High Rydberg state carbon recombination lines toward Cassiopeia A: 332 MHz VLA observations and comparison with H I and molecular lines

We present observations of the C270alpha carbon recombination line, 21 cm neutral hydrogen line and (CO)-C-12 (J = 1 --> 0) molecular line toward Cas A. A comparison of the distribution of recombination line optical depths over the face of Cas A with that of H I optical depths and molecular line emission favors the association of C270alpha regions with H I rather than molecular clouds. The association makes it possible to self-consistently determine several physical parameters of the clouds by combining the recombination line and 21 cm H I measurements.

Structure of Ethyl 5-Methoxy-3-phenyl-2-indolecarboxylate

C18H17NO3, M r = 295"34, monoclinic, C2/c, a = 11.689 (2), b = 22.934 (4), c = 11.592 (2) A, fl=100.16(3) ° , V =3058.8(8) A 3, Z=8, D,n= 1.30 (5), Dx = 1.28 Mg m -3, A(Mo Ka) = 0.7107 A, tz(Mo Ka) = 0.094 mm- 1, F(000) = 1248, T = 300 K, final R = 0.046 for 1849 observed reflections [I > 30"(/)]. The indole nucleus is slightly bent along the C(8)---C(9) bond. The phenyl ring connected to the indole moiety is rotated about the C(3)---C(10) bond by 45.8 (3) °. The carboxyl group makes a dihedral angle of 8.1 (4) ° with the mean plane of the indole moiety. Centrosymmetrically related pairs of molecules are linked through hydrogen bonds across the centre of symmetry and form dimers.

Electrochemical Detection of Bisphenol A Using Graphene-Modified Glassy Carbon Electrode

Graphene's nano-dimensional nature and excellent electron transfer properties underlie its electrocatalytic behavior towards certain substances. In this light, we have used graphene in the electrochemical detection of bisphenol A. Graphene sheets were produced via soft chemistry route involving graphite oxidation and chemical reduction. X-ray diffraction, Fourier transform infra-red (FT-IR) and Raman spectroscopy were used for the characterization of the as-synthesized graphene. Graphene exhibited amorphous structure in comparison with pristine graphite from XRD spectra. FTIR showed that graphene exhibits OH and COOH groups due to incomplete reduction. Raman spectroscopy revealed that multi-layered graphene was produced due to low intensity of the 2D-peak. Glassy carbon electrode was modified with graphene by a simple drop and dry method. Cyclic voltammetry was used to study the electrochemical properties of the prepared graphene-modified glassy carbon electrode using potassium ferricyanide as a redox probe. The prepared graphene- modified glassy carbon electrode exhibited more facile electron kinetics and enhanced current of about 75% when compared to the unmodified glassy carbon electrode. The modified electrode was used for the detection of bisphenol A. Under the optimum conditions, the oxidation peak current of bisphenol A varied linearly with concentration over a wide range of 5 x 10(-8) mol L-1 to 1 x 10(-6) mol L-1 and the detection limit of this method was as low as 4.689 x 10(-8) M. This method was also employed to determine bisphenol A in a real sample

Shape-function-relationship (SFR) framework for semantic interoperability of product model

The problem of semantic interoperability arises while integrating applications in different task domains across the product life cycle. A new shape-function-relationship (SFR) framework is proposed as a taxonomy based on which an ontology is developed. Ontology based on the SFR framework, that captures explicit definition of terminology and knowledge relationships in terms of shape, function and relationship descriptors, offers an attractive approach for solving semantic interoperability issue. Since all instances of terms are based on single taxonomy with a formal classification, mapping of terms requires a simple check on the attributes used in the classification. As a preliminary study, the framework is used to develop ontology of terms used in the aero-engine domain and the ontology is used to resolve the semantic interoperability problem in the integration of design and maintenance. Since the framework allows a single term to have multiple classifications, handling context dependent usage of terms becomes possible. Automating the classification of terms and establishing the completeness of the classification scheme are being addressed presently.

Volume conservation issues in incompressible smoothed particle hydrodynamics

A divergence-free velocity field is usually sought in numerical simulations of incompressible fluids. We show that the particle methods that compute a divergence-free velocity field to achieve incompressibility suffer from a volume conservation issue when a finite time-step position update scheme is used. Further, we propose a deformation gradient based approach to arrive at a velocity field that reduces the volume conservation issues in free surface flows and maintains density uniformity in internal flows while retaining the simplicity of first order time updates. (C) 2015 Elsevier Inc. All rights reserved.

初始镀铬层微裂纹形貌的基体化学腐蚀法研究

通过基体化学腐蚀法去掉钢基体,利用高分辨扫描电镜(HRSEM)就钢基体激光离散淬火对初始镀铬层界面微裂纹形貌影响进行研究.结果表明:激光处理的裂纹宽度近似是原始基体的一半;在离散处理的钢基体上镀铬可以在原始基体上形成一条与激光扫描方向相一致的宽裂纹.

