Local Configuration Research Articles

Blockchain-Based Peer-to-Peer Energy Trading System Using Open-Source Angular Framework and Hypertext Transfer Protocol

Renewable energy resources have been gaining ground in recent years and we are on the verge of a decentralized energy market with consumers becoming prosumers. Platforms that facilitate peer-to-peer (P2P) sale or purchase of energy are therefore essential. This paper presents a way to trade energy across P2P networks using blockchain technology. The main server is a Raspberry Pi 4 Model B (Pi4B), on which the user interface (UI) as well as the private Ethereum blockchain are configured. The blockchain also implements a smart contract. For the purpose of developing the UI that provides assistance in conducting trading activities, an open-source Angular framework is used. Also explored in the study is the development of an Internet of Things (IoT) server using the latest ESP32-S3 microcontroller. The field instrumentation devices (FIDs) are connected to the microcontroller for the purpose of data acquisition and for subsequent transmission to an IoT server. The blockchain network maintains a record of all transactions in an immutable manner. Assuring security is achieved through a local configuration of the system, hosted on a private network with restricted access. For the purposes of information security and data integrity, additional security measures are also considered, such as a secret recovery phrase, firewalls, login credentials and private key. Among the servers and clients, there is an implementation of a Hypertext Transfer Protocol. The P2P energy trading approach involving renewable energy designed for remote communities is explained and illustrated in this paper.

Giant comprehensive capacitive energy storage in lead-free quasi-linear relaxor ferroelectrics via local heterogeneous polarization configuration

The local heterogeneous polarization configuration in quasi-linear RFEs delivers a large Wrec (∼7.01 J cm−3), concurrent with an ultrahigh η (∼94.3%), demonstrating giant comprehensive energy storage for cutting-edge capacitors applications.

Impact of hydrophobicity on local solvation structures and its connection with the global solubilization thermodynamics of amphiphilic molecules.

The relationship between the local solvation structures and global thermodynamics, specifically in the case of amphiphilic molecules, is a complex phenomenon and is not yet fully understood. With the prior knowledge that local solvation structures can impose a significant impact on the overall solvation process, we here combine THz spectroscopic analysis with MD simulations to investigate the impact of the altered hydrophobicity and polarity of amphiphilic solute molecules on the local solvation configurations. We use two water soluble alcohols: ethanol (EtOH) and its fluorinated counterpart, 2,2,2-trifluoroethanol (TFE), as model solutes. Our study is aimed to determine the relative abundance of different hydrogen bonded conformers and to establish a correlation between the spectral signatures (as obtained from THz spectroscopic measurements) and microscopic solute-solvent interactions associated with the local solvation structures (as obtained from MD simulations). Finally, we estimate the possible energetic parameters associated with the alcohol solubilization process. We found that while both the alcohols are completely water soluble, they receive a contrasting solvation energy share in terms of entropy and enthalpy. We understand that these findings are not limited to the specific system studied here but can be broadly extrapolated to other amphiphilic aqueous solutions.

Decentralized Federated Reinforcement Learning for User-Centric Dynamic TFDD Control

The explosive growth of dynamic and heterogeneous data traffic brings great challenges for 5G and beyond mobile networks. To enhance the network capacity and reliability, we propose a learning-based dynamic time-frequency division duplexing (D-TFDD) scheme that adaptively allocates the uplink and downlink time-frequency resources of base stations (BSs) to meet the asymmetric and heterogeneous traffic demands while alleviating the inter-cell interference. We formulate the problem as a decentralized partially observable Markov decision process (Dec-POMDP) that maximizes the long-term expected sum rate under the users' packet dropping ratio constraints. In order to jointly optimize the global resources in a decentralized manner, we propose a federated reinforcement learning (RL) algorithm named federated Wolpertinger deep deterministic policy gradient (FWDDPG) algorithm. The BSs decide their local time-frequency configurations through RL algorithms and achieve global training via exchanging local RL models with their neighbors under a decentralized federated learning framework. Specifically, to deal with the large-scale discrete action space of each BS, we adopt a DDPG-based algorithm to generate actions in a continuous space, and then utilize Wolpertinger policy to reduce the mapping errors from continuous action space back to discrete action space. Simulation results demonstrate the superiority of our proposed algorithm to benchmark algorithms with respect to system sum rate.

