Column Material Research Articles

Experimental investigation into mild steel circular concrete-filled double skin steel tube columns

Constructing the concrete-filled double skin steel tube (CFDST) column involves placing concrete in between two steel tubes. Such tubes may have the same cross-section shape on the inside and outside, or they may have different cross-section shapes, as in the case of a square outer tube and a square inner tube, a circular outer tube, and a square inner tube, or a square outer tube and a circular inner tube, etc. In this article, the response of concrete-filled double-skinned steel tube columns (CFDST) to axial load is experimentally investigated. To create the CFDST column, two concentric mild steel circular tubes were filled with concrete. CFDST column behavior was illustrated using typical curves of axial load vs deformation and axial load versus longitudinal strain in the outer steel tube, inner steel tube, and concrete core. To further explore how changing the column's geometry and materials can affect its ultimate strength, parametric research was carried out. In the end, the experimental results were compared to the requirements specified in codes like Eurocode-4, AISC-360, ACI, and the equation given by Han et al. (2009).

Numerical Study on the Deformation Behavior of Geosynthetic-Encased Stone Columns Supporting Embankments

The method of encasing the stone column with a proper type of geosynthetic material is a widely used technique to provide the required lateral confinement and to avoid the dispersion of granular column material into soft clay. Along with the improved ultimate load capacity and the reduced settlement and bulging, the geosynthetic encasement preserves the easy drainage ability of stone columns. This paper presents the finite element analysis results of a hypothetical embankment on a soft soil deposit which is improved by geotextile encased stone columns and geogrid reinforced sand mat on top. At first, numerical results of three dimensional (3D) finite element model (FEM) were validated via the experimental data of previous field studies. Afterward, parametric studies were carried out on the FEM considering the effect of the sand mat thickness, the stiffness of the geosynthetic reinforcement, and the geosynthetic encasing length and encasement stiffness on both the horizontal and vertical deformation of stone columns. Settlement differences between columns and soft soil in both the short term and long term were also determined. The optimum values of sand mat layer thickness, vertical encasement length, and geosynthetic stiffness are recommended to be used for preliminary designs.

Removal of Nitrogen and Phosphorus from Wastewater Using Layered Filter Media

After biological wastewater treatment, ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), and phosphate phosphorus (PO4-P) remain in the effluent, which is discharged into natural water bodies. For further removal of these wastewater compounds, three selected materials were used as filter media: quartz sand used in drinking water treatment plants, Purolite A502PS resin, and natural zeolite. After placing all selected materials in the first filtration column (height of each layer-30 cm), the concentration of NH4-N in the wastewater was reduced by 5 times (from 8.22 to 1.5 mg/L), the concentration of NO3-N by 6 times (from 2.46 to 0.44 mg/L), and the concentration of PO4-P by 3 times (from 1.56 to 0.45 mg/L). The second column was without a Purolite A502PS layer, so the concentration of NO3-N in the filtrate from the second column was not reduced. The filtration columns were operated for about 2 months, and the filtration was stopped due to clogging with suspended solids (TSS) with an average concentration of 53.2 mg/L. The preliminary removal of TSS from wastewater before filtration through sorbents is recommended. The tested materials effectively treat wastewater of nitrogen (average efficiency 80–83%) or phosphorus (average efficiency 65–67%) and do not pollute the wastewater with environmentally hazardous substances, so they can be used in the development of tertiary wastewater treatment filters.

Comparison between the use of polyether ether ketone and stainless steel columns for ultrasonic-assisted extraction under various ultrasonic conditions

The ultrasound-assisted extraction (UAE) was conducted using the stainless steel (SS) and polyether ether ketone (PEEK) columns and analyzed with high-performance liquid chromatography (HPLC) to understand the mechanism of ultrasound-assisted chromatography (UAC). Empty SS and PEEK columns were used to extract dyes from a fabric under identical conditions with several parameters including the initial ultrasonic bath temperatures (30 °C and 40 °C), ultrasound power intensities (0, 20, 40, 60, 80, and 100 %), ultrasound operation modes (normal and sweep), and ultrasound frequencies (25 kHz, 40 kHz, and 132 kHz) to compare their extraction capabilities. After 30 min of extraction, the amount of extract was determined by HPLC. The PEEK material was significantly affected by ultrasonic radiation compared to the SS material, especially at a higher temperature (40 °C), power intensity (100 %), and frequency (132 kHz) with sweep mode. At a maximum power density of 45 W/L, the extraction effectiveness ratio of PEEK to SS was in the range of 1.8 - 3.9 depending on the specific frequency, initial temperature, and with or without temperature control. The most optimal ultrasound frequencies, in terms of enhancing extraction effectiveness, are in the order of 132 kHz, 40 kHz, and 25 kHz. Unlike the SS material, the PEEK material was more affected by temperature and acoustic effects under identical conditions, especially at 132 kHz ultrasound frequency. In contrast, at lower frequencies of 40 kHz and 25 kHz, no significant differences in the acoustic effects were observed between the PEEK and SS materials. The findings of this study contribute to elucidating the roles of column materials in UAE and UAC.

