Evaluation of early results of patients with permanent peacemakers implantation at Bai Chay Hospital from 2016 to 2020

Objectives: Review the results of pacing and some early complications of patients Who implanted pacemaker at Bai Chay Hospital from 2016 to 2020. Subjects and research methods: A descriptively prospective study longitudinal follow-up study on 31 bradyarrhythmia patients who were permanently paced at Bai Chay Hospital from 2016 to October 2020. Results: After implantation of pacemaker, the rate of symptoms improved markedly, the change was statistically significant with p = 0.0001. Medium heart rate before and after implantation (47.84 ± 7.712 with 65.61 ± 4.425, 95%CI: 17.77 ± 7.173, p = 0.000). Change in QRS width after implantation (153.52 ± 11,963ms vs 91.81 ± 10,882ms, 95%CI 61.71 ± 12,947, p = 0.000). Pacing threshold changed after 6 months (0.68 ± 0.146V; 0.73 ± 0.149; p=0.001). Received R wave and electrode wire impedance did not changing after 6 months of follow-up. The rate of complications right after the procedure accounted for a total of 6.45%. The rate of complications after 6 months of follow-up accounted for 6.45%. Complications were all minor complications and were well managed. The successful rate of the procedure reached 100%, the pacing parameter was assessed as good, accounting for 70.97%. Conclusion: The method is considered effectively in the symptom improvement, safety, low complication rate and should be applied and deployed for patients with bradyarrhythmias with indications for permanent pacemaker implantation.

Quality Criteria for G3Si1 and G4Si1 Electrode Wires

The article presents test results concerning the quality of ISO 14341-A-G3Si1 and G4Si1 electrode wires based on electrode wire-related quality criteria in accordance with the requirements specified in the PN-EN ISO 14341 and PN-EN ISO 544 standards. The article discusses the critical defects of the wires (non-conformities with standard requirements) as well as defects not covered by the requirements of the standards, yet decisive as regards the assessment of electrode wires by the user.

Consumable electrode – additional filler wire arc interaction control under surfacing (DE-GMAW)

Introduction. Arc surfacing through feeding an additional filler wire heated by an additional arc burning between the filler wire and the electrode wire is considered. Under the conditions of such surfacing, the minimization of the input of the remelted substrate metal into the weld metal is studied. The research objectives are to examine the conditions providing self-regulation of this advanced arc surfacing process, and to evaluate control capabilities of the heat impact power on the metal and on the weld metal flow.Materials and Methods. In solving a wide range of welding and surfacing tasks, it is advisable to use engineering analysis methods based on physicomathematical modeling of processes and phenomena. These include:self-regulation of the arc process under joint melting of the electrode and the filler wires;assessment of the possibilities to control the heat impact power on the metal and on the weld metal flow during the formation of the weld The features of the arc surfacing of anticorrosive chromium-nickel steels on low-alloy steel are considered in the paper.Results. New mathematical dependences are proposed that describe physical phenomena under surfacing with an arc interaction between the electrode and filler wire. A physicomathematical model of the joint melting of the electrode and filler wire is developed. It provides determining the values of the control parameters. In addition, you can find out how much heat affects the substrate from:heat release in the main arc,droplet flows of the weld electrode and filler metal,arc plasmaDiscussion and Conclusions. It is established how the current and the lengths of the main and additional arcs are affected by the supply voltages. The feed rate of the electrode and filler wire with a diameter of 1.6 mm and 1.2 mm made of Inconel 625 alloy is determined. It is shown what thermal effect the substrate undergoes in this case. It is noted that due to the larger value of the main arc current, the diameter of the electrode wire should be larger than that of the filler wire. The heat flow in the substrate is created mainly by the flow of the weld metal droplets.

On the solution of the problem of synthesis of the control system for the process of dosed feed of electrode wire for arc welding equipment

Goal. Refinement of the methodology for the development of an effective control system for an electric drive with controlled relay-type regulators for organizing a metered feed of an electrode wire using the parameters of the arc process with the possibility of using it in design practice and practice of technological application. Methodology. The proposed method for the mathematical description (mathematical model) of the system of the developed structure electric drive - arc process with current feedback of welding with a variable structure device is based on the theory of automatic control as applied to nonlinear elements, the application of the theory of operational calculus. At the same time, a selection and description of a nonlinear node in the feedback circuit in the form of a relay element with a certain structure and subsequent linearization of this element was made. As an electric motor of the electrode wire feeder, a new development of a specialized valve electric motor is used, which is used in the system with a microprocessor controller. Results. Due to the presence of a substantially nonlinear link, the calculation of the valve electric drive system – the arc process can be found on the basis of a system of nonlinear differential equations, which is practically impossible for practical application. In this work, these complications are overcome on the basis of a rational choice of the description of the nonlinear link, its harmonic linearization and obtaining on this basis a mathematical description of the system, from which, using the methodology of operational calculus, the relations necessary for calculating the parameters of the system are determined in analytical form. Originality. The problem of calculating a rather complex problem of mathematical description of the valve electric drive system – a technological link in the form of an arc process with a substantially nonlinear link in the feedback circuit in the work is solved with the effective use of a set of methodological methods, which include as a means of representing individual links, including nonlinear links selected simplifications and solutions of the obtained differential equations using original methods of operational calculus. The proposed method (mathematical model) is tested in two directions – oscillography of a real system, as well as system simulation. Practical significance. Using the developed methods for describing the control system, it is possible to calculate its characteristics and, on their basis, select the parameters for setting the electric drive controller, which allows, without additional experimental research, to obtain the necessary character of the transfer of electrode metal, and, consequently, the quality of the result of the arc process.

Study of weld form and weld bead in bottom position at semi-automatic underwater wet welding

Some features of underwater mechanized and automatic wet welding with pulse feed of the electrode wire are considered. The conditions for experimental research to identify the parameters of forming of the weld metal at different parameters of pulse feed of the electrode wire are described. Regression equations describing the dependences of the size of the roll on the parameters of pulse feed and contour plots and response surfaces of the marked dependences are presented.