bluuebunny/crossref_metadata_2025 huggingface dataset:
Altruism and tax compliance: Unveiling the dual role of charitable giving and social norms in global tax evasion
Authors: Ramadhan Muhammad Rheza , Widiarto Fajar , Liriyansah Bismar , Khusaini Fachrul , Arifandi Budi
Published: January 2025

This study investigates the relationship between altruistic behaviors and tax evasion, using panel data from 172 countries spanning 2011 to 2020. The analysis focuses on three dimensions of altruism—helping strangers, volunteering, and donating to charity—derived from the World Giving Index, while tax evasion is proxied by the size of the informal economy as estimated by the IMF. With a final sample of 1,103 country-year observations, the study employs a fixed effects regression model to account for unobserved, time-invariant heterogeneity across countries and global shocks over time. GDP per capita, sourced from the World Bank, is included as a control variable. The findings reveal a dual relationship: the percentage of individuals helping strangers is negatively correlated with tax evasion, suggesting that strong social norms and intrinsic motivations for altruistic behavior promote tax compliance. In contrast, the percentage of individuals donating to charity is positively correlated with tax evasion, indicating that charitable giving may sometimes rationalize non-compliance through mechanisms like the Crowding-Out Hypothesis or the Compensatory Altruism Hypothesis. Volunteering, however, shows no significant effect on tax evasion. These results underscore the complexity of the relationship between pro-social behaviors and tax compliance. Policymakers are encouraged to promote social norms that foster both altruism and tax compliance while carefully designing tax incentives for charitable giving to prevent unintended consequences. This study contributes to the literature by providing nuanced insights into the interplay between altruistic behaviors and tax evasion on a global scale, highlighting the importance of context in understanding compliance behaviors.
Automated Timetable Generation With Real-Time Updates
Authors:   Dept. of Computer Science and Engg.  Malnad College of Engineering Hassan, India, Uma B
Published: January 2025

This paper presents an automatic generation of a real-time timetabling system, which overcomes the limitations of traditional systems by avoiding traditional conflicts, in efficiency, and inflexibility. The constraints used in optimizing the genera- tion process are advanced: multiple constraints handling, includ- ing availability of teachers, classroom availability, balance in the scheduling, and conflicts. The current system incorporates some innovations, such as the capability to update real-time changes, thus making it easier to handle dynamic changes - for instance, swapping classes between teachers, reports of teacher absence, and special adjustment requests. These updates are instantly synchronized across all devices with minimal disruption to ensure flexibility in day-to-day academic operations. It is built for high scalability and efficiency, with the use of Firebase for real-time data updates, Flutter for a responsive and user-friendly cross- platform experience, and Docker to support scalable and reliable deployments. Moreover, the platform supports enhanced admin- istrative control, real-time notifications, and detailed analytics for improved decision-making. This significantly improves the efficiency, accuracy, and adaptability of the scheduling process as the system has automation in the scheduling process that reduces manual effort, minimizes errors, and provides greater flexibility compared to the traditional static timetables. This paper is based on a detailed design of the system with a technological basis, providing rich benefits to the administrators, faculty, and students.
SO SÁNH GIÁ TRỊ GIỮA CẮT LỚP VI TÍNH VÀ CỘNG HƯỞNG TỪ TRONG ĐÁNH GIÁ LẠI GIAI ĐOẠN T CỦA UNG THƯ BIỂU MÔ TRỰC TRÀNG SAU ĐIỀU TRỊ TÂN HỖ TRỢ
Authors: Ngô Quang Hưng , Trần Minh Hoàng , Võ Tấn Đức , Lâm Thanh Ngọc
Published: January 2025

Giới thiệu: Đánh giá giai đoạn đóng vai trò quan trọng để lựa chọn phương thức điều trị tối ưu cho người bệnh ung thư biểu mô trực tràng (UTTT). Đặc biệt đối với trường hợp sau hóa xạ tân hỗ trợ (HXTHT), việc này ảnh hưởng đến phương pháp phẫu thuật, ví dụ cắt trọn tại chỗ hay toàn bộ trực tràng.
Mục tiêu: So sánh giá trị của cắt lớp vi tính (CLVT) và cộng hưởng từ (CHT) trong việc đánh giá giai đoạn u tại chỗ (yT), tình trạng di căn hạch vùng và diện cắt chu vi (yCRM) sau hóa xạ tân hỗ trợ (HXTHT).
Đối tượng và phương pháp nghiên cứu: Nghiên cứu mô tả cắt ngang trên 62 bệnh nhân UTTT được chụp CLVT và CHT trước và sau HXTHT với liệu trình dài, có phẫu thuật và kết quả giải phẫu bệnh (GPB) tại Bệnh viện Đại học Y Dược thành phố Hồ Chí Minh. Giai đoạn bệnh được đánh giá lại trước phẫu thuật trên CLVT và CHT, đối chiếu với kết quả GPB có mô tả đầy đủ giai đoạn ypT, di căn hạch, ypCRM.
Kết quả: Giá trị của CLVT và CHT đánh giá giai đoạn khác T0 là không khác biệt. Cả hai phương tiện chẩn đoán đều có độ nhạy, giá trị tiên đoán dương và độ chính xác cao trong đánh giá giai đoạn khác T0. CLVT và CHT đều có độ đặc hiệu, độ chính xác và giá trị tiên đoán âm cao trong đánh giá giai đoạn T4 (82 – 94,5%). Về độ chính xác chung, CLVT thấp hơn CHT trong đánh giá giai đoạn T (38,7 so với 54,8%). Trong đánh giá có hay không hạch di căn, CLVT và CHT không có sự khác biệt rõ về giá trị. Cả hai đều có giá trị tiên đoán âm khá tốt, xấp xỉ 80%. CLVT và CHT đều có giá trị tiên đoán âm cao trong đánh giá xâm lấn cân mạc treo trực tràng, xấp xỉ 95%. CHT có độ đặc hiệu, độ chính xác cao hơn CLVT từ 11-13%.
Kết luận: Sau điều trị tân hỗ trợ, CLVT và CHT đều cho độ tin cậy tốt trong phát hiện mô u còn lại, do đó có thể cân nhắc chiến lược “theo dõi và chờ” đối với những trường hợp không còn thấy u. Cả hai đều cho độ tin cậy tốt để loại trừ giai đoạn yT4, di căn hạch vùng và xâm lấn cân mạc treo trực tràng (CMTTT).
ĐÁNH GIÁ MỐI LIÊN QUAN GIỮA GIÁ TRỊ TIÊN LƯỢNG CỦA PET/CT VÀ ĐÁP ỨNG SAU HOÁ XẠ TRỊ ĐỒNG THỜI Ở NHÂN UNG THƯ THỰC QUẢN GIAI ĐOẠN III KHÔNG PHẪU THUẬT ĐƯỢC
Authors: Mai Thị Quỳnh , Phạm Lâm Sơn , Trần Thế Hoàng , Châu Quỳnh Anh , Nguyễn Quang Toàn
Published: January 2025

