bluuebunny/crossref_metadata_2025 huggingface dataset:
ANALYSIS OF FACTORS AFFECTING CAREER SUCCESS OF EXECUTIVE AND NON-EXECUTIVE EMPLOYEES IN THE INSURANCE INDUSTRY IN SRI LANKA
Authors: Ekanayake  , Dissanayake
Published: September 2024

In the competitive and evolving insurance industry of Sri Lanka, the understanding of the determinants of career success is essential for employee retention and overall industry growth. But there are limited studies conducted to explore the factors affecting the career success of employees in the insurance industry in Sri Lanka. To address this gap, the current researcher conducted a study with the primary goal of identifying the factors that influence the career success of both executive and non-executive employees in the Sri Lankan insurance industry. A survey was conducted among 102 respondents selected among the both executives and non-executive employees currently working in the insurance industry of Sri Lanka using a structured questionnaire to gather primary data. The relationship between work-life balance, job stress, job satisfaction, job retention, and career success was analyzed using the regression analysis. As per the results of the regression analysis, work-life balance, job satisfaction, and job retention are positively associated with career success, while job stress has a negative impact. The findings highlight the importance of supportive organizational policies and practices in enhancing career success. Job satisfaction emerged as a key motivator for employees to remain with their organizations, thereby providing the stability required for career advancement. Work-life balance was found to be crucial for maintaining employee well-being and productivity, while job retention was essential for fostering long-term career growth. Conversely, high levels of job stress were detrimental to career success, indicating the need for effective stress management strategies within organizations. Based on these insights, the study recommends that insurance companies in Sri Lanka prioritize initiatives aimed at improving work-life balance, reducing job stress, increasing job satisfaction, and fostering job retention. By addressing these factors, companies can create a supportive and productive work environment that promotes the growth and success of both executive and non-executive employees, ultimately contributing to the overall success of the industry.
THE IMPACT OF PORTFOLIO DIVERSIFICATION ON THE PROFITABILITY OF LICENSED COMMERCIAL BANKS IN SRI LANKA
Authors: Menike
Published: September 2024

Licensed commercial banks are essential for ensuring the stability of any country's financial system. According to the 2022 annual report of the Central Bank of Sri Lanka (CBSL), licensed commercial banks collectively held fifty-five percent of total assets. Portfolio diversification stands as a fundamental strategy for mitigating risk and enhancing returns in the banking sector. Thus, this study aims to investigate the relationship between portfolio diversification and profitability within the realm of licensed commercial banks operating in Sri Lanka. The researcher set out to achieve two research objectives by examining the correlation between the diversification index and profitability. Return on Asset and Return on Equity were used as measurement criterion of profitability. The dependent variable, portfolio diversification, was measured using a diversification index derived from the Herfindahl-Hirschman Index (HHI). A sample of ten listed banks was selected out of twenty-four licensed commercial banks. Secondary data were collected from the annual reports of ten listed commercial banks for the period of 2012 – 2022. A fixed effect model was selected among panel data regression models after conducting the F test, LM test, and Hausman test. The study's findings indicate that the diversification index has an insignificant negative impact on ROA and a significant negative impact on ROE. The equity ratio of banks has a negative, insignificant impact on both ROA and ROE. Bank size has a significant and negative impact on both ROA and ROE. Therefore, the findings of the study demonstrate that diversification negatively impacts both ROA and ROE. The findings from this study hold significant implications for both banking institutions and policymakers in Sri Lanka. Understanding the relationship between portfolio diversification and profitability can inform strategic decision-making within banks, guiding them towards more effective risk management practices and resource allocation strategies. In essence, this study contributes to the existing literature by offering empirical evidence and theoretical insights into the impact of portfolio diversification on the profitability of licensed commercial banks in Sri Lanka.
Pengaruh Komisaris Independen terhadap Pengungkapan Manajemen Risiko: Peran Moderasi Komite Audit
Authors: Primadona Ida Ayu Lidya , Murti Ni Putu Mita Ari , Mahaputra I Nyoman Kusuma Adnyana , Sudiartana I Made , Bagiana I Kadek
Published: September 2024

Penelitian ini mengeksplorasi pengaruh komisaris independen terhadap pengungkapan manajemen risiko dan peran moderasi komite audit dalam konteks perusahaan keuangan dan asuransi di Indonesia. Dengan menggunakan data sekunder dari laporan tahunan perusahaan selama periode 2021-2023, dan menganalisis 147 data observasi melalui analisis regresi moderasi. Penelitian ini menemukan bahwa komisaris independen memiliki pengaruh positif signifikan terhadap pengungkapan manajemen risiko dengan nilai koefisien sebesar 0,7400 dengan p-value 0,0000, yang menunjukkan signifikansi statistik yang kuat. Variabel Komisaris Independen memiliki koefisien 0,0003 dan p-value 0,0030. Komite audit tidak berpengaruh signifikan baik secara langsung maupun sebagai variabel moderasi. Hal ini diketahui berdasarkan nilai variabel Komite Audit dengan koefisien 0,0088 dan p-value 0,5800, serta Interaksi antara Komisaris Independen dan Komite Audit dengan koefisien -0,0002 dan p-value 0,5570, keduanya dinyatakan tidak signifikan secara statistik. Temuan ini menunjukkan bahwa untuk meningkatkan pengungkapan manajemen risiko, perusahaan perlu memperkuat peran komisaris independen serta memastikan komite audit memiliki kemandirian dan keahlian yang memadai. Implikasi dari penelitian ini mencakup rekomendasi untuk praktik tata kelola perusahaan yang lebih baik dengan meningkatkan kemandirian dan keahlian anggota dewan komisaris dan komite audit dan pengembangan kebijakan yang lebih ketat untuk memastikan transparansi dan akuntabilitas yang lebih tinggi.
Aquarela Autista: Aplicativo móvel para o auxílio na coordenação motora fina de crianças com espectro autista
Authors: Nascimento Vinicius O. do , Lopes Átila R.
Published: September 2024

