NANOSTRUCTURAL MATERIALS AND ELECTROCHEMICAL NANOSTRUCTURAL SURFACE TREATMENT
(Review)
Tz. Tzvetkoff
Chemical Technology
FIXATION OF REACTIVE DYES USING MICROWAVE IRRADIATION
A. K. Haghi
CONDENSATION OF HETEROAROMATIC ALDEHYDES WITH MELDRUM’S ACID TO PRODUCTS OF PHARMACEUTICAL INTEREST
A. Bijev, P. Prodanova
EFFECT OF WATER ON THE VULCANIZATION OF FILLED STYRENE-BUTADIENE RUBBER. PART I
M. Ivanov1, D. Ivanova2
EFFECT OF WATER ON THE ACCELERATED SULPHUR-THIAZOLE AND SULPHUR-THIURAM VULCANIZATION OF STYRENE-BUTADIENE RUBBER. PART II
M. Ivanov1, D. Ivanova2
SUPERADSORPTIVE POLYACRYLONITRILE FIBROUS MATERIALS
V. Angelova, L. Boyadjieva, S. Veleva, R. Garvanska
Metallurgy
THERMODYNAMIC STUDY OF THE Ag-Au-Me (Me=Zn,Sn) TERNARY LEAD-FREE SOLDER ALLOYS*
D. Živkovic, D. Manasijevic, Ž. Živkovic
Chemical Engineering
OPTIMAL DESIGN OF A MULTIPLE CONCENTRIC-TUBE HEAT EXCHANGER
I. Seikova, I. Pentchev
INVESTIGATION OF THE MICROWAVE PROPERTIES OF THE SYSTEM
MgTiO3-CaTiO3-Ba(Mg1/3Ta2/3)O3
V. Parvanova, I. Iliev
PLATING AND PROPERTIES OF ELECTRODEPOSITED ZINC-TIN ALLOY COATINGS
I. Todorov1, G. Raichevski2
PHASE CHANGES DURING LASER HEATING OF THIN Zn FILMS DEPOSITED ON GaP
D. Demireva
Chemistry
SYNERGISTIC SOLVENT EXTRACTION OF Ce (III) WITH MIXTURES OF CHELATING EXTRACTANT AND QUATERNARY AMMONIUM SALT
I. Dukov, M. Atanassova
DIELECTRIC PROPERTIES OF (1-x)BaTiO3.xMgTiO3 OBTAINED BY PEROXOMETHOD
V. Parvanova
IR SPECTROSCOPY INVESTIGATION OF METAL AMORPHOUS NANOPARTICLES
I. Markova - Deneva, K. Alexandrova, G. Ivanova, I. Dragieva
RELATIONSHIP BETWEEN THE CHEMICAL SOIL CONTENT AND THE PRESENCE OF TERMITES
G. M.Taha, M. A. Hoda
INVESTIGATION OF THE KINETICS OF AGING OF CHEMI-MECHANICAL
PULP FROM POPLAR WOOD
E. Valcheva, R. Boeva, E. Petkova, Z. Litovski
Mathematics
FORMATION OF THE SUPPORT PROBLEM IN THE OPTIMIZATION ALGORITHM FOR DYNAMIC SYSTEMS WITH TERMINAL CONSTRAINTS IN A CLASS OF INERTIAL CONTROLS
L. Dimitrova

NANOSTRUCTURAL MATERIALS AND ELECTROCHEMICAL NANOSTRUCTURAL SURFACE TREATMENT
(Review)
Tz. Tzvetkoff

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: tzvetkof@uctm.edu

Received 16 March 2004
Acepted 22 March 2004

A literature survey on nanotreatment and nanomodification of surfaces is presented. A generalized classification of the nanomaterials types is shown. The basic mechanical method for nanomodification-scanning probe lithography (SPL) in its three varieties: mechanical, electric and optical is considered. Particular attention is directed to the rapidly developing electrochemical methods for surface nanomodification. These are the scanning tunelling microscopy (STM) and the atomic force microscopy (ATM). Based on the literature review prognoses are made for the basic trends of future investigations. It is suggested that the nanomodification of metal, semiconducting and isolating surfaces aiming to create nanostructures of properties set in advance will be the most important one. In this connection the author begins a series of studies on the treatment of iron and nickel alloys of wide practical application. The kinetic modelling of the processes and the elucidation of their mechanism are the main objectives.
Keywords: nanomaterials, nanomodification, kinetic modelling, electrochemical mechanism.