Mục đích : Đánh giá mối liên quan giữa giá trị tiên lượng của PET/CT và đáp ứng sau hoá xạ trị đồng thời ở bệnh nhân ung thư thực quản giai đoạn III không phẫu thuật được.
Đối tượng và phương pháp: Nghiên cứu (NC) mô tả hồi cứu và tiến cứu 48 Bệnh nhân ung thư thực quản biểu mô vảy giai đoạn III (T1,2N2M0 hoặc T3,N1,2,M0) bệnh nhân được chụp PET/CT tính toán các giá trị (SUVmax,MTV,TLG) của tổn thương u thực quản, sau đó được  điều trị hoá xạ trị đồng thời tại bệnh viện K thời gian từ tháng 1/2023 đến tháng 6/2024. Theo dõi dọc qúa trình điều trị và sau điều trị tìm mối liên quan giữa giá trị PET/CT và tiên lượng dựa vào thời gian sống thêm không bệnh (PFS) và toàn bộ (OS).
Kết quả: Nhóm NC 100% nam giới, tuổi trung bình 61,25± 6,67 tuổi. Tiền sử hút thuốc và lạm dụng rượu bia 81,25 %. Vị trí tổn thương hay gặp 1/3 giữa (45,8%), hai đoạn thực quản (22,9%), ít gặp ở đoạn 1/3 trên (10,4%). Giai đoạn trước điều trị T1,2N2 (43,8%) và T3,N1,2 (56,3%). Phân tích đường cong ROC cho các thông số PET/CT nhóm NC liên quan đến giai đoạn cT3 tương ứng SUVmax > 18,5 g/mL (độ nhạy 51,9%, độ đặc hiệu 76,2%, p < 0.01), TLG > 181,5 g (độ nhạy 70 %, độ đặc hiệu 95,6%, p < 0.001), MTV > 25,5 cm3 (độ nhạy 66,7%, độ đặc hiệu 99 %, p < 0.001). Bệnh nhân điều trị hoá xạ trị đồng thời với xạ trị liều £ 50.4 (83,3%), hoá chất: FOLFOX (56.3%), XELOX (35,4%) và CF (8%). Thời gian theo dõi trung bình nhóm NC là 9,6 tháng (khoảng 3,02-18,2). Sau điều trị, 36 bệnh nhân (75%) bệnh còn tiến triển. Thời gian sống thêm không bệnh (PFS) sau 12 tháng có sự khác biệt của nhóm cT1,2 và cT3 tương ứng là 33,4% và 22,2% (p<0,05). SUVmax < 18,5 g/mL, MTV < 25.5  cm3 và TLG <181,5 g có tiên lượng tiên lượng tốt với PFS (tương ứng p<0,05, p<0,001 và p<0,01). Tuy nhiên, không có sự khác biệt các chỉ số SUVmax,MTV,TLG với thời gian sống thêm toàn bộ của nhóm NC.
Kết luận: Giai đoạn T và các thông số u thực quản trên PET/CT có ý nghĩa dự báo tiên lượng đánh giá đáp ứng sau hoá xạ trị đồng thời ở bệnh nhân ung thư thực quản biểu mô vảy giai đoạn III không phẫu thuật được.
NGHIÊN CỨU ĐÔNG KHÔ BEVACIZUMAB VÀ ĐÁNH DẤU VỚI Tc-99m ĐỂ CHỤP HÌNH MIỄN DỊCH PHÓNG XẠ UNG THƯ
Authors: Thi Thu Nguyen , Nguyen Thi Khanh Giang , Nguyễn Thị Ngọc , Nguyen Thanh Binh , Đặng Hồ Hồng Quang , Nguyễn Thanh Nhan , Phạm Thành Minh
Published: January 2025

