142 research outputs found
Keep circularity meaningful, inclusive and practical: A view into the plastic value chain
Full text linkNew policies to promote the circular economy have created an urgent need for businesses and public authorities to quantify and monitor the level of circularity of materials, components and products. However, flows of materials, components and products through society are inherently complex, involving intricate value chains, many stakeholders, and interests. We argue that current actions may be overly focused on superficial effects, and losing sight of true circular economy goals. Using plastic packaging as an example, the present contribution deliberates the questions, “does measuring circularity address its goals?”, “does it cover new technologies and regional specificities?”, and “can its goals be addressed with simple assessment approaches?”. In answering these questions, we argue that there is an impending risk of cementing policy and infrastructures that may not contribute to true sustainability. Furthermore, future technologies and developing regions are hardly included in the current circularity strategies. To further spark a discussion on the challenge of simplicity, we present a scorecard which can help incumbents to approximate the level of sustainable circularity of their products
BOOK REVIEW: CIPRIAN PORUMBESCU NECUNOSCUT (CIPRIAN PORUMBESCU UNKNOWN), PUBLISHING BY ED. LIDANA, SUCEAVA, 3 EDIŢII, 2011-2013 (ISSN: 2284-712X)
Full text linkIn late May and early June of this year, organized by the Bucovina Cultural Center from Suceava, took place the third edition (2013) of the “Ciprian Porumbescu” European Festival of Arts, having among the guests of honour the Porumbescu’s family descendant, Mrs. Nina Cionca, author of a vast, detailed and richly illustrated monograph about Ciprian Porumbescu. Among a series of notable cultural representations made to celebrate 160 years of the birth of Bucovinean composer Ciprian Porumbescu, in June 1st at Stupca (today: Ciprian Porumbescu), at the Ciprian Porumbescu Memorial Museum, also held at the National Musicological Symposium. Within it have been presented the following papers dedicated to the composer\u27s life and activity: Leca Morariu and the Monumental Monograph Worshiped to Ciprian Porumbescu (author: Vasile Vasile – from the University of Piteşti); The Architectural and Tonal Support of the Dramaturgy of the “Crai nou” (New Philanderer) Operetta by Ciprian Porumbescu (author: Gabriela Coca – from the Babeş-Bolyai University of Cluj-Napoca); “Balada” (The Ballad) of Ciprian Porumbescu – a Representative Creation of the Art Music of Bucovina (19th century) (author: Zamfira Dănilă – from the “George Enescu” Academy of Art - Iaşi); The Reception of Ciprian Porumbescu’s Creation in Banat (author: Constantin Tufan Stan – from the Filaret Barbu School of Fine Arts of Lugoj); „Altarul Mănăstirii Putna” (The Altar of Putna Monastery) (author: Sever Paraschiv Dumitrache – from the Bucovina Cultural Center of Suceava); and The Musicological Trilogy “Ciprian Porumbescu Unknown” to an end (autor: Constanţa Cristescu – from the Bucovina Cultural Center - Suceava). These papers are all included, in this presented volume, with other two studies: Ciprian Porumbescu – Friends and his Collaborators of Braşov (author: the regretted musicologist professor Constantin Catrina from the Transylvania University of Braşov) and The Aspects of the Musical Language and of its Architecture in Compositions by Ciprian Porumbescu (author: Ozana Kalmuski-Zarea – from the “Mihail Jora” Philharmonic of Bacău). In a special chapter, entitled Documenta, this volume contains the facsimile of the manuscript of the orchestra score of the vocal-symphonic work The Altar of Putna Monastery by Ciprian Porumbescu
BOOK REVIEW: CIPRIAN PORUMBESCU NECUNOSCUT (CIPRIAN PORUMBESCU UNKNOWN), PUBLISHING BY ED. LIDANA, SUCEAVA, 3 EDIŢII, 2011-2013 (ISSN: 2284-712X)
Full text linkIn late May and early June of this year, organized by the Bucovina Cultural Center from Suceava, took place the third edition (2013) of the “Ciprian Porumbescu” European Festival of Arts, having among the guests of honour the Porumbescu’s family descendant, Mrs. Nina Cionca, author of a vast, detailed and richly illustrated monograph about Ciprian Porumbescu. Among a series of notable cultural representations made to celebrate 160 years of the birth of Bucovinean composer Ciprian Porumbescu, in June 1st at Stupca (today: Ciprian Porumbescu), at the Ciprian Porumbescu Memorial Museum, also held at the National Musicological Symposium. Within it have been presented the following papers dedicated to the composer's life and activity: Leca Morariu and the Monumental Monograph Worshiped to Ciprian Porumbescu (author: Vasile Vasile – from the University of Piteşti); The Architectural and Tonal Support of the Dramaturgy of the “Crai nou” (New Philanderer) Operetta by Ciprian Porumbescu (author: Gabriela Coca – from the Babeş-Bolyai University of Cluj-Napoca); “Balada” (The Ballad) of Ciprian Porumbescu – a Representative Creation of the Art Music of Bucovina (19th century) (author: Zamfira Dănilă – from the “George Enescu” Academy of Art - Iaşi); The Reception of Ciprian Porumbescu’s Creation in Banat (author: Constantin Tufan Stan – from the Filaret Barbu School of Fine Arts of Lugoj); „Altarul Mănăstirii Putna” (The Altar of Putna Monastery) (author: Sever Paraschiv Dumitrache – from the Bucovina Cultural Center of Suceava); and The Musicological Trilogy “Ciprian Porumbescu Unknown” to an end (autor: Constanţa Cristescu – from the Bucovina Cultural Center - Suceava). These papers are all included, in this presented volume, with other two studies: Ciprian Porumbescu – Friends and his Collaborators of Braşov (author: the regretted musicologist professor Constantin Catrina from the Transylvania University of Braşov) and The Aspects of the Musical Language and of its Architecture in Compositions by Ciprian Porumbescu (author: Ozana Kalmuski-Zarea – from the “Mihail Jora” Philharmonic of Bacău). In a special chapter, entitled Documenta, this volume contains the facsimile of the manuscript of the orchestra score of the vocal-symphonic work The Altar of Putna Monastery by Ciprian Porumbescu
Ciprian Pripoae-Șerbănescu, Subconștient, comunicare, sens (Subconscious, communication, meaning), TopForm, Bucharest, 2018, 95 p.
