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Stokes' flows of an isochoric, Newtonian fluid in cylindrical geometries are analytically investigated. Transient and time asymptotic solutions are deduced and their main features as well as applications to engineering problems are discussed. In the classical problems a circular cylinder translates along its symmetry axis or rotates around it, the axial or azimuthal wall speed behaving in time as a finite step or periodically. The resulting velocities in the fluid filling the outside or the inside of the cylinder and the wall stresses involve Macdonald's functions (external flows) or modified Bessel functions of the first kind (internal) of order 0 or 1. Extended azimuthal and axial Stokes' problems are also introduced and solved. In the azimuthal problems, the cylindrical wall is cut in two parts by a plane normal to the axis: one part rotates, while the other one is kept at rest. The behavior of the azimuthal velocities and of the stresses in a neighborhood of the above plane is discussed. In the axial problems a strip (or also a finite number of strips) of the cylindrical wall translates, while its remaining part is kept at rest. Velocities and wall stresses are obtained by means of azimuthal Fourier series involving Macdonald's or modified Bessel functions of any integral order.

Recently, a few numerical methods based on the photoacoustic (PA) signal temporal shape analysis and energy density spatial distribution calculation, which is directly related to the laser beam spatial profile, have been presented. It has been shown that these methods allow a precise reproduction of the spatial profile and the radius of the laser beam, determining the vibrational-to-translational (V–T) relaxation time with good accuracy. Their applicability has been shown and confirmed for the analysis of an arbitrary symmetric laser beam spatial profile in cylindrical geometry. Here, the application of genetic optimization for solving the problem of a simultaneous laser beam spatial profile and V–T relaxation time determination by pulsed PAs is presented. Real-coded genetic algorithms are used to calculate the mentioned relaxation time by fitting the experimental signal $${\delta }{p}(\mathbf{\textit{r} }, t)$$ with the theoretical one. The aim is to find combinations of PA signal parameters, namely, the radius of the laser beam and the V–T relaxation time that provide the best match with the given signal. A calculated PA signal with a known profile is used to simulate an experimental signal, and the sum of the square deviations representing deviations of the given and fitted signals is minimized by means of genetic optimization. In that way, the genetic algorithms are used to simultaneously estimate the radius of the laser beam and the V–T relaxation time efficiently and with high accuracy. Compared to previous methods, the presented method is much simpler and requires less time to compute.

This paper presents a detailed simulation analysis of the erase performance of junction-less charge-trap memory arrays in the cylindrical geometry, showing that a saturation of the erased threshold voltage occurs as a result of incomplete inversion of the intercell regions when positive charge is stored in the cells. This erase saturation issue is investigated as a function of string and cell parameters, revealing lower erase capabilities for large cell-to-cell separation, small substrate radius, and small equivalent-oxide thickness of the gate stack. These results add new constraints to the design of cylindrical junction-less memory technologies.

We quantify nanocomposite toughness through a reanalysis for nanotubes of the Cottrell–Kelly–Tyson (CKT) model, of the definition of critical length, and of the energy dissipation model for pull-out. The effect of the hollow cylindrical geometry of nanotubes is discussed, followed by an examination of proper ways to compare energy dissipation at the nano and micro levels.

A model is described for use in translating measured heat flux to predict second and third degree hand burn injury in fire exposures. The model adapts a burn translation algorithm for estimating burn injuries used in established instrumented fire test manikin technologies. It facilitates more accurate prediction of burns to human hands by accounting for the cylindrical geometry of the fingers, bone tissue beneath the skin, and different skin thickness data that represents the different areas of the hand. A numerical modeling approach is used to demonstrate the response of the skin burn model for predicting hand burn injury in heat exposures encountered in fire manikin testing.

One of the latest generation developments regarding EAF taphole technology is the CFD-optimised EBT taphole, which is currently replacing common cylindrical tapholes all over the world. This paper compares the standard taphole (cylindrical geometry) with the new, flow-optimised solution. Influence on tapping time, taphole lifetime, and metallurgical benefits are explained. Additionally well proved systems to ensure a quick and safe taphole removal and exchange are discussed.

