Opening Diameter Research Articles

Mechanical performance of hybrid high-strength steel composite cellular beam under low cyclic loading

This study aimed to compensate for the impairments in structural load-carrying capacity and stiffness caused by conventional reduced web section beams, and to meet the strength design requirements for engineering. A new hybrid high-strength steel composite cellular beam (HHS-CCB) using high-strength steel in the beam flange and ordinary steel in the web was proposed. A composite cellular beam between the rigid joint and inflection point in the frame structure was selected as the research object, and low cyclic loading tests were conducted on one homogeneous ordinary steel composite cellular beam (HOS-CCB) and four HHS-CCB specimens. The effects of the hybrid use of high-strength steel and ordinary steel on the failure modes, load-carrying capacities, strength and stiffness degradation, ductility, and energy-dissipation capacities of the composite cellular beams were investigated. The test results show that with reasonable values for the diameter of the web opening and for the distance from the first opening at the beam end to the column surface (abbreviated as the hole edge distance), the HHS-CCB specimens exhibit local plastic damage at the first opening at the end of the beam but maintain a good ductility, stiffness degradation, strength degradation, and energy dissipation capacity, while significantly improving the structural load-carrying capacity loss owing to the web opening. Compared with HHS-CCB specimens using HHS in both the upper and lower flanges, the HHS-CCB specimens using HHS only in the lower flange show superior mechanical properties. Considering the poor plastic deformation capacity of HSS, the steel plate strength of the flange should not be much higher than that of the web to ensure the full development of plasticity in the cross-section, and Q460 steel or Q550 steel is generally recommended. A nonlinear finite element (FE) model was developed using ABAQUS software to predict the hysteresis behavior of specimens. Numerical simulation shows that the simplified FE model can be used to simulate the hysteresis performance of HOS-CCB and HHS-CCB.

Numerical investigation of collapse behavior of steel–concrete composite frames containing corrugated webs with and without openings

As an alternative to flat webs (FWs), corrugated webs (CWs) in composite beams have been employed extensively in steel construction systems. However, the collapse behavior of steel–concrete composite frames containing CW beams has not yet been studied and requires urgent investigation. In this study, numerical models were developed to explore the collapse behavior of these composite frames in an internal column removal scenario. Subsequently, the verified modeling methods were used to conduct a comparative study on the collapse resistance performance of models containing FW and CW beams with and without openings to explore the evolution of their collapse behavior. The results reveal that the load-resisting mechanisms of the composite frames containing FW and CW beams are substantially different. The total resistance of the composite frames containing FW beams is a result of both flexural and catenary action, whereas that of the frames containing CW beams is mainly a result of flexural action only. Appropriate openings on the beam web can intensify the catenary action. Furthermore, an extensive numerical parametric study of the composite frames containing CW beams was conducted to elucidate the effect of key parameters, such as the corrugate shape, type, and angle, on the collapse behavior. The effects of the opening type, diameter, end distance, and spacing on the collapse behavior of these frames is also investigated. Finally, three strategies for improving the bearing capacity of the composite frames containing CW beams with openings are proposed: reinforcement by stub tubes, kinked plates, and a skin diaphragm. The results reveal that all these strategies can substantially improve the bearing capacity.

The magnitude of stress concentration of I-beam with web opening because of lateral-torsional buckling effects

PurposeIt is generally known that the perforated section such as the castellated section is good to sustain distributed loads but inadequate to sustain highly concentrated loads. Therefore, it is possible to design the opening in a different arrangement of web opening to achieve section efficiency, thus improving the strength and torsional behaviour of the section with web opening. This study aims to focus on the finite element analysis of I-beam with and without openings in steel section dominated to lateral-torsional buckling behaviour.Design/methodology/approachIn this work, the analysis of different sizes, shapes and arrangements of web opening is performed by using LUSAS application to conduct numerical analysis on lateral-torsional buckling behaviour. This involves three diameter sizes of web opening, five types of opening shapes and two criteria of the model.FindingsThe section with c-hexagon web opening was placed about 200-mm centre to centre and 100-mm edge distance, contribute to 7.26% increase of buckling capacity. For the section with 150-mm centre to centre and 50-mm edge distance, the occurrence of local buckling contributes to decrease of lateral buckling section capacity to 19.943 kNm, where pure lateral-torsional buckling mostly occurred because of prevented section. Besides that, the web opening diameter was also analysed. The web crippling was observed because of the increase of opening diameter from 0.67 to 0.80 D.Originality/valueThis contributes to a decrease in buckling capacity as figured in the contour of the deformed shape. For Model 1, an increase of buckling capacity (31.46%) is observed when the opening diameter are changed from 0.67 to 0.80 D.