EVALUATION OF THE PERFORMANCE OF PACKED BED COLUMN FOR HEAVY METAL ION REMOVAL USING RICE HUSK POWDER COATED WITH IRON OXIDE NANO-PARTICLES

<p>The packed bed column study investigated the removal of toxic metal ions (Cr, Pb & Zn) using rice husk coated with iron oxide nanoparticles as an adsorbent material. The chemical fusion process prepared the nanomaterial adsorbent, and iron oxide capping provides stability to the prepared nano adsorbent. The characteristics of prepared nano adsorbents and their stability were examined by SEM/EDX, VSM, XRD, Zeta Potential, TGA & DTA methods. Breakthrough curves confirm the ability to obtain the maximum adsorption under operating conditions of 5, 7.5 & 10 - cm bed heights, 100, 200 & 300 – mg/L of metal ion concentrations and 5, 7.5 & 10 – mL/min of inflow rate of the solutions into the column. The ANOVA & CCD analysis confirms the linearity of actual and predicted values of the amount of adsorption process. Thomas and BDST model studies show the best fit to the regression values for obtaining earlier breakthroughs in the fixed bed column. At the pH of 2.0, the maximum amount of heavy metals adsorption was observed. The maximum desorption rate of the column and adsorbent material was obtained by adding 0.3 N of H2SO4 at 40 minutes average time for all the three metal ions.</p>

Functionalized monolithic columns: Recent advancements and their applications for high-efficiency separation and enrichment in food and medicine.

The chromatographic column is the core of a high-performance liquid chromatography (HPLC) system, and must have excellent separation efficiency and selectivity. Therefore, functional modification materials for monolithic columns have been rapidly developed. This study is a systematic review of the recently reported functionalized monolithic columns. In particular, the study reviews the types of functional monomers under different modification conditions, as well as the separation and detection techniques combined with chromatography, and their development prospects. In addition, the applications of functionalized monolithic columns in food analysis, biomedicine, and the analysis of active ingredient of Chinese herbal medicines in recent years are also discussed. Also reviewed are the functionalized monolithic columns for qualitative and quantitative analysis. It provided a reference for further development and application of organic polymer monolithic columns.

Stability and Rupture of Liquid Crystal Bridges under Microgravity

Liquid-crystal columns were prepared and observed under microgravity aboard suborbital TEXUS rocket flights. The microgravity phase of each flight lasted for approximately six minutes. We tested structures in different liquid-crystalline mesophases. In the isotropic and nematic phases, the Rayleigh-Plateau instability led to the collapse of the columns. However, in the smectic A and C mesophases, it was found that the columns survived the extension to slenderness ratios (length/diameter) of over 4.5 (and in one case, more than 6). The liquid-crystalline material in the millimeter-sized columns was macroscopically disordered. Thus, regular shell-like internal layer structures that stabilized the columns can be excluded. Instead, the reason for their persistence was the yield stress of the material, which is quite different for the different mesophases. In the columnar mesophase, the cylindrical bridge even survived the strong deceleration when the rocket re-entered the atmosphere. During the breakup of the filaments, the neck thinning dynamics were determined.

Sustainable utilisation of steel slag as granular column for ground improvement in geotechnical projects

Granular column is an attractive mitigation method which is widely used in geotechnical engineering to enhance the bearing capacity, reduce settlement and accelerate consolidation. Utilisation of industrial wastes such as steel slag in soil stabilization can be an environment-friendly and cost-effective extraction technique to the disposal of solid waste materials. Previous studies investigated the bearing capacity and settlement of ground improved with granular columns with or without the geosynthetic encasement. However, very limited number of studies have investigated the response of ordinary stone columns without encasement and geosynthetic encased steel slag columns under lateral loading. In this paper, the lateral load capacity of steel slag granular column-soil composites has been investigated. For this purpose, a series of large direct shear tests were performed on the column-soil composites with the steel slag column and the ordinary stone column with or without the geosynthetic encasement. The effect of type of column materials (steel slag and sand), column diameter, number of columns, columns arrangement, and geosynthetic encasement on the shear strength parameters of column-soil composites have been studied. The experimental results show the effectiveness of using the steel slag columns to improve the lateral load-bearing performance of soil.

