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Straw‐decomposing microbial inoculants (MIs) have been increasingly applied to straw‐amended soils. However, the interactive effects and underlying microbial mechanisms of straw and decomposing MIs on nitrous oxide (N2O) emissions remain unclear. Here, a pot experiment with an Aquic Inceptisol was conducted to determine soil N2O emissions and the abundance and composition of microbial functional genes under six amendments: wheat straw (W), Bacillus subtilis MI (B), Streptomyces rochei MI (S), a combination of straw and B. subtilis MI (WB), a combination of straw and S. rochei MI (WS), and a control without wheat straw or MI (C). Compared with the control, the amendments of straw, decomposing MIs, and their combinations decreased soil N2O emissions by 43%, 22–30%, and 46–60%, respectively. Mechanistically, the positive relationship between ammonia‐oxidizing bacteria (AOB) and soil potential nitrification rate (PNR), along with decreased AOB abundance (−36%) following straw and decomposing MI amendments, further suggested that AOB predominated soil nitrification and was responsible for the suppressed nitrification. In addition, straw amendment increased nirK gene abundance (by 48%) and potential denitrification rate (by 11%), while the increase in nosZI gene abundance (+25%) involved in N2O consumption contributed to the decrease in N2O emissions. Overall, the additive effect of straw and decomposing MIs on soil N2O emissions was associated with two amendment‐induced changes in the abundance and composition of AOB and straw‐stimulated the abundance of the nosZI gene. Our results revealed the potential for mitigating N2O emissions following the amendments of straw and MI by influencing soil N2O‐related microbial groups. [ABSTRACT FROM AUTHOR]

The temporal variation of heat budget in the lower layer of the eastern Ross Sea shelf (ERSS) is crucial for understanding the stability of ice shelves in the Ross Sea. In this study, a 6‐year (2005–2010) simulation from the Southern Ocean State Estimate (SOSE) is employed to analyse the interannual variations of heat budget in the lower layer of the ERSS and the controlling mechanisms. The results reveal that the annual change in the heat content of the study region is dominated by the horizontal heat advection term, and only in 2015 the vertical advection and diffusion terms also play an important role. The horizontal advection term is affected by the intrusion of warm circumpolar deep water (CDW) onto the shelf across the northern boundary of the ERSS, the transport of cold dense shelf water (DSW) from the western Ross Sea shelf, and the transport of CDW across the western boundary of the ERSS. The contributions of these physical processes to the change in annual heat content vary between years. The interannual variation of the CDW intrusion is associated with the strength of eddy activity over the slope, and the interannual variation of heat transports associated with DSW is affected by both the extent of DSW on the western shelf and the coastal circulations that affect the eastward spread of DSW. [ABSTRACT FROM AUTHOR]

To analyze social-economic causes of the regional ecological degradation, and avoid such problems as the complex circulation network and difficulty to identify laws caused by extended exergy analysis (EEA) previously applied at the national scale, this paper reduced spatial scale to the county scale and took Pengyang County in Ningxia as an example. Eco-economic system in Peng-yang County was divided into seven interrelated sectors. The exergy value of circulations in the eco-economic system including materials, labor and capital were calculated respectively to analyze the extended exergy characteristics of the driving sectors, factors and paths and evaluate their ecological efficiency. The results showed that agriculture and households were the main driving sectors of the eco-economic system in Pengyang County. The average exergy value of 31 flow paths among the sectors was 0.80 PJ. There were only 8 flow paths whose exergy values were higher than the average value. Eco-economic system in Pengyang County development was driven by two continuous flow paths, labor output of the households sector and demands of the households sector supported by other sectors. The mineral resources were massively exploited, and then directly exported to the outside, which could not promote the local development from the inside, but, on the contrary, increase the ecological environment pressure because of the over-exploitation. The eco-efficiency of Pengyang County in 2014 was 68.1%, almost equivalent to the by-level of the national scale at home and abroad ten years ago, mainly because of the lower eco-efficiencies of the service sector and households sector. EEA had the advantage of networking and structuring, could specify the sectors, factors and driven paths, and break through the bottleneck of driving mechanism research of the eco-economic system. EEA had certain adaptability to explore the operational principle and optimal pattern of the regional eco-economic system. Compared with the national scale, EEA at the regional scale could more easily identify the driving mechanism of eco-economic system, and could clearly guide the regional administrative department to reduce the ecological environment pressure.

Livelihood capital has a close relationship with the income and expenditure of farmers' households. For example, the survival strategies of farmers' households are determined by it and it also influences regional development mechanisms and models. Under the analysis framework of sustainable livelihoods, this study evaluated farmers' livelihood capital, income, and expenditure, based on a participatory rural appraisal and a statistical method, in the development-restricted ecological district of Ningxia, decomposed into the nationality, terrain, and type of farmers' household. Further, by using an index of non-farm business households, the correlations between the livelihood capital and income with the expenditure of farmers' households and the index of non-farm business households were quantified to understand the mechanism of regional development. The results showed that livelihood capital was generally low in the study area. In particular, the livelihood capital of Hui nationality households was slightly higher than that of Han nationality households, that of river valley households was higher than that of mountain households, and that of combined occupation households and non-farm business households was significantly higher than that of agricultural households. Moreover, there was a significant positive correlation between the net annual income of farmers' households and the non-agricultural index, human capital, physical capital, and financial capital, while a significant negative correlation existed between net annual income and natural capital. These findings suggested that efforts were required to enhance the capacity of the non-agricultural index and the human, material, and other capital in the study area. They also served as a guideline for the circulation of peasants' means of production in order to accelerate the polarization of natural capital.

The anomalous Hall effect (AHE) in the reactively sputtered epitaxial and polycrystalline γ'-Fe4N films is investigated systematically. The Hall resistivity is positive over the entire temperature range. The magnetization, carrier density and grain boundary scattering have a major impact on the AHE scaling law. The scaling exponent γ in the conventional scaling of ρAH ∝ ρ(γ)(xx) is larger than 2 in both the epitaxial and polycrystalline γ'-Fe4N films. Although γ > 2 has been found in heterogeneous systems due to the effects of the surface and interface scattering on AHE, γ > 2 is not expected in homogenous epitaxial systems. We demonstrated that γ > 2 results from residual resistivity (ρxx0) in γ'-Fe4N films. Furthermore, the side-jump and intrinsic mechanisms are dominant in both epitaxial and polycrystalline samples according to the proper scaling relation.

