Tangential Angle Research Articles

On the existence of solutions to geometrically nonlinear problems for shallow Timoshenko-type shells with free edges

In the paper we investigate the solvability of the boundary-value problems for shallow isotropic elastic shells within the framework of Timoshenko’s shearmodel. The considered problems are nonlinear geometrically and linear physically. The method of studying consists in reducing the initial system of equilibrium equations to one nonlinear differential equation with respect to deflections. In doing so integral representations for the tangential displacements and angles of rotation play a significant role. The representations are deduced by making use of general solutions to the inhomogeneous Cauchy-Riemann equation. The solvability is established by the principle of contracting mappings.

IR thermography diagnostics for the WEST project

To operate long plasma discharge in tokamak equipped with actively cooled plasma facing components (PFC), infrared (IR) thermography is a key diagnostic. Indeed IR data are used for both PFC safety monitoring, to avoid material degradation and water leak, and various physics studies on plasma-wall interaction. The IR monitoring is becoming even more crucial with today metallic PFCs. This is the case for the WEST project (Tungsten (W) Environment for Steady State Tokamak), which aims at installing a W divertor in Tore Supra (TS), in order to operate the 1st tokamak with a full W actively cooled divertor in long plasma discharges.The IR thermography system for the WEST project described in this paper will consist of a set of 3 different diagnostics: (1) Six cameras located in upper ports viewing the full W divertor, which reuse a part of the existing diagnostic of TS. (2) Five novel views located behind the inner protection panels for the antennas monitoring, based on an innovative imaging fibers bundle technology. (3) A tangential wide angle view located in a median port, for the upper divertor and first wall monitoring.

Fitting a Bandlimited Curve to Points in a Plane

We describe an algorithm for the reparametrization of a closed curve defined by a sequence of $m$ points while providing the user a high level of control over the frequency content of the resulting curve. Specifically, the algorithm views the tangential angle of the curve as a function of the arc-length, filters it as such, and adds a small analytic perturbation so that the curve passes through the input data. If the number of nodes in the initial discretization is $n$, the entire scheme has asymptotic complexity $\mathcal{O}(n\log n)$. The resulting curve is analytic and bandlimited. The performance of the scheme is illustrated with several numerical examples.

Signs of the Times: The Brontës and Contemporary Society

A treatise on Chartism might seem to open a narrow window on the lives and works of the Brontes. At best we could hope to find a tangential angle on one novel — Shirley — which, ironically, is know...

The coupling between the solar wind and proton fluxes at GEO

Abstract. The relationship between the solar wind and the proton flux at geosynchronous Earth orbit (GEO) is investigated using the error reduction ratio (ERR) analysis. The ERR analysis is able to search for the most appropriate inputs that control the evolution of the system. This approach is a black box method and is able to derive a mathematical model of a system from input-output data. This method is used to analyse eight energy ranges of the proton flux at GEO from 80 keV to 14.5 MeV. The inputs to the algorithm were solar wind velocity, density and pressure; the Dst index; the solar energetic proton (SEP) flux; and a function of the interplanetary magnetic field (IMF) tangential magnitude and clock angle. The results show that for lowest five energy channels (80 to 800 keV) the GEO proton fluxes are controlled by the solar wind velocity with a lag of two to three days. However, above 350 keV, the SEP fluxes, accounts for a significant portion of the GEO proton flux variance. For the highest three energy channels (0.74 to 14.5 MeV), the SEPs account for the majority of the ERR. The results also show an anisotropy of protons with gyrocenters inside GEO and outside GEO, where the protons inside GEO are controlled partly by the Dst index and also an IMF-clock angle function.

Role of gaseous film cooling injector orientation in duct flow: Experimental Study

Experimental investigations are carried out to analyze the effect of coolant injector configuration on overall film cooling performance in a cylindrical test section similar to a rocket combustion chamber. Three different injector orientations are investigated: (i) holes parallel to core gas flow, (ii) holes at a tangential angle to the core gas flow, and (iii) compound angle holes inclined to the wall both in the tangential and azimuthal direction. The objective is to provide a consistent set of measurements for cooling effectiveness within the same test facility with respect to different blowing ratios ranging from 1.69 to 3.9. The results suggest that coolant injection parallel to the axis should be used in situations where far field effectiveness is of concern. The tangential injection, in general, shows lower wall protection compared to other schemes. The results show that the compound angle configuration augments film cooling effectiveness in the near injection regimes. However comparison of the effectiveness values for the compound injectors suggests the existence of an optimum compound angle configuration. The circumferential wall temperature data represent systematic changes in the coolant flow behavior with the change from straight injection to compound angle injection.

