Tension Device Research Articles

Lung Tensioning Device Coil Treatment in Patients with Severe Emphysema: A Prospective Safety and Feasibility Trial (EFFORT)

Introduction: Currently, there is a lack of bronchoscopic lung volume reduction options that do not depend on fissure integrity. Endobronchial coils have been extensively studied to address this need but exhibited variable patient response and have been discontinued. Lung tension device (LTD) coils represent the next-generation coil treatment. This study aimed to evaluate safety, feasibility, and efficacy of LTD-coil treatment. Methods: Patients with advanced emphysema and hyperinflation were enrolled at two European sites. LTD-coils (Free Flow Medical, Fremont, CA, USA) were implanted in the two most destructed lobes, as determined by quantitative CT analysis, in two separate procedures. The primary endpoint was 3-month follow-up after the last treatment. Results: Fourteen patients (50% male, median age 64 years, FEV1 23%predicted, RV 249%predicted) received LTD-coil treatment: 12 received bilateral and 2 unilateral treatment. Six serious respiratory adverse events occurred within the initial 3 months posttreatment, including one device-associated death. Treatment significantly reduced in- and expiratory volume of the treated lobes (−410 [−710, −340], p = 0.004 and −650 [−730, −190] mL, p < 0.001, respectively) and improved quality of life (SGRQ total score −4.6 [−21.0, −2.6], p < 0.001). However, at a group level, no significant improvements in pulmonary function or 6-min walk distance were observed. Responder rates ranged from 18% to 54% for the different endpoints. Conclusion: This first-in-human study shows that the new LTD-coil procedure is feasible with a safety profile comparable to the previous coil treatment. While the treatment effectively reduced lobar volume and modestly improved quality of life up to 3 months’ follow-up, at a group level it did not significantly enhance pulmonary function or exercise capacity.

AN IN VITRO STUDY EXAMINING WIRE TENSION IN FINE WIRE CIRCULAR EXTERNAL FIXATION CONSTRUCTS

IntroductionIlizarov fixators are reliant on tensioned fine wires for stability. The tension in the wires is generated using specific tensioning devices. Loss of wire tension over time may lead of loss a stability and complications. A series of in vitro experiments were undertaken to explore wire tensioner accuracy, the impact of fixation bolt torque and initial tension on loss of tension in ilizarov constructs under static and dynamic loads.Materials &amp; MethodsMedical grade materials were applied to a synthetic bone analogue using surgical instruments in all experiments. Bolt torque was fixed at 6, 10 or 14 Nm using a torque limiting wrench. Wire tension was assessed using a strain measurement bridge. Wires were tensioned to 90, 110 and 130kg as measured by a commercial dynamometric tensioner. Static and dynamic testing was undertaken using an instron testing machine. Cyclical loads from 50–750N were applied for 5000 cycles.ResultsActual wire tension was approximately 15% less than indicated by the tensioner device. Using fixation bolt torques of 10Nm and 14Nm achieved final wire tensions of around 60% and 80% of that applied at 90 and 130kg of applied tension. Static load testing demonstrated self stiffening to similar levels in all pre-tensions. Dynamic testing demonstrated significant loss of tension, most of which occured in the first 3 cycles, inversely proportional to the tension initially applied.ConclusionsThese experiments provides insight into the effect of initially applied wire tension on Illizarov mechanical performance. It is important surgeons understand how the different ways that these devices are applied affects mechanical performance. Further research examining what factors affect performance across different manufacturers equipment would therefore be relevant, alongside the development of novel fixation methods to reduce wire slippage and the further development of equipment for clinical use.

