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Beach placer gold has been mined around the world historically, but extraction of fine (~ 100 µm) gold particles is notoriously difficult. This study illustrates morphological and mineralogical changes that transform fine gold during aeolian processes on windy beaches and contribute to mine concentration inefficiencies. Sandblasting on exposed beaches in southern New Zealand has caused extreme attenuation of edges of gold flakes that were previously transported in rivers for > 200 km. Flakes have been transformed into complex but compact toroids and spheroids with thin (~ 20 µm) internal and external strands of attenuated gold. Most of the gold within the attenuated strands has recrystallised to fine (micron-scale) undeformed grains with little or no Ag (< 1 wt%). Some coarse (> 40 µm) gold grains remain from the precursor fluvial particles, and these retain original Ag contents (1–10 wt%). These coarse grains show substantial internal crystallographic deformation and sub-grain formation, although some of these strain effects may have been inherited from fluvial transport. Co-existing detrital platinum minerals are much less malleable than gold during sandblasting and have only minor (10-µm scale) toroidal deformation on edges of fluvial flakes. The complex frameworks of the fine toroidal and spheroidal gold particles can include air, water, and clay, which lowers their average density and so they commonly float on water and are readily entrained with other heavy minerals. The fine particle size, compact shapes, and clay coatings also resist mercury amalgamation. [ABSTRACT FROM AUTHOR]

Two kinds of reticulocytes, and atypical erythroid cells, were found in the blood of apparently healthy ducks with Wright–Giemsa (W–G) stain. The reticulin of network-type examples (nRtc) is of a large complex (3-D) form. The punctate reticulocyte (pRtc) contains small pin-point cytoplasmic granulations; both cells are distinct from a polychromatic RBC (pRBC). Atypical erythroid cells with oval or irregular shapes reminiscent of primary or yolk-sac RBCs (ysRBC) accompanied the Rtc. Rare binuclear cells (bi) were either polychromatic (pRBC and pRtc) or full hemoglobin (Hb) types (RBC). Some bi with equal-sized daughter nuclei were presumed mitotic products. Conversely, unequal daughter nuclei were a mitotic products, a nuclear division without chromosomes or a spindle. Erythrocytes formed tight aggregations with thrombocytes or other cells called "toroids"; further indicating a reactive hemogram. Erythroplastids (ep) a nuclear erythroid cells, found along with other atypia, were either pRBC or full Hb types. The total white blood counts (TWBC) of the study set ranged from 5 K/μL (embryo E [d24]) to >100 K/μL (older ducks) with heterophil ratios (H/L) ranging from 0.5 to >4.0. Atypical erythroid cells, like atypical leukocytes, indicate a transition from homeostasis to a reactive state. Recognition of nRtc, pRtc, and toroids as reactive forms, expands the utility of hematologic data in assessing stress levels, indicating pathology, and exploring welfare questions. The present observations support earlier work showing some reticulocytes are detected by W–G alone and do not require vital dyes. Cells and behaviors described here demonstrate the benefit that a description of overall cytology adds to H/L ratios in evaluating a hemogram. [ABSTRACT FROM AUTHOR]

Substrate-embedded inductors enable the miniaturization of power modules and integrated voltage regulators (IVRs) with higher power efficiencies and performance. However, embedded inductors for single-stage 12- or 48–1-V high-conversion-ratio IVRs present new performance challenges due to limitations in magnetic materials, limited space, high frequency, and low duty cycle. In this work, we analyze seven embedded inductor designs fabricated with four metal-polymer composites magnetic materials. These inductors have inductances ranging from 20 to 500 nH, dc resistances between 14 and 40 mΩ, and saturation currents from 100 mA to over 5 A. Each inductor is characterized for its small-signal spectra with and without dc bias current and for its large-signal response. With all these measurements, a relation between the small- and large-signal losses is made, showing that using the new Racx metric, they are related by a factor κ. The measurements show that, in the megahertz range, the large-signal losses can be over four times larger than the small-signal ones. These analyses allow us to understand the material properties and modeling new magnetic materials targeted for high-conversion-ratio IVRs with input voltages greater than 5 V. [ABSTRACT FROM AUTHOR]

High-density package-embedded inductors enable the miniaturization of high conversion ratio integrated voltage regulators (IVRs). In this work, we present a new embedded inductor structure along with a new performance metric called effective ac resistance per unit inductance and how the inductor sets constraints to the power stage topology. The proposed performance metric depends on the converter duty cycle and frequency and uses the inductor current harmonics, its inductance and resistance spectra, and the large-signal response to compute the inductor losses. No information of the inductor volume or its magnetic field distribution is used. The proposed embedded inductor structure shows a toroidal field distribution using a combination of slots through a magnetic sheet and vias through these slots. The new structure enables the fabrication of several inductors in the same magnetic substrate for multiphase IVR. The proposed inductors are fabricated and the metric is demonstrated with measurements using a high saturation magnetic material, where an interesting relation between the small- and large-signal losses was observed. [ABSTRACT FROM AUTHOR]

Spatially tuning core permeability of an electromagnetic device enables superior performance. A permeability profile can be heuristically selected to improve the flux distribution in a device with a given geometry, but in order to fully leverage the capacity of spatial dependent permeability engineering, the geometry and the permeability should be optimized simultaneously. The work in this article herein presented sets forth a multiphysics design optimization paradigm that includes the permeability profile tuning in the context of both inductor and converter design. This approach enables the determination of Pareto optimal fronts consisting of a set of optimal solutions against competing objectives (e.g., mass and loss) under imposed constraints. To this end, computationally efficient analytical solutions of the heat transfer and electromagnetic formulations are derived for toroidal inductors, which are validated with finite-element analysis-based simulations. The software implemented in MATLAB 2018b is available online as an attachment to this article. [ABSTRACT FROM AUTHOR]

