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Microwave heating is a developing noncontact heating method in dewatering technology. It has been proved to be effective to dewater high moisture content in mineral substance via the application of the dielectric loss of materials. In this study, the effects of microwave power levels (250–550 W) and different sample masses (20–40 g) on microwave drying behavior of pyrolusite have been investigated. For the purpose of the mechanism and morphological changes to the pyrolusite in the process of drying, thermogravimetric analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were used, respectively. The experiment results demonstrated that an increase in the microwave power as well as sample mass was found to increase the drying rate during pyrolusite drying processes, with there are four main mass loss stages from 20 to 900 °C. The SEM-EDS analysis results show that morphological changes with the presence of more pores and appearance in spiral cross-linking way reduced the particle size and the shrinkage of the faces and edges, in which it can been concluded that the microwave drying is an effective method to produce the high-grade pyrolusite. By analysis, the increased pore structure and shrinkage phenomena can be observed, which increase the specific surface area of manganese ore effectively and may benefit the subsequent reduction process of high valence manganese, after the process of microwave heating. [ABSTRACT FROM AUTHOR]

More than 900 million people worldwide live in slums. These slums mainly can be found in cities of the global south and are characterized by poor living conditions and usually insufficient access to basic infrastructure such as water or energy. In order to improve the living conditions of slum inhabitants, information about the number, location and size of the slums is required to plan supply infrastructure. We therefore identify morphological slums in eight different cities in Africa, South America and Asia, using remote sensing data and analyse their size distributions. We show that 84.6% of all observed morphological slums have a size between 0.001 and 0.1 km2. These results rely on a consistent approach using a clear ontology and conceptual frame for classification. However, classification methods for these underserved areas differ. We show slum classifications based on different methods reveal a strong dependency between the particular method and the resulting size distribution. The study shows the relevance of remote sensing for the investigation of slums and the results can be used for infrastructure planning, as infrastructure improvement projects are often limited to the large known slums. Whereas, the large number of small slums distributed across the city is often neglected. [ABSTRACT FROM AUTHOR]

The use of high-pressure grinding rolls (HPGR) prior to ball mills has become a common practice in cement clinker grinding due to significant energy savings in comparison to ball milling alone. The energy savings has been attributed to higher energy efficiency of HPGR at low reduction ratios, smaller particle top sizes in the ball mill feed, and the weakening of particles resulting from compression of particle bed by HPGR. This study attempts to show how the weakening effect changes the kinetic breakage parameters of the HPGR-treated clinker. For this purpose, batch ball mill experiments were conducted with three narrow-size fractions (−3.35 + 2.36, −1.70 + 1.18, and −0.85 + 0.60 mm) of the feed and product samples of an industrial HPGR, and the breakage rate and breakage distribution parameters of the samples were compared. The results show that the weakening effect leads to nonlinear breakage rates for all sizes, coupled with abnormal breakage at the two coarsest sizes. The weakening effect leads to increased breakage rates of the HPGR product relative to particles of the HPGR feed. The increased breakage rates are accompanied by coarser progeny distributions for the two coarsest size ranges relative to that of the HPGR feed. The progeny distribution of the finest size of the HPGR product, however, is finer than that of the HPGR feed. Ball milling of size-distributed feeds prepared from the HPGR product and feed samples for the same grinding time produces self-similar size distributions when the size is normalized with respect to the median size. [ABSTRACT FROM PUBLISHER]

This study focuses on particulate-bound Hg (Hg[p]) composition (ng/g) (defined as ng/g), concentrations (ng/m3) and dry deposition (ng/m2*min) variations for PM18, PM10, PM2.5, and PM1.0. Three characteristic sampling sites collected 1-day ambient suspended particles during November and December 2010 using MOUDI-100S4 samplers. Additionally, Hg(p) size distributions are also characterized. Composition variations of Hg(p) in PM18 were in the order of 0.158 ± 0.055 ng/g (Quan-xing sampling site) > 0.086 ± 0.097 ng/g (Hung-kuang sampling site) > 0.083 ± 0.065 ng/g (Gao-mei sampling site). Further, composition variations of Hg(p) in PM10 were in the order of 0.115 ± 0.038 ng/g (Quan-xing site) > 0.107 ± 0.080 ng/g (Gao-mei site) > 0.103 ± 0.060 ng/g (Hung-kuang site). Composition variations of Hg(p) in PM2.5 were in the order of 0.885 ± 0.423 ng/g (Quan-xing site) > 0.458 ± 0.105 ng/g (Gao-mei site) > 0.372 ± 0.157 ng/g (Hung-kuang site). Finally, composition variations of Hg(p) in PM1.0 were in the order of 0.913 ± 0.441 ng/g (Quan-xing site) > 0.698 ± 0.293 ng/g (Hung-kuang site) > 0.508 ± 0.270 ng/g (Gao-mei site). The Hg(p) size distribution peaked at 1.0 μm at the Quan-xin site, and the lowest average Hg(p) size distribution was 18 μm at the Hung-kung site. The main possible sources for atmospheric particulate-bound mercury Hg(p) were likely from transportation, chemical plant and fossil fuel combustion (Fang et al., 2011). In addition to the above findings, other possible nearby sources at Taichung Thermal Power Plant (TTPP) and Central Taiwan Science Park (CTSP) were: steel industry, electronic industry, plastic industry, chemical industry, basic metal manufacturing, machinery manufacturing, coal products and petroleum. Our sampling sites were in the regions of all of the above sources. [ABSTRACT FROM AUTHOR]

Electric ink display is one of the prospect technologies in paper-like display. In this paper, electric ink microcapsules are prepared by means of an in situ polymerization and complex coacervation. In order to obtain the microcapsules in a uniform size distribution, this study focused on the inter-facial tension between tetrachloroethylene and water solution, the dispersion of the core droplets and the microencapsulation with different kind of surfactants. By measuring the inter-facial tensions between water and tetrachloroethylene, it is found that urea-formaldehyde (UF) pre-polymer presents certain surface activity due to the inter-facial tension descending from 43?mN?m -1 to 35?mN?m -1 . Because the surface activity of pre-polymer is not valid, the water-soluble emulsifiers can occupy on the surface of the droplets and prevent the UF resin depositing there. The analysis of the size distribution shows that the UF microcapsules are multi-dispersed. Furthermore, the influence of anionic surfactant of SDS on the size distribution of the core droplets is also investigated. The average diameters of the core droplets prepared with 0.005?wt% and 0.012?wt% SDS are?~50?µm and 28?µm, respectively. That reveals the existence of SDS not only decreases the droplet diameters, but also makes the size distribution centralized. Because the surface of the core droplets is charged due to the absorption of SDS anionic, the Gelatin and Gum Arabic (GA) coacervating layer is easy to form there. The size of the GA microcapsules prepared with 0.003?wt% SDS is?~65?µm. Finally; the responsive behaviour of the microcapsules to electric field is also investigated. [ABSTRACT FROM AUTHOR]