bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular dynamics simulation of thermal properties of modified graphene / n-octadecane composite phase change material
Authors: Li J , Mao Y , Yang X , Liao Y N , Cai D , Chen S S , Sun K , Zheng Y J 
Published: May 2024

Abstract
Phase change materials have been widely used in building energy-saving and off-peak energy storage systems, but most phase change materials limit their application because of their low thermal conductivity. Improving their heat transfer performance and revealing the heat transfer mechanism from a microscopic perspective are the keys to practical applications. The PCM system composed of n-octadecane and modified graphene was established by molecular dynamics simulation and the influence of macro thermal properties was analyzed from a microscopic perspective including end-to-end distance and torsional angle distribution, radial distribution function, and self-diffusion coefficient. The results show that the thermal conductivity of PCMS increases with increased modified graphene content. When the mass fraction is 26.88%, the thermal conductivity increases by 44.5%, which is consistent with the trend of experimental values. The addition of modified graphene resulted in a more concentrated distribution of n-octadecane molecules, indicating that the arrangement of n-octadecane molecules was affected, increasing the thermal conductivity of n-octadecane. The deviation of phase transition temperature from the experimental value is less than 1%.
Direct formation of nano-scale dislocation loops during displacement cascade in BCC Fe studied by molecular dynamics simulation
Authors: Cao Han , He Xinfu , Wu Shi , Wang Dongjie , Jia Lixia , Dou Yankun , Yang Wen 
Published: May 2024

Abstract
In this work, the displacement cascades in bcc iron were simulated by molecular dynamics (MD). The formation of dislocation loops was found in cascade simulations when the energy of PKA (EPKA) was above 20 keV. For the first time, we reported the formation of <100> interstitial dislocation loops in cascade simulation of bcc iron under low EPKA, about 40 keV, much lower than that in Ref. 10. On the other hand, our results suggest that <100> loops all transformed into 1/2<111> loops within 200 ps. This will help us build a microscopic image and mechanism about the formation of interstitial dislocation loop.
Transient growth of wavelet-based resolvent modes in the buffer layer of wall-bounded turbulence
Authors: Ballouz Eric , Dawson Scott T. M. , Jane Bae H. 
Published: May 2024

Abstract
In this work, we study the transient growth of the principal resolvent modes in the minimal flow unit using a reformulation of resolvent analysis in a time-localized wavelet basis. We target the most energetic spatial wavenumbers for the minimal flow unit and obtain modes that are constant in the streamwise direction and once-periodic in the spanwise direction. The forcing modes are in the shape of streamwise rolls, though pulse-like in time, and the response modes are in the form of transiently growing streaks. We inject the principal transient forcing mode at different intensities into a simulation of the minimal flow unit and compare the resulting nonlinear response to the linear one. The peak energy amplification scales quadratically with the intensity of the injected mode, and this peak occurs roughly at the same time for all forcing intensities. However, the larger energy amplification intensifies the magnitude of the nonlinear terms, which play an important role in damping the energy growth and accelerating energy decay of the principal resolvent mode. We also observe that the damping effect of the nonlinearities is less prominent close to the wall. Finally, we find that the principal resolvent forcing mode is more effective than other structures at amplifying the streak energy in the turbulent minimal-flow unit. In addition to lending support to the claim that linear mechanisms are important to near-wall turbulence, this work identifies time scales for the nonlinear breakdown of linearly-generated streaks.
Turbulent activity in the near-wall region of adverse pressure gradient turbulent boundary layers
Authors: Gungor Taygun R , Maciel Yvan , Gungor Ayse G 
Published: May 2024

