Flat Material Research Articles

Analisis Kemampuan Pemahaman dan Pemecahan Masalah pada Siswa Kelas VIII UPT SMP Negeri 27 Medan Terhadap Materi Bangun Datar dan Ruang

This study is a descriptive study with a qualitative approach that aims to analyze the errors made by students in solving mathematics problems, especially on flat and solid geometry materials using the Newman Theory approach. The subjects in this study were 30 seventh grade students at SMP Negeri 27 Medan. The method of collecting data or information was carried out through a written test of 3 (three) descriptive questions and interviews with selected subjects. The information obtained was then analyzed based on the Newman analysis procedure which is divided into 5 (five) stages of errors, namely reading, understanding, transformation, process skills, and writing answers. The results of the analysis showed that the most significant errors occurred at the transformation stage, with a percentage of 83.3%, categorized as very high. On the other hand, errors in process skills were classified as very low, namely 16.6%. This finding shows the importance of developing more effective learning methods to help students understand and solve mathematics problems, especially those related to geometric concepts.

Development of CABATAR Learning Media on Plane Geometry Material to Improve Numeracy Skills of 4th Grade Students at SDN Susukan 04 Pagi

This research develops the CABATAR learning media based on the Canva application to improve the numeracy skills of fourth-grade students on flat geometry material at SDN Susukan 04 Pagi. The research uses a Research and Development (R&D) approach, with both qualitative and quantitative methods. Data was collected through interviews, questionnaires, and validation by media and material experts. The study found that the CABATAR media was validated with 91.25% by media experts and 94.16% by material experts, both categorized as "Very Feasible." A small group of 10 students and a larger group of 31 students were involved in the trial, with student responses reaching an average of 90% and 89% from teachers, all categorized as "Very Feasible." Additionally, the pretest-posttest results showed a moderate improvement in numeracy skills, with an N-gain value of 0.62. The findings indicate that CABATAR media is an effective tool for enhancing numeracy skills in elementary school students and can be a valuable addition to flat geometry material in mathematics lessons.

Chebyshev Parameterization for Woven Fabric Modeling

Distortion-minimizing surface parameterization is an essential step for computing 2D pieces necessary to fabricate a target 3D shape from flat material. Garment design and textile fabrication are a prominent application example. Common distortion measures quantify length, angle or area preservation in an isotropic manner, so that when applied to woven textile fabrication, they implicitly assume fabric behaves like paper, which is inextensible in all directions and does not permit shearing. However, woven fabric differs significantly from paper: it exhibits anisotropy along the yarn directions and allows for some degree of shearing. We propose a novel distortion energy based on Chebyshev nets that anisotropically penalizes shearing and stretching. Our energy formulation can be used as an optimization objective for surface parameterization and is simple to minimize via a local-global algorithm. We demonstrate its advantages in modeling nets or woven fabric behavior over the commonly used isotropic distortion energies.

Prehistoric Cultural Migration in the Middle–Lower Lishui Catchment of Central China in Response to Environmental Changes

Climate change and geological shifts were pivotal in the survival and development of ancient human societies, especially in densely populated regions like the middle and lower Lishui River Basin. This study explored the dynamic interactions between ancient human cultures and the region’s natural environment, using field research alongside geological, geomorphological, and archaeological data spanning from the late Paleolithic to the Neolithic periods. Our findings showed that prehistoric sites in the middle and lower Lishui River Basin were primarily located in the low hilly areas surrounding the lower basin during the Paleolithic era, a pattern shaped by the region’s geomorphology. Early human settlements were strategically positioned near the Lishui River, offering access to vital resources while minimizing flood risk. These locations provided flat terrain, abundant vegetation, and materials for tool-making, factors that supported a hunting and gathering lifestyle. As the coldest phase of the last glacial period approached, the transition from the Paleolithic to the Neolithic eras marked a period of significant behavioral adaptation. In response to the harsher environment, humans began settling on lower terraces and miniaturizing their stone tools, signaling a shift to more specialized hunting techniques. This adaptability and resilience marked the refinement of hunting economies during this period. With the onset of the Holocene epoch and a warmer climate, conditions for human habitation became more favorable. Societies began migrating from the hills to the fertile lower Lishui River Basin, heralding the Neolithic period. This era saw the emergence of settlements and the onset of early rice cultivation, marking the transition from a hunting–gathering economy to one centered on agriculture. By the Daxi period, these settlements had expanded, extending their influence throughout the region. In conclusion, this study underscores the critical roles of climate change and geological features in shaping human settlement patterns, economic activities, and cultural evolution in the middle and lower Lishui River Basin. Our findings offer valuable insights into the evolutionary processes of ancient human cultures in the region and provide a foundation to understand future challenges in sustainable development.

