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
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (46)

Search Parameters:
Keywords = summation basis

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
25 pages, 5570 KB  
Article
Influence of Multi-Source Electromagnetic Coupling on NVH in Automotive PMSMs
by Tingwei Du, Jinbo Wang, Weihai Zhang and Wei Liao
Electronics 2025, 14(23), 4652; https://doi.org/10.3390/electronics14234652 - 26 Nov 2025
Viewed by 239
Abstract
Persistent discrepancies remain in the perceived far-field noise of automotive permanent-magnet synchronous motors (PMSMs) and the predictions of conventional NVH simulations. To bridge this gap, a Tri-source Electromagnetic Coupling NVH Integrated Framework (Tri-ECNVH) is developed, in which air-gap electromagnetic force harmonics, torque ripple, [...] Read more.
Persistent discrepancies remain in the perceived far-field noise of automotive permanent-magnet synchronous motors (PMSMs) and the predictions of conventional NVH simulations. To bridge this gap, a Tri-source Electromagnetic Coupling NVH Integrated Framework (Tri-ECNVH) is developed, in which air-gap electromagnetic force harmonics, torque ripple, and cogging torque are treated as a coupled excitation system rather than as independent sources. Traditional workflows usually superpose their responses in the power domain, which tends to underestimate the radiating contribution of torque-related excitations and neglect their phase and order coupling with radial electromagnetic forces. In the proposed Tri-ECNVH framework, the three sources are mapped into the order domain, aligned by spatial order, and applied to the stator with phase consistency, so that inter-source coupling and cross terms are explicitly retained along a unified electromagnetic–structural–acoustic chain. Acoustic radiation is evaluated by prescribing the normal velocity on the stator outer surface as a Neumann boundary condition and computing the far-field A-weighted sound pressure level (SPL) using a boundary element method (BEM) model. Numerical results reveal pronounced cooperative amplification of the three sources at critical orders and within perceptually sensitive frequency bands; relative to independent-source modeling with power-domain summation, Tri-ECNVH predicts peak levels that are typically 5–10 dB higher and reproduces the spectral envelope and peak–valley evolution more faithfully. The framework therefore offers a practical, radiation-oriented basis for multi-source noise mitigation in traction PMSMs and helps narrow the gap between simulation and perceived sound quality in automotive applications. Full article
Show Figures

Figure 1

29 pages, 4047 KB  
Review
Phenomenal Diversity of the Photosynthetic Apparatus Evolved in Aerobic Anoxygenic Phototrophs
by Vladimir Yurkov and Katia Messner
Microorganisms 2025, 13(11), 2446; https://doi.org/10.3390/microorganisms13112446 - 25 Oct 2025
Viewed by 677
Abstract
Aerobic anoxygenic phototrophs (AAPs) are intrinsically paradoxical; these species use a pathway commonly found in oxygen-deprived environments called anoxygenic photosynthesis, as a supplementary energy source to their obligately aerobic respiration. At the surface, such a combination seems odd, but AAPs thrive in a [...] Read more.
Aerobic anoxygenic phototrophs (AAPs) are intrinsically paradoxical; these species use a pathway commonly found in oxygen-deprived environments called anoxygenic photosynthesis, as a supplementary energy source to their obligately aerobic respiration. At the surface, such a combination seems odd, but AAPs thrive in a plethora of environments and are phylogenetically broad, suggesting that this feature is advantageous and ecologically valuable. The range of habitats and taxonomy have been reviewed, yet the main element which unites the group, their anoxygenic photosynthesis, which is diverse in its components, has not received the deserved attention. The intricate light-capturing photosynthetic complex forms the site of photon-induced energy transfer and therefore, the core basis of the process. It has two parts: the reaction center and light harvesting complex(es). The variability in composition and overall usage of the apparatus is also reflected in the genome, specifically the photosynthetic gene cluster. In this review, what is known about the differences in structure, light wavelength absorption range, activity, and related genomic content and the insights into potential AAP evolution from anaerobic anoxygenic phototrophs will be discussed. The work provides an elegant summation of knowledge accumulated about the photosynthetic apparatus and prospects that can fill yet remaining gaps. Full article
(This article belongs to the Collection Feature Papers in Environmental Microbiology)
Show Figures

