bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Short Stories in English Language Learning Classroom
Authors: Maulidia Annida
Published: March 2024

With compact yet captivating tales, short stories have the potential to be an effective tool for enhancing students' writing skills in English language learning classrooms. As a result, this study article gives a complete overview of the literature on the impact of short stories on language learning. A systematic strategy is used in this study to discover and assess relevant nonempirical studies, theoretical frameworks, and expert perspectives on adding short tales to improve students' writing skills. The data for this research were analyzed, and ten published articles on the subject were reviewed. The findings from the evaluated journal papers show that including short stories in English language education, particularly in intensive reading courses, has a good influence. The findings from the evaluated journal papers show that including short stories in English language education, particularly in intensive reading courses, has a good influence. These findings are useful for educators and curriculum makers who want to improve language learning experiences by using short stories. According to the article, various outcomes were discovered during the evaluation, particularly for teachers and students during teaching and learning.Keywords: Short stories, impact, English, language learning classroom
Step-Wise Changes in the Excited State Lifetime of [Eu(D2O)9]3+ and [Eu(DOTA)(D2O)]- as a Function of the Number of Inner-Sphere O-H Oscillators
Authors: Kofod Nicolaj , Just Sørensen Thomas
Published: March 2024

Lanthanide luminescence is dominated by quenching from high-energy oscillators in the chemical environment. The rate of non-radiative energy transfer to a single H2O molecule coordinated to a Eu3+ ion exceeds the usual rates of emission by an order of magnitude. We know these rates, but the details of these energy transfer processes are yet to be established. In this work, we study the quenching rates of [Eu(D2O)9]3+ and [Eu(DOTA)(D2O)]- in H2O/D2O mixtures by sequentially exchanging the deuterons with protons. Flash freezing the solutions allows us to identify species with varying D/H content in solution and thus to quantify the energy transfer processes to individual OH-oscillators. This is not possible in solution due to fast exchange in the ensembles present at room temperature. We conclude that the energy transfer processes is accurately described, predicted, and simulated using a step-wise addition of the rates of each quenching O-H oscillator. These document the sequential increase in the rate of the energy transfer processes in the quenching lanthanide luminescence, and further provides a methodology to identify isotopic impurities in deuterated lanthanide systems in solution.
Lewis Acid Catalyzed (4π+2σ) Annulation of Bicyclobutanes with Dienol Ethers for the Synthesis of Bicyclo[4.1.1]octanes
Authors: Nicolai Stefano , Waser Jerome
Published: March 2024

Bicyclic carbocycles containing a high fraction of Csp3 have become highly attractive synthetic targets because of the multiple applications they have found in medicinal chemistry. The formal cycloaddition of bicyclobutanes (BCB) has recently been extensively explored for the construction of both bicyclohexanes and bicycloheptanes. Adopting this approach for the synthesis of medium-sized bridged carbocycles has instead remained more limited. We report herein the formal (4π+2σ) cycloaddition of BCB ketones with silyl dienol ethers. The reaction occurred in the presence of aluminium triflate as a Lewis acid catalyst. Upon acidic hydrolysis of the enol ether intermediates, rigid bicyclo[4.1.1]octanes (BCOs) diketones could be easily accessed in good to very good yields. This convenient and scalable procedure was tolerant towards a range of both aromatic and aliphatic substituents on both the BCB substrates and the dienes. The obtained BCO products could be smoothly functionalized through reduction and cross-coupling reactions.
MORPHOMETRIC CHARACTERIZATION OF THREE DIFFERENT HONEYBEES (HYMENOPTERA: APIDAE) SPECIES FROM BANGLADESH
Authors: Islam Nabila Tanzum , Mamunur Rahman Md , Nura Jahan Mst , Ahsanul Haque Md , Raj Karki Pratik , Mehfuz Hassan Saikat Mohammad
Published: March 2024

The honeybee is an eusocial species that plays an important role in conservation, pollination, and environmental protection. In Bangladesh, apiculture has become a profitable venture for the last few decades. Taking into account the potential of different honeybee species in pollinating and producing bee products, knowledge of different species can help maximize the production of bee products and increase pollination. To identify these species using their morphometric characteristics, three samples of honey species, namely Apis mellifera L., Apis cerana F., and Apis dorsata F. were collected to analyze their morphometric characteristics. Approximately 172 worker honeybee samples were collected from 24 colonies in 7 districts of Bangladesh. For each of the collected samples, 22 (22) morphometric characters were measured in the entomology laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University. Analysis of variance was performed to understand the variability of the morphometric characters between honeybee species, which indicated that the morphometric characters are suitable for identifying honeybee species. The principal component analysis delineated three morphometric characters (along with their morphometric characters in parentheses): The distance of the cubular vein a (19), longitudinal length of the forewing (17), and the angle of venation of the forewing B4 (22), which contributed the most to the variance. Classification of honeybee species using multilayer perceptron considering only these three morphometric characters achieved an accuracy of 100% while significantly reducing the overall computation required. The findings of this study can be helpful in identifying the discriminating morphometric characteristics of the honeybee for improving the apiculture sector in Bangladesh.
Analisis dan Kinerja Keuangan pada Perusahaan Manufaktur Subsektor Kosmetik yang Terdaftar di Bursa Efek Indonesia Periode 2015 - 2020
Authors: Ayu Laurenza Andrea Ayu Laurenza , Hazmi Shadrina , Dwiarti Rina
Published: March 2024

