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Solution of Helmholtz eigenvalue problems with non-regular domains using the direct interpolation technique

Partial Differential Equations in Applied Mathematics 2025年 14卷

作者： Carlos Friedrich Loeffler Luciano de Oliveira Castro Lara Hercules de Melo Barcelos João Paulo Barbosa Mechanical Engineering Post-Graduate Program Federal University of Espírito Santo UFES CT Av. Fernando Ferrari 540-Bairro Goiabeiras 29075-910 Vitória ES Brazil National Institute of Metrology Quality and Technology INMETRO CEP 25250-020 Duque de Caxias RJ Brazil Federal Institute of Espírito Santo IFES Campus São Mateus Rodovia BR 101 Norte Km 58 Litorâneo 29932540 São Mateus ES Brazil

This work aims to evaluate the performance of the Direct Interpolation Boundary Element Method solving Helmholtz problems that present no regular geometric shapes. Using the radial basis functions, the Direct Interpolation Method approximates the non-self-adjoint kernel of the domain integral equations, which appear in many partial differential equations of mathematics, physics, and engineering. Modeling the Helmholtz Equation, the Direct Interpolation Method approximates the inertia term by a sequence of radial basis functions. The technique has been used successfully in Poisson, Diffusive-advective, and Helmholtz problems, considering regular geometries and taking analytical solutions as a reference for performance evaluation. This paper evaluates the effects of the slenderness of the domain and the introduction of cuts on the boundary regarding the accuracy. Reference solutions are generated through Finite Element Method simulations using fine meshes.

关键词： Boundary elements method Helmholtz’s equation Eigenvalues problems Irregular geometric conformation

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On the Performance of Industrial Wireless Sensor Networks: Channel Hopping vs. Channel Adaptive Protocols 1

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6th International Conference on Sensor Networks, SENSORNETS 2017 and 7th International Conference on Sensor Networks, SENSORNETS 2018

作者： Gomes, Ruan D. Benavente-Peces, Cesar Alencar, Marcelo S. Queiroz, Diego V. Fonseca, Iguatemi E. Post-Graduate Program in Electrical Engineering Federal University of Campina Grande Campina Grande Brazil Informatics Coordination Federal Institute of Paraiba Guarabira Brazil Signal Theory and Communications Department Universidad Politecnica de Madrid Madrid Spain Informatics Center Federal University of Paraiba Joao Pessoa Brazil

ISBN: (数字)9783030301101

ISBN: (纸本)9783030301095

The standard IEEE 802.15.4e shows several improvements which makes it outperforming the predecessor IEEE 802.15.4 standard. A remarkable improvement is the use of multiple channels and the capability to choose the most convenient depending on the network links state. Hence, different techniques can be provisioned to dynamically select the most appropriate channel for establishing the link through an adaptive mechanism. During the contention-free periods, the Time-Slotted Channel Hopping (TSCH) mode is based on channel hopping while the Deterministic and Synchronous Multi-channel Extension (DSME) mode uses either channel hopping or channel adaptation. In scenarios where channel diversity techniques are used for channel adaptation nodes links are established using the same channel as long as the channel quality (SNR) is high enough. In consequence to guarantee link best performance, its quality must be measured periodically to decide whether continue in the same channel of switch to a better performance one. Our investigation focuses on the analysis of the performance of three different approaches which pretend to take advantage of the multichannel capabilities of the new standard, based on the DSME protocol: CH-DSME which is based on a simple channel hopping mechanism, CA-DSME which employs channel adaptation, and a novel hybrid approach (H-DSME) which combines channel hopping and channel adaptation. This investigation shows that, in an industrial environment, the H-DSME outperforms both CH-DSME and CA-DSME approaches. In this work, the Castalia simulator was used to perform the simulations, using a reliable simulation model, which captures the characteristics of the wireless channel in industrial environments in long range basis. The analysis demonstrates that channel adaptation is better than channel hopping for unicast packets transmission, when links quality are continuously measured. Nevertheless, the coordinator transmit packets in broadcast mode, it is demonst

关键词： Wireless sensor networks

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Design and implementation of the quality of mineral water test equipment using fuzzy logic method based on Internet of Things

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IOP Conference Series: Materials Science and engineering 2021年第4期1098卷

