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Transport in Nanoporous Media

Weiyao Zhu,Bin Pan,Zhen Chen,Wengang Bu,Qipeng Ma,Kai Liu,Ming Yue

Engineering 2024, Volume 32, Issue 1, Pages 139-152 doi: 10.1016/j.eng.2023.05.014

Abstract:

Fluid flow at nanoscale is closely related to many areas in nature and technology, e.g., unconventionalAt nanoscale, interfacial forces dominate over bulk forces, and nonlinear effects are important, whichpast decades, a series of experiments, theory and simulations have been performed to investigate fluid flowsystematically review experimental, theoretical and simulation works on single- and multi- phases fluid flowThese insights will promote the significant development of nonlinear flow physics at nanoscale and will

Keywords： Transport in nanoporous media Multi-phase fluid dynamics Nonlinear flow mechanisms Nonlinear flow conservation

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A brief review on nonlinear modeling methods and applications of compliant mechanisms

Guangbo HAO,Jingjun YU,Haiyang LI

Frontiers of Mechanical Engineering 2016, Volume 11, Issue 2, Pages 119-128 doi: 10.1007/s11465-016-0387-9

Abstract:

Compliant mechanisms (CMs) have become one of the most popular research themes in mechanisms and roboticsThis paper aims to provide a brief systematic review on the advances of nonlinear static modeling approaches

Keywords： compliant mechanisms modelling nonlinearity applications review

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A review of recent experimental investigations and theoretical analyses for pulsating heat pipes

Xin TANG, Lili SHA, Hua ZHANG, Yonglin JU

Frontiers in Energy 2013, Volume 7, Issue 2, Pages 161-173 doi: 10.1007/s11708-013-0250-1

Abstract: is found that the state-of-the-art experimental investigations on the PHPs are mainly focused on the flowthat the present theoretical analyses of the PHP are restricted by further development of two-phase flow

Keywords： pulsating heat pipe (PHP) flow visualization nanofluids nonlinear analysis

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FOOD SYSTEMS TRANSFORMATION: CONCEPTS, MECHANISMS AND PRACTICES

Frontiers of Agricultural Science and Engineering 2023, Volume 10, Issue 1, Pages 1-3 doi: 10.15302/J-FASE-2023491

Abstract: FOOD SYSTEMS TRANSFORMATION: CONCEPTS, MECHANISMS AND PRACTICES

Keywords： TRANSFORMATION SYSTEMS FOOD CONCEPTS MECHANISMS

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Gripping mechanisms in current wood harvesting machines

D. GOUBET, J. C. FAUROUX, G. GOGU

Frontiers of Mechanical Engineering 2013, Volume 8, Issue 1, Pages 42-61 doi: 10.1007/s11465-013-0358-3

Abstract:

This paper focuses on the structural synthesis of gripping mechanisms used in the mechanization ofThis function is performed with several typical mechanisms which are listed and described in this articleThis study distinguishes two kinds of planar gripping mechanisms mainly used in opening and closing theTwo planar and one spatial existing mechanisms are described.Nine kinematic diagrams of spatial parallel mechanisms are provided.

Keywords： structural synthesis parallel mechanisms gripping mechanisms wood harvesting harvesting head

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Recent development on innovation design of reconfigurable mechanisms in China

Wuxiang ZHANG, Shengnan LU, Xilun DING

Frontiers of Mechanical Engineering 2019, Volume 14, Issue 1, Pages 15-20 doi: 10.1007/s11465-018-0517-7

Abstract: Reconfigurable mechanisms can deliberately reconfigure themselves by rearranging the connectivity ofMetamorphic and origami-derived mechanisms are two kinds of typical reconfigurable mechanisms, whichhave attracted increasing attention in the field of mechanisms since they were proposed.This paper presents an overview of recent developments in innovation design of reconfigurable mechanismsin China, including metamorphic and origami mechanisms and their typical applications.

