bluuebunny/crossref_metadata_2025 huggingface dataset:
G.W. Bush and North Korea: A Levels of Analysis View
Authors: Martin Curtis H.
Published: August 2010

This study describes and evaluates, from the perspective of pertinent system, state, and individual level theory, the unfolding of the Bush administration's strategy for addressing the North Korea nuclear issue up to the February 2007 Beijing agreement on first steps toward denuclearization of the Korean peninsula. It will explore whether that policy has been “effective harmony of different goals,” as the administration has claimed, or something far less coherent and effective. At its inception, the administration's policy was grounded in a strong– though by no means universally held–preference for “asphyxiation” rather than “oxygen,” for pressure and isolation rather than for rewards. However, this default policy was constrained at almost every turn by system and state level realities that drove the United States to eschew forceful unilateral action and to pursue its objectives through multilateral regional diplomacy. And yet throughout the years of six‐party talks, the strong preference of core decision makers for isolation continued–pending what they hoped would be a more propitious environment to pursue a forward leaning policy–to rein in U.S. negotiators. As a result, U.S. policy often appeared to exhibit characteristics of “temporary appeasement,”“hawk engagement” and “malign neglect” in which negotiations assume a primarily tactical role rather than a wholehearted effort to engage the DPRK. The apparent success of financial sanctions, coupled with the international shock wave that followed North Korea's missile and nuclear tests, might have been expected to give administration hawks the long‐awaited opportunity to pursue their default policy. Despite the successes enjoyed by new financial sanctions, however, U.S. policy remained as constrained as ever by the grave deterioration of the United States' position in the Middle East and the unanticipated shift of power in congress. These constraints may in part explain the dramatic about‐face in the administration's position that led ultimately to the February 13, 2007 agreement to offer the DPRK an “early harvest” in exchange for initial steps toward denuclearization.
The Environmental Civil Society and the Transformation of State‐Society Relations in China: Building a Tri‐level Analytical Framework
Authors: Lin Teh‐chang , Lin Jean Yen‐chun
Published: August 2010

State‐society relations is a conventional tool used in analyzing the relational behavioral pattern of between the state and the society. In China, market reforms and open policy since 1978 have engendered the growth of environmental civil society organizations and thereby enhanced the changes in the nature of state‐society relations. However, the analysis of Chinese state‐society relations has in the past largely been two‐dimensional, focusing on domestic relations. However, changing patterns of state‐society relations in China has called for a more elaborate tri‐level analytical framework of the state, its main civil society representative, domestic non‐governmental organizations, and international non‐governmental organizations. Through the study of environmental protests such as anti‐dam construction demonstrations, we have found that domestically, Chinese environmental nongovernmental organizations not only act as a challenger to the state, but at times collaborate with the state. From an external perspective, international non‐governmental organizations not only directly challenge the Chinese state, but also network with local Chinese NGOs in their protests. This article thus adds a new level to the conventional analysis of state‐society relations in China.
The Politics of NGOs and Democratic Governance in South Korea and Japan
Authors: Lee Sook‐Jong , Arrington Celeste
Published: August 2010

The growing number of non‐governmental organizations (NGOs) is fundamentally reshaping the balance of power and the roles of NGOs in democratic governance in Japanese and Korean politics, but in distinctive ways. Korean advocacy NGOs influence policymaking by focusing on politics at the center, while Japanese NGOs achieve influence by focusing on local politics. Whereas Korean NGOs tend to be contentious and politicized, Japanese NGOs adopt more pragmatic and cooperative stances. What factors explain these significant differences in the character of NGOs and the patterns of their participation in democratic politics in Japan and Korea? This paper argues that the effects of the historical development of civil society are essential components to any explanation of the patterns of NGOs’ relations with the government and the public and their organizational structure and strategies. Civic associations in both countries have both exploited and been empowered by developments in party politics, the public's receptiveness to NGOs, and state actors’ attitudes toward NGOs. By comparing NGOs in Japan and Korea, this paper aims to enhance our understanding of the similarities and differences in both countries’ civil societies, as well as of the factors that have led to these distinctive patterns of NGO politics.
Shaping State Identity: International Law and Whaling in Japan
Authors: Flowers Petrice R.
Published: August 2010

This article revisits the issue of whaling in an attempt to account for Japan's decision to observe the temporary moratorium on commercial whaling at the end of the 1986 whaling season and to remain a member of the International Whaling Commission despite increasingly restrictive regulations. This analysis develops an argument that focuses on the social aspects of international agreements, especially the role of international law in shaping state identity and (re)producing difference.
Reinventing the Interventionist State: The Korean Economic Bureaucracy Reform under the Economic Crisis
Authors: Jung Joo‐Youn
Published: August 2010

While market institutions experience extensive neoliberal reforms facing the exogenous pressure for economic openness and liberalization, what institutional changes have taken place within the old interventionist state apparatuses, especially the economic bureaucracies in the state‐led economies? This paper attempts to shed light on this question by analyzing the institutional reform process of the powerful South Korean economic bureaucracy, the Ministry of Finance and Economy (MOFE), in the aftermath of the Asian financial crisis in 1997. Drawing attention to the politics of the MOFE reform, this paper shows that the financial crisis opened a rare window of opportunity to the reformist political leader, President Kim Dae‐Jung. President Kim actively reinterpreted the challenges posed by the financial crisis and utilized them as a rationale for establishing a new agency, the

