Annular Ring Research Articles

Screen‐printed dual‐band wearable textile antenna incorporated with EBG structure for WBAN communications

SummaryA dual‐band, wearable coplanar microstrip patch antenna (CPW) integrated with electromagnetic bandgap structure (EBG) to operate dual wireless bands at 2.48 GHz industrial, scientific, and medical band (ISM) and 5.2 GHz WLAN. The proposed textile wearable antenna and EBG structure are screen‐printed using silver conductive ink on the cotton polyester substrate (εr = 1.6) for flexible wearable applications. A 3 × 3 EBG array is realized by a concentric square patch surrounded by the annular square ring to reduce back radiation and increase the forward gain and front‐back ratio. The proposed EBG‐backed antenna, compared with the conventional CPW‐fed antenna, improves forward gain from 2.18 to 6.59 dB at 2.48 GHz and 3.5 to 7.03 dB at 5.2 GHz. Moreover, the EBG array is used to isolate the human body from the antenna and reduces the specific absorption rate (SAR). The antenna is performed with a human phantom tissue model, which exhibits a specific absorption rate of 0.12 W/kg, and 0.260 W/kg for 1 g tissue at 2.48 GHz and 5.2 GHz, respectively.

A novel broadband and high-gain compact annular ring microstrip antenna for satellite applications

Abstract This article presents a novel compact design of an annular ring microstrip antenna (ARMSA), which has two stacked annular rings and is fabricated on a FR4 substrate for radar and satellite applications. The presence of different kinds of slots made the design of the recommended antenna very unique for Ku band applications. This novel compact structure of the antenna provided enhanced bandwidth and high gain. The suggested antenna works in Ku band and has 2.70 GHz bandwidth and 8.42 dB gain, which makes it suitable for satellite applications. The quality parameters of the proposed annular ring microstrip antenna have been compared with other existing annular ring microstrip antennas, which shows its efficient performance.

Miniaturized Multi-band Millimeter-Wave Vivaldi Antenna with Performance Optimization at 28 GHz for 5G MIMO Applications

A novel design for Vivaldi antenna is introduced to operate in more than one frequency band in the millimeter-wave spectrum range with high gain. The proposed Vivaldi antenna is planar and printed on both sides of Rogers 3003C flexible substrate. A parasitic annular ring is added to each arm of the Vivaldi antenna to adjust the impedance matching and maximize the gain. The dimensions of the antenna are optimized using the CST microwave simulator to obtain the best impedance matching bandwidths and highest gain in a compact-size antenna. The 28-GHz band is then selected due to its importance to enhance the gain and improve the operating bandwidth for the 5G applications. A gain of 10 dBi and bandwidth of 6.1 GHz are obtained at 28 GHz. A multiple-input multiple-output (MIMO) antenna system is then designed for pattern diversity for the fifth-generation mobile applications. The performance of the MIMO system is evaluated regarding the envelope correlation coefficient and the diversity gain showing good results. The optimized antenna is fabricated and its return loss and radiation patterns are measured showing good consent between the simulations and the practical work. The MIMO antenna system is also fabricated, and its performance is measured regarding the reflection and coupling coefficients showing good agreement between the measurements and simulations.

Influence of Fixed Ring Gear Structural Compliance on the Quasi-Static and Dynamic Response of Epicyclic Gear Sets

Abstract The structural compliance of annular ring gear can significantly influence the quasi-static and dynamic performance of an epicyclic gear set. As powertrain components are continually being optimized to their design limits, this influence becomes prominent and can no longer be ignored. The current paper will study the impact of ring gear compliance on the dynamic response of epicyclic gear sets, in fixed ring kinematic configuration. To achieve this objective the current study will incorporate a finite element based ring gear formulation into the three-dimensional planetary load distribution model of Ryali and Talbot [1]. The proposed model employs a modified simplex algorithm to iteratively solve for the elastic gear mesh contacts in conjunction with a numerical integration scheme, which enables it to inherently capture the influence of several component and system level design variations. The developed formulation is used to conduct parametric studies involving different planetary gear designs, ring gear fixtures (bolted vs. splined), and operating conditions (quasi-static, dynamic). In the case of a splined ring gear fixture, an external splined tooth contact model is developed, which will be used to validate the model against the quasi-static experiments of Ligata et al. [2]. The discussed results demonstrate the fidelity of the developed model, thus making it an excellent tool for the design and analysis of planetary gears with thin annular ring gears.

