Low-latency privacy-enabled Context Distribution Architecture

As personal information and context sharing applications gain traction more attention is drawn to the associated privacy issues. These applications address privacy using an unsatisfactory {"}whitelist{"} approach [1] [2], similar to social networks {"}friends{"}. Some of them also link location publishing with user interaction which is also a form of privacy control - the user has to explicitly say where he is. There are a few automatic location based-services (LBS) that track the user [3], but without more adequate privacy protection mechanisms they enable even bigger threats to the user. On previous work, an XMPP-based Context Distribution Architecture was defined [4], more suitable for the distribution of frequently changing context than other systems because it is based on the publish-subscribe pattern. In this paper the authors present an extension to this architecture that allows for the introduction of a complex degree of access control in context distribution. The devised changes enable the system to consider a number of interesting context privacy settings [1] for context distribution control. Also, this control must be enforced in a way that it doesn't interfere with the real-time nature of the distribution process. After describing the enhancements to the architecture, a prototype of the system is presented. Finally, the delivery latency and additional processing introduced by the access control components is estimated by testing it against the existing system

Integration of cellulases recycling with 2nd generation bioethanol production from waste paper residues

Nowadays, the economic feasibility of 2G-bioethanol depends on two important factors: raw material and the cost of enzymes. Using urban and industrial residues may represent a significant improvement, as it refers to a material with a negative cost and with no soil competition. One of these materials is the recycled paper sludge (RPS), which presents a considerable fraction of carbohydrates, but is currently disposed on landfills. Also, the high cost of cellulases demands immediate improvements on their efficiency, where enzyme recycling comes as a promising strategy to achieve that. Here we study the potential of RPS on 2G-bioethanol coupled with a strategy of cellulase recycling. Firstly, after determining a glucan content of only 16 % on RPS, some studies were conducted to increase this fraction. With the neutralization of the carbonates present on RPS, it was possible to considerably increase glucans content to 30 %. Using this new material and employing a high dosage of celluclast, an 86 % saccharification efficiency was obtained within 48 hours at a temperature of 30ºC. Measurements of enzymatic activity in the different fractions indicated a high degree of total activity conservation during the hydrolysis process. Also, it was observed that 84 % of the initial total activity remained on the liquid fraction after hydrolysis, confirming the high potential for enzyme recycling. Current efforts aim the improvement of hydrolysis kinetics using higher temperatures, close to the optimum conditions for cellulases action. However, considering the negative effects of these conditions, a higher thermostability system is required, which will be pursued in the following studies

Implementation of a cellulase recycling system to the hydrolysis of recycled paper sludge

Although 2G-biofuels have been implemented in some countries for some decades now, its economic viability remains an important drawback, hampering it to compete with fossil fuels. Great attention has been given to the discovery of new lignocellulosic substrates and strategies to reduce the amount of enzyme required for this process, both representing critical factors on the process economics. Recycled paper sludge (RPS) is an cellulosic residue obtained from paper recycling process, being mostly incinerated or disposed in landfills. In spite of being comprised by a considerable carbohydrates content, very few studies have exploited this potential. Similarly, although several works have studied the profiles of enzyme adsorption/desorption on lignocellulosic substrates, strategies of cellulase recycling have poorly been implemented so far. Here, we describe the implementation of a cellulase recycling system for the particular case of RPS hydrolysis. Following preliminary results suggesting RPS suitability to be hydrolysed and later fermented, the distribution of enzymes at the end of hydrolysis was initially investigated. For a moderate enzyme loading, 20 FPU/gcellulose, and 5 % solids, 80 % of final Cel7A activity was found in the liquid fraction, and thus can be easily recovered and reutilized in a new round. Solid-bound enzymes, which still correspond to 20 %, were efficiently recovered to an extent around 85 % applying a simple alkaline wash, enabling its equal reutilization for a new hydrolysis. Following these results, 4 consecutive rounds of hydrolysis were conducted with this substrate recovering both cellulase fractions at the end of each round. Additionally, a portion of fresh enzyme, corresponding to 20 % of the original load, was added at each round to compensate activity loss. Ethanol was produced in all rounds although with a decrease over the process, possibly reflecting a reduction on substrate saccharification. Nonetheless, this system enabled a reduction of 60 % on process enzyme corresponding to a significant improvement in the process economics. These results also demonstrate that RPS, a residue that has been widely ignored so far, can be hydrolysed, fermented and is suitable for cellulase recycling, and thus have huge potential to be employed in a bio-refinery context

Valorizing recycled paper sludge by a bioethanol production process with cellulase recycling

