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INDONESIA
Indonesian Journal of Science and Technology
Published by Universitas Pendidikan Indonesia
ISSN : 25278045     EISSN : 25281410     DOI : -
Core Subject : Science, Social,
Computer Science & IT Environmental Science
Arjuna Subject : -
Articles 220 Documents
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Urban Heat Island Assessment using Remote Sensing Data in West Java, Indonesia: From Literature Review to Experiments and Analyses N. Nandi; M. Dede
Indonesian Journal of Science and Technology Vol 7, No 1 (2022): IJOST: VOLUME 7, ISSUE 1, April 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i1.44146

Abstract

Urban heat island (UHI) is a significantly increasing temperature that occurs in the urban region due to urbanization and anthropogenic activities. The UHI represents environmental quality decrease and able to change a microclimate in the long term. It phenomenon can be estimated using multi-temporal remote sensing imagery data. This study aims to analyze the spatial dynamics of UHI in the urban region of West Java from 1998 to 2018. We only used remote sensing data from different datasets. Information of land-surface temperature is extracted from Landsat-5 TM and Landsat-8 OLI images using radiative transfer equation which validated using MODIS data in the same period. This study showed that UHI intensity in the urban region of West Java reach 5.11oC in 2018. For 20 years, the land-surface temperature increased to 4.44oC. The UHI distribution is concentrated in the central business district, industrial area, harbor, terminal, airport, and traffic jam zone. The UHI significantly increased in Depok and Cimahi, which are known as satellite cities for the surrounding megapolitan (Jakarta and Bandung Raya). This model has high validity result with a correlation value of 0.74. The UHI management is important to strengthen urban resilience in the environmental field through green open space, green belts, roof gardens, land use and land cover formal direction, and the use of high albedo materials to build construction.
Risk-Based Leak Analysis of an LPG Storage Tank: A Case Study Suroto Munahar; Bagiyo Condro Purnomo; Nanda Ferdiansyah; Eko Muh Widodo; Moehamad Aman; Retno Rusdjijati; Muji Setiyo
Indonesian Journal of Science and Technology Vol 7, No 1 (2022): IJOST: VOLUME 7, ISSUE 1, April 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i1.42916

Abstract

Liquified petroleum gas (LPG) storage tanks are essential components for storing and distributing fuels. However, system failures due to inspection flaws increase the risk of leaks, fires, and explosions. Therefore, this study discussed the development of a safety system application applied to LPG storage tanks based on a risk-based leak (RBL) analysis. Data associated with risk factor values were obtained from an LPG storage tank in a gas distributor company. The risk of failure was calculated by analyzing the probability of failure (PoF) and the consequence of failure (CoF). The results showed that the level of risk observed was medium-high with a PoF in category 1 at a total damage factor value of 1. Furthermore, the CoF in category E was positioned with a consequence analysis value of 2381.29 m2 with an LPG storage tank life span of 33.5 years and an external inspection interval of five years.
Aerodynamic Performance of Vertical and Horizontal Axis Wind Turbines: A Comparison Review Hesam Eftekhari; Abdulkareem Sh. Mahdi Al-Obaidi; Shahrooz Eftekhari
Indonesian Journal of Science and Technology Vol 7, No 1 (2022): IJOST: VOLUME 7, ISSUE 1, April 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i1.43161

Abstract

The need for energy and electricity has been increasing globally, and this means more power is required from the power plants. Power plants, however, will then continue harming the earth because of the greenhouse gasses produced while generating energies that contribute to global warming. Using renewable sources to produce clean energies is one of the sustainable methods to deal with such challenges. Wind energy is one of the renewable sources, which is accessible anywhere on earth, creating green energy. Wind turbines are mainly categorized into Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT). This paper firstly presents a general comparison between the HAWTs and VAWTs. Then, it presents mathematical modelling for the aerodynamic factors of HAWT and Darrieus VAWT to assist the researchers to understand some key design aspects of wind turbines, such as lift/drag ratio, tip speed ratio, power coefficient, and torque coefficient. Also, this paper presents a review of the aerodynamic performance of the recent VAWT designs to help researchers to identify and choose the best model among the Savonius and Darrieus rotors for further development or designing a new model at different wind conditions. This comparison review shows that for a large scale HAWT upwind 3 bladed wind turbines are the most optimum. The helical Savonius rotors perform better by having positive torque coefficient at all azimuth angles. Moreover, helical Darrieus was found to produce lesser noise and suitable for conventional areas. hybrid Savonius-Darrieus rotors can solve the self-starting challenge of the VAWTs, and they are suitable at low wind speeds. At last, this review shows some of the recent hybrid Savonius-Darrieus rotors which would help to solve the low efficiency of Savonius rotor and self-starting challenge of Darrieus rotors.
Crosslinked Spin-Assisted Layer-by-Layer Polyelectrolyte Nanofiltration Membrane: From Literature Review to Experiment Farid Fadhillah
Indonesian Journal of Science and Technology Vol 7, No 1 (2022): IJOST: VOLUME 7, ISSUE 1, April 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i1.45181

