Kinds Of Columns Research Articles

Analysis of Big Data Obtained from Continuous Measurement of 22 Malodor-producing Substances in Korean Cattle Farms

Objectives : This research collected continuous (20-minute interval) measurement data of 22 compounds from cattle farms during a year in order to understand malodor emission characteristics and trends and also big data analysis was performed to analyze the relationships between malodor concentration and environmental factors such as wind direction and speed, temperature, and humidity.Methods : The measured substances were 22 compounds defined as ‘designated malodor-producing substances’ by Korean Ministry of Environment. Detection and concentration measurement were performed by gas chromatography with two kinds of columns (VB-WAX, and VB-1), and detectors (FID and PID). Sampling was carried out with pumping every 2 or 5 minute and thermal desorption was followed by chromatograph injection. Data obtained from analysis were stored with environmental variables such as temperature, humidity, wind speed, and wind direction from 1 August 2022 to 31 July 2023. Total number of measurement data was 26,280.Results and Discussion : Correlation analysis showed that temperature was correlated with dimethyl disulfide, and iso-valeraldehyde, and humidity was correlated with toluene, iso-butylalcohol, and trimethylamine. Six principal components explained 60.7% of total variance and two principal components, PC 1 and PC 2, were selected and analyzed. PC 1 was strongly related with volatile organic compounds and PC 2 was related with acid compounds. Together with bipolar plot results, PC 1 was defined as volatile properties and PC 2 as acidic characteristics, respectively. Multiple regression with principal components as dependent variables and environmental variables as independent showed relatively small value of adjusted R2 except PC 1 of 0.539.Conclusion : Malodorous compounds tended to diffuse and move together with similar molecular characteristics which made the detected concentration similar in patterns. Though PC 1 had correlation with environmental variables through multiple regression analysis, it can be explained as chemical compound’s characteristics depends on temperature, humidity, and wind.

Novel prefabricated FRP bar reinforced UHPC shells for column strengthening: Development and axial compression tests

Reinforced concrete (RC) columns are vital components in the construction of large-scale coastal structures, including bridges and piers. Over time, exposure to marine and nearshore environments can lead to a significant deterioration of RC columns. This study introduces an innovative method for strengthening circular concrete columns using two semi-circular shells made from fiber-reinforced polymer (FRP) bar reinforced ultra-high-performance concrete (UHPC), referred to as FRU shells. These semi-circular FRU shells can be easily assembled on-site by connecting them with grouting sleeves, forming a circular tubular jacket that encloses the existing concrete columns. In this study, compression tests were conducted to assess the effectiveness of the proposed strengthening technique. The influence of external FRU jackets with different FRP spacing and various jacket heights was discussed. The results demonstrate that this strengthening approach significantly improves the initial stiffness, ultimate load-bearing capacity, and ductility of the existing circular concrete columns. A theoretical model for predicting the compressive strength of the strengthened columns is proposed and verified against the test results. The proposed prefabricated strengthening system has the potential to be implemented in an underwater environment and to streamline in-situ construction processes for strengthening of various kinds of columns.

Hydrodynamic Performance Study of a Reciprocating Plate Column Dirven by Electro-permanent Magnet Technology

The reciprocating plate column is a kind of column with the plates driven by a geared motor, and it has advantages in regard to efficiency compared to traditional columns in the extraction process, however, it comes with an increase in energy consumption. A new type of reciprocating plate column driven by electro-permanent magnet technology (EPM) is proposed in this paper to obtain a better performance with lower energy consumption. The feasibility and performance of the proposed column is studied by numerical simulation and experiments with a kerosene–water system. The electro-permanent magnet chuck could provide a maximum amplitude of 12 mm in this study. Kerosene was used as the dispersed phase, and deionized water was used as the continuous phase, in a laboratory-scale 35 mm diameter reciprocating plate column driven by EPM. Hydrodynamic performance experiments were carried out with different flowrates of both phases and reciprocating frequencies. The experimental results show that the electro-permanent magnet chuck, which serves as the driving device of the reciprocating plate column, plays the role of adding energy and increasing the droplet breakage. In addition, the energy consumption of the reciprocating plate column with traditional geared motor and electro-permanent magnet chuck is calculated respectively. Compared with the traditional geared motor, the energy saving of the electro-permanent magnet chuck is as high as 98.55%.

