bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid High Temperature Solar Thermal Biomass Gasification in a Prototype Cavity Reactor
Authors: Lichty Paul , Perkins Christopher , Woodruff Bryan , Bingham Carl , Weimer Alan
Published: January 2010

High temperature biomass gasification has been performed in a prototype concentrated solar reactor. Gasification of biomass at high temperatures has many advantages compared with historical methods of producing fuels. Enhancements in overall conversion, product composition ratios, and tar reduction are achievable at temperatures greater than 1000°C. Furthermore, the utilization of concentrated solar energy to drive these reactions eliminates the need to consume a portion of the product stream for heating and some of the solar energy is stored as chemical energy in the product stream. Experiments to determine the effects of temperature, gas flow rate, and feed type were conducted at the high flux solar furnace at the National Renewable Energy Laboratory, Golden, CO. These experiments were conducted in a reflective cavity multitube prototype reactor. Biomass type was found to be the only significant factor within a 95% confidence interval. Biomass conversion as high as 68% was achieved on sun. Construction and design considerations of the prototype reactor are discussed as well as initial performance results.
Full Rotatability and Singularity of Six-Bar and Geared Five-Bar Linkages
Authors: Ting Kwun-Lon , Wang Jun , Xue Changyu , Currie Kenneth R.
Published: January 2010

Full rotatability identification is a problem frequently encountered in linkage analysis and synthesis. The full rotatability of a linkage refers to a linkage, in which the input may complete a continuous rotation without the possibility of encountering a dead center position. In a complex linkage, the input rotatability of each branch may be different. This paper presents a unified and comprehensive treatment for the full rotatability identification of six-bar and geared five-bar linkages, regardless of the choice of input joints or reference link. A general way to identify all dead center positions and the associated branches is discussed. Special attention and detail discussion is given to the more difficult condition, in which the input is not given through a joint in the four-bar loop or to a gear link. A branch without a dead center position has full rotatability. Using the concept of joint rotation space, the branch of each dead center position, and hence, the branch without a dead center position can be identified. One may find the proposed method to be generally and conceptually straightforward. The treatment covers all linkage inversions.
Effects of Orientation Angles on the Singularity-Free Workspace and Orientation Optimization of the Gough–Stewart Platform
Authors: Jiang Qimi , Gosselin Clément M.
Published: January 2010

The singularity-free workspace of parallel mechanisms is highly desirable in a context of robot design. This work focuses on analyzing the effects of the orientation angles on the singularity-free workspace of the Gough–Stewart platform in order to determine the optimal orientation. In any orientation with ϕ=θ=0 deg and ψ≠±90 deg, the singularity surface becomes a plane coinciding with the base plane. Hence, an analytic algorithm is presented in this work to determine the singularity-free workspace. The results show that the singularity-free workspace in some orientations can be larger than that in the reference orientation with ϕ=θ=ψ=0 deg. However, the global optimal orientation is difficult to determine. Only an approximate optimal orientation is available. The results obtained can be applied to the design or parameter setup of the Gough–Stewart platform.
Analytic Formulation for Kinematics, Statics, and Shape Restoration of Multibackbone Continuum Robots Via Elliptic Integrals
Authors: Xu Kai , Simaan Nabil
Published: January 2010

This paper presents a novel and unified analytic formulation for kinematics, statics, and shape restoration of multiple-backbone continuum robots. These robots achieve actuation redundancy by independently pulling and pushing three backbones to carry out a bending motion of two-degrees-of-freedom (DoF). A solution framework based on constraints of geometric compatibility and static equilibrium is derived using elliptic integrals. This framework allows the investigation of the effects of different external loads and actuation redundancy resolutions on the shape variations in these continuum robots. The simulation and experimental validation results show that these continuum robots bend into an exact circular shape for one particular actuation resolution. This provides a proof to the ubiquitously accepted circular-shape assumption in deriving kinematics for continuum robots. The shape variations due to various actuation redundancy resolutions are also investigated. The simulation results show that these continuum robots have the ability to redistribute loads among their backbones without introducing significant shape variations. A strategy for partially restoring the shape of the externally loaded continuum robots is proposed. The simulation results show that either the tip orientation or the tip position can be successfully restored.
On the Spin Surface of RSSR Mechanisms With Parallel Rotary Axes
Authors: Nawratil Georg
Published: January 2010

Due to Cayley’s theorem the line s∊Σ (=moving system) spanned by the centers of the spherical joints of a revolute-spherical-spherical-revolute linkage generates a surface of degree 8. In the special case of parallel rotary axes of the R-joints the corresponding ruled surface is only of degree 6. Now the point locus of any point X∊Σ\{s} is a surface of order 16 (general case) or of order 12 (special case). Hunt (1978, Kinematic Geometry of Mechanisms, Clarendon, Oxford) suggested that the circularity of this so called spin-surface for the general case is 8 and this was later proved. We demonstrate that the circularity of the spin-surface for the special case is 4 instead of 6 as given in the literature (1994, “The (True) Stewart Platform Has 12 Configurations,” Proceedings of the IEEE International Conference on Robotics and Automation, pp. 2160–2165). As a consequence generalized triangular symmetric simplified manipulators (the three rotary axes need not be coplanar) with two parallel rotary joints can have up to 16 solutions instead of 12 (2006, Parallel Robots, 2nd ed., Springer, New York). We show that this upper bound cannot be improved by constructing an example for which the maximal number of assembly modes is reached. Moreover, we list all parallel manipulators of this type where more than 4×2=8 points are located on the imaginary spherical circle.
Design of Planar Parallel Robots With Preloaded Flexures for Guaranteed Backlash Prevention
Authors: Wei Wei , Simaan Nabil
Published: January 2010

