Large Enclosure Research Articles

Numerical Evaluation of Aluminum-faced Sandwich Panels in Large Enclosure Fires

Numerical Evaluation of Aluminum-faced Sandwich Panels in Large Enclosure Fires

Post-release dispersal and home range of translocated red deer in the Vojvodina province (Serbia)

Monitoring of 38 (12 male and 26 female) red deer translocated from Ivo Wildlife Park (Romania) to hunting ground "Bosutske Forest" (Vojvodina, Serbia) was conducted from 2017 to 2021. The red deer were translocated in lieu of the managing authority's efforts to counteract the effects of red deer losses due to catastrophic flooding in the region. All animals were ear-tagged, while 7 males and 10 females were fitted with GPS collars. A total of 2,288 valid signals were analyzed (565 from males and 1,723 from females). In addition, 1,333 sighting records were collected from eight observation posts (480 in 2019, 670 in 2020 and 183 in 2021). We determined the movements and spatial distribution of translocated animals in the new habitat and estimated their home range sizes. Home range was calculated using the minimum convex polygon method, while the core area was calculated using the kernel density estimator method. The greatest straight-line distance from the acclimatisation enclosure was essentially the same for both sexes (average 6.0 km for males and 6.4 km for females). A non-significant relationship existed between the number of days in captivity and the greatest straight-line distance, as well as between days in captivity and the core area of the home range. The estimated home range of males was 12.8 km2 (range 0.2‒36.1), smaller than that of females (20.6 km2, range 0.4‒68.7), but this difference was not statistically significant. Observations made independently showed mostly herds of 4 to 6 individuals (52.3%), while large herds (≥ 10 individuals) were rare. Participation of translocated and resident animals in mixed herds was common during the monitoring period (62.3%). Our results showed that a high level of acceptance of the new habitat and social cohesion between translocated and resident animals was achieved. We believe that this is due to two main reasons: firstly, the long-term stay in a large acclimatisation enclosure prior to release and secondly, year-round supplemental feeding coupled with an abundant natural food supply in this unique forest area also contributed to successful acclimatisation. Keywords: Cervus elaphus; population; habitat; home range size; red deer; management

Morph-linked variation in female pheromone signalling and male response in a polymorphic moth.

Understanding the maintenance of genetic variation in reproductive strategies and polymorphisms in the wild requires a comprehensive examination of the complex interactions between genetic basis, behaviour and environmental factors. We tested the association between three colour genotypes and variation in female pheromone signalling and male antennal morphology in the wood tiger moth (Arctia plantaginis). These moths have genetically determined white (WW, Wy) and yellow (yy) hindwings that are linked to mating success and fitness, with heterozygotes (Wy) having an advantage. We hypothesized that attractiveness and reproductive success are correlated, with Wy females being more attractive than the other two genotypes which could contribute to maintaining the polymorphism. Female attractiveness was tested by baiting traps with females of the three colour genotypes both in low- (i.e. field set-up) and in high-population density (i.e. large enclosure set-up). Male's ability to reach females was correlated to their own colour genotype and antennal morphology (length, area and lamellae count). Contrary to our prediction, morph-related reproductive success and attractiveness were not correlated. Heavier Wy females attracted a lower proportion of males compared to WW and yy females. Specifically, an increase in weight corresponded to a decreased Wy but increased yy female attractiveness. yy females were generally more attractive than others likely due to earlier pheromone release. In males, lamellae count and genetic colour morph were linked to the male's ability to locate females. Furthermore, male traits affected their ability to reach females in a context-specific way. Males with denser antennae (i.e. higher lamellae count) and white males reached the females faster than yellows in the enclosure, while yellow males located females faster than whites in the field. Our results indicate that higher yy female attractiveness was likely affected by the combined effect of early pheromone release, female weight and higher population density. Males' searching success was affected by morph-specific behavioural strategies and local population density. Ultimately, the combined effect of genotype-related pheromone signalling strategies of females together with environment-dependent male behaviour affect male response and potentially contribute to maintaining variation in fitness-related traits.

