Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (51)

Search Parameters:
Keywords = dual-phase lag

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
21 pages, 6227 KiB  
Article
A One-Phase Injection Method with Dual Inhibition for Improving the Strength and Uniformity of MICP
by Yanni Huang, Fengyin Liu and Xiangtong Zhang
Materials 2025, 18(11), 2514; https://doi.org/10.3390/ma18112514 - 27 May 2025
Viewed by 395
Abstract
The formation and spatial uniformity of calcium carbonate (CaCO3) are critical for evaluating the effectiveness of microbial-induced calcium carbonate precipitation (MICP) in geotechnical applications. In recent years, the single-phase injection method has emerged as a promising alternative to traditional two-phase processes [...] Read more.
The formation and spatial uniformity of calcium carbonate (CaCO3) are critical for evaluating the effectiveness of microbial-induced calcium carbonate precipitation (MICP) in geotechnical applications. In recent years, the single-phase injection method has emerged as a promising alternative to traditional two-phase processes by addressing the issue of uneven CaCO3 distribution. This study proposes a dual inhibition strategy that delays the mineralization reaction by synergistically lowering pH and temperature, thereby promoting uniform precipitation and enhanced compressive strength in cemented sand columns. A series of experiments, including bacterial growth, aqueous reaction, sand column reinforcement, and microstructural characterization, were conducted. Results show that the minimum pH required for flocculation increases from ~4.5 at 40 °C to ~6.0 at 10 °C. Under dual inhibition, the lag period effectively improved the spatial uniformity of CaCO3 and enabled complete calcium utilization within 24 h. After four treatment cycles, the CaCO3 content at 10 °C increased by 53%, and the unconfined compressive strength reached 2.5 MPa, a 50% improvement over the 40 °C condition. XRD analysis confirmed that calcite was the dominant phase (85–90%), accompanied by minor vaterite. These findings demonstrate the adaptability and efficiency of the dual inhibition method across temperature ranges, providing a cost-effective solution for broader engineering applications. Full article
(This article belongs to the Section Biomaterials)
Show Figures

Figure 1

18 pages, 1781 KiB  
Article
Multi-Scale Analysis Based on Wavelet Transform of Reservoir and River Total Phosphorus Correlation and Determination of Monitoring Time Scales
by Zewen Liu, Jihong Xia, Mengshi Li, Roland Bol, Qiqi Wang, Yue Wang, Jiayi Zu, Qihua Wang, Shuyi Ji and Hongli Zhan
Water 2025, 17(5), 712; https://doi.org/10.3390/w17050712 - 28 Feb 2025
Viewed by 664
Abstract
Total phosphorus (TP) dynamics between reservoirs and inflowing rivers critically affect eutrophication risks, but their multi-scale interactions remain insufficiently quantified. This study applied wavelet transform analysis to 8-year TP time series data from the Shanxi Reservoir and its inflowing rivers. Key findings include [...] Read more.
Total phosphorus (TP) dynamics between reservoirs and inflowing rivers critically affect eutrophication risks, but their multi-scale interactions remain insufficiently quantified. This study applied wavelet transform analysis to 8-year TP time series data from the Shanxi Reservoir and its inflowing rivers. Key findings include the following: (1) Morlet wavelet decomposition revealed dominant 8–16-month cycles for reservoir TP, contrasting with 4–8-month cycles in river TP; (2) wavelet coherence analysis identified a 90° phase lag (2–4 months delay) between reservoir and river TP at the 8–16-month scale; and (3) the time–frequency localization capability quantified rapid responses—reservoir TP reacted within 2 months to abrupt river TP increases, showing stronger intensity. Multi-resolution analysis further distinguished the driving mechanisms: interannual cycles (>12 months) governed reservoir TP variations, while seasonal cycles (<8 months) controlled river TP fluctuations. The study demonstrated wavelet analysis’ dual strengths: resolving scale-specific interactions through multi-scale decomposition and quantifying transient responses via phase coherence metrics. The 90° phase shift exposes hysteresis in TP transport, and the 2-month response threshold defines critical intervention timing. An adaptive monitoring framework is proposed as follows: ≤8-month sampling under stable conditions and 2-month intervals during TP surges, providing a time–frequency decision tool for precise reservoir water quality management. Full article
Show Figures