Seismic performance of ternary composite geopolymer recycled concrete columns: Experimental study and modeling

In order to achieve seismic-resistant structures cast from green building materials, a new kind of column, ternary composite geopolymer concrete with recycled aggregates containing recycled fireclay brick aggregates (GRA-RFBAC) column, was proposed in this paper. The ternary binder material in GRA-RFBAC was produced by the combination of industrial by-products (ground granulated blast furnace slag (GGBS), recycled fireclay brick powder (RFBP), and fly ash (FA)) and alkali-activated solution. Cyclic loading tests of five reinforced GRA-RFBAC columns, each with a shear-to-span ratio of 3.07, were conducted to investigate the seismic performance. The influence of the recycled aggregate containing recycled fireclay brick aggregate (RA-RFBA) replacement ratio, stirrup spacing, and axial compression ratio on the seismic performance of GRA-RFBAC columns was discussed. The results indicated that all specimens showed similar flexural failure modes under cyclic loading. The first cracking of concrete occurred within the drift ratio range of 0.18%–0.41%, the failure drift ratio varied from 3.27% to 4.11%, and the peak load of the specimens ranged from 237.50 kN to 288.87 kN. Although increasing the RA-RFBA replacement ratio led to a decrease in both the bearing capacity and lateral stiffness of the columns, the GRA-RFBAC columns showed comparable or even better seismic performance than Portland cement concrete columns. Moreover, a prediction model for the skeleton curve of GRA-RFBAC columns was proposed and verified by comparing the prediction results with the test results.

High-Performance Liquid Chromatography (HPLC): Primary Mechanism and Popular Applications

The concept chromatography can be used to refer to a huge variety of distinct analytical procedures. Each of these procedures utilizes a mobile phase and an immobile phase as a basic component, yet they all belong under the chromatography umbrella concept. The subsequent component separation that is carried out is based on the disparity in concentration ratio that can be detected between the two phases. This disparity acts as the basis for the subsequent component separation that is carried out. Due to the limits of current technology, there is presently no detector that is universally applicable to high-performance liquid chromatography (HPLC), it is required to choose a detector in accordance with the characteristics of the chemicals that are to be examined. The measurements of absorbance in ultraviolet and visible spectrum, known as UV-Vis, or disclosing fluorescence are the foundations of the most common types of fluorescence detectors. In HPLC the components of the apparatus consist of a carrier phase, which is typically a solvent with a buffer solution; a pump; an injector; a column; a detector; and an integrator. The column is the most important part of the system where the various components are separated from one another. Based on that, there are many various kinds of columns through which the behavior of the components to be separated by these columns is understood. Due to the fact that chromatography is such a widely used technology.

A data-driven model of drop size prediction based on artificial neural networks using small-scale data sets

An artificial neural network (ANN) method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets. After training, the deviation between calculate and experimental results are 3.8% and 9.3%, respectively. Through ANN model, the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed. Droplet size gradually increases with the increase of interfacial tension, and decreases with the increase of pulse intensity. It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range. For two kinds of columns, the drop size prediction deviations of ANN model are 9.6% and 18.5% and the deviations in correlations are 11% and 15%.

Effects of stacking sequences on the axial compressive buckling behavior and failure characteristics of channel-section CFRP/Al laminate columns

Open-section composite profiles are often used as columns in civil engineering structures. Their thin-walled nature makes these sections prone to buckling phenomena when loaded in compression. This paper presents a study on the axial compressive performances and failure behavior of channel-section CFRP/Al laminate columns with two different stacking sequences. Typical mechanical responses and failure characteristics were first explored through experiments. Then the damage propagation mechanisms of the two kinds of columns were further compared based on a three-dimensional progressive damage model. The results indicated that column with CFRP layers stacked on the exterior surfaces exhibited smaller delaminated areas compared with the ones with aluminum alloy layers stacked exteriorly, thus resulting in the higher load-bearing capacities. Finally, a concise theoretical calculation equation for buckling load was derived, based on which further structural parametric analysis were performed.