Towards the next generation intelligent transportation system: A vehicle detection and counting framework for undisciplined traffic conditions

Modern development in deep learning and computer vision techniques, intelligent transportation system (ITS) has emerged as a useful tool for building a traffic infrastructure in smart cities. Previously, several computer vision techniques have been proposed for vehicle recognition, which were limited in handling undisciplined, dense and laneless traffic conditions. Moreover, these frameworks did not incorporate many of the local vehicle configurations common in South Asian countries such as Pakistan, Bangladesh, and India. Considering the limitations of previous frameworks, this paper presents efficient vehicle detection and counting model for undisciplined conditions including dense and laneless traffic, occulusion cases and diverse range of local vehicles. A dataset of more than 2400 images of vehicles has been collected comprising of six new categories of local vehicles, and considering undisciplined traffic conditions to ensure robustness in vehicle detection and counting system. Transfer learning based technique has been used, using faster R-CNN model with Inception V2 as underlying architecture. The experimental results show a precision of 86.14% in terms of mAP. The work finds its application in South Asian contexts as more smart cities are formed in this region. The proposed framework will enable traffic monitoring with higher reliability, accuracy and granularity, contributing in having next-generation ITS.

Charge delocalization and aromaticity of doubly reduced double-walled carbon nanohoops.

Cycloparaphenylenes (CPPs) exhibit selective host capabilities, featuring the ability to incorporate smaller CPPs to form double-walled host-guest complexes. Moreover, CPPs can also be stabilized by global aromaticity under twofold oxidation or reduction, involving electronic conjugation along with the overall structural backbone. Herein we explore the structural modifications, bonding, electron delocalization and magnetic properties of doubly reduced double-walled CPP complexes with DFT methods, in the isolated and aggregate [n + 5]CPP⊃[n]CPP2- (n = 5-8) species. Our results show that the hosts undergo structural, bonding and delocalization deformations towards quinoidal configurations and exhibit global long-ranged shielding cones similar to global aromatic free dianionic CPPs, accounting for charge delocalization on the outer nanohoops, whereas the guests preserve local aromatic benzenoid configurations, resulting in global and local aromatic circuits within the host-guest aggregate. This observation suggests that in multi-layered related species electronic delocalization will be retained at the outer structural surface. The aromaticity of the hosts is manifested in the strong upfield shifts of the guests 1H-NMR signals. Hence, CPP complexes can be extended to doubly reduced species stabilized by global host aromaticity expanding our understanding of doubled-walled nanotubes at the nanoscale regime.

Modulating local electronic structure enhances superior electrochemical activity in Li-rich oxide cathodes

The electrochemical activity and stability of Li2MnO3are affected synchronously by lattice vacancies and local coordination configuration.

Heredity of clusters in liquid Ta rapid solidification process and its correlation with local symmetry