Full text linkThe volume Subconscious, communication, meaning, published in 2018, by TopForm Publishing House, within the Psychology collection, represents a real contribution in the field of intelligence studies. The author Ciprian Pripoae-Șerbănescu successfully summarizes the concerns in the field of psychology, critical thinking and intelligence, with an emphasis on the persuasive role of communication. After all, the paper can be a starting point for future research, especially due to the interdisciplinary perspective
Enabling dynamic interactions in large scale applications and scientific workflows using semantically specialized shared DataSpaces
No full textEmerging scientific and engineering applications use large-scale parallel machines to simulate, with higher accuracy, complex physical phenomena consisting of dynamically interacting processes. The workflows associated with these applications consist of parallel application codes that need to co- ordinate and interact at runtime. The interactions typically involve large volumes of data that must be exchanged and processed by the codes. The heterogeneous nature of the coupled codes, their numerical formulations, and their data decompositions lead to complex and dynamic interaction and data exchange patterns that are only defined at runtime. Moreover, these simulations often run on separate resources and progress at different rates, which adds to their complexity. Efficient and scalable implementation of these coupled application workflows present several challenging programming, orchestration, coordination, and data exchange requirements. Existing programming frameworks, however, are rigid and provide limited support for the dynamic inter- actions manifested by these applications. For example, existing frameworks need to gather global application knowledge, impose tight synchronization between applications, or demand pre-defined and static interaction patterns that must be known prior to execution. These constraints can introduce significant performance penalties and can limit application interaction programming expressiveness. This thesis explores a new communication and coordination model to enable flexible and asynchronous application coupling for coupled applications workflows. It derives from the tuple-space model and provides the abstraction of a virtual distributed shared-space, which is customized for the application data domain. It enables applications to coordinate and exchange data by inserting and retrieving data objects. This model does not impose any synchronization requirements between independent applications. Data stored on the space can be accessed by multiple applications, which can associatively query the space and retrieve data objects. Furthermore, it enables decoupled and dynamic interactions driven by application computations. This thesis presents DataSpaces, a prototype implementation of the distributed shared-space model. DataSpaces enables memory-to-memory application coupling and transparent data redistribution. It can complement existing workflow engines to enable in-memory data transports between distributed applications that run on separate resources as part of end-to-end scientific workflows. The thesis also presents ActiveSpaces, which extends DataSpaces and the shared-space model to enable in-transit data processing. It proposes and demonstrates a shift in the data processing paradigm by moving processing code closer to the data. ActiveSpaces provides programming support for defining data processing routines, and a runtime execution system to deploy and remotely execute these routine on the space. The research concepts and software frameworks have been deployed and evaluated using real application workflows in production runs on high-end computing systems.Ph. D.Includes bibliographical referencesIncludes vitaby Ciprian Doca
Central sorting systems in Municipal Solid Waste management
Full text linkAffaldsteknologier udvikler sig over tid og det samme gør de baggrundssystemer og rammevilkår som affaldssystemer afhænger af. Gennem de sidste, og sandsynligvis også de kommende, årtier vil den politiske udvikling således i væsentlig grad ændre rammerne for optimering af affaldssystemernes indretning.De mest afgørende fremtidige baggrundsbetingelser defineres især af tre politiske områder. For det første af stigende bestræbelser for en bedre styring af samfundets materiale-ressourcer, på vejen med en ’cirkulær økonomi’, herunder forhøjede mål for materialegenvinding. For det andet af en omfattende omlægning af energisystemet til vedvarende energi, motiveret af ønsker om fortsat god fremtidig forsyningssikkerhed såvel som reduceret klimapåvirkning. For det tredje af den affaldspolitiske udvikling selv, herunder forbud mod affaldsdeponering, skatter og afgifter og sidst men ikke mindst af den øgede liberalisering og udvikling af et internationalt marked for affaldshåndtering. Hvad angår materialegenvinding fra kommunalt affald, prioriterer den aktuelle europæiske affaldspolitik kildesortering og separat indsamling. Der er imidlertid væsentlige økonomiske og sociale begrænsninger ved denne tilgang, som kan udgøre et grundlag for innovative løsninger. Inden for rammerne af den sandsynlige udvikling af energisystemet vil den nuværende ensrettede affaldsforbrændingstilgang, som indebærer en ikke-fleksibel, kontinuert energigenvinding, miste sine nuværende klimafordele på længere sigt.Hidtidige metoder og praksis for systemanalyse, især livscyklusvurdering, LCA, repræsenterer og vurderer oftest affaldssektoren i et for forsimplet samspil med sine omgivelser med et minimum af fremtidig interaktion og systemeffekter, i de fleste tilfælde gennem inkonsistente metoder og statisk repræsentation af baggrundssystemerne, og deres utilstrækkelige evne til at afspejle konsekvenserne af beslutninger om implementering af forskellige affaldshåndteringsstrategier er kompromitterende for deres brug i beslutningsstøtte. Der er derfor et behov for videreudvikling af metoder til at modellere effekten af interaktioner med omgivende systemer, herunder en involvering af økonomiske modelleringsmetoder.Dette PhD arbejde har undersøgt den rolle og de implikationer mekanisk forsortering og central sortering kan have som en nøgleteknologi i strategier for optimeret ressource- og energigenvinding og minimering af klimapåvirkningen fraaffaldshåndtering i lyset af fremtidens rammebetingelser. Projektets overordnede mål kan nedbrydes i fem del-mål:1) At gennemgå og udbygge den eksisterende viden om fysisk/mekanisk behandling af kommunalt affald, inklusive forståelsen af det nuværende stade for teknisk udvikling, proces-effektivitet og økonomiske aspekter af sorterings- og separations-systemer 2) Gennem teknisk-økonomisk analyse og materiale- og energiflow modellering at simulere og designe alternative affaldssystemers, som sigter mod øget materialegenvinding og øget fleksibilitet i produktionen af affalds-relateret energi 3) At vurdere egnetheden og konkurrencedygtigheden af affaldssystemer med central sortering og identificere de fordele og ulemper sådanne systemer har i form af økonomi, klimapåvirkning og ressourcegenvinding sammenlignet med systemer med affaldsforbrænding 4) At afklare og kvantificere, hvor meget ændrede rammevilkår betyder for de relative fordele og ulemper ved central sortering, herunder Danmarks og EU's politik og ambitioner for vedvarende energi og reduktion af klimapåvirkning 5) At identificere og vurdere betydningen af synergi og andre indirekte effekter i baggrundssystemerne, der opstår som konsekvens af beslutninger om affaldshåndteringErkendelserne fra dette PhD arbejde peger på, at fysisk/mekanisk processering og sortering af kommunalt affald har nået et teknisk modent niveau og spiller en afgørende rolle i både sortering og forbehandling til genvinding af kildesorterede genanvendelige materialer såvel som af blandet rest-affald.Central sortering er allerede anvendt med succes flere steder verden over som en effektiv måde at genvinde de forskellige materialegrupper i kommunalt affald, herunder genanvendelige materialer, bionedbrydeligt organisk affald til særskilt biologisk behandling samt en mere energitæt ’refuse derived fuel’, RDF. Fra et ressourceperspektiv er en stærk motivation for central sortering denne tekniks potentiale for at supplere eller helt erstatte kildesortering og separat indsamling af genanvendelige materialer i områder, hvor sådan indsamling er vanskelig, så som tæt bymæssig bebyggelse.Gennem PhD studiet er simuleret og vurderet et stort antal alternative systemer til håndtering af kommunalt affald, herunder mange kombinationer af separat indsamling af mono-fraktioner, blandende fraktioner og restaffald og mange forskellige teknikker til videre behandling af disse fraktioner. Alle scenarier blev desuden vurderet og sammenlignet på baggrund af et stort antal forskellige scenarier for baggrundssystemerne, og i alt blev opstillet og sammenlignet mere end tusind forskellige affaldssystem modeller. Formålet med denne store varietet var at skabe et robust sammenligningsgrundlag og at forstå, hvordan sammenligningen afhænger af antagelser om fremtidige rammevilkår, for herigennem at skabe et ’mønster’ af resultater for alternativernes relative fordele og ulemper