Improving the efficiency of technological preparation of single and small batch production based on simulation modeling

Technological preparation of production is an integral stage of the production process, which is characterized by high complexity, which is largely felt in the conditions of single and small-scale types of production. The effectiveness of technological preparation of production is increased through automation with the use of simulation modeling. The objective of the study is to develop a simulation model that allows you to determine a rational version of the process for processing a batch of parts. The simulation model described in the article allows to analyze the production schedule of the enterprise, build processing routes, evaluate options for using various types of workpieces and technological equipment, determine the acceptable values of cutting conditions, and choose a rational variant of the technological process of processing a batch of parts. The developed simulation model is based on the principles of modular technologies, the part is considered as a combination of individual elementary surfaces. Each elementary surface contains information about the technological processing route, technological equipment and the type of technological equipment used in its manufacture, cutting conditions and the size of the allowance for each processing stage. The rational choice of the technological process is selected on the basis of multicriteria analysis according to three criteria: the value of variable costs, the production time of a batch of parts and the value of the processing error. The analysis of these criteria is made and the parameters that have the greatest impact on their value are determined. The developed classification of surface elements is described: design elements, technological elements, basic elements, as well as a mathematical model based on which the calculation of the values of the criteria for choosing a rational option

Experimental Study of New Design for Orthogonal and Pelton Turbines Using a 3D Printer

В последние годы технология гидроэлектроэнергетики Пико получила значительное развитие. В настоящее время эта технология интегрируется в автономные системы в сельских регионах, которые не имеют доступа к электричеству. Данная работа посвящена лабораторному эксперименту с турбиной Пелтона и ортогональной турбиной. Исследована максимальная производительность, проанализированы эксплуатационные характеристики турбин. Настройка принтера выполнена с помощью программы Cura Ultimaker., в которой используется технология послойного осаждения (FDM - моделирование наплавленного осаждения). Результаты эксперимента показали, что при благоприятных условиях турбина Пелтона показала максимальную производительность.In recent years, Pico hydroelectricity has greatly developed, and its technology is now being integrated into an off- grid more so in the rural regions which do not have access to electricity. This paper is about a laboratory experiment designed and manufactured for both Pelton and orthogonal turbines, to measure the highest performance for rotation, also operational performance characteristic of has been dissected. The printer turbines are done by using Cura Ultimaker program. Where used of layer- by- layer deposition technology (FDM - Fused Deposition Modeling). The results from the experiment indicated that under the best working conditions, the Pelton turbine showed the highest performance

Serum Levels of VEGF-A and Its Receptors in Patients in Different Phases of Hemorrhagic and Ischemic Strokes

Vascular endothelial growth factors (VEGFs) are important regulators of angiogenesis, neuroprotection, and neurogenesis. Studies have indicated the association of VEGF dysregulation with the development of neurodegenerative and cerebrovascular diseases. We studied the changes in serum levels of VEGF-A, VEGFR-1, and VEGFR-2 in patients at various phases of ischemic and hemorrhagic strokes. Quantitative assessment of VEGF-A, VEGFR-1, and VEGFR-2 in serum of patients with hemorrhagic or ischemic stroke was performed by enzyme immunoassay in the hyper-acute (1–24 h from the onset), acute (up to 1–7 days), and early subacute (7 days to 3 months) phases of stroke, and then compared with the control group and each other. Results of our retrospective study demonstrated different levels of VEGF-A and its receptors at various phases of ischemic and hemorrhagic strokes. In ischemic stroke, increased VEGFR-2 level was found in the hyper-acute (p = 0.045) and acute phases (p = 0.024), while elevated VEGF-A and reduced VEGFR-1 levels were revealed in the early subacute phase (p = 0.048 and p = 0.012, respectively). In hemorrhagic stroke, no significant changes in levels of VEGF-A and its receptors were identified in the hyper-acute phase. In the acute and early subacute phases there was an increase in levels of VEGF-A (p p = 0.006, respectively) and VEGFR-2 (p p = 0.012, respectively). Serum levels of VEGF-A and its receptors in patients with hemorrhagic and ischemic stroke indicate different pathogenic pathways depending on the phase of the disease