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Utsev, J. T., et J. C. Agunwamba. « Modelling solar enhanced waste stabilization pond ». Water Practice and Technology 15, no 2 (11 mars 2020) : 282–94. http://dx.doi.org/10.2166/wpt.2020.014.
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Abstract Solar enhanced waste stabilization pond (SEWSP) was modeled in this research. In the analysis, SEWSPs of varying sizes, made of metallic tanks with inlet and outlet valves and solar reflectors, were constructed to increase the incident solar intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physico-chemical and biological characteristics for a period of twelve (12) months. The parameters examined were temperature, pH, detention time, total suspended solids, dissolved oxygen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), algae count, faecal coliforms and E. coli. The efficiencies of the SEWSPs with respect to these parameters fluctuated with depth, location of reflectors and variation in width. The SEWSP with a width of 0.2 m whose reflector was installed at the outlet position gave the highest treatment efficiency. The conventional model was modified to account for solar irradiation. The faecal bacteria removal was significantly higher in the enhanced pond than in the conventional pond at 0.10 level of significance. The verification of the conventional model gave a good correlation of r = 0.882 between the measured and calculated Ne/No with a low standard error of s = 0.010, while the irradiated pond gave a correlation and standard error of r = 0.959 and s = 0.012 respectively. The research revealed that with the incorporation of solar radiation in WSPs, a length/ width/depth ratio of 1:0.2:0.2 can be used in the design of SEWSPs for maximum treatment efficiency.
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Foo, Swee Wen, Darrien Yau Seng Mah et Bartholomew Emily Ayu. « Modelling rainwater harvesting for commercial buildings ». Water Practice and Technology 12, no 3 (1 août 2017) : 698–705. http://dx.doi.org/10.2166/wpt.2017.077.
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Commercial areas are generally fully paved and with more impervious land cover than residential areas. This paper demonstrates a wall-mounted rainwater harvesting system designed to deal with limited land space. An arrangement of three tanks in series was used on a commercial shop lot where flat roofs generate large amounts of runoff. The system is compact, and can be installed and fitted close to any wall, promoting the efficient use of space. Analytical procedures and computational fluid dynamic modelling were used to explore the system's potential. This rainwater harvesting system, with its three water storage tanks, works well, and is suitable for implementation and can be integrated into urban stormwater management.
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Zhou, Hong, Bin Zhu, Wenshan Hu, Zhiwei Liu et Xingran Gao. « Modelling and Practical Implementation of 2-Coil Wireless Power Transfer Systems ». Journal of Electrical and Computer Engineering 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/906537.
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Wireless power transfer (WPT) based on inductive coupling could be potentially applied in many practical applications. It has attracted a lot of research interests in the last few years. In this paper, the modelling, design, and implementation of a 2-coil WPT system are represented. The prototype system can be implemented using conventional power electronic devices such as MOSFETs with very low costs as it works in relative low frequency range (less than 1 MHz). In order to find out about the optimal working area for the WPT system, the circuit model based on the practical parameters from the prototype is built. The relationships between the exciting frequency, coupling, and output power are analyzed based on the circuit and magnetic principles. Apart from the theoretic study, the detailed implementation of the WPT prototype including the coil design, digital frequency generation, and high frequency power electronics is also introduced in this paper. Experiments are conducted to verify the effectiveness of the circuit analysis. By carefully tuning the circuit parameters, the prototype is able to deliver 20 W power through 2.2 meter distance with 20–30% efficiency.
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Rehman, Masood, Zuhairi Baharudin, Perumal Nallagownden et Badar Ul Islam. « Modelling and Efficiency-Analysis of Wireless Power Transfer using Magnetic Resonance Coupling ». Indonesian Journal of Electrical Engineering and Computer Science 6, no 3 (1 juin 2017) : 563. http://dx.doi.org/10.11591/ijeecs.v6.i3.pp563-571.
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<p>Wireless power transfer (WPT) system has got significant attention in recent years due to its applications in consumer electronics, medical implants and electric vehicles etc. WPT is a promising choice in situations, where the physical connectors can be unreliable and susceptible to failure. The efficiency of WPT system decreasing rapidly with increasing air-gap. Many circuit topologies have been employed to enhance the efficiency of the WPT system. This paper presents the modelling and performance analysis of resonant wireless power transfer (RWPT) system using series-parallel-mixed topology. The power transfer efficiency analysis of the model is investigated via circuit theory. S-parameters have been used for measuring power transfer efficiency. Transient analysis is performed to realize the behavior of voltage and current waveforms using advanced design system (ADS) software. The proposed model is tested with two amplitudes i.e. 100 V peak-to-peak and 110 V peak-to-peak at the same frequency of 365.1 kHz. The overall result shows that the series-parallel-mixed topology model has higher efficiency at low coupling factor (K) for both voltage amplitudes.</p>
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Kanda, Edwin K., Emmanuel C. Kipkorir et Job R. Kosgei. « Modelling of nitrates in River Nzoia using MIKE 11 ». Water Practice and Technology 12, no 1 (1 mars 2017) : 217–23. http://dx.doi.org/10.2166/wpt.2017.026.
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Eutrophication is a serious problem in Lake Victoria as a result of enrichment by nutrients transported by the rivers draining into it. River Nzoia is one of the main rivers draining into the lake. The main aim of this study was to simulate the level of nitrates using MIKE 11 and to establish relationship between nitrogen and phosphorus. The model was calibrated using water quality data for 2009 and validated with March 2013 data and then it was used to simulate nitrate concentration for the wet month of April 2013. The model performance was good with R2 values of between 0.87 and 0.98 and EF values of between 0.73 and 0.96. From the simulations, the effluent discharge from municipal and industrial wastewater ponds elevated the concentration of the nitrates in the river. Analysis of the concentrations of nitrates for wet and dry periods showed significant variations indicating significant contributions from the catchment through run-off. The relationship between total nitrogen and total phosphorus was analysed and found to have a strong positive correlation (r = 0.714, p < 0.05) indicating that both originate from similar sources or are influenced by the same factors such as agriculture.
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Allama, Oussama, Mohamed Hadi Habaebi, Sheroz Khan, Elfatih A. A. Elsheikh et F. M. Suliman. « Modelling and Control Design of a Non-Collaborative UAV Wireless Charging System ». Sensors 22, no 20 (17 octobre 2022) : 7897. http://dx.doi.org/10.3390/s22207897.
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This study proposes an analytical model of a WPT system with three orthogonal transmitter coils organised to produce a concentrated and controlled omnidirectional magnetic field suited for charging a moving, rotating load, providing maximal energy transfer without receiving end feedback. In order to create a realistic 3D WPT simulation system and a precise controller design, the mutual coupling values in terms of the receiver angular positions are modelled using the Ansys software. In using the established model of the 3DWPT system, an extremum seeking control (ESC) is used to maximize the power transfer utilizing the input power as an objective function assigned with specified parametric values defining the WPT model. The output power transmitted by the sending-end coils to a load of a moving UAV rotating in orbit is displayed. According to simulation results, when the receiver UAV speed is close to 2250 deg/s, the controller can accomplish a maximum power transfer of 2.6w in almost 1ms.
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Palani, Sundarambal, et Pavel Tkalich. « Water Quality Modelling in the East Johor and Singapore Straits ». Open Journal of Water Pollution and Treatment 2014, no 2 (30 septembre 2014) : 36–49. http://dx.doi.org/10.15764/wpt.2014.02005.
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Liu, Jun, Chang Wang, Xiaofeng Wang et Weimin Ge. « Frequency Splitting and Transmission Characteristics of MCR-WPT System Considering Non-Linearities of Compensation Capacitors ». Electronics 9, no 1 (11 janvier 2020) : 141. http://dx.doi.org/10.3390/electronics9010141.
