Plastic Columns Research Articles

Adsorption and Leaching of Deltamethrin Pesticide in Alluvial Soil Under Laboratory and Field Conditions

This study was carried out to assess the adsorption and leaching activities of deltamethrin pesticide in soil and water. Experiments in the lab and in the field were used to better understand these processes and the factors that influence them. Sections of the adsorption experiment were separated into kinetic and steady-state. Pseudo-first and second-order models were used to evaluate the kinetic data. Deltamethrin kinetic adsorption on soil was shown to be pseudo second order, with a rate constant of 4.625 mg/g/h. Using the Langmuir and Freundlich isotherms, it was determined that Freundlich's isotherm was well-observed, with adsorption capacities of 0.164-0.861 mole per gramme, based on the equilibrium data. In the lab, leaching experiments were carried out in 30-cm-long plastic columns. After adsorption, 500 ml of water was used to elute a known amount of deltamethrin insecticide from the column. It was discovered that the deltamethrin concentration fell from 0.405 ng/l in the first portion of the water to 0.0601 ng/l in the last portion of the water and 2.584 ng/l in the first section of column soil to 0.278 ng/l in the third section of column soil. Deltamethrin's leaching capability was tested in the field to a depth of 30 cm, and its concentration declined as soil depth increased. In the first piece of soil, it was 10.518 ng/l, and in the third, it was 0.354 ng/l. It was discovered in this investigation that deltamethrin insecticide leached to 30 cm depth because to minimal organic matter, sandy texture and basic pH. Keywords: Adsorption; Deltamethrin; Leaching; Soil; Water

Septage effluent treatment using floating constructed wetland with Spirodela polyrhiza: Response of biochar addition in the support matrix

Amendments and modifications in conventional methods are continuously required to make wastewater treatment cost-effective, easy to handle, and eco-friendly. Given that, the present study aimed to investigate the efficacy of duckweed (Spirodela polyrhiza)-based multilayer floating constructed wetland (CW) with wood biochar (BC), as carbon stock in the support matrix for treatment of septage effluent. For that four different setups: S+BC+DW (sand + BC + duckweed), S+BC (sand + BC); S (sand); DW (duckweed) were prepared using PVC plastic columns (30 cm length × 11 cm Ø) filled with support matrix and changes in effluent parameters i.e., biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN), ammonium N (NH4+-N), nitrate (NO3-N), phosphate (PO4−3), and sulphate (SO4−2) were monitored after each 24 h interval for 168 hr HRT. The maximum reduction in PO4−3, TN, NH4+-N, BOD, COD, SO4−2 and NO3-N load was found to be 68.43 %, 64.29 %; 66.41 %, 81.87 %, 58.02 %, 60.48 %, and 64.45%, respectively in S+BC+DW setup. The performance of the studied CW setups was in the order: S+BC+DW> S+BC > S > DW. Phytoremediation assisted by BC-meditated adsorption and chemical oxidation could be the major mechanisms for septage effluent treatment in different CW setups. The results of the study could be beneficial for developing nature-based-low-cost septage treatment setups for rural areas under the decentralized wastewater treatment tools.

Using 3D printed formworks for the creation of steel fibre reinforced concrete-plastic columns

A concept of steel fibre reinforced concrete–plastic columns was proved and discussed in the paper. Plastic was playing the role of stay-in-place 3D printed formwork. Seven cross-sections representing different types of shapes of columns (from circular to fractal-based) were created. 3D printed plastic stay-in-place formworks were filled with steel fibre reinforced concrete. After ordinary curing, the specimens were loaded. During the tests load–strain characteristics were recorded. Both the destruction characteristics and the energy dissipated during the loading up to 3.5% strain were of special interest. The achieved results were analysed and discussed. Columns with traditional circular and square cross-section were characterized by sudden destruction of the formworks. Specimens with fractal-based cross-sections were characterized by a very smooth destruction process associated with significant deformations of formworks. All steel fibre reinforced concrete–plastic columns in question were characterized by highly quasi-plastic behaviour. The achieved results proved that it is feasible to replace traditional formwork and ordinary concrete (reinforced by steel bars and stirrups) by much more automatized 3D printing of plastic and steel fibre reinforced concrete based solution. The future aims of the much needed research should cover both large scale column specimens and other structural elements.

