Types Of Columns Research Articles

Quantum Sieving Effects of Ni(bdc)(ted)0.5 and Effective Separation Performance of Ni(bdc)(ted)0.5@γ‐Al2O3 for H2/D2

AbstractThe MOF Ni(bdc)(ted)0.5 was selected as the hydrogen isotope separation material in this paper and the separation mechanism of this material was investigated by molecular simulation. Theoretical calculations proved that Ni(bdc)(ted)0.5 had chemical affinity quantum sieving (CAQS) effect and kinetic quantum sieving (KQS) effect. Because the adsorption capacity of D2 in Ni(bdc)(ted)0.5 was larger than H2 and the diffusion rate was smaller than H2 at 77 K, Ni(bdc)(ted)0.5 could realize the separation of hydrogen and deuterium in gas chromatography. Ni(bdc)(ted)0.5@γ‐Al2O3 composite was prepared by liquid phase epitaxy method as gas chromatographic packings (column type: 0.6 m×2.0 mm I.D.) to investigate the separation performance of H2/D2 at 77 K. Under the optimal chromatographic conditions, the retention time of H2 and D2 were 1.95 and 3.48 min respectively and the resolution (R) was 2.12, indicating that the separation of H2 and D2 could be realized efficiently and quickly by using Ni(bdc)(ted)0.5@γ‐Al2O3.

Development, Optimization, and Validation of a Novel HPLC Method for Simultaneous Quantification of Artesunate and Amodiaquine in Tablet Formulations

Artemisinin-based combination therapy (ACTs) has become the primary first-line treatment for mild falciparum malaria in the majority of African countries. A fixed-dose combination of amodiaquine and artesunate is commonly employed to enhance treatment compliance and achieve successful malaria outcomes. In this study, a specific, accurate, linear, precise, and repeatable method was optimized, verified, and applied for the simultaneous estimation of artesunate and amodiaquine HCl in a commercially available artesunate-amodiaquine tablet with a dosage of 100 mg/270 mg. The optimization process involved two steps. Firstly, the top three were carefully selected out of seven characteristics influencing the separation. These key elements required fine-tuning, namely the column type, ion pair, and the residual amount of acetonitrile (ACN) remaining after elution. In the second step, a Box-Behnken experimental design, coupled with Derrenguer's desirability approach, was utilized to identify the ideal target conditions. The optimized method demonstrated excellent specificity, accuracy, linearity, precision, and repeatability, allowing for the reliable simultaneous estimation of artesunate and amodiaquine HCl in the artesunate-amodiaquine tablet. This method offers a valuable tool for quality control and dosage determination in the pharmaceutical industry. By employing advanced experimental techniques and focusing on critical parameters, the study contributes to analytical methodologies in malaria treatment.

진동수주형 파력발전장치의 발전기 모델을 포함한 통합유동해석 물리모델 개발

This study was conducted to develop a real-time integrated flow analysis physics model including a generator model for an Oscillating Water Column (OWC) type wave power generator. Based on the previously performed chamber-turbine flow analysis physical model, a generator model was added to develop a physical model capable of predicting the rotational speed of the turbine. The generator physical model was implemented using the Kriging metamodel to secure real-time and obtain an interpolation model for predicting nonlinear response. The integrated flow analysis physics model was developed by integrating the flow analysis physics model within the chamber-turbine and the generator meta-model. The rotational speed of the turbine was calculated using the mechanical tote and the electrical torque of the generator model. In this study, in order to verify the integrated flow analysis physical model, the water column height in the OWC used operational data obtained from actual sensors. The air pressure in the OWC chamber and the rotational speed of the turbine obtained by using the integrated flow analysis physical model were able to obtain reasonably reasonable results for implementing a digital physical model in the future.

