bluuebunny/crossref_metadata_2025 huggingface dataset:
Excitation lifetime extracted from electron–photon (EELS-CL) nanosecond-scale temporal coincidences
Authors: Varkentina Nadezda , Auad Yves , Woo Steffi Y. , Castioni Florian , Blazit Jean-Denis , Tencé Marcel , Chang Huan-Cheng , Chen Jeson , Watanabe Kenji , Taniguchi Takashi , Kociak Mathieu , Tizei Luiz H. G.
Published: December 2023

Electron–photon temporal correlations in electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) spectroscopies have recently been used to measure the relative quantum efficiency of materials. This combined spectroscopy, named cathodoluminescence excitation (CLE) spectroscopy, allows for the identification of excitation and decay channels, which are hidden in average measurements. Here, we demonstrate that CLE can also be used to measure excitations' decay time. In addition, the decay time as a function of the excitation energy is measured, as the energy for each electron–photon pair is probed. We used two well-known insulating materials to characterize this technique, nanodiamonds with NV0 defects and hexagonal boron nitride (h-BN) with 4.1 eV defects. Both also exhibit marked transition radiations, whose extremely short decay times can be used to characterize the instrumental response function. It is found to be typically 2 ns, in agreement with the expected limit of the EELS detector temporal resolution. The measured lifetimes of NV0 centers in diamond nanoparticles (20–40 ns) and 4.1 eV defect in h-BN flakes (<2 ns) match those reported previously.
Sputtering from rough tungsten surfaces: Data-driven molecular dynamics simulations
Authors: Shermukhamedov Shokirbek , Probst Michael
Published: December 2023

The sputtering of tungsten surfaces caused by hot plasma particles is an important process in fusion reactors where divertors are typically made of tungsten sheets. In this study, we present a molecular dynamics simulation strategy to investigate the sputtering yields of tungsten surfaces with geometrical defects. This should serve as a model for non-monocrystalline surfaces in general and could also be a rough model for nanoscale “fuzzy” layers, which are known to be formed by surface bombardment with energetic particles. Using a non-cumulative approach, we simulate the irradiation of tungsten surfaces with cone-shaped, cylindrical, and spherical defects by argon atoms. We analyze the sputtering yields as functions of particle energy and defect sizes. As a result, we find that surfaces with distinctly shaped defects always exhibit reduced sputtering yields, compared to smooth ones. We also investigate the angular distributions of sputtered particles and find them mostly to be in accordance with prior experimental and computational results.
Reworking the Tao–Mo exchange–correlation functional. II. De-orbitalization
Authors: Francisco H. , Cancio A. C. , Trickey S. B.
Published: December 2023

In Paper I [H. Francisco, A. C. Cancio, and S. B. Trickey, J. Chem. Phys. 159, 214102 (2023)], we gave a regularization of the Tao–Mo exchange functional that removes the order-of-limits problem in the original Tao–Mo form and also eliminates the unphysical behavior introduced by an earlier regularization while essentially preserving compliance with the second-order gradient expansion. The resulting simplified, regularized (sregTM) functional delivers performance on standard molecular and solid state test sets equal to that of the earlier revised, regularized Tao–Mo functional. Here, we address de-orbitalization of that new sregTM into a pure density functional. We summarize the failures of the Mejía-Rodríguez and Trickey de-orbitalization strategy [Phys. Rev. A 96, 052512 (2017)] when used with both versions. We discuss how those failures apparently arise in the so-called z′ indicator function and in substitutes for the reduced density Laplacian in the parent functionals. Then, we show that the sregTM functional can be de-orbitalized somewhat well with a rather peculiarly parameterized version of the previously used deorbitalizer. We discuss, briefly, a de-orbitalization that works in the sense of reproducing error patterns but that apparently succeeds by cancelation of major qualitative errors associated with the de-orbitalized indicator functions α and z, hence, is not recommended. We suggest that the same issue underlies the earlier finding of comparatively mediocre performance of the de-orbitalized Tao–Perdew–Staroverov–Scuseri functional. Our work demonstrates that the intricacy of such two-indicator functionals magnifies the errors introduced by the Mejía-Rodríguez and Trickey de-orbitalization approach in ways that are extremely difficult to analyze and correct.
Nonlinear dynamics of large-amplitude, small-scale Alfvén waves
Authors: Mallet Alfred
Published: December 2023

We study large-amplitude, very oblique Alfvén waves at low β, with small gradient length scales, comparable to the ion inertial scale di. Such waves have large density fluctuations and slight dispersion from finite-frequency and finite-ion sound radius effects. We derive a weakly nonlinear evolution equation governing the behavior of the waves in one dimension and categorize the different solitons appearing in different regimes: the regular solitons involve full rotations of the transverse magnetic field similar to modified Korteweg–de Vries (mKdV) solitons (our nonlinear equation reduces to the mKdV equation in the long-wavelength limit). However, for sufficiently small soliton widths, some become singular, small-amplitude solitons with density discontinuities and, are, thus expected to become strongly dissipative in a real plasma. These solutions may be useful in explaining some aspects of the sharp, ion-scale magnetic field rotations (switchbacks) observed in the near-Sun solar wind by Parker Solar Probe.
Epitaxial growth of Si thin films with hexagonal close-packed structures on metal substrates
Authors: Wang Hao , Li Zuo , Sun Kai , Tao Minlong , Yao Gang , Zhu Huaxing , Wang Junzhong
Published: December 2023