A coordenação motora fina é uma habilidade essencial no desenvolvimento de crianças com espectro autista que, em muitos casos, enfrentam sérias dificuldades motoras. As tecnologias assistivas podem ajudar a minimizar esse problema. No entanto, essas tecnologias ainda são bastante limitadas nessa área. Assim, este artigo apresenta o aplicativo Aquarela Autista, uma ferramenta para auxiliar no desenvolvimento motor fino de crianças autistas, por meio de atividades práticas que exercitam essa habilidade. Além disso, o aplicativo coleta dados das atividades realizadas pela criança e envia para o médico responsável acompanhar o progresso da coordenação motora fina do paciente autista. A ferramenta foi avaliada por um grupo de crianças autistas que participaram de um estudo de caso e validaram o aplicativo em relação a usabilidade e motivação de uso.
Método Computacional Para Automação do FAMACHA em Cabras e Ovelhas
Authors: Rocha Mauricio Benjamin da , Sarmento José Lindenberg Rocha , Santosa Natanael , Rabelo Ricardo Andrade Lira , Veloso e Silvao Romuere Rodrigues , Carvalho Filho Antônio Oseas de , Araújo Flávio Henrique Duarte de
Published: September 2024

A criação de cabras e ovelhas é crucial para a economia do Brasil, fornecendo insumos, impulsionando o desenvolvimento local e gerando empregos. No entanto, produtores enfrentam desafios na saúde de seus rebanhos devido a parasitas, como o verme do estômago (Haemonchus contortus), que causam anemia e perda de peso, reduzindo a produtividade. O método FAMACHA, utilizado para monitorar a saúde dos rebanhos, é trabalhoso, sujeito a erros humanos e requer treinamento especializado, com interpretações subjetivas que podem resultar em diagnósticos imprecisos e tratamentos inadequados. Este trabalho propõe desenvolver uma metodologia com visão e inteligência computacional para automatizar o método FAMACHA.
Avaliação do Impacto da Utilização do Núcleo Central em SDM-EON com Fibras de 7 Núcleos
Authors: França Jordana B. , Mori Uriel P. , Lacerda Jr Jurandir C. , Soares André C. B.
Published: September 2024

Este artigo avalia a utilização do núcleo central em redes ópticas elásticas com multiplexação por divisão espacial em fibras com 7 núcleos. Destaca-se o problema do crosstalk, onde sinais em núcleos vizinhos interferem entre si. Utilizando algoritmos para o problema RMCSA (Routing, Modulation, Core and Spectrum Assignment), o estudo analisa cenários de alto e baixo crosstalk em diferentes topologias de rede, medindo o impacto através das probabilidades de bloqueio (PBC) e suas causas. Os resultados numéricos indicam que a não utilização do núcleo central proporciona uma diminuição da PBC em até 24% nas topologias e algoritmos considerados.
Abordagem Hierárquica com BERT para Classificação de Documentos Jurídicos Longos: Uma Análise de Técnicas de Agregação de Características
Authors: Silva Jasson Carvalho da , Rabelo Ricardo Andrade Lira , Lima Weslley Emmanuel Martins , Almeida Vitor Augusto Correa Cortez
Published: September 2024

O estudo visa avaliar e implementar técnicas de agregação de características em modelos hierárquicos para lidar com textos longos no domínio jurídico. Modelos baseados em transformers, embora eficazes em vários problemas de Processamento de Linguagem Natural, enfrentam dificuldades devido à sua complexidade quadrática, especialmente com textos que excedem 512 tokens. Para superar esses desafios, o estudo propõe investigar métodos como modelos hierárquicos, estratégias de divisão de texto, atenção local e esparsa, com o objetivo de aprimorar o processamento e a análise desses textos, fornecendo insights valiosos para a compreensão e uso eficaz em contextos jurídicos.
Investigação de métodos de similaridade textual no contexto da avaliação automática de questões discursivas
Authors: Almeida José Augusto O. da S. , Moura Raimundo Santos
Published: September 2024

