PENGEMBANGAN LKPD Qr Code IPA PADA MATERI TUMBUHAN SUMBER KEHIDUPAN DI BUMI MATA PELAJARAN IPAS KELAS IV SD

Based on the results of the analysis of grade IV students, teachers do not use technology during learning so that the learning carried out in class is monotonous even though students are familiar with technology. This causes students to experience boredom and decreased interest in learning in science learning itself. Based on this, researchers developed the Development of Qr Code LKPD Science on the Material for the Growth of Life Resources on Earth Science Subjects Class IV Elementary School. The purpose of this research is to produce Qr Code LKPD Science products on the Growth of Life Resources on Earth Science Subjects Class IV Elementary School. This type of research uses the ADDIE model and consists of five stages, namely analysis, design, development, implementation, and evaluation. The data collection techniques used were observation, interviews, questionnaires, and documentation. Based on the results of mteri experts obtained a percentage of 94%. While the results of expert validation of teaching materials obtained a percentage of 100%. Based on the assessment of validators, material experts and teaching material experts, it can be concluded that the Qr Code LKPD Science is very feasible for use by grade IV elementary school students. When the Qr Code LKPD Science is implemented, students give a positive response to teaching materials such as being more active in learning, students are also active in doing questions and answers with the right answers, students are also more enthusiastic about learning using Qr Code LKPD Science. This is evident from the data obtained by researchers, namely from the questionnaire the response of students gets 92% results, while the teacher's response gets a percentage of 100%. In addition, media effectiveness tests were also carried out to see the improvement in student learning outcomes after using the Qr Code LPKD Science by obtaining a percentage of 84%, so that it can be concluded that the LKPD Qr Code Science is effective and feasible to be used in learning Science material Plant Source of Life on Earth

Scientific Instruments and Epistemology Engines

This article outlines the gradually changing attitude towards instruments and materials in the philosophy and historiography of science and confronts contemporary revaluations of the material culture of science with Hans-Jörg Rhein- berger's concept of an experimental system and Don Ihde's notion of an epistemology engine

Models and Simulations in Material Science: Two Cases Without Error Bars

We discuss two research projects in material science in which the results cannot be stated with an estimation of the error: a spectro- scopic ellipsometry study aimed at determining the orientation of DNA molecules on diamond and a scanning tunneling microscopy study of platinum-induced nanowires on germanium. To investigate the reliability of the results, we apply ideas from the philosophy of models in science. Even if the studies had reported an error value, the trustworthiness of the result would not depend on that value alone.Comment: 20 pages, 2 figure

Assessment of crystallographic influence on material properties of calcite brachiopods

Calcium carbonate biominerals are frequently analysed in materials science due to their abundance, diversity and unique material properties. Aragonite nacre is intensively studied, but less information is available about the material properties of biogenic calcite, despite its occurrence in a wide range of structures in different organisms. In particular, there is insufficient knowledge about how preferential crystallographic orientations influence these material properties. Here, we study the influence of crystallography on material properties in calcite semi-nacre and fibres of brachiopod shells using nano-indentation and electron backscatter diffraction (EBSD). The nano-indentation results show that calcite semi-nacre is a harder and stiffer (H {approx} 3–5 GPa; E = 50–85 GPa) biomineral structure than calcite fibres (H = 0.4–3 GPa; E = 30–60 GPa). The integration of EBSD to these studies has revealed a relationship between the crystallography and material properties at high spatial resolution for calcite semi-nacre. The presence of crystals with the c-axis perpendicular to the plane-of-view in longitudinal section increases hardness and stiffness. The present study determines how nano-indentation and EBSD can be combined to provide a detailed understanding of biomineral structures and their analysis for application in materials science

Design and optimization of a laser-PIXE beamline for material science applications

Multi-MeV proton beams can be generated by irradiating thin solid foils with ultra-intense (>10^18 W/cm^2) short laser pulses. Several of their characteristics, such as high bunch charge and short pulse duration, make them a complementary alternative to conventional radio frequency-based accelerators. A potential material science application is the chemical analysis of cultural heritage (CH) artifacts. The complete chemistry of the bulk material (ceramics, metals) can be retrieved through sophisticated nuclear techniques such as particle-induced X-ray emission (PIXE). Recently, the use of laser-generated proton beams was introduced as diagnostics in material science (laser-PIXE or laser-driven PIXE): Coupling laser-generated proton sources to conventional beam steering devices successfully enhances the capture and transport of the laser-accelerated beam. This leads to a reduction of the high divergence and broad energy spread at the source. The design of our hybrid beamline is composed of an energy selector, followed by permanent quadrupole magnets aiming for better control and manipulation of the final proton beam parameters. This allows tailoring both, mean proton energy and spot sizes, yet keeping the system compact. We performed a theoretical study optimizing a beamline for laser-PIXE applications. Our design enables monochromatizing the beam and shaping its final spot size. We obtain spot sizes ranging between a fraction of mm up to cm scale at a fraction of nC proton charge per shot. These results pave the way for a versatile and tunable laserPIXE at a multi-Hz repetition rate using modern commercially available laser systems