bluuebunny/crossref_metadata_2025 huggingface dataset:
Film-Cooling Flowfields With Trenched Holes on an Endwall
Authors: Sundaram N. , Thole K. A.
Published: July 2009

The leading edge region along the endwall of a stator vane experiences high heat transfer rates resulting from the formation of horseshoe vortices. Typical gas turbine endwall designs include a leakage slot at the combustor-turbine interface as well as film-cooling holes. Past studies have documented the formation of a horseshoe vortex at the leading edge of a vane, but few studies have documented the flowfield in the presence of an interface slot and film-cooling jets. In this paper, a series of flowfield measurements is evaluated at the leading edge with configurations including a baseline with neither film-cooling holes nor an upstream slot, a row of film-cooling holes and an interface slot, and a row of film-cooling holes in a trench and an interface slot. The results indicated the formation of a second vortex present for the case with film-cooling holes and a slot relative to the baseline study. In addition, turbulence intensity levels as high as 50% were measured at the leading edge with film-cooling holes and a slot compared with the 30% measured for the baseline study. A trench was shown to provide improved overall cooling relative to the no trench configuration as more of the coolant stayed attached to the endwall surface with the trench.
Turbine Blade Platform Film Cooling With Typical Stator-Rotor Purge Flow and Discrete-Hole Film Cooling
Authors: Gao Zhihong , Narzary Diganta , Han Je-Chin
Published: July 2009

This paper is focused on the effect of film-hole configurations on platform film cooling. The platform is cooled by purge flow from a simulated stator-rotor seal combined with discrete-hole film cooling within the blade passage. The cylindrical holes and laidback fan-shaped holes are assessed in terms of film-cooling effectiveness and total pressure loss. Lined up with the freestream streamwise direction, the film holes are arranged on the platform with two different layouts. In one layout, the film-cooling holes are divided into two rows and more concentrated on the pressure side of the passage. In the other layout, the film-cooling holes are divided into four rows and loosely distributed on the platform. Four film-cooling hole configurations are investigated totally. Testing was done in a five-blade cascade with medium high Mach number condition (0.27 and 0.44 at the inlet and the exit, respectively). The detailed film-cooling effectiveness distributions on the platform were obtained using pressure sensitive paint technique. Results show that the combined cooling scheme (slot purge flow cooling combined with discrete-hole film cooling) is able to provide full film coverage on the platform. The shaped holes present higher film-cooling effectiveness and wider film coverage than the cylindrical holes, particularly at higher blowing ratios. The hole layout affects the local film-cooling effectiveness. The shaped holes also show the advantage over the cylindrical holes with lower total pressure loss.
Aerothermal Performance of Streamwise and Compound Angled Pulsating Film Cooling Jets
Authors: Aga Vipluv , Mansour Michel , Abhari Reza S.
Published: July 2009

The quantification of aerothermal loss is carried out for streamwise and compound angled film cooling jets with and without large scale pulsation. This paper reports on the simultaneous measurements of the unsteady pressure and temperature field of streamwise and a 60 deg compound angled film cooling jet, both with a 30 deg surface angle over a flat plate with no pressure gradients. Turbine representative nondimensionals in terms of the geometry and operating conditions are studied. The main flow is heated more than the injected flow to have a temperature difference and hence a density ratio of 1.3, while the blowing ratio is maintained at 2. The entropy change, derived from pressure and temperature measurements, is calculated by using modified reference conditions to better reflect the losses in both the jet and the freestream. The effects of the periodic unsteadiness associated with rotating machinery are simulated by pulsating the jets. These effects are documented through time-resolved entropy change contours. Mass-averaged entropy and kinetic energy loss coefficients seem to be apt quantities for comparing the aerothermal performance of streamwise and compound angled injections. It is observed that the mass-averaged entropy loss of a streamwise jet doubles when it is pulsated, whereas that of a compound angled jet increases by around 50%. It may be conjectured from the measurements shown in this study that streamwise oriented jets suffer most of their entropy losses at the hole exit due to separation, whereas in compound angled jets, downstream thermal mixing between the jet and the freestream is the dominant mechanism.
Windage Power Losses From Spiral Bevel Gears With Varying Oil Flows and Shroud Configurations
Authors: Johnson Graham , Chandra Budi , Foord Colin , Simmons Kathy
Published: July 2009