TEM study of ∼PbCr2S4 columnar misfit phases

The disordered structure of the columnar misfit ​∼ ​PbCr2S4 phase (∼ character indicates that it is close to the stoichiometric composition but slightly away) has been revealed by means of transmission electron microscopy (TEM) varied techniques such as selected area electron diffraction (SAED), high-resolution TEM (HRTEM), dark-field TEM and high-angle annular dark field (HAADF) in scanning-transmision (STEM) mode. The structure consists of a hexagonal framework (Cr21S36), with unit cell parameters a0 ​= ​b0 ​= ​21.407 (1) Å and c0 ​= ​3.476 (1), and with hexagonal (Pb6Cr2S6) and trigonal columns (Pb3S) with the same a and b parameters and different c: c3 ​= ​3.98 Å; c6 ​= ​5.62 ​Å, measured by electron diffraction. While the framework exhibit no crystalline disorder, the arrangement of the two types of columns is disordered. This disorder is shown by electron diffraction as diffuse scattering planes which are perpendicular to the framework c axis and parallel to the a∗b∗ plane. While the disorder between hexagonal columns is due to the lack of correlation between different columns, we observe in the trigonal columns also the presence of intra-columnar atomic disorder. X-ray wavelength dispersive spectroscopy (XWDS) analyses produce Pb0.81(1)Cr2S3.97(6) composition. TEM imaging techniques suggest lack of correlation between trigonal columns as the cause for the observed disorder as well as inside-the-column structural disorder in Pb3S trigonal columns.

Research on the seismic behaviour of hollow prefabricated square column with high-strength reinforcement using UHPC grouting materials

In this study, a hollow prefabricated square column with high-strength reinforcement is developed to realise optimum seismic performance and promote the application of high-performance materials in columns. A column and cap constructed for testing using the ultrahigh-performance concrete grouting material are connected using grouted sleeves. The seismic performance of the proposed column is evaluated by comparing and analysing the responses of the proposed column and that of two other types of columns under cyclic load. Further, the effects of the longitudinal steel bars strength and volume of the hollow part of the column on the seismic performance of the proposed column are studied. The experimental results shown that the configuration of the high-strength reinforcement in the column positively influence its seismic performance. The modification of the reinforcement strength and hollowing rate of the column have some degree of influence on the structural response of the proposed column under cyclic loading, which lay a foundation for optimal design of the structure of the proposed column.

Axial Compression Study of Crash Boxes with Various Honeycomb Structures

In recent times, automotive manufacturing companies are focusing on developing components that is capable of increasing safety features associated with lightweight materials such as using aluminium. One such innovation is providing the vehicle with crash box, which is generally located at the front bumper. The function of the crash box is to safeguard the passenger by absorbing the kinetic energy of collision and self-deformation. In this paper, the authors presented a study of the compressive test applied on crash boxes with different types of honeycomb sandwich circular columns using 3D virtual modelling and finite element (FE) simulation with the help of Solidworks and Ansys Workbench respectively. This sandwich structure comprises two circular aluminium tubes filled with core shaped as a large-cell honeycomb lattice. Here, the crash boxes with three different honeycomb sandwich circular columns i.e., hexagonal, triangular, and semi-circular arrangement, were investigated and the energy absorption capabilities of these columns were studied. FE simulations were used to evaluate maximum stress that a material can sustain over a period under a load, material deformation, geometric changes, and load-displacement results using a constant material property of that of aluminium alloy, and the results of the three different arrangements were compared and it is known that the crash box with semi-circular arrangement has high energy absorbing capacity.

Fabrication process development and basic evaluation of eggshell-based column packing material for reversed-phase preparative separation

Purification of basic drugs in reversed-phase mode is often difficult, mainly due to adsorption of positively charged compounds to the silica gel-based stationary phase. Since this adsorption can be suppressed under alkaline condition, columns with alkali-resistance are required. In addition, compounds with acid-sensitive structures are sometimes degraded during separation on silica gel-based columns which exhibit acidity due to their surface structure. We prepared an alkali-resistant reversed-phase packing material, Eggshell-PMAcO based on eggshells modified with an amphiphilic copolymer, poly(maleic acid-alt-1-octadecene) (PMAcO). The height equivalent to a theoretical plate (HETP) of the Eggshell-PMAcO column was improved by surface treatment with ammonium acetate buffer (900 mM, pH = 3.7), which is an inexpensive reagent, and the retention behavior for hydrophobic compounds was compared to a typical ODS column based on silica gel, resulting in sufficient selectivity of the eggshell-based column for hydrophobic compounds, as indicated by the ratio of retention factors of pentylbenzene and butylbenzene (Eggshell-PMAcO column: 1.55, ODS column: 1.65). Column temperature-dependent retention behavior of naphthalene was investigated in the temperature range from 25 °C to 45 °C, followed by the calculation of thermodynamic parameters. There was little difference in the standard molar enthalpy (Eggshell-PMAcO: −19.6 kJ/mol, ODS: −21.7 kJ/mol). The absolute value of the standard free Gibbs energy for the Eggshell-PMAcO column was much smaller than that of the ODS column (Eggshell-PMAcO: −0.284 kJ/mol, ODS: −13.0 kJ/mol), indicating that the Eggshell-PMAcO column had a weaker retention strength for naphthalene than the ODS column mainly due to the large difference in the standard molar entropy (Eggshell-PMAcO: −64.9 J/mol K, ODS column: −29.2 J/mol K). The retention capacities for imipramine under neutral (water/methanol) and alkaline (0.1% triethylamine water/methanol) conditions were 0.2 mg and 5 mg, respectively, based on injection mass-dependent HETP, retention factor and symmetry factor. Finally, the prepared column was applied to the purification of a building block for nucleic acid drugs. This study demonstrated that reversed-phase columns, which can be fabricated from eggshells and an amphiphilic copolymer in an inexpensive and eco-friendly way, have the ability to purify basic compounds and acid-sensitive compounds.

