983 resultados para Self-sustainable


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This work presents a self-sustainable lighting system using ultracapacitor as a storage device, replacing the conventional battery, using solar energy as the only energy supplier. A detailed study of solar panels, switched mode converters and ultracapacitors was made, in order to design a circuit capable of capturing solar energy and transfer it efficiently to a bank of ultracapacitors. Later, at nighttime, this energy is used for lighting in LED luminaires which have high luminous efficiency and high reliability index. This work presents the design of the solar panel, ultracapacitors bank, the development of the voltage converter circuit and charger working at the maximum power point of the solar panel. All subsystems were simulated and it was shown that the use of ultracapacitors is feasible to feed a LED lamp with enough brightness for a person to walk at night, for two night shifts, using a capacitive bank with twenty-four ultracapacitors. Replacing the battery by an ultracapacitor allows a faster recharge, with low maintenance costs, since ultracapacitors have a lifetime bigger than batteries; beyond reducing the environmental impact, as they don't use potentially toxic chemical compounds

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The research presented in this thesis was developed as part of DIBANET, an EC funded project aiming to develop an energetically self-sustainable process for the production of diesel miscible biofuels (i.e. ethyl levulinate) via acid hydrolysis of selected biomass feedstocks. Three thermal conversion technologies, pyrolysis, gasification and combustion, were evaluated in the present work with the aim of recovering the energy stored in the acid hydrolysis solid residue (AHR). Mainly consisting of lignin and humins, the AHR can contain up to 80% of the energy in the original feedstock. Pyrolysis of AHR proved unsatisfactory, so attention focussed on gasification and combustion with the aim of producing heat and/or power to supply the energy demanded by the ethyl levulinate production process. A thermal processing rig consisting on a Laminar Entrained Flow Reactor (LEFR) equipped with solid and liquid collection and online gas analysis systems was designed and built to explore pyrolysis, gasification and air-blown combustion of AHR. Maximum liquid yield for pyrolysis of AHR was 30wt% with volatile conversion of 80%. Gas yield for AHR gasification was 78wt%, with 8wt% tar yields and conversion of volatiles close to 100%. 90wt% of the AHR was transformed into gas by combustion, with volatile conversions above 90%. 5volO2%-95vol%N2 gasification resulted in a nitrogen diluted, low heating value gas (2MJ/m3). Steam and oxygen-blown gasification of AHR were additionally investigated in a batch gasifier at KTH in Sweden. Steam promoted the formation of hydrogen (25vol%) and methane (14vol%) improving the gas heating value to 10MJ/m3, below the typical for steam gasification due to equipment limitations. Arrhenius kinetic parameters were calculated using data collected with the LEFR to provide reaction rate information for process design and optimisation. Activation energy (EA) and pre-exponential factor (ko in s-1) for pyrolysis (EA=80kJ/mol, lnko=14), gasification (EA=69kJ/mol, lnko=13) and combustion (EA=42kJ/mol, lnko=8) were calculated after linearly fitting the data using the random pore model. Kinetic parameters for pyrolysis and combustion were also determined by dynamic thermogravimetric analysis (TGA), including studies of the original biomass feedstocks for comparison. Results obtained by differential and integral isoconversional methods for activation energy determination were compared. Activation energy calculated by the Vyazovkin method was 103-204kJ/mol for pyrolysis of untreated feedstocks and 185-387kJ/mol for AHRs. Combustion activation energy was 138-163kJ/mol for biomass and 119-158 for AHRs. The non-linear least squares method was used to determine reaction model and pre-exponential factor. Pyrolysis and combustion of biomass were best modelled by a combination of third order reaction and 3 dimensional diffusion models, while AHR decomposed following the third order reaction for pyrolysis and the 3 dimensional diffusion for combustion.