mht. materialegenvinding, energieffektivitet og klimapåvirkning.Materialegenvinding: Resultaterne peger på et højt genvindingspotentiale generelt og på, at systemer med central sortering har den højeste materialegenvinding for alle materialekategorier på nær papir og pap. Mht. bio-affald peges på vigtigheden af kontaminering/kvalitet af den fraseparerede bio-fraktion for den videre anvendelse af fraktionen.Energieffektivitet: Studiet viser, at øget materialegenvinding fra separat indsamling eller central sortering – i affaldsoplandet for et forbrændingsanlæg – ikke sker på bekostning af ringere energigenvinding. Tværtimod blev det påvist, at der opnås samme eller højere energigenvinding, når der tages højde for markedsmekanismerne fra det liberaliserede marked for affaldshåndtering i EU. På længere sigt vil systemer, der prioriterer højere materialegenvinding, bevare en større klimafordel, idet de er mindre følsomme for den faldende fordel ved energifortrængning, der følger af udviklingen mod vedvarende energi i energisystemet.Carbon footprint: Evalueringen af carbon footprint baseredes på konsekvens-LCA, og sammenligningen mellem reference-systemet med affaldsforbrænding og alternative strategier for produktion af bio-methan fra bio-affaldet og RDF fra restaffaldet i fremtidens vedvarende energisystem gav en række robuste konklusioner. På kort til mellemlangt sigt falder klimafordelene ved energigenvinding fra affaldet som nævnt proportionalt med, at den fortrængte energi i energisystemet gradvis ændres til vedvarende energi. Affaldssystemets evne til at opretholde en netto klimagevinst er således fundet at afhænge af, hvor godt energigenvindingen fra affaldet kan integreres i den fluktuerende vedvarende energiproduktion. Fleksibiliteten af energigenvindingen fra affaldet og dens evne til at erstatte spidslast el og varme (dvs. de teknologier, der anvendes, når vinden ikke blæser) bliver derfor afgørende for klimagevinsten fra affaldshåndteringen. Sådan spidslast vil på kort til mellemlangt sigt sandsynligvis være baseret på fossile brændsler og på længere sigt på biomasse. I et vedvarende energi system vil det således være karakteren og oprindelsen af den marginale biomasse, der afgør hvor stor klimagevinst, der er fra fleksibel affalds-baseret energi-genvinding.Systemer med central sortering med produktion af et lagerstabilt RDF til brug for fjernvarme til spidslast i vintersæsonen, blev fundet klimamæssigt særligt attraktive og blev fundet at opretholde netto klimagevinster og at være bedre end konventionel affaldsforbrænding under alle baggrundsbetingelser.Specielt for Danmark, men også relevant for andre lande med stor animalsk produktion i landbruget, er der store klimafordele og sandsynligvis også økonomiske fordele ved at anvende kildesorteret bio-affald som co-substrat i landbrugs-biogasanlæg baseret på husdyrgødning. Klimagevinsten opstår ved enten 1) at tilvejebringelsen at et co-substrat muliggør mere biogas på husdyrgødning og derved medfører mindre udledning af klimagasser fra konventionel håndtering af husdyrgødning eller 2) at bio-affaldet erstatter andre co-substrater, mest sandsynligt energiafgrøder, og dermed undgår den klimabelastninger, der er forbundet med disse.Implementeringen af øget materialegenvinding i lande med fuld affaldsbehandlingskapacitet, herunder fuld forbrændingskapacitet, som fx Danmark, kan påvirke et stigende internationalt marked for affaldshåndtering og dermed affaldshåndteringen i andre lande. Når affaldsstrømme kanaliseres væk fra investeringstung, eksisterende infrastruktur med lang restlevetid som affaldsforbrændingsanlæg, fx via separat indsamling eller central sortering til øget materialegenvinding, udbydes dennes kapacitet på markedet og affald importeres. Det afføder, at den marginale affaldshåndtering på markedet undgås, og dette er deponi. Sådanne kaskade-effekter er i de fleste tilfælde miljømæssigt fordelagtige. Affaldsimport kan på kort til mellemlangt sigt fungere som en økonomisk favorabel overgang i en gradvis afvikling af affaldsforbrænding, idet importeret affald kan understøtte eksisterende forbrændingsanlæg i deres restlevetid, mens investering i ny kapacitet undlades. Waste treatment technologies develop over time, and so do background conditions on which waste management systems rely. During the last and expectedly also the coming decades, political developments have and will, thus, significantly change the framework conditions for optimizing waste management.The dominating future background conditions have been found to be defined especially by the development within three policy areas. Firstly, by increased efforts to ensure a proper management of material resources, providing stepping stones towards a “circular economy”, including enhanced targets for material recovery and recycling. Secondly, an increased integration of renewable energy in energy systems, motivated by objectives both to ensure energy supply security and to mitigate adverse impacts of global warming. Thirdly, by waste management policies themselves, including regulations like banning landfilling, schemes on taxes, fees and subsidies and last but not least, the liberalization and development of an international market for waste management services.With regard to materials recovery for recycling from municipal solid waste (MSW), current European waste policy prioritizes source separation and separate collection. However, there are noticeable economic and social limitations with this approach, which motivate a search for innovative solutions. Within the likely (and politically targeted) development of background energy production, the current “one size fits all” approach towards waste-to-energy (WtE), through continuous waste incineration, is likely to see its current climate benefits compromised in the long term.Current systems analysis methods and practices and specifically waste LCA models most often represent and evaluate the waste management sector in a much too simplistic interaction with its surroundings, accounting for a minimum of probable future system interactions/effects, many times through inconsistent methods and static representations of background systems. Their insufficiency in taking account of consequences of decisions towards implementation of different waste management strategies can compromise them as decision-supporting tools. As such, there is a need for advances in methodological aspects related to modelling effects/interactions with surrounding systems, including better convergence with economic modelling methods.This PhD work investigated the role and implications of mechanical pre-treatment and central sorting as a key waste management technology for strategies to achieve both resource and energy recovery optimizations and to minimize climate impacts of waste management in the context of future framework conditions. The goal of the work was broken down to five main objectives:1) To review and expand the knowledge base on physical/mechanical treatment of municipal waste streams, including current state in technical development, process efficiency and economic aspects of sorting and separation systems. 2) To design and simulate, through techno-economic analysis and material/energy flow modelling, alternative waste management systems which aim at increased material recovery and flexibility in utilization of waste-derived energy. 3) To evaluate the feasibility of waste management systems based on central sorting and identify the advantages and disadvantages of such systems in terms of economy, climate impacts and resource recovery compared to systems based on direct WtE. 4) To explore and quantify the significance of changing background conditions such as the overall Danish and European policy and ambitions for future renewable energy integration and climate change mitigation and how such changing background conditions influence the feasibility of central sorting compared to alternative systems. 