Striking Distance Research Articles

Notes from the Editors, September 2024

This month's "Notes form the Editors" recounts the history of U.S. preparations for "prolonged and limited" nuclear war and Washington's repeated refusal to abide by international agreements regarding nuclear weaponry. With the recent announcement that the United States will be stationing nuclear-capable Tomahawk missiles on German soil—within minutes' striking distance of Moscow—this history is now, troublingly, more relevant than ever.

Attachment processes of negative flashes with multiple return strokes to a tall tower observed at close distances

Two downward negative flashes (F1612 & F1613) with multiple return strokes struck to the 356-m Shenzhen Tower were analyzed. The high-speed camera captured upward positive connecting leaders (UCL) for the first strokes of both flashes and two subsequent strokes of F1612. The observations also show that none of the downward negative leader (DNL) completely propagated to the tower tip before the occurrence of the return stroke (RS), so that we inferred that the UCL initiated from the tower tip might exist for each RS of the two flashes. The possible height of the UCL and DNL connecting point above the tower tip for each RS was estimated, which showed a positive correlation to the speed of corresponding DNL. The striking distances estimated for 8 subsequent RSs in F1612 were in a range from 14.6 m to 85.4 m and that for 3 subsequent RSs in F1613 were from 24.2 m to 66.2 m. There was a weak positive linear relationship between the DNL speed and striking distance for subsequent RSs in the two flashes. The DNL speed showed a positive correlation to the peak current of corresponding RS.

Investigation of Upward Leader Development Characteristics by Two Kinds of Charge Density Models in Wind Turbines

ABSTRACTThe upward discharge is a significant factor threatening the operation of wind farms. This paper investigates the inception and development of upward leaders of wind turbines' tip, where blade rotation prevents charge accumulation, using charge density models from laboratory discharges and artificially triggered lightning. The results indicate that larger return stroke currents create higher spatial potentials, and slower downward leader speeds allow for longer development time, favoring the development of upward leaders. As wind turbine sizes increase, the rotation of the blade tips resembles artificially triggered lightning, and the long air gap discharge model may underestimate the development of upward leaders. Calculations from the artificially triggered lightning model reveal improved upward leader formation when further laterally away from the downward leader within a certain distance, elucidating why multiple upward leaders are frequently observed around turbines. The striking distance and attractive radius are largely determined by the development of upward leaders. The absence of corona charge shielding at blade tips means upward leader inception is independent of downward leader velocity, emphasizing downward leaders' significant influence on turbines. Thus, the formula for estimating a wind turbine's lightning incidence requires integrating the return stroke current and velocity of the downward leader.

Comparative Mitogenome Characterization of Cryptic Asian Seabass (Lates calcarifer) in Captivity within Peninsular Malaysia

Lates calcarifer is one of the most commercial species in the world. Yet, phylogenetic relationships among this cryptic species remain unclear despite its significance in the fishery sector. The first report on bifurcation of captive Lates calcarifer in Peninsular Malaysia (PM) inferred from complete mitochondrial genome was discussed in the present study. Two mitochondrial genomes (mitogenomes) of Lates species were sequenced and assembled. The mitogenome length was 16,627 bp and 16,515 bp for K4 and S15, respectively. The majority of PCGs in both species exhibited the common initiation marker ATG codon and ended with termination marker TAA codon. Also, the incomplete termination codon T/TA was found in both species. Most AT-skew and GC-skew values observed in the protein-coding genes (PCGs) across the two samples were negative. The phylogenetic analysis based on 13 protein-coding genes by Maximum-Likelihood tree displayed two lineages from different regions which were from Myanmar/Indian waters (K4) and Southeast Asia/ Australian waters (S15). The striking genetic distance values between both specimens indicated 13 PCGs were suffering purifying selection. This study offers significant information for future analyses of evolutionary relationships among the numerous and taxonomically puzzling perciform fishes.

