Ring Design Research Articles

Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

The implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value (text {K}_{text{mean}}) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower text {K}_{text{mean}} value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

A ring vibration isolator enhanced by shape memory pseudoelasticity

Performance enhancement of vibration isolation of a circular ring by means of a shape memory alloy (SMA) wire rope is investigated. The restoring and the damping force of the SMA are approximated by two cubic polynomials. The ring with the SMA wire along the horizontal diametral line is mathematically modeled by two coupled nonlinear partial differential equations with the boundary conditions. The nonlinear partial differential equations are discretized via the Galerkin method. The method of harmonic balance is applied to derive the expressions for frequency response and the force transmissibility of the circular ring design. The developed vibration isolation approach is successfully implemented to change the path of vibration transmission to attenuate the transmitted motion. The effects of the introduced horizontal SMA stiffness and damping on vibration isolation are examined. The resultant SMA stiffness is shown to extend the isolation range to lower frequencies, while the horizontal SMA damping has the ability to reduce the resonance response. The numerical simulations support the analytical results. Then, the isolation performances obtained employing different types of NiTiNOL (i.e., NiTi7, NiTi19/NiTi1, ST49/NiTi7, ST49/NiTi1) are compared. The results demonstrate that the SMA composed of NiTi19/NiTi1 is optimum for the ring isolation design. The developed ring beam vibration isolator reduces the transmissibility around the resonance frequency and performs better at high frequencies for appropriate types of SMA.

Ring Design with Rotating Movable Structure by Selective Laser Melting

Jewelry with movable structure is time-consuming and difficult to make by traditional jewelry manufacturing process. By 3D printing active structure, jewelry design works can be rapidly integrated by printing equipment, which overcomes the limitations of traditional jewelry manufacture. The authors compared and analyzed three kinds of 3D printing technology applied in jewelry design. Finally the selective laser melting was chosen to study the suitable movable structure for jewelry 3D printing, and a ring with rotating movable structure that is difficult to realize in traditional jewelry manufacturing process was designed and printed. The combination of advanced jewelry manufacture technology and contemporary jewelry art were tried to broaden. By optimizing the internal structure of the model, the problems of support interference and uneven gaps between parts in printing active structure were overcome. Meanwhile, the interaction between people and jewelry is enhanced with the rotating movable structure.

Design of shock-resistant miniaturized shipborne radar confluence ring

In order to reduce the overall size of the shipborne radar and improve the reliability of signal transmission, a miniaturized design has been carried out on the shipboard radar confluence ring. The miniaturized confluence ring adopted the electric contact form that the brush wires and the conductive ring are matched. The brush wires and the conductive ring coating used high-performance noble metal electrical contact materials, and the contact force was designed to be 0.1N to ensure the reliable and effective electrical contact. In addition, the dynamic design analysis method (DDAM) was used to analyze the shock resistance of the confluence ring. The test results showed that the size of the confluence ring had been reduced, all performance indicators met the requirements, and reliable transmission of various signals could be realized; the calculation results showed that the maximum impact stress of the confluence ring was less than the yield strength of the shell material, which met the requirements of the ship equipment shock resistance design requirements. The design method and analysis results have reference value and guiding significance for the miniaturization design and shock assessment of shipborne radar confluence ring.

The Three Dipole Kicker Injection Scheme for the ALS-U Accumulator Ring

Author(s): Ehrlichman, M; Hellert, T; Leemann, SC; Penn, G; Steier, C; Sun, C; Venturini, M; Wang, D | Abstract: The ALS-U light source will implement on-axis single-train swap-out injection employing an accumulator between the booster and storage rings. The accumulator ring design is a twelve period triple-bend achromat that will be installed along the inner circumference of the storage-ring tunnel. A non-conventional injection scheme will be utilized for top-off off-axis injection from the booster into the accumulator ring meant to accommodate a large $\sim 300$~nm emittance beam into a vacuum-chamber with a limiting horizontal aperture radius as small as $8$ mm. The scheme incorporates three dipole kickers distributed over three sectors, with two kickers perturbing the stored beam and the third affecting both the stored and the injected beam trajectories. This paper describes this ``3DK'' injection scheme and how it fits the accumulator ring's particular requirements. We describe the design and optimization process, and how we evaluated its fitness as a solution for booster-to-accumulator ring injection.

