bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymptotic steady state of a dissipative long-range interacting spin system at finite temperature
Authors: Sadiek Gehad , Almalki Samaher 
Published: August 2023

Abstract
Many of the recently developed quantum systems that are considered promising candidates for the underlying technology of quantum computing enjoy long-range interaction, which is even tunable in some of them. Most of these systems can be described using the Heisenberg spin model to represent their interaction with the same system or a different one in hybrid structures. We consider here a finite two-dimensional spin system with a varying spin-spin long-range interaction under the effect of an external uniform magnetic field. We investigate the dynamics of the system and its asymptotic behavior at different degrees of anisotropy and interaction range under coupling to a thermal dissipative environment, starting from different initial states. We show that the system spin state and bipartite entanglement evolve in time to reach asymptotic values that are enhanced significantly by the degree of anisotropy and interaction range, whereas the thermal dissipative environment degrades the entanglement asymptotic equilibrium value as the temperature increases. Interestingly, while the robustness of the spin system against the environment’s thermal dissipative effects increases with the interaction range and degree of anisotropy, the entanglement between the far sites on the lattice shows its highest resilience in the partially anisotropic system, which might be attributed to a critical behavior taking place in the system. While the system’s early dynamics varies significantly depending on the initial state, the asymptotic equilibrium value is found to be completely independent.
Study of antiprotons as drivers in inertial confinement fusion by fast ignition method
Authors: Azizi Maryam , Khanbabaei Babak 
Published: August 2023

Abstract
Inertial confinement fusion is a promising approach to achieve controlled nuclear fusion for clean and abundant energy production. One of the key challenges in Inertial confinement fusion is achieving efficient ignition of the fusion fuel. Fast ignition offers a potential solution to this challenge by using an ultra-high intensity laser or a charged particle beam to directly ignite a pre-compressed fusion fuel. In this manuscript, we propose an approach for fast ignition in ICF, utilizing an antiproton beam to drive ignition in a deuteron-tritium fuel with a uranium-238 seed. The use of antiproton beams in Inertial confinement fusion offers unique advantages, including their ability to deposit energy deeply into the fuel, leading to enhanced energy coupling and heating. The addition of uranium-238 as a seed material in the fuel can further improve ignition conditions by enhancing energy deposition and facilitating ignition reactions. We present detailed simulations and analyses to demonstrate the feasibility and potential benefits of this approach. We investigate the effects of antiproton beam parameters, such as energy, intensity, and pulse duration, on ignition conditions, as well as the impact of uranium-238 seed concentration and distribution in the fuel. Our results show that fast ignition driven by an antiproton beam in DT with uranium-238 seed has the potential to significantly improve ignition performance in Inertial confinement fusion, leading to enhanced energy output and higher gain. The use of antiproton beams allows for efficient energy deposition and heating of the fuel, while the inclusion of uranium-238 seed promotes ignition reactions and improves ignition conditions. This concept presents a promising pathway towards achieving practical and efficient ignition in Inertial confinement fusion, and could pave the way for next-generation fusion power plants.
Reviewing the prospect of fermion triplets as dark matter and source of baryon asymmetry in non-standard cosmology
Authors: Biswas Anirban , Chakraborty Mainak , Khan Sarif 
Published: August 2023

