NON-ISOTHERMAL KINETICS OF SOLID-PHASE DECOMPOSITION OF MIXTURES OF OCTOGEN WITH NITRO-NITROZOAMINES

Определены формально-кинетические характеристики термораспада нитро-нитрозоаминов и их смесей с октогеном. Реакция разложения нитрозоаналогов октогена и нитро-нитрозопроизводных тетраазадекалина характеризуется меньшей энергией активации по сравнению с октогеном, и протекает с большей скоростью. Проведен анализ активационных параметров термораспада смесей, установлено активирующее влияние нитрозопроизводных тетраазадекалина на разложение октогена. The formal-kinetic characteristics of the thermal decomposition of nitro-nitrosoamines and their mixtures with HMX have been determined. The decomposition reaction of nitroso analogs of HMX and nitro-nitroso derivatives of tetraazadecalin is characterized by a lower activation energy compared to HMX, and proceeds at a higher rate. The analysis of the activation parameters of the thermal decomposition of the mixtures was carried out, the activating effect of the nitroso derivatives of tetraazadecalin on the decomposition of HMX was established.

The effect of the temperature dependence of the heat conductivity on the physical laws of the bulk synthesis of a composite

Two-dimensional model of high-temperature synthesis of chemical compounds and alloys in a dynamic thermal explosion mode when a powder compact is heated in a steel cylindrical mold by an induction heat source are proposed. The complex of chemical reactions is described by a total reaction with effective formal kinetic parameters. The kinetic law takes into account strong retardation of the reaction by the layer of the synthesized product that prevents the interaction of the reagents. The model makes it possible to investigate the macroscopic physical laws of the synthesis of a composite with a change in the heating rate and reactor dimensions. It is made a comparison of the results obtained for a constant heat conductivity coefficient and a temperature-dependent heat conductivity coefficient. It is revealed that taking into account the temperature dependence of the heat conductivity coefficient can lead to a numerical change in the ignition delay time and to a qualitatively different temperature distribution in the reactor bulk.

MODELING OF PYROLYSIS OF OIL RESIDUES IN THE PRESENCE OF ALUMINOSILICATES

Данная работа посвящена изучению кинетики процесса каталитического пиролиза кубовых остатков нефти. Исследование проводилось методом термогравиметрии с различной скоростью нагрева образца (2,5; 5 и 10 К/мин). В качестве катализаторы была использована синтезированная каталитическая система: ZSM-5/бентонитовая глина с импрегнированным металлом (Со - 2 % масс.). При моделировании были определены формальные кинетические параметры Аррениуса процесса деструкции. Рассчитанная модель представляет собой двухстадийный параллельный процесс. Значения энергий активации деструкции для первой стадии составило 58 кДж/моль и 188 кДж/моль для второй. This work is devoted to the study of the kinetics of the process of catalytic pyrolysis of oil residues. The study was performed by thermogravimetry with different sample heating rates (2.5, 5, and 10 K / min). A synthesized catalytic system was used as a catalyst: ZSM-5 / bentonite clay with impregnated metal (Co-2% wt.). Formal kinetic parameters of the Arrhenius of the destruction process were determined During modeling. The calculated model is a two-stage parallel process. The destruction activation energies for the first stage were 58 kJ/mol and 188 kJ/mol for the second stage.

TO004IMPACT OF RENAL TRANSPLANT ON COGNITIVE FUNCTION AMONG ESRD PATIENTS ON DIALYSIS

Background and Aims Kidney transplantation can help in mitigating neuropsychological (NP) impairments in end-stage renal disease (ESRD). Evidences have shown mixed responses on the the nature of cognitive function in patients who have undergone renal transplantation.Present study looked into the factors impacting cognitive domains and impact post transplant. Method 43 patients who were stable ESRD on thrice a week hemodialysis were investigated 6 months pre and post transplant using a battery of neurophysiological testing assessing attention–concentration, psychomotor ability and memory. Formal kinetic modelling of dialysis delivery ensured adequate renal replacement therapy. Transplant function was assessed on regular interval and following a stable graft function and on stable doses of immunosuppressive medication 6 months post transplant were reassessed Results Within-subject comparisons showed statistically significant improvement in memory performance after kidney transplant. Other NP measures (attention– concentration and psychomotor abilities) showed non-significant improvements. Normative comparisons showed NP impairments on dialysis, which were not apparent after transplant Conclusion These data demonstrate improvements in cognition following kidney TX and emphasize the reversibility of the memory problems evidenced in dialysis

Kinetics of extraction from water solutions of Fe3+, Cu2+ and Pb2+ + ions by filter loading, obtained by blinding plasters

In this study, we investigated the kinetics of extraction from aqueous solutions of Fe3+, Cu2+ and Pb2+ by filter loadings, derived from the steelmaking slags. A formal kinetic approach based on the relationship between the relative deposition rate (α) and time (τ) was used to estimate the mechanism and kinetic parameters of the deposition process). From the set of equations are selected those that in a given region of the degree of completion of the process gave the minimum value of the variance, that is, described the process in the system at this stage with the maximum probability. Three models that best correspond to real processes are selected. It was found that the deposition process at the initial stage limits the chemical stage of nucleation (formation of crystalline precipitate), then – the reaction at the interface (formation of a continuous layer of reaction products on the surface of the nuclei), and at the final stage – the growth of a continuous layer of reaction products.

Research of Formal-Kinetic Regularities of the Curing Process of Low-Viscosity Epoxy Binder

The expanding range of components intended for manufacturing products of polymer composite materials is often not accompanied by comprehensive information on the characteristics and recommended technological curing modes. The relevance and practical significance of this investigation are based on the need to predict rational technological modes for curing products of polymer composite materials based on the low-viscosity epoxy binder Etal-Inject-SLM, which is in demand in the manufacture of products from polymer composite materials by cold curing. The purpose of this investigation is to determine kinetic patterns, which allow for predicting the time and degree of curing of the low-viscosity epoxy binder Etal-Inject-SLM for various isothermal curing conditions. The method of differential scanning calorimetry was used to measure the thermal effect of the curing reaction of the Etal-Inject-SLM epoxy binder at various heating rates. Based on the experimental calorimetric data and using the model-free (non-prior) Friedman method, using the specialized software Netzsch Kinetics Neo, the parameters characterizing the formal kinetic laws of the curing process were calculated. This allowed for plotting isothermal and iso-conversion thermokinetic diagrams necessary for predicting the time and degree of curing of the Etal-Inject-SLM binder at different temperatures and curing times. This results can be useful for optimizing technological processes in which the low-viscosity epoxy binder Etal-Inject-SLM is used.

Critical Appraisal of Kinetic Calculation Methods Applied to Overlapping Multistep Reactions

Thermal decomposition of solids often includes simultaneous occurrence of the overlapping processes with unequal contributions in a specific physical quantity variation during the overall reaction (e.g., the opposite effects of decomposition and evaporation on the caloric signal). Kinetic analysis for such reactions is not a straightforward, while the applicability of common kinetic calculation methods to the particular complex processes has to be justified. This study focused on the critical analysis of the available kinetic calculation methods applied to the mathematically simulated thermogravimetry (TG) and differential scanning calorimetry (DSC) data. Comparing the calculated kinetic parameters with true kinetic parameters (used to simulate the thermoanalytical curves), some caveats in the application of the Kissinger, isoconversional Friedman, Vyazovkin and Flynn–Wall–Ozawa methods, mathematical and kinetic deconvolution approaches and formal kinetic description were highlighted. The model-fitting approach using simultaneously TG and DSC data was found to be the most useful for the complex processes assumed in the study.