The present study aims to evaluate the performance of evaporation-assisted humidification–dehumidification (E-HDH) desalination, specifically direct evaporative (DE-HDH), indirect evaporative (IE-HDH), and Maisotsenko evaporative (ME-HDH) systems. To achieve this, a thermodynamic modeling approach is utilized, which incorporates the wet bulb effectiveness method, psychrometric relationships of humid air, and equations that govern heat and mass balance. The key performance indicators of the studied E-HDH desalination systems are estimated concerning operating parameters. The results show that the ME-HDH system is capable of producing a comparatively higher water production rate (WPR) ranging between 0.01 and 7.92 g/s as compared to the DE-HDH and IE-HDH systems. The sensible cooling flux was observed to be high at a dry-bulb temperature (Tdb) of 50 °C and relative humidity (RH) < 0.2, having a value of 5.26 kW for the DE-HDH system, followed by the ME-HDH system (3.23 kW) and the IE-HDH system (3.11 kW) due to relatively high mass flow rates. The latent heat flux was observed to be relatively high in the case of the ME-HDH system. Minimum specific energy consumption was observed from the ME-HDH system, and consequently, a maximum gain output ratio (3.32) was realized. In addition, the study realized that an increment in air velocity and wet bulb effectiveness significantly improves the WPR. In accordance with the climatic conditions of the studied Saudi Arabia cities, it has been realized that Al-Hofuf and Riyadh produce relatively high WPRs with minimum energy consumption. In the case of Al-Hofuf, the average WPR was recorded as 185.51 kg/day, followed by Riyadh (180.33 kg/day). The energy required was estimated to be 0.042 kWh/kg and 0.034 kWh/kg for both cities, accordingly. [ABSTRACT FROM AUTHOR]

This paper proposes a low-complexity model predictive current control (MPCC) strategy based on extended voltage vectors to enhance the computational efficiency and steady-state performance of three-phase series-winding permanent magnet synchronous motors (TPSW-PMSMs). Compared to conventional MPCC methods, this approach increases the number of candidate voltage vectors in the alpha–beta plane from 8 to 38, thereby achieving better steady-state performance. Specifically, the proposed method reduces the total harmonic distortion (THD) by 59%. To improve computational efficiency, a two-stage filtering strategy is employed, significantly reducing the computational burden. The number of voltage vectors traversed in one control period is reduced from 38 to a maximum of 4, achieving an 89% reduction in traversals. Additionally, to mitigate the impact of zero-sequence currents, zero-sequence current suppression is implemented within the control system for effective compensation. By combining low computational complexity, reliable steady-state performance, and real-time control capabilities, this strategy provides an efficient solution for TPSW-PMSM systems. Simulation results validate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Symmetry is widely present in science and daily life. And the internal structure of surface-mounted permanent magnet synchronous motors (PMSMs) has good symmetry. This article is dedicated to studying the tracking problem of PMSMs with adaptive and backstepping control methods. The research objective of this study is to design new adaptive controllers U q and U d , which enable the state of the motor position servo system to asymptotically and stably track the given signals of the system. They can suppress the impact of changes in B, J, and T L and can also enhance the robustness of the system. (i) The strongly coupled current and speed, variation of parameters over time, and nonlinearity of motor torque objectively pose significant challenges in the design of adaptive tracking controllers for PMSMs. (ii) Adaptive control technology and backstepping control methods are used for designing controllers for the PMSMs. (iii) After rigorous reasoning, an intelligent adaptive tracking control strategy for the PMSMs has been derived, which is for the direct axis current and the angle. (iv) The new adaptive tracking controllers are superior to existing controllers in that they can strongly suppress the disturbance of system parameters J, T L , and B, make the system state asymptotically stable, and achieve good tracking performance for the given signals. The results of the simulation indicate the validity of the designed control strategy. [ABSTRACT FROM AUTHOR]

A three‐phase squirrel cage induction motor (IM) drive system supplied by a new modified structure of Γ−Z${{\Gamma}} - {\mathrm{Z}}$ impedance source inverter (Γ−Z${{\Gamma}} - {\mathrm{Z}}$ ISI) is proposed. The two main goals are speed (torque) control, and efficiency improvement. The modified Γ−Z${{\Gamma}} - {\mathrm{Z}}$ ISI has the ability to boost the input voltage. This improves the operation range of the system particularly for limited DC‐link voltage conditions. A first order integral‐terminal sliding mode (ITSM) controller is designed incorporating the motor and inverter dynamic model equations. The maximum efficiency strategy based on Lagrange's theorem is achieved by optimizing the motor input power (input energy) as the objective function under the constant load torque. The maximum efficiency strategy using energy saving is suitable for electric drive system applications. Also, the control method is resilient to any change in motor parameters and unmodulated system dynamics. Furthermore, its output control error can be eliminated in a limited interval. Finally, a prototype of the system using a 1.5 kW three‐phase squirrel cage IM is provided and several tests are conducted. The experimental results show the efficacy of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the latest developments in fuzzy logic (FL) applications across critical domains which include energy harvesting (EH), ambient conditioning systems (ACS), and robotics and autonomous systems (RAS), highlighting FL's capability to address nonlinearities and uncertainties in diverse technological environments. Through a detailed comparative analysis of research trends over the past decade, it underscores the increasing significance of FL in EH and RAS, contrasting with the sustained interest in ACS. Furthermore, the evaluation of different fuzzy inference systems across domains provides valuable insights into their specific strengths and limitations, aiding researchers and practitioners in making informed decisions aligned with their application needs. Additionally, the paper explores advanced modifications and hybridizations of FL, such as swarm intelligence and integrations with other control strategies, emphasizing the necessity for robust and adaptive FL systems. The review also identifies key open problems and potential research directions, such as the demand for adaptive FL systems in EH and advanced optimization techniques in ACS and RAS. Overall, this state-of-the-art review not only summarizes the current state of FL applications but also outlines a roadmap for future research, offering valuable insights for advancing FL's role in handling uncertainties and nonlinearities in complex systems. [ABSTRACT FROM AUTHOR]

Speed of convergence and robustness against disturbances affecting a dynamical system are of great importance in real-life applications. To satisfy these requirements, another approach called predefined time control has been developed in the last decade, which ensures the convergence of the states of a class of dynamical systems to the desired reference value in a time set by the control designer at will. However, previously proposed predefined time control algorithms have drawbacks that need to be tackled. For this reason, the authors present another form of predefined time control algorithm that can be coupled with any observer (in the case where not all the states of the system can be measured) or any other robust controller to robustify the system against matched disturbances. The development shows that the necessary form of the control law can be obtained using basic integration and backstepping. The performance of the control law is demonstrated through a series of numerical simulations utilizing the mathematical model of a permanent magnet synchronous motor (PMSM). The results show that the proposed control algorithm is, indeed, robust against any matched disturbance, and the convergence of the system states is ensured independently of any initial condition in the time set by the control designer at will. [ABSTRACT FROM AUTHOR]