A new sand raining technique to reconstitute large sand specimens

Abstract Sand raining is among the popular techniques used in the laboratory for preparing sand samples. Factors like the deposition intensity (DI) and the falling height (HF) affect the produced relative density (RD) in this technique. Studies showed that the RD increase as the HF increases. This is, however, applicable up to a critical HF beyond which the RD seems unaffected. According to previous experiments, the maximum RD achieved using the sand raining is about (70 ± 5)%. The preparation of samples with higher RD is a prerequisite required in many experimental models. In the present article, a new raining system, which is capable to prepare sand samples with a very high RD and with a fast sand flow, is introduced. The new system was used to examine the relationship between the HF and the RD under different trapped air pressures and using rain nozzles with three different opening diameters. The new system was found appropriate for reconstituting SP-SM with very dense specimens (RD > 99%) with achieving higher DI values and a reduction in preparation time of more than 90% in comparison to the classic raining technique. It is time-saving and very suitable to reconstitute large model soil specimens effectively and quickly.

Multifunctional Amine Modifiers for Selective Dehydration of Methyl Lactate to Acrylates.

Dehydration of methyl lactate to acrylic acid and methyl acrylate was experimentally evaluated over a Na-FAU zeolite catalyst impregnated with multifunctional diamines. 1,2-Bis(4-pyridyl)ethane (12BPE) and 4,4'-trimethylenedipyridine (44TMDP), at a nominal loading of 40 wt % or two molecules per Na-FAU supercage, afforded a dehydration selectivity of 96 ± 3% over 2000 min time on stream. Although 12BPE and 44TMDP have van der Waals diameters approximately 90% of the Na-FAU window opening diameter, both flexible diamines interact with internal active sites of Na-FAU as characterized by infrared spectroscopy. During continuous reaction at 300 °C, the amine loadings in Na-FAU remained constant for 12BPE but decreased as much as 83% for 44TMDP. Tuning the weighted hourly space velocity (WHSV) from 0.9 to 0.2 h-1 afforded a yield as high as 92% at a selectivity of 96% with 44TMDP impregnated Na-FAU, resulting in the highest yield reported to date.

A Model for the Determination of Semi-Circular Spot Corrosion Damage and Residual Strength in Oil Pipes

Pitting corrosion often occurs due to the presence of various corrosive substances, such as CO2 and H2S, in the pipe service environment. As a result of this process, the residual strength of oil pipes is reduced and this can compromise the integrity of the entire pipe string. In the present work, a model is introduced on the basis of the API579 standard to determine the so-called stress concentration coefficient. The model accounts for pitting corrosion shapes such as shallow semi-circles, semi-circles, and deep semi-circles. The relationship between the corrosion pit depth and opening diameter and the residual strength of the oil casing is obtained. The results show that the influence of the pit opening diameter on the stress concentration coefficient is smaller than that of the pit depth. For a constant pit opening diameter, the coefficient increases gradually with increasing the pit depth. The compressive strength and internal pressure strength of the carbon steel oil casing decrease accordingly. When the depth of the corrosion pit is relatively small, the growth of the coefficient is slower; when the depth of the corrosion pit increases to a certain value, the increase in stress concentration coefficient becomes obvious.

