Column Dimensions Research Articles

Effects of the central graphite column dimension and pebble size on power density distribution in annular core pebble‐bed HTR

Effects of the central graphite column dimension and pebble size on power density distribution in annular core pebble‐bed <scp>HTR</scp>

Model of retention time and density of gradient peak capacity for improved LC-MS method optimization: Application to metabolomics

A general and deterministic model is derived from the fundamentals of liquid chromatography to calculate retention time, peak width, peak capacity, and density of peak capacity in gradient liquid chromatography. The calculation of these chromatographic properties accounts for 1) the presence of initial (separation of the earliest eluters) and final (column wash) isocratic steps before and after the linear gradient, respectively, 2) the pre- (flow through needle and preheater tubes) and post-column (outlet and emitter tubes before MS detection) dispersion, 3) the compression of the chromatographic band, and 4) the retention of the organic modifier onto the RPLC column. The multiple and variable method parameters may include the column dimensions, particle size, flow rate, temperature, initial and final isocratic hold times, gradient time, gradient steepness, column conditioning/sample load time, and the pre- and post-column tube dimensions. The model enables the users to perform robust multi-dimensional optimization of UHPLC-MS methods and offers the possibility to predict the expected MS feature density for increased method performance. Method optimization can be further improved by matching the observed MS feature density (number of metabolites detected as function of time) to the predicted density of peak capacity. It is directly applied to the optimization of high-throughput RPLC separation methods specifically designed for large-scale urinary metabolic phenotyping.

Finite element analysis for interior slab-column connections reinforced with GFRP bars using damage plasticity model

This research article presents a numerical investigation of full interior connections reinforced with glass fiber reinforced polymer (GFRP) using the concrete damage plastic (CDP) model in ABAQUS software. The CDP model is initially verified by experimental results from the literature to achieve the optimum accuracy for parametric analysis. In addition, numerical results from calibration are compared against four international design codes and five empirical expressions proposed to estimate the punching shear capacity of GFRP-RC slab-column connections from the literature.Then, a numerical parametric study is performed by applying the calibrated CDP model to 324 large-scale GFRP-RC slab-column connections. The numerical investigation is then extended to assess the impact of various design parameters (i.e., the GFRP reinforcement ratio, slab depth, concrete strength, GFRP grade, and column dimensions) on the ductility index of the connections and compared with the same connections that are reinforced with conventional steel reinforcement.Finally, numerical investigation demonstrates the capability of the proposed CDP model to simulate and estimate the overall performance of the GFRP RC slab-column connections with good accuracy.

Discrete element model for the failure analysis of partially saturated porous media with propagating cracks represented with embedded strong discontinuities

A novel, fully coupled hydro-mechanical model for the failure analysis of partially saturated porous media is presented. Failure mechanisms pertain to propagating discontinuities, i.e. tensile cracks and shear bands influenced by matric suction or capillary pressure, that arises in the partially water saturated conditions. In order to simulate propagating discontinuities, a discrete model based on lattice domain representation is used, where embedded strong discontinuities serve for mesh objective propagation of discontinuities. The full coupling is provided with Biot porous media theory, Bishop effective stress concept and nonlinear Richards’s equation for the unsaturated fluid flow. The relation between suction and saturation state is given through the van Genuchten constitutive model. The capabilities of the model are presented with the three representative simulations. The first one is related to unsaturated flow in one dimensional sand column. The second one deals with mechanically influenced propagation of dilatant and compactive shear bands with the goal of examining how these mechanisms influence the pore pressure field, suction development and saturation state of the porous media. The third one explores the important geo-environmental engineering application in which development of tensile cracks is triggered and propagated by drying mechanism of the porous media, also known as desiccation cracking of soils.

