Column Dimensions Research Articles

Hydraulic Calculations of a Telescopic Water Intake

Abstract Telescopic water intake structures allow for the selective intake of water from the top layers of a reservoir. A telescopic water intake has a high degree of mobility, and a wide field of application; at the same time, it is very simple and convenient to operate. Despite these advantages, an exact calculation method for a telescopic water intake is lacking (Lipin, 2020; Lipin, 2022). Therefore, the purpose of this research is to develop an exact calculation method for a telescopic water intake. In order to perform this task, all the structural elements of a telescopic water intake were analyzed separately by means of existing hydraulic principles. The impact of the critical submergence depth of the water intake funnel on the operability of a telescopic water intake was studied, and an equation for the critical submergence depth calculation was proposed. The optimal range of the flow rate coefficient ( μ =0.30 - 0.45) was proposed for calculating the funnel flow rate, and the correlation between the flow rate and funnel inlet diameter was defined. The optimal curvature radius of the elbow was proposed. In order to verify the above mentioned parameters and correlations, analytical and numerical calculations of specific examples were performed. The results of the numerical modelling demonstrated that the critical submergence depth and shape of the water intake funnel, as defined by the analytical calculations, ensured its effective operation free of cavitation and vortexes. The analytically calculated dimensions of the telescopic column, following the numerical modelling results, provided normal hydraulic conditions without active cavitation. According to the numerical modelling, the proposed curvature radius of the elbow was sufficient to avoid significant cavitation and vortex formation in the elbow structure. This research can provide guidance for the design of telescopic water intake structures.

Disain Kebutuhan Tulangan Glass Fiber Reinforced Polymer (GFRP) Untuk Elemen Struktur Pada Bangunan Beton Bertulang

Fiber Reinforced Polymer is a combination of two main materials Resin Polymer (plastic) as a binder matrix and Fiber (fiber) as reinforcement. This material has three fibers, namely Carbon, Glass, and Aramid. Glass fiber was used in this study, because it has a greater strain compared to other fibers. This study aims to design reinforced concrete structures using steel reinforcement and GFRP as well as to compare the reinforcement requirements of each reinforced concrete. Calculation of reinforcement for steel reinforced concrete refers to SNI 1726-2019, while for GFRP reinforced concrete it is based on ACI 440 1R-2015. This research begins by collecting data in the form of a design structure drawing of a 6-storey hypothetical building, with a total building height of 23 m. The hypothesis building has the number of spans in the X-axis direction is 5 with a distance between columns of 6 m, while the number of spans in the Y direction is 3 with a distance between columns of 5 m. The column dimensions for all floors are 60 cm x 60 cm, while the beam dimensions are 40 cm x 40 cm. The thickness of the floor and roof slabs is 12 cm and the concrete quality is 30 MPa. For the calculation of structural loading, dead load, live load and earthquake load are used and the design of reinforcement for conventional steel reinforced concrete structures and GFRP is carried out. Steel reinforced concrete structures with GFRP reinforced concrete have differences in the amount and diameter of reinforcement required. For beam elements bearing steel reinforcement, 24 pieces of flexural reinforcement are needed with a diameter of 19 mm, while for beam elements, GFRP reinforcement requires 12 pieces of flexural reinforcement with a diameter of 1 inch to 1,128 inches. For the field area, steel reinforcement beam elements need 12 pieces with a diameter of 19 mm, while for GFRP reinforcing beam elements require 8 pieces of flexural reinforcement with a diameter of 0.875 inch to 1.128 inch. In column elements, steel reinforcement and GFRP reinforcement require the same amount of main reinforcement, which is 32 pieces. However, in terms of diameter, steel reinforcement requires 25 mm diameter reinforcement, while GFRP is 1 inch in diameter.

Second-Dimension Temperature Programming System for Comprehensive Two-Dimensional Gas Chromatography. Part 1: Precise Temperature Control Based on Column Electrical Resistance.

