Localization of Negative Energy and the Bekenstein Bound

A simple argument shows that negative energy cannot be isolated far away from positive energy in a conformal field theory and strongly constrains its possible dispersal. This is also required by consistency with the Bekenstein bound written in terms of the positivity of relative entropy. We prove a new form of the Bekenstein bound based on the monotonicity of the relative entropy, involving a "free" entropy enclosed in a region which is highly insensitive to space-time entanglement, and show that it further improves the negative energy localization bound.Comment: 5 pages, 1 figur

Relative Entropy and Holography

Relative entropy between two states in the same Hilbert space is a fundamental statistical measure of the distance between these states. Relative entropy is always positive and increasing with the system size. Interestingly, for two states which are infinitesimally different to each other, vanishing of relative entropy gives a powerful equation $\Delta S=\Delta H$ for the first order variation of the entanglement entropy $\Delta S$ and the expectation value of the \modu Hamiltonian $\Delta H$. We evaluate relative entropy between the vacuum and other states for spherical regions in the AdS/CFT framework. We check that the relevant equations and inequalities hold for a large class of states, giving a strong support to the holographic entropy formula. We elaborate on potential uses of the equation $\Delta S=\Delta H$ for vacuum state tomography and obtain modified versions of the Bekenstein bound.Comment: 75 pages, 3 figures, added reference

Cultivating Camelina for sustainable aviation fuels in EU med marginal land recovered with co-composted biochar and digestate: Preliminary results

The H2020 BIO4A project aims at producing and deploying Sustainable Aviation Fuels (SAF) at large scale in Europe. A major oil refinery, owned and operated by Total based on Axen’s technology, will run in non-segregated full jet-mode, targeting the production of 5 kt of ASTM-certified bio-based HEFA jet fuel. The produced SAF will then be used in commercial passenger flights: the demonstration activities will be complemented by market and policy analysis. While this part of BIO4A represent the industrial component of the project, the issue of developing additional alternative routes for supplying sustainable lipids to the HVO process represents the key R&D part: this addresses the production of Camelina in EU MED marginal land, recovered by biochar or COMBI addition. The production of a novel soil amendment, here named COMBI (COMpost + BIochar), and the evaluation of its performances to increase soil resilience in marginal lands prone to desertification in Spain, are therefore the main R&D actions. Co-composted biochar and digestate obtained from biomass anaerobic digestion has been produced and characterized. The use of Biochar and COMBI in marginal land mostly aims at increasing organic matter to the soil, favouring nutrient recycling and availability, increasing soil water holding capacity, and sequestering fixed carbon, thus contributing to the Paris Climate agreement (Climate Change mitigation) and the UN Sustainable Development Goals. In particular, the carbon removed from the atmosphere, differently from most of the CCS routes, where C is stored, is employed to support the adaptation of difficult agricultural lands and regions to climate change, improving soil and agriculture resilience (Climate Change adaptation). Biochar was produced from chestnut woodchips, thermo-chemically converted through the 50 kg/h oxidative slow pyrolysis unit developed at RE-CORD lab, while digestate was obtained from a mesophilic anaerobic digestion plant mostly fed with animal manure. Co-composting was carried out in two different periods: the first one, during the Summer season in Tuscany (IT) in a greenhouse using static windrows, equipped with temperature and moisture sensors, and turned manually twice per week; the second campaign was conducted in the same location, but during the winter season. The characteristics of different types of co-composted biochar-digestate-straw blends (COMBI) were assessed. Main physical and chemical properties were analyzed with respect to the European Biochar Certificate (EBC) standard and the European Compost Network specifications, that developed the European Quality Assurance Scheme (ECN-QAS), for the solid fraction of digestate. The potential dynamic respiration index (PDRI) test was carried out to investigate the biological stability of the solid digestate. The Brunauer–Emmett–Teller (BET) analysis was also performed on the biochar component, so to characterize the biochar in terms of total porosity and pore diameters distribution using the density functional theory (DFT) method. The test compared the composting process of the digestate only with the co-composting process of the same organic matter with the addition of increasing rates of biochar, up to 15% w/w d.b. Results were compared in terms of duration of the bio-oxidative phase and the maximum temperature reached. Products obtained were characterized and compared as regards yield (in terms of organic matter), Humic and Fulvic Acid content, Nitrate and Ammonium-N content. The products were then applied to two sites in Spain, before seeding Camelina crop: each site comprised 7 different microplots of 10 m2 each, and 4 repetitions. The microplots included soil without fertilization (control), soil with NPK fertilization, soil with three different blends of COMBI, soil with only biochar, soil with composted digestate alone. The test sites were located in two different areas of Spain, one South and the other North of Madrid. The same site will continue to be tested in normal rotation with barley over the following two years. The present works report the results of the on-going test campaign, assessing and discussing the benefits of the soil restructuring. Acknowledgments –This project has received funding from the European Union\u27s Horizon 2020 research and innovation programme under grant agreement No 789562. Authors wish to acknowledge INEA and DG RTD for the support given, as well as project partners Total, SkyNRG, CENER, E