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The frequency splitting phenomenon and transmission characteristics have been research hotspots in the field of magnetically coupled resonance wireless power transfer (MCR-WPT). In this paper, non-linear dynamics theory was innovatively introduced into the research, and non-linear coupled transmission dynamics modelling of the MCR-WPT system was established considering the non-linearities of the compensation capacitor. The mechanism of the frequency splitting phenomenon of the MCR-WPT system was revealed through systematic mathematical analyses based on the modelling. The analysis results showed that the system usually has dual natural frequencies which are low resonance frequency and high resonance frequency. Based on non-linear dynamics theory, the transmission characteristics of the system with different non-linear parameters were discussed comprehensively in relation to the modelling. The results of the numerical simulations and theoretical analyses showed that non-linear parameters can cause the jumping phenomena with the output responses, and the output responses in the vicinities of the lower resonance frequencies were extremely sensitive to changes in the coupling coefficient. According to analyses of the linear and non-linear systems, the energy transmissions performed in the vicinity of the high resonance frequency had a wider working frequency band and a better transmission stability under non-linear conditions.
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Raya, Raghavendra Kumar, et Rajiv Gupta. « Rural community water management through directional tunnelling : visual modelling of rainwater harvesting system ». Water Practice and Technology 15, no 3 (2 juillet 2020) : 734–47. http://dx.doi.org/10.2166/wpt.2020.060.
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Abstract Rainwater, a prominent source of water, needs to be properly harvested for better utilisation during water unavailable circumstances. Creating rainwater storage structures is an important aspect in the planning of water resources as it serves for future water usage and consumption. Advancements in rainwater storage structures are not happening on a large scale. Most of the structures are limited to individual household rainwater collection. Innovations and advanced technology applications must address rainwater storage functioning for a community. This research work proposes an innovative method called directional tunnelling for the activity of rainwater harvesting and its management for a small community in a rural area. Initially, rainwater is harvested in multiple individual household tanks, and later the excess of water from the corresponding tanks is subsequently collected in a community tank named as directional tunnel. All the details related to rural community water management have been discussed as well as highlighted by visual modelling using Building Information Modelling (BIM) tools. The current research work is intended on the rural aspect; therefore, the directional tunnel's practical execution and results are portrayed in a better manner through a case study at a village in Rajasthan, India.
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Currie, J., N. Wragg, C. Roberts, J. Tattersall et G. Leslie. « Transforming ‘value engineering’ from an art form into a science – process resilience modelling ». Water Practice and Technology 9, no 1 (1 mars 2014) : 104–14. http://dx.doi.org/10.2166/wpt.2014.012.
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The resilience of a treatment facility should be an important part of its design and operation throughout its service life to ensure it meets compliance and production expectations. This has traditionally been difficult to assess and quantify, and as a consequence its management has largely been ignored, or has been reduced to a function of how many treatment stages are provided with redundancy and/ or backup ‘stand-by’ facilities. Without proper resilience assessment there will always be a tendency to undertake ‘gold-plate’ engineering producing specifications much higher than the business need. This consequently leads to higher capital and operational expenditure over the life of a treatment asset. Value engineering then ends up an art form, where negotiating the line between risk and cost is often more to do with good luck than judgement. Resilience assessment makes value engineering a science rather than an art, as well as providing a critical means of influencing and assessing investment decisions and operational and maintenance planning to minimise the overall cost of compliance. Asset resilience assessment techniques have been developed in other industries over the last 15 years. Recently the authors have applied these tried and tested approaches to water and wastewater treatment assets.
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Buamah, R., K. Akodwaa-Boadi, M. Paintsil, E. K. Baah-Ennumh et A. A. Adjaottor. « Modelling the chlorine decay process in a distribution network using a pilot system ». Water Practice and Technology 9, no 4 (1 décembre 2014) : 534–50. http://dx.doi.org/10.2166/wpt.2014.060.
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Chlorine is one of the many disinfectants used to ensure bacteriological safety of drinking water. Usually residual chlorine is maintained within the distribution network to combat any probable re-contamination of the distributed water. This residual free chlorine, however, decays in water due to its reaction with the bulk water and the pipe material or deposits on the pipe walls. This study aimed at determining and modelling chlorine decay in the Kumasi water distribution network (KWDN) and determined locations where residual chlorine boosting is necessary. A double-jacketed batch reactor and a constructed pilot distribution system (PDS) were used to determine the bulk and wall decay coefficients. The PDS was run using aged PVC pipes (15–20 years), asbestos concrete pipes (40–50 years) and cast iron pipes (84 years) that have been in use in the KWDN. The SynerGEE® hydraulic model was used to identify the ‘zero chlorine’ points and predict top-up quantities. The bulk decay coefficient was found to be 0.053 h−1 within 8 hours at 26 °C and the residual chlorine decayed within the bulk fluid by 32–34% of its initial dose. Under the conditions tested, the cast iron pipes had the highest overall decay coefficients (K). Five locations within the network were identified as probable chlorine boosting points).
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Sochacki, Adam, Jakub Kubiatowicz, Joanna Surmacz-Górska et Joanna Ćwikła. « Plant-wide modelling and simulation using steady-state data : a case study of the Gliwice WWTP, Poland ». Water Practice and Technology 8, no 1 (1 mars 2013) : 142–50. http://dx.doi.org/10.2166/wpt.2013.015.
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In last decade the focal point of the activated sludge (AS) modelling shifted from a secondary-treatment to a plant-wide level. This new approach offers more possibilities, therefore demands more effort and expertise from a modeller. This paper presents a plant-wide approach to modelling and simulation of a full-scale AS wastewater treatment plant (WWTP). The construction and routine operational data of the full-scale Central WWTP in Gliwice (Poland) were used in this study to develop an integrated model of the water and sludge lines of the plant. The core of the plant model was the Activated Sludge Model No.1 (ASM1), which combined with sub-models of the other processes, was implemented in the WEST® Software version 3.7.6. The calibration strategy, verification and predictive capacity of the model are discussed. The calibrated model permitted acceptable accuracy of the simulation, yet limited data restrained its scope. Thus, the obtained mathematical description of the plant is a preliminary yet sound basis for a more versatile model. The model limitations and opportunities for its further applications and development are discussed.
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Kiss, Katalin, et Miklós Patziger. « Statistical analysis of fine resolution flow datasets helps characterizing flow behaviour in primary clarifiers : a decision support method ». Water Practice and Technology 16, no 2 (4 février 2021) : 420–35. http://dx.doi.org/10.2166/wpt.2021.006.
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Abstract In situ measurement campaigns of primary clarifiers are rarely implemented properly because of their cost, time, and energy demand. Hydrodynamic modelling possibilities for such reactors have been intensely examined recently, but on-site factors affecting flow characteristics (e.g. flow distributors) have not received sufficient attention. This paper describes the use of ANOVA in examining fine resolution flow datasets and the related decision support method for in situ measurement campaigns and subsequent modelling processes. The characteristics of the flow and the applicability of 2D and 3D methods to investigate hydrodynamic features are discussed through the example of a rectangular primary clarifier, also considering the reproducibility of measurements ranging from typical nominal flow rates to peak loads. Based on the data, recommendations are provided on the adequate sizing of a measurement campaign, potentially reduced to a single longitudinal section (2D measurement). According to our results, performing hydrodynamic measurements with a 2D-arrangement of measuring points is sufficient in the case of such clarifiers, also with regard to the design processes. When applying the described methods, the related efforts and costs may be reduced and estimated more easily. However, care should be taken when applying this method to determine the spacing of measuring points correctly.
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Hvala, Nadja, Darko Vrečko et Cirila Bordon. « Plant-wide modelling for assessment and optimization of upgraded full-scale wastewater treatment plant performance ». Water Practice and Technology 13, no 3 (1 septembre 2018) : 566–82. http://dx.doi.org/10.2166/wpt.2018.070.