Tóm tắt: Mục tiêu: Bevacizumab, kháng thể đơn dòng nhân hoá kháng VEGF, được nghiên cứu đông khô và đánh dấu với 99mTc để tạo thành 99mTc-bevacizumab dùng trong chụp hình khối ung thư. Mục đích của nghiên cứu là phát triển công thức và quy trình đông khô thuốc bevacizumab. Phương pháp: Bevacizumab được khảo sát đông khô theo hàm lượng các chất, pH, nhiệt độ và thời gian. Hợp chất đông khô được kiểm tra tính ổn định, đánh dấu với đồng vị phóng xạ 99mTc, kiểm tra độ tinh khiết hoá phóng xạ và độ bền. Kết quả: Kết quả nghiên cứu cho thấy, bevacizumab được đông khô tạo thành dạng khô xốp, màu trắng, ở các điều kiện tối ưu như đệm phosphat 0,5 M, pH 7,4 ở nhiệt độ    -40 ℃ và thời gian 24 giờ. Bevacizumab đông khô ổn định sau 6 tháng theo dõi. Độ tinh khiết hóa phóng xạ của 99mTc-bevacizumab đạt hơn 98 %, đạt vô khuẩn và nội độc tố vi khuẩn. Kết luận: Bevacizumab đã được điều chế dạng đông khô, có thể dùng để đánh dấu với 99mTc, đạt các chỉ tiêu về thuốc phóng xạ và có thể dùng trong các nghiên cứu tiền lâm sàng.
Consignment accounting - a tool of mitigating loss of cargo in shipping industry
Authors: Othman Mahdy S.
Published: January 2025

This research aims to find out whether consignment accounting is an effective weapon in combating high rates of cargo loss in the shipping sector. The study’s objectives are to evaluate the extent of consignment accounting in managing the probability of cargo loss for countries like Jordan, Norway, Greece, Denmark, and the Middle East. Six hundred respondents were included in the study and data was recorded on the frequency and severity of cargo loss in addition to respondent satisfaction before and after the use of consignment accounting. The data was analyzed using descriptive statistics, paired sample t-tests, ANOVA, Pearson’s correlation, and multiple regression analysis. There are three significant findings that we observed: CONSA group results indicated that consignment accounting implemented decrease the cargo loss percentage throughout all the regional locations we studied; nevertheless, Norway and Denmark show the identical is leading overall, meaning this new accounting technique has an extraordinary performance in avoiding cargoes from being lost. The study found a positive significant relationship between the intensity of consignment accounting adoption and decrease in cargo loss. Simvely, the study finds that the accounting consignment is a useful approach to reducing loss in cargo, particularly in areas that experience more frequent losses. Furthermore, high levels of adoption are related to high satisfaction levels and thus the increased use of the system is advantageous to the shipping industry.
Enhancing Quality of Teacher Services through Strengthening Knowledge Management, Interpersonal Communication, Organizational Support and Job Satisfaction
Authors: Hermawan Andi
Published: January 2025

Customer perceptions regarding the comparison between fulfilling needs and desires and the accuracy of delivery to balance customer expectations which are closely related to the quality of products, services and human resources are called Service Quality. Teachers are the main aspect and key determinant of successful learning, policy implementation and creative, innovative efforts, as well as the democratization of education. Teachers are the main players and spearheads in the world of education. Therefore, the existence of programs that concretely always support, accompany and help to continue to develop the personal and professional qualities of teachers is a guarantee for brilliant education. Based on preliminary research, it is known that the permanent foundation teachers (GTY) of PGRI Vocational High Schools (SMK) in Bogor Regency have relatively suboptimal service quality. Therefore, research is needed to obtain information on variables related to improving service quality. The aim of this research is to make efforts to improve the quality of service for vocational school teachers by conducting research on the influence of the variables knowledge management, interpersonal communication, organizational support and job satisfaction. This research uses the path analysis method to determine the influence between the variables studied and the SITOREM method for indicator analysis in order to obtain optimal solutions in an effort to improve the quality of vocational school teacher services.
Role of Banks on Economic Development: A Special Reference to Management of NPA in Public and Private Sector Banks
Authors: M Chandramma.
Published: January 2025

Non-performing assets are advances e been past due over more than 90 days in terms of interest and/or principal payments. A substandard asset remains non-performing for a period of less than or equal to 12 months. An asset is as doubtful if it has been in the substandard category for 12 months. A loss asset is one in which the bank has identified a loss or external auditors, or an RBI inspection but the amount has not been fully written off. The study focused mainly on the comparison of NPAs and Bank performance across public and private sector banks, To discuss trends in bank performance concerning public sector and private sector banks- descriptive statistics comparison. To analyse trends of NPA in public sector bank and private sector bank- Descriptive Statistics Comparison. The study focused on scope, significance, and methodology. The study regarded Axis Bank as a public sector bank representative and Bank of Baroda as a private sector bank. Correlation analysis is a statistical technique used to determine the direction and strength of a relationship between two variables. Correlation analysis can be used to assess the relationship between nonperforming assets (NPAs) and key economic metrics such as financial stability, credit growth, and profitability. The study can find differences in how public and private sector banks affect economic development by comparing correlation patterns between them. The basis for focused policy interventions is this analysis, which offers insightful information about how NPAs and more general economic factors are interconnected. Finally, the study analyzed the data and interpreted the results. Suggestions also discussed in the study.
Developing listening skills for high school students through songs: An empirical study
Authors: N H Thang , N H The , T T Du
Published: January 2025

