Tashkent Institute of Chemical Technology

Tashkent, Uzbekistan

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Hojamberdiev M.,Alfred University | Hojamberdiev M.,Xi'an University of Architecture and Technology | Hojamberdiev M.,TU Darmstadt | Eminov A.,Tashkent Institute of Chemical Technology | Xu Y.,Xi'an University of Architecture and Technology
Ceramics International | Year: 2011

Granite waste is by-product from a decorative rock industry. The present study aims to investigate the effect of muscovite granite waste on the physico-mechanical properties of ceramic tiles to demonstrate its suitability for industrial production. A series of flooring- and facing ceramic tiles were prepared by adding 20, 25, and 30 wt% muscovite granite waste into the batch compositions. The sintering behavior and degrees of densification of two kinds of ceramic tiles were evaluated by determining their physico-mechanical properties and characterizing them by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. As expected, the facing ceramic tile (FacCT1) sample, containing wollastonite, hematite, anorthite, quartz, and cristobalite, with 20 wt% muscovite granite waste showed lower physico-mechanical properties than those of the flooring ceramic tile (FloCT3) sample, containing mullite, calcium aluminosilicate, quartz, and cristobalite, with 30 wt% muscovite granite waste. The reason is that lower firing temperatures cannot accelerate a complete fusion of the granite waste which behaves like an inert non-plastic material similar to quartz. These results illustrate the prospects of utilizing muscovite granite waste in ceramic tile production. © 2010 Elsevier Ltd and Techna Group S.r.l.

Hojamberdiev M.,Shaanxi Normal University | Hojamberdiev M.,Tokyo Institute of Technology | Zhu G.,Shaanxi Normal University | Eminov A.,Tashkent Institute of Chemical Technology | Okada K.,Tokyo Institute of Technology
Journal of Cluster Science | Year: 2013

Hollow α-FeOOH urchin-like spheres were synthesized by a simple hydrothermal method at 160 °C for 12 h and their thermal conversion to hollow α-Fe2O3 urchin-like spheres was performed at 300 °C for 2 h in air. The results from X-ray diffraction and electron microscopy analyses reveal that hollow α-FeOOH urchin-like spheres were completely transformed to hollow α-Fe2O3 urchin-like spheres without a significant morphological change. Also, the effect of hydrothermal treatment temperature (170-200 °C for 12 h) on the phase structure and morphology of the final product was investigated. Pure α-FeOOH, the mixture of α-FeOOH and α-Fe2O3, and pure α-Fe2O3 with different morphologies were obtained at <180, 180-190 and 200 °C, respectively. The obtained materials can be used in the photodegradation of organic pollutants under visible light irradiation. © 2012 Springer Science+Business Media New York.

Krivorotov V.F.,Academy of Sciences of Uzbekistan | Khabibullaev P.K.,Academy of Sciences of Uzbekistan | Fridman A.A.,Academy of Sciences of Uzbekistan | Sharipov K.T.,Tashkent Institute of Chemical Technology
Inorganic Materials | Year: 2010

The energetics of lattice disordering in crystals with the LaF 3 structure has been studied by Raman spectroscopy. Analysis of the width of Raman lines indicates that, for T < T c (in the dielectric phase of LaF 3), the activation energy for anion disordering is E d ≃ 0.20 eV. This value agrees well with the 0.22 eV obtained as the difference between the energies of a fluoride ion in lattice and interstitial sites in a finite crystalline LaF 3 cluster. © 2010 Pleiades Publishing, Ltd.

Krivorotov V.F.,Academy of Sciences of Uzbekistan | Khabibullaev P.K.,Academy of Sciences of Uzbekistan | Sharipov K.T.,Tashkent Institute of Chemical Technology
Inorganic Materials | Year: 2010

The mechanism of lattice "melting" in tysonite-structure superionic trifluorides is analyzed in relation to the structure of LaF 3 crystals. The ion displacements within the unit cell are shown to correlate with the dynamics of the Raman scattering parameters of the crystals. The frequency and intensity of the lines at 370, 392 (LaF 3), 376, and 404 cm -1 (PrF 3) show anomalous behavior in three temperature ranges: 160- 180, 240-280, and 420-460 K. The anomalies in the two higher temperature ranges are due to lattice disor- dering in the superionic transition region. The scattering in the range 160-180 K is tentatively attributed to fluoride ion displacements in split sites with a few potential wells. It is shown based on a split-site model that the thermally activated formation of interstices comparable in size to the mobile fluoride ion is an inherent feature of the LnF 3 structure. © Pleiades Publishing, Ltd., 2010.

