Range Of Kilometers Research Articles

Development of a PMSM motor field-oriented control algorithm for electrical vehicles

Recently, with issues such as global warming, melting of glaciers and climate change, the need for sustainable methods of living has seen a drastic increase. Combustion cars that run on petrol and diesel are slowly being replaced with electrical vehicles (EVs). Currently, EVs face challenges in terms of range of kilometers offered, availability of charging systems, infrastructure for their development, etc. As the need for electrical vehicles increase, the usages of Permanent Magnet Synchronous Motor (PMSM) too have seen a growing trend. Motor control in an electrical vehicle is extremely crucial as a vehicle on road is subject to different terrains and hence, different loads. Throughout all these different scenarios, it is essential that the motor operates at its optimum efficiency in order to provide optimum vehicle performance for the driver and passengers. Currently, several methods are available for the control of electrical vehicles, nevertheless the field-oriented control (FOC) method for permanent magnet motors is widely used due to its efficient nature. This paper discusses with the design of modified FOC control algorithm for control the PMSM motor eliminates an initial jerk seen during the starting condition of a motor thereby providing a smoother start. As the entire simulation is done using Hardware in the Loop model, the values obtained have real life constraints taken into account, as opposed to a software only simulation. Moreover, the transient time taken to reach a steady state value in speed and to also change direction of rotation have been improved as well. The simulation has been designed entirely on the Altair Embed software.

Detection of Lithium Plating in Li-Ion Cell Anodes Using Realistic Automotive Fast-Charge Profiles

The widespread use of electric vehicles is nowadays limited by the “range anxiety” of the customers. The drivers’ main concerns are related to the kilometric range of the vehicle and to the charging time. An optimized fast-charge profile can help to decrease the charging time, without degrading the cell performance and reducing the cycle life. One of the main reasons for battery capacity fade is linked to the Lithium plating phenomenon. This work investigates two methodologies, i.e., three-electrode cell measurement and internal resistance evolution during charging, for detecting the Lithium plating conditions. From this preliminary analysis, it was possible to develop new Multi-Stage Constant-Current profiles, designed to improve the performance in terms of charging time and cells capacity retention with respect to a reference profile. Four new profiles were tested and compared to a reference. The results coming from the new profiles demonstrate a simultaneous improvement in terms of charging time and cycling life, showing the reliability of the implemented methodology in preventing Lithium plating.

A Flexible Fog Computing Design for Low-Power Consumption and Low Latency Applications

In this paper, we propose a flexible Fog Computing architecture in which the main features are that it allows us to select among two different communication links (WiFi and LoRa) on the fly and offers a low-power solution, thanks to the applied power management strategies at hardware and firmware level. The proposed Fog Computing architecture is formed by sensor nodes and an Internet of Things (IoT) gateway. In the case of LoRa, we have the choice of implementing the LoRaWAN and Application servers on the cloud or on the IoT gateway, avoiding, in this case, to send data to the Cloud. Additionally, we have presented an specific setup and methodology with the aim of measuring the sensor node’s power consumption and making sure there is a fair comparison between the different alternatives among the two selected wireless communication links by varying the duty cycle, the size of the payload, and the Spreading Factor (SF). This research work is in the scope of the STARPORTS Interconnecta Project, where we have deployed two sensor nodes in the offshore platform of PLOCAN, which communicate with the IoT gateway located in the PLOCAN premises. In this case, we have used LoRa communications due to the required large distance between the IoT gateway and the nodes in the offshore platform (in the range of kilometers). This deployment demonstrates that the proposed solution operates in a real environment and that it is a low-power and robust approach since it is sending data to the IoT gateway during more than one year and it continues working.

Solution to the debris disc mass problem: planetesimals are born small?

ABSTRACTDebris belts on the periphery of planetary systems, encompassing the region occupied by planetary orbits, are massive analogues of the Solar system’s Kuiper belt. They are detected by thermal emission of dust released in collisions amongst directly unobservable larger bodies that carry most of the debris disc mass. We estimate the total mass of the discs by extrapolating up the mass of emitting dust with the help of collisional cascade models. The resulting mass of bright debris discs appears to be unrealistically large, exceeding the mass of solids available in the systems at the preceding protoplanetary stage. We discuss this ‘mass problem’ in detail and investigate possible solutions to it. These include uncertainties in the dust opacity and planetesimal strength, variation of the bulk density with size, steepening of the size distribution by damping processes, the role of the unknown ‘collisional age’ of the discs, and dust production in recent giant impacts. While we cannot rule out the possibility that a combination of these might help, we argue that the easiest solution would be to assume that planetesimals in systems with bright debris discs were ‘born small’, with sizes in the kilometre range, especially at large distances from the stars. This conclusion would necessitate revisions to the existing planetesimal formation models, and may have a range of implications for planet formation. We also discuss potential tests to constrain the largest planetesimal sizes and debris disc masses.