Este artigo aborda a avaliação automatizada de questões discursivas, um desafio significativo para os educadores devido à sua natureza laboriosa. Apesar dos avanços nessa área, persistem desafios como a oscilação dos modelos, a escassez de conjuntos de dados em português e a diversidade de métodos disponíveis sem um padrão estabelecido. O objetivo deste trabalho é estudar e avaliar diferentes técnicas e ferramentas de similaridade textual para a correção automática de questões discursivas, visando oferecer soluções para os desafios mencionados. Nos experimentos realizados obteve-se um erro médio de 13,9 pontos, considerando uma escala de 0 a 100, para o melhor modelo, o que torna animador utilizar tal abordagem no contexto educacional.
Identificação de Parkinson em Imagens Faciais Usando Modelos de Deep Learning Pré-Treinados
Authors: Pereira Caio B. A. A. , Barros Pedro H. X. R. , Rodrigues José N. A. , Araújo Paulo H. R. , Borges Rodrigo N. , Almeida Kelson J. , Veras Rodrigo M. S.
Published: September 2024

Este artigo avaliou o uso de modelos de deep learning pré-treinados na classificação de imagens faciais para diferenciar entre indivíduos saudáveis e pacientes com Doença de Parkinson (DP). Utilizamos um dataset composto por 340 imagens de pacientes com DP e 358 imagens de indivíduos saudáveis, aplicando técnicas como validação cruzada por grupos com 5 folds, aumento de dados e ajuste fino. O melhor desempenho foi obtido com o modelo DenseNet-201, que apresentou uma acurácia média de 92,77%, F1-score de 92,48% e índice Kappa de 85,33%. Esses resultados sugerem que as CNNs pré-treinadas são promissoras para a detecção de Parkinson em imagens faciais.
Redução de 3-SAT para Subconjunto Independente em Grafos: Implicações e Perspectivas
Authors: Santana Vitor José Ferreira dos S. de , Moura Ericksulino M. de A. , Pereira José Miqueias de A. , Carvalho Juliana Oliveira de , Gonçalves Glauber Dias
Published: September 2024

Este estudo investiga a redução do problema 3-SAT para Subconjunto Independente em grafos, preservando a complexidade NP-completa dos problemas originais. A metodologia utiliza a estrutura matemática do 3-SAT para traduzir cláusulas booleanas em relações gráficas, viabilizando a verificação de conjuntos independentes. Os resultados mostram que esta abordagem pode oferecer soluções eficientes e escaláveis, úteis em verificações de consistência em sistemas especialistas, otimização de circuitos digitais e outros desafios computacionais complexos.
Otimização de Modelos de Regressão para Predição de Peso em Pequenos Ruminantes Utilizando Medidas Corporais
Authors: Araújo Rafael Luz , Silva Lilian Rosalina Gomes , Sarmento José Lindenberg Rocha , Veloso e Silva Romuere Rodrigues
Published: September 2024

A ovinocaprinocultura no Brasil está em expansão, mas enfrenta desafios para equiparar-se à produtividade da bovinocultura. Em pequenas fazendas, a ausência de balanças e os altos custos associados à sua implementação dificultam o controle zootécnico preciso. Este estudo buscou superar esses desafios ao estimar o peso corporal de ovinos e caprinos usando técnicas de regressão otimizadas com Grid Search. Com medidas morfológicas como entradas, o modelo SVR apresentou resultados robustos: um MAE de 3.83, RMSE de 5.43, e R² de 85.0%, competindo diretamente com os principais trabalhos da literatura. Esses resultados promissores contribuem para um manejo mais eficiente e sustentável dos rebanhos, potencializando o setor no país.
Sistema IOT de monitoramento de Colmeias de Abelhas Apis Mellifera
Authors: Marques Raylander , Franco Wellington , Pinheiro Samuel L. , Miranda Joao Isaac S. , Freitas Emannuel Diego G. de , Souza Renato William R. de
Published: September 2024

A adoção da Internet das Coisas (IoT) no setor apícola é crucial para enfrentar os desafios contemporâneos da produção de mel. Este artigo apresenta um sistema de monitoramento para colmeias de abelhas Apis Mellifera, operando em apiários no sertão cearense. Utilizando sensores de temperatura, umidade, peso e um sensor magnético, o sistema transmite dados em tempo real via tecnologia LoRa. Os testes mostraram resultados promissores, reduzindo visitas ao apiário e uma melhor gestão do mesmo pelo apicultor. O projeto é desenvolvido em conjunto com apicultores da região o que permite uma maior proximidade das reais necessidades que a aplicação deve ter, sendo assim possível de ser implementado para os produtores de mel.
English Language Educators as Changemakers: An Asian Perspective
Authors: Anthony Narciso Z. Tiangco Joseph
Published: September 2024

This chapter argues for a rethinking of the role of English language educators. There is money in English language teaching, but an attitude of indifference that English language educators should best focus on the usual business of English teaching alone is not enough in the twenty-first century. The times demand they go beyond their roles as mere transmitters of linguistic and cultural knowledge. To shed light on deeper societal issues challenges the notion that social-cultural and economic entitlement is English language education’s true and primary value. This chapter discusses cases from an Asian perspective, highlighting the transformative journey of non-native English language educators and their students as changemakers. Transcending the traditional boundaries of the English language learning classroom is possible. It can also be most meaningful, especially in appreciation of the historical and geopolitical dynamics of the times.
Intelligent NDT on Used Die/Mould for Remanufacturing
Authors: Wang Zezhong
Published: September 2024