Buchdahl-inspired spacetimes and wormholes: Unearthing Hans Buchdahl’s other “hidden” treasure trove

Circa 1962 Hans A. Buchdahl pioneered a program — and made significant progress — seeking vacuo configurations in pure [Formula: see text] gravity (H. A. Buchdahl, Nuovo Cimento 23 (1962) 141). Unfortunately, he deemed the final step in his calculations impassable and prematurely suspended his pursuit. Since then, his achievements on this front have faded into dormancy. Unbeknownst to Buchdahl himself, the [Formula: see text] vacua that he sought were within his striking distance. In our recent three-paper body of work published in Nguyen (Phys. Rev. D 106 (2022) 104004; Phys. Rev. D 107 (2023) 104008; Phys. Rev. D 107 (2023) 104009), we broke this six-decades-old impasse and accomplished his goal: A novel class of metrics, describing non-Schwarzschild spacetimes in quadratic gravity and carrying a hallmark of higher-derivative characteristic. Intriguing properties of Buchdahl-inspired spacetimes and their associated Morris–Thorne–Buchdahl wormholes — summarized herein — embody a new branch of phenomenology that transcends the Einstein–Hilbert paradigm. May this unsung legacy of Hans A. Buchdahl long “forsaken” and “forgotten” finally live on Our essay is a passageway bridging the past and the future. The past is rooted in a research program originated but left unfinished by Buchdahl going back threescore years ago. The future is the new horizons his program brings forth. In between is our labor — summarized in a three-installment “Beyond Schwarzschild–de Sitter spacetimes” series[1–3] — to advance the Buchdahl program and achieve his ultimate goal.

Notes from the Editors, May 2023

This month, MR editors examine elements of the New Cold War rarely discussed in the mainstream media: the U.S. sabotage of the Nord Stream pipeline, which ensured Europe's continued reliance on U.S. natural gas, and U.S. plans to transport B61-12 nuclear warheads to locations within striking distance of Russian targets.

Research on Communication Stability of Inter-Cannonball Network Based on OPNET

In modern warfare, achieving strikes against military targets commonly involves utilizing methods such as fire coverage and missile precision guidance. While effective, fire coverage requires significant ammunition support, and missiles can be costly. Therefore, an intelligent strike solution can be an effective way to address these challenges. The inter-cannonball wireless communication network provides a solid foundation for inter-cannonball networking and joint strikes. The synergy improves the strike’s range and precision, ensuring own safety and destroying the enemy’s core with success. In this paper, the reliability of inter-cannonball group communication is studied. The vast array of activities and short striking distance of cannonballs make wireless networking between cannonballs a technological challenge. For this unique communication environment, the network of cannonballs is discussed, the self-organizing structure model of the network is proposed, the corresponding node topology is established, the protocol framework of inter-cannonball communication is presented, and the simulation parameters of the communication network are set. On this premise, discrete event simulation is performed by using the OPNET program to validate the impact of failure rate and node movement speed on the inter-cannonball network communication reliability. And the main performance indices of the inter-cannonball communication system are derived. The simulation results indicate that it can maintain basic communication stability, with wireless LAN delays of less than 100 ms, even when the node failure rate reaches 20%. The simulation verification method, on the other hand, overcomes the limitations of the real environment, optimizes the design phase, reduces research costs, and accelerates the development of intelligent cannonballs.

Lessons Learned: Surveying the Practicality of Differential Privacy in the Industry

Since its introduction in 2006, differential privacy has emerged as a predominant statistical tool for quantifying data privacy in academic works. Yet despite the plethora of research and open-source utilities that have accompanied its rise, with limited exceptions, differential privacy has failed to achieve widespread adoption in the enterprise domain. Our study aims to shed light on the fundamental causes underlying this academic-industrial utilization gap through detailed interviews of 24 privacy practitioners across 9 major companies. We analyze the results of our survey to provide key findings and suggestions for companies striving to improve privacy protection in their data workflows and highlight the necessary and missing requirements of existing differential privacy tools, with the goal of guiding researchers working towards the broader adoption of differential privacy. Our findings indicate that analysts suffer from lengthy bureaucratic processes for requesting access to sensitive data, yet once granted, only scarcely-enforced privacy policies stand between rogue practitioners and misuse of private information. We thus argue that differential privacy can significantly improve the processes of requesting and conducting data exploration across silos, and conclude that with a few of the improvements suggested herein, the practical use of differential privacy across the enterprise is within striking distance.

