THREE-LAYER FLUID FLOW OVER A SMALL OBSTRUCTION ON THE BOTTOM OF A CHANNEL

Many boundary value problems occur in a natural way while studying fluid flow problems in a channel. The solutions of two such boundary value problems are obtained and analysed in the context of flow problems involving three layers of fluids of different constant densities in a channel, associated with an impermeable bottom that has a small undulation. The top surface of the channel is either bounded by a rigid lid or free to the atmosphere. The fluid in each layer is assumed to be inviscid and incompressible, and the flow is irrotational and two-dimensional. Only waves that are stationary with respect to the bottom profile are considered in this paper. The effect of surface tension is neglected. In the process of obtaining solutions for both the problems, regular perturbation analysis along with a Fourier transform technique is employed to derive the first-order corrections of some important physical quantities. Two types of bottom topography, such as concave and convex, are considered to derive the profiles of the interfaces. We observe that the profiles are oscillatory in nature, representing waves of variable amplitude with distinct wave numbers propagating downstream and with no wave upstream. The observations are presented in tabular and graphical forms.

Phase-field elasticity model based on mechanical jump conditions

Computational models based on the phase-field method typically operate on a mesoscopic length scale and resolve structural changes of the material and furthermore provide valuable information about microstructure and mechanical property relations. An accurate calculation of the stresses and mechanical energy at the transition region is therefore indispensable. We derive a quantitative phase-field elasticity model based on force balance and Hadamard jump conditions at the interface. Comparing the simulated stress profiles calculated with Voigt/Taylor (Annalen der Physik 274(12):573, 1889), Reuss/Sachs (Z Angew Math Mech 9:49, 1929) and the proposed model with the theoretically predicted stress fields in a plate with a round inclusion under hydrostatic tension, we show the quantitative characteristics of the model. In order to validate the elastic contribution to the driving force for phase transition, we demonstrate the absence of excess energy, calculated by Durga et al. (Model Simul Mater Sci Eng 21(5):055018, 2013), in a one-dimensional equilibrium condition of serial and parallel material chains. To validate the driving force for systems with curved transition regions, we relate simulations to the Gibbs-Thompson equilibrium condition

Thermoelectric properties of Co substituted synthetic tetrahedrite

Transition metal atom (Co) substituted synthetic tetrahedrite compounds Cu12-xCoxSb4S13 (x = 0, 0.5, 1.0, 1.5, 2.0) were prepared by solid state synthesis. X-Ray Diffraction (XRD) patterns revealed tetrahedrite as the main phase, whereas for the compounds with x = 0, 0.5 a trace of impurity phase Cu3SbS4 was observed. The surface morphology showed a large grain size with low porosity, which indicated appropriate compaction for the hot pressed samples. The phase purity, as monitored by Electron Probe Micro Analysis (EPMA) is in good agreement with the XRD data. The elemental composition for all the compounds almost matched with the nominal composition. The X-ray Photoelectron Spectroscopy (XPS) data showed that Cu existed in both +1 and +2 states, while Sb exhibited +3 oxidation states. Elastic modulus and hardness showed a systematic variation with increasing Co content. The electrical resistivity and Seebeck coefficient increased with increase in the doping content due to the decrease in the number of carriers caused by the substitution of Co2+ on the Cu1+ site. The positive Seebeck coefficient for all samples indicates that the dominant carriers are holes. A combined effect of resistivity and Seebeck coefficient leads to the maximum power factor of 1.76 mW m(-1) K-2 at 673 K for Cu11.5Co0.5Sb4S13. This could be due to the optimization in the carrier concentration by the partial substitution of Co2+ on both the Cu1+ as well as Cu2+ site at the same doping levels, which is also supported by the XPS data. The total thermal conductivity systematically decreased with increase of doping content as it is mainly influenced by the decrease of carrier thermal conductivity. The maximum thermoelectric figure of merit zT = 0.98 was obtained at 673 K for Cu11.5Co0.5Sb4S13. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

MPTP activates ASK1-p38 MAPK signaling pathway through TNF-dependent Trx1 oxidation in parkinsonism mouse model

