Ring Design Research Articles

Static Stiffness Parametric Studies of Newly Conceptualized Inter Shaft Squeeze Film Damper (ISSFD) Rings

Most of the modern gas turbine engine designs requiring super critical operations will often have squeeze film dampers (SFDs) on the high pressure spool bearing as an inevitable feature. However, Squeeze Film Dampers are not very common for inter-shaft bearing applications and are still in the research and development stage. The current effort concentrates on static stiffness parametric studies based on newly conceptualized intershaft squeeze film damper (ISSFD) ring design suitable for space constrained intershaft bearing application of a typical two spool configured system. The work involves static stiffness evaluation of three and four grooves ISSFD rings by varying the groove angle/groove length/subtended angle of groove & hence the overlapping angle of grooves by conducting static tests on a dedicated static stiffness evaluation test rig designed and fabricated for the purpose. The pattern of circumferential variation of stiffness of each ring is studied and the results revealed a typical trend of decreasing stiffness in ISSFD ring with the increase in groove angle and hence the overlapping angle of grooves. The static stiffness parametric studies has resulted in developing an ideal profile of ISSFD ring having six grooves that exhibited axisymmetric pattern of circumferential variation of stiffness. When used in a space constrained intershaft bearing plane of a typical two spool gas turbine engine, the ideal ISSFD ring profile would exhibit the best damping performance. 
 Keywords: Inter Shaft Squeeze Film Damper (ISSFD), Gas Turbine Engine, Static stiffness, two spools, grooves.

Hardware implementation of the diagnostic system of a car electric drive

Operational monitoring of vehicle diagnostic parameters allows you to timely establish the fact of a malfunction, localize the location of damage and affect the drive system to avoid an emergency situation. The purpose of research at this stage is the selection of traction electronic devices and the synthesis of the design of an information-measuring complex for monitoring the diagnostic parameters of a car traction electric drive system. The hardware implementation of the measuring complex, in general, involves the solution of several problems: the choice of the type of current sensor; integration of the sensor into the battery; building a spectrum analyzer structure; selection of digital signal processing system configuration; constructive and electrical binding of the complex to the object of diagnosis. As a diagnostic parameter to assess the technical condition of the traction electric drive, the spectral composition of the periodic function of the battery current is considered. To measure the current at the stage of a physical experiment in the power supply circuit, it is necessary to determine the type of the non-contact current sensor. For technological reasons, annular sensor designs are appropriate to use in integrated measuring channels, the clamped ones - in external connection systems. In the first case, the requirements for the design and technical characteristics, an analog current sensor type CSLA2DG ring design was selected. In the second case, universal current meters of industrial designs with analog, digital or radio frequency output can be used. For linking the current sensor to the power supply circuit of the traction electric drive, the proposed designs of the technological jumper of the battery are proposed. The choice of the type of spectrum analyzer is determined by the method of its application (development stage, system configuration). At the stage of building the knowledge base of an expert system, several options (hardware, software, hardware and software) of low-frequency spectrum analyzers for various purposes, such as equalizers, sound level meters, vibration analyzers, were considered. Based on the selected devices of the measuring channel, two configurations of the diagnostic system were synthesized – integrated into the traction electric drive and external connection. Several options of connection (models) of current meters with an expert system, which is implemented in the environment of universal computer facilities, are determined.Keywords: electric drive; Hall sensor; high-voltage battery; spectrum analyzer; diagnostic system.

Modeling of spin-orbital dynamics in a storage ring

Two distinct storage ring designs have been proposed for the deuteron Electric Dipole Moment (dEDM) search experiment: a Frozen Spin, and a Quasi-Frozen Spin ring. The FS-ring allows for the most accurate measurement, but the continuous fulfilment of the FS condition is unrealizable. The QFS design relaxes the condition to only hold on average, at a slight cost of precision. [1] The goal of the present work is to investigate which design is preferable for the attainment of the target precision. This task requires one to model the spinorbital dynamics of the beam in both rings.

