Formation of magnetic minerals at hydrocarbon-generation conditions

In this paper, we report the pyrolysis and formation of magnetic minerals in three source rock samples from the Wessex Basin in Dorset, southern England. The experimental conditions in the laboratory recreated the catagenesis environment of oil source rocks. Magnetic analysis of both the heated and the unheated samples at room temperature and at very low-temperatures (5 K), coupled with transmission electron-microscopy imaging and X-ray analysis, revealed the formation of nanometre-sized (<10 nm), magnetic particles that varied across the rock samples analysed, but more importantly across the pyrolysis temperature range. Magnetic measurements demonstrated the formation of these magnetic minerals peaked at 250 °C for all rock samples and then decreased at 300 °C before rising again at 320 °C. The newly formed magnetic minerals are suggested to be primarily pyrrhotite, though magnetite and greigite are also thought to be present. The sizes of the magnetic minerals formed suggest a propensity to migrate together with oil potentially explaining the magnetic anomalies observed above and within oil fields

Agronomic performance of five rapeseed varieties grown for biodiesel in the northeast of Portugal

Rapeseed is an important crop for several European countries and for many others such as Canada and China. Rapeseed oil may have several industrial uses (Sonntag, 1995) and shows excellent properties for the manufacture of biodiesel (Körbitz, 1995). Rapeseed oil may also present high food quality, namely CANOLA (Canadian Oilseed Low-Acid) and European “double-zero” varieties (erucic acid in the oil and glucosinolates in rapeseed cake). World production of rapeseed has quadrupled in the past three decades (FAO, 2013). In Europe the increase in acreage has also been remarkable. Portugal is one of the few European countries where rapeseed is not yet extensively grown. However, field trials carried out in the country (Ferreira, 2009, Rodrigues et al. 2010, Rodrigues et al., 2011) have given good indications on its ecological potential to produce rapeseed if cultivated in the autumn/winter growing season. In the European market there are rapeseed varieties of high vernalisation requirements, suitable for cultivation of rapeseed as an autumn/winter crop, and varieties of smaller vernalisation requirements for cultivation as a spring/summer crop (Guerrero, 1999). In regions benefitting from a Mediterranean climate, rapeseed should be cultivated as an autumn/winter crop in order to mitigate drought problems during spring. In rainfed cropping systems of the Mediterranean region, rapeseed could be an interesting crop to increase the number of the few species that can be included in the crop rotations. In these rotations, rapeseed could be a good preceding crop for wheat since it left a nitrogen-rich residue in the soil (Marquard and Walter, 1995; Arlesa 2011a). If rapeseed is included in irrigated crop rotations, it may validate a double-cropping system, where rapeseed could be grown in winter previously to a second crop in the summer season. The present work aims to assess the potential of five rapeseed cultivars to be grown in rainfed conditions in Northeast of Portugal. These cultivars are being marketed in Spain by Arlesa-Euralis Company and were already grown with relative success in Spain close to the border with Portugal.PROBIOENER – Acción integrada para la promoción e implantación de eficiência energética y energias renovables como factor de competitividad (2009 - 2010

Seeder performance for rapeseed

Rapessed is becoming very interesting mainly due to its importance for biofuels production. In Portugal there is not a great experience with this crop. It is important to get and spread information about all the aspects involved, including mechanical seeding. The seed small size and the necessary low density of seeds per hectare – 3 to 5 kg, impose important specifications to select an adequate seeder. Field trials to evaluate crop and seeder performance were implemented in Northeast of Portugal in autumn 2011 with cultivar ES Hidromel. In this paper we will focus on mechanical seeding. Seeder working time was measured by a chronometer, considering elementary operations like effective seeding time and turning time. Seeder performance is evaluated in hectares per hour. Results are discussed

Cultivo de colza para produção de biodiesel

Cultivo de colza para produção de biodieselO presente trabalho teve como objetivo principal estudar a adaptação da colza às condições de cultivo do Nordeste de Portugal. Procedeu-se ainda à determinação laboratorial do teor de óleo em sementes de colza. A partir de óleos alimentares usados foi produzido biodiesel e determinados os índices de iodo e de acidez, de acordo com as normas EN14111 e EN14104, respetivamente. Aspetos pouco conhecidos sobre a mecanização de operações culturais como a sementeira e colheita foram estudados, tendo-se encontrado algumas respostas para as características que o semeador a eleger deve conter e regulações a efetuar na ceifeira- -debulhadora a usar na colheita. A produção de colza em campo foi bastante penalizada pelas condições de seca severa que se registaram no Inverno e início da Primavera desse mesmo ano, não tendo sido possível observar efeitos significativos entre as diferentes modalidades experimentais. A produção média de colza em cada um dos talhões foi da ordem de 1000 kg semente ha-1. O teor em óleo das sementes de colza variou entre 41.7 e 42.0%. Relativamente ao índice de acidez do biocombustível obteve-se 0.16 g KOH/g amostra e quanto ao índice de iodo registou-se o valor de 130.32 g iodo/100 g de biocombustível

