Lightning

Traditionally, the location of lightning strike points has been determined by using the rolling sphere method, but recently the collection volume method (CVM) has also been proposed for the placement of air terminals on complex structures. Both these methods are empirical in nature and a more advanced model based on physics of discharges is needed to improve the state of affairs. This model is used to evaluate the striking distance from corners and air terminals on actual buildings and the results are qualitatively compared with the predictions of the rolling sphere method and the CVM. The results show that the striking distance not only depends upon the prospective return stroke current and the geometry of the building, but also on the lateral position of the downward leader with respect to the strike point. A further analysis is performed to qualitatively compare the lightning attraction zones obtained with the CVM and the leader inception zones obtained for a building with and without air terminals. The obtained results suggest that the collection volume concept overestimates the protection areas of air terminals placed on complex structures, bringing serious doubts on the validity of this method.

The article reviews the current literature related to lightning and makes a case for using lightning as an alternative source of energy. Objections to using lightning as an alternative source of energy are listed. Current literature is reviewed and articles are suggested as useful for building a tower, or using rockets or lasers to target a strike, or for quantifying a lightning strike.

Designing a fuel-sampling program that accurately and efficiently assesses fuel load at relevant spatial scales requires knowledge of each sample method’s strengths and weaknesses. We obtained loading values for six fuel components using five fuel load sampling techniques at five locations in western Montana, USA. The techniques included fixed-area plots, planar intersect, photoloads, a photoload macroplot, and a photo series. For each of the six fuels, we compared (1) the relative differences in load values among techniques and (2) the differences in load between each method and a reference sample. Totals from each method were rated for how much they deviated from totals for the reference in each fuel category. The planar-intersect method, which used 2.50 km of transects, was rated best overall for assessing the six fuels. Bootstrapping showed that at least 1.50 km of transect were needed to obtain estimates that approximate the reference sample. A newly developed photoload method,...

Received: 3 August 2020 Accepted: 26 December 2020 The aim of this paper is to perform a parametric study in order to analyze factors having an effect on the vertical lightning field polarization to the CN-Tower in Canada, and estimate with numerical simulation, the horizontal distance for which the reversed polarity will occur. The calculation is performed using the Finite-Difference-TimeDomain technique in two dimensions (2D-FDTD), the spatial-temporal current propagation through the lightning channel and through the high structure is represented by the lumped-series voltage-source model. The obtained results show that the vertical electric lightning field behavior has a dual polarity, the transition from a negative waveform to a positive one is observed at different observation points localized near the elevated object influencing by each modification made to the tower-parameters, the medium conductivity and the return stroke speed value. These results can contribute to the under...

The horizontal electric field both at points above and below ground in the vicinity of lightning return strokes were evaluated by numerical solution of Sommerfeld's integrals. Results are presented for ground conductivities in the range of 0.01 and 0.0001 S/m. The results are compared with the following approximate procedures used in the literature to calculate horizontal electric fields: (a) the surface impedance approximation, (b) the quasi static approximation frequently used in lightning protection standards and (c) Cooray's simplified formula for the computation of underground electric field. Based on this comparison the distance range in which these approximations are valid is obtained. The results obtained show that: (1) The surface impedance approximation can generate correct horizontal electric field when the distance to the point of observation is larger than about 50 m, 100 m, and 500 m for ground conductivities of 0.01, 0.001 and 0.0001 S/m respectively.

Urban flooding is an inevitable problem for many cities around the world. In the present paper, modelling approaches and principles for analyses of urban flooding are outlined. The paper shows how urban flooding can be simulated by one-dimensional hydrodynamic ...