The current study concentrates on listening, one of the four basic language skills. According to the Common European Framework of Reference for Languages, listening is frequently overlooked, and students almost tend to struggle to learn through it. This study’s objective is to evaluate the effects of songs on students’ listening skills and motivation. The participants included two groups of 11th grade students from a high school in Binh Duong province of Viet Nam, who learned English as a foreign language. Questionnaires and interviews were utilized to acquire both quantitative and qualitative data. A pre-test and a post-test were also prepared to assess both how far the students progressed after implementing the study project and their motivation in learning English through songs. At the end of the treatment, the average post-test score was greater than the pre-test score within experimental group. Research results indicate that music and songs may not only be entertaining, but also give students several benefits, a specially in developing their listening skills. Students’ motivation in their language learning in general and in learning listening skills also increased considerably.
Reading Comprehension Module and Students’ Achievement in Literature
Authors: Fernando Love Lita J. , Ambayon Cristobal M.
Published: January 2025

This experimental study aimed to find out the extent of acceptability of the Reading Comprehension Module in terms of the content, relevance, mechanics, instructional aspect, acceptability, usability, design and layout, readability and reliability as a learning tool to enhance and improved the reading ability of Grade 7 students who belong to frustration level at Lambayong National High School for the School Year 2021-2022. The findings of the study revealed that the Reading Comprehension Module was excellent based on its acceptability and has passed the qualities expected by the teachers to students and where it cater their needs that could enhance as well their learning skills and abilities. With the design and content of the module, it unveil that it is consonance to the level of abilities of the respondents. Furthermore, it can be concluded based on the results determined of this research, the use of the Reading Comprehension Module in Teaching Philippine Literature is effective as most of the objectives have been met. Hence, it was recommended for further research the use of Reading Comprehension Module in Teaching Philippine Literature and develop a reading module based on the literature of the different tribes in the locality.
The Cold War Resurgence: A Discourse on the Rivalry between ECOWAS and AES in West Africa
Authors: Adisa Oluyemi, Opeoluwa
Published: January 2025

The Cold War, a descriptive of 45year (1945-1990) of ideological rivalry between the United States and Soviet Union, as well as their competing coalitions, which sought to contain each other‘s expansion and gain worldwide predominance has constituted one of the most notable events and a discourse topic in International Relations. Scholars have indicated the emergence of economic interdependence of states, the increasing need of societal security, environmental security, human security, the rise of capitalism and the role of non-states actors expounded within the various strands of liberal theory to have marked the end of realist/military construct of world politics that gained prominence during the Cold War. However, this research argues on the possible continuation of the old Cold War in the present contemporary era using the recent unfolding rivalry within the West African region as a case study. Recently, the Sahel region in West Africa has been confronted with political instability and security challenges, marked by the rise of insurgent movements, military coups and deteriorating state governance. The Alliance of Sahel States (AES) was created in September 2023 by the three military juntas of Mali, Niger and Burkina Faso as a counterweight to ECOWAS and the postcolonial influence of France and other Western allies. With the adoption of qualitative research method, depending mainly on secondary sources, this research examines the possibility of the Cold War resurgence between the two opposing blocs in West Africa (ECOWAS and AES), the prospect of the region becoming a proxy battleground through the involvements of opposing international allies (western and anti-western allies).
Dental Education in the Interior of a Brazilian State: Profile of Patients and Procedures Performed in a Teaching Clinic
Authors: Silveira Glauco H. T. da , Maciel Alexandre B. D. , Cruz Tímilly M. M. da , Gusmão Yure G. , Glória José C. R. , Lages Frederico S. , Douglas-de-Oliveira Dhelfeson W.
Published: January 2025

Objective: This study aimed to identify the profile of adult patients treated at the Integrated Clinic of the UFVJM Dentistry course in Diamantina-MG between 2010 and 2019. Methods: A retrospective analysis was conducted using patient records from individuals who had completed treatment and were discharged. Only fully completed and legible records were included, while those that were incomplete, illegible, or related to ongoing treatments were excluded. Data collected encompassed gender, age, place of origin, race, comorbidities (such as diabetes and hypertension), treatment duration, start and end year of treatment, smoking habits, alcohol consumption, and the types of procedures performed, categorized into various treatment groups. Results: Out of 469 records analyzed, 414 met the inclusion criteria. The majority of patients were female (63.5%), predominantly of mixed race (46.3%), with an average age of 34.1 years, and most resided in Diamantina (84.7%). The highest number of treatment initiations occurred in 2018 (41.6%), which also had the most discharges (38.4%). The average treatment duration was 66.3 days. Radiography was the most frequently performed procedure (22.3%), while endodontic treatment was the least common (2%). A positive correlation was identified between age and the creation of removable prostheses. Conclusion: The predominant profile of patients treated at the clinic consists of young, mixed-race women, primarily residents of Diamantina, who tend not to smoke but frequently consume alcohol. These findings provide insights into the demographic and treatment needs of the population served by the clinic, informing potential improvements in patient care and educational approaches in the dentistry program.
Scientometric Analysis of Personalized Learning Research
Authors: Jantakun Thiti , Jantakun Kitsadaporn , Jantakoon Thada
Published: January 2025

