bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved lattice Boltzmann model for moving contact-line with soluble surfactant
Authors: Xu Ting , Bian Xin , Liang Hong
Published: December 2023

Modeling moving contact-line with surfactant has become a widely sought methodology due to its scientific relevance and extensive applications. Within the phase field framework, we present an improved lattice Boltzmann (LB) model for simulating moving contact-line dynamics with soluble surfactant. In this model, a LB equation is used to solve the Navier–Stokes equations, and another two LB equations are utilized to solve the two Cahn–Hilliard-like equations. The modified chemical potentials are incorporated in the LB model by using an equivalent variant of the free energy functional and the corresponding equilibrium distribution functions are also amended. These modifications could circumvent the degraded accuracy of previous LB models in capturing the interfacial behavior and surfactant distribution, and also improve the well-posedness of the LB model. In addition, a dynamic contact angle formulation is introduced to account for the surfactant effect on surface wettability and the resulting contact angle is further implemented in the LB model via a popular geometrical wetting approach. We comprehensively evaluate the numerical performance of the LB model by simulating some benchmark problems. It is found that the LB model achieves a higher accuracy than previous LB models in solving the phase field and surfactant profiles, and also numerical prediction of moving contact-line dynamics with surfactant shows good agreement with the analytical solution. Finally, the LB model is applied to investigate droplet shearing dynamics on solid substrate. The influences of capillary number and solid wetting property on droplet deformation and breakup are analyzed in detail.
Efficient angular dispersed high-order harmonic generation by dual laser pulses interacting with a solid target
Authors: Xia Yili , Li Boyuan , Chen Min , Liu Feng , Yuan Xiaohui , Sheng Zhengming , Zhang Jie
Published: December 2023

High-order harmonics emitted from relativistic laser–solid interaction can be used as a bright extreme ultraviolet source. However, such a source usually has mixed frequencies along the emission direction. Through theoretical and numerical studies, we propose a scheme to realize monochromatic harmonic emission along individual directions by using dual laser pulses with orthogonal polarizations, where a relativistic P-polarized laser is used as a pump laser in combination with a moderate S-polarized laser as a seed laser. We find that harmonics of the S-polarized laser can be efficiently generated with several orders of magnitude enhancement and spontaneous angular dispersion depending on the harmonic order. Our scheme may be beneficial to future applications requiring monochromatic radiation along a specific direction or multi-chromatic radiations in different directions.
Spectral routers for snapshot multispectral imaging
Authors: Catrysse Peter B. , Fan Shanhui
Published: December 2023

Snapshot spectral imaging aims at capturing full spatial and spectral information simultaneously. It can benefit greatly from a photon-efficient spectral decomposition that does not sacrifice spatial resolution. The multispectral filter arrays that enable compact single-chip snapshot multispectral imaging, however, suffer from fundamental and important limitations: low photon efficiency and low spatial resolution. Here, we introduce a spectral router for snapshot multispectral imaging to address these limitations. A spectral router routes all light incident on its entire surface directly to the photodetector of each spectral channel without need for a propagation layer between the router and the detector. Unlike filters, spectral routers do not reject light to achieve spectral selectivity and can ideally exploit 100% of the incident light. Spectral routers also break the size barrier that exists for filter arrays and can be designed with wavelength size footprint. This enables spectral routers to simultaneously provide spectral information as well as spatial information at higher spatial resolution, and can even allow them to provide spectral information without sacrificing spatial information beyond the diffraction limit. We illustrate the concept with two examples. A first spectral router covers the visible range and can achieve ideal optical efficiency for six spectral channels in a sub-micrometer footprint, which is 15 times smaller than a filter array repeat unit with the smallest Fabry–Pérot filters. The second example covers the shortwave infrared (SWIR) range with nine spectral channels and is suitable for pixels that are two times smaller than the smallest SWIR imager pixels demonstrated to date.
α
-In2Se3-based heterojunction photodetector using Nb-doped MoS2
Authors: Lv Xiurui , Liu Guipeng , Zhao Guijuan , Liu Linsheng , Yang Jianhong
Published: December 2023

The built-in electric field at the heterojunction interface can effectively separate electron–hole pairs, which can effectively increase the photocurrent and suppress the dark current. The p–n junction can provide a good depletion layer, so p–n junction photodetectors based on two-dimensional materials are rapidly developing. In this study, Nb-doped MoS2 as a p-type semiconductor and n-type α-In2Se3 were used to form a van der Waals heterojunction photodetector. This photodetector achieves photodetection in the visible to near-infrared range with a responsivity (R) of 87 A/W and a specific detectivity (D*) of 7.5 × 1011 Jones. The carriers introduced by doping make the device less suppressive to dark currents, but maintain a high photoresponsivity. This study adopts doping modulation of the conductive properties for p–n junction photodetectors, and the results are expected to further enhance the photodetection performance.
Tunable nonlinear damping in MoS2 nanoresonator
Authors: Prasad Parmeshwar , Arora Nishta , Naik A. K.
Published: December 2023

