Repair Technology Research Articles

Solid-state friction rolling repair technology for various forms of defects through multi-layer multi-pass deposition

The current Friction Stir Welding (FSW) based solid-state defect repairing method is an ideal repair technology for high-strength aluminum alloy. However, due to the limitation of pin length and the existence of shoulder, the stirring pin cannot penetrate deep into the root of defects and is difficult to extend in the width direction, which poses great challenges for components with large defects, such as one-dimensional, two-dimensional and volume defects. To overcome these limitations, this study successfully achieved effective repair of various forms of defects using the solid-state Friction Rolling Repair (FRR) technology through multi-layer multi-bead deposition. The microstructure and mechanical properties of the repaired ZL114A cast aluminum alloy joints were investigated. The results demonstrate well-bonded repaired boundaries, significant grain refinement at the junction between the repaired area and boundary, and ultimate tensile strength exceeding 80 % of base material strength. The average grain size of the repaired area can reach a minimum of 2.82 μm. The grain refinement degree of the side joint of the surface defect repair sample is higher than that of the bottom joint, and the corner joint of the bottom surface shows the highest proportion of recrystallized grains. Fracture locations were consistently within the interior of the repair zone in tensile specimens, indicating superior properties at side joints compared to those within the interior. The research proves that FRR has the ability to repair a variety of typical defects, including one-dimensional, two-dimensional and volume defects, in the process of processing and service, which lays a foundation for the industrial application of FRR.

Comparative Efficacy of Endogenous Stem Cells Recruiting Hydrogels and Stem Cell-loaded Hydrogels in Knee Cartilage Regeneration: A Meta- analysis.

Cartilage defects remain a challenge in diseases such as osteoarthritis (OA) and fractures. Scientists have explored the use of hydrogels in conjunction with stem cell technology as a tissue engineering method to treat cartilage defects in joints. In recent years, research into hydrogels containing stem cell technology for cartilage repair has mainly focused on two categories: stem cell-loaded hydrogels and endogenous stem cell recruiting hydrogels. The latter, utilizing cell-free products, represents a novel concept with several advantages, including easier dose standardization, wider sources, and simpler storage. This meta-analysis aims to assess and compare the therapeutic effects of endogenous stem cell recruiting hydrogels and stem cell-loaded hydrogels in promoting articular cartilage regeneration in animal models, with the goal of exploring endogenous stem cell recruiting hydrogels as a promising replacement therapy for knee cartilage regeneration in preclinical animal studies. We systematically searched PubMed, Web of Science, Cochrane Library, and Embase until January 2023 using key words related to stem cells, cartilage regeneration and hydrogel. A random-effects meta-analysis was performed to evaluate the therapeutic effect on newborn cartilage formation. Stratified analyses were also carried out by independently classifying trials according to similar characteristics. The level of evidence was determined using the GRADE method. Twenty-eight studies satisfied the inclusion criteria. Comprehensive analyses revealed that the use of endogenous stem cell recruiting hydrogels significantly promoted the formation of new cartilage in the knee joint, as evidenced by the histological score (3.77, 95% CI 2.40, 5.15; p < 0.0001) and the International Cartilage Repair Society (ICRS) macroscopic score (3.00, 95% CI 1.83, 4.18; p = 0.04), compared with the control group. The stem cell-loaded hydrogels also increased cartilage regeneration in the knee with the histological score (3.13, 95% CI 2.22, 4.04; p = 0.02) and the ICRS macroscopic score (2.49, 95% CI 1.16, 3.82; p = 0.03) in comparison to the control. Significant heterogeneity between studies was observed, and further stratified and sensitivity analyses identified the transplant site and modelling method as the sources of heterogeneity. The current study indicates that both endogenous stem cell recruiting hydrogels and stem cell loaded hydrogels can effectively promote knee joint cartilage regeneration in animal trials.

Mechanical Properties and Cooperation Mechanism of Corroded Steel Plates Retrofitted by Laser Cladding Additive Manufacturing under Tension.