Tujuan penelitian ini yaitu untuk mengetahui bagaimana pengaruh likuiditas, solvabilitas, dan struktur modal terhadap kinerja keuangan perusahaan manufaktur subsektor kosmetik yang terdaftar pada Bursa Efek Indonesia periode tahun 2015 – 2020. Populasi pada penelitian ini adalah seluruh perusahaan sub sektor kosmetik yang terdaftar di Bursa Efek Indonesia (BEI) pada periode tahun 2015 - 2020 dengan total 7 perusahaan dan diperoleh sampel sebanyak 7 perusahaan dengan metode purposive sampling. Metode penelitian yang digunakan yaitu metode kuantitatif. Teknik pengumpulan data menggunakan teknik dokumenter dan data yang digunakan merupakan data sekunder.  Hasil penelitian menunjukkan bahwa secara parsial likuiditas yang diukur menggunakan proxy current ratio berpengaruh negatif dan signifikan terhadap kinerja keuangan, solvabilitas yang diukur menggunakan proxy debt to asset ratio tidak berpengaruh signifikan terhadap kinerja keuangan, dan struktur modal yang menggunakan proxy debt to equity ratio tidak berpengaruh signifikan terhadap kinerja keuangan perusahaan manufaktur subsektor kosmetik. Hasil penelitian menunjukkan bawa secara simultan likuiditas, solvabilitas, dan struktur modal berpengaruh signifikan terhadap kinerja keuangan.
Deep convolutional auto-encoders for emotion recognition from facial expressions
Authors: T. Muni Raj
Published: March 2024

One of the unsolved problems in computer vision is recognizing or understanding other people's emotions and feelings. Deep Convolutional Neural Networks (CNNs) have attempted to be effective in addressing emotion recognition issues. The significant level of performance achieved by these classifiers can be attributed to their ability to self-learn a downsampled feature vector that retains abstraction information through filter kernels in convolutional layers. Despite these advancements, challenges persist in capturing subtle and context-dependent emotional nuances, hindering the development of more nuanced emotion recognition systems. Ongoing research explores multimodal approaches, integrating various sensory inputs, to enhance the accuracy and reliability of emotion detection in real-world scenarios. In this paper, we explore the impact of training the initial weights in an unsupervised manner. We study the results of pretraining a Deep CNN as a Convolutional Auto-Multiplexer (CAM) in a greedy layer-wise unsupervised fashion for emotion recognition using facial feature images. When trained with randomly initialized weights, our CNN emotion recognition model achieves a performance rate of 92.16% on the Karolinska Directed Emotional Faces (KDEF) dataset. In contrast, by using this pre-trained model, the performance increases to 93.52%. Pre-training our CNN as a CAM also marginally reduces training time.
Patrimonios vivos y cultura experimental: resignificación del patrimonio a través de la participación de habitantes de El Bordo, Pachuca, México
Authors: Ordaz Bulos David , Sánchez Fonseca Luis Francisco
Published: March 2024

Este trabajo analiza la resignificación del patrimonio a través de un proceso de participación impulsado por habitantes de El Bordo en conjunto con varios colectivos ciudadanos, que tuvo lugar entre el 2021 y 2023. El análisis se enfoca en dos proyectos guiados por la cultura experimental y la noción de patrimonios vivos: el Laboratorio Ciudadano El Bordo (LCB) y el proyecto: Arquitecturas para la Memoria El Bordo, que dio como resultado la construcción del paradero de transporte público llamado “Módulo de Equipamiento Urbano El Bordo” (MEB). 

La localidad de El Bordo está ubicada en la zona norte de la ciudad Pachuca de Soto, Hidalgo, México. Es parte de un paisaje en el que la minería ha operado desde hace más de cinco siglos, y poseé una multiplicidad de elementos patrimoniales que han sido históricamente poco valorados.  El Bordo se encuentra en un contexto periférico que enfrenta profundas problemáticas sociales, reflejadas en la falta de servicios básicos adecuados y el acceso general a los derechos. 

El artículo comienza con una descripción del contexto posminero en el que está El Bordo. Posteriormente, profundiza en las características de la localidad y hace un recuento de las acciones de participación que han ocurrido en ella. Después aborda las nociones de patrimonios vivos y cultura experimental, con foco en las dos iniciativas ya mencionadas: el LCB y el proyecto Arquitecturas para la memoria El Bordo. Y por último, se muestran los aprendizajes de este proceso participativo, que logró la construcción de un bien común a través de la innovación social.
Mitigating violence directed at teachers: a narrative inquiry.
Authors:   , Khanyase Siphelele Fortunate
Published: March 2024