This study presents a scientometric analysis of personalized learning research from 2020 to 2024. Using the Lens database, 4,463 scholarly articles were analyzed to identify key trends and patterns in this rapidly evolving field. The analysis revealed consistent publication growth over the 5 years, with journal articles dominating as the primary publication type. Hessian Normal University emerged as the most productive institution, while Jackson Steinher was identified as the most prolific author. The United States and China were the leading countries in terms of research output. Education and Information Technologies was the top journal publishing personalized learning research. Co-authorship network analysis highlighted collaborative patterns among researchers, while keyword co-occurrence networks revealed the centrality of artificial intelligence and related concepts in the field. Citation analysis identified influential documents and sources shaping the discourse. The findings suggest an increasing focus on integrating AI and machine learning into personalized learning systems and a growing emphasis on interdisciplinary approaches. This scientometric overview provides valuable insights into the current state and emerging trends in personalized learning research, which may inform future studies and applications in this domain.
ENHANCING THE QUALITY OF EMERGENCY ADMISSION CLERKING IN NEUROSURGERY: A COMPARATIVE STUDY OF TRADITIONAL METHODS VERSUS A SURGICAL CLERKING PROFORMA
Authors: Kazmi Waseem , Ushna Khan Durrani  , Zara Rathod  , Aya Abdelhamid Elshalakany
Published: January 2025

Background: Accurate and comprehensive documentation during emergency admissions is crucial for ensuring patient safety. This is especially important in high-risk environments such as neurosurgery. Traditional freehand clerking methods often result in incomplete or inconsistent records, potentially compromising patient care. This study aimed to evaluate the impact of introducing a structured surgical clerking proforma on the quality of emergency admission clerking in a tertiary care neurosurgery unit. Methods: A three-phase comparative audit was conducted, comprising an initial audit of traditional clerking methods (Cycle 1), the implementation of a surgical clerking proforma, and a subsequent re-audit using the proforma (Cycle 2). Data were collected retrospectively from 40 patient records in Cycle 1 and prospectively from 30 patient records in Cycle 2. The completeness of documentation was assessed across 31 key parameters, and statistical significance was determined using paired t-tests on simulated data. Results: The introduction of the surgical clerking proforma resulted in significant improvements in documentation completeness, particularly for parameters such as the Consultant Responsible and Reviewing Doctor, which saw increases of 30% and 32.5%, respectively (p<0.05). These improvements underscore the effectiveness of the proforma in standardizing and enhancing the reliability of clinical documentation. Conclusion: The structured surgical clerking proforma significantly improved the quality of emergency admission documentation in the neurosurgery unit. The findings support the broader adoption of such proformas across various medical specialties to enhance the accuracy, consistency, and reliability of clinical records, ultimately contributing to improved patient care and safety.
Long short-term memory neural networks applied in demand forecast in the retail market
Authors: Fernanda Mayumi Fukai  , Daniel Cruz Cavalieri  , Fidelis Zanetti de Castro
Published: January 2025

Sales forecasting is an indispensable component of the retail industry, underpinning strategic decision-making and operational planning, and is crucial for maintaining financial stability and facilitating business growth. While traditional statistical methods have been widely utilized to address issues in time series analysis, they often fall short when confronted with high-dimensional, complex, or dynamic non-linear relationships between variables.In this context, Long Short-Term Memory (LSTM) networks offer significant advantages due to their capability to retain information over prolonged periods. These qualities make LSTMs particularly suited for handling scenarios characterized by complexity and dynamic interactions within the data.This study evaluates the efficacy of three distinct LSTM architecturesVanilla LSTM, ConvLSTM, and CNN-LSTM Multiscalein forecasting future sales. For a comprehensive analysis, an Average model is also employed as a baseline for comparison. The performance of these models is assessed using several metrics, including Mean Average Error (MAE), Root Mean Squared Error (RMSE), and Mean Absolute Scaled Error (MASE). This comparative analysis aims to elucidate the relative strengths of each LSTM model in the realm of time series forecasting.The findings suggest that the ConvLSTM architecture generally surpasses the other models across most evaluation metrics. Furthermore, this study concludes that LSTM-based models are adept at navigating the complexities inherent in time series data, identifying intricate patterns over extended durations. This capability is important for effective forecasting in various practical, real-world scenarios, reinforcing the utility of LSTM networks in advanced analytical applications in the retail sector.
Virtual Element Method: An overview of formulations
Authors: Tiago Fernandes Moherdaui  , Alfredo Gay Neto
Published: January 2025

The virtual element method has been around for about a decade, and it has been through a lot of development during this period. The method generalizes the finite element method for polytopal elements, while retaining optimal convergence properties. This is achieved mainly by implicitly defined function spaces and the use of polynomial projections. This work presents an overview of the development of the method as formulated for elliptic problems in two and three dimensions, here represented by Poissons equations. The formulations covered are: its original formulation, the modified formulation enabling three-dimensional elements, the Serendipity formulation, and one of the formulations for self-stabilized elements.
A Surrogate-Based Approach for Bend-Twist Coupling Optimization of a Horizontal Axis Wind Turbine Composite Blade
Authors: Tiago Felipe Gaiguer Farias  , Claudio Tavares da Silva  , Marco Antonio Luersen
Published: January 2025

