bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoanalytical studies on cross-linked polyurethane networks: effect of polyol molecular weight and structure of cyclodextrins
Authors: Cakić Suzana M. , Ristić Ivan S. , Holló Berta B. , Nikolić Vesna D. , Nikolić Nada Č. , Rakić Srđan , Ilić-Stojanović Snežana
Published: April 2024

The applications of polyurethanes (PURs) have increased in recent years, because of their properties which can be adjusted according to their chemical structure. In this paper the preparation and detailed characterization of designed polyurethanes are reported for potential pharmaceutical applications. Two series of polyurethane networks were synthesized by using β-cyclodextrin (βCD) or hydroxypropyl-β-cyclodextrin (HPβCD) as cross-linker for alicyclic isophorone diisocyanate (IPDI) and polyethylene glycols (PEG2000 or PEG6000) or poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (BLOCK 1100). The PURs were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). To visualize the morphology of the PUR samples, scanning electron microscopy (SEM) was used. FTIR assignments confirmed the formation of urethane linkages. XRD patterns revealed that the crystallinity decreased mainly due to the crosslinking process. The thermal stabilities of two series of polyurethanes have been correlated with their soft-segment molecular weights and structure of cross-linker. The increase of melting point is attributed to an increase in the size of the crystallites or an increase of complete crystalline phase due to the greater phase separation the hard and soft segments. The results from the SEM micrographs showed that βCD contributes to the microphase separation. The results showed that by varying the cyclodextrins as a cross-linker and the chain length of the soft segments, the stated properties of polyurethanes as potential drug delivery carriers can be changed.
Uric acid/HDL-C Ratio May Predict Significant Coronary Artery Stenosis: Intravascular Ultrasonography Study
Authors: Demir Ömer Furkan , Arslan Abdulsamet , Kınık Mustafa , Şensoy Barış , Demir Günseli
Published: April 2024

Background: There may be severe difficulties in determining the severity of LMCA lesions. The use of intravascular ultrasound (IVUS) facilitates the decision about the lesion severity in these patients. The aim of this study was to investigate the relationship between UHR and lesion severity in patients who have undergone LMCA IVUS.
Methods: The study included 205 patients who were determined with ICS in LMCA and underwent an IVUS procedure. In the IVUS measurements of these patients, the plaque burden (PB) and the minimal lumen area (MLA) showing lesion severity were measured.
Results: The patients were separated into two groups according to the plaque burden values as those <65% and ≥65%. The UHR values were determined to be significantly higher in the high plaque burden group (479.5 vs. 428.6, p:0.001). When the patients were separated into two groups according to the MLA values (<6mm2 and MLA ≥6mm2), the UHR values were determined to be significantly higher in the group with low MLA values (476.8 vs. 414.9, p<0.001). In the ROC analysis performed according to the MLA and plaque burden values, the UHR cutoff value of 450 was found to have similar sensitivity and the same specificity for both parameters.
Conclusions: The results of this study suggested that there is a relationship between the UHR parameter and MLA <6mm2 and plaque burden ≥65%, which are independently evaluated as critical in IVUS, and this could predict anatomically significant lesions in patients with a moderate degree of LMCA stricture.
Evaluation of cereblon expression in gastrointestinal tract tumors
Authors: Degirmenci Mustafa
Published: April 2024

Purpose: This retrospective study has aimed to determine the possible prognostic significance of cereblon (CRBN) expression in gastrointestinal tract tumors.
Methods: In this study, cases of gastrointestinal tract tumors including neuroendocrine tumors (n:38), gastric adenocarcinomas (n:152) and colorectal carcinomas (n:87) diagnosed in the Pathology Laboratory of Tepecik Training and Research Hospital between 2008 and 2018 were evaluated. We investigated the presence of CRBN protein expression in tumor tissues using IHC staining. The relationship between CRBN expression and various prognostic factors was analyzed.
Results: Most of the cases were male (n=179, 64.6%). The mean age of the patients was 60.5± 13.1 years. Overall survival in malignant cases was 30.5±21.8 months, with the shortest survival of 24.7 months in gastric carcinomas. CRBN expression was detected in 92 (33.2%) cases. CRBN positivity rates were highest in neuroendocrine carcinomas (55.6%) and lowest in gastric carcinomas (22.4%). The presence of CRBN expression was statistically significantly different among tumor types (p<0.001). When each group was evaluated separately, a statistically significant relationship was detected between CRBN expression and survival only in gastric carcinomas (p= 0.036). However, contrary to expectations, survival was shorter in patients with CRBN- positive tumors.
Conclusion: In cancer treatment, it is very important to identify new targeted treatment options, especially for aggressive tumor types. Since some currently used immunomodulatory drugs target CRBN protein, the use of immunomodulatory drugs may be considered in addition to current therapies in the treatment of solid tumors expressing high levels of CRBN.
Bariatric Surgery- Current perspective and present challenges- A Narrative Review
Authors: Amjad Maryam , Katta Maanya Rajasree , Kanso Nourhan , Khan Muhammad Hamza , Khurshid Fatima , Anwar Mariam , Fatima Sehar , Ghosh Bikona
Published: April 2024

