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Dettagli della rivista
Formato
Rivista
eISSN
1899-4741
Pubblicato per la prima volta
03 Jul 2007
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

Volume 16 (2014): Edizione 3 (September 2014)

Dettagli della rivista
Formato
Rivista
eISSN
1899-4741
Pubblicato per la prima volta
03 Jul 2007
Periodo di pubblicazione
4 volte all'anno
Lingue
Inglese

Cerca

20 Articoli
access type Accesso libero

Polyurethane Foams with Pyrimidine Rings

Pubblicato online: 03 Oct 2014
Pagine: 1 - 6

Astratto

Abstract

Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

Parole chiave

  • barbituric acid
  • glycidol
  • alkylene carbonates
  • oligoetherols
  • polyurethane foams
  • thermal stability
access type Accesso libero

Effect of Apple and Rosehip Pomaces on Colour, Total Phenolics and Antioxidant Activity of Corn Extruded Snacks

Pubblicato online: 03 Oct 2014
Pagine: 7 - 11

Astratto

Abstract

Extrusion cooking technology was applied for obtaining corn extrudates fortified with various level (10-20%) of rosehip pomace powder or apple pomace powder. The total polyphenols content, antioxidant activities (ABTS), organoleptic properties and colour of the extrudates were determined.

Pomace addition increased the level of total polyphenols content and antioxidant activity in obtained corn - pomace extrudates, especially in samples enriched with rosehip pomace. Extrudates with 20% of rosehip pomace addition characterized the highest polyphenols content and antioxidant activity. Only the slight decrease of some quality features - shape and size, taste and fl avour, structure and colour of obtained extrudates was observed. Sample with fruit pomace addition showed increasing consistency evaluation. The extruded products by utilising fruit by-products got good evaluation of panelists and can be an excellent source of bioactive compounds in the daily human diet.

Parole chiave

  • apple pomace
  • rosehip pomace
  • extrusion
  • polyphenols
  • antioxidant activity
access type Accesso libero

Anchoring Tri(8-Quinolinolato)Iron Onto Sba-15 for Partial Oxidation of Benzyl Alcohol Using Water as the Solvent

Pubblicato online: 03 Oct 2014
Pagine: 12 - 17

Astratto

Abstract

Tri(8-quinolinolato)iron complex immobilized onto SBA-15 catalyst has been synthesized through a stepwise procedure. The characterization results indicated that the BET surface area, total pore volume and average pore width decrease after stepwise modification of SBA-15, while the structure keeps intact. Catalytic tests showed that FeQ3-SBA-15 catalyzes the oxidation reaction well with 34.8% conversion of benzyl alcohol and 74.7% selectivity to benzaldehyde when water is used as the solvent after 1 h reaction. In addition, homogeneous catalyst tri(8-quinolinolato)iron exhibits very bad catalytic behavior using water as the solvent.

Parole chiave

  • SBA-15
  • 8-quinolinol
  • iron
  • benzyl alcohol
  • benzaldehyde
access type Accesso libero

The Influence of Technological PVD Process Parameters on the Topography, Crystal and Molecular Structure of Nanocomposite Films Containing Palladium Nanograins

Pubblicato online: 03 Oct 2014
Pagine: 18 - 24

Astratto

Abstract

The paper describes the preparation and characteristics of films composed of Pd nanograins placed in carbonaceous matrix. Films were obtained in PVD (Physical Vapor Deposition) process from two sources containing: the first one - fullerene powder and the second one - palladium acetate. The topographical, morphological and structural changes due to different parameters of PVD process were studied with the use of Atomic Force Microscopy and Scanning Electron Microscopy, whereas the structure was studied with the application of the Transmission Electron Microscopy and Fourier Transform Infrared Spectroscopy methods. It was shown that topographical changes are connected with the decomposition ratio of Pd acetate as well as the form of carbonaceous matrix formed due to this decomposition. Palladium nanograins found in all films exhibit the fcc structure type and their diameter changes from 2 nm to 40 nm depending on the PVD process parameters.

Parole chiave

  • palladium
  • carbon
  • SEM
  • AFM
  • TEM
  • FTIR
access type Accesso libero

Interaction of SiO2 Nanoparticles with Seed Prechilling on Germination and Early Seedling Growth of Tall Wheatgrass (Agropyron Elongatum L.)

Pubblicato online: 03 Oct 2014
Pagine: 25 - 29

Astratto

Abstract

The effect of six SiO2 nanosized concentrations (0, 5, 20, 40, 60 and 80 mg L-1) and three seed prechilling treatments (control, seed prechilling before nano SiO2 treatments, treatments of seed with nano SiO2 before prechilling) on germination and seedling growth of tall wheatgrass (Agropyron elongatum L.) were studied. Results indicated that application of SiO2 nanoparticles significantly increased seed germination of tall wheatgrass from 58 percent in control group to 86.3 and 85.7 percent in 40 and 60 mg L-1, respectively. Applying SiO2 nanoparticles increased dry weight of shoot, root and seedling of tall wheatgrass. Increasing concentration of nanoparticle from 0 up to 40 mg L-1 increased seedling weight around 49 percent compared to the control, nevertheless decreased under 60 and 80 mg L-1 treatments. In conclusion, seed prechilling in combination with SiO2 nanoparticles largely broke the seed dormancy for A. elongatum.