Structural behavior of tree-like steel columns subjected to combined axial and lateral loads

Abstract Few studies have been conducted on the structural behavior of steel columns with branches that are called tree-like columns. These kinds of columns have been used in many structures around the world. The purpose of this study is to investigate the failure load, vertical and lateral displacement, and failure mode of tree-like columns subjected to a combination of axial and lateral loading. The ratio of lateral load to axial load has been selected as the design variable. A finite element model with one branching level and two branches within the level was first developed using ABAQUS/CAE 2017 software. The model was verified with experimental results. The axial failure load and axial and lateral displacement were determined and compared for different loading ratios. The failure mode was also studied for different loading conditions. The results showed that the axial failure load decreased significantly by 54, 42, and 28% when lateral/axial loading ratio increased by 20, 40, and 60%, respectively. There was no significant decrease when lateral/axial loading ratio was more than 60%, while axial and lateral displacements increased significantly by 24% for each 20% increase in the loading ratio. Local buckling was observed as a failure mode when only gravity load is applied, while combined load resulted in lateral buckling.

Preparation of Monolithic Silica and Polymer Capillary Columns with Ultrahigh Column Efficiencies and Comparisons between van Deemter Plots of Alkylbenzenes on These Two Kinds of Columns.

Monolithic silica and polymer capillary columns with ultrahigh column efficiencies were prepared. Permeability and electrochromatography performances of these two kinds of columns were compared. Monolithic silica columns bear higher permeability than polymer counterparts by two orders of magnitude. Furthermore, the van Deemter plots of alkylbenzenes on these two kinds of columns demonstrate that monolithic silica columns produce much lower plate heights of alkylbenzes than polymer columns do. Within the range of electroosmotic flow (EOF) velocity investigated, no uptrend of plate height with the increase of EOF was observed suggesting the great capacity of fast separation and high efficiency. The plate height of thiourea on monolithic silica columns is as low as 2.67μm, representing its corresponding column efficiency is over 430,000plates/m. As far as we know, it is the highest ever column efficiency reported in the literature. Moreover, the separation of butylbenzene isomers was obtained on the monolithic silica column.

Experimental study on cold-formed lipped channel stub columns reinforced by steel bars or steel strips

In this paper, the axial compressive properties of cold-formed steel lipped channel stub columns strengthened by rebars or steel strips are experimentally studied. The experiment included two sections. A kind of columns with local buckling is reinforced longitudinally by steel strips at the web. The other is the columns with distorted buckling, which is reinforced longitudinally by steel bars at the curling edge. The failure mode, deformation characteristics, ultimate bearing capacity and load displacement curve of the specimen are obtained through the experiment. On the basis of the experiment, the calculation results of theoretical axial bearing capacity of cold-formed steel lipped channel stub columns in Chinese, North American and Australian code are compared and analyzed. Research indicates: First, the cold-formed steel lipped channel stub columns strengthened by steel bars or steel strips can effectively improve the compressive bearing capacity of the specimen. Secondly, when the initial stress ratio of specimen is less than 0.3, the reinforcement effect is ideal. Thirdly, the three standards don't stipulate the calculation of theoretical bearing capacity of the specimen strengthened after loading, so there is a large deviation between the theoretical calculation value and the test value.

Review: Architecture, Liberty and Civic Order: Architectural Theories from Vitruvius to Jefferson and Beyond, by Carroll William Westfall

Review: <i>Architecture, Liberty and Civic Order: Architectural Theories from Vitruvius to Jefferson and Beyond</i>, by Carroll William Westfall

Experimental study on the seismic damage behavior of aeolian sand concrete columns

ABSTRACTIn order to promote the application of aeolian sand in concrete frame structures, it is necessary to study the seismic damage performance of aeolian sand concrete columns. In this paper, 4 concrete column specimens with different replacement percentages of aeolian sand were tested under lateral cyclic loading. The 4 replacement percentages of aeolian sand were 0%, 10%, 20%, and 30%. The seismic damage process of the specimens was studied by comparing the seismic indexes exhibited in the test. Then, the damage model of the specimens was studied. The results showed that the specimen whose replacement percentage of aeolian sand reached 30% had superior seismic damage performance. Its degree of damage was smaller than that of the other specimens under the same conditions. Its seismic indexes, including the bearing capacity, ductility, stiffness degradation, and energy dissipation capacity, performed much better than those of the other specimens. Besides, this paper proposes a damage model of an aeolian sand concrete column based on current results. This model can be used to evaluate the damage degree of this kind of column.

