خيارات البحث
النتائج 1 - 10 من 27
Effect of hot water upon Centrosema pubescens and Stylosanthes guianensis seedlings | Efecto del agua caliente en la germinacion de diez especies arboreas
1999
Toral, O. | Gonzalez, Y. (Instituto Superior Agroindustrial "Camilo Cienfuegos", Matanzas (Cuba). Estacion Experimental de Pastos y Forrajes "Indio Hatuey")
Influence of roasting on the water sorption isotherms of nuts / Influencia del tueste sobre las isotermas de sorción de agua de diferentes frutos secos النص الكامل
1996
Martínez-Navarrete, N. | Chiralt, A.
This work studies the influence of the roasting process on sorption isotherms of almond, hazelnut and peanut over the normal range of storage temperatures (5, 25 and 45 °C) The results obtained showed that water sorption properties of unroasted nuts are affected by fat content. The mono layer moisture content and water affinity (sorption heat, Qₛ) increased when the nut fat content decreased. After roasting, a more homogeneous water affinity was observed for the different products, although fat content still affected the monolayer capacity. Also, roasting reduced mono layer moisture content and Qₛ values in each sample and made the moisturizing process less spontaneous (decreasing the thermodynamic driving force). These results are consistent with an increase of the hydrophobicity of the cellular components of nuts due to the enhancement of lipid interactions. The water binding properties of active points in the roasted products were reduced and, hence, some water sorption active points disappeared.
اظهر المزيد [+] اقل [-][Stimulation for budding in apple tree 'Agua Nueva II']
1994
Miranda Blanco, Jose Luis
Se determino bajo condiciones controladas, los requerimientos de frio y calor del cultivar de manzano agua nueva II, se evaluo en campo la acumulacion de frio, la necesidad de calor y la forma que afecta la aplicacion de estimuladores de brotacion, asi como la concentracion de carbohidratos durante el letargo. Se establecieron dos experimentos, bajo disenos bloques completamente al azar con arreglo de tratamiento factorial. Uno bajo condiciones controladas con 10 tratamientos en base a Unidades Frio (0, 200, 300, 400, 450, 500, 550, 600, 800 y 1000), proporcionadas a varetas colectadas cuando los arboles se defoliaron, a 6+-0.5 grados C y posteriormente en camara de ambiente controlado se proporciono calor (25 grados C, 11 horas de luz y 60-80 % de humedad relativa); el otro bajo condiciones de campo, donde se evaluaron los estimuladores dormex 10 ml L-1 y 20 ml L-1, solos y combinados con citrolina 10 ml L-1, mas el testigo sin aplicacion. El mejor tratamiento bajo condiciones controladas por porcentaje mas alto de brotacion estimada, fue el que recibio 550 Unidades de Frio (UF), con un requerimiento de calor de 24,108 Grados Hora Desarrollo, sin embargo los que recibieron 450, 500 y 600 estadisticamente fueron iguales. Se encontro una correlacion positiva significativa en el requerimiento de GHD grados C para brotacion vegetativa en condiciones controladas y de campo. Bajo condiciones de campo, el mejor fue dormex 20ml L-1 + citrolina 10ml L-1, que uniformizo e incremento el porcentaje de yemas vegetativas abiertas; para numero de racimos florales, amarre de fruto, rendimiento y variables de calidad, no hubieron diferencias significativas entre tratamientos. En cuanto a la concentracion de carbohidratos en periodo de letargo, la tendencia de los azucares solubles fue incrementar hacia la salida de letargo, lo contrario ocurrio en almidon, cuya concentracion disminuyo con la acumulacion de frio durante letargo y hacia inicio de brotacion en primavera.
اظهر المزيد [+] اقل [-]Changes in the chemical parameters during the production of água-mel from Portugal | Cambios en los parámetros químicos durante la producción de água-mel de Portugal النص الكامل
2018
Miguel, Maria Graça | Aazza, Smail | Antunes, Maria Dulce | Faleiro, Maria Leonor
Água-mel is a honey-based traditional product typically produced in southern Portugal. The evolution of some parameters during its production using two distinct containers (aluminium and stainless steel with a water cooling system) and two heating sources (gas heating and electricity) were evaluated. All parameters, except moisture, increased over time, reaching a ‘plateau’ after 8 h of heating. Moisture, free acidity, HMF (hydroxymethylfurfural), colour, melanoidins, phenols and glucose depended on the producer and procedure for obtaining água-mel. Kinetic parameters and correlation coefficients were determined. In general, changes in parameters during água-mel production followed zero- and/or first-order kinetics, depending on the producer and heating system.