5) To identify and assess the significance of conditional synergies and other indirect effects occurring in background systems as a consequence of waste management decisions.Through the findings of this work, it can be concluded that waste physical/mechanical processing and sorting technology have reached a high level of technical maturity, and play a crucial role both in sorting and preparation for recycling of source-separated recyclable materials, and the processing of mixed/residual MSW streams. The concept of central sorting is already applied successfully in numerous places around the world, as an efficient strategy for “material specific treatment”, meaning to gain access to the various material groups in mixed or residual MSW, such as: (1) recyclable materials, (2) biodegradable organic fractions, for dedicated biological treatment, and (3) high-energy content fractions, for production of waste-derived fuels. From a resource recovery perspective, a strong motivation for residual MSW central sorting is its potential to support, or even be an alternative to, source separation and separate collection for recyclable materials, in areas where such programs are difficult to implement or optimize, such as urban agglomerations.Alternative MSW management systems were simulated and evaluated, comprising numerous combinations of separate collection of mono- and commingled waste fractions as well as mixed residual fractions and comprising a variety of downstream treatment/handling approached to these fractions. All scenarios were, in turn, assessed and compared against a large variety of background system scenarios leading to a total of above a thousand waste management models. The aim was to create a robust platform for evaluating the feasibility of systems including central sorting against other systems, to understand the outcome of comparisons and their dependency on framework conditions and to establish a final ‘pattern’ of comparisons allowing a robust interpretation for decision making with respect to all aspects of feasibility, including aspects of resource recovery, energy efficiency, and climate impacts.Material recovery: The results reveal that very high recycling rates are possible, and that central sorting typically improves recycling rates for all material fractions except paper and cardboard. Further, with regard to the bio-waste fraction, there is an important issue of contamination/quality influencing the subsequent options for applying the bio-fraction.Energy efficiency: It was, further, found that the enhanced material recovery on the short-to-medium term does not happen at the expense of less energy recovery. On the contrary, when revealing the mechanisms of a liberal waste market leading to waste imports, the same or a higher amount of waste-derived energy could be supplied to the background energy system when including increased separate collection or central sorting. In a longer term perspective, systems which prioritized recovery of materials for recycling maintained higher GWP savings and were less vulnerable to the decreasing benefits from replacing energy produced in future background systems.Carbon footprint: The evaluation by carbon footprint (based on consequential LCA methodology), of reference (WtE) and alternative strategies to energy integration of waste derived biomethane and RDF, against different sets of background conditions representing the most probable future development of the Danish energy system, yielded a number of robust conclusions. In short-to-medium term, MSW management would see a decrease in GHG savings, consistent with the diminishing share of fossil fuels in the energy system being displaced by the energy recovered from the waste. The ability to maintain net waste-derived GHG savings from waste energy recovery in a longer term perspective is found to be determined by the ability to integrate waste based energy production in the surrounding energy system. Therefore, the flexibility of waste derived energy supply and its ability to displace peak energy production, based on remaining fossil fuels or increasingly biomass, becomes decisive to the resulting carbon footprint of MSW management. In a fully renewable background energy system, the nature of the marginal source for biomass would determine the magnitude of savings related to flexible waste-derived energy production. Systems based on central sorting, with production of storable RDF for intended utilization in the cold season in district heating networks, were indicated as especially relevant, and consistently attained net GW benefits in all modelled background situations superior to direct WtE. Implementation of strategies for increasing recycling and/or optimization of wastederived energy recovery in countries with self-sufficient waste management systems (such as Denmark) and high degree of WtE, can affect waste management operations in other European countries. Such indirect effects manifest themselves through market mechanisms, and are caused by direct consequences of such strategies on the utilization of existing waste treatment infrastructure, specifically capital-intensive, long-lived WtE infrastructure – i.e. if incineration capacity is released in a given WtE facility due to a separate collection scheme or the establishment of a central sorting facility, such capacity will soon be filled up by waste import. These effects are in most cases environmentally desirable, as a move up the waste hierarchy in a self-sufficient system seems to have the same implication in countries lacking treatment capacity, affecting marginal waste treatment (i.e. leading to reduction of landfilling). Moreover, short-to-medium term waste imports may act as a support mechanism to the gradual change in how waste is managed, from systems relying heavily on continuous WtE to systems prioritizing material recovery and storable waste-derived energy carriers
Asynchronous data transfers on large scale HPC systems with experiments on the CRAY XT3/XT4
No full textA key challenge faced by the emerging large scale scientific and engineering simulations is effectively and efficiently managing the large volumes of heterogeneous data generated. This includes offloading this data from the compute nodes at runtime, and transferring it over to service nodes or remote clusters for online
monitoring, analysis, or archiving. To be effective, these I/O operations should not impose additional synchronization penalties on
the simulation, should have minimal impact on the computational performance, maintain overall Quality of Service, and ensure that no data is lost.
This thesis describes the design, implementation, and operation of DART (Decoupled Asynchronous Remote Transfers). DART is a thin software layer built on RDMA (Remote Direct Memory Access) communication technology, and specifically the Portals RDMA library to allow fast, low-overhead access to data from simulations running on compute elements, and to support high-throughput low latency
asynchronous I/O transfer of this data.
DART is part of the infrastructure for an integrated simulation of fusion plasma in a Tokamak being developed at the Center for Plasma Edge Simulation (CPES), a DoE Office of Fusion Energy Science (OFES) Fusion Simulation Projects (FSP). A performance evaluation on the Cray XT3/XT4 system at Oak Ridge National Laboratory demonstrates that DART can be used to offload expensive I/O operations to dedicated service nodes allowing more efficient utilization of the compute elements.M.S.Includes bibliographical references (p. 41-42)
Central sorting systems in Municipal Solid Waste management
Full text linkAffaldsteknologier udvikler sig over tid og det samme gør de baggrundssystemer og rammevilkår som affaldssystemer afhænger af. Gennem de sidste, og sandsynligvis også de kommende, årtier vil den politiske udvikling således i væsentlig grad ændre rammerne for optimering af affaldssystemernes indretning.De mest afgørende fremtidige baggrundsbetingelser defineres især af tre politiske områder. For det første af stigende bestræbelser for en bedre styring af samfundets materiale-ressourcer, på vejen med en ’cirkulær økonomi’, herunder forhøjede mål for materialegenvinding. For det andet af en omfattende omlægning af energisystemet til vedvarende energi, motiveret af ønsker om fortsat god fremtidig forsyningssikkerhed såvel som reduceret klimapåvirkning. For det tredje af den affaldspolitiske udvikling selv, herunder forbud mod affaldsdeponering, skatter og afgifter og sidst men ikke mindst af den øgede liberalisering og udvikling af et internationalt marked for affaldshåndtering. Hvad angår materialegenvinding fra kommunalt affald, prioriterer den aktuelle europæiske affaldspolitik kildesortering og separat indsamling. Der er imidlertid væsentlige økonomiske og sociale begrænsninger ved denne tilgang, som kan udgøre et grundlag for innovative løsninger. Inden for rammerne af den sandsynlige udvikling af energisystemet vil den nuværende ensrettede affaldsforbrændingstilgang, som indebærer en ikke-fleksibel, kontinuert energigenvinding, miste sine nuværende klimafordele på længere sigt.Hidtidige metoder og praksis for systemanalyse, især livscyklusvurdering, LCA, repræsenterer og vurderer oftest affaldssektoren i et for forsimplet samspil med sine omgivelser med et minimum af fremtidig interaktion og systemeffekter, i de fleste tilfælde gennem inkonsistente metoder og statisk repræsentation af baggrundssystemerne, og deres utilstrækkelige evne til at afspejle konsekvenserne af beslutninger om implementering af forskellige affaldshåndteringsstrategier er kompromitterende for deres brug i beslutningsstøtte. Der er derfor et behov for videreudvikling af metoder til at modellere effekten af interaktioner med omgivende systemer, herunder en involvering af økonomiske modelleringsmetoder.Dette PhD arbejde har undersøgt den rolle og de implikationer mekanisk forsortering og central sortering kan have som en nøgleteknologi i strategier for optimeret ressource- og energigenvinding og minimering af klimapåvirkningen fraaffaldshåndtering i lyset af fremtidens rammebetingelser. Projektets overordnede mål kan nedbrydes i fem del-mål:1) At gennemgå og udbygge den eksisterende viden om fysisk/mekanisk behandling af kommunalt affald, inklusive forståelsen af det nuværende stade for teknisk udvikling, proces-effektivitet og økonomiske aspekter af sorterings- og separations-systemer 2) Gennem teknisk-økonomisk analyse og materiale- og energiflow modellering at simulere og designe alternative affaldssystemers, som sigter mod øget materialegenvinding og øget fleksibilitet i produktionen