Abstract
Indirect searches of Dark Matter (DM), in conjugation with 'missing track searches' at the collider seem to confine SU(2)
L
fermion triplet DM (FTDM) mass within a narrow range around 1 TeV. The canonical picture of the pure FTDM is in tension since it is under-abundant for the said mass range. Several preceding studies have reported that an extra species (ϕ), redshifts faster than the radiation (∼ a
(4+n) where n > 0), leads to a faster expanding early Universe by dominating in the energy density with an enhanced Hubble parameter. This has the potential to revive the under-abundant FTDM (ℤ2 odd, lightest generation) by causing freeze-out earlier without modifying the interaction strength between DM and thermal bath. On the other hand, although the CP asymmetry produced due to the decay of ℤ2 even heavier generations of the triplet remains unaffected, its evolution is greatly affected by the non-standard cosmology. It has been observed through numerical estimations that the minimum mass of the triplet, required to produce sufficient baryon asymmetry of the Universe (BAU), can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario. The non-standard parameters n and Tr
(a reference temperature below which radiation dominance prevails), which simultaneously control DM abundance as well as the frozen value of BAU, are tightly constrained from the observed experimental values. We have found that n is strictly bounded within the interval 0.4 ≲ n ≲ 1.8 where the upper bound is imposed by the BAU constraint whereas the lower bound arises to satisfy the correct DM abundance. It has been noticed that the restriction on Tr
is not so stringent as it can vary from sub GeV to a few tens of GeV.
Hunting the stochastic gravitational wave background in pulsar timing array cross correlations through theoretical uncertainty
Authors: Bernardo Reginald Christian , Ng Kin-Wang 
Published: August 2023

AbstractIncredible progress on the theoretical uncertainty of the spatial correlations of the stochastic gravitational wave (GW) background were recently made. However, it remains to realize the impact of this theoretical uncertainty on PTA cross correlations analysis. This paper pushes forward in this direction, as a proof-of-principle: showing the potential role that theoretical uncertainty has on unburying the stochastic GW background signal in noisy PTA cross correlation measurements. We consider both a mock data set and the noise-marginalized 12.5 years NANOGrav spatial correlation measurements, and find optimistic conclusions regardless of the physical content of the GW background and the nature of the noise in the data. Very briefly, we show through various cases a modest result that looking out for a stochastic signal is better when two of its moments are utilized. Or, in terms of GWs, we show that the theoretical uncertainty can play a substantial role in the hunt for the stochastic GW background.
Inflation caused by a potential valley with 𝖢𝖯 violation
Authors: Suematsu Daijiro 
Published: August 2023

Abstract
We propose an inflation scenario caused by an inflaton identified with a potential
valley which brings about CP violation in the standard model (SM).
If singlet scalars have nonminimal couplings with the Ricci scalar in a suitable way,
favorable inflation could be derived through the potential
valley composed of such scalars.
We study dynamics of the scalars during and after the inflation, which suggests
that it could be described as a single field inflation approximately.
If these scalars make suitable ingredients of the SM couple with
vectorlike fermions and
right-handed neutrinos, a CKM phase could be induced and also leptogenesis
could occur successfully even at a rather low reheating temperature.
Peaky production of light dark photon dark matter
Authors: Nakai Yuichiro , Namba Ryo , Obata Ippei 
Published: August 2023

Abstract
We explore a mechanism to produce a light dark photon dark matter through a coupling between
the dark photon field and a spectator scalar field which plays no role in
the inflationary expansion of the Universe while rolling down its potential during the inflation.
The motion of the spectator field efficiently produces dark photons with large wavelengths
which become non-relativistic before the time of matter-radiation equality.
The spectrum of the wavelengths is peaky
so that the constraint from the isocurvature perturbation can be evaded.
The correct relic abundance is then achieved over a wide range of the dark photon mass down to 10-13 eV.
Our mechanism favors high-scale inflation models which can be tested in future observations.
Furthermore, fluctuations of the dark photon field during inflation produce gravitational waves
detectable at future space-based interferometers and/or pulsar timing array experiments.
The AGN Feedback in Compact Galaxies: On the Impact of a More Massive Central Black Hole
Authors: Di Yihuan , Yuan Feng , Ji Suoqing 
Published: August 2023

