Bar Size Research Articles

Heterochrony and parallel evolution of echinoderm, hemichordate and cephalochordate internal bars.

Deuterostomes comprise three phyla with radically different body plans. Phylogenetic bracketing of the living deuterostome clades suggests the latest common ancestor of echinoderms, hemichordates and chordates was a bilaterally symmetrical worm with pharyngeal openings, with these characters lost in echinoderms. Early fossil echinoderms with pharyngeal openings have been described, but their interpretation is highly controversial. Here, we critically evaluate the evidence for pharyngeal structures (gill bars) in the extinct stylophoran echinoderms Lagynocystis pyramidalis and Jaekelocarpus oklahomensis using virtual models based on high-resolution X-ray tomography scans of three-dimensionally preserved fossil specimens. Multivariate analyses of the size, spacing and arrangement of the internal bars in these fossils indicate they are substantially more similar to gill bars in modern enteropneust hemichordates and cephalochordates than to other internal bar-like structures in fossil blastozoan echinoderms. The close similarity between the internal bars of the stylophorans L. pyramidalis and J. oklahomensis and the gill bars of extant chordates and hemichordates is strong evidence for their homology. Differences between these internal bars and bar-like elements of the respiratory systems in blastozoans suggest these structures might have arisen through parallel evolution across deuterostomes, perhaps underpinned by a common developmental genetic mechanism.

Tribocatalysis of homogeneous material with multi-size granular distribution for degradation of organic pollutants

Recently, tribocatalysis driven by mechanical energy has been developed by rubbing two kinds of different materials. In this work, we firstly demonstrated that the friction of the single material also could initiate the tribocatalysis for degrading organic dyes. Under magnetic stirring, the multi-size granular polytetrafluoroethylene (PTFE) particles were triboelectrically charged, among which the collision between large and small particles would cause high energy electrons on large particles to transfer to small ones. These triboelectric charges on PTFE particles could react with adsorbed oxygen molecules or water to generate reactive oxygen species, and then promoted the degradation process of organic dyes together with oxidant holes. We further investigated the experimental parameters, such as stirring speed, size and quantity of stirring bar, to optimize the tribocatalytic performance. What’s more, the PTFE tribocatalysis possessed high durability for multiple recycling runs with > 90% degradation efficiency of Rhodamine B, as well as well universality for eliminating other pollutants. Finally, we proposed a plausible tribocatalytic mechanism of multi-size granular PTFE according to the detected reactive oxygen species and the determined intermediates. This study provides new insights into tribocatalysis, and demonstrates that the single material with different particle sizes can also be used as catalyst to drive tribocatalytic process.

Composition of curvilinearly extendable tubular scissor mechanisms

Scissor mechanisms are used as deployable structures in industrial products, architecture, and aerospace structures. In general, tubular scissor mechanisms (TSMs), composed of scissor-like elements on their surrounding facets, extend collinearly to serve as lifters, masts, and bridges. Furthermore, curved TSMs can form circular arches to serve as spatial frames and space antennas. However, previous studies proposed limited configurations of TSM models and did not present detailed geometrical formulations. This paper presents new compositions of curved TSMs that can extend by winding two-dimensionally or twisting three-dimensionally. Detailed geometrical formulations of the scissor-like elements were analytically derived to generate a variety of extended shapes. In addition to the numerical simulations using 3D CAD, physical models were assembled to verify their deployability considering realistic sizes of bars and joints. This work widens the deployability of extendable scissors mechanisms, which will eventually broaden the usage of this structure in practical applications.

