Quantitative Assessment of the Kinetics of Damage Accumulation in the Polymer Matrix Structure Under Full-Scale Climatic Factors and Tensile Loads

Постановка задачи. Изучено изменение упруго-прочностных показателей и кинетики накопления повреждений в эпоксидных полимерах под действием растягивающих нагрузок в контрольном состоянии и после натурного климатического воздействия в течение одного календарного года. Расчет кинетики накопления повреждений осуществлялся на основе авторской методики, основанной на использовании методов фрактального анализа кривых деформирования образцов полимерных материалов при растяжении. Результаты. Предложен удельный показатель θ, позволяющий количественно оценивать суммарное число повреждений на единицу прочности, накопление которого приводит к разрушению полимеров. Получены аппроксимирующие зависимости, описывающие взаимосвязь между удельным показателем θ и пределом прочности эпоксидных полимеров при растяжении. Выводы. Установлено, что наибольшей стабильностью свойств под действием натурного климатического воздействия обладает полимер на основе эпоксидной смолы «Этал-247». Statement of the problem. In the current study we look at the change in the elastic-strength performance and kinetics of damage accumulation in epoxy polymers under tensile loads in the control state and after full-scale climatic exposure during one calendar year were studied. Damage accumulation kinetics was calculated based on the author's method using methods of fractal analysis of deformation curves for polymer materials samples under tension. Results. We proposed specific index θ to quantify the total number of damages per unit of strength where its accumulation leads to the destruction of polymers. The dependences have been obtained that describe the relationship between specific index θ and tensile strength of epoxy polymers. Consclusion. The study has shown that the Etal-247 epoxy resin-based polymer cured with Etal-1440 amine hardener has the most stable properties under the full-scale climatic exposure.

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QUANTITATIVE ASSESSMENT OF THE KINETICS OF DAMAGE ACCUMULATION IN THE POLYMER MATRIX STRUCTURE UNDER FULL-SCALE CLIMATIC FACTORS AND TENSILE LOADS

Russian Journal of Building Construction and Architecture ◽

10.36622/vstu.2021.52.4.006 ◽

2021 ◽

pp. 63-71

Author(s):

V. P. Selyaev ◽

D. R. Nizin ◽

N. S. Kanaeva

Keyword(s):

Damage Accumulation ◽

Climatic Factors ◽

Full Scale ◽

Polymer Materials ◽

Strength Performance ◽

Deformation Curves ◽

Specific Index ◽

Accumulation Kinetics ◽

The Relationship ◽

Kinetics Of

Statement of the problem. In the current study we look at the change in the elastic-strength performance and kinetics of damage accumulation in epoxy polymers under tensile loads in the control state and after full-scale climatic exposure during one calendar year were studied. Damage accumulation kinetics was calculated based on the author's method using methods of fractal analysis of deformation curves for polymer materials samples under tension.Results. We proposed specific index θ to quantify the total number of damages per unit of strength,where its accumulation leads to the destruction of polymers. We obtained approximating dependences that describe the relationship between specific index θ and tensile strength of epoxy polymers.Consclusion. The study has shown that the Etal-247 epoxy resin-based polymer cured withEtal-1440 amine hardener has the most stable properties under the full-scale climatic exposure.

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Method for analyzing the kinetics of damage accumulation in the structure of polymer materials under tensile stresses

10.1063/5.0059899 ◽

2021 ◽

Author(s):

Tatyana Nizina ◽

Dmitriy Nizin ◽

Nadezhda Kanaeva ◽

Denis Artamonov

Keyword(s):

Damage Accumulation ◽

Polymer Materials ◽

Tensile Stresses ◽

Kinetics Of

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The Effect of Natural Climatic Aging on Damage Accumulation Kinetics in the Structure of Epoxy Polymers Under Tensile Loads

Lecture Notes in Civil Engineering - Proceedings of the International Conference Industrial and Civil Construction 2021 ◽

10.1007/978-3-030-68984-1_22 ◽

2021 ◽

pp. 147-153

Author(s):

D. R. Nizin ◽

T. A. Nizina ◽

N. S. Kanaeva ◽

A. I. Gorenkova

Keyword(s):

Damage Accumulation ◽

Epoxy Polymers ◽

Accumulation Kinetics

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Tbx21 and Foxp3 Are Epigenetically Stabilized in T-Bet+ Tregs That Transiently Accumulate in Influenza A Virus-Infected Lungs

International Journal of Molecular Sciences ◽

10.3390/ijms22147522 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7522

Author(s):

Yassin Elfaki ◽

Juhao Yang ◽

Julia Boehme ◽

Kristin Schultz ◽

Dunja Bruder ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Influenza A Virus ◽

Influenza A ◽

T Cell Subsets ◽

T Helper 1 ◽

T Box ◽

Cell Responses ◽

Accumulation Kinetics ◽

Kinetics Of

During influenza A virus (IAV) infections, CD4+ T cell responses within infected lungs mainly involve T helper 1 (Th1) and regulatory T cells (Tregs). Th1-mediated responses favor the co-expression of T-box transcription factor 21 (T-bet) in Foxp3+ Tregs, enabling the efficient Treg control of Th1 responses in infected tissues. So far, the exact accumulation kinetics of T cell subsets in the lungs and lung-draining lymph nodes (dLN) of IAV-infected mice is incompletely understood, and the epigenetic signature of Tregs accumulating in infected lungs has not been investigated. Here, we report that the total T cell and the two-step Treg accumulation in IAV-infected lungs is transient, whereas the change in the ratio of CD4+ to CD8+ T cells is more durable. Within lungs, the frequency of Tregs co-expressing T-bet is steadily, yet transiently, increasing with a peak at Day 7 post-infection. Interestingly, T-bet+ Tregs accumulating in IAV-infected lungs displayed a strongly demethylated Tbx21 locus, similarly as in T-bet+ conventional T cells, and a fully demethylated Treg-specific demethylated region (TSDR) within the Foxp3 locus. In summary, our data suggest that T-bet+ but not T-bet− Tregs are epigenetically stabilized during IAV-induced infection in the lung.