Parole chiave

  • seed treatment
  • seed prechilling
  • germination rate
  • nanoparticle
access type Accesso libero

Nitrogen-Phosphorous Fertilizers on the Base of Concentrated Ammonium Nitrate Solution and Central Kyzylkum Phosphate Raw Material

Pubblicato online: 03 Oct 2014
Pagine: 30 - 35

Astratto

Abstract

This article presents obtaining of nitrogen-phosphate fertilizers by reacting ordinary phosphate powder from Central Kyzylkum (Uzbekistan) with 70-90% ammonium nitrate solution at 100ºС. Chemical composition of the fertilizers was determined fully. Relevant consistence of acceptable forms of Р2О5 and СаО in the product extremely decreased by the increase of amount of phosphate raw material (PRM) in reaction mixture. The addition of phosphate additive into ammonium nitrate solution significantly increases toughness of ammonium nitrate granules and their growth velocity proportionally by phosphate powder added. Herewith, initial concentration of ammonium nitrate did not effect practically on the granule’s toughness. It is described that, phosphate additive decreases the speed of solubility of ammonium nitrate granules almost up to 1.83 times. On our opinion, decrease of fertilizer solubility is the result of growing phosphorite share in the products. The more is the phosphorite share, the more slowly dissolution process of the fertilizer granule does occur.

Parole chiave

  • ammonium nitrate solution
  • phosphate raw material
  • activation
  • nitrogen phosphorous fertilizer
  • toughness of granules
  • velocity of granules dissolution
access type Accesso libero

Simplified Mashing Efficiency. Novel Method for Optimization of Food Industry Wort Production with the Use of Adjuncts

Pubblicato online: 03 Oct 2014
Pagine: 36 - 39

Astratto

Abstract

Malt extracts and malt concentrates have a broad range of application in food industry. Those products are obtained by methods similar to brewing worts. The possible reduction of cost can be achieved by application of malt substitutes likewise in brewing industry. As the malt concentrates for food industry do not have to fulfill strict norms for beer production it is possible to produce much cheaper products. It was proved that by means of mathematic optimization it is possible to determine the optimal share of unmalted material for cheap yet effective production of wort.

Parole chiave

  • mathematic optimization
  • mashing efficiency
  • wort production
  • malt concentrates for food industry
access type Accesso libero

Fabrication of Electrochemical Nanoelectrode for Sensor Application Using Focused Ion Beam Technology

Pubblicato online: 03 Oct 2014
Pagine: 40 - 44

Astratto

Abstract

The capabilities and applications of the focused ion beam (FIB) technology for detection of an electrochemical signal in nanoscale area are shown. The FIB system, enabling continuous micro- and nanofabrication within only one equipment unit, was used to produce a prototype of electrochemical nanometer-sized electrode for sensor application. Voltammetric study of electrochemically active compound (ferrocenemethanol) revealed the diffusion limiting current (12 pA), corresponding to a disc (planar) nanoelectrode with about 70 nm diameter of contact area. This size is in a good accordance with the designed contact-area (50 nm × 100 nm for width × thickness) of the FIB-produced nanoelectrode. It confirms that produced nanoelectrode is working properly in liquid solution and may enable correct measurements in nanometer-sized regions.

Parole chiave

  • FIB nanotechnology
  • nanosensor
  • electrochemistry
access type Accesso libero

A Study on Damage to PLA Knitted Fabrics During Scouring and Bleaching

Pubblicato online: 03 Oct 2014
Pagine: 45 - 50

Astratto

Abstract

Ingeo® PLA (polylactic acid) knitted fabric was scoured through an exhaust technique. The scouring was carried out with sodium carbonate in the presence of a detergent at various concentrations and temperatures. The scoured fabric was bleached with various oxidative bleaching agents. Bleaching was carried out with hydrogen peroxide, sodium chlorite and sodium hypochlorite. Hydrogen peroxide was applied by exhaust and cold pad batch (CPB) techniques. It was observed that during scouring PLA fabric was degraded at high alkali concentrations and processing temperatures. The scouring temperature above 60ºC proved to be deleterious due to the scouring solution penetrating into the polymer structure and damaged the fiber. Sodium chlorite and sodium hypochlorite caused little damage to the mechanical properties of PLA. Hydrogen peroxide when applied by the CPB technique did not reduce strength appreciably but when applied by the exhaust technique decreased the strength significantly. SEM analysis revealed that hydrogen peroxide caused holes and slit formation in the fiber structure.

Parole chiave

  • PLA
  • Scouring
  • Bleaching
  • Weight loss
  • Mechanical properties
  • SEM
access type Accesso libero

Reducing of on Polymerization Shrinkage by Application of UV Curable Dental Restorative Composites

Pubblicato online: 03 Oct 2014
Pagine: 51 - 55

Astratto

Abstract

This manuscript describes dental compositions contain in-organic fillers, multifunctional methacrylates and photoinitiators. The main problem by application and UV curing process is the shrinkage of photoreactive dental materials during and after UV curing process. Total shrinkage of UV curable dental composites is a phenomenon of polymerization shrinkage, typical behavior for multifunctional methacrylates during polymerization process. The important factors by curing of dental composites are: kind and concentration of used methacrylates, their functionality, double bond concentration, kind and concentration of added photoinitiator and UV dose. They are investigated UV-curable dental compositions based on 2,2-bis-[4-(2-hydroxy-3-methacryxloyloxypropyl)phenyl]propane (Bis-GMA) and containing such multifunctional monomers as 1,3-butanediol dimethacrylate (1,3-BDDMA), diethylene glycol dimethacrylate (DEGDMA), tetraethylene glycol dimethacrylate (T3EGDMA), trimethylolpropane trimethacrylate (TMPTMA), polyethylene glycol 200 dimethacrylate (PEG200DA). Reduction of polymerization shrinkage of dental compositions is at the moment a major problem by dental technology.

