Comportamiento productivo de cerdos alimentados con desperdicios de cocina y residuos de galleta en la dieta, bajo distintos porcentajes de inclusión

El presente estudio se realizó en la granja porcina de la Universidad Nacional Agraria (U.N.A), ubicada en el Km. 13 a los 86°. 09' 36" longitud oeste y los 12° 08'15" latitud norte de la comunidad de Sabana Grande, Municipio de Managua con un elevación de 56 m sobre el nivel del mar (INETER, 1987). La fase de campo fue realizada de Julio a Octubre de 1999, con el objetivo de evaluar el comportamiento productivo de cerdos en crecimiento, desarrollo y engorde alimentados con tres raciones diferentes: (T1) Desperdicio de Galleta 100%, (T2) Desperdicio de Galleta 75% + Desperdicio de cocina 25%, (T3) Desperdicio de cocina 100%. Se utilizaron 18 cerdos comerciales de ambos sexos, con peso promedio de inicio de 54.86 kg, que fueron distribuidos en tres tratamientos con seis repeticiones con los datos levantados de pesaje de los diferentes tratamientos, se efectúo el análisis estadístico correspondiente al diseño experimental completamente al Azar (DCA) y su correspondiente análisis para las variables en estudio, G.M D. y C.A. Los cerdos que presentaron una ganancia de peso más alta, fueron los que se alimentaron con la ración l00 % de desperdicio de cocina teniendo una ganancia media diaria de 0.758 kg. los cerdos alimentados 75 % DDG, + 25 % DDC, alcanzaron una ganancia de peso promedio de 0.578 kg. mientras que el tratamiento 100% DDG alcanzo una ganancia media de peso promedio de 0.17 kg. El análisis de la ganancia media diaria se demostró con una alfa de 5 %. El análisis estadístico mostró que las diferencias en conversión alimenticia fueron significativas entre tratamientos con un Alfa al 5 %. Al comparar las utilidades generadas entre el T t y T2, estos resultaron financieramente aceptables, de forma similar se comportaron el T1 y T3., no obstante, desde el punto de vista nutricional, estos no cumplieron los requerimientos de la categoría, por lo que el T2, se presentó finalmente como el más aceptable nutricionalmente.

Creep response of sandwich beams with a metallic foam core

The creep response of metallic foam sandwich beams in 3-point bend is investigated numerically for the case of a metallic foam core and two steel faces. The face sheets are treated as elastic, while the foam core is modeled by a viscoplastic extension of the Deshpande-Fleck yield surface. This power-law creeping constitutive law has been implemented within the commercial finite element code ABAQUS. It is found that the beams creep by a variety of competing mechanisms, depending upon the choice of material properties and the geometric parameters. A failure map is constructed and effect of rate dependence on the load-deflection curves is quantified, and compared against the available experimental data.

Convective heat dissipation with lattice-frame materials

This paper presents experimental results on heat transfer and pressure drop for a compact heat sink made of fully triangulated, lightweight (porosity∼0.938), aluminum lattice-frame materials (LFMs). Due to the inherent structural anisotropy of the LFMs, two mutually perpendicular orientations were selected for the measurements. Constant heat flux was applied to the heat sink under steady state conditions, and dissipated by forced air convection. The experimental data were compared with those predicted from an analytical model based on fin analogy. The experimental results revealed that pressure drop is strongly dependent upon the orientation of the structure, due mainly to the flow blockage effect. For heat transfer measurements, typical local temperature distributions on the substrate under constant heat flux conditions were captured with infrared camera. The thermal behavior of LFMs was found to follow closely that of cylinder banks, with early transition Reynolds number (based on strut diameter) equal to about 300. The Nusselt number prediction from the fin-analogy correlates well with experimental measurements, except at low Reynolds numbers where a slightly underestimation is observed. Comparisons with empty channels and commonly used heat exchanger media show that the present LFM heat sink can remove heat approximately seven times more efficient than an empty channel and as efficient as a bank of cylinders at the same porosity level. The aluminum LFMs are extremely stiff and strong, making them ideal candidates for multifunctional structures requiring both heat dissipation and mechanical load carrying capabilities. © 2003 Elsevier Ltd. All rights reserved.

