Jurnal Pendidikan Kimia
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Carbon Ink Characterization from Banana and Cassava Peels by Carbonization Method
Get PDFBanana and cassava plants are the most growing plants in the world. The use of both plant's peel is usually for animal feed. This research is intended to utilize banana and cassava peel as a raw material of whiteboard ink markers by varying concentration of the carbons to see its effect on the characteristics of the ink. The carbon concentration variations are 25 g, 30 g, 35 g, 40 g, and 45 g, which is dissolved in 100 ml of the solution. The steps of this research include the carbonization of banana or cassava peel, and then its carbon powder is sifted by 200 mesh. The powder will be dissolved in 50 ml of Arabic gum 10%, 15 ml of PEG-7, and 35 ml of alcohol 70%, then the solution stirred until homogeneous. The result showed that the addition of the Banana or cassava peels carbon concentration effect on the value of density, viscosity, pH, and pigment ink. The characteristic whiteboard ink markers from the banana peel that accordance with the commercial ink. It is consists of 30% Banana peel carbon concentration with a density value of 1.0077 g/cm3, viscosity value of 6.2049 cP, pH value of 10.55, and the ink pigment are close enough with the commercial refill ink. While the characteristic from cassava consists of 35% cassava peel carbon concentration with a density value of 1.0893 g/cm3, viscosity value of 15,2427 cP, pH value of 8,75, and the ink pigment are close enough with the commercial in
Determination of Chlorine on Brewed Robusta Coffee (Coffea canephora var. Robusta) with V60 Method
Get PDFOne of the manual brewing techniques is the pour-over V60 method. It uses a filter paper, which is suspected of containing chlorine as a paper bleaching agent that will dissolve in coffee. Health problems that can be caused by consuming chlorine-containing beverages in the long term can cause directly disease related to liver, bladder, intestinal cancers, arteriosclerosis, high blood pressure, pneumonia, bronchitis, dyspnea, and allergies. This study aims to determine the chlorine content of brewed robusta coffee using the brew V60 method. The chlorine test with the colour reaction method and the precipitation test as qualitative analysis to determine chlorine levels is an argentometric titration with the Mohr method. This research shows that all three samples of filter paper and coffee with V60 brewing method contain chlorine. The titration result shows that chlorine levels in filter paper brand A are 81.9 mg/L, brand B 49.9 mg/L, and brand C 69.9 mg/L. Levels of chlorine in V60 brewed coffee brand A are 44.6 mg/L, brand B 21.9 mg/L, and brand C 28.6 mg/L. This research concludes that the chlorine content in filter paper and V60 coffee brewing beverages on brand A, brand B, and brand C is unqualified according to WHO regulation about chlorine qualification for clean drinking water, which is 5 mg/L
Students' Cognitive Analysis using Rasch Modeling as an Assessment for Planning of Strategies in Chemistry Learning
Get PDFRasch modelling based on assessment can help teachers analyze the students' cognitive knowledge level and development. However, teachers are considered unsuccessful in teaching where the achievement of indicators in learning science, such as chemistry, is not holistically actualized. This study aimed to analyze High School students' knowledge in Banjarmasin City, especially on students' knowledge (cognitive aspect), using the Rasch modelling data analysis technique and exploring how chemical learning strategies are planned based on the symptoms of the data obtained. The data collection technique used a dichotomous format test technique (multiple choices). The research method used was descriptive with a quantitative approach to examine Rasch's various data, which was then interpreted qualitatively to describe the issues raised. The study results show that person reliability (students) based on Rasch modelling analysis is +0.79, and item reliability is +0.98, where the value indicates that the consistency of the participant response pattern is "sufficient." Then, the mean person measure is -0.07, while the mean item is 0.00. It means that the participants' "mean value" is below the "mean value" of the item that the students' ability is below the item's ability. The Rasch data's recapitulation value showed that the response patterns of various data symptoms and those data were interpreted. It showed students' knowledge of atomic structure material was still considered low based on the Rasch model criteria. This is a reference for making appropriate chemical learning strategy plans to improve their knowledge. In conclusion, Rasch modelling-based assessment is effectively used in analyzing students' (cognitive) ability on atomic structure material. These results produce a strategic plan like what in chemistry learning such as the importance of conducting further diagnoses using misconception tests, identifying students' learning styles, constructing students' knowledge through the concept of chemical representation, and developing appropriate learning media according to their needs (students)
Determination Stability of 99mTc-Etambutol Radiopharmaceuticals for Tuberculosis Detected
Get PDF99mTc-ethambutol radiopharmaceutical is a diagnostic kit based on the anti-tuberculosis drug, ethambutol, labeled with radioactive tracer 99mTc. This radiopharmaceutical is a result of research development in Centre for Radioisotope and Radiopharmaceutical Technology, BATAN. 99mTc-ethambutol radiopharmaceutical in the hospital used as a diagnostic agent for tuberculosis detected, particularly tuberculosis in extra pulmonary organs that is not easily detected by existing conventional methods. The aim of study to find out how stable ethambutol kit when stored at certain temperature and how stable ethambutol stability after labelled with 99mTc. These stability data are required by hospitals which used 99mTc-ethambutol . The stability test performed by measuring the radiochemical purity of ethambutol kits which were stored at certain time period and labelled with 99mTc using thin layer chromatography (TLC) method. Radiochemical purity tests were also performed on 99mTc-ethambutol at certain time period after its labeling process. Based on experiment results, it was obtained that ethambutol kit was still stable for up to 9 months when stored at refrigerator temperature 8 oC with percentage of radiochemical purity average > 85% and up to 11 months when stored in deep freezer temperature -80 oC with percentage of radiochemical purity average 90%. While 99mTc-ethambutol was still stable for up to 4 hours after labeling with percentage of radiochemical purity more than > 85%
