Optimal Repair Research Articles

Repair of Aerospace Composite Structures Using Liquid Thermoplastic Resin

In this study, two types of carbon-fiber-reinforced plastic (CFRP) composite scarf geometries were created using two scarf angles, i.e., 1.43° and 5.71°. The scarf joints were adhesively bonded using a novel liquid thermoplastic resin at two different temperatures. The performance of the repaired laminates was compared with pristine samples in terms of residual flexural strength using four-point bending tests. The repair quality of the laminates was examined by optical micrographs, and the failure modes after flexural tests were analyzed using a scanning electron microscope. The thermal stability of the resin was evaluated by thermogravimetric analysis (TGA), whereas the stiffness of the pristine samples was determined using dynamic mechanical analysis (DMA). The results showed that the laminates were not fully repaired under ambient conditions, and the highest recovery strength at room temperature was only 57% of the total strength exhibited by pristine laminates. Increasing the bonding temperature to an optimal repair temperature of 210 °C resulted in a significant improvement in the recovery strength. The best results were achieved for laminates with a higher scarf angle (5.71°). The highest residual flexural strength was recorded as 97% that of the pristine sample repaired at 210 °C with a scarf angle of 5.71°. The SEM micrographs showed that all the repaired samples exhibited delamination as the dominant failure mode, whereas the pristine samples exhibited dominant fiber fracture and fiber pullout failure modes. The residual strength recovered using liquid thermoplastic resin was found to be much higher than that reported for conventional epoxy adhesives.

Ascorbic Acid 2-Phosphate-Releasing Supercritical Carbon Dioxide-Foamed Poly(L-Lactide-Co-epsilon-Caprolactone) Scaffolds Support Urothelial Cell Growth and Enhance Human Adipose-Derived Stromal Cell Proliferation and Collagen Production

Tissue engineering can provide a novel approach for the reconstruction of large urethral defects, which currently lacks optimal repair methods. Cell-seeded scaffolds aim to prevent urethral stricture and scarring, as effective urothelium and stromal tissue regeneration is important in urethral repair. In this study, the aim was to evaluate the effect of the novel porous ascorbic acid 2-phosphate (A2P)-releasing supercritical carbon dioxide-foamed poly(L-lactide-co-ε-caprolactone) (PLCL) scaffolds (scPLCLA2P) on the viability, proliferation, phenotype maintenance, and collagen production of human urothelial cell (hUC) and human adipose-derived stromal cell (hASC) mono- and cocultures. The scPLCLA2P scaffold supported hUC growth and phenotype both in monoculture and in coculture. In monocultures, the proliferation and collagen production of hASCs were significantly increased on the scPLCLA2P compared to scPLCL scaffolds without A2P, on which the hASCs formed nonproliferating cell clusters. Our findings suggest the A2P-releasing scPLCLA2P to be a promising material for urethral tissue engineering.

Functional and MRI Outcomes After In Situ Repair Versus Tear Completion Before Repair of Bursal-Side Partial-Thickness Rotator Cuff Tears.

The optimal repair method for bursal-side partial-thickness rotator cuff tears (PTRCTs) involving >50% of the thickness remains a controversial topic. The study was aimed to compare the functional and magnetic resonance imaging (MRI) outcomes after in situ repair or tear completion before repair of bursal-side PTRCTs. A retrospective clinical study was conducted involving 58 patients who underwent in situ repair or tear completion before repair of bursal-side PTRCTs between January 2019 and December 2020. These patients were divided into two groups: the in situ repair group and the tear completion before repair group. Functional assessment consisted of active range of motion (ROM), visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES) score, and Constant-Murley score. The percentages of patients in each group achieving the minimal clinical important difference (MCID) of the functional scores were determined. The healing status of the rotator cuff was assessed by postoperative MRI. There were no statistically significant differences between the two groups in terms of demographic data. The mean follow-up period was 14.53 ± 2.64months in the in situ repair group and 15.40 ± 2.66months in the tear completion before repair group. At the final follow-up, the forward elevation, external rotation, and internal rotation improved significantly in both groups. The VAS, ASES score, and Constant-Murley score improved significantly in the in situ repair group (5.17 ± 2.00 points to 0.11 ± 0.41 points, p=0.001; 44.04 ± 17.40 points to 95.47 ± 4.32 points, p=0.001; 49.50 ± 14.38 points to 93.50 ± 3.49 points, p=0.001) and in the tear completion before repair group (5.43 ± 3.32 points to 0.03 ± 0.18 points, p=0.001; 41.50 ± 19.59 points to 95.94 ± 2.68 points, p=0.001; 47.54 ± 17.13 points to 93.97 ± 2.61 points, p=0.001). Postoperative MRI revealed that the re-tear rate was 7.1% (2/28) in the in situ repair group and 3.3% (1/30) in the tear completion before repair group. No significant differences were observed in terms of the functional scores, the percentages of patients achieving the MCID of the functional scores, and the re-tear rate between the two groups (p > 0.05). Both in situ repair and tear completion before repair yielded satisfactory clinical outcomes for patients with bursal-side PTRCTs. No significant differences were observed in the functional and MRI outcomes between the two groups.

