Annular Structure Research Articles

Annular Ring UWB Wearable Textile Antenna for Telemetry and Healthcare Applications

A wearable microstrip UWB antenna employing jeans textile material as a substrate is proposed and analyzed. Two variants of conducting material comprising copper tape and copper wire of thickness of 0.1mm are utilized as patch and ground. The overall antenna volume is 50 × 50 × 1 mm3 with an impedance bandwidth of 24.13 GHz (0.87 to 25 GHz) and a peak gain of 10.93 dB at 14.80 GHz. The design comprising an annular ring structure with connecting feed at the optimized location has been analyzed and optimized using FEM based ANSYS High-Frequency Structural Simulator. The low values of Specific Absorption Rate (SAR) 1.23W/kg, 1.26W/kg, and 0.64W/kg averaged over 1-g of tissue for arm, leg, and head respectively at 2.45 GHz validate the antenna design for wearable telemetry applications. The proposed design is also analyzed under different bent radii for wearable applications. Measured results for both prototypes agree well with the simulated results.

A novel elliptical annular re-entrant auxetic honeycomb with enhanced stiffness

Auxetic structures have sparked a lot of interest due to their excellent mechanical characteristics and unusual negative Poisson's ratio influence. However, the large porosity property results in low stiffness, which limits their application scope. Current approaches to augment stiffness often result in diminished auxetic performance. Therefore, it is challenging to simultaneously enhance the auxetic, stiffness and energy absorption capacity of auxetic structures. To address this issue, this paper proposes a novel elliptical annular re-entrant honeycomb (EARE) by introducing an elliptical annular structure into a conventional re-entrant honeycomb (RE) cell, which can provide extra longitudinal support without hindering lateral deformation. The plateau stress, Poisson's ratio and energy absorption properties of the EARE are investigated by quasi-static compressive tests and finite element modeling. The results show that the EARE honeycomb has two plateau stages due to the supporting effect of the elliptical annular structure. Compared with the conventional RE honeycomb with the same wall thickness, the EARE honeycomb not only exhibits a stronger auxetic effect embodied in the Poisson's ratio reduced by 5.19%, but also has a higher average plateau stress and a higher specific energy absorption of 171.63% and 28.03%, respectively, which significantly improves the stiffness and energy absorption performance. The parameterized analysis reveals that by appropriately adjusting the geometric parameters, the stiffness, energy absorption, and auxetic effect of the EARE honeycomb can be enhanced. The research findings address the conflict between auxetic performance and honeycomb stiffness, providing new insights into the optimization of honeycomb structure design.

Mechanism of time-delay feedback control of suspension damping with an annular vibration-absorbing structure

With the aim of enhancing both the ride comfort and the safety of the vehicle, we propose a new type of suspension with an annular vibration-absorbing structure, and establish a 3-DOF 1/4 vehicle model. The structure parameters and time-delay feedback control parameters are determined by particle swarm optimization algorithms, which take the root mean values of body acceleration, suspension dynamic deflection, and tire dynamic displacement as their optimization objectives. We analyze the stability of the suspension control system to ensure the stability of the time-delay control system through the Routh-Hurwitz stability criterion, characteristic root method, and stability switching method. Then, we compare and analyze the response characteristics of conventional suspension, new suspension without time-delay feedback control, and new suspension with time-delay feedback control under simple harmonic excitation and random excitation. The results show that the new suspension with time-delay feedback control has a significant damping effect on the body under the premise of ensuring the stability of the system.