Thermochemical Conversion of Microalgae: Challenges and Opportunities

Abstract Research in Advanced Biofuels steadily developed during recent years. A number of highly innovative technologies have been explored at various scale: among these, lignocellulosic ethanol and CTO (Crude Tall Oil)-biofuel technologies already achieved the early-commercial status, while hydrotreating of vegetable oils (HVO, or HEFA) can be considered today fully commercial. However, despite the level of innovation in each specific technological process under consideration, the feedstock maintains a central role in making a biofuel chain really sustainable. In this context, microalgae grown in salt-water and arid areas offers a considerable opportunity for advanced biofuel production: at the same time, however, they also represent a considerable challenge. Processing microalgae in an economic way into a viable and sustainable liquid biofuel (a low-cost mass-produced product) is not trivial. So far, the main attention has been given to cultivating the microorganism, accumulating lipids, extracting the oil, valorising co-products, and treating the algae oil into biodiesel (through esterification) or HEFA (Hydrotreated Esthers and Fatty Acids), this second one representing a very high quality biofuels, almost a drop-in fuel (suitable either for road transport or for aviation), which production exceed 2 Mt y-1 today. However, extracting the algae oil at low cost and at industrial scale is not yet a full industrial mature process, and the still limited market size of algae-to-biofuels makes difficult the development of industrial-scale systems. Nevertheless, another option can be considered, i.e. processing the whole algae into dedicated thermochemical reactors, thus approaching the downstream processing of algae in a completely different way from separation. The present work examines the possible routes for thermochemical conversion of microalgae, distinguishing between dry-processes (namely pyrolysis and gasification) and wet-processes (near critical water hydrothermal liquefaction and hydrothermal gasification). Typical expected elementary composition of major products is given. Main peculiarities of batch versus continuous processing are also discussed from an engineering point of view. Major engineering advantages and challenges in thermochemically conversion of algae are identified and discussed, in view of the production of a transport biofuel. Finally, future perspectives for each route are given in terms of current and expected technological readiness level