Parole chiave

  • dental compositions
  • polymerization shrinkage
  • multifunctional methacrylates
  • UV-curing
access type Accesso libero

Flue Gas Desulfurization by Mechanically and Thermally Activated Sodium Bicarbonate

Pubblicato online: 03 Oct 2014
Pagine: 56 - 62

Astratto

Abstract

This paper presents the results of study on structural parameters (particle size, surface area, pore volume) and the sorption ability of mechanically and thermally activated sodium bicarbonate. The sorption ability of the modified sorbent was evaluated by: partial and overall SO2 removal efficiency, conversion rate, normalized stoichiometric ratio (NSR). Sodium bicarbonate was mechanically activated by various grinding techniques, using three types of mills: fluid bed opposed jet mill, fine impact mill and electromagnetic mill, differing in grinding technology. Grounded sorbent was thermally activated, what caused a significant development of surface area. During the studies of SO2 sorption, a model gas with a temperature of 300°C, of composition: sulfur dioxide at a concentration of 6292 mg/mn3, oxygen, carbon dioxide and nitrogen as a carrier gas, was used. The best development of surface area and the highest SO2 removal efficiency was obtained for the sorbent treated by electromagnetic grinding, with simultaneous high conversion rate.

Parole chiave

  • flue gas desulfurization
  • sodium bicarbonate
  • surface area
  • conversion rate
access type Accesso libero

Modified and Unmodified Zinc Oxide as Coagent in Elastomer Compounds

Pubblicato online: 03 Oct 2014
Pagine: 63 - 68

Astratto

Abstract

The aim of this work was to study the activity of unmodified and modified ZnO in the peroxide crosslinking of hydrogenated acrylonitrile-butadiene elastomer (HNBR) and ethylene-propylene copolymer (EPM). In the first step, zinc oxide was obtained by emulsion precipitation. Maleic acid was introduced onto the surface of ZnO using an in situ method. The unmodified and modified zinc oxide was characterized using dispersive and morphological analysis, BET surface area analysis, and elemental, spectroscopic and thermal analysis. In the second stage of the research, the ZnO/MA systems were incorporated into the structure of elastomer compounds improving the kinetic and mechanical properties of vulcanizates. The proposed modification method had a favorable effect on the physicochemical properties of the zinc oxide and on the kinetic and mechanical properties of the vulcanizates. This study demonstrated that modification of zinc oxide by maleic acid is a promising technique.

Parole chiave

  • zinc oxide
  • maleic acid
  • emulsion precipitation
  • modification
  • elastomers
  • vulcanizates
access type Accesso libero

Single Pot Benzylation of O-Xylene with Benzyl Chloride and Benzyl Alcohol Over Pillared Montmorillonites

Pubblicato online: 03 Oct 2014
Pagine: 69 - 73

Astratto

Abstract

Improvement of product selectivity is a major concern of the day. Presence of a coreactant can alter the rate as well as product selectivity of many key reactions like Friedel-Crafts benzylation. Single pot benzylation of o-xylene with benzyl chloride and benzyl alcohol was studied over transition metal exchanged pillared clay catalysts. Complete conversion of benzyl alcohol occured within one hour with 100% monoalkylated product selectivity. The reaction of o-xylene with benzyl alcohol was found to proceed fast in presence of benzyl chloride in single pot, than when present alone as the benzylating species. This enhancement occurs at the expense of no reaction of benzyl chloride, which when present alone reacts faster than benzyl alcohol. Existence of a second transition metal exchanged between the pillars increased the rate of the reaction. A detailed investigation of the reaction variables suggested preferential adsorption of benzyl alcohol to catalyst active sites as the reason.

Parole chiave

  • Friedel-Crafts benzylation
  • single pot benzylation
  • pillared clays
access type Accesso libero

Future Applications of Apricot (Prunus Armeniaca Kaisa) ß Galactosidase in Dairy Industry

Pubblicato online: 03 Oct 2014
Pagine: 74 - 79

Astratto

Abstract

The present study demonstrates the immobilization of β galactosidase from apricots (Prunus armeniaca kaisa) on an inexpensive concanavalin A layered cellulose-alginate hybrid gel. Immobilized β galactosidase retained 78% of the initial activity after crosslinking by glutaraldehyde. It exhibited greater fraction of activity at both acidic and basic pH, and showed broad spectrum temperature optimum as compared to free enzyme. Moreover, immobilized enzyme exhibited higher thermal stability at 60°C and retained 80% of the original enzyme activity in presence of 3% galactose. The crosslinked immobilized enzyme showed improved hydrolysis of lactose from milk and whey in batch processes at 50°C as well as in continuous reactors operated at fl ow rate of 20 mL/h and 30 mL/h even after one month. Moreover, crosslinked adsorbed β galactosidase retained 76% activity even after its sixth repeated use, thereby promoting its use for lactose hydrolysis in various dairy products even for longer durations.