As a metal additive manufacturing process, laser cladding (LC) is employed as a novel and beneficial repair technology for damaged steel structures. This study employed LC technology with 316 L stainless steel powder to repair locally corroded steel plates. The influences of interface slope and scanning pattern on the mechanical properties of repaired specimens were investigated through tensile tests and finite element analysis. By comparing the tensile properties of the repaired specimens with those of the intact and corroded specimens, the effectiveness of LC repair technology was assessed. An analysis of strain variations in the LC sheet and substrate during the load was carried out to obtain the cooperation mechanism between the LC sheet and substrate. The experimental results showed that the decrease in interface slope slightly improved the mechanical properties of repaired specimens. The repaired specimens have similar yield strength and ultimate strength to the intact specimens and better ductility as compared to the corroded specimen. The stress-strain curve of repaired specimens can be divided into four stages: elastic stage, substrate yield-LC sheet elastic stage, substrate hardening-LC sheet elastic stage, and plastic stage. These findings suggest that the LC technology with 316 L stainless steel powder is effective in repairing damaged steel plates in civil engineering structures and that an interface slope of 1:2.5 with the transverse scanning pattern is suitable for the repair process.

“In My Experience…Development of Novel Transosseous Rotator Cuff Repair Techniques and Technologies”

The author reviews his experience with transosseous rotator cuff repair techniques and technologies

Electrodes combined with permeable reaction barrier removes Cr (Ⅵ) from low permeability aquifers

Choosing an effective means of dealing with chromium (Cr (VI)) pollution is necessary. Electrokinetic (EK) technology is widely used in low- permeability aquifers. Zero-valent iron/activated carbon (ZVI/AC) can be used as a permeable reactive barrier (PRB) filler for the removal of Cr(Ⅵ) from in low- permeability media. However, the combined effects of these two technologies on aquifers have not been studied extensively. In this study, the ratio of zero-valent iron to activated carbon was determined through a pre-experiment. A series of batch experiment was then conducted to evaluate the effectiveness of electrokinetic (EK) combined with ZVI/AC-PRB on removal of Cr (VI). The ZVI/AC mixture before and after the reaction was analyzed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results of the batch experiment showed that the optimum removal efficiency of Cr (VI) was 90.38 % after 1440 min at a ZVI/AC mass ratio of 1:4. During the experiment, owing to the movement of the acid and base peaks, the pH of the anode region was generally lower than that of the other regions. The current decreased as the concentration of heavy metal ions decreased. The SEM, FTIR, and XPS results show that Cr (Ⅵ) was transformed into Cr(Ⅲ) or adsorbed on the surface under the action of ZVI/AC micro-electrolysis. In the present study, these two technologies were combined to treat Cr (VI)-contaminated aquifers. The experimental results provide a theoretical basis for the field application of the EK-PRB repair technology.

TECHNOLOGY OF STRUCTURAL REPAIR OF CONCRETE AND REINFORCED CONCRETE STRUCTURES OF WATERWORKS

The assessment of the current state of the water and land reclamation engineering infrastructure facilities, which was carried out on the basis of the analysis of technical documentation, visual, and instrumental examination of the structures' technical condition, confirms that as a result of long-term operation of the waterworks without proper reparation and restoration measures, their technical condition has significantly deteriorated. The most promising for the repair of concrete and reinforced concrete structures are cement-based materials modified with polymers (polymer concrete), which are dry mixtures of cement, sand, re-dispersible polymer powder (RPP) and other modifying additives. The research results of the redispersing polymer powders influence on the adhesive properties of repair composites are presented. It is shown that the modification of cement-sand solutions of RPP leads to a significant increase in the adhesive properties of repair composites. The optimally effective concentration of RPP in repair compositions has been found. The article highlights the technology of structural repair of concrete and reinforced concrete structures of the waterworks with the use of modern composite materials, which makes it possible to restore the design geometric indicators and the load-bearing capacity of the structures. The proposed technology and effective repair compositions help to carry out repair and restoration work on hydrotechnical structures of the water management and reclamation complex, in particular those destroyed or damaged as a result of the military aggression of the Russian Federation against Ukraine. The main principles of choosing the optimal technology for the structural repair of concrete and reinforced concrete structures of the waterworks, depending on the nature and degree of damage, the influence of technological and operational conditions on the structures' geometric indicators restoration during the modernization and reconstruction of reclamation systems in the post-war period, are revealed.

Repair of Underwater Concrete Cracks on Dam Surface: Optimization Analysis of the Grouting Process with Surface Sealing.

