Flat Material Research Articles

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.

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.

Analisis Kesulitan Belajar Matematika Materi Bangun Datar Kelas IV SD 1 Gondosari

This study aims to analyze the learning difficulties of fourth grade students on flat building material at SD 1 Gondosari, Gebog, Kudus Regency. The method used is qualitative with a case study approach. Data were obtained through questionnaires and interviews involving students and teachers as research subjects. The results showed that students' learning difficulties were influenced by internal and external factors. Internal factors include negative attitudes towards mathematics, lack of understanding of concepts, difficulties in numeracy skills, and problem-solving ability. External factors include less than optimal use of learning media and lack of attention from parents. The findings show that students' main difficulties are in understanding the concept of the formula, calculating the square area, and solving varied problems. Therefore, it is important for teachers to understand students' development and use innovative learning media and involve parents in their children's learning process.

Finite Elastic Deformations of Initially Flat Thin Rubber-Like Materials

This contribution aims to derive a nonlinear FE formulation for large elastic deformation of hyperelastic thin rubber-like elastomeric materials. The formulation accounts for isotropic as well as transversely isotropic rubber-like materials. Besides, with the developed formulation, deformation of incompressible as well as compressible materials can be investigated. The formulation is applicable for in-plane and out-of-plane deformation of thin membranes. Several problems are inspected including uniaxial and equibiaxial extension of rubber, axisymmetric deformation of annular sheet, stretching a perforated rubber, extension of an anisotropic rubber, and inflation of an initially-flat circular and a square membrane. The results show very good agreement compared with those reported in the literature. Moreover, this model is able to model the inflation of initially flat membranes which is not possible to be done by commercial software.

MarBel Math: Android-Based Electronic Mathematics Book to Enhance Learning Outcomes for Fourth-Grade Students

The limitations in providing innovative learning media that align with the developments in Science and Technology negatively impact students, such as difficulty understanding the material, low learning motivation, and poor learning outcomes. This research aims to develop an Android-based electronic book learning media named MarBel Math for flat shapes material in the fourth grade of Elementary School. This research employs the Research and Development (R&D) method with the ADDIE development model, which consists of five stages: Analysis, Design, Development, Implementation, and Evaluation. Data collection techniques utilize both test and non-test methods. The data analysis technique involves both quantitative and qualitative data analysis methods. The validation results from content experts yielded an average score of 92%, classified as "very suitable," In the validation test by media experts, an average score of 85% was obtained, classified as "suitable". The study utilized t-test and n-gain analysis to assess the effectiveness of implementing MarBel Math learning media. This test revealed an average increase in student learning outcomes by 68%, with the average increasing from the initial or pre-test score of 54 to 85 in the post-test. From these results, MarBel Math learning media is considered to have very suitable qualifications for use in learning activities and is quite effective in improving student learning outcomes, especially in mathematics learning for flat shapes material in fourth-grade Elementary School.

Penerapan Model Pembelajaran Picture And Picture Untuk Meningkatkan Hasil Belajar Siswa Materi Bangun Datar Pelajaran Matematika Kelas I SD Alfityah Pekanbaru

The low learning outcomes of students in flat shapes material in grade 1 elementary school mathematics lessons is the main problem faced. Students often have difficulty understanding the basic concepts of flat shapes taught conventionally. The aim of the research is to improve student learning outcomes by using the Picture and Picture learning model for Flat Building Material in Mathematics Lessons. This research method includes Classroom Action Research (PTK) which was carried out in two cycles. Each cycle consists of four stages, namely design, implementation, observation and reflection. The research results obtained are (1) teacher activity in cycle I using the Picture and Picture learning model from 83.92% to 92.85% in the cycle II, (2) student activities in cycle I using the Picture and Picture model 75% to 91% in cycle II and (3) learning outcomes for Flat Figure material in Mathematics lessons in cycle I using the Picture and Picture model 60% to 90% in cycle II. This shows that the student learning outcomes for Mathematics Lesson Flat Figure Material using the Picture and Picture Learning model show very positive results.

