Column Dimensions Research Articles

Experimental Study and Direct Strength Method for Cold-Formed Steel Built-Up I-Sectional Columns under Axial Compression

The objective of this paper is to investigate the buckling behavior and design method of the ultimate strength for the cold-formed steel (CFS) built-up I-sectional columns under axial compression which failed in distortional buckling and interactive buckling. A total of 56 CFS built-up I-sectional columns subjected to axial compression were tested, and the different buckling modes and ultimate strengths were analyzed in detail by varying the thickness, the length, the spacing of screws, the end fastener group, and the cross-sectional dimensions of CFS built-up I-sectional columns. It was shown in the test that noticeable interaction of local and distortional buckling or interaction of local, distortional, and global buckling was observed for the built-up I-sectional columns with different lengths and cross-sectional dimensions. A finite element model (FEM) was developed and validated with experimental results. A further parametric study has been conducted including different cross sections and slenderness ratios for the built-up I-sectional columns. The load-carrying capacities obtained from the experimental and numerical study were used to investigate the feasibility of the current direct strength method (DSM) when DSM was applied to CFS built-up I-sectional columns. The comparison results showed that the current DSM is not safe for CFS built-up columns failed in distortional buckling and interactive buckling. Therefore, the improved design formulas were proposed, and their accuracy was verified by using finite element analysis (FEA) and experimental results of CFS built-up I-sectional columns subjected to axial compression.

Modelling bed dimension for fluidized bed chemical vapour deposition

The present paper introduces a simple analytical model to predict the bed dimension of a continuous FBCVD (fluidized bed chemical vapour deposition) process. The expressions for column diameter and bed height were determined based on the target production rate, yield, conversion of the feed gas and gas volume change in the system. The model proposed in this article suggests that the diameter of an FBCVD column has to be reduced to enhance the conversion at a given production rate. To avoid linear expansion of the column diameter upon scale-up, the conversion or the superficial velocity of the feed gas has to increase, which results in an increase in the bed height. On the basis of the proposed model, a reasonable preliminary column dimension can be outlined when only a limited number of process parameters are available. CPFD (computational particle fluid dynamics) simulation results are presented to verify the model.

In Vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

Validated Stability Indicating Method for Determination of Indapamide in Pharmaceutical Formulation

A stability indicating method for Indapamide in an oral antihypertensive tablet and bulk dosage forms was developed and validated by reverse phase HPLC (RP-HPLC). The proposed RP-HPLC Shisheido Capcell Pak C18 column was used and column dimension was 250mm × 4.6mm i.d., 5μm partical size at ambient temperature. The mobile phase Methanol and Phosphate Buffer pH 5.8 (60:40) was run in isocratic mode at a flow rate of 1.0ml/minute. The wavelength of Indapamide was selected at 241nm. Indapamide was found as single peak in the chromatogram at 6.58 min. The different chromatographic conditions were applied to determine the drug in pharmaceutical dosage form. The linearity of the proposed method was found in a range of 0.2-1.2μg/ml with coefficient of correlation (r2) value 0.999, slope 8360 and intercept -77.78. The percent RSD of intraday precision and interday precision were found in range of 0.498 - 1.661 and 0.882 - 1.623 respectively. The average accuracy of the method at three different levels of 50, 100 and 150 % were found to be 100.67, 99.50 and 100.65, respectively. The LOQ and LOD expressed as signal to noise ratio (S/N) were found to be 0.03 and 0.08μg/mL with good accuracy and precision. Indapamide was exposed to different stress conditions like alkaline, acidic, thermal, oxidative and photolytic. The stressed samples were analyzed by the proposed method. The proposed methods can be used for routine analysis stability testing and assay of Indapamide in quality control laboratories.