Figure 1

23 pages, 3190 KiB  
Article
Numerical Solution of Mathematical Model of Heat Conduction in Multi-Layered Nanoscale Solids
by Aníbal Coronel, Ian Hess, Fernando Huancas and José Chiroque
Axioms 2025, 14(2), 105; https://doi.org/10.3390/axioms14020105 - 30 Jan 2025
Viewed by 657
Abstract
In this article, we are interested in studying and analyzing the heat conduction phenomenon in a multi-layered solid. We consider the physical assumptions that the dual-phase-lag model governs the heat flow on each solid layer. We introduce a one-dimensional mathematical model given by [...] Read more.
In this article, we are interested in studying and analyzing the heat conduction phenomenon in a multi-layered solid. We consider the physical assumptions that the dual-phase-lag model governs the heat flow on each solid layer. We introduce a one-dimensional mathematical model given by an initial interface-boundary value problem, where the unknown is the solid temperature. More precisely, the mathematical model is described by the following four features: the model equation is given by a dual-phase-lag equation at the inside each layer, an initial condition for temperature and the temporal derivative of the temperature, heat flux boundary conditions, and the interfacial condition for the temperature and heat flux conditions between the layers. We discretize the mathematical model by a finite difference scheme. The numerical approach has similar features to the continuous model: it is considered to be the accuracy of the dual-phase-lag model on the inside each layer, the initial conditions are discretized by the average of the temperature on each discrete interval, the inside of each layer approximation is extended to the interfaces by using the behavior of the continuous interface conditions, and the inside each layer approximation on the boundary layers is extended to state the numerical boundary conditions. We prove that the finite difference scheme is unconditionally stable and unconditionally convergent. In addition, we provide some numerical examples. Full article
(This article belongs to the Special Issue Mathematical Methods in the Applied Sciences, 2nd Edition)
Show Figures

Figure 1

24 pages, 1088 KiB  
Article
Multi-Dimensional Double Deep Dynamic Q-Network with Aligned Q-Fusion for Dual-Ring Barrier Traffic Signal Control
by Qiming Zheng, Hongfeng Xu, Jingyun Chen and Kun Zhang
Appl. Sci. 2025, 15(3), 1118; https://doi.org/10.3390/app15031118 - 23 Jan 2025
Cited by 1 | Viewed by 845
Abstract
Model-free deep reinforcement learning (MFDRL) is well-suited for real-time traffic signal control (RTSC), as it is a sequential decision problem where the environment is difficult to be a priori modeled, but has performance metrics sufficing as rewards. Previous studies have not ideally employed [...] Read more.
Model-free deep reinforcement learning (MFDRL) is well-suited for real-time traffic signal control (RTSC), as it is a sequential decision problem where the environment is difficult to be a priori modeled, but has performance metrics sufficing as rewards. Previous studies have not ideally employed MFDRL systems at typical intersections with a dual-ring barrier phase structure (DRBPS) and second-by-second signal operation. DRBPS allows phases to time flexibly while satisfying signal timing constraints in engineering, making it complicated yet common in real-world applications. This study proposes an MFDRL method, termed MD4-AQF, to address the RTSC problem under DRBPS. The state can be represented as a 4 × 30 × 4 × 4 array. We define action based on “decision point aligning” to produce a consistent action space that controls dual-ring concurrent phases simultaneously. We developed a training algorithm based on a “multi-dimensional Q-network” that reduces the number of learnable actions from 600+ to 52. We designed action selection based on “aligned Q-fusion” to end two lagging phases simultaneously with a shared compromise sub-action. In simulation experiments, MD4-AQF trains an agent to improve average vehicle delay from 135 s to 48 s. It surpasses another MFDRL ablated method by 14%, and a fully actuated conventional method by 19%. Full article
(This article belongs to the Section Transportation and Future Mobility)
Show Figures