Finite element and theoretical investigations on PVC–CFRP confined concrete columns under axial compression

This article examines the performance of Carbon Fibre Reinforced Polymer (CFRP) on Concrete Filled with Polymer Vinyl Chloride Tube (CFPT) columns under axial compression. Firstly, 44 CFPT specimens from the literature were analyzed using ABAQUS software to understand the compressive behavior of specimens under applied displacement. Secondly, 268 CFPT specimens are simulated to understand the influence of CFRP on these control specimens with a varying number of FRP layers and wrapping depth. Other variables such as the unconfined concrete strength, the thickness of the PVC tube, and the size and slenderness ratio of the columns were also studied. Studies are extended to confinement damage plasticity model analysis of CFRP-CFPT (CCFPT) columns. Relationships between the load-carrying capacity of CCFPT columns and the CFRP properties were developed. The effect of these parameters on the CFPT leads to the development of analytical models. It is an advantage to applying a such new type of composite columns in various applications.

Effect of Hidden Column Type on Seismic Performance of the Insulated Sandwich Wall Panel Joints with Ceramsite Concrete Layer

Ceramsite concrete, with its advantages such as excellent long-term durability and thermal insulation properties, is suitable to be utilized as precast sandwich wall panels. While the lack of assessment of the seismic performance of such wall panel joints has been studied. Therefore, an experimental program was carried out to investigate and improve the seismic performance of the new type of wall panel joints. The seismic performances of the specimens were experimentally evaluated, including failure mode, loading and deformation capacity, ductility, the strain of vertically distributed steels, stiffness, and energy dissipation. The insulated sandwich wall panel joints have good seismic performance shown by the quasi-static test. The ductility coefficient of all specimens was greater than 3. The structure of the control group specimen presented a better match in stiffness, bearing capacity, ductility, and energy dissipation. The sleeve connection confirmed that the integrity of the joint, and the L-shaped hidden column could improve the ductility coefficient and equivalent viscous damping coefficient by about 4.2%. The results can promote the research of such wallboard system. This design approach of sandwich wall panel joints with lightweight concrete is broadly applicable to the exploration of more types of energy-saving wallboard systems.

Predicting equation of quasi-static and dynamic failures of steel columns under fire

Steel columns may fail in dynamic or quasi-static types under fire. The quasi-static failure of steel column could be considered as gradual column removal in the collapse assessment of structures, while the dynamic failure cannot. Hence, it is meaningful if the failure type of the column could be predicted. To identify the failure types of box-section steel columns under fire simply, this paper adopted a validated numerical model to conduct a systematic parametric analysis. The critical axial restraint stiffness ratio (βl,cr), which is used to predict the failure type of columns under fire conditions, is the main focus. Firstly, the values of βl,cr of columns with a representative section were studied, with various slenderness ratios and load ratios being considered. Then, the effects of width-thickness ratio, length–width ratio, sectional size, and bending moment load ratio on βl,cr were studied. The results indicate that βl,cr of columns with the representative section increases with the rise of the load ratio, and increases sharply after the load ratio exceeds a certain level. Besides, the dynamic effect during column buckling and βl,cr both increase with the rise of either the width-thickness ratio, length–width ratio, or sectional size. Moreover, based on the results, a predicting equation for βl,cr of box-section steel columns was proposed. The failure type of a steel column under fire can be easily predicted by the proposed equation. Finally, the proposed equation was verified by an additional series of case studies, and good agreement was achieved.

