Soft Sleeve Research Articles

Non-destructive evaluation of residual strength distribution of recycled aggregate concrete and bond strength between recycled aggregate concrete and deformed bar with different cover thicknesses after freeze-thaw cycles

The thickness of a cover significantly influences both the bonding performance and the durability of materials against frost resistance. This research investigates the degradation and damage distribution of fundamental mechanical properties in two specimens of recycled aggregate concrete (RAC), each with varying sizes, following freeze-thaw cycles (FTCs). This comparison is facilitated through non-destructive and damage tests. Subsequently, the influence of freeze-thaw damage (FTD) on the bond strength of specimens with differing cover thicknesses is examined via pull-out tests on 14 groups of center pull-out specimens. Lastly, the bond strength is theoretically analyzed. The test results reveal that FTCs diminish the material strength of RAC, and the FTD distribution within RAC specimens is not uniform. The surface concrete sustains a higher degree of damage compared to the internal concrete, resulting in an average FTD of small-size specimens that surpasses that of large-size specimens. The residual strength of RAC can be assessed using a non-destructive test, specifically the ultrasonic wave velocity test. For center pull-out specimens, FTD not only decreases the material strength but also increases the wedge splitting angle while reducing the critical protective layer thickness. This paper proposes a soft sleeve correction theory that comprehensively accounts for the effects of FTD. When combined with non-destructive test results—namely those from the ultrasonic wave velocity test—this theory can effectively evaluate the bond strength of RAC post-FTD. This approach offers valuable insights for the design and assessment of recycled concrete in cold climates.

Development and Testing of Novel Soft Sleeve Actuators

Development and Testing of Novel Soft Sleeve Actuators

All-Suture Anchors in Orthopaedic Surgery: Design, Rationale, Biomechanical Data, and Clinical Outcomes

All-suture anchors (ASAs) are a relatively new alternative to traditional suture anchors, comprised of sutures, suture tapes, or ribbons woven through a soft sleeve. These novel anchors are typically smaller than traditional anchors, allowing for more anchors to be used in the same amount of space or for use when bone stock is limited, for example, in revision settings. They can be inserted through curved guides to reach more challenging locations, and they have thus far had similar loads to failure during biomechanical testing as traditional anchors. However, these benefits must be weighed against new challenges. When using ASAs, care must be taken to fully deploy and seat the anchor against cortical bone for optimal fixation and to prevent gap formation. Furthermore, decortication, often performed to enhance the biologic environment for soft-tissue healing, may weaken the cortical bone on which ASA fixation depends on. The purpose of this article is to provide insight on the designs, advantages, and potential disadvantages associated with ASAs, as well as review the available biomechanical and clinical data.

Sitting or Standing Data Acquisition Based Breast Ultrasound Computed Tomography

Ultrasound computed tomography (UCT) is a promising approach for early breast cancer screening. However, current studies which use prone posture to collect breast ultrasonic data cause four problems, a long non-data-acquisition time, inconvenient, possible chances for cross infection, and a large area occupied by equipment. The purpose of this study is to estimate a complete breast UCT image by using sitting or standing data acquisition, which can obtains a more rapid, convenient and sanitary examination process, and a less space occupied by equipment. Therefore, this study proposes a sitting or standing data acquisition based breast UCT method, which is a more practical data acquisition method for breast UCT. This study places a uniform soft sleeve on the outside of the breast so that it would not be deformed significantly due to the change of body posture. Because the soft sleeve is an influencing factor from outside for breast imaging, this study discusses the considerations for selecting that. Computer simulations are conducted to prove the effectiveness of the proposed method. Results suggest that, by using a soft sleeve whose sound speed is between 1450m/s and 1550m/s, the proposed method is effective; the biases of the reconstructed images are less than 1% under the 5% noise condition.

Endaural Endoscopic Atticoantrotomy (Retrograde Mastoidectomy) using a Constant Suction Bone-drilling Technique.

Endoscopic middle ear surgery is a widely employed minimally invasive surgical technique to address middle ear and mastoid pathology. Bone drilling is the main technical challenge of endoscopic middle ear surgery. The accompanying video describes the detailed protocol of a constant-suction bone-drilling technique and the procedure of endaural exclusive endoscopic atticoantrotomy (retrograde mastoidectomy) using this technique. The main components of this bone-drilling technique include a soft and flexible suction tube, which is placed into the tympanic cavity to provide constant suction, and a soft sleeve, which is wrapped around the drill shaft to prevent the high-speed rotating shaft from damaging the lens of the endoscope. With these simple modifications, the traditional otological electrodrill can be used for drilling a tiny endaural incision in endoscopic middle ear surgery. Based on this bone-drilling technique, endaural endoscopic atticoantrotomy (retrograde mastoidectomy) can be successfully established for the removal of various amounts of bone, depending on the extent of the lesion. The short-term postoperative outcome seems promising.