Predication of the residual axial load capacity of CFRP-strengthened RC column subjected to blast loading using artificial neural network

In this study, two genetic algorithm optimized backpropagation neural networks (GA-BPNN) were established to predict the ratio of residual axial load capacity to the maximum axial load capacity (referred to as RCI hereafter) of the non- and CFRP-strengthened RC columns based on a huge amount of simulation data. The first one can be used to predict the residual axial load capacity of the damaged non- and CFRP-strengthened RC columns induced by blast load with the input of several parameters including column dimensions, concrete strength, transverse reinforcement ratio, longitudinal reinforcement ratio, axial load ratio, CFRP stiffness, carbon fiber strength, peak pressure and impulse of the blast load. Therefore it can be used for the blast-resistant design of non- and CFRP-strengthened RC columns. The input variables of the second GA-BPNN were changed to be the ratio of residual mid-height deflection to the column height after the explosion, column dimensions, concrete strength, transverse reinforcement ratio, longitudinal reinforcement ratio, CFRP stiffness and carbon fiber strength. Since the input variables of the second GA-BPNN could be easily derived after the explosion, thus it could be used for the rapid damage assessment of RC columns. Damage assessments for three non- and CFRP-strengthened columns were also conducted using the first GA-BPNN.

A novel and sensitive method for determination of amisulpride in human plasma by two-dimensional liquid chromatography.

A novel and sensitive heart-cutting two-dimensional liquid chromatography with ultraviolet detection method (2D-LC-UV) was developed and validated for determination of amisulpride in human plasma. The 2D-LC system consists of a first dimensional (1 D) LC column and a middle transfer column as well as a second-dimensional (2 D) LC column. After simple protein precipitation, the sample was directly injected into the introduction valve of the 2D-LC system. The 1 D column, playing a role of primary separation and preconcentration for complex plasma matrices, transferred the targets to the intermediate column. Following capture of targets on the middle column online, the analytes were transferred to the 2 D separation column by a six-port valve. The 2 D column, avoiding interference from the plasma matrix, completed further separation and quantification. An assistant pump was optimized for primary enrichment as well as final elution in the heart-cutting mode. The analytical time of amisulpride was 7.401 min. The accuracy was between 0.48 and 8.49%, while the intra- and inter-day precisions ranged from 0.9 to 3.1% and from 1.7% to 3.3%, respectively. The linear range of amisulpride was 48.15-2,407.59 ng/ml, while the extraction recovery was 98.7-101.3%. The strategy established in the study, which was successfully applied to therapeutic drug monitoring of amisulpride for routine clinical detection, displays high sensitivity, good repeatability, convenience and low cost.

Effect of using column capital on the punching shear strength of flat slab-edge column connection under eccentric loading

The influence of column capital on punching resistance at the edge column is virtually not fully studied. This is a significant omission, as column capital under eccentric loading can arise in flat slab buildings under lateral loading from wind and earthquakes. This paper deals with the effect of using reinforced concrete column capital on the punching shear strength of the flat slab-edge column connection under eccentric loading. The study involves testing experimentally six reinforced concrete flat slab-edge column models with dimensions (1000×1600×100 mm) with two different dimensions of column capital (300×400 mm, and 500×800 mm) in addition to reference model without columns capital (column dimension 200×200mm). Two specimens as a control without columns capital where the first specimen under axial load according to column section but another under eccentric loading with eccentricity (e=half width of column). The effect of size of the column capital and were studied experimentally. We observed an increase in punching resistance by (17.02% and 27.66%) respectively over that of the reference specimen under axial load, and about (18.18% and 25%) respectively over that of the reference specimen under eccentric loading.

Considerations on the dimensioning of columns with dimensions less than that established by NBR 6118 (ABNT, 2014)

The search for methods that provide savings greatly drives the search for alternatives when it comes to cost reduction. The obsession with aesthetics and cheaper alternatives for civil construction, can lead to unexpected and dangerous results. The reduction of the dimensions of the columns can be done consciously, always keeping in mind the compliance with normative standards combined with structural optimization. The objective of this work was to evaluate the efforts resulting from the reduction of the minimum dimensions beyond that established by NBR 6118 (ABNT, 2014) and compare with the considerations of NBR 15575 (ABNT, 2013) about a possible permission to reduce the minimum dimensions of columns. For this, the software MathCAD, Eberick and SAP2000 were used to implement the calculation and design methods of the columns. The variables evaluated were the steel area of ​​columns with different cross sections, length of buckling and the necessary anchoring length that a beam would need to anchor in the columns. As a result, it was found that in relation to the steel area, the decrease in the section resulted in increases in the steel area. The buckling was not acceptable (λ> 140) with a cross-section column less than 19 cm for situations of double height up to 6 m in height, according to NBR 15575 cites. The criterion of anchoring the beam reinforcement in a column with section smaller than 14 cm was not feasible for all situations.