The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates., The European Research Council and the EU-H2020 program are gratefully acknowledged for co-funding this work through the projects Tonality (ERC-2014-PoC) and Marie Skłodowska-Curie Fellow (706094–TONSOPS). We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

International audience; Liquid foams are excellent systems to mitigate pressure waves such as acoustic or blast waves. Theunderstanding of the underlying dissipation mechanisms however still remains an active matter ofdebate. In this paper, we investigate the attenuation of a weak blast wave by a liquid foam. The wave isproduced with a shock tube and impacts a foam, with a cylindrical geometry. We measure the waveattenuation and velocity in the foam as a function of bubble size, liquid fraction, and the nature of thegas. We show that the attenuation depends on the nature of the gas and we experimentally evidence amaximum of dissipation for a given bubble size. All features are qualitatively captured by a model basedon thermal dissipation in the gas.

We simulate shock-free and shocked viscous accretion flow onto a black hole in a two dimensional cylindrical geometry, where initial conditions were chosen from analytical solutions. The simulation code used the Lagrangian Total Variation Diminishing (LTVD) and remap routine, which enabled us to attain high accuracy in capturing shocks and to handle the angular momentum distribution correctly. Inviscid shock-free accretion disk solution produced a thick disk structure, while the viscous shock-free solution attained a Bondi-like structure, but in either case, no jet activity nor any QPO-like activity developed. The steady state shocked solution in the inviscid, as well as, in the viscous regime, matched theoretical predictions well. However, increasing viscosity renders the accretion shock unstable. Large amplitude shock oscillation is accompanied by intermittent, transient inner multiple shocks. Such oscillation of the inner part of disk is interpreted as the source of QPO in hard X-rays observed in micro-quasars. Strong shock oscillation induces strong episodic jet emission. The jets also showed existence of shocks, which are produced as one shell hits the preceding one. The periodicity of jets and shock oscillation were similar. The jets for higher viscosity parameter are evidently stronger and faster., 24pages, 18figures. Accepted for publication in the Astrophysical Journal

In this paper, we study the dynamics of tilted cylindrical model with imperfect matter distribution. We formulate the field equations and develop relations between tilted and non-tilted variables. We evaluate kinematical as well as dynamical quantities and discuss the inhomogeneity factor. We also obtain the Raychaudhuri equation to study evolution of expansion scalar. The solutions of field equations are also investigated for static cylinder under isotropy and conformally flat condition. Finally, we analyze some thermoinertial aspects of the system.

We propose a spectral Particle-In-Cell (PIC) algorithm that is based on the combination of a Hankel transform and a Fourier transform. For physical problems that have close-to-cylindrical symmetry, this algorithm can be much faster than full 3D PIC algorithms. In addition, unlike standard finite-difference PIC codes, the proposed algorithm is free of numerical dispersion. This algorithm is benchmarked in several situations that are of interest for laser-plasma interactions. These benchmarks show that it avoids a number of numerical artifacts, that would otherwise affect the physics in a standard PIC algorithm - including the zero-order numerical Cherenkov effect., Comment: 23 pages, 8 figures

