486 research outputs found

    Towards electric bus system: planning, operating and evaluating

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    The green transformation of public transportation is an indispensable way to achieve carbon neutrality. Governments and authorities are vigorously implementing electric bus procurement and charging infrastructure deployment programs. At this primary but urgent stage, how to reasonably plan the procurement of electric buses, how to arrange the operation of the heterogeneous fleet, and how to locate and scale the infrastructure are urgent issues to be solved. For a smooth transition to full electrification, this thesis aims to propose systematic guidance for the fleet and charging facilities, to ensure life-cycle efficiency and energy conservation from the planning to the operational phase.One of the most important issues in the operational phase is the charge scheduling for electric buses, a new issue that is not present in the conventional transit system. How to take into account the charging location and time duration in bus scheduling and not cause additional load peaks to the grid is the first issue being addressed. A charging schedule optimization model is constructed for opportunity charging with battery wear and charging costs as optimization objectives. Besides, the uncertainty in energy consumption poses new challenges to daily operations. This thesis further specifies the daily charging schedules with the consideration of energy consumption uncertainty while safeguarding the punctuality of bus services.In the context of e-mobility systems, battery sizing, charging station deployment, and bus scheduling emerge as crucial factors. Traditionally these elements have been approached and organized separately with battery sizing and charging facility deployment termed planning phase problems and bus scheduling belonging to operational phase issues. However, the integrated optimization of the three problems has advantages in terms of life-cycle costs and emissions. Therefore, a consolidated optimization model is proposed to collaboratively optimize the three problems and a life-cycle costs analysis framework is developed to examine the performance of the system from both economic and environmental aspects. To improve the attractiveness and utilization of electric public transportation resources, two new solutions have been proposed in terms of charging strategy (vehicle-to-vehicle charging) and operational efficiency (mixed-flow transport). Vehicle-to-vehicle charging allows energy to be continuously transmitted along the road, reducing reliance on the accessibility and deployment of charging facilities. Mixed flow transport mode balances the directional travel demands and facilities the parcel delivery while ensuring the punctuality and safety of passenger transport

    Assessment of Physical Activity in Adults with Progressive Muscle Disease

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    Introduction: Insufficient physical activity is a major threat to global health. Physical activity benefits peoples’ physical and mental health. The general population, including people living with disabilities and muscle wasting conditions, are recommended to avoid excessive sedentary time and engage in daily activity. Adults with progressive muscle disease experience barriers to physical activity participation, including muscle weakness, fatigue, physical deconditioning, impairment, activity limitations and participation restrictions (including societal and environmental factors), and fear of symptom exacerbation. More research is required to understand the inter-relationship between health and physical activity for adults with progressive muscle disease, particularly non-ambulant people who are under-represented in the existing research literature. Accurate measurement of FITT (frequency, intensity, time, and type of physical activity) is vital for high-quality physical activity assessment. The aim of this thesis was to assess the physical activity of ambulant and non-ambulant adults with progressive muscle disease.Systematic review findings identified various measures used to assess physical activity in adults with muscular dystrophy, including accelerometers, direct observation, heart rate monitors, calorimetry, positioning systems, activity diaries, single scales, interviews and questionnaires. None of the measures identified in the systematic review had well established measurement properties for adults with muscular dystrophy.Patient and public involvement interviews highlighted the importance of inclusive, remote, and technology-facilitated research design, the potential intrusion of direct observations of physical activity, the familiarity of questionnaires for data collection, and practical considerations to ensure wearing an activity monitor was not too burdensome.A feasibility study using multiple methods in 20 ambulant and non-ambulant adults with progressive muscle disease revealed satisfactory acceptability, interpretability, and usability of Fitbit and activity questionnaires, in both paper and electronic formats. During supervised activity tasks, Fitbit was found to have satisfactory criterion validity, reliability, and responsiveness and measurement properties were strengthened using multisensory measurement.An observational, longitudinal study that included 111 ambulant and non-ambulant adults with progressive muscle disease showed that:Activity monitoring had satisfactory validity, reliability and responsiveness using Fitbit, but there was considerable measurement error between Fitbit and the research grade GENEActiv accelerometer. Fitbit thresholds and multiple metrics (including accelerometer and heart rate data extrapolations of FITT) were appropriate for physical activity assessment in ambulant and non-ambulant adults with progressive muscle disease.Activity self-report had unsatisfactory concurrent validity, test-retest reliability, and responsiveness with substantial activity overestimation using the modified International Physical Activity Questionnaire. However, self-report properties were improved when used concurrently with Fitbit.Observed physical activity in adults with progressive muscle disease was generally low with excessive daily sedentary time. Activity frequencies, intensities and durations were lower, and activity types were more domestic, for wheelchair users and during the COVID-19 lockdown. Lower physical activity was significantly associated with greater functional impairment, less cardiorespiratory fitness, worse metabolic health, and lower quality of life. Activity optimisation thresholds and minimal clinically important differences were established.Discussion: The implications of this thesis include guidance for selection of appropriate physical activity measures by clinicians and researchers working with adults with progressive muscle disease. Fitbit is suitable in clinical practice and research for interactive, weekly remote activity monitoring or to support activity self-management and may represent an appropriate compromise between potential underestimation by accelerometry alone, and overestimation by self-report alone. A draft conceptual framework for physical activity measurement was also proposed. It includes frequency, intensity, time, and type of physical activity, and incorporates wider aspects of the physical activity construct, including somatic factors (relating to progressive muscle disease and underlying fitness) and contextual factors (relating to personal, social, and environmental situations). Future research will build on the knowledge gained in this thesis, furthering understanding of the inter-relationships between physical activity, health and wider contexts. Implementation will include testing a remote physical activity optimisation intervention that is inclusive of ambulant and non-ambulant participants, featuring Fitbit self-monitoring with a focus on optimisation of daily activity frequency and regularly interrupting sedentary time.</div

