•The state-of-the-art design and modeling approaches of constant-force mechanisms are surveyed.•Both rigid-body and fully-compliant constant-force mechanisms are reviewed.•working principles, design ...methods, modeling approaches, pros and cons are introduced.•Four modeling methods and five compliant constant-force mechanism designs are outlined.•It is helpful to those engaged in constant-force mechanism area to know the recent state and research tendency.
Constant-force mechanisms (CFMs) have become a hot research topic in recent years. Unlike conventional force control technology by using force sensor and controller, which leads to a complicated algorithm design and higher cost, the CFMs can provide a near constant force output by using the property of mechanical structure. Hence, the CFMs are widely used in overload protection, biomedical application, and robot end-effectors for providing a friendly interaction with the environment as well as micromanipulation for protecting the micro-objects from being damaged. This paper presents a survey of the state-of-the-art design and modeling approaches for constant-force mechanisms. According to the working principles, the CFMs are classified into five kinds of conventional rigid-link constant-force mechanisms and five kinds of fully compliant constant-force mechanisms. In addition, the comparisons between different types of the CFMs are discussed. In particular, compliant constant-force mechanisms emerge as promising devices owing to the specific advantages. Four modeling methods and five types of compliant constant-force mechanism designs are introduced in detail. The presented overview is helpful to those engaged in constant-force mechanism area to know the recent state and research tendency.
We provide a revelation principle for a class of single-agent dynamic mechanism design settings in which the agent’s private information evolves stochastically over time and the designer can only ...commit to short-term mechanisms. We restrict attention to Markov environments, in which (i) the agent’s type in period t+1 depends only on her period-t type and the period-t allocation, (ii) the designer’s and the agent’s payoffs are time-separable, and (iii) their period-t payoffs depend only on period-t type and the period-t allocation. We show all equilibrium payoffs can be attained with the designer using flow direct Blackwell mechanisms, which consist of a mapping from the agent’s current type report to posterior beliefs about the current type, and a mapping from these beliefs to allocations. Furthermore, all equilibrium payoffs can be attained with strategies in which the agent participates and truthfully reports her type, and the beliefs that result from the mechanism correspond to the designer’s equilibrium beliefs. This result greatly simplifies the search of optimal dynamic and sequentially rational mechanisms in dynamic mechanism design problems, which include dynamic Mirrlees and social insurance models.
Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are ...known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment) or negative effects (e.g., autotoxicity, soil sickness, or biological invasion). To ensure sustainable agricultural development, it is important to exploit cultivation systems that take advantage of the stimulatory/inhibitory influence of allelopathic plants to regulate plant growth and development and to avoid allelopathic autotoxicity. Allelochemicals can potentially be used as growth regulators, herbicides, insecticides, and antimicrobial crop protection products. Here, we reviewed the plant allelopathy management practices applied in agriculture and the underlying allelopathic mechanisms described in the literature. The major points addressed are as follows: (1) Description of management practices related to allelopathy and allelochemicals in agriculture. (2) Discussion of the progress regarding the mode of action of allelochemicals and the physiological mechanisms of allelopathy, consisting of the influence on cell micro- and ultra-structure, cell division and elongation, membrane permeability, oxidative and antioxidant systems, growth regulation systems, respiration, enzyme synthesis and metabolism, photosynthesis, mineral ion uptake, protein and nucleic acid synthesis. (3) Evaluation of the effect of ecological mechanisms exerted by allelopathy on microorganisms and the ecological environment. (4) Discussion of existing problems and proposal for future research directions in this field to provide a useful reference for future studies on plant allelopathy.
MEDER 2018, the IFToMM International Symposium on Mechanism Design for Robotics, was the fourth event in a series that was started in 2010 as a specific conference activity on mechanisms for robots. ...The aim of the MEDER Symposium is to bring researchers, industry professionals, and students together from a broad range of disciplines dealing with mechanisms for robots, in an intimate, collegial, and stimulating environment. In the 2018 MEDER event, we received significant attention regarding this initiative, as can be seen by the fact that the Proceedings contain contributions by authors from all around the world.The Proceedings of the MEDER 2018 Symposium have been published within the Springer book series on MMS, and the book contains 52 papers that have been selected after review for oral presentation. These papers cover several aspects of the wide field of robotics dealing with mechanism aspects in theory, design, numerical evaluations, and applications.This Special Issue of Robotics (https://www.mdpi.com/journal/robotics/special_issues/MDR) has been obtained as a result of a second review process and selection, but all the papers that have been accepted for MEDER 2018 are of very good quality with interesting contents that are suitable for journal publication, and the selection process has been difficult.