Many applications in communications and power electronics demand inductive components that operate at high frequency or a broad range of frequencies. For applications requiring miniature devices with large inductance values, most often the components are manufactured imprecisely in the traditional method where magnetic cores are wound with a fine gauge wire. To achieve the best high-frequency performance, there is a desire to use a practical manufacturing method that removes the imprecision of wire winding. In this article, a unique 3-D laser exposure system is used to direct-write conformal winding patterns on the surface of MnZn ferrite toroids. The toroidal helix windings were fabricated by both an additive laser direct structuring (LDS) process and a subtractive laser-written mask-and-etch process. Both methods were performed on both enamel-coated ferrites and bare ferrites. The performance and equivalent circuit model parameters of the transformers were measured up to 1.5 GHz and will be presented. The transformers fabricated on the enamel-coated cores were found to have comparable or better inductances and broadband coupling than wire-wound transformers of matching construction. [ABSTRACT FROM AUTHOR]

In this paper, we present two options of the toroid magnetic spectrometer dedicated to measure the energy and the polar and the azimuthal angles of the scattered from the ion's nuclear electrons in the future electron-ion collider DERICA at JINR. These options differ by the opposite sign of the magnetic field. In one of the options, the toroid magnetic field bends electrons towards the collision line, while in the option with the inverted field a bent is done outwards from the beam axis. We show that the last case provides much larger useful fraction of a solid angle for detection of the scattered electrons. The momentum resolution of such a spectrometer is estimated. [ABSTRACT FROM AUTHOR]

• A chemical trigger to a droplet floating on a fluid can self-organize a fluid-toroid. • Conditions for the formation of symmetric to asymmetric torus are identified. • The phenomenon is also associated with the formation of fluid-sheet, dewetting of the same to form droplets. • Roles of chemical triggers and droplet materials are also investigated. • A stability analysis predicts the cross-sections of the toroids and the spacing of droplets after its breakup. Mixing of a chemical trigger of lower surface tension into a microdroplet with relatively higher surface tension can cause a rapid spreading of the droplet on a liquid-sublayer to form a host of metastable liquid morphologies such as sheets, toroids, threads, or droplets. Subsequently, such metastable fluidic objects break into a collection of droplets to form microemulsions. Introduction of surfactant loaded water or long-chain alcohols into an oleic acid microdroplet stimulate a rapid spreading of the same on a water sublayer, which helps in the formation of a metastable liquid sheet connected to a liquid toroid. Much like slipping films, the liquid sheet dewets the water underlayer through the formation of holes before they grow and coalesce to form liquid ribbons. While such liquid structures eventually break into an array of microdroplets, the liquid toroid expands before undergoing a Plateau-Rayleigh instability to form microdroplets. A single step self-organization process in which a chemical trigger can convert a microdroplet into a liquid-toroid on a water surface, in absence of any rotational influence. A symmetric to asymmetric transition in toroid morphology is observed due to the changeover of laminar to turbulent flow regimes with the reduction in viscosity of fluid-sublayer or variation in chemical triggers. The toroid cross-section and droplet spacing after the toroid breakup follow a length scale evaluated from a linear stability analysis. [ABSTRACT FROM AUTHOR]

Actors in the Prisoner’s Dilemma agent-based model presented here decide between cooperation and defection in binary interactions determined by distance and overall gains. The paper thus tries to answer one of the fundamental questions of international politics: how does cooperative behavior perform in an environment governed by power and location? Two kinds of noise and the reward for mutual cooperation oscillating between temptation and punishment payoffs with a variable speed were added similarly like few completely new strategies inspired by foreign policy behavior of states. The initial success of generous reciprocal altruists is no surprise, but the lacking relationship between frequency of interactions and cooperativeness at the level of pairs already suggests some similarity with the system of states. Yet, the most important outcome is victory of the balance of threat strategy in all reruns with a heterogeneous pool of actors, despite the fact that this strategy was one of the least cooperative ones. At the same time, rules pre-selected by their success in the homogeneous and cooperative environment were still able to sustain intensive cooperation among themselves even within the heterogeneous pool of strategies. [ABSTRACT FROM AUTHOR]

Erythrocytes must maintain a biconcave discoid shape in order to efficiently deliver oxygen (O2) molecules and to recycle carbon dioxide (CO2) molecules. The erythrocyte is a small toroidal dielectrophoretic (DEP) electromagnetic field (EMF) driven cell that maintains its zeta potential ζ with a dielectric constant (ε) between a negatively charged plasma membrane surface and the positively charged adjacent Stern layer. Here, we propose that zeta potential is also driven by both ferroelectric influences (chloride ion) and ferromagnetic influences (serum iron driven). The Golden Ratio, a function of Phi u; offers a geometrical mathematical measure within the distinct and desired curvature of the red blood cell that is governed by this zeta potential and is required for the efficient recycling of CO2 in our bodies. The Bio-Field Array (BFA) shows potential to both drive/fuel the zeta potential and restore the Golden Ratio in human erythrocytes thereby leading to more efficient recycling of CO2. Live Blood Analyses and serum CO2 levels from twenty human subjects that participated in immersion therapy sessions with the BFA for 2 weeks (six sessions) were analyzed. Live Blood Analyses (LBA) and serum blood analyses performed before and after the BFA immersion therapy sessions in the BFA pilot study participants showed reversal of erythrocyte rheological alterations (per RBC metric; P = 0.00000075), a morphological return to the Golden Ratio and a significant decrease in serum CO2 (P = 0.017) in these participants. Immersion therapy sessions with the BFA show potential to modulate zeta potential, restore this newly defined Golden Ratio and reduce rheological alterations in human erythrocytes. [ABSTRACT FROM AUTHOR]