Biochar and organic matter co-composting: a critical review

The H2020 BIO4A project aims at producing and deploying Sustainable Aviation Fuels (SAF) at large scale in Europe. A major oil refinery, owned and operated by Total based on Axen’s technology, will run in non-segregated full jet-mode, targeting the production of 5 kt of ASTM-certified bio-based HEFA jet fuel. The produced SAF will then be used in commercial passenger flights: the demonstration activities will be complemented by market and policy analysis. While this part of BIO4A represent the industrial component of the project, the issue of developing additional alternative routes for supplying sustainable lipids to the HVO process represents the key R&D part: this addresses the production of Camelina in EU MED marginal land, recovered by biochar or COMBI addition. The production of a novel soil amendment, here named COMBI (COMpost + BIochar), and the evaluation of its performances to increase soil resilience in marginal lands prone to desertification in Spain, are therefore the main R&D actions. Co-composted biochar and digestate obtained from biomass anaerobic digestion has been produced and characterized. The use of Biochar and COMBI in marginal land mostly aims at increasing organic matter to the soil, favouring nutrient recycling and availability, increasing soil water holding capacity, and sequestering fixed carbon, thus contributing to the Paris Climate agreement (Climate Change mitigation) and the UN Sustainable Development Goals. In particular, the carbon removed from the atmosphere, differently from most of the CCS routes, where C is stored, is employed to support the adaptation of difficult agricultural lands and regions to climate change, improving soil and agriculture resilience (Climate Change adaptation). Biochar was produced from chestnut woodchips, thermo-chemically converted through the 50 kg/h oxidative slow pyrolysis unit developed at RE-CORD lab, while digestate was obtained from a mesophilic anaerobic digestion plant mostly fed with animal manure. Co-composting was carried out in two different periods: the first one, during the Summer season in Tuscany (IT) in a greenhouse using static windrows, equipped with temperature and moisture sensors, and turned manually twice per week; the second campaign was conducted in the same location, but during the winter season. The characteristics of different types of co-composted biochar-digestate-straw blends (COMBI) were assessed. Main physical and chemical properties were analyzed with respect to the European Biochar Certificate (EBC) standard and the European Compost Network specifications, that developed the European Quality Assurance Scheme (ECN-QAS), for the solid fraction of digestate. The potential dynamic respiration index (PDRI) test was carried out to investigate the biological stability of the solid digestate. The Brunauer–Emmett–Teller (BET) analysis was also performed on the biochar component, so to characterize the biochar in terms of total porosity and pore diameters distribution using the density functional theory (DFT) method. The test compared the composting process of the digestate only with the co-composting process of the same organic matter with the addition of increasing rates of biochar, up to 15% w/w d.b. Results were compared in terms of duration of the bio-oxidative phase and the maximum temperature reached. Products obtained were characterized and compared as regards yield (in terms of organic matter), Humic and Fulvic Acid content, Nitrate and Ammonium-N content. The products were then applied to two sites in Spain, before seeding Camelina crop: each site comprised 7 different microplots of 10 m2 each, and 4 repetitions. The microplots included soil without fertilization (control), soil with NPK fertilization, soil with three different blends of COMBI, soil with only biochar, soil with composted digestate alone. The test sites were located in two different areas of Spain, one South and the other North of Madrid. The same site will continue to be tested in normal rotation with barley over the following two years. The present works report the results of the on-going test campaign, assessing and discussing the benefits of the soil restructuring. Acknowledgments –This project has received funding from the European Union\u27s Horizon 2020 research and innovation programme under grant agreement No 789562. Authors wish to acknowledge INEA and DG RTD for the support given, as well as project partners Total, SkyNRG, CENER, ETA Florence, and EC JR

Local temperatures and local terms in modular Hamiltonians

We show there are analogs to the Unruh temperature that can be defined for any quantum field theory and region of the space. These local temperatures are defined using relative entropy with localized excitations. We show that important restrictions arise from relative entropy inequalities and causal propagation between Cauchy surfaces. These suggest a large amount of universality for local temperatures, especially the ones affecting null directions. For regions with any number of intervals in two spacetime dimensions, the local temperatures might arise from a term in the modular Hamiltonian proportional to the stress tensor. We argue this term might be universal, with a coefficient that is the same for any theory, and check analytically and numerically that this is the case for free massive scalar and Dirac fields. In dimensions d≥3, the local terms in the modular Hamiltonian producing these local temperatures cannot be formed exclusively from the stress tensor. For a free scalar field, we classify the structure of the local terms.Instituto de Física La Plat

Influence of feedstock and operational conditions on bio-chars derived from the pyrolysis of selected biomasses

The proprieties of bio-char, the solid product from biomass pyrolysis, depends on both the feedstock and process conditions during thermochemical conversion[1]. As regards the interaction of the char with soil (i.e. as soil amendment), surface areas, size and shape of pores are among the most important factors to be considered. [1] P. R. Bonelli , G. Nunell , M. E. Fernández , E. L. Buonomo & A. L. Cukierman (2012) The Potential Applications of the Bio-char Derived from the Pyrolysis of an Agro-industrial Waste. Effects of Temperature and Acid-pretreatment, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 34:8, 746-755, DOI: 10.1080/15567031003681937 Please click Additional Files below to see the full abstract