bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Application of Concrete Polymer Materials for Highway Bridges in Japan
Authors: Kawakami Makoto , Demura Katsunori , Wakasugi Mikio , Omata Fujio , Satoh Shinya
Published: November 2024

Recently, the deterioration and renovation of the aged bridges are urgent issue. Approximately 30% of more than 700,000 highway and road bridges in Japan have been in service for more than 50 years. The performance and function of them are required equal to be better than those at the beginning of construction and extend the service life. In addition to above, Japan is also a highly seismic country and there have been frequent damages of the bridges due to earthquakes. Therefore, securing the resilience of the bridges corresponding to robustness, redundancy, resourcefulness and rapidity is strongly demanded. In this study, the current status and practical countermeasures for the bridges to ensure the required performance and function, and to enhance the resilience using concrete polymer materials were investigated and discussed. Concrete polymer materials, which have high strength, high early strength development and high durability, are effective for repair and strengthening to sustain the current performance of structures. The main construction contents are as follows;

It is a construction to replace the damaged reinforced concrete floor slab with a more durable floor slab. Treatment of joints of precast prestressed concrete slab is included.

It is a construction to install high-performance floor slab waterproofing on the waterproof layer.

In order to improve the durability of the bridge, it is a construction to attach reinforcing members to the girder.

Seismic retrofit of concrete piers such as steel jacketing is one of main reinforcement technologies.
Ionic Conductive Polyesters—Assessing the Risk of Corrosion in Steel-Reinforced Concrete
Authors: Weichold Oliver
Published: November 2024

Sensors based on ion-conducting polymers are a reliable alternative to conventional metallic sensors. Formulated as 2K resin, they are quick and easy to install and cost-effective, so that larger sensor arrays with improved accuracy are affordable. The present systems are based on poly(ethylene oxide) or poly(propylene oxide) containing unsaturated polyesters doped with lithium perchlorate and are cross-linked on site with styrene. The curing reaction proceeds even at 0 ℃ and tolerates the presence of water. The best system in this series exhibits a resistivity of 194 Ω·m, which is several orders of magnitude lower than conventional polymers, but also several orders of magnitude higher than metals. The values are sufficient to accurately reproduce the progress of corrosion currents measured with conventional sensors and to detect changes in the humidity of concrete specimen.
Chemically Resistant Concrete Coating Systems with Secondary Raw Materials
Authors: Hodul Jakub , Drochytka Rostislav , Žlebek Tomáš
Published: November 2024

New types of highly chemically resistant coating systems, mainly developed for concrete and metal substrates were subject to experimental testing and evaluation within the project. Secondary raw materials, including solidified hazardous waste (neutralization sludge (NS)), were used as microfillers. The three-layer polymer coating systems, applied using spray technology, were tested at two quality levels – one with a high content of solidification products, and the other with a low content. The microstructure of the epoxy coatings, including an observation of the degree of contamination of the polymer matrix, was investigated using scanning electron microscopy (SEM). It was demonstrated that the substitution of some of the primary filler with a solidification product does not result in the deterioration of the properties of the coating system, such as its adhesion to concrete or chemical resistance.
Alkaline Hydrogels—Multifunctional Materials for Concrete Rehabilitation
Authors: Mrohs Tim , Jung Andre , Weichold Oliver
Published: November 2024

The most important factor for the protection of steel reinforcement in cementitious materials such as concrete is the alkalinity. As well as slowing down the penetration of atmospheric carbon dioxide, it delays to a certain extent the action of chloride ions. Both act at the molecular level in the form of discrete, individually mobile objects that can trigger steel corrosion. Therefore, maintenance materials designed to address these problems at the molecular level benefit from their own high pH value.

To accomplish this an alkaline hydrogel based on diallyldimethylammonium hydroxide was developed which proved to be a multitool for modern building maintenance. The gel structure can be modified in order to tune macroscopic properties such as viscosity and stickiness relevant for applications. These are e. g. the restoration of the alkaline buffer of carbonated concrete, coupling material for the electrochemical chloride extraction, and crack injection, where the gel performs three functions simultaneously.
Fatigue Behaviour of Patch-Repaired and CFRP Strengthened Reinforced Concrete Beams
Authors: James Valontino , Moyo Pilate
Published: November 2024

The service life of corrosion-damaged reinforced concrete (RC) infrastructure can be improved through patch repairs and structural strengthening. However, the effect of varying corrosion damage and patch repair extent has not yet been clearly pronounced. The fatigue performance of corrosion-damaged RC beams that have been patch repaired to varying lengths and subsequently strengthened with carbon fibre-reinforced polymer (CFRP) laminates was evaluated by conducting four-point bending tests and cyclic load tests on simply supported beams. Three criteria were identified to evaluate performance: fatigue life, crack development and stiffness degradation. Various data acquisition techniques, such as neutral axis DEMEC strain targets, strain gauges, linear variable differential transducers (LVDT) and digital image correlation (DIC) were employed to investigate these performance criteria. The experimental results indicated that an increase in corrosion damage and patch repair extent lowered the ultimate static failure load and increased fatigue life. An increase in specimen stiffness was observed for the specimens with the longer damage extent compared to the specimens with the shorter damage extent, where stiffness was gauged in terms of midspan deflection, composite material strain and neutral axis shift. Moreover, the results yielded through the DIC process showed potential to identify potential failure locations, quite early in the specimen fatigue life by comparison of tangential strain, peak vertical deflection and the eventual failure location.
Emerging Materials and Technologies for Next-Generation Sustainable and Resilient Polymer Concrete
Authors: Murcia Daniel Heras , Taha Mahmoud Reda
Published: November 2024

