CAPMIX -Deploying Capacitors for Salt Gradient Power Extraction

AbstractThe process of mixing sea and river water can be utilised as a power source. At present, three groups of technology are established for doing so; i) mechanical; Pressure Retarded Osmosis PRO, ii) electrochemical reactions; Reverse ElectroDialysis (RED) and Nano Battery Electrodes (NBE) and iii) ultra capacitors; Capacitive Double Layer Expansion (CDLE) and Capacitors charge by the Donnan Potentials (CDP). The chemical potential for salt gradient power systems is only limited by the feed solution concentrations and is the same for all types of salt power branches, but the electric work to the grid, however, relies on the route of conversion and means chosen therein. The CAPMIX project is a joint project to develop and explore ultra capacitors for doing so.Ultra-capacitor materials can interact with sea and river water in order to be deployed as an electricity source. The author consortium is currently exploring two routes to extract the potential free energy from mixing sea and river water by such means. These two routes are the Capacitive Double Layer Expansion (CDLE) and Capacitors charge by the Donnan Potentials (CDP), which are both recently reported, since 2009. The denominator of the two processes is the porous carbon capacitors constituting the capacitors where the chemical energy is converted into electric energy (current). The CDP differs from the CDLE mainly because it includes the use of membranes in addition to the capacitor materials

Valorization of lubricant-based wastewater for bacterial neutral lipids production: growth-linked biosynthesis

Available online 24 May 2016Lipids produced by microorganisms are currently of great interest as raw material for either biofuels or oleochemicals production. Significant biosynthesis of neutral lipids, such as triacylglycerol (TAG) and wax esters (WE) are thought to be limited to a few strains. Hydrocarbonoclastic bacteria (HCB), key players in bioremediation of hydrocarbon contaminated ecosystems, are among this group of strains. Hydrocarbon rich wastewaters have been overlooked concerning their potential as raw material for microbial lipids production. In this study, lubricant-based wastewater was fed, as sole carbon source, to two HCB representative wild strains: Alcanivorax borkumensis SK2, and Rhodococcus opacus PD630. Neutral lipid production was observed with both strains cultivated under uncontrolled conditions of pH and dissolved oxygen. A. borkumensis SK2 was further investigated in a pH- and OD-controlled fermenter. Different phases were assessed separately in terms of lipids production and alkanes removal. The maximum TAG production rate occurred during stationary phase (4 mg-TAG/L h). The maximum production rate of WE-like compounds was 15 mg/L h, and was observed during exponential growth phase. Hydrocarbons removal was 97% of the gas chromatography (GC) resolved straight-chain alkanes. The maximum removal rate was observed during exponential growth phase (6 mg-alkanes/L h). This investigation proposes a novel approach for the management of lubricant waste oil, aiming at its conversion into valuable lipids. The feasibility of the concept is demonstrated under low salt (0.3%) and saline (3.3%) conditions, and presents clues for its technological development, since growth associated oil production opens the possibility for establishing continuous fermentation processes.The authors thank the FCT Strategic Project of UID/BIO/04469/ 2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124- FEDER-027462) and the Project “BioEnv - Biotechnology and Bioengineering for a sustainable world”, REF. NORTE-07-0124- FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 e O Novo Norte), QREN, FEDER

Materials selection for optimum energy production by double layer expansion methods

NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Power Sources. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Power Sources (2014) DOI:http://dx.doi.org/10.1016/j.jpowsour.2013.12.125The capacitive mixing procedure for energy extraction based on Double Layer Expansion (CDLE) belongs to the group of so-called CAPMIX techniques, which aim at obtaining energy from the salinity difference between fresh and sea waters. Specifically, the CDLE technique takes advantage of the voltage rise that occurs when sea water is exchanged for river water in a pair of porous electrodes which jointly behave as an electrical double layer supercapacitor. In this article, we deal with some experimental aspects that are key for optimizing the extracted energy, and have not been analyzed yet with sufficient detail. This investigation will help in evaluating those parameters which we need to be fixed in a future CDLE device. These include the charging potential, the durations of the different cycle steps, the load resistance used, and the porosity and hydrophilicity of the carbon.Departamento de Física Aplicada, Universidad de GranadaThe research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial support from Junta de Andalucía (Spain), project PE-2008-FQM3993 is also gratefully acknowledged