Krivorotov V.F.,Academy of Sciences of Uzbekistan | Khabibullaev P.K.,Academy of Sciences of Uzbekistan | Fridman A.A.,Academy of Sciences of Uzbekistan | Sharipov K.T.,Tashkent Institute of Chemical Technology
Inorganic Materials | Year: 2010

We examine the behavior of the entropy (S d), enthalpy (H), and concentration of disordered fluoride ions (n) in LaF 3 in a broad temperature range around its critical temperature using a model for structural lattice disordering. We analyze the relationship between the free energy of a crystal and LaF 3 lattice disordering parameters: entropy, S d; anion sublattice disordering energy, E a; and the concentration of vacancy-interstitial defect complexes, n. H(T), n(T), and S d(T) data are obtained for the phase transition region. © 2010 Pleiades Publishing, Ltd.

Uchendu E.E.,Oregon State University | Uchendu E.E.,University of Guelph | Muminova M.,Tashkent Institute of Chemical Technology | Gupta S.,Tissue Culture and Cryopreservation Unit | Reed B.M.,National Clonal Germplasm Repository
In Vitro Cellular and Developmental Biology - Plant | Year: 2010

Regrowth of plants after cryopreservation varies, and resulting regrowth ranges from poor to excellent. Oxidative stress is a potential cause of damage in plant tissues. Antioxidants and anti-stress compounds may improve regrowth by preventing or repairing the damage. Lipoic acid (LA), glutathione (GSH), glycine betaine (GB), and polyvinylpyrrolidone (PVP) were tested during cryopreservation of shoot tips using the plant vitrification solution 2 (PVS2) protocol. Two in vitro-grown blackberry cultivars were cold acclimated and then cryopreserved in liquid nitrogen (LN). The antioxidant and anti-stress compounds were added at four critical steps of the protocol: pretreatment, loading, rinsing, and regrowth. Three out of the four compounds significantly improved regrowth of cryopreserved shoot tips. Regrowth ranged from 40% to 50% for controls to >80% for treated shoot tips. LA (4-8 mM) produced high regrowth at pretreatment, loading, and rinsing for 'Chehalem' and at all steps for 'Hull Thornless'. Recovery improved at all steps with GSH (0.16 mM) and GB (10 mM). PVP had a neutral or negative impact on regrowth. Overall addition of LA, GSH, and GB improved regrowth by ̃25% over the shoot tips cryopreserved using the regular PVS2 protocol (control). This study shows that adding non-vitamin antioxidants and anti-stress compounds during the PVS2-vitrification protocol improves regrowth of shoot cultures following cryopreservation. We recommend inclusion of antioxidants as part of standard cryopreservation protocols. © 2010 The Society for In Vitro Biology.

Bassil N.V.,U.S. Department of Agriculture | Muminova M.,Tashkent Institute of Chemical Technology | Njuguna W.,Oregon State University
Acta Horticulturae | Year: 2010

