949 resultados para life-cycle models
Resumo:
A causa del riscaldamento globale, tutti i settori produttivi sono incentivati ad attuare strategie e tecnologie volte a ridurre le emissioni climalteranti. Per il settore agricolo, una gestione più sostenibile del suolo permetterebbe di rimuovere CO2 dall’atmosfera, stoccandola come C organico nel suolo. Il presente studio si pone l’obiettivo di quantificare gli impatti della produzione dell’uva e del vino imbottigliato dal punto di vista degli aspetti ambientali più rilevanti, approfondendo particolarmente il cambiamento climatico attraverso la metodologia Life Cycle Assessment (LCA). Inoltre, attraverso la determinazione delle dinamiche del C organico nel suolo mediante il modello RothC, lo studio cerca di capire se l'integrazione dei risultati di uno studio LCA con quelli del modello RothC possano fornire informazioni aggiuntive utili a un miglioramento della performance ambientale del prodotto agricolo. Il caso studio riguarda due aziende vitivinicole, situate in Emilia-Romagna che attuano due diverse tipologie di gestione (naturale e convenzionale). La metodologia LCA è stata applicata ad entrambi gli scenari selezionando i parametri metodologici più appropriati a seconda dello scenario in esame, e.g. i confini del sistema e l’unità funzionale, mentre, il modello RothC è stato applicato unicamente alla fase di coltivazione dell’uva. I risultati LCA mostrano le migliori prestazioni per la produzione dell’uva dell’azienda naturale per quasi tutte le categorie d’impatto, incluso il cambiamento climatico. Nella produzione del vino imbottigliato, la fase di coltivazione e quella di imbottigliamento risultano le più impattanti. I risultati di RothC evidenziano invece migliori prestazioni da parte dell’azienda convenzionale. L’integrazione dei risultati LCA con quelli di RothC rappresentano dunque un’operazione cruciale nel determinare quale sia l’effettivo impatto delle aziende agricole sul cambiamento climatico e come migliorarlo in futuro.
Resumo:
Lo studio ha applicato la metodologia Life Cycle Assessment (LCA) con l’obiettivo di valutare i potenziali impatti ambientali derivanti dalla coltivazione dell’uva in due aziende a conduzione convenzionale del ravennate, denominate DZ e NG. Successivamente è stato applicato il modello RothC per simulare scenari sulla variazione del Soil Organic Carbon (SOC) e valutare in che misura le diverse pratiche agronomiche di gestione del suolo influenzino la variazione del SOC e la relativa emissione di CO2. Infine, i risultati dell’LCA sono stati integrati con quelli del modello RothC. Gli esiti dell’LCA indicano che, generalmente, sui diversi aspetti ambientali l’azienda DZ ha impatti superiori a quelli di NG soprattutto a causa di un maggiore utilizzo di fertilizzanti e pesticidi. Per quanto riguarda il contributo al riscaldamento globale (GWP), DZ mostra un impatto circa doppio di quello di NG. Il modello RothC ha individuato quali pratiche culturali aumentano il SOC mitigando le emissioni di CO2eq., in particolare: l’inerbimento perenne, la scelta di forme di allevamento con elevata produzione di residui culturali e l’utilizzo di ammendanti. L’integrazione dei valori dei due strumenti ha permesso di ottenere un bilancio globale di CO2eq. in cui le emissioni totali rispetto al GWP aumentano in DZ e diminuiscono in NG, portando a un impatto di DZ circa tre volte superiore rispetto a quello di NG. Fertilizzazione, potatura e lavorazione del suolo sono pratiche considerate nel calcolo del GWP in termini di consumo ed emissione dei processi produttivi, ma non come input di carbonio fornibili al suolo, determinando sovra o sottostima delle effettive emissioni di CO2eq. Questo studio dimostra l’utilità di incentivare la diffusione dell’applicazione integrata dei due strumenti nel settore viticolo, determinante per la comprensione e quantificazione delle emissioni di CO2 associate alla fase di coltivazione, sulla quale quindi indirizzare ottimizzazioni e approfondimenti.
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Increasing environmental awareness has been a significant driving force for innovations and process improvements in different sectors and the field of chemistry is not an outlier. Innovating around industrial chemical processes in line with current environmental responsibilities is however no mean feat. One of such hard to overhaul process is the production of methyl methacrylate (MMA) commonly produced via the acetone cyanohydrin (ACH) process developed back in the 1930s. Different alternatives to the ACH process have emerged over the years and the Alpha Lucite process has been particularly promising with a combined plant capacity of 370,000 metric tonnes in Singapore and Saudi Arabia. This study applied Life Cycle Assessment methodology to conduct a comparative analysis between the ACH and Lucite processes with the aim of ascertaining the effect of applying principles of green chemistry as a process improvement tool on overall environmental impacts. A further comparison was made between the Lucite process and a lab-scale process that is further improvement on the former, also based on green chemistry principles. Results showed that the Lucite process has higher impacts on resource scarcity and ecosystem health whereas the ACH process has higher impacts on human health. On the other hand, compared to the Lucite process the lab-scale process has higher impacts in both the ecosystem and human health categories with lower impacts only in the resource scarcity category. It was observed that the benefits of process improvements with green chemistry principles might not be apparent in some categories due to some limitations of the methodology. Process contribution analysis was also performed and it revealed that the contribution of energy is significant, therefore a sensitivity analysis with different energy scenarios was performed. An uncertainty analysis using Monte Carlo analysis was also performed to validate the consistency of the results in each of the comparisons.