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.

Confinement mechanism of FRP-confined concrete-encased cross-shaped steel columns

Fibre-reinforced polymer (FRP)-confined concrete-encased cross-shaped steel columns (FCCSCs) are an emerging type of hybrid columns. In an FCCSC, the concrete is subjected to combined confinement from the steel section and the FRP tube, leading to an enhanced load capacity and excellent ductility of the column. While several recent experimental studies have demonstrated the excellent structural performance of FCCSCs, the complex confinement mechanism behind their structural behaviour has not been clarified or thoroughly examined. This paper presents a comprehensive study aiming to investigate the confinement mechanism of FCCSCs. In this paper, the experimental observations of FCCSCs are first summarized, followed by three-dimensional FE modelling of the columns. The FE models, after being verified against the test results in various aspects, are used for a systematic parametric study. In this study, the complex interaction between the three components of FCCSCs (i.e., FRP tube, steel section and concrete) is illustrated explicitly and the effects of key parameters (i.e., flange width, flange thickness, web thickness and FRP tube thickness) are examined separately and thoroughly, leading to an in-depth understanding of the confinement mechanism of FCCSCs. In particular, through the examination on the distribution of steel flange-to-concrete normal pressure, it is shown quantitatively that the variations of the dimensions of the steel section in a practically wide range have only marginal effects on its confinement to the concrete, while the increase of FRP tube thickness tends to reduce the confinement effect from the steel section.

Facile synthesis of porous DNA/Protein hydrogels for water purification

Porous structured DNA hydrogels with a rapid mass transfer rate constitutes new promising materials for biomedical and environmental applications. However, their biocompatibility can be influenced by the components used to support the structure formation. Here we describe for the first time the use of natural protein stabilized Pickering emulsion as a template for the preparation of porous DNA gel. The results indicated that protein properties including isoelectric point (pI) and size had a great influence on the structure of the DNA gel. Moreover, using bovine serum albumin (BSA) as an example, the morphology and density of the pores in the gel could be well-tuned by the amounts of added proteins. Both CCK-8 and live/dead staining assay showed that the as-prepared gel was highly biocompatible. Considering the intriguing properties, this study demonstrated that the as-prepared gel can be used to prepare columns for efficiently removing multiple pollutants in water via a facile filtration process based on different retention mechanisms, improving the application potential of DNA gel in environmental science. • Facile preparation of biocompatible porous DNA/protein hydrogel was described. • Protein properties greatly influenced the structure of the hydrogel. • The morphology of the pores in the gel can be well tuned by added protein amount. • The gel displayed a high swelling capacity and good biocompatibility. • The porous gel can be used as novel type of column for water purification.

Anti-collapse performance of concrete-filled steel tubular composite frame with RC shear walls under middle column removal

In this study, the anti-collapse performance of a 1/4 scaled two-story two-bay concrete-filled steel tubular (CFST) composite frame with RC shear walls was experimentally and numerically studied in the scenario of middle column loss through the quasi-static loading method. Test results show that the main failure modes of the specimen were the fracture and local buckling of steel beams, and the concrete crush in the shear walls and the slabs near the failure column. After the steel beam failed, the internal force was transmitted from the steel beams to the CFST columns and shear walls. Based on the refined finite element models, the effects of the column failure positions, limb lengths, reinforcement ratios, and types of shear walls on the collapse resistance of the models were analyzed. Simulation results indicate that the shear wall significantly contributes to resisting vertical load in the initial loading stage. In the large deformation stage, the collapse resistance of the specimen is mainly provided by the sub-framed structure. After the limb length of the shear wall exceeds 2/3 span, the increase in the bearing capacity is not obvious, while the failure displacement is significantly decreased. The reasonable reinforcement ratio of the RC shear wall in the structure should be designed in the range of 0.2%–5%. The local reinforcement methods for the collapse resistance of CFST composite frame with RC shear walls were proposed. In addition, the simplified dynamic analysis and dynamic increase factor (DIF) for the CFST composite frame with RC shear walls were analytically studied by energy balanced method.