A second-dimension temperature programming system (2DTPS) for comprehensive two-dimensional gas chromatography (GC × GC) is introduced, and its performance is characterized. In the system, a commercial stainless-steel capillary column was used for the separation, as a heating element, and as a temperature sensor. The second dimension (2D) column was resistively heated and controlled using an Arduino Uno R3 microcontroller. Temperature measurement was accomplished by measuring the overall 2D column's electrical resistance. A diesel sample was used to compare the 2D peak capacity (2nc) and resolution (2Rs), while a perfume sample was used to compare the reproducibility of the system for within-day (n = 5) and day-to-day (n = 5) results. The 2nc improved by 52% with the 2DTPS compared to the secondary oven. The GC × GC system utilizing the 2DTPS had an average within-day and day-to-day relative standard deviation (RSD) of 0.02 and 0.12% for the 1D retention time (1tR), 0.56 and 0.58% for the 2D retention time (2tR), and 1.18 and 1.53% for the peak area, respectively.

Stability indicating HPLC method development and validation of Fostemsavir in bulk and marketed formulations by implementing QbD approach

Background: Achieving a predictable degree of quality with intended and planned specifications is known as "quality by design." QbD (Quality-by-Design) is an alternative to conventional method development that places more attention on identifying and mitigating potential risks. Component of the Quality-by-Design methodology involves conducting a series of experiments to learn how various factors, including the dependant variables, affect the answers of interest. Here, we use a QbD (Quality-by-Design) loom to detail the creation and verification of a stability-indicating high-performance liquid chromatography (HPLC) method for Fostemsavir in both bulk and finished-goods forms.
 Results:
 In this work, we present a workable experimental design for optimising the RP-HPLC separation technique by identifying the optimum mobile phase concentration and flow rate. Below are the ideal chromatographic conditions as calculated by Design Expert version 13.0: Mobile phase: 80 parts acetonitrile to 20 parts formic acid (v/v), flow rate: 0.8 millilitres per minute, retention time: 3.24 minutes, column dimensions: GIST C18 (250 mm × 4.6 mm × 5.0 μm).
 Here we propose a practical experimental layout for determining the optimal mobile phase concentration and flow rate for the RP-HPLC separation technique. Using Design Expert version 13.0, the optimum chromatographic conditions were determined to be as follows: Shim-pack GIST C18 (250 mm 4.6 mm, 5.0 μ), mobile phase acetonitrile to 1% formic acid (80:20, v/v), flow rate 0.8 ml/min, and retention period 3.24 min.
 At a detection wavelength of 266 nm, it was discovered that the devised technique was linear over a concentration range of 50-90 μg/ml (r2 = 0.997). Test parameters for the system's appropriateness were determined to be 1.124 for the tailing factor and 9480 for the theoretical plates. Intraday RSD was found to range from 0.70 to 0.94, whereas interday RSD was found to range from 0.55 to 0.95 percent. Values for robustness were under 2%. The solution stability % RSD was calculated to be 0.83. The result of the assay was 100.05 percent. The created methodologies were used to studies of forced degradation, and the stressed materials were analysed. The parameters used to validate the procedure fell within the acceptable range recommended by ICH.
 Conclusion: Using Design Expert 13.0, we created a central composite design experiment that illustrates the relationships between mobile phase and flow rate across three levels, with retention duration, tailing factor, as well as theoretical plates as the responses of interest. By this work, we gain insight into the variables that affect chromatographic separation and strengthen our conviction that the HPLC method we've devised will serve our needs. Quantitative method development was applied to improve comprehension of multi-tiered method variables.

Additional Fire Exposure Time for the Effect of Spalling in Reinforced Concrete Columns

Concrete exposed to fire can experience spalling when the pore pressure increases due to water evaporation resulting in damage to part of the concrete cross-section which causes the loss of the initial cross-sectional symmetry, both thermal and geometrical. This may lead to what is, in essence, a biaxial bending problem in reinforced concrete columns. This study does not deal with the prediction of the occurrence of spalling for which a fully coupled hygro-thermo-mechanical analysis would be required. This work evaluates the consequences that corner spalling and surface spalling have on the fire resistance of reinforced concrete columns and presents a methodology based on the determination of a modified fire resistance time. An advanced fiber based numerical model for evaluating the fire resistance of RC sections exposed to fire is used as a tool to analyse the effect that spalling has on the performance of the columns. The model is able to generate the interaction surfaces of the columns subjected to uniaxial or biaxial bending and 4-sided exposed to the standard fire curve ISO 834. After a parametric analysis, it is observed that the negative effect of spalling can be quantified by means of an additional fire exposure time, which ranges between 0–35 min and depends on the column cross-section configuration, dimensions and load level. Finally, a proposal for the calculation of the modified fire resistance time for the effect of spalling is presented, which may be beneficial for practitioners in design.