In many aero-engines, the power to drive accessories is transmitted through high speed bevel gears in a chamber in the center of the engine. The windage power loss (WPL) associated with these gears makes a significant contribution to the overall heat generation within the chamber. Shrouding the gears provides an effective method of reducing this WPL and managing the flow of lubricating oil. Experimental and computational programs at the University of Nottingham Technology Centre in Gas Turbine Transmission Systems are providing an improved understanding of shroud performance and design. This paper presents the results from a pair of shrouded meshing gears run at representative speeds and oil flow in a rig with speed and torque measurement. A previously published study of a single bevel gear operating in air (Johnson et al., 2007, “Experimental Investigation Into Windage Power Loss From a Shrouded Spiral Bevel Gear” ASME Paper No. GT2007-27885) found a reduction in torque of up to 70% from shrouding. In this work, the addition of oil and the pinion gear did not lead to high torque due to the buildup of oil under the shrouds, but the reduction in torque due to fitting the shrouds is significantly less than was found for the same gear in air alone. In order to isolate the various parameters, further testing with a single gear was carried out. A fully (360 deg) shrouded gear shows a big improvement over an unshrouded gear when running in air alone, but much of this benefit disappears as soon as a very small amount of oil is introduced under the shroud. This implies that the oil is recirculating under the shroud. Increasing the oil flow beyond this initial level increases the torque by the amount required to accelerate the oil mass flow up to the peripheral speed of the gear. Providing a full width slot in the shroud downstream of the oil jet allows the oil to escape without any recirculation and restores much of the benefit of the shroud. Further insight into the oil behavior is obtained from torque measurements and observations through a transparent shroud and with various slot configurations. Video observation shows evidence of a vortex flow under the shroud that carries some of the oil toward the inner diameter of the gear. The three main windage contributors, air alone, recirculation of oil under the shroud, and acceleration of the feed oil, are quantified and methods for achieving the optimum design are discussed.
Simplified Approach to Predicting Rough Surface Transition
Authors: Boyle R. J. , Stripf M.
Published: July 2009

Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consistent with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparisons are presented with published experimental data. Some of the data are for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach taken in this analysis is to treat the roughness in a statistical sense, consistent with what would be obtained from blades measured after exposure to actual engine environments. An approach is given to determine the equivalent sand grain roughness from the statistics of the regular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test conditions. Additional comparisons are made with experimental heat transfer data, where the roughness geometries are both regular and statistical. Using the developed analysis, heat transfer calculations are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.
The Effect of Leading-Edge Geometry on Wake Interactions in Compressors
Authors: Wheeler Andrew P. S. , Sofia Alessandro , Miller Robert J.
Published: July 2009

The effect of leading-edge geometry on the wake/boundary-layer interaction was studied in a low-speed single-stage HP compressor. Both a 3:1 elliptic and a circular leading edge were tested on a controlled diffusion aerofoil stator blade. Experiments were undertaken on the stator suction surface; these included hotwire boundary-layer traverses, surface hotfilm measurements, and high resolution leading-edge pressure measurements. Steady computational fluid dynamics (CFD) predictions were also performed to aid the interpretation of the results. The two leading-edge shapes gave rise to significantly different flows. For a blade with an elliptic leading edge (Blade A), the leading-edge boundary layer remained attached and laminar in the absence of wakes. The wake presence led to the formation of a thickened laminar boundary layer in which turbulent disturbances were observed to form. Measurements of the trailing-edge boundary layer indicated that the wake/leading-edge interaction for Blade A raised the suction-surface loss by 20%. For a blade with a circular leading edge (Blade B), the leading-edge boundary-layer exhibited a separation bubble, which was observed to reattach laminar in the absence of wakes. The presence of the wake moved the separation position forward while inducing a turbulent reattachment upstream of the leading-edge time-average reattachment position. This produced a region of very high momentum thickness at the leading edge. The suction-surface loss was found to be 38% higher for Blade B than for Blade A. Wake traverses downstream of the blades were used to determine the total profile loss of each blade. The profile loss of Blade B was measured to be 32% higher than that of Blade A.
Comment on “Can Maxwell’s equations be obtained from the continuity equation?” by J. A. Heras [Am. J. Phys. 75, 652–657 (2007)]
Authors: Kapuscik Edward
Published: July 2009

Heras’ derivation of Maxwell’s equations from the continuity equation is criticized.
Experimental special relativity with a meter stick and a clock
Authors: Lund M. , Uggerhøj U. I.
Published: July 2009

We present measurements of the velocity of electrons, performed with an apparatus using the time-of-flight method, to demonstrate that the speed of light c is the limiting speed for electrons. The results obtained show the applicability of relativity in a regime where nonrelativistic physics predicts velocities exceeding c. The main advantages of the apparatus are the simplicity of its operation and the data analysis. By using electrons from weak radioactive sources the experiment is suitable for the undergraduate laboratory. Furthermore, we show that with electrons from a linear accelerator and the same apparatus, excellent agreement between data and the relativistic expression for the speed of electrons in the keV-MeV energy range is observed.
Construction of a simple spherical air bearing
Authors: Masters M. F. , Reynolds C. , Suedhoff H. , DeArmond F. M.
Published: July 2009

A simple method requiring minimal tools and mechanical ability, is presented for making a spherical air bearing. The air bearings are used for an exploration of precession. Results of test measurements are presented.
The Planck mass and the Chandrasekhar limit
Authors: Garfinkle David
Published: July 2009

The Planck mass is often assumed to play a role only at the extremely high energy scales where quantum gravity becomes important. However, this mass plays a role in any physical system that involves gravity, quantum mechanics, and relativity. We examine the role of the Planck mass in determining the maximum mass of white dwarf stars.
First- and second-order Poisson spots
Authors: Kelly William R. , Shirley Eric L. , Migdall Alan L. , Polyakov Sergey V. , Hendrix Kurt
Published: July 2009

