Different Types Of Columns Research Articles

Simultaneous determination of eight organic amines in desulfurization solution by ion chromatography

The applications of organic-amine desulfurization have steadily increased owing to its high efficiency, low cost, and low energy consumption. Different proportions of organic amines exert different effects on sulfur dioxide removal. Therefore, the accurate determination of different organic amines in the desulfurization solution is of great importance. The ion-chromatographic method for the detection of organic amines does not require a derivatization step, has simple pretreatment procedures, and allows for the simultaneous determination of many types of organic amines. In this study, a method based on ion chromatography was developed for the simultaneous determination of ethanolamine (MEA), diethylethanolamine (DEEA), n-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), hydroxyethylethylenediamine (AEEA), piperazine (PZ), n-hydroxyethylpiperazine (HEPZ), and diethylenetriamine (DETA). The separation efficiency of the eight organic amines in different types of columns, leaching solutions, and column temperatures were compared. The determination was performed using an IonPac CS17 column with column temperature of 35 ℃ and gradient leaching with methyl sulfonic acid (MSA) solution via the inhibition conductance method. Samples of the desulfurization solution were analyzed using ultrapure water filtered through a 0.22 μm nylon microporous filter membrane and an OnGuard Ⅱ RP column; thus, the pretreatment steps are simple. The eight organic amines showed a good linear relationship within a certain concentration range, and the coefficient of determinations (R2) were greater than 0.998. The limits of detection (LODs) and quantification (LOQs) were determined from the mass concentrations of the organic amines corresponding to signal-to-noise ratios (S/N) of 3 and 10, respectively. LODs of 0.02-0.08 mg/L and LOQs of 0.07-0.27 mg/L were determined from a 1.0 μL sample injection. The actual recoveries ranged from 93.0% to 111%, and the relative standard deviations (RSDs, n=5) ranged from 0.31% to 1.2%. The results indicated that the proposed method has good accuracy and precision; thus, it is suitable for the determination of various organic amines in desulfurization solution.

Gradient Retention Factor Concept Applied to Method Development for Peptide Analysis by Means of RP-HPLC.

Using the van Deemter model, the efficiency of three stationary phase systems in the analysis of a mixture of synthetic peptides was evaluated: (i) monolithic, (ii) packed, and (iii) core-shell columns, and it was shown that the efficiency of the monolithic column is superior to the others, specifically using it, the lowest values of H min (0.03 and 0.1 mm) were obtained, and additionally its efficiency was not significantly affected by increasing the flow. Using the concept of the gradient retention factor (k*), a method for chromatographic separation of a peptide complex mixture was designed, implemented, and optimized and then transferred from a packed column to a monolithic one. The results showed that it was possible to separate all components of the mixture using both evaluated columns; moreover, the analysis time was reduced from 70 to 10 min, conserving the critical pair resolution (1.4), by the transfer method using the k* concept. The method developed was tested against a mixture of doping peptides, showing that this method is efficient for separating peptides of various natures. This investigation is very useful for the development of methods for the analysis of complex peptide mixtures since it provides a systematic approach that can be extrapolated to different types of columns and instrumentation.

A chiral metal-organic cage [Fe4L6](ClO4)8 used for capillary gas chromatographic separations

Metal-organic cages (MOCs), as a promising class of crystalline porous materials with well-defined cavities, have attracted wide attention due to their multifarious potential applications in gas storage, host-guest chemistry, molecular recognition, separation, catalysis, sensing, and drug delivery and so on. Herein, we report that a chiral MOC [Fe4L6](ClO4)8 coated capillary column was fabricated for high-resolution gas chromatographic separation of various analytes, including n-alkanes, n-alcohols, positional isomers, aromatic hydrocarbon mixture, especially for racemic compounds. A series of racemic compounds such as alcohols, epoxides, aldehydes, ketones, ethers, esters, alkenes, sulfoxides and amino acid derivatives could be well separated on the [Fe4L6](ClO4)8 coated capillary column with high enantioselectivity and good reproducibility. Comparing the chiral resolution ability of the MOC [Fe4L6](ClO4)8 coated column with the commercial β-DEX 120 column and the porous organic cage (POC) CC10 coated column, the chiral MOC column can be complementary to the two different types of columns. The results show that the chiral MOC [Fe4L6](ClO4)8 exhibited excellent separation performance toward a wide range of organic compounds, which will be very attractive as a new chiral separation media and has potential application prospects in separation science.