Determinación de período crítico de Plutella xylostella (L) en el cultivo de repollo (Brassica oleracea L.) durante la época de apante

Con el objetivo de determinar el periodo crítico del daño de plutella xylo0stella l. en el cultivo de repollo se estableció un experimento de campo en la época seca (enero-abril, 1989) en el valle de sebaco, Matagalpa. Los tratamiento evaluados fueron diferente periodo de protección, de 0-30,0-50,0-90,30-90,50-90 días después del transplante (DDT) y sin protección utilizando aspersiones de la mezcla de insecticidas DIPEL (bacillus thurigiensis 780 g/ha) y tamaron (metamidofos 1.5 1t/ha). Los resultados indican que las poblaciones de plutella encontradas en las etapas del crecimiento vegetativo y de formación de copa (30-50 DDT) no influyen sobre el rendimiento y la calidad de repollo. Las poblaciones de plutella encontradas en la etapa de formación de la cabeza (50-90 DDT) afectan adversamente el precio de cabeza y el ingreso econom8ico causando pérdidas. Por lo tanto la época de formación de cabeza se puede considerar como el periodo crítico del daño de plutella en repollo. Durante la época de formación de cabeza el nivel de daño económico estimado a través de la relación entre la perdida y las poblaciones de plutella, resulto igual a 0.83 larvas por planta lo que se considera alto en comparación con las cifras reportadas en la literatura.

塑料及纤维增强塑料形变过程的热象研究

<正> 塑料和纤维增强塑料极低的热传导系数使它具备了应用热象技术研究形变过程的特殊的有利条件。本文简要叙述了用红外热象技术研究聚丙烯、聚碳酸脂及短纤维增强聚丙烯拉伸形变过程的研究结果。用上述材料注射成标准拉伸样条,夹装在Instron 1195万能材料试验机上,以指定速度进行拉伸直至断裂。同时用AGA-780红外热象仪记录试件拉伸过程的热图。为考察拉伸速度对形变热的影响,拉伸速度在2～50 mm/m范围内。通过对不同拉伸速度、不同时刻的试件样条热图的分析,得到了试件在拉伸过程中的温升及形变信息,给出了试件样条断裂瞬间的热图和拉伸过程中各时刻的试件温度分布图。实验结果表明,对于所研究的两种塑料,形变热软化效应在屈服和颈缩形成阶段不起主要作

分解刚度法在各向异性多层扁壳理论中的应用

本文按文献[3]中胡海昌阐述的方法,在文献[1]的基础上,将分解刚度法推广应用到各向异性多层扁壳的横向变形、稳定和横向振动问题上去,取得了简单实用、计算工作量和误差都较小的近似计算方法.

A documentação de Paul Otlet : uma proposta para a organização racional da produção intelectual do homem

A pesquisa procura identificar e analisar as circunstâncias e motivações teóricas que levaram ao surgimento, no final do século XIX, da área de estudo denominada Documentação. Apresenta informações biográficas sobre os principais artífices deste projeto, os advogados e bibliógrafos belgas, Paul Otlet e Henri La Fontaine, que visaram ampliar a compreensão sobre o meio social e cultural em que atuaram. Procura ampliar a discussão sobre os fatores que motivaram em 1895 a proposta de organização racional de toda a produção intelectual do homem. Apresenta em linhas gerais a visão abrangente e integradora da Documentação que eliminando barreiras físicas, acessava acervos arquivísticos, bibliográficos e museológicos para o registro integral dos assuntos pesquisados. Discute a utilização da Classificação Decimal de Dewey (CDD) na criação do Repertório Bibliográfico Universal e analisa o processo que levou ao surgimento da Classificação Decimal Universal (CDU). Conclui sugerindo a inclusão desta visão extensiva e integradora da documentação ao referencial teórico da Ciência da Informação. Sugere que o resgate deste aporte teórico poderá contribuir para um melhor enfrentamento dos problemas da gestão do conhecimento registrado, produzido e acumulado até os dias atuais, nos mais diversos formatos, suportes e repositórios.