Violence directed at teachers has become a pervasive problem with long-term consequences for teachers and educational outcomes. The issue of violence directed at teachers warrants urgent attention. All those within the school environment, learners, teachers, heads of departments, deputy principals, principals, and support personnel, should feel safe when they are in the school environment. In the same way, learner safety is prioritised within the school environment, teachers’ safety within the classroom and school should also be prioritised so that they can confidently perform their duties. This study is a collective case study of two schools couched within the interpretivist paradigm. This paradigm was suitable for understanding teachers' experiences of violence that is directed at them and the consequences thereof. The study adopted qualitative data generation methods, which included narrative interviews. For the interviews, a purposive sampling of the participants was adopted; there was no set formula rigidly applied to determine the sample size. The study adopted the social cognitive theory. Findings provide evidence of the high rate of violence directed at teachers, especially when accounting for both physical and non-physical forms of violence. The findings established that verbal violence was the most common form of violence that is directed at teachers. Furthermore, it was found that most of the teachers were negatively affected by the violence directed at them, with significant repercussions for their wellbeing. Recommendations made were that there should be a comprehensive approach to addressing violence directed at teachers. Teachers should be trained in classroom management and crisis intervention. Individual intervention strategies should be recommended for learners with serious behavioural problems. Furthermore, there should be an explicit school policy and effective strategy to handle issues of violence directed at teachers. The study concluded that violence directed at teachers is exceptionally prevalent. Moreover, it is complex, multi-dimensional, and dynamic, and it also negatively affects educational outcomes. Mitigating violence directed at teachers should a critical component of school violence programs.
Effects of Different Priming Treatments on The Germination and Growth of Okra (Abelmoschus esculentus L.)
Authors: Alam Md. Mahbub , Khan Mujibur Rahman , Hossain Muhammad Sajjad , Sultana Mst. Sadia , Anjum Md. Tanvir
Published: March 2024

The study was designed to overcome the low germination of okra seed and to assess the effects of different seed priming treatments on okra (Abelmoschus esculentus) seedlings, which were encompassed nine treatments: control, hydro priming, SMP-sand metrix priming, H2SO4 - 40%, H2O2 - 2%, NaCl - 3%, KCl - 3%, CaCl2 - 3%, and KI - 1%. A randomized complete block design was used with three replications. Germination percentages, germination speed index (GSI), seedling vigor index (SVI), and relative growth rate (RGR) were measured. The highest germination percentage (89.77%) and GSI (9.6) were observed with (H2O2 - 2%). T3 (H2SO4 - 40%) exhibited the highest SVI (0.7), indicating robust seedling health. Additionally, H2O2 - 2%. demonstrated the longest root and shoot length (11.7 cm and 14.2 cm, respectively) and highest seedling fresh weight (0.87 g). Treatment with H2SO4 - 40% displayed the highest dry weight (0.18 g). Notably, H2O2 - 2% treatment significantly enhanced germination and growth compared to the control. These findings underscore the potential of seed priming, particularly H2O2 - 2%, in enhancing okra seedling growth and development, offering valuable implications for crop productivity and establishment.
Clinical characteristics and outcome of genitourinary tuberculosis in Balochistan: An observational study.
Authors: Irfana Hassan  , Abdul Rehman Khan  , Zohra Samreen  , Tahira  , Khalil Baloch  , Abdul Zahir
Published: March 2024

Objective: To make aware that the healthcare professionals should diagnose GUTB as early as possible to avoid the grave side effects of untreated cases as it can lead to the gross structural abnormalities in the Genito urinary system. Study Design: Single Center Observational study. Setting: Tertiary Care Medicine Unit in Baluchistan, in BMCH Teaching Hospital. Period: 1st January 2012 to 31st Dec 2022. Material & Methods: Total 118 patients were enrolled in the research and patients were taken a detailed history, they went through physical examination, then they went they underwent through different diagnostic modalities as per the availability in indications. The diagnosed cases were treated and the follow up was done the mean duration for the follow up was around two years. Results: All individuals received interventions primarily involving anti-tuberculosis medications. Three patients had bilateral fallopian tubes obstruction who went under laparoscopy and later on 1 couple opted for IVF, for infertility. Anti-TB drug therapy resulted in severe adverse reactions in 8 individuals. Among them, two female patients experienced the formation of a thimble bladder accompanied by incapacitating storage symptoms. Additionally, at the time of diagnosis, 4 patients exhibited impaired renal functions, which, fortunately, remained unaltered following the completion of the prescribed treatment. None of our patients went into ESRD, and no death during study was reported due to GUTB. Conclusion: It was concluded in our study that Genito urinary tuberculosis being the second commonest type of extrapulmonary tuberculosis is also common in Baluchistan and it needs to be treated and diagnosed and treated as soon as possible, we also suggest that if the expert diagnostic modalities for the diagnosis of GUTB are not available even the clinical suspicion can be used to diagnose the case and start the treatment.
POTENTIAL FOR THE SPACE SOLAR ENERGY SECTOR DEVELOPMENT IN COMPLIANCE WITH THE SUSTAINABLE DEVELOPMENT PRINCIPLES
Authors: Antoniuk Larysa , Niameshchuk Hanna , Anapriiuk Karyna
Published: March 2024