The precision of parallel robots is limited by backlash in their joints. This paper investigates algorithms for designing inexpensive planar parallel robots with prescribed backlash-free workspace. The method of closing the backlash of the actuators uses preloaded flexible joints to replace the passive joints. These flexible joints may be made using standard joints with preloaded springs or by using preloaded flexure joints. Given a norm-bounded wrench acting on the robot, an algorithm is presented for determining the required preload for the flexible joints in order to guarantee backlash-free operation along a path or within a prescribed workspace. An investigation of the effects of the preloaded flexible joints on the stiffness is carried out using performance measures comparing the same robot with or without preloaded joints. These performance measures use an extended stiffness definition based on three noncollinear vertices on the moving platform. This paper presents simulations of the statics, stiffness, and backlash prevention algorithm, followed by experimental validations.
Relationship Among Input-Force, Payload, Stiffness, and Displacement of a 6-DOF Perpendicular Parallel Micromanipulator
Authors: Yue Yi , Gao Feng , Zhao Xianchao , Ge Q. Jeffrey
Published: January 2010

Micromanipulators play an important role in the precision engineering field from optical stages to micro-electromechanical systems for their excellent performances. In this paper, a 6-DOF perpendicular parallel micromanipulator (PPMM) is proposed and its prototype is developed. The isotropy and decoupled characteristics of the 6-DOF PPMM are discussed. The relationship among input-force, payload, stiffness, and displacement (IPSD) of the 6-DOF PPMM is studied and the model of the relationship among the IPSD is derived in an analytical style. The relation between voltage value of piezoelectric actuator and output displacement is obtained base on an IPSD model. Finally, the simulations by finite element method and the test of the prototype of the 6-DOF PPMM are performed. Compared with the results of simulations and the test, the feasibility of IPSD model is verified. The proposed model is useful for both digital control of the 6-DOF PPMMs and design of the micromanipulators.
Parametric Design of
Parallel Force/Velocity Actuators: Force Distribution
Analysis
Authors: Rabindran Dinesh , Tesar Delbert
Published: January 2010

In this paper we present the force distribution analysis for a dual input actuator called parallel force/velocity actuator (PFVA). We present five physical quantities that are relevant to the design and operation of PFVA-based systems. For each of them we (i) follow a first principles approach to develop a model, (ii) define dimensionless parameters and criteria that indicate the relative distribution of the quantity between the two inputs of the PFVA, (iii) express the basic model in terms of these dimensionless parameters, (iv) provide numerical examples using five candidate designs with commercial off-the-shelf components, (v) investigate the limiting case as the two inputs become more and more kinematically distinct, and (vi) suggest design guidelines based on our analysis. We studied four aspects of PFVA design: (i) mixing of position uncertainties of the two inputs, i.e., force actuator (FA) and velocity actuator (VA), (ii) distribution of static and inertia torques between the inputs for a given output loading condition, (iii) acceleration responsiveness, and lastly, (iv) effective stiffness of the PFVA system with respect to some basic design parameters of the PFVA. As an example result, we observed that the PFVA's effective stiffness will be at least 40% greater than that of the VA if the FA is 85% as efficient as the VA, the FA is 17% less stiff than the VA, and the kinematic scaling between the two inputs (FA and VA) is approximately 11.5. The results we obtained are organized into five design guidelines for the PFVA. To demonstrate the utility of this analysis and the guidelines, we present a design case study that describes a PFVA prototype. The results of this paper assist in better designing PFVA-based systems with a focus on the coupling between the two inputs.
On the Ability of a Cable-Driven Robot to Generate a Prescribed Set of Wrenches
Authors: Bouchard Samuel , Gosselin Clément , Moore Brian
Published: January 2010

This paper presents a new geometry-based method to determine if a cable-driven robot operating in a d-degree-of-freedom workspace (2≤d≤6) with n≥d cables can generate a given set of wrenches in a given pose, considering acceptable minimum and maximum tensions in the cables. To this end, the fundamental nature of the available wrench set is studied. The latter concept, defined here, is closely related to similar sets introduced by Ebert-Uphoff and co-workers (2004, “Force-Feasible Workspace Analysis for Underconstrained, Point-Mass Cable Robots,” IEEE Trans. Rob. Autom., 5, pp. 4956–4962; 2007, “Workspace Optimization of a Very Large Cable-Driven Parallel Mechanism for a Radiotelescope Application,” Proceedings of the ASME IDETC/CIE Mechanics and Robotics Conference, Las Vegas, NV). It is shown that the available wrench set can be represented mathematically by a zonotope, a special class of convex polytopes. Using the properties of zonotopes, two methods to construct the available wrench set are discussed. From the representation of the available wrench set, computationally efficient and noniterative tests are presented to verify if this set includes the task wrench set, the set of wrenches needed for a given task.
Theory and Manufacturing Processes of Solar Nanoantenna Electromagnetic Collectors
Authors: Kotter D. K. , Novack S. D. , Slafer W. D. , Pinhero P. J.
Published: January 2010