Figure 1

15 pages, 582 KiB  
Article
Neuromodulation Effect According to Lesion Location After Dual-Mode Brain Stimulation in Patients with Subacute Stroke: A Preliminary Study
by Minji Lee, Wanjoo Park, Eunhee Park, Soon-Jae Kweon and Yun-Hee Kim
Appl. Sci. 2024, 14(21), 9636; https://doi.org/10.3390/app14219636 - 22 Oct 2024
Viewed by 1297
Abstract
Dual-mode non-invasive brain stimulation using repetitive transcranial magnetic stimulation and transcranial direct current stimulation is known to help neurorehabilitation in patients with stroke. However, this neuromodulation effect may vary depending on the lesion location of patients with stroke, and the basis in lesion [...] Read more.
Dual-mode non-invasive brain stimulation using repetitive transcranial magnetic stimulation and transcranial direct current stimulation is known to help neurorehabilitation in patients with stroke. However, this neuromodulation effect may vary depending on the lesion location of patients with stroke, and the basis in lesion location for this is insufficient. This study aims to investigate the difference in neuromodulation effectiveness according to the lesion location after dual-mode brain stimulation using electroencephalography signals. Eight patients with ischemic subacute stroke and 11 healthy controls participated in this study. Brain stimulation was conducted in one session per day for a total of 10 days over the motor cortex, electroencephalography was measured for 5 min with eyes closed, and motor function was evaluated before and after dual-mode stimulation. The lesion location was divided into an infratentorial stroke (ITS) and a supratentorial stroke (STS) based on tentorium cerebelli. In addition, we focused on the mu and beta bands related to motor function. In terms of intrahemispheric connectivity, the mu weighted phase lag index over the contralesional primary motor cortex was significantly higher in only ITS before stimulation compared to healthy controls, and mu Granger causality over the ipsilesional primary motor cortex was significantly higher in both ITS and STS after stimulation compared to healthy controls. In contrast, from the perspective of interhemispheric connectivity, the laterality of beta Granger causality before stimulation in ITS was lower than that of healthy controls and significantly increased after stimulation. The effect of brain stimulation may vary depending on the lesion location of patients with stroke, and these findings provide indicative insights into effective dual-mode stimulation interventions for neurorehabilitation. Full article
(This article belongs to the Special Issue New Insights into Neurorehabilitation)
Show Figures

Figure 1

20 pages, 850 KiB  
Article
Let It Snow: Intercomparison of Various Total and Snow Precipitation Data over the Tibetan Plateau
by Christine Kolbe, Boris Thies and Jörg Bendix
Atmosphere 2024, 15(9), 1076; https://doi.org/10.3390/atmos15091076 - 5 Sep 2024
Viewed by 1274
Abstract
The Global Precipitation Measurement Mission (GPM) improved spaceborne precipitation data. The GPM dual-frequency precipitation radar (DPR) provides information on total precipitation (TP), snowfall precipitation (SF) and snowfall flags (surface snowfall flag (SSF) and phase near surface (PNS)), among other variables. Especially snowfall data [...] Read more.
The Global Precipitation Measurement Mission (GPM) improved spaceborne precipitation data. The GPM dual-frequency precipitation radar (DPR) provides information on total precipitation (TP), snowfall precipitation (SF) and snowfall flags (surface snowfall flag (SSF) and phase near surface (PNS)), among other variables. Especially snowfall data were hardly validated. This study compares GPM DPR TP, SF and snowfall flags on the Tibetan Plateau (TiP) against TP and SF from six well-known model-based data sets used as ground truth: ERA 5, ERA 5 land, ERA Interim, MERRA 2, JRA 55 and HAR V2. The reanalysis data were checked for consistency. The results show overall high agreement in the cross-correlation with each other. The reanalysis data were compared to the GPM DPR snowfall flags, TP and SF. The intercomparison performs poorly for the GPM DPR snowfall flags (HSS = 0.06 for TP, HSS = 0.23 for SF), TP (HSS = 0.13) and SF (HSS = 0.31). Some studies proved temporal or spatial mismatches between spaceborne measurements and other data. We tested whether increasing the time lag of the reanalysis data (+/−three hours) or including the GPM DPR neighbor pixels (3 × 3 pixel window) improves the results. The intercomparison with the GPM DPR snowfall flags using the temporal adjustment improved the results significantly (HSS = 0.21 for TP, HSS = 0.41 for SF), whereas the spatial adjustment resulted only in small improvements (HSS = 0.12 for TP, HSS = 0.29 for SF). The intercomparison of the GPM DPR TP and SF was improved by temporal (HSS = 0.3 for TP, HSS = 0.48 for SF) and spatial adjustment (HSS = 0.35 for TP, HSS = 0.59 for SF). Full article
(This article belongs to the Section Meteorology)
Show Figures

