Abstract: Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

Abstract: Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

Abstract: Disclosed herein are real time hydrogen self-supplied alkaline membrane fuel cell that operates with hydrogen produced in situ. The hydrogen self-supplied alkaline membrane fuel cell can comprise (i) a hydrogen generation reactor that provides continuous, on-demand supply of hydrogen, wherein the hydrogen generation reactor produces hydrogen by reacting metal particles with water in the presence of an alkaline catalyst, and (ii) a membrane electrode assembly adapted to receive an oxidant and a fuel stream containing hydrogen produced in the hydrogen generation reactor. The membrane electrode assembly comprises an electrolyte membrane and at least two electrodes. The electrolyte membrane can comprise cellulose and the electrolyte can comprise a base such as aqueous potassium hydroxide. Methods for operating an alkaline membrane fuel cell are also disclosed.

Abstract: A space efficient photo-bioreactor. The bioreactor grows microalgae in a tall array of transparent flooded tubes. A nutrient media is circulated through the tubes. The array is configured to maximize the amount of sunlight falling upon each tube so that growth of the microalgae is as uniform as possible. A vertically-oriented gasser tube is provided. Gas is injected into this gasser tube along with the liquid nutrient medium. A bubble-size limiter is employed in the gas injector. The flow rates are configured so that the liquid nutrient medium and injected gas remain within the vertical gasser tube for 30 seconds or more.

Abstract: A space efficient photo-bioreactor. The bioreactor grows microalgae in a tall array of transparent flooded tubes. A nutrient media is circulated through the tubes. The array is configured to maximize the amount of sunlight falling upon each tube so that growth of the microalgae is as uniform as possible. A vertically-oriented gasser tube is provided. Gas is injected into this gasser tube along with the liquid nutrient medium. A bubble-size limiter is employed in the gas injector. The flow rates are configured so that the liquid nutrient medium and injected gas remain within the vertical gasser tube for 30 seconds or more.

Abstract: A space efficient photo-bioreactor. The bioreactor grows microalgae in a tall array of transparent flooded tubes. A nutrient media is circulated through the tubes. The array is configured to maximize the amount of sunlight falling upon each tube so that growth of the microalgae is as uniform as possible. A vertically-oriented gasser tube is provided. Gas is injected into this gasser tube along with the liquid nutrient medium. A bubble-size limiter is employed in the gas injector. The flow rates are configured so that the liquid nutrient medium and injected gas remain within the vertical gasser tube for 30 seconds or more.

Abstract: A fuel cell design which incorporates an alkaline membrane. The membrane is preferably made of specially selected commercial filter paper. The membrane is impregnated with a solution of water and potassium hydroxide. The membrane provides a novel, inexpensive method of introducing potassium hydroxide into the cell and containing it in the active area. Flexible carbon fiber films are used as electrodes. These are coated with a catalyzing film of nickel, iron, and/or cobalt, rather than a precious metal such as platinum.

Abstract: Dendritic cooling layers for printed circuit boards and method of fabrication thereof. The dendritic cooling layers may have non-intuitive dendritic structures that minimize peak temperature. The dendritic cooling layers may also be compatible with current PCB fabrication techniques. The dendritic cooling layers may have an adjustable tolerance to meet fabrication limits. The current invention also contemplates a method of generating a dendritic high conductivity path suitable for printed circuit boards. The methodology comprises the replacement of low conductivity materials with high conductivity materials such that the optimal ratio can be obtained to minimize heat flow resistance, while also maintaining lower costs of production.

Abstract: A space efficient photo-bioreactor. The bioreactor grows microalgae in a tall array of transparent flooded tubes. A nutrient media is circulated through the tubes. The array is configured to maximize the amount of sunlight falling upon each tube so that growth of the microalgae is as uniform as possible. Gassing/degassing systems are attached to the array of tubes at appropriate locations. These introduce carbon dioxide and remove oxygen. Cooling systems are preferably also provided so that the circulating media can be maintained at a desired temperature. Microalgae are harvested from the photo-bioreactor. The microalgae is filtered and dried. Lipids are then extracted from the microalgae. These lipids are made into biodiesel through a trans-esterification process. The lipids may be used to make other products as well.

Abstract: A prosthetic heart valve holder includes a set of jaws. Each jaw includes a distal end adapted for coupling to the prosthetic heart valve and a proximal end. A hinge assembly pivotally couples the jaws together between the distal and proximal ends. The hinge assembly allows movement of the jaws between an engaged position for grasping the prosthetic heart valve and an disengaged position in which the prosthetic heart valve is free from the distal ends. A locking collar is attached to the jaws and is movable between a first position in which the proximal ends are free from the collar, and a second position in which the collar holds the proximal ends of the jaws whereby the distal ends are held in position to engage the prosthetic heart valve.