In-Tube Solid-Phase Microextraction Directly Coupled to Mass Spectrometric Systems: A Review

Since it was introduced in 1997, in-tube solid-phase microextraction (in-tube SPME), which uses a capillary column as extraction device, has been continuously developed as online microextraction coupled to LC systems (in-tube SPME-LC). In the last decade, new couplings have been evaluated on the basis of state-of-the-art LC instruments, including direct coupling of in-tube SPME to MS/MS systems, without chromatographic separation, for high-throughput analysis. In-tube SPME coupling to MS/MS has been possible thanks to the selectivity of capillary column coatings and MS/MS systems (SRM mode). Different types of capillary columns (wall-coated open-tubular, porous-layer open-tubular, sorbent-packed, porous monolithic rods, or fiber-packed) with selective stationary phases have been developed to increase the sorption capacity and selectivity of in-tube SPME. This review focuses on the in-tube SPME principle, extraction configurations, current advances in direct coupling to MS/MS systems, experimental parameters, coatings, and applications in different areas (food, biological, clinical, and environmental areas) over the last years.

HILIC-MS for Untargeted Profiling of the Free Glycation Product Diversity.

Glycation products produced by the non-enzymatic reaction between reducing carbohydrates and amino compounds have received increasing attention in both food- and health-related research. Although liquid chromatography mass spectrometry (LC-MS) methods for analyzing glycation products already exist, only a few common advanced glycation end products (AGEs) are usually covered by quantitative methods. Untargeted methods for comprehensively analyzing glycation products are still lacking. The aim of this study was to establish a method for simultaneously characterizing a wide range of free glycation products using the untargeted metabolomics approach. In this study, Maillard model systems consisting of a multitude of heterogeneous free glycation products were chosen for systematic method optimization, rather than using a limited number of standard compounds. Three types of hydrophilic interaction liquid chromatography (HILIC) columns (zwitterionic, bare silica, and amide) were tested due to their good retention for polar compounds. The zwitterionic columns showed better performance than the other two types of columns in terms of the detected feature numbers and detected free glycation products. Two zwitterionic columns were selected for further mobile phase optimization. For both columns, the neutral mobile phase provided better peak separation, whereas the acidic condition provided a higher quality of chromatographic peak shapes. The ZIC-cHILIC column operating under acidic conditions offered the best potential to discover glycation products in terms of providing good peak shapes and maintaining comparable compound coverage. Finally, the optimized HILIC-MS method can detect 70% of free glycation product features despite interference from the complex endogenous metabolites from biological matrices, which showed great application potential for glycation research and can help discover new biologically important glycation products.

Axial compression behaviour of rectangular recycled aggregate concrete-filled steel tubular stub columns

Recycled aggregate concrete-filled steel tubular (RACFST) column is a type of composite column that combines the mechanical efficiencies of concrete-filled steel tubular (CFST) columns and the economic and environmental advantages of recycled aggregate concrete (RAC). Till now, experimental and numerical investigations on the axial compressive behaviour of rectangular RACFST columns are not sufficient and design methods for axial compressive stiffness, peak strain and steel tube local stability are still lacking. This study presents experiments on 16 rectangular RACFST stub columns subject to axial compression, investigating the effects of replacement ratio of recycled coarse aggregate (RCA), aspect ratio and depth to thickness ratio of steel tube. The full-range axial load vs. deformation behaviour, working mechanism and failure mode of rectangular RACFST columns are found to be similar to those of natural CFST counterparts, while the occurrence of the first local buckling of steel tube is advanced due to the incorporation of RCA. The increase in replacement ratio negatively affects the axial stiffness of rectangular RACFST columns more than the load-bearing capacity. Nonlinear finite element analysis is subsequentially conducted, and the influences of replacement ratio and aspect ratio on the axial compressive performance and confinement effect of rectangular RACFST columns are numerically studied. On the basis of extensive test data and parametric studies, practical recommendations are finally given for designing the ultimate capacity, axial compressive stiffness, peak strain and tube local buckling of rectangular RACFST stub columns.