Remanufacturing is an important option for industry waste. As a main source of industry solid waste, industry equipment, such as dies and moulds, needs inspections to progress for further remanufacturing processes. To automate inspections such as ultrasonic testing, there are some challenges in robot control, for example, the orientation of transducer and the moving speed. In this study, a model-based method will be used to control the orientation of the end-effector of the robotic arm based on contact force to control the ultrasonic probe to implement robotic UT. A collaborative robotic arm is used to inspect with better safety and precision. A 6 DOF force/torque sensor is used to measure contact force/torque between the end-effector and the surface. A control software platform based on robot operation system (ROS) is established to control the trajectory of robot both in simulation and real world from scratch. Moreover, reinforcement learning (RL) algorithm is implemented to optimise the trajectory, i.e. the orientation control, the moving speed, and position control, during the surface scanning between each waypoint. The proposed method is verified in the control of robot on point-to-point UT, and it can be used in real-world robotic UT.
The Resource Portfolio: Maximising Investments in Education Innovation
Authors: Green Crystal , Khalil Fares Georges , Ziegler Laren , Gonchigdorj Ariunkhishig
Published: September 2024

In this report, we propose resourcing the implementation of innovations at scale through a more holistic approach to how people share and regenerate the energy to enact innovation and sustain quality education. This approach has significant implications for how public and private funders of education might rethink their strategies for resourcing change, particularly by recognizing the diverse types of resources required to support meaningful transformation. We propose five types of resources that, when employed in combination, can sustain the implementation of education innovations at scale: financial, material, social, values, and time resources. Next, we examine ten cases to develop a deeper understanding of how implementation is being resourced when innovations are reaching scale. We specifically look at what drove the innovators to develop their innovation, or their ‘call to action’; who and what resources helped them on their scaling journey; and where they are headed next to secure resources for a sustainable future. We also highlight how the resource categories outlined above (financial, material, social, values, time) show up in the experiences of the innovators. Expanding the notion of resources beyond tangible assets, such as capital, is essential for fostering creativity and innovation. Elements like play, empathy, and the joy of nature are often undervalued, but they contribute significantly to the generative process. Moving forward, further research is needed to explore innovative financing mechanisms for smaller organisations, enhance teacher professional development, and better utilise evidence in decision-making. To sustain education innovations at scale, we must recognise and integrate diverse resources, both tangible and intangible, while fostering flexible funding mechanisms. A holistic approach, combining financial support with investments in people, values, and time, is essential for creating meaningful and lasting education transformation.
ISO 24543 for AE sensor sensitivity verification - support packages help to implement software scripts
Authors:   Vallen-Systeme GmbH, Vallen Hartmut
Published: September 2024

This paper presents an overview over ISO 24543, the new ISO Standard for acoustic emission (AE) sensor sensitivity verification, published in Sept. 2022.
ISO 24543 is based on the face-to-face setup, where a piezoelectric transmitter generates a known particle motion pulse, stimulating a directly coupled AE sensor.
ISO 24543 gives two procedures, one for the determination of a transmitter’s transmitting sensitivity spectrum, referring to absolute units of nm/V, and one for the determination of the AE sensor’s
receiving sensitivity spectrum, referring to absolute units of V/nm.
ISO 24543 has been developed to replace the face-to-face method that delivers sensitivity spectra referring to units of V/µbar, whereby the units of µbar used for the stimulation of the SUT are neither proven nor reproducible.
This paper introduces two support packages, containing descriptions and examples of software scripts that shall help experts getting their sensor verification setup quickly running.
This presentation also discusses the influence of the sensor’s load on the particle motion at the ransmitter’s output.
The capability of Acoustic Emission features to monitor diamond-coated burr grinding wear and effectiveness
Authors:   Cardiff University, Jessel Tom ,   Cardiff University, Byrne Carl ,   Cardiff University, Eaton Mark J. ,   Cardiff University, Pullin Rhys
Published: September 2024

Within manufacturing there is a growing need for autonomous Tool Condition Monitoring (TCM) systems, with the ability to predict tool wear and failure. This need is increased, when using specialised tools such as Diamond-Coated Burrs (DCBs) for grinding high strength ceramics or glass, in which the random nature of the tool, inconsistent manufacturing methods and high wear rates create large variance in tool life. This unpredictable nature leads to a significant fraction of a DCB tool's life being underutilised due to premature replacement. Workpiece surface damage, increased grinding forces and large-scale diamond grain pullout could all be the result of high levels of runout and in-circularity common within electroplated DCBs. As such it is important to not only monitor the overall tool wear but also tool condition. Acoustic Emission (AE) presents as an indirect on-machine sensing method highly suited to grinding applications. The high frequency range of AE, >20 kHz, prevents machine noise from dominating the acquired signals, isolating the micro-scale machining processes within noises machine environments. AE resulting from the grinding process has the potential to monitor not only tool wear but also runout and circularity. A series of DCB wear tests have been conducted, each consisting of the continuous acquisition of AE during grinding and frequent tool surface measurements. Preliminary results demonstrate AE kurtosis can be seen as an indicator of each tool’s runout, representing the fraction of time the tool and workpiece are in contact during a revolution. As a result, an indirect monitoring system capable of monitoring wear and tool state with AE could be utilised within the manufacturing sector.
Acoustic emission for monitoring of fatigue damage in concrete elements of wind turbine towers
Authors:   BAM Federal Institute for Materials Research and Testing, Pirskawetz Stephan ,   BAM Federal Institute for Materials Research and Testing, Thiele Marc ,   Vallen-Systeme GmbH, Löhr Manuel ,   BAM Federal Institute for Materials Research and Testing, Loewe Anna ,   BAM Federal Institute for Materials Research and Testing, Degener Sebastian ,   BAM Federal Institute for Materials Research and Testing, Herrmann Ralf
Published: September 2024

