Microstructural Changes in Ni-Al-Cr-Based Heat-Resistant Alloy with Re Addition

This paper presents scanning and transmission electron microscope investigations of the structure, phase composition, and morphology of a heat-resistant alloy modified by thermal treatment and additionally alloyed by rhenium. The rhenium alloy was obtained by using the directional crystallization technique. The structural investigations were carried out for two states of the alloy, i.e., (1) original (after the directional crystallization); (2) after the directional crystallization with 1150 °C annealing for 1 h and 1100 °C annealing for 480 h. It is shown that fcc-based γ- and γ′-phases are primary in all states of the alloy. The γ′-phase has an L12 structure, while γ-phase is a disordered phase. It was found that after directed crystallization, the volume fraction of the γ′ phase is ~85%, the fraction of the γ-phase is less than 10%. Annealing leads to an increase in the γ′- phase up to 90%, the proportion of the γ-phase practically does not change. Rhenium is a phase-formation element. The investigations show that high-temperature annealing modifies the structural and phase conditions of the heat-resistant alloy

Fine structure and phase composition of Fe–14Mn–1.2C steel: influence of a modified mixture based on refractory metals

The effect of TiO2, ZrO2 and Na3AlF6 ultrafine powders on the fine structure and the phase composition of Fe–14Mn–1.2C steel was investigated. The introduction of the ultrafine powders into the melt influenced the grain size, the quantity, and the character of distribution of nonmetallic inclusions in the railroad frogs. The microstructure of castings was improved significantly because of the refinement of the grain structure and an increase of the grain-boundary area. After the modifying mixture was introduced into the melt, either the microtwins of one or two intersecting systems or the precipitations of ε-martensite of different types, or simultaneously the microtwins and wafers of ε-martensite, were present in each grain

Fine structure and phase composition of Fe–14Mn–1.2C steel: influence of a modified mixture based on refractory metals

The effect of TiO2, ZrO2 and Na3AlF6 ultrafine powders on the fine structure and the phase composition of Fe–14Mn–1.2C steel was investigated. The introduction of the ultrafine powders into the melt influenced the grain size, the quantity, and the character of distribution of nonmetallic inclusions in the railroad frogs. The microstructure of castings was improved significantly because of the refinement of the grain structure and an increase of the grain-boundary area. After the modifying mixture was introduced into the melt, either the microtwins of one or two intersecting systems or the precipitations of ε-martensite of different types, or simultaneously the microtwins and wafers of ε-martensite, were present in each grain

THE POSSIBILITIES OF EXTRACTION APPROACH FOR RECOVERING OF METALS FROM OIL PRODUCTS

The extraction approach for recovering of trace elements from oil/oil products are proposed in this work. It has been shown that most of elements are extracted from oil/oil products to mineral acids solutions. Extraction degree of most valuable metals during the process varies from 75 to 90%. The proposed method could be used as a new cheap, precise and time saving analytical method (as compared to standard methods) of elemental analysis of the oil and the approach for development of effective technology for metal recovery from organic matrices

MULTIPLE PREGNANCY, ANTENATAL CARE PROBLEMS AND THEIR SOLUTIONS RESULTS

Aim of the work. The aim of our study is to summarize the course of pregnancy and delivery in multiple pregnancies in modern conditions.Materials and methods. The analysis of the pregnancy course, labor and perinatal outcomes was carried out in 182 women with diochorionic and 86 patients with monochorionic twins and 40 women with a singleton pregnancy. Multiple pregnancies were proved to be a monochorionic (MH) and diochorionic (DH) that is a high risk factor for perinatal complications. The research included clinical and laboratory examination metods, study of hormonal function of fetoplacental complex (FPC), transvaginal ultrasound examination. Statistical processing of data was carried out using the package of applied programs Microsoft Office Excel 2010 and StatSoft Statistica 6.1.Results and discussion. In the analysis of pregnancy the abortion threat was detected in 51 (59.3%) women with monochorionic and 34 (62%) women with diochorionic twins. Preeclampsia during pregnancy complicated in 26 (30.2%) and 43 (23.6%) patients, with monochorionic and diochorionic placentation type, respectively. A frequent complication of both the MH and DH twins was anemia, which was found in more than half of the surveyed (56.9 and 51%, respectively). Delivery in the case of multiple pregnancies is also much more complicated and is terminated surgically three times more often than in singleton births. The most frequent indications for operative delivery were first breech fetus, fetal distress during pregnancy and childbirth, FGR, severe preeclampsia, premature detachment of normally situated placenta, anomalies of labor activity. These perinatal losses were equally observed both after cesarean section and after spontaneous labor and amounted to 4% at monochorionic and 1.7% at diochorionic twins.The frequency dependence of identified lesions at pregnancy with twins was established by chorionic. Careful observation of the patients with multiple pregnancies in the antenatal period, the prevention of the most frequent complications, ultrasound monitoring of early pregnancy allows a differentiated approach to the management of pregnancy and childbirth, helping to reduce perinatal morbidity and mortality.Conclusions. Multiple pregnancies occur with a large number of complications compared with singletons. Thus, the increase of frequency of multiple pregnancy influences the obstetric and perinatal indicators, pushing this issue in a number of the most pressing issues of modern obstetrics and perinatology