Hollow Tube Research Articles

Characterization of Mg–9Al–1Zn-0.2Mn alloy tubes processed by a new modified tube cyclic expansion extrusion (M-TCEE) process

In this study, a new modified tube cyclic expansion extrusion process named M-TCEE was utilized for producing tubes with ultrafine grained (UFG) microstructure and improved properties. In M-TCEE process, the utilization of a moving mandrel inside the hollow tube during the process provides the possibility of using bulk rod-shaped punch, instead of hollow tubular punch which has been used in conventional TCEE process. This leads to that a higher pressing load can be applied to the material without the risk of punch buckling. So, the production of longer and larger tubes, which needs a higher required pressing load, can be performed easier in M-TCEE process. In current study, the capabilities of M-TCEE process in improving microstructure, mechanical properties and corrosion resistance of the Mg–9Al–1Zn-0.2Mn magnesium alloy tubes were investigated. The results showed that after two passes of M-TCEE process, the yield strength increased from 36 MPa to 137 MPa (3.8 time greater), the ultimate tensile strength increased from 73 MPa to 265 MPa (3.6 time greater) and the ductility was enhanced from 11.2% to 20.2% (1.8 time greater). Three passes of M-TCEE led to improving hardness from 54 HV to 99 HV (1.83 time greater). Also, corrosion results revealed the capability of the M-TCEE process in improving the corrosion resistance of AZ91 tubes. It seems that the M-TCEE process can produce ultrafine-grained AZ91 magnesium alloy tubes with significant mechanical properties and improved corrosion resistance.

Ternary hierarchical structure based solar‐driven evaporator for long‐lasting concentrated brine treatment

AbstractSolar‐driven evaporation has been a promising desalination method for treating concentrated seawater, since it is cost‐effectiveness, simplicity, and environmentally friendly. However, this method faces an unavoidable long‐term problem that the salt generated in the evaporation processes would affect and hinder its evaporation efficiency. Because the salt inevitably crystallizes on the surface of photothermal evaporation materials, and this crystallization process increases with time to impair the material area of the sunlight absorption and evaporation. Here, we show a ternary hierarchical structure based solar‐driven evaporator that reduces the evaporation material surface coverage of the salt to get long‐lasting concentrated brine treatment capacity. This evaporator is constructed by plugging vertically arranged hollow tube arrays across a porous plate. The top, middle, and bottom of the evaporator respectively serve as the salt crystallization site, the evaporation site, and the light absorption site. Meanwhile, the self‐cleaning of the evaporator can be achieved by back diffusion of the crystallized salts. As a result, this efficient and durable evaporator exhibits freshwater production of 10.21 kg/(m2·day) in outdoor experiment in the treatment of the concentrated natural seawater (21.3 wt%).image

Bimetallic Fe, Ni-PBA on hollow graphite tube for capacitive deionization with exceptional stability

Faradic materials become more and more attractive for capacitive deionization (CDI) due to their high ion adsorption capacity. However, it is still a great challenge to design a stable and high charge-transfer rate material for high-performance desalination. Herein, we report a bimetallic Fe, Ni-doped Prussian blue analogue (PBA)-packed hollow graphite tube (FeNiHCF@HGT) electrode for boosting the CDI performance. The high conductivity of HGT and the tight adhesion of PBA crystals on HGT endow the FeNiHCF@HGT electrode with fast charge-transfer, excellent redox activity and high stability through buffering the crystal deformation of PBAs in the ion-intercalation/deintercalation process. In addition, the bimetallic Fe, Ni-doping in PBA at the high-spin (HS) sites enhances the redox activity of FeIIC6/ FeIIIC6 in FeNiHCF with Ni substitution for partial HS Fe. Under the optimal Ni-doping condition, the obtained Fe1Ni1HCF@HGT delivers a high specific capacity and superior rate performance (364F g−1 at 1 A g−1, 88.2% retention at 20 A g−1), with an ultra-high surface capacitance contribution (92.3% at 20 mV s−1). The CDI results demonstrate its outstanding salt adsorption capacity (60.2 mg g−1 in 100 mM NaCl) and exceptional cycle stability (106.6% retention after 100 cycles). This new strategy with the synergy of conductive tube matrix and Ni substitution at PBA lattice sites fully achieves the high-performance CDI.