The aim here is to model the standing torsional oscillations in solar spicules in the presence of density stratification, magnetic field expansion, and steady flows. By implementing cylindrical geometry, the eigenfrequencies, eigenfunctions, and the period ratio P_1/P_2 of these waves is obtained for finite plasma-beta. The shifts created by the steady flow justifies the divergence of the observed period ratio for the first and second periods from the number 2.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2019-08-12T13:46:26Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_luana_lazzari.pdf: 971473 bytes, checksum: f706d3c825cf5e668557ff2da1341c2f (MD5) Made available in DSpace on 2019-08-15T11:47:20Z (GMT). No. of bitstreams: 2 dissertacao_luana_lazzari.pdf: 971473 bytes, checksum: f706d3c825cf5e668557ff2da1341c2f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-16 Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS No presente trabalho determina-se a solução analítica para a equação de trans- porte de nêutrons bidimensional em geometria cartesiana por meio do método de decomposição angular. Este método consiste em derivar a equação um número suficiente de vezes com relação a variável angular até obter uma equação diferencial. Após,resolve-se esta equação e sua solução é substituída no problema original. Assim, a solução obtida para a equação de transporte é composta por uma combi- nação linear de auto funções singulares,associadas a um conjunto de autovalores, análogas aos determinados por Case para o problema em geometria cartesiana unidimensional. Além disso,apresenta-se a solução analítica para a equação de transporte de nêutrons bidimensional em geometria cilíndrica para os casos com espalhamento isotrópico e espalhamento linearmente anisotrópico.Resolve-se o pro- blema isotrópico tomando como ponto de partida a solução da equação em geometria cartesiana,após fazer algumas mudanças de coordenadas.Novamente,encontra-se a mesma solução obtida por Case para os problemas em geometria cartesiana. Para o caso com anisotropia linear a solução é determinada a partir do resultado do problema em geometria cilíndrica com espalhamento isotrópico. Por fim,propõem-se adicionar os termos de anisotropia linear e quadrática à equação desenvolvida por Mitsis para um cilindro infinito com simetria azimutal e espalhamento isotrópico considerando os termos de fonte externa isotrópica e fluxo incidente constante no contorno. Para a construção destes termos de espalhamento considera-se que a solução destes problemas são compostas pelos mesmos autovalores determinados por Case para o problema em geometria cartesiana unidimensional com mesmo grau de anisotropia.Soluciona-se estas equações por meio do método HTSN, o qual consiste na aplicação do método SN para a discretização da variável angular juntamente com a transformada de Hankel de ordem zero e compara-se as soluções de cada equação com problema em geometria cartesiana com o mesmo grau de anisotropia. In the present work is determined the analytical solution to the neutron transport equation in two-dimensional slab geometry by angular de composition method. This method consists in deriveth e equations everal times with respect to angular variable forget a differential equation. After this equation is solved and its solution is replaced in original equation.Thus,the solution obtained to the neutron transport equation is composed by a linear combination of singular eigen functions associated the a setof eigen values analogous to determined by Case to the one-dimensional slab geometry problem.More over is presented the analytical solution to the neutrons transporte qua- tion in two-dimensional cylindrical geometry in the cases withs cattering iso tropicand linear an isotropic scattering.The isotropic problemis solved taking as starting point the solution the equation in slabge o metry afte rmaki heprobleminone-dimensional slab geometry.Forthecasewithlinearanisotropythesolutionisdeterminedfromthe problemincylindricalgeometrywithscatteringisotropic.Lastlyisproposedtoadd the linearandquadraticanisotropytermstotheequationdevelopedbyMitsisforan infinitely longcylinderwithazimuthalsymmetryandisotropicscatteringconsidering the isotropicinternalsourceandincidentneutronfluxfortheboundary.Forthecon- structionofthistermsisconsideredthatthesolutionofthisproblemiscomposedby same eigenvaluesdeterminedbyCasetotheone-dimensionalslabgeometryprob- lem withequivalentdegreeofanisotropy.Thisequationsaresolvedby HTSN method which consistsintoapplythe SN method tothediscretizationoftheangularvariable together withthezeroorderHankeltransformation.Thesolutionfoundarecompared with probleminslabgeometrywithsamedegreeofanisotropy.

N2F is a C/C++ code used to calculate the far zone electromagnetic (EM) field, given E and H near zone field data. The method used by N2F can be found in Ref. 1 and 2. N2F determines the far field EΦ and Eθ in spherical coordinates for near zone data calculated in either Cartesian or Cylindrical geometry.

International audience; The flash method, known as the most used experimental technique to measure the thermal diffusivity of solids, has been adapted to cylindrical highly diffusive and heterogeneous multilayered samples. In order to overcome the heterogeneities issue and give a more accurate estimation of the sample thermal properties, the front face and rear face thermal responses have been simultaneously recorded using an infrared camera. A homogeneous monolithic SiC cylinder has been tested to validate this experimental method which has finally been applied to 2D bi-layered SiC$_f$/SiC cylinders used for nuclear fuel cladding.

