A novel high step-up DC-DC converter with coupled-inductor and switched-capacitor techniques is proposed in this paper. The capacitors are charged in parallel and are discharged in series by the coupled inductor, stacking on the output capacitor. Thus, the proposed converter can achieve high step-up voltage gain with appropriate duty ratio. Besides, the voltage spike on the main switch can be c...

This paper proposes dynamic clustering for coverage-time maximization (DC-CTM) in sensor networks. The coverage-time is defined as the time until one of cluster heads (CHs) runs out of energy in clustering-based sensor networks. DC-CTM regulates cluster radii for balanced energy consumption among CHs for coverage-time maximization. By using DC-CTM, three advantages can be achieved. The first on...

This paper presents an off-line integrated full ballast to supply a 35 W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (a buck converter) into a single switch power stage, operating with peak current control. As it will be shown, this control scheme maintains the current through the load constant, ...

Clay fractions in soils from a transect of the Mazama ash deposit (6600-yr-old) contained more than 80% amorphous material. Instrumental neutron activation analysis was used to compare the trace element composition of the soil clay with the unweathered volcanic glass. The clay fractions had only 10% as much Na as the volcanic glass. Conversely, the rare earth element concentrations were about t...

The clay and non-clay minerals have been identified by XRD analysis. The non-clay minerals include quartz, crystobalite, orthoclase, microcline, plagioclase, calcite, siderite and dolomite, and the clay minerals include kaolinite (52.39%), illite (36.39%) and illite-smectite mixed layer minerals (11.21%). Kaolinite is the most dominant component in the clay mineral assemblages. The clay mineral...

High density polyethylene (HDPE)/bamboo composites with different nanoclay and maleated polyethylene (MAPE) contents were fabricated by melt compounding. The compounding characteristics, clay dispersion, HDPE crystallization, and mechanical properties of the composites were studied. The equilibrium torque during compounding decreased with use of clay masterbatch and increased with the addition ...

Column experiments were conducted to study chemical factors that influence the release of clay (kaolinite and quartz minerals) from saturated Ottawa sand of different sizes (710,360, and 240 microm). A relatively minor enhancement of clay release occurred when the pH was increased (5.8 to 10) or the ionic strength (IS) was decreased to deionized (DI) water. In contrast, clay release was dramati...

19 Clay-polymer composites were designed for use in filtration processes for disinfection 20 during the course of water purification. The composites were formed by sorption of 21 polymers based on starch modified with quaternary ammonium ethers onto the 22 negatively charged clay mineral bentonite. The performance of the clay-polymer 23 complexes in removal of bacteria was strongly dependent on...

OBJECTIVE The aim of this study was to investigate the effect of aluminosilicate clay nanotubes (Halloysite, HNT) incorporated into the adhesive resin of a commercially available three-step etch and rinse bonding system (Adper Scotchbond Multi-Purpose/SBMP) on dentin bond strength, as well as the effect on several key physicochemical properties of the modified adhesive. METHODS Experimental a...

Soil erosion is a crucial problem in Nepal where more than 80% of the land area is mountainous and still tectonically active. Although deforestation, overgrazing and intensive agriculture, due to population pressure, have caused accelerated erosion, natural phenomena inducing erosion, such as exceptional rains, earthquakes and glacial-lake-outburst flooding in the high Himalayas are also common...