Although Thomas Young is generally given credit for being the first to provide evidence against Newton’s corpuscular theory of light, it was Augustin Fresnel who first stated the modern theory of diffraction. We review the history surrounding Fresnel’s 1818 paper and the role of the Poisson spot in the associated controversy. We next discuss the boundary-diffraction-wave approach to calculating diffraction effects and show how it can reduce the complexity of calculating diffraction patterns. We briefly discuss a generalization of this approach that reduces the dimensionality of integrals needed to calculate the complete diffraction pattern of any order diffraction effect. We repeat earlier demonstrations of the conventional Poisson spot and discuss an experimental setup for demonstrating an analogous phenomenon that we call a “second-order Poisson spot.” Several features of the diffraction pattern can be explained simply by considering the path lengths of singly and doubly bent paths and distinguishing between first- and second-order diffraction effects related to such paths, respectively.
Spectroscopy applied to observations of terrestrial light sources of uncertain origin
Authors: Stephan Karl D. , Ghimire Sagar , Stapleton William A. , Bunnell James
Published: July 2009

Sensitive spectroscopic instrumentation is now sufficiently portable to be used in field experiments involving terrestrial light sources as well as for astronomical observations. We report the results of a 20 night investigation of a phenomenon known as “Marfa lights” with the aid of a Schmidt-Cassegrain telescope and a CCD-array spectrometer. We show that the combination of computer azimuth and altitude logging, video recording, and continuous spectroscopy provides enough data for unequivocal identification of false positives such as distant streetlamps, automotive headlamps, and fires. We demonstrate that spectroscopic analysis of atmospheric molecular oxygen absorption can be used to determine distances of continuum-spectrum sources with an accuracy of 6% or better for distances of 4 km or greater. We also used astronomical objects for both directional references and approximate estimation of the system noise level in terms of minimum usable light flux.
Optical tweezers for undergraduates: Theoretical analysis and experiments
Authors: Rocha M. S.
Published: July 2009

A theoretical treatment of optical tweezers is presented at a level suitable for undergraduates. We explore the Rayleigh and the geometrical optics regimes with an emphasis on the latter. We discuss a model for the geometrical optics regime, including spherical aberration effects, and show that the model can easily be implemented numerically. A comparison of the model with experimental data yields excellent agreement between theory and experiment. We also briefly discuss a theory of optical tweezers valid for microspheres of any size.
What course elements correlate with improvement on tests in introductory Newtonian mechanics?
Authors: Morote Elsa-Sofia , Pritchard David E.
Published: July 2009

In an MIT calculus-based introductory Newtonian mechanics course, we study the effectiveness of various instructional course elements: electronic and written homeworks, collaborative group problems, and class participation. We measure effectiveness by the slope of the regression line between a student’s score (used as a proxy for participation) on a particular course element and his normalized gain on various assessment instruments. These instruments were the MIT final exam comprised mainly of multipart problems demanding analytic responses and two widely used standard physics tests that emphasize conceptual knowledge: the Force Concept Inventory and the Mechanics Baseline Test. The results show that interactive course elements are associated with higher gains on assessment instruments: doing interactive electronic homework administered by myCyberTutor correlated with large gains on the final exam producing a learning effect of 1.8±0.4 standard deviations on the final examination score. myCyberTutor and collaborative group problem solving correlated with gains on the more conceptual tests. We also report surveys that demonstrate that students have had an increasingly favorable opinion of myCyberTutor over the four terms of its use.
North American Paragonimiasis (Caused byParagonimus kellicotti) in the Context of Global Paragonimiasis
Authors: Procop Gary W.
Published: July 2009

Paragonimusspecies are highly evolved parasites with a complex life cycle that involves at least three different hosts, i.e., snails, crustaceans, and mammals. The adult forms ofParagonimusspecies reside and mate in the lungs of a variety of permissive mammalian hosts, including humans. Although human paragonimiasis is uncommonly encountered in North America, both autochthonous and imported disease may be encountered.Paragonimus kellicotti, the species endemic to North America, is a well-known pathogen in wild and domestic animals. Five patients with North American paragonimiasis have been reported in the recent medical literature. The biologic, clinical, radiologic, and laboratory features of paragonimiasis are reviewed, with emphasis on North American paragonimiasis whenever possible.
Resistance to Therapies for Infection byPlasmodium vivax
Authors: Baird J. Kevin
Published: July 2009

The gravity of the threat posed by vivax malaria to public health has been poorly appreciated. The widely held misperception ofPlasmodium vivaxas being relatively infrequent, benign, and easily treated explains its nearly complete neglect across the range of biological and clinical research. Recent evidence suggests a far higher and more-severe disease burden imposed by increasingly drug-resistant parasites. The two frontline therapies against vivax malaria, chloroquine and primaquine, may be failing. Despite 60 years of nearly continuous use of these drugs, their respective mechanisms of activity, resistance, and toxicity remain unknown. Although standardized means of assessing therapeutic efficacy against blood and liver stages have not been developed, this review examines the provisional in vivo, ex vivo, and animal model systems for doing so. The rationale, design, and interpretation of clinical trials of therapies for vivax malaria are discussed in the context of the nuance and ambiguity imposed by the hypnozoite. Fielding new drug therapies against real-world vivax malaria may require a reworking of the strategic framework of drug development, namely, the conception, testing, and evaluation of sets of drugs designed for the cure of both blood and liver asexual stages as well as the sexual blood stages within a single therapeutic regimen.
EFFECT OF LOGARITHMIC MESONIC POTENTIAL ON NUCLEON PROPERTIES
Authors: ABU-SHADY M.
Published: July 2009

