Measurement of Physicochemical Properties, Electrical and Thermal Conductivity of Wood Ash for Effective Soil Amendment

The ability of the soil to regulate heat energy is important for plant growth, soil texture and strength. Many agricultural soils are acidic in nature which tends to limit plant growth and microbial activity. Aside from agricultural lime, wood ash is used to amend physical and physicochemical properties of the soil. To maintain the soil hydraulic and physicochemical properties and to increase plant yield, it is important to know the physicochemical and physical properties of the ash used. The physiochemical and physical properties vary across various plant species. Ash samples from seven different plants were used for this study. The Horiba metre was used to measure the electrical conductivity, pH, Total Dissolved Solid (TDS) and salinity of the samples, while the Lees Disc apparatus was used to measure the thermal conductivity of the samples. The study revealed that moringa olieferra ash has the highest salinity, TDS and Electrical conductivity, while azadichta indica and tiobroma cacoa have least pH. Also, Kyah seleelygalisis and azadichta indica had the highest and lowest thermal conductivity respectively.

Kajian Energi Gelombang Laut Di Daerah Abrasi Serangai, Bengkulu Utara Melalui Pengamatan Tinggi Gelombang Laut

<p class="AbstractText"><span lang="EN-AU">The Serangai area, Batik Nau District, North Bengkulu has the highest average abrasion speed of 20 m/year. The abrasion could cause the coastal area to erode the coastline till several tens of meters. The purpose of this study was to determine the height of the ocean waves and to determine the energy of the ocean waves that has the potential to accelerate the abrasion process in the Serangai area. The research was carried out on November 5-7, 2018 in the Serangai beach area at a depth of 5 m using SBE 26 Plus Seagauge Wave equipment. The results showed that the observed wave height was between 0.8-1.6 m with a significant wave height (Hs) of 1.38 m. In addition, the wave period ranges from 5-11 s with a significant wave period (Ts) of 8.2 s. The result also shows that the maximum wave height of 1.6 m occurred on November 7, 2018 with maximum wave energy of 1800 J/m². This result can perhaps accelerate the abrasion process in the Serangai area. It can also be seen that the wave height in the Serangai region is higher than in several other areas in Indonesia. However, it is necessary to continue observing the wave height to see the seasonal variations in sea wave height in Serangai area.</span></p>

Pengukuran Indeks Ultraviolet Matahari dan Atenuasinya oleh Beberapa Bahan untuk Rekomendasi Waktu Aman Berjemur

Telah dilakukan penelitian tentang pengukuran indeks ultraviolet (UV) matahari dan atenuasinya oleh beberapa bahan. Penelitian ini dilatarbelakangi oleh kebutuhan berjemur di tengah terik matahari sebagai upaya meningkatkan imun tubuh ditengah Pandemi Covid-19. Indeks ultraviolet menjadi kunci dalam menentukan waktu yang tepat. Penelitian ini bertujuan memperoleh data distribusi indeks UV di suatu wilayah beserta atenuasinya untuk keperluan rekomendasi rentang waktu aman berjemur. Alat ukur yang digunakan berupa sensor indeks UV analog yang mengubah radiasi UV menjadi tegangan analog pada rentang 0 – 1 V. Nilai output dibaca menggunakan multimeter lalu dikonversi ke dalam UV indeks menggunakan tabel konversi bawaan produk. Pengukuran UV indeks dibagi menjadi tiga kondisi, pertama berdasarkan rentang waktu pada rentang waktu dari pukul 08.00 – 16.00 WIB, pengaruh tutupan awan, dan pengukuran UV indeks saat melawati beberapa bahan: kacamata transparan, kacamata riben, plastic kemasan, topi, dan kaos olahraga. Hasil penelitian menunjukkan distribusi indek UV berdasarkan rentang waktu berhasil diperoleh, tutupan awan menyebabkan penurunan indek UV sebesar 4 tingkat dan atenuasi Indek UV oleh beberapa bahan berhasil diperoleh. Berdasarkan sampel pengambilan data di Tinjomoyo Banyumanik Kota Semarang diperoleh waktu aman berjemur berada pada rentang sebelum Pukul 10.00 WIB dan setelah Pukul 14.00 WIB.

