940 resultados para life cycle assessment bio-fuel cell biomass waste LCA biowaste valorization


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Computer software plays an important role in business, government, society and sciences. To solve real-world problems, it is very important to measure the quality and reliability in the software development life cycle (SDLC). Software Engineering (SE) is the computing field concerned with designing, developing, implementing, maintaining and modifying software. The present paper gives an overview of the Data Mining (DM) techniques that can be applied to various types of SE data in order to solve the challenges posed by SE tasks such as programming, bug detection, debugging and maintenance. A specific DM software is discussed, namely one of the analytical tools for analyzing data and summarizing the relationships that have been identified. The paper concludes that the proposed techniques of DM within the domain of SE could be well applied in fields such as Customer Relationship Management (CRM), eCommerce and eGovernment. ACM Computing Classification System (1998): H.2.8.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A társadalombiztosítási nyugdíjrendszer finanszírozása pusztán a demográfiai folyamatok következtében is jelentős terhet ró majd a költségvetésére, amin a különböző parametrikus és paradigmatikus nyugdíjreformok enyhíthetnek. A reformok azonban hosszú távon olyan viselkedési, munkakínálati reakciókat válthatnak ki, amelyek alapvetően változtatják meg a költségvetési hatásokat. Az 1999 és 2009 között Magyarországon megfigyelhető átlagos munka- és nyugdíjkorprofilok bemutatása után arra tettünk kísérletet, hogy mikroökonómiai alapon határozzuk meg néhány alapvető parametrikus nyugdíjreformnak a férfiak életciklus-munkakínálatára gyakorolt hatását. A modell paramétereit a magyar gazdaság 1999 és 2009 közötti jellemzőinek megfelelően kalibráltuk. Eredményeink szerint a helyettesítési ráta csökkentése, a nyugdíjkorhatár emelése és a svájci indexálás árindexálásra cserélése összességében számottevően növeli az egyes képzettségi csoportok munkakínálatát, s a fiatalabb korosztályok javára csoportosítja át az életciklus-munkakínálatot, míg a nyugdíj kiszámításához figyelembe vett évek számának megváltoztatása nem hoz jelentős aggregált hatást, és nem jár a munkakínálat korcsoportok közötti átcsoportosításával. ____ Financing the social-security pension system will weigh heavily on the government budget in developed countries, merely through the projected demographic processes. The burden could be eased by various parametric and paradigmatic pension reforms, but in the long run such reforms may trigger behavioural, labour-supply responses, which may alter the budgetary effects fundamentally. Having described the average work and pension profiles in Hungary between 1999 and 2009, the authors use a microeconomic approach in an attempt to assess the effect of certain parametric pension reforms on the life-cycle labour supply of males. The parameters for the model were calibrated for the characteristics of the Hungarian economy. The results show that decreasing the replacement rate, increasing the retirement age and replacing Swiss indexation of pensions by price indexation cause a considerable increase in the labour supply of all education-level groups, whereas changing the number of years considered in computing pensions does not have a significant aggregate effect. While introducing price indexation increases the labour supply of all cohorts by the same amount, the other reforms reallocate the life-cycle labour supply, mainly towards younger age-groups.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Deccan Trap basalts are the remnants of a massive series of lava flows that erupted at the K/T boundary and covered 1-2 million km2 of west-central India. This eruptive event is of global interest because of its possible link to the major mass extinction event, and there is much debate about the duration of this massive volcanic event. In contrast to isotopic or paleomagnetic dating methods, I explore an alternative approach to determine the lifecycle of the magma chambers that supplied the lavas, and extend the concept to obtain a tighter constraint on Deccan’s duration. My method relies on extracting time information from elemental and isotopic diffusion across zone boundaries in individual crystals. I determined elemental and Sr-isotopic variations across abnormally large (2-5 cm) plagioclase crystals from the Thalghat and Kashele “Giant Plagioclase Basalts” from the lowermost Jawhar and Igatpuri Formations respectively in the thickest Western Ghats section near Mumbai. I also obtained bulk rock major, trace and rare earth element chemistry of each lava flow from the two formations. Thalghat flows contain only 12% zoned crystals, with 87 Sr/86Sr ratios of 0.7096 in the core and 0.7106 in the rim, separated by a sharp boundary. In contrast, all Kashele crystals have a wider range of 87Sr/86Sr values, with multiple zones. Geochemical modeling of the data suggests that the two types of crystals grew in distinct magmatic environments. Modeling intracrystalline diffusive equilibration between the core and rim of Thalghat crystals led me to obtain a crystal growth rate of 2.03x10-10 cm/s and a residence time of 780 years for the crystals in the magma chamber(s). Employing some assumptions based on field and geochronologic evidence, I extrapolated this residence time to the entire Western Ghats and obtained an estimate of 25,000–35,000 years for the duration of Western Ghats volcanism. This gave an eruptive rate of 30–40 km3/yr, which is much higher than any presently erupting volcano. This result will remain speculative until a similarly detailed analytical-modeling study is performed for the rest of the Western Ghats formations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