Prevalencia de Cysticercus bovis en la carne procedente de dos mataderos industriales de ganado bovino

En el presente trabajo se analizó la situación existente con respecto a la cysticercosis bovina, en las empresas: San Martín, ubicada en el km 67 1/2, carretera panamericana, (Nandaime) y Alfonso González P. ubicada en el Km 16 1/2 carretera nueva a León, (Los Brasiles) siendo únicamente para consumo local. Con los datos recabados se evaluaron los porcentajes de infestación de los años 1987, 1988, 1989, 1990, 1991 para el matadero San Martín y 1989, 1990, 1991 para el matadero Alfonso González P., además se determinó la infestación por categorías para ambos mataderos, el departamento con mayor prevalencia en ambos mataderos y las pérdidas económicas, en ambas empresas. El análisis estadístico fue el de Ji- cuadrado (X 2) para lo cual se usó el procedimiento catmod del paquete statistical analysis system. (SAS). Los resultados obtenidos en el análisis de varianza, demuestran que existe diferencias significativa entre mataderos y a 10 largo de los años con un nivel de significancia de (p<0.05) obteniéndose 1.90% de infestación global para los años en estudio, siendo para et matadero San Martín 2.78% de infestación y para el matadero Alfonso González P. 1.12% de infestación, así como existe diferencia significativa para las diferentes categorías (p<0.05), siendo la categoría vaca (CJ) la más afectada para el matadero. San Martín y en el matadero Alfonso González P. la categoría toro (C2); Rivas resultó ser el departamento con el mayor número de animales parasitados seguido de Boaco, Chontales y Granada para el matadero San Martín y para el matadero Alfonso González P., Megasa resultó ser quien obtuvo el mayor número de animales parasitados seguido por la Subasta, Chontales y Matagalpa. Las pérdidas económicas revelan cifras aproximadas de U $ 283,932 para los productores en ambos mataderos, adicionando a esto las divisas no captadas de U$ 689,144.34 por disminución de las exportaciones.

Asymptotic analysis of plane-strain mode I steady-state crack growth in transformation toughening ceramics (II)

Based on a constitutive law which includes the shear components of transformation plasticity, the asymptotic solutions to near-tip fields of plane-strain mode I steadity propagating cracks in transformed ceramics are obtained for the case of linear isotropic hardening. The stress singularity, the distributions of stresses and velocities at the crack tip are determined for various material parameters. The factors influencing the near-tip fields are discussed in detail.

Centrifugal experimental study of suction bucket foundations under dynamic loading

Centrifugal experiments were carried out to investigate the responses of suction bucket foundations under horizontal and vertical dynamic loading. It is shown that when the loading amplitude is over a critical value, the sand at the upper part around the bucket is softened or even liquefied. The excess pore pressure decreases from the upper part to the lower part of the sand layer in the vertical direction and decreases radially from the bucket's side wall in the horizontal direction. Large settlements of the bucket and the sand layer around the bucket are induced by dynamic loading. The dynamic responses of the bucket with smaller height (the same diameter) are heavier.

Microstructure and mechanical properties of Zr-Cu-Al bulk metallic glasses

Zr49Cu46Al5 and Zr48.5Cu46.5Al5 bulk metallic glasses(BMGs) with diameter of 5 mm were prepared through water-cooled copper mold casting. The phase structures of the two alloys were identified by X-ray diffractometry(XRD). The thermal stability was examined by differential scanning calorimetry(DSC). Zr49Cu46Al5 alloy shows a glass transition temperature, T, of about 689 K, an crystallization temperature, T-x, of about 736 K. The Zr48.5Cu46.5Al5 alloy shows no obvious exothermic peak. The microstructure of the as-cast alloys was analyzed by transmission electron microscopy(TEM). The aggregations of CuZr and CuZr2 nanocrystals with grain size of about 20 nm are observed in Zr49Cu46Al5 nanocrystalline composite, while the Zr48.5Cu46.5Al5 alloy containing many CuZr martensite plates is crystallized seriously. Mechanical properties of bulk Zr49Cu46Al5 nanocrystalline composite and Zr48.5Cu46.5Al5 alloy measured by compression tests at room temperature show that the work hardening ability of Zr48.5Cu46.5Al5 alloy is larger than that of Zr48.5Cu46.5Al5 alloy.

CSM玻璃钢复合型断裂的有限元分析

对切短玻璃纤维毡增强聚脂层板的复合型断裂进行了有限元分析。采用八节点四边形等参元的正规型式计算应力分布与损伤区扩展;而用坍塌(collapsed)三角形四分之一点(quarter-point)奇异元计算应力强度因子K_Ⅰ与K_Ⅱ。 用节点位移约束与释放技术计算了裂纹扩展过程。对决定应力强度因子K_Ⅰ与K_Ⅱ的三种方法进行了对比。对施加于裂纹顶点节点约束条件的影响进行了评价。最后基于实验测得的断裂载荷与临界裂纹长度,估算了材料在这种受力条件下的复合型临界应力强度因子K_(ⅠC)和K_(ⅡC)。

Optimization of tried wave-function in quantum monte-carlo method

A method for optimizing tried wave functions in quantum Monte Carlo method has been found and used to calculate the energies of molecules, such as H-2, Li-2, H-3+, H-3 and H-4. Good results were obtained.