Electromechanical Design and Manufacturing of Dynamic Buckling Test Rig Under Various Temperature Conditions

A column is a structural member that bears an axial compressive load and is more likely to fail due to buckling compared to material strength. Some of these columns work at a high temperature and this temperature affects the behavior of buckling. Therefore, the designer must take this factor (temperature) into consideration. For the purpose of studying the effect of different temperatures on the phenomenon of buckling under compression dynamic loads to evaluate the state of failure for different types of columns, the thermal buckling test device has been designed and manufactured. Using this rig, practical tests can be conducted on solid and hollow columns of different metals and diameters, and thus the safe critical load for the column can be predicted. This device was successful in evaluating the life of the columns made of aluminum alloy (6061-T6) when the buckling interacts with heat. The current study found that rising the temperature increases the failure under the buckling phenomenon.

Unified model for fully and partially FRP confined circular and square concrete columns subjected to axial compression

Even though the usage of Fiber-reinforced polymer (FRP) full confinement arrangement is a more reliable and efficient strengthening technique than a partially confining strategy, it might not be cost-effective in real cases of strengthening. Experimental researches have demonstrated that confinement strengthening strategy is more effective for the case of circular columns compared to its application on square columns. This paper is dedicated to introducing a new unified model for determining the concrete confinement characteristics of FRP fully/partially confined circular/square concrete columns subjected to axial compressive loading. Through unification, the variations of the key parameters can be evaluated more-widely based on a unified mathematical framework. Consequently, it leads to the continuity in the predictions of FRP confinement-induced improvements for the different types of columns, contrary to those obtained from models only applicable to a specified cross-section or confining system. The substantial influence of non-homogenous concrete expansion distribution at the horizontal and vertical directions is taken into account in the determination of confinement pressure, besides arching action, by following the concept of confinement efficiency factor. Since the confinement-induced improvement is a function of its confining stress path, a new methodology is proposed to predict global axial stress–strain relation of FRP confined concrete columns considering confinement path effect, based on an extensive set of experimental results including 418 test specimens. The predictive performance of the developed model is assessed by simulating experimental tests reported in the literature.

An efficient nanofiltration system containing mixture of rice husk ash and Fe/CeO2–SiO2 nanocomposite for the removal of azo dye and pesticide

Abstract Fe/CeO2–SiO2 nanocomposite was synthesized by using zwitterionic surfactant 3-(N,N-dimethyloctadecylammonio) propane sulfonate (SB3-18) by sol–gel and hydrothermal methods. The nanocomposite was well characterized before its use. X-ray diffraction (XRD) results confirmed the synthesis of the Fe/CeO2–SiO2 nanocomposite. Crystallite size calculated by using Scherrer equation was 5.33 nm while it was found 5.26 nm by Williamson–Hall equation. Bandgap of Fe/CeO2–SiO2 nanocomposite shows redshift after the doping of Fe. Degradation studies of methylene blue (MB) and chlorpyrifos (CP) were investigated by nanofiltration (NF) column under visible light irradiation. Degradation and adsorption of MB was investigated by three different types of columns under visible light irradiation. It was observed to achieve 100 % removal of MB and 91 % of CP through column in which rice husk ash (RHA) slurry was mixed with the nanocomposite.