The grouting repair process of the sealing baffle on the surface of dam cracks can improve the repair slurry diffusion distance in the cracks; however, the process must be optimized. To address the problem of crack repair technology of underwater dam concrete with one section open and the other closed, a grouting analysis model was established. By adjusting various parameters in the grouting process, the influences of the grouting pressure, position of the grouting hole, diameter of the grouting hole, and water pressure on the diffusion of the Bingham fluid repair slurry in these cracks were studied. The results show that the grouting pressure and diameter of the grouting hole significantly influence the limited diffusion distance of Bingham fluid cement slurry in cracks. With an increase in grouting pressure and grouting hole diameter, the limiting distance of the front surface increases. The influences of the water pressure and position of the grouting hole are small. In addition, through correlation analysis, the degrees of influence of different factors can be sorted, providing the priority factors for actual operation construction.

360 Driving Technology for Endovascular Aortic Arch Repair: An International Analysis of Relay Branched Outcomes

Abstract Aim The introduction of endovascular aortic arch repair (EAR) represents a paradigm shift in the management of complex arch pathologies. In this multicentre study, a comparative analysis of international outcomes data on the single-, double- and triple-branch RELAY™ endografts is presented. Method Multicentre data was collected prospectively (2019-2022) and stored in an international registry. This was later retrieved and analysed retrospectively. All patients were followed-up for 24 months. Outcomes measured included target vessel patency (TVP), reintervention, stroke, and mortality. Results Of the total 148 patients, 17 (11.5%) received the single-branch RELAY™, 108 (73%) double-branch, and 23 (15.5%) triple-branch. The group characteristics were similar at baseline. Target vessel cannulation and technical success were achieved in 99.3% of patients. TVP at 30 days post-EAR was 100% in all groups, however, this became 93.8%, 74.0% and 100% at 24 months in the single-, double- and triple-branch endograft groups, respectively. As for reinterventions, these were only required with the double-branch RELAY™ (n=50, 34%). Similarly, disabling strokes were only observed in the double-branch group (n=35, 32.4%), and the overall study incidence was 23.8%. Non-disabling strokes had an overall incidence of 12.8% (n=19). The overall mortality rate was 2.7%, with all 4 deaths recorded occurring in the double-branch group. Logistic regression analysis showed a significant association between urgency (acute) and reintervention. Conclusions Our results clearly demonstrate that EAR using RELAY™ Branched is a highly efficacious strategy. Nevertheless, it seems that clinical outcomes with the single- and triple-branch RELAY™ are more favourable than with the double-branch configuration.

FEATURES OF WELL KILLING IN CONDITIONS OF CARBONATE RESERVOIR AND HIGH GOR

The article presents the results of studies on the use of well killing technology in fractured carbonate reservoirs of the Republic of Bashkortostan under conditions of loss of kill fluid and high GOR of the product. The geological and technical conditions of the Metelinskoye field are summarized, and the factors complicating well killing before routine and workover are described - reduced reservoir pressure during operation, previous large-volume salt-acid treatments, and the presence of hydrogen sulfide.The article substantiates the choice of invert-emulsion solutions (IER) for killing wells in the Metelinskoye field, taking into account the experience of using various killing technologies in the Volga-Ural oil and gas province. The authors have determined the physicochemical and rheological characteristics of kill compositions based on IER of various densities. An increase in the effective viscosity at high shear rates and the limit shear stress of the IER with an increase in the density of the composition was revealed. Taking into account the high risks of gas breakthrough during well killing in the Metelinskoye field, studies were also conducted to assess the gas-retaining capacity of the IER on an experimental installation by extruding the composition from a metal capillary. It has been shown that the gas holding capacity of these compositions with increasing density is described by an equation with a power function and a high degree of reliability. The effect of hydrogen sulfide neutralizer addition on IER properties was investigated. In order to increase the success of killing, the IER-based killing technology was selected and adapted to the existing conditions. The better blocking ability of higher density formulations has been confirmed. Successful well tests. To reduce the risks of using the IER and optimize the consumption of reagents during the further use of the technology, organizational and technical measures for killing and subsequent repair of wells were developed and implemented. The results of this work can be used in wells of the Ural-Volga region, Eastern Siberia and Timan-Pechora province with the presence of losses and a high gas factor, the repair of which is complicated by the lack of fluid circulation and the presence of excess pressure at the wellhead with signs of gas shows.