Hysteretic behavior of multi-cell L-shaped concrete-filled steel tubular columns at different loading angles

Multi-cell L-shaped concrete-filled steel tubular (CFST) columns have the advantages of avoiding column protrusion, saving room space and good mechanical behavior. They can be used as the corner columns in building structures. In practical engineering, the columns may be subjected to earthquake action from different directions. However, there are few experimental and numerical studies on this kind of columns at different loading angles. This paper presents four tests carried out on multi-cell L-shaped CFST columns subjected to combined constant compression and lateral cyclic loads. The main variables were loading angles (0°, 45° and 135°) and axial load levels (0.25 and 0.5). The failure modes, lateral load – displacement hysteretic curves, envelope curves, stiffness degradation, ductility, energy dissipation, deformation and moment – curvature curves were obtained. A finite element model was developed to simulate the multi-cell L-shaped CFST columns at different loading angles, and the predicted results agreed well with the test results. Moreover, the parametric analysis was conducted to investigate the effects of various parameters on lateral load – displacement curves of the columns under diagonal loading.

Finite element analysis and axial bearing capacity of steel reinforced recycled concrete filled square steel tube columns

This paper presents a finite element model which can simulate the axial compression behavior of steel reinforced recycled concrete (SRRC) filled square steel tube columns using the ABAQUS software. The analytical model was established by selecting the reasonable nonlinear analysis theory and the constitutive relationship of material in the columns. The nonlinear analysis of failure modes, deformation characteristics, stress nephogram, and load-strain curves of columns under axial loads was performed in detail. Meanwhile, the influences of recycled coarse aggregate (RCA) replacement percentage, profile steel ratio, width thickness ratio of square steel tube, RAC strength and slenderness ratio on the axial compression behavior of columns were also analyzed carefully. It shows that the results of finite element analysis are in good agreement with the experimental results, which verifies the validity of the analytical model. The axial bearing capacity of columns decreased with the increase of RCA replacement percentage. While the increase of wall thickness of square steel tube, profile steel ratio and RAC strength were all beneficial to improve the bearing capacity of columns. Additionally, the parameter analysis of finite element analysis on the columns was also carried out by using the above numerical model. In general, the SRRC filled square steel tube columns have high bearing capacity and good deformation ability. On the basis of the above analysis, a modified formula based on the American ANSI/AISC 360-10 was proposed to calculate the nominal axial bearing capacity of the columns under axial loads. The research conclusions can provide some references for the engineering application of this kind of columns.

Seismic Damage Behavior of Aeolian Sand Concrete Columns with an Inner Square Steel Tube

In order to promote the application of aeolian sand in steel‐concrete composite structures, the aeolian sand concrete columns with an inner square steel tube is proposed in this paper. This kind of column is composed of aeolian sand concrete, reinforcing steel, and an inner square steel tube. The seismic damage behavior of the column was studied through cyclic loading test and damage analysis on seven specimens with different structural forms. The seismic damage indices of the specimens in this study include the failure mode, bearing capacity, ductility, stiffness, hysteresis behavior, and energy dissipation. Then, a damage model of this kind of column is proposed. The study results show that installing an inner square steel tube can significantly improve the seismic damage behavior of aeolian sand concrete columns. This mode of construction can be used to enhance the replacement percentage of aeolian sand. In addition, the damage model proposed in this paper agrees well with the experimental results and can be used to evaluate the damage degree of the aeolian sand concrete columns with an inner square steel tube.

