Hybrid Mechanism Research Articles

Development of a Novel Low-profile Robotic Exoskeleton Glove for Patients with Brachial Plexus Injuries.

This paper presents the design and development of a novel, low-profile, exoskeleton robotic glove aimed for people who suffer from brachial plexus injuries to restore their lost grasping functionality. The key idea of this new glove lies in its new finger mechanism that takes advantage of the rigid coupling hybrid mechanism (RCHM) concept. This mechanism concept couples the motions of the adjacent human finger links using rigid coupling mechanisms so that the overall mechanism motion (e.g., bending, extension, etc.) could be achieved using fewer actuators. The finger mechanism utilizes the single degree of freedom case of the RCHM that uses a rack-and-pinion mechanism as the rigid coupling mechanism. This special arrangement enables to design each finger mechanism of the glove as thin as possible while maintaining mechanical robustness simultaneously. Based on this novel finger mechanism, a two-finger low-profile robotic glove was developed. Remote center of motion mechanisms were used for the metacarpophalangeal (MCP) joints. Kinematic analysis and optimization-based kinematic synthesis were conducted to determine the design parameters of the new glove. Passive abduction/adduction joints were considered to improve the grasping flexibility. A proof-of-concept prototype was built and pinch grasping experiments of various objects were conducted. The results validated the mechanism and the mechanical design of the new robotic glove and demonstrated its functionalities and capabilities in grasping objects with various shapes and weights that are used in activities of daily living (ADLs).

Ultrafast Laser-Induced Formation of Hollow Gold Nanorods and Their Optical Properties.

Laser irradiation has been shown to be an efficient means to modify structures and shapes of plasmonic nanoparticles for tuning their properties. Thermomechanical deformations of single-crystal and penta-twinned gold nanorods by femtosecond laser irradiations have been studied by classical molecular dynamics simulations. It is demonstrated that hollow gold nanorods could be formed by femtosecond laser irradiations under certain conditions of maximum temperatures in nanorods by laser heating and cooling rates due to the extrinsic solvent. For a given maximum temperature and cooling rate, a larger cavity is induced in the irradiated single-crystal nanorod. The results also indicate that at the same cooling rate a higher threshold of maximum temperature can be required for producing the cavity in the twinned nanorod. The optical spectra of the laser-irradiated gold nanorods are calculated, and the shifts in the surface plasmon resonance peak of the nanorods are illustrated due to the thermal reshaping and the plasmon hybridization mechanism. Moreover, we show the formation of the hollow gold nanorod possessing the surface plasmon resonance peak in the second near-infrared window and a relatively small aspect ratio (∼2.8), which is highly desirable and suitable for serving as agents in biomedical imaging and photothermal therapy applications.

Optimal Achievable Transmission Capacity Scheme for Full-Duplex Multihop Wireless Networks.

Full-duplex (FD) communication has been attractive as the breakthrough technology for improving attainable spectral efficiency since the 5G mobile communication system. Previous research focused on self-interference cancellation and medium access control (MAC) protocol to realize the FD system in wireless networks. This paper proposes an optimal achievable transmission capacity (OATC) scheme for capacity optimization in the FD multihop wireless networks. In this paper, the proposed OATC scheme considers the temporal reuse for spectral efficiency and the spatial reuse with transmit power control scheme for interference mitigation and capacity optimization. OATC scheme controls the transmit power to mitigate interference and optimizes the transmission capacity, which leads to the optimal achievable network capacity. We conduct the performance evaluation through numerical simulations and compare it with the existing FD MAC protocols. The numerical simulations reveal that considering only the concurrent transmissions in the FD system does not guarantee optimal transmission capacity. Moreover, the hybrid mechanism, including the sequential transmissions, is also crucial because of the interference problem. Besides, numerical simulation validates that the proposed OATC scheme accomplishes the optimal achievable network capacity with lower interference power and higher achievable throughput than the existing MAC protocols.

