Column Dimensions Research Articles

Experimental Study of the Effects of Silica-gel Bed Thickness on The Regeneration Process in a Desiccant Column

A desiccant column contains a silica gel as a solid moisture absorbent material has been used in this study, in which the regeneration or desorption process was discussed. The dimensions of the silica-gel column are 30 cm long*30 cm wide with three thickness of desiccant bed (5,10, &15) cm, respectively. The mass flow rate and the inlet temperature of the regeneration air used are 3.72 kg/min and 53 °C respectively. This air was obtained using solar air heater in addition to an electric heating unit for temperature control purpose. The results obtained showed that the regeneration period is affected by the bed thickness. Increasing the bed thickness of silica increase the regeneration period and vice versa For example, the complete drying process of silica gel from moisture took 21 min with thickness of bed (5 cm), while it took 42 min with thickness of bed (15 cm)

Reliability assessment of moment resistance frames under earthquake loads

In this study a single bay three storey Moment Resisting frame with bracing and without bracing with different dimensions of columns, Beams have been chosen to perform the study on a Semi -Rigid structure. The frame is analyzed by mode superposition method. For earthquake resistant Structures as proposed by the IS 1983(Part1): 2002 suggest that column must be stronger than beams. A parametric study is made by varying the Moment of inertia of beam section. The ratio of height to width is greater than unity ensuring the frame as Moment resisting frame. The frames are filled with masonry and it is modeled as a braced member for the frame. Two types of frames were studied one with bracing and the other as bare frame. Generalized computer program in MAT LAB has been developed for static loads. An Elcentro earthquake has been scaled and the frames were analyzed one with bracing and other is bare frame. A reliability assessment is performed on the two types of the frames by considering the uncertainties in the Geometry, Strength and loads.

The Structural Planning of Bunda Halimah Hospital Universitas Batam Using Steel Frame Construction

The structural planning of the Bunda Halimah Hospital Universitas Batam uses steel frame construction, planning includes calculating the load acting on the structure, namely in the form of dead loads, living loads, not taking into account earthquake loads. The height of the column in the planning of the Structure of the Bunda Halimah Hospital, is as high as 23.5 m. The process of analyzing the planning of building structures using the ETABS program. Guided by the Indonesian Steel Building Loading Regulations 1984 and SNI steel, to analyze the calculation of the dimensions of columns, beams and plates. The results of the loading calculation based on the Indonesian Steel Building Planning Regulations of 1984 were obtained for this building using WF 250x250x9x14kg/m child beams, WF Main Beams 300x300x10x15kg/m, WF building columns 350x350x12x19 kg/m, and using concrete plates for roofs with a thickness of 100 mm of D8 – 200 mm reinforcement and concrete plates for floors with a thickness of 120 mm of D8 - 200 mm reinforcement.

HBIM LIBRARY DEVELOPMENT FOR A DORIC TEMPLE COLUMN

Abstract. The growing interest within the construction industry in the preservation, rehabilitation, and conservation of heritage-value buildings has led to the implementation of Historic Building Information Modelling (HBIM). Especially in Greece, where the number of historical buildings is considerably large, having efficient and standardized processes of Cultural Heritage management and conservation becomes a prerequisite. The rigorously accurate representation of old constructions requires specific geometric modelling processes in order to generate the necessary relevant libraries of parametric objects. This paper describes the development of a parametrized library for the main parts of a Doric Temple to be used for introducing such parts in an HBIM system. Moreover, to verify the correctness of the parametrized column an application is performed in which the dimensions of a real column are compared with the dimensions of the standard one. The study improves the potential of the BIM process for its application to buildings with distinctive architecture in the context of the preservation or conversion of heritage buildings. In first section the term HBIM is explained and its usefulness to cultural heritage (CH) is justified. Section 2 describes previous attempts to create HBIM libraries for historic structures. After that, the construction of parametric model, which was created with visual programming Dynamo, is presented. Finally, the efficiency of the adjustment of a standard column to a given point cloud is described and in the end the results of the application are compared and discussed.