The parameter terms (second column) for log (Aerial shrub cover + 1) × scale and log (Aerial tree cover + 1) × scale were incorrectly given positive rather than negative values. The correct values are: log (Aerial shrub cover + 1) × scale = −0.005 (0.002) log (Aerial tree cover + 1) × scale = −0.002 (0.001)

Positive cloud-ground lightning is considerably more complex and less studied compared to the negative lightning. This paper aims to measure and characterize the significant parameters of positive return strokes electric field, namely, the zero-to-peak rise time, 10–90% rise time, slow front duration, fast transition rise time (10–90%), zero-crossing time, and opposite polarity overshoot relative to peak. To the best of the authors’ knowledge, this is the first time such detailed characteristics of positive lightning in Malaysia are thoroughly analyzed. A total of 41 positive lightning flashes containing 48 return strokes were analyzed. The average multiplicity is 1.2 strokes per flash. The majority of positive lightning was initiated from the primary positive charge rather than as a byproduct of in-cloud discharges. The cumulative probability distribution of rise time parameters, opposite polarity overshoot relative to peak, and slow front amplitude relative to peak are presented. ...

In the literature, three procedures have been used to calculate the electromagnetic fields from return strokes. In the first technique, the source is described only in terms of current density and the fields are expressed entirely in terms of the return-stroke current. In the second technique, the source is expressed in terms of the current and the charge densities and the fields are given in terms of both the current and the charge density. In the third technique, the fields are expressed in terms of the apparent charge density. The fields are connected to the source terms through the vector and scalar potentials. In this paper, the standard equations for the electromagnetic fields generated by an accelerating charge are utilized to evaluate the electromagnetic fields from lightning return strokes. It is shown that the total fields evaluated at any distance using these expressions are identical to those obtained using other techniques. However, the composition of the terms that vary as 1/R, 1/R 2 , and 1/R 3 of the total electric field is different from those of other formulations. In the case of the transmission-line model, where the return stroke is described as a current pulse propagating with uniform velocity, radiation emanates only from the bottom of the channel where current is generated. When the speed of propagation is equal to the speed of light, the total field throughout the entire space becomes radiation. The procedure is also applied here to obtain the electric fields of the traveling-current-source model. The electric fields obtained for this case, too, agree with the previous study. It is also shown how the equations can be applied rather conveniently to evaluate: 1) the electromagnetic fields generated by current pulses propagating along overhead power lines; and 2) the electromagnetic fields generated by vertical conductors and towers during lightning strikes.

1] A performance assessment of the Worldwide Lightning Location Network (WWLLN) is presented using the National Lightning Detection Network (NLDN) as ground truth, over unprecedented time and spatial scales. The study spans 3 years, from 5 April 2006 to 31 March 2009, throughout the contiguous United States. The capabilities of the network are shown to improve greatly from the first to the third year of the study, with an overall detection efficiency of cloud-to-ground flashes increasing from 3.88% in 2006 −2007 to 10.30% in 2008−2009. The WWLLN cloud-to-ground detection efficiency is found to be strongly dependent on peak current and polarity, attaining values larger than 10% (35%) for currents stronger than ±35 kA (−130 kA) and values less than 2% for currents between 0 and −10 kA. The location accuracy is found to have a northward and westward bias, with average location errors of 4.03 km in the north-south and 4.98 km in the east-west directions, respectively. The WWLLN is shown to have strong limitations in capturing the diurnal cycle, missing both the timing of the maximum and minimum lightning activity (around 1600 and 0900 LT, respectively), and the amplitude of the cycle as well. It is found that in 3 h intervals, the number of flashes in the WWLLN has some proportionality to the number of flashes in the NLDN, suggesting that the WWLLN has strong potential for meteorological applications.

