Analisa Sifat Kemagnetan Polimer Poliethylen Glycol (PEG-4000)-coated Nanopartikel Magnetite Fe3O4 Menggunakan Vibrating Sample Magnetometer (VSM)

Iron oxide (Fe3O4) nanoparticles have been synthesized using coprecipitation method. Characterization of the magnetic properties of iron oxide (Fe3O4) nanoparticles using Transmission Electron Microscopy (TEM) shows a loop hysteresis curve on Fe3O4 magnetite nanoparticles with a value of Mr 7.7 emu/g at 0 kOe field, Ms 68.2 emu/g at an external field 14 ,61 kOe. A low Mr value or close to zero indicates that the Fe3O4 nanoparticle material is softmagnetic. Fe3O4 nanoparticles that had been modified with PEG-4000 polymer showed a Ms value of 55.7 emu/g in a 14 kOe field, an Hc coercivity field of about 60 Oe, and a Mr. 6.3 emu/g value in a 0 kOe field. The smaller the particle size, the more likely the material has a single magnetic domain. The smaller the sample particle size, the smaller the remanent magnetization value. The smaller the value of remanent magnetization, the residual magnetization that is still possessed by a material/sample when it is not affected by an external magnetic field is also greater

Analisa Sifat Kimia Fisik Fluida dan Perkiraan Temperatur Reservoir Geotermal di Kabupaten Minahasa Selatan

 The presence of geothermal potential in an area is indicated by the presence of surface manifestations such as hot springs, fumaroles, mud pools, steaming ground, warm ground, geysers, silica deposits, and other manifestations. Chemical and physical analysis of these manifestations can explore the value of subsurface characteristics such as reservoir type, temperature and pressure of reservoir rock formations, as well as the chemical properties of the fluid. The South Minahasa Regency which is the target of the research has geothermal manifestations such as hot springs, steaming ground, silica deposits, and others. The study was conducted to analyze the characteristics of the fluid using geochemical methods and to estimate the temperature of the geothermal reservoir in the manifestation area in South Minahasa Regency. Geothermal manifestation in Pinaesaan village, South Minahasa Regency is a type of chloride fluid. This shows that the geothermal area is a high temperature zone and has a high permeability zone. Geothermal fluid in Pinaesaan village, South Minahasa Regency is in the area of ​​partial equilibrium waters, which indicates that the fluid is not in a state of equilibrium. This is because the fluid has been mixed with surface water. The hot springs in Pinaesaan village are estimated to be an outflow zone from the geothermal system in the area. The estimated temperature of the geothermal reservoir in Pinaesaan Village using a silica quartz geothermometer calculation is 191°C

Pengaruh Penerapan Video Pembelajaran Melalui Google Classroom Pada Materi Larutan Elektrolit dan Non Elektrolit Terhadap Hasil Belajar Siswa di SMA N 1 Langowan

The purpose of this study was to determine the effect of the application of learning videos through Google Classroom on the learning outcomes of X Mipa 4 students at SMA N 1 Langowan. This research is a quantitative research using experimental method using One-Group pretest-posttest design. The population taken is all class X MIPA SMA N 1 Langowan, the sample consists of 1 class, namely X MIPA 4 as an experimental class, totaling 32 students. Data collection was done by giving a pretest before the learning process was carried out, and a posttest after the learning process. Data The results obtained in the form of the difference between the pretest and posttest in the experimental class are 40.4 and the average pretest is 47.7, while the posttest average is 88.1. get that the data is normally distributed. Furthermore, the test through t-test, the results obtained between the experimental class are significant, namely tcount = 18.60 > ttable = 1.998. Thus, it can be concluded that the Google Classroom learning media which contains video can affect student learning outcomes.Tujuan dari Penelitian ini adalah untuk mengetahui Pengaruh Penerapan Video Pembelajaran melalui Google Classroom  Terhadap Hasil Belajar siswa  X Mipa 4 di SMA N 1 Langowan. Penelitian ini adalah penelitian kuantitatif menggunakan metode experiment dengan menggunakan desain One-Group pretest-posttest design. Populasi yang diambil adalah seluruh kelas X MIPA SMA N 1 Langowan sampel terdiri dari 1 kelas yaitu X MIPA 4 Sebagai kelas eksperimen yang berjumlah 32 orang siswa. Pengambilan data dilakukan dengan memberikan pretest sebelum proses pembelajaran dilaksanakan, dan posttest setelah proses pembelajaran. Data Hasil penelitian yang diperoleh berupa selisih pretest dan posttest pada kelas eksperimen 40,4  dan rata-rata pretest yaitu 47,7, sedangkan rata-rata posttest yaitu 88.1, Sebelum di lakukan uji one sample t test terlebih dahulu di lakukan uji normalitas dan di dapatkan bahwa data terdistribusi normal. Selanjutnya uji melalui uji-t, hasil yang didapat antara kelas eksperimen signifikan yaitu thitung thitung = 18,60 > ttabel = 1,998.  Dengan demikian dapat disimpulkan  bahwa media pembelajaran Google Classroom yang berisikan Video dapat berpengaruh pada hasil belajar siswa