Formation of volatile liquid jets in a rarefied medium

The external signs and conditions for the occurrence of sudden changes in the direction of ethanol micro-jets during vertical, from top to bottom, outflow from small-diameter capillaries into a rarefied medium (vacuum) are considered. A brief description of the equipment used, the organization of liquid preparation for the experiment, and the control of parameters are given. With the help of photo and video equipment, sudden transitions from dark areas of the jet to light ones and vice versa, stratification of the liquid jet into two, three or more fan streams, i.e. bifurcation. It is shown that with a decrease in the diameter of the capillary opening, the jet outflow is more stable, and the flow can retain its shape for a relatively long period of time. The process established by other researchers of the flow of liquid drops up the capillary has been confirmed. The reliability of the obtained results was verified by comparison with the known data by organizing the outflow from the same capillaries into the atmosphere.

Effects of intraocular lens anterior edge design on anterior capsule morphology changes following femtosecond laser-assisted capsulotomy

PurposeTo compare morphological changes in the anterior capsule of two intraocular lenses (IOLs) with different anterior edge designs 6 months after femtosecond laser-assisted capsulotomy surgery (FLACs).MethodsThis study included 168 eyes from168 patients undergoing FLACs. Group A included 74 eyes from 74 patients who had an Acrysof IQ Restor SN6AD3 IOL implantation with a flat anterior edge and Group B included 94 eyes of 94 patients with a TECNIS Multifocal ZMB00 IOL implantation and a "peak-like" anterior edge. All patients were followed up for 6 months. We assessed anterior capsule morphological changes including variation of anterior opening diameters and lens epithelial cell (LEC) proliferation in four directions, variation of anterior opening area, and the level of anterior capsule opacification (ACO).ResultsVariation of anterior opening diameters in 4 directions were significantly lower in Group B (P < 0.05). Obvious shrinkage ratio of anterior opening diameters and contraction of anterior opening area (P < 0.05) appeared in Group A. LEC proliferation was along the "peak" in Group B, while it spread to the edge of anterior capsule in Group A. ACO grades 6 months after operation in Groups A and B were as follows: grade I in 28.38% and 82.98% of eyes, grade II in 51.35% and 17.02% of eyes, and grade III in 20.27% and 0% of eyes, respectively.ConclusionsThese findings suggest that a "peak-like" IOL anterior edge design played an important role in maintaining the morphology of anterior capsule in the early postoperative stage.

Characters Association and Path Coefficient Analysis among Quantitative Traits of Chrysanthemum (Dendranthema×Grandiflora Tzvelev)

The present experiment was carried out under naturally ventilated polyhouse at the experimental farm of Division of Flower and Medicinal Crops, ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka, India for two years during 2019 (August-November) and 2020 (August-December) The experiment was laid out in completely randomized design (CRD) with three replications under naturally ventilated polyhouse. Analysis of variance showed significant differences among genotypes for all the traits. Results revealed that the days to optimum flowering exhibited positive and significant correlation with plant height (0.599), days to bud initiation (0.628), days to first flower opening (0.985) and flowering duration (0.571), whereas, positive significant correlation with flower diameter (0.324). The results of path coefficient analysis using correlation coefficients revealed that days to first flower opening (1.033) exhibited positive and very high direct effect on days to optimum flowering while, number of leavesplant-1 (0.040), days to bud initiation (0.056), flower diameter (0.025) and flower duration (0.022) showed positive and negligible direct effect. Therefore, the selection on the basis of traits viz., plant height, days to bud initiation, days to first flower opening, flower duration and flower diameter will be more effective for improvement of the flowering traits in chrysanthemum breeding.

Control Efficiency of Biochar Loaded with Bacillus subtilis Tpb55 against Tobacco Black Shank

Black shank caused by Phytophthora nicotianae has become a destructive soil-borne disease to different flue-cured tobacco cultivars in Southwest China. The use of biochar amendments for microorganism synergy is a promising effective strategy for P. nicotianae development control. In this study, biochar samples were prepared from tamarisk with different pyrolization temperatures (300–500 °C). The effect of pyrolytic temperatures on the bacteria immobilization efficiency of biochar was investigated. B. subtilis Tpb55 was successfully loaded on different biochars as biocontrol composites. The survival investigation of the inoculum suggested that biochar pyrolized at 300 °C (BC300), with a large pore opening diameter; a greater pore volume exhibited a better Tpb55 immobilization. A pot experiment indicated that Tpb55-loaded BC300 had a more pronounced decrease in the disease severity index of black shank disease and an increase in the soil pH, alkali-hydrolyzable nitrogen, soil-available phosphorus, and available potassium. BC300 inoculated with Tpb55 showed the highest control effect (79.60%) against tobacco black shank in the pot experiments, with the lowest copy number of P. nicotianae DNA. In conclusion, biochar-immobilized Tpb55 may provide a new strategy for preventing and controlling tobacco black shank.