In 1999, the first sprites were observed above European thunderstorms using sensitive cameras. Since then, Eurosprite campaigns have been conducted to observe sprites and other transient luminous events (TLEs), expanding into a network covering large parts of Europe and coastal areas. In 2009 through 2013, the number of optical observations of TLEs reached a peak of 2000 per year. Because of this unprecedented number of European observations, it was possible to construct 5 a climatology of 8394 TLEs observed above 1018 thunderstorm systems, and study for the first time their distribution and seasonal cycle above Europe and parts of the Mediterranean Sea. The number of TLEs per thunderstorm was found to follow a power law, with less than 10 TLEs for 801 thunderstorms and up to 195 TLEs above the most prolific one. The majority of TLEs were classified as sprites, 641 elves, 280 halos, 70 upward lightning, 2 blue jets and 1 gigantic jet. The climatology 10 shows intense TLE activity during summer over continental areas, and in late autumn over coastal 1 vised manuscript with changes highlighted Click here to access/download;attachment to manuscript;Arnone2019_SG_revised_manuscript_RM_changes_ lick here to view linked References areas and sea. The two seasons peak respectively in August and November, separated by March and April with almost no TLEs, and a relative minimum around September. The observed TLE activity, i.e. mostly sprites, is shown to be largely consistent with lightning activity, with a 1/1000 of observed TLE to lightning ratio in regions with most observations. The overall behavior is consistent among individual years, making the observed seasonal cycle a robust general feature of TLE activity above Europe. Article Highlights • Detailed climatological study of TLEs and lightning above Europe produced for the first time • Seasonal cycle of TLEs and lightning with two active seasons in summer over land and autumn over sea and coastal areas • Power law distribution of number of TLEs per thunderstorm Keywords Thunderstorms, lightning, transient luminous events, ground-based observations, Europe, climatology. 1 Introduction 1.1 Transient luminous events Three decades ago, a test low-light camera recorded a sprite (Franz et al., 1990), a spectacular discharge extending for tens of km above a thunderstorm. It was the first discovery of a whole family of upper atmosphere electrical processes, collectively known as transient luminous events (TLEs-see

Low energy buildings use less than 50 % of the energy used in typical buildings. Such energy efficient buildings can only be achieved by applying unconventional approaches. However, the applicability of the unconventional strategies and techniques is challenging. This proposal presents an innovative idea that can be applied to overcome barriers to implementation of one of these unconventional techniques that used to maximize the utilization of daylighting within buildings.
Daylight guidance systems (DGS) deliver daylight into windowless and remote parts of buildings via light ducts or fiber optics. DGS that based on light duct to channel daylight are relatively economical, more likely to maintain daylight characteristics, and capable of delivering both direct and diffused daylight. However, they still lack widespread use due to installation difficulty. They use light ducts that occupy significant spaces to distribute daylight. The integration of DGS light ducts and HVAC ducts emerges as a novel and promising solution. The integrated dual ducting system has the potential to maximize the utilization of daylighting, reduce costs and avoid conflicts between building systems.
The widely used HVAC systems uses duct networks already integrated with the other building systems. The HVAC ducts are capable of reaching most spaces, and are of comparable size to light ducts. Thus, they are a prime target for the development of dual ducts; a single duct to transport and distribute both air and light.
The proposed system is very practical and benefit from the available facilities to produce a new product and propose a new design approach. Cooperation between architect/lighting designer and HVAC designer can be made to convert conventional ducts network design and material into the dual ducting system. There is no other product on the market that is used to deliver both air and daylight, and no other system has been designed or developed to provide this service.

Here the readers can find basics of modern  lightning protection technologies and essentials of grounding technics including products and other devices manufactured by ORBITAL Lightning Protection.

More cites and information for https://orbitaltechs.com

Wildland fuelbeds are exceptionally complex, consisting of diverse particles of many sizes, types and shapes with abundances and properties that are highly variable in time and space. This complexity makes it difficult to accurately describe, classify, sample and map fuels for wildland fire research and management. As a result, many fire behaviour and effects software prediction systems use a generalised description of fuels to simplify data collection and entry into various computer programs. There are several major fuel description systems currently used in the United States, Canada and Australia, and this is a source of confusion for many in fire management. This paper (1) summarises the challenges of describing fuels, (2) contrasts approaches (association, classification and abstraction) for developing fuel description systems and (3) discusses possible future directions in wildland fuel description and science to transition to a universal fuel description system. Most discussio...

