Wave transformations near a coronal magnetic null point

Context. Null points are often invoked in studies of quasi-periodic coronal jets and in connection with periodic signals preceding actual reconnection events. Although the periodicity of these events spans a wide range of periods, most show a 2- to 5-min periodicity compatible with the global p-modes. Aims We investigate whether magnetohydrodynamics (MHD) waves, in particular, acoustic p-modes, can cause strong current accumulation at the null points. This can in turn drive localized periodic heating in the solar corona. Methods. To do this, we began with a three-dimensional numerical setup incorporating a gravitationally stratified solar atmosphere and an axially symmetric magnetic field including a coronal magnetic null point. To excite waves, we employed wave drivers mimicking global p-modes. Using our recently developed wave-mode decomposition technique, we investigated the process of mode conversion, mode transmission, and wave reflection at various important layers of the solar atmosphere, such as the Alfvén acoustic equipartition layer and transition region. We examined the energy flux distribution in various MHD modes or in acoustic and magnetic components, as the waves propagate and interact with a magnetic field of null topology. We also examined current accumulation in the surroundings of the null point. Results. We found that most of the vertical velocity is transmitted through the Alfvén acoustic equipartition layer and maintains an acoustic nature, while a small fraction generates fast waves via the mode conversion process. The fast waves undergo almost total reflection in the transition region due to sharp gradients in density and Alfvén speed. There are only weak signatures of Alfvén wave generation near the transition region through the fast-to-Alfvén mode conversion. Because the slow waves propagate with the local sound speed, they are not much affected by the density gradients in the transition region and undergo secondary mode conversion and transmission at the Alfvén-acoustic equipartition layer surrounding the null point. This leads to fast-wave focusing at the null point. These fast waves have associated perturbations in current density and show oscillatory signatures that are compatible with the second harmonic of the driving frequency. This might result in resistive heating and in an enhanced intensity in the presence of finite resistivity. Conclusions. We conclude that MHD waves are a potential source for oscillatory current dissipation around the magnetic null point. We conjecture that in addition to oscillatory magnetic reconnection, global p-modes could lead to the formation of various quasi-periodic energetic events

Joint or not: unpacking the decision-making mechanism of pandemic control between two nations – from the perspective of cost optimization

Joint control has been proposed to alleviate the negative spillover of the pandemic. The authority faces a decision dilemma on whether to undertake joint control, which is overlooked by the scientific community. This paper, aiming to clarify the decision-making mechanism under cost optimization, draws on the optimization theory to find the optimal strategies and start time under independent and joint scenarios with an improved infectious disease model. Besides, a simulation analysis, based on the survey in Ruili – a border area between Myanmar and China, is employed. The crucial findings highlight that (1) The control measures contribute to reducing the peak number or peak time of confirmed patients under optimal decision. (2) As the delay of start time, the epidemic control for both countries undergoes from validity to failure. (3) More cost-savings come with earlier joint control but with uneven distribution. Joint strategy mitigates the cost for the one with severe epidemics, but the effect is insignificant for the other. This study, concentrating on cost optimization, provides a novel insight into pandemic control. The results enrich the decision analysis in the context of pandemic joint governance while providing inter-regional control support for the decision-maker to tackle various epidemics

Debiased population of very young asteroid families

Context. Asteroid families that are less than one million years old offer a unique possibility to investigate recent asteroid disruption events and test ideas about their dynamical evolution. Observations provided by powerful all-sky surveys have led to an enormous increase in the number of detected asteroids over the past decade. When the known populations are well characterized, they can be used to determine asteroid detection probabilities, including those in young families, as a function of their absolute magnitude. Aims. We use observations from the Catalina Sky Survey (CSS) to determine the bias-corrected population of small members in four young families down to sizes equivalent to several hundred meters. Methods. Using the most recent catalog of known asteroids, we identified members from four young families for which the population has grown appreciably over recent times. A large fraction of these bodies have also been detected by CSS. We used synthetic populations of asteroids, with their magnitude distribution controlled by a small number of parameters, as a template for the bias-corrected model of these families. Applying the known detection probability of the CSS observations, we could adjust these model parameters to match the observed (biased) populations in the young families. Results. In the case of three families, Datura, Adelaide, and Rampo, we find evidence that the magnitude distribution transitions from steep to shallow slopes near 300 to 400 meters. Conversely, the Hobson family population may be represented by a single power-law model. The Lucascavin family has a limited population; no new members have been discovered over the past two decades. We consider a model of parent body rotational fission with the escaping secondary tidally split into two components (thereby providing three members within this family). In support of this idea, we find that no other asteroid with absolute magnitude H ≤ 18.3 accompanies the known three members in the Lucascavin family. A similar result is found for the archetypal asteroid pair Rheinland–Kurpfalz

Object Detection for Self-Driving Car in Complex Traffic Scenarios

The application of convolutional neural networks (CNNs) in particular has greatly enhanced the object detection capabilities of self-driving cars, because of recent advancements in artificial intelligence (AI). However, striking a balance in vehicular settings between high precision and fast processing continues to be a persistent challenge. Developing nations such as India, possessing the second-largest global population, introduce unique intricacies to road scenarios. Numerous challenges arise on Indian roads, such as unique vehicle kinds and a variety of traffic patterns, such as auto-rickshaws, which are only seen in India. This study presents the outcomes of evaluating the YOLOv8 models, which have demonstrated superior performance in Indian traffic conditions when compared to other existing YOLO models. The examination utilized the dataset, compiled from data collected in the cities of Bangalore and Hyderabad, as well as their surrounding areas. The investigation's findings demonstrate how well the YOLOv8 models work to address the unique problems that Indian road conditions present. This study advances the development of autonomous vehicles designed for intricate traffic situations such as those found on Indian Roads

