Pancake Geometry Research Articles

MP38-09 MAGNETIC INDUCTION WAND DESIGN FOR NOVEL PENILE PROSTHESIS

You have accessJournal of UrologyCME1 May 2022MP38-09 MAGNETIC INDUCTION WAND DESIGN FOR NOVEL PENILE PROSTHESIS Shannon Roney, Michael Mendoza, Maya McKenzie, Gail Baura, Brian Le, Kevin McVary, and Alberto Colombo Shannon RoneyShannon Roney More articles by this author , Michael MendozaMichael Mendoza More articles by this author , Maya McKenzieMaya McKenzie More articles by this author , Gail BauraGail Baura More articles by this author , Brian LeBrian Le More articles by this author , Kevin McVaryKevin McVary More articles by this author , and Alberto ColomboAlberto Colombo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002592.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We developed a novel shape memory alloy prosthesis using a lasercut Nitinol extruded tube that expands and becomes rigid when heat activated thus simulating an erection. We now describe magnetic induction activation of the prosthesis in a touchless fashion. We developed an external induction device (“wand”) using a power resonator circuit that creates an oscillating current across custom-made induction coils. The wand can be waved around the penis, activating the prosthesis and simulating an erection. We compared the wand with an off-the-shelf inducer, Miniductor-II (1000 Watts, positive control). METHODS: A novel external wand was designed with microcontroller control. Several safety features were added to protect against excess power (temperature and current) discharge, including a current limiting circuit. The system is powered by 4 rechargeable 3.7 V lithium-ion batteries that make it portable and light. A testbench, with angle and distance sensors, a camera and image analysis, was used to measure the deformation of the prosthesis over time. Prosthesis deformation was evaluated by calculating the deflection angle of the prosthesis and the decreasing subtended area. Helicoidal coil and a pancake coil geometry were tested. Different parameters were considered such as the distance and angulation between the wand’s coil and the prosthesis. RESULTS: The novel wand activated the prosthesis in a less than 30 seconds by increasing the temperature from 27C to 45C, reducing the subtended area from 4000mm2 to less than 2000mm2 and the angle of the prosthesis near the coil to 0°. The results were comparable to the results with the control (Miniductor-II), with less power (44.4 Watts) required. Using Design of Experiments statistical analysis, the pancake coil geometry results were more stable and independent of distance and angle. CONCLUSIONS: The induction heating wand activates the prosthesis using much lower power than the Miniductor-II and a timer that prevents excess temperature, thus increasing safety. The novel wand uses rechargeable batteries instead of cord-connection to a wall outlet, making it portable and user friendly. The pancake coil geometry provided more consistent results that are independent from the coil/prosthesis distance and angle, making it more user friendly. Source of Funding: Uronext LLC © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e621 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shannon Roney More articles by this author Michael Mendoza More articles by this author Maya McKenzie More articles by this author Gail Baura More articles by this author Brian Le More articles by this author Kevin McVary More articles by this author Alberto Colombo More articles by this author Expand All Advertisement PDF DownloadLoading ...

A 3D printed modular phantom for quality assurance of image-guided small animal irradiators: Design, imaging experiments, and Monte Carlo simulations.