a b s t r a c t Different approaches are used in estimating the global production of NO x by lightning flashes, including field measurements carried out during thunderstorm conditions, theoretical studies combining the physics and chemistry of the electrical discharges, and measurements of NO x yield in laboratory sparks with subsequent extrapolation to lightning. In the latter procedure, laboratory data are extrapolated to lightning using the energy as the scaling quantity. Further, in these studies only the return strokes are considered assuming that contributions from other processes such as leaders, continuing currents, M components, and K processes are negligible. In this paper, we argue that the use of energy as the scaling quantity and omission of all lightning processes other than return strokes are not justified. First, a theory which can be used to evaluate the NO x production by electrical discharges, if the current flowing in the discharge is known, is presented. The results obtained from theory are compared with the available experimental data and a reasonable agreement is found. Numerical experiments suggest that the NO x production efficiency of electrical discharges depends not only on the energy dissipated in the discharge, but also on the shape of current waveform. Thus, the current signature, can influence extrapolation of laboratory data to lightning flashes. Second, an estimation of the NO x yield per lightning flash is made by treating the lightning flash as a composite event consisting of several discharge processes. We show that the NO x production takes place mainly in slow discharge processes such as leaders, M components, and continuing currents, with return strokes contributing only a small fraction of the total NO x . The results also show that cloud flashes are as efficient as ground flashes in NO x generation. In estimating the global NO x production by lightning flashes the most influencing parameter is the length of the lightning discharge channel inside the cloud. For the total length of channels inside the cloud of a typical ground flash of about 45 km, we estimate that the global annual production of NO x is about 4 Tg(N).

Electric radiation fields produced by lightning cloud flashes have been analyzed using Fourier methods to obtain amplitude spectra for frequencies in the range of 20 kHz to 20 MHz. Time to thunder measurements were used to extract the distances to the cloud flashes from the measurement site. The spectra were generated by analyzing the first 10 ms time window of cloud flashes with 10 ns sampling resolution, and they show f-1 frequency dependence up to 2 MHz followed by f-2 dependence and higher for frequencies above 2 MHz. The results agree very well with previous measurements carried out for individual pulses produced by various lightning processes. By utilizing digital filters, it has been shown that measurements taken with narrowband filters agree with the results produced under wideband measurements

: A sounding climatology of a variety of parameters commonly used to forecast deep, moist convection using upper-air observations is developed. The data set includes 0000 and 1200 UTC rawinsonde data (approximately 3629 soundings) from Laughlin AFB, TX from April September 1995 2004. Cloud-to-ground lightning data, surface observations, and severe weather reports from the Storm Prediction Center (SPC) SeverePlot2 Program were used to categorize soundings as representative of conditions for no convection, light convection, convection within vicinity, moderate severe convection, or severe convection. Indices, including convective available potential energy (CAPE) and mean layer CAPE (MLCAPE), along with sounding parameters and combinations of such as 0-2 and 0-6 km bulk shear, 700-500 mb lapse rate, lifted condensation level (LCL) and mean layer LCL (MLLCL) heights, are examined in an attempt to distinguish between moderate and severe convection. The results show that the 0-6 km bulk ...

Various methods are used to locate cloud-to-ground lightning flash. The accuracy of the methods depends on the number of sensor stations, station topology, mathematical model adopted for the analyses, and type of measuring equipment. For a single station with the configuration of short baseline in a measuring system, the accuracy analysis is mostly based on the chosen mathematical equations (and all relative assumptions) which can be solved in either linear or nonlinear mode. This paper concentrates on the simulation of a lightning flash based on Time of Arrival (TOA) method by utilizing three broadband antennas. The accuracy of the TOA method is also evaluated in this work. A Matlab based simulation of the measuring system is implemented to construct a randomly located lightning flash with its corresponding electromagnetic radiation. Then, suitable mathematical models used as measurement systems based on the TOA method to determine the azimuth and elevation angles.

Ferromagnetic materials, such as steel, are used for shielding of power and telecommunication cables. These shields often provide path for currents during faults or lightning and are important for the integrity and safety of electrical systems and devices. Since such currents might be with low-or high-frequency content, and of low or high intensity, ferromagnetic shield behavior might be quite different due to hysteresis. This paper describes a method for analyzing the dynamic behavior of ferromagnetic cable shields based on the Jiles model of hysteresis. The solution is implemented in ATP-EMTP, which allows one to analyze the complex behavior of ferromagnetic cable shields in conjunction with that of the other elements of the power system. Due to limitations of the model of hysteresis, application of the proposed model is limited to frequencies up to about 10 kHz. The model is illustrated for a practical 100-m-long cable.