Concrete Filled Plastic Stub Columns Strength under Axial Compression

The development of Concrete Filled Plastic Tube (CFPT) Stub Columns, is commonly used in the areas where the concrete structures interact with marine and saline environments, compared to regular concrete columns. Several CFPT stub column samples were prepared to investigate their behaviour under certain loading conditions. The main objective of this study was to conduct an experimental investigation to observe the effect of using CFPT with different diameters on the final strength of the concrete columns. In order to achieve this target, two types of loading conditions were applied, including separate load on the concrete and combined load on the concrete and the plastic tube simultaneously. The study revealed a significant improvement in the compressive strength of CFPT columns with different diameters (70 - 100 - 150 mm). Overall results show that the use of CFPT columns provides better mechanical performance compared to ordinary concrete columns. An evaluation of using the available calculation methods to predict the load-carrying capacities of CFPT. The study suggested the use of CFPT columns in situations where common concrete may cause significant issues related to its deterioration and disintegration in response to severe weather conditions.

Hysteretic behavior of circular tubed reinforced concrete column to steel beam frames

Tubed reinforced concrete (TRC) columns have good deformability and energy dissipation capacity under horizontal cyclic loads; and even with plastic hinges formed at the column ends, the corresponding frame structure may still have sufficient inter-story deformation capacity. Extensive research has been conducted on the static and seismic performances of TRC columns. However, little attention has been paid to the structural system containing TRC columns. To overcome this shortcoming, an experimental study on the seismic behavior of circular tubed reinforced concrete (CTRC) column to steel beam frames (referred as “CTRC frames”) is described first in this study. Based on the previous studies on CTRC columns and joints, two double-bay two-story CTRC frames of 1/2 scale were designed and tested under quasi-static loading: one frame with stronger flexural strength in columns than the beams and the other frame is the opposite. The test results indicated that although the frame failed in column plastic hinge mode had the ductility coefficient of 3.56, a weak story with the maximum story drift ratio of 1/18 formed in this frame, which increased the collapse risk of the overall structure. Therefore, considering the unfavorable deformation mode, the column plastic hinge mode should be avoided in practical designs; and the control of frame deformation modes should be considered when proposing a suitable column-beam strength ratio for CTRC frames. A fiber-based element model using OpenSees software was developed, which showed a good agreement with the test results. Utilizing the numerical model, the affecting parameters to the hysteretic behavior of CTRC frames, such as the axial load ratio, concrete compressive strength, and column-beam strength ratio, were further investigated.

A Sustainable and Low-Cost Soil Filter Column for Removing Pathogens from Swine Wastewater: The Role of Endogenous Soil Protozoa

The increase of swine production in the Pacific Islands has inevitably led to environmental pollution concerns from discharged wastewater derived from both washing and manure. The slurry accumulates in lagoons, where supernatant wastewater containing high levels of pathogens and nutrients becomes nonpoint source water pollution that deteriorates the quality of receiving water bodies. Soil filtration is a promising cost-effective technology for removing pollutants from swine wastewater; however, the excessive growth of bacteria in soil media often accompanies the filtration process. This study investigates soil filtration mediated by protozoa activities to remove Escherichia coli (E. coli) in synthetic swine wastewater. The experiment used plastic columns packed with Leilehua soil from Oahu Island, Hawaii. The soil physicochemical adsorption was seen to reduce 95.52–96.47% of E. coli. However, the average removal efficiencies were increased to 98.17% in a single stage, and 99.99% in two sequential columns, under predation conditions. The filtration media containing naturally established bacterivores with the prey, provided a bioactive means to remove E. coli from the influent. The proper design of Leilehua soil filters potentially removes E. coli from the influent to meet the standard level of recycled water.

