Phase formation behavior of alkali-activated calcined clays: effects of the reactive phase and NaOH concentration

Rakhimova Nailia R.,Morozov Vladimir P.,Eskin Aleksey A. 한국자원공학회 2021 Geosystem engineering Vol.24 No.5

The relevance of calcined clays as sources with a great potential for non-clinker alkali-activated materials has significantly increased in recent decades. This article reports on a study to investigate how NaOH with concentrations in the 5–14 M range affects the mechanical properties, amorphouscrystalline phase transformations, and reaction product composition of alkali-activated calcined kaolinite/montmorillonite cements with reactive phases of 60% and 33%, and with the SiO2/Al2O3 ratios of 1.54 and 1.74. The hardened pastes based on both calcined clays exhibited the highest compressive strength up to 9.1 MPa following their activation with 8 M NaOH. The higher amorphous fraction in the calcined clay provided gradual zeolitisation/crystallisation at Na2O/ SiO2 and Na2O/Al2O3 molar ratios in the 0.36–0.63 and 0.56–0.98 ranges, respectively, accompanied by the deterioration of the mechanical characteristics of the samples. The zeolite content in the alkali-activated calcined clay cements with an amorphous fraction of 33% peaked for NaOH at 11 M, and the corresponding molar ratios of Na2O/SiO2 and Na2O/Al2O3 were 0.85 and 1.46, respectively. The main reaction products in the studied systems determined by XRD, TG/DSC, and FTIR spectroscopy analyses were N-A-S-H and zeolite A. The properties and reaction products obtained favor the use of proposed alkali-activated cements for controlled low-strength materials.

Feedback Linearization of Nonlinear Singularly Perturbed Systems with State-dependent Coefficients

Aleksey A. Kabanov 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7

The article examines a feedback linearization (FL) problem for a nonlinear singular perturbed (SP) system in a state-dependent coefficients form (SDC-form). The combination of the composite control technique of singular perturbation theory and a canonical similarity transformation approach for systems in a SDC-form are explored in this research. As a result, two FL problems for a fast state variables subsystem and a slow state variables subsystem are solved separately. The transformation matrix and feedback linearizing control for the entire nonlinear SP system are designed as a composition of solutions of these two FL problems. The composite stabilizing controller, based on feedback linearization and a pole placement method, is proposed for a nonlinear SP system in a SDC-form. Practical implementation of the proposed feedback linearizing composite stabilizing control is shown through an example (an inverted pendulum, controlled by a direct current motor).

Multi-Platform Next-Generation Sequencing of the Domestic Turkey (<i>Meleagris gallopavo</i>): Genome Assembly and Analysis

Dalloul, Rami A.,Long, Julie A.,Zimin, Aleksey V.,Aslam, Luqman,Beal, Kathryn,Ann Blomberg, Le,Bouffard, Pascal,Burt, David W.,Crasta, Oswald,Crooijmans, Richard P. M. A.,Cooper, Kristal,Coulombe, Rog Public Library of Science 2010 PLoS biology Vol.8 No.9

<P>A synergistic combination of two next-generation sequencing platforms with a detailed comparative BAC physical contig map provided a cost-effective assembly of the genome sequence of the domestic turkey (<I>Meleagris gallopavo</I>). Heterozygosity of the sequenced source genome allowed discovery of more than 600,000 high quality single nucleotide variants. Despite this heterozygosity, the current genome assembly (∼1.1 Gb) includes 917 Mb of sequence assigned to specific turkey chromosomes. Annotation identified nearly 16,000 genes, with 15,093 recognized as protein coding and 611 as non-coding RNA genes. Comparative analysis of the turkey, chicken, and zebra finch genomes, and comparing avian to mammalian species, supports the characteristic stability of avian genomes and identifies genes unique to the avian lineage. Clear differences are seen in number and variety of genes of the avian immune system where expansions and novel genes are less frequent than examples of gene loss. The turkey genome sequence provides resources to further understand the evolution of vertebrate genomes and genetic variation underlying economically important quantitative traits in poultry. This integrated approach may be a model for providing both gene and chromosome level assemblies of other species with agricultural, ecological, and evolutionary interest.</P><P><B>Author Summary</B></P><P>In contrast to the compact sequence of viruses and bacteria, determining the complete genome sequence of complex vertebrate genomes can be a daunting task. With the advent of “next-generation” sequencing platforms, it is now possible to rapidly sequence and assemble a vertebrate genome, especially for species for which genomic resources—genetic maps and markers—are currently available. We used a combination of two next-generation sequencing platforms, Roche 454 and Illumina GAII, and unique assembly tools to sequence the genome of the agriculturally important turkey, <I>Meleagris gallopavo</I>. Our draft assembly comprises approximately 1.1 gigabases of which 917 megabytes are assigned to specific chromosomes. Comparisons of the turkey genome sequence with those of the chicken, <I>Gallus gallus</I>, and the zebra finch, <I>Taeniopygia guttata</I>, provide insights into the evolution of the avian lineage. This genome sequence will facilitate discovery of agriculturally important genetic variants.</P>