Local–overall interactive buckling behaviour of 800 MPa high-strength steel welded H-section members under axial compression

In this study, three different types of columns (i.e. columns with a low width-to-thickness ratio of the plates, columns with a high height-to-thickness ratio of the web, and columns with a high width-to-thickness ratio of the flange) are designed to investigate the buckling behaviour of welded H-section columns fabricated from 800 MPa high-strength steel (HSS). Different buckling behaviours are established, including the load–axial displacement curves, relationships between the local out-of-plane displacement and overall lateral displacement, and ultimate loads of the columns. Current specifications, such as ANSI/AISC and Eurocode 3, are evaluated using the experimental results of this study. It is concluded that ANSI/AISC and Eurocode 3 slightly underestimate the ultimate load of 800 MPa HSS welded H-section members under axial compression. Numerical analyses are performed to estimate the buckling behaviours of 800 MPa HSS welded H-section members under axial compression, and the model is verified using the experimental results in this study. The effects of several parameters (i.e. the slenderness ratio, width-to-thickness ratio of the flange, and height-to-thickness ratio of the web) on the buckling behaviour are investigated. Finite element analyses are carried out for 94 different models, and a more accurate model for estimating the ultimate load of welded H-section members fabricated from 800 MPa HSS is developed. Existing experimental data for HSS columns are collected, and reliability analyses are performed for ANSI/AISC, Eurocode 3, and the proposed model.

Semi-Continuous Adsorption Processes with Multi-Walled Carbon Nanotubes for the Treatment of Water Contaminated by an Organic Textile Dye

Adsorbent columns, containing different amounts of multi-walled carbon nanotubes (MWCNTs), in a semicontinuous process were studied. The optimal conditions for the discoloration of water contaminated by an azoic organic textile dye were investigated. In particular, as representative of contaminated water, a highly concentrated solution of Reactive Black 5 (RB5) equal to 37 mg/L was utilized. A predetermined volume of dye solution, equal to 100 mL, was subjected to repeated cycles of adsorption until the eluted solution became colorless. This adsorption operation was carried out for different types of columns. Adsorbent performances as a function of characteristics of each column were investigated. For each column, the optimum quantity of MWCNTs, maximum volume of treatable solution, carbon usage rate (CUR), empty bed contact time (EBCT), and adsorption capacity were determined. The permeate was characterized by UV-VIS analysis and TOC analysis, while adsorbent material (MWCNTs) was characterized by thermogravimetric TG-DTA analysis. The column containing 2.5 g of carbon nanotubes was revealed to be the best one for the total amount of Reactive Black 5 adsorbed, i.e., 55 mg/g(MWCNTs) The research has shown the high adsorption efficiency of carbon nanotubes toward RB5 dye, highlighting the degradation of the dye molecule and the stratification, inside the columns, of the adsorbed compound.

Reliability considerations of modern design codes for CFST columns

Concrete filled steel tubular (CFST) columns have been increasingly used in tall buildings and bridges due to offering excellent structural and economic benefits. Current design codes for such columns exhibit certain limits in terms of material strengths and section slenderness. This paper aims to evaluate the reliability and the applicability of the current design equations in American code AISC 360–16, European code EC 4 and Australian/New Zealand code ASNZS 2327 for the design of the columns beyond their material and slenderness limits. A comprehensive database with over 3200 tests was collected to develop the statistics of the model errors for different types of columns. Monte Carlo and subset simulation techniques were developed based on Markov Chain Monte Carlo algorithms, to accurately and efficiently predict the reliability index of structures with small failure probability because they account for all uncertainties in material and geometric properties, loads and model errors. The results from the reliability analysis indicate that the reliability index of the concentric column designed by three considered codes is much higher than that of the eccentric column (i.e. beam-column). The results from a parametric study suggest that all three codes can be safely extended to the design of columns beyond the current material and section slenderness code limits.

Point Cloud Semantic Segmentation Using a Deep Learning Framework for Cultural Heritage

In the Digital Cultural Heritage (DCH) domain, the semantic segmentation of 3D Point Clouds with Deep Learning (DL) techniques can help to recognize historical architectural elements, at an adequate level of detail, and thus speed up the process of modeling of historical buildings for developing BIM models from survey data, referred to as HBIM (Historical Building Information Modeling). In this paper, we propose a DL framework for Point Cloud segmentation, which employs an improved DGCNN (Dynamic Graph Convolutional Neural Network) by adding meaningful features such as normal and colour. The approach has been applied to a newly collected DCH Dataset which is publicy available: ArCH (Architectural Cultural Heritage) Dataset. This dataset comprises 11 labeled points clouds, derived from the union of several single scans or from the integration of the latter with photogrammetric surveys. The involved scenes are both indoor and outdoor, with churches, chapels, cloisters, porticoes and loggias covered by a variety of vaults and beared by many different types of columns. They belong to different historical periods and different styles, in order to make the dataset the least possible uniform and homogeneous (in the repetition of the architectural elements) and the results as general as possible. The experiments yield high accuracy, demonstrating the effectiveness and suitability of the proposed approach.