Fatecode enables cell fate regulator prediction using classification-supervised autoencoder perturbation

Cell reprogramming, which guides the conversion between cell states, is a promising technology for tissue repair and regeneration, with the ultimate goal of accelerating recovery from diseases or injuries. To accomplish this, regulators must be identified and manipulated to control cell fate. We propose Fatecode, a computational method that predicts cell fate regulators based only on single-cell RNA sequencing (scRNA-seq) data. Fatecode learns a latent representation of the scRNA-seq data using a deep learning-based classification-supervised autoencoder and then performs in silico perturbation experiments on the latent representation to predict genes that, when perturbed, would alter the original cell type distribution to increase or decrease the population size of a cell type of interest. We assessed Fatecode's performance using simulations from a mechanistic gene-regulatory network model and scRNA-seq data mapping blood and brain development of different organisms. Our results suggest that Fatecode can detect known cell fate regulators from single-cell transcriptomics datasets.

НАУЧНАЯ ШКОЛА ПРОФЕССОРА ПЕТРА ВАСИЛЬЕВИЧА СЕНИНА

The strategic task in the field of modern higher education is to develop the research potential of the university, to educate scientific staff. The effectiveness of this process depends on the successful functioning of scientific schools. In this regard, the research aimed at studying the experience of the author's scientific schools is relevant. (Research purpose) The research purpose is analyzing the concept and features of the scientific school as a form of personal growth and formation of researchers at the university using the example of research in the field of developing technologies for high-resource repair of machinery and technological equipment using metal coatings with specified functional properties (experience of the scientific school of professor P.V. Senin). (Materials and methods) Applied scientific and theoretical methods of analyzing the experience of the functioning of a scientific school, summarized and interpreted the criteria for its success as a form of personal growth and becoming a researcher at a university. Scientific and technical literature and publications in the field of humanitarian knowledge were used in the study. (Results and discussion) The experience of the P.V. Senin scientific school has shown that the implementation of the mechanisms of personal growth and formation of researchers at the university is the inclusion of students in the process of the scientific school, based on the creation of innovation centers, research laboratories, student teams, as well as the publication activity of the community of scientists on the basis of general theoretical and methodological approaches reflecting common research results. It was determined that the priority task of the scientific school is the interaction of university science and economic sectors aimed at creating technologies for high-resource repair of machines using the method of electric spark processing. (Conclusions) The results of the activities of the P.V. Senin scientific school allow us to consider this structure as a point of personal growth and professional development of a research student, a young scientist.

Electromigration effect of nano-Fe3O4 in concrete under chloride erosion environment

In order to improve the effectiveness of electro-migration repair technology, researchers have introduced new materials to address the adverse effects of electrochemical repair on concrete, such as interface softening in reinforced concrete. In this study, a dispersed solution of nano-Fe3O4 was selected as the anode electrolyte. Concrete specimens were subjected to electric treatment for repair, and the entry of nano particles into the concrete under the action of an external electric field was investigated. The microstructure and mechanical properties of the repaired concrete material were analyzed using techniques such as potentiodynamic polarization curve, chemical titration, scanning electron microscopy, energy spectrum analysis, mercury intrusion porosimetry, and pull-out test. The results showed that after 15 days of electrochemical nano-repair, the passivation film on the steel reinforcement was repaired, resulting in a 57 % reduction in corrosion rate and prevention of further chloride ingress, thus improving the corrosion resistance of the reinforcement. Furthermore, the electrochemical nano-repair did not affect the outward migration of chloride ions from the concrete, with a chloride removal efficiency as high as 72.6 %. When the treatment duration was 15 days and the current density was 3 A/m2, the bond strength exhibited the greatest improvement, with an increase of 99.15 %. Compared to electrochemical chloride removal, the electrochemical nano-repair reduced the porosity in the middle and inner layers by 17.8 % and 14.8 %, respectively. Microstructural analysis revealed that the electromigrated nano-Fe3O4 particles were uniformly dispersed within the concrete, replacing harmful byproducts and filling the pores.