Initial experiments to assess short-term survival of discarded plaice (Pleuronectes platessa) caught in trammel nets during winter season

European plaice (Pleuronectes platessa) is a key species in commercial fisheries in the North Sea, Skagerrak, Kattegat, and Baltic Sea. The reformed European Union Common Fisheries Policy includes the possibility of exemptions from the landing obligation for “species for which scientific evidence demonstrates high survival rates”. Discard survival from set-net fisheries is poorly studied. Trials were conducted on two commercial fishing vessels over seven trips from November to February 2017–2018 in the Baltic Sea. The nylon trammel nets had a nominal bar size for the inner/outer wall of 75/350 mm and 85/400 mm. Soaking time was 23–47 h, water depth 7–18 m, and deck temperature was −0.1–6.0 °C. Following commercial practice, the trammel nets were hauled back onto the vessel, after which netting and fish passed through a net hauler onto a steel sorting table where the entire fish catch were manually untangled by the fishers and plaice collected by scientists. We used a storage system for housing the captured fish inside fishing harbours during observations. Catch-damage-index (CDI) and Reflex Action Mortality Predictor (RAMP) scores were used to assess fish condition immediately after capture and at the end of observation periods. All plaice below 40 cm were sampled with a total number of 118 individuals from 13 fleets (several nets joined together). The fish were assessed for short-term survival for 4–10 days with full survival (100%). The majority of fish exhibited no reflex impairments. Minor bruises, fraying, and net marks were frequently observed on captured fish. The overall condition of the fish did not change during observation periods.

Fatigue life of C-FRCM strengthened corroded RC continuous beams under multi-intervention system

A new fatigue life prediction model for reinforced concrete (RC) beams is proposed. The model was applied to carbon-fabric reinforced cementitious matrix (C-FRCM) strengthened corroded RC beams under the impressed current cathodic protection (ICCP) and structural strengthening (SS) multi-intervention system. The stress development of steel bar in the fatigue process was captured by employing the fracture mechanics and finite element (FE) analysis. The concept of equivalent initial flaw size (EIFS) was also introduced to account for the actual initial micro crack size of steel bar. The feasibility of the model was validated through comparisons of the numerical deflection, the strain of steel bar and fatigue life of RC beams against the test results. The validated model was then used to examine the effects of key parameters including load level, corrosion degree of steel bar and polarization degree of C-FRCM. Furthermore, the results of the parametric study were used to fit S-N curve and analyse the reliability. The high accuracy of the model was shown to be suitable for the fatigue life prediction of ICCP-SS system in long-term service. It was also found that the fatigue life of the corroded RC beams was greatly improved through strengthening with C-FRCM.

The evolution of the barred galaxy population in the TNG50 simulation

ABSTRACT We use the magnetic-hydrodynamical simulation TNG50 to study the evolution of barred massive disc galaxies. Massive spiral galaxies are already present as early as z = 4, and bar formation takes place already at those early times. The bars grow longer and stronger as the host galaxies evolve, with the bar sizes increasing at a pace similar to that of the disc scalelengths. The bar fraction mildly evolves with redshift for galaxies with $M_{*}\ge 10^{10}\rm M_{\odot }$, being greater than $\sim 40{{\ \rm per\ cent}}$ at 0.5 < z < 3 and $\sim 30{{\ \rm per\ cent}}$ at z = 0. When bars larger than a given physical size ($\ge 2\, \rm kpc$) or the angular resolution limit of twice the I-band angular PSF FWHM of the HST are considered, the bar fraction dramatically decreases with increasing redshift, reconciling the theoretical predictions with observational data. We find that barred galaxies have an older stellar population, lower gas fractions, and star formation rates than unbarred galaxies. In most cases, the discs of barred galaxies assembled earlier and faster than the discs of unbarred galaxies. We also find that barred galaxies are typical in haloes with larger concentrations and smaller spin parameters than unbarred galaxies. Furthermore, the inner regions of barred galaxies are more baryon-dominated than those of unbarred galaxies but have comparable global stellar mass fractions. Our findings suggest that the bar population could be used as a potential tracer of the buildup of disc galaxies and their host haloes. With this paper, we release a catalogue of barred galaxies in TNG50 at six redshifts between z = 4 and 0.