Boron nitride hollow microtube with nanosheets directionally covering the tube wall: Preparation and adsorption property

In this paper, a novel boron nitride hollow microtube (BNHM) structure by annealing assisted high-pressure etching method. The products were characterized by XRD, FTIR, Raman, XPS, SEM, TEM, TGA, BET, UV–vis, and PL. The result shows that the sample displayed a one-dimensional hollow tube structure directionally covered with nanosheets. The average inner diameter of the hollow tube is 1 µm with a length of 2–4.5 µm. And the wall thickness of the hollow tube structure is about 100 nm. In addition, the band gap value of the sample is 5.51 eV presenting the strongest absorption peak at 225 nm. The specific surface area of the sample is 272.6 m2·g−1, showing good adsorption efficiency on Congo red (absorbed 75% in 5 min). Meanwhile, the possible growth mechanism of BNHM is also discussed.

Hot Rolling of ZK60 Magnesium Alloy with Isotropic Tensile Properties from Tubing Made by Shear Assisted Processing and Extrusion (ShAPE)

In the present work, we utilized Shear Assisted Processing and Extrusion (ShAPE), a solid-phase processing technique, to extrude hollow tubes of ZK60 Mg alloy. Hot rolling was performed on these as-extruded tubes (after slitting them longitudinally) to thickness reductions of 37%, 68%, and 93% to investigate their viability as rolling feedstock material. EBSD analysis showed the formation of twinned grains in the ShAPE processed material and a gradual re-orientation of the basal texture parallel to the extrusion direction with each rolling step. Moreover, an equiaxed grain size of 5.15 ± 3.39 μm was obtained in the ShAPE extruded material, and the microstructure was retained even after 93% rolling reduction. The rolled sheets also showed excellent tensile strengths and no mechanical anisotropy, a critical characteristic for formability. The unique microstructures developed and their excellent mechanical properties, combined with the ease of scalability of the process, make ShAPE a promising alternative to existing methods for producing rolling feedstock material.

Energy absorption characteristics of the bionic lotus petiole structure under transverse load

Porous structures are often used as energy absorbing devices due to their light weight and high strength; therefore, the mechanical properties and collapse behavior of porous structures under various loads have attracted much attention. In this paper, two bionic lotus petiole structures: 12-wells original structure (Os-12w) and 13-wells original structure (Os-13w) are proposed to improve the energy absorption properties of porous structures, which are inspired by the light weight and collapse resistance of lotus petiole. Then a comparative study of Os-12w, Os-13w, hollow square tube and hollow circular tube based on quasi-static mechanical experimentally(loading speed is 3 mm/min) validated finite element models was carried out to explore the energy absorption characteristics of different structures under lateral loading. The results showed that the specific energy absorption (SEA) of Os-12w and Os-13w increased by about 88.9% and 77.8%, respectively, and the crushing force efficiency (CFE) increased by about 178.8% and 178%, respectively, compared with the hollow square tube. Compared with the hollow circular tube, the peak crushing force (PCF) of Os-12w and Os-13w were reduced by about 28.2% and 36.8%, respectively. Collectively, Os-12w has a greater energy absorption potential than Os-13w. The simulation results of the experiment explain why the energy absorption performance of the bionic structure is better than that of the hollow tube. Then, through further simulation analysis, the effects of the bearing angle and quarter windmill-like structural parameters on the energy absorption characteristics of Os-12w were explored. Valuable suggestions and guidance are provided for the subsequent development of thin-walled porous structures.

Design optimization of an optical fiber air-backed concentric hybrid mandrel hydrophone by an iterative design and finite element analysis for submarine passive array applications

The optical fiber hydrophones are well suited for the submarine passive sonar applications taking into consideration of their high sensitivity, fully electrically passive characteristics etc. and are definitely an equivalent replacement for Lead Zirconate and Lead Titanate ceramic hydrophones. In this paper, finite element analysis of several sets of cases of concentric hybrid material-based air-backed OF mandrel hydrophones are analysed and tuned to their geometric dimensions and their mechanical properties for design optimization, suitable for submarine sonar applications. A finite element method is adopted for analysis, strain and sensitivity calculations using ANSYS software. An inverse dependency of the sensitivity and the natural frequency were observed and was overcome by an innovative method where a hybrid inner hollow tube, combining both Aluminium and high-density polyethylene materials, were used, improving both the stiffness property and compliance of the mandrel and thereby improving both the natural frequency and pressure sensitivity. The harmonic analysis was carried out at 5 KHz acoustic pressure, by adding hydrostatic pressures of 2 MPa, 3 MPa and 4 MPa and obtained satisfying results. The acoustic directivity of this OF mandrel hydrophone was estimated, plotted and an omni directional pattern was obtained.

