WP15 ConCorD state-of-the-art report (container corrosion under disposal conditions)

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Microbiologically influenced corrosion (MIC) is the process of material degradation in the presence of microorganisms and their biofilms. This is an environmentally assisted type of corrosion, which is highly complex and challenging to fully understand. Different metallic materials, such as steel alloys, magnesium alloys, aluminium alloys, and titanium alloys, have been reported to have adverse effects of MIC on their applications. Though many researchers have reported bacteria as the primary culprit of microbial corrosion, several other microorganisms, including fungi, algae, archaea, and lichen, have been found to cause MIC on metal and non-metal surfaces. However, less attention is given to the MIC caused by fungi, algae, archaea, and lichens. In this review paper, the effects of different microorganisms, including bacteria, fungi, algae, archaea, and lichens, on the corrosion properties of engineering materials have been discussed in detail. This review aims to summarize all of the corrosive microorganisms that directly or indirectly cause the degradation of structural materials. Accusing bacteria of every MIC case without a proper investigation of the corrosion site and an in-depth study of the biofilm and secreted metabolites can create problems in understanding the real cause of the materials’ failure. To identify the real corrosion agent in any environment, it is highly important to study all kinds of microorganisms that exist in that specific environment.

Transverse approach between real world concentrations of SO2, NO2, BTEX, aldehyde emissions and corrosion in the Grand Mare tunnel

This paper considers the process of fatigue failure of metal specimens subjected to cyclic low-amplitude dynamic loading. The presence of holes in them forms zones of increased stresses, in which the process of material degradation is initiated. To describe this physical effect, a multi-mode continuum model of fatigue failure fracturing is used. It is based on supplementing the defining system of equations of an isotropic linear elastic body with an evolutionary equation for the damage function in the number of loading cycles. The case of normal tensile microcrack formation specified by the Smith–Watson–Topper criterion is considered. Due to the different scales of these processes, the computer calculation is organized as a two-stage computational algorithm. Each loading act is calculated in a full dynamic formulation, which is due to the high frequency of application of external stresses. For the numerical solution of the deformation problem, the grid-characteristic method on structured computational grids is used. The method of overlapping grids is used to describe the geometry of the hole, which allows for the efficient use of the computing system resources. A series of calculations was performed, demonstrating the high-quality reproduction of the patterns of macrocrack propagation.

This article is dedicated to the problems and processes of the activation of scientific and technological progress in the context of contemporary challenges of the creation of a knowledge-based society and knowledge economy. The main focus here is on activating innovations, scientific and technological progress and creating various preconditions for the development of a knowledge-based society and knowledge economy.The contemporary processes and phenomena of innovations of scientific and technological progress and of its activation are analyzed in a complex manner; the needs for the purposeful activation and acceleration of scientific and technological progress, in particular in response to the aspirations of the knowledge-based society and the creation of a knowledge economy, are investigated in the presented material.The role and importance of innovation activities and the acceleration of scientific and technological advance in the context of the creation of a knowledge-based society and a knowledge economy are revealed and highlighted. New ideas of the search and use of synergetic effects, as well as a new theoretical approach based on the so-called universal principle of the creation of a “new quality,” are described.The results of the presented research can be used for preparing practical recommendations and methodologies that could be applied in the creation and implementation of the managerial and economic instruments and support systems aimed at the purpose of activating the processes of innovations and scientific and technological progress. These recommendations and methodolies could also be utilized in the development of international relations in the context of what is required in the creation of a knowledge-based society and knowledge economy.It is shown that the problems and processes of scientific and technological progress can be appreciated as an extremely important and viable field of scientific research on the creation and development of a knowledge economy.
 Keywords: knowledge economy, scientific and technological progress, innovation, synergy, networking

Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

Draw hook failures present significant problems for railway safety and operational efficiency. Although failures on the draw gear are not frequent, they can induce serious problems on the vehicles and infrastructure when some elements break. This paper presents comprehensive research on the potential causes of these failures, aiming to provide insights for prevention measures related to materials, production process, geometry and manipulation practices during train operation. The draw hook, as one of the vital components in connections of wagons and locomotives, ensures the safety and reliability of trains during operation. By analyzing the historical failure data and relevant literature, this study identifies several key factors contributing to coupler failures. Material degradation emerges as a prominent concern, with factors such as fatigue, wear, and corrosion compromising the structural integrity of the coupler hook and other components over time. Overloading during starting, impacts, or improper coupling procedures further increase the risk of failures. Mechanical and physical characteristics of used material, as well as geometric inconsistencies, may also induce failure under operational conditions. Environmental factors, such as extreme temperatures, moisture ingress, and chemical exposure, pose additional challenges by accelerating material degradation and corrosion processes. Understanding the complex interaction of these factors is crucial for developing effective preventive maintenance strategies and for addressing and improving observed imperfections in draw gear elements. Implementing the results from this research can help railway operators and manufacturers of subjected elements mitigate the risk of failures, thereby ensuring the continued reliability and safety of rail transportation systems.

Degradation and volatilization process of fragrance materials and triclosan in wastewater treatment plant – Comparison between field survey and laboratory experiment –

Our purpose is to analyse the speed and contribution of the educational scientific and technological progress in the development of the primary forestry industry. In order to research the role of the educational scientific and technological progress in the development of the primary forestry industry more scientifically, the article employs the modified multi-factor two-level CES production function model, and the data from 31 provinces over 19 years (1994-2012), to measure and calculate the speed and contribution of the educational scientific and technological progress in the development of the primary forestry industry from the two dimensions, time and space. The speed of educational scientific and technological progress in the primary forestry industry was 2.8% from 1994 to 2012, and the contribution rate of educational scientific and technological progress to the development of the primary forestry industry was 49.6%. Through the measuring and calculating of different periods, it is found that there were big differences between different periods regarding to the contribution of the educational scientific and technological progress to the development of the primary forestry industry, and the contribution grew quickly in the last few years. Through the measuring and calculating of different areas, it is found that there were huge differences between different areas regarding to the contribution of the educational scientific and technological progress to the development of the primary forestry industry, due to the difference in nature, society and economic environment. Along with the development of the economy, the structure of the forestry industry needs important changes. The dominating status of the primary forestry industry in the forestry industry should be strengthened. The educational science and technology investment of the primary forestry industry should be boosted, to lead the development of the primary forestry industry onto a path relying on the progress of educational science and technology. In the process of making the development policy and investment policy on the primary forestry industry, it shall not impose uniformity in all cases. On the contrary, the policy shall vary according to the different situations; and it is noticed that the comparative advantages of different areas with different social economic and natural resources shall be exerted.

This paper reviews the findings of research reported in the currently available literature regarding the occurrence and transformations of pesticides through the composting process and the use of compost. Part I summarizes the composting process, pesticides and mechanisms of pesticide degradation. Part II reviews research studies concerning the occurrence and fate of pesticides during composting. Investigations of pesticide residues in composting feedstocks and finished compost detected few of the target pesticides. The compounds that were found occurred at low concentrations. The majority of the compounds detected were insecticides in the organochlorine category, including chemicals that have been banned from use in the U.S. for many years. Generally, organophosphate and carbamate insecticides and most herbicides were rarely detected. Comparisons of pesticide concentrations before and after composting also showed organochlorine compounds to be most resistant to biodegradation during composting. With some exceptions, pesticides in other categories decomposed moderately well to very well. Studies that followed the mechanisms of degradation indicate that mineralization accounts for only a small portion of pesticide disappearance. Other prominent fates include partial degradation to secondary compounds, adsorption, humification, and volatilization. In general the research results suggest that the pattern of pesticide degradation during composting is similar to the degradatiion observed in soils. With a few important distinctions, composting can be considered a biologically active soil environment in which degradation is accelerated. However, as some studies noted, composting does not always speed the degradation of all pesticides. The nature of the pesticide, specific composting conditions and procedures, the microbial communities present, and the duration of composting affect the extent and the mechanisms of degradation.

