Iranian Journal of Chemistry and Chemical Engineering
Volume:24 Issue: 2, Mar-Apr 2005

The cost of drying carpet which is done toward the end of the manufacturing process, is quite high. The carpet industry has been using convection drying for many years. Little attention has been given to quantifying the effect of microwave power during the drying of carpet. An experimental system was developed whereby air was introduced into the cavity of a domestic microwave oven. The results indicated that microwave power levels and sample specifications are the most important parameters, with statistically significant effects on the drying constants

A new carbazole – containing polymer has been synthesized for further photophysical studies. Efficient synthesis of the substituted methyl methacrylate has been accomplished via microwave assisted synthesis of 1-chloro-4-carboxy- 5,6,7,8- tetrahydrocarbazole followed by further steps, such as reduction of the 4-substituted methyl carboxylate, dechlorination of the ring and at last, the reaction of the 4-hydroxymethyl –9- ethyl carbazole with methacryloyl chloride. The resulting monomer was then polymerized free-radically to form the polymer, having a distribution Mw/Mn of 2.6.

Electrochemical behavior of the new mono and dinuclear Co (III) complexes of the types trans-[pyCo((DO)(DOH)pn)(L)]PF6 and [{py Co((DO)(DOH)pn)}2 (μ-dicyd)] (PF6)2 have been studied in acetonitrile solution. All the mono nuclear complexes show two quasi- reversible reduction couples associate to Co(III/II)and Co(II/I). Each of these redox couples split to two one electron waves in dinuclear complex.

[Ru(terpy)(bpy)(L)]PF6 complexes, where terpy is 2,2΄:6′,2″– terpyridine, bpy is 2,2΄-bipyridine and L is monoanions of 4-bromophenylcyanamide (4-Brpcyd), 4-methoxyphenylcyanamide (4-MeOPcyd), 2,4-dibromophenylcyanamide(2,4-Br2pcyd), 2,4-dimethylphenylcyanamide (2,4-Me2pcyd), 2-methylphenyl- cyanamide (2-MePcyd), phenylcyanamide (Pcyd) and naphtylcyanamide (ncyd) have been prepared and characterized by elemental analysis, IR, 1H-NMR and UV-vis spectroscopies and cyclic voltammetry. Spectroelectrochemistry was used to generate the electronic absorption spectra of the Ru(III) complexes, [Ru(terpy)(bpy)(L)]2+ in acetonitrile solution. The spectral data associated with the Ru(III)-cyanamido LMCT chromophore were compared to those derived from Ru(III) analogues in order to gain a greater understanding the effect of spectator ligands on the nature of the Ru(III)-Cyanamide bond.The data supports greater covalency in the Ru(III)-cyanamide bond of [Ru(terpy)(bpy)(L)]2+ complexes compared to their Ru(III) analogues.

Micro silica (MS) is an extremely fine, spherical powder that is used as an additive for improving concrete performance. It is obtained as a by product of silicon metal and ferrosilicon alloy production. Due to its pozzolanic nature, micro silica can be used to enhance the qualities of both fresh and hardened concrete. Addition of micro silica into the concrete as a cement replacement, decreases its permeability. As a result, it forms very dense and chemically durable concrete to withstand the harsh and corrosive chemical environments. The results of detailed investigations on concrete made from type V cement with additions of micro silica as replacement of part of cement and cured in tap water showed dramatic increase on compressive strength (CS) of concrete after 7 days of hydration onwards. By repeated experiment in sodium sulfate solutions prepared under ASTM C1012 requirements, the results are the same as tap water but the extend of increase of compressive strength is lower. It also is confirmed by the results that micro silica modifies the pore size distribution of concrete made with type V cement as well as its permeability in the same trend that has been previously reported in the literature for ordinary Portland cement. By replacing of part of type V cement with micro silica in concrete composition a very chemically durable and high strength concrete forms which is suitable for using in the harsh chemical environments such as marine and offshore structures or the places where the concentration of sulfate ions are high, such as concrete sewage pipe line networks.

Compound N2, N3, N7, N8, 1, 4, 5, 6, 9, 10-decaphenyltetradecahydrodipyrazino [2, 3-b: 2, 3-e] pyrazine-2, 3, 7, 8-tetraamine (4) was prepared by condensation of 1, 1′, 2, 2′-tetrakis (phenylamino) ethane (1d) and glyoxal in EtOH or i-PrOH. Also, reaction of 1d with glyoxal in equimolare in EtOH resulted 5,6-bis (ethoxy)-N2, N3, 1, 4-tetraphenylhexahydro-2, 3-pyrazinediamine (5). The natures of products are sensitive to acidity, temperature and solvent. In acidic media, 4 and 5 are unstable and degraded to diimine 6.

Steady state and dynamic fermentations of bakers yeast in molasses based media were analyzed in a laboratory scale bioreactor. Sugar and biomass balances together with the Monod biokinetics were used to develop the process model. Parameters of the model were obtained using collected experimental data. Model predicted open loop responses to step changes in feed concentration as well as dilution rate were compared with experimental data and a good agreement was observed. Despite the nonlinear nature of pH in a biological system, it was controlled successfully using a special on-off strategy implemented on a personal computer. Results proved that productivity of the continuous process was at least twice that of the batch process.

The application of ion current signals is one of the most recent approaches in engine management systems. By applying a small constant DC voltage across the electrodes of the spark plug and measuring the current through the electrode gap, the state of gas may be measured and investigated. In this paper a computer code is developed in order to analyze the state of gas during the combustion period. It is shown that there is a strong correlation between the peak pressure and the maximum current position. It is also shown that among all combustion products, the NO has the most contribution in generating electrical current. The two zones model is used for calculating the cylinder pressure and temperature.

Separation of ten sedative- hypnotic drugs was performed by RP-HPLC using mixed micellar mobile phase. Effect of temperature, type and amount of organic modifier in mobile phase on efficiency (N) and asymmetry factor (B/A) showed that, the appropriate conditions for a good separation were 35°C and 7% (V/V) butanol in mobile phase. Variations of selectivity factor versus butanol concentration, Mixture of SDS/ Brij- 35 concentrations and pH of mobile phase showed that the appropriate conditions were 7%(V/V), 15 mM SDS +1.0mM Brij-35 and pH=3 in mobile phase respectively.