A comparison of machine learning- and regression-based models for predicting ductility ratio of RC beam-column joints

Seismic response of Reinforced Concrete (RC) beam-column joints has always been evaluated by researchers due to their undeniable influence on the overall behavior of RC building frames under seismic loads. In the present study, an attempt has been made to predict displacement ductility ratio of RC joints using machine learning- (Artificial Neural Network and Random Forest) and regression-based (linear, nonlinear and ridge) methods. Therefore, a dataset including the results of over 170 experimental studies conducted on RC joints was collected from the international peer-reviewed publications. Parameters reflecting beam and column dimensions (length, cross section width and depth), reinforcement detailing (longitudinal and transverse reinforcement of beams and columns), material properties (concrete compressive strength, yield strength of longitudinal and transverse reinforcement) and retrofitting techniques were considered as input variables for predicting the only output parameter, displacement ductility ratio. The predicted and actual values were compared together and the efficiency of the models was assessed by Taylor diagram and performance metrics including RSME, MAE, MAPE and R2. The evaluation results proved the high reliability of proposed models for predicting ductility of RC joints.

Analytical Method Development and Validation for the Simultaneous Estimation of Rifampicin and Isoniazid in its Bulk and Pharmaceutical Dosage Forms by RP-HPLC

Background A combination of Rifampicin and Isoniazid is the drug of choice to treat tuberculosis patients in sustenance or those travelling to a region where there is a probability of being infected with tuberculosis.Objective The main objective of the simultaneous estimation of combined drug was to establish identity purity physical characteristics and potency of the drugs.Methodology The chromatographic environment was fortunately evolved for the partition of Rifampicin and Isoniazid by using column thermosil RPC18 4.5times100 nm 5.0 microm flow rate was 1 mLmin mobile phase ratio was 7030 vv methanolsodium acetate buffer. A pH of 3 was adjusted with Ortho phosphoric acid wavelength was detected at 240 nm. Column dimensions were Thermosil C184.6times100mm 5.0 microm.Results The results were in good agreement with those obtained with official HPLC with absorption maximum at 240 nm by preparing mobile phase 7030 methanolsodium acetate buffer with a flow rate 1 mLmin and it ran for 5 minutes by selecting thermosil RPC18 4.5times100 nm of ambient temperature. All the results obtained were precise accurate and robust as per international conference on Harmonization ICH guidelines.Conclusion It can be concluded that the proposed Reverse Phase High Performance Liquid Chromatographic RPHPLC method is accurate precise sensitive specific robust and reproducible for the simultaneous analysis of Rifampicin and Isoniazid with less tailing factor and is also economical. Thermosil RPC18 4.5times100 nm 5.0 microm flow rate was 1 mLmin. Both the samples were in the range of 200 to 400 nm and maximum wavelength was identified at 240 nm.

Flexural behavior of Two-Way voided slab

Slab is an essential part of a structure that consumes large quantity of concrete among all structural elements. Large self-weight of slab contrebutes to the larger dimensions of beams, columns & foundations which causes the increase in overall dead load and cost of structure. Voided slabs can be used as an economical and ecofriendly alternative to existing RCC slab systems. In voided slab concrete from the tension zone of the slab is removed partially; where concrete doesn’t have any structural benefit by creating voids using recycled plastic void formers. Therefore, self-weight of slab is decreased without changing the depth of slab, which in turns reduces the number of columns and offers more floor space for utilization. As it transfers lesser load on beams, columns & foundations, it reduces the overall sizes of all structural components and overall cost can be saved. In this study, finite element analysis is carried out using ANSYS Workbench 18.1. Five specimens are analyzed in this study out of which one of the slabs is a solid slab and the other four are voided slabs. Dice (cube) shaped voids are used as a void former in the biaxial voided slabs with variation in sizes and spacing between each other. The two-way flexural strength has been evaluated by applying sixteen point loading over full area of a slab. Load vs. deflection curves are plotted for each voided slab and compared it with solid slab. The flexural strength is evaluated using Rankine-Grashoff Theory and results are compared with the software results. The primary objective of the work is to study elastic behavior of voided slab and to compare it with solid slab. The present study proved that flexural behavior of voided slab with dice shaped void former shows good correlation with the solid slab system.