The research described in this paper explores a new and efficient approach for producing electricity from the abundant energy of the sun, using nanoantenna (nantenna) electromagnetic collectors (NECs). NEC devices target midinfrared wavelengths, where conventional photovoltaic (PV) solar cells are inefficient and where there is an abundance of solar energy. The initial concept of designing NECs was based on scaling of radio frequency antenna theory to the infrared and visible regions. This approach initially proved unsuccessful because the optical behavior of materials in the terahertz (THz) region was overlooked and, in addition, economical nanofabrication methods were not previously available to produce the optical antenna elements. This paper demonstrates progress in addressing significant technological barriers including: (1) development of frequency-dependent modeling of double-feedpoint square spiral nantenna elements, (2) selection of materials with proper THz properties, and (3) development of novel manufacturing methods that could potentially enable economical large-scale manufacturing. We have shown that nantennas can collect infrared energy and induce THz currents and we have also developed cost-effective proof-of-concept fabrication techniques for the large-scale manufacture of simple square-loop nantenna arrays. Future work is planned to embed rectifiers into the double-feedpoint antenna structures. This work represents an important first step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity. This could lead to a broadband, high conversion efficiency low-cost solution to complement conventional PV devices.
A Solar Trough Concentrator for Pill-Box Flux Distribution Over a CPV Panel
Authors: Bader R. , Steinfeld A.
Published: January 2010

An integral methodology is formulated to analytically derive the exact profile of a solar trough concentrator that delivers a uniform radiative flux distribution over a flat rectangular target area at the focal plane. The Monte Carlo ray-tracing technique is applied to verify the analytical solution and investigate the effect of sun shape and mirror surface imperfections on the radiation uniformity and spillage. This design is pertinent to concentrating photovoltaics at moderate mean solar flux concentration ratios of up to 50 suns.
Sub-200nm gap electrodes by soft UV nanoimprint lithography using polydimethylsiloxane mold without external pressure
Authors: Hamouda F. , Barbillon G. , Gaucher F. , Bartenlian B.
Published: January 2010

In this article, the authors present an alternative approach to electron beam lithography allowing the fabrication of gap electrodes with dimensions less than 200nm. This approach consists of the soft ultraviolet nanoimprint lithography on nonstandard sample sizes, using polydimethylsiloxane (PDMS) as a flexible mold material. By simple deposit of the PDMS mold on the substrate, they succeeded in imprinting gaps in Amonil and the transfer of patterns of polymethylmethacrylate/Amonil bilayer was achieved by etching the substrate with a suitable reactive ion etching process. The imprint pressure was ensured by only the weight of the PDMS mold.
Making high-fidelity imprint template by resist patterns over a flexible conductive polymer substrate
Authors: Ye Xiangdong , Ding Yucheng , Duan Yugang , Liu Hongzhong , Shao Jinyou
Published: January 2010

A technique to fabricate an imprint template is proposed, based on a direct replication of the electronic-beam lithography resist patterns over a flexible conductive polymer substrate. This approach will simplify the template-making process because no anisotropic dry etching is required to transfer the resist pattern into a template material as usual. The flexible polymer film used as the substrate will be helpful during the detaching step of the template obtained; moreover, the flexibility of the substrate can be used to fabricate templates with curved-surface patterns. Using the technique, both the polymer templates and metal templates can be fabricated, and the above advantages will allow the templates to obtain the high-fidelity patterns directly from the electronic-beam lithography.
Asthma and airway hyperresponsiveness among Belgian conscripts, 1978-91.
Authors: Dubois P , Degrave E , Vandenplas O
Published: January 2010

BACKGROUND: Although there is convincing evidence that the prevalence of asthma among children has increased over the last three decades, it remains uncertain whether such an upward trend has occurred in adults. The aim of this study was to assess whether the prevalence of asthma has changed in young Belgian adults in recent years. METHODS: A retrospective analysis was conducted of available statistics from the Belgian Armed Forces for the period 1978-91 because conscripts who reported a history of past or current asthma at call-up examination underwent standardised assessment of non-specific airway responsiveness by military chest physicians. Exemption from military service due to asthma was strictly based on the objective evidence of airway hyperresponsiveness. RESULTS: A mean of 48,331 conscripts aged 17-31 years were examined annually from 1978 to 1991. The prevalence of reported asthma rose from 2.4% in 1978 to 7.2% in 1991, while the proportion of asthmatics with airway hyperresponsiveness remained little changed at 48.4% in 1978 and 51.4% in 1991. CONCLUSIONS: The observed increase in prevalence of reported asthma was not accompanied by a decrease in the proportion of conscripts with objectively measured airway hyperresponsiveness. These observations provide supporting evidence that the increase in asthma symptoms was not simply due to reporting bias.
Radiofrequency resection of bronchial tumours in combination with cryotherapy: evaluation of a new technique.
Authors: Marasso A , Bernardi V , Gai R , Gallo E , Massaglia G M , Onoscuri M , Cardaci S B
Published: January 2010