Building Analysis of the Lill Hajj Wall Umrah Building Based on Functionality of the Building for Umrah and Hajj Pilgrims

PT Lill Hajj Wall Umrah is targeted to get 5,226 consumers per year or equivalent to 436 people per month by 2030. The old office in the form of a shophouse with a building area of 119.75 m² for a capacity of 99 people is considered inadequate to serve 436 consumers per month, so PT Lill Hajj Wall Umrah needs a new office with a meeting room of at least 523.2 m². A new office will be planned based on SNI 2847-2019, SNI 1726-2019, SNI 1727-2020, and PBI 1983. The planning results are in the form of an analysis of the new office structure with building dimensions of 28.30 x 23.35m, four floors with a building area of 4,503 m². The material specifications of the building structure are concrete quality (fc') 41.5 MPa, melted reinforcing steel quality (fy) 400 MPa (BJTS), and 280 MPa (BJTP). Basement floor column dimensions 0.6 x 0.6 m, first to fourth floor columns 0.5 x 0.6 m, rooftop columns 0.4 x 0.4 m, main beam dimensions 0.25 x 0.35 m, child beams 0.25x0.5 m, stair beams 0.25 x 0.35 m, roof deck beams 0.25 x 0.3 m and 0.3 x 0.4 m, concrete slab thickness 0.15 m. The results of structural modeling using the Etabs application showed that there was no over-strength (O/S) in the column and beam structure elements. The results of the design of the new office building Lill Hajj Wall Umrah in the form of a basement floor equipped with prayer room facilities covering an area of 14 m2, a generator room covering an area of 15.28 m2, a pump room covering an area of 15.28 m2, parking covering an area of 781.53 m2. The first floor is equipped with VIP room facilities covering an area of 33.33 m2, a prayer room covering an area of 25.87 m2, a toilet covering an area of 44.93 m2, and a boutique room covering an area of 55.22 m2, and a warehouse covering an area of 12.3 m2. The second floor is equipped with a meeting room covering an area of 47.9 m2, a manager's room covering an area of 36.7 m2, a toilet covering an area of 30.9 m2, a prayer room covering an area of 16.08 m2, a boardroom covering an area of 80.59 m2 and a waiting room covering an area of 45 m2. The third and fourth floors are equipped with toilets covering an area of 25.75 m2, a prayer room covering an area of 23.95 m2, and a ballroom of 383.75 m2. The estimated budget for the construction of lill Hajj Wall Umrah's new office is Rp 7.612.645.721.- and takes 406 working days for construction.

Tube-in-tube rigid beam to CFT column connection in moment-resisting frames: An experimental study

Using concrete-filled steel tube (CFT) columns in high-rise buildings has attracted considerable attention in recent years. Aside from its advantages, rigid beam to CFT column connections are followed by some challenges. Difficult construction and implementation, sophisticated details of connection, and most importantly, placing and welding internal stiffeners (continuity plates) are among the common challenges. In the present study, a novel connection called “Tube-in-Tube (TIT) connection” has been proposed. In TIT connection, an inner tube and a pair of vertical straps are utilized in the panel zone area. To investigate the proposed connection, two full-scale specimens were tested using cyclic reversal loading. The two specimens were identical in dimensions and detailing, except for their strap width and the diameter of inner tube. Specimen 1 and Specimen 2 were detailed with inner tube diameter equal to half and one-third of the column dimension, respectively. The inter-story drift ratio, joint's shear deformation, plastic hinge formation, and energy dissipation capacity were analyzed. Moreover, mechanical parameters such as yield and ultimate strengths, and ductility of the specimens were calculated. Specimen 2 showed 3% and 8% increase in the peak flexural strength and cumulative energy dissipation in comparison with Specimen 1. The results showed that the panel zone remain elastic during the test. In order to further investigate the proposed connection, finite element (FE) analysis was conducted on the specimen. The results of FE analysis confirmed the elastic behavior of the tube and straps.

