⭐⭐⭐⭐⭐ How Do Sound Waves Affect Human Hearing

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How Do Sound Waves Affect Human Hearing



The components of essential oils are classified into two major groups terpenes and aromatic compounds based on their biosynthetic origin. Adults Although many diseases and Everlasting Ivy Character Analysis can induce hearing loss, relatively How Do Sound Waves Affect Human Hearing result in profound sensorineural deafness. Investigate How Do Sound Waves Affect Human Hearing Animals How is sound used How Do Sound Waves Affect Human Hearing study marine mammal distribution? Holmes C. Pomerantz eds. A formal hearing testing can give a more exact measure of hearing.

Sound: Crash Course Physics #18

Ultrasound inspection of welded joints has been an alternative to radiography for nondestructive testing since the s. Ultrasonic inspection eliminates the use of ionizing radiation, with safety and cost benefits. Ultrasound can also provide additional information such as the depth of flaws in a welded joint. Ultrasonic inspection has progressed from manual methods to computerized systems that automate much of the process. An ultrasonic test of a joint can identify the existence of flaws, measure their size, and identify their location. Not all welded materials are equally amenable to ultrasonic inspection; some materials have a large grain size that produces a high level of background noise in measurements. Ultrasonic thickness measurement is one technique used to monitor quality of welds.

A common use of ultrasound is in underwater range finding ; this use is also called Sonar. An ultrasonic pulse is generated in a particular direction. If there is an object in the path of this pulse, part or all of the pulse will be reflected back to the transmitter as an echo and can be detected through the receiver path. By measuring the difference in time between the pulse being transmitted and the echo being received, it is possible to determine the distance. The measured travel time of Sonar pulses in water is strongly dependent on the temperature and the salinity of the water.

Ultrasonic ranging is also applied for measurement in air and for short distances. For example, hand-held ultrasonic measuring tools can rapidly measure the layout of rooms. Although range finding underwater is performed at both sub-audible and audible frequencies for great distances 1 to several kilometers , ultrasonic range finding is used when distances are shorter and the accuracy of the distance measurement is desired to be finer.

Ultrasonic measurements may be limited through barrier layers with large salinity, temperature or vortex differentials. Ranging in water varies from about hundreds to thousands of meters, but can be performed with centimeters to meters accuracy. The potential for ultrasonic imaging of objects, with a 3 GHz sound wave producing resolution comparable to an optical image, was recognized by Sokolov in , but techniques of the time produced relatively low-contrast images with poor sensitivity. The power density is generally less than 1 watt per square centimetre to avoid heating and cavitation effects in the object under examination. Ultrasonic imaging applications include industrial nondestructive testing, quality control and medical uses.

Acoustic microscopy is the technique of using sound waves to visualize structures too small to be resolved by the human eye. Frequencies up to several gigahertz are used in acoustic microscopes. The reflection and diffraction of sound waves from microscopic structures can yield information not available with light. Medical ultrasound is an ultrasound-based diagnostic medical imaging technique used to visualize muscles, tendons, and many internal organs to capture their size, structure and any pathological lesions with real time tomographic images. Ultrasound has been used by radiologists and sonographers to image the human body for at least 50 years and has become a widely used diagnostic tool.

The technology is relatively inexpensive and portable, especially when compared with other techniques, such as magnetic resonance imaging MRI and computed tomography CT. Ultrasound is also used to visualize fetuses during routine and emergency prenatal care. Such diagnostic applications used during pregnancy are referred to as obstetric sonography. As currently applied in the medical field, properly performed ultrasound poses no known risks to the patient. Ultrasound is also increasingly being used in trauma and first aid cases, with emergency ultrasound becoming a staple of most EMT response teams. Furthermore, ultrasound is used in remote diagnosis cases where teleconsultation is required, such as scientific experiments in space or mobile sports team diagnosis.

According to RadiologyInfo, [32] ultrasounds are useful in the detection of pelvic abnormalities and can involve techniques known as abdominal transabdominal ultrasound, vaginal transvaginal or endovaginal ultrasound in women, and also rectal transrectal ultrasound in men. Diagnostic ultrasound is used externally in horses for evaluation of soft tissue and tendon injuries, and internally in particular for reproductive work — evaluation of the reproductive tract of the mare and pregnancy detection.

By , ultrasound technology began to be used by the beef cattle industry to improve animal health and the yield of cattle operations. Ultrasound technology provides a means for cattle producers to obtain information that can be used to improve the breeding and husbandry of cattle. The technology can be expensive, and it requires a substantial time commitment for continuous data collection and operator training. High-power applications of ultrasound often use frequencies between 20 kHz and a few hundred kHz. Intensities can be very high; above 10 watts per square centimeter, cavitation can be inducted in liquid media, and some applications use up to watts per square centimeter.

Such high intensities can induce chemical changes or produce significant effects by direct mechanical action, and can inactivate harmful microorganisms. Ultrasound has been used since the s by physical and occupational therapists for treating connective tissue : ligaments , tendons , and fascia and also scar tissue. Ultrasound also has therapeutic applications, which can be highly beneficial when used with dosage precautions. Ultrasonic impact treatment UIT uses ultrasound to enhance the mechanical and physical properties of metals. Ultrasonic treatment can result in controlled residual compressive stress, grain refinement and grain size reduction.

Low and high cycle fatigue are enhanced and have been documented to provide increases up to ten times greater than non-UIT specimens. Additionally, UIT has proven effective in addressing stress corrosion cracking , corrosion fatigue and related issues. When the UIT tool, made up of the ultrasonic transducer, pins and other components, comes into contact with the work piece it acoustically couples with the work piece, creating harmonic resonance.

Depending on the desired effects of treatment a combination of different frequencies and displacement amplitude is applied. UIT devices rely on magnetostrictive transducers. Ultrasonication offers great potential in the processing of liquids and slurries, by improving the mixing and chemical reactions in various applications and industries. Ultrasonication generates alternating low-pressure and high-pressure waves in liquids, leading to the formation and violent collapse of small vacuum bubbles. This phenomenon is termed cavitation and causes high speed impinging liquid jets and strong hydrodynamic shear-forces. These effects are used for the deagglomeration and milling of micrometre and nanometre-size materials as well as for the disintegration of cells or the mixing of reactants.

In this aspect, ultrasonication is an alternative to high-speed mixers and agitator bead mills. Ultrasonic foils under the moving wire in a paper machine will use the shock waves from the imploding bubbles to distribute the cellulose fibres more uniformly in the produced paper web, which will make a stronger paper with more even surfaces. Furthermore, chemical reactions benefit from the free radicals created by the cavitation as well as from the energy input and the material transfer through boundary layers.