BACKGROUND: A number of treatments, including Nd-YAG laser therapy, brachytherapy, cryotherapy, electrocautery, and photodynamic therapy, can re-open the obstructed bronchial lumen in patients with inoperable obstructive bronchial tumours. None of these is considered to be a "gold standard". METHODS: The results of a retrospective study of 98 patients treated by radiofrequency tissue ablation and subsequent cryotherapy between January 1994 and June 1995 are reported. The patients were divided in two groups according to whether they were treated either after (group 1, n = 50) or before (group 2, n = 48) radiotherapy and/or chemotherapy. Bronchoscopic follow up was performed. The intervention was considered successful if the lumen was opened by > 80% and partially successful if it was opened by > 50%. RESULTS: In group 1 treatment was successful in 60%, partially successful in 32%, and unsuccessful in 8%. The median survival time was five months from the time of bronchoscopic surgery. In group 2 treatment was successful in 66%, partially successful in 21.5%, and unsuccessful in 12.5%, with a median survival time of 14 months from the time of bronchoscopic treatment. Forty patients (24 in group 1 and 16 in group 2) received a Dumon stent. CONCLUSIONS: Radiofrequency bronchoscopic surgery with cryotherapy appears to be a useful technique in the treatment of tracheobronchial obstruction.
Effect of an inhaled glucocorticosteroid on mast cell and smooth muscle beta 2 adrenergic tolerance in mild asthma.
Authors: Yates D H , Worsdell M , Barnes P J
Published: January 2010

BACKGROUND: Regular inhaled beta 2 agonist therapy is associated with loss of bronchoprotection to indirect bronchial provocation challenges such as allergen or adenosine monophosphate (AMP), while directly acting challenge is less affected, implying preferential mast cell tolerance. Glucocorticosteroids may reverse such beta 2 adrenoreceptor tolerance and upregulate mast cell beta 2 adrenoceptor function. METHODS: The effect of single high dose glucocorticosteroids on terbutaline induced loss of bronchoprotection was studied in a placebo controlled, double blind, cross-over study. Fifteen asthmatic subjects who were not taking inhaled glucocorticosteroids underwent two 10-day treatment periods with terbutaline (500 micrograms four times daily via Turbohaler), each followed by a single dose of inhaled budesonide (800 micrograms via Turbohaler) or identical placebo. RESULTS: Regular treatment with terbutaline resulted in significant loss of bronchoprotection to AMP (mean difference (95% CI) -1.7 (-3.0 to 0.4) doubling dilutions) but not to methacholine (mean difference -0.1 (-1.0 to 0.8) doubling dilutions). Single high dose budesonide increased the protective effect of terbutaline more to AMP than to methacholine challenge (+0.76 (0.3) doubling dilutions compared with +0.13 (0.4) doubling dilutions, respectively). The mean (SE) difference between budesonide and placebo for methacholine challenge was 0.08 (0.14) whereas that for AMP was 0.075 (0.15); p = NS. The difference in PC20 was not statistically significant when compared with placebo for either challenge agent. CONCLUSIONS: Inhaled glucocorticosteroids in a single dose had no significant effect in restoring terbutaline induced loss of bronchoprotection, implying that mast cell beta 2 adrenoceptor sensitivity is not restored by a single dose of an inhaled glucocorticosteroid in asthma.
Secretory leukoprotease inhibitor: a native antimicrobial protein presenting a new therapeutic option?
Authors: Tomee J F , Koëter G H , Hiemstra P S , Kauffman H F
Published: January 2010

Secretory leukoprotease inhibitor (SLPI) is a low molecular weight serine protease inhibitor found on various mucosal surfaces and has been ascribed an important role in maintaining the protease-anti-protease balance of the airways. Recent scientific evidence has suggested that SLPI may also have a broad spectrum antibiotic activity that includes antiretroviral, bactericidal, and antifungal activity. Given the unpropitious development of drug resistance to infectious micro-organisms in the human population, the need for therapeutic alternatives in the treatment of infectious diseases has become clear. SLPI may prove valuable in the prophylaxis and future treatment of infectious diseases, yet the clinical efficacy of SLPI remains largely to be elucidated.
Familial primary spontaneous pneumothorax consistent with true autosomal dominant inheritance.
Authors: Morrison P J , Lowry R C , Nevin N C
Published: January 2010

A family exhibiting spontaneous pneumothorax in a father and three offspring (two sons, and one daughter) is described. The mode of inheritance is apparently autosomal dominant with two episodes of male to male transmission in one family. The age of onset varied by up to 13 years within the family. Isolated autosomal dominant pneumothorax appears to be a distinct clinical entity.
Changes in sputum composition between two inductions performed on consecutive days.
Authors: Holz O , Richter K , Jörres R A , Speckin P , Mücke M , Magnussen H
Published: January 2010