Analysis of Road Bridge Repair and Strengthening Construction Technology

Highway infrastructure plays a crucial role in the healthy development of the social economy. Therefore, China has invested a lot of financial resources in the construction of road and bridge projects in recent years, resulting in the rise in scale and number of road and bridge projects. Simultaneously, the quality of road bridges has garnered widespread attention, necessitating an exploration of common hazards associated with road bridges and the significance of their reinforcement. It is essential to delve into specific technical methods to enhance the quality and service life of road bridges. This paper elaborates on the common hazards faced by road bridges and proposes maintenance and reinforcement strategies to promote the healthy development of road bridge engineering.

Development of the scientific and pedagogical school of the department “Ground Transport and Technological Complexes”

The scientific article reflects the main stages of the historical development of the scientific and pedagogical school of the cycle “Technology of structural metals. Materials Science”, which is one of the areas of the department “Ground transport and technological complexes”. Employees of the department made a significant contribution to solving practical problems in assessing the effectiveness of existing technological processes for restoring the tread surface profile of wheel pairs of wheels, the proposed processes of face milling and turning when restoring the wheel rim profile, including the use of preliminary induction annealing to improve machinability, optimization of cutting conditions wheels based on linear and nonlinear programming methods. A large amount of research and implementation work has been carried out to improve the repair technology and increase the reliability of the wheel-motor unit of rail crews of railway rolling stock. Issues related to surfacing operations during repairs and increasing the wear resistance of deposited surfaces were considered.At the same time, the teachers of the department conduct training sessions on disciplines at a high methodological level, without which it is impossible to imagine a modern engineer.Over the years of work of the cycle “Technology of Structural Metals. Materials Science” a large number of textbooks, teaching aids, guidelines and manuals on laboratory work and course design, as well as collections of scientific papers, articles and monographs on the main areas of research work were published.The historical digression presented in this article gives an idea of the scientific potential of the department accumulated over many years, which can serve as a reliable basis for further development of new scientific directions.

Innovative in-place repair technology for assembles in marine, railway, and road transport, as well as industrial equipment in the Arctic: Practical application

For forty years, serpentine-based tribological compounds have been successfully used in sea and river vessels, on railroads, in agricultural machinery, in a wide range of industrial equipment, as well as in passenger and freight road transport. The article presents only some practical results of using serpentinebased friction geomodifi s in technical equipment that can be used in the development of the Arctic, as well as in ships on the Northern Sea Route.

Innovative in-place repair technology for assembles in marine, railway, and road transport, as well as industrial equipment in the Arctic: Practical application

For forty years, serpentine-based tribological compounds have been successfully used in sea and river vessels, on railroads, in agricultural machinery, in a wide range of industrial equipment, as well as in passenger and freight road transport. The article presents only some practical results of using serpentinebased friction geomodifi s in technical equipment that can be used in the development of the Arctic, as well as in ships on the Northern Sea Route.

Effects of hydroxyapatite content on cytotoxicity, bioactivity and strength of metakaolin/hydroxyapatite composites

The development of new materials is a critical challenge in advancing bone repair technology. Nowadays, the use of high strength geopolymers is extended to various fields, including biomedical research. This study investigates the influence of hydroxyapatite (HAp) content on the in vitro properties and characteristics of the metakaolin/HAp (MK/HAp) composites for potential application as bone substitutes. The MK/HAp composites with varying HAp contents were fabricated and subjected to cytotoxicity, bioactivity, physical and mechanical testing. PrestoBlue assay results confirmed acceptable osteoblast cell compatibility for all composites, with cell viability increases with increasing HAp content. Simulated body fluid (SBF) immersion demonstrated enhanced bioactivity and bone-like apatite formation on the composite surfaces with increasing HAp content. The compressive strength of the composite decreased mainly due to the reduced amount of silica and alumina contents and the increased porosity with higher HAp. Based on the present results, the relationship between bioactivity and strength with variations in HAp content indicates a promising composite. The HAp content of the MK/HAp composites for a bone substitute material should be 50% or higher to match the apatite formation and strength of specific human bones.

Toward Circular Energy: Exploring Direct Regeneration for Lithium-Ion Battery Sustainability.