A design study on the effect of bend-twist coupling in a composite blade of horizontal axis wind turbine (HAWT) is conducted. Using specific lamination sequences with unidirectional plies, a laminated composite is obtained whose mechanical stresses are coupled in its bending and twisting. Given the aerodynamic forces on the blade during its operation, mechanical stresses emerge in the material, which, due to its bend-twist coupled behavior, conforms elastically, adapting its geometry to the wind flow. The tailoring of aeroelastic effects can be applied to wind turbine blades to improve the performance of wind turbines. Furthermore, the manufacturing costs, either from material or process perspectives, are potentially reduced with well-designed layup sequences. A blade is first designed according to specific parameters using the Blade Element Momentum Theory (BEMT) under the assumption of total rigidity. These include operational and constructive parameters (e.g., desired output power, airfoil profile characteristics, nominal wind velocity, number of blades, etc.). The effect of bend-twist coupling in the laminated composite is analyzed by fluid-structure interaction (FSI). The layup sequence is parametrized within ANSYS Composites PrepPost (ACP) with different laminations for upper and lower face of the blade, given both geometry and stress distributions differ for each face. The CFD and the structural behavior are coupled in a two-way FSI system, along with material properties evaluated from ACP. Thus, deformations are computed using the pressure distribution from CFD and material properties from ACP. The power coefficient is calculated once the FSI simulation has converged, yielding the resultant torque and rotation, which are then used to evaluate the extracted power.. An optimization routine is implemented to maximize the power extraction as a function of the lamination sequence for the upper and lower faces of the blade. The computational cost of the optimization procedure is reduced by employing radial basis function neural network, acting as a surrogate model. It is predicted an increase of up to 10% in the power coefficient for the generator. The final proposed laminated composite for upper and lower faces of the blade extends the power curve of the generator, allowing it to sustain operation even in overload conditions, delaying stall of the blades and avoiding tower collapse by excessive blade tip axial deflection.
Cost Optimization of RC Beams Considering Steel Rebar Losses
Authors: Moacir Kripka  , Igor Fernando dos Santos Lira  , ÍkaroThyerri Afro Borges
Published: January 2025

Optimization techniques are an efficient tool for developing structural projects. By seeking the rational use of available resources, they can not only reduce costs but also the impact on the environment. In this sense, it is interesting that these techniques are effectively incorporated throughout the process, including at the construction stage. For example, in the design of reinforced concrete structures, an additional 10 percent of steel consumption is usually foreseen due to losses from cutting rebar, which is supplied in standard lengths on the market. These losses can be significantly reduced if the bars are cut according to an optimized plan. This study aims to combine the optimization of the cost of reinforced concrete beams with the minimization of losses due to the cutting of steel bars. Initially, the two optimization problems were implemented separately and used sequentially, using the Harmony Search Optimization Method. Several simulations were then carried out to assess the influence of factors such as the number of beams and the number of gauges on losses and final costs. In a second stage, the aim is to integrate the two problems so that the reduction of losses can be optimized even during the design and detailing phase of the structure.
Integrating metaheuristic and machine learning for optimization of a full-scale transmission line tower
Authors: Gabriel Padilha Alves  , Leandro Fleck Fadel Miguel  , Rafael Holdorf Lopez
Published: January 2025

In long transmission lines (TLs), the design of a transmission line tower (TLT) can be replicated multiple times, a contrast to most structures that feature a unique design. Various optimization methods have been developed to reduce the overall mass of these structures. Historically, most research has relied on metaheuristic algorithms to identify optimal solutions. More recently, machine learning (ML) techniques have begun to be integrated with metaheuristics to speed up the optimization process, although ML has primarily been applied to smaller TLTs, in academic settings, or to simplify structural analysis, potentially compromising accuracy. This paper introduces a new approach that combines the Backtracking Search Algorithm (BSA), known for its efficacy in similar real-world TLT optimization challenges, with Kriging-based Efficient Global Optimization (EGO). This methodology starts by optimizing the size using BSA and subsequently employs EGO to refine the shape. This dual-step optimization effectively significantly reduces the mass of the TLT with only a few hundred additional objective function evaluations (OFEs). In comparison, simultaneous size and shape optimization using BSA alone requires over one hundred thousand additional OFEs to achieve comparable results, showing the potential of the proposed approach in dealing with expensive engineering design optimization problems.
Modified genetic algorithm for efficient optimization: application to prestressed concrete structural elements
Authors: Sinara de Aquino Sousa  , Antônio Macário Cartaxo de Melo  , Elias Saraiva Barroso
Published: January 2025