Activation of apoptosis signal regulating kinase 1 (ASK1)-p38 MAPK death signaling cascade is irn plicated in the death of dopaminergic neurons in substantia nigra in Parkinson's disease (PD). We investigated upstream activators of ASK1 using an MPTP mouse model of parkinsonism and assessed the temporal cascade of death signaling in ventral midbrain (VMB) and striatum (ST). MPTP selectively activated ASK1 and downstream 1)38 MAPK in a time dependent manner in VMB alone. This occurred through selective protein thiol oxidation of the redox-sensitive thiol disulfide oxidoreductase, thiorcdoxin (Trxl), resulting in release of its inhibitory association with ASK1, while glutathione-S-transferase ji 1 (GSTM1) remained in reduced form in association with ASK1. Levels of tumor necrosis factor (TNF), a known activator of ASK1, increased early after MPTP in VMB. Protein ovariation netvvork analysis (PCNA) using protein states as nodes revealed TNF to be an important node regulating the ASK1 signaling cascade. In confirmation, blocking MPTP-mecliated TNF signaling through intrathecal administration of TNFneutralizing antibody prevented Trxl oxidation and downstream ASK1-p38 MAPK activation. Averting an early increase in TNF, which leads to protein thiol oxidation resulting in activation of ASK1-p38 signaling, may be critical for neuroprotection in PD. Importantly, network analysis can help in understanding the cause/effect relationship within protein networks in complex disease states. (C) 2015 Published by Elsevier Inc.

Sulfurization of sputtered Ag-In precursors for AgInS2 solar cell absorber layers

Silver indium sulfide (AgInS2) thin films are deposited by sequential sputtering of metallic precursor Ag/In] followed by sulfurization. Effect of substrate temperature (Tsub) during sulfurization process on the film growth is studied by varying the substrate temperature from 350 to 500 degrees C. Films prepared above 350 degrees C showed a mixture of orthorhombic and tetragonal phases of AgInS2 with tetragonal phase being dominant. Better crystalline, nearly stoichiometric and p-type films are obtained at a substrate temperature of 500 degrees C. The characteristic A(1) mode of AgInS2 chalcopyrite structure is observed in the Raman spectra at 274 cm(-1) for the films prepared above 350 degrees C. The grain size of the film increases from 489 to 895 nm with the increase in substrate temperature. The binding energies of the constituent elements are determined using XPS. The band gap of AgInS2 films is in the range of 1.64-1.92 eV and the absorption coefficient is found to be >10(4) cm(-1). Preliminary studies on the AgInS2/ZnS solar cell showed an efficiency of 0.3%. (C) 2015 Elsevier B.V. All rights reserved.

Photocytotoxic luminescent lanthanide complexes of DTPA-bisamide using quinoline as photosensitizer

Lanthanide complexes Ln(DTPAAQ)(DMF)] (1-3) (Ln - Pr (1), Eu (2), Tb (3), H(3)DTPAAQ - N, N `'-bis(3-amidoquinolyl) diethylenetriamine-N, N', N `'-triacetic acid, DMF - N, N-dimethylformamide) were studied for their structures, photophysical properties, DNA and protein binding, DNA photocleavage, photocytotoxicity and cellular internalization. The crystal structures of complexes Ln(DTPAAQ)(DMF)] (1-3) display a discrete mononuclear nine-coordinate {LnN(3)O(6)} tricapped-trigonal prism (TTP) coordination geometry. The europium and terbium complexes show strong luminescence properties in the visible region having a long luminescence lifetime (tau = 0.51-0.64 ms). The conjugated 3-aminoquinoline moieties act as efficient light harvesting antennae, which upon photoexcitation transfer their energy to Eu(III) or Tb(III) for their characteristic D-5(0) -> F-7(J) or D-5(4) -> F-7(J) f-f transitions respectively. The complexes display efficient binding affinity to DNA (K-b = 3.4 x 10(4) - 9.8 x 10(4) M-1) and BSA (KBSA = 3.03 x 10(4) - 6.57 x 10(4) M-1). Europium and terbium complexes give enhanced luminescence upon interacting with CT-DNA suggesting possible luminescence-based sensing applications for these complexes. Complexes 1-3 show moderate cleavage of supercoiled (SC) DNA to its nicked circular (NC) form on exposure to UV-A light of 312 nm involving formation of singlet oxygen (O-1(2)) and hydroxyl radicals (cOH) in type-II and photoredox pathways. Eu(III) and Tb(III) complexes exhibit remarkable photocytotoxicity with human cervical cancer cell line (HeLa) (IC50 = 20.7-28.5 mM) while remaining essentially noncytotoxic up to 150 mM in the dark. Complexes are nontoxic in nature thus suitable for designing cellular imaging agents. Fluorescence microscopy data reveal primarily cytosolic localization of the Eu(III) and Tb(III) complexes in HeLa cells.