Variation of satellite-derived total suspended matter in large lakes with four types of water storage across the Tibetan Plateau, China

Total suspended matter (TSM), as an indicator of the concentration of fine materials in the water column including particulate nutrients, pollutants, and heavy metals, is widely used to monitor aquatic ecosystems. However, the long-term spatiotemporal variations of TSM in lakes across the Tibetan Plateau (TP) and their response to environmental factors are rarely explored. Accordingly, taking advantage of the Landsat top-of-atmosphere reflectance and in-situ data, an empirical model (R2 = 0.83, RMSE = 1.08 mg/L, and MAPE = 19.49 %) was developed to estimate the average autumnal TSM in large TP lakes (≥50 km2) during the 1990–2020 period. For analyzing the spatiotemporal variability in TP lakes TSM, the examined lakes were classified into four types (Type A-D) based on their water storage changing in different periods. The results showed that the lakes in the southern and some northeastern parts of the TP exhibited lower TSM values than those situated in other regions. The assessment of TSM in each of these four lake types showed that more than half of them had a TSM value of <20 mg/L. Apart from Type D, the lakes with the TSM showing significantly decreasing trends were dominantly Types A-C. A relative contribution analysis involving five driving factors indicated that they contributed by >50 % to lake TSM interannual variation in 73 out of 114 watersheds, and the lakes area change demonstrated the greatest contribution (82.2 %), followed by wind speed (11.0 %). Further comparison between the entire lake and the non-expansive regions suggested that the expansive region played an indispensable role in determining the TSM value of the whole lake. This study can help to better understand the water quality condition and provide valuable information for policy-makers to maintain sustainable development in the TP region.

Tests of circular geopolymer concrete-filled steel columns under ambient and fire conditions

Sixteen circular geopolymer concrete-filled steel tubular (GCFST) columns made with carbon steel were tested at ambient temperature to obtain the axial load-moment interaction curves and buckling curves. Moreover, six circular composite specimens with stainless steel tubes were tested in fire to study the effects of concrete type and presence of internal reinforcement on the fire resistance. It was observed that the provisions in the Australian standard AS/NZS 2327 for composite columns can satisfactorily predict the ambient temperature strength of GCFST columns. From the fire tests, it was found that the use of geopolymer concrete could significantly improve the fire resistance of composite columns compared with the conventional counterpart made with ordinary Portland cement concrete. The results indicate that it is possible to eliminate the internal steel reinforcement or external fire protection to achieve required fire resistance by using high performance materials in composite columns. A life cycle analysis was further conducted, which showed that the life cycle cost of GCFST columns made with carbon steel was similar to that of the conventional counterparts, but the embodied carbon of the former was approximately 13.6 to 20.8% less than that of the latter.

Preparation of Modified Porous Polyionic Liquid Microspheres and Their Application in High Performance Liquid Chromatography

Polymer microspheres have been widely used as a stationary phase in liquid chromatography. We characterized the properties of the novel polyionic liquid microspheres prepared and explored their application as a stationary phase in liquid chromatography. Cytosine, uracil, benzene, benzene homologs and alkaloids were successfully separated by liquid chromatography with the polymer microspheres as packing materials in the chromatographic column.

Finite Element Modelling Of An Embankment Seated On Pervious Concrete-Stone Composite Column

Embankments rested on soft soils reinforced with stone columns cannot provide enough support. In such soils, to increase their bearing capacity, pervious concrete can be applied to upper portion of the stone column forms a composite column to restrain bulging collapse. Pervious concrete is a type of concrete made without adding fine aggregate and having permeability comparable with stone column materials. The current research work carried out to study the behaviour of embankment rested on composite column through a parametric study using finite element analysis. The parameters; soft clay elastic modulus, embankment fill elastic modulus, stone column material elastic modulus, pervious concrete column elastic modulus, spacing of column, length of pervious concrete column in composite column, permeability of soft clay, and construction rate are considered for the parametric study. The influence of these parameters are compared and rated in terms of the degree of importance.