Diet, exercise, cognitive behavioral therapy and pharmacotherapy are the means to assist patients to lose weight, with bariatric surgery being the most effective. Over the last two decades, due to increased awareness of the systemic benefits of bariatric surgery, as well as the safety and the wider use of the laparoscopic approach, has made bariatric surgery flourish.
Obesity-associated mortality and co-morbidities such as type 2 diabetes, hypertension, dyslipidemia, obstructive sleep apnea, renal dysfunction and depression improve significantly with bariatric surgery. The mechanisms of weight loss extend beyond restriction and malabsorption and include changes in hunger and satiety, food preferences, and possibly energy expenditure. Despite its safety and efficacy, bariatric surgery is under utilized as less than 1% of adults with obesity receive it. In view of the evolution of obesity into a global threat, access to bariatric surgery should be revised, whilst developing safer and less invasive weight loss treatments. In summary, this narrative review provides a valuable resource for the management of obesity with bariatric surgery. By providing a comprehensive analysis of the latest evidence and elucidating the underlying mechanisms, this review seeks to establish a foundation for the development of innovative strategies in the management of obesity.
Sundaixanthone A from the stem bark of Calophyllum sundaicum P. F. Stevens
Authors: Lizazman Mas Atikah , Mian Vivien Jong Yi
Published: April 2024

Sundaixanthone A, a new compound from the class of xanthone was isolated from Calophyllum sundaicum collected in Sarawak, Malaysia. The compound was characterized using NMR techniques, and identified as 12-(2,3-dihydroxy-3-methylbutyl)-5,10-dihydroxy-2,2-dimethyl-2H,6H-pyrano [3,2-b] xanthen-6-one.
Implementasi Metode Ward & Peppard dalam Perancangan Blueprint Smart Village Sudagaran
Authors: Kusumawardani Dwi Mustika , Wiguna Citra , Rakhmadni Diovianto Putra , Br. Karo Ella Manisa
Published: April 2024

According to Village Law No. 6 of 2014, villages play an important role in the implementation of village development policies. The government-mandated village regulations must be followed in order to improve the quality of life in rural communities. This can be accomplished through the enhancement of services and the development of sustainable villages. The smart village concept is one of the strategic steps for improving village development. Smart village indicators are adapted from smart cities, one of which is smart government, to map village development. Smart government can increase community members' empowerment and involvement in public management, as well as transparency in decision-making and the maintenance of governance that emphasizes the capacity of village officials, village institutions, and the delivery of basic services. To begin the process of creating a smart village, a blueprint must be created. The Ward and Peppard method can be used to create the design. The Ward and Peppard method is used in this study, and it begins with a mapping diagram that includes value chain analysis, SWOT, key performance indicators, McFarlan, and PEST. The design of the village development strategy is carried out by analyzing the organization's internal and external conditions, including business processes and IS/IT infrastructure. The research results in a smart village blueprint design document, which is expected to be implemented to realize the village in building village social resilience in a sustainable manner, as well as providing basic government services in a precise and transparent way.
Classification of SWOT Statements Employing BERT Pre-Trained Model Embedding
Authors: Thamrin Husni , Oktafiani Dewi , Rasyid Ibrahim Ihsan , Fauzi Irfan Miftahul
Published: April 2024

SWOT analysis is a highly effective method for organizations to develop strategic planning and gain widespread adoption by various institutions, industries, and businesses. The importance of SWOT analysis lies in its ability to provide a comprehensive assessment of an organization's internal and external factors. Despite its advantages, there are several challenges in its implementation, such as the challenge to identify the four elements of SWOT and to put statements into their correct position as strength, weakness, opportunity, or threat. This study aims to determine the best SWOT statement classification from a combination of using BERT models as feature extraction technique and compare it with traditional method of TF-IDF. The SWOT statement is input to the model to get a vector as a sentence representation. More similar vector representations indicate the closer meaning of the sentences. The similarity is the basis for the classifier to determine whether a sentence falls into the domain S, W, O, or T. We examined two classification algorithms, namely Support Vector Machine (SVM) and Naïve Bayes Classifier (NBC). Data consists of 635 SWOT statements from study programs of a higher education institution. Five combinations of feature extraction techniques and classification algorithms were tested. The study finds that SBERT model embedding in conjunction with support vector machine classification yield the best performance with an accuracy of 0.73 and an F1-score of 0.738. It outperforms the more traditional method of feature extraction of TF-IDF and other combinations using the Naive Bayes Classifier.
Audit Tata Kelola Teknologi Informasi dalam Mendukung Penerapan Good Corporate Governance (Studi Kasus PT XYZ)
Authors: Simatupang Agustin , Adrianto Henricus Judi
Published: April 2024