Wind energy has become an important player in the energy transition in Germany. Towers of onshore wind turbines are often designed as hybrid structures: the lower part is made of prestressed concrete whereas the upper part is made of steel tubes. The tall structures are permanently subjected to dynamic loads. A research project of BAM as part of the joint project WinConFat-Structure focusses on the development of techniques to monitor fatigue damage evolution in the concrete part. Results of a previous project show that a combination of ultrasonic and acoustic emission testing can give an indication for critical conditions near the end of the fatigue life of the concrete. In the ongoing project acoustic emission sensors have been installed at the base and at the transition piece between concrete and steel of a hybrid wind turbine tower. Beside of acoustic emission measurement the sensor spacing allows for measuring the concrete ultrasonic velocity along the circumference in both levels. Additional measurements like strain, temperature, inclination, or acceleration allow for comparison of environmental loads and change of acoustic properties of the concrete. The paper focusses on first acoustic measurements recorded since December 2023 in comparison to operating data of the wind turbine.
Influence of loading conditions on acquired AE signals in biocomposites
Authors:   University of Ljubljana, Kek Tomaž ,   University of Ljubljana, Šturm Roman ,   University of Ljubljana, Bergant Zoran
Published: September 2024

Composite materials are increasingly used in lightweight transportation systems and civil engineering due to increasing weight constraints and installation costs. In the case of transportation systems such as in the aerospace and automobile industries, the use of composite materials reduces the weight, which is reflected in increasing the transportable load and reducing fuel consumption, and therefore the mechanical performance of the material is a very important and desired attribute. Biocomposites reinforced with natural fibers, such as flax, are gaining attention in engineering applications due to their sustainable and mechanical properties.

This paper's research was designed to investigate the AE signals at different loading conditions of V-notched biocomposite specimens. Applying different loading cases, ranging from pure tension to pure shear, provided an understanding of the material's response under diverse stress states. The multi-axial strength and failure characteristics of biocomposites are evaluated. Digital image correlation technique provided measurement of strain fields complemented with AE data. AE signals have proven effective in capturing the onset and progression of different failure sources in composite material.
Studies on a Mobile Acoustic Emission Sensor Verification Device
Authors:   University of Augsburg, Fernandes De Oliveira Junior Adelmo ,   University of Augsburg, Schlech Thomas ,   University of Augsburg, Sause Markus G. R.
Published: September 2024

Despite the fact that there are two ASTM standards, ASTM 1106 for primary calibration and ASTM E 1781 for secondary calibration of acoustic emission sensors, there is no company or institution currently offering calibration services based on these standards due to lack of availability or practical aspects. Another option is CEN ISO/TR 13115, which needs a large volumetric propagation medium leading to similar practical limitations as for the ASTM standards. Many acoustic emission users try to fill the gap of calibration services by using simplified verification standards. However, there is currently no verification standard suitable for using in the field. In that sense, one ambition of the project CalibrAEte is to establish a new standard for primary and secondary calibration that can be implemented in laboratories without a huge invest. Another objective of the project is to establish a verification procedure using a device to verify acoustic emission sensors by a wave-based approach in the field. The proposed approach uses a durable propagation medium that carries the elastic waves from a repeatable source to the sensor under test. This research focuses on such a mobile verification device in the sense that an optimal configuration is proposed. This contribution will present the major aspects and details of an acoustic emission sensor verification setup that can be used not just in the laboratory environment but also in harsh field conditions. It will be shown the performance of the reference sensor developed for this purpose along with the setup itself, which was partially developed by aid of numerical methods. Also, experimental results in different temperature conditions, will be presented to assess the robustness of the setup. It also be presented a sensitivity analysis of the setup using different sensors in different stages of degradation.
Acoustic emission monitoring of a large-scale 50-year-old prestressed concrete bridge girder during an eccentric three-point bending test
Authors:   KU Leuven (Catholic University of Leuven), Van Steen Charlotte ,   KU Leuven (Catholic University of Leuven), Vandecruys Eline ,   Politecnico di Torino, Tondolo Francesco ,   Politecnico di Torino, Lacidogna Giuseppe ,   KU Leuven (Catholic University of Leuven), Verstrynge Els
Published: September 2024