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Abstract This paper presents the design of a plant-wide CNP (carbon-nitrogen-phosphorus) simulation model of a full-scale wastewater treatment plant, which will be upgraded for tertiary treatment to achieve compliance with effluent total nitrogen (TN) and total phosphorus (TP) limit values. The plant-wide model of the existing plant was first designed and extensively validated under long-term dynamic operation. The most crucial step was a precise characterization of input wastewater that was performed by extending the plant performance indicators both to a water line and sludge line and systematically estimating identifiable wastewater characterization parameters from plant-wide performance indicators, i.e. effluent concentrations, biogas and sludge production, and sludge composition. The thus constructed simulation model with standard activated sludge model (ASM2d) and anaerobic digestion model (MantisAD) overpredicted ortho-P and ammonia-N on the sludge line, indicating a need to integrate state-of-the-art physico-chemical minerals precipitation models to simulate plant-wide interactions more precisely. The upgraded plant with multimode anaerobic/anoxic/oxic configuration shows limited denitrification potential. Therefore, additional reject water treatment was evaluated to improve effluent TN and TP performance.
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Nyende-Byakika, Stephen, Julius M. Ndambuki et Gaddi Ngirane-Katashaya. « Modelling of pressurised water supply networks that may exhibit transient low pressure – open channel flow conditions ». Water Practice and Technology 8, no 3-4 (1 septembre 2013) : 503–14. http://dx.doi.org/10.2166/wpt.2013.054.
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On account of an ever increasing scarcity of potable water, ineffective water distribution networks (WDNs) and growing demand, several water distribution systems exhibit intermittent flow behaviour, either inevitably or under the deliberate action of operators, when they are expanded beyond their design capacities. This tendency is generally undesirable due to the fact that it leads to reduced service levels and consumer dissatisfaction. Moreover, due to inadequate system pressures and insufficient flows, the analysis of intermittent flow behaviour requires unconventional approaches, ultimately complicating network management. In this paper, a description is given, of tools that were developed to aid the analysis of WDNs during situations of low or non-existent pressures. Testing of the tools revealed that they could represent network behaviour fairly accurately.
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Mohammed, Hadi, Hoese Michel Tornyeviadzi et Razak Seidu. « Modelling the impact of water temperature, pipe, and hydraulic conditions on water quality in water distribution networks ». Water Practice and Technology 16, no 2 (20 janvier 2021) : 387–403. http://dx.doi.org/10.2166/wpt.2021.002.
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Abstract Identifying and controlling the drivers of change in the quality of water within distribution systems requires a comprehensive understanding of the individual and interactive effects of relevant factors. This article examines the impact of water temperature, pipe characteristics, and hydraulic conditions on the microbiological, physical, and chemical parameters of water quality in the distribution network using Bayesian Dirichlet process mixture of linear models and random forest method. The study was based on a database of the distribution network for the city of Ålesund in Norway and records of water quality data measured at seven different locations in the network from 2013 to 2019. In both modelling approaches applied, temperature was identified as the main factor that controls the microbiological stability of water in the network. From the minimum to the maximum values of temperature in the pipes (3.35 °C–11.14 °C respectively), the probabilities of occurrence of bacteria in water increased from 0.36 to 0.95. Temperature was also shown to be an important factor that affects the chemical parameters of water quality (pH, alkalinity and electrical conductivity). Among the input parameters included in this study, concentration of residual chlorine was shown to have the strongest growth-inhibiting effect on Total Bacteria in the pipes. The results further showed that changes in the hydraulic conditions in the pipes (residence time and flow) were among the most important determinants of the physical, chemical and microbiological quality of water in the distribution network. The random forest models assigned minimal importance to the pipe characteristics and conditions on changes in the water quality parameters. However, the Bayesian models revealed that these parameters have significant impact on the quality of water in the pipes.
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Nirmala Rani, C. « Photocatalytic degradation of caffeine in a slurry reactor with intermittent UV irradiation : optimization and response surface modelling ». Water Practice and Technology 17, no 1 (24 décembre 2021) : 517–28. http://dx.doi.org/10.2166/wpt.2021.130.
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Abstract This study focusses on the photocatalytic degradation of caffeine (CAF), a stimulating drug and environmental contaminant that poses a threat to humans and the environment. The effect of operating parameters such as CAF initial concentration (5–20 mg/L), catalyst dosage (0.1–0.9 g/L) and pH (3.0–9.0) were explored in detail. The experimental results showed the maximum CAF and chemical oxygen demand (COD) removals of 87.2% and 66.7% respectively. The optimized parameters were: CAF initial concentration – 5 mg/L, catalyst dosage – 0.5 g/L and pH – 7.2. The photocatalytic degradation of CAF followed pseudo-first order kinetics. The obtained experimental data were analysed with response surface methodology (RSM) using Design Expert Software.
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Bonhomme, C., et G. Petrucci. « The performance of semi-distributed modelling in urban drainage : the trade-off between hydrological measurements and geographical data ». Water Practice and Technology 8, no 3-4 (1 septembre 2013) : 479–86. http://dx.doi.org/10.2166/wpt.2013.050.
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Nowadays, high resolution geographical data are widely available for research and operational purposes. The inclusion of these data into hydrological models may suggest a direct and clear improvement of their performances. Different configurations and model structures, including an increasing quantity of geographical information, are tested using the widely used Stormwater Management Model 5 on a 2.5 km2 pilot catchment (located in Sucy en Brie, close to Paris, France). The Nash-Sutcliffe criterion is used to estimate the goodness of fit between model simulations and available measurements. If including some basic spatial information on landuse clearly improves the performance of the uncalibrated model, the increase in performance is less obvious if the user continues to refine geographical information on the catchment. Moreover, model predictions are comparable between a model calibrated with an efficient calibration procedure and a more physical approach including a fine spatial description and no calibration. Finally, the quality of data used for calibration and validation seems to be a key parameter to obtain a good fit between measurements and model predictions.
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Oppong, G., G. A. Montague, M. O'Brien, M. McEwan et E. B. Martin OBE FREng. « Towards advanced control for anaerobic digesters : volatile solids inferential sensor ». Water Practice and Technology 8, no 1 (1 mars 2013) : 7–17. http://dx.doi.org/10.2166/wpt.2013.002.
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The lack of instrumentation in anaerobic digestion processes is a key bottleneck as sensors and analysers are necessary to reduce uncertainty related to the initial conditions, kinetics and the input concentrations of the process. Without knowledge of the process conditions, the process is inevitably difficult to control. This paper looks into the potential for developing a soft sensor for volatile solids (VS), an important variable that is currently only monitored offline. A VS inferential sensor is developed using data from an industrial process and compared with the results from a simulation study where feed flow and biogas production rate are used for modelling VS.
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Ziersen, J., J. Clauson-Kaas et J. Rasmussen. « The role of Greater Copenhagen Utility in implementing the city's Cloudburst Management Plan ». Water Practice and Technology 12, no 2 (1 juin 2017) : 338–43. http://dx.doi.org/10.2166/wpt.2017.039.
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This paper describes Greater Copenhagen Utility's role in planning, coordinating and implementing Copenhagen's Climate Change Adaptation Plan and Cloudburst management strategy. Detailed hydraulic modelling of the seven catchments in the city resulted in the preparation of a cloudburst management plan with more than 350 interventions, at a budget of EUR 1.3 billion. Among the planned projects are designated cloudburst boulevards, retention spaces, green roads and cloudburst tunnels. The joint efforts in coordinating climate change adaptation with city planning and infrastructure implementation, are shown to be key to succeeding with the projects. Stakeholder involvement in preparing the cloudburst management strategy is important in identifying the optimal solutions.
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Rodríguez, R., B. González, J. García, A. Lázaro, B. Iñiguez et A. Hernández. « Large-Signal DG-MOSFET Modelling for RFID Rectification ». Advances in Condensed Matter Physics 2016 (2016) : 1–6. http://dx.doi.org/10.1155/2016/8017139.