We have studied the epitaxial growth of Si thin films on the Cd(0001) surface using low-temperature scanning tunneling microscopy. When deposited at low temperatures (100 K), Si atoms form dendritic islands with triangular shapes, indicating the existence of anisotropic edge diffusion in the process of Si film growth. After annealing to elevated temperatures, the triangular dendritic Si islands become hexagonal compact islands. Moreover, the 2D Si islands located on two different substrate terraces exhibit different heights due to the influence of quantum-well states in Cd(0001) films. Based on high-resolution scanning tunneling microscopy images, it is observed that the first, second, and third Si layers show the pseudomorphic 1 × 1 structure. In particular, the first and second layer islands reveal the opposite triangles, indicating the hexagonal close-packed stacking of Si atoms. These results provide important information for the growth of pristine Si films on metal substrates and the understanding of Si–metal interaction.
Dynamics of single bubble ascension in stagnant liquid: An investigation into multiphase flow effects on hydrodynamic characteristics using computational simulation
Authors: Al-Gaheeshi Asseel M. Rasheed , Rashid Farhan Lafta , Mohammed Hayder I.
Published: December 2023

Industrial operations often involve multiphase flows, where the motion of bubbles plays a crucial role in determining hydrodynamic properties. In the context of modern practices, advanced computational solvers are increasingly employed to simulate the interactions and trajectories of bubbles within complex flows. This study stands out in its unique examination of the computational software COMSOL's capability to accurately simulate the upward motion of a single bubble within quiescent water, akin to a liquid-like environment. The novelty lies in the comprehensive coverage of various container diameters (ranging from 10 to 80 mm) and heights (from 25 to 300 mm) relative to the air bubble diameter (ranging from 0.5 to 8 mm). Through meticulous comparisons between nine empirical formulas and numerically projected bubble ascent through a water column, a remarkable level of agreement emerges, underscoring the precision and consistency of the simulations. These simulations unveil intriguing findings, shedding light on the intricate interplay of forces governing bubble behavior. Notably, variations in drag forces induce changes in bubble shapes as a function of diameter, while the ascent of bubbles is accompanied by distinctive vortices, resulting in fascinating asymmetry. Furthermore, vorticity concentrates within the bubble, particularly in lighter fluid regions characterized by reduced pressure. The study also unveils how larger aspect ratios minimize flow drag, consequently boosting ascent velocities, and demonstrates the influence of container diameter on the rising velocity. Gravitational forces are found to reduce ascent velocities at greater column heights, while the rate of air bubble rise escalates with its size. This meticulous exploration of bubble dynamics in multiphase flows yields invaluable insights for diverse industrial applications, ultimately enhancing our understanding of this complex phenomenon. The strong alignment observed between empirical formulations and numerical simulations within the COMSOL framework underscores the utility of such computational tools for the study and design of multiphase flows' intricate dynamics.
Particle dispersion and clustering in surface ocean turbulence with ageostrophic dynamics
Authors: Maalouly Michael , Lapeyre Guillaume , Cozian Bastien , Mompean Gilmar , Berti Stefano
Published: December 2023

Upper-ocean turbulent flows at horizontal length scales smaller than the deformation radius depart from geostrophic equilibrium and develop important vertical velocities, which are key to marine ecology and climatic processes. Due to their small size and fast temporal evolution, these fine scales are difficult to measure during oceanographic campaigns. Instruments such as Lagrangian drifters have provided another way to characterize these scales through the analysis of pair-dispersion evolution and have pointed out striking particle convergence events. By means of numerical simulations, we investigate such processes in a model of surface-ocean turbulence that includes ageostrophic motions. This model originates from a Rossby-number expansion of the primitive equations and reduces to the surface quasi-geostrophic model, a paradigm of submesoscale dynamics, in the limit of vanishing Rossby number. We focus on the effect of the ageostrophic dynamics on the pair-dispersion and clustering properties of Lagrangian tracer particles at the ocean surface. Our results indicate that while over long times the pair separation process is barely affected by the ageostrophic component of the velocity field, the latter is responsible for the formation of temporary particle aggregates, and the intensity of this phenomenon increases with the Rossby number. We further show that Lagrangian tracers preferentially accumulate in cyclonic frontal regions, which is in agreement with observations and other more realistic modeling studies. These findings appear interesting to improve the understanding of the turbulent transport by ocean fine scales and in light of upcoming, new high-resolution satellite data of surface velocity fields.
Optimizing flow control with deep reinforcement learning: Plasma actuator placement around a square cylinder
Authors: Yousif Mustafa Z. , Kolesova Paraskovia , Yang Yifan , Zhang Meng , Yu Linqi , Rabault Jean , Vinuesa Ricardo , Lim Hee-Chang
Published: December 2023