Comparative Analysis of Structural Changes in U-Mo Dispersed Fuel of Full-size Fuel Elements and Mini-rods Irradiated in the MIR Reactor

Aleksey L. Izhutov,Valeriy V. Iakovlev,Andrey E. Novoselov,Vladimir A. Starkov,Aleksey A. Sheldyakov,Valeriy Yu Shiishin,Vladimir M. Kosenkov,Aleksandr V. Vatulin,Irina V. Dobrikova,Vladimir B. Suprun 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.7

The paper summarizes the irradiation test and post-irradiation examination (PIE) data for the U-Mo low-enriched fuel thatwas irradiated in the MIR reactor under the RERTR Program. The PIE data were analyzed for both full-size fuel rods andmini-rods with atomized powder dispersed in Al matrix as well as with additions of 2%, 5% and 13% of silicon in the matrixand ZrN protective coating on the fuel particles. The full-size fuel rods were irradiated up to an average burnup of ~ 60%235U; the mini-rods were irradiated to an averageburnup of ~ 85%235U. The presented data show a significant increase of the void fraction in the U-Mo alloy as the U-235burnup rises from ~ 40% up to ~ 85%. The effect of irradiation test conditions and U-235 burnup were analyzed with regard tothe formation of an interaction layer between the matrix and fuel particles as well as generation of porosity in the U-Mo alloy. Shown here are changes in distribution of U fission products as the U-235 burnup increases from ~ 40% up to ~ 85%.

COMPARATIVE ANALYSIS OF STRUCTURAL CHANGES IN U-MO DISPERSED FUEL OF FULL-SIZE FUEL ELEMENTS AND MINI-RODS IRRADIATED IN THE MIR REACTOR

Izhutov, Aleksey.L.,Iakovlev, Valeriy.V.,Novoselov, Andrey.E.,Starkov, Vladimir.A.,Sheldyakov, Aleksey.A.,Shishin, Valeriy.Yu.,Kosenkov, Vladimir.M.,Vatulin, Aleksandr.V.,Dobrikova, Irina.V.,Suprun, V Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.7

The paper summarizes the irradiation test and post-irradiation examination (PIE) data for the U-Mo low-enriched fuel that was irradiated in the MIR reactor under the RERTR Program. The PIE data were analyzed for both full-size fuel rods and mini-rods with atomized powder dispersed in Al matrix as well as with additions of 2%, 5% and 13% of silicon in the matrix and ZrN protective coating on the fuel particles. The full-size fuel rods were irradiated up to an average burnup of ${\sim}60%^{235}U$; the mini-rods were irradiated to an average burnup of ${\sim}85%^{235}U$. The presented data show a significant increase of the void fraction in the U-Mo alloy as the U-235 burnup rises from ~ 40% up to ~ 85%. The effect of irradiation test conditions and U-235 burnup were analyzed with regard to the formation of an interaction layer between the matrix and fuel particles as well as generation of porosity in the U-Mo alloy. Shown here are changes in distribution of U fission products as the U-235 burnup increases from ~ 40% up to ~ 85%.

Structures, Energetics, and IR Spectra of Monohydrated Inorganic Acids: Ab initio and DFT Study

Kołaski, Maciej,Zakharenko, Aleksey A.,Karthikeyan, S.,Kim, Kwang S. American Chemical Society 2011 Journal of chemical theory and computation Vol.7 No.10

