Jurnal Fisika Unand
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Identifikasi Batuan Reservoir Panas Bumi di Daerah Tambang Sawah, Lebong Provinsi Bengkulu Menggunakan Data Gravitasi Satelit GGMPlus dengan Inversi 2D
Get PDFThe Tambang Sawah geothermal field located in Lebong Regency, Bengkulu Province, is one of the geothermal energy potentials in Indonesia. The area is associated with tectonic activity in the bukit barisan mountain range which is indicated by the appearance of hot springs and fumaroles. This research uses Global Gravity Model (GGM) gravity data, in the form of Free Air Anomaly (FAA) data with a resolution of 220 metres and shuttle radar topography mission (SRTM2Gravity) as contemporary terrain correction data in the form of full scale gravity data. The FAA data was then subtracted from the full scale gravity data to obtain the complete Bouger anomaly (CBA). The CBA was subjected to spectrum analysis to determine the depth estimate and then separated to obtain regional and residual anomalies using the moving average method. There are three distribution patterns of anomaly distribution, namely low, medium and high. The results showed that on the CBA map, areas with moderate anomalies were thought to have geothermal reservoirs with densities < 2.53 g/cm3 different depths.Daerah tambang sawah terletak di Kabupaten Lebong Provinsi Bengkulu merupakan salah satu daerah dengan potensi energi panas bumi yang ada di Indonesia. Daerah ini berkaitan dengan aktivitas tektonik di pegunungan bukit barisan yang ditunjukan dengan kemunculan mata air panas dan fumarol. Tujuan dari Penelitian ini untuk mengetahui batuan reservoir panas bumi di tambang sawah, Lebong Provinsi Bengkulu. Penelitian ini menggunakan data gravitasi Global Gravity Model (GGM), berupa data Free Air Anomaly (FAA) dengan resolusi 220 meter dan shuttle radar topography mission (SRTM2Gravity) sebagai data koreksi medan modern berupa data fullscalegravity. Data FAA kemudian dikurangkan dengan data fullscalegravity untuk mendapatkan anomali bouger lengkap (ABL). ABL dilakukan analisis spektrum untuk mengetahui estimasi kedalaman kemudian dilakukan pemisahan untuk mendapatkan anomali regional dan residual menggunakan metode moving avarage. Terdapat 3 pola distribusi sebaran anomali yaitu rendah sedang dan tinggi. Pada anomali residual dilakukan 2 sayatan yang diduga adanya reservoir panas bumi. Hasil penelitian menunjukan pada peta ABL Daerah dengan anomali sedang diduga memiliki reservoir panas bumi dengan densitas < 2,53 g/ pada kedalaman yang berbeda
Natural Clay yang Dimodifikasi Nikel dan Aplikasi Katalitik Untuk Produksi FAME : Efek Support dan Prekursor Nikel
Get PDFThis study was conducted to investigate the use of nickel modified clay as heterogeneous catalyst for the production of fatty acid methyl ester (FAME) from crude palm oil (CPO). The catalyst was prepared by Ni2+- exchanged cation supported on clay under controlled conditions. The results of X-ray Fluorescence analysis (XRF) indicated that Ni2+- exchanged cation modified on support of clay. The results of X-ray Diffraction (XRD) analysis confirmed that support of clay with characteristic of kaolinite mineral. Effect of supports of clay (h-clay and c/h-clay) and effect of nickel precursors (nickel sulfate and nickel nitrate) on the catalytic performance of heterogeneous catalysts in the transesterification reaction of CPO were investigated. The obtained data showed that transesterification processes at oil/methanol ratio of 1 : 6, reaction temperature of 85 oC, catalyst/methanol ratio of 1 : 10, and reaction time of 4 h produced yield of 51,19% FAME, 1,9% FAME, 4,74% FAME, and 47,8% FAME for catalytic performance of h-clay, c/h-clay, h-clay/Ni-Sulfate and h-clay/Ni-Nitrate, respectively. Ni2+- exchanged cation supported on h-clay prepared using two different precursors, nickel nitrate indicating higher catalytic activity than nickel sulfate.This study was conducted to investigate the use of nickel modified clay as heterogeneous catalyst for the production of fatty acid methyl ester (FAME) from crude palm oil (CPO). The catalyst was prepared by Ni2+- exchanged cation supported on clay under controlled conditions. The results of X-ray Fluorescence analysis (XRF) indicated that Ni2+- exchanged cation modified on support of clay. The results