Intensification of the wastewater treatment process with electrolytic gases

High regulatory requirements for the quality of treated water discharged into watercourses and wear and tear of local treatment facilities dictate the need to develop new technological solutions in the field of water treatment systems. In this regard, technologies that implement methods of electrophysical or electrochemical impact on polluting components in the processed liquid have found wide application in the treatment of waste and substandard waters. In this case, on the one hand, in order to increase the efficiency of collecting pollutants, it is necessary to strive to increase the number and decrease the size of electrolytic gas bubbles providing this collection, and on the other hand, it is necessary to optimize the operating modes of the electrode system and the material execution of the electrodes themselves, since the time of their operation depends on this. To solve this compromise problem, the design of an electroflotator has been developed, in which an electrode system is installed in the lower part of the tank, consisting of vertical anodes and cathodes. Each pair of them has the shape of cylinders and is fixed on the side surfaces of the dielectric ring separating them. The height of the ring from above and from below is made greater than the height of the anode and cathode by an amount equal to the annular gap between the adjacent anode and cathode. This design of the spacer ring prevents current leakage from the cathode to the anode and, accordingly, the dissolution of the anode ends. If the height of the ring above and below is executed by an amount less than the annular gap, there is a twofold increase in the density of the anode current at the ends of the anode and cathode, intensifying the dissolution of the anodes and the ingress of dissolution products into the solution and onto the walls of the electrodes, increasing their electrical resistance and reducing the performance of treatment facilities by liquid to be cleaned.

Novel J-shaped impeller sealing ring for use in pumps: design and validation using simulation – Part 2

The impeller sealing ring in a pump is a critical component that plays an important role in reducing inner flow leakage. The nature of its design is closely related to the volumetric efficiency of the pump. This article provides details of a novel “J-shaped” impeller sealing ring design – in which the clearance length is extended through the use of a special bended structure – and explains its operating principles using fluid mechanics. In addition, a commercial double-suction split-case centrifugal pump is used to validate the new design scheme, and contractive computation results show that it offers a significant advantage in terms of volumetric efficiency, compared with conventional “L-shaped” structures. This work may provide a new, promising impeller sealing ring structure that has broad application in pumps.

Enhancement of Heterogeneous Microfluidic Immunosensors Using New Sensing Area Shape with Electrothermal Effect

In heterogeneous microfluidic immunosensors, the diffusion boundary layer produced on the sensing area represents a critical factor that limits the biosensor performance. A three-dimensional simulation using the finite element method on the binding reaction kinetics of C-reactive protein (CRP) has been performed. We present a new microfluidic biosensor based on a novel reaction-surface design without and with electrothermal force. Two reaction surface configurations were studied. The kinetic reaction rate was calculated with coupled Navier−Stokes, mass diffusion, energy, and Laplace equations. The numerical results reveal that the characteristics of a microfluidic biosensor are more enhanced by using the circular ring design of the sensing area coupled with the electrothermal force. The rate of initial slope related to the association phase is multiplied by a factor 2 when the voltage is increased from 10 to 15 V. The results prove to be valuable in designing new microfluidic biosensors.

