"Wind speed Wind speed, or wind flow velocity, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Note that wind direction is usually almost parallel to isobars (and not perpendicular, as one might expect), due to Earth's rotation. Wind speed affects weather forecasting, aviation and maritime operations, construction projects, growth and metabolism rate of many plant species, and countless other implications. Wind speed is now commonly measured with an anemometer, but can also be classified using the older Beaufort scale, which is based on personal observation of specifically defined"
"measured by the propagation speed of ultrasound signals or by the effect of ventilation on the resistance of a heated wire. Another type of anemometer uses pitot tubes that take advantage of the pressure differential between an inner tube and an outer tube that is exposed to the wind to determine the dynamic pressure, which is then used to compute the wind speed. Sustained wind speeds are reported globally at a height and are averaged over a 10‑minute time frame. The United States reports winds over a 1‑minute average for tropical cyclones, and a 2‑minute average within weather observations. India"
"the gas in question. This mass flux makes the FluxNet project a valuable tool to scientists trying to monitor long term changes in trace gas flux within the atmosphere. Many different forms of anemometer exist on the current market. Unfortunately, the majority of the anemometers can only measure wind velocity in one plane and require a certain start-up wind speed. Sonic anemometers are solid state devices that measure the wind speed by passing ultrasonic sound waves through the moving air. As wind speed changes, so does the air density and when the density changes, so does the speed of sound."
"anemometers are also used, wherein the velocity is inferred by the time length of a repeating pulse of current that brings the wire up to a specified resistance and then stops until a threshold ""floor"" is reached, at which time the pulse is sent again. Hot-wire anemometers, while extremely delicate, have extremely high frequency-response and fine spatial resolution compared to other measurement methods, and as such are almost universally employed for the detailed study of turbulent flows, or any flow in which rapid velocity fluctuations are of interest. An industrial version of the fine-wire anemometer is the thermal flow meter,"
"a measurement of velocity in 1-, 2-, or 3-dimensional flow. The spatial resolution is given by the path length between transducers, which is typically 10 to 20 cm. Ultrasonic anemometers can take measurements with very fine temporal resolution, 20 Hz or better, which makes them well suited for turbulence measurements. The lack of moving parts makes them appropriate for long-term use in exposed automated weather stations and weather buoys where the accuracy and reliability of traditional cup-and-vane anemometers are adversely affected by salty air or dust. Their main disadvantage is the distortion of the air flow by the structure supporting"
"of air filling the space in question. The instrument that measures airflow is called an airflow meter. Anemometers are also used to measure wind speed and indoor airflow. There are a variety of types, including straight probe anemometers, designed to measure air velocity, differential pressure, temperature, and humidity; rotating vane anemometers, used for measuring air velocity and volumetric flow; and hot-sphere anemometers. Anemometers may use ultrasound or resistive wire to measure the energy transfer between the measurement device and the passing particles. A hot-wire anemometer, for example, registers decreases in wire temperature, which can be translated into airflow velocity by"
"from: In aviation, airspeed is typically measured in knots. In weather stations with high wind speeds, the pitot tube is modified to create a special type of anemometer called pitot tube static anemometer. Notes Bibliography Pitot tube A pitot ( ) tube, also known as pitot probe, is a flow measurement device used to measure fluid flow velocity. The pitot tube was invented by the French engineer Henri Pitot in the early 18th century and was modified to its modern form in the mid-19th century by French scientist Henry Darcy. It is widely used to determine the airspeed of an"
"By measuring the change in time it takes for the ultrasonic sound wave to make its way from the emitter to the sensor, the sonic anemometer can measure the total air speed as well as its direction. This sensor works because Infrared light is absorbed by a variety of gases at different wavelengths within the spectrum including methane, carbon monoxide, carbon dioxide and oxygen. To measure the concentration, a beam of light is emitted into the air sample. By measuring the difference between the input and output of the infrared beam, the sensor can determine the amount of the trace"
"usually less for gravimeters, so that resolution can be increased by processing the output with a longer ""time constant"". Accelerometer An accelerometer is a device that measures proper acceleration. Proper acceleration, being the acceleration (or rate of change of velocity) of a body in its own instantaneous rest frame, is not the same as coordinate acceleration, being the acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s. By contrast, accelerometers in free fall (falling"
"the Carlyle Home Guard, but only served for three months. In 1869, he went to St. Louis, Missouri as manager of Peck's Planning Mills. It was around this time, that he invented an anemometer, for recording the direction of the wind. He also invented a ""registering step"" for street cars, that recorded the number of passengers entering a streetcar; and a ""street indicator"" geared from the axle of a trolley that showed each street in succession, from an illuminated box, as the car passed. Shortly thereafter, he invented and patented the ""Recording Lumber Measure"", a machine which automatically measured and"
"Accelerometer An accelerometer is a device that measures proper acceleration. Proper acceleration, being the acceleration (or rate of change of velocity) of a body in its own instantaneous rest frame, is not the same as coordinate acceleration, being the acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.81 m/s) will measure zero. Accelerometers have multiple"