The development of Information Technology (IT) is rapidly growing and has increasing risks. Based on the Decision of the Ministry of State-Owned Enterprises S-122-MBU-DSI-05-2021 regarding the implementation guidelines for the assessment of IT Maturity Levels, companies are required to carry out an independent assessment of the maturity level of information technology. This research aims to assess the governance of IT risk management using the COBIT 2019 framework. The research method was carried out using descriptive qualitative methods using the COBIT 2019 framework and literature review, as well as through interviews, observations, questionnaires and review of company documents. The assessment results showed an average maturity level of 3.00 (Established) for 2 COBIT 2019 processes which were considered relevant to Information Technology Risk Management. On average, the 2019 COBIT processes have been implemented at PT XYZ is already running well with the IT risk management maturity level at level 3 and initiatives are still needed to reach maturity level 4 or better. Maturity level 3 means the process has been managed and achieved its goals in a more organized manner using organizational assets and resources. The process has been well defined with policies and standard operating procedures for the process and is carried out in accordance with good risk management and supports the Good Corporate Governance. In the process of increasing the maturity level of information technology risk management to higher level, there are 7 (seven) main recommendations to be implemented so that the information technology risk management process can improve and the implementation of recommendations from the assessment results will be prioritized in the implementation roadmap IT according to Company needs and targets.
Evaluasi Keamanan Sistem Informasi Menggunakan Fuzzy FMEA Berbasis Framework ISO/IEC 27001:2013 untuk Meningkatkan Keamanan Informasi
Authors: Kusnandar Aris
Published: April 2024

Very few organizations are not aware of the importance of information security, even though information security is important to the running of an organization. Dinas Kependudukan XYZ faces a number of information security threats from various sources. Every security threat such as information theft, fraud, vandalism, and computer hacking will affect the organization. This research uses the ISO/IEC 27001:2013 framework as a method for. analyze risks. The risk value calculation uses the FMEA method which is integrated with the fuzzy method to determine the risk level of information security threats based on ISO/IEC 27001:2013. The research results are in the form of a risk processing report containing a list of risk priorities and control plans according to the ISO/IEC 27001:2013 standard. The information security risk priorities obtained in this research were 13 very high priority and 10 high priority. This proves that the organization has not complied with standard security/information procedures so it needs to document security policies based on ISO/IEC 27001:2013 to provide a sense of security and increase trust in the public.
Spillovers across global stock markets before and after the declaration of Russia’s invasion of Ukraine
Authors: Krishna Sharma Raavinuthala Satya , Jain Girish , Patel Gokulananda
Published: April 2024

Since the financial meltdown, studies on systemic risk and financial contagion have gained currency. Events like the COVID pandemic and the Russian invasion of Ukraine have fueled such an importance. This study examines the impact of the invasion on volatility transmissions across major stock markets worldwide. The stock indices considered in this study are ASX 200, ESTOXX 40, FTSE 100, HNGSNG, NIFTY 50, NIKKIE, and S&P 500. The work uses Vector Auto Regression (VAR) to study the transmission of returns. Later, the work performs Dynamic Conditional Covariance-Generalized Auto Regression Conditional Heteroskedasticity (DCC-GARCH) on the residuals where the transmission of returns was significant. The DCC-GARCH (E-GARCH) shows that all the asymmetric transmissions are negative. The study finds that co-movements of stock returns for the following pairs: ESTOXX 50-S&P 500, NIFTY 50-FTSE100, NIFTY 50-NIKKIE, NIKKIE-ESTOXX 50, S&P 500-NIFTY 50, and SP500-HNGSNG significantly intensified after the declaration of invasion. Such intensification of co-movements does establish the contagion effect triggered by invasion. The study shows that ESTOXX 50, which has the closest geographical proximity to the war zone, happens to be the highest generator of spillovers.
FACILE SYNTHESIS OF FUNCTIONALIZED UiO-66-TYPE MOFs FOR CO2 ADSORPTION
Authors: Ge Jinlong , Jin Xiaoqi , Zhang Liyuan , Jiao Yuhong , Wang Qiuqin , Wang Yongkui , Gao Yan , Geng Jiaojiao , Wang Tianqi
Published: April 2024

The metal-organic frameworks (MOFs) UiO-66-NH2, UiO-66-2,5-(OH)2, UiO-66-NO2, UiO-66-NDC, and UiO-66-BPDC were synthesized under solvothermal conditions using different functionalized organic linkers. The structures and properties of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. The crystal structures of these functionalized UiO-66(Zr) forms were similar. A series of functionalized UiO-66(Zr) samples were used in the adsorption of carbon dioxide (CO2). UiO-66-NH2 had the highest CO2 adsorption capacity (about 3.35 mmol g-1) due to its small polar –NH2 group. The performance of UiO-66-NH2 in CO2 adsorption at different temperatures was also determined. The amino-functionalized material possessed better adsorption properties at 273 K than at 303 K, while the CO2 working capacity of UiO-66-NH2 was fully recovered after cyclic regeneration.
A Novel Disulfidptosis-related lncRNAs Prognostic Signature for
Prognosis Predicting and Immune Microenvironment
Characterization in Breast Cancer
Authors: Chen Xi , Yang Chen
Published: April 2024

Introduction:

Breast cancer (BRCA) is one of the leading causes of cancer-related death in women. The improvement of the BRCA risk assessment method is of positive clinical significance. Although many clues showed the potential role of disulfidptosis in BRCA as a novel type of programmed cell death, whether disulfidptosis is involved in BRCA tumorigenesis remains unclear.