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This paper analyses the undoped DG-MOSFETs capability for the operation of rectifiers for RFIDs and Wireless Power Transmission (WPT) at microwave frequencies. For this purpose, a large-signal compact model has been developed and implemented in Verilog-A. The model has been numerically validated with a device simulator (Sentaurus). It is found that the number of stages to achieve the optimal rectifier performance is inferior to that required with conventional MOSFETs. In addition, the DC output voltage could be incremented with the use of appropriate mid-gap metals for the gate, as TiN. Minor impact of short channel effects (SCEs) on rectification is also pointed out.
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McAlister, T., M. Stephens et A. Allen. « Aura, the city of colour – Australia's shining example of widescale integrated water cycle management ». Water Practice and Technology 12, no 3 (1 août 2017) : 737–44. http://dx.doi.org/10.2166/wpt.2017.078.
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Aura, the ‘City of Colour’, is a 48,000 person masterplanned community on Queensland's Sunshine Coast. Aura commenced construction in 2015 and will be developed over the next 25 years. Aura sets a benchmark in Australia regarding large scale urban water sustainability through the application of techniques such as rainwater capture and reuse, construction and operational stormwater treatment, water conservation, advanced sewer system designs and potentially a major stormwater harvesting and indirect potable reuse scheme. This paper outlines the journey taken in seeing Aura advance from ‘concept’ to ‘reality’, describes data collection undertaken and modelling tools applied and outlines activities being implemented at Aura to protect sensitive downstream environments and simultaneously deliver water cycle and project sustainability benefits.
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Manko, Roman, Mario Vukotić, Danilo Makuc, Danijel Vončina, Damijan Miljavec et Selma Čorović. « Modelling of the Electrically Excited Synchronous Machine with the Rotary Transformer Design Influence ». Energies 15, no 8 (13 avril 2022) : 2832. http://dx.doi.org/10.3390/en15082832.
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An electrically excited synchronous machine (EESM) is a promising alternative to the permanent magnets synchronous machines being used in the automotive industry. However, the main disadvantage of the EESM with the conventional excitation system with brushes is the presence of slip rings on the shaft, which need regular maintenance. A promising alternative to the conventional excitation system of the EESM is a wireless power transfer (WPT) system. In this paper, we focused on WPT excitation system based on the rotary transformers. First, the model of the EESM in the d-q reference frame with vector control system has been built (based on the parameters of the real machine) and analyzed using MATLAB/Simulink software. Second, the influence of the rotary transformer design parameters on the dynamic performance of the EESM has been investigated. Finally, different topologies of the rotary transformers found in the literature have been analyzed, modeled and compared using an analytical and numerical approach. Based on the obtained results, the most suitable electrical parameters (i.e., geometry parameters, supply frequency, magnetizing and leakage inductance, winding resistance and efficiency) of the rotary transformer have been identified and implemented into the d-q model of EESM.
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Dale, M., A. Hosking, E. Gill, E. Kendon, H. J. Fowler, S. Blenkinsop et S. Chan. « Understanding how changing rainfall may impact on urban drainage systems ; lessons from projects in the UK and USA ». Water Practice and Technology 13, no 3 (1 septembre 2018) : 654–61. http://dx.doi.org/10.2166/wpt.2018.069.
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Abstract Urban flooding and wet weather pollution are recognised as significant problems across the world, and changes in rainfall patterns arising as a consequence of climate change are likely to exacerbate these problems. This paper shares learning from a ground-breaking project led by CH2M for UK Water Industry Research and approaches used in other CH2M projects around the world. The UK project has explored the use of very high resolution (1.5 km) climate model output and climate analogues; other projects have used other methods to derive new design rainfall statistics commonly used in modelling wet weather collection systems for flooding and pollution investigations. Estimates of rainfall change have been used within collection system models to estimate the flooding and pollution impact of these changes. The methods applied in these projects can be replicated globally.
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Yevalla, Gah-Muti Salvanus, Biyong Bi Mback Emmanuel Blaise, Rodrigue Ebonji Seth, Étienne Totcha Beka et Tabod Charles Tabod. « Constructing a 3D geological model from geophysical data for groundwater modelling and management in the Kribi-Campo sedimentary sub-basin, Cameroon ». Water Practice and Technology 15, no 1 (16 janvier 2020) : 105–19. http://dx.doi.org/10.2166/wpt.2020.004.
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Abstract Groundwater resources along the coast of Cameroon (Kribi–Campo Sub-Basin) are under siege from point and non-point pollution sources, climate change, urbanization and infrastructure development. This situation is made worse by the absence of a water management and development strategy. Managing and monitoring the area's water resources requires an understanding of the groundwater systems, and thus a thorough understanding of the geology. In this study, a 3D geological model was built from electro-seismic data and the structure of the area's aquifer system developed. The aquifer system structure was transferred into Visual MODFLOW Flex and then used to develop a typical hydrogeological model, which will help the management and monitoring of the area's groundwater resources. As more geological data become available, the current model can be updated easily by editing and recomputing. This work is expected to have a positive impact quite quickly on the provision of potable water and on public health.
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Jewell, A., et C. Alepin. « A holistic approach to water supply network operation – using desalination to improve cost efficiency ». Water Practice and Technology 12, no 2 (1 juin 2017) : 295–304. http://dx.doi.org/10.2166/wpt.2017.038.
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Seqwater is one of Australia's largest water businesses, with one of the most geographically spread and diverse asset bases. This includes 37 water treatment plants (WTPs), more than 600 km of bulk water supply pipeline, and the Gold Coast Desalination Plant (GCDP) constructed as part of the South East Queensland Millennium Drought response. The production of desalinated water has a greater unit-volumetric cost than the treatment of surface water due to high production energy costs. This paper presents the holistic approach adopted by Seqwater to find a solution for supply contingency while undertaking necessary upgrades and maintenance at the Mudgeeraba WTP. Through a process of network modelling, system risk mapping and financial analysis, it was demonstrated that operating the GCDP for 18 days would provide the best value solution due to the operating costs being offset by bulk supply network operational efficiency improvements.
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Perera, E. D. P., Y. Iwami et K. Fukami. « Point and non-point source nutrient loading simulation for the Takasaki River Basin, Chiba–Japan ». Water Practice and Technology 10, no 2 (1 juin 2015) : 328–36. http://dx.doi.org/10.2166/wpt.2015.039.
Texte intégralRésumé :
Urbanization, agriculture, fertilization, livestock farming and unprecedented precipitations are presumed to cause augmented loadings of nitrogen (N) and phosphorus (P) to rivers and downstream reservoirs. At present, point source (PS) pollution in watersheds can easily be controlled, and it has been well-managed due to growing awareness and strict low enforcements. However, the control of pollutants from non-point sources (NPS) is still challenging and NPS have been identified as the main cause of water pollution and eutrophication in watersheds at present. Limitations in technical, human and financial resources impede efficient monitoring of those influents at watershed scale. At this end, process-based modelling approaches play an important role in analysis of nutrient loading effects quantitatively and qualitatively. Process-based water and energy processes (WEP) hydrological model with its updated version to couple nutrient loading through the implementation of N and P circulation processes was studied in this paper highlighting the application of the model to the Takasaki River, a tributary to the Inba-numa Lake basin, Chiba prefecture, Japan to understand the impacts of PS and NPS to the river water quality.
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Klepiszewski, K., S. Seiffert, M. Regneri et E. Henry. « Methods to accompany and evaluate planning of combined sewer overflow treatment concepts for complex sewer systems ». Water Practice and Technology 9, no 1 (1 mars 2014) : 1–8. http://dx.doi.org/10.2166/wpt.2014.001.
