Effect of solidified salts on1 3 7Cs leaching from bituminized products

The leaching rate of^{1 3 7}Cs from bituminized products was studied by leach tests conducted for two years.     

Analysis of DTA curves and calculation of kinetic data using computer technique

Principles of two computer programs useful for the evaluation of heterogeneous kinetics are described.The first program ALANTA allows to obtain the non-isothermal kinetic curve from the shape of general DTA peak using the DTA-equation derived elsewhere¹.The second program SQUEST determines the kinetic mechanism which is the most appropriate to a given non-isothermal kinetic curve and evaluates the corresponding kinetic parameters. The program decides between 19 kinetic models and uses both integral and differential methods of evaluation.     

Retention of85Sr and147Pm on insoluble hydroxides and phosphates prepared by the sol-gel procedure

Retention of strontium and promethium on hydroxides (hydrated oxides) and phosphates of iron and chromium prepared by the sol-gel method was studied. The sorption was determined under static conditions depending on the pH of the solution. The sorption isotherms and retention were investigated under dynamic conditions.     

Some investigations on the photostabilization of polypropylene

The effect of substituted hydroxybenzophenone, benzotriazole and organic metal complexes on the photooxidation of PP films has been studied. It has been established that NiDBTC added in 1.0 wt. % is the most effective photostabilizer.While in the case of other stabilizers there is a slight increase in the Co content even during the induction period, with the application of NiDBTC practically no oxidation can be observed before the stabilizer completely disappears. This means that NiDBTC inhibits the photooxidation of the polymer even in low concentration.

---

, - . , Ni, 1,0 . %. . , Ni , . , Ni .

     

Thermal decomposition of copolymers of styrene and halogenated monomers

Copolymers of 1,2,2,2-tetrachloroethyl esters of unsaturated acids and halogenated N-phenyl maleimides with styrene were pyrolyzed; volatile products were analyzed with a mass spectrometer combined with a gas chromatograph. Hydrogen halide and carbon dioxide in the volatile products were determined during the thermal decomposition of copolymers in glass ampoules; the acyl chloride groups were determined in the residues. The thermal decomposition of copolymers of tetrachloroethyl esters with styrene sets in at ca. 230° by the release of chloral from the copolymer and splitting of some of the CCl bonds in the copolymer. The decomposition of copolymers of styrene with halogenated N-phenyl maleimides starts above 300° by depolymerization of the polystyrene chain sections and by splitting of some of the carbon-halogen bonds. At 310 and 500° for copolymers of tetrachloroethyl esters and at 500° for halogenated N-phenyl maleimides, there is radical dehydrohalogenation of the copolymers, with depolymerization of polystyrene blocks and splitting of carbon-carbon bonds in the main chain.     

A field theoretical approach to calculate electronic Born-Oppenheimer coupling terms

In this paper we suggest to consider the spatial distribution of the Born-Oppenheimer nonadiabatic coupling terms as fields which are created by sources, located at degeneracy points, and which can be derived using the ordinary mathematical tools of field theory. It is shown that the curl-divergence equations as formed within a given Hilbert space [M. Baer, Chem. Phys. Lett. 35, 112 (1975)] can be converted into a set of inhomogeneous coupled Poisson equations which are solved for a given set of boundary conditions. The method is applied to the three-state Hilbert subspace of the H(3) system. The numerical results are compared with ab initio calculations for which a very encouraging fit is found.     

Hydration of acetylene on Cd2+ exchanged zeolites

The reaction takes place on Cd-containing Lewis sites, whereas the irreversible adsorption and condensation of product acetaldehyde on acidic OH groups of Cd-X, FAU catalyst results in deactivation. Preadsorbed ammonia moderates the deactivation, because it reacts with acetylene, and pyridine homologues are formed which block the accessible OH groups. Since in divalent cationic forms of clinoptilolite no OH groups are generated, Cd-clinoptilolite proved to be a catalyst of permanent activity.

---

, Cd, — OH FAU, Cd-X. , .. , OH . OH, Cd- .

     

Properties and analytical applications of the heteropolymolybdates of phosphorus, arsenic, silicon and germanium-IV Determination of phosphomolybdic and silicomolybdic acids via the molybdenum content, with phenylfluorone

Procedures are proposed for the determination of phosphorus and silicon in the ppM range, by extraction of phosphomolybdic and silicomolybdic acids with organic solvent, decomposition of the complex and spectrophotometric determination of its molybdenum content.     

Complex study of nickel skeleton catalysts: V. Study of novel non-pyrophoric nickel skeleton catalysts by derivatograph

The structure and properties of non-pyrophoric skeleton catalysts prepared from NiSi, NiAlSi, NiMg and NiZn alloys have been studied—apart from other thermal methods—by means of the derivatograph.Our experimental results have contributed to the explanation of the non-pyrophoric behaviour of these catalysts. We demonstrated that the desorption of the hydrogen content in our catalysts is not accompanied by the oxidation of active nickel. This oxidation takes place only at higher temperatures, above 200°C, at a rate proportional to the amount of active nickel.Other constituents of the catalysts (adsorbed water, hydroxide content) were also determined from the experimental data. The outstandingly high Mg(OH)₂ content of the NiMg catalyst indicates that its structure is dissimilar: Mg(OH)₂ also acts as support for the catalyst.