Constitution of the Ni3Cr-Ni3Al-Ni3W system

Isothermal sections of the Ni-Cr-Al-W system have been investigated at 75 at % Ni and temperatures of 1523 and 1273 K, by means of phase compositional analysis, X-ray diffraction and microscopical examination. The alloys studied lay in the range 2.5 to 10 at % Cr, 12.5 to 20 at% Al, 2.5 to 6.25 at % W, The phases formed were, and the bcc solid solution based on tungsten (designated ₂). The maximum extent of the region was found to be 3 at % each of chromium and tungsten. Preferential partitioning of tungsten to occurred. Study of an Ni-10Cr-12.5Al-2.5W alloy aged at 1273 and 1073 K, after quenching from 1573 K, showed that changes in and compositions and lattice parameters occur as a function of ageing time.     

Bed collapse dynamics of fluidized beds of nano-powder

Bed collapse experiments have been carried out in fluidized beds of agglomerated nano-powders possessing high void fractions. Transient responses for the local pressure-drop as well as the gas velocity during the collapse were recorded. From the local pressure transient data, occurrences of key events of the collapse dynamics were identified. The first event is the zero pressure-drop condition soon after the flow interruption while the second is the global minimum on the pressure-drop profile that marks the end of the first stage of the bed collapse characterized by fast bed transients. The second stage is a relatively slow process, which ends with the onset of the zero pressure-drop condition again (third event) that reflects particles becoming stationary, thus signaling the completion of the collapse dynamics. The time of the first stage of the collapse is found to vary linearly with the initial fluidization velocity at which the collapse experiment was initiated whereas the total collapse time shows a rather weak dependence on the fluidization velocity. On the other hand, the velocity transients during the collapse follow first-order time lag that can be accurately modeled using a single time constant irrespective of the initial fluidization velocity.     

An energy-efficient cuckoo search algorithm for virtual machine placement in cloud computing data centers

The Journal of Supercomputing - The advent of virtualization technology has created a huge potential application for cloud computing. In virtualization, a large hardware resource is often broken...     

User-centric hybrid semi-autoencoder recommendation system

Recommendation System is one of such solutions to overcome information overload issues and to identify products most relevant to users and provide suggestions to users for items they might be interested in consuming or elements matching their needs. The significant challenge of several recommendation approaches is that they suggested a huge number of things to the target user. But the exciting items, according to the target user, are seen at the bottom of the recommended list. The proposed approach has improved the quality of recommendations by implementing some of the unique features in the new framework of auto encoder called semi-autoencoder, which contains the rating information as well as some additional information of users. Autoencoder is widely used in the recommender system because it gives the best result for feature extraction, dimensionality reduction, regeneration of data, and a better understanding of the user’s characteristics. The experimental results are compared with some established popular methods using precision, recall, and F-measure evaluation measures. Users generally don’t want to see lots of suggestions. With its six building blocks, the proposed approach gives better performance for the top 10 recommendations compared to other well-known methods.

     

A health-based life cycle impact assessment (LCIA) for cement manufacturing: a comparative study of China and Canada

Life cycle impact assessment methodology was applied to the cement manufacturing sectors in China and Canada for comparative purposes. Primary air emissions of NO _x , SO₂, PM, and CO were evaluated in terms of intensity per tonne of Portland cement and in respect of their contribution to winter smog. The Eco-Indicator 99 impact category for respiratory effects on humans caused by inorganic substances was used as surrogate for winter smog. Impact was assessed in disability-adjusted life years (DALYs), and damage, normalization, and weighting factors followed the egalitarian perspective. Results indicate some ambiguity for emission intensities with China outperforming Canada in NO _x and SO₂ while underperforming in PM and CO. However, in terms of impact to human health, China was more than double that of Canada at 14.2 DALYs per tonne of Portland cement. Highlighted by energy-intensive and trade-exposed industry like cement, environmental performance, and emissions leakage (associated with offshoring production) can have serious ramifications on regional air quality. Modernization and innovation in combination with a strong regulatory framework needs to be implemented in both emerging markets and developed markets to minimize emissions leakage and pollution loading.     

Water use in unconventional oil and gas development: an assessment on water use metric evaluation and selection

This study identifies five data input categories essential to quantifying water use and the environmental impacts via water use metrics (i.e., Water Footprints) when evaluating water use during upstream unconventional oil and gas. Published water use metrics, which included provisions for addressing each of the five categories, were selected for evaluation. The selected metrics were compared and evaluated against data parameters defined within each of the input categories. Finally, a decision tree for method selection, which differentiates between assessment mechanisms, impact indicator, and result units, is presented to facilitate method selection of future studies of water use in unconventional oil and gas development.