Cooperative cell–cell actin network remodeling to perform Gap junction endocytosis

BackgroundThe endocytosis of Gap junction plaques (GJP) requires cytoskeletal forces to internalize such large membranous structures. Actin, which partners the connexin proteins constituting Gap junctions and is located close to Annular Gap Junctions (AGJ), could be actively involved in this physiological process.ResultsElectron Microscopy and Light Microscopy images, associated with time-lapse analysis and 3D reconstruction, used at high resolution and enhanced using ImageJ based software analysis, revealed that: i) actin cables, originating from Donor cells, insert on the edge of GJP and contribute to their invagination, giving rise to AGJ, whereas actin cables on the Acceptor cell side of the plaque are not modified; ii) actin cables from the Donor cell are continuous with the actin network present over the entire GJP surface. These actin cables fuse at a single point distant from the plaque, which then detaches itself from the membrane, condensing to form an actin mass during the final internalization process; iii) the Acceptor cell participates in the last step of the endocytic invagination process by forming an annular actin structure known as an actin ring.ConclusionsTogether, these data suggest that the endocytosis of GJP is an example of a unique cooperative mechanism between the Donor (the traction of its actin cables) and the Acceptor cells (forming the actin ring).

Entanglement maintenance of classically pumped qubits and calibration aspects with the resonator tomography under the Stark shift effect inside a coherent resonator

We present a scheme for the investigation of entanglement of a similar qubits-pair along with the coherent resonator tomography under two-photon processes. Our discussion is focusing on the effect of the classical power amplitude along with Stark shift width and the conditions under which they have a constructive role in protecting the initial-state entanglement and the corresponding field tomography evolution. We observe that the entanglement between the qubits does maximally peak below a critical value and can be determined by suitable measurements on the resonator tomography. Interestingly, above the critical value, the tomography profile either shows an annular structure or exhibits quantumness which could be largely diminished by controlling the driving power intensity as well as the shift width. Particularly and for a detuned interaction, the critical values can be largely exceeded for sufficiently large values of the driving intensity and Stark shift, hence, more regions in the plane of parameters can be occupied by the qubits correlation. In this case, the pronounced fluctuations exhibited by entanglement dynamics due to phase variations could be highly interrupted. Additionally, preserving the field tomography showing a multi-component Schrödinger cat state via field-field detuning, robust, periodical and close to unity entanglement between the qubits could be highly possible. Moreover, in particular situations, the field tomography dynamics show the Fourier transform of the original field wave packet one-quarter period after initial, accordingly, entanglement maxima are reached frequently per a quarter period of rotation.

Dynamic characteristics and structural stability analysis of a large annular tensegrity structure with radial ribs

PurposeIn order to make the aperture of spatial deployable antenna larger, this paper proposed the study on a spatial annular tensegrity structure with 100 m large scale, which could be one of the ideal solutions to improve the dimension of the antenna. This study is aiming to figure out the dynamic characteristic of ultra-large annular tensegrity and address the problem of insufficient rigidity with local modes that many ring truss-type deployable antenna structures have faced.Design/methodology/approachThis work is carried out based on the nonlinear dynamic modelling when fully considering the effect of bending and torsion deformation of beams, as well as the pretension of cables. Additionally, the structural stability analysis based on the proposed stability criterion is also presented to evaluate the tensegrity configuration with different distribution of cable groups.FindingsThis research results verify that the modified structure with radial ribs could eliminate the effect of the local vibration mode on stiffness and is suitable to meet the requirements of the annular tensegrity structure. Additionally, the calculation results demonstrate that the structural configuration of annular tensegrity with 36 groups of cables which share the nodes with radial ribs is more appropriate to enhance the stiffness and structural stability.Originality/valueA new large annular tensegrity structure with radial ribs and tensioned cables is proposed. Based on the proposed structural configuration, the positive definiteness of the tangent stiffness matrix is carried out as the criterion of stability and the composition of the analytical expression of the tangent stiffness matrix is analyzed. Four levels of tensegrity structure stability have been carried out and the influence of the structural parameters on the stability and the rigidity has been analyzed. A scaled-down prototype is developed to verify the feasibility of the design of the hoop-column-rib configuration by the deployment and dynamic experiment.