Aktivitas Antioksidan Ekstrak Etanol Batang, Daun Dan Akar Kopasanda (Chromolaena odorata L) dengan Metode ABTS (2,2’- azino - bis (3-etilbenzotiazolin -6- asam sulfonat)

Kopasanda (Chromolaena odorata L.) is a plant that contains flavonoid compounds that can act as antioxidants. This study aims to determine the antioxidant potential of the ethanol extract of the stems, leaves and roots of kopasanda by looking at the IC50 value. The stems, leaves and roots of Kopasanda were extracted by maceration using 70% ethanol as solvent. The results of the antioxidant activity test using the ABTS method (2.2'- azino - bis (3 - ethylbenzothiazoline - 6- sulfonic acid) showed a very strong antioxidant activity with an IC50 value of 11.5380 g/ml leaves, 31.161 g/ml stems and 36,860 roots. g/ml with positive control of quarcetin obtained IC50 value of 1.698 g/ml. Based on these results, it can be concluded that the stems, leaves and roots of the encounter have very strong antioxidant activity against ABTS free radicals (2,2'- azino - bis (3 - ethylbenzothiazoline). - 6- sulfonic acid)

Karakterisasi material mesopori Ni/MCM-41 dan pengaruh penambahan logam nikel terhadap tingkat keasaman material

Mesoporous material MCM-41 cannot be used directly as a catalyst, so need to be added metals or nonmetals to create an acidic site. Nickel is a Lewis acid metal because it is able to accept lone pairs of electrons from ligands to form complex compounds. The purpose of this study was to produce mesoporous material Ni/MCM-41 and to see the effect of the addition Nickel metal to the acidity level of mesoporous material Ni/MCM-41.Tthe ion exchange method is used to produce Ni/MCM-41 and the gravimetric method to test the acidity of the material. The MCM-41 used for Ni/MCM-41 synthesis has an x-ray diffraction pattern with a hexagonal structure that is identical with the MOC researchers results. BET results is showed the type IV of the Langmuir adsorption isotherm with a surface area of ​​Ni/MCM-41 material 775.9 m2/g, pore volume 0.81 cc/g and pore radius 15.2 Å. TEM characterization shows the morphological shape of Ni/MCM-41 in the form of hexagonal structure. The acidity test results of Ni/MCM-41 material have a higher acidity level compared to MCM-41. Based on the research data, it can be concluded that Ni/MCM-41 has a morphological form with a hexagonal structure, has a large surface area and has a pore size classified as mesoporous material and has a higher acidity level than the MCM-41 synthesized.Material mesopori MCM-41 tidak dapat digunakan langsung sebagai katalis, sehingga perlu ditambahkan logam atau bukan logam untuk menciptakan situs asam.  Nikel merupakan logam yang bersifat sebagai asam Lewis karena mampu menerima pasangan elektron bebas dari ligan untuk membentuk senyawa kompleks. Tujuan penelitian ini adalah untuk menghasilkan material mesopori Ni/MCM-41 dan melihat pengaruh penambahan logam Nikel terhadap tingkat keasaman material mesopori Ni/MCM-41. Metode yang digunakan yaitu metode pertukaran ion untuk menghasilkan Ni/MCM-41 dan metode gravimetri untuk uji tingkat keasaman material. MCM-41 yang digunakan untuk sintesis Ni/MCM-41 memiliki pola difraksi sinar-x dengan struktur heksagonal yang identic dengan hasil dari peneliti MOC. Hasil BET menunjukkan isotherm adsorpsi Langmuir tipe IV dengan luas permukaan material Ni/MCM-41 sebesar 775,9m2/g, volume pori sebesar 0,81 cc/g dan jari-jari pori sebesar 15,2 Å. Karakterisasi TEM menunjukkan bentuk morfologi Ni/MCM-41 berbentuk struktur heksagonal. Hasil uji tingkat keasaman material Ni/MCM-41 memiliki tingkat keasaman lebih tinggi dibandingkan dengan MCM-41. Berdasarkan data hasil penelitian tersebut maka dapat disimpulkan bahwa Ni/MCM-41 memiliki bentuk morfologi dengan struktur heksagonal, memiliki luas permukaan yang cukup besar serta memiliki ukuran pori yang tergolong material mesopori dan memiliki tingkat keasaman yang lebih tinggi dibandingkan dengan MCM-41 hasil sintesis