Considering recent application of concentration driven motion of charged nanoparticles in sensing technology, we model the diffusiophoresis of an isolated toroidal polyelectrolyte (PE) for the first time. Choosing an aqueous KCl solution for illustration, its behavior under various conditions is simulated by varying the double layer thickness, the size of toroid, and its softness and fixed charge density. We show that the behavior of the present PE can be different both quantitatively and qualitatively from that of the corresponding spherical PE. This arises from the competition of the hydrodynamic force and the electric force acting on a PE. The geometry and the nature of a PE can also influence appreciably its behavior, yielding complicated and interesting results. [ABSTRACT FROM AUTHOR]

In this paper, the design of an RF broadband transformer for wideband code division multiple access (WCDMA) tracking generators to be used in envelope tracking RF power amplifiers systems is presented. A ferrite toroidal core with a trifilar wound RF broadband transformer has been chosen to satisfy the (WCDMA) bandwidth requirement and also the power amplifier performance criteria that include the efficiency, electrical isolation, size and power consumption. The design components investigated comprises ferrite materials, number of turns on core windings and size. [ABSTRACT FROM AUTHOR]

This research attempts to find a new closed-form solution for axial flux permanent-magnet (AFPM) machines and applies it in a traction application example. The machine types considered are with toroid and overlapping windings. The proposed closed-form solution includes analytical derivations for winding lengths, resistances, and inductances as functions of fundamental air-gap flux density and inner-to-outer diameter ratio. Finite-element analysis is used to verify the accuracy of the proposed analytical calculations. Furthermore, a parametric analysis is performed on inductances, resistances, phase back-EMFs, phase terminal voltages, efficiencies, and torque speed capability to compare for both winding types. The proposed solution should assist traction machine designers to ascertain benefits and limitations of the toroid and overlapping winding types in traction application as well as to achieve faster design results. [ABSTRACT FROM AUTHOR]

Gold-bearing beaches at the western end of Foveaux Strait are being fed by the Waiau River, which is dominated by greywacke detritus. At times during the Pleistocene, debris from crystalline rocks in Fiordland has fed the Foveaux Strait beaches, and the greywacke detritus was diverted farther east. In contrast, the Round Hill placer goldfield has been dominated by locally derived fluvial felsic and mafic debris in the late Pleistocene to Recent. Gold particles in the Round Hill goldfield are toroidal in shape, and have been recycled from older beach sediments. Some gold toroids on active beaches may have been recycled from older beach sediments as well, whereas some may have formed in situ. Most gold toroids have encrustations of polymorphic clays and bio-organic matter, locally impregnated with fine-grained authigenic gold, and some toroids hosted in fluvial sediments display delicate authigenic gold overgrowths as a result of the biogeochemical transformation of gold. These biogeochemical processes appear to have little effect on co-existing detrital platinum group minerals such as isoferroplatinum. [ABSTRACT FROM AUTHOR]

The construction of the LHC detectors presented formidable challenges and, together with physics exploitation, has required the resources and talents of many thousands of scientists and engineers. [ABSTRACT FROM AUTHOR]

Filament wound isotensoidal structures are recently gaining more attention for designing composite pressure vessels. In this paper we present the governing equation for creating geodesic-isotensoids based on the netting theory and geodesic winding law. The feasible intervals of the isotensoid-based design are also determined. The isotensoid-based dome profiles are determined by solving the governing equation with geometrical and initial winding conditions. When the applied axial load reaches a certain magnitude, the isotensoidal toroids can be obtained by forcing the isotensoid-based dome profile to become closed. The comparisons of the cross-sectional shapes between the isotensoidal dome and the hemispherical dome, and between the isotensoidal toroid and the circular toroid, are performed to demonstrate the preferable performance of the isotensoids. It is concluded that the isotensoid-based design leads to uniform fiber tension throughout the whole shell and the resulting structure can thus be considered as optimal for a pressure vessel. In addition, the isotensoid-based profiles show lower aspect ratios than the conventional vessel profiles under the given volume and internal pressure. Therefore the structural performance and the conformability to limited-height storage space of pressure vessels can be improved using the isotensoid-based design. [ABSTRACT FROM AUTHOR]

