Support Plate Research Articles

Characteristics of Laminar Separation Bubble With Varying Leading-Edge Shapes and Deflections of the Trailing-Edge Flap

Abstract A series of implicit large eddy simulations (ILES) is carried out to examine the characteristics of a leading edge (LE) separation bubble. The test case comprises a flat plate with an elliptic leading edge (ELE), which is equipped with a trailing edge flap. Simulations are carried out (a) at three different flap angles (20 deg, 30 deg, 90 deg) and (b) using two different geometries of ELE where the ratio of the semimajor to semiminor axis is set to either 2:1 or 4:1. The flap is modeled using the immersed boundary method, which is computationally economical as it avoids regenerating the grid for varying flap angles. The results show that (a) the flow separates at lower flap deflection angles with a decrease in the aspect ratio of the ELE from 4:1 to 2:1 (b) an increase in the flap angle promotes separation at the LE due to an increase in the blockage in the bottom passage and a subsequent increase in the flow incidence at the leading edge. Simulations are also carried out using the γ−Reθ transition model and comparisons are drawn against ILES and experiments. Although the qualitative trends predicted using both ILES and Reynolds-Averaged Navier–Stokes (RANS) agree with the experiments, both approaches predict relatively shorter separation bubbles. This is attributed to the excess flow blockage in experiments due to the support plates, which are not modeled in the simulations. Nevertheless, the results demonstrate the superior accuracy of ILES over the RANS model.

Secondary flexural behaviour of reinforced concrete beams strengthened with special-shaped rivet bonded steel plates and prestressed CFRP bars

Special-shaped rivet and glued steel plate reinforcement is an innovative structural reinforcement technology. A riveted glued steel plate primarily relies on the rivet to transfer shear. Prestressed carbon fibre-reinforced polymer (CFRP) reinforcement is a new technique for strengthening concrete structures. These studies focus on the ‘primary load’, overestimate the ultimate flexural load of the components by neglecting the ‘secondary load’ of the components in real engineering. In this study, the flexural properties of concrete beams strengthened using special-shaped rivet steel plates and CFRP prestressed bars were studied theoretically and experimentally. The cracking load, ultimate load capacity, and strain of the steel plate, steel bar and CFRP bars were recorded during the tests. In addition, the failure mode of the beams was observed, and the effect of secondary stress on the flexural capacity of the beams was analysed. The failure load of the beams strengthened by CFRP prestressed tendons increased by 67.8% and 46.1% for beams with primary and active secondary loads, respectively. The failure load of the special-shaped rivet and glued steel plate strengthened beam increased by 115.7% and 160.5%, for beams with primary and active secondary loads, respectively. Both methods have a strong guiding significance for engineering practice.

Outcomes of Anterior Lateral Approach and Gerdy's Tubercle Osteotomy for Tibial Plateau Fractures Involving the Posterior Lateral Condyle: A Retrospective Study of 20 Patients.

BACKGROUND The objective of this investigation was to assess the effectiveness of using T-shaped steel plates through the anterior lateral approach and Gerdy's tubercle osteotomy for treating posterior lateral tibial plateau fractures. MATERIAL AND METHODS A retrospective analysis was conducted on clinical data from 20 patients, aged on average 53.9±10.36 years, who were admitted for tibial plateau fractures involving the posterior lateral condyle between January 2019 and October 2022. The fixation and reduction of the posterior lateral bone block were performed using the anterior lateral approach combined with Gerdy's tubercle osteotomy to address the posterior lateral tibial plateau fracture. Post-surgery assessment was conducted using the Hospital for Special Surgery (HSS) knee combined score. RESULTS During the 12-24 (14.2±1.7) month postoperative period, we conducted 20 surgeries. Within 9 to 12 weeks, fracture healing transpired without any complications such as incision infection, nerve injury, or fracture displacement being detected. Assessment of knee joint function at the final follow-up was conducted using the HSS knee combined score, with results indicating 16 cases rated as excellent, 3 cases as good, and 1 case as fair. CONCLUSIONS In tibial plateau fractures impacting the posterior lateral condyle, the anterior lateral approach, combined with Gerdy's tubercle osteotomy, allows for direct exposure and manipulation of the posterior lateral bone block fracture. Using a T-shaped support plate and a lateral locking plate provides a reliable method for fracture fixation, aiding in convenient surgical positioning and intraoperative fluoroscopy. The treatment approach effectively manages fractures located on the posterior lateral aspect of the tibial plateau.