Tests and Seismic Response Analysis of Guided-Rail-Type Anti-Tensile Rubber Bearing

When subjected to seismic activity, tall isolated buildings with a high aspect ratio are susceptible to overturning as a result of the failure of rubber isolation bearings under tension. In order to address this issue, a guided-rail tension device (GR) has been developed to enhance the tensile strength of rubber bearings. Furthermore, a novel guided-rail isolation rubber bearing (GR&amp;RB) has been proposed as a potential solution. Quasi-static tests have been conducted to investigate the mechanical properties of the GR, as well as the GR&amp;LNR600 and LNR600. Additionally, numerical finite element analysis has been employed to study the seismic response of the GR&amp;RB under El Centro seismic action in a high-rise building with an aspect ratio of approximately 4. The experimental results suggest that the inclusion of GRs has a limited effect on the horizontal mechanical attributes of rubber isolation bearings. Nevertheless, it simultaneously enhances their tensile strength, demonstrating a significant augmentation of 4.23 times. Moreover, the mechanical behavior of the GR aligns with the Hook model. The numerical analysis suggests that the utilization of GR&amp;RB can mitigate the tensile stress levels of rubber isolators. Furthermore, it is recommended to augment the elastic tensile stiffness of the GR while reducing the open value to enhance the tensile efficiency, with the potential to attain up to 75% efficiency in tensile performance.

Effect of Breadfruit (Artocarpus Altilis) Leaf Extract on Blood Pressure in Obese Adults in Makassar, Indonesia

Background: Obesity has become a global public health and nutrition problem. Obese people will have a variety of diseases, one of which is high blood pressure. Therefore, this study aims to determine the effect of breadfruit leaf extract on blood pressure in obese adults in Makassar City. Methods: An experimental study was conducted involving a double-blind, randomized controlled trial with pretest and posttest assessments, which included 36 obese respondents. The intervention group received breadfruit leaf extract in the methodology, while the control group received a placebo capsule. Blood pressure was monitored using a digital tension device. Data analysis was performed using SPSS 13, including paired tests, independent tests, Wilcoxon and Mann-Whitney tests. Results: Systolic and diastolic blood pressure were lower in the intervention control group before and after the intervention (p=0.015 and 0.018) with a difference (p=0.105) (p&gt;0.05) of -3 systole and -3.5 diastole. Mean analysis for the intervention and control groups in systolic blood pressure revealed a p-value of 0.628, signifying no significant difference between the groups (p&gt;0.05). While the control group's systolic and diastolic blood pressure before and after the intervention (p=0.007 and 0.003) (0.05) showed a difference (p=0.271) (p&gt;0.05) with a decrease in the control group's systole -8.39 and diastole -3.22, there was no statistically significant difference between the two intervention and control groups—only a decrease. Conclusion: Giving breadfruit leaf extract capsules to the intervention group with obese respondents and high blood pressure showed a decrease in blood pressure after giving breadfruit leaf extract capsules. People with high blood pressure can consume breadfruit leaf decoction or extract.

Study of the Effect of Multi-Walled Carbon Nanotubes on the Mechanical Properties of Poly(Vinyl Alcohol)/Polyaniline Blend Film

In this research, poly(vinyl alcohol)/polyaniline blend films were fabricated using solution casting technique with different weight ratios of PANI (2, 4, 6, 8, and 10) wt.%. The results showed that the best ratio of the polymer blend was (92% PVA/8% PANI), based on the electrical conductivity of direct current. The results showed that 8 wt.% PANI possessed the highest conductivity. Then, the composite films were prepared by adding multi-walled carbon nanotubes (MWCNT) to the optimum ratio of the polymer blend as a base material and at different weight ratios (0, 1, 3, 5, 7 wt.%). A tension device was used to examine and characterize the prepared samples. It was found that the addition of MWCNT to PVA/PANI caused an obvious decrease in elongation while there was an increase in tension strength and “Young’s modulus”. Optical microscopy results showed a good picture of the distribution of MWCNT particles for composites up to 1 wt.% MWCNT. But, some aggregations can be observed in films with 3, 5, and 7 wt.% MWCNT content.