Ministry of Planning and Budget (MPB)

, to strengthen his reform initiative in post‐crisis Korea. Despite the façade of neoliberal ideals and slogans for deregulation, the essential goal of the key actors involved in the reform policy‐making process and the final institutional choices made by them were both a far cry from the retreat of the interventionist economic bureaucracy. The active political intervention in the process of bureaucratic institutional reform, as well as the evolution of the MPB's functions since the financial crisis, suggests that it is too simplistic to argue that the Korean interventionist state will simply wither away in the era of economic globalization.
Making overall dynamic body acceleration work: on the theory of acceleration as a proxy for energy expenditure
Authors: Gleiss Adrian C. , Wilson Rory P. , Shepard Emily L. C.
Published: August 2010

1. The energetic costs of different behaviours are critical in modulating the behavioural ecology of free‐living animals. Despite this, measurement of energy expenditure in the field has proved difficult.

2. A new method with broad application for field studies has been proposed for determining the rate at which animals expend energy, based on measurements of overall dynamic body acceleration (ODBA) through the attachment of miniature acceleration data‐loggers. This technique is easy to implement and has the promise to be able to resolve energy expenditure with fine (sub‐second) temporal resolution, making it the only method which promises to able to determine the cost of short‐lived behaviours. Increasing evidence supports the validity of the approach although the rationale behind it is vague.

3. This study explores link between metabolic energy and acceleration by examining what is known about how muscular tissue converts metabolic energy to mechanical work via muscular contraction and how Newtonian physics facilitates a derivation of Power (the rate at which work is performed) from acceleration. The link between metabolic energy and acceleration appears to involve three discrete processes: (i) the ratio of mechanical work to metabolic work performed by a single muscle (mechano‐chemical efficiency); (ii) the ratio of external and internal work performed (mechanical work of the limbs in relation to that of the centre of mass); and (iii) the ratio of inertial to de novo mechanical work. These processes may vary according to the animal’s mass, the medium in which it travels and its gait or behaviour.

4. Assessment of movement has limited application in defining non‐movement energy expenditure such as that involved in specific dynamic action or non‐shivering thermogenesis. However, this non‐movement energy expenditure may often be modelled with reasonable confidence. The utility and appropriateness of the ODBA‐energy expenditure method depends on a set of conditions, which we define and suggest should be assessed a priori.

5. This study explores the framework behind the ODBA‐energy expenditure method to enable informed decisions to be made regarding the suitability for specific research questions addressed, as well as highlighting calibration needs.
Association of owner‐reported noise with findings during dynamic respiratory endoscopy in Thoroughbred racehorses
Authors: WITTE S. H. P. , WITTE T. H. , HARRISS F. , KELLY G. , POLLOCK P.
Published: August 2010

Reasons for performing study:To determine the association between owner‐reported noise and findings during dynamic respiratory endoscopy (DRE) in a large case series.

Hypothesis:The sensitivity of owner‐reported noise for dynamic upper respiratory tract obstructions in horses is low, and the specificity is high.

Methods:One hundred horses underwent DRE for the investigation of abnormal respiratory noise and/or poor performance. The association of abnormal noise with findings during DRE was evaluated.

Results:Eighty‐five horses underwent DRE for the investigation of abnormal respiratory noise. Of these, 82% were found to have one or more obstructive upper respiratory tract abnormalities during DRE. Forty‐eight percent of horses reported to gurgle, rattle or make a rough noise were diagnosed with solitary palatal dysfunction. A further 24% with this history showed palatal dysfunction in combination with an additional abnormality. Twenty‐seven percent of horses with a history of whistling or roaring showed some degree of recurrent laryngeal neuropathy. Seven percent of horses with a history of whistling or roaring had vocal cord collapse as a solitary condition, whereas 40% had vocal cord collapse and another abnormality. The sensitivity of abnormal respiratory noise for any obstruction of the upper portion of the respiratory tract was high (84%), while the specificity was low (25%). Characteristic owner reported noise patterns showed moderate to low sensitivity for specific conditions. Whistling and roaring showed the highest specificity (≥80%) for laryngeal dysfunction.

Conclusion:Diagnosis of upper respiratory tract obstructions based solely on owner‐reported noise and performance history may result in incomplete diagnoses.