Nonlinear damping plays a significant role in several areas of physics, including the dynamics of nanoresonators. However, many aspects remain unclear, and the microscopic source of nonlinear damping is still an active area of research. In particular, the effect of mode coupling on the observed damping has drawn significant interest. Here, we report on the effect of mode coupling on nonlinear damping in a highly tunable MoS2 nano-mechanical drum resonator. In our experiments, we observe enhanced nonlinear damping in the parameter space that favors internal resonance. We observe this enhanced damping both in the direct drive and the parametric drive measurements. The study presents a comprehensive characterization of the tunable nonlinear damping of a MoS2 resonator in a parametric regime. Our work marks a significant advancement in understanding the potential sources of nonlinear damping. Moreover, a highly tunable 2D material based nanoresonator offers an excellent platform to study nonlinear physics and exploit tunable nonlinear damping.
Quantification of face seal leakage using parallel resistance model
Authors: Pushpawela Buddhi , Chea Peter , Ward Ryan , Flagan Richard C.
Published: December 2023

Mask-wearing emerged as the key safety measure to prevent the spreading of COVID-19. In this study, we hypothesized a model to quantify the leakage flow rate through the face mask based on a parallel resistance model. The tests were performed in two ways: (I) mask material test, in which all masks were sealed to a flange to measure transmission through a full mask and prevent leakage around the edges, and (II) mannequin mask test, in which masks were fitted to a mannequin head tightly. For all masks, the pressure drop was measured at eight different flow rates between 5 and 85 LPM, and it was increased linearly with the flow rate (r2 > 0.98). The results of the study showed that the leakage flow rate was 10% of the total flow rate, even for the best-fitted N95 filtering facepiece respirators (FFRs) and KN95 masks. They showed higher resistance to the leaks. The procedure masks and cloth masks showed a leakage flow rate of 25% of the value of the total flow rate, quite a large proportion of the flow. They had lower resistance to leaks.
Molecularly informed field theory for estimating critical micelle concentrations of intrinsically disordered protein surfactants
Authors: Nguyen My. V. T. , Dolph Kate , Delaney Kris T. , Shen Kevin , Sherck Nicholas , Köhler Stephan , Gupta Rohini , Francis Matthew B. , Shell M. Scott , Fredrickson Glenn H.
Published: December 2023

The critical micelle concentration (CMC) is a crucial parameter in understanding the self-assembly behavior of surfactants. In this study, we combine simulation and experiment to demonstrate the predictive capability of molecularly informed field theories in estimating the CMC of biologically based protein surfactants. Our simulation approach combines the relative entropy coarse-graining of small-scale atomistic simulations with large-scale field-theoretic simulations, allowing us to efficiently compute the free energy of micelle formation necessary for the CMC calculation while preserving chemistry-specific information about the underlying surfactant building blocks. We apply this methodology to a unique intrinsically disordered protein platform capable of a wide variety of tailored sequences that enable tunable micelle self-assembly. The computational predictions of the CMC closely match experimental measurements, demonstrating the potential of molecularly informed field theories as a valuable tool to investigate self-assembly in bio-based macromolecules systematically.
Particle dynamics in vertical vibration-driven immersed granular systems: A study with resolved computational fluid dynamics-discrete element method
Authors: Wang Chi , Wei Lubin , An Yi
Published: December 2023

Vibration-driven immersed granular systems (VIGSs) are ubiquitous in nature and industry. However, particle dynamics in 3D VIGSs is hard to obtain directly from experiments. The resolved Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) is introduced to study a cylindrical VIGS subjected to vertical vibration focusing on particle dynamics. A Voronoi-weighted Gaussian interpolation (VWGI) method is used to convert the discrete particle information into a continuous field. The VWGI method enables the estimation of the continuous field for granular systems, especially for those with large-scale non-uniformity and heterogeneity particle distribution in local cells. The results show that the periodic variation of the system's kinetic energy is caused by the collision between the lower particles and the vibrating wall, and the particle kinetic energy decreases with height rising. A velocity spatial structure of convection, moving from the cylinder center to the sidewall, is observed in both immersed and dry systems away from the bottom. Vibration-driven particles can exhibit a similar flow structure to natural convection. Compared to the dry system, the convection strength and momentum transfer in the VIGS are higher, while the momentum diffusion is lower. The fluid restrains the particle energy acquisition and enhances the energy dissipation of the “heated” particles, while the formation of the fluid convection benefits the particle convection directionality. This resolved CFD-DEM study with the VWGI method provides useful results of the particle dynamics in VIGSs, which could provide guidance for some practical applications in minerals processing involving vibration-driven immersed granular systems.
Modified Magnus effect and vortex modes of rotating cylinder due to interaction with free surface in two-phase flow
Authors: Lin Jianfeng , Yao Hua-Dong
Published: December 2023

When employing rotating cylinders as ship anti-rolling devices based on the Magnus effect, the cylinders are near the free surface. However, most of the previous studies on rotating cylinders considered single-phase (SP) flows, where the interaction between the free surface and rotating cylinders was missing. In this study, we explore a rotating cylinder in a two-phase flow using large eddy simulation. Given low submergence depths of less than one cylinder diameter, the pattern of vortices classified as mode A in the SP flow under the same operation conditions is altered to mode E. As regards depths below 1.5 diameters, mode E is changed to mode F′. These modes mentioned above were defined by previous researchers to identify the different wake patterns of rotating cylinders. Increasing the submergence depth in general enhances the lift generation, and this effect is more significant for the rotation with a higher spin ratio of 4 as compared to another spin ratio of 0.5. Nevertheless, the Magnus effect fails when the higher spin ratio is set at a depth of half of the cylinder diameter. As the depth is increased, the drag from the lower spin ratio decays. In contrast, the higher ratio rises significantly up to the depth of two diameters and then drops. This study clarifies the importance of the free surface in affecting the Magus effect. It is also the first time that the mode change of rotating cylinders owing to two-phase flows has been found.
Design of oscillatory dynamics in numerical simulations of compartment-based enzyme systems
Authors: Leathard Anna S. , Beales Paul A. , Taylor Annette F.
Published: December 2023

