ARTICLE | doi:10.20944/preprints202203.0119.v1
Subject: Engineering, Automotive Engineering Keywords: smart scheduling; smart reservations; reinforcement learning; electric vehicle charging; electric vehicle charging management platform; neural network; DQN reinforcement Learning algorithm
Online: 8 March 2022 (08:54:48 CET)
The widespread adoption of electromobility constitutes one of the measures designed to reduce air pollution caused by traditional fossil fuels. However, several factors are currently impending this process, ranging from insufficient charging infrastructure, battery capacity, long queueing and charging time, to psychological factors. On top of range anxiety, the frustration of the EV drivers is further fueled by the lack the uncertainty of finding an available charging point on their route. To address this issue, we propose a solution that comes to bypass the limitations of the Reserve now function of the OCPP standard, enabling drivers to make charging reservations for the upcoming days, especially when planning a longer trip. We created an algorithm that generates reservation intervals based on the charging station's reservation and transaction history. Subsequently, we ran a series of test cases that yielded promising results, with no overlapping reservations.
ARTICLE | doi:10.20944/preprints202103.0592.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electric Vehicles; batch reinforcement learning; dueling neural networks; fitted Q-iteration
Online: 24 March 2021 (13:44:36 CET)
We consider the problem of coordinating the charging of an entire fleet of electric vehicles (EV), using a model-free approach, i.e. purely data-driven reinforcement learning (RL). The objective of the RL-based control is to optimize charging actions, while fulfilling all EV charging constraints (e.g. timely completion of the charging). In particular, we focus on batch-mode learning and adopt fitted Q-iteration (FQI). A core component in FQI is approximating the Q-function using a regression technique, from which the policy is derived. Recently, a dueling neural networks architecture was proposed and shown to lead to better policy evaluation in the presence of many similar-valued actions, as applied in a computer game context. The main research contributions of the current paper are that (i)we develop a dueling neural networks approach for the setting of joint coordination of an entire EV fleet, and (ii)we evaluate its performance and compare it to an all-knowing benchmark and an FQI approach using EXTRA trees regression technique, a popular approach currently discussed in EV related works. We present a case study where RL agents are trained with an epsilon-greedy approach for different objectives, (a)cost minimization, and (b)maximization of self-consumption of local renewable energy sources. Our results indicate that RL agents achieve significant cost reductions (70--80%) compared to a business-as-usual scenario without smart charging. Comparing the dueling neural networks regression to EXTRA trees indicates that for our case study's EV fleet parameters and training scenario, the EXTRA trees-based agents achieve higher performance in terms of both lower costs (or higher self-consumption) and stronger robustness, i.e. less variation among trained agents. This suggests that adopting dueling neural networks in this EV setting is not particularly beneficial as opposed to the Atari game context from where this idea originated.
ARTICLE | doi:10.20944/preprints201807.0625.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Electric vehicle charging station (EVCS), HOMER, MATLAB, CO2 emission, payback period
Online: 31 July 2018 (14:20:28 CEST)
The abrupt increase of the electric vehicles in Bangladesh needs huge amount of power. As a result, alternative energy sources are emphasized due to limited fossil fuels in order to develop a sustainable energy sector with environment friendly resources. Bangladesh has an enormous potential in the field of renewable resources like biogas and biomass. This paper presents 20 kW electric vehicle charging station (EVCS) utilizing biogas resources where maximum energy requirement is 100 kWh. In this paper, the biogas based EVCS is designed using MATLAB Simulink and HOMER software. Daily 15-20 electric vehicles can be recharged their batteries using the proposed charging station. The proposed system offers lower cost of energy compared to the grid electricity. Moreover, the proposed charging station shows 68.75% reduction in CO2 emission than grid based charging station. In addition, the proposed EVCS will save monthly $ 16.25 and $ 27.50 respectively for easy bike and auto rickshaw type electric vehicles in Bangladesh.
ARTICLE | doi:10.20944/preprints201806.0348.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: public sector; operating environment; electric bus; optimal charging type; charging infrastructure
Online: 22 June 2018 (06:13:55 CEST)
South Korea proposed reducing greenhouse gas emissions by 37% compared to the expected emissions by 2030 as the POST-2020 greenhouse gas reduction target. Electric vehicle distribution in the public sector is essential to achieve the carbon dioxide reduction target for transportation. In particular, when buses with internal combustion engines, which travel long distances and contribute substantially to greenhouse gas emissions, are replaced with electric buses, it is expected that greenhouse gas emissions will be significantly reduced. There are three types of electric buses with different power supply systems: a plug-in type in which power is supplied when a plug is inserted, a battery-swapping type in which a battery mounted on top of the vehicle is swapped at a swapping station, and a wireless type in which the battery is wirelessly charged through self-induction at a charging facility installed on the road. Vehicles of each charging type have different advantages and disadvantages. The performance, charging type, battery capacity, and operating environment of electric buses are mutually related parameters that must be considered when introducing such vehicles. Therefore, the optimal charging type must be selected according to the operating environment to enable the widespread use of electric buses. As such, this report proposes the optimal charging type according to the operating environment of public-sector electric vehicles.
ARTICLE | doi:10.20944/preprints202001.0224.v1
Subject: Engineering, Control & Systems Engineering Keywords: electric vehicles; sector coupling; energy system optimization; renewable energy integration; REMix; charging behavior; marginal values
Online: 20 January 2020 (10:08:13 CET)
Battery electric vehicles provide an opportunity to balance supply and demand in future power systems with high shares of fluctuating renewable energy. Compared to other storage systems such as pumped-storage hydroelectricity, electric vehicle energy demand is highly dependent on charging and connection choices of vehicle users. We present a model framework of a utility-based stock and flow model, a utility-based microsimulation of charging decisions, and an energy system model including respective interfaces to assess how the representation of battery electric vehicle charging affects energy system optimization results. We then apply the framework to a scenario study for controlled charging of nine million electric vehicles in Germany in 2030. Assuming a respective fleet power demand of 27 TWh, we analyze the difference between power-system-based and vehicle user-based charging decisions in two respective scenarios. Our results show that taking into account vehicle users’ charging and connection decisions significantly decreases the load shifting potential of controlled charging. The analysis of marginal values of equations and variables of the optimization problem yields valuable insights on the importance of specific constraints and optimization variables. In particular, state-of-charge assumptions and representing fast charging drive curtailment of renewable energy feed-in and required gas power plant flexibility. A detailed representation of fleet charge connection is less important. Peak load can be significantly reduced by 5% and 3% in both scenarios, respectively. Shifted load is very robust across sensitivity analyses while other model results such as curtailment are more sensitive to factors such as underlying data years. Analyzing the importance of increased BEV fleet battery availability for power systems with different weather and electricity demand characteristics should be further scrutinized.
ARTICLE | doi:10.20944/preprints202207.0445.v1
Subject: Social Sciences, Other Keywords: electric vehicles; public charging infrastructure; neighborhood charging; reservation system; urban; city; Hamburg
Online: 29 July 2022 (03:35:48 CEST)
Electric vehicles offer a means to reduce greenhouse gas emissions in passenger transport. The availability of reliable charging infrastructure is crucial for the successful uptake of electric vehicles in dense urban areas. In a pilot project in the city of Hamburg, Germany, public charging infrastructure is equipped with a reservation option providing exclusive access for local residents and businesses. The present paper combines quantitative and qualitative methods to investigate the effects of the newly introduced neighborhood charging concept. We use a methodology combining a quantitative questionnaire survey and qualitative focus group discussions as well as the analyses of charging infrastructure utilization data. Results show that inner-city charging and parking options are of key importance for (potential) users of electric vehicles. Hence, the neighborhood concept is rated very positively. Providing guaranteed charging and parking facilities are therefore likely to increase the stock of EVs. On the other hand, these could to a large extent be additional cars with consequential disadvantages. The study shows that openly accessible infrastructure is presently utilized much more intense than the exclusive option. Consequentially, the concept evaluated should be part of an integrated approach managing parking and supporting efficient concepts like car sharing.
ARTICLE | doi:10.20944/preprints202209.0174.v1
Subject: Engineering, Civil Engineering Keywords: open-source; photovoltaic; mechanical design; electric vehicle; solar energy; solar carport; electric vehicle charging station
Online: 13 September 2022 (10:41:43 CEST)
Solar powering the increasing fleet of electrical vehicles (EV) demands more surface area than may be available for photovoltaic (PV) powered buildings. Parking lot solar canopies can provide the needed area to charge EVs, but are substantially costlier than roof- or ground-mounted PV systems. To provide a lower-cost PV parking lot canopy to supply EV charging beneath them, this study provides a full mechanical and economic analysis on three novel PV canopy systems: (1) exclusively wood, single parking spot spanning system, (2) wood and aluminum double parking spot spanning system, and (3) wood and aluminum cantilevered system for curbside parking. All systems can be scalable to any amount of EV parking spots. The complete designs and bill of materials (BOM) of the canopies are provided along with basic instructions and are released with an open source license that will enable anyone to fabricate them. The results found single-span systems have cost savings of 82%-85%, double-span systems save 43%-50%, and cantilevered systems save 31%-40%. In the first operation year, the PV canopies can provide 157% of energy needed to charge the least efficient EV currently on the market if it is driven the average driving distance in London ON, Canada.
REVIEW | doi:10.20944/preprints201705.0090.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electric Vehicle; internal combustion engine; greenhouse gas; optimization techniques; Battery Electric Vehicle (BEV); Hybrid Electric Vehicle (HEV); Plug-in Hybrid Electric Vehicle (PHEV); Fuel Cell Electric Vehicle (FCEV).
Online: 10 May 2017 (17:44:51 CEST)
Electric vehicles (EV) are getting more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace the internal combustion engine (ICE) vehicles in near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system can face huge instabilities with enough EV penetration; but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of smart grid. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emission from the transportation sector. However, there are some major obstacles for EVs to overcome before replacing the ICE vehicles totally. This paper is focused on reviewing all the useful data available on EV configurations, energy sources, motors, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector.
REVIEW | doi:10.20944/preprints201909.0337.v1
Subject: Engineering, Automotive Engineering Keywords: fast-charging; electric vehicles; infrastructure; electrode materials; Li-ion batteries
Online: 30 September 2019 (03:29:10 CEST)
Electric vehicles (EVs) are being endorsed as the uppermost successor to fuel-powered cars, with timetables for banning the sale of petrol-fueled vehicles announced in many countries. However, the range and charging times of EVs are still considerable concerns. Fast charging could be a solution to consumers' range anxiety and the acceptance of EVs. Nevertheless, it is a complicated and systematized challenge to realize the fast charging of EVs because it includes the coordinated development of battery cells, including electrode materials, EV battery power systems, charging piles, electric grids, etc. This paper aims to serve as an analysis for the development of fast-charging technology, with a discussion of the current situation, constraints and development direction of EV fast-charging technologies from the macroscale and microscale perspectives of fast-charging challenges. It is emphasized that to essentially solve the problem of fast charging, the development of new battery materials, especially anode materials with improved lithium ion diffusion coefficients, is the key. It is highlighted that red phosphorus is the most promising anode that can simultaneously satisfy the double standards of high-energy density and fast-charging performance to a maximum degree.
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric vehicles charging navigation system; charging path; road transportation network; distribution network; real-time electricity price
Online: 30 November 2019 (09:39:27 CET)
Aiming at the current optimization problem of electric vehicle charging path planning, a charging path optimization strategy for electric vehicles under the "Traffic-Price-Distribution" mode is proposed. This strategy builds an electric vehicle charging and navigation system based on road traffic network model, real-time electricity price model and distribution network model. Based on Dijkstra shortest path algorithm and Monte Carlo time-space prediction method, the goal is to minimize the charging cost of electric vehicles. Optimal charging path. The simulation results of MATLAB and MATPOWER show that the electric vehicle charging path optimization strategy can better solve the local traffic congestion problem and improve the safety and stability of the distribution network on the basic of fully considering the convenience of electric vehicle charging.
ARTICLE | doi:10.20944/preprints201703.0107.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric vehicle (EV); charging station (CS); state of charge (SOC); structured query language (SQL); personal home page (PHP)
Online: 16 March 2017 (06:36:11 CET)
The enormous growth in the penetration of electric vehicles (EVs), has laid the path to advancements in the charging infrastructure. Connectivity between charging stations is an essential prerequisite for future EV adoption to alleviate users’ “range anxiety”. The existing charging stations fail to adopt power provision allocation and scheduling management. To improve the existing charging infrastructure data based on real-time information and availability of reserves at charging stations could be uploaded to the users to help them locate the nearest charging station for an EV. This research article focuses on an a interactive user application developed through SQL and PHP platform to allocate the charging slots based on estimated battery parameters, which uses data communication with charging stations to receive the slot availability information. The proposed server-based real-time forecast charging infrastructure avoids waiting times and its scheduling management efficiently prevents the EV from halting on road due to battery drain out. The proposed model is implemented using a low-cost microcontroller and the system etiquette tested.
Subject: Engineering, Electrical & Electronic Engineering Keywords: DC microgrid; electric vehicles; optimal sizing; station commitment
Online: 22 March 2019 (10:23:14 CET)
The diffusion of electric vehicles (EVs) can be sustained by the presence of integrated solutions offering parking and clean power supply. The recourse to DC systems allows to better integrate EV bidirectional energy exchange, photovoltaic panels and energy storage. In this paper, a methodology for optimal techno-economic sizing of a DC-microgrid for covering EV mobility needs is carried out. It is based on the definition of different scenarios of operation, according to typical EV usage outlooks and environmental conditions. In each scenario, optimal operation is carried out by means of a specific approach for EV commitment on different stations. The sizing procedure is able to handle the modular structure of microgrid devices. The proposed approach is applied to a case study of envisaged EV service fleet for Bari port authority.
ARTICLE | doi:10.20944/preprints201806.0316.v1
Subject: Engineering, Mechanical Engineering Keywords: electric vehicles; optimization; renewable energy charging station
Online: 20 June 2018 (08:58:05 CEST)
In recent years, integration of electric vehicles (EVs) has increased dramatically due to their lower carbon emissions and reduced fossil fuel dependency. However, charging EVs could have significant impacts on the electrical grid. One promising method for mitigating these impacts is the use of renewable energy systems. Renewable energy systems can also be useful for charging EVs where there is no local grid. This paper proposes a new strategy for designing a renewable energy charging station consisting of wind turbines, a photovoltaic system, and an energy storage system to avoid the use of diesel generators in remote communities. The objective function is considered to be the minimization of the total net present cost, including energy production, components setup, and financial viability. The proposed approach, using stochastic modeling, can also guarantee profitable operation of EVs and reasonable effects on renewable energy sizing, narrowing the gap between real-life daily operation patterns and the design stage. The proposed strategy should enhance the efficiency of conventional EV charging stations. The key point of this study is the efficient use of excess electricity. The infrastructure of the charging station is optimized and modeled.
