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Elvinawati Elvinawati, Elvinawati
University of Bengkulu

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AKTIVITAS ANTIOKSIDAN DAN ANTIBAKTERI EKSTRAK DAUN Jatropha gossypifolia L Pangestu, Nia Sapitri; Nurhamidah, Nurhamidah; Elvinawati, Elvinawati
Alotrop Vol 1, No 1 (2017)
Publisher : FKIP University of Bengkulu

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This study was conducted to determine the activity of Jatropha gossypifolia L (jarak merah’s) leaf extract as an antioxidant and antibactery against acne causing bacteria (Propionibacterium acnes). To obtain an J. gossypifolia L jarak merah’s leaf extract by maceration using 96% ethanol, and then fractionated with n-hexane and ethyl acetate. Testing of antioxidant activity by DPPH method and antibactery activity test by the paper disc method. Antioxidant activity test has done for ethanol fraction, ethyl acetate fraction and n-hexane fraction, while testing for antibacterial activity performed on fractions active as antioxidant. The test results demonstrate the antioxidant activity of ethyl acetate fraction and the ethanol fraction as a fraction very strong with IC50 value of 22.33 ppm for ethyl acetate fraction and 41.04 ppm for ethanol fraction. Then the fraction of ethyl acetate and ethanol fraction antibactery activity test, the result is known that both factions have the ability to inhibit the growth of bacteria Propionibacterium acnes demonstrated by the inhibition zone is formed. In 1000 ppm is formed diameter of the greatest inhibition zone that is equal to 6 mm for ethyl acetate fraction and 5 mm for ethanol fraction.
PERBANDINGAN HASIL BELAJAR SISWA MENGGUNAKAN MEDIA CHEMOPOLY GAME DAN TOURNAMENT QUESTION CARDS Viani, Dui Sherly; Bahar, Amrul; Elvinawati, Elvinawati
Alotrop Vol 1, No 1 (2017)
Publisher : FKIP University of Bengkulu

