Optoelectronic properties of discotic materials for device applications

Applied Science

Acoustic analysis of sound transmission in a mixed-use development using Statistical Energy Analysis

Statistical Energy Analysis (SEA) is an energy-based method used to estimate the vibro-acoustic response of complex structures by analysing the energy exchange between subsystems. It is widely applied in a variety of industries due to its relative simplicity, reliability and low computational cost. This paper presents research into the suitability of SEA as a design aid in the construction process of developments containing noise-sensitive spaces. The focus is on the challenging case of sound transmission between non-adjacent spaces. SEA-based models are developed for this study with the aid of a commercial software package. The models provide predictions of the structure-borne flanking sound transmission between cinema auditoria and residential apartments within a mixed-use development. Input data obtained from drawings and final construction details are used to inform the models which are then validated using measured data from a series of airborne sound insulation measurements. An iterative approach is adopted to fine-tune the prediction performance of the models developed. The performance is also evaluated for varying number of building elements and connections. For this case study, it was found that SEA-based technique can serve as a valuable design aid in the early stages of acoustic design process, particularly in the challenging cases of non-adjacent spaces. However, inherent limitations and uncertainties should be considered

Le transit digestif chez le lapin. Repartition de la radioactivite apres ingestion d'aliment marque au cerium-141 (III)

National audienc

Le transit digestif chez le lapin. Utilisation du cerium-141 : etude methodologique et descriptive (I)

National audienc

LACTANCIA DE OVEJAS MANCHEGAS EN PRADOS ARTIFICIALES: CALIDAD DE DIETA, RENDIMIENTOS PRODUCTIVOS Y EFECTO DE LA SUPLEMENTACION

Se ha realizado un ensayo encaminado a conocer la calidad de la dieta in gerida por ovejas Manchegas cuya lactación transcurrió sobre un prado artificial polifito. Se determinó la composición porcentual de especies pratenses, disponibilidad de biomasa durante el periodo de pastoreo y re husos al final del mismo así como el efecto del pisoteo, heladas y marchitamiento. Comparando la composición químico-bromatológica del prado con la de mués tra5de extrusa esofágica resultó que las primeras presentaron contenidos en PB del 15,6% y una DMS del 62.1%, siendo la PB del 18.5% y la DMS del 81.1% en la extrusa esofágica con lo que la selección parece relacionarse con la digestibilidad. Mediante marcadores externos se estimó la ingestión de M.S. (2461 ± 217 g) deduciendo así los nutrientes aportados por la dieta para cubrir las necesidades del animal. Se estudió así mismo el efecto de la administración de tres niveles de concentrado (0, 0.5 ¡ y 1 kg de una mezcla de 75% de cebada y 25% de habines) sobre la producción lechera, pérdida de peso de las madres y ganancia de peso vivo de los corderos observándose una pérdida de peso significativamente mayor en las ovejas no suplementadas y no detectándose grandes diferencias en la producción lechera e incremento de peso de los corderos al aumentar el concentrado de 0.5 a 1 kg.como dato más destacable del trabajo.cabe señalar la gran capacidad selectiva de la oveja Manchega para ingerir una dieta de calidad nutritiva mayor que la media del recurso disponible y la posibilidad de completar un ciclo productivo de gestación-lactación combinando la utilización de rastrojeras de cereales y prado reservado de otoñ

Effects of dietary fiber sources on volatile fatty acid production, intestinal microflora and mineral balance in rabbits

An experiment was conducted to evaluate the effect of alfalfa hay meal (AHM), olive pulp meal (OPM) and grape pulp meal (GPM) on volatile fatty acid (VFA) production, intestinal flora and mineral balance in rabbits. Eighteen New Zealand White rabbits, 45 days of age, were used. The sources of fiber were fed at the 28% level in a practical diet for a 33 day period. The samples of AHM, OPM and GPM contained 409 g kg-1, 556 g kg-1 and 593 g kg-1 neutral detergent fiber (NDF) in the dry matter, respectively. Liveweight was not affected by dietary fiber, but feed intake showed significant differences (P < 0.05). An increase in the pH value of cecal digesta was observed in animals fed the AHM diet compared with those fed GPM (5.72 vs. 6.06). The total VFA concentrations were higher for both OPM and GPM diets than for the AHM diet (153 mM l-1 and 151 mM l-1 vs. 65.6 mM l-1). The proportion of acetate in the total VFA was higher (P < 0.05) and that of the propionate lower (P < 0.05) in the AHM group than in the OPM and GPM groups. Valerate was not detected in the cecal contents of rabbits fed the OPM or GPM diets. High counts of aerobic bacteria and faecal streptococci were presented in the cecum of the OPM group. Dietary fiber source affected the count of staphylococci. Sulfite-reducing clostridia increased in the ileum and cecum content of both OPM and GPM groups. Slight differences were observed in the numbers of coliforms and lactic acid bacteria in the intestinal content of the rabbits. The absorption of Ca, P and K was higher (P < 0.01) in the AHM group. Mg and Zn were less well absorbed (P < 0.01) in the GPM group. Low levels of Fe and Mn absorption (P < 0.05 and P < 0.01, respectively) were obtained in rabbits fed the OPM diet. An increase in Cu absorption (P < 0.01) was found in the OPM group. Fiber sources did not influence Ca and Fe balance. The P balance was higher (P < 0.05) in the AHM than in the GPM group. The AHM diet showed the lowest Mg and K balance (P < 0.01). The Cu and Zn balance was lower in the GPM than in the AHM and OPM groups (Cu, 0.13 mg day-1 vs. 0.45 mg day-1 and 0.33 mg day-1; Zn, -0.97 mg day-1 vs. 0.47 mg day-1 and 0.04 mg day-1, respectively). Except for K, no effect of fiber source could be detected in plasma mineral levels. © 1994

LE TRANSIT DIGESTIF CHEZ LE LAPIN. I. — UTILISATION DU CÉRIUM-I4I : ÉTUDE MÉTHODOLOGIQUE ET DESCRIPTIVE

International audienc

LE TRANSIT DIGESTIF CHEZ LE LAPIN. II. — RÉPARTITION DE LA RADIOACTIVITÉ APRÈS INGESTION D'ALIMENT MARQUÉ AU CÉRIUM-I4I

International audienc