Probing the Anti-Corrosion Behavior of X65 Steel Underwater FSW Joint in Simulated Seawater

To detect the corrosion resistance of a friction stud welding (FSW) joint in simulated seawater (a 3.5 wt% NaCl solution), the pulse electrochemical deposition method was used for electroplating Ni coating with different duty ratios (50%, 80%, and 100%) on the surface of FSW joint. The microstructure and surface structure of the coating were observed by micro-spectroscopy and other characterization methods. The corrosion behavior of the coating was analyzed by means of macroscopic electrochemical testing. The local corrosion law of joint surface and coating surface defects were innovatively explored by using micro-zone electrochemical scanning system. The coating characterization results showed that, as the duty ratio continues to increase, the coating surface becomes denser and smoother, and the corrosion products such as Fe2O3, Fe3O4, and FeOOH are generated. The results of macroscopic electrochemical experiment indicated that the coating with 100% duty ratio has the lowest corrosion current density and the maximum polarization resistance. The scanning vibrating electrode technique results showed that the corrosion current density in the defect area is higher than that in the coating area, and the maximum corrosion current density decreases with the increase of duty ratio. The localized electrochemical impedance spectroscopy results indicated that the localized impedance at the welded zone was the largest, and with the increase of the pulse duty ratio, the impedance diffusion in the defect area was decreasing.

Is It Possible to Perform Fifth Carpometacarpal Joint Arthroscopy? Cadaveric Study on Its Feasibility, Safety, and Potential Hazards in Portal Creation

Background Fifth carpometacarpal joint (CMCJ) fracture dislocation is a relatively rare injury and most will require operative treatment because of its unstable nature. Improper reduction and fixation lead to joint surface destruction, pain, and reduced grasping power. Intra-articular fragment reduction is often obscured by dorsally displaced ulnar fragment. Therefore, fifth CMCJ arthroscopy can be advantageous in assisting intra-articular fragment reduction. However, there is no detailed description of the portal landmarks or portals' relationship with adjacent important structures in the literature. Purposes To explore the feasibility and safety of fifth CMCJ arthroscopy, locations of the portals are examined in cadaveric hand specimens. Their proximity to important anatomical structures such as dorsal cutaneous branch of ulnar nerve (DCBUN), ring finger and little finger extensor digitorum communis (EDC), and extensor digiti minimi (EDM) is measured. Methods Fifth CMCJ arthroscopy is performed on 11 cadaveric hand specimens by specialist-level surgeon. The portals are marked and portal positions are further confirmed under the fluoroscopy. Then the cadaveric specimens were undergone anatomical dissection by specialist-level surgeon. During dissection, the spatial relationship between the portal positions and DCBUN, EDC to ring finger and little finger, and EDM is identified. The distance between the portals and the above important structures was measured in millimeters. Results DCBUN was consistently found between fourth metacarpohamate (4-MH) and fifth metacarpohamate (5-MH) portals, with it being closer to the latter (mean distance, 2.03 mm; range, 0–4.43 mm; standard deviation [SD], 1.09 mm). The closest tendon for 4-MH portal is ring finger EDC (mean distance, 2.65 mm; range, 0–5.89 mm; SD, 1.78 mm), while 5-MH portal and accessory portal were closest to EDC (mean distance, 1.88 mm; range, 0–3.69 mm; SD, 1.25 mm) and EDM (mean distance, 7.79 mm; range, 6.63–10.72 mm; SD, 1.49 mm), respectively. During the process of specimen dissection, we found no damage to the above structures after portal introduction. Conclusion The above findings support the use of fifth CMCJ arthroscopy, which can be used for assisted reduction in fifth metacarpal base fracture dislocation and hamate body fracture. Gentle soft tissue spreading technique during portal creation prevents injury to the important structure surrounding the portals. Level of evidence This is a Level V study.

Analysis of Reservoir Seismic Law Based on Three-Dimensional Morphological Characteristics of Joint Surface Related to Listric Fault

Since water storage, earthquakes occurred in Badong County, Hubei Province, accounted for as much as one-third of the strong earthquakes in the Three Gorges Reservoir area. For example, the MS5.1 earthquake occurred in December 2013 near the Gaoqiao fault in Badong County. The earthquake time, magnitude, and location analysis showed that reservoir earthquakes in this area exhibited some characteristics, such as periodicity, migration, and deep extension. Based on the regional stratum lithology and structural characteristics, this paper designed a curved joint on a small scale to simulate the structural morphology of the Gaoqiao fault and carried out triaxial compression tests under different immersion times to analyze the morphological parameters of the joint surface. The results showed that topological parameters such as root mean square height (Sq), arithmetic average height (Sa), reverse load area ratio (Smc), and minimum autocorrelation length (Sal) could effectively characterize the degree of damage and deterioration of curved joints. The test privides a reference for analyzing the evolution law of the seismic characteristics of the reservoir.

