967 research outputs found

    Algebraic surface grid generation in three-dimensional space

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    An interactive program for algebraic generation of structured surface grids in three dimensional space was developed on the IRIS4D series workstations. Interactive tools are available to ease construction of edge curves and surfaces in 3-D space. Addition, removal, or redistribution of points at arbitrary locations on a general 3-D surface or curve is possible. Also, redistribution of surface grid points may be accomplished through use of conventional surface splines or a method called 'surface constrained transfinite interpolation'. This method allows the user to redistribute the grid points on the edges of a surface patch; the effect of the redistribution is then propagated to the remainder of the surface through a transfinite interpolation procedure where the grid points will be constrained to lie on the surface. The program was written to be highly functional and easy to use. A host of utilities are available to ease the grid generation process. Generality of the program allows the creation of single and multizonal surface grids according to the user requirements. The program communicates with the user through popup menus, windows, and the mouse

    Generation of Surface Coordinates by Elliptic Partial Differential Equations

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    The problem of generating spatial coordinates by numerical methods through carefully selected mathematical models is of current interest both in mechanics and physics. The problem of generation of a desired system of coordinates in a given surface was considered, which essentially is an effort directed to the problem of grid generation in a two-dimensional non-Euclidean space. The mathematical model selected for this purpose is based on the formulae of Gauss for a surface. The proposed equations can be used to generate a new coordinate system from the data of an already given coordinate system in a surface. If the coefficients of the first and second fundamental forms have been given, then the proposed equations can be used to generate a surface satisfying the given data (surface fitting). The proposed equations can also be used to generate surfaces in the space between two arbitrary given surfaces, thus providing 3D grids in an Euclidean space

    User's guide to PMESH: A grid-generation program for single-rotation and counterrotation advanced turboprops

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    A detailed operating manual is presented for a grid generating program that produces 3-D meshes for advanced turboprops. The code uses both algebraic and elliptic partial differential equation methods to generate single rotation and counterrotation, H or C type meshes for the z - r planes and H type for the z - theta planes. The code allows easy specification of geometrical constraints (such as blade angle, location of bounding surfaces, etc.), mesh control parameters (point distribution near blades and nacelle, number of grid points desired, etc.), and it has good runtime diagnostics. An overview is provided of the mesh generation procedure, sample input dataset with detailed explanation of all input, and example meshes

    Aktivitas Penangkapan Radikal 2,2–Difenil–1–Pikrilhidrazil (DPPH) Oleh Ekstrak Metanol Paprika Merah (Capsicum annuum, L.)

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    Paprika merah (Capsicum annum L.) banyak mengandung β–karoten  (provitamin A), likopen, vitamin E serta vitamin C telah diuji aktivitasnya sebagai penangkap radikal 2,2–difenil–1–pikrilhidrazil (DPPH). Sampel diekstraksi dengan cara maserasi menggunakan metanol. Ekstrak yang diperoleh dilakukan analisis aktivitas antioksidannya secara kualitatif dengan larutan DPPH 0,4 mM dan reagen ferri tiosianat. Identifikasi terhadap senyawa yang berpotensi sebagai antioksidan dilakukan dengan spektrofotometer UV–Vis. Aktivitas penangkapan radikal DPPH oleh ekstrak metanol paprika merah ditetapkan secara spektrofotometri pada panjang gelombang 517 nm. Dari hasil analisis diperoleh nilai IC50 paprika merahsebesar0,299 ± 4,98x10-3 mg/mL. Aktivitas paprika merah sebagai penangkap radikal DPPH  kurang poten dibandingkan dengan β–karoten (IC50 0,066 ± 3,24x10-3 mg/mL). Kata kunci : antioksidan, paprika merah, Capsicum annuum, DPP

    Antioxidant activity of methanolic extract from yellow paprika (Capsicum annuum, L.) by DPPH radical scavenging method

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    Yellow paprika (Capsicum annuumL.) is one of fruit that contains of carotenoid compounds as an antioxidant. This reasearch was aimed to know an antioxidant capacity of methanolic extract from yellow paprika with 2,2–diphenyl–1–picrylhydrazyl (DPPH) radical scavenging method. The fresh yellow paprika was determined of its loss of drying by gravimetric. The yellow paprika extract was obtained by maceration using methanol as solvent. The content of β–carotene from this extract was analyzed qualitively by thin layer chromatography and UV-Vis spectrophotometer. The antioxidant activity of methanolic extract from yellow paprika was determined base on measurement of residual DPPH by UV–Vis spectrophothometric at wavelength of 515.6 nm. The data was used to calculate % inhibition. Furthermore, IC50 value was determined to know potency of its antioxidant. The result of loss of drying yellow paprika fruit was obtained 6.33 ± 0.02 %. The analysis with thin layer chromatography and UV-Vis spectrophotometer showed that this fruit was contain of β–carotene. The result of antioxidant activity analysis from yellow paprika fruit was obtained IC50 value of 0.3028 ± 0.0093 mg/mL. The result of the research showed that the antioxidant potency of yellow paprika was less than β–carotene (IC50 0.0852 ± 0.0009 mg/mL)

    Secure communication over fully quantum Gel'fand-Pinsker wiretap channel

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    In this work we study the problem of secure communication over a fully quantum Gel'fand-Pinsker channel. The best known achievability rate for this channel model in the classical case was proven by Goldfeld, Cuff and Permuter in [Goldfeld, Cuff, Permuter, 2016]. We generalize the result of [Goldfeld, Cuff, Permuter, 2016]. One key feature of the results obtained in this work is that all the bounds obtained are in terms of error exponent. We obtain our achievability result via the technique of simultaneous pinching. This in turn allows us to show the existence of a simultaneous decoder. Further, to obtain our encoding technique and to prove the security feature of our coding scheme we prove a bivariate classical-quantum channel resolvability lemma and a conditional classical-quantum channel resolvability lemma. As a by product of the achievability result obtained in this work, we also obtain an achievable rate for a fully quantum Gel'fand-Pinsker channel in the absence of Eve. The form of this achievable rate matches with its classical counterpart. The Gel'fand-Pinsker channel model had earlier only been studied for the classical-quantum case and in the case where Alice (the sender) and Bob (the receiver) have shared entanglement between them.Comment: version 2, 1 figure, 26 pages, added some extra proof and corrected few typo
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