Various delivery applications have proved the efficient utilization of nanocontainers to overcome problems of volatility, hydrophobicity, sustainability, and slow/triggered release of active molecules. In the recent past there has been substantial study on the innovative methodology of fabricating nanovehicles of drugs, flavors, and aromas for various delivery applications. The main objective of these studies was to maintain the longevity of active moles of fragrance and aroma. The present study reports some of the recent developments in biocompatibility, slow and sustained release applications of drug, flavors, and aromas. The nanocontainers protect the cargo from external influence/environment and release it only in response to certain environmental conditions at the desired destination. One of our recent studies, briefly reported herein, highlights an inorganic nanocontainer substrate for successful encapsulation of fragrance molecules followed by responsive behavior of these nanocontainers for release of cargo in various pH mediums. Characterization studies of nanocontainers revealed the cylindrical geometry of nanocontainers with 800 ± 300 nm length, 30–50 nm outer diameters with approximately 15 nm hollow lumen. The responsive behavior was obtained by applying a thin layer of polyelectrolyte onto the nanocontainer surface. Here we present the release rate of fragrance in mgL–1 per g of nanocontainer per min. The release indicated that the fragrance release was responsive and the fragrance release increased with increase in pH value from 3 to 7. The chapter outlines the different types of nanocontainer, the mechanism of response and the different active molecules such as drugs, flavors, and aromas for delivery purposes. The potential directions further developments of sustainable biocompatible nanocontainers are also broadly covered herein.

Recycling of disused sealed radioactive sources (DSRS) is one of the milestones of radioactive waste management strategy that prompts the minimisation of the radiological hazard to human health and the environment. In this respect this study spotlights recovering and purification of 137Cs as a solution (with a radioactivity of 191.5 ± 3.9 MBq) from an old disused source. The method was designed to fulfil the regulations and legislations of radiation protection giving exposure doses of the operating staff within the international permissible limits. Separation of the chemical impurities was performed by hydroxide precipitation based on pH values and solubility constants. X-ray fluorescence analysis illustrated a removal efficiency of 99% for iron and chromium, whereas the concentration of nickel and manganese decreased to 80 and 7 mg L-1, respectively, in the purified 137Cs solution. The radiochemical recovery of the purification process was determined using gamma-spectroscopy and found to be 94.4%. The purified 137Cs solution was then used to prepare a gel-source with 20 mL cylindrical geometry. Calibration was carried out at a secondary standard laboratory “National Radioactive Measurement Laboratory” (NRML) that is traceable to the primary standard “National Physics Laboratory” in the UK (NPL), giving an activity of 10.59 MBq with relative uncertainty of 0.4-0.5%. The preparation procedure could be considered as an original, facile, feasible and cost effective method that implies beneficial reuse of a DSRS in terms of volume minimization of radioactive wastes.

We present an analytical treatment of diffusional release of a dispersed solute from a cylindrical non-erodible polymeric matrix and study the mechanism of diffusional release of solute from the matrix system as a function of solute loading parameter. The diffusion equation is solved exactly under perfect sink condition for certain concentration of solute in the form of cylindrical geometry. The numerical solution of diffusional release function as a function of time is found to be increased initially and then remain constant after certain time, tau(c). This tac(c) is found to be as a function of solute loading parameter. The asymptotic solutions of the diffusional release function is also presented.

This article presents results of solid–liquid phase change, the Stefan Problem, where melting is driven internal heat generation, in a cylindrical geometry. The comparison between a quasi-static analytical solution for Stefan numbers less than one and numerical solutions shows good agreement. The computational results of phase change with internal heat generation show how convection cells form in the liquid region. A scale analysis of the same problem shows four distinct regions of the melting process.

Cylindrical Korteweg-de Vries-Burgers (cKdVB) equation for magnetoacoustic wave is derived for dissipative magneto plasmas. Two fluid collisionless electromagnetic model is considered and reductive perturbation method is employed to study the propagation of magnetoacoustic shock waves in cylindrical geometry. Two level finite difference method is employed by using Runge-Kutta method to solve cKdVB equation numerically. The effects of nonplanar geometry, plasma density, magnetic field strength, temperature dependence and kinematic viscosity on magnetoacoustic shocks are investigated. The numerical results are also presented for illustration.