EVALUASI PERENCANAAN STRUKTUR ATAS PADA PELAKSANAAN PEMBANGUNAN MASJID JAMI’ MANDIANGINKOTA BUKITTINGGI

The planning for the construction of the Jami' Mandiangin mosque starts from the planning of the lower structure to the upper structure. In the formulation of the problem, the researcher only calculates the maximum load borne by the building, both dead load, live load and earthquake load and to know the dimensions of the structural elements and the amount of structural reinforcement needed. The research methodology is divided into two types, namely quantitative methods and qualitative methods. The study used SAP2000 to analyze the structural design to determine the magnitude of the load carried on the construction of a structural building that refers to SNI 2019. The results of the study obtained the dimensions of a circular column with a diameter of 600 mm, a column height of 4500 mm with a lot of reinforcement 17D19. Beam B1 is 450x900 mm with lots of 20D19 reinforcement. Beam B2 is 300x600 mm with a lot of 12D19 reinforcement. Beam B3 is 250x450 mm with lots of 8D19 reinforcement. The floor slab uses 10 - 200 mm in two layers with a floor slab thickness of 12 mm. From the results of the study, it was concluded that the calculation of the structure plays an important role in the construction of the structure so that it can produce a strong and sturdy building.

Abstract 5380: Systematic evaluation and comparison of drug response prediction models: a case study of prediction generalization across cell lines datasets

Abstract Predictive modeling holds great promise for improving personalized cancer treatment and efficiency of drug development. In recent years, deep learning (DL) has been extensively explored for drug response prediction (DRP), outperforming classical machine learning in prediction generalization to new data. Despite the considerable interest in DRP, no agreed-upon methodology for evaluating and comparing the diverse DL models yet exists. Existing papers generally demonstrate the performance of proposed models using cross-validation within a single cell line dataset and compare with baseline models of their choice, substantially limiting the scope and validity of model evaluation and comparison. In this work, we investigate the ability of DRP models for generalizing predictions across datasets of multiple drug screening studies, a more challenging scenario mimicking practical applications of DRP models. Five cell line datasets and six community DRP models with advanced DL architectures have been explored. Public cell line drug screening datasets have been curated and processed for this analysis, including CCLE, CTRP, GDSC1, GDSC2, and GCSI. For each dataset, the same preprocessing pipeline was used to generate cell line gene expressions, drug representations, and drug response values. The six DRP models include advanced architectures and feature engineering methods such as transformer, graph neural network, and image representation of tabular data. Systematic model curation and training have been applied, including consistent training and testing data splits across models and hyperparameter optimization (HPO). To cope with the large-scale model training and HPO, automatic workflows have been implemented and executed on high-performance computing systems. A 5-by-5 matrix of prediction scores, corresponding to the five datasets in both row and column dimensions, has been generated for each model, with off-diagonal values representing the cross-dataset generalization. Despite the advanced DL techniques, all models exhibit substantially inferior performance in cross-dataset analysis as compared with cross-validation within a single dataset. This result demonstrates the challenge of cross-dataset generalization for DRP and motivates the need for rigorous and systematic evaluation of DRP models, which simulates real-world applications. Citation Format: Alexander Partin, Thomas S. Brettin, Yitan Zhu, Jamie Overbeek, Oleksandr Narykov, Priyanka Vasanthakumari, Austin Clyde, Sara E. Jones, Satishkumar Ranganathan Ganakammal, Justin M. Wozniak, Andreas Wilke, Jamaludin Mohd-Yusof, Michael R. Weil, Alexander T. Pearson, Rick L. Stevens. Systematic evaluation and comparison of drug response prediction models: a case study of prediction generalization across cell lines datasets. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5380.

Critical Study of Behavior of RC Structural Frame with Floating Column

Abstract: The infrastructural boom during last decade as resulted in construction of many high rise structures in all mega cities Due to the existence of architect and structural designer have provided floating column in many location in structure. The building become vulnerable to earthquake hazard due to improper way of flow of earthquake force to ground due to discontinuity in the form of floating column brought into structure floating column provided at some location result in close loop and redistribution of moment and forces may prove to be beneficial in restricting dimension of beam and column it may also help in achieving in desire economy. In this project analysis and design of a G+14 RC building is done by introducing the floating column in different conditions such as internal floating column, external floating column and alternate level floating column for determining parameter like displacement, forces and moments is done by using ETAB software

Seismic behavior of wide-limb special-shaped columns composed of concrete-filled steel tubes