Figure 1

18 pages, 1807 KB  
Article
Homomorphic Cryptographic Scheme Based on Nilpotent Lie Algebras for Post-Quantum Security
by Aybeyan Selim, Muzafer Saračević and Azra Ćatović
Symmetry 2025, 17(10), 1666; https://doi.org/10.3390/sym17101666 - 6 Oct 2025
Viewed by 1503
Abstract
In this paper, the use of nilpotent Lie algebras as the basis for homomorphic encryption based on additive operations is explored. The g-setting is set up over gln(Zq)) and the group [...] Read more.
In this paper, the use of nilpotent Lie algebras as the basis for homomorphic encryption based on additive operations is explored. The g-setting is set up over gln(Zq)) and the group G=exp(g), and it is noted that the exponential and logarithm series are truncated by nilpotency in a natural way. From this, an additive symmetric conjugation scheme is constructed: given a message element M and a central randomizer Uzg, we encrypt =KexpM+UK1 and decrypt to M=log(K1CK)U. The scheme is additive in nature, with the security defined in the IND-CPA model. Integrity is ensured using an encrypt-then-MAC construction. These properties together provide both confidentiality and robustness while preserving the homomorphic functionality. The scheme realizes additive homomorphism through a truncated BCH-sum, so it is suitable for ciphertext summations. We implemented a prototype and took reproducible measurements (Python 3.11/NumPy) of the series {10,102,103,104,105} over 10 iterations, reporting the medians and 95% confidence intervals. The graphs exhibit that the latency per operation remains constant at fixed values, and the total time scales approximately linearly with the batch size; we also report the throughput, peak memory usage, C/M expansion rate, and achievable aggregation depth. The applications are federated reporting, IoT telemetry, and privacy-preserving aggregations in DBMS; the limitations include its additive nature (lacking general multiplicative homomorphism), IND-CPA (but not CCA), and side-channel resistance requirements. We place our approach in contrast to the standard FHE building blocks BFV/BGV/CKKS nd the emerging NIST PQC standards (FIPS 203/204/205), as a well-established security model with future engineering optimizations. Full article
(This article belongs to the Section Computer)
Show Figures

Figure 1

12 pages, 3358 KB  
Article
Self-Powered Au/ReS2 Polarization Photodetector with Multi-Channel Summation and Polarization-Domain Convolutional Processing
by Ruoxuan Sun, Guowei Li and Zhibo Liu
Sensors 2025, 25(17), 5375; https://doi.org/10.3390/s25175375 - 1 Sep 2025
Viewed by 847
Abstract
Polarization information is essential for material identification, stress mapping, biological imaging, and robust vision under strong illumination, yet conventional approaches rely on external polarization optics and active biasing, which are bulky, alignment-sensitive, and power-hungry. A more desirable route is to encode polarization at [...] Read more.
Polarization information is essential for material identification, stress mapping, biological imaging, and robust vision under strong illumination, yet conventional approaches rely on external polarization optics and active biasing, which are bulky, alignment-sensitive, and power-hungry. A more desirable route is to encode polarization at the pixel level and read it out at zero bias, enabling compact, low-noise, and polarization imaging. Low-symmetry layered semiconductors provide persistent in-plane anisotropy as a materials basis for polarization selectivity. Here, we construct an eight-terminal radial ‘star-shaped’ Au/ReS2 metal-semiconductor junction array pixel that operates in a genuine photovoltaic mode under zero external bias based on the photothermoelectric effect. Based on this, electrical summation of phase-matched multi-junction channels increases the signal amplitude approximately linearly without sacrificing the two-lobed modulation depth, achieving ‘gain by stacking’ without external amplification. The device exhibits millisecond-scale transient response and robust cycling stability and, as a minimal pixel unit, realizes polarization-resolved imaging and pattern recognition. Treating linear combinations of channels as operators in the polarization domain, these results provide a general pixel-level foundation for compact, zero-bias, and scalable polarization cameras and on-pixel computational sensing. Full article
(This article belongs to the Special Issue Recent Advances in Optoelectronic Materials and Device Engineering)
Show Figures