Abstract
We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium, active galactic nuclei (AGN) feedback and black hole (BH) feeding in a massive compact galaxy, with an emphasis on the impact of different central BH masses. We find that with a more massive central BH, high-speed outflows are more prominent, and the gas fraction in the compact galaxy is reduced. Due to the lower gas density and higher gas temperature, the compact galaxy with a more massive BH (MAS galaxy) remains predominantly single-phase with the cooling time t
cool ≳ 100t
ff. In contrast, the compact galaxy with the reference BH mass (REF galaxy) maintains a higher gas fraction with a shorter cooling time, slightly more multiphase gas and less prominent outflows. We further demonstrate that the difference in gas thermal states and kinematics is caused by the stronger AGN feedback in the compact galaxy with a more massive BH, where the AGN wind power is twice as much as that with the reference BH. Since the AGN feedback efficiently suppresses the inflow rate and the BH feeding rate, the BH mass growth is significant in neither the compact galaxy with the reference BH nor that with the more massive BH, only by 24% and 11% of the initial BH mass, respectively, over the entire evolution time of 10 Gyr. We thus posit that without ex situ mass supply from mergers, the massive BHs in compact galaxies cannot grow significantly via gas accretion during the late phase, but might have already formed by the end of the rapid early phase of galaxy formation.
Motion analysis and power output optimization design of wave energy device
Authors: Chen Lijie , Liu Xiao , Yan Weimin , Shi Guoyong , Gao Zhibing , Huang Zexian 
Published: August 2023

Abstract
Wave energy is an essential marine renewable energy. Improving the energy conversion efficiency of wave energy devices is the key aspect of wave energy utilization research. This paper deals with the movement status of the wave energy device and its power optimization. Depending on Newton’s second law, the second-order ordinary differential equation model is established for the float and oscillator respectively. According to whether the damping coefficient is constant, the pending method coefficient is utilized to solve the general second-order solution ordinary differential equation model, and the drooping displacement and velocity graphs under different damping coefficients are obtained. The analysis shows that the oscillating wave energy device improved by the second-order ordinary differential equation model could become stable within a very short time. The motion displacement and velocity of the wave energy device at five random moments were taken to check the accuracy of the model, and the results show that the model has an excellent promoting effect on the motion state of the wave energy device at sea and reduces the depletion of the device in terms of accuracy of motion displacement and velocity.
Temporal and Spatial Variation Characteristics of Hydrodynamic Forces in Urban Shallow Lakes
Authors: Xiao Tingting , Yu Can , Zhang Kui , Zhang Ya , Zhang Qin 
Published: August 2023

AbstractTo study the temporal and spatial variation characteristics of hydrodynamic forces in Rule Lake, a two-dimensional mathematical model of shallow water lake was established based on MIKE 21, and the flow field characteristics of Rule Lake under the action of topography, wind field and inflow were simulated and analyzed. The results show that the spatial and temporal heterogeneity of hydrodynamics in the Rule Lake area is obvious, the velocity in the lake area presents a gradient change characteristic of high in the west and low in the east, and the velocity in the middle of the lake area is greater than that in the bends of shorelines on both sides of the lake area; Under the driving of wind field, there is a reverse circulation area in the lake area. The existence of the circulation area can disturb the dead water area at the shoreline bend and improve the local water mobility; The flow velocity in summer and autumn is slightly higher than that in spring and winter. It is suggested that during the operation and maintenance period, attention should be paid to the fluidity of the water body in the southwest of the lake area, the change in water quality and the timely removal of floating garbage on the water surface.
Hydrodynamic Performance of Soft Robotic Fish Actuated by Ionic Polymer-Metal Composite Pectoral Caudal Fin
Authors: Wu Jinxian , Chen Kun , Zhang Tian , Fu Yong 
Published: August 2023