Figure 1

16 pages, 5066 KiB  
Article
Analysis of a Rainstorm Process in Nanjing Based on Multi-Source Observational Data and Lagrangian Method
by Yuqing Mao, Youshan Jiang, Cong Li, Yi Shi and Daili Qian
Atmosphere 2024, 15(8), 904; https://doi.org/10.3390/atmos15080904 - 29 Jul 2024
Viewed by 1187
Abstract
Using multi-source observation data including automatic stations, radar, satellite, new detection equipment, and the Fifth Generation European Centre for Medium-Range Weather Forecasts Reanalysis (ERA-5) data, along with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) platform, an analysis was conducted on a rainstorm process [...] Read more.
Using multi-source observation data including automatic stations, radar, satellite, new detection equipment, and the Fifth Generation European Centre for Medium-Range Weather Forecasts Reanalysis (ERA-5) data, along with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) platform, an analysis was conducted on a rainstorm process that occurred in Nanjing on 15 June 2020, with the aim of providing reference for future urban flood control planning and heavy rainfall forecasting and early warning. The results showed that this rainstorm process was generated under the background of an eastward-moving northeast cold vortex and a southward retreat of the Western Pacific Subtropical High. Intense precipitation occurred near the region of large top brightness temperature (TBB) gradient values or the center of low TBB values on the northern side of the convective cloud cluster. During the heavy precipitation period, the differential propagation phase shift rate (KDP), differential reflectivity factor (ZDR), and zero-lag correlation coefficient (ρHV) detected by the S-band dual-polarization radar all increased significantly. The vertical structure of the wind field detected by the wind profile radar provided a good indication of changes in precipitation intensity, showing a strong correspondence between the timing of maximum precipitation and the intrusion of upper-level cold air. The abrupt increase in the integrated liquid water content observed by the microwave radiometer can serve as an important indicator of the onset of stronger precipitation. During the Meiyu season in Nanjing, convective precipitation was mainly composed of small to medium raindrops with diameters less than 3 mm, with falling velocities of raindrops mainly clustering between 2 and 6 m·s−1. The rainstorm process featured four water vapor transport channels: the mid-latitude westerly channel, the Indian Ocean channel, the South China Sea channel, and the Pacific Ocean channel. During heavy rainfall, the Pacific Ocean water vapor channel was the main channel at the middle and lower levels, while the South China Sea water vapor channel was the main channel at the upper level, both accounting for a trajectory proportion of 34.2%. Full article
Show Figures