Figure 1

17 pages, 1980 KB  
Review
Functional Optical Balance in Cataract Surgery: A Review
by Dillan Cunha Amaral, Pedro Lucas Machado Magalhães, Alex Gonçalves Sá, Alexandre Batista da Costa Neto, Flávio Moura Travassos de Medeiros, Milton Ruiz Alves, Jaime Guedes and Ricardo Noguera Louzada
Optics 2025, 6(3), 36; https://doi.org/10.3390/opt6030036 - 8 Aug 2025
Viewed by 2577
Abstract
Functional Optical Balance (FOB) is a novel personalized strategy for intraocular lens (IOL) selection in cataract surgery, designed to reconcile the trade-off between optical quality and spectacle independence. FOB is a core concept aiming to maximize visual performance by treating the two eyes [...] Read more.
Functional Optical Balance (FOB) is a novel personalized strategy for intraocular lens (IOL) selection in cataract surgery, designed to reconcile the trade-off between optical quality and spectacle independence. FOB is a core concept aiming to maximize visual performance by treating the two eyes as a synergistic pair. One eye (often the dominant eye) is optimized for pristine optical quality (typically distance vision with a high-contrast monofocal or low-add IOL). In contrast, the fellow eye is optimized for extended depth of focus and pseudoaccommodation (using an extended depth-of-focus or multifocal/trifocal IOL) to reduce dependence on glasses. This review introduces the rationale and theoretical basis for FOB, including the interplay of depth of focus and optical aberrations, binocular summation, ocular dominance, and neuroadaptation. We discuss the clinical implementation of FOB: how the first-eye results guide the second-eye IOL choice in a tailored “mix-and-match” approach, as well as practical workflow considerations such as patient selection, ocular measurements, and decision algorithms. We also review current evidence from the literature on asymmetric IOL combinations (e.g., monofocal plus multifocal, or EDOF plus trifocal), highlighting visual outcomes, patient satisfaction, and remaining evidence gaps. Overall, FOB represents a paradigm shift toward binocular, patient-customized refractive planning. Early clinical reports suggest it can deliver a continuous range of vision without significantly compromising visual quality, though careful patient counseling and case selection are essential. Future directions include the integration of advanced diagnostics, artificial intelligence-driven IOL planning tools, and adaptive optics simulations to refine this personalized approach further. The promise of FOB is to improve cataract surgery outcomes by achieving an optimal balance: one that provides each patient with excellent visual quality and functional vision across distances, tailored to their lifestyle and expectations. Full article
Show Figures

Figure 1

27 pages, 13275 KB  
Article
Seismic Response Analysis of a Vibrating Stirred Steel Fiber Concrete Frame Structure Based on Probability Density Evolution
by Liang Huang, Shuaitao Li, Di Zhang, Wenze Wang, Jianguo Xu and Shizhan Xu
Buildings 2024, 14(12), 3862; https://doi.org/10.3390/buildings14123862 - 30 Nov 2024
Viewed by 1155
Abstract
In this paper, an experimental study of steel fiber concrete using vibration mixing technology and the probability density evolution theory is applied to establish a nonlinear stochastic seismic response model for multistory concrete frame structures considering the randomness of structural parameters. The random [...] Read more.
In this paper, an experimental study of steel fiber concrete using vibration mixing technology and the probability density evolution theory is applied to establish a nonlinear stochastic seismic response model for multistory concrete frame structures considering the randomness of structural parameters. The random evolution characteristics of the structural response are studied and analyzed, and a reliability analysis method for concrete frame structures based on PDEM theory is proposed. The equations are solved by the finite difference method in the TVD format, and the probability distribution of the deformation index of the concrete frame structure is obtained by summation, where the reliability is given according to the limit value of the index. The results confirm that the PDEM theory can accurately assess the functional reliability of the structure, and it is also found that the randomness of the structural parameters has a significant effect on its nonlinear dynamic response law, and that consideration of the randomness of the structural parameters at the early stage of the design can be of great help to the seismic resistance of the structure. This study not only provides a scientific basis for the optimization of the performance of steel fiber concrete but also provides a new perspective and tool for the analysis of probability density evolution in the field of structural earthquake engineering. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
Show Figures

