PLANNING AND SCHEDULE OF MAINTENANCE WORKS FOR INJECTION MACHINES

Keeping the equipment and machinery in working order is a very important activity in the field of industrial production, being specific to the maintenance department within an enterprise. Ensuring an optimal in operation of the manufacturing systems is closely related to the prevention of defects, an action that must be found in a planning and scheduling of preventive-planned maintenance works. In the paper, in addition to the introductory part on the main objectives and implementation of the maintenance system and maintenance-specific operations, a case study is conducted for the planning and organization of maintenance in a company equipped with plastic injection machines. The main stages developed consisted in elaborating the maintenance plan, establishing the optimal moment for replacing the machine tools, choosing the optimal type of machine tool and establishing the elements of random wear of the machine tools. It is concluded that the optimal type of injection molding machine that will be chosen to replace the T10 injection molding machine is T14, because it has a minimum average cost of acquisition, maintenance and repair, respectively 42.286 UV.

Treatment of COVID-19 disease in pregnancy and breastfeeding

The physiological and anatomical clinical characteristics of pregnant women make them susceptible to complications caused by coronavirus disease (COVID-19). Increased coagulation and risk of thromboembolic phenomena are common during pregnancy; they are further enhanced when associated with a thrombogenic pathology such as in COVID-19. The treatment of COVID-19 is controversial and limited, even for non-pregnant patients. During pregnancy, the options are even more restricted due to the teratogenicity of some drugs and anatomical and physiological difficulties, especially in advanced pregnancy in patients with respiratory failure. Therefore, the focus of treatment for pregnant patients should be centered on isolation, monitoring fetal and maternal vital signs, uterine activity, and general maternal-fetal well-being. The prescription of drugs and management orientation should be based on gestational age and maternal clinical conditions. The optimal type of delivery is guided by obstetric indications and COVID-19 disease severity. Breastfeeding should be encouraged with the use of masks and hand hygiene. The treatment of pregnant women with COVID-19 brings important peculiarities that should be considered in order to make better decisions for preserving the health of the mother and fetus.

Processing of two-dimensional velocity fields for reconstructing three-dimensional flow patterns

The paper is concerned with the obtaining three-dimensional velocity fields of a gas or liquid flow based on the available cross-sections of this flow. The descriptions of the main optical methods for studying flows are designed to construct a cross-section of the observed process, but it would be much more informative to obtain information in the visualization not in the cross-section of a volume, but in this volume itself. The paper deals with obtaining three-dimensional flow velocity fields using various approximation methods. The method of estimating the most suitable approximating function is also given. The determination of the optimal type of approximation for the reconstruction of the three-dimensional velocity field was tested on an artificially created vortex.

The application efficiency of precast monolithic frame systems in civil engineering

Introduction. The partial replacement of cast-in-situ concrete with precast concrete in the residential construction sector allows to reduce construction time and cost, increase labour productivity and cut CO2 emissions. Combinations of prefabricated and monolithic elements in precast monolithic frames are presented; they encompass 6 different structural options of precast monolithic frames and 2 types of monolithic frames. The co-authors compare production costs and integrated labor intensity for all frame design options, construction periods per 1,000 m3 of a residential building for various structural options of the frame, and assess potential reduction in carbon dioxide emissions due to a change in the amount of precast reinforced concrete in the building frame structure. Materials and methods. The co-authors have developed a method that employs weighted average to identify the optimal type of a precast monolithic frame. The method takes account of such factors as production costs, integrated labour intensity, construction time and reduction in carbon dioxide gas emissions (in per centum) per 1,000 m3 of the frame structure. Results. The optimal structure of a precast monolithic frame was selected and calculated using weighted average. Weighted average was used to identify the most effective structural frame. The calculation results have shown that ARKOS precast monolithic frame with precast columns is the leader in terms of weighted average; it best suits the construction of a residential building. If we consider each of the selected indicators separately, RECON frame with precast floors is to be selected; however, RECON is inferior to ARKOS in terms of weighted average due to different values of the weight coefficients attached to each of the assessment criteria. Conclusions. The co-authors have proven the efficiency of precast monolithic frame systems in comparison with monolithic frames if applied to construct a residential building. The proposed method was employed to select the optimal type of frame.

