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Eddy Currents Variablity from Satellite Altimetry and Its Relation to Physical Conditions of Java Sea
Full text linkCurrent pattern in Java Sea highly depends on monsoonal cycles, which create alternating conditions according to the seasons throughout the year and potential impacts on eddy currents variability. Using the surface geostrophic current data from satellite altimetry during 2013-2017, this study aims to understand the variability of eddy currents and its relations to the physical condition of the Java Sea such as sea surface temperature (SST), sea surface height (SSH), and chlorophyll-a concentration (CHL). Results showed 60 occurrence of eddy currents in the study area, 40 cyclonic and 20 anticyclonic. The largest cyclonic eddy observed in April 2013 (112.05, -5.37) with a diameter of 134.07 km, while the largest anticyclonic eddy observed in October 2017 (114.54, -6.24) with a diameter of 159.69 km. Cyclonic eddy has lower SSH and cold core while anticyclonic eddy has higher SSH and warm core. Despite having an unclear pattern during the five years period, the occurence of Eddy current has a potentially indirect influence on Chl-a concentration
REDUCE CO ON CAR BY USING ZEOLITE
Full text linkThe number of vehicles in Jakarta increased by 5.66% from 2016. Vehicles have the highest contribution to air pollution, which is 70% of other activities. The purpose of this study was to determine the reduction of CO with zeolite pellets. This type of research is a quasi-experimental design with a non-equivalent control group design pre-test post-test design. The emission test instrument uses the automotive gas analyzer HESBOHN, a tachometer to measure engine speed, laptops, and stopwatches. The material used is activated natural zeolite pellets. Data were analyzed by univariate in the form of CO adsorption power efficiency, average, minimum, and maximum. The variables used are pellet drying time (3 hours and 24 hours) and engine speed (idle and 1250 rpm). The result of CO adsorption power efficiency using the most optimal zeolite pellets is Pellet I with 3 hours drying at 1250 rpm by 52%. While the lowest yield is Pellet II with 24-hour drying at idle conditions of 22%. The most effective CO emission reduction is by using Pellet I at 1250 rpm
CO-PYROLYSIS CANGKANG KELAPA SAWIT DAN LIMBAH PLASTIK KEMASAN
Full text linkIn the present study, the co-pyrolysis of biomass waste, i.e. palm kernel shells (PKS) and industrial packaging plastic waste, namely polyethylene terephthalate (PET) and polyethylene (PE) were conducted. Prior to the pyrolysis, the raw materials were analyzed by thermogravimetric and elemental procedures. The pyrolysis was conducted in a fixed bed reactor which was heated from room temperature to 500 °C in an N2 atmosphere with a heating rate of 10 °C/min. The raw materials were weighted and mixed together manually with variations of weight composition ratios between biomass and plastic, i.e. 100% biomass (100/0); 90% biomass and 10% plastic (90/10); 70% biomass and 30% plastic (70/30); 50% biomass and 50% plastic (50/50); and 100% plastic (0/100). Then, they were put under pressure to obtain a pellet. The synergistic effect of biomass and plastic was investigated to see the difference between the pyrolysis products yields in theory and experiment. The bio-oil products were characterized by several methods and showed the potential to be used as a fuel. The optimum condition was obtained from 50/50 weight composition ratio. It was gained 30% improvement of the higher heating value of bio-oil, and the percentage area of hydrocarbon was contained in bio-oil increased from 4.68% to 53.40%
PENGARUH JUMLAH SALURAN MASUK UDARA TERHADAP DISTRIBUSI KECEPATAN UDARA PENGERING PADA ALAT PENGERING TIPE SWIRLING FLUIDIZED BED
Full text linkNumerical and experimental studies have been carried out on the effect of inlet air number to the air velocity distribution in the drying chamber of the Swirling Fluidized Bed Dryer (SFBD). The main components of SFBD are a drying chamber, plenum chamber, center body, distributor, inlet air, heater, and blower. Numerical analysis was performed using the finite volume method on a three-dimensional model using computational fluid dynamic (CFD) software. An experimental study was carried out by measuring the air velocity at eight measurement points in the drying chamber. The results showed that using two inlet air produced a more uniform distribution of air velocity compared to one inlet air