The goal of this work was to develop and test a cylindrical tissue-equivalent quality assurance (QA) phantom for micro computed tomography (microCT) image-guided small animal irradiators that overcomes deficiencies of existing phantoms due to its mouse-like dimensions and composition. The 8.6-cm-long and 2.4-cm-diameter phantom was three-dimensionally (3D) printed out of Somos NeXt plastic on a stereolithography (SLA) printer. The modular phantom consisted of four sections: (a) CT number evaluation section, (b) spatial resolution with slanted edge (for the assessment of longitudinal resolution) and targeting section, (c) spatial resolution with hole pattern (for the assessment of radial direction) section, and (d) uniformity and geometry section. A Python-based graphical user interface (GUI) was developed for automated analysis of microCT images and evaluated CT number consistency, longitudinal and radial modulation transfer function (MTF), image uniformity, noise, and geometric accuracy. The phantom was placed at the imaging isocenter and scanned with the small animal radiation research platform (SARRP) in the pancake geometry (long axis of the phantom perpendicular to the axis of rotation) with a variety of imaging protocols. Tube voltage was set to 60 and 70kV, tube current was set to 0.5 and 1.2mA, voxel size was set to 200 and 275μm, imaging times of 1, 2, and 4min were used, and frame rates of 6 and 12 frames per second (fps) were used. The phantom was also scanned in the standard (long axis of the phantom parallel to the axis of rotation) orientation. The quality of microCT images was analyzed and compared to recommendations presented in our previous work that was derived from a multi-institutional study. Additionally, a targeting accuracy test with a film placed in the phantom was performed. MicroCT imaging of the phantom was also simulated in a modified version of the EGSnrc/DOSXYZnrc code. Images of the resolution section with the hole pattern were acquired experimentally as well as simulated in both the pancake and the standard imaging geometries. The radial spatial resolution of the experimental and simulated images was evaluated and compared to experimental data. For the centered phantom images acquired in the pancake geometry, all imaging protocols passed the spatial resolution criterion in the radial direction (>1.5lp/mm @ 0.2MTF), the geometric accuracy criterion (<200μm), and the noise criterion (<55HU). Only the imaging protocol with 200-μm voxel size passed the criterion for spatial resolution in the longitudinal direction (>1.5lp/mm @ 0.2MTF). The 70-kV tube voltage dataset failed the bone CT number consistency test (<55HU). Due to cupping artifacts, none of the imaging protocols passed the uniformity test of <55HU. When the phantom was scanned in the standard imaging geometry, image uniformity and longitudinal MTF were satisfactory; however, the CT number consistency failed the recommended limit. A targeting accuracy of 282 and 251μm along the x- and z-direction was observed. Monte Carlo simulations confirmed that the radial spatial resolution for images acquired in the pancake geometry was higher than the one acquired in the standard geometry. The new 3D-printed phantom presents a useful tool for microCT image analysis as it closely mimics a mouse. In order to image mouse-sized animals with acceptable image quality, the standard protocol with a 200-μm voxel size should be chosen and cupping artifacts need to be resolved.

Performance of layer wound epoxy-impregnated coils made from a multifilamentary cable of exfoliated YBCO

The performance and reliability of magnets made from second generation (2G), exfoliated, YBCO conductors are highly improved by use of narrow, stacked, multifilamentary cable instead of a single wide tape. This paper reports on tests of five mini-coils wound from 2.4 mm wide ExoCable™, which is comprised of eight, stacked, exfoliated, YBCO filaments. The filaments are coupled electrically through a re-flow process, which results in enhanced electrical connectivity between the adjacent layers. The coils were tested at 77 K (up to 500 A) in liquid nitrogen and at 22 K (up to 700 A) in a conduction-cooled mode. The cable carries 500 A critical current at 77 K. A six-layer coil wound from 10.5 m of the cable, the largest coil created in the study, demonstrates a critical current of 280 A at 77 K at 0.4 T magnetic field on the winding. The coils were fully impregnated with Stycast 1266 and Henkel W19 low-viscosity epoxies. Repeated thermal cycling, to 77 and 22 K, does not degrade the coil’s performance. The cable AC loss and the coil winding magnetization are compared with the traditional 2G wide tape pancake geometry at 77 K. We observe a five times reduction of the winding magnetization when the 12 mm tape is replaced by a 2.4 mm cable, which is explained by the smaller magnetic moment of the cable winding. The field hysteresis profiles recorded at 22 and 77 K are presented to demonstrate the effect of the operation temperature on the winding magnetization. A finite element analysis of the winding magnetization shows a good agreement between the experimentally measured trapped field value, and the critical state model prediction. Finally, we discuss the stability of an ExoCable™ coil in a conduction-cooled operation.

Geometry-induced modification of fluctuation spectrum in quasi-two-dimensional condensates

We report the structural transformation of the low-lying spectral modes, especially the Kohn mode, from radial to circular topology as harmonic confining potential is modified to a toroidal one, and this corresponds to a transition from simply to multiply connected geometry. For this we employ the Hartree–Fock–Bogoliubov theory to examine the evolution of low energy quasiparticles. We, then, use the Hartree–Fock–Bogoliubov theory with the Popov approximation to demonstrate the two striking features of quantum and thermal fluctuations. At T = 0, the non-condensate density due to interaction induced quantum fluctuations increases with the transformation from pancake to toroidal geometry. The other feature is, there is a marked change in the density profile of the non-condensate density at finite temperatures with the modification of trapping potential. In particular, the condensate and non-condensate density distributions have overlapping maxima in the toroidal condensate, which is in stark contrast to the case of pancake geometry. The genesis of this difference lies in the nature of the thermal fluctuations.

Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation

The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal (‘tubular’ geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal (‘pancake’ geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry, respectively.

High Temperature Superconducting (HTS) Coils for a Compact Spherical Tokamak

High temperature superconductors (HTSs) have the potential to impact the future development of superconducting applications for research magnets in physical sciences and industrial products. A compact spherical tokamak of major radius 25 cm has been designed and engineered using the second generation HTS material, REBCO tapes. It was developed with the primary objective to test out the feasibility of a fully superconducting device made entirely from HTS materials and hence be the first tokamak to demonstrate the practicality of this new medium operating at temperatures above 4.2 K. The tokamak has 6-D shaped toroidal field coils, and two poloidal field coils, each of which is wound in a pancake geometry. Each coil is made in one continuous winding and the coils are assembled together. Results of initial coils and magnet cooling and energisation will be presented.