A high-precision strain seeding spacing monitoring system based on a combined bionic strain sensor and strain peak recognition algorithm

This study has discovered a novel monitoring quantity suitable for seeding spacing monitoring, which is the strain signal generated by the seed flow through the seed discharge port during the operation of the finger-clip seed metering device. The strain sensor output a dataset of approximately 30 electrical signals for each flow of the seed pick-up clip of the finger-clip seed metering device through the seed discharge port. The number of peak points in this data set is equivalent to the number of seeds sown, enabling accurate judgment of missed seeding or reseeding. This study addressed the problem that field vibrations tend to cause displacement of seed, which in turn triggers a change in strain direction. Through a combined bionic design, a scorpion body surface V-shaped crack structure (ultrasensitive sensing function) and a spider-web annular topology (omnidirectional equalization sensing function) were selected as bionic prototypes to develop a combined bionic strain sensor (CBSS). The test results showed that the CBSS combines the functional characteristics of both bionic structures and was more suitable for seed spacing monitoring. Compared to the conventional straight-line V-shaped crack strain sensor (CSS), CBSS improved the omnidirectional sensitivity by 21.54–35.57%. To mitigate the impact of ground frequency noise in the system causing fluctuations in the CBSS output signal, a strain peak recognition algorithm (SPRA) was developed using image processing techniques and Python. The SPRA effectively removed ground frequency noise using a gray-scale erosion algorithm and accurately recognized peak points in the electrical signal dataset through the Suzuki and CEV algorithms. Results showed that the SPRA reduced monitoring errors by 20.52% compared to the conventional direct data processing method (DDPM). Based on the CBSS and SPRA, a strain seeding spacing monitoring system (S-SMS) was developed. Bench tests revealed that the parameters of the combined bionic annular crack structure (crack depth h) of the CBSS significantly affected the monitoring error of the S-SMS, with optimal performance achieved at the h value of 82 μm. Field tests demonstrated that the CBSS accurately monitored the strain signal triggered by each seed with 98.51% accuracy, while the SPRA recognized missed seeding and reseeding with 98.64% and 98.42% accuracy, respectively. Compared to the conventional photoelectric diffuse reflection seeding monitoring system (P-SMS), the S-SMS reduced seeding monitoring errors in the field by 3.51%. This research can provide a new research path for the development of seeding spacing monitoring systems.

Recovery of core annular flow structure in a horizontal T-pipe using CFD approach

Previous work about CAF through a T-pipe reported that CAF stability could not be maintained after passing the intersection. The current CFD study was expected to propose a strategy to recover the stability of CAF in a horizontal T-pipe without interrupting the flow process. A recirculation zone was detected in the area near the junction. Additional water with a certain design of insertion and water velocity is introduced at the intersection to support the recovery of CAF by suppressing fouling. This numerical work covered both qualitative evaluation of CAF consistency along the T-pipe and quantitative evaluation to analyze the attainable energy savings of the proposed strategy. From some candidates for water insertion geometries and velocities of additional water, the ducting insertion with a water velocity of 2 m/s showed a consistent CAF structure starting at about 200 mm from the intersection point to the final downstream exits. This proposed design was estimated to reduce pressure drop more than 98% compared to transportation without lubrication and 4% higher than design without additional water injection. The power reduction factor was computed at a value greater than 1 (30.3), indicating that the proposed system was energetically more advantageous than the single-phase oil system.

Coupled vibration of an annular plate-cylindrical drum structure with material-nonlinearity damping patches considering position-mistuned and stiffness-mistuned connections