A linear sigma model with logarithmic mesonic potential is proposed for computing nucleon properties. The logarithmic potential is based on some aspects of QCD. The field equations have been solved in mean-field approximation. Obtained results for nucleon properties are good in comparison with the original model and agree with measured data.
ONCE AGAIN ON THIN-SHELL WORMHOLES IN SCALAR–TENSOR GRAVITY
Authors: BRONNIKOV KIRILL A. , STAROBINSKY ALEXEI A.
Published: July 2009

It is proved that all thin-shell wormholes built from two identical regions of vacuum static, spherically symmetric spacetimes have a negative shell surface energy density in any scalar–tensor theory of gravity with a non-ghost massless scalar field and a non-ghost graviton.
NEUTRINO ASTRONOMY WITH ICECUBE
Authors: DeYOUNG TYCE
Published: July 2009

IceCube is a kilometer-scale high energy neutrino telescope under construction at the South Pole, a second-generation instrument expanding the capabilities of the AMANDA telescope. The scientific portfolio of IceCube includes the detection of neutrinos from astrophysical objects such as the sources of the cosmic rays, the search for dark matter, and fundamental physics using a very large data set of atmospheric neutrinos. The design and status of IceCube are briefly reviewed, followed by a summary of results to date from AMANDA and initial IceCube results from the 2007 run, with 22 of a planned 86 strings operational. The new infill array known as Deep Core, which will extend IceCube's capabilities to energies as low as 10 GeV, is also described.
TWISTED ACYCLICITY OF A CIRCLE AND SIGNATURES OF A LINK
Authors: VIRO OLEG
Published: July 2009

Homology of the circle with non-trivial local coefficients is trivial. From this well-known fact we deduce geometric corollaries involving codimension-two links. In particular, the Murasugi–Tristram signatures are extended to invariants of links formed of arbitrary oriented closed codimension two submanifolds of an odd-dimensional sphere. The novelty is that the submanifolds are not assumed to be disjoint, but are transversal to each other, and the signatures are parametrized by points of the whole torus. Murasugi–Tristram inequalities and their generalizations are also extended to this setup.
A SIMPLE FORMULA FOR THE CASSON–WALKER INVARIANT
Authors: MATVEEV SERGEI , POLYAK MICHAEL
Published: July 2009

Gauss diagram formulas are extensively used to study Vassiliev link invariants. Now we apply this approach to invariants of 3-manifolds, considering manifolds given by surgery on framed links in the 3-sphere. We study the lowest degree case — the celebrated Casson–Walker invariant of rational homology spheres. This paper is dedicated to a detailed treatment of 2-component links; a general case will be considered in a forthcoming paper. We present simple Gauss diagram formulas for the Casson–Walker invariant. This enables us to understand/separate its dependence on the unframed link and on the framings. We also obtain skein relations for the Casson–Walker invariant under crossing changes, and study its asymptotic behavior when framings tend to infinity. Finally, we present results of extensive computer calculations.
AN INVARIANT FOR SINGULAR KNOTS
Authors: JUYUMAYA J. , LAMBROPOULOU S.
Published: July 2009

In this paper we introduce a Jones-type invariant for singular knots, using a Markov trace on the Yokonuma–Hecke algebras Y d,n(u) and the theory of singular braids. The Yokonuma–Hecke algebras have a natural topological interpretation in the context of framed knots. Yet, we show that there is a homomorphism of the singular braid monoid SBn into the algebra Y d,n(u). Surprisingly, the trace does not normalize directly to yield a singular link invariant, so a condition must be imposed on the trace variables. Assuming this condition, the invariant satisfies a skein relation involving singular crossings, which arises from a quadratic relation in the algebra Y d,n(u).
SIMULTANEOUS METACARPOPHALANGEAL JOINT ULNAR COLLATERAL LIGAMENT INJURY AND CARPOMETACARPAL DISLOCATION OF THE THUMB IN A FOOTBALL PLAYER: A CASE REPORT
Authors: Bhargava Amit , Jennings Andrew G.
Published: July 2009

An unusual case of ulnar collateral ligament avulsion in association with carpometacarpal dislocation of thumb is described. Symptoms and deformity caused by dislocation can mask the presence of injuries such as damage to the ulnar collateral ligament of thumb. This may lead to long term disability. A high index of suspicion and good clinical examination allows correct diagnosis and management of these uncommon injuries leading to a good clinical outcome.
ULNAR-SIDED WRIST PAIN AFTER FOUR-CORNER FUSION IN A PREVIOUSLY-ASYMPTOMATIC ULNAR POSITIVE WRIST: A CASE REPORT
Authors: Gong Hyun Sik , Jeon Su Ha , Baek Goo Hyun
Published: July 2009

Scaphoid excision and four-corner fusion is one of the treatment choices for patients who have stage II or III SLAC (scapholunate advanced collapse)/SNAC (scaphoid non-union advanced collapse) wrist arthritis. We report a case of ulnar-sided wrist pain which occurred after four-corner fusion for stage II SNAC wrist with a previously-asymptomatic ulnar positive variance, and was successfully treated by ulnar shortening osteotomy. This case highlights a possible coincidental pathology of the ulnocarpal joint in the setting of post-traumatic radiocarpal arthrosis.
IRREDUCIBLE SIMULTANEOUS DISLOCATION OF BOTH INTERPHALANGEAL JOINTS IN THE LITTLE FINGER: A CASE REPORT
Authors: Hara Kazuo , Uchiyama Shigeharu , Kato Hiroyuki
Published: July 2009