Abstract
Two direct numerical simulation (DNS) databases are investigated to understand the effect of the outer-layer turbulence on the inner layer’s structures and energy transfer mechanisms. The first DNS database is the non-equilibrium adverse-pressure-gradient (APG) turbulence boundary layer (TBL) of Gungor et al. [1]. Its Reynolds number and the inner-layer pressure gradient parameter reach above 8000 and 10, respectively. The shape factor spans between 1.4 and 3.3, which indicates the flow has various velocity defect situations. The second database is the same flow as the first one but the outer layer turbulence is artificially eliminated in this flow. Turbulence is removed above 0.15 local boundary layer thickness. For the analysis, we chose four streamwise positions with small, moderate, large, and very-large velocity defect. We compare the wall-normal distribution of Reynolds stresses, two-point correlations and spectral distributions of energy, production and pressure strain. The results show that the inner layer turbulence can sustain itself when the outer-layer turbulence does not exist regardless of the velocity defect or the pressure gradient. The two-point correlations of both cases show that outer large-scale structures affect the inner layer structures significantly. The streamwise extent of the correlation contours scales with pressure-viscous units. This shows the importance of the pressure gradient’s effect on the inner-layer structures. The spectral distributions demonstrate that the energy transfer mechanisms are probably the same in the inner layer regardless of the velocity defect, which suggests the near-wall cycle may exist even in very-large defect APG TBLs where the mean shear in the inner layer is considerably lower than small-defect APG TBLs.
Coherence analysis of geophysical wakes in flow past a three-dimensional hill
Authors: Liu Jinyuan , Sarkar Sutanu 
Published: May 2024

Abstract
Wakes generated by topographies are ubiquitous in nature. The formation and evolution mechanism of wake-generated eddies is essential to understanding the effect of topography on oceanic bottom flow. In this study, we analyze the temporally resolved numerical database [1] of stratified wakes past an isolated three-dimensional hill, via proper orthogonal decomposition (POD) of the vertical vorticity field. We study the dynamics of the near wake (x/D < 3) and the far wake (x/D ≥ 3) separately, where x is the downstream distance from the center of the hill. The aim is to understand how rotation influences the change of coherence from the near to the far wake and also the coherence across heights.
Energy transfer in the formation and evolution of energy-containing motions in turbulent boundary layers
Authors: Matas Antonio , Liu Kevin , Kannadasan Ezhilsabareesh , Atkinson Callum , Soria Julio 
Published: May 2024

Abstract
This paper examines using direct numerical simulation (DNS) the recovery of the energy-containing scales of motion (energy-containing motions) when these are removed at the inflow boundary condition of a flat plate zero-pressure gradient turbulent boundary layer (ZPG-TBL). The energy-containing motions are identified from the spanwise spectral energy density of the interscale turbulent transport. Analysis of the resulting spanwise spectral energy densitiy of velocity and vorticity suggests that near-wall streaks are the initial energy-containing motions formed with quasi-streamwise vortices only developing further downstream. This result is in agreement with the previous study on turbulent channel flows by Kannadasan et al. [1].
Temporal vortex tracking in isotropic turbulence
Authors: Ghira Afonso A. , Vela-Martin Alberto , Da Silva Carlos B. 
Published: May 2024

Abstract
An algorithm to allow the temporal vortex tracking of the intense vorticity structures is introduced and applied to direct numerical simulations (DNS) of homogeneous isotropic turbulence (HIT). The algorithm allows the identification of the individual life events of the worms, including events of splits into several structures and of merging between different structures. Results obtained from a relatively small DNS, with Taylor based Reynolds number equal to Reλ
= 54, for a simulation lasting more than 6 integral time scales, shows that the complement of the CDF of the life time of the IVS is well approximated by an exponential distribution function. The mean life time of the IVS which is approximately 3.6τη
, where τη
is the Kolmogorov time, and the birth rate of these structures is close to 4.5/τη
(number of new structures per Kolmogorov time). A population model is built to predict the number of existing structures at any time, which gives a number of existing IVS equal to ≈ 16, which agrees well with the results from the DNS.
Coherent structure tracking of the second Mack mode in transitional hypersonic boundary layers
Authors: Hammachi Riwan , Piot Estelle , Deniau Hugues , Brazier Jean-Philippe , Daviller Guillaume , Cardesa José I. 
Published: May 2024