Experimental and numerical investigation on ductile fracture of Q235 cold-formed thin-walled steel

In order to simulate the full-range moment-rotation characteristic of steel storage rack beam-to-upright connections incorporating material fracture, this paper presents experimental and numerical investigations into the fracture behaviour of Q235 cold-formed thin-walled steel (CFTWS) flat and corner materials. A total of 43 specimens derived from Q235 CFTWS plates were tested. Two different thicknesses (1.8 mm and 3.25 mm), three varied bend angles (0°, 70° and 90°), and five types of specimens representing different stress states, were considered. The load-displacement curves and fracture characteristics of each specimen were derived from tests. The refined numerical models were established and validated by the test data. Based on experimental and numerical simulation results, four commonly used ductile fracture models for metal materials were calibrated and compared. The results show that the verified LMVGM fracture model is applicable to Q235 CFTWS flat and corner materials, and then compiled into a USDFLD subroutine in numerical simulation models to predict the flexural behaviour of storage rack beam-to-upright connections. The comparison between test and numerical simulation results illustrates that the established ductile fracture model for Q235 CFTWS materials can accurately simulate the fracture related failure modes of beam-to-upright connections in CFTWS storage racks.

New three-dimensional flat band candidate materials Pb2As2O7 and Pb2Sn2O7

Energy dispersion of electrons is the most fundamental property of the solid state physics. In models of electrons on a lattice with strong geometric frustration, the band dispersion of electrons can disappear due to the quantum destructive interference of the wavefunction. This is called a flat band, and it is known to be the stage for the emergence of various fascinating physical properties. It is a challenging task to realize this flat band in a real material. 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These findings underscore the importance of investigating the influence of flat bands on electronic energy dispersion, providing a crucial step toward understanding the emergence and characteristics of flat bands in novel materials.

Upaya Meningkatkan Hasil Belajar Matematika Materi Bangun Datar dengan Pendekatan Matmatika Realistik di Kelas V SDN 101766 Bandar Setia

The purpose of this research is to see the results of learning mathematics on flat shapes material after using a realistic mathematics approach in class V of SD Negeri 101766 Bandar Setia. The research method used is Classroom Action Research (CAR). The CAR model used consists of 4 stages, namely planning, action, review (observation), and reflection. The subjects in this study were 22 students of class V-B of SD Negeri 101766 Bandar Setia, consisting of 10 male students and 12 female students. The data collection technique used in this study was observation and test analysis. The results of the study from the implementation of two cycles showed that the percentage of student learning activities increased by 60% in cycle I to 88.5% in cycle II. The percentage of student learning outcomes also increased from 59% (good) in cycle I to 86% (very good) in cycle II. Based on the results of the data analysis obtained, it can be concluded that the realistic mathematics approach can improve student learning outcomes in the mathematics subject of flat shapes material in class V of SD Negeri 101766 Bandar Setia

Applying heterogeneous building materials for the protection of people against electromagnetic radiation

The object of this study is the processes of shielding electromagnetic radiation by building and facing materials. The research is aimed at solving the problem of ensuring the electromagnetic safety of people by improving the composition and structures of building and facing materials. Means for improving the electromagnetic safety of people under industrial and domestic conditions using non-homogeneous building materials have been determined. The shielding properties of reinforced concrete structures were studied. A methodology for increasing their efficiency depending on the amplitude-frequency characteristics of the radiation that needs shielding has been devised. The efficiency of electromagnetic radiation shielding by heterogeneous dielectric building materials based on cement concrete and basalt fibers was determined. It was established that shielding through the refraction of electromagnetic waves on inhomogeneities does not give an acceptable effect. The expediency of covering basalt fibers with a conductive substance to increase the protective properties of materials was substantiated. The protective properties of flat facing material with carbonyl iron content were studied. It has been shown that the properties of materials can be effectively controlled by adjusting the filler. The material's transmission coefficient of ultra-high frequency electromagnetic radiation does not exceed 0.40, and the reflection coefficient – 0.25 with a filler content in the base of 14–15 % by volume. This makes it possible to simultaneously ensure the electromagnetic safety of people and the stable functioning of wireless communication devices. The advantage of the material is the low coefficients of reflection of electromagnetic waves, which does not lead to deterioration of the electromagnetic situation in other areas where people stay. It has been established that the addition of boron nitride to the facing material significantly increases the thermal insulation characteristics of the coating and contributes to the solution of energy saving problems. Adding a layer containing boron nitride to the material provides thermal conductivity coefficients of 0.030–0.031 W/m·K, which is better than known analogs