Endaural Endoscopic Atticoantrotomy (Retrograde Mastoidectomy) using a Constant Suction Bone-drilling Technique

Endoscopic middle ear surgery is a widely employed minimally invasive surgical technique to address middle ear and mastoid pathology. Bone drilling is the main technical challenge of endoscopic middle ear surgery. The accompanying video describes the detailed protocol of a constant-suction bone-drilling technique and the procedure of endaural exclusive endoscopic atticoantrotomy (retrograde mastoidectomy) using this technique. The main components of this bone-drilling technique include a soft and flexible suction tube, which is placed into the tympanic cavity to provide constant suction, and a soft sleeve, which is wrapped around the drill shaft to prevent the high-speed rotating shaft from damaging the lens of the endoscope. With these simple modifications, the traditional otological electrodrill can be used for drilling a tiny endaural incision in endoscopic middle ear surgery. Based on this bone-drilling technique, endaural endoscopic atticoantrotomy (retrograde mastoidectomy) can be successfully established for the removal of various amounts of bone, depending on the extent of the lesion. The short-term postoperative outcome seems promising.

Neochloris oleoabundans oil production in an outdoor tubular photobioreactor at pilot scale

Oil production was tested with Neochloris oleoabundans in a 6 m3, horizontal soft sleeve tubular reactor from 22 October to 7 November in Matalascañas, southern Spain. Biomass productivity during the nitrogen replete phase was 7.4 g dw m−2 day−1. Maximum lipid content in the biomass was 39% and average lipid productivity during the nitrogen depletion phase was 2.0 g m−2 day−1. Nitrogen depletion of the cultures was carried out in order to enhance fatty acid formation, using the inverse nitrogen quota in the biomass to predict the fatty acid content. TFA concentration at harvest was 14% DW, compared to a value of 17%, predicted by the inverse nitrogen quota. The overall feasibility of the horizontal tubular technology for microalgal oil production, including mixing energy expenditure, was evaluated.

Semiextended approach for intramedullary nailing via a patellar eversion technique for tibial-shaft fractures: Evaluation of the patellofemoral joint

Intramedullary nail fixation is a common treatment for tibial-shaft fractures, and it offers a better functional prognosis than other conservative treatments. Currently, the primary approach employed during intramedullary nail insertion is the semiextended position is the suprapatellar approach, which involves a vertical incision of the quadriceps tendon Damage to the patellofemoral joint cartilage has been highlighted as a drawback associated with this approach. To avoid this issue, we perform surgery using the patellar eversion technique and a soft sleeve. This method allows the articular surface to be monitored during intramedullary nail insertion. We arthroscopically assessed the effect of this technique on patellofemoral joint cartilage. The patellar eversion technique allows a direct view and protection of the patellofemoral joint without affecting the patella. Thus, damage to the patellofemoral joint cartilage can be avoided.

Static and dynamic behaviour of compacted sand and clay: Comparison between measurements in Triaxial and Oedometric test systems

ABSTRACTIn rock mechanics and rock physics, like in many other branches of research, it is important to compare results obtained in different kinds of apparatus that are meant to measure the same properties. Differences may in general be due to differences in samples, or in test procedures. Here we compare uniaxial compaction experiments in oedometric and triaxial tests systems, using brine‐saturated samples made from pure kaolinite or from Ottawa sand. Small differences in sample manufacturing or in initial loading of the specimens were found to cause significant differences in static behaviour and in ultrasonic velocities during the tests. The influence of differences in sample geometry (wide and thin samples in the oedometer versus long and slim samples in the triaxial set‐up) and the influence of different boundary conditions caused by the confining medium (steel in the oedometer, thin soft sleeve in the triaxial system) were studied, amongst others with the use of discrete particle modelling. Although the boundary conditions may have an influence, the most significant sources of discrepancy in our experiments were associated with the manufacturing and preparation of the samples to be tested. The test data show that the drained static compaction modulus for sand is close to its dynamic counterpart, while for kaolinite, the dynamic modulus is significantly larger than the static one.

