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Rogazinsksya O.V.,Voronezh State University | Sidorkin A.S.,Voronezh State University | Milovidova S.D.,Voronezh State University | Naberezhnov A.A.,RAS Ioffe Physical - Technical Institute | And 3 more authors.
Bulletin of the Russian Academy of Sciences: Physics | Year: 2011

The dielectric nonlinearity and pyroeffect in matrix composite based on porous glass with inclu-sions of sodium nitrite are investigated. It is found that the composite polarization turns to zero at a temper-ature below that of the phase transition in the bulk NaNO2. The obtained dependence of the pyrocoefficient on temperature also corroborates the existence of the phase transition in sodium nitrite nanoparticles included in the porous matrix. © Allerton Press, Inc., 2011. Source

Morkovina S.S.,Voronezh State Academy of Forestry and Technologies
Life Science Journal | Year: 2014

In this article we study the theoretical-methodological approach to provision of development of small and medium-sized entrepreneurship in the system of forestry management. The instruments of stating the forms of state and entrepreneurship cooperation and organization of entrepreneurial activity in forestry management of sparsely wooded region were suggested. The principles of differentiation of woodlots of sparsely wooded regions in conditions of provision of balance of interests of wood resources owner and forest users-enterprises owners were also provided. We have also suggested the algorithm, which allows defining the predisposition of the region (forestry district, group of forestry districts) to developing certain forms of entrepreneurship. Source

Novikova L.,Voronezh State Academy of Forestry and Technologies | Roessner F.,Carl von Ossietzky University | Belchinskaya L.,Voronezh State Academy of Forestry and Technologies | AlSawalha M.,Jubail Industrial College | Krupskaya V.,RAS Institute of Geology and Mineralogy
Applied Clay Science | Year: 2014

Surface acid-base properties of natural clays and non-clay minerals from Jordanian (J) and Russian (R) deposits as well as H-ZSM-5 were studied applying catalytic reaction of 2-methylbut-3-yn-2-ol (MBOH) conversion. Products of both acidic and basic pathways of the reaction were formed involving surface acid/basic sites of clay minerals. Specific conversions of MBOH decreased in the following order: kaolinite-R>hydromica-R>bentonite-J>red-kaolinite-J=palygorskite-R=H-ZSM-5>zeolite-J>white-kaolinite-J>diatomite-J, which fairly correlated with TPD-NH3 acidity assessment for a majority of samples. However, a contribution of basic sites to the reaction should be taken into account, especially for hydromica-R and kaolinite-R.The strength of acid sites of natural aluminosilicates was compared based on surface acidity and reaction product yields. After 116. min of MBOH conversion, the strength of acid sites changed in the following order: kaolinite-R. >. palygorskite-R. >. bentonite-J. >. red- kaolinite-J. >. white-kaolinite-J. >. zeolite-J. >. diatomite-J. >. H-ZSM-5. At an early (17. min) stage of the reaction, the strength of active sites for natural zeolite-J and H-ZSM-5 were comparable, while the latter underwent significant deactivation due to its microporous structure.The rise of activation temperature from 500. °C to 700. °C for montmorillonite containing sample increased the conversion of MBOH due to the formation of stronger or additional number of basic sites as a result of mineral dehydroxylation. Natural clay samples with a higher content of montmorillonite (30-80%) altered the acid-base properties of the surface and observed higher ability to convert MBOH over acid and basic pathways. © 2014 Elsevier B.V. Source

Novikova L.,Voronezh State Academy of Forestry and Technologies | Belchinskaya L.,Voronezh State Academy of Forestry and Technologies | Roessner F.,Carl von Ossietzky University | Alsawalha M.,Jubail Industrial College
Acta Geodynamica et Geomaterialia | Year: 2013

Catalytic test reaction of methylbutynol (MBOH) conversion was applied to investigation of natural clays and non-clay minerals from Jordanian (bentonite, kaolinite, diatomite, zeolite) and Russian (palygorskite, kaolinite, hydromica) deposits as well as H-ZSM-5. Palygorskite and kaolinite containing samples have shown the highest catalytic activity. Conversion over Jordanian clay minerals decreased in the order: zeolite > bentonite > red kaolinite > white kaolinite > diatomite that agreed to change of acidity, surface area of samples. Sufficient deactivation was observed for H-ZSM-5, kaolinite and hydromica due to adsorption of secondary product in micropores of raw minerals. Products of both acidic and basic pathways of test reaction were formed indicating the presence of acid and basic sites on clays surface, apart from acidic catalyst H-ZSM-5. The yield ratio of acidic to basic products was above the unity for zeolite, bentonite, red kaolinite, and palygorskite; equal to unity for diatomite and hydromica, and less then unity for white kaolinite. It was observed for kaolinite containing sample that high activation temperature increased conversion of MBOH owing to formation of additional basic sites as a result of mineral dehydroxylation. Rise of montmorillonite content from 30 to 80 % provided 91-97 % of MBOH conversion. Source

Alsawalha M.,Jubail Industrial College | Roessner F.,Carl von Ossietzky University | Novikova L.,Voronezh State Academy of Forestry and Technologies | Bel'chinskaya L.,Voronezh State Academy of Forestry and Technologies
World Academy of Science, Engineering and Technology | Year: 2011

The acidity of different raw Jordanian clays containing zeolite, bentonite, red and white kaolinite and diatomite was characterized by means of temperature programmed desorption (TPD) of ammonia, conversion of 2-methyl-3-butyn-2-ol (MBOH), FTIR and BET-measurements. FTIR spectra proved presence of silanol and bridged hydroxyls on the clay surface. The number of acidic sites was calculated from experimental TPD-profiles. We observed the decrease of surface acidity correlates with the decrease of Si/Al ratio except for diatomite. On the TPD-plot for zeolite two maxima were registered due to different strength of surface acidic sites. Values of MBOH conversion, product yields and selectivity were calculated for the catalysis on Jordanian clays. We obtained that all clay samples are able to convert MBOH into a major product which is 3-methyl-3-buten-1-yne (MBYNE) catalyzed by acid surface sites with the selectivity close to 70%. There was found a correlation between MBOH conversion and acidity of clays determined by TPD-NH 3, i.e. the higher the acidity the higher the conversion of MBOH. However, diatomite provided the lowest conversion of MBOH as result of poor polarization of silanol groups. Comparison of surface areas and conversions revealed the highest density of active sites for red kaolinite and the lowest for zeolite and diatomite. Source

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