We present a case with irreducible simultaneous dislocation of both the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints in the little finger. A combination of the delay from injury to closed reduction and the entrapped flexor digitorum profundus (FDP) tendon at the PIP joint prevented closed reduction from being performed. To our knowledge, this is the first report of such a condition.
CLOSING RADIAL WEDGE OSTEOTOMY FOR PREISER'S COMBINED WITH KIENBÖCK'S DISEASE: TWO CASE REPORTS
Authors: Hayashi Ousuke , Sawaizumi Takuya , Ito Hiromoto
Published: July 2009

Avascular necrosis involving more than one carpal bone is rare, and the appropriate treatment for this condition has not yet been established. In this report, two patients with concomitant Preiser's and Kienböck's disease who also had severe wrist pain without obvious traumas were treated by closing radial wedge osteotomy (CRWO). Clinical evaluation showed that CRWO was effective against both conditions and indicated that it is more suitable for early stage than stage II diseases of the Hebert and Lichtman classifications.
RADIOLUNATE FUSION WITH DISTRACTION USING CORTICOCANCELLOUS BONE GRAFT FOR MINIMIZING DECREASE OF WRIST MOTION IN RHEUMATOID WRISTS
Authors: Masuko Tatsuya , Iwasaki Norimasa , Ishikawa Jun-ichi , Kato Hiroyuki , Minami Akio
Published: July 2009

Radiolunate fusion is a limited carpal fusion procedure used for patients with rheumatoid arthritis. However, this procedure inevitably causes decreases in range of motion, especially wrist flexion. Linscheid and Dobyns described the possibility of minimizing the decrease in motion at the radiocarpal joint by slight distraction of the joint. We hypothesized for our modified procedure that a corticocancellous bone graft was inserted between the radius and the lunate with a small amount of over-correction could provide slight distraction of radioscaphoid joint and protect the joint from decreased range of motion after arthrodesis. Twelve wrists in ten patients with rheumatoid arthritis underwent radiolunate fusion. Mean age at operation was 53 years old and mean follow-up period was 5.7 years. Clinical evaluation and radiological assessment showed that decrease in range of motion was minimized compared with other procedures. Because our modified procedure can minimize decrease in motion, it is recommended.
A BLAUTH IIIB HYPOPLASTIC THUMB RECONSTRUCTED WITH A VASCULARISED METATARSO-PHALANGEAL JOINT TRANSFER: A CASE REPORT WITH 28 YEARS OF FOLLOW UP
Authors: Matsuzaki Hironori , Toishi Satoshi , Yoshizu Takae
Published: July 2009

We reconstructed the Blauth-IIIB hypoplastic right thumb of a 16-year-old girl with a vascularised metatarso-phalangeal (MTP) joint from her second toe combined with a dorsalis-pedis flap. Abduction was provided with an abductor policis long tendon advancement, and adduction, with an extensor indicis proprius tendon transfer. Opponoplasty was performed one year later using the flexor sublimis (IV) tendon. The transferred joint remained functional and non-osteoarthritic 28 years later. Radial and palmar abduction of the reconstructed thumb was 45° and 75° respectively. The index, middle, and ring fingers could oppose the thumb, however she grasped small objects between her index and middle fingertips. If a pollicisation using the index finger is not accepted, the reconstruction described here is one of the surgical options. However donor-foot morbidity is not negligible. Currently, we use a proximal-interphalangeal joint transfer with an opponoplasty using an abductor digiti minimi as a first choice, when planning a reconstruction of preserved hypoplasic thumb.
DUPUYTREN'S DISEASE CONFINED TO THE INTERPHALANGEAL JOINTS: A CASE REPORT
Authors: Saleh Waleed Riad , Horii Emiko , Hirata Hitoshi
Published: July 2009

A typical case of Dupuytren's contracture confined to the interphalangeal joints of the right little finger, occurred in a 79-year-old man. No past history of risk factors or family history of Dupuytren's disease could be detected. Excisions of the abnormal cords lead to good clinical outcome.
A QUADRATIC REGRESSION PROBLEM FOR TWO-STATE ALGEBRAS WITH AN APPLICATION TO THE CENTRAL LIMIT THEOREM
Authors: BOŻEJKO MAREK , BRYC WŁODZIMIERZ
Published: July 2009

We extend the free version8 of the Laha–Lukacs theorem to probability spaces with two states. We then use this result to generalize the noncommutative central limit theorem of Kargin23 to the two-state setting.
QUASI-REGULAR DIRICHLET FORMS ON FREE RIEMANNIAN PATH SPACES
Authors: WANG FENG-YU , WU BO
Published: July 2009

The integration by parts formula on free path spaces over noncompact Riemannian manifolds is established for initial distributions with densities in [Formula: see text]. As an application, a large class of Dirichlet forms with (unbounded and non-constant) diffusion coefficients are constructed on free Riemannian path spaces, which are quasi-regular under mild curvature conditions.
COMBINATORIAL RELATION BETWEEN FREE CUMULANTS AND JACOBI PARAMETERS
Authors: MŁOTKOWSKI WOJCIECH
Published: July 2009