Emerging materials and technologies (EMTs) are introduced to improve the sustainability and resilience of infrastructure. Polymer concrete (PC) has been used for the last 80 years in infrastructure applications where extreme environmental conditions and exposures are dominant. We suggest that EMTs can enable the development of next-generation PC that can contribute to infrastructure resilience and sustainability. This paper presents an overview of the latest developments in using innovative PC by incorporating a myriad of EMTs to improve infrastructure resilience and sustainability. These EMTs include nanotechnology, bio-based polymers, 3D printing, and textile reinforcement. Using nanotechnology, we demonstrate the possible production of a PC with superior ductility and self-sensing capabilities. We also show that a bio-based polyurethane PC with appreciable compressive strength of 20 MPa can be produced. We demonstrate rheological testing of polymer concrete leading to innovative 3D printed polymer concrete structures. We finally show the ability to produce superior flexural load capacity and textile-reinforced PC (TRPC) ductility compared with cementitious textile-reinforced concrete (TRC). We conclude by demonstrating the potential production of 3D printed TRPC. We suggest that the EMTs will enable a quantum leap in using PC to produce sustainable and resilient infrastructure.
Experimental and Numerical Investigation of Patch-Repaired and CFRP-Strengthened Beams
Authors: Moyo Pilate , Mundeli Salathiel
Published: November 2024

Carbon fibre reinforced polymers (CFRP) have emerged as an effective material for strengthening reinforced concrete structures. While many studies have been reported on CFRP strengthening of reinforced concrete elements subject to corrosion, there is a dearth of information on strengthening patch-repaired concrete elements. This paper reports on the experimental and numerical investigation of the behaviour of corrosion-damaged RC beams that have been patch repaired and strengthened with CFRP. Fifteen beams were cast; twelve of these were subjected to simulated corrosion of 5%, and the remaining three were used as control beams. The damage length was varied from 450 mm, 800 mm, 1300 mm and 1800 mm while keeping the depth of patch repair at 105 mm. All the CFRP-strengthened beams failed by intermidiate crack (IC) debonding. The control beams had a lower average crack density than the retrofitted beams. There was an increase in the average crack density for increasing damage lengths. Patch repair combined with CFRP strengthening retrofit method restored the damaged beams load carrying capacity but reduced the beams’ ductility compared to the control beams. The yield loads for patch repaired and strengthened (RS) results increased by 10%, 17% and 20% for beams with 450 mm, 800 mm and 1800 mm damage lengths, respectively. It was also observed that for increasing damage lengths; 450 mm, 800 mm and 1800 mm the peak loads increased by 13%, 20%, 20%, respectively. The experimental results correlated well with the finite element modelling (FEM) results.
Shear Deformability of Reinforced Concrete Beams Strengthened with the FRCM System
Authors: Vegera Pavlo , Grynyova Iryna , Blikharskyy Zinoviy , Khmil Roman , Korobko Oksana
Published: November 2024

The article presents the results of experimental studies of reinforced concrete beams on the shear without transverse reinforcement strengthened by the FRCM system. For the implementation of the research, four experimental samples were designed and manufactured, with cross-sectional dimensions of 200x100 mm and a length of 2100 mm. The beams are designed in such a way that even after strengthening the support areas, the failure occurs due to the shear force. None of the samples is destroyed by the bending moment. The tests were carried out according to the authors’ improved methodology, by testing each sample twice. The samples were strengthened by the FRCM composite system at load levels of 0, 0.3, and 0.5 of the bearing capacity of the control samples. Reinforced concrete beams were strengthened by gluing P.B.O. fabrics in the form of vertical strips with a width of 70 mm, for the possibility of fixing the concrete strains in the support areas. Samples strengthened by the FRCM system are destroyed more smoothly and plastically than unstrengthened beams, and there is no mass fallout of concrete particles. According to the obtained data, graphs of the strain distribution in support area and the isofield of their distribution were constructed. In accordance with the results of the research, the maximum effect of the composite system use for the shear reinforcement was established by 26…57%. With increasing the load level at which the sample is strengthened, the effect of the strengthening decreased.
Interaction Between Polymer and Cement: A Review
Authors: Wang Ru , Zhang Shiwei
Published: November 2024