Study on the Physical Properties and Joint Evolution Characteristics of Three-Dimensional Reconstructed Coal

There are various complex joints (fissures), laminae, and other soft structural surfaces in the roadway enclosure, and the existence of these soft structural surfaces seriously affects the stability of the roadway enclosure. In order to study the mechanical properties of the coal body and the development of joints during coal fracture, this paper establishes a three-dimensional model of the fracture structure of the coal body based on CT scanning and three-dimensional reconstruction technology. On this basis, a 3D numerical model of the equivalent nodal coal body is constructed, uniaxial compression simulation analysis is performed, and the joint evolution development law of the coal sample is studied by the built-in joint monitoring program of PFC3D. The results show that the larger the effective joint area and larger the joint size inside the coal sample, the smaller the compressive strength of the coal sample. The increase of joint size and joint surface area increased the ductility and stress-strain curve multipeak phenomenon of the coal sample to some extent. During the rupture of the coal sample, the changes of each phase of the statistical curve of joint number and the phases of the stress-strain curve of the coal sample are compatible.

Malunion fracture of supracondylar femur sinistra with post traumatic arthritis and stiffness at genu sinistra: a case report

Post-traumatic osteoarthritis could emerge immediately after an injury or one year after a bone fracture, ligament injury, and meniscal tears. In this case report, we present a 30 years old male who previously suffered from joint injury and thus lost the ability to flexion. This patient has already under went internal bone implantation surgery involving the implantation but was removed due to pain, and there was protruding implant on the left knee. On physical examination, there was varus deformity with flexion ranged between 0-5°. On radiological examination, malunion and narrowing of the joint surface were, as shown, clinically inhibit the flexion of the knee. We diagnose the patient with malunion supracondylar femur sinistra and post traumatic osteoarthritis genu sinistra. Liberation procedure (soft tissues release) and osteotomy of the distal femur were performed on this patient. On post-op radiological examination, the implant successfully widens the joint surface and holds the fracture fragment after it was reduced. The joint was immediately mobilize using the machine. It was shown that in a relatively short period, the range of motion could reach 90°. Three months post-op, evaluation was done, and it was clearly shown that the range of motion had not decreased.

Features of morphological changes in articular tissues in vascular diseases of the lower extremities

Background. Big epidemiological studies have revealed a link between osteoarthritis and some cardiovascular diseases such as coronary heart disease, heart failure, cerebral circulation disorders, vascular diseases and diabetes mellitus. Objective. Determination of the features of morphological changes in the synovial membrane of the joint, articular cartilage and subchondral bone in patients with cardiovascular diseases. Methods. Histological studies of articular tissues of 30 amputated lower extremities in persons with vascular diseases of the lower extremities were performed. Results. In all samples of the capsule of the knee joint, gross violations of the microcirculatory canal and histological changes of osteoarthritis and subchondral osteoporosis were revealed. At the same time, the revealed changes in the articular cartilage and subchondral bone were more pronounced in the patellar, which in the knee joint carries a negligible functional load, but receives blood supply only from the vessels of the articular capsule than in the joint surface of tibia, carrying the lion's share of the functional load on the knee joint, but receiving blood supply from the posterior tibial artery. Conclusion. The revealed features of morphological changes in articular tissues in vascular diseases of the lower extremities indicate that these diseases play an important role in the development of osteoarthritis and are more significant than the functional load on the joint. Further studies of the features of morphological changes in articular tissues in the samples of various contingents of persons are needed.

Studying phase formation of 12Х18Н10Т alloy and copper after friction welding

The technology of joining alloy 12X18H10T and copper has been studied. The use of friction welding is proposed. Modern development of technology requires the use of new technologies and materials. Despite the increase in the use of composite materials, and especially on the basis of the polymer matrix, metal alloys remain indispensable. Due to their physical and mechanical properties, metal-based alloys are used in rocket and space technology, mechanical engineering, and other industries. Goal. The aim of this work is the reason for the decrease in the mechanical properties of the connection 12Х18Н10Т – М1, which were obtained under suboptimal conditions. Friction welding was developed in early 1956 in the USSR. Since the 1960s, other countries have also begun to develop friction welding. This tool is a type of pressure welding, during which the metal is heated by friction of one of the parts of the product. At the end of the process, the final connection takes place. This type of welding is used in aircraft construction, rocketry, machine building, etc. In Ukraine, research in this direction is conducted at the Eugene Paton Institute of Electric Welding. The parameters of the friction welding technological process are considered. Results. The samples of welded joints 12Kh18N10T + M1 were studied. The following methods were used: mechanical tests; metallographic and electro-microscopic studies; hardness measurements; micro-X-ray spectral study. Originality. Welding joints with low strength were investigated; they were obtained for the following parameters: relative rotation speed 0.4 m/s, pressure during heating 80 MPa, pressure during forging 80 MPa, upset value 9 * 10-3 m samples with low strength varied in the deformed layer of steel from the joint surface to the base metal from 3240 MPa to 2450 MPa; in a deformed copper layer from 1020 MPa to 690 MPa. On samples that had high strength, the microhardness varied on the steel side from 2260 MPa in the contact surface to 2160 MPa, and in copper from 590 MPa to 460 MPa. Fig. 1 shows the microstructure of the deformed zones of the welded joint 12X18H10T, obtained according to the optimal parameters. Practical value. The reason for the decrease in the mechanical properties of the 12Х18Н10Т – М1 joint was established.