BACKGROUND: Sputnum induction is a non-invasive method for obtaining cellular and biochemical material from the airways and appears to be particularly suited for repeated testing. However, it has not been clarified whether repeated inductions lead to a change in sputum composition. The aim of this study was to compare induced sputum results between two inductions performed 24 hours apart. METHODS: Ten subjects with mild asthma and 19 healthy subjects were included. Sputum was obtained during three consecutive 10 minute periods of hypertonic saline inhalation. Samples were analysed separately for the three inhalation periods. Corresponding pooled values were computed, taking into account total cell numbers of each inhalation period. RESULTS: In the three consecutive inhalation periods mean (SE) percentages of neutrophils increased from 29.2 (4.2)%, 22.0 (4.6)% and 14.5 (2.9)% on day 1 to 43.1 (5.3)%, 34.8 (5.5)% and 25.7 (5.3)% on day 2 in healthy subjects and from 21.3 (4.3)%, 24.1 (5.9)% and 15.9 (3.7)% to 35.9 (6.9)%, 30.7 (7.1)% and 31.8 (6.5)% in asthmatic subjects. This parallel shift corresponded to a mean (95% CI) increase in the pooled percentages of neutrophils of 17.4 (11.6) to 23.3)% in healthy and 14.6 (1.2 to 28.0)% in asthmatic subjects. In contrast to neutrophils, the percentage of macrophages decreased from day 1 to day 2, while eosinophil and lymphocyte percentages did not change significantly. CONCLUSION: These results suggest that the induction procedure itself causes a change in the composition of sputum detectable after 24 hours. This effect has to be taken into account when repeated sputum induction is performed.
Modulational stability of solitary states in a lossy nonlinear electrical line
Authors: Kengne E. , Vaillancourt R.
Published: January 2010

The modified Ginzburg–Landau equation that describes the pulse propagation in a lossy electrical transmission line is used to derive an eigenvalue problem that allows a detailed investigation of the modulational stability of the solitary states in the line. It is found that the growth rates of the perturbation are complex functions of the spatial variable and that, in general, the solitary states in the network can be either modulationally stable, unstable, or destabilized under a given perturbation function.
Effect of temperature on the binding energy of a shallow hydrogenic impurity in a quantum well wire
Authors: Emam T. G.
Published: January 2010

In this work, we investigate the variation of the binding energy of an on-axis hydrogenic impurity in a cylindrical semiconductor GaAsalxGa1–xAs quantum well wire (QWW) with temperature, by taking into account the temperature dependance of the electron masses and dielectric constants in the quantum well and potential barrier region as well as the temperature dependence of the barrier height. This investigation is important in understanding the role such impurities can play in determining the transport properties of such systems. The results show enhancement of the binding energy as the temperature is decreased, specially for small values of wire radius.
Exact inflationary solution in the chaotic inflation model to non-minimally coupled scalar field
Authors: Chen Shiwu , Hao Xizhun , Liu Xiongwei , Yang Shuzheng
Published: January 2010

We present a new exact inflationary solution for the chaotic inflation model with non-minimal coupling, by taking the Hubble parameter directly as a function of a scalar field. We then prove that the spectral index of the scalar density fluctuation (and other parameters), which derived from the exact inflationary solution, is exactly consistent with recent astronomical observations.
( q q ¯ ) -pion mass and decay constant in a relativistic independent-quark model
Authors: Jena S. N. , Muni M. K. , Pattnaik H. R.
Published: January 2010

The mass and decay constant of the [Formula: see text]-pion together with the masses of ρ and ω mesons are calculated in a chiral symmetric potential model of independent quarks, taking into account the corrections due to the possible residual interactions, such as quark–pion coupling arising out of the requirement of chiral symmetry and quark gluon coupling arising out of one-gluon-exchange, and that due to the spurious center-of-mass motion of the meson core. The effective potential representing phenomenologically the nonperturbative gluon interactions, including gluon self coupling, is chosen with equally mixed scalar and vector parts in a logarithmic form. The result obtained for the physical mass of [Formula: see text]-pion is consistent with that of the PCAC-pion, and the pion-decay constant reasonably agrees with experiment.
Effect of magnetic field on the screening due to hot electrons in the presence of shallow attractive traps
Authors: Midday S. , Bhattacharya D. P.
Published: January 2010

The electrostatic screening of the perturbation potential due to lattice imperfections has been investigated here in the presence of crossed electric and non-quantizing magnetic fields, under conditions where the lifetime of the carriers of the non-equilibrium ensemble in a semiconductor is controlled by shallow attractive traps. The screening characteristics are obtained in the general case of any mechanism of energy and momentum scattering of the hot carriers in the strong and weak magnetic field limits. For some definite scattering mechanisms, however, the characteristics are calculated in the presence of any finite value of the magnetic field. The results show interesting characteristic features that are quite different from what one can obtain for an ensemble of carriers that is in thermodynamic equilibrium with the lattice atoms. It has been observed that, depending upon the prevalent conditions with respect to the dominant momentum and energy relaxation processes and the strength of the applied electric field, the presence of the magnetic field sometimes brings in significant changes in both the qualitative and the quantitative aspects of the field dependence of the screening length. Apart from that, the screening length now shows a rather complex and altogether different dependence upon the lattice temperature. The numerical results featuring the interesting characteristics under different prevalent conditions are presented for Ge. It has been explained in what novel way the present problem describes the dependence of the screening length due to an ensemble of hot electrons on the external electric and magnetic fields. The limitations of the present theory, as well as its possible applicability for the characterization of semiconductors under high field conditions at low lattice temperatures, are discussed.
Line-source diffraction by a slit in a moving fluid
Authors: Ayub M. , Naeem A. , Nawaz R.
Published: January 2010