Parole chiave

  • Apricots
  • β galactosidase
  • lactose hydrolysis
  • dairy industries
access type Accesso libero

Processes and Technologies for the Recycling of Spent Fluorescent Lamps

Pubblicato online: 03 Oct 2014
Pagine: 80 - 85

Astratto

Abstract

The growing industrial application of rare earth metals led to great interest in the new technologies for the recycling and recovery of REEs from diverse sources. This work reviews the various methods for the recycling of spent fluorescent lamps. The spent fluorescent lamps are potential source of important rare earth elements (REEs) such as: yttrium, terbium, europium, lanthanum and cerium. The characteristics of REEs properties and construction of typical fl uorescent lamps is described. The work compares also current technologies which can be utilized for an efficient recovery of REEs from phosphors powders coming from spent fluorescent lamps. The work is especially focused on the hydrometallurgical and pyrometallurgical processes. It was concluded that hydrometallurgical processes are especially useful for the recovery of REEs from spent fluorescent lamps. Moreover, the methods used for recycling of REEs are identical or very similar to those utilized for the raw ores processing.

Parole chiave

  • fluorescent lamps
  • recycling
  • rare earth elements
  • hydrometallurgical process
  • pyrometallurgical process
  • solvent extraction
  • leaching
access type Accesso libero

Dehydrochlorination of 1,3-Dichloropropan-2-Ol by Calcium and Sodium Hydroxide Solutions

Pubblicato online: 03 Oct 2014
Pagine: 86 - 90

Astratto

Abstract

The results of dehydrochlorination of 88 wt% aqueous solution of 1,3-dichloropropan-2-ol to epichlorohydrin are reported. The process was carried out in the reaction-stripping column system with a continuous removal of epichlorohydrin in the steam stream. Aqueous solutions of sodium and calcium hydroxides at concentrations in the range of 3-14 wt% were used for the dehydrochlorination. The infl uence of the type and concentration of dehydrochlorination agent on 1,3-dichloropropan-2-ol conversion, the selectivity of transformation to epichlorohydrin and by-products, and the composition of distillate and wastewater were studied.

Parole chiave

  • epichlorohydrin
  • dehydrochlorination
  • dichloropropanols
  • 1,3-dichloropropan-2-ol
access type Accesso libero

Co(Salen) Catalysed Oxidation of Synthetic Lignin-Like Polymer: Naoh Effects

Pubblicato online: 03 Oct 2014
Pagine: 91 - 96

Astratto

Parole chiave

  • Co(salen)
  • catalyst
  • catalytic oxidation
  • lignin model polymer
  • NaOH effect
  • FTIR
  • C-13 NMR
  • GC-MS
access type Accesso libero

The Formation of Polycomplexes of Poly(Methyl Vinyl Ether-Co-Maleic Anhydride) and Bovine Serum Albumin in the Presence of Copper Ions

Pubblicato online: 03 Oct 2014
Pagine: 97 - 105

Astratto

Abstract

The binary and ternary complex formations of poly(methyl vinyl ether-co-maleic anhydride) (PMVEMA) with copper ions and with bovine serum albumin (BSA) in the presence of copper ions in phosphate buffer solution at pH = 7 were examined by the techniques of UV-visible, fluorescence, dynamic light scattering, atomic force microscopy measurements. In the formation of binary complexes of PMVEMA-Cu(II), the addition of copper ions to the solution of PMVEMA in phosphate buffer solution at pH = 7 forms homogeneous solutions when the molar ratio of Cu(II)/MVEMA is 0.5. Then the formations of ternary complexes of PMVEMA-Cu(II)-BSA were examined. Study analysis revealed that the toxicities of polymer-metal and polymer-metal-protein mixture solutions depend on the nature and ratio of components in mixtures.

Parole chiave

  • polyelectrolyte
  • bovine serum albumin
  • copper ions
  • metal complexes
  • biological processes
  • biomaterials
access type Accesso libero

The Impact of Dry Mass Content in Pig Liquid Manure on its Treatment with a Filtration Method

Pubblicato online: 03 Oct 2014
Pagine: 106 - 110

Astratto

Abstract

The present study examines the impacts of dry mass content in pig liquid manure on its treatment with a filtration method. Samples of liquid manure with variable dry mass content were subjected to treatment using phosphoric acid, sulfuric acid, lime milk and superphosphate, as well as to thermal treatment, while in the last phase of pressure filtration. Increased dilution of the manure resulted in a reduced raw materials consumption ratio and improved filtration process efficiency, which ranged from 408 to 3765 kg/m2/h. The highest filtration efficiency was achieved using manure containing 3% dry mass, while the lowest efficiency was observed in manure at 10% dry mass. The increase in liquid manure dilution also reduced chemical oxygen demand in the filtrate, which ranged from 15 062 to 3656 mg/l. An appropriate manure dilution level, under the constant parameters of the treatment process, reduced phosphorus content in the filtrate to < 10 mg/kg while simultaneously enriching the post-filtration sediment with this precious fertilizing component.

Parole chiave

  • pig manure treatment
  • filtration method
  • dry mass
  • filtrate
access type Accesso libero

Nanosilver: A Catalyst in Enzymatic Hydrolysis of Starch

Pubblicato online: 03 Oct 2014
Pagine: 111 - 113

Astratto

Abstract

Silver nanoparticles are widely used, because of their antimicrobial properties. In this paper, the rate of starch digestion in the presence of nanocatalyst was compared with the rate of reaction without nanosilver. The rate of enzymatic degradation of starch was found to be increased in the presence of silver nanoparticles. It is considered that α-amylase was immobilized onto the surface of nanoparticles.