ARTICLE | doi:10.20944/preprints201805.0299.v1
Subject: Engineering, Civil Engineering Keywords: site identification; electric charging infrastructure; electromobility; spatial analysis; modal split; public transport
Online: 22 May 2018 (10:49:04 CEST)
The spread of charging infrastructure (CIS) for battery electric vehicles is crucial for coping with the increasing number of electric vehicles. Therefore, the selection of ideal (fast-) charging locations determines acceptance, utilization and, thus, the economic viability of a single site or the whole charging network. The methodology of the Integrated Model Approach STELLA for site identification of CIS uses proven methods of traffic modeling such as the classic four-step traffic modeling in a new context to enable statements regarding the positioning of CIS. Based on different spatial analyzes and characterizations of urban quarters, traffic generated by individuals is calculated using the FGSV approach of 2010. Because only (electric) motorized individual traffic is of importance for CIS, the share of trips is calculated by differentiating the modal split between various transport groups. One approach is to concretize the modal split share of public transport based on analyzes of different criteria and data sets, e.g. the accessibility of stops. The model approach STELLA, which also combines various extensive data (e.g. transport networks and traffic volumes, settlement structures, vehicle characteristics, power supply data and user requirements), is currently developed for a planning area covering the entire territory of the Federal Republic of Germany.  STELLA is the acronym for the German term "STandortfindungsmodell für ELektrische LAdeinfrastruktur”.
ARTICLE | doi:10.20944/preprints202109.0222.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: efficiency; electric vehicle; finite element analysis; inductive charger; optimization
Online: 13 September 2021 (15:57:55 CEST)
Energy efficiency and leakage magnetic field (LMF) are two important issues in electric vehicle inductive chargers. In this work, the maximum achievable coil efficiency and the corresponding LMF strength are formulated as functions of hardware parameters, and figure of merits (FOM) are proposed for assessing the efficiency and LMF performance of the coil assembly pair. The impacts of the coil assemblies’ geometric parameters on both FOMs are examined with the aid of finite element analysis (FEA), and measures to improve the FOMs are extracted from FEA results. A coil assembly pair is manually optimized within given dimensional limits. Compared with the initial design, the optimized one achieves higher efficiency and lower LMF strength while consuming less copper. The performance improvement is verified by FEA results and experimental data measured on an 85 kHz electric vehicle inductive charger prototype. The key measures for coil assembly optimization are summarized.
ARTICLE | doi:10.20944/preprints202011.0452.v1
Subject: Engineering, Automotive Engineering Keywords: IPMSM; compressor; V-shaped PM; electric vehicle; Air conditioner
Online: 17 November 2020 (14:05:17 CET)
Air conditioning system of electric vehicles has new change as the internal combustion engine is being replaced with electrified AC motor. With large amount of batteries installed at the bottom of frame, the conventional compressor which is belt-driven can be removed and another AC motor can play the role for air conditioning in electric vehicles. From this change, the system efficiency would be improved since it is possible to control the electrified compressor independently from traction system in contrast with the belt-driven compressor. As a result, by applying the electrified compressor for air conditioning system, the whole system can achieve better efficiency and longer driving distance, which is most important in electric vehicles. In this paper, 3-phase interior permanent magnet synchronous motor (IPMSM) was designed using lumped-parameter model and finite element method.
ARTICLE | doi:10.20944/preprints202110.0245.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Electric Vehicle; Power Grid; Carbon Reduction Benefit; Multi-objective Optimization Model
Online: 18 October 2021 (13:12:29 CEST)
Under the goal of carbon peak and carbon neutrality, the carbon emission reduction of the automobile industry has attracted more and more attention in recent years. Electric vehicle has the dual attributes of power load and energy storage unit. With the increase of the number of electric vehicles, reducing carbon emissions through the collaborative interaction between electric vehicle and power network will become an important way to control carbon emissions in the automotive field. In this study, an optimization model of emission reduction benefits based on integrated development of electric vehicle and power grid is proposed, which explores the best technical way of synergy between power grid and electric vehicle, achieves the best carbon reduction effect and provides a model basis for large-scale demonstration application. Numerical simulations based on the real case in Beijing are conducted to validate the effectiveness of the proposed method.
ARTICLE | doi:10.20944/preprints202110.0377.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Lake Victoria; Photovoltaic; off-grid; model; electric two-wheeled vehicle; Wa-ter-Energy Hub; CARNOT
Online: 26 October 2021 (12:05:07 CEST)
Two-wheeler vehicles are the most significant mode of transportation for Kenyans in both rural and urban regions thereby contributing to local air pollution, and greenhouse gas emissions (GHG). The transition to electric two-wheeler vehicles can make a significant contribution to reducing GHG and improving the socio-economic lives of people living in rural Kenya. Re-newable energy systems can considerably contribute to the charging of electric two-wheeled vehicles, thus leading to the reduction of carbon emissions and the expansion of renewable energy penetration in rural Kenya. Therefore, this paper focuses on integrating and modelling electric two-wheeled vehicles (e-bikes) into an off-grid photovoltaic Water-Energy Hub located in the Lake Victoria Region of Western Kenya using the Conventional and Renewable Energy Opti-mization (CARNOT) Toolbox in MATLAB / Simulink. Electricity demand data obtained from the Water-Energy Hub was investigated and analysed. Potential solar energy surplus was identified and electric two-wheeler vehicles were integrated based on the surplus. A field measurement investigation on the energy consumption of the electric two-wheeler vehicles based on the rider’s driving behaviour was also carried. The annual electricity demand of 27,267 kWh, photovoltaic (PV) electricity production of 37,785 kWh with an electricity deficit of 370 kWh were obtained from the simulation results. To reduce the electricity deficit, a load optimisation algorithm was de-veloped to optimally integrate the electric 2-wheeler vehicle into the Water-Energy Hub. It was found that using the load optimisation algorithm, the annual electricity deficit was reduced to 1 kWh and the annual electricity demand was increased by 11% (30,767 kWh) which is enough to charge 4 additional electric two-wheeler batteries daily.
REVIEW | doi:10.20944/preprints202107.0164.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric vehicles; machine learning; Kalman filter; thermal modelling; online prediction; electromagnetic impedance spectroscopy; computational cost
Online: 6 July 2021 (17:34:49 CEST)
Highly nonlinear characteristics of lithium-ion batteries (LIBs) are significantly influenced by the external and internal temperature of the LIB cell. Moreover, cell temperature beyond the manufacturer’s specified safe operating limit could lead to thermal runaway and even fire hazards and safety concerns to operating personnel. Therefore, accurate information of cell internal and surface temperature of LIB is highly crucial for effective thermal management and proper operation of a battery management system (BMS). Accurate temperature information is also essential to BMS for the accurate estimation of various important states of LIB such as state of charge, state of health and so on. High capacity LIB pack, used in electric vehicles and grid-tied stationary energy storage system essentially consists of thousands of individual LIB cells. Therefore, installing a physical sensor at each cell especially at the cell core is not practically feasible from the solution cost, space and weight point of view. A solution is to develop a suitable estimation strategy which led scholars to propose different temperature estimation schemes aiming to establish a balance among accuracy, adaptability, modelling complexity and computational cost. This article presented an exhaustive review of these estimation strategies covering recent developments, current issues, major challenges, and future research recommendations. The prime intention is to provide a detailed guideline to the researchers and industries towards developing a highly accurate, intelligent, adaptive, easy to implement and compute efficient online temperature estimation strategy applicable to health-conscious fast charging and smart onboard BMS.
ARTICLE | doi:10.20944/preprints201612.0029.v1
Subject: Engineering, Automotive Engineering Keywords: electric vehicle; battery heat generation; battery degradation; vehicle operation cost; preheating target temperature; heating system
Online: 6 December 2016 (07:46:46 CET)
This paper presents an optimized energy management strategy for Li-ion power batteries used on electric vehicles (EVs) at low temperatures. Under low-temperature environments, EVs suffer a sharp driving range loss resulted from the energy and power capability reduction of the battery. Simultaneously, because of Li plating, battery degradation becomes an increasing concern as temperature drops. All these factors could greatly increase the total vehicle operation cost. Prior to battery charging and vehicle operating, preheating battery to a battery-friendly temperature is an approach to promote energy utilization and reduce total cost. Based on the proposed LiFePO4 battery model, the total vehicle operation cost under certain driving cycles is quantified in the present paper. Then given a certain ambient temperature, a target temperature of preheating is optimized under the principle of minimizing total cost. As for the preheating method, a liquid heating system is also implemented on an electric bus. Simulation results show that the preheating process becomes increasingly necessary with a decreasing ambient temperature; however, the preheating demand declines as driving range grows. Vehicle tests verify that the preheating management strategy proposed in this paper is able to save total vehicle operation cost.
ARTICLE | doi:10.20944/preprints202007.0691.v1
Subject: Engineering, Other Keywords: Electric bus; bus network; simulation; scheduling; charging infrastructure; depot charging; opportunity charging; optimisation; genetic algorithm; TCO
Online: 29 July 2020 (10:38:58 CEST)
Bus operators around the world are facing the transformation of their fleets from fossil-fuelled to electric buses. Two technologies prevail: Depot charging and opportunity charging at terminal stops. Total cost of ownership (TCO) is an important metric for the decision between the two technologies, however, most TCO studies for electric bus systems rely on generalised route data and simplifying assumptions that may not reflect local conditions. In particular, the need to re-schedule vehicle operations to satisfy electric buses’ range and charging time constraints is commonly disregarded. We present a simulation tool based on discrete-event simulation to determine the vehicle, charging infrastructure, energy and staff demand required to electrify real-world bus networks. These results are then passed to a TCO model. A greedy scheduling algorithm is developed to plan vehicle schedules suitable for electric buses. Scheduling and simulation are coupled with a genetic algorithm to determine cost-optimised charging locations for opportunity charging. A case study is carried out in which we analyse the electrification of a metropolitan bus network consisting of 39 lines with 4748 passenger trips per day. The results generally favour opportunity charging over depot charging in terms of TCO, however, under some circumstances, the technologies are on par. This emphasises the need for detailed analysis of the local bus network in order to make an informed procurement decision.
ARTICLE | doi:10.20944/preprints201709.0103.v1
Subject: Engineering, Automotive Engineering Keywords: in-wheel-motor electric vehicle; ride comfort; improved particle swarm optimization; linear quadratic regulator; fuzzy PID control
Online: 21 September 2017 (12:59:33 CEST)
In this paper, an in-wheel vibration absorber for In-wheel-motor electric vehicle (IWM EV) is designed, and a comprehensive control strategy of in-wheel absorber and vehicle suspension is proposed to improve vehicle ride comfort. The proposed in-wheel vibration absorber, designed for suppressing the motor vibration, is composed of a spring and a controllable damper. The values of in-wheel spring stiffness and damper initial coefficient are determined by using the improved particle swarm optimization (IPSO) algorithm, which is carried on the typical driving condition. To deal with the negative interaction effects between vehicle suspension and in-wheel absorber, the linear quadratic regulator (LQR) algorithm is utilized to control suspension damper, and the fuzzy PID method is utilized to control in-wheel damper. Based on the four evaluation indexes including vehicle body vertical acceleration, suspension dynamic deflection, wheel dynamic load and motor wallop, the simulation results show that, the proposed LQR control of suspension effectively improves vehicle ride comfort, and the fuzzy PID control of in-wheel damper exhibits superior performance of motor vibration suppressing in comparison to conventional electric wheel.
ARTICLE | doi:10.20944/preprints202007.0673.v1
Subject: Engineering, Automotive Engineering Keywords: life cycle assessment; agent-based traffic simulation; battery electric vehicles; sustainability; urban transportation; urban mobility; environmental engineering
Online: 28 July 2020 (10:13:30 CEST)
The transport sector in Germany causes one-quarter of energy-related greenhouse gas emissions. One potential solution to reduce these emissions is the use of battery electric vehicles. Although a number of life cycle assessments have been conducted for these vehicles, the influence of a transport system wide transition has not been researched sufficiently. Therefore, we developed a method which combines life cycle assessment with an agent-based transport simulation and synthetic electric, diesel and gasoline powered vehicle models. We use the transport simulation to obtain the number of vehicles, their lifetime mileage and road-specific consumption. Subsequently we analyze the product systems’ vehicle production, use phase and End-of-Life. The results are scaled depending on the covered distance, the vehicle weight and the consumption for the whole life cycle. The results indicate that the sole transition of drive trains is insufficient to significantly lower the greenhouse gas emissions. However, sensitivity analyses demonstrate that there is a considerable potential to reduce greenhouse gas emissions with higher shares of renewable energies, a different vehicle distribution and a higher lifetime mileage. The method facilitates the assessment of the ecological impacts of the complete car based transportation in urban agglomerations and is able to analyze different transport sectors.
ARTICLE | doi:10.20944/preprints202107.0037.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric mobility; electric vehicle; electrification; airport
Online: 1 July 2021 (22:00:53 CEST)
Following electrification of automotive transport, studies on the penetration of Electric Vehicles (EVs) are widespread, especially in defined contexts, e.g. cities. As major transport hubs, airports fall within contexts worth of interest. In this work, a forecast of the demand for electric mobility in an Italian international airport (Rome, Fiumicino) is presented. First, a wide review of proposed sce-narios on the penetration of EVs at international and national level and available data on local automotive transport are presented, as preliminary study for the definition of reference scenarios for the local context. Then the methodology proposed is presented and applied to the specific case study. Finally, a preliminary sizing of the required charging infrastructure is reported. The proposed approach can be considered as reference for similar studies on electrical mobility in other airport areas around the world.
REVIEW | doi:10.20944/preprints202010.0454.v1
Subject: Engineering, Automotive Engineering Keywords: Review; Electric Field; Ionic wind; Electric assisted combustion; Soot emission
Online: 22 October 2020 (09:54:38 CEST)
Electric field assisted combustion is an important means to improve fuel combustion efficiency. This paper conducts extensive research on flame characteristics under different forms and different application methods of electric fields, emission of soot particles and simulation status. Different flame parameter measurement methods will lead to different degrees of error, and perfect numerical simulation can make simple predictions on experimental data. Most of the current numerical simulations are in two dimensions, and it is necessary to develop a complete and accurate three-dimensional model to simulate and predict the characteristics of the flame under an electric field. The emission of soot particles is also affected by the electric field, and reasonable electric field parameters can greatly reduce the emission of soot particles. It is recommended to conduct centralized measurement of different fuels under the electric field under high pressure and temperature conditions, so as to be able to develop a wider and more accurate flame dynamics and chemical model under the electric field.