Sensitivity Analyses of All-Electric Storage Ring Designs

Sensitivity Analyses of All-Electric Storage Ring Designs

Comparison of Passive 2-D and 3-D Ring Arrays for Medical Telemetry Focusing

In this letter, we investigate the performance of subdermal ring designs for focusing electromagnetic fields inside the body for next-generation implantable medical devices. We will concentrate on the Medical Implant Communications Service band $(\text{402} \text{--}\text{405 MHz})$ , but prepare our design at $\text{433 MHz}$ , the nearest Industrial, Scientific, Medical band. The designs include two-dimensional (2-D or coplanar) and 3-D arrays of circular rings and 3-D arrays of ellipses. The 3-D ring and ellipse arrays focus the fields more effectively than 2-D designs, through constructive coupling between the rings. Compared to the case where no rings are used, the power available from the focused field 20 mm below the skin is 2.24 times and 3.12 times larger if 3-D rings and 3-D ellipses are utilized, respectively. Rings can be used for circular polarization applications, and ellipses are more optimal for linear polarization applications.

A Qualitative Systematic Review of Women's Experiences Using Contraceptive Vaginal Rings: Implications for New Technologies.

Vaginal rings are available for contraception and hormone replacement, and are being developed as HIV/STD or multipurpose prevention technologies. A comprehensive understanding of women's expectations of and experiences with rings is urgently needed to inform product development and to optimize ring use. Three databases (PubMed, Global Health and CINAHL) were searched for English-language, peer-reviewed articles published between January 1996 and November 2017 that reported qualitative data on barriers to and facilitators of use of female-controlled contraceptive methods. Data on study methods, findings and conclusions pertaining to contraceptive rings were extracted, organized and analyzed. Twenty-six articles, all published since 2008, met the inclusion criteria. Seven studies focused largely or entirely on rings (and involved current, former or potential users), while the others focused on other contraceptive methods but included ring-specific data. Familiarity with the ring was low, and women commonly had initial concerns about the method-often related to insertion and removal, cleanliness and discomfort with touching their vagina-that were typically overcome over time. Other major themes were issues related to ring use and discontinuation, the importance of ring-related properties and characteristics, and considerations related to sexual partners and health care providers. Qualitative data have the potential to inform ring design and promotion. Future research should further explore women's expectations and experiences with the ring, the value of involving male partners in ring evaluation, and evaluation of interventions to improve patient-provider communication concerning ring choice and use.

The Golden Proportion in the scallop geometry of normal mitral valves. When nature plays with jigsaw puzzles.

The Golden Proportion is a particular geometric ratio between two segments. It results in an irrational number, commonly rounded to 1.618, or 0.618, and showing unique geometrical/mathematical properties. Its presence has been documented in a huge amount of natural settings, as well as the human body and the heart. In light of a previous research of ours, about its presence in the Coaptation Triangle, we investigated the dimensions of both mitral leaflets in healthy mitral valves and then compared our results to literature data, in order to search whether this proportional pattern could be extended to other valve aspects. Forty-one adults, with healthy mitral valves, underwent 2D echocardiography. Adequate long-axis three-chamber view images were chosen, at mid-diastole, where the central scallop of both the anterior and posterior leaflets (A2 and P2, respectively) could be well identified and measured. We then investigated these measurements, calculating their ratio and comparing our findings to literature data on normal mitral anatomy. The ratio between the two scallop heights appeared very close to the Golden Ratio. Literature data supported our results and, apparently, showed the mitral leaflets to be like a jigsaw puzzle of components highly interconnected each other with an extremely simple geometry, based on the Golden Proportion. The Golden Proportion looks to determine the geometry of normal mitral scallops. Studying such a pattern of anatomical proportions could improve surgical techniques for conservative surgery, as well as innovate the design of mitral repair rings and valve prostheses.