Isolation and characterization of duck viral enteritis (Duck plague) virus from ducks in field outbreaks in Bangladesh

Duck viral enteritis (DVE) also known as duck plague (DP) is a fatal viral disease of ducks globally that causes huge economic losses in the duck industries. The main objectives of the current study were: the isolation of the circulating duck viral enteritis virus (DVEV) from clinical specimens of field outbreaks, molecular identification of the virus and genetic characterization of DVEVThe natural outbreaks of duck plague (DP) were reported between February and June 2018 on three commercial duck farms located at Netrokona, Mymensingh and Nilphamari districts of Bangladesh. A total of 42 dead ducks were collected from the three farms. Postmortem examination of dead ducks was carried out and gross lesions of the visceral organs were recorded.Liver and spleen samples were collected aseptically and 10% viral inoculum was prepared from liver and spleen. Isolation of DVEV was done by injecting viral inoculum into 9-13 days old embryonated duck eggs through the chorioallantoic membrane (CAM) route.Molecular detection of DVEV in liver, spleen and CAM homogenate was performed by PCR targeting 446 bp fragment of DNA polymerase gene of DVEV. Phylogenetic analysis was carried out by comparing the amino acid sequence of field isolatesof DVEV with the amino acid sequence of global isolates of DVEV deposited in the GenBank. Enlargement of the liver and spleen, abdominal haemorrhage, and annular rings of the trachea were seen in the affected ducks which were characteristics gross lesions in DVE.18of 42 samples (42.85%) were found positive for DVEV by PCR assays. Embryos of duck experimentally inoculated with DVEV were found dead at 3-5 days post infection.Degenerated blood vessels of the CAM, dwarfism of the embryos was observed. The phylogenetic study revealed that the DVEV isolates causing disease outbreak in ducks in the current study were 100% similar to the isolates of DVEV thatpreviously reported from Bangladesh, Vietnam and China.

Plasmonic metasurfaces of cellulose nanocrystal matrices with quadrants of aligned gold nanorods for photothermal anti-icing

Cellulose nanocrystals (CNCs) are intriguing as a matrix for plasmonic metasurfaces made of gold nanorods (GNRs) because of their distinctive properties, including renewability, biodegradability, non-toxicity, and low cost. Nevertheless, it is very difficult to precisely regulate the positioning and orientation of CNCs on the substrate in a consistent pattern. In this study, CNCs and GNRs, which exhibit tunable optical and anti-icing capabilities, are employed to manufacture a uniform plasmonic metasurface using a drop-casting technique. Two physical phenomena—(i) spontaneous and rapid self-dewetting and (ii) evaporation-induced self-assembly—are used to accomplish this. Additionally, we improve the CNC-GNR ink composition and determine the crucial coating parameters necessary to balance the two physical mechanisms in order to produce thin films without coffee rings. The final homogeneous CNC-GNR film has consistent annular ring patterns with plasmonic quadrant hues that are properly aligned, which enhances plasmonic photothermal effects. The CNC-GNR multi-array platform offers above-zero temperatures on a substrate that is subcooled below the freezing point. The current study presents a physicochemical approach for functional nanomaterial-based CNC control.

A Total Randomized SLP-Preserving Technique with Improved Privacy and Lifetime in WSNs for IoT and the Impact of Radio Range on SLP.