The actual distribution of charges on a metal does not guarantee its surface to be equipotential because of the impurities and microcrystal structure of the material. This phenomenon, known as patch effect, is responsible for the mutual force and torque between two metallic surfaces at a finite distance. Patch effect is important for any precision measurement whose set-up includes conducting surfaces in a closed proximity to each other. This is particularly true for the Satellite Test of the Equivalence Principle experiment where the differential motion of cylindrical test masses will be used to test the universality of free fall to an unprecedented accuracy of about 1 part in 1018.

The time-of-flight (TOF) small-angle neutron scattering (SANS) di_ractometer is one of the first instruments to be built at the Compact Pulsed Hadron Source (CPHS) of Tsinghua University. It requires a 1 × 1 m2 area detector to cover the designed Q-range without moving the detector. We contemplate an array of 1D linear position-sensitive detectors (LPSDs) of 3He gas proportional counters. Each LPSD will have a cylindrical geometry with an active length of 1 m and a diameter of 12 mm. We describe the in-house fabrication of the first LPSDs and the preliminary testing of their performance.

In this study, the steady and transient neutronic behaviour of MYRRHA ADS is investigated. For this purpose, a recently proposed analytical benchmark of the diffusion kinetics as 1D slab model of the MYRRHA ADS concept developed in Belgium has been extended to the cylindrical geometry which represents the system more realistically. Analytical calculations are performed using the Customized Solution Method and numerical Laplace inversion techniques such as Fixed-Talbot and Gaver-Wynn-Rho algorithms. Results are compared with the finite element program FLEXPDE® and they are found to be in complete agreement. The necessity of modeling the MYRHHA reactor in cylindrical geometry rather than slab geometry to obtain more realistic benchmark results is demonstrated.

Sheets to be thermoformed are often heated unevenly, with a higher temperature above the sheet. This results in upward bowing of the sheet, and this is caused by thermal expansion. We combine the analytical solution for the temperature gradient in a slab heated by radiation with a relationship developed from the cylindrical geometry of the sheet as it bows. We thus derive a dimensionless equation for sheet bowing as an implicit function of time for both top and dual heating. We thus uncover a new dimensionless group which we call sheet bowability. We find good agreement between our theory and our new top-heated sheet bowing measurements. We provide a worked example so that the engineer can see how to apply our results. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

The two-dimensional Ising model in the geometry of a long stripe can be regarded as a model system for the study of nanopores. As a quasi-one-dimensional system, it also exhibits a rather interesting “phase behavior”: At low temperatures the stripe is either filled with “liquid” or “gas” and “densities” are similar to those in the bulk. When we approach a “pseudo-critical point” (below the critical point of the bulk) at which the correlation length becomes comparable to the length of the stripe, several interfaces emerge and the systems contains multiple “liquid” and “gas” domains. The transition depends on the size of the stripe and occurs at lower temperatures for larger stripes. Our results are corroborated by simulations of the three-dimensional Asakura–Oosawa model in cylindrical geometry, which displays qualitatively similar behavior. Thus our simulations explain the physical basis for the occurrence of “hysteresis critical points” in corresponding experiments.

The paper investigates buckle propagation in deep sub-sea pipelines. Experimental results are presented using ring squash tests and hyperbaric chamber tests, and are compared with a modified analytical solution and with numerical results using finite element analysis. The experimental investigation was conducted using commercial aluminium pipes with diameter-to-thickness (D/t) ratio in the range 20-48. In contrast to conventional cylindrical pipe, a faceted cylindrical geometry is also investigated. Preliminary analysis of a faceted pipe shows that a substantial increase in buckling capacity can be achieved for the same D/t ratio.

Spontaneous formation of a chiral structure of a polymer-stabilised achiral nematic liquid crystal with cylindrical geometry was suggested. A structurally achiral planar-radial configuration was converted to a coherently swirling twisted-escaped configuration with long time constant of about 10 h. This deformation is considered to be an energy minimising process and an asymmetrically covered polymer layer on the substrate surface seems to be responsible for the escaping process. By reducing the ultraviolet intensity, both substrates were symmetrically covered with the polymer layers and, consequently, a topologically different bipolar configuration was induced.