Klasifikasi Kanker Paru Paru menggunakan Naïve Bayes dengan Variasi Filter dan Ekstraksi Ciri GLCM

<p class="AbstractText">Telah berhasil dilakukan klasifikasi kanker paru-paru dari 120 data citra CT Scan. Pada penelitian, proses preposisi dimulai dengan variasi filtering yaitu low pass filter, median filter, dan high pass filter. Segmentasi yang digunakan yaitu Otsu Thresholding yang kemudian teksturnya akan diekstraksi menggunakan fitur Gray Level Co-occurrence Matrix (GLCM) dengan variasi arah sudut. Hasil dari ekstraksi GLCM dijadikan database yang akan menjadi dataset untuk pengklasifikasian citra menggunakan klasifikasi naïve bayes. Hasil dari penelitian dengan 12 buah variasi diperoleh hasil variasi terbaik adalah median filter dengan arah sudut GLCM 0° menunjukkan tingkat akurasi yang paling tinggi sebesar 88,33 %.</p>

Characterization of Left Ventricle Main Flow Axis Line Using Echodynamography

<span>Left ventricular (LV) blood flow analysis may play an essential role in evaluating cardiac function besides the classical analysis of wall motion. Echodynamography is an imaging method in which two-dimensional (2D) blood flow vectors are deduced by blood flow information obtained by color Doppler echocardiography. Echodynamography has provided useful information on the blood flow pattern in healthy and abnormal LV. The main flow axis line (MFAL) is defined as a maximum velocity magnitude of blood flow from the LV's apex to LV's outflow, which is a new hemodynamic parameter for cardiac assessment. The present study's objective is to compare blood flow patterns between healthy and abnormal LV by investigating the MFAL and its correlation to vorticity and velocity distribution on MFAL. This study enrolled 12 participants, four healthy volunteers, and eight abnormal patients. Echodynamography analyzed frame by frame Doppler image of apical three-chamber views. The results showed MFAL superimposed on vorticity mapping during ventricular ejection and MFAL path coincide with the irrotational flow of zero vorticity path, ω = 0. A significant difference was observed in the velocity distribution curve (VDC) on the MFAL during early, mid, and late systoles compared to healthy and abnormal LV. VDC showed the linear upward curve and the highest velocity magnitude during the early systole phase in healthy LV. In contrast with abnormal LV, VDC showed the downward convex curve and the highest velocity magnitude during mid systole phase. Furthermore, the gradient and slope angle of the VDC on the MFAL was compared. The result showed that the maximum gradient and slope angle were not significantly different between healthy and abnormal LV. In conclusion, the study of MFAL and the correlation to vorticity based on the Echodynamography computational program provides additional insights for representing a cardiac function, and thus, the clinical implications of MFAL warrant further investigation.</span>

Struktur Kecepatan Gelombang Geser (Vs) di Daerah Rawan Gerakan Tanah (Longsor) Jalan Lintas Kabupaten Bengkulu Tengah-Kepahiang

Shear wave velocity <em>(V_s)</em> structure at along of Central Bengkulu-Kepahiang crossline has been mapped. This research aims to identify the subsurface structure and to estimate the constituent material type of rock in landslide-prone areas (Central Bengkulu-Kepahiang crossline). Shear wave velocity structure on each site is obtained by the HVSR-inversion of 146 microtremor data (ambient noise recording of seismometer). <em>V_s</em> structure at the line mapped from the surface until to 30 meters of the depth. Groups of Vs are identified in class E (<em>V_s</em> &lt;180), Class D (180≤<em> V_s</em> &lt;360), Class C (360≤<em> V_s</em> &lt;760), and Class B (760≤<em> V_s</em> &lt;1500). The subsurface structure at the depth of 0 to 10 meters are dominated by stiff soil, very dense soil, and soft rock which has highly fractured and weathered rock properties. At the depth of 15 meters to 30 meters, the subsurface structure is dominated by hard rock but it is high potential or easy to fracturing and weathering like the properties of the rocks in areas that have landslides in the past. Based on <em>V_s</em> value, rock constituent materials are deposition of sand, clay, gravel and alluvium ranging from soft to relatively hard structures at the depth.