Metallic glass (MG) has received intensive attention in the fields of amorphous physics and materials science, owing to its excellent mechanical properties, good corrosion resistance, and large elastic deformation limit. Comparing with traditional oxide glass, the limited glass-forming ability (GFA) seriously restricts the application of MG in engineering. Therefore, the GFA has been a hot scientific issue in the field of amorphous material research. Recently, scientists have fully realized that GFA is closely related to the local atomic structure in liquid as well as its evolution features. Since the MG is called the “freezing” liquid, exploring the correlation of local atomic structures between liquid phase and solid phase under rapid solidification conditions is helpful in understanding the microstructural mechanism of GFA. Therefore, the rapid solidification process of liquid Ta is investigated via molecular dynamics simulation. The pair correlation function (PDF), the largest standard cluster (LSC), and the reverse atomic trajectory tracking methods are used to characterize and analyze the microstructure and its evolution during the rapid solicitation of liquid Ta. The results show that the local atomic configurations of the rapidly solidified Ta are various Kasper clusters as well as their distorted configurations, among of which [1/444, 10/555, 2/666] deformed icosahedron (or Z13 cluster) accounts for the highest proportion. The trend of hereditary ability of clusters revealed by the onset temperature of continuous heredity is consistent well with that by the fraction of staged heredity. The geometric symmetry of clusters can be quantitatively characterized by using the local symmetry parameter (LSP). The hereditary ability of clusters is closely related to their LSP. The local five-fold symmetry is beneficial to enhancing hereditary ability, while local four- and six-fold symmetry are disadvantageous for that. The probability of clusters with the same LSC index emerging in the energy range follows the Gaussian distribution, and the expected average atomic potential energy <inline-formula><tex-math id="M3">\begin{document}$ {E}_{\rm exp}^{j} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20231153_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20231153_M3.png"/></alternatives></inline-formula> is almost linearly related to the LSP, and <inline-formula><tex-math id="M4">\begin{document}$ {E}_{\rm exp}^{j} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20231153_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="24-20231153_M4.png"/></alternatives></inline-formula> decreases with the increase of LSP<sub>5</sub>. The high local five-fold symmetry reduces the average atomic potential energy of LSC, thereby enhancing its configurational heredity. These findings have guiding significance in improving GFA through regulating the local symmetry of liquid monatomic metals or alloys.

Excitation localization/delocalization induced intramolecular singlet fission in cyclopentadithiophene-based quinoidal derivatives.

Two triplet excitons are generated through an ultrafast photophysical process, namely singlet fission (SF), providing a solution for efficient solar energy usage. In this work, we provide an effective guideline for designing SF materials by adjusting the planarity in cyclopentadithiophene (CPDT) derivatives. A practical strategy is proposed for tuning the quinoidal-biradical resonance structures by varying the electron push-pull groups of CPDTs for SF. The localized, delocalized, and intermediate charge-transfer excited configurations are predicted in the singlet excited state via computational simulations, which is further confirmed by ultrafast spectroscopy. Deduced from the potential energy surfaces in the low-lying excited states and transient absorption, the delocalized excited state is formed in 2.1 ps via postulated intramolecular SF in a polar solvent, followed by the ultrafast formation of the free triplet state with a lifetime of 6.8 ps. In comparison with different cross-conjugated chromophores, it is found that the increase in the charge separation could enhance the triplet-pair generation for iSF. We expect that by introducing symmetry-breaking modifications in the electronic configurations and adjusting the separation between the push-pull groups of CPDTs, it should be possible to prolong the duration of the free triplet state by preventing recombination within the triplet-pair excited configuration.

THE EFFECTS OF PARTICLE SIZE AND TEMPERATURE ON THE STABILITY AND LOCAL STRUCTURAL EVOLUTIONS OF AMORPHOUS BULK AND NANOPARTICLES OF THE FeNI3 ALLOYS

The effects of particle size (2-6 nm) and temperature (300-1900 K) on the stability and local structural evolutions of amorphous bulk and nanoparticles of the FeNi3 alloys have been studied by using classical molecular dynamics (MD) simulation method combined with embedded atom model (EAM) in Largescale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The nanoparticles were obtained from the unstable amorphous bulk FeNi3 alloys. MD simulations have been performed for glassy FeNi3 intermetallic alloy by making use of pairwise interatomic interaction potentials and electron densities calculated via EAM method. The formation and evolution of structures and their stability have been analyzed at a wide temperature range (300-1900 K) by calculating radial distribution functions (RDF), interatomic distances (ID), coordination numbers (CN), core-to-surface concentration profiles, as well as Voronoi analysis. According to the results, although some deviations in the structural properties occurred during the heat treatment, the amorphous nanoparticles exhibited the same crystal structure and local atomic configuration with its bulk counterpart at room temperature.