Development of a simulation model of a cargo customs complex operation as a link of a logistic supply chain

The main link in the logistics supply chain is the cargo customs complex. It provides customs and logistics services to cargo owners during the export and import of goods, complex services, placement of goods in a customs warehouse and a temporary storage warehouse. To substantiate the choice of the optimal logistics supply chain and optimize the work of the cargo customs complex, it is proposed to use simulation modeling. The model of operation of the logistics chain and the cargo customs complex is presented in a general form. The proposed model is implemented in the GPSS World simulation automation package. Testing the simulation model involved checking its adequacy. Checking the adequacy of the simulation model, which showed the maximum value of the t-statistic of 1.424 with a critical value of 1.85, proved its compliance with the work of a real object. After completing the adequacy check, the simulation error was estimated, which was 3 % with an allowable 5 %, due to the presence of pseudo-random number generators in the simulation model. Thus, the simulation error is insignificant for this study. For the cargo customs complex, an example of the simulation results is given. Based on the results of simulation modeling, it is possible to determine: the optimal type of the logistics supply chain and the optimal structure of the cargo customs complex. A wide range of tasks that the proposed simulation model can solve is presented. Thus, the developed simulation model will make it possible to analyze and improve the modes of operation of the cargo customs complex. In addition, it will allow to get an informed decision regarding the use of a certain type of logistics supply chain

Assessing risks of developing and persistence of infectious process in knee joint replacement

Despite of intensive work on improving endoprosthetic replacement constructions, using minimally invasive techniques, developing methods of prevention for and treatment of periprosthetic joint infection, relapse of infection process can reach up to 52 % after treatment.The aim of the study: to show the importance of identifying the risks of development and recurrence of periprosthetic infection after implantation of a knee joint endoprosthesis. A clinical case of the development of a deep periprosthetic infection in a patient after primary knee replacement and successful treatment of the resulting complication was demonstrated. The analysis of this case of an infectious complication using the proposed prognosis for the development of periprosthetic infection showed that before surgical treatment of the patient, the risk of an infectious process was not assessed, and appropriate preventive and therapeutic measures were not carried out.Materials and methods. In the treatment of developed periprosthetic infection of the knee joint, the author’s algorithm for choosing surgical tactics was used, which allowed to determine the high risk of recurrence of periprosthetic infection, evaluate additional criteria and choose the optimal type of surgical intervention – two-stage revision endoprosthetic, which allowed to stop the infectious process.New was the use of the proposed prognosis for the development of periprosthetic infection and the algorithm for choosing surgical tactics for periprosthetic infection, which make it possible to determine the necessary preventive measures to reduce the risk of an infectious complication and to apply the optimal type of surgical intervention to relieve periprosthetic knee infection.

Perioperative Antibiotic Use in Endoscopic Endonasal Skull Base Surgery

Background Improved evidence-based guidelines on the optimal type and duration of antibiotics for patients undergoing endoscopic endonasal transsphenoidal surgery (EETS) are needed. We analyze the infectious complications among a large cohort of EETS patients undergoing a standardized regimen of cefazolin for 24 hours, followed by cephalexin for 7 days after surgery (clindamycin if penicillin/cephalosporin allergic). Methods A retrospective review of 132 EETS patients from 2018 to 2020 was conducted. Patient, tumor, and surgical characteristics were collected, along with infection rates. Multivariate logistic regression determined the variable(s) independently associated with infectious outcomes. Results Nearly all patients (99%) received postoperative antibiotics with 78% receiving cefazolin, 17% receiving cephalexin, 3% receiving clindamycin, and 2% receiving other antibiotics. Fifty-three patients (40%) had an intraoperative cerebrospinal fluid (CSF) leak, and three patients (2%) developed a postoperative CSF leak requiring surgical repair. Within 30 days, no patients developed meningitis. Five patients (4%) developed sinusitis, two patients (3%) developed pneumonia, and one patient (1%) developed cellulitis at a peripheral intravenous line. Two patients (2%) developed an allergy to cephalexin, requiring conservative management. After adjustment for comorbidities and operative factors, presence of postoperative infectious complications was independently associated with increased LOS (β = 3.7 days; p = 0.001). Conclusion Compared with reported findings in the literature, we report low rates of infectious complications and antibiotic intolerance, despite presence of a heavy burden of comorbidities and high intraoperative CSF leak rates among our cohort. These findings support our standardized 7-day perioperative antibiotic regimen.

Vocational Guidance Work With Schoolchildren is an Integral Part of the Work of a Multi-Profile Accreditation and Simulation Center

Professional orientation is a generalized concept of one of the components of universal human culture, manifested in the form of society's concern for the professional development of the younger generation, support and development of natural talents, as well as a set of special measures to assist a person in professional self-determination and choosing the optimal type of employment, taking into account his needs and opportunities, socio-economic situation in the labor market. Simulation training is one of the brightest forms of vocational guidance work with schoolchildren.