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ASEAN Journal on Science and Technology for Development
Published by Universitas Gadjah Mada
ISSN : 22249028     EISSN : 22249028     DOI : -
Core Subject : Science, Education, Engineering,
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Mathematics
The coverage is focused on, but not limited to, the main areas of activity of ASEAN COST, namely: Biotechnology, Non-Conventional Energy Research, Materials Science and Technology, Marine Sciences, Meteorology and Geophysics, Food Science and Technology, Microelectronics and Information Technology, Space Applications, and Science and Technology Policy, Infrastructure and Resources Development.
Arjuna Subject : -
Articles 477 Documents
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A Catalyst Reusability Study in Palm Fatty Acid Distillate and Glycerol Esterification using Multi-Criteria Decision Analysis and Reaction Kinetics Approach Hanifrahmawan Sudibyo; Febbie Setyaningrum; Rochmadi; Mohammad Fahrurrozi
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.612

Abstract

As a byproduct of the physical refinement of crude palm oil, palm fatty acid distillate or PFAD has a potential to be transformed into monoglycerides by means of irreversible esterification with glycerol over a cation exchange resin catalyst. Irreversibility of the esterification can be assured by continuous azeotropic removal of water by adding xylene as an entrainer. Because PFAD-glycerol esterification demands high temperatures for fast conversion and high selectivity of monoglycerides, it is necessary to test catalyst reusability performance. In this research, evaluation of catalyst reusability performance was based on five parameters: free fatty acid conversion, the rate of free fatty acid decomposition, the selectivity of monoglycerides, monoglyceride concentration, and the cation exchange capacity of the catalyst. The cation exchange resin used was Tulsion T-42 SM. The evaluation was conducted using the simple multi-attribute rating technique extended to ranking (SMARTER) method. The results showed that the optimum reaction temperature was 180°C. Ultimately, a kinetic study at 180°C was also performed to model the reaction after using similar catalysts for certain times. This kinetic study revealed that the reaction mechanism changed from Langmuir-Hinshelwood to Eley-Rideal after several cycles of catalyst reuse.  
Dynamic Changes Analysis of Land Resource Balance in North Maluku Province, Indonesia Elya Pratiwi Isti Faroh; Fatih Cinderaswari Puspaningrani; Gema Reinadova; Muhammad Rais Akbar; Novanna Dwi Septyo Anggraeni; Oki Silvie Wildiyanti; Utia Kafafa; Ratih Fitria Putri
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.613

Abstract

Land resources are part of nature related to the availability of water, nutrients, and food that are dynamic and play an important role in the lives of living creatures, including humans. From time to time, land use experiences changes in response to human activities that benefit their lives. This research was conducted to determine trends in land use change in North Maluku Province, Indonesia, as well as to find out the land resource balance and land carrying capacity in the province. The methods comprised a simple descriptive and quantitative analysis along with spatial analysis using GIS. The results showed that land use in North Maluku Province for paddy fields was higher than that for non-paddy land use. However, the increase in non-paddy land use was greater every year compared with the increase in paddy land use. The land resource balance in North Maluku Province in 2010–2018 also showed a decrease in non-agricultural protected forest, by 150,895.79 ha, as well as an increase in 4,286 ha of irrigated paddy fields. Meanwhile, the land carrying capacity during this same period was found to be declining at a rate of 6% per year, based on the population increase each year within a permanent land area.
Optimization of Building Configuration in Vertical Residential Housing towards Outdoor Thermal Comfort: Case Study of Tambora Flats, Jakarta, Indonesia Khairani Ayu Rizqi; Budi Prayitno
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.614

Abstract

Population growth in Indonesia is not offset by the construction of urban facilities and infrastructure and the improvement of urban services. In densely populated urban areas with narrow residential conditions, the demand for shelter is higher, causing an increase in the price of land and housing. One of the efforts in responding to this problem in the Special Capital Region of Jakarta is to build vertical residential or flats. This study aimed to determine the level of outdoor thermal comfort of Tambora flats in Jakarta, which have air temperatures ranging 26–29°C and air humidity of 76–92%. Existing flats were simulated with the Envi-MET 3.1 software, with the first stage being to determine the height of the building and material of the building, the street, and then assessing the existing outdoor thermal comfort level by inputting climatic data. Overall, the thermal comfort index values of both existing and planned model building configurations of Tambora flats and its surrounding area were at the standard level for a humid climate. Of our models, model B had the best potential to provide thermal comfort to humans in the area of the flats. In order to implement the proposed model building configuration with optimal outdoor thermal comfort in real buildings, future research should focus on a wider range of aspects, including diversity and density of buildings, and neighborhood type.
Global Retrofitting Strategies for an Existing Three-storied RC School Building in Mandalay, Myanmar Thiri Thwe; Nang Su Le′ Mya Thwin; Ne Min Hein
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.616