Inrush current is still a persistent problem affecting the quality of the power system. This paper presents the theoretical aspects of this transient phenomenon, the simulation of the phenomenon for prediction purposes and its measurement in a test laboratory. In the operation of power transformers, there may also be cases where electrical phenomena affecting the operation of transformers may overlap. When power transformers are in operation, there may also be cases where electrical phenomena affecting their operation overlap. This paper includes a study describing such a situation, where the maximum value of the inrush current is amplified by the fact that the series resonance condition has been met. The intersection of these electrical phenomena resulted in internal and external electrical discharges that led to the overhaul of a 440 MVA transformer; the description of this situation is based on field data. The paper focuses on real information and situations that support the development of a maintenance management schedule based on accurate and up-to-date data. The information presented in this paper will be particularly useful to personnel specializing in power transformer design and/or those monitoring/operating high power transformers in the energy sector, but can also be a teaching aid for students interested in such transient phenomena. [ABSTRACT FROM AUTHOR]

Transient flow frequently occurs in water delivery systems, including various flow regimes such as water hammer, free surface flow, and slug flow. Current models often oversimplify these phenomena by simulating single-phase flow or using simplistic one-dimensional assumptions for the gas-water interface, neglecting interface instability. Although two-fluid models can address some of these issues, they cannot simulate open channel flow and have not yet been applied to transient flow scenarios. To date, no single model has been able to simultaneously simulate all these flow regimes while overcoming these limitations. To address this gap, the two-fluid model is enhanced in this paper. For water hammer simulation, a gas volume fraction of zero is assumed, and a TVB unsteady friction model is introduced to enhance numerical accuracy. For open channel flow, a variable wave speed equation and a new state equation are presented. Despite the different state equations required for various flow regimes, a Roe-type scheme is introduced to solve the two-fluid model. This approach accurately simulates water hammer, free surface flow (including open channel flow and stratified flow), and slug flow. An experimental pipeline system is designed to validate the proposed model's ability to simulate water hammer. Additionally, several cases are used to verify the model's capability in simulating open channel flow, stratified flow, and slug flow. The model accurately predicts the occurrence of slug flow, consistent with experimental flow pattern maps, and effectively simulates the evolution of slug flow, closely matching the measured gas-water interface. The effects of gas volume fraction, pipe length, and pipe slope on slug flow are systematically discussed. Results indicate that smaller initial gas volume fractions, longer pipe lengths, and upward pipe slopes increase the likelihood of slug flow generation within the pipeline, which should be minimized during design. Abbreviations: TVB: Trikha-Vardy-Brown model; Cr: Courant number [ABSTRACT FROM AUTHOR]

This study presents a novel approach that integrates model order reduction (MOR) and generalized stochastic collocation (gSC) to enhance robust design optimization (RDO) of viscoelastic damped composite structures under material and geometric uncertainties. The proposed methodology systematically reduces computational burden while maintaining the required accuracy. A projection-based MOR is chosen to alleviate the substantial computational costs associated with nonlinear eigenvalue problems. To minimize the sampling size for uncertainty propagation (UP) while effectively addressing diverse probability density distributions, a gSC method incorporating statistical moment computation techniques is developed. Pareto optimal solutions are determined by combining the proposed MOR and gSC approaches with a well-established Non-dominated Sorting Genetic Algorithm II (NSGA-II) algorithm, which accounts for robustness in handling design variables, objectives, and constraints. The results of the four examples illustrate the efficacy of the proposed MOR and gSC methods, as well as the overall RDO framework. Notably, the findings demonstrate the feasibility of this approach for practical applications, driven by a significant reduction in computational costs. This establishes a solid foundation for addressing complex optimization challenges in real-world scenarios characterized by various uncertainties. [ABSTRACT FROM AUTHOR]

For deep analysis on the regional environmental economic system, the paper analyzes the mutual relation of regional economy development, environmental quality, environmental pollution, and builds the theoretical basis. Then, the economy-pollution-environment quality three-dimensional coupling evaluation model for district is constructed. It includes economic development level index, environmental pollution index, and environmental quality index. The model is a cube, which has spatialization and visualization characteristics. The model includes 8 sub cubes, which expresses 8 types of state, e. g. low pollution-inferior quality-low level of economic development etc. The model can be used to evaluate the status of region, divide development phase, analyze evolution trend etc. It has two ways including relative meaning evaluation (RME) and absolute meaning evaluation (AME). Based on the model, Yinchuan City in the Ningxia Hui Autonomous Region is used as an example for the empirical study. Using RME, compared with Guangzhou city, The result shows that the Yinchuan City has been a high pollution-low quality-low level of economic development state for a long period during 1996-2010. After 2007, the state changed to a high pollution-high quality-low level of economic development. Now, the environmental quality of Yinchuan city gets better, but pollutant discharge pressure is high, and tends to be the break point of high environment quality and low environment. With AME, using national standard, the Yinchuan City remains a high pollution-low quality-low level of economic development state during 1996-2010. Empirical research verifies that different target reference areas and relevant national standards have different main parameters, the evaluating result has an flexible range. The dimensionless data enhances the coupling of index. The data position in model increases the visibility to the environmental management decisions. The model improves mismatches of calculated data size, time asymmetry of spatial data, verification of the former multi-target coupling model.

The main purpose of our work is to investigate the performance of wave breaking and its effect on wave retrieval in data acquired from the Chinese Gaofen-3 (GF-3) synthetic aperture radar (SAR) at C-band and the German TerraSAR-X (TS-X) at X-band. The SAR images available for this study included 140 GF-3 images acquired in quad-polarization strip (QPS) mode and 50 dual-polarized (vertical-vertical (VV) and horizontal-horizontal (HH)) TS-X images acquired in stripmap (SM) mode. Moreover, these images were collocated with the waves simulated by the numeric WAVEWATCH-III (WW3) (version 5.16) model and HYbrid Coordinate Ocean Model (HYCOM) current. In particular, a few images covered the moored buoys monitored by the National Data Buoy Center (NDBC) of the National Oceanic and Atmospheric Administration (NOAA). The comparison between the WW3-simulated results and the significant wave heights (SWHs) from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data (ERA-5) showed that the correlation coefficient (COR) was 0.4–0.6 with a root mean squared error (RMSE) of about 0.2 m at SWHs of 0–4 m. The winds were inverted using VV-polarized geophysical model functions (GMFs), e.g., CSARMOD-GF for the GF-3 images and XMOD2 for the TS-X images. The Bragg resonant roughness in the normalized radar cross section (NRCS) was simulated using a radar backscattering model and the SAR-derived wind, WW3-simulated wave parameters, and HYCOM current. Then, the contribution of the non-polarized (NP) wave breaking to the SAR data was estimated by the VV-polarized NRCS, the HH-polarized NRCS, and the polarization ratio (PR) of the co-polarized Bragg resonant components in the NRCS. Because co-polarized Bragg resonant components in the NRCSs have poor results, due to the saturation for wind speeds greater than 20 m/s, the analysis of wave breaking is excluded at such conditions. The results revealed that the backscattering signal in the C-band was more sensitive to wave breaking than the backscattering signal in the X-band. Interestingly, the ratio had a linear correlation with wind speed. Moreover, the variation in the bias (inverted SWH minus WW3 simulation) showed that the bias increased as the wind speed (>8 m/s) and whitecap coverage (>0.005) increased. Following this rationale, wave retrieval during tropical cyclones should consider the influence of wave breaking. [ABSTRACT FROM AUTHOR]

