bluuebunny/crossref_metadata_2025 huggingface dataset:
इरफान अली कथाको सबाल्टर्न विश्लेषण
Authors: नेपाल टीकाराम
Published: October 2024

प्रस्तुत लेखमा नारायण ढकालको ‘इरफान अली’ कथालाई सबाल्टर्न अध्ययनका दृष्टिले विश्लेषण गरिएको छ । सबाल्टर्न शब्दले सामान्यतः वर्ग, लिङ्ग, जाति, उमेर, भाषा, कार्यगत दर्जालगायत हरेक हिसाबले विभेद गरिएका, शोषण र उत्पीडनको सिकार भएका व्यक्ति वा समुदायलाई जनाउने गर्दछ । प्रस्तुत कथाको मुख्य पात्र इरफान अली मूलत M जातीय, भाषिक र आर्थिक रूपले सबाल्टर्न बन्न पुगेको तथ्यलाई यस आलेखमा विभिन्न साक्ष्यमार्फत प्रस्तुत गरिएको छ । जातीय, भाषिक, वर्गीय जस्ता आधारबाट सबाल्टर्न बन्नुपरेको स्थितिलाई देखाउँदै राज्यसत्ताको चरम दमन र शोषणविरुद्ध सबाल्टर्नवर्ग एकजुट हुनुपर्छ भन्ने विचार कथामा आएको छ । जातीय, भाषिक तथा आर्थिक दृष्टिबाट ‘इरफान अली’ कथा कसरी सबाल्र्टनमैत्री बन्न पुगेको छ भन्ने समस्यामा केन्द्रित रहेको प्रस्तुत लेखमा पुस्तकालयीय कार्यका आधारमा सामग्री सङ्कलन गरिएको छ । नारायण ढकालको ‘इरफान अली’ कथालाई आधार सामग्री र सबाल्टर्न सिद्धान्त तथा पूर्वकार्यसँग सम्बन्धित सामग्रीलाई द्वितीयक स्रोतका सामग्रीका रूपमा ग्रहण गरिएको यस लेखमा गुणात्मक पद्धति अपनाई विषयवस्तु विश्लेषणविधि प्रयोग गरिएको छ । सबाल्टर्न वर्गको पहिचानलाई शिरोपर गर्दै उनीहरूका आवाजलाई सशक्त रूपमा उठाएकाले प्रस्तुत कथा सबाल्टर्नमैत्री रहेको निष्कर्ष यस लेखको रहेको छ ।
An Anthropological Study on the Use of Natural Flavoring Agents in Sri Lankan Traditional Food Culture
Authors: Withanachchi R. K. , Jayatilleke Y. D. , Silva O. T. D.
Published: October 2024

There is no universal definition for the term ‘flavorings’. Yet, spices, herbs, condiments, and seasonings altogether are known as natural flavoring agents, including coloring sources, tart flavorings, preservative spices, aromatic flavorings, and appetizers. In this study, main objective was to identify culinary spices, herbs, condiments, and seasonings that are being used, and their form of usage. This study covered purposively selected 100 Divisions out of 256 Divisions to represent selected Divisional Secretariats. Each 25-household was selected from Divisional Secretariats via snowball sampling method representing 100 D.S. Divisions. The required data were collected from 2500 households through semi-structured interviews. Identified Sri Lankan natural food flavoring agents are divided into three main categories based on their sources: plant-based, animal-based, and mineral-based. 61 natural flavoring agents were identified in this study and this constitutes the highest number of natural flavoring agents used in Sri Lanka. Majority of the identified flavoring agents belonged to the plant-based 55(N) (90%) category. Mineral-based 3(N) (5%) and animal-based 3(N) (5%) natural flavoring agents were identified during this study. In addition, spices 23(N) (38%), herbs 17(N) (28%), seasonings 12(N) (19%), and condiments 9(N) (15%) were also identified in this study. Considerably, flavoring mixtures (thunapaha) play a notable role in Sri Lankan traditional cuisine. Similarly, ‘Thuna’ is one mixture made out of three ingredients (cumin, fennel and coriander) and‘Paha’ is another mixture made out of five lumps (pepper, garcinia, mustard, turmeric and chili). Today, people have limited the use of flavoring agents because of the lack of traditional knowledge and the disappearance of the traditional practices related to cooking from modernized societies.
S4.C2 Calidad del agua del lago de Chapala: una aproximación al riesgo de afectación a la salud por exposición a agua contaminada
Authors: Castellanos Márquez Alejandra , Macías Ascanio Ana Sofía
Published: October 2024

Los datos de calidad del agua de un río o un lago permiten conocer las tendencias espaciales y temporales de los fenómenos de contaminación, así como su relación con las dinámicas del entorno. Además, sirven para sentar las bases de una evaluación de riesgo de afectación a la salud por exposición a agua contaminada, dado que son un insumo para verificar si existe el peligro, o no, o de tener consecuencias negativas sobre la salud de los ecosistemas y las sociedades.
S4.C3 De la injusticia y la violencia epistémicas al derecho al conocimiento
Authors: Larrosa–Fuentes Juan S. , Muñoz Acosta Hernán , Herrera Lima Susana , Quinn Cervantes María , Bernal Loaiza Graciela , Reyes Perales Alma , Gutiérrez Ramírez Alba Sofía
Published: October 2024

