Merging Process Research Articles

Reticular chemistry for the rational design of mechanically robust mesoporous merged-net metal-organic frameworks

Reticular chemistry for the rational design of mechanically robust mesoporous merged-net metal-organic frameworks

Contrasting Mesoscale Convective System Features of Two Successive Warm-Sector Rainfall Episodes in Southeastern China: A Satellite Perspective

Based on Himawari-8 satellite observations, the mesoscale convective system (MCS) behaviors of two successive but distinct warm-sector rainfall episodes (EP1 and EP2) on 6–7 May 2018 over southeastern China were compared, with the latter episode being a record-breaking rainfall event. Results showed that MCSs played a dominant role in EP2, but not in EP1, by contributing over 80% of the extreme rainfall total and all the 10-min rainfalls over 20 mm. MCS occurrences were more frequent in EP2 than EP1, especially in the coastal rainfall hotspots, along with more frequent merging processes. Overall, the MCS samples in EP2 were larger in size, more intense, and moved slower and more in parallel to their orientation, which facilitated local rainfall accumulation. Two new indices are proposed—the overlap index (OLI) and merging potential index (MPI)—to evaluate two MCS processes vital for rainfall production: the repeated passage of an individual MCS over given areas and the merging between MCSs, respectively. Both OLI and MPI in EP2 were significantly larger than in EP1, which tended to produce larger maximum rainfall amount and stronger 10-min rain rates in the following hour. These results demonstrate the potential value of satellite-based MCS information for heavy rainfall nowcasting, which is particularly significant for warm-sector rainfall with its limited predictability.

The SCUBA-2 Cosmology Legacy Survey: the EGS deep field – III. The evolution of faint submillimetre galaxies atz< 4

ABSTRACTWe present a demographic analysis of the physical and morphological properties of $450/850~\mu \rm m$-selected galaxies from the deep observations of the SCUBA-2 Cosmology Legacy Survey in the Extended Groth Strip that are detected below the classical submillimetre-galaxy regime ($S_{850\, \mu \rm m}\lesssim 6~\rm mJy$ beam−1) and compare them with a sample of optically selected star-forming galaxies detected in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey in the same field. We derive the evolution of the main sequence of star-forming galaxies, finding a steeper specific star formation rate versus stellar mass at z > 2.5 than previous studies. Most faint submillimetre-galaxies fall within 3σ of the main sequence, but 40 per cent are classified as starbursts. Faint submillimetre galaxies have 50 per cent larger sizes at 2 < z < 3 than optically selected star-forming galaxies of the same mass range. This is also the redshift bin where we find the largest fraction of starbursts, and hence we could be witnessing merging processes, as confirmed by the preference for visual-morphology classifications of these systems as irregular disc galaxies and mergers. Both populations show an increment towards lower redshifts (z < 2) of their concentration in H-band morphology, but faint submillimetre galaxies on average show larger concentration values at later times. These findings support the claim that faint submillimetre galaxies are mostly a population of massive dust-obscured disc-like galaxies that develop larger bulge components at later epochs. While the similarities are great, the median sizes, starburst numbers, and H-band concentration of faint submillimetre galaxies differ from those of optically selected star-forming galaxies of the same stellar mass.

Spectroscopic observation of super-Alfvénic field-reversed configuration merging process by mixing of tracer ions.

Visualization of the collisional merging formation process of field-reversed configuration (FRC) has been attempted. In the collisional merging formation process, two initial FRC-like plasmoids are accelerated toward each other by a magnetic pressure gradient. The relative speed of the collision reaches several times the typical ion sonic speed and Alfvénic speed. The magnetic structure of the initial-FRCs is disrupted in the collision process, but the FRC-like magnetic structure is reformed in ∼30 µs after the collision. Magnetic reconnection should occur in this process; however, general theoretical models in magnetohydrodynamics approximation cannot be applied to this process because of the high-beta nature of FRC and super-Alfvénic/sonic relative speed. In this work, the spectroscopic observation of the collisional merging FRC formation was conducted to evaluate the timescale and geometry of merging. A slight amount of tracer element (e.g., helium) was mixed into one of two initial-FRCs. Mixing of the tracer did not cause serious adverse effects on the performance of the initial-FRC in the collision and merging processes. The collision and merging processes were visualized successfully and observed using a fast-framing camera with a bandpass filter. The timescale of merging and the outflow speed in the collisional merging process of FRCs were optically evaluated for the first time.