The blackberry industry needs a reliable method to ensure trueness-to-type of blackberry products. Microsatellite markers or simple sequence repeats (SSRs) are ideal for cultivar fingerprinting, paternity testing and identity certification. Fingerprinting is valuable for variety identification, quality control and as a legal method to protect against infringement by competitors. The objectives of this study were to develop a DNA extraction protocol and SSR-based identification for individually quick-frozen (IQF) 'Marion' and 'Kotata' whole berries and concentrate and to generate genetic fingerprints for 16 important western blackberry cultivars. IQF berries and frozen concentrate of 'Marion' and 'Kotata' were generously provided by reliable commercial sources. The FAST ID Kit worked better than two other DNA extraction methods for isolating DNA from IQF berries and from frozen and thawed concentrate. Out of twenty-nine SSRs tested, ten polymorphic SSRs differentiated between 'Marion' and 'Kotata' leaves and were chosen for subsequent analyses. SSR-based fingerprinting of individual IQF berries (using the receptacle for DNA extraction) revealed a mixture of 'Kotata' and 'Marion' berries in the commercial 'Marion' bag while fingerprinting of frozen 'Marion' concentrate identified 'Kotata' in the small frozen puree sample evaluated and possible contamination from seed DNA. The ten SSRs differentiated between each of the 16 western cultivars included in this study. In fact, one SSR marker, Rubus 275a was sufficient to distinguish these 16 cultivars. In summary, blackberry can be reliably identified with SSR markers, using leaves and frozen berries as sources of DNA. Fingerprinting from concentrate does not appear reliable for identity certification due to possible contamination from seed DNA.

Boboev A.,University of Chemical Technology and Metallurgy of Sofia | Hasanov A.,Tashkent Institute of Chemical Technology | Yotova L.,University of Chemical Technology and Metallurgy of Sofia | Hasanov H.,Tashkent Institute of Chemical Technology
Bulgarian Journal of Agricultural Science | Year: 2012

Enzymatic hydrolysis of various wheat proteins and cottonseed with acid (Prolive PAC 30L "EnzymeBioProduct" Ltd, Russia) and neutral proteases (Neutrase, "Novozymes", Denmark) was studied. The antioxidant properties of the produced peptides depended on the properties of the proteins and enzymes used. It was shown that when using acid protease peptides, derived from wheat albumin possess 10-12 times higher reducing power than peptides derived with neutral protease. When using cottonseed albumin, a different relationship was established. Reducing power of peptides, produced with neutral protease was 2-3 times higher than peptides processed using acid proteases. When hydrolyzing cottonseed globulin, the reducing power of the resulting peptides is higher, when acid protease is used. In a model system, the highest inhibition rate of oxidation of (+)-catechin is observed when peptides derived from cottonseed and wheat proteins with neutral proteases were used. In all cases, peptides derived with acid protease reduce the rate of oxidation of (+)-catechin to a smaller degree. Apart from having antioxidant activity, the peptides can also affect the activity of antioxidant enzymes. Activating effect is observed at low degrees of hydrolysis of albumin and it depends on the type of the enzyme and the substrate protein.

Azimov F.,University of Chemical Technology and Metallurgy of Sofia | Azimov F.,Tashkent Institute of Chemical Technology | Markova I.,University of Chemical Technology and Metallurgy of Sofia | Stefanova V.,University of Chemical Technology and Metallurgy of Sofia | Sharipov K.,Tashkent Institute of Chemical Technology
Journal of the University of Chemical Technology and Metallurgy | Year: 2012

Amorphous SiO2 known as SBA-15 (Santa Barbara Amorphous) has been synthesized mixing consecutively water solutions of poly(ethylene glycol) C3H6O.C2H4O (P123), 2M HCl and tetraethoxysilan 98 % C8H20O4Si (TEOS) at 60°C. The mixture has been dried at 100°C and calcinated at 500°C. The synthesizedSBA-15 samples have been characterized by X-ray diffraction(XRD), FTIR spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and N2 physisorption analysis. The Ti-SBA-15 has been prepared by impregnation using a solution of Ti-isoporopoxide in isopropanol with different concentrations (1, 5, 10, 15, 25 mass %). During the impregnation TiO2 nanoparticles have been incorporated into theSBA-15 hexagonal channels. N2-adsorption/desorption analysis has been carried out to investigate the specific surface area, pore size and pore diameter of Ti-SBA-15 to be used as a DME catalyst.

Ikramova Z.A.,Tashkent Institute of Chemical Technology | Mukhamedzhanova M.T.,Tashkent Institute of Chemical Technology
Glass and Ceramics (English translation of Steklo i Keramika) | Year: 2010

The results of investigations of the phase compositions and formation of the microstructure of ceramic sintered samples based on the composition kaolin-fireclay-KTMO for the purpose of obtaining ceramic materials with elevated physical chemical properties are presented. © 2010 Springer Science+Business Media, Inc.

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