Ionic Mass Transfer at Point Electrodes Located at Cathode Support Plate in an Electrorefining Cell in Presence of Rectangular Turbulent Promoters

Current density plays a major role in deciding the plant size, current efficiency, and energy consumption in electrorefining cells. In general, operating current density will be 40% of the limiting current density. Forced circulation of the electrolyte in the presence of promoters improves the mass transfer coefficient. In the present study, rectangular turbulence promoters are fitted at the bottom side of the cell to improve the mass transfer coefficient at the cathode support plate. The limiting current density technique is used to measure the mass transfer coefficient. The variables covered in the present study are the effects of flow rate, promoter height, and spacing among the promoters. The electrolyte consists of copper sulfate and sulphuric acid. At a regulated flow rate, the electrolyte is pumped from the recirculation tank to the cell through an intermediate overhead tank. The limiting current density increased with an increasing flow rate in the presence of promoters, and thus the overall mass transfer coefficient on the cathode support plate also improved. With an increase in the flow rate of the electrolyte from 6.67 × 10−6 to 153.33 m3/s, limiting current density increased from 356.8 to 488.8 A/m2 for spacing of 0.30 m, with a promoter height of 0.01 m. However, it is noteworthy that when the promoter height is increased from 0.01 to 0.07 m, the overall mass transfer coefficient is found to increase up to 60%, but with the further increase in the promoter height to 0.30 m the mass transfer coefficient starts to decrease. Therefore, the optimized cell parameters are established in this work. The current sustainable concept of employing rectangular turbulence promoters will bring benefits to any precious metal refining or electrowinning tank house electrolytes.

Dynamic Response and Parametric Studies of Elliptical Blast-Resistant Door with the Combined Structure for Large Vacuum Explosion Containers

In recent years, with the improvement of environmental protection requirements year by year and the continuous expansion of explosive working scale, higher standards have been put forward for explosive working. It is hoped that the sphere of influence of the explosion can be limited to a minimal range. The explosion vessel is driven by such demand. As the explosion vessel’s key component, studying the blast-resistant door in depth is of great significance. This paper introduces a new elliptical blast-resistant door with the combined structure (EBD), mainly welded with an elliptical panel, arc support plate, and triangle support plate. The finite element program AUTODYN was used to calculate the explosion load, and LS-DYNA was used to calculate the blast-resistant door’s dynamic response. The calculation results show that the newly proposed EBD’s blast-resistance capacity is better than that of the traditional structure. To further study the factors that affect the dynamic response of the EBD, a parametric study was carried out on the EBD, mainly analyzing the influence of the vacuum degree in the explosion vessel, the number of explosives, and the diameter ratio of the EBD. The parametric calculation results show that reducing the vacuum degree in the explosion vessel and the number of explosives during explosion working can improve the blast-resistance capacity of the EBD. Based on the analysis of the dynamic response of four kinds of EBD with different diameter ratios under 0.2 atm explosion load, the optimal diameter ratio of the EBD is given.

Significance and Clinical Effect of Anteromedial Support Plate Assisted Reduction and Fixation in The Treatment of Complex Proximal Humeral Fractures

Background There are more and more complex consolidated proximal fractures, and the postoperative effect is not very satisfactory. Therefore, we propose a surgical method and evaluate its effect. Method A total of 77 patients with complicated proximal humeral fractures who underwent surgical treatment in the Affiliated Hospital of Nantong University from June 2015 to January 2019 were collected. Among them, the internodal groove medial support plate assisted reduction and fixation technique and the lateral locking plate were used. A total of 15 cases of complicated proximal humeral fractures were used as the study group, and 62 patients with the same type of proximal humeral fractures treated with traditional reduction methods and internal fixation with lateral locking plates during the same period were used as the control group.The operation time of the two groups; intraoperative blood loss; number of effective intraoperative fluoroscopy; postoperative humeral neck shaft angle loss after reduction; postoperative shoulder joint Constant-Murley score; upper limb function DASH score and postoperative complications were retrospectively reviewed comparative analysis. Results The number of effective intraoperative fluoroscopy was (6.18±1.869) times in the control group, more than (3.93±1.387) times in the study group, and the difference between the two was statistically significant (P<0.05);The operation time of the study group was longer than that of the control group, and the intraoperative blood loss of the study group was more than that of the control group, but the difference between the two was not statistically significant (P>0.05).In the first 1, 3, 6, and 12 months after surgery, in terms of imaging measurement, the loss angle after reduction of the humeral neck shaft angle in the control group and the study group increased with the increase in postoperative time. There was no significant difference in the lost angle after reduction of the humeral neck shaft angle between the two groups at month and 3 months (P>0.05).At the 6th and 12th months after surgery, the lost angle after reduction of the humeral neck shaft angle in the study group was smaller than that in the control group, and the difference between the two groups was statistically significant (P<0.05).For the recovery of shoulder joint function after surgery, the Constant-Murley score of the shoulder joint and the DASH score of upper limb function of the control group and the study group increased with the increase of postoperative time, while the Constant score and DASH score of the two groups were 1 after surgery. There was no significant difference at months, 3 months, 6 months and 12 months (P>0.05). Conclusion The anteromedial support plate assisted reduction of the internodal groove can be used as a single locking plate for the treatment of complex proximal humeral fractures with medial column instability. It is an option when reduction is difficult or it is difficult to maintain stable reduction, which improves the quality of reduction and reduces surgery. Loss of posterior fracture reduction.