"suspended at the station, the official weather observer there stayed on duty and continued to make wind speed readings. At 4:45 a.m. EDT, August 24, he noted that the wind speed indicator was ""pegged"" at a position a little beyond the instrument's highest value of 100 kt (115 mph; 185 km/h), at a point he estimated to be around 110 kt (127 mph; 204 km/h). The needle reportedly remained ""fixed"" at this location for 3–5 minutes before dropping to ""0"" when the anemometer failed. These observations were closely corroborated by two other observers. He also indicated that the weather conditions"
"can be made to increase or decrease the speed and new chart is attached. Barograph A barograph is a barometer that records the barometric pressure over time. Alexander Cumming, a watchmaker and mechanic, has a claim to having made the first effective recording barograph in the 1760s using an aneroid cell. Cumming created a series of barometrical clocks, including one for King George III. However, this type of design fell out of favour. Since the amount of movement that can be generated by a single aneroid is minuscule, up to seven aneroids (so called Vidie-cans) are often stacked ""in series"""
"Tachometer A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common. The word comes from Greek ""ταχος"" (""tachos"" ""speed"") and ""metron"" (""measure""). Essentially the words tachometer and speedometer have identical meaning: a device that measures speed. It is by arbitrary convention that in the automotive world one is used for engine and the other for vehicle speed. In formal engineering nomenclature, more precise terms"
"is more common place, as in Adjuntas in the Cordillera Central and in the Sierra de Luquillo, the rain was over , with recorded in Adjuntas. The anemometer located in Puerta de Tierra lost one of its cups at 11:44 am on September 13, just when it had registered a maximum speed of per hour—a speed that was sustained for five consecutive minutes. Previously the same instrument had measured per hour for one minute. Because these measurements were taken from San Felipe's eye, at the time, it seemed possible that some estimates of per hour near the center of the"
"accelerometric sensors to detect movement of a sleeper, so that it can wake the person when he/she is not in REM phase, in order to awaken the person more easily. A microphone or eardrum is a membrane that responds to oscillations in air pressure. These oscillations cause acceleration, so accelerometers can be used to record sound.. A 2012 study found that voices can be detected by smartphone accelerometers in 93% of typical daily situations.. Conversely, carefully designed sounds can cause accelerometers to report false data. One study tested 20 models of (MEMS) smartphone accelerometers and found that a majority were"
"the kinetic energy of the molecules within air. A barometer measures atmospheric pressure, or the pressure exerted by the weight of the Earth's atmosphere above a particular location. An anemometer measures the wind speed and the direction the wind is blowing from at the site where it is mounted. A hygrometer measures the relative humidity at a location, which can then be used to compute the dew point. Radiosondes directly measure most of these quantities, except for wind, which is determined by tracking the radiosonde signal with an antenna or theodolite. Supplementing the radiosondes a network of aircraft collection is"
"Pneumograph A pneumograph, also known as a pneumatograph or spirograph, is a device for recording velocity and force of chest movements during respiration. There are various kinds of pneumographic devices, which have different principles of operation. In one mechanism, a flexible rubber vessel is attached to the chest. The vessel is equipped with sensors. Others are impedance based. In these methods, a high frequency (tens to hundreds of kHz) low amplitude current is injected across the chest cavity. The voltage resulting from this current injection is measured and the resistance is derived from the application of Ohm's law (R ="
"employ Doppler radar units beneath the train to measure speed independently. In analogue audio recording, a tachometer is a device that measures the speed of audiotape as it passes across the head. On most audio tape recorders the tachometer (or simply ""tach"") is a relatively large spindle near the ERP head stack, isolated from the feed and take-up spindles by tension idlers. On many recorders the tachometer spindle is connected by an axle to a rotating magnet that induces a changing magnetic field upon a Hall effect transistor. Other systems connect the spindle to a stroboscope, which alternates light and"
"team confirmed that the instrument was regularly inspected and calibrated, and that the reading was during the passage of the eyewall. On 26 January 2010, nearly 14 years later, the World Meteorological Organization announced that the wind gust was the highest recorded worldwide. This gust surpassed the previous non-tornadic wind speed of 372 km/h (231 mph) on Mount Washington in the United States in April 1934. The long delay was partly due to the anemometer not being owned by the BoM, and as a result the agency did not enact a follow-up investigation. Despite the high winds, the anemometer and"
"Speedometer A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the 1900s, and as standard equipment from about 1910 onwards. Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an airspeed indicator. Charles Babbage is credited with creating an early type of a speedometer, which was usually fitted to locomotives. The electric speedometer was invented by the Croatian"
"laid out above. Wingate test The ergonometer test (also known as the ""ergonometer Anaerobic Test (WAnT)"") is an anaerobic exercise test, most often performed on a stationary bicycle, that measures peak anaerobic power and anaerobic capacity. The test, which can also be performed on an arm crank ergometer, consists of a set time pedalling at maximum speed against a given resistance. The prototype test based on the Cumming’s test was introduced in 1974, at the Wingate Institute and has undergone modifications as time has progressed. The Wingate test has also been used as a basis to design newer tests in"