The interactions of the naturally available botanicals with DNA molecules have received considerable attention owing to the potential to develop for medicinal agents. In this study, the interaction of proanthocyanidins with DNA molecules was studied by atomic force microscopy (AFM) and spectroscopic method. The AFM observation indicated that proanthocyanidins induced DNA molecules from double helix chains to the thick rope and toroids. The heights of the formed DNA structures are more than eight times than that of DNA double helix. Spectroscopic measurement results revealed that proanthocyanidins intercalated between the base pairs of DNA in the intercalative binding mode, which resulted in unwinding the DNA helix, twisting the DNA strands and finally transforming into the supercoiled DNA structures. All these results implied that DNA molecule is an important interaction target of proanthocyanidins, and the formed compact DNA structures have biological significance on the gene expression and regulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Toroidal gold forms by sandblasting on exposed beaches. • Pleistocene tectonic uplift raised beaches >50 m above present sea level. • Subaerial erosion concentrated toroidal gold in fluvial gravels. • Strong groundwater alteration occurred with varying redox conditions. • Groundwater alteration formed authigenic clay, pyrite, ferrihydrite, and gold. Pleistocene placer gold accumulation in coastal sediments during fluctuating Pleistocene sea levels and active tectonic uplift in southern New Zealand provides a well-constrained model for processes that have affected paleoplacers formed in similar settings in older rocks, going back to the Archean. Initial gold concentration occurred > 200 ky ago on exposed sandy beaches, where sand-blasting processes deformed fluvially-transported (~200 km) flakes into toroids, dumbells and spheroids. This gold was recycled into younger gravel-bearing sediments < 30 m thick during subsequent uplift (>50 m) with negligible morphological changes during < 10 km of fluvial transport. Most of the gold accumulated in basal fluvial gravels hosted in channels incised into gabbroic basement. Groundwater in the sedimentary sequence was derived from rain with marine aerosols and had the composition of dilute sea water. This low-temperature groundwater interaction has altered mafic clasts and immediately underlying basement to clays dominated by smectites and kaolinite, with some clay cementation. Groundwater alteration occurred under a wide range of redox and pH conditions that were lithologically controlled, principally by permeability contrasts at the centimetre to metre scale. Hence, oxidised waters produced clays impregnated with ferric iron oxyhydroxide, and reduced waters generated authigenic pyrite. Some of this pyrite was subsequently oxidised with localised acidification. Micron scale dissolution of gold via chloride, thiosulphate and bisulphide ligands led to authigenic gold impregnation of clays. Basal gravels contain clasts that have been pervasively clay-altered, partially clay-altered, and only incipiently clay-altered, attesting to repeated fluvial reworking to basement of the channelised sediments, and progressive gold concentration. [ABSTRACT FROM AUTHOR]

In this paper, self-assembled polymeric toroids formed by a temperature-driven process are reported. Rhodamine B (RhB) end-capped poly( N-isopropylacrylamide) (PNIPAAm) demonstrating a lower critical solution temperature (LCST) is prepared. In a two-phase system, the polymer in the aqueous phase could move to the chloroform phase on raising the temperature above its LCST. This temperature-driven process results in the formation of polymeric toroids in the chloroform phase, and the strategy affords a new pathway to toroidal self-assembly of polymers. Moreover, the photoluminescent behavior of the RhB end-capped PNIPAAm species formed by the process is also studied and discussed. [ABSTRACT FROM AUTHOR]

Morphologies of placer platinum group minerals (PGM) are more variable and resistant to modification during transport than placer gold grains. This study documents morphological evolution of PGM placer grains during up to 120 km of transport in beach placers after river transport from inferred sources up to 200 km inland. PGM morphological changes are calibrated with changes in morphology of associated placer gold. Most of the PGM are Pt-Fe alloy and have been fed into the beach placer system from a large river at the western end of the beaches on the south coast of New Zealand. The incoming fluvial PGM suite includes Os, Ir and Ru alloys which may have been derived from distal ophiolitic sources. More proximal sources have Ural-Alaskan affinities and these contributed cooperite and braggite, or sperrylite, locally, as well as Pt-Fe alloy grains. Some PGM may have been recycled through Cretaceous-Quaternary fluvial sediments before entering the modern placer system. Recycled placer PGM grains have also been derived from elevated Quaternary beaches near the coastline. PGM grains entering beach placers have rough surfaces, with remnants of crystal faces, and these evolve to smooth flakes with progressive long-shore transport. PGM flakes have slightly thickened rims caused by impacts by saltating sand on windy beaches, and the most distal beach placers contain flakes with incipient toroidal shapes. These PGM incipient toroids are poorly developed compared to accompanying well-formed toroidal gold that has developed in nearly all beach placers, including those on elevated Quaternary beaches. Typical PGM and gold placer grain size decreases with increasing distance of transport, from fluvial grain size of 400-1,000 to ∼200 microns on the most distal beaches, accompanied by eastward loss of equant PGM grains and associated increase in proportion of flakes. Although net transport distance is ∼120 km in the beach placer complex, frequent aeolian transport of grains from beach to dunes and subsequent recycling by storm surges substantially increased total transport distance in a dynamic windy tectonic environment. [ABSTRACT FROM AUTHOR]

High frequency toroidal model is developed and used to calculate several critical inductor parameters such as inductance, resonance frequency, quality factor, power loss, flux density with good accuracy for high power RF applications. The model that is developed is then transformed to the equivalent circuit, which is used by impedance analyzers to compare measurement and calculate results for several parameters. Full design and characterization program Matlab GUI has been generated to calculate and present high frequency characteristics of the toroidal inductor graphically. Program gives all the required design critical parameters, 15 output characteristic curves with high accuracy. The program can be used for commercial and academic applications. The accuracy of the program has been tested on several assembled inductors. The calculated results have been compared to the measured results and good agreement has been observed on all of them. [ABSTRACT FROM PUBLISHER]

Abstract: This paper presents a novel design approach combining isotensoidal structures with non-geodesic winding patterns, which is able to significantly improve the geometric flexibility and structural performance of composite toroidal hydrogen storage tanks. The fiber trajectories are allowed to deviate from geodesics and the slippage coefficient is introduced to enlarge the design opportunities of toroidal pressure vessels. With the aid of the netting theory and fiber slippage law, the governing equations for specifying the meridian profiles of non-geodesic-isotensoids are derived based on the condition of uniform fiber stress. The desired toroids are then obtained by forcing the non-geodesic isotensoidal meridian profiles to become closed. The resulting cross-sectional shapes and winding angle distributions are outlined, corresponding to various slippage coefficients of non-geodesics. The vessel performance factors are determined to demonstrate the better structural efficiency that the application of non-geodesics can achieve. The results show that the vessel performance improves by using non-geodesics, due to the overall decrease in winding angles of the fiber trajectories. It is also concluded that the structural performance of isotensoidal toroids can be further improved with increasing the slippage coefficient of the non-geodesic trajectories. [Copyright &y& Elsevier]