Novel J-shaped impeller sealing ring for use in pumps: design and validation using simulation – Part 1

The impeller sealing ring in a pump is a critical component that plays an important role in reducing inner flow leakage. The nature of its design is closely related to the volumetric efficiency of the pump. This article provides details of a novel “J-shaped” impeller sealing ring design – in which the clearance length is extended through the use of a special bended structure – and explains its operating principles using fluid mechanics. In addition, a commercial double-suction split-case centrifugal pump is used to validate the new design scheme, and contractive computation results show that it offers a significant advantage in terms of volumetric efficiency, compared with conventional “L-shaped” structures. This work may provide a new, promising impeller sealing ring structure that has broad application in pumps. The first part of this article, which appears here, mainly describes background to the work, and the scheme and principles of the design. The second instalment will be published in the June 2021 issue of Sealing Technology.

Metal‐Free Synthesis of 2‐Aryl Quinazolines via Tandem C−H/N−H Bond Functionalization

AbstractC−N bond formation is crucial for the preparation of synthetic organic nitrogen‐containing heterocyclic compounds. This work provides a facile and highly efficient strategy (ca. ∼92 %) for the synthesis of quinazoline compounds, which involves tandem C−H/N−H bond functionalization using metal‐free conditions without the need for an external oxidant. Meanwhile, the reaction system exhibits good functional group tolerance and a wide substrate scope. Furthermore, our corresponding isotope tracking experiments have shown that dimethyl sulfoxide acts as a carbon source. Finally, this work affords a new strategy toward the further design and synthesis of heteroaromatic rings.

Identification of In-Cylinder Aerosol Flow Induced Emissions due to Piston Ring Design in a DISI Single Cylinder LV Engine Using Oxygenated Synthetic Fuels

<div class="section abstract"><div class="htmlview paragraph">In the near future, pollutant and GHG emission regulations in the transport sector will become increasingly stringent. For this reason, there are many studies in the field of internal combustion research that investigate alternative fuels, one example being oxygenated fuels. Additionally, the design of engine components needs to be optimized to improve the thresholds of clean combustion and thus reduce particulates. Simulations based on PRiME 3D® for dynamic behaviors inside the piston ring group provide a guideline for experimental investigation. Gas flows into the combustion chamber are controlled by adjusting the piston ring design. A direct comparison of regular and synthetic fuels enables to separate the emissions caused by oil and fuel. This study employed a mixture of dimethyl carbonate (DMC) and methyl formate (MeFo). These two components have no C-C bonds, and the mixture displayed extremely good performance in terms of the particle number (PN) emissions on an ambient level published in previous studies. This fuel property is employed in this study to identify oil induced, engine-out PN-emissions, while the combustion process remains almost identical to that of conventional gasoline. The PN-emissions are measured and subdivided into two ranges: larger than 10 nm and larger than 23 nm.</div><div class="htmlview paragraph">It was demonstrated that merely changing the piston ring design has an impact on raw PN engine emissions and gas flow behavior in the piston assembly. An increase in PN-emissions and lower blow-by level could only be detected by changing the piston ring design. With reduced, predicted fluid flows into the combustion chamber, lower VOC emissions could be observed during motored runs. The adaptations in the tested piston ring design demonstrate that it is possible to improve particulate emissions by modifying the piston ring group.</div></div>

Numerical analyses of liquid slosh by Finite volume and Lattice Boltzmann methods

Liquid slosh phenomenon has been widely observed in aerospace and aeronautic engineering. In this paper, Finite volume method (FVM) and Lattice Boltzmann method (LBM) are proposed to perform the quick evaluation of liquid slosh behaviour under different container designs. The effectiveness of the numerical models is validated by the existing experimental data. The validated models are then used to study the fuel slosh behaviour with different baffle ring designs. By inserting the baffle to divide the liquid region into multiple sections, the slosh motion of the liquid is suppressed. At the same time, the effectiveness and time efficiency of LBM model have been demonstrated by a parallel comparison with the results from the FVM model. It is found that the computational time cost of LBM model is only around 7.0% of the time cost for FVM model without compromise of the numerical accuracy. This supports the future utilisation of LBM model in quick design evaluation of slosh-like problem.