Design of concrete-filled steel tubular columns using data-driven methods

By leveraging the merits of structural steel and concrete materials, concrete-filled steel tubular (CFST) structures have been increasingly used in the composite construction of bridges and high-rise buildings. However, their design equations are more complicated than those of steel and reinforced concrete (RC) structures, especially for circular columns under eccentric loading. Therefore, the use of emerging data-driven approaches will help structural engineers ease the design process. This paper explores the use of data-driven design methods as alternatives to conventional mechanics-based design models. Five boosting algorithms, including adaptive boosting (AdaBoost), gradient boosting machine (GBR), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), and categorical gradient boosting (CatBoost), are employed to develop predictive models for four different types of CFST columns (i.e., circular columns, rectangular columns, circular beam–columns, and rectangular beam–columns). These predictive models are trained using the most up-to-date and comprehensive database collected from over 3,200 test specimens. Reliability analysis is conducted to calibrate the resistance reduction factors for three different design frameworks (i.e., the US, Eurocode, and Australian frameworks) to ensure that the newly developed predictive models meet the target reliability indices required by different design frameworks. A web-based design tool is also developed to promote the practical use of data-driven methods for the design of CFST columns.

Clinical case of rhino-orbital mucormycosis in a convalescent COVID-19 patient: diagnostic and treatment tactics

According to current data, SARS-CoV-2 virus has the ability to cause multi-organ pathology, leading to acute damage of various organs and systems and long-term consequences characterized by polymorphic symptoms. Recently, a high incidence of invasive mycoses, particularly mucormycosis COVID-M, has been noted among the COVID-19 complications. The predisposing factor for the development of this pathology is diabetes mellitus, immunodeficiency states, and prolonged use of high doses of glucocorticosteroids. Mucormycosis is characterized by severe clinical manifestations and high lethality, and timely diagnostics of this pathology often represents a difficult problem. The aim of this study was to analyze a clinical case of rhino-orbital mucormycosis in convalescent COVID-19 patient. In the study, there was used mucopurulent nasal discharge from the patient previously hospitalized with a severe novel coronavirus infection. Here, we describe the methodology allowing to isolate and identify a pure mold fungus culture from the biomaterial using methods of routine bacteriology and MALDI-ToF mass spectrometry. Direct microscopy examination of nasal cavity discharge revealed branched non-septic hyphae with a characteristic branching angle, allowing to preliminarily diagnose invasive mucormycosis. Growth of mycelial fungus colony was observed by using Sabourauds medium with potassium tellurite. Microscopy of the pure culture revealed branching mycelium without septa, broad, with irregular thickness, unsegregated hyphae, and sporangia with a typical column specific to mucormycetes. Analysis of the obtained mass spectra allowed to establish the microbial species identity as Lichtheimia corymbifera. The latter along with other members of the order Mucorales, are known to cause mucormycosis. As a result of antifungal treatment (Amphotericin B) and timely surgical intervention, the patient was discharged from the hospital with prominent clinical improvement and no complaints during further outpatient follow-up period. The analysis of this clinical case showed the lack of alertness in some clinical diagnostic laboratories to detect pathogens of invasive mycoses. To avoid errors, while making a diagnosis, attention should be paid not only to detection of fungal spores in clinical material, but also take into account the structure of mycelium underlying major difference between yeast-like fungi, higher and lower molds. The isolation and identification of a pure pathogen culture allows to confidently verify the diagnosis, timely correct the treatment tactics and monitor circulation of mycotic agents to prevent occurrence of mycoses in most vulnerable patients cohorts.

Seismic performance of GFRP tube concrete-encased steel composite columns under axial compression

A glass fiber-reinforced polymer (GFRP) tube concrete-encased steel (GTCES) composite column is a novel column type comprising an outer GFRP tube containing a concrete core and an encased steel section. Although previous studies have examined the static performance of GTCES columns, their seismic performance has not yet been investigated. Therefore, in this study, six GTCES columns with different steel ratios, GFRP tube thicknesses, and axial compression load ratios were tested under combined reversed cyclic lateral loading and static axial compression conditions. The results were used to investigate the influences of these parameters on the failure mode, hysteretic behavior, skeleton curve, ductility coefficient, stiffness, energy dissipation, and strength degradation of GTCES columns. They were found to exhibit favorable seismic performance with excellent ductility and energy dissipation. The steel ratio had a considerable influence on the energy dissipation and carrying ability of the column, and the axial compression load ratio increased its lateral load capacity. Finally, a simplified hysteretic restoring force model for the load-displacement relationship of GTCES columns was established and verified.