To study the seismic performance of wide-limb L-shaped columns composed of concrete-filled steel tubes (W-LCFST columns), five specimens were fabricated and tested under quasi-static cyclic loading. The W-LCFST column was composed of a center mono column, two side mono columns, and vertical connecting steel plates. The mono column was made of steel tube and an infill of concrete. The cavity between the vertical connecting plates was also filled with concrete. The test focused on the parameters including vertical connecting plates with headed studs or perfobond leiste (PBL) stiffeners inside and the sectional dimension of the side mono column. The ultimate failure mode, force-displacement curves, ductility, strength degradation, stiffness degradation, energy dissipation capacity, and strain distribution under different influence factors were discussed. The results showed that all specimens exhibited buckling and fracture failure at the bottom of the W-LCFST column. Increasing the width of the side mono column can increase the initial stiffness. Compared with the headed studs, the PBL stiffeners had a better effect on preventing large-area buckling of the vertical connecting plates and improving the peak bearing capacity and stiffness. Based on the limit state theory, the calculation method of the sectional flexural capacity of the W-LCFST column was established. Additionally, the accuracy of predicting the compression and bending capacity of the W-LCFST column under positive and negative loads by Standard CECS159–2004 was analyzed, and the recommended correction value was also given.

Development of an On-Line Two-dimensional Normal Phase Liquid Chromatography System for Analysis of Weakly Polar Samples

In this study, a novel on-line two-dimensional (2D) normal phase × normal phase liquid chromatography (NPLC × NPLC) was developed for the separation of weakly polar samples. The 2D NPLC was integrated by a unique designed solvent evaporation (SE) interface, including a 6-port 2-position valve and a 10-port 2-position valve in conjunction with two silica gel-packed enrichment columns. The enrichment columns played a pivotal role in evaporating normal phase (NP) solvent from the first dimensional NPLC under vacuum and elevated temperature condition. The working parameters of the interface were evaluated comprehensively. To demonstrate the resolving powerful 2D system, we analyzed three natural-sourced weakly polar compounds from the extracts of toad venom, dammar resin, and propolis. To this end, we studied the effects of mobile phase combinations, the second dimensional column length for separation of the extracts from toad venom, and propolis, respectively. In general, we have found that excellent separation can be obtained with diversity of NP solvent combinations and longer NPLC column (150 mm long). Moreover, compared with the generally used 2D reversed-phase liquid chromatography (RPLC × RPLC), the NPLC × NPLC method exhibited better separation orthogonality. In conclusion, the new NPLC × NPLC separation method provides potential advantages for analysis of weakly polar samples.

Punching Capacity of UHPC Post Tensioned Flat Slabs with and Without Shear Reinforcement: An Experimental Study

Punching capacity is one of the main items in the design of both pre-stressed and non-pre-stressed flat slabs. All international design codes include provisions to prevent this type of failure. Unfortunately, there is no code provision for UHPC yet, and hence, the aim of this research is to experimentally investigate the impact of column dimensions and punching reinforcement on the punching capacity of post-tensioned slabs and compare the results with the international design codes’ provisions to evaluate its validity. The test program included five slabs with a compressive strength of 120 MPa: one as a control sample, two to study the effect of column size, and the last two to study the effect of punching reinforcement. Comparing the results with the design codes showed that ACI-318 is more accurate with an average deviation of about 5%, while EC2 is more conservative with an average deviation of about 20%. Besides that, punching reinforcement reduces the size of the punching wedge by increasing the crack angle to 28° instead of 22° for slabs without punching reinforcement. Also, the results assure that both ductility and stiffness are enhanced with the increased column dimensions and punching reinforcement ratio. Doi: 10.28991/CEJ-2023-09-03-06 Full Text: PDF

Rebar Replacement in Severely Damaged RC Bridge Column Plastic Hinges: Design Criteria and Experimental Investigation

This paper presents a procedure for rehabilitating plastic hinges with damaged/fractured weldable longitudinal rebars in severely damaged reinforced concrete (RC) bridge columns and possible improvements regarding connection protection and plastic hinge development. Damaged/fractured longitudinal rebars are replaced with new rebar segments, and the basis of this approach involves connecting intermediate machined parts to the original longitudinal rebars by welding with an off-the-shelf steel equal angle. The proposed rehabilitation design procedure is based on capacity design principles, with equations that define the new geometries and required ductility, and it is validated experimentally on three 1∶6-scale RC circular column specimens. Compared with the original columns, the ductility capacity of the rehabilitated columns increased from 39% to 58%, and the energy dissipation (equivalent viscous damping ratio) increased from approximately 50% to 250%. The base shears of the rehabilitated columns were smaller than those of the original columns owing to the reduction in the rebar area; thus, shear failure was avoided, and the demand on the foundation was reduced. The rehabilitation procedure, by adopting a welding connection that is easily performed on site and concentrates the damage in the new rebar segments, promises to be a quick, simple, reliable, and effective means to improve the ductility and shear capacity of RC bridge columns without using mechanical couplers or changing the column dimensions.