Enzymatic reactions that yield non-neutral products are known to involve feedback due to the bell-shaped pH-rate curve of the enzyme. Compartmentalizing the reaction has been shown to lead to transport-driven oscillations in theory; however, there have been few reproducible experimental examples. Our objective was to determine how the conditions could be optimized to achieve pH oscillations. We employed numerical simulations to investigate the hydrolysis of ethyl acetate in a confined esterase enzyme system, examining the influence of key factors on its behavior. Specific parameter ranges that lead to bistability and self-sustained pH oscillations and the importance of fast base transport for oscillations in this acid-producing system are highlighted. Suggestions are made to expand the parameter space for the occurrence of oscillations, including modifying the maximum of the enzyme pH-rate curve and increasing the negative feedback rate. This research not only sheds light on the programmable nature of enzyme-driven pH regulation but also furthers knowledge on the optimal design of such feedback systems for experimentalists.
Fractal theory and dynamic contact angle-based imbibition model for two-phase flow in porous media
Authors: Zhang Lei , Imani Gloire , Kang Lixin , Ping Jingjing , Sun Hai , Fan Dongyan , Fu Shuaishi , Hou Lei , Memon Bilal Shams , Yang Yongfei , Yao Jun
Published: December 2023

During the development of tight oil reservoirs, there are significant occurrences of spontaneous imbibition. Understanding the spontaneous imbibition behavior at the core scale of tight sandstone holds significant importance in improving the recovery rate. This study presents a novel mathematical model for characterizing the spontaneous imbibition phenomenon in tight porous media, drawing upon the fractal theory and the dynamic contact angle in capillary bundles. The proposed model has been verified by the results of core imbibition experiments in the literature. Furthermore, we conducted spontaneous imbibition simulation studies using core structures of different pore types extracted from real tight reservoirs to validate the applicability of the new mathematical model. Comparative analysis shows that the derived mathematical approach fits well with the simulation results, but the heterogeneity of the pore space can lead to certain errors between the model and the simulation results. The influencing factors analysis suggests that the higher the porosity, the higher the final recovery rate, whereas an increase in pore fractal dimension has little effect on the final recovery rate.
Heterogeneous nucleation in the random field Ising model
Authors: Yao Liheng , Jack Robert L.
Published: December 2023

We investigate the nucleation dynamics of the three-dimensional random field Ising model under an external field. We use umbrella sampling to compute the free-energy cost of a critical nucleus and use forward flux sampling for the direct estimation of nucleation rates. For moderate to strong disorder, our results indicate that the size of the nucleating cluster is not a good reaction coordinate, contrary to the pure Ising model. We rectify this problem by introducing a coordinate that also accounts for the location of the nucleus. Using the free energy barrier to predict the nucleation rate, we find reasonable agreement, although deviations become stronger as disorder increases. We attribute this effect to cluster shape fluctuations. We also discuss finite-size effects on the nucleation rate.
A guided ion beam investigation of UO2+ thermodynamics and f orbital participation: Reactions of U+ + CO2, UO+ + O2, and UO+ + CO
Authors: Bubas Amanda R. , Zhang Wen-Jing , Armentrout P. B.
Published: December 2023

A guided ion beam tandem mass spectrometer was employed to study the reactions of U+ + CO2, UO+ + O2, and the reverse of the former, UO+ + CO. Reaction cross sections as a function of kinetic energy over about a three order of magnitude range were studied for all systems. The reaction of U+ + CO2 proceeds to form UO+ + CO with an efficiency of 118% ± 24% as well as generating UO2+ + C and UCO+ + O. The reaction of UO+ + O2 forms UO2+ in an exothermic, barrierless process and also results in the collision-induced dissociation of UO+ to yield U+. In the UO+ + CO reaction, the formation of UO2+ in an endothermic process is the dominant reaction, but minor products of UCO+ + O and U+ + (O + CO) are also observed. Analysis of the kinetic energy dependences observed provides the bond energies, D0(U+–O) = 7.98 ± 0.22 and 8.05 ± 0.14 eV, D0(U+–CO) = 0.73 ± 0.13 eV, and D0(OU+–O) = 7.56 ± 0.12 eV. The values obtained for D0(U+–O) and D0(OU+–O) agree well with the previously reported literature values. To our knowledge, this is the first experimental measurement of D0(U+–CO). An analysis of the oxide bond energies shows that participation of 5f orbitals leads to a substantial increase in the thermodynamic stability of UO2+ relative to ThO2+ and especially transition metal dioxide cations.
Performance improvement and noise reduction analysis of multi-blade centrifugal fan imitating long-eared owl wing surface
Authors: Lei Jian , Cui Qin , Qin Guoliang
Published: December 2023