Evaluation of mixing performance for the industrial-scale radial multiple jets-in-crossflow mixing structure

The radial multiple jets-in-crossflow mixing structure (RMJCMS) is extensively used in industrial manufacture. In this research, flow behavior induced by an industrial-scale RMJCMS is investigated via computational fluid dynamics considering the example of the mixing of TiCl4 and O2 in the chloride process. The flow features of RMJCMS are accurately captured through simulation. The momentum ratio and size distribution of jet holes are notable elements for controlling the mixing performance. For an injection ring with single-diameter jet holes, the optimal momentum ratio was 3.2. To improve the mixing performance of RMJCMS, a design strategy that maximized the effect of convective mixing by modifying the distribution of the jet hole diameters was proposed based on the simulation results to guide the design of the injection ring. With the designed injection ring, the dimensionless mixing distance decreased by 50% compared with the equal-hole case, validating the effectiveness of the design strategy.

Design and dynamic studies for a compact storage ring to generate gamma-ray light source based on Compton backscattering technique

As the development of nuclear physics and atomic sciences progresses, monochromatic and high-flux gamma-ray light sources are highly demanded by many experiments in these fields. We have designed a compact storage ring for gamma-ray source generation based on the Compton backscattering technique. The energy range of the electron beam stored in the ring will be from 500 to 800 MeV, with the capability of generating a gamma ray with an energy range from about 4 to 10 MeV. The maximum energy loss for an electron could be more than 1% for one scattering event, which could have a significant impact on electron beam dynamics. To study this impact, a 6D macroparticle tracking code has been developed by including the Compton scattering, damping, quantum excitation, and synchrotron radiation in the storage ring. The equilibrium states have been studied with this code, and the results show good agreement with theoretical predictions. The electron beam loss rate induced by Compton scattering has also been investigated by varying the input laser beam parameters. This study allows us to optimize the storage ring operation for a stable, high-flux, and narrow-bandwidth gamma-ray beam generation.

More Pieces of Ancient than Recent Theoretical Minimal Proto-tRNA-Like RNA Rings in Genes Coding for tRNA Synthetases.

Theoretical minimal RNA rings were designed to mimick life's primordial RNAs by forming stem-loop hairpins and coding once for each of the 20 amino acids, a start and a stop codon. At most 25 22-nucleotide long RNA rings follow these criteria. These align well with a consensus tRNA sequence, predicting for each RNA ring an anticodon and an associated cognate amino acid. Hypotheses on cognate amino acid order of inclusion in the genetic code produce evolutionary ranks for theoretical RNA rings. This evolutionary hypothesis predicts that pieces of RNA rings with more ancient cognate amino acid should be more frequent in modern genes than those from RNA rings with late cognate amino acids. Analyses of genes for tRNA synthetases, among the most ancient proteins, from archaeal, bacterial, eukaryote and viral superkingdoms overall confirm these predictions, least for tRNA synthetases with early cognate amino acids and for the neogene-enriched genome of the giant virus Tupanvirus. Hence early tRNA synthetase genes and late RNA rings evolved separately. Results indicate that RNA rings and tRNA synthetases with the same cognate amino acid are less separated for relatively recent cognate amino acids, suggesting that over evolutionary time the components of the molecular apparatus became more integrated, perhaps in cell-like membrane-bound systems. Results confirm that theoretical considerations in the design of minimal RNA rings recreated RNAs close to the actual primordial RNA population that produce genes by accretion, and confirm the hypothesis of homology of minimal RNA rings with tRNAs and their proto-tRNA status.

Optimization Design on Active Guard Ring to Improve Latch-Up Immunity of CMOS Integrated Circuits

A new optimization design of an active guard ring has been proposed to improve latch-up immunity of CMOS integrated circuits and been successfully verified in a 0.18- $\mu \text{m}$ 1.8-/3.3-V CMOS technology. Codesigned with the on-chip electrostatic discharge (ESD) protection devices (gate-ground nMOS and gate-VDD pMOS) equipped at the input–output (I/O) pad, the overshooting/undershooting trigger current during latch-up test can be conducted away through the turned-on channels of the ESD protection MOSFET’s to the power rails ( ${V}_{\textsf {DD}}$ or ${V}_{\textsf {SS}}$ ). Therefore, the trigger current injecting from the I/O devices (that directly connected to the I/O pad) through the substrate to initiate the latch-up occurrence at the internal circuit blocks can be significantly reduced. Thus, the latch-up immunity of the whole chip can be effectively improved under the same placement distance between the I/O cells and the internal circuit blocks. The new proposed design is a cost-efficient solution to improve latch-up immunity and also to mention good ESD robustness of the I/O cells.