Polymer-modified cement-based materials are commonly used in engineering applications and have achieved good results. The interactions between polymer and cement have received extensive attention. In this paper, the interaction between them is discussed and summarized by reviewing the existing technologies. Traditional experimental methods do not provide a comprehensive picture of the interaction between polymers and cement-based materials, molecular dynamics (MD) simulations were used recently in the study of inorganic-organic phase interactions. People almost reach a consensus on the modification mechanism of polymers on concrete at micro-scale. But at nano-scale, the interaction between polymers and cement is an ongoing work, researches show that it contains several aspects, i.e., chemical bonding, hydrogen bonding, van der Waals forces, etc. Different polymers may have different types of interactions with cement. Understanding these interactions is important to elucidate the relationship between the microstructure and macroscopic properties of polymer-modified cement-based materials. Molecular dynamics simulation has proved to be an effective method to study the interactions between inorganic-organic composites at this stage but has some limitations.
Evaluation of Strength and Modulus of Elasticity of Polymer-Modified Cement Concrete (PCC) Under Thermal Impact Within a Defined Service Temperature Range
Authors: Flohr Alexander , Rohde Catharina , Narayana Savitha Devarajamohalla , Osburg Andrea
Published: November 2024

Polymer-modified cement mortars (PCM) and concretes (PCC) are mainly used in concrete repair and restoration exhibiting improved durability, suitable chemical resistance, and beneficial adhesion strength compared to unmodified cementitious materials. Due to these favorable properties, the material is increasingly implemented in construction. Commonly, the modifiers applied to cementitious binders consist of thermoplastic polymers, which feature a change in the deformation behavior under the influence of different temperatures. Despite the distinct temperature-dependent properties of the polymers, the load-dependent deformation behavior of PCM and PCC was barely investigated within a service temperature range. To make statements about the effect of polymers on the load bearing and elastic deformation behavior of PCM and PCC, the engineering properties of the material have to be experimentally assessed under thermal conditioning. Accordingly, the compressive and flexural strength as well as dynamic and static modulus of elasticity of seven different PCM mixtures were characterized while the specimens were exposed to service temperatures of −20 ℃, 20 ℃, and 60 ℃. After the specimens were thermally conditioned in a climate chamber, the samples were transferred to the equally conditioned test machine and tested in the proposed temperature scope. The experimental results reveal influential changes in all tested mechanical attributes for the modified system within the applied service temperature range compared to an unmodified reference. This knowledge is essential to further investigate the temperature impact on the material and develop appropriate prediction models for the application of polymer-modified cementitious materials in construction and the integration in design guidelines.
Basic Study on Ultra Rapid Hardening Alkali Activated Material Using Sodium Orthosilicate
Authors: Yamada Hiroshi , Wakasugi Mikio , Kanda Toshiyuki , Seki Tomonori , Ichimiya Kazuo
Published: November 2024

For the purpose of developing a repair material that contributes to decarbonization, a basic study is conducted on an alkali activated material that does not require an alkaline solution. Thin study is characterized by the use of sodium orthosilicate as an alkaline source in order to achieve powder premixing, be ultra rapid hardening. Specifically, a basic study on ultra rapid hardening property and an improvement of the length change performance of the material using only ground granulated blast furnace slag were carried out. As a result, it was clarified that sufficient compressive strength at 3 h can be achieved by increasing the alkaline usage rate, and that the length change performance can be improved by using shrinkage reducing agents and expansive agents.
Testing the Performance of Vinyl Ester and Polyester Polymer Concrete Following Exposure to Artificially Induced Climatic Environments
Authors: Gulabbhai Dhruv Parbhoo , Kruger Deon , Hira Mayur Kishor
Published: November 2024

The exposure of polymer concrete to artificially designed environmental conditions of high-and low-temperatures, and moisture levels allowed for the assessment of strength performance and aesthetic value. Strength performance indicated the maximum capability of the product to carry a load successfully, whereas the aesthetics assessed the appearance of the product, that can be measured using spectrophotometry. In this study, materials such as water and Portland cement typically used to form traditional concrete were replaced by two polymer resins namely - vinyl ester and polyester, thus making it polymer concrete. As such, compressive strengths of cube samples were tested, the change in cubes’ masses was measured using a balance - prior and post exposure to the artificially induced environments, the colour change tests (spectroscopy analysis) were performed using the spectrophotometer tests. Compressive strengths of over 75MPa were achieved, thereby justifying promising concrete strengths. Mass losses recorded were almost negligible, thereby showing toughness to conditions presented in the artificially induced environments. Minor colour changes were noticed- thereby showing a good resistance to harsh weather conditions on the surface properties. Therefore, the assessed products displayed desired characteristics for strength performance and aesthetic value, subsequently, creating a product that promotes sustainability.
Improvement of the Thermal Shock Resistance of Epoxy Resin Coating Using Sedimented Recycled Fine Aggregate
Authors: Krzywiński Kamil , Sadowski Łukasz
Published: November 2024