Emission control using Carbon Silencer

: For the purpose of mitigating emission and noise in an automotive exhaust system, a carbon silencer is utilized. It is assembled using a perforated hollow metal tube, external casing, activated charcoal and a solution of limestone. The engine's exhaust pipe is connected to the carbon silencer. The hazardous sulfur oxides and nitrogen oxides elements generated by the engine are filtered by activated charcoal. Compared to sound produced in a traditional silencer, sound produced within limestone water is less audible. This is primarily due to little sprockets in water molecules, which reduces its amplitude and hence the sound level. Due to the presence of activated charcoal which has more surface area than regular charcoal it is known as Carbon Silencer. When tested in a single cylinder 4-stroke petrol engine, the noise and smoke levels are significantly lower compared to a typical silencer. Automobiles contribute the majority of pollutants, which include carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), and lead. Other sources include electric power plants, industrial and household fuel usage, trash burning, and industrial processes. Carbon silencers are used to decrease emissions and noise

Hollow 1D carbon tube core anchored in Co3O4@SnS2 multiple shells for constructing binder-free electrodes of flexible supercapacitors

The design of the core@multi-shell metal sulfide hollow tube is of great importance for various supercapacitor electrodes. Herein, a hollow carbon tube (HCT) core@multi-shell with rich pores is developed for constructing the binder-free flexible electrodes (HCT-x@Co3O4@SnS2). The inner core–shell is derived from the zeolitic imidazole framework (ZIF)-8@ZIF-67 porous carbon tube and is engineered with vertically aligned SnS2 nanosheets. The unique inner core–shell and the outer-shell SnS2 contribute to the excellent characteristics, including abundant pores and channels for the rapid ion transport and storage, high specific surface area, improved electrical conductivity, and additional electroactive sites for the faradaic reaction. Thanks to the synergies between the unique 1D porous hollow structure and the different components, the as-fabricated HCT-2@Co3O4@SnS2 electrode exhibits a high specific capacitance of 439 F/g at 1 A/g. Moreover, the assembled flexible supercapacitor also demonstrates a remarkable energy density of 40.22 Wh kg−1, the corresponding power densities of 750.22 W kg−1, and long cycle life. In addition, no structural deformation and capacitance loss are observed in the bended devices. The developed approach provides a facile structure design route for the flexible binder-free electrode preparation of flexible energy storage applications.

A comparative study on structural analysis of 3-PRS Tri-Glide, 3-PRR and 3-PRS Tripod parallel kinematic machines for angular drilling applications

Parallel kinematic machines are a result of intensive research and development in the area of high speed machining (HSM). The high stiffness and low inertia characteristics of the parallel kinematic architecture make it suitable for high speed machine tool. This research aims to compare the structural characteristics of 3-DOF Tri-Glide and Tripod Parallel Kinematic Machines (PKMs) by varying the geometrical parameters of their links. Both solid and hollow tube structures are considered to evaluate the stiffness of the PKMs. Initially, mild steel is used for this comparative study. Later, mild steel is replaced by aluminium alloy due to its high strength to weight ratio. The 3PRS Tri-Glide, 3PRS and 3PRR Tripod models are modeled and analyzed using the Finite element software package ANSYS. Based on the structural analysis the results are compared and summarized.

Microstructure regulation of graphitic carbon nitride nanotubes via quick thermal polymerization process for photocatalytic hydrogen evolution

Among multitudinous photocatalytic materials, graphite carbonitride (g-C3N4) has been widely explored as a new photocatalyst. The g-C3N4 nanotubes with hollow one-dimensional structure can promote carrier migration along the one-dimensional direction, thereby improving the electron-hole separation efficiency, which has always been a hot spot. However, the collapse of nanotubes in long-term thermal polymerization process leads to the decline of photocatalytic performance, which is expected to be further optimized. Herein, we report g-C3N4 nanotubes (TCN) through short time thermal polymerization to ensure the integrity of g-C3N4 skeleton. And the influence of thermal temperature on the internal formation mechanism of nanotube morphology is investigated. Combined with the unique hollow tube structure and complete framework, the migration of photogenerated carriers is significantly accelerated and the photocatalytic hydrogen evolution performance is improved more than 7 times compared with the original g-C3N4. This work provides novel insights into the preparation of g-C3N4 nanotubes for photocatalytic applications.

