Abstract: A compact muffler (40) for an engine exhaust system, which is particularly applicable for use with small, reciprocating piston two-stroke engines of the type used on unmanned aerial vehicles (UAVs). The compact muffler (40) comprises an exhaust gas flow path (67) between an inlet (61) and an outlet (63). The exhaust gas flow path (67) comprises a plurality of adjacent flow passages (65), wherein at least two of the adjacent flow passages (65) are fluidly connected in series to enable the flow of exhaust gas from one to the other along the flow path (67). The adjacent flow passages (65) are configured for fluid flow therealong in opposed directions. A bypass passage (70) is provided between the two adjacent flow passages (65) for further communication between the two flow passages and to promote an equalisation of fluid pressure within the two adjacent passages (65). A UAV having an internal combustion engine (31) fitted with an exhaust system comprising the compact muffler (40) is also disclosed.

Abstract: A compact muffler (40) for an engine exhaust system, which is particularly applicable for use with small, reciprocating piston two-stroke engines of the type used on unmanned aerial vehicles (UAVs). The compact muffler (40) comprises an exhaust gas flow path (67) between an inlet (61) and an outlet (63). The exhaust gas flow path (67) comprises a plurality of adjacent flow passages (65), wherein at least two of the adjacent flow passages (65) are fluidly connected in series to enable the flow of exhaust gas from one to the other along the flow path (67). The adjacent flow passages (65) are configured for fluid flow therealong in opposed directions. A bypass passage (70) is provided between the two adjacent flow passages (65) for further communication between the two flow passages and to promote an equalisation of fluid pressure within the two adjacent passages (65). A UAV having an internal combustion engine (31) fitted with an exhaust system comprising the compact muffler (40) is also disclosed.

Abstract: A fingertip covering for prevention of smudges, dirt accumulation and germ transfer to and from an electronic touchscreen device. The covering comprises a cylindrical section with an open end and a closed end, and a two-part construction. An antistatic microfiber material comprises the contact region and interface with the touchscreen, while an elastic material comprises the body of the covering. The use of a microfiber contact region provides a conductive interface for use with multiple touchscreen technologies. A fingernail opening is provided to accommodate users with longer finger nails, while the elastic body region conforms to different size fingers. The disclosed invention is an alternative to touchscreen covers that dull the display, reduce feedback and are prone to imbedded air bubbles that erode touch sensitivity.

Abstract: In a sodium-sulphur cell having a solid electrolyte separating sodium from a cathodic region containing sulphur/polysulphides in a graphite felt, a cathode current collector is formed of an aluminium substrate on which is an interstrate layer of nickel-chromium alloy covered by a coating of titanium oxide or other electronically conductive oxide intrinsically inert to the cathodic reactant.

Abstract: In an electric cell having a solid electrolyte which bounds on one side a mpartment for liquid anode and on its opposite side a compartment for liquid cathode, the liquid anode compartment is made of very limited capacity. The bulk of the liquid anode required by the cell is held in a reservoir and fed to the liquid anode compartment by a capillary duct to provide a restricted feed which limits the flow of liquid anode therebetween. The reservoir may be disposed within the cell, or outside the cell, and may supply liquid anode to several cells.

Abstract: In a sodium-sulphur electric cell, a circuit breaking device responsive to temperature or current is inserted inside the cell in series in the internal electric circuit of the cell so as to open circuit the cell in the event of either an abnormal cell temperature or current. The circuit breaking device may be in the form of a fusible metal link or a temperature sensitive switch.

Abstract: A sodium-sulphur electric cell is provided having a sulphur compartment in hich a current collector of hollow form extends. The space inside the current collector is used as an expansion space for products arising from reaction of sodium and sulphur. The walls of the current collector may be tapered to arrange that the current density along it is substantially constant.