Texte intégralRésumé :
Simulation tools are in common use to evaluate combined sewer overflow (CSO) treatment concepts in complex sewer systems. However, the planning of CSO structures in a sewer system is a matter of local constraints, expert knowledge and trial and error. Common standards only provide general recommendations to plan CSO structures and work out management strategies. Additionally, modelling the emissions of complex sewer systems tends to result in comprehensive findings. Although, it is essential to understand local behaviour and interaction of CSO structures in a system to improve local and overall performance there is a lack of tools to illustrate comprehensive simulation results in a simple way. In this context the methods presented here are developed. These include clear illustrations of the as-is state in the catchment using Sankey diagrams to show relevant volume and pollutant flows. Furthermore, loading and treatment indicators are suggested to illustrate local loading conditions and treatment capabilities of CSO structures in relation to the overall system. Additional emission indicators provide information on local emissions and show interactions of CSO structures. The results indicate that the suggested methods contribute to an efficient evaluation of interactions and performances to improve treatment strategies in the planning phase.
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Hudson, M., et C. Arabatzoudis. « Meeting Melbourne's future demand for water using aquifer storage and recovery ». Water Practice and Technology 12, no 4 (1 décembre 2017) : 909–16. http://dx.doi.org/10.2166/wpt.2017.080.
Texte intégralRésumé :
Abstract Melbourne is one of the fastest growing cities in Australia. City West Water (CWW) has developed an Integrated Water Cycle Management (IWCM) Strategy which includes the development of aquifer storage and recovery (ASR) schemes to store recycled water and storm water to assist with meeting future growth, where these schemes can be demonstrated to be viable and cost effective. The investigation and delivery of ASR projects by CWW is being undertaken in accordance with Australian guidelines, which set out a staged process for developing a scheme involving the use of recycled water. Detailed investigations into the Tertiary sand aquifer, including drilling, test pumping, injection testing, and groundwater and hydrochemical modelling, were used to inform the assessment process. These investigations have confirmed the viability of ASR at the lead site (West Werribee) following a risk-based multi-stage approach with increasing levels of assessment and financial commitment. An ASR scheme has now been constructed at West Werribee with injection trials proposed at a second site. This paper describes the staged investigation process, the key outcomes to date of CWW's investigations, the opportunities that ASR could enable, and the challenges of implementing ASR at CWW.
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Gönczi, Gábor. « Unconventional methods for pressure loss reduction in standard pipe elements ». Water Practice and Technology 13, no 2 (1 juin 2018) : 355–61. http://dx.doi.org/10.2166/wpt.2018.030.
Texte intégralRésumé :
Abstract Reduction of pressure at pump houses are the most feasible and most advantageous as the pipe design method that is used, is more than 200 years old and is based up on 19th century production technology. My research focuses on a general approach on improving and reducing the pressure loss of these pipe elements with the help of non-conventional methods, thus resulting in a lower and more optimal energy usage of pump houses. The problematic zones are identified with the help of numerical modelling, geometry changes can be made and tested the same method. The geometrical changes aiming at pressure loss reduction follow non-conventional ideas, form hemodynamic and other biomechanics sources. Pipes in the pump houses are designed, for more than 50 years of operation. Even a small pressure loss reduction with this new method will mean large amount of energy saving in total. The results show that 15%–60% of pressure loss reduction is feasible, according to the complexity of the geometry. Pressure loss reduction will reduce energy consumption of water pumps which will result in a more efficient water works operation.
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Richards, Nathalie, et Claudia Gutierrez-Arellano. « Effects of community-based water management decisions at catchment scale, an interdisciplinary approach : the case of the Great Ruaha River Catchment, Tanzania ». Water Practice and Technology 17, no 2 (1 février 2022) : 598–611. http://dx.doi.org/10.2166/wpt.2022.010.
Texte intégralRésumé :
Abstract Water User Associations are community-based institutions that cover segments of rivers and are responsible for water management decisions. These are the result of institutional blueprints designed by the international community, widely adopted around the world. However, the implementation gaps between these generic institutional designs and the working on the ground are vast and require site-specific information to support water management decisions at the local scale. We used a hydrological modelling approach to assess how community-based decisions can maximize their outcomes and improve overall availability of water resources in the Great Ruaha River Catchment in Tanzania, a catchment that is under severe drought pressures and is of the utmost ecological, social, and political relevance at the national scale. We provide information to support decisions on when and where to focus conservation and management strategies by identifying the seasonal and spatial variability of water availability in the catchment. Our methods have the potential to be used in other catchments around the world. This study shows the importance of assessing the hydrological processes affecting the geographies of community-based institutions to identify priority areas of action.
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Oyerinde, Ganiyu Titilope, Agnide E. Lawin et Oluwafemi E. Adeyeri. « Multi-variate infilling of missing daily discharge data on the Niger basin ». Water Practice and Technology 16, no 3 (28 mai 2021) : 961–79. http://dx.doi.org/10.2166/wpt.2021.048.
Texte intégralRésumé :
Abstract The Niger basin has experienced historical drought episodes and floods in recent times. Reliable hydrological modelling has been hampered by missing values in daily river discharge data. We assessed the potential of using the Multivariate Imputation by Chained Equations (MICE) to estimate both continuous and discontinuous daily missing data across different spatial scales in the Niger basin. The study was conducted on 22 discharge stations that have missing data ranging from 2% to 70%. Four efficiency metrics were used to determine the effectiveness of MICE. The flow duration curves (FDC) of observed and filled data were compared to determine how MICE captured the discharge patterns. Mann-Kendall, Modified Mann-Kendall, Pettit and Sen's Slope were used to assess the complete discharge trends using the gap-filled data. Results shows that MICE near perfectly filled the missing discharge data with Nash-Sutcliffe Efficiency (NSE) range of 0.94–0.99 for the calibration (1992–1994) period. Good fits were obtained between FDC of observed and gap-filled data in all considered stations. All the catchments showed significantly increasing discharge trend since 1990s after gap filling. Consequently, the use of MICE in handling missing data challenges across spatial scales in the Niger basin was proposed.
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Gabarrell, X., T. Morales-Pinzón, J. Rieradevall, M. R. Rovira, G. Villalba, A. Josa, y. C. Martínez-Gasol, A. C. Dias et D. X. Martínez-Aceves. « Plugrisost : a model for design, economic cost and environmental analysis of rainwater harvesting in urban systems ». Water Practice and Technology 9, no 2 (1 juin 2014) : 243–55. http://dx.doi.org/10.2166/wpt.2014.028.
Texte intégralRésumé :
In the context of transition to sustainability, one of the main challenges facing societies today is the supply of water. By integrating different methodological tools and studies we developed the innovative software program Plugrisost® (rainwater, greys and sustainability), a simulation model, that facilitates the economic evaluation and the potential environmental impact of alternative water supplies (rainwater harvesting [RWH] and greywater systems) at different scales of urban planning. This modelling tool contributes to urban water planning for smart cities development. Plugrisost® analyses the optimal design variables, cost and environmental performance of RWH and greywater systems, using tap water production as a reference system for comparison. The use of economic and environmental indicators can make the optimal size of a rainwater tank more restrictive when it is compared to the results regarding the satisfaction of the demand for rainwater. Economic and environmental analysis can help avoid oversizing tanks for rainwater and thus obtain greater benefits. Plugrisost includes estimated cost and Global Warming Potential, as well as other life cycle impact indicators for this purpose. A case study analyzing the implementation of a RWH system in a single-family house in Aveiro, Portugal is included, showing the importance of rainwater availability and demand for the successful operation of simulated systems.
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Gönczi, Gábor. « Computational fluid dynamics aided optimisation of liquid state antiseptic injection to water networks ». Water Practice and Technology 9, no 3 (1 septembre 2014) : 362–69. http://dx.doi.org/10.2166/wpt.2014.038.