Clinical relevance:DRE should be performed in horses with abnormal respiratory noise to rule out complex conditions of the upper portion of the respiratory tract.
Dynamics of Premixed H2/CH4 Flames Under Near Blowoff Conditions
Authors: Zhang Qingguo , Shanbhogue Santosh J. , Lieuwen Tim
Published: August 2010

Swirling flows are widely used in industrial burners and gas turbine combustors for flame stabilization. Several prior studies have shown that these flames exhibit complex dynamics under near blowoff conditions, associated with local flamelet extinction and alteration in the vortex breakdown flow structure. These extinction events are apparently due to the local strain rate irregularly oscillating above and below the extinction strain rate values near the attachment point. In this work, global temporally resolved and detailed spatial measurements were obtained of hydrogen/methane flames. Supporting calculations of extinction strain rates were also performed using detailed kinetics. It is shown that flames become unsteady (or local extinctions happen) at a nearly constant extinction strain rate for different hydrogen/methane mixtures. Based upon analysis of these results, it is suggested that classic Damköhler number correlations of blowoff are, in fact, correlations for the onset of local extinction events, not blowoff itself. Corresponding Mie scattering imaging of near blowoff flames also was used to characterize the spatio-temporal dynamics of holes along the flame that are associated with local extinction.
An Experimentally Validated Numerical Modeling Technique for Perforated Plate Heat Exchangers
Authors: White M. J. , Nellis G. F. , Klein S. A. , Zhu W. , Gianchandani Y.
Published: August 2010

Cryogenic and high-temperature systems often require compact heat exchangers with a high resistance to axial conduction in order to control the heat transfer induced by axial temperature differences. One attractive design for such applications is a perforated plate heat exchanger that utilizes high conductivity perforated plates to provide the stream-to-stream heat transfer and low conductivity spacers to prevent axial conduction between the perforated plates. This paper presents a numerical model of a perforated plate heat exchanger that accounts for axial conduction, external parasitic heat loads, variable fluid and material properties, and conduction to and from the ends of the heat exchanger. The numerical model is validated by experimentally testing several perforated plate heat exchangers that are fabricated using microelectromechanical systems based manufacturing methods. This type of heat exchanger was investigated for potential use in a cryosurgical probe. One of these heat exchangers included perforated plates with integrated platinum resistance thermometers. These plates provided in situ measurements of the internal temperature distribution in addition to the temperature, pressure, and flow rate measured at the inlet and exit ports of the device. The platinum wires were deposited between the fluid passages on the perforated plate and are used to measure the temperature at the interface between the wall material and the flowing fluid. The experimental testing demonstrates the ability of the numerical model to accurately predict both the overall performance and the internal temperature distribution of perforated plate heat exchangers over a range of geometry and operating conditions. The parameters that were varied include the axial length, temperature range, mass flow rate, and working fluid.
Numerical Simulation of the Performance of a Sudden Expansion With Fence Viewed as a Diffuser in Low Reynolds Number Regime
Authors: Chakrabarti S. , Rao S. , Mandal D. K.
Published: August 2010

In this paper, the results of numerical simulation on the performance of a sudden expansion with fence viewed as a diffuser are presented. The two-dimensional steady differential equations for conservation of mass and momentum have been solved using the semi-implicit method for pressure-linked equations (SIMPLE) algorithm. The Reynolds number is in the range of 20–100 and fence subtended angle (FSA) between 10 deg and 30 deg. An aspect ratio of 2 is fixed for all the computations. The effect of each variable on average static pressure and diffuser effectiveness has been studied. Computations have revealed that for higher Reynolds number, the use of a fence always increases the effectiveness of the diffusion process when compared with a simple sudden expansion configuration. In low Reynolds number regime, depending on the positioning of the fence and the fence subtended angle, the fence may increase or decrease the diffuser effectiveness in comparison with sudden expansion without fence.
Assessment of the Spent Life Fraction of Gas Turbine Blades by Coating Life Modeling and Photostimulated Luminescence Piezospectroscopy
Authors: Rinaldi C. , De Maria L. , Mandelli M.
Published: August 2010

This paper describes the application of a double-sided approach to assess the spent life fraction of thermal barrier coatings (TBCs) at local positions of ex-service blades with NiCoCrAlY-Re bond coat and EB-PVD TBC. A life prediction code implemented with inverse problem solution routines was applied to determine the mean local temperature. On the single blade, large differences (>150°C) of mean local temperature were estimated between regions just after the cooling holes and far from them. A self-developed portable photostimulated luminescence piezospectroscopy (PLPS) instrument was also applied and the coating spent life fraction was evaluated with a recently proposed PLPS diagnostic parameter. The spent life fractions evaluated from mean local temperature values were in good agreement with those estimated from PLPS measurements. Lower spent life fractions were found in well cooled regions of all blades, while higher spent life fractions were calculated at the hottest positions of the blades, particularly on components coming from a plant with a double number of starts. The results confirm the reliability of the PLPS technique and its diagnostic capability also for NiCoCrAlY-Re bond coats; both local differences on the single component and blade-to-blade variations in coating spent life can be evidenced in a nondestructive way.
3D RANS Simulation of Turbulent Flow and Combustion in a 5 MW Reverse-Flow Type Gas Turbine Combustor
Authors: Joung Daero , Huh Kang Y.
Published: August 2010

