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The effect of fiber volume fraction on tensile and impact properties of eleusine indica grass reinforced polypropylene bio composite

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IOP Conference Series: Materials science and engineering 2019年第1期539卷

作者： I P Lokantara N P G Suardana I W Surata I N S Winaya Doctoral Study Program of Engineering Science Faculty of Engineering Udayana University Kampus Sudirman Denpasar-Bali Indonesia Mechanical Engineering Department of Udayana University Street of Bukit Jimbaran Badung Bali Indonesia

The purpose of this research was to investigate the tensile strength and impact strength of eleusine indica grass fiber-reinforced polypropylene recycle composite. In this study, the fiber was treated with alkali at 5% NaOH for 2 hours. The eleusine indica grass fiber cut with a length of 3 cm and the matrix used recycle polypropylene. In this research, the volume fraction of eleusine indica grass fiber varied by 20%, 25%, and 30% respectively. The composite molded with a hot press at temperature 200°C with a holding time for 2 hours. Tensile test used ASTM D3039 and impact test used ASTM D256. The highest tensile and impact strength results on fiber volume fraction 30%.

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The investigation of influence ammonia concentration variations to the performance of a pump less ammonia-water absorption refrigeration system with water flooding evaporator

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AIP Conference Proceedings 2019年第1期2062卷

作者： Hendra Wijaksana I. N. S. Winaya Made Sucipta Ainul. Ghurri 1)Doctoral Study Program in Engineering Science Udayana University Kampus Jendral Sudriran Denpasar Bali-Indonesia 2)Mechanical Engineering Department Engineering Faculty Udayana University Kampus Bukit Jimbaran Denpasar Bali-Indonesia

An experimental investigation of the influences ammonia concentration variation to the performances of pump less ammonia-aqua absorption refrigeration system with water flooding evaporator is described. The heat generated in generator and refrigerating effect in evaporator, cooling capacity, coefficients of performance (COP) are investigated. The objective of this study is to investigate the characteristic and influences of the ammonia concentration variation to the performance of pump less absorption refrigeration system with water flooding evaporator as a refrigeration load.. In this research, the generator temperature has been setting constant in 80°C using electric heater, the ammonia concentration in 500 ml solution would be varied in 18%, 27%, 37%, 47%, and 59%. It is concluded that heat generated in generator and refrigerating effect in evaporator decrease with increasing ammonia concentration, while the cooling capacity and COP would increase with increasing ammonia concentration. As a result, it is found that increasing the ammonia concentration would effect on increasing of cooling capacity and COP. The highest the ammonia concentration, the highest cooling capacity and COP would be resulted. The highest cooling capacity and COP resulted respectively are 0.7180 kW and 0.829 at 59% ammonia concentration.

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Review on cold-formed steel beam-column, apex and eaves, and truss joint

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AIP Conference Proceedings 2024年第1期3116卷

作者： R. M. Fadel Satria Albimanzura Anis Saggaff Mahmood Md Tahir Kiagus Muhammad Aminuddin Doctoral Student of Engineering Science Study Program Doctoral Faculty of Engineering Sriwijaya University Indralaya Indonesia Civil Engineering Faculty of Engineering Sriwijaya University Indralaya Indonesia Institute for Smart Infrastructure and Innovative Construction (ISIIC) Construction Research Centre (CRC) School of Civil Engineering University Teknologi Malaysia Johor Bahru Malaysia

Light steel framing using the Cold-Formed Steel (CFS) sections is one of the Industrialized Building Systems (IBS) highly recommended for our construction industry; it not only contributes to speeding up construction time and reducing material usage but also guarantees the quality of the building. A relentless study has been conducted to achieve the appropriate configuration to ensure CFS popularity by introducing different types of joints applicable in constructing lightweight steel framing. A review of the CFS joint is provided in this study. The CFS joint is focused on the beam-column joint, apex and eaves, and truss joint. The study is mapped to establish research trends on CFS joints. Some areas show limited study and need future research on the proposed joints’ structural behavior aspects.