Kinetics of moisture exchange during convection drying of thin flat wet materials

The kinetics of convective drying of thin wet thermal insulation materials based on the relative drying rate and relative moisture contents has been studied. Processing of experimental data on drying of various wet materials has established that the relative drying rate is related to the relative moisture contents, which are the ratios of the current moisture content to its critical and initial values. Based on the functional dependence of the relative drying rate on the relative moisture contents using the processing of the experiment on drying of ceramics, felt, and asbestos, equations for calculating the drying time are obtained. The dependence of the relative drying rate on the ratio of the current moisture content to the critical one is given. Zonal methods for calculating the drying time are given, based on the drying rate curve. An expression for determining the drying coefficient is developed. Based on the analysis of experimental data on drying porous ceramics, sheet asbestos, and wool felt, graphs of the dependence of the relative drying rate on the ratio of the current moisture content to the initial one are constructed. Dependencies for determining the critical moisture content of the material are given. The considered method of processing experimental data allows obtaining all the main equations for calculating the kinetics of the drying process. A variant of estimating the drying time based on one experiment with a short time interval is given. A comparison of the calculated values according to the equations with the experiment is performed. The spread of the calculated values is in the range of experimental error. The formulas for calculating the drying time obtained without plotting the drying rate curve allow significantly reducing the time of processing the experimental data and can be applied to other materials.

Методика обработки сигналов, позволяющая уменьшить погрешности измерений бистатических характеристик рассеяния образцов материалов

In this paper a signal processing technique for bistatic measurements of the reflection coefficient of flat material samples is presented. This technique is based on comparing the reflected signal from the object under study and the background signal in the time domain. The use of this technique makes it possible to increase the accuracy of measurements of the characteristics of bistatic scattering of objects with a small amplitude of the reflected wave. This technique allows us to offset for the measurement error caused by the inaccuracy of antenna positioning and significantly reduce the measurement error caused by the interaction of antennas with each other at large bistatic angles. The reflection coefficient of the material sample was measured. The obtained results were processed by vector subtraction, time domain and using the developed technique. It was shown that the use of this technique allows one to increase the accuracy of measuring the reflectance of the material. This technique reduces the error in determining the minimum value of the reflection coefficient and the angle at which this minimum is achieved. The most effective is to use background synthesis and time domain together.

PENGGUNAAN KERTAS ORIGAMI UNTUK MENINGKATKAN HASIL BELAJAR PADA MATERI BANGUN DATAR SISWA KELAS III SD

The study aims to determine the effectiveness of using origami paper in improving the learning achievement of grade III elementary school students. The research method used is classroom action research (CAR) which is carried out in two cycles. Data collection is carried out through observation sheets and comprehension tests. The results of the study found that although the average academic achievement of students in the "very good" category in cycle I with an average of 80.9, there were still 10 students who were not fully academically capable. After improvements were made in cycle II, the average score of students in the special category increased significantly to 93.1 with all students achieving completion. Based on the results of the study, it was concluded that the use of origami as a learning medium effectively improves the learning outcomes of Mathematics in flat geometry material for grade III students. Origami media can express abstract Mathematical concepts so that they are easier for students to understand. In addition, the use of origami supports increases student involvement and enthusiasm in learning.

Self-Assembly of Soft and Conformable Broadband Absorbing Nanocellulose-Gold Nanoparticle Composites.

Broadband light-absorbing materials are of large interest for numerous applications ranging from solar harvesting and photocatalysis to low reflection coatings. Fabrication of these materials is often complex and typically utilizes coating techniques optimized for flat and hard materials. Here, we show a self-assembly based strategy for generating robust but mechanically flexible broadband light-absorbing soft materials that can conform to curved surfaces and surface irregularities. The materials were fabricated by adsorbing large quantities of gold nanoparticles (AuNPs) on the nanofibrils of hydrated bacterial cellulose (BC) membranes by tailoring the interaction potential between the cellulose nanofibrils and the AuNPs. The highly efficient self-assembly process resulted in very dense multilayers of AuNPs on the nanofibrils, causing extensive broadening of the localized surface plasmon resonance band and a striking black appearance of the BC membranes. The nanocomposite materials showed an absorptance >96% in both the visible and the near-infrared wavelength range. The AuNP-functionalized BC membranes demonstrated excellent conformability to curved and structured surfaces and could adopt the shape of highly irregular surface structures without any obvious changes in their optical properties. The proposed self-assembly based strategy enables the fabrication of soft and conformable broadband light-absorbing nanocomposites with unique optical and mechanical properties using sustainable cellulose-based materials.

