Abstract: The present disclosure provides a three-phase AC/DC converter aiming for low input current harmonic. The converter includes an input stage for receiving a three-phase AC input voltage, an output stage for at least one load, and one or more switching conversion stages, each stage including a plurality of half bridge modules. The switches in each module operate with a substantially fixed 50% duty cycle and are connected in a specific pattern to couple a DC-link and a neutral node of the input voltage. The AC/DC converter further includes one or more controllers adapted to vary the switching frequency of the switches in the switching conversion stages based on at least one of load voltage, load current, input voltage, and DC-link voltage. The converter can also include one or more decoupling stages, such as, inductive components adapted to decouple the output stage from the switching conversion stages.

Abstract: A system for separating and extracting heavy metals from polluted liquid waste includes a pressurizing unit for pressurizing an extracting solvent using a high-pressure gas, so that the extracting solvent contains supersaturated air and is then jetted into a pneumatic stirring, reacting and separating apparatus, in which the supersaturated air in the extracting solvent instantaneously leaches out to thereby produce a large quantity of micro-sized extracting solvent-bearing bubbles that react with heavy metal-polluted liquid waste contained in the pneumatic stirring, reacting and separating apparatus to separate heavy metals from water. A gas supplying device is connected to and supplies gas to the pneumatic stirring, reacting and separating apparatus to stir the heavy metal-polluted liquid waste. And, a pumping unit is connected to the pneumatic stirring, reacting and separating apparatus to pump out heavy metal-separated water to achieve the object of removing heavy metals from liquid waste.

Abstract: Adsorbent media are prepared by contacting support material with iron containing solutions, followed by drying to coat the support material with iron. Support materials such as sand and olivine are described. The adsorbent material can be used to remove metal contaminants and natural organic matter from water.