To achieve the goal of sustainable development, the building energy system was evaluated from both the first and second law of thermodynamics point of view. The relationship between exergy destruction and sustainable development were discussed at first, followed by the description of the resource abundance model, the life cycle analysis model and the economic investment effectiveness model. By combining the forgoing models, a new sustainable index was proposed. Several green building case studies in U.S. and China were presented. The influences of building function, geographic location, climate pattern, the regional energy structure, and the technology improvement potential of renewable energy in the future were discussed. The building’s envelope, HVAC system, on-site renewable energy system life cycle analysis from energy, exergy, environmental and economic perspective were compared. It was found that climate pattern had a dramatic influence on the life cycle investment effectiveness of the building envelope. The building HVAC system energy performance was much better than its exergy performance. To further increase the exergy efficiency, renewable energy rather than fossil fuel should be used as the primary energy. A building life cycle cost and exergy consumption regression model was set up. The optimal building insulation level could be affected by either cost minimization or exergy consumption minimization approach. The exergy approach would cause better insulation than cost approach. The influence of energy price on the system selection strategy was discussed. Two photovoltaics (PV) systems—stand alone and grid tied system were compared by the life cycle assessment method. The superiority of the latter one was quite obvious. The analysis also showed that during its life span PV technology was less attractive economically because the electricity price in U.S. and China did not fully reflect the environmental burden associated with it. However if future energy price surges and PV system cost reductions were considered, the technology could be very promising for sustainable buildings in the future.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Miami-Dade County implemented a series of water conservation programs, which included rebate/exchange incentives to encourage the use of high efficiency aerators (AR), showerheads (SH), toilets (HET) and clothes washers (HEW), to respond to the environmental sustainability issue in urban areas. This study first used panel data analysis of water consumption to evaluate the performance and actual water savings of individual programs. Integrated water demand model has also been developed for incorporating property’s physical characteristics into the water consumption profiles. Life cycle assessment (with emphasis on end-use stage in water system) of water intense appliances was conducted to determine the environmental impacts brought by each practice. Approximately 6 to 10 % of water has been saved in the first and second year of implementation of high efficiency appliances, and with continuing savings in the third and fourth years. Water savings (gallons per household per day) for water efficiency appliances were observed at 28 (11.1%) for SH, 34.7 (13.3%) for HET, and 39.7 (14.5%) for HEW. Furthermore, the estimated contributions of high efficiency appliances for reducing water demand in the integrated water demand model were between 5 and 19% (highest in the AR program). Results indicated that adoption of more than one type of water efficiency appliance could significantly reduce residential water demand. For the sustainable water management strategies, the appropriate water conservation rate was projected to be 1 to 2 million gallons per day (MGD) through 2030. With 2 MGD of water savings, the estimated per capita water use (GPCD) could be reduced from approximately 140 to 122 GPCD. Additional efforts are needed to reduce the water demand to US EPA’s “Water Sense” conservation levels of 70 GPCD by 2030. Life cycle assessment results showed that environmental impacts (water and energy demands and greenhouse gas emissions) from end-use and demand phases are most significant within the water system, particularly due to water heating (73% for clothes washer and 93% for showerhead). Estimations of optimal lifespan for appliances (8 to 21 years) implied that earlier replacement with efficiency models is encouraged in order to minimize the environmental impacts brought by current practice.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

"Perceptions of Organizational Effectiveness over Organizational Life Cycles" written by Kim S. Cameron and David S. Whetten, posits a theory regarding organizational effectiveness criteria change as firms develop along the life cycle continuum. Induced from observations obtained from a simulation game, the Cameron and Whetten theory is applied in this article to two real organizations, Wendy's and McDonald's, with the intention of demonstrating that this theory is applicable in "real life" situations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