A simplified coupled model for predicting dynamic processes of vehicle impact on pier columns

Vehicle collision upon pier columns has become a very severe threat to the structural safety and normal operation of highway bridges. Substantial scientific investigations were therefore conducted over the past several decades to understand the mechanical phenomenon involved in vehicle-pier collision events through experimental and finite-element (FE) numerical approaches. Whilst both approaches require a substantial investment of time and effort, the equivalent static approach that is easy for computation has been adopted by many design specifications. However, the static method ignores important dynamic effects such as inertia effects, which may lead to inaccurate prediction results. Therefore, the development of numerically accurate and computationally efficient simplified impact models using macro-level elements to replicate the complex FE models of vehicles and impacted structures has drawn the attention of many researchers. In this paper, a simplified mass-spring model using three non-linear springs working in parallel is proposed to replicate a realistic truck model, and a set of regression formulas are developed to calculate the spring parameters which are correlated to pre-specified design parameters including truck weight, impact velocity, and cross-section dimension of a pier column. By coupling the mass-spring model to a pier column which is discretized into a series of lumped masses and fiber beam elements, a coupled model is developed to predict the time-histories of impact forces and dynamic structural responses during impact. Benchmark numerical data generated by detailed FE simulations are employed to calibrate the proposed coupled model, which is shown to be able to provide very reliable predictions of the dynamic processes for different impact scenarios.

A STABILITY INDICATING RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR THE SIMULTANEOUS ESTIMATION OF DAUNORUBICIN AND CYTARABINE IN BULK AND PHARMACEUTICAL DOSAGE FORM

Objective: A simple, accurate, and precise method was developed for the simultaneous estimation of daunorubicin and cytarabine dosage form using reverse-phase HPLC and validated with different parameters such as accuracy, precision, repeatability, linearity, limit of detection (LOD), and limit of quantitation (LOQ) as per ICH Q2R1 guidelines. Methods: The chromatogram was run through Agilent C18 Column of dimensions 150×4.6 mm, 5 m. Mobile phase containing 0.01N KH2PO4: Methanol taken in the ratio 50:50 was pumped through the column at a flow rate of 1.0 ml/min. The temperature was maintained at 30°C. The optimized wavelength selected was 240 nm. Results: Retention times for daunorubicin and cytarabine were found to be 2.433 min and 3.045 min. The %RSD of the daunorubicin and cytarabine was found to be 0.7 and 0.4, respectively. The %Recovery was obtained as 99.96% and 100.40% for daunorubicin and cytarabine, respectively. LOD and LOQ values obtained from regression equations of daunorubicin and cytarabine were 0.08 μg/ml, 0.24 μg/ml and 0.94 μg/ml, 2.86 μg/ml, respectively. The regression equation for daunorubicin is y=28587x+3141 and y=35995x+37534 for cytarabine. Conclusion: The method developed was simple and economical that can be adopted in regular quality control tests in industries.

Experimental and numerical investigations on moment redistribution in reinforced concrete frames subjected to vertical loads

In this study, experimental and numerical investigations of the moment redistribution behaviour in reinforced concrete (RC) frames subjected to vertical monotonic loads are presented. By testing 12 RC single-storey continuous frames over two equal spans of 3000 mm, the evolution of moment redistribution during the whole process of loading was observed, and two-stage moment redistribution that occurred at the serviceability limit state (SLS) and ultimate limit state (ULS) was proposed. The test results showed that with the increase in the yield strength of the reinforcement, the degree of moment redistribution at SLS was improved, which should not be neglected in the prediction of the permissible moment redistribution. Meanwhile, the strain penetration of the high-strength reinforcement was more obvious. This is beneficial to the moment redistribution in frame beams. To further investigate the influence of various parameters on the two-stage moment redistribution quantitatively, a nonlinear finite element (FE) model based on the damage plasticity constitutive law was developed and verified using the teste results. A parametric study was conducted based on 96 simulated specimens and the influential factors included the neutral axis depth factor, yielding strength of reinforcement, concrete strength, geometric dimensions of the frame columns and beams, M-V interaction, and loading patterns. The results indicated that M-V interaction had a detrimental effect on the plastic moment capacity, thus promoting the process of moment redistribution in RC structures. Based on the experimental and FE results, new practical calculation formulas that comprehensively reflected the influential factors were proposed to estimate degree of two-stage moment redistribution in RC frames.