作者： E Kurniawan S Sumaryo F Budiman A Happy B S Aprillia Post Graduate Program of Chemistry Department Faculty of Mathematics and Natural Sciences Padjadjaran University Jalan Raya Bandung-Sumedang Jatinangor Sumedang Indonesia School of Electrical Engineering Telkom University Bandung Indonesia

Water is a chemical compound that is very important for living things on this earth. The function of mineral water for human life cannot be replaced by other compounds. To ensure that it can be used for needs, quality monitoring must be carried out continuously. This study aims at designing mineral water quality test equipment using the fuzzy logic algorithm method that is equipped with a pH sensor, TDS sensor, temperature sensor, LDR sensor, LCD, Wi-Fi module. The simulation results show that an average value of pH sensor of 8.5 - 12, TDS sensor of 300 - 350 ppm, sensor temperature of 22-25oC, and the resistance of the LDR of 110-170 Ohm sensor for daytime while the evenings of 920 - 970 Ohm. The several types of water tested was 5 areas around Bandung and Telkom University Dormitories. The accuracy of this tool reaches of 80%, it can be seen from the calibration results.

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Analysis of Lead (Pb) and Zinc (Zn) Content in Sediments and Faunus ater at Bale Lhoknga Aceh Besar District 1

Analysis of Lead (Pb) and Zinc (Zn) Content in Sediments and...

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1st International Conference on Education, Science and Technology, ICON-EST 2018

作者： Agustina, Rahmi Sarong, M. Ali Yulianda, Fredinan Suhendrayatna Rahmadi Lelifajri Graduate School of Mathematics and Applied Sciences Syiah Kuala University Banda Aceh23111 Indonesia Departement of Biology Faculty of Teacher Training and Education Jabal Ghafur University Sigli24171 Indonesia Departement of Biology Faculty of Teacher Training and Education Syiah Kuala University Banda Aceh23111 Indonesia Departement of Water Resources Management Faculty of Fisheries and Marine Sciences Bogor Agricultural University Bogor16680 Indonesia Department of Chemical Engineering Faculty of Engineering Syiah Kuala University Banda Aceh23111 Indonesia Department of Chemistry Faculty of Mathematics and Science Post Graduate Program Syiah Kuala University Banda Aceh23111 Indonesia Department of Chemistry Faculty of Mathematics and Sci. Post Graduate Program Syiah Kuala Univ. Banda Aceh23111 Indonesia

Faunus ater is a favoritemollusca that is often found on the Bale River. Local people use these snails as food for consumption along with their main food. Bale River itself is located adjacent to the cement factory, used water washing machines distributed to the river is feared to support the presence of lead (Pb) and zinc (Zn) metals in the river. This study aims to analyze the relationship of Pb and Zn content in sediments to the content of Pb and Zn in Faunus ater. Data collection was carried out in Februari until April 2018. The relationship between Pb and Zn content in sediments with Pb and Zn content in the body of Faunus ater was analyzed by correlation analysis. The results of the data analysis showed that the metal content of Pb and Zn in sediment and Faunus aterwere found to vary. The highest Pb content in sediment was found at station 2 in March, amounting to 32.87 mg / kg. while the highest Zn content was found at station 1 in March amounting to 84 mg / kg. The relationship of heavy metals Pb and Zn in sediments to the content of Pb and Zn in the body of Faunus ater showed a negative correlation. The conclusion of this study is that there is no correlation between the content of Pb and Zn heavy metals in sediments on the content of lead Pb and Zn in the body of Faunus ater at the Bale Lhoknga River in Aceh Besar District. © Published under licence by IOP Publishing Ltd.

关键词： Rivers

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Effect of Method and Duration of Curing on the Compressive Strength of the Lime-Fly Ash Geopolymer Concrete

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Journal of Physics: Conference Series 2020年第1期1594卷

作者： Andi Arham Adam Sri Nur Akifa Atur P.N. Siregar Mustofa Department of Civil Engineering Tadulako University Post-Graduate Program Tadulako University Department of Mechanical Engineering Tadulako University