Individual or communal? Exploring the social dynamics of ceramic production at the Lengyel circular-enclosure site of Těšetice-Kyjovice – Sutny, South Moravia

Although ceramic vessels form the majority of artifact assemblages in the Neolithic, little is known about their production beyond the assumption that they were made in a domestic context. Characterizing the scale of ceramic production is important for understanding Neolithic social and economic processes, particularly at sites with enclosure systems that indicate an increased degree of social organization. Nevertheless, characterizing the complexity and social entanglements of ceramic production is a difficult task in the absence of primary production locales.In this study, we provide a working hypothesis and use ceramic and clay petrographic data to highlight the variability in ceramic technological practices, and in turn, identify the organization of ceramic production at the Late Neolithic (Lengyel I; 4750–4500 BCE) site of Těšetice-Kyjovice – Sutny, South Moravia, Czech Republic. The site is characterised by a large circular enclosure, the construction of which required a high level of social cooperation. It is still under scrutiny whether the cooperation required for building the enclosure system was only temporary and related to this construction activity, or if it reflects a higher degree of social organization in general.By understanding ceramic production, we may clarify the complexity of the most common production processes that took place at the site. Large-scale ceramic and clay petrographic data provide information on the first steps of the chaîne opératoire in ceramic fabrication, which can be used to assess the organization of production. A systematic analysis of a large number of ceramic samples, representing all basic typological and macroscopically distinguishable fabric groups, revealed a high degree of individuality in choices of raw materials and tempers. Ceramic petrographic data, compared with the petrographic data of local sediment sources, further highlighted individuality in raw material and temper preferences, and even mixing of raw materials was identified.Our analyses suggest that Lengyel culture potters likely produced their vessels on a household level, with no evidence suggesting non-domestic production. These data, in conjunction with ceramic petrographic data from Hungarian Late Neolithic sites, suggest that Late Neolithic communities were self-sufficient in terms of utilitarian pottery production. Ceramic petrographic data also indicate interaction between the inhabitants of Těšetice and other Lengyel culture communities in the vicinity, perhaps further indicating a higher degree of social organization at the site.

High-Fidelity Simulation of the Light-to-Dense Stratification Transient in the HiRJET Facility

Density stratification in a large enclosure is a crucial phenomenon to heat transfer and sustainable passive heat removal of a sodium fast reactor during reactivity transients. However, engineering turbulence models were identified to have unsatisfactory performance in predicting propagation of a stratified front. Yet, the scarcity of high-resolution data for stratification hampers the development of models. To explor e applications of leveraging direct numerical simulation (DNS) data to support turbulence model development, this work conducted DNS using NekRS to study a long stratification transient in the High-Resolution Jet (HiRJET) experimental facility. This work considers an experiment run where light fluid is injected into a tank containing a denser fluid with a relative density difference of 1.5%. Formation of the stratified layer is identified as impingement of the buoyant jet promoting mixing of the two fluids. Based on the transient statistics, transport of the concentration can be characterized by regions with dominating effects of turbulent mixing, buoyant dissipation, and molecular diffusion, respectively, as moving away from the elevation of jet impingement. Concentration near the stratified front also exhibits oscillation at Brunt-Väisälä frequency. Preliminary validation of the simulation showed encouraging agreement of the concentration distribution with the reference experiment.

Pressure Behaviour of Hot Gases and Smoke in Fires of Large Enclosures with Different Ventilation Systems

This study investigates numerically the pressure behavior of hot gases and smoke in fires of large enclosures. It mainly covers the effectiveness of using natural and mechanical ventilation in changing the pressure behaviour of hot gases and smoke inside different structures. Fire Dynamics Simulator (FDS), provided by NIST, has been used to run the simulations for all proposed cases. For the assumed scenarios, the values of hot gas pressure and temperature are extracted at different points, especially in the hot layer close to the ceiling, for further analysis. The effect of changing the location of the fire source has been investigated, too. Final results show noticeable changes in the behavior of pressure, and temperature, in the presence of different ventilation systems, both natural and mechanical. Thus, appropriate ventilation systems can improve the pressure behaviour inside the place, which offers a better environment and higher safety level, in case of fire, in such large enclosures, open plan offices,

Memorial as aegis: Colonial sovereignty and the unmaking of the Kanpur Memorial Well Monument

This article addresses competing visions of sovereignty that underwrite recent debates about monuments. It turns to a well-known monument built to commemorate the loss of British lives in the Sepoy Rebellion of 1857–59: the Kanpur (Cawnpore) Memorial Well Monument. The memorial stood over a well in which the bodies of 200 British women and children killed by Indian sepoys lay buried. A large landscaped enclosure was built around the memorial and only European visitors were given access to the site. On August 15, 1947, the day of Indian independence from British rule, a crowd overran the site and defaced the monument. Much of the monument was subsequently dismantled and moved to a more secluded site within the Kanpur cantonment. The desire among the British stakeholders to leave no trace of its former identity focused attention on those aspects of meaning ascribed to the monument that could not be erased. Building on the Hobbesian idea of passion as a key element of sovereignty, this article argues that the monument may be viewed as an aegis — an apotropaion — that deflects gaze more than it enables attentive looking.