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In this Thesis, a life cycle analysis (LCA) of a biofuel cell designed by a team from the University of Bologna was done. The purpose of this study is to investigate the possible environmental impacts of the production and use of the cell and a possible optimization for an industrial scale-up. To do so, a first part of the paper was devoted to studying the present literature on biomass, and fuel cell treatments and then LCA studies on them. The experimental part presents the work done to create the Life Cycle Inventory and Life Cycle Impact Assessment. Several alternative scenarios were created to study process optimization. Reagents and energy supply were changed. To examine whether this technology can be competitive, a comparison was made with some biofuel cell use scenarios with traditional biomass treatment technologies. The result of this study is that this technology is promising from an environmental point of view in case it is possible to recover nutrients in output, without excessive energy consumption, and to minimize the use of energy used to prepare the solution.
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Although standard incomplete market models can account for the magnitude of the rise in consumption inequality over the life cycle, they generate unrealistically concave age pro.les of consumption inequality and unrealistically less wealth inequality. In this paper, I investigate the role of discount rate heterogeneity on consumption inequality in the context of incomplete market life cycle models. The distribution of discount rates is estimated using moments from the wealth distribution. I .nd that the model with heterogeneous income pro.les (HIP) and discount rate heterogeneity can successfully account for the empirical age pro.le of consumption inequality, both in its magnitude and in its non-concave shape. Generating realistic wealth inequality, this simulated model also highlights the importance of ex ante heterogeneities as main sources of life time inequality.
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Unemployment rates in developed countries have recently reached levels not seenin a generation, and workers of all ages are facing increasing probabilities of losingtheir jobs and considerable losses in accumulated assets. These events likely increasethe reliance that most older workers will have on public social insurance programs,exactly at a time that public finances are suffering from a large drop in contributions.Our paper explicitly accounts for employment uncertainty and unexpectedwealth shocks, something that has been relatively overlooked in the literature, butthat has grown in importance in recent years. Using administrative and householdlevel data we empirically characterize a life-cycle model of retirement and claimingdecisions in terms of the employment, wage, health, and mortality uncertainty facedby individuals. Our benchmark model explains with great accuracy the strikinglyhigh proportion of individuals who claim benefits exactly at the Early RetirementAge, while still explaining the increased claiming hazard at the Normal RetirementAge. We also discuss some policy experiments and their interplay with employmentuncertainty. Additionally, we analyze the effects of negative wealth shocks on thelabor supply and claiming decisions of older Americans. Our results can explainwhy early claiming has remained very high in the last years even as the early retirementpenalties have increased substantially compared with previous periods, andwhy labor force participation has remained quite high for older workers even in themidst of the worse employment crisis in decades.
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The objective of the thesis is to enhance understanding of the evolution of convergence. Previous research has shown that the technological interfaces between distinct industries are one of the major sources of new radical cross-industry innovations. Despite the fact that convergence in industry evolution has attracted a substantial managerial interest, the conceptual confusion within the field of convergence exists. Firstly, this study clarifies the convergence phenomenon and its impact to industry evolution. Secondly, the study creates novel patent analysis methods to analyze technological convergence and provide tools for anticipating the early stages of convergence. Overall the study combines the industry evolution perspective and the convergence view of industrial evolution. The theoretical background for the study consists of the industry life cycle theories, technology evolution, and technological trajectories. The study links several important concepts in analyzing industry evolution, technological discontinuities, path-dependency, technological interfaces as a source of industry transformation, and the evolutionary stagesof convergence. Based on reviewing the literature a generic understanding of industry transformation and industrial dynamics was generated. In the convergence studies, the theoretical basis is in the discussion of different convergence types and their impacts on industry evolution, and in anticipating and monitoring the stages of convergence. The study is divided in two parts. The first part gives a general overview, and the second part comprises eight research publications. Our case study is based historically on two very distinct industries of the paper and electronics companies as a test environment to evaluate the importance of emerging business sectors and technological convergence as a source of industry transformation. Both qualitative and quantitative research methodology are utilized. The results of this study reveal that technological convergence and complementary innovations from different fields have significant effect to the emerging new business sector formation. The patent-based indicators in the analysis of technological convergence can be utilized on analyzing technology competition, capability and competence development, knowledge accumulation, knowledge spill-overs, and technology-based industry transformation. The patent-based indicators can provide insights to the future competitive environment. Results and conclusions from empirical part seem not be in conflict with real observations in the industry.