af affalds-relateret energi 3) At vurdere egnetheden og konkurrencedygtigheden af affaldssystemer med central sortering og identificere de fordele og ulemper sådanne systemer har i form af økonomi, klimapåvirkning og ressourcegenvinding sammenlignet med systemer med affaldsforbrænding 4) At afklare og kvantificere, hvor meget ændrede rammevilkår betyder for de relative fordele og ulemper ved central sortering, herunder Danmarks og EU's politik og ambitioner for vedvarende energi og reduktion af klimapåvirkning 5) At identificere og vurdere betydningen af synergi og andre indirekte effekter i baggrundssystemerne, der opstår som konsekvens af beslutninger om affaldshåndteringErkendelserne fra dette PhD arbejde peger på, at fysisk/mekanisk processering og sortering af kommunalt affald har nået et teknisk modent niveau og spiller en afgørende rolle i både sortering og forbehandling til genvinding af kildesorterede genanvendelige materialer såvel som af blandet rest-affald.Central sortering er allerede anvendt med succes flere steder verden over som en effektiv måde at genvinde de forskellige materialegrupper i kommunalt affald, herunder genanvendelige materialer, bionedbrydeligt organisk affald til særskilt biologisk behandling samt en mere energitæt ’refuse derived fuel’, RDF. Fra et ressourceperspektiv er en stærk motivation for central sortering denne tekniks potentiale for at supplere eller helt erstatte kildesortering og separat indsamling af genanvendelige materialer i områder, hvor sådan indsamling er vanskelig, så som tæt bymæssig bebyggelse.Gennem PhD studiet er simuleret og vurderet et stort antal alternative systemer til håndtering af kommunalt affald, herunder mange kombinationer af separat indsamling af mono-fraktioner, blandende fraktioner og restaffald og mange forskellige teknikker til videre behandling af disse fraktioner. Alle scenarier blev desuden vurderet og sammenlignet på baggrund af et stort antal forskellige scenarier for baggrundssystemerne, og i alt blev opstillet og sammenlignet mere end tusind forskellige affaldssystem modeller. Formålet med denne store varietet var at skabe et robust sammenligningsgrundlag og at forstå, hvordan sammenligningen afhænger af antagelser om fremtidige rammevilkår, for herigennem at skabe et ’mønster’ af resultater for alternativernes relative fordele og ulemper mht. materialegenvinding, energieffektivitet og klimapåvirkning.Materialegenvinding: Resultaterne peger på et højt genvindingspotentiale generelt og på, at systemer med central sortering har den højeste materialegenvinding for alle materialekategorier på nær papir og pap. Mht. bio-affald peges på vigtigheden af kontaminering/kvalitet af den fraseparerede bio-fraktion for den videre anvendelse af fraktionen.Energieffektivitet: Studiet viser, at øget materialegenvinding fra separat indsamling eller central sortering – i affaldsoplandet for et forbrændingsanlæg – ikke sker på bekostning af ringere energigenvinding. Tværtimod blev det påvist, at der opnås samme eller højere energigenvinding, når der tages højde for markedsmekanismerne fra det liberaliserede marked for affaldshåndtering i EU. På længere sigt vil systemer, der prioriterer højere materialegenvinding, bevare en større klimafordel, idet de er mindre følsomme for den faldende fordel ved energifortrængning, der følger af udviklingen mod vedvarende energi i energisystemet.Carbon footprint: Evalueringen af carbon footprint baseredes på konsekvens-LCA, og sammenligningen mellem reference-systemet med affaldsforbrænding og alternative strategier for produktion af bio-methan fra bio-affaldet og RDF fra restaffaldet i fremtidens vedvarende energisystem gav en række robuste konklusioner. På kort til mellemlangt sigt falder klimafordelene ved energigenvinding fra affaldet som nævnt proportionalt med, at den fortrængte energi i energisystemet gradvis ændres til vedvarende energi. Affaldssystemets evne til at opretholde en netto klimagevinst er således fundet at afhænge af, hvor godt energigenvindingen fra affaldet kan integreres i den fluktuerende vedvarende energiproduktion. Fleksibiliteten af energigenvindingen fra affaldet og dens evne til at erstatte spidslast el og varme (dvs. de teknologier, der anvendes, når vinden ikke blæser) bliver derfor afgørende for klimagevinsten fra affaldshåndteringen. Sådan spidslast vil på kort til mellemlangt sigt sandsynligvis være baseret på fossile brændsler og på længere sigt på biomasse. I et vedvarende energi system vil det således være karakteren og oprindelsen af den marginale biomasse, der afgør hvor stor klimagevinst, der er fra fleksibel affalds-baseret energi-genvinding.Systemer med central sortering med produktion af et lagerstabilt RDF til brug for fjernvarme til spidslast i vintersæsonen, blev fundet klimamæssigt særligt attraktive og blev fundet at opretholde netto klimagevinster og at være bedre end konventionel affaldsforbrænding under alle baggrundsbetingelser.Specielt for Danmark, men også relevant for andre lande med stor animalsk produktion i landbruget, er der store klimafordele og sandsynligvis også økonomiske fordele ved at anvende kildesorteret bio-affald som co-substrat i landbrugs-biogasanlæg baseret på husdyrgødning. Klimagevinsten opstår ved enten 1) at tilvejebringelsen at et co-substrat muliggør mere biogas på husdyrgødning og derved medfører mindre udledning af klimagasser fra konventionel håndtering af husdyrgødning eller 2) at bio-affaldet erstatter andre co-substrater, mest sandsynligt energiafgrøder, og dermed undgår den klimabelastninger, der er forbundet med disse.Implementeringen af øget materialegenvinding i lande med fuld affaldsbehandlingskapacitet, herunder fuld forbrændingskapacitet, som fx Danmark, kan påvirke et stigende internationalt marked for affaldshåndtering og dermed affaldshåndteringen i andre lande. Når affaldsstrømme kanaliseres væk fra investeringstung, eksisterende infrastruktur med lang restlevetid som affaldsforbrændingsanlæg, fx via separat indsamling eller central sortering til øget materialegenvinding, udbydes dennes kapacitet på markedet og affald importeres. Det afføder, at den marginale affaldshåndtering på markedet undgås, og dette er deponi. Sådanne kaskade-effekter er i de fleste tilfælde miljømæssigt fordelagtige. Affaldsimport kan på kort til mellemlangt sigt fungere som en økonomisk favorabel overgang i en gradvis afvikling af affaldsforbrænding, idet importeret affald kan understøtte eksisterende forbrændingsanlæg i deres restlevetid, mens investering i ny kapacitet undlades. Waste treatment technologies develop over time, and so do background conditions on which waste management systems rely. During the last and expectedly also the coming decades, political developments have and will, thus, significantly change the framework conditions for optimizing waste management.The dominating future background conditions have been found to be defined especially by the development within three policy areas. Firstly, by increased efforts to ensure a proper management of material resources, providing stepping stones towards a “circular economy”, including enhanced targets for material recovery and recycling. Secondly, an increased integration of renewable energy in energy systems, motivated by objectives both to ensure energy supply security and to mitigate adverse impacts of global warming. Thirdly, by waste management policies themselves, including regulations like banning landfilling, schemes on taxes, fees and subsidies and last but not least, the liberalization and development of an international market for waste management services.With regard to materials recovery for recycling from municipal solid waste (MSW), current European waste policy prioritizes source separation and separate collection. However, there are noticeable economic and social limitations with this approach, which motivate a search for innovative solutions. Within the likely (and politically targeted) development of background energy production, the current “one size fits all” approach towards waste-to-energy (WtE), through continuous waste incineration, is likely to see its current climate benefits compromised in the long term.Current systems analysis methods and practices and specifically waste LCA models most often represent and evaluate the waste management sector in a much too simplistic interaction with its surroundings, accounting for a minimum of probable future system interactions/effects, many times through inconsistent methods and static representations of background systems. Their insufficiency in taking account of consequences of decisions towards implementation of different waste management strategies can compromise them as decision-supporting tools. As such, there is a need for advances in methodological aspects related to modelling effects/interactions with surrounding systems, including better convergence with economic modelling methods.This PhD work investigated the role and implications of mechanical pre-treatment and central sorting as a key waste management technology for strategies to achieve both resource and energy recovery optimizations and to minimize climate impacts of waste management in the context of future framework conditions. The goal of the work was broken down to five main objectives:1) To review and expand the knowledge base on physical/mechanical treatment of municipal waste streams, including current state in technical development, process efficiency and economic aspects of sorting and separation systems. 