of X-ray Diffraction (XRD) analysis confirmed that support of clay with characteristic of kaolinite mineral. Effect of supports of clay (h-clay and c/h-clay) and effect of nickel precursors (nickel sulfate and nickel nitrate) on the catalytic performance of heterogeneous catalysts in the transesterification reaction of CPO were investigated. The obtained data showed that transesterification processes at oil/methanol ratio of 1 : 6, reaction temperature of 85 oC, catalyst/methanol ratio of 1 : 10, and reaction time of 4 h produced yield of 51,19% FAME, 1,9% FAME, 4,74% FAME, and 47,8% FAME for catalytic performance of h-clay, c/h-clay, h-clay/Ni-Sulfate and h-clay/Ni-Nitrate, respectively. Ni2+- exchanged cation supported on h-clay prepared using two different precursors, nickel nitrate indicating higher catalytic activity than nickel sulfate
Alat Ukur Kadar Air Biji-bijian Secara Mobile Berbasis Internet Of Things Sebagai Indikator Kualitas Komoditas Barang Dagang
Get PDFResearch has been conducted on a mobile IoT-based moisture content measuring device as an indicator of the quality of cocoa beans, yellow coffee, and robusta coffee. Moisture content is extremely important in maintaining the quality of beans because it directly affects their quality, taste, aroma, shelf life, and safety for consumption. This device uses a Capacitive Soil Moisture Sensor to detect moisture content by measuring changes in capacitance caused by dielectric changes. The moisture measuring device consists of a Capacitive Soil Moisture Sensor as the moisture sensor, an ESP32 as the data processor, an LCD to display the moisture content percentage, an LED as an indicator of high moisture levels, and a Smartphone as a measurement database through Blynk. The device was tested by measuring the moisture content of three types of grain samples: cocoa beans, yellow coffee, and robusta coffee. Each sample consisted of 10 variations of moisture content measured using a comparison tool, the Cerra Tester. The average measurement error percentages were found to be 3.02% for yellow coffee, 3.12% for cocoa beans, and 3.35% for robusta coffee. From the researchresults, the designed tool is as expected and works well.Telah dilakukan penelitian tentang alat ukur kadar air biji-bijian mobile berbasis IoT sebagai indikator kualitas biji kakao, kopi kuning, dan kopi robusta. Alat ini menggunakan Capacitive Soil Moisture Sensor sebagai pendeteksi kadar air dengan cara mengukur perubahan kapasitansi yang disebabkan oleh perubahan dielektrik. Alat ukur ini terdiri dari Capacitive Soil Moisture Sensor sebagai sensor kadar air, ESP32 sebagai pengelolah data hasil ukuran sensor, LCD sebagai penampil persentase kadar air, LED sebagai indikator tingginya kadar air, dan Smartphone sebagai database pengukuran melalui Blynk. Alat yang telah dibuat diujikan dengan mengukur kadar air 3 jenis sampel biji-bijian yaitu biji kakao, kopi kuning, dan kopi robusta. Tiap sampel terdiri dari 10 variasi kadar air yang telah diukur menggunakan alat pembanding yaitu Cerra Tester. Didapatkan hasil pengukuran rata-rata persentase error pada kopi kuning sebesar 3,02% , biji kakao sebesar 3,12%, dan kopi robusta sebesar 3,35%
Desain Pengiriman Data Gambar Menggunakan Gelombang Cahaya Tampak dengan Sel Surya Sebagai Detektor Cahaya
Get PDFVisible Light Communication research that sends image data has not been widely published. Therefore, it is necessary to conduct an experiment on sending image data from a camera connected to an Arduino where the module process is run. In this study, image transmission uses pulse-width-modulation (PWM), namely 2-PWM and 4-PWM. On the transmitter side, it consists of an OV2640 camera sensor, laser and Arduino Uno R3 while on the receiver side it consists of a solar panel and Arduino Uno R3. A push button is used as a trigger to take a picture by the camera; the image file will be converted by Arduino into binary; the binary will be modulated by the frequency of the red laser that emits pulses to the solar panel. The solar panel will forward the signal to Arduino to be modulated back into the original binary. Binary data will be processed into image data back offline using a computer. The system can work at a maximum distance of 8 m when using the 2-PWM module technique and a maximum of 6 m when using 4-PWM. The size of the