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High street optometric practices are for-profit businesses. They mostly provide sight testing and eye examination services and sell optical products, such as spectacles and contact lenses. The sight testing services are often sold at a vastly reduced price and profits are generated primarily through high margin spectacle sales, in a loss leading strategy. Published literature highlights weaknesses in this strategy as it forms a barrier to widening the scope of services provided within optometric practices. This includes specialist non-refraction based services, such as shared care. In addition this business strategy discourages investment in advanced diagnostic equipment and higher professional qualifications. The aim of this thesis was to develop a greater understanding of the traditional loss-leading strategy. The thesis also aimed to assess the plausibility of alternative business models to support the development of specialist non-refraction services within high street optometric practice. This research was based on a single independent optometric practice that specialises in advanced retinal imaging and offers a broad range of shared care services. Specialist non-refraction based services were found to be poor generators of spectacle sales likely due to patient needs and presenting concerns. Alternative business strategies to support these services included charging more realistic professional fees via cost-based pricing and monthly payment plans. These strategies enabled specialist services to be more self-sustainable with less reliance on cross-subsidy from spectacle sales. Furthermore, improving operational efficiency can increase stand-alone profits for specialist services.Practice managers may be reluctant to increase professional fees due to market pressures and confidence. However, this thesis found that patients were accepting of increased professional fees. Practice managers can implement alternative business models to enhance eye care provision in high street optometric practices. These alternative business models also improve revenues and profits generated via clinical services and improve patient loyalty.

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This deliverable summarizes, validates and explains the purpose and concept behind the RAGE knowledge and innovation management platform as a self-sustainable Ecosystem, supporting innovation processes in the Applied Gaming (AG) industry. The Ecosystem portal will be developed with particular consideration of the demand and requirements of small and medium sized game developing companies, education providers and related stakeholders like AG researchers and AG end-users. The innovation potential of the new platform underlies the following factors: a huge, mostly entire collection of community specific knowledge (e.g., content like media objects, software components and best practices), a structured approach of knowledge access, search and browse, collaboration tools as well as social network analysis tools to foster efficient knowledge creation and transformation processes into marketable technology assets. The deliverable provides an overview of the current status and the remaining work to come, preceding the final version in month 48 of the RAGE project.

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Tese de Doutoramento, Ecologia (Ecologia das Populações), Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

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1994

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The future of the construction industry will require changes at many levels. One is the ability of companies to adapt to new challenges, converting needs to opportunities and simultaneously contributing to the solving of social and environmental problems. In the coming decades we will see a change in attitude in the industry, with a strong tendency to adopt natural and recycled materials, as well as bet on green technology and social innovation oriented to emerging countries. On the other hand, emerging countries have a high demand for housing construction on a large scale, but the current techniques in the developed countries for building requires a large amount of natural resources and skilled labor. This contextualization brings sustainability problems for the construction sector in emerging countries, often with scarce natural resources and with the construction sector underdeveloped. Through a cooperative action between the construction company Mota-Engil Engineering and the University of Minho in Portugal, a construction technology was developed based on the use of Compressed Earth Blocks as part of a social concept for innovative small houses, favoring the adoption of local and natural materials and with the main premise of being dedicated to self-construction. The HiLoTec project - Development of a Sustainable Self-Construction System for Developing Countries was based on this idea. One of the several results of this project is this construction manual. To Mota-Engil the project was a platform for incubation of knowledge about earth construction and to obtain a constructive solution validated technically and scientifically, suitable to be implemented in the markets where it operates. For the University of Minho the project was an opportunity to strengthen skills in research, laboratory and scientific development, through the development of engineering studies, architecture and sustainability, as well as supporting the doctoral scholarships and dissemination of scientific publications. May the knowledge of this project be of benefit, in the future, for the welfare of those who build a HiLoTec house.

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Coastal Regulation Zone (CRZ) notification was issued by the Ministry of Environment and Forest of Government of India in February 1991 as a part of the Environmental Protection Act of 1986 to protect the coast from eroding and to preserve its natural resources. The initial notification did not distinguish the variability and diversity of various coastal states before enforcing it on the various states and Union Territories. Impact assessments were not carried out to assess its impact on socio-economic life of the coastal population. For the very same reason, it was unnoticed or rather ignored till 1994 when the Supreme Court of India made a land mark judgment on the fate of the coastal aquaculture which by then had established as an economically successful industry in many South Indian States. Coastal aquaculture in its modern form was a prohibited activity within CRZ. Lately, only various stakeholders of the coast realized the real impact of the CRZ rules on their property rights andbusiness. To overcome the initial drawbacks several amendments were made in the regulation to suit regional needs. In 1995, another great transformation took place in the State of Kerala as a part of the reorganization of the local self government institutions into a decentralized three tier system called ‘‘Panchayathi Raj System’’. In 1997, the state government also decided to transfer the power with the required budget outlay to the grass root level panchayats (villages) and municipalities to plan and implement the various projects in their localities with the full participation of the local people by constituting Grama Sabhas (Peoples’ Forum). It is called the ‘‘Peoples’ Planning Campaign’’(Peoples’ Participatory Programme—PPP for Local Level Self-Governance). The management of all the resources including the local natural resources was largely decentralized to the level of local communities and villages. Integrated, sustainable coastal zone management has become the concern of the local population. The paper assesses the socio-economic impact of the centrally enforced CRZ and the state sponsored PPP on the coastal community in Kerala and suggests measures to improve the system and living standards of the coastal people within the framework of CRZ.