Punching Shear Strength of FRP-Reinforced Concrete Slabs without Shear Reinforcements: A Reliability Assessment.

The recent failure of buildings because of punching shear has alerted researchers to assess the reliability of the punching shear design models. However, most of the current research studies focus on model uncertainty compared to experimentally measured strength, while very limited studies consider the variability of the basic variables included in the model and the experimental measurements. This paper discusses the reliability of FRP-reinforced concrete slabs’ existing punching shear models. First, more than 180 specimens were gathered. Second, available design codes and simplified models were selected and used in the calculation. Third, several reliability methods were conducted; therefore, three methods were implemented, including the mean-value first-order second moment (MVFOSM) method, the first-order second moment (FOSM) method, and the second-order reliability method (SORM). A comparison between the three methods showed that the reliability index calculated using the FOSM is quite similar to that using SORM. However, FOSM is simpler than SORM. Finally, the reliability and sensitivity of the existing strength models were assessed. At the same design point, the reliability index varied significantly. For example, the most reliable was the JSCE, with a reliability index value of 4.78, while the Elgendy-a was the least reliable, with a reliability index of 1.03. The model accuracy is the most significant parameter compared to other parameters, where the sensitivity factor varied between 67% and 80%. On the other hand, the column dimension and flexure reinforcement are the least significant parameters compared to other parameters where the sensitivity factor was 0.4% and 0.3%, respectively.

Intensification of Heat and Mass Transfer in a Diabatic Column with Vortex Trays

We used vortex contact devices that we developed and investigated to make a new design of an alcohol diabatic distillation column with heat exchange pipes (as the reflux condenser) passing through concentrating section trays. In the column, ascending vapors partially condensed on the surface of vertically installed heat exchange tubes, forming a reflux. The reflux was then mixed with the draining liquid flow in the vortex contact devices placed on the trays. Heat was removed from the column through the boiling of the draining water film along the inner surface of the heat exchange pipes. We compared both diabatic and adiabatic columns fitted with the developed vortex contact devices on the trays. The proposed innovative contact system allows increasing productivity, reducing column dimensions and steam- and heat-transfer medium consumption, and increasing separation efficiency. Dependences for calculating the gas content, hydraulic resistance, and interphase surface required for designing the vortex contact devices of the proposed unit trays are presented.

Using Artificial Intelligence Techniques to Predict Punching Shear Capacity of Lightweight Concrete Slabs.

Although lightweight concrete is implemented in many mega projects to reduce the cost and improve the project’s economic aspect, research studies focus on investigating conventional normal-weight concrete. In addition, the punching shear failure of concrete slabs is dangerous and calls for precise and consistent prediction models. Thus, this current study investigates the prediction of the punching shear strength of lightweight concrete slabs. First, an extensive experimental database for lightweight concrete slabs tested under punching shear loading is gathered. Then, effective parameters are determined by applying the principles of statistical methods, namely, concrete density, columns dimensions, slab effective depth, concrete strength, flexure reinforcement ratio, and steel yield stress. Next, the manuscript presented three artificial intelligence models, which are genetic programming (GP), artificial neural network (ANN) and evolutionary polynomial regression (EPR). In addition, it provided guidance for future design code development, where the importance of each variable on the strength was identified. Moreover, it provided an expression showing the complicated inter-relation between affective variables. The novelty lies in developing three proposed models for the punching capacity of lightweight concrete slabs using three different (AI) techniques capable of accurately predicting the strength compared to the experimental database

Simultaneous evaluation of the enantiomeric and carbon isotopic ratios of Cannabis sativa L. essential oils by multidimensional gas chromatography.

