Plan de negocios en las comunidades de la Laguna Negra y San Isidro del municipio de Camoapa

El presente trabajo es una investigación de campo de tipo descriptivo, documental, no experimental y se realizó según las normativas de la Universidad Nacional Agraria. En primer lugar, se realizaron las visitas a las comunidades de San Isidro y La Laguna Negra con el propósito de observar y conocer la situación socioe conómica de las familias y a la vez conseguir el involucramiento y aprobación de la población para la utilización de las casas comunales de una forma viable y su mejoramiento. Se utilizó el método matricial para elegir una idea de negocio a ejecutar y desarrollarla en ambas casas comunales, siendo electa la elaboración de un plan de negocio que incluye la venta de abarrotes, medicinas y herramientas del campo. Los resultados están basados a la estructura de un Plan de Negocios, teniendo unas compras proyectadas para el primer mes de C$ 109,867.09 y unas ventas de C$ 128,461.98 en ambas casas obteniendo una ganancia de C$ 18,594.89; con una ganancia anual de C$ 223,138.68. Para la iniciación del negocio se pretende realizar un crédito de C$ 243,796.49 con una tasa de interés del 14%, con pagos anuales; se obtuvo un valor actual neto de 82,510.62 y una tasa de interés rentable de 19.34%. Como la idea principal era la mejora de las casas comunales se ejecutó la elaboración de un presupuesto de inversión el cual asume una cantidad de C$ 112,929.40 (Ciento doce mil novecientos veinte y nueve córdobas con 40/100); la cual se incluirá en la inversión inicial sustentada en el financiamiento.

爆炸焊接飞板运动的研究

本文通过量纲分析指出,爆炸焊接飞扳运动是几何相似的。不过,由于起爆端端部稀疏波的作用,飞板运动存在着非稳定运动段,在该段内确定飞板极大动态弯折角的相似参数有两个:一个是R;一个是炸药厚度与爆轰波波阵面距起爆端距离之比he/VDt。在稳定运动段内,确定飞板极大动态弯折角的相似参数只有一个R。试验结果证明,最纲分析的结论是正确的;并确定了he/V_(Dt)=0.04是稳定运动和非稳定运动的分界,它是制定大厚度扳焊接方案的依据之一。

不可压缩粘性导电流体一维定常及不定常流动问题

<正> 1.引言 磁流体力学与流体力学的区别之一是有些物理量不能事先给定,这使得在确定边界条件时会遇到困难。例如,在一般情况下,磁场的边界值不能事先给定。因为当导电流体运动时,感应电流也将产生磁场,就使外加磁场发生畸变。忽视这一点,会使求出的解与实际情况不符。

圆柱高雷诺数层流非定常运动初期流动

本文用离散涡位流理论与边界层理论相结合的方法,研究高雷诺数、不可压、层流情况下圆柱非定常运动的初期流动(圆柱由静止突然起动而后保持匀速运动),给出了柱后旋涡发展的详细过程;流场分布、边界层分离点及阻力等随时间的变化规律。本文耦合计算结果包含了流动过程中边界层、外流与近尾迹三者的相互作用。计算所得的旋涡发展与实验显示的图象十分相似,物面压力与速度分布合理,阻力计算与实验结果相符很好。在分离点耦合计算中将stratford方法应用到准定常边界层情况,计算方法简单结果也较满意。对于准定常变化前分离产生的离散涡,其脱落时间和初始位置,本文根据非定常M. R. S. 分离准则确定。文中还讨论了这些离散涡对柱后旋涡发展及流动的影响。

数控脉冲式X光同步机的研制和应用

本文介绍一种控制多台脉冲X光机同步运行的新型同步机。它具有抗干扰能力强,精度高,使用方便等特点。本文还对干扰机制和抗干扰措施以及仪器使用中如何保证可控精度的问题进行了探讨,并给出了应用结果——雷管爆炸、聚能射流等动态过程不同瞬态的X光照片。