Numerical investigation of micro-droplets mixing in electrowetting-on-dielectric digital microfluidics: The merging process and frequency response

In this study, we numerically investigate the mixing of two sessile micro-droplets in open electrowetting-on-dielectric (EWOD) digital microfluidics. The mixing process is composed of the merging and the subsequent oscillation process achieved by applying alternating voltage (AC voltage) to the droplet with desired frequency and amplitude. The numerical results show excellent agreement with previous numerical and experimental studies. The focus of this study is probing into the effects of the merging process on the subsequent AC voltage-actuated oscillation of the droplet. It is observed that the merging process breaks the azimuthal symmetry of the droplet and, hence, introduces the sectoral mode to the subsequent AC voltage-actuated oscillation. The frequency dependence of the enhancement and dissipation of the sectoral oscillation is quantitatively investigated. Furthermore, the sectoral oscillation inherited from the merging process is confirmed to have little impact on the zonal oscillation of the droplet. The oscillation-based mixing enhancement of the droplet is numerically verified.

Revealing Double White Dwarf Mergers with Multi-messenger Signals

A significant number of double white dwarfs (DWDs) are believed to merge within the Hubble time due to the gravitational wave (GW) emission during their inspiraling phase. The outcome of a DWD system is either a type Ia Supernova as the double-degenerate model, or a massive, long-lasting merger remnant. Expected multi-messenger signals of these events will help us to distinguish detailed merging physical processes. In this work, we aim to provide a generic scenario of DWD merging, investigate the emission of all major messengers, with a focus on GWs and neutrinos. Our goal is to provide some guidance for current and future (collaborative) efforts of multi-messenger observations. Throughout the merging evolution of a DWD system, different messengers (GW, neutrino and electromagnetic wave) will dominate at different times. In this work, we show that DWD merger events located at the distance of 1 kpc can indeed produce detectable signals of GWs and neutrinos. The GW frequency is in 0.3–0.6 Hz band around 10 days before tidal disruption begins. We estimate that in optimistic situations, the neutrino number detected by upcoming detectors such as JUNO and Hyper-Kamiokande can reach O(1) for a DWD merging event at ∼1 kpc.

Development of visible light tomographic imaging system for field-reversed configuration collisional merging experiment.

A visible light tomographic imaging system has been developed for the collisional merging experiment of field-reversed configurations (FRCs) on the FRC Amplification via Translation-Collisional Merging device at Nihon University. Two FRCs formed by field-reversed theta-pinch translate at super-Alfvénic velocity and collide with each other. The translation and collision processes are completed in 20-30 µs, and a single FRC is reformed in ∼70 µs. To study these translation and collisional merging processes, the tomographic system, including fast response tomographic cameras and a reconstruction method assuming a Rigid-Rotor (RR) model, is developed. The developed tomographic cameras simply consist of 16 channels of multi-anode photomultipliers, a band-pass filter, a slit, and a cylindrical lens, which expands the viewing angle. Because the viewing angle is limited by the size of the viewports of the metal chamber, the iterative method assuming the RR model has been applied to reconstruct tomographic images from a small number of projections. The developed tomographic imaging system can estimate the behavior of FRCs. Four cameras are installed in the two cross sections near the collision point. The radial shift of each translated FRC can be calculated by this system. Details of the developed tomographic camera system and RR reconstruction method are reported.

Development of Rogowski probe for internal plasma current measurement in the collisional merging process of field-reversed configurations.

To directly detect the spatial distribution of a plasma current during the collisional merging of two field-reversed configurations (FRCs) in the FAT-CM (FRC Amplification via Translation-Collisional Merging) device, an internal current probe using Rogowski coils has been developed. An FRC is a type of magnetically confined plasma maintained by a diamagnetic plasma current flowing in the toroidal direction. Self-organized FRC formation and increased poloidal flux have been observed following the destructive perturbation during the collision in collisional merging FRC formation when two initial-plasmoids collide at a relative speed of 300-400 km/s to form one FRC. It is indicated that the toroidal plasma current is driven in those processes. In this research, an internal Rogowski probe was designed and developed to have a high-frequency response to capture a rapid change of the plasma current in a few microseconds during the collision/merging process. The FRC plasma in FAT-CM has relatively high temperature (∼100 to 200eV) and high density (∼1020 to 1021m-3). As a result, the probe was built to be as compact as possible to minimize disruption to the plasma. Because of its high melting point and low Z property, a machinable boron nitride ceramic was chosen to shield the Rogowski coils thermally and electrically from the plasma. All connections and seams were constructed such that the epoxy glue used for the probe assembly was not exposed to the plasma.

