1,585 research outputs found
Membrane processing of grape must for control of the alcohol content in fermented beverages
The great demand of beverages, both alcohol-free and with low alcohol content, is a great challenge for the production of beverages with controlled alcohol content through the use
of sustainable enological practices. The present work addresses this challenge with the processing of grape must by reverse osmosis (RO) for must reconstitution with different sugar
contents prior to the alcoholic fermentation. The original must came from grapes grown in Quinta do Quinto, in Santarém, collected after destemming and mechanic crushing, and
preserved in a refrigerated chamber at -1.6 °C until processing by RO. The RO processing was carried out in Escola Superior Agrária de Santarém, with a pilot plant equipped with RO
spiral wound modules, M38RO, from Alfa Laval, Denmark. The total membrane permeation area is 15 m2. The work pressure was 55 bar. The original must had 23.7 oBrix, a density
of 1108 g.L-1, 15.2% (v/v) of probable alcohol, and a conductivity of 2.01 mS.cm-1. The must reconstitution was carried out, by mixing the concentrated grape must with the vegetal
water produced by RO (permeate) to obtain beverages with a nominal alcohol content of 5%, 7%, 10% and 13% (v/v). The fermentation average temperature was between 18.2 and
19.7 °C, and the final density rounded about 993 g.cm-3. The beverages were analysed by different parameters, including total polyphenols, total anthocyanins, colour intensity and
hue, the coordinates CIELab, alcohol content, total acidity, volatile acidity, pH, free SO2 and total SO2. The attributes of the beverage, corresponding to the visual appearance, aroma
and taste senses, as well as the overall judgment were evaluated by the tasters. The proposed method can produce beverages with controlled low alcohol content. The decrease of the
alcohol content led to lower content of polyphenols compounds which influenced the sensory evaluation.info:eu-repo/semantics/publishedVersio
A non inflationary model with scale invariant cosmological perturbations
We show that a contracting universe which bounces due to quantum cosmological
effects and connects to the hot big-bang expansion phase, can produce an almost
scale invariant spectrum of perturbations provided the perturbations are
produced during an almost matter dominated era in the contraction phase. This
is achieved using Bohmian solutions of the canonical Wheeler-de Witt equation,
thus treating both the background and the perturbations in a fully quantum
manner. We find a very slightly blue spectrum (). Taking
into account the spectral index constraint as well as the CMB normalization
measure yields an equation of state that should be less than , implying , and
that the characteristic size of the Universe at the bounce is , a region where one expects that the Wheeler-DeWitt
equation should be valid without being spoiled by string or loop quantum
gravity effects.Comment: 9 pages, 4 figure
A novel profiling concept leading to a significant increase in the mechanical performance of metal to composite joints
In this work, we designed metal-CFRP joints with a profiled adherend termination to improve the mechanical performance. We have applied several profiles to the edge of titanium adherends which were adhesively bonded to CFRP substrates. We conducted finite element modelling and experimental 4PB (4-Point-Bend) testing to investigate how the geometry of the adherend edge profile effects the mechanical performance of the joint. This work shows that profiling of the metal adherend can result in increases of at least 27% in the peak load, and of at least 272% in the energy dissipated up to critical failure normalised by the mechanical energy
Assessment of different coastal defence structures to promote wave energy dissipation and sediments retention
Coastal areas are an apprized environment by society that will continue
to expand rapidly. Traditional coastal protection structures are commonly deployed to protect coastal areas endangered by natural extreme weather events.
However, due to their limited efficiency and very high costs, more efficient and
sustainable strategies to deal with coastal erosion are imperative.
This research work focuses on the assessment of engineering solutions to mitigate and delay coastal erosion. Three different structure geometries (triangular
prism shape, single detached breakwater and group of two detached breakwaters)
are analysed on a realistic bathymetry, using a combination of numerical models
(SWAN and XBeach) to study the influence of those structures on the coastal
hydro- and morphodynamics. SWAN was used for hydrodynamics and XBeach
for hydrodynamics and morphodynamics assessments. In addition, a comparison
between SWAN and XBeach hydrodynamics results was also performed.