Efficient topological localization using orientation adjacency coherence histograms

This paper describes an efficient vision-based global topological localization approach that uses a coarse-to-fine strategy. Orientation Adjacency Coherence Histogram (OACH), a novel image feature, is proposed to improve the coarse localization. The coarse localization results are taken as inputs for the fine localization which is carried out by matching Harris-Laplace interest points characterized by the SIFT descriptor. Computation of OACHs and interest points is efficient due to the fact that these features are computed in an integrated process. We have implemented and tested the localization system in real environments. The experimental results demonstrate that our approach is efficient and reliable in both indoor and outdoor environments. © 2006 IEEE.

Prueba avanzada de rendimiento de nueve lineas y una variedad comercial de arroz (Oryza sativa L.), bajo condiciones de riego en San Isidro, Matagalpa. Epoca lluviosa, 2005

En la época de postrera 2005, se realizó la evaluación de 9 genotipos de arroz procedentes de Colombia y una variedad comercial de Nicaragua (INTA DORADO). El experimento se realizó en la localidad de Paso Real, de San Isidro, Matagalpa, ubicado a los 12º54 ́ latitud norte y 86º11 ́ longitud oeste, a una altura de 457 msnm. La finalidad del ensayo fue identificar líneas con buen rendim iento de grano, calidad molinera, tolerancia a enfermedades y buena adaptabilidad a las condiciones de riego. El diseño experimental fue el de bloque completo al azar (BCA) con 10 tratamientos y 4 repeti ciones. Utilizándose ANDEVA y separación de media SNK ( ∞ =0.05). En la mayoría de las variables evaluadas se determino que existe efecto significativo y altamente significativo entre los diferent es tratamientos. Los principales resultados evidencian que los genotipos L-9, L-39, POB L1-34, POBL 3- 13, alcanzaron los mayores rendimie ntos con producciones de 5,312, 5,193, 5,082.50, 5,044 kg ha -1 respectivamente superando al testigo INTA DORADO que obtuvo el menor rendimiento con 3,506 kg ha -1 . Los componentes del rendimiento: núme ro de granos por panículas, porcentaje de fertilidad de las panículas, peso de 1000 granos y macollamiento por planta definieron la mayor productividad de los genotipos de mayor rendimiento (L-9, L-39, POBL1-34, POBL 3-13), siendo estos los genotipos que presentaron mayor resistencia a enfermedades. Además estos genotipo s presentan; buen porte de planta (tipo semienano), tolerancia al acame y ciclo intermedio. El testigo INTA DORADO y las líneas L-9, POBL 1-34 presentaron una calidad industrial de 94/06, 92/08 y 92/08, con respecto a la relación de grano entero/quebrado.

Estado forestal del Pinus caribaea Morelet var. Hondurensis en el Pinal, Laguna de Perlas, RAAS

Tbe present study was carried out in the strip of land coast between Pearls Lagoon community and the Caribbean sea, in the nearness of Pinar lagoon, 25 km to the north of Bluefields. The geographical coordinates of the area are 12" 13' N and 83" 42' west. Tbe climate presents an annua! rninfall of 4 250 mm, an avera· ge temperature of 26 "C and a relative humidity of 89 %. The topography is plain and tbe elevation oscillates between O· 10 masl. The ma.in objective of the study was to evaluate the forest conditions in which forest of P. Caribaea var .. Jwndurei'ISis ealled the Pinal are found. The methodology employed consisted of gathering all information using air pllotographs and topograpbieal maps to defined the area and stands group (designed A, B, C, D, E, F and G). Two block and seven stands were found, in which invent.ory lines with sample plots of 500 m1 each one were employed to measure the indivíduals with DBH over 10 cm. The intensily it shows ís of !5% and was measured diameter, height, age and other. In tbis forest there where found seven stands with a total area covered with pine of 312.42 has. The average age is 23 years and estirnated total volume of 97.4 ms of wood. The density is of 60,61 trees hectare, with an average volume of 13.02 m3 /has and a commercial volume of 8.29 m' 1 has. Where found lndices of place 12 (stands G), 9 y 6. Besides, the 6.3.64 % of the trees has a satisfactory tendency of growlh (quality l and 2). lt can be concluded that the resource is in badly state due to intensive exploitations and annual f!fCS; is a young forest (23 years old), dotninated by índi viduals of small diameters (10-25 cm) and medium height (5-25 m); the available areas or with possibilities of being planting are: estimated in 468.64 has. This forest has a half annual increment of 1.4.3 cm/year, which is considered excellent and is c1assified with Clas P-III, FAO Classification by forests stratification.

