Modelling the Impact of Magnetic Storms on Planetary Environments

2021 ◽  
Author(s):  
Souvik Roy ◽  
Dibyendu Nandy
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Flux Rope ◽  
Magnetic Storms ◽  
Helicity Injection ◽  
Magnetic Flux Ropes ◽  
Planetary Environments ◽  
The Impact ◽  
Host Stars ◽  
Atmospheric Mass

<p>Coronal mass ejections (CMEs), large scale transient eruptions observed in the Sun, are thought to also be spawned by other magnetically active stars. The magnetic flux ropes intrinsic to these storms, and associated high-speed plasma ejecta perturb planetary environments creating hazardous conditions. To understand the physics of CME impact and consequent perturbations in planetary environments, we use 3D compressible magnetohydrodynamic simulation of a star-planet module (CESSI-SPIM) developed at CESSI, IISER Kolkata based on the PLUTO code architecture.  We explore magnetohydrodynamic processes such as the formation of a bow-shock, magnetopause, magnetotail, planet-bound current sheets and atmospheric mass loss as a consequence of magnetic-storm-planetary interactions. Specifically, we utilize a realistic, twisted flux rope model for our CME, which leads to interesting dynamics related to helicity injection into the magnetosphere. Such studies will help us understand how energetic magnetic storms from host stars impact magnetospheres and atmospheres with implications for planetary and exoplanetary habitability.</p>

CAN INFRASTRUCTURE DEVELOPMENT ALLEVIATE MULTIDIMENSIONAL POVERTY? — EVIDENCE FROM CHINA

2021 ◽  
pp. 1-34
Author(s):  
YONGBO GE ◽  
YUEXIAO ZHU ◽  
WENQIANG ZHANG ◽  
XIAORAN KONG
Keyword(s):  
Poverty Alleviation ◽  
Capital Accumulation ◽  
High Speed ◽  
Large Scale ◽  
Multidimensional Poverty ◽  
Infrastructure Development ◽  
Public Infrastructure ◽  
Regional Heterogeneity ◽  
The Impact ◽  
Insight Into

We investigate the impact of the construction of large-scale high-speed railways (HSRs) on regional multidimensional poverty in China. We find that the opening of HSRs can reduce this poverty indicator. This association is robust to a series of checks. Regarding the mechanisms, the opening of HSRs can improve regional accessibility, enhance local tourism, increase labor mobility and promote human capital accumulation, which alleviates multidimensional poverty. Further research indicates the regional heterogeneity of the effect. This research supplements poverty alleviation theory from the perspective of public infrastructure and offers insight into how multidimensional poverty arises and how it can be alleviated.

Optimizing Electrical Protection for Medium Voltage Controller Lineup to Improve Liquids Pipelines Operation Reliability and Safety

2018 ◽  
Author(s):  
Ting Yu ◽  
Tushar Chaitanya
Keyword(s):  
Proximity Effect ◽  
Incident Energy ◽  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Partial Discharge ◽  
Light Detection ◽  
Medium Voltage ◽  
Voltage Controller ◽  
The Impact

MV (Medium Voltage) controller lineup electrical protection is crucial in protecting the equipment from large scale damage upon the occurrence of an electrical fault, reducing the time to restore power, thereby minimizing the impact to liquids pipelines operation. The paper discusses typical electrical failure modes that may occur in MV controller lineups, and demonstrates practical relaying engineering techniques that enable fast and effective fault clearing. Electrical faults in the MV controller lineup are often arcing type, commonly involve ground. Mitigating arc hazards in MV Class E2 controller lineups has traditionally been challenging without sacrificing the protection selectivity. As the paper demonstrates, a relaying scheme with the combined use of high-speed light-sensing and overcurrent detection will effectively mitigate the incident energy, while maintaining the protection selectivity for non-arcing overcurrent events. For new MV controller lineups, in addition to the “high-speed light detection and fault interruption”, zone-selective interlocking (ZSI) can also be a practical solution in improving relay protection speed, thus reduce the chance of severe arc flash occurrences. ZSI is particularly effective for fault occurrences on the line side of the phase CTs, busways or main incoming circuits. The ZSI scheme can be implemented on both Class E2 and circuit breaker (VCB) type MV controller lineups, however, with slightly different trip logic due to the limited fault clearing capability of the contactor. Although there are multiple contributing factors, the direct causes of electrical failures in MV controller lineup are commonly related to improper power cable installation and handling, potentially leading to premature insulation breakdown due mainly to the proximity effect and/or partial discharge. Inadequate cable separation and prolonged fault trip delay can increase the possibility of arcing fault occurrence. This can usually be mitigated through appropriate cable spacing, adequate conductor insulation, and optimized fault detection schemes. The paper provides overviews of the mechanisms of proximity effect and partial discharge propagation, and the modern relaying approaches for accurate fault type discrimination and facilitating fast fault interruption. Two case studies are provided in the paper as an aid in understanding the electrical fault mechanism originated from cable insulation failure, demonstrating the incident energy reduction before and after the implementation of high-speed light detection and fault interruption solutions on an existing MV controller lineup.

