bluuebunny/crossref_metadata_2025 huggingface dataset:
Skin Imaging With Infrared Thermography and Confocal Microscopy
Authors: Pirtini C¸etingu¨l Mu¨ge , Herman Cila , Alani Rhoda M.
Published: June 2010

The implementation of in vivo imaging technologies, such as digital photography, dermoscopy and confocal scanning laser reflectance microscopy (CSLM) in dermatology has led to recent improvements in recognizing skin lesions. Specifically, in the case of skin cancer, a key issue is that the rate of cancerous tissue growth and changes in its spatial extent with time are linked to the energy released locally by these uncontrolled metabolic processes. We believe that with a properly designed infrared (IR) imaging and measurement system combined with thermal analysis, one can characterize healthy and diseased tissue. This paper augments our previous work, in which we introduced a computational model to estimate the location and size of lesions using IR imaging data. In this paper, we focus on calibrating the IR camera and correcting its inherent artifacts. Calibration and corrections are first performed on a blackbody object and then on human skin images in order to acquire accurate surface temperature distributions. As future work, in addition to these correction steps, several other steps, such as accounting for emissivity variations will be developed for clinical studies. In addition to IR imaging, images acquired by in vivo confocal scanning laser microscopy are used to examine the structure of the human skin for different skin types. Our aim is to generate additional data necessary for the IR imaging model by further analyzing the 3D structure of healthy tissue and the lesion. Specifically, in clinical studies, confocal images will be used to describe thermal associations with skin lesion and its blood supply in order to refine our transient thermal model of skin tissue.
Computational Modeling of Vapor Chambers With Nanostructured Wicks
Authors: Bozorg-Grayeli E. , Fang C. , Rogacs A. , Goodson K.
Published: June 2010

As the power and heat output of modern CPUs climb ever higher and the interest in compact, passively cooled devices grows, there is an urgent need for thinner and more effective vapor chamber technologies. Nanostructured wick technologies based on oxide and organic nanowires have been proposed as a method of improving heat pipe performance in such applications. This work performs finite difference simulations of a 2D heat pipe accounting for variable porosity in the wick. For heat fluxes of 10 and 100 W/cm2, we find that temperature difference between the evaporator and condenser regions decreases by 10%, which is promising for spreading thermal energy. We find that spatially varying porosity yields improvements in spreading heat throughout the entire wick region. Finally, we observe that boiling is depressed in the evaporator region. These results verify the benefits of nanostructured wicks. This simulation tool provides the groundwork for future studies of 3D flat package heat pipes.
Heat Flux Estimation in a Nonlinear Inverse Heat Conduction Problem With Moving Boundary
Authors: Molavi Hosein , Hakkaki-Fard Ali , Pourshaghaghy Alireza , Molavi Mehdi , Rahmani Ramin K.
Published: June 2010

Estimation of heat flux in the nonlinear heat conduction problem becomes more challenging when the material at the boundary loses its mass due to phase change, chemical erosion, oxidation, or mechanical removal. In this paper, a new gradient-type method with adjoint problem is employed to predict the unknown time-varying heat flux at the receding surface in the nonlinear heat conduction problem. Particular features of this novel approach are discussed and examined. Results obtained by the new method for several test cases are benchmarked and analyzed using the numerical experiments with the simulated exact and noisy measurements. Exceedingly reliable estimation on the heat flux can be obtained from the knowledge of the transient temperature recordings, even in the case with measurement errors. In order to evaluate the performance characteristics of the present inverse scheme, simulations are conducted to analyze the effects of this technique with regard to conjugate gradient method with adjoint problem and variable metric method with adjoint problem. The obtained results show that the present inverse scheme distinguishably accelerates the convergence rate, which approve the well capability of the method for this type of heat conduction problems.
Symbolic Calculation for Free Convection in a Circular Cavity With Porous Material
Authors: Mansour Kamyar
Published: June 2010

We consider the two-dimensional problem of steady natural convection in a circular cavity filled with porous material due to a cosine temperature variation on the boundary. We use Darcy’s law for this cavity filled with porous material. The solution is governed by dimensionless parameter Darcy-Rayleigh number. The solution is expanded for low Darcy-Rayleigh number and extended to 18 terms by computer. Analysis of these expansions allows the exact computation for arbitrarily accuracy up to 50000 figures. Although the range of the radius of convergence is small but Pade approximation leads our result to be good even for higher value of the similarity parameter.
Impinging Jet on a Concave Surface for Aircraft Anti-Icing
Authors: Bianco V. , Manca O. , Nardini S. , Roma M.
Published: June 2010