Enhanced source location privacy and prolonged network lifetime are imperative for WSNs-the skin of IoT. To address these issues, a novel technique named source location privacy with enhanced privacy and network lifetime (SLP-E) is proposed. It employs a reverse random walk followed by a walk on annular rings, to create divergent routing paths in the network, and finally, min-hop routing together with the walk on dynamic rings to send the packets to the base station (BS). The existing random walk-based SLP approaches have either focused on enhancing only privacy at the cost of network lifetime (NLT) or have aimed at improving the amount of privacy without degrading the network lifetime performance. Unlike these schemes, the objectives of the proposed work are to simultaneously improve the safety period and network lifetime along with achieving uniform privacy. This combination of improvements has not been considered so far in a single SLP random walk-based scheme. Additionally, this study investigates for the first time the impact of the sensors' radio range on both privacy strength and network lifetime metrics in the context of SLP within WSNs. The performance measurements conducted using the proposed analytical models and the simulation results indicate an improvement in the safety period and network lifespan. The safety period in SLP-E increased by 26.5%, 97%, 123%, and 15.7% when compared with SLP-R, SRR, PRLPRW, and PSSLP techniques, respectively. Similarly, the network lifetime of SLP-E increased by 17.36%, 0.2%, 83.41%, and 13.42% when compared with SLP-R, SRR, PRLPRW, and PSSLP techniques, respectively. No matter where a source node is located within a network, the SLP-E provides uniform and improved privacy and network lifetime. Further, the simulation results demonstrate that the sensors' radio range has an impact on the safety period, capture ratio, and the network lifetime.

Poster Session II: Understanding scattering in high-resolution retinal imaging.

In conventional fundus images the contrast relates to scattering and absorption of light. Here, we report on modeling of high-resolution retinal imaging to understand the role of mitochondria light scattering in the ellipsoid of photoreceptors. We evaluate the directionality appearance of the photoreceptors, and its relation to drusen appearance in age-related macular degeneration (AMD). The refractive index contrast of the mitochondria collectively resembles that of micron-sized reflectors. Obliqueness of the scattering results in vignetting by the pupil that impacts on the brightness of the photoreceptors. Our hypothesis is that in early-stage AMD, drusen will perturb the photoreceptor alignment and thus cause oblique scattering and reduced brightness on the slope of the drusen in high-resolution retinal images. We model how this affects the observable photoreceptor mosaic both in the healthy eye and in eyes with AMD. The results confirm that the annular dark ring around drusen is likely caused by oblique scattering. We use a model eye to test the hypothesis with a reflective mask emulating the photoreceptor mosaic An SLM is used for amplitude modulation in the pupil and differential imaging allows for capturing off-axis images with an appearance like that of phase contrast images. Further refinement of the model eye may be a valuable way to test new imaging modalities prior to their implementation in the real eye.

Rearrangement of the Conformations of Polyampholitic Macromolecules on the Surface of a Charged Spherical Metal Nanoparticle in an Alternating Electric Field: Molecular Dynamic Simulation

The rearrangement of the conformational structure of polyampholytic polypeptides on the surface of a charged spherical gold nanoparticle with its polarity intermittently changing over time was studied using molecular dynamics modeling. The angular distributions of the polypeptide atoms, as well as the radial distributions of the macrochain atomic density in the equatorial region of the nanoparticle with differentiation according to the types of links, were calculated. The polyampholyte shell acquired an annular shape, and the resulting macromolecular ring was located around the charged nanoparticle perpendicularly to the vector of the external electric field strength. With an increase in the charge of the nanoparticle, the ring belt was ordered according to the types of macrochain links, forming concentric annular layers. The diameter of the macromolecular ring depended on the law of distribution of charged units in the macrochain. At elevated temperatures the annular macromolecular ring was deformed at the moments of the highest polarization of the nanoparticle.

Design of high-performance miniaturised circular slotted microstrip power dividers