Recent times have witnessed an upsurge of interest in hemp and hemp-derived products, as driven by the scientific findings specific to the pharmacological properties of Cannabis sativa L. and its constituents. There has been evidence that the terpene profile, along with the cannabinoid content, produces in humans the effects associated with different strains, beyond fragrance perception. A great deal of effort has been put into developing analytical approaches to strengthen the scientific knowledge on cannabis essential oil composition and provide effective tools for ascertaining the authenticity of commercial cannabis samples. For this concern, enantio-selective-GC-C-IRMS has proven to be effective for assessing the ranges characteristic of the genuine samples and detecting any fraudulent additions. This research aimed at providing for the first time the enantiomeric and isotopic ratios of target terpenes in cannabis essential oils, obtained from microwave-assisted hydro-distillation from the fresh and dried inflorescences of different cannabis varieties. Implementing multidimensional gas chromatography separation was mandatory prior to detection, in order to obtain accurate δ13C values and enantiomeric data from completely separated peaks. For this purpose, a heart-cut method was developed, based on the coupling of an apolar first dimension column to a secondary chiral cyclodextrin-based stationary phase. Afterwards, the data gathered from enantio-selective-MDGC-C-IRMS/qMS analysis of a set of genuine samples were used to evaluate the quality of nineteen commercial cannabis essential oils purchased from local stores. Remarkably, the data in some cases evidenced enantiomeric ratios and δ13C values outside the typical ranges of genuine oils. Such findings suggest the usefulness of the method developed to ascertain the genuineness and quality of cannabis essential oils.

An AI-based Lagrange optimization for a design for concrete columns encasing H-shaped steel sections under a biaxial bending

ABSTRACT shaped steel sections subjected to biaxial loads. The Lagrange multiplier method is used to optimize cost index (CIc), and CO2 emission of the columns. ANNs can be implemented to generalize functions for objective parameters CIc , and CO2 emission. Generalized functions can replace complex analytical functions that are difficult to derive when optimizing objective functions. In the AI-based Lagrange multiplier method, dimensions of columns and steel sections are calculated as output parameters corresponding to minimized CIc , and CO2 emission. Note that 3D interaction diagrams of SRC columns subjected to biaxial bending and concentric axial loads are also formulated based on optimal results. An accuracy of the ANN-based optimal designs is demonstrated using structural mechanics based on a strain compatibility. A hybrid network based on both ANNs and Lagrange multiplier method identified design parameters which reduced CIc , and CO2 emission of a column by 30.7% and 40.4% respectively, when compared with those of a conventionally designed column.

Structural design of the radar station of “Besna Kobila” Serbia

Abstract The location of the new radar station facility is located at the top of the Besna Kobila mountain in Serbia at an altitude of approximately 1904 m. The construction of the building is reinforced concrete. The building consists of ground floor and first floor with technical and other areas. From the 2nd to the 6th floor there is a communication central reinforced concrete core. At the level of the 6th floor, a platform was formed for storing equipment and supporting the antenna dome with a diameter of R = 15. The total height of the building with a dome is H = 37.0 m. Horizontal floor structures are in the form of reinforced concrete slabs supported on reinforced concrete walls 20 (30) cm thick, columns of different dimensions, and a system of reinforced concrete beams of different cross section. The vertical construction consists of load-bearing reinforced concrete columns, external and internal concrete walls. In the central part of the building, there is a staircase in the form of reinforced concrete slabs with a thickness of d = 16 cm, as well as reinforced concrete elevator core with a square base of approximately 560.0 cm. The calculation of the structure is performed for loads from its own weight, constant loads from the materialization of the object, loads from the equipment and for payloads: from snow and wind and seismic loads of intensity IX. The basic load of the dome is the wind according to the average speed of 70.0 m / sec (according to the measured data). The foundation of the building is on a reinforced concrete slab and reinforcements-capitals under the columns.

A new hybrid lattice-Boltzmann method for thermal flow simulations in low-Mach number approximation

A new low-Mach algorithm for the thermal lattice Boltzmann method (LBM) is proposed aiming at reducing the computational cost of thermal flow simulations in the low Mach number limit. The well-known low Mach number approximation is adopted to accelerate the simulations by enlarging the time step through re-scaling the psuedoacoustic speed to the same order of the fluid motion velocity. This specific process is inspired by the similarity between the artificial compressibility method and the isothermal LBM and is further extended to its thermal counterpart. It must be emphasized that such low-Mach acceleration strategy is in a general form, thus can be easily applied to other compressible LB methods. The present method overcomes the drawback of the classical pressure gradient scaling method due to the pressure gradient changing. The new algorithm is validated by various well-documented academic test cases in laminar [one dimensional gravity column, 2D (two dimensional) rising thermal bubble, and 2D differentially heated square cavity] and turbulent [3D (three dimensional) Taylor–Green vortex and 3D heated cylinder] regimes. All the results show excellent agreement with the reference data and high computational efficiency.