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Characteristic of beef tallow/rice husk charcoal/plaster composite phase change materials

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AIP Conference Proceedings 2023年第1期2568卷

作者： I. Made Astika I. Nyoman Suprapta Winaya I. Ketut Gede Wirawan Akhmad Herman Yuwono I. Dewa Gede Ary Subagia 1Doctoral Study Program of Engineering Science Faculty of Engineering Udayana University Kampus Sudirman Denpasar Bali 80234 Indonesia. 2Study Program of Mechanical Engineering Faculty of Engineering Udayana University Kampus Bukit Jimbaran Badung Bali 80361 Indonesia 3Department of Metallurgy and Materials Engineering Faculty of Engineering Universitas Indonesia Kampus Baru UI Depok Depok 16424 Indonesia

Composite materials are a combination of several materials to form a new material with specific properties. Chemical compatibility of the constituent materials is a factor that affects the characteristics of composite materials. Currently, composite phase change materials (PCM) are commonly applied as thermal energy storage systems. This study investigated the characteristics of beef tallow/rice husk charcoal/plaster PCM composite. The weight fraction of rice husk charcoal used was 10%. To prevent leakage of beef tallow from the composite structure, the researcher used polyvinyl acetate (PVAc) to cover the tallow/RHC composite before mixing it with plaster material. As much as 30% of the tallow/RHC/PVAc composite weight fraction is integrated into the plaster. PCM composite was made by using a direct incorporation method. The FTIR test results on the PCM composites produced showed good chemical compatibility among different components. The scanning electron microscope results showed the formation of microcapsules where the rice husk charcoal and polyvinyl acetate functions as a wrapper/capsule for beef tallow. This composite is suitable for application in building walls as thermal energy storage.

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Road infrastructure asset management strategy and its impact on the environment

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IOP Conference Series: Materials science and engineering 2020年第2期830卷

作者： K Priyatiningsih M Sutrisno Lecturer of Asset Management Study Program Politeknik Negeri Bandung Bandung 40012 Indonesia Student of Management Science Doctoral Program School of Post Graduate Universitas Pendidikan Indonesia Bandung Indonesia Lecturer of Civil Engineering Politeknik Negeri Bandung Bandung 40012 Indoenesia

The development of the economic sector is determined by services to the public through reforms that aim to place public satisfaction through the management of road infrastructure assets. Some research on road infrastructure assets still requires a deepening of studies related to the delivery of public services related to asset management systems. The purpose of this study is to find an appropriate road infrastructure asset management strategy through an integrated asset management system and asset management policies that can provide public satisfaction. This comprehensive approach to management strategies ensures that the performance of service provider assets is in line with the expectations of stakeholders including road users. This descriptive qualitative research is based on the perspective of road users as respondents, consisting of vehicle drivers from 50 transportation companies (people or goods) through interviews and observations. The results show aspects of asset performance based on the user's perspective there are five aspects, namely productivity, efficiency, effectiveness, use of resources and institutions and this performance is integrated in the asset management system related to policies from the management authority through service delivery namely quality and mobility, risk and use and maintenance of resources. The conclusion of this research is that road infrastructure asset services can be improved through the concept of road infrastructure asset management strategies in an integrated management system with five aspects of performance and more directed towards asset management policies related to the provision of road infrastructure asset services.