Ice formation on airplane wing profile is a very dangerous condition because of the change in the profile aerodynamic, so it is necessary to avoid ice formation on the wings. The hardest condition for ice formation are at altitudes between 10.000 and 15.000 ft and at temperature between 0 °C and −15 °C, because they are particularly suitable for ice formation. In this paper an anti-icing system based on hot air impinging jets on internal wing surface is analyzed in order to check the efficiency of the system. A numerical model is given in order to evaluate the thermal and fluid dynamic behaviours of the impinging jet inside the wing panel. A wing profile with an angle of attack of 4.50° is taken into account with a free stream temperature of 258 K. A piccolo tube with a diameter of 1.00 inch and air temperature of 523 K is considered for anti-icing system. A structured mesh is used in the discretization of the computational domain for the two-dimensional and three-dimensional case. A steady state solution with k-ε RNG turbulent model has been found. Numerical simulations of a two and a three dimensional model of an aircraft wing has been carried out taking into account the external convective exchange by means of an average coefficient on the external surface and thermofluidynamic field inside the wing due to the anti-icing system. The analysis is performed by means of the FLUENT code in order to find the optimal geometrical configuration to avoid the ice formation on the external wing surface. Results are presented in terms of stream function and temperature fields, wall temperature profiles along the wing surfaces and air velocity and temperature profiles.
Dropwise Condensation on Surfaces With Graded Hydrophobicity
Authors: Bonner Richard W.
Published: June 2010

Dropwise condensation has shown the ability to increase condensation heat transfer coefficients by an order of magnitude over filmwise condensation. In standard dropwise condensation, liquid droplets forming on a sub-cooled nonwetting surface are removed from the surface by gravitational forces when the droplets reach a critical mass. The dependence on gravity for liquid removal limits the utilization of dropwise condensation in low gravity aerospace applications and horizontal surfaces. Presented in this study is a novel passive mechanism to remove droplets from a condensing surface using a surface energy gradient (wettability gradient) on the condensing surface. The wettability gradient creates a difference in contact angle across droplets condensing on the surface. The difference in contact angle across the droplets causes motion of the droplets to regions of increased wettability, without relying on additional forces. The movement of droplets away from the surface prevents flooding and allows for the condensation of new droplets on the surface. This paper presents an overall description of the wettability gradient mechanism and experimental condensation data acquired on surfaces with wettability gradients. A mechanism for creating the wettability gradients is also described, which involves varying the surface concentration of hydrophobic molecules through a self-assembled monolayer process.
Thermal Measurements of a Rail-Cask-Size Pipe-Calorimeter in Jet Fuel Fires
Authors: Greiner Miles , del Valle Marcelo , Lopez Carlos , Figueroa Victor , Abu-Irshaid Esam
Published: June 2010

A series of fire tests was conducted involving a 2.44-m-(8-ft)-diameter, 4.57-m-(15-ft)-long, 2.54-cm-(1-inch)-wall thickness pipe calorimeter suspended 1-m above a 7.93-m-diameter pool that contained 7.57 m3 (2000 gallons) of jet fuel. The wind conditions, calorimeter temperature, participating media temperature and speed, and radiant heat flux, were measured at several locations as functions of time in three fire tests. The first two had relatively light winds and lasted roughly 40 minutes, while the third had much stronger winds and consumed the fuel in 25 minutes. The purpose of this paper is to describe the experimental facilities and certain fire characteristics. The large amount of data acquired cannot be fully presented in this paper. A website is available by contacting the first author so that the full data set may be used to quantitatively benchmark large-fire simulations and models.
Effect of Relativistic Transformation Methods on the Solutions of the Damped Wave Conduction and Relaxation Equation in Semi-Infinite Medium
Authors: Sharma Kal Renganathan
Published: June 2010

The expression for transient temperature during damped wave conduction and relaxation developed by Baumeister and Hamill by the method of Laplace transforms was further integrated. A Chebyshev polynomial approximation was used for the integrand with modified Bessel composite function in space and time. Telescoping power series leads to more useful expression for transient temperature. By the method of relativistic transformation the transient temperature during damped wave conduction and relaxation was developed. There are three regimes to the solution. A regime comprising of Bessel composite function in space and time and another regime comprising of modified Bessel composite function in space and time. The temperature solution at the wave front was also developed. The solution for transient temperature from the method of relativistic transformation is compared side by side with the solution for transient temperature from the method of Chebyshev economization. Both solutions are within 12% of each other. For conditions close to the wave front the solution from the Chebyshev economization is expected to be close to the exact solution and was found to be within 2% of the solution from the method of relativistic transformation. Far from the wave front, i.e., close to the surface the numerical error from the method of Chebyshev economization is expected to be significant and verified by a specific example. The solution for transient surface heat flux from the parabolic Fourier heart conduction model and the hyperbolic damped wave conduction and relaxation models are compared with each other. For τ> 1/2 the parabolic and hyperbolic solutions are within 10% of each other. The parabolic model has a “blow-up” at τ→0 and the hyperbolic model is devoid of singularities. The transient temperature from the Chebyshev economization is within an average of 25% of the error function solution for the parabolic Fourier heat conduction model. A penetration distance beyond which there is no effect of the step change in the boundary is predicted using the relativistic transformation model.
A New Criterion for the Onset of Liquid Entrainment From a Stratified Two-Phase Region Through a Small Branch
Authors: Ahmed Mahmoud , Ali Ahmed Hamza H.
Published: June 2010