The diffraction of a cylindrical acoustic wave from a slit in a moving fluid using Myers condition (J. Sound Vib. 71, 429 (1980)) is investigated, and an improved form of the analytical solution for the diffracted field is presented. The problem is solved analytically using an integral transform, Wiener–Hopf technique, and the modified method of stationary phase. The mathematical results are well supported by graphical discussion showing how the absorbing parameter and Mach number affect the amplitude of the velocity potential.
PUT OPTION PRICES AS JOINT DISTRIBUTION FUNCTIONS IN STRIKE AND MATURITY: THE BLACK–SCHOLES CASE
Authors: MADAN D. , ROYNETTE B. , YOR M.
Published: January 2010

For a large class of ℝ+ valued, continuous local martingales (Mtt ≥ 0), with M0 = 1 and M∞ = 0, the put quantity: ΠM (K,t) = E ((K - Mt)+) turns out to be the distribution function in both variables K and t, for K ≤ 1 and t ≥ 0, of a probability γM on [0,1] × [0, ∞[. In this paper, the first in a series of three, we discuss in detail the case where [Formula: see text], for (Bt, t ≥ 0) a standard Brownian motion.
DOES CURVATURE ENHANCE FORECASTING?
Authors: ALMEIDA CAIO , GOMES ROMEU , LEITE ANDRÉ , SIMONSEN AXEL , VICENTE JOSÉ
Published: January 2010

In this paper, we analyze the importance of curvature term structure movements on forecasts of interest rates. An extension of the exponential three-factor Diebold and Li (2006) model is proposed, where a fourth factor captures a second type of curvature. The new factor increases model ability to generate volatility and to capture nonlinearities in the yield curve, leading to a significant improvement of forecasting ability. The model is tested against the original Diebold and Li model and some other benchmarks. Based on a forecasting experiment with Brazilian fixed income data, it obtains significantly lower bias and root mean square errors for most examined maturities, and under three different forecasting horizons. Robustness tests based on two sub-sample analyses partially confirm the favorable results.
A NOVEL REDUCTION OF THE SIMPLE ASIAN OPTION AND LIE-GROUP INVARIANT SOLUTIONS
Authors: TAYLOR STEPHEN , GLASGOW SCOTT
Published: January 2010

We develop the complete 6-dimensional classical symmetry group of the partial differential equation (PDE) that governs the fair price of a simple Asian option within a simple market model. The symmetries we expose include the 5-dimensional symmetry group partially noted by Rogers and Shi, and communicated implicitly by the change of numéraire arguments of Večeř (in which symmetries reduce the original 2 + 1 dimensional simple Asian option PDE to a 1 + 1 dimensional PDE). Going beyond this previous work, we expose a new 1-dimensional space of symmetries of the Asian PDE that cannot reasonably be found by inspection. We demonstrate that the new symmetry could be used to formulate a new, "nonlinear" derivative security that has a 1 + 1 dimensional PDE formulation. We indicate that this nonlinear security has a closed-form pricing formula similar to that of the Black–Scholes equation for a particular market dependent payoff, and show that hedging the short position in this particular exotic option is stable for all market parameters. We also demonstrate the patently Lie-algebraic method for obtaining the already well-known "Rogers–Shi–Večeř" reduction.
A BARGAINING MODEL FOR FINITE N-PERSON MULTI-CRITERIA GAMES
Authors: MONROY LUISA , MÁRMOL AMPARO M. , RUBIALES VICTORIANA
Published: January 2010

In this paper a multi-criteria game model, which allows interactions between players, is studied. The problem addressed is considered as a cooperative game in order to achieve consensus solutions which are evaluated with respect to several criteria simultaneously. The main idea consists of analyzing finite multi-criteria n-person games as multi-criteria bargaining games. The notion of Pareto-optimal guaranteed payoffs as a generalization of the maximin values of scalar games is proposed, together with a solution concept which can be characterized as the solutions of multi-criteria linear programming problems. A procedure to incorporate additional information about the players' preferences in order to reach a final consensus is also provided.
A GAME OF SETTLEMENTS IN PUBLIC CONTRACTS
Authors: PAUWELS WILFRIED , KORT PETER M.
Published: January 2010

The paper considers a public authority wishing to carry out a major public project. As a result of competitive bidding the project is assigned to the firm with the lowest bid. The cost of the project is uncertain in the sense that it can be low or high. After the bidding process the firm observes the true cost, while the government remains uninformed. After learning about the true cost, the firm can start to renegotiate the contract by proposing an increase of the price. Such an increase is only justified in case costs are high. If the government rejects the new price proposal, a law suit follows.

This situation is modeled as a signaling game. If the prior probability of the costs being low is low (high), a pooling (separating) equilibrium occurs. In the pooling equilibrium the government always accepts the firm's proposal. In the separating equilibrium the government can apply a mixed strategy when costs are high. Then it goes to court with a certain probability. Compared to a pure strategy, the mixed strategy has the advantage that legal costs are lower.