La dimensión de derecho al conocimiento (DDC) realiza un abordaje sociocultural de la problemática objeto de la investigación en las comunidades de Mezcala de la Asunción y San Pedro Itzicán que se refiere en este libro (véanse las secciones S1 y S2). El abordaje ha estado centrado en la comprensión de la configuración sociocultural de la crisis sociohídrica, articulando las estructuras, los discursos, las mediaciones y las prácticas, teniendo como orientación central el análisis de las relaciones de poder entre los diferentes actores sociales que configuran esta crisis. El problema central de la dimensión ha consistido en investigar cómo se está produciendo el conocimiento sobre la crisis socioambiental en diversos ámbitos: en el campo científico, en el contexto cotidiano de las personas que viven en las zonas afectadas, en la práctica de los periodistas que reportan sobre el caso y desde los actores sociales —organizaciones de la sociedad civil y líderes comunitarios— que se movilizan para su solución.
S2. Interdisciplina: retos y desafíos
Authors: Verduzco Espinosa Agustín
Published: October 2024

El presente capítulo se propone dar cuenta de una metarreflexión sobre el proceso del trabajo colectivo que implicó el diálogo para la construcción de la metodología interdisciplinaria del proyecto de investigación en su conjunto.
S3.C2 Contexto geográfico y delimitación del área de estudio
Authors: De Alba Martínez Hugo , Rizo Decelis Luis David
Published: October 2024

Las comunidades de Mezcala y San Pedro Itzicán del municipio de Poncitlán, en Jalisco, México, colindan con el lago de Chapala, el más grande del país (véanse los capítulos S3.C1 y S4.C2). A lo largo de su historia Mezcala y San Pedro Itzicán han tenido una relación estrecha con el lago de Chapala, ya que el agua del lago ha sido una fuente importante de alimentos y servido para el riego de los cultivos. Sin embargo, en los últimos años, esta región ha enfrentado problemas de salud pública (Garcia–Garcia et al., 2020), presumiblemente como consecuencia de múltiples factores sociales, ambientales y económicos. Ello se ha vuelto cada vez más común en esas comunidades (Smith et al., 2020).
Corrosion Behavior of Additively Manufactured Stainless Steels in Nuclear Environments
Authors: Goland Micaela , Balbaud Fanny , Fouchereau Alexis , Guerre Catherine , Nguejio Josiane , Puga Beatriz , Rousseau Matthias , Cailloux Thomas , Maskrot Hicham , Pacquentin Wilfried
Published: October 2024

This study examines the corrosion resistance of additively manufactured 316L stainless steel (SS) for nuclear applications across three environments: pressurized water reactor primary water (PWR PW), hot concentrated nitric acid, and seawater. Wire-feed laser additive manufacturing (WLAM) specimens showed oxidation behavior similar to wrought 316L SS in PWR PW, though stress corrosion cracking (SCC) susceptibility varied with heat treatment. In nitric acid testing, laser powder bed fusion (L-PBF) specimens demonstrated superior corrosion resistance compared to conventional SS, primarily due to improved intergranular corrosion resistance resulting from cleaner feedstock powder and rapid solidification rates that minimized grain boundary segregation. Laser metal deposition (LMD) repair studies in seawater environments successfully produced dense, crack-free repairs with good metallurgical bonding that matched the substrate’s mechanical properties while maintaining corrosion resistance. These results emphasize the importance of corrosion testing for additively manufactured components and understanding how their unique microstructures affect performance.
Creep Resistant Martensitic Steels for Operation at High-Temperatures in Power Generation Applications
Authors: Detrois Martin , Hung Chang-Yu , Antonov Stoichko , Jablonski Paul D.
Published: October 2024

Increasing the temperature capabilities of ferritic/martensitic 9-12% Cr steels can help in increasing the operating temperature of land-based turbines and minimize the use of expensive high-temperature alloys in the hot section. A creep resistant martensitic steel, JMP, was developed with the potential to operate at or above 650°C. The design of the alloys originated from computational modeling for phase stability and precipitate strengthening using fifteen constituent elements. Cobalt was used for increased solid solution strengthening, Si for oxidation resistance and different W and Mo concentrations for matrix strength and stability. The JMP steels showed increases in creep life compared to MARBN/SAVE12AD at 650°C for testing at various stresses between 138 MPa and 207 MPa. On a Larson-Miller plot, the performance of the JMP steels surpasses that of state-of-the-art MARBN steel. Approximately 21 years of cumulative creep data are reported for the JMP steels which encompasses various compositions. The relationships between composition-microstructure-creep properties are discussed including characterization of microstructures after >20,000 hours in creep.
Coal-fired Power Plant Boiler Tube Corrosion Inspection Equipment and Remaining Lifetime Evaluation Program
Authors: Han Su Ji , Lee Han-sang , Min Hae-ryun , Lee Gil Jae , Lee Seung Wook , Kim JeongTae
Published: October 2024

This paper discusses the design of a prototype for accurately inspecting the degree of wall thinning in boiler tubes, which plays a critical role in power plants. The environment in power plants is characterized by extreme conditions such as high temperatures, high pressure, and ultrafine dust (carbides), making the maintenance and inspection of boiler tubes highly complex. As boiler tubes are key components that deliver high-temperature steam, their condition critically affects the efficiency and safety of the power plant. Therefore, it is essential to accurately measure and manage the wall thinning of boiler tubes.
Metal Temperature Estimation in High-Strength Austenitic Stainless Steels through Precipitation Analysis
Authors: Hashimoto Keita , Arisue Ko , Saito Nobuhiko , Nakamura Tadaaki , Komai Nobuyoshi , Tominaga Kimihiko
Published: October 2024