The subject of the research is the history and peculiarities of the exploration and use of space by governmental institutions and private and commercial entities, which, with the beginning of the space age, has created several significant threats to the further development of humanity, due to non-compliance with the principles of sustainable development. The research methodology is based on reports, guidelines, statistical databases and forecasts of integration groups, specialised governmental and international institutions and their structural units for the study and control of space debris (Organisation for Economic Co-operation and Development, National Aeronautics and Space Administration, European Space Agency, United Nations), as well as the results of research by private companies in the space solar energy sector. The purpose of the paper is to analyse trends in the sustainable development of a globalised society in compliance with the principles of responsible use of outer space and to assess the potential of the space solar energy sector to ensure the sustainability of the competitive position of the world's economies. In today's environment, competitiveness and investment in high-tech industries are the driving forces of development that can lead to a country's transition to a fundamentally new level of development. The issue of efficient use of outer space encourages states to search for new technological opportunities for economic growth and inclusive development. Conclusion. The authors have analysed the trends in the use of space, the prospects for sustainable development of the space economy, its impact on the planet's ecosystem, and the main policy directions to help governments take the necessary measures for long-term planning to achieve sustainable and inclusive development. The publication examines space activities related to space debris reduction policies and sustainable solar energy production from space. The authors of the research developed guidelines for space debris mitigation and considered the benefits of using space solar energy.
Pengaruh Kemudahan, Keamanan, dan Kepercayaan terhadap Loyalitas Konsumen
Authors: Lubis Melsi Diana , Sitorus David Humala
Published: March 2024

Consumers have various considerations when using online transportation services such as Maxim. This research aims to determine the influence of convenience, security, and trust on Maxim’s customer loyalty in Batam. The method used in this research is a quantitative-descriptive method. The data was collected through a questionnaire distributed to respondents who were Maxim consumers. The number of samples for this research is 100 samples where the sampling technique used is the purposive sampling method. The data analysis technique used is multiple linear regression which begins with data quality testing and classical assumption testing before carrying out influence tests and hypothesis testing. Hypothesis testing shows that convenience, security, and trust partially and simultaneously have a significant positive effect on customer loyalty. The results of this research can be a basis for Maxim and other online transportation companies to further increase the company's consumer loyalty in terms of convenience, security, and trust.
Pengaruh Komitmen, Kepuasan Kerja, dan Budaya Organisasi terhadap Organizational Citizenship Behavior Pegawai
Authors: Irnandi Avryan , Wardhani Rike Kusuma , Muttaqien Zaenul
Published: March 2024

Currently, companies or organizations need employees with a supportive attitude because of the higher demands on teamwork. This research aims to determine the partial and simultaneous influence of commitment, job satisfaction, and organizational culture on employee Organizational Citizenship Behavior (OCB). This research is a quantitative study with a sample size of 31 North Kediri Health Center employees, which was determined using a saturated sampling technique. Data analysis methods were carried out using validity tests, reliability tests, classical assumption tests, multiple linear regression analysis, t-tests, F tests, and coefficient of determination tests. Research findings show that commitment and organizational culture partially influence OCB, but job satisfaction does not influence OCB. Apart from that, commitment, job satisfaction, and organizational culture have a significant effect on OCB. This research provides additional information, suggestions, and input useful for agencies, especially regarding commitment, job satisfaction, organizational culture, and OCB.
Carmina non prius audita: estructuras de argumentación y lenguaje poético en las odas de Horacio
Authors: Cristea George Bogdan
Published: March 2024

El artículo trata sobre la relación entre la Lógica y la poesía en las odas de Horacio desde el punto de vista del lenguaje y la argumentación. En un primer nivel, examinamos hasta qué punto las técnicas lingüísticas y argumentativas del poeta concuerdan con las estructuras y estrategias clásicas de la argumentación, pero, en un nivel más profundo del análisis, el artículo tiene como objetivo mostrar cómo la Lógica y la Filosofía se entrelazan con la poesía a través de la estilística y la métrica. El estudio identifica tres tipos principales de discurso argumentativo que se pueden encontrar en las odas horacianas: la demostración, con sus formas fuertes (la inducción) y débiles (petitio principii, la generalización apresurada), la exhortación, que puede basarse en la analogía o ir acompañada de explicaciones breves, y la contraposición de argumentos.
Fotografía, grafiti y memoria: en los límites de lo efímero
Authors: Gardner Nathanial , Galán Montemayor Carmen Fernández
Published: March 2024

Este artículo presenta una definición que permite entender la fotografía como una traducción y como un soporte de la memoria. Construida sobre la teoría crítica y el marco de varios académicos de la semiótica y los estudios visuales, esta definición subraya la habilidad única de la fotografía para narrar lo marginal. Tales narrativas pueden revelar signos y símbolos de lo no hegemónico y ampliar nuestra comprensión de las redes y comunidades escondidas. El ensayo por lo tanto estudia una colección de fotografías como testimonios visuales los cuales fueron creados para brindar una comprensión más amplia del uso del grafiti como fórmula de la memoria en la zona fronteriza de la ciudad de Tijuana. El análisis considera las maneras en que la narrativa visual puede leerse como un lenguaje fotográfico y el uso del grafiti para reafirmar la identidad nacional en las zonas liminales de México.
En el ojo de la pandemia: migración de población argentina a Italia en Clarín y La Nación
Authors: Balsas María Soledad , Messina Giuseppe , Smeriglio Gabriele Paolo
Published: March 2024