The use of lime to produce ambient cured Geopolymer concrete is one of a practical solution to avoid heat curing in the production of geopolymer concrete. The addition of lime in the geopolymer system will add another hardened mechanism, i.e. hydration in addition to condensation-polymerisation. This research aims to determine the influence of air and water curing on the strength of geopolymer concrete which uses class F fly ash and lime as raw materials. The geopolymer concrete was produced by varying the activator (sodium silicate and sodium hydroxide) with the variation of the activator to binder ratio of 0.45, 0.50, 0.55, and 0.60. Five per cent of the fly ash was replaced by slaked lime and the water added to the mix to maintain the ratio of water to solid (activator + binder) to 0.32. The test specimens were 100 mm dia x 200 mm height cylinder. Water-immersion curing was performed for 7, 14, and 21 days and the compressive strength test was done at 28 days. The results show that there is a difference in the curing process between the geopolymer concrete and the normal concrete. In the geopolymer concrete, there is a decrease in compressive strength if soaked for seven days and recovered with the increase in the age of immersion. Whereas for normal concrete, the compressive strength continues to increase with increasing age of immersion.

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Perception Analysis of Airport Noise on Environment, Sosial, and Economic at Halim Perdana Kusuma Airport

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IOP Conference Series: Earth and Environmental Science 2021年第1期794卷

作者： Wahyu Sardjono Haryoto Kusnoputranto Bagus Ferry Agrayanto Tri Edhi Budhi Soesilo Gabriel A. Kristanto Information Systems Management Department BINUS Graduate Program - Master of Information Systems Management Bina Nusantara University Jakarta Indonesia 11480 Department of Environmental Health Faculty of Public Health University of Indonesia Indonesia Post Graduate Program School of Environmental Science University of Indonesia Jakarta Indonesia Environmental Engineering Department Faculty of Engineering University of Indonesia Jakarta Indonesia

The increase in aircraft noise is an inevitable impact of Halim Perdanakusuma Airport (HLP) commercial operations since 2014. The perception of noise risk from people living around airports is a factor that must be considered for formulating strategic, comprehensive airport noise control plans and policies, and participatory. The purpose of this study is to analyze the noise conditions and the perception of environmental noise risk to the perception of socioeconomic risks that live around the HLP Airport. The results of the WECPNL calculation in area of Jaticempaka and Makasar was ranged between 73.80—79.72. The environmental noise risk of the community in HLP Airport's vicinity was studied from knowledge aspects, perception aspects, and behavior aspects. Most of respondent were in the moderate category of environmental noise risk knowledge and environmental noise risk perception. While for environmental noise risk behavior aspects most respondent were in the low category. The social and economic risk perception for most respondent were in the moderate category. The conclusion of this research is that the community settlements in HLP Airport's vicinity at the distance of 300 m and 600 m does not meet the environmental noise standard for a residential area which is regulated at 55 dB(A). The ideal area for settlement use in the vicinity of HLP Airport is Makassar area which is located 600 m from HLP Airport's runway.

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Development of Eco-Airport Model to Measure Environmental Noise Footprint in Supporting Airport Sustainability

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IOP Conference Series: Earth and Environmental Science 2021年第1期794卷

作者： Wahyu Sardjono Haryoto Kusnoputranto Tri Edhi Budhi Soesilo Gabriel A. Kristanto Information Systems Management Department BINUS Graduate Program - Master of Information Systems Management Bina Nusantara University Jakarta Indonesia 11480 Department of Environmental Health Faculty of Public Health University of Indonesia Indonesia Post Graduate Program School of Environmental Science University of Indonesia Jakarta Indonesia Environmental Engineering Department Faculty of Engineering University of Indonesia Jakarta Indonesia

Among a set of tools to emerge in recent years in environmental management, one appears to meet the criteria necessary to bridge this gap is the environmental footprint analysis based on biophysical reality of sustainable living, people must use natural renewable products and services not sooner than they are replacedand produces no waste faster than nature can absorb. The purpose of this study is to develop a model of noise environment footprint toward sustainability airport with the environmental assessment at Soekarno-Hatta International Airport. The results showed that the airport ecological footprint of the model can be built through the factors analysis that can give an idea of the influence of ecoairport. The conclusion of this study is to obtain the noise ecological footprint provides a method for the total impact of air transport to be assessed, the ecological footprint can be used as a communication and awareness tool to inform communities about the impact they make. It can lead to shifts to public transport for airport access, ecological footprint can be used by airports and airlines to identify operations where energy efficiency measures can be made and where resource consumption can be reduced