Analisis pengaruh penambahan ion H+ pada sintesis material mesopori Al-MCM-41 menjadi H-MCM-41

The synthesis of mesoporous Al-MCM-41 material made into H-MCM-41 has been done by mixing 5 grams of Al-MCM-41 synthesis into 100 ml of 0.5 M NH4Cl solution, then filtered and washed and dried in an oven at temperature 80 oC for 24 hours. The acid sites contained in the mesoporous material of H-MCM-41 are the Brønsted acid sites (B) and Lewis acid sites (L). The mesoporous material of H-MCM-41 synthesis shows morphological form of hexagonal pore such as honeycomb. It also makes clear that CTAB as a pore structure steering agent has succeeded in forming a hexagonal phase pore from mesoporous H-MCM-41 synthesized material. The size of the pore diameter of the mesoporous material of H-MCM-41 synthesis was 2.88 Å measured using a measuring ruler based on the scale of the resulting image analysis using TEM.Sintesis material mesopori Al-MCM-41 dibuat menjadi H-MCM-41 telah dilakukan dengan cara mencampur sebanyak 5 gram Al-MCM-41 hasil sintesis ke dalam 100 ml larutan NH4Cl 0,5 M, kemudian disaring dan dicuci serta dikeringkan dalam oven pada suhu 80 oC selama 24 jam. Situs asam yang terkandung pada material mesopori H-MCM-41 adalah situs asam Brønsted (B) dan situs asam Lewis (L). Material mesopori H-MCM-41 hasil sintesis menunjukkan bentuk morfologi berupa pori heksagonal seperti sarang lebah (honeycomb). Hal ini juga memperjelas bahwa CTAB sebagai bahan pengarah struktur pori telah berhasil membentuk pori fasa heksagonal dari material mesopori H-MCM-41 hasil sintesis. Ukuran diameter pori dari material mesopori H-MCM-41 hasil sintesis adalah 2,88 Å diukur menggunakan mistar ukur berdasarkan skala gambar hasil analisis menggunakan TEM

Sintesis dan karakterisasi material mesopori MCM-41 menggunakan TMAOH dan garam anorganik K2SO4

The MCM-41 synthesis has been performed starting from the dissolution stage of cetyltrimethylammonium bromide (CTAB) as a pore mold, then added tetramethylammonium hydroxide (TMAOH) and sodium sulfate salt (K2SO4) to improve the stability of the material. The crystallization process is carried out by adding sodium silicate and sodium aluminate dripwise into the solution. Decrease in pH of the solution was done by adding sulfuric acid (H2SO4 50%). The hydrothermal process is then carried out at 90°C for 36 hours, then washed, dried and calcined at 540°C. MCM-41 synthesis results were characterized using XRD, FTIR and TEM. The results showed that MCM-41 was successfully synthesized with a high degree of crystallography with 48Å lattice parameter size and had a uniform hexagonal pore structure.Sintesis MCM-41 telah dilakukan mulai dari tahap pelarutan cetyltrimethylammonium bromide (CTAB) sebagai cetakan pori, kemudian ditambahkan tetramethylammonium hydroxide (TMAOH) dan garam sodium sulfate (K2SO4) untuk meningkatkan stabilitas material. Proses kristalisasi dilakukan dengan menambahkan natrium silikat dan natrium aluminat tetes demi tetes ke dalam larutan. Penurunan pH larutan dilakukan dengan menambahkan larutan asam sulfat (H2SO4 50%). Selanjutnya dilakukan proses hidrotermal pada suhu 90°C selama 36 jam, kemudian dicuci, dikeringkan dan dikalsinasi pada suhu 540°C. MCM-41 hasil sintesis dikarakterisasi menggunakan XRD, FTIR dan TEM. Hasil penelitian menunjukkan MCM-41 berhasil disintesis dengan tingkat kristanilitas yang tinggi dengan unukuran parameter kisi sebesar 48 Å dan mememiliki struktur pori heksagonal yang seragam