Prediction of residual tensile strength of glass fiber reinforced polymer bars in harsh alkaline concrete environment using fuzzy metaheuristic models

The long-term durability of glass fiber reinforced polymer (GFRP) bars in harsh alkaline environments is of great importance in engineering, which is reflected by the environmental reduction factor in various structural codes. The calculation of this factor requires robust models to predict the residual tensile strength of GFRP bars. Therefore, three robust metaheuristic algorithms, namely particle swarm optimization (PSO), genetic algorithm (GA), and support vector machine (SVM), were deployed in this study for achieving the best hyperparameters in the adaptive neuro-fuzzy inference system (ANFIS) in order to obtain more accurate prediction model. Various optimized models were developed to predict the tensile strength retention (TSR) of degraded GFRP rebars in typical alkaline environments (e.g., seawater sea sand concrete (SWSSC) environment in this study). The study also proposed more reliable model to predict the TSR of GFRP bars exposed to alkaline environmental conditions under accelerating laboratory aging. A total number of 715 experimental laboratory samples were collected in a form of extensive database to be trained. K-fold cross-validation was used to assess the reliability of the developed models by dividing the dataset into five equal folds. In order to analyze the efficiency of the metaheuristic algorithms, multiple statistical tests were performed. It was concluded that the ANFIS-SVM-based model is robust and accurate in predicting the TSR of conditioned GFRP bars. In the meantime, the ANFIS-PSO model also yielded reasonable results concerning the prediction of the tensile strength of GFRP bars in alkaline concrete environment. The sensitivity analysis revealed GFRP bar size, volume fraction of fibers, and pH of solution were the most influential parameters of TSR.

Horizontal target size perturbations during grasping movements are described by subsequent size perception and saccade amplitude.

Perception and action are essential in our day-to-day interactions with the environment. Despite the dual-stream theory of action and perception, it is now accepted that action and perception processes interact with each other. However, little is known about the impact of unpredicted changes of target size during grasping actions on perception. We assessed whether size perception and saccade amplitude were affected before and after grasping a target that changed its horizontal size during the action execution under the presence or absence of tactile feedback. We have tested twenty-one participants in 4 blocks of 30 trials. Blocks were divided into two experimental tactile feedback paradigms: tactile and non-tactile. Trials consisted of 3 sequential phases: pre-grasping size perception, grasping, and post-grasping size perception. During pre- and post-phases, participants executed a saccade towards a horizontal bar and performed a manual size estimation of the bar size. During grasping phase, participants were asked to execute a saccade towards the bar and to make a grasping action towards the screen. While grasping, 3 horizontal size perturbation conditions were applied: non-perturbation, shortening, and lengthening. 30% of the trials presented perturbation, meaning a symmetrically shortened or lengthened by 33% of the original size. Participants’ hand and eye positions were assessed by a motion capture system and a mobile eye-tracker, respectively. After grasping, in both tactile and non-tactile feedback paradigms, size estimation was significantly reduced in lengthening (p = 0.002) and non-perturbation (p<0.001), whereas shortening did not induce significant adjustments (p = 0.86). After grasping, saccade amplitude became significantly longer in shortening (p<0.001) and significantly shorter in lengthening (p<0.001). Non-perturbation condition did not display adjustments (p = 0.95). Tactile feedback did not generate changes in the collected perceptual responses, but horizontal size perturbations did so, suggesting that all relevant target information used in the movement can be extracted from the post-action target perception.