Evaluation of Using Magnetized Water in Leaching Salts in Sandy Loam Soil

Many studies and researchers have reported significant evidence that some physical properties of water can be changed as it passes through a magnetic field that can improve water use. This can have a promising potential for applications, especially in the fields of irrigation and drainage. In this research, magnetized water was used to leach salt-affected sandy loam soil. A test rig was designed and constructed to investigate the effects of magnetized water on leaching soil. The rig consists of a magnetization device that can provide variable intensity. Water was supplied from a constant head reservoir to the magnetization device then to the soils that were placed in plastic columns. Five different magnetic intensities and five different times of exposing the flow of water to the magnetic field were applied. The time of exposure to the magnetic field was represented by the flow velocity of the flow passing through the magnetic field. The treated water is applied to leach each soil column in three consecutive leaching processes. Leaching water drained from the soil samples were tested for EC and pH, K+, Na+, Mg+2, Ca+2, Cl-, HCO-3, and SO4-2. The results showed that the efficiency of magnetized water in removing salts from the soil is more than the untreated water. As the magnetic intensity and exposure time are increased, more salts were leached out of the soil. When comparing the experiments conducted with magnetized water with that untreated water, the maximum increase in the EC value was 58.6%, and in the pH values was of 2.4%.

Strength of Concrete-Filled Plastic Tube Stub Columns Using a Normalized Stiffness Approach

The polymeric plastic tube can encase concrete and provide an external shell for confining and insulating concrete core from the impact of the surrounding environment. The effect of the tube and concrete strength on the concrete-filled plastic tubes (CFPT) stub columns specimens was investigated. Test results show that the tube provides passive confinement to the concrete core, which increases both the maximum peak load and the ultimate strain capacities. However, the tube has low stiffness, which affects its confinement capacity and hindrance its applications for structural use. To examine the role of tube stiffness and express the strength of a concrete-filled plastic tube, a previously proposed normalized stiffness approach for both active and passive confinement of FRP-confined concrete was adopted for the present study. From the perspective of stiffness and to better understand the behavior of CFPT specimens under uniaxial compression loads, a database of recent studies were assembled combined with the results of the present study. Several existing strength models for FRP-confined concrete were also used to predict the mechanical strength of CFPT. Two models were proposed with good predictions of the experimental results of the database.

Inelastic Responses and Finite Element Predictions of Fiber Cementitious Composite and Concrete Columns.

In this research, reinforced concrete (RC) and strain-hardening cementitious composite (SHCC) columns subjected to lateral loads combined with a constant load were investigated, both by experiments and predictions, with two distributed inelastic finite element models established by the stiffness and flexibility formulations. SHCC applied in the column plastic hinge region could not only enhance the lateral load and displacement capacities of columns but also offer effective advantages in the control of bending and shear cracks induced by multiple microcracks, the prevention of the spalling of cover concrete, and the resistance to buckling of steel bars. With the layered cross-sectional approach using constitutive laws of SHCC considering a proposed model of the post-cracked high-ductile tensile characteristics, as well as concrete and reinforcing steel bars, an inelastic beam-column finite element model was presented with a distributed flexibility formulation. In comparison with experiments concerning the RC and reinforced strain-hardening cementitious composite (R-SHCC) columns, the current flexibility method showed relatively accurate estimations in the lateral load and displacement responses of column systems as well as in localized nonlinear responses of cross-section as estimated in axial strains of longitudinal reinforcing steel bars. In comparison with the stiffness method, the current flexibility method gave more accurate solutions at both element and structural levels, as manifested in the experiments and analysis solutions.

Concept of Using 3D Printing for Production of Concrete-Plastic Columns with Unconventional Cross-Sections.

A concept of concrete–plastic columns was presented in the paper. As a proof of concept, a research program was conducted. Seven different cross-sections of columns formwork were 3D printed using plastic. The cross-sections represented three types of columns’ shapes: most common, rare, and impossible to be realized using traditional formworks (based on fractals). Prepared plastic formworks were filled with cement mortar playing the role of ordinary concrete. After 28 days of curing, the load–strain characteristics of all the concrete columns were tested. Achieved results were discussed. It was proven that concrete–plastic columns were characterized by quasi-plastic behavior while being ultimately destroyed. Columns with fractal-based cross-sections sustained the largest strains while maintaining a significant part of the maximum load. The achieved results proved that it is possible to completely omit traditional steel rebar-stirrup reinforcement. The future direction of needed research should cover larger columns and other concrete–plastic elements. Using fiber-reinforced concrete for the creation of concrete–plastic elements should be also tested.

