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Noise-canceling Headphones
Noise-cancelling headphones reduce unwanted Ambient noise level, ambient sounds using active noise control. This is distinct from passive headphones which, if they reduce ambient sounds at all, use techniques such as soundproofing. Noise cancellation makes it possible to listen to audio content without raising the volume excessively. It can also help a passenger sleep in a noisy vehicle such as an airliner. In the aviation environment, noise-cancelling headphones increase the signal-to-noise ratio significantly more than passive noise attenuating headphones or no headphones, making hearing important information such as safety announcements easier. Noise-cancelling headphones can improve listening enough to completely offset the effect of a distracting concurrent activity. Theory To cancel the lower-frequency portions of the noise, noise-cancelling headphones use active noise control or ANC. A microphone captures the targeted ambient sounds, and a small amplifier generates sound wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambient Noise Level
In atmospheric sounding and noise pollution, ambient noise level (sometimes called background noise level, reference sound level, or room noise level) is the background sound pressure level at a given location, normally specified as a reference level to study a new intrusive sound source. Ambient sound levels are often measured in order to map sound conditions over a spatial regime to understand their variation with locale. In this case the product of the investigation is a sound level contour map. Alternatively ambient noise levels may be measured to provide a reference point for analyzing an intrusive sound to a given environment. For example, sometimes aircraft noise is studied by measuring ambient sound without presence of any overflights, and then studying the noise addition by measurement or computer simulation of overflight events. Or roadway noise is measured as ambient sound, prior to introducing a hypothetical noise barrier intended to reduce that ambient noise lev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence J
Lawrence may refer to: Education Colleges and universities * Lawrence Technological University, a university in Southfield, Michigan, United States * Lawrence University, a liberal arts university in Appleton, Wisconsin, United States Preparatory & high schools * Lawrence Academy at Groton, a preparatory school in Groton, Massachusetts, United States * Lawrence College, Ghora Gali, a high school in Pakistan * Lawrence School, Lovedale, a high school in India * The Lawrence School, Sanawar, a high school in India Research laboratories * Lawrence Berkeley National Laboratory, United States * Lawrence Livermore National Laboratory, United States People * Lawrence (given name), including a list of people with the name * Lawrence (surname), including a list of people with the name * Lawrence (band), an American soul-pop group * Lawrence (judge royal) (died after 1180), Hungarian nobleman, Judge royal 1164–1172 * Lawrence (musician), Lawrence Hayward (born 1961), British musician * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAGE Journals
SAGE Publishing, formerly SAGE Publications, is an American independent publishing company founded in 1965 in New York by Sara Miller McCune and now based in Newbury Park, California. It publishes more than 1,000 journals, more than 800 books a year, reference works and electronic products covering business, humanities, social sciences, science, technology and medicine. SAGE also owns and publishes under the imprints of Corwin Press (since 1990), CQ Press (since 2008), Learning Matters (since 2011), and Adam Matthew Digital (since 2012). History SAGE was founded in 1965 in New York City by Sara Miller (later Sara Miller McCune) with Macmillan Publishers executive George D. McCune as a mentor; the name of the company is an acronym formed from the first letters of their given names. SAGE relocated to Southern California in 1966, after Miller and McCune married; McCune left Macmillan to formally join the company at that time. Sara Miller McCune remained president for 18 years, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the physical or chemical structure of an organism's internal or external environment. The ability of an organism or organ to detect external stimuli, so that an appropriate reaction can be made, is called sensitivity (excitability). Sensory receptors can receive information from outside the body, as in touch receptors found in the skin or light receptors in the eye, as well as from inside the body, as in chemoreceptors and mechanoreceptors. When a stimulus is detected by a sensory receptor, it can elicit a reflex via stimulus transduction. An internal stimulus is often the first component of a homeostatic control system. External stimuli are capable of producing systemic responses throughout the body, as in the fight-or-flight response. In order for a stimulus to be detected with high probability, its level of strength must exceed the absolute threshold; if a signal does reach threshold, the information is transmitted to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autism Spectrum
