Characteristics of Regular Pulse Bursts Generated From Lightning Discharges

In this work, we studied the waveforms of all lightning discharges from about 15 min. Eighty-three percent of all lightning discharges contain particular waveforms called regular pulse bursts (RPBs), which have regular microsecond-scale electric or magnetic field pulses. Maximum proportion of RPBs occur in middle or rear of lightning discharges. Prior to or after RPBs, there is always a chaotic pulse period. The analysis indicated that RPBs are caused by a secondary discharge in the fractured old breakdown channel, likeness to dart-stepped leader occuring in negative cloud-to-ground discharge (-CG). Four types of RPBs, namely, category of normal RPBs, category of back RPBs, category of symmetric RPBs, and category of reversal RPBs, were sorted in the light of the evolution of the pulse amplitude, interval between neighboring pulses and pulse polarity. In addition, the difference between normal RPBs and back RPBs was considered to be caused by the distance between neighboring charge pockets and the magnitude of the charge in every charge pocket. The symmetric RPBs were considered to be caused by a discharge channel with a large central charge area. Reversal RPBs were considered to be caused by a bending channel or superposition of two or more RPBs. We located some RPBs in a typical intra-cloud flash (IC) in three-dimensional. The analysis showed that the developing velocity of RPBs ranged from approximately 1.2 × 106 m/s to 3.0 × 106 m/s, which slower less than both of the dart leader or dart-stepped leader process from previous studies. And we found it is several meters to dozens of meters that the lengths range of discharge step which between two adjacent pulses.

Description of a new species of Nannopus Brady, 1880 (Copepoda: Harpacticoida: Nannopodidae) from Argentinean waters, including an updated key to species

Both sexes of a new brackish-water species, Nannopus sinusalbi sp. nov. (Nannopodidae) are described from the Bahía Blanca estuary (38°53’S, 62°07’W) in Buenos Aires Province, Argentina. The only previous record of the genus in the study area was identified as the type species, Nannopus palustris Brady, 1880, with no description or illustrations, hence its authenticity cannot be confirmed. Nannopus brasiliensis Jakobi, 1956 is relegated to species inquirenda in the genus rather than being considered a junior synonym of the type species. Nomenclatural issues related to the usage of the alternative spellings Iliophilus Lilljeborg, 1902 and Ilyophilus sensu Sars (1909) and the unavailability of Ilyophilus canui Kim, Choi & Yoon, 2017 are discussed. An updated key to the 18 identifiable species of Nannopus (excluding the type species N. palustris) is presented. The harpacticoid assemblage at the type locality showed a distinct seasonality with N. sinusalbi sp. nov. representing about 8% of the community. The new species showed densities below 5 ind.cm‑2 during most of the year, reaching an abrupt peak of 40.17 ind.cm‑2 towards the end of the summer, when the maximum proportion of ovigerous females was recorded.

Physical and Chemical Fundamentals of Building the Structure of Dispersed Filled Polymer Composite Materials and Nanocomposites

Questions of the construction of dispersed structures of polymer composite materials using a generalized model of dispersed filled polymer composite materials (DFPCM) are studied. Using the parameter of maximum proportion of filler (φm) allows you to take into account the size, shape, and distribution of part of the dispersed filler at the same time. The transition to generalized and specified parameters when describing the structure of the DFPCM leads to the possibility of highlighting the optimal criteria for obtaining systems with the highest strength characteristics. The transition to generalized and reduced parameters when describing the structure of DFPCM leads to the possibility of selecting optimal criteria that ensure obtaining systems with the necessary level of rheological, electrochemical, physico-mechanical and other characteristics.

