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Magnetic Susceptibility of Volcanic Soil on the Surface of Mount Singgalang, Sumatra Barat
Get PDFVolcanic soil is a part of interest for physical, chemical, and morphology studies of soil derived from volcanic ash, which is known to be fertile and is one of the most productive soils in the world. They are also known to have a high environmental carrying capacity, as evidenced by the dense population in the area around the volcano. The soil contains many minerals, one of which is magnetic minerals. However, there is no document so far that records the value of the magnetic susceptibility of volcanic soil on the surface of Mount Singgalang. This study aims to determine the abundance of magnetic minerals based on their magnetic susceptibility values. To achieve this goal, the rock magnetism method is applied with the Bartington magnetic susceptibility meter type MS2B sensor instrument. Magnetic susceptibility values can be used as initial characteristics to understand past volcanic processes and explain environmental changes. This method is very effective, inexpensive, sensitive, fast, and non-destructive. The results showed that the value of the magnetic susceptibility of volcanic soils varied with a value range of 93.3 - 352.5 (x10−8 m3/kg). Based on this value, it is assumed that the magnetic mineral properties are antiferromagnetic. The average frequency dependent susceptibility (χfd) (%) ranges from 0.831 - 2.090 %, indicating that the measured volcanic soil contains almost no superparamagnetic grains and is generally dominated by multi-domain grains
Fabrication of Polyaniline Thin Film Using Electrodeposition Method as Alcohol Sensor
Get PDFThe use of aliphatic alcohols such as methanol as an alternative renewable fuel in high-density engines can harm both the environment and human health. Polyaniline (PANi), a conductive polymer, has emerged as a solution to this problem because of its benefits as a sensor with relatively high conductivity. In this study, PANi was synthesized using a potentiostat electrodeposition method at a constant potential of -0.4 to +1.0 V at a scan rate of 100 mV/s, resulting in a thin film of PANi on the ITO surface. The formed PANi samples were used to determine the sensitivity level of the sensor to methanol at different concentrations. Morphological results of PANi deposited on the ITO surface were observed using SEM showing the shape of nanoparticles with an interconnected-sponge structure and a porous shape with a diameter of 35.3 nm. The PANI sample can be applied as a sensor material for detecting alcohol vapour in indoor air (at room temperature). The sensing measurement results show that the PANi-based sensor can detect methanol vapour at low concentrations up to 5 ppm. The higher the methanol concentration used, the higher the sensor sensitivity
Analisis Campuran Lapis Tipis Beton Aspal (LTBA) Menggunakan Bahan Tambahan Karet Alam SIR 20 Terhadap Karakteristik Marshall
Get PDFKaret alam SIR 20 merupakan hasil produksi bahan setengah jadi dari perusahaan karet. Saat ini, volume karet alam SIR 20 hasil produksi perusahaan karet cukup melimpah dengan menurunnya harga karet di pasar global. Pemanfaatan material karet alam SIR 20 dalam campuran Lapis Tipis Beton Aspal (LTBA) pada lapis permukaan (surface) pada struktur perkerasan jalan raya diharapkan mampu membantu menyelesaikan permasalahan tersebut. Penambahan bahan karet alam dalam campuran aspal ini menggunakan metode kering dengan persentase penambahan karet sebanyak 0%, 6%, 8% dan 10% terhadap berat aspal. Hasil dari penelitian menunjukkan bahwa variasi persentase penambahan karet SIR20 dalam campuran LTBA meningkatkan nilai karaktersitik marshall pada campuran aspal. Hasil optimum yang terbaik dari setiap kadar persentase ditunjukkan pada penambahan kadar karet 8% dan kadar aspal 5,8% dengan nilai stabilitas 2121,09 kg; nilai flow 3,80 mm; nilai VIM 3,82%; nilai VMA 17,25%; nilai VFA 77,91%; MQ 558,18 kg/mm