Structures considered in this study have regular shaped geometries, and are characterized in terms of their efficiency regarding wave height and wave energy dissipation considering different wave regimes and performance in terms of longterm beach morphodynamic impact (sediments accumulation and erosion). The
analysis is concentrated in two scenarios, one for low and the other for highly
energetic hydrodynamics (the most challenging to coastal zones defence). The
obtained results allowed classifying their performance in terms of the impact on
wave energy and wave height dissipation, and sediment erosion/deposition patterns.This work is supported by the Portuguese Foundation for Science and Technology
(FCT) [PhD grant number SFRH/BD/141381/2018]. The authors also acknowledge
the support provided by the project EcOffShorBe – Eco Offshore Built Environment,
n. 37417, R&D cores in Copromoção, 14/SI/2017, NORTE-01-0247-FEDER-037417,
supported by ANI (FEDER)
Extreme wave value analysis under uncertainty of climate change scenarios off Iberian Peninsula coast
Extreme wave value analysis under uncertainty scenarios was developed to estimate
wave climate characteristics at 17 stations in southwestern European coast off the
Iberian Peninsula. A comprehensive wave dataset downscaled with the Wave Watch III
(WWIII) model by Meteogalicia under MarRisk Project was used considering results of
models from the Coupled Model Intercomparison Project 5 (CMIP5). Descriptive
statistics for significant wave height (Hs), peak wave period (Tp), and mean and peak
wave direction were performed for historical data (1960−2005), and for projected data
in two twenty-year time periods under two Representative Concentration Pathway
(RCP) scenarios (2026−2045 and 2081−2100). Hs and Tp extreme values for the study
area were obtained using the Gumbel, Fréchet and Weibull probability distributions for
the 10-, 50-, and 100-year return period. Obtained results showed that: historical Hs
values decrease from North to South and are higher than those calculated in any of the
RCPs future scenarios; mean Tp values appear to be constant in all stations; and means
for peak and mean direction have higher frequency of occurrence in Q4 (270°−360°).
This study also allowed the computation of Hs and Tp values for 100-year return period,
which can be used as design criteria for structural analyses in maritime worksThe authors acknowledge the financial support provided by the Portuguese Foundation for Science and Technology (FCT), PhD grant number SFRH/BD/141381/2018. This research was also partially supported by the 0262_MarRISK_1_E project funded by Interreg V-A SpainPortugal Program (POCTEP)
Produção e qualidade de frutos de cultivares de melancia sob irrigação por gotejamento.
Esta pesquisa foi conduzida no Campo Experimental da Embrapa Meio-Norte, Teresina, PI (05°05? S; 42°48?W e 74,4m), com o objetivo de avaliar a produção e qualidade dos frutos de três cultivares de melancia: o híbrido duplo Top Gun, o híbrido triplo Shadow e a cultivar Crimson Sweet, sob irrigação por gotejamento. Aplicou-se uma lâmina de irrigação diária equivalente a 100% de reposição da ET0. O delineamento experimental foi o de blocos casualizados com quatro repetições e duas amostras por parcela. Foram avaliados os seguintes parâmetros: peso médio dos frutos (kg), número de frutos por planta, produtividade (t.ha-1), fator de forma do fruto (dado pela relação entre a largura e o comprimento do fruto), sólidos solúveis totais (ºBrix), pH, conteúdo de vitamina C (mg/100 g de polpa) e acidez total titulável (% ácido cítrico). A cultivar Crimson Sweet apresentou diferença significativa para peso médio dos frutos (6,13 kg) e fator de forma do fruto (0,92), enquanto a cultivar Top Gun apresentou maior conteúdo de vitamina C (6,71 mg/100 g de polpa) e pH (5,21). A produtividade da variedade Crimson Sweet e Top Gun foi influenciada pelo número de frutos por planta
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