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An assessment of potential infiltration areas to support groundwater supply system in Jagakarsa, South Jakarta, based on Multi-Criteria Decision-Making (MCDM) analysis

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Case Studies in Chemical and Environmental engineering 2024年 10卷

作者： Suprapti, Suprapti Kusuma, Muhammad Syahril Badri Kardhana, Hadi Cahyono, Muhammad Doctoral Program of Civil Engineering Faculty of Civil and Environmental Engineering Institut Teknologi Bandung Jl. Ganesha No. 10 Jawa Barat Bandung 40132 Indonesia Study Program of Civil Engineering Faculty of Engineering Universitas Mercu Buana Jakarta Jl. Meruya Selatan No. 01 Kembangan Barat Jakarta 11650 Indonesia Water Resources Engineering Group Faculty of Civil and Environmental Engineering Institut Teknologi Bandung Jl. Ganesha No. 10 Jawa Barat Bandung 40132 Indonesia Civil Engineering Department Faculty of Engineering and Sciences Ibnu Khaldun Bogor University Jl. Sholeh Iskandar Km. 2 Kota Bogor Jawa Barat 16162 Indonesia Research Center for Ecohydrology Ecohydraulics and Engineering Science Bandung Jl. Babakan Jeruk 1 No. 100 Jawa Barat Bandung 40132 Indonesia

Jagakarsa is an urban area in South Jakarta, Indonesia, that uses groundwater for raw water because there are no clean water supply facilities. The significant increase in the need for clean water due to increasing urbanization threatens groundwater availability to maintain the balance of the surrounding environment. Natural conditions with a deep layer of clay and a dense built environment further increase runoff capacity because water has difficulty seeping into the soil. The intense extraction of groundwater without balancing groundwater recharge results in land subsidence. Until now, there has been no research on this issue. Thus, our research is necessary. This research aims to assess the potential of groundwater infiltration areas in Jagakarsa. Due to limited data, as a first step, we used a qualitative model with MCDM analysis (AHP and MIF methods) integrated with GIS to map potential groundwater recharge areas. The AHP method is explained in detail with a matrix system formula, readers can understand the calculation steps more easily. This study uses five influencing factors: geological formation, land use, slope, rainfall, and soil type. The results show that most study locations have low potential (AHP 74.49 % and MIF 75.25 %) for groundwater recharge. This groundwater recharge potential map was validated using groundwater level measurements. The accuracy of the AHP is 74.51 %, and the MIF method reaches 75.26 %. Therefore, further research is needed to obtain appropriate and effective technology for maintaining groundwater availability. © 2024 The Authors

关键词： AHP-MIF-GIS Groundwater Jagakarsa-South Jakarta MCDA Potential infiltration area

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Activated carbon characteristics of tabah bamboo that physically activated under different activation time

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IOP Conference Series: Materials science and engineering 2019年第1期539卷

作者： D N K P Negara T G T Nindhia I W Surata M Sucipta F Hidajat Doctoral Study Program of Engineering Science Faculty of Engineering Udayana University Kampus Sudirman Denpasar-Bali Indonesia Mechanical Engineering Department of Udayana University Street of Bukit Jimbaran Badung Bali Indonesia PPPTMGB 'Lemigas' Jl. Ciledug Raya Kav. 109 Jakarta Selatan 12230

Activated carbon is a versatile porous material that widely applied to purify, deodorize, decolorize, remove or reduce some gases harmful constituents and storage of gas. For different application different characteristics of activated carbon is required. This paper concerns to find out the characteristics of activated carbons derived from tabah bamboo (Gigantochloc nigrociliata) that physically activated with different activation holding time. Prepared tabah bamboo was carbonized by heating up to the temperature of 800 °C for two hours. The char produced was powdered and then activated physically by heating up to 800 °C, soaked at that temperature during each 1, 1.5 and 2 hours under 100 mL/min N2 flow. Activated carbons manufactured were characterized by proximate and ultimate analyses and SEM observation. The results show that the highest fix carbon (82.52%) and lowest ash (5.91 %) was obtained at 1 hour soaking time with moisture and volatile contents were 3.56% and 8.00 % respectively; the highest carbon (C) content of 84.16 % was yielded at soaked time of 1.5 hours; SEM observation shows that there were significant differences of morphology structure between raw material and activated carbons for all of the soaking time variations. The pores structures have been formed in the activated carbons produced.