The floors made of epoxy resin coating that are exposed to the thermal loads are usually not durable enough to be used in industrial facilities. To enhance thermal properties of the coating recycled fine aggregate was used to reduce thermal expansions in the interphase zone in between the coating and substrate. Three different types of coating were analyzed: pure epoxy, specially homogenous, and functionally graded material. The top floor was loaded with temperature to obtain heat flux and strain results. Finite element method was used to simulate the heat transfer and heat load. Simulations show that sedimentation of the aggregate reduces heat flow to the substrate during loading. It means that properly designed aggregate can improve durability of the industrial floor which can be more resistance to thermal gradient.
The Effects of Modified Andreassen Particle-Packing Model on Polymer Modified Self-Leveling Heavy-Weight Mortar
Authors: Erüz A. Orhun , Özkul M. Hulusi , Akalın Özlem , Maraşlı Muhammed
Published: November 2024

Heavy-weight concretes are known for their high unit weight inherited from the aggregates and developed mainly for radiation shielding. Therefore, minimal porosity besides the high unit weight is a desired property. Numerous particle-packing theories were put forward to decrease the porosity by an ideal reference curve; modified Andreassen model based on the size distribution of ingredients to adjust the fineness. This research investigates the effect of the mentioned method on heavy-weight mortars. Cement, micro and nano silica combinations, and their polymer additive mixtures were used as binders in the specimens, along with barite and finely ground magnetite aggregates. In this work, the aggregate size limit selected 3 mm and the fineness factor of q was chosen as 0.22 and 0.25, depending on the mixture. To achieve a self-levelling consistency, the w/c ratio was kept constant at 0.40, and a superplasticizer was added to maintain the workability. Consecutively, the specimens were examined for unit weight, compressive strength, and capillary water absorption. The collected results were analyzed, and the difference between groups was compared according to their composition.
Current Status of Resin Concrete in Japan
Authors: Kai Nobuhiro , Kawakami Makoto , Kido Masahisa , Ishitsuka Kei , Kuwahara Yuki
Published: November 2024

Resin concrete, which has high strength, high early strength development and excellent chemical resistance, has been widely applied for repair and reinforcement of concrete structures, and precast products since the 1950’s. The research and development of resin concrete in Japan have evolved in tandem with various regions and international activities. It is a common and indispensable material for infrastructures in the world at present. On the other hand, there are so many different Acts of God, such as earthquakes, typhoons, and torrential rains, that occur in Japan, and disaster measures are an important issue. In this paper, the current status and practical application of resin concrete mainly applied for sewage products in Japan were investigated and discussed. Based on the regional characteristics of Japan, a resin concrete manhole of high quality to compensate for the defects of cement concrete was developed. Furthermore, the future trends in the research and development of resin concrete including environmental issues such as carbon dioxide emissions reduction, application of recycled materials and bioplastics to replace natural aggregates and petroleum-derived resin for concrete are proposed and discussed. A homogenization analysis method is introduced particularly to bring out the ability of resin concrete as composite materials and to carry out material development efficiently.
Recycled Mixed Plastic Fine Aggregate in Cement Concrete
Authors: Lee Kevin Jia , Wong Sook Fun
Published: November 2024

The literature extensively examines the utilization of sorted single-type plastic waste from post-consumer waste streams as a sustainable substitute for natural sand in cement concrete. However, severe heterogeneity of plastic waste in municipal solid waste streams, including variations in polymer types, grades, shapes, sizes, and cross-contamination with other commingled waste materials, poses a significant challenge in adopting findings from prior research that necessitates high-purity single-type plastic waste for concrete applications. This paper reports the characterization of cement concrete incorporated with mixed plastic fine aggregate (rMPFA) containing an optimized blend of plastic types produced using a proprietary mixed plastic recycling process. Five concrete mixtures containing 0% (M0), 10% (M10), 20% (M20), 30% (M30), and 40% (M40) rMPFA by volume of natural sand were investigated in this study. The laboratory results show that concrete mixture M20 had comparable compressive strength and water penetration test results when compared to control mixture M0. Additionally, toxicity characterization of concrete mixture M20 demonstrated a reduction of heavy metals in the leachate solution when compared to control mixture M0. Furthermore, microplastic detection analysis results of concrete mixtures M0 and M20 were comparable and stable.
Symposium—Towards Innovative Practices in Mathematics Education: Teachers’ and Students’ Choice and Use of Digital Resources
Authors: Pepin Birgit , Rezat Sebastian
Published: November 2024

In this symposium we investigate students’ agency of selecting and using (digital) resources for developing their own learning paths. For that, we first review the literature related to students’ selection and use of resources in mathematics education in different pedagogical settings (presentation 1). Second, we develop insights from the different studies that participate in this symposium (presentation 2–6), at school as well as at university level. Results show that attempts have been made to provide students opportunities to develop agency of their mathematics learning, in particular with the development and provision of numerous digital tools and learning resources at university level and related to innovative pedagogical approaches. At the same time, it is not obvious how these tools and resources help students to develop deeper conceptual understandings. Certainly, students often ‘demand’ more student-centered and autonomous education approaches (e.g., at university level), also in mathematics education. Further, it seems that authentic problem-based education approaches are more motivating for students. These ‘innovative’ approaches necessitate particular types of structure and support for students. Moreover, they require different ways of providing resources that students can and want to interact with, and that help students to navigate through the curriculum to develop their own learning paths. At the same time, teachers also need support on how to orchestrate student learning with the available resources in such environments, so to be able to attend to students’ individual needs. The symposium comprised altogether six presentations:

Birgit Pepin & Sebastian Rezat: Students’ agency of selecting and using (digital) resources for developing their own learning paths: An overview

Annalisa Cusi & Agnese I. Telloni: Learning through digital curriculum resource design: students’ reflections on their role as designers

Vilma Mesa, Lelia Burley-Sanford, Xinyi Hao, & Carlos Quiroz: Interactive features in university textbooks and their use by teachers and students

Sebastian Rezat: Fostering university students’ reading and understanding of mathematical text in a flipped classroom approach with a digital marking tool

Birgit Pepin & Ulises Salinas: Challenge/problem-based mathematics learning at university level: The case of the modeling week

Farzad Radmehr: Problem-posing: An inclusive activity for improving teaching and learning of mathematics at university level
Learning Through Digital Curriculum Resource Design: Students’ Reflections on Their Role as Designers
Authors: Cusi Annalisa , Telloni Agnese I.
Published: November 2024

The focus of this contribution is on the role that students could play as designers of digital curriculum resources (DCR) (Pepin et al., 2017). Our study focuses on data collected within an educational programme that involved 7 upper secondary school students (grade 12).
Research on the Quality Monitoring and Evaluation Index of Mathematics Textbooks in Basic Education
Authors: Kong Fanzhe , Zhao Xinyi
Published: November 2024

The construction of evaluation criteria is an important grip for the quality assurance system of textbooks. Major countries around the world have strategically reviewed and strengthened the construction and development of textbooks and made efforts to improve the quality of teaching materials. In particular, continuously increased the development and improvement of textbooks management methods, quality standards, and evaluation criteria, and have developed characteristics in terms of the basis for the development of textbooks evaluation criteria, evaluation content dimensions and specific indicators, evaluation methods and tools, etc. Analyzing the characteristics of the evaluation standards of textbooks in the world's major countries and learning from the experience of the management of textbooks in developed countries will help improve the quality standards of basic education textbooks in China and strengthen and improve the development, management, and construction of teaching materials in China.
Comparative Study of the Content of Quadrilateral in the Three Editions of Junior High School Mathematics Textbook
Authors: Chen Zhihao , Cheng Yi
Published: November 2024

“Quadrilaterals” is an important branch of mathematics in junior middle school. This study used qualitative and quantitative research methods to analyze and compare the “Quadrilaterals” content in Chinese and American Mathematics Textbooks from the macro layout structure design and micro content difficulty. It is concluded that the arrangement order of “Quadrilaterals” chapters in the three editions of textbooks is basically the same, the GMH version has a wide range of content, while the BNUP version has a low depth of content. The discuss of this study are as follows: properly add the expansion chapters of teaching materials, appropriately enrich the teaching introduction links, optimize the course structure and tap the beauty of mathematics.
Analysis of Higher-Order Thinking Skills Content in Chinese High School Mathematics Textbook
Authors: Huang Guihua , Han Wenying , Liu Yiyao
Published: November 2024

This study is a case study with quantitative analysis methods. It aims to explore the proportion of contents for HOTS within Chinese mathematical textbooks.The study defined HOTS in mathematics and provided an assessment framework based on the revised Bloom's taxonomy. The assessment framework was then used to categorize all exercise questions in the Chinese senior high school mathematics textbook. The instrument content validity was obtained through the focus group discussion forum, and the Delphi technique. The result shows that HOTS accounts for 48.18%, dominated by questions classified as analyzing (C1) totaling around 40.08%, there are still a few questions classified as evaluating (C2) of around 6.48% or creating (C3) around 1.62%, which reflects China's emphasis on cultivating students’ HOTS.
A Study on the Value Orientation of Chinese Excellent Traditional Culture Contents in Mathematics Textbooks: Based on the Analysis of the Primary School Mathematics Textbooks Published by PEP
Authors: Li Wanyue , Zhang Weizhong
Published: November 2024

The integration of Chinese excellent traditional culture into mathematics textbooks is an important measure to realize the fundamental task of moral education. Through the analysis of the excellent traditional Chinese culture content and its value orientation in the fourth grade mathematics textbooks of The People’s Education Press, it is found that the selection of cultural content is diversified, especially focus of state level of culture. The value structure of cultural education is complete, highlighting patriotism and concerns about science and culture; The teaching value of culture emphasizes on promoting problem raising, problem solving and deeper understanding through examples and cultural situations. There are various forms of cultural integration and its depth needs to be strengthened. The integration of Chinese excellent traditional culture into future mathematics textbooks can be improved from the following aspects: rationally examining the educational value and teaching value of Chinese excellent traditional culture, and constructing the target system; Based on the essence of the value of Chinese excellent traditional culture, clear principles of the integration; Optimize the content composition of cultural choice, highlight the value inheritance power of mathematics textbooks; Adjust the form structure of integration.
A Comparative Study of the Contents of “Plural” in Chinese and Japanese High School Mathematics Courses
Authors: Li Baozhen , Zhang Lina
Published: November 2024