Keywords： innovation design reconfigurable mechanisms metamorphic mechanisms origami-derived mechanisms development

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CROP DIVERSITY AND SUSTAINABLE AGRICULTURE: MECHANISMS, DESIGNS AND APPLICATIONS

Frontiers of Agricultural Science and Engineering 2021, Volume 8, Issue 3, Pages 359-361 doi: 10.15302/J-FASE -2021417

Abstract:

Intensive monoculture agriculture has contributed greatly to global food supply over many decades, but the excessive use of agricultural chemicals (fertilizers, herbicides and pesticides) and intensive cultivation systems has resulted in negative side effects, such as soil erosion, soil degradation, and non-point source pollution^{^[1]}. To many observers, agriculture looms as a major global threat to nature conservation and biodiversity. As noted in the Global Biodiversity Outlook 4^{^[2]}, the drivers associated with food systems and agriculture account for around 70% and 50% of the projected losses by 2050 of terrestrial and freshwater biodiversity, respectively^{^[3]}.

In addition, agricultural development and modernization of agriculture has led to a decline in the total number of plant species upon which humans depend for food^{^[4]}. Currently, fewer than 200 of some 6000 plant species grown for food contribute substantially to global food output, and only nine species account for 67% of total crop production^{^[3]}. The global crop diversity has declined in past decades.

Crop species diversity at a national scale was identified as one of the most important factors that stabilize grain production at a national level^{^[5]}. A group of long-term field experiments demonstrated that crop diversity also stabilizes temporal grain productivity at field level^{^[6]}. Therefore, maintaining crop diversity at both national and field levels is of considerable importance for food security at national and global scales.

Crop diversity includes temporal (crop rotation) and spatial diversity (e.g., intercropping, agroforestry, cultivar mixtures and cover crops) at field scale. Compared to intensive monocultures, diversified cropping systems provide additional options to support multiple ecosystem functions. For instance, crop diversity may increase above- and belowground biodiversity, improve yield stability, reduce pest and disease damage, reduce uses of chemicals, increase the efficiency of the use land, light water and nutrient resources, and enhance stress resilience in agricultural systems.

To highlight advances in research and use of crop diversity, from developing and developed countries, we have prepared this special issue on “Crop Diversity and Sustainable Agriculture” for Frontiers of Agricultural Sciences and Engineering, mainly focusing on intercropping.

Intercropping, growing at least two crops at the same time as a mixture, for example, in alternate rows or strips, is one effective pathway for increasing crop diversity at the field scale. Over recent decades, there have been substantial advances in terms of understanding of processes between intercropped species and applications in practice. There are 10 articles in this special issue including letters, opinions, review and research articles with contributions from Belgium, China, Denmark, France, Germany, Greece, Italy, the Netherlands, Spain, Switzerlands, UK, and Mexico etc.

The contributors are internationally-active scientists and agronomists contributing to intercropping research and extension. For example, Antoine Messean is coordinator of the EU H2020 Research project DiverIMPACTS “Diversification through rotation, intercropping, multiple cropping, promoted with actors and value chains towards sustainability”. Eric Justes is coordinator of the EU H2020 Research project ReMIX “Redesigning European cropping systems based on species mixtures”. Maria Finckh has worked on crop cultivar mixture and organic agriculture over many years. Henrik Hauggaard-Nielsen has outstanding expertise in intercropping research and applications, moving from detailed studies on species interactions in intercropping to working with farmers and other stakeholders to make intercropping work in practical farming. In addition to these established scientists, young scientists who have taken an interest in intercropping also contribute to the special issue, including Wen-Feng Cong, Yixiang Liu, Qi Wang, Hao Yang and others.

The first contribution to this special issue addresses how to design cropping systems to reach crop diversification, with Wen-Feng Cong and coworkers ( https://doi.org/10.15302/J-FASE-2021392) considering that it is necessary to optimize existing and/or design novel cropping systems based on farming practices and ecological principles, and to strengthen targeted ecosystem services to achieve identified objectives. In addition, the design should consider regional characteristics with the concurrent objectives of safe, nutritious food production and environmental protection.

The benefits of crop diversification have been demonstrated in many studies. Wen-Feng Cong and coworkers describe the benefits of crop diversification at three scales: field, farm, and landscape. Hao Yang and coauthors reviewed the multiple functions of intercropping. Intercropping enhances crop productivity and its stability, it promotes efficient use of resources and saves mineral fertilizer, controls pests and diseases of crops and reduces the use of pesticides. It mitigates climate change by sequestering carbon in soil, reduces non-point source pollution, and increases above- and belowground biodiversity of other taxa at field scale ( https://doi.org/10.15302/J-FASE-2021398).