Dissociative adsorption of hydrogen and methane molecules at high-angle grain boundaries of pipeline steel studied by density functional theory modeling

Pipelines provide an economic and efficient means for hydrogen transport, contributing to accelerated realization of a full-scale hydrogen economy. Dissociative adsorption of hydrogen molecules (H2) occurring on pipe steels generates hydrogen atoms (H), potentially resulting in hydrogen embrittlement of the pipelines. This is particularly important for existing pipelines transporting hydrogen in blended form with methane (CH4). In this work, a density functional theory model was developed to investigate the dissociative adsorption of H2 and CH4 at high-angle grain boundaries (HAGB), a typical type of hydrogen traps contained in steels, and the stable adsorption configurations. Results demonstrate that the dissociative adsorption of both H2 and CH4 at the HAGB is thermodynamically feasible under pipeline operating conditions. Compared with crystalline lattice sites, the HAGB possesses the most negative free energy change, a lower energy barrier and the lowest H-adsorption energy, making the HAGB, especially the quasi three-fold site, become the most stable site for hydrogen adsorption. The saturation coverage of hydrogen at HAGB is calculated to be 1.33. The iron-H bonds are formed at the HAGB by charge consumption at Fe atoms and electron accumulation at H atoms, following a so-called electron hybridization mechanism. The CH4 adsorption at HAGB affects the H2 adsorption. Without pre-adsorption of CH4, the hydrogen adsorption at the HAGB is more stable. Although an elevated CH4 partial pressure decreases the thermodynamic tendency for H2 adsorption, it cannot hinder occurrence of the H2 dissociative adsorption.

An Improved New Caledonian Crow Learning Algorithm for Global Function Optimization.

The New Caledonian crow learning algorithm (NCCLA) is a novel metaheuristic algorithm inspired by the learning behavior of New Caledonian crows learning to make tools to obtain food. However, it suffers from the problems of easily falling into local optima and insufficient convergence accuracy and convergence precision. To further improve the convergence performance of NCCLA, an improved New Caledonian crow learning algorithm (INCCLA) is proposed in this paper. By determining the parent individuals based on the cosine similarity, the juveniles are guided to search toward different ranges to maintain the population diversity; a novel hybrid mechanism of complete and incomplete learning is proposed to balance the exploration and exploitation capabilities of the algorithm; the update strategy of juveniles and parent individuals is improved to enhance the convergence speed and precision of the algorithm. The test results of the CEC2013 and CEC2020 test suites show that, compared with the original NCCLA algorithm and four of the best metaheuristics to date, INCCLA has significant advantages in terms of convergence speed, convergence precision, and stability.

Scientific Library Between Open and Corporate Science

The concept of Open science comes into conflict with the established practice of commercializing the results of research and development work. Commercialization of scientific achievements is both a way to attract funding and a deterrent to intensify the exchange of knowledge and the pace of innovation, especially in basic research. The principles of Open science, providing the ability to widely use and reuse the same data, comparing different approaches and accelerating the development of new research methods, make patenting applied developments much more difficult due to leveling the novelty of inventions in publications and open research data. The purpose of the article is to suggest the possibilities for scientific library to participate in the processes of production, exchange and dissemination of information and knowledge within the framework of the movement of science from the binary system “corporate science vs open science” to hybrid mechanisms of work. Such participation is based on the existing practices of the Centers for Legal and Technical Information and the efforts of scientific library to create an open scientific infrastructure. It involves the expansion of ongoing practices, taking into account the proposed by hybrid science differentiation of Open access to fundamental research and patenting applied developments. Thus, these opportunities are necessary for further modeling the place of scientific library in the ecosystem of open science.