Method:

We used LASSO-univariate Cox analysis and multivariate Cox analysis to identify six disulfidptosis-related lncRNAs (DPLs) that correlated with BRCA clinical outcome and confirmed that these DPLs were independent prognostic factors for BRCA
(YTHDF3−AS1, AC002398.1, AL451085.2, AC092718.4, AC097662.1 and
AC053503.5). The BRCA risk prognosis model was subsequently established based on
these DPLs.

Result:

After verifying the model reliability in predicting prognosis, immune infiltration
and somatic mutation analysis showed significant differences in the immune microenvironment and mutation of DPLs by risk stratification. Immunotherapy response and drug
resistance analysis suggest the reference value of DPLs in clinical individualized therapy.

Conclusion:

The abnormal expressions of selected DPLs were further validated by the
BRCA cell line experiment. Our results shed new light on the role of DPLs in BRCA.
Structural Insights into Mouse β3-adrenergic Receptor: A Promising Target for Obesity and Diabetes Therapeutics
Authors: Gangadhara Vijayalakshmi , Gawli Kavishankar , Abraham Asha
Published: April 2024

Background:

Investigating the structural attributes of the murine beta3-adrenergic receptor
(β3-AR) is imperative for comprehending metabolic regulation, given its close resemblance to the
human β3-AR. This receptor holds promise as a target for novel drug development against obesity
and diabetes. Despite its potential, the absence of knowledge regarding the structure of murine β3-
AR hampers a comprehensive understanding of its functionality.

Objective:

Our study aimed to model the three-dimensional (3D) structure of murine β3-AR through
various molecular structure prediction and simulation techniques, thus addressing the existing gap in
structural information.

Methods:

Employing diverse structure prediction programs, we refined the predicted structure of
murine β3-AR. Primary sequence analysis offered insights into charge distribution, stability, and
hydrophobic properties. The binding sites were identified in the modeled structure. Molecular Dynamics
(MD) simulation provided the structural stability and dynamic behavior of the predicted β3-
AR structure.

Results:

The β3-AR protein exhibited specific characteristics, including a pI of 9.57, an aliphatic
index of 98.35, a GRAVY score of 0.289, and the presence of conserved motifs and disulfide linkages.
Utilizing the programs such as Phyre2, Swissmodel, I-Tasser, and AlphaFold2, we generated a
3D model of murine β3-AR. Subsequent refinement using ModRefiner revealed a structure comprising
13 helices, 2 strands, and 21 turns. The Ramachandran plot indicated favorable regions for 93.2%
of residues, with minimal deviations. A 50 ns MD simulation demonstrated the consistent stability
and integrity of the β3-AR protein. The top three binding pockets were identified based on varying
areas and volumes. Dynamic behavior within residues Ser 252 and Arg 253 was observed, indicating
flexibility in conformation. This study marks the first-ever exploration, offering initial structural
insights into murine β3-AR.

Conclusion:

This study underscores the critical role of computational approaches in predicting the
3D structure of β3-AR. We derived a refined model by employing diverse prediction techniques,
elucidating key features. The findings emphasize the significance of this methodology in comprehending
the structural foundation of β3-AR, providing valuable insights for targeted medication development
against conditions such as obesity and diabetes.
Constructing a Novel Instrument to Measure Social-Emotional Self-Regulation in Students Aged 8-18
Authors: Walker Simon P. , Walker Jo
Published: April 2024

Background

The authors identified a need for instruments that measure a task model of self-regulation as opposed to an emotion model of self-regulation. Such instruments are particularly applicable to student populations.

Objective

This paper explains the construction of one such instrument, Steer Tracking. A four-factor bi-polar conceptual model of four necessary self-regulatory tasks is presented: Trust of Self, Trust of Others, Self-Disclosure and Seeking Change.

Methods

A novel assessment method was developed, requiring a participant to imagine a mental space in which they perform the four self-regulatory tasks. The instrument was deployed in populations of students aged 8-18 attending UK primary and secondary schools. Principal Component Analyses evaluated the proposed four-factor structure across two age groups: 8 to 12 years olds (n = 2171) and 13 to 18 years old (n = 658). A Support Vector Machine (SVM) model in a separate sample (n = 2518) evaluated the assessment’s utility in identifying students who display risk on three wellbeing measures: experiencing bullying, thinking about or engaging in self-harm, and struggling to cope with pressure at school.

Results & Discussion

Analyses provided initial support for the validity of the conceptual model and its ability to identify at-risk students. Key instrument features such as non-standardisation and generalised versus in-school comparison are explained.