Contour Based Retrieval for Plant Species

Recognizing a p lant in any huge vegetation is a tedious work for us. We recognize a plant on the basis of its size, leaves, flowers, fru its, etc. Leaf is a part of the p lant wh ich can be found on plants almost in all seasons and most of the time we have to recognize plants on the basis of its leaf. But when dealing with leaf o f plant, it is important to consider the finer details of the contour representing the shape of the leaf. We are t rying to build a system which has a database of leaves of different plants and given a leaf, we find out the plant to which it may belong. In this paper, we present the results of tangential angle approach used for retrieval. A database of around one thousand leaves of different plants has been created. Each leaf image is preprocessed to extract its boundary. Then tangential angle approach is applied wh ich captures the angular details of the boundary of shape. We have done the testing for around 1000 leaves and on the basis of that recall, precision and error rate have been calculated to measure the effectiveness of the proposed method.

비선형 암석 파괴조건식의 접선 마찰각과 점착력의 중간주응력 의존성

Although Mohr-Coulomb failure criterion has limitations in that it is a linear criterion and the effect of the intermediate principal stress on failure is ignored, this criterion has been widely accepted in rock mechanics design. In order to overcome these shortcomings, the Hoek-Brown failure criterion was introduced and recently a number of 3-D failure criteria incorporating the effect of the intermediate principal stress on failure have been proposed. However, in many rock mechanics designs, the possible failure of rock mass is still evaluated based on Mohr-Coulomb criterion and most of practitioners are accustomed to understanding the strength of rock mass in terms of the internal friction angle and cohesion. Therefore, if the equivalent Mohr-Coulomb strength parameters of the advanced failure criteria are calculated, it is possible to take advantage of the advanced failure criteria in the framework of the Mohr-Coulomb criterion. In this study, a method expressing the tangential Mohr-Coulomb strength parameters in terms of the stress invariant is proposed and it is applied to the generalized Hoek-Brown criterion and the HB-WW criterion. In addition, a new approach describing the geometric meaning of the -dependency of failure criteria in 3-D principal stress space is proposed. Implementation examples of the proposed method show that the influence of the intermediate principal stress on the tangential friction angle and cohesion of the HB-WW criterion is considerable, which is not the case for the 2-D failure criterion.

The Effect of Tangential Swirl Angle on NOX Formation in a Non-Premixed LPG/Air Flame

In the present study the effect of tangential swirl angle on NOx formation in non premixed liquefied petro gas (LPG) – air flame is examined. The liquefied petrol gas used (LPG) contains of 50% Propane and 50% Butane. A new injection swirl ratio has been introduced for the new Circumferential Arranged Air and Fuel Burner (CAFB) burner namely the injection swirl number (ISN), ISN = tan θ, where θ is the injection angle. The injection swirl number (ISN) used is 0, 0.27, 0.57, 1 and 1.73 which corresponding to the injection angles 0, 15, 30, 45 and 60 degree respectively. An empirical correlation has been derived for the new CAFB burner flame length as a function of the new derived (ISN). The experiments are conducted in an ax symmetric cylindrical combustion chamber for a range of equivalence ratio and swirl angle. The numerical simulations are carried out with the CFD code, Fluent Ansys 6.3. The turbulence k-e model is employed. Both predictions and experiments show that as the swirl number increase, the temperature and the thermal NOx first slightly increase and then strongly decrease at the exit of the combustion chamber. An empirical correlation has been derived for the new CAFB burner. Numerical simulations by Fluent Ansys 6.3 were able to obtain reasonable agreement with the experimental results.

A Numerical Study of Cubic Parabolas on Railway Transition Curves

This paper mainly focuses on the design of transition curves of the cubic parabola type in track alignment design. Equations for the transition curves are first derived from the theory of cubic parabolas using calculus techniques. They are then analyzed using numerical analysis methods. The proposed formulation is evaluated by comparison of its calculated results with data in 684 actual cases of transition curves. The accuracy of the proposed method is verified in this study by comparing the estimated results with collected data from actual engineering projects, and the applicability of the new method to the engineering practice of track alignment design is justified. The chainage and coordinates of the control points as well as other curve points and the tangential angle can be easily calculated using the transition curve equations.