Ultra-facile fabrication of oxygen vacancy-laden catalyst for peroxymonosulfate activation to degrade organic pollutant in water: Performance and mechanism

Oxygen vacancy (OV) defect engineering is high-profile for catalyst intensification, but remains in bench scale due to high cost and complicacy. Herein, for the scale- and performance-oriented defect engineering, a highly predigested mechanochemical paradigm was firstly conceived to convert spent Fe-based foodstuff deoxidizers (SFD) into mechanochemistry-derived catalysts (MSFD) via temporary grinding process. The physicochemical properties of MSFD were systematically characterized along with justifying dual-channel formation of OVs, which involved the actions of mechanical energy and reductive carbon components. With swift cycle of ≡Fe(II)/≡Fe(III) redox couple assisted by electron-rich OVs, MSFD could efficiently activate peroxymonosulfate (PMS) for contaminant elimination and bacteria inactivation in water. Hybrid mechanisms were further unveiled in which the radicals were predominant for decontamination, while the aqueous high-valent iron-oxo species played the peripheral role. The electron transfer between ≡Fe and PMS was mediated by the bridging OVs via donor-bridge-acceptor pathway, accounting for the absence of surface high-valent iron-oxo species generated through heterolytic O–O bond cleavage and atom transfer. This work furnishes a generalizable pattern for fabricating cost-effective oxygen-defective materials and profound outlooks into radical and nonradical regimes of persulfate activation.

Ultrawideband RCS Reduction Metasurface Based on Hybrid Mechanism of Absorption and Phase Cancellation

In this article, an ultrawideband radar scattering cross-sectional (RCS) reduction metasurface is proposed combining with absorption and phase cancellation mechanisms. A two-lossy-layer absorber is designed first, which is responsible for low-frequency RCS reduction from 1.3 to 13 GHz (163.6%). The equivalent circuit of the proposed absorber is extracted, proving that the wideband characteristic is due to the occurrence of multiple resonant points. To further improve the RCS reduction bandwidth, the absorber unit cells are arranged with three different heights. The proposed metasurface consists of 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 lattice and each lattice has <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> 5 absorber unit cells. The reflection phase cancellation can be achieved owing to the wave path difference by introducing a certain height difference among subregions. Resultantly, high-frequency RCS reduction from 13 to 40 GHz can be realized since the backward scattering can be canceled effectively. Finally, an extraordinary ultrawideband RCS reduction from 1.5 to 40 GHz (185.5%) can be acquired successfully. A prototype with the thickness of 0.104 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{L}$ </tex-math></inline-formula> (the wavelength of the lowest working frequency) is fabricated and measured for demonstration. The measured results prove that the proposed design has numerous advantages including minimization, ultrawideband RCS reduction, wide angle stability, and polarization insensitivity.

Design, Assessment, and Trajectory Control of a Novel Decoupled Robotic Nanomanipulator

To avoid the problems of low bandwidth or complex structure brought by conventional serial and parallel mechanisms, a novel decoupled robotic nanomanipulator (DRNM) with a hybrid configuration is conceived in this article to enable fast nanoscale manipulation. The proposed DRNM employs a new hybrid compliant structure to actuate the terminal platform and decouple the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -axial motions. The unique hybrid mechanism is devised using two H-shaped parallelogram flexures that are assembled in a serial manner and actuated in a parallel manner, bringing in the merits of a flexible terminal platform, compact structure, good decoupling, and wide bandwidth in working directions. To enhance the dynamic positioning performance of the proposed DRNM, a run-to-run-position-forward-based integral controller that can handle the hysteresis nonlinearity of the piezoelectric actuator with adaptive zero-point parameter is further designed. The DRNM prototype is tested having an in-plane resonant frequency of 2005 Hz and a cross coupling of 0.88%. While tracking a circular trajectory with a diameter of 3 µm at a frequency of 20 Hz, the DRNM exhibits a maximum filtered tracking error of 4.3 nm.