In our economic analysis we compare the American and the English rule for sharing the litigation expenses. A main result is that under the American rule the legal expenses are lower and welfare is higher in the mixed strategy equilibrium. We also study the importance of the firm's commitment to its new price proposal.
A NOTE ON THE CARRERAS-COLEMAN DECISIVENESS INDEX
Authors: BARUA RANA , CHAKRAVARTY SATYA R. , ROY SONALI
Published: January 2010

In this paper we establish equivalence between six collections of axioms that all characterize the Carreras-Coleman decisiveness index. Axioms in each of the different sets are shown to be independent.
A LARGE POPULATION, GAME THEORETIC MODEL OF JOB-SEARCH WITH DISCOUNTING
Authors: RAMSEY DAVID M.
Published: January 2010

This paper considers a large population, game theoretic job-search problem, in which the ratio of job searchers to jobs is α. There are n distinct types of jobs, each with an associated value. Each searcher can only accept one job and cannot recall a job previously rejected. Once a searcher accepts a job, no other searcher can obtain that particular job. The reward to a searcher is taken to be the value of the job he/she obtains discounted by a factor of e-γt, where t is the time spent searching and γ > 0. It is shown that a unique evolutionarily stable strategy (ESS) exists for such problems. Two iterative algorithms for approximating the ESS are considered. In the case where there are only two types of job, the ESS can be calculated directly.
MULTI RESOLUTION BASED IMAGE REGISTRATION TECHNIQUE FOR MATCHING DENTAL X-RAYS
Authors: RAMPRASAD P. , NAGARAJ H. C. , PARASURAM M. K. , SHUBHA M.
Published: January 2010

This paper presents a new technique to assess the bone formation after periapical dental surgery. The proposed technique consists of two main stages: image registration and spectral subtraction stages. Image registration is used to avoid projection errors produced due to nonstandardization of X-ray scanners. Wavelet coefficients are used instead of grey values for registering the images. Coarse to fine strategy with four levels of resolutions is used to speed up the process. The second stage is the spectral subtraction stage. It is used to yield the difference image between pre- and post-operative images which represents the bone gain or bone loss with light and dark areas, respectively. Algorithm has been applied on a number of pre- and post-surgery intra oral periapical (IOP) dental X-ray images. Mean and root mean square error (RMSE) are computed to assess the quality of registration technique. The technique presented here is compared with grey level based method; results show that proposed technique outperforms conventional grey level method based on dyadic sampling.
DECISION SUPPORT SYSTEM BASED ON DCT TEXTURE FEATURES FOR DIAGNOSIS OF ESOPHAGITIS
Authors: SARAF SANTOSH S. , UDUPI G. R. , HAJARE SANTOSH D.
Published: January 2010

Esophagitis is essentially inflammation of the esophageal squamous mucosa. One of the major reasons for cause of Esophagitis is the acid reflux from the stomach. This condition is observed in the process of upper gastro-intestinal tract endoscopy and the diagnosis is arrived at by examining the images of the esophagus. The diagnosis is based on the observation of the lesions and coloration of the digestive mucosa. Our paper reports an implementation of Decision Support System (DSS) for diagnosis of Esophagitis based on the analysis of color and texture features of the images captured during the process of endoscopy. The Hue Saturation and Intensity color model is adapted. The statistical features of the Hue and Saturation form the color features and the texture features are determined by Discrete Cosine Transform coefficients of the image. The decision making structure is a feed forward neural network. The DSS has been tested and results are reported.
AUTOMATIC COMPUTER-BASED TRACINGS (ACT) IN LONGITUDINAL 2-D ULTRASOUND IMAGES USING DIFFERENT SCANNERS
Authors: MOLINARI FILIPPO , LIBONI WILLIAM , GIUSTETTO PIERANGELA , BADALAMENTI SERGIO , SURI JASJIT S.
Published: January 2010

Objective. The aim of this paper is to show an algorithm for the automatic computer-based tracing (ACT) of common carotid artery (CCA) in longitudinal B-mode ultrasound images characterized by four main features: (i) user-independence; (ii) suitability to normal and pathological images; (iii) robustness to noise; and (iv) independent of ultrasound OEM scanner.

Methods. Three hundred longitudinal B-mode images (100 normal CCAs, 100 CCAs with increased intima-media thickness, 60 stable plaques, and 40 echolucent plaques) were acquired using three different (GE, Siemens, and Biosound) OEM ultrasound image scanners. The algorithm processed each image to delineate the region of interest containing the CCA. Output of the algorithm are three segmentation lines representing (a) distal (far) and (b) near adventitia layers, and (c) lumen of the CCA. Three operators qualitatively scored the ACTs.

Results. The CCA was correctly automatically traced in all the 300 B-mode images. The performance was independent on the image scanner used to acquire the image or on the type of the CCA (healthy versus pathologic). Eight ACTs out of 300 received a poor score after visual inspection due to an automated adventitia tracing that did not correctly follow the CCA wall in a small portion of the image.

Conclusions. The proposed algorithm is robust in ACTs of CCA since it is independent of scanner and normal/abnormal wall. This approach could constitute a general basis for a completely automated segmentation procedure.
CARDIAC CONTRACTILITY MEASURES OF LEFT VENTRICULAR SYSTOLIC FUNCTIONAL ASSESSMENT OF NORMAL AND DISEASED HEARTS
Authors: GHISTA DHANJOO N. , ZHONG LIANG , LE THU-THAO , TAN RU-SAN
Published: January 2010

Left ventricular (LV) contraction is the basis of LV systolic function, impairment of which underlies heart failure pathophysiology. Its accurate quantification in the form of LV contractility indices is imperative for diagnostic and follow-up assessment of LV systolic function in heart failure.

Herein, we analyze LV contractile performance by focusing on LV contractility indices at different physiological organizational levels: from sarcomere dynamics to LV myocardial properties (such as elastic modulus and elastance), and from LV wall contractile stress development to the generation of intra-LV blood flow velocities and pressure distributions. Further, we present the development analyses of these indices and their medical applications. Using improved development of invasive and noninvasive techniques for measuring ventricular pressure, geometry, and volume, we show how these indices have become more amenable for clinical usage to obtain better patient assessment.