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This paper is about a design of an urban area Darrieus VAWT, having self-start ability due to an innovative profile design named EN0005, avoiding the need of extra components or external electricity feed-in. An approach is presented to study the ability of a blade profile to offer self-start ability. Methodologies applied for the blade body and for profile development are reported. Field tests and main conclusions are presented to persuade for the arrangement of this design. (C) 2015 Elsevier Ltd. All rights reserved.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

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Since concrete is the most widely utilized construction material, several solutions are currently being developed and investigated for enhancing the sustainability of cementitious materials. One of these solutions is based on producing Recycled Concrete Aggregates (RCA) from existing concrete members resulting by either industrial processes or demolitions of existing structures as a whole. Moreover, waste resulting from industrial processes other than the building construction (i.e., tire recycling, production of steel, powders resulting from other depuration processes) are also being considered as possible low-impact constituents for producing structural concrete and Fiber-Reinforced Cementitious Composites (FRCC). Furthermore, the use of natural fibers is another option for producing environmentally-friendly and cost-effective materials, depending on the local availability of raw materials. To promote the use of concretes partially composed of recycled constituents, their influence on the mechanical and durability performance of these concretes have to be deeply investigated and correlated. This was the main goal of the EnCoRe Project (www.encore-fp7.unisa.it), a EU-funded initiative, whose activities and main findings are summarized in this paper.

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Extant research on exchange-listed firms has acknowledged that the concentration of ownership and the identity of owners make a difference. In addition, studies indicate that firms with a dominant owner outperform firms with dispersed ownership. During the last few years, scholars have identified one group of owners, in particular, whose ownership stake in publicly listed firm is positively related to performance: the business family. While acknowledging that family firms represent a unique organizational form, scholars have identified various concepts and theories in order to understand how the family influences organizational processes and firm performance. Despite multitude of research, scholars have not been able to present clear results on how firm performance is actually impacted by the family. In other words, studies comparing the performance of listed family and other types of firms have remained descriptive in nature since they lack empirical data and confirmation from the family business representatives. What seems to be missing is a convincing theory that links the involvement and behavioral consequences. Accordingly, scholars have not yet come to a mutual understanding of what precisely constitutes a family business. The variety of different definitions and theories has made comparability of different results difficult for instance. These two issues have hampered the development of a rigorous theory of family business. The overall objective of this study is to describe and understand how the family as a dominant owner can enhance firm performance, and can act a source of sustainable success in listed companies. In more detail, in order to develop understanding of the unique factors that can act as competitive advantages for listed family firms, this study is based on a qualitative approach and aims at theory development, not theory verification. The data in this study consist of 16 thematic interviews with CEOs, members of the board, supervisory board chairs, and founders of Finnish listed-family firms. The study consists of two parts. The first part introduces the research topic, research paradigm, methods, and publications, and also discusses the overall outcomes and contributions of the publications. The second part consists of four publications that address the research questions from different viewpoints. The analyses of this study indicate that family ownership in listed companies represents a structure that differs from the traditional views of agency and stewardship, as well as from resource-based and stakeholder views. As opposed to these theories and shareholder capitalism which consider humans as individualistic, opportunistic, and self-serving, and assume that the behaviors of an investor are based on the incentives and motivations to maximize private profits, the family owners form a collective social unit that is motivated to act together toward their mutual purpose or benefit. In addition, socio-emotional and psychological elements of ownership define the family members as owners, rather than the legal and financial dimensions of ownership. That is, collective psychological ownership of family over the business (F-CPO) can be seen as a construct that comprehensively captures the fusion between the family and the business. Moreover, it captures the realized, rather than merely potential, family influence on and interaction with the business, and thereby brings more theoretical clarity of the nature of the fusion between the family and the business, and offers a solution to the problem of family business definition. This doctoral dissertation provides academics, policy-makers, family business practitioners, and the society at large with many implications considering family and business relationships.