PENGARUH KOMPOSISI LELEHAN DAN WAKTU CELUP TERHADAP STRUKTUR MIKRO LAPISAN HOT DIP ALUMINIZING PADA BAJA TAHAN KARAT MARTENSITIK
Full text linkPada material aplikasi suhu tinggi, pelapisan permukaan merupakan hal penting dalam memberikan ketahanan oksidasi dan korosi suhu tinggi, ketahanan erosi dan abrasi. Pelapisan alumunium pada baja tahan karat martensitik AISI 410 melalui metode celup panas (hot dip) cukup efektif untuk memberikan perlindungan pada substrate melalui senyawa-senyawa intermetalik yang terbentuk. Proses hot dip aluminizing dilakukan dengan preparasi penghalusan permukaan sampel menggunakan amplas grit 100, 400, 800, dan 1200. Kemudian sampel dibersihkan menggunakan larutan 15% H2SO4 sebelum dilakukan proses celup panas. Spesimen tersebut dikaitkan menggunakan kawat nikel untuk memudahkan proses pencelupan. Komposisi lelehan Al-Si, waktu pencelupan, dan waktu difusi memberikan pengaruh terhadap lapisan intermetalik yang terbentuk beserta sifat mekanisnya. Telah dilakukan karakterisasi morfologi lapisan hot dip aluminizing pada spesimen baja tahan karat martensitik yang dilapisi oleh Al Murni, 5 %wt Si, 10 %wt Si, dan 15 %wt Si dengan variasi waktu pencelupan 1 menit, 3 menit, dan 5 menit dengan menggunakan SEM – EDS. Pada komposisi lelehan dengan komposisi 5%wt Si dengan perlakuan permukaan yang sama oleh larutan H2SO4 memberikan hasil lapisan intermetalik yang lebih baik. Dapat dilihat dari kehalusan struktur mikro dan ketebalan lapisan yang dihasilkan berdasarkan variasi waktu pencelupan. Unsur Si memberikan pengaruh dalam merubah morfologi struktur antarmuka antara intermetalik dengan substrate
PENGARUH PENAMBAHAN KONSENTRASI INHIBITOR EKSTRAK DAUN TALAS TERHADAP LAJU KOROSI PADA BAJA API 5L X-52 DENGAN MEDIA KOROSIF H2SO4 0,5 M
No full textInhibitor merupakan salah satu alternatif untuk mengendalikan laju korosi.Pada umumnya bahan yang digunakan sebagai inhibitor adalah bahan kimia yang tidak ramah lingkungan.Oleh karena itu, berbagai penelitian dilakukan untuk mendapatkan inhibitor dari bahan alam yang mengandung antioksidan tinggi.Salah satu tumbuhan tersebut adalah daun talas. Dalam penelitian ini digunakan baja karbon API 5L X-52, dengan media korosif H2SO4 0,5 M dan variasi konsentrasi dari ekstrak daun talas 0 ppm, 500 ppm, 1000 ppm, 5000 ppm, dan 10000 ppm. Daun talas diekstrak dengan menggunakan metode maserasi. Efektivitas penggunaan inhibitor organik daun talas dalam asam akan diketahui melalui Uji Imersi (Weight Loss). Hasil penelitian menunjukkan bahwa efisiensi inhibisi meningkat dengan peningkatan konsentrasi inhibitor, yang berarti semakin menurunnya laju korosi. Efisiensi inhibisi optimum diperoleh pada konsentrasi inhibitor 10000 ppm yaitu 79,53% dengan laju korosi 1,62218 mm/tahun
EVALUASI HASIL PEMODELAN BATIMETRI DARI BEBERAPA KOMBINASI SATELIT ALTIMETRI PADA LAUT NATUNA DAN LAUT SULAWESI
No full textIndonesia is an archipelago country where 77% of its territory is waters. National marine mapping has been carried out based on depth measurement data obtained using echosounders. However, this method requires a lot of time and cost. One solution to provide Indonesian bathymetry data is by utilizing altimetry satellite data to model the bathymetry of the seafloor. This study aims to evaluate bathymetric model generated from three combinations of five altimetry satellites in shallow and deep seas. We use least square collocation gravity anomaly and geological gravity for bathymetry modeling. The results of the model show variations in deviations with sounding data available at the Geospatial Information Agency (BIG). The resulting residual trend differs between shallow and deep sea. The optimum results in shallow area is obtained by the combination of Cryosat-2, Jason-1/C, and SARAL while in deep area is obtained by the combination of ERS-1/E-F and Geosat GM. In general, the bathymetry model produced in this study has a similar profile with the sounding data
FAKTOR PENGUNGKIT DAN STRATEGI PENINGKATAN PENGELOLAAN LINGKUNGAN OLEH PERKEBUNAN DAN PABRIK KELAPA SAWIT DI KABUPATEN BATANG HARI
