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Advancements in Geopolymer Concrete for Marine Infrastructure: An Optimization of Performance Considering Workability, Compressive Strength, Capillary Water Absorption, Porosity, and Chloride Migration

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Iranian Journal of Science and Technology - Transactions of Civil engineering 2024年 1-14页

作者： Shahedan, Noor Fifinatasha Hadibarata, Tony Jusoh, Muhammad Noor Hazwan Isia, Ismallianto Bouaissi, Aissa Juwono, Filbert Hilman Nawawi, Natasha Ahmad Kusumaningrum, Hermin Pancasakti Muslim, Abrar Hidayat, Topik Environment Engineering Program Curtin University Malaysia Miri CDT 250 Malaysia School of Engineering University of Plymouth Plymouth PL4 8AA United Kingdom Department of Electrical and Electronic Engineering Xi’an Jiaotong – Liverpool University Suzhou China School of Mechanical Engineering College of Engineering Universiti Teknologi MARA Shah Alam 40450 Malaysia Biotechnology Study Program Department of Biology Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Syiah Kuala Banda Aceh Indonesia Biology Study Program Faculty of Mathematics and Science Education Universitas Pendidikan Indonesia Bandung Indonesia

This research investigates the effectiveness of geopolymer concrete incorporating fly ash in environments rich in chlorides;in contrast to conventional Portland cement concrete (OPC). The study emphasizes essential characteristics such as workability, mechanical strength, capillary water absorption, open porosity, and chloride migration. The experiments demonstrated that geopolymer concrete exhibits a 30% enhancement in slump values, reflecting improved workability, and its compressive strength rose by 14.90–23.94% when compared with OPC. A significant reduction in binder content led to a notable decrease in capillary water absorption, highlighting a positive impact on long-term durability. With time, geopolymer concrete showed a reduction in open porosity and chloride migration coefficient, indicating better resistance to chloride penetration in marine settings. Although these outcomes underscore the potential of geopolymer concrete to improve structural durability, especially in marine infrastructure, additional optimization is required to tackle its relatively higher capillary water absorption and chloride migration during the initial stages. These results contribute to the ongoing investigation of sustainable building materials, offering valuable insights into geopolymer concrete’s ability to endure severe chloride exposure and serve as a durable solution for corrosion management in marine infrastructure. © The Author(s), under exclusive licence to Shiraz University 2024.

关键词： Durability Geopolymer concrete Marine environments Mix design Sustainable construction

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DIFFERENCES IN THE GAIT CHARACTERISTICS OF PATIENTS WITH DIABETES AND PERIPHERAL NEUROPATHY COMPARED WITH AGE-MATCHED CONTROLS - RESPONSE

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PHYSICAL THERAPY 1994年第4期74卷 312-313页

作者： MUELLER, MJ MINOR, SD SAHRMANN, SA SCHAAF, JA STRUBE, MJ MJ Mueller PhD PT is Assistant Professor Program in Physical Therapy Washington University School of Medicine 660 S Euclid Box 8083 St Louis MO 63110 (USA). SD Minor PhD PT is Assistant Professor Program in Physical Therapy Washington University School of Medicine. SA Sahrmann PhD PT FAPTA is Associate Professor Program in Physical Therapy Washington University School of Medicine. JA Schaaf PhD is Visiting Research Associate and Lecturer Department of Mechanical and Aeronautical Engineering University of California Davis CA 95616. He was Hunter Assistant Professor of Mechanical Design Mechanical Engineering Washington University at the time of this study. MJ Strube PhD is Professor of Psychology Washington University.

Background and *** with diabetes and peripheral neuropathy have a high incidence of injuries while walking. Biomechanical analysis of their walking may lead to treatments to reduce these injuries. The purpose of this study was to compare (1) the gait characteristics, (2) the plantar-flexor peak torques, and (3) the ankle range of motion of subjects with diabetes mellitus (DM) and peripheral neuropathy with those of age-matched *** subjects, 10 with DM and a history of peripheral neuropathy (DM group) (mean age=58 years, SD=15, range=35–75) and 10 subjects without diabetes (NODM group) (mean age=57 years, SD=11, range=37–68), were *** following data were collected on all subjects: ankle joint mobility, plantar-flexor peak torque (ankle strength), kinematics of the trunk and lower extremity during normal walking, and ground reaction forces. Moments and power at the ankle, knee, and hip during walking were calculated using a two-dimensional link-segment *** DM group subjects showed less ankle mobility, ankle moment, ankle power, velocity, and stride length during walking than the NODM group subjects. A significant decrease in ankle strength and mobility appeared to be the primary factor contributing to the altered walking patterns of the DM *** and *** DM group subjects appeared to pull their legs forward using hip flexor muscles (hip strategy) rather than pushing the legs forward using plantar-flexor muscles (ankle strategy), as seen in the NODM group subjects. Implications for treatment are presented to attempt to reduce the number of injuries during walking in patients with DM and peripheral neuropathy.