اظهر المزيد [+] اقل [-]Biomasa, rendimiento, eficiencia en el uso del agua y de la radiacion solar del agrosistema girasol-frijol | Biomass, yield, and water and radiation use efficiency in the agrosystem of sunflower and common bean
2006
Morales-Rosales, E.J. | Escalante-Estrada, J.A. | Tijerina-Chavez, L. | Volke-Haller, V. | Sosa-Montes, E.
The study was conducted during the summer of 2002. The treatments were monocropping and intercropping the common bean Canario 107, Bayomex (determinate type), Michoacan (indeterminate type), and sunflower cv. Victoria. Sowing took place on May 25, 2002 at a population density of 4.2 (bean) and 8.3 (sunflower) plants m(-2), respectively, in a clay texture soil, with a pH of 7.8 and was fertilized with 100-100-00 of NPK. The experimental design was randomized blocks with four replications. In neither of the crops the phenology, heat units nor evapotranspiration were affected by the sowing system. The heat units (HU) and evapotranspiration (ETc) of de sown crops at physiological maturity were 1521 HU and 279.6 mm for cv. Victoria, 658 HU and 201.3 mm for Canario 107, 811 HU and 213.7 for Bayomex, and 1041 HU and 241.7 mm for Michoacan. The combined agrosystem of sunflower and bean was more efficient in the use of resources in agricultural production. The combination of the Victoria sunflower and the Michoacan bean showed higher efficiency in the use of water and in the use of radiation and, as a result, greater production of biomass and yield. The land equivalent ratio for seed yield obtained with the combination of Victoria plus Canario 107, Victoria plus Michoacan, and Victoria plus Bayomex was 1.6, 1.9, and 3.0, respectively. This shows an advantage for the yield of combined crops over monocrops by 60, 90, and 200%, respectively.
اظهر المزيد [+] اقل [-]Phenology, yield and water use efficiency of sunflower in function of environment and nitrogen / fenologia, rendimiento y eficiencia en el uso del agua en funcion del ambiente y nitrógeno / phénologie, rendement et efficacité de l’utilisation de l’eau en fonction des environs et de l’azote chez le tournesol النص الكامل
2013
Olalde G., Víctor M. | Escalante E., J Alberto | Mastache L., Angel A.
During the rainy season of 1998, a field experiment was established in Cocula, Guerrero (hot subhumid climate, Awo) and in Montecillo, México (semiarid climate, BS₁), to evaluate the effect of nitrogen (0, 10 and 20 g m⁻²) and environment on phenology, yield and its components, water use efficiency (WUE), and crop evapotranspiration (ETc) and heat units (HU) accumulated during the growth cycle of sunflower (Helianthus annuus L.) cv. Victoria. The crop was planted on June 1 at a density of 7.5 pl m⁻² in both climates. In Cocula, maximum and minimum temperatures were more extreme and rainfall was more intense, while soil was poor in total nitrogen, compared with Montecillo. Crop growth, yield and its components, and water use efficiency were affected significantly by the environment, nitrogen and the interaction environment * nitrogen. The crop cycle in the hot environment was 36 days shorter, with a greater accumulation of HU and ETc. Yield and its components and water use efficiency were significantly higher in Cocula. Nitrogen positively affected the evaluated variables. The interactive effect of environment * nitrogen was observed clearly, since in Cocula there was response to the application of nitrogen in most of the variables evaluated, while in Montecillo there was not.
اظهر المزيد [+] اقل [-]Extrapolating the bypass potential of treated Madre de agua (Trichanthera gigantea Nees) leaf meal as protein source in Rumen-Fistulated Brahman Cattle النص الكامل
2019
Atole, Angelo Francis F. | Bestil, Lolito C.