system performance is calculated from the bit-error-ratio (BER) value based on the binary data received at the receiver.Riset komunikasi cahaya tampak (Visible Light Communication) yang mengirimkan data gambar belum banyak dipublikasikan. Oleh karena itu perlu dilakukan eksperimen pengiriman data gambar dari kamera yang terhubung ke Arduino tempat proses modulasi dijalankan. Dalam penelitian ini, pengiriman gambar menggunakan pulse-width-modulation (PWM) yakni 2-PWM dan 4-PWM. Pada bagian transmitter, terdiri dari sensor kamera OV2640, laser dan Arduino Uno R3 sementara pada sisi receiver teridir dari panel surya dan Arduino Uno R3. Sebuah push button dijadikan pemicu untuk mengambil gambar oleh kamera; file gambar akan dikonversi oleh Arduino ke dalam biner; biner akan dimodulasi oleh frekuensi laser merah yang memancarkan pulsa menuju panel surya. Panel surya akan meneruskan sinyal ke Arduino untuk didemodulasi kembali ke biner yang asli. Data biner akan diproses menjadi data gambar kembali secara offline menggunakan komputer. Sistem dapat bekerja pada jarak maksimal 8 m saat menggunakan teknik modulasi 2-PWM dan maksimal 6 m saat menggunakan 4-PWM. Ukuran kinerja sistem dihitung dari nilai bit-error-ratio (BER) berdasarkan data biner yang diterima pada bagian receiver
Sintesis Kristalin Selulosa Berbahan Limbah Pelepah Pisang
No full textNanocrystalline cellulose (CNC) was successfully synthesized from banana sheath waste and demonstrated promising potential for applications in biocomposites, sustainable materials, and biomedical fields. This study aimed to produce CNC through an environmentally friendly chemical process while investigating the effects of bleaching temperature and acid concentration on CNC yield and properties, in accordance with ISO/TS 20477:2017. The process involved delignification using 17% NaOH at 100°C for 1.5 hours to remove lignin, followed by bleaching with 10% H₂O₂ for 1.5 hours at various temperatures (70°C–90°C) to enhance cellulose purity. Acid hydrolysis using H₂SO₄ at concentrations of 10%–30% was conducted at 45°C for 40 minutes to break down amorphous regions and form nanocrystalline structures. Chesson-Datta analysis revealed cellulose, hemicellulose, and lignin contents of 80.32%, 5.257%, and 3.26%, respectively. Optimal conditions were found at 80°C bleaching temperature and 10% acid concentration, yielding 2.5606 g of CNC. SEM-EDX analysis showed smooth fibrous morphology with 63.55% carbon and 35.83% oxygen content, while XRD analysis indicated particle sizes ranging from 8.76 to 24.12 nm, with an average of 14.25 nm.Nanokristalin selulosa (CNC) dari limbah pelepah pisang berhasil disintesis dan menunjukkan potensi besar untuk diaplikasikan dalam biokomposit, material berkelanjutan, dan bidang biomedis. Penelitian ini bertujuan untuk menghasilkan CNC dari limbah pelepah pisang melalui pendekatan kimia yang ramah lingkungan serta mengkaji pengaruh suhu bleaching dan konsentrasi asam terhadap massa nanoselulosa yang dihasilkan serta karakteristik nanoselulosa yang diperoleh sesuai dengan standar ISO/TS 20477:2017. Proses sintesis diawali dengan delignifikasi menggunakan NaOH 17% dengan suhu 100°C dengan waktu 1,5 jam untuk melarutkan lignin yang mengikat serat selulosa. Kemudian dilakukan bleaching dengan H₂O₂ 10% selama 1,5 jam pada variasi suhu (70°C–90°C) untuk menghilangkan residu lignin dan meningkatkan kemurnian selulosa. Selanjutnya, dilakukan hidrolisis asam menggunakan variasi konsentrasi H₂SO₄ (10%–30%) pada suhu 45°C selama 40 menit guna memutus bagian amorf selulosa dan membentuk struktur kristalin berskala nano. Uji Chesson-Datta menunjukkan kandungan selulosa sebesar 80,32%, hemiselulosa 5,257%, dan lignin 3,26%. Kondisi optimum diperoleh pada suhu bleaching 80°C dan konsentrasi H₂SO₄ 10%, menghasilkan massa CNC sebesar 2,5606 g. Hasil Karakterisasi SEM-EDX menunjukkan morfologi berserat halus dengan kandungan karbon 63,55% dan oksigen 35,83%. Hasil analisis XRD menunjukkan ukuran partikel 8,76–24,12 nm dengan rata-rata 14,25 nm
Modifikasi Struktur Akseptor Zat Warna Tipe D-π-A Berbasis Ditiofen sebagai Sensitizer pada Sel Surya
