A system for measuring the difference between a property of a first target and a property of a second target, the system comprising a first member and a second member, wherein the first member comprises a first pattern, and the speed of rotation of the first member is configured to be based on the property of the first target; and the second member comprises a second pattern wherein, the speed of rotation of the second member is configured to be based on the property of the second target, further wherein the first and second pattern are angularly-varying and are configured to generate an interference pattern by their interaction when the first and second members have a relative difference in their rotational speeds, the interference pattern being indicative of the magnitude of this difference.

Systems and methods for sensing water device run time, transmitting this data via a network to a database which analyzes, records and reports the individual run times and the aggregate use over any given timeframe. Sensors used to measure device use time do not directly measure flow rate, and may sense device run time by sensing water flow, through electronic signals, vibration, etc. The sensors may be battery powered and transmit discrete data packets via radio frequency to powered node units. A system of node units communicates with a central internet gateway which uploads the data packets to a cloud-based database which organizes, analyzes, stores and reports the information. The system allocates the cost of water flowing through a common water meter to a plurality of individual units within a collection of geographically proximate units. The systems are useful in multi-unit buildings or complexes having stacked plumbing.

A system and method for detecting leaks in an enclosure having a port and intended to prevent liquid material from exchanging into or out of the enclosure. A vacuum pump is coupled to the port and the enclosure is subjected to an applied vacuum pressure. Measurements of the mass and pressure within the enclosure while subject to the applied vacuum pressure are compared to expected values to detect a leak. In some embodiments, the physical arrangement of a valve of the enclosure is measured and compared to expected values to detect a leak.

A computing system having a memory and a processor configured to process flow data packets (FDPs) collected from a set of sensor devices, each installed in a toilet that collects a flow data packet (FDP) in response to a detected event, wherein each FDP includes a sequence of flow rate values collected over the course of the detected event. The processor is configured to: issue a first type of alert in response to a number of flow rate values in a current FDP being above a threshold; issue a second type of alert in response to a detected abnormal behavior of the current FDP relative to previously collected FDPs for an associated toilet; and issue a third type of alert based on a water usage for the toilet, wherein the water usage is based on calculated flow rate for a toilet determined from at least one FDP.

A self-charging sensor (SCS) adapted for use in a toilet or the like. The SCS includes a housing having a rechargeable battery; a turbine module having a multilevel impeller having offset wheels that are adapted to be driven by a fluid flow via an inlet port during an event, wherein a rotation of the impeller causes the turbine module to generate electricity that recharges the rechargeable battery; and a processing module that collects count data associated with the rotation during the event; and an attachment component adapted to seat the housing on an overflow tube.

It is an object of the present invention to enhance reliability of an allowable limit conductance used for setting a threshold value for evaluating sealability of a test object, and further, enhance reliability of the sealability evaluation. By leak testing a test object 9A with a sealing defect 9g, a leakage characteristic that shows a relationship between an internal-external pressure difference and a leak flow rate is obtained. A conductance of a test object with a similar artificial leak 9B having a similar artificial leak device 29 disposed therein, conducting the leak-detected substance is measured. The similar artificial leak device 29 has a leakage characteristic similar to the obtained leakage characteristic. An allowable limit conductance is obtained based on results of the measurement. Sealability of a test object 9 is evaluated based on a threshold value set with a standard artificial leak device 9S having the allowable limit conductance.

Methods and systems for estimating energy loss or controlling ventilation in a building based on measurements of air pressure differences between inside and outside of the building envelope. The measured differences may be used to calculate air leakage and corresponding energy loss, or to control a ventilation system in order to minimize air pressure difference and thereby the energy loss.

Energy loss may be calculated by obtaining an estimate of a correspondence between air flow through a building envelope and a difference in air pressure on respective sides of the envelope, obtaining a measurement of a current difference in air pressure on respective sides of the envelope, calculating a current flow of air per unit time through the envelope based on said correspondence and said current difference in air pressure, and providing a representation of the calculated current flow of air per unit time through the envelope.

An apparatus for detecting a puncture comprises a housing comprising a plurality of compartments. Each compartment comprises an opening for receiving a flow of air into the compartment. Each compartment also comprises a detection element mounted on an axle, the axle having a first end and a second end and being secured at said first end and said second end within the compartment. The detection element is rotatable about the axle and when a flow of air passes through the opening into the compartment, the detection element rotates around the axle in response to the flow of air.

A method for measuring wafer bow value comprising the following steps is provided. Place a wafer on a wafer chuck apparatus. A gas inlet process is performed on gas inlet passageways of a passageway pair of the wafer chuck apparatus. A gas outlet process is performed on gas outlet passageways of a passageway pair of the wafer chuck apparatus. A leak rate of each channel pair is measured by the control unit when the wafer is placed on the wafer chuck apparatus and during the gas inlet process and gas outlet process are performed. A wafer bow value of the wafer on the wafer chuck apparatus is estimated by the leak rate of the passageway pair. A wafer chuck apparatus is provided. A semiconductor process flow is provided.

An air monitoring system measures tan amount of pollutant in the air. The system includes a plurality of air quality sensor devices arranged within a selected area. Each of the air quality sensor devices is configured to measure air pollutant levels in the selected area, and includes at least one sensor operatively coupled to a controller, wherein the controller is configured to receive a measured input from the at least one sensor. A wireless communication device is coupled to the controller, and is configured to communicate with a central server device.