This research was inspired by the long-eared owl's ability to fly silently. For the first time in this study, a wind turbine blade is designed to mimic the wing surface and the leading edge of the long-eared owl. The commonly used two-dimensional blade profile in previous studies is replaced by a more effective three-dimensional profile. This change leads to improved aerodynamic performance of the multi-blade centrifugal fan and reduced noise levels. The airfoil and leading edge profile parameters of the long-eared owl were extracted and utilized. These parameters were used to develop a fitting formula based on their correlation. This formula facilitated the design and optimization of a bionic blade (B-Blade). The results indicate a 4.1% enhancement in the maximum flow rate compared to the original blade fan, alongside a noise reduction of 1.3 dB(A) under identical static pressure conditions. An examination of the internal flow, noise, and sound source characteristics of both fan types was conducted, elucidating the aerodynamic noise mechanism. Fan noise propagation showed pronounced dipole sound source traits. The sound source area at the B-Blade fan's inlet and the volute tongue was more compact, leading to a decrease in mid-low frequency discrete noise. The sound source intensity was also diminished. The B-Blade fan also ameliorated the flow distribution at the impeller outlet, reducing the unstable interaction between the impeller and volute tongue, thereby effectively diminishing noise.
Harnessing non-Watson–Crick’s base pairing to enhance CRISPR effectors cleavage activities and enable gene editing in mammalian cells
Authors: Gao Shuliang , Guan Huiwen , Bloomer Hanan , Wich Douglas , Song Donghui , Khirallah Jennifer , Ye Zhongfeng , Zhao Yu , Chen Mengting , Xu Chutian , Liu Lihan , Xu Qiaobing
Published: December 2023

Genomic DNA of the cyanophage S-2L virus is composed of 2-aminoadenine (Z), thymine (T), guanine (G), and cytosine (C), forming the genetic alphabet ZTGC, which violates Watson–Crick base pairing rules. The Z-base has an extra amino group on the two position that allows the formation of a third hydrogen bond with thymine in DNA strands. Here, we explored and expanded applications of this non-Watson–Crick base pairing in protein expression and gene editing. Both ZTGC-DNA (Z-DNA) and ZUGC-RNA (Z-RNA) produced in vitro show detectable compatibility and can be decoded in mammalian cells, including
Homo sapiens
cells. Z-crRNA can guide CRISPR-effectors SpCas9 and LbCas12a to cleave specific DNA through non-Watson–Crick base pairing and boost cleavage activities compared to A-crRNA. Z-crRNA can also allow for efficient gene and base editing in human cells. Together, our results help pave the way for potential strategies for optimizing DNA or RNA payloads for gene editing therapeutics and give insights to understanding the natural Z-DNA genome.
Measurement of void fraction in gas-water bubbly flow using a derived multi-eigenvalue sequence from normalized EIT impedance matrix
Authors: Suo Peng , Sun Jiangtao , Li Xiaolin , Zhang Xiaokai , Bai Xu , He Feng , Zhang Longci , Xu Lijun
Published: December 2023

Void fraction is one of the dominant parameters of gas-water two-phase flow. Its accurate measurement plays an important role in achieving parameter control and reliable operation in industrial processes. This article proposes a more practical method for the measurement of void fraction in gas-water bubbly flow using a derived multi-eigenvalue sequence from a normalized electrical impedance tomography impedance matrix. The relations between eigenvalues and void fraction, bubble radius, number of bubbles are investigated by numerical simulations, which illustrates the superiority of using multi-eigenvalue rather than the largest eigenvalue for void fraction prediction. The nonlinear mapping between the multi-eigenvalue sequence and void fraction is established by applying the XGBoost model with a sliding window of time series. This proposed method is verified by static and dynamic experiments using a self-developed setup in our laboratory, generating stable gas-water bubbly flow with void fraction of less than 0.12. It is shown that the proposed method can predict void fraction with a relative deviation of 10%. Compared with the conventional method based on the largest eigenvalue, the proposed method efficiently improves the measurement accuracy of void fraction in gas-water bubbly flow and applicability in actual measurement of two-phase flow, which can be further extended to other flow regimes.
Identification of bridge modal parameters from GNSS data by integrating IEWT and robust ICA algorithm
Authors: Yu Jiayong , Xie Yilun , Fang Zhen , Peng Zhihao , Yang Ruitao , Wang Yudong
Published: December 2023

Empirical wavelet transform is often used to process global navigation satellite system (GNSS) bridge deformation monitoring data, but it leads to inaccurate band division and too many spurious modes. To address these problems, this study proposes an improved algorithm to identify bridge modal parameters, which combines improved empirical wavelet transform and robust independent component analysis (ICA). The proposed method adopts the autoregressive power spectrum of an improved covariance algorithm, instead of the Fourier spectrum, for band division. Additionally, it performs noise reduction and reconstruction of multi-channel GNSS monitoring data. The reconstructed signal is inputted as multi-channel observation signal into robust ICA to extract features of the source signal. Finally, the natural excitation technique and Hilbert transform are used to solve the self-oscillation frequency and damping ratio of the structure. The proposed method is validated using both simulation data and the GNSS monitoring data of the Wilford suspension bridge. The results show that the proposed method can effectively reduce the measurement noise and successfully identify the first-order vibration frequencies and damping ratios of bridge. This algorithm can also be applied in the parameter identification of other engineering structures from GNSS data.
Promote lipolysis in white adipocytes by magnetic hyperthermia therapy with Fe3O4 microsphere-doped hydrogel
Authors: Su Yu , Jin Mengshan , Chen Feifei , Xu Chenxiao , Chen Litian , Li Le , Li Yeying , Zhao Mengyuan , Zhu Guanghui , Lin Zhenkun
Published: December 2023