Creating annular slotted rings within the circular microstrip patch power divider facilitates the realization of a new power divider configuration, which provides multifaceted features like miniaturization, decreased insertion loss, increased isolation, and fractional bandwidth enhancement, which collectively imbue the device with heightened operational efficacy. The present manuscript delineates the configuration, evaluation, analysis and design of these centre-fed Circular Slotted Power Dividers (CSPDs) endowed with annular slotted rings that have been engineered to function with superior efficacy.An analytical framework has been proposed for prognosticating the operational characteristics and design details of the proposed microstrip power divider by combining the known behaviour of its two component structures, namely, the inner Circular Micro-Strip Structure (CMSS) and the outer Annular Micro-Strip Structure (AMSS). The validity and accuracy of this framework have been ascertained by means of numerical simulations as well as practical measurements of the fabricated CSPDs. In addition, a parametric analysis is conducted to scrutinize the effects of varying the permittivity of the substrate, the circular radius, the annular ring radii, and the annular ring width, on the power divider's operational parameters. The insights gleaned from this analysis are subsequently utilized to optimize the proposed mathematical design procedure of the CSPDs.Furthermore, the manuscript expounds upon the assessment of the influence of multiple annular rings incorporated within the CPDs on further miniaturization and enhancement of the bandwidth. These enhanced structures are named as CSPD with Dual Slotted Rings (CDSR).

Mitral annular disjunction; how accurate are we? A cardiovascular MRI study defining risk

AimsMitral Annular Disjunction (MAD) refers to embryologic fibrous separation between mitral annular ring and basal left ventricular myocardium. Since its original description, the role of MAD in arrhythmic mitral valve prolapse (MVP) has been the subject of active research. In this study we sought to assess prognostic and imaging characteristics of MVP patients with and without underlying MAD. Methods and resultsPatients with posterior or bi-leaflet MVP were retrospectively identified via a review of all patients referred to our cardiac magnetic resonance (CMR) imaging laboratory from January 2015 to May 2022. MVP patients were further stratified by underlying MAD status. A total of 100 MVP patients undergoing CMR imaging (52 MVP patients with posterior MAD) were retrospectively identified with female comprising 55 % of the cohort. MVP patients with MAD were more likely to have an abnormal basal inferolateral/ papillary muscles LGE (51 % vs 21 %, p < 0.01). Posterior MAD longitudinal disjunction gap in ‘mm’ was a predictor of ventricular tachycardia (VT) [1.29, p = 0.01)]. Using ROC curve analysis, a disjunction gap of ≥ 4 mm was predictive of VT (AUC-0.71, p < 0.01), and incorporation of LGE in ROC model further improved AUC to 0.78 confirmed via Akaike information criterion (p < 0.01). ConclusionAbnormal LGE involving basal inferolateral myocardium and papillary muscles may provide etiologic substrate for arrythmia in MVP patients.

Implementation of a Reduced Order Model for rotating seal annular leakage flow inside a centrifugal pump

Sustainability and net zero emissions targets drive the importance of turbomachinery design, optimisation, and efficient operation in modern geoenergy systems. To further enable integration of advanced large-scale technologies, accurate and resource-efficient simulations of complex equipment and systems need to be completed readily. An approach to simulate internal leakage flows of centrifugal pumps is presented, an important factor that influences equipment operation efficiency.One significant challenge when internal leakage flow is investigated is achieving sufficient simulation detail in the flow regions separating rotating and stationary components where close-running clearances are present. Computational fluid dynamics (CFD) meshes typically require excessively fine resolutions of node points in these situations for accuracy. For example, the typical annular suction wear ring clearance ranges between 0.1–0.5 mm, whilst impeller diameters and other geometric properties have length scales from 600–1200 mm or even larger.A reduced order model (ROM) of an annular seal configuration was developed that allows for analytical calculation of the leakage flow by implementing user scripting in the CFD solver setup. The ROM implementation has a low symbol count and does not require any type of logic and/or recursive and iterative functionality. Thus, fine and resource-intensive meshing can be robustly eliminated and replaced by a sufficiently detailed ROM that contributes leakage flow effects to the overall simulation.Leakage flow through the suction wear ring of a high differential head (ΔH), high flow rate, double suction centrifugal pump with water as working fluid was used as a case study for ROM development. The calibrated model was verified against a commercial fluid dynamics software package and achieved a level of precision of 2.4% with σ=0.0118 in a wide operating range of 10m⩽ΔH⩽350m and fluid temperature (T) of 283.15K⩽T⩽353.15K.The leakage flow calculated by the ROM was proven to be accurate and therefore capable of accounting for a range of pressure heads, incorporating surface roughness effects and temperature variations, and adaptable for various fluids. Guidance for the implementation of the ROM in the Ansys CFX solver environment is also provided to aid future work.