This study is concerned with 3D RANS simulation of turbulent flow and combustion in a 5 MW commercial gas turbine combustor. The combustor under consideration is a reverse flow, dry low NOx type, in which methane and air are partially mixed inside swirl vanes. We evaluated different turbulent combustion models to provide insights into mixing, temperature distribution, and emission in the combustor. Validation is performed for the models in STAR-CCM+ against the measurement data for a simple swirl flame (http://public.ca.sandia.gov/TNF/swirlflames.html). The standard k-ε model with enhanced wall treatment is employed to model turbulent swirl flow, whereas eddy break-up (EBU), presumed probability density function laminar flamelet model, and partially premixed coherent flame model (PCFM) are tried for reacting flow in the combustor. Independent simulations are carried out for the main and pilot nozzles to avoid flashback and to provide realistic inflow boundary conditions for the combustor. Geometrical details such as air swirlers, vane passages, and liner holes are all taken into account. Tested combustion models show similar downstream distributions of the mean flow and temperature, while EBU and PCFM show a lifted flame with stronger effects of swirl due to limited increase in axial momentum by expansion.
Predicted Rotordynamic Behavior of a Labyrinth Seal as Rotor Surface Speed Approaches Mach 1
Authors: Thorat Manish R. , Childs Dara W.
Published: August 2010

Prior one-control-volume (1CV) models for rotor-fluid interaction in labyrinth seals produce synchronously reduced (at running speed), frequency-independent stiffness and damping coefficients. The 1CV model, consisting of a leakage equation, a continuity equation, and a circumferential-momentum equation (for each cavity), was stated to be invalid for rotor surface speeds approaching the speed of sound. However, the present results show that while the 1CV fluid-mechanic model continues to be valid, the calculated rotordynamic coefficients become strongly dependent on the rotor’s precession frequency. A solution is developed for the reaction-force components for a range of precession frequencies, producing frequency-dependent stiffness and damping coefficients. They can be used to define a Laplace-domain transfer-function model for the reaction-force/rotor-motion components. Calculated results are presented for a simple Jeffcott rotor model acted on by a labyrinth seal. The model’s undamped natural frequency is 7.6 krpm. The fluid properties, seal radius Rs, and running speed ω cause the rotor surface velocity Rsω to equal the speed of sound c0 at ω=58 krpm. Calculated synchronous-response results due to imbalance coincide for the synchronously reduced and the frequency-dependent models. For an inlet preswirl ratio of 0.5, both models predict the same log-dec out to ω≈14.5 krpm. The synchronously reduced model predicts an onset speed of instability (OSI) at 10 krpm, but a return to stability at 48 krpm, with subsequent increases in log-dec out to 70 krpm. The frequency-dependent model predicts an OSI of 10 krpm and no return to stability out to 70 krpm. The frequency-dependent models predict small changes in the rotor’s damped natural frequencies. The synchronously reduced model predicts large changes. The stability-analysis results show that a frequency-dependent labyrinth seal model should be used if the rotor surface speed approaches a significant fraction of the speed of sound. For the present example, observable discrepancies arose when Rsω=0.26c0.
Exhaust-Stream and In-Cylinder Measurements and Analysis of the Soot Emissions From a Common Rail Diesel Engine Using Two Fuels
Authors: Kirchen Patrick , Obrecht Peter , Boulouchos Konstantinos , Bertola Andrea
Published: August 2010

The operation and emissions of a four cylinder, passenger car common-rail diesel engine operating with two different fuels was investigated on the basis of exhaust-stream and in-cylinder soot measurements, as well as a thermodynamic analysis of the combustion process. The two fuels considered were a standard diesel fuel and a synthetic diesel (fuel two) with a lower aromatic content, evaporation temperature, and cetane number than the standard diesel. The exhaust-stream soot emissions, measured using a filter smoke number system, as well as a photo-acoustic soot sensor (AVL Micro Soot Sensor), were lower with the second fuel throughout the entire engine operating map. To elucidate the cause of the reduced exhaust-stream soot emissions, the in-cylinder soot temperature and the KL factor (proportional to concentration) were measured using miniature, three-color pyrometers mounted in the glow plug bores. Using the maximum KL factor value to quantify the soot formation process, it was seen that for all operating points, less soot was formed in the combustion chamber using the second fuel. The oxidation of the soot, however, was not strongly influenced by the fuel, as the relative oxidized soot fraction was not significantly different for the two fuels. The reduced soot formation of fuel two was attributed to the lower aromatic content of the fuel. The soot cloud temperatures for operation with the two fuels were not seen differ significantly. Similar correlations between the cylinder-out soot emissions, characterized using the pyrometers, and the exhaust-stream soot emissions were seen for both fuels. The combustion process itself was only seen to differ between the two fuels to a much lesser degree than the soot formation process. The predominant differences were seen as higher maximum fuel conversion rates during premixed combustion at several operating points, when fuel two was used. This was attributed to the lower evaporation temperatures and longer ignition delays (characterized by the lower cetane number) leading to larger premixed combustion fractions.
Life Prediction Method of CC and DS Ni Base Superalloys Under High Temperature Biaxial Fatigue Loading
Authors: Ogata Takashi
Published: August 2010