Lithium-ion batteries (LIBs) are rapidly developing into attractive energy storage technologies. As LIBs gradually enter retirement, their sustainability is starting to come into focus. The utilization of recycled spent LIBs as raw materials for battery manufacturing is imperative for resource and environmental sustainability. The sustainability of spent LIBs depends on the recycling process, whereby the cycling of battery materials must be maximized while minimizing waste emissions and energy consumption. Although LIB recycling technologies (hydrometallurgy and pyrometallurgy) have been commercialized on a large scale, they have unavoidable limitations. They are incompatible with circular economy principles because they require toxic chemicals, emit hazardous substances, and consume large amounts of energy. The direct regeneration of degraded electrode materials from spent LIBs is a viable alternative to traditional recycling technologies and is a nondestructive repair technology. Furthermore, direct regeneration offers advantages such as maximization of the value of recycled electrode materials, use of sustainable, nontoxic reagents, high potential profitability, and significant application potential. Therefore, this review aims to investigate the state-of-the-art direct LIB regeneration technologies that can be extended to large-scale applications.

Optimizing lunar regolith for vat polymerization and sintering: pre-processing & mineral composition impact

Lunar regolith is the most abundant resource on the lunar surface, which can be used for in-situ fabrication and repair technologies. Vat photopolymerization-based additive manufacturing is among the most promising techniques, capable of producing precise ceramic parts of complex shapes from the lunar regolith feedstock for the needs of future crewed exploration missions to the Moon. One of the under-studied aspects of additive manufacturing with lunar regolith is the pre-and post-treatment procedures, which would ensure optimal energy and material consumption and the best printing performance. The goal of the present article was to define the influence of the mineral composition of lunar regolith simulants and the parameters of their pre-processing on the properties of sintered regolith ceramics. It was found that the highland regolith could be sintered to higher relative density compared to the mare regolith. The optimal sintering temperature was determined to be 1150 °C for both types of lunar regolith. An optimal mineral and fractional composition for the regolith feedstock was determined based on the trade-off analysis between lunar regolith sinterability and its printability via vat photopolymerization-based additive manufacturing. Vat-polymerization was performed to produce complex-shaped ceramic parts, yielding 95 % of relative density and a mean ultimate flexural strength of 106 ± 5 MPa, confirming the proposed trade-off point.

Optimized Biomanufacturing for Treatment of Volumetric Muscle Loss Enables Physiomimetic Recovery.

Volumetric muscle loss (VML) injuries are defined by loss of sufficient skeletal muscle to produce persistent deficits in muscle form and function, with devastating lifelong consequences to both soldiers and civilians. There are currently no satisfactory treatments for VML injuries. The work described herein details the implementation of a fully enclosed bioreactor environment (FEBE) system that efficiently interfaces with our existing automated bioprinting and advanced biomanufacturing methods for cell deposition on sheet-based scaffolds for our previously described tissue-engineered muscle repair (TEMR) technology platform. Briefly, the TEMR technology consists of a porcine bladder acellular matrix seeded with skeletal muscle progenitor cells and preconditioned via 10% uniaxial cyclic stretch in a bioreactor. Overall, TEMR implantation in an established rat tibialis anterior (TA) VML injury model can result in 60 to ∼90% functional recovery. However, our original study documented >50% failure rate. That is, more than half of the implanted TEMR constructs produced no functional improvement beyond no treatment/repair. The high failure rate was attributed to the untoward mechanical disruption of TEMR during surgical implantation. In a follow-up study, adjustments were made to the geometry of both the VML injury and the TEMR construct, and the "nonresponder" group was reduced from over half the TEMR-treated animals to just 33%. Nonetheless, additional improvement is needed for clinical applicability. The main objectives of the current study were twofold: (1) explore the use of advanced biomanufacturing methods (i.e., FEBE bioreactor) to further improve TEMR reliability (i.e., increase functional response rate), (2) determine if previously established bioprinting methods, when coupled to the customized FEBE system would further improve the rate, magnitude or amplitude of functional outcomes following TEMR implantation in the same rat TA VML injury model. The current study demonstrates the unequivocal benefits of a customized bioreactor system that reduces manipulation of TEMR during cell seeding and maturation via bioprinting while simultaneously maximizing TEMR stability throughout the biofabrication process. This new biomanufacturing strategy not only accelerated the rate of functional recovery, but also eliminated all TEMR failures. In addition, implementation of bioprinting resulted in more physiomimetic skeletal muscle characteristics of repaired muscle tissue.