Investigations on the compressive behaviour of novel cell size graded primitive lattice structure produced by Metal Additive Manufacturing

In this research work, a novel cell size graded sheet primitive type Triply Periodic Minimal Surface (TPMS) lattice structure is designed and built using Selective Laser Melting (SLM) of SS316L powder. Manufacturability and compressive behaviour are analyzed and compared with the uniform Primitive structures. The pore opening diameter was measured using Scanning Electron Microscopy (SEM). The graded structure revealed a higher quasi-elastic modulus than the uniform structures, while the Energy Absorption characteristics are almost the same in all of them. The graded structure exhibited a distinct order of crushing among the layers. Overall, such structures are found to be worthy candidates for load-bearing parts with considerable energy absorption in biomedical applications.

Finite element analysis and structural optimization of V-shaped seal ring based on ANSYS Workbench

Based on the finite element analysis software of ANSYS Workbench, the sealing performance of a V-shaped seal ring is analyzed. It is found that the position of the maximum shear stress of the V-shaped seal ring is on both sides of the bottom of the opening. Then, the effects of root height h and opening arc diameter D on the maximum shear stress and maximum contact pressure of the seal ring are studied, and the parameters are optimized accordingly. Further, the ultimate working pressure of the optimized structure is analyzed. The results show that the maximum shear stress and maximum contact pressure of the seal ring increase with the root height, but there is a downward inflection point at h-0.2. The maximum shear stress of the seal ring increases with the opening arc diameter, but there is a rising inflection point at D-0.2. Further, the maximum contact pressure of the seal ring first increases rapidly and then increases slowly with the opening diameter. The working oil pressure that the V-shaped seal ring can bear is 1.3 MPa. The simulation results can guide the design of the V-shaped seal ring.

Gating with Charge Inversion to Control Ionic Transport in Nanopores.

Multivalent ions modify the properties of the solid/liquid interfaces, and in some cases, they can even invert the polarity of surface charge, having large consequences for separation processes based on charge. The so-called charge inversion is observed as a switch from negative surface charge in monovalent salts, e.g., KCl, to effective positive surface charge in multivalent salts that is possible through a strong accumulation and correlation of the multivalent ions at the surface. It is not known yet, however, whether the density of the positive charge induced by charge inversion depends on the pore opening diameter, especially in extreme nanoconfinement. Here, we probe how the effective surface charge induced by charge inversion is influenced by the pore opening diameter using a series of nanopores with an opening between 4 and 25 nm placed in contact with trivalent chromium ions in tris(ethylenediamine)chromium(III) sulfate at different concentrations. Our results suggest that the effective positive charge density can indeed be modified by nanoconfinement to the extent that is dependent on the pore diameter, salt concentration, and applied voltage. In addition, the correlated ions can increase the transmembrane current in nanopores with an opening diameter down to 10 nm and cause a significant blockage of the current for narrower pores. The results provide guidelines to control ionic transport at the nanoscale with multivalent ions and demonstrate that in the same experimental conditions, differently sized pores in the same porous material can feature different surface charge density and possibly ion selectivity.

Elastic buckling of simply supported stiffened steel plates with circular opening

Steel plates are used as the main components of steel elements in many structures. Openings in steel elements may exist for maintenance or inspection purposes in addition to creating paths for different fixtures such as air conditioning, pipes, and facilities. The structural performance of plates with openings is different from that of solid plates when subjected to axial compressive load. Openings affect local buckling, lateral torsional buckling, and shear of plates. Adding stiffeners around openings is a common engineering practice to strengthen plates. However, different design codes and guides provide estimates of the flexural and shear capacity of beams with no clear formulas for the influence of such openings on axial buckling strength. In this study, a parametric study has been performed using general-purpose finite element software, ANSYS, in order to study the effect of using stiffeners around circular opening in simply supported axially loaded plates on the elastic buckling behavior. Different parameters were considered including the aspect ratio of the plate, opening diameter, opening position in both horizontal and vertical directions, and stiffener’s dimensions. The results of the extensive parametric study are used to propose an empirical design formula considering the different studied parameters.