This study assessed the effectiveness of formaldehyde, heat, and tannic acid treatments of madre de agua leaf meal (MALM) in reducing the degradation of dry matter (DMD) and crude protein (CPD) in the rumen for increased supply of bypass protein at the intestinal level. The experiment utilized a rumen-fistulated Brahman bull fed with chopped Napier grass soilage (basal diet) and MALM (test diet) at 70:30 basal:test diet ratio. Nylon bags (porosity of ±53μm) containing the treated MALM were incubated in the rumen for 24, 48 and 72 hours following the “sequential addition” method forin situ degradation measurement. Results showed that DMD of MALM was significantly reduced by formaldehyde treatment after 24-h and 48-h period of incubation than the untreated. This was followed by tannic acid treatment, though the reduction was significant only after 48-h incubation than the untreated. At 72-h period of incubation, DMD remained to be significantly lowest with formaldehyde treatment than the untreated or heat and tannic acid treatments. A similar pattern of differences in DMD rate (%/h) was observed as that of DMD (%). The CPD of MALM was also significantly reduced with formaldehyde treatment after 24-h incubation than the untreated. At 48-h incubation, all treatment methods showed significant protection of protein in MALM over that of the untreated. At 72h, formaldehyde and heat treatments significantly reduced the CPD of MALM compared to the untreated. A similar pattern of differences in CPD rate (%/h) was observed as that of CPD (%). Among treatment methods, the use of formaldehyde is the best, followed by tannic acid treatment, in achieving rumen bypass and promoting greater amino acid supply at the intestinal level.
اظهر المزيد [+] اقل [-]Oxidación en vapor de agua del acero inoxidable AISI 316 recubierto con Al-Si por deposición química de vapor en lecho fluidizado
2014
Arevalo, José Luddey Marulanda | Gallo, Oscar Alucema | Jaimez, Jairo Alberto Barón
Stainless steel AISI 316 was coated with aluminum-silicon by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) to 540°C and subsequently heat treated to improve its mechanical properties and its behavior against oxidation, by inter diffusion of the alloying elements. Later, oxidation was performed austenitic stainless steel aluminum-silicon coated at temperatures of 700 and 750°C, in an environment with 100% steam, to evaluate their performance. Mass gain graphs were made and oxide films were analyzed by SEM and X-ray diffraction to observe the morphology of the oxides. Thermodynamic simulation was carried out during oxidation in water vapor of the substrates for possible solid phases which could be formed. The form of attack at 750°C is similar to 700°C, although the rate of oxidation is increased, because the diffusion of the alloying elements and the oxidation reactions are faster. These coatings have good resistance to oxidation in water vapor and forming an alumina surface layer which protects the substrate from corrosion attack.
اظهر المزيد [+] اقل [-][Soil aggregate stability in pine forests from Galicia [Spain]: effect of fire and its relationship with the organic matter and water repelence] | La estabilidad de los agregados del suelo en pinares de Galicia: efecto del fuego y su relación con la materia orgánica y la repelencia al agua
2010
Varela, M.E., Universidad de Vigo (España). Facultad de Biología | Rodríguez Alleres, M., Universidad de Vigo (España). Facultad de Biología | Benito, E., Universidad de Vigo (España). Facultad de Biología | Keizer, J.J.
The fate of submarine fresh groundwater reservoirs at the New Jersey shelf, USA | Devenir de nappes d’eaux douces sous-marines, au niveau du plateau continental du New Jersey, Etats-Unis d’Amérique El destino de los reservorios submarinos de agua subterránea dulce en la plataforma de Nueva Jersey, EEUU 美国新泽西州陆架海底地下淡水库的传输 O destino dos reservatórios subterrâneos de água doce submarinos na plataforma de Nova Jersey, EUA النص الكامل
2019
Thomas, A. T. | Reiche, S. | Riedel, M. | Clauser, C.
The existence of submarine fresh groundwater has been recorded at continental shelves worldwide. The dynamic preservation and lifetime of fresh groundwater in the offshore environment remains an open hydrogeological problem. The mechanisms and time scales of fresh groundwater preservation are examined using numerical simulations based on a geologically representative model of the New Jersey shelf, USA. Utilizing two-dimensional depth-migrated seismic and well data, a detailed hydrogeological model is built, with a vertical resolution of 10 m. The model captures the highly heterogeneous shelf environment and accounts for porosity compaction trends derived from core data. The results show transient coupled simulations of groundwater flow and heat and salt transport from the late Pleistocene until present day and projected 18,000 years into the future. They reveal freshwater preservation patterns and yield simulated borehole salinity profiles broadly consistent with field observations. The simulations show that freshwater intervals of a thickness of 200–300 m and lateral extent of tens of kilometers may have been preserved from the Last Glacial Maximum until today. It was found that approximately 30–45% of the initial freshwater volume remains preserved after 12,000 years, depending on the recharge boundary condition. The preserved volume ranges between 15 and 30% after 30,000 years. These results improve the understanding of submarine preservation of fresh groundwater through an interdisciplinary approach which integrates seismic imaging, hydrogeological modeling and high-performance numerical simulation.
اظهر المزيد [+] اقل [-]