Improvement of As(V) Adsorption by Reduction of Granular to Micro-Sized Ferric Hydroxide

The remediation of groundwater containing arsenic is a problem that has been addressed using adsorption processes with granulated materials in columns, but the remediation itself could be improved by using micro-sized adsorbents in stirred systems. In this study, arsenate (As(V)) batch adsorption experiments were performed using granular ferric hydroxide (GFH) and two derived micro-sized materials. Reduced-size adsorbents were produced by energetic ball milling, giving final sizes of 0.1–2 µm (OF-M samples) and ultra-sonication, producing final sizes of 2–50 µm (OF-U samples). Equilibrium isotherm studies showed that the Langmuir model was a good fit for the three sorbents, with the highest maximum adsorption capacity (qmax) for OF-U and the lowest for OF-M. The adsorption of the two groundwater samples occurred according to the obtained equilibrium isotherms and indicated the absence of interfering agents for the three adsorbents. Batch kinetics tests in stirred beakers followed a pseudo second-order model and indicated that the kinetics of the OF-U sorbent was faster than the kinetics of the GFH sorbent. The tests also showed an increase in the qe values for the reduced-size sorbent. The application of ultrasonication to the GFH produced an increase of 23 % in the qmax and b term and an increase of 34-fold for the kinetic constant (k2) in the stirred batch systems tested. These results suggest that this new approach, based on ultra-sonication, has the potential for improving the adsorption of arsenic in groundwater.

EFFECTIVENESS OF THE USE OF MULTIMEDIA-BASED LEARNING MEDIA IN BUILDING CONSTRUCTION COURSES

This research aims to find out the effectiveness of the use of multimedia-based learning media in building construction courses I. The research method used is quasi experimental with a randomized form of pretest-posttest control group design. Data collection is done with pretest and posttest instruments given to two classes of experiments and controls. The results of this study are derived from the Whitney U-Mann test and the N-gain test, which showed that there was a significant difference between the results of the experimental class learning and the control class, and there was an increase in learning outcomes with intervals of 56%-76% in column material, plate material, window door sill material, ladder material, and roofing materials. As a result, the use of multimedia learning materials in these materials is effective for online learning in building construction courses.

Front Cover: Comparison of the separation of proteins of wide‐ranging molecular weight via trilobal polypropylene capillary‐channeled polymer fiber, commercial superficiously porous, and commercial size exclusion columns

DOI: 10.1002/jssc.202100891 The reversed-phase (RP) separation of proteins, without size-exclusion contributions, is affected on capillary-channeled polymer (C-CP) fiber stationary phases. Polyester C-CP fibers are demonstrated to perform the rapid RP separation of peptides and proteins ranging in molecule weight of 1.44-to-660 kDa. Comparisons with commercial RP superficially porous and size exclusion columns designed for protein separations show that the across-the-board separation quality realized by the fibers is superior to the other column formats, with column material costs being far less than the standard columns.

Highly selective extraction of uranium from wastewater using amine-bridged diacetamide-functionalized silica

A major environmental concern related to nuclear energy is wastewater contaminated with uranium, thus necessitating the development of pollutant-reducing materials with efficiency and effectiveness. Herein, highly selective mesoporous silicas functionalized with amine-bridged diacetamide ligands SBA-15-ABDMA were prepared. Different spectroscopy techniques were used to probe the chemical environment and reactivity of the chelating ligands before and after sorption. The results showed that the functionalized SBA-15-ABDMA had a strong affinity for uranium at low pH (pH = 3) with desirable sorption capacity (68.82 mg/g) and good reusability (> 5). It showed excellent separation performance with a high distribution coefficient (Kd,U > 105 mL/g) and separation factors SFU/Ln > 1000 at a pH of 3.5 in the presence of lanthanide nuclides, alkaline earth metal and transition metal ions. In particular, SiO2spheres-ABDMA was used as a column material, which achieved excellent recovery of U(VI) (> 98%) and good reusability for samples of simulated mining and nuclear industries wastewater. XPS and crystallography studies clearly illustrated the tridentate coordination mode of U(VI)/PEABDMA and the mechanism and origin behind the high selectivity for U.