We find a formula which expresses free and conditionally free cumulants in terms of Jacobi parameters. This leads to some necessary conditions for free and conditionally free infinite divisibility. We also express conditionally free cumulants of two measures in terms of their free cumulants.
GROWTH ESTIMATES FOR DISCRETE QUANTUM GROUPS
Authors: BANICA TEODOR , VERGNIOUX ROLAND
Published: July 2009

We discuss the notion of growth for discrete quantum groups, with a number of general considerations, and with some explicit computations. Of particular interest is the quantum analogue of Gromov's estimate regarding polynomial growth: we formulate the precise question, and we verify it for the duals of classical Lie groups.
A NOTE ON VARIATIONAL SOLUTIONS TO SPDE PERTURBED BY GAUSSIAN NOISE IN A GENERAL CLASS
Authors: RÖCKNER MICHAEL , WANG YI
Published: July 2009

This note deals with existence and uniqueness of (variational) solutions to the following type of stochastic partial differential equations on a Hilbert space [Formula: see text][Formula: see text] where A and B are random nonlinear operators satisfying monotonicity conditions and G is an infinite dimensional Gaussian process adapted to the same filtration as the cylindrical Wiener process W(t),t ≥ 0.
FINITE GEOMETRIES WITH QUBIT OPERATORS
Authors: SENGUPTA AMBAR N.
Published: July 2009

Finite projective geometries, especially the Fano plane, have been observed to arise in the context of certain quantum gate operators. We use Clifford algebras to explain why these geometries, both planar and higher dimensional, appear in the context of multi-qubit composite systems.
THE ONTOGENY OF SCALE-FREE SYNTAX NETWORKS: PHASE TRANSITIONS IN EARLY LANGUAGE ACQUISITION
Authors: COROMINAS-MURTRA BERNAT , VALVERDE SERGI , SOLÉ RICARD
Published: July 2009

Language development in children provides a window to understand the transition from protolanguage to language. Here we present the first analysis of the emergence of syntax in terms of complex networks. A previously unreported, sharp transition is shown to occur around two years of age from a (pre-syntactic) tree-like structure to a scale-free, small world syntax network. The development of these networks thus reveals a nonlinear dynamical pattern where the global topology of syntax graphs shifts from a hierarchical, tree-like pattern, to a scale-free organization. Such change seems difficult to be explained under a self-organization framework. Instead, it actually supports the presence of some underlying innate component, as early suggested by some authors.
COMPARISON OF PEDESTRIAN FUNDAMENTAL DIAGRAM ACROSS CULTURES
Authors: CHATTARAJ UJJAL , SEYFRIED ARMIN , CHAKROBORTY PARTHA
Published: July 2009

The relation between speed and density is connected with every self-organization phenomenon of pedestrian dynamics and offers the opportunity to analyze them quantitatively. But even for the simplest systems, like pedestrian streams in corridors, this fundamental relation is not completely understood. A comparison of data from literature shows that specifications in text books as well as measurements under various experimental conditions differ significantly. In this contribution it is studied whether cultural influences and length of the corridor can be the causes for these deviations. To reduce as much as possible unintentional effects, a system is chosen with reduced degrees of freedom and thus the most simple system, namely the movement of pedestrians along a line under closed boundary conditions. It is found that the speed of Indian test persons is less dependent on density than the speed of German test persons. Surprisingly the more unordered behavior of the Indians is more effective than the ordered behavior of the Germans. This may be due to differences in their self-organization behavior. Without any statistical measure one cannot conclude about whether there are differences or not. By hypothesis test it is found quantitatively that these differences exist, suggesting cultural differences in the fundamental diagram of pedestrians.
MODULATED EXPLORATORY DYNAMICS CAN SHAPE SELF-ORGANIZED BEHAVIOR
Authors: HESSE FRANK , DER RALF , HERRMANN J. MICHAEL
Published: July 2009

We study an adaptive controller that adjusts its internal parameters by self-organization of its interaction with the environment. We show that the parameter changes that occur in this low-level learning process can themselves provide a source of information to a higher-level context-sensitive learning mechanism. In this way, the context is interpreted in terms of the concurrent low-level learning mechanism. The dual learning architecture is studied in realistic simulations of a foraging robot and of a humanoid hand that manipulated an object. Both systems are driven by the same low-level scheme, but use the second-order information in different ways. While the low-level adaptation continues to follow a set of rigid learning rules, the second-order learning modulates the elementary behaviors and affects the distribution of the sensory inputs via the environment.
THE CAT, THE FLY AND THE BEETLE — WHY GENETICS NEEDS A SEMANTIC EDUCATION
Authors: PADMANABHAN SANDOSH , HASTIE CLAIRE , SAINSBURY CHRISTOPHER A. , MCBRIDE MARTIN W. , CONNELL JOHN M. , DOMINICZAK ANNA F.
Published: July 2009

Major advances have been made in the understanding of the genetic basis of diseases since Mendel's publication of the results of plant breeding experiments in 1866. To date these advances have been largely confined to the monogenic disorders — caused by mutations in a single gene. The public-health implications of these advances is relatively limited. In this review we explore our current understanding of the genetic basis of human traits and the reasons why current theories may account for the difficulties in identifying the genes for common diseases. We then postulate that semantic computing may be rightly poised to help understand complex disease causation, and explore the efforts that have been made to date to develop the necessary technological approach to the problem.
A PEER DATA SHARING SYSTEM COMBINING SCHEMA AND DATA LEVEL MAPPINGS
Authors: RAHMAN MD. ANISUR , MASUD MD. MEHEDI , KIRINGA ILUJU , EL SADDIK ABDULMOTALEB
Published: July 2009