ARTICLE | doi:10.20944/preprints201809.0068.v1
Subject: Keywords: olfaction, olfactory, odorants, pheromones, smell, electric field, electromagnetic radiation, electric field sensor, insect antennae
Online: 4 September 2018 (14:31:22 CEST)
The olfactory system is capable of distinguishing individual odorants from among a virtually unlimited number. Fish, for example, detect changes in the electric field environment induced by prey and other sources. Floral electric fields exhibit variations in pattern and structure, which can be discriminated by bumblebees. We have constructed an electric field sensor, which, in the course of focussing on achieving maximum sensitivity and consistency, ultimately resembles features of the insect sensorium. A “fingerprint” 3D plot ( time, frequency range, voltage amplitude), representing the emitted electric field profile, is presented for each of a variety of odorants and other chemicals. The substance-specific electric-field emission and identification is not impeded by containers or barriers or distance.
REVIEW | doi:10.20944/preprints202109.0094.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Review; Electrical Machines; Superconducting Machines; Hybrid-Electric Aircraft; Propulsion Design; All-Electric Aircraft; Specific Power
Online: 6 September 2021 (13:04:15 CEST)
The development of electric aircrafts is becoming an important technology for achieving the goals set by the European Commission for the reduction of gases emissions by 2050 in the aeronautical transportation system. However, there is a gap between the values of specific power in commercial electric machines and the ones required for aeronautical applications. Therefore, the search for alternative materials and non-conventional designs is mandatory. One emergent solution is using superconducting machines and systems to overcome the current limits of conventional electrical machines. This work reviews the new hybrid and all-electric aircraft tendencies, complementing it with recent research on the design and development of high specific power superconducting machines. This includes the main topologies for hybrid and all-electric aircraft, with an overview of the ongoing worldwide projects of these types of aircrafts, systematizing the main characteristics of their propulsion systems. It also includes the research on superconducting machines for the purpose of high specific power, considering the impact on the redesign of aircraft systems in the electrical, cooling, and fuel source sense.
Subject: Physical Sciences, General & Theoretical Physics Keywords: charge; current; electric field; magnetic field
Online: 21 June 2019 (08:39:42 CEST)
As we all know, contemporary electromagnetic theory is based on the macroscopic electromagnetic theory established by the 19th century. Because of the lack of microscopic cognition in that era, various electromagnetic phenomena could only be explained and described at the macro level, and their origins could not be explained at the micro level. And because of the microscopic understanding of atomic physics in the 20th century, new progress has been made. Considering that it is now the 21st century, this paper attempts to establish a new theory of microscopic interpretation of classical electromagnetic theory based on the new cognition of atomic physics in the 20th century. Starting from the general assumption, the current will be interpreted as the momentum flow produced by the directed collision between electrons; the charge will be interpreted as a form of expression of electron motion; the voltage is interpreted as the potential difference (energy level difference) of the electron orbit. In the end, this paper successfully developed a new microscopic electromagnetic theory by introducing microscopic atomic physics and rigid body mechanics models to Maxwell's macroscopic electromagnetic theory.
ARTICLE | doi:10.20944/preprints201811.0411.v1
Subject: Materials Science, Nanotechnology Keywords: perovskites; neodymium; luminescence; electric transport; magnetization
Online: 19 November 2018 (03:54:34 CET)
Nanocrystalline La1-xNdxFeO3 powders with different concentrations of Nd3+ have been synthesized by modified Pechini method. Their structure was studied by X-ray powder diffraction (XRD). Further, La1-xNdxFeO3 nanoceramics were prepared by high pressure sintering technique. The luminescence spectra of the powders were investigated as a function of concentration of active dopant to check the possible energy transfers observed due to Nd3+ concentration changes. The electrical and magnetic properties of the powders and ceramics were investigated to determine the effect of Nd3+ doping on the dielectric permittivity and magnetization in the wide frequency range.
ARTICLE | doi:10.20944/preprints202204.0300.v1
Subject: Social Sciences, Other Keywords: agent-based model; electric vehicles; traffic simulation; energy intake; urban environment; fuel costs; public policy; electric mobility
Online: 29 April 2022 (11:05:15 CEST)
By 2020, over 100 countries expanded electric and plug-in hybrid electric vehicle (EV/PHEV) technologies, with global sales surpassing 7 million units. Governments are adopting cleaner vehicle technologies due to proven environmental and health implications of internal combustion engine vehicles (ICEVs), evidenced by the recent COP26 meeting. This article proposes an agent-based model of vehicle activity as a tool for quantifying energy consumption by simulating a fleet of EV/PHEVs within an urban street network at various spatio-temporal resolutions. Driver behaviour plays a significant role in fuel consumption, thus, simulating various levels of individual behaviour enhancing heterogeneity should provide more accurate results of potential energy demand in cities. The study found that 1) energy consumption is lowest when speed limit adherence increases (low variance in behaviour) and is highest when acceleration/deceleration patterns vary (high variance in behaviour) and 2) on average, for tested vehicles, EV/PHEVs were £116.33 cheaper to run than ICEVs across all experiment conditions. The difference in the average fuel costs (electricity and petrol) shrinks at the vehicle level as driver behaviour is less varied (more homogeneous). This research should allow policymakers to quantify the demand for energy and subsequent fuel costs in cities.
Subject: Engineering, Automotive Engineering Keywords: Energy Efficiency; Emissions; Tribology; Lubrication; Battery Electric Vehicles; Hybrid Electric Vehicles; Life Cycle Analysis; Thermal Cooling Fluids
Online: 17 June 2021 (10:46:41 CEST)
The motivations for the move to electrified vehicles are discussed with reference to their improved energy efficiency, their potential for lower CO2 emissions (if the electricity system is decarbonized), their lower (or zero) NOx/particulate matter (PM) tailpipe emissions, and the lower overall costs for owners. Some of the assumptions made in life-cycle CO2 emissions calculations are discussed and the effect of these assumptions on the CO2 benefits of electric vehicles are made clear. A number of new tribological challenges have emerged, particularly for hybrid vehicles that have both a conventional internal combustion engine and a battery, such as the need to protect against the much greater number of stop-starts that the engine will have during its lifetime. In addition, new lubricants are required for electric vehicle transmissions systems. Although full battery electric vehicles (BEVs) will not require engine oils (as there is no engine) they will require a system to cool the batteries – alternative cooling systems are discussed, and where these are fluid based, the specific fluid requirements are outlined.
ARTICLE | doi:10.20944/preprints201705.0116.v1
Subject: Engineering, Mechanical Engineering Keywords: thermal runaway; big-data platform; battery systems; electric vehicles; National Service and Management Center for Electric Vehicles
Online: 16 May 2017 (03:18:57 CEST)
This paper presents a thermal runaway prognosis scheme based on the big-data platform and entropy method for battery systems in electric vehicles. It can simultaneously realize the diagnosis and prognosis of thermal runaway caused by the temperature fault through monitoring battery temperature during vehicular operations. A vast quantity of real-time voltage monitoring data was collected in the National Service and Management Center for Electric Vehicles (NSMC-EV) in Beijing to verify the effectiveness of the presented method. The results show that the proposed method can accurately forecast both the time and location of the temperature fault within battery packs. Furthermore, a temperature security management strategy for thermal runaway is proposed on the basis of the Z-score approach and the abnormity coefficient is set to make real-time precaution of temperature abnormity.
ARTICLE | doi:10.20944/preprints202108.0500.v1
Subject: Chemistry, General & Theoretical Chemistry Keywords: molecular electric potentials; spatial confinement; intermolecular interactions
Online: 26 August 2021 (07:46:43 CEST)
In this theoretical study we report on molecular electrostatic potential (MEP) of titled molecules confined by repulsive potentials of cylindrical symmetry mimicking a topology. Our calculations show that the spatial restriction significantly changes the picture of MEP of molecules in quantitative and qualitative sense. In particular, the drastic changes of MEP as a function of the strength of spatial confinement are observed for the BrCN molecule. This preliminary study is the first step in the investigations of the behavior of MEP of molecular systems under the orbital compression.
ARTICLE | doi:10.20944/preprints202203.0094.v1
Subject: Engineering, Automotive Engineering Keywords: Smart scheduling; Smart Reservations; Reinforcement Learning; Electric vehicle charging; Electric Vehicle Charging Management platform; DQN Reinforcement Learning algorithm
Online: 7 March 2022 (09:20:13 CET)
Abstract: As the policies and regulations currently in place concentrate on environmental protection and greenhouse gas reduction, we are steadily witnessing a shift in the transportation industry towards electromobility. There are, though, several issues that need to be addressed to encourage the adoption of EVs at a larger scale. To this end, we propose a solution capable of addressing multiple EV charging scheduling issues, such as congestion management, scheduling a charging station in advance, and allowing EV drivers to plan optimized long trips using their EVs. The smart charging scheduling system we propose considers a variety of factors such as battery charge level, trip distance, nearby charging stations, other appointments, and average speed. Given the scarcity of data sets required to train the Reinforcement Learning algorithms, the novelty of the recommended solution lies in the scenario simulator, which generates the labelled datasets needed to train the algorithm. Based on the generated scenarios, we created and trained a neural network that uses a history of previous situations to identify the optimal charging station and time interval for recharging. The results are promising and for future work we are planning to train the DQN model using real-world data.
ARTICLE | doi:10.20944/preprints201801.0224.v1
Subject: Engineering, Civil Engineering Keywords: steel slag; EOS (Electric Arc Furnace Oxidizing Slag); ERS (Electric Arc Furnace Reduction Slag); cement mortar; Length change rate
Online: 24 January 2018 (08:04:44 CET)
Recently many researches of EOS (Electric Arc Furnace Oxidizing Slag) on application to construction industry have been carried out with increasing its production and limited reclamation site. EOS can be used as a fine aggregate for construction material, however, its engineering properties vary with the manufacturing process and producing district, causing a quality differences in material performance. In the work, EOS is obtained from steel manufacturing plants in South Korea and the engineering properties are evaluated for EOS and the cement mortar with EOS, respectively. From the tests, EOS is mainly made up of CaO, SiO2, and FeO with 18.2% of larnite which has a crystal structure of β-C2S with similar cement mineral. EOS mortar shows an increasing compressive strength with more EOS content, which is affected by a considerable amount of larnite (β-C2S) in EOS. The EOS based mortar with ERS (Electric Arc Furnace Reduction Slag) shows unsatisfactory results over the criteria for rate of change, which implies that more consideration must be taken for the usage of the mixed ERS and EOS for cement mortar due to swelling effect of ERS on dimensional stability.
ARTICLE | doi:10.20944/preprints202110.0144.v1
Subject: Physical Sciences, Optics Keywords: Plasmonic nanoantenna; Electric field norm; Tilted light incidence
Online: 8 October 2021 (13:43:07 CEST)
We study the effect of oblique illumination on the functioning of a plasmonic nanoantenna for chiral light. The antenna is designed to receive a structured beam of light and produce a nanosized near-field distribution that possesses non-zero orbital angular momentum. The design consists of metal (gold) micro-rods laid on a dielectric surface and is compatible with well-developed nanofabrication techniques. Experimental arrangements often require such an antenna to operate in a tilted geometry, where input light is incident on the antenna at an oblique angle. We analyze the limitations that the angled illumination imposes and discuss approaches to mitigate these limitations. Through our numerical simulations, we find that tilt angles larger than 30 degrees require modifications to the antenna design. Our analysis guides current and future experimental configurations to pushing the limits of resolution and sensitivity.
ARTICLE | doi:10.20944/preprints202002.0275.v3
Subject: Physical Sciences, Particle & Field Physics Keywords: anomalous electric dipole moment; isospin; gravitational Dirac particle
Online: 26 July 2021 (12:07:54 CEST)
An analysis is presented of the possible existence of a second anomalous dipole moment of Dirac’s particle next to the one associated with the angular momentum. It includes a discussion why, in spite of his own derivation, Dirac has doubted about its relevancy. It is shown why since then it has been overlooked and why it has vanished from leading textbooks. A critical survey is given on the reasons of its reject, including the failure of attempts to measure and the perceived violations of time reversal symmetry and charge-parity symmetry. It is emphasized that the anomalous electric dipole moment of the pointlike electron (AEDM) is fundamentally different from the quantum field type electric dipole moment of an electron (eEDM) as defined in the standard model of particle physics. The analysis has resulted into the identification of a third type Dirac particle, next to the electron type and the Majorana particle. It is shown that, unlike as in the case of the electron type, its second anomalous dipole moment is real valued and is therefore subject to polarization in a vector field. Examples are given that it may have a possible impact in the nuclear domain and in the gravitational domain.
ARTICLE | doi:10.20944/preprints202106.0694.v1
Subject: Behavioral Sciences, Applied Psychology Keywords: Electric energy; Occupant behavior; energy efficiency; lecture halls
Online: 29 June 2021 (08:44:05 CEST)
All over the world energy is used for different purposes and hence its continuous high demand which has brought about an increase in crisis and prices of energy. Ghana has faced a lot of supply and high electricity consumption challenges over a period of time. The Energy Commission of Ghana has developed regulations and guidelines to help reduce high consumption challenges among users, these included the replacement of incandescent bulbs with fluorescent bulbs, ban of importation of low energy efficient appliances. In spite of the effort to reduce electricity wastage, there is still a high increase in electricity consumption. The research investigated what contributed to electricity consumption in Kwame Nkrumah University of Science and Technology with the lecture halls as the main focus, the research also analyzed the current occupant behavior characterized by the electrical energy consumption practices. And investigated how the contemporary theories for reducing energy consumption was used in the lecture halls. A questionnaire survey was conducted to investigate occupants on their energy use practices in lecture halls that causes wastages, observation was made to establish relevant data on the use of contemporary theories for energy reduction in lecture halls. In a total of 110 occupants that responded to the questionnaire, 79 occupants almost always turn off electrical fitting and fixtures when not in use. From the responses, a majority of the occupants claimed to comply to best practices of energy use. The research concluded that some contemporary theories to reduce energy consumptions was not used and considered in the lecture halls.
ARTICLE | doi:10.20944/preprints202106.0475.v1
Subject: Life Sciences, Biochemistry Keywords: axon, neuron, electric circuit, capacitance , biophysics, HH model
Online: 18 June 2021 (11:08:11 CEST)
The most common and taught membrane theory assumes that the membrane behaves as a kind of electrical capacitance that is exposed to an electrical current generated by an ionic flow. If this statement is verifiable, it can be confirmed by the laws of physics, mathematics and in particular electricity. We will demonstrate that this hypothesis is not verified and that it is necessary to modify biophysics according to already established and experimentally verified principles of physics.