Fast Verification of Network Configuration Updates

With the expansion of network services, large-scale networks have progressively become common. The network status changes rapidly in response to customer needs and configuration changes, so network configuration changes are also very frequent. However, no matter what changes, the network must ensure the correct conditions, such as isolating tenants from each other or guaranteeing essential services. Once changes occur, it is necessary to verify the after-changed network. Whereas, for the verification of large-scale network configuration changes, many current verifiers show poor efficiency. In order to solve the problem of multiple global verifications caused by frequent updates of local configurations in large networks, we present a fast configuration updates verification tool, FastCUV, for distributed control planes. FastCUV aims to enhance the efficiency of distributed control plane verification for medium and large networks while ensuring correctness. This paper presents a method to determine the network range affected by the configuration change. We present a flow model and graph structure to facilitate the design of verification algorithms and speed up verification. Our scheme verifies the network area affected by obtaining the change of the Forwarding Information Base (FIB) before and after. FastCUV supports rich network attributes, meanwhile, has high efficiency and correctness performance. After experimental verification and result analysis, our method outperforms the state-of-the-art method to a certain extent.

Air/water interfacial waves with a droplet at the tip of their crest

In nature, it is common to observe water wave crests with a droplet at their tip. This fascinating configuration remains unexplained from the physical point of view. The present study explores such a unique local configuration numerically. Solitary waves that propagate at the interface between two layers of irrotational fluids are considered. Extending the work of Guan et al. [“A local model for the limiting configuration of interfacial solitary waves,” J. Fluid Mech. 921, A9 (2021)], the density ratio has been decreased to a very small value equal to 0.001, which is close to the air/water density ratio at sea level (0.0013). A highly accurate solution for the limiting configuration of solitary waves is obtained by solving the irrotational Euler equations using the boundary integral method and Newton's iterations. It is confirmed that the limiting configuration consisting of a droplet sitting on a crest with a 120° angle exists for very small density ratios. This limiting configuration obviously does not exist for surface waves with a void on the top, thus stressing the crucial role played by the air. The droplet is stationary in a frame of reference moving with the wave and experiences intense shear at its tip. From the energy point of view, the formation of a crest with a droplet is accompanied by a remarkable drop of kinetic and potential energies of water in the vicinity of the crest. Furthermore, we present a simple set of scaling relations for the fall of the droplet.

Спектры люминесценции и необычный температурный сдвиг бесфононной эмиссионной линии V-=SUP=-3+-=/SUP=- в SrTiO-=SUB=-3-=/SUB=-

The paper presents the first observation of photoluminescence spectra of V3+ impurity in SrTiO3. The broad band of the observed emission is located in the near IR region and at low temperatures consists of a pronounced zero-phonon line (ZPL) with a maximum at 1157.1 nm (8642 сm-1) at 77 K and developed vibronic sidebands extending to 1450 nm. The observed ZPL is associated with an intracenter 1T2g → 3T1g or a closely located 1Eg → 3T1g emission transition in V3+ (3d2) ions replacing Ti4+ ions. It was found that the temperature shift of zero-phonon line is unusually large and its frequency decreases upon lowering the temperature. The local configuration instability of V3+ ions in the 3T1g ground state caused by soft TO1 temperature-dependent phonon mode present in SrTiO3 is considered as a possible source of the observed unusual temperature shift.

(Up) Against the Prefecture: Associations and Activists in the Cause of Foreign Nationals at Odds with the State

Based on fieldwork carried out in northern France, this article looks at associations and activists—both volunteers and paid employees—working for the cause of foreign nationals, and seeks to understand their role in the reception and defence of these populations through the figure of the “intermediary”. By analysing local configurations of intermediation and delegation, the article shows that associations and activists constitute intermediary figures between foreign nationals, the state and migration policies. The methods used by activists contribute to the transmission of knowledge, skills, categories and norms on and about immigration: activists appear to be both legal experts and links in the chain of migration policies. In turn, the position of intermediary says something about activists, the dilemmas they face and the demarcation strategies they sometimes employ.