Hedychium spicatum rhizome essential oil induces apoptosis in human prostate adenocarcinoma PC-3 cells via mitochondrial stress and caspase activation

Hedychium spicatum is an essential oil bearing plant extensively used in the traditional system of medicine in several countries. Previous research has revealed H. spicatum essential oil (HSEO) to exhibit anti-tumor activity, although the mechanism of action is still unknown. Therefore, the current study was designed to carry out a comprehensive characterization of HSEO and evaluate the chemotherapeutic potential of HSEO against cancerous cells. The volatile constituents of HSEO was determined by one-dimensional gas chromatography with time-of-flight mass spectrometry (GC-TOFMS) and two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS). In total, 193 phytocompounds could be detected, out of which 140 were identified for the first time. The major phytoconstituents detected by GCxGC-TOFMS were β-pinene (10.94%), eucalyptol (6.45%), sabinene (5.48%) and trans-isolimonene (5.00%). GCxGC-TOFMS analysis showed two and half fold increase in the constituents over GC-TOFMS due to better chromatographic separation of constituents in the 2nd dimensional column. HSEO was tested for in vitro cytotoxic activity against cancerous (PC-3, HCT-116 and A-549) and normal (3T3-L1) cell, with HSEO being most selective for prostate cancer cell (PC-3) over non-tumorigenic fibroblast (3T3-L1) cell. HSEO treatment inhibited the colony formation ability of PC-3 cells. HSEO treatment caused apoptotic cell death and cell cycle arrest at G2/M and S phase in PC-3 cells. HSEO induced apoptosis via intracellular ROS accumulation, mitochondria depolarization and increased caspase-3, 8, and 9 levels in PC-3 cells. Additionally, HSEO treatment led to a decrease of Bcl-2 and Bcl-xL and increase of Bax and Bak protein levels. Overall, results from this study highlighted the anticancer potential of H. spicatum essential oil, which could be considered as a new agent for treating prostate cancer.

Behavior of RC columns incorporating with steel and recycled plastic fibers under eccentric load: An experimental work

AbstractThere was a dearth of research into the behavior of eccentric RC columns reinforced with fibers, particularly recycled plastic fiber (RF) reinforced columns. The effect of employing end hooked steel fiber (EF) and RF on the performance of eccentric columns was explored in this experiment. Under compressive eccentric load, eight RC columns of 150 × 150 × 1000 mm with a 2% longitudinal reinforcement ratio were tested up to failure. The ratio of load eccentricity to column dimension was 15%. The fiber content (Vf) was variable. Both EF and RF had a Vf of 1%, 2%, and 3%. The applied load was recorded axial/lateral displacement and transverse/longitudinal reinforcement strain. The ultimate load (Pu), ultimate displacement, yield load, stiffness, and ductility index (∆) were all calculated to investigate column behavior. Results showed that adding fibers prevented the concrete cover separation hence prevented the sudden failure as it happened in the control column without fiber (P0). 1% RF and 2% EF enhanced Pu by 10.4% and 34.8%, respectively, while fiber content 3% decreased Pu. Stiffness of columns containing 1% RF and 2% EF was 16.3% and 33.8% higher than that of P0, respectively. The use of 1% and 2% EF delayed yield load, resulting in improved column performance. All fiber contents significantly improved ductility, with enhancement rates ranging from 4.2% with 3% RF to 146.2% with 3% EF. Also, use of 1% RF increased ductility by 70.6%.

Roll motion mitigation of a barge-type floating wind turbine under random excitation using a tuned liquid column damper

ABSTRACT This paper aims to numerically evaluate the performance of tuned liquid column damper (TLCD) on mitigating roll motion of a barge-type floating wind turbine system subjected to random excitation. The governing equations for modeling the interaction between the roll motion of the floating system and liquid sloshing in the TLCD were derived using a Lagrangian approach. Random excitation based on wave spectrum was generated to simulate applied moment. Then, under the constraints of barge dimension and vertical liquid column movement, Den Hartog’s method was used to obtain optimum TLCD parameters. The results show that the optimally designed TLCD can efficiently mitigate the roll motion of the floating wind turbine.