Bellactis lux n. sp. (Cnidaria: Anthozoa: Actiniaria: Aiptasiidae), a new sea anemone from the Gulf of Mexico.

Here we describe a new species of sea anemone from the family Aiptasiidae based on specimens collected from the Gulf of Mexico (USA: Florida & Alabama). Accounts of this species have been known since the early 1990s, primarily from an underwater field guide and hobbyist aquarium literature under the name Lightbulb Anemone. We describe it as a new species from the genus Bellactis based on anatomy, histology, and cnidom. Members of this species are small in size, with a smooth, typically contracted column divided into regions based on color and bearing rows of two or three elevated cinclides in the mid column. Their tentacles are distinctive, translucent, distally inflated and can be bulbous in shape, with sub annular rings. This description synthesizes information about Bellactis and contextualizes what is known about its diversity in light of other members of the Aiptasiidae.

A Laser Triangulation Displacement Sensor Based on a Cylindrical Annular Reflector

The ellipticity of the spot caused by laser jitter has a significant effect on the measurement accuracy of the traditional laser triangulation method. In order to overcome the influence of laser characteristics on measurement and improve the accuracy of displacement measurement, this paper proposes a measurement model for a laser displacement sensor based on a cylindrical annular reflector. A physical prototype is designed through parameter optimization using NSGA-II, and a two-step detection algorithm is proposed for the imaging ring of the prototype. The algorithm performs contour thinning after rough positioning of the imaging annular ring, and then performs precise detection. Through physical experiments, it is verified that the repeatability error of this method can reach below 0.02%, and the accuracy is significantly improved compared to traditional laser triangulation displacement sensors. Meanwhile, the measurement results of displacement show linearity. The optical path design of this sensor is simpler than the previously proposed rotational symmetrical laser triangulation displacement sensor, which has good application prospects.

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.

Direct printable X-band low profile broadband reflectarray antenna using copper foils

This work reports on a compact and broadband reflectarray antenna that can be directly applied to the exterior surface of a nanosatellite. The design is composed of an annular ring with a wheel-shaped concentric structure loaded with two circular stubs acting as delay lines for maximum phase angle coverage. The design offers a phase variation of 576° in the X-band along with a peak measured gain of 26.6 dBi and an aperture efficiency of 49.24%. The design also offers low side lobe levels of −13 dB and −18 dB in both E- and H-planes at 11 GHz, respectively. Cross-polarization discrimination is also sufficiently large and is better than −32 dB and −36 dB for E- and H-planes, respectively. Moreover, the proposed printable reflectarray exhibited a 1-dB gain Bandwidth (BW) of 31.5 %. The design is produced by applying copper foils on float glass with a thickness of 2 mm as a proof of concept.

An optically transparent dual-band frequency selective surface for polarization independent RF shielding

This article reports on a compact dual band, Frequency Selective Surface (FSS) based spatial filter for Wi-Fi and WLAN shielding applications on a transparent glass surface with optical transparency of 70%. The unit cell comprises an outer square loop resonator with a disconnected and concentric annular ring resonator. To introduce frequency tuning and compactness T shape stubs are strategically loaded on these resonators and it is ensured that the mutual coupling remains minimal. The outer square resonator suppresses the 2.4 GHz band, and the inner circular ring resonator stops the 5.4 GHz band. The unit element is four-fold symmetric thus it offers complete polarization independence. A detailed parametric and electromagnetic field analysis has been conducted to elucidate the significance of different sections of the unit element. An equivalent lumped circuit model is also derived for the proposed unit element to better explain the underlying working mechanism. A finite prototype of 15 × 11 elements is fabricated on a soda lime float glass by using ordinary adhesive copper foils with a standard chemical etching process. Polarization independence and angular stability up to 45° are measured and compared with the simulated responses. The FSS shield offers frequency suppression up to 45 dB and 43 dB for 2.4 GHz and 5.4 GHz bands respectively. With high optical transparency, the design allows maximum light through it and causes no extra burden on energy consumption for indoor applications. The compact dual band design and the possibility of direct application on host surfaces like glass windows and doors make this design an excellent candidate for data security and privacy applications in secure installations with an esthetically pleasing outlook.