Figure 1

35 pages, 1568 KB  
Article
A Theory of Functional Connections-Based hp-Adaptive Mesh Refinement Algorithm for Solving Hypersensitive Two-Point Boundary-Value Problems
by Kristofer Drozd, Roberto Furfaro and Andrea D’Ambrosio
Mathematics 2024, 12(9), 1360; https://doi.org/10.3390/math12091360 - 29 Apr 2024
Cited by 1 | Viewed by 1597
Abstract
This manuscript introduces the first hp-adaptive mesh refinement algorithm for the Theory of Functional Connections (TFC) to solve hypersensitive two-point boundary-value problems (TPBVPs). The TFC is a mathematical framework that analytically satisfies linear constraints using an approximation method called a constrained expression. [...] Read more.
This manuscript introduces the first hp-adaptive mesh refinement algorithm for the Theory of Functional Connections (TFC) to solve hypersensitive two-point boundary-value problems (TPBVPs). The TFC is a mathematical framework that analytically satisfies linear constraints using an approximation method called a constrained expression. The constrained expression utilized in this work is composed of two parts. The first part consists of Chebyshev orthogonal polynomials, which conform to the solution of differentiation variables. The second part is a summation of products between switching and projection functionals, which satisfy the boundary constraints. The mesh refinement algorithm relies on the truncation error of the constrained expressions to determine the ideal number of basis functions within a segment’s polynomials. Whether to increase the number of basis functions in a segment or divide it is determined by the decay rate of the truncation error. The results show that the proposed algorithm is capable of solving hypersensitive TPBVPs more accurately than MATLAB R2021b’s bvp4c routine and is much better than the standard TFC method that uses global constrained expressions. The proposed algorithm’s main flaw is its long runtime due to the numerical approximation of the Jacobians. Full article
(This article belongs to the Special Issue Dynamics and Control Using Functional Interpolation)
Show Figures

Figure 1

29 pages, 4330 KB  
Article
High-Precision Calculation Using the Method of Analytical Regularization for the Cut-Off Wave Numbers for Waveguides of Arbitrary Cross Sections with Inner Conductors
by Elena Vinogradova, Paul Smith and Yury Shestopalov
Appl. Sci. 2024, 14(6), 2265; https://doi.org/10.3390/app14062265 - 7 Mar 2024
Cited by 2 | Viewed by 1640
Abstract
A method for the accurate calculation of the cut-off wavenumbers of a waveguide with an arbitrary cross section and a number of inner conductors is demonstrated. Concepts of integral and infinite-matrix (summation) operator-valued functions depending nonlinearly on the frequency spectral parameter provide a [...] Read more.
A method for the accurate calculation of the cut-off wavenumbers of a waveguide with an arbitrary cross section and a number of inner conductors is demonstrated. Concepts of integral and infinite-matrix (summation) operator-valued functions depending nonlinearly on the frequency spectral parameter provide a secure basis for formulating the spectral problem, and the Method of Analytical Regularization is employed to implement an effective algorithm. The algorithm is based on a mathematically rigorous solution of the homogeneous Dirichlet problem for the Helmholtz equation in the interior of the waveguide, excluding the regions occupied by the inner conductor boundaries. A highly efficient method of calculating the cut-off wavenumbers and the corresponding non-trivial solutions representing the modal distribution is developed. The mathematical correctness of the problem statement, the method, and the ability to calculate the cut-off wavenumbers with any prescribed and proven accuracy provide a secure basis for treating these as “benchmark solutions”. In this paper, we use this new approach to validate previously obtained results against our benchmark solutions. Furthermore, we demonstrate its universality in solving some new problems, which are barely accessible by existing methods. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
Show Figures

Figure 1

16 pages, 1345 KB  
Article
Development and Proposal of a Novel Scoring System to Classify Dry Mouth Severity
by Julie Frigaard, Håvard Hynne and Janicke Liaaen Jensen
Appl. Sci. 2023, 13(21), 11758; https://doi.org/10.3390/app132111758 - 27 Oct 2023
Cited by 5 | Viewed by 4079
Abstract
Dry mouth is a common complaint with unmet treatment needs, reflected by the fact that more than 500 trials are registered on ClinicalTrials.gov. Comparisons across studies, however, are difficult as inclusion criteria vary widely. Additionally, the terms xerostomia and hyposalivation are often not [...] Read more.
Dry mouth is a common complaint with unmet treatment needs, reflected by the fact that more than 500 trials are registered on ClinicalTrials.gov. Comparisons across studies, however, are difficult as inclusion criteria vary widely. Additionally, the terms xerostomia and hyposalivation are often not separated. Thus, the aim of the present work was to develop a dry mouth severity score (DMSS) that incorporates published questionnaires and measures both xerostomia and hyposalivation and proposes a grading system that can be used as a common basis for inclusion into clinical trials. The DMSS was developed through the use of data from patients in the Dry Mouth Clinic, University of Oslo, Norway. Five groups of patients (n = 131) and controls (n = 59) were included: primary Sjögren’s syndrome, non-Sjögren’s syndrome, radiated head and neck cancer, psychiatry, and controls. The proposed DMSS includes five parameters with corresponding cut-off values given 1 point (p) each: the General Xerostomia Question ≥ 2, Summated Xerostomia Inventory ≥ 11, Clinical Oral Dryness Score ≥ 6, and secretion of unstimulated and chewing-stimulated whole saliva with cut-off values at ≤0.1 mL/min and ≤0.7 mL/min, respectively. The proposed score range for DMSS is 0–3, where score 0 corresponds to 0p, score 1 to 1–2p, score 2 to 3p, and score 3 to 4–5p. In the patient group, 65% had a high DMSS of 2 or 3, while 78% of the controls scored 0. The sensitivity and specificity were high (0.93 and 0.78, respectively), and the internal reliability was satisfactory (Cronbach’s alpha 0.80). The proposed DMSS represents a novel method to uniformly classify dry mouth patients for applicable comparison between clinical trials. Full article
Show Figures

