1,264 research outputs found
A Branching Time Model of CSP
I present a branching time model of CSP that is finer than all other models
of CSP proposed thus far. It is obtained by taking a semantic equivalence from
the linear time - branching time spectrum, namely divergence-preserving coupled
similarity, and showing that it is a congruence for the operators of CSP. This
equivalence belongs to the bisimulation family of semantic equivalences, in the
sense that on transition systems without internal actions it coincides with
strong bisimilarity. Nevertheless, enough of the equational laws of CSP remain
to obtain a complete axiomatisation for closed, recursion-free terms.Comment: Dedicated to Bill Roscoe, on the occasion of his 60th birthda
Transport, Industrial and Commercial Refrigeration – A research project
The Climate Change Act commits the UK to reach net zero emissions by 2050, tackling hard to abate areas. A significant energy end use, often overlooked in policy, is refrigeration and there is a gap in our understanding of transport, industrial and commercial refrigeration (TICR) emissions. Essential for multiple applications across the cold chain, this paper assesses the size of TICR emissions, and opportunities for research and innovation. Our initial results suggest that 6% of industrial electricity use is for refrigeration, with large uncertainty in this figure. To address this knowledge gap, we reviewed available data sources to estimate the UK’s carbon emissions and produce a breakdown per application sector. In an industry dominated by SMEs with low-risk appetite and innovations with low readiness levels, we explore ways, which TICR could decarbonise in order to reach the UK’s Net Zero ambitions, through innovation and better data
European White Book on Real-Time Power Hardware in the Loop Testing : DERlab Report No. R- 005.0
The European White Book on Real-Time-Powerhardware-in-the-Loop testing is intended to serve as a reference document on the future of testing of electrical power equipment, with specifi c focus on the emerging hardware-in-the-loop activities and application thereof within testing facilities and procedures. It will provide an outlook of how this powerful tool can be utilised to support the development, testing and validation of specifi cally DER equipment. It aims to report on international experience gained thus far and provides case studies on developments and specifi c technical issues, such as the hardware/software interface. This white book compliments the already existing series of DERlab European white books, covering topics such as grid-inverters and grid-connected storag
Fracionamento físico do solo em estudos de matéria orgânica.
Fracionamento físico: base conceitual; Método densimétrico: fração leve (FL-livre); Fração leve oclusa (FL-oclusa); Fração pesada (FP); Método granulométrico; Fracionamento em COM-secundários; Fracionamento COM-primários.bitstream/item/38820/1/LV20023.pdfDocumento online
Preserving Liveness Guarantees from Synchronous Communication to Asynchronous Unstructured Low-Level Languages
In the implementation of abstract synchronous communication in asynchronous unstructured low-level languages, e.g. using shared variables, the preservation of safety and especially liveness properties is a hitherto open problem due to inherently different abstraction levels. Our approach to overcome this problem is threefold: First, we present our notion of handshake refinement with which we formally prove the correctness of the implementation relation of a handshake protocol. Second, we verify the soundness of our handshake refinement, i.e., all safety and liveness properties are preserved to the lower level. Third, we apply our handshake refinement to show the correctness of all implementations that realize the abstract synchronous communication with the handshake protocol. To this end, we employ an exemplary language with asynchronous shared variable communication. Our approach is scalable and closes the verification gap between different abstraction levels of communication
Heat Recovery Opportunities from Electrical Substation Transformers
The transformation of voltages in electrical substations leads to energy losses in the form of waste heat; the quantity of which depends on transformer size and electrical loading. This paper investigates how a novel waste heat source, namely transformer waste heat could be harvested and distributed via district heating networks. Firstly, the investigation considered nameplate heat loss factors to quantify the theoretical waste heat potential from electrical substation transformers in England, Wales and Northern Ireland, which varied from 3.0 to 5.4 TWh.a-1, equivalent to between 0.7 and 1.25% of annual heat demand for these countries, depending on loading assumptions. A number of heat recovery approaches which could be integrated with existing transformer cooling systems were then proposed. A spreadsheet model was then developed to simulate heat recovery from a transformer, together with the upgrade of the recovered heat using a heat pump prior to delivery via district heating. The model was used to evaluate the merits of capturing transformer waste heat losses, estimated using industry supplied electrical loading data, to meet different heat network demands based on an existing network, compared to conventional heating technologies. Findings suggest that the system proposed can achieve levelised costs that are up to 17% lower than the running costs of air-source heat pumps, whilst reducing emissions by almost 80% when displacing gas boilers. The methodology hereby described can also be used to evaluate the feasibility of recovering transformer waste heat in other countries
Cultivo do feijão e da mandioca conservando o solo.