6 - Degradation Processes and Mechanisms of Encapsulants

The degradation of bio-based plastic materials in field soil under natural conditions was investigated in this study. Three bio-based plastics materials, which contained polylactide (PLA) with polybutylene adipate terephthalate and additives (PLA_1), PLA-based polyester blend with mineral filler (PLA_2), and polybutylene succinate with mineral filler (PBS_1) in the form of the film, were subjected to soil burial biodegradation processes. The experiments were carried out in a climate with an average annual temperature of 9.4 °C, in winter and summer periods for one year. The degradation of the materials was evaluated by macro- and microscopic observations, weight loss, thermogravimetric analysis, and tensile test. Macroscopic observation indicated that changes in the color of film surface were visible for samples PBS_1 after 12 months of degradation. Using microscopic inspection the erosion of surface samples PLA_1 and PBS_1 after 12 months was observed. Mass loss of samples PLA_1 and PLA_2 after one year of degradation were below 0.6 %. Moreover, for PBS_1 sample, mass loss was equal to 4.3 %. Based on the obtained results of the mass loss, a description of the degradation kinetics was proposed, showing the changes in the thickness of the tested polymer over time. The thermal stability of the samples PLA_1 and PLA_2 decreased during the degradation process by 16.1 and 2.6 °C, respectively, and for PBS_1 increased by 1.7 °C. Tensile strength at break after 12 months of degradation decreased for sample PLA_1 and PLA_2 by 27.3 and 5.8 %, respectively, and increased for sample PBS_1 by 28.2 % compare to unexposed sample.

It is an effective and feasible way to dispose cemented waste form from nuclear power plant in the rock cavern disposal site. Simulation work with Ecolego software was conducted in this paper to better quantify the transfer process of nuclides in cemented waste form in the rock cavern disposal site over a long time scale. A rock cavern disposal site of low and intermediate radioactive waste was taken as an example. For the transfer process of the nuclides crossing the metal steel drums to the concrete disposal container, 3 sets of compartment models were established respectively. One was for the convective transfer process, and the other two were for the diffusion process in the not deteriorated or partially deteriorated cemented waste form. Release activities of Co-60, Sr-90, Cs-137, Ni-63 and I-129 were calculated with a period of 1000 years beginning at the closing point of the disposal site. In the case of convective transfer, the total peak release time occurs in 120 years after the closure of the disposal site, and the dominant nuclide is Cs-137. During the 1000 years, almost all of the I-129 is released into the concrete disposal container. In the case of diffusion transfer, the total peak release rate occurs in 103 years after the closure of the disposal site, and the dominant nuclide is still Cs-137. During the 1000 years, the total release ratio of I-129 head the list. The total release ratio of Co-60 is almost zero in both processes. Results show that Cs-137 wins top places in the peak release rate and total release activity in both convective and diffusion transfer cases, indicating that Cs-137 is the most concerned nuclide in the release of cemented waste form. The peak release rate and total release activity of each nuclide under diffusion process were lower than those under convective transfer process, regardless of whether the cemented waste form was degraded or not, indicating that the release of transfer under convection transfer was more significant. The total release activity of all nuclides in the diffusion process of the partially deteriorated cemented waste form is 161.434% higher than that of the non-degraded cemented waste form, which shows that the deterioration of the cemented waste form has a significant impact on the diffusion process. This paper is the very first domestic evaluation study on the transfer process of nuclides in the cemented waste form and the metal barrel under the condition of rock cavern disposal. The results can provide an effective basis for the safety assessment and the engineering scheme design of the disposal site.