Parole chiave

  • nanocatalyst
  • starch degradation
  • nanosilver
20 Articoli
access type Accesso libero

Polyurethane Foams with Pyrimidine Rings

Pubblicato online: 03 Oct 2014
Pagine: 1 - 6

Astratto

Abstract

Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

Parole chiave

  • barbituric acid
  • glycidol
  • alkylene carbonates
  • oligoetherols
  • polyurethane foams
  • thermal stability
access type Accesso libero

Effect of Apple and Rosehip Pomaces on Colour, Total Phenolics and Antioxidant Activity of Corn Extruded Snacks

Pubblicato online: 03 Oct 2014
Pagine: 7 - 11

Astratto

Abstract

Extrusion cooking technology was applied for obtaining corn extrudates fortified with various level (10-20%) of rosehip pomace powder or apple pomace powder. The total polyphenols content, antioxidant activities (ABTS), organoleptic properties and colour of the extrudates were determined.

Pomace addition increased the level of total polyphenols content and antioxidant activity in obtained corn - pomace extrudates, especially in samples enriched with rosehip pomace. Extrudates with 20% of rosehip pomace addition characterized the highest polyphenols content and antioxidant activity. Only the slight decrease of some quality features - shape and size, taste and fl avour, structure and colour of obtained extrudates was observed. Sample with fruit pomace addition showed increasing consistency evaluation. The extruded products by utilising fruit by-products got good evaluation of panelists and can be an excellent source of bioactive compounds in the daily human diet.

Parole chiave

  • apple pomace
  • rosehip pomace
  • extrusion
  • polyphenols
  • antioxidant activity
access type Accesso libero

Anchoring Tri(8-Quinolinolato)Iron Onto Sba-15 for Partial Oxidation of Benzyl Alcohol Using Water as the Solvent

Pubblicato online: 03 Oct 2014
Pagine: 12 - 17

Astratto

Abstract

Tri(8-quinolinolato)iron complex immobilized onto SBA-15 catalyst has been synthesized through a stepwise procedure. The characterization results indicated that the BET surface area, total pore volume and average pore width decrease after stepwise modification of SBA-15, while the structure keeps intact. Catalytic tests showed that FeQ3-SBA-15 catalyzes the oxidation reaction well with 34.8% conversion of benzyl alcohol and 74.7% selectivity to benzaldehyde when water is used as the solvent after 1 h reaction. In addition, homogeneous catalyst tri(8-quinolinolato)iron exhibits very bad catalytic behavior using water as the solvent.

Parole chiave

  • SBA-15
  • 8-quinolinol
  • iron
  • benzyl alcohol
  • benzaldehyde
access type Accesso libero

The Influence of Technological PVD Process Parameters on the Topography, Crystal and Molecular Structure of Nanocomposite Films Containing Palladium Nanograins

Pubblicato online: 03 Oct 2014
Pagine: 18 - 24

Astratto

Abstract

The paper describes the preparation and characteristics of films composed of Pd nanograins placed in carbonaceous matrix. Films were obtained in PVD (Physical Vapor Deposition) process from two sources containing: the first one - fullerene powder and the second one - palladium acetate. The topographical, morphological and structural changes due to different parameters of PVD process were studied with the use of Atomic Force Microscopy and Scanning Electron Microscopy, whereas the structure was studied with the application of the Transmission Electron Microscopy and Fourier Transform Infrared Spectroscopy methods. It was shown that topographical changes are connected with the decomposition ratio of Pd acetate as well as the form of carbonaceous matrix formed due to this decomposition. Palladium nanograins found in all films exhibit the fcc structure type and their diameter changes from 2 nm to 40 nm depending on the PVD process parameters.

Parole chiave

  • palladium
  • carbon
  • SEM
  • AFM
  • TEM
  • FTIR
access type Accesso libero

Interaction of SiO2 Nanoparticles with Seed Prechilling on Germination and Early Seedling Growth of Tall Wheatgrass (Agropyron Elongatum L.)

Pubblicato online: 03 Oct 2014
Pagine: 25 - 29

Astratto

Abstract

The effect of six SiO2 nanosized concentrations (0, 5, 20, 40, 60 and 80 mg L-1) and three seed prechilling treatments (control, seed prechilling before nano SiO2 treatments, treatments of seed with nano SiO2 before prechilling) on germination and seedling growth of tall wheatgrass (Agropyron elongatum L.) were studied. Results indicated that application of SiO2 nanoparticles significantly increased seed germination of tall wheatgrass from 58 percent in control group to 86.3 and 85.7 percent in 40 and 60 mg L-1, respectively. Applying SiO2 nanoparticles increased dry weight of shoot, root and seedling of tall wheatgrass. Increasing concentration of nanoparticle from 0 up to 40 mg L-1 increased seedling weight around 49 percent compared to the control, nevertheless decreased under 60 and 80 mg L-1 treatments. In conclusion, seed prechilling in combination with SiO2 nanoparticles largely broke the seed dormancy for A. elongatum.