Peer data sharing systems use either schema-level or data-level mappings to resolve schema as well as data heterogeneity among data sources (peers). Schema-level mappings create structural relationships among different schemas. On the other hand, data-level mappings associate data values in two different sources. These two kinds of mappings are complementary to each other. However, existing peer database systems have been based solely on either one of these mappings. We believe that if both mappings are addressed simultaneously in a single framework, the resulting approach will enhance data sharing in a way such that we can overcome the limitations of the non-combined approaches.

In this paper, we present a model of a peer database management system which allows a bi-level mapping that combines schema-level and data-level mappings into a single relational framework. We present the syntax and semantics of this new kind of mappings. Furthermore, we present an algorithm for query translation that uses the bi-level mappings. Our algorithm relies on tableau for expressing both queries and mappings.
Impact of Gate Dielectric Breakdown Induced Microstructural Defects on Transistor Reliability
Authors: Li Xiang , Pey Kin Leong , Lo Vui Lip , Ranjan Rakesh , Tung Chih Hang , Tang Lei Jun
Published: July 2009

The impact of gate dielectric breakdown induced microstructural defects is investigated for both conventional poly-Si/SiON and metal-gate/high-k gate stacks. For poly-Si/SiON gate stacks, the effect of dielectric-breakdown induced epitaxy (DBIE) dilation on the post breakdown degradation rate is discussed. It was found that oxygen vacancy and Si-path formation in the breakdown path control the post-breakdown evolution from digital mode to analog mode which has significant impact on the post breakdown reliability margin. For metal-gate/high-k gate stacks, ultrafast degradation could happen with formation of metal filament if the compliance current level exceeds certain limit. However, the gate leakage current could recover from the breakdown damage by the reverse electrical biasing. The diffusion of oxygen atoms in and out of the breakdown path makes the ON/OFF switching of the percolation path possible.
Time-to-Breakdown Behavior and Mechanism on U-grooved n-MOSFET
Authors: Seo Jae Yong , Park Hong Sik , Kang Gu Gwan , Kang Ju Seong , So Byung Se
Published: July 2009

The bi-modal breakdown processes can well explain the lifetime model in grooved gate oxide with rounded local structure. We have clarified for the first time that the gate oxide reliability is strongly dependant on the tunneling characteristics in the rounded channel of the center and the N+ junction edge corners
TFT Technology Programs in China
Authors: Xiong Shaozhen , Meng Zhiguo , Wu Chunya , Li Juan , He Jie , Zhang Fang
Published: July 2009

The research programs on TFT-FPDs supported by Chinese government in the past several "Five-Years Plans" have been reviewed in brief. Recently, a proposal for screwing up the development of the industries of electronics and information in China approved by State Department of China has been reported. The example of research on TFT-FPDs in Nankai University is introduced orderly.
From Amorphous-Si Thin-Film-Transistors to Single Crystal-Si Transistors: Influence of Si Crystallinity on Device Properties
Authors: Templier Francois
Published: July 2009

Silicon, under its various phases from amorphous (a-Si:H) to monocrystalline, with intermediates microcrystalline (µc-Si:H) and polycrystalline, can be used to manufacture devices with very different characteristics. We have investigated some links between device characteristics and material crystallinity. Carrier mobility is strongly dependant on defects with energy levels within the semiconductor bandgap, and these defects are reduced when crystal order is increased. The reduced drain leakage current in a-Si:H in comparison with microcrystalline (µc-Si:H) Thin-Film Transistors (TFTs) is explained by differences in material properties related to crystallinity. Finally, it is shown that µc-Si:H TFTs exhibit better threshold voltage (Vth) stability than a-Si:H ones. Investigation of Vth drift mechanisms indicates that this is related to improvement of the semiconductor material quality.
Single Grain Si TFTs for RF and 3D ICs
Authors: Ishihara Ryoichi , Baiano Alessandro , Chen Tao , Derakhshandeh Jaber , Tajari Mofrad M. R. D. , Danesh Mina , Saputra Nitz , Long John R. , Beenakker C. I.
Published: July 2009

Single-grain Si TFTs have been fabricated using accurate 2D location control of large Si grain with the μ-Czochralski process. TFTs fabricated inside the crystalline islands of 6 μm show a mobility (600cm2/Vs) as high as that of the SOI counterpart, despite of the low-temperature (<350oC) process. By applying a tensile stress into the grain, the mobility surpass even the SOI counterparts. We have succeeded in controlling crystallographic orientation of the location-controlled Si grains as well, by combination of metal induced lateral crystallization and the micro-Czochralski process. Owing to the orientation control, uniformity in device properties approaches to the level of the SOI counterpart. Using the high performance single-grain (SG) Si TFTs, we have fabricated RF amplifier. The cut-off frequency of the RF device is 5.5 GHz with a channel length of 1.5 μm. We have even succeeded to stack two SG-TFT layers with which CMOS inverters were fabricated. This will open several new applications in TFTs of RF wireless communication, 3D-ICs with device level integration, and flexible electronics.
High Scalability and Low Variability of Planar Fully Depleted SOI MOSFETs
Authors: Weber Olivier , Andrieu Francois , Fenouillet-Béranger Claire , Buj-Dufournet Christel , Barral Vincent , Perreau Pierre , Tosti Lucie , Brevard Laurent , Faynot Olivier
Published: July 2009