Containment and Arrest of Blade Shedding in Gas Turbine Engines Using Novel Dual-Ring Design

Abstract In this paper, we examine the energy absorption and containment capabilities of a newly proposed dual-ring design accounting for interactions between a released blade and fully bladed fan disk using three-dimensional finite element analysis. The components of this dual-ring design are strategically selected to ensure high energy absorption and high impact resistance, thus leading to reduced damage of the disk and increased safety. Three containment ring designs are examined: (i) conventional single-ring design composed of one of titanium, aluminum, or Kevlar; (ii) a newly proposed aluminum-Kevlar dual-ring arrangement; and (iii) dual-ring arrangement with an interfacial gap between them to arrest and contain the released blade and ensure free passage of the trailing blades. The results of our numerical simulations indicate that although the single-ring design resists penetration and contains the released blade within the confines of the disk, it does not remove the released blade from the path of the trailing blades leading to severe damage to the fan disk. On the contrary, our new dual-ring design, which contains an interfacial gap, has potential to successfully arrest the released blade within the confines of the ring and out of the path of the trailing blades. This design can significantly reduce the impact damage to the fan disk and reduce kinetic energy of the released blade to near zero in less than half a rotation of the fan disk.

3D-gedrucktes Siliciumcarbid als Gleitringwerkstoff

Reaction bonded silicon carbide is well known for use as axial seal faces. The properties have been optimized in order to improve the performance of dynamic seals. 3D-printed silicon carbide will be introduced. The new material allows forming much more complicated shapes and seal ring designs. The new material shows a different structure compared to compression molded reaction bonded silicon carbide due to the special manufacturing process. Therefore, first comparative tests of seal-rings under marginal lubricated conditions have been performed. The results are presented and the possible use of 3D-printed silicon carbide in the sealing technology is discussed. A first fundamental design study implies the potential of producing seal rings with an additional functionality. A simplified model of a seal ring with internal structures is shown and some ideas will be shared whether additional benefit could be achieved.

Lubrication and Fluid Film Study on the Vane Tip in a Vane Pump Hydraulic Transmission Considering a Fluid and Structure Interaction

Abstract A mathematical modeling approach to determine fluid film thickness on the vane tip in a vane pump transmission is developed. The transmission is based on a double-acting vane pump with an additional output shaft coupled to a floating ring. Owing to the floating ring design, the internal viscous friction helps to drive the output shaft, whereas the friction is turned into heat in a conventional vane pump. To study the mechanical efficiency, it is crucial to investigate the fluid film thickness between the vane tip and the ring inner surface. The modeling approach in this study takes the interactions between vane radial motion and chamber pressure dynamics into consideration, without using a computational fluid dynamics approach. The lubrication on the vane tip is considered as elasto-hydrodynamic lubrication and the fluid film thickness calculation is based on the Hooke lubrication diagram. Results show that the developed simulation model is capable of revealing the fluid film thickness change and vane radial motion in different operation regions. Sensitivity studies of several parameters on the minimum fluid film thickness are also presented.

Superhydrophobic and superoleophobic property enhancement on guard ring micro-patterned PDMS with simple flame treatment

Effects of new micro-structure design, a flame treatment process, and the addition of semifluorinated silane (SFS) on an improvement of superhydrophobicity and superoleophobicity of PDMS surfaces were investigated in this study. PDMS and PDMS-SFS surfaces with the special design of circular rings and eight stripe supporters (C-RESS) with a hexagonal guard ring (HGR) structure were found to be the most durable which maintained their superhydrophobicity after scratch tests. The flame treatment at 700 °C/15 s formed a unique nanoscale flower-like on the PDMS-SFS surface. A formation of re-entrant micro-structure on the C-RESS with the HGR structure exhibited superhydrophobicity and superoleophobicity with water and ethylene glycol contact angles of 160.5° ± 2.0° and 160.2° ± 6.6°, respectively. The addition of the SFS was found to increase surface roughness and decrease surface energy. In conclusion, the flame-treated C-RESS with the HGR structure on the PDMS-SFS surface is considered one of the promising antifouling approaches in several applications.