The development of distant-talk measurement systems has been attracting attention since they can be applied to many situations such as security and disaster relief. One such system that uses a device called a laser Doppler vibrometer (LDV) to acquire sound by measuring an object's vibration caused by the sound source has been proposed. Different from traditional microphones, an LDV can pick up the target sound from a distance even in a noisy environment. However, the acquired sounds are greatly distorted due to the object's shape and frequency response. Due to the particularity of the degradation of observed speech, conventional methods cannot be effectively applied to LDVs. We propose two speech enhancement methods that are based on two-stage processing with deep neural networks for LDVs. With the first proposed method, the amplitude spectrum of the observed speech is first restored. The phase difference between the observed and clean speech is then estimated using the restored amplitude spectrum. With the other proposed method, the low-frequency components of the observed speech are first restored. The high-frequency components are then estimated by the restored low-frequency components. The evaluation results indicate that they improved the observed speech in sound quality, deterioration degree, and intelligibility. [ABSTRACT FROM AUTHOR]

High precision temperature measurements are a transversal need in a wide area of physical experiments. Space-borne gravitational wave detectors are a particularly challenging case, requiring both high precision and high stability in temperature measurement. In this contribution, we present a design able to reach 1 μ K / Hz in most of the measuring band down to 1 mHz, and reaching 20 μ K / Hz at 0.1 mHz. The scheme is based on resistive sensors in a Wheatstone bridge configuration which is AC modulated to minimize the 1/f noise. As a part of our study, we include the design of a test bench able to guarantee the high stability environment required for measurements. We show experimental results characterising both the test bench and the read-out, and discuss potential noise sources that may limit our measurement. [ABSTRACT FROM AUTHOR]

Unlabelled: Concentrations of Zn, Cu, Cr, Pb and Cd in 96 topsoil samples collected from the northern Hebin Industrial Park were measured by the atomic absorption detector (AAD). Spatial variability was identified by geostatistical analysis with the aid of GS + 3.0 and ArcGIS 9.0. Temporal variability of five heavy metals was contrasted to the concentration in 1985 of the Ningxia second soil census. Google earth maps in years of 2003, 2004, 2009 and 2011 have been analyzed to find the variation of the geographical distribution of factories in study Area. Result showed that mean concentrations of Zn, Cu, Cr, Pb and Cd were 100.29, 352.86, 77.56, 50.52, 4.06 mg x kg(-1), respectively, and were all higher than the background values. Using the second level of environmental quality standard for soils of China as the criterion, Zn, Cr, Pb were not risk, Cu, Cd were mild contamination and serious contamination. Spatial distribution of the concentration of the five heavy metals varies with prevailing wind direction, from the northwest to southeast, increasing gradually. Meanwhile, there were several hotspots. Google earth map analysis showed that in the northeast and southeast part appeared a large number of factories after 2009, which should be the main sources of the five heavy metals in soils. In the lowlying southwest part, although there was no factory, soils still have been polluted heavily because of another adjacent industrial area in Inner Mongolia Autonomous Region and the smoke dust was blocked by the Helan Mountain along its west., Conclusions: (1) The number of the enterprise increased and trans-boundary pollution led to the high heavy metal concentration in surface soil of study area; (2) In northwest China, because of the strong wind, smoke dusts spread very long and distribution range was extensive, and low terrain area and enterprise distribution pattern lead to the island distribution.

We report a chemical route for the preparation of monodisperse Fe-Ni nanoparticles with tunable compositions and sizes. Unlike commonly used synthetic approaches that involve the simultaneous reduction of metal precursors in the presence of reducing agents, the approach developed in this study utilizes pre-formed Ni nanoparticles to react with Fe(III) acetylacetonate in high boiling-point solvents, wherein newly-generated Fe atoms diffuse into Ni nanoparticles to form Fe-Ni nanoparticles. The analytic results of powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) show that the as-synthesized Fe-Ni nanoparticles possess a face-centered cubic (fcc) crystalline structure and have a spherical or near-spherical morphology. X-ray photoelectron spectroscopy (XPS) study reveals metallic characteristics for the chemical state of Fe and Ni. The particle morphology and size distribution of the as-synthesized Fe-Ni nanoparticles are regulated by the pre-formed Ni nanoparticles, while the composition can be adjusted to some extent by the ratio of Fe precursor to Ni nanoparticles. Magnetic measurements reveal a superparamagnetic characteristic above the blocking temperature for the as-synthesized Fe-Ni nanoparticles. The synthetic approach may also be applied to other bimetallic nanoparticle systems.

Fiber-reinforced polymers (FRPs) are widely used within civil structural applications either for structural retrofitting or new constructions. This is due to their appreciable mechanical properties such as high stiffness and strength, resistance to environmental effects, as well low density. Through the years, such peculiarities have encouraged researchers to apply FRP cables within the design of prestressing systems, where steel cables are systematically adopted. However, the brittleness intrinsic to FRP materials necessitates additional efforts to design the anchorage devices. In fact, tendons are here subjected to stress peaks, which need to be controlled in order to prevent the premature failure of the cable. Following this goal, authors recently studied an optimized split-wedge anchorage, for 12 mm-diameter pultruded-carbon-fiber-reinforced polymer (PCFRP) tendons, adopting double-angle (DA) wedges, and compared its performance with a single-angle (SA) wedge configuration. Tensile tests were performed on 3 SA and 2 DA prototypes, respectively, through a universal testing machine: the DA configuration exploited the average cable capacity (257 kN) once, denoting a maximum efficiency. The obtained experimental results are utilized, in the framework of the present work, to calibrate contact parameters of nonlinear finite element models. The presented numerical results helped to assess benefits of the proposed configurations and the behavior of the anchorage components: the DA configuration turned out to satisfactorily avoid stress peak superpositions on the cable, with a reduction in pressure in the loading end of the cable with respect to the SA model. [ABSTRACT FROM AUTHOR]