An Experimental Study on Flame Propagation in Cornstarch Dust Clouds

Following the quantitative determination of dust cloud parameters, this study investigates the flame propagation through cornstarch dust clouds in a vertical duct of 780 mm height and 160 x 160 mm square cross section, and gives particular attention to the effect of small scale turbulence and small turbulence intensity on flame characteristics. Dust suspensions in air were produced using an improved apparatus ensuring more uniform distribution and repeatable dust concentrations in the testing duct. The dispersion-induced turbulence was measured by means of a particle image velocimetry (PIV) system, and dust concentrations were estimated by direct weighing method. This quantitative assessment made it possible to correlate observed flame behaviors with the parameters of the dust cloud. Upward propagating dust flames, from both closed/open bottom end to open/closed top end of the duct, were visualized by direct light and shadow photography. From the observation of propagation regimes and the measurements of flame velocity, a critical value of the turbulence intensity can be specified below which laminar flame propagation would be established. This transition condition was determined to be 10 cm/s. Laminar flames propagated with oscillations from the closed bottom end to the open top end of the testing duct, while the turbulent flames accelerated continuously. Both laminar and turbulent flames propagated with steady velocity from the open bottom end to the closed top end of the duct. The measured propagation velocity of laminar flames appeared to be in the range of 0.45-0.56 m/s, and it was consistent with the measurements reported in the literature. In the present experimental study, the influence of dust concentration on flame propagation was also examined, and the flame propagation velocity was found weakly sensitive to the variations in dust concentration. Some information on the flame structure was revealed from the shadow records, showing the typical heterogeneous feature of the dust combustion process.

合金材料超高周疲劳行为的基本特征和影响因素

合金材料在超高周疲劳下具有与低周和高周疲劳不同的裂纹萌生和扩展行为以及不同的S-N曲线特征.材料的强度、循环加载的频率、所处的环境等都显著影响超高周疲劳的特性.本文综述了合金材料超高周疲劳行为的基本特征和影响因素的研究进展.

Deba barreneko euskarazko komunikazio sistema : tokian tokiko aldizkariaren kazetaritza-genero eta gaien analisia 2000-2004 bitartean

780 p.

Un ejemplo de romanización a través de la epigrafía latina altoimperial: los cultos «indígenas» en el Norte hispano

Anejos de Veleja. Acta; 12 ; Revisiones de Historia Antigua; 7

Derecho latino, organización cívica y élites hispanas

Juan Santos Yanguas y Gonzalo Cruz Andreotti (eds.) ; M. Fernández Corral y L. Sánchez Voigt (cols.)

Seasonal variation of some trace metal concentrations in some fish species on stretch of River Kubanni, Zaria

In a semi-urbanized stretch of river Kubanni, Zaria, seasonal variations of some tree metals (copper, zinc and lead) in fish species (Clarias sp., Tilapia sp and Alestes sp) were investigated over a period of eight months. Water and fish were sampled monthly, pooled separately and seasonal analysis of each trace determined using atomic absorption method. The concentration of each of the elements in water higher in the dry season than during the rainy season. The dry and rainy season concentrations of copper, zinc and lead were 6.85~c10.66 mu gg super(-1)&1.45~c1.10 mu gg super(-1); 2.13~c1.68 mu gg super(-1)&0.1 5~c0.05 mu gg super(-1); and 0.52~c0.50 mu gg super(-1) & 0.31~c0.14 mu gg super(-1) respectively. Similarly, all the three accumulated more zinc and lead in the dry season than during the rainy season. Tilapia species and to some extent, Alestes species being pelagic had a higher concentration of trace metals than Clarias species which is a bottom dwelling fish Tilapia species may therefore be a better indicator species than Clarias species for monitoring trace metals in water bodies. Reasons for the observed variations in the trace metals were discussed