Behaviour Factor of Ductile Code-Designed Reinforced Concrete Frames

The current generation of seismic design codes is based on a linear elastic force-based approach that includes the nonlinear response of the structure implicitly through a response modification factor (named reduction factor R in American codes or behaviour factor q in European codes). However, the use of a prescribed behaviour factor that is constant for a given structural system may fail in providing structures with the same risk level. In this paper, the behaviour factor of reinforced concrete frame structures is estimated by means of nonlinear static (pushover) and nonlinear incremental dynamic analyses. For this purpose, regular reinforced concrete frames of three, five, seven, and nine storeys designed for high ductility class according to the European and Italian seismic codes are investigated, and realistic input ground motions are selected based on the design spectra. Verified analysis tools and refined structural models are used for nonlinear analysis. Overstrength, redundancy, and ductility response modification factors are estimated, and the effects of some parameters influencing the behaviour factor, including the number of bays and the number of storeys, are evaluated. The results are finally compared with those obtained from a previous paper for steel moment-resisting frames with the same geometry. According to the analysis results, the behaviour factors in the case of pushover analysis are significantly higher than those obtained in the case of nonlinear response history analysis. Thus, according to the pushover analysis, the behaviour factor provided by European and Italian standards seems highly conservative. On the contrary, the more refined nonlinear dynamic analysis shows that the code-prescribed value may be slightly nonconservative for middle-high-rise frame structures due to unfavourable premature collapse mechanisms based on column plastic hinging at the first storey. Thus, some modifications are desirable in local ductility criteria and/or structural detailing of high ductility columns to implicitly ensure that the recommended value of the behaviour factor is conservative.

Investigation of the seismic performance of braced low-, mid- and high-rise modular steel building prototypes

For buildings with repeatable units, modular construction provides an alternative to traditional on-site construction. Modular steel buildings (MSBs) are composed of prefabricated volumetric modules that are produced in a controlled environment such as a factory to be transported and assembled on-site to form a larger, permanent building. Although the studies on the dynamic behavior of modular buildings are limited to up to 10-story MSBs, the recently completed 32-story MSB in New York showcased the applicability of this type of construction beyond mid-rise structures. Additionally, in the National Building Code of Canada both the ductility modification factor and the overstrength modification factor are determined based on the type of the seismic force resisting system, regardless of the building height. Previous studies indicated that neglecting the correlation between these design factors and the height of the building could lead to inadequate design as the building height increases. The current paper assesses the seismic design factors and the seismic performances of 6-, 12, and 32-story MSBs by means of pushover analyses and bi-directional nonlinear time history analyses. The seismic performance is evaluated in terms of interstory drift, residual drift, and base shear. Pushover curves indicated that both overstrength and ductility factors decrease as the height of the building increases. Data from the time history analysis revealed that high-rise MSBs tend to exceed collapse prevention limit and develop column plastic hinges under severe ground motions. On the other hand, the residual drift ratio was found to be more pronounced in low- to mid-rise MSBs.

Effect of Strong Column Weak Beam Concept on Seismic Capacity of Buildings of Varying Heights: A Review

The strong-column-weak-beam (SCWB) layout philosophy in which plastic deformation is authorized to arise most effective with inside the beams whilst the columns continue to be basically elastic is broadly followed in seismic layout codes for metallic second frames. Under this yield mechanism, the seismic strength is dissipated ordinarily with the aid of using the plastic hinges with inside the beams and on the column bases. The relative plastic flexural capacities of the beams and column bases can drastically have an impact at the response of a SCWB frame. During beyond earthquakes column plastic hinges are extra crucial than beam hinges which offers upward push to worldwide structural harm and excessive existence threatening risk. All the structural components transfers their forces through column and then column shares it with foundation to soil, so u can imagine if column fails whole structure can collapse this is strong beam weak column concept. Keywords: RC frame buildings, Strong-column weak-beam design, Push over analysis.