In order to comprehensively assess creep damage of 18Cr-9Ni-3Cu-Nb-N steel (ASME SA-213 S30432), which is widely used in critical high-temperature regions of heat transfer tubes of ultrasupercritical (USC) boilers, our investigation centered on the σ phase. This phase undergoes formation and coarsening during prolonged thermal exposure. We developed a technique to estimate operational heating metal temperatures by analyzing average particle size of the σ phase (MLAS-EX). By extracting a certain number of σ phase from the largest particle size, it is possible to select the σ phase that nucleated and grew in the early stage of heating. The correlation between the average particle size and the Hollomon-Jaffe Parameter (HJP), a parameter of heating temperature and time, allows precise estimation of the heating metal temperature. Our validation demonstrates that the replica method, which is a nondestructive method and effective for evaluating actual plants, is also applicable. Using our newly developed technique for estimating heating metal temperature, it is possible to predict the remaining creep life of heat transfer tubes based on data related to creep rupture characteristics, working stress and operating time. The developed method has already been successfully applied to evaluate the creep life of several actual boilers.
Microstructure of Modified 9Cr-1Mo Steel Manufactured via Laser Powder Bed Fusion
Authors: Hatakeyama Tomotaka , Sawada Kota , Suzuki Masaru , Watanabe Makoto
Published: October 2024

Modified 9Cr-1Mo steel was manufactured via laser powder bed fusion (LPBF) using gas atomized powders under various building conditions. Dense samples were obtained at an energy density of 111-125 J/mm3. As-built samples were subjected to a normalization and tempering heat treatments. The microstructure of the as-built sample exhibits a duplex structure, comprising coarse columnar δ-ferrite grains and fine martensite grains. In addition, a small amount of retained austenite phase was observed at the interface between δ-ferrite and martensite. The formation of δ-ferrite is attributed to the extremely rapid solidification that occurs during the LPBF process, while martensite is obtained through the phase transformation because of the thermal cycles experienced during the process. The area fraction of δ-ferrite and martensite can be controlled by adjusting the LPBF parameters. Typical as-built microstructure morphology characterized by the columnar δ- ferrite was eliminated after the heat treatments, resulting in a tempered martensitic microstructure that is identical with that obtained through the conventional process. However, an increase in prior austenite grain size was observed when the area fraction of δ-ferrite in the as-built condition was high, due to faster phase transformation kinetics of martensite than that of δ-ferrite during the normalization. This suggests that the prior austenite grain size can be controlled by optimizing the area fraction of δ-ferrite and martensite in the as-built microstructure.
Effect of Induction Coil Configuration for Localized Postweld Heat Treatment of 9% Cr Steel Control Valves
Authors: Nakunchon Matas , Veeranawin Puwadech , Khunphakdee Phuris , Keawkoed Jaturawit
Published: October 2024

Main steam control valves are crucial components in power plants, as they are the final elements in the steam piping system before the steam enters the turbine. If any parts of these valves become damaged, they can severely harm the steam turbines. Recently, power plants have been required to operate under cyclical loading, which increases the risk of cracks in the control valve seats. This is due to the different rates of expansion between the Stellite surface and the underlying Grade 91 steel surface when exposed to high temperatures. To ensure a reliable power supply, power plants cannot afford long downtimes, making on-site service essential. This paper presents an on-site technique for post-weld heat treatment (PWHT) of Stellite seats. By using a heating pad arrangement and an induction heater, the required PWHT temperature of 740°C, as specified in the welding specification procedure (WPS), can be achieved. This method allows for on-site valve seat repair and can be applied to other power plants as well.
Flow Accelerated Corrosion Investigation and Mitigation in a Heat Recovery Steam Generator
Authors: Khunphakdee Phuris , Limpanichkul Sarayuth
Published: October 2024

Recently, single-phase flow accelerated corrosion (FAC) has been found extensively in Thailand, especially in single shaft combined cycle power plant heat recovery steam generators, the design of which are compact and cannot be easily accessed for service. This takes at least one week for repairing and costs at least half a million dollar per shutdown. In this paper, the investigation of the single-phase FAC in a high-pressure economizer of a combined cycle power plant is demonstrated. Water chemical parameters such as pH and dissolved oxygen are reviewed, the process simulation of the power plant is performed to capture risk areas for the FAC. A computational fluid dynamics study of the flow is done to understand the flow behavior in the damaged tubes next to an inlet header. Some modifications such as flow distributor installation and tube sleeve installation were performed for short-term solutions. Moreover, new economizer headers are designed with low alloy material to mitigate the problem. The installation process of the newly fabricated headers is finally described. The findings in this paper serve as a guideline for FAC risk assessment, FAC investigation and mitigation, and service in compact heat recovery steam generators.
Component Testing under Cyclic Operation Modes for Martensitic Steels and Ni-based Alloys in the HWT3 Power Plant Test Loop
Authors: Klenk Andreas , Friedrich Maximilian , Metzger Klaus
Published: October 2024

