1,520 research outputs found
Removal of polycyclic aromatic hydrocarbons by biosorbents
Introduction: - Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental carcinogens. They are formed during the
incomplete combustion of organic matter. Humans are exposed to PAHs by various sources, including occupational
environments, cigarette smoke, vehicle exhaust, and dietary sources as grilled and flame-broiled food.
- In vivo studies in animals proved that PAHs are associated to cancer, and epidemiologic studies with exposed
workers, especially in coke ovens and aluminium smelters, have shown clear excess of lung cancer and highly
suggestive excesses of bladder cancer.
- These compounds can enter in drinking water sources by precipitation and runoff on the earth’s surface.
- Portuguese legislation for water for human consumption (DL 306/2007) proposes the determination of five PAHs;
limits of the maximum concentration are 0.10 µg/L for total BghiP, BbF, BkF, IcdP, and 0.010 µg/L for BaP.This work was financial suported by the COMPETE program, under the Watercork project
(nº. 2009/552).N/
Vacuum polarization by a global monopole with finite core
We investigate the effects of a -dimensional global monopole core on
the behavior of a quantum massive scalar field with general curvature coupling
parameter. In the general case of the spherically symmetric static core,
formulae are derived for the Wightman function, for the vacuum expectation
values of the field square and the energy-momentum tensor in the exterior
region. These expectation values are presented as the sum of point-like global
monopole part and the core induced one. The asymptotic behavior of the core
induced vacuum densities is investigated at large distances from the core, near
the core and for small values of the solid angle corresponding to strong
gravitational fields. In particular, in the latter case we show that the
behavior of the vacuum densities is drastically different for minimally and
non-minimally coupled fields. As an application of general results the
flower-pot model for the monopole's core is considered and the expectation
values inside the core are evaluated.Comment: 22 pages, 4 figures, misprint is corrected, discussion is added,
figures are change
Infestação entomológica e estimativa do risco de lepidópteros numa moagem de trigo em Cabo Verde
An insect species list associated to a flour mill in Cape Verde was presented. The possible factors responsible
for the differences observed in the different locations within the flour mill were discussed. Results obtained in
1999 were compared with data recorded in 1984 in identical conditions inside this flour mill. During two years
the risk estimate from Lepidoptera infestations was carried out in this flour mill using pheromone traps. The
number of adults captured in the pheromone traps recorded weekly within two years, indicated the places
with higher infestation levels and allowed to estimate the risk assessment and to make decisions for
controlling and planning clean actions against Ephestia cautella and E. kuehniella
Adopção de protecção integrada em tabaco armazenado em Portugal
Lasioderma serricorne (F.) and Ephestia elutella (Hb.) are the most serious pests of stored tobacco. Mainly are the
larvae that feed on the product, may contaminate it with their excreta and cause damage on tobacco and
allergic responses.
The present work evaluated cigarette beetles and tobacco moths’ populations from the tobacco fields to the
processing factories in Portugal using pheromone traps.
Density, dispersion, risk assessment and the efficacy of making decisions based on economic thresholds were
evaluated. For L. serricorne, the efficacy of mass-trapping using pheromone traps was studied. Sequential
sampling for risk assessment was developed for processed tobacco and in a cigarette factory.