scholarly journals Stochastic Risk Assessment with a Lagrangian Solution for the Optimal Cost Allocation in High-Speed Rail Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jing Zuo ◽  
Jianwu Dang ◽  
Min Lyu
Keyword(s):  
Risk Assessment ◽  
High Speed ◽  
Large Scale ◽  
Cost Allocation ◽  
Optimal Allocation ◽  
High Speed Rail ◽  
Maintenance Costs ◽  
Optimal Cost ◽  
The Impact ◽  
Stochastic Risk

In large-scale high-speed rail networks (HSRNs), the occurrence of occasional malfunctions or accidents is unavoidable. The key issue considered in this study is the optimal allocation of the maintenance costs, based on the stochastic risk assessment for HSRNs. Inspired by the theoretical risk evaluation methods in the complex network, three major factors, including the local effects, global effects, and component self-effects are considered in the process of assessing the impact on the network components (nodes or lines). By introducing the component failure occurrence probability, which is considered to be an exponential function changing with the component maintenance costs, a feasible stochastic risk assessment model of the HSRNs together with the component impact assessment is proposed that can better unify the impact assessment of both the high-speed rail stations and railways. An optimal allocation algorithm based on a Lagrangian relaxation approach is designed. Correspondingly, the optimal cost allocation scheme can be determined using the algorithm to eliminate the various HSRN risks under the given costs. Furthermore, a real-world case study of the HSRNs in eastern China is illustrated. Compared with the genetic algorithm, the simulation shows that the approach can solve the optimal cost allocation problem to more effectively reduce the risks of large-scale HSRNs in practice.

Deformation, heating and melting of solids in high-speed friction

1961 ◽  
Vol 260 (1303) ◽  
pp. 433-458 ◽  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Frictional Heating ◽  
Vertical Axis ◽  
High Viscosity ◽  
Molten Material ◽  
General Behaviour ◽  
Low Viscosity ◽  
Heavy Loads ◽  
The Impact

An experimental study has been made of the effects of frictional heating on the deformation of solids rubbing at very high speeds and at reasonably heavy loads. A new method for measuring the friction under these conditions is described. A steel ball, rapidly spinning round its vertical axis, is allowed to fall a short distance and to bounce off an inclined flat solid surface. The friction of steel on various solids in a vacuum of ca . 10 -4 mm Hg, at sliding speeds up to 700 m/s, is determined from the measured direction of the ball’s horizontal velocity after the impact. In addition, separate piezo-electric measurements are made of the load and the friction force. Again the coefficient of friction is found to decrease with increasing sliding speed. The general behaviour is similar to that observed at light loads but there are important differences. With heavy loads the deformation of the solids appears to be primarily plastic. Within a very short time after being brought into contact with a fast-moving surface, solids with a sufficiently low melting point melt on a large scale so that a continuous film of molten material is developed over the area of contact. The resistance to motion is determined primarily by this liquid film so that it may now increase as the speed rises. The heating due to the shearing of this film causes the solid to melt away rapidly, and as a result the wear rate of such solids usually becomes great at high sliding speeds. Certain polymers, however, exhibit a greater wear resistance than metals and other solids which possess a low viscosity in the molten state. Calculations indicate that in these polymers, owing to their high viscosity, the temperature of the sheared film may be considerably higher than the melting temperature. As a consequence, a larger proportion of the heat developed by the shearing may be absorbed in the already molten material, and less heat will be available for further melting. Gas liberated by thermal decomposition may also reduce the friction and wear.