This paper reports on the latest in a series of projects aiming at the qualification of new and proven materials in components under a severe service environment. In the initial stages of the project (HWT I & HWT II), a test loop at Unit 6 of the GKM Power Plant in Mannheim was used to study the behavior of components for advanced ultra-supercritical (A-USC) plants made from nickel alloys at 725 °C under both static and fluctuating conditions. Due to recent changes in the operation modes of existing coal-fired power plants, the test loop was modified to continue operating the existing nickel components in the static section while applying thermal cycles in a different temperature range. HR6W pipes and valves were added to the bypass of the static section, and all components in the cyclic section were replaced with P92, P93, and HR6W components. The test loop achieved approximately 9000 hours of operation and around 800 cycles with holding times of 4 and 6 hours. After dismantling the loop, nondestructive and destructive examinations of selected components were conducted. The accompanying testing program includes results from thermal fatigue, fatigue, thermal shock, and long-term creep tests, focusing on the behavior of base materials and welds, particularly for HR6W, P92, P93, and other nickel-based alloys. Additionally, test results on dissimilar welds between martensitic steel P92 and nickel alloys A617 and HR6W are presented. Numerical assessments using standardized and numerical lifetime estimation methods complement the investigations. This paper provides insights into the test loop design and operational challenges, material behavior, and lifetime, including advanced numerical simulations and operational experiences with valves, armatures, piping, and welds.
Investigation of Cold-spray Performance for Cleaning and Repair of Dry Cask Storage System (DCSS) Canisters within a Characteristic Confinement
Authors: Lacy JP , Tatman Jon , Hargadine Mitch , Chu Shannon , Johnson Kyle , Beard Jamie
Published: October 2024

Extended storage of spent nuclear fuel (SNF) in intermediate dry cask storage systems (DCSS) due to lack of permanent repositories is one of the key issues for sustainability of the current domestic Light Water Reactor (LWR) fleet. The stainless steel canisters used for storage in DCSS are potentially susceptible to chloride-induced stress corrosion cracking (CISCC) due to a combination of tensile stresses, susceptible microstructure, and a corrosive chloride salt environment. This research assesses the viability of the cold-spray process as a solution to CISCC in DCSS when sprayed with miniature tooling within a characteristic confinement in two different capacities: cleaning and coating. In general, the cold-spray process uses pressurized and preheated inert gas to propel powders at supersonic velocities, while remaining solid-state. Cold-spray cleaning is an economical, non-deposition process that leverages the mechanical force of the propelled powders to remove corrosive buildup on the canister, whereas the cold spray coating process uses augmented parameters to deposit a coating for CISCC repair and mitigation purposes. Moreover, both processes have the potential to induce a surface compressive residual stress that is known to impede the initiation of CISCC. Surface morphology, deposition analysis, and microstructural developments in the near-surface region were examined. Additionally, cyclic corrosion testing (CCT) was conducted to elucidate the influence of cold-spray cleaning and coating on corrosion performance.
The Development of Weldable Nickel-Based Superalloys and Technologies for Repair and Additive Manufacturing of Turbine Engine Components
Authors: Gontcharov Alexandre B. , Lowden Paul
Published: October 2024

High gamma prime Ni-based superalloys comprising ≥3.5 % Al are difficult to weld due to high propensity of these materials to weld solidification, heat affected zone liquation, and stress-strain cracking. In this study the root cause analysis of cracking and overview on the developed weldable Ni-based superalloys for repair of turbine engine components manufactured from equiaxed (EA), directionally solidified (DS), and single crystal (SX) materials as well as for 3D AM is provided. It is shown that the problem with the solidification and HAZ liquation cracking of turbine engine components manufactured from EA and DS superalloys was successfully resolved by modification of welding materials with boron and silicon to provide a sufficient amount of eutectic at terminal solidification to promote self-healing of liquation cracks along the weld - base material interface. For crack repair of turbine engine components and 3D AM ductile LW4280, LW7901 and LCT materials were developed. It is shown that LW7901 and LCT welding materials comprising 30 - 32 wt.% Co produced sound welds by GTAW-MA on various SX and DS materials. Welds demonstrated high ductility, desirable combination of strength and oxidation properties for tip repair of turbine blades. Examples of tip repair of turbine blades are provided.
Sigma Embrittlement Evaluation Test for Dissimilar Welding Between F6NM and FXM-19
Authors: Osafune Ryoji , Tate Stephen , Leiss Jamison
Published: October 2024

In dissimilar welds between martensitic stainless steel F6NM and nitrogen-strengthened austenitic stainless steel FXM-19, type 209 austenitic welding consumables are used to align with the mechanical properties and chemical composition of FXM-19, with F6NM welds requiring post-weld heat treatment (PWHT) to restore ductility and toughness, raising concerns about sigma embrittlement in ER209 butter welds. This study investigated the mechanical properties and microstructure of F6NM+FXM-19 dissimilar welds, finding no detrimental sigma phase formation in the butter (PWHT) and groove weld metal (as welded) across various welding processes, indicating no sigma phase transformation due to PWHT. Submerged arc welding (SAW) and gas tungsten arc welding (GTAW) demonstrated good mechanical properties, while Gas Metal Arc Welding with 100% Ar gas shield (GMAW 100% Ar) could not be properly evaluated due to weld defects. SAW and GTAW were deemed suitable for this dissimilar weld joint, with several welding processes providing acceptable results using ER209 filler material for fabricating pressure vessels requiring F6NM to XM-19 joints.
Weld Process Effects on Fatigue Performance in the Repair of Coke Drums
Authors: Payne Ronald
Published: October 2024