Gridded inertial electrostatic confinement (IEC) devices use a 10-200 kV voltage difference to accelerate ions through a 0.1-10 mTorr background gas in a spherical or cylindrical geometry. The detailed investigation of a gridded IEC device using DD fuel has resulted in several surprises that have greatly altered our perception of how these systems operate. It was found that there are at least 4 major misconceptions that have been in place for over 15 years on how such IEC systems operate. These misconceptions range all the way from what energetic ion is causing the majority of fusions, to the energy and charge state of the reacting ions. Experimental results will illustrate some of the surprising reactions that are taking place in DD gridded system.

The study of the profiles of velocity and fluid flow rate in porous media with cylindrical geometries were made, using Maple, and the results were obtained in terms of the Bessel Functions. Some of them were the generalized forms of the Haugen-Poiseuille Law. The results could be applied to synthetic media such as zeolites. Only newtonian fluids were considered, but it’s possible to consider non newtonian fluids in the future investigations.

In this article, we present a dynamic phase transition and stability analysis for the Cahn-Hilliard equations in cylindrical geometry. Two types of phase transitions (the continuous type and the jump type) are determined explicitly in terms of relevant physical and geometric parameters.

Organogenesis involves extensive and dynamic changes of tissue shape during development. It is associated with complex morphogenetic events that require enormous tissue plasticity and generate a large variety of transient three-dimensional geometries that are achieved by global tissue responses. Nevertheless, such global responses are driven by tight spatio-temporal regulation of the behaviours of individual cells composing these tissues. Therefore, the development of image analysis tools that allow for extraction of quantitative data concerning individual cell behaviours is central to study tissue morphogenesis. There are many image analysis tools available that permit extraction of cell parameters. Unfortunately, the majority are developed for tissues with relatively simple geometries such as flat epithelia. Problems arise when the tissue of interest assumes a more complex three-dimensional geometry. Here, we use the endothelium of the developing zebrafish dorsal aorta as an example of a tissue with cylindrical geometry and describe the image analysis routines developed to extract quantitative data on individual cells in such tissues, as well as the image acquisition and sample preparation methodology. This article is part of the Theo Murphy meeting issue ‘Mechanics of development’.

A method for implementing cylindrical coordinates in the Athena magnetohydrodynamics (MHD) code is described. The extension follows the approach of Athena's original developers and has been designed to alter the existing Cartesian-coordinates code as minimally and transparently as possible. The numerical equations in cylindrical coordinates are formulated to maintain consistency with constrained transport, a central feature of the Athena algorithm, while making use of previously implemented code modules such as the Riemann solvers. Angular-momentum transport, which is critical in astrophysical disk systems dominated by rotation, is treated carefully. We describe modifications for cylindrical coordinates of the higher-order spatial reconstruction and characteristic evolution steps as well as the finite-volume and constrained transport updates. Finally, we present a test suite of standard and novel problems in one-, two-, and three-dimensions designed to validate our algorithms and implementation and to be of use to other code developers. The code is suitable for use in a wide variety of astrophysical applications and is freely available for download on the web.

We report our preliminary results in developing a new cell-centered control volume Lagrangian scheme for solving Euler equations of compressible gas dynamics in cylindrical coordinates. Based on a local coordinate transform strategy, the scheme can preserve one-dimensional spherical symmetry in a two-dimensional cylindrical geometry when computed on an equal-angle-zoned initial grid. Unlike many previous area weighted schemes that possess the spherical symmetry property, our scheme is discretized on the true volume and it can preserve the conservation property for all the conserved variables including density, momentum and total energy. Preliminary two dimensional numerical examples in cylindrical coordinates are presented to demonstrate the performance of the scheme in terms of symmetry, accuracy and non-oscillatory properties.

A comparative friction study of tooling dies with a simple internal cylindrical geometry has been performed. The purpose of the experiment consist of studying the influence of the surface characteristics of tooling dies on the frictional behaviour in a micro bulk forming operation. This research will seek to contribute with knowledge in the field of the category of structural size effects. By evaluating and benchmarking three different surface topographies, in an O1 and an O2 millimetre cylindrical forming-die, it is expected that frictional performance and forming limits can be evaluated, with the option of extracting general guidelines for evaluation of surface characteristics for dies utilized for micro-forming. The DCE test will be supported by numerical analysis in order to determine the friction factor.