Chemical Technology

FIXATION OF REACTIVE DYES USING MICROWAVE IRRADIATION
A. K. Haghi

The University of Guilan, P.O.Box 3756, Rasht, IRAN
E-mail: haghi@guilan.ac.ir

Received 07August 2003
Accepted 08 September 2003

Microwave energy has been used to increase the fixation rate of reactive dyes on cotton fabric in pad-batch dyeing. The results show that the colour strength was superior to those of dyeing by conventional methods.
Keywords: reactive dye, microwave irradiation, fixation rate.

CONDENSATION OF HETEROAROMATIC ALDEHYDES WITH MELDRUM’S ACID TO PRODUCTS OF PHARMACEUTICAL INTEREST
A. Bijev, P. Prodanova

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: a.bijev@uctm.edu

Received11 February 2004
Accepted 15 March 2004

Seven heteroaromatic aldehydes, namely 1H-pyrrole-2-carbaldehyde; 5-formyl-3-methyl-1H-pyrrole-2,4-dicarboxylic acid diethyl ester; 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester; 4-formyl-2,5-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester, 4-formyl-3,5-dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester; 1-acetyl-1H-indole-3-carbaldehyde, and thiophene-2-carbaldehyde have been condensed with 2,2-dimethyl-[1,3]dioxane-4,6-dione, popular as Meldrum’s acid. Because of the high C-H acidity of Meldrum’s acid, the reaction takes place at ambient temperature and in the absence of any basic catalyst with yields in the range of 85-90%.
The new products are of pharmaceutical interest, but can also be perspective as versatile intermediates for further synthesis of new heterocyclic systems.The evaluation of the pharmacological profile, resulting from the combination of the participating heterocycles, is in progress and will be the object of a separate publication.
The structure of the new compounds has been proved by their H1-NMR and IR-spectra, whose interpretation is represented.
Keywords: Meldrum’s acid, pyrrole aldehydes, condensation, synthesis.

EFFECT OF WATER ON THE VULCANIZATION OF FILLED STYRENE-BUTADIENE RUBBER. PART I
M. Ivanov1, D. Ivanova2

1 University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: ezek@uctm.edu
2 University of National and World Economy
Department of Commodity Science
Stud. grad “H. Botev”, 1700 Sofia, Bulgaria
E-mail: danielai@unwe.acad.bg

Received 18 February 2004
Accepted 08 March 2004

The effect of water on the sulphur-thiazole vulcanization of styrene-butadiene rubber was investigated. The vulcanization curves and the kinetic parameters of the rubber compositions filled with three types of carbon black (K 345, N 324 and FT) with different chemical surface activity as well as those of unfilled rubber compositions were studied.
It was established that the presence of water in quantity 3 phr caused an increase of the rate of vulcanization and decrease of the activation energy of vulcanization which was observed also for the unfilled rubber compositions.
Keywords: rubber, vulcanization, carbon black, sulphur-thiazole, water, activation energy.

EFFECT OF WATER ON THE ACCELERATED SULPHUR-THIAZOLE AND SULPHUR-THIURAM VULCANIZATION OF STYRENE-BUTADIENE RUBBER. PART II
M. Ivanov1, D. Ivanova2

Received 18 February 2004
Accepted 08 March 2004

The effect of water /3 phr/ on the unactivated and activated by zinc oxide and stearic acid sulfur-thiazole, thiazole, sulphur-thiuram and thiuram vulcanization of styrene-butadiene rubber filled with carbon black is investigated.
It is established that the presence of water in the rubber compositions results in the decrease of the activation energy of vulcanization in all cases. For the activated sulphur-thiazole and thiazole vulcanization the decrease of the activation energy is connected also to the increase of the density of the vulcanization net. During sulphur-thiuram vulcanization the presence of water does not change or changes slightly the density of the vulcanization net while during the activated thiuram vulcanization the presence of water causes a high decrease of the density of the vulcanization net. An attempt is made for the explanation of the mechanism of water action.
Keywords: rubber, vulcanization, carbon black, sulphur-thiazole, water, activation energy.

SUPERADSORPTIVE POLYACRYLONITRILE FIBROUS MATERIALS
V. Angelova, L. Boyadjieva, S. Veleva, R. Garvanska

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: garvanska@uctm.edu

Received 17 December 2003
Accepted 05 February 2004

An effective method for obtaining superadsorptive fibrous materials by chemical modification of polyacrylonitrile (PAN) fibres in autoclave system with alkali and formaldehyde was developed.
Modelling and optimisation of process was performed using model based approach to Taguchi method of quality improvement. Optimal conditions for obtaining superadsorptibe capacity of PAN fibres were found. The physicochemical study of superadsorptive PAN fibrous materials by infrared and scanning electron microscopy was carried out.
Keywords: polyacrylonitrile fibres, superabsorptive fibrous materials, basic hydrolysis, formaldehyde, model based approach.