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Evaluating the impacts of environmental and human health of the critical minerals mining and processing industries in Indonesia using life cycle assessment

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Case Studies in Chemical and Environmental engineering 2024年 10卷

作者： Wahyono, Yoyon Sasongko, Nugroho Adi Trench, Allan Anda, Martin Hadiyanto, Hadiyanto Aisyah, Nyayu Anisah, Anisah Ariyanto, Novy Kumalasari, Isnaeni Putri, Virny Zasyana Eka Lestari, Mutia Citrawati Panggabean, Lambas Parlaungan Ridlo, Rohmadi Sundari, Sundari Suryaningtyas, Anissa Dewi Novianti, Endah Dwi Hakim, Muhammad Raihan Farras Prihatin, Anggara Lomak Matin, Hashfi Hawali Abdul Research Center for Sustainable Production System and Life Cycle Assessment National Research and Innovation Agency - BRIN Prof. BJ. Habibie Complex Area Banten Tangerang Selatan 15314 Indonesia Energy Security Graduate Program Republic of Indonesia Defense University IPSC Sentul Area West Java 16810 Indonesia Centre for Exploration Targeting School of Earth Sciences The University of Western Australia 35 Stirling Highway Crawley 6009 WA Australia UWA Business School 35 Stirling Highway Crawley 6009 WA Australia Environmental Engineering Murdoch University Murdoch 6150 WA Australia Doctoral Program of Environmental Science School of Postgraduate Studies Diponegoro University Central Java Semarang 50241 Indonesia Department of Chemical Engineering Faculty of Engineering Diponegoro University Central Java Semarang 50275 Indonesia Department of Mechanical Engineering Vocational School Gadjah Mada University Sleman Yogyakarya 55281 Indonesia Study Program of Environmental Science Faculty of Mathematics and Natural Science Universitas Sebelas Maret Central Java Surakarta 57126 Indonesia

The critical minerals industries in Indonesia may pose possible environmental and human health risks due to the release of pollutants into soil, water, and air, as well as the use of materials and energy. This study investigates the possible environmental and human health impacts of Indonesia's nickel, gold, copper, tin, and bauxite mining and processing industries. This study utilizes the latest version of the OpenLCA software, version 2.0, in combination with the Ecoinvent 3.8 database. To evaluate potential environmental consequences and health effects on humans, CML-IA Baseline and Environmental Priority Strategies (EPS) are employed in product development. The EPS system was developed utilizing a hierarchical methodology with the objective of furnishing the product developer with data regarding the financial impact of human health impairment resulting from a particular product development. The production of one tonne of gold, nickel, bauxite, tin, and copper results in the emission of 7.34.E+07, 4.61.E+04, 3.10.E+04, 1.02.E+04, 8.01.E+03 kg CO₂ eq/t, respectively, contributing to global warming. This production is associated with asthma cases of 7.79.E+01 (gold industry), 2.21.E−03 (copper industry), 1.81.E−03 (tin industry), 9.21.E−04 (nickel industry), and 4.71.E−06 (bauxite industry) Personyears/t. Electricity consumption and the release of carbon dioxide are the main factors contributing to global warming. The primary cause of asthma cases is the utilization of fuel oil and electricity. Power plant chimneys can employ various technologies, such as cyclones, bag filters, and scrubbers, to mitigate the release of polluting gas emissions. The critical mineral industry must prioritize handling and governing of steam power facilities to minimize their negative effects on the environment and human health. © 2024 The Authors

关键词： Critical minerals industries Environmental impacts Human health impacts Life cycle assessment

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Systems thinking on renewable energy: A bibliometric analysis

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AIP Conference Proceedings 2023年第1期2734卷