The deformation of solids by liquid impact at supersonic speeds

1961 ◽  
Vol 263 (1315) ◽  
pp. 433-450 ◽  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Impact Load ◽  
Turbine Blades ◽  
Stress Waves ◽  
Liquid Jet ◽  
High Speeds ◽  
Liquid Impact ◽  
The Impact ◽  
Very High

A study has been made of the deformation of solids at high rates of strain which are produced by the impact of a small cylinder or jet of liquid on the surface of the solid. A method is developed for projecting this jet against the solid at velocities up to 1200 m/s. The subsequent deformation of the solid under impact and the behaviour of the liquid is observed by high-speed photographic methods. The magnitude and duration of the impact load are also measured by using a piezo-electric transducer. The mode of deformation of the solid has been investigated for plastic, elastic and brittle materials. There is evidence that the liquid jet, on impact, behaves initially in a compressible manner. Part of the deformation is due to these compressible effects and part to the shearing action of the liquid flowing at very high speeds across the surface. If the head of the jet has an appropriate shape (e.g. wedge shaped) the velocity of flow across the surface may be much greater than the velocity of approach. It is found that there are five general types of deformation produced in the solid. There are (i) circumferential surface fractures, (ii) subsurface flow and fractures, (iii) large-scale plastic deformation, (iv) shear deformation around the periphery of the impact zone, and (v) fracture due to the reflexion and interference of stress waves. The predominating mode of deformation depends primarily on the mechanical properties of the solid and on the velocity of impact. The observations have a bearing on the practical problem of the erosion of aircraft flying at high speed through rain and on the erosion of turbine blades.

Backlit Imaging of a Circular Plunging Jet With Floor Interactions

2020 ◽  
Author(s):  
Roy A. Pillers ◽  
Theodore J. Heindel
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Air Entrainment ◽  
Ocean Waves ◽  
Jet Flows ◽  
Small Scale ◽  
Bubble Plume ◽  
Plunging Jets ◽  
Compression Effects ◽  
The Impact

Abstract Plunging jets occur when a liquid stream enters a slower moving or stationary liquid body after first passing through a gaseous region. The most commonly studied plunging jet structure is that of water entering water. Plunging jets have been studied in order to understand and model mixing and transport from the atmosphere into the liquid. Shear forces at the edge of the jet cause air entrainment both in the free jet and at the impact point on the pool surface. Plunging jet applications range from large scale environments, such as ocean waves, waterfalls, wastewater treatment, and dams, to small scale environments, such as liquid-gas fuel mixing, mineral separation, and molten metal pouring. The majority of the literature today involve facilities designed to approximate an infinite liquid pool; few of these studies take into account the compression effects prevalent in several of the real systems. Therefore, a tank has been developed for the visualization of plunging jet flows with varying pool depth. This study involved the creation of a 32 cm by 32 cm, 91.4 cm deep rectangular acrylic tank with an interior adjustable acrylic bottom for the visualization of plunging jet flows with bottom compression effects. The pool height was held constant using a secondary tank with an overflow weir. In this study high-speed backlit images were taken of the plunging jet region. Preliminary results indicate that there is a significant change in both the shape and estimated entrained air volume when the plunging jet is subjected to compression effects. This is attributed to the plate spreading the bubble plume and allowing for easier bubble rise.

scholarly journals Stellar CME activity and its possible influence on exoplanets' environments: Importance of magnetospheric protection

2013 ◽  
Vol 8 (S300) ◽  
pp. 335-346 ◽  
Author(s):  
Maxim L. Khodachenko ◽  
Yury Sasunov ◽  
Oleksiy V. Arkhypov ◽  
Igor I. Alexeev ◽  
Elena S. Belenkaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stellar Wind ◽  
High Speed ◽  
Large Scale ◽  
Magnetized Plasma ◽  
Impact Factors ◽  
Interplanetary Shocks ◽  
Planetary Environments ◽  
Close Orbit ◽  
The Magnetic Field

AbstractCMEs are large-scale magnetized plasma structures carrying billions of tons of material that erupt from a star and propagate in the stellar heliosphere, interacting in multiple ways with the stellar wind. Due to the high speed, intrinsic magnetic field and the increased plasma density compared to the stellar wind background, CMEs can produce strong effects on planetary environments when they collide with a planet. The main planetary impact factors of CMEs, are associated interplanetary shocks, energetic particles accelerated in the shock regions, and the magnetic field disturbances. All these factors should be taken into account during the study of evolutionary processes on exoplanets and their atmospheric and plasma environments. CME activity of a star may vary depending on stellar age, stellar spectral type and the orbital distance of a planet. Because of relatively short range of propagation of majority of CMEs, they impact most strongly the magnetospheres and atmospheres of close orbit (< 0.1 AU) exoplanets.

