THE EFFECT OF TEMPERATURE IN TETRADESMUS OBLIQUUS

The ever growing demand of energy generation and distribution has been one of the concerns of governments and the focus of research institutions.  Likewise, how to supply the energy demands necessary for the development of nations having the lowest environmental impact possible has also been studied. Biofuels have been pointed out as an alternative for that energy challenge, since their use reduce the carbon footprint of industries and vehicles. Biofuels can be obtained from microalgae with the advantage of not competing for space with corn, sugar cane or other crops for food industry. Even though attractive, the biofuel production from microalgae presents some challenges, as for example the separation process required to obtain microalgae biomass. The culture is very diluted and the dewatering must be efficient, low cost and cause no damage to the cell. With the intent to address this issue, the herein paper presents a study of an alternative way to increase flocculation efficiency according to the temperature of the culture with the potential to improve the filtration efficiency in a continuous process. An increasing in the flocculation temperature from 20°C to 60°C increased the flocculation efficiency from 97.79% to 98.64%, using ferric chloride as a flocculant agent

Observation of Dirac surface states in the noncentrosymmetric superconductor BiPd

Funding from the MPG-UBC center and the Engineering and Physical Sciences Research Council (EP/I031014/1 and EP/L505079/1) are acknowledged. This work was supported by the DFG within projects STA315/8-1 and BE5190/1-1.Materials with strong spin-orbit coupling (SOC) have in recent years become a subject of intense research due to their potential applications in spintronics and quantum information technology. In particular, in systems which break inversion symmetry, SOC facilitates the Rashba-Dresselhaus effect, leading to a lifting of spin degeneracy in the bulk and intricate spin textures of the Bloch wave functions. Here, by combining angular resolved photoemission (ARPES) and low temperature scanning tunneling microscopy (STM) measurements with relativistic first-principles band structure calculations, we examine the role of SOC in single crystals of noncentrosymmetric BiPd. We report the detection of several Dirac surface states, one of which exhibits an extremely large spin splitting. Unlike the surface states in inversion-symmetric systems, the Dirac surface states of BiPd have completely different properties at opposite faces of the crystal and are not trivially linked by symmetry. The spin-splitting of the surface states exhibits a strong anisotropy by itself, which can be linked to the low in-plane symmetry of the surface termination.PostprintPeer reviewe

Mapping of Submerged Aquatic Vegetation in Rivers From Very High Resolution Image Data, Using Object Based Image Analysis Combined with Expert Knowledge

The use of remote sensing for monitoring of submerged aquatic vegetation (SAV) in fluvial environments has been limited by the spatial and spectral resolution of available image data. The absorption of light in water also complicates the use of common image analysis methods. This paper presents the results of a study that uses very high resolution (VHR) image data, collected with a Near Infrared sensitive DSLR camera, to map the distribution of SAV species for three sites along the Desselse Nete, a lowland river in Flanders, Belgium. Plant species, including Ranunculus aquatilis L., Callitriche obtusangula Le Gall, Potamogeton natans L., Sparganium emersum L. and Potamogeton crispus L., were classified from the data using Object-Based Image Analysis (OBIA) and expert knowledge. A classification rule set based on a combination of both spectral and structural image variation (e.g. texture and shape) was developed for images from two sites. A comparison of the classifications with manually delineated ground truth maps resulted for both sites in 61% overall accuracy. Application of the rule set to a third validation image, resulted in 53% overall accuracy. These consistent results show promise for species level mapping in such biodiverse environments, but also prompt a discussion on assessment of classification accuracy

Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans

Postprint4,411

Gating Current flowing through Molecules in Metal-Molecules-Metal Junctions

We have assembled two junctions that incorporate redox sites between Hg electrodes by different interactions. In the first junction, Hg-SAM-R//R-SAM-Hg, the redox site (R) are covalently linked to each electrode in self assembled monolayers (SAM-R). In the second junction, Hg-SAM//R//SAM-Hg, the redox sites dissolved in solution are trapped by electrostatic interaction at the SAM formed at the electrodes. The current flowing through these junctions can be controlled by adjusting the potential applied at the electrodes respect to the redox potential of the species by using an electrochemical system. The current flowing in these two junctions is mediated by the redox sites through different mechanisms. In particular, the current flowing through junction Hg-SAM-R//R-SAM-Hg occurs through a self exchange mechanism between the redox sites organized at each electrode, while the current flowing through junction Hg-SAM//R//SAM-Hg is dominated by a redox- cycling mechanism. The systems described here are easy to assemble, well-characterized, yield reproducible data and make it easy to modify the electrical properties of the junctions by changing the nature of the redox centres. For these characteristics they are well suited for collecting fundamental information relevant to the fabrication of molecular switches

Concorso per il Parco urbano del Porto Navile e della Manifattura Tabacchi a Bologna

Pubblicato in: Aa. Vv., Il Labirinto. Centotrentotto idee progettuali per il parco urbano del Porto Navile e della Manifattura Tabacchi, Comune di Bologna-Assessorato alla Progettazione e attuazione, Grafis Edizioni, Bologna 1985. Esposto in occasione della mostra: Il Labirinto. Centotrentotto idee progettuali per il parco urbano del Porto Navile e della Manifattura Tabacchi, Bologna 198

Controlling the Electron Transfer Mechanism in Metal-Molecules-Metal Junctions

We show how the mechanism of electron transfer through molecules can be switched between different regimes by using a simple Hg-based metal-molecules-metal junction that allows for hosting of self-assembled monolayers (SAMs) of a large variety of molecular systems. We compare here the results obtained by using two different approaches in measuring electron transfer rate. Using a two-electrode assembly we have measured I-V curves through SAMs formed by different organic molecules (alkanethiols HS(CH2)n-1CH3 (n = 8, 10, 12, 14, 16), oligophenylene thiols HS(C6H4)kH (k = 1, 2, 3), or benzylic homologs of the oligophenylene thiols HSCH2(C6H4)mH (m = 1, 2, 3). The molecules incorporated have a very large HOMO-LUMO energy separation and their orbitals cannot align with the Fermi levels of the electrodes under an applied voltage. The molecules therefore behave as insulators, and the electron transport mechanism is characterized by a through-bond tunneling process. Using an electrochemical junction we have measured I-V curves through SAMs of molecules incorporating redox sites (ruthenium pentaamine pyridine-terminated thiol [HS(CH2)10CONHCH2pyRu(NH3)5](PF6)2). The incorporated redox sites have energetically low molecular orbitals which can align with the Fermi levels of the electrodes. A four-electrode configuration of the electrochemical junction allows control of the potentials of the electrodes with respect to the redox potential of the incorporated redox-active molecules. We show that under this control of potential the electron transport mechanism can be switched to different regimes and the current flowing through the junction can be modulated

Azobenzenes as Light-controlled Molecular Electronic Switches in Nanoscale Metal-Molecule-Metal Junctions

Self-assembled monolayers (SAMs) of azo-biphenyl derivatives AZO1 have been ssembled on gold surfaces and electrocally tested under irradiation. Comparable maximal cis/trans ratios of ca. 0.9 have been observed in all cases upon irradiation at λ = 370 nm and λ = 360 nm. The current values measured by STM on the two isomers indicate a largere current for the cis isomer respet to the trans isomer, in agreement with the theory