Experimental Study on the Influence of Stress Concentration on the Flexural Stability of Aluminum Hollow Tube

Solid sections are gradually replaced by the hollow sections in most of the structural applications in various engineering fields due to their attracting features such as light-weight and high specific strength. In the present investigation, one such attempt was made to investigate in detail about the flexural capability of an aluminum hollow tube (AHT) with square cross section. The objective of the investigation is to study about the influence of stress concentration on the flexural behavior of the hollow tube. The type of stress concentration considered in the investigation was through hole of different cross section and quantity. Three-point bending test with concentrated load is conducted on the specimens of hollow tube with different types of stress concentration such as circular hole, square hole and perforations. The load was applied manually during the bending test. The bending test was carried out on all specimens for various support span of 110, 130, 170 and 200 mm respectively. The output measures of the study are maximum bending load, deflection and flexural stiffness. The maximum bending load capacity around 5.7 kN was observed for AHT with circular hole with support span of 90 mm. The maximum deflection measured at the mid span of the beam increases rapidly when the aspect ratio increases from 73.33 to 93.33, whereas after which the variation of deflection is marginal for the increase in aspect ratio from 113.33 to 133.33. This was due to the effect of spring back, which dominates more on the bending behaviour at shorter span between the supports

Experimental studies on the axial compression behavior of hollow sandwich concrete GFRP-steel tube composite short columns

This paper explores the mechanical mechanisms and properties of hollow-sandwich concrete GFRP–steel tube composite short columns under axial compression to promote their application in the practical engineering of bridge piers under high-salinity and high-humidity corrosion environments. The force action, stress state and mechanical calculation model of composite short columns are important manifestations reflecting the mechanical mechanism, and the mechanical properties are measured by failure characteristics, bearing capacity, initial stiffness, ductility coefficient, energy dissipation value, damage coefficient and load–displacement curve. In this paper, an axial compression test of 15 composite short columns was designed and carried out with the parameters of section form, GFRP tube thickness, concrete strength, hollow ratio and steel tube thickness. The results showed that the specimens exhibited typical local pressure or shear failure, which is characterized by tearing of the GFRP tube fiber. The built-in steel tube can improve the ultimate bearing capacity of the specimen, and the ductility and axial compression energy dissipation of the double-tube concrete short column (DTCC) is basically consistent with hollow sandwich concrete GFRP-steel tube composite short columns (DSTCs). With a reasonable hollow ratio, the DSTCs can meet the same mechanical properties and deformation performance requirements as the DTCC. Compared with concrete strength and steel tube thickness, the influence of GFRP tube thickness and hollow ratio on the ultimate bearing capacity of specimens is more obvious. Under the action of axial compression, the sandwich concrete is changed from a unidirectional compression state to a complex three-dimensional compression-confined concrete. The GFRP tube and steel tube change from unidirectional compression to a bidirectional stress state. Based on the plastic theory analysis, considering the influence of uneven distribution of the concrete stress state along the radial direction, the calculation model of axial compression bearing capacity of hollow sandwich concrete GFRP-steel tube composite short columns is derived. The calculation results are in good agreement with the experimental results.

Mechanical Modelling of the Strength and Stiffness of Circular Hollow Section Tube under Localised Transverse Compression and Tension

The component method is a powerful tool for designing and modelling steel beam-to-column connections. Its widespread use is ensured by several formulations currently included in Eurocode 3 part 1.8 for welded and bolted joints. However, the recent use of 3D Laser Cutting Technology (3D-LCT) in the construction market has enlarged the range of solutions, allowing the realisation of tubular columns with passing-through elements. Given the recent development, no design formulations are currently provided for this typology. At this moment, only a few research studies have developed to fill this knowledge gap. At the University of Salerno, since some years, research efforts are ongoing to characterise the flexural strength of connections between Circular Hollow Section columns and passing double-tee beams, suggesting methodologies to predict the behaviour of the resistance and stiffness of this typology and some of its elementary joint components. Within this framework, this paper aims to examine the strength and stiffness of one of the main components of this joint, which was never examined previously, that is the so-called tube under localised transverse tension/compression. Design formulations are derived from a parametric study carried out through numerical simulations of several geometric configurations.