Nepal has a very large topographical variation; this elevation change has a major influence on lightning occurrence and human casualties. The Himalayan peaks cover the northern part of Nepal with low population density, the middle is covered by hills with intermediate density, and the southern plain with the greatest density. This study will leverage lightning detection by Vaisala's Global Lightning Dataset GLD360 network with a recent detailed compilation of lightning casualties from 2011 through 2020. Over one million lightning strokes per year were detected from 2016 through 2020. Stroke density is least over high elevations to the north, moderate in hilly regions, and very frequent over the south. The thunderstorm season begins in March and ceases by August after the annual monsoon cycle. Of all the natural disasters, lightning has been recorded to be the second highest killer after earthquakes. The Ministry of Home Affairs reports an average of 103 lightning deaths per year. The fatality rate of 3.8 deaths million À1 year À1 is highest among the South Asian countries. Fatalities over high mountains are rare, with most casualties over the center of Nepal. Lightning Fatality Risk is not a good indicator of the fatalities that occur in a district.

A physics-based model describing the thermal interaction between a lightning channel and a composite structure has been developed. The model includes: (i) spatial and temporal evolution of the lightning channel as a function of the electric current waveform; (ii) temporary and spatially non-uniform heat flux generated at the composite structure, where the heat flux is an explicit function of the electric current waveform and the instant lightning channel radius; (iii) nonlinear transient heat transfer problem formulation for layered anisotropic composites that accounts for temperature-dependent material properties,  a moving boundary of the expanding lightning channel, and phase transition moving boundary associated with instantaneous material removal due to sublimation. The model is applied for evaluation of thermal damage of the tip glass fiber reinforced polymer matrix composite panel of the Sandia 100-meter All-glass Baseline Wind Turbine Blade (SNL 100-00) subjected to lightning strike.

Various methods are used to locate cloud-toground lightning flash. The accuracy of the methods depends on the number of sensor stations, station topology, mathematical model adopted for the analyses, and the type of measuring equipment. For a single station with the configuration of short baseline in a measuring system, the accuracy of analysis is mostly based on the chosen mathematical equations (and assumptions) which can be solved in either linear or nonlinear mode. This paper concentrates on the simulation of a lightning flash and its detection based on the Time of Arrival (TOA) method by utilizing four broadband antennas. The accuracy of the TOA method is also evaluated in this work. A Matlab based simulation of the measuring system is implemented to construct a randomly located lightning flash with its corresponding electromagnetic radiation. Then, suitable mathematical models used as measurement systems based on the 3-antenna TOA method to determine the azimuth and elevation angles, which in turn can be used for the calculation of flash coordinates in term of (X,Y,Z) with the help of the fourth antenna.

This paper discusses the modes of actuation and misoperation of the automatic disconnector of distribution surge arresters. Taking into account the laboratory test results and field data search campaigns, the main problems concerning the operation of these devices and how it affects the reliability of the surge protection of transformers are discussed. In general, the misoperation of the disconnector is a design problem, concerning materials and production quality control. Considering this, a new design is also proposed, trying to avoid the main operation problems, resulting in a more simple and reliable device.

Human CO2 emissions may drive the Earth into a next greenhouse state. They can be mitigated by accelerating weathering of natural rock under the uptake of CO2. We disprove the paradigm that olivine weathering in nature would be a slow process, and show that it is not needed to mill olivine to very fine, 10 μm-size grains in order to arrive at a complete dissolution within 1-2 y. In high-energy shallow marine environments olivine grains and reaction products on the grain surfaces, that otherwise would greatly retard the reaction, are abraded so that the chemical reaction is much accelerated. When kept in motion even large olivine grains rubbing and bumping against each other quickly produce fine clay- and silt-sized olivine particles that show a fast chemical reaction. Spreading of olivine in the world’s 2% most energetic shelf seas can compensate a year’s global CO2 emissions and counteract ocean acidification against a price well below that of carbon credits.