Coke drums experience failures in through-wall cracking throughout their operating life, resulting from low cycle fatigue. Coke drums are typically fabricated from Chrome Moly (CrMo) steels. This study was performed on P4 (1.25Cr-0.5Mo) base material using ER70S-B2L and Alloy 625 (ERNiCrMo-3) filler materials. Specimens were welded with the temper-bead/controlled deposition welding technique. The weld processes used were HP-GTAW, GMAW and SMAW. The fatigue performance, HAZ hardness and toughness of the weld samples was evaluated. The HP-GTAW welds exhibited an order of magnitude improvement in fatigue performance when compared to the other weld processes using ER70S-B2L filler material. The HP-GTAW welds also exhibited improved HAZ hardness and toughness when compared to the other weld processes. This presentation will introduce the HP-GTAW process, its features, and benefits and where it is applied in Coke drum repair welding. Comparative test results of the different weld processes for fatigue performance, HAZ tempering, and toughness will also be presented.
Summary of Structural Alloy Compatibility in Supercritical CO2 at 450°-800°C
Authors: Pint Bruce A. , Pillai Rishi , Keiser James R.
Published: October 2024

Supercritical CO2 (sCO2) is of interest as a working fluid for several concepts including the direct- fired Allam cycle as a low-emission fossil energy power cycle. Over the past 10 years, laboratory exposures at 300 bar sCO2 have found reasonably good compatibility for Ni-based alloys at <800°C, including an assessment of the sCO2 impact on room temperature mechanical properties after 750°C exposures. However, initial screening tests at 1 and 20 bar CO2 at 900°-1100°C showed poor compatibility for Ni-based alloys. In an open cycle, the introduction of 1%O2 and 0.1- 0.25%H2O impurities at 300 bar increased the reaction rates ≥2X at 750°C. At lower temperatures, steels are susceptible to C ingress and embrittlement. Creep-strength enhanced ferritic steels may be limited to <550°C and conventional stainless steels to <600°C. Two strategies to increase those temperatures are higher Ni and Cr alloying additions and Al- or Cr-rich coatings. Alloy 709 (Fe- 20Cr-25Ni) shows some promising results at 650°C in sCO2 but reaction rates were accelerated with the addition of O2 and H2O impurities. Pack aluminized and chromized Gr.91 (Fe-9Cr-1Mo) and type 316H stainless steel show some promise at 600°-650°C but further coating optimization is needed.
Computational Approach To Predict Solidification Cracking Susceptibility in Welding Filler Metals
Authors: Riffel Kaue C. , Marques Igor J. , Leon-Henao Henry , Ramirez Antonio J. , McCracken Steve , Tatman Jonathan
Published: October 2024

Solidification cracking (SC) is a defect that occurs in the weld metal at the end of the solidification. It is associated with the presence of mechanical and thermal stresses, besides a susceptible chemical composition. Materials with a high solidification temperature range (STR) are more prone to the occurrence of these defects due to the formation of eutectic liquids wetting along the grain boundaries. The liquid film collapses once the structure shrinks and stresses act during the solidification. Thus, predicting the occurrence of SC before the welding process is important to address the problem and avoid the failure of welded components. The nuclear power industry has several applications with dissimilar welding and SC-susceptible materials, such as austenitic stainless steels, and Ni-based alloys. Compositional optimization stands out as a viable approach to effectively mitigate SC in austenitic alloys. The integration of computational modeling into welding has significantly revolutionized the field of materials science, enabling the rapid and cost-effective development of innovative alloys. In this work, a SC resistance evaluation is used to sort welding materials based on a computational fluid dynamic (CFC) model and the alloy's chemical composition. An index named Flow Resistance Index (FRI) is used to compare different base materials and filler metals as a function of dilution. This calculation provides insights into the susceptibility to SC in dissimilar welding, particularly within a defined dilution range for various alloys. To assess the effectiveness of this approach, the relative susceptibility of the materials was compared to well-established experimental data carried out using weldability tests (Transvarestraint and cast pin tear test). The FRI calculation was programmed in Python language and was able to rank different materials and indicate the most susceptible alloy combination based on the dilution and chemical composition.
Creep Behavior of Austenitic Steels in CO2 and the Effect of Specimen Thickness
Authors: Rozman Kyle A. , Oleksak Richard P. , Doğan Ömer N.
Published: October 2024

Steels have a proven track record of safe operation in steam power plants for decades. Interest in developing supercritical CO2 power cycles as a more efficient and sustainable alternative to steam cycles has driven a need to understand steel performance in these new environments. In particular, the potential of the high temperature CO2 environment to influence the creep behavior of the steel must be determined. Prior research on this topic between the 1960s and 1980s found conflicting conclusions, but nevertheless raised the possibility that carburization during CO2 exposure may strongly affect the creep behavior. This raises concerns particularly for thin-sectioned components such as compact heat exchangers, where even small rates of carburization can become problematic over long operating lifetimes. To shed light on this issue, this research investigates the creep behavior of austenitic stainless steel 347H and 309H (a higher Cr alternative) at 650°C. Specimens of 0.5, 1.0, and 2.0 mm thickness were tested to further assess the effect of steel thickness. Both steels show a reduction in creep life in CO2 relative to air, with 309H showing slightly better performance than 374H. Analysis is ongoing to determine the reason for degraded creep properties.
Effects of Chemical Composition and Heat Treatment on Creep Properties of ASME Grade 91 Type Steel
Authors: Yaguchi Masatsugu , Hamaguchi Tomoaki , Miki Kazuhiro , Nomura Kyohei , Komai Nobuyoshi
Published: October 2024

