СТРУКТУРНЫЕ ОСОБЕННОСТИ ПРИРОДНЫХ И ОБОГАЩЕННЫХ КАОЛИНОВ МЕСТОРОЖДЕНИЙ РЕСПУБЛИКИ БЕЛАРУСЬ

IR-spectroscopic results of study of primary kaolins of the Belarusian deposits «Sitnica» and «Dedovka» in a natural state and enriched by hydraulic sieve method are presented. The structural features of Belarusian kaolins as compared with known high-quality kaolin of Ukrainian deposits «Prosyanovskoe» are revealed, the values of crystallinity index are determined. Analysis of IR-spectra in the high-frequency region allowed us to establish the water connection forms in natural and enriched kaolins, the presence of OH-groups in the interlayer space, inside and on the surface of the octahedral layer and adsorbed water molecules, which can affect the rheology of kaolin suspensions. Silicate absorption band of kaolin, as well as intense peaks of deformation vibrations of quartz, typical for unenriched natural kaolin of Belarusian deposits, are in the lowfrequency region. Investigation using IR-spectroscopy made it possible to establish the structural features of natural kaolins related to the presence in the primary kaolin of the «Sitnitsa» and «Dedovka» deposits of the mineral of the kaolinite group of dikkite. The crystallinity index values (according to Hinckley) are established for natural and enriched kaolins «Sitnica» (0.94 and 1.11) and «Dedovka» (0.98 and 1.04) in comparison with kaolins of Prosyanovskoye deposit (1.31). Представлены результаты ИК-спектроскопического исследования первичных каолинов белорусских месторождений «Ситница» и «Дедовка» в природном состоянии и обогащенном гидравлическим ситовым способом. Выявлены структурные особенности каолинов Республики Беларусь по сравнению с известным высококачественным каолином украинского месторождения «Просяновское», определены значения индекса кристалличности. Анализ ИК-спектров в высокочастотной области позволил установить формы связи воды в природном и обогащенном каолинах, наличие ОН-групп в межслоевом пространстве, внутри и на поверхности октаэдрического слоя, а также адсорбированных молекул воды, что может оказать влияние на реологические свойства каолиновых суспензий. В низкочастотной области сосредоточены полосы поглощения силикатных структур каолинов, а также интенсивные пики деформацинных колебаний кварца, характерные для природных необогащенных каолинов белорусских месторождений. Исследование с помощью ИК-спектроскопии позволило установить структурные особенности природных каолинов, связанные с присутствием в первичных каолинах месторождений «Ситница» и «Дедовка» минерала каолинитовой группы диккита. Определены значения показателя индекса кристалличности (по Хинкли) для природных и обогащенных каолинов «Ситница» (0,94 и 1,11) и «Дедовка» (0,98 и 1,04) в сравнении с известным просяновским каолином (1,31).

The efficiency of using case-method for training staff of the higher qualification

В статье отмечено значение применения кейс-технологий для подготовки инженерных кадров высшей квалификации. Обозначено, что кейсовые чемпионаты являются эффективным инструментом для передачи будущим специалистам-инженерам практических знаний, опыта и новых компетенций. Приведены доказательства, что метод с использованием кейсов, имеет актуальность, эффективность и востребованность по сравнению с традиционными методами обучения, так как реализует главные образовательные аспекты: практическую направленность, интерактивный формат и конкретные навыки.The article notes the importance of using case technologies for the training of highly qualified engineering personnel. It is indicated that case championships are an effective tool for transferring practical knowledge, experience and new competencies to future engineers. Evidence is given that the method using cases is relevant, effective and in demand in comparison with traditional teaching methods, as it implements the main educational aspects: practical orientation, interactive format and Soft skills

nnovative Seasonal Migrations and Subsistence System of the Mobile Pastoralists of the Desert-Steppe Zone of Eurasia:role of social groups

The study of the economic system of the earliest nomads which inhabited the Eurasian desert-steppe belt in 5000-2000 is a relevant task of contemporary studies. The data on the organization of living space and the role of social groups of early prehistoric pastoralists in the exploitation of open steppe resources are scarce. The paper presents a new methodological approach to searching camps of the earliest pastoralists. The application of this approach enabled the archaeologists to discover numerous seasonal camps in the Sal-Manych Ridge located in the western part of the Eurasian steppes, including Eneolithic camps dated to 4200-3600 BC. The study of the occupation layers at the sites, evaluation of the productivity of pasture systems made it possible to categorize such sites as short-term seasonal camps occupied by pastoralists, evaluate the role of social groups in the organization of innovative seasonal migrations and reconstruct their subsistence system. The camps emerged as a result of developing pastoral economic strategy in the Lower Don region and the abutting areas reflecting the role of special social groups of pastoralists who managed to organize seasonal moves and address the issue of exploiting pastures located beyond the permanently occupied area

Hybrid nanoparticles based on sulfides, oxides, and carbides

The methods for synthesis of hybrid nanoparticles based on sulfides, oxides, and carbides of heavy and transition metals were considered. The problem of the influence of the method of synthesis of the hybrid nanoparticles on their atomic structure, morphology of the nanomaterials, and functional properties was analyzed. The areas of practical use of the hybrid nanoparticles were proposed. © 2013 Springer Science+Business Media New York

Origin of Axial and Radial Expansions in Carbon Nanotubes Revealed by Ultrafast Diffraction and Spectroscopy

The coupling between electronic and nuclear degrees of freedom in low-dimensional, nanoscale systems plays a fundamental role in shaping many of their properties. Here, we report the disentanglement of axial and radial expansions of carbon nanotubes, and the direct role of electronic and vibrational excitations in determining such expansions. With subpicosecond and subpicometer resolutions, structural dynamics were explored by monitoring changes of the electron diffraction following an ultrafast optical excitation, whereas the transient behavior of the charge distribution was probed by time-resolved, electron-energy-loss spectroscopy. Our experimental results, and supporting density functional theory calculations, indicate that a population of the excited carriers in the antibonding orbitals of the nanotube walls drives a transient axial deformation in ∼1 ps; this deformation relaxes on a much longer time scale, 17 ps, by nonradiative decay. The electron-driven expansion is distinct from the phonon-driven dynamics observed along the radial direction, using the characteristic Bragg reflections; it occurs in 5 ps. These findings reveal the nonequilibrium distortion of the unit cell at early times and the role of the electron(phonon)-induced stress in the lattice dynamics of one-dimensional nanostructures

Low-expanding ceramics based on ferrous cordierite

Целью данной работы является проведение исследований в области синтеза керамических материалов технического назначения на основе системы FeO-Al[2]O[3]-SiO[2], которая позволит выровнять недостатки традиционной кордиеритовой керамики