Texte intégralRésumé :
Waterworks mostly use chlorine as an antiseptic substance. It can be added in gaseous or liquid form. The simplest technique is to use gaseous injection but it carries the most risk as chlorine gas is highly toxic. Therefore, the current trend is to switch to the much safer hypo doser technology, whereby the hypo is injected into the water pipes with injector tubes, similarly to chlorination but the mixing of the antiseptic liquid is more problematic. Correct placement of the inlet and measurement points is indispensable. With the help of the computational fluid dynamic (CFD) simulation not only can the flow of the specific water pipe be modelled but also mixing of the antiseptic fluid can be modelled, thereby the measurement and inlet points can be installed at the optimal locations. In very short pipe sections with a limited amount of pipe length to achieve proper mixing the use of static mixers was suggested. Efficiency of the static mixers is variable and they increase the pressure loss on the specific water pipe section, which inflicts additional energy costs. With the help of CFD modelling, the fluid dynamic phenomena (vortices, backflows, etc.) on these pipe sections can be utilised to help mixing of the antiseptic substance meaning the use of static mixers can be avoided.
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Jinadasa, K. B. S. N., S. K. Weragoda, E. Valencia, S. T. V. Sim et W. J. Ng. « Community engagement and pollution mitigation at Kandy Lake, Sri Lanka ». Water Practice and Technology 14, no 1 (11 décembre 2018) : 55–61. http://dx.doi.org/10.2166/wpt.2018.109.
Texte intégralRésumé :
Abstract Kandy City is a UNESCO world heritage site. Being the second largest city in Sri Lanka and host to the annual Esala Perahara festival, it has a floating population two to three times its 120,000 permanent residents. Among the city's key landmarks is Kandy Lake, a culturally, environmentally, and economically significant ornamental lake. Nevertheless, inadequate urban development regulation has resulted in serious pollution of the lake. An integrated remedial measure was needed to improve the urban lake's water quality sustainably, for the Kandy community and their cultural heritage. A project was initiated by the University of Peradeniya (UOP), Sri Lanka, and the Nanyang Environment and Water Research Institute (NEWRI), Singapore. It started with modelling of Kandy Lake and community surveys, demonstrated implementation of wastewater management technologies (floating wetlands and an aerobic sequencing batch reactor (SBR)), and initiated community outreach with schools. The project also involved local authorities and government agencies in Kandy, and provided an informal cooperation platform. After project handover on July 10, 2014, further developments were observed in Kandy, including implementation of sewerage and centralised wastewater treatment, rehabilitation of Kandy Lake and the Mid-Canal, and integration of Kandy Lake into the city's development plan and regulations.
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Brocard, D., S. J. Gan, L. Y. Koh, T. W. Tan, W. I. Cox, T. Schellhase, L. L. Woo et al. « Deep tunnel sewerage system phase 2 – hydraulics ». Water Practice and Technology 14, no 2 (28 mars 2019) : 409–22. http://dx.doi.org/10.2166/wpt.2019.026.
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Abstract The Deep Tunnel Sewerage System (DTSS) is aimed at providing a robust and efficient means of catering to Singapore's used-water needs. DTSS2 is the second phase of this project, comprising an approximately 30-km long South Tunnel, a 10-km long Industrial Tunnel, 60-km of Link Sewers and a new Water Reclamation Plant integrated with a NEWater facility. In contrast with tunnels designed to store overflows in combined sewer systems, the DTSS tunnels convey used-water all the time from Singapore's separated system. This paper describes hydraulic analyses that were conducted during the feasibility study and preliminary design. The topics covered include hydraulic modelling of the entire system with the main goal of ensuring system resilience, air management to avoid odours at ground level, and isolation of tunnel section using gates for potential maintenance or repair. The resilience analyses concentrated on the system functionality in case of a failure, to ensure that used-water can be safely conveyed to a treatment plant. The air management system included several odour control facilities and air jumpers to avoid escape of odorous air from the system and the isolation gates requires detailed hydraulic analyses to cater to the high heads involved.
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Ravulapalli, Sujitha, et Ravindhranath Kunta. « Statistical analysis on the removal of malachite green dye using active carbons of Achyranthes aspera and Allamanda blanchetii plants ». Water Practice and Technology 14, no 4 (16 septembre 2019) : 808–24. http://dx.doi.org/10.2166/wpt.2019.064.
Texte intégralRésumé :
Abstract Activated carbons were prepared from the stem parts of Achyranthes aspera and Allamanda blanchetii plants and were investigated as adsorbents for the removal of malachite green dye from contaminated water. Various extraction conditions such as pH, initial concentration of dye, adsorbent dosage, temperature, agitation time and presence of co-ions were optimized for the maximum possible extraction of the dye. For analyzing the combined effect of these parameters on the removal efficiency of the adsorbents, statistical optimization modelling was adopted. The adsorbents developed were characterized and the adsorption abilities were observed to be 40.0 mg/g and 53.0 mg/g for the active carbons of Achyranthes aspera and Allamanda blanchetii plants respectively. The mechanism of adsorption was studied using various isotherm models and it was found that the Freundlich model describes well the adsorption process. Thermodynamic studies revealed the endothermic and spontaneous nature of physisorption. The kinetics of adsorption were well defined by the pseudo-second-order model. Desorption and regeneration studies of the spent adsorbents indicated that the percentage of extraction has not come down below 80.0% even after five regenerations for both the adsorbents. The validity of the methods developed are tested with real dye-polluted industrial effluent samples.
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Williams, Y., M. Basitere, S. K. O. Ntwampe, M. Ngongang, M. Njoya et E. Kaskote. « Application of response surface methodology to optimize the COD removal efficiency of an EGSB reactor treating poultry slaughterhouse wastewater ». Water Practice and Technology 14, no 3 (8 mai 2019) : 507–14. http://dx.doi.org/10.2166/wpt.2019.032.
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Abstract The poultry slaughterhouse industry consumes a large volume of potable water for bird processing and equipment cleaning, which culminates in the generation of high strength poultry slaughterhouse wastewater (PSW). The wastewater contains high concentrations of organic matter, suspended solids, nitrogen and nutrients. Most poultry slaughterhouses in South Africa (SA) discharge their wastewater into the municipal sewer system after primary treatment. Due to its high strength, PSW does not meet SA's industrial discharge standards. Discharge of untreated PSW to the environment raises environmental health concerns due to pollution of local rivers and fresh water sources, leading to odour generation and the spread of diseases. Thus, the development of a suitable wastewater treatment process for safe PSW discharge to the environment is a necessity. In this study, a biological PSW treatment process using an Expanded Granular Sludge Bed (EGSB) was evaluated. Response surface methodology coupled with central composite design was used to optimize the performance of the EGSB reactor. The dependant variable used for optimization was chemical oxygen demand (COD) removal as a function of two independent variables, hydraulic retention time (HRT) and organic loading rate (OLR). The interactions between HRT, OLR and COD removal were analysed, and a two factorial (2FI) regression was determined as suitable for COD removal modelling. The optimum COD removal of 93% was achieved at an OLR of 2 g-COD/L/d and HRT of 4.8 days. The model correlation coefficient (R2) of 0.980 indicates that it is a good fit and is suitable for predicting the EGSB's COD removal efficiency.
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Rehman, Masood, Zuhairi Baharudin, Perumal Nallagownden et Badar ul Islam. « Design and Analysis of Resonant Wireless Power Transfer System ». MATEC Web of Conferences 225 (2018) : 02020. http://dx.doi.org/10.1051/matecconf/201822502020.
Texte intégralRésumé :
In this paper, the modelling and analysis of resonant wireless power transfer (RWPT) system are carried out by using circuit theory. Equations of the efficiency and frequency are derived for basic series-series circuit topology and series-parallel-mixed circuit topology. The designed model uses the series-parallel-mixed topology. The model is tested for two different peak-to-peak voltage levels including 20 V and 40 V. The achieved efficiency at 20 V is 49.10% and at 40 V is 49.52% approximately. The modelling is performed by using advanced design system (ADS) high frequency design software. In addition, an overview of currently available wireless power transfer (WPT) technologies and the recent study on inductive wireless power transfer (IWPT) and resonant wireless power transfer (RWPT) systems is also presented.