To achieve the goal of sustainable development, the building energy system was evaluated from both the first and second law of thermodynamics point of view. The relationship between exergy destruction and sustainable development were discussed at first, followed by the description of the resource abundance model, the life cycle analysis model and the economic investment effectiveness model. By combining the forgoing models, a new sustainable index was proposed. Several green building case studies in U.S. and China were presented. The influences of building function, geographic location, climate pattern, the regional energy structure, and the technology improvement potential of renewable energy in the future were discussed. The building’s envelope, HVAC system, on-site renewable energy system life cycle analysis from energy, exergy, environmental and economic perspective were compared. It was found that climate pattern had a dramatic influence on the life cycle investment effectiveness of the building envelope. The building HVAC system energy performance was much better than its exergy performance. To further increase the exergy efficiency, renewable energy rather than fossil fuel should be used as the primary energy. A building life cycle cost and exergy consumption regression model was set up. The optimal building insulation level could be affected by either cost minimization or exergy consumption minimization approach. The exergy approach would cause better insulation than cost approach. The influence of energy price on the system selection strategy was discussed. Two photovoltaics (PV) systems – stand alone and grid tied system were compared by the life cycle assessment method. The superiority of the latter one was quite obvious. The analysis also showed that during its life span PV technology was less attractive economically because the electricity price in U.S. and China did not fully reflect the environmental burden associated with it. However if future energy price surges and PV system cost reductions were considered, the technology could be very promising for sustainable buildings in the future.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper establishes the life-cycle dynamics of Corporate Venture Capital (CVC) to explore the information acquisition role of CVC investment in the process of corporate innovation. I exploit an identification strategy that allows me to isolate exogenous shocks to a firm's ability to innovate. Using this strategy, I first find that the CVC life cycle typically begins following a period of deteriorated corporate innovation and increasingly valuable external information, lending support to the hypothesis that firms conduct CVC investment to acquire information and innovation knowledge from startups. Building on this analysis, I show that CVCs acquire information by investing in companies with similar technological focus but have a different knowledge base. Following CVC investment, parent firms internalize the newly acquired knowledge into internal R&D and external acquisition decisions. Human capital renewal, such as hiring inventors who can integrate new innovation knowledge, is integral in this step. The CVC life cycle lasts about four years, terminating as innovation in the parent firm rebounds. These findings shed new light on discussions about firm boundaries, managing innovation, and corporate information choices.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper defines the notion of key inventors — those whose patenting is simultaneously highly productive and also widely cited. By implication, key inventors should be the leaders in any developing new field and we investigate the validity of the notion through an exploration of two emerging technological fields: fuel cell and nanotechnology. The nature of the two groups is compared to discuss the differences between the technological groups.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

South’s Africa’s position as global platinum supplier provides a unique opportunity for an emergent fuel cell industry. The innovative technology’s reliance on platinum has sparked interest in the mining sector, promoting the clean energy-producing devices in their own operations. This research focuses upon contemporary structures of racial oppression within the industry, to analyse how these dynamics influence the development and implementation of innovative technology. It also challenges the sustainability discourse associated with fuel cell technology in South Africa. The study follows a qualitative research approach, incorporating a political ecology focus to highlight the politicized nature of these interactions. The methodology incorporates a literature review, key informant interviews, fieldwork observations and document analysis. Findings indicate that the implementation of fuel cell technology in South Africa’s platinum mines will disproportionately burden historically disadvantaged South Africans, with the lack in technical knowledge-base considered a major challenge. Additionally, it was found that sustainability claims surrounding fuel cell technology are largely based on environmental characteristics. This has resulted in an oversimplification and a depoliticised account of the impacts of the technology. This study looked critically at the convergence of history and innovation, placing emphasis on context, power relations and knowledge to provide a more holistic account of the research problem. Opportunities exist for making a meaningful and viable contribution towards development and sustainability by means of investing in a South African fuel cell industry. The challenge will be in deliberately seeking pathways which address the more complex components of sustainability, benefitting all stakeholders and paying particular attention to the historical, political and social contexts from which the technology emerges. It is this particular context which allows for a questioning and perhaps even a re-evaluation of the sustainability narratives broadly applied to fuel cell technology.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this paper strontium-site-deficient Sr2Fe1.4Co0.1Mo0.5O6-δ-based perovskite oxides (SxFCM) were prepared and evaluated as the cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). All samples exhibited a cubic phase structure and the lattice shrinked with increasing the Sr-deficiency as shown in XRD patterns. XPS results determined that the transition elements (Co/Fe/Mo) in SxFCM oxides were in a mixed valence state, demonstrating the small polaron hopping conductivity mechanism existed. Among the samples, S1.950FCM presented the lowest coefficient of thermal expansion of 15.62 × 10-6 K-1, the highest conductivity value of 28 S cm-1 at 500 °C, and the lowest interfacial polarization resistance of 0.093 Ω cm2 at 800 °C, respectively. Furthermore, an anode-supported single cell with a S1.950FCM cathode was prepared, demonstrating a maximum power density of 1.16 W cm-2 at 800 °C by using wet H2 (3% H2O) as the fuel and ambient air as the oxidant. These results indicate that the introduction of Sr-deficiency can dramatically improve the electrochemical performance of Sr2Fe1.4Co0.1Mo0.5O6-δ, showing great promise as a novel cathode candidate material for IT-SOFCs.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this work Cu1.4Mn1.6O4 (CMO) spinel oxide is prepared and evaluated as a novel cobalt-free cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). Single phase CMO powder with cubic structure is identified using XRD. XPS results confirm that mixed Cu+/Cu2+ and Mn3+/Mn4+ couples exist in the CMO sample, and a maximum conductivity of 78 S cm−1 is achieved at 800 °C. Meanwhile, CMO oxide shows good thermal and chemical compatibility with a 10 mol% Sc2O3 stabilized ZrO2 (ScSZ) electrolyte material. Impedance spectroscopy measurements reveals that CMO exhibits a low polarization resistance of 0.143 Ω cm2 at 800 °C. Furthermore, a Ni-ScSZ/ScSZ/CMO single cell demonstrates a maximum power density of 1076 mW cm−2 at 800 °C under H2 (3% H2O) as the fuel and ambient air as the oxidant. These results indicate that Cu1.4Mn1.6O4 is a superior and promising cathode material for IT-SOFCs.