A partir del análisis socioeconómico, del análisis socioantropológico de las migraciones y del análisis del discurso, en este trabajo proponemos una aproximación crítica a los discursos que Clarín y La Nación ponen en circulación acerca de la migración de población argentina a Italia durante la pandemia. ¿Cómo se resuelve la tensión entre la delicada situación de Italia y su paradójica configuración como potencial destino migratorio? Los resultados evidencian que: i) la pandemia es vista como un obstáculo para la libre circulación antes que como un riesgo para la propia vida; ii) en la imagen idealizada de Italia se omite la gravedad de la situación sanitaria en destino; y iii) el enunciador se define en función de su carácter de opositor al Gobierno.
Memorias que importan: arte participativo y contranarrativas de la pandemia
Authors: Gutierrez-Portillo Susana
Published: March 2024

En este trabajo se reflexiona sobre la potencia de la intervención cultural participativa para movilizar la memoria y las subjetividades en la producción de contranarrativas sobre el encierro, el confinamiento y la crisis en el contexto de la pandemia por Covid-19. A partir del análisis narrativo, se caracterizan las narrativas maestras difundidas a través de los medios digitales sobre la pandemia y, en contraparte, se analiza la propuesta Diarias Global de la artista mexicana Lorena Wolffer como un proyecto de recuperación de memorias invisibilizadas y acalladas durante la crisis sanitaria. Como hallazgos, se plantea que el arte en esta propuesta participativa es capaz de cuestionar, resignificar y revertir las narrativas de caos, inseguridad, enfermedad y muerte masivamente difundidas durante el periodo de confinamiento.
Artivismo: disputa estético-política por la memoria colectiva
Authors: Amao Ceniceros Melina
Published: March 2024

El objetivo de este artículo es analizar, con base en la teoría bourdieuana, el cruce de dos campos: el arte y el activismo. Esto, para dar cuenta de la emergencia de un campo a identificar como artivismo, el cual visibiliza la compleja relación entre estética y política. Para el análisis, se hace una revisión de propuestas y discursividades de artivistas contemporánexs de México que se posicionan desde una perspectiva feminista, queer y/o decolonial; se problematiza el lugar que ocupa el cuerpo en ciertas prácticas a analizarse como artivistas, y se reconoce la importancia del espacio público para emprender acciones micropolíticas. Finalmente, se concluye que el artivismo es en sí mismo un campo antipatriarcal, anticapitalista y antirracista.
Vedic Computing: A Computing Discipline inspired by Vedic Mathematics
Authors: KUMAR CRS
Published: March 2024

In this paper, “Vedic Computing” is proposed as new computing discipline inspired by Vedic Mathematics with applications in Cryptography, Machine Learning, Computer Vision, HPC, Computer Architecture, Signal processing etc. Vedic Computing, integrates an ancient system of knowledge originating from the Indian subcontinent, offers profound insights into mathematical and computational principles. This paper delves into the foundational concepts of Vedic Mathematics and its relevance in contemporary computing paradigms. By elucidating the sutras (aphorisms) and techniques embedded within Vedic texts such as the Vedas and the Sulba Sutras, we uncover a holistic approach to problem-solving that transcends conventional algorithms. Drawing parallels between Vedic Mathematics and modern computational methods, we identify key areas of synergy and divergence. The innate simplicity and elegance of Vedic techniques lend themselves to optimization and efficiency in diverse computational tasks. Moreover, the holistic nature of Vedic Mathematics fosters a deeper understanding of mathematical concepts, promoting creativity and intuition in problem-solving. Through a comparative analysis with modern computing methodologies, this paper underscores the timeless relevance of Vedic Computing principles. By integrating ancient wisdom with contemporary technology, we unveil novel approaches to algorithm design, data processing, and artificial intelligence. Furthermore, we explore the potential implications of Vedic Computing in emerging fields such as quantum computing and machine learning. In conclusion, this paper advocates for the revival and integration of Vedic Computing principles in modern technology, emphasizing the synergy between ancient wisdom and contemporary innovation. By harnessing the insights of the past, we pave the way for a more harmonious and efficient future in computational science and technology. Vedic Computing is backed by vast literature, scholarly publications, active researchers and practitioners.
Effects of the COVID-19 Pandemic on the Labor Market Outcomes of Women with Children in Mexico
Authors: Juarez Laura , Villaseñor Paula
Published: March 2024

This paper estimates the effects of having children at home on the labor market outcomes of women in Mexico during the first year of the COVID-19 pandemic. Our findings suggest that women with children at home experienced some additional negative impacts on their labor supply immediately after school and daycare closures, compared to women without children. However, such impacts began to revert in the third quarter of 2020. One year after the onset of the pandemic, women with children increased their labor supply relatively more than women without them, despite ongoing school closures, suggesting a dominance of a negative income effect. Effects by the age of children are consistent with the reopening of daycare centers in 2020 not schools. We also find suggestive evidence that, for women employed both before and one year into the pandemic, having children at home induces industry changes and slightly decreases their job formality.
 