Figure 1

14 pages, 6211 KiB  
Article
Evaluating the Safety of Bacillus cereus GW-01 Obtained from Sheep Rumen Chyme
by Bowen Xu, Xinyi Huang, Haixiong Qin, Ying Lei, Sijia Zhao, Shan Liu, Gang Liu and Jiayuan Zhao
Microorganisms 2024, 12(7), 1457; https://doi.org/10.3390/microorganisms12071457 - 18 Jul 2024
Cited by 1 | Viewed by 1536
Abstract
Bacillus cereus is responsible for 1.4–12% food poisoning outbreaks worldwide. The safety concerns associated with the applications of B. cereus in health and medicine have been controversial due to its dual role as a pathogen for foodborne diseases and a probiotic in humans [...] Read more.
Bacillus cereus is responsible for 1.4–12% food poisoning outbreaks worldwide. The safety concerns associated with the applications of B. cereus in health and medicine have been controversial due to its dual role as a pathogen for foodborne diseases and a probiotic in humans and animals. In this study, the pathogenicity of B. cereus GW-01 was assessed by comparative genomic, and transcriptome analysis. Phylogenetic analysis based on a single-copy gene showed clustering of the strain GW-01, and 54 B. cereus strains from the NCBI were classified into six major groups (I–VI), which were then associated with the source region and sequence types (STs). Transcriptome results indicated that the expression of most genes related with toxins secretion in GW-01 was downregulated compared to that in the lag phase. Overall, these findings suggest that GW-01 is not directly associated with pathogenic Bacillus cereus and highlight an insightful strategy for assessing the safety of novel B. cereus strains. Full article
(This article belongs to the Section Veterinary Microbiology)
Show Figures

Figure 1

21 pages, 511 KiB  
Article
A Semi-Explicit Algorithm for Parameters Estimation in a Time-Fractional Dual-Phase-Lag Heat Conduction Model
by Stanislav Yu. Lukashchuk
Modelling 2024, 5(3), 776-796; https://doi.org/10.3390/modelling5030041 - 9 Jul 2024
Cited by 2 | Viewed by 1621
Abstract
This paper presents a new semi-explicit algorithm for parameters estimation in a time-fractional generalization of a dual-phase-lag heat conduction model with Caputo fractional derivatives. It is shown that this model can be derived from a general linear constitutive relation for the heat transfer [...] Read more.
This paper presents a new semi-explicit algorithm for parameters estimation in a time-fractional generalization of a dual-phase-lag heat conduction model with Caputo fractional derivatives. It is shown that this model can be derived from a general linear constitutive relation for the heat transfer by conduction when the heat conduction relaxation kernel contains the Mittag–Leffler function. The model can be used to describe heat conduction phenomena in a material with power-law memory. The proposed algorithm of parameters estimation is based on the time integral characteristics method. The explicit representations of the thermal diffusivity and the fractional analogues of the thermal relaxation time and the thermal retardation are obtained via a Laplace transform of the temperature field and utilized in the algorithm. An implicit relation is derived for the order of fractional differentiation. In the algorithm, this relation is resolved numerically. An example illustrates the proposed technique. Full article
(This article belongs to the Topic Applied Heat Transfer)
Show Figures

Figure 1

18 pages, 3733 KiB  
Article
Sensitivity of a Process for Heating Thin Metal Film Described by the Dual-Phase Lag Equation with Temperature-Dependent Thermophysical Parameters to Perturbations of Lag Times
by Ewa Majchrzak and Bohdan Mochnacki
Energies 2024, 17(10), 2252; https://doi.org/10.3390/en17102252 - 8 May 2024
Cited by 2 | Viewed by 1020
Abstract
In the paper, an equation with two delay times (dual-phase lag Equation (DPLE)) in a version that takes into account the dependence of thermophysical parameters (volumetric specific heat and thermal conductivity) on temperature is considered. In particular, an analysis of the sensitivity of [...] Read more.
In the paper, an equation with two delay times (dual-phase lag Equation (DPLE)) in a version that takes into account the dependence of thermophysical parameters (volumetric specific heat and thermal conductivity) on temperature is considered. In particular, an analysis of the sensitivity of transient temperature field in relation to disturbances in delay times (the relaxation and thermalization times) is performed. The sensitivity model concerns the process of heating an ultrathin metal layer with a laser beam. First, the equation with two delay times in the case of temperature-dependent thermophysical parameters is presented. Next, the sensitivity equations with respect to delay times are derived using the direct method. The algorithms for solving the basic and sensitivity tasks are also briefly presented. At the stage of computations, an authorial program based on the implicit scheme of a finite-difference method is developed. In the final part of the paper, examples of numerical solutions (for layers made from gold and nickel) are presented. The research conducted here shows that disturbances in the temperature field are clearly visible and depend, on the one hand, on the thermophysical parameters of the material, and on the other hand, on the intensity of heating with an external heat source. Full article
(This article belongs to the Collection Advances in Heat Transfer Enhancement)
Show Figures