    An investigation of energy saving behaviour for residential buildings in Nigeria

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    Threats of climate change, global warming and uncertainty about future energy prices have sparked a global discussion about energy efficiency, particularly energy saving behaviour in residential buildings. Numerous challenges have been faced in achieving energy savings, with specific concern on energy consumption behaviour of building occupants. Accordingly, governments have set targets through policies for the reduction of energy emission, these have been adopted by the building industry through policies on energy efficiency in buildings including public private partnership in energy management and the development of near zero energy buildings.Previous studies have shown that occupant behaviour can result in a significant amount of variance in building energy use. To address these challenges in line with objectives of sustainable development goal (clean and sustainable energy and climate action), as well as energy efficiency in residential buildings, this research investigated key factors as well as practices that determine and limit energy saving behaviour in residential buildings from a different cultural perspective. Nigeria has been constantly confronted with an electricity demand that exceeded supply capacity. The increased demand for electricity can be attributed to growing populations, increased commercial activity and industrialisation. Households are a significant contributor to the rapidly increasing electricity demand as identified. Energy providers resort to ‘load shedding’ of electricity supply between communities and industries and even long-term electrical outage due to limited supply. It is also important to understand how the actions of occupants affect energy consumption behaviour in residential buildings. To reduce electricity demand and save energy, this research exploited literature on energy saving behaviour and behaviour change. The research study was conducted based on a sequential exploratory mixed method and consists of two key phases. Firstly, qualitative data was collected using semi-structure interview with eighteen experts in the energy and construction industry in Nigeria. The purpose of which was to provide an insight into residential energy consumption behaviour and the barriers faced in the adoption of sustainable energy sources. Analysis from the result shows that cost of energy is a major driver to the adoption of energy saving practices as there are no compulsory regulatory agencies to enforce and facilitate the migration to a more sustainable and innovative society. Furthermore, results also show that there is a need for continuous awareness on energy saving behavioural change, a need for government subsidies on renewable energy, government checks and standardization of energy efficient appliances imported into the country could improve the trust towards sustainable choices and promote efficient energy use. The second phase involved a household survey with 317 households from the case study area. The survey instrument was developed based on the constructs of energy culture framework, sociodemographic factors and physical environment. The hypothesised relationship from the conceptual model were tested using structural equation modelling (SEM). The results indicated that energy practices, material culture, attitude perception cognitive and social norms with behaviour changes were statistically significant, with attitude perception cognitive and social norms having the least impact on behaviour change. Additionally, the correlations from the constructs shows a direct relationship with behaviour change in achieving energy efficiency and energy saving approach while a deliberate policy to achieve energy efficiency and energy saving practices is vital to achieve sustainable development goals. The outcome from this work provided a better understanding of drivers and barriers to energy use behaviour and will inform future energy policy and interventions related to household energy saving. It also will contribute to the existing body of knowledge as well as give policy direction of governments towards climate action and some specific objectives of sustainable development goals

