[en] As a result of the reaction of tryptophan with copper (II) chloride, a complex of copper tryptophan ate was obtained. The composition of the complex was studied by elemental, thermal, Χ-ray phase analysis, IR, and UV spectroscopy. The anti radical activity of the complex was studied on irradiated wheat seeds. It was revealed that the treatment of wheat seeds before irradiation with an aqueous solution of complex leads to normalization of the biosynthesis of photosynthetic pigments.

No abstract available

[en] Sugarcane bagasse was characterized by thermogravimetric analysis (TGA) with the different heating rates, and nitrogen carrier from 30 to 800℃. Through decreasing the sample's mass by temperature, the stage of thermal decomposition could be determined. Specifically, there were three stages of decomposition including moisture escape stage, decomposition of cellulose stage, hemicellulose and lignin decomposition stage. On the other hand, based on the results of TGA the activation energy of decomposition process was determined by the inverse of the Flynn-Wall-Ozawa (FWO) method and Kissinger-Akahira-Sunose (KAS) method. The calculated results were compared with the activation energy by the Coats-Redfern method and Criado method in order to find the kinetics of bagasse pyrolysis process. Accordingly, when the conversion of reaction was lower than 75 %, corresponding to the decomposing process of hemicellulose and cellulose, the thermal decomposing process of bagasse obeyed diffusion kinetics of model D₂, D₃ and D₄. (author)

[en] Styrene was polymerized for 24 h at room temperature (30°C) within different colloidal microstructures made out of fumed silica, 2,2´-azobis(isobutyronitrile) (AIBN) and aqueous solution of different cationic surfactants with varied tail length; hexyltrimethylammonium bromide (HTAB), dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB) and octadecyltrimethylammonium bromide (OTAB). Styrene in styrene/silica/CTAB showed a larger polymeric conversion (90%) compared to styrene/silica/DTAB (85%) and styrene/silica/OTAB (82%) mixtures. These polymerized styrene samples were examined using scanning electron microscopy, thermogravimetric analyzer, differential scanning calorimeter and gel-permeation chromatography. Polystyrene (PS) composites contained spherical particles with varied mean particle diameter (d). The particles in the composite became larger with increased surfactant tail length. PS/silica/OTAB particles were comparatively larger (d = 271 ± 13 nm) than PS/silica/CTAB (d = 250 ± 12 nm) and PS/silica/DTAB (d = 240 ± 12 nm) particles. Compared to silica-containing styrene mixtures with CTAB or DTAB, styrene/silica/OTAB formed PS with larger molar mass and elevated glass transition temperature, at room temperature. The molar masses and glass transition temperatures of PS obtained from PS/silica/OTAB, PS/silica/ CTAB and PS/silica/DTAB were 1279, 943, 995 kg mol^-1, and 105, 104, 102°C, respectively. The short hydrophobic tail of HTAB resulted in inconsistent styrene to PS conversions in the mixtures. (author)

[en] Full text: The technical and economic assessment of process of thermo-chemical decomposition of biomass in the processes of transformation of it in power-consuming energy/carriers by the use of the concentrated gel of sun radiation, has been considered

[en] Published in summary form only

[en] The present investigation deals with the study of untreated and alkali treated natural fibers extracted from the stem of Catharanthus roseus. The physical, chemical, crystallinity, mechanical, wettability, thermal, and surface characteristics were analyzed for untreated and alkali treated Catharanthus roseus fibers (CRFs). The results showed that chemical treatment removed excess amorphous contents such as hemicellulose, lignin and wax contents thereby there was an enhancement in tensile strength, crystalline index, and surface roughness. The char residue upon thermogravimetric analysis got increased from 25.2% to 39.6% for untreated and alkali treated CRFs respectively. The alkali treated CRF showed lesser contact angle which proved its improved wettability in the liquid phase. Thus the improvement in the characteristics of the alkali treated CRF can make it useful for developing lightweight polymer composites. (paper)

[en] Full text: The new organic ligands -N-(5-clorasalicylidine)-β-athanol (HL'1), N(-5-bromosalicyliden)-β-alanine (H₂L³), N(-2-hydroxy-5-bromobenzyl)-β-alanine (H₂L⁴), N-(5-bromosalicylidene) qlycibe (H₂L⁵) have been obtained. The new lanthanide complexes (Y, La,Ce,Nd,Sm,Er,Lu) with N-(2-hyroxy-5-brombenzyl)-β-alanine (H₂L⁴) have been prepared and studied. The elemental analyses, IR-spectra and thermo gravimetric data point out on the following composition of the obtained compounds: Ln(L)(X)(H₂O)n (where L=N-(2-hydroxy-5-brombenzil)-β-alanine (H₂L⁴), X=CH3COO-, NO3-, Br-, n=3,4). IR spectra's indicate on bi- or polynyclear structure of complexes

[en] In the present study, thermogravimetric analysis was used for investigation a bagasse pyrolysis. Multi-period models were applied for evaluation of kinetics parameter based on the TG curve. The decomposition bagasse process was undergone four periods via the breakdown of each different chemical component in a sample. The dehydration occurred below 170℃; hemicellulose primarily and cellulose partially decomposed in a range of 170 to 318℃ and cellulose continuously decomposed from 318 to 400 ℃. The temperature range of 400-700℃ for the last period showed the evidence of lignin decomposition. The study also identified activation energy constant (E_a), the pre-exponential factor (A) and reaction order (n) for each period of pyrolysis process. The dependence of the breakdown of the specific chemical bond on the pyrolysis temperature was also proven by FTIR spectrum analysis. (author)

[en] With the advancements of materials science and technology, organic materials found significant applications in aerospace industry. But under the orbital thermal and vacuum environment, organic materials can outgas and the outgassed products and induced environment often degraded performances of spacecraft or its subsystem. In this article, the typical impacts of outgassing environment on spacecraft are explained briefly. Then the outgassing theory, test method, identification of compounds and control measures were reviewed in detail. The need for transient and long-term outgassing model is discussed. The standard test methods of E595 and E1559 are compared. The promising new techniques such as infrared spectrometry and/or mass-spectrometry with thermogravimetric analysis is proposed for the identification of outgassed compounds. The vacuum bakeout and molecular absorber for outgassing control are reviewed and for the last more research work is needed. (paper)