Obesity has become an ongoing global crisis, since it increases the risks of cardiovascular disease, type 2 diabetes, fatty liver, cognitive decline, and some cancers. Adipose tissue is closely associated with the disorder of lipid metabolism. Several efforts have been made toward the modulation of lipid accumulation, but have been hindered by poor efficiency of cellular uptake, low safety, and uncertain effective dosage. Herein, we design an Fe3O4 microsphere-doped composite hydrogel (Fe3O4 microspheres @chitosan/β-glycerophosphate/collagen), termed as Fe3O4@Gel, as the magnetocaloric agent for magnetic hyperthermia therapy (MHT), aiming to promote lipolysis in white adipocytes. The experimental results show that the obtained Fe3O4@Gel displays a series of advantages, such as fast sol–gel transition, high biocompatibility, and excellent magneto-thermal performance. MHT, which is realized by Fe3O4@Gel subjected to an alternating magnetic field, leads to reduced lipid accumulation, lower triglyceride content, and increased mitochondrial activity in white adipocytes. This work shows that Fe3O4@Gel-mediated MHT can effectively promote lipolysis in white adipocytes in vitro, which provides a potential approach to treat obesity and associated metabolic disorders.
Boron-intercalation-triggered crystalline transition of Pd nanosheet assemblies for an enhanced oxygen reduction reaction
Authors: Wang Hongjing , Zhou Tongqing , Xu Shan , Deng Kai , Yu Hongjie , Xu You , Li Xiaonian , Wang Ziqiang , Wang Liang
Published: December 2023

The development of effective and stable cathode electrocatalysts is highly desired for fuel cells. Controlling the composition and morphology of Pd-based materials can provide a great opportunity to improve their oxygen reduction reaction (ORR) performance. Here, we report the synthesis of hexagonal close-packed (hcp) Pd2B nanosheet assemblies (Pd2B NAs) via the boronation reaction between as-synthesized Pd NAs and N,N-dimethylformamide. The hcp Pd2B NAs with uniform pore distribution can provide sufficient active sites for ORRs. The insertion of B atoms can induce the phase transition from face-centered cubic structure to hcp structure, as the most thermodynamically stable phase in the Pd-B alloy, which is beneficial for enhancing the ORR stability and toxicity resistance. Therefore, the hcp Pd2B NAs exhibit superior mass activity, specific activity and excellent stability for ORR. The present strategy of boron-intercalation-triggered crystalline transition of Pd-based nanomaterials is valuable for the design of metal–nonmetal catalysts with enhanced performance.
Self-purification and entanglement revival in lambda matter
Authors: Chen Dongni , Chesi Stefano , Choi Mahn-Soo
Published: December 2023

In this study, we explore the dynamics of entanglement in an ensemble of qutrits with a lambda-type level structure interacting with single-mode bosons. Our investigation focuses on zero-energy states within the subspace of totally symmetric wave functions. Remarkably, we observe a universal two-stage dynamics of entanglement with intriguing revival behavior. The revival of entanglement is a consequence of the self-purification process, where the quantum state relaxes and converges universally to a special dark state within the system.
Catch and release of propagating bosonic field with non-Markovian giant atom
Authors: Xu Luting , Guo Lingzhen
Published: December 2023

The non-Markovianity of physical systems is considered to be a valuable resource that has potential applications to quantum information processing. The control of traveling quantum fields encoded with information (flying qubit) is crucial for quantum networks. In this work, we propose to catch and release the propagating photon/phonon with a non-Markovian giant atom, which is coupled to the environment via multiple coupling points. Based on the Heisenberg equation of motion for the giant atom and field operators, we calculate the time-dependent scattering coefficients from the linear response theory and define the criteria for the non-Markovian giant atom. We analyze and numerically verify that the field bound states due to non-Markovianity can be harnessed to catch and release the propagating bosonic field on demand by tuning the parameters of giant atom.
Fabrication of highly conductive phosphorous-doped nc-SiCx:H thin film on PET
Authors: Liu Jia , Sun Ruirui , Tang Chunjuan , Wang Longgang , Liu Chuanwei , Gao Huaiping , Guo Guanglei , Liu Lina , An Xiuyun , Shan Feng , Sun Hui , Hu Qiubo
Published: December 2023