가스터빈 연소기의 연소장 해석을 위한 스월 예혼합 버너의 수치적 모델링에 관한 연구

swirler 채택하여 복잡한 형상의 발전용 가스터빈 연소기의 효율적인 수치해석이 타당할 것으로 판단된다. Abstract: The flow and combustion characteristics in a premixed swirl combustor with a double cone burner are numerically analyzed to adopt a swirler model. The internal recirculation zone formed at the burner exit can be realized by a swirler with inner and outer diameters of 56 and 152 mm, respectively, and accordingly, the flow rate and radial velocity were determined. To select the tangential velocity, swirl and recirculation angles are introduced. A tangential velocity of 40 m/s produces an internal recirculation zone similar to that in a combustor. At the liner exit, the errors in temperature and velocity are 2.8% and 0%, respectively, and they are negligibly small. However, NOx emissions are underestimated by 67% in the numerical results obtained using the swirler model. Although considerable quantitative errors are induced by the swirler model, it can be useful numerical model for the EV burner because it can approximately simulate the essential flow and combustion characteristics in a premixed swirl combustor with a double cone burner and it is expected to make combustion analysis efficient in a gas turbine combustor with complex geometries.

Sensitivity analysis of fracture scattering

We use 2D and 3D finite-difference modeling to numerically calculate the seismic response of a single finite fracture with a linear-slip boundary in a homogeneous elastic medium. We use a point explosive source and ignore the free surface effect, so the fracture scattered wavefield contains two parts: P-to-P scattering and P-to-S scattering. The elastic response of the fracture is described by the fracture compliance. We vary the incident angle and fracture compliance within a range considered appropriate for field observations and investigate the P-to-P and P-to-S scattering patterns of a single fracture. P-to-P and P-to-S fracture scattering patterns are sensitive to the ratio of normal to tangential fracture compliance and incident angle, whereas the scattering amplitude is proportional to the compliance, which agrees with the Born scattering analysis. We find that, for a vertical fracture, if the source is located at the surface, most of the energy scattered by the fracture propagates downwards. We also study the effect of fracture height on the scattering pattern and scattering amplitude.

Endoscopic band ligation: Beyond prevention and management of gastroesophageal varices

Endoscopic band ligation (EBL) is the preferred endoscopic technique for the endoscopic treatment of acute esophageal variceal bleeding. EBL has also been used to treat nonvariceal bleeding. Recently, Han et al demonstrated that EBL can be a feasible and safe alternate technique for the management of iatrogenic gastric perforation especially in cases in which closure with endoclips is difficult. EBL is technically simpler to perform than other methods and provides a good view of the lesions under direct pressure and suction from the transparent ligation cap. EBL can be used even if the diameter of the perforation is greater than 10 mm or if there is a severe tangential angle. In this commentary, we discuss the efficacy and safety of EBL for the closure of iatrogenic gastrointestinal perforation. We also discuss the advantages and disadvantages of EBL for the treatment of nonvariceal bleeding.

Driving Control of Car-Like Robots by Path-Generating Regulator

Autonomous four-wheeled robots have been widely studied and developed for various purposes over several decades. We have developed an All Terrain Vehicle(ATV)-based, four-wheeled, car-like robot to support the environmental field survey of landfills. Navigating the robot toward an observation spot must have feedback control of the vehicle. We propose a path-generating regulator (PGR) for car-like robots and show the properties of its control performance. Originally, the PGR was a control method for two-wheeled mobile robots to converge at the origin of a coordinate frame, of which the heading angle is controlled so as to align the tangential angle of one of the path among the path function group. Unlike other control methods of the nonholonomic system, neither a coordinate transformation nor an input transformation is needed in this method. In this paper, the PGR is extended to car-like robots. We take care of the singular points, due to both of the mechanism of a car-like robot and the control method. First we show that the origin of the control system is stable in the sense of Lyapunov in accordance with Lyapunov's theory. Next, we discuss initial state convergence at the origin. We examine the performance of the control method via simulations, and apply the method to the ATV-based, car-like robot. As a result, we show the property of convergence to the origin in the car-like robot using the proposed control method.

응력불변량으로 표현한 일반화된 Hoek-Brown 파괴조건식의 등가 마찰각 및 점착력

Implementing the generalized Hoek-Brown failure criterion in the framework of the Mohr-Coulomb criterion requires the calculation of the equivalent friction angle and cohesion. In the conventional method based on the Balmer (1952)'s theory, the tangential instantaneous friction angle and cohesion are expressed in terms of the minimum principal stress   , which does not provide the information about the dependency of the equivalent parameters on the hydrostatic pressure and the stress path. In this study, this defect of the conventional method has been overcome by representing the equivalent parameters in terms of stress invariants. Through the example implementation of the new method, the influence of the magnitude of the hydrostatic pressure and the Lode angle on the tangential instantaneous friction angle and cohesion is investigated. It turns out that the tangential instantaneous friction angle is maximum when the stress condition is triaxial extension, while the tangential cohesion is maximum when the stress condition is triaxial compression. The dependency of the equivalent Mohr-Coulomb strength parameters on the hydrostatic pressure and the Lode angle tends to be more substantial for the favorable rockmass of larger GSI value.