Resilience-based seismic design and cyclic behavior of assembled joints between self-compacting concrete-filled rectangular steel tube frame columns and H-shaped steel beams

The overall stability of prefabricated steel structures depends significantly on the strong seismic resilience exhibited by the connections between beams and columns. This paper introduces a novel beam–column connection approach, referred to as the welded upper and lower flanges and two diagonal web plates (WULF-TDWP). Unlike conventional methods, this approach replaces bolted connections with butt-welded joints between steel beams and employs short cantilever beams to achieve plastic hinge displacement. The steel-column cross-section was designed with a larger aspect ratio to better absorb and distribute energy. Six full-scale specimens were subjected to cyclic loading tests to investigate the seismic performance of the WULF-TDWP system. The main test parameters included the axial load ratio, welding configuration in the node region, and presence of reinforcement plates. The specimens exhibited two distinct failure modes: plate buckling deformation and beam–column end weld tearing. The experimental results included the hysteresis curves, skeleton curves, ductility coefficients, stiffness degradation curves, and strength degradation curves of the specimens. The experimental findings highlighted the favorable hysteresis performance, load-carrying capacity, and deformation capacity of all the nodes. Additionally, the plastic hinges were observed to shift, thereby delaying the premature failure of the node region. Notably, the omission of welding between the cantilever short beam flange and steel column significantly reduced the initial stiffness of the node. Through finite element analysis, the seismic performance of the beam-column joints with upper and lower flange welded connections and cantilever short beams was elucidated. The reliability of the finite element model for assessing the seismic performance of the nodes was confirmed through validation using experimental findings. Furthermore, this paper categorizes the nodes and introduces a simplified calculation model based on the moment–rotation method.

Increasing the Punching Shear Capacity of Flat Plate Reinforced Concrete Utilizing CFRP Warp and Bar

Increasing the Punching Shear Capacity of Flat Plate Reinforced Concrete Utilizing CFRP Warp and Bar

Computational evaluation of the bucky components influence on the estimation of normalized glandular dose in digital mammography

The mean glandular dose (MGD) is the most suitable dosimetric quantity used in mammography to describe the absorbed dose by the breast, although it cannot be directly acquired. Studies have provided conversion factors widely implemented in international dosimetry protocols to estimate MGD, such as normalized glandular dose (DgN). Over time, the DgN estimation was refined by considering geometric models that approach a real clinical environment, such as new anode/filter combinations, compression plate and breast models. However, there is no detailed study of how the bucky (support plate, antiscatter grid and detector) can affect the DgN estimation. A modified PENELOPE Monte Carlo code was used for DgN estimation. The irradiation geometric model was built as a complete digital mammography system, considering a homogeneous breast and different typical bucky models in commercial mammography units. Simulations were carried out for mono and polyenergetic beams considering different imaging geometries. Studies with monoenergetic beams showed that the bucky presence affected DgN mainly for higher beam energies and thinner breasts. The breast support plate was the bucky component that most affected the DgN, followed by the antis-scatter grid and finally, the image detector. Studies with polyenergetic conventional (low-energy) spectra showed that the bucky exerted a minimal influence on DgN values (less than 1.0%). For high-energy spectra, mainly employed in modalities such as contrast-enhanced digital mammography, the DgN values were more affected by the bucky, increasing by 4.8% the DgN values for a 2 cm thick breast and a W/Cu 50 kV spectrum. Bucky inclusion in computer simulations is highly recommended mainly for thinner breasts and high-energy spectra. To simplify the simulations, we confirm that a homogeneous carbon fibre block support, with thickness between 3.9 and 4.1 mm, can be used as a good substitute for a complete bucky model.