The feasibility of cellulase recycling in the scope of bioethanol production from recycled paper sludge (RPS), an inexpensive byproduct with around 39% of carbohydrates, is analyzed. RPS was easily converted and fermented by enzymes and cells, respectively. Final enzyme partition between solid and liquid phases was investigated, the solid-bound enzymes being efficiently recovered by alkaline washing. RPS hydrolysis and fermentation was conducted over four rounds, recycling the cellulases present in both fractions. A great overall enzyme stability was observed: 71, 64 and 100% of the initial Cel7A, Cel7B and -glucosidase activities, respectively, were recovered. Even with only 30% of fresh enzymes added on the subsequent rounds, solid conversions of 92, 83 and 71% were achieved for the round 2, 3 and 4, respectively. This strategy enabled an enzyme saving around 53-60%, while can equally contribute to a 40% reduction in RPS disposal costs.The authors acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462). The financial support of FCT through GlycoCBMs Project PTDC/AGR-FOR/3090/2012–FCOMP-01-0124-FEDER-027948 and the PhD grant to DG (SFRH/BD/88623/2012) is equally acknowledged. The authors also thank RENOVA (Portugal) for kindly providing the recycled paper sludge

The compatibility of earth-based repair mortars with rammed earth substrates

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, ScotlandEarth constructions are susceptible to degradation due to natural or human causes. The degradation of the exterior surface of earth walls is very common, either due to lack of maintenance or to the use of incompatible materials, and often requires the application of a repair mortar. This work analyses experimentally the performance of earth-based repair mortars applied on rammed earth surfaces. The mortars are based on earth collected from rammed earth buildings in south Portugal or on a commercial earth. Eight repair mortars were formulated, with the unstabilized soils or including also small binder content. Four types of binder were tested: hydrated air-lime, natural hydraulic lime, Portland cement and natural cement. The repair mortars were applied on two types of standard defects purposely made on rammed earth blocks, representing the most currently defects found on exterior rammed earth surfaces: standard superficial defect and standard deep defect. The performance of the mortars, their compatibility with the substrates and the visual effectiveness of the intervention were evaluated. It was concluded that the mortars behaved differently when applied on different rammed earth supports. However, the best performances occurred always for the mortars made from unstabilized soil identical to that of the rammed earth substrate. Indeed, the use of stabilizers systematically worsened the behavior of the repair mortars, regardless of the type of binder used for that purpose

Earth-based repair mortars: experimental analysis with different binders and natural fibers

RESTAPIA 2012 - Int. Conf. on Rammed Earth Conservation, Valencia, 21-23 June 2012This work intends to contribute for a better knowledge of earth-based repair mortars. The studied mortars are made of a commercial earth (consisting mainly of clay), and other components namely: sand; powder hydrated air-lime; natural hydraulic lime; Portland cement; Roman cement and natural fibers. The experimental analysis of the mortars in the fresh state consisted in the determination of the consistence by flow table and bulk density. In the hardened state the tests conducted were: linear and volumetric shrinkage; water absorption capillary coefficient; drying test; dynamic modulus of elasticity by measuring the fundamental resonance frequency; flexural and compressive strengths

Cephalopod identification keys to Histioteuthidae, Cranchiidae and Octopodiformes of the Azores, with an updated check-list

This work is a combination of unpublished cephalopod identification keys compiled by Malcolm R. Clarke for the Azores region (Central North Atlantic) and a review of the Octopoda of the Azores by João Gonçalves (MSc Thesis 1993, originally written in Portuguese), updated with recent literature. A regional list of cephalopod species of the Azores is provided totaling 83 species, with identification keys for: i) Histioteuthidae, including five species; ii) Cranchiidae, including eleven species; and iii) Octopodiformes, including Vampyroteuthis infernalis Chun, 1903 (Order Vampyromorpha), three cirrate and fourteen incirrate octopuses. Separate keys are given for Octopodiformes species. The revisions are discussed and a more detailed description of Octopoda species is included.Oma – Observatório do Mar dos Açores ; MARE – Centro de Ciências do Mar e do Ambiente ; IMAR – Instituto do Mar ; DOP – Departamento de Oceanografia e Pescas ; Universidade dos Açoresinfo:eu-repo/semantics/publishedVersio

Flood hazard mapping by integrating airborne laser scanning data, high resolution images and large scale maps: a case study

The assessment and management of flood risks framework impose the mapping of flood hazard in potential flood risks areas. Floods in urban environments may happen due to rainfall extreme events and be exacerbated by saturated or impervious surfaces. Flood risk is greater in urban areas. (...

Study on the use of MgAl hydrotalcites as solid heterogeneous catalysts for biodiesel production

This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 degrees C and 700 degrees C, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1% Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2% FAME in the 2nd reaction step and 34% FAME in the 3rd reaction step. The biodiesel obtained in the transesterification reaction showed composition and quality parameters within the limits specified by the European Standard EN 14214. 2.5% wt catalyst/oil and a molar ratio methanol:oil of 9:1 or 12:1 at 60 -65 degrees C and 4 h of reaction time are the best operating conditions achieved in this study. This study showed the potential of Mg/Al hydrotalcites as heterogeneous catalysts for biodiesel production. (C) 2011 Elsevier Ltd. All rights reserved