Lake browning counteracts cyanobacteria responses to nutrients: Evidence from phytoplankton dynamics in large enclosure experiments and comprehensive observational data.

Lakes worldwide are affected by multiple stressors, including climate change. This includes massive loading of both nutrients and humic substances to lakes during extreme weather events, which also may disrupt thermal stratification. Since multi-stressor effects vary widely in space and time, their combined ecological impacts remain difficult to predict. Therefore, we combined two consecutive large enclosure experiments with a comprehensive time-series and a broad-scale field survey to unravel the combined effects of storm-induced lake browning, nutrient enrichment and deep mixing on phytoplankton communities, focusing particularly on potentially toxic cyanobacterial blooms. The experimental results revealed that browning counteracted the stimulating effect of nutrients on phytoplankton and caused a shift from phototrophic cyanobacteria and chlorophytes to mixotrophic cryptophytes. Light limitation by browning was identified as the likely mechanism underlying this response. Deep-mixing increased microcystin concentrations in clear nutrient-enriched enclosures, caused by upwelling of a metalimnetic Planktothrix rubescens population. Monitoring data from a 25-year time-series of a eutrophic lake and from 588 northern European lakes corroborate the experimental results: Browning suppresses cyanobacteria in terms of both biovolume and proportion of the total phytoplankton biovolume. Both the experimental and observational results indicated a lower total phosphorus threshold for cyanobacterial bloom development in clearwater lakes (10-20 μg P L-1 ) than in humic lakes (20-30 μg P L-1 ). This finding provides management guidance for lakes receiving more nutrients and humic substances due to more frequent extreme weather events.

Husbandry and first record of captive breeding of the Asian giant river toad Phrynoidis asper

The Asian giant river toad Phrynoidis asper is a large species of bufonid from south-east Asia that is apparently obtained by the international exotic-pet trade from wild populations. Captive breeding of this species seems not to have been documented. The donation to Chester Zoo in October 2021 of an adult group of five males and one female of this toad species provided an opportunity to study captive breeding. The specimens were maintained separated by sex until signs of reproductive condition were apparent and then they were placed together in a large breeding enclosure. This had three distinct environmental zones simulating a riverbank. Six days after mixing the sexes a large spawn mass was laid. On hatching, the tadpoles were transferred to a rearing aquarium and then, after reaching Gosner stage 42, the developing toads were transferred to terrestrial vivaria to complete development. Captive breeding of this species could replace collection from the wild.

Improving the success of reinforcement programs: effects of a two-week confinement in a field enclosure on the anti-predator behaviour of captive-bred European hamsters.

Captive breeding programs are an important pillar in biodiversity conservation, aiming to prevent the extinction of threatened species. However, the establishment of self-sustaining populations in the wild through the release of captive-bred animals is often hampered by a high mortality upon release. In this study, we investigated how a 2-week confinement period within a large field enclosure affected the anti-predator behaviour of 'naive' captive-bred hamsters and how potential modifications persisted over time. During three consecutive tests, hamsters were confronted with a moving predator model (a red fox mount, Vulpes vulpes) and their behaviour was filmed. After the initial round of confrontation with the predator model, one group of hamsters (field group) was released into a field enclosure protected from predators, while the other group (control) remained in their individual laboratory cages. After 2 weeks, hamsters from the field group were recaptured and individuals of both groups underwent a second confrontation test. A total of 1 month after their return from the field enclosure, field hamsters were subjected to a last confrontation test. Video analysis, investigating four behavioural variables, revealed that field hamsters significantly modified their behavioural response following the 2 weeks confinement in the enclosure, while this was not the case for control hamsters. In addition, most behavioural modifications in field hamsters persisted over 1 month, while others started to revert. We suggest that an appropriate pre-release period inside a field enclosure will enable naive (captive-bred) hamsters to develop an adequate anti-predator behaviour that will increase their immediate survival probability upon release into the wild. We believe that such measure will be of great importance for hamster conservation programs.