These studies pretended to contribute for the integrated pest management of stored tobacco and also for the
stored products in general, as the methodologies applied, with some adaptations, can be used for other pests
and stored products
The impact of oligomeric anions on the speciation of protic ionic liquids
The synthesis of protic ionic liquids based in carboxylate anions, too often admitted as being straightforward, is actually challenging and must be carefully addressed. This review discusses the importance of oligomeric anions, in particular those based on carboxylates, in the behavior and nature of protic ionic liquids. There is strong evidence in the literature that the synthesis, and subsequent purification, of protic ionic liquids involving carboxylic acids, leads to structures in the liquid phase with an acid:base proportion different from the expected 1:1 stoichiometry. The formation of the oligomeric anions, mostly dependent on the proton transfer from the Brønsted acid to the Brønsted base, may lead to a higher ionicity that suggests the formation of true ionic liquids. It is here stressed the relevance of deepening the understanding of the interactions between the species and the speciation of the liquid phase, combining experimental and theoretical approaches to establish foundations for insightful advances in the area.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020 , CIMO-Mountain Research Center, UIDB/00690/2020 , and CIQUP, University of Porto (Projects: PEstUID/QUI/00081/2013 ) financed by national funds through the Portuguese Foundation for Science and Technology (FCT) /MCTES. This work was also developed within the scope of the Indo- Portuguese Program for Cooperation in Science & Technology DST/INT/Portugal/P-01/2017 , financed by FCT and the Government of India. P.J.C. acknowledge FCT for his contract under the Investigator FCT 2015 contract number IF/00758/2015 .info:eu-repo/semantics/publishedVersio
Abundance and diversity of potential vectors of Xylella fastidiosa in four different wine regions of Portugal
Xylella fastidiosa, is a phytopathogenic bacterium, responsible for serious diseases in important
crops, such as Pierce’s Disease in grapevines. The recent detection of this bacterium in Portugal
is worrying, since this bacterium can spread rapidly via xylem-sap feeder insects, mainly belonging
to Hemiptera Cicadomorpha. In this context, the goal of this work was to detect the abundance and
diversity of possible vectors of X. fastidiosa in vineyards from different wine regions of Portugal. For
that, in 2018, 21 vineyards with ground cover and from four different wine regions of Portugal (i.e.,
“Trás-os-Montes”, “Vinho Verde”, “Bairrada”, and “Peninsula de Setúbal”) were sampled for adults of
Auchenorrhyncha, during three distinct periods (beginning of July, mid September and mid October).
Sampling was performed in the ground and in the aerial part of the vines. In each sampling date,
10 samples of 10 sweepings were collected on the ground in each vineyard. On the aerial part of
the vines, 10 samples of 50 sweepings were collected in 3 lines of the vineyard. A total of 3543
Cicadomorpha were collected on the 3 sampling dates, being the highest abundance observed in
the mid September. The “Trás-os-Montes” and “Bairrada” regions, in general, presented the highest
abundance of insects of this infraorder, but it was in “Vinho Verde” region that there was a highest
abundance of potential vectors: Philaenus, Neophilaenus and Cicadelli viridis.Work funded by the project H2020-SFS-2016-3. RIA, contrato 727987 “XF-ACTORS: Xylella
fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy”.info:eu-repo/semantics/publishedVersio
Variação espacial de propriedades físicas e químicas do solo em olivais de Trás-os-Montes
A introdução de novos sistemas de gestão da vegetação herbácea em olivais de
Trás-os-Montes tem realçado o interesse em conhecer os efeitos produzidos na
variabilidade espacial das propriedades do solo. Com o presente trabalho pretende-se
avaliar o efeito de diferentes sistemas de gestão do coberto vegetal herbáceo em
olivais na distribuição espacial de propriedades físicas e químicas do solo. O estudo
decorreu em nove olivais com os seguintes sistemas de gestão do solo: (MT) solo nu ao
longo de todo o ano, com recurso à mobilização tradicional; (HB) cobertura do solo por
vegetação natural, com controlo efetuado por aplicação de herbicidas na linha de
plantação (LP) e destroçamento da vegetação seca na entrelinha (EL); (LS) cobertura
do solo por espécies de leguminosas semeadas, com controlo efetuado por pastoreio e
posterior destroçamento da vegetação seca e (VN) cobertura do solo por vegetação
natural. Em cada olival foram selecionados 16 locais (8 na LP e 8 na EL), onde se
procedeu à colheita de amostras de solo perturbadas e não perturbadas na
profundidade 0-5 cm. Foram determinados vários parâmetros físicos e químicos do
solo e calculou-se índices de enriquecimento (IE). Os olivais que utilizam coberturas
vivas apresentam acumulação de resíduos orgânicos à superfície, sendo esta sempre
superior na LP, o que conduz a teores de matéria orgânica superiores e com
distribuição espacial mais homogénea comparativamente aos olivais mobilizados. Em
concordância com esta observação, a densidade aparente é menor na LP apresentando
variabilidade espacial inferior nos olivais com leguminosas semeadas. Os nutrientes do
solo não apresentam uma tendência consistente com o sistema de gestão do solo, mas
de um modo geral, os olivais com coberto de leguminosas tendem a apresentar maior
homogeneidade espacial.The introduction of management systems for the herbaceous vegetation in
olive grove from Trás-os-Montes has been stressing the interest for the knowledge
about the effects caused to the spatial variability of soil properties. The objective of
this work is to evaluate the effect of different management systems of herbaceous
ground covers in the different spatial physical and chemical soil properties of the olive
grove. The study took place in nine olive groves that have been managed with the following systems: (1) naked soil due to mobilization; (2) soil covered by natural
vegetation controlled by herbicides on the plantation row and dried vegetation broken
into pieces on the row between the trees; (3) soil covered by sown leguminous,
controlled by grazing and (4) soil covered by natural vegetation. In each olive grove, 16
places (eight in the plantation row and eight in the row between the trees) were
selected and disturbed and undisturbed soil samples were collected at 0-5 cm depth.