A REPAIR REPLACEMENT PROBLEM FOR COLD STANDBY SYSTEM USING ALPHA SERIES AND GEOMETRIC PROCESS

The present paper studies a cold standby repairable system consisting of two identical components namely component 1, component 2 and onerepairman is studied. Assume that each component after repair is not 'as good as new' and also the successive working times form a decreasing a-series process, the successive repair time's form an increasing geometric process and both the processes are exposing to exponential failure law. Under these assumptions we study an optimal replacement policy N in which we replace the system when the number of failures of component 1 reaches N. It can be determined that an optimal repair replacement policy N* such that the long run average cost per unit time is minimized. It can also be derived an explicit expression of the long-run average cost and the corresponding optimal replacement policy N* can be determined analytically. Numerical results are provided to support the theoretical results

PMDS Array Codes With Small Sub-Packetization, Small Repair Bandwidth/Rebuilding Access

Partial maximum distance separable (PMDS) codes are a kind of erasure codes where the nodes are divided into multiple groups with each forming an MDS code with a smaller code length, thus they allow repairing a failed node with only a few helper nodes and can correct all erasure patterns that are information-theoretically correctable. However, the repair of a failed node of PMDS codes still requires a large amount of communication if the group size is large. Recently, PMDS array codes with each local code being an MSR code were introduced to reduce the repair bandwidth further. However, they require extensive rebuilding access and unavoidably a significant sub packetization level. In this paper, we first propose two constructions of PMDS array codes with two global parities that have smaller sub-packetization levels and much smaller finite fields than the existing one. One construction can support an arbitrary number of local parities and has $(1+\epsilon)$-optimal repair bandwidth (i.e., $(1+\epsilon)$ times the optimal repair bandwidth), while the other one is limited to two local parities but has significantly smaller rebuilding access and its sub packetization level is only $2$. In addition, we present a construction of PMDS array code with three global parities, which has a smaller sub-packetization level as well as $(1+\epsilon)$-optimal repair bandwidth, the required finite field is significantly smaller than existing ones.

Outcomes and complications of primary rhegmatogenous retinal detachment repair with pars plana vitrectomy in young adults

BackgroundScleral buckling has been the standard for rhegmatogenous retinal detachment repair in young patients given the typical lack of posterior vitreous detachment, phakic status, and lower risk of proliferative vitreoretinopathy. In older patients, pars plana vitrectomy alone is typically used for rhegmatogenous retinal detachment repair. We report the outcomes and complications of pars plana vitrectomy for rhegmatogenous retinal detachment in young eyes.MethodsRetrospective, single-center cohort study. Medical records of patients between 15 to 45 years of age undergoing primary pars plana vitrectomy for rhegmatogenous retinal detachment repair between 2010 and 2020 were carefully reviewed. All analyses were performed using the Kruskal–Wallis tests for numeric covariates between age groups.ResultsEyes were stratified by age: 15–24 (group 1, n = 10), 25–34 (group 2, n = 14), and 35–45 (group 3, n = 38). The average number of surgeries were 1.9, 1.4, and 1.1 in groups 1, 2, and 3, respectively (p = 0.004). Single surgery success rates were 50%, 64%, and 92% in groups 1, 2 and 3, respectively (p = 0.005). Final reattachment rates were 80%, 93%, 100% in groups 1, 2, and 3, respectively (p = 0.568). Proliferative vitreoretinopathy developed in 50%, 7%, and 8% of eyes in groups 1, 2, and 3, respectively (p < 0.001).ConclusionWhile the final reattachment rates were excellent in all groups, the higher rates of proliferative vitreoretinopathy and lower single surgery success rate in younger patients may suggest that primary pars plana vitrectomy may not be the optimal repair method in these age groups.