Select China taught A high school math teaching material with book research mathematics textbook edition of the "plural" content as the research object, from chapter theme page, knowledge structure, column. The results show that there is a close connection between old and new knowledge in the theme page of the textbook chapter, the column design structure is rich, the basic knowledge is emphasized and the content distribution is focused, and the difficulty of example exercises is relatively low. The theme page of the chapter focuses on the introduction of mathematical history, the column design is simple, the content of knowledge expansion is extensive and comprehensive, and the comprehensive difficulty of examples and exercises is high. On this basis, we get some enlightenment on the compilation of complex content in Chinese textbooks.
Opportunities to Learn Mathematical Modelling in NCM Primary Textbook: A Case Study of NCM Textbook for Grade 6
Authors: Wang Tian , Tian Yanyan , Yang Jiaxin , Liu Jian
Published: November 2024

Mathematical modelling has become an important part of mathematics curriculum standards in many countries and needs to be focused and developed in textbooks. In order to obtain specific details about mathematical modelling in the mathematics textbooks and compare mathematical modelling across Oriental and Western mathematics textbooks, this study provides a unified analytical framework to present mathematical modelling within textbooks. Meanwhile, this paper examined two volumes of New Century Mathematics textbooks based on this new framework and connected the results with prior research to discuss the features of Chinese textbooks design regarding to mathematical modelling. Moreover, this framework could also be applicable to examine mathematical modelling in the textbooks in the future studies.
A Study on Learning Progression of Mathematics Teaching Material with Big Idea—Take Probability as an Example
Authors: Meng Hui , Wu Hua
Published: November 2024

The curriculum standard for general high school in China puts forward the concept of subject as the core to promote the cultivation of students’ core literacy. The mathematics teaching material is developed with a “big idea”, and learning progression is based on the “big perspective” of students’ cognitive development to complete the teaching structure. Taking the probability theme of mathematics material of the PEP edition as an example, this paper analyzes the material thoroughly, extracts the conceptual hierarchy, and constructs the learning progression model based on Jones's theory, to accurately grasp the changes in students’ learning to think.
A Comparative Analysis of the Time Content in Textbooks from Eight Countries
Authors: Sun Xinghua , Wu Qian , Song Qianqian , Shi Yingwei
Published: November 2024

In this paper, we report on a comparison of the treatment of the time content in primary mathematics textbooks used in eight countries, involved China, Japan, South Korea, Singapore, France, Germany, Russia, and the United States. For this purpose, we develop and apply a framework to analyse the similarities and differences of the time content in textbooks, especially the distribution characteristics of time concepts at different cognitive stages and the involved sub-concepts. We find both similarities and differences co-exist in the arrangement structure and grade distribution among these textbooks. We also draw on the results and our analysis to provide suggestions and directions for future textbook compiling about the time content.
Giving a Boost to Textbook Tasks
Authors: Van den Heuvel-Panhuizen Marja , Madsen Dag Oskar , Alstad Monica , Breckan Ruth-Amalie , Johansen Anne Marthe
Published: November 2024

Despite the generally acknowledged relevance of providing students with rich, challenging tasks that require genuine problem solving, several studies have shown that these tasks are often lacking in textbooks. Bringing new textbooks to the market might feel as a logical solution for this, but maybe there is also another way of resolving this problem in which teachers can also play a pivotal role: Enriching textbook tasks. In this paper we report about a case study carried out in a Norwegian fifth-grade classroom in which we explored Denisse Thompson’s suggestion (2012) to make textbooks richer by modifying existing textbook exercises. The focus in our study is on multi-digit algorithmic subtraction. The analysis of the students’ worksheets shows some interesting differences between the original and the enriched tasks.
Research on the Consistency Between Contents of Probability and Statistics of Compulsory Mathematics Textbook for Senior High School of Hunan Version and Curriculum Standards
Authors: Wang Jie , Lv Shihu
Published: November 2024

This paper uses the methods of content analysis, data statistics and comparative analysis, a “Survey of the Enacted Curriculum Model” is adopted to conduct consistency analysis from two dimensions: content subject and level (cognitive and process). The results show that body content of textbook and the Curriculum Standard have the strongest consistency in Comprehensive Level; textbook exercises and the Curriculum Standard have the strongest consistency in Mastery Level; the consistency between the body content of textbooks and the curriculum standard is basically the same at the level of Exploration and Experience.
An Empirical Study on Fifth Grade Students Using Statistical Model to Solve Practical Problems
Authors: Xie Qinnan , Zhang Qinqiong
Published: November 2024