Abstract

Low to severe earthquakes occur around the world every year, damaging and causing structural failure in buildings. Consequently, seismic improvements are required for existing buildings that are vulnerable to damage by seismic forces. The objective of this study was to investigate retrofitting strategies in terms of their sustainability. Mandalay, Myanmar, was selected as the study area as it is located near the Sagaing fault, which itself is in a strong earthquake zone (seismic zone 4). A three-storied RC building with a non-seismic design was selected as a case study building. An investigation was carried out into the performance and vulnerability of the building under three earthquake hazard levels. The vulnerability index value was calculated using the Priority Index method. Meanwhile, non-linear static pushover analysis was performed to investigate the performance of the existing building using SAP2000 V14 software. Four different types of retrofitting strategies were considered, namely reinforced concrete shear walls with openings, reinforced concrete shear walls without openings, steel plate shear walls, and finally steel bracing. Among these, it was found that the use of steel plate shear walls was the best retrofitting technique, owing to it having the best performance along with the lowest displacement. Its performance level reached up to the Immediate Occupancy (IO) level even under the conditions of a Maximum Consider Earthquake (MCE).
Two Approaches to Measure Trace Metals Fluxes at the Sediment–Water Interface: Sediment Porewater Profile and Benthic Incubation Harmesa; A’an Johan Wahyudi
ASEAN Journal on Science and Technology for Development Vol. 37 No. 3 (2020): Movement
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.617

Abstract

The biogeochemical cycle of trace metals is very likely affected by the global change in the ocean, especially due to the increasing of sea surface temperature and acidity. Thus, assessing biogeochemical cycle of trace metals will beneficial in elucidating the potential impact of climate change as well as ocean acidification. The assessment of the biogeochemical cycle of trace metals can be performed by measuring trace metals fluxes crossing the sediment–water interface. The main challenge in this measurement is the difficulty of measuring metal concentrations at trace levels due to either physical factors or biological factors that can affect the total flux. Sediment porewater profile and in situ benthic incubation are the two most commonly used methods for measuring trace metals fluxes from sediment to the overlying water or vice versa. The coefficient of diffusion and gradient of concentration are the two most important values in the sediment porewater profile method, while the constant volume involved in the container during the experiment is an important part of the in situ benthic incubation method. The purpose of this review is to provide an overview of both measurement methods deeply and predict the challenges faced in its implementation in Indonesia.
Spatio-temporal Variations in Bacterial Abundance with an Emphasis on Fecal Indicator Bacteria and Vibrio spp. in and around Visakhapatnam Port, East Coast of India Lidita Khandeparker; Dattesh V. Desai; Subhash Shivram Sawant; Venkat Krishnamurthy; Arga Chandrashekar Anil
ASEAN Journal on Science and Technology for Development Vol. 37 No. 3 (2020): Movement
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.619

Abstract

The ecological health of port environments, which are dynamic and hotspots of anthropogenic activities, can be analyzed using specific pathogenic bacteria as they provide definite evidence and source of pollution. The influence of seasons and environmental settings on total bacterial count (TBC), distribution of fecal indicators, and Vibrio spp. was explored in Visakhapatnam port, located along the east coast of India. South-west monsoon had a significant influence on TBC, fecal indicators, and Vibrio spp., and the abundance was influenced by the eutrophic environment in the inner harbour. Fecal indicators were one order higher in sub-surface water when compared with sediment, indicating their inoculation due to turbulent conditions in south-west monsoon. The abundance of V. cholerae was influenced by salinity, temperature, and SPM, and was positively correlated to plankton; relating their distribution with disease dynamics and ecosystem functioning is a step ahead. Such an assessment is important from the perspective of human health and marine bioinvasion.
Application of Biogasoline in a Four-stroke Motorcycle Engine Sutrisna Saputra; Karna Wijaya; Mudjijana
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.621