A new criterion has been developed to predict the onset of liquid (heavier fluid) entrainment from a stratified two-phase region through single and dual branches mounted on a vertical wall. This criterion was based on the local instability of the interface between two fluids due to the suction effect associated with the discharging of the lighter fluid. To validate the criterion, a three-dimensional model has been developed to predict the critical height at the onset of liquid entrainment. Comparisons between the theoretical critical heights with the available experimental data demonstrated a very good concurrence between the predicted and the measured values for both single and dual branches. This indicated that the onset of liquid entrainment mechanism occurs due to local flow instability of the interface analogous to Taylor instability.
Boiling Enhancements by Anodizing and Pre-Boiling in Nanofluid
Authors: Huang Chen-Kang , Lee Chih-Wei
Published: June 2010

Numerous methods, such as sintered or machined surface, have been proposed to enhance the boiling performance. On the other hand, nanofluids are also reported to increase the convective heat transfer and become attractive in many engineering applications. In this study, anodizing was tried to produce porous structure on the heater surface to enhance the boiling performance. Two electrolyes, phosphoric acid and oxalic acid, were used. It was found the anodized pores prepared by oxalic acid were smaller. However, the phosphoric acid anodized surface exhibited a CHF increment by 40% with almost no superheat increment. A nanofluid pre-boiling process was also proposed. An aluminum wire was used as the heater to boil nanofluid for a certain time at a certain heat flux. 0.1 wt% TiO2 nanofluid was used as the working fluid during the pre-boiling process. The wire then went on being the heater for pure water. It is found that aluminum wires exhibit boiling enhancement after preboiling in nanofluid. The most effective process heat flux and duration were found experimentally. The experimental results showed an 11° decrease of the surface superheat. According to SEM photos, two layers were deposited on the aluminum surface. The top layer is more like clusters of deposited nanoparticles, and the layer could be dissolved into water when perform subsequent pure water boiling. The other layer located beneath is more condensed and reliable. It is believed that the second layer could be the main mechanism to exhibit the boiling enhancement.
Moving Heat Sources in a Half Space: Effect of Source Geometry
Authors: Akbari Mohsen , Sinton David , Bahrami Majid
Published: June 2010

The time dependent temperature distribution due to a moving plane heat source of hyperelliptical geometry is analytically studied in this work. The effect of the heat source shape is investigated starting from the general solution of a moving heat source on a half space. Selecting the square root of the heat source area as a length scale, it is observed that the temperature distribution becomes a weak function of the heat source shape. Variation of temperature field with respect to the source aspect ratio, velocity and depth is studied. The analysis presented in this work is valid for both transient and steady-state conditions. In addition, the hyperellipse formulation provided here covers a wide range of shapes including star, rhombic, ellipse, circle, square, rectangle and rectangle with rounded corners.
Computer Assisted Simulation Model in Cryosurgery for Prostate Tumor
Authors: Chen Chih-Wei , Kou Hong-Sen , Liu Hsueh-Erh , Chuang Cheng-Keng , Wang Li-Jen
Published: June 2010

Cryosurgery is also called as cryoablation or cryoleision. The third generation of cryo-machine use argon gas for cooling and helium for rewarming to destroy cancer cells. The probes may be put into the tumor during surgery or through the skin (percutaneously). After cryosurgery, the frozen tissue thaws and is either naturally absorbed by the body (for internal tumors), or it dissolves and forms a scab (for external tumors). The main purpose of this paper is to establish a preliminary computer assisted simulation in prostate tumor cryosurgery. A radiologist and an urologist in a medical center in addition to the engineering specialist from the university participated in this interdisciplinary research program. The first step of this simulation protocol is to trim hundreds of two-dimensional medical imaging photos from a patient through the imaging reconstructive software into building a three-dimensional solid modeling. The image data for each patient can be obtained from the x-ray computed tomography (CT), or magnetic resonance imaging (MRI) in the imaging department of hospital. It has successfully built up the related knowledge to overcome the complicacy between the medical imaging modalities and engineering graphic solid modeling with high resolution. It is worthy to mention here that the present solid modeling of prostate can demonstrate the variable diameters and courses of the prostate urethra in vivo. The second step focuses on thermal calculation. So far, there has been no existing commercial software for the specific purpose of the bioheat transfer problem. Hence, user subroutines must be added to the existing commercial software to simulate the clinical situation of cryosurgery. For example, the occurrence of phase change during some specified temperature range and the latent heat of fusion are also incorporated into bio-heat transfer model. It has successfully incorporated bioheat transfer model into the software program to fit the reality in thermal medicine. The third step supplies the data and knowledge concerned with the position of a tumor and the related mechanism of metabolism of living tissue and vessels. The number of probes, the position of each probe, and the operating time of each probe will be explored to ensure a complete killing of the tumor tissue while saving as much healthy surrounding tissue as possible. In this study, the three-dimensional transient temperature distributions based on cryosurgery for prostate tumors have been performed for several cases to find the optimal operating conditions. Different cryoprobes with different freezing time are considered to find the temperature distribution. The simulation results for cryosurgery of prostate tumors will be supplied for practicing physicians as reference to greatly improve the effectiveness of cryosurgery.
Numerical Analysis on the Radiant Characteristics of Three-Dimensional Random Rough Surfaces
Authors: Feng Yanhui , Liu Wei , Zhang Xinxin
Published: June 2010