Statistical model is one of the mathematical models. Knowing which statistical models students will use in solving problems and their level is helpful to cultivate students’ statistical modelling capability. This study is based on the New Century Mathematics (NCM), one of the mainstream textbooks in China. Taking the unit “Fallen Leaves on Campus” in the field of synthesis and practical teaching in Grade 5 as an example, by means of the method of personal interview, it is found that students will utilize descriptive models and inferential models when solving the tasks of “calculating the area of a fallen leaf” and “counting the number of leaves of a tree”. And it is also found that students have shortage in the awareness of selecting representative data and difficulties in solving the problem of “counting the number of leaves of a tree”. Therefore, this paper put forward two suggestions for the compilation of the content of “Synthesis and Practice” in mathematics teaching materials: first, more activities and opportunities for students to choose appropriate data can be added in the compilation of teaching materials; second, it is required to consider whether students can really complete the tasks in the textbook.
Textbook Analysis Framework and Case Analysis Pointing to Mathematical Modeling Literacy—Taking the Version of Hunan Education Press’ “Mathematical Modeling” as an Example
Authors: Zhang Bin , Qi Chunxia
Published: November 2024

Mathematical modeling is the basic means to solve practical problems, and also an important component of the core quality of mathematics. High school mathematics textbooks pay close attention to the implementation of mathematical modeling activities and mathematical inquiry activities. The article makes an in-depth analysis of the content of the teaching material from two aspects of mathematical modeling knowledge and mathematical modeling topics, and proposes that the arrangement of mathematical modeling content can effectively implement the requirements of the requirements of the new high school curriculum standard for mathematical modeling activities, and suggests that the “1+1” mode should be adopted to coordinate with the scientific evaluation, and the implementation of the normal course and special course teaching of mathematical modeling.
Cosmological collider non-Gaussianity from multiple scalars and R2 gravity
Authors: Aoki Shuntaro , Ghoshal Anish , Strumia Alessandro
Published: November 2024

Abstract

Cosmological collider signals of primordial non-Gaussianity arise at tree level when an extra scalar has Hubble mass during inflation. We critically review the formalism finding that a large class of inflationary theories, based on Planck-scale physics, predict a scalar bi-spectrum around the gravitational floor level. This mild signal arises for example in R2 gravity, in the regime where its gravitational scalar has Hubble-scale mass. Signals much above the gravitational floor arise in theories where scalars undergo multiple turns during inflation, thanks to sub-Planckian physics.
Large landscape of 4d superconformal field theories from small gauge theories
Authors: Cho Minseok , Maruyoshi Kazunobu , Nardoni Emily , Song Jaewon
Published: November 2024

Abstract

We systematically explore the space of renormalization group flows of four-dimensional $$ \mathcal{N} $$
N
= 1 superconformal field theories (SCFTs) triggered by relevant deformations, as well as by coupling to free chiral multiplets with relevant operators. In this way, we classify all possible fixed point SCFTs that can be obtained from certain rank 1 and 2 supersymmetric gauge theories with small amount of matter multiplets, identifying 7,346 inequivalent fixed points which pass a series of non-trivial consistency checks. This set of fixed points exhibits interesting statistical behaviors, including a narrow distribution of central charges (a, c), a correlation between the number of relevant operators and the ratio a/c, and trends in the lightest operator dimension versus a/c. The ratio a/c of this set is distributed between 0.7228 and 1.2100, where the upper bound is larger than that of previously known interacting SCFTs. Moreover, we find a plethora of highly non-perturbative phenomena, such as (super)symmetry enhancements, operator decoupling, non-commuting renormalization group flows, and dualities. We especially identify amongst these fixed points a new SCFT that has smaller central charges $$ \left(a,c\right)=\left(\frac{633}{2000},\frac{683}{2000}\right) $$

a
c

=

633
2000

683
2000

than that of the deformed minimal Argyres-Douglas theory, as well as novel Lagrangian duals for certain $$ \mathcal{N} $$
N
= 1 deformed Argyres-Douglas theories. We provide a website https://qft.kaist.ac.kr/landscape to navigate through our set of fixed points.
Strings near black holes are Carrollian. Part II
Authors: Bagchi Arjun , Banerjee Aritra , Hartong Jelle , Have Emil , Kolekar Kedar S.
Published: November 2024

Abstract

We study classical closed bosonic strings probing the near-horizon region of a non-extremal black hole and show that this corresponds to understanding string theory in the Carroll regime. This is done by first performing a Carroll expansion and then a near-horizon expansion of a closed relativistic string, subsequently showing that they agree. Concretely, we expand the phase space action in powers of c2, where c is the speed of light, assuming that the target space admits a string Carroll expansion (where two directions are singled out) and show that there exist two different Carroll strings: a magnetic and an electric string. The magnetic string has a Lorentzian worldsheet, whereas the worldsheet of the electric string is Carrollian. The geometry near the horizon of a four-dimensional (4D) Schwarzschild black hole takes the form of a string Carroll expansion (a 2D Rindler space fibred over a 2-sphere). We show that the solution space of relativistic strings near the horizon bifurcates and the two sectors precisely match with the magnetic/electric Carroll strings with an appropriate target space. Magnetic Carroll strings near a black hole shrink to a point on the two-sphere and either follow null geodesics or turn into folded strings on the 2D Rindler spacetime. Electric Carroll strings wrap the two-sphere and follow a massive geodesic in the Rindler space. Finally, we show that 4D non-extremal Kerr and Reissner-Nordström black holes also admit string Carroll expansions near their outer horizons, indicating that our formulation extends to generic non-extremal black holes.
Chiral separation effect from holographic QCD
Authors: Gallegos Domingo , Järvinen Matti , Weitz Eamonn
Published: November 2024