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System Dynamics Modeling for Petroleum Exploitation Using the 'Drifting Goals' Standard Model

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IOP Conference Series: Earth and Environmental Science 2021年第1期794卷

作者： Wahyu Sardjono Haryoto Kusnoputranto Tri Edhi Budhi Soesilo A. Kristanto information Systems Management Department BINUS Graduate Program - Master of Information Systems Management Bina Nusantara University Jakarta Indonesia 11480 Department of Environmental Health Faculty of Public Health University of Indonesia Indonesia Post Graduate Program School of Environmental Science University of Indonesia Jakarta Indonesia Environmental Engineering Department Faculty of Engineering University of Indonesia Jakarta Indonesia

In an oil drilling area, there are two oil drilling companies that have obtained permits to drill. As time goes by, the availability of existing petroleum decreases. To anticipate natural resources the government only prioritizes one company. Competition occurs between the two of them to explore petroleum from the ground so that they can drill. The purpose of this study is to provide an overview, how to make a system dynamics model related to the problem of oil drilling as an increasingly limited natural resource, by taking the case of the relationship between drilling companies in facing business competition. The method used is system dynamics with a standard model of mutual difficulties (drifting goals). The result obtained is a system dynamics model that can be used to demonstrate the behavior of a simulated petroleum drilling model to get an overview or condition of the limitations of petroleum and future availability.

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Ecological Footprint Model of Soekarno-Hatta International Airport from the Perspective of the Local Community

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IOP Conference Series: Earth and Environmental Science 2021年第1期794卷

作者： Wahyu Sardjono Haryoto Kusnoputranto Tri Edhi Budhi Soesilo Kristanto Gabriel A. Information Systems Management Department BINUS Graduate Program - Master of Information Systems Management Bina Nusantara University Jakarta Indonesia 11480 Department of Environmental Health Faculty of Public Health University of Indonesia Indonesia Post Graduate Program School of Environmental Science University of Infonesia Jakarta Indonesia Environmental Engineering Department Faculty of Engineering University of Indonesia Jakarta Indonesia

Soekarno-Hatta International Airport is prone to various environmental problems. The problem of population growth has an impact on increasing economic activity which directly impacts the environment. In every production activity from the environmental side, it will bring up the carrying capacity of the environment and the carrying capacity of the environment or ecological footprint. The problem will be difficult if it turns out that the ecological footprint that occurs exceeds the capacity of the existing environmental carrying capacity, also for airport problems. This will result in the airport being unsustainable. This article will discuss the model of the airport environmental footprint that is currently occurring at Soekarno-Hatta International Airport by utilizing the opinions of respondents who live and have activities around the airport. The factor analysis method is used to process the respondent's data to obtain the factors that influence the environmental footprint and then through these findings a model can be developed which is expected to be able to abstract the current conditions. The research results show that the dominant environmental footprint at Soekarno-Hatta airport is overload airport activities impact, operational slot time optimization, and renewable of airport energy, which can then be built as an instrument to evaluate, build and develop airport control policies that are environmentally friendly and sustainable.

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Design and implementation of synchronous rectification for an arc-welding machine

Design and implementation of synchronous rectification for a...

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Conference Record of the IEEE Industry Applications Society Annual Meeting (IAS)

作者： Flavio Marcos Coelho Michel Braz Cardoso Electrical Engineering Post-Graduate Program Federal University of Minas Gerais Belo Horizonte Brazil Federal University of Minas Gerais Belo Horizonte Brazil

In Arc-Welding Machines (AWM), the power-to-weight ration is an important project parameter. This paper brings a proposition to use synchronous rectification to lower rectification stage's power losses on semiconductors, increasing total efficiency. A commercial product was studied, tested and characterized and a synchronous rectifier was then designed to replace the passive diode rectifier. A model of the machine was created and verified by comparison with measured behaviour and then used to simulate the synchronous rectifier application. Simulation results showed a promising reduction in power losses, which could be used in reducing the machine's size or increasing its power rating. In both cases, an improvement of power-to-weight ratio is verified. Ultimately, bench tests and welding tests were made to establish a comparison point between the machine with passive rectifier and the machine with synchronous rectifier.

关键词： Welding Windings MOSFET Schottky diodes Topology Switches

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