Response of rapeseed to nitrogen fertilisation in a mediterranean environment

Portugal needs urgently to increase the production of vegetable oils to be able to meet the mandatory 10% minimum target to be achieved by all member states for the share of biofuels in transport petrol and diesel consumption by 2020 (Directive 2009/28/EC). Rapeseed oils the main raw material used in Europe for the manufacture of biofuels. Portugal, however, does not produce rapeseed oil, in spite of some studies have indicated that there are favourable ecological conditions to do that around the country [I, 2]

A colza pode dinamizar o setor arvense de sequeiro

Portugal necessita de incorporar 10% de biocombustíveis nos combustíveis convencionais até 2020. Tudo indica que se estas metas forem atingidas, sê-lo-ão à custa da importação das matérias- primas. A colza pode ajudar a mitigar o problema, na medida em que atinge produtividades interessantes em sequeiro. A técnica cultural é muito semelhante à dos cereais de inverno, o que facilita a sua inclusão nos sistemas de cultivo. Os produtores de cereais devem começar a equacionar a inclusão da colza nas suas rotações de sequeiro

Renal dysfunction in patients with sickle cell anemia or sickle cell trait

Patients with sickle cell anemia (Hb SS) or sickle cell trait (Hb AS) may present several types of renal dysfunction; however, comparison of the prevalence of these abnormalities between these two groups and correlation with the duration of disease in a large number of patients have not been thoroughly investigated. In a cross-sectional study using immunoenzymometric assays to measure tubular proteinuria, microalbuminuria, measurement of creatinine clearance, urinary osmolality and analysis of urine sediment, we evaluated glomerular and tubular renal function in 106 adults and children with Hb SS (N = 66) or Hb AS (N = 40) with no renal failure (glomerular filtration rate (GFR) >85 ml/min). The percentage of individuals with microalbuminuria was higher among Hb SS than among Hb AS patients (30 vs 8%, P85 ml/min).A01Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

On infinite walls in deformation quantization

We examine the deformation quantization of a single particle moving in one dimension (i) in the presence of an infinite potential wall, (ii) confined by an infinite square well, and (iii) bound by a delta function potential energy. In deformation quantization, considered as an autonomous formulation of quantum mechanics, the Wigner function of stationary states must be found by solving the so-called \*-genvalue (``stargenvalue'') equation for the Hamiltonian. For the cases considered here, this pseudo-differential equation is difficult to solve directly, without an ad hoc modification of the potential. Here we treat the infinite wall as the limit of a solvable exponential potential. Before the limit is taken, the corresponding \*-genvalue equation involves the Wigner function at momenta translated by imaginary amounts. We show that it can be converted to a partial differential equation, however, with a well-defined limit. We demonstrate that the Wigner functions calculated from the standard Schr\"odinger wave functions satisfy the resulting new equation. Finally, we show how our results may be adapted to allow for the presence of another, non-singular part in the potential.Comment: 22 pages, to appear in Annals of Physic

A novel hybrid material with calcium and strontium release capability

The preparation of PDMS–TEOS–CaO hybrid materials by sol–gel techniques has been widely described in previous works. Calcium nitrate is the most common source of calcium used in these preparations. However, to remove possible toxic nitrate by-products a thermal treatment is necessary at temperatures above 500 1C, which leads to the degradation of the polymeric components of the hybrids. Strontium has already shown some promising results in the therapeutic area, being used in cases of osteoporosis and low bone density. In this study a new potential bioactive hybrid material was prepared, by sol–gel techniques, using calcium acetate as a novel calcium source. Also, for the first time, incorporation of strontium in a PDMS–TEOS hybrid system was evaluated. Samples were characterized before and after immersion in Kokubo’s Simulated Body Fluid (SBF) by SEM, EDS, ICP and FT-IR spectroscopy

Diagnóstico do estado nutritivo de uma plantação jovem de olival

Na Primavera de 2009 foi instalado em S. Pedro Vale do Conde, em Mirandela, um olival em duas densidades 4 x 1,35 m e 7 x 3,5 m. Na densidade 4 x 1,35 m foram instaladas três cultivares: Cobrançosa, Negrinha e Arbequina. Na densidade 7 x 3,5 m foram instaladas as cultivares: Cobrançosa, Madurai e Verdeal Transmontana. O olival foi instalado num solo franco-arenoso, com 1% de matéria orgânica e pH em água de 4,3. No Verão seguinte à instalação iniciou-se a monitorização do estado nutritivo das plantas através de análise foliar efetuada duas vezes ao ano, em julho e janeiro. A concentração de azoto nas folhas revelou elevada variação nas duas primeiras datas de amostragem, com estabilização dos valores na gama de concentrações adequadas a partir do segundo ano. Não foram registadas diferenças significativas entre cultivares. Os valores de fósforo e potássio revelaram-se com bastante variabilidade, com tendência para estabilizarem dentro da gama de concentrações adequadas. A concentração de cálcio nas folhas manteve-se abaixo do limite critico de deficiência refletindo o pH particularmente baixo do solo. Os valores de magnésio também se mantiveram baixos, frequentemente abaixo do limite de concentrações críticas de deficiência. O boro revelou elevada diferença entre as amostragens de Verão e de Inverno, aspeto característico deste elemento, com valores mais altos no Verão. A Madurai parece manter valores estatisticamente mais elevados que as restantes cultivares. Apesar da Importância da monitorização do estado nutritivo das plantas nas fases juvenis, a elevada variabilidade encontrada parece dificultar a definição da melhor estratégia de fertilização