In the area of micro- and nano-scale radiation heat transfer, the radiant characteristics of rough surfaces have drawn increasing attention. In this paper, three-dimensional Gaussian random rough surfaces were created by the Monte Carlo simulation method. Ray tracing method combined with the Kirchhoff approximation was employed to analyze the shadowing effect of random surfaces with different roughness. The relative scattering intensity from rough surfaces was further investigated by the Fresnel law. The results indicated that the peak of the relative scattering intensity occurred at the anti-scattering angle and the scattering distributions were continuous. With increasing surface roughness, the height of the peak became lower, the width of distribution became wider, and the distribution range of the scattering angle and the azimuth of the reflection electromagnetic waves increased. Furthermore, the relative scattering intensity concentrated in the vicinity of the anti-scattering angle and the largest scattering intensity occurred in the specular direction. Taking into account of the effects of polarization state and wavelength of incidence waves, it was shown that the relative scattering intensity of s polarized incident wave was slightly larger than that of p polarization, while the relative scattering intensity became stronger as the wavelength increased.
Raman Thermometry Measurements and Thermal Simulations for MEMS Bridges at Pressures From 0.05 to 625 Torr
Authors: Phinney Leslie M. , Serrano Justin R. , Piekos Edward S. , Torczynski John R. , Gallis Michael A. , Gorby Allen D.
Published: June 2010

This paper reports on experimental and computational investigations into the thermal performance of microelectro-mechanical systems (MEMS) as a function of the pressure of the surrounding gas. High spatial resolution Raman thermometry was used to measure the temperature profiles on electrically heated, polycrystalline silicon bridges that are nominally 10 μm wide, 2.25 μm thick, and either 200 or 400 μm long in nitrogen atmospheres with pressures ranging from 0.05 to 625 Torr. Finite element modeling of the thermal behavior of the MEMS bridges is performed and compared to the experimental results. Noncontinuum gas effects are incorporated into the continuum finite element model by imposing temperature discontinuities at gas-solid interfaces that are determined from noncontinuum simulations. The results indicate that gas-phase heat transfer is significant for devices of this size at ambient pressures but becomes minimal as the pressure is reduced below 5 Torr. The model and experimental results are in qualitative agreement, and better quantitative agreement requires increased accuracy in the geometrical and material property values.
Simulation of Heat Transfer in Moving Granular Material by the Discrete Element Method With Special Emphasis on Inner Particle Heat Transfer
Authors: Rickelt S. , Kruggel-Emden H. , Wirtz S. , Scherer V.
Published: June 2010

Physical processes involving static or dynamic granular assemblies are best modeled on the particle scale by Discrete Element Methods (DEM) rather than continuum approaches. Due to the high computational effort of DEM simulations, present studies assume the inner particle temperature to be spatially uniform and neglect the inner particle heat transfer. For this reason the Radial Temperature Model was introduced [1, 2] It assumes radial temperature distributions within the particles and is based on an analytical solution of the heat conduction equation in a spherical particle. The scope of this paper is to present the further development of the Radial Temperature Model that allows to simulate granular systems of particles of different sizes and materials, enabling the use of DEM in various applications. The contact heat transfer is modeled making additional material-specific data unnecessary. It is shown that a very good accuracy for the contact heat transfer between different spherical particles is achieved for binary contacts. DEM simulations were performed using the Radial Temperature Model and uniform particle temperatures, respectively. The results demonstrate that the Radial Temperature Model that has been developed and incorporated in the Discrete Element Method allows for an improved calculation of the transient thermal behavior of granular assemblies even for large numbers of particles.
Optimal Shape Design for Heat Conduction Problems Using NURBS
Authors: Fakhrabadi Farbod , Kowary Farshad
Published: June 2010

This article presents an optimal shape design methodology for heat conduction problems. In this study, the shape of the conductive medium is parameterized by means of non-uniform rational B-spline (NURBS) surfaces, and their control points represent the design variables. The conductive domain is discretized by choosing the parameters of NURBS surfaces as generalized curvilinear coordinates, and the heat conduction equation is solved using the finite difference method. The simplified conjugate-gradient method (SCGM) is used as the optimization method to obtain the optimal shape and adjust the design variables intelligently. The methodology is demonstrated by optimizing the profile of a straight fin with the objective of enhancing heat transfer rate and reducing the fin mass.
Optimal Shape Design for Heat Convection Problems Using NURBS
Authors: Fakhrabadi Farbod , Kowsary Farshad
Published: June 2010