2) To design and simulate, through techno-economic analysis and material/energy flow modelling, alternative waste management systems which aim at increased material recovery and flexibility in utilization of waste-derived energy. 3) To evaluate the feasibility of waste management systems based on central sorting and identify the advantages and disadvantages of such systems in terms of economy, climate impacts and resource recovery compared to systems based on direct WtE. 4) To explore and quantify the significance of changing background conditions such as the overall Danish and European policy and ambitions for future renewable energy integration and climate change mitigation and how such changing background conditions influence the feasibility of central sorting compared to alternative systems. 5) To identify and assess the significance of conditional synergies and other indirect effects occurring in background systems as a consequence of waste management decisions.Through the findings of this work, it can be concluded that waste physical/mechanical processing and sorting technology have reached a high level of technical maturity, and play a crucial role both in sorting and preparation for recycling of source-separated recyclable materials, and the processing of mixed/residual MSW streams. The concept of central sorting is already applied successfully in numerous places around the world, as an efficient strategy for “material specific treatment”, meaning to gain access to the various material groups in mixed or residual MSW, such as: (1) recyclable materials, (2) biodegradable organic fractions, for dedicated biological treatment, and (3) high-energy content fractions, for production of waste-derived fuels. From a resource recovery perspective, a strong motivation for residual MSW central sorting is its potential to support, or even be an alternative to, source separation and separate collection for recyclable materials, in areas where such programs are difficult to implement or optimize, such as urban agglomerations.Alternative MSW management systems were simulated and evaluated, comprising numerous combinations of separate collection of mono- and commingled waste fractions as well as mixed residual fractions and comprising a variety of downstream treatment/handling approached to these fractions. All scenarios were, in turn, assessed and compared against a large variety of background system scenarios leading to a total of above a thousand waste management models. The aim was to create a robust platform for evaluating the feasibility of systems including central sorting against other systems, to understand the outcome of comparisons and their dependency on framework conditions and to establish a final ‘pattern’ of comparisons allowing a robust interpretation for decision making with respect to all aspects of feasibility, including aspects of resource recovery, energy efficiency, and climate impacts.Material recovery: The results reveal that very high recycling rates are possible, and that central sorting typically improves recycling rates for all material fractions except paper and cardboard. Further, with regard to the bio-waste fraction, there is an important issue of contamination/quality influencing the subsequent options for applying the bio-fraction.Energy efficiency: It was, further, found that the enhanced material recovery on the short-to-medium term does not happen at the expense of less energy recovery. On the contrary, when revealing the mechanisms of a liberal waste market leading to waste imports, the same or a higher amount of waste-derived energy could be supplied to the background energy system when including increased separate collection or central sorting. In a longer term perspective, systems which prioritized recovery of materials for recycling maintained higher GWP savings and were less vulnerable to the decreasing benefits from replacing energy produced in future background systems.Carbon footprint: The evaluation by carbon footprint (based on consequential LCA methodology), of reference (WtE) and alternative strategies to energy integration of waste derived biomethane and RDF, against different sets of background conditions representing the most probable future development of the Danish energy system, yielded a number of robust conclusions. In short-to-medium term, MSW management would see a decrease in GHG savings, consistent with the diminishing share of fossil fuels in the energy system being displaced by the energy recovered from the waste. The ability to maintain net waste-derived GHG savings from waste energy recovery in a longer term perspective is found to be determined by the ability to integrate waste based energy production in the surrounding energy system. Therefore, the flexibility of waste derived energy supply and its ability to displace peak energy production, based on remaining fossil fuels or increasingly biomass, becomes decisive to the resulting carbon footprint of MSW management. In a fully renewable background energy system, the nature of the marginal source for biomass would determine the magnitude of savings related to flexible waste-derived energy production. Systems based on central sorting, with production of storable RDF for intended utilization in the cold season in district heating networks, were indicated as especially relevant, and consistently attained net GW benefits in all modelled background situations superior to direct WtE. Implementation of strategies for increasing recycling and/or optimization of wastederived energy recovery in countries with self-sufficient waste management systems (such as Denmark) and high degree of WtE, can affect waste management operations in other European countries. Such indirect effects manifest themselves through market mechanisms, and are caused by direct consequences of such strategies on the utilization of existing waste treatment infrastructure, specifically capital-intensive, long-lived WtE infrastructure – i.e. if incineration capacity is released in a given WtE facility due to a separate collection scheme or the establishment of a central sorting facility, such capacity will soon be filled up by waste import. These effects are in most cases environmentally desirable, as a move up the waste hierarchy in a self-sufficient system seems to have the same implication in countries lacking treatment capacity, affecting marginal waste treatment (i.e. leading to reduction of landfilling). Moreover, short-to-medium term waste imports may act as a support mechanism to the gradual change in how waste is managed, from systems relying heavily on continuous WtE to systems prioritizing material recovery and storable waste-derived energy carriers
Central sorting systems in Municipal Solid Waste management
Full text linkAffaldsteknologier udvikler sig over tid og det samme gør de baggrundssystemer og rammevilkår som affaldssystemer afhænger af. Gennem de sidste, og sandsynligvis også de kommende, årtier vil den politiske udvikling således i væsentlig grad ændre rammerne for optimering af affaldssystemernes indretning.De mest afgørende fremtidige baggrundsbetingelser defineres især af tre politiske områder. For det første af stigende bestræbelser for en bedre styring af samfundets materiale-ressourcer, på vejen med en ’cirkulær økonomi’, herunder forhøjede mål for materialegenvinding. For det andet af en omfattende omlægning af energisystemet til vedvarende energi, motiveret af ønsker om fortsat god fremtidig forsyningssikkerhed såvel som reduceret klimapåvirkning. For det tredje af den affaldspolitiske udvikling selv, herunder forbud mod affaldsdeponering, skatter og afgifter og sidst men ikke mindst af den øgede liberalisering og udvikling af et internationalt marked for affaldshåndtering. Hvad angår materialegenvinding fra kommunalt affald, prioriterer den aktuelle europæiske affaldspolitik kildesortering og separat indsamling. Der er imidlertid væsentlige økonomiske og sociale begrænsninger ved denne tilgang, som kan udgøre et grundlag for innovative løsninger. Inden for rammerne af den sandsynlige udvikling af energisystemet vil den nuværende ensrettede affaldsforbrændingstilgang, som indebærer en ikke-fleksibel, kontinuert energigenvinding, miste sine nuværende klimafordele på længere sigt.Hidtidige metoder og praksis for systemanalyse, især livscyklusvurdering, LCA, repræsenterer og vurderer oftest affaldssektoren i et for forsimplet samspil med sine omgivelser med et minimum af fremtidig interaktion og systemeffekter, i de fleste tilfælde gennem inkonsistente metoder og statisk repræsentation af baggrundssystemerne, og deres utilstrækkelige evne til at afspejle konsekvenserne af beslutninger om implementering af forskellige affaldshåndteringsstrategier er kompromitterende for deres brug i beslutningsstøtte. Der er derfor et behov for videreudvikling af metoder til at modellere effekten af interaktioner med omgivende systemer, herunder en involvering af økonomiske modelleringsmetoder.Dette PhD arbejde har undersøgt den rolle og de implikationer mekanisk forsortering og