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Burning Rate Constants and Microexplosion Phenomena Measurements of Droplet Combustion Fidari Rosyadi, Basthiyan Sidqi; Wardana, I Nyoman Gede Wardana; Shy, Shenqyang (Steven)
Rekayasa Mesin Vol 5, No 1 (2014)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

This study investigates experimentally droplet combustion in a quiescent atmosphere using diesel oil (DO), biodiesel oil (BO), and sunflower oil (SO). Symmetrically spherical droplets with diameters varying from 0.3 mm to 0.6 mm are generated by a home-built piezoelectrically-driven droplet generator. Before a run, the small droplet is suspended at the intersection of two very fine horizontally-positioned, perpendicularly-aligned ceramic fibers of 20 µm in diameter. A run begins at a time when a diffusional flame is just established to envelop the suspended droplet using an electrically-controlled and automaticallyremoved heating device. A high-speed camcorder is used to record the time evolution of droplet burning process. Results show that after flame envelope the droplet where initial diameter (d ) is determined, DO and BO droplet instantaneous diameters (d) just shrink with increasing time, where plot for d 0 law give linear slope indicate that DO and BO can be assumed as singlecomponent fuel with burning rate constants value, but SO which is multicomponent fuels, give two kinds slope from d -law plot indicate that there are two value burning rate constants, namely K 1 2 for first stage of burning rate constant and K 2 for second stage of burning rate constant.Keywords: Droplet combustion, Burning Rate Constant, Microexplosion.
Peningkatan Kualitas Bahan Bakar Biogas Melalui Proses Pemurnian Dengan Zeolit Alam Hamidi, Nurkholis; Gede Wardana, I Nyoman; Widhiyanuriyawan, Denny
Jurnal Rekayasa Mesin Vol 2, No 3 (2011)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Biogas from digester consists primarily of methan (CH4) and carbondioxyde (CO2). Trace components that are often present in biogas are water vapor (H2O) , hydrogen sulfide (H2S),hydrocarbons (HC), ammonia (NH3, oxygen (O2), carbon monoxide (CO) and nitrogen (N2). In order to improve the quality of biogas, a cleaning process to remove the trace components and an upgrading process to adjust the calorific value are needed. A number of techniques have been developed to remove the trace components from biogas. In this experiment, however, chemical absorption of CO2 and H2S by solid zeolite in a plastic bag was experimentally investigated. The solid zeolite was activated by heat treatment and KOH. Absorption characteristics were examined. Test results revealed that the solid zeolite used were effective in adsorbed CO2 and H2S in biogas, creating CH4 enriched fuel. Absorption capability was transient in nature. With regular replacement or regeneration of used solid zeolite, upgraded biogas can be maintained. This technique proved to be promising in upgrading biogasquality.Keywords: KOH compound, calorific value of biogas, zeolite.
Karakteristik Pembakaran Dan Sifat Fisik Briket Ampas Empulur Sagu Untuk Berbagai Bentuk Dan Prosentase Perekat Fretes, Evedore Fredo de; Wardana, I Nyoman Gede; Sasongko, Mega Nur
Jurnal Rekayasa Mesin Vol 4, No 2 (2013)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

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Abstract

Fossil fuel reserves are depleting to be anticipated by looking for alternative energy sources. Alternative energy that many developed and researched today is agricultural waste biomass fuel is formed into briquettes. In this research, briquettes are made from dregs the pith of sago in the four of form, namely : cylinders, blocks, cubes and prisms, with and without adhesive sago starch with the presentation of 5% and 10%.This research aimed to determine the effect form briquettes on the combustion rate and determine the physical properties of briquettes without carbonization process, with or without the addition of sago starch as an adhesive which include moisture content, ash content, volatile matter, fixed carbon and heating value.The results research that the form of briquettes affects the combustion rate where the fastest combustion speed was on briquettes form beams, cube and Prism. Percentage adhesive of sago starch affects the early combustion time where time is needed to ignite the briquettes greatest for percentage 10% and the lowest adhesive for briquettes without adhesives. Adhesive sago starch is also very influential on the moisture content, ash content, volatile substances, fixed carbon and heating value. Adhesive sago starch is also very influential on the moisture content, ash content, volatile matter, fixed carbon and heating value. The addition of adhesive sago starch lower heating value.Keywords: Briquettes, sago, Physical Properties, Combustion.
Pengaruh Penggunaan Katalis Kalium Hidroksida pada Campuran Minyak Nabati dan Air terhadap Produksi Hidrogen dengan Menggunakan Metode Steam Reforming Mukhtar, Anas; Wardana, I Nyoman Gede; Widodo, Agung Sugeng
Jurnal Rekayasa Mesin Vol 10, No 2 (2019)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2019.010.02.5