A SMES magnet can be operating in three different modes: charging, storing, and discharging. The eddy current losses and magnetization losses are generated during charging and discharging in the SMES system. The eddy current losses per cycle are generated mainly during discharging period because the discharging period is generally shorter that for charging. Magnetization losses per cycle are generated mainly during the charging. In this paper, we investigated a decrease in eddy current losses according to the shapes of conduction cooling plates. The cooling plate having small eddy current losses was designed by dividing and slitting. Also, the magnetization losses in the toroidal coil constructed with many pancake coils were analyzed using 3-D finite element method during the initial charging period and some discharging periods in an operating scenario for the 2.5 MJ SMES. [ABSTRACT FROM AUTHOR]

A non-inductive coil is an essential element of a resistive superconducting fault current limiter (FCL). A bifilar pancake type non-inductive coil, which is most common type, has two drawbacks; difficulty of paralleling tapes and a high risk of electrical breakdown at the terminal part. Although the bifilar type is simple as an element, large-scale FCL needs quite a number of series and parallel connections between elements. To make a non-inductive coil using conventional inductive elementary coils, we propose a novel structure of the coil. It looks like a toroid but entire inductance is near zero. This coil can overcome the drawbacks of conventional bifilar coil. In this paper, we confirm the new concept by numerical analyses. A few kinds of new models are compared, and then we concluded the proposed toroidal shape one is most suitable. This new structure coil can help implement of a hybrid FCL which is to generate the magnetic field at only fault. [ABSTRACT FROM AUTHOR]

Abstract: The electrophoresis of a non-conducting rigid toroid in an unbounded Newtonian electrolyte solution having an arbitrary orientation is modeled theoretically under the condition of low surface potential. In particular, the influence of the orientation angle, defined as the angle between the applied electric field and the center line of the toroid, on its electrophoretic behavior as the thickness of double layer varies is investigated. The results of numerical simulation reveal that both the thickness of double layer and the orientation angle can influence appreciably the mobility of the toroid. In general, for a fixed orientation, the mobility of the toroid increases with decreasing double layer thickness, and for a fixed double layer thickness, the scaled electrophoresis mobility increases with increasing orientation angle. If the double layer is infinitely thin, then the present result reduces to that predicted by Smoluchowski, that is, the scaled electrophoretic mobility of the toroid is unity, and is not influenced by its shape. On the other hand, if it is infinitely thick, then the present result follows the same trend as that predicted by Henry, that is, the electrophoretic mobility of the toroid depends highly on its form effect, and the thicker the double layer the smaller that mobility. If the thickness of double layer is comparable to the radius of a toroid, the variation in the orientation angle can lead to as much as 40% difference in the mobility. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we consider a class of toroids generated by a meridian in a shape of quadrangle in an arbitrary position to the axis of revolution. We give geometrical meaning of the non-rigidity condition based on the position of the diagonals of meridian. Special classes of quadrangular meridians (trapezium, parallelogram, deltoid,… ) are discussed. The number of flexible toroids is considered. A tool SurfBend is developed for the rigidity and visualization. [ABSTRACT FROM AUTHOR]

Abstract: One of the most important issues for the design of toroidal hydrogen storage vessels reflects on the determination of the most efficient meridional cross sections. In this paper we outline the cross-sectional shape determination for filament-wound toroidal pressure vessels based on the continuum theory and the optimality condition of equal shell strains. With the aid of the geodesic law and the equal-stains condition, the continuum-based optimal cross sections are determined while taking into account the shell thickness build-up along the meridional direction. As an additional option, the influence of the theoretically required axial load on the resulting meridian profile is also evaluated and the results show that the meridian curve returns to zero altitude at a certain magnitude of that axial load and thus forms a closed dome. The cross-sectional shapes and structural performance of classical pressure vessels, circular and continuum-based optimal toroidal pressure vessels are respectively determined and compared to each other. The results reveal that toroidal hydrogen storage vessels designed using the optimal cross sections provide better performance than the circular toroidal vessels and the classical vessels. [ABSTRACT FROM AUTHOR]

The toroidal magnet system of the ATLAS Detector at CERN consists of a Barrel Toroid (BT) and two End Cap Toroids (ECT-A and ECT-C). Each toroid is built up from eight racetrack coils wound with an aluminum stabilized NbTi conductor and indirectly cooled by forced flow liquid helium. The three toroids operate in series at 20.5 kA with a total stored energy of 1.5 GJ. In order to verify the reliability and effectiveness of the quench protection system, series of fast dump tests have been performed first of the single toroids and finally of the entire toroidal magnet system. In this paper a model to simulate the fast dump of the ATLAS toroids in single mode operation and in full system configuration is presented. The model is validated through comparison with measured data extracted from the ramp-and-quench runs. The calculated energy dissipation in the various coils is in very good agreement (within 1-2%) with the enthalpy changes estimated from the temperature measurements of the different parts of the cold masses. The results confirm the safe operation of such a gigantic and complicated magnet system which is now ready for continuous running of the ATLAS Detector. [ABSTRACT FROM AUTHOR]