共转圈的奇异性对盘状星系密度波的影响

在气体动力学的星系盘模型中,本文讨论了边际稳定性时共转圈奇异性对中性密度波的影响。结果表明,共转圈奇异性对波的色散关系的影响是全局性的。计算了与银河系相类似的星系模型。共转圈附近波的群速度与自由密度波的关系有很大差异,能够严重地改变密度波传播的能流迴路。除非特定星系模型严格不存在共转奇异性,共转点不会是双零转向点。

An analysis of the effects of symmetrical tilt grain boundaries on the plastic deformation

A numerical investigation on the simple polycrystals containing three symmetrical tilt grain boundaries (GBs) is carried out within the framework of crystal plasticity which precisely considers the finite deformation and finite lattice rotation as well as elastic anisotropy. The calculated results show that the slip geometry and the redistribution of stresses arising from the anisotropy and boundary constraint play an important role in the plastic deformation in the simple polycrystals. The stress level along GB is sensitive to the load level and misorientation, and the stresses along QB are distributed nonuniformly. The GB may exhibit a softening or strengthening feature, which depends on the misorientation angle. The localized deformation bands usually develop accompanying the GB plastic deformation, the impingement of the localized band on the GB may result in another localized deformation band. The yield stresses with different misorientation angles are favorably compared with the experimental results.

Molecular dynamics studies on the local disordering of σ3 and σ11 grain boundaries in aluminium bicrystal

Molecular dynamics (MD) simulations using Morse interaction potential are performed in studies of [110] symmetrical tilt grain boundary (GB) structures with mis-orientation angles 50.5 degrees(Sigma 11), 129.5 degrees(Sigma 11), 70.5 degrees(Sigma 3) and 109.5 degrees(Sigma 3) at various tempratures. The GB structures are found to start local disordering at about 0.5T(m)(T-m is the melting point of aluminium) for 50.5 degrees(Sigma 11), 0.32T(m) for 129.5 degrees(Sigma 11) and 0.38T(m) for 70.5 degrees(Sigma 3), respectively. These results agree with conclusions deduced from the anelastic measurements. But, for twin-boundary structure 109.5 degrees(Sigma 3), this disordering has not been found even when temperature increases up to 0.9T(m).

Fatigue crack-growth rate in ferrite martensite dual-phase steel

An empirical study is made on the fatigue crack growth rate in ferrite-martensite dual-phase (FMDP) steel. Particular attention is given to the effect of ferrite content in the range of 24.2% to 41.5% where good fatigue resistance was found at 33.8%. Variations in ferrite content did not affect the crack growth rate when plotted against the effective stress intensity factor range  which was assumed to follow a linear relation with the crack tip stress intensity factor range ΔK. A high  corresponds to uniformly distributed small size ferrite and martensite. No other appreciable correlation could be ralated to the microstructure morphology of the FMDP steel. The closure stress intensity factor , however, is affected by the ferrite content with  reaching a maximum value of 0.7. In general, crack growth followed the interphase between the martensite and ferrite.

Dividing the fatigue crack growth process into Stage I and II where the former would be highly sensitive to changes in ΔK and the latter would increase with ΔK depending on the  ratio. The same data when correlated with the strain energy density factor range ΔS showed negligible dependence on mean stress or R ratio for Stage I crack growth. A parameter α involving the ratio of ultimate stress to yield stress, percent reduction of area and R is introduced for Stage II crack growth so that the  data for different R would collapse onto a single curve with a narrow scatter band when plotted against αΔS.

Explorations of electric-current system in solar active regions .1. Empirical inferences of the current flows

In this paper we explore techniques to identify sources of electric current systems and their channels of flow in solar active regions. Measured photospheric vector magnetic fields (VMF) together with high-resolution white-light and H filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. Simple mathematical constructions of fields and currents are also adopted to understand these data. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980. The main results are: (i) In unipolar sunspots the current density may reach values of 103 CGSE, and the Lorentz force on it can accelerate the Evershed flow, (ii) Spots exhibiting significant spiral pattrn in the penumbral filaments are the sources of vertical major currents at the photospheric surface, (iii) Magnetic neutral lines where the transverse field was strongly sheared were channels along which strong current system flows, (iv) The inferred current systems produced oppositely-flowing currents in the area of the delta configuration that was the site of flaring in AR 2372.