Behavior of Concrete‐Filled Steel Tube Columns Subjected to Axial Compression

The behavior of concrete‐filled steel tube (CFST) columns subjected to axial compression was experimentally investigated in this paper. Two kinds of columns, including CFST columns with foundation and columns without foundation, were tested. Columns of pure concrete and concrete with reinforcing bars as well as two steel tube thicknesses were considered. The experimental results showed that the CFST column with reinforcing bars has a higher bearing capacity, more effective plastic behavior, and greater toughness, and the elastoplastic boundary point occurs when the load is approximately 0.4–0.5 times of the ultimate bearing capacity. The change of rock‐socketed depth and the presence of steel tube will affect the ultimate bearing capacity of rock‐socketed pile. The bearing capacities of the rock‐socketed CFST columns are lower than those of rock‐socketed columns without a steel tube under a vertical load; besides, the greater the rock‐socketed depth, the greater the bearing capacity of the rock‐socketed piles. In addition, a numerical comparison between the ultimate load and the theoretical value calculated from the relevant specifications shows that the ultimate load is generally considerably greater than the theoretical calculation results.

DEVELOPMENT OF RECOMBINANT PEPTIDE TECHNOLOGY WITH ANTIMICROBIAL PROPERTIES OF A BROAD ACTION SPECTRUM

Bacteriocins are antibacterial, mainly complex, substances of protein nature. The promising strains producing bacteriocins used in the food industry are lactic acid microorganisms. This study examines the development of a technology for the production of a recombinant peptide with broad-spectrum antimicrobial properties. An important step is the isolation and purification of the recombinant peptide. It has been proved that the highest antimicrobial activity is manifested by a recombinant peptide isolated by a method based on salting out with ammonium sulfate. During the purification of the recombinant bacteriocin preparation, three kinds of columns were used. In the purification process, the volume of bacteriocin produced decreases 3-fold, while the RU/mL increases 3-fold, and RU/mg increases 6-fold. Purification allows the use of a smaller amount of recombinant bacteriocin in technologies with greater efficacy. Based on the results of determining the molecular weight and purity of the recombinant bacteriocin, it was found that the molecular weight of the recombinant bacteriocin having the amino acid sequence: KYYGNGVTCCKHSCSVDXGKASSCIINNGAMAXATGGH GGNHCCGMSRYIQGIPDFLRGYLHGISSANKHKKGRL, is 13 kDa. A technology for the preparation of a broad-action antimicrobial spectrum peptide has been developed. The process of production of antimicrobial peptide includes such stages as: cultivation of the recombinant strain of Escherichia coli BL21DE3; separation of biomass from the nutrient medium; precipitation of bacteriocins by ammonium sulfate; centrifugation; washing the precipitate; centrifugation at 4200 rpm and separation of the preparation; purification of bacteriocins by HPLC method; packing in bags of polymeric and combined materials; storage at a temperature of 18±2°C for 12 months.

Buckling of Standing Tapered Timoshenko Columns with Varying Flexural Rigidity Under Combined Loadings

The stability of a nonuniform column subjected to a tip force and axially distributed loading is investigated based on the Timoshenko beam theory. An emphasis is placed on buckling of a standing column with varying cross-section and variable material properties under self-weight and tip force. Four kinds of columns with different taper ratios are analyzed. A new initial value method is suggested to determine critical tip force and axial loading at buckling. The effectiveness of the method is confirmed by comparing our results with those for Euler–Bernoulli columns for the case of sufficiently large shear rigidity. The effects of shear rigidity, taper ratio, and gravity loading on the buckling loads of a heavy standing or hanging column are examined.

Detection sensitivity of red cell alloantibodies using microtube column agglutination systems

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Experimental study and parameter analysis of L-shaped composite column under axial loading

A special-shaped column composed of concrete-filled steel tubes (SCFST column) is experimentally investigated in this paper. The SCFST column is composed of several small-sized concrete-filled square tubular columns (mono-columns) connected by connection plates. This kind of column is proposed because it can increase the usable space in residential buildings. The axial loading behavior of L-shaped SCFST columns is experimentally investigated. The failure mode, strain distribution, cooperation of mono-columns, bearing capacity, and the effect of a concrete core on column behavior were tested. As concluded, the SCFST column can be regarded as a useful kind of column. A finite element analysis model was proposed according to the experimental results, and the influence of connection plate size on bearing capacity was studied using the finite element model. Finally, proposed were the optimal width and thickness of connection plates for improving the design of the SCFST column.