Conclusion

Application, relevance and potential benefits of the Steer Tracking instrument for educators and school managers are explored.
KASSANDRA Model: Detecting Dangerous Traffic Conditions By Modeling Drivers’ Internal Stress Energy
Authors: Nagkoulis Nikolaos , Nalmpantis Dimitrios , Bearman Nick
Published: April 2024

Introduction

This paper introduces an innovative method to reduce car accidents by employing mechanical concepts and energy conservation to model drivers’ reactions in unexpected scenarios.

Methodology

The approach involves formulating equations to define drivers’ “internal stress energy,” indicative of their propensity for aggressive driving under time pressure. A spatiotemporal model was developed using traffic data from Highways England and accident data from Transport for London, analyzing around 200 car accidents with data from 80 cameras over two years.

Results and Discussion

Findings suggest a correlation between drivers’ internal stress energy and car accidents, highlighting the predictive value of the proposed equations in assessing road segment dangers. More specifically, using the proposed model with 15-minute timeframes increased car accident prediction four (4) times compared to the evenly spatiotemporal car accident distribution. With smaller timeframes, e.g., two (2) minutes, or with real-time data, its predictive power would be significantly higher!

Conclusion

The equations developed offer a promising tool for estimating and preventing car accidents by modeling the influence of drivers’ stress on driving behavior.
Influence of an optical strain rate controlled tensile testing method on mechanical properties of sheet metals
Authors: NAUMANN David
Published: April 2024

Abstract. Precise material characterization is a key factor not only for representative finite-element-analysis (FEA) in production technology, but also for product development in general. Hereby, the tensile test is of particular importance, as it can be used to determine the most relevant material parameters. These are used to ensure a better process and tool design but therefore material behavior has to be determined to a high level of precision [1]. Especially in the field of metal forming, strain rate sensitive material properties like work hardening, yield point or tensile strength need to be measured at constant strain rate to provide coherent data for material models in numerical forming simulations [2]. Current testing procedures control the strain rate with a feedback control, in which various measuring systems can be used. From this comes the necessity to investigate the influence of a strain rate controlled tensile testing procedure compared to a conventional crosshead-displacement controlled one. Thus, in the scope of this study, an optical strain rate controlled (OSRC) tensile test procedure with a digital image correlation (DIC) system, and a universal testing machine (UTM) was developed. The resulting mechanical properties and the evolution of the strain rate during the test of the steel DP600 (CR330Y590T-DH) and DC05 (CR4) were analyzed at a nominal strain rate of 0.4 %/s. In addition, the results obtained from displacement strain rate controlled (DSRC) tensile tests were compared. The results demonstrate that OSRC testing method enables the measurement of mechanical material properties at a higher level of precision in terms of constant strain rate compared to DSRC procedure.
Effect of different oxide layer shares on the upsetting of titanium aluminide specimens
Authors: DÖRING Sebastian
Published: April 2024

Abstract. By ball milling in a low-oxygen atmosphere, it was possible to show that titanium aluminides (TiAl) can be processed into components by pressing and sintering in the same atmosphere. The properties (e.g. hardness and density) that can be realised with established processes such as field-assisted sintering (FAST) or hot isostatic pressing (HIP) were not achieved. Pores in the component are closed by forming processes, which improves the mechanical properties. In this work, powder-metallurgically processed TiAl was hot-formed in a low-oxygen atmosphere. The forging parameters and pre-consolidation were characterised with regard to their effect on the component properties. Force, hardness and porosity measurements as well as metallographic analyses were used to evaluate the process and the resulting specimens. It was found that a pre-consolidation and a higher degree of deformation lead to a lower porosity and a higher hardness.
Influence of the forming pre-strain on the fatigue performance of upset bulge formed tubes
Authors: BECHLER Jan
Published: April 2024

Abstract. Safety-relevant components in the automotive industry must fulfill stringent requirements for performance, particularly in endurance. The height adjustment system in a car seat is one example. The height adjustment system is made up of sheet metal parts which are joined with steel tubes through axial compression – also referred to as upset bulge forming. As a result of the forming process, initial cracks occur at the inner bending radius of the tubes which, along with the forming history, decrease the fatigue life by 450%. The aim of this study is to identify whether the initial cracks occur due to shear bending generated by the process or elastic springback. The influence of the elastic springback on the crack initiation is investigated through bending experiments of DP600, Al99.5, and 1.4301. To prevent elastic springback, the specimens are secured with screws post-bending and are removed afterwards. The bending radius is investigated with respect to the equivalent plastic strain to determine a minimum without failure. Cyclic tests of bulges with two different forming histories are tested to investigate the influence of the forming pre-strain on the fatigue behavior. In all bent materials, initial cracks occur at the inner bending radius where the elastic springback increases the initial cracks and Scanning Electron Microscopy (SEM) analysis confirms shearing as the cause. It was also found the grain shape and orientation have a significant influence on the crack propagation in the forming zone of the tube through the upset bulging process.
Preliminary study on the impact of thermal processing on the performances of parts obtained by fused deposition modeling (FDM)
Authors: LORENZONI Margaux
Published: April 2024