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The large-scale production of clean energy is one of the major challenges society is currently facing. Molecular hydrogen is envisaged as a key green fuel for the future, but it becomes a sustainable alternative for classical fuels only if it is also produced in a clean fashion. Here, we report a supramolecular biomimetic approach to form a catalyst that produces molecular hydrogen using light as the energy source. It is composed of an assembly of chromophores to a bis(thiolate)-bridged diiron ([2Fe2S]) based hydrogenase catalyst. The supramolecular building block approach introduced in this article enabled the easy formation of a series of complexes, which are all thoroughly characterized, revealing that the photoactivity of the catalyst assembly strongly depends on its nature. The active species, formed from different complexes, appears to be the [Fe-2(mu-pdt)(CO)(4){PPh2(4-py)}(2)] (3) with 2 different types of porphyrins (5a and 5b) coordinated to it. The modular supramolecular approach was important in this study as with a limited number of building blocks several different complexes were generated.

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Due to the changing nature of the facilities management (FM) profession, facilities managers are increasingly engaged with the evolving sustainability agenda in the UK and the development or uptake of sustainability policies within their organisations. This study investigates how facilities managers are engaging with the sustainability agenda and the drivers, policy issues and information they use to improve their sustainability performance management. A web based self-administered questionnaire survey of facilities managers in the UK was conducted to identify drivers and issues that influence and support good sustainable practices. A total of 268 facilities managers responded. The results indicate that legislation is the most important driver for the implementation of sustainable practices. Corporate image and Organisational ethos are also recognised. However demand for efficient monitoring, management and reporting on environmental impact is not highly rated even though the top three issues of sustainability managed by facilities managers are energy management, waste and recycling management and carbon footprint. In addition, facilities managers are expected to take ownership of activities assigned to the reduction of carbon emission. Government industries and organisation with high turnover are more likely to have a sustainability policy. Financial constraints are the main barriers while legislations are the main driver for implementing sustainability. For non-profit organisations and the charitable sector, financial constraints are no hindrance to implementing a sustainability policy. The conclusion drawn is that sustainability agendas continue to be influenced by regulated environmental issues rather than a balanced approach which takes into consideration the wider social and economic aspects of sustainability. While this scenario is far from ideal, the expectation is that the organisation will trust FM to take a vital role in delivering a comprehensive sustainability policy due to the rising tide of legislation, public scrutiny, as well as the needed business case for genuinely embracing sustainability. However, as the integration of sustainability with core business strategies is continuously evolving the emphasis on different drivers will vary from organisation to organisation as well as the responsibilities of facilities managers.

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The present study is focused on the analysis of the political, economical and social factors that may interfere with the possibility of a Green Revolution as a solution for Mozambique to reach self-sufficiency and to reduce poverty. In order to perform such analysis, the study analyzes the consequences of the decolonization process in Mozambique focusing that the independence process in Mozambique did not create non-colonial models for the Agriculture Sector. Later on, the study tries to understand the impact of HIV/AIDS and Malaria on the labor force. By then, it explores the concepts of the Green Revolution and its successful history in India. At the end, it tries to evaluate if a Green Revolution is possible in Africa, especially in Mozambique, first identifying the factors, which characterized the Green Revolution in India, and trying to link those factors with the reality of Mozambique. The report is structured as followed; Chapter 2, ¿The decolonization process and its impacts on the agriculture sector¿. It gives information about the decolonization process, and explores its consequences. Chapter 3, ¿The Impacts of HIV/AIDS and Malaria on the Labor Force¿. It analyzes the impact of those diseases in the labor force. Chapter 4 ¿The Green Revolution and the Agriculture Sector¿, explores the concepts of Green Revolution, its success in India and its history in Mozambique. Chapter 5, finally, centers on conclusions, findings and recommendations.