We review recent results obtained on ultra-thin body SOI at CEA-LETI and STMicroelectronics to address the 22nm CMOS technology node and beyond. For such scaled devices, variability of threshold voltage (VT) is now widely recognized as one of the most critical challenges, especially for dense SRAM cells. Fully Depleted (FD) SOI MOSFETs, with its undoped channel, are proposed here as a solution to overcome this issue: The lowest variability compared to bulk and FinFETs devices has been recently reported in planar devices down to 25nm gate length. Thinning SOI and BOX thicknesses has been also investigated as solutions to scale further this planar FDSOI technology. All these experimental results make the planar FDSOI technology one of the best candidate for the low power 22nm technology node and beyond.
Selective Epitaxy of Si and SiGe for Future MOS Devices
Authors: Mizushima Ichiro
Published: July 2009

Selective epitaxial growth of Si and SiGe films has been applied to the fabrication of many high-performance MOSFETs, because new device structures can be realized by selective epitaxial growth. Selective growth of Si and SiGe at the source/drain region is the most well-known example. Selective growth on S/D region is especially important for FinFETs, which is one of the most promising candidate for future MOS devices. By using selective epitaxy of Si:C, precise device design can be realized. Multi-stacked structure, which is also a candidate for next-generation devices, can be fabricated with SiGe epitaxial growth.
Substrate Engineering for 32nm and Beyond
Authors: Nguyen Bich-Yen , Mazuré Carlos , Celler George
Published: July 2009

As Si CMOS technology progresses to more advanced nodes, classical scaling is no longer sufficient to follow Moore's law. A transition to engineered substrate technology is essential, as exemplified by SOI and its more advanced adaptations. The advances in engineered substrates and some key applications are described.
Atomically Controlled Processing for Group IV Semiconductors
Authors: Murota Junichi , Sakuraba Masao
Published: July 2009

One of the main requirements for Si-based ultrasmall device is atomic-order control of process technology. Here, we show the concept of atomically controlled processing for group IV semiconductors based on atomic-order surface reaction control in Si-based CVD epitaxial growth. Self-limiting formation of 1-3 atomic layers of group IV or related atoms in the thermal adsorption and reaction of hydride gases on Si(100) and Ge(100) are generalized based on the Langmuir-type model. Moreover, Si or Si1-xGex epitaxial growth over N, P or C layer already-formed on Si(100) or Si1-xGex(100) surface is achieved and the capability of atomically controlled processing for advanced devices is demonstrated. Additionally, the strain control of the Si1-xGex/Si heterostructure due to stripe patterning is discussed.
Atomic Layer Doping for Future Si Based Devices
Authors: Tillack Bernd , Yamamoto Yuji
Published: July 2009

The concept of atomic-level processing based on atomic-order surface reaction control is discussed. The main idea of the atomic layer approach is the control of the process by surface reactions at very low temperatures (even at room temperature). Results of B and P atomic layer doping of Si, Ge and SiGe are reviewed and discussed focussing on the control of the surface adsorption by changing temperatures and partial pressures of the dopant gases. For B atomic layer doping of SiGe and pure Ge using B2H6, high doping levels and steep doping profiles have been reached. The process was found to be self-limited at ~100{degree sign}C indicating preferred adsorption of B2H6 on Si and Ge sites and suppression of B cluster formation. In the case of B atomic layer doping of Si it is shown that the technique can be used for the selective deposition of polycrystalline Si. For P atomic layer doping of SiGe self-limitation of the process has been observed for temperatures between 200-550{degree sign}C allowing very precise dopant dose and location control.
Surface Roughening and Microstructure of Tantalum Nitride Films Sputtered at Different N2/Ar Flow Ratios
Authors: Yang Ji J. , Liu Bo , Wang Yuan , Xu Ke W.
Published: July 2009

Tantalum nitride (Ta-N) films with different thicknesses varying from 50 nm to 1000 nm were deposited on Si(111) substrates by reactive magnetron sputtering as a function of N2/Ar flow ratio. Microstructure and surface morphology were investigated by using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. With increasing N2/Ar flow ratio, the film structures undergo a gradual transition from polycrystalline structure to amorphous along with the changes of phase composition. Film surface roughness Rrms first increases and then decreases.
A-Si:H TFT Nonvolatile Memories and Copper Interconnect for Rigid and Flexible Electronics
Authors: Kuo Yue
Published: July 2009

The floating-gate a-Si:H TFT is a low temperature prepared nonvolatile memory device that can be fabricated on a rigid or flexible substrate. Copper interconnect lines are necessarily for large-area flat panel displays and other electronics products. For flexible electronic applications, they are subject to mechanical bending. In this paper, the author reviewed recent progress on influences of mechanical bending on memory functions of the floating-gate a-Si:H TFT and the failure mode of the copper line etched with a new plasma-based etch process. Their corresponding characteristics on flat substrates were also investigated and compared.