Beam-based alignment at the Cooler Synchrotron COSY as a prerequisite for an electric dipole moment measurement

The Jülich Electric Dipole moment Investigation (JEDI) collaboration aims at a direct measurement of the Electric Dipole Moment (EDM) of protons and deuterons using a storage ring. The measurement is based on a polarization measurement. In order to reach highest accuracy, one has to know the exact trajectory through the magnets, especially the quadrupoles, to avoid the influence of magnetic fields on the polarization vector. In this paper, the development of a beam-based alignment technique is described that was developed and implemented at the COoler SYnchrotron (COSY) at Forschungszentrum Jülich. Well aligned quadrupoles permit one to absolutely calibrate the Beam Position Monitors (BPMs). The method is based on the fact that a particle beam, which does not pass through the center of a quadrupole, experiences a deflection. The precision reached by the method is approximately 40μm. Some consequences for the design of a new high precision storage ring for EDM mesasurements are discussed.

Corona and Electric Field Distribution Analysis in 400 kV Line Insulators

The performance of insulator strings in transmission lines can be improved by corona rings owing to their electric field grading property. The insulation performance of the string depends on the corona ring parameter settings. In this study, the design of a corona ring for a 400 kV non-ceramic overhead line insulator is presented. Two parameters were altered during the investigation, ring measurement (R) and ring tube breadth (r) while maintaining a constant ring height (h). Based on electric field distribution, the proposed composite insulators were compared with glass insulators. Simulation studies were performed for the insulator strings, including corona rings with different design parameters. The corona discharge and optimal configuration results were analyzed, and it was found that the electric field was lower with composite insulators.

Analytical and Numerical Model of Aluminum Alloy Swaging Ring Design to Study the Effect on the Sealing for Piping Systems

In various fields of engineering, the assembly and repair of hydraulic installations are accomplished by joining the pipes. In such applications, the ring swaging method is used to connect the fittings to the pipes by means of a hydraulic hand tool. The basis to develop a swaging tool relies on the knowledge of the design parameter that influence plastic deformation of the swaging ring. In addition to build control over the design parameters, it is necessary to join pipes under severe conditions such as cryogenic vacuum and constrained space which require an intact sealing. In this study, the effect of swaging ring designs on sealing and strength has been examined and different swaging methods have been investigated by finite element modeling methods. Based on the obtained results, the analysis methodology of ring swaging and the characteristic impact of swaging ring design on the sealing of pipe connection are shown. The prime novelty of the study is to report the impact of swaging ring design and geometry on sealing efficiency of the pipe connection. The results of the study open new avenues for the development of efficient tools for designing swaging rings. Doi: 10.28991/cej-2021-03091641 Full Text: PDF

Design of Deterministic Sparse Fractal Array with Haferman Counter-Diagonal Fractal Tapering Technique for Modern Wireless Systems

Deterministic fractal structure is a repetitive geometry based structure having applications in various regions of science and engineering. Fractal antennas and array antennas are artistic structures and they are finding much attention in recent years owing to their feasible properties. A few deterministic fractal arrays owing to the fractal dimensional design methodology are thinned arrays, but the great concern for these types of array antennas is the great number of antennas present at higher level iteration and as well as expansion levels. The present research work discusses the feasibility of reducing antenna elements at higher expansion and iteration levels of fractal arrays with a new type of tapering technique named as Haferman counter-diagonal fractal tapering. Different types of fractal arrays created using a sub array of concentric elliptical ring design methodology have been considered for the application proposed tapering technique. Owing to the proposed technique, nearly 40% to 50% of the antenna elements thinned while maintaining fully populated array factor properties. The proposed technique can simplify the design complexity of fractal arrays and reduce the designing cost.