Step-by-step optimization of the HILIC method for simultaneous determinationof abacavir, lamivudine, and zidovudine from dosage form

Combined therapy for HIV treatment shows superior efficacy in comparison to single therapy. Furthermore, the separation and determination of the combined dosage forms hold a significant place in the pharmaceutical industry. Not only reverse phase high-performance liquid chromatography (HPLC) but also hydrophilic interaction liquid chromatography (HILIC) can be used for these purposes. Contrary to conventional RP systems, HILIC may be an alternative for the analysis of polar substances. The aim of this study was the step-by-step development of a simple, rapid, and reliable method for the simultaneous determination of antiviral compounds from their marketed formulation (Trizivir). In order to achieve this goal, various mobile phase systems, buffer types, and concentrations were prepared to provide an appropriate separation. Different types of columns were tested to find the best resolution and high efficiency for the studied compounds. The proposed method provided a simple procedure for the simultaneous analysis of abacavir, lamivudine, and zidovudine in their pharmaceutical preparation within approximately 2 min using the conventional HPLC system. The developed method was fully validated according to the International Council for Harmonisation guidelines from the viewpoint of selectivity, sensitivity, precision, accuracy, linearity, limit of detection, and quantification.

How reading in single- and multiple-column types influence our cognitive load: an EEG study

Purpose The impact of different screen-based typography styles on individuals’ cognitive processing of information has not been given much consideration in the literature, though such differences would imply different learning outcomes. This study aims to enrich the current understanding of the impact of reading in single- and multiple-column types on students’ cognitive processing. Design/methodology/approach An electroencephalogram (EEG) was used to record and analyze the brain signals of 27 students while reading from single- and multiple- column layouts. Findings The results showed a significant difference in students’ cognitive load when reading text from different types of columns. All students exerted less processing efforts when text was presented in two-column format, thus experiencing less cognitive load. Originality/value Using EEG, this study examined the neural consequences of reading in single- and multiple-column types on cognitive load during reading. The findings can be used to enrich the current instructional design practices on how different typographical formats facilitate learners’ cognitive performance.

Integrating a Research‐Based Experience in the Biochemistry I Laboratory: From Separation of Colored Compounds to Protein Purification

As part of our CUR Transformations Project work within the Department of Chemistry and Biochemistry, we aimed to create an additional research‐based experience for the Biochemistry I laboratory course. We designed a series of chromatography experiments that focus on careful observation, experimental design, data interpretation, and presentation skills. Students first work with three different types of columns during a two‐week chromatography lab. The first week they work with two mixtures of colored compounds, each mixture contains 3 out of the 5 compounds. These two mixtures are run through gel filtration, anion exchange, and cation exchange columns. Students analyze their observations in week 1 to design a purification scheme for separation of all 5 colored compounds together in one mixture in week 2. After finishing the two‐week lab, students write a paper based on their results in the format of Nature Methods. Following this experiment, students start a 3‐week lab where they design a scheme to separate two unknown colorless proteins in a mixture. They are given the following information: isoelectric points for both proteins, one of the two proteins has a 6x histidine‐tag, and the 260 nm extinction coefficient of the tagged protein. Students then choose a cation exchange, anion exchange, or an affinity column to use for protein separation. Students analyze their chromatography procedure by using the Bradford reagent to detect protein in column fractions, denaturing gel electrophoresis to assess purification and determine molecular weights of the two proteins, and a western blot to verify identity of one of the proteins using an antibody to 6x histidine‐tags. Lastly, students present their results to their peers in week 4.Support or Funding InformationWe would like to acknowledge support for this CUR Transformations project through NSF DUE IUSE grant # 16‐25354.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Pharmaceutical Applications of Gas Chromatography