Pengembangan Media Flat Math Bebasis Etnomatematika pada Materi Bangun Datar di Sekolah Dasar

This research is based on the development of 21st century learning, where PowerPoint is one of the applications that support learning with attractive designs. This research is a type of R&D development research with the ADDIE model as the development model. The research population was class II students, with a sample of 10 students from SDN Gempolkerep. The data analysis technique used is the Likert Scale. Flat shape material is introduced at the low grade level, and in this product, the material is associated with local culture, especially the culture in Mojokerto, East Java, which is adjacent to this research area. The results showed that the interactive Flat Math media had been tested for its feasibility and declared fit for use. The validation results of media experts get a percentage of 75% which indicates eligibility, while the results of the validation of material experts get a percentage of 86% which indicates very feasible qualifications. Linguist validation also shows decent results with a percentage of 76%. The average questionnaire results from student respondents show a percentage of 80.4% which indicates that this media is very feasible to use. In addition, the teacher's assessment also gave a percentage of 82%. Based on the data analysis, it can be concluded that Flat Math interactive media is appropriate for use in supporting learning in flat shape material.

The Effect of Using Powerpoint Media on The Ability to Solve Mathematical Problems of Flat Shapes

This study aims to determine the effect of using Powerpoint media on the ability of fourth-grade students of SDN 2 Singocandi to solve mathematical problems based on Polya's theory. Based on the results of tests and interviews, it appears that student's ability to solve mathematical problems is still lacking. This research uses quantitative methods with a survey research type. The population in this study were fourth-grade students of SDN 2 Singocandi. The sample taken in this study was all students totaling 20 students. The sampling technique was carried out using a saturated sampling technique which was. Data collection techniques included written tests, interviews, and documentation. This research design is pre-test and post-test. The analysis technique used is the paired sample t-test analysis technique. The results showed that the use of PowerPoint learning media affected the skills of solving mathematical problems on flat material, which was categorized as (1) Students in the high category who can solve problems understand, plan, implement, and check answers by Polya's steps. (2) Students in the medium category can understand the problem, make a solution plan, and implement the plan, but do not check the answer. (3) Students in the low category were unable to solve the problem according to the steps of Polya's theory.

Superlubric Graphullerene.

Graphullerene (GF), an extended quasi-two-dimensional network of C60 molecules, is proposed as a multicontact platform for constructing superlubric interfaces with layered materials. Such interfaces are predicted to present very small and comparable sliding energy corrugation regardless of the identity of the underlying flat layered material surface. It is shown that, beyond the geometrical effect, covalent interlinking between the C60 molecules results in reduction of the sliding energy barrier. For extended GF supercells, negligible sliding energy barriers are found along all sliding directions considered, even when compared to the case of the robust superlubric graphene/h-BN heterojunction. This suggests that multicontact architectures can be used to design ultrasuperlubric interfaces, where superlubricity may persist under extreme sliding conditions.

PENGEMBANGAN MEDIA PEMBELAJARAN BERBASIS ISPRING SUITE PADA MATERI BANGUN RUANG SISI DATAR

This research aims to develop ispring suite-based learning media on flat side space building materials reviewed from the aspects of feasibility, practicality and effectiveness. The research uses the R&D method, namely (Research and Development), and uses the ADDIE learning design model (Analysis, Design, Development, Implementation and Evaluation). The media developed uses ispring suite software, which is software used to create interactive learning media in the form of material presentations, material videos, practice questions, and quizzes. The test subjects in this study used individual and small group trials. The individual trial was 3 students of class VIII Madrasah Tsanawiyah and for the small group trial, namely 13 students of class VIII Madrasah Tsanawiyah. The results of this study, according to the assessment of media experts and material experts, show that ispring suite-based learning media obtained criteria suitable for use with an average score of 4.1. The results of the trials conducted on individual trials and small group trials showed that the ispring suite-based learning media obtained very practical criteria with an average score of 4.3. The ispring suite-based learning media also obtained very effective criteria with an average N-gain score of 0.87 based on the results of individual trial tests and small group trial test results.