The purpose of this paper is to present a comprehensive coverage of LV contraction physiology, indices to qualify LV contraction, formulation, and medical applications of some major intrinsic LV contractility indices, so as to provide the basis of functional assessment of normal versus diseased hearts.
COMPUTER-BASED IDENTIFICATION OF CATARACT AND CATARACT SURGERY EFFICACY USING OPTICAL IMAGES
Authors: NAYAK JAGADISH , BHAT P. SUBBANNA , ACHARYA U. RAJENDRA , FAUST OLIVER , MIN LIM CHOO
Published: January 2010

The eyes are complex sensory organs, they are designed to capture images under varying light conditions. Eye disorders, such as cataract, among the elderly are a major health problem. Cataract is a painless clouding of the eye lens which develops over a long period of time. During this time, the eyesight gradually worsens. It can eventually lead to blindness and, is common in older people. In fact, about a third of people over 65 have cataracts in one or both eyes.

In this paper, we made use of two types of classifiers for identification of normal, cataract (early and developed stage), and post-cataract eyes using features extracted from optical images. These classifiers are artificial neural network and support vector machine. A database of 174 subjects, using the cross-validation strategy, is used to test the effectiveness of both classifiers. We demonstrate a sensitivity of more than 90% for both of these classifiers. Furthermore, they have a specificity of 100% and, as such, the results obtained are very promising. The proposed feature extraction and classification systems are ready clinically to run on a large amount of data sets.
APPLICATION OF SOLID ELEMENT IN IRONING SIMULATION AND OPTIMIZATION OF PROCESS PARAMETERS
Authors: XU JIANGPING , DU TING , LIU YUQI , ZHANG ZHIBING
Published: January 2010

Based on viscous damping hourglass control method, a one-point integrated hexahedral finite element dynamic explicit algorithm is programmed and ironing process simulation has also been carried out. Simulation results with controlled hourglass algorithm shows that the hourglass control method is robust in this research and the setting of hourglass coefficient is analyzed. Furthermore, the reduction ratio R, friction coefficient μ between molds and blank, semi-angle α, which affect the maximum forming force, are discussed in detail. Simulation results show that the proper choice of those process parameters could obtain minimum maximum load force, thus effectively decrease moulds wear and lengthen moulds life.
VARIATIONAL ITERATION METHOD FOR SOLVING NONLINEAR HIGHER-ORDER INITIAL AND BOUNDARY VALUE PROBLEMS
Authors: MOHYUD-DIN SYED TAUSEEF , NOOR MUHAMMAD ASLAM , NOOR KHALIDA INAYAT
Published: January 2010

In this paper, we apply variational iteration method (VIM) and variational iteration method using Adomian's polynomials for solving nonlinear boundary value problems. The proposed iterative scheme finds the solution without any discretization, linearization, perturbation, or restrictive assumptions. Several examples are given to verify the accuracy and efficiency of the method. We have also considered an example where the proposed VIM is not reliable.
A HYPERBOLIC SHEAR DEFORMATION THEORY FOR FLEXURE AND VIBRATION OF THICK ISOTROPIC BEAMS
Authors: GHUGAL YUWARAJ MAROTRAO , SHARMA RAJNEESH
Published: January 2010

A Hyperbolic Shear Deformation Theory taking into account transverse shear deformation effects, is presented for the static flexure and free flexural vibration analysis of thick isotropic beams. The displacement field of the theory contains two variables and does not require shear correction factor. The hyperbolic sine function is used in the displacement field in terms of thickness coordinate to represent shear deformation. The most important feature of the theory is that the transverse shear stress can be obtained directly from the use of constitutive relation, satisfying the stress free boundary conditions at top and bottom of the beam. Hence, the theory obviates the need of shear correction factor. Governing differential equations and boundary conditions of the theory are obtained using the principle of virtual work. Results obtained for flexure and free vibration of simply supported uniform, isotropic beams are compared with those of elementary, refined, and exact beam theories to validate the accuracy of the theory.
THE TRI-PENTAGONAL NUMBER THEOREM AND RELATED IDENTITIES
Authors: BERKOVICH ALEXANDER
Published: January 2010

I revisit an automated proof of Andrews' pentagonal number theorem found by Riese. I uncover a simple polynomial identity hidden behind his proof. I explain how to use this identity to prove Andrews' result along with a variety of new formulas of similar type. I reveal an interesting relation between the tri-pentagonal theorem and items (19), (20), (94), (98) on the celebrated Slater list. Finally, I establish a new infinite family of multiple series identities.
ON THE SCHRÖTER FORMULA FOR THETA FUNCTIONS
Authors: LIU ZHI-GUO , YANG XIAO-MEI
Published: January 2010

The Schröter formula is an important theta function identity. In this paper, we will point out that some well-known addition formulas for theta functions are special cases of the Schröter formula. We further show that the Hirschhorn septuple product identity can also be derived from this formula. In addition, this formula allows us to derive four remarkable theta functions identities, two of them are extensions of two well-known Ramanujan's identities related to the modular equations of degree 5. A trigonometric identity is also proved.