Considering the effect of surrounding rock on lining in the design of tunnel lining within fractured rock masses is challenging, particularly in accurately predicting the reserved deformation of the tunnel. This study bases a rock mass classification method and the established Hoek–Brown (H-B) strength criterion to assess the deformation characteristics of the surrounding rock. It establishes a more scientifically rigorous theoretical calculation method for the reserved deformation of tunnel linings that accounts for the rock–lining interaction. An optimization design approach for the lining structure, based on the synergistic effect and considering the stress safety of the concrete lining and the rock's displacement release rate, is proposed. Case analysis is utilized to validate the safety of the lining design in the study section through computational verification. The recommended optimized lining parameters are identified: the support time is initiated when the tunnel wall's surrounding rock deforms by 9 mm, and the lining thickness is optimized to 47 cm, which is approximately 36.5% less than the pre-optimization thickness. This precise optimization of support timing and lining thickness enhances both the safety and economic efficiency of the Wufengshan Tunnel. The method allows for the calculation of the optimal combination of support time and lining thickness tailored to different surrounding rock conditions, offering significant reference value for tunnel lining optimization. [ABSTRACT FROM AUTHOR]

Marine current power is attracting more attention as a renewable energy option. Similar to wind power, marine current power often requires a maximum power point tracking (MPPT) method to optimize power extraction from the free‐flowing water. Research into MPPT methods for marine current power remains limited. Therefore, this paper presents a comprehensive investigation of MPPT methods for marine current power, building upon similar research in wind power. Three methods, namely the optimal tip speed ratio (OTSR), optimal torque (OT), and two variants of the perturb and observe (P&O) method, are explored. Using a simulation model developed for a specific marine current energy converter, where hydrodynamic calculations are coupled with electrical simulations, the study demonstrates that the OTSR method achieves MPPT with a comparably fast convergence time. After a change in water speed, the OTSR method achieves optimal operation within two turbine rotations. Additionally, the P&O methods are shown to achieve MPPT, albeit with a significantly longer convergence time. However, the P&O methods can be more convenient since no model of the system is required, and no water speed measurements are necessary. The proposed implementation of the OT method underperforms but positions the system close to the optimal operational point. [ABSTRACT FROM AUTHOR]

This study analyzed the effects of airflow characteristics on the temperature distribution and drying uniformity of paddy during convective drying. Simulations of the drying process with varying airflow inlet and outlet positions were conducted using COMSOL Multiphysics 6.1 software. The determination coefficient (R2) between the simulated data and experimental values of Sample1 (S1), Sample2 (S2), and Sample3 (S3) was calculated, and its average values were 0.964, 0.963, 0.963, and 0.967, respectively. This study demonstrates that the airflow direction and outlet location have a significant impact on the temperature uniformity of the paddy. The vortex structure generated by the obstruction of the sidewalls and paddy influences both the airflow and temperature distribution within the drying chamber. When the outlet was on the left side and the inlet airflow was in a vertical orientation (VO), the temperature distribution of the paddy exhibited higher temperatures in the edge regions and lower temperatures in the center, with a maximum temperature difference of around 16 °C. The time required for the temperature to reach equilibrium with the outlet positioned on the left was 28.6% shorter than with the outlets positioned in the center or on both sides. Moreover, the temperature uniformity of the three paddy samples was better under this condition. The developed model accurately reflected the paddy drying process. It could also be used to analyze the optimal heating uniformity, providing a technical basis for the design of grain dryers. [ABSTRACT FROM AUTHOR]

Variable-temperature convective drying (VTCD) is a promising technology for obtaining high-quality dried mushrooms, particularly when considering rehydration capacity. However, accurate numerical models for variable-temperature convective drying and rehydration of shiitake mushrooms are lacking. This study addresses this gap by employing a model with thermo–hydro and mechanical bidirectional coupling to investigate five dehydration characteristics (moisture ratio, drying rate, temperature, evaporation rate, and volume shrinkage ratio) and a drying load characteristic (enthalpy difference) during VTCD. Additionally, a mathematical model combining drying and rehydration is proposed to analyze the effect of VTCD processes on the rehydration performance of shiitake mushrooms. The results demonstrate that, compared to constant-temperature drying, VTCD-dried mushrooms exhibit moderate shrinkage rates and drying time (16.89 h), along with reduced temperature variation and evaporation rate gradient (Max. 1.50 mol/(m3·s)). VTCD also improves enthalpy stability, reducing the maximum drying load by 58.84% compared to 338.15 K constant-temperature drying. Furthermore, drying time at medium temperatures (318.15–328.15 K) greatly influences rehydration performance. This study quantitatively highlights the superiority of variable-temperature convective drying, offering valuable insights for optimizing the shiitake mushroom drying processes. [ABSTRACT FROM AUTHOR]

Minimising opposing forces is a matter of interest to most cyclists. These forces arise from passage through air ('drag') and interaction with the road surface ('resistance'). Recent work recognises that resistance forces arise not only from the deformation of the tyre ('rolling resistance') but also from irregularities in the road surface ('roughness resistance'), which lead to power dissipation in the body of the rider through vibration. The latter effect may also have an adverse impact on human health. In this work we offer a quantitative theory of roughness resistance and vibration that links these effects to a surface characterisation in terms of the International Roughness Index (IRI). We show that the roughness resistance and the Vibration Dose Value (or VDV, the usual vibration dosage metric) can be expressed in terms of elementary formulae. The roughness resistance depends only on the vertical stiffness of the bicycle and the roughness index. Surprisingly, other apparently relevant parameters, such as physiological characteristics of the bicycle rider and other features of the bicycle, do not enter. For roads of moderate roughness, roughness resistance is larger than rolling resistance. For very rough roads, roughness resistance is larger than aerodynamic drag. So only on roads of high quality (in most jurisdictions, accounting for less than 10% of the total) can roughness resistance be ignored. Roughness resistance can be mitigated by reducing the vertical stiffness of the bicycle. In common with other recent reports, we find that almost any cycling activity will breach public health guidelines relating to Vibration Dose Value. [ABSTRACT FROM AUTHOR]