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The low learning outcomes of the students is because in the learning process of teacher and student interaction only goes one way. Teachers often use lecture methods so that students tend to only accept what is given. This can make the students motivation and activeness in following the lesson to be low. Therefore, researchers try to vary the cooperative learning model using Chemopoly Game media and Tournament Question Cards. This is quasi experimental research with population class X MIPA in SMAN 2 Kota Bengkulu and sample is class X MIPA C using media Tournament Question Cards and class X MIPA D using Chemopoly Game media. Data analysis used were mean score, normality test, homogeneity test, and t test. The average posttest grade of experiment I is 85,59 While for experiment class II is 79,38. Then t test and obtained tcount> ttable (2.62> 2.38). The results of this study indicate that there is a significant difference between student learning outcomes using Chemopoly Game media and Tournament Question Cards on basic chemical law materials.
PENERAPAN MODEL DISCOVERY LEARNING DENGAN MENGGUNAKAN MEDIA VIDEO UNTUK MENINGKATKAN AKTIVITAS BELAJAR DAN HASIL BELAJAR SISWA KELAS XI IPA 1 SMAN 1 KOTA BENGKULU Medianty, Sitti Utami; Bahar, Amrul; Elvinawati, Elvinawati
Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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[APPLICATION OF DISCOVERY LEARNING MODEL BY USING VIDEO MEDIA TO INCREASE LEARNING ACTIVITIES AND STUDENT LEARNING RESULT CLASS XI IPA 1 SMAN 1 BENGKULU CITY]. The research has goals to improve the activity and learning outcomes chemistry at XI IPA 1 class in SMA Negeri 1 Bengkulu that consist of 30 students: 23 girls and 7 boys. This study is research of class action on thermochemistry subjects by discovery learning model. This research consist three cycle on four stage: planning, action, absorption, and reflection. The data collected using test and non test that consist of post test and observation sheet of activity teacher and student. The data processed using quantitative simple analysis techniques: average score of observation sheet of activity teacher and student, average score, absorption percentage clasical, andclasssical learning completness percentage. From the reseult, we can conculded that chemistry learning process applying discovery learning model using video can improve activity and outcomes learning chemistry student. It can be see from the average score of students. In the first cycle is 69.33 in which the percentage of classical absorption is 86.67 and classical learning completeness is 66.67. The average score of the second cycle is 71,33 in which the percentage of classical absorption is 89.17 and classical learning completeness is 73.33. The students’ average score of the third cycle is 81.33 in which the percentage of classical absorption is 90.37 and classical learning completeness is 86.67. The teacher’s activities of the learning process in the first cycle get average score 26.5 and it is good category, the second cycle is 27.5 and it is good category, the third cycle is 30 and it is good category too. Meanwhile, the student’s activities in the first cycle get average score 22.5 and it is good category, the second cycle is 25 and it is a good category, the third cycle is 27 and it is good category.
PEMANFAATAN EKSTRAK AIR BUAH Flacourtia inermis Roxb. (LOBI-LOBI) SEBAGAI PENGAWET IKAN LAUT Pribadi, Ade; Nurhamidah, Nurhamidah; Elvinawati, Elvinawati
Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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[THE  UTILIZATION OF   Flacourtia inermis Roxb. (LOB-LOBI ) FRUIT WATER EXTRACTS AS A MARINE FISH PRESERVATIVE] This research aims to determine the magnitude of the concentration and the length of time the optimum soaking water extracts of fruit Flacourtia inermis Roxb. (lobi-lobi ) as well as measuring its potential for use as a preservative in marine fish. Sample marine fish used is Kerapu Macan (Epinephelus fuscogultatus). The concentration of water extract from the fruit of F.inermis Roxb  is at levels at 10, 20, 30 and 40% with soaking time each at 1, 2 and 3 hours for any variation of the concentration. Observation of the level of the fish freshness is done with a variety of storage time of 12, 18, and 24 hours at room temperature to any variation of the concentration of extract and soaking time. The parameters used in determining the level of the freshness of the sample fish is a rate of Total Volatile Bases (TVB), moisture content, and pH. The results of the research done indicate that extracts water from the fruit of F.inermis Roxb L are potential for use as a preservative of marine fish based on the values of pH and the levels of TVB. The most optimum concentration and soaking time in Kerapu Macan fish preserve during its storage was soaking with a concentration of 30% for 1 hour, i.e., able to withstand the pace of the decline of the quality of the Kerapu Macan sample for 18 hours at room temperature: with the pH 6.7 and fish TVBvalue at 29.4 mgN/100 g.
KARAKTERISASI ISOTERM ADSORPSI DARI ION LOGAM BESI (Fe) PADA TANAH DI KOTA BENGKULU Apriyanti, Hesti; Candra, I Nyoman; Elvinawati, Elvinawati
Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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[CHARACTERIZATION OF THE  ADSORPTION FROM IRON METAL IONS ISOTHERM ON THE SOIL IN BENGKULU CITY] Level of micronutrient elements Fe takes part in determining the fertility rate of agricultural land. Continuous oxidation of Fe the soil will cause soil poisoning, due to the soil saturated in absorb of Fe. This research aims to determine the characteristics of the soil, adsorption and its ability in absorption isotherm on  Fe metal. Soil samples were taken from the farm in the city of Bengkulu. The characteristics of the soil tested, i.e., water content, pH, and soil type. Adsorption isotherm type is a determination as Langmuir or  Freundlich isotherm. Soil sample after it is dried and cleaned and then milled and sieved at 100 mesh sieve. Moisture content is measured by dried in an oven for 24 hours and the measurement of the difference between the initial and the final weight of the soil. Determination of soil pH is measured by the pH meter on the CaCl2, and soil type is determined by calculating the percentage of sand, silt, and clay from the soil. Maximum adsorption capacity is determined from Fe adsorption isotherm after getting the pH, the weight of adsorbent and optimum contact time. Adsorption Isotherm was determined by adsorption of aqueous Fe variation at the concentration of  2.5; 5; 10; 15; 20; and 25 ppm on optimum pH and weight, and stirred at an optimum contact time, then filtered and measured its absorbance with UV-Vis spectrophotometer. Results of research results in the form of moisture content average 23.5%, soil pH value at 5 and soil type, i.e., dusty clay with the dominant form of Isotherm adsorption is a Freundlich isotherm, and the capacity of soil in adsorbing of iron on this research obtained is amounting to 45.6.
PENERAPAN MODEL PEMBELAJARAN INKUIRI DENGAN MEDIA DART BOARD UNTUK MENINGKATKAN HASIL BELAJAR KIMIA Di KELAS XI IPA 1 SMA NEGERI 9 KOTA BENGKULU TAHUN AJARAN 2016/2017 Wulandari, Defrilina Sri Eka; Bahar, Amrul; Elvinawati, Elvinawati
Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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[THE  APPLICATION OF INQUIRY LEARNING MODEL WITH  DART BOARDMEDIA TO IMPROVE THE STUDIED RESULTS OF  CHEMISTRY IN CLASS XI IPA 1 SMA NEGERI 9 CITY OF BENGKULU  AT 2016/2017 ACADEMIC YEAR]  This research aims to improve the learning outcomes and student activity model of learning by implementing a inkuiri dart board with media in class XI IPA 1 SMA Negeri 9 Bengkulu city at 2016/2017. Academic year. This research is a class action research. This research was conducted in three cycles consisting of 4 stages each namely planning, implementation, observation, and reflection. The subject of this research is the whole grade X IPA 1 SMA N 9 Bengkulu city on 2016/2017 academic year. From the results, it can be concluded that the process of learning to apply inquiry learning models by using a Dart Board media proved can improve the activity and outcomes of study chemistry grade XI IPA 1 SMA Negeri 9  Bengkulu city on 2016/2017 academic year. It can be seen from the average value of students in Ist cycle are 61.61, classical absorption 77.02% and learning of classical completeness at 19.35%..In Iind Cycle obtained an average score of students amounted to 71.29; absorption of conventional 79.21% and  completeness studied conventional 35.48%. In IIIth cycle received an average rating of students at 84.51; absorption of conventional 84.51% and  completeness  studied classical 90.32%.. For the entire sequence of an increase in the activity of the students which can be seen from the mean value – 1st cycle averages of 22.5, 2nd cycle at 25; and in 3th cycle at 29.
PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE COURSE REVIEW HORAY(CRH) UNTUK MENINGKATKAN MOTIVASI DAN HASIL BELAJAR KIMIA SISWA SMA N 1 KOTA BENGKULU Zulhulaifah, 1Nurul; Nurhamidah, Nurhamidah; Elvinawati, Elvinawati
Alotrop Vol 2, No 2 (2018)
Publisher : FKIP University of Bengkulu