Prestressing, whether bonded or non-bonded, has become increasingly attractive as it allows for larger spans, greater architectural flexibility, greater agility in execution and greater durability. All of these advantages are capable of making prestressed concrete structures more economical solutions when associated with an efficient scaffolding system and formwork. The use of prestressed beams combined with ribbed slabs allows the slabs and beams to have the same height, thus favoring the architecture, in addition to facilitating the assembly of formwork and concreting. The designer can appropriately define the dimensions of the beams and slabs, as well as parameters such as the quantity and layout of cables by trial based on experience. However, the use of numerical optimization techniques are tools recognized as appropriate for the search for a structural solution, where design parameters, whether at the level of design (topology), intermediate (shape) or detail (dimension), can be determined such that the solution minimizes a performance measure, for example, cost, which takes into account the cost of materials, the volume of concrete, the weight of passive and active reinforcement, and labor productivity. Given the discrete nature of some variables, genetic algorithms (GA) have been widely used. GAs have control parameters and operators that are, in general, dependent on the problem, requiring calibrations in each case. The objective of this work is to review some optimization models and improve the GA of the BIOS program - developed at the (Computational Mechanics and Visualization Laboratory) LMCV of the Federal University of Ceará (UFC) - investigating new operators, thus aiming at the efficiency of the algorithm for prestressed elements, using a prestressed band beam as a case study. Genetic operators, in particular crossover, will be targets of the study.
Expansion of an Object-Oriented Framework to Consider Reddy Model for Reticulated Structures
Authors: Marcos Antonio Campos Rodrigues  , Rodrigo Bird Burgos  , Rafael Lopez Rangel  , Eugenio Ruocco  , Luiz Fernando Martha
Published: January 2025

Classical softwares to perform structural analysis using the Finite Element Method (FEM) considers the Euler-Bernoulli and Timoshenko beams theories. However, these theories may not provide stress results with sufficient accuracy. Therefore, this study presents the expansion of an open-source object-oriented framework for structural analysis of frame structural models considering the Reddy beam model. Also, is presented a 3D Reddy formulation to perform linear and nonlinear geometric analysis. The computational implementation evidence the importance of use object-oriented frameworks, and open-source codes. The developed examples clearly shows the improvements in the shear stress prediction when considering higher order beams formulations in a frame element, and clarify for graduate and undergraduate students the diferences between the most usual beams formulations.
Geometric nonlinear analysis of soil-structure interaction with trusses using positional formulation
Authors: Thiago Rodrigues Carvalho  , Rodolfo André Kuche Sanches  , Humberto Breves Coda
Published: January 2025

Although in many situations it is possible to consider civil structures as supported on immovable foundations, in situations of moderate settlement it is necessary to consider the interaction between the soil and the structure, considering both flexible. Soil deformability can cause considerable changes in support reactions and stresses, which are fundamental for structural design. In turn, this change in the loads transmitted to the soil causes the deformations presented by the soil to change. Thus, this work deals with coupling a formulation for nonlinear analysis of spatial trusses with a solution to the problem of settlements in stratified soils. The truss analysis follows the positional formulation of the finite element method (FEM), as presented in Coda (2018), while the soil domain analysis is based on fundamental cases of elasticity theory, as presented in Pinto (2006), Mundim, Cruvinel and Cavalcanti (2014), and in Poulos and Davis (1980), considering the characteristics of the soil based on geotechnical field tests. The calculation of soil deformation considers both the influence of direct loads on the support considered and the indirect effects of tensions due to adjacent supports, considering the variation in tension spatially, that is, along the depth of the soil below the foundation and of the adjacent region. The computational code for dynamic analysis of three-dimensional trusses is verified using analytical and numerical examples from the literature, showing compatible results. In the context of soil mechanics, the code is also verified through examples, considering homogeneous, stratified soils with three-dimensional stress propagation. Finally, examples are studied considering the soil-structure interaction, where the degree of influence of the soil-structure interaction on the results of the requesting efforts is evaluated.
Influence of the train speed in the performance of a ballastless track in a transition zone
Authors: Ana Luísa Gonçalves Ramos  , António Gomes Correia  , Aires Colaço  , Rui Calçada
Published: January 2025

The ballastless track is the most popular railway system nowadays. This is due to the associated reduced maintenance costs and operations. Indeed, in recent years there has been a shift from the ballasted track to the ballastless track, mostly in Asia, but also in Europe. Considering both railway structures, their performance in transition zones is a major concern of the Railway Infrastructure Managers. These areas are characterized by an abrupt change in the track stiffness, which leads to the development of differential settlements and the growth of dips and bumps, accelerating the degradation of the track. Thus, it is crucial to have a methodology able to accurately predict the performance of the ballastless tracks in transition zones, mostly in the scope of high-speed lines. This work presents a detailed analysis regarding the evaluation of the performance of a ballastless track in an embankment-tunnel transition zone considering the influence of the train speed. In this analysis six different train speeds were adopted: 220 km/h, 360 km/h, 500 km/h, and 600 km/h. Moreover, the influence of the critical speed is also evaluated. The adopted and developed methodology is a novel and hybrid approach that allows including short-term and long-term performance, through the development of a powerful 3D model combined with the implementation of a calibrated empirical permanent deformation model.
Corrosion impact analysis: a numerical model for reinforced concrete structures using the Finite Element Method based on Position
Authors: Chiara Pinheiro Teodoro  , Rogério Carrazedo  , Rodrigo Souza de Melo
Published: January 2025

Reinforced concrete (RC) structures face environmental challenges like carbonation and chloride ingress, leading to decreased stiffness, serviceability, and security. A key issue is accurately simulating structural responses to environmental effects and their impacts. This article addresses this by proposing a numerical model based on the Finite Element Method with Positions (FEMP), employing frame elements to forecast post-corrosion structural behavior. Subsequently, a probabilistic study is conducted using Monte Carlo simulations to predict failure probabilities amidst changing environmental conditions. The study reveals corrosion's significant impact on structural stiffness and a high probability of failure within 50 years. These findings underscore the necessity of constructing structures with future climate change challenges in mind.
Sensitivity Analysis of Oil Well Cement Pastes Under Creep
Authors: Alfredo Quiroga Flores  , Ana Beatriz de Carvalho Gonzaga e Silva  , Vivian Karla Castelo Branco Louback Machado Balthar  , Eduardo de Moraes Rego Fairbairn
Published: January 2025