Abstract. Additive Manufacturing (AM) allows to build complex geometries while generating less waste than conventional processes such as machining. However, in AM processes such as Material Extrusion (MEX), workpieces tend to have low mechanical properties, low dimensional accuracy as well as rough surfaces. Indeed, several pre-processing and post-processing techniques exist to attempt to control these concerns. One post-processing method, namely thermal annealing, is already widely used with metallic parts. However, the influence of this technique has yet to be tested on mechanical properties such as tensile properties, dimensions, and surface roughness for polymer parts obtained by MEX and, particularly, by Fused Deposition Modelling (FDM). This paper aims to determine the relevance of using thermal annealing as a post-process to enhance FDM-obtained parts tensile properties while keeping in mind their dimensional and surface roughness aspects.
Evaluation of correlations between principal axes in uniaxial tensile tests of aluminum based on Mohr’s strain circle
Authors: IIZUKA Takashi
Published: April 2024

Abstract. Anisotropic elasticity is expected to contribute significantly to material deformation and should be considered in nature. Therefore, in this study, the correlations between elastic and plastic strains are investigated, with emphasis on the principal axes. In an experiment, strains are measured in eight directions during tensile tests, and Mohr’s circles are derived for elastic and plastic strains. The planar anisotropy of elasticity and plasticity for some mechanical properties is confirmed, and the angle deviations between the principal axes of stress and strain are compared for elasticity and plasticity. In the case of aluminum, for both elasticity and plasticity, the planar anisotropy of its mechanical properties indicates four-fold symmetry, and the principal axes of elastic and plastic strains are identical, with some angle deviations from the principal axes of stress.
Characterization of the superplastic behavior of a Ti6Al4V-ELI alloy bilayer sheet
Authors: GUGLIELMI P.
Published: April 2024

Abstract. The aim of the present work is to investigate the superplastic behaviour of a bilayer Ti6Al4V-ELI to numerically design a full custom prosthesis manufacturing process by means of SuperPlastic Forming (SPF); the bilayer was composed by: (i) a monolithic Titanium blank (cut by a rolled sheet); (b) a porous blank cut by a billet produced by Hot Isostatic Pressing (HIP) and subjected to a Solid State Foaming (SSF) heat treatment. Experimental bulge tests aimed to evaluate the effects of both the initial porosity level of the HIPed layer and the temperature (850 and 900 °C) of the SPF process. The bilayer sample was deformed by a constant argon gas pressure and the time evolution of the dome height was recorded during the test in order to be used as target in the IA to determine the constants of the rheological model of the porous layer, being the behavior of the monolithic layer already known. A 2D FE model of the free inflation test was integrated in an automatic optimization procedure with the aim to minimize the error between the calculated and the acquired dome height vs time curve. Finally, the obtained material constants determined were used to design the SPF process by means of the numerical simulation, identifying as a case study a zygomatic full custom prosthesis. The initial porosity level resulted to poorly affect the superplastic behavior of the bilayer at 850 °C; on the contrary, when increasing the temperature up to 900 °C, an evident reduction of the forming time was obtained. Numerical simulations showed that at 900 °C it is possible to obtain the very complex geometry of the adopted case study in about 50000 seconds.
Tension-compression asymmetry of ferritic stainless steel sheet
Authors: Sekiya Koki
Published: April 2024

Abstract. The strength differential effect (SDE) (i.e., the tension-compression asymmetry of stress-strain curves), for a ferritic stainless steel sheet was measured using an in-plane compression test. It was found that the in-plane compressive flow stress was 4-7% higher than the uniaxial tensile flow stress in both the rolling and transverse directions. In addition, bending moment-curvature curves were obtained from a pure bending test. These curves were found to be in good agreement with those calculated with SDE taken into account. Thus, the validity of the measured SDE was confirmed by the bending experiment.
Measurement of shear deformation behavior in thickness direction for a mild steel sheet
Authors: HAKOYAMA Tomoyuki
Published: April 2024

Abstract. The anisotropy parameter of the through-thickness shear for a hot-rolled mild steel sheet was determined by comparing the measured and simulated deformation behaviors. A tensile test using a strip specimen with a stepped shape in the thickness direction to apply the through-thickness shear deformation at the center of the specimen was conducted. Finite element analyses were performed by changing the anisotropy parameter M of the Hill ’48 yield function. The measured through-thickness shear strain γ_zx was compared with the simulated one to identify the parameter M. In addition, plate compression simulations were performed to evaluate the effect of the through-thickness shear anisotropy on the deformation behavior during plate compression.
Inverse estimation of material model parameters using Bayesian data assimilation
Authors: YAMANAKA Akinori
Published: April 2024