Time-Domain Analysis of the Impact of Advanced Building Construction Materials on the Propagation of Lightning Electromagnetic Field and Its Mitigation Using Nanoforging

The comprehension of the propagation characteristics of lightning electromagnetic field (LEMF) is essential to inspect the impact of nearby lightning strike and its coupling effect on different systems and equipment. Undeniably, the presence of building structures alters LEMF reaching any point of installation of critical equipment. In this regard, this article attempts a complete time-domain analysis of the influence of building structures on LEMF propagation at near and far striking distance. The influence of aperture location on structures with respect to the direction of LEMF propagation is quantified first ever. The LEMF penetration capability of novel constructional materials, namely carbon nanotube (CNT)-forged concrete and glass fiber-reinforced gypsum, is compared to that of concrete, and surface charge estimation methodology is adopted for the first time to quantify the plausible LEMF shielding performance. It is observed that the presence of apertures influences the LEMF distribution, but their location has inconsequential effect. Among the materials, CNT-forged concrete offers nearly 2 dB of electric field attenuation and 10 dB in energy penetration due to LEMF, quantifying the field mitigation effect due to nanoforging. Experimental study confirms better shielding performance of nanocompounded concrete. For magnetic field, the presence of apertures and the type of construction material do not deliver a sizable effect.

Quantitative characteristics of the striking distance to wind turbine blades based on an improved stochastic lightning model

AbstractThe damage of wind turbines suffered from lightning strikes has been a key issue for the safe and reliable operation of wind farms. Accurate determination of the annual lightning flash number to a wind turbine is essential for designing proper lightning protection measures. The interaction of downward and multiple upward leaders (MULs) is studied in this paper, which also considers the stochastic nature and branched behaviour of the lightning attachment phenomenon. Firstly, with an improved stochastic lightning model, the relationship among the striking distance, the height of wind turbines and the return stroke current is established. Moreover, a modified method for predicting the annual lightning flash number strikes to a wind turbine is proposed. The simulation results show that the striking distance and the collection area not only depend on the return stroke current, but also on the height and blade angle. Besides, the comparations between the calculation results and field statistics indicate that the conventional electric geometry model is not satisfied with the need of lightning protection for wind turbines. Note that there is only a difference of 4% between the modified method and the observation value. These quantitative researches provide the guidance of calculation results for the optimization of the blade lightning protection system (LPS) design.

The IRA Is an Invitation to Organizers

The Inflation Reduction Act would not have happened without the movement for a Green New Deal, but it shouldn’t be confused for one. The climate left (broadly defined) now faces a novel problem: how to deal with having won something—and keep fighting for more. It’s understandably hard for those who supported Green New Deal proposals for transformative investments in public goods to see the IRA—a bundle of tax credits whose benefits accrue largely to corporations—as a consolation prize. For the many climate hawks galvanized by Bernie Sanders’s bid for the Democratic nomination in 2020, it’s also a far cry from what, for a moment, looked to be within striking distance: governing power.

APLICAÇÃO DA BIOMECÂNICA ESPORTIVA NA ANÁLISE TÉCNICA DO CHUTE NO TAEKWONDO

ABSTRACT Introduction: With the gradual improvement of the theoretical system of sports biomechanics and the high requirements of Taekwondo development, the scientific research of Taekwondo is no longer restricted to a monothematic perspective; sports biomechanics is a combination of the complex forms of movement and body changes in the sport, a discipline that combines the principles of mechanics and biology for research. This discipline, allied to the study of sport, contributes to the correct understanding, training, and mastery of movement techniques. Objective: Apply a technical analysis of the taekwondo kick through a sports biomechanics approach. Methods: Using a three-dimensional kinematic motion capture system, volunteers of 58kg, 68kg, 80kg, and three other weight classes, in a total of 30 athletes, participated in this research. The movements included technical kicks and the collection of motion trajectories when hitting the target. Results: There were significant differences in the angle, angular velocity, torque, action time, displacement, and velocity of the lower limb joints of the three weight classes (P<0.05). Conclusion: The higher the athlete’s weight, the lower the body agility; although the striking distance is relatively long, the impact on movement speed is relatively minor. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Modeling the lightning-channel formation based on the bipolar leader theory by an electrostatic-by-step approach allowing representing non-regular ground surfaces for applications related to lightning protection

• Model of lightning-channel formation in negative cloud-to-ground flashes. • Simulation of the lightning channel formation using bidirectional leader theory. • Estimating the Striking Distance using the bipolar leader model. • Estimating the Striking Distance for ground objects over non-uniform ground. • Threshold electric field for initiation of upward leader from ground structures. A model for simulating the process of formation of the lighting channel in negative cloud-to-ground lightning, based on the bidirectional leader theory that allows calculating the evolution of the involved electrical quantities is presented. In particular, a new approach for modeling the effect of the ground by means of surface charges was included and substantially improved the quality of the model results. The tool that implemented the model was applied for developing certain results, including the threshold electric-field intensity required for initiation of the upward connecting leader from ground structures and estimates of striking distances. The striking-distance results tend to be consistent with those provided by expressions based on observations of the real leaders with fast cameras, when their three-dimensional and inclined trajectories are considered.