Strengthening capacity study of reinforced concrete school building structure in Banda Aceh toward earthquakes and tsunami hazards

Banda Aceh City was a high level areas of the earthquake and tsunami damage that occurred in 2004. Building damage prevention can be done by planning earthquake-resistant school building structures. The rebuilding needs to be reviewed for its capacity structure because of the high risk building location of earthquake and tsunami hazards. This study aims to determine the behavior and capacity of the school building structure using the earthquake and tsunami scenario in 2004 in Banda Aceh. Capacity analysis by column enlargement of the existing building is one of the research variables. Earthquake load refers to data from the Sumatera-Andaman earthquake on December 26, 2004 and tsunami load refers to FEMA P646. Two typical school buildings were taken from data recapitulation of 100 buildings survey, namely SDN 48 and SDN 8, which represented the overall typical school building in Banda Aceh. This study uses the pushover analysis method on the SAP2000 software. Based on the capacity curve, the value of displacement in the x-y directions in the existing building are greater than the column variation building at SDN 48 and SDN 8. While the shear force value in the existing building are smaller than the column variation building. This shows that with the addition of column dimensions, the cross-sectional area gets bigger and affects the capacity of the building structure.

Hydrodynamics of single bubble rising through water column using volume of fluid (VOF) method

The importance of air bubble dynamics in liquid is in some phenomena like chemical and biochemical processes in refinery units. The 2D Volume of Fluid (VOF) method together with the CFD technique were employed for simulating. The dynamic meshing technique is used to simulate the hydrodynamics of rising air bubble in liquid water column via the User Defined Function (UDF) code in the C++ environment was developed to evaluate bubble rising through the water column. The rising of air bubble through a stagnant water column has been considered and the influence of column dimension, bubble size, and aspect ratio on the rising velocity characterized is investigated. The obtained results showed that the bubble rising velocity increase with the bubble size and its shapes was transformed from ellipsoidalto-ellipsoidal cap shape. The rising velocity of air bubbles was affected by the column diameter. It was observed that the air bubble moving toward the top of the water column with oscillation for all cases. A good agreement was obtained between the rising velocity predicted in the simulation with that obtained from the literature.

KELAIKAN BANGUNAN FASILITAS UMUM UNTUK TEMPAT EVAKUASI TSUNAMI DI KECAMATAN BAITUSSALAM

Tsunami evacuation buildings in the tsunami-prone zone area are essential to minimize the number of fatalities. The purpose of this study is to analyze the behavior of the existing building structures caused by earthquake and tsunami loads in the Baitussalam District. The existing buildings that were reviewed were the SD 1 Lambada Klieng Building and the Syahamah Aceh Putra Foundation Building. The methodology in determining the capacity of the existing structures by conducting a field assessment to obtain data on existing buildings which will then be modeled, both existing buildings and a potential design of buildings using structural analysis software. for analysis. The results of the analysis show that the existing buildings need to be strengthened and redesigned to be able to withstand the effects of earthquake and tsunami loads. The remodeled of the buildings included modifying the column dimensions and also additional building stories. The remodeled of the existing building structures to become the tsunami evacuation structures is safe enough against earthquake loads and tsunami loads that occur.