This article presents an optimal shape design methodology for heat convection problems. In this study, the shape of the convective medium is parameterized by means of non-uniform rational B-spline (NURBS) surfaces, and their control points represent the design variables. The convective domain is discretized by choosing the parameters of NURBS surfaces as generalized curvilinear coordinates, and the conservation equations are solved using the finite difference method. The simplified conjugate-gradient method (SCGM) is used as the optimization method to obtain the optimal shape and adjust the design variables intelligently. The methodology is demonstrated by optimizing the shape profile of a natural convective cavity with the objective of reducing the maximum wall temperature.
CFD Study for Air Distribution in Hydrogen Reformer Furnace
Authors: Zhou Ping , Wu Bin , Hu Yuzhu , Zheng Dezhi , Fleitz Jeff , Trajkovski Robert , Zhou Chenn Q.
Published: June 2010

The uniform flow rate is a fundamental requirement in the design of air distributors for the hydrogen reformer furnace. Constraints of flow rate primarily demands on configuration of air distributors. Particularly for the air with different temperature, velocity and pressure, an even distribution of air distributors is especially important. Air distributors containing one inlet and eleven outlets are connected with burners so that uniform flow rate of each outlet is required. Based on CFD (Computational Fluid Dynamics) method, temperature, velocity and pressure distribution in the air distributors are simulated. The results show that flow rate is sensitive to the rate of pressure and velocity change but not for temperature change. The maldistribution of each outlet cannot accord with engineering standard. So, it is necessary to take some methods to decrease the maldistribution of each outlet. The dampers exist at each outlet are controlled individually. Hence, the flow rate can be constrained by adjust pressure according to the proportion of maldistribution.
Critical Conditions for Fire-Induced Smoke Confinement by Air Curtain in Long Channels
Authors: Ji Jie , Zhong Wei , Huo Ran , Sun Jinhua
Published: June 2010

The air curtain can be adopted to slow down or stop smoke spread, in case of channel fires, with no influence of the normal usage of the channels and on the human evacuation. The flow field of air curtain jet from ceiling to floor was divided into 3 sections, i.e. the section of impinging mixing, non-isothermal jet and impinging floor and the theoretical analysis of fire-induced smoke control by air curtain in long channels was carried out. The formulas of the critical conditions for absolutely preventing smoke from intruding the protected side were obtained. With the Realizable k–ε model and the numerical solutions of the formulas as the initial and boundary conditions, an application example was simulated. Results showed that the three-section analysis method was reasonable and the simulated results verified the rationality of the theoretical prediction model.
Investigating Double Diffusive Convection in an Inclined Rectangular Porous Enclosure Subjected to Magnetic Field
Authors: Moghadassian Behnam , Razi Pooyan , Shokouhmand Hossein
Published: June 2010

The problem of double diffusive convection in an inclined rectangular enclosure filled with a uniform porous medium at the presence of magnetic field has been studied. The constant temperature and concentration are imposed along two opposing walls, while the other two walls are adiabatic and impermeable to mass transfer. Non-dimensional governing equations are solved using the finite difference method. The representative results illustrates streamline, temperature, concentration and density contours as well as non-dimensional parameters of heat and mass transfer versus changes in magnitude and direction of magnetic field, buoyancy ratio, Darcy number and inclination angle of the enclosure. One of the main results is that average Nusselt and Sherwood numbers and flow characteristics depend significantly on the buoyancy ratio, Darcy number and direction of the magnetic field. Also it is observed that there is a decreasing trend in the average Nusselt and Sherwood numbers with increasing strength of the magnetic field.
Self-Organization of Tornado-Like Jets in Flows of Gases and Liquids and the Technologies Utilizing This Phenomenon
Authors: Kiknadze G. I. , Gachechiladze I. A. , Gorodkov A. Yu.
Published: June 2010

Basic results are considered of aerohydrodynamic and thermophysical experiments, in which secondary tornado-like jets (TLJ) are revealed and investigated. These jets are self-organized under conditions of flow past surfaces with three-dimensional recesses (dimples) with a second-order curvilinear surface (TLJS – tornado-like jet surface). Exact solutions are given of unsteady-state Navier–Stokes and continuity equations, which describe the TLJ. The impact is considered, which is made on the flow in dimple by forces forming a flow of new type with built-in secondary tornado-like jets. These forces are absent in the case of flow past initially smooth surfaces. The problems are discussed of reducing the aerohydrodynamic drag on the TLJS, of enhancing the heat and mass transfer with the level of hydraulic loss lagging behind the degree of enhancement, of increasing the critical heat loads under conditions of boiling and supercritical flows of continuous medium past the TLJS, of preventing cavitation damage to the TLJS in hydraulic apparatuses, of reducing the adsorption of foreign matter on these surfaces, of reducing the friction between TLJS rubbing against one another, and of raising the efficiency of facilities for tornadolike conversion of energy of renewable low-potential sources. It is demonstrated that the obtained exact solutions of Navier–Stokes and continuity equations provide an adequate model of generation and evolution of swirling flow of blood in human blood circulation system, which enables one to proceed to development of safe and effective devices for substitution of organs in cardiac surgery. An inference is made about the universality of the flow of new type for raising the efficiency of technologies involving flows of various media.
Identifying critical success factors for designing selection processes into postgraduate specialty training: the case of UK general practice
Authors: Plint Simon , Patterson Fiona
Published: June 2010