The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulties in social interaction, verbal and nonverbal communication, and the presence of repetitive behavior and restricted interests. Other common signs include unusual responses to sensory stimuli. Autism is generally understood as a ''spectrum disorder'', which means that it can manifest differently in each person: any given autistic individual is likely to show some, but not all, of the characteristics associated with it, and the person may exhibit them to varying degrees. Some autistic people remain nonspeaking over the course of their lifespan, while others have relatively unimpaired spoken language. There is large variation in the level of support people require, and the same person may present differently at varying times. Historically, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hong Kong Journal Of Occupational Therapy
Hong may refer to: Places *Høng, a town in Denmark *Hong Kong, a city and a special administrative region in China *Hong, Nigeria *Hong River in China and Vietnam *Lake Hong in China Surnames *Hong (Chinese name) *Hong (Korean name) Organizations *Hong (business), general term for a 19th–20th century trading company based in Hong Kong, Macau or Canton *Hongmen (洪門), a Chinese fraternal organization Creatures *Hamsa (bird), a mythical bird also known was hong *Hong (rainbow-dragon) ''Hong'' or ''jiang'' () is a two-headed dragon in Chinese mythology, comparable with rainbow serpent legends in various cultures and mythologies. Chinese "rainbow" names Chinese has three "rainbow" words, regular ''hong'' , literary ''didong'' , ..., a two-headed dragon in Chinese mythology * ''Hong'' (genus), a genus of ladybird {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insomnia
Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, irritability, and a depressed mood. It may result in an increased risk of motor vehicle collisions, as well as problems focusing and learning. Insomnia can be short term, lasting for days or weeks, or long term, lasting more than a month. The concept of the word insomnia has two possibilities: insomnia disorder and insomnia symptoms, and many abstracts of randomized controlled trials and systematic reviews often underreport on which of these two possibilities the word insomnia refers to. Insomnia can occur independently or as a result of another problem. Conditions that can result in insomnia include psychological stress, chronic pain, heart failure, hyperthyroidism, heartburn, restless leg syndrome, menopause, certain medications, and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earplug
An earplug is a device that is inserted in the ear canal to protect the user's ears from loud noises, intrusion of water, foreign bodies, dust or excessive wind. Since they reduce the sound volume, earplugs are often used to help prevent hearing loss and tinnitus (ringing of the ears). History The first recorded mention of the use of earplugs is in the Greek tale ''Odyssey,'' wherein Odysseus's crew is warned about the Sirens that sing from an island they will sail past. Circe, their hostess, tells them of the Sirens' bewitching song that makes men drive their boats ashore and perish. She advised Odysseus to fashion earplugs for his men from beeswax so they would not be lured to their deaths by the sirens' song. In 1907, the German company Ohropax, which would produce mainly wax earplugs, was started by the German inventor Max Negwer. Ray and Cecilia Benner invented the first moldable pure silicone ear plug in 1962. These earplugs were valued by swimmers because of their waterpro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Class (aviation)
First class (also known as a suite) is a travel class on some passenger airliners intended to be more luxurious than business class, premium economy, and economy class. Originally all planes offered only one class of service (often equivalent to the modern business or economy class), with a second class appearing first in 1955, when TWA introduced two different types of service on its Super Constellations. On a passenger jetliner, ''first class'' usually refers to a limited number (rarely more than 10) of seats or cabins toward the front of the aircraft which have more space, comfort, service, and privacy. In general, first class is the highest class offered, although some airlines have either branded their new products as above first class or offering business class as the highest class. Propeller airliners often had first class in the rear, away from the noise of the engine and propeller, while first class on jet aircraft is normally positioned near the front of the airc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Business Class
Business class is a travel class available on many commercial airlines and rail lines, known by brand names which vary, by airline or rail company. In the airline industry, it was originally intended as an intermediate level of service between economy class and first class, but many airlines now offer business class as the highest level of service, having eliminated first-class seating. Business class is distinguished from other travel classes by the quality of seating, food, drinks, ground service and other amenities. In commercial aviation, full business class is usually denoted 'J' or 'C' with schedule flexibility, but can be many other letters depending on circumstances. Airlines History Airlines began separating full-fare and discounted economy-class passengers in the late 1970s. In 1976, KLM introduced a Full Fare Facilities (FFF) service for its full fare economy-class passengers, which allowed them to sit at the front of the economy cabin immediately behind first cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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