Structural Optimization of 60T Electric Mining Vehicle Frame: Finite Element Simulation Model and Analysis

Based on the research under the ore loading condition of the electric mine vehicle, this paper measures the physical frame of the 60T electric mine vehicle by means of rangefinder, ruler and drawings, and uses the software CATIA to complete the three-dimensional model of the frame and carriage of the electric mine vehicle, combined with the characteristics of ANSYS workbench software. The structure of the model is simplified. By comprehensively applying relevant knowledge of automobile dynamics, the frame load under full load condition is calculated, and the electric mine vehicle frame is applied by using ANSYS workbench software to simulate and optimize the three conditions of stationary, high-speed driving and turning before the mine car, and the position where the stress concentration and deformation of the frame structure are greatest. By increasing the thickness of the support plate and increasing its stress area, the overall weight was increased by 90.35kg, accounting for 0.9% of the total weight, and the weight increase was very small. Mechanical analysis was carried out on the three working conditions of the optimized frame of the mine car, and the stress was reduced by 25%, 24.1% and 39.2% respectively, effectively eliminating the stress concentration. The actual use of the vehicle can extend the service life of the frame, while improving the economy and stability of the vehicle.

Compression after impact (CAI) failure mechanisms and damage evolution in large composite laminates: High-fidelity simulation and experimental study

This study focuses on developing and validating a high-fidelity finite element model for predicting damage evolution and residual strength in fiber-reinforced composite panels. Impact and compression after impact (CAI) tests were conducted at both barely visible impact damage (BVID) and clearly visible impact damage (CVID) levels. The ASTM D7137 standard 100 mm × 150 mm CAI coupons were inadequate to cover the range of experimental studies required for model validation. Therefore, larger 254 mm × 304.8 mm laminates were investigated under two CAI testing conditions: one a scaled-up version of ASTM standard coupon, and the other with additional anti-buckling support plates to reduce unsupported areas to 127 mm × 177.8 mm. The model captured inter- and intra-laminar failure modes, including fiber breakage, splitting, kinking, pull-out, and crushing as well as matrix cracking, delamination, and their interactions. This was achieved by cohesive zone modeling technique and enhancement of the LaRC05 failure criteria through modeling the fiber damage evolution and utilizing an efficient search algorithm to determine the matrix fracture plane and fiber kink band angle. This study underscores the efficacy of the high-fidelity modeling approach in accurately predicting both impact damage and CAI strength in typical aircraft impact damage scenarios. Additionally, it provides insights into complex CAI failure mechanisms and energy release associated with various damage modes and highlights the effect of global buckling on the failure behavior and compressive strength of composite laminates. Furthermore, it shows that the proposed fixture with support plates is suitable for testing a broader range of impact scenarios without experiencing global buckling.

Comparison of effectiveness of three surgical methods in treatment of Pauwels type Ⅲ femoral neck fracture in young and middle-aged patients