Deterioration of reinforced and prestressed concrete structures is one of the main challenges in structural engineering. As the majority of our infrastructure is built around 1960-1980, most structures have reached or will soon reach their design lifetime, giving rise to more structural problems and costs in the coming decades. It is therefore important to develop efficient assessment schemes allowing to assure the safety and reliability of these existing structures and to estimate their residual lifetime. Within the framework of the Bridge|50 research project, a 50-year-old prestressed concrete bridge showing signs of corrosion damage was decommissioned. The bridge girders were recovered and have been subjected to large-scale load tests with varying loading patterns. This paper presents the results acquired during acoustic emission (AE) monitoring of one of the I-shaped girders during a monotonic three-point bending test with an eccentric point load. The results show that the failure mode and location could be detected based on AE activity and zonal AE localization. The onset of concrete cracking was observed by a decrease in peak frequency of the AE signals. Average frequency (AF) and rise angle (RA) value analysis was used to characterize the crack mode, which shifted from tensile to shear mode during bending.
Acoustic emission monitoring of a laser powder bed fusion process
Authors:   University of Stuttgart, Jüngert Anne ,   Vallen-Systeme GmbH, Thenikl Thomas ,   University of Stuttgart, Hofmann Roman ,   Chalmers University of Technology, Maderner Ludwig ,   University of Stuttgart, Werz Martin
Published: September 2024

Additive manufacturing (AM) metal parts offers opportunities for various industrial applications. From individual production of spare parts for unique mechanical components to prototyping of complex structures, the possibilities of production using the additive manufacturing process are manifold. One common AM technique is the Laser Powder Bed Fusion (PBF-LB/M) process, where a laser is used to selectively melt metal powder and create the parts layer wise as designed in a model. During manufacturing certain defects like pores, cracks and lack of fusion may be created in the built parts. As AM parts often have complex geometries, a postprocess non-destructive testing is difficult or even not possible. Thus, different optical monitoring techniques are applied to detect flaws during the build process with the aim to detect and repair defects right away during the manufacturing process. However, optical monitoring system require a clear view of the melt pool and quite expensive equipment. Acoustic monitoring by AE sensors attached to the built plate would be a cheaper alternative which also can be used without visual contact to the building chamber. This paper shows a first approach of an AE based process monitoring. The build plate of a PBF-LB/M machine therefore was adapted to hold four AE sensors that are then used to monitor the process. The build process itself creates AE signals caused by the melting and cooling and the mechanical application of powder. The formation of pores and cracks is expected to create additional acoustic emissions that will be distinct from the AE pattern from the printing process. This AE signals can be linked to the different layers of the printed part or in the long run to the laser position. Results from the first tests in a customized LPBF machine will be shown as well as the implementation of AE into the PBF-LB/M machine.
Method of Assessing the Level and Quantity of Sludge in Crude Oil Storage Tanks
Authors:   Office of Technical Inspection (UDT), Baran Ireneusz ,   AGH University of Science and Technology, Klimek Zbigniew ,   Office of Technical Inspection (UDT), Nowak Marek
Published: September 2024

When crude oil is stored in large tanks, invariably high-molecular-weight organic sediments (paraffin) are deposited but the resulting sediments contains also solid particles (sand, silt, corrosion products, etc.) and also water. After some period of in-service of tank, these deposits build up to form a sludge, which causes a reduction in the storage capacity. These high in hydrocarbons a valuable raw material could be proper recovered and recycled back to the refining process. Therefore, it is significant to know the sludge characteristics shape and volume to define the best form of treatment (maintenance of tank for control of level of sludge) and removal method (in case of out of service and opening of tank). The knowledge about volume and shape of such sludge inside tanks is important for user of tank farm due to a reasons such as e.g. maintenance of storage tanks and control of level of sludge inside them, when conventional treatments are used to remove crude oil sludge, there is a potential for high environmental impact, the choose of the method of cleaning is very essential. In this paper will be presented AE technique and thermography for assess of level, volume and shape of sludge inside storage tank. In 2017, the Office of Technical Inspection launched a project to develop a system for assessing the level and quantity of sludge in crude oil storage tanks, using the AE technique and thermography. As part of the project implementation, UDT started cooperation with companies, that are the leader in oil and fuel logistics in Poland. In the following years, a complete methodology and procedure for assessing the level, volume and shape of sediments was developed, as well as a process of verifying the results. A description of the invention was prepared and submitted to the Patent Office.
Monitoring a batch crystallization process by acoustic emission
Authors:   University of Lyon, De Souza Lima Roger ,   University of Lyon, Serris Eric ,   University of Lyon, Cameirao Ana
Published: September 2024

Crystallization is regarded as an important unit operation for separation and purification, as well as the production of solid particles with specified end-use properties. However, it is still difficult to control or to optimize the crystallization process due to the complexity of the coupled phenomena taking place simultaneously in the liquid and solid phases. In order to overcome such drawback, different analytical technologies have been implemented in the literature for monitoring (in situ, at best) the key crystallization parameters, e.g. solute concentration and crystal size distribution, which in turn enhances the comprehension about this operation. In our work, a multi-probe monitoring system composed of acoustic emission, ATR-FTIR and imaging probes was applied to the crystallization of a model system (an aqueous solution of adipic acid) in a semi-batch crystallizer. The crystallization was carried out under two different feed rates and under vacuum or atmospheric pressure. The goal was to demonstrate the usefulness of the multi-probe system for monitoring the crystallization process and to study the influence of the process (stirring rotation speed, cooling speed, etc.) on the acoustic emission. As a matter of fact, the multi-probe system tracked information about the dissolved adipic acid in the liquid phase with the ATR-FTIR spectrometry, while the crystal size, shape and number were monitored with the help of the imaging probe (with image treatment methods). The acoustic emission probes were used to detect the beginning of crystallization and the phenomena of crystal growth and agglomeration
Experience in Monitoring Brazed Aluminium Heat Exchanger, after Major Repairs
Authors:   PETROBRAS, Cruz Alessandro ,   PETROBRAS, Finkel Luiz ,   PETROBRAS, Bittencourt Carolina ,   Moura e Fiorito, De Moura Nestor ,   PETROBRAS, Nascimento Rafael ,   PETROBRAS, Da Silva Alisson ,   PETROBRAS, De Aquino João
Published: September 2024