Open Reduction of Pediatric Femur Fracture: A Technical Trick

Open Reduction of Pediatric Femur Fracture: A Technical Trick

Ultrasonic bone scalpel for long bone resections in limb reconstruction: Device description and case series

IntroductionWhile the ultrasonic bone scalpel (UBS) has shown benefits, including decreased surgical duration, blood loss, and local tissue thermal injury, its implementation has been limited to skull base and spinal surgery. This case series sought to determine the safety and advantages of the UBS for bony resections in limb reconstructive procedures. MethodsA retrospective review of four patients with a median age of 42 ± 13.38 at the time of resection and bone segment transport (BST) surgery was performed with UBS. Patients with prior history of lower extremity trauma with sequelae including non-union (2), osteomyelitis (1), or both (1). Intraoperative and post-operative courses and complications were documented. ResultsEach patient underwent tibial resection with UBS with a median bone resection size of 6.6 ± 2.85. Three patients underwent BST using cables and external fixator and one underwent plate-assisted BST with an intramedullary device. All patients had proximal corticotomies and antegrade transport, with a formal docking procedure at the end of transport. Complications included fixator cable tensioning device failure, frame readjustment, and pin tract infections. Two patients required subsequent grafting for docking site nonunion. One patient terminated bone transport early. No neurovascular injuries, hematomas, or dead space infections were reported. ConclusionThe UBS offers a safe mechanism for long bone resections in lower extremity limb reconstruction. Neurovascular structures within the resection zone were preserved and uninjured, demonstrating major advantages in using this technology. Further study is needed to assess the risk for docking site nonunion with UBS.

Manual and Device-Assisted Hamstring Autograft Tensioning Yield Similar Outcomes following ACL Reconstruction.

A prospective comparative study was conducted between September 2015 and May 2017. Sixty-four patients (mean age 29.3 years, range 14-45) with isolated ACL injuries (and who would be subjected to ACL reconstruction with a quadruple hamstring tendon graft) were divided into two groups. In Group A (n = 29), common tension was applied manually to both grafts. In Group B (n = 35), specific tension was applied to the grafts with the use of a tensioner device (ConMed Linvatec SE™ (Stress Equalization) Graft Tensioning System). A total of 60 N was applied to the semitendinosus, and 40 N was applied to the gracilis. Clinical outcomes were assessed at 6, 12, and 24 months. There were no significant differences between the baseline demographic and clinical data among the patients of the two groups (all p > 0.05). The patients were followed up for a minimum of 24 months (mean ± SD). There were no significant differences in the side-to-side anterior knee laxity, the IKDC, the Lysholm Knee, and the Tegner Activity Scale scores for up to 24 months after operation. The pivot shift test was negative in all cases, and no graft failure was reported at a 2-year follow-up. No significant differences were found with respect to postoperative anterior knee laxity, clinical outcomes, activity level, and patient satisfaction between the application of manual tension and the use of the graft-tensioning system during tibial fixation while performing anatomic single-bundle ACL reconstruction with a quadruple hamstring tendon graft. Further high-quality clinical studies are required to elucidate whether device-assisted tension is superior to manual tension.

Autonomous observations of biogenic N2 in the Eastern Tropical North Pacific using profiling floats equipped with gas tension devices