Eric Justes and coworkers proposed the “4C” framework to help understand the role of species interactions in intercropping ( https://doi.org/10.15302/J-FASE-2021414). The four components are competition, complementary, cooperation (facilitation) and compensation, which work often simultaneously in intercropping. Hao Yang and coworkers used the concept of diversity effect from ecology to understand the contribution of complementarity and selection effects to enhanced productivity in intercropping. The complementarity effect consists of interspecific facilitation and niche differentiation between crop species, whereas the selection effect is mainly derived from competitive processes between species such that one species dominates the other ( https://doi.org/10.15302/J-FASE-2021398). Also, Luis Garcia-Barrios and Yanus A. Dechnik-Vazquez dissected the ecological concept of the complementarity and selection effects to develop a relative multicrop resistance index to analyze the relation between higher multicrop yield and land use efficiency and the different ecological causes of overyielding under two contrasting water stress regimes ( https://doi.org/10.15302/J-FASE-2021412).

Odette Denise Weedon and Maria Renate Finckh found that composite cross populations, with different disease susceptibilities of three winter wheat cultivars, were moderately resistant to brown rust and even to the newly emerged stripe rust races prevalent in Europe since 2011, but performance varied between standard and organic management contexts ( https://doi.org/10.15302/J-FASE-2021394).

Comparing the performance of intercrops and sole crops is critical to make a sound evaluation of the benefits of intercropping and assess interactions between species choice, intercrop design, intercrop management and factors related to the production situation and pedoclimatic context. Wopke van der Werf and coworkers review some of the metrics that could be used in the quantitative synthesis of literature data on intercropping ( https://doi.org/10.15302/J-FASE-2021413).

Interspecific interactions provide some of the advantages of intercropping, and can be divided into above- and belowground interactions. Aboveground interactions can include light and space competition, which is influenced by crop species traits. Root exudates are also important in interspecific interactions between intercropped or rotated species. Qi Wang and coworkers estimated the light interception of growth stage of maize-peanut intercropping and corresponding monocultures, and found that intercropping has higher light interception than monoculture, and increasing plant density did not further increase light interception of intercropping ( https://doi.org/10.15302/J-FASE-2021403). Yuxin Yang and coworkers reported that the root exudates of fennel (Foeniculum vulgare) can reduce infection of tobacco by Phytophthora nicotianae via inhibiting the motility and germination of the spores of the pathogen ( https://doi.org/10.15302/J-FASE-2021399).

Focusing on the application of intercropping, Wen-Feng Cong and coworkers formulated species recommendations for different regions of China for different crop diversity patterns and crop species combinations. These authors also suggested three steps for implementing crop diversification on the North China Plain. Although there are multiple benefits of crop diversification, its extension and application are hindered by various technical, organizational, and institutional barriers along value chains, especially in Europe. Based on the findings of the European Crop Diversification Cluster projects, Antoine Messéan and coworkers suggested that there needs to be more coordination and cooperation between agrifood system stakeholders, and establish multiactor networks, toward an agroecological transition of European agriculture ( https://doi.org/10.15302/J-FASE-2021406). In addition, Henrik Hauggaard-Nielsen and coworkers report the outcomes of a workshop for participatory research to overcome the barriers to enhanced coordination and networking between stakeholders ( https://doi.org/10.15302/J-FASE-2021416).

Intercropping, though highly effective in labor-intensive agriculture, may be difficult to implement in machine-intensive, large-scale modern agriculture because appropriate large equipment is not commercially available for planting and harvesting various crop mixtures grown with strip intercropping^{^[6]}. Thus, the appropriate machinery will need to be developed for further practical application in large-scale agriculture.

As the guest editors, we thank all the authors and reviewers for their great contributions to this special issue on “Crop Diversity and Sustainable Agriculture”. We also thank the FASE editorial team for their kind supports.