Parole chiave

  • seed treatment
  • seed prechilling
  • germination rate
  • nanoparticle
access type Accesso libero

Nitrogen-Phosphorous Fertilizers on the Base of Concentrated Ammonium Nitrate Solution and Central Kyzylkum Phosphate Raw Material

Pubblicato online: 03 Oct 2014
Pagine: 30 - 35

Astratto

Abstract

This article presents obtaining of nitrogen-phosphate fertilizers by reacting ordinary phosphate powder from Central Kyzylkum (Uzbekistan) with 70-90% ammonium nitrate solution at 100ºС. Chemical composition of the fertilizers was determined fully. Relevant consistence of acceptable forms of Р2О5 and СаО in the product extremely decreased by the increase of amount of phosphate raw material (PRM) in reaction mixture. The addition of phosphate additive into ammonium nitrate solution significantly increases toughness of ammonium nitrate granules and their growth velocity proportionally by phosphate powder added. Herewith, initial concentration of ammonium nitrate did not effect practically on the granule’s toughness. It is described that, phosphate additive decreases the speed of solubility of ammonium nitrate granules almost up to 1.83 times. On our opinion, decrease of fertilizer solubility is the result of growing phosphorite share in the products. The more is the phosphorite share, the more slowly dissolution process of the fertilizer granule does occur.

Parole chiave

  • ammonium nitrate solution
  • phosphate raw material
  • activation
  • nitrogen phosphorous fertilizer
  • toughness of granules
  • velocity of granules dissolution
access type Accesso libero

Simplified Mashing Efficiency. Novel Method for Optimization of Food Industry Wort Production with the Use of Adjuncts

Pubblicato online: 03 Oct 2014
Pagine: 36 - 39

Astratto

Abstract

Malt extracts and malt concentrates have a broad range of application in food industry. Those products are obtained by methods similar to brewing worts. The possible reduction of cost can be achieved by application of malt substitutes likewise in brewing industry. As the malt concentrates for food industry do not have to fulfill strict norms for beer production it is possible to produce much cheaper products. It was proved that by means of mathematic optimization it is possible to determine the optimal share of unmalted material for cheap yet effective production of wort.

Parole chiave

  • mathematic optimization
  • mashing efficiency
  • wort production
  • malt concentrates for food industry
access type Accesso libero

Fabrication of Electrochemical Nanoelectrode for Sensor Application Using Focused Ion Beam Technology

Pubblicato online: 03 Oct 2014
Pagine: 40 - 44

Astratto

Abstract

The capabilities and applications of the focused ion beam (FIB) technology for detection of an electrochemical signal in nanoscale area are shown. The FIB system, enabling continuous micro- and nanofabrication within only one equipment unit, was used to produce a prototype of electrochemical nanometer-sized electrode for sensor application. Voltammetric study of electrochemically active compound (ferrocenemethanol) revealed the diffusion limiting current (12 pA), corresponding to a disc (planar) nanoelectrode with about 70 nm diameter of contact area. This size is in a good accordance with the designed contact-area (50 nm × 100 nm for width × thickness) of the FIB-produced nanoelectrode. It confirms that produced nanoelectrode is working properly in liquid solution and may enable correct measurements in nanometer-sized regions.

Parole chiave

  • FIB nanotechnology
  • nanosensor
  • electrochemistry
access type Accesso libero

A Study on Damage to PLA Knitted Fabrics During Scouring and Bleaching

Pubblicato online: 03 Oct 2014
Pagine: 45 - 50

Astratto

Abstract

Ingeo® PLA (polylactic acid) knitted fabric was scoured through an exhaust technique. The scouring was carried out with sodium carbonate in the presence of a detergent at various concentrations and temperatures. The scoured fabric was bleached with various oxidative bleaching agents. Bleaching was carried out with hydrogen peroxide, sodium chlorite and sodium hypochlorite. Hydrogen peroxide was applied by exhaust and cold pad batch (CPB) techniques. It was observed that during scouring PLA fabric was degraded at high alkali concentrations and processing temperatures. The scouring temperature above 60ºC proved to be deleterious due to the scouring solution penetrating into the polymer structure and damaged the fiber. Sodium chlorite and sodium hypochlorite caused little damage to the mechanical properties of PLA. Hydrogen peroxide when applied by the CPB technique did not reduce strength appreciably but when applied by the exhaust technique decreased the strength significantly. SEM analysis revealed that hydrogen peroxide caused holes and slit formation in the fiber structure.

Parole chiave

  • PLA
  • Scouring
  • Bleaching
  • Weight loss
  • Mechanical properties
  • SEM
access type Accesso libero

Reducing of on Polymerization Shrinkage by Application of UV Curable Dental Restorative Composites

Pubblicato online: 03 Oct 2014
Pagine: 51 - 55

Astratto

Abstract

This manuscript describes dental compositions contain in-organic fillers, multifunctional methacrylates and photoinitiators. The main problem by application and UV curing process is the shrinkage of photoreactive dental materials during and after UV curing process. Total shrinkage of UV curable dental composites is a phenomenon of polymerization shrinkage, typical behavior for multifunctional methacrylates during polymerization process. The important factors by curing of dental composites are: kind and concentration of used methacrylates, their functionality, double bond concentration, kind and concentration of added photoinitiator and UV dose. They are investigated UV-curable dental compositions based on 2,2-bis-[4-(2-hydroxy-3-methacryxloyloxypropyl)phenyl]propane (Bis-GMA) and containing such multifunctional monomers as 1,3-butanediol dimethacrylate (1,3-BDDMA), diethylene glycol dimethacrylate (DEGDMA), tetraethylene glycol dimethacrylate (T3EGDMA), trimethylolpropane trimethacrylate (TMPTMA), polyethylene glycol 200 dimethacrylate (PEG200DA). Reduction of polymerization shrinkage of dental compositions is at the moment a major problem by dental technology.