Abstract

Layer-by-Layer (LbL) assembly is considered as the most versatile and robust method in thin-film fabrication. However, its use in the preparation of desalination membrane is still in its infancy. Spin-assisted layer-by-layer assembly (SA-LbL), one of the LbL variants, was selected for the fabrication of a nanofiltration membrane due to its versatility to produce an ultra-thin film with highly controlled film properties within an incredibly short time. Branched-polyethyleneimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS) were employed and alternately deposited on the top of the ultrafiltration polyethersulfone (PES) substrate. PEI/PSS film was then crosslinked using Gluteraldehyd (GA). The resulting membrane was tested at a feed concentration of 2000 ppm NaCl, a pressure of 10 bar, and a temperature of 25°C. Crosslinking time and many layers were varied to investigate the extent of crosslinking and its impact on membrane performance. The permeation test of (PEI/PSS)10 crosslinked for 6 hours showed rejection of 94.2 % and water flux of 4.2 L/h·m2 meanwhile uncrosslinked (PEI/PSS)35 showed rejection of 75.66% only. The result showed that crosslinking improved the rejection of NaCl with a smaller number of layers. This result also displayed SA-LbL method is promising and can be used to produce membrane suitable for NF or RO application.
A review of recent advances in metaheuristic maximum power point tracking algorithms for solar photovoltaic systems under the partial-shading conditions T. Sutikno; A. Pamungkas; G. Pau; A. Yudhana; M. Facta
Indonesian Journal of Science and Technology Vol 7, No 1 (2022): IJOST: VOLUME 7, ISSUE 1, April 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i1.45612

Abstract

Several maximum power point (MPP) tracking algorithms for solar power or photovoltaic (PV) systems concerning partial-shading conditions have been studied and reviewed using conventional or advanced methods. The standard MPPT algorithms for partial-shading conditions are: (i) conventional; (ii) mathematics-based; (iii) artificial intelligence; (iv) metaheuristic. The main problems of the conventional methods are poor power harvesting and low efficiency due to many local maximum appearances and difficulty in determining the global maximum tracking. This paper presents MPPT algorithms for partial-shading conditions, mainly metaheuristics algorithms. Firstly, the four classification algorithms will be reviewed. Secondly, an in-depth review of the metaheuristic algorithms is presented. Remarkably, 40 metaheuristic algorithms are classified into four classes for a more detailed discussion; physics-based, biology-based, sociology-based, and human behavior-based are presented and evaluated comprehensively. Furthermore, the performance comparison of the 40 metaheuristic algorithms in terms of complexity level, converter type, sensor requirement, steady-state oscillation, tracking capability, cost, and grid connection are synthesized. Generally, readers can choose the most appropriate algorithms according to application necessities and system conditions. This study can be considered a valuable reference for in-depth works on current related issues.
Active Disturbance Rejection Control of Wearable Lower-Limb System Based on Reduced ESO Nasir Ahmed Alawad; Amjad J. Humaidi; Abdulkareem Sh. Mahdi Al-Obaidi; Ahmed Sabah Alaraji
Indonesian Journal of Science and Technology Vol 7, No 2 (2022): IJOST: VOLUME 7, ISSUE 2, September 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i2.46435

Abstract

Wearable robots are commonly used for rehabilitation and they are made to fit the human body to assist persons who are unable to help themselves. The design of controllers became necessary to enhance the dynamic motion of these exoskeleton systems when worn by patients. In this study, active disturbance rejection control (ADRC) with reduced-order extended state observer (RESO) has been proposed for motion control of exoskeleton knee-assisting device to eliminate the phase lag induced by full-order extended state observer (FESO). The design analysis of RESO-based ADRC has been presented and a computer simulation has been conducted to verify the effectiveness of the proposed controller. A comparison study has been made between ADRC based on RESO and that based on FESO in terms of transient and robustness characteristics. The simulated results showed that the RESO-based ADRC gives better transient and load rejection capabilities compared to the controller with FESO.
Anti-Cancer Effect of Phosphatidylcholine Containing Conjugated Linoleic Acid at sn-2 Position on MCF-7 Breast Cancer Cell Line Riska Rian Fauziah; Chin Rie; Tomoyuki Yoshino; Shinjiro Ogita; Yukihiro Yamamoto
Indonesian Journal of Science and Technology Vol 7, No 2 (2022): IJOST: VOLUME 7, ISSUE 2, September 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i2.50663