Oxygen Deficient Zones (ODZs) of the world’s oceans represent a relatively small fraction of the ocean by volume (&amp;lt;0.05% for suboxic and&amp;lt;5% for hypoxic) yet are receiving increased attention by experimentalists and modelers due to their importance in ocean nutrient cycling and predicted susceptibility to expansion and/or contraction forced by global warming. Conventional methods to study these biogeochemically important regions of the ocean have relied on well-developed but still relatively high cost and labor-intensive shipboard methods that include mass-spectrometric analysis of nitrogen-to-argon ratios (N2/Ar) and nutrient stoichiometry (relative abundance of nitrate, nitrite, and phosphate). Experimental studies of denitrification rates and processes typically involve either in-situ or in-vitro incubations using isotopically labeled nutrients. Over the last several years we have been developing a Gas Tension Device (GTD) to study ODZ denitrification including deployment in the largest ODZ, the Eastern Tropical North Pacific (ETNP). The GTD measures total dissolved gas pressure from which dissolved N2 concentration is calculated. Data from two cruises passing through the core of the ETNP near 17 °N in late 2020 and 2021 are presented, with additional comparisons at 12 °N for GTDs mounted on a rosette/CTD as well as modified profiling Argo-style floats. Gas tension was measured on the float with an accuracy of&amp;lt; 0.1% and relatively low precision (&amp;lt; 0.12%) when shallow (P&amp;lt; 200 dbar) and high precision (&amp;lt; 0.03%) when deep (P &amp;gt; 300 dbar). We discriminate biologically produced N2 (ie., denitrification) from N2 in excess of saturation due to physical processes (e.g., mixing) using a new tracer – ‘preformed excess-N2’. We used inert dissolved argon (Ar) to help test the assumption that preformed excess-N2 is indeed conservative. We used the shipboard measurements to quantify preformed excess-N2 by cross-calibrating the gas tension method to the nutrient-deficit method. At 17 °N preformed excess-N2 decreased from approximately 28 to 12 µmol/kg over σ0 = 24–27 kg/m3 with a resulting precision of ±1 µmol N2/kg; at 12 °N values were similar except in the potential density range of 25.7&amp;lt; σ0&amp;lt; 26.3 where they were lower by 1 µmol N2/kg due likely to being composed of different source waters. We then applied these results to gas tension and O2 (&amp;lt; 3 µmol O2/kg) profiles measured by the nearby float to obtain the first autonomous biogenic N2 profile in the open ocean with an RMSE of ± 0.78 µM N2, or ± 19%. We also assessed the potential of the method to measure denitrification rates directly from the accumulation of biogenic N2 during the float drifts between profiling. The results suggest biogenic N2 rates of ±20 nM N2/day could be detected over &amp;gt;16 days (positive rates would indicate denitrification processes whereas negative rates would indicate predominantly dilution by mixing). These new observations demonstrate the potential of the gas tension method to determine biogenic N2 accurately and precisely in future studies of ODZs.

STRUCTURE OF THE COMPUTER MODULE OF THE KDAM PROGRAM FOR DETERMINING KINEMATIC AND DYNAMIC PARAMETERS OF THE INPUT LINK

The development of the computer module of the KDAM program for determining the kinematic and dynamic parameters of the input link of the mechanisms of light industry machines allows to determine the coordinates, projections of speeds and accelerations of the center of mass of the crank and the point of attachment of the links of the Asura groups. During the dynamic analysis of the operation of the input link, the projections of the full reaction in the hinge of the input link are determined. The obtained results are used in the program to assess the intensity of technological processes of the light and textile industry when determining the change in the relative tension of the thread in the filling zones on the technological equipment. Lever mechanisms are widely used in light and textile industry machines. The working bodies of the lever mechanisms come into contact with the threads during operation. Depending on the trajectory of the movement, the angle of coverage of the working bodies of the mechanisms of the light and textile industry machines changes. A change in the value of the angle of coverage leads to a change in the tension of the threads. When the coverage angle increases to critical values, the thread may break and the technological equipment may stop. The tension of the thread increases when moving through the refueling zones of the thread feeding system on the technological equipment. This increase is due to the interaction of the thread with the guides and tension devices. The maximum tension value will be in front of the working area. A sharp increase in tension leads to a violation of the normal course of the technological process of thread processing. The development of new schemes of the thread feeding system requires an operational assessment of the value of the tension in front of the working zone. The development of special computer programs for determining the tension in the working area makes it possible to determine the necessary technological parameters. The objective function in the tasks of optimization of technological processes is the minimum necessary tension. The variable parameter in the objective function is the sum of the angles of coverage of the working bodies by the thread. The use of a computer program allows you to determine the tension and change in relative tension in the filling zones of technological machines, which allows you to optimize the shape of the thread supply line even at the stage of designing the technological process. Computer determination of kinematic and dynamic parameters of flat mechanisms allows to determine the parameters used in determining the intensity of technological processes. The study of the influence of the design of the thread tension device on the conditions of its interaction with the thread, taking into account its unevenness in the diameter of the cross section, is important in determining the thread tension. The tension of the thread increases when moving through the refueling zones of the thread feeding system on the technological equipment.