This study introduces a deep reinforcement learning-based flow control approach to enhance the efficiency of multiple plasma actuators on a square cylinder. The research seeks to adjust the control inputs of these actuators to diminish both drag and lift forces on the cylinder, ensuring flow stability in the process. The proposed model uses a two-dimensional direct numerical simulation of flow past a square cylinder to represent the environment. The control approach involves adjusting the AC voltage across three specific configurations of the plasma actuators. Initially tested at a Reynolds number (ReD) of 100, this strategy was later applied at ReD of 180. We observed a 97% reduction in the mean drag coefficient at ReD = 100 and a 99% reduction at ReD = 180. Furthermore, the findings suggest that increasing the Reynolds number makes it harder to mitigate vortex shedding using plasma actuators on just the cylinder's rear surface. However, an optimized configuration of these actuators can fully suppress vortex shedding under the proposed control scheme.
Ultrafast photoinduced carrier transfer dynamics in monolayer MoS2/graphene heterostructure
Authors: Liu Ben , Yan Lihe , Si Jinhai , Shen Yanan , Hou Xun
Published: December 2023

Two-dimensional molybdenum disulfide (MoS2) has been proved to be a good candidate in photodetectors, and MoS2/graphene (MoS2/G) heterostructure has been widely used to expand the optical response wavelength of MoS2. To clarify the carrier transfer dynamics in the MoS2/G heterostructure, time-resolved transient absorption and two-color pump–probe measurements are performed. By comparing the carrier dynamics in MoS2 and MoS2/G under different pump wavelengths, we find that interfacial excitons are formed in the heterostructure, and fast hot carriers transfer (<200 fs) from graphene to MoS2 are observed. The results indicate that the formed heterostructure with graphene can not only expand the optical response wavelength of MoS2 but also improve the response time of the device in the near-infrared region.
Vapor-to-glass preparation of biaxially aligned organic semiconductors
Authors: Ju Jianzhu , Chatterjee Debaditya , Voyles Paul M. , Bock Harald , Ediger Mark D.
Published: December 2023

Physical vapor deposition (PVD) provides a route to prepare highly stable and anisotropic organic glasses that are utilized in multi-layer structures such as organic light-emitting devices. While previous work has demonstrated that anisotropic glasses with uniaxial symmetry can be prepared by PVD, here, we prepare biaxially aligned glasses in which molecular orientation has a preferred in-plane direction. With the collective effect of the surface equilibration mechanism and template growth on an aligned substrate, macroscopic biaxial alignment is achieved in depositions as much as 180 K below the clearing point TLC−iso (and 50 K below the glass transition temperature Tg) with single-component disk-like (phenanthroperylene ester) and rod-like (itraconazole) mesogens. The preparation of biaxially aligned organic semiconductors adds a new dimension of structural control for vapor-deposited glasses and may enable polarized emission and in-plane control of charge mobility.
Dynamics of polarization loss and imprint in bilayer ferroelectric tunnel junctions
Authors: Barbot J. , Fontanini R. , Segatto M. , Coignus J. , Triozon F. , Carabasse C. , Bedjaoui M. , Andrieu F. , Esseni D. , Grenouillet L.
Published: December 2023

This paper presents polarization loss and imprint in bilayer ferroelectric tunnel junctions as a function of relaxation time (<1 s) and after different SET/RESET pulses. Measurements were performed on Hf0.5Zr0.5O2/Al2O3 stack at room temperature and systematically compared to reference samples without Al2O3. The experimental results were interpreted using self-consistent simulations coupling the polarization dynamic with charge trapping at the FE/DE interface. From this, mechanisms playing on short-term retention and imprint were explained dynamically. Amount of trapped charge modulated by amplitude and duration of SET/RESET pulses was presented as a root cause.
Effects of heterogeneous nucleation model on computational fluid dynamics simulation of flow boiling heat transfer in the mini-channel
Authors: Chen Yujie , Ji Mingyang , Gao Bo , Wang Bohong , Li Wei , Jiao Kaituo , Sun Dongliang , Yu Bo
Published: December 2023

Bubble nucleation is the initial stage of flow boiling and plays an important role in boiling heat transfer. However, bubble nucleation occurs at a microscopic scale, rendering it challenging for the macroscopic computational fluid dynamics method to realistically simulate this intricate process. In this paper, based on the coupled volume-of-fluid and level set method, a heterogeneous nucleation model is improved and conducted to simulate the subcooled flow boiling in a rectangular mini-channel, considering these conditions both in the presence and absence of a microlayer. The coefficient of the original heterogeneous nucleation model is adjusted across a range from 0.1 to 10.0 times its previous value to establish multiple new nucleation models for illustrating their effects on flow patterns and heat transfer characteristics. For flow boiling without a microlayer, when the coefficient of the original heterogeneous nucleation model is halved, the nucleate boiling intensity upstream of the channel diminishes, resulting in a reduction in the heat transfer coefficient. Nevertheless, this alteration mitigates the formation of slug flow and the appearance of dry patches near the channel outlet, consequently averting a sharp increase in outlet wall superheat. Quantitatively, relative differences of 23.83% and 90.48% in average and local maximum wall superheat are observed, respectively. In contrast, the presence of a very thin microlayer beneath the growing and slipping bubble in flow boiling with a microlayer is notable. This microlayer quickly evaporates, dissipating more than 77% of the input heat flux and substantially expanding the bubble volume. Consequently, under identical wall superheat conditions, the influence of variations in the number of activated bubbles induced by different heterogeneous nucleation models on heat transfer and flow patterns in flow boiling is significantly attenuated. Specifically, when the difference in nucleus site density remains within a tenfold range, the differences in the average and maximum wall superheat are limited to just 16.78% and 33.86%, respectively. Concerning flow boiling in a mini-channel featuring a microlayer, the simulation results verify that large deviations in the activated bubble number have few effects on the flow pattern and wall superheat, greatly reducing heterogeneous nucleation model requirement and promoting the numerical study of flow boiling.
Non-equilibrium molecular dynamics of steady-state fluid transport through a 2D membrane driven by a concentration gradient
Authors: Rankin Daniel J. , Huang David M.
Published: December 2023