Picture and Picture Learning Model in Improving Mathematics Learning Outcomes for Students at SDN Wonobodro 01 on Flat Shapes Matter

The problem in this research is that the learning outcomes of class II students at SDN Wonobodro 01 are still low in Mathematics on the topic of flat shapes. This is because the learning system provided by the teacher in class is less interesting, causing students to be less enthusiastic about participating in the learning provided. The aim of this research is to determine the increase in mathematics learning outcomes in flat shapes material using the picture and picture learning model for class II students in the first semester of SDN Wonobodro 01. The research method used is classroom action research (CAR) which is carried out in two cycles and every cycle consists of four stages, namely planning, implementation, observation and reflection. The research results showed that the picture and picture model was successful in improving student learning outcomes. This was shown by the results of the percentage of student completion in the pre-cycle of only 19.2% with an average class score of 53.1. Then, in cycle I it increased to 53.8% with an average class score of 64.8 and increased again in cycle II to 92.3% with an average class score of 90.7. Thus, it can be concluded that the use of the picture and picture model in the material for building mathematical data was successful because student learning outcomes increased each cycle.

Efficient nitrite determination by electrochemical approach in liquid phase with ultrasonically prepared gold-nanoparticle-conjugated conducting polymer nanocomposites.

An electrochemical nitrite sensor probe is introduced herein using a modified flat glassy carbon electrode (GCE) and SrTiO3 material doped with spherical-shaped gold nanoparticles (Au-NPs) and polypyrrole carbon (PPyC) at a pH of 7.0 in a phosphate buffer solution. The nanocomposites (NCs) containing Au-NPs, PPyC, and SrTiO3 were synthesized by ultrasonication, and their properties were thoroughly characterized through structural, elemental, optical, and morphological analyses with various conventional spectroscopic methods, such as field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller method. The peak currents due to nitrite oxidation were characterized in detail and analyzed using conventional cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV) under ambient conditions. The sensor response increased significantly from 0.15 to 1.5mM of nitrite ions, and the sensor was fabricated by coating a conducting agent (PEDOT:PSS) on the GCE to obtain the Au-NPs/PPyC/SrTiO3 NCs/PEDOT:PSS/GCE probe. The sensor's sensitivity was determined as 0.5μA/μM∙cm2 from the ratio of the slope of the linear detection range by considering the active surface area (0.0316cm2) of the flat GCE. In addition, the limit of detection was determined as 20.00 ± 1.00 µM, which was found to be satisfactory. The sensor's stability, pH optimization, and reliability were also evaluated in these analyses. Overall, the sensor results were found to be satisfactory. Real environmental samples were then analyzed to evaluate the sensor's reliability through DPV, and the results showed that the proposed novel electrochemical sensor holds great promise for mitigating water contamination in the real samples with the lab-made Au-NPs/PPyC/SrTiO3 NC. Thus, this study provides valuable insights for improving sensors for broad environmental monitoring applications using the electrochemical approach.

Lithium-modified B3C2P3 monolayer as a promising medium for reversible hydrogen storage

Although two-dimensional (2D) materials have been extensively studied as hydrogen storage media, the search for 2D materials with high hydrogen storage capacity and reversible hydrogen storage properties at room temperature remains challenging. In this context, B3C2P3 monolayer with Li modification is studied systematically by first-principles calculation. We find that Li-modified B3C2P3 monolayer can achieve a high hydrogen storage capacity of 8.99 wt% with an average adsorption energy of −0.23 eV/H2. Three of the H2 molecules are adsorbed around the Li atom, while the fourth H2 molecule is adsorbed above the buckled P atom due to the constricted space around the Li atom. Not only metal Li atoms but also the buckled substrate plays an important role in hydrogen adsorption, indicating that buckled 2D materials are more interesting and promising in hydrogen storage than flat 2D materials. The average desorption temperature (TD) calculated by van't Hoff formula is 293.84 K, which is very close to room temperature. In addition, at room temperature, the structure of hydrogen adsorption is stable at a low pressure of 3.21 MPa, suggesting a broad application prospect of in reversible hydrogen storage.

Penerapan Joyful Learning Dalam Upaya Peningkatan Minat dan Hasil Belajar Matematika

This research discusses the application of Joyful Learning which aims to determine students' interest and learning outcomes in mathematics on flat building material in class VII-5. The method used in this research is quantitative. The research instruments used are questionnaires in the form of observation sheets and Learner Worksheets. The data collection technique in this study consisted of conducting a test before the application of Joyful Learning (pre-test) and a test after Joyful Learning (posttest) in one class which became the research subject. Data analysis techniques used, namely validity and reliability tests, normality tests, Wilcoxon tests. The results of this research indicate that the application of the Joyful Learning model is proven to be able to increase student interest and learning outcomes. This is because the learning is fun and makes students play an active role in the learning process. Thus it can be concluded that the Joyful Learning model has a positive effect on student interest and student math learning outcomes on flat building material. Keywords: Joyful Learning, Learning Outcomes, Interest in Learning