Fracture properties of a concrete-epoxy mortar interface with precoating treatment applied through image correlation technology

Random defects on concrete surfaces are a key factor affecting the bonding property of concrete–epoxy mortar interfaces. In this study, an epoxy–acetone solution was employed to pretreat such defects on concrete surfaces, and resin concentrations of 20, 40, 60, and 80 wt% diluted by acetone were used. The fracture mechanical properties and propagations of the fracture process zone (FPZ) of 14 concrete–epoxy mortar composite specimens were analysed using digital image correlation technology and the four-point bending test. The results revealed that there was a great influence of resin concentration on the fracture properties of the concrete-epoxy mortar interface. Precoating solution with an appropriate resin concentration (20 ∼ 40 wt%) could effectively delay crack formation at the interface and markedly improve the bearing capacity, stiffness, ductility, FPZ length, and energy release rate of the specimens. The precoating solution with a resin concentration of 40 wt% exhibited the optimal repair effect on the concrete surfaces. However, the improvement from the pretreatment with high resin concentrations (60 ∼ 80 wt%) on the fracture properties was less than satisfactory. The toughening mechanism of this precoating solution was analysed through scanning electron microscopy, which revealed that the concrete surface could be effectively repaired and improved by the precoating treatment with an appropriate resin concentration, which in turn enhanced the interfacial connection performance between epoxy mortar and concrete.

Queueing and Reliability Analysis of Unreliable Multi-server Retrial queue with Bernoulli feedback

The study consists of an unreliable multiserver retrial queue with feedback where clients may resist to join the orbit and the service provider is erratic. In this model we have considered c service providers at a time and if all the c servers are busy, the incoming clients wait in the retrial orbit. The model is unfolded using Matrix Geometric Method (MGM) to obtain the rate matrix and stationary probabilities. The system with retrials is modelled and the performance measures and reliability indices are procured. These derived quotients are then visualised and validated with the help of tables and graphs. Further, the cost analysis of the model is carried out and the optimal cost for the system is obtained using Particle Swarm Optimization (PSO) algorithm for matrix method. The optimal repair and retrial rates are obtained using PSO technique which helps the computer and manufacturing industry to work towards better decision policies.

Role of Endovascular Stenting in Patients with Traumatic Iliac Artery Injury.

Common and external iliac artery injuries (IAI) portend significant morbidity and mortality. The goal of this study was to examine the impact of mechanism of injury and type of repair on outcomes and identify the optimal repair for patients with traumatic IAI using a large, national dataset. Patients undergoing operative repair for IAI were identified from the Trauma Quality Improvement Program database during a 5-year timespan, ending in 2019. Age, sex, race, severity of injury, severity of shock, type of iliac repair (open or endovascular), mechanism, morbidity and mortality were recorded. Patients with IAI were stratified by both type of repair and mechanism and compared. Multivariable logistic regression analysis was used to identify independent predictors of mortality. Operative IAI was identified in 507 patients. Of these injuries, 309 (61%) were penetrating and 346 (68.2%) involved the external iliac artery. The majority of patients were male (82%) with a median age and ISS of 31 and 20, respectively. Endovascular repair was performed in 31% of cases. For patients with penetrating injuries, the type of repair impacted neither morbidity nor mortality. For blunt-injured patients, endovascular repair was associated with lower morbidity (29.3% vs 41.3%; p = 0.082) and significantly reduced mortality (14.6% vs 26.7%; p = 0.037) compared with the open-repair approach. Multivariable logistic regression identified endovascular repair as the only modifiable risk factor associated with decreased mortality (odds ratio 0.34; 95% CI 0.15 to 0.79; p = 0.0116). Traumatic IAI causes significant morbidity and mortality. Endovascular repair was identified as the only modifiable predictor of decreased mortality in blunt-injured patients with traumatic IAI. Therefore, for select patients with blunt IAIs, an endovascular repair should be the preferred approach.