Kinematic Compatible Design and Analysis of a Back Exoskeleton via a Hyper Redundant Hybrid Mechanism

Back exoskeletons can reduce low-back pain and injury for workers engaged in manual handling operations. However, conventional back exoskeletons are incompatible with human trunk kinematics, arousing uncomfortable human-exoskeleton interaction and limiting natural human movement. This article proposes a novel back exoskeleton design to solve this problem. A hyper redundant hybrid mechanism is synthesized as the exoskeleton mechanism to be compatible with the multi-DOF anatomy of the human spine. We establish the kinematic model of the coupled human-exoskeleton system and analyze the kinematic incompatibility problem. The movement of the human back is characterized by a multi-joint lumbar spine combined with a rigid thoracic spine. The proposed back exoskeleton is composed sequentially of five six-DOF passive parallel mechanisms with one cable actuation, generating active assistance in the sagittal plane and passive assistance in the coronal and transverse planes. The kinetics of the coupled human-exoskeleton system is analyzed to show effective assistance. Experimental tests on kinematic compatibility are finally implemented to demonstrate that the proposed exoskeleton allows the wearer to perform natural movements in all directions with large ranges of motion.

Hard carbon with an “adsorption-intercalation/filling” behavior for selective deionization of lithium ions

Lithium extraction from seawater/brine to enrich the available global lithium resources is key to the development of energy storage and water desalination. Understanding the Li+ extraction mechanism in hard carbon has been a topic of debate because of its complex structure. In this work, polyimide-based carbon microsphere (PCMs) organized by ultralong nanowires was fabricated for the first time by solvent polarity induced interface self-assembly strategy. Examined as the electrode, the assembled device delivers a high Li+ extraction capacity of ~34.55 mg g−1 in LiCl solution and highly selective rapid transport in simulated Qarhan Salt Lake old brine, which is very competitive among the reported data. It is demonstrated that the Li+ ion extraction behavior in PCMs is an “adsorption-intercalation/filling” hybrid mechanism, similar to that of in batteries system. The simulation calculations further reveal that specific adsorbed sites and confined channels in PCMs dominate the Li+ ion-selective permeation behavior. This work provides a solvent polarity induced interface self-assembly strategy to develop polyimide-based hard carbon for electrochemical desalination and underlies the Li+ ion extraction mechanism, offering a general hard carbon design concept.

Orbital-selective Mott and Peierls transition in HxVO2

Materials displaying metal-insulator transitions (MITs) as a function of external parameters such as temperature, pressure, or composition are most intriguing from the fundamental point of view and also hold high promise for applications. Vanadium dioxide (VO2) is one of the most prominent examples of MIT having prospective applications ranging from intelligent coatings, infrared sensing, or imaging, to Mott memory and neuromorphic devices. The key aspects conditioning possible applications are the controllability and reversibility of the transition. Here we present an intriguing MIT in hydrogenated vanadium dioxide, HxVO2. The transition relies on an increase of the electron occupancy through hydrogenation on the transition metal vanadium, driving the system insulating by a hybrid of two distinct MIT mechanisms. The insulating phase observed in HVO2 with a nominal d2 electronic configuration contrasts with other rutile d2 systems, most of which are metallic. Using spectroscopic tools and state-of-the-art many-body electronic structure calculations, our investigation reveals a correlation-enhanced Peierls and a Mott transition taking place in an orbital-selective manner cooperate to stabilize an insulating phase. The identification of the hybrid mechanism for MIT controlled by hydrogenation opens the way to radically design strategies for future correlated oxide devices by controlling phase reversibly while maintaining high crystallinity.