Wildfires that spread into wildland-urban interface (WUI) communities present significant challenges on several fronts. In the United States, the WUI accounts for a significant portion of wildland fire suppression and wildland fuel treatment costs. Methods to reduce structure losses are focussed on fuel treatments in either wildland fuels or residential fuels. There is a need for a well-characterised, systematic testing of these approaches across a range of community and structure types and fire conditions. Laboratory experiments, field measurements and fire behaviour models can be used to better determine the exposure conditions faced by communities and structures. The outcome of such an effort would be proven fuel treatment techniques for wildland and residential fuels, risk assessment strategies, economic cost analysis models, and test methods with representative exposure conditions for fire-resistant building designs and materials.

Global warming mitigation calculations require consistent procedures for handling time in order to compare 'permanent' gains from energy-sector mitigation options with 'impermanent' gains from many forest-sector options. A critical part of carbon accounting methodologies such as those based on 'ton-years' (the product of the number of tons of carbon times the number of years that each ton is held out of the atmosphere) is definition of a time horizon, or the time period over which carbon impacts and benefits are considered. Here a case is made for using a time horizon of 100 years. This choice avoids distortions created by much longer time horizons that would lead to decisions inconsistent with societal behavior in other spheres; it also avoids a rapid increase in the implied value of time if horizons shorter than 100 years are used. Selection of a time horizon affects decisions on financial mechanisms and carbon credit. Simple adaptations can allow a time horizon to be specified and used to calculate mitigation benefits and at the same time reserve a given percentage of weight in decision making for generations beyond the end of the time horizon. The choice of a time horizon will heavily influence whether mitigation options such as avoided deforestation are considered viable.

Lightning protection is a modern development of innovation led by Benjamin Franklin: the electric rod. Today, lightning protection systems are being used on the launch pads of thousands of buildings, homes, factories, towers and even space shuttles. This article will examine why lightning protection is necessary and what systems can and cannot do. Components of a lightning protection system Electrical rods or 'air terminals' are only a small part of the entire electrical protection system. In fact, rods can play the least important role in any system installation. A lightning protection system consists of three main components: Rods or 'Air Terminals'-Small, vertical protrusion rods designed to act as a 'terminal' for a lightning discharge are available in a variety of shapes, sizes and designs. Most are topped with a long, pointed needle or a smooth, polished sphere. The effectiveness of different types of lightning rods and even the need for fully rods is the subject of much scientific debate. Conductor Cables-Heavy wires (on the right) that send lightning from the sticks to the ground. The wires are run at the top and around the edges of the roof, then one or more angles of a building go down to the ground rod (s) below. Ground Rods-Long, dense, heavy rods were buried deep in the earth around protected structures. Conductor cables are attached to these rods to complete the safe path for lightning around any structure. Conductor cables and ground rods are the most important components of an electrical protection system, carrying out the main purpose of safe current flow outside any structure. The "lightning rods" themselves, i.e. the main vertical-centered terminals along the edges of the roof, do not play much of a role in the efficiency of the system. Given a good protection setup, good cable coverage and good grounding, it will still work adequately without air terminals. Lightning protection systems-What they do and don't do The sole purpose of a lightning protection system is to ensure the safety of a building and its occupants from direct lightning strikes, a task that was accomplished by providing a good, safe way to follow lightning. Myth, in contrast to electrical protection systems:  Don't attract lightning  The storm of its charge cannot 'clear' the lightning  Most people do not provide protection for sensitive electronics  Provide fire protection and structural damage protection by preventing the hot, explosive power channel from passing through building materials. How a lightning protection system works

The Intergovernmental Panel on Climate Change (IPCC) provides convincing evidence of global warming as a result of increased greenhouse gas production. There has been a greater occurrence of extreme climate events in recent decades. We need to ensure that our buildings and infrastructure can cope with such events and possibly more extreme events in the future. A good grounding in unsaturated soil mechanics will be necessary to understand future changes involving the drying and desiccation of soils that will occur in dry seasons and the wetting and infiltration processes that prevail during wet seasons. To predict the impacts of climate change will require the use of robust numerical modelling of climate/soil interactions that can be used to model the effects of future climate regimes. To achieve this we need high quality field observations involving climate/soil interaction that can be used to validate the models. This paper reports on a study in the UK to acquire such data.