Brazed Aluminium Heat Exchangers are fundamental for a natural gas liquid recovery plant. Refrigeration at cryogenic temperatures and the liquefaction process take advantages from their thermal hydraulic efficiency and compactness

characteristics, making such units economically feasible. These exchangers are proprietary design, with only a few manufacturers around the world and limited knowledge about their maintenance.

After two failures in the same equipment with possible thermal fatigue contributions, occurring only nine months apart, two complex repair procedures had to be carried out.

To ensure operational safety, online monitoring through Acoustic Emission Technique has been performed. This monitoring led to discoveries of systems and routine maneuverer that triggered damage mechanisms. This allowed for the implementation of adjustments to mitigate the propagation of damage, thereby increasing the equipment's lifespan.

The procedure applied in this type of equipment constitutes an innovative approach using the Acoustic Emission technique, which has resulted in a successful strategy of condition monitoring.
Two-Step AE Source location for Detecting Tendon Rupture inside PC Box-Girder in-Service
Authors:   Kyoto University, Okude Nobuhiro ,   Kyoto University, Asaue Hisafumi ,   West Nippon Expressway Company Limited (NEXCO-West), Fukuda Taiki ,   West Nippon Expressway Engineering Kansai Co., Ltd, Kawada Naoki ,   Kyoto University, Shiotani Tomoki
Published: September 2024

In order to identify tendon rupture inside a prestressed concrete (PC) girder, new acoustic emission (AE) location system is necessary to be practically applied. In PC girder of an in-service highway, PZT sensors are installed at a web and a deck of

the PC girder, and elastic waves generated by tendon rupture is simulated by steel ball impact. AE source location assuming the homogeneous velocity distribution is applied in a development view of the box-girder. Then to verify the accuracy of the location results, the effect of elastic-wave propagation at a joined corner between the web and the deck is simulated by FDM. As a result, the attenuation of first-arrival P waves was observed at the joined corner. It implies that wave energy is so attenuated that apparent velocity decreases. Finally, AE locations lead to erroneous solutions in the development view solved with a constant velocity. To solve the problem, a twostep location system is developed. In the first step, two-dimensional plane, where the tendon rupture is to be identified, is selected from the 1st and 2nd arrivals of AE Hits.

Then, in the 2nd step, AE locations are determined from remaining AE sensors located on this plane. By applying this system, the location errors are within 5 % at the both web and deck in a 15 m long PC box-girder.
Corrosion source location on a plate-like structure made of the Mg alloy WZ73
Authors:   TU Bergakademie Freiberg, Mandel Marcel ,   Polytec GmbH, Fritzsche Marco ,   TU Bergakademie Freiberg, Krüger Lutz
Published: September 2024

The new QTec Scanning Vibrometer is employed to analyze wave propagation resulting from corrosion. At a distance of d = 1.66 m, Lamb wave characteristics were recorded using an AE sensor and compared to a simulated corrosion event signal. The vibrometer's signal correlation enabled wave path reconstruction, ultimately facilitating the localization of the corrosion source by considering reflections and constructive interference effects in the AE sensor time signal.
Impact of Model Knowledge on Acoustic Emission Source Localization Accuracy
Authors:   Johannes Kepler University Linz (JKU), Erlinger Thomas ,   Johannes Kepler University Linz (JKU), Kralovec Christoph ,   Johannes Kepler University Linz (JKU), Humer Christoph ,   Johannes Kepler University Linz (JKU), Schagerl Martin
Published: September 2024

Reliable and precise damage localization in mechanical structures is of high importance in the context of structural health monitoring (SHM). The acoustic emission (AE) method has already shown its excellent suitability for damage localization. However, low signal-to-noise ratios (SNRs) are often prevalent in SHM, thus an increase in localization accuracy and robustness is still in demand. The present study faces this task through the integration of various model knowledge for AE

source localization. The basis of the presented algorithm is the consideration of the dispersive behavior of elastic waves in thin-walled structures. The continuous wavelet transform (CWT) is used to obtain time-frequency representations of the signals,

where frequency-dependent values for time-of-arrival (TOA) are extracted.

Furthermore, the algorithm incorporates the knowledge that all sensors receive signals with the same time and location of origin, as well as the slightly different sensitivity of the theoretically equal sensors. The final localization results are achieved by a two parameter grid search optimization. The algorithm is experimentally tested on a large aluminum plate with four piezoelectric wafer active sensors (PWASs) arranged in an array of 100 mm × 100 mm. The mean localization error of pencil lead breaks at ten different positions within the sensor array is used as an accuracy measure. It is shown that as more of the described model knowledge is incorporated into the localization, the accuracy increases. With the final algorithm, the mean localization error is more than halved compared to AE localization based on classical TOA estimation.