Precipitation evolution induced by electron beam irradiation in Mg-RE alloys

At present, it is of important significance for the microstructure design of rare earth magnesium (Mg-RE) alloys to comprehend the evolutionary mechanisms of metastable precipitation phases. In this study, a phase transition from β S ′ to β 1 caused by electron beam irradiation is studied particularly in a Mg-Y-Ce alloy by means of atomic scale scanning transmission electron microscopy. Results show that the structural evolution from β S ′ to β 1 precipitates can be accomplished thoroughly within two minutes for a nanosized particle. It is mainly ascribed to the fact that the increasing heat and vacancy concentration generated by electron beam irradiation can greatly accelerate the atomic diffusion, especially along c -axis direction. It is confirmed that the phase transition from β S ′ to β 1 is segmented into the two stages, including the preceding diffusive and the subsequent displacive phase transitions. The findings will provide some useful clues to control effectively the morphologies of precipitates and the precipitation behaviors of Mg-RE alloys. By means of electron beam irradiation, a phase transformation from β S ′ to β 1 in a Mg-Y-Ce alloy is studied by atomic scale scanning transmission electron microscopy. It is found that the evolution is accomplished thoroughly within two minutes. The whole process involves not only diffusive but also displacive phase transformations. • The β 1 precipitate is derived from the merging of β S ′ in Mg-Y-Ce alloy. • Electron beam irradiation can accelerate the merging process of β S ′. • The transition involves both diffusive and displacive phase transformations.

MERGE and Pair-Merge of Heads

Jae-Young Shim. 2022. MERGE and Pair-Merge of Heads. Studies in Modern Grammar 115, 1-26. Chomsky (2019a,b, 2020) reformulates the standardly assumed conception of Merge in terms of workspace, arguing that the operation only operates over syntactic objects placed in a workspace. Alongside this revised version of Merge, often referred to as ‘(capital) MERGE’ in the literature, he proposes a principle of Resource Restriction which, he claims, MERGE ought to meet. In this paper, I first review the workspace-based operation MERGE and present its empirical and conceptual advantages over its predecessor, Merge.
 I then examine the two proposals on pair-Merge of heads put forward in Chomsky (2015) and Epstein, Kitahara and Seely (2016) with discussions on their potential conceptual problems with respect to rule ordering and Anti-Locality. I further show that possible implementations of pair-Merge of heads in the MERGE-based system give rise to some new problems in terms of accessibility defined by Minimal Search. Finally, focusing on pair-MERGE of R and v*, I present an alternative analysis to resolve the addressed problems, arguing that the pair-merged structure of R and v* is generated, not in the course of derivation but inside the Lexicon via a merging process I call Lexical Merger, or l-merger.

Fuzzy Superpixel-based Image Segmentation

This article presents a multi-phase image segmentation methodology based on fuzzy superpixel decomposition, aggregation and merging. First, a collection of layers of dense fuzzy superpixels is generated by the variational fuzzy decomposition algorithm. Then a layer of refined superpixels is extracted by aggregating various layers of dense fuzzy superpixels using the hierarchical normalized cuts. Finally, the refined superpixels are projected into the low dimensional feature spaces by the multidimensional scaling and the segmentation result is obtained via the mean-shift-based merging approach with the spatial bandwidth adjustment strategy. Our algorithm utilizes the superimposition of fuzzy superpixels to impose more accurate spatial constraints on the final segmentation through the fuzzy superpixel aggregation. The fuzziness of superpixels also provides spatial features to measure affinities between fuzzy superpixels and refined superpixels, and guide the merging process. Comparative experiments with the existing approaches reveal a superior performance of the proposed method.