Considering position-mistuned and stiffness-mistuned connections, the coupled vibration of an annular plate-cylindrical drum structure with material-nonlinearity damping patches is studied. These two mistuned connections are inevitable, but they are seldom concerned in published works. Moreover, the mistuned connections can cause local excessive vibrations, so vibration suppression is in demand. Spraying hard coatings with material nonlinearity is a good damping method. Their damping-related and stiffness-related parameters will change with strain, which will improve the vibration-reduction ability but bring obstacles to modelling. This paper focuses on the consideration of both mistuned connections and material-nonlinearity damping patches (MDP) and presents a general modeling method of connection-mistuned annular plate-cylindrical drum structures with MDP. Position-mistuned and stiffness-mistuned connections are emulated by developing the spring approach, and dynamic equations are created by combining Sanders’ shell theory, Kirchhoff’s plate theory, and Lagrange equation. Furthermore, the region decomposition approach is developed for considering the material nonlinearity, and an efficient solution is provided to solve the corresponding nonlinear complex equations. The study is adequately validated. Finally, numerical results indicate that mistuned connections cause the local-vibration behavior, frequency separation, and coupled vibration between substructures and modes. Moreover, mistuned connections also seriously affect the response curves and response cloud charts.

Annular self-organization of the two-dimensional vorticity condensate

Self-organization of the vorticity condensate of forced two-dimensional turbulence is examined in analogy with the mixing of a background planetary vorticity gradient in geophysical flows. Starting from the theoretical vorticity profile of the condensate, different scenarios are illustrated by the construction of idealized angular momentum conserving rearrangements of vorticity into a staircase profile similar to the potential vorticity staircase of $\beta$ -plane turbulence. Two sets of numerical experiments are then presented that illustrate a similar self-organization of the background vorticity gradient in fully turbulent flows. In the first set of experiments, the flow is initialized with a laminar vortex dipole corresponding to the theoretical condensate vorticity profile. A fluctuation vorticity field is then induced by a stochastic forcing at smaller scales, which induces an azimuthally symmetric self-organization of the laminar flow into distinct annular bands. In the second set of experiments, the flow is initialized from rest with stochastic forcing generating a turbulent inverse energy cascade, out of which emerges the condensate in a self-consistent evolution as the turbulent energy accumulates at the domain scale. A self-organization of the condensate is again observed, giving a distinct annular structure on top of the theoretically predicted condensate profile. A major difference from the potential vorticity staircase of geophysical flows is the emergence in many cases of significantly non-monotonic radial vorticity profiles.

Novel optimal structure design and testing of air-cooled open-cathode proton exchange membrane fuel cell

Air-cooled open-cathode proton exchange membrane fuel cells are miniature but effective energy conversion devices for both the mobile power station and unmanned equipment applications. However, the structure of the air-cooled open-cathode proton exchange membrane fuel cells still needs to be optimized to improve the system compactness and cell performance. In this study, an annular structure is designed, which offers a more uniform air velocity profile, higher air pressure difference, as well as more uniform temperature distribution with a minimum temperature gradient. Benefiting from the optimized annular structure, the assembly of the annular stack has an internal air duct, which could not only reduces the volume and weight of the stack, but also allocates the air more evenly. Results further indicate that the annular design increases the uniformity of velocity and temperature by around 3 times compared with traditional rectangular stack, it contributes significantly to the fuel cell performance by a 15% increase in power. This study provides an efficient strategy to improve the performance and extend the system reliability for future engineering application.

Optimization Study of Annular Wear-Resistant Layer Structure for Blast Furnace Tuyere

A new tuyere small sleeve coating structure that balances the high thermal conductivity of the copper substrate with the high wear resistance of the protective layer was developed in this paper. This structure can achieve a low-carbon blast furnace by reducing the heat loss from the tuyere. The 3D model was established via Solidworks for modeling and Ansys for numerical simulation, the temperature field of the annular wear-resistant layer structure tuyere small sleeve with different widths of the wear-resistant layer was analyzed and compared with the temperature and stress field of traditional tuyere small sleeve. The results show that the design of the annular wear-resistant layer structure of the tuyere small sleeve is more effective. The new annular wear-resistant layer structure for the tuyere small sleeve results in a decrease of 24 K in the average temperature of the wear-resistant coating. The comparison of this structure with tuyere sleeves without wear-resistant coatings shows a 16.7% reduction in heat loss, improves the wear resistance of the tuyere, providing new technological ideas for low-carbon blast furnace production. Compared with the tuyere sleeve completely covered with a wear-resistant coating, the maximum thermal stress of this structure decreased from 624.98 Mpa to 427.99 Mpa, resulting in a reduction of 31.5%, which is beneficial for the service life of the tuyere sleeve. The copper surface temperature of the new tuyere small sleeve is in a safe range when the temperature is below 2273 K.