Electromagnetic waves, solving the full set of Maxwell equations in vacuum, are numerically computed. These waves occupy a fixed bounded region of the three-dimensional space, topologically equivalent to a toroid. Thus, their fluid dynamics analogs are vortex rings. An analysis of the shape of the sections of the rings, depending on the angular speed of rotation and the major diameter, is carried out. Successively, spherical electromagnetic vortex rings of Hill's type are taken into consideration. For some interesting peculiar configurations, explicit numerical solutions are exhibited. [ABSTRACT FROM AUTHOR]

A 600 kJ HTS SMES system has been developed for power system stabilization as a national project in Korea. Successful operating tests of the 600 kJ were recently completed. In this paper, a 2.5 MJ class SMES with HTS magnets of single solenoid, multiple solenoid and modular toroid type were optimized using a recently developed multi-modal optimization technique named multi-grouped particle swarm optimization (MGPSO). The objective of the optimization was to minimize the total length of HTS superconductor wires satisfying some equality and inequality constraints. The stored energy and constraints were calculated using 3-D magnetic field analysis techniques and an automatic tetrahedral mesh generator. Optimized results were verified by 3D finite element method (FEM). [ABSTRACT FROM AUTHOR]

The system of superconducting toroids in the ATLAS experiment at CERN consists of three magnets. The Barrel Toroid was assembled and successfully tested in 2006. Next, two End-Cap Toroids have been tested on surface at 77 K and installed in the cavern, 100-m underground. The End Cap Toroids are based on Al stabilized Nb-Ti/Cu Rutherford cables, arranged in double pancake coils and conduction cooled at 4.6 K. The nominal current is 20.5 kA at 4.1 T peak field in the windings and the stored energy is 250 MJ per toroid. Prior to final testing of the entire ATLAS Toroidal system, each End Cap Toroid passed a commissioning test up to 21 kA to guarantee a reliable performance in the final assembly. In this paper the test results are described. It includes the stages of test preparation, isolation vacuum pumping and leak testing, cooling down, step-by-step charging to full current, training quenches and quench recovery. By fast discharges the quench detection and protection system was checked to demonstrate a safe energy distribution within the magnet after a quench or a triggered fast dump. [ABSTRACT FROM AUTHOR]

Abstract: A magnet system of three superconducting toroids and a solenoid with record overall system dimensions of 25m in length and 22m in diameter, generate the magnetic field for particle bending in, respectively, the muon and inner detectors in the ATLAS experiment at the Large Hadron Collider. The magnet technology is based on aluminum stabilized NbTi superconducting cables wound into impregnated windings which are conduction cooled and operate at 4.6K. Magnetic field is generated in the usable detector area of about 12000m3 and the peak field in the coil windings is 4.1T. The magnet system stored energy is 1.6GJ. After successful on-surface tests the magnets were installed in the ATLAS cavern 100m underground. The Barrel Toroid and Solenoid were charged to full field in autumn 2006 while both End Cap Toroids are powered in November 2007 thereby completing this very challenging and largest magnet system successfully constructed so far. [Copyright &y& Elsevier]

The ATLAS Experiment at LHC, CERN will utilize a large, superconducting, air-cored toroidal magnet system with a long Barrel Toroid and two End Cap Toroids. Each End Cap Toroid contains eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately 10 m diameter and 5 m length. The operating current is 20.5 kA at 0.25 GJ stored energy and a peak field of 4.1 T in the windings. This paper presents the status of the End Cap Toroid Project. Final integration of the two cold masses, 120 tons each, into their respective vacuum cryostats is described. The specialized techniques, procedures and tooling infrastructure required for these operations are explained. Pre-installation cooldown to 85 K is reported. Installation of the toroids in the ATLAS cavern 100m underground will be described. The final interfacing to the Barrel Toroid and services in the cavern will be reviewed along with preparations for final test and commissioning. [ABSTRACT FROM AUTHOR]

The ATLAS Detector at the Large Hadron Collider at CERN is equipped with a superconducting magnet system that consists of a Barrel Toroid, two End-Cap Toroids and a Central Solenoid. The four magnets generate the magnetic field for the muonand inner tracking detectors, respectively. After 10 years of construction in industry, integration and on-surface tests at CERN, the magnets are now in the underground cavern where they undergo the ultimate test before data taking in the detector can start during the course of next year. The system with outer dimensions of 25 m length and 22 m diameter is based on using conduction cooled aluminum stabilized NbTi conductors operating at 4.6 K and 20.5 kA maximum coil current with peak magnetic fields in the windings of 4.1 T and a system stored magnetic energy of 1.6 GJ. The Barrel Toroid and Central Solenoid were already successfully charged after installation to full current in autumn 2006. This year the system is completed with two End Cap Toroids. The ultimate test of all toroids by which maximum mechanical and thermal loads are exerted is being prepared and will be performed late 2007 where after normal operation will commence. The status of the project in its nearly completed state as well as the first experience with testing and operation in the underground cavern are reported. [ABSTRACT FROM AUTHOR]

The ATLAS particle detector presently being installed at the LHC at CERN requires magnetic field for charged particles bending in an 8000 m³ volume. A system of four superconducting magnets was designed comprising a Central Solenoid making 2 T for the inner detector as well as two End-cap Toroids and a Barrel Toroid generating the about one tesla magnetic field for the muon detectors. The magnet system with a stored energy of 1.6 GJ is sized 22 m in diameter and 26 m in length. After about 15 years of design, construction in industry, system integration at CERN and installation in the underground cavern, the completion is imminent. At present, in August 2006, the Central Solenoid is operational, the Barrel Toroid installation complete and 4 K tests in progress and the 2 End Cap Toroids are being integrated and will soon be installed as well. Magnet services for vacuum, He cryogenics, power converters and circuits as well as controls and safety systems are operational. In the paper the status of the various magnets is reviewed and the first experience and test results with the magnets installed are reported. [ABSTRACT FROM AUTHOR]