To compare the effectiveness of three surgical methods in the treatment of Pauwels type Ⅲ femoral neck fracture in young and middle-aged patients, in order to provide reference for clinical selection of appropriate surgical methods. The clinical data of 103 patients with Pauwels type Ⅲ femoral neck fracture who met the selection criteria between June 2018 and December 2021 were retrospectively analyzed. The fractures were fixed with hollow screws in an inverted triangular shape (37 cases, hollow screw group), hollow screws in an inverted triangular shape combined with eccentric shaft screw (34 cases, eccentric shaft screw group), and hollow screws in an inverted triangular shape combined with medial support plate (32 cases, support plate group). There was no significant difference in age, gender, cause of injury, body mass index, time from injury to operation, side of the fracture, and Garden classification, whether they were in traction preoperatively, and other baseline data between groups ( P>0.05). The operation time, intraoperative blood loss, the number of fluoroscopy, the length of hospital stay, early postoperative complication and postoperative weight-bearing time of the three groups were recorded. Harris score was used to evaluate joint function at 6 and 12 months after operation, and the difference between the two time points (change value) was calculated for comparison between groups. X-ray films were reviewed to evaluate the quality of fracture reduction (Garden index) and healing, as well as the occurrence of internal fixation failure and femoral head necrosis. The patients of the three groups were successfully completed. Compared with the hollow screw group and the eccentric shaft screw group, the operation time and intraoperative blood loss of the support plate group significantly increased, the number of fluoroscopy reduced, and the quality of fracture reduction was better, the differences were significant ( P<0.05). The operation time, intraoperative blood loss, and the number of fluoroscopy of the hollow screw group were less than those of the eccentric shaft screw group, the differences were significant ( P<0.05). There was no significant difference in the length of hospital stay between groups ( P>0.05). All patients in the three groups were followed up 21-52 months, with an average follow-up time of 36.0 months, and there was no significant difference between groups ( P>0.05). The incisions of all patients healed by first intention. Imaging reexamination showed that there was no significant difference in the incidence of fracture nonunion between groups ( P>0.05). The fracture healing, partial weight-bearing, and full weight-bearing were significantly earlier in the eccentric shaft screw group and the support plate group than in the hollow screw group ( P<0.05). There was no significant difference in change value of Harris score, the incidence of postoperative deep venous thrombosis and femoral head necrosis between groups ( P>0.05); however, the incidence of internal fixation failure in the support plate group and the eccentric shaft screw group was significantly lower than that in the hollow screw group ( P<0.05). The incidence of postoperative lateral thigh irritation in the support plate group was significantly lower than that in the hollow screw group ( P<0.05); there was no significant difference between the eccentric shaft screw group and the other two groups ( P>0.05). The overall incidences of postoperative complications in the eccentric shaft screw group and the support plate group were significantly lower than that in the hollow screw group ( P<0.05). For young and middle-aged patients with Pauwels type Ⅲ femoral neck fracture, compared with simple hollow screw fixation in an inverted triangular shape, combined with medial support plate or eccentric shaft screw internal fixation can shorten the fracture healing time, reduce the incidences of postoperative complication, more conducive to early functional exercise of the affected limb; at the same time, the operation time and blood loss of combined eccentric shaft screw internal fixation are less than those of combined medial support plate internal fixation, so the hollow screw in an inverted triangular shape combined with eccentric shaft screw fixation may be a better choice.

Experimental Study on Repairing/Restoration and Reinforcement Methods of the Reinforced Concrete Structures Damaged by Earthquakes

For earthquake-damaged reinforced concrete structures, the static loading test method is adopted to carry out loading tests under cyclic loading on reinforced concrete beams with different reinforcement rates and columns with different axial compression ratios, and the effect of reinforcing and repairing the damaged reinforced concrete structure by using adhesive steel plates and carbon fiber cloth is investigated. Through comparative studies of structural hysteresis curves and skeleton curves under different reinforcement methods, it is concluded that reinforcement has significantly improved the hysteresis characteristics and ductility of members, and the seismic performance of the carbon fiber reinforcement method is better than that of the steel plate reinforcement. This study provides valuable references and suggestions for practical earthquake-damaged building reinforcement and repair works and seismic reinforcement works.

A multiscale scheme for homogenization to characterize the flexural performances of injection molded short glass fiber reinforced polyether ether ketone composites