The UK national recruitment process into general practice training has been developed over several years, with incremental introduction of stages which have been piloted and validated. Previously independent processes, which encouraged multiple applications and produced inconsistent outcomes, have been replaced by a robust national process which has high reliability and predictive validity, and is perceived to be fair by candidates and allocates applicants equitably across the country. Best selection practice involves a job analysis which identifies required competencies, then designs reliable assessment methods to measure them, and over the long term ensures that the process has predictive validity against future performance. The general practitioner recruitment process introduced machine markable short listing assessments for the first time in the UK postgraduate recruitment context, and also adopted selection centre workplace simulations. The key success factors have been identified as corporate commitment to the goal of a national process, with gradual convergence maintaining locus of control rather than the imposition of change without perceived legitimate authority.
Pathogenesis and treatment of chronic rhinosinusitis
Authors: Wood Andrew J , Douglas Richard G
Published: June 2010

Chronic rhinosinusitis (CRS) is one of the most common diseases in western societies, causing significant morbidity and resulting in great financial cost. Some patients suffer persistent or recurrent symptoms despite receiving optimal medical and surgical treatment. The recent publication of revised diagnostic criteria and management guidelines will assist both clinical research and practice. Multiple theories have been advanced regarding the underlying pathogenesis including allergy, bacterial or fungal infection, genetic predisposition and structural anomalies, but at present the majority of cases are still considered idiopathic. Recent studies have shown that traditional laboratory culture techniques may fail to detect microorganisms growing within biofilms or within host mucosal cells. Both bacteria and fungi possess a number of mechanisms for both the evasion and modulation of host immune responses, including the formation of biofilms and the production of superantigens. Historically, treatments such as antibiotics that had been directed at putative causative agents have often been disappointing. There are, however, a broad range of medical and surgical therapies with proven efficacy available to the treating physician. Endoscopic surgical management is evolving rapidly, and there have been pronounced improvements in outcome and reduction in the risk of complications. Recent advances in the understanding of the pathogenesis of this condition have led to some promising therapeutic developments, particularly in respect to topical treatments. Despite improvements in therapy, CRS remains a challenging condition to manage.
Large igneous provinces (LIPs), giant dyke swarms, and mantle plumes: significance for breakup events within Canada and adjacent regions from 2.5 Ga to the PresentThis article is one of a selection of papers published in this Special Issue on the the theme Lithoprobe—parameters, processes, and the evolution of a continent.Lithoprobe Contribution 1482. Geological Survey of Canada Contribution 20100072.
Authors: Ernst Richard , Bleeker Wouter
Published: June 2010

Large igneous provinces (LIPs) are high volume, short duration pulses of intraplate magmatism consisting mainly of flood basalts and their associated plumbing system, but also may include silicic components and carbonatites. Many LIPs have an associated radiating diabase dyke swarm, which typically converges on a cratonic margin, identifies a mantle plume centre, and is linked to breakup or attempted breakup to form that cratonic margin. We hypothesize that every major breakup margin in Canada can be associated with a LIP, and we attempt to identify this LIP. To this end, we focus mainly on high-precision age determinations and the distribution of diabase dyke swarms, which are uniquely valued for preserving the record of magmatic events. The analysis extends from the Phanerozoic to the Neoarchean, but our most complete information is for the Superior craton. There, events at 2.50–2.45, 2.22–2.17, and 2.12–2.08 Ga (LIP and plume) are linked with rifting and breakup or attempted breakup of the south-southeastern, northeastern, and southern margins, respectively. Events at 2.00–1.97 Ga are probably linked with the northern margin (Ungava promontory), while the Circum-Superior event at ca. 1.88 Ga is linked to the north to northwestern margins during a time of Manikewan Ocean closure. Similar linkages for other cratons of North America improve understanding of the breakup history to help identify which blocks were nearest neighbours to Canadian crustal blocks in Precambrian supercontinents. Such interpretations provide a framework for interpreting other geological features of these margins to further test models for the timing and location of breakup.
BLACK HOLE AS AN INFORMATION ERASER
Authors: KIM HYEONG-CHAN , LEE JAE-WEON , LEE JUNGJAI
Published: June 2010