关键词： Biomechanics Diabetes mellitus Gait analysis Joint mobility Kinetics Muscle performance

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Gravitational Water Vortex Hydropower: Experimental Investigation of Free Surface Wave in Water Intake Channel

Gravitational Water Vortex Hydropower: Experimental Investig...

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2020 International Conference on Sustainable Energy engineering and Application, ICSEEA 2020

作者： Huwae, Reza Susatyo, Anjar Subekit, Ridwan Arief Sudibyo, Henny Khaerudini, Deni Shidqi Mercu Buana University Program of Study Nagister in Mechanical Engineering Jakarta Indonesia Research Centre for Electrical Power and Mechatronics Bandung Indonesia Research Center for Physics Serpong Indonesia Department of Physics FMIPA Universitas Indonesia Depok Indonesia

ISBN: (纸本)9781728188492

Development program for construction of irrigation channel gives big opportunity for development of renewable energy from small low head hydropower source. The use of hydropower gives no negative impact to environment, especially for greenhouse emission. A gravitational vortex hydropower is the object of this study, with the focus on the water intake channel using rectangular geometry. An experimental study was conducted to find the influencing parameters on the intake section of the gravitational vortex hydropower. A set of parameters were varied to determine which parameters affecting the water surface at the intake channel. By analyzing the results of the experiments, the influence of parameters on the water intake channel of gravitational vortex hydropower was found. A performance curve for differentiation of flow type and identification of surface contour has been made. Based on the results of the experiment, placing a strainer at 5 cm distance gave 60% higher output power since this setting could reduce the wave speed. Recommendation to have further study in non-dimensional parametric should be considered for increasing efficiency of the gravitational vortex hydropower. © 2020 IEEE.

关键词： Vortex flow

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Mini-micro hydropower plants progress in Indonesia: The effective and suitable projects for isolated and remote communities

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Test engineering and Management 2020年 83卷 1509-1514页

作者： Yunus, A. M. Shiddiq Apollo Mulyadi, Musrady Arifuddin, M. Pakka, Hariani M. Energy Conversion Study Program Mechanical Engineering Dept Politeknik Negeri Ujung Pandang Jl. Perintis Kemerdekaan KM. 10 Makassar90245 Indonesia Ministry of Energy and Mineral Resources of Indonesia Jl. Medan Merdeka Selatan No. 18 Jakarta Pusat10110 Indonesia Electrical Engineering Department Moslem University of Indonesia Jl. Urip Sumihardjo Makassar Indonesia

In 2017 Indonesia has reached about 91.16% of national electrification ratio. The most challenging part of increasing the electrification ratio is the ineffective cost and long term revenue of installing long distribution and transmission lines to the isolated and remote areas. To achieve the 100% electrification ratio in 2020, the Indonesian government has constructed more micro hydropower plants (MHPP) scale to supply power to isolated and remote areas. The total hydropower plant that has been installed all around Indonesia since 2016 is about 11% of the total available potency. The projects were economically effective as they normally run with the collaboration among, national government, local authority and local communities. The mini-micro hydropower projects that were running from 2011 to 2015 have been conducted in two main scheme, the private sector or so-called independent power producers (IPPs) and through government funding. The MHPP projects implementation of course was facing in between benefits and shortcomings. Some of the benefits of MHPP are low cost project, environment benign and long live operation. However, the drawbacks of MHPP might include specific site requirement, social conflict, non-skilled operator that might harm himself, and operation is depending on the local climate. The win-win solution should be come across for MHPP projects to accommodate between the benefits and the short-comings. © 2020 Mattingley Publishing. All rights reserved.

关键词： Hydroelectric power plants

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A Parametric of Basin Geometry of Gravitational Water Vortex Power Plant

A Parametric of Basin Geometry of Gravitational Water Vortex...