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Zhao, Feiran, Caijun Zhong, Xiaoming Chen, Hai Lin et Zhaoyang Zhang. « Energy Efficiency of Massive MIMO Downlink WPT With Mixed-ADCs ». IEEE Communications Letters 23, no 12 (décembre 2019) : 2316–20. http://dx.doi.org/10.1109/lcomm.2019.2940010.
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Thompson, Michael, Ivan Zelich, Evan Watterson et Tom E. Baldock. « Wave Peel Tracking : A New Approach for Assessing Surf Amenity and Analysis of Breaking Waves ». Remote Sensing 13, no 17 (25 août 2021) : 3372. http://dx.doi.org/10.3390/rs13173372.
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The creation and protection of surfing breaks along populated coastlines have become a consideration for many councils and governments as surfing breaks are a major driver of tourism. To assess the surf amenity of surfing breaks, a quantitative and objective assessment method is required. A new wave peel tracking (WPT) method has been developed using a shore-based camera to assess surf amenity by measuring and quantifying potential surfing ride rate, length, duration, speed and direction on a wave-by-wave basis. The wave peel (or “curl” below the wave peak) is the optimal surfing region on a wave, and each wave peel track represents a surfable ride. Wave peel regions are identified, classified and tracked using traditional and machine learning-based computer vision techniques. The methodology is validated by comparing the rectified wave peel tracks with GPS-measured tracks from surfers in the wave peel regions. The WPT methodology is evaluated with data from a reef and adjacent natural beach at the Gold Coast, Australia. The reef produced longer ride lengths than the nearshore region and showed a consistent breaking location along the reef crest. Spatial maps of the wave peel tracks show the influence of tides on the wave breaking patterns and intensity. The WPT algorithm provides a robust, automated method for quantifying surf amenity to provide baseline data for surf break conservation. The methodology has potential uses to verify numerical modelling of surf breaks and to assess the impact of coastal development on surf breaks.
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Colussi, Jacopo, Roberto Re et Paolo Guglielmi. « Modelling and Design of a Coils Structure for 100 kW Three-Phase Inductive Power Transfer System ». Energies 15, no 14 (12 juillet 2022) : 5079. http://dx.doi.org/10.3390/en15145079.
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This paper presents the modeling, the design and verification of a three-phase coil structure for high-power Wireless-Power-Transfer (WPT) in automotive applications. The system, a Three-Polar-Pad (TPP), with complex mechanical geometry, is analytically modeled with an equivalent simplified structure. Thanks to this simplification, a numerical design is performed to minimize cross-coupling effects among different phases of the same side (receiver or transmitter) maximizing the linkage flux receiver-to-transmitter and then the power transferred. The analytical model is then verified in a Finite-Element-Analysis (FEA) environment. A final design, comprehensive of the shielding, is proposed matching the preliminary design constraints. Hence, the preliminary model is verified by testing a prototype using a three-phase Silicon Carbide (SiC) inverter at the transmitter side. The capability of the system is demonstrated by transferring 100 kW with more than 94% DC-to-DC efficiency over a 50 mm air gap in perfectly aligned conditions.
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Wei, Nasha, James Gu, Fengshou Gu, Zhi Chen, Guoxing Li, Tie Wang et Andrew Ball. « An Investigation into the Acoustic Emissions of Internal Combustion Engines with Modelling and Wavelet Package Analysis for Monitoring Lubrication Conditions ». Energies 12, no 4 (16 février 2019) : 640. http://dx.doi.org/10.3390/en12040640.
Texte intégralRésumé :
Online monitoring of the lubrication and friction conditions in internal combustion engines can provide valuable information and thereby enables optimal maintenance actions to be undertaken to ensure safe and efficient operations. Acoustic emission (AE) has attracted significant attention in condition monitoring due to its high sensitivity to light defects on sliding surfaces. However, limited understanding of the AE mechanisms in fluid-lubricated conjunctions, such as piston rings and cylinder liners, confines the development of AE-based lubrication monitoring techniques. Therefore, this study focuses on developing new AE models and effective AE signal process methods in order to achieve accurate online lubrication monitoring. Based on the existing AE model for asperity–asperity collision (AAC), a new model for fluid–asperity shearing (FAS)-induced AE is proposed that will explain AE responses from the tribological conjunction of the piston ring and cylinder. These two AE models can then jointly demonstrate AE responses from the lubrication conjunction of engine ring–liner. In particular, FAS allows the observable AE responses in the middle of engine strokes to be characterised in association with engine speeds and lubricant viscosity. However, these AE components are relatively weak and noisy compared to others, with movements such as valve taring, fuel injection and combustions. To accurately extract these weaker AE’s for lubricant monitoring, an optimised wavelet packet transform (WPT) analysis is applied to the raw AE data from a running engine. This results in four distinctive narrow band indicators to describe the AE amplitude in the middle of an engine power stroke. Experimental evaluation shows the linear increasing trend of AE indicator with engine speeds allows a full separation of two baseline engine lubricants (CD-10W30 and CD-15W40), previously unused over a wide range of speeds. Moreover, the used oil can also be diagnosed by using the nonlinear and unstable behaviours of the indicator at various speeds. This model has demonstrated the high performance of using AE signals processed with the optimised WPT spectrum in monitoring the lubrication conditions between the ring and liner in IC engines.
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Wang, Zhulin, Yiming Zhang, Xinghong He, Bo Luo et Ruikun Mai. « Research and Application of Capacitive Power Transfer System : A Review ». Electronics 11, no 7 (6 avril 2022) : 1158. http://dx.doi.org/10.3390/electronics11071158.
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Capacitive power transfer (CPT) uses an electric field as the transfer medium to achieve wireless power transfer (WPT). Benefitting from the low eddy current loss, simple system structure and strong plasticity of the coupling coupler, the CPT system has recently gained much attention. The CPT system has significantly improved transfer power, system efficiency, and transfer distance due to continuous research and discussion worldwide. This review briefly presents the basic working principle of the CPT system and summarizes the theoretical research in four aspects, including coupling coupler and high-frequency power converter. Following this, the review focuses on research in six key directions, including system modelling and efficiency optimization. The application of CPT technology in five fields, including medical devices and transportation, is also discussed. This review introduces the progress of CPT research in recent years, hoping to serve as a reference for researchers, to promote the further research and application of the CPT system.
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Wang, Chengmin, Guangji Li, Imran Ali, Hongchao Zhang, Han Tian et Jian Lu. « The Management of Energy Transformation through Laser Charging in WPT for 5G Application : Prediction Model of the In0.3Ga0.7As Solar Cell ». Wireless Communications and Mobile Computing 2022 (19 janvier 2022) : 1–8. http://dx.doi.org/10.1155/2022/5991154.
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5G is the latest-generation network that powers the IoT in pace with energy transformation essentially demanded during the modern world, especially the wireless form. Laser charging means laser beam irradiance of the solar cell panel to generate the photovoltaic power, and its way belongs to the WPT (Wireless Power Transfer). During the process, uncertain and ungovernable factors affect the energy transfer of efficiency. We have chosen the In0.3Ga0.7As material as the semiconductor of the PV (photovoltaic) panel to enhance its photoelectric conversion efficiency. Nevertheless, during the PV processing, nonlinearity elements impact the prediction modelling, making it extremely difficult. This paper proposes a new forecasting model based on SVM (Support Vector Machine) which is drawn from SLT (Statistical Learning Theory). Since the forecast belongs to classification issue essentially, the main idea of SVM is extending the SLT dimensions. We used the kernel function for realization. The PV is done under the different conditions (constant temperature, gradient temperature, or various laser power). The gathered data is processed by MATLAB and the 3rd software: LIBSVM. Without the parameter optimization, the prediction accuracy of classification is 80% (32/40) against 100% (40/40). Considering that the experiment data have small quantity, further make the over 650 data size samples which are calculated by the formula to verify the model. Through the effect of a few random factors, the result still remains 80% or higher. The research work has resulted in a solution of a fast and precise prediction model in laser charging solar cell panel. It also revealed the implicit relationship between the factors of the PV.
