Life Cycle Assessment of a novel digestate treatment unit for anaerobic digestate plant: a UK case

Management of digestate co-product produced from anaerobic digestion (AD) has become a challenge due to impacts on the environment. Valorising AD into high-value products is not only considered as a solution to this issue but can also make AD more cost-effective. Project NOMAD (Novel Organic recovery using Mobile ADvanced technology) funded by H2020 is currently developing an innovative solution for valorising digestate. A designed mobile unit combines several digestate treatment technologies, i.e., solid-liquid separation, ultraviolet light and ozone oxidation, and electrodialysis. The valuable nutrients are concentrated from the liquid fraction, and the solid fraction is collected as compost. This study adopts Life Cycle Assessment (LCA) methodology to assess environmental impacts of the NOMAD unit incorporated into a UK AD plant, focusing on business-as-usual (BAU) case, NOMAD scenario, and upscaled NOMAD scenario. The BAU case is current management of digestate, where digestate is transported, stored, and applied to farmlands. The NOMAD scenario introduces one unit, capable of addressing digestate 5 ton/day, while the upscaled NOMAD scenario can process all digestate produced from the AD plant. 12 impact categories are selected using ReCiPe 2016. The results show that the upscaled NOMAD scenario can reduce 11%-69% of targeted impacts compared to BAU scenario, with 1%-24% reduction for NOMAD scenario. The NOMAD unit process, either upscaled or one-unit, contributes less than 6% of overall impacts, while AD activities and field application are the main impact contributors. The outcome of these scenarios validates the NOMAD unit for valorisation of digestate from environmental impact perspective

On the Onset of Inflation in Loop Quantum Cosmology

Using a Liouville measure, similar to the one proposed recently by Gibbons and Turok, we investigate the probability that single-field inflation with a polynomial potential can last long enough to solve the shortcomings of the standard hot big bang model, within the semiclassical regime of loop quantum cosmology. We conclude that, for such a class of inflationary models and for natural values of the loop quantum cosmology parameters, a successful inflationary scenario is highly improbable.Comment: 16 pages, 6 figures Amended version to appear in Phys. Rev.

Polymorphic form II of 4,4′-methyl­enebis(benzene­sulfonamide)

In the title compound, C13H14N2O4S2 (alternative names: diphenyl­methane-4,4′-disulfonamide, nirexon, CRN: 535–66-0), the two benzene rings form a dihedral angle of 70.8 (1)°. There are two sets of shorter (H⋯O < 2.1 Å) and longer (H⋯O > 2.4 Å) N—H⋯O hydrogen bonds per sulfonamide NH2 group, which together result in hydrogen-bonded sheets parallel (102). Adjacent sheets are connected to one another by an additional N—H⋯N inter­action so that a three-dimensional network of hydrogen-bonded mol­ecules is formed. The investigated polymorph is identical with the form II previously described by Kuhnert-Brandstätter & Moser [(1981). Mikrochim. Acta, 75, 421–440]

Phenomenology of loop quantum cosmology

After introducing the basic ingredients of Loop Quantum Cosmology, I will briefly discuss some of its phenomenological aspects. Those can give some useful insight about the full Loop Quantum Gravity theory and provide an answer to some long-standing questions in early universe cosmology.Comment: 16 pages, 3 figures; Invited talk in the First Mediterranean Conference on Classical and Quantum Gravity (Crete, Greece

The utilisation and management of the semi-natural woodlands of Lochtayside, 1650-1850

There has been in Scotland, in recent years, a resurgence in interest the past history of our woodland, and their future management. The work of Lindsay in the 1970's did much to scotch earlier misconceptions about the utilisation and management of Highland woodlands (Lindsay 1974). Rather than being wholly exploitative, commercial influences during the 18th and 19th centuries may, in fact, have helped temper further woodland decline. It is now generally recognised that non-commercial influences may have been more significant in the evolution of woodlands in the historic period. It is now generally recognised that an understanding of past influences can contribute to future management strategies. This thesis therefore set out to examine the utilisation and management of the semi-natural woodlands of Lochtayside, and in particular, the commercial and non-commercial uses of the woodlands, and their subsequent management. It is hoped that results of this study would both suppliment our existing understanding of Scottish woodland history, and be taken into consideration in the debate on future management strategies. Initially, the study provides a context for the processes of woodland utilistion and management. Thus, the principal decisionmakers involved in the determination of woodland policies on Lochtayside were examined: the Campbells of Glenorchy. Both internal and external factors which might affect their decisions were also investigated. A critical evaluation of the sources for a woodland history study followed. Sources included, contemporary published works relating to the Highland rural society and the economy; the primary documentary source, i.e., the Breadalbane muniments; and cartographic sources, primarily, the Pont Map, the Roy Map, both the Fair and the Protracted versions, the 1769 Survey of Lochtayside and the 1st edition Ordnance Survey. A critical assessment of the advantages and disadvantages is regarded as fundamental to woodland history, and the study explored the limitations of using such sources, in particular the cartographic evidence. Finally, the non-commercial use of the produce and area of the semi-natural woodlands on Lochtayside, and the commercial use of these woodlands, including for bark, timber and charcoal was examined. Conclusions reached suggest there was a complex relationship between these two forms of use which affected the management of the woodlands, and ultimately the extent and composition of the woodlands on Lochtayside. It became clear that the relationship between the agriculture and woodlands was critical. The precise nature of this relationship, however, requires further examination

Scattering of cosmic strings by black holes: loop formation

We study the deformation of a long cosmic string by a nearby rotating black hole. We examine whether the deformation of a cosmic string, induced by the gravitational field of a Kerr black hole, may lead to the formation of a loop of cosmic string. The segment of the string which enters the ergosphere of a rotating black hole gets deformed and, if it is sufficiently twisted, it can self-intersect chopping off a loop of cosmic string. We find that the formation of a loop, via this mechanism, is a rare event. It will only arise in a small region of the collision phase space, which depends on the string velocity, the impact parameter and the black hole angular momentum. We conclude that generically, the cosmic string is simply scattered or captured by the rotating black hole.Comment: 11 pages, 2 figures, RevTe

Density perturbations in Kaluza--Klein theories during a de Sitter phase

In the context of Kaluza-Klein theories, we consider a model in which the universe is filled with a perfect fluid described by a barotropic equation of state. An analysis of density perturbations employing the synchronous gauge shows that there are cases where these perturbations have an exponential growth during a de Sitter phase evolution in the external space.Comment: LaTex file, 10 pages. To be published in Classical and Quantum Gravit