LARGE-SCALE AIR POLLUTION MODELING IN EUROPE UNDER DIFFERENT CLIMATIC SCENARIOS

2019 ◽  
Vol 01 (02) ◽  
pp. 1950009 ◽  
Author(s):  
ZAHARI ZLATEV ◽  
IVAN DIMOV ◽  
ISTVÁN FARAGÓ ◽  
KRASSIMIR GEORGIEV ◽  
ÁGNES HAVASI
Keyword(s):  
Air Pollution ◽  
High Speed ◽  
Large Scale ◽  
Chemical Species ◽  
Modern Society ◽  
Climatic Changes ◽  
Human Beings ◽  
Pollution Levels ◽  
Pollution Modeling ◽  
The Impact

The treatment of large-scale air pollution models is not only important for modern society, but also an extremely difficult task. Five important physical and chemical processes: (1) horizontal advection, (2) horizontal diffusion, (3) vertical exchange, (4) emission of different pollutants and (5) dry and wet deposition have to be united and handled together. This leads to huge computational problems which have to be treated on modern high-speed parallel architectures by using advanced numerical methods. The computational difficulties are vastly increased when such models are used in the investigation of the impact of climatic changes on high pollution levels that are often exceeding certain critical concentrations and, therefore, are becoming harmful for plants, animals and human beings. There are two major reasons for the great increase in computational difficulties: (a) it is necessary to run the discretized data on fine spatial grid models over very long time-periods consisting of many consecutive years and (b) different scenarios are to be used in order to investigate the sensitivity of the pollution levels to systematic variations of several carefully selected key parameters. How the major difficulties can be resolved is explained here. Furthermore, many results are presented in order to demonstrate the ability of the model to handle successfully the huge computational tasks by using fine space and time discretization and by applying a chemical scheme with many chemical species participating in several hundred chemical reactions. Our results indicate that the climatic changes will often lead to some increases in the pollution levels.

A Novel Low Power Technique for FinFET Domino OR Logic

2020 ◽  
pp. 2150117
Author(s):  
Kajal ◽  
Vijay Kumar Sharma
Keyword(s):  
Power Dissipation ◽  
High Speed ◽  
Large Scale ◽  
Logic Gates ◽  
Leakage Power ◽  
Oxide Semiconductor ◽  
Domino Logic ◽  
Large Power ◽  
Leakage Reduction ◽  
The Impact

Excessive scaling of complementary metal oxide semiconductor (CMOS) technology is the main reason of large power dissipation in electronic circuits. Very large-scale integration (VLSI) industry has chosen an alternative option known as fin-shaped field effect transistor (FinFET) technology to mitigate the large power dissipation. FinFET is a multi-gate transistor which dissipates less leakage power as compared to CMOS transistors, but it does not completely resolve the problem of power dissipation. So, leakage reduction approaches are always required to mitigate the impact of power dissipation. In this paper, cascaded leakage control transistors (CLCT) leakage reduction technique is proposed using FinFET transistors. CLCT approach is tested for basic static logic circuits like inverter, 2-input NAND and NOR gates and compared with the existing leakage reduction techniques for leakage power dissipation and delay calculations at 16 and 14 nm technology nodes using Cadence tools. CLCT approach shows the effective reduction of leakage power with minimum delay penalty. As the domino logic gates are widely used in large memories and high-speed processors therefore, CLCT approach is further utilized for footless domino logic (FLDL) and compared with the available methods at 14[Formula: see text]nm technology node. CLCT approach reduces 35.16% power dissipation as compared to the conventional domino OR logic. Temperature and multiple parallel fin variations are estimated for the domino OR logic to check its reliable operation. CLCT approach has high-noise tolerance capability in term of unity noise gain (UNG) for domino OR logic as compared to the other methods.

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