Get PDFThis study aims to evaluate the effect of variations in the acceptor group of dithiophen-based type D-π-A dyes that are efficiently used as sensitizers in DSSC. The calculation uses the 16W Gaussian program with Density Functional Theory (DFT) and Time Dependent-DFT (TD-DFT) methods with the B3LYP/6-31G set base. Based on the results of the study, it is known that acceptor variations can affect the shift in absorption spectrum and bandgap values. The dye AT5 is predicted to have higher efficiency to be used as a sensitizer, because it has the smallest bandgap value and has a dipole moment value, as well as a larger wavelength. The smaller the bandgap value, the absorbedyu light will shift towards the red shift, and the electron excitation process will be easier. It can be concluded that dyes with cyanide formal acceptors can improve the efficiency of D-π-A type dyes as sensitizers in DSSC.Penelitian ini bertujuan untuk mengevalusi pengaruh variasi gugus akseptor zat warna tipe D-π-A berbasis ditiofen yang efisien digunakan sebagai sensitizer pada DSSC. Perhitungan menggunakan program Gaussian 16W dengan metode Density Functional Theory (DFT) dan Time Dependent-DFT (TD-DFT) dengan basis set B3LYP/6-31G. Berdasarkan hasil penelitian diketahui bahwa variasi akseptor dapat mempengaruhi pergeseran spektrum serapan dan nilai bandgap. Zat warna AT5 diprediksi memiliki efisiensi yang lebih tinggi untuk dijadikan sebagai sensitizer, karena memiliki nilai bandgap paling kecil dan memiliki nilai momen dipol, serta panjang gelombang yang lebih besar. Semakian kecil nilai bandgap maka cahaya yang diserap akan bergeser ke arah red shift, dan proses eksitasi elektron akan semakin mudah. Dapat disimpulkan bahwa zat warna dengan akseptor formil sianida dapat meningkatkan efesiensi zat warna tipe D-π-A sebagai sensitizer pada DSSC
Kajian Pengaruh PH dan Berat Kertas Terhadap Sintesis dan Karakteristik Silika Fiber dari Limbah Kertas HVS dan Kardus dengan Metode Sol Gel
Get PDFThe conversion of paper waste into silica fiber represents a strategic effort to reduce environmental pollution while adding value to HVS and cardboard waste. This study aims to examine the effect of pH and paper waste weight variations on the synthesis process and the characteristics of silica fiber produced using the sol-gel method. HVS and cardboard waste were used as cellulose sources, combined with sodium silicate and methanol. The variables tested included pH (3–7) and paper weight (8, 10, and 12 grams). Characterization involved density analysis, functional group identification using FTIR, and thermal stability assessment via TGA. The optimum condition for HVS waste was achieved at pH 5 with 8 grams, yielding a density of 1.8946 g/cm³, while for cardboard it was at pH 5 with 12 grams, yielding a density of 2.0228 g/cm³. Silanol and siloxane groups were identified in the FTIR spectra, and TGA results indicated good thermal stability at high temperatures. It can be concluded that variations in pH and paper waste weight significantly affect the formation and properties of the resulting silica fiber.Pengolahan limbah kertas menjadi silika fiber merupakan upaya strategis untuk mengurangi pencemaran lingkungan sekaligus meningkatkan nilai tambah limbah kertas HVS dan kardus. Penelitian ini bertujuan untuk mengkaji pengaruh variasi pH dan berat limbah kertas terhadap proses sintesis serta karakteristik silika fiber yang dihasilkan melalui metode sol-gel. Limbah kertas HVS dan kardus digunakan sebagai sumber selulosa, kemudian dikombinasikan dengan natrium silikat dan metanol. Variabel yang diuji meliputi pH (3–7) dan berat kertas (8, 10, dan 12 gram). Karakterisasi dilakukan terhadap densitas, gugus fungsi menggunakan FTIR, dan stabilitas termal menggunakan TGA. Hasil menunjukkan kondisi optimum untuk limbah HVS pada pH 5 dan berat 8 gram dengan densitas 1,8946 g/cm³, dan untuk kardus pada pH 5 dan berat 12 gram dengan densitas 2,0228 g/cm³. Gugus silanol dan siloksan terdeteksi pada spektrum FTIR, dan hasil TGA menunjukkan kestabilan termal yang baik hingga suhu tinggi. Dapat disimpulkan bahwa variasi pH dan berat limbah kertas memberikan pengaruh signifikan terhadap pembentukan dan sifat silika fiber yang dihasilkan
Implementasi Seismik Refraksi Metode Hagiwara untuk Pendeteksian Bidang Gelincir di Sempadan Sungai Daerah Perumahan Sungai Bangek
