A linear reciprocating engine may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The engine may further include a first piston rod portion extending from a first face of the double-faced piston through the first combustion chamber, and a second piston rod portion extending from a second face of the piston through the second combustion chamber. Passageways in the piston rod portions may be configured to communicate gases between the combustion chamber and a location outside the cylinder and configured to prevent gases from being exchanged between the cylinder and a location outside the cylinder via a path that crosses both face of the piston.

A hydraulic cylinder is disclosed. The hydraulic cylinder may have an outer cylindrical tube including an open end, a first female threaded portion, and a second female threaded portion. The hydraulic cylinder may also have a movable element received in the outer cylindrical tube through the open end. Further, the hydraulic cylinder may have a sleeve holder engaged with the first female threaded portion to seal an annular space between the outer cylindrical tube and the movable element. The sleeve holder may have a first male threaded portion mating with the first female threaded portion. In addition, the hydraulic cylinder may have a locking ring engaged with the second female threaded portion to secure the sleeve holder to the outer cylindrical tube. The locking ring may have a second male threaded portion mating with the second female threaded portion.

A variable displacement hydraulic device comprising: a housing having an inlet for receiving hydraulic fluid and an outlet for outputting the hydraulic fluid, the housing having a reciprocation axis; a first cylinder positioned in the housing along the reciprocation axis, the first cylinder having a first input for receiving the hydraulic fluid on a first intake stroke and a first output for ejecting the hydraulic fluid on a first exhaust stroke; a first piston positioned for a first reciprocal motion within the first cylinder, the first piston having a first main end exposed to the hydraulic fluid and a second main end coupled to an actuator, the actuator for driving the second main end when coupled to the actuator for causing the first reciprocal motion to induce a first portion of said outputting of the hydraulic fluid; a second cylinder positioned in the first piston along the reciprocation axis, the second cylinder having a second input for receiving the hydraulic fluid on a second intake stroke and a second output for ejecting the hydraulic fluid on a second exhaust stroke; a second piston positioned for a second reciprocal motion within the second cylinder, the second piston having a first secondary end exposed to the hydraulic fluid and a second secondary end coupled to the actuator, the actuator for driving the second secondary end when coupled to the actuator for causing the second reciprocal motion to induce a second portion of said outputting of the hydraulic fluid; and a locking mechanism for inhibiting the first reciprocal motion of the first piston; wherein when engaged the locking mechanism inhibits the first portion of said outputting of the hydraulic fluid by decoupling the first piston from the actuator while continued operation of the actuator provides the second portion of said outputting of the hydraulic fluid by the second piston.

A variable displacement hydraulic device comprising: a housing having an inlet for receiving hydraulic fluid and an outlet for outputting the hydraulic fluid, the housing having a reciprocation axis; a first cylinder positioned in the housing along the reciprocation axis, the first cylinder having a first input for receiving the hydraulic fluid on a first intake stroke and a first output for ejecting the hydraulic fluid on a first exhaust stroke; a first piston positioned for a first reciprocal motion within the first cylinder, the first piston having a first main end exposed to the hydraulic fluid and a second main end coupled to an actuator, the actuator for driving the second main end when coupled to the actuator for causing the first reciprocal motion to induce a first portion of said outputting of the hydraulic fluid; a second cylinder positioned in the first piston along the reciprocation axis, the second cylinder having a second input for receiving the hydraulic fluid on a second intake stroke and a second output for ejecting the hydraulic fluid on a second exhaust stroke; a second piston positioned for a second reciprocal motion within the second cylinder, the second piston having a first secondary end exposed to the hydraulic fluid and a second secondary end coupled to the actuator, the actuator for driving the second secondary end when coupled to the actuator for causing the second reciprocal motion to induce a second portion of said outputting of the hydraulic fluid; and a locking mechanism for inhibiting the first reciprocal motion of the first piston; wherein when engaged the locking mechanism inhibits the first portion of said outputting of the hydraulic fluid by decoupling the first piston from the actuator while continued operation of the actuator provides the second portion of said outputting of the hydraulic fluid by the second piston.

The present invention provides for methods of determining telomere length of an organism and correlating the measured telomere length with mortality risk associated with telomere length in a population. The presence of shorter telomeres is associated with an increased mortality rate and increased susceptibility to certain types of diseases for an individual member of a human population.

A piston is provided for an internal combustion engine. The piston may include a cylindrical first piston portion having a first diameter, a cylindrical second piston portion of the first diameter, and a cylindrical third piston portion of a second diameter less than the first diameter located between the first piston portion and the second piston portion. The first piston portion may be configured such that prior to assembly, the first piston portion is separate from the second piston portion. The piston may also include a continuous, gapless piston ring circumscribing the third piston portion, where the piston ring may be configured such that when heated the piston ring deforms in an axial direction of the piston.

A two-cycle internal combustion engine with rear compression chamber, other than that of a crank case. This present engine has valves that can be screwed on the engine block near top dead center, and is actuated by air pressure. This present two-cycle engine uses an oil sump similar to that of a four-cycle engine, which eliminates the need to premix oil with the fuel. This present engine has a stationary piston which operates within a movable piston to form a rear-compression chamber. The movable piston has ports near its crown to transfer charge to the combustion chamber. The movable piston also has ports near bottom of its skirt to allow the fuel and air mixture to enter the rear compression chamber. This engine has a piston seat which is adapted to connect the movable piston to the connecting rod.

A two-cycle internal combustion engine with rear compression chamber, other than that of a crank case. This present engine has valves that can be screwed on the engine block near top dead center, and is actuated by air pressure. This present two-cycle engine uses an oil sump similar to that of a four-cycle engine, which eliminates the need to premix oil with the fuel. This present engine has a stationary piston which operates within a movable piston to form a rear-compression chamber. The movable piston has ports near its crown to transfer charge to the combustion chamber. The movable piston also has ports near bottom of its skirt to allow the fuel and air mixture to enter the rear compression chamber. This engine has a piston seat which is adapted to connect the movable piston to the connecting rod.

A two-cycle internal combustion engine with rear compression chamber, other than that of a crank case. This present engine has valves that can be screwed on the engine block near top dead center, and is actuated by air pressure. This present two-cycle engine yet uses an oil sump similar to that of a four-cycle engine, which eliminating the need to premix oil with the fuel. This present engine has a stationary piston which operates within a movable piston to form a rear-compression chamber. The movable piston has ports near its crown to transfer charge to the combustion chamber. The movable piston also has ports near bottom of its skirt to allow the fuel and air mixture to enter the rear compression chamber. This engine has a piston seat which is adapted to connect the movable piston to the connecting rod.

A cam and follower apparatus adapted to translate the force of a piston to turn the shaft of an engine. The cam profile is made of three intersecting circles allowing for one follower to be near top dead center while another follower is near bottom dead center. The surface of the follower is a circle which shares the same center point and radius with the circles of the cam profile. The surface of the follower also closely intersects the axis of the follower preventing the follower from spinning like a roller follower. The follower can therefore spread the force from the piston to a wider area on the cam for longevity.