Optimal allocation of material and slenderness limits for the rectangular concrete-filled columns

The current American Specification AISC 360–16 for concrete-filled steel tubular (CFT) columns exhibits particular limits in terms of section slenderness and material strengths. This paper proposes a decision tree algorithm, together with a comprehensive compiled experimental database of rectangular CFT columns under concentric loading and reliability analysis, to establish new optimal limits for section slenderness and material strength. The decision tree analysis yielded “data-driven classification rules” indicating that a relative section slenderness of 5, concrete compressive strength of 175 MPa, and steel yield strength of 850 MPa are considered optimal limits for the design equations in the AISC 360–16 in terms of achieving the minimum reliability requirements. The reliability analysis results are used to run a sensitivity analysis on the CFT columns to identify the dominant parameters that affect their axial loading capacity. Based on the sensitivity results, special attention should be given to the variability of concrete strength. The last part of this study demonstrates that the design equation of the high-strength CFT member in the new AISC Specification (AISC 360–22; obtained from a public review draft) can be extended to the conventional materials using the same proposed optimal limits.

Axial compressive behaviour of CFST column externally reinforced by CFRP strips – A design of experiments approach

The purpose of this research is to investigate the influence of CFRP strips wrapping scheme (partial wrapping) in strengthening of CFST column subjected to axial compression. To complete the experimental investigation in an economical way, the central composite design (CCD) of the response surface methodology (RSM) was used to design the experiments. Based on the CCD experimental model, 9 unique tests were performed and the failure mode of the specimens, load–deformation behaviour, ultimate strength and ductility behaviour were studied. The test results showed that externally bonding CFRP strips is an effective approach to restraining axial deformation and enhancing the ultimate capacity of the column under compression. By bonding three layers of CFRP strips, the deformation of the columns was restricted to a maximum of 55.78% and 50.27% compared to the column bonded with one layer, when set at spacings of 20 mm and 30 mm, respectively. The ANOVA, Pareto chart and contour plot of RSM revealed that the layers of the CFRP wrapping scheme was more significant than the strips spacing in increasing the strength capacity of the CFST column. The suitability of design models proposed in various literatures for predicting the strength capacities of CFST columns strengthened with CFRP wrapping scheme was also examined. A simple design model, derived considering the column geometry and material strength of column and CFRP composites, was proposed to predict the axial strength capacities of CFST short columns confined by CFRP strips by using regression analysis. The proposed design model provides a more accurate and reasonably stable prediction compared with other existing design models.

The Novel Polymethacrylate Based Hydrophilic Stationary Phase for Ion Chromatography.

Ion chromatography is widely used as a useful and powerful tool for the analysis of anionic and cationic components found in waters and aqueous media. The performance and selectivity of ion chromatography are based on the stationary phase column packed material. In this study, it is aimed to develop new column material with quaternary ammonium functional group based on monodisperse polymeric particles for ion chromatography and to investigate their chromatographic performance. For the analysis of inorganic anions by ion chromatography, new stationary phases macroporous monodisperse particles based on 3-chloro-2-hydroxy propylmethacrylate-co-ethylene dimethacrylate are obtained as column packing material. 3-chloro-2-hydroxy propylmethacrylate and ethylene glycol dimethacrylate are transformed to porous monodisperse particle form by using glycidyl methacrylate as the seed latex and ethyl benzene as the porogen solvent via micro-suspension polymerization technique. Then macroporous monodisperse particles surface is functionalized by triethylamine so strong anion exchange is obtained for ion chromatography packing material. A series of stationary phases prepared from polymer particles containing different amounts of porogen solvent were tested. The results show that column packing material is successful to separate inorganic anions mixture such as F-, Cl-, NO2-, Br-, NO3- by using the carbonate and bicarbonate solutions as mobile phases.

Suitability Analysis of Stone Column Materials with PLAXIS

Stone columns are usually provided in groups to support various geotechnical structures, such as embankments, storage tanks, etc. Several experimental and numerical studies have been performed to study the response of stone columns as soil reinforcement. For relatively moderate loading of a structure, application of stone columns either singly or in groups is widely used. The enhancement of strength of the soil is governed by the type of original subsoil and the properties of the coarse aggregate materials used for the stone columns. Several researchers have analyzed different coarse-grained materials using various plane strain approaches to model the stone columns. This article deals with the non-linear analysis of an isolated stone column embedded in a semi-infinite medium of sandy soil. The parameters which crucially affect the settlement characteristics and the bulging failure of stone columns have been determined. The suitabilities of two different natural aggregates, pebble gravels, and crushed pebble gravels as materials for the stone column have been compared on the basis of their settlement behavior using 2D numerical modeling with the PLAXIS software.