The effects of chemical composition and heat treatment on the creep properties of ASME Grade 91 type steel were experimentally investigated using materials whose chemical compositions and heat treatment conditions in the steel making process were completely controlled. Regarding chemical composition, only the Al, Cr, and Ni contents were systematically varied while keeping the contents of the other elements and heat treatment conditions constant. Regarding heat treatment, the normalizing and tempering temperatures were varied while keeping the contents of chemical components constant. The creep tests of materials were performed for approximately up to 50,000 h at 650°C. The creep strength of Grade 91 type steel decreased with increasing Al content under the test conditions of short-term to long-term range. On the other hand, the effect of Cr content on the creep life of Grade 91 type steel depended on the stress or time range, and the creep strength of the steel decreased at high Cr contents under test conditions of only the longterm range. No effect of Ni content on the creep life of the materials was observed in the test data obtained in this study. As creep tests are currently being conducted at 625°C and 60 MPa, which are conditions closer to the actual service conditions of main steam piping at ultra-super critical power plants, the creep deformation data at present indicate that the above trends hold true in the long-term range. Regarding the effect of heat treatment, the creep life of the materials tended to increase with increasing normalizing temperature or decreasing tempering temperature. The results obtained in this work indicate that within the scope of the material standards for Grade 91 type steel, the effect of chemical composition on creep life is greater than that of heat treatment.
Rejuvenation and Life Assessment of IN 738 Blades after Long-Term Service
Authors: Yang Sungho , Kim Sanghun , Kim Hyosung , Park Junsu
Published: October 2024

Gas turbine blades are operated in a high temperature and a high pressure. In order to cope with that harsh condition, the blades are made of Nickel based superalloys which show excellent performance in such environment. Manufacturers of the blades usually provide the standards for the blade inspection and replacement. According to their guide, the blades are replaced after 3 times of operations and 2 times of refurbishments. Howsoever, purchase the new blades is always costly and burdensome to the power plant owners hence, the assessment of the blade lifespan and the rejuvenation of the degraded blades are indeed crucial to them. In this study, the optimal rejuvenation conditions for gas turbine blades were derived and verified. In addition to that, the creep durability was evaluated based on the actual blade inspection interval. LCF tests have been carried out on the rejuvenated blade and the result was compared with the fatigue life of the new blades. In order to secure the safety of the rejuvenated blade during operation, a heat flow analysis was performed to simulate the operating conditions of the gas turbine during operation, and the main stress and strain areas were investigated through the analysis results. And then LCF and creep considering the actual operating conditions were evaluated. The calculated life of fatigue and creep life is compared to the hot gas path inspection interval. For the rejuvenated blades, the creep life and the LCF interval were reviewed based on the temperature, stress, and strain acquired by computational analysis. The creep life was calculated as 59,363 hours by LMP curve, and the LCF was calculated as 2,560 cycles by the Manson Coffin graph.
FEATURES OF THE BEHAVIOR OF YAKS OF THE ALTAI POPULATION ON SEASONAL PASTURES OF THE KOSH-AGACH DISTRICT OF THE ALTAI REPUBLIC
Authors: Bakhtushkina A. I.
Published: October 2024

When studying the peculiarities of the behavior of yaks of the Altai population on seasonal pastures of the high-mountainous region of the Altai Republic, constant observations of yak behavior by seasons of the year were made, and the daily activity of the herd was timed. Studies were conducted on the basis of yak breeding farms of Kosh-Agachsky district. The behavior of yaks on pastures was recorded according to the time of eating vegetation, time of movement, resting and drinking according to the method of V. Velikzhanin (1975). The obtained data indicate that in all seasons of the year, Altai yaks use the available pastures quite effectively. Thus, in winter, at air temperatures from -15 to -20°C, yaks graze for 12-14 hours (50-58% of the daily cycle). Rest periods during the daytime are short, 2-3 hours, and at night yaks rest for a longer period of time, 8-9 hours (33-37 % of the daily cycle). In the spring period, animals graze for 11-12 hours (45-50 % of the daily cycle), resting for 10 hours, watering for 0.3 hours. In the summer grazing period, on days with high temperatures, yaks graze mainly in the morning and evening hours. On hot days, yaks prefer to rest during the day and graze most of the time at night, resting for only 2-3 hours (grazing takes place from early morning to 12-13 h). On autumn pastures yaks graze mainly in the daytime - 10-11 hours (42-46 % of the daily cycle), resting for an average of 3.5 hours (14.5 % of the daily cycle). At night, grazing takes only 3-4 hours. Thus, the time spent directly on grazing averages 58.3 in spring, 60.4 in summer, 58.3 in autumn and 54.0 % of the total time spent on pastures in winter.
DETECTION OF TILAPIA DNA IN FISH PRODUCTS BY REAL-TIME PCR
Authors: Krasnikova M. S. , Bryusova M. B. , Kozlova A. D. , Gorbacheva N. S. , Dolinskaya K. G. , Yatsentyuk S. P.
Published: October 2024