Assimilating Visible and Infrared Radiances in Idealized Simulations of Deep Convection

AbstractCloud-affected radiances from geostationary satellite sensors provide the first area-wide observable signal of convection with high spatial resolution in the range of kilometers and high temporal resolution in the range of minutes. However, these observations are not yet assimilated in operational convection-resolving weather prediction models as the rapid, nonlinear evolution of clouds makes the assimilation of related observations very challenging. To address these challenges, we investigate the assimilation of satellite radiances from visible and infrared channels in idealized observing system simulation experiments (OSSEs) for a day with summertime deep convection in central Europe. This constitutes the first study assimilating a combination of all-sky observations from infrared and visible satellite channels, and the experiments provide the opportunity to test various assimilation settings in an environment where the observation forward operator and the numerical model exhibit no systematic errors. The experiments provide insights into appropriate settings for the assimilation of cloud-affected satellite radiances in an ensemble data assimilation system and demonstrate the potential of these observations for convective-scale weather prediction. Both infrared and visible radiances individually lead to an overall forecast improvement, but best results are achieved with a combination of both observation types that provide complementary information on atmospheric clouds. This combination strongly improves the forecast of precipitation and other quantities throughout the whole range of 8-h lead time.

The Activity Concentrations, Radiation Contamination, and Hazards from Wastes and Soil Samples in Nasirabad Industrial Area, Chattogram, Bangladesh

Soils and other solid wastes from industrial areas of Nasirabad, Chattogram are usually dumped or used for land development. Information about the radioactivity level presented on these soil and wastes enables one to assess any possible radiological hazard to humankind by the use of such materials. A total of 37 (31 soils and 6 solid waste) samples near from different types of industries along four kilometre range were collected. The presence and activity concentrations of naturally occurred radioactive materials (NORM) and anthropogenic radionuclides in the samples were estimated using HPGe detector of 40% relative efficiency. The activity concentration of 226Ra, 232Th and 40K were found to be ranging from 8 ± 2 to 131 ± 18.33 with an average of 21 Bq·kg-1, 10 ± 2.69 to 133 ± 15.96 with an average of 40 Bq·kg-1 and 81 ± 22.68 to 930 ± 260.40 with an average of 449 Bq·kg-1 respectively. Besides this, some hazard indices like, the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and the activity concentration index (Iy) were calculated to assess the radiation hazard in this region. The averages of calculated hazard indices were within the normal limits, except the activity concentration index, which shows elevated values. The outcomes of this study could serve as important baseline radiological data for future epidemiological studies and environmental monitoring initiatives in the study area.

Atmospheric Monitoring of Methane in Beijing Using a Mobile Observatory

Cities have multiple fugitive emission sources of methane (CH4) and policies adopted by China on replacing coal with natural gas in recent years can cause fine spatial heterogeneities at the range of kilometers within a city and also contribute to the CH4 inventory. In this study, a mobile observatory was used to monitor the real-time CH4 concentrations at fine spatial and temporal resolutions in Beijing, the most important pilot city of energy transition. Results showed that: several point sources, such as a liquefied natural gas (LNG) power plant which has not been included in the Chinese national greenhouse gas inventory yet, can be identified; the ratio “fingerprints” (CH4:CO2) for an LNG carrier, LNG filling station, and LNG power plant show a shape of “L”; for city observations, the distribution of CH4 concentration, in the range of 1940–2370 ppbv, had small variations while that in the rural area had a much higher concentration gradient; significant correlations between CO2 and CH4 concentrations were found in the rural area but in the urban area there were no such significant correlations; a shape of “L” of CH4:CO2 ratios is obtained in the urban area in wintertime and it is assigned to fugitive emissions from LNG sources. This mobile measurement methodology is capable of monitoring point and non-point CH4 sources in Beijing and the observation results could improve the CH4 inventory and inform relevant policy-making on emission reduction in China.