AbstractThe characterization of the flexural performances of short glass fiber reinforced polyether‐ether‐ketone (SGFR‐PEEK) composites fabricated by injection molding is a crucial and challenging task due to the process‐induced fiber orientation at different locations, resulting layered shell‐core‐shell microstructures and exhibiting large variations in mechanical performances. This article proposes a method for predicting the bending performance of SGFR‐PEEK and indicates the influence of fiber orientation on its bending behavior. This article reports a new scheme that combines multiscale homogenization with periodic microstructures and presents an experimental investigation of the flexural properties of SGFR‐PEEK composites. The distributions of fiber orientation through the thickness extracted from the micro‐computed tomography (μCT) were analyzed and reproduced with a layered skin‐shell‐core structure along the thickness at meso‐scale finite element model within representative volume elements (RVEs) of the macroscopic composites. Then, the effective properties of the RVEs were predicted using the homogenization method with the periodic boundary condition. The elastic modulus of skin‐shell‐core layers in the direction of flow are 4260.51, 4541.27, 4628.52, and 4630.84 MPa, respectively. The classical laminate theory (CLT) and the second homogenization implementation were then utilized in conjunction with the obtained mechanical properties of RVEs to predict the effective macrostructural behavior. The flexural modulus of the composite material was determined to be 5448.7 MPa through a three‐point bending test. The results obtained through lamination plate reinforcement theory and finite element simulation were 5887.4 and 5785.9 MPa, respectively, showing good agreement with the experimental findings. It is shown that the proposed multiscale scheme yields satisfactory agreement with experimental measurements. In addition, the effect of layered skin‐shell‐core microstructures on the flexural behavior was discussed.Highlights RVEs of layered shell‐core‐shell microstructures were generated with specified fiber orientations. The homogenization scheme with the periodic boundary condition was adopted to accurately predict each layer mechanical properties. The proposed multiscale scheme was compared with experimental results and yielded satisfactory predictions. The effect of layered skin‐shell‐core microstructures on the flexural behavior was thoroughly studied by the multiscale analytical approach.

Analisys of Tensile Strength, Wear Rate, and Cristallinity of Biocomposite Nano-HA/Magnesium/Shellac Reinforced Cantula Fiber for Bone Screw Material

Accidents are a major cause of fractures in Indonesia. One of the treatments for fractures is bone screws with support plates that are placed on broken bone. Currently, many biomaterials for bone screws are being developed which have biodegradable properties so that post-operative bone healing is not required. The purpose of this study was to determine the effect of cantula fiber addition on tensile strength, wear rate, and crystallinity of nano-HA/magnesium/shellac bio-composite for bone screw materials. Nano-HA/magnesium/shellac/cantula fiber materials were mixed using a blender. The material was mixed with a magnesium/hydroxyapatite ratio of 70/30 and cantula fiber was added with variations of 0%, 10%, 20% and 30% of total volume. After that, material mixture was compacted with a pressure of 300 MPa for 10 minutes. Then sintering process was carried out at temperature of 140 °C for two hours. The results showed that the highest tensile strength value was 7.86 MPa at 30% variation. The lowest wear rate was 0.31 x 10&lt;sup&gt;-3&lt;/sup&gt; mm&lt;sup&gt;3&lt;/sup&gt;/Nm at 30% variation. The highest crystallinity in X-Ray Diffraction observations was obtained at 30% variation, which was 79.65%.

Analytical Solution for the Ultimate Compression Capacity of Unbonded Steel-Mesh-Reinforced Rubber Bearings

Unbonded steel-mesh-reinforced rubber bearings (USRBs) have been proposed as an alternative isolation bearing for small-to-medium-span highway bridges. It replaces the steel plate reinforcement of common unbonded laminated rubber bearings (ULNR) with special steel wire meshes, resulting in improved lateral properties and seismic performance. However, the impact of this novel steel wire mesh reinforcement on the ultimate compression capacity of USRB has not been studied. To this end, theoretical and experimental analysis of the ultimate compression capacity of USRBs were carried out. The closed-form analytical solution of the ultimate compression capacity of USRBs was derived from a simplified USRB model employing elasticity theory. A parametric study was conducted considering the geometric and material properties. Ultimate compression tests were conducted on 19 USRB specimens to further calibrate the analytical solution, considering the influence of the number of reinforcement layers. An efficient solution for USRBs’ ultimate compression capacity was obtained via multilinear regression of the calibrated analytical results. The efficient solution can simplify the estimation of USRBs’ ultimate compression capacity while maintaining the same accuracy as the calibrated solution. Based on the efficient solution, the design process of a USRB with a specific ultimate compression capacity was illustrated.