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Phosphorus removal by apatite in horizontal flow constructed wetlands for small communities: pilot and full-scale evidence

Water Science & Technology ◽

10.2166/wst.2011.250 ◽

2011 ◽

Vol 63 (8) ◽

pp. 1629-1637 ◽

Cited By ~ 8

Author(s):

N. Harouiya ◽

S. Martin Rue ◽

S. Prost-Boucle ◽

A. Liénar ◽

D. Esser ◽

...

Keyword(s):

Constructed Wetlands ◽

Particle Surface ◽

Full Scale ◽

Retention Capacity ◽

Small Communities ◽

Lab Experiments ◽

Apatite Mineral ◽

Kinetics Of ◽

P Removal

Phosphorus (P) removals in constructed wetlands (CWs) have received particular attention in recent decades by using specific materials which promote adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilot units and a full-scale plant over a 2 year period. P retention kinetics of two qualities of apatites are presented and discussed. In this work apatite appears to have high retention capacity (>80% of P removal) and is still an interesting way for P removal in CWs for limiting the risk of eutrophication downstream of small communities. Nevertheless, the apatite quality appears to be of great importance for a reliable and long term P removal. The use of materials with low content of apatite mineral (40–50%) seems to be not economically relevant.

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Kinetics of mercury accumulation by freshwater biofilms

Environmental Chemistry ◽

10.1071/en17073 ◽

2017 ◽

Vol 14 (7) ◽

pp. 458 ◽

Cited By ~ 3

Author(s):

Perrine Dranguet ◽

Vera I. Slaveykova ◽

Séverine Le Faucheur

Keyword(s):

Food Webs ◽

Food Chain ◽

Microbial Composition ◽

Biofilm Thickness ◽

Aquatic Microorganisms ◽

Uptake Rate Constant ◽

The Difference ◽

Accumulation Kinetics ◽

Kinetics Of ◽

Hg Accumulation

Environmental contextMercury (Hg) is a major environmental contaminant due to its toxicity, accumulation and biomagnification along the food chain. We demonstrate that Hg accumulation by biofilms, one possible entry point for Hg into food webs, is rapid and depends on biofilm structure and composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms. AbstractMercury contamination is of high concern due to its bioaccumulation, toxicity and biomagnification along the food chain. Biofilms can accumulate Hg and contribute to its incorporation in freshwater food webs. Nevertheless, the accumulation kinetics of Hg by biofilms is not well described and understood. The aim of the present study was thus to gain mechanistic understanding of Hg accumulation by biofilms. Kinetics of Hg uptake by biofilms of different ages (e.g. different compositions) was characterised by determining Hg contents in biofilms with and without a cysteine-washing step. Hg accumulation was rapid in both biofilms, with the uptake rate constant of the younger biofilm 10 times higher than that of the older biofilm. Moreover, accumulated Hg reached a plateau at 24h exposure in the younger biofilm, whereas it increased linearly in the older biofilm. The observed difference in Hg uptake by the studied biofilms is likely a result of the difference in biofilm thickness (and thus Hg diffusion inside the biofilm matrix) and microbial composition. These findings have important implications for the understanding of Hg bioavailability and effects towards aquatic microorganisms.

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Principles of exposure of polymer materials to heat, moisture and UV-radiation and study of their properties by full factorial experiment: A review

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2021-106-2-146-160 ◽

2021 ◽

pp. 146-160

Author(s):

A. B. Laptev ◽

A. S. Nesterov ◽

A. M. Vardanyan ◽

A. M. Vardanyan

Keyword(s):

Uv Radiation ◽

Climatic Factors ◽

Initial Period ◽

Amorphous State ◽

Surface Oxidation ◽

Polymer Chains ◽

Factorial Experiment ◽

Polymer Materials ◽

Full Factorial Experiment ◽

Full Factorial

The work is dedicated to the effects of climatic factors on polyethylene terephthalate (PET) in terms of changes in the structure and interaction of polymer molecules. The kinetic concept of the strength of PET has been developed, and the factors influencing the strength have been considered. Effects of moisture, thermal oxidative destruction, and UV-radiation on the structure of PET have been investigated. Polymers’ properties predicting, durability and their computer modeling have been analyzed. A model of changes in PET properties under the influence of temperature, moisture and UV-radiation was constructed using the methods of a full factorial experiment. It has been shown that in the initial period of exposure, adsorption and diffusion of moisture, hydrolysis and surface oxidation occur; prolonged and constant exposure to UV-radiation break the bonds formed by moisture, then the C–C and C–O bonds in the PET molecule brake and new intermolecular bonds are formed. In the amorphous state of PET, the breaking of bonds in the polymer chain and the formation of bonds between two adjacent polymer chains, the formation of more densely packed nodes, the destruction of the polymer and its aging, are equally probable. Temperature has a secondary effect, facilitating both hydrolysis and oxidation and polymer degradation.

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