The CathPilot: A Novel Approach for Accurate Interventional Device Steering and Tracking

Accurate device navigation and control are significant challenges in various minimally invasive cardiovascular interventions. The long length of the devices used (e.g., catheters and guidewires), their high flexibility, and their engagement with the tortuous anatomy limit the accurate and reliable control and navigation of the device's tip. This article aims to design, develop, and assess a novel alternative solution that promises to overcome the major limitations of conventional devices. By utilizing an expandable cable-driven mechanism and a corresponding 3-D cam surface for cable length adjustment, we propose a fully manually operated system that can be navigated through the tortuous anatomy and then teleoperated to allow for accurate, reliable, and localized position control and tracking of the device. In this article, the methods of design, development, and verifications of this system are presented. The system's performance is assessed under different path tortuosity conditions and different opening diameters of the expandable frame. Our results indicate that the proposed system provides complete teleoperation of the device within the full reachable workspace of the mechanism and allows for positioning and tracking of the device with submillimeter accuracy irrespective of the tortuosity of the path and expansion size of the frame. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ex-vivo</i> phantom model experiments also show the device significantly outperforms conventional devices in terms of navigation time and success rate. The CathPilot allows for direct manipulation, accurate positioning, and tracking of the device tip relative to the anatomy, promising to overcome some of the major limitations of conventional interventional devices.

Similarity solution of subcritical pressure discharges from vessels for arbitrary gases

Based on the Bernoulli’s equation Fischer and Boettcher (2021) developed a model to predict the transient gas discharge from a vessel. Their dimensionless number was able to capture a variation of the molar mass, temperature, vessel volume and opening diameter and showed constant values for these. The influence of the gas, though, could not be completely captured. In this work we improve the model by optimizing the pressure loss coefficient, modifying the dimensionless number and solving the differential equation for determining the pressure over time using the 4th-order Runge-Kutta method. The model was extended to include the influence of the ambient pressure. These improvements lead to the first similarity correlation valid for arbitrary gases. Multiple numerical simulations are performed with ANSYS CFX to verify the similarity model. A grid independence study showed differences below 1 %. The mean deviation between the numerical simulation and the similarity-model is 1.939 %.

Study on anti-progressive collapse performance of cellular steel frames with different web opening shapes

In this paper, cellular beam-column joints with different opening shapes were taken as the object of study to investigate the resistance to progressive collapse of weakened beam-column joints through a combination of experiments and numerical simulations. Opening shapes include circular, rectangular and hexagonal. The development laws of failure mode, vertical force–deformation response, internal force development and resistance mechanism of the specimens were analyzed, and based on the validated finite element model, the effects of weakening parameters of openings with different opening shapes on the performance of the beam-column joints against progressive collapse were studied. The results demonstrate that the load carrying capacity and deformation capacity of cellular joints with different opening shapes have different degrees of improvement compared with the foundation joints, and exhibit the largest deformation in the first opening area near the column flange, where the ductile failure at the weakened section occurs in the hexagonal cellular opening, and the catenary effect can be fully developed, showing the best performance under the designed opening size, rectangular is the second and circular the worst. In addition, the failure mode and load carrying capacity of the specimens can be effectively improved by changing the opening weakening parameters. Increasing the opening diameter (parameter a) and opening edge distance (parameter c) within a reasonable range can effectively improve the vertical resistance and deformability of the specimens, and the effect of opening spacing (parameter b) on the structural load response is negligible. In the design of collapse resistance of cellular beam-column joints, it is recommended to increase the values of parameters a and c appropriately and to reduce the value of parameter b appropriately under the premise of ensuring the structural load carrying capacity, which is more conducive to the catenary action.