Figure 1

19 pages, 14305 KiB  
Article
Colon Drug Delivery Systems Based on Swellable and Microbially Degradable High-Methoxyl Pectin: Coating Process and In Vitro Performance
by Saliha Moutaharrik, Luca Palugan, Matteo Cerea, Gabriele Meroni, Eleonora Casagni, Gabriella Roda, Piera Anna Martino, Andrea Gazzaniga, Alessandra Maroni and Anastasia Foppoli
Pharmaceutics 2024, 16(4), 508; https://doi.org/10.3390/pharmaceutics16040508 - 7 Apr 2024
Cited by 3 | Viewed by 2277
Abstract
Oral colon delivery systems based on a dual targeting strategy, harnessing time- and microbiota-dependent release mechanisms, were designed in the form of a drug-containing core, a swellable/biodegradable polysaccharide inner layer and a gastroresistant outer film. High-methoxyl pectin was employed as the functional coating [...] Read more.
Oral colon delivery systems based on a dual targeting strategy, harnessing time- and microbiota-dependent release mechanisms, were designed in the form of a drug-containing core, a swellable/biodegradable polysaccharide inner layer and a gastroresistant outer film. High-methoxyl pectin was employed as the functional coating polymer and was applied by spray-coating or powder-layering. Stratification of pectin powder required the use of low-viscosity hydroxypropyl methylcellulose in water solution as the binder. These coatings exhibited rough surfaces and higher thicknesses than the spray-coated ones. Using a finer powder fraction improved the process outcome, coating quality and inherent barrier properties in aqueous fluids. Pulsatile release profiles and reproducible lag phases of the pursued duration were obtained from systems manufactured by both techniques. This performance was confirmed by double-coated systems, provided with a Kollicoat® MAE outer film that yielded resistance in the acidic stage of the test. Moreover, HM pectin-based coatings manufactured by powder-layering, tested in the presence of bacteria from a Crohn’s disease patient, showed earlier release, supporting the role of microbial degradation as a triggering mechanism at the target site. The overall results highlighted viable coating options and in vitro release characteristics, sparking new interest in naturally occurring pectin as a coating agent for oral colon delivery. Full article
(This article belongs to the Section Drug Delivery and Controlled Release)
Show Figures

Figure 1

21 pages, 10338 KiB  
Article
Novel Series-Parallel Phase-Shifted Full-Bridge Converters with Auxiliary LC Networks to Achieve Wide Lagging-Leg ZVS Range
by Yunzhi Wang, Fei Sun, Jun Chen, Huafeng Cai and Shen Gao
Electronics 2024, 13(7), 1311; https://doi.org/10.3390/electronics13071311 - 31 Mar 2024
Cited by 2 | Viewed by 2330
Abstract
Under light load conditions, the phase-shifted full-bridge (PSFB) converter often has difficulty in realizing the zero-voltage switching (ZVS) of the lagging-leg by relying on the energy of its resonant inductor; however, for the series-parallel PSFB converter applied in high-power applications, the lagging-leg still [...] Read more.
Under light load conditions, the phase-shifted full-bridge (PSFB) converter often has difficulty in realizing the zero-voltage switching (ZVS) of the lagging-leg by relying on the energy of its resonant inductor; however, for the series-parallel PSFB converter applied in high-power applications, the lagging-leg still has the problem of difficult realization of ZVS. Based on this, the paper analyzes the reasons why the series-parallel PSFB converter has difficulty in achieving ZVS for the lagging-leg under light and heavy loads. Under interleaved control, the ZVS of the lagging-leg over the full load range is realized by adding an auxiliary LC branch at the midpoint of the lagging-leg of both submodules. Based on the double-bridge input-parallel-output-series (IPOS) PSFB converter, analyzing the working principle of the circuit after adding the auxiliary LC branch and extending it to the series-parallel PSFB converter. The design requirements of the LC auxiliary branch of the dual-bridge series-parallel PSFB converter are given and the effects of the LC auxiliary branch on the module operating state and device stress are analyzed. On this basis, an extension is carried out to give the working principle and design method of the auxiliary LC branch of the N-bridge series-parallel PSFB converter. Finally, a 100 kW Matlab/Simulink simulation model verifies the superior performance of the proposed LC auxiliary branch to realize the lagging-leg ZVS of the series-parallel PSFB converter under light and heavy loads and achieves a 1.09% peak efficiency improvement at rated load. Full article
(This article belongs to the Special Issue Wide and Ultrawide Band Gap Semiconductors: Materials and Devices)
Show Figures