Finite Angle Multichannel Space Slip Ring Design

According to the working environment characteristics and technical requirements of the finite angle conductive slip ring, a kind of finite angle slip ring with limited angle is designed by using flexible circuit board to transmit power and control signals between two relative rotating mechanisms. Flexible circuit boards are rotated between the inner and outer ring. The inner and outer rings are designed as wedge-shaped stepped structures, which greatly reduce the friction torque of the finite angle slip rings. This paper focuses on the structural design and performance parameters test of finite angle finite angle slip ring, verifying that the slip ring has the advantages of light, small, low friction torque, high reliability and so on.

Experimental and Monte-Carlo characterization of the novel compact ionization chamber PTW 31023 for reference and relative dosimetry in high energy photon beams

IntroductionThe aim of the present work is to perform dosimetric characterization of a novel vented PinPoint ionization chamber (PTW 31023, PTW-Freiburg, Germany). This chamber replaces the previous model (PTW 31014), where the diameter of the central electrode has been increased from 0.3 to 0.6mm and the guard ring has been redesigned. Correction factors for reference and non-reference measurement conditions were examined. Materials and methodsMeasurements and calculations of the correction factors were performed according to the DIN 6800-2. The shifts of the effective point of measurement (EPOM) from the chamber's reference point were determined by comparison of the measured PDD with the reference curve obtained with a Roos chamber. Its lateral dose response functions, which act according to a mathematical convolution model as the convolution kernel transforming the dose profile D(x) to the measured signal M(x), have been approximated by Gaussian functions with standard deviation σ. Additionally, the saturation correction factors kS have been determined using different dose-per-pulse (DPP) values. The polarity effect correction factors kP were measured for field sizes from 5cm×5cm to 40cm×40cm. The influence of the diameter of the central electrode and the new guard ring on the beam quality correction factors kQ was studied by Monte-Carlo simulations. The non-reference condition correction factors kNR have been computed for 6MV photo beam by varying the field size and measurement depth. Comparisons on these aspects have been made to the previous model. ResultsThe shifts of the EPOM from the reference point, Δz, are found to be −0.55 (6MV) and −0.56 (10MV) in the radial orientation and −0.97mm (6MV) and −0.91mm (10MV) in the axial orientation. All values of Δz have an uncertainty of 0.1mm. The σ values are 0.80mm (axial), 0.75mm (radial lateral) and 1.76mm (radial longitudinal) for 6MV photon beam and are 0.85mm (axial), 0.75mm (radial lateral) and 1.82mm (radial longitudinal) for 15MV photon beam. All σ values have an uncertainty of 0.05mm. The correction factor kS was found to be 1.0034±0.0009 for the PTW 31014 chamber and 1.0024±0.0007 for the PTW 31023 chamber at the highest DPP (0.827mGy) investigated in this study. Under reference conditions, the polarity effect correction factor kP of the PTW 31014 chamber is 1.0094 and 1.0116 for 6 and 10MV respectively, while the kP of the PTW 31023 chamber is 1.0005 and 1.0013 for 6 and 10MV respectively, all values have an uncertainty of 0.002. The kP of the new chamber also exhibits a weaker field size dependence. The kQ values of the PTW 31023 chamber are closer to unity than those of the PTW 31014 chamber due to the thicker central electrode and the new guard ring design. The kNR values of the PTW 31023 chamber for 6MV photon beam deviate by not more than 1% from unity for the conditions investigated. DiscussionsCorrection factors associated with the new chamber required to perform reference and relative dose measurements have been determined according to the DIN-protocol. The correction factor kS of the new chamber is 0.1% smaller than that of the PTW 31014 at the highest DPP investigated. Under reference conditions, the correction factor kP of the PTW 31023 chamber is approximately 1% smaller than that of the PTW 31014 chamber for both energies used. The dosimetric characteristics of the new chamber investigated in this work have been demonstrated to fulfil the requirements of the TG-51 addendum for reference-class dosimeters at reference conditions.