Abstract
Soft robotic fish has a lot of benefits. This paper aims to create a robotic fish with a soft pectoral caudal fin which was powered by IPMC material. The soft robotic fish’s hydrodynamic performance during straight swimming is numerically computed using the overset grid approach. Compared with the soft tail fin driven with a driving frequency of 0.05 Hz and those driven together with three soft pectoral fins with different driving frequencies and amplitude, the hydrodynamic coefficients and pressure of the bionic robotic fish are analyzed. We can find the regions of distinct positive and negative pressure during the IPMC soft caudal fin flapping. And the forward pressure component provides forward propulsion for the bionic fish. The greater the flapping frequency of the IPMC soft pectoral fin is, the smaller the amplitude is, and the greater the drag force receives. It is concluded that while the driving frequency of soft pectoral fins is 0.05 Hz, the amplitude is 5.64 mm, and the soft pectoral fin driving effect is good. Further research into how soft pectoral caudal fin frequency and amplitude affect the hydrodynamic capabilities of bionic fish was also made.
The Influence of Different Diving Angles on the Hydrodynamic Noise of Submarine Enclosures
Authors: Lv Bangjun , Chen Yonghong 
Published: August 2023

Abstract
The hull is an important component of the submarine structure, and it is also one of the factors that affect the concealment of the submarine. By using the finite element method, a submarine model was established to analyze the hydrodynamic noise at the contact points between the front and rear of the hull and the hull under different diving angles. The results show that when the diving angle is about 10°, the hydrodynamic noise at the front and rear positions of the enclosure is relatively small. The research results provide a reference for ensuring the stealth operation conditions of submarines and have practical significance for improving the stealth of submarines.
The effect of seasonal variation of medium viscosity on centrifugal desanding in shaft seal water system of suction dredger: Numerical simulation and mechanism study
Authors: Tan Shaohuan , Wang Bingjie , Bai Zhishan 
Published: August 2023

Abstract
As a lubrication medium, the shaft-seal water often carries substantial sand particles in the cutter suction dredger, causing severe wear and tear of the internal components of the slurry pump. It has been proved that the shaft seal water system could be optimized by introducing a hydro cyclone to prolong the service life of the slurry pump. However, it was found that the seasonal variation of water viscosity would produce an obvious effect on the centrifugal separation of sand particles. Therefore, in this study, the influence of seasonal viscosity change on the flow field characteristics and sand particle separation was systematically studied by computational fluid dynamics (CFD). The simulation results showed that the fluid and pressure field in hydro cyclone has good symmetry under different viscosity. While with the increase of viscosity, the fluid resistance coefficient increases, resulting in a downward trend of turbulent kinetic energy and an upward trend of negative pressure zone, which is not conducive to sand particle separation. Moreover, to verify the consistency between simulation and actual industry, the grade efficiency of sand particles was studied and discussed. The average particle size of sand could be reduced from 37.8 μm to 8.1 μm, and the separation efficiency could reach 90% under better suitable dredging conditions (Salinity: 34%, Temperature: 20 °C). Further, the experimental and industrial results showed that the fish hook effect inevitably existed in practice due to the entrainment of coarse particles. This study would provide theoretical support for the subsequent optimization of the shaft seal water system.
Study on Influence of Flow Inertia of Pressure Pipe on Critical Stable Sectional Area of Surge Tank
Authors: Li Gaohui , Yang Shaojia , Cui Weijie , Xue Kaizhen 
Published: August 2023

Abstract
In the process of calculating the analytical formula of the critical stable section area of the surge tank, the influence of the time constant of the flow inertia in the pressure pipe is ignored by all the formulas, including Thoma’s formula and the E/N correction formula. In this paper, a fifth-order analytical model of a hydraulic turbine generator set with a surge tank is established after considering the inertia of the flow in the pressure pipe. Then, the relationship between the flow inertia in the pressure pipe and the critical stable section area of the surge tank is systematically analyzed by using this fifth-order analytical model. Finally, combined with a typical hydropower station, the influence of flow inertia of the pressure pipe on the stable section of the surge tank caused by the changes of head, flow and the length of the pressure channel is analyzed.
Design and Seakeeping Performance of a Shallow-sea Surface Litter Collection Device
Authors: Zhang Xiangyu , Zhang Sheng , Lei Yu , Zheng Xiangyuan 
Published: August 2023