Supplementing aerial drone surveys with biotelemetry data validates wildlife detection probabilities

Aerial drone systems are now widely used to survey wildlife, but validation in the detectability of individuals is rarely assessed. This knowledge gap is critical, given the influence of local environments on wildlife detectability from the air. In this study, we integrated Animal Biotelemetry technology with aerial drones to evaluate the temporal and environmental factors influencing animal detection probability and subsequent population estimates. Wild-caught feral pigs (Sus scrofa) were fitted with GPS tracking collars and releasing them into a large natural habitat enclosure in northern Australia. Utilizing a fixed-wing drone equipped with a dual camera (thermal infrared and RGB), we conducted multiple flights over the study area during both wet and dry seasons, from sunrise to sunset. The study found that the probability that a pig was visible in aerial imagery was highly variable depending on the timing of the aerial survey. Detection probability was at its lowest during mid-afternoon (5 to 20%), while the early evening yielded the highest detection probability (50 to 75%). We observed seasonal differences, with detection probabilities exceeding 50% in the mornings of the wet season, in contrast to less than 30% during the dry season. Temporal trends in detection probability were similar in both thermal infrared and RGB imagery. The GPS location data enabled us to assess how localized factors (canopy cover, land cover, ambient temperature) altered animal detection probability. This information facilitated the identification of survey times to maximize feral pig detection and the development of a correction factor to account for non-detected individuals at specific times and locations. The study demonstrates the value of integrating Animal Biotelemetry technology and aerial drones to account for variations in detection probability when undertaking wildlife aerial surveys. Insights gained from this approach have implications for enhancing the accuracy of population assessments and contributing to more effective wildlife management and conservation.

Study of Stable Stratification in HiRJET Facility With Direct Numerical Simulation

Stable density stratification in a large enclosure could significantly hamper the effectiveness of natural convection cooling in pool-type liquid metal or gas-cooled advanced reactors. In addition, accurate prediction of stratified front behavior remains to be a challenging task for turbulence modeling. With the rapid growth of high-performance-computing capabilities in recent years, conducting high-fidelity simulations for a large-timescale transient has become more affordable and hence a valuable data source to support turbulence modeling as well as to gain further physical insights. In this work, direct numerical simulation is performed at experiment-consistent conditions to simulate the density stratification transient High-Resolution Jet (HiRJET) facility. Specifically, we focus on the case where an injected aqueous sugar solution has 1.5% density higher than that in the enclosure. In the early stage of the transient, the impingement of the denser jet to the bottom surface of the enclosure promoted turbulent mixing locally. This rendered the establishment of the mixture layer, formation and swift upward propagation of the stratified front, and elevation with (locally) the highest vertical concentration gradient. As the front rose, the diminishing turbulent mass flux slowed down the propagation, and a larger vertical concentration gradient was established. In this stage, both the velocity and the concentration scalar showed large-timescale fluctuation behavior around the stratified front. For the concentration time signal, the characteristic frequency in the power spectral density was found to agree well with the Brunt-Väisällä frequency. The preliminary validation endeavor showed that the stratified front location and the corresponding concentration gradient magnitude in the simulation agreed well with the experiment data. Further validation will mainly revolve around benchmarking against high-resolution density measurement and high-order flow statistics.

High-Fidelity Simulation of Mixing Phenomena in Large Enclosures

In the present work, two large eddy simulations (LESs) of single isothermal jets discharging into large enclosure facilities are proposed. The geometries and tested flow conditions correspond to scaled experiments of the upper plenum of high-temperature gas-cooled reactors. More specifically, two reference experiments were conducted at Texas A&M University and Michigan University. The objective of the present work is to validate these simulations with their corresponding reference experiments. The proposed LES models are performed with NekRS, a spectral element code with graphics processing unit capabilities developed at Argonne National Laboratory. These simulations were performed on the Summit supercomputer at Oak Ridge National Laboratory. For validation purposes, first- and second-order statistics from the computational fluid dynamics (CFD) calculation are compared with measurements obtained from the experiments. The models proved to be accurate, as these results are in good agreement. Additionally, flow visualization is provided showing that these models are able to retrieve similar effects to what are described in the literature for this type of flow configuration. Finally, the proposed models are part of a broader effort under the current Integrated Research Project of Nuclear Energy Advanced Modeling and Simulation 1.1, whose main objective is to deliver fast-running models to accurately predict complex physical phenomena, including for instance, turbulent mixing and thermal stratification. In this regard, the CFD models proposed here will be used to generate a high-fidelity data set to be applied in conjunction with data-driven methods to improve turbulence modeling closures.