Analytical Method Development and Validation for Estimation of Mifepristone in Pure and Pharmaceutical Dosage Form

Mifepristone structurally belongs to the class of anti-progesterone steroids, which are used as an oral contraceptive. The reverse phase HPLC method was designed in a simplified and rapid way for the estimation of Mifepristone in bulk as well as tablets. The method was established using a Kromasil C18 column of dimensions of 250mm×4.6mm and a particle size of 5m.The used mobile phase was Acetonitrile: Water (70:30, v/v). The pump was pumped at 1 ml/min at a temperature of about 30 ± 2 °C and the eluted analyte was identified at 305 nm. Mifepristone eluted with a mean retention time of 6.27 minutes. The intended method was validated as per ICH (International Council for Harmonisation) guidelines, indicating a high degree of specificity, system suitability, accuracy, precision, and robustness. The LOD (Limit of detection) was found to be 0.7238 ppm and the limit of measurement was 0.9562 ppm. The method linearity was found to be between 1-6µg/ml, with an R2 of 0.9923. In accuracy studies, the percent recovery was found to be between 99.39% - 100.50%. The method was discovered to be precise as the values of the percent RSD were found to be less than 2.0% for both intraday and interday. The method was discovered to be reliable and robust. Mifepristone in marketed pharmaceutical tablet dosage form was effectively quantified using the established Reverse Phase HPLC method.

N-Alkylpyridinium sulfonates for retention time indexing in reversed-phase-liquid chromatography-mass spectrometry–based metabolomics

Chromatographic retention time information is valuable, orthogonal information to MS and MS/MS data that can be used in metabolite identification. However, while comparison of MS data between different instruments is possible to a certain degree, retention times (RTs) can vary extensively, even when nominally the same phase system is used. Different factors such as column dead volumes, system extra column volume, and gradient dwell volume can influence absolute retention times. Retention time indexing (RTI), routinely employed in gas chromatography (e.g., Kovats index), allows compensation for deviations in experimental conditions. Different systems have been reported for RTI in liquid chromatography, but none of them have been applied to metabolomics to the same extent as they have with GC. Recently, a more universal RTI system has been reported based on a homologous series of N-alkylpyridinium sulfonates (NAPS). These reference standards ionize in both positive and negative ionization modes and are UV-active. We demonstrate the NAPS can be used for retention time indexing in reversed-phase-liquid chromatography-mass spectrometry (RP-LC–MS)–based metabolomics. Having measured >500 metabolite standards and varying flow rate and column dimension, we show that conversion of RT to retention indices (RI) substantially improves comparability of retention information and enables to use of RI for metabolite annotation and identification.Graphical

Development and validation of an analytical method for the determination of related substances in bisoprolol fumarate in dosage forms by HPLC-UV-DAD

The aim of this work was the development of an efficient analytical method for the determination of bisoprolol and related substances in the finished drug product using HPLC/DAD. Different bonded phases (alkyl and phenyl) with variable pore sizes and column dimensions, temperatures, and mobile phases with variable pH and additives were tested. Experiments that included using Hypersil 3 BDS C18 100 × 4 mm, 3 mm; Zorbax SB C18 150 × 4.6 mm, 3.5 mm; Acquity UPLC BEH C18 50 × 2.1 mm, 1.7 mm; and Xterra MS C18 100 × 4.6 mm, 3.5 mm gave the best results when considering the separation and resolution of the tested analytes within a reasonable run time. The method using Xterra MS C18 100 × 4.6 mm, 3.5 mm was validated as the most suitable when taking into account the mobile phase preparation and versatility, analysis time, and equipment maintenance.Validation parameters (linearity, accuracy, precision, selectivity) confirmed the method as suitable for its intended use.

Phenomics-Assisted Selection for Herbage Accumulation in Alfalfa (Medicago sativa L.).