We use a novel non-equilibrium algorithm to simulate steady-state fluid transport through a two-dimensional (2D) membrane due to a concentration gradient by molecular dynamics (MD) for the first time. We confirm that, as required by the Onsager reciprocal relations in the linear-response regime, the solution flux obtained using this algorithm agrees with the excess solute flux obtained from an established non-equilibrium MD algorithm for pressure-driven flow. In addition, we show that the concentration-gradient-driven solution flux in this regime is quantified far more efficiently by explicitly applying a transmembrane concentration difference using our algorithm than by applying Onsager reciprocity to pressure-driven flow. The simulated fluid fluxes are captured with reasonable quantitative accuracy by our previously derived continuum theory of concentration-gradient-driven fluid transport through a 2D membrane [D. J. Rankin, L. Bocquet, and D. M. Huang, J. Chem. Phys. 151, 044705 (2019)] for a wide range of solution and membrane parameters, even though the simulated pore sizes are only several times the size of the fluid particles. The simulations deviate from the theory for strong solute–membrane interactions relative to thermal energy, for which the theoretical approximations breakdown. Our findings will be beneficial for a molecular-level understanding of fluid transport driven by concentration gradients through membranes made from 2D materials, which have diverse applications in energy harvesting, molecular separations, and biosensing.
First-principles prediction of the two-dimensional intrinsic ferrovalley material CeX2 (X=F,Cl,Br)
Authors: Li Shujing , Hou Yuefei , Zhou Mei , Zheng Fawei , Shao Xiaohong , Zhang Ping
Published: December 2023

Two-dimensional (2D) ferrovalley semiconductor materials with intrinsic spontaneous valley polarization offer new prospects for valley electronics applications. However, there are only a limited number of known promising candidate materials, which are in urgent need of expansion. In particular, the room-temperature 2D ferrovalley materials are still lacking. In this study, we predicted novel 2D ferromagnetic CeX2 (X=Fe,Cl,Br) monolayers by using first-principles calculations. The monolayer CeX2 is a bipolar magnetic semiconductor with robust dynamical and thermal stabilities, and easy magnetization direction is in the plane. Due to the simultaneous breaking of both inversion symmetry and time-reversal symmetry, the monolayer CeX2 is exhibiting a spontaneous intrinsic valley polarization when magnetized along the out-of-plane z direction. Interestingly, monolayer CeBr2 is a spontaneous intrinsic ferrovalley material with a room temperature of 334 K and an obvious valley splitting of 32 meV. Due to the non-zero valley-contrast Berry curvature, monolayer CeBr2 is a candidate materials for realizing the anomalous valley Hall effect under a suitable applied electric field. Our study provides a theoretical reference for the design of valley electronic devices with anomalous valley Hall effect based on hole-doped CeX2.
On Galilean invariance of mean kinetic helicity
Authors: Soltani Tehrani Dina , Aluie H.
Published: December 2023

While kinetic helicity is not Galilean invariant locally, it is known [Moffatt, J. Fluid Mech. 35, 117 (1969)] that its spatial integral quantifies the degree of knottedness of vorticity field lines. Being a topological property of the flow, mean kinetic helicity is Galilean invariant. Here, we provide a direct mathematical proof that kinetic helicity is Galilean invariant when spatially integrated over regions enclosed by vorticity surfaces, i.e., surfaces of zero vorticity flux. We also discuss so-called relative kinetic helicity, which is Galilean invariant when integrated over any region in the flow.
A review of vertical graphene and its energy storage system applications
Authors: Huang Chaozhu , Mu Yongbiao , Chu Youqi , Gu Huicun , Liao Zifan , Han Meisheng , Zeng Lin
Published: December 2023