Although the experiment described is conducted under laboratory conditions, the remarkable increase in accuracy suggests that AE source localization may be successful even at low SNR as typical for operational conditions.
Optimising Sensor Placement for Tool Condition Monitoring: A Comparative Analysis of Acoustic Emission Data
Authors:   University of Augsburg, Baumeister Christina ,   University of Augsburg, Schlech Thomas ,   University of Augsburg, Luong Quy R. ,   University of Augsburg, Sasani Ehsan ,   University of Augsburg, Sause Markus G. R.
Published: September 2024

In the monitoring of machining processes and in the context of tool condition monitoring, the position of acoustic emission sensors affects the quality of the resulting information. This drives this comparative study which presents a comparison of acoustic emission data recorded simultaneously by a sensor attached to the side of the milling table and another sensor near the spindle during a tool wear test on a CNC milling machine. The signal information is clearly influenced by the different positions. Whereas the signals near the spindle are dominated by vibrations of the spindle motor during machining, these strong contributions do not occur in the recorded data of the machining process detected by the sensor mounted to the table.
However, the position of the sensor near the spindle has the advantage of maintaining a constant distance to the source of the acoustic emissions of the machining process, as the sensor moves with the tool. In contrast, the sensor attached to the milling table is affected from the fact that the distance to the milling tool is constantly changing.
This results in different dominant frequencies, that are analysed in this study. To
analyse both the entire frequency range and the higher frequencies, two distinct
approaches are employed, one without and one with the use of a high-pass filter.
Furthermore, the recorded signals were used to calculate the characteristic features,
namely the Partial Powers, thereby enabling assessment of the condition of the tool. The results demonstrate that this single feature type is sufficient for training a machine learning model to predict the tool wear, focusing on the flank wear width. This study analyses the efficiency of wear prediction with respect to both sensors and frequency spectra, and compares the results. In this context, the most accurate predictions were achieved with Gaussian process regression models.
The Influence of Coupling-Specific Parameters and Structural Parameters on the Electromechanical Impedance of Acoustic Emission Sensors
Authors:   Bochum University of Applied Sciences (BO), Reinhardt Christopher ,   Bochum University of Applied Sciences (BO), Priebe Sebastian ,   Bochum University of Applied Sciences (BO), Mueller Inka
Published: September 2024

Acoustic emission (AE) sensors are widely used for testing and monitoring purposes, necessitating effective field-testing methods to assess their functionality during use, ideally resulting in a method for self-diagnostic. A novel approach for field-testing is to measure the electromechanical impedance (EMI) of the AE sensor. This method requires minimal additional equipment and eliminates human interaction, which is needed for current field-tests like pencil-lead break tests. However, the EMI includes the mechanical impedances of the sensor, the coupling layer, and the structure. Therefore, the measurements contain information about all three and influences of the structure and the coupling layer need to be investigated to be able to establish a method for self-diagnosis in field. Additionally, the piezoelectric effect is temperature-dependent, which affects the measured EMI spectra and may result in erroneous assessments of the sensor's condition if not accounted for.

This work presents experimental studies on the influence of measuring equipment, environmental temperature, coupling-specific parameters and structural parameters on the EMI of AE sensors. Moreover, numerical simulations have been conducted to provide additional support and to extend the experimental studies of the latter two. To ensure reproducible sensor coupling to a structure, a setup was constructed to couple the sensor to the structure at the same position and with the same force. The thickness of the coupling layer is determined by a small amount of silicon carbide particles with a specific diameter. This setup is also used to examine the effect of structural parameters.
Assurance of Iintegrity of Composite Pressure Vessels by AE Testing Using Remaining Life Indicator
Authors:   Tokyo Institute of Technology, Samejima Masaaki ,   Tokyo Institute of Technology, Nakamura Shunsuke ,   Tokyo Institute of Technology, Mizutani Yoshihiro
Published: September 2024

Composite overpressure vessels (COPVs) are utilized in fuel cell vehicles (FCVs). The remaining life of COPVs decreases with repeated fillings. To indicate this decrease in remaining life, a remaining life indicator is embedded in the vessels.

When the remaining life decreases, the indicator fractures before the structural components do. This allows for early detection, signalling the critical life of the vessel.

Specifically, the indicator is designed to fracture before the carbon fiber, ensuring the vessel's strength. This fracture is then detected by AE (Acoustic Emission) testing, enabling us to determine the vessel's remaining life. In this study, we embedded the indicator in coupon specimens and conducted a preliminary study to assess the feasibility of our proposed method. As the indicator, we used a carbon fiber with a

slightly smaller fracture stress compared to the carbon fiber comprising the vessels.

Three types of coupon specimens with different amounts of indicator were prepared, and tensile tests were conducted. As a result, the fracture stress was not affected by the incorporation of the indicator, and the indicator's failure did not induce the fracture of the original CFRP (Carbon Fiber Reinforced Plastic). These results indicate that the integrity of COPVs can be ensured by incorporating the indicator and monitoring

the fracture of these materials using AE testing.