JEL Classification Codes: J13; J22
Impact of Various Heat Treatments on the Microstructure Evolution and Mechanical Properties of Hot Forged 18CrNiMo7-6 Steel
Authors: Mandal Paranjayee , Al Mamun Abdullah , Da Silva Laurie , Lalvani Himanshu , Perez Marcos , Muir Lisa
Published: March 2024

Carburizing is a method of enhancing the surface properties of components, primarily made from low to medium carbon steels, such as shafts, gears, bearings, etc. Carburized parts are generally quenched and tempered before being put into service; however, after quenching of carburized parts further annealing and hardening treatments can be employed before final tempering. This work analyses the impact of the two aforementioned heat treatment approaches on the development of subsequent microstructures and mechanical properties of hot forged 18CrNiMo7-6 steel. Moreover, this study aims to understand the impact of normalizing treatments prior to the two aforementioned heat treatment routes. Microstructural and mechanical tests were conducted on four as forged flat cylinder components that received a combination of the abovementioned heat treatments. In general, better microstructure refinement, in terms of prior austenite grain size (PAGS), was obtained for carburized parts that received the intermediate annealing and hardening treatments after quenching and prior to the final tempering. Additionally, further refinement of the martensitic pockets/blocks was observed for parts that did not receive a normalizing treatment prior to carburization. The studied heat treatments appear to have a negligible effect on the mechanical properties of the hot forged flat cylinder components.
Endothermic Generator Advanced Diagnostics
Authors: Kominek Alex D.
Published: March 2024

In the continuing effort to improve the quality and consistency of gas produced from an endothermic gas generator, several enhancements have been developed and implemented to diagnose abnormal operating conditions. Typically the variables monitored, controlled, and alarmed on gas generators were limited to the temperature of the heating chamber and the dew point of the gas being generated. As instrumentation has evolved, additional monitoring has been implemented, reducing the instances of sending “bad” endothermic gas into a process critical furnace. The new diagnostic tools allow predictive maintenance to be applied to endothermic gas generators.
Metallurgical Sample Preparation Study for Compound Layer Examination in Nitrided Components
Authors: Rowan Olga K. , Birky Zachary S.
Published: March 2024

Microstructural examination of a nitrided part is the most commonly used method for evaluating nitriding material and process performance. Microstructural evaluation also helps to validate that the process ran as intended and produced the desired nitrided case characteristics. However, sample preparation is often complicated by the partial or complete breakaway of the compound layer and may affect the accuracy of the conclusions made. A set of experiments was performed to evaluate the effect of two saw cutting methods, the use of metal foil for sample mounting, and the use of Ni plating before cutting. Microstructures of 12 experimental conditions were analyzed. Recommendations were made for the nitrided sample preparation best practice to analyze compound layer uniformity and thickness.
Influence of Vanadium Microalloying on the Microstructure of Induction Hardened 1045 Steel Shafts
Authors: Rothleutner Lee , Van Tyne Chester , Goldstein Robert
Published: March 2024

Vanadium microalloying additions are common in medium carbon ferrite-pearlite steel shafts. The increased load capacity provided by vanadium carbonitride precipitation is beneficial in many applications. Induction hardening can further increase the surface strength of a component; however, the implications of the vanadium carbonitride precipitates on microstructural evolution during induction hardening are unclear. Evidence that vanadium microalloying influences the microstructural evolution of the induction hardened case as well as the case/core transition regions are presented in the current study. Vanadium increases the amount of non-martensitic transformation products in the case while decreasing austenite formation kinetics in the case/core transition region. Observations in induction-hardened shafts were supported by Gleeble physical simulations of computer simulated thermal profiles. Characterization was conducted using scanning electron microscopy, dilatometry, and microhardness testing.
A Novel Integrated Tool for Parametric Geometry Generation and Simulation for Induction Hardening of Gears
Authors: Capone Luigino , Petzold Thomas , Hoemberg Dietmar , Ivanov Dmitry
Published: March 2024

Application of 3D finite element method (FEM) simulation for induction hardening of gears is still a time-consuming and expensive task. The significant cost of a simulation remains in the manual preparation of the 3D description of geometry. In the current work, we propose to complement the numeric simulations with automatic geometry generation based on a parametric representation of a gear and an induction coil. The parameters used to describe a gear are module, pitch diameter, and pressure angle. The circular coil is described by the height, external and internal diameters. FEM computations are implemented to solve magneto-quasi-static Maxwell’s equations. A demonstration of the possibilities of the proposed approach via a parametric study is presented by varying the module of a gear while keeping a constant number of teeth. A heuristic tuning of heating power frequency- time is presented here and compared to the classical semi-analytical equations and 2D simulations.
Successful Application of Intensive Quenching, Including the Elimination of Carburizing
Authors: Rylicki Edward
Published: March 2024

Intensive water quenching (IQ) is not a new technology. It goes back over 50 years in Russia and 18 years in the USA. The use of IQ after induction through-heating on “Limited Hardenability” Steels to eliminate the long carburization cycle for case hardened parts is one of many successful applications of IQ.
A New Standard Guide for Induction Heat Treating – Explanation of ASTM A1100
Authors: Frame Lesley D.
Published: March 2024

After several years’ effort, a new standard guide has been approved and published by ASTM International that will fill a lacunae in the field of induction heat treating. A1100 – Standard Guide for Qualification and Control of Induction Heat Treating, includes a detailed description of the process variables that can affect induction heat treated long products. ASTM A1100 also provides guidance on the creation of manufacturing procedures and evaluation of induction heating operations.
Boriding of AISI 440B Stainless Steel and Coating Characterization
Authors: Bonella de Oliveira Pedro Gabriel , Junior Aureliano Ricardo Tadeu , Edson Mariani Fábio , Edward Totten George , Carlos Casteletti Luiz
Published: March 2024