Get PDFThe rapid development in the riparian zone of the Bangek River, Koto Tangah District, Padang City, has the potential to increase the risk of geological hazards such as landslides. This study aims to identify the subsurface structure and the presence of slip surfaces in the riverbank area that is being developed into a residential zone, using the Hagiwara method. Data acquisition was carried out along two survey lines, oriented perpendicular and parallel to the river, with offsets of 40 m and 30 m, respectively, employing four geophones and a 10 kg hammer as the seismic source. The interpretation results from the first survey line indicate that the subsurface consists of unsaturated sand and weathered layers, with evidence of a slip surface at a distance of 0–18 m and depths ranging from 0.7–4 m. This slip surface is located within a permeable layer with a low seismic velocity (368.955 m/s), overlain by an impermeable layer with a higher velocity (642.508 m/s). Meanwhile, the second survey line reveals a relatively homogeneous structure composed of weathered layers with varying densities. The Hagiwara interpretation identifies a slip surface along the second refractor, indicating potential slope instability within the first layer characterized by a low seismic velocity (449.165 m/s), suggesting weaker rock compaction. The information regarding the presence and depth of the slip surfaces identified in this study provides an important reference for development planning to mitigate the potential risk of landslides in the Bangek River riparian zone.Pembangunan yang pesat di wilayah sempadan Sungai Bangek, Kecamatan Koto Tangah, Kota Padang, berpotensi meningkatkan risiko bencana geologis seperti tanah longsor. Penelitian ini bertujuan untuk mengidentifikasi struktur bawah permukaan dan keberadaan bidang gelincir pada area sempadan sungai yang dikembangkan menjadi kawasan perumahan menggunakan metode Hagiwara. Akuisisi data dilakukan pada dua lintasan, tegak lurus dan sejajar terhadap sungai, dengan offset masing-masing 40 m dan 30 m, menggunakan 4 geophone, dan palu seberat 10 kg sebagai sumber getaran. Hasil interpretasi pada lintasan pertama menunjukkan lapisan bawah permukaan terdiri dari pasir tak tersaturasi dan lapisan lapuk dengan indikasi bidang gelincir bidang gelincir pada jarak 0–18 m dengan kedalaman 0,7–4 m. Bidang gelincir ini terletak pada lapisan permeable berkecepatan rendah (368,955 m/s) di bawah lapisan impermeable berkecepatan tinggi (642,508 m/s). Lintasan kedua menunjukkan struktur cenderung homogen berupa lapisan lapuk dengan kerapatan yang berbeda. Interpretasi Hagiwara mengidentifikasi bidang gelincir di sepanjang refraktor lapisan kedua dengan potensi ketidakstabilan lereng pada lapisan pertama dengan kecepatan seismik rendah (449,165 m/s) yang menunjukkan tingkat kekompakan batuan yang lebih lemah. Informasi mengenai keberadaan dan kedalaman bidang gelincir yang berhasil diidentifikasi dapat menjadi acuan penting dalam perencanaan pembangunan untuk mengurangi potensi risiko longsor di wilayah sempadan Sungai Bangek
Biostimulant effect of a novel seawater-adapted strain of Scenedesmus almeriensis on garden geranium
No full textMicroalgae production requires substantial water resources. For this reason, different strategies are being investigated such as cultivating microalgae using wastewater or seawater. The goal of this study was to demonstrate the biostimulant effect of Scenedesmus almeriensis produced using both freshwater and seawater. This is the first time that the biostimulant capacity of seawater-produced Scenedesmus almeriensis has been investigated. The biostimulant capacity of the biomass was assessed in vitro using different bioassays and validated in vivo using Pelargonium × hortorum, commonly called zonal geranium or garden geranium. The in vitro results showed that S. almeriensis extracts significantly improved the germination index (GI) in watercress seeds and stimulated root formation in soybean seedlings compared to the water control. The in vivo trials confirmed that plants treated with S. almeriensis extracts experienced significant increases in the height, number of leaves and flowers, and dry weight of various organs, indicating an overall improvement in plant biomass and structural health. The results also revealed that the biomass produced in freshwater was more effective than that obtained in seawater, probably due to a lower accumulation of saline compounds that can reduce the biostimulant activity