Abstract. This study proposes a new method for the inverse estimation of the parameters included in material models from full-field measurement data that are obtained using the digital image correlation method. This approach is based on data assimilation according to the Bayes’ theorem (Bayesian data assimilation). In this study, we demonstrate the assimilation of experimental data obtained from uniaxial tensile, forming, and fracture tests of aluminum alloys into elastoplastic finite element and phase-field crack propagation simulations. The proposed method allows the simultaneous estimation of multiple material model parameters. The Bayesian data assimilation is a promising methodology for estimating the parameters of different material models and constructing digital twins of material deformation.
Bending of third generation steel: Experimental and numerical approach
Authors: ESPANHOL PEREIRA Catarina Sofia
Published: April 2024

Abstract. The development of a new class of material, such as third-generation advanced high-strength steel, requires a deep understanding of mechanical behaviour before its use in industry. One of the critical issues in sheet metal forming processes is dimensional accuracy, which is strongly dependent on the elastic recovery that can manifest itself as springback or spring forward [1]. This undesired defect results from the materials parameters and/or tools geometries [2]. One common way to evaluate the springback/forward is through bending tests. This work aims to investigate the existence of springback/forward on the selected material, its magnitude and dependence on the tool geometry and test the performance of the commercial finite element software Abaqus 2017 to predict the observed behaviour. The 3rd GEN steel, CR980XG3TM produced by US Steel is subjected to V-bending to evaluate the existence of springback or spring-forward. Furthermore, to evaluate the dependence of springback/forward on the tool’s geometry, the V-bending tools with different bending angles (namely, 60º and 90º) and different punch radii (namely, 5º and 10º) are used. The load is applied by a Shimadzu AG-X plus 100kN, and the deformation is measured by digital image correlation (DIC) using the GOM ARAMIS 3D 5M system. Numerical analysis of the bending tests is made using Abaqus 2017 software. The experimental results show that the material exhibits springback and spring forward depending on the tool geometry. The strain distribution through the thickness is correlated with the springback/forward.
A temperature-dependent crystal plasticity model for predicting cyclic loading behaviors of a magnesium alloy
Authors: BONG Hyuk Jong
Published: April 2024

Abstract. In this work, a crystal plasticity finite element (CPFE) model to predict cyclic loading behaviors at elevated temperatures of a wrought magnesium alloy, i.e., AZ31B sheet, is proposed. The temperature-dependent mechanical behavior is systematically modeled by modifying the strain-hardening model. The twinning-detwinning, a key deformation mechanism that occurs during the cyclic loadings in the magnesium sheet, is also modeled based on the well-known predominant twinning reorientation (PTR) scheme. Furthermore, to better predict the detwinning behavior, a concept of residual twin is also introduced and employed in the PTR scheme. The modified strain-hardening and enhanced-PTR model considering the twinning-detwinning are implemented in the CPFE framework. Using the developed model, mechanical responses of the AZ31B sheet under cyclic loading conditions at various testing temperatures up to 200°C are predicted and compared with the experimental data, and the prediction results are promising.
Investigation into the friction and wear behaviour of polymer coated steel
Authors: VENEMA J.
Published: April 2024

Abstract. In the packaging industry, polymer coated steel is used to produce cans and other containers. One of the limitations that can limit production rates is scuffing. Scuffing is local failure of the polymer coating. To understand the failure behaviour of this type of sheet coating, cans have been produced at a range of processing speeds and tribological tests have been performed on polymer coated steel. Linear friction tests were performed under various contact pressures and tool temperatures (20-195 °C). Scuffing generated by the tests were investigated using 3D topography measurements of the surfaces. Several parameters (coating, pressure and temperature) and their interaction determines the frictional and wear behaviour of the polymer. Temperature is a key parameter governing the coating wear phenomena. Surface measurements indicate that similar coating failure defects can be observed in both the linear friction test and in industrial-scale can making. The tests proved that polymer coatings can resist relatively high contact pressure conditions and temperatures. This makes polymer coated steel sheets applicable for a large range of packaging products.
Correlation between sheet formability and joint strength of A1050-O/SPCC butt laser welded tailored blanks
Authors: JIN Jianchen
Published: April 2024

Abstract. Laser-welded tailored blanks are useful for lightweight automobiles. However, three major problems remain unresolved: low joint strength, low formability, and galvanic corrosion. Although considerable research has been conducted on the lap form, the studies on the use of lasers to weld dissimilar metals in the butt form are scarce. For practical applications of dissimilar metal tailored blanks, formability must also be investigated. In this study, Japan Industrial Standard A1050-O aluminum and SPCC steel were welded as dissimilar metal tailored blanks and used for Erichsen, flat punch stretch, and hole expansion tests. Welded materials with different joint strengths were produced to investigate the correlation between joint strength and formability. Two patterns of fracture owing to differences in joint strength were observed during the flat punch stretch test. The results of the formability test confirmed that the formability improved with an increase in the joint strength.
Electrically-assisted forming of 5754 aluminium alloy under different strain conditions
Authors: DOBRAS D.
Published: April 2024