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2020 International Conference on Sustainable Energy engineering and Application, ICSEEA 2020

作者： Huwae, Reza Susatyo, Anjar Subekti, Ridwan Arief Sudibyo, Henny Khaerudini, Deni Shidqi Mercu Buana University Program of Study Nagister in Mechanical Engineering Jakarta Indonesia Research Centre for Electrical Power and Mechatronics Bandung Indonesia Research Center for Physics Serpong Indonesia Department of Physics FMIPA Universitas Indonesia Depok Indonesia

ISBN: (纸本)9781728188492

Energy demand is increasing and it raise a climate change issue. Greenhouse emissions, depleted fossil energy resources, increasing fossil energy cost are reasons to maximize the utilization of renewable energy source. Hydropower extend an alternative energy source to cover the growing energy demand and release no emission at the same time for maintaining the climate change. In recent years, major focus of hydropower research is moving to small hydropower, as large hydropower opportunities are exploited and have high capital expenditure to build. A water vortex stream is a common phenomenon that we can see everyday life. Water flow out from the bathtub through outlet or water flow down in the sink after we finish washing the dishes, that is what we call vortex flow. and is a free-surface flow, homogenous fluid that contained water and air. This water vortex can be applied in low head small hydropower plant, recently known as gravitational water vortex power plant. River off Gravitational Water Vortex power plant (GWVPP) is one of low head turbine that can be used to generate electricity in small scale, pico-hydro. This study is focus on basin geometry. Models are developed to investigate the outlet diameter, depth discharge and basin geometry. It is found out that parameter of the basin should refer to source, which are flow rate, and the head of the water. It shows that spiral geometry for the basin gives symmetric and strong vortex and can be used as an alternative of conical basin. © 2020 IEEE.

关键词： Geometry

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The development of the model of influence of sociodemographic characteristics and disaster experience toward household preparedness for facing landslide in Bogor regency 2

The development of the model of influence of sociodemographi...

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2nd International Conference on Disaster and Management 2020, ICDM 2020

作者： Saputra, P.D. Rahmawati, C. Karuniakhalida, P. Purnomo, K.S.H. Larosa, E. Military Building Construction Engineering Study Program Faculty of Military Engineering Indonesia Defense University Bogor Indonesia Industrial Engineering Department Faculty of Industrial Technology Universitas Dirgantara Marsekal Suryadarma Jakarta Indonesia Mathematic for Education Program Faculty of Teacher Training and Education Universitas Riau Riau Indonesia Master of Management Program Universitas Teknologi Yogyakarta Yogyakarta Indonesia Mechanical Engineering Education Faculty of Teacher Training and Education Universitas Negeri Yogyakarta Yogyakarta Indonesia

Indonesia has a high tendency of having landslides. Bogor is one of regency which is very prone to landslide disaster due to high rainfall. Landslides are a very dangerous threat to public safety. The preparedness can build disaster resilient communities that can support the national resilience. Sociodemographic characteristic and disaster experience are determining factors for the success of preparedness. The purpose of this research is to develop a model of the influence of sociodemographic characteristics and disaster experience toward household preparedness for facing landslide. This research is done in Cibadak Village, Sukamakmur Bogor. This research uses a quantitative approach with 100 sample of households. Multiple linear regression technique is used for analyzing the model. The results of the research showed that household preparedness is significantly influenced by sociodemographic characteristics which is education (p = 0.000), meanwhile age, income and the number of family member don't significantly influence. Beside that the household preparedness is also greatly influenced by disaster experience too (p = 0.000). Education influence on household preparedness for facing landslide as much as 38.81% and the disaster experience is 52.85%. © Published under licence by IOP Publishing Ltd.

关键词： Disasters

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Activated carbon characteristics of tabah bamboo that physically activated under different activation time 1

Activated carbon characteristics of tabah bamboo that physic...

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1st International Conference on Design, Energy, Materials and Manufacture, ICDEMM 2018

作者： Negara, D.N.K.P. Nindhia, T.G.T. Surata, I.W. Sucipta, M. Hidajat, F. Doctoral Study Program of Engineering Science Faculty of Engineering Udayana University Kampus Sudirman Denpasar-Bali Indonesia Mechanical Engineering Department Udayana University Street of Bukit Jimbaran Bali Badung Indonesia PPPTMGB Lemigas Jl. Ciledug Raya Kav. 109 Jakarta Selatan12230 Indonesia

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. © Published under licence by IOP Publishing Ltd.

关键词： Activated carbon

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Effects of SMES on Dynamic Behaviors of Type D-Wind Turbine Generator-Grid Connected during Short Circuit

Effects of SMES on Dynamic Behaviors of Type D-Wind Turbine ...

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IEEE Power and Energy Society General Meeting

作者： A. M. Shiddiq Yunus A. Abu-Siada M. A. S. Masoum Department of Mechanical Engineering Energy Conversion Study Program State Polytechnic of Ujungpandang Department of Electrical and Computer Engineering Curtin University

ISBN: (纸本)9781457710001

Application of Superconducting Magnetic Energy Storage unit with Hysteresis Current Control-Fuzzy Logic to improve the performance of Wind Turbine Generator-Grid connected during short circuit is presented. Five 2 MW Type D-Wind Turbine Generator connected to a grid is simulated using SIMULINK/MATLAB program. The Superconducting Magnetic Energy Storage unit consists of a Voltage Source Converter and DC-DC Chopper that are controlled by Hysteresis Current Control and Fuzzy Logic Controller respectively. Simulation results show that the proposed control algorithm of Superconducting Magnetic Energy Storage unit is effective in saving some MWs of Type D-Wind Turbine Generator production during occurrence of short circuit in the line.