•The Seven mechanisms of OER proposed recently have been summarized.•Some unique insights into the development of OER mechanisms have been provided.•More exploratory directions have been provided for ...the development of OER.
The oxygen evolution reaction (OER) is a crucial step in the utilization and storage of sustainable energy. However, due to its multi-step and multi-electron transfer process, the kinetics of OER are extremely slow, limiting the development of these projects. Additionally, OER involves various reaction intermediates, which pose challenges for researchers to understand the mechanism of OER. Currently, some work is still focused on the traditional adsorbate evolution mechanism, which is not advanced and comprehensive enough, theoretically limiting the potential of these studies. Recent reports have proposed new mechanisms, and we have conducted a brief analysis of how they conceptualize the new mechanisms, demonstrate their feasibility, describe their operation, and detect them. We also put forward some relevant conclusions and prospects, hoping to provide more research perspectives and ideas for the development of OER.
The galvanostatic lithiation/sodiation voltage profiles of hard carbon anodes are simple, with a sloping drop followed by a plateau. However, a precise understanding of the corresponding redox sites ...and storage mechanisms is still elusive, which hinders further development in commercial applications. Here, a comprehensive comparison of the lithium‐ and sodium‐ion storage behaviors of hard carbon is conducted, yielding the following key findings: 1) the sloping voltage section is presented by the lithium‐ion intercalation in the graphitic lattices of hard carbons, whereas it mainly arises from the chemisorption of sodium ions on their inner surfaces constituting closed pores, even if the graphitic lattices are unoccupied; 2) the redox sites for the plateau capacities are the same as those for the closed pores regardless of the alkali ions; 3) the sodiation plateau capacities are mostly determined by the volume of the available closed pore, whereas the lithiation plateau capacities are primarily affected by the intercalation propensity; and 4) the intercalation preference and the plateau capacity have an inverse correlation. These findings from extensive characterizations and theoretical investigations provide a relatively clear elucidation of the electrochemical footprint of hard carbon anodes in relation to the redox mechanisms and storage sites for lithium and sodium ions, thereby providing a more rational design strategy for constructing better hard carbon anodes.
A comprehensive comparison of the lithium‐ and sodium‐ion storage behaviors of hard carbon is conducted, yielding the key findings: the sloping voltage section is presented by the lithium‐ion intercalation in the graphitic lattices of hard carbons, whereas it mainly arises from the chemisorption of sodium ions. The intercalation preference and the plateau capacity have an inverse correlation.
The main purpose of current study is accurate prediction of NOx emissions from diesel engines considering in-cylinder ion current. To reach this goal, a validated thermodynamic multi-zone model was ...used. A modified chemical kinetics mechanism of diesel fuel oxidation was used too. A chemical kinetics mechanism of NOX formation including 103 reactions was added to the main mechanism. A set of ions and ionic reactions was added to the developed chemical kinetics mechanism and finally a modified chemical kinetics mechanism with 445 reactions and 100 species was formed. The developed mechanism was coupled to the multi-zone model and a diesel engine was simulated. The importance of Zeldovich mechanism, prompt mechanism, N2O mechanism and NNH mechanism were investigated. The progress rates of reactions were calculated and important reactions were identified. The results show that the oxygenated ions, NO+, O+ and O2+, has more effects on NO production than other ions. The prompt mechanism plays an important role in predicting the ion current inside the chamber. Because this mechanism has reactions that can lead to CH production. The CH radicals produced by this mechanism can be employed by basic ionic reactions and lead to ion production. The results show that using NOx related ionic reactions results in accurate prediction of engine exhaust NOx.
This paper has been recommended for acceptance by Pavlos Kassomenos. Display omitted
•NOx formation in diesel engines is simulated using ionic reactions.•Using NOx related ionic reactions results in accurate prediction of exhaust NOx.•CH plays an important role in initiating ionic reactions.•The oxygenated ions, NO+, O+ and O2+, has significant effects on NO production.
PDF