Gas chromatography is an analytical tool for the separation of compounds in complex mixtures based on the polarity of compounds. Separation is achieved only for compounds that are volatile or that can be made volatile on derivatization of the compound using derivatizing agents. This is one of the widely accepted tools for the separation of compounds because of its simplicity, sensitivity, and effectiveness. The principle of separation of compounds depends on the partitioning behaviour difference between mobile and stationary phase, the sample is carried by a moving gas stream through a tube packed with a finely divided solid or may be coated with a film of a liquid. Different types of columns having a various composition of stationary phase are been used for the separation of different classes of compounds mixture or sample in a suitable solvent is introduced through the injector maintained at higher temperature which is capable of volatilizing the compound into the column.

Castellated cruciform steel columns

PurposeThe main function of the castellation process is making I-sections stiffer by increasing the height of web and supplying a higher moment capacity of primary axis than plain-webbed members of the same weight. In addition, it optimizes the use of heavy, costly constructional steel material and provides good services accessibility. The purpose of this study was to investigate the strength and buckling behavior of axially loaded castellated cruciform steel columns using finite element analysis. Although a significant body of research exists on the failure of different columns, there is no proper criterion introduced to determine the point of buckling in the equilibrium path of an imperfect column.Design/methodology/approachThis paper considers a wide range of practical geometric dimensions and various end conditions using ANSYS software. Findings are reported for about 224 samples of castellated cruciform I-shaped sections, and a simplified approach to evaluate buckling capacity of castellated columns, using the slenderness-load curve, is developed. In addition, the axial compressive capacities of those steel sections are investigated numerically in the current study.FindingsThe results of nonlinear analyses of these columns revealed that the load-carrying capacity of castellated cruciform steel columns far outweighs and is more appropriate than that of the traditional cruciform steel columns. In the present paper, new geometric criteria have been introduced having the ability to cover different types of columns. It shows the critical load of columns in the range of elastic and inelastic behavior.Practical implicationsThis study can provide a background for practical engineering applications and design specifications for steel structures with castellated sections. In the present paper, new geometric criteria have been introduced having the ability to cover different types of columns. It shows the critical load of columns showing both elastic and inelastic behavior. Because this method showed reliable performance, it can be used during experimental tests for detecting buckling point.Originality/valueThis study can provide background for practical engineering applications and design specifications for steel structures with castellated sections; also, a physical criterion has been defined for calculating the buckling load of real columns.

Phenol Biodegradation by Pseudomonas putida in an Airlift Reactor: Assessment of Kinetic, Hydrodynamic, and Mass Transfer Parameters

An airlift biofilm reactor was employed to study phenol biodegradation by Pseudomonas putida. Hydrodynamic tests were also conducted in a conventional column to facilitate the comparison of the dynamic behavior in different types of columns. The three-phase airlift column offered better aeration than the conventional column as liquid and solid circulation in the downcomer favored bubble breakup, increasing oxygen dissolved in the liquid phase and favoring the phenol biodegradation process. Kinetic parameters of phenol biodegradation by P. putida were obtained in an agitated batch reactor, with the initial phenol concentration varying from 10 to 750 mg/L. Experimental data were fitted using different microbial growth models found in literature. The Yano and Koga model, which considers the formation of multiple inactive enzyme–substrate complexes, fitted well with our experimental data, with a correlation coefficient, R 2 = 0.952. An internal loop airlift bioreactor was used for aerobic phenol biodegradation in which polystyrene particles were utilized to support biomass immobilization. Several tests were performed by varying the influent phenol concentration, hydraulic retention time, upstream flow, and superficial air velocity. It was concluded that until an influent phenol concentration of approximately 300 mg/L, phenol acted as the limiting substrate. For higher phenol concentrations, oxygen became the limiting substrate. An increase in the oxygen concentration resulted in the complete consumption of phenol under high phenol concentration of 500 mg/L.