A method has been developed for the detection and semi-quantitative assessment of tilapia content in fish products using polymerase chain reaction in real time in order to identify facts of substitution of more valuable and expensive fish species with tilapia. The method is based on the use of multiplex PCR to identify a fragment of the rhodopsin gene specific to tilapia genera Oreochromis, Sarotherodon and Coptodon with simultaneous amplification of internal endogenous control. A comparison of methods for DNA extraction from several types of fish products was carried out. It has been shown that precipitation and sorption extraction methods can be used to isolate DNA, and the express method can be used to isolate DNA from samples of single-component products (minced meat and fillet) in order to reduce the time spent on studying these samples. Examining a control panel of DNA samples from various fish species, the method showed 100 % specificity. The absolute sensitivity limit of the method for identifying tilapia genetic material was 200 copies/reaction. The detection limit of the method was 0.05 wt%. The method was approved by testing 83 samples of single-component and 28 samples of multi-component fish products selected from various retail outlets in Moscow and the Moscow region. Two samples contained tilapia DNA that was not declared in the product. The proportion of tilapia DNA detected was in the range of 0.1 % - 1 %, that may indicate accidental contamination during production. The existing requirements for the labeling of fish products are discussed in connection with the admissibility of such impurities. The proposed methodology can be used to monitor the correct labeling of fish.
AN INTEGRATED APPROACH TO FORMING REGIONAL COMPETITIVENESS BASED ON IMPROVING PERSONNEL POLICY
Authors: Kuznetsova I. G. , Val O. M.
Published: October 2024

The article presents the development of a comprehensive approach to the formation of the region’s competitiveness through the improvement of personnel policy. The role of human resources in the development of the agro-industrial complex is considered, the existing labor potential is analyzed, the features and patterns of its development in the conditions of the Far North are identified. Practical recommendations are offered for improving the personnel policy in order to create a favorable environment for attracting and retaining young people in the region. A model is proposed based on ensuring decent wages, housing and increased vacation time. The differentiated principle of payment of funds to young specialists under the age of 25 seems to be very relevant and important in the context of supporting human resources, especially in remote and sparsely populated regions. The main idea of this methodology is to use an integrated approach to the formation of a motivation system for young specialists, which includes several key aspects. Differentiated amount of payments - the introduction of different rates depending on the level of qualification of a specialist. This will not only increase the attractiveness of different professions, but also create incentives for further education and advanced training. Geographical factor – the use of a correction factor for lifting and monthly allowances will make the payment system fairer and more adaptive to working conditions in different regions, especially in those where life and work are associated with great difficulties. A factor of 1.6 will help attract and retain specialists in hard-to-reach areas, including in the Far North. Stimulating professional growth – emphasizing the importance of education and qualifications as key factors in increasing the value of an employee will serve as an incentive for development and advancement in the profession. This approach is aimed not only at attracting young specialists, but also at retaining them in the region, which, in turn, will contribute to the sustainable development of the regional economy and an increase in the general standard of living of the population. These measures will help increase the number of qualified personnel, affect the overall socio-economic situation in the region, and create preconditions for improving infrastructure and quality of life.
Ensuring quarry safety: integrating rockfall barriers and bench-slope engineering for effective protection
Authors:   Department of Earth Resources Engineering, Faculty of Engineering, University of Moratuwa, Sri Lanka, Nanayakkara C. , Dassanayake A. , Chaminda P.
Published: October 2024

A single rock piece or several rock boulders getting detached and displaced from their initial position followed by free falling, sliding, bouncing, rolling, and deposition creates a rockfall incident [1]. Rockfalls are characterized by a greater destructive potential, owing to higher mobility and energy [2]. Recent instances including the Great Orme rockfall, in North Wales, UK (2023), Yosemite National Park rockfall in California, USA (2022), and the Glacier National Park incident in Montana, USA (2019) highlight their catastrophic nature. They not only interrupt the daily essentialities such as travel and transportation but also cause property damage as well as loss of life [3], [4], [5] (Figure 1). A rockfall is triggered by a natural or an anthropogenic alteration of the forces acting on a rock mass under stable conditions. Natural processes include weathering, earthquakes, formation of discontinuities, plant roots penetrating the rocks, rainfall, freeze-thaw cycles, and long-term deformations in the rock mass. Also, there is a significant contribution of human interventions such as slope cutting, blasting, heavy vehicle, and machinery operations to rock movements [1], [2]. Due to the prevalence of such activities, quarries rank top among the sites that are susceptible to frequent rockfall hazards [6], [7]. Given the critical nature of this issue, constant efforts have been made to devise an effective solution, incorporating expertise in geo-technology and engineering. There are two distinct engineering approaches, respectively, to prevent and mitigate rockfall as detailed in Figure 2. Most often, a combination of those two techniques is adopted in many quarry sites to enhance effectiveness [2].
Insights from grey literature that could facilitate research and sustainable development of the Bolgoda ecosystem
Authors:   Department of Earth Resources Engineering, Faculty of Engineering, University of Moratuwa, Sri Lanka, Jayawardena C. , Seneviratne T. ,   Library, University of Moratuwa, Sri Lanka
Published: October 2024