Response properties of lattice metamaterials under periodically distributed boundary loads

We discuss response properties of lattice metamaterials to sinusoidal distributed static loads applied on a material edge. Analytical displacement solutions are obtained using a Fourier domain transfer matrix for both essential and natural boundary conditions, which are valid for a state of plane strain in orthorhombic lattices, as well as for planar metasurfaces. These solutions give sinusoidal displacement profiles in the material interior of the same wavenumber (spatial frequency) as the boundary load. Their amplitudes decay in the material interior in one of two possible ways, exponential or oscillatory exponential, depending on the lattice design and on the spatial frequency of the load. There is a tendency for the oscillatory exponential behavior to occur at lower wavenumbers representing smoother boundary loads. As explained on a specific example, comparing the metamaterial’s response amplitudes with those of a homogenous material also allows studying an effective, wavenumber-dependent shear modulus of the lattice, which can take both positive and negative values.

THE INFLUENCE OF TANGRAM MEDIA ON STUDENTS' INTEREST TO IMPROVE THE STUDENTS’ ENTHUSIASTISM IN LEARNING

This research was motivated by students' low interest in learning due to a lack of enthusiasm for learning in mathematics subjects, so that students were not interested in learning, liked to talk to friends, and did not pay attention to the teacher when teaching during the learning process. And also by using learning media that does not involve students in the teaching and learning process so that students are less enthusiastic in learning, not motivated because they are not involved in learning and causes students to be inactive during learning. This research aims to determine the influence of tangram media on students' interest in learning flat shape material in class IV at SD Negeri 30 Palembang. This research was carried out at SD Negeri 30 Palembang which is located on Jl. Freshwater River, 29 Ilir, Kec. Ilir Barat II, Palembang City, South Sumatra. This research is a type of experimental research, namely the True Experimental Design type. The population and sample in this research were fourth grade students at SD Negeri 30 Palembang, totaling 32 students in the control class and 32 students in the experimental class. Data collection techniques in this research are observation, questionnaires and documentation. Data analysis techniques in this research include Normality Test, Homogeneity Test, Hypothesis Test. The results of this research are hypothesis testing showing that t count ≥ t table or 6.938 ≥ 0.349, so it can be concluded that H0 is rejected and Ha is accepted. This means that there is an influence of tangram media on students' interest in learning flat shape material in class IV at SD Negeri 30 Palembang.

Teaching Materials Based on Ethnomathematics of Muaro Jambi Temple

The mathematics teaching materials teachers use are complex for students to understand, and there needs to be elements of cultural content. Based on this, this research aims to develop flat-building teaching materials based on the ethnomathematics of Muaro Jambi Temple. This type of research is development research using the ADDIE model (Analysis, Design, Development, Implementation, Evaluation). The methods used to collect data are observation, interviews, questionnaires, and tests. The instruments used to collect data were questionnaire sheets and test questions. The validation stage is divided into two stages: validation 1 by three experts (material, design, and language) and validation 2 by the teacher to see the practicality of the teaching materials. The data analysis technique uses qualitative and quantitative descriptive analysis. The research results showed that the validation of material experts with presentations was 83.5%, design experts 86.7%, and language experts 85.2%. The teacher's practicality test obtained 77%, and the student's response to the teaching materials obtained a presentation of 90%. The validation results show that the teaching materials developed are efficient in the mathematics learning process and meet valid and practical criteria. It was concluded that the Muaro Jambi Temple ethnomathematics-based flat building teaching materials were suitable for learning.

Innovative Learning Media: Ethnomathematics-based Modules for Third-Grade of Elementary School Students

Low learning outcomes on the properties of flat shapes for grade three elementary school students are indicated due to the unavailability of adequate modules. Meanwhile, third-grade students find it easier to learn math through cultural sites as a form of ethnomathematics. This study aims to develop an ethnomathematics-based module that is valid, practical, and effective in improving the learning outcomes of third-grade students on the material properties of flat shapes. This study uses the research and development method through the stages of analysis, design, development, implementation, and evaluation (ADDIE). The subjects of this study were 22 third-grade elementary school students. The validity of the module was measured through validator assessment using a validation questionnaire. The practicality of the module was measured using a student response questionnaire. Effectiveness was measured by comparing pre-test and post-test scores. Data collection techniques used questionnaires and tests. The validity results obtained an average value of 1 in the interval 0.80-1,00 with very valid criteria. Practicality obtained a value of 94% in the interval 85.01%-100% with very practical criteria. Effectiveness obtained a significance value of 0.000<0.05, which can improve student learning outcomes. Hence, the implication of the results of this development research is to provide a model or example of valid, practical, and effective ethnomathematics-based modules to improve the learning outcomes of third-grade students on the properties of flat shapes material.