The recent rise of craft chocolate in Japan: A 2019 snapshot

Japan is one of the largest consumer markets for chocolate in Asia, which includes the growing craft chocolate industry. However, there is limited literature on craft chocolate in Japan and the craft chocolate industry as a whole. The recent popularity of craft chocolate in Japan implores an investigation of this emerging market. Through an analysis of industry literature, interviews, and craft chocolate makers databases, this research presents an updated (2019) snapshot of the Japanese craft chocolate industry. Early craft chocolate businesses were generally established around 2014, and there are currently about 100 self-identified craft chocolate makers in Japan today. Japanese craft chocolate consumers are interested in craftmanship, novel flavor profiles, unique experiences and packaging, quality, food safety, and health attributes when purchasing craft chocolate products. The most common origins for Japanese craft chocolate (tablet type) bars are geographically diverse, including Vietnam, Peru, and Madagascar. The average size of a craft chocolate bar in Japan is 42.5 g and the average cost is 1216 JPY, almost 10 times higher cost per gram than mass market chocolate bars. Over 78% of Japanese craft chocolate businesses specialize primarily in craft chocolate bar production. Additionally, the online presence and online purchasing options for Japanese craft chocolate brands are limited mostly to Japanese-literate customers through specialty shops, and some brands use exclusively social media platforms for an online presence.

Predicting tensile strength of spliced and non-spliced steel bars using machine learning- and regression-based methods

Mechanical properties of steel reinforcement bars, which have a critical effect in the overall performance of reinforced concrete (RC) structures, should be reported and assessed before being used in structural elements. Determining bars’ properties could be time-consuming and expensive specifically in the case of incorporating splices. Therefore, this study aims to predict tensile strength of bars using machine learning-based methods including nonlinear regression, ridge regression and artificial neural network. To this end, a comprehensive database including over 200 tests on non-spliced and spliced steel bars by mechanical couplers was collected from the available peer-reviewed international publications. Bar size, splice method, steel grade, temperature and splice characteristics (length and outer diameter of couplers) were the input parameters considered for predicting tensile strength. The efficiency of the models was evaluated through Taylor diagram and common performance metrics namely coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE) and mean absolute percentage error (MAPE). The results demonstrated that the predicted values agreed well with the actual values reported in the experimental studies used for collecting the database. A parametric study was also conducted in order to examine the influence of coupler length, coupler outer diameter and temperature on the tensile strength of spliced bars. Based on the parametric study results, three different equations were suggested for calculating tensile strength of spliced bars using the mentioned parameters. The outcomes of this study can assist practitioners to effectively and accurately estimate tensile strength of spliced and non-spliced steel bars in reinforced concrete structures without the need to carry out expensive and timely physical tests.

Influence of ceramic-coating techniques on composite-zirconia bonding: Strain energy release rate evaluation

ObjectivesTo compare ceramic-coating techniques versus conventional techniques on bonding between composite cements and zirconia by means of strain energy release rate (Gc, J/m2). MethodsTwo sizes of zirconia bars (30 mm × 8 mm × 1.5 mm and 14.8 mm × 8 mm × 1.5 mm) were fabricated. Two smaller bars were treated and cemented to the surface of a large bar using one of the following methods: (i) AlN-nano-structured alumina coating with RelyX Unicem 2; (ii) HOT-DCM hotbond coating with G-Multi Primer and G-Cem Linkforce; (iii) LiDi-lithium disilicate glass-ceramic coating with Monobond N Primer and Multilink Speed; (iv) COJ-tribochemical silica treatment with RelyX Ceramic Primer and RelyX Unicem 2; (v) GCEM-alumina grit blasting with G-Multi Primer and G-Cem LinkForce; (vi) MUL-alumina grit blasting with Multilink Speed; and (vii) PAN-alumina grit blasting with Clearfil Ceramic Primer and Panavia F2.0. A total of 30 bilayered specimens in each group were stored in distilled water at 37 °C for 24 h and assigned to three subgroups (n = 10/test group): short-term test, thermocycling for 5000 cycles, and thermocycling for 10,000 cycles and tested in 4-point bending configuration. Results were analysed using two-way ANOVA, followed by one-way ANOVA and Games-Howell (α = 0.05). Failure mode and surfaces were analysed using optical microscopy and SEM. ResultsThe bonding (J/m2) of COJ and MUL groups was significantly higher than the other groups among all aging conditions. Thermocycling affected the bonding in COJ and GCEM groups. SignificanceSurface pre-treatments and artificial aging affect the bonding between composite cements and zirconia.