In 1928, in Leningrad, in the Grand conference hall of the Academy of Sciences of the USSR, the First evening of ‘Art of light and color’ was held, and the examples of the connection of music, dance, recitation and architecture with special lighting effects were demonstrated. The organizer of the unusual event was the artist Grigory Gidoni (1895–1937), who displayed the wide spectrum of possibilities, regarding the use of light and color equipment, invented by him. The article analyzes the documents that let us understand the place of Gidoni’s experiments among the similar projects of the first decades of the twentieth century and their significance for future developments. The article is based on materials from private and public archives of Russia and Lithuania.
В 1928 году в Ленинграде, в Большом конференц-зале Академии наук СССР, состоялся вечер, на котором были продемонстрированы примеры соединения музыки, хореографии, декламации и архитектуры с особым световым оформлением. Организатором необычного мероприятия выступал художник Григорий Гидони (1895–1937), представивший зрителям возможности изобретенной им свето-цветовой аппаратуры. Автор статьи анализирует документы, позволяющие понять место экспериментов Гидони в ряду аналогичных опытов первой трети ХХ века и их значение для последующего времени. Работа основана на материалах из частных и государственных архивов России и Литвы.

This paper describes how operational radar, satellite and lightning data may be used in conjunction with numerical weather model data to provide remote detection and diagnosis of atmospheric turbulence in and around thunderstorms. In-cloud turbulence is measured with the NEXRAD Turbulence Detection Algorithm (NTDA) using extensively qualitycontrolled, ground-based Doppler radar data. A real-time demonstration of the NTDA includes generation of a 3-D turbulence mosaic covering the CONUS east of the Rocky Mountains, a web-based display, and experimental uplinks of turbulence maps to en-route commercial aircraft. Near-cloud turbulence is inferred from thunderstorm morphology, intensity, growth rate and environment data provided by (1) satellite radiance measurements, rates of change, winds, and other derived features, (2) lightning strike measurements, (3) radar reflectivity measurements and (4) weather model data. These are combined via a machine learning technique trained using a database of in situ turbulence measurements from commercial aircraft to create a predictive model. This new capability is being developed under FAA and NASA funding to enhance current U.S. and international turbulence decision support systems, allowing rapid-update, highresolution, comprehensive assessments of atmospheric turbulence hazards for use by pilots, dispatchers, and air traffic controllers. It will also contribute to the comprehensive 4-D weather information database for NextGen.

Here the readers can find basics of modern lightning protection technologies and essentials of grounding technics inlcuyding products and other devices manufactured by ORBITAL Lightning Protection.

Here are the details of working schedule and sketchs of ORBITAL LightninG Terminals with its technical aspects.

More cites and information for https://orbitaltechs.com

Legal liability is an issue that concerns volunteer firefighters and may affect the ability of fire managers to perform their tasks. There are calls to guarantee firefighters will not be personally liable for actions undertaken in good faith. This paper reviews post-wildfire litigation in Australia and claims for compensation made against the New South Wales Rural Fire Service. Although the data are incomplete and likely to underestimate the actual claims history, analysis of the available data does show that the number of claims for compensation is small given the very large number of fires and hazard reduction burns across Australia. There is no evidence of extensive post-fire litigation or of fire agencies or firefighters being held liable for actions taken in the course of firefighting The evidence does not support assertions that there is an ‘increasing flood’ of legal claims arising from firefighting. Post-fire litigation is compared with other proceeding such as Royal Commiss...