On the edit distance function of the random graph

Given a hereditary property of graphs $\mathcal{H}$ and a $p\in [0,1]$ , the edit distance function $\textrm{ed}_{\mathcal{H}}(p)$ is asymptotically the maximum proportion of edge additions plus edge deletions applied to a graph of edge density p sufficient to ensure that the resulting graph satisfies $\mathcal{H}$ . The edit distance function is directly related to other well-studied quantities such as the speed function for $\mathcal{H}$ and the $\mathcal{H}$ -chromatic number of a random graph. Let $\mathcal{H}$ be the property of forbidding an Erdős–Rényi random graph $F\sim \mathbb{G}(n_0,p_0)$ , and let $\varphi$ represent the golden ratio. In this paper, we show that if $p_0\in [1-1/\varphi,1/\varphi]$ , then a.a.s. as $n_0\to\infty$ , \begin{align*} {\textrm{ed}}_{\mathcal{H}}(p) = (1+o(1))\,\frac{2\log n_0}{n_0} \cdot\min\left\{ \frac{p}{-\log(1-p_0)}, \frac{1-p}{-\log p_0} \right\}. \end{align*} Moreover, this holds for $p\in [1/3,2/3]$ for any $p_0\in (0,1)$ . A primary tool in the proof is the categorization of p-core coloured regularity graphs in the range $p\in[1-1/\varphi,1/\varphi]$ . Such coloured regularity graphs must have the property that the non-grey edges form vertex-disjoint cliques.

Short-Term Traffic State Prediction Based on the Critical Road Selection Optimization in Transportation Networks

Short-term traffic prediction under corrupted or missing data for large-scale transportation networks has become an important and challenging topic in recent decades. Since the critical roads have predictive power on their adjacent roads, this paper proposes a novel hybrid short-term traffic state prediction method based on critical road selection optimization. First, the utility function of the quality of service (QoS) for the critical roads in a large-scale road network is proposed based on the coverage and the data score. Then, the critical road selection optimization model in the transportation networks is presented by selecting an appropriate set of critical roads with the maximum proportion of the total calculation resources to maximize the utility value of the QoS. Also, an innovative critical road selection method is introduced, which is considering the topological structure and the mobility of the urban road network. Subsequently, the traffic speed of the critical roads is regarded as the input of the convolutional long short-term memory neural network to predict the future traffic states of the entire network. Experiment results on the Beijing traffic network indicate that the proposed method outperforms prevailing DL approaches in the case of considering critical road sections.

Modeling the COVID-19 Vaccination Dynamics in the United States: An Estimation of Coverage Velocity and Carrying Capacity Based on Socio-demographic Vulnerability Indices in California

Introduction: Coronavirus disease 2019 (COVID-19) disparities among vulnerable populations are a paramount concern that extends to COVID-19 vaccine administration. We aim to better characterize the scope of vaccine inequity in California by comparing the Social Vulnerability Index (SVI) of California counties and respective vaccination rates, modeling the growth rate and anticipated maximum proportion of individuals vaccinated by SVI group. Methods: Overall SVI, its four themes, and 9228 data points of daily vaccination numbers across all 58 California counties were used to model, overall and by theme, growth velocity of proportion of population vaccinated and the expected maximum proportion of individuals (at least 1 dose of Pfizer-BioNTech, Moderna, or Johnson & Johnson/Janssen) that will be vaccinated for each theme. Results: Overall high vulnerability counties in California have lower vaccine coverage velocity compared to low and moderate vulnerability counties. The largest disparity in coverage velocity between low and highly vulnerable counties was observed in Theme 3 (minority status & language). However, our model showed that highly vulnerable counties based on Theme 3 are expected to eventually achieve a higher proportion of vaccinated individuals compared to low vulnerable counterparts if current trajectories continue. Counties in the overall low vulnerability category are estimated to achieve a higher proportion of vaccinated individuals when compared to high and moderate vulnerable counties, assuming current trajectories. The largest disparity in asymptotic proportion vaccinated between high and low vulnerable counties was observed in Theme 2 (household composition & disability). Conclusion: This study provides insight into the problem of COVID-19 vaccine disparity across California which can be used to help promote equity during the current pandemic as well as guide the allocation of future vaccines such as COVID-19 booster shots.