Numerical and Experimental Study on Suppression Effect of Acoustic Black Hole on Vibration Transmission of Refrigerator Compressor

The acoustic black hole (ABH) structures have the potential to achieve structural vibration suppression and noise reduction through the effect of the ABH on the concentration and manipulation of flexural waves. In this paper, a new solution is proposed to embed 2-D ABHs on the support plate to suppress the transmission of compressor vibration to the refrigerator body. The vibration and acoustic measurement experiment of the compressor, the support plate and the refrigerator body, and the coherence analysis of the vibration signals and acoustic signal are carried out to determine the influence of the compressor vibration on the vibration of the refrigerator body and the radiation sound of the back wall. The concentration and manipulation effects of 2-D ABH on flexural waves are verified by numerical simulation of flexural wave propagation in the time domain. FEM models of the original support plate and the damping ABH support plate are established to investigate the comprehensive effect of the 2-D ABHs and the damping layers on the vibration characteristics of the support plate through vibration modal and dynamic response analysis. Numerical simulation results show that the 2-D damping ABHs can suppress the vibrations generated by the compressor at specific frequencies in the middle and high-frequency bands from being transmitted to the refrigerator body through the support plate.

Analysis of in-vessel accident progression in VVER1000 NPP during SBO accident with external reactor vessel cooling method

In this study, the MELCOR v1.8.6 code was utilized to perform an analysis of the in-vessel accident progression in VVER1000 reactor during the Station Black-Out (SBO) accident with and without external reactor vessel cooling (ERVC) strategy. The analysis presented the predictions of the main phenomena during the accident such as failure of fuel cladding, collapse of lower core support plate, relocation of core debris to lower plenum and mass of debris components in lower plenum, and provided comparisons between two cases in term of main parameters such as integrity time of reactor and structure components of molten pool. These parameters are very important inputs for further research on the application of external vessel cooling strategy for VVER1000 reactor.

Resent constructions of road bridges’ expansion joints

At present, there are high requirements for materials and construction elements in civil engineering in common. These intentions are fully applicable to such bridge construction elements as expansion joints. The new developed models are needed, in which all the defects and limitations of the previous models are solved and the maximum of operational life is reached. The main types of bridge expansion joints: closed joints, filled-type joints, covered joints. In this article the construction features, advantages and disadvantages of the listed expansion joints are considered. On the basis of the gotten results it is seen that new and developed models of different types expansion joints have better rates in all of considered criteria. It means that these joints have bigger structural reliability and provide longer operational life of the construction. The most effective models of bridge expansion joints are: closed-type joints with metal support plate, filled-type joints with convex V-shaped compensator and covering slab, covered joints with finger slabs and flap hinged rods and springs.

Treatment of posterolateral tibial plateau fractures with a rotational support plate and special pressurizer: technical note and retrospective case series

Background In tibial plateau fractures, the posterolateral segment of the tibia plateau is frequently affected and challenging to treat. Although there are many surgical approaches and fixation methods for the treatment of these fractures, all of these methods have limitations. We designed a new rotational support plate (RSP) and a special pressurizer that can fix the fracture directly via the anterolateral approach. This method is advantageous because it leads to little trauma, involves a simple operation, and has a reliable fixation effect. This study details the technique of treating these fractures with the RSP and special pressurizer and provides the outcomes. Methods From May 2016 to January 2019, the data of 12 patients with posterolateral tibial plateau fractures treated with the RSP and special pressurizer in our hospital were retrospectively analyzed. Postoperative rehabilitation was advised, knee X-rays were taken at follow-ups, and fracture healing, complications, and knee range of motion were assessed. The Hospital for Special Surgery (HSS) knee score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were used to evaluate knee function at the last follow-up. Results The average follow-up time of all patients was 16.5 months (range, 12–25 months). The average bony union time was 3.2 months (range, 3–4.5 months). At the last follow-up, the average knee range of motion was 138° (range, 107–145°). The average HSS score was 91 (range, 64–98). The average KOOS Symptoms score was 90 (range, 75–96). The average KOOS Pain score was 91 (range, 72–97). The average KOOS ADL score was 91 (range, 74–97). The average KOOS sport/recreation score was 83 (range, 70–90). The average KOOS QOL score was 88 (range, 69–93). Skin necrosis, incision infections, and fixation failure did not occur during the follow-up period. Conclusions With our newly designed RSP and special pressurizer, posterolateral tibial plateau fractures can be easily and effectively reduced and fixed through the anterolateral approach, which serves as a novel treatment for posterolateral tibial plateau fractures.