Polycrystalline conventional casting (CC) and directionally solidified (DS) Ni base superalloys are widely used as gas turbine blade materials. It was reported that the surface of a gas turbine blade is subjected to a biaxial tensile-compressive fatigue loading during a start-stop operation, based on finite element stress analysis results. It is necessary to establish the life prediction method of these superalloys under biaxial fatigue loading for reliable operations. In this study, the in-plane biaxial fatigue tests with different phases of x and y directional strain cycles were conducted on both CC and DS Ni base superalloys (IN738LC and GTD111DS) at high temperatures. The strain ratio ϕ was defined as the ratio between the x and y directional strains at 1/4 cycle and was varied from 1 to −1. In ϕ=1 and −1. The main cracks propagated in both the x and y directions in the CC superalloy. On the other hand, the main cracks of the DS superalloy propagated only in the x direction, indicating that the failure resistance in the solidified direction is weaker than that in the direction normal to the solidified direction. Although the biaxial fatigue life of the CC superalloy was correlated with the conventional Mises equivalent strain range, that of the DS superalloy depended on ϕ. The new biaxial fatigue life criterion, equivalent normal strain range for the DS superalloy was derived from the iso-fatigue life curve on a principal strain plane defined in this study. Fatigue life of the DS superalloy was correlated with the equivalent normal strain range. Fatigue life of the DS superalloy under equibiaxial fatigue loading was significantly reduced by introducing compressive strain hold dwell. Life prediction under equibiaxial fatigue loading with the compressive strain hold was successfully made by the nonlinear damage accumulation model. This suggests that the proposed method can be applied to life prediction of the gas turbine DS blades, which are subjected to biaxial fatigue loading during operation.
Mobility and Geometric Analysis of the Hoberman Switch-Pitch Ball and
Its Variant
Authors: Wei Guowu , Ding Xilun , Dai Jian S.
Published: August 2010

This paper investigates the mobility and kinematics of the Hoberman switch-pitch ball, and particularly, its variant that does not resort to bevel gears. The ball variant is a general case of the Hoberman switch-pitch ball and constitutes the ball. This paper starts from examining the geometry of the ball variant and its composition, and decomposes it into loops containing eight-bar radially foldable linkages. To investigate the eight-bar radially foldable linkage, constraint matrices are developed using the screw-loop equation. This paper extends the study to the ball variant and investigates the singularity and various configurations based on the geometry and kinematics of the ball variant. This leads to the investigation of the Hoberman switch-pitch ball as a special case of the ball variant with bevel gears to simultaneously drive three joints in every vertex of the ball mechanism. The analysis is then followed by a numerical demonstration of the kinematic characteristics of the Hoberman switch-pitch ball.
Computing the Configuration Space for Tracing Paths Between Assembly Modes
Authors: Urízar Mónica , Petuya Víctor , Altuzarra Oscar , Macho Erik , Hernández Alfonso
Published: August 2010

In this paper, the authors present a general methodology for computing the configuration space for three-degree-of-freedom parallel manipulators so that the relation between input and output variables can be easily assessed. Making use of an entity called the reduced configuration space, all solutions of the direct kinematic problem in parallel manipulators are solved. The graphical representation of this entity enables the location of the direct kinematic solutions to be analyzed so as to make use of a wider operational workspace by means of path planning. A descriptive study is presented regarding the diverse possible paths that allow changing between direct kinematic solutions, thus, enlarging the manipulator’s range of motion.
Enhancing PKM Accuracy by Separating Actuation and Measurement: A 3DOF Case Study
Authors: Corbel David , Company Olivier , Krut Sébastien , Pierrot François
Published: August 2010

This paper proposes an approach for enhancing parallel kinematics machine accuracy by separating actuation and measurement. We describe the interest of the separation actuation and measurement concept and define the sensor redundancy used for designing the measurement device. Then, we present the design of a parallel machine-tool prototype with an independent measuring system, MoM3, as well as the optimization of its measuring system. Lastly, we present the control schemes used on the prototype, and provide experimental results to show the efficiency of separation actuation and measurement applied to a machine-tool.
Geometry and Constraint Analysis of the Three-Spherical Kinematic Chain Based Parallel Mechanism
Authors: Zhang Ketao , Fang Yuefa , Fang Hairong , Dai Jian S.
Published: August 2010

This paper presents a three-spherical kinematic chain based parallel mechanism that evolved from an origami fold. The new parallel mechanism with symmetrical structure consists of a base, a platform, and three-spherical six-bar chains as chain-legs connecting to both base and platform via revolute joints. This paper investigates the constraint of the mechanism by constructing a virtual symmetric plane that is based on the three virtual centers of the spherical chains. Revealing the geometric characteristics and constraint disposition of the constraint screw system, singularity is identified related to the constraint configuration based on Grassmann line geometry and dependency of the constraint screw system, leading to selection of the design parameters that avoid the platform singularity.
Design of a Gravity-Balanced General Spatial Serial-Type Manipulator
Authors: Lin Po-Yang , Shieh Win-Bin , Chen Dar-Zen
Published: August 2010

A novel methodology for the design of a gravity-balanced serial-type spatial manipulator is presented. In the design, gravity effects of the system can be completely compensated at any configuration. The gravity balance of the n-DOF manipulator is achieved by the suspensions of only n zero-free-length springs, where each spring is individually fitted between a primary link and its adjacent auxiliary link. No spring has to be installed across the spatial manipulator from a far remote link to ground such that the motion interference among the springs and the links can be prevented. Besides, since the embedded auxiliary links along the primary links of the manipulator form a series of spatial parallelogram revolute-spherical-spherical-revolute modules, the active DOFs of the system remain the same as the primary manipulator and the range of motion of the manipulator will not be hindered. As a result, the n-DOF manipulator can serve the general function of an articulated serial-type manipulator in kinematics. The simulated results of a 6DOF gravity-balanced manipulator modeled on ADAMS shows that the static equilibrium as well as the kinematics of the system can be successfully accomplished by this proposed methodology.
Kinematic and Dynamic Analysis of a Two-Degree-of-Freedom Spherical
Wrist
Authors: Ruggiu M.
Published: August 2010