Size Effect in the Split Hopkinson Pressure Bar Experiment

For many structures, their service environment is very strict, and the requirements for the impact resistance of materials are very high. Therefore, the dynamic testing method has important scientific significance and application value for practical engineering. Split Hopkinson pressure bar (SHPB) is one of the most common experimental methods for obtaining dynamic mechanical properties of materials. However, there is no uniform standard for the size of the bars and specimens used in the test. Theoretically, the size has little influence on the experimental results, but it has not been proved by experiments. This paper mainly studies the influence of device/specimen sizes of split Hopkinson pressure bar through experiments, it is demonstrated that the sizes of bars and specimen have little effect on experimental results.

Study of structural bonding strength with tyre rubber instead of coarse aggregate and water hyacinth ash instead of cement

The report includes an experimental evaluation of concrete bond strength with coarse aggregate partially replaced by reshaped tyre rubber and cement partially replaced by water hyacinth ash. The essential characteristics that were evaluated were reshaped tyre rubber, bar size, embedding length, and water hyacinth ash. The assignment requires two types of mixes: a basic concrete mix and mixes with 0%, 5%, 10%, 15%, and 20% partial substitution of coarse material with reshaped tyre rubber and cement with 10% river hyacinth ash [1]. Two different diameters of High Strength Deformed (HSD) bars (16 mm and 20 mm) are employed with an embedding length of 150 mm. For a total of 28 days, all specimens are submerged in water. The Universal Testing Machine (UTM) is used to calculate the strength and slip values of all PULLING OUT [3] specimens. Bond strength reduces as bar size increases, whereas bond stress is increased as embedding length decreases. Furthermore, coarse aggregate could be partially substituted with reshaped tyre rubber, and cement can be partially replaced with water hyacinth ash [4].

Application of three-dimensional reconstruction technology combined with three-dimensional printing in the treatment of pectus excavatum.

OBJECTIVES:To explore the clinical value of three-dimensional (3D) reconstruction technology combined with 3D printing in the treatment of pectus excavatum (PE).METHODS:The clinical data of 10 patients with PE in our department from June 2018 to December 2020 were analyzed retrospectively. All patients underwent thin-layer computed tomography examination before the operation, and then 3D reconstruction was performed with Mimics 20.0 software. The radian and curvature of the pectus bar were designed according to the reconstructed images. Afterward, the images were imported into the light-curing 3D printer in STL format for slice printing. Hence that the personalized operation scheme, including the size of the pectus bar and the surgical approach, can be made according to the 3D printed model. The thoracoscopic-assisted Nuss operation was completed by bilateral incisions. The operation time, intraoperative blood loss, and postoperative hospitalization were counted and analyzed. The satisfaction of the surgery was evaluated according to the Haller index and the most posterior sternal compression sternovertebral distance.RESULTS:The surgeries were successfully completed in 10 patients without a transfer to open procedure. The average operation time was (56 ± 8.76) min, the intraoperative blood loss was (23.5 ± 11.07) mL, and the postoperative hospitalization was (7.2 ± 0.92) d. There were no serious complications or death during the perioperative period. Compared with the data before the operation, the most posterior sternal compression sternovertebral distance was larger, and the Haller index was lower, the differences were statistically significant (P < 0.05).CONCLUSIONS:3D reconstruction technology combined with 3D printing, which can be used before operation, contributes to the operator performing thoracoscopic-assisted Nuss operation safely and effectively, which has productive clinical application value for the treatment of pectus excavatum.