Combined Safety and Coordination of Connected Automated Vehicles in Merging Area with Featuring Optimal Merging Positions

Freeway on-ramp merging area is deemed to be typical bottlenecks section, which leads to low traffic efficiency, congestions, and frequent accidents. Most existing studies on merging for the connected and automated vehicles focus on merging at a single fixed merging point. However, the problem of coordination between merging vehicle and arterial traffic flow in the acceleration lane is ignored in the existing studies. This study proposes a merging model, which combined safety and coordination of CAVs with featuring optimal merging positions. The proposed model has two stages: one is analysis of merging velocity of the insertable gap and the other one is determining constraint condition of cooperative merging. The outputs of first stage are interval of merging speed and the mergeable range. The outputs of second stage are optional insertable gap and the corresponding driving scheme. Then, a traffic simulation experiment is designed to evaluate the proposed model. The simulation results show that the proposed model can effectively guarantee driving safety and make the merging process smoother with 28.7% reduction in travel time for the CAV merging. Furthermore, the proposed model does not sacrifice the interests of surrounding traffic to assist in CAV merging. The results indicate the promising potential of using the proposed methods can approximately get a fair use of road resources for each CAV.

Cooperative social network community partition: A data envelopment analysis approach

Community partition is a significant task in social network analysis. For some interest networks, the interest of nodes may influence the formation of community. Considering the cooperation relation among nodes, we propose a cooperative social network partition approach by using the technique of data envelopment analysis. In this approach, the interest relationship among decision making units (DMUs) is identified by measuring the increased revenue of two cooperative DMUs, and then, a weighted interest network is constructed correspondingly. In this interest network, each node would like to cooperate with others to gain more benefits. Regarding each node as a player, the formation of community can be achieved by a cooperative game. We employ Shapley value mechanism mainly including five algorithms, i.e., maximum Shapley value of each node, expand algorithm, check stability, update, and merge process, to achieve community partition. Finally, the proposed method is applied to mineral resource of 31 provinces in Chinese mainland.

Lattice Boltzmann simulation of wetting gradient accelerating droplets merging and shedding on a circumferential surface

A lattice Boltzmann method (LBM) based on Shan-Chen pseudo-potential model is used to investigate the process of droplets merging and shedding on a gradient wetting circular surface. The effects of wetting gradient, radius, and radius ratio on droplet merging and shedding were mainly explored. The results show that applying a wetting gradient on the circumferential surface can accelerate the process of droplet merging and shedding. The velocity of droplets merging and shedding increase with the increase of the wetting gradient. The more hydrophilic the original surface, the better the optimization effect of accelerating drainage is by applying a wetting gradient. The radius and radius ratio significantly affect droplets merging and shedding on the gradient wetting surface. The larger the radius and radius ratio, the shorter the droplets merging and shedding time.

A new network-based community detection algorithm for disjoint communities

A community is a group of people that shares something in common. The definition of the community can be generalized as things that have common properties. By using this definition, community detection can be used to solve different problems in various areas. In this study, we propose a new network-based community detection algorithm that can work on different types of datasets. The proposed algorithm works on unweighted graphs and determines the weight by using cosine similarity. We apply a bottom-up approach and find the disjoint communities. First, we accept each node as an independent community. Then, the merging process is applied by using the modularity value as a stopping criterion. We use real datasets and evaluate the algorithm with modularity, normalized mutual information, and performance metrics. In addition, we test our algorithm by using central nodes. We also take into consideration the number of communities in the case they are known. The proposed algorithm has high modularity and accuracy in different datasets.

Battery-Aware Cooperative Merging Strategy of Connected Electric Vehicles Based on Reinforcement Learning With Hindsight Experience Replay

Cooperative control of connected and automated electric vehicles (CAEVs) offers a great potential for a safe, high-efficient, sustainable transportation system. Among them, coordinated on-ramp merging based on an on-ramp merging vehicle and a mainline facilitating is a hot spot to lighten the impact of shockwave on highway junctions. Reinforcement learning (RL) is a promising solution to address this problem for its strong adaptiveness and self-learning ability. The existing methods are dedicatedly designed to circumvent the sparse reward problem of long-term merging safety but restrict the optimization space and neglect individual costs, especially irreversible loss, such as battery aging. In this article, a hindsight experience replay RL coordinated freeway on-ramp merging frame is proposed to face the sparse reward problem in ramp merging problem and, meanwhile, co-optimize traffic efficiency, energy-saving, and battery health performance. Compared with the existing optimization-based strategy, it fundamentally avoids abundant expert knowledge and elaborate design for reward shaping and model construction while ensuring the nature of merging tasks without excessive simplification. Numerical experiments are conducted to verify the optimality, adaptability, and self-learning ability of the proposed strategy. With comparison experiment, the proposed strategy surpasses state-of-the-art RL methods more than 13% in overall index throughput with 12% energy consumption while easing individual battery aging during the merging process.

