Penerapan Metode Multistrategi Sebagai Upaya dalam Meningkatkan Aktivitas dan Hasil Belajar Siswa terhadap Pembelajaran Teks Proposal

This study aims to increase the activity and results of learning Indonesian during the Covid-19 pandemic through a multi-strategic method in class XI MIPA 2 students of SMA Negeri 2 Soppeng. The research conducted was a classroom action research regarding the application of multi-strategic methods that aimed to increase student learning activities and outcomes in learning proposal texts at SMA Negeri 2 Soppeng, Soppeng Regency. This study used 2 cycles, namely cycle I and cycle II which consisted of planning, implementing, observing, and reflecting. Data collection techniques used test and non-test techniques. Data analysis techniques using quantitative and qualitative analysis techniques. Based on the results of data analysis, this research was considered sufficient and successful, because the students' learning outcomes had reached 75% of the KKM and mastery in class had reached ≥75%. In conclusion, the multi-strategy method can improve the quality of learning. This increase was caused by an increase in student learning activity which was created by good interaction and collaboration between teachers and students, as well as students and students in a democratic manner so that the learning process was very dynamic.   Keywords: Student Activity, Learning Outcomes, Multistrategic Metho

Apsidal motion and light a curve solution for eighteen SMC eccentric eclipsing binaries

Aims: The Danish 1.54-meter telescope at the La Silla observatory was used for photometric monitoring of selected eccentric eclipsing binaries located in the Small Magellanic Cloud. The new times of minima were derived for these systems, which are needed for accurate determination of the apsidal motion. Moreover, many new times of minima were derived from the photometric databases OGLE and MACHO. Eighteen early-type eccentric-orbit eclipsing binaries were studied. Methods: Their (O-C) diagrams of minima timings were analysed and the parameters of the apsidal motion were obtained. The light curves of these eighteen binaries were analysed using the program PHOEBE, giving the light curve parameters. For several systems the additional third light also was detected. Results: We derived for the first time and significantly improved the relatively short periods of apsidal motion from 19 to 142 years for these systems. The relativistic effects are weak, up to 10% of the total apsidal motion rate. For one system (OGLE-SMC-ECL-0888), the third-body hypothesis was also presented, which agrees with high value of the third light for this system detected during the light curve solution.Comment: 8 pages, 5 figures, 4 tables, plus the appendix data tables with times of minima. Published in 2014A&A...572A..71

Do the Herschel cold clouds in the Galactic halo embody its dark matter?

Recent Herschel/SPIRE maps of the Small and Large Magellanic Clouds (SMC, LMC) exhibit in each thousands of clouds. Observed at 250 microns, they must be cold, T ~ 15 K, hence the name "Herschel cold clouds" (HCCs). From the observed rotational velocity profile and the assumption of spherical symmetry, the Galactic mass density is modeled in a form close to that of an isothermal sphere. If the HCCs constitute a certain fraction of it, their angular size distribution has a specified shape. A fit to the data deduced from the SMC/LMC maps supports this and yields for their radius 2.5 pc, with a small change when allowing for a spread in HCC radii. There are so many HCCs that they will make up all the missing Halo mass density if there is spherical symmetry and their average mass is of order 15,000 Mo. This compares well with the Jeans mass of circa 40,000 Mo and puts forward that the HCCs are in fact Jeans clusters, constituting all the Galactic dark matter and much of its missing baryons, a conclusion deduced before from a different field of the sky (Nieuwenhuizen, Schild and Gibson 2011). A preliminary analysis of the intensities yields that the Jeans clusters themselves may consist of some billion MACHOs of a few dozen Earth masses. With a size of dozens of solar radii, they would mostly obscure stars in the LMC, SMC and towards the Galactic center, and may thus have been overlooked in microlensing.Comment: Revised and corrected version, matches published version. Conclusions unchange

A Phase Lag between Disk and Corona in GRMHD Simulations of Precessing Tilted Accretion Disks

In the course of its evolution, a black hole (BH) accretes gas from a wide range of directions. Given a random accretion event, the typical angular momentum of an accretion disc would be tilted by $\sim$60$^\circ$ relative to the BH spin. Misalignment causes the disc to precess at a rate that increases with BH spin and tilt angle. We present the first general-relativistic magnetohydrodynamic (GRMHD) simulations spanning a full precession period of highly tilted (60$^\circ$), moderately thin ($h/r=0.1$) accretion discs around a rapidly spinning ($a\simeq0.9$) BH. While the disc and jets precess in phase, we find that the corona, sandwiched between the two, lags behind by $\gtrsim 10^{\circ}$. For spectral models of BH accretion, the implication is that hard non-thermal (corona) emission lags behind the softer (disc) emission, thus potentially explaining some properties of the hard energy lags seen in Type-C low frequency quasi-periodic oscillations in X-Ray binaries. While strong jets are unaffected by this disc-corona lag, weak jets stall when encountering the lagging corona at distances $r \sim 100$ black hole radii. This interaction may quench large-scale jet formation.Comment: 5 pages, 4 figures, submitted to MNRAS, see YouTube playlist for 3D renderings: https://www.youtube.com/playlist?list=PLDO1oeU33GwmwOV_Hp9s7572JdU8JPSS

Simulation of the hydrogen ground state in Stochastic Electrodynamics

Stochastic electrodynamics is a classical theory which assumes that the physical vacuum consists of classical stochastic fields with average energy $\frac{1}{2}\hbar \omega$ in each mode, i.e., the zero-point Planck spectrum. While this classical theory explains many quantum phenomena related to harmonic oscillator problems, hard results on nonlinear systems are still lacking. In this work the hydrogen ground state is studied by numerically solving the Abraham -- Lorentz equation in the dipole approximation. First the stochastic Gaussian field is represented by a sum over Gaussian frequency components, next the dynamics is solved numerically using OpenCL. The approach improves on work by Cole and Zou 2003 by treating the full $3d$ problem and reaching longer simulation times. The results are compared with a conjecture for the ground state phase space density. Though short time results suggest a trend towards confirmation, in all attempted modelings the atom ionises at longer times.Comment: 20 pages, 9 figures. Published version, minor change

Photopolymerizable monomer formulations for nanoporous proton conducting membranes

Several monomers and crosslinker in a broad range of concentrations in water and 1-Methyl-2-pyrrolidone (NMP) respectively were screened for their mechanical properties, water uptake and conductivity by photo polymerization with a polar photo initiator in porous membranes made of polypropylene and polyethersulfone respectively. As conductive polymer, primarily poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) and poly(2-sulfoethyl methacrylate) (PSEM) respectively as well as polymers of phosphonic acid containing monomers or newly synthesized monomers were used. The conductive monomers were crosslinked with varying hydrophobic and hydrophilic multifunctional monomers like N,N'-methylene bisacrylamide (MBA), 2-Propenoic acid, 2-methyl-, 1,1'-(1,10-decanediyl) ester (D3MA) or polyethyleneglycol diacrylates with two varying chainlengths (PEG-DA700, PEG-DA330). Furthermore several new multifunctional crosslinker with enhanced thermal and ageing stability have been synthesized and tested.\ud The advantage of several different building blocks with known characteristics is the possibility to tune the polymer to special needs of an application. For example, some polymer compositions have good conductivity at lower temperatures whereas other polymers develop better properties at elevated temperatures