Abstract

Steam reforming is a process of hydrogen formation through the process of vaporization of vegetable oil and water at a certain heating temperature using a catalyst, so the chemical reaction is occurred and produced hydrogen gas. The catalysts used is potassium hydroxide (KOH) in the amount of 1 gram, 2 grams, and 3 grams, which are heated at 350oC. To investigate the effectiveness of hydrogen production, the vegetable oil and water mixture is varied of 1:1, 1:2, 1:3. The steam coming out from the pipe is burned to get the color of the flame. The area of flame color is calculated using AutoCAD software, which is the color are a blue flame, yellow flame, and the color of red flame. The calculation results area of the flame colors showed that the greater addition of vegetable oil to water and the greater addition of the potassium hydroxide catalyst is increased hydrogen production.
Reaksi Cairan Jeruk Lemon (C6H8O7) dan NaoH terhadap Tegangan dan Arus yang Dihasilkan dengan Penambahan Katalis Karbon Aktif Amiruddin, Muhammad Agung; Irawan, Yudy Surya; Wardana, I Nyoman Gede
Rekayasa Mesin Vol 11, No 1 (2020)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2020.011.01.13

Abstract

Lemon is an environmentally friendly electrolyte. However, an innovative concept is needed to improve the quality of lemon electrolytes. The purpose of this study is to investigate the effect of activated carbon catalyst addition on the voltage and current electric generated from liquid lemon (C6H8O7) and NaOH. Lemon juice group containing acetone (C3H5O) and 3 carboxylic acid group (COOH). The experimental study was performed using voltaic cells. The data measured is 125 ml of an electrolyte solution of lemon juice (C6H8O7) and NaOH 10 grams. To the solution was added 5 grams, 7.5 grams and 10 grams of activated carbon catalyst. The results showed that the addition of activated carbon can accelerate the breaking molecular bond NaOH and C3H5O (COOH)3 which decomposes into ions react with NaCH2COO + and Cu 2+ cathode into a reductant then OH- from NaOH reacts with the anode Zn2++2e be the oxidant While H2O react exothermically. Produces a voltage between 800-1130 mV second. It occurs when electrons flow from the anode interested Zn2+ + 2e react with H2O and of  Zn2+ + 2e electrons pass led and resistor toward the cathode Cu2+. Cathode Cu 2+ reacts with C6H8O7 and NaOH. The currents that produced ranged from 33.846 to 43.462 mA second. The mechanism of this voltage and current generation makes LED light was on.
Perbandingan Interaksi Karbon Aktif dengan Polaritas Minyak Nabati terhadap Karakteristik Pembakaran Premixed Purnami, Purnami; Wardana, I Nyoman Gede
Jurnal Rekayasa Mesin Vol 12, No 1 (2021)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jrm.2021.012.01.9