An electronic force sensor accurately detects increased but not decreased soft tissue tension in total knee arthroplasty

BackgroundPostoperative knee instability is a leading cause of revision total knee arthroplasty (TKA). This study used a commercially available insert-shaped electronic force sensor to measure joint loads and facilitate ligament balance adjustment, and assessed the ability of this sensor to detect increased or decreased soft tissue tension during primary TKA. MethodsChanges in medial and lateral tibiofemoral joint loads during knee flexion were evaluated with sensor thicknesses ranging from 10 to 16 mm using six varus osteoarthritis cadaver knees with intact medial collateral ligaments (MCLs), and the measurements were repeated after MCL resection. Correlations between joint loads and maximum knee extension angle were also evaluated. To validate the efficacy of the sensor, the values were compared with those obtained using a conventional tension device. ResultsFor MCL-intact knees in extension, the medial joint load increased with sensor thickness. The maximum knee extension angle decreased with sensor thickness (ρ = −0.4), resulting in extension restriction up to −20°. Knee flexion contracture was below 5° when the total tibiofemoral joint load was below a cut-off of 42 lb. After the MCL was resected, medial joint loads remained unchanged at low values, even with increased sensor thickness. In contrast, the tension device clearly detected an increased gap as the degree of tension decreased. ConclusionsThe electronic sensor identified increased joint loads associated with increased ligament tension, and could predict knee flexion contracture during TKA. However, unlike the tension device, it did not accurately detect excessively decreased ligament tension.

DEVELOPMENT OF A COMPUTER MODULE FOR KINEMATIC AND DYNAMIC ANALYSIS OF IMPORTANT MECHANISMS OF LIGHT INDUSTRIAL MACHINES, PROGRAMS FOR ASSESSING THE TENSION OF TECHNOLOGICAL PROCESSES

The development of a computer module for kinematic and dynamic analysis of the lever mechanisms of light industry machines allows determining the parameters that are used in the program to assess the intensity of technological processes of the light and textile industry when determining the change in the relative tension of the thread in the filling zones of the technological equipment. Kinematic and dynamic analysis of flat mechanisms plays a significant role in the design of new mechanisms and modernization of existing ones. The results obtained during these studies can be used to calculate the strength of individual links, their inertial characteristics, optimization of structural parameters of mechanisms, and minimization of consumed energy. A sharp increase in tension leads to a violation of the normal course of the technological process of thread processing. The imperfection of the structural elements of the feed system, thread tensioning devices and thread guides on knitting, textile and sewing machines will not allow thread processing with a sudden increase in input tension. The development of new schemes of the thread feeding system requires an operational assessment of the value of the tension in front of the working zone. To do this, it is effective to use specially developed programs for performing a computational experiment. The tension of the thread increases when moving through the refueling zones of the thread feeding system on the technological equipment. This increase is due to the interaction of the thread with the guides and tension devices. The maximum tension value will be in front of the working area. The development of special computer programs for determining the tension in the working area allows you to determine the necessary technological parameters, make adjustments to both the structure itself and the components of the thread feeding system to obtain the minimum necessary tension in the working area. The objective function in the problem is the minimum necessary tension, which is the minimum sum of the angles covered by the thread of guide surfaces that have a cylindrical, elliptical shape, discrete segments of a straight line. The use of a computer program allows you to determine tensions and changes in relative tension in the filling zones of light and textile industry machines, which allows you to optimize the shape of the thread supply line even at the stage of designing the technological process. The development of application packages of computer programs allows to reduce the time for the design of technological processes in the light and textile industry as much as possible. This is due to the modernization of the thread filling line on the technological equipment, which allows to minimize thread tension in the working area. Minimization of tension is ensured by optimization of the shape of the thread filling line, in which the total angle of coverage of the guides will be minimal. Computer determination of kinematic and dynamic parameters of flat mechanisms allows to determine the parameters used in determining the intensity of technological processes.

Justification of the parameters of the effective design of the centering tension roller of the conveyor belt

The article provides a structural diagram and principles of operation of the centering tensioning device of the belt conveyor. Based on theoretical research, the parameters of the centering device of the belt conveyor have been substantiated. Production tests substantiated the technical and economic indicators of the belt conveyor with the recommended centering tensioner.