THERMODYNAMIC STUDY OF THE Ag-Au-Me (Me=Zn,Sn) TERNARY LEAD-FREE SOLDER ALLOYS*
D. Živkovic, D. Manasijevic, Ž. Živkovic

University of Belgrade,
Technical VJ 12, 19210 Bor, Serbia and Montenegro
E-mail: jmm@eunet.yu
Received 15 January 2004
Accepted 10 February 2004

The results of predicting of thermodynamic properties for Ag-Au-based ternary lead-free solders: Ag-Au-Zn and Ag-Au-Sn alloys, using the general solution model are presented in this paper. Values for the integral molar quantities - Gibbs excess energies and integral molar enthalpies of mixing, as well as the activities for all three constituent components in the investigated ternary systems, were predicted and compared with existing experimental literature data.
Keywords: thermodynamics, predicting, GSM, ternary systems, Ag-Au-Zn, Ag-Au-Sn.

Chemical Engineering

OPTIMAL DESIGN OF A MULTIPLE CONCENTRIC-TUBE HEAT EXCHANGER
I. Seikova, I. Pentchev

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: seikova@uctm.edu

Received 26 November 2003
Accepted 18 February 2004

A piston flow model for steady-state heat transfer in a multiple concentric-tube heat exchanger was derived in order to predict temperature profiles in all of the annular regions. The model was solved numerically and compared to the available analytical solutions in a particular case of triple-tube exchanger.
Uniform heat capacity flow rates distribution related to design drawings and flow regime appeared as a determining factor to assess the optimum heat exchanger area. As a result of the more evenly distributed driving force, the difference between the exit temperatures of all of the cooling or respectively - heating streams decreases and the modeling may be reduced to the classical double-tube heat exchanger calculation. The derived considerations have been validated on simulations and experiments for an industrial-scale triple-tube heat exchanger.
Keywords: multiple concentric-tube heat exchangers, optimal design, distributed parameter model, analytical solution.

INVESTIGATION OF THE MICROWAVE PROPERTIES OF THE SYSTEM
MgTiO3-CaTiO3-Ba(Mg1/3Ta2/3)O3
V. Parvanova, I. Iliev

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail:vparvanova@uctm.edu

Received 05 February 2004
Accepted 15 March 2004

The system ?1MgTiO3-?2CaTiO3-?3Ba(Mg1/3Ta2/3)O3 was synthesized and studied. Simplex lattice plans were used to determine the maximum value of the quality factor Q at a sufficiently high value of the relative permittivity ?r. Research was carried out in the region limited by 0.3?X1?0.9, 0.05?X2?0.4 and 0.05?X3?0.3 at sintering temperature, T=1450°C. Compositions with ?r varying from 24 to 82 and Q factor varying from 2881 to 4501 at a frequency f0 = 10 GHz can be synthesized in the studied region. The composition 0.9MgTiO3.0.05CaTiO3.0.05Ba(Mg1/3Ta2/3)O3 is found with Q = 4501, ?r = 24 and ?f = 0 ppm°C-1. The latter could be used successfully for production of dielectric microwave resonators for the satellite television.
Keywords: Microwave dielectric materials, MgTiO3-CaTiO3-Ba(Mg1/3Ta2/3)O3.

PLATING AND PROPERTIES OF ELECTRODEPOSITED ZINC-TIN ALLOY COATINGS
I. Todorov1, G. Raichevski2

1Sofia University D. Zankov str. 8, Sofia-1164
E-mail: todorov@biofac.uni-sofia.bg
2Bulgarian Academy of Sciences

Received 21 October 2003
Accepted 17 March 2004

All shortcomings of electrodeposited zinc, cadmium or tin coatings, can be avoided significantly , if zinc-tin alloy coatings are used, naturally in different ratio formulations depending on the concrete technical requirements. For this we are used electrolyte from Na2ZnO2, Na2SnO3 and additive. The additive is a complex compound ensuring stabilizing and wetting effects, as well as levelling and throwing power of the electrolyte. It’s examine current yield, tin content in the alloy, internal stress, throwing power and anodic behaviour.
Keywords: electrodeposition, Zn-Sn alloy coatings, current yield, internal stress, throwing power, anodic behaviour.