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Daqrouq, K., et A. Dobaie. « Wavelet Based Method for Congestive Heart Failure Recognition by Three Confirmation Functions ». Computational and Mathematical Methods in Medicine 2016 (2016) : 1–11. http://dx.doi.org/10.1155/2016/7359516.
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An investigation of the electrocardiogram (ECG) signals and arrhythmia characterization by wavelet energy is proposed. This study employs a wavelet based feature extraction method for congestive heart failure (CHF) obtained from the percentage energy (PE) of terminal wavelet packet transform (WPT) subsignals. In addition, the average framing percentage energy (AFE) technique is proposed, termed WAFE. A new classification method is introduced by three confirmation functions. The confirmation methods are based on three concepts: percentage root mean square difference error (PRD), logarithmic difference signal ratio (LDSR), and correlation coefficient (CC). The proposed method showed to be a potential effective discriminator in recognizing such clinical syndrome. ECG signals taken from MIT-BIH arrhythmia dataset and other databases are utilized to analyze different arrhythmias and normal ECGs. Several known methods were studied for comparison. The best recognition rate selection obtained was for WAFE. The recognition performance was accomplished as 92.60% accurate. The Receiver Operating Characteristic curve as a common tool for evaluating the diagnostic accuracy was illustrated, which indicated that the tests are reliable. The performance of the presented system was investigated in additive white Gaussian noise (AWGN) environment, where the recognition rate was 81.48% for 5 dB.
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Mykletun, Arnstein, Tarjei Widding-Havneraas, Ashmita Chaulagain, Ingvild Lyhmann, Ingvar Bjelland, Anne Halmøy, Felix Elwert et al. « Causal modelling of variation in clinical practice and long-term outcomes of ADHD using Norwegian registry data : the ADHD controversy project ». BMJ Open 11, no 1 (janvier 2021) : e041698. http://dx.doi.org/10.1136/bmjopen-2020-041698.
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IntroductionAttention-deficit/hyperactivity disorder (ADHD) is among the most common mental disorders in children and adolescents, and it is a strong risk factor for several adverse psychosocial outcomes over the lifespan. There are large between-country and within-country variations in diagnosis and medication rates. Due to ethical and practical considerations, a few studies have examined the effects of receiving a diagnosis, and there is a lack of research on effects of medication on long-term outcomes.Our project has four aims organised in four work packages: (WP1) To examine the prognosis of ADHD (with and without medication) compared with patients with other psychiatric diagnoses, patients in contact with public sector child and adolescent psychiatric outpatient clinics (without diagnosis) and the general population; (WP2) Examine within-country variation in ADHD diagnoses and medication rates by clinics’ catchment area; and(WP3) Identify causal effects of being diagnosed with ADHD and (WP4) ADHD medication on long-term outcomes.Method and analysisOur project links several nationwide Norwegian registries. The patient sample is all persons aged 5–18 years that were in contact with public sector child and adolescent psychiatric outpatient clinics in 2009–2011. Our comparative analysis of prognosis will be based on survival analysis and mixed-effects models. Our analysis of variation will apply mixed-effects models and generalised linear models. We have two identification strategies for the effect of being diagnosed with ADHD and of receiving medication on long-term outcomes. Both strategies rely on using preference-based instrumental variables, which in our project are based on provider preferences for ADHD diagnosis and medication.Ethics and disseminationThe project is approved by the Regional Ethics Committee, Norway (REC number 2017/2150/REC south-east D). All papers will be published in open-access journals and results will be presented in national and international conferences.Trial registration numbersISRCTN11573246 and ISRCTN11891971.
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Karim, Mohammad L., Antonio M. Bosnjak, James McLaughlin, Paul Crawford, David McEneaney et Omar J. Escalona. « Transcutaneous Pulsed RF Energy Transfer Mitigates Tissue Heating in High Power Demand Implanted Device Applications : In Vivo and In Silico Models Results ». Sensors 22, no 20 (13 octobre 2022) : 7775. http://dx.doi.org/10.3390/s22207775.
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This article presents the development of a power loss emulation (PLE) system device to study and find ways of mitigating skin tissue heating effects in transcutaneous energy transmission systems (TETS) for existing and next generation left ventricular assist devices (LVADs). Skin thermal profile measurements were made using the PLE system prototype and also separately with a TETS in a porcine model. Subsequent data analysis and separate computer modelling studies permit understanding of the contribution of tissue blood perfusion towards cooling of the subcutaneous tissue around the electromagnetic coupling area. A 2-channel PLE system prototype and a 2-channel TETS prototype were implemented for this study. The heating effects resulting from power transmission inefficiency were investigated under varying conditions of power delivery levels for an implanted device. In the part of the study using the PLE setup, the implanted heating element was placed subcutaneously 6–8 mm below the body surface of in vivo porcine model skin. Two operating modes of transmission coupling power losses were emulated: (a) conventional continuous transmission, and (b) using our proposed pulsed transmission waveform protocols. Experimental skin tissue thermal profiles were studied for various levels of LVAD power. The heating coefficient was estimated from the porcine model measurements (an in vivo living model and a euthanised cadaver model without blood circulation at the end of the experiment). An in silico model to support data interpretation provided reliable experimental and numerical methods for effective wireless transdermal LVAD energization advanced solutions. In the separate second part of the study conducted with a separate set of pigs, a two-channel inductively coupled RF driving system implemented wireless power transfer (WPT) to a resistive LVAD model (50 Ω) to explore continuous versus pulsed RF transmission modes. The RF-transmission pulse duration ranged from 30 ms to 480 ms, and the idle time (no-transmission) from 5 s to 120 s. The results revealed that blood perfusion plays an important cooling role in reducing thermal tissue damage from TETS applications. In addition, the results analysis of the in vivo, cadaver (R1Sp2) model, and in silico studies confirmed that the tissue heating effect was significantly lower in the living model versus the cadaver model due to the presence of blood perfusion cooling effects.
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Wigum, Børge Johannes, et Jan Lindgård. « Three decades of international RILEM activities to combat deleterious Alkali-Silica Reactions (ASR) in concrete. » MATEC Web of Conferences 199 (2018) : 03001. http://dx.doi.org/10.1051/matecconf/201819903001.
Texte intégralRésumé :
Since 1988, the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM) Technical Committees (TCs) have been seeking to establish universally applicable test methods for assessing the alkali-reactivity potential of aggregates, and from later on, for concrete mixes. TC 106 (1988 – 2001) focused on accelerated aggregate tests. The successor committee TC 191-ARP (2001 – 2006) also included work on diagnosis/appraisal & specification. TC 219-ACS (2006 – 2014) introduced work on performance testing & modelling. The major recommendations were published as a RILEM State-of-the-art Report in 2016. In 2014, TC 258-AAA was established, scheduling to finish the work on performance-based assessment in 2019. This current TC is focusing on the following Work Packages; WP1Performance based testing concepts, WP2 Relationship between results from laboratory and field and the establishment of field exposure sites, WP3 Testing of potential alkalis released from certain types of aggregates and measurement of internal concrete alkali content, and eventually; WP4 Verification of alkalis released from aggregates.
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Jankowski, T., et M. K. Koch. « Wet resuspension modelling and validation ». Kerntechnik 83, no 3 (18 juin 2018) : 227–31. http://dx.doi.org/10.3139/124.110869.
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