Hybrid ring design in the storage-ring proton electric dipole moment experiment

A new, hybrid design is proposed to eliminate the main systematic errors in the frozen spin, storage ring measurement of the proton electric dipole moment. In this design, electric bending plates steer the particles, and magnetic focusing replaces electric. The magnetic focusing should permit simultaneous clock-wise and counter-clock-wise storage to cancel systematic errors related to the out-of-plane dipole electric field. Errors related to the quadrupole electric fields can be eliminated by successive runs of magnetic focusing with different strengths.

3466 Innovative 3D Printed Intravaginal Rings: Developing AnelleO PRO, the First Intravaginal Ring for Infertility

OBJECTIVES/SPECIFIC AIMS: The study aims to develop and test a biocompatible 3D-printed IVRs for the mechanical and release properties of a model drug, β-estradiol, then translate these methods to the target drug, progesterone. The goals include demonstrating decoupling of mechanical and release properties of the rings, release profiles driven by geometry and efficacy in sheep animal models to evaluate device safety. METHODS/STUDY POPULATION: A novel 3D-printing platform, continuous liquid interface production (CLIP), pioneered by Carbon, enables the fabrication of complex designs on a timescale that is amenable to manufacturing. The process utilizes computational-aided design (CAD), specifying shape and geometry, which is recreated via a photopolymerization process. IVRs are fabricated with CLIP using a biocompatible resin at a rate of approximately 15 min. per ring. Rings were fabricated and assessed for the release of a model drug, β-estradiol. The process was then translated to the target drug, progesterone. Rings were evaluated for radial compression and in vitro release in simulated vaginal fluid (SVF). RESULTS/ANTICIPATED RESULTS: Intravaginal rings (IVRs) were designed and fabricated to be geometrically complex in an effort to control release. Ring geometry and subsequent pore size was achieved through the use of unit cells. Several design parameters were explored including unit cell type, size, and band presence in two resins of differing mechanical properties. Through design, a wide range of radial compressive properties were achieved which spanned values covered by commercially available rings. The release of β-estradiol in SVF was found to span 57 – 115 days and resulted in near or complete release of the total loaded drug. Changing the internal geometric design of the ring was found to have minimal influence on the compression properties, thus the mechanical and release characteristics of the rings were largely decoupled. DISCUSSION/SIGNIFICANCE OF IMPACT: This is a novel approach to the design and fabrication of intravaginal rings for the treatment of infertility. The use of CAD and the decoupling of release from mechanical properties allows for us to move away from the one-size one-dose fits all approach to IVRs.

The Optimal Design of Field Ring for Reliability and Realization of 3.3 kV Insulated-Gate Bipolar Transistor Power Semiconductor

This research was about field ring for 3.3 kV planar gate power IGBT. Therefore, we designed optimal field ring for 3.3 kV power IGBT and we analyzed the electrical characteristics of 3.3 kV planar gate power IGBT according to parameters of field ring. Based on this background, we obtained 3.3 kV high breakdown voltage and 2.9 V on state voltage drop for 3.3 kV planar gate power IGBT. To obtain high breakdown voltage, we confirm that the counts of field ring were 23. And we obtained optimal parameters. The gap distance between field rings to field ring was 13 μm and the width of field ring was 5 μm. This design technology will be adapt field stop IGBT and super junction IGBT. Thyristor device for power conversion switch will be replaced to super high voltage power IGBT.