A detailed evaluation of the advantages and limitations of online RP-LC×HILIC compared to HILIC×RP-LC for phenolic analysis

The combination of hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RP-LC) has proved effective in the LC × LC analysis of polyphenols due to the high degree of orthogonality associated with these separation modes for various classes of phenolic compounds. However, despite the growing number of such applications, HILIC is almost exclusively used as the first dimension (1D) separation mode, and RP-LC in the second dimension (2D). This is somewhat surprising in light of the potential advantages of swapping these separation modes. In this contribution, we present a detailed evaluation of the potential of online RP-LC × HILIC-MS for the analysis of phenolic compounds, comparing the performance of this system to the more established HILIC × RP-LC-MS configuration.Method development was performed using a predictive optimisation program, and fixed solvent modulation was employed to combat the solvent incompatibility between HILIC and RP-LC mobile phases. Red wine, rooibos tea, Protea and chestnut phenolic extracts containing a large diversity of phenolic compound classes were analysed by both HILIC × RP-LC- and RP-LC × HILIC-MS in order to compare the separation performance.Overall, the kinetic performance of HILIC × RP-LC was found to be clearly superior, with higher peak capacities and better resolution obtained for the majority of samples compared to RP-LC × HILIC analyses using similar column dimensions. Dilution of the 1D solvent combined with large volume injections proved insufficient to focus especially phenolic acids in the 2D HILIC separation, which resulted in severe 2D peak distortion for these compounds, and negatively impacted on method performance. On the other hand, a noteworthy improvement in the sensitivity of RP-LC × HILIC-MS analyses was observed due to higher ESI-MS response for the 2D HILIC mobile phase and greater sample loading capacity of the 1D RP-LC column, brought on by the high solubility of phenolic samples in aqueous solutions. As a result, a significantly higher number of compounds were detected in the RP-LC × HILIC-MS separations. These findings point to the potential advantage of RP-LC × HILIC as a complementary configuration to HILIC × RP-LC for phenolic analysis.

Segmented two-dimensional liquid chromatography. Proof of concept study

The separation in liquid chromatography is defined either by the space domain where it proceeds until the least retained analyte reaches the outlet of the column or by the time when individual analytes elute out of the column. These two approaches lead to the four possible combinations of two-dimensional liquid chromatography with online space x time coupling being the least experimentally feasible. Here, we show the development of a novel two-dimensional liquid chromatography method combining separation defined by space and the conventional elution-based separation. First-dimension column consisted of four capillary segments coupled serially via two-position six-port valves allowing an online and comprehensive transfer of analytes from the first to the second dimension. After initial experiments using homemade monolithic capillary columns, we tested commercially available columns in both dimensions. We ended with the combination of packed capillary columns in the first dimension and monolithic capillary column in the second dimension. We used a reversed-phase retention mechanism in the first spatial dimension, while HILIC was in the second, time-based dimension. We also developed a theoretical model to describe the proposed two-dimensional separation that was further confirmed by utilizing both an isocratic and gradient elution in the second dimension. Finally, we applied our experimental setup to separate neurotransmitters contained in human urine.

Analysis of axial and rotational restrained concrete-filled steel tube columns at elevated temperature

This paper has two aims, first, to develop a simplified finite element (FE) model to simulate and study the behaviour of restrained concrete-filled steel tube (CFST) columns subjected to axial force and fire, and second, to propose simplified design equations. FE model has been developed using the ABAQUS program and verified against published data. Furthermore, a parametric study has been conducted using the verified FE model to study different parameters that might affect the behaviour of restrained concrete-filled steel tube columns subjected to axial force under elevated temperatures. These parameters are load level, section type (circular and square), axial and/or rotational restraint ratio, type of steel tube (carbon and stainless steel), type of concrete (carbonate and siliceous concrete aggregate), steel yielding strength, concrete compressive strength, column dimension, width to thickness ratio and reinforcement ratio. Finally, simplified design equations are proposed to determine the buckling time, critical time and maximum load capacity of axial and rotational restrained CFST columns under fire.