    Capacitive power transfer for maritime electrical charging applications

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    Wireless power transfer can provide the convenience of automatic charging while the ships or maritime vehicles are docking, mooring, or in a sailing maneuver. It can address the challenges facing conventional wired charging technologies, including long charging and queuing time, wear and tear of the physical contacts, handling cables and wires, and electric shock hazards. Capacitive power transfer (CPT) is one of the wireless charging technologies that has received attention in on-road electric vehicle charging applications. By the main of electric fields, CPT offers an inexpensive and light charging solution with good misalignment performance. Thus, this study investigates the CPT system in which air and water are the separation medium for the electrical wireless charging of small ships and unmanned maritime vehicles. Unlike on-road charging applications, air or water can be utilized as charging mediums to charge small ships and unmanned maritime vehicles. Because of the low permittivity of the air, the air-gapped capacitive coupling in the Pico Farad range requires a mega-hertz operating frequency to transfer power over a few hundred millimeters. This study examines an air-gapped CPT system to transfer about 135 W at a separation distance of 50 mm, a total efficiency of approximately 83.9%, and a 1 MHz operating efficiency. At 13.56 MHz, the study tested a shielded air-gapped CPT system that transfers about 100 W at a separation distance of 30 mm and a total efficiency of about 87%. The study also examines the underwater CPT system by submerging the couplers in water to increase the capacitive coupling. The system can transfer about 129 W at a separation distance of 300 mm, a total efficiency of aboutapproximately%, and a 1.1 MHz operating efficiency. These CPT systems can upscale to provide a few kW for small ships and unmanned maritime vehicles. But they are still facing several challenges that need further investigations

    Komponentenbasierte dynamische Modellierung von Energiesystemen und Energiemanagement-Strategien für ein intelligentes Stromnetz im Heimbereich

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    The motivation of this work is to present an energy cost reduction concept in a home area power network (HAPN) with intelligent generation and flexible load demands. This study endeavors to address the energy management system (EMS) and layout-design challenges faced by HAPN through a systematic design approach. The growing demand for electricity has become a significant burden on traditional power networks, prompting power engineers to seek ways to improve their efficiency. One such solution is to integrate dispersed generation sources, such as photovoltaic (PV) and storage systems, with an appropriate control mechanism at the distribution level. In recent years, there has been a significant increase in interest in the installation of PV-Battery systems, due to their potential to reduce carbon emissions and lower energy costs. This research proposes an optimal economic power dispatch strategy using Model Predictive Control (MPC) to enhance the overall performance of HAPN. A hybrid AC/DC microgrid concept is proposed to address the control choices made by the appliance scheduling and hybrid switching approaches based on a linear programming optimization framework. The suggested optimization criteria improve consumer satisfaction, minimize grid disconnections, and lower overall energy costs by deploying inexpensive clean energy generation and control. Various examples from actual case study demonstrate the use of the established EMS and design methodology.Die Motivation dieser Arbeit besteht darin, ein Konzept zur Senkung der Energiekosten in einem Heimnetzwerk (HAPN) mit intelligenter Erzeugung und exiblen Lastanforderungen vorzustellen. Im Rahmen dieser Forschungsarbeit wird ein Entwurf für ein HAPN entwickelt, indem das Energiemanagementsystem (EMS) und der Entwurf des Layouts auf der Grundlage des Systemmodells und der betrieblichen Anforderungen gelöst werden. Die steigende Nachfrage nach Elektrizität ist für traditionelle Stromnetze kostspielig und infrastrukturintensiv. Daher konzentrieren sich Energietechniker darauf, die Effizienz der derzeitigen Netze zu erhöhen. Dies kann durch die Integration verteilter Erzeugungsanlagen (z. B. Photovoltaik (PV), Speicher) mit einem geeigneten Kontrollmechanismus für das Energiemanagement auf der Verteilungsseite erreicht werden. Darüber hinaus hat das Interesse an der Installation von PV-Batterie-basierten Systemen aufgrund der Reduzierung der CO2-Emissionen und der Senkung der Energiekosten erheblich zugenommen. Es wird eine optimale wirtschaftliche Strategie für den Energieeinsatz unter Verwendung einer modellprädiktiven Steuerung (MPC) entwickelt. Es wird zudem ein hybrides AC/DC-Microgrid-Konzept vorgeschlagen, um die Steuerungsentscheidungen, die von den Ansätzen der Geräteplanung und der hybriden Umschaltung getroffen werden, auf der Grundlage eines linearen Programmierungsoptimierungsrahmens zu berücksichtigen. Die vorgeschlagenen Optimierungskriterien verbessern die Zufriedenheit der Verbraucher, minimieren Netzabschaltungen und senken die Gesamtenergiekosten durch den Einsatz von kostengünstiger und sauberer Energieerzeugung. Verschiedene Beispiele aus einer Fallstudie demonstrieren den Einsatz des entwickelten EMS und der Entwurfsmethodik