Abstract

We analyze the chiral separation effect (CSE) in QCD by using the gauge/gravity duality. In QCD, this effect arises from a combination of chiral anomalies and the axial U(1) anomaly. Due to the axial gluon anomaly, the value of the CSE conductivity is not determined by the anomalies of QCD but receives radiative corrections, which leads to nontrivial dependence on temperature and density. To analyze this dependence, we use different variants of the V-QCD, a complex holographic model, carefully fitted to QCD data. We find our results for the anomalous CSE conductivity at small chemical potential and nonzero temperature to be in good qualitative agreement with recent results from lattice QCD simulations. We furthermore give predictions for the behavior of the conductivity at finite (vectorial and axial) chemical potentials.
Soft theorems in matrix theory
Authors: Herderschee Aidan , Maldacena Juan
Published: November 2024

Abstract

We show that the Banks-Fischler-Shenker-Susskind matrix model for M-theory obeys the leading and subleading soft theorems expected from eleven-dimensional supergravity. The subleading soft theorem implies the amplitude is Lorentz symmetric. This is argued for general four point amplitudes, but only for restricted kinematics for five and higher point amplitudes.
Sexualität und Krebs bei Frauen
Authors: Hofmann Konstantin , Hasenburg Annette
Published: November 2024

Sexualität kann das Krebsrisiko durch sexuell übertragbare Infektionen wie HPV (humane Papillomviren), HIV (humanes Immundefizienzvirus) oder Hepatitisviren, aber auch Lebensstilfaktoren beeinflussen. Präventive Maßnahmen, wie beispielsweise HPV-Impfungen und ein verantwortungsbewusstes Sexualverhalten, senken das Krebsrisiko. Eine Krebsdiagnose und die damit verbundenen Therapien können zu sexuellen Funktionsstörungen führen. Über 60 % der krebskranken Frauen und 40 % der Männer leiden unter sexuellen Funktionsstörungen. Eine offene Kommunikation und eine interdisziplinäre Behandlung sind entscheidend, um die Patient:innen umfassend zu unterstützen und sexuelle Funktionsstörungen gezielt zu behandeln.
Kiselman minimum principle and rooftop envelopes in complex Hessian equations
Authors: Åhag Per , Czyż Rafał , Lu Chinh H. , Rashkovskii Alexander
Published: November 2024

We initiate the study of m-subharmonic functions with respect to a semipositive (1, 1)-form in Euclidean domains, providing a significant element in understanding geodesics within the context of complex Hessian equations. Based on the foundational Perron envelope construction, we prove a decomposition of m-subharmonic solutions, and a general comparison principle that effectively manages singular Hessian measures. Additionally, we establish a rooftop equality and an analogue of the Kiselman minimum principle, which are crucial ingredients in establishing a criterion for geodesic connectivity among m-subharmonic functions, expressed in terms of their asymptotic envelopes.
Automated assessment of brain MRIs in multiple sclerosis patients significantly reduces reading time
Authors: Sieber Victoria , Rusche Thilo , Yang Shan , Stieltjes Bram , Fischer Urs , Trebeschi Stefano , Cattin Philippe , Nguyen-Kim Dan Linh , Psychogios Marios-Nikos , Lieb Johanna M. , Sporns Peter B.
Published: November 2024

Introduction

Assessment of multiple sclerosis (MS) lesions on magnetic resonance imaging (MRI) is tedious, time-consuming, and error-prone. We evaluate whether assessment of new, expanding, and contrast-enhancing MS lesions can be done more time-efficiently by radiologists with assistance of artificial intelligence (AI).

Methods

Baseline and three follow-up (FU) MRIs of thirty-five consecutive patients diagnosed with MS were assessed by a radiologist manually, and with assistance of an AI-tool. Results were discussed with a consultant neuroradiologist and time metrics were evaluated.

Results

The mean reading time for the resident radiologist was 9.05 min (95CI: 6.85–11:25). With AI-assistance, the reading time was reduced by 2.83 min (95CI: 3.28–2.41, p < 0.001). The reading decreased steadily from baseline to FU3 for the resident radiologist (9.85 min baseline, 9.21 FU1, 8.64 FU2 and 8.44 FU3, p < 0.001). Assistance of AI further remarkably decreased reading times during follow-ups (3.29 min FU1, 3.92 FU2, 3.79 FU3, p < 0.001) but not at baseline (0.26 min, p = 0.96). The baseline reading time of the resident radiologist was 5.04 min (p < 0.001), with each lesion adding 0.14 min (p < 0.001). There was a substantial decrease in the baseline reading time from 5.04 min to 1.59 min (p = 0.23) with AI-assistance. Discussion of the reading results of the resident with the neuroradiology consultant (as usual in clinical routine) was exemplary done for FU-3 MRIs and added another 3 min (CI:2.27–3.76) to the reading time without AI-assistance.

Conclusion

We found that AI-assisted reading of MRIs of patients with MS may be faster than evaluating these MRIs without AI-assistance.