Creep is the phenomenon of increasing deformation under sustained loads. Cement pastes, used for cementing oil wells, are subjected to this phenomenon through the application of mechanical, temperature, and pressure loads. These pastes under these conditions are the focus of this study. Consequently, this work uses the creep functions developed in Vitor Colimodio's master's dissertation, defended at COPPE research center of Universidade Federal do Rio de Janeiro, and applies them on the behavior of concrete casings for cementing oil wells. A sensitivity analysis was performed to evaluate the importance of each variable. The Tencim software, developed at COPPE, was used to perform the models.
Thermal behavior of air-fluid in triangular cavities of 3D printed concrete walls
Authors: Rodrigo do Val Andrade  , Oscar Aurelio Mendoza Reales  , Ana Beatriz de Carvalho Gonzaga e Silva  , Eduardo de Moraes Rego Fairbairn  , Henrique Conde Carvalho de Andrade
Published: January 2025

The civil construction industry has shown increasing interest in 3D printing technology due to its ability to produce highly complex structures with different internal wall geometries using concrete as the raw material. With the advancement of technology, the use of numerical modeling software has become necessary to simulate heat transfer and the thermal performance of objects developed through 3D printing. The objective of this work is to simulate heat transfer in a wall geometry obtained by 3D printing, featuring triangular cavities filled with air, and to compare the results using two different approaches. Initially, computational simulation with air voids in a wall as solid elements will be presented using DIANA FEA software, and subsequently, the air voids will be treated as a fluid using OpenFOAM software. The comparison between the two simulations will be presented, highlighting the influence of modeling air voids on the thermal properties of 3D-printed structures.
Comparison of Operational Modal Analysis Methods for Aerospace Applications
Authors: Hugo Eduardo García Sosa  , Cássio Buss Mainardes  , Sergio Henrique da Silva Carneiro
Published: January 2025

Structures engineered by professionals must endure various loads contingent upon operational requirements. Among these, dynamic loads like vibrations pose a significant challenge due to their potential to induce undesired behavior, leading to damage, operational impracticality, and even structural failure. Therefore, comprehending how structures respond to vibrations is paramount for ensuring integrity and safety. Operational Modal Analysis (OMA) emerges as a crucial tool in this pursuit. OMA serves as a potent technique for assessing modal parameters dictating structural dynamical behavior, encompassing natural frequencies, damping ratios, and mode shapes. The OMA process involves measuring structure responses to assumed white-noise input, generating correlation functions in the time-domain, and subsequently deriving auto-power and cross-power spectra families. What sets OMA apart from other methods like experimental modal analysis (EMA) is its utilization of real boundary conditions and operational inputs, enabling analysis without interrupting structure operations. This paper focuses on applying OMA to various structures, comparing established modal extraction methods from literature, specifically the Numerical Algorithm for Subspace Identification (N4SID), and the Stochastic Subspace Identification methods SSI-COV and SSI-DATA. Initially, the OMA method is validated on a steel cantilever beam, where modal parameters estimated by these methods are compared with theoretical data derived from modal simulations using the Finite Element Method, ensuring the accuracy of OMA results. Subsequently, a wing from an aircraft and a drone structure are subjected to testing to estimate their modal parameters for operational safety assurance. Results indicate a good correlation between theoretical and experimental modal parameters across all tests, affirming the efficacy of the OMA approach. Overall, this paper explores the application of three Operational Modal Analysis (OMA) methods across diverse structures pertinent to the aerospace industry, aiming to unveil their dynamic characteristics.
Implementation of Gaussian quadrature in Python program for grillages with curved elements
Authors: Ricardo José Almeida Rego  , Lucas Trindade da Silva  , Luis Fernando Sampaio Soares
Published: January 2025

This paper demonstrates the development of a Python program for linear-elastic structural analysis of grillages featuring circumferential arc-shaped and regular straight elements subjected to concentrated and distributed loads. The algorithm is based on the Finite Element Method. The force method was employed to compute the flexibility matrix, followed by the determination of the stiffness matrix and load vectors through inversion. A Gauss-Legendre Quadrature was incorporated in order to have a better control on accuracy for displacements, rotations, forces and moments. Results were validated through comparisons with literature data and similar software where curved structures are simulated using numerous straight elements. It was demonstrated that the Python-based program yields results closer to the exact solution with simplified input data, highlighting the effectiveness of both programming language and Gauss quadrature technique in structural analysis.
Numerical simulation in the wind action analyses in silos with a windbreak
Authors: Gabriel Fernandes Andrade  , Marco Donisete de Campos
Published: January 2025

A windbreak, by definition, is the planting of single or multiple rows of trees to reduce the wind speed to leeward. In this work, was analyzed the efficiency of windbreaks in attenuating the external pressure coefficients of wind action in silos. The methodology was validated using the Ansys Workbench software, considering a height/diameter ratio equal to 0.5. In other applications was studied the influence of the neighborhood on the external pressure coefficients and streamlines between geometrically identical silos. The significant reduction in external pressure coefficients was verified, highlighting windbreaks as an option to protect silos in open areas with high wind loads.