A Two-Way Coupled Model of Visco-Thermo-Acoustic Effects in Photoacoustic Trace Gas Sensors

We introduce the first two-way coupled model for the thermo-viscous damping of a mechanical structure (such as quartz tuning fork) that is forced by the weak acoustic and thermal waves generated when a laser source periodically interacts with a trace gas. The model is based on a Helmholtz system of thermo-visco-acoustic equations in the fluid, together with a system of equations for the temperature and the displacement of the structure. These two subsystems are coupled across the fluid-structure interface via several conditions. With this model, the user specifies the geometry of the structure and the viscous and thermal parameters of the fluid, and the model outputs an effective damping parameter and a signal strength that is proportional to the concentration of the trace gas. This new model is a significant improvement over existing one-way coupled models in which damping effects are incorporated via a priori laboratory measurements. Analytical solutions derived for an annular structure show reasonable agreement between the one-way and two-way coupled models at higher ambient pressures. However, at low ambient pressure the one-way coupled model does not adequately capture thermo-viscous effects.

Coffee-ring deposits of polydisperse particles

The coffee-ring phenomenon has attracted attention for spontaneously concentrating suspended inclusions at the tri-phase contact line. Yet, little is known about how the size distribution of particle mixtures affects the annular structure. Here, instead of the classic power-law relation between the ring width and the initial volume fraction for monodisperse spherical particles in evaporative droplets, a logarithmic function is observed for polydisperse particle mixtures mimicking the size distribution of matters in material and biological research (e.g., Gamma distribution). The effect of particle size distribution on the evolution of ring deposits would inspire strategies for diagnostics, assembly, and manufacturing processes.

Simulation of gas-solid combustion characteristics in a 1000 MW CFB boiler for supercritical CO2 cycle

Supercritical CO2 (S-CO2) power cycle has become one of the most efficient and low-pollution cycle schemes to improve thermal power generation efficiency and reduce energy consumption around the world. In this study, the 3D physical model of a 1000 MW S-CO2 circulating fluidized bed (CFB) boiler with annular furnace is established to simulate the gas-solid combustion process based on the MP-PIC method under the Eulerian-Lagrangian framework. By comparing with the conventional water steam CFB boiler, the S-CO2 CFB boiler has a smooth and stable gas-solid flow pattern with good uniformity of the particle concentration and velocity distribution, indicating that the annular structure and the layout of the heating surfaces is conducive to the gas-solid flow uniformity. The gas-solid phase temperature distributes uniformly basically without sudden rise or sudden drop, and the temperature difference between the solid phase and the gas phase is not large, which reflects the good combustion uniformity of the S-CO2 CFB boiler. Compared with 300 MW and 600 MW S-CO2 CFB boilers, the 1000 MW one shows a higher carbon conversion rate, lower desulphurization effect, and lower nitrogen removal performance with the CO, NO, and SO2 outlet concentration of 0.002%, 5.8 mg/m3, and 125 mg/m3, respectively.

A triboelectric vibration sensor for detecting loose bolts in automobile

ABSTRACT Recently, the application of flexible sensors in mechanical equipment has attracted widespread attention. However, the design of vibration sensor materials and structures for complex mechanical environments still faces challenges. Hence, we proposed an annular structure CCTO/PDMS-based triboelectric nanogenerator (CP-TENG) as self-powered triboelectric automotive bolt tightness sensor. Due to the high dielectric properties of CCTO/PDMS film, the CP-TENG device can obtain high electrical output performance to achieve high sensitivity sensing. Through the annular structure design, CP-TENG devices can be integrated into bolt fittings with good structural compatibility. The output voltage and current of CP-TENG can monitor the different accelerations borne by the bolts from 9 to 60 m/s2. Moreover, by installing on the gasket, the CP-TENG device can also monitor bolt looseness to achieve early warning of the safety status of automotive components. This research can promote the development of self-powered sensor in the field of automotive bolt vibration monitoring.