Abstract

The problems facing the world, in relation to the increasing consumption of petroleum and its limited sources, as well as pollution by fuel-related gases, such as CO, have sparked research on the application of biogasoline as an environmentally friendly alternative fuel. Our research aimed to determine engine performance through mixtures of biogasoline and gasoline to measure torque, power, and fuel consumption rate, and to determine the effect of the mixture on the level of air pollution. The biogasoline used was previously prepared from cooking oil through a Cr-zeolite-catalyzed process. The testing methods on the fuel mixture as a working substance included engine performance and exhaust emission tests, applied to four-stroke engines with mixtures with gasoline and biogasoline ratios of 95:5, 90:10, and 85:15. The engine performance test results showed that the highest values of torque, power, and average effective pressure were of the fuel with a composition of 85:15. CO and HC, the two emitted gases with high toxicities, based on the air quality standard, should not be more than 5.5% by volume and 2400 ppm, respectively. In this research, the findings indicated that both substances, not exceeding 3.0% by volume and not more than 200 ppm, respectively, are safe and environmentally friendly.
Comprehensive Assessment on the Environmental Conditions of Abandoned and Inactive Mines in the Philippines Jessie Samaniego; Cris Reven Gibaga; Alexandria Tanciongco; Rasty Rastrullo; Norman Mendoza; Charles Darwin Racadio
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.623

Abstract

Most abandoned and inactive mines in the Philippines pose high risks to human health and the environment due to the disturbed and exposed heavy metal-laden soils and sediments and water-filled open pit mines. Establishing these mines’ environmental conditions remains a challenge as it requires time, effort, resources, and faces a lack of funding as the economic phase of the mine has already ceased. In order to contribute to the solution on the assessment of abandoned and inactive mines, integrated methods with combined essential testing, sampling, and analyses of different environmental media present in the mine site are suggested in this paper. On-site and laboratory methods include analyses for water (surface water and groundwater characterization, quality assessment, and environmental isotope tracers), soils and sediments (heavy and trace metals, anomalous elements, erosion, and nutrient availability), air quality, and radiometric survey. These methods can be classified as rapid with complete data, and information can be gathered to support a health risk assessment in the area, as well as used as a guide for rehabilitation prioritization of the abandoned mines.
Water Quality Assessment and Monitoring of Closed Rearing System of the Sea Cucumber Holothuria scabra Hanny Meirinawati; Hanif Budi Prayitno; Lisa Fajar Indriana; Muhammad Firdaus; A'an Johan Wahyudi
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.624

Abstract

Sea cucumbers are an essential fishery resource. Therefore, effective aquaculture methods should be developed to achieve their optimal production. Sea cucumbers are susceptible to various environmental factors, one of which is water quality. Monitoring water quality based on physical and chemical parameters should be useful to the rearing system in aquaculture. In practical use, farmers usually monitor only temperature, salinity, and pH, neglecting the essential role of chemical parameters. This review focuses on and urges the monitoring of physical and chemical parameters. We explored the water quality parameters that may be crucial to the sea cucumber rearing system, including temperature, salinity, pH, dissolved oxygen, ammonia, turbidity, particulate organic matter, total nitrogen, nitrate, nitrite, ammonium, silicate, and phosphate. Furthermore, this paper presents a practical way to monitor the aquaculture or rearing system of sea cucumbers. It is suggested that temperature and salinity are the crucial physical parameters, while the essential chemical parameters are phosphate, nitrate, and ammonia.
Reply to Letter to the Editor: The Invasive Caribbean Mytilopsis sallei (Bivalvia: Dreissenidae): A Short Review Koh Siang Tan; Teresa Tay
ASEAN Journal on Science and Technology for Development Vol. 37 No. 2 (2020): The Perennial Quest
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.625

Abstract

This letter provides a response to the letter concerning "The Invasive Caribbean Mytilopsis sallei (Bivalvia: Dreissenidae): a Short Review" by Tan and Tay in AJSTD 35(1–2): 133–139.

Page 43 of 48 | Total Record : 477

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