The pursuit of advanced materials to meet the escalating demands of energy storage system has led to the emergence of vertical graphene (VG) as a highly promising candidate. With its remarkable strength, stability, and conductivity, VG has gained significant attention for its potential to revolutionize energy storage technologies. This comprehensive review delves deeply into the synthesis methods, structural modifications, and multifaceted applications of VG in the context of lithium–ion batteries, silicon-based lithium batteries, lithium–sulfur batteries, sodium–ion batteries, potassium–ion batteries, aqueous zinc batteries, and supercapacitors. The review elucidates the intricate growth process of VG and underscores the paramount importance of optimizing process parameters to tailor VG for specific applications. Subsequently, the pivotal role of VG in enhancing the performance of various energy storage and conversion systems is exhaustively discussed. Moreover, it delves into structural improvement, performance tuning, and mechanism analysis of VG composite materials in diverse energy storage systems. In summary, this review provides a comprehensive look at VG synthesis, modification, and its wide range of applications in energy storage. It emphasizes the potential of VG in addressing critical challenges and advancing sustainable, high-performance energy storage devices, providing valuable guidance for the development of future technologies.
Finite-temperature properties of PbTiO3 by molecular dynamics simulations
Authors: Wang Jian-Tao , Bu Kun , Hu Fengxia , Wang Jing , Chen Changfeng
Published: December 2023

PbTiO 3 is a prototypical ferroelectric perovskite that is known to undergo a temperature driven ferroelectric tetragonal to paraelectric cubic phase transition, but the understanding of some key phenomena and associated mechanisms underlying this transition remains unclear. Here, using molecular dynamics simulations based on first-principles effective Hamiltonian, we show the behaviors of the phase transition temperature Tc and adiabatic temperature change ΔT of PbTiO3 under an external electric field and tensile stress along the [001] direction. Our results show that the electric field E induces rising Tc via a linear relationTc∝ 0.3083E, rendering the phase transition to go from first-order with thermal hysteresis to second-order without thermal hysteresis above ∼200 kV/cm; meanwhile, a maximum electrocaloric response ΔTmax∼34 K is obtained under E=500 kV/cm. Moreover, external stress (σz) causes rising Tc via a linear relationTc∝160σz and improves the electrocaloric response ΔTmax when combined with the electric field. The present results offer insights into the physical processes and mechanisms that dictate finite-temperature properties of ferroelectric perovskite oxides, laying a foundation for further exploration of this intriguing class of materials.
Lattice Boltzmann simulation of neutrally buoyant circular slip particle motion in a clockwise double-lid-driven square cavity
Authors: Wang Liang , Li Zhitao , Wu Sen , Tao Shi , Zhang Kai , Bi Jingliang , Lu Gui
Published: December 2023

This paper is on the motion of a neutrally buoyant but circular slip particle in a clockwise double-lid-driven square cavity. The slip flow at the particle surface is implemented by the lattice Boltzmann method with corrected slip boundary schemes. The effects of slip length (Ls), initial particle position, Reynolds number (Re), and particle size (D) are studied on the migration of the slip particle. The motion of the circular slip particle is dominated by the centrifugal and boundary-repulsion forces. The results show that the cavity center is the unique fixed point, and once the slip particle initially deviates from the cavity center, it is always stabilized at the same limit cycle. With the increase in slip length, the limit cycle of the circular slip particle is closer to the cavity boundaries, which brings a stronger centrifugal force to balance the increased boundary-confinement effect. As the slip length, Ls, exceeds 0.02D, the limit cycle forms more quickly than the circular no-slip particle. When Re increases to within 1000, the limit cycle is squashed along the leading diagonal of the cavity and pushed toward the boundaries; however, when Re increases beyond 1000, two developing secondary vortices confine the limit cycle to shrink toward the cavity center. With the increase in particle size, the enhanced boundary confinements lead to the shrinkage of the limit cycle toward the cavity center.
Special Topic on High Performance Computing in Chemical Physics
Authors: Straatsma Tjerk P. , Windus Theresa L. , Nakajima Takahito
Published: December 2023

Computational modeling and simulation have become indispensable scientific tools in virtually all areas of chemical, biomolecular, and materials systems research. Computation can provide unique and detailed atomic level information that is difficult or impossible to obtain through analytical theories and experimental investigations. In addition, recent advances in micro-electronics have resulted in computer architectures with unprecedented computational capabilities, from the largest supercomputers to common desktop computers. Combined with the development of new computational domain science methodologies and novel programming models and techniques, this has resulted in modeling and simulation resources capable of providing results at or better than experimental chemical accuracy and for systems in increasingly realistic chemical environments.
Sustainable fabrication of organic electronics
Authors: Trudel Simon
Published: December 2023

Amorphous materials are often an unwanted result of low-temperature thin-film deposition. Yet those disordered materials can be used with great effect for applications with stringent manufacturing requirements.
Predicting the development of Papiamento and Dutch word decoding efficiency in the Dutch Caribbean
Authors: van der Elst-Koeiman Melissa , Segers Eliane , Severing Ronald , Verhoeven Ludo
Published: December 2023