PHASE CHANGES DURING LASER HEATING OF THIN Zn FILMS DEPOSITED ON GaP
D. Demireva

Technical University-Gabrovo,
4 Hadji Dimitar St., 5300 Gabrovo, Bulgaria,
E-mail: didem@tugab.bg

Received 19 February 2004
Accepted 15 March 2004

Structural changes in the undersurface layer of GaP, caused by the laser irradiation of the structure Zn thin film – GaP substrate are presented in the paper. X-ray and electron diffraction patterns are used as investigating tools. Inclusions of Zn with crystal structure are observed in the undersurface layer of GaP, but inclusions neither of Ga, nor of ZnP2 and Zn3P2, whose phases exist on the phase diagram Zn-GaP have not been estimated. The formation of Zn inclusions is explained with the high velocity of crystallization, which is characteristic for the laser treatment.
Keywords: structure, laser irradiation, inclusions.

SYNERGISTIC SOLVENT EXTRACTION OF Ce (III) WITH MIXTURES OF CHELATING EXTRACTANT AND QUATERNARY AMMONIUM SALT
I. Dukov, M. Atanassova

University of Chemical Technology and Metallurgy Kl. Ohridski 8, Blvd., 1756 Sofia, Bulgaria
E-mail: dukov@yahoo.com

Received April 2002 Accepted 28 May 2002

The influence of the quaternary ammonium salt anion on the synergistic extraction of Ce (III) with mixtures of thenoyltrifluoroacetone (HTTA) and 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HP) and Aliquat 336 as synergistic agent in chloride (QCl) and perchlorate (QClO4) forms in C6H6 has been studied. The formation of mixed anionic complexes of type Q+[Ln(TTA)4]- and Q+[LnP4]- have been determined. The values of the equilibrium constants have been calculated. It was found that the change of the anion of the salt from Cl- to ClO4- exerted a considerable influence on the metal extraction.
Keywords: Synergistic extraction, lanthanoids, thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, quaternary ammonium salt.

DIELECTRIC PROPERTIES OF (1-x)BaTiO3.xMgTiO3 OBTAINED BY PEROXOMETHOD
V. Parvanova

University of Chemical Technology and Metallurgysize Kl. Ohridski 8, Blvd., 1756 Sofia, Bulgaria
E-mail:vparvanova@hotmail.com

Received 3 July 2002
Accepted 26 July 2002

The system (1-x)BaTiO3.xMgTiO3 (x=0,1; 0,2; 0,3 and 0,4 mol at.) is obtained by peroxometod. Temperature dependence of the permittivity (er) and dielectric losses (tgd) at frequency 1 kHz from calcination temperatures of ceramics Tcal = 1250, 1300 and 1400°C are studied. Ceramic material with compound 0,6BaTiO3.0,4MgTiO3 calcinated at 1400°C have TKer ® 0 for temperature interval - 40 to 140°C, er = 3500, and low dielectric losses tgd = 35.10-4. Those values make it suitable for production of thermal stability capacitors as well as capacitors with low dielectric losses working at high frequencies.
Keywords: Titanates, (1-x)BaTiO3.xMgTiO3, dielectric properties

IR SPECTROSCOPY INVESTIGATION OF METAL AMORPHOUS NANOPARTICLES
I. Markova - Deneva, K. Alexandrova*, G. Ivanova*, I. Dragieva*

University of Chemical Technology and Metallurgy Kl. Ohridski 8, Blvd., 1756 Sofia, Bulgaria
E-mail:vania@uctm.edu
*Central Laboratory of the Electrochemical Power Sources,Bulgarian Academy of Sciences, 1113 Sofia