Iron Age and Roman Settlement at Land North of Newmarket Lane, Methley, Wakefield, West Yorkshire

Excavations to the southwest of Methley on a site to the north of the River Calder recorded an Iron Age settlement with possible Bronze Age origins, where a small community inhabited at least three phases of roundhouse within a large polygonal enclosure on the top of a hill overlooking the surrounding landscape. This was followed by Romano-British occupation during the mid to late second century AD and the mid third to early fifth century AD further to the south on the hill slope.

Two's company, three species is a crowd? A webcam-based study of the behavioural effects of mixed-species groupings in the wild and in the zoo.

Mixed species exhibits in zoos are used to create larger, more stimulating environments to support naturalistic interactions between species. In the wild, mixed species groups are observed as having lower rates of vigilance, presumably due to reduced predation risk through 'detection' and 'dilution' effects. This effect appears to be highly variable depending on factors such as food availability or degree of threat. This study aimed to collect data on mixed-species associations and consequent vigilance rates in the wild, collecting equivalent data from a large mixed-species zoo enclosure to compare the findings between free-ranging and captive populations. The study additionally investigated whether large mixed-species enclosures support natural associations and behaviours, by comparing the behaviour of captive animals with wild counterparts. The study used livestream video feeds from 10 national parks in South Africa and Kenya to observe free-ranging species, and a camera at the San Diego Zoo Safari Park's mixed species African exhibit. Scan and continuous sampling protocols were used simultaneously to record behavioural states as well as the rate of scanning (vigilance) events. GLMMs were run to test whether vigilance of a focal species varied according to the number of animals present, the density of animals in the group, and the diversity of species. In the wild, vigilance decreased with increasing number of animals in the surroundings but in captivity the group size had no impact. The results suggest that in the wild, these species benefit from increased perceived safety in larger groups, regardless of the species making up that group. No effect was noted in the zoo because of a reduced need for animals to show heightened vigilance to the same degree as in the wild. Similarities were observed in associations between species/mixed species group compositions, and in behaviour budgets. These findings provide a preliminary evaluation of how the impact of mixed species groupings may translate from the wild to the zoo, based on the associations and behaviour across a variety of African ungulates.

Experimental investigations of flow and thermal behavior of wall confluent jets as a heating device for large-space enclosures

The study aimed to explore the effects of inlet air temperature, outdoor air temperature, inlet bulk velocity, and the number of nozzles on wall confluent jets (WCJ) propagating along an external cold wall in a large space enclosure such as a greenhouse. A combination of experimental study and Response surface methodology has been used to predict the flow and thermal behavior of the WCJ for the studied cases. Box-Behnken design was used to determine the case matrix for four of the above-mentioned vital variables for non-isothermal cases. The experimental study employed constant current anemometers to measure the velocity and temperature of the WCJ. Results showed that the WCJ attached to the wall under both isothermal and non-isothermal conditions. This flow behavior suggests that the WCJ can be used to heat the external facades of large-space enclosures. All the stated variables were critical to the decay factor and decay rate of maximum velocity, albeit at varying levels. The velocity decayed faster with an increase in the inlet bulk velocity and outdoor air temperature. It also decayed faster as the number of nozzles and inlet air temperature decreased. The external wall surface temperature and the wall-heating effect increased as the momentum of the jet increased. The surface temperature on the external wall was most influenced by the inlet air temperature and least by the number of nozzles. Correlations of the second-order polynomial for the Response surface models that estimate the rate of velocity decay and temperature on the external wall were obtained.

