Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

Disclosed are devices, systems, apparatuses, methods, products, and other implementations of vapor pressure solids. In some embodiments, a vapor pressure solid may include a one- or multi-component matrix material. In some embodiments, the multi-components matrix material is a two-part PDMS comprising a first and second matrix material. The first matrix material is capable of being mixed with one or more vaporizable fluids that causes the first matrix material to swell. The second matrix material is capable of being mixed with the swelled first matrix material to produce an actuating material. When the actuating material is heated, the one or more vaporizable fluids expand, resulting in vapors. The increased pressure applied by the vapors causes the actuating material to expand.

An electrochemical heat transfer device for a hot water tank utilizes an electrochemical hydrogen compressor to pump hydrogen into and out of a tank having a metal hydride forming alloy therein. The absorption of hydrogen by the metal hydride forming alloy is exothermic, produces heat, and the desorption of the hydrogen from the metal hydride forming alloy is endothermic and draws heat in. An electrochemical hydrogen compressor may be configured between to tanks and pump hydrogen back and forth to form a heat transfer device, such as a hot water heater. A heat transfer device may be coupled with the tank or may comprise the outer surface of the tank to transfer heat to an object or to the surroundings. A closed loop may be configured having two tanks and one or two electrochemical hydrogen compressors to pump the hydrogen in a loop around the system.

A piezoelectric actuator expands or deflects in response to an applied voltage. Unfortunately, the voltage required to actuate a piezoelectric device is usually on the order of MV/cm. And most piezoelectric devices don't work well, if at all, at temperatures above 450 C. Fortunately, an oxide film actuator can work at temperatures above 450 C. and exhibits displacements of nanometers to microns at actuation voltages on the order of mV. Applying a voltage across an oxide film disposed on an ionically conducting substrate pumps oxygen ions into the oxide film, which in turn causes the oxide film to expand. This expansion can be controlled by varying the voltage based on the open-circuit potential across the oxide film and the substrate. Thanks to their low actuation voltages and ability to work at high temperatures, oxide-based actuators are suitable for applications from robotics to nuclear reactors.

The disclosure relates to a method for making an actuator based on carbon nanotubes. The method includes: providing a carbon nanotube layer; depositing a vanadium oxide (VO.sub.x) layer on the carbon nanotube layer; and annealing the VO.sub.x layer in an oxygen atmosphere to form a vanadium dioxide layer (VO.sub.2) layer. Because the drastic reversible phase transition of VO.sub.2, the actuator has giant deformation amplitude and fast response.

The disclosure relates to an actuator based on carbon nanotubes and actuating system using the same. The actuator includes: a carbon nanotube layer and a vanadium dioxide layer stacked with each other. Because the drastic, reversible phase transition of VO.sub.2, the actuator has giant deformation amplitude and fast response. An actuating system using the actuator is also provided.

There are provided stretchable solid-state electroactive polymer actuators (SSEPA) using electroactive polymers that convert between electrical energy and mechanical energy and having solid-state polymer electrolytes. More particularly, there are provided electroactive polymer (EAP) compositions comprising: 15-60 wt. % of a film-forming polymer; 5-40 wt. % of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and 10-40 wt. % of a plasticizer, solid-state polymer electrolyte (SPE) compositions comprising: 20-60 wt. % of a plasticizer, 10-60 wt. % of a film-forming polymer and 5-25 wt. % of an ionizable salt. The use of these EAP and SPE compositions in electromechanical devices, such as solid-state actuators, generators, sensors, and other energy transducers in various applications are also disclosed.

The present disclosure relates to semiconductor heterojunctions incorporating porous semiconductor materials. In one aspect, the present disclosure provides a device comprising a p-type semiconductor material comprising a nanoporous semiconductor layer and a nonporous semiconductor layer that form a heterojunction; and a flexible substrate comprising one or more of polymers on which the p-type semiconductor material is distributed such that the flexible substrate is in contact with the nonporous semiconductor layer.

The present disclosure is intended to provide an electrochemical compressor capable of preventing a liquid, such as water, from accumulating inside a piston. An electrochemical compressor according to an embodiment includes a housing chamber and a drain path. The housing chamber houses an elastic body that presses an electrochemical cell with its elastic force, and is configured to receive part of a gas compressed by the electrochemical cell, the part of the gas flowing into the housing chamber. In the electrochemical cell, the gas is supplied to an anode side of a solid polymer electrolyte membrane as a partition wall, and is compressed by being moved by electricity to a cathode side opposite to the anode side. The drain path allows a liquid in the housing chamber to be drained out of the housing chamber.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.