Figure 1

12 pages, 4113 KB  
Communication
Driving Source of Change for Ionosphere before Large Earthquake -Vertical Ground Motion-
by Chia-Hung Chen, Koichiro Oyama, Hau-Kun Jhuang and Uma Das
Remote Sens. 2023, 15(18), 4556; https://doi.org/10.3390/rs15184556 - 16 Sep 2023
Cited by 2 | Viewed by 1960
Abstract
This paper discusses the relationship between the vertical ground motion and ionospheric disturbances before the Kumamoto earthquake on 16 April 2016, in Kyushu, Japan, using the vertical ground motion measured by slant gauges widely distributed in Kyushu, and the NmF2 observed by ionosondes [...] Read more.
This paper discusses the relationship between the vertical ground motion and ionospheric disturbances before the Kumamoto earthquake on 16 April 2016, in Kyushu, Japan, using the vertical ground motion measured by slant gauges widely distributed in Kyushu, and the NmF2 observed by ionosondes in Japan and another region. We provide evidence that vertical ground motion excites internal gravity waves (IGWs) that disturb changes in the ionospheric plasma density. From the spectral analysis results of the vertical ground motion data, the summation of various period (frequency) components analyzed from the original data of the slant gauge shows a possible correlation with the change of NmF2 before the earthquake. On the other hand, the influence of the geomagnetic disturbance on vertical ground motion seems to exist. However, we cannot confirm that vertical ground motion is influenced by the geomagnetic disturbance (Kp index) and that the earthquake is triggered by the geomagnetic disturbance. There are two conditions for the vertical ground motion to disturb variations in the ionospheric plasma density: (1) The effective vertical ground motion period should be shorter than 5 h. In addition, (2) vertical ground motion should continue to exist so that wave energy can be continuously injected into the atmosphere. A possible mechanism with which to modify the ionosphere is discussed. The results of this study can provide a basis for the future ionospheric precursors of earthquakes by using the vertical ground motion. Full article
Show Figures