Cryptic lineage differentiation among Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the northwest Indian Ocean

Phylogeography can provide insight into the potential for speciation and identify geographic regions and evolutionary processes associated with species richness and evolutionary endemism. In the marine environment, highly mobile species sometimes show structured patterns of diversity, but the processes isolating populations and promoting differentiation are often unclear. The Delphinidae (oceanic dolphins) are a striking case in point and, in particular, bottlenose dolphins (Tursiops spp.). Understanding the radiation of species in this genus is likely to provide broader inference about the processes that determine patterns of biogeography and speciation, because both fine-scale structure over a range of kilometers and relative panmixia over an oceanic range are known for Tursiops populations. In our study, novel Tursiops spp. sequences from the northwest Indian Ocean (including mitogenomes and two nuDNA loci) are included in a worldwide Tursiops spp. phylogeographic analysis. We discover a new ‘aduncus’ type lineage in the Arabian Sea (off India, Pakistan and Oman) that diverged from the Australasian lineage ∼261 Ka. Effective management of coastal dolphins in the region will need to consider this new lineage as an evolutionarily significant unit. We propose that the establishment of this lineage could have been in response to climate change during the Pleistocene and show data supporting hypotheses for multiple divergence events, including vicariance across the Indo-Pacific barrier and in the northwest Indian Ocean. These data provide valuable transferable inference on the potential mechanisms for population and species differentiation across this geographic range.

A sensitivity study of diffusional mass transfer of gases in tropical storm hydrometeors

This paper quantifies mass transfer and diffusional uptake rates of gases in liquid and solid hydrometeors within a cyclonic system. The non-availability of transfer rates for trace gases diffusing into storm hydrometeors, particularly over polluted urban conurbations, often constrain modellers the world over; however, this is an essential requirement to quantify the scavenging rates over the region concerned. The present paper seeks to provide modellers with such rates. Further, all of the earlier studies apply only to temperate regimes, and surprisingly identical formulations are assumed even for tropical conditions. The present analysis fills this research gap and couples cloud morphology with the associated thermodynamics through Weather Research and Forecasting (WRF) runs for cyclone Chapala (27 October 2015–04 November 2015) which battered the coasts of Yemen (Skamarock et al. 2008). It was a good example for undertaking this sensitivity study because the vertical extent spanned from around 0.75 to 16 km—enabling uptake rate calculations over both droplet and ice phases. Many of the diffusing gases were polar; the dipole moment of sulphur dioxide (SO2) and water vapour (H2O) was also included using a full Lennard–Jones model to compute the binary diffusivities of these gases as they diffused into the droplets mixed with water vapour. The first-order uptake rate constants ranged from 2.08 × 10−07 to 3.44 × 10−06 (s−1) and 1.97 × 10−07 to 7.81 × 10−07 (s−1) for H2O and SO2 respectively. The rates are of the order of 10−09 (s−1) for diffusion of water vapour into ice crystals further aloft. Closely linked with the gas uptake rates is another crucial parameter—the mass accommodation coefficient, α. The most widely used values are 1 and 0.036 (Pruppacher and Klett 1998)—the chosen values are restrictive and warrants a closer look. In storm systems, the vertical extents are in the kilometre range. Chapala with a large vertical extent warrants a full profile calculation. This study shows that for H2O vapour, α values range from a low of 0.004 reaching up to 0.046, and for SO2 impacting the liquid droplets, they are 0.004 to 0.077. Using these values in cloud droplet growth equations showed large changes in the positioning of the cloud base height up to about a maximum of 30%—a classic example illustrating the coupling of microphysics with dynamics suggesting that even large-scale models should cautiously use standard un-corrected accommodation and diffusion coefficients. Over polluted environments, aerosol number concentrations are very high—several hundreds of particles in a cubic centimetre—the cumulative effect involving such large-scale scavenging ends up in causing substantive changes in the actual scavenging rates. This is likely to affect overall radiative transfer calculations and must be corrected.

High resolution kilometric range optical telemetry in air by radio frequency phase measurement

We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

Accumulation and variability of maize pollen deposition on leaves of European Lepidoptera host plants and relation to release rates and deposition determined by standardised technical sampling.

