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Trimethoprim
Abstracts
181
The Ionic Conductance of Mono and Divalent Cations in Single Crystal Layer Structure Aluminosilicates. M. Stanley Whittingham, Schlumberger-Doll Research. USA
ing from tetragonal superstructure of maghemite with increasing Al-substitution reveals the break in ordering of octahedral vacancies in the 7(Fe,Al)203 lattice.
Clays and the cations they c o n t a i n p l a y are an important role in the diagenesis of rock formations and in physical measurements aimed at characterizing formations for mineral or oil content. To understand this behavior better a study has been made of the ionic mobility of cations in the bilayer hydrate of vermiculite. Unlike previous studies on layered aluminosilicates these measurements were made on single crystals, so that surface conductance would be minimal. It was found that cation charge was not the dominant factor in determining the magnitude of the conductivity, but that the separation of the silicate structural building blocks appeared to dominate. In addition, the preexponential factor in the diffusion equation: D = Doexp-H/RT, was anomalously large, ~ 5 cm2/sec. This is probably due to a large entropy of motion (>15 cals/mole/K) associated with the loss of bonded waters in the cation solvation sphere during the diffusional process. The conductivity at 25°C was found to vary from 3 x 10.4 to 1 x i0 -6 S/cm for sodium and magnesium respectively, much lower than for sodium in .~-alumina (1.4 x 10 -2 S/cm). The reasons for this low overall conductivity will be discussed together with the impact of the water content on the mobility of the cations.
The Conductivity of (PEO)xCa(NO3)2(Lil)y
The Vacancy Ordering and Distribution of AluminvLm Ions in y-(Fe,AD~O3 Emilia Wolska, University Poznan, Poland and Udo Schwertmann, Tech. Univ. Munich, FRG The effect of aluminum substitution on the structure of maghemite (v-Fe203) was studied by x-ray diffraction and infra-red spectroscopy. It was found that the miscibility between y-A1203 and y-Fe203 is limited to 10mol% Al. The distribution of aluminum ions in tetrahedral and octahedrai sites is about 20% and 80% of total Al-content respectively. The decreasing iv.tensity of x-ray reflecfion,~ ,'~,d~-
Rongjian Xue, Institute of Physics, P. R. China The conductivity of the poly(ethylene oxide)(PEO)double salt complexes have been measured. The preparation of samples was accomplished by using Ca(NO3)2.4H20 melt as the solvent and then dewatering. The highest conductivity appears in (PEO)10Ca(NO3)22Lil amorphous material. The other samples, corresponding to x=20 and 30 for y=0 and x=10 and y=2 are crystallineand theirconductivities vs. temperature follow the Arrhenius equation. All of these samples can be formed as rubbery films.
Solid State Interaction Study on the System Polyvinylpyrrolidone frrimethoprim T. Zerlia, Stazione Sperimentale Combustibili, A. Marini, V. Berbenni, V. Massarotti, F. Giordano, A. La Manna (Pavia), G. P. Bet:~netti (Firenze) and C. Margheritis, (Messina)~ Italy. The interaction between cross-linked poiyvinylpyrrolidone (PVP-XL) and Trimethoprim TMP has been studied by DSC.. SEM: FTIR/PAS. DSC measurements ~h~,w thai ~'ery different thermal traces are obtained on ground and not ground mixtures suggesti ~g that some dramatic ck,a~,ges take piacc as a consequence of components co-grinding. This idea is confirmed by SEM analysis which shows striking differences between the two types of mixture. FTIR/PAS measurements- on the contrary, give very similar spectra on both ground and not ground mixtures showing that from a spectroscopic point of view components co-grinding does not exert any particular effect. An explanation is proposed of these at first sight ~nfiicting rcsults and, based on spectroscopic data~ an interaction model is suggeste4.
181
The Ionic Conductance of Mono and Divalent Cations in Single Crystal Layer Structure Aluminosilicates. M. Stanley Whittingham, Schlumberger-Doll Research. USA
ing from tetragonal superstructure of maghemite with increasing Al-substitution reveals the break in ordering of octahedral vacancies in the 7(Fe,Al)203 lattice.
Clays and the cations they c o n t a i n p l a y are an important role in the diagenesis of rock formations and in physical measurements aimed at characterizing formations for mineral or oil content. To understand this behavior better a study has been made of the ionic mobility of cations in the bilayer hydrate of vermiculite. Unlike previous studies on layered aluminosilicates these measurements were made on single crystals, so that surface conductance would be minimal. It was found that cation charge was not the dominant factor in determining the magnitude of the conductivity, but that the separation of the silicate structural building blocks appeared to dominate. In addition, the preexponential factor in the diffusion equation: D = Doexp-H/RT, was anomalously large, ~ 5 cm2/sec. This is probably due to a large entropy of motion (>15 cals/mole/K) associated with the loss of bonded waters in the cation solvation sphere during the diffusional process. The conductivity at 25°C was found to vary from 3 x 10.4 to 1 x i0 -6 S/cm for sodium and magnesium respectively, much lower than for sodium in .~-alumina (1.4 x 10 -2 S/cm). The reasons for this low overall conductivity will be discussed together with the impact of the water content on the mobility of the cations.
The Conductivity of (PEO)xCa(NO3)2(Lil)y
The Vacancy Ordering and Distribution of AluminvLm Ions in y-(Fe,AD~O3 Emilia Wolska, University Poznan, Poland and Udo Schwertmann, Tech. Univ. Munich, FRG The effect of aluminum substitution on the structure of maghemite (v-Fe203) was studied by x-ray diffraction and infra-red spectroscopy. It was found that the miscibility between y-A1203 and y-Fe203 is limited to 10mol% Al. The distribution of aluminum ions in tetrahedral and octahedrai sites is about 20% and 80% of total Al-content respectively. The decreasing iv.tensity of x-ray reflecfion,~ ,'~,d~-
Rongjian Xue, Institute of Physics, P. R. China The conductivity of the poly(ethylene oxide)(PEO)double salt complexes have been measured. The preparation of samples was accomplished by using Ca(NO3)2.4H20 melt as the solvent and then dewatering. The highest conductivity appears in (PEO)10Ca(NO3)22Lil amorphous material. The other samples, corresponding to x=20 and 30 for y=0 and x=10 and y=2 are crystallineand theirconductivities vs. temperature follow the Arrhenius equation. All of these samples can be formed as rubbery films.
Solid State Interaction Study on the System Polyvinylpyrrolidone frrimethoprim T. Zerlia, Stazione Sperimentale Combustibili, A. Marini, V. Berbenni, V. Massarotti, F. Giordano, A. La Manna (Pavia), G. P. Bet:~netti (Firenze) and C. Margheritis, (Messina)~ Italy. The interaction between cross-linked poiyvinylpyrrolidone (PVP-XL) and Trimethoprim TMP has been studied by DSC.. SEM: FTIR/PAS. DSC measurements ~h~,w thai ~'ery different thermal traces are obtained on ground and not ground mixtures suggesti ~g that some dramatic ck,a~,ges take piacc as a consequence of components co-grinding. This idea is confirmed by SEM analysis which shows striking differences between the two types of mixture. FTIR/PAS measurements- on the contrary, give very similar spectra on both ground and not ground mixtures showing that from a spectroscopic point of view components co-grinding does not exert any particular effect. An explanation is proposed of these at first sight ~nfiicting rcsults and, based on spectroscopic data~ an interaction model is suggeste4.