We investigated the development of word decoding (Grades 4–6; 165 children) in Papiamento (L1) and Dutch (L2) in
the postcolonial context of the Dutch Caribbean islands of Aruba, Bonaire, and Curaçao. The results show a steady development over
the upper Grades for both L1 Papiamento and L2 Dutch word decoding in that children became more efficient in word decoding over
the years. However, the children were generally better decoders in L2 Dutch than in L1 Papiamento. Moreover, the initial language
of decoding instruction did not matter for the development of word decoding. The groups were equally efficient in L1 and L2 word
decoding in Grades 4–6. Furthermore, rapid naming and phonological awareness predicted L1 word decoding development, whereas rapid
naming, phonological awareness, and working memory predicted L2 word decoding development. Finally, evidence was found for
linguistic interdependencies for word decoding development from L1 to L2 and vice versa.
Feed additives used during pregnancy in sheep
Authors: Uysal Soner , Tas Seyma
Published: December 2023

Sheep farming constitutes an important part of animal husbandry in underdeveloped and developing countries. In these countries, products obtained from sheep (lamb, meat, milk, wool) constitute the main source of income for breeders with low economic status. Scientific research on ruminant animals mostly focuses on cattle, but studies on sheep are limited. However, with the increasing importance of sheep breeding in recent years, the number of studies in this field has also increased. Lamb and milk yield, which is the main source of income for sheep breeding enterprises, is affected by feeding during pregnancy. Some feed additives used during pregnancy in sheep can support the health of the mother and the offspring, as well as the milk yield in the next lactation. This review is aimed to give extensive information about some substances that are used as feed additives during pregnancy in sheep and to contribute to the literature.
All-Optical Switches for Optical Soliton Interactions in a Birefringent Fiber
Authors: Zhang 张 Xin 鑫 , Yi 伊 Houhui 厚会 , Yao 姚 Yanli 延立 , Wang 王 Shubin 树斌 , Shi 石 Lingxian 领先
Published: December 2023

Interactions among optical solitons can be used to develop photonic information processing devices such as all-optical switches and all-optical logic gates. It is the key to achieve high-speed, high-capacity all-optical networks and optical computers, which is also important in academy. We study the properties of all-optical switches of optical solitons in birefringent fibers, based on the coupled nonlinear Schrödinger equations. It is found that under different initial conditions we can achieve all-optical switching functions. We also study the influence of different physical parameters of birefringent fibers on all-optical soliton switching. The relevant conclusions are conducive to achieving the all-optical switching function of optical solitons in birefringent fibers, providing useful guidance for widespread applications of optical soliton all-optical switches in birefringent fibers of communications.
Phonon Thermal Transport at Interfaces of a Graphene/Vertically Aligned Carbon Nanotubes/Hexagonal Boron Nitride Sandwiched Heterostructure
Authors: Li 李 Menglin 檬璘 , Shakoori Muhammad Asif , Wang 王 Ruipeng 瑞鹏 , Li 李 Haipeng 海鹏
Published: December 2023

Molecular dynamics simulation is used to calculate the interfacial thermal resistance of a graphene/carbon nanotubes/hexagonal boron nitride (Gr/CNTs/hBN) sandwiched heterostructure, in which vertically aligned carbon nanotube (VACNT) arrays are covalently bonded to graphene and hexagonal boron nitride layers. We find that the interfacial thermal resistance (ITR) of the Gr/VACNT/hBN sandwiched heterostructure is one to two orders of magnitude smaller than the ITR of a Gr/hBN van der Waals heterostructure with the same plane size. It is observed that covalent bonding effectively enhances the phonon coupling between Gr and hBN layers, resulting in an increase in the overlap factor of phonon density of states between Gr and hBN, thus reducing the ITR of Gr and hBN. In addition, the chirality, size (diameter and length), and packing density of sandwich-layer VACNTs have an important influence on the ITR of the heterostructure. Under the same CNT diameter and length, the ITR of the sandwiched heterostructure with armchair-shaped VACNTs is higher than that of the sandwiched heterostructure with zigzag-shaped VACNTs due to the different chemical bonding of chiral CNTs with Gr and hBN. When the armchair-shaped CNT diameter increases or the length decreases, the ITR of the sandwiched heterostructure tends to decrease. Moreover, the increase in the VACNT packing density also leads to a continuous decrease in the ITR of the sandwiched heterostructure, attributed to the extremely high intrinsic thermal conductivity of CNTs and the increase of out-of-plane heat transfer channels. This work may be helpful for understanding the mechanism for ITR in multilayer vertical heterostructures, and provides theoretical guidance for a new strategy to regulate the interlayer thermal resistance of heterostructures by optimizing the design of sandwich layer thermal interface materials.
Residue-guided phase unwrapping in fringe projection measurements using second differences
Authors: Fang Meiqi
Published: December 2023

This paper presents an innovative algorithm for unwrapping 2D phase maps with discontinuities. The method employs residue detection for identifying affected areas at a coarse scale. Unlike traditional techniques relying on subjective assessment, this algorithm automates threshold determination, ensuring precision without manual intervention. At the pixel level, it utilizes a bitmap mask based on second differences and the geometric mean formula to locate inconsistencies within the wrapped map precisely. This coarse-to-fine process establishes an optimal threshold for the second difference mask, resulting in highly accurate unwrapped outcomes while maintaining computational efficiency. Compared to conventional methods, this approach delivers superior unwrapped results, making it suitable for diverse applications. Experimental validation includes computer-simulated surfaces and practical fringe projection systems, accompanied by a thorough error analysis.
Dual-porous structured dielectric layer for soft capacitive pressure sensor with high sensitivity
Authors: Shen Jing Jin , Cheng Peng , Zheng Xin , Shan Yi Cai
Published: December 2023