Elementary teacher’s perspective critical thinking process in analyzing mathematics problems: Right triangles

In the learning process that occurs, many students work quickly, but the results obtained are not accurate. This is because students do not carry out the evaluation process. This research aims to analyze students’ critical thinking processes in solving mathematics problems. The questions discussed are flat geometry material, especially right triangles. The research method used is descriptive qualitative. The subjects were 13 students Elementary School Teacher, Faculty Teacher Training and Education, University Muhammadiyah of Malang. Subjects were selected using the purposive sampling method. The questions were given to 50 potential respondents and only 13 students were able to analyze them correctly. This research has resulted in 13 subjects being able to write information using their language at the interpretation stage. In the analysis stage, this subject can find the latest information by connecting previous knowledge with information obtained while studying in class. Evaluation Stage, 13 subjects were able to carry out the evaluation process by linking the main information found. In the interpretation stage, all subjects can draw a conclusion accompanied by reasons to support the answers and conclusions obtained. Communication and regulation stage, 13 subjects were able to communicate and carry out the process well.

Peningkatan Hasil Belajar Matematika melalui Penerapan Model Pembelajaran Accelerated Learning Tipe Message (Mindset, Entrance, Switch-Ownership, Store, Act, Go-again, Engage) pada Peserta Didik Kelas 5 SDN Dukuh Kupang V Surabaya

This research aims to improve mathematics learning outcomes in flat volume material through the application of the MESSAGE Type Accelerated Learning learning model (Mindset, Entrance, Switch-Ownership, Store, Act, Go-again, Engage) in grade 5 students at SDN Dukuh Kupang V Surabaya . The method used in this research is Classroom Action Research (PTK) which is carried out in two cycles, each consisting of planning, implementation, observation and reflection. The research results showed a significant increase in students' mathematics learning outcomes. In the pre-cycle, the percentage of student learning completion only reached 55%. After implementing the MESSAGE learning model in cycle I, the percentage of student learning completion increased to 70%. In cycle II, the percentage of student learning completeness further increased to 85%. This increase shows that the application of the MESSAGE Type Accelerated Learning learning model is effective in improving mathematics learning outcomes regarding volume of plane shapes in class 5 students. Based on the results of this research, it is concluded that the use of the MESSAGE learning model can increase student involvement and facilitate better understanding of concepts, thus having a positive impact on their mathematics learning outcomes. It is recommended for educators to consider using this model as an alternative in teaching mathematics.

The capability of diffuse coplanar surface barrier plasma to effectively remove contaminants from surfaces of various materials

AbstractUsing the fluorescence method, the study quantifies the cleaning efficiency of flat surfaces of selected materials (steel, polymethyl methacrylate, glass) compared to the usual cleaning methods: cleaning using ultrasound and cleaning using solutions (ethanol/isopropyl alcohol – isopropanol). Cleaning using ethanol/isopropanol solutions was carried out in such a way as to simulate common procedures: rubbing, rinsing and a combination of application of the solution and ultrasound. Based on the prepared and evaluated (following the average at several places on the surface) values of fluorescence maps of material surfaces, the resulting values of fluorescence before/after cleaning or at the selected moment of degreasing/cleaning of surfaces (applies to steel) were determined. The application of diffuse coplanar surface barrier discharge plasma discharge to the surfaces of flat materials can provide: a reduction in the environmental burden (no chemicals are needed to clean the surfaces) and an improvement in the efficiency of surface cleaning in industrial/manufacturing conditions (plasma cleaning usually takes a few seconds). diffuse coplanar surface barrier discharge plasma can clean and simultaneously activate the surfaces of flat materials.