Ecology and application of haloalkaliphilic anaerobic microbial communities

Haloalkaliphilic microorganisms that grow optimally at high-pH and high-salinity conditions can be found in natural environments such as soda lakes. These globally spread lakes harbour interesting anaerobic microorganisms that have the potential of being applied in existing technologies or create new opportunities. In this review, we discuss the potential application of haloalkaliphilic anaerobic microbial communities in the fermentation of lignocellulosic feedstocks material subjected to an alkaline pre-treatment, methane production and sulfur removal technology. Also, the general advantages of operation at haloalkaline conditions, such as low volatile fatty acid and sulfide toxicity, are addressed. Finally, an outlook into the main challenges like ammonia toxicity and lack of aggregation is provided.This work was performed in the TTIW- cooperation framework of Wetsus, European Centre of Excel- lence for Sustainable Water Technology (www.wetsus.nl). Wetsus is funded by the Dutch Ministry of Economic Affairs, the European Union Regional Development Fund, the Province of Fryslân, the City of Leeuwarden and the EZ/Kompas program of the“ Samenwerkingsverband Noord-Nederland”. The authors would like to thank the participants of the research theme "Sulfur", namely Paqell, for fruitful discussions and financial suppor

Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly

The final edited version of the paper can be found at: http://pubs.acs.org/articlesonrequest/AOR-c9UMxSzGY3eiU5SENNgT The complete citation is: Ahualli, S.; et al. Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly. Journal of Physical Chemistry, 118(29): 15590-15599 (2014). DOI:10.1021/jp504461mOpen access in the Journal on May 26, 2015In this work we consider the extent to which the presence of multi-valent ions in solution modifies the equilibrium and dynamics of the energy production in a capacitive cell built with ion-exchange membranes in contact with high surface area electrodes. The cell potential in open circuit (OCV) is controlled by the difference between both membrane potentials, simulated as constant volume charge regions. A theoretical model is elaborated for steady state OCV, first in the case of monovalent solutions, as a reference. This is compared to the results in multi-ionic systems, containing divalent cations in concentrations similar to those in real sea water. It is found that the OCV is reduced by about 25 % (as compared to the results in pure NaCl solutions) due to the presence of the divalent ions, even in low concentrations. Interestingly, this can be related to the “uphill” transport of such ions against their concentration gradients. On the contrary, their effect on the dynamics of the cell potential is negligible in the case of highly charged membranes. The comparison between model predictions and experimental results shows a very satisfactory agreement, and gives clues for the practical application of these recently introduced energy production methods.The research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial support from Junta de Andalucia, Spain (PE2012-FQM 694) is also acknowledged. One of us, M.M.F., received financial support throughan FPU grant from the Universityof Granada

Temperature effects on energy production by salinity exchange

This is an unedited version of this paper. The publisher version can be reached in this URL: http://pubs.acs.org/doi/abs/10.1021/es500634fIn recent years, the capacitance of the interface between charged electrodes and ionic solutions (the electric double layer) has been investigated as a source of clean energy. Charge is placed on the electrodes either by means of ion-exchange membranes or of an external power source. In the latter method, net energy is produced by simple solution exchange in open circuit, due to the associated decrease in the capacitance of the electric double layer. In this work, we consider the change in capacitance associated with temperature variations: the former decreases when temperature is raised, and, hence, a cycle is possible in which some charge is put on the electrode at a certain potential and returned at a higher one. We demonstrate experimentally that it is thus viable to obtain energy from electric double layers if these are successively contacted with water at different temperatures. In addition, we show theoretically and experimentally that temperature and salinity variations can be conveniently combined to maximize the electrode potential increase. The resulting available energy is also estimated.Departamento de Física AplicadaThe research leading to these results received funding from the European Union 7th Frame-work Programme (FP7/2007-2013) under agreement No. 256868. Further Financial supports from Junta de Andalucía, project FQM 694, and Ministerio de Economía y Competitividad (Spain), project FIS2013-47666-C3-1-R

Inadvertently Making Cybercriminals Rich: A Comprehensive Study of Cryptojacking Campaigns at Internet Scale