The contact between the wheel and the rail heavily affects the dynamic behaviour of railway vehicles and their running safety. The real-time knowledge of wheel-rail contact forces is tricky due to the several running conditions of the train and the combined tribological and wear characteristics of wheels and rails. Furthermore, their measurement and that of track irregularities, sensitive to the harshness of the wheel-rail contact, require dedicated sensors. Therefore, the development of strategies for estimating wheel-rail contact features is essential to perform the condition monitoring of rails to improve the safety related to the entire railway system. A nonlinear model-based estimation procedure, based on a Central Difference Kalman Filter, is proposed in this work to estimate the lateral wheel-rail contact forces and moments, including the identification of lateral track irregularities in the estimation process related to rails. Furthermore, the developed estimation technique can be used as a tool to monitor continuously the track conditions through in-service railway vehicles, coupled with the possibility to improve the effectiveness of control systems onboard them by estimating wheel-rail contact interactions through a model-based estimator, which is fed by measurements obtained by the typical set of sensors adopted for condition monitoring purposes on railway vehicles. [ABSTRACT FROM AUTHOR]

Nanocomposites (NCs) consisting of zero-valent iron nanoparticles (nZVI) immobilized in chitosan (CS) were prepared and employed for the removal of hexavalent chromium (Cr(VI)) from both synthetic and real wastewater. Medium (MCS)- and high (HCS)-molecular-weight chitosan and stabilization with carboxymethylcellulose (CMC) and different nZVI loads were explored. Characterization through scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS) and X-ray diffraction (XRD) revealed millimeter-sized spheres with micrometer-sized nZVI clusters randomly distributed. Better nanoparticle dispersion was observed in NCs from the CMC-MCS and HCS combinations. Fourier-transform infrared spectroscopy (FTIR) analysis indicated that CS binds to Fe(II) or Fe(III) on the surface of nZVI through its functional groups -CONH-, -N-H, and -C-OH and through the - COO − functional group of CMC, forming a bidentate bridge complex. Through experiments with synthetic waters, it was found that the elimination of Cr(VI) was favored by lowering the pH, obtaining the maximum percentage of Cr(VI) removal at pH 5.5. With real waters, it was shown that increasing the mass of NCs also improved the removal of Cr(VI), following a pseudo-second-order adsorption kinetics. The synthesized materials show great potential for applications in environmental remediation, showing good efficiency in the removal of Cr(VI) in wastewater. [ABSTRACT FROM AUTHOR]

Biopesticides are considered as the effective measure to combat environmental consequences brought by chemical pesticides. However, due to the comparatively high price of biopesticides and unreasonable government subsidies, the trade-off between economy, society and environment represents a daunting task for pesticide supply chains. This study establishes a pesticide supply chain including manufacturers, retailer and government to study the production and sales strategies of pesticides under two different structures: monopoly and duopoly. Based on the equilibrium and numerical analyses, we find that: first, only when the government subsidy falls within a reasonable range, it can incentivise the chemical pesticide manufacturer to produce biopesticides in both monopoly and duopoly markets. Interestingly, the subsidy can improve the profit of pesticide supply chain in monopoly market, however the consumer surplus and social welfare are greater in duopoly market with the increase of subsidy. Second, the profit of pesticide supply chain is better after launching biopesticide and the retailer gains more profits in duopoly market than in monopoly market with the increase of farmer's biopesticide acceptance. Third, the launch of biopesticides can decrease the influence of environment pollution in both market structures, and less environmental impact in monopoly market. [ABSTRACT FROM AUTHOR]

The automotive market is very competitive and demands consistently improving the technologies used and reducing the product cost and dimensions with each product model iteration. Hence, it is important to have access to well-defined reference designs of high-quality products to evaluate new ideas and technologies. This paper provides readers with a numerical model of such a high-quality product, i.e., the IPMSM-type traction motor from the fourth generation of the Toyota Prius hybrid transaxle. The presented results also serve for a discussion regarding the design decisions of the Toyota engineers and the applicability of the linearized machine model for the approximated torque calculations. In the introductory section, a brief history of the Prius model and references to the reverse engineering reports are given. Afterward, the machine dimensions, material properties, and winding configuration are described. Then, the model is validated with the torque measurements at constant speed. The simulation results are presented in the next chapters, and the numerical source data are supplied to the reader. Finally, the design philosophy of the Toyota drive is briefly discussed in comparison with the BMWi3 drive and the results are concluded in the last section. [ABSTRACT FROM AUTHOR]

Since robustness is only maintained on the sliding-mode surface, sliding mode control is inherently non-globally stable. Therefore, reducing the time to reach the sliding mode is crucial for enhancing sliding mode robustness. To improve the performance of conventional super-twisting reaching law (CSTRL) further, we propose a fast-terminal super-twisting reaching law (FTSTRL) designed to improve the quality of sliding mode control. This approach incorporates a terminal term and an exponential term with the CSTRL to ensure rapid convergence. The effectiveness of the designed FTSTRL is validated by comparing it to the CSTRL and a new sliding mode reaching law, demonstrating its superior performance. Finally, integrated square error (ISE), integrated time square error (ITSE), integrated absolute error (IAE), and integrated time absolute error (ITAE) are employed for detailed comparative and quantitative analyses of the simulation results. [ABSTRACT FROM AUTHOR]

Vehicular control systems are required to be both extremely reliable and robust to different environmental conditions, e.g. load or tyre–road friction. In this paper, we extend a new paradigm for state estimation, called Twin-in-the-Loop filtering (TiL-F), to the estimation of the unknown parameters describing the vehicle operating conditions. In such an approach, a digital-twin of the vehicle (usually already available to the car manufacturer) is employed on-board as a plant replica within a closed-loop scheme, and the observer gains are tuned purely from experimental data. The proposed approach is validated against experimental data, showing to significantly outperform the state-of-the-art solutions. [ABSTRACT FROM AUTHOR]

This paper applies information dissemination theory, consumer information behavior theory, signaling theory, and value co-creation theory to investigate the effects of companies' online platform operations from a tourism company perspective. We gathered data from 51 listed tourism companies in China between 1992 and 2022 to test these impacts. Results showed that using online platforms could improve listed tourism companies' performance, but not all platforms played the same role. Of the three online platforms we tested, official websites and WeChat accounts had significant positive influences on listed tourism companies' performance; Weibo had no effect. Group research revealed that online platforms most effectively enhanced hotels' performance, followed by comprehensive tourism companies. Resource tourism companies received no obvious impact. [ABSTRACT FROM AUTHOR]