bitstream/CPAP/56439/1/ADM026.pdfFormato eletrônico
Greenhouse Gasses emissions and land use in Mato Grosso do Sul (MS) State: an exploratory study to the MS carbon neutral initiative.
Climate Change Policy of Mato Grosso do Sul (CCP-MS) was stablished by the State Law 4.555/2014 (Lei 4.555/2014). The state assumed a voluntary reduction in greenhouse gases emissions (GHG) of 20% by 2020 in relation to 2005 emissions. To reach this target, the CCP- MS appointed a number of strategies, including the State Program on Climate Change (PROCLIMA). The program will structure the basis to calculate and monitor the emission inventories of MS, and launch initiatives towards a low carbon emission economy. The current inventories are based on global and national standards and emission factors that are not completely adapted to particular characteristics of MS. Some emission factors are probably overestimating the net GHG emissions. Complementarily, the final balance of GHG do not consider some important mechanisms that absorbs carbon in conservative land use systems, e.g. no-tillage crop farming, improved sown pastures, zero-burning sugarcane plantations and integrated crop-livestock-forestry (ICLF) systems; as well as soil carbon and aboveground biomass through afforestation and ICLF. The objective of MS Carbon Neutral Project is to create the methodological basis for a low carbon economy in Mato Grosso do Sul
Incompleteness of relational simulations in the blocking paradigm
Refinement is the notion of development between formal specifications For specifications given in a relational formalism downward and upward simulations are the standard method to verify that a refinement holds their usefulness based upon their soundness and joint completeness This is known to be true for total relational specifications and has been claimed to hold for partial relational specifications in both the non-blocking and blocking interpretations
In this paper we show that downward and upward simulations in the blocking interpretation where domains are guards are not Jointly complete This contradicts earlier claims in the literature We illustrate this with an example (based on one recently constructed by Reeves and Streader) and then construct a proof to show why Joint completeness fails in general (C) 2010 Elsevier B V All rights reserve
District Heat Networks: Addressing Categorisation to Unlock Deployment Potential
District heating (DH) consists of substantial energy infrastructures in many urban areas around the world, which offer a significant opportunity for achieving economies of scale and increasing the energy efficiency of the built environment. Heat networks have been identified by the UK Government as an essential mechanism for decarbonising heat. However, different to other European countries, the UK heat network market is minimal, meeting only around 3% of overall heat demand. Many of these networks use Combined Heat and Power (CHP) technologies, often driven by carbon-intensive gas engines. If the UK is to achieve its netzero target, these CHP systems need to be modified or replaced with low-carbon alternatives such as heat pumps. One challenge to the growth of low-carbon heat networks in the UK relates to a lack of clarity when categorising them as either communal or district. These systems have different merits and peculiarities that affect their potential as scalable tools for decarbonisation. This paper aims to address this challenge by proposing new definitions that clearly separate district and communal concepts. This is achieved by analysing the status of heat networks in the UK and London, which is complemented by a review of current definitions available in the literature. The potential implications of misclassification to the development of DH in the UK are then discussed, with a focus on how policy needs to establish clear boundaries in order to guide the transition towards a low-carbon DH market in the UK. By addressing the issue of inconsistent categorisation and improving data accuracy, this paper serves as a foundation for future research and development efforts aimed at overcoming the barriers to the broader deployment of low-carbon heat networks in the UK
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