Parametric finite element analysis to investigate flexural behavior of BFRP-FRC beams

Recently, most of researchers are focusing on the use of ecofriendly and natural fibers for reinforcement in concrete. One of the most recent materials that is being used is Basalt fiber due to its low cost and exceptional characteristics over glass and carbon fibers. This material is tested to be used as alternative to conventional steel reinforcement bars in reinforced concrete structures also. Basalt Fiber-Reinforced Polymer (BFRP) bars are relatively new type of FRP reinforcement material. The present paper is a parametric study for flexural behavior of concrete members reinforced using BFRP rebars using finite element analysis (FEA). FEA software – Abaqus is used for numerical simulation of selected beams. A comparison between experimentally evaluated and numerically obtained load vs midspan deflection response of beam is presented. Due to a good agreement between these two approaches, FE model was used to conduct parametric study. The parameters that were changed from experimentally tested beams are number and size (diameter) of BFRP bars to study effect of reinforcement detailing and reinforcement ratio on load vs. midspan deflection response. A comparison between experimentally determined and numerically evaluated load vs midspan deflection response was carried out and found to be consistent with mean absolute percentage error of 4.80%.

Експериментальне дослідження деформації пружно-гвинтового хона

One of the important issues in the development of agricultural engineering is to increase the efficiency of finishing processes of machining the surfaces of controlling parts of the hydraulic machines equipment and the fuel system of internal combustion engines. High accuracy and quality of parts influence the performance of functional indicators and the consistency of their performance. One of the processes of finishing machining is honing of precision holes. The factor that impacts the accuracy and quality of the machined hole is the ability to influence the process of formation of macrogeometry and microgeometry due to the flexibility of the process. The quality of the micro-relief is influenced by the kinematics of the formation of a grid of traces. The formation of macrogeometry, in turn, is influenced by the principle of formation of geometric production lines, taking into account copying of existing deviations and the transfer of wear of diamond-abrasive bars. To level the impact of existing deviations of the machined hole it is necessary to carry out a flexible control of the process of adjusting the radial size. To ensure the flexibility of the process of honing holes, a helix honing tool is proposed, which eliminates the shortcomings of the existing diamond-abrasive tool by using elastic deformations to increase the radial size and placement of diamond-abrasive bars at an angle of 45º. To study the process of adjusting the radial size of the helix honing tool, the calculated scheme of elastic deformation of the geometric axis and a mathematical model describing the deformation process are presented. An experimental setup of the deformation of the helix honing tool in the axial direction is also given. As a result of the experimental study of the helix honing tool, the theoretical and experimental dependence of the magnitude of the increase in diameter and the force of deformation on the axial elastic deformation is determined. There are also mathematical models obtained as a result of the experimental study of the dependence of the diameter increase on the magnitude of the applied force and axial elastic displacement.

Impact of soil crack on embankment seismic resistance

In general, the soil has low tensile strength and easily collapses when it is subjecting to tensile load. The seismic failure of an embankment has several reasons, among these reasons the low tensile strength of soil is very important and needs enhancement. The seismic load acts as a nonlinearity load in multi-direction, and the tensile load creates by the earthquake has a significant influence on embankment failure. In this study, the impact of soil crack on embankment seismic stability is simulated. The reinforced soil was proposed. Controlling soil crack is the main objective for seismic mitigation of the embankment. The crack extension was studying with an association to the displacement and strain variation in the model. The model numerically simulated by the nonlinear finite element method (NFEM). To integrate results of the nonlinear finite element method (NFEM) the statistical models developed. The results revealed the reinforced soil significantly minimizes displacement and strain energy and improves embankment seismic resistance. The crack on the unsaturated reinforced subsoil was minimizing significantly. The novelty of the present work relates to methodology for identify location of subsoil is needed to be reinforced for minimize cost of construction embankment and improve seismic stability of the embankment-subsoil model. The outcome of this nonlinear numerical simulation predicts the embankment failure mechanism. In soil crack simulation for the embankment, the types of the soil, size of steel bar, and location of the reinforcement can be parameters for future research investigation.