Sequential injection analysis coupled to on-line benchtop proton NMR: Method development and application to the determination of synthetic cathinones in seized drug samples

Synthetic cathinones are a class of new psychoactive substances (NPS), an emerging group of analogues to traditional illicit drugs which are functionalized to circumvent legal regulations. The analytical investigation of NPS by traditional methods, such as gas chromatography-mass spectrometry (GC-MS), is challenging because newly emerging NPS may not yet appear in spectral libraries and because of the inability to determine certain positional isomers. Low-field or “benchtop” proton nuclear magnetic resonance spectroscopy (NMR) is an alternative that provides significant qualitative information but is particularly susceptible to matrix interferences. To this end, the development of a Sequential Injection Analysis (SIA) method which uses solid-phase extraction (SPE) to remove interfering matrix components prior to NMR determination is described. Factors including the type of SPE sorbent, column dimensions, and sample loading and elution conditions were examined. Several cathinone simulants (primary, secondary, and tertiary amines), “DEA exempt” cathinone standards, as well as authentic case samples were studied. The selectivity of the SIA-NMR-UV method was investigated against a broad range of “cutting agents” and was found to successfully remove all compounds tested with the exception of other basic drugs (e.g., acetaminophen). The limit of detection and reproducibility of the method were optimized using a Plackett-Burman screening design and Sequential Simplex optimization. Using a UV detector for dual (in series) quantification, the multivariate-optimized method produced a method limit of detection (3σ) for the cathinone simulant Phenylpropanolamine (PPA) of 23 μmol L−1, and a calibration model, in terms of UV peak area, of Area = 0.19 [PPA, mmol L−1] – 0.04. The optimized method generated ~2 mL of waste per day, and had a footprint of ~1 m2 Finally, the multivariate-optimized SIA-NMR-UV method was successfully applied to several more case samples and the cathinones were definitively identified.

Analytical Stress-Strain model for BFRP strengthened RC columns under axial loading

Reinforced column with external wrapping of FRP (Fiber Reinforced Polymer) is one of the strengthening methods. The objective of this experimental work is to determine the axial stress and strain capacity of BFRP (Basalt Fiber Reinforcement Polymer) strengthened RC columns (Reinforced Concrete) under axial loading. The dimension of RC square cross section column 100 mm × 100 mm with λ = 10 (slenderness ratio) and RC circular column of diameter 150 mm with λ = 6.67 (slenderness ratio) are externally strengthened by BFRP layers as per the ACI 440.2R-8 code. All the columns are casted at the depth of 1000 mm. The parameters studies are, shape of the columns (square and circular) and number of BFRP layers (one, two and three). Result discussed about the unconfined and BFRP confined RC columns stress–strain response, deformation control, lateral confining pressure and cost analysis. It is concluded that the RC short circular column confined with BFRP three layers offer more resistance to buckling and has greater load carrying capacity than that of the unconfined circular column and BFRP confined square columns. The ultimate stress and strain equations were predicted from the trend line drawn for BFRP strengthened RC square and circular columns.

Subspace estimation from unbalanced and incomplete data matrices: ℓ2,∞ statistical guarantees

This paper is concerned with estimating the column space of an unknown low-rank matrix A⋆∈Rd1×d2, given noisy and partial observations of its entries. There is no shortage of scenarios where the observations—while being too noisy to support faithful recovery of the entire matrix—still convey sufficient information to enable reliable estimation of the column space of interest. This is particularly evident and crucial for the highly unbalanced case where the column dimension d2 far exceeds the row dimension d1, which is the focal point of the current paper. We investigate an efficient spectral method, which operates upon the sample Gram matrix with diagonal deletion. While this algorithmic idea has been studied before, we establish new statistical guarantees for this method in terms of both ℓ2 and ℓ2,∞ estimation accuracy, which improve upon prior results if d2 is substantially larger than d1. To illustrate the effectiveness of our findings, we derive matching minimax lower bounds with respect to the noise levels, and develop consequences of our general theory for three applications of practical importance: (1) tensor completion from noisy data, (2) covariance estimation/principal component analysis with missing data and (3) community recovery in bipartite graphs. Our theory leads to improved performance guarantees for all three cases.