The AISI 440B (DIN 1.2210, X90CrMoV18) steel is one of the hardest among martensitic stainless steels. This type of steel is used in a variety of industrial applications where wear and corrosion are determinant, such as molds, parts and tools for the automotive and biomedical industries. Their superior mechanical properties are due to its high carbon (0.75-0.95 % C) and chromium (16-18% Cr) contents. Suitable coatings can increase wear resistance and expand these materials usability range. Boride coatings, with their high hardness and wear resistance are good candidates for this purpose. Boride layers were obtained by boriding treatment in a salt bath (a mixture of sodium borate and aluminum). The layer properties, such as hardness, thickness, layer/substrate interface morphology and phases formed are influenced by steel composition. In this work, the layers produced on AISI 440B steel were harder, thinner, with a smoother interface when compared to plain carbon steels due the larger amount of alloying elements. In order to evaluate mechanical properties of borided layers in samples of stainless steel AISI 440B, Optical Microscopy (OM) microstructural analysis, Vickers microhardness tests and micro-adhesive and micro-abrasive wear resistance tests were performed. The layers produced exhibited a hardness close to 2250 HV and excellent wear resistance far superior to that of substrate.
Nitriding and Ferritic Nitrocarburizing Atmospheres - Prediction and Control
Authors: Bernard William J.
Published: March 2024

Numerous trademarked, standardized or proprietary nitriding and ferritic nitrocarburizing recipes and control methods are used in industrial furnaces. Surface Combustion has developed a new tool to predict the in-process composition of nitriding and ferritic nitrocarburizing atmospheres from these different processes. In addition, the activities and potentials of carbon, nitrogen and oxygen can be found, leading to prediction of the associated equilibrium phase on the part surface. The theory behind the tool and the application of the tool to control nitriding and ferritic nitrocarburizing atmospheres will be discussed. An overview of different equipment designs that can use the tool will also be presented.
Effects of Composition, Starting Microstructure, and Tempering Conditions on the Changes in Core Properties after a Simulated Nitride Thermal Cycle
Authors: Klemm-Toole Jonah , Findley Kip , Cryderman Robert , Burnett Michael
Published: March 2024

Dilatometry and transmission electron microscopy were used to characterize the effects of V content, Si content, tempering temperature and starting microstructure on the hardness and microstructural evolution of a 0.4 wt pct carbon steel after a simulated nitriding thermal cycle. When tempered at 500 °C, significant amounts of V are left in solution leading to precipitation during the nitride thermal cycle increasing the hardness and dilation strain. Increases in Si content also lead to higher core hardness after nitriding, but Si does not significantly increase dilation strain during nitriding. Bainite starting microstructures produced less dilation strain during nitriding compared to martensite starting microstructures when tempered at 500 °C.
Low-Pressure Carburizing of Powder Metal Components
Authors: Heuer Volker , Schmitt Gunther , Kauffmann Philipp , Faerber Katharina , Lawcock Roger , Shivanath Rohith
Published: March 2024

Transmission-manufacturers constantly need to adapt their products and manufacturing technologies to meet future’s market and legislation requirements such as cost-efficiency, running-smoothness and drivetrain-agility. Components made of powder metal (“PM-components”) are established in today’s transmission industry as a cost efficient alternative even for high strength and high precision powertrain applications. The PM-material and the applied heat treatment processes have made significant improvements in recent years. One major step in the development was to combine the freedom in alloying-concepts of the PM-technology with the advantages of the Low Pressure Carburizing (LPC) heat treatment process. PM-components must be case-hardened to meet design-intent regarding wear resistance and strength. But when case hardening PM-components using a conventional atmospheric carburizing process, this can lead to serious overcarburizing and even massive carbide-formation. Another major challenge when using the conventional process is to clean PM-parts after the traditional oil-quenching process. Therefore, the process of Low Pressure Carburizing (LPC) combined with High Pressure Gas Quenching (HPGQ) was adapted to the special needs of serial production of PM-components. This heat treatment process offers significant benefits, such as: - no overcarburizing and excessive carbide-formation due to precise diffusion of carbon into the components - reproducible microstructures from part to part and from load to load - clean and shiny parts after quenching - superior control of distortion, - no intergranular oxidation, - better fatigue resistance and - the benefits of an environmentally friendly process. Over the past 25 years, Stackpole and ALD worked on powder metal technology and advanced heat treatment processes. Material, process and equipment have seen significant improvements over the last decades to offer true benefits. This presentation will give an insight into benefits and challenges of PM-components heat treated in low pressure with subsequent gas quenching. The paper refers to the industrial series production of components and it refers to R&D - case studies as well.
Vapor Deposition of Metallic Coatings by Very Low Pressure Plasma Spraying
Authors: Vautherin B. , Planche M.-P. , Bolot R. , Montavon G. , Quet A. , Bianchi L.
Published: March 2024