Abstract: The genomic DNA in cells of Escherichia coli is localized in one or two compact, phase-like regions with characteristic shapes. Nucleoids undergo progressive changes in shape and compaction in the presence of drugs such as chloramphenicol or puromycin. Forces which influence nucleoid shape and compaction are reviewed, with particular emphasis on crowding effects of the cytoplasm and confinement effects of the cell envelope. Based in part on the theory of Kornyshev and Leikin for interaction between DNA duplexes, the folding of DNA caused by binding of DNA-associated proteins is suggested to antagonize DNA condensation and, thereby, increase access to DNA sequences. These views are incorporated into a working model for nucleoid organization. [Copyright &y& Elsevier]

The ATLAS detector for the LHC collider at CERN requires a large superconducting Barrel Toroid (BT) with overall dimensions of 25 m length, 22 m diameter which is installed in the ATLAS cavern 100m underground. The Barrel Toroid provides the magnetic field for the muon detector. The toroid is assembled from 8 flat race track coils of dimensions 25m × 5m. Following the on-surface acceptance test of the 8 BT coils, they are successively inserted in the underground cavern and assembled as a full toroid by using 16 supporting rings of struts that link the 8 coils to form a rigid and stable structure. The total mass of the toroid is 850 t. Particular issues are that the axis of the toroid has to be horizontal and the final shape of the toroid cylindrical with a tolerance of +/-10 mm with respect to an overall system diameter of 22 m. The desired shape of the toroid can only be controlled by installing the 8 coils in calculated positions in space (forming an elliptic shaped structure), and by linking them using bolted struts linking the coils. The final release of the structure is done under its self weight hydraulically. This required very large tooling essentially to support all the 8 coils in space in a nearly stress free condition until the toroid supporting rings have been closed. The theoretical positions are found by performing detailed 3-D Finite Element Calculations that predict the shape of the toroid under its operational load. The assembly of this huge toroid is unique and no experience basis exists. This paper presents the concept and technology required for the assembly of the toroid as well as the cryogenic supply lines, highlights the FEA mechanical calculations performed to predict the shape, summarizes the tooling required and reviews the experience gained during the installation. [ABSTRACT FROM AUTHOR]

The ATLAS experiment at LHC (CERN) will utilize a large, superconducting, air-cored toroid magnet system with a long Barrel Toroid and two End Cap Toroids. Each End Cap Toroid will contain eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately 10 m diameter. This paper presents the design principles and realization of the cold mass assembly. The procedures for integration of the full cold mass, 120 tonnes, into the vacuum cryostat are described. The overall status of toroid magnet integration and planning for test and installation is reviewed. [ABSTRACT FROM AUTHOR]

The Barrel Toroid (BT) provides the magnetic field for the muon detectors in the ATLAS experiment at CERN. The Toroid is built up from eight superconducting coils. Each coil consists of two 25 m × 5 m racetrack shape double pancakes impregnated and pre-stressed inside an aluminum coil casing. The 42-tons cold mass is cooled by forced-flow liquid helium circulating in aluminum pipes glued to its surface. The coils are tested on surface prior to their underground installation. The test program has started in September 2004 and finished in June 2005. This paper describes the test set up and various commissioning tests performed at the ATLAS Magnet Test Facility. It includes the aspects of test preparation, vacuum pumping, leak testing, cooling down, powering and warming up. The 8 coils have passed the tests successfully and have been assembled into the Toroid in the ATLAS cavern. The testing completes the production of the so far largest racetrack coils in the world. [ABSTRACT FROM AUTHOR]

The Superconducting Barrel Toroid is providing (together with the two End-Cap Toroids not presented here) the magnetic field for the muon detectors in the ATLAS Experiment at the LHC at CERN. The toroid with outer dimensions of 25 m length and 20 m diameter, is built up from 8 identical racetrack coils. The coils with 120 turns each are wound with an aluminum stabilized NbTi conductor and operate at 20.5 kA at 3.9 T local field in the windings and is conduction cooled at 4.8 K by circulating forced flow helium in cooling tubes attached to the cold mass. The 8 coils of 25 m × 8 m are presently under construction and the first coils have already been fully integrated and tested. Meanwhile the assembly of the toroid 100 m underground in the ATLAS cavern at CERN has started. The 8 coils are individually tested on surface before installation. In this paper the test of the first coil, unique in size and manufacturing technology, is described in detail and the results are compared to the previous experience with the 9 m long B0 model coil. [ABSTRACT FROM AUTHOR]

Abstract: In the mid 1960s the present authors published two papers dealing with penetration of nonwetting liquids such as mercury into the interstitial void spaces using the model of uniform packed spheres. A circular arc was used to approximate the liquid–vapor interface in both papers. However, our circular arc–toroid values for the pressure–volume relationship in the pendular ring which exists between two touching spheres was criticized. The authors concluded that our approximation led to unacceptably large differences compared to the values calculated from the exact nodoid shape. This incorrect conclusion was never rebutted and has, in fact, been misinterpreted by subsequent workers to include values calculated for the shape of the access opening and the associated pressure for penetration into the void space of a collection of spheres. This leaves a cloud of uncertainty, not only over our original work on nonwetting fluids, but on the application of our procedures to the field of wetting fluids. The contrast in the geometrical shapes of the toroid and nodoid is depicted and the pressure values are compared at equal volumes. In contrast to the claim of excessive error, we show the toroid geometry, in conjunction with a pressure–volume work derivation, to have a maximum error of 0.06% as compared to the nodoid at all liquid–solid contact angles. The toroid also has the advantage of using a readily derived work versus surface free energy balance rather than requiring the use of incomplete elliptic integrals to evaluate the nodoid. Attempts to use radii of curvature to evaluate the toroid shape are shown to give extremely poor approximations of the exact values for the pressure. Values reported for access to the interior void space of a collection of spheres still need adjustment for the effect of contact angles between 0° and 180° for characterizing assemblies of real solids by computing “equivalent spherical” particle size from porosity and mercury penetration data. However, there is no anticipation that use of the circular arc will introduce large errors in the results. This gives confidence to us and others working with wetting media to test the potential applicability of the packed sphere model to various diverse fields. [Copyright &y& Elsevier]