Availability Optimization Decision Support Design System for Different Repairable n-Stage Mixed Systems

This study attempts to propose an availability optimization decision support design system for repairable n-stage mixed systems, in which different combinations of subsystems, such as parallel, standby, and k-out-of-q, are connected in series configuration. The enumeration method, tabu search, simulated annealing, non-equilibrium simulated annealing, and the modified redundancy allocation heuristic combined with a modified genetic algorithm will be proposed to solve the system availability optimization problem and further determine the appropriate system configuration design. Several simulated cases are conducted by following the procedural flow of the proposed availability optimization decision support design system to reach the optimal allocations of the component redundancy amount, the optimal repair rates, and the optimal failure rates of all subsystems to minimize the total system cost under several configuration constraints for different repairable n-stage mixed systems. Simulated results display that the proposed availability optimization decision support design system can definitely take advantage of different component redundancy system designs, including the parallel-series system, n-stage standby system, n-stage k-out-of-q system, and n-stage mixed system, to save a lot of cost and meet the high level of the system availability requirement compared to the n-stage single component series system. Additionally, the results for all proposed combined methods also show that the parallel-series system can obviously reach the same level of system availability requirement with less system total cost, in contrast to the n-stage standby system, by presuming the identical deteriorating probability for both the operating components and the standby components. The performance comparisons of five proposed combined methods for four proposed system configurations are analyzed comprehensively. It can be concluded that the performances of the modified redundancy allocation heuristic method, combined with a modified genetic algorithm on the criteria of the optimal system costs for four proposed system configurations, are not only superior to the other four combined methods, but also to the performances on the criteria of CPU running time for four proposed system configurations.

Multicompartment pelvic floor prolapse repairs: Surgical principles

The operative management of rectal prolapse has evolved substantially over time. Many patients with rectal prolapse also have concomitant prolapse of their anterior and/or middle compartments. Optimal repair of pelvic organ prolapse will address all of the involved compartments, which often requires close collaboration with a urogynecology or female urology team. This chapter describes our technique for robotic ventral mesh rectopexy with sacrocolpopexy when indicated.

Native and Post-Repair Residual Mitral Valve Prolapse Increases Forces Exerted on the Papillary Muscles: A Possible Mechanism for Localized Fibrosis?

Recent studies have linked mitral valve prolapse to localized myocardial fibrosis, ventricular arrhythmia, and even sudden cardiac death independent of mitral regurgitation or hemodynamic dysfunction. The primary mechanistic theory is rooted in increased papillary muscle traction and forces due to prolapse, yet no biomechanical evidence exists showing increased forces. Our objective was to evaluate the biomechanical relationship between prolapse and papillary muscle forces, leveraging advances in ex vivo modeling and technologies. We hypothesized that mitral valve prolapse with limited hemodynamic dysfunction leads to significantly higher papillary muscle forces, which could be a possible trigger for cellular and electrophysiological changes in the papillary muscles and adjacent myocardium. We developed an ex vivo papillary muscle force transduction and novel neochord length adjustment system capable of modeling targeted prolapse. Using 3 unique ovine models of mitral valve prolapse (bileaflet or posterior leaflet prolapse), we directly measured hemodynamics and forces, comparing physiologic and prolapsing valves. We found that bileaflet prolapse significantly increases papillary muscle forces by 5% to 15% compared with an optimally coapting valve, which are correlated with statistically significant decreases in coaptation length. Moreover, we observed significant changes in the force profiles for prolapsing valves when compared with normal controls. We discovered that bileaflet prolapse with the absence of hemodynamic dysfunction results in significantly elevated forces and altered dynamics on the papillary muscles. Our work suggests that the sole reduction of mitral regurgitation without addressing reduced coaptation lengths and thus increased leaflet surface area exposed to ventricular pressure gradients (ie, billowing leaflets) is insufficient for an optimal repair.

