3,170 research outputs found

    The Path towards 1.5 degrees Celsius. CEPS Policy Brief No. 336, 3 December 2015

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    In less than one year, the country-led exercise in preparing Intended Nationally Determined Contributions (INDCs) has accomplished what the top-down approach characteristic of the UNFCCC has not been able to achieve in over 21 years of negotiations, namely to produce a sound agreement to reduce climate change. As such, the UNFCCC should adopt a new process similar to that used in developing the INDCs, in which Parties to the Convention would mobilise their national efforts, but on a wider scale and under certain agreed binding conditions. To ensure a comprehensive engagement, this Policy Brief recommends the introduction of a four-tier system in which the most developed nations called upon to take the lead, but with the very least developed nations also contributing to the intended UN objective

    An overview of cloud services adoption challenges in higher education institutions

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    Information Technology (IT) plays an important role in enabling education services be delivered to users. Most education online services in universities have been run on the cloud to provide services to support students, lecturers, researchers and administration staff. These are enabled with the emergence of cloud computing in the world of IT. Cloud computing offers on demand Internet-based computing services. This paper presents an overview of cloud computing adoption in higher education, mainly tertiary institutions and universities. The focus of the paper is the challenges of cloud computing in higher education. It introduces the background to cloud computing and reviews research on adoption challenges in higher education institutions. These challenges are important as they provide an overview of the adoption of cloud in higher education. The authors proposed an integrated reference model based on the challenges in the literature integrated with TAM model to investigate the factors influence the users’ attitudes and behaviors toward using cloud education services in universities ICT provision

    Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

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    We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems

    Iron ochre: a pre-catalyst for the cracking of methane

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    Background: Iron ochres are gelatinous sludges which can cause problems in terms of water management. In this manuscript, the application of iron ochre obtained from a river has been applied to catalytically crack methane – another potential waste product - into two useful products, hydrogen and a magnetic carbon containing composite.<p></p> Results: The powder XRD pattern of the iron ochre was found to be consistent with the expected 2-line ferrihydrite and EDX analysis showed Fe to be a major component although some Si was present. The sample was observed to contain a fraction with a tubular morphology consistent with the presence of extra-cellular biogenic iron oxide formed by leptothrix. Upon exposure to methane at elevated temperatures, the material was found to transform into an active catalyst for hydrogen production yielding a magnetic carbon containing composite material comprising filamentous carbon and encapsulating graphite.<p></p> Conclusion: The application of two waste products – iron ochre and methane – to generate two useful products – hydrogen and a magnetic carbon containing composite- has been demonstrated. Furthermore, the ochre has been shown to comprise tubular morphology extra-cellular biogenic iron oxide which may be of interest in terms of other applications.<p></p&gt

    Security risk factors that influence cloud computing adoption in Saudi Arabia government agencies

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    Cloud computing technologies play a substantial role in public organizations and private sector companies since it reduces the cost of using information technology services and allows users to access the service anytime and everywhere, whilst only paying for what they use. In developing countries, such as Saudi Arabia, the cloud computing is still not widely adopted, compared to countries in the west. In order to promote the adoption of cloud computing, it is important to recognize that an important and specific issue related to cloud computing is the potential and perceived security risks posed by implementing such technology. Therefore, the aim of this research is to investigate the security risk factors that influence organization to adopt cloud computing in a Saudi Arabia context. This research proposed a framework for the successful adoption of cloud computing, focused on risks when implementing security in the cloud system

    Determination of the yield loci of four sheet materials (AA6111-T4, AC600, DX54D+Z, and H220BD+Z) by using uniaxial tensile and hydraulic bulge tests)

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    In sheet metal forming simulation, a flow curve and a yield criterion are vital requirements for obtaining reliable numerical results. It is more appropriate to determine a flow curve by using biaxial stress condition tests, such as the hydraulic bulge test, than a uniaxial test because hardening proceeds higher strains before necking occurs. In a uniaxial test, higher strains are extrapolated, which might lead to incorrect results. The bulge test, coupled with the digital image correlation (DIC) system, is used to obtain stress–strain data. In the absence of the DIC system, analytical methods are used to estimate hardening. Typically, such models incorporate a correction factor to achieve correlation to experimental data. An example is the Chakrabarty and Alexander method, which uses a correction factor based on the n value. Here, the Chakrabarty and Alexander approach was modified using a correction factor based on normal anisotropy. When compared with DIC data, the modified model was found to be able to better predict the hardening curves for the materials examined in this study. Because a biaxial flow curve is required to compute the biaxial yield stress, which is an essential input to advanced yield functions, the effects of the various approaches used to determine the biaxial stress–strain data on the shape of the BBC2005 yield loci were also investigated. The proposed method can accurately predict the magnitude of the biaxial yield stress, when compared with DIC data, for all materials investigated in this study

    Power Consumption and Energy Estimation in Smartphones

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    A developer needs to evaluate software performance metrics such as power consumption at an early stage of design phase to make a device or a software efficient especially in real-time embedded systems. Constructing performance models and evaluation techniques of a given system requires a significant effort. This paper presents a framework to bridge between a Functional Modeling Approach such as FSM, UML etc. and an Analytical (Mathematical) Modeling Approach such as Hierarchical Performance Modeling (HPM) as a technique to find the expected average power consumption for different layers of abstractions. A Hierarchical Generic FSM “HGFSM” is developed to be used in order to estimate the expected average power. A case study is presented to illustrate the concepts of how the framework is used to estimate the average power and energy produced
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