Development of methods for preparing fly ash for separation by activation

Purpose. Isolation of the aluminosilicate fraction from fly ash, study of physical and mechanical properties of binders obtained from TPP wastes. Methods. Ash, carbon concentrate (underburn), ash concentrate and products of their treatment with reagents were tested by optical methods. The morphology of the particles of the subjects of inquiry was studied with the scanning electron microscope REM-100. The composition of the ash phases was investigated using the X-ray diffractometer DRON-2. Findings. The technology of sorbents based on coal combustion products through a variety of methods was researched. It is shown that these sorbents are distinctive because their structure has non-localized pi-electrons of the graphite-like networks of crystallites of carbon. This circumstance determines not only the uniqueness of electro-physical properties of coal but also adsorption, redox, chemisorption processes on the border of coalslurry. The listed circumstances allow you to use the original methods of chemical and mechanochemical modification of the surface chemical and coal, due to introducing desired donor and acceptor atoms in carbon frame, which increases the absorption capacity and selectivity carbon sorbents. Practical implications. The article presents the results of receipt of binders based on TPP ash. It has been shown that a component of the fly ash is aluminosilicate spheres that can be used in the production of lightweight concrete. It is proved that the result of mechanochemical activation mixture consisting of alumino-silicates, resulting lightweight concrete has high strength 7-8 MPa, which allows, while maintaining the technical characteristics save from 20 to 30 % of binder. Concrete obtained based on aluminosilicate spheres separated from fly ash may be used to prepare the outer wall construction, small building blocks, as well as monolithic housing. In comparison with known compositions keramsit compositions comprising TPP waste

Thermodynamic forecasting of formation nonmetallic oxidic inclusions in seam metal at arc welding under highsiliceous gumboils content

В процесі електродугового зварювання під флюсом утворюються неметалеві включення різної морфології, із змінною об'ємною долею їх в металі шва. Розроблена фізична модель утворення оксидних неметалевих включень в металі шва. Запропонована термодинамічна модель утворення оксидних неметалевих включень в металі шва при електродуговому зварюванні під флюсом на основі створеної фізичної моделі. Проведені металографічні дослідження з вивчення вмісту неметалевих включень в металі шва і їх морфології, показано адекватність запропонованої термодинамічної моделі.At arc welding under gumboil are formed nonmetallic inclusions of different morphology, with their variable volume fraction in seam metal. The physical model of formation of nonmetallic oxidic inclusions in seam metal is developed. The thermodynamic model of formation of oxidic nonmetallic inclusions in seam metal at arc welding under gumboil on the basis of the created physical model is offered. The conducted metalgraphic researches on studying of content of nonmetallic inclusions in metal of a seam and their morphology, have shown adequacy to the offered thermodynamic model Purpose. Creation of settlement thermodynamic model of formation of oxidic nonmetallic inclusions in seam metal at arc welding under gumboil of general purpose. Determination of adequacy to the offered model when using gumboils of various slag systems, and at a variable ratio of components as a part of gumboil. Design/methodology/approach formulate the basic principles of application of equilibrium chemical thermodynamics for modeling of process of formation of oxidic nonmetallic inclusions in seam metal; create thermodynamic model of determination of content of oxidic nonmetallic inclusions in seam metal at arc welding under gumboil; conduct pilot studies for an assessment of adequacy to the developed model of formation of oxidic nonmetallic inclusions. Findings. It is offeredthe thermodynamic model of formation of oxidic nonmetallic inclusions in seam metal at arc welding underПри электродуговой сварке под флюсом образуются неметаллические включения разной морфологии, с переменной объемной долей их в металле шва. Разработана физическая модель образования неметаллических оксидных включений в металле шва. Предложена термодинамическая модель образования оксидных неметаллических включений в металле шва при электродуговой сварке под флюсом на основе созданной физической модели. Проведенные металлографические исследования по изучению содержания неметаллических включений в металле шва и их морфологии, показали адекватность предложенной термодинамической модели

Dielectric characteristics of GaSe nanocrystals intercalated with hydrogen

The results of investigations of dielectric characteristics of GaSe nanocrystals and their hydrogen intercalates are presented. By using the impedance spectroscopy method, it is established that the dielectric spectra of GaSe and HxGaSe (х = 0.07 and 0.14) nanocrystals correspond to the exponent law of dielectric response. It is found that there is an increase of the dielectric constant ε∞ for the intercalated samples in comparison with that of the initial sample. We have obtained the frequency dependences of the real and imaginary parts of the conductivity, whose dispersion is due to the presence of two-dimensional defects. Equivalent electrical circuits which determine electrical characteristics of the crystals under study are proposed