Автоколебания клетей стана тандема холодной прокатки 2000 Магнитогорского металлургического комбината

One of the problems of cold rolling of thin strips is self-excited chatter vibrations, which lead to the appearance of various defects. High-frequency self-oscillations can lead to defects related to surface quality, low-frequency ones with high amplitude levels can lead to gusts of thin bands or even severe accidents of the rolling mill itself. As a rule, self–oscillations occur suddenly at high rolling speeds, more than 20 m / s and thin strips, the thickness is usually around 300-700 microns. For the normal operation of the rolling mill, it is necessary to use special systems for monitoring the vibration state and preventing the occurrence of self-oscillations. The control system for exceeding the critical vibration level generates signals from the automated control system of the mill to eliminate self-oscillations. The critical vibration level is determined by the spectral composition using the fast Fourier transform (FFT). When self-oscillations occur, lowfrequency components from 5 to 20 Hz prevail, frequencies in the range of the third octave from 100 to 200 Hz and frequencies of the fifth octave from 400 to 800 Hz. The cold rolling mill 2000 of the Magnitogorsk Iron and Steel Works combines a tandem five-cell mill and a continuous etching unit. There is no regular vibration monitoring system at the mill, warning and elimination of self-oscillations occurs in manual mode. With the use of research vibration equipment, experimental studies have been conducted on the possibility of using technological parameters to control and prevent the occurrence of self-oscillations. The moment of occurrence of self-oscillations can be controlled by the vibrations of the hydraulic tensioning device (GNU) of the mill. Processing of the vibration displacement signal of the measuring channel of the GNU FFT

Research on Improvement of Synchronous Tensioning Device of Belt Conveyor

Under complex working conditions in the mines, the belt conveyor’s tensioning device is prone to uneven tension. Given this problem, the error of the shunt of synchronous motors is analyzed, and a synchronous tensioning device with double cylinders is designed by using a synchronous motor and a PID controller. Simulation analysis is carried out to verify the rationality and effectiveness of the optimization design. It can provide a corresponding reference for the design and use of the belt conveyor synchronous tensioner system.

High-resolution biological net community production in the Pacific-influenced Arctic as constrained by O2/Ar and O2/N2 observations

Spatial and temporal patterns of primary productivity in the Arctic are expected to change with warming-associated changes in ice cover and stratification, yet productivity measurements are historically spatially and temporally limited. Over the last two decades, an approach that uses measurement of dissolved oxygen/argon ratios (O2/Ar) from a vessel's underway seawater system has emerged as an established method to assess net community production (NCP) rates with high spatial and/or temporal resolution. More recently, the measurement of oxygen/nitrogen ratios (O2/N2) with a gas tension device (GTD) and optode have been piloted in underway settings to provide comparable NCP estimates. The GTD/optode approach has several advantages: instrumentation is small, inexpensive, and suitable for autonomous deployments; however, dissimilarity in solubility between O2 and N2 makes this tracer pair less accurate than O2/Ar. We conducted a side-by-side ship-based comparison of a GTD/optode and Equilibrator Inlet Mass Spectrometer (EIMS) in the Pacific Arctic during one of the North Pacific Research Board Integrated Ecosystem Research Program cruises in 2019. NCP from O2/Ar and O2/N2 approaches were coherent throughout this cruise, with median mixed layer integrated NCP of 9.3 ± 2.8 and 7.9 ± 3.2 mmol O2 m−2 day−1, respectively. The range of NCP was large, from less than zero to >100 mmol O2 m−2 day−1, with some of the largest NCP estimates measured at well-established hotspots in the Pacific Arctic. While O2/Ar and O2/N2 largely tracked each other, deviations were observed, principally in the Bering Sea where wind-induced bubbles were a primary driver, while a combination of temperature and wind drove differences over the majority of the cruise. The GTD/optode can be used to enhance spatial and temporal coverage of NCP measurements, yet the uncertainty makes this approach better-suited to regions with higher overall rates of NCP, while regions near-equilibrium may result in unacceptably high uncertainty. Additionally, the GTD/optode is reliant on well-calibrated oxygen observations, a potential challenge if autonomously deployed.

Intrascleral anchoring knot on the double suture without peritomy for fixation of intraocular lens.