Unraveling the Complex Olefin Isomer Mixture Using Two-Dimensional Gas Chromatography-Photoionization-Time of Flight Mass Spectrometry

Commercial dodecenes are a complex chemical mixture with a majority of C12 olefins and minority of C8-18 olefins. Structurally, dodecene products may consist of straight-chain alkenes, branched alkenes, as well as cyclic hydrocarbons. Due to the difference of feeds and catalysts used in the oligomerization reaction, the composition of the dodecenes is complex and their properties are very different. Knowing the complex composition of dodecenes can help tune the production process and select the appropriate products according to their end use. To reveal the complex profile of dodecenes, an analytical method using two-dimensional gas chromatography (GC×GC) coupled photoionization (PI) - time of flight mass spectrometry (TOFMS) was developed in this study. A conventional (nonpolar × polar) column combination (non-polar column as 1st dimension and mid-polar column as 2nd dimension) was selected. The analytical condition of GC was optimized using fractional factorial experimental design (DoE). Olefin congener grouping by carbon chain length and double bond equivalent (DBE) was achieved based on the detection of molecular ions by PI-TOFMS. Grouping of dodecenes by linear, mono-branched, di- and tri-branched subgroups was achieved based on branching index (BI) under the assumption of no retention time (RT) overlap among subgroups. Certain dodecene isomers were identified by retention index (RI) and further confirmed by PI mass spectra. The information altogether provided a multimodal characterization possibility to be used with statistical tools. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) of seventeen dodecene samples explained the composition variance between catalysts solid phosphoric acid and zeolite, as well as between feeds with C4 and without C4.

EVALUATION OF SEKOLAH ISLAM TERPADU (SIT) ALIYA BOGOR BUILDING STRUCTURE SYSTEM BASED ON THE REQUIREMENTS OF SNI 2847:2019

<p class="ListParagraph1">Sekolah Islam Terpadu (SIT) Aliya Bogor is located in west Bogor district, Bogor city, West Java, was founded in 200, thus the standards used by planning consultant in building planning using old standard, where these standards have been updated with current standard, namely SNI 2847:2019. The evaluation carried out in this study based on requirements SNI 2847:2019 knowing the outcome of building that was said to be safe used help software ETABS) and SpColumn. Length of building of Umar Bin Khatab A and B are 18,60 meter;23,65 meter.Building area of building Umar Bin Khatab A and B are 541,26 m<sup>2</sup>; 865,59 m<sup>2</sup>. Concrete quality assessment (fc’) that came from the test of hammer test column elements, beam elements, and plate elements as big 23,74 Mpa;26,59 Mpa;26,59 Mpa. After analysis some of to experience overstrength. The original column dimension In Building of Umar Bin Khatab A was K25x25 with shear reinforcement is Ø16-150 enlarge to K40x40 with shear reinforcement is Ø39-150 and beam dimension 20x40 enlarge to 35x55. On the building of Umar Bin Khatab B was K25x25 with shear reinforcement Ø16-150 enlarge to K40x40 with shear reinforcement Ø25-150, with the original beam dimension 20x40 enlarge to 30x55. The cost budget in the building of Umar Bin Khatab A is Rp 74.158.600,00 and in building of Umar Bin Khatab B is Rp 61.084.600,00.</p>