Lightning attachment characteristic of wind turbine generator: Experimental investigation and prediction method based on simulations

AbstractAs the height of wind turbine increases, the lightning strike accident has become a non‐negligible issue. In this paper, the lightning attachment characteristic of a 2‐MW wind turbine generator (WTG) is investigated using a model with a reduced scale of 100. The WTG model is equipped with receptors on the blades and a lightning rod on the nacelle, both serving as its external lightning protection system (LPS). The high‐voltage electrode, which delivers a lightning impulse voltage from a Marx generator, is used to simulate the final stage of downward negative lightning strikes from 29 coming‐leader positions. The experimental results indicate that lightning leaders from either front directions or side directions could be intercepted effectively by LPS, whereas the back‐direction lightning could not. Moreover, with the increase of striking distance, the capture ratio for the insulation part of blade decreases. Electric field intensity distribution simulations for the full‐scale WTG model, using conditions similar to their experimental counterparts, are conducted and compared with the lightning attachment distribution. Based on classical electro‐geometrical model, a simulative method is proposed to predict the lightning attachment distribution of WTG. Our results indicate that it is feasible with this method to produce a satisfactory approximation to the experimentally obtained lightning attachment distribution.

A Value Approach for Home Buyers in Township Projects

Abstract: The last two decades have witnessed hectic real estate activity especially the proliferation of residential townships. Not only the metropolitans but even the mid-sized cities have adopted the apartment or commonly called the flat system of housing. The twenty-first-century house buyer wants to be in the vicinity of Malls, entertainment places, shopping areas, and gyms. Almost every middle-class household owns a car and many of them have more than one, yet want near to the workplace, education institutions, and hospitals as also a striking distance from Airport, etc. Real estate works in micro markets and the cost of apartments normally is talked about in cost/sqft. The house buyer has a set of requirements to be met in a given budget but he gets to hear and talked about huge claims, jargons, and fuzzy cost calculations. Thus, one is neither clear about the overall amenities, nor the square feet and not even the total cost quoted by different builders at the decision-making time. This paper presents enlistment of quality-of-life parameters as identified from the literature survey and the survey. Further, a Value Approach is presented that could be used for rating real estate products based on the parameters that directly impinge on the QOL (Quality of Life) of the homebuyer and the value he or she places on them

The performance during four stationary knife attacks: Implications for tactical training

With over 72,000 offenses between 2010 and 2020 in the USA, knives were the third most commonly used weapon in all violent crimes between behind personal weapons and handguns. PurposeExamine the performance of different stab (Thrust and overhead) and slash (Figure 8 and Reverse) knife motions to determine how long it takes to execute each motion. In addition, examine the variability in executing each motion to inform future self-defense strategies. MethodsTwenty subjects (Females, n = 4; Males, n = 16; Height: 179.96 ± 8.66 cm; Weight: 94.99 ± 22.37 kg; Age: 36.95 ± 10.63 years) who were all active-duty law enforcement officers (LEOs) with 13.52 ± 11.23 years of LEO experience were recruited to participate in the study. Each subject completed two trials of the knife motions while wearing wearable motion sensors (ADPM) and recorded with a high-speed camera (GoPro) while using a training knife (Cold Steel). ResultsThe time to complete the motions were: Thrust, 0.61 ± 0.15 s; Overhead, 0.68 ± 0.14 s; Figure 8, 1.07 ± 0.21 s; and Reverse, 0.62 ± 0.11 s. The Figure 8 motion was significantly slower than the other three motions: F (3, 57) = 101.19, p < 0.001, ηp2 = 0.84. The reliability analysis reported trivial variability and a high level of agreement: Thrust, ICCα = 0.701, SEM = 0.09 s, CV% = 15.02; Overhead, ICCα = 0.878, SEM = 0.05 s, CV% = 6.93; Figure 8, ICCα = 0.906, SEM = 0.07 s, CV% = 6.25, Reverse, ICCα = 0.420, SEM = 0.10 s, CV% = 17.31. DiscussionMost LEOs or civilians within striking distance of someone with a knife may not be able to avoid contact from the knife attacks based on the speed knife attacks could occur. ConclusionThe reference data provides pertinent information to update evidence-based training approaches to knife attack preparation and defense.