ARTICLE | doi:10.20944/preprints202209.0047.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: colorectal neoplasm; nutrition assessment; body composition; electric impedance; prognosis
Online: 5 September 2022 (07:33:30 CEST)
Background: Some studies have shown that an increase in visceral fat is associated with postoperative clinical and oncologic outcomes. However, no studies have used bioelectrical impedance analysis (BIA) to determine the effects of visceral fat on the oncologic outcomes of colorectal cancer (CRC). This study aimed to investigate the relationship between visceral fat area (VFA) and clinical, and oncologic outcomes in CRC. Methods: This study included 203 patients who underwent anthropometric measurements by BIA before surgical treatment for CRC between January 2016 and June 2020. Results: According to the cutoff level of VFA by receiver operating characteristic curve analysis, 85 (40.5%) patients had a low VFA, and 119 (59.5%) had a high VFA. Multivariate analysis found that preoperative CRP (hazard ratio [HR], 3.882; 95% confidence interval [CI], 1.001–15.051; p=0.050) and nodal stage (HR, 7.996; 95% CI, 1.414–45.209; p=0.019) were independent prognostic factors for overall survival, while sex (HR, 0.110; 95% CI, 0.013–0.905; p=0.040), lymphovascular invasion (HR, 3.560; 95% CI, 1.098–11.544; p=0.034), and VFA (HR, 4.263; 95% CI, 1.280–14.196; p=0.040) were independent prognostic factors for disease-free survival (DFS). Conclusion: High VFA preoperatively measured by BIA was associated with inflammations and was an independent prognostic factor for DFS.
ARTICLE | doi:10.20944/preprints202202.0247.v2
Subject: Engineering, Other Keywords: cost estimation; all-electric aircraft; European air traffic network
Online: 17 March 2022 (09:04:29 CET)
Aircraft emissions represent a relevant amount of human induced CO2. Globally, up to 2.5 per cent of such emissions stem from the aviation industry. In order to investigate the effects within the atmosphere, realistic flight profiles are necessary to provide quantitatively tangible values of emissions. The flight profiles and the according fuel consumption can be calculated by using waypoints from flight plans and Base of Aircraft Data (BADA). This paper presents an approach to refine the fuel consumption by integrating the passenger load into the calculation. Since effects of emissions have to be assessed on a greater scale, such as on the European air traffic network, the presented approach provides cost functions for CO2 emissions for different aircraft types and load factors. The cost functions were derived by means of regression analyses of BADA based calculated flight profiles with a step size of one second. The calculations are based on real historic traffic scenarios of several days. The derived aircraft specific fuel burn coefficients enable a simple and efficient integration of CO2 estimations depending on the flight distance, load factor and aircraft type. This can be applied to large traffic scenarios to also study different set-ups such as travel restrictions, other disruptions or an alteration in the traffic system as a whole. In order to enable the assessment of further aspects of such changes to the European air traffic system at large and to foster reproducibility and comparability of related studies, we provide further general-purpose cost estimation functions for several important key characteristics. Besides fuel consumption, we develop cost estimations for air navigation fees and maintenance for conventional aircraft. Those functions are also provided for the design concept of a short-range all-electric aircraft. This propeller aircraft features game-changing technologies such as active laminar flow control, active load alleviation and advanced materials and structure concepts. The approaches discussed in this paper will focus on the generic aspects of aircraft related costs, which can be derived from general available data. For the sake of reproducibility, the results will be made publicly available.
COMMUNICATION | doi:10.20944/preprints202201.0051.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Electric vehicles; Battery thermal management system; Li-Ion batteries
Online: 6 January 2022 (09:39:49 CET)
Electric Vehicles (EVs) are the need of the hour due to growing climate change problems linked with the transportation sector. Battery Thermal Management System (BTMS), which is accountable for certifying safety and performance of lithium-ion batteries (LiB), is the most vital part of an EV. LiB has auspicious gravimetric energy density but the heat generation due to chemical reactions inside a LiB during charging and discharging causes temperature rise which has a direct effect on LiB performance and safety. This study specifically focuses on aircooled BTMS, defines different types of air-cooled BTMS (active and Passive), discusses limitations associated with air-cooled BTMS, and investigates different optimization techniques and parameters to improve performance of air-cooled BTMS. Maintaining temperature within optimum range and uniform temperature distribution between cells of a battery pack are the major design parameters for improving the performance and efficiency of air-cooled BTMS. Various optimization techniques including cell arrangement with a battery pack, air-flow channel optimization, and air inlet/outlet position variations are discussed and each technique is thoroughly reviewed. Finally, it’s noted that passive air-cooled BTMS is not that effective for long-distance vehicles so most researchers shifted their focus toward active air-cooled BTMS. Active air-cooled BTMS requires a lot of power for effective performance. Lastly, the most recent field of air-cooled BTMS technology which is Air-Hybrid BTMS is discussed and declared a very promising solution for overcoming major limitations associated with air-cooled BTMS.
ARTICLE | doi:10.20944/preprints202105.0607.v2
Subject: Physical Sciences, General & Theoretical Physics Keywords: Gravitational-electric-magnetic interaction; Controlling permittivity and permeability; Superconductivity
Online: 13 September 2021 (12:31:14 CEST)
Appling the controlling relative permittivity and permeability in the equations for the gravitational-magnetic-electric field interaction, a very large variation of the gravitational acceleration of the Earth by electric/magnetic field could be arrived at. This conclusion may be supported by some of the experiments for the gravitational effect of superconductivity.
REVIEW | doi:10.20944/preprints202104.0109.v1
Subject: Biology, Physiology Keywords: Leptin, Animal Communication, Electric Fish, Singing Mice, Metabolism, Energetics
Online: 5 April 2021 (12:11:15 CEST)
Animal communication signals are regulated by multiple hormonal axes that ensure appropriate signal targeting, timing, and information content. The regulatory roles of steroid hormones and many peptide hormones are well understood and documented across a wide range of vertebrate taxa. Two recent studies have reported a novel function for leptin, a peptide hormone central to energy balance regulation: regulating communication signals of weakly electric fish and singing mice. With only limited evidence available at this time, a key question is just how widespread leptinergic regulation of communication signals is within and across taxa. A second important question is what features of communication signals are subject to leptinergic regulation. Here we consider the functional significance of leptinergic regulation of animal communication signals in the context of both direct and indirect signal metabolic costs. Direct costs arise from metabolic investment in signal production, while indirect costs arise from the predation and social conflict consequences of the signal’s information content. We propose a preliminary conceptual framework for predicting which species will exhibit leptinergic regulation of their communication signals and which signal features leptin will regulate. This framework suggests a number of directly testable predictions within and across taxa. Accounting for additional factors such as life history and reproductive strategies will likely require modification or elaboration of this model.
ARTICLE | doi:10.20944/preprints202101.0029.v1
Subject: Social Sciences, Accounting Keywords: electric mobility; paratransit; informality; Sustainability transitions; East-Africa; transport
Online: 4 January 2021 (12:23:46 CET)
Electric mobility begins to enter East-African markets. This paper aims to investigate what policy level solutions and stakeholder constellations are established in the context of e-mobility in Dar es Salaam, Kigali, Kisumu and Nairobi and in which ways they attempt to tackle implementation of electric mobility solutions. The study employs two key methods including content analysis of policy and programmatic documents as well as interviews based on purposive sampling ap-proach with stakeholders involved in mobility transitions. The study findings point out that transport operators and their representative associations are less recognized as major players in the transition, far behind new e-mobility players (start-ups) and public authorities. The study further indicates that a set of financial and technical barriers persist such as high upfront invest-ment costs in vehicles and infrastructure, or anxieties regarding competitiveness with fossil fuel vehicles, that constrain the uptake of such private e-mobility initiatives. This study concludes by identifying current gaps that need to be tackled by policy makers and stakeholders in order to implement inclusive electric mobility in East-African cities, considering modalities that include transport providers and address their financial constraints.
ARTICLE | doi:10.20944/preprints202012.0323.v1
Subject: Physical Sciences, Acoustics Keywords: nematic interaction; Coulomb fluids; nematic wetting; electric double layer
Online: 14 December 2020 (10:52:32 CET)
A field theoretic representation of the classical partition function is derived for a system composed of a mixture of anisotropic and isotropic mobile charges that interact via long range Coulomb and short range nematic interactions. The field theory is then solved on a saddle-point approximation level, leading to a coupled system of Poisson-Boltzmann and Maier-Saupe equations. Explicit solutions are finally obtained for a calamitic counterion-only system in proximity of a charged planar wall. The nematic order parameter profile, the counterion density profile and the electrostatic potential profile are interpreted within the framework of a nematic-isotropic wetting phase with a Donnan potential difference.
ARTICLE | doi:10.20944/preprints202001.0334.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Russia; solar power; hydrogen energy; electric vehicle; lithium battery
Online: 28 January 2020 (05:47:34 CET)
With a relatively small population, Russia accesses huge oil, natural gas, coal and uranium resources, and hosts advanced nuclear energy, oil and natural gas industries. However, the combined effect of today’s low cost electricity generation via photovoltaic modules, water and wind turbines and similarly low cost storage in Li-ion battery and solar hydrogen obtained via water electrolysis will have a profound impact on Russia’s energy and automotive industries.
ARTICLE | doi:10.20944/preprints202001.0287.v1
Subject: Engineering, Mechanical Engineering Keywords: wheelchair; hybrid manual-electric drives; drives supporting the movement
Online: 24 January 2020 (15:00:13 CET)
Overcoming terrain obstacles presents a major problem for people with disabilities or with limited mobility who are dependent on wheelchairs. An engineering solution designed to facilitate the use of wheelchairs are assisted propulsion systems. The objective of the research described in this article is to analyse the impact of the hybrid manual-electric wheelchair propulsion system on the kinematics of the anthropotechnical system when climbing hills. The tests were carried out on a wheelchair ramp with an incline degree of 4°, using a prototype wheelchair with a hybrid manual-electric propulsion system in accordance with the patent application P.427855. The test subjects were three people whose task was to propel the wheelchair in two assistance modes supporting manual propulsion. The first mode is hill climbing assistance, while the second one is assistance with propulsion torque in the propulsive phase. During the tests, a number of kinematic parameters of the wheelchair were monitored. An in-depth analysis was performed for the amplitude of speed during a hill climb and the number of propulsive cycles performed on a hill. The tests performed showed that when propelling the wheelchair only using the hand rims, the subject needed an average of 13 pushes on the uphill slope, and their speed amplitude was 1.8 km/h with an average speed of 1.73 km/h. The climbing assistance mode reduced the speed amplitude to 0.76 km/h, while the torque assisted mode in the propulsive phase reduced the number of cycles required to climb the hill from 13 to 6. The tests were carried out at various values of assistance and assistance amplification coefficient, and the most optimally selected parameters of this coefficient were presented in the results. The tests proved that electric propulsion assistance has a beneficial and significant impact on the kinematics of manual wheelchair propulsion when compared to a classic manual propulsion system when overcoming hills. In addition, assistance and assistance amplification coefficient were proved to be correlated to operating conditions and the user's individual characteristics.
REVIEW | doi:10.20944/preprints201905.0256.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: electric field screen; pest management; photo-selective nets; whiteflies
Online: 21 May 2019 (09:08:24 CEST)
Applied electrostatic engineering can be used to construct greenhouses that prevent entry of insect pests. Two types of electric field screen were used to exclude pests from the greenhouse: single- and double-charged dipolar electric field screens (S- and D-screen, respectively). The S-screen consisted of iron insulated conductor wires (ICWs) arrayed in parallel (ICW-layer), a grounded metal net on either side of the ICW-layer, and a direct current voltage generator. S-screens were attached to the side windows of the greenhouse to repel whiteflies (Bemisia tabaci) that approached the nets. The D-screen was installed in a small anteroom at the greenhouse entrance to capture whiteflies entering through it. The ICW-layers of the D-screen were oppositely charged with equal voltages and arrayed alternately, and an insulator board or grounded metal net was placed on one side of the ICW-layer. The ICW-layers captured whiteflies entering the electric field of the double-charged dipolar electric field. Three screens equipped with yellow or gray boards or a grounded metal net were installed in the anteroom based on the airflow inside the room, as most whiteflies were brought in by air when the door was opened. Two D-screens with boards were useful for directing the airflow toward the wall with the netted D-screen. This screen eliminated the insects and the pest-free air was circulated inside the greenhouse. The D-screen with the yellow board attracted the whiteflies and was effective for trapping them when there was no wind. Our method kept the greenhouse pest-free throughout the entire period of tomato (Solanum lycopersicum) cultivation.
ARTICLE | doi:10.20944/preprints201902.0174.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Robotic Hands, Grasping, Electric Power Quality, Voltage Dips effects
Online: 19 February 2019 (10:48:50 CET)
This paper addresses the effects of electric power quality on robotics operation. A general overview is reported to highlight the main characteristics of electric power quality and their effects on a powered system by considering an end-users viewpoint. Then, authors outline the influence of voltage dip effects by focusing at robotic grasping applications. A specific case of study is reported as referring to LARM Hand IV, a three-fingers robotic hand, which has been designed and built at LARM in Cassino. A dedicated test rig has been settled up for generating predefined voltage dips. Experimental tests are carried out for evaluating the effects of different types of voltage dips on the grasping of objects.
ARTICLE | doi:10.20944/preprints201806.0383.v1
Subject: Physical Sciences, Nuclear & High Energy Physics Keywords: Quantum Field Theory, Electric-Magnetic Duality, Spin-Mass Duality
Online: 25 June 2018 (11:14:54 CEST)
Abstract: I present a generalization of quantum electrodynamics which includes Diracmagnetic monop oles and the Salam magnetic photon. This quantum electromagnetodynamics has many attractive features. (1) It explains the quantization of electric charge. (2) It describes symmetrized Maxwell equations. (3) It is manifestly covariant. (4) It describes local four-potentials. (5) It avoids the unphysical Dirac string. (6) It predicts a second kind of electromagnetic radiation which can be veried by a tabletop experiment. An eect of this radiation may have been observed by August Kundt in 1885. Furthermore I discuss a generalization of General Relativity which includes Cartan's torsion. I discuss the mathematical denition, concrete description, and physical meaning of Cartan's torsion. I argue that the electric-magnetic duality of quantum electromagnetodynamics is analogous to the spin-mass duality of Einstein-Cartan theory. A quantum version of this theory requires that the torsion tensor corresponds to a spin-3 boson called tordion which is shown to have a rest mass close to the Planck mass. Moreover I present an empirically satised fundamental equation of unied eld theory which includes the fundamental constants of electromagnetism and gravity. I conclude with the remark that the concepts presented here require neither Grand Unication nor supersymmetry.