Bolgoda ecosystem has the largest natural lake and freshwater body in Sri Lanka located on the southwest boundary of Colombo District and covering two-thirds of Kalutara District. It is also listed as “one of the 1001 natural wonders of the world one must see before you die [1].” According to the Millennium Ecosystem Assessment (MEA) [2], an ecosystem such as Bolgoda should be providing; Provisioning services (food and water etc.), Regulating services (climate and disease control etc.), Supporting services (nutrient cycling and crop pollination etc.) and Cultural services (recreational, and spiritual benefits etc.). Furthermore, the socio-economic and environmental benefits from Bolgoda could be crucial to achieve the SDG-11, which is to make cities inclusive, safe, resilient and sustainable [3]. Additionally, higher educational institutions and schools, nestled with this ecosystem or in the neighborhood gets an opportunity to embrace and explore its dynamics such as habitat change, responses to invasive alien species, over-exploitation and pollution, that could provide valuable and insightful information for conservation and sustainable development.
FACIAL GROWTH PATTERNS BY J. JARABAK IN PATIENTS WITH DISTAL BITE AND THEIR DIAGNOSTIC VALUE
Authors: Doroshenko S.I. , Opekha O.Y. , Volkova V.V.
Published: October 2024

Purpose. To determine the features of the structure of the facial skeleton in patients with DB, taking into account its growth patterns and rotation.
Methods. To study the features of the structure of the facial skeleton in patients with distal bite, cephalometry was used. The analysis of cephalograms was carried out using the J.Jarabak method, which allowed to determine the facial growth pattern and its rotation in each particular patient with distal bite.
Results The recent study has found that in patients with distal bite, the horizontal (49,4%) facial growth patterns with counterclockwise rotation are prevalent, while neutral(28,5%) and vertical facial growth pattern with rotation clockwise was (21,7%). Determination of the facial growth pattern in patients with distal bite has allowed to differentiate the hereditary forms of distal bite from the acquired, dentoalveolar forms the skeletal system. These cephalometric data, together with clinical data, allow optimizing differential diagnosis and the choice of rational treatment for patients with distal bite.
Conclusions. Definition of the facial growth patterns for J.Jarabak in patients with distal bite is used as the main diagnostic criterion for the differential diagnosis of this dentoalveolar anomaly and for choosing a treatment method and predicting its outcome.
Beyond Numbers: Stories of Gender Equality in and through Parliaments
Authors: Ahrens Petra , Erzeel Silvia
Published: October 2024

Parliaments play a central role in shaping the laws, policies and budget allocations that are required to meet the needs of diverse citizenries. Yet just like other state institutions, parliaments have long reflected and perpetuated the gender inequalities in wider society. International IDEA has long advocated and supported more inclusive, representative, and responsive parliaments, including in terms of gender—not just as a matter of fairness and rights but as an asset for democratic effectiveness, legitimacy, and resilience. This Handbook aims to provide a comprehensive framework for embedding gender sensitivity into the heart of parliamentary functions and processes, while highlighting practical stories of change to inspire and offer a fresh perspective on what enables change in parliaments across the world.
An Adaptive Stabilization Scheme for Autonomous System Oscillations
Authors:   Trapeznikov Institute of Control Sciences, Russian Academy of Sciences, Moscow, Russia, Tkhai V. N.
Published: October 2024

A smooth autonomous system of general form is considered. A global family of nondegenerate periodic solutions by the parameter h is constructed; the period varies monotonically on this family. The problem of stabilizing the oscillations of the reduced controlled system is solved. A smooth autonomous control law with a parameter depending on h is applied, and an attracting cycle is constructed. The results are concretized for an nth-order differential equation. The relation of these results with the conclusions obtained for the reversible mechanical system is established. An adaptive control scheme for the reduced conservative system is proposed to stabilize any oscillation of the family. Some applications are presented.
Different species of yeast alter lifespan and fecundity of Drosophila melanogaster
Authors: Yakovleva E. Y. , Maхimova I. A. , Merzlikin D. S. , Kachalkin A. V. , Markov A. V.
Published: October 2024

Many studies have shown that associated microbiota influences the life history traits of Drosophila melanogaster. The increase in bacterial load reduces lifespan but may increase fecundity. Paradoxically, the influence of yeast microbiota, a key food source for fruit flies, on life history traits is much less studied. In this work, we assessed the influence of natural yeast microbiota, as well as individual yeast species, on lifespan, age-related dynamics of fecundity, and mortality in the control fly line and the fly line with depleted yeast microbiota. We used Starmerella bacillaris, Zygosaccharomyces bailii, and Saccharomyces cerevisiae as individual yeast species for testing. We have shown that the decrease in the amount of symbiotic yeast on the medium, on the surface of the body, or in the fly intestine leads to an increase in lifespan and a decrease in fecundity for flies reared on standard medium. It is consistent with the “disposable soma” hypothesis. At the same time, an increase in lifespan does not compensate for the decrease in fecundity; therefore, the decrease in the number of yeasts leads to a decrease in fly fitness. Inoculation of S. cerevisiae on the medium shifts the reproduction of the control flies to an earlier age, while two other yeast species increase fertility significantly. Inoculation of S. bacillaris and S. cerevisiae (not typical for the microbiota of tested fly lines) on the medium reduces lifespan more than yeast Z. bailii, which is typical for the microbiota of the control line. Yeast microbiota reduces the lifespan of the Drosophila males more than the females. The results indicate deep coevolutionary relationships between the components of the yeast microbiota and the host organism, requiring further studies within the hologenome theory of evolution.