Parole chiave

  • dental compositions
  • polymerization shrinkage
  • multifunctional methacrylates
  • UV-curing
access type Accesso libero

Flue Gas Desulfurization by Mechanically and Thermally Activated Sodium Bicarbonate

Pubblicato online: 03 Oct 2014
Pagine: 56 - 62

Astratto

Abstract

This paper presents the results of study on structural parameters (particle size, surface area, pore volume) and the sorption ability of mechanically and thermally activated sodium bicarbonate. The sorption ability of the modified sorbent was evaluated by: partial and overall SO2 removal efficiency, conversion rate, normalized stoichiometric ratio (NSR). Sodium bicarbonate was mechanically activated by various grinding techniques, using three types of mills: fluid bed opposed jet mill, fine impact mill and electromagnetic mill, differing in grinding technology. Grounded sorbent was thermally activated, what caused a significant development of surface area. During the studies of SO2 sorption, a model gas with a temperature of 300°C, of composition: sulfur dioxide at a concentration of 6292 mg/mn3, oxygen, carbon dioxide and nitrogen as a carrier gas, was used. The best development of surface area and the highest SO2 removal efficiency was obtained for the sorbent treated by electromagnetic grinding, with simultaneous high conversion rate.

Parole chiave

  • flue gas desulfurization
  • sodium bicarbonate
  • surface area
  • conversion rate
access type Accesso libero

Modified and Unmodified Zinc Oxide as Coagent in Elastomer Compounds

Pubblicato online: 03 Oct 2014
Pagine: 63 - 68

Astratto

Abstract

The aim of this work was to study the activity of unmodified and modified ZnO in the peroxide crosslinking of hydrogenated acrylonitrile-butadiene elastomer (HNBR) and ethylene-propylene copolymer (EPM). In the first step, zinc oxide was obtained by emulsion precipitation. Maleic acid was introduced onto the surface of ZnO using an in situ method. The unmodified and modified zinc oxide was characterized using dispersive and morphological analysis, BET surface area analysis, and elemental, spectroscopic and thermal analysis. In the second stage of the research, the ZnO/MA systems were incorporated into the structure of elastomer compounds improving the kinetic and mechanical properties of vulcanizates. The proposed modification method had a favorable effect on the physicochemical properties of the zinc oxide and on the kinetic and mechanical properties of the vulcanizates. This study demonstrated that modification of zinc oxide by maleic acid is a promising technique.

Parole chiave

  • zinc oxide
  • maleic acid
  • emulsion precipitation
  • modification
  • elastomers
  • vulcanizates
access type Accesso libero

Single Pot Benzylation of O-Xylene with Benzyl Chloride and Benzyl Alcohol Over Pillared Montmorillonites

Pubblicato online: 03 Oct 2014
Pagine: 69 - 73

Astratto

Abstract

Improvement of product selectivity is a major concern of the day. Presence of a coreactant can alter the rate as well as product selectivity of many key reactions like Friedel-Crafts benzylation. Single pot benzylation of o-xylene with benzyl chloride and benzyl alcohol was studied over transition metal exchanged pillared clay catalysts. Complete conversion of benzyl alcohol occured within one hour with 100% monoalkylated product selectivity. The reaction of o-xylene with benzyl alcohol was found to proceed fast in presence of benzyl chloride in single pot, than when present alone as the benzylating species. This enhancement occurs at the expense of no reaction of benzyl chloride, which when present alone reacts faster than benzyl alcohol. Existence of a second transition metal exchanged between the pillars increased the rate of the reaction. A detailed investigation of the reaction variables suggested preferential adsorption of benzyl alcohol to catalyst active sites as the reason.

Parole chiave

  • Friedel-Crafts benzylation
  • single pot benzylation
  • pillared clays
access type Accesso libero

Future Applications of Apricot (Prunus Armeniaca Kaisa) ß Galactosidase in Dairy Industry

Pubblicato online: 03 Oct 2014
Pagine: 74 - 79

Astratto

Abstract

The present study demonstrates the immobilization of β galactosidase from apricots (Prunus armeniaca kaisa) on an inexpensive concanavalin A layered cellulose-alginate hybrid gel. Immobilized β galactosidase retained 78% of the initial activity after crosslinking by glutaraldehyde. It exhibited greater fraction of activity at both acidic and basic pH, and showed broad spectrum temperature optimum as compared to free enzyme. Moreover, immobilized enzyme exhibited higher thermal stability at 60°C and retained 80% of the original enzyme activity in presence of 3% galactose. The crosslinked immobilized enzyme showed improved hydrolysis of lactose from milk and whey in batch processes at 50°C as well as in continuous reactors operated at fl ow rate of 20 mL/h and 30 mL/h even after one month. Moreover, crosslinked adsorbed β galactosidase retained 76% activity even after its sixth repeated use, thereby promoting its use for lactose hydrolysis in various dairy products even for longer durations.