ARTICLE | doi:10.20944/preprints201709.0124.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: partial discharge; Weibull distribution; XLPE cable; electric tree; diagnosis
Online: 25 September 2017 (16:47:35 CEST)
The main purpose of this paper is to evaluate electrical treeing degradation for cable insulation. To effectively deal with the currently facing issues, I endeavor to find the most optimal methods by means of applying signal process. First, we made three type models of electrical tree for PD generation to show the distribution characteristics and applied voltage to acquire data by using a PD detecting system. These acquired data presented distribution and four 2D distributions. Hn(q), Hn(), Hqn(), and Hqmax() were derived from the distribution of partial discharge. From the analysis of these distributions, each PD model is proved to hold its unique characteristics and the results were then applied as basic specific qualities for insulation conditions. In order to recognize the progresses of an electrical tree, we proposed methods using scale parameter by means of Weibull distribution. We measured the time of tree propagation for 16 specimens of each model from initiation stage, middle stage, and breakdown respectively, using these breakdown data, we estimated the shape parameter, scale parameter and MTTF(Mean Time To Failure). The results of this study recognize the sources of PD by applying acquired data from PD signals to pre-acquired data. If the cause of PD is degradation, in other words, electrical tree, we can determine the replacement time of devices at the initiation stage of tree growth progress or no later than the middle stage and use it as a basic methods analysis diagnosis system. That is, pattern recognition and Weibull distribution can be employed to get the reliability of diagnosis.
ARTICLE | doi:10.20944/preprints202105.0226.v2
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: energy efficiency; electric drive; electric motor control; frequency converter; Industrial Internet of Things; edge computing; Big Data; Key Performance Indicators; KPI; dashboard
Online: 8 September 2021 (13:15:18 CEST)
The article presents a method of generating Key Performance Indicators related to electric motor energy efficiency on the basis of Big Data gathered and processed in frequency converter. The authors proved that using the proposed solution it is possible to specify the relation between the control mode of an electric drive and the control quality-energy consumption ratio in the start-up phase as well as in the steady operation with various mechanical loads. The tests were carried out on a stand equipped with two electric motors (one driving, the other used to apply the load by adjusting the parameters of the built-in brake). The measurements were made in two load cases, for motor control modes available in industrially applied frequency converters (scalar V/f, vector Voltage Flux Control without encoder, vector Voltage Flux Control with encoder, vector Current Flux Control and Vector Current Flux Control with torque control). During the experiments values of current intensities (active and output), the actual frequency value, IxT utilization factor, relative torque and the current rotational speed were measured and processed. Based on the data the level of the energy efficiency was determined for various control modes.
ARTICLE | doi:10.20944/preprints201907.0082.v1
Subject: Physical Sciences, Applied Physics Keywords: current source; diode; divergent current density; new superconductivity type; zero voltage; symmetric electric circuit; Meissner effect; electric potential; vector potential; Lorentz conservation law
Online: 4 July 2019 (17:26:56 CEST)
This paper proposes a method of extracting energy from zero-point energy and evaluates the amount of energy gained. In addition, this electric circuit-based approach exhibits the Meissner effect, suggesting a new type of superconductivity that does not require refrigeration. The proposed method can provide extremely large amounts of energy, which is more than a conventional power station, without consuming fossil fuels or emitting radiation. Thus, it has the potential to solve the global energy problem. It involves preparing two electric loops containing diodes and connecting the loops together with current sources. The diodes are oriented in the same direction within each loop but in opposite directions in different loops. With this setup, the currents from the current sources build iteratively within the loops, resulting in large output currents. Our numerical analysis indicates that extremely large electric potentials are produced, which in turn yield large output currents. In addition, we confirm numerically that the voltage is zero around a loop and show analytically that the Meissner effect is present, proving the existence of a new type of superconductivity. Furthermore, when we introduce induction coils to not break the loop’s symmetry, they store extremely large amounts of energy and we can thus obtain energy from them via discharge currents.
REVIEW | doi:10.20944/preprints202208.0448.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Electric Vehicles; Review; SOC Estimation; Deep Learning; Lithium-ion Battery
Online: 26 August 2022 (04:43:03 CEST)
As one of the critical state parameters of the battery management system, lithium battery state of charge (SOC) can provide an essential reference for battery safety management, charge/discharge control, and energy management of electric vehicles. To analyze the application of deep learning in electric vehicle power battery SOC estimation, this study reviewed the technical process, common public datasets, and the neural networks used, structural characteristics, advantages and disadvantages of lithium battery SOC estimation in deep learning method. First, the specific technical processes of the deep learning method for SOC estimation were analyzed, including data collection, data preprocessing, feature engineering, model training, and model evaluation. Secondly, the current commonly and publicly used lithium battery dataset was summarized. Then, the input variables, data sets, errors, and advantages and disadvantages of four types of deep learning methods, were concluded using the structure of neural network used for training as the classification criterion. Finally, the challenges and future development directions of lithium battery SOC estimation in deep learning method were explained.
ARTICLE | doi:10.20944/preprints202108.0166.v1
Subject: Engineering, Automotive Engineering Keywords: electric weapons; rail gun; electromagnetic ammunition; hybrid technologies; plasma detonator.
Online: 6 August 2021 (14:00:09 CEST)
Although the idea of making electric weapons has emerged since the beginning of the 20th Century, the great number of technological problems made that such technology was not developed. During the Cold War, the US strategic programme Space Defensive Initiative paid a special attention to this category of weapons, but the experiments have demonstrated that the prototypes are too big, very heavy, and involve a very high energy consumption and low reliability. Under these circumstances, the authors have noticed the trend to design new types of electric weapons starting from the hybridization of some technologies: the compressed flux weapons, the plasma electromagnetic cannon, the electromagnetic weapons as the coil-gun and rail-gun.
ARTICLE | doi:10.20944/preprints202104.0406.v1
Subject: Earth Sciences, Geology Keywords: Electric tomography; three-dimensional; electrodes; seat control; foundations; stabilization methodology.
Online: 15 April 2021 (10:50:51 CEST)
The paper proposes a novel methodology for the stabilization of shallow foundations, with a simplified model combined with 3D Electrical resistivity tomography (ERT-3D) and conso- lidation injections. To determine its usefulness, the method has been applied in a case located in Estepona (southern Spain). The chosen tomography model is the dipole-dipole configuration, with an optimized distance between electrodes of 0.80 m for a better visualization of the foundation subsoil; with this parameterization, a total of 72 electrodes were installed in the analyzed case. In this work, the depth of the anomaly in the building's supporting subsoil was detected ranging from 2.00 m to 3.90 m deep. The study also delineates areas of high resistivity variations (50-1,000 Ω m) in the middle and eastern end of the field. These data have been validated and corroborated with a field campaign. The results of the ERT-3D monitoring are presented, once the investment data has been processed with the RES3DINV software, from the beginning to the end of the stabilization intervention. The novelty occurs with the interaction between the tomography and the foundation consolidation injections, until the final stabilization; very useful methodology in case of emergency consolidation, where there is a need to minimize damage to the building. Thus, people using this combined system; will be able to practically solve the initial anomalies of the subsoil that caused the damages, in a non-invasive way, considerably lowering the value of the resistivities.
ARTICLE | doi:10.20944/preprints201906.0142.v4
Subject: Physical Sciences, Nuclear & High Energy Physics Keywords: anomalous electric dipole moment; Dirac particle; Pauli’s spin vector; isospin
Online: 26 November 2019 (03:57:09 CET)
An analysis is presented of the possible existence of a second anomalous dipole moment of Dirac’s particle next to the angular one. It includes a discussion why, in spite of his own derivation, Dirac has doubted about its relevancy. It is shown why since then it has been overlooked and why it has vanished from leading textbooks. A critical survey is given on the reasons of its reject, including the failure of attempts to measure and the perceived violations of time reversal symmetry and chargeparity symmetry. It is emphasized that the anomalous electric dipole moment of the pointlike electron (AEDM) is fundamentally different from the quantum field type electric dipole moment of an electron (eEDM) as defined in the standard model of particle physics and that its measurement requires different instrumentation. A proposal has been described how to prove or disprove its existence by experiment. Moreover, by reference from literature, the possible impact is discussed in the nuclear domain and in the gravitational domain.
ARTICLE | doi:10.20944/preprints201905.0012.v1
Subject: Chemistry, Other Keywords: lithium-ion battery; battery recycling; battery electric vehicle; circular economy
Online: 5 May 2019 (11:10:23 CEST)
Driven by the rapid uptake of battery electric vehicles, Li-ion power batteries are increasingly reused in stationary energy storage systems, and eventually recycled to recover all the valued components. Offering an updated global perspective, this study provides a circular economy insight on lithium-ion battery reuse and recycling.
ARTICLE | doi:10.20944/preprints201805.0268.v1
Subject: Chemistry, Chemical Engineering Keywords: electric field; oxidative dehydrogenation; LPG, Cr-/HZSM-5; electrical properties
Online: 21 May 2018 (11:32:11 CEST)
CrHZSM-5 was placed in an electric field with appropriate strength in a quartz packed bed reactor with CO2 as oxidant to analyze its catalytic activity. Olefin yield increases with decrease in band gap since lattice oxygen mobility increases by reducing band gap. Fermi level change at the catalyst surface affects the catalytic activity. One way to change Fermi level is use electric field. In high voltage electric field, energy band was curved, bending of the energy band promoted the activity and Fermi level position is increasing. The CCD experiments were carried out with Design-Expert 7.3 software to determine the interaction between four operating variables, namely: temperature, electrical current, gap distance and metal loading. The levels of the independent variables were: temperature (550-700 °C), electrical current (0-12 mA), gap distance (6-14 mm), metal loading (0.5-7.5 %wt.). The conversion of LPG (Liquefied petroleum gas) was greatly increased by weak and effective application of an electric field to the catalyst bed. The obtained results indicated that the maximum yield value (46.94%) can be achieved under 673.66 °C, input electrical current of 11.01 mA, gap distance of 6.55 mm and metal loading of 3.98 wt.%.
ARTICLE | doi:10.20944/preprints201703.0060.v1
Subject: Chemistry, Inorganic & Nuclear Chemistry Keywords: elasticbiomass; tubular structure; interconnected porous carbon; electric double layer capacitance
Online: 13 March 2017 (08:01:13 CET)
Biomass materials have received attention for energy storagebecaused of the advantage of low-cost, easy-to-prepare, and eco-friendliness. Three-dimensional carbon materialswith abundant pore structure gradually becomeresearch hotspot in high-performance energy storage. In this study, an easy-to-prepare, green, light and elastic activated carbon was present using the biomass Juncus effusus (JCE) via high-temperature pyrolysis, followed by activation in air. Compared with previously reported bio-carbons, the proposed air-activated bio-carbon contributes in the fabrication of pores to preserve the interconnected, reticular and tubular structure. Moreover, the interconnected porous material also inherits the excellent tenacity of the original JCE such as the material can be bended to below 90o under an external force while maintaining structural integrity. The activated porous carbon material exhibits an enhanced electric double-layer capacitance (~210 F g-1 at 1 A g-1), with capacitance retention of ~78.62% at 10 A g-1. The interconnected porous carbon microtubes electrode as a double-layer symmetric capacitor exhibits considerable capacitance retention (84%) after 2000 cycles at 1 A g-1. The improved energy storage performance was proposed to be attributed to the shortened ionic diffusion distance and sufficient contact between the interface of the carbon electrode and electrolyte, which is resulted from the elastic, undamaged structure and types of pores. These results demonstrated that as-preparedcarbon materials have potentional application in symmetric capacitors.
ARTICLE | doi:10.20944/preprints201703.0045.v1
Subject: Keywords: longitudinal sound wave; electric field; electrons; kinetic equation; sound attenuation
Online: 8 March 2017 (05:27:52 CET)
In the present work the problem of the attenuation of longitudinal sound oscillations in a conducting medium are considered. The proposed approach is based on the dynamic interaction of electron gas with the lattice vibrations. This interaction is manifested in the modification of kinetic equation for electrons. The process is accompanied by generation of an electric field.
ARTICLE | doi:10.20944/preprints201612.0030.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: microgrid; classification; simulation; optimization; renewable energy sources; storage; electric vehicles
Online: 6 December 2016 (07:52:50 CET)
The expansion of renewable energies is progressing strongly. The influence on the power supply networks by the volatility of the infeed must be met with new concepts. In this paper we investigate the possibilities of integrating microgrids as a cooperating unit in the power supply network to support further expansion of RES power plants. In this paper a differentiation of microgrids from similar network structures is established, a classification of proposed groups is made. Then, after the description of simulation of components in a microgrid, with practical advice, an example model is shown, which aids the dimensioning of the components within a microgrid to achieve a specified goal.
ARTICLE | doi:10.20944/preprints202207.0087.v1
Subject: Chemistry, Food Chemistry Keywords: millet porridge; electric cooker; nutritional composition; principal component analysis; cluster analysis
Online: 6 July 2022 (04:38:57 CEST)
(1) Background: In order to study the effects of different electric cookers on the nutritional components of millet porridge, five different electric cookers were selected to cook millet porridge, and sensory and nutritional components in millet porridge, millet soup, and millet grains were analyzed. (2) Methods: Using principal component and cluster analysis, a variety of nutritional components were comprehensively compared. (3) Results: The results showed that among the different cooked samples, the content of amylose and reducing sugar was the highest in the samples cooked by electric cooker no. 3. The electric cooker no. 4 samples had the highest sensory evaluation score, crude fat, and protein content. The contents of ash, fatty acids, bound amino acids, and minerals were the highest in the electric cooker no. 5 samples. The sensory evaluation score and content of crude fat, ash, reducing sugar, direct starch, and Cu were higher in millet grains than in millet soup or porridge. The content of fatty acid, protein, amino acid, Zn, Fe, Mg, Mn, and Ca was highest in millet soup. Different electric cookers produced millet porridge with varying nutritional levels. (4) Conclusions: This study provides a reference for the further development of new electric cookers.
ARTICLE | doi:10.20944/preprints202203.0321.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric vehicle; electromagnetic model; optimization; silicon-iron; thermal model; Vanadium Cobalt
Online: 24 March 2022 (02:59:21 CET)
The use of cobalt-iron (VaCoFe) core is investigated as an alternative to silicon-iron (FeSi) on the design of interior permanent magnet synchronous motors (IPMSM). A spoke-type IPMSM geometry is optimized considering FeSi and VaCoFe cores for a torque range up to 40 N.m, providing a general comparative analysis between materials, considering the application of a 4-motor competition vehicle’s powertrain. A genetic optimization algorithm is applied over a hybrid analytical/finite-element model of the motor to provide sufficiently accurate electromagnetic and thermal results within a feasible time. VaCoFe can result in an estimated increase of up to 5 % in efficiency for the same torque, or up to 64 % torque increase for the same efficiency level. After optimization, and using a detailed time-dependent model, a potential 3.2 % increase in efficiency, a core weight reduction of 4.1 %, and a decrease of 9.6 % in the motor’s core volume was found for the VaCoFe at 20 Nm. In addition, for the same motor volume, the VaCoFe allows an increase of 51.9 % of torque with an increase of 1.1 % of efficiency, when compared with FeSi.