Failure contingency assessment of corroded beams based on structural parameters

The effects of corrosion in the serviceability state and capacity state on the failure contingency, life cycle cost (LCC) and optimum repair time (ORT) of reinforced concrete beams were evaluated. Gradual corrosion-induced crack widths were obtained using the cohesive crack model. Deterioration of flexural capacity was examined through a simplified three-dimensional finite-element model. Considering the crack width and capacity as random variables in the gamma process, the LCC and ORT were investigated using a renewal process. Analysis of the effective parameters indicated that the corrosion rate in the serviceability state and the tensile rebar ratio in the capacity state had the most significant effects on the probability of failure (PoF), the LCC and the ORT. With a decrease in the corrosion rate, the PoF reduced and the ORT increased. With an increase in the aspect ratio of the section, the LCC increased and the ORT declined.

Enhanced DNA repair through droplet formation and p53 oscillations

Living organisms are constantly exposed to DNA damage, and optimal repair is therefore crucial. A characteristic hallmark of the response is the formation of sub-compartments around the site of damage, known as foci. Following multiple DNA breaks, the transcription factor p53 exhibits oscillations in its nuclear concentration, but how this dynamics can affect the repair remains unknown. Here, we formulate a theory for foci formation through droplet condensation and discover how oscillations in p53, with its specific periodicity and amplitude, optimize the repair process by preventing Ostwald ripening and distributing protein material in space and time. Based on the theory predictions, we reveal experimentally that the oscillatory dynamics of p53 does enhance the repair efficiency. These results connect the dynamical signaling of p53 with the microscopic repair process and create a new paradigm for the interplay of complex dynamics and phase transitions in biology.

Laparoscopic Resection of Cesarean Scar Pregnancy at 11 Weeks Gestational Age

<h3>Study Objective</h3> To demonstrate a laparoscopic technique for resection of cesarean scar pregnancy (CSP) and revision of cesarean scar defect. <h3>Design</h3> We present a stepwise narrated demonstration of our technique of a resection of a CSP. <h3>Setting</h3> Referral Center in NY. <h3>Patients or Participants</h3> 33-year-old with cesarean scar pregnancy at 11 weeks gestational age, desiring fertility sparing treatment <h3>Interventions</h3> A retroperitoneal dissection is performed, and the uterine blood supply is isolated<b>.</b> Hemostatic control is achieved with the use of intrauterine vasopressin and temporary occlusion of the uterine blood supply. The bladder is carefully dissected from the lower uterine segment and cesarean scar pregnancy. Ultrasound guidance is used to assist in hysterotomy location for resection of the ectopic pregnancy. The myometrium is repaired with a 3-layer closure. Uterine ventrosuspension by plication of the round ligaments bilaterally results in anteversion of the previously sharply retroverted uterus, reducing tension on the repair. Hysteroscopy under laparoscopic visualization confirms repair of the scar defect. <h3>Measurements and Main Results</h3> Successful laparoscopic resection of a cesarean scar ectopic pregnancy and resection of scar defect with EBL of 250 mL. Patient discharged home postoperative day one. Normal appearing uterus on 3-month follow-up MRI with no residual cesarean scar defect and residual myometrial thickness of 1.6 cm. <h3>Conclusion</h3> Laparoscopic resection provides a means of addressing cesarean scar pregnancy at advanced gestational age while repairing the associated cesarean scar defect. Control of the uterine blood supply and mobilization of the bladder are critical aspects of the surgery. Intraoperative ultrasound and laparoscopic guided hysteroscopy can ensure full resection of the defect and achieve optimal repair. For the retroverted uterus, ventrosuspension may avoid tension on the repair to promote healing. For this patient, our technique resulted in no residual cesarean scar defect on follow-up imaging.

