9,732 research outputs found
Can Polymer Solar Cells Open the Path to Sustainable and Efficient Photovoltaic Windows Fabrication?
Sunlight is among the most abundant energy sources available on our planet. Finding adequate solutions to properly and efficiently harvest it is of major importance to potentially solve the global energy crisis. Polymer solar cells have been introduced in the late 20th century as low‐cost and easily processed alternative to the state‐of‐the‐art silicon photovoltaics. Their power conversion efficiencies, which were initially rather low, are constantly improving and now reach values close to 15 %. As their optical properties can be easily tuned, designing active layer which absorb homogeneously throughout the visible spectrum is relatively simple. These peculiar characteristics enable the possibility to fabricate visibly transparent solar cells with high color rendering indices which can be employed as photovoltaic windows. After reviewing some of the most successful examples of polymer solar cell‐based transparent photovoltaic window fabrication, I will discuss the possibility to produce these devices in a sustainable and/or eco‐friendly manner while maintaining their performances
Chinese Wall Security Policy
This project establishes a Chinese wall security policy model in the environment of cloud computing. In 1988 Brewer and Nash proposed a very nice commercial security policy in British financial world. Though the policy was well accepted, but the model was incorrect. A decade later, Dr. Lin provided a model in 2003 that meets Brewer & Nash’s Policy. One of the important components in Cloud computing is data center. In order for any company to store data in the center, a trustable security policy model is a must; Chinese wall security policy model will provide this assurance. The heart of the Chinese Wall Security Policy Model is the concept of Conflict of Interest (COI). The concept can be modeled by an anti-reflexive, symmetric and transitive binary relation. In this project, by extending Dr. Lin’s Model, we explore the security issues in the environment of cloud computing and develop a small system of the Chinese Wall Security Model
Combating Climate Change in the Capital of Car Culture: Part 1
Say the words "Los Angeles," and you might conjure visions of epic traffic jams, air pollution so thick you can't see the hills, and a city that seems designed to intimidate and marginalize pedestrians and bicyclists.But a new reality is emerging in the city of angels. A slew of developments over the past decade is helping the world capital of car culture transform itself into a world leader in sustainable transportation. While traffic is still bad, the air is significantly cleaner, and public transit alternatives are expanding.If the trends continue, L.A.'s transportation sector could become a model for California -- and the nation -- as we struggle to end our dependence on oil
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