Pemodelan Estimasi Biaya Kontingensi Pada Proyek Konstruksi Jalan Raya Berbasis Metode Analisis Risiko
Get PDFKetidakpastian risiko pada proyek konstruksi jalan raya mendorong perkiraan biaya kontingensi di estimasi secara tradisional berdasarkan penilaian subyektif seperti 5-10% dari biaya yang diperkirakan dengan mempertimbangkan proyek sejenis yang pernah dikerjakan. Metode tersebut secara ilmiah tidak bisa diterima dan sulit untuk dipertahankan keakurasiannya. Studi ini mengusulkan metode pengembangan model biaya kontingensi dari perspektif pemilik proyek yang dapat mengakomodasi penilaian subjektif berdasarkan risiko. Identifikasi variabel risiko diperoleh dari survei pendahuluan, wawancara, penyebaran kuesioner dan studi literatur, sedangkan perhitungan pemodelan biaya kontingensi menggunakan simulasi Monte Carlo. Hasil penelitian menunjukkan bahwa perkiraan biaya kontingensi rata-rata adalah 8,92% dari rencana anggaran proyek. Tingkat kesalahan pengujian model adalah 0,21% dari batas kesalahan yang diijinkan dan hasil validasi menunjukkan bahwa nilai analisis prediktif berada dalam akurasi 20% dibandingkan dengan biaya kontingensi yang sebenarnya
Analisis Risiko Gempabumi di Sumatera dengan Cauchy Cluster Process
Get PDFSumatra is one of the prone areas in Indonesia to earthquakes. This condition is due to its geography which is traversed by active faults, subduction zones, and volcanoes. In this study, the distribution of earthquakes occurrences in Sumatra is modeled by considering the effects of spatial trends due to subduction zones, active faults, and volcanoes and also considering the cluster effects caused by mainshock and aftershock activities using the inhomogeneous Cauchy cluster process. In spatial trend modeling, there are indications that there is multicollinearity issue characterized by a high correlation among geographical factors, so this study considers ridge regularization to overcome this problem. The results of data exploration show that the earthquakes in Sumatra are not homogeneous and form clusters due to geological factors such as the presence of volcanoes, subduction zones, and active faults. Earthquake intensity modeling with ridge regularization produces an AIC value of -2280648 which is smaller than the model without regularization. The Cauchy cluster model by considering ridge regularization resulted in an estimated number of 63 mainshocks with a standard deviation of aftershocks around the mainshocks of 17.685 km. The closer a location to a fault, the risk of an earthquake occurring at that location increases by 1.6972 times. The closer a location to a subduction zone, the risk of an earthquake at that location increases by 1,25899 times, and the closer a location is to a volcano, the risk of an earthquake at that location increases by 1.55910 times
A New Approach to Estimate the Potential Assets Loss due to Dam-Break Event in Indonesia
Get PDFA dam break is a devastating natural catastrophe that can lead to huge losses. In general, the severity of a disaster can be determined by the amount of damage it causes. The greater the loss, the more severe the disaster and vice versa. However, determining the potential asset loss as a result of a disaster is a challenging task. So far, there is no method for calculating potential asset loss that is specifically made for dam-break disasters. Therefore, this study proposes a new approach in calculating the potential asset loss for a dam-break. In this study, the potential asset loss is calculated by considering four factors, namely the Potential Loss of Lives (PLOL), Potential Loss of Incomes (PLOI), Potential Loss of Houses Damage (PLOHD), and Potential Loss of Productive Land (PLOPL). In addition, the study calculates the potential asset loss of the Ketro Dam dam-break disaster. Based on the evaluation results, the PLOL might reach Rp. 26,419,715,661. PLOI might reach maximum value of Rp. 1,185,600,000. PLOHD might reach maximum value of Rp. 4,255,325,000. And lastly , PLOPL might reach maximum value of Rp. 25,375,080,780. Thus, the potential asset loss for the Ketro Dam dam-break disaster based on the analysis can reach Rp. 57,235,721,441 or USD 4,026,304
