Authors:A. Zahia, F. Salhi, A. Pineau, and G. Moya
The results of isothermal calorimetric determination of the stored energy for 99.999% pure polycrystalline rolled silver are reported. The stored energy values were found to be linearly related to the recrystallization temperature. An explanation of this effect is given in terms of the specific heat difference between the rolled and annealed states.
Authors:Agus Pramono, Klodian Dhoska, Irida Markja, and Lembit Kommel
The pressing of equal channel angular pressing - parallel channel process has an effect on microstructure and mechanical properties of the composite materials. Finite element has been used for conducting pressure effect through parallel channel for knowing distribution effect pressing. The materials AA1070 and AA6061 powder matrix composite with Al2O3 nano fiber were used as reinforcement. Mechanical properties and scanning electron microscope were observed in room temperature pressure and in case where the temperatures were higher than recrystallization value. Both results were compared to determine the effectiveness of pressure on each process. The characterization of aluminum composites on the aspects and phenomena of the distribution of pressing effect on hot and cold conditions treasured by finite elements will be explained in this paper.
DA-5018 is a new capsaicin derivative and has analgesic effect. The objective of this work was to investigate the existence
of polymorphs and pseudopolymorphs of DA-5018 and the transformation of crystal forms. Eight crystal forms of DA-5018 have
been isolated by recrystallization and characterized by powder X-ray diffractometry (PXRD), differential scanning calorimetry
(DSC), and thermogravimetric analysis (TG).
The PXRD and DSC patterns of the eight crystal forms were different respectively.
In the dissolution studies in simulated intestinal fluid at 37±0.5°C, the solubility of Form 2 was the highest. And the solubility
in water decreased in rank order: Form 2>Form 3>Form 1>Form 5>Form 7>Form 4>Form 6>Form 8.
Eight crystal forms were shown to have a good physical stability at room temperature for 60 days.
Authors:H. Enginar, P. Ünak, F. Yurt, and F. Zümrüt Biber
An oestrogen derivative 3,17-a-oestradiolyl propyl 1,4,8,11-tetraazacyclotetradecanyl-1-(4-methylbenzoic acid)ester (ESTCPTA) that is 3,17-a-oestradiolyl propinol coupled to 1-(4-methylbenzoic acid)1,4,8,11-tetraazacyclotetradecane (CPTA) was synthesized in five steps. The product was purified by recrystallization in ethyl alcohol, and analysed by NMR and IR spectroscopy. ESTCPTA was labeled with 99mTc and radio thin layer chromatography (RTLC) and radio-paper electrophoresis were used to determine the radiochemical yields. Specific activity was approximately 23.7 GBq/mmol and the labeling yield was over 95%. The biodistribution studies were performed on female Albino Wistar rats. The rats were sacricified by ether narcotization at certain time intervals and the activity of the organs was counted by a gamma counter. The activity per gram tissue was calculated and time activity curves were generated.
Authors:T. Tsukame, M. Kutsuzawa, H. Sekine, H. Saitoh, and Y. Shibasaki
A forensic sample consisting of melt-recrystallized polymers that was recovered from the scene of a fire in a factory was identified by differential scanning calorimetry. The factory commonly used two kinds of film sheets, A and B, made by different manufacturers. It was necessary to decide whether the forensic sample related to material A or B. The forensic sample and reference samples of materials A and B were subjected to infrared spectroscopy and pyrolysis gas chromatograph mass spectrometry measurements, which revealed their polyethylene nature. The thermal behaviour of the samples was examined by differential scanning calorimetry (DSC) and they were found to be blends of two kinds of polyethylenes, low-density polyethylene and linear low-density polyethylene. The samples could be identified and distinguished from each other via the DSC measurements.
A survey is given on the basic factor affecting the determination of90Sr in milk and bones by removal of the excess calcium by precipitation. Strong co-precipitation of calcium and strontium takes
place using fuming nitric acid, potassium hexacyano-ferrate, EDTA, ethanol-ether mixture and butanol-(1) due to partial precipitation,
recrystallization and adhesion processes where thepH value of the environment plays an improtant role. The obtained results show very limited applicability of these agents for
the determination of90Sr in biological materials because of low accuracy and reproducibility. This conclusion is especially valid for the method
of rapid determination of90Sr with EDTA according toWelford andSutton. In this work a method is given for the determination of90Sr in milk and bones using potassium hexacyanoferrate.
Authors:J. Van den Brande, Ilse Weuts, G. Verreck, J. Peeters, M. Brewster, and G. Van den Mooter
Thermal analysis was performed on the anti-HIV agent loviride in order to test its suitability to be processed using hot-melt
extrusion. Temperature characteristic parameters of crystallization were determined to quantify the stability of amorphous
loviride. The present study has shown that cooling and heating loviride at different rates influenced its thermal stability.
At high cooling rates melted loviride did not crystallize during cooling, and formed a glass that recrystallized during reheating.
Very low cooling rates resulted in significant decomposition of the drug. The glass transition temperature was found to increase
as a function of increasing heating rates and the activation energy for the transition from the glassy to the super-cooled
liquid state was relatively high, indicating good stability of the glass.
The effect of the dyeing on the melting behavior of poly(lactic acid) fabrics was investigated by differential scanning calorimeter.
The DSC melting peaks at 10C min-1 of the untreated poly(lactic acid) fabric were observed at a temperature higher than those of the dyed fabrics. The restricting
force from the extended tie molecules along the fiber axis seems to decrease in the dyeing process. When the sample was rapidly
heated, the crystallites melted at lower temperatures since recrystallization was restricted. It was estimated, based on the
heating-rate dependency of melting behavior, that the original crystallites of the untreated sample melted at 146.1C and
those of the dyed samples melted at higher temperatures, suggesting that their crystallites are grown to be more perfect in
the dyeing process.
The studies were devoted to determination of the effect of gas atmosphere and its pressure on the second step of decomposition
of hydrated titanium dioxide (HTD) promoted by sulfate groups.
It has been found that thermal decomposition of HTD at temperatures above 300C consists of a number of processes such as
dehydroxylation, desulfuration, recrystallization and sintering of solid grains, photochemical processes (if the decomposition
proceeds in the presence of light) and adsorption of gas phase components (in the presence of air or SO2).
Kinetic parameters characterizing this step of decomposition have been determined for processes carried out in vacuum and
in argon or air atmospheres (at a pressure of 13.33hPa). The kinetic curves of decomposition carried out in the presence of
gases capable of being adsorbed on the surface of partly dehydrated HTD are featured by local extrema due to simultaneous
processes of decomposition and adsorption of gas components.
Carrier-free strontium and cesium isotopes were used to study the heterogeneous exchange of the systems strontium/strontium
carbonate and cesium/cesium tetraphenylborate. The elements under consideration are among the long-lived isotopes most desired
to be removed from waste solutions and consequently the use of heterogeneous exchange as an applied phenomenon for selective
fixation is possible. The results obtained show that the above two systems are unstable ones (i. e., undergoing either formation
or dissolution of the precipitated solid phase). New modified equations were proposed for quantitative calculation of the
fraction of exchange, using only radiometric data and avoiding the use of microanalytical data. The equations are useful for
all unstable systems, especially if no precise microquentitative method of analysis is known for the element under consideration.
Recrystallization and self-diffusion were proposed to explain the two parts characterizing the exchange curves.