Separation with the aid of surface and interfacial tensions

The investigations described in this thesis were aimed at developing or laying the foundation of novel techniques of liquid/solid and liquid/liquid separation by utilising the capillary effect. In Part I the studies related to the extraction of water from an agglomerate of particulate solids and water (i. e. dewatering) by means of ceramic elements are described. These studies clearly showed that although water can be extracted from the agglomerate by ceramic elements and evaporated to atmosphere, the rate of extraction is generally too low for commercial application of the technique. Part II of this thesis deals with the separation of two immiscible liquids (i. e. water and oil) using a ceramic filter tube either as a 'threshold pressure' separator or a coalescer. It was found that diesel fuel, for instance, could be separated to practically 100% efficiency from a secondary dispersion of oil/water, provided the applied pressure across the tube is maintained below a critical value. This technique could form the basis of a very efficient commercial oil/water separator

Thermo-oxidative characterisation of the residues from persimmon harvest for its use in energy recovery processes

[EN] The residues from the harvest of persimmon fruit will be thermally valorised by means of high temperature reactions within a spouted bed reactor. With the aim to obtain valuable information for the design of the device, the thermo-chemical processes were simulated by multi-rate linear non-isothermal Thermogravimetric Analysis (TGA) using O-2 as carrier gas. In addition, a set of analyses were carried out using Ar as carrier gas in order to evaluate the influence of the atmosphere (oxidative or inert conditions) on the decomposition of the samples evaluating the reactions of pyrolysis. The release of gases was monitored by Evolved Gas Analysis (EGA) with in-line Fourier Transformed Infrared (FT-IR) analysis. The thermochemical reaction was mathematically described through the definition of the main kinetic parameters: activation energy (Ea), pre-exponential factor (In A) and model and order of reaction (n). The so-called kinetic triplet was calculated through the application of a methodology based on complementary isoconversional methods. These results will be the initial parameters that will help design the Spouted Bed Reactor and it is envisaged that they will be used in computer simulation software to achieve a better understanding of the process to obtain the optimum operational parameters. (C) 2016 Published by Elsevier B.V.Moliner, C.; Aguilar, A.; Bosio, B.; Arato, E.; Ribes-Greus, A. (2016). Thermo-oxidative characterisation of the residues from persimmon harvest for its use in energy recovery processes. Fuel Processing Technology. 152:421-429. https://doi.org/10.1016/j.fuproc.2016.07.008S42142915

Performance of Computer Systems; Proceedings of the 4th International Symposium on Modelling and Performance Evaluation of Computer Systems, Vienna, Austria, February 6-8, 1979

These proceedings are a collection of contributions to computer system performance, selected by the usual refereeing process from papers submitted to the symposium, as well as a few invited papers representing significant novel contributions made during the last year. They represent the thrust and vitality of the subject as well as its capacity to identify important basic problems and major application areas. The main methodological problems appear in the underlying queueing theoretic aspects, in the deterministic analysis of waiting time phenomena, in workload characterization and representation, in the algorithmic aspects of model processing, and in the analysis of measurement data. Major areas for applications are computer architectures, data bases, computer networks, and capacity planning. The international importance of the area of computer system performance was well reflected at the symposium by participants from 19 countries. The mixture of participants was also evident in the institutions which they represented: 35% from universities, 25% from governmental research organizations, but also 30% from industry and 10% from non-research government bodies. This proves that the area is reaching a stage of maturity where it can contribute directly to progress in practical problems

Effects and Mechanisms Activated by Treatment with Cationic, Anionic and Zwitterionic Liposomes on an In Vitro Model of Porcine Pre-Pubertal Sertoli Cells

: Liposomes have been successfully used as drug-delivery vehicles, but there are no clinical studies on improved fertility and the few reported experimental studies have been performed in animal models far from humans. The aim of this paper was to study the effects of treatment with cationic, anionic and zwitterionic liposomes on our superior mammalian model of porcine prepubertal Sertoli cells (SCs) to find a carrier of in vitro test drugs for SCs. Porcine pre-pubertal SCs cultures were incubated with different liposomes. Viability, apoptosis/necrosis status (Annexin-V/Propidium iodide assay), immunolocalisation of β-actin, vimentin, the phosphorylated form of AMP-activated protein Kinase (AMPK)α and cell ultrastructure (Transmission Electron Microscopy, TEM) were analysed. Zwitterionic liposomes did not determine changes in the cell cytoplasm. The incubation with anionic and cationic liposomes modified the distribution of actin and vimentin filaments and increased the levels of the phosphorylated form of AMPKα. The Annexin/Propidium Iodide assay suggested an increase in apoptosis. TEM analysis highlighted a cytoplasmic vacuolisation. In conclusion, these preliminary data indicated that zwitterionic liposomes were the best carrier to use in an in vitro study of SCs to understand the effects of molecules or drugs that could have a clinical application in the treatment of certain forms of male infertility

Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240°C and 137 kJ/mol of activation energy in inert conditions and 236°C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels

Mechanical and thermal performance of PLA and PHBV based biopolymers as potential alternatives to PET