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This study is a classroom action research applying the Course Review Horay learning model on the subject of basic chemical laws and chemical reaction equations in three cycles with four stages: planning, implementation, observation and reflection on each cycle aimed at improving motivation, activity and results learning chemistry of students of class X IPA 5 SMA N 1 Kota Bengkulu academic year 2017/2018. The study was conducted in March-April of 2018 with a total of 27 students, consisting of 17 women and 10 men. The data were obtained using questionnaire of motivation, posttest and observation sheet of teacher and student activity, which was processed using simple quantitative analysis technique, mean score of motivation questionnaire and observation sheet, percentage of classical absorption and classical learning completeness. From the results of this study it can be concluded that the application of CRH learning model proved able to increase the students' motivation, activity and chemistry learning achievement to reach the minimum mastery criteria of ?75 in the third cycle. Student learning motivation increased every cycle from pre cycle up to cycle III 35,69% (low), 38,95% (low), 59,71% (medium) and 78,96% (high) respectively. The activities of teachers and students also increased each cycle in a row: teacher activity scores: 36, 38 and 38.5 with good category and student activity score: 29 (enough), 37,5 and 38 with good category. Student learning outcomes in cycle I obtained an average value of 54.3; 54.3% classical absorption and 16% classical learning completeness. In cycle II, the average score is 72.5; 72.5% classical absorption and 57.69% classical learning completeness. In cycle III, the average score is 78.76; 78.76% classical absorption and 84.61% classical learning completeness
ANALISIS ION MERKURI (II) MENGGUNAKAN NANO PARTIKEL PERAK TERIMOBILISASI PADA KERTAS SARING Meileza, Nessi; Firdaus, M. Lutfi; Elvinawati, Elvinawati
Alotrop Vol 2, No 2 (2018)
Publisher : FKIP University of Bengkulu

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The aims of this research is improve stability and sensitivity of silver nanoparticles (NPP) immobilizatied on filter paper. Silver nanoparticles synthesized by reducing the ascorbic acid using a chemical reduction method. Immobilization NPP on filter paper is done with the technique of immobilization (immunosystem) is the process of molecular bonding reagent in supporting materials, so physically bound NPP the surface of filter paper is composed of cellulose fibers. The results obtained for the stability of immobilization NPP on filter paper can be last up to stable 60-daywhile liquid NPP stability can only last for 30 days. To maintained the stability ofimmobilization on filter paper is saved in a closed box. For the determination of sensitivity of immobilization NPP in the filter paper test is performed against the mercury (II) ion with each different concentrations. The results obtained for sensitivity of immobilization NPP on the filter paper is analyzed in digital image can be detect mercury (II) ion until the concentration of ppb. The results of measurement Limit of Detection (LOD) or limit the smallest NPP can detect mercury (II) ion is under 0.863 ppb, while liquid NPP able to detect only concentration 1.448 ppb.. The results of this research NPP immobilization on filter paper can be an alternative to increasingstability and sensitivity of NPP compared with liquid  NPP, and can be applied into the colourimetry indicator is inexpensive and practical to analysis of mercury (II) ion in the digital image.