    The performance of high voltage; outdoor insulation in polluted environments

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    "An iron wire, 12000 feet in length, was suspended about five feet from the ground by silk cords; one end of it was connected to the globe of an electrical machine, and at the other a lead ball was hung in order to perceive when the matter reached it. After five or six turns of the wheel, the matter had passed along the whole wire and communicated its virtue to the ball, which instantly attracted and repelled light bodies. 2. As this ball was equally electrified with every part of the wire, it is probable that the electric matter would instantly pervade a wire of a still greater length, provided we had a proper apparatus for the purpose. 3. Several metals and other conductors were substituted in place of the ball, and all received the electricity in the same manner. The ball and touched with other non-conductors, :when' the finger, gave a luminous spark and as smart a shock as when the end of the wire next to 'the 'gTobe·vas touched. All these effects instantly ceased whenever .. any person not electrified touched any part of the wire and commenced again a few seconds after his hand was withdrawn. The same effects are produced, though with more difficultly, when hair or woollen ropes were substituted in place of the silk ones: But they were entirely stopped by hemp ropes or when the silk ones were wetted.

    Trends in electric vehicles research

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    Electrification of vehicles has been recognised as a key part of meeting global climate change targets and a key aspect of sustainable transport. Here, an integrative and bird\u27s-eye view of scholarly research on Electric Vehicles (EV) is provided with a focus on an objective and quantitative determination of research trends. The analyses suggest that areas of EV research linked to (i) charging infrastructure, (ii) EV adoption, (iii) thermal management systems and (iv) routing problem have been the distinct trending topics in recent years. While hybrid EV proves to have been a dominant keyword, its frequency of use has either flattened out in recent years or is notably on the decline across major subfields of EV research. The findings provide objective indications about the directions to which EV research is currently headed. A secondary outcome is the determination of references that have been most instrumental in developing each major stream of EV research

    Cyber-Human Systems, Space Technologies, and Threats

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    CYBER-HUMAN SYSTEMS, SPACE TECHNOLOGIES, AND THREATS is our eighth textbook in a series covering the world of UASs / CUAS/ UUVs / SPACE. Other textbooks in our series are Space Systems Emerging Technologies and Operations; Drone Delivery of CBNRECy – DEW Weapons: Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD); Disruptive Technologies with applications in Airline, Marine, Defense Industries; Unmanned Vehicle Systems & Operations On Air, Sea, Land; Counter Unmanned Aircraft Systems Technologies and Operations; Unmanned Aircraft Systems in the Cyber Domain: Protecting USA’s Advanced Air Assets, 2nd edition; and Unmanned Aircraft Systems (UAS) in the Cyber Domain Protecting USA’s Advanced Air Assets, 1st edition. Our previous seven titles have received considerable global recognition in the field. (Nichols & Carter, 2022) (Nichols, et al., 2021) (Nichols R. K., et al., 2020) (Nichols R. , et al., 2020) (Nichols R. , et al., 2019) (Nichols R. K., 2018) (Nichols R. K., et al., 2022)https://newprairiepress.org/ebooks/1052/thumbnail.jp
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