Very low pressure plasma spraying (VLPPS) has been used to manufacture thin, dense, finely-structured ceramic coatings for various applications. This paper presents the results of work in which VLPPS is used to deposit metal. Aluminum was chosen as a demonstrative material, due to its moderate vaporization enthalpy (38.23 KJ·cm-3), with the objectives of better understanding the behavior of a solid precursor injected into the plasma jet, leading to the formation of vapors, and controlling the factors affecting coating structure. Nearly dense aluminum coatings were successfully deposited by VLPPS at 100 Pa with an intermediate power (45 kW) plasma torch. Optical emission spectroscopy (OES) was used to observe the behavior of the metal powder injected into the plasma jet, and simplified CFD modeling provided a better understanding of thermophysical mechanisms. The effect of powder size distribution, substrate temperature, and spray distance were studied. Coatings were characterized by SEM observations and Vickers microhardness measurements.
Effects of Dry-Ice Blasting On Plasma-Sprayed Thermal Barrier Coatings
Authors: Dong S.-J. , Song B. , Liao H.-L. , Coddet C. , Hansz B.
Published: March 2024

This study assesses the effects of dry ice blasting on the lifetime and durability of thermal barrier coatings (TBCs). Three sets of TBCs consisting of a CoNiCrAlY bond coat and YSZ topcoat were deposited by air plasma spraying, each set with a different dry ice blasting treatment. Different microstructures were obtained in both the bond coat and topcoat depending on blasting conditions. Bond coat oxidation and thermal shock lifetime of the TBC are also shown to vary with the blasting treatment. TBCs where both the bond coat and topcoat are dry-ice blasted proved to be the most durable with the biggest improvement in lifetime. They also exhibited the most regular surface roughness.
High Performance Arc Sprayed Coatings for Active Corrosion Protection in Offshore Applications
Authors: Kroemmer Werner
Published: March 2024

This work assesses various ways of improving the corrosion protection and service life of thermally sprayed coatings used in offshore structures. Test results show that improvement is possible even in the case of Zn-Al15 spray coatings and, that in some cases, coating thickness can be reduced without loss of corrosion protection. Test samples were prepared by arc and cold-gas spraying and some of the coatings were sealed. The protective characteristics of the various coating systems were evaluated in a 25-week cyclic aging test as defined in ISO 20340. The results are compared based on the degree of blistering, rusting, and corrosion penetration at the scratch as well as adhesion to the substrate.
Effects of Spark Plasma Sintering Treatment for Cold-Sprayed Metallic Coatings
Authors: Ito K. , Ogawa K.
Published: March 2024

This study investigates the effects of spark plasma sintering (SPS) on the microstructure and properties of cold-sprayed metallic coatings. Water-atomized Cu powder was deposited on Al 5052 substrates by high-pressure cold gas spraying, and the resulting coatings were treated by spark plasma sintering and annealing heat treatment (AHT) at 200°C, 300°C, and 400 °C. To assess the effects of diffusion generated by pulsed dc power, a vertical load was not applied in the SPS system. In addition, a short duration time was used to inhibit crystal grain growth. Treated specimens were evaluated by SEM, EBSD, and hardness and tensile testing. The findings show that the microstructure and hardness of SPS specimens treated at 300 °C are close to that of AHT specimens treated at 400 °C. Tensile strength, however, is clearly higher in the SPS300 specimens, indicating that pulsed dc power accelerates particle interdiffusion due to Joule heating and electromigration, thereby increasing adhesion strength between particles in the coating.
Mechanical Properties of Cold-Sprayed Ti-6Al-4V Coatings
Authors: List A. , Lyphout C. , Villa M. , Gärtner F. , Klassen T.
Published: March 2024

The present study deals with the production and characterization of Ti-6Al-4V coatings produced by cold spraying. All experiments were performed using nitrogen as the process gas. By systematic variation of spray parameters up to a nitrogen gas temperature of 1000 °C and pressure of 5 MPa, the coatings could be tuned for optimum mechanical properties. Attainable coating properties are described in terms of a newly introduced coating quality parameter based on the ratio of particle velocity to critical velocity. The new parameter, η, is used both to interpret and predict coating properties.
Optional Facilities for Low Pressure Cold Spray
Authors: Shkodkin A. , Kashirin A. , Klyuev O. , Buzdygar T.
Published: March 2024

This paper reviews the capabilities of portable low pressure cold spraying systems and presents examples of the repairs that have been made and the different materials involved. It discusses the recent development of ceramic nozzle inserts that extend continuous operating time to more than 10 h and non-pressurized rotating-vibratory powder feeders that provide higher, more stable powder feed rates for production environments.
Microstructure Influence on Electromagnetic Properties of Thermal Sprayed Ferromagnetic Composites
Authors: Brousse-Pereira E. , Neige J. , Pereira S. , Wittmann-Teneze K. , Adenot-Engelvin A.L. , Bianchi L.
Published: March 2024

In this study, ceramic-matrix composites consisting of elongated metal (CoNbZr) particles in a cordierite (MgAlSiO) matrix were produced by plasma spraying. The metal powder was injected into the plasma jet downstream of the ceramic powder to minimize metal decomposition and oxidation. The microstructure and composition of cermet coatings containing 5, 10, and 20 vol% metal were analyzed by SEM and XRD and their electromagnetic properties were evaluated via saturation magnetization, permittivity, and permeability measurements. As expected, flake-shaped metallic particles were obtained and all coatings exhibited soft ferromagnetic behavior.