Plasma enhanced chemical vapor deposition (PECVD) method has been utilized to fabricate phosphorous-doped hydrogenated nanocrystalline silicon carbide (P-doped nc-SiCx:H) thin films on polyethylene terephthalate (PET) substrate. With the aim at obtaining highly conductive thin films, H2/Ar mixed dilution has been applied for creating plasma during deposition, and the variation of structural, electrical and optical properties with H2/Ar flow ratio RH have been systemically investigated through a series of characterizations. Results show that the highly crystallized P-doped nc-SiCx:H thin film can be prepared while the properties are controllable through adjusting RH. In the case of RH = 0.75, the maximum dark conductivity (6.42 S cm−1) and a wide optical bandgap (1.93 eV) are attained. Finally, detail discussion has been made to illustrate the growth mechanism of the flexible P-doped nc-SiCx:H thin films.
Optimisation and numerical analysis of highly efficient CGSe-based thin film solar cell
Authors: Rathod Prashant K , Solanki Pankaj , Kataria Bharat , Markna J H
Published: December 2023

Among the various chalcopyrites compounds used in photovoltaic devices, Copper Gallium Selenium (CGSe) turns out as an underperformer due to its limited photovoltaic performance, So far highest efficiency measured is about 11.9%. This paper investigates the possibilities for efficiency enhancement for the CuGSe layer in Cu2O/CGSe/TiO2/ZnO thin film solar cell structure using the SCAPS-1D simulation program. The short circuit current (Jsc) and power conversion efficiency (PCE) is 30.77 mA cm−2 and 27.10%, with open-circuit voltage (Voc) and fill factor (FF) of 1.03 V and 84.72% respectively. Furthermore, we evaluated some specific parameters of TiO2/CGSe heterostructure, such as the influence of layer thickness, operating temperature, the effect of defect density and acceptor density of CGSe layer, metal work function, and the effect of series and shunt resistance on cell performance. We investigated that combining TiO2 as an ETL and Cu2O as HTL with a CGSe absorber layer is novel and promising, which results in higher power conversation efficiency and improves other PV parameters. The application of CGSe/TiO2 heterojunction in a simulated model offers a viable method for the development of high-efficiency solar cell devices.
Quantum conditional mutual information of W state in non-inertial frames
Authors: Saveetha H , Rohde Peter P , Chandrashekar R
Published: December 2023

Quantum conditional mutual information (QCMI) is a versatile information theoretic measure. It is used to find the amount of correlations between two qubits from the perspective of a third qubit. In this work, we characterise the QCMI of tripartite W-states when some of the qubits are in accelerated motion. Here for our investigations we consider a massless fermionic field in the single-mode approximation. We consider all possible situations with respect to the acceleration of the qubits. From our results, we observe that QCMI can either increase or decrease depending on the role of the qubit being accelerated. Finally we discuss the connection between QCMI and correlations by studying the biseparable and separable states.
Study of energy transfer process and radiative properties of CaAl4O7:Ho3+ phosphor for green light emission
Authors: Singh Vijay , Seshadri M , Saravanakumar S , Joo Ji Bong
Published: December 2023

This work comprehensively analyse the structural and photoluminescence properties of Ho3+-doped CaAl4O7 phosphor systems. X-ray diffraction (XRD), diffuse reflectance spectrum (DRS), photoluminescence (PL), and Fourier transform infrared (FT-IR) spectroscopy measurements were carried out, and Rietveld analysis confirmed the pure monoclinic structure of CaAl4O7:Ho3+ phosphor. The FT-IR spectrum showed absorption bands for the tetrahedral sites of the Al-O bonds and the octahedral sites of the Ca-O bonds, which indicate the formation of the CaAl4O7:Ho3+ phosphor. The diffuse reflectance spectrum shows sharp peaks in the visible and near-infrared regions. Photoluminescence excitation (PLE) measurements were performed on all the phosphor samples by monitoring emissions at 545 nm. Radiative properties such as total radiative transition probabilities (AT), radiative lifetime (τ
rad), and branching ratios (β) are reported by Judd–Ofelt analysis and PLE spectral measurements. Upon 454 nm excitation, a green emission band is observed at around 545 nm (5F4 + 5S2 → 5I8), and these results indicate that x = 0.05 mol Ho3+ is the optimum concentration as the 5F4 + 5S2 → 5I8 emission intensity reaches its maximum. The emission intensity quenching and energy transfer mechanism are discussed, and the results suggest that the CaAl4O7:Ho3+ samples are suitable for green-emitting phosphor.
Study of sedimentation characteristics of an elliptical squirmer in a vertical channel
Authors: Ying Yuxiang , Jiang Tongxiao , Li Siwen , Nie Deming , Lin Jianzhong
Published: December 2023

We used a two-dimensional lattice Boltzmann method to simulate the sedimentation motion of an elliptical squirmer in a vertical channel, taking into account the case of a circular squirmer, aiming to more realistically simulate the swimming of microorganisms in nature. The study in this was divided into two phases. The first phase comprised the numerical calculations of an elliptical squirmer with an aspect ratio of c = 2.0 and revealed three typical motion modes: steady inclined motion, wall-attraction oscillation, and large-amplitude oscillation. It was found that the formation of these three motion modes and transitions between modes are related to the pressure distribution formed between the elliptical squirmer and wall. In addition, significant differences exist between the motions of elliptical and circular squirmers. The force generated by the interaction between the elliptical squirmer and wall does not all point towards its center of mass, resulting in an additional torque on the elliptical squirmer; this is not the situation for the circular squirmer. The second phase of the study simulated squirmers with different aspect ratios (c = 1.0, c = 3.0). It was found that for an elliptical squirmer with an aspect ratio c = 3.0, the large-amplitude oscillation mode (among the above three motion modes) no longer exists. By combining the motion modes of a circular squirmer in the channel, it can be observed that as the aspect ratio c increases, the squirmer’s head direction tends to be more vertical, which may reduce the drag force during swimming.
Enhanced measurement precision with continuous interrogation during dynamical decoupling
Authors: Zhang 张 Jun 军 , Du 杜 Peng 鹏 , Jing 敬 Lei 雷 , Xu 徐 Peng 鹏 , You 尤 Li 力 , Zhang 张 Wenxian 文献
Published: December 2023