The application of remote sensing in plant breeding is becoming a routine method for fast and non-destructive high-throughput phenotyping (HTP) using unmanned aerial vehicles (UAVs) equipped with sensors. Alfalfa (Medicago sativa L.) is a perennial forage legume grown in more than 30 million hectares worldwide. Breeding alfalfa for herbage accumulation (HA) requires frequent and multiple phenotyping efforts, which is laborious and costly. The objective of this study was to assess the efficiency of UAV-based imagery and spatial analysis in the selection of alfalfa for HA. The alfalfa breeding population was composed of 145 full-sib and 34 half-sib families, and the experimental design was a row-column with augmented representation of controls. The experiment was established in November 2017, and HA was harvested four times between August 2018 and January 2019. A UAV equipped with a multispectral camera was used for HTP before each harvest. Four vegetation indices (VIs) were calculated from the UAV-based images: NDVI, NDRE, GNDVI, and GRVI. All VIs showed a high correlation with HA, and VIs predicted HA with moderate accuracy. HA and NDVI were used for further analyses to calculate the genetic parameters using linear mixed models. The spatial analysis had a significant effect in both dimensions (rows and columns) for HA and NDVI, resulting in improvements in the estimation of genetic parameters. Univariate models for NDVI and HA, and bivariate models, were fit to predict family performance for scenarios with various levels of HA data (simulated in silico by assigning missing values to full dataset). The bivariate models provided higher correlation among predicted values, higher coincidence for selection, and higher genetic gain even for scenarios with only 30% of HA data. Hence, HTP is a reliable and efficient method to aid alfalfa phenotyping to improve HA. Additionally, the use of spatial analysis can also improve the accuracy of selection in breeding trials.

Column length is a structure-independent measure of solvent consumption in liquid chromatography

Column length (L) is a measure of solvent consumption in LC analysis. In its latter role, L is the specific solvent consumption – the void time (tM) solvent consumption per unit of the column flow-area (AF) which is the cross-sectional area of the column open space (external and internal pores). In tanal-long LC analysis (isocratic or gradient), the solvent consumption (VS) is VS = AFLtanal /tM regardless of flow rate (F) as long as all changes in column dimensions and operational parameters are translatable (in gradient analysis, the ratio of the gradient time (tG) to tM remains fixed).

Stability-indicating method development and validation for the concurrent determination of darunavir, cobicistat, emtricitabine and tenofovir alafenamide by UPLC in bulk and tablet dosage forms

BackgroundTablet dosage forms containing combination of darunavir a protease inhibitor, cobicistat a cytochrome P450 3A inhibitor, emtricitabine and tenofovir alafenamide which were nucleoside reverse transcriptase inhibitors were approved by USFDA on 1st July 2018 to suppress the viral load in HIV patients. It can be used as a complete regimen for the treatment of HIV-1 infection in adults and paediatric patients weighing at least 40 kg. An UPLC method was developed, and separation was done on SB C8 column of dimensions 50 × 2.1 × 1.8 μ with mobile phase 0.01 N potassium dihydrogen ortho phosphate (pH-4.8) and acetonitrile in 60:40 ratio, at a flow rate of 0.3 mL/min and an injection volume of 2 μL. The column temperature was maintained at 30 °C, and detection wavelength was 267 nm. The method was validated according to ICH guidelines.ResultsThe retention times were 1.031, 1.341, 1.630 and 2.153 min, and they were linear in the concentration range of 1.25–7.5 μg/mL, 18.75–112.5 μg/mL, 25–150 μg/mL and 100–600 μg/mL for tenofovir alafenamide, cobicistat, emtricitabine and darunavir, respectively. The intraday and interday precisions were found to be within acceptable limits. LOD was found to be 0.06 μg/mL, 0.51 μg/mL, 1.31 μg/mL and 3.01 μg/mL, and LOQ was 0.19 μg/mL, 1.54 μg/mL, 3.96 μg/mL and 9.13 μg/mL for tenofovir alafenamide, cobicistat, emtricitabine and darunavir. The correlation coefficients were found to be more than 0.999, and recovery was more than 99.52% indicating the method was accurate. Forced degradation studies reveal that the drugs are unstable under acidic conditions. The method was simple, accurate, precise, stable and can be analysed in less runtime of 4 min.ConclusionsThe flexibility, accuracy and precision of the developed method ensure its applicability in routine analysis of tablet dosage forms.Graphical