Several physical and chemical soil parameters were calculated as well as the
enrichment index (IE). Results showed that the olive groves with soil covers
accumulated organic materials on the surface, reaching higher values in the plantation
row, and producing higher levels of organic matter with more homogeneous spatial
distribution when compared with mobilized groves. In agreement with this
observation, the apparent density is lower in the plantation row showing an inferior
spatial variability in the olive groves covered by sown leguminous. Soil nutrients did
not show a consistent trend with the soil management system but, in a general way,
the olive groves covered by sown leguminous had a tendency to present higher spatial
homogeneity
Selecting Critical Properties of Terpenes and Terpenoids through Group-Contribution Methods and Equations of State
The knowledge of critical properties is fundamental in engineering process calculations for the estimation of thermodynamic properties and phase equilibria. A literature survey shows a large number of methods for predicting critical properties of different classes of compounds, but no previous study is available to evaluate their suitability for terpenes and terpenoids. In this work, the critical properties of terpenes and terpenoids were first estimated using the group-contribution methods of Joback, Constantinou and Gani, and Wilson and Jasperson. These were then used to calculate densities and vapor pressure through the equations of state Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) and then compared with the experimental values. On other hand, density and vapor pressure experimental data were used to estimate the critical properties directly by the same equations of state (EoSs), allowing a comparison between the two estimation procedures. For this purpose densities for 17 pure terpenes and terpenoids were here measured at atmospheric pressure in the temperature range (278.15 to 368.15) K. Using the first approach, the best combination is the Joback's method with the Peng-Robinson EoS, despite the high relative deviations found for vapor pressure calculations and difficulties to predict density at low temperatures. Following the second approach, the set of critical properties and acentric factors estimated are able to adequately correlate the experimental data. Both equatio ns show a similar capability to correlate the data with SRK EoS presenting a global %ARD of 3.16 and 0.62 for vapor pressure and density, respectively; while the PR EoS presented 3.61 and 0.66, for the same properties, both giving critical properties estimates also closer to those calculated by the Joback method, which is the recommended group-contribution method for this type of compounds.This work was developed in the scope of the projects POCI-01-
0145-FEDER-007679-CICECO-Aveiro Institute of Materials
(ref. FCT UID/CTM/50011/2013), POCI-01-0145-FEDER-
006984−Associate Laboratory LSRE-LCM both funded by
European Regional Development Fund (ERDF) through
COMPETE2020, Programa Operacional Competitividade e
Internacionalização (POCI), and by national funds through
FCT (Fundação para a Ciência e a Tecnologia). This work is
also a result of project “AIProcMat@N2020 (Advanced
Industrial Processes and Materials for a Sustainable Northern
Region of Portugal 2020)”, with the reference NORTE-01-
0145-FEDER-000006, supported by Norte Portugal Regional
Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through ERDF. M.A.R.M.
acknowledges FCT for her Ph.D. grant (SFRH/BD/87084/
2012) and COST for the STSM Grant from COST action
CM1206. P. J. Carvalho also acknowledges FCT for a contract
under the Investigador FCT 2015, Contract No. IF/00758/
2015. A.M.P. acknowledges Infochem-KBC for his Ph.D. grant.
The software Multiflash from Infochem-KBC was applied in
some of the calculationsinfo:eu-repo/semantics/publishedVersio
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