Dynamical decoupling (DD) is normally ineffective when applied to DC measurement. In its straightforward implementation, DD nulls out DC signal as well while suppressing noise. This work proposes a phase relay method that is capable of continuously interrogating the DC signal over many DD cycles. We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose–Einstein condensate. Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 atoms, respectively, while ambient laboratory level noise is suppressed by DD. Our work offers a practical approach to mitigate the limitations of DD to DC measurement and would find other applications for resorting coherence in quantum sensing and quantum information processing research.
Prediction of river salinity with artificial neural networks
Authors: Kulisz M , Kujawska J , Aubakirova Z , Wojtas E
Published: December 2023

This paper presents the development and evaluation of an Artificial Neural Network (ANN) based on the model for predicting the salinity of the Warta River. The study focused on the prediction of river water salinity, expressed in terms of electrical conductivity (EC), using the proposed ANN structure of 7-10-1. The network showed a satisfactory ability to capture the interrelationships between the input data: sulphates, chlorides, calcium, magnesium, total hardness, pH, and total dissolved solids. The correlation coefficient (R) values for the training, validation and test sets were 0.99444, 0.96988 and 0.97174, respectively. From the results, it can be concluded that the developed model is suitable for predicting the EC of the river.
Analysis of the impact of trailing-edge wing flaps on the aerodynamic characteristics and performance of the Tecnam P-2008JC aircraft
Authors: Kopeć I , Kawałko M
Published: December 2023

The aim of the article was to analyse the impact of three selected types of trailing-edge flaps on the aerodynamic characteristics and performance of the Tecnam P-2008JC aircraft. The SOLIDWORKS software, together with the Flow Simulation module, was used to design the 3D model of the aircraft and to simulate the air flow. The article contains descriptions of issues related to the aerodynamics and dynamics of aircraft motion, calculations describing the procedure for designing and building a model of the tested aircraft in the SOLIDWORKS software, performing simulations using the Flow Simulation module and determining the aerodynamic characteristics of the aircraft with the flaps applied, determining the basic performance of the aircraft with extended flaps, and then comparing the determined performance with the in a configuration without flaps.
Comparative analysis of stiffness measurement methods for lamination stacks in electric machines
Authors: Szabó Viktor , Gábor Gazdagh Zoltán , Vehovszky Balázs
Published: December 2023

With the increasingly strict global regulations on vehicle emissions, the demand for electromobility has risen due to its potential to reduce local emissions. However, designing an electric motor for use in passenger cars poses significant challenges. The e-motor should operate reliably in various climates with good mechanical and electrical characteristics, be lightweight, withstand repetitive thermal and structural loads, be cost-effective, and - last but not least - exhibit good noise and vibration properties. To meet these requirements, virtual testing through simulations has become the most efficient and economical approach, enabling the identification of weaknesses and unwanted behaviors before physical prototyping. This paper focuses on the testing of lamination stacks, a critical component of electric motors. Two methods of stiffness measurement for such parts are compared: static stiffness determination and dynamic analysis. The former involve compressing the specimen and measuring the force-displacement response, while dynamic method uses the restoring force surface method to obtain the stiffness and damping characteristics. The study highlights the importance of considering nonlinearity in stiffness measurements. The stiffness of lamination stacks varies depending on the pretension state, and a significant hysteresis exists between the loading and unloading curves. The paper discusses the experimental procedures for each method. The findings emphasize the necessity of accurate stiffness characterization for different applications, such as structural strength, modal analysis, dynamic analysis, and noise-vibration-harshness (NVH) studies. The research contributes to the development of electric machines by providing insights into effective stiffness measurement techniques for lamination stacks.
Surface Deformation Assessment due to the Grindulu Fault Activities using Sentinel 1 Data by Applying the Small Baseline Subset (SBAS)-InSAR Technique
Authors: Anjasmara Ira Mutiara , Timur Annisa Rahmawati , Agustin Fitriani
Published: December 2023

The location of Grindulu Fault is in the Pacitan Regency on the Southern Coast of Java, which directly faces the South Java Subduction zone. The activities of the fault could contribute to the surface deformation in the surrounding area. The Meteorology Climatology and Geophysics Council in Indonesia (BMKG) reported a 3.1 Mw earthquake on 7 November 2019, possibly related to the Grindulu fault activities. In this research, we assess the surface deformation around the Grindulu Fault using the Sentinel I data by applying the Small Baseline Subset (SBAS) - Interferometry Synthetic Aperture Radar (InSAR) technique. The SBAS-InSAR is one of the techniques that can provide spatial-temporal continuous analysis of the surface deformation over the extent of InSAR data. The SBAS algorithm was applied to twenty-three (23) ascending Sentinel-1B images to assess the surface deformation in Pacitan between 2019 and 2021 using the GMTSAR software. The results showed surface deformation dominated by subsidence over the whole area, except at the northern part of Grindulu Fault, with the mean velocity values ranging from -2.07 to -43.05 mm/yr.
Combined a Pressure Sensor and Internet of Things in a Low-Cost Tide Gauge
Authors: Pratomo Danar Guruh , Syah Muhammad Ardian
Published: December 2023

