Вплив електролітично абсорбованого сталлю водню на параметри сигналів магнетоакустичної емісії

This paper presents preliminary results of study on the applicability of magnetoacoustic emission (MAE) method as a tool for sensing the presence of electrolytically absorbed hydrogen in low carbon steel. It is clearly presented that for the employed laboratory settings a MAE signal parameter, which is the sum of amplitudes of MAE signal impulses, is strongly dependent on the presence of hydrogen in the bulk of the material. It is noted that for the low cathodic current there is a delay in time required, probably, for the removal of the corrosion products from the steel surface and providing the conditions for the sufficient amount of hydrogen to be absorbed by the near-the-surface volume of the sample. The results are shortly discussed regarding the issues connected to the applicability of MAE method for nondestructive evaluation (NDE) of hydrogen absorbed by structural materials.Наведено попередні результати досліджень щодо можливості використання методу мегнетоакустичної емісії (МАЕ) для виявлення водню електролітично абсорбованого низьковуглецевою сталлю. Наведені результати переконливо свідчать, що за зазначених умов проведення експерименту параметр сигналу МАЕ, яким є сума амплітуд імпульсів МАЕ, дуже залежить від наявності водню в об’ємі матеріалу. Зазначено, що для низьких катодних струмів спостерігається затримка в часі, необхідна, вірогідно, для відновлення продуктів корозії на поверхні сталі та забезпечення умов для абсорбування достатньої кількості водню приповерхневими шарами металу. Результати коротко обговорені з огляду на перспективність застосування методу МАЕ як засобу неруйнівного контролю водню абсорбованого конструкційними матеріалами

Вплив деформації на параметри магнетоакустичних сигналів

This paper presents results on the study of the effect of elastic and plastic deformation of low-carbon steel on magnetoacoustic emission (MAE) performed with the measuring system MAE-1L. Generally, the observed tendencies of reduction of MAE with deformation of iron-based alloys confirm those published in the literature. The reproducibility of measurements in the ealstic region is very high. As to the plastic region it demands further investigations. These measurements confirmed the perspectiveness of the method MAE for nondestructive evaluation (NDE) of plastically damaged parts of operated equipment or structures. MAE-1L system exhibited an appropriate service performance.Наведено результати досліджень впливу пружної та пластичної деформацій низьковуглецевої сталі на мегнетоакустичну емісію (МАЕ) із використанням вимірювальної системи MAE-1L. Виявлені тенденції зниження МАЕ із деформуванням сплавів на основі заліза загалом збігаються із опублікованими даними. Відтворюваність вимірювань на ділянці пружних деформацій є дуже висока. Щодо пластичної ділянки, необхідні подальші дослідження. Наведені результати підтверджують перспективність методу МАЕ для неруйнівного контролю ділянок діючого обладнання та споруд, які зазнали пластичного деформування. Система МАЕ-1L продемонструвала належну працездатність

Characteristics of the Respiratory System Status in Patients with Liver Cirrhosis and the Dependence of its Syntropic Lesions on the Severity of the Disease due to C. G. Child – R. N. Pugh Class