360° Retail Business Analytics by Adopting Hybrid Machine Learning and a Business Intelligence Approach

Business owners and managers need strategic information to plan and execute their decisions regarding business operations. They work in a cyclic plan of execution and evaluation. In order to run this cycle smoothly, they need a mechanism that should access the entire business performance. The sole purpose of this study is to assist them through applied research framework-based analysis to obtain effective results. The backbone of the purposed framework is a hybrid mechanism that comprises business intelligence (BI) and machine learning (ML) to support 360-degree organization-wide analysis. BI modeling gives descriptive and diagnostic analysis via interactive reports with quick ad hoc analysis which can be performed by executives and managers. ML modeling predicts the performance and highlights the potential customers, products, and time intervals. The whole mechanism is resource-efficient and automated once it binds with the operational data pipeline and presented results in a highly efficient manner. Data analysis is far more efficient when it is applied to the right data at the right time and presents the insights to the right stakeholders in a friendly, usable environment. The results are beneficial to viewing the past, current, and future performance with self-explanatory graphical interpretation. In the proposed system, a clear performance view is possible by utilizing the sales transaction data. By exploring the hidden patterns of sales facts, the impact of the business dimensions is evaluated and presented on a dynamically filtered dashboard.

Reinforced securing of data leakage in Mobile Ad hoc Network (MANET) by hybrid mechanism of identity based encryption (IBE)

In Mobile Ad hoc Network (MANET), private data leakage that involves user’s private keys may become a threat to the computing systems security. It is essential that usual requirement of traditional cryptographic patterns or mechanisms have been performed for enduring several leakage attacks. However, the attacker can track and crack the cryptographic security due to the performance of continuous leakage attacks, which assist in introducing leakage resilience cryptography. But, still there are certain issues such as data loss, data failure system, data affecting and system break that are not yet resolved. As a result, various bounded-leakage models have been created for Identity Based Encryption (IBE) constructions that fail to fulfill their stated security under continuous-leakage assaults. This paper has introduced a hybrid mechanism of security to resolve the above listed issues by focusing in avoiding continuous leakage resilient through modified IBE schemes using Adaptive Chosen Cipher-text Attacks (ACCA) with Elliptical Curve Digital Signature Algorithm (ECDSA).

A Two-Phase Hybrid Trading of Green Certificate under Renewables Portfolio Standards in Community of Active Energy Agents

The future distribution network is a community involving numerous active energy agents (AEAs) and a local operator. Each AEA is obligated to meet the renewables portfolio standards (RPS) with enough green certificates (GCs), which can be obtained from renewable energy consumption or from GC trading. This paper concentrates on the GC trading in AEA community and proposes a two-phase hybrid mechanism, which combines the peer-to-peer (P2P) phase and the centralized phase. In Phase 1, GCs are traded among AEAs in P2P manner. All AEAs are classified into two types: naïve and sophisticated, each of which has the specific preference in GC trading. Additionally, each AEA finds trading partners by adopting multi-option-based matching. In Phase 2, the remaining GCs are traded between AEAs and the local operator. Numeric studies are performed on a 30-AEA community in three different market scenarios: globally balanced, undersupplied, and oversupplied. Simulation results indicate the optimality of bi-option, verify the effectiveness of the hybrid trading, and reveal the economic advantages over the sole centralized counterpart. The impact of AEA type is also discussed on both updating quotation and concluding deals.

Heat Generation and Thermal Radiation Impacts on Flow of Magnetic Eyring–Powell Hybrid Nanofluid in a Porous Medium

The paper presents the flow of mixed convection boundary layer for Eyring–Powell hybrid nanofluid over a perpendicular plate with changeable temperature and velocity profile. The nondimensional modified controlling equations in non-similar kind are resolved by utilizing hybrid mechanism: local non-similarity procedure in synchronism with RKF45 with the mechanism of shooting. The gained outcomes are offered properly by plots and discussed for different values of governing parameters. It is found that the transport of heat is diminished by increasing the magnetic field and permeability of porous medium. Furthermore, as a thermal radiation and heat generation improved, the heat transfer increased. This study gets enormous applications in industries of glass and polymer, in the field of heat exchangers styling, cooling operations of metallic plates, plastic sheets ejaculation, etc.