Empoderamiento de mujeres en programas y proyectos de seguridad alimentaria en siete comunidades del municipio de San José de Cusmapa, Madriz, 2006-2008

El estudio se realizó en siete comunidades del municipio de San José de Cusmapa, ubicado en el Departamento de Madríz. Este municipio se ubica a 34 km al suroeste de la cabecera departamental Somoto, y a 274 km al norte de Managua. El objetivo del estudio fue analizar los factores sociales que influyen en el nivel de empoderamiento de las mujeres en los programas y proyectos de Desarrollo Rural en la Seguridad Alimentaria, implementados en siete comunidades del municipio de San José de Cusmapa. La metodología se realizó en tres fases. La primera fase consistió en la selección de la unidad de análisis y población en estudio, conformada por las comunidades San Francisco de Imire, Ángel 1, Ángel 2, El Mamey, Los Llanitos, El Mojón y El Apante. Estas comunidades fueron las que trabajaron con programas y proyectos de seguridad alimentaria y nutricional en el Municipio. Para la selección de la muestra se utilizó el muestreo de sujetos tipos. La revisión bibliográfica consistió en la recopilación de información y depuración de la misma en base a los intereses de la investigación. La segunda fase consistió en la recolección, procesamiento y análisis de la información. El levantamiento de los datos primarios se realizó por medio de talleres comunitarios, entrevistas, observación, árbol de problemas, informantes claves y caracterización municipal. Para el procesamiento de los datos primarios se diseñaron tablas de salida para agrupar la información ordenándolos según las variables planteadas. El análisis de la información permitió ubicar las comunidades en escenarios de niveles de empoderamiento. La tercera fase consistió en la elaboración del informe final, del cual se redacto un primer borrador, un segundo borrador que permitió validar y hacer las correspondientes correcciones para la elaboración del informe final. El análisis de los factores sociales que influyen en el nivel de empoderamiento de las mujeres y las características socioculturales de las comunidades permitió la ubicación de cada una de las comunidades en escenarios: I escenario óptimo para el empoderamiento, II escenario con oportunidad para el empoderamiento, III escenario con limitaciones para el empoderamiento y IV escenario con extremas limitaciones para el empoderamiento. La organización, capacitación, comunicación y participación en las comunidades son factores que limitan la toma de decisiones en los asuntos que ponen en riesgo el desarrollo de las familias. Se recomienda la interacción entre instituciones para fortalecer acciones en pro del desarrollo de las comunidades, el trabajo de desarrollo organizativo a nivel de agencia y comunidad, y la creación de redes que le permita a los comunitarios ser autogestionarios. La capacitación debe realizarse en función de la efectiva participación de los comunitarios, de manera que permita en mediano y largo plazo la implementación de técnicas en seguridad alimentaria.

First-passage failure of quasi-integrable Hamiltonian systems

The first-passage failure of quasi-integrable Hamiltonian si-stems (multidegree-of-freedom integrable Hamiltonian systems subject to light dampings and weakly random excitations) is investigated. The motion equations of such a system are first reduced to a set of averaged Ito stochastic differential equations by using the stochastic averaging method for quasi-integrable Hamiltonian systems. Then, a backward Kolmogorov equation governing the conditional reliability function and a set of generalized Pontryagin equations governing the conditional moments of first-passage time are established. Finally, the conditional reliability function, and the conditional probability density and moments of first-passage time are obtained by solving these equations with suitable initial and boundary conditions. Two examples are given to illustrate the proposed procedure and the results from digital simulation are obtained to verify the effectiveness of the procedure.

高超声速小钝锥尾流化学非平衡辐射研究

本文主要目的是研究化学非平衡对高超声速小钝锥尾流辐射的影响。计算结果表明：激发发射辐射比化学发光辐射重要，红外辐射比可见光辐射重要。结果还表明：由化学非平衡瞬时辐射模型计算求得的ＮＯ５．３μ的辐射能比由局部平衡辐射模型求得的辐射能大３０～７０％。由此可知，小钝锥尾流的化学非平衡辐射模型对辐射的影响是不能忽略的。

高寒草甸地区牧草生长量模拟模式研究

本文讨论了土壤含水量和蒸散量对牧草生长量的影响过程，提出牧草干物质增长模式，并根据青海海北高寒草甸地区的气象条件，对牧草生长量模式进行数值模拟，同时，与实测值进行比较，模拟结果与实测值趋向一致，可为牧草产草量预报提供一定实用价值和科学依据。

集中弯矩作用下圆弧裂纹的弯曲问题

Ｓｃｈｗａｒｚ对称原理结合复应力函数的奇异性分析的方法，对于分析集中载荷问题有独特的优越性．本文利用这个方法研究了任意位置的集中弯矩作用下含共圆圆弧裂纹板的弯曲问题，获得了一般问题解答．给出一个实际重要情形的封闭形式解；最后求得了弯曲应力强度因子公式．本文公式的特殊情形，与现有经典结果吻合．