Comparison Study Between Local TSH IRMA Kit (CRRT) and Imported TSH IRMA Kit (Riakey, Korea)
Get PDFThyroid Stimulating Hormone (TSH) is one of hormones that our body need for growth of brains, bones and other tissues and regulate the metabolism in the body. Normal range of TSH for adult is from 0.3 to 5.5 µIU/ml, whereas for baby ranged from 3 to 18 µIU/ml. An Immunoradiometricassay (IRMA) is one of immunoassay technique using radionuclide as the tracer to detect low quantity of analyte. This technique is suitable for determine TSH levels in human blood serum which has complex matrix and various concentration. The Center for Radioisotope and Radiopharmaceutical Technology (CRRT)-BATAN has developed a reagent of TSH IRMA kit. The aim of this research is to compare between local TSH IRMA kit (CRRT-BATAN) and imported TSH IRMA kit (Riakey, Korea) toward 110 adult samples obtained from PTKMR - BATAN. The results showed 97 samples as true negative, 5 samples as true positive, 1 sample as false negative and 7 samples false positive. The comparison study gave diagnostic sensitivity as much as 83.33 %, diagnostic spesificity as much as 93.27 % and accuracy as much as 92.72 %
Socratic Questioning Method in The Colloid System Topics Using The Participatory Action Research (PAR)
Get PDFThe purpose of this research is to identify how lesson plans prepared based on socratic questions can improve critical thinking skills. Research method used is Participatory Action Research (PAR), data collection techniques through interviews and questionnaires. It is expected that the results of the research can be applied in schools specifically to produce lesson plans in colloidal learning integrated with TPACK (Technological Pedagogical Content Knowledge). The results showed the teacher gave a positive assessment of 85% on the socratic questions contained in the lesson plan. This will provide stimulants to students in order to able to argue and practice their critical thinking skills. Postgraduate student participants also gave a positive response of 87.5%. It can be concluded that both teacher participants and postgraduate students agree with the application of socrates questions to students because they have a positive impact on critical thinking skills. Thus, this initial stage of research can proceed to the next stage of PAR research
Quality and Detergency Optimization, Liquid Detergent Preparation, Mahogany Seed Extract (Swietenia mahagoni)
Get PDFThe use of Linear Alkylbenzene Sulfonate(LAS) as a surfactant for making detergent can pollute aquatic ecosystem and agricultural soils. Mahogany seed extract can be used as a substitute for LAS because it contains saponin so that it can be used also as a foaming agent to remove dirt on clothes. This research aims to know the optimum liquid detergent formula seen from its suitability with SNI 06-4075-1996 about Liquid Washing Detergents, foam stability and detergency power. The research steps are (1) Making simplicia (2) Extracting mahogany seeds with ethanol solvent (3) Identification of saponin (4) Making liquid detergent preparations (5) Quality test, foam stability test and detergency power. The results showed that formula 2 with a ratio of mahogany seed extract : LAS is 2 : 1 is the most optimum formula because it appropiate with SNI, and has the best foam stability and detergency power. Formula 2 has pH 11.1; specific gravity 1.1; 0.1% free alkaline, foam stability of 70% and detergency without rinsing 91.53% and by rinsing 94.680%.
Development of Computerized Testlet to Measure Science Process Skill on Stoichiometry
Get PDFThis research aims to develop a computerized testlet assessment to measure science process skills on stoichiometry material in terms of validity, reliability, difficulty level, distinguishing features and deception indexes that meet the criteria as good assessment instruments, and can display individual profiles of science process skills students. The subject of the research trial was a grade X student of Senior High School in Boyolali. Validity test is done by content validity, criteria, and expert validation. Reliability test is done by finding the price of the reliability coefficient r. Characteristics test is done by determining the level of difficulty, distinguishing features and deception index. The profile of science process skills is determined by measuring students' mastery of the science process. The results of the research and development was declared feasible and met the criteria as a good question with a validity of questions more than 0.79 (valid), has a test reliability on the main field trials of 0.643 and 0.610 on the trial the implementation of the field is relatively high, has a distinguishing power with a percentage of 10% bad, 66.7% is sufficient, and 23.3% is good, has a difficulty level with a percentage of 20% difficult, 53.3% moderate and 26.7% easy
Identification of Students Misconception Using Two-Tier Diagnostic Test Completed with Certainty of Response Index (CRI) on Topic Partial Salt Hydrolysis
Get PDFThis study’s aim was to find misconception pattern on partial salt hydrolysis on eleventh grade student science major at SMA Negeri 2 Sukoharjo. Misconception was identified using two-tier diagnostic test completed with CRI supported by observation on learning process also interview. Two-tier diagnostic test composed of 16 questions. The approach of this study was qualitative description which was held in February-June 2018. The subject of this study were the eleventh grade students class IPA 1 and IPA 4 as many as 72 students. According to the result showed that there was misconception on almost every concept’s part. Based on the student answer analysis result shows if the pH, relative atomic mass, and volume were known student were having biggest misconception on counting salt’s mass are, 75%. The reason of misconception that occurs on partial salt hydrolysis is come from the student it self that is student’s uncomplete reasoning pattern