COMMUNICATION | doi:10.20944/preprints202109.0042.v1
Subject: Engineering, Control & Systems Engineering Keywords: unmanned aerial vehicle; more electric aircraft; turbofan engine; distributed control system
Online: 2 September 2021 (13:48:38 CEST)
The article presents development of the more electric turbofan engine in distributed architecture with a design thrust in the range from 3 to 7.5 and from 7.5 to 30 kN for small and medium-sized unmanned aerial vehicles. The engine subsystems are considered as separate smart modules with a built-in control system, exchanging data via a digital channel with the central engine control and diagnostics unit. The key smart engine units are combined in the following subsystems: starter and turbine generators, oil pumps, actuator of guide vanes, fuel pumps, fuel metering unit, control and diagnostic unit. All pumps and guide vane actuator are electrically driven. Control and monitoring signals are transmitted via a digital bus. Functional and reliability analysis, technical configuration design of each subsystem are presented. Based on analysis of the architecture of distributed control system for gearbox-free more electric engine, different configurations of described subsystems are proposed.
Subject: Physical Sciences, Condensed Matter Physics Keywords: multiferroics; metal-organic perovskites; magneto-electric effect; magnetic anisotropy, canted antiferromagnet
Online: 18 February 2021 (10:36:42 CET)
Hybrid metal-organic compounds as relatively new and prosperous magnetoelectric multiferroics provide opportunities to improve the polarization, magnetization and magneto-electric coupling at the same time, which usually have some limitations in the common type-I and type-II multiferroics. In this work we investigate the crystal of guanidinium copper(II) formate [C(NH2)3]Cu(HCOO)3 and give novel insights concerning the structure, magnetic, electric and magneto-electric behaviour of this interesting material. Detailed analysis of crystal structure at 100 K is given. Magnetization points to the copper(II)-formate spin-chain phase that becomes ordered below 4.6 K into the canted antiferromagnetic (AFM) state, as a result of super-exchange interaction over different formate bridges. The performed ab-initio colinear density functional theory (DFT) calculation confirm the AFM-like ground state as a first approximation and explain the coupling of spin-chains into the AFM ordered lattice. In versatile measurements of magnetization of a crystal, including transverse component besides the longitudinal one, very large anisotropy is found that might originate from canting of the coordination octahedra around copper(II) in cooperation with the canted AFM order. With cooling down in zero fields the generation of spontaneous polarization is observed step-wise below 270 K and 210 K and the effect of magnetic field on its value is observed also in the paramagnetic phase. Measured polarization is somewhat smaller than the DFT value in the c-direction, possibly due to twin domains present in the crystal. The considerable magneto-electric coupling below the magnetic transition temperature is measured with different orientations of the crystal in magnetic field, giving altogether the new light onto the magneto-electric effect in this material.
ARTICLE | doi:10.20944/preprints201909.0261.v1
Subject: Engineering, Civil Engineering Keywords: nuclear power plant; electric cabinet; tuned mass damper; earthquake; vibration control
Online: 23 September 2019 (06:13:10 CEST)
In this study, a tuned mass damper is proposed as a seismic acceleration mitigating technique of an electrical cabinet inside the nuclear power plant. In order to know the mitigation performance, the electrical cabinet and the tuned mass damper were modeled using SAP2000. The sine sweep wave was used to confirm the vibration characteristics of the cabinet over a wide frequency range, and the several various earthquakes were applied to the cabinet to verify the control performance of the tuned mass damper. After analyzing the numerical results, it is summarized that the application of the proposed technique can reduce the acceleration response of the cabinet.
ARTICLE | doi:10.20944/preprints201909.0202.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Plants-Microbial Fuel Cells; clean energy; electric potential; power output; resistivity
Online: 18 September 2019 (08:21:05 CEST)
Plants Microbial Fuel Cells (PMFC) is a new technology that generates electricity in a renewable, clean and sustainable way. In spite of these advantages, it still faces limitations in power generation and current density, reaching lower production values than other renewable technologies. Different studies maintain that the high resistivity of the cathode is the main limitation in the generation of energy; therefore, non-metallic materials to obtain a better performance are replacing the metallic electrodes. The implementation of these materials applied to PMFC requires a complex interdisciplinary work. Through three experimental tests using metallic electrodes for the extraction of electrons, this research study shows that the treatment of the substrate with natural materials, the volume plant roots, and substrate temperature and humidity control have a significant influence in the increase of the electric potential and the generated current.
ARTICLE | doi:10.20944/preprints201901.0214.v1
Subject: Engineering, Automotive Engineering Keywords: Smart city; energy management; electric vehicle; classification; state of charge; intelligence.
Online: 22 January 2019 (11:18:42 CET)
Smart cities and smart technologies have been incorporated into several axes to increase the comfort of life. The connected building's concept was introduced for this reason. However, it was utilized in power management for better organizing, greater buildings management, and monetary savings. Cars technologies and the number of vehicles are also involved; Nowadays, each house has at least one car. Technological evolution helped to make those cars intelligent and connected. In the latest versions, the majority of those cars were equipped with several sensors, several communication protocols and a principal electrical control unit (ECU), especially for the electric vehicle model. This type of architecture was an essential element in a smart city, thus, it helps to manage power and decide when a vehicle needs to be charged. Based on the smart city concept and using possible network communication between buildings and vehicles, EVs can share their own information related to the powerful experience on a specific path. This information can be gathered in a gigantic database and used for managing the power inside these vehicles. In this field, we propose in this paper a new approach for power management inside an electric vehicle based on bi-communication between vehicles and buildings. The proposed approach is founded on two essential parts; the first is related to vehicles’ classification and buildings’ recommendation according to different car positions. Two algorithms, related to the SVC and neural network was employed in this work for implementing the final process. Different possibilities and situations were discussed for this approach. The proposed method was tested and validated using Simulink/Matlab application. The state of charge of the used battery was compared at the end of this work, for two specified cases, for showing the contribution of this approach.
ARTICLE | doi:10.3390/sci1010003.v1
Subject: Keywords: hybrid energy storage; energy efficiency; frequency domain analysis; hybrid electric vehicles
Online: 1 November 2018 (00:00:00 CET)
In Electrified Vehicles, the cost, efficiency, and durability of electrified vehicles are dependent on the energy storage system (ESS) components, configuration and its performance. This paper, pursuing a minimal size tactic, describes a methodology for quantitatively and qualitatively investigating the impacts of a full bandwidth load on the ESS in the HEV. However, the methodology can be extended to other electrified vehicles. The full bandwidth load, up to the operating frequency of the electric motor drive (20 kHz), is empirically measured which includes a frequency range beyond the usually covered frequency range by published standard drive cycles (up to 0.5 Hz). The higher frequency band is shown to be more efficiently covered by a Hybrid Energy Storage System (HESS) which in this paper is defined as combination of a high energy density battery, an Ultra-Capacitor (UC), an electrolytic capacitor, and a film capacitor. In this paper, the harmonic and dc currents and voltages are measured through two precision methods and then the results are used to discuss about overall HEV efficiency and durability. More importantly, the impact of the addition of high-band energy storage devices in reduction of power loss during transient events is disclosed through precision measurement based methodology.
ARTICLE | doi:10.20944/preprints201807.0385.v2
Subject: Social Sciences, Other Keywords: low carbon island; electric motorcycles; green transport; battery exchange; carbon emissions
Online: 5 September 2018 (16:23:53 CEST)
Global warming and climate change have led to extreme changes in climatic conditions in recent years. The Taiwan government designates the construction of the Kinmen County as low carbon islands, to promote the operation of 100 electric motorcycles and battery demonstration. This study combined with island tourism, after boarding the island, visitors can rent electric motorcycles from the passenger service center and coordinate with the island tour map to show the location of the battery exchange points, so as to facilitate the search. During the operation, the amount of electric motorcycle lease is 15,551 times, the total mileage of motor vehicle is 284,404 km, the number of battery exchange is 622 times, the lease income is about NT$900,000. To reduce carbon and economic benefits of the assessment, compared to the motorcycles (50 c.c), electric motorcycles (EM 100) can reduce the carbon emissions by 8,726 kg, reducing energy costs of NT$422,594.
ARTICLE | doi:10.20944/preprints201803.0122.v1
Subject: Engineering, Energy & Fuel Technology Keywords: electric vehicle; Nissan Leaf; lithium-ion battery; capacity loss; battery degradation
Online: 15 March 2018 (07:19:52 CET)
Analysis of 1382 measures of battery State of Health (SoH) from 283 Nissan Leafs (“Leaf/s”), manufactured between 2011 and 2017, has detected a faster rate of decline in this measure of energy-holding capacity for 30 kWh variants. At two years of age, the mean rate of decline of SoH of 30 kWh Leafs was 9.9% per annum (95% uncertainty interval of 8.7% to 11.1%; n = 82). This was around three times the rate of decline of 24 kWh Leafs which at two years averaged 3.1% per annum (95% uncertainty interval of 2.9% to 3.3%; n = 201). For both variants there was evidence for an increasing rate of decline as they aged, although this was much more pronounced in the 30 kWh Leafs. Higher use of rapid DC charging was associated with a small decrease in SoH. Additionally, while 24 kWh cars with greater distances travelled showed a higher SoH, in 30 kWh cars there was a reduction in SoH observed in cars that had travelled further. The 30 kWh Leafs sourced from United Kingdom showed slower initial decline than those from Japan, but the rate of decline was similar at two years of age. Improvements in the battery health diagnostics, continuous monitoring of battery temperatures and state of charge, and verification of a fundamental model of battery health are needed before causes and remedies for the observed decline can be pinpointed. If the high rate of decline in battery capacity that we observed in the first 2.3 years of a 30 kWh Leaf’s lifetime were to continue, the financial and environmental benefits of this model may be significantly eroded. Despite 30 kWh Leafs accounting for only 14% of all light battery electric vehicles registered for use on New Zealand roads at the end of February 2018, there is also the potential for the relatively poor performance of this specific model to undermine electric vehicle uptake more generally unless remedies can be found.
ARTICLE | doi:10.20944/preprints201705.0033.v1
Subject: Engineering, Mechanical Engineering Keywords: electric vehicle; solar power; techno-economic analysis; carbon emission mitigation; India
Online: 4 May 2017 (06:22:04 CEST)
The technologies influencing alternative ways of transportation are augmenting in recent years as the need for transportation is increasing rapidly due to urbanization and motorization. In this paper, a solar powered electric auto-rickshaw (SPEA) is designed and developed for Indian conditions. The developed vehicle is comprehensively analyzed techno-economically for its viability in the Indian market. The performance analysis of SPEA results in an optimal charging rate of 2 kWh per day with an average solar irradiance of 325 W/m2. The discharging characteristics are studied based on different loading conditions. The vehicle achieved a maximum speed of 21.69 km/h with battery discharge rate of 296W at 90kg load and also reached a maximum discharge rate of 540W at 390kg loading with a maximum speed of 12.11 km/h. The environmental analysis of SPEA displayed yearly CO2 emissions of 1,777 kg, 1,987 kg and 1,938 kg using Compressed Natural Gas, Liquefied Petroleum Gas and gasoline engines respectively can be mitigated using SPEA. The results of financial analysis of SPEA were welcoming as the investor gets 24.44% lesser payback duration compared to gasoline run vehicle. Socio-Economic analysis of SPEA discussed its significant advantages and showed 18.73% and 3.9% increase in yearly income over gasoline driven and battery driven vehicles.
ARTICLE | doi:10.20944/preprints202209.0386.v1
Subject: Social Sciences, Other Keywords: micromobility; sustainable transport; electric vehicles; active travel; LEV; so-cio-technical analysis
Online: 26 September 2022 (08:51:42 CEST)
While micromobility has seen a significant rise of interest across policy, industry and academia, a detailed conceptualisation of it has so far been missing from the scientific literature. This paper develops a multi-dimensional conceptualisation of micromobility, in conjunction with a new socio-technical definition. To do so, it reviews related concepts; it analyses how the term micromobility has been used; and it critically engages with existing definitions most frequently cited in this literature. Building on these insights, we develop a multi-dimensional conceptualization of micromobility. Our definition of micromobility covers a wide range of mobility options that can typically be manoeuvred by one human without motor assistance, at least for short distances, and that are ‘micro’ in terms of energy demand, environmental impact, and use of road space, relative to automobility. According to our conceptualisation, micromobility modes comprise fully human powered, partially motor assisted and fully powered options. They typically do not exceed 25 kilometres per hour (or 45 for faster ones) and weigh (often significantly) less than 350 kilogram, while often providing some (public) health benefits. Trip lengths are typically less than 15 kilometres and daily distance travelled less than 80 kilometres. This new definition has relevance for future transport and mobility scholarship, as well as policy and evaluation. Advantages of a new and widely accepted definition and conceptualisation of micromobility could include more robust design standards, legislation, as well as evaluation metrics and methods, all leading to greater understanding of, and attention paid to, this form of mobility. This paper highlights the important role that micromobilities could play in moving beyond automobility, to create more sustainable and just mobility futures.
ARTICLE | doi:10.20944/preprints202112.0326.v1
Subject: Earth Sciences, Environmental Sciences Keywords: air pollution; transportation policy; vehicle fleet projections; electric vehicles; exponential smoothing; Greece
Online: 21 December 2021 (12:26:52 CET)
This study provides a thorough review and analysis of the evolution of the Greek vehicle fleet over the last ~30 years, which is next used for the generation of high granularity fleet projections and for the estimation of relevant environmental benefits by 2030. The integrated methodology developed takes also into account vehicle clustering and the Brown’s Double Simple Exponential Smoothing technique that together with the adoption of COPERT based emission factors allow for the estimation of the anticipated emissions in 2030. Expected 2030 emissions levels suggest a reduction across all pollutants in comparison to 2018, ranging from 3.7% for PM10 to 54.5% for NMVOC (and 46% for CO, 14% for SO2, 28% for NOX and 21% for CO2). We find that Greece is on track with national goals concerning the reduction of air pollution from the transportation sector, stressing the positive contribution of EVs and new, "greener" vehicles, and setting new challenges for the further improvement of the sector beyond the 2030 outlook.