Game Theory-Based Ramp Merging for Mixed Traffic With Unity-SUMO Co-Simulation

Ramp merging is considered to be one of the major causes of traffic accidents and congestion due to its inherent chaotic nature. With the development of the connected and automated vehicle (CAV) technology, CAVs can conduct cooperative merging using communication, and can also handle complicated situations even with legacy vehicles. In this article, a game theory-based ramp merging strategy has been developed for the optimal merging coordination of CAVs in mixed traffic, which can determine the dynamic merging sequence and corresponding longitudinal/lateral control. This strategy improves the safety and efficiency of the merging process by ensuring a safe intervehicle distance and harmonizing the speeds of CAVs in the traffic stream. To verify the proposed strategy, mixed traffic simulation runs under different penetration rates and different congestion levels have been carried out on an innovative Unity-SUMO integrated platform, which connects a game engine-based driving simulator with a state-of-the-art microscopic traffic simulator. The results show that the average speed of traffic flow can be increased up to 210%, while the fuel consumption can be reduced up to 53.9%. In addition, the driving volatility can be stabilized to a level with 0% extreme values.

Hierarchical merger of primordial black holes in dwarf galaxies

We study the merger history of primordial black holes (PBHs) in a scenario where they represent the dominant dark matter component of a typical dwarf galaxies' core. We investigate the possibility of a sequence of collisions resulting in a hierarchical merger of black holes, and look at the final mass spectrum in such clusters, which initially present a monochromatic (single-mass) PBH population. Our study shows that the merging process results in the transfer of about 40% of the total mass of the core to the merger products regardless of the initial mass of PBHs, with about 5% of energy radiated out in the form of gravitational waves. We find that, in the lighter mass limit, black holes up to eight times more massive than the original population can be formed within a Hubble time.

중국 방언 속 비음 말음 합류 현상에 관한 고찰

Chinese linguists have long debated about the bifurcated direction of syllable-coda nasal mergers in Chinese dialects since 1970’s. Some believed that the merging process is unidirectional (anterior to posterior), but others asserted that alveolarization of nasal codas (-m>-n and -ŋ>-n) is the major trajectory. Previous experimental research not only discovered salient acoustic cues in perceiving nasal codas but also provided social implications of different patterns of the merger. However, they failed to make a reasonable prediction about the further direction of the merger in addition to a lack of phonology-based analysis. This research aims to analyze the merging process on the basis of Contrastive Hierarchy (CH) and Sisterhood Merger Hypothesis (SMH). First, we can think of two types of contrastive hierarchies: [Dorsal]>[Labial], [Labial]>[Dorsal] because of Markedness theory. A theory of Predicted Acquisition Sequences and the SMH make us choose the first hierarchy: [Dorsal]>[Labial]. In short, the alveolarization of the velar nasal coda will happen after the completion of the merger between the labial and velar ones. Previous research papers and the data of Chinese dialects both support the conclusion.

Classification of OME with Eardrum Otoendoscopic Images Using Hybrid-Based Deep Models, NCA, and Gaussian Method

Otitis media with effusion (OME) is defined as a middle ear disease that occurs with the accumulation of fluid in the posterior part of the eardrum, usually without any symptoms. When OME disease is not treated, some negative consequences arise that deeply affect the education, social and cultural life of the patient. OME disease is a difficult issue to diagnose by specialists. In this article, autoendoscopic images of the eardrum have been classified using deep learning methods to help specialists in the diagnosis of OME. In this study, a hybrid deep model based on artificial intelligence is proposed. In the proposed hybrid model, feature maps were obtained using Efficientnetb0 and Densenet201 architectures from both the original dataset and the improved dataset using the gaussian method. Then, the merging process was applied to these feature maps. Unnecessary features are eliminated by applying NCA dimension reduction to the combined feature map. The most valuable features obtained at the end of the optimization process are classified in different machine learning classifiers. The proposed model reached a very competitive accuracy value of 98.20% in the SVM classifier.