Abstract

Crude oil consumption has increased since the discovery of crude oil-fueled engine technology. However, the increase in crude oil consumption is not offset by the productivity of the product. This results in a reduced availability of crude oil. One solution found was to use alternative fuels from vegetable oils. Several researches have proven that vegetable oils can be used as fuel. The results of the research found potential in jatropha oil and palm oil. However, jatropha oil and palm oil contain glycerol compounds which can affect the results of its combustion, because glycerol can absorb heat and result in firing more difficult. Based on that, modification and development are needed to support the use of jatropha oil and palm oil as alternative fuels by studying oil polarity and adding catalysts for coconut shell-activated carbon. Jatropha oil has low polarity (C18) which is more volatile than palm oil which has high polarity (C13). The variation used in this research is the addition of activated carbon with a concentration of 0 ppm, 200 ppm, and 400 ppm in each oil. The addition of activated carbon will facilitate evaporation because oil molecules become more reactive more freely.
GREEN STRUCTURAL LIGHTWEIGHT CONCRETE UTILIZING MEDIUM-K BASALTIC ANDESITIC PUMICE AND SCORIA Agoes Soehardjono; Hendro Suseno; I Nyoman Gede Wardana; Arief Rahmansyah
Journal of Environmental Engineering and Sustainable Technology Vol 4, No 2 (2017)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (552.176 KB) | DOI: 10.21776/ub.jeest.2017.004.02.8

Abstract

ABSTRACTThis study presented observations of the suitability of medium-K basaltic andesitic pumice and scoria as a coarse aggregate on structural lightweight concrete that was environmental friendly and energy saving. Testing results indicated that this typical pumice and scoria fulfilled the requirements as a coarse lightweight aggregate. The mix design of specified compressive strengths yielded a lower proportion of Portland Pozzolan Cement (PPC) than previous studies. Testing results of fresh concrete showed a satisfactory workability at determined slump values without segregation and excessive bleeding. Testing results of hardened concrete showed that the density reduction was about 20 %, but there was a density of scoria lightweight concrete that exceeded slightly the requirements. All compressive strengths complied with the requirement but there was a pumice lightweight concrete that did not reach the specified compressive strength. The modulus of elasticity and splitting tensile strength were relatively low compared to normalweight concrete as control, whereas drying shrinkage was lower than in previous studies.KEYWORDS : green lightweight concrete, pumice, scoria, environmental friendly, energy saving.
Prevalensi Hiperlordosis Lumbalis pada Mahasiswi Jurusan Tari Fakultas Seni Pertunjukan Institut Seni Indonesia Denpasar Bali Angkatan Tahun 2018-2020 Wiraputri, A. A. Wulanatalia; Wardana, I Nyoman Gede; Widianti, I Gusti Ayu; Muliani, Muliani
E-Jurnal Medika Udayana Vol 11 No 5 (2022): E-Jurnal Medika Udayana
Publisher : Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/MU.2022.V11.i05.P17

Abstract

Background: The spinal curvature of an adult varies in normal range. Abnormal curvature of the spine is known as scoliosis, kyphosis, and lordosis. There areseveral factors that can cause spinal abnormalities, one of which is the continuous application of abnormal posture. Body posture during traditional Balinese dance is considered abnormal because it applies positions such as excessive curving of the spine and puffing out the chest towards the front so that the dancer's body curve is seen more clearly. Poor posture that is used continuously can affect the curvature of the spine. Objective: The study was to identify the prevalence of lumbar hyperlordosis in Dance Department Students, Faculty of Performing Arts, Indonesian Arts Institute Denpasar Bali Batch of 2018-2020. Method: This study is a descriptive quantitative study with a cross-sectional design. The research sample was 44 students of the Department of Dance. Allsamples were given a self-data questionnaire then the spinal curvature was measured with a flexicurve. Analysis of the data collected in univariate andbivariate analysis, processed using SPSS Version 26 using cross tabulation. Result: The prevalence of students experiencing lumbar hyperlordosis was found more than normal lumbar lordosis, namely 35 people (79.5%) with hyperlordosis and 9 people (20.5%) with normal lumbar lordosis. Conclusion: The prevalence of lumbar hyperlordosis was higher than normal lumbar lordosis in female students with Balinese dance activities. Keywords : Balinese dancer, lumbar lordosis, flexicurve ruler
PENGARUH LATIHAN LOMPAT TALI SELAMA DUA MINGGU TERHADAP KEKUATAN FUNGSI SISTEM KARDIORESPIRASI DAN KEKUATAN OTOT TUNGKAI BAWAH PADA MAHASISWI JENJANG SARJANA KEDOKTERAN ANGKATAN 2020 UNIVERSITAS UDAYANA Cahyani, A.A. Istri Nanda Pramesthi; Wardana, I Nyoman Gede; Widianti, I Gusti Ayu; Muliani, Muliani
E-Jurnal Medika Udayana Vol 13 No 6 (2024): E-Jurnal Medika Udayana
Publisher : Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/MU.2024.V13.i06.P05