Stress Analysis of Semi-covered Excavation Foundation Pit in Metro Stations based on Incremental Method

The station foundation pit of Ningbo Metro Line 2 is taken as engineering background, the support structure form of the semi covered excavation foundation pit is introduced. The standard section of the foundation pit is considered as a plane strain problem, a force calculation and analysis model for the half cover system structure is established based on the incremental method, concentrated load of a waste truck is applied within 5.0 m cover plate range outside the middle column and an impact coefficient of 0.4 is considered, overload with value of 20kPa is applied to the rest parts of the cover plate and 5.0 m outside the diaphragm wall. The excavation of the foundation pit is divided into 5 stages, the surface overload, structural self weight, soil pressure and elastic resistance increment, and support axial force are applied respectively, and the bending moment increment of the connecting wall and cover plate system at each excavation stage are calculated. The bearing capacities of the diaphragm wall and cover plate reinforcement are respectively calculated based on the rectangular bending normal section components, and they both meet the strength requirements.

STRESSES IN COMPOSITE PLATES WITH RIVETED BARS USED FOR AIRCRAFT CONSTRUCTION

Reinforcement of plates with rod systems is widely used in engineering, especially in aircraft construction. For example, An-178 aircraft. Removable panels on the lower surface of the wing half, located between the rear spar and the flaps. The method of calculating stresses and deformations in composite plates reinforced with rods is developed in the work. It is assumed that the rod is elastic, attached with rivets. Rivets were considered as rigid inclusions to which unknown forces were applied. These forces were determined from the condition of compatibility of plate and rod deformations. The singular integral equations' method was used to determine stresses and strains in the plate. Integral equations were solved numerically and reduced to a system of algebraic equations. To obtain the forces and moments acting on the rivets, the equations of equilibrium of the rivets and the conditions that ensure the same displacements between the rivets in the plate and in the rods are added to these equations. Examples of calculating stresses near circular and elliptical rivets, magnitudes of forces acting on rivets depending on the rigidity of the rods are given. The reduction of the stress concentration near the elliptical hole, which is placed between two rods, was studied.

Application of Intramedullary Calcar Support Plate and Lateral Locking Plate in Elderly Patients with Neer 3 and 4-Part Fractures of Proximal Humerus Through a Deltoid Splitting Approach

BackgroundThe reduction and fixation of Medial humeral calcar is difficult in the treatment of elderly proximal humerus Neer 3 and 4-part fractures with a single lateral locking plate. Our study investigated the efficacy of an intramedullary calcar supporting plate combined with a lateral locking plate for the treatment of 3- and 4-part fractures of the proximal humerus in the elderly through a deltoid splitting approach.MethodsFrom June 2022 to December 2022, we treated six elderly patients with Neer 3 and 4-part fractures using proximal humeral intramedullary calcar support plate in combination with lateral locking plate through a deltoid splitting approach. Follow-up time was 6–12 months. Assessment indicators included fracture union, quality of reduction, and complication rate. The Constant-Murley score was used to record shoulder function at 6 months postoperatively.ResultsAll 6 patients showed fracture union and anatomic reduction. Constant-Murley score was 79.5 (70–90) at 6 months postoperatively. There was no incision non-healing, internal fixation failure, bone non-union or surgical site infection, secondary surgery, or death. Shoulder impingement occurred in 1 case.ConclusionProximal humeral intramedullary calcar support plate combined with lateral locking plate fixation through a deltoid splitting approach can effectively maintain fracture reduction, prevent inversion collapse of humeral head and internal fixation failure, and provide satisfactory clinical results at an early stage.

Experimental study of turbulent flow in lower plenum with flow skirt of reactor pressure vessel of pressurized water reactor

The turbulent flow in lower plenum of reactor pressure vessel (RPV) of pressurized water reactor (PWR) is an important phenomenon for design of flow mixing device. A high-precision matched index of refraction (MIR) technique is requisite for time-resolved particle image velocimetry (TR-PIV) measurements in RPV with complicated internals. In this study, turbulent flow in a scaled-down RPV model was measured by TR-PIV under different Reynolds numbers (Re) and asymmetrical flow rate with aid of the high-precision MIR technique of sodium iodide (NaI) solution and acrylic. The time-averaged flow structures include flow separation at the corner of lower support plate, fluid bifurcation around the lower edge of flow skirt, flow turning upward below the vortex suppression plate, horizontal jets at holes of flow skirt, vertical jets at holes of vortex suppression plate, improving turbulent mixing and Reynolds stresses in the lower plenum. The coherent structures were studied by proper orthogonal decomposition (POD) analysis. The flow skirt and vortex suppression plate break down large vortices through them. With Re increasing, Reynolds stresses decrease fast, and the energy fractions of low-order modes transfer into high-order modes, because turbulent vortices break up. In the case of asymmetrical flow rate, the time-averaged velocity and Reynolds stress decrease slightly, and the cumulative energy fraction decreases at flow skirt and vortex suppression plate.