Investigation of the limit of discovery using tile-based Fisher ratio analysis with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) is followed by tile-based Fisher ratio (F-ratio) analysis to investigate the “limit of discovery” for low concentration levels of sulfur-containing compounds in JP8 jet fuel. A mixture of 14 sulfur-containing compounds was spiked at 30 ppm, 15 ppm, 3 ppm and 1.5 ppm into the neat fuel prior to GC×GC-TOFMS analysis with a “reversed” column format (aka polar first dimension (1D) and non-polar second dimension (2D) column). Prior standard implementation of tile-based F-ratio analysis utilized an average F-ratio requiring a minimum of 3 mass channels (m/z) with the highest F-ratios. Herein, we explore the notion that use of the top F-ratio m/z for hitlist ranking is superior to the standard implementation for analytes near their limit-of-quantitation (LOQ), defined as an analyte concentration that produces a signal equal to ten times the standard deviation of the baseline noise (10σn). Hitlist ranking comparisons revealed that using only the top F-ratio m/z resulted in impressive improvements in discoverability for the low concentration comparisons. Specifically, for the 3 ppm versus neat hitlist, 1,4-oxathiane (LOQ = 2.5 ppm) improved from hit 114 via standard F-ratio analysis, to hit 25. For the 1.5 ppm versus neat hitlist, 2-propylthiophene (LOQ = 0.64 ppm) improved from hit 59 to 17, benzo[b]thiophene (LOQ = 1.1 ppm) from hit 98 to 28, and 2,5-dimethylthiophene (LOQ = 1.3 ppm) from hit 262 to 39. Additional hitlist ranking comparisons revealed the importance of proper tile size selection, as analyte discoverability deteriorated upon using either an inappropriately too small or too large of a tile.

PERENCANAAN STRUKTUR GEDUNG HOTEL TOPAN PAKIS MALANG

The Topan Pakis Hotel Malang building has a building area of ± 1,600 m2 consisting of 4 floors, which is located on Jalan Raya Pakis Kembar, Pakis, Kota Malang. having a strategic location close to Abdul Rahman Saleh Airport, the land is very suitable to be built by a hotel. The purpose of this thesis is to plan upper structure that is safe and efficient in cost. Data needed is location plans, shop drawings of the building, and HSP Malang 2019. building modeling use the AutoCAD program. Planning of the upper structure which includes beams, columns, and plates refers to SNI 2847: 2013. And then the loads refers to PPIUG 1983. The quality of concrete used is 30 MPa for columns and 25 MPa for beams and plates, while the quality of rebar steel used is 400 MPa for columns and 240 MPa for beams and plates. SAP 2000 v14 application is used to calculate the force in a building. The calculation of the budget plan refers to the results of the upper structure planning. The results of this Hotel Topan Building planning are 12 cm plate thickness using Ø13 rebar steel, beam dimensions are 25/40 cm using D22 and D25 rebar steel, Ø10 stirrup, column dimensions 40/50 cm using D25 rebar steel and Ø10 stirrup. The calculation of the upper structure budget plan obtained value of Rp. 3,411,000,000.

Detailed numerical study of the peak shapes of neutral analytes injected at high solvent strength in short reversed-phase liquid chromatography columns and comparison with experimental observations

We report on a numerical investigation of the different steps in the development of the spatial concentration profiles developing along the axis of a liquid chromatography column when injecting large relative volumes (>10 to 20% of column volume) of analytes dissolved in a high solvent strength solvent band as can be encountered in the second dimension (2D) column of a two-dimensional liquid chromatography (2D-LC) system. More specifically, we made a detailed study of the different retention and the axial band broadening effects leading to the double-headed peak shapes or strongly fronting peaks that can be experimentally observed under certain conditions in 2D-LC. The establishment of these intricate peak profiles is discussed in all its fine, mechanistic details. The effect of the volume of the column, the volume and the shape of the sample band, the retention properties of the analyte and the band broadening experienced by the analytes and the sample solvent are investigated. A good agreement between the simulations and the experimental observations with caffeine and methylparaben injected in acetonitrile/water (ACN/H2O) mobile phase with different injection volumes is obtained. Save the difference in dwell volume, key features of experimental and simulated chromatograms agree within a few %. The simulations are also validated against a number of simple mathematical rules of thumb that can be established to predict the occurrence of a breakthrough fraction and estimate the amount of breakthrough.