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Tiivistelmä: Elinkaaren palvelumallit ovat suosittuja julkisten palveluiden hankintamuotoja Iso-Britanniassa. PPP–malli on yksi monista julkisten palvelujen kumppanuusmalleista, josta on tullut joissakin kunnissa yhä suositumpi hankintamalli myös Suomessa. Tämä on seurausta kuntien tiukasta taloustilanteesta, jossa PPP–hankkeen katsotaan mahdollistavan julkisen sektorin investoinnit joutumatta leikkaamaan muita pakollisia hankintoja. Kuitenkin koko elinkaaren kattavat palvelutarjonnan hankintamallit ovat vielä melko uusia malleja ja meillä on tarve löytää toimivia sopimusmalleja ja käytäntöjä, jotta hankkeista saadaan rakennusliikettä kiinnostavia liiketoimintamalleja. Ulkomailla elinkaarihankkeista on tehty monia tutkimuksia ja konsultit ovat kääntäneet niitä omiin tarkoituksiinsa sopiviksi. Kuitenkin Suomen lainsäädäntö on erilainen julkisten palveluiden tuottamisessa, erityisesti lakisääteisissä terveydenhuoltopalveluissa, vesi- ja jätevesihuollossa, vankeinhoidossa, ja niin edelleen. Tästä näkökulmasta ulkomailla tehdyt tutkimukset eivät sellaisenaan sovi Suomeen käytettäviksi. Esimerkiksi tutkimuksissa esitetään, että elinkaarihankkeet tuottavat pitkän aikavälin kassavirtaan, mutta tämä etu koskee vain rahoittaja ja kiinteistöpalvelu yrityksiä - ei rakennusyritystä. Tutkimuksissa mainitaan myös muista elinkaarihankkeiden mahdollisuuksista, jotka jäävät kuitenkin rakennusliikkeen näkökulmasta epäselviksi. Perinteisiin rakennuttamisen malleihin verrattuna elinkaarihankkeiden sopimusmenettelyt ovat monimutkaisempia sekä aikaa vievempiä ja sopijaosapuolten yhteistyö elinkaarihankkeissa on välttämätöntä. Käytännössä elinkaarihankkeiden riskienjako nähdään julkisen sektorin ja yksityisen sektorin välillä yksipuoliseksi. Jotta elinkaarimalli yleistyisi Suomessa, niin elinkaarisopimuksen riskienjaosta on tehtävä tasapuolinen ja käyttäjä pitää saada myös riskejä kantamaan. Tässä työssä keskitytään arvioimaan elinkaarimallien keskeisiä menestystekijöitä ja riskitekijöitä ja löytää mahdollisia tapoja tehdä hankintaprosessista helppoa ja sujuvaa. Samalla yritetään selvittää, miten elinkaarihankkeesta saadaan rakennusliikkeen kannalta menestyvää liiketoimintaa. Johtopäätökset perustuvat aikaisempiin tutkimuksiin ja empiiriseen tapaustutkimukseen. Työssä arvioidaan niitä seikkoja, jotka vaikuttavat yksityisen sektorin tarjouspäätökseen. Arvioinnissa erotetaan toisistaan kolme erillistä riskitekijää; tarjouksen tekemisen riskit, rakennushankkeen riskit ja elinkaaren aikaiset riskit. Työssä todetaan, että aikaisemmat tutkimukset ovat riittämättömiä rakennusliikkeen riskien arvioimiseen.
Resumo:
The purpose of this study was to explore software development methods and quality assurance practices used by South Korean software industry. Empirical data was collected by conducting a survey that focused on three main parts: software life cycle models and methods, software quality assurance including quality standards, the strengths and weaknesses of South Korean software industry. The results of the completed survey showed that the use of agile methods is slightly surpassing the use of traditional software development methods. The survey also revealed an interesting result that almost half of the South Korean companies do not use any software quality assurance plan in their projects. For the state of South Korean software industry large number of the respondents thought that despite of the weakness, the status of software development in South Korea will improve in the future.
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We identify conditions under which preferences over sets of consumption opportunities can be reduced to preferences over bundles of \"commodities\". We distinguish ordinal bundles, whose coordinates are defined up to monotone transformations, from cardinal bundles, whose coordinates are defined up to positive linear transformations only.