<P>We carried out extensive calculations of diverse inorganic acids interacting with a single water molecule, through a detailed analysis of many possible conformations. The optimized structures were obtained by using density functional theory (DFT) and the second order Møller–Plesset perturbation theory (MP2). For the most stable conformers, we calculated the interaction energies at the complete basis set (CBS) limit using coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. The −OH stretching harmonic and anharmonic frequencies are provided as fingerprints of characteristic conformers. The zero-point energy (ZPE) uncorrected/corrected (Δ<I>E</I><SUB>e</SUB>/Δ<I>E</I><SUB>0</SUB>) interaction energies and the enthalpies/free energies (Δ<I>H</I><SUB>r</SUB>/Δ<I>G</I><SUB>r</SUB> at room temperature and 1 bar) are reported. Various comparisons are made between many diverse inorganic acids (H<SUB><I>m</I></SUB>XO<SUB><I>n</I></SUB> where X = B/N/P/Cl/Br/I, <I>m</I> = 1–3, and <I>n</I> = 0–4) as well as other simple inorganic acids. In many cases, we find that the dispersion-driven van der Waals interactions between X in inorganic acid molecules and O in water molecules as well as the X<SUP>+</SUP>···O<SUP>–</SUP> electrostatic interactions are important.</P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ct100428z'>ACS Electronic Supporting Info</A></P>

Effect of nano-carbon dispersions on signal in silicon-based sensor structure with photoelectrical transducer principle

Anton I. Manilov,Aleksey V. Kozinetz,Sergiy V. Litvinenko,Valeriy A. Skryshevsky,Mohammed Al Araimi,Alex Rozhin 한국물리학회 2019 Current Applied Physics Vol.19 No.3

We identified different nano-carbon species such as graphene nanoplatelets, graphite flakes and carbon nanotubes dispersed in N-methyl-2-pyrrolidone using a novel sensor structure based on a “deep” silicon barrier working as a photoelectrical transducer. Each nano-carbon particle has specific signature in both 2D photocurrent distribution and photocurrent dependencies on bias changing surface band-bending. Additionally, all nano-carbon particles have characteristic features in the time-dependent evolution of photocurrent. The obtained results can be explained by the influence of nano-carbon molecules' local electric field on the recombination parameters of defect centers on the silicon surface.

Influence of calcined medium grade clay on the properties of Portland cement pastes

Rakhimova Nailia R.,Morozov Vladimir P.,Eskin Aleksey A. 한국자원공학회 2022 Geosystem engineering Vol.25 No.6

In the recent decades, the composition of Portland cements has undergone significant changes related to an increase in the range and content of supplementary cementitious materials following development of composite and multicomposite cements. The development of these binders that meet the requirements of sustainability requires the expansion and adaptation of the mineral resource base of cement industry to the production of low-emission binders with a gradual decrease of resource and energy intensities. Efforts to find the widespread sources of pozzolans providing high reactivity and physical–chemical stability have led to intensive studies on thermally treated clays of various chemical–mineralogical composition and their industrial adoption. Due to scarcity and high cost of kaolin clays, great attention is given to medium- and low-grade clays. This article reports on a study to evaluate the effect of calcined clay with 52% of clay minerals on the properties of fresh and hardened pastes, in particular on the resistance to sodium sulfate and nitric acid attacks. The reaction products assemblage of the blended Portland cement pastes was investigated by XRD and thermal analyses. The hardened Portland cement pastes incorporated with thermally treated clay demonstrated better durability performance compared to reference ones.

Calcined low-grade multimineral clays as supplementary cementitious materials: a feasibility study

Rakhimova Nailia R.,Rakhimov Ravil Z.,Bikmukhametov Artur R.,Morozov Vladimir P.,Eskin Aleksey A.,Gubaidullina Alfiya M. 한국자원공학회 2020 Geosystem engineering Vol.23 No.3

The relevance of calcined clays as sources with great potential for low-clinker blended Portland cements has significantly increased in recent decades. This article reports on a study to evaluate the potential of the two low-grade clays containing 9.37% of montmorillonite/chlorite and 12.26% of montmorillonite/kaolinite/chlorite accompanied with 29.73% and 32.79% of calcite, respectively, as supplementary cementitious materials. The clays after thermal treatment at 800°C demonstrated poor pozzolanic activity, slight increase in the C-(S)-H and decline in the CH contents, and decrease in the mechanical properties of the blended Portland cement pastes. The results showed that the investigated clays fall below the range of the clays suitable for pozzolan production.

Routing in the multi-coordinate associative switching systems

Aleksey V.Son,Svetlana A. Sadchikova,Vladimir M.Son,Hyung-Moo Park,Jin-Koo Rhee 대한전자공학회 2003 ITC-CSCC :International Technical Conference on Ci Vol.2003 No.7