Lightning

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...

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 ...

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. ...

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...

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 ...

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.

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.

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.

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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.

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.