The Fouling Behavior of Steam Generator Tube at Different Positions in the High-Temperature Water

The fouling behavior of a steam generator (SG) tube was investigated at different positions after 500 h of immersion in high-temperature water. A triple-layer structure of fouling appeared at both the crevice position and the free span position, namely, the large, dispersedly distributed deposition layer on the top; the small and faceted outer layer; and the relatively continuous inner layer. There was no obvious positional effect on the thickness of the inner layer. However, in the crevice position, the density of the deposited particle and the thickness of the outer layer was much higher than those of the free span position. The tube support plate (TSP) made of 410 stainless steel contributed significantly to the fouling behavior of the SG tube in the crevice between the SG tube and the TSP.

Treatment of Posterolateral Tibial Plateau Fractures With a Rotational Support Plate and Special Pressurizer: a Technical Note and 12 Cases

Background: Posterolateral tibial plateau fractures are uncommon fractures and challenging to treat. Although there are many surgical approaches and fixation methods for the treatment of these fractures, all of these methods have limitations. We designed a new rotational support plate (RSP) and a special pressurizer that can fix the fracture directly via the anterolateral approach. This method is advantageous because it leads to little trauma, involves a simple operation and has a reliable fixation effect. This study details the technique of treating these fractures with the RSP and special pressurizer and provides the outcomes.Methods: From May 2016 to January 2019, the data of 12 patients with posterolateral tibial plateau fractures treated with the RSP and special pressurizer in our hospital were retrospectively analysed. Postoperative rehabilitation was advised, knee X-rays were taken at follow-ups, and fracture healing, complications, and knee range of motion were assessed. The Hospital for Special Surgery (HSS) knee score was used to evaluate knee function at the last follow-up.Results: The average follow-up time of all patients was 16.5 months (range, 12-25 months). The average bony union time was 3.2 months (range, 3-4.5 months). At the last follow-up, the average knee range of motion was 138° (range, 107°-145°). The average HSS score was 91 (range, 64-98). Skin necrosis, incision infections, and fixation failure did not occur during the follow-up period.Conclusions: With our newly designed RSP and special pressurizer, posterolateral tibial plateau fractures can be easily and effectively reduced and fixed through the anterolateral approach, which serves as a novel treatment for posterolateral tibial plateau fractures.

Development and Testing of a High-Frequency Dynamometer for High-Speed Milling Process

Cutting forces are strongly associated with the mechanics of the cutting process. Hence, machining forces measurements are very important to investigate the machining process, and numerous methods of cutting forces measurements have been applied. Nowadays, a dynamometer is the most popular tool for cutting forces measurements. However, the natural frequency of a dynamometer has a direct impact on the accuracy of measured cutting forces in the machining process. Therefore, few dynamometers are appropriate and reliable to measure the cutting forces at high frequencies. In this work, a new strain-gauge-based dynamometer (SGBD) with a special structure was designed, manufactured, and put to the test to ensure the measurement of high-frequency dynamic forces in the milling process. The main structure of the SGBD is symmetrical and mainly consists of a center quadrangular prism surrounded by four force sensing elastic elements, an upper support plate, and a lower support plate. The dynamic identification test was conducted and indicated that the SGBD′s natural frequency could be stabilized at a high value of 9.15 kHz. To automatically obtain the milling force data with a computer during high rotational speed milling, a data acquisition system was devised for the dynamometer. To reduce the effects of cross-sensitivity and acting point of force, an innovative model based on a conversion matrix was established for the dynamometer. Furthermore, the cutting tests were conducted at high rotational speeds (10,000–18,000 rpm), and it was found that the difference of cutting forces between the SGBD and a Kistler dynamometer are 2.3–5.8% in the X direction and 3.5–8.8% in the Y direction. The experimental findings disclosed that the new kind of dynamometer is reliably for the measurement of high-frequency dynamic forces in milling at high rotational speeds.