Equivalent mechanical modeling and dynamic analysis of a large annular tensegrity structure

Equivalent mechanical modeling and dynamic analysis of a large annular tensegrity structure

Dynamic performance prediction of an annular tensegrity structure based on similitude method

Recently, the deployable antenna structure is designed and built extra larger to address the lack of observation accuracy and high resolution. However, this will bring new challenges for the performance testing of the prototype in a terrestrial environment. Similitude theory is a branch of methodology method that can reflect the basic configuration and characteristic of a reduced scale model. Therefore, this paper briefly introduces a conventional annular tensegrity that can be used by space deployable antennas. The Discrete Similitude Method is proposed to decompose a complex structure into equivalent beam or cable members. The similitude compatibility criteria of members is derived using the Discrete Similitude Method, along with the criteria of consistency of similitude scale factor and conservation of dimension. The criteria of consistency of similitude scale factor and conservation of dimension of the whole structure are also deduced to obtain the scale relationship of dynamic characteristics when the geometrical nonlinearity of beam and cable members are considered. Then, a similitude correction method to address the problem of the distortion in the size, load, and material properties of beam and cable member is proposed to study the dynamic similitude of annular tensegrity structures. The criteria of consistency of distorted coefficients of different beam and cable members are derived. Finally, the comparison of numerical and FEM results is presented to show that the dynamic performance prediction method has a high precision and can guide the design of reduced scale prototype. A 4 m prototype is fabricated and a modal experiment is tested. It is demonstrated that the 1st order natural frequency of the prototype can accurately predict for that of a 100 m oversized prototype.

Particle Trapping Properties of Metal Annular Slits under Vector Field Excitation

This article presents the particle capture performance of annular slits, which offer a simple alternative to complex micro/nano structures used to excite and focus surface plasmon polaritons (SPPs). Additionally, the annular slits are compatible with a variety of vector light fields, generating diverse SPP field distributions under their excitation. These SPP fields can be regulated by varying the vector light field parameters, thereby offering the annular slit structure the ability to flexibly capture and manipulate particles. The rotation and movement of captured objects can be achieved by changing the position and phase difference of the incident beams with linear polarization. Different material and sized metallic particles can be stably captured with a radially polarized beam excitation due to the strong convergence. These capabilities are demonstrated by evaluating the optical force and trapping potential based on the finite difference time domain (FDTD) simulation. This study provides valuable insights into the practical application of annular slits for particle capture and manipulation.

Study on heat transfer characteristics of annular pulsating heat pipe with temperature oscillation characteristic

A new annular structure of pulsating heat pipe (APHP) was designed for evacuated solar collector. To reduce the contact thermal resistance and alleviate the overheating problem, each tube of the pulsating heat pipe can be installed to fit snugly against the inner wall of evacuated tube. Experiments on filling ratio, heat transfer distance, inclination angle, and working fluid were carried out. The flow circumstances and heat transfer performance were analyzed based on the difference in frequency and amplitude of temperature oscillation curve and thermal resistance data. The results showed that high-frequency and low-amplitude temperature curve appeared when the APHPs were in the situation of low flow resistance, normally accompanied with better heat transfer effect. The optimum filling ratio and inclination angle are 60% and 60 °, respectively. The heat transfer performance of APHP decreased with the increase of heat transfer distance. The APHPs charged with self-rewetting fluid demonstrated a significant effect on heat transfer enhancement. Over different heat transfer distance, the application of self-rewetting fluid reduced the thermal resistance on average by 32.46%, 34.15% and 37.40%, respectively.