Numerical investigation of large-scale seasonal rock-pit energy storage system

A twodimensional axisymmetric model, which is computationally inexpensive, has been proposed to predict the property changes that occur in a seasonal rock-pit energy storage (RPES) system. The geometry of the rock-pit has been simplified into a shape that can be extended for any seasonal storage system with a three-dimensional conical geometry. The computational domain has been solved using both linear thermal equilibrium (LTE) and linear thermal non-equilibrium (LTNE) models, and the former has been found to be computationally quick and accurate. The model has predicted a 95% energy saving at the highest flow conditions required in the mine. Further analysis has suggested that the increase in storage capacity by decreasing the porosity of rocks in the rock-pit is insignificant compared to the corresponding increase in fan power. Furthermore, the investigation done on natural rocks has indicated an increased ability to store heat in the rock-pit when rocks with higher thermal mass have been used. The use of RPES has shown a significant potential to reduce the carbon footprint. Finally, an economic analysis done on the system has shown a return on investment of just under 12 years.     

Intense UV-light absorption of ZnO nanoparticles prepared using a pulse combustion-spray pyrolysis method

We report the synthesis and characterization of ZnO nanoparticles prepared via pulse combustion-spray pyrolysis (PC-SP) at a high rate. Instead of using an ultrasonic nebulizer as the atomizer during PC-SP synthesis, a two-fluid nozzle was used to enhance the production rate. A high production rate was achieved by the use of a two-fluid nozzle, which efficiently generated droplets in large quantities, and by controlling the rate of precursor flow. ZnO nanoparticles were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectroscopy. The prepared ZnO nanoparticles were spherical and highly crystalline with an average size of 15.6 nm. In addition, high UV-light absorption and visible-light transparency properties were successfully obtained for a dispersion of ZnO nanoparticles in glycerol. The high UV-blocking capacity of the ZnO particle dispersion makes the dispersion potentially useful in cosmetic applications.     

GPU Accelerated Direct Volume Rendering on an Interactive Light Field Display

We present a GPU accelerated volume ray casting system interactively driving a multi‐user light field display. The display, driven by a single programmable GPU, is based on a specially arranged array of projectors and a holographic screen and provides full horizontal parallax. The characteristics of the display are exploited to develop a specialized volume rendering technique able to provide multiple freely moving naked‐eye viewers the illusion of seeing and manipulating virtual volumetric objects floating in the display workspace. In our approach, a GPU ray‐caster follows rays generated by a multiple‐center‐of‐projection technique while sampling pre‐filtered versions of the dataset at resolutions that match the varying spatial accuracy of the display. The method achieves interactive performance and provides rapid visual understanding of complex volumetric data sets even when using depth oblivious compositing techniques.     

Ontology extraction from relational database: Concept hierarchy as background knowledge

Relational Database (RDB) has been widely used as the back-end database of information system. Contains a wealth of high-quality information, RDB provides conceptual model and metadata needed in the ontology construction. However, most of the existing ontology building approaches convert RDB schema without considering the knowledge resided in the database. This paper proposed the approach for ontology extraction on top of RDB by incorporating concept hierarchy as background knowledge. Incorporating the background knowledge in the building process of Web Ontology Language (OWL) ontology gives two main advantages: (1) accelerate the building process, thereby minimizing the conversion cost; (2) background knowledge guides the extraction of knowledge resided in database. The experimental simulation using a gold standard shows that the Taxonomic F-measure (TF) evaluation reaches 90% while Relation Overlap (RO) is 83.33%. In term of processing time, this approach is more efficient than the current approaches. In addition, our approach can be applied in any of the fields such as eGoverment, eCommerce and so on.     

Realizing super-long Cu2O nanowires arrays for high-efficient water splitting applications with a convenient approach

Nanowire (NW) structures is an alternative candidate for constructing the next generation photoelectrochemical water splitting system, due to the outstanding optical and electrical properties. NW photoelectrodes comparing to traditional semiconductor photoelectrodes shows the comparatively shorter transfer distance of photo-induced carriers and the increase amount of the surface reaction sites, which is beneficial for lowering the recombination probability of charge carriers and improving their photoelectrochemical (PEC) performances. Here, we demonstrate for the first time that super-long Cu₂O NWs, more than 4.5 μm, with highly efficient water splitting performance, were synthesized using a cost-effective anodic alumina oxide (AAO) template method. In comparison with the photocathode with planar Cu₂O films, the photocathode with Cu₂O NWs demonstrates a significant enhancement in photocurrent, from –1.00 to –2.75 mA/cm² at –0.8 V versus Ag/AgCl. After optimization of the photoelectrochemical electrode through depositing Pt NPs with atomic layer deposition (ALD) technology on the Cu₂O NWs, the plateau of photocurrent has been enlarged to –7 mA/cm² with the external quantum yield up to 34% at 410 nm. This study suggests that the photoelectrode based on Cu₂O NWs is a hopeful system for establishing high-efficiency water splitting system under visible light.     

Controlled arrangement of nanoparticle arrays in block-copolymer domains

This Review describes recent results on the precise spatial distribution control of metal and semiconductor nanoparticles into domains of microphase-separated block copolymers. Specific focus is directed towards selective incorporation into a specific microphase of a block copolymer. Details on theoretical aspects concerning nanoparticle incorporation as well as practical examples are given. Furthermore, examples on applications and technological aspects of the resulting nanoparticle/polymer nanocomposites are provided.     

Wind energy for rural areas of Algeria

This paper presents long-term analysis of wind speed data in terms of annual, seasonal and diurnal variations at Tindouf, which is situated on the south west region of Algeria. The wind speed data was collected over a period of 08 years between 1976 and 1984. The study showed that the long-term seasonal wind speeds were found to be relatively higher during September compared to other months. The diurnal change in long-term mean wind speed indicated that higher electricity could be produced during 09:00–18:00 h, which also coincides with higher electricity demand period. The annual wind energy production and capacity factor, obtained using wind speed frequency distribution and wind power curve of 1000 kW wind turbine and RETScreen software were found comparable with each other if unadjusted energy production values calculated by the software were used rather than the renewable energy delivered. Development of wind farm of 30 MW installed capacity at this site could result into avoidance of 23,252 tonnes/year of CO₂ equivalents GHG from entering into the local atmosphere thus creating a clean and healthy atmosphere for local inhabitants.     

Database optimization for novelty mining of business blogs

The widespread growth of business blogs has created opportunities for companies as channels of marketing, communication, customer feedback, and mass opinion measurement. However, many blogs often contain similar information and the sheer volume of available information really challenges the ability of organizations to act quickly in today’s business environment. Thus, novelty mining can help to single out novel information out of a massive set of text documents. This paper explores the feasibility and performance of novelty mining and database optimization of business blogs, which have not been studied before. The results show that our novelty mining system can detect novelty in our dataset of business blogs with very high accuracy, and that database optimization can significantly improve the performance.