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Populations of Lesser Scaup (Aythya affinis) have declined markedly in North America since the early 1980s. When considering alternatives for achieving population recovery, it would be useful to understand how the rate of population growth is functionally related to the underlying vital rates and which vital rates affect population growth rate the most if changed (which need not be those that influenced historical population declines). To establish a more quantitative basis for learning about life history and population dynamics of Lesser Scaup, we summarized published and unpublished estimates of vital rates recorded between 1934 and 2005, and developed matrix life-cycle models with these data for females breeding in the boreal forest, prairie-parklands, and both regions combined. We then used perturbation analysis to evaluate the effect of changes in a variety of vital-rate statistics on finite population growth rate and abundance. Similar to Greater Scaup (Aythya marila), our modeled population growth rate for Lesser Scaup was most sensitive to unit and proportional change in adult female survival during the breeding and non-breeding seasons, but much less so to changes in fecundity parameters. Interestingly, population growth rate was also highly sensitive to unit and proportional changes in the mean of nesting success, duckling survival, and juvenile survival. Given the small samples of data for key aspects of the Lesser Scaup life cycle, we recommend additional research on vital rates that demonstrate a strong effect on population growth and size (e.g., adult survival probabilities). Our life-cycle models should be tested and regularly updated in the future to simultaneously guide science and management of Lesser Scaup populations in an adaptive context.
Resumo:
An important feature of life-cycle models is the presence of uncertainty regarding one’s labor income. Yet this issue, long recognized in different areas, has not received enough attention in the optimal taxation literature. This paper is an attempt to fill this gap. We write a simple 3 period model where agents gradually learn their productivities. In a framework akin to Mirrlees’ (1971) static one, we derive properties of optimal tax schedules and show that: i) if preferences are (weakly) separable, uniform taxation of goods is optimal, ii) if they are (strongly) separable capital income is to rate than others forms of investiment.
Resumo:
Este trabalho apresenta uma revisão dos principais modelos de ciclo de vida para posteriormente discutir a necessidade de um modelo específico para o ambiente brasileiro. Apesar de toda discussão sobre a crise na instituição família em função das amplas mudanças ocorridas na sociedade contemporânea, tais como o aumento dos domicílios unipessoais, das famílias chefiadas por mulheres, da média de idade ao se casar, de casais que convivem no mesmo domicílio sem necessariamente estarem casados, da participação da mulher no mercado de trabalho e do crescente poder de compra dos domicílios, o conceito "família" vem se flexibilizando para refletir as transições da rígida estrutura familiar nuclear para novos modelos familiares e os estilos de vida associados a eles. O desafio passa a ser um olhar minucioso para as necessidades específicas desta diversidade de arranjos familiares para uma melhor compreensão dos seus desejos e motivações, bem como as mudanças no decorrer dos vários estágios do ciclo de vida. O presente estudo procurou explorar o construto ciclo de vida familiar como uma importante ferramenta de segmentação, a partir da definição de padrões de consumo de acordo com os principais eventos da vida do individuo e da família. Para verificar a utilidade do modelo desenvolvido, será apresentado um teste feito a partir dos micro dados de uma pesquisa feita pelo Instituto Brasileiro de Geografia e Estatística em 2002 e 2003. Uma das grandes contribuições deste trabalho é o esforço em desenvolver uma teoria de Marketing, na área de segmentação de mercados, ancorada na realidade brasileira, ao invés de simplesmente copiar modelos desenvolvidos em outros países.
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In contrast to other approaches that provide methodological guidance for ontology engineering, the NeOn Methodology does not prescribe a rigid workflow, but instead it suggests a variety of pathways for developing ontologies. The nine scenarios proposed in the methodology cover commonly occurring situations, for example, when available ontologies need to be re-engineered, aligned, modularized, localized to support different languages and cultures, and integrated with ontology design patterns and non-ontological resources, such as folksonomies or thesauri. In addition, the NeOn Methodology framework provides (a) a glossary of processes and activities involved in the development of ontologies, (b) two ontology life cycle models, and (c) a set of methodological guidelines for different processes and activities, which are described (a) functionally, in terms of goals, inputs, outputs, and relevant constraints; (b) procedurally, by means of workflow specifications; and (c) empirically, through a set of illustrative examples.
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Life cycle models have become important in explaining the changing size structure of firms based on the carrying capacity of regions or industries. In particular, the population ecology model predicts stages of growth, maturity and eventually decline in the number of firms in an industry. There has been criticism of such models because of their focus on external variables as pre-determinants of the potential for enterprise development. This paper attempts to reconcile the external focus of the population ecology model with relevant internal management factors in enterprise development. A survey was conducted of Australian services exporters, and the results not only confirm the existence of four separate life cycle stages in the population ecology model, but also identify the external and internal variables that are strategically relevant at each of the stages. The findings provide potentially useful information in a range of contexts including the design of small business assistance as well a providing “guide posts” to entrepreneurs engaged in enterprise development.