Зміна оптичних властивостей моноселенідів індію і галію при термічному впровадженні NaNO2

The effect of the thermal introduction of NaNO2 on the optical properties of indium and gallium monoselenides was investigated. The transmission spectra of InSe and GaSe and their NaNO2-intercalates were identified by means of the installation spectrometric collected on the basis of monochromator MDR-23. It was found that the time dependence of the concentration of NaNO2-intercalates has the non-monotonic character with areas of different intercalation speeds.Досліджено спектри пропускання в області екситонного поглинання для монокристалів InSe і GaSe, експонованих в розплаві солі NaNO2. Встановлені немонотонні концентраційні залежності енергетичного положення екситонного максимуму Еекс. Встановлено, що немонотонний зсув, який спостерігається при Т = 77 К для максимуму Еекс при збільшенні часу витримки, обумовлений виникненням міжшарових деформаційних напруг та зміни величини ε0 діелектричної постійної кристалу внаслідок впровадження інтеркалянта в міжшаровий простір

Increasing the durability of working bodies of mining and metallurgical complex equipment by electroslag surfacing in a current-carrying crystallizer

Представлено результати виконання електрошлакових наплавок електродом великого перерізу та дробом у струмопідвідних кристалізаторах різного перерізуThe results of electroslag surfacing with a large-section electrode and shot incurrent-carrying crystallisers of different cross-sections are presente

Estimation of damage risks for the weld assembly between the header and the steam generator nozzle in a WWER NPP

Tasks involved in determination of the NPP equipment failure risks in the process of long-term operation are of extreme importance nowadays, specifically as the NPP units in the Russian Federation are nearing the end of their design lifetimes (25–30 years) and the life of newly built NPPs is increased to 60 years. The end of the effective NPP lifetimes and the increase in the operating life for newly built NPPs dictate the need for new approaches to be developed to ensure safe and reliable operation of critical thermomechanical components and pipelines. One of such components is the weld assembly between the hot header and the steam generator shell (WJ 111), in which formation and high-rate development of in-service defects is possible; the defects being systemic and affecting the operating safety of the entire power unit. Statistics is presented on failures in the weld assembly between the SG hot/cold headers and the DN-1200 piping for WWER reactors. Classification is proposed for the occurrence of limiting failure states for the SG weld assembly. The risk has been calculated for a power unit in the event one of the limiting states occurs. The losses resulting from damage to the SG header—nozzle weld assembly in the WJ 111 area is substantial. The probability of intolerable defects in the WJ 111 area remains high, so measures are required to control their formation time and development process

Electrical and photoelectrical properties of n-InSe/p-CuInSe₂ optical contact

Photosensitive heterojunctions were created by the method of optical contact of layered semiconductor InSe to CuInSe₂ plates. Due to high quality of contacting surfaces, a strong and enough perfect electrical junction is formed. To understand processes occurring in such heterojunctions, the measurements of current-voltage characteristics in forward and reverse directions, photoelectric modification of the direct branch of the current-voltage characteristic, capacitance-voltage characteristic, spectrum of the relative quantum efficiency have been carried out at the room temperature. The structures had a well-pronounced photovoltaic effect – the open-circuit voltage was 0.5 V and the short-circuit current density – 0.7 mА/cm². The conclusion about possibility of application of the obtained heterojunctions as photodetectors is made

Хімія. Методичні рекомендації та завдання до самостійної роботи з дисципліни для студентів усіх спеціальностей (частина 1)

The methodical instructions contain individual tasks in the course of chemistry, which are compiled on the topics of the theoretical course.Методичні рекомендації містять індивідуальні завдання відповідно до тем теоретичного курсу хімії

Основні поняття й закони хімії. Методичні рекомендації та завдання.

The theoretical themes of "Basic concepts and laws of chemistry", are examples of solving common tasks, in order to consolidate the material there are presented self-study tasks for solving.Розглянуто теоретичні положення теми «Основні поняття й закони хімії», наведено приклади розв’язку типових задач з метою закріплення матеріалу, подано задачі для самостійного розв’язування

Хімія. Методичні рекомендації та завдання [Електронний ресурс]: до самост. роботи з дисц. для студ. усіх спец-тей. Ч. 1

The methodical instructions contain individual tasks in the course of chemistry, which are compiled on the topics of the theoretical course.Методичні рекомендації містять індивідуальні завдання відповідно до тем теоретичного курсу хімії