2,945 research outputs found
Accelerometers can measure total and activity-specific energy expenditures in free-ranging marine mammals only if linked to time-activity budgets
Peer reviewedPostprin
Direct Diode Lasers for Industrial Laser Cutting: A Performance Comparison with Conventional Fiber and CO2 Technologies
AbstractThe direct use of diode lasers for cutting sheet metal has high potential to decrease operational costs, but, currently, implementation in industrial environments is constrained by beam quality. In this paper the performance of a novel direct diode laser (DDL) with increased beam quality is documented for both fusion and flame cutting and compared to conventional CO2 and fiber laser sources. Experimental tests were carried out for steel and aluminium based on a Design of Experiments approach. Furthermore, an analytical model, focusing on the absorption of lasers in metals, is described here, which predicts and clarifies performance variation. Although the observed laser beam quality is still lower than the other studied technologies, industrially relevant cutting speeds, with acceptable surface quality, are achievable with DDL, as validated by our result
Turbine and exhaust ports thermal insulation impact on the engine efficiency and aftertreatment inlet temperature
[EN] Worldwide emission regulations are driven the efforts of the automotive industry to meet challenging targets concerning pollution reduction. Nowadays, advances in exhaust aftertreatment systems are primarily required to achieve regulation requirements within the whole engine operating range. Nevertheless, flow parameters, such as the exhaust gas temperature, must be also addressed. This makes engine calibration a fundamental step, but also leads to reconsider the passive design of the exhaust line as a way to improve the engine efficiency. Under this context, a study has been conducted to explore the benefits of heat losses limitation looking for aftertreatment inlet temperature increase at the same time fuel economy is improved. To do so, a baseline diesel engine has been modeled using a gas dynamic software taking special care of the heat transfer processes in the exhaust. The investigation covers the definition of different strategies for exhaust ports and turbine thermal insulation, which are evaluated in a representative range of steady-state operating conditions. As a first step, the theoretical limits and representative technology solutions are considered for each exhaust region. Then, a combination of the most promising strategies has been computed to provide a comprehensive database and analysis of the potential of passive exhaust heat losses control.This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R. Additionally, the Ph.D. student Bárbara Diesel has been funded by a grant from the Government of Generalitat Valenciana with reference ACIF/2018/109.Luján, JM.; Serrano, J.; Piqueras, P.; Diesel Costa, B. (2019). Turbine and exhaust ports thermal insulation impact on the engine efficiency and aftertreatment inlet temperature. Applied Energy. 240:409-423. https://doi.org/10.1016/j.apenergy.2019.02.043S40942324
First report of a norovirus outbreak associated with the variant Sydney 2012 in Portugal
Introduction: This study describes the investigation of a gastroenteritis outbreak in a group of students, associated with a dinner reunion in February 2013 in Porto, Portugal.
Methodology: An anonymous structured questionnaire was developed and sent to 34 students who attended the dinner reunion. Eighteen students completed the questionnaire and thirteen met the case definition (attack rate of 72%). Stools from two students were screened for norovirus by RT-PCR using primer pairs that target the highly conserved polymerase gene and the capsid gene.
Results: Norovirus genotyping confirmed the variant Sydney 2012 as the probable cause of the outbreak.