Abstract

Lompat tali lebih dikenal luas sebagai alat permainan tradisional oleh kalangan remaja. Namun, remaja jarang mengetahui bahwa lompat tali dapat dimanfaatkan sebagai olahraga aerobik yang mudah untuk dilakukan. Rutin melakukan latihan lompat tali dapat meningkatkan kebugaran jasmani sehingga menurunkan risiko penyakit kronis dikemudian hari. Penelitian ini bertujuan untuk mengetahui pengaruh latihan lompat tali selama dua minggu terhadap kekuatan fungsi sistem kardiorespirasi dan kekuatan otot tungkai bawah pada mahasiswi kedokteran Universitas Udayana. Rancangan penelitian adalah true experiment dengan metode pre-test dan post-test control group design. Sebanyak 12 mahasiswi dipilih secara purposive sampling kemudian dibagi secara acak menjadi dua kelompok. Kelompok perlakuan melakukan latihan lompat tali sementara kelompok kontrol melakukan jalan santai. Sesi latihan dilakukan selama dua minggu dengan frekuensi latihan tiga kali seminggu. Kekuatan kardiorespirasi diukur dengan menggunakan kadar VO2 maksimal dan denyut nadi sedangkan kekuatan otot tungkai bawah diukur dengan menggunakan selisih lompatan tertinggi. Analisis statistik menggunakan paired t-test dan independent t-test. Uji paired t-test kelompok perlakuan menunjukkan perbedaan signifikan nilai denyut nadi dan VO2 maksimal dengan p < 0.05 dan tidak signifikan pada nilai tinggi lompatan p > 0.05. Namun, uji independent t-test dengan kelompok kontrol tidak menunjukkan hasil signifikan pada nilai denyut nadi, VO2 maksimal, dan tinggi lompatan dengan p > 0.05. Latihan lompat tali selama dua minggu meningkatkan kekuatan fungsi sistem kardiorespirasi tetapi tidak meningkatkan kekuatan otot tungkai bawah pada Mahasiswi Jenjang Sarjana Kedokteran Angkatan 2020 Universitas Udayana. Kata Kunci: Lompat tali, denyut nadi, VO2 maksimal, tinggi lompatan, kardiorespirasi
JENIS KELAMIN, ANGKATAN, DAN DURASI DUDUK BERHUBUNGAN DENGAN ANGKA KEJADIAN NYERI PUNGGUNG BAWAH PADA MAHASISWA PROGRAM STUDI SARJANA KEDOKTERAN DAN PROFESI DOKTER FAKULTAS KEDOKTERAN UNIVERSITAS UDAYANA SELAMA PELAKSANAAN KULIAH DARING Alamsyah, Ajib Zaim; Karmaya, I Nyoman Mangku; Wardana, I Nyoman Gede; Widianti, I Gusti Ayu
E-Jurnal Medika Udayana Vol 12 No 3 (2023): E-Jurnal Medika Udayana
Publisher : Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/MU.2023.V12.i03.P16

Abstract

Nowadays in this pandemic era, most of the living sectors are obligated to adapt and conduct their duty from home. However, home environment isn’t always designed as a place to study, unlike campus, which is risky to be unergonomic. Moreover, this condition can result in various musculoskeletal disorders, such as low back pain. The aim of this study is to find out the prevalence of low back pain in Undergraduate Study Program in Medicine and Medical Profession Students of Udayana University during online classes. The design of this research is description with a cross-sectional approach. The research subjects were 468 Undergraduate Study Programs in Medicine and Medical Profession Students of Udayana University. Research data are primary data obtained from the standardized Nordic questionnaire. Students with low back pain is found in a higher proportion, which is 59% compared to not having low back pain which is 41%. Factors that are related towards this condition are sex with the p value = 0.000, batch with the p value = 0.016, and sitting duration with the p value = 0.002.