0.0081 kg/s, 81%, and 2.087 kg/hr) at feedwater mass flow rate of 1.5 kg/min and humidifier inlet temperature of 75 ∘ C . Furthermore, transient outdoor test results showed that using a two-stage configuration in a BCD increased the daily average effectiveness to 0.93, as against 0.79 for a single-stage BCD. Employing CSH instead of PR and RR packings in the humidifier reduced freshwater costs by 6.2% and 7.6%, respectively.

The UK Biobank (UKB) is a resource that includes detailed health-related data on about 500,000 individuals and is available to the research community. However, several obstacles limit immediate analysis of the data: data files vary in format, may be very large, and have numerical codes for column names. ukbtools removes all the upfront data wrangling required to get a single dataset for statistical analysis. All associated data files are merged into a single dataset with descriptive column names. The package also provides tools to assist in quality control by exploring the primary demographics of subsets of participants; query of disease diagnoses for one or more individuals, and estimating disease frequency relative to a reference variable; and to retrieve genetic metadata. Having a dataset with meaningful variable names, a set of UKB-specific exploratory data analysis tools, disease query functions, and a set of helper functions to explore and write genetic metadata to file, will rapidly enable UKB users to undertake their research.

In the present study, hydrodynamics and mixing characteristics of packed bed biofilm reactor are compared by varying voidage using MBBR media and conventional packings. The mixing characteristics are studied using conductivity method. RTD at the entrance and exit of the column is studied and compared for all the packings. The flow approached plug flow with an increase in velocity (3.02 - 5.2 cm/s) and a decrease in voidage of packing (0.92 - MBBR, 0.833 – Raschig rings, 0.45 – Plastic balls).

The alkylated poly(styrene-divinylbenzene) (PSD) microspheres are attractive chromatographic column packings for high-performance liquid chromatography. In this paper, the butyl bonded PSD microspheres were prepared by the reaction of brominated PSD microspheres with n-butylmagnesium bromide. Fourier transform infrared (FTIR) spectroscopy and solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy were used to analyze the polymers. FTIR spectra analysis could establish the occurrence of bromination of PSD microspheres and the reaction of brominated PSD microspheres with n-butylmagnesium bromide. And 13 C NMR results illustrated that the Grignard reaction had the largest conversion at the 1-bromobutane adding amount of 0.05 mol according to the analysis of the peak height ratios. The prepared microspheres are expected to serve as chromatographic packing.

A formula is derived for calculating porosity with an ordered installation of Raschig rings in the wall region of a packed column. Comparative calculations are made for the porosity in the wall region and the ordered arrangement of Raschig rings in rows inside the body of the apparatus specified in reference tables and determined using the theoretical formula. The effect the geometric dimensions (outer diameter and wall thickness) of Raschig rings, the inner diameter of the apparatus, and the number of freely installed rings have on the porosity in the wall area is demonstrated.

Carbitol acetate (CA) could be a remarkable for CO 2 absorption due to its high boiling point, low viscosity, and high CO 2 solubility. Using a laboratory-scale Raschig ring packed-column, mass transfer studies of CO 2 in carbitol acetate have been performed at ambient temperature and pressure. Liquid and gas side physical individual mass transfer coefficients (k L 0 a, k c 0 a) were determined by oxygen desorption method and by sulfur dioxide absorption into sodium hydroxide solution (NaOH), respectively. Also, gas side overall chemical and physical mass transfer coefficients (K c a, K c 0 a) were experimentally determined by the CO 2 absorption into NaOH solution and CA. Results show that K c a and K c 0 a increase with increasing gas and liquid velocities. The results also showed that (K c 0 a) CA and (K c a) NaOH were 2.2 and 2.5 times greater than that of water, respectively. It is known that the chemical absorption mechanism is more effective than the physical absorption mechanism. According to the (K c 0 a) water comparison, (K c 0 a) CA and (K c a) NaOH have almost shown close results. Carbitol acetate has been shown to be a potential absorbent for CO 2 absorption process and could be a viable alternative with further research and development. Also, nonlinear regression analyses were performed, and correlations were developed for mass transfer coefficients.

The article presents a comparative analysis of the methods for manufacturing polypropylene Raschig rings (taking account of consumption coefficients in manufacture of thermoplastic products) on the example of mass-exchange packings for the drying tower of a sulfuric acid plant. Graphical relationships and regression equations for Raschig ring (diameter 75 mm) mass-exchange packings made of polypropylene (taking account of the manufacturing method) are presented.