Abstract:
Rewritable signs (100, 1300) that include bistable cholesteric liquid crystal layers (102, 1402, 1404, 1406) are provided. According to one embodiment a rewritable sign (100) is devoid of circuitry for establishing electric fields in localize regions for writing information to the rewritable sign (100), and is consequently inexpensive. In the latter embodiment, a separate information writer (400) that includes an array of pixel electrodes (404) that is driven by an active matrix (602) is used to write information on the rewritable sign. According to another embodiment a rewritable sign (1300) includes three cholesteric liquid layers (1402, 1404, 1406) each of which reflects a different primary color. The three cholesteric liquid crystal layers (1402, 1404, 1406) are interleaved with sets of conductive lines (1316, 1320, 1322, 1324) that are used to apply signals to the cholesteric liquid crystal layers (1402, 1404, 1406) for the purpose of writing information.
Abstract:
A fuel cell power source (100) for use in electronic systems includes a fuel cell system (130) and a control means (150). The control means (150) computes net power requirements of a load device from one or more power functional information sources; and determines an operating point of the fuel cell system (130) by matching the net power requirements with the power characteristics of the fuel cell system (130).
Abstract:
A fuel cell (100) includes a membrane electrode assembly (110) located together with a layer of porous gas diffusion material (150). The membrane electrode assembly (110) is activated by supplying reactants thereto. The porous gas diffusion material layer (150) operates to selectively limit the amount of reactants reaching localized areas of the membrane electrode assembly (110) in order to reduce hot spots.
Abstract:
A fuel cell device has a composite particle electrode (200) formed using particles (210) having a combination of ion conductor material, electron conductor material, and catalyst material. Each composite particle (210) is preferably formed to have a substantially spherical outer layer (480) of ion conductor material (481) with conductive and catalyst particles (482, 484) are dispersed throughout the outer layer (480). An array of composite particles (210) is layered in a substantially structured or ordered manner on a membrane support structure (220) to form the fuel cell electrode. A fuel cell electrode so formed has interstitial gaps between the composite particles that result in a structure permeable to oxygen and other fluids.
Abstract:
A fuel cell (200) includes a membrane electrode assembly (210) located together with a layer of porous, Z-axis electrically conductive, positive temperature coefficient (PTC) material (250). The membrane electrode assembly (210) is activated by supplying reactants thereto. The PTC material (250) operates to selectively limit the amount of electrons collected from localized areas of the membrane electrode assembly (210) in order to reduce hot spots.
Abstract:
A small fuel cell (10) powers a portable electronic device (12) and contains a fuel reservoir (14) and a device (16) that measures the amount of liquid fuel (18) that is in the reservoir. The fuel cell operates on hydrogen that is obtained from a liquid hydrocarbon fuel, such as alcohol or other hydrocarbons. The liquid fuel is typically converted into hydrogen by a reforming process. The reservoir that is connected to the fuel cell has an indicia (19) that is readable by a human user of the portable electronic device, for measuring the amount of liquid hydrocarbon fuel that is present in the reservoir. Typically, the indicia consist of a sight glass, a capacitive element, a resistive element, a transparent portion of the reservoir, a float, or an acoustic transmitter coupled with an acoustic receiver.
Abstract:
Oxides of carbon and other impurities are removed from a hydrogen fuel supply stream (12) for a fuel cell (30). A getter element (20) sufficient for chemisorbing the oxides of carbon from the hydrogen is removably connected to the fuel cell anode side. The fuel stream is passed through the getter element so as to chemisorb the oxides of carbon onto the getter, thereby providing a purified stream of hydrogen (26) to the fuel cell anode. The getter is removed from the fuel cell when the getter when spent and replaced with a fresh getter.
Abstract:
A method (50) of altering content provided to a user includes the steps of creating (60) a user profile based on past physiological measurements of the user, monitoring (74) at least one current physiological measurement of the user, and altering (82) the content provided to the user based on the user profile and the at least one current physiological measurement. The user profile can be created by recording a plurality of inferred or estimated emotional states (64) of the user which can include a time sequence of emotional states, stimulus contexts for such states, and a temporal relationship between the emotional state and the stimulus context. The content can be altered in response to the user profile and measured physiological state by altering at least one among an audio volume, a video sequence, a sound effect, a video effect, a difficulty level, a sequence of media presentation.
Abstract:
A gas pressure regulator (100) includes a mechanical primary stage (102), preferably including a spring valve, and an electronic secondary stage (104), preferably including a micromachined pressure regulator, the combination of the mechanical primary stage and the electronic secondary stage suitable for relatively precise low pressure near zero flow rates with reasonable energy consumption rates, such as encountered when supplying fuel to a low power fuel cell system.
Abstract:
A thermo-responsive polymer is incorporated into a fuel cell (50) in order to maintain optimum hydration of the polymer electrolyte membrane. The thermo-responsive polymer (52) is situated proximate to the membrane electrode assembly (54) such that fuel or oxidant gas passes (56) through the thermo-responsive polymer to the membrane electrode assembly. The thermo-responsive polymer swells or shrinks in response to changes in the operating temperature of the membrane electrode assembly, altering the flow rate of the fuel or oxidant gas passing through the thermo-responsive polymer.