Abstract
The natural transition of hypersonic boundary layers (HBLs) is often expressed in terms of discrete modes and their linear stability. A frequent interpretation revolves around fast and slow acoustic modes interacting in the vicinity of the vortical/entropic branches of the continuous spectrum found from stability analyses. Yet several transition scenarios are contingent upon factors such as the spectral content of the free-stream disturbances, or the interactions between the discrete modes within the boundary layer and the free-stream disturbances near the leading edge which can be decomposed into vortical, acoustic and entropic nature based on the fluid-thermodynamic (FT) components. Yet the interpretations of linear stability applied to discrete modes can lead to semantic conflicts with the terminology of FT components. To clarify the current description of the processes involved, this study chooses an approach aimed at characterizing the dynamics of the second Mack mode in transitional HBLs through coherent structure tracking. The method involves decomposing the flow perturbations into acoustic, vortical and entropic content, and following their associated coherent structures over time. For this purpose, direct numerical simulations are carried out to investigate the dynamics of the second Mack mode instability in two-dimensional HBLs, considering a flow at Mach 6 over a cooled and an insulated wall. It is found that vortical structures coexist at different heights along the wall surface, forming alternating sign doublets around the critical layer and above the relative sonic line. These structures are found to merge in the region of maximum second Mack mode instability.
Causality between streaks and bursts in wall-bounded turbulence
Authors: Ling Yuenong , Lozano-Durán Adrian 
Published: May 2024

Abstract
We use an information-theoretic method, referred to as information flux, to quantify the causal relationships between streaks and bursts in a non-intrusive manner. Within this framework, causality is quantified as the flux of Shannon information from the present of the quantities of interest to their future. We also use the so-called information leak to measure the information that is not accounted for due to unobserved variables. We investigate data from a direct numerical simulation of turbulent channel flow at the friction Reynolds number Re

τ

≈ 180. The spatial distribution of causality is investigated as two time scales based on 50% value of the information leak and maximum of the normalized cross-induced information flux. It is found that the most causal spatial configuration for streaks and bursts is always streamwise-aligned. Furthermore, four dominant causal spatial configurations between streaks and bursts are identified. At the short time scale around 10 viscous units (when information flux is 50%), streaks and bursts have comparable causality to one another. At the longer time scale (corresponding to the maximum cross-induced causality), there is greater causality from streaks to bursts.
Inter-scale Causality Relations in Wall Turbulence
Authors: De Salis Young J , Hao Z , Garcia-Mayoral R 
Published: May 2024

Abstract
We investigate the inter-scale energy transfer in the buffer layer between different streamwise and spanwise lengthscales. In a periodic channel, inter-scale transfer of momentum in the periodic directions is only possible through wavenumber interactions in the non-linear advection term. The aim of this study is to map the inter-scale interactions which transfer energy through advection to different lengthscales of interest. The non-linear advection term has nine contributions, which correspond to three different advecting and advected velocity components. Because the flow is anisotropic, each of these contributions can be viewed as portraying a different physical mechanism. Maps of inter-scale transfer are therefore constructed for each of the nine contributions to the advection term in order to understand the relative importance of advecting and advected velocity components in wall turbulence. As a preliminary exploration, two maps of the inter-scale energy transfer in the buffer layer are presented for Reτ
= 180, one for transfer to a ‘target’ lengthscale dynamically relevant in the near-wall cycle,