"Wingate test The ergonometer test (also known as the ""ergonometer Anaerobic Test (WAnT)"") is an anaerobic exercise test, most often performed on a stationary bicycle, that measures peak anaerobic power and anaerobic capacity. The test, which can also be performed on an arm crank ergometer, consists of a set time pedalling at maximum speed against a given resistance. The prototype test based on the Cumming’s test was introduced in 1974, at the Wingate Institute and has undergone modifications as time has progressed. The Wingate test has also been used as a basis to design newer tests in the same vein,"
"they existed. Speedometer A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the 1900s, and as standard equipment from about 1910 onwards. Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an airspeed indicator. Charles Babbage is credited with creating an early type of a speedometer, which was usually fitted to locomotives. The electric speedometer was invented by"
"direction measurements from the same instrument. The speed of the fan is measured by a rev counter and converted to a windspeed by an electronic chip. Hence, volumetric flow rate may be calculated if the cross-sectional area is known. In cases where the direction of the air motion is always the same, as in ventilating shafts of mines and buildings, wind vanes known as air meters are employed, and give satisfactory results. Hot wire anemometers use a fine wire (on the order of several micrometres) electrically heated to some temperature above the ambient. Air flowing past the wire cools the"
"accelerometers are often small ""micro electro-mechanical systems"" (MEMS), and are indeed the simplest MEMS devices possible, consisting of little more than a cantilever beam with a proof mass (also known as ""seismic mass""). Damping results from the residual gas sealed in the device. As long as the Q-factor is not too low, damping does not result in a lower sensitivity. Under the influence of external accelerations the proof mass deflects from its neutral position. This deflection is measured in an analog or digital manner. Most commonly, the capacitance between a set of fixed beams and a set of beams attached"
"Acceleromyograph An acceleromyograph is a piezoelectric myograph, used to measure the force produced by a muscle after it has undergone nerve stimulation. Acceleromyographs are most commonly employed after the use of anesthetics to test for residual muscle weakness in the patient. Patients who undergo anesthesia may receive a drug that paralyzes muscles, improving operating conditions for the surgeon. Longer-acting drugs have higher residual blockade in the PACU or ICU than shorter acting drugs. Different clinical tests to measure or exclude evidence of residual muscle weakness have been described. Small degrees of muscle blockade can only accurately be measured by the"
"accelerometer, in its simplest form, is a damped mass on the end of a spring, with some way of measuring how far the mass has moved on the spring in a particular direction, called an 'axis'. Accelerometers are often calibrated to measure g-force along one or more axes. If a stationary, single-axis accelerometer is oriented so that its measuring axis is horizontal, its output will be 0 g, and it will continue to be 0 g if mounted in an automobile traveling at a constant velocity on a level road. When the driver presses on the brake or gas pedal,"
"which follows the same concept, but uses two pins or strings to monitor the variation in temperature. The strings contain fine wires, but encasing the wires makes them much more durable and capable of accurately measuring air, gas, and emissions flow in pipes, ducts, and stacks. Industrial applications often contain dirt that will damage the classic hot-wire anemometer. In laser Doppler velocimetry, laser Doppler anemometers use a beam of light from a laser that is divided into two beams, with one propagated out of the anemometer. Particulates (or deliberately introduced seed material) flowing along with air molecules near where the"
"used to synchronize several tape machines together, but only if in addition to the tach signal, a directional signal is transmitted, to tell slave machines in which direction the master is moving. Tachometer A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common. The word comes from Greek ""ταχος"" (""tachos"" ""speed"") and ""metron"" (""measure""). Essentially the words tachometer and speedometer have identical meaning: a"
"accelerometer-equipped smartphones also have ACN software available for download. ACN systems are activated by detecting crash-strength accelerations. Accelerometers are used in vehicle Electronic stability control systems to measure the vehicle's actual movement. A computer compares the vehicle's actual movement to the driver's steering and throttle input. The stability control computer can selectively brake individual wheels and/or reduce engine power to minimize the difference between driver input and the vehicle's actual movement. This can help prevent the vehicle from spinning or rolling over. Some pedometers use an accelerometer to more accurately measure the number of steps taken and distance traveled than"
"in knots and degrees. Note that a number of additional factors come into play when converting the measurements from the masthead anemometer into the true wind if a high degree of accuracy is required, including the following: In the presence of a current, the true wind is considered to be that measured on the craft drifting with the water over the bottom, and wind with respect to the sea bed as the ""ground"" or ""geographical wind"". The apparent wind on board (a boat) is often quoted as a speed measured by a masthead transducer containing an anemometer and wind vane"
"Knemometry Knemometry (Greek η κνημη the lower leg) is the medical term for measuring the distance between knee and heel of a sitting child or adolescent using a technical device, the knemometer. Knemometric measurements show a measurement error of less than 160 µm (0.16 mm) and enable illustrating growth at intervals of few weeks (short-term growth). Ignaz Maria Valk developed this technique in 1983 in Nijmegen/Netherlands. It is being practiced since and used for basic research in growth and the treatment of growth disorders. Hermanussen introduced the mini-knemometer for accurate growth measurements of prematures and newborn infants. Mini-knemometry determines the"