Abstract. Electricity-assisted forming processes can significantly improve material ductility and process efficiency. However, further research into different strain conditions is necessary, for example, in stamping processes. In this study, tensile and deep drawing tests of the 5754 aluminium alloy were carried out with the application of current pulses on a specially constructed experimental setup. The study showed that it is possible to increase the plasticity of the material. The main cause responsible for the increase in plasticity was dynamic recovery.
Influence of toolpath strategies on the final accuracy and thickness distributions in multi-stage incremental forming
Authors: Vanhulst M.
Published: April 2024

Abstract. This study focuses on finding a toolpath strategy for accurately forming geometric details on a preshaped sheet metal part by incremental forming in multiple steps. The final thickness distributions and geometrical accuracy are analyzed for spiraling and dedicated feature toolpath strategies. The results are compared to forming the full part (base shape with details) in a conventional single stage manner. Forming the part in multiple steps did improve the accuracy of the part, by decreasing the underforming of the base shape compared to single stage forming. The observed overforming was highly influenced by the location of the detail. In terms of thickness distributions, the toolpath strategy highly influenced the location of the minimal thickness inside each detail. Here, the dedicated feature toolpath proved to be effective for achieving a more uniform thickness distribution.
Effect of vibration frequency and amplitude on formability in rotational vibration-assisted incremental sheet forming (RV-ISF)
Authors: ZHU Hui
Published: April 2024

Abstract. Incremental sheet forming (ISF) is a flexible manufacturing process, potentially for producing small-batched and customized sheet products. To improve formability of hard-to-form materials, part surface finish and forming accuracy, the rotational vibration-assisted ISF (RV-ISF) has been developed by the University of Sheffield with the use of novel tool designs with either offsets or grooves on the tool surface to introduce both mechanical vibration and localized heating into the conventional ISF process (C-ISF). With the use of double-offset (T2) and four-groove (T4) tools in the experiments, this work studies the effects of tool design and tool rotational speed on sheet vibration amplitude and frequency, as well as their effects on forming temperature and force reduction and formability improvement. Results show that the sheet vibration amplitude is mainly influenced by the tool design, while the vibration frequency is affected by both tool design and rotational speed. RV-ISF with T4 shows greater material formability improvement of AA3003-O due to greater temperature rise and low-frequency-low-amplitude vibration. RV-ISF with T2 results in greater reduction of forming force because of the higher sheet vibration amplitude.
Non-rotationally symmetric joints – Mechanisms and load bearing capacity
Authors: DEVULAPALLY Deekshith Reddy
Published: April 2024

Abstract. Traditionally, joints are cylindrical and rotationally symmetric. In the present study, non-rotationally symmetric joints are used for joining steel and Glass mat-reinforced thermoplastic sheets (GMT). In addition, the study also analyzes the impact of non-rotational symmetric joint rotation on the load-bearing capacity. Single lap joint specimens were fabricated using the In-Mold assembly technique for joining steel sheets with GMT. Tensile shear tests were performed on different orientations of the joint geometry, and it was observed that changing the joint orientation influences the load-bearing capacity. The joints are constitutively modeled using beam elements and the influence of joint rotation on load distribution is examined through a static simulation study.
Topology optimization for the design of additively manufactured hot stamping tools
Authors: YU Daoming
Published: April 2024

Abstract. The hot stamping process makes it possible to obtain complex-shaped parts with high mechanical properties. The hot stamping production rate is driven by the cooling system inside the tool. Improving the efficiency of the cooling system is a key factor as it reduces part production time and thus lower the cost. But an optimized cooling system requires complex internal geometries. That is why the development of additive manufacturing (AM) opens up new and good prospects for designing and making hot stamping tools with high cooling efficiency. This research proposes a two-step topology optimization procedure for hot stamping tools’ design. In the first step, the fluid/thermal topology optimization is used to find the best design for the cooling system. As the printing time and cost for the additively manufactured tool depend on the amount of material used, the second step focuses on removing unnecessary materials in hot stamping tools.
Determining the residual formability of shear-cut sheet metal edges by utilizing an ML based prediction model
Authors: GÖRZ Marcel
Published: April 2024

Abstract. When forming high-strength steel sheet material, premature failure can occur at shear-cut component edges because formability of the base material is reduced due to work hardening caused by the previous punching process. Here, the digitization of production processes provides new possibilities for quality monitoring of such forming and stamping processes. In this context, the present paper deals with a novel machine learning (ML) based method for determining the residual formability of sheet metal materials from measured punching force curves. The specific objective of the study carried out was to develop an efficient and accurate method for predicting the residual formability of shear-cut edges. The methodology proposed for this purpose involves collecting a comprehensive dataset comprising experimental measurements of material properties, cutting conditions and punching-force curves measured during blanking. To determine the residual formability of the sheet metal materials investigated, hole tensile tests were performed and the maximum major and minor principal strain at initiation of cracking were measured. This dataset was then used to train and validate different AI prediction models, which employ machine learning algorithms to establish complex relationships between input parameters and residual formability.