The self-assembly of gyroid-forming diblock copolymers confined in cylindrical geometry is studied using a combination of computer simulations and experiments. The simulations, based on a system qualitatively representative of poly(styrene-b-isoprene), are performed with cylindrical nanopores of different diameter (D) and surface selectivity. The effects of the pore size and surface selectivity on morphology are systematically investigated. Different morphological sequences are predicted for two gyroid-forming diblock copolymers. The experiments are carried out on two gyroid-forming poly(styrene-b-dimethylsiloxane) block copolymer samples confined in the core of continuous core−shell nanofibers of different diameters, which are obtained by a coaxial two-fluid electrospinning technique. The internal microphase-separated morphologies of these fibers are investigated by transmission electron microscopy (TEM). Both simulations and experiments demonstrate that a rich variety of structures spontaneously form for the gyroid-forming diblock copolymers, depending on the conditions of cylindrical confinement. Many of these confinement-induced structures are quite different from those of cylinder-forming or lamella-forming block copolymers. Simulations further show that these structures depend sensitively on the block copolymer composition, surface selectivity, and the ratio D/L0 where L0 is the period of the equilibrium gyroid phase. While the simulation and experimental systems are representative of different chemistries, the morphological predictions of simulations are qualitatively consistent with the experimental observations., Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract DAAD-19-02-D-0002), United States. Army Research Office

The effect of helical driven current on the m = 2/n = 1 tearing mode is studied numerically in a cylindrical geometry using the method of reduced magneto-hydro-dynamic simulation. The results show that the local persistent helical current drive from the beginning time can be applied to control the tearing modes, and will cause a rebound effect called flip instability when the driven current reaches a certain value. The current intensity threshold value for the occurrence of flip instability is about 0.00087I0. The method of controlling the development of tearing mode with comparative economy is given. If the local helical driven current is discontinuous, the magnetic island can be controlled within a certain range, and then, the tearing modes stop growing; thus, the flip instability can be avoided. We also find that the flip instability will become impatient with delay injection of the driven current because the high order harmonics have been developed in the original O-point. The tearing mode instability...

A negative corona in air is numerically simulated for the coaxial cylindrical geometry of electrodes. The goal of the investigation is to gain insight into physical processes and physical conditions in the gap that favor the corona-arc transition. An experiment aimed at contrasting calculated and real characteristics is described.

Specialized protective clothing, such as that worn by firefighters, is usually tested only according to standards for the flame resistant fabrics (NFPA 1971). However, these tests often neglect the effects of cylindrical geometry on heat transmission in flame resistant fabrics. This paper deals with methods to develop cylindrical geometry testing apparatus incorporating a novel skin bioheat transfer model to test flame resistant fabrics used in firefighting. Results show that fabrics which shrink during testing can have reduced thermal protective performance compared with the qualities measured with a planar geometry tester. Results of temperature differences between skin simulant sensors of planar and cylindrical testers are also compared. It is concluded that cylindrical geometry has little effect on the heat transfer within uncovered skin simulant.

An analytical solution has been obtained for the one-speed stationary neutron transport problem, in an infinitely long cylinder with anisotropic scattering by the decomposition method. Series expansions of the angular flux distribution are proposed in terms of suitably constructed functions, recursively obtainable from the isotropic solution, to take into account anisotropy. As for the isotropic problem, an accurate closed-form solution was chosen for the problem with internal source and constant incident radiation, obtained from an integral transformation technique and the F N method.

This review deals with immunoassays, immunosensors and DNA sensors based on capillaries. The one-dimensional cylindrical geometry of capillaries offers several advantages over other types of solid supports. Capillary assays are fast, sensitive and easy to automate. The small capillary dimensions permit low consumption of reagents and samples, while capillary walls can act as light waveguides and fluid cells. We review detection schemes developed for capillary-based single-analyte and multi-analyte binding assays and sensors.