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New nonlinear stiffness actuator with predefined torque‒deflection profile

Frontiers of Mechanical Engineering 2023, Volume 18, Issue 1, doi: 10.1007/s11465-022-0721-3

Abstract: A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range

Keywords： compliant actuator nonlinear stiffness actuator nonlinear spring predefined torque−deflection profile

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Mass transport mechanisms within pervaporation membranes

Yimeng Song, Fusheng Pan, Ying Li, Kaidong Quan, Zhongyi Jiang

Frontiers of Chemical Science and Engineering 2019, Volume 13, Issue 3, Pages 458-474 doi: 10.1007/s11705-018-1780-1

Abstract: Fundamental understanding of the mass transport mechanisms is crucial for the rational design of membraneinteractions between permeate molecules and membranes, this review focuses on two categories of mass transport mechanismsFurthermore, the optimal integration and evolution of different mass transport mechanisms are brieflyMaterial selection and relevant applications are highlighted under the guidance of mass transport mechanisms

Keywords： pervaporation membrane mass transport mechanisms physical mechanism chemical mechanism

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Optimal Scheduling of Variable-pressure Variable-flow Operation of Inverter-drive Pumps Connected in

Li Hongbin,Zhang Chenghui,Song Jun

Strategic Study of CAE 2001, Volume 3, Issue 9, Pages 52-57

Abstract: paper analyzes common methods for the optimal scheduling modeling problem of variable-pressure variable-flowanother method, the objective function is the square of the difference between the actual and needed flow

Keywords： optimal scheduling nonlinear bounded programming speed regulation of pumps

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Special issue: Mechanisms and robotics

Jingjun YU

Frontiers of Mechanical Engineering 2016, Volume 11, Issue 2, Pages 117-118 doi: 10.1007/s11465-016-0399-5

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Mean wind load induced incompatibility in nonlinear aeroelastic simulations of bridge spans

Zhitian ZHANG

Frontiers of Structural and Civil Engineering 2019, Volume 13, Issue 3, Pages 605-617 doi: 10.1007/s11709-018-0499-x

Abstract: Mean wind response induced incompatibility and nonlinearity in bridge aerodynamics is discussed, where the mean wind and aeroelastic loads are applied simultaneously in time domain. A kind of incompatibility is found during the simultaneous simulation of the mean wind and aeroelastic loads, which leads to incorrect mean wind structural responses. It is found that the mathematic expectations (or limiting characteristics) of the aeroelastic models are fundamental to this kind of incompatibility. In this paper, two aeroelastic models are presented and discussed, one of indicial-function-denoted (IF-denoted) and another of rational-function-denoted (RF-denoted). It is shown that, in cases of low wind speeds, the IF-denoted model reflects correctly the mean wind load properties, and results in correct mean structural responses; in contrast, the RF-denoted model leads to incorrect mean responses due to its nonphysical mean properties. At very high wind speeds, however, even the IF-denoted model can lead to significant deviation from the correct response due to steady aerodynamic nonlinearity. To solve the incompatibility at high wind speeds, a methodology of subtraction of pseudo-steady effects from the aeroelastic model is put forward in this work. Finally, with the method presented, aeroelastic nonlinearity resulted from the mean wind response is investigated at both moderate and high wind speeds.

Keywords： bridge aerodynamics nonlinear aeroelastic model Pseudo-steady mean wind loads

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General expression for linear and nonlinear time series models

Ren HUANG, Feiyun XU, Ruwen CHEN

Frontiers of Mechanical Engineering 2009, Volume 4, Issue 1, Pages 15-24 doi: 10.1007/s11465-009-0015-z

Abstract: However, some nonlinear factors are within the practical system; thus, it is difficult to fit the modelThis paper proposes a general expression for linear and nonlinear auto-regressive time series modelsexperiments show that the GNAR model can accurately approximate to the dynamic characteristics of the most nonlinear

Keywords： linear and nonlinear autoregressive model system identification time series analysis

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Evaluation of transmissibility for a class of nonlinear passive vibration isolators

Z. K. PENG, Z. Q. LANG, G. MENG

Frontiers of Mechanical Engineering 2012, Volume 7, Issue 4, Pages 401-409 doi: 10.1007/s11465-012-0349-9

Abstract: concept of Output Frequency Response Functions (OFRFs) is applied to represent the transmissibility of nonlinearcharacteristic parameters is derived for a wide class of nonlinear isolators that have nonlinear anti-symmetricdamping characteristics and a comprehensive pattern about how the nonlinear damping characteristic parametersThese conclusions are of significant importance in the analysis and design of the nonlinear vibrationisolators with nonlinear anti-symmetric damping.

Keywords： nonlinear vibration volterra series Output Frequency Response Functions (OFRFs) nonlinear damping vibration