We discuss the identity of black hole entropy and show that the first law of black hole thermodynamics, in the case of a Schwarzschild black hole, can be derived from Landauer's principle by assuming that the black hole is one of the most efficient information erasers. The term "most efficient" implies that maximal information will be erased for a given amount of work. We calculate the discrete mass spectra and the entropy of a Schwarzschild black hole assuming that the black hole processes information in unit of bits. The black hole entropy acquires a subleading contribution proportional to the logarithm of its mass-squared in addition to the usual mass-squared term without an artificial cutoff. We also argue that the minimum of the black hole mass is [Formula: see text]
A REVIEW OF QUANTUM GRAVITY AT THE LARGE HADRON COLLIDER
Authors: CALMET XAVIER
Published: June 2010

The aim of this paper is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing the emission of gravitons (massless or massive) at the LHC and to the production of small quantum black holes.
ANDERSON TRANSITIONS: CRITICALITY, SYMMETRIES AND TOPOLOGIES
Authors: Mirlin A. D. , Evers F. , Gornyi I. V. , Ostrovsky P. M.
Published: June 2010

The physics of Anderson transitions between localized and metallic phases in disordered systems is reviewed. We focus on the character of criticality as well as on underlying symmetries and topologies that are crucial for understanding phase diagrams and the critical behavior.
INTRINSIC ELECTRON LOCALIZATION IN MANGANITES
Authors: Ramakrishnan T. V.
Published: June 2010

We mention here an unusual disorder effect in manganites, namely the ubiquitous hopping behavior for electron transport observed in them over a wide range of doping. We argue that the implied Anderson localization is intrinsic to manganites, because of the existence of polarons in them which are spatially localized, generally at random sites (unless there is polaron ordering). We have developed a microscopic two fluid lb model for manganites, where l denotes lattice site localized l polarons, and b denotes band electrons. Using this, and the self-consistent theory of localization, we show that the occupied b states are Anderson localized in a large range of doping due to the scattering of b electrons from l polarons. Numerical simulations which further include the effect of long range Coulomb interactions support this, as well the existence of a novel polaronic Coulomb glass. A consequence is the inevitable hopping behaviour for electron transport observed in doped insulating manganites.
ANDERSON LOCALIZATION VS. MOTT–HUBBARD METAL–INSULATOR TRANSITION IN DISORDERED, INTERACTING LATTICE FERMION SYSTEMS
Authors: Byczuk Krzysztof , Hofstetter Walter , Vollhardt Dieter
Published: June 2010

We review recent progress in our theoretical understanding of strongly correlated fermion systems in the presence of disorder. Results were obtained by the application of a powerful nonperturbative approach, the dynamical mean-field theory (DMFT), to interacting disordered lattice fermions. In particular, we demonstrate that DMFT combined with geometric averaging over disorder can capture Anderson localization and Mott insulating phases on the level of one-particle correlation functions. Results are presented for the ground state phase diagram of the Anderson–Hubbard model at half-filling, both in the paramagnetic phase and in the presence of antiferromagnetic order. We find a new antiferromagnetic metal which is stabilized by disorder. Possible realizations of these quantum phases with ultracold fermions in optical lattices are discussed.
SCALING OF VON NEUMANN ENTROPY AT THE ANDERSON TRANSITION
Authors: Chakravarty Sudip
Published: June 2010

Extensive body of work has shown that for the model of a non-interacting electron in a random potential there is a quantum critical point for dimensions greater than two — a metal–insulator transition. This model also plays an important role in the plateau-to-plateu transition in the integer quantum Hall effect, which is also correctly captured by a scaling theory. Yet, in neither of these cases the ground state energy shows any non-analyticity as a function of a suitable tuning parameter, typically considered to be a hallmark of a quantum phase transition, similar to the non-analyticity of the free energy in a classical phase transition. Here we show that von Neumann entropy (entanglement entropy) is non-analytic at these phase transitions and can track the fundamental changes in the internal correlations of the ground state wave function. In particular, it summarizes the spatially wildly fluctuating intensities of the wave function close to the criticality of the Anderson transition. It is likely that all quantum phase transitions can be similarly described.
Detecting Chemical Hazards with Temperature-Programmed Microsensors: Overcoming Complex Analytical Problems with Multidimensional Databases
Authors: Meier Douglas C. , Raman Baranidharan , Semancik Steve
Published: June 2010

Complex analytical problems, such as detecting trace quantities of hazardous chemicals in challenging environments, require solutions that most effectively extract relevant information about a sample's composition. This review presents a chemiresistive microarray–based approach to identifying targets that combines temperature-programmed elements capable of rapidly generating analytically rich data sets with statistical pattern recognition algorithms for extracting multivariate chemical fingerprints. We describe the chemical-microsensor platform and discuss its ability to generate orthogonal data through materials selection and temperature programming. Visual inspection of data sets reveals device selectivity, but statistical analyses are required to perform more complex identification tasks. Finally, we discuss recent advances in both devices and algorithms necessary to deal with practical issues involved in long-term deployment. These issues include identification and correction of signal drift, challenges surrounding real-time unsupervised operation, repeatable device manufacturability, and hierarchical classification schemes designed to deduce the chemical composition of untrained analyte species.
Nanoscale Control and Manipulation of Molecular Transport in Chemical Analysis
Authors: Bohn Paul W.
Published: June 2010