The present paper proposes the analysis of a spherical wrist with two degrees of freedom for scanning system applications. The wrist consists of two chains of revolute-revolute pairs. A slotted arc connecting the two chains behaves as a further revolute pair. Thus, the mechanism is an overconstrained (meaning of this definition is discussed in this work) single-loop kinematic chain composed of five revolute pairs equivalent to a spherical motion generator since all its axes intersect at a point. Throughout the paper, the kinematic analysis is developed including some details about the workspace, which depends on the design of the slotted arc. The performance index given as the inverse of the condition number is used to measure the performances of the motion of the moving platform of the wrist. The singularity poses found were examined in detail. A simplified dynamic model is proposed that provides the torques suitable for satisfying a given kinematics. Finally, the paper presents a motorized hardware model of the mechanism assembled in the laboratory.
Poiseuille Flow of Reactive Phan–Thien–Tanner Liquids in 1D Channel Flow
Authors: Chinyoka T.
Published: August 2010

We investigate, using direct numerical simulations, the effects of viscoelasticity on pressure driven flows of thermally decomposable liquids in channels. A numerical algorithm based on the finite difference method is implemented in time and space with the Phan–Thien–Tanner as the model for the viscoelastic liquids. The strong dependence of fluid temperature on the Frank–Kamenetskii parameter is shown for various fluid types and the phenomenon of thermal runaway is demonstrated. It is shown that viscoelastic fluids have in general delayed susceptibility to thermal runaway as compared with corresponding inelastic fluids. This paper demonstrates the efficiency of using semi-implicit finite difference schemes in solving transient problems of coupled nonlinear systems. It also provides an understanding of nonisothermal flows of viscoelastic fluids.
Effect of Rotation on Heat/Mass Transfer for an Impingement/Effusion Cooling System
Authors: Hong Sung Kook , Lee Dong Hyun , Cho Hyung Hee
Published: August 2010

In the present study, the effects of the rotating direction on heat/mass transfer in an impingement/effusion cooling system were investigated. The experiments were carried out with three different jet orientations relative to the axis of rotation and two plate spacing. For high H/d with an orthogonal jet orientation, low and nonuniform heat/mass transfer occurred between the effusion holes since the impinging jet was deflected by the Coriolis force. For a small H/d, the jet deflection effect was diminished, and rotation enhanced the heat/mass transfer in the stagnation region.
An Experimental Study on Heat Transfer Around Two Side-by-Side Closely Arranged Circular Cylinders
Authors: Tsutsui Takayuki
Published: August 2010

The present paper describes heat transfer around two side-by-side closely arranged circular cylinders. The flows around two circular cylinders in a side-by-side arrangement can be classified into three flow patterns according to the gap between the two cylinders. The heat transfer characteristics of the cylinders in each flow regime were experimentally investigated. The diameter of the circular cylinders was 40 mm and the gap between the two cylinders varied from 4 mm to 40 mm. The free stream velocity ranged from 4 m/s to 24 m/s, resulting in Reynolds nos. ranging from 1.1×104 to 6.2×104. The local heat transfer coefficient of both cylinders was measured. The overall Nusselt no. of the two cylinders was found to be minimum at G/D(=gap/diameter)=0.4, which is the minimum drag coefficient condition of the two cylinders, too.
Fabrication of antireflection-structured surface using vertical nanowires as an initial structure
Authors: Nagato Keisuke , Moritani Hiroki , Hamaguchi Tetsuya , Nakao Masayuki
Published: August 2010

An antireflection structure was fabricated using vertically synthesized iron oxide nanowires as an initial structure. Iron oxide nanowires can be synthesized by simply annealing a thin Fe film in air. The authors propose a process for transforming these nanowires into an array of cone: An additional thin Cr film is deposited onto the nanowires and then etched by reactive ion etching. As a result of the redeposition of Cr, the vertical nanowires were successfully transformed into conical structures. This antireflection nanostructure is replicated onto a polymer surface by thermal nanoimprinting, and the replicated surface exhibited low reflectivity at all visible wavelengths.
ALMOST PERFECT TELEPORTATION USING 4-PARTITE ENTANGLED STATES
Authors: PRAKASH H. , CHANDRA N. , PRAKASH R. , SHIVANI
Published: August 2010

