97 research outputs found
Analysis of differentiated learning implementation in elementary schools during the 2020-2024 period
No full textDifferentiated learning is a learning strategy that emphasizes the importance of the process of adjusting learning strategies that can meet the needs of each student with various ability backgrounds, especially in Elementary Schools. Differentiated learning recognizes that each student has a different learning style, learning speed, and interests. At the elementary school level, where students are actively developing their various abilities and potentials, this approach is very important to implement so that it can ensure that each student can learn optimally and achieve their best potential. This study aims to review various existing literature on the effect of implementing differentiated learning in elementary schools for the 2020-2024 period by analyzing 10 articles that have been published in relevant journals using Harzing's Publish or Perish and Google Scholar applications. Each article was analyzed and the results of the analysis were arranged in a table that included the title, author's name, year of publication, and research findings. The results of the analysis showed that differentiated learning was able to increase participation motivation and student learning outcomes with quite significant results compared to learning with conventional methods. This can be seen from several studies that show an increase in cognitive abilities and student learning outcomes. This study recommends ongoing training for teachers related to the implementation of differentiated learning with effective and efficient time management, as well as collaboration between all parties such as parents and learning communities, as well as the use of technology as an integral part of efforts to create a more inclusive and student-centered learning environment, especially in elementary schools
EFFECT OF TIME AND TEMPERATURE ON ISOMERIZATION REACTION OF ?-PINENEUSING CATALYST ZR 4+ Nanik Wijayati, Supartono, Nuni Widiarti, Tri Handayani /NATURAL ZEOLITE
No full textEffects of time and temperature on ?-pinene isomerization reaction using catalysts Zr/natural zeolitewas studied. Characterization of the catalysts include: crystallinity, observed using X-Ray Diffraction, count Zr 4+ carried observed using X-Ray Fluorescence, area and porosity catalyst was observed using the Surface Area Analyzer, and acidity catalyst observed through gravimetric method. Isomerization reaction carried out in a batch reactor with temperature variations 90, 120 and 150 C and reaction time variations of 60, 90, 120, 150 and 180 minutes. Best results of isomerisation in this study was obtained at 150 derajat C with a reaction time of 180 minutes. Kindsof isomer obtained was observed using GCMS. Catalyst characterization results indicate that modification of the catalyst by cation Zr increases the acidity from 2.76 to 6.64 mmol/g and does not damage the crystal structure significantly. The highest product conversion in this research is 9.24%, less than the maximum results caused by pre-treatment of the catalyst produces a low area. Thus, temperature and reaction time affect the concentration of ? pinene isomerization product in addition to the effect of the catalyst used
Modifikasi Batu Kapur Madura Dan Aktivitas Katalitiknya Pada Reaksi Transesterifikasi Minyak Nabati Menjadi Biodiesel
No full textBatu kapur (CaMg(CO3)2) Madura, Indonesia telah dimodifikasi dengan berbagai surfaktan antara lain cetyltrimethylammonium bromide (CTAB), Polyethylene glycol (PEG), dan rarasaponin untuk memperoleh CaO/MgO. Tujuan dari penelitian ini adalah menghasilkan material katalis CaO/MgO dengan luas permukaan yang tinggi dan ukuran partikel yang lebih kecil melalui metode kalsinasi-hidrasi-dehidrasi (CHD). Dekomposisi termal dolomit CaMg(CO3)2 dilakukan pada 900 °C selama 3 jam. Proses CHD dengan berbagai surfaktan (CTAB, PEG, dan rarasaponin) dilakukan dengan metode sonikasi dan hidrotermal. Modifikasi NiO dengan CaO/MgO-P untuk meningkatkan stabilitas katalis dilakukan dengan impregnasi. Hasil penelitian menunjukkan bahwa PEG bertindak sebagai surfaktan terbaik menghasilkan katalis CaO/MgO-P dengan ukuran partikel ̴ 377 nm, luas area 39 m2/g, volume pori (0,0322 m3/g) dan kebasaan (7,8 mmol/g). Kondisi optimal reaksi transesterifikasi minyak kelapa dengan CaO/MgO-P dicapai pada: rasio metanol: minyak (1: 9), beban katalis (5%), dan suhu reaksi (125 °C) menghasilkan biodiesel sebesar 81,76%. Keberadaan NiO pada katalis 5% NiO/CaO/MgO-P memberikan sisi asam dan basa katalis yang dapat meningkatkan hasil biodiesel hingga 90%. Kinetika reaksi transesterifikasi dengan katalis NiO/CaO/MgO merupakan reaksi pseudo orde satu dengan nilai A= 35,07 min-1 dan nilai Ea = 24,47 kJ/mol. Parameter termodinamika seperti ΔH, ΔS dan ΔG diperkirakan masing-masing 21,31 kJ/mol, -0,226 kJ/mol dan 111,259 kJ/mol. Sifat biodiesel yang meliputi kinematik, densitas, titik nyala, bilangan asam, dan residu karbon diperoleh berturut-turut 1,93 mm2 /s, 0,86 g/cm3, 137 °C, 0,27 mg KOH /g, dan 0,22%. Uji reusabilitas katalis NiO/CaO/MgO menunjukkan bahwa katalis stabil selama 2 siklus dengan yield biodiesel sebesar 89,00 % pada siklus pertama dan menurun drastis menjadi 51,95 % pada siklus ke empat.
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Limestone (CaMg(CO3)2) from Madura, Indonesia has been modified with various
surfactan including cetyltrimethylammonium bromide (CTAB), Polyethylene
glycol (PEG), and rarasaponin to obtain a CaO/MgO. The aim of the research is to
produce a high surface area and smaller size particle of transesterification catalyst
material via the calcination-hydration-dehydration (CHD) method. The thermal
decomposition of dolomite CaMg(CO3)2 was conducted at 900 °C. The CHD
treatment with various surfactant (CTAB, PEG, and rarasaponin) were proceed by
sonication and hydrothermal method. The catalytic performance was carried out on
coconut oil transesterification reaction. The modification NiO with the CaO/MgO
to improve activity dan stability of the catalyst were proceed by impregnation. The
results shows that PEG act as a better surfactant to produce CaO/MgO-P catalyst it
indicated by the particle size of catalyst was about 377 nm, surface area (39 m2
/g),
pore volume (0.0322 m3
/g) and the basicity (7.8 mmol/g). The optimal conditions
transesterification reaction of coconut oil with CaO/MgO-P were achieved at:
methanol:oil ratio (1:9), CaO/MgO-P catalyst load (5%), and the reaction
temperature (125 °C) to yield biodiesel of 81.76%. The presence of NiO provide an
acidic- and basic- sites on NiO/CaO/MgO catalyst which can improve up to 90%
biodiesel yield. The kinetics of the transesterification reaction with a
NiO/CaO/MgO catalyst controlled by a pseudo first order with a value of A= 35.07
min-1
and a value of Ea = 24.47 kJ/mol. The thermodynamic parameters such as
ΔH, ΔS and ΔG were estimated to be 21.31 kJ/mol, -0.226 kJ/mol dan 111.259
kJ/mol respectively. The produced biodiesel properties including kinematic,
density, flash point, acid number, and carbon residue of biodiesel were 1.93 mm2
/s,
0.86 g/cm3
, 137 °C, 0.27 mg KOH/g, dan 0.22%, respectively. The reusability test
of the NiO/CaO/MgO catalyst showed that the catalyst is stable during 2 cycle with
the yield of biodiesel of 89.00 % at the first cycle dan drastically decreased to 51.95
% at the fourth cycle
PENGARUH PENAMBAHAN OKSIDA CUO TERHADAP KARAKTERISTIK CUO/TS-1 SEBAGAI KATALIS ALTERNATIF PADA REAKSI OKSIDASI BENZENA MENJADI FENOL
Get PDFTelah dilakukan sintesis dan karakterisasi katalis CuO/TS-1. Mula-mula TS-1 disintesis dengan proses hidrotemal, dilanjutkan proses impregnasi TS-1 dengan prekursor Cu(NO) 2 .3H O menghasilkan katalis CuO/TS-1. Katalis TS-1 dan CuO/TS-1 hasil sintesis dikarakterisasi dengan menggunakan FTIR, XRD, adsorpsi-desorpsi N 2 2 untuk mengetahui luas permukaan dan adsorpsi piridin untuk mengetahui sisi asamnya. Hasil karakterisasi dengan FTIR dan difraksi sinar-X menunjukkan bahwa kedua katalis hasil sintesis merupakan katalis berstruktur orthorombik dengan tipe MFI. Hasil analisa BET menunjukkan luas permukaan katalis yang semakin menurun dengan naiknya loading CuO Adanya CuO pada TS-1 juga dapat meningkatkan jumlah sisi asam Lewis pada katalis
PREPARATION, CHARACTERIZATION AND CATALYTIC ACTIVITY OF CuO/TS-1 ON BENZENE HYDROXYLATION REACTION
No full textCuO/TS-1 catalysts have been prepared and tested in the benzene hydroxylation. TS-1 was synthesized by hydrothermalmethod, while CuO/TS-1 was prepared by impregnation method using Cu(NO)2.3H2O as precursor. Catalysts werecharacterized by using X-ray diffraction (XRD), infrared spectroscopy (IR), and N2 adsorption-desorption techniques.The catalytic activity was tested in the hydroxylation reaction of benzene. The products were analyzed using gaschromatography. Catalyst characterization by XRD and IR techniques have showed that the catalyst structure was aMFI type of zeolite. XRD pattern have showed the orthorombic structure and indicated the presence of CuOaggregation. The results of the pyridine adsorption have found that the acidity of TS-1 and CuO/TS-1 were a Lewis acidand it’s increased with an increasing amount of CuO loading. The results of nitrogen adsorption analysis have showeddecreasing of surface areas of catalyst with increasing amount of CuO loading. The optimum conditions of benzenehydroxylation was observed by 1%CuO/TS-1 catalyst at 70 °C, reaction time 2 h and acetic acid as the solvent yielded27.6% of phenol with phenol selectivity was 75.5%
PENERAPAN PEMBELAJARAN BERBASIS MASALAH BERORIENTASI CHEMO-ENTREPRENEURSHIP PADA PRAKTIKUM KIMIA FISIKA
Get PDFTelah dilakukan penelitian dengan tema pembelajaran berbasis masalah berorientasichemo-entrepreneurship (CEP) yang bertujuan untuk meningkatkan kualitas dan hasilbelajar Praktikum Kimia Fisika. Metode penelitian meliputi tahap perencanaan, pelaksanaantindakan, observasi dan evaluasi, refl eksi tindakan, dan analisis data. Mahasiswa pesertamatakuliah Praktikum Kimia Fisika dibagi menjadi beberapa kelompok. Tiap kelompok terdiriatas 3-4 orang. Pertama dilakukan pretest untuk mengetahui kemampuan awal mahasiswa.Selanjutnya mahasiswa diberi Lembar Masalah untuk didiskusikan sebelum melakukanpraktikum. Pada saat praktikum, mahasiswa merumuskan jawaban dari masalah berdasarkanpengamatan dengan dibantu pengarahan dari dosen. Dosen juga memberikan pengarahantentang jiwa kewirausahaan yang terkait dengan bidang kimia dengan tujuan memberikantambahan wawasan kepada mahasiswa agar memiliki nilai tambah pada kompetensinya.Aktivitas mahasiswa diamati dan dicatat dalam lembar observasi. Mahasiswa memberikansolusi lengkap pada saat mengumpulkan laporan praktikum. Langkah ini diulang untuk materipraktikum berikutnya sampai akhir semester. Pada akhir semester dilakukan postes untukmengetahui tingkat pemahaman dan hasil belajar mahasiswa. Berdasarkan hasil analisisdata dapat disimpulkan bahwa metode pembelajaran ini dapat meningkatkan aktivitas belajarmahasiswa dan secara kuantitatif hasil belajar mahasiswa menunjukkan peningkatan dari65 menjadi 81,2 dan ketuntasan belajar juga meningkat dari 34% menjadi 100%.Kata kunci:pembelajaran berbasis masalah, chemo-entrepreneurship</strong
The Synthesis of Chitosan Polymer Membrane/pva as an Eco-friendly Battery for Alternative Energy Resource
Get PDFThe eco-friendly materials which have not commonly developed as energy storage alternative sources are solid electrolytes. Chitosan is one of the natural polymer potentially used as the material of solid electrolytes. The purpose of this study is to determine the conductivity value of chitosan polymer's electrolytes-PVA-glutaraldehyde-NH4Br by varying amount of chitosan and ammonium bromide salt (NH4Br). The polymer electrolyte membrane was made using phase inversion method. Electrolyte polymer is made by mixing chitosan, PVA, glutaraldehyde, and NH4Br to become homogenous liquid and then printed it in petri dish. Polymer electrolyte with chitosan variation of 2; 2.4; 2.8 and 3.2 g has highest ionic conductivity of 1.4983 x 10-2 S/cm with the addition of 2.8 g that can be used as the optimum composition. The variations of salt (NH4Br) were 0; 0.2; 0.4; 0.6; 0.8 and 1 g has the highest ionic conductivity in the point of 2.4385 x 10-2 S/cm with the addition of 0.6 g. The characterization result of FTIR shows OH group at the wavenumber of 3362.02 cm-1, C-O group at 1740.43 cm-1, and C=N group at 1542.41 cm-1. Synthesized polymer can be used as a battery that has 0.43 V voltage
Synthesis of SrO.SiO2 Catalyst and Its Application in the Transesterification Reactions of Soybean Oil
No full textThe synthesis and characterization of SrO.SiO2 were carried out. The rice hull ash was utilized as a source for SiO2. The SrO.SiO2 was prepared by sol-gel technique, and the ratios of SrO:SiO2 were varied as 0:1, 1:0, 3:2, 2:4, and 2:7. The sol-gel was calcined at 800 oC for 4 hours. The result was characterized using XRD and FTIR. The diffraction pattern shows that the diffraction angle was shifted, and the intensity of the main peaks was increased. This research indicated that the crystallinity of SrO was improved at the higher SiO content. Further, a new peak was observed in the IR spectra at a wavenumber of 900 cm-1 indicating the appearance of new functional groups of the SrO.SiO2. The catalytic activity of SrO.SiO2 on transesterification reaction was optimized. The optimum condition was obtained at SrO.SiO2 of 2:7, reaction time of 30 minutes, reaction temperature of 65 oC, the amount of catalyst of 1 % w/v of reactants, and the biodiesel yield of 96.66 %. Copyright © 2017 BCREC Group. All rights reservedReceived: 11st November 2016; Revised: 28th February 2017; Accepted: 28th February 2017How to Cite: Widiarti, N., Suryana, L.A., Wijayati, N., Rahayu, E.F., Harjito, H., Wardhana, S.B., Prasetyoko, D., Suprapto, S. (2017). Synthesis of SrO.SiO2 Catalyst and Its Application in the Transesterification Reactions of Soybean Oil. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2): 299-305 (doi:10.9767/bcrec.12.2.804.299-305)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.804.299-305 </jats:p
Potensi minyak kemiri sunan (Reutealis trisperma) sebagai sumber energi terbarukan
Get PDFKebutuhan energi dunia semakin meningkat dari tahun ke tahun, dan saat ini banyak peneliti yang mencari energi dari sumber energi terbarukan, termasuk bahan bakar yang berasal dari tumbuhan. Salah satu tumbuhan yang menghasilkan biji yang mengandung minyak adalah kemiri sunan (Reutealis trisperma). Tulisan ini mengungkapkan potensi minyak kemiri sunan sebagai sumber energi terbarukan. Minyak kemiri sunan telah digunakan sebagai reaktan dalam sintesis biodiesel melalui reaksi esterifikasi dan transesterifikasi menggunakan H2SO4 dan NaOH sebagai katalis homogen dan CaO sebagai katalis heterogen. Minyak kemiri sunan juga berpotensi untuk dikembangkan menjadi biofuel (jet fuel), minyak pelumas, campuran bahan bakar. Selain biofuel, minyak kemiri sunan juga berpotensi digunakan sebagai bahan pengubah minyak nabati (bio-oil transformer) dan bahan tambahan biomaterial (biomaterial additive
The effectiveness of experiential learning on students' understanding of science and technology
Get PDFLearning through the experiential learning model encourages students to experiment dynamically and comprehensively. This research aims to see the effectiveness of the experiential learning learning model. This research uses a quantitative experimental research design as its methodology. The population of this study was fifth-grade students at Gugus Waru Elementary School, Parung District. Random sampling is the sampling strategy used in this research. Data collection techniques include tests, observation, and documentation. SPSS was used for data analysis. Validity, reliability, difficulty level of questions, and differentiation tests are tools used in research analysis. Furthermore, normality, homogeneity, hypothesis testing, N-Gain, and T-tests are prerequisite tests. The research results were concluded from the validation results of 88 material experts and received a very suitable category based on the evidence provided. Media expert validation scored 90 in the very appropriate category, while language validation obtained 64 in the appropriate category. The practical category is represented by the average of all validation findings, which is 80.6%. This makes this guidebook, which experts verified regarding content, language, and media, suitable for use.
Abstrak
Pembelajaran melalui model experiential learning mendorong peserta didik untuk bereksperimen secara dinamis dan komprehensif. Tujuan penelitian ini adalah untuk melihat efektivitas model pembelajaran experiential learning. Penelitian ini menggunakan desain penelitian eksperimen kuantitatif sebagai metodologinya. Populasi penelitian ini adalah peserta didik kelas V SD Gugus Waru Kecamatan Parung. Random sampling merupakan strategi pengambilan sampel yang digunakan dalam penelitian ini. Teknik pengumpulan data menggunakan tes, observasi dan dokumentasi. SPSS digunakan untuk analisis data. Validitas, reliabilitas, tingkat kesukaran soal dan tes pembedaan soal merupakan alat yang digunakan dalam analisis penelitian. Selanjutnya uji normalitas, homogenitas, uji hipotesis, N-Gain, dan uji T merupakan uji prasyarat. Adapun hasil penelitian disimpulkan dari hasil validasi ahli materi sebanyak 88 orang dan mendapat kategori sangat sesuai berdasarkan bukti-bukti yang diberikan. Validasi ahli media memperoleh skor 90 dengan kategori sangat sesuai, sedangkan validasi bahasa memperoleh skor 64 dengan kategori sesuai. Kategori praktis diwakili oleh rata-rata seluruh temuan validasi yaitu sebesar 80,6%. Hal ini menjadikan buku pedoman yang telah diverifikasi oleh para ahli dari segi isi, bahasa dan media ini layak untuk digunakan.
Kata Kunci: media audio visual; model experiential learning; pemahaman konsep IPA
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