6-in Dual-Gate Ring Commutated Thyristor for DC Circuit Breakers

DC circuit breakers (DCBs) are crucial components in dc power systems. The ultralow operating frequency of the DCBs enables the use of gate-commutated thyristors (GCTs) in the DCBs. This paper proposed a 6-in dual-gate ring commutated thyristor (DGRCT) for the DCB applications. The wafer and package designs of the DGRCT are first presented and discussed, analyzing the principles of the current commutation in the DGRCTs. Subsequently, a DGRCT prototype is fabricated, and experiments are conducted to measure the inductance along the current commutation loop (CCL) of the prototype DGRCT. Finally, a large current interruption experiment is conducted. The results show that the prototype DGRCT reduced the parasitic inductance within the CCL by at least 20% compared to conventional GCTs with single-gate ring design. The maximum current interruption capacity of the prototype DGRCT is no less than 12 kA at T = 300 K, which approaches the fault current interruption requirement in DCB applications for both transmission and distribution levels of dc power systems.

Vaginal rings with exposed cores for sustained delivery of the HIV CCR5 inhibitor 5P12-RANTES

Antiretroviral-releasing vaginal rings are at the forefront of ongoing efforts to develop microbicide-based strategies for prevention of heterosexual transmission of the human immunodeficiency virus (HIV). However, traditional ring designs are generally only useful for vaginal administration of relatively potent, lipophilic, and small molecular weight drug molecules that have sufficient permeability in the non-biodegradable silicone elastomer or thermoplastic polymers. Here, we report a novel, easy-to-manufacture ‘exposed-core’ vaginal ring that provides sustained release of the protein microbicide candidate 5P12-RANTES, an experimental chemokine analogue that potently blocks the HIV CCR5 coreceptor. In vitro release, mechanical, and stability testing demonstrated the utility and practicality of this novel ring design. In a sheep pharmacokinetic model, a ring containing two ¼-length excipient-modified silicone elastomer cores – each containing lyophilised 5P12-RANTES and exposed to the external environment by two large windows – provided sustained concentrations of 5P12-RANTES in vaginal fluid and vaginal tissue between 10 and 10,000 ng/g over 28days, at least 50 and up to 50,000 times the reported in vitro IC50 value.

Design and optimization of a multi-bend achromat lattice for 3.5 GeV synchrotron storage ring

In the past decades, the optimized design of light source array by use of multi-bend achromat has been considered to achieve high-quality photon beam for fundamental researches in different areas of science and technology. In this paper, we investigate a lattice design for a low emittance storage ring with intermediate energy of 3.5 GeV . We present the design results in detail for a five-bend achromat lattice with an emittance of 230 pm-rad, appropriate dynamic aperture, high brilliance photons near soft X-ray diffraction limited, the total lifetime of 11 hours and circumference of 448 m contains 20 straight sections of 6.1 meters in length. The results of closed orbit correction and misalignments errors on the dynamic aperture were also presented. The lattice provides sufficient dynamic aperture after closed orbit distortion correction. Furthermore, the variation of the emittance due to coupling and intra-beam scattering (IBS) effect has been calculated as a function of the energy and length of the bunch. Our designed storage ring shows an optimized five-bend achromat lattice for intermediate light sources.

Valve Operability During a Fire

Fire and explosion are a major cause of concern for refinery, gas processing, petrochemical, and gas installations. The safest way to deal with a fire is to prevent it. However, fire prevention strategies are not always successful, and fires can happen. Therefore, valves should be designed and tested to be fire-safe. This paper reviews valve design features that can help prevent fires, including secondary sealing between the ball and body in case of losing a soft seat, a graphite fire-safe ring design for stem and seat sealing, antistatic devices, and antistatic tests to ensure that the valve is fire-safe. In addition to design considerations, a fire-safe design should be validated through tests defined in standards such as API 607, API RP 6FA, and ISO 10497. The API RP 6FA tests reviewed in this paper include seven tests that check the operability of the valve from closed to open position. A case study was done to prove the operability of a fail close 38″ pipeline ball valve on an oil export pipeline in case of fire during the first 20 s from the open to the closed position. Thermal analysis on the body of the valve proved that there was no thermal expansion inside the valve after 150 s of fire. Additionally, the maximum radial displacement on the valve body after 150 s of fire was 0.34 mm which is negligible. Thus, the valve thermal expansion did not disturb the operation of the valve after 20 s.