In a recent paper N. Ba An (Phys. Rev. A68, 022321 (2003)) proposed a scheme to teleport a single particle state, which is superposition of coherent states |α〉 and |-α〉 using a 4-partite state, a beam splitter, and phase shifters and concluded that the probability for successful teleportation is only 1/4 in the limit |α| → 0 and 1/2 in the limit |α| → ∞. In this paper, we modify this scheme and find that an almost perfect success can be achieved if |α|2 is appreciable. For example, for |α|2 = 5, the minimum of average fidelity for teleportation, which is the minimum of sum of the product of probability for occurrence of any case and the corresponding fidelity evaluated for an arbitrary chosen information state, is 0.9999.
A NOVEL METHOD TO SYNTHESIS OF β-TCP/HA BIPHASIC NANOCRYSTALLINE POWDER BY USING BOVINE BONE
Authors: TAVANGARIAN F. , EMADI R. , ROOHANI ESFAHANI S. I.
Published: August 2010

Nanocrystalline biphasic calcium phosphate (BCP) powder was synthesized from natural bovine bone via a very economic process. The bovine bone was annealed at 900°C for 2 h and elemental compositions were qualitatively identified by energy dispersive X-ray spectroscopy (EDS) in the scanning electron microscope (SEM). The calcined bovine bone was powdered and mixed with calcium hydrogen phosphate dihydrate ( CaHPO4·2 H2O , DCPD). After that, the prepared powder was uniaxially pressed into pellets. The pellets were annealed at 900–1200°C and then crushed to obtain nanocrystalline BCP powder. The morphology and microstructure of the BCP powder were studied by SEM. The results showed that the prepared powder consisted of small size and highly agglomerated particles. X-ray diffraction method was utilized to characterize the phase formation and crystallite size of prepared powder. The crystallite sizes of BCP powder calculated by using XRD data were in the range of 20–60 nm.
CONTROL AND SYNCHRONIZATION OF CHAOTIC PENDULUM USING BACKSTEPPING
Authors: VINCENT U. E. , LAOYE J. A. , TELLA A.
Published: August 2010

This study presents a backstepping scheme for the control and synchronization of chaos in the damped-driven pendulum. The method is a systematic design approach and consists of a recursive procedure that skillfully interlaces the choice of a Lyapunov function with the control. With this technique, the chaotic dynamics of the pendulum is stabilized to the stable equilibrium point and the arbitrary bounded function of time f(t) is tracked. It is further shown that the complete synchronization between two identical chaotic pendula can be realized using this method. Numerical simulations are also presented to verify the control approach.
EXPLICIT EXACT SOLUTIONS TO THE (2+1) DIMENSIONAL SINH-POISSON EQUATION
Authors: XIE YUANXI , PENG SHIYU
Published: August 2010

By introducing an auxiliary ordinary differential equation and solving it by the method of variable separation, many explicit exact solutions of the (2+1) dimensional sinh-Poisson equation are presented in a simple manner.
GENERAL THERMOSTATISTICAL PROPERTIES OF A Q-DEFORMED FERMI GAS TRAPPED IN A POWER-LAW POTENTIAL
Authors: CAI SHUKUAN , SU GUOZHEN , CHEN JINCAN
Published: August 2010

The q-deformed Fermi–Dirac distribution derived from the q-fermion algebra is used to study the thermostatistical properties of a q-deformed Fermi gas trapped in a generic power-law potential, and the effects of q-deformation on the properties of the system are discussed. It is shown that q-deformation leads to some novel characteristics compared with those of an original Fermi system. It is found that the effects of q-deformation display different characteristics in the cases of different kinematic characteristics of particles and different shapes of external potentials. The results obtained here present a unified description for the thermostatistical properties of a class of q-deformed as well as original Fermi systems, so that many important conclusions in the literature are included in this paper.
COMPARISON BETWEEN ULTRAFAST GAIN AND PHASE DYNAMICS IN SEMICONDUCTOR OPTICAL AMPLIFIERS
Authors: WANG LI , WANG ZHI , HUANG WEI-PING
Published: August 2010

The ultrafast dynamics of gain and phase in bulk semiconductor optical amplifiers are numerically investigated over a broad band of about 200 nm based on the semiclassical method of density matrix equations. The gain dynamics and phase dynamics are compared in four different bands for 200 fs Gaussian pump pulse. It is predicted that the recovery time of phase may be longer or shorter than that of gain depending on probe wavelengths. Furthermore, phase recovery overshoot may appear at wavelengths shorter than the pump wavelength. These interesting features result from the competition between spectral-hole burning and carrier heating over the whole band.
STUDY ON THE REFRACTIVE NON-LINEARITY OF THREE-PHOTON ABSORBING MEDIA WITH THE Z-SCAN TECHNIQUE
Authors: LU CHANGGUI , CUI YIPING , GU BING , WANG FENG
Published: August 2010

By using the Gaussian beam Z-scan technique with the zeroth-order Hankel transform method, a theoretical study on the refractive non-linearity of the three-photon absorbing media is presented in this work. The normalized transmittance expression of the closed-aperture Z-scan is derived for the medium with three-photon absorption, third- and fifth-order non-linear refractions. At low irradiance, an analytical approximation of the normalized transmittance, which is helpful for unambiguously extracting the simultaneous third- and fifth-order non-linear refractive indexes, and three-photon absorption coefficient, is obtained. By using this method with 80 fs laser pulses, the non-linear refractive properties of a three-photon absorbing dye solution is studied experimentally, which shows a larger fifth-order refractive non-linearity with respect to the third-order one due to the three-photon absorption resonant enhancement.
THz LIGHT PULSE GENERATION AND STORAGE WITHIN AN EMBEDDED OPTICAL WAVEGUIDE SYSTEM
Authors: UDOMARIYASAP P. , NOPPANAKEEPONG S. , MITATHA S. , YUPAPIN P. P.
Published: August 2010