Inclusion problems for elongated toroidal inclusions are solved to discuss the strain fields caused by eigenstrained doughnut-like and tubular inclusions. For an infinitely long tubular inclusion, uniform eigenstrains do not generate elastic strains in the matrix region inside the tube. Effects of tube length on the elastic strains are shown for the purely dilatational eigenstrain #x03B5;*. For the tubular inclusion with the length 2b, the elastic strain at the center of the matrix region inside the tube becomes the maximum as much as ≈(a/b)#x03B5;* when the tubular inclusion has the inner diameter ≈2(b-a) and the outer diameter ≈2(b+a). [Copyright &y& Elsevier]

The ATLAS experiment at LHC, CERN will utilize a large, superconducting, air-cored toroid magnet system, with a long barrel and two end cap toroids. Each end cap toroid will contain eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately 10 m diameter. This paper presents the engineering design of the cryostat: vacuum vessel, thermal radiation shields and superinsulation. The manufacture of the major components is described with reference to the key factors for operation. The delivery to CERN and integration of the main components to form the cryostat assembly is described. [ABSTRACT FROM AUTHOR]

The superconducting Magnet System for the ATLAS detector at the LHC at CERN comprises a Barrel Toroid, two End Cap Toroids and a Central Solenoid with overall dimensions of 20 m diameter by 26 m length and a stored energy of 1.6 G.J. Common proximity cryogenic and electrical systems for the toroids are implemented. The Cryogenic System provides the cooling power for the 3 toroid magnets considered as a single cold mass (600 tons) and for the CS. The 21 kA toroid and the 8 kA solenoid electrical circuits comprise both a switch-mode power supply, two circuit breakers, water cooled bus bars, He cooled current leads and the diode-resistor ramp-down unit. The Vacuum System consists of a group of primary rotary pumps and sets of high vacuum diffusion pumps connected to each individual cryostat. The Magnet Safety System guarantees the magnet protection and human safety through slow and fast dump treatment. The Magnet Control System ensures control, regulation and monitoring of the operation of the magnets. The updated design, layout, development and construction of the systems, as well as the first results of prototyping and commissioning are presented. [ABSTRACT FROM AUTHOR]

The End Cap Toroid Magnets for the ATLAS experiment at LHC, CERN will Contain eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately Him diameter. This paper presents the engineering design of the cold mass and gives the status of the industrial production. The cold mass mechanical structure consisting of 8 coils and keystone boxes is described. Coil fabrication from component assembly, coil winding to final impregnation will be reviewed. The design and industrial manufacture of the keystone box elements is given. The cold mass assembly methods and status are described. [ABSTRACT FROM AUTHOR]

Human behaviours and consumer products may affect vaginal microbial ecology, thereby influencing women''s health. Relevant experimentation systems are needed to understand such possible links. Here, we describe the development of a practical semi-solid in vitro model to assess the effects of interactions between vaginal environment and the presence of tampons, on bacterial communities, including the production of toxic shock syndrome toxin-1 (TSST-1) by Staphylococcus aureus. [Copyright &y& Elsevier]

The strain field caused by uniform and purely dilatational eigenstrains is discussed for a doughnut-like inclusion. Near the doughnut-like inclusion, there are two points where all components of the strains are null. [Copyright &y& Elsevier]

The interaction of DNA with Tris(1,10-phenanthroline) cobalt(III) was studied by means of atomic force microscopy. Changes in the morphologies of DNA complex in the presence of ethanol may well indicate the crucial role of electrostatic force in causing DNA condensation. With the increase of the concentration of ethanol, electrostatic interaction is enhanced corresponding to a lower dielectric constant. Counterions condense along the sugar phosphate backbone of DNA when &epsiv; is lowered and the phosphate charge density can thus be neutralized to the level of DNA condensation. Electroanalytical measurement of DNA condensed with Co(phen)33+ in ethanol solution indicated that intercalating reaction remains existing. According to both the microscopic and spectroscopic results, it can be found that no secondary structure transition occurs upon DNA condensing. B–A conformation transition takes place at more than 60% ethanol solution. [Copyright &y& Elsevier]

The DNA of growing cells of Escherichia coli occurs in one or a few lobular bodies known as nucleoids. Upon exposure to chloramphenicol, the nucleoids assume compact, rounded forms (“cm-nucleoids”) that have been described as ring- or sphere-shaped. Multiple views of single cells or spheroplasts, however, support a different, curved toroid shape for cm-nucleoids. The multiple views were obtained either by DNA fluorescence imaging as the cells or spheroplasts reoriented in liquid medium or by optical sectioning using phase-contrast or fluorescence imaging of immobilized cells. The curved toroid shape is consistent with electron microscope images of thin sections of chloramphenicol-treated cells. The relationship of this structure to active and inactive nucleoids and to the smaller toroidal forms made by in vitro DNA condensation is discussed. [Copyright &y& Elsevier]