Graphical abstract

15 pages, 3221 KB  
Article
Developmental Indicators of Chrysomya nigripes Aubertin under Different Constant Temperature Conditions and an Application Case for Estimating the PMImin
by Yi Guo, Gengwang Hu, Liangliang Li, Mingqing Liao, Jiangfeng Wang, Yu Wang and Luyang Tao
Insects 2023, 14(9), 729; https://doi.org/10.3390/insects14090729 - 25 Aug 2023
Cited by 4 | Viewed by 2343
Abstract
Chrysomya nigripes Aubertin, 1932, is a Calliphoridae species that colonize the carcass after the bloat phase and remains for long periods. Some early sarcosaprophagous insects complete one generation of development and are no longer associated with the corpse and surrounding environment, while C. [...] Read more.
Chrysomya nigripes Aubertin, 1932, is a Calliphoridae species that colonize the carcass after the bloat phase and remains for long periods. Some early sarcosaprophagous insects complete one generation of development and are no longer associated with the corpse and surrounding environment, while C. nigripes larvae and pupae remain, providing a basis for the estimation of the minimum postmortem interval (PMImin) for highly decomposed or skeletonized carcasses. However, data on the growth and development of this species are not yet complete. As a result, we studied the developmental patterns of C. nigripes at eight constant temperatures ranging from 16–37 °C and constructed various developmental models, including the isomorphen diagram, isomegalen diagram, linear thermal summation model, nonlinear thermodynamic Optim SSI model, and logistic regression model. Chrysomya nigripes could not complete the entire developmental process at 16 °C, although it could be completed at other temperatures. The mean developmental times (±SD) of C. nigripes from egg to adult at 19 °C, 22 °C, 25 °C, 28 °C, 31 °C, 34 °C, and 37 °C were 644.9 ± 36.8 h, 422.9 ± 20.1 h, 323.1 ± 13.9 h, 246.6 ± 11.2 h, 202.5 ± 1.8 h, 191.5 ± 3.8 h, and 191.8 ± 2.0 h, respectively. The thermal summation constant (K) and lower critical thermal threshold (TL) derived from the linear thermal summation models were 4083.00 ± 293.39 degree hours and 12.52 ± 0.83 °C, respectively. In addition, TL, intrinsic optimum temperature (TΦ), and upper critical thermal threshold (TH) estimated by the optimized nonlinear thermodynamic Optim SSI model were 15.76 °C, 24.88 °C, and 38.15 °C, respectively. This study provides more comprehensive developmental data of C. nigripes for PMImin estimation. Full article
(This article belongs to the Section Medical and Livestock Entomology)
Show Figures

Figure 1

17 pages, 318 KB  
Article
Representations by Beurling Systems
by Kazaros Kazarian
Mathematics 2023, 11(17), 3663; https://doi.org/10.3390/math11173663 - 24 Aug 2023
Viewed by 1103
Abstract
We prove that a Beurling system with FHp(D),1p< is an M—basis in Hp(D) with an explicit dual system. Any function [...] Read more.
We prove that a Beurling system with FHp(D),1p< is an M—basis in Hp(D) with an explicit dual system. Any function fHp(D),1p< can be expanded as a series by the system {zmF(z)}m=0. For different summation methods, we characterize the outer functions F for which the expansion with respect to the corresponding Beurling system converges to f. Related results for weighted Hardy spaces in the unit disc are studied. Particularly we prove Rosenblum’s hypothesis. Full article
(This article belongs to the Special Issue Fourier Analysis, Approximation Theory and Applications)
23 pages, 12109 KB  
Article
Suitability Evaluation and Engineering Matching for Agricultural Development of Barren Grassland in Mountainous Area: A Case Study of County Scale
by Zhaoya Chen, Niandong Guo and Yaheng Chen
Sustainability 2023, 15(16), 12330; https://doi.org/10.3390/su151612330 - 13 Aug 2023
Cited by 1 | Viewed by 1455
Abstract
Barren grasslands are an important reserve resource of cultivated land in mountainous areas. The exploitation of barren grassland for agricultural use has played a role in ensuring food security and people’s livelihood in many countries and regions. The suitability evaluation of agricultural-use development, [...] Read more.
Barren grasslands are an important reserve resource of cultivated land in mountainous areas. The exploitation of barren grassland for agricultural use has played a role in ensuring food security and people’s livelihood in many countries and regions. The suitability evaluation of agricultural-use development, based on the conditions of barren grassland itself and the engineering matching, can not only ensure the sustainable development of agriculture but also avoid the ecological negative effects caused by excessive engineering. According to the research, the agricultural development of barren grassland needs to be evaluated from the two angles of natural suitability and engineering suitability, and an innovative “index level serial number summation method” is proposed. The suitability of barren grassland for agricultural use development was divided into three categories: barren grassland suitable for cultivation, barren grassland suitable for forestry, and barren grassland suitable for prataculture. The barren grassland suitable for cultivation was selected for type division and engineering-accurate matching. Taking Tang County as a research area, an example was provided through a combination of theoretical research. According to the characteristics of barren grassland in Tang County, the evaluation indexes of natural suitability and engineering suitability were selected, and the suitability of barren grassland for agricultural development was evaluated and graded. A classification system for the utilization of barren grassland suitable for cultivation is constructed, the required engineering types are explored to eliminate the main limiting factors, and the utilization types are matched with the engineering combination types. The barren grassland suitable for cultivation in the study area can be divided into 37 types, which can match eight engineering combinations. This study proposes a systematic method for the identification, classification, rating, and engineering matching for arable land reserve resources. The study can provide the basis for the effective utilization and accurate development of land resources. Full article
Show Figures