Dynamic hybrid mechanism-based differential evolution algorithm and its application

In order to effectively schedule railway train delay, an adaptive cooperative co-evolutionary differential evolution with dynamic hybrid mechanism of the quantum evolutionary algorithm and genetic algorithm, named QGDECC is designed in this paper. In the QGDECC, the quantum variable decomposition strategy is designed by utilizing qubit string to decompose variables adaptively according to the coevolution performance. Then the increment mutation method is proposed to improve the convergence speed which make full use of searched evolution information. Besides, the parameter adaptive strategy is deeply explored for strengthening the robust of the algorithm. The QGDECC with global search capability is employed to realize a railway train delay scheduling method for effectively eliminating the impact of train delay. Finally, several benchmark functions and actual train operation data are selected to verify the optimization performance of QGDECC. The experimental results show that QGDECC has higher adaptability, faster convergence speed and accuracy. The train delay scheduling method can effectively eliminate the impact of delay on the railway network, and minimize the gap between the rescheduled train schedule and the original train schedule.

Security Enhancement by Identifying Attacks Using Machine Learning for 5G Network

Need of security enhancement for 5G network has been increased in last decade. Data transmitted over network need to be secure from external attacks. Thus there is need to enhance the security during data transmission over 5G network. There remains different security system that focus on identification of attacks. In order to identify attack different machine learning mechanism are considered. But the issue with existing research work is limited security and performance issue. There remains need to enhance security of 5G network. To achieve this objective hybrid mechanism are introduced. Different treats such as Denial-of-Service, Denial-of-Detection, Unfair use or resources are classified using enhanced machine learning approach. Proposed work has make use of LSTM model to improve accuracy during decision making and classification of attack of 5G network. Research work is considering accuracy parameters such as Recall, precision and F-Score to assure the reliability of proposed model. Simulation results conclude that proposed model is providing better accuracy as compared to conventional model.

Coexistence and Coupling of Spin-Induced Ferroelectricity and Ferromagnetism in Perovskites.

Spin-induced ferroelectricity usually does not occur in perovskites with simple collinear magnetic structures. Here, we demonstrate that in even-layer perovskite systems, some common distortion modes involving octahedral rotation and Jahn-Teller distortion can break the inversion symmetry, allowing the emergence of spin-dependent out-of-plane polarization in a simple magnetic structure. Such spin-induced ferroelectricity is very common in double-perovskite systems and can coexist with ferromagnetism or ferrimagnetism above room temperature. We explain its origin by modifying the spin-dependent p-d hybridization mechanism. Our Letter provides a universal design for two-dimensional multiferroics and enables the control of polarization by means of a magnetic field.

Defect seeded remote epitaxy of GaAs films on graphene

Remote epitaxy is an emerging materials synthesis technique which employs a 2D interface layer, often graphene, to enable the epitaxial deposition of low defect single crystal films while restricting bonding between the growth layer and the underlying substrate. This allows for the subsequent release of the epitaxial film for integration with other systems and reuse of growth substrates. This approach is applicable to material systems with an ionic component to their bonding, making it notably appealing for III–V alloys, which are a technologically important family of materials. Chemical vapour deposition growth of graphene and wet transfer to a III–V substrate with a polymer handle is a potentially scalable and low cost approach to producing the required growth surface for remote epitaxy of these materials, however, the presence of water promotes the formation of a III–V oxide layer, which degrades the quality of subsequently grown epitaxial films. This work demonstrates the use of an argon ion beam for the controlled introduction of defects in a monolayer graphene interface layer to enable the growth of a single crystal GaAs film by molecular beam epitaxy, despite the presence of a native oxide at the substrate/graphene interface. A hybrid mechanism of defect seeded lateral overgrowth with remote epitaxy contributing the coalescence of the film is indicated. The exfoliation of the GaAs films reveals the presence of defect seeded nucleation sites, highlighting the need to balance the benefits of defect seeding on crystal quality against the requirement for subsequent exfoliation of the film, for future large area development of this approach.