Introduction. Today we know, that the course of liver cirrhosis (LC) depends on a number of factors: the nervous and humoral regulation, the proportion of cells, that form the sinusoidal blood flow, neurotransmitters of the autonomic nervous system and other features, that ensure the normal course of the physiological processes and portal pressure maintenance. The result of their equilibrium disorder is the formation of collateral blood flow, esophageal varices, often associated with portal gastro- gantry, entero-, colopathy, splenomegaly, ascites. Changes ofthe blood circulation, accompanying LC, is the basis not only for portal hypertension and its characteristic complications, but also for blood flow disorders, practically, in all organs, including the lungs, with the appearance of the severe pathological changes there, which have, in this case, the causal connection with the degree of pressure increase in the liver portal system. Assessment of the respiratory system status in cirrhotic patients and the dependence of the syntropic disorders on the severity of the disease would optimize the assistance for this large group of patients, but until now this aspect of the problem has not been studied. Purpose of the study. To describe the status of the respiratory system in patients with liver cirrhosis and the dependence of its syntropic lesions on the severity of the disease due to C. G. Child – R. N. Pugh class. Materials and research methods. In a randomized way with preliminary stratification by the presence of respiratory dysfunction, caused by birth defects, hereditary diseases of respiratory system, infectious, autoimmune, allergic, neoplastic, toxic and occupational factors, identified as syntropic, we have involved into the study 93 cirrhotic patients (45.4 % of all surveyed persons [29 women (31.2 %) and 64 men (68.8 %) aged 27 to 73 years, the most able-bodied population category]) and divided them by the severity classes of LC (criteria of C. G. Child – R. N. Pugh). To achieve the aim of the study all the patients were examined using clinical-laboratory and instrumental methods. Was conducted a clinical review, was determined the arterial blood oxygen saturation in standing and lying position, using pulse oxymetry, were calculated some indices of cardiovascular functioning (heart rate, pulse blood pressure, medium dynamic pressure, peripheral resistance, minute volume of blood), the study of blood gas composition of the venous blood and alveolar-arterial gradient for oxygen, spirometry (determination of lung capacity, respiratory volume, minute volume of breath, forced vital capacity, forced expiratory volume in 1 minute, Tiffno index), electrocardiography and echocardiography, was calculated the average pressure in the pulmonary artery, followed by statistical processing of the results. According to the results of our study can be observed the tendency of negative dynamics of respiratory failure in cirrhotic patients, depending on the severity of the disease by the criteria of C. G. Child – R. N. Pugh. All the patients of the experimental group showed the signs of increasing dyspnea with acrocyanosis and the appearance of “spider veins”, symptoms of hypoxemia, more expressed in a lying position, increased minute volume of blood, that deepens it, because of the reduced transit time of blood, and, respectively, the gas exchange through the expanded lung capillaries. Intense reduction of the partial pressure of CO2 indices, O2 partial pressure, blood oxygen saturation, total CO2 level, free and bound O2 levels, compared with the reference rates (p < 0.05), confirm the presence of hypoxemia, due to disorders of ventilation-perfusion relationships and formation of arterio-venous shunts. Conducted instrumental examination revealed the nature of the restrictive type of dyspnea and deny the signs of pulmonary hypertension in these patients. Conclusions. Among the diseases of the respiratory system 54.6 % of cirrhotic patients had concomitant lesions. The incidence of diffuse pneumofibrosis syndrome was 45.4 % and was significantly (p < 0.05) raising with the increase of the disease severity according to C. G. Child – R. N. Pugh and therefore, has common cause and/or pathogenic mechanisms with it, which makes it a syntropic hepato-pulmonary syndrome. In patients with liver cirrhosis and syntropic hepato-pulmonary syndrome the indices of oxygen saturation of capillary and venous blood and its gas composition were significantly lower (p < 0.05) compared with the reference rates, and its severity, assessed by the results of clinical-laboratory and instrumental survey of respiratory system, has directly proportional dependence on the class of liver cirrhosis by C. G. Child – R. N. Pugh – the heavier liver damage, the more severe dyspnea, lung ventilation function violations of restrictive type with hypoxemia and blood gas composition disorders, with reduced ability of hemoglobin to bind and also carry oxygen and more pronounced formation of arterio-venous shunts

THE ESTIMATION OF DEVELOPMENT SELF -CONSISTENT DAMAGES OF SLIMY STEEL CONSTRUCTIONS

The procedure for testing the prismatic steel specimens of heavy constructions to build the kinetic diagrams of fatigue fracture is described in the paper. The kinetic diagrams obtained have been approximated by analytical dependences with unknown parameters, which were found using least squares method

ОЦІНКА РОЗВИТКУ ВТОМНОГО РУЙНУВАННЯ В’ЯЗКИХ КОНСТРУКЦІЙНИХ СТАЛЕЙ

The procedure for testing the prismatic steel specimens of heavy constructions to build the kinetic diagrams of fatigue fracture is described in the paper. The kinetic diagrams obtained have been approximated by analytical dependences with unknown parameters, which were found using least squares method.В работе описано методику испытаний призматических образцов стали крупногабаритных конструкций для построения кинетических диаграмм усталостного разрушения этих материалов. Полученные кинетические диаграммы аппроксимировано аналитическими зависимостями с неизвестными параметрами, найденными методом наименьших квадратов.В роботі описано методику випробувань призматичних зразків сталі великогабаритних конструкцій для побудови кінетичних діаграм втомного руйнування цих матеріалів. Отримані кінетичні діаграми апроксимовано аналітичними залежностями із невідомими параметрами, які знайдено методом найменших квадратів

Технічні засоби для діагностики феромагнетних матеріалів методом магнетоакустичної емісії

A promising method for technical diagnostics of materials which employs the signals of magnetoelastic acoustic emission (MAE) has been described. The results of the numerical modeling of the parameters of the U-shaped electric magnet designed for excitation of the alternating magnetic field that would produce MAE signals in ferromagnetic materials are presented. The principles of a PC-operated measuring system designed for MAE signals acquisition, processing and logging has been outlined.Описано перспективний метод технічного діагностування матеріалів із використанням сигналів магнетопружної акустичної емісії (МАЕ). Представлено результати числового розрахунку параметрів П-подібного електромагнета, призначеного для збудження з допомогою магнетного поля сигналів МАЕ у феромагнетних матеріалах. Представлено комп’ютеризовану вимірювальну систему, яка призначена для відбору, обробки та реєстрації сигналів МАЕ