Computational Study on Influence of Water Injection Angle to Aluminum/Water Reaction Motor

In Aluminum/Water Reaction Motor chamber, water injection angle plays an important role on mixture of aluminum particle fuel and water droplets and can affect motor performance further. On the basis of FLUENT software and taking phase transition and reaction between water droplets and aluminum particles into account, numerically simulated cases of different water injection angles by Particle Stochastic Trajectory Model. Computed total evaporation rate of water droplets, reaction rate of aluminum particles and specific impulse for the motor. Furthermore judged injection angle effect from these parameters. By comparison and analysis, it is found that hybrid injection case could get best multi-phase mixture effect and specific impulse performance for the motor. Namely axial injection angle with 45°in the main chamber and tangential injection angle with 60°in the afterburning chamber is the best case. The conclusion could provide a new idea for motor working process design.

Operational performance of inlet barrier filters for rotorcraft

AbstractThis contribution addresses the subject of engine inlet barrier filters (IBF) for rotorcraft. The purpose of an IBF is to mitigate the risk of particle ingestion by the engine, a situation that can cause irrevocable damage to key components. The risk is significantly elevated during a brownout landing, in which the rotor wake of a descending helicopter interacts with loose ground sediment, causing the generation of a dust cloud. In such a condition, an IBF successfully removes particles from the engine-bound air at the expense of a pressure drop, which grows temporally. The increase in pressure drop is caused by but not limited to an increase in incident velocity and a decrease of mean particle size; however the rate may be slowed by operating the filter at a tangential angle to the flow. The current work presents findings of a parametric study into the factors affecting particle accumulation and the consequential loss of inlet total pressure.

Tangential x-ray imaging crystal spectrometer on J-TEXT tokamak

A tangential x-ray imaging crystal spectrometer (XICS) has been developed for the J-TEXT tokamak to measure the ion temperature and the plasma toroidal rotation velocity. The resonance spectral line and its satellites of Ar XVII in the ranges of 3.94 Å-4.0 Å are detected. A spherically bent quartz crystal with 2d = 4.913 Å is used in this system. The crystal has a dimension of 9 cm high and 3 cm wide and the radius of curvature 3823 mm. The XICS is designed to receive emission of Ar XVII from -10 cm to +10 cm region with a spatial resolution of 3.1 cm in the vertical direction considering the parameters of the J-TEXT plasma. The XICS has a tangential angle of 27° with respect to toroidal direction in the magnetic axis. A two-dimensional 100 mm by 300 mm multi-wire proportional counter is applied to detect the spectra.

Numerical Simulation for the Optimization of the Angle of the Velocity of the Hydrogen in the High Performance Hydrogen Bell-Type Annealers

The flow of the hydrogen has played an important role in the heat exchange in the inner bell. In this research, we have studied the volume distribution of the hydrogen in the inner bell through numerical simulation method, and we get the volume distribution law of the hydrogen when we change the axial angle and the tangential angle of the velocity of the hydrogen flowing into the inner bell while we do not change the speed of the hydrogen. This research could provide theory reference for the design and application of the structure of the coil base of the high performance hydrogen bell-type annealers later.

Computational and qualitative aspects of motion of plane curves with a curvature adjusted tangential velocity

In this paper, we investigate a time‐dependent family of plane closed Jordan curves evolving in the normal direction with a velocity that is assumed to be a function of the curvature, tangential angle, and position vector of a curve. We follow the direct approach and analyze the system of governing PDEs for relevant geometric quantities. We focus on a class of the so‐called curvature adjusted tangential velocities for computation of the curvature driven flow of plane closed curves. Such a curvature adjusted tangential velocity depends on the modulus of the curvature and its curve average. Using the theory of abstract parabolic equations, we prove local existence, uniqueness, and continuation of classical solutions to the system of governing equations. We furthermore analyze geometric flows for which normal velocity may depend on global curve quantities such as the length, enclosed area, or total elastic energy of a curve. We also propose a stable numerical approximation scheme on the basis of the flowing finite volume method. Several computational examples of various nonlocal geometric flows are also presented in this paper. Copyright © 2012 John Wiley & Sons, Ltd.