Damping characteristics of PVA fiber-reinforced cementitious composite containing high-volume fly ash under frequency-temperature coupling effects

The service life of concrete structures is often threatened by unfavorable dynamic loads. Optimizing the material damping can improve the vibration damping of the structure. In this study, a polyvinyl alcohol fiber-reinforced high-volume fly ash (PVA-HVFA) cementitious composite was developed with high damping characteristics and moderate mechanical properties. The coupling effects of frequency and temperature on the damping were further clarified. Experiments combined with MIP and SEM tests were performed to analyze the pore structure distribution, fiber–matrix morphology, and enhanced damping mechanism. The results showed that the large amount of FA adversely affected strengths of the PVA-HVFA but significantly improved the damping and energy dissipation capacity. Meanwhile, the PVA fibers enhanced both strengths and damping characteristics. Vibration damping and energy dissipation were hypothesized to be affected by the matrix, fibers, and fiber–matrix interface. PVA-HVFA is expected to be applicable to beam–column plastic hinges and other vibrational damping fields.

Seismic collapse assessment of new European single-story RC precast buildings with weak connections

Capacity design, according to the modern seismic building codes, requires the application of specific rules and construction details in order to prevent brittle failure modes at material, element and structural level. In particular, with reference to single-story precast reinforced concrete structures with columns joined by pinned beams, the Italian seismic building code, following the Eurocode 8 general principles, requires that beam-to-column connection should be designed in order to avoid the connection failure before the formation of the plastic hinge at the column base. However, no specific details are provided in order to reach such a performance. Recent European earthquakes showed that seismic performance of beam-to-column dowel connections can be very poor. Hence, for European typical dowel beam-to-column connections, this study aims to investigate: (a) possible connection configurations obtained according to seismic design; (b) possible failure modes involving connection elements (steel dowel, transversal steel reinforcement, dowel concrete cover); (c) how available formulations are able to describe such failure modes and the related shear strength; (d) influence of connection failure on the global seismic safety at collapse of new designed single-story RC precast buildings. The reference buildings and beam-to-column connections are designed considering different geometrical layouts of the primary structure and different seismic hazard levels, i.e. four sites and two soil types. Structural capacity is estimated considering global, i.e. related to column plastic hinge degradation measured in terms of top lateral displacements, and local, i.e. related to connection shear strength, failure modes. Nonlinear multi-stripe analyses are performed for the seismic assessment.

Lateral cyclic testing and backbone curve development of high-strength steel built-up box columns under axial compression

The AISC 341 (2016) has a more stringent width-to-thickness (b/t) limit for highly ductile hollow box columns (HBCs) than the AIJ (2010) or Taiwan Code (2010), resulting in significant thickness difference in design. Moreover, the cyclic backbone curves based on ASCE 41 (2013) and NIST (2017) underestimate the post-buckling flexural strength of HBCs, particularly in high axial compression force. This paper presents test results of six full-scale, built-up HBCs using SM 570 M steel with the actual yield strength of 460–530 MPa. The lateral cyclic behavior of built-up columns was studied in terms of different b/t ratios, magnitudes of axial compression forces, and lateral drift histories (i.e., cyclically symmetric versus near-fault displacement histories). The built-up box columns were 290–400 mm wide with b/t ratios from 11 to 21, 4000 mm high, and tested laterally with both ends fixed after under a constant axial compression force, 2591–7935 kN. The HBC specimens which were designed based on the highly ductile member requirement in AISC 341 (2016), even under an axial compression force (=40%Py), performed satisfactorily at 4% drift and experienced flange and web fracture at 5% drift. However, the HBC specimens that satisfied the most compact b/t requirement in AIJ (2010) or Taiwan code (2010) did not perform well at 4% drift, losing the axial capacity after significant column local buckling and shortening. The gathered test data, supported by more test data in this work, were analyzed by a multiple regression method to obtain empirical formulations for predicting the maximum column moment, plastic rotation and post-yield hardening parameters. The proposed formulation reasonably predicts the first-cycle envelope curves of built-up HBCs, improving prediction results based on ASCE 41 (2013) and NIST (2017).

Purification of Polyhistidine-Tagged Proteins by Immobilized Metal Affinity Chromatography.