[EN] The evaluation of the mechanical and thermal properties of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polylactide (PLA) and their biocomposites (containing 30%wt of sisal in their composition) has been studied and compared to poly(ethylene terephthalate) (PET). The addition of sisal to the biopolymeric matrix increased the elastic stiffness of the bio-composites achieving a performance which is comparable to PET. All biocomposites presented lower traction resistance and elongation values respect to PET.The addition of natural fibers improved the thermal stability of PHBV-based samples. The trigger of decomposition happened at lower temperatures respect to PET, but always far above their melting point ensuring a good performance of the composites at high processing temperatures. The apparent activation energies for the biocomposites in inert conditions respect to those for PET indicates a more suitable scenario from the energetic valorisation point of view.Moliner, C.; Badia, J.; Bosio, B.; Arato, E.; Lagazzo, A.; Capurro, M.; Ribes-Greus, A. (2017). Mechanical and thermal performance of PLA and PHBV based biopolymers as potential alternatives to PET. Chemical Engineering Transactions. 57:1417-1422. https://doi.org/10.3303/CET1757237S141714225

Thermal and thermo-oxidative characterisation of rice straw for its use in energy valorisation processes

[EN] The processes of pyrolysis and combustion of rice straw will be carried out in a spouted bed reactor. Both thermo-chemical processes were simulated in the first stage by multi-rate linear non-isothermal thermogravimetric (TGA) experiments using Ar and O-2 as carrier gas respectively. The results obtained from the TGA measurements, the kinetic methodology based on the combination of the iso-conversional methods Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Vyazovkin and the use of Master Plots assessed by Perez-Maqueda criterion have permitted to describe mathematically both thermo-chemical reactions. Lower operational temperatures and higher kinetic parameters (Ea, n, A) were required to carry out combustion reactions respect to those for pyrolysis. These results will be the initial parameters that will define both thermo-chemical processes in a spouted bed reactor. (C) 2016 Elsevier Ltd. All rights reserved.Moliner, C.; Bosio, B.; Arato, E.; Ribes-Greus, A. (2016). Thermal and thermo-oxidative characterisation of rice straw for its use in energy valorisation processes. Fuel. 180:71-79. https://doi.org/10.1016/j.fuel.2016.04.021S717918

Nonferrous waste foundry sand and milling fly ash as alternative low mechanical strength materials for construction industry: effect on mortars at early ages

An alternative solution to reduce environmental pollution using aluminum waste foundry sand (AWFS) and fly ash (FA) to produce sustainable construction materials was studied. New mortars were prepared by partially replacing ordinary Portland cement with fly ash at 5, 10 and 15 % mass. and a total replace of Ottawa sand (OS) with AWFS. The specimens were cured at 25°C with a 100% relative humidity. The mechanical behavior was evaluated by compression test at the ages of 7, 14 and 28 days. The microstructural characteristics were analyzed by scanning electron microscopy (SEM). The results indicate that the addition of milling fly ash in AWFS mortars increases the mechanical resistance, mostly at 5% mass reaching the maximum value of 10 MPa at 28 days of age. Microstructurally, it was found a porous cement matrix with some cracking caused by the reaction of portland cement with the metallic aluminum remaining in the waste sand, which is correlated to the low mechanical resistance obtained. The final mechanical characteristic makes this new product a serious candidate to be used as a sustainable building material working at low load

Assessing ecotoxicity of an innovative bio-based mulch film: a multi-environmental and multi-bioassay approach

Among the highly diverse range of biobased polymers, polylactic acid (PLA) received vast attention in recent years due to its versatility for different applications and being the first commercially used polymer produced from renewable sources. Production and application of bio-based, biodegradable plastics will have one of the most crucial roles in tackling worldwide plastic pollution. Methods: This study is based on integrative ecotoxicological assessment of an innovative PLA-based agricultural mulch film (BPE-AMF-PLA), developed under the H2020 EU project “BIO-PLASTICS EUROPE”, towards organisms from different environmental compartments (soil, fresh water and marine) and from different trophic levels. Such comprehensive evaluation has an overarching goal to promote environmentally safe and sustainable use of these PLA-based plastics for agricultural and other potential applications. Results: Low-to-no phytotoxicity was obtained in both single-species standardized bioassays, and in a multi-species microcosms experiment. Earthworm reproduction was negatively affected at the lowest test concentration of 0.1% w/w of PLA-based plastic particles. For freshwater Daphnia, reproduction was found a sensitive endpoint, upon exposure to the leachates of the PLA-based plastic. However, the reported toxicity seemed to be caused by the presence of 2-methylnaphthalene, which can be avoided in the production process. As for the marine organisms, algae growth was inhibited with a LOEC = 25 g L−1, whereas test with brine shrimp only revealed stimulation of lipase upon digestion of micro-sized PLA-based plastics. Marine lugworm ingested pristine and UV pre-treated micro-sized plastics, yet without impact either on biological activity, or on the health of the test individuals. Discussion: The approach used in the present work will contribute to product development, environmental safety and sustainable applications of the PLA-based mulch film BPE-AMF-PLA, in the scope of project BIO-PLASTICS EUROPE. Furthermore, the tools and results obtained in this work are a relevant contribution in the framework development for additional support in the certification of the bio-based polymers, being aligned with European zero waste and non-toxicity strategies, certification, and regulations