Energy-Positive Disintegration of Waste Activated Sludge—Full Scale Study

This study aimed to evaluate the effects of mechanical disintegration of waste activated sludge (WAS) on full scale anaerobic digestion, considering the possibility of obtaining a positive energy balance. The results showed that an increase in energy density (εL) used in disintegration was accompanied by an increase in the release of organic compounds from sludge (SCOD increased from 211 ± 125 mg O2/L for εL = 0 kJ/L to 6292 ± 2860 mgO2/L for εL = 180 kJ/L). Some of them were volatile fatty acids. The percentage share of WAS subject to disintegration was also documented as a crucial parameter affecting the efficiency of biogas production. An increase in the value of this parameter from 25% to 100%, even at much lower εL used in disintegration (therefore with much smaller amounts of organic compounds released from sludge flocs) resulted in an increase in biogas production. Conducting disintegration of the entire stream of WAS directed to the fermentation tank at εL 30 kJ/L resulted in an increase in biogas production by 14.1%. Such a surplus would allow production of approximately 360 kWh/d net electricity. Mechanical disintegration of thickened WAS therefore may be an economically justifiable strategy for the intensification of anaerobic sludge stabilisation.

Comment on Coleman-DeLuccia instantons

We complete an old argument that causal diamonds in the crunching region of the Lorentzian continuation of a Coleman-Deluccia instanton for transitions out of de Sitter space have finite area, and provide quantum models consistent with the principle of detailed balance, which can mimic the instanton transition probabilities for the cases where this diamond is larger or smaller than the causal patch of de Sitter space. We review arguments that potentials which do not have a positive energy theorem when the lowest de Sitter minimum is shifted to zero, may not correspond to real models of quantum gravity.

Multimedia Character Modeling Design and Modeling of Cartoon Animation Based on Bayesian Sequence Recommendation Algorithm

With the continuous development of the social economy, cartoon animation and other multimedia and streaming media forms are becoming more and more popular and are loved by all kinds of people, such as monkey king and Nezha. However, the multimedia of these cartoon animation needs to conform to mainstream values and transmit positive energy. In view of these needs and shortcomings, this study relies on the Bayesian sequence recommendation algorithm, combs the three-tier architecture diagram of multimedia character modeling, analyzes it, respectively, from the perspectives of hierarchy, behavior, and interactive process, and tries to build corresponding animation design management documents, so as to provide corresponding decision-making basis to produce animation and develop corresponding results, provide corresponding reference mode for cartoon animation multimedia character manufacturing, complete corresponding cartoon animation multimedia characters faster, and improve cartoon animation multimedia works and efficiency. The simulation results show that the Bayesian sequence recommendation algorithm is effective and can support the design and modeling of cartoon animation multimedia characters.

General bounds on holographic complexity

We prove a positive volume theorem for asymptotically AdS spacetimes: the maximal volume slice has nonnegative vacuum-subtracted volume, and the vacuum-subtracted volume vanishes if and only if the spacetime is identically pure AdS. Under the Complexity=Volume proposal, this constitutes a positive holographic complexity theorem. The result features a number of parallels with the positive energy theorem, including the assumption of an energy condition that excludes false vacuum decay (the AdS weak energy condition). Our proof is rigorously established in broad generality in four bulk dimensions, and we provide strong evidence in favor of a generalization to arbitrary dimensions. Our techniques also yield a holographic proof of Lloyd’s bound for a class of bulk spacetimes. We further establish a partial rigidity result for wormholes: wormholes with a given throat size are more complex than AdS-Schwarzschild with the same throat size.

Ambidextrous light transforms for celestial amplitudes

Low multiplicity celestial amplitudes of gluons and gravitons tend to be distributional in the celestial coordinates z,$$ \overline{z} $$ z ¯ . We provide a new systematic remedy to this situation by studying celestial amplitudes in a basis of light transformed boost eigenstates. Motivated by a novel equivalence between light transforms and Witten’s half-Fourier transforms to twistor space, we light transform every positive helicity state in the coordinate z and every negative helicity state in $$ \overline{z} $$ z ¯ . With examples, we show that this “ambidextrous” prescription beautifully recasts two- and three-point celestial amplitudes in terms of standard conformally covariant structures. These are used to extract examples of celestial OPE for light transformed operators. We also study such amplitudes at higher multiplicity by constructing the Grassmannian representation of tree-level gluon celestial amplitudes as well as their light transforms. The formulae for n-point Nk−2MHV amplitudes take the form of Euler-type integrals over regions in Gr(k, n) cut out by positive energy constraints.

Multi-Criteria Decision Making Optimisation Framework for Positive Energy Blocks for Cities

The Positive Energy Block (PEBlock) is a new paradigm towards low-carbon cities. However, there is a paucity of literature about methods and tools to develop PEBlocks in practice. This study proposes a multi-criteria decision making optimisation framework for PEBlocks for cities. It explores PEBlock scenarios based on adaptable criteria and actions applied to a block composed of three school buildings, where only one acts as a positive node of the future energy network. Findings point out the flexibility of PEBlock scenarios; firstly, selecting a list of 21 potential positive energy scenarios among 300 possible combinations concerning the block analysed, secondly, individuating the optimal solution and finally, comparing it with others based on the weight assigned to the criteria. This study contributes to understanding the emerging properties concerning PEBlocks, discussing their features and stressing main peculiarities compared to other models (e.g., positive energy districts). It also emphasises the PEBlock as a feasible and reliable energy infrastructure to support new urban organisations (e.g., self-organised energy communities), drawing future developments and implications. Limitations associated with this study are also stressed in the conclusion.

A Comprehensive PED-Database for Mapping and Comparing Positive Energy Districts Experiences at European Level

Positive Energy Districts (PEDs) are considered as one of the pioneer strategies to guide cities in their energy planning process towards climate neutrality in an attractive, innovative and human-centered way. The concept of PED is the result of a long co-creation process and integrates several multidimensional features, aiming to promote the sustainable development of urban areas and the transition of cities towards a climate neutral energy system. The paper provides an overview of the first outcomes of WG1 “PED Mapping, Characterization and Learning”, in the research COST Action CA19126 “Positive Energy Districts European Network” (PED-EU-NET). This study describes activities that focus on creating a comprehensive PED-Database by mapping existing concepts, strategies, projects, technological and non-technological solutions related to PEDs in Europe. The main objective of the Database is to support municipalities through the decision-making process by providing strategies for building and running a successful PED that can provide alternatives to consider, and is powered by an interactive web-based map. The design of the Database framework is supported by a step-by-step methodology adopted in the framework of the CA19126 in order to develop the PED-Database as an interactive, updatable and user-friendly tool.