Lightning is a natural phenomenon in which large amounts of electricity are discharged from one location to another through open air, resulting in a bright arc of light. During an electrical storm, clouds begin to build up powerful electric fields, eventually ionizing the air around them and developing a powerful current. These areas, called step leaders, form paths of ionized air (or plasma) that slowly make their way toward the Earth. If a step leader makes contact with another ionized path, called a positive streamer, it creates a completed path for the plasma to travel on, allowing the accumulated current in the cloud to travel between the two points. This results in a lightning bolt and an explosion of air, which we call thunder. This project discusses the steps to design earthing and lightning protection system on building. The building is made strong and resistive against lightning strikes by making the building as negatively charged structure with use of cathodic protection materials and coatings. In addition, treating the problems that affects the structure gets reduced by lightning protection method which are determined by experiments and case studies.

For more information visit vaisala.com/lightning As a meteorological consultant and a university general science course instructor for many years, the authors have collected questions regarding lightning that are frequently asked by customers, students and friends. This booklet answers these questions and provides additional knowledge to help the readers understand basic lightning physics and lightning safety, as well as lightning detection.

Generally, lightning damage has mainly been to home appliances and telephones, Towers and power transmission and generation equipment mal functions and damage due to strikes on power lines. With the adoption of wind power generation equipment, however, lightning damage is also increasing in this area. Through his dimensional characteristics and the wind power system is more exposed in the nature of all others. Lightning damage is the single largest cause of unplanned downtime in wind turbines and that downtime is responsible for the loss of countless megawatts of power generation. Wind turbines are high structures and, like tall towers, they not only attract downward flashes but initiate upward flashes as well. The rotation of the blades may also trigger lightning and result in considerable increase in the number of strikes to a wind turbine unit. Since wind turbines are tall structures, the lightning currents that are injected by return strokes into the turbines will be affected by reflections at the top, at the bottom and at the junction of the blades with the static base of the turbine. We present in this study our contribution to study of the impact of direct and indirect lightning strokes on wind turbines.

Building's entrance is metaphorically a threshold between two realms, the first is an outdoor exposed to climatic change, hazards, and environmental factors, while the second is controlled, monitored, and determined to certain functions. It plays an important role in enriching users' experience. Moreover, it is the first impression a visitor takes to evaluate a whole building. Architecturally, the entrance is a very special part in the elevation, distinguished and emphasized by different design approaches. One of these approaches is using lighting. There is a direct connection between recognition of a space and light assimilation in it. From sunset to dawn, the artificial lighting plays a role in drawing attention to texture, colours, and forms of external elevations, which supports architecture to achieve its purpose. This paper sheds the light on the problem of architects' failure to manage an entrance perception due to insufficient light integration, over illumination, or weak transition from space to another. Many architects consider the entrance as a challenging task, because they believe that it has a direct impact on visitors' perception. This paper, therefore, aims to propose design methods to emphasize the entrance of buildings at night through using the proper artificial lighting. To achieve this aim, the paper used a scientific methodology, based on tracing literature review about design of entrances, investigating ideas of entrances' emphasis, and then analysing four case studies trying to identify the different design approaches of their entrances and how the location, direction, and intensity of illumination became a part of their nocturnal architectural elevation. As a conclusion, techniques of lighting entrances contribute in perceiving architecture’s true purpose and raise the aesthetic dimension of the building at night.

A high luminance contrast between windows and surrounding surfaces can increase the risk of discomfort glare, which can diminish office workers' satisfaction and productivity. Accordingly, it can lead to occupant interventions, such as drawing window blinds or increasing electric light levels, which are intended to enhance indoor visual comfort but counterproductively act to increase energy consumption. Increasing the luminance of the areas surrounding the windows using a supplementary lighting system, such as wall-washing with light emitting diode (LED) linear luminaires, could reduce discomfort glare arising from windowed walls. This paper reports on the results of a study in a typical office room in Brisbane, Australia. The outcomes of this study indicate that creating a luminance contrast of between 11:1 and 12:1 on the window wall in an office room with a 45% window-to-exterior-wall ratio using a supplementary LED system leads to improved subjective assessments of window appearance. The results suggest that such an enhancement could significantly reduce discomfort glare from windows, as well as diminishing the likelihood of the users intending to turn on the ceiling lights or to move the blinds.