Received 4 May 2002
Accepted 10 October 2002

IR spectroscopy investigations of metal amorphous nanoparticles with composition such as (M1, M2)xByHz (where M1 and M2 may be Co, Fe, Li, Mg, Sm) in a wide frequency region of 4000 - 400 cm -1 on IR Spectrophotometer with Fourier transformation (Bruker EQUINOX 55) have been carried out. The IR spectra of the (Li, Fe)xByHz nanoparticles, synthesized by the T - method, and prepared with and without the presence of a hydrophobic agent have been taken. An IR spectroscopy study of the amorphous (Co, M)xByHz nanoparticles (where M = Fe, Li, Mg, Sm) and (Li, Fe)xByHz particles prepared by the Y method as well as of ( Li, Fe)xByHz particles, prepared by the T - method has been performed too. The IR spectra of MH electrodes based on these nanoparticles have been taken down before and after an implementation of charge - discharge tests as electrodes (a positive pole) in 6M KOH electrolyte in a Ni - MH electric battery. The creation of chemical bonds between boron and oxygen atoms and the formation of BO3 and BO4 groups has been proved. The hydrophobic agent used during the borohydride reduction process has limited the access of the oxygen from the surroundings and the possibility of Fe and Li to be oxidized and has stimulated the formation of BO3 groups. The electrochemical tests in a KOH electrolyte of the MH electrodes based on the metal nanoparticles investigated have proved the creation of chemical bonds between boron and oxygen atoms in BO3 and BO4 groups and between metal and oxygen in complex metal oxides as well as the presence of O - H bonds in free and linked OH groups and in adsorbed molecules of H2O on the MH electrode surface.
Keywords: infrared spectra, (Co, M)xByHz and ( Li, Fe)xByHz nanoparticles, borohydride reduction process, Ni - MH electrodes

RELATIONSHIP BETWEEN THE CHEMICAL SOIL CONTENT AND THE PRESENCE OF TERMITES
G. M.Taha*, M. A. Hoda**

*Chemistry Department, Aswan Faculty of Science, South Valley University, Aswan, Egypt,
E-mail: gmtaha@hotmail.com
**Zoology Department, Aswan Faculty of Science, South Valley University, Aswan, Egypt Received 21 May 2002
Accepted 12 June 2002

Unprecedented trials were performed to find a relationship between the physicochemical characteristics, major and trace element content of a soil and the existence of termites under its surface "at 40 cm depth". For this purpose, twenty soil samples under the roots of both the infested and sound trees "ten each" were collected from Kima district, Aswan, Egypt. All the collected samples were analyzed for pH, conductivity, organic matter (OM), loss on ignition (LOI), Ca, Cl, CO32-, HCO3-, Mg, NO-2 and NO-3 content in the soil:water extract. The acids mixture containing HCl, HNO3 and HF was used for the complete attack of the samples. The resulting clear solutions were analyzed for Cd, Co, Cr, Cu, Fe, K, Mn, Pb and Zn content. The resulting data were then statistically treated.
Keywords: soil insect pests, wood eating insects, capillary pore space, non-capillary pore space.

INVESTIGATION OF THE KINETICS OF AGING OF CHEMI- MECHANICAL PULP FROM POPLAR WOOD
E. Valcheva, R. Boeva, E. Petkova, Z. Litovski

University of Chemical Technology and MetallurgyKl. Ohridski 8, Blvd., 1756 Sofia, Bulgaria Received 18 October 2002
Accepted 28 October 2002

Aging of high yield fiber materials is a complicated physico-chemical process which depends on a lot of factors: temperature, time, humidity and oxygen presence, irradiation, etc. As a result of aging the optical and physico-mechanical properties of the materials are degraded. The kinetics of aging of chemi-mechanical pulp (CMP) from poplar wood is examined in this paper. Samples from unbleached and bleached with hydrogen peroxide and sodium hydrosulfite CMP which have been subjected to artificial thermal aging at temperatures of 363, 378 and 393 K are used. The change in the brightness W(%) is traced.
It is found out that the kinetics of the process is best described by an exponential kinetic equation, which is applicable to processes taking place over an energetically uniformly inhomogeneous surface. The values of the heterogeneous coefficient are computed and is determined that it slightly depends on the temperature and the method of CMP bleaching. The values of the activation energy and the pre-exponential factor are determined. The presence of a compensatory effect is ascertained. The presence of general a compensatory effect in the process of aging of various samples of CMP shows that the method of bleaching does not influence the process mechanism.
Keywords: chemi-mechanical pulp, bleaching, hydrogen peroxide, hydrosulfite, aging, pre-exponential factor.

University of Chemical Technology and Metallurgy,
8 Kl. Ohridski, 1756 Sofia, Bulgaria
E-mail: ldimitrova@uctm.edu

Received 29 January 2004
Accepted 22 March 2004

In the problem of the terminal control if the termination procedure [4] finishes with the construction of a suboptimal control then the solution of the problem is complete. Otherwise, the process continues with the procedure for formation and analysis of the solution of the support problem, starting with , (sp- support).
In the present work the procedure for formation of a new support problem is considered. The composed problem is linear. We solve the problem by using the dual method of the linear optimization [5].
Keywords: optimization, dynamic systems, inertial controls, maximum principal, support, support control.