Figure 1

19 pages, 7952 KB  
Article
Dynamic Behavior of Galloping Micro Energy Harvester with the Elliptical Bluff Body Using CFD Simulation
by Ali Karimzadeh, Masoud Akbari, Reza Roohi and Mohammad Javad Amiri
Sustainability 2023, 15(16), 12187; https://doi.org/10.3390/su151612187 - 9 Aug 2023
Cited by 7 | Viewed by 2025
Abstract
Energy extraction from flow-induced oscillations based on piezoelectric structures has recently been tackled by several researchers. This paper presents a study of the dynamic behavior analysis and parametric characteristics of a galloping piezoelectric micro energy harvester (GPEH) applied to self-powered micro-electro-mechanical systems (MEMS). [...] Read more.
Energy extraction from flow-induced oscillations based on piezoelectric structures has recently been tackled by several researchers. This paper presents a study of the dynamic behavior analysis and parametric characteristics of a galloping piezoelectric micro energy harvester (GPEH) applied to self-powered micro-electro-mechanical systems (MEMS). The mechanical performance of a piezoelectric micro energy harvester cantilever beam with two layers of elastic silicon and piezoelectric (PZT-5A) attached to a tip elliptical cylinder is numerically simulated. Using size-dependent beam formulation on the basis of the modified couple stress theory and Gauss’ law, the coupled electro-mechanical non-linear governing equations of the energy harvester are obtained. The mode summation and Galerkin methods are used to derive the extracted power from the system. The study also models the flow field effect on the beam oscillations via CFD simulation. The effect of elliptical cylinder mass, damping ratio, beam thickness, and load resistance on the dynamic behavior and harvested power of the system is studied. Findings reveal that increasing the normalized tip mass from 0 to 0.5 and 1 increases the output power density from 0.12 to 0.2 and 0.22, respectively, and the corresponding electrical load resistance of maximum power increases from 175 to 280 kΩ and 375 kΩ, respectively. An approximately linear relation between the elliptical cylinder mass and the load resistance is observed. By increasing/decreasing the cylinder mass, the required electrical load resistance for maximum output power proportionally changes. The damping analysis shows that a higher damping ratio increases the onset velocity of galloping and decreases the extracted power. Full article
(This article belongs to the Section Energy Sustainability)
Show Figures

Figure 1

19 pages, 2047 KB  
Article
Temperature-Dependent Biology and Population Performances of the Coffee Berry Borer Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) on Artificial Diet
by Shao-Hua Wei, Liang-Jong Wang and Ming-Ying Lin
Insects 2023, 14(6), 499; https://doi.org/10.3390/insects14060499 - 29 May 2023
Viewed by 2457
Abstract
At different observation intervals of 1, 5, and 10 days during a trial period of 30 days, the mortality rates of Hypothenemus hampei were 100, 95, and 55%, and the fecundity rates were 0.55, 8.45, and 19.35 eggs/female, respectively. At temperatures of 18, [...] Read more.
At different observation intervals of 1, 5, and 10 days during a trial period of 30 days, the mortality rates of Hypothenemus hampei were 100, 95, and 55%, and the fecundity rates were 0.55, 8.45, and 19.35 eggs/female, respectively. At temperatures of 18, 21, 24, and 27 °C, the development time of the immature stage of H. hampei was significantly shortened with increasing temperature. Furthermore, the lower developmental threshold (T0) and thermal summation (K) of the immature stage were 8.91 °C and 485.44 degree-days, respectively. The greatest longevity of female and male adults reached 115.77 and 26.50 days, respectively, at 18 °C. The highest fecundity was 29.00 eggs/female at 24 °C. The population parameters of H. hampei were analyzed on the basis of the age–stage, two-sex life table theory. According to the data, the parameters were significantly affected by temperature. The highest net reproductive rate (R0) was 13.32 eggs/individual at 24 °C. The highest intrinsic rate of increase (r) and finite rate of increase (λ) were calculated as 0.0401 and 1.0409 day−1, respectively, at a temperature of 27 °C. The shortest mean generation time (T) was 51.34 days at 27 °C. Overall, we provide a discussion on comprehensive biological information regarding H. hampei, thus providing basic knowledge for further research on this pest. Full article
Show Figures

Figure 1

Back to TopTop