BackgroundRisk assessment for GMOs such as Bt maize requires detailed data concerning pollen deposition onto non-target host-plant leaves. A field study of pollen on lepidopteran host-plant leaves was therefore undertaken in 2009–2012 in Germany. During the maize flowering period, we used in situ microscopy at a spatial resolution adequate to monitor the feeding behaviour of butterfly larvae. The plant-specific pollen deposition data were supplemented with standardised measurements of pollen release rates and deposition obtained by volumetric pollen monitors and passive samplers.ResultsIn 2010, we made 5377 measurements of maize pollen deposited onto leaves of maize, nettle, goosefoot, sorrel and blackberry. Overall mean leaf deposition during the flowering period ranged from 54 to 478 n/cm2 (grains/cm2) depending on plant species and site, while daily mean leaf deposition values were as high as 2710 n/cm2. Maximum single leaf-deposition values reached up to 103,000 n/cm2, with a 95 % confidence-limit upper boundary of 11,716 n/cm2.ConclusionsDaily means and variation of single values uncovered by our detailed measurements are considerably higher than previously assumed. The recorded levels are more than a single degree of magnitude larger than actual EU expert risk assessment assumptions. Because variation and total aggregation of deposited pollen on leaves have been previously underestimated, lepidopteran larvae have actually been subjected to higher and more variable exposure. Higher risks to these organisms must consequently be assumed. Our results imply that risk assessments related to the effects of Bt maize exposure under both realistic cultivation conditions and worst-case scenarios must be revised. Under common cultivation conditions, isolation buffer distances in the kilometre range are recommended rather than the 20–30 m distance defined by the EFSA.Electronic supplementary materialThe online version of this article (doi:10.1186/s12302-016-0082-9) contains supplementary material, which is available to authorized users.

Neutrino detection, position calibration and marine science with acoustic arrays in the deep sea

Arrays of acoustic receivers are an integral part of present and potential future Cherenkov neutrino telescopes in the deep sea. They measure the positions of individual detector elements which vary with time as an effect of undersea currents. At the same time, the acoustic receivers can be employed for marine science purposes, in particular for monitoring the ambient noise environment and the signals emitted by the fauna of the sea. And last but not least, they can be used for studies towards acoustic detection of ultra-high-energy neutrinos. Measuring acoustic pressure pulses in huge underwater acoustic arrays with an instrumented volume of the order of 100km3 is a promising approach for the detection of cosmic neutrinos with energies exceeding 1EeV. Pressure signals are produced by the particle cascades that evolve when neutrinos interact with nuclei in water, and can be detected over large distances in the kilometre range. In this article, the status of acoustic detection will be reviewed and plans for the future – most notably in the context of KM3NeT – will be discussed. The connection between neutrino detection, position calibration and marine science will be illustrated.

Daily Visibility and Mortality: Assessment of Health Benefits From Improving Visibility in Hong Kong

PP-31-017 Background/Aims: Visibility in Hong Kong has deteriorated significantly over 40 years with the frequency of visibility below 8 km in the absence of fog, mist, or precipitation, increasing from 6.6 days in 1968 to 54.1 days in 2007. Methods: During 1996–2006, we obtained mortality data for all natural and cardiorespiratory causes, visibility recorded as visual range in kilometers, temperature and relative humidity from an urban observatory, and concentrations of 4 criteria pollutants. A generalized additive Poisson regression model with penalized cubic regression splines was fitted to control for time–varying covariates. Results: For all natural causes of mortality an interquartile range of 6.5 km increase in visibility at lag 0–1 days was associated with an excess risk (ER%) (95% Confidence Interval) of −1.13 [−1.76, −0.49] for all ages and −1.37 [−2.09, −0.65] for ages 65+; for cardiovascular mortality of −1.31 [−2.49, −0.13] for all ages, and −1.72 [−3.00, −0.44] for ages 65+; for respiratory mortality of −1.92 [−3.35, −0.49] for all ages and −1.76 [−3.25, −0.28] for ages 65+. The estimated ER% for daily mortality derived from both visibility and air pollutant data were comparable in terms of magnitude, lag pattern, and dose-response relationships especially when using particulate matter with aerodynamic diameter ≤10 μm to predict mortality associated with visibility. Conclusion: Visibility provides a useful proxy for the assessment of environmental health risks from ambient air pollutants and a valid approach for the assessment of the public health impacts of air pollution and the benefits of air quality improvement measures in developing countries where pollutant monitoring data are scarce.