关键词： Fuzzy Logic Hysteresis Current Control Superconducting magnetic energy storage Type D-Wind Turbine Generator SUPERCONDUCTING MAGNETIC ENERGY STORAGE Fuzzy logic Wind Generators Short circuits voltage source converter turbogenerators Computer algorithms fuzzy logic controller

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Calcium release and physical properties of modified carbonate apatite cement as pulp capping agent in dental application

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Biomaterials Research 2018年第1期22卷 346-351页

作者： Zakaria, Myrna Nurlatifah Cahyanto, Arief El-Ghannam, Ahmed Department of Endodontology and Operative Dentistry Program Study of Dentistry Faculty of Medicine Universitas Jenderal Achmad Yani Cimahi Indonesia Department of Dental Materials Science and Technology Faculty of Dentistry Universitas Padjadjaran Sumedang-Jatinangor Indonesia Department of Mechanical Engineering and Engineering Science The University of North Carolina at Charlotte Charlotte NC United States

Background: Carbonate apatite (CO3Ap) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell f... 详细信息

Background: Carbonate apatite (CO₃Ap) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell function while, CO₃Ap induce apatite crystal formation with good adaptation providing good seal between cement and the bone. Together, these materials will add favorable properties as a pulp capping material to stimulate mineral barrier and maintain pulp vitality. The aim of this study is to investigate modification of CO₃Ap cement combined with SCPC, later term as CO₃Ap-SCPC cement (CAS) in means of its chemical (Calcium release) and physical properties (setting time, DTS and pH value). Methods: The study consist of three groups;group 1 (100% calcium hydroxide, group 2 CO₃Ap (60% DCPA: 40% vaterite, and group 3 CAS (60% DCPA: 20% vaterite: 20% SCPC. Distilled water was employed as a solution for group 1, and 0.2 mol/L Na₃PO₄ used for group 2 and group 3. Samples were evaluated with respect to important properties for pulp capping application such as pH, setting time, mechanical strength and calcium release evaluation. Results: The fastest setting time was in CO₃Ap cement group without SCPC, while the addition of 20% SCPC slightly increase the pH value but did not improved the cement mechanical strength, however, the mechanical strength of both CO₃Ap groups were significantly higher than calcium hydroxide. All three groups released calcium ions and had alkaline pH. Highest pH level, as well as calcium released level, was in the control group. Conclusion: The CAS cement had good mechanical and acceptable chemical properties for pulp capping application compared to calcium hydroxide as a gold standard. However, improvements and in vivo studies are to be carried out with the further development of this material. © The Author(s).

关键词： Carbonate apatite CO3Ap-SCPC cement Pulp capping Silica-calcium phosphate composite

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Preliminary study of Microwave Metamaterial Based on Cylinder-Shaped for Sensor

Preliminary Study of Microwave Metamaterial Based on Cylinde...

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International Conference on Instrumentation Control and Automation (ICA)

作者： Hadi Teguh Yudistira Muhammad Asril Mechanical Engineering Study Program Institut Teknologi Sumatera (ITERA) South Lampung Lampung Indonesia Biology Study Program Institut Teknologi Sumatera (ITERA) South Lampung Lampung Indonesia

A metamaterial is an artificial material that can be used for several applications such as a sensor. Microwave metamaterial is one of the reasonable candidates for sensor due to relatively good resolution for detection and easy fabrication process. In this work, the cylinder-shaped and the inverted cylinder-shaped were considered as unit cell metamaterial. Paper was used as a dielectric substrate on metamaterial design. The sample phase is a liquid phase which could penetrate on paper thus could change the relative permittivity of paper. The highest transmission frequency was shifted from 3.81 to 3.89 for cylinder-shaped and also the lowest reflection frequency for cylinder-shaped. The highest transmission frequency was shifted from 3.33 to 3.43 for cylinder-shaped, and also the lowest reflection frequency for cylinder-shaped. The resolution of alteration sample detection on metamaterial is around 0.02 GHz for cylinder-shaped and inverted cylinder-shaped.

关键词： Metamaterials Reflection Permittivity Electromagnetic scattering Microwave technology Microwave measurement Resonant frequency

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