λ

x

+

=
188

,

λ

z

+

=
94

and one for transfer to a ‘target’ lengthscale in the dissipative range,

λ

x

+

=
42

,

λ

z

+

=
21

. In the first case, we observe that the transfer of energy is dominated by transfer into streamwise-velocity (u) by spanwise-elongated structures of spanwise-velocity (w) that advect streamwise-elongated structures of streamwise-velocity (u). This is nothing but the process of streak meandering induced by spanwise-elongated (w) structures. In the second case, the inter-scale transfer can be split into three dominant mechanisms. The first and second mechanisms are observed across many of the nine contributions to the advection term. Velocity structures with size similar or larger than streamwise streaks either advect (mechanism 1) or are advected by (mechanism 2) velocity structures with lengthscales close to the target one. The third mechanism is only significant for streamwise (u) velocity structures advecting streamwise (u) and spanwise (w) velocity, and involves structures with an intermediate scale which is in-between the dissipation scale and the near-wall cycle dynamic lengthscale, but still in the dissipation range. In this mechanism, intermediate-scale streamwise-velocity structures advect intermediate-scale streamwise- and spanwise-velocity structures.
Adaptivity of a leaf-inspired wind energy harvester with respect to wind speed and direction
Authors: Sabzpoushan Seyedali , Woias Peter 
Published: May 2024

Abstract
Environmental wind is a random phenomenon in both speed and direction, though it can be forecasted to some extent. An example of that is a gust which is an abrupt, but short-time change in wind speed and direction. Being a free and clean source for small-scale energy scavenging, attraction of wind is rapidly growing in the world of energy harvesters. In this paper, a leaf-like flapping wind energy harvester is introduced as the base structure in which a short-span airfoil is attached to the free end of a double-deck cantilever beam. A flap mechanism inspired by scales on sharks’ skin and a tail mechanism inspired by birds’ horizontal tail are proposed for integration to the base harvester to make it adaptive with respect to wind speed and direction, respectively. The use of the flap mechanism increases the leaf flapping frequency by +2.1 to +11.5 Hz at wind speeds of 1.5 to 6.0 m s−1. Therefore, since the output power of a vibrational harvester is a function of vibration frequency, a figure of merit or an efficiency parameter related to the output power will increase, as well. On the other hand, if there is a misalignment between the harvester’s heading and wind direction due to change of the latter one, the harvesting performance deteriorates. Although the base harvester can realign in certain ranges of sideslip angle at each wind speed, when the tail mechanism is integrated into that, it broadens the range of realignable sideslip angles at all the investigated wind speeds by up to 80

∘

.
Adaptation, Mitigation and Resilience: Learning from the Coastal and Surrounding Communities Forest
Authors: Sylviani  , Sakuntaladewi N 
Published: May 2024

Abstract
Climate change can affect seasonal patterns in a region and result in extreme weather conditions, thereby significantly impacting the lives of communities, especially those heavily dependent on the surrounding ecosystems such as fishermen and forest-dwelling farmers. They must continually adapt to the seasonal patterns and extreme weather to ensure their survival. This article discusses the impacts of seasonal changes, adaptation strategies, and community vulnerability, particularly among those residing in coastal areas and near forests. The method employed involves evaluating several research findings and reviews summarized in a discussion. The study’s findings indicate that climate change prompts communities to take reactive and anticipatory actions. Coastal communities, especially fishermen, adapt to seasonal changes by adjusting fishing schedules and modifying fishing equipment, improving embankments, tertiary water channels, culverts for water gate enhancements, and planting mangroves on embankments to reinforce them and along the coast to protect their fishponds. Communities reliant on forests adapt to seasonal changes by adjusting planting times and crop varieties to align with local seasonal characteristics. This adaptive ability ensures their access to food supplies and resilience against climate change. The implications of adaptation to seasonal changes can change the lifestyle of coastal communities and those around forests.
Semendo Coffee Development and Partnership Strategy to Enhance Governance for Food Security and Climate Change Mitigation
Authors: Hanapi S , Malau L R E , Laksono P , Alfayanti  , Ulya N A , Hutapea Y , Damayanti E C , Fitriani Y , Anita Y , Saisan D G M 
Published: May 2024