Figure 1

21 pages, 14485 KiB  
Article
Analysis of Dual-Polarimetric Radar Observations of Precipitation Phase during Snowstorm Events in Jiangsu Province, China
by Lei Wang, Yi Wang, Mei Liu, Wei Chen and Chiqin Li
Atmosphere 2024, 15(3), 321; https://doi.org/10.3390/atmos15030321 - 4 Mar 2024
Viewed by 1563
Abstract
Based on ground observed data, S-band dual-polarization radar data, and ERA-5 reanalysis data, the statistical characteristics of polarimetric parameters and the application of melting layer (ML) and hydrometeor classification (HCL) products during eight snowstorm events in Jiangsu Province from 2020 to 2022 were [...] Read more.
Based on ground observed data, S-band dual-polarization radar data, and ERA-5 reanalysis data, the statistical characteristics of polarimetric parameters and the application of melting layer (ML) and hydrometeor classification (HCL) products during eight snowstorm events in Jiangsu Province from 2020 to 2022 were investigated. A heavy snowstorm that went through different phases of rain, sleet, and pure snow and that occurred on 29 December 2020 was also analyzed as a typical example. The results showed the following: During the phase transition between rain and snow in the Jiangsu region, the basic reflectivity factor ZH ≥ 27 dBZ, the zero-order lag correlation coefficient CC ≤ 0.93, and the differential reflectivity ZDR ≥ 1.0 dB were important indicators for judging the melting layer while the specific differential phase KDP changed slightly. The snowstorm event was well observed and recorded by the Yancheng dual-polarimetric radar, whose low value area of CC coincided mostly with the melting layer. The ML products and HCL products based on fuzzy-logic hydrometeor classification algorithms can help identify the melting layer and the properties of precipitation particles. ML products are more reliable when the melting layer is high and can better show the trends of melting layer decline. They can certainly serve as a reference for detecting and judging precipitation phase changes in winter in Jiangsu Province. Full article
(This article belongs to the Special Issue Data Assimilation for Predicting Hurricane, Typhoon and Storm)
Show Figures