Bond behaviour of deformed steel bars in steel fibre high-strength self-compacting concrete

Research on the bond behaviour between deformed steel bars and the Self-Compacting Concrete (SCC) has been conducted extensively. However, bond study using the high-strength SCC (HSSCC) added with steel fibres is still rare and has not been fully explored. Therefore, in this study, experimental works were carried out to investigate the effects of adding 1% hooked-end steel fibres on the bond behaviour between deformed steel bars and the Steel Fibre High-Strength Self-Compacting Concrete (SFHSSCC) using the direct pullout test method. A total of 39 cubes of HSSCC and SFHSSCC pullout specimens with a dimension of 200 mm were prepared and tested. High-yield deformed steel bars were used as reinforcement bars. The effects of bar sizes (12, 16 and 20 mm diameter), concrete cover (94, 92, 90 and 35 mm thickness), embedment length (3 and 5 times bar diameter) and concrete age (30 ± 2 days and 6 months) towards the mode of failures and bond stress-slip curves were investigated. Coring samples were also taken from the pullout specimen to examine the distribution of the steel fibres. The results showed that size effects in rebars and the concrete cover thickness did not affect the mode of failures for a well-confined SFHSSCC as all bar sizes exhibit the same bond failure, which is pullout failure. More importantly, the addition of steel fibres enhanced the bond ductility in SFHSSCC through the passive confinement effects. The addition of steel fibres to SFHSSCC specimens bonded with 20 mm diameter bars also changed the failure mode from premature splitting to pullout. Meanwhile, the self-flowable SFHSSCC mixture effectively flowed and distributed the steel fibres within the concrete matrix.

Axial performance of seawater sea-sand concrete columns reinforced with basalt fibre-reinforced polymer bars under concentric compressive load

Combined use of basalt fiber reinforced polymer (BFRP) and seawater sea-sand concrete (SSSC) in civil engineering could avoid the consumption of freshwater and river sand and solve the Chloride-induced corrosion problems. To promote the application and development of BFRP bars and SSSC, this paper presents an experimental study on BFRP bar reinforced SSSC columns under axial compression. Eight full-scale SSSC columns reinforced with BFRP bars were tested under axial compression. Failure modes, load–axial deformation curves, lateral deformation distributions, strains in BFRP bars and SSSC, initial axial stiffness, ultimate loads, and ductility of these column specimens were investigated. The effect of tie spacing, concrete strength, reinforcement ratio (i.e., longitudinal bar size) and slenderness ratio on the structural behaviour (e.g., ultimate load, initial stiffness, ductility, and strain distribution) of columns were analysed. Owing to the low modulus of BFRP, strength of BFRP is not fully utilized and the ultimate capacity of columns is mainly controlled by the compressive strength of concrete. Reducing tie spacing could increase the concrete compressive strength due to the confinement effect. Buckling of BFRP bars was postponed by increasing the confinement effect and bar size, resulting in an increase in the ultimate strain in bars. Although the slenderness ratio is low (=10.4–18.9), second-order effect exists in columns as evidenced by the failure modes of columns and the unequal axial strains of BFRP bars in the extreme tensile and compressive sides. Finally, design formulas are proposed to estimate the load-bearing capacity of BFRP bar reinforced SSSC columns and the prediction matches well with the experimental results.

Co@C nanorods as both magnetic stirring nanobars and magnetic recyclable nanocatalysts for microcatalytic reactions

The rapid and effective mixing of reactants and catalysts is essential in liquid-phase catalytic reaction to boost mass transport. However, the routinely used magnetic stirring method is impractical for ultra-small systems such as lab-on-chip and flow cell due to the macroscale size of the magnetic bars. Herein, we developed a facile strategy to synthesize catalytically active magnetic Co@C nanorods, which could serve as both high-performance catalysts and magnetic stirring nanobars for micro-catalytic reactions. The Co@C core-shell structure endows the materials with high catalytic activity and excellent durability, while the strong magnetism of Co nanoparticles renders the nanorod catalyst unique stirring capability under an external rotating magnetic field, which significantly promotes the mass transport and also the catalytic efficiency in micro-catalytic reactions. Inspired by the unique structure and properties, the mixing ability and catalytic activity of Co@C nanorods were evaluated in several systems.