Simplified Anchor System for CFRP Rods

AbstractThe increased use of carbon fiber–reinforced polymer (CFRP) rods in prestressed concrete applications has been challenged by identifying a suitable anchor system. To overcome such a challenge, the design of a simplified anchor system composed of three wedges and a barrel, without a soft sleeve, is presented to duplicate the simplicity of the widely utilized anchor systems in steel strands. A numerical study and experimental verification of the simplified anchor system for a CFRP rod are presented. Three-dimensional (3D) finite-element modeling has been conducted on the anchor system consisting of isotropic steel wedges and barrel, in addition to an orthotropic CFRP rod. The wedges and barrel are modeled as elastoplastic materials of different hardness. The rod/wedge and wedge/barrel interfaces are simulated using surface-based contact models having different coefficients of friction. Two hardness levels [171 and 319 Vickers hardness numbers (VPN)] are considered for the wedges. When the softer wed...

Cu/Al 및 Fe/Al 층상복합재료 압출공정에서 구성재료의 불균일 변형

This paper is concerned with the analysis of plastic deformation of bimetal co-extrusion process. Two sets of material combination have been adopted for analysis, i.e. combinations of Cu/Al and Fe/Al. In the first set of material combination, the selected materials are AA 1100 aluminum alloy as hard material and CDA 110 as soft one. This type of material selection is to examine the effect of hard core and soft sleeve and vice versa on the deformation pattern in terms of plastic zone and velocity discontinuity along the contact surface between construction materials. Four different cases of co-extrusion process in terms of material combination and interference bonding were simulated to investigate the effect of material arrangement between core and sleeve, and of bonding on the plastic zones and velocity discontinuity. In the other set of material combination, model materials used as core and sleeve were AA 1100 and AISI 1010, which are relatively soft and hard, respectively. Process parameters except diameter ratio of core to sleeve material such as semi-die angle, reduction in area in global sense and die comer radius have been set constant throughout the simulation to concentrate our effort on the analysis of influence of diameter ratio on deformation behavior such as deformation zone, surface expansion, exit velocity discontinuity between composite materials, and extrusion forces.

Deformation Analysis of Co-Extrusion Process of Aluminum Alloy and Copper Alloy

This paper is concerned with the analysis of plastic deformation of bimetal co-extrusion process. Extrusion is related to large deformation of material and leads to non-homogeneous deformation within work-piece material. The mechanism of plastic deformation during the composite rod extrusion is much more complicated than that in single metal extrusion. Deformation patterns of co-extrusion of two different materials are characterized by several process parameters. In this paper, the analysis is focused to investigate the effect of contact conditions along the interface between two different materials. The rigid-plastic finite element method was applied to the analysis of co-extrusion process. The selected materials are AA 1100 aluminum alloy as hard material and CDA 110 as soft one. This type of material selection was to examine the effect of hard core and soft sleeve and vice versa in terms of deformation pattern. The initial composite billets were prepared by inserting the core material in tight (0.023mm) and weak (0.012mm) interference bonding, respectively. Four different cases of co-extrusion process in terms of material combination and interference bonding were simulated to investigate the effect of material arrangement between core and sleeve, and of bonding on the plastic zones. It is concluded from the simulation results that the plastic zones in this co-extrusion process are not influenced much by the selection of material arrangements or bonding condition between construction materials. However, it was seen from the simulation results that the extrusion ratio of each construction material, i.e. homogeneity of co-extrusion, depends much on the material arrangement and the bonding condition.

Effect of rod profile and strength on the contact behavior of CFRP–metal couples

Abstract The interfacial mechanics of CFRP–metal couples under different contact pressures was studied by considering different composite surface profiles and strengths. The composite rods were in contact with either annealed or as-received aluminum or copper sleeves. The contact shear stress was found to increase significantly when a smooth machined CFRP rod was used. By removing surface perturbations of the rod, the actual contact area increased allowing more mechanical interlocking to take place. The shear stress also increased when a stronger CFRP rod was used especially with a soft sleeve.

Drawing of a material consisting of a hard core and a soft sleeve

This paper examines the drawing of a bimetal wire, the peculiarity of which consists of a weak sleeve and a comparatively strong core. This material can serve to model the drawing of a wire coated with a solid lubricant: sometimes the lubricant is shaved off during drawing, which is, of course, an undesired phenomenon in practice. Conditions for shaving and for sound flow (i.e. where the lubricant flows through the drawing die) are discussed as a function of process variables.