Efektivitas Penggunaan Media Pembelajaran Video Untuk Meningkatkan Pengetahuan Kesiapsiagaan Siswa Terhadap Bencana Gempabumi Dalam Kegiatan Ekstrakurikuler Ssb Di Smp Negeri 2 Kemalang Kabupaten Klaten

This study is an experiment aimed at explaining and predicting that will happen on a variable when given a particular treatment on other variables. The design used yauitu randomized control group pre test-pascatest design in which treatment is given before, both experimental group or a control group given prates first as preliminary tests. Data analysis techniques using the test validity, the test of normality, test its homogeneity, and test the hypothesis that they are using the help of SPSS software 24. The data obtained showed that the control class scored an average of 64, while experimental classes scored an average of 84. Pre test in the study got the value of the sig (2-tailed) value is greater than the probability of 0.149 > H0 is accepted then the class post test gets the value of the Sig (2-tailed value lower than 0.05 0.00 then H0 is rejected. Conclusions there is an increase in the results of a study using video media materials gempabumi in junior high Country 2 Kemalang, Sukoharj

Preparation, characterization and application of CuCrO2/ZnO photocatalysts for the reduction of Cr(VI)

International audienceThe delafossite CuCrO2 elaborated by sol-gel from 40 nm diameter colloid is optically active in the visible region. It is characterized physically and photoelectrochemically. The microstructure is fairly homogenous with a mean crystallite size of ca. 2 μm. The optical gap (1.30 eV), determined from the diffuse reflectance, is well suited to the sunlight spectrum. The Mott Schottky plot is characteristic of P-type conductivity with a flat band potential of -0.26 VSCE. As application, the photoreduction of chromate is successfully achieved in air-equilibrated suspension CuCrO2/ZnO (1/1). CuCrO2 is photoactivated by visible light and the electrons in the conduction band (-1.34 VSCE) are injected to ZnO. In the presence of salicylic acid, a conversion of Cr(VI) to Cr(III) of 57% is obtained under optimal conditions (pH 3 at 25°C, 5×10−4 mol/L) because of the HCrO4 − dark adsorption onto ZnO (4HCrO4 − + 3C7H6O3 + 18O2 + 16H+ −→ 4Cr3+ + 21CO2 + 19H2O, ΔG0 = -557 kcal/mol). Prolonged illumination is accompanied by a deceleration in the photoactivity owing to the competitive water reduction, an issue of energetic concern. The hetero-system exhibits self sensitization for hydrogen production with an evolution rate of 149 μmol/(hr*g)