Tides are important in many fields, such as port planning, nautical charting, and bathymetry surveys. However, the distribution of tide observation stations in Indonesia is still uneven, so simple tidal data collection still uses tide palms to observe the movement of sea levels. The manual tidal observation method has limitations because visually the ability of the observer to see the tide reading is different, so it is subjective. Therefore, the solution to this problem is a tidal instrument that is easy to make, provides real-time data, and produces accurate information, saving energy and time. However, using automatic tide gauge instruments is still not affordable in the Indonesian market. This study creates a low-cost pressure tide gauge by integrating a pressure sensor with an Arduino microcontroller. In addition, the data monitoring process uses the Internet of Things system. Data from the instrument measurements were uploaded to the Thingspeak website live, allowing observers to monitor in real time. Instrument’s data with noise and anomalies will go through a data filtering process with the moving average and moving median methods. Testing the instrument’s error rate compares the data generated by the instrument with tidal data from the Indonesian Geospatial Agency (BIG). Both tidal data went through calculating Root Mean Square Error, or RMSE. Based on the instrument error test results, the RMSE value for moving average data against BIG is 27.963 cm and moving median data against BIG is 27.787 cm.
Parametric optimisation of a dual cantilever flutter for electromagnetic wind energy harvesting
Authors: Velusamy V R , Foong F M , Nik Mohd N A R , Thein C K
Published: December 2023

This paper investigates the parametric optimisation of dual cantilever flutter (DCF) beams for electromagnetic wind energy harvesting application. When two cantilever beams are placed side by side facing the direction of the wind flow, both beams would oscillate in an anti-phase motion once the critical flutter speed has been achieved. This arrangement is known as the DCF and it represents an ideal situation for energy harvesting through electromagnetic induction due to its anti-phase motion. Experimental results showed that the optimum load resistance value for the device is equivalent to a single-degree-of-freedom vibration energy harvester for low electromagnetic coupling case, despite the difference in the type of oscillations. Further analysis showed that there among the two possible arrangements for the magnets one arrangement results in a 51.5% larger magnetic flux density. It was seen that reducing the length of the electromagnetic DCF by 41.2% can increase the power output of the device by approximately six times, although the critical flutter speed also increased by 125.0%. Finally, some suggestions were provided on how to further improve the device.
The ‘wild boar paradox’ of radioactive meat solved
Authors: Harris Margaret
Published: December 2023

A team of chemists and radiation experts in Germany and Austria have come up with an explanation for why radiation levels in wild boar have remained constant for the past 30 years, even though levels ought to be falling.
Magnetic attraction
Authors: McKenzie James
Published: December 2023

James McKenzie explains why magnetism is so important for physics-based businesses.
Beyond the bomb
Authors: Glester Andrew , Durrani Matin , Dacey James , Johnston Hamish , Banks Michael , Gardner Kate
Published: December 2023

Andrew Glester reviews the film Oppenheimer, written and directed by Christopher Nolan.
Aerosol and surface contamination assessment of a novel ventilated infectious aerosol containment device
Authors: Fang Runcheng , Andrus Niles , Dominguez Thomas , Sleeth Darrah K , Jones Rachael M
Published: December 2023

Healthcare personnels (HCPs) are at risk of respiratory infectious diseases during patient care activities. HCPs rely primarily on personal protective equipment to prevent pathogen exposures, but there is a need to develop alternative, or complementary control strategies, including engineering controls. The objective of this study was to evaluate the ability of the 3 designs (denoted D1A, D1B, and D2) of the University of Utah Containment Ventilation for Exposure Reduction (U-COVER), a protective barrier enclosure device to contain respirable aerosols when placed over a simulated patient. The 2 primary performance metrics were the percent reduction in: (i) the concentration of respirable aerosols in the simulated breathing zone of an HCP, and (ii) surface contamination outside the device, which were tested using salt aerosols and fluorescein aerosols, respectively. Briefly, salt or fluorescein aerosols were generated as though expelled by a prone patient under 3 conditions: (i) no device (control), (ii) with the device but without exhaust ventilation, and (iii) with the device with exhaust ventilation. Device D2 was also tested under simulated use conditions, in which cardboard “arms” were placed inside the device ports. All 3 device designs showed the ability to reduce particle concentrations in the simulated HCP breathing zone and on surfaces by >99% with exhaust ventilation compared to the control condition. Without exhaust ventilation, device performance was lower and highly variable. Under simulated use conditions, device D2 reduced particle concentrations in the simulated HCP breathing zone by ≥91% and on surfaces by >99% relative to control for all combinations of “arms” tested. The U-COVER device demonstrates excellent aerosol containment and warrants further testing with dynamic simulated or actual use conditions.