Hybrid solar and wind power generation with grid interconnection system

For India's modernization and urbanization, the need for energy is increasing extremely quickly. Because they are abundant in nature, renewable energy sources might be viewed as more advantageous than traditional ones. Both solar and wind energy are abundant and may be regarded as reliable sources of energy production. For the modernization of isolated areas and the electrification of rural areas, hybrid solar and wind energy systems can be deployed. This work does simulation of a hybrid solar and wind power system that is linked to the grid. For this study, a simulated model is utilized to determine the sag, swell, source voltage, source current. Solar-generated dc electricity is transformed into ac power using a universal converter. The benefit of using universal inverter is used to raise the system's overall power quality and get the Uninterruptible power supplies

Shark and ray monitoring on the marine critical habitat in Aceh Province

Aceh is the leading province in Indonesia, where the marine protection area for juvenile sharks and rays was first established, precisely in Aceh Jaya waters. Rigaih is the fishing port located closest to Aceh Jaya waters, where the angler fish closely with the marine protected area and even intersect with the juvenile’s habitat. This study aimed to examine shark and ray catches in Aceh Jaya before and after establishing the marine protection area. We conducted landing monitoring from 2017 to 2019 (before establishing a conservation area) and monitored in 2020 when the conservation area was established. We recorded that 73% of sharks and ray caught on set gill net. The composition of sharks and rays landed at PPI Rigaih consisted of Sphyrna lewini (75%, n=1783), Chiloscyllium punctatum (8%), Neotrygon caeruleopunctata (7%, n =175), and other species (10%). This study aimed to provide scientific recommendations to support shark conservation action in Aceh Jaya Waters. We found that Aceh Jaya waters are an important area for the life stages of several threatened species, including Scalloped Hammerhead Sharks (S.lewini) and Bottlenose Wedgefish (R.australiae) that are listed in Critically Endangered and listed in Appendix II CITES. Management to support the conservation action needs to be strengthened not only limited to Marine Protected Areas but also fisheries management to reduce the incidental catch of threatened sharks and ray species. Further studies need to be conducted to delineate the habitat range of threatened shark and ray species and identify fishing behaviours that pose a risk for incidental catches of sharks and rays

Integrated Renewable Energy-Based Wastewater Management System: A Sustainable Approach

The escalating global demand for water and the increasing need for sustainable wastewater treatment systems have spurred innovative approaches. This paper proposes an integrated renewable energy-based wastewater management system that harnesses solar and wind energy to power the treatment process. Renewable energy sources are aimed at reducing wastewater treatment's environmental impact while promoting energy efficiency. This study outlines the methodology, presents results, and discusses the implications of the proposed system

Micro/nanosized ferrite and hexaferrite by the polyol processes: The special case of structure and properties of SrFe

In this research, we have mainly focused on the controlled synthesis, and properties of micro/nanosized ferrite and hexaferrite powders by the polyol process. They are Fe3O4-type Sr-Fe-O oxide and SrFe12O19 with the structure and magnetic properties by SEM, XRD, and VSM measurements. After heat treatment, it was discovered that Sr element was gradually fully incorporated into Fe3O4 for the formation of the original hexaferrite structure of SrFe12O19 at 950°C

Framework to Identify Directions for Future Construction and Demolition Waste Management Technologies

Effective waste management is essential for sustainable urban development, and Construction and Demolition (C&D) waste poses a significant challenge due to its volume and composition in urban regions. In recent years, technological advancements have offered innovative solutions to improve the management of C&D waste. This exploratory study primarily uses secondary data and draws on case studies from 5 Indian cities and global literature on technological innovations in C&D waste management to propose a preliminary framework for identifying how different technologies can play a vital role and where they can be incorporated into the reverse supply chain of C&D waste in the Indian urban context. This paper paves the road for future research that will use this initial framework to identify more practical technological solutions based on a thorough understanding of ground reality, improving chances of technology adoption

Raspberry Pi-based home security monitoring system

The era of technology has opened space to facilitate daily tasks. Security cameras have nowadays become a necessity for every expert’s safety environment. A buzzer, PIR sensor, PI camera, and Raspberry Pi are used to create home security systems. The PIR sensor detects motion, the PI camera snaps an image, and the buzzer beeps. A notification will be delivered immediately to the owner’s Telegram account when the camera captures the person’s face and enables the posting of live video of that moment. It enables the user to record the incidents that happen at home. The purpose of developing the Telegram application is mainly to provide the owner with an Android application because nowadays society is more dependent on mobile technology. PIR sensors will be active when they detect people or animals, but they will deactivate when they detect breezes. As a result, the PI Camera will only record images of things like people and animals, not the wind. The PIR sensor, PI camera, and buzzer will all have a linear relationship to one another. When the PIR sensor is turned on, the PI camera and buzzer will also turn on, and vice versa