Sustainable Restoration of Ancient Architectural Patterns in Fujian Using Improved Algorithms Based on Criminisi

Based on current manual restoration methods, a better algorithm for restoring images based on sample blocks is proposed, along with a sustainable restoration technique for digital virtualization, with the aim of preserving and restoring the priceless art of ancient architectural motifs. The paper uses curve fitting to pre-process the restored photos by re-constructing their damaged borders and filling in the structural information that is absent with the aid of an enhancement of the Criminisi method. The repaired photos have improved edges that were previously blurry, fractured, and over-extended. In order to increase the dependability of the priority calculation when restoring photos and make it possible to acquire a more precise restoration order, we rewrote the priority calculation formula for restoration blocks in the Criminisi algorithm. The purpose was to enhance the aesthetics of the photographs and provide a viable and sustainable restoration technique for the restoration of ancient architectural motifs in Fujian. The Criminisi algorithm with deep learning is used in the thesis to fully restore the content, color, and texture of the architectural photographs, bringing the murals as close to their original state as is practical. In order to improve the blurry, broken, and over-extended edges of the restored images, the broken edges of the images are first repaired through image pre-processing. Then, adjustment factors are added to the priority calculation to increase the weight of the data items, resulting in a more accurate priority order while preventing the priority values from degrading quickly in the later stages of restoration. The PSNR values of the restored images were calculated and compared to those of the Criminisi method, demonstrating that the revised algorithm produces better restoration results and can effectively improve restoration efficiency while lowering restoration costs and ensuring pattern restoration sustainability. By retaining as much of the structural information of the original image as possible in the design of the network model and allocating larger weights to the structural part, this process also uses style migration in deep learning to restore the texture and color of the mural. As a result, the final image is as similar to the original image as possible in terms of content and as similar as possible to the style image in terms of color and texture. A better solution is proposed based on the Criminisi algorithm. By comparing the experimental results of the three sets of building images, the PSNR values of the priority improvement algorithm (30.26, 38.06, 39.56) were significantly better than those of the Criminisi algorithm (27.59, 37.06, 37.59), using the peak signal-to-noise ratio (PSNR) values as a reference standard. In order to determine the appropriate restoration sequence and enhance the quality of picture repair, the broken edges of the pattern are strengthened. The algorithm’s matching criteria can be applied in subsequent work to improve sample-matching accuracy and produce better sustainable restoration results for ancient architectural patterns in Fujian. It no longer requires specialized professional knowledge to reproduce the color of faded architectural photos; instead, a style migration approach is employed to recover the color and texture of architectural images. This study proposes the use of a texture synthesis method and a layered processing method through which the PSNR values of the resulting restored images calculated are superior and significantly higher than those of the sample-based method and the variational framework of synthetic images with regular texture components. We achieved the creation of an updated Criminisi algorithm-based solution that improves the quality of image restoration by fortifying the pattern’s frayed edges and determining the optimum repair order. These two techniques can be combined to improve the sustainability of restoration of faded architectural photographs for issues such as pattern breakage, color loss and fading. To achieve better restoration results for the historic architectural patterns in Fujian, the accuracy of sample matching can be increased, starting with the algorithm’s matching criterion.

Excessively High Repair Tension Decreases Microvascular Blood Flow Within the Rotator Cuff

Background: Repair tension and microvascular blood flow within the rotator cuff has a critical impact on tendon healing after rotator cuff repair. However, the relationship between repair tension and microvascular blood flow within the rotator cuff remains unclear. Purpose/Hypothesis: The purpose of this study was to determine how much tension adversely affects microvascular blood flow within the rotator cuff. The hypothesis was that as the repair tension increases, the microvascular blood flow within the rotator cuff decreases. Study Design: Controlled laboratory study. Methods: Repair tension and microvascular blood flow within the rotator cuff of 30 patients with full-thickness rotator cuff tears were simultaneously measured using a digital tension meter and a contact-type laser Doppler flowmeter, respectively. Microvascular blood flow was measured under 4 levels of tension (0, 10, 20, and 30 N) at 5 points on the rotator cuff. The obtained values were statistically analyzed by a linear mixed-effects model to clarify the effect of tension on microvascular blood flow within the rotator cuff. Results: There was no statistically significant difference in microvascular blood flow (mL/min/100 g) within the rotator cuff between 0 N (mean, 3.51; 95% CI, 3.0-4.0) and 10 N (mean, 3.74; 95% CI, 3.2-4.3) of tension (P = .716). However, there were statistically significant differences in microvascular blood flow within the rotator cuff between 0 and 20 N of tension (mean, 2.84; 95% CI, 2.3-3.4) (P = .002) and between 0 and 30 N of tension (mean, 2.45; 95% CI, 1.9-3.0) (P < .001). Conclusion/Clinical Relevance: Our findings indicate that tension of ≥10 N during rotator cuff repair significantly decreases the microvascular blood flow within the rotator cuff. These data will contribute to determining the optimal repair tension during rotator cuff repair.