Quantifying chemical fluctuations around medium-range orders and its impact on dislocation interactions in equiatomic CrCoNi medium entropy alloy

Equiatomic multi-principal element alloys manifest unique mechanical properties derived from the single-phase solid solutions with compositional disorders. Recently discovered medium-range orders (MROs) with a size of 1–5 nm in CrCoNi medium entropy alloy acclaimed measurable impact on mechanical properties, which, however has been questioned by density functional theory calculations. Here we report that the formation of MROs is accompanied by the redistribution of constituent elements, and the subtle chemical composition fluctuations could by directly probed and quantified by using a state-of-the-art aberration-corrected transmission electron microscope. The presence of such MROs contributes to an appreciable increase in yield strength (∼40 MPa) with a higher work hardening rate, originating from the strong dislocation interactions with MROs at the incipient plastic deformation. These findings demonstrate that MROs have a significant impact on reducing the mean free path of full/partial dislocations along a specific slipping plane, offering a new avenue for strengthening of equiatomic element alloys by tuning local composition and atomic configurations.

Multipartite entanglement and purity dynamics in channels influenced by fractional Gaussian noise

The dynamical map of entanglement, coherence and mixedness in four-qubit maximally entangled GHZ-class state paired with classical channels driven by fractional Gaussian noise is investigated. The qubit-channel coupling is assumed in four distinct ways: common, bipartite, tripartite, and independent local channel-qubit configurations comprising single, double, triple, or independent noisy sources. Using entanglement witness, negativity, purity and von Neumann entropy, except for the independent configuration, we show that indefinite entanglement, coherence, and purity preservation may be simulated in multipartite GHZ-like states. Quantum correlations and purity decrease exponentially in four qubits, and exact fluctuating local field behavior, as well as entanglement sudden death and birth revivals, are completely suppressed. Entanglement, coherence, and purity preservation are affected by noise and the number of independent channels utilized. The Hurst parameter of fractional Gaussian noise was discovered in the four qubits to improve entanglement, coherence and avoid mixedness.

Sound transmission loss of meta-acoustic barriers with anomalous effective-mass

Meta-acoustic barriers (MABs) that are inspired by acoustic metamaterials (AM) offer opportunities to defy mass law-driven sound transmission loss (TL) performance that is characteristic of conventional acoustic barriers. In this analytical parametric study, the TL behavior of MABs that incorporate various local oscillator configurations are analyzed using an effective-mass modeling approach. Resonant, damped and inertant local oscillator configurations and combinations thereof that result in negative and complex effective-mass for the meta-acoustic barrier are considered. The influence of the local configuration’s orientation, oblique incidence and the presence of multiple oscillator types are examined using nondimensionalized metrics and compared to the performance of static mass and volume-equivalent limp mass and double wall barriers. It is shown that due to their anomalous effective-mass, such barriers display tunable TL bandwidths exceeding that of mass-equivalent conventional barriers indicating new device implications. The effective-mass modeling approach can easily be adapted to account for the presence of different dynamic features within various types of inclusions considered and is thus an efficient tool to evaluate meta-acoustic barrier designs. Inasmuch as these meta-acoustic barrier structures can be realized using recent advances in additive and hybrid manufacturing techniques, opportunities exist to create lightweight barriers for tonal and broadband acoustic applications.

A comprehensive assessment of leachate contamination at a non-operational open dumpsite: mycoflora screening, metal soil pollution indices, and ecotoxicological risks.