Daily visibility and mortality: Assessment of health benefits from improved visibility in Hong Kong

Visibility in Hong Kong has deteriorated significantly over 40 years with visibility below 8 km in the absence of fog, mist, or precipitation, increasing from 6.6 days in 1968 to 54.1 days in 2007. We assessed the short-term mortality effects of daily loss of visibility. During 1996–2006, we obtained mortality data for non-accidental and cardiorespiratory causes, visibility recorded as visual range in kilometers, temperature, and relative humidity from an urban observatory, and concentrations of four criteria pollutants. A generalized additive Poisson regression model with penalized cubic regression splines was fitted to control for time variant covariates. For non-accidental mortality, an interquartile range (IQR) of 6.5 km decrease in visibility at lag 0–1 days was associated with an excess risk (ER%) [95% CI] of 1.13 [0.49, 1.76] for all ages and 1.37 [0.65, 2.09] for ages 65 years and over; for cardiovascular mortality of 1.31 [0.13, 2.49] for all ages, and 1.72 [0.44, 3.00] for ages 65 years and over; and for respiratory mortality of 1.92 [0.49, 3.35] for all ages and 1.76 [0.28, 3.25] for ages 65 years and over. The estimated ER% for daily mortality derived from both visibility and air pollutant data were comparable in terms of magnitude, lag pattern, and exposure–response relationships especially when using particulate matter with aerodynamic diameter ≤10 μm to predict the mortality associated with visibility. Visibility provides a useful proxy for the assessment of environmental health risks from ambient air pollutants and a valid approach for the assessment of the public health impacts of air pollution and the benefits of air quality improvement measures in developing countries where pollutant monitoring data are scarce.

Staying Safe and Guilty Pleasures

Staying Safe and Guilty Pleasures

Monte Carlo simulation of curvature gauges by ray tracing

We have proposed recently a fibre optic device sensitive to minute curvatures with radii in the kilometre range. This ‘curvature gauge’ is intended primarily for the monitoring of deflection of structures under mechanical loading in applications in which strain gauges have traditionally been used. The sensitive zone of the curvature gauge is precision machined into the plastic optical fibre on grinding or milling machines. The cut-out produced removes a part of the fibre core and introduces a loss of light propagating along. The extent of such loss is related to the bend-radius of the fibre. Such a relationship, embodying the essence of the sensor's modulation principle, is examined in this paper by ray-tracing based on Monte Carlo simulation. A calibration curve is shown that relates the relative light-loss to the fibre curvature for different parameters of the sensitive zone (its depth, length and pitch of cuts). Through its asymptotic decay character, this nonlinear sensor characteristic reveals for the first time the existence of the device's sensitivity barrier that has limited its past applications to the measurement of curvatures with radii below about 2 to 3 km. We have also included an overview of the curvature gauge and have compared its performance with strain measuring instruments as the established benchmark.

Dynamical response of modulated Nd-doped kilometric fibre lasers

The response to pump-power modulation of Nd-doped fibre lasers with lengths in the kilometre range is reported. The timescales involved are close to those of subcritical regimes so that the transient relaxation oscillations are strongly damped. Furthermore, no competing effects (antiphase dynamics) occur between the two polarization eigenstates of the laser. Simple rate equations are shown to predict these behaviours. The experimental side of this study furnishes a definite demonstration of the importance of timescales in the dynamical properties of nonlinear and nonautonomous physical systems.

Drift speeds of equatorial electrojet irregularities of kilometre and metre sizes

Drift speeds of electron density irregularities in the equatorial electrojet region of sizes in the kilometre range (from VHF scintillations) and a few metres range (from VHF backscatter radar) have been compared under type I and type II irregularity conditions. The drift speeds, over the irregularity size range studied, match only when type II conditions prevail. The implications of the results are discussed in the light of the electrojet irregularity characteristics.

The localized origin of equatorial F region irregularity patches

An intensive study of nighttime irregularities of electron density in the equatorial ionosphere was performed in October 1976 by making 50‐MHz radar backscatter measurements at Jicamarca, Peru, and scintillation measurements of 249‐MHz transmissions from Les 9 at two ground stations (Ancon and Huancayo, both in Peru) as well as by aircraft flying in the vicinity of the stations. The 137‐MHz scintillations from the orbiting Wideband satellite were also recorded at Huancayo. The results of such measurements made on October 16–17, 1976, are discussed in this report. We find that on this particular night a large‐scale irregularity patch evolved first in the west, as was detected by the radar at Jicamarca, and drifted eastward to cause successive onsets of scintillation activity on propagation paths from Ancon and Huancayo. The observations indicate the east‐west dimension of the large‐scale structure to be 400 km drifting eastward at a speed of approximately 100 m/s, having a lifetime of several hours, and containing a hierarchy of irregularity scale sizes in the range of kilometers to meters causing both scintillations at 249 MHz and radar backscatter at 50 MHz.