The Effects Of High Dose and Low Dose Protocols In Thorax’s CT Scan Image Quality

<p class="AbstractHeading">ABSTRACT</p><p class="AbstractText">The aim of this research was to evaluate the effects of two different dose protocols’ usage on image quality. This research was performed on three different CT Scanners using high dose and low dose protocols of thorax scan. Different exposure parameters were used, depending on each scanner’s setting. GE QA CT Scan phantom was used for image quality assessment. Image quality measured were CT number accuracy, uniformity and linearity, noise uniformity, spatial resolution and Contrast To Noise Ratio (CNR). CT Scan’s dose index, CTDIvol (Volumetric Computed Tomography Dose Index), was also measured to evaluate how these two protocols work in reducing radiation dose. The result showed that the usage of low dose protocols reduce the CTDIvol value at 85-91% compared to the high dose protocols, meanwhile most of the image quality parameters obtained from both protocols were still considered good. The CT number accuracy, uniformity, linearity and noise uniformity for all CT Scans were all still inside BAPETEN’s (Indonesia National Regulator Agency) threshold. There were 20-23% difference on the spatial resolution value measured from both protocols. The most significant difference came from CNR. The CNR obtained from high dose protocols were 65-93% higher than the one from low dose protocols. </p><p class="AbstractText">Keywords: contrast to noise ratio, CTDIvol, CT number, spatial resolution</p><p class="AbstractHeading">ABSTRAK</p><p>Penelitian ini mengevaluasi pengaruh penggunanaan protokol dosis tinggi dan protokol dosis rendah terhadap kualitias citra dan dosis khususnya pada pemeriksaan CT Scan thorax. Penelitian ini dilakukan pada 3 sampel CT Scan yang berbeda. Faktor eksposi yang digunakan berbeda untuk tiap scanner, bergantung pada setting yang terdapat pada scanner. Fantom yagdigunakan untuk menilai kualitas citra adalah fantom GE QA CT Scan. Adapun kualitas citra yang diukur adalah keseragaman, akurasi, dan linearitas CT number, keseragaman noise, resolusi spasial, serta <em>Contrast to Noise Ratio</em> (CNR). Sementara dosis radiasi yang diamati adalah CTDIvol (Volumetrik <em>Computed Tomography Dose Index</em>) yang tampil pada konsol. Hasil penelitian ini menunjukkan bahwa penggunaan protokol dosis rendah mampu mengurangi nilai CTDIvol sebesar 85-91% dibanding dengan protokol dosis tinggi, sementara sebagian besar parameter kualitas citra yang diukur masih dinilai baik. Nilai akurasi, keseragaman, dan linearitas CT number serta keseragaman noise pada protokol dosis tinggi dan dosis rendah, keseluruhannya masih dalam batas ambang BAPETEN. Terdapat perbedaan sebesar 20-23% pada nilai resolusi spasial yang terukur dari kedua protokol. Nilai CNR pada protokol dosis tinggi lebih baik dari pada protokol dosis rendah, dengan perbedaan yang cukup signifikan, yaitu 65-93%.</p><p class="AbstractText">Kata kunci: <em>contrast to noise ratio</em>, CTDIvol, <em>CT number</em>, resolusi spasial</p>

Analisis Tingkat Kegempaan Wilayah Jawa Timur berbasis Distribusi Spasial dan Temporal Magnitude Of Completeness (Mc), A-Value Dan B-Value