Imaging Convective Phenomena inside Highly Refractive Cylindrical Enclosures

The conventional refractive index-based optical techniques show limitations in measuring the thermal field inside refractive surfaces due to the curvature effects. The present work reports on the application of lensless Fourier transform digital holographic interferometry for mapping heat transfer phenomena inside highly refracting axisymmetric enclosures. Experiments have been performed to characterize the buoyancy-driven natural convection heat transfer around a vertically oriented heated cylinder placed concentrically inside a relatively large cylindrical enclosure filled with de-ionized water. The experiments were performed under various heating conditions, and the corresponding holograms were analyzed in real-time to show the transients of the temperature field. Quantitative results were obtained in the form of a two-dimensional temperature distribution field and local heat transfer coefficients along the heated surface. Experimental results were validated by comparing the values of the surface temperatures obtained from the analysis with that obtained from the thermocouple data. The work presented highlights the ability of the lensless Fourier transform digital holographic technique to map the real-time temperature field inside a highly refracting enclosure.

Can native predators be used as a stepping stone to reduce prey naivety to novel predators?

AbstractPredator naivety negatively affects reintroduction success, and this threat is exacerbated when prey encounters predators with which they have had no evolutionary experience. While methods have been developed to inculcate fear into such predator-naïve individuals, none have been uniformly successful. Exposing ontogenetically- and evolutionary-naïve individuals first to native predators may be an effective stepping stone to improved responses to evolutionarily novel predators. We focused on greater bilbies (Macrotis lagotis) and capitalized on a multi-year mammalian recovery experiment whereby western quolls (Dasyurus geoffroii) were reintroduced into parts of a large fenced reserve that contained a population of naïve bilbies. We quantified a suite of anti-predator behaviors and measures of general wariness across quoll-exposed and quoll-naive bilby populations. We then translocated both quoll-exposed and quoll-naïve individuals into a large enclosure that contained feral cats (Felis catus) and monitored several behaviors. We found that bilbies can respond appropriately to quolls but found only limited support that experience with quolls better-prepared bilbies to respond to cats. Both populations of bilbies rapidly modified their behavior in a similar manner after their reintroduction to a novel environment. These results may have emerged due to insufficient prior exposure to quolls, inappropriate behavioral tests, or insufficient predation risk during cat exposure. Alternatively, quolls and cats are only distantly related and may not share sufficient similarities in their predatory cues or behavior to support such a learning transfer. Testing this stepping stone hypothesis with more closely related predator species and under higher predation risk would be informative.

Monitoring of Cortisol Levels in Hog Deer with Varying Environment Exposure

Hog deer (Axis porcinus) is one of the least studied animal species in Pakistan. It belongs to Order Artiodactyla and the family Cervidae. IUCN classified Axis porcinus as an endangered species in 2008. The present study was conducted to investigate the effects of varying environmental exposure, genders, and seasonal changes on captive hog deer (A. porcinus) at Lahore Zoo, Safari Zoo, and Jallo Park in Lahore, Pakistan. Non-invasive techniques were used to monitor stress levels in hog deer. For sample collection, four definite months belonging to two seasons’ winter and summer were considered. A total of 48 urine and faecal samples were collected from both male and female hog deer. Seasonal fluctuations have been found to have a significant impact on faecal and urinary cortisol levels. Higher cortisol levels were found in both male and female hog deer in the summer season at all three visited sites. Fluctuations in environmental exposure at three research sites had a significant impact on faecal and urinary cortisol levels. Higher levels of cortisol were found in both male and female hog deer at Jallo park and Lahore Zoo, as compared to Safari Zoo. It was concluded that lower cortisol levels at Safari Zoo might be due to better environmental conditions and more flexible enclosure size and interaction of various species of deer. Temperature affected hog deer cortisol levels in summer, as higher levels were measured in summer compared to winter. In addition, sex did not predict any stress levels in hog deer. It has been suggested that a large enclosure size can control levels of cortisol in hog deer.

On Modelling of Maximum Electromagnetic Field in Electrically Large Enclosures

Abstract The maximum electromagnetic field formed in the electrically large enclosures for a given input power has always been the focus of electromagnetic compatibility issues such as radiation sensitivity and shielding effectiveness. To model the maximums in a simple manner, the electrically large enclosure can be regarded as a reverberation chamber (RC), thus the generalized extreme value (GEV) theory based framework is used for both undermoded and overmoded frequencies. Since the mechanical stirrer is not easy to be installed like that for RC, frequency stirring and mechanical stirring related configurations are discussed, and the corresponding results have confirmed the validity of frequency stirring with the estimate of the parameters in GEV distribution. As for the maximum field, a comparison has been made between GEV distribution and IEC 61000-4-21, and the corresponding results have also highlighted that the maximum field can be assessed by frequency stirring configuration, and by GEV distribution with a desired confidence.