Active space debris removal by a hybrid propulsion module

During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to a total tally of approximately 7000 metric tons. Now, most of the cross-sectional area and mass (97% in LEO) is concentrated in about 4600 intact objects, i.e. abandoned spacecraft and rocket bodies, plus a further 1000 operational spacecraft. Simulations and parametric analyses have shown that the most efficient and effective way to prevent the outbreak of a long-term exponential growth of the catalogued debris population would be to remove enough cross-sectional area and mass from densely populated orbits. In practice, according to the most recent NASA results, the active yearly removal of approximately 0.1% of the abandoned intact objects would be sufficient to stabilize the catalogued debris in low Earth orbit, together with the worldwide adoption of mitigation measures. The candidate targets for removal would have typical masses between 500 and 1000kg, in the case of spacecraft, and of more than 1000kg, in the case of rocket upper stages. Current data suggest that optimal active debris removal missions should be carried out in a few critical altitude–inclination bands. This paper deals with the feasibility study of a mission in which the debris is removed by using a hybrid propulsion module as propulsion unit. Specifically, the engine is transferred from a servicing platform to the debris target by a robotic arm so to perform a controlled disposal. Hybrid rocket technology for de-orbiting applications is considered a valuable option due to high specific impulse, intrinsic safety, thrust throttle ability, low environmental impact and reduced operating costs. Typically, in hybrid rockets a gaseous or liquid oxidizer is injected into the combustion chamber along the axial direction to burn a solid fuel. However, the use of tangential injection on a solid grain Pancake Geometry allows for more compact design of the propulsion unit. Only explorative tests were performed in the past on this rocket configuration, which appears to be suitable as de-orbiting system of new satellites as well as for direct application on large debris in the framework of a mission for debris removal. The paper describes some critical aspects of the mission with particular concern to the target selection, the hybrid propulsion module, the operations as well as the systems needed to rendezvous and dock with the target, and the disposal strategy.

Vortex-antivortex wavefunction of a degenerate quantum gas

A mechanism of a pinning of the quantized matter wave vortices by optical vortices in a specially arranged optical dipole traps is discussed. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum and form the "antiferromagnet"-like matter waves. The separable Hamiltonian for matter waves in pancake trapping geometry is proposed and 3D-wavefunction is factorized in a product of wavefunctions of the 1D harmonic oscillator and 2D vortex-antivortex quantum state. The 2D wavefunction's phase gradient field associated via Madelung transform with the field of classical velocities forms labyrinth-like structure. The macroscopic quantum state composed of periodically spaced counter-rotating BEC superfluid vortices has zero angular momentum and nonzero rotational energy.

Cold polar molecules in two-dimensional traps: Tailoring interactions with external fields for novel quantum phases

We discuss techniques to engineer effective long-range interactions between polar molecules using external static electric and microwave fields. We consider a setup where molecules are trapped in a two-dimensional pancake geometry by a far-off-resonance optical trap, which ensures the stability of the dipolar collisions. We detail how to modify the shape and the strength of the long-range part of interaction potentials, which can be utilized to realize interesting quantum phases in the context of cold molecular gases.

Influence of Flour Chlorination and Ingredient Formulation on the Quality Attributes of Pancakes

ABSTRACTSoft wheat flour is commonly chlorinated in North America for the production of cakes and pancakes. The oxidative properties of chlorine gas cause chemical modifications to flour components that enhance processing and end‐use functionality of the intended food products. The objectives of this study were 1) to compare how untreated and chlorine‐treated commercial soft wheat flour perform in a standard pancake formulation and 2) to compare how the individual ingredients in a standard pancake formulation influence quality attributes of pancakes made with untreated as well as chlorine‐treated commercial soft wheat flour. Two portions of the same soft wheat flour, one chlorinated and the other un‐chlorinated, were used to study the effects of flour chlorination on batter viscosity, geometry, and texture quality attributes of pancakes. Commercial pancake formula ingredients were evaluated at different concentrations for their individual influence on quality attributes of pancakes. Differences in means (ANOVA) were used to evaluate the influence of the sources of pancake quality variation. The results indicate that flour chlorination had a significant influence on pancake batter viscosity, geometry, and texture, with chlorinated flour producing a more viscous batter, a larger and thicker pancake that was softer, more cohesive and resilient. The evaluation of a wide range of formula ingredient concentrations indicated that none could wholly substitute for chlorination. Individual ingredients did dramatically influence pancake batter viscosity, geometry, and texture, especially soy flour, dextrose, and leavening agents. However, sucrose and shortening had nonsignificant influences on the end‐use quality of both chlorinated and unchlorinated pancakes.