Highly sensitive, soft pressure sensors are urgently required in wearable electronics and robotics applications. In this study, we fabricated a dual-porous structured elastomer using a simple and cost-effective method, in which yeast and sugar particles were introduced into Ecoflex solution. The combination of yeast fermentation and sugar particle dissolution resulted in a dual-porous elastomer consisting of both large closed pores and small open pores. The dual-porous elastomer was employed as the dielectric layer in a soft capacitive pressure sensor. The pressure sensor exhibited a sensitivity over six times higher than that of the sensor with a mono-porous elastomer-based dielectric layer in the pressure range of 1–10 kPa. The finite element simulation demonstrated that the sensitivity enhancement can be attributed to the significantly low stiffness and buckling load resulting from the presence of large closed pores. Finger-attached sensors and motion-monitoring systems demonstrated a wide range of potential applications in wearable electronics.
Preheating in Einstein-Cartan Higgs Inflation: oscillon formation
Authors: Piani Matteo , Rubio Javier
Published: December 2023

We make use of classical lattice simulations in 3+1 dimensions to study the preheating stage of Higgs Inflation in Einstein-Cartan gravity. Focusing for concreteness on a simplified scenario involving the seminal Nieh-Yan term, we demonstrate the formation of dense and spatially localized oscillon configurations constituting up to 70% of the total energy density. The emergence of these meta-stable objects may lead to a prolonged period of matter domination, effectively modifying the post-inflationary history of the Universe as compared to the metric and Palatini counterparts. Notably, the creation of oscillons comes together with a significant gravitational wave signal, whose typical frequency lies, however, beyond the range accessible by existing and planned gravitational wave experiments. The impact of the Standard Model gauge bosons and fermions and the potential extension of our results to more general Einstein-Cartan settings is also discussed.
Photometry, Centroid and Point-spread Function Measurements in the LSST Camera Focal Plane Using Artificial Stars
Authors: Esteves Johnny H. , Utsumi Yousuke , Snyder Adam , Schutt Theo , Broughton Alex , Trbalic Bahrudin , Mau Sidney , Rasmussen Andrew , Plazas Malagón Andrés A. , Bradshaw Andrew , Marshall Stuart , Digel Seth , Chiang James , Rykoff Eli , Waters Chris , Soares-Santos Marcelle , Roodman Aaron
Published: December 2023

The Vera C. Rubin Observatory’s LSST Camera (LSSTCam) pixel response has been characterized using laboratory measurements with a grid of artificial stars. We quantify the contributions to photometry, centroid, point-spread function size, and shape measurement errors due to small anomalies in the LSSTCam CCDs. The main sources of those anomalies are quantum efficiency variations and pixel area variations induced by the amplifier segmentation boundaries and “tree-rings”—circular variations in silicon doping concentration. This laboratory study using artificial stars projected on the sensors shows overall small effects. The residual effects on point-spread function (PSF) size and shape are below 0.1%, meeting the ten-year LSST survey science requirements. However, the CCD mid-line presents distortions that can have a moderate impact on PSF measurements. This feature can be avoided by masking the affected regions. Effects of tree-rings are observed on centroids and PSFs of the artificial stars and the nature of the effect is confirmed by a study of the flat-field response. Nevertheless, further studies of the full-focal plane with stellar data should more completely probe variations and might reveal new features, e.g., wavelength-dependent effects. The results of this study can be used as a guide for the on-sky operation of LSSTCam.
Estimating perceived indoor air quality and environmental satisfaction using a camera
Authors: Du B , Licina D
Published: December 2023

Although indoor environmental monitoring data are increasingly available, they often fail to accurately capture personal environmental perception, comfort, and satisfaction. This disconnection has led to a growing interest in using real-time feedback from building users to improve the control of heating, ventilation, and air-conditioning systems and reduce energy waste. However, traditional questionnaire-based surveys only provide a snapshot at the time of investigation and suffer from a variety of bias sources. To address this, this paper proposes a novel camera-based method for estimating perceived indoor air quality and environmental satisfaction by analysing facial expressions. We conducted indoor air pollution exposure experiments on 24 healthy adults in twin environmental chambers. Their changes in facial expressions were compared between different exposure conditions and the potential correlation between facial expressions and perceived air quality, environmental satisfaction, and self-reported sick building syndrome symptoms was explored. Preliminary results indicate that a common RGB camera can repeatably detect facial expressions from the same subject. Also, results from a subset of five subjects suggest moderate differences in concentration, calmness, contemplation, and tiredness expressions between the two air quality conditions.
Detailed assessment of hybrid ventilation control system in a mixed-mode building in cold climate
Authors: Rabani M , Petersen A J
Published: December 2023