central sortering kan have som en nøgleteknologi i strategier for optimeret ressource- og energigenvinding og minimering af klimapåvirkningen fraaffaldshåndtering i lyset af fremtidens rammebetingelser. Projektets overordnede mål kan nedbrydes i fem del-mål:1) At gennemgå og udbygge den eksisterende viden om fysisk/mekanisk behandling af kommunalt affald, inklusive forståelsen af det nuværende stade for teknisk udvikling, proces-effektivitet og økonomiske aspekter af sorterings- og separations-systemer 2) Gennem teknisk-økonomisk analyse og materiale- og energiflow modellering at simulere og designe alternative affaldssystemers, som sigter mod øget materialegenvinding og øget fleksibilitet i produktionen af affalds-relateret energi 3) At vurdere egnetheden og konkurrencedygtigheden af affaldssystemer med central sortering og identificere de fordele og ulemper sådanne systemer har i form af økonomi, klimapåvirkning og ressourcegenvinding sammenlignet med systemer med affaldsforbrænding 4) At afklare og kvantificere, hvor meget ændrede rammevilkår betyder for de relative fordele og ulemper ved central sortering, herunder Danmarks og EU's politik og ambitioner for vedvarende energi og reduktion af klimapåvirkning 5) At identificere og vurdere betydningen af synergi og andre indirekte effekter i baggrundssystemerne, der opstår som konsekvens af beslutninger om affaldshåndteringErkendelserne fra dette PhD arbejde peger på, at fysisk/mekanisk processering og sortering af kommunalt affald har nået et teknisk modent niveau og spiller en afgørende rolle i både sortering og forbehandling til genvinding af kildesorterede genanvendelige materialer såvel som af blandet rest-affald.Central sortering er allerede anvendt med succes flere steder verden over som en effektiv måde at genvinde de forskellige materialegrupper i kommunalt affald, herunder genanvendelige materialer, bionedbrydeligt organisk affald til særskilt biologisk behandling samt en mere energitæt ’refuse derived fuel’, RDF. Fra et ressourceperspektiv er en stærk motivation for central sortering denne tekniks potentiale for at supplere eller helt erstatte kildesortering og separat indsamling af genanvendelige materialer i områder, hvor sådan indsamling er vanskelig, så som tæt bymæssig bebyggelse.Gennem PhD studiet er simuleret og vurderet et stort antal alternative systemer til håndtering af kommunalt affald, herunder mange kombinationer af separat indsamling af mono-fraktioner, blandende fraktioner og restaffald og mange forskellige teknikker til videre behandling af disse fraktioner. Alle scenarier blev desuden vurderet og sammenlignet på baggrund af et stort antal forskellige scenarier for baggrundssystemerne, og i alt blev opstillet og sammenlignet mere end tusind forskellige affaldssystem modeller. Formålet med denne store varietet var at skabe et robust sammenligningsgrundlag og at forstå, hvordan sammenligningen afhænger af antagelser om fremtidige rammevilkår, for herigennem at skabe et ’mønster’ af resultater for alternativernes relative fordele og ulemper mht. materialegenvinding, energieffektivitet og klimapåvirkning.Materialegenvinding: Resultaterne peger på et højt genvindingspotentiale generelt og på, at systemer med central sortering har den højeste materialegenvinding for alle materialekategorier på nær papir og pap. Mht. bio-affald peges på vigtigheden af kontaminering/kvalitet af den fraseparerede bio-fraktion for den videre anvendelse af fraktionen.Energieffektivitet: Studiet viser, at øget materialegenvinding fra separat indsamling eller central sortering – i affaldsoplandet for et forbrændingsanlæg – ikke sker på bekostning af ringere energigenvinding. Tværtimod blev det påvist, at der opnås samme eller højere energigenvinding, når der tages højde for markedsmekanismerne fra det liberaliserede marked for affaldshåndtering i EU. På længere sigt vil systemer, der prioriterer højere materialegenvinding, bevare en større klimafordel, idet de er mindre følsomme for den faldende fordel ved energifortrængning, der følger af udviklingen mod vedvarende energi i energisystemet.Carbon footprint: Evalueringen af carbon footprint baseredes på konsekvens-LCA, og sammenligningen mellem reference-systemet med affaldsforbrænding og alternative strategier for produktion af bio-methan fra bio-affaldet og RDF fra restaffaldet i fremtidens vedvarende energisystem gav en række robuste konklusioner. På kort til mellemlangt sigt falder klimafordelene ved energigenvinding fra affaldet som nævnt proportionalt med, at den fortrængte energi i energisystemet gradvis ændres til vedvarende energi. Affaldssystemets evne til at opretholde en netto klimagevinst er således fundet at afhænge af, hvor godt energigenvindingen fra affaldet kan integreres i den fluktuerende vedvarende energiproduktion. Fleksibiliteten af energigenvindingen fra affaldet og dens evne til at erstatte spidslast el og varme (dvs. de teknologier, der anvendes, når vinden ikke blæser) bliver derfor afgørende for klimagevinsten fra affaldshåndteringen. Sådan spidslast vil på kort til mellemlangt sigt sandsynligvis være baseret på fossile brændsler og på længere sigt på biomasse. I et vedvarende energi system vil det således være karakteren og oprindelsen af den marginale biomasse, der afgør hvor stor klimagevinst, der er fra fleksibel affalds-baseret energi-genvinding.Systemer med central sortering med produktion af et lagerstabilt RDF til brug for fjernvarme til spidslast i vintersæsonen, blev fundet klimamæssigt særligt attraktive og blev fundet at opretholde netto klimagevinster og at være bedre end konventionel affaldsforbrænding under alle baggrundsbetingelser.Specielt for Danmark, men også relevant for andre lande med stor animalsk produktion i landbruget, er der store klimafordele og sandsynligvis også økonomiske fordele ved at anvende kildesorteret bio-affald som co-substrat i landbrugs-biogasanlæg baseret på husdyrgødning. Klimagevinsten opstår ved enten 1) at tilvejebringelsen at et co-substrat muliggør mere biogas på husdyrgødning og derved medfører mindre udledning af klimagasser fra konventionel håndtering af husdyrgødning eller 2) at bio-affaldet erstatter andre co-substrater, mest sandsynligt energiafgrøder, og dermed undgår den klimabelastninger, der er forbundet med disse.Implementeringen af øget materialegenvinding i lande med fuld affaldsbehandlingskapacitet, herunder fuld forbrændingskapacitet, som fx Danmark, kan påvirke et stigende internationalt marked for affaldshåndtering og dermed affaldshåndteringen i andre lande. Når affaldsstrømme kanaliseres væk fra investeringstung, eksisterende infrastruktur med lang restlevetid som affaldsforbrændingsanlæg, fx via separat indsamling eller central sortering til øget materialegenvinding, udbydes dennes kapacitet på markedet og affald importeres. Det afføder, at den marginale affaldshåndtering på markedet undgås, og dette er deponi. Sådanne kaskade-effekter er i de fleste tilfælde miljømæssigt fordelagtige. Affaldsimport kan på kort til mellemlangt sigt fungere som en økonomisk favorabel overgang i en gradvis afvikling af affaldsforbrænding, idet importeret affald kan understøtte eksisterende forbrændingsanlæg i deres restlevetid, mens investering i ny kapacitet undlades. Waste treatment technologies develop over time, and so do background conditions on which waste management systems rely. During the last and expectedly also the coming decades, political developments have and will, thus, significantly change the framework conditions for optimizing waste management.The dominating future background conditions have been found to be defined especially by the development within three policy areas. Firstly, by increased efforts to ensure a proper management of material resources, providing stepping stones towards a “circular economy”, including enhanced targets for material recovery and recycling. Secondly, an increased integration of renewable energy in energy systems, motivated by objectives both to ensure energy supply security and to mitigate adverse impacts of global warming. Thirdly, by waste management policies themselves, including regulations like banning landfilling, schemes on taxes, fees and subsidies and last but not least, the liberalization and development of an international market for waste management services.With regard to materials recovery for recycling from municipal solid waste (MSW), current European waste policy prioritizes source separation and separate collection. However, there are noticeable economic and social limitations with this approach, which motivate a search for innovative solutions. Within the likely (and politically targeted) development of background energy production, the current “one size fits all” approach towards waste-to-energy (WtE), through continuous waste incineration, is likely to see its current climate benefits compromised in the long term.Current systems analysis methods and practices and specifically waste LCA models most often represent and evaluate the waste management sector in a much too simplistic interaction with its surroundings, accounting for a minimum of probable future system interactions/effects, many times through inconsistent methods and static representations of background systems. Their insufficiency in taking account of consequences of decisions towards implementation of different waste management strategies can compromise them as decision-supporting tools. As such, there is a need for advances in methodological aspects related to modelling effects/interactions with surrounding systems, including better convergence with economic modelling methods.This PhD work investigated the role and implications of mechanical pre-treatment and central sorting as a key waste management technology for strategies to achieve both resource and energy recovery optimizations and to minimize climate impacts of waste management in the context of future framework conditions. The goal of the work was broken down to five main objectives:1) To review and expand the knowledge base on physical/mechanical treatment of municipal waste streams, including current state in technical development, process efficiency and economic aspects of sorting and separation systems. 