<p class="AbstractText">Distribusi spasial dan temporal dari parameter seismisitas yang terdiri dari <em>magnitude of completeness</em> (Mc), <em>a-value</em>, dan <em>b-value </em>telah dihitung sebagai upaya untuk menganalisis tingkat kegempaan wilayah Jawa Timur. Parameter tersebut dihitung berdasarkan data katalog gempa bumi <em>International Seismological Center</em> (ISC) dalam rentang waktu antara tahun 1980-2020. Tujuan dari penelitian iniadalah untuk menentukan parameter seismisitas dan distribusi spasial dan temporalnya sehingga proses deteksi dan peringatan dini gempa bumi di Jawa Timur dapat berjalan secara optimal. Parameter seismistas dihitung dengan menggunakan metode <em>Maximum Curvature</em> (MaxC). Metode MaxC dalam menentukan parameter seismisitas terdiri dari proses menentukan titik kelengkungan maksimum dengan menghitung nilai maksimum dari turunan pertama kurva distribusi Frekuensi-Magnitudo (FMD). Variasi parameter seismisitas kemudian dipetakan secara spasial dan temporal setiap sepuluh tahun dalam kurun waktu 50 tahun terakhir untuk melihat perubahan variasi parameter seismisitas. Hasil penelitian menunjukkan Mc-<em>value</em> 3,4 – 4,8; a-<em>value</em> 5,560 - 8,244; dan b-<em>value</em> (0,73 – 0,82 ± 0.13). Daerah yang memiliki <em>b-value</em> rendah (0,73 ± 0.13) berada di sekitar wilayah selatandai Jawa Timur. Wilayah ini diindikasikan sebagai daerah dengan pelepasan momen seismik yang tinggi dan memiliki akumulasi tingkat <em>stress</em> batuan yang tinggi. Mengetahui dan memahami hubungan antara parameter seismistas dan struktur tektonik dapat membantu kita untuk menentukan tingkat resiko bencana gempa bumi di wilayah Jawa Timur.</p>

Structure and Magnetic Properties Of Fe/Si Nanoparticles Prepared by High Energy Milling Process

The structure and magnetic properties of Fe/Si nanoparticle prepared by high energy milling process have been examined, focusing on the phase transition. Fe/Si nanoparticles were processed by high energy milling (HEM) for 10 hours to 50 hours with a weight per cent ratio of 9:1. Based on the X-ray diffraction (XRD) pattern, transmission electron microscope (TEM) observations, and vibrating sample magnetometer (VSM) analysis, the phase transition induced by HEM, were evidenced. The effect of structural state and the particle size on the magnetic properties such as magnetization was also studied. It was found that iron and iron oxides (-Fe2O3/ Fe3O4) phase were exhibited on all milled samples. The magnetization value of Fe/Si nanoparticles increased up to 20 hours with 142 emu/gr saturated magnetization and then decreased linearly with increasing milling time. Referring to the XRD result, this decline was initially caused by the iron oxide formation and magnetic interaction between iron and iron oxides nanoparticles. The phase and magnetic properties value changes related to the interaction mechanism between Fe atoms caused by interstitial occupied of Si atoms, particle size reduction, and oxidation process.

Pengaruh Temperatur Rendah pada Sifat Bending dari Pipa Komposit Epoxy dengan Penguatan Serat Jute

<p class="AbstractText">The experiment about the bending behavior of pipe composite based under the low-temperature treatment was carried out. As for the background of this research is that composite material become a suitable design with user need and it has behavior to substitute metal in engineering products. The research aims to investigate the effect of low temperature against to bending strength behavior of pipe from composite epoxy with jute fiber reinforcement. The low-temperature treatment was applied through an immersion process in dry ice as long as 60 minutes to produces a temperature of -33oC. The pipe composite was manufactured in lamination three layers of jute fabric using the vacuum injection molding process (VRTM). Then, the strength of the composite pipe was tested on the three-point bending method according to the ASTM D 790 standard. The testing results show that composite pipe with low-temperature treatment has a flexural strength average of about 76.559 MPa. Meanwhile, the compo-site pipe without treatment shows the strength of flexural average of about 52.435 MPa. They have the strength of flexural inclination is an average of 68%. In addition, the failures of composite in three-point bending test shows a shrank mode on the compression side and flat tearing at tension side due to the material becomes brittle. The conclusion that low-temperature treatment has an effective influence on the pipe composite mechanical properties.</p>