The ability to understand and control molecular transport is critical to numerous chemical measurement strategies, especially as they apply to mass-limited samples in nanometer-scale structures. The characteristics of nanoscale structures and devices highlighted in the examples discussed in this article include enhanced mass transport, accessing novel physical behavior, large surface-to-volume ratio, diminished background signals, and the fact that molecular characteristics can dominate the behavior of the structure. The control of nanoscale transport is physically embodied in different structures and experiments. Those structures and experiments highlighted here are featured because of their centrality (nanochannels and nanopores), their connection to more familiar macroscale phenomena (nanoelectrodes), and/or their ability to introduce control (stimulus-responsive materials) or because they represent especially interesting possibilities (stochastic sensing structures).
Miniature Mass Spectrometers
Authors: Ouyang Zheng , Cooks R. Graham
Published: June 2010

We discuss miniaturization in mass spectrometry in terms of the mass analyzer, the mass spectrometer, and the total analytical system. Mass analyzer miniaturization has focused on ion traps. Decreases in mass analyzer size facilitate reduction of the sizes of the other components of a miniature mass spectrometer, especially the radio frequency electronics and vacuum system. Appropriate sample introduction systems are needed for performance optimization. The criteria by which a miniature mass spectrometer is judged include adequate performance in the traditional areas of resolution, detection limits, and specificity; ruggedness; reliability; and fully autonomous operation. Our discussion of the total analytical system emphasizes the removal of the bottleneck of sample preparation and suggests a solution to the combination of sampling, preconcentration, and ionization: ambient ionization methods. We also describe current miniature mass spectrometers.
Role of Analytical Chemistry in Defense Strategies Against Chemical and Biological Attack
Authors: Janata Jiri
Published: June 2010

Analytical chemistry plays a role in the two strategies of defense against chemical or biological weapons that are discussed in this review: the detect-to-protect and the prevent-and-detect strategies. The detect-to-protect method, which is based on detection of a known chemical agent with a specific chemical sensor designed for said agent, has serious flaws. I argue that this approach should be replaced with the prevent-and-detect strategy. Such a change in the defense paradigm would require reallocation of resources, but it is necessary for effective protection of enclosed civilians from chemical and/or biological attack.
Applications of Aptamers as Sensors
Authors: Cho Eun Jeong , Lee Joo-Woon , Ellington Andrew D.
Published: June 2010

Aptamers are ligand-binding nucleic acids whose affinities and selectivities can rival those of antibodies. They have been adapted to analytical applications not only as alternatives to antibodies, but as unique reagents in their own right. In particular, aptamers can be readily site-specifically modified during chemical or enzymatic synthesis to incorporate particular reporters, linkers, or other moieties. Also, aptamer secondary structures can be engineered to undergo analyte-dependent conformational changes, which, in concert with the ability to specifically place chemical agents, opens up a wealth of possible signal transduction schemas, irrespective of whether the detection modality is optical, electrochemical, or mass based. Finally, because aptamers are nucleic acids, they are readily adapted to sequence- (and hence signal-) amplification methods. However, application of aptamers without a basic knowledge of their biochemistry or technical requirements can cause serious analytical difficulties.
Attractors for Nonautonomous Parabolic Equations without Uniqueness
Authors: The Anh Cung , Dinh Binh Nguyen
Published: June 2010

Using the theory of uniform global attractors of multivalued semiprocesses, we prove the existence of a uniform global attractor for a nonautonomous semilinear degenerate parabolic equation in which the conditions imposed on
the nonlinearity provide the global existence of a weak solution, but not uniqueness. The Kneser property of solutions is also studied, and as a result we obtain the connectedness of the uniform global attractor.
Trypsin Isoinhibitors with Antiproliferative Activity toward Leukemia Cells fromPhaseolus vulgariscv “White Cloud Bean”
Authors: Sun Jian , Wang Hexiang , Ng Tzi Bun
Published: June 2010

A purification protocol that comprised ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75 was complied to isolate two trypsin inhibitors fromPhaseolus vulgariscv “White Cloud Bean”. Both trypsin inhibitors exhibited a molecular mass of 16 kDa and reduced the activity of trypsin with an value of about 0.6 M. Dithiothreitol attenuated the trypsin inhibitory activity, signifying that an intact disulfide bond is indispensable to the activity. [Methyl-] thymidine incorporation by leukemia L1210 cells was inhibited with an value of 28.8 M and 21.5 M, respectively. They were lacking in activity toward lymphoma MBL2 cells and inhibitory effect on HIV-1 reverse transcriptase and fungal growth when tested up to 100 M.