Cryptojacking, a phenomenon also known as drive-by cryptomining, involves stealing computing power from others to be used in illicit cryptomining. While first observed as host-based infections with low activity, the release of an efficient browser-based cryptomining application -- as introduced by Coinhive in 2017 -- has skyrocketed cryptojacking activity in recent years. This novel method of monetizing Web activity attracted both website owners and cybercriminals seeking new methods to profit from. Website owners installed a cryptominer on their domains, while cybercriminals deployed cryptominers in large campaigns spread over numerous domains. Several studies developed detection methods to identify these browser-based cryptominers on websites, but none of these studies focused on the extent and coordination of campaigns deployed by adversaries. Furthermore, the prevalence of cryptojacking on websites is not well estimated yet and the potentially largest attack vector -- a man-in-the-middle attack -- has never been researched before.In this thesis, we perform multiple large studies on cryptojacking to fill these gaps. After crawling a random sample of 49M domains, 20% of the Internet, we conclude that cryptojacking is present on 0.011% of all domains and that adult content is the most prevalent category of websites affected. We show that this percentage is significantly larger in the popular part of the Internet. This led to the conclusion that surveying solely domains listed in the Alexa Top 1M to estimate cryptojacking prevalence results in an overestimation of the problem. Furthermore, we show that infection rates on different Top Level Domains (TLDs) differ widely, as the Russian zone is home to a disproportionate number of cryptojacking domains, while other large TLDs -- such as .com -- show a significantly lower number of infections.In another crawl, we have identified 204 cryptojacking campaigns on websites, an order of magnitude more than previous work, which indicates that the extent of these campaigns is heavily underestimated. The results of the two crawls combined reveal that 48% of all cryptojacking activity on websites is organized. The identified campaigns ranged in sizes from only 5 to 987 websites and we discovered that cybercriminals have chosen third-party software -- such as WordPress and Drupal -- as their method of choice for spreading cryptojacking infections efficiently. With a novel method of using NetFlow data recorded in a Tier 1 network, we estimated the popularity of mining applications, which showed that while Coinhive has a larger installed base, CoinImp WebSocket proxies were digesting significantly more traffic in the second half of 2018.We have reported about a new attack vector that drastically overshadows all other cryptojacking activity. Through a firmware vulnerability in MikroTik routers, cybercriminals are able to rewrite outgoing user traffic and embed cryptomining code in every outgoing Web connection. Thus, every Web page visited by any user behind an infected router would mine to profit the adversaries. Based on the aforementioned NetFlow data, weekly third-party crawls and network telescope traffic, we were able to follow their activities over a period of 10 months. We report on the modus operandi and coordinating infrastructure of the perpetrators, which were during this period in control of up to 1.4M routers, which is approximately 70% of all MikroTik devices deployed in the world. During the peak of this attack, more than 440K routers were infected concurrently.We have discovered that half of the infected routers are patched within 18 days after compromise, but 30% of the infections last longer than 50 days. Additionally, we observed different levels of sophistication among adversaries, ranging from individual installations to campaigns involving large numbers of routers. The combination of datasets allowed us to link tens of seemingly different infections to one actor.Our analysis of cryptojacking with a focus on organized campaigns has shown that cybercriminals have successfully discovered a new method for monetary gain. With the discontinuation of Coinhive due to decreased Monero prices in March 2019, the cryptojacking landscape has changed enormously, and we are curious who will fill this power vacuum. As browser-based mining is not anywhere near as profitable as it was in early 2018, we believe that singular cryptojacking activity -- by individual website owners -- will decrease. However, we expect adversaries to find possibilities of deploying cryptojacking at an even larger scale to still be profitable. This stresses the importance of researching campaigns, as the reuse of techniques, tactics and procedures in deploying them provides an effective angle to detect and mitigate these malicious activities. With prices decreasing throughout 2018, one would expect that this problem will eventually solve itself. Apart from the discontinuation of Coinhive, there is no clear indication that this is the case, as Monero prices have started to recover in the first months of 2019. If this trend continues, we expect to experience another outbreak of large cryptojacking campaigns, as robust defenses are still not widely implemented.Computer Science | Data Science and Technolog

Sulfate reduction under acidic conditions for selective model recovery

Dit proefschrift heeft als doel om processen te ontwikkelen voor selectieve metaal herwinning uit afvalwater and processtromen die meerdere metalen bevatten, door gebruik te maken van sulfaat reductie onder zure omstandighede