Concentration at the Minimum Bubble Velocity (CMV) for Various Types of Flotation Frothers

This paper presents the determination of a concentration at the minimum bubble velocity (CMV) for different types of frothers, such as straight and branched alkyl chain aliphatic alcohols, 1,ω-diols, poly(propylene glycol) and poly(ethylene glycol) alkyl ethers, n-alkyltrimethylammonium bromides, commercial frothers and others. The values of terminal rise bubble velocity were reviewed from the experimental data published in the literature for two different types of columns, i.e., a short PAS (used in Polish Academy of Sciences) of height (35 cm) and a long McGill of height (350 cm). The obtained empirical equation is universal and allows one to rapidly and accurately determine the CMV for all surfactants. The proposed empirical model can also be used to predict the terminal bubble velocity–frother concentration curve by knowing the maximum and minimum terminal velocities, as well as the values of CMV. Assessment and usefulness of frother characterization parameters (i.e., concentration at the minimum bubble velocity (CMV), dynamic frothability index (DFI) and critical coalescence concentration (CCC)) were shown in the flotation of coal.

Compressive Behavior of Concrete Confined by Hemp Fiber Composite Jackets

This paper presents an experimental study on the strengthening of small scaled concrete columns externally confined with hemp fiber composite jackets. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study, two different types of columns i.e. circular and square were casted and tested under axial compression. The hemp fiber composite jacket of different thicknesses i.e. 2 and 4 layers were applied using epoxy resin. The test result show that hemp fiber composite jackets are very effective to enhance compressive strength and deformability of the confined concrete. There is found increase in ultimate load carrying capacity with an increase in the jacket thickness. The efficiency of hemp fiber composite jackets is found higher for circular columns then square columns.

Case Study: Designing a 40 Storey High Office Building Using two Variants, with Regular Concrete Columns and with Compound Ultra-High Performance Concrete Columns and Regular Concrete Columns

Abstract The problem of having less and less space and of shortening distances results in urban agglomerations on small surfaces of land. Therefore, it is obvious that the future is that of very high, slender buildings, with unusual and daring shapes. These structures incorporate new and ever more efficient materials, faster lifts, more and more complex design methods and special execution technologies. Globally, there a real competition between developed economies for obtaining the record of having the tallest building on earth. Because columns are an essential component of these high structures, the addressed subject is of global interest. The design of a 40 storey office building is being proposed, using two variants, namely having two different types of columns: simple section – regular columns made of regular concrete (RC) class C 35/45 and compound section – columns with the core made of ultra-high performance concrete (UHPC) and an outer shell made of regular concrete (RC) also class C 35/45. The differences in economy and section between the two proposed variants will be analysed.

Evaluation of a new wide-pore superficially porous material with carbon core and nanodiamond-polymer shell for the separation of proteins

In this study, reversed phase liquid chromatographic columns packed with superficially porous material made of a carbon core and nanodiamond-polymer shell were evaluated for the analytical characterization of proteins. The emphasis was put on the impact of pore size on the kinetic performance when analyzing large molecules. Three different types of columns possessing an average pore size of 120, 180, and 250Å were thus evaluated. As expected, the peak capacities were improved with the 180 and above all the 250Å pore size, while the kinetic performance achieved with the 120Å were systematically lower.It was also shown that a trifluoroacetic acid (TFA) concentration of 0.3–0.5% was required when analyzing proteins, to achieve suitable peak shapes (limited broadening and tailing) with this material. Elevated temperature (>60°C) is mandatory when analyzing proteins with silica-based stationary phases, but this was not the case with this particular column made with a carbon core and nanodiamond-polymer shell, since the peak capacities were not improved at high temperature. However, there was a need to increase mobile phase temperature in the range 70–90°C when analyzing monoclonal antibodies (mAbs), to limit adsorption that often occur in RPLC with this specific class of biomolecules.Finally, the FLARE® wide-pore column was applied to real life samples of native, oxidative stressed and reduced therapeutic proteins as well as reduced, digested mAbs and antibody drug conjugates (ADCs), to highlight the possibilities offered by this column technology.