Figure 1

21 pages, 11486 KiB  
Article
Performance of Smartphone BDS-3/GPS/Galileo Multi-Frequency Ionosphere-Free Precise Code Positioning
by Ruiguang Wang, Chao Hu, Zhongyuan Wang, Fang Yuan and Yangyang Wang
Remote Sens. 2023, 15(22), 5371; https://doi.org/10.3390/rs15225371 - 15 Nov 2023
Cited by 1 | Viewed by 2095
Abstract
The continuously improving performance of mass-market global navigation satellite system (GNSS) chipsets is enabling the prospect of high-precision GNSS positioning for smartphones. Nevertheless, a substantial portion of Android smartphones lack the capability to access raw carrier phase observations. Therefore, this paper introduces a [...] Read more.
The continuously improving performance of mass-market global navigation satellite system (GNSS) chipsets is enabling the prospect of high-precision GNSS positioning for smartphones. Nevertheless, a substantial portion of Android smartphones lack the capability to access raw carrier phase observations. Therefore, this paper introduces a precise code positioning (PCP) method, which utilizes Doppler-smoothed pseudo-range and inter-satellite single-difference methods. For the first time, the results of a quality investigation involving BDS-3 B1C/B2a/B1I, GPS L1/L5, and Galileo E1/E5a observed using smartphones are presented. The results indicated that Xiaomi 11 Lite (Mi11) exhibited a superior satellite data decoding performance compared to Huawei P40 (HP40), but it lagged behind HP40 in terms of satellite tracking. In the static open-sky scenario, the carrier-to-noise ratio (CNR) values were mostly above 25 dB-Hz. Additionally, for B1C/B1I/L1/E1, they were approximately 8 dB-Hz higher than those for B2a/L5/E5a. Second, various PCP models were developed to address ionospheric delay. These models include the IF-P models, which combine traditional dual-frequency IF pseudo-ranges with single-frequency ionosphere-corrected pseudo-ranges using precise ionospheric products, and IFUC models, which rely solely on single-frequency ionosphere-corrected pseudo-ranges. Finally, static and dynamic tests were conducted using datasets collected from various real-world scenarios. The static tests demonstrated that the PCP models could achieve sub-meter-level accuracy in the east (E) and north (N) directions, while achieving meter-level accuracy in the upward (U) direction. Numerically, the root mean square error (RMSE) improvement percentages were approximately 93.8%, 75%, and 82.8% for HP40 in the E, N, and U directions, respectively, in both open-sky and complex scenarios compared to single-point positioning (SPP). In the open-sky scenario, Mi11 showed an average increase of about 85.6%, 87%, and 16% in the E, N, and U directions, respectively, compared to SPP. In complex scenarios, Mi11 exhibited an average increase of roughly 68%, 75.9%, and 90% in the E, N, and U directions, respectively, compared to SPP. Dynamic tests showed that the PCP models only provided an improvement of approximately 10% in the horizontal plane or U direction compared to SPP. The triple-frequency IFUC (IFUC123) model outperforms others due to its lower noise and utilization of multi-frequency pseudo-ranges. The PCP models can enhance smartphone positioning accuracy. Full article
(This article belongs to the Special Issue GNSS Advanced Positioning Algorithms and Innovative Applications)
Show Figures

Figure 1

24 pages, 9154 KiB  
Article
Effect of Bending Deformation on the Lateral Force of Spinning Projectiles with Large Aspect Ratio
by Qi Liu, Juanmian Lei, Yong Yu and Jintao Yin
Aerospace 2023, 10(9), 810; https://doi.org/10.3390/aerospace10090810 - 15 Sep 2023
Cited by 2 | Viewed by 1492
Abstract
The bending deformation can affect the lateral force of spinning projectiles with large aspect ratios, thus interfering with their flight stability. Based on the established spin–deformation coupling motion model, the unsteady Reynolds averaged Navier–Stokes (URANS) equations are solved to simulate the flow over [...] Read more.
The bending deformation can affect the lateral force of spinning projectiles with large aspect ratios, thus interfering with their flight stability. Based on the established spin–deformation coupling motion model, the unsteady Reynolds averaged Navier–Stokes (URANS) equations are solved to simulate the flow over a large−aspect−ratio projectile undergoing spin and spin−deformation coupling motion by using the dual−time stepping method and dynamic mesh technique, obtaining the lateral force. Furtherly, the flow mechanism is analyzed for the changed lateral force induced by the bending deformation. The results indicate that the variation of transient lateral force for the head of a projectile is consistent with that of the deformation−induced additional sideslip angle; affected by the deformation−induced compression wave and expansion wave, the time−averaged lateral force for the middle of a projectile will be increased at small angles of attack, but changed little at large angles of attack; at small angles of attack, the change trend of transient lateral force for the tail of a projectile is similar to that of additional angle of attack caused by the deformation; at large angles of attack, the characteristic of phase lag is presented between the transient lateral force for the tail of a projectile and the additional sideslip angle. Full article
(This article belongs to the Special Issue Fluid Flow Mechanics (3rd Edition))
Show Figures

Figure 1

Back to TopTop