Conclusion: This is the first report of an outbreak associated with the new variant Sydney 2012 in Portugal.The study was supported by FEDER funds through Programa Operacional Factores de Competividade (COMPETE), by national funding through Fundação para a Ciência e a Tecnologia (FCT) (project PTDC/CVT/113218/2009), and by grant SFRH/BD/45407/2008, and by project Ovislab ICT-2013-05-004-5314 ID-64757
Bentonite functionalized with propyl sulfonic acid groups used as catalyst in esterification reactions
AbstractThe main objective of this work is the functionalization of bentonite from the Amazon (region) by the grafting of propyl sulfonic acid groups to catalyze the esterification reaction of acetic acid and 1-propanol. Functionalization was accomplished by anchoring, oxidation and acid activation of (3-mercaptopropyl)trimethoxysilane, (MTPS). The procedure gave acid properties to the raw bentonite. This material, acting as a catalyst, increased the reaction speed and improved the yield by about 12% compared to the uncatalyzed reaction. The functionalized bentonite was characterized by XRD, TG/DTA, FTIR, N2 adsorption/desorption at 77K and XRF, and the surface acidity was determined by titration
Adubação não radicular com duas fontes de zinco em Coffea arábica L. "mundo novo" (B.Rodr.) Choussy
A trial was carried out on an eight old coffee plantation with visible zinc problems. The plantation was situated nearly the city of Jaú (22º30'S, 48º30'W). State of São Paulo, Brazil. The soil is classified as medium texture Oxisol of low base saturation (Latossol Vermelho Amarelo - fase arenosa). The pulverization program started in november 1977, followed in march and July 1978 (heavy harvest) and ended in march and July 1979 (light harvest). Is should be mentioned that a well reconized characteristic of arábica coffe is its habit of biennial bearing, a very heavy harvest is most often followed by a light load the next year. The following treatments and amounts of chemicals per cova hole (4 trees) were tested in accordance with a random block design: 1. 1 g of zinc (zinc sulphate, 0.5%) 2. 3 g of nitrogen (urea, 1.3%) 3. 1 g of zinc + 3 g of nitrogen (zinc sulphate 0.5% + urea 1.3%) 4. 0.25 g, 0.50 g, 1.00 g, 2.00 g of zinc plus 0.75 g, 1.50 g, 3.00 g and 6.00 of nitrogen (correspondent to NZN* 15-0-0-5 as 0.75%, 1-5%, 3.0% and 6.0% by v/v). Foliar absorption data were obtained by collecting the 3rd and 4th pairs of the coffee leaves and analysed them for N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn. The main results may be summarized as follows: 1. The maximum calculated yields of clean coffee were obtained by the applications of 5.84 1 of NZN (1.13%) per hectare. 2. The applications of zinc sulphate (0.5%) and urea (1.3%) together or separate did not affected the coffee bean production. 3. The applications of 15.0 1 of NZN per hectare reduced the coffee yields. 4. Leaf damages and burning symptoms were observed by the applications of urea (1.3%) plus zinc sulphate (0.5%) and larger doses than 7.5 1 of NZN per hectare. 5. Leaf tissue analysis show that the concentrations of the elements were affecred by the age of the leaves and by the yields of the coffee trees. 6. The applications of increasing doses of NZN causes an increase in the concentration of zinc, manganese and boron in the leaves and decreased the concentration in calcium and potassium the leaves. 7. The concentration of zinc in the leaves associated with the heavy harvest, in July, was 70.0 ppm.Em cafezal com 8 anos de idade, com deficiência visível de zinco, situado em um Latossol Amarelo - fase arenosa, do município de Jaú, SP, procederam-se pulverizações em novembro, março e julho de 1978 (grande safra) e março e julho de 1979 (pequena safra), O delineamento experimental foi de blocos ao acaso e constou dos seguintes tratamentos, nas doses por planta: lg de zinco (sulfato de zinco 0,5%), 3g de nitrogênio (uréia 1,3%), lg de zinco + 3g de nitrogênio (sulfato de zinco 0,5% + uréia 1,3%) e 0,25g, 0,50g, 1 ,00g e 2,00g de zinco juntamente com 0,75g, l,50g, 3,00g e 6,00g de nitrogênio (respectivamente NZN 15-0-0-5 * a 0,75%, 3,00% e 6,00% v/v). Na época das pulverizaçoes foram coletadas amostras de 3º e 4º pares de folhas, e determinados os teores de nitrogênio, fósforo, potássio, cálcio, magnésio, boro, cobre, ferro, manganês e zinco. Os resultados mostraram que: a) a produção máxima calculada de café beneficiado foi 3-009,4 kg/ha, obtida com pulverizaçao de 5,84 1 de NZN por hectare (NZN 1 ,17%) ; b) o sulfato de zinco e a uréia, juntos ou isoladamente, não afetaram a produção; c) a dose de 15,0 1 de NZN por hectare diminuiu a produção; d) as aplicações de uréia (1,3%) + sulfato de zinco (0,5%) e de doses de NZN superiores a 7,51/ha provocaram injúrias visíveis nas folhas. Esse efeitos se agravaram com dosagens de 15 1 e 30 1 de NZN por hectare; e) as concentrações dos nutrientes nas folhas foram afetadas de maneira diferente pelas épocas de amostragem e pela produção do cafeeiro; f) a aplicação de doses crescentes de NZN provocou aumento nas concentrações de zinco, manganês e boro e diminuição nas de cálcio e potássio nas folhas, em determinadas épocas da grande ou pequena safra; g) a concentração de zinco em julho, relacionada com a maior produção do cafeeiro, foi 70 ppm
