Efficacy of combined acid-heat treatments to protect crude protein (CP) against ruminal degradation has not been extensively researched. Four in vitro trials (Daisy technology) with orthophosphoric and malic acids were performed to examine effects on protection of sunflower meal protein. In Trial 1, effects of the solution volume for adding two doses of orthophosphoric acid (0.4 and 1.2 eq/kg sunflower meal) were tested using five dilution volumes (80, 160, 240, 320 and 400 ml/kg of feed) for each acid dose. Samples were heated at 608C. The quantity of CP that remained undegraded after 20 h in vitro (IVUCP) increased with the amount of acid added ( P 5 0.01). Increasing the dilution volume also tended ( P 5 0.065) to increase IVUCP. Therefore, a dilution volume of 400 ml/kg was employed in all further trials. In Trial 2, treatments with solutions of orthophosphoric and malic acids (1.2, 2.4, 3.6 and 4.8 eq/kg) and 608C of drying temperature were used. Increased CP protection with increased acid doses was described. In this and further trials, higher protective effects of malic acid than orthophosphoric acid were also shown. In Trial 3, the effects of both these acids, four acid concentrations (0.6, 1.2, 1.8 and 2.4 eq/kg) and three levels of heat treatment required for drying the samples (100, 150 and 2008C for 60, 30 and 20 min, respectively) were evaluated. An interaction acid type 3 concentration 3 temperature was shown. In addition, interactions concentration 3 temperature was shown in each acid. With heat treatments of 1008C to 1508C, benefits were not obtained after increasing the acid dose over 0.8 eq/kg. The increase of the heat treatments to 2008C and the acid dose up to 1.2 eq/kg increased protection, but to exceed this dose did not improve protection. In Trial 4, available lysine, CP solubility in McDougall buffer and IVUCP were compared after treatment with water or solutions (0.8 eq/kg) of orthophosphoric or malic acids using 1008C and 1508C heat treatments as described in Trial 3. No effects on available lysine were observed. Both CP solubility and IVUCP were reduced to a greater degree by acids than by water treatment. The results showed a high effectiveness of acid-heat treatments. Levels of protection are dependent on the acid dose, its dilution, acid type and drying conditions.
Nowadays, nobody can deny that climate change is a reality and that the life cycle of buildings contributes greatly to that reality. Therefore, proposals such as the circular economy must be integrated into the construction sector. This article shows part of the results of a research project whose objective is to introduce circular economy criteria in building materials, seeking new uses for construction and demolition waste from buildings. In particular, this article analyses the possibility of replacing fibres currently used to reinforce cement mortars with recycled fibres. After consulting the bibliography, we can conclude that some studies analyse the behaviour of cement mortars reinforced with different types of fibres, but none has been found that analyses the behaviour of these mortars for the application of continuous coatings. For this purpose, a two-stage experimental plan is designed to test cement mortar samples with different types of fibres, recycled fibres and commercial fibres, taking into consideration the characteristics that these mortars have to comply to be applied as continuous coatings. Moreover, a detailed study about the porosity of these mortars and its influence on how the mortars behave with regard to compression, water vapour permeability and impermeability has been conducted. From the results obtained, it can be concluded that the mortars containing recycled fibres have very similar resistance, absorption and permeability values to those containing commercial fibres, so that they might be suitable for application as external coatings.
Cabral y Alberto Marinoni en las primeras páginas del nº1 de rita_ fue una grata sorpresa. La obra de Benítez es un estimulante nuevo capítulo en la larga tradición latinoamericana de arquitectura de fábrica de ladrillo; o más bien de otra tradición dentro de la tradición, también en mucha medida latinoamericana: la de repensar la arquitectura de fábrica de ladrillo. E incluso, haciendo una pirueta, de una tercera derivada de esa tradición: la de repensar la arquitectura de ladrillo desde las posibilidades que ofrece la prefabricación. El embrollo anterior merece un párrafo aclaratorio. En América Latina, como en tantos lugares del mundo, han existido desde siempre tradiciones de construcción con fábrica de base arcillosa. En muchas zonas las raíces ancestrales se mezclaron con las tradiciones españolas y portuguesas, a su vez mezcla de las árabes y romanas. Esta mezcla de mezclas posibilitó combinaciones riquísimas, de las que están llenas las villas y ciudades de todo el continente. A mediados del siglo XX, en un contexto de escasez de recursos, toda esta amalgama de tradiciones se combinó con las grandes dosis de inquietud ingenieril y talento arquitectónico características del momento, propiciando una extraordinaria revitalización de la arquitectura de fábrica. Una arquitectura de fábrica repensada, voluntariamente nueva, con otros referentes, en la modernidad o en la posmodernidad arquitectónica, diferente en lo formal y en lo conceptual, pródiga en muros reclinados, arcos cruzados, láminas de doble curvatura o bóvedas que no siempre acaban de serlo. Los grandes edificios de cerámica armada de Eladio Dieste 1 son los ejemplos mas conocidos de esta revitalización, pero otras muchas reflexiones, con resultados menores en escala pero no en interés, surgieron entonces y, como demuestra la casa Abú & Font 2 , han seguido haciéndolo hasta ahora. Una de esas arquitecturas repensadas es la que se basa en elementos constructivos que, en lo sucesivo, llamaremos "bóvedas prefabricadas de ladrillo". Como se verá, se trata de un sistema en el que concurren dos ideas principales: de un lado, una de las grandes pasiones de las décadas de los años 60 y 70 del pasado siglo XX, la de la construcción prefabricada, idónea para garantizar procesos de producción ágiles y mecanizados; de otro, la de la construcción abovedada ligera con obra de fábrica que, pese a ser, en lo esencial, un sistema de construcción tradicional, contaba con algunas ventajas que podían reivindicarse, desde la óptica de aquellos años, con causa: su bajo coste, su facilidad de producción y su moderado consumo energético. Conviene, antes de entrar en detalle, contextualizar los comentarios anteriores. Las décadas mencionadas, las de los años 60 y 70 del pasado siglo XX, fueron pródigas en utopías arqui-Resumen pág 56 | Bibliografía pág 60 [1] Ilustración del proceso de construcción de una bóveda tabicada (Moya, 1993: 20). [2] Construcción de una bóveda tabicada en TRUÑO, A.
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