Proton exchange membrane hydrogen fuel cell (PEMFC) deployment is presently limited by the high material cost of oxygen reduction reaction (ORR) electrocatalysts at the cathode. Developing low-cost, earth-abundant alternatives for use in acidic environments presents a material stability challenge, especially for long-term device operation. Platinum (Pt)-based materials are used in typical commercial PEMFC cathode formulations due to their simultaneous high performance and long-term stability despite the prohibitively high material cost. Developing lower-cost, longer-life catalyst materials based on earth abundant transition metals can accelerate the adoption of PEMFC technology. The impact of potential, current density, and local microenvironment has been shown to cause degradation of non-Pt materials but standard ex situ measurements can only probe surface restructuring and cumulative dissolution after operation. Material-specific degradation mechanisms that are strong functions of the operating conditions cannot be ascertained without in situ quantification of material degradation under PEMFC-relevant conditions. Information about the degradation pathways of these non-precious catalysts can assist with material design for devices; however, most efforts towards developing an in-situ understanding of PEMFC cathode catalyst degradation under operating conditions are generally limited to Pt-based materials. Extensive in situ characterization has revealed Pt-specific mechanistic information about corrosion pathways as well as conditions that exacerbate Pt alloy leaching. It has been hypothesized that the Pt degradation processes are related to oxide formation under potential cycling. With this critical in-situ information, Pt conditioning protocols have been developed to enhance material lifetime; however, investigations on non-precious materials are less common. Insights into non-precious catalyst degradation in PEMFC operating conditions are not as well-established but could be essential in enabling low-cost materials for commercial use. There is a need for more insights into a vast array of materials which necessitates the development of faster, preferably benchtop techniques for degradation analysis.In this work, we use an in situ electrochemical flow cell assembly and coupled it with an inductively coupled plasma-mass spectrometer (ICP-MS) to quantify the loss of material in real time for several non-Pt materials under reaction conditions. The flow cell is fed by a peristaltic pump at 2.5 mL/min of gas-saturated acidic electrolyte for optimal mass transport. The cell has a three-electrode configuration with a compression-mounted metal foil working electrode, silver/silver chloride reference electrode, and Pt counter electrode downstream of other components. We evaluate a variety of transition metals across the spectrum of ORR activity: palladium, silver, nickel, copper, manganese, and cobalt. Each metal is tested under oxygen and nitrogen saturation in five electrolytes of identical pH: perchloric acid, sulfuric acid, nitric acid, hydrochloric acid, and hydrobromic acid. This setup allows for nearly real time measurement of ORR kinetics and in situ element-specific dissolution rates as a function of time. With careful design of experimental conditions and controlled variables, we are able to suggest mechanisms of degradation with specific reference to conditions under which material loss occurred such as high/low potential, oxygen-saturated/nitrogen-saturated electrolyte, or faradaic/non-faradaic current. We find some metals are stable under nitrogen-saturated electrolyte but corrode more under oxygen-saturated electrolyte only while ORR active. Furthermore, other metals are stable in nitrogen saturated electrolyte at all tested electrochemical conditions but unstable under oxygen saturated electrolyte but only outside the ORR range, implying that cathodic faradaic processes might be stabilizing the surface at low potentials. This stabilization where a thermodynamically unstable material (based on its Pourbaix diagram) exhibits greater immunity while performing ORR in certain electrolytes could inform the development stability mechanisms that direct the design of next generation, non-precious PEMFC cathode catalyst materials. With combined in situ catalyst stability analysis in five pH 1 electrolytes, we can recommend specific conditions for optimizing activity and stability based on the potential range of operation and the electrolyte composition/saturation. We can also distill mechanistic insights from these experiments by creating models that validate causes of catalyst degradation. These models are built using “graphical causal modeling”, which is a mathematical field that goes beyond correlative predictions by venturing into causal inference. We hope to expand this framework into other electrocatalytic reactions of interest. The in-situ ICP-MS electrochemical flow cell setup exhibits promise for accelerating materials stability analysis for enabling next generation Pt-free ORR electrocatalysts through practical experiments and direct comparability to established electrochemical techniques.

The study of insulation degradation processes is crucial for the reliable operation of power equipment and electronic devices. The phase field method has been widely used in recent years to simulate the degradation process of insulation materials. However, the effect of space charge was ignored. In this paper, a novel phase field method based on the bipolar carrier transfer model is suggested. This model can simulate degradation under different temperatures and DC or combined AC/DC voltage. The cases under AC and combined AC/DC voltage at different temperatures are simulated by COMSOL. Methods to ensure model convergence are proposed. The results show that the field strength distribution under a combined AC/DC field is more uniform, especially for negative polarity. For the same voltage form, temperature and breakdown time show an exponential relationship. The results are consistent with those of previous experimental studies, proving the usability of the model. In addition, the processes of initiation, growth, and breakdown stage of the dielectric degradation process, as well as the stagnation period, are explored theoretically. The stagnation time at low temperatures under combined AC/negative DC voltage is long. The research in this paper is useful for insulation optimization design, condition assessment, and longevity prediction.