A new minimally invasive technique for universal fixation of any posterior chamber intraocular lens (IOL), iris prosthesis or capsular tension device (CTD), both for rescuing in case of dislocation and for secondary implantation, is described. It uses intrascleral anchoring knot on the reinforced double 9-0 polypropylene suture without conjunctival opening or scleral dissection. The technique was applied for scleral fixation of the S-shaped monoblock acrylic IOL dislocated into the vitreous cavity in 1 eye, and decentered IOL-CTD-capsular bag complexes in 3 eyes. In none of the cases, complications including knot slippage, suture exposure or hypotony were observed. All patients were followed up for 6 months. The uncorrected distance visual acuity was significantly improved and the IOLs positions remained stable. The described technique might be a simple, effective and safe alternative to flanged scleral fixation approaches.

Investigation of acoustic softening and microstructure evolution characteristics of Ti3Al intermetallics undergoing ultrasonic vibration-assisted tension

Ultrasonic vibration-assisted deformation (UVAD) technology has been widely utilized in the metallic materials forming and manufacturing process owing to its advantages of effectively reducing deformation stress. However, the intrinsic mechanism of UVAD involved in Ti3Al intermetallics has not yet been clarified. In this research, an ultrasonic vibration tension device for Ti3Al was designed. The mechanical properties under ultrasonic vibration-assisted tension (UVAT) were investigated. Subsequently, the rheological behavior under the effect of ultrasound was analyzed. The influences of the vibration amplitudes and vibration modes on the microhardness and microstructure were explored. The results indicated that Ti3Al behaved obviously an acoustic softening after introducing ultrasonic energy, and the degree of softening was positively correlated with amplitude. There was a “competitive” relationship between the acoustic softening and acoustic residual hardening effects. The maximum stress and microhardness reductions were 206.13 MPa and 6 % when the amplitude was 6.55 μm and 1.31 μm, respectively. The fracture mode evolved from ductility dimple fracture to a mixed-mode of cleavage pattern and brittle fracture. The metallographic organization revealed a “defective phase” structure in the α2 phase and B2 matrix. The amounts of defective phases enlarged with amplitude increasing and extended away from the vicinities of the fracture cross-section.

Experience using a flexible reinforced fiber suture for sternal closure in bilateral lung transplantation recipients undergoing bilateral transverse thoracosternotomy.

Experience using a flexible reinforced fiber suture for sternal closure in bilateral lung transplantation recipients undergoing bilateral transverse thoracosternotomy.

Mechanical performance evolution and life prediction of prestressed CFRP plate exposed to hygrothermal and freeze-thaw environments

The long-term prestressed loss of anchorage system and mechanical property evolution play the significant role for the steel/concrete structures strengthened with prestressed CFRP plates. In the present study, a wedge-extrusion bond anchorage system was applied to provide the reliable anchorage load-bearing capacity for CFRP plate. A new prestressed tension device was put forward to realize the coupling exposure of elevated temperature (20 °C, 60 °C and −20 to 30 °C), distilled water and sustained loading (20%, 40% and 60%). The mechanical and thermal properties of CFRP plate were conducted to obtain the long-term evolution exposed to the above environments. The mechanical analysis and tensile tests of anchorage system showed the tensile failure modes under the static and cyclic loads were the CFRP burst, and there was no debonding occurring in the anchor. The higher anchorage capacity was attributed to the uniform stress distribution of CFRP plate parallel to the greatest dimension of cross section in the anchor. The new prestressed tension device can realize the maximum prestressed level (∼70%) with an allowable prestressed loss (∼300 με). Meanwhile, the prestressed loss of CFRP plate exposed at the maximum temperature (60 °C) and longest time (90 days) was found to be ∼300 με. Immersed at higher temperature and prestressed level brought about an additional degradation rate of tensile strength (5%∼10%). The minimum strength retention of CFRP plate was found at the freeze-thaw exposure for 90 days. The long-term life prediction showed the residual tensile strength retentions of CFRP plates were more than 50% for the maximum prestressed level (60%) for the service life of 30 years in civil engineering structures.