Analysis of the Driving Altitude and Ambient Temperature Impact on the Conversion Efficiency of Oxidation Catalysts
[EN] Worldwide emission standards are extending their requirements to cover engine operation under extreme ambient conditions and fill the gap between the type-approval and real driving conditions. The new ambient boundaries affect the engine performance and raw emissions as well as the efficiency of the exhaust aftertreatment systems. This study evaluates the impact of high altitude and low ambient temperature on the light-off temperature and conversion efficiency of an oxidation catalyst. The results are compared in a common range of exhaust mass flow and temperature with the baseline sea-level operation at 20 degrees C. A reduction of CO and HC conversion efficiencies was found at 2500 m and -7 degrees C, with a relevant increase of the light-off temperature for both of the pollutants. The analysis of the experimental data was complemented with the use of a catalyst model to identify the causes leading to the deterioration of the CO and HC light-off. The use of the model allowed for identifying, for the same exhaust mass flow and temperature, the contributions to the variation of conversion efficiency caused by the change in engine-out emissions and tailpipe pressure, which are, in turn, manifested in the variation of the reactants partial pressure and dwell time as governing parameters.This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R. Additionally, the PhD candidate Barbara Diesel has been funded by a grant from the Government of Generalitat Valenciana and FSE (European Union) with reference ACIF/2018/109.Serrano, J.; Piqueras, P.; Sanchis-Pacheco, EJ.; Diesel Costa, B. (2021). Analysis of the Driving Altitude and Ambient Temperature Impact on the Conversion Efficiency of Oxidation Catalysts. Applied Sciences. 11(3):1-21. https://doi.org/10.3390/app11031283S12111
Soybean DNA extraction from blended refined vegetable oils
The major genetically modified (GM) crop species is soybean (Glycine max), accounting for 53% of the total world’s GM planted area and 70% of the soybean annual production in 2008 [1]. Since the approval of Roundup Ready® (RR) soybean in EU, the production of soybean oil using GM seeds has been increasing. In EU, the doubts raised by the use of genetically modified organisms (GMO) lead to the mandatory labelling for food products containing more than 0.9% of authorised GMO. In blended edible oils prepared with mixtures of two or more different oils, it is important to verify the labelling statements concerning their constituents and the presence of GM material, since soybean oil is frequently used. The analysis of DNA coupled with polymerase chain reaction (PCR) has been the technique of choice to monitor the presence of GMO in food. However, it is very difficult to obtain amplifiable DNA from oil since most vegetable oils, like crude soybean oil, must be refined prior to its consumption
Assessing the effect of pharmaceutical excipients on the DNA extraction from plant food supplements
in the EU market as ingredients in formulations, which are sold as plant food supplements
(PFS). Among the several issues that may affect the safety of PFS, the most relevant
concerns aduÍterations by the illegal addition of pharmaceutical drugs and/or the swap/
misidentification ofplant material, with cases of acate toxicity already reported [l]. Owing
to the high similarity and distinct therapeutic uses ofseveral medicinal plants, accurate and
fast methodologies allowing their distincüon are required. For that purpose, DNA-based
methods are considered fast, sensitive and highly specific tools, allowing the unequivocal
identification of plant species. Up to date, most of DNA methodologies reporting the
identification of plant species essentially concern medicinal plants [2], with few works
being developed for the authentication of PFS.This work was supported by the projects EXPL/DTP-SAP/1438/2013 (4SaferPFS)
and Pest-C/EQB/LA0006/2013 financed by FCT (Fundação para a Ciência e Tecnologia) (FEDER funds
through COMPETE). Teimo J.R. Fernandes is grateful to FCT PhD grant (SFRH/BD/93711/2013) financed
by POPH-QREN (subsidised by FSE and MCTES).info:eu-repo/semantics/publishedVersio
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