This study aimed to prevent health damage caused by chemical exposure among cleaning workers who use cleaning agents and disinfectants in facility management and kitchen areas. We analyzed 5 years of measurement data (2016–2020) for cleaning workers across various industries in Korea, and conducted an exposure survey and health risk assessment for the two most frequently measured substances (i.e., 2-butoxyethanol and sodium hydroxide) and representative substances generated by their combined use (i.e., chlorine and chloroform). The findings indicate that when chlorine was generated by mixing hypochlorite-based disinfectants (e.g., bleach) with acidic cleaners containing substances such as nitric, hydrochloric, or citric acid, the risk index for chlorine gas (based on the 95th percentile exposure values) was 5.65 in the facility management cleaning industry, exceeding the acceptable threshold of 1. Because of the high usage and exposure frequency of cleaning and disinfecting agents and the common practice of mixing multiple products to enhance cleaning efficacy, it is necessary to manage hazardous risk factors by providing education on appropriate working methods, supplying personal protective equipment, and installing ventilation systems for these workers. Further research on the health risk assessment of combined chemical use is needed. [ABSTRACT FROM AUTHOR]

The significant expansion of renewable energies has led to an increased importance of storage systems. Decentralized storage solutions, including Home Battery Energy Storage Systems (HBESSs) and District Battery Energy Storage Systems (DBESSs), play a crucial role in this context. This study compares individual HBESSs with a community-used DBESS regarding the grade of autarky and self-consumption, specifically focusing on a planned residential area consisting of 36 single-family houses. A simulation tool was developed to conduct load flow simulations based on household electricity consumption, wallbox profiles for electric vehicle charging, and photovoltaic generation data across various battery capacities and system boundaries. The results demonstrate that the DBESS, compared to individual HBESSs with equivalent cumulative battery capacities, can achieve a maximum increase in the grade of autarky of up to 11.6 %, alongside an 8.0 % increase in the grade of self-consumption for the given use case. In terms of capacity, the DBESS allows for a saving of up to 68% compared to HBESS to achieve similar results for the studied neighborhood. [ABSTRACT FROM AUTHOR]

In recent years, with the widespread application of indoor inspection robots, high-precision, robust environmental perception has become essential for robotic mapping. Addressing the issues of visual–inertial estimation inaccuracies due to redundant pose degrees of freedom and accelerometer drift during the planar motion of mobile robots in indoor environments, we propose a visual SLAM perception method that integrates wheel odometry information. First, the robot's body pose is parameterized in SE(2) and the corresponding camera pose is parameterized in SE(3). On this basis, we derive the visual constraint residuals and their Jacobian matrices for reprojection observations using the camera projection model. We employ the concept of pre-integration to derive pose-constraint residuals and their Jacobian matrices and utilize marginalization theory to derive the relative pose residuals and their Jacobians for loop closure constraints. This approach solves the nonlinear optimization problem to obtain the optimal pose and landmark points of the ground-moving robot. A comparison with the ORBSLAM3 algorithm reveals that, in the recorded indoor environment datasets, the proposed algorithm demonstrates significantly higher perception accuracy, with root mean square error (RMSE) improvements of 89.2% in translation and 98.5% in rotation for absolute trajectory error (ATE). The overall trajectory localization accuracy ranges between 5 and 17 cm, validating the effectiveness of the proposed algorithm. These findings can be applied to preliminary mapping for the autonomous navigation of indoor mobile robots and serve as a basis for path planning based on the mapping results. [ABSTRACT FROM AUTHOR]

To improve the Solar Array Drive Assembly (SADA) system, a servo control method known as Linear Active Disturbance Rejection Control (LADRC) is introduced, utilizing a speed loop for a Permanent Magnet Synchronous Motor (PMSM). This method serves as an alternative to the conventional proportional–integral (PI) controller, which exhibits a limited stability margin. The use of the LADRC controller leads to decreased overshoot and enhances the system's robustness against disturbances. First, the mathematical representation of the PMSM alongside the dynamic model of the solar wing is established. Following that, the application of the Lyapunov stability theory is employed to illustrate the stability of the drive system utilizing LADRC, thereby validating the stability of the SADA. Lastly, simulation experiments are performed using the MATLAB2021a/Simulink digital environment. The simulation results under various operational conditions indicate the significant improvement in stability compared to the PI controller, achieving the stability level of 9.603 × 10 − 5 , demonstrates enhanced performance in terms of speed and resistance to disturbances. [ABSTRACT FROM AUTHOR]

Bond wire lift-off is one of the major failure mechanisms in the insulated gate bipolar transistor (IGBT) modules. Detecting the fault of bond wires is important to avoid the open-circuit fault of IGBT to ensure the reliable operation of power converters. In this paper, we propose a novel bond wire fatigue detection method for IGBT, which could be used in normal working conditions. Firstly, we investigated the dependence of bond wire fatigue on heatsink thermal resistance. An aging rate K was proposed to compare the measured thermal resistance with the initial value, which could indicate the bond wire fatigue. Then, this proposed method was verified by simulation and experimental results under different current levels. Finally, a power cycling test was used to show the aging process of the IGBT module, which shows the feasibility of proposed method. [ABSTRACT FROM AUTHOR]

Intersecting disciplines, as an important trend in the development of modern academic research and education, have exerted a profound and positive influence on scientific research activities. Based on control theory and fractional-order theory, this paper presents a novel approach for the speed regulation of a permanent magnet synchronous motor (PMSM) in the presence of uncertainties and external disturbances. The proposed method is a composite control based on a model-free sliding mode and a fractional-order ultra-local model. The model-free sliding mode is a control strategy that utilizes the sliding mode control methodology without explicitly relying on a mathematical model of the system being controlled. The fractional-order ultra-local model is a mathematical representation of a dynamic system that incorporates the concept of fractional-order derivatives. The core of the controller is a new type of fractional-order fast nonsingular terminal sliding mode surface, which ensures high robustness, quick convergence, while preventing singularity. Moreover, a novel fractional-order nonlinear extended state observer is proposed to estimate both internal and external disturbances of the fractional-order ultra-local model. The stability of the system is analyzed using both the Lyapunov stability theory and the Mittag–Leffler stability theory. The analysis confirms the convergence stability of the closed-loop system under the proposed control scheme. The comparison results indicate that the proposed composite control based on the fractional-order ultra-local model is a promising solution for regulating the speed of PMSMs in the presence of uncertainties and disturbances. [ABSTRACT FROM AUTHOR]

This paper studies the non-singular practical fixed-time neural adaptive control issues for multi-input and multi-output (MIMO) nonlinear systems with non-strict feedback form. Neural networks (NN) are used to estimate the unknown nonlinearities and deal with the problem of an algebraic loop. Under the framework of the backstepping control design, a practical fixed-time adaptive NN control method is developed by using the adding power integration technology. According to the Lyapunov function theory, it is proved that the closed-loop system is practical fixed-time stable, and the system can track the desired reference signal within a fixed time. Finally, the proposed practical fixed-time control method is applied to a multi-motor control platform, which proves the effectiveness of the control method. [ABSTRACT FROM AUTHOR]