Immobilized metal affinity chromatography (IMAC) is based on the affinity of polyhistidine tracts for divalent metal cations (usually Ni2+) immobilized as transition metal chelate complexes on a chromatography resin. The main protocol here is optimized for use of Ni2+-NTA resin to purify soluble 6xHis-tagged proteins by a straightforward batch method during the binding step, followed by gravity flow for washes and elution. This protocol does not require any specialized equipment other than a simple glass or plastic column. IMAC resins can be used in multiple formats, including batch, gravity flow, centrifuge columns, and fast performance liquid chromatography (FPLC) systems. FPLC systems are designed specifically for the chromatographic separations of proteins and other biomolecules. These systems typically contain multiple pumps, an in-line UV absorption monitor, conductivity meter, pH meter, fraction collector, and other options that allow for the simultaneous purification, analysis, and fractionation of the sample. When linked with the appropriate instruments, an FPLC can become a high-precision, automated instrument that separates proteins at a high resolution. An alternative protocol is included here that describes 6xHis-tagged protein purification using FPLC. Procedures for the cleaning and regeneration of the IMAC resin for reuse are also described, and, finally, considerations for storing purified proteins are discussed.

Fabrication of Permeameter for Determination of Hydraulic Conductivity of Earth Materials

Laboratory investigation is one of the major ways of assessing soil hydraulic conductivity. Determination of hydraulic conductivity aids in engineering design of well pumping, prediction concerning spread of polluting fluids, embankment of canal bank affected by seepage, flooding solutions and stability of earth dams. However, different studies have shown that there are alternative models to Darcy’s law which governs the widely use of laboratory measurement of hydraulic conductivity. The deficiencies accustomed to the conventional permeameter such as the time wastage and cost-intensivehas led to different research modification. A low-cost permeameter was fabricated using a plastic column, hose pipe, to serve as water inlet and outlet connected to two manometer tubes to measure the pressure head difference. The hydraulic conductivities measured using the low-cost were 4.31 cm/s, 8.14 cm/s, 6.12 cm/s, 5.86 cm/s for 0.3 mm coarse sand, 0.85-1 mm fine sand, sandy clay and silty clay respectively. In comparison of the fabricated permeameter with conventional permeameter and other fabricated laboratory permeameters, it was observed that the hydraulic conductivity obtained is consistent with the typical permeability range for each soil type.

Lumbar Puncture: Creation and Resident Acceptance of a Low-Cost, Durable, Reusable Fluoroscopic Phantom with a Fluid-Filled Spinal Canal for Training at an Academic Program

Simulation-based medical training provides learners a method to develop technical skills without exposing patients to harm. Although fluoroscopic phantoms are already adopted in some areas of radiology, this has historically not been for lumbar puncture. Commercially available phantoms are expensive. We report a cost-effective, accessible solution by creation of an inexpensive phantom for resident training to perform fluoroscopically guided lumbar puncture, as well as instructions on how to make a phantom for residency education. An anthropomorphic ballistics-gel phantom that contains a plastic lumbar vertebral column and simulated CSF space was created. Radiology residents with minimum or no experience with fluoroscopically guided lumbar punctures were given a brief education and practiced fluoroscopically guided lumbar punctures on the phantom. A survey from the residents was then done. The phantom was qualitatively quite durable and deemed adequate for educational purposes. All the residents surveyed expressed the desire to have this phantom available and it increased comfort, knowledge, and perceived likelihood of success. Few articles have been published that focused on low-cost phantom creation for fluoroscopic-procedure training. This study supports the benefits of using phantoms for fluoroscopic training as well as step-by-step instructions for creation of this phantom. The residents responded positively and felt more confident in their fluoroscopically guided techniques. The ability to make a long-term training device for resident education would be inexpensive and relatively easy to implement in academic programs.

Collapse Mechanism of Strong Column Weak Beam Buildings of Varying Heights

During past earthquakes column plastic hinges are more important than beam hinges which gives rise to global structural damage and high life threatening risk. All the structural components transfers their forces through column and then column shares it with foundation to soil, so u can imagine if column fails whole structure can collapse this is strong beam weak column concept. In this paper collapse mechanism of three buildings 5, 12 and 15 storey heights are investigated for strong column weak beam concept. The structure is designed for zone 5 and medium soil. The aim of this work is to determine the static non-linear performance of three buildings of varying heights, each storey height is 3m and each bay width is 5m, the width of the building in X and Y direction is 20m. The heights of the buildings are 15m, 36m and 45m. The parameters which are obtained from the analysis are base shear, displacement and hinge formations in the structure. The base shear and displacement of the structures increases with an increase in strong column weak beam concepts. The hinge formations in the low-rise building involved beam failures where as the hinge formation in mid-rise buildings involves mixed failure pattern involving beams and columns.