The final disposal of municipal solid waste (MSW) in dumpsites is still a reality worldwide, especially in low- and middle-income countries, leading to leachate-contaminated zones. Therefore, the aim of this study was to carry out soil and leachate physicochemical, microbiological, and toxicological characterizations from a non-operational dumpsite. The L-01 pond samples presented the highest physicochemical parameters, especially chloride (Cl; 4101 ± 44.8mg L-1), electrical conductivity (EC; 10,452 ± 0.1 mS cm-1), and chemical oxygen demand (COD; 760 ± 6.6mg L-1) indicating the presence of leachate, explained by its close proximity to the landfill cell. Pond L-03 presented higher parameters compared to pond L-02, except for N-ammoniacal and phosphorus levels, explained by the local geological configuration, configured as a slope from the landfill cell towards L-03. Seven filamentous and/or yeast fungi genera were identified, including the opportunistic pathogenic fungi Candida krusei (4CFU) in an outcrop sample. Regarding soil samples, Br, Se, and I were present at high concentrations leading to high soil contamination (CF ≤ 6). Pond L-02 presented the highest CF for Br (18.14 ± 18.41mgkg-1) and I (10.63 ± 3.66mgkg-1), while pond L-03 presented the highest CF for Se (7.60 ± 1.33mgkg-1). The most severe lethal effect for Artemia salina was observed for L-03 samples (LC50: 79.91%), while only samples from L-01 were toxic to Danio rerio (LC50: 32.99%). The highest lethality for Eisenia andrei was observed for L-02 samples (LC50: 50.30%). The applied risk characterization indicates high risk of all proposed scenarios for both aquatic (RQ 375-909) and terrestrial environments (RQ > 1.4 × 105). These findings indicate that the investigated dumpsite is contaminated by both leachate and metals, high risks to living organisms and adjacent water resources, also potentially affecting human health.

A machine-learned spin-lattice potential for dynamic simulations of defective magnetic iron

A machine-learned spin-lattice interatomic potential (MSLP) for magnetic iron is developed and applied to mesoscopic scale defects. It is achieved by augmenting a spin-lattice Hamiltonian with a neural network term trained to descriptors representing a mix of local atomic configuration and magnetic environments. It reproduces the cohesive energy of BCC and FCC phases with various magnetic states. It predicts the formation energy and complex magnetic structure of point defects in quantitative agreement with density functional theory (DFT) including the reversal and quenching of magnetic moments near the core of defects. The Curie temperature is calculated through spin-lattice dynamics showing good computational stability at high temperature. The potential is applied to study magnetic fluctuations near sizable dislocation loops. The MSLP transcends current treatments using DFT and molecular dynamics, and surpasses other spin-lattice potentials that only treat near-perfect crystal cases.

Overlooked role associated with the active-site density in perovskite nickelates to the anisotropic catalytic activities for water splitting

The d-band correlated rare-earth nickelate (ReNiO3) is a typical quantum material that exhibits comparable reactivities to the noble metal oxide in oxygen evolution reactions (OER) for water splitting, apart from their well-known correlated electronic functionalities, such as metal to insulator transition. Nevertheless, the potential anisotropy in the catalyst reactivity of OER for ReNiO3 and its underneath mechanisms are yet under debate. Herein, we demonstrate the previously overlooked role associated with the surface atomic density of the Ni active-site that dominant in the anisotropic OER catalytic activities of ReNiO3. Despite its more localized electron configurations as indicated by the near edge x-ray absorption fine structure analysis and correlated transport, the OER catalytic activity was surprisingly observed to be higher for quasi-single crystalline NdNiO3 (001)/LaAlO3 (110), compared to that of NdNiO3(010)/LaAlO3 (001) and NdNiO3(1¯10)/LaAlO3 (111). This is attributed to the highest surface atomic density associated with the Ni active-site within NdNiO3 (001), compared to NdNiO3 (010) and NdNiO3 (1¯10), and this kinetically reduces the overpotential of OER and the charge transfer resistance of NdNiO3 (001). The anisotropic OER activity sheds a light on the crystal orientation in the optimization of the ReNiO3 catalyst for water splitting.