Full text linkEnvironmental management by the oil palm plantation industry has become a necessity in minimizing negative impacts on the environment that have emerged from the construction to the operation stage. The government has made a preventive effort by requiring every industry performer to manage the environment by following the ownership of the company's environmental documents. However, in reality, there are still companies that have not implemented this effort, including in Batang Hari Regency as the regency with the highest number of oil palm companies in Jambi Province. This study aims to identify the lever factors and environmental management strategies by oil palm industry players in Batang Hari District. Data collection was carried out through in-depth interviews with the government, companies and village communities in the study areas, document review, observation, and focus discussion group (FGD) to the district, sub-district and village government research sites. The determination of priority levers is done by determining the important levers first with an average criterion of ≥75%, followed by fit/gap analysis by mapping important factors in quadrant I, and strategies to improve environmental management efforts are carried out using a prospective promethee analysis. The results showed that there were three priority lever factors and six factors that were advantages to improve environmental management. The strategy through the Walfare Pluralism (WP) approach is the best approach with the support of the contribution of the nine factors. This approach emphasizes the role of government, companies and communities through the principle of a five-sector approach (public sector, private sector, voluntary sector, mutual aid, and informal sector) in improving environmental management
DETEKSI TEPI UNTUK VALIDASI MODEL TIGA DIMENSI TULANG PANGGUL PADA PERENCANAAN DESAIN IMPLAN
Full text linkIn the process of implant design and fabrication planning, the anatomical background of human bone is an important aspect to determine the accuracy of implant design. To help in understanding the human bone anatomy, replicas of human bone can be reconstructed using three-dimensional (3D) printing technology. This study aims to validate the digital model of human bone and the imaging data of human bone in order to have an appropriate recommendation for designing the total hip replacement (THR). Achieved data from computed tomography scanning (CT-Scan) modality was deciphered to build the digital 3D model human bone. The bone and the digital 3D model of bone were captured to be two-dimensional(2D) data in the same dimension and processed using the algorithm of edge detection. The images from the edge detection process were processed for finding the similarity of the images. The percentage of similarity, precision, and accuracy between the bone and the digital 3D model have been validated and can be used as a reference in the THR designs
IDENTIFIKASI PERUBAHAN POLA CURAH HUJAN DAN PERIODE MASA TANAM DI LAHAN KERING UNTUK ADAPTASI PERUBAHAN IKLIM (STUDI KASUS KABUPATEN BONE, SULAWESI SELATAN)
Full text linkIdentification of climate change impacts on spatial and temporal rainfall pattern and length of growing period are very important for climate change adaptation strategy. Rainfed is an agro-ecosystem most sensitive to changes in rainfall patterns. Bone Regency is a center of agriculture in South Sulawesi and has considerable rainfed potentials. This study aims to identify changes of rainfall patterns and length of growing period (LGP) for paddy and upland rice in Bone Regency. Data of three rain stations with a 55-year period were used and Oldeman methods was applied to determine rainfall pattern and LGP. Data was separated in two period, period 1 (1961-1990) and period II (1991-2016). The pattern of changes were identified by comparing rainfall patterns in LGP I and II. This analysis was grouped by wet year, normal year and dry year with criteria developed by BMKG. The results of the analysis showed that the rainfall pattern and LGP had changed of which pattern of change varies between regions. The LGP of paddy in Macope were three months shorter in all years, while for upland rice were two months shorter in wet year, and 1 month in normal year. In Katumpi, the LGP of paddy fields were 2 months shorter comparing to the wet year and 1 month shorter in normal and dry year for upland rice. LGP for paddy in Cellu was lengthened 1 month in wet year and shortened 2 months in dry year for upland rice