Decision Support System for Optimum Repair Technique of Concrete Bridges Girders in Egypt

Nowadays, value engineering (VE) has become an essential application in many fields, especially structural engineering. Bridges normally experience local damages throughout their service life, whether due to natural hazards, accidents, or harsh environmental conditions. These damages can compromise the integrity of the structure based on their severity. This paper aims to develop a decision support system (DSS) that selects the most optimal repair technique for girders of concrete bridges, considering different factors such as financial, technical, and logistical factors. The proposed DSS is developed by integrating the analytical hierarchy process (AHP) and VE to specify the optimum repair technique. Furthermore, the most common repair techniques are considered in this research, such as repairing using Steel plates, sheets of glass fiber reinforced polymers (GFRPs), laminates of carbon fiber reinforced polymers (CFRPs), external pre-stressing cables, and concrete jackets. The developed (DSS) was presented graphically as a map for the optimum repairing technique for certain (span, span/depth) combinations. Finally, the DSS was verified using collected case studies from the literature and showed good matching within the considered range of girder’s dimensions.

Residual Stress Redistribution Analysis in the Repair Welding of AA6082-T6 Aluminum Alloy Joints: Experiment and Simulation.

Residual stress has a three-dimensional scale effect (length, depth, and width) in the process of repair welding, which has a detrimental impact on the service of the aluminum alloy welded structures in high-speed trains. This paper aims to systematically analyze the effects of the repair welding dimension on the residual stress redistribution and obtain the optimal repair welding principles. A combination of blind-hole drilling method and stress linearization in BS7910 was adopted to investigate residual stress redistribution under various repair welding dimensions. The results indicate that repair welding dimension was in accordance with the principle of “SNL (shallow, narrow and long)” and the optimal repair length, depth, and width of butt joints in this study were 15t, 0.25t, and t, respectively (t is the plate thickness of butt joints).

Less postoperative pain and shorter length of stay after robot-assisted retrorectus hernia repair (rRetrorectus) compared with laparoscopic intraperitoneal onlay mesh repair (IPOM) for small or medium-sized ventral hernias.

The optimal repair of ventral hernia remains unknown. We aimed to evaluate the results after robotic-assisted laparoscopic transabdominal repair with retrorectus mesh placement (rRetrorectus) compared with laparoscopic intraperitoneal onlay mesh repair (IPOM) for patients with small- or medium-sized ventral hernia. This was a retrospective cohort study of consecutive patients undergoing elective rRetrorectus or IPOM repair for small or medium-sized primary ventral or incisional hernias. The primary outcome was the postoperative need for transverse abdominis plane (TAP) block or epidural analgesia, secondary outcomes were length of stay and postoperative complications. All patients were followed for 30days postoperatively. A total of 59 patients were included undergoing rRetrorectus (n = 27) and IPOM (n = 32). Patients in the two groups were comparable in terms of age, sex, comorbidities, smoking status, body mass index (BMI), and type of hernia. The median fascial defect area was slightly larger in the rRetrorectus group (9 cm2 vs. 6.2 cm2, P = 0.031). The duration of surgery was longer for rRetrorectus (median 117.2min. vs. 84.4, P = 0.003), whereas the postoperative need for TAP block or epidural analgesia was less after rRetrorectus compared with IPOM (3.7% versus 43.7%, P = 0.002). There were no severe complications or reoperations after either procedure. The length of stay was shorter after rRetrorectus (median 0 vs. 1day, P < 0.001). rRetrorectus was associated with reduced postoperative analgesic requirement and shorter length of stay compared with laparoscopic IPOM. Registration Clinicaltrial.gov: NCT05320055.