Formulation of Gambir Extract Nanoemulgel with Maggot Oil as Oil Phase
No full textAbstractGambir is the result of extraction from the leaves of the gambier plant (Uncaria gambir Roxb)which contains polyphenolic compounds. The polyphenolic compounds contained in this gambier extract are catechins which act as antimicrobials and antioxidants. The nanoemulgel formulationin this study used an active ingredient, namely gambir extract (Uncaria gambir Roxb) with a concentration of 9% containing flavonoids which have good antibacterial activity. In the manufacture of oil phase nanoemulsions from the use of 1% Black Soldier Fly (BSF) maggot oilwhich has characteristics such as VCO which is commonly used. Emulsification method wascarried out using a magnetic stirrer with a spontaneous mixing technique. Several nanoemulsion characterization tests using the Particle Size Analyzer (PSA) included particle size, polydispersityindex, and zeta potential results obtained according to the nano criteria, namely 382.27 ± 72.28 nm, 0.29 ± 0.14, respectively. and -0.57 ± 1.28 mV. In the nanoemulgel formulation of gambir extract, several tests were carried out such as organoleptic, homogeneity, pH (6.23 ± 0.31),dispersion (5.83 ± 0.15 g.cm/s), and adhesion (7.33 ± 0.90 s) that meet the criteria for nanoemulgel preparations.Keywords: Gambir extract; maggot oil; nanotechnology
Kampanye Edukasi Dengan Media Berbasis Ilustrasi untuk Mendukung Program Pemerintah menghadapi Masalah Endemi
Get PDFAbstrak— Pada tahun 2022, Pemerintah Indonesia sedang mewacanakan perubahan status pandemi COVID-19 menjadi endemi. Bedasarkan alasan tersebut, Strategi yang tepat dibutuhkan untuk memberikan edukasi bagi seluruh komponen masyarakat. Satgas Covid-19 bermitra dengan Institut Teknologi Sepuluh Nopember merancang kampanye berbasis ilustrasi yang telah terbukti mampu meningkatkan atensi dan mempermudah pemahaman audiens terhadap konten edukasi, sehingga komunikasi dapat berjalan lebih efektif. Kampanye berbasis media ilustrasi diharapkan dapat memberikan dampak yang signifikan dalam rangka menyampaikan berbagai pesan edukasi kepada masyarakat.Abstract—In 2022, The Indonesian government is discussing the discourse of the status change of the Covid-19 pandemic to endemic. For this reason, the Government needs the right strategy of socialization and education to touch all levels of society in dealing with the endemic. The Covid-19 Task Force partnered with the Sepuluh Nopember Institute of Technology to design an illustration-based campaign that has been proven to increase attention and facilitate audience understanding of educational content, so that communication can run more effectively. Illustrated media-based campaigns are expected to have a significant impact in conveying various educational messages to the public.
Modal Split Model dengan Metode Stated Preference Antara Suroboyo Bus dangan Kendaraan pribadi
No full textAngkutan umum yang tepat waktu dan nyaman tanpa terkendala macet menjadi daya tarik yang besar bagi masyarakat. Untuk menarik minat masyarakat di Kota Surabaya menggunakan angkutan umum, pemerintah kota Surabaya telah menyediakan Suroboyo Bus sebagai moda transportasi umum. Penelitian ini bertujuan untuk mengetahui seberapa besar minat masyarakat di kota Surabaya untuk ber alih moda dari moda semula ke Suroboyo Bus menggunakan metode Stated Preference, dengan mengubah atribut biaya dan waktu perjalan, dengan jumlah responden 120 diperoleh hasil bahwa ada 99 orang yang memutuskan untuk berpindah ke Suroboyo Bus dan 21 lainnya tetap menggunakan moda transportasi lain baik sepeda motor maupun kendaraan lain.