Analytical model of eddy current bobbin coil probe responses at support plates in steam generator and heat exchanger tubes

The steam generators (SGs) of CANadian Deuterium Uranium nuclear reactors require periodic inspections to ensure their safe operation. Eddy current (EC) testing is the primary method by which the SG tubes are inspected. Many conditions in the SG tubes affect the EC response, such as fretting, pitting, cracking, as well as tube expansion, and the presence of tubesheet and support structures. When two or more of these parameters overlap, the EC signals from degradation induced wall losses are frequently difficult to interpret because these wall loss signals are often distorted due to interference with background signal variations. In this paper, a novel analytical model that describes the impedance of a bobbin coil with a plate encircling an arbitrary number of cylindrical conductors is developed. The model is validated against finite element method modelling and experiment. This model can be used to simulate the main probe response, while inspecting SG tubes near the tubesheet and support structures and thereby, provides the potential to separate out smaller flaw responses.

Evaluation of the durability of cementicious composites reinforced with natural vegetable fibers from the Amazon

The study of the use of plant fibers as reinforcement for cementitious composites has become increasingly common in recent years, thanks to the advancement of technologies and the demand for innovative and sustainable materials. In the Amazon, this resource is widely found and used for different applications, and the present work is interested in evaluating the use of these fibers as structural reinforcement of cement slabs. The mechanical and durability properties of cementitious composites reinforced with a content of 5% vegetable fibers from jute (Corchorus capsularis) and mallow (Urena lobata L.) were investigated. The objective was to evaluate the quality and performance of these fibers as reinforcement of cementitious plates for a possible use of these composites in Civil Construction. Spreading and thermogravimetry tests were carried out on the matrix and tensile tests in flexion at 4 points on the composites. The results obtained indicated that the fibers provided an increase in the flexural strength and toughness of the composites, as well as the use of metakaolinite as a pozzolanic material, contributed to increasing the durability of these composites, indicating a great possibility of using them in structural and semi-structural applications.

Biomechanical study on the treatment of Pauwels type III femoral neck fracture by open reduction and internal fixation with hollow nail internal fixation.

We aimed to explore the therapeutic effect of open reduction and internal fixation with hollow nail internal fixation for Pauwels type Ⅲ femoral neck fracture. From January 2016 to February 2021, a total of 100 eligible patients with Pauwels type III femoral neck fracture were involved in this study and divided into two groups randomly: the combined remedy group and the closed therapy group, with 50 patients in each group. After that, 50 subjects in the combined remedy group were treated with open reduction and support plate combined with hollow screw internal fixation, and the treatment conditions were observed and recorded. The closed therapy group received routine treatment. Among the 100 patients selected, the operation time of the combined remedy group was significantly lower than that of the closed therapy group, and the intraoperative bleeding was also significantly less. In the closed therapy group, the time of getting out of bed after the operation and the excellent and good rate were better; moreover, the functional score and pain score of three months after the operation were significantly better than that of one month after the operation. The functional score and pain score of one month after the operation were not statistically significant for the combined remedy group or the closed therapy group. In the treatment of Pauwels type Ⅲ femoral neck fracture with open reduction and internal fixation combined with hollow nail internal fixation, the operation time and intraoperative bleeding volume were significantly decreased, but the postoperative recovery time was enhanced compared to that of total joint replacement. After the operation, the functional score and pain score had a significant relationship with the recovery time, and there was no significant relationship with the type of treatment. Therefore, in clinical treatment, doctors should take appropriate treatment methods for their patients.