PERENCANAAN GEDUNG PARKIR MOBIL TIGA LANTAI DENGAN MENGGUNAKAN STRUKTUR BETON DI AREA DEPO MRT JAKARTA

The Jakarta MRT depot is experiencing increasing development. Currently, the car park area at the Jakarta MRT Depot is not functioning properly due to the lack of available land, so that many four-wheeled vehicles are parked inappropriately. To overcome these problems, it is necessary to build a car parking area at the Jakarta MRT Depot. The plan is to build a parking building with an area of 6,656 m2, a parking angle design of 90°, a reinforced concrete structure consisting of two floors. The beam dimensions are 650 mm x 500 mm, the column dimensions are 500 mm x 500 mm and the plate thickness is 200 mm. The parking building can accommodate as many as 400 four-wheeled vehicles. In planning the car park building, data are used, including the results of ground sondir. Analysis of calculations using the SAP2000 Version20 design and structure application.

Capillary hysteresis and gravity segregation in two phase flow through porous media

We study the gravity driven flow of two fluid phases in a one dimensional homogeneous porous column when history dependence of the pressure difference between the phases (capillary pressure) is taken into account. In the hyperbolic limit, solutions of such systems satisfy the Buckley-Leverett equation with a non-monotone flux function. However, solutions for the hysteretic case do not converge to the classical solutions in the hyperbolic limit in a wide range of situations. In particular, with Riemann data as initial condition, stationary shocks become possible in addition to classical components such as shocks, rarefaction waves and constant states. We derive an admissibility criterion for the stationary shocks and outline all admissible shocks. Depending on the capillary pressure functions, flux function and the Riemann data, two cases are identified a priori for which the solution consists of a stationary shock. In the first case, the shock remains at the point where the initial condition is discontinuous. In the second case, the solution is frozen in time in at least one semi-infinite half. The predictions are verified using numerical results.

Unified correlations for the prediction of the slip velocity, characteristic velocity, flooding throughput and flooding slip velocity in a pulsed disc and doughnut extraction column

Pulsed disc and doughnut columns (PDDC) have become an integral part of the nuclear fuel reprocessing and hydrometallurgical industries for quite some time. In this study, five unified correlations have been proposed for the prediction of slip velocity, characteristic velocity, flooding throughput and flooding slip velocity over a wide range of operating parameters, column dimensions and chemical systems in a PDDC. Before formulation of the correlations, a detailed cross validation of the existing correlations with the reported and the present experimental results have been performed. Then the empirical equations have been formulated by correlating the reported results by various researchers along with the present experimental data. The total number of data points used for predicting the slip velocity, characteristic velocity, flooding throughput and flooding slip velocity is 584, 129,185 and 128, respectively. For slip velocity and slip velocity at flood point, two new correlations have been proposed. For characteristic velocity and flooding throughput, the reported and the present data points have been refitted using existing correlations. Good accuracy has been achieved between the predicted and experimental results.

Study on progressive collapse resistance and mechanisms of beam-column sub-assemblages

Compressive arch action (CAA) and tensile catenary action (TCA) are the main resistance mechanisms against progressive collapse in reinforced concrete (RC) buildings. When the lateral constraints of beams are strong enough, CAA and TCA could be developed and obtain significant additional progressive collapse resistance. Lateral constraints of beams are key parameters affecting the CAA and TCA capacities. For a frame under a middle column lost scenario, the adjacent columns can carry much more loads than designed. Whether the adjacent column could provide adequate lateral constraints to beams need to be examined. Therefore, this article selected beam-column substructures as the research objects. Firstly, a new division method on resistance mechanisms was proposed considering the contributions of each action. Then a model of the beam-column substructure was established and verified with ABAQUS software. The effects of different lateral constraints and beam height on CAA and TCA capacities were investigated by changing the column dimensions and beam heights. Finally, a new theoretical model for predicting the BM capacity, CAA capacity, and TCA capacity of beam-column substructures under different lateral constraints was established. The interaction between the column and beam and the parameters of columns and beams are taken into consideration.