We propose the interesting results of high frequency generation method, which is required to use in the THz regime. A generated system consists of two micro and a nano ring that can be integrated into a signal system which can be employed to generate the large bandwidth by a Gaussian pulse propagating within the ring resonator system. The selected signals can be filtered by using the optical add/drop filter. By controlling the ring parameters, the appropriate output power can be obtained, which can be modified to be suitable in either imaging or communication applications. Moreover, the very wide band of wavelength can be generated and controlled for various applications.
MODELING AND DESIGN OF REALISTIC Si3N4-BASED INTEGRATED OPTICAL PROGRAMMABLE POWER SPLITTER
Authors: URANUS H. P. , HOEKSTRA H. J. W. M. , STOFFER R.
Published: August 2010

Controllable splitting of optical power with a large splitting ratio range is often required in an integrated optical chip, e.g. for the readout of phase-shift in a slow-light sensor. In this work, we report the modeling and design of an integrated optical programmable power splitter consisting of a Y-junction with a programmable phase-shifter cascaded to a directional coupler. We used a vectorial mode solver, and a combination of a transfer matrix method with a 3D vectorial coupled-mode theory (CMT) to compute the power transfer ratio of a realistic device structure made of Si 3 N 4, TEOS, and SiO 2 grown on a Si substrate. In the simulations, waveguide attenuation values derived from the measured attenuation of a prefabricated test wafer, have been taken into account. Vectorial modal fields of individual waveguides, as computed by a mode solver, were used as the basis for the CMT computation. In the simulation, an operational wavelength around 632.8 nm was assumed. Our simulations reveal that maximum power splitting ratio can be achieved when the directional coupler is operated as a 3-dB coupler with the phase-shifter set to produce a 90° phase-shift. The required coupler length for such desired operating condition is highly-dependent on the gap size. On the other hand, the inclusion of the waveguide loss and the non-parallel section of the directional coupler into the model only slightly affect the results.
STUDY OF MICROSTRUCTURE AND OPTICAL PROPERTIES OF PVA-CAPPED ZnS: Cu NANOCRYSTALLINE THIN FILMS
Authors: THI TRAN MINH , VAN BUI HONG , BEN PHAM VAN
Published: August 2010

A study has been carried out on the Cu doping and PVA capping induced optical property changes in ZnS : Cu nanocrystalline powders and thin film. For this study, ZnS : Cu nanopowders with Cu concentrations of 0.1%, 0.15%, 0.2%, 0.3% and 0.4% are synthesized by the wet chemical method. The polyvinyl alcohol (PVA)-capped ZnS thin film with 0.2% Cu concentration and various PVA concentrations are prepared by the spin-coating method. The microstructures of the samples are investigated by the X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The results show that the prepared samples belong to the wurtzite structure with the average particle size of about 3–7 nm. The optical properties of samples are studied by measuring absorption and photoluminescence (PL) spectra in the wavelength range from 300 nm to 900 nm at 300 K. It is shown that the luminescent intensity of ZnS : Cu nanopowders reaches the highest intensity for optimal Cu concentration of 0.2% with the corresponding values of its direct band gap estimated to be about 3.90 eV. While the PVA coating does not affect the microstructure of ZnS nanometerials, the PL spectra of the samples are found to be affected by the PVA concentration as well as the exciting power density. The influence of the polymer coating on the optical properties can be explained by the quantum confinement effect of ZnS nanoparticles in the PVA matrix.
Estimation of atmospheric CO
2
uptake by silicate weathering in the Himalayas and the Tibetan Plateau: a review of existing fluvial geochemical data
Authors: Huh Youngsook
Published: August 2010

The fluvial geochemical data of major rivers draining the Himalayas and the Tibetan Plateau (HTP) are compiled from literature and supplemented with data from the author's group to explore the spatial variability in the major element and strontium isotopic compositions and in rates of silicate weathering and concomitant drawdown of atmospheric CO
2
. The results indicate that carbonate weathering dominates the major element composition of these rivers, and when the silicate contributions are carefully separated, there is spatial variability within the HTP system. Silicate contributions are highest in the rivers of the Himalayan syntaxes and in the Yamuna, Alaknanda-Bhaghirathi and Kosi tributaries of the Ganges. The
87
Sr/
86
Sr ratios are especially radiogenic in the Ganges tributaries but the values do not necessarily correlate with the relative input from silicate weathering. Even in the Yamuna tributary of the Ganges where rates of CO
2
consumption by silicate weathering are several times those of the rivers of the eastern Tibetan Plateau, the rates are comparable to the rivers draining the Andes. Thus, the Ganges tributaries supply uniquely radiogenic
87
Sr to the ocean but cannot be considered anomalous in terms of silicate weathering rates in comparison to other major rivers draining orogenic zones.

Supplementary material:

Major element concentration and strontium isotope ratio data for Huh (unpublished) is available at
http://www.geolsoc.org.uk/SUP18408
.