作者： Dindin Nasrudin Agus Setiawan Dadi Rusdiana Liliasari Science Education Doctoral Program Universitas Pendidikan Indonesia Bandung Indonesia Physics Education Study Program UIN Sunan Gunung Djati Bandung Indonesia Department of Mechanical Engineering Education Universitas Pendidikan Indonesia Bandung Indonesia Department of Physics Education Universitas Pendidikan Indonesia Bandung Indonesia Department of Chemistry Education Universitas Pendidikan Indonesia Bandung Indonesia

Energy is a systematic problem involving many fields and disciplines. Discourse about it requires systems thinking. This research aims to reveal trends and future work related to system thinking on renewable energy. The method used is a bibliometric analysis of the Scopus database using VOSviewer software. Through the selection process, 284 documents deemed relevant were selected from journal articles and conference proceedings. Through VOSviewer analysis, 4 clusters of related keyword groups are shown. Four very influential words in this research theme are systems theory with 224 occurrences, renewable energy resources with 142 occurrences, renewable energy with 112 occurrences, and system dynamics with 102 occurrences. Through network visualization, the relationship between concepts both within one cluster and between clusters is shown. The visualization overlays is used as a basis of mapping the future work related to system thinking on renewable energy which include renewable energy resources, system theory, system dynamics, alternative energy, sustainable development, decision making, and renewable energy technology. This study concludes that bibliometric analysis through VOSviewer is proven to be able to show trends and future work for systems thinking on renewable energy research.

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Modeling the number of confirmed cases of COVID-19 in East Java using negative binomial regression based on least square spline estimator

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AIP Conference Proceedings 2024年第1期3083卷

作者： Arip Ramadan Nur Chamidah I. Nyoman Budiantara Student of Doctoral Study Program of Mathematics and Natural Sciences Faculty of Science and Technology Airlangga University Surabaya 60115 Indonesia. Department of Information System School of Industrial and System Engineering Telkom University Surabaya 60231 Indonesia. Department of Mathematics Faculty of Science and Technology Airlangga University Surabaya 60115 Indonesia. Research Group of Statistical Modeling in Life Science Faculty of Science and Technology Airlangga University Surabaya 60115 Indonesia. Department of Statistics Faculty of Sciences and Data Analytics Sepuluh Nopember Institute of Technology Surabaya 60111 Indonesia.

The East Java Province has experienced a significant surge in number of confirmed cases of COVID-19. This study endeavors to investigate the potential correlation between weather conditions and the incidence of number of confirmed cases of COVID-19 in East Java. To achieve this, a nonparametric regression model, specifically, the Negative Binomial Regression (NBR) model based on the least squares spline estimator, was utilized. The outcomes of the study indicate that the Mean Absolute Percentage Error (MAPE) of nonparametic regression model is 0.30. Meanwhile, the MAPE for the parametric regression model is 0.34. The results show that a nonparametric regression model approach is better than parametric regression model approach. The study establishes that the truncated spline estimator based NBR model represents the best fit, with an MLCV value of -256.71. The findings of the study suggest that a temperature less than 21.75°C is associated with a decrease of 13.28 number of confirmed cases of COVID-19 per each 1°C increase, while a temperature between 21.75°C and 25.78°C is linked to an increase of 6.85 number of confirmed cases of COVID-19 per each 1°C increase. In contrast, a temperature greater than 25.78°C is associated with a decrease of 139.42 number of confirmed cases of COVID-19 per each 1°C increase. Similarly, a wind speed less than 5.57 m/s is related to a decrease of 12.99 number of confirmed cases of COVID-19 per each 1 m/s increase, whereas a wind speed between 5.57 m/s and 8.99 m/s is associated with a decrease of 10.29 number of confirmed cases of COVID-19 per each 1 m/s increase. Furthermore, a wind speed greater than 8.99 m/s is linked to a decrease of 19.16 number of confirmed cases of COVID-19 per each 1 m/s increase. The study provides evidence that higher temperatures and wind speeds result in a slower rise in the incidence of the number of confirmed cases of COVID-19. Consequently, it is recommended that the local government remains vigilant du

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