2) To design and simulate, through techno-economic analysis and material/energy flow modelling, alternative waste management systems which aim at increased material recovery and flexibility in utilization of waste-derived energy. 3) To evaluate the feasibility of waste management systems based on central sorting and identify the advantages and disadvantages of such systems in terms of economy, climate impacts and resource recovery compared to systems based on direct WtE. 4) To explore and quantify the significance of changing background conditions such as the overall Danish and European policy and ambitions for future renewable energy integration and climate change mitigation and how such changing background conditions influence the feasibility of central sorting compared to alternative systems. 5) To identify and assess the significance of conditional synergies and other indirect effects occurring in background systems as a consequence of waste management decisions.Through the findings of this work, it can be concluded that waste physical/mechanical processing and sorting technology have reached a high level of technical maturity, and play a crucial role both in sorting and preparation for recycling of source-separated recyclable materials, and the processing of mixed/residual MSW streams. The concept of central sorting is already applied successfully in numerous places around the world, as an efficient strategy for “material specific treatment”, meaning to gain access to the various material groups in mixed or residual MSW, such as: (1) recyclable materials, (2) biodegradable organic fractions, for dedicated biological treatment, and (3) high-energy content fractions, for production of waste-derived fuels. From a resource recovery perspective, a strong motivation for residual MSW central sorting is its potential to support, or even be an alternative to, source separation and separate collection for recyclable materials, in areas where such programs are difficult to implement or optimize, such as urban agglomerations.Alternative MSW management systems were simulated and evaluated, comprising numerous combinations of separate collection of mono- and commingled waste fractions as well as mixed residual fractions and comprising a variety of downstream treatment/handling approached to these fractions. All scenarios were, in turn, assessed and compared against a large variety of background system scenarios leading to a total of above a thousand waste management models. The aim was to create a robust platform for evaluating the feasibility of systems including central sorting against other systems, to understand the outcome of comparisons and their dependency on framework conditions and to establish a final ‘pattern’ of comparisons allowing a robust interpretation for decision making with respect to all aspects of feasibility, including aspects of resource recovery, energy efficiency, and climate impacts.Material recovery: The results reveal that very high recycling rates are possible, and that central sorting typically improves recycling rates for all material fractions except paper and cardboard. Further, with regard to the bio-waste fraction, there is an important issue of contamination/quality influencing the subsequent options for applying the bio-fraction.Energy efficiency: It was, further, found that the enhanced material recovery on the short-to-medium term does not happen at the expense of less energy recovery. On the contrary, when revealing the mechanisms of a liberal waste market leading to waste imports, the same or a higher amount of waste-derived energy could be supplied to the background energy system when including increased separate collection or central sorting. In a longer term perspective, systems which prioritized recovery of materials for recycling maintained higher GWP savings and were less vulnerable to the decreasing benefits from replacing energy produced in future background systems.Carbon footprint: The evaluation by carbon footprint (based on consequential LCA methodology), of reference (WtE) and alternative strategies to energy integration of waste derived biomethane and RDF, against different sets of background conditions representing the most probable future development of the Danish energy system, yielded a number of robust conclusions. In short-to-medium term, MSW management would see a decrease in GHG savings, consistent with the diminishing share of fossil fuels in the energy system being displaced by the energy recovered from the waste. The ability to maintain net waste-derived GHG savings from waste energy recovery in a longer term perspective is found to be determined by the ability to integrate waste based energy production in the surrounding energy system. Therefore, the flexibility of waste derived energy supply and its ability to displace peak energy production, based on remaining fossil fuels or increasingly biomass, becomes decisive to the resulting carbon footprint of MSW management. In a fully renewable background energy system, the nature of the marginal source for biomass would determine the magnitude of savings related to flexible waste-derived energy production. Systems based on central sorting, with production of storable RDF for intended utilization in the cold season in district heating networks, were indicated as especially relevant, and consistently attained net GW benefits in all modelled background situations superior to direct WtE. Implementation of strategies for increasing recycling and/or optimization of wastederived energy recovery in countries with self-sufficient waste management systems (such as Denmark) and high degree of WtE, can affect waste management operations in other European countries. Such indirect effects manifest themselves through market mechanisms, and are caused by direct consequences of such strategies on the utilization of existing waste treatment infrastructure, specifically capital-intensive, long-lived WtE infrastructure – i.e. if incineration capacity is released in a given WtE facility due to a separate collection scheme or the establishment of a central sorting facility, such capacity will soon be filled up by waste import. These effects are in most cases environmentally desirable, as a move up the waste hierarchy in a self-sufficient system seems to have the same implication in countries lacking treatment capacity, affecting marginal waste treatment (i.e. leading to reduction of landfilling). Moreover, short-to-medium term waste imports may act as a support mechanism to the gradual change in how waste is managed, from systems relying heavily on continuous WtE to systems prioritizing material recovery and storable waste-derived energy carriers
SOCIOLOGIA ELITELOR. ABORDĂRI CLASICE ȘI CONTEMPORANE. INSTITUTUL EUROPEAN, IAȘI, 2023. CIPRIAN IFTIMOAEI
Full text linkThe volume Sociologia elitelor. Abordări clasice și contemporane (The Sociology of Elites. Classical and Contemporary Approaches) fits into a relatively recent series of studies within the Romanian social sciences dedicated to examining elites in the context of transition, democratic consolidation, and good governance. The author brings together both classical and contemporary approaches to the study of elites, organizing them into four major schools of sociopolitical thought: the classical sociology of elites, the radical (critical) sociology of elites, elite pluralism, and democratic elitism. Ciprian Iftimoaei’s work makes an important contribution not only by systematizing elitist theories but also by integrating them into a coherent sociological framework applied to the Romanian post-communist context. The author succeeds in creating a dialogue between Western paradigms of elite studies and the Romanian sociological tradition, building a bridge between theoretical reflection and empirical analysis of contemporary political elites. Moreover, his approach is distinguished by the ability to operationalize key concepts such as power, domination, circulation, and elite consensus, thus providing a sociological model that can also be applied to other areas of political analysis. Conceptual rigor, balance between description and interpretation, and the combined use of qualitative and quantitative methods make this volume a methodological benchmark for elite research in Romania
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