ARTICLE | doi:10.20944/preprints202110.0418.v1
Subject: Engineering, Civil Engineering Keywords: Direct electric curing; Steam curing; Mechanical properties; Microstructure; Joule heat; Energy consumption
Online: 27 October 2021 (14:25:44 CEST)
Direct electric curing (EC) is a new green curing method for cement-based materials that improves the early mechanical properties via the uniform high temperature produced by Joule heating. To understand the effects of EC and steam curing (SC) on the mechanical properties and microstructure of cement-based materials, the mortar was cured at different temperature-controlled curing regimes (40°C, 60°C and 80°C). Meanwhile, mechanical properties, hydrate phase and pore structure of specimens were investigated. The energy consumption of two curing methods was compared and analyzed. The results show that the EC specimens have better and more stable growth of mechanical strength. The pore structure of EC specimen is also better than that of SC specimen at different maintenance ages. However, the hydration degree and products of samples cured by EC are similar to that SC samples. The energy consumption of EC is lower than SC. This study provides an important technical support for the EC in the production of energy-saving and high early-strength concrete precast components.
ARTICLE | doi:10.20944/preprints202101.0542.v1
Subject: Engineering, Automotive Engineering Keywords: Automotive Engineering, Electric Bus, CFD, Numerical Fluid Mechanics, Electromobility, Noise, Eco-Design
Online: 26 January 2021 (15:23:24 CET)
The dynamic development of electromobility poses challenges to designers regarding not only the efficiency of energy transformation but also the battery life, which is influenced by the stability of its operating temperature. Designing cooling systems is connected not only with the optimization of energy management but also with other environmental parameters, such as noise emission. The paper presents the numerical optimization of an innovative radiator for use in electric buses in terms of energy consumption and noise emission. The results of the numerical studies were verified in laboratory and field conditions, showing a very good convergence of the model with the results of the experiments.
Subject: Engineering, Electrical & Electronic Engineering Keywords: Computational electromagnetics; Electric Vehicle; EMF safety; low frequency dosimetry; Wireless Power Transfer
Online: 11 January 2021 (15:55:44 CET)
In this study, the external magnetic field emitted by a wireless power transfer (WPT) system and the internal electric field induced into human body models during recharging operations of a compact electric vehicle (EV) are evaluated. To this aim an ad-hoc formulation for the source modeling is coupled with a commercial software that performs numerical dosimetry. Specifically, two realistic anatomical models both in a driving position and in a standing posture are considered, and the chassis of the EV is modeled either as a currently employed aluminum alloys and as a futuristic carbon fiber composite panel. Aligned and misaligned coil configurations of the WPT system are considered as well. The analysis of the obtained results shows that the ICNIRP reference levels are exceeded in the driving position, especially for the carbon fiber chassis, whereas no exceedance is observed in terms of basic restrictions, at least for the considered scenarios.
ARTICLE | doi:10.20944/preprints201804.0135.v1
Subject: Engineering, Energy & Fuel Technology Keywords: electric vehicles; fuel cell vehicles; sustainable mobility; mobility habits; sustainable urban transportation
Online: 11 April 2018 (05:29:14 CEST)
As the emission regulations get more and more stringent in the different fields of energy and environmental systems, the electric and fuel cell vehicles (FCV) have attracted growing attention by automakers, governments, and customers. Research and development efforts have been focused on devising novel concepts, low-cost systems, and reliable electric/fuel cell powertrain. In fact, electric and fuel cell vehicles coupled with low-carbon electricity sources offer the potential for reducing greenhouse gas emissions and exposure to tailpipe emissions from personal transportation. In particular, Pedal Assisted Bicycles (PAB) popularity is rising in urban areas due to their low energy consumption and environmental impact. In fact, when electrically moved, they are zero emission vehicles with very low noise emissions, as well. These positive characteristics could be even improved by coupling a PAB with a fuel cell based power generation system, thus increasing the vehicle autonomy without influencing their emissions and consumption performances. In this paper, four types of vehicles are compared from an environmental and accessibility point of view: conventional car, bus, electric PAB and hydrogen fuel cell PAB; for such vehicles, the respective utilization stages are accounted for, i.e. without considering the manufacturing process. The analysis has been carried out comparing different vehicles performance along different routes of an Italian middle-size city, Viterbo, which represents a very good pilot case as its Municipality is adopting many solutions suggested by European Union (EU) through the planning tool called Sustainable Energy Action Plan (SEAP). The comparison is based on an ad-hoc developed mathematical procedure, which includes environmental (greenhouse gas and air pollution emissions), health (pollutants toxicity levels) and accessibility time (waiting times) indicators. According to this analysis, electric and fuel cell PAB exhibit interesting advantages over the other vehicles. However, the global economic efficiency of electric or fuel cell apparatus depends substantially on the exploited source of electrical energy.
ARTICLE | doi:10.20944/preprints201712.0046.v1
Subject: Engineering, Energy & Fuel Technology Keywords: DSC; DSM; BIPV; buildings; photovoltaic; thermal properties; electric properties; glazing; energy efficiency
Online: 7 December 2017 (15:12:19 CET)
Dye sensitized solar cell technology is having an important role in renewable energy research due to its features and low cost manufacturing processes. Devices based on this technology appear very well suited for integration into glazing systems due to their characteristics of transparency, color tuning and manufacturing directly on glass substrates. Field data of thermal and electrical characteristics of dye sensitized solar modules (DSM) are important since they can be used as input of building simulation models for the evaluation of their energy saving potential when integrated into buildings. However still few works in the literature provide this information. The study here presented wants to contribute to fill this gap providing a thermal and electrical characterization of a DSM in real operating conditions using a method developed in house. This method uses experimental data coming from test boxes exposed outdoor and dynamic simulation to provide thermal transmittance and solar heat gain coefficient (SHGC) of a DSM prototype. The device exhibits an U-value of 3.6 W/m2K, confirmed by an additional measurement carried on in the lab using a heat flux meter, and a SHGC of 0.2, value compliant with literature results. Electrical characterization evidences an increase of module power with respect to temperature causing DSM suitable for integration in building facades.
ARTICLE | doi:10.20944/preprints201710.0028.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Integrated Electric Power and Natural Gas Network, Optimal Power Flow, Genetic Algorithm.
Online: 5 October 2017 (09:41:12 CEST)
This paper proposes a method based on genetic algorithm (GA) for the security-constrained optimal dispatch of integrated natural gas and electricity networks, considering operating scenarios in both energy systems. The mathematical formulation of the optimization problem consists of a multi-objective function which aims to minimize both cost of thermal generation (diesel and natural gas) as well as the production and transportation of natural gas. The joint gas-electricity system is modeled by two separate groups of nonlinear equation, which are solved by the combination of Newton's method with the GA. The applicability of the proposed method is tested in the Belgian gas network integrated with the IEEE 14-bus test system and a 15-node natural gas network integrated with the IEEE 118-bus test system. The results demonstrate that the proposed method provides efficient and secure solutions for different operating scenarios in both energy systems.
ARTICLE | doi:10.20944/preprints201611.0015.v1
Subject: Life Sciences, Biophysics Keywords: cardiac transmural heterogeneity; electromechanical coupling; mechano-calcium-electric feedback; cardiac modeling; cardiomyocyte
Online: 2 November 2016 (06:58:53 CET)
Myocardial heterogeneity is an attribute of the normal heart. We have developed integrative models of cardiomyocytes from the subendocardial (ENDO) and subepicardial (EPI) ventricular regions that take into account experimental data on specific features of intracellular electromechanical coupling in the guinea pig heart. The models adequately simulate experimental data on the action potential and contraction of the ENDO and EPI cells. The modeling results predict that heterogeneity in the parameters of calcium handling and myofilament mechanics in isolated ENDO and EPI cardiomyocytes via cooperative mechanisms of mechano-calcium-electric feedback are essential to produce the differences in Ca2+ transients and contraction profiles and may further enhance transmural differences in the electrical properties between the cells. Simulation results predict that ENDO cells have greater sensitivity to changes in afterload than EPI cells. These data are important for understanding the behavior of cardiomyocytes in the intact heart.
COMMUNICATION | doi:10.20944/preprints202209.0396.v1
Subject: Physical Sciences, General & Theoretical Physics Keywords: foundations of physics; electrodynamics; electromagnetic wave; magnetic field; electric field; Ampere; Biot-Savart
Online: 26 September 2022 (11:04:47 CEST)
The well-known coupling between the magnetic and electric fields in electromagnetic radiation is revisited in light of the recent introduction of a microscopic theory for the Ørsted magnetic field induction. I argue that, if the Ørsted magnetic field induction does indeed have a microscopic origin rather than the continuum solution offered by the Maxwell-Ampere equation, the "electromagnetic wave"' propagating in vacuum will not have a magnetic component.
ARTICLE | doi:10.20944/preprints202205.0337.v1
Subject: Engineering, Mechanical Engineering Keywords: e-VTOL vehicles; coaxial rotors; design optimization; operation; experiments; electric propulsion; propeller pitch
Online: 25 May 2022 (03:34:42 CEST)
Coaxial rotors can be found in multirotor vehicles for the added thrust compared to independent rotors while keeping similar area footprints but, performance losses should be considered. This experimental study analyzes the effects of varying motor throttle and propeller pitch values in motor-propeller systems with two to four coaxial rotors. The results show that in a two-rotor coaxial system, to lessen the adverse effects of a front rotor’s backwash and to operate at the maximum performance, only the back motor should be operated initially up to 75% duty cycle before using the front motor up to its 75% duty cycle. Additional thrust requirements should be generated from the back rotor and then from the front rotor up to their maximum duty cycles. In two, three, and four-rotor coaxial setups, total thrust output generated is 1.6, 2.1, and 2.5 times the thrust output at system thrust performance of 86%, 76%, and 66%, respectively of that of an isolated rotor. In a four-rotor coaxial setup, maximum system performance is achieved when the propeller pitch values are gradually increased from the first to the last rotor. The gradual increments in propeller pitch values also result in more uniform thrust sharing among rotors.
ARTICLE | doi:10.20944/preprints202107.0322.v3
Subject: Physical Sciences, Condensed Matter Physics Keywords: fluctuations; noise spectra; longitudinal and transverse electric fields; Nyquist noise; photon number noise
Online: 17 January 2022 (09:04:34 CET)
We derive the thermal noise spectrum of the Fourier transform of the electric field operator of a given wave vector starting from the quantum-statistical definitions and relate it to the complex frequency and wave vector dependent complex conductivity in a homogeneous, isotropic system of electromagnetic interacting electrons. We analyze separately the longitudinal and transverse case with their peculiarities. The Nyquist formula for vanishing frequency and wave vector, as well as its modification for non-vanishing frequencies and wave vectors follow immediately. Furthermore we discuss also the noise of the photon occupation numbers. It is important to stress that no additional assumptions at all were used in this straightforward proof.
REVIEW | doi:10.20944/preprints202107.0098.v1
Subject: Engineering, Automotive Engineering Keywords: servovalves, piezo-electric actuators, piezo-stacks, amplified piezo-stacks, rectangular benders, ring benders.
Online: 5 July 2021 (12:33:44 CEST)
This paper is a thorough review of innovative architectures of electro-hydraulic servovalves that exploit actuation systems based on piezo-electric materials. The use of commercially available piezo-electric actuators, namely, piezo-stacks, amplified piezo-stacks, rectangular benders and ring benders, is very promising for the actuation of the main stages and of the pilot stages of servovalves, given the fast response and low weight of piezoelectric materials. The use of these actuators can also allow novel designs to be developed, thus helping manufacturers to overcome the typical drawbacks of commercial servovalves, such as the high complexity and the high internal leakage of the pilot stages of two stage servovalves, as well as the large size and weight of direct drive servovalves. Firstly, the piezoelectric actuators that can be used for driving servovalves are presented in the paper and their characteristics are thoroughly discussed. Then, the main novel architectures present in the literature are explained and compared with the commercial ones, and their performance parameters are discussed to draw conclusions on the prospect that some of these architectures can be used by manufacturers as future designs.
Subject: Keywords: membrane potential, constant electric field , resting potential, action potentia, GHK eq., HH model
Online: 22 June 2021 (16:03:03 CEST)
An embryonic version of membrane theory can be date back to the Bernstein's work reported more than a hundred years ago. Such an originally old work has evolved conceptually and mathematically up until today, and it plays a central role in current membrane theory. Goldman-Hodgkin-Katz equation (GHK eq.) is one of the math-based monumental works, which constitutes the present membrane theory. Goldman theoretically derived GHK eq., but its physiological meaning was provided by the two renowned scientists, Hodgkin and Katz. These two employed an assumption that the electric field (EF) across the plasma membrane is constant to validate the GHK eq. physiologically. Proposal of Hodgkin-Huxley model (HH model) is another math-based monumental works developed from the membrane theory and now forms a fundamental part of the current membrane theory. GHK eq. and HH model are quite fundamental central concepts in the current physiology. Despite the broad acceptance of GHK eq. at present time, its prerequisite that the EF within the plasma membrane is constant is hardly believable. Especially when the action potential is generated, it sounds totally nonsense. Furthermore, the existence of constant EF within the plasma membrane is conceptually almost in conflict with the HH model. The authors will discuss those problematic issues the membrane theory inherits.
ARTICLE | doi:10.20944/preprints202101.0401.v1
Subject: Engineering, Automotive Engineering Keywords: Electric arc furnace; Arc short circuit; transient power quality; transient voltage; voltage sag
Online: 20 January 2021 (14:24:47 CET)
Three-phase AC electric arc furnace (EAF) is a typical non-linear load, causing many power quality problems. Most of the researches on the voltage problems of EAF mainly focus on the voltage fluctuation, and less on the transient voltage problems caused by EAF short circuit and open circuit. In this paper, the relationship between voltage and current of EAF is obtained by combining hyperbolic function and exponential function, then the white noise and chaotic circuit are added to establish the EAF model which is suitable for the study of voltage fluctuation and transient voltage. This paper analyzes the causes of the transient voltage problem of the EAF, calculates the short-circuit current, reactive impact and the influence on voltage at the point of common coupling (PCC) in the three-phase short-circuit of the EAF, and compares the calculation results with the simulation results to prove the accuracy of this model. The results show that the reactive impact of three-phase short circuit is about twice as much as that of normal operation of EAF, resulting in about 30% voltage sag at the PCC, which is very unfavorable to the power grid. This paper provides reference for transient power quality evaluation and dynamic reactive power compensation of EAF.