A novel mechanical joining method for sheet-tube structures by annular ring compression

Joining by forming has lately received great attention for connection between sheets and tubes due to its high joining efficiency, simple operation, and excellent joining strength. However, protrusion or indentation often occurs adjacent to the joints and, in some cases, the sheet warps, seriously affecting the performance of the connector. To overcome this problem, we propose a novel joining by forming process by compressing an accessory ring to produce the annular squeezing of the sheet, thus forming high-quality joints with smooth surfaces. A numerical-experimental analysis was adopted to identify the influence of the ring width and height on the joint cross-section, effective strain, tube thickness, and flow velocity. To assess the performance of the enhanced joint, its mechanical properties, microstructure, and failure modes were also analyzed. The results showed that the ring width and height have a significant effect on joint strength. Compared with the original joining process without the ring, the joint utilizing a wider ring can obtain higher pull-out loads (58.9% higher) to detach the sheet from the tube, while no sheet warpage happens for excessive local deformation. The utilization of larger and higher rings also motivates the increase of the pull-out strength. In some cases, tube plastic instability can be triggered during the pull-out tests, thus avoiding the full detachment of the components and contributing to the safety of the mechanical joint. Compared with the non-deformation zone, the grains in the deformation zone of the sheet are compressed and become elongated, and there are inclined separation bands between the two regions. This paper provides a new and efficient method for manufacturing sheet-tube structures with high joining strength.

Design and Manufacturing of a Hexapattern Frequency Selective Surface Absorber for Aerospace Stealth Application.

Integrated frequency selective surface (IFSS) absorbers with larger bandwidth, effective reflection loss, polarization-insensitive characteristics, angular stability with compact/thin design, and ease of fabrication have captivated significant importance in stealth technology. Herein, we report on an IFSS absorber that has been designed, simulated, and implemented for manufacturing to achieve effective stealth properties. Initially, frequency selective surface (FSS) layers have been designed that comprise a closed centroid honeycomb structure surrounded with four annular hexagonal rings, splitted, alternatively, and enveloped with four L-shaped elements. The simulated pattern has been optimized on glass fabric for reflection loss (RC, dB) at a thickness of ∼0.1 mm by choosing sheet resistance of pattern 110 Ω/□. A FSS layer combined with interlayer lossy dielectric laminates (1.8 mm) and a carbon-fabric-reinforced-plastic ground has been simulated as an IFSS absorber. The performance of RC, in normal and angular configuration (0-60°), under transvers an electric/magnetic mode of polarization, including analysis of the displacement current, volume power loss distribution, and complex admittance has been carried on IFSS. Subsequently, the proposed absorber has been fabricated using customized carbon-based resistive ink imprinted on glass fabric by mask lithography compounded with laminates (a carbon black powder/epoxy composite) and ground. Their manufacturing details, including free space and anechoic chamber RC measurements, have been presented. The simulated and experimental RC performances of the absorber are found to be in good agreement, possessing minimal 10 dB reflection loss (90% absorption) with a sample thickness of 1.9 mm (0.05λL, where λL corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms.

High performance of photonics crystals Demux with an integrated channel drop filter based on annular periodic ring cavity

Abstract In this work, we are interested in the design of a basic filter structure based on an annular ring cavity where we study its characteristics and its performance in terms of transmission and selectivity of the signal. The basic structure is a 2D photonic crystal (PC) with holes in the substrate which are more suitable for different PC manufacturing processes. Based on the optimization of the filter structure results, we created a high performance structure and improved a 4 channels demultiplexer (DEMUX) with an optical parameters which are the transmission efficiency, the quality factor and the crosstalk with average values of 97.25, 3171 and −26.58 dB, respectively, it had a significant role in optical communication networks. The compact size of the proposed DEMUX is 211.7 μm2 which is suitable for the integrated optics. To determine the photonic band gap (PBG) of our proposed structure, we used the plane wave expansion (PWE) method and the finite difference time domain (FDTD) method used to study normalized transmission.