Effect of beam and column dimensions on the behavior of RC beam-column joints

In the current study, the influence of beam and column dimensions on the seismic response of joints is numerically evaluated by changing beam and column dimensions in ABAQUS. Three wide column-beam joints were modeled and verified using the experimental studies available in the literature. Dimensions of verified models were then changed to evaluate the effect of element dimensions on the parameters including ultimate moment, ultimate shear and ultimate rotation. Variable parameters were the ratio of column width to beam width, Cw/Bw, the ratio of beam width to beam height, Bw/Bh, and ρ of column. It was concluded that by decreasing the ratio of Cw/Bw, both of ultimate moment and ultimate shear decreased. Additionally, by increasing the ratio of Bw/Bh, both of the ultimate moment and ultimate shear fluctuated. Moreover, by increasing ρcolumn, ultimate moment fluctuated, whilst ultimate shear increased. It was also indicated that by changing the variable parameters, ultimate curvature fluctuated.

Dynamic vulnerability assessment and damage prediction of RC columns subjected to severe impulsive loading

Reinforced concrete (RC) columns are crucial in building structures and they are of higher vulnerability to terrorist threat than any other structural elements. Thus it is of great interest and necessity to achieve a comprehensive understanding of the possible responses of RC columns when exposed to high intensive blast loads. The primary objective of this study is to derive analytical formulas to assess vulnerability of RC columns using an advanced numerical modelling approach. This investigation is necessary as the effect of blast loads would be minimal to the RC structure if the explosive charge is located at the safe standoff distance from the main columns in the building and therefore minimizes the chance of disastrous collapse of the RC columns. In the current research, finite element model is developed for RC columns using LS-DYNA program that includes a comprehensive discussion of the material models, element formulation, boundary condition and loading methods. Numerical model is validated to aid in the study of RC column testing against the explosion field test results. Residual capacity of RC column is selected as damage criteria. Intensive investigations using Arbitrary Lagrangian Eulerian (ALE) methodology are then implemented to evaluate the influence of scaled distance, column dimension, concrete and steel reinforcement properties and axial load index on the vulnerability of RC columns. The generated empirical formulae can be used by the designers to predict a damage degree of new column design when consider explosive loads. With an extensive knowledge on the vulnerability assessment of RC structures under blast explosion, advancement to the convention design of structural elements can be achieved to improve the column survivability, while reducing the lethality of explosive attack and in turn providing a safer environment for the public.

Uniform deformation design of outrigger braced skyscrapers: A simplified method for the preliminary design stage

A stiffness-based method for the preliminary design of outrigger braced skyscrapers is proposed. The method is founded on the concept of uniform distribution of deformation. This approach originates from the minimum-compliance optimization, in which the stiffest layout for the structure is sought for a given amount of material. Design variables include: the flexural stiffness of the core structure, the outrigger-belt elevation, and the peripheral column dimensions. These parameters are specified by requiring the curvature to be kept constant, yet minimum, as long as the allowable stress and displacement constraints are imposed. The resulting procedure is presented through a simplified hand-calculation algorithmic framework, which may be used during the preliminary design stage to estimate the size of elements and to give an initial assessment of the structural behavior. In order to show the practical application of the proposed method, a structure equipped with one outrigger is designed using the proposed algorithm. The comparative analysis of the results reveals that the presented method provides a rather high degree of accuracy in practice.

Correlations for predicting heat transfer coefficients in bubble columns

Knowledge of the heat transfer coefficients in bubble columns can offer valuable references for the design and scale-up of reactors. This work aims to develop reliable correlations that can be applied in precisely predicting the global and local heat transfer coefficients in air-water or air-water-glass beads bubble columns. The influence of superficial gas velocities, column dimensions, volume fraction of particles, internals and radial positions on the heat transfer coefficients is considered in the developed correlations. In addition, the effect of the function forms on the accuracy of calculated local heat transfer coefficients is investigated. The Levenberg-Marquardt Algorithm is used to determine the values of the parameters in the empirical correlations. The recommended correlations can be applied in accurately predicting the heat transfer coefficients in bubble columns.