Assessment by finite element modeling of corrosion in dent on X52 steel pipelines

While corrosion in dent presents a realistic threat to integrity of pipelines, there have been limited methods available to assess the problem and its effect on fitness-for-service of the pipelines. In this work, a method was developed to assess the corrosion in dent on an X52 steel pipe by considering both mechanical and electrochemical corrosion factors and their interaction at an unconstrained dent through finite element modeling. Parametric effects including dent depth, dent size (i.e., open mouth diameter for spherical dents) and internal pressure on distributions of stress, anodic current density and net current density were determined. The stress concentration at the dent accelerates corrosion due to a mechano-electrochemical interaction. As the dent depth increases, the local stress concentration is enhanced, resulting in increased corrosion activity and corrosion rate. The most negative corrosion potential and the maximum anodic current are located at the center of the dent, where the anodic reaction occurs. The cathodic reaction mainly occurs at the dent sides. The internal pressure has a limited effect on the anodic current density. The dent with a smaller open diameter can cause greater local stress concentration and anodic current density. At specific dent depths, small dents tend to accelerate local corrosion at a more rapid speed than bigger dents.

The Relationship between Burrow Opening Dimensions and Biomass of Intertidal Macroinvertebrates by Feeding Mode (Surface Deposit Feeders vs. Suspension Feeders).

Simple SummaryTo specially quantify the biomass of intertidal macroinvertebrates, a fundamental metric in the fields of ecology, has long remained a challenge, especially for cryptic species. This study classified intertidal macroinvertebrates by feeding mode, such as surface deposit feeders and suspension feeders, and tested whether the biomass can be estimated from their burrow opening dimension. These results indicated that the burrow opening dimension of the surface deposit feeder was available as a proxy for biomass. However, we cannot yet generalize about direct relationships between the opening dimension and biomass for suspension feeders due to a relatively low correlation between them.Biomass and abundance are fundamental parameters in ecology, conservation biology, and environmental impact assessment. Distinguishing features, such as burrow openings and feeding pellets, made by different intertidal macroinvertebrate species on the surface are used as proxies to establish the abundance of intertidal macroinvertebrates. This study investigated the feasibility of estimating biomass from the burrow opening dimensions as a proxy. We analyzed the relationship between the burrow opening dimensions and body weights of intertidal macroinvertebrates and compared surface deposit feeders with suspension feeders. Regression analysis evaluated the relationship between burrow opening diameter, body size, and biomass. The diameters of surface deposit feeder burrow openings were significantly related to biomass, but this was not the case for suspension feeders. Our results indicate that burrow opening dimensions can be used as a proxy to estimate the biomass of surface deposit feeders. However, additional studies are needed to clarify further the relationship between the burrow opening diameter and biomass of the suspension feeders. This is a preliminary study to spatially quantify the biomass of intertidal macroinvertebrates by extracting the dimension of burrow openings from drone images through object detection tools.

Interpenetrating phase composites with 3D printed triply periodic minimal surface (TPMS) lattice structures

Micro-selective laser melting fabricated triply periodic minimal surface sheet lattice and epoxy interpenetrating phase composites (IPCs) are investigated in this paper. To achieve superior specific energy absorption (SEA) enhancements in the composites, an optimised Schwarz primitive lattice (P-lattice) structure is proposed by redefining the shell opening diameter with a shape parameter. Also, the influences of fabrication directions, along the [100], [110], and [111] lattice directions, on the mechanical responses of the P-lattices and IPCs are presented. Compression results reveal that the modified P-lattices outperform the original P-lattices with superior compressive strength and SEA. The P-lattices also display the lowest strength and SEA along [100] as compared to that of [110] and [111]. The compressive strength and SEA of modified P-lattice along [111] are 123.66% and 64.63% higher than its [100], respectively. As for the IPCs, up to a 52% increase, from the linear addition of the two-component phases has been achieved for SEA. The IPCs also exhibit a superior specific energy absorption of 49.6 J/g, a 1109% improvement from that of the pure lattice, which is attributed to the high strength and large plateau strain of the composites. The simulation results show that the internal energy of both lattice and epoxy in composites is 136% and 21%, respectively, higher than that of single structures due to the interaction effects.