Abstract
In recent years, the pollution of ecological waters, especially the litter floating on the ocean surface, has emerged as a pressing economic, political, and environmental concern of the international society. The development of a widely applicable, safe, reliable and cost-saving marine surface litter collection device has drawn considerable attention. In this paper, an innovative shallow-sea floating surface litter collection device (later referred to as SFSLCD) is proposed first, including its concept design, dimensions and key parameters, working scheme, and mooring system. Second, the hydrostatic and hydrodynamic characteristics of SFSLCD are derived through numerical modeling. Last, the safety of SFSLCD in normal and rough sea states is validated in terms of its good seakeeping performance using the coastal condition of Dapeng Bay, Shenzhen, China. It is proven that this litter collection device equipped with photovoltaic panels to supply power can operate in waters of depth between 5 and 15 m in seas, rivers and lakes.
Unsteady Simulation and Mode Analysis of Disturbed Cylinder Flow
Authors: Gong Ziqiao 
Published: August 2023

Abstract
The unsteady simulation of cylinder flow with inlet velocity disturbance is simulated and compared with that without disturbance. POD is adopted to analyze and capture the dominant modes of the vortex street in the cylinder wake. The results show that the POD method is efficient in reconstructing the flow field. When the inlet velocity disturbance exists, the number of modes required to reconstruct the flow field accurately is almost unchanged, but the energy proportion of each mode changes. The larger the disturbance frequency is, the smaller the shape and vorticity magnitude of the vortex street is, and the slower the generation speed is. If the frequency deviates too much from the original frequency of the flow field, the effect of inlet velocity disturbance will be shielded.
Numerical simulation study on noise pollution of the solenoid valve in pressure water-air system of pumped storage power station
Authors: Long Zhe , Shu Lingfeng , Li Chengjun , Zheng Yingxia , Huang Jingqian 
Published: August 2023

Abstract
To explore the noise problem of the solenoid valve in the pressurized water-air system of a pumped storage power station when operating under the discharge condition, a full-channel unsteady numerical simulation was carried out on the medium-pressure gas storage tank and its discharge facilities. Firstly, the large eddy simulation (LES) method was used to calculate the sound source, and then the finite element method (FEM) was used to solve the internal sound field. The flow field and sound field distribution of the solenoid valve in the pressure water-air system are analyzed in detail. Then the near-field noise analysis method is used to trace the source of the noise problem of the solenoid valve. Finally, according to the noise intensity distribution, the location of the noise source and the noise mechanism is clarified, which provides the basis for the selection of a technical route for the subsequent optimization design of the solenoid valve in the exhaust pressure water system.
Study on Hydrodynamics of Fish-Friendly Open-Channel Flow
Authors: Jiang Dingguo , Lu Peng , Gao Huan , Yang Ji 
Published: August 2023

Abstract
To elucidate the hydrodynamic characteristics of a fish-friendly open channel, a three-dimensional numerical hydrodynamic model is constructed in this study employing the Large-eddy Simulation (LES) technique. The reliability of this numerical model is thoroughly validated by incorporating periodic boundaries in the flow direction, allowing for the recurrent development of water flow within the computational domain and utilizing experimental data from a flume. The results demonstrate that the fish-friendly channel is partitioned into a high-velocity mainstream zone and a low-velocity habitat zone. The time-averaged flow velocity in the mainstream zone is approximately 2.0 times the cross-sectional average flow velocity. In the low-velocity habitat zone, the average hourly flow velocity and turbulence are at a relatively low level, rendering the zone suitable for fish habitation and the incubation of adhesive fish eggs. A significant vortex structure is present in the mixing layer at the junction of the main flow area and the habitat area, which not only markedly increases the turbulence intensity but also serves as the primary driver of momentum exchange within the open channel.