Abstract
Semendo coffee is a major income source for agricultural households in the Semendo region. Agroforestry is commonly employed practice at numerous Semendo coffee plantations. Timber and Multipurpose Tree Species widely cultivated to provide shade. This study examines Semendo coffee’s governance-enhancing development and collaboration methods. SWOT (strength, weakness, opportunities, threats) and AHP (analytic hierarchy process) analysis are used to determine the most suitable governance strategies and policies for Semendo coffee development. The data was gathered from key persons who possess expertise and serve as representatives for pertinent stakeholders and commercial entities throughout the Semendo coffee supply chain. SWOT analysis shows that the Strength-Opportunity (SO) strategy could improve Semendo coffee governance. High-quality coffee production, relevant party cooperation, and marketing network expansion are the proposed strategies. The AHP says mutual need drives partnership decision-making the most. Plasma-core partnerships are best for creating a strong sense of mutual need. Integration of the SO strategy with the core-plasma partnership is proposed to improve Semendo coffee governance. Agroforestry in Semendo coffee production can produce fruits and sequester carbon, reducing climate change. Agroforestry-based Semendo coffee management is expected to improve food supply, distribution, and consumption. This development is expected to maintain environmental integrity, notably in climate change mitigation.
Optimizing the role of rice central market in Java, Indonesia: the effect of toll roads construction to the rice market integration
Authors: Dharmawan Budi , Dumasari  , Nasir Muh Amat , Aisyah Dinda Dewi 
Published: May 2024

Abstract
Rice is considered as the primary staple food that Indonesian people mostly consume on daily basis. The need of rice in Indonesia is always increasing. However, the production of rice in Indonesia has not meet its demand. One of the factors resulting the number of paddy field decreasing is the construction of toll roads. The government of Indonesia has invested intensely in the development of a toll road network. The length of toll road operation has increased from around 750 km in 2014 to over 2,500 km in 2022. The construction encroaching paddy fields and resulting the production of rice decreasing every year. The paper objective is to investigate the implications of toll road investment to the rice market integration by focusing on Java as the central rice-producing region in Indonesia. We used the Vector Error Correction Model (VECM) approach to analyze the long-ranging daily rice price data series. The result of the study found that Cipinang Central Market in Jakarta has not the significant spatial market integration with rice markets in Java. Despite the fact that West Java, East Java, and Central Java with Cipinang Central Market have a major business tie, prices are not increasing. This shows a severe lack of market integration. The phrase “optimal market integration” refers to a more efficient market, especially when it comes to establishing rice market prices.
The estimation of above-ground oil palm carbon stocks of different ages through vegetation index
Authors: Prastowo Erwin , Andari Masyitah Tri , Hakim Arif Rakhman 
Published: May 2024

Abstract
Above-ground carbon stocks play an important role to support the sustainability of oil palm plantation, and vary with soil characteristics, climate conditions, and agronomic practices. The common direct approach to assess aboveground carbon stocks may be time-consuming, and laborious, so may not be suitable especially for large scale observation. Therefore, the use of remote sensing may overcome some limitations coming up for conventional methods, yet requires a considerable data validation to obtain a reliable model. In this study, the normalized difference vegetation index (NDVI) based on Sentinel-2 satellite imagery, acquired in September 2023, was used in combination with field measurements, i.e. biomass estimation, investigated in three separated of oil palm plantations differing in ages, i.e. young (< 10 years), middle (10 – 20 years) and old (> 20 years), subjected with similar soil characteristics, and climate condition, in Bojong Datar, Cibungur, and Cikasungka, West Java. Results show that above-ground carbon stocks increase with oil palm ages, i.e. from young to middle ages, with value ranging from 3.40 – 65.70 ton/ha, yet decreases down to 17 ton/ha with ages > 20 years. Similarly, it also occurred for NDVI index, i.e. increase from 0.50 – 0.59 for young to middle of oil palms, and down to 0.51 for oil palm > 20 years old. This study suggests a strong correlation between carbon stocks and NDVI values (R2 = 0.878), pointing out the potential use of vegetation index to estimate above-ground oil palm carbon stocks. In the future, with further validation, the use of NDVI to estimate plant biomass may provide a potential substitute for the field measurement methods with a considerable higher efficiency and accuracy.