This paper investigates a hybrid ventilation control method for a mixed-mode office landscape in a cold climate, i.e. Norway. The mixed-mode building utilizes a hybrid ventilation system that combines natural ventilation through automatic window opening with a balanced mechanical ventilation system controlled by demand control ventilation (DCV) method. For natural ventilation, the windows consist of two parts: the upper part which is openable and the lower part that is not openable and equipped with external solar shading. From a control point of view, the article elaborates a control algorithm for the proposed hybrid ventilation based on various parameters including outdoor air temperature, indoor air temperature, CO2 level, maximum air change per hour (ACH), operation schedules, and heating/cooling setpoints. The simulation results obtained from the hybrid ventilation and mechanical ventilation cases are compared based on thermal comfort, CO2 level, and energy savings. The primary results show that the proposed hybrid ventilation control method can satisfy the thermal comfort and CO2 level requirements while reducing the energy use for fan and ventilation cooling by approximately 55% and 45%, respectively. While the impact on energy consumption for space and ventilation heating is negligible.
CO2 and thermal comfort analysis of schools in Lugano – a wide-scale monitoring
Authors: Maltese S. , Branca G. , Altieri D. , Boutaleb M. , Pampuri L. , Teruzzi T.
Published: December 2023

Energy consumption and indoor air quality are closely linked, especially in crowded buildings such as schools. This project aims to provide a complete overview of CO2 and temperature levels in the classrooms of primary and pre-schools in the municipality of Lugano. More than 100 classrooms are live-monitored thanks to the sensors installed. The monitoring is still ongoing, and some initial analyses show air quality levels most of the time within admissible ranges, with episodes of overheating. The next phase of the project will be to better assess thermal comfort and to use CO2 and temperature to indirectly assess occupancy, which will be linked to energy consumption.
Thermal comfort and indoor air quality in higher education: A case study in Houston, TX, during mid-season
Authors: Kyropoulou M
Published: December 2023

Providing thermal comfort and good air quality in educational buildings is crucial in enhancing students’ academic performance and productivity. Houston’s typical higher education buildings are designed for 100% mechanically ventilated spaces. But how do such buildings perform when outdoor temperatures are within comfort? This study correlates occupants reported thermal comfort data and gathered empirical thermal comfort and indoor air quality (IAQ) data at a higher education building in Houston, TX, during mid-season, a likely thermally comfortable period. It aims to understand occupants’ thermal sensation and preference and establish correlations between outdoor temperatures, operational temperatures, CO2 levels and occupancy patterns. The results demonstrate different levels of dependence of indoor conditions of the three studied floors on outdoor conditions and occupancy patterns. Such differences are attributed to the large envelope variability among floors of the same use and occupancy and the significant imbalances of the mechanical system settings. The study contributes to a better understanding of the indoor environmental quality of the building, and the author suggests a series of interventions based on the analysis.
Daylighting performance of an innovative Prismatic Vertical Louvers (PVLs) shading system incorporating Prismatic Materials (PMs)
Authors: Haghani M , Place W
Published: December 2023

Daylight has a decisive role in buildings to provide visual comfort, and human health and well-being as well as energy saving potential in buildings; thereby, to benefit from daylighting advantages, it needs to be delivered indoors properly through designing decent daylighting systems. This paper aims to investigate the operational mechanism of an innovative daylighting system, prismatic vertical louvers (PVL), incorporating a microstructure prismatic material (PM), through a comparative study. The PVL shading system continuously rejects the direct radiation of sunlight while it transmits the diffuse scattered skylight resulting in creating a significant potential to improve visual comfort and energy saving in buildings. Through developing a parametric iterative algorithm to simulate the unique optical behavior of the proposed PVL system, the authors evaluated the ability of this innovative system in improving daylight distribution uniformity, and glare occurrence in the space compared to two state-of-the-art shading systems: mesh roller shade (MRS) system, and conventional vertical louvers (CVL). The comparison result of the study reveals the robust capability of the PVL system in enhancing the uniformity distribution of natural light across the work plane as well as removing glare occurrence for occupants.
Enhancing user acceptance in automated systems with human-centric lighting: the role of visual comfort, personality, and preference
Authors: Papinutto M , Colombo M , Boghetti R , Basurto C , Reutter K , Lalanne D , Kämpf J H , Nembrini J
Published: December 2023

Properties of light impact both psychological and physiological aspects. In this context, the effects of light’s correlated colour temperature (CCT) appear less studied than the effects of illuminance, although CCT is known to impact circadian rhythms responsible to maintain day and night cycles. Recently, Human-centric lighting (HCL) proposed to endow electric lighting with daylight dynamic characteristics with recognized benefits on physiological rhythms, particularly in reducing blue light exposure at night. Current lack of studies on the psychological effects of CCT prevents from reaching conclusions regarding the psychological aspects of HCL. The present user experiment aims to shed light on the relationship between HCL and personality, acceptance of an automated system to maximise daylight provision and visual comfort perception of occupants in two different buildings and within two types of offices. In this case, participants selected the HCL paradigm with dynamic CCT more often than a standard fixed CCT design, especially in individual offices. Despite being more frequently set and used to diffuse an appropriate light colour, dynamic CCT was assessed to deliver a heterogeneous light and decreased the overall visual comfort of occupants. Still, dynamic CCT was found to increase the acceptance of the automated system while mediating the relationship between personality and acceptance.