Parole chiave

  • Apricots
  • β galactosidase
  • lactose hydrolysis
  • dairy industries
access type Accesso libero

Processes and Technologies for the Recycling of Spent Fluorescent Lamps

Pubblicato online: 03 Oct 2014
Pagine: 80 - 85

Astratto

Abstract

The growing industrial application of rare earth metals led to great interest in the new technologies for the recycling and recovery of REEs from diverse sources. This work reviews the various methods for the recycling of spent fluorescent lamps. The spent fluorescent lamps are potential source of important rare earth elements (REEs) such as: yttrium, terbium, europium, lanthanum and cerium. The characteristics of REEs properties and construction of typical fl uorescent lamps is described. The work compares also current technologies which can be utilized for an efficient recovery of REEs from phosphors powders coming from spent fluorescent lamps. The work is especially focused on the hydrometallurgical and pyrometallurgical processes. It was concluded that hydrometallurgical processes are especially useful for the recovery of REEs from spent fluorescent lamps. Moreover, the methods used for recycling of REEs are identical or very similar to those utilized for the raw ores processing.

Parole chiave

  • fluorescent lamps
  • recycling
  • rare earth elements
  • hydrometallurgical process
  • pyrometallurgical process
  • solvent extraction
  • leaching
access type Accesso libero

Dehydrochlorination of 1,3-Dichloropropan-2-Ol by Calcium and Sodium Hydroxide Solutions

Pubblicato online: 03 Oct 2014
Pagine: 86 - 90

Astratto

Abstract

The results of dehydrochlorination of 88 wt% aqueous solution of 1,3-dichloropropan-2-ol to epichlorohydrin are reported. The process was carried out in the reaction-stripping column system with a continuous removal of epichlorohydrin in the steam stream. Aqueous solutions of sodium and calcium hydroxides at concentrations in the range of 3-14 wt% were used for the dehydrochlorination. The infl uence of the type and concentration of dehydrochlorination agent on 1,3-dichloropropan-2-ol conversion, the selectivity of transformation to epichlorohydrin and by-products, and the composition of distillate and wastewater were studied.

Parole chiave

  • epichlorohydrin
  • dehydrochlorination
  • dichloropropanols
  • 1,3-dichloropropan-2-ol
access type Accesso libero

Co(Salen) Catalysed Oxidation of Synthetic Lignin-Like Polymer: Naoh Effects

Pubblicato online: 03 Oct 2014
Pagine: 91 - 96

Astratto

Parole chiave

  • Co(salen)
  • catalyst
  • catalytic oxidation
  • lignin model polymer
  • NaOH effect
  • FTIR
  • C-13 NMR
  • GC-MS
access type Accesso libero

The Formation of Polycomplexes of Poly(Methyl Vinyl Ether-Co-Maleic Anhydride) and Bovine Serum Albumin in the Presence of Copper Ions

Pubblicato online: 03 Oct 2014
Pagine: 97 - 105

Astratto

Abstract

The binary and ternary complex formations of poly(methyl vinyl ether-co-maleic anhydride) (PMVEMA) with copper ions and with bovine serum albumin (BSA) in the presence of copper ions in phosphate buffer solution at pH = 7 were examined by the techniques of UV-visible, fluorescence, dynamic light scattering, atomic force microscopy measurements. In the formation of binary complexes of PMVEMA-Cu(II), the addition of copper ions to the solution of PMVEMA in phosphate buffer solution at pH = 7 forms homogeneous solutions when the molar ratio of Cu(II)/MVEMA is 0.5. Then the formations of ternary complexes of PMVEMA-Cu(II)-BSA were examined. Study analysis revealed that the toxicities of polymer-metal and polymer-metal-protein mixture solutions depend on the nature and ratio of components in mixtures.

Parole chiave

  • polyelectrolyte
  • bovine serum albumin
  • copper ions
  • metal complexes
  • biological processes
  • biomaterials
access type Accesso libero

The Impact of Dry Mass Content in Pig Liquid Manure on its Treatment with a Filtration Method

Pubblicato online: 03 Oct 2014
Pagine: 106 - 110

Astratto

Abstract

The present study examines the impacts of dry mass content in pig liquid manure on its treatment with a filtration method. Samples of liquid manure with variable dry mass content were subjected to treatment using phosphoric acid, sulfuric acid, lime milk and superphosphate, as well as to thermal treatment, while in the last phase of pressure filtration. Increased dilution of the manure resulted in a reduced raw materials consumption ratio and improved filtration process efficiency, which ranged from 408 to 3765 kg/m2/h. The highest filtration efficiency was achieved using manure containing 3% dry mass, while the lowest efficiency was observed in manure at 10% dry mass. The increase in liquid manure dilution also reduced chemical oxygen demand in the filtrate, which ranged from 15 062 to 3656 mg/l. An appropriate manure dilution level, under the constant parameters of the treatment process, reduced phosphorus content in the filtrate to < 10 mg/kg while simultaneously enriching the post-filtration sediment with this precious fertilizing component.

Parole chiave

  • pig manure treatment
  • filtration method
  • dry mass
  • filtrate
access type Accesso libero

Nanosilver: A Catalyst in Enzymatic Hydrolysis of Starch

Pubblicato online: 03 Oct 2014
Pagine: 111 - 113

Astratto

Abstract

Silver nanoparticles are widely used, because of their antimicrobial properties. In this paper, the rate of starch digestion in the presence of nanocatalyst was compared with the rate of reaction without nanosilver. The rate of enzymatic degradation of starch was found to be increased in the presence of silver nanoparticles. It is considered that α-amylase was immobilized onto the surface of nanoparticles.

Parole chiave

  • nanocatalyst
  • starch degradation
  • nanosilver

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