Improving the Quality and Durability of Restorative Coatings by Arc Deposition and Modification with Natural Additive Bentonite Clay

The study considers the possibility of improving the quality and service life of reducing coatings by arc deposition and modifying with natural additive bentonite clay. It has been established that when the modifier is introduced into the fluid bath during arc deposition, the phases and their interactions change. Introduction of the modifying additive bentonite clay significantly changes the crystalline lattice of the carbidephases. The optical-mathematical method revealed the absence of austenite and the pair interaction of ferrite-carbide during modification. The maximum proportion of phases corresponds to ferrite (33.8% -2 times decrease) and ferrite-austenite-carbide interaction (48.62% -2 times increase). The ferrite-austenite interaction increases almost 8 times during modification. The wear coefficient in this case is 2.2 times lower in comparison with the original steel 65Gand 1.4 times lower in relation to arc deposition with only T-620 electrode.

Effect of an axial-radial plate reactor modifications on a mega methanol plant production

Axial-radial flow plate reactors have been recently considered as efficient and practical types of reactors for methanol synthesis. Generally, an axial–radial reactor (AR) consists of two main parts namely the axial section and the radial section and the vast majority of the feed enters the radial section. Moreover, the structure of AR has a space above the axial part, which can add an adiabatic bed in the system. In this study, the performance of two novels AR configurations is investigated to improve the effectiveness of the axial–radial plate reactor. In the first configuration, the optimum length of the adiabatic bed is calculated and the adiabatic bed is located above the axial section inside the AR and is named IAAR. Therefore, in IAAR the feed of the axial section just enters the adiabatic bed and warms up. On the other configuration, the adiabatic bed with the optimum length is placed outside the reactor and is named OAAR. Therefore, in OAAR the total feed passes through the adiabatic bed, highly warms up, then cools to the optimum temperature in a heat exchanger, and finally enters AR. Two-dimensional mathematical modeling via orthogonal collocation on the finite element method is developed to compare the performance of two configurations. The results show that the maximum proportion of methanol produces in IAAR, which is approximately 3.8% higher than that produced in conventional AR due to utilizing an adiabatic bed inside the AR and superior gas distribution in the process. Momentum, mass, and heat equations are calculated and molar flow rates, mole fractions and temperatures are depicted along the radius and the length of the three configurations.

Mechanical Behaviour of Normal Concrete using Fibre of Pine Tree Needle Leaves

This research was carried out to study the behaviour of concrete, specifically flexural strength, by incorporating two types of pine needle leaves (green, and brown) recycled as fibre reinforcement in the concrete. The other goal of the study is to compare the two types of fibre and determine the maximum proportion of fibre to be added in the normal concrete. OPC concrete with 0%, 1% and 2% pine needle leaves fibre (green, and brown) was prepared based on the total weight of the mixture. At an ambient temperature of 28 ± 2°C, the specimens were checked for flexural strength (FS). Laboratory test results based on short term investigation reveals that the flexural strength of concrete containing brown pine fibre (BPF) is higher than that of Green pine fibre (GPF), and also higher than normal (OPC) concrete. The optimum proportion of pine needle leaf fibre is the brown fibre (fallen leaves) to be added in the concrete as fibre is 1% by the total weight of the mixture, which gave a positive reaction from the test that was performed.

POTENTIAL OF UTILIZATION OF ALLOCHTHONOUS INVERTEBRATES BY GAMMARUS KOREANUS UÉNO (AMPHIPODA)

In an isolating experiment on feeding only on arthropods of terrestrial origin, the potential of their consump-tion by amphipods from a fishless water-course is studied. The data obtained confirm the hypothesis that, on the basis of experiments on feeding exclusively on arthropods, it is possible to determine the maximum proportion of their biomass that selected consumers are able to utilize. The results of such works can be used to quantitative assessment of the level of possible losses of allochthonous matter and energy for the recipient communities of waterbodies due to feeding activity of consumers from their tributaries. Assessments of this kind may be relevant when deciding on the food availability for juvenile salmonids, inhabiting recipient waterbodies.