REVIEW | doi:10.20944/preprints202012.0435.v1
Subject: Engineering, Automotive Engineering Keywords: Electric Vehicles; Greenhouse Gas; Climate Change; Transportation; Energy; Renewables; Lifecycle Assessment; Electricity Grid
Online: 17 December 2020 (15:52:28 CET)
An indisputable fact about our planet is that its atmospheric temperature has risen dramatically during the past century. Combustion of fossil fuels and their subsequent greenhouse gas emissions are thought to be the main contributors to recent changes within the Earth’s ecosystem. The transportation sector and electricity generating power plants are each responsible for approximately one-third of these emissions. Shifting towards a cleaner and renewable resources to generate electricity is believed to omit a big portion of polluting substances. Improvements in vehicles’ fuel efficiency and the introduction of alternative fuels besides strategic plans to control travel demand are among the most promising approaches to alleviate emissions from the transportation sector. Recent technology advancements, however, drew much attention to the production and manufacturing of alternative fuel vehicles, electric vehicles in particular. Since these vehicles use electricity as part of or all their powertrain, assessing the amount of emissions they produce is closely tied to the cleanliness of the electricity source. In order for a valid comparison to be made between internal combustion and electric vehicles, hence, a life cycle assessment procedure needs to be followed from production stages to terminal life of vehicles. Involvement of numerous affecting factors during the lifetime of a vehicle on one hand, and the ambiguity in the exact source of electricity used to charge electric vehicles on the other hand bring about more complexities. The latter case is more commonly known as the marginal grid problem, which deals with how a combination of sources used to generate electricity can influence the life cycle emissions. There are also other concerns regarding the growth in fuel-efficient and electric vehicles. Transportation planners argue that new developments in the vehicle industry may attract more people to owning and driving cars. This phenomenon which is better known as a rebound effect not only will result in increased traffic congestion, but it can also outpace the environmental benefits from utilizing electric vehicles. Moreover, since fuel taxes comprise the majority of Highway Trust Funds, alternative ways to compensate for state and federal revenues should be devised. This paper is an attempt to review the existing literature to better elaborate on the role of the transportation sector in controlling climate change threats. More specifically, issues around the use of electric vehicles and how they can contribute to more environmentally friendly communities are discussed.
ARTICLE | doi:10.20944/preprints202011.0592.v1
Subject: Engineering, Automotive Engineering Keywords: asynchronous electric motor; frequency control; vector control; vector equation; nonlinear transfer functions; experiment
Online: 23 November 2020 (14:45:05 CET)
Abstract: The article proposes to consider the possibility of connecting the problems of engineering synthesis of frequency control systems for asynchronous electric drives with the basic provisions of the theory of identification of asynchronous electric motors based on the equations of a generalized AC electric machine.The article presents the results of experimental studies of load parrying processes in asynchronous electric drives with vector and scalar controls. These results indicate the absence of fundamental advantages as processes in a drive with vector control. This advantage should have manifested itself in a more efficient formation of the moment and fast transients. It is suggested that the reason for this is in too significant errors, assumptions and simplifications of the equations adopted in the derivation of vector control and which are its theoretical basis. A method is proposed for describing asynchronous electric motors by nonlinear transfer functions, which made it possible to formulate the principle of correction of electric drives and a method for assessing their efficiency.The article shows. that the correction based on the proposed nonlinear transfer functions of the induction motor is much more efficient than the traditional vector control, which was confirmed by detailed experiments and modeling. The results of the most important of which are given in the article. An assumption was made. that the advantage in efficiency is due to a more accurate identification of the dynamics of an asynchronous electric motor with a gear function instead of vector equations.
ARTICLE | doi:10.20944/preprints201905.0331.v1
Subject: Engineering, Energy & Fuel Technology Keywords: large-scale RES; curtailments; electric vehicles; EnergyPLAN; integrated energy systems analysis; CO2 emissions
Online: 28 May 2019 (10:33:27 CEST)
Electric vehicles, being able to reduce pollutant and greenhouse gas emissions and shift the economy away from oil products, can play a major role in the transition towards low-carbon energy systems. However, the related increase in electricity demand inevitably affects the strategic planning of the overall energy system as well as the definition of the optimal power generation mix. With this respect, the impact of electric vehicles may vary significantly depending on the composition of both total primary energy supply and electricity generation. In this study, Italy and Germany are compared to highlight how a similarity in their renewable shares not necessarily leads to a CO2 emissions reduction. Different energy scenarios are simulated with the help of EnergyPLAN software assuming a progressive increase in renewable energy sources capacity and electric vehicles penetration. Results show that, for the German case, the additional electricity required leads to a reduction in CO2 emissions only if renewable capacity increases significantly, whereas the Italian energy system benefits from transport electrification even at low renewable capacity. Smart charging strategies are also found to foster renewable integration; however, power curtailments are still significant at high renewable capacity in the absence of large-scale energy storage systems.
ARTICLE | doi:10.20944/preprints201808.0391.v1
Subject: Engineering, Mechanical Engineering Keywords: full electric aircraft; hybrid aircraft; energy and mass balance equations; conceptual design; constraints
Online: 22 August 2018 (05:13:14 CEST)
Nowadays, all the stakeholders, policy makers, regulators, aircraft designers, producers, operators, etc.) are intensively working on development of the aircraft with full electric and hybrid propulsion systems. However, the technical, technological constrains (like limit on accumulator energy density) require introducing a new approach to conceptual design of such aircraft. The new methods is based on energy and mass balance evaluation. This paper analyses the identified constrains; integrates the energy and mass balance equations into the preliminary definition and calculations of the aircraft performance. By this way, the technological constrains might be transferred into the limitation on the aircraft energy and mass breakdown, that initiates a new approach to aircraft conceptual design uses the knowledge based multidisciplinary optimization. The paper describes the developed methodology for conceptual design of aircraft. It show results of implementing this new development philosophy to conceptual design of a four-seat small electric/hybrid aircraft and a special hybrid cargo UAV. The discussion of the results including got by using the emerging and enabling new technologies and new methods and solutions (including for example distributed propulsion system, unconventional forms, morphing, biomimics, etc.), demonstrates the possible implementation of the new development philosophy, new approach to aircraft conceptual design.
ARTICLE | doi:10.20944/preprints201807.0442.v1
Subject: Engineering, Mechanical Engineering Keywords: electric vehicles; configuration synthesis; motor transmission; in-wheel-hub motor; six-link mechanism
Online: 24 July 2018 (05:59:20 CEST)
Nowadays, there are several electric vehicle (EV) on the market, due to the innovation of technology that promotes the new components such as battery, transmission, electric motors. This paper proposes a design approach for the configuration synthesis and simulation of the in-wheel-hub motor transmissions with the six-link mechanisms. The synthesis process shows 6 mechanisms with six members and eight joints, 15 new clutchless motor transmissions and 16 new clutched motor transmissions. A novel motor transmission in the feasibility of the synthesized configurations is selected as an example to analyze the working principle with operation modes and power flow paths. And, this design is modeled for the simulation process that generates the results of operation mode transition and energy regulation.
ARTICLE | doi:10.20944/preprints201805.0390.v1
Subject: Engineering, Energy & Fuel Technology Keywords: low carbon fuel standard; electric vehicles; policy analysis; electricity market; agent based modelling
Online: 28 May 2018 (08:56:01 CEST)
Electric Vehicles (EVs) are increasing the interdependence of transportation policies and the electricity market. EMMEV (Electricity Market Model with Electric Vehicles) is an experimental agent-based model that analyses how carbon reduction policy in transportation may increase number of Electric Vehicles and how does that would influence on the electricity price. Agents are ESCOs (Energy Service Providers) which can distribute fuels and their objective is to maximize their profit. In this paper, EMMEV is used to analyze the impacts of the LCFS (Low Carbon Fuel Standard), a performance-based policy instrument, on electricity prices and EV sales. The agents in EMMEV/regulated parties in LCFS should meet a certain CI (Carbon Intensity) target for their distributed fuel. In case, they cannot meet the target, they should buy credit to compensate for their shortfall and if they exceed, they can sell their excess. The results, considering the assumptions and limitations of the model, show that the banking strategy of the agents contributing in the LCFS might have negative impact on penetration of EVs, unless there is a regular Credit Clearance to trade credits. It is also shown that the electricity price as result of implementing the LCFS and increasing number of EVs has increased between 2–3 percent depending on banking strategy.
ARTICLE | doi:10.20944/preprints201610.0006.v1
Subject: Materials Science, Other Keywords: steel slag; electric arc furnace slag; magnetite; radiation shielding concrete; concrete; EAF; aggregate
Online: 4 October 2016 (09:28:42 CEST)
Electric arc furnace oxidizing slag (EAF) has a high density of 3.0~3.7 t/m3 and therefore has a high bulk density when mixed with concrete. Extensive research has been conducted on the use of concrete with high unit volume weight as heavyweight concrete for radiation shielding concrete. In this study, to examine the possibility of developing a radiation shielding concrete, the physical properties of normal concrete, magnetite concrete, EAF concrete, and EAF concrete with added iron powder, were compared. Also, their radiation shielding performance was assessed through shielding tests against X-rays and γ-rays. While the unit volume weight of EAF concrete (3.21 t/m3) appeared lower than that of magnetite concrete (3.5 t/m3), the compressive strength of EAF concrete was greater than those of magnetite and normal concretes. The radiation shielding ratio of magnetite concrete was observed to be 93.9% from the X-ray shielding test, followed by 91.2% of EAF concrete, and 73.7% of normal concrete, indicating a linear relationship with unit volume weight. From the γ-ray shielding test, the performance of EAF and magnetite concretes appeared to be similar. Based on the excellent physical properties and radiation shielding performance of EAF concrete, its potential applicability as radiation shielding concrete was confirmed.
ARTICLE | doi:10.20944/preprints202202.0293.v1
Subject: Physical Sciences, General & Theoretical Physics Keywords: Special relativity; General relativity; Electromagnetism; Bending of electric field lines in a gravitational field; Electric field lines of a freely falling charge; Bending of photon trajectories in a gravitational field
Online: 23 February 2022 (12:58:14 CET)
It is well known that the photon trajectories follow a curved path in a gravitational field. We explore here the gravitational bending of electric field lines. It seems that the electric field lines of a charge, supported in a gravitational field, follow exactly the trajectories of photons emitted isotropically from a source situated at the charge location. From a detailed examination of the electrostatic field of a charge accelerated uniformly in the instantaneous rest frame, exploiting the strong principle of equivalence, one can determine the bending of the electric field lines of a charge in a gravitational field. The fraction of electric field lines crossing a surface, stationary above or below the charge in the gravitational field, is shown to be exactly similar to the fraction of photon trajectories, emitted from a source placed at the charge location, intersecting that surface. On the other hand, for a freely falling charge in the gravitational field there is no such bending of electric field lines. The field lines continue to extend in radial straight lines from the instantaneous 'present' position of the charge, as do the trajectories of photons streaming away from the instantaneous position of a freely falling source in the gravitational field. The electric field configuration of a freely falling charge in the gravitational field is shown to be exactly the same as that of a charge moving uniformly in an inertial frame with velocity equal to the instantaneous ``present'' velocity of the freely falling charge.
ARTICLE | doi:10.20944/preprints202201.0180.v1
Subject: Materials Science, Nanotechnology Keywords: ion-exchange membrane; electric conductivity; diffusion permeability; permselectivity; structure–properties relationship; modification; microheterogeneous model
Online: 12 January 2022 (17:53:23 CET)
Ion-exchange membranes (IEMs) are widely used in desalination, waste water treatment, food, energy production and other applications. There is a strong demand for cost-effective IEMs characterized by high selective transport of ions of a certain sign of charge. In this paper, we simulate the experimental results of V. Sarapulova et al. (IJMS 2021) on the modification of an inexpensive anion-exchange membrane (CJMA-7, Hefei Chemjoy Polymer Materials Co. Ltd., China) with a perfluorosulfonated ionomer (PFSI). The modification was made in several stages including keeping the membrane at a low temperature, applying a PFSI solution on its surface, and subsequent drying it at an elevated temperature. We apply the known microheterogeneous model with some new amendments to simulate each stage of the membrane modification. It has been shown that the PFSI film formed on the membrane-substrate does not affect significantly its properties due to the small thickness of the film (4 m) and similar properties of the film and substrate. The main effect is caused by the fact that PFSI material “clogs” the macropores of the CJMA-7 membrane, thereby blocking the transport of coions through the membrane. In this case, the membrane microporous gel phase, which has a high selectivity to counterions, remains the primary pathway for both counterions and coions. Due to the above modification of the CJMA-7 membrane, the coion (Na+) transport number in the membrane equilibrated with 1 M NaCl solution decreased from 0.11 to 0.03. Thus, the modified membrane becomes comparable in its transport characteristics with more expensive IEMs available on the market.
BRIEF REPORT | doi:10.20944/preprints202111.0081.v1
Subject: Earth Sciences, Atmospheric Science Keywords: electric streamer discharges; streamer theory; streamer parameters; plasma instabilities; partially-ionized plasmas; atmospheric electricity
Online: 3 November 2021 (13:59:43 CET)
Electric streamer discharges (streamers) in air are a very important stage of lightning, taking place before formation of the leader discharge, and with which an electric discharge starts from conducting objects which enhance the background elecric field, such as airplanes. Despite years of research, it is still not well understood what mechanism determines the values of streamer parameters, such as its radius and propagation velocity. The Streamer Parameter Model (SPM) is aimed to understand this mechanism, as well as to provide a way to efficiently calculate streamer parameters. Previously, we demonstrated that SPM results compared well with a limited set of experimental data. In this Brief Report, we compare SPM predictions to the published hydrodynamic simulation (HDS) results.
ARTICLE | doi:10.20944/preprints202109.0442.v1
Subject: Engineering, Energy & Fuel Technology Keywords: active electric distribution networks; phase load balancing; coordinated control; smart switching devices; end-users
Online: 27 September 2021 (10:22:56 CEST)
In the paper, a coordinated control methodology of single-phase (1-P) end-users switching oper-ations on the phases of an active electric distribution network (AEDN) has been proposed to ob-tain a minimum unbalance degree at the coupling common point (CCP) level with the main dis-tribution system. The phase load balancing (PLB) process considers the smart devices that switch from one phase to another phase the 1-P end-users (consumers and prosumers) to compensate for the phase load unbalance. The proposed methodology has been tested successfully in an AEDN belonging to a Romanian Distribution Network Operator (DNO) containing 114 end-users (104 consumers/10 prosumers) integrated into the Smart Metering System (SMS). The op-timal solution leads to a value of the objective function by 1.00004, represented by the unbalance factor, very close to the ideal target, 1.00. A comparative analysis was conducted considering other possible PLB cases (the consumer-level PLB and prosumer-level PLB), obtaining similar values of the UF (1.027 vs. 1.028), slightly higher than in the hybrid-level PLB. Also, the signifi-cant technical benefits were quantified through an energy-saving of 58.73% and decreasing the phase voltage unbalance rate by 91 % compared to the initial case (without PLB). These results emphasized the positive impact of the proposed coordinated control methodology on the PLB process and evidenced its effectiveness and applicability in the AEDNs.