Biological response of 3D-printed β-tricalcium phosphate bioceramic scaffolds with the hollow tube structure

It is a large clinical challenge to repair critical-size bone defects, and vascularization in the early stage is of vital importance in bone regeneration. In recent years, 3D-printed bioceramic is a kind of common bioactive scaffold for repairing bone defects. However, conventional 3D-printed bioceramic scaffolds consist of stacked solid struts with low porosity, which limits the ability of angiogenesis and bone regeneration. The hollow tube structure can induce endothelial cells to build the vascular system. In this study, β-tricalcium phosphate (β-TCP) bioceramic scaffolds containing the hollow tube structure were prepared with digital light processing-based 3D printing strategy. The physicochemical properties and osteogenic activities of prepared scaffolds could be precisely controlled by adjusting the parameters of hollow tubes. Compared with solid bioceramic scaffolds, such scaffolds could significantly improve the proliferation and attachment activity of rabbit bone mesenchymal stem cells in vitro, and facilitate early angiogenesis and subsequent osteogenesis in vivo. Therefore, β-TCP bioceramic scaffolds with the hollow tube structure possess great potential application for the treatment of critical-size bone defects.

Effects of the triangular hollow tubes structure and carbon coating on the lithium storage performances of Co3O4/NiO microspheres

Co3O4/NiO@C (CNOT@C) microspheres were synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere. A high initial reversible specific capacity of 1469.7 mA h g−1 of CNOT@C was attained due to its high specific surface area from its unique triangular hollow tube morphology. These triangular hollow tubes relieved volume expansion from repeated cycling processes, with CNOT@C attaining a high reversible specific capacity of 694.9 mA h g−1 after 1000 cycles at 6000 mA g−1. Furthermore, excellent rate performance of CNOT@C was achieved due to its carbon layer coating, exhibiting a reversible specific capacity of 429.8 mA h g−1 at 10 000 mA g−1.

"A New Single Use Needle for Simultaneous Bone Marrow Aspiration and Trephine (Core) Biopsy Utilizing the Same Needle and Same Entry Site While Maintaining the Specimen Quality"

A needle is described for use in simultaneously taking a bone marrow aspirate and a core biopsy sample without sacrificing the quality of either specimen from the posterior iliac crest. The needle comprises a hollow tube with a front-end portion formed to a reduced diameter.

Synthesis of FeOOH scaly hollow tubes based on Cu2O wire templates toward high-efficiency oxygen evolution reaction

Synthesis of FeOOH scaly hollow tubes based on Cu2O wire templates toward high-efficiency oxygen evolution reaction

Experimental and numerical study on the prefabricated double L-shaped beam-column joint with triangular stiffener

This study proposes an innovative prefabricated double L-shaped beam-column joint with triangular stiffener (double L-shaped joint) for low-rise residential buildings. The double L-shaped joint consists of the L-shaped connector with triangular stiffener, web side plate connection, H-shaped beam, and concrete-filled lightweight steel tube (CFLST) column or square hollow steel tube (SHS) column. Twelve double L-shaped joints are manufactured and experimented. The design parameters include the column types (CFLST or SHS), triangular stiffener height, perforated end plate (with or without), and the web side plate connection (with or without). In addition, the failure modes, hysteretic performances, ultimate capacity, stiffness degradation, deformation capacity, energy dissipation, and strain responses of joint specimens are analyzed. The experimental results show that the failure modes include steel tube local buckling, weld cracking, and bolts fracture in the area of the L-shaped connector. The ultimate moment of the CFLST column joints rises from 4.53% to 13.05% compared to the SHS column joints, while the initial stiffness increases from 2.16% to 26.46%. The perforated end plate grows at the ultimate moment, but the ductility index reduces. The initial stiffness and deformation capacity of the specimens without a web side plate connection decreases significantly. The finite element model is developed, and the numerical simulation is conducted. The experimental results are consistent with failure modes and bending moment versus rotation angle curves obtioned by numerical simulation.

Analysis of hollow aluminum square tube of refitted mattresses using mathematical calculation & computerized 3-dimensional development

Analysis of hollow aluminum square tube of refitted mattresses using mathematical calculation & computerized 3-dimensional development