16 tesla Nb/sub 3/Sn dipole development at Texas A&amp;M University

A 16 Tesla Nb/sub 3/Sn block-coil dual dipole is being developed to extend the available field strength for future hadron colliders. The design incorporates several novel features. Current programming of 3 independent coil elements is used to control all multipoles over a 20:1 dynamic range of dipole field. Stress management, comprising a lattice of ribs and plates integrated into the coil structure, is used to distribute preload and Lorentz forces so that the stress in the coil never exceeds 100 MPa. Distributed cooling, utilizing spring elements in each coil block, intercepts heat generated by synchrotron radiation and beam losses. Rectangular pancake coil geometry accommodates simple fabrication and direct preload in the direction of Lorentz forces. The bore diameter can be optimized for collider requirements (2.5 cm for 50 TeV/beam vs, 5 cm for 8 TeV/beam), so that a 16 Tesla block-coil dipole for 50 TeV/beam requires the same amount of superconductor/TeV as the 8.5 Tesla LHC dipole for 8 TeV/beam. A first model of the dipole is currently being built.

EVALUATION AND MANAGEMENT OF THIN OIL COLUMN RESERVOIRS IN AUSTRALIA

Thin oil columns represent a common and important class of hydrocarbon reserve which are notoriously difficult to evaluate and produce. This paper provides case studies of examples of these reservoirs in Australia and summarises the production methods, well performance and recovery efficiencies.Thin oil column reservoirs are defined here as reservoirs which will cone both water and gas when produced at commercial rates. The oil zone can have a pancake or rim geometry. Examples within Australia include Bream and Snapper (Gippsland Basin), South Pepper and Chervil (Carnarvon Basin), Chookoo (Eromanga Basin) and Taylor (Surat Basin).Parameters which are particularly important in defining the performance of these reservoirs are: horizontal and vertical permeability, column height, stratigraphie dip, well spacing, and oil viscosity. High horizontal permeability is more critical than in other reservoir types as it controls the effectiveness of gravitational forces in opposing coning and other unwanted flows by reducing pressure gradients. Low vertical permeability mitigates coning but can limit across strike drainage in dipping strata. Oil viscosity is also particularly important, even when the mobility ratio is favourable, as it controls the gas/oil ratio and water cut during coning.As coning (by definition) is inevitable the key production issue is gas cap management. The main options are:Limit gas coning by controlling completion depth and production rates.Allow gas cap shrinkage and 'chase' the oil column upwards via recompletions.Reinject gas to control gas-oil contact position.For the latter two options in particular, ultimate reserves are a strong function of the capacity of the installed production facilities, especially offshore, where fixed operating costs are high. When gas cap management is not compromised, reserves increase with higher total fluid withdrawal rates. Examples of the various gas cap management and production strategies are included.Both horizontal (South Pepper, Bream) and conventional (Chookoo, Taylor) completion techniques have been applied to thin oil column reservoirs in Australia. Horizontal completions can increase productivity, mitigate coning and increase the well drainage areas (particularly if drilled across dip in heterogeneous reservoirs). However, horizontal completions are particularly vulnerable to poor cement jobs, natural fractures and undesirable fluid contact movements.A variety of other completion techniques have been tried worldwide in thin oil columns with mixed success. These include multiple completions in the water, oil and/or gas to allow separate production, and injection of fluids to make permeability barriers or alter relative permeability.A number of scaling rules are included to assist in using offset field data for evaluation of thin oil column reservoirs. Improved understanding of these complex reservoirs will maximise their economic potential.

Observations on the Application of the k-E Model to Internal Combustion Engine Flows

Abstract Multi-dimensional flow calculations o f a motored, pancake geometry engine were performed with a standard two-equation k-E turbulence model. The results revealed the presence o f secondary recirculating flows near the head-cylinder and piston-cylinder intersections which are very different in nature from those calculated for a laminar flow. A detailed analysis showed that these flow features are driven by the nonisotropic contributions to the normal components of the Reynolds stress tensor as predicted by the k-E model. Comparison calculations o f the one-dimensional compression of homogeneous turbulence using the k-E model, and a Reynolds stress model derived from direcl simulation of turbulence, indicate that the k-E predictions of the Reynolds stresses are satislaclory early in the compression stroke. However, near TDC. they become highly inaccurate. This finding pertains only to the central homogeneous region o f the flow and does not provide direct insight into the accuracy o f the k-E predi...