Dead Children, Resilience, and Diversity

Dead Children, Resilience, and Diversity

DAP5 Binding to the FGF‐9 mRNA 5’ UTR is Structurally‐Dependent

Eukaryotic mRNA translation is typically modulated by eukaryotic initiation factor 4E (eIF4E) binding to the 5’‐m7G cap. However, under the hypoxic conditions within the cancer cell, eIF4E is segregated by 4E binding protein. Thus, cap‐independent recruitment of the 40S ribosome to the 5’ untranslated region (5’ UTR) of the mRNA is required for tumorigenesis. Fibroblast growth factor 9 (FGF‐9) is one such angiogenic growth factor upregulated in a cap‐independent manner in breast and colorectal cancer cells. Previously, our lab has demonstrated that binding of death‐associated factor 5 (DAP5), a eukaryotic initiation factor, to the FGF‐9 5’ UTR directly impacts cap‐independent translational efficiency. However, the exact binding site of DAP5 within the 5’ UTR is unknown. RNA secondary and tertiary structure within non‐coding regions has been demonstrated to play a role in cap‐independent translational efficiency; therefore, we hypothesized that specific structures act as eukaryotic initiation factor binding sites. Using SHAPE‐sequencing data, we reveal that the 5’ UTR of FGF‐9 is highly structured and possesses a single‐stranded region near the start codon. Through SHAPE footprinting and toeprinting experiments, we also demonstrate that DAP5 binds along a single face of the FGF‐9 5’ UTR and contacts the 3’ single‐stranded region. Our lab had previously reported that cap‐independent translation of FGF‐9 does not require a free 5’ end, suggesting little to no ribosomal scanning for the start codon occurs. Our current data demonstrate that initiation factor binding is structurally‐dependent and suggest that limited ribosomal scanning is due to DAP5‐dependent restructuring of the 5’ UTR to bring the start codon within striking distance of the 40S ribosome. We are currently examining whether cap‐independent upregulation of other tumorigenic transcripts follows a similar pattern.

Improving the computational accuracy of the dynamic electro-geometrical model using numerical solutions

The dynamic electro-geometrical model has been applied in various studies to investigate the probability of a lightning strike to parts of a structure. The numerical computation of the dynamic electro-geometrical model (DEGM) follows an iterative step by determining lightning strike points from above to a point on a structure of interest. This computation is often time-consuming and requires extensive computational resources. This study delves into the inner workings of DEGM striking distance computation. It highlights sources of computational numerical errors, such as the effect of the discretisation size. It proposes ways to eliminate such by using a conversion factor while also significantly reducing computation time from more than 14 h to approximately 6 min for a cuboid structure by eliminating ground surface points. The performance of the proposed improved DEGM (IDEGM) was investigated using a floating roof tank and a cuboid structure with a central air termination, and an interception efficiency of 61% was achieved. An alternative case using catenary wires with a total lightning interception efficiency of 99.1% was also implemented. The percentage strike probability for the cases considered shows a close approximation to published results, and this confirms the accuracy of the implemented model. The IDEGM has the benefit of generating results with a significantly reduced computation time of just a few minutes as compared to several hours in previous models.

Improved Electrogeometric Model of UHV Transmission Line Based on Long Gap Discharge and Its Application

Based on long air gap discharge test data and lightning return stroke observation data, an improved electrogeometric model (EGM) considering terrain conditions is established and verified to analyze the lightning shielding performance of UHV transmission lines. The striking distance formula is modified as rs = 0.13 (I2 + 40I)0.814. In this paper, the lightning shielding failure rate of three-phase conductors of EHV and UHV transmission lines calculated by the improved EGM model is consistent with the lightning observation data of actual transmission lines in Japan and the scaled lightning discharge simulation experimental results of UHV transmission lines in plains and mountainous areas of China, which verifies the applicability of the improved EGM model to evaluate the lightning shielding performance of large-scale UHV transmission lines. The improved EGM model is applied to evaluate the influence of tower type and slope steepness on the shielding failure tripping rate of UHV transmission lines. The shielding failure tripping rate of the SZ322 tower is higher than that of the SZT1 tower, and the shielding failure tripping rate of UHV transmission lines is greatly affected by slope gradient and increases with the increase of slope gradient.