Abstract

Conjugated linoleic acid (CLA) exhibits anti-cancer effects; however, most studies have only investigated its free fatty acid forms (CLA-FFA). Here, we compared the anticancer effect of CLA with its lipid forms (FFA and phosphatidylcholine [PC]) on the breast cancer cell line MCF-7 with Soy-PC as a control. CLA-FFA, CLA-PC, and Soy-PC caused a dose- and time-dependent inhibition of MCF-7 growth. However, the lowest antiproliferative activity was observed with CLA-PC. These results were consistent with Hoechst staining and protein expression of apoptosis markers Bax and Bcl-2. Interestingly, CLA-PC uptake was four times lower than that of Soy-PC, which may have affected its antiproliferative effect. Many papers showing that phospholipid forms of functional compounds have superior activity than intact forms have been reported, however, our results suggest that the PC form of CLA was inferior to its FFA form in inhibiting MCF-7 cell growth. This is the first report showing that the phospholipid form is not always the superior form.
Analysis of the behavior of asynchronous electric drive with a closed scalar control system when changing the inductance of the magnetizing circuit Yu. L. Zhukovskiy; B. Y. Vasilev; N. A. Korolev; Y. M. Malkova
Indonesian Journal of Science and Technology Vol 8, No 1 (2023): IJOST: April 2023
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v8i1.51983

Abstract

The article was devoted to the study of an automated electric drive with a scalar closed-loop speed control system. Severe duty and operating modes of electric drive determine the actual service life. Wear of the induction motor, as a key link of the electric drive, was associated with deviation from nominal parameters. The deviation of parameters of the induction motor equivalent circuit determined the resultant change of characteristics. The parameters of the equivalent circuit determined the accuracy of the adjustment of regulators and optimal algorithms in the control system of the electric drive. In continuous operation modes the possibility of auto-tuning regulators, which requires stopping or no-load mode, was excluded. The paper considered the influence of the magnetization circuit mutual inductance value of the induction motor on the behavior of the electric drive control system. Evaluation of the behavior of the scalar closed-loop speed control system was performed on the basic energy (power factor, efficiency factor) and mechanical (speed, electromagnetic torque) characteristics of the electric drive.
Amorphous Iron Phosphate: Inorganic Sol-Gel Synthesis-Sodium and Potassium Insertion Fatima-Ezzahra Maarouf; Sanaa Saoiabi; Khalil Azzaoui; Hind Khalil; Mariam Khalil; Ahmed El Yahyaoui; Ahmed Saoiabi; Belkheir Hammouti; Moulay Hfid Youssoufi; Sergey Shityakov; Othman Hamed; Shehdeh Jodeh; Rachid Sabbahi
Indonesian Journal of Science and Technology Vol 7, No 2 (2022): IJOST: VOLUME 7, ISSUE 2, September 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i2.45948

Abstract

Amorphous iron phosphate, FePO4.2H2O, was synthesized at ambient temperature using an inorganic sol-gel method coupled with a microwave route. The experimental conditions for the gelling of the Fe (III)-H3PO4 system are defined.  Potentiometric Time Titration (PTT) and Potentiometric Mass Titration (PMT) methods were used to investigate the acid-base surface chemistry of obtained phosphate. Variations of surface charge with the contact time, Q = f(t), are examined for time contact ranged from 0 to 72 hours. The concentrations suspensions used for this purpose were 0.75, 1.25, and 2.5 g/L. The point of zero charges (PZC) and isoelectric point (IEP) were defined using the derivative method examining the variations , at lower contact time. A value of 5.4 was obtained for both PZC and IEP. Q in the function of the t method is performed for synthesized FePO4. 2H2O in NaCl and KCl electrolytes. The optimal surface charge of 40 C corresponding to insertion of 4.2x10-4 M of Na+ or K+, is achieved in explored conditions. The results suggest that the synthesized iron phosphate is amorphous.
A Systematic Review of the IoT in Smart University: Model and Contribution Senny Luckyardi; Ratih Hurriyati; D. Disman; Puspo Dewi Dirgantari
Indonesian Journal of Science and Technology Vol 7, No 3 (2022): IJOST: VOLUME 7, ISSUE 3, December 2022
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v7i3.51476

Abstract

The objectives of the review were to identify different implementation aspects of the Internet of Things (IoT) in Smart Universities (SU) from diverse studies, amplify the theories behind the IoT utilization and model in SU; as well as offer recommendations for future research in this area. This study employed a systematic literature review (SLR) technique, conducting comprehensive searches of the most relevant articles to the research question published from 2018 to 2022. Following a review of peer-reviewed journals, a total of 69 refereed articles were chosen and analyzed. The findings of this study suggest that the technology model needs to be aligned and integrated with organizational processes. IoT utilization should meet the adoption readiness of a university. The results also revealed that the creation of SU can be divided into three categories: behavior, learning, educational technology, and physical facilities. However, the literature related to IoT utilization and model is still incoherent and lacking in theoretical frameworks that reflect on specific circumstances such as SU. SU research is still in its early stages, with more work to be done in terms of identifying technology model adoption. The review also contributed to serving as inspiration and a point of reference for institutions as they work with the smart university initiative to create a teaching and learning environment that is more effective and efficient.

Page 17 of 22 | Total Record : 220

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