Control chart is an important method in Statistical Process Control, which is used to study how a process changes over time. The exponential distribution is one of the commonly used models for fitting data, especially in areas such as component life, aviation accidents, or health-care processes. In order to further improve the sensitivity of the control chart, we propose an exponentially weighted moving average control chart with a variable sampling interval scheme, denoted as VSIEWMA-T control chart, for monitoring exponentially distributed quality characteristics (e.g. Urinary Tract Infections data). In this paper, the average time to signal property of the proposed control chart is investigated using the Markov chain method. In addition, parameter optimization algorithms for known or unknown shift levels are provided. Subsequently, numerical analysis shows that the proposed control chart outperforms other competitive control charts. Finally, an example of urinary tract infections data is provided for illustration. [ABSTRACT FROM AUTHOR]

Let $ \mathcal {O} $ O denote the ring of integers of a quadratic field $ \mathbb {Q}(\sqrt {-7}) $ Q (− 7). In 2022, Murtuza and Garge [Murtuza N, Garge A. Universality of certain diagonal quadratic forms for matrices over a ring of integers, Indian Journal of Pure and Applied Mathematics, Published online; December 2022.] gave a necessary and sufficient condition for a diagonal quadratic form $ a_1X_1^2+a_2X_2^2+a_3X_3^2 $ a 1 X 1 2 + a 2 X 2 2 + a 3 X 3 2 where $ a_i\in \mathbb {\mathcal {O}} $ a i ∈ O for $ 1\leq i \leq ~3 $ 1 ≤ i ≤ 3 for representing all $ 2\times 2 $ 2 × 2 matrices over $ \mathcal {O} $ O . Let K denote a quadratic field such that its ring of integers $ \mathcal {O}_K $ O K is a principal ideal domain and 2 is a product of two distinct primes. It is a well-known fact that $ \mathbb {Q}(\sqrt {-7}) $ Q (− 7) is the only imaginary quadratic field with the above properties. Let $ D_K $ D K denote the discriminant of K. We have $ D_K\equiv 1(\text{mod }8) $ D K ≡ 1 (mod 8) if and only if 2 is a product of two distinct primes in $ \mathcal {O}_K $ O K . With $ \mathcal {O}_K $ O K as above, in this paper we generalize our earlier result. We give a necessary and sufficient condition for a diagonal quadratic form $ {\sum _{i=1}^{m}a_iX_i^2} $ ∑ i = 1 m a i X i 2 where $ a_i\in \mathcal {O}_K $ a i ∈ O K , $ 1\leq i \leq m $ 1 ≤ i ≤ m to represent all $ 2\times 2 $ 2 × 2 matrices over $ \mathcal {O}_K $ O K . This result is a conjecture stated in [Murtuza N, Garge A. Universality of certain diagonal quadratic forms for matrices over a ring of integers, Indian Journal of Pure and Applied Mathematics, Published online; December 2022]. [ABSTRACT FROM AUTHOR]

The magnetic correlations at the superconductor/ferromagnet (S/F) interfaces play a crucial role in realizing dissipation-less spin-based logic and memory technologies, such as triplet-supercurrent spin-valves and 'π' Josephson junctions. Here we report the observation of an induced large magnetic moment at high-quality nitride S/F interfaces. Using polarized neutron reflectometry and DC SQUID measurements, we quantitatively determined the magnetization profile of the S/F bilayer and confirmed that the induced magnetic moment in the adjacent superconductor only exists below T C. Interestingly, the direction of the induced moment in the superconductors was unexpectedly parallel to that in the ferromagnet, which contrasts with earlier findings in S/F heterostructures based on metals or oxides. First-principles calculations verified that the unusual interfacial spin texture observed in our study was caused by the Heisenberg direct exchange coupling with constant J∼4.28 meV through d -orbital overlapping and severe charge transfer across the interfaces. Our work establishes an incisive experimental probe for understanding the magnetic proximity behavior at S/F interfaces and provides a prototype epitaxial 'building block' for superconducting spintronics. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study solvability and stability of stochastic differential-algebraic equations (SDAEs) with delay. It is difficult to investigate these properties for SDAEs with delay because of the singularity of the leading coefficient matrix. An index-ν concept is derived for solvability of these equations. Stability of SDAEs with delay is studied by using the method of Lyapunov functions and comparison principle. An example is given to illustrate the results. To the best of our knowledge, these results are novel for SDAEs with delay. [ABSTRACT FROM AUTHOR]

Heterogeneous phase combined flooding (HPCF) has been a promising technology used for enhancing oil recovery in heterogeneous mature reservoirs. However, the injectivity and propagation behavior of preformed particle gel (PPG) in low–medium-permeability reservoir porous media is crucial for HPCF treatment in a low–medium-permeability reservoir. Thus, the injectivity and propagation behavior of preformed particle gel in a low–medium-permeability reservoir were systematically studied by conducting a series of sand pack flooding experiments. The matching factor (δ) was defined as the ratio of the average size of PPG particles to the mean size of pore throats and the pressure difference ratio (β) was proposed to characterize the injectivity and propagation ability of PPG. The results show that with the increase in particle size and the decrease in permeability, the resistance factor and residual resistance factor increase. With the increase in the matching factor, the resistance factor and residual resistance factor increase. The higher the resistance factor and residual resistance factor are, the worse the injectivity of particles is. By fitting the relationship curve, PPG injection and propagation standards were established: when the matching coefficient is less than 55 and β is less than 3.4, PPG can be injected; when the matching coefficient is 55–72 and β is 3.4–6.5, PPG injection is difficult; when the matching coefficient is greater than 72 and β is greater than 6.5, PPG cannot be injected Thus, the matching relationship between PPG particle size and reservoir permeability was obtained. This research will provide theoretical support for further EOR research and field application of heterogeneous phase combined flooding. [ABSTRACT FROM AUTHOR]

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To improve the accuracy of the sensorless control system for permanent magnet synchronous motors, this paper proposes the based on fractional order integral sliding mode theory in the model reference adaptive system observer. The purpose of this approach is to enhance the robustness of the system. Furthermore, this paper introduces the second-order sliding mode reaching law to suppress chattering phenomena and improve the control accuracy of the observer. Simulation results show that this strategy achieves excellent dynamic and static performance. [ABSTRACT FROM AUTHOR]