Analysis of simplified time of liquefaction triggering methods by laboratory tests, physical modelling and numerical analysis

The damage resulting from earthquakes can result from the combination of seismic excitation and/or due to a build-up of excess pore pressure in the soil (liquefaction). These two effects are related since the reduction of soil stiffness due to a decrease in effective stress, modifies the seismic response of the soil deposit. Therefore, the expected level and type of damage is dependent on the amount of seismic energy reaching the ground surface before liquefaction. The development and validation of simplified liquefaction assessment methods to provide reasonable estimates of the build-up of excess pore pressure is essential for improving estimates of the level of seismic demand (ground shaking and permanent ground deformation) that may be experienced by a building. This paper presents two methods, one based on equivalent cyclic stress loading, and another based on the cumulative strain energy, which are used to predict the evolution of the pore pressure build up throughout time. The centrifuge tests performed in ISMGEO (Italy) during the LIQUEFACT project (www.liquefact.eu) were used as a benchmark to evaluate the predictive performance of the methods. Additionally, a series of one dimensional soil column effective stress and total stress analyses and single soil element simulations were run. Available laboratory tests were used to calibrate the parameters of the simplified methods, as well as input parameters for the numerical simulations. The results showed that both simplified methods had considerable bias. A direct comparison of the effective stress analyses, a set of effective stress analyses with limited drainage, and the centrifuge results, highlighted that the centrifuge experiments exhibited significant pore water flow that was not captured in the simplified models. Comparisons between the irregular loading in the one dimensional analyses compared to the uniform loading in the element tests highlighted shortfalls in the conversion from irregular to equivalent uniform loading. Comparisons between stress demands from total stress, effective stress and the simplified methods illustrated the limitations of relying on the total stress acceleration to estimate demands on a soil in a liquefying deposit.

Landfill gas emission through compacted clay considering effects of crack pathway and intensity

Compacted clay barrier plays an important role in reducing landfill gas transport due to its low gas permeability. There is limited understanding of desiccation cracks and to what extent they can cause preferential pathways of landfill gas through compacted clay barriers. This study investigated the intensity and pathway of desiccation cracks as well as its effects on gas emission through compacted clay. The compacted clay with and without scratched compaction interface was subjected to drying to simulate desiccation cracks. The clay was then extruded from large containers into one dimensional columns to allow observation of crack propagation using an X-ray computerized tomography scanner. After that, gas emission rate was measured from each column under different gas pressures (i.e., 1, 5, 10 and 20 kPa). Furthermore, a simplified method is proposed to predict gas emission rate with consideration of intensity and characteristics of cracks. Test results demonstrated that desiccation cracks were initiated mainly at the center of each container (i.e., within 40% of container dimension). Gas emission rate can be increased at least 10 times with the presence of desiccation cracks (i.e., at gas pressure of 5 kPa). As compared to the depth and continuous pathway of cracks which significantly increased gas emission rate, the discontinuous crack pathway can reduce the gas emission rate by up to 3 times. The findings towards crack characteristics and gas emission observed in this study are crucial for safety design and long-term operation of compacted clay barriers in landfill covers.

Analisis Perhitungan Struktur Laboratorium Teknik Sipil Type II Fakultas Teknik Universitas Muhammadiyah (UMSU) Medan

The lack of supporting infrastructure facilities such as the Laboratory at Samudra University, especially in the Civil Engineering Study Program, Faculty of Engineering, has resulted in Samudra University having to work hard in building infrastructure to keep pace with advances in technology and science. This study aims to plan the dimensions and reinforcement of beams, columns, plates and stairs in the Civil Engineering Laboratory building. The laboratory building to be analyzed has a total of 3 floors with floor dimensions of 43 m x 27.49 m. Modeling and analysis of the structure of this building is assisted by the SAP2000 program using the Special Moment Bearing Frame System (SPRMK) and is designed according to SNI 03-1726-2012, SNI 03-2847-2013, and PPPURG 1987. The structure is planned to use concrete quality fc' 30 MPa and steel grade fy 400 MPa. The results of the analysis obtained that the floor slab thickness was 13 cm using D10-200 mm reinforcement for main reinforcement and D10-300 mm for split reinforcement. The thickness of the roof slab is 12 cm using D10-200 mm reinforcement for main reinforcement and D10-300 mm for split reinforcement. The dimensions of the B1 beam are 50 cm x 70 cm using 12D25 for the support area with D10-80 mm braces and 8D25 reinforcement for the field area with D10-120 mm braces. Begel B2 30 cm x 50 cm using 4D25 reinforcement for the support area and field with braces for D10-200 mm field and braces for D10-100 mm support. The dimensions of the K1 column are 60 cm x 80 cm using 10D25 reinforcement with D10-300 mm begel. The dimensions of the K2 column are 60 cm x 60 cm using 8D25 reinforcement with D10 -200 mm begel. The thickness of the ladder plate and landing was obtained 13 cm using D10-200 mm reinforcement.

Behavior of CFST Column to Concrete-Filled U-Shaped Steel Beam Joints with Slabs under Cyclic Loading

This study proposes a through-beam composite joint system to connect square concrete-filled steel tubular (CFST) columns and concrete-filled U-shaped steel (CFUS) beams. In the joint system, channel-shaped holes in the square steel tube allow direct load transfer of the beam. Two procedures for constructing the joints, denoting two types of joint details (i.e., Type-I and Type-II), are proposed to facilitate field installation. Six cruciform joints were tested under combined constant axial compression and cyclic lateral loading. Three Type-I joints were tested. The main test parameters were the loading procedure and the axial load ratio applied on the CFST column. All Type-I specimens reached their beam flexural capacities followed by the fracture of fillet welds at beam ends, as well as the fracture of the reduced steel section within the joint zone. Three Type-II joints were constructed with the same column and beam section dimensions as the Type-I specimens. The main test parameters were the additional flexural rebars at beam ends and the axial load ratio. All Type-II specimens reached their beam flexural capacities, followed by the fracture of the heat-affected zone at beam ends. All specimens failed in a ductile manner, had favorable hysteretic performance, and complied with the acceptance criteria. Design considerations are proposed based on the test and analysis results.

BIDIMENSIONAL LINKED MATRIX FACTORIZATION FOR PAN-OMICS PAN-CANCER ANALYSIS.

Several modern applications require the integration of multiple large data matrices that have shared rows and/or columns. For example, cancer studies that integrate multiple omics platforms across multiple types of cancer, pan-omics pan-cancer analysis, have extended our knowledge of molecular heterogeneity beyond what was observed in single tumor and single platform studies. However, these studies have been limited by available statistical methodology. We propose a flexible approach to the simultaneous factorization and decomposition of variation across such bidimensionally linked matrices, BIDIFAC+. BIDIFAC+ decomposes variation into a series of low-rank components that may be shared across any number of row sets (e.g., omics platforms) or column sets (e.g., cancer types). This builds on a growing literature for the factorization and decomposition of linked matrices which has primarily focused on multiple matrices that are linked in one dimension (rows or columns) only. Our objective function extends nuclear norm penalization, is motivated by random matrix theory, gives a unique decomposition under relatively mild conditions, and can be shown to give the mode of a Bayesian posterior distribution. We apply BIDIFAC+ to pan-omics pan-cancer data from TCGA, identifying shared and specific modes of variability across four different omics platforms and 29 different cancer types.

Model-Based Simultaneous Solvent Screening and Column Design Based on a Holistic Consideration of Extraction and Solvent Recovery.

A methodology for a model-based simultaneous solvent screening and dimensioning of extraction columns is presented. Therefore, a rate-based extraction model is combined with a distillation model for solvent recovery and product purification to consider the whole extraction process. The optimal operating point and the required column dimensions are determined for each solvent candidate specifically to minimize total costs, which are used as a basis for solvent ranking. The methodology is applied to the extraction of levulinic acid from an aqueous feed with a special focus on the influence of mutual solubility between the solvent candidates and water. It is shown that using mixture properties for both phases in accordance with the mutual solubility significantly impacts the calculation of fluid dynamics, mass transfer, and thereby on the required extraction column height. Furthermore, additional costs due to solvents solubilized in the aqueous raffinate strongly affect the economic evaluation of the solvents.