Penilaian Gaya Belajar Model Honey-Alonso Mahasiswa Kimia FMIPA UNIMA

The Honey-Alonso model consists of 4 LS concepts namely Active Style (AS), Reflective Style (RS), Theoretical Style (TS), and Pragmatic Style (PS). The LS questionnaire consists of 80 statements, each LS has 20 statements. Test the validity of the instrument with SPSS 21 on the Scale – Reliability Analysis menu and the output is shown in the Item – Total Statistics  – Corrected Item-Total Correlation table.The results of 58 respondents obtained AS = 9 (45%), TS = 18 (90%), RS = 13 (65%), and PS = 13 (65%) with a consistent reliability coefficient. The assessment is based on the total individual score for each LS and is converted to a z-score using the NORMDIST excel formula. In the range of normal distribution values are identified in 5 categories namely Very Good (VG), Good (G), Enough (E), Less (L), and Very Poor (VP). The results of the assessment are a combination of 17 typical learning styles. There are 41 respondents who have a strong learning style and 17 respondents who have a weak learning style. Learning styles need to be known by students as early as possible so they can improve it. A strong learning style can increase their learning achievement.Model Honey-Alonso terdiri dari 4 konsep GB yakni Gaya Aktif (GA), Gaya Reflektif (GR), Gaya Teoritik (GT), dan Gaya Pragmatik (GP). Kuesioner GB terdiri dari 80 pernyataan, setiap GB memiliki 20 pernyataan. Uji validitas instrumen dengan SPSS 21 pada menu Scale – Reliability Analysis dan output terlihat pada tabel Item-Total Statistics – Corrected Item-Total Correlation. Hasil dari 58 responden diperoleh GA = 9 (45%), GT = 18 (90%),  GR = 13 (65%), dan GP = 13 (65%)  dengan koefisien reliabilitas yang konsisten. Penilaian didasarkan pada total skor individu setiap GB dan dikonversikan ke z-score menggunakan rumus excel NORMDIST. Dalam rentangan nilai distribusi normal diidentifikasi dalam 5 kategori yakni Sangat Baik (SB), Baik (B), Cukup (C), Kurang (K), dan Sangat Kurang (SK). Hasil penilaian terdapat kombinasi 17 tipikal gaya belajar. Terdapat 41 responden yang memiliki gaya belajar yang kuat serta 17 responden yang memiliki gaya belajar yang lemah. Gaya belajar perlu diketahui oleh mahasiswa sedini mungkin supaya mereka dapat meningkatkannya. Gaya belajar yang kuat dapat meningkatkan prestasi belajar mereka

PERENGKAHAN MINYAK SAWIT MENGGUNAKAN KATALIS PELET CAMPURAN H-MCM-41 DAN Ni-MCM-41

Catalitic cracking of palm oil using the mixture of H-MCM-41 and Ni/MCM-41 pellets as catalyst has been performed. MCM-41 was started from the dissolution of CTAB, then added TMAOH and K2SO4 were added to improve the stability of the material. Crystalization process was done by adding of sodium silicate and sodium aluminate into the solution, and then 50% H2SO4 was added to decrease pH of the solution. Further that the hydrothermal process was done at 90 oC for 36 h, and then washed, dried, and calcined at 540 oC. A synthesized MCM-41 was characterized using XRD, FTIR, BET, and TEM. H-MCM-41 catalyst was obtained by soaking the MCM-41 into 0,5 M NH4Cl solution and then calcined. The Ni/MCM-41 was obtained by soaking the MCM-41 into 0,1 M NiCl2 solution then after drying it was reduced at 450 oC. In the cracking process, ratio of H-MCM-4: Ni/MCM-41 = 1:1, 1:3, 3:1,1:0 and 0:1 were used. Ratio of the catalyst of 3:1 produced the highest oil conversion, and this ratio was used to form a pellet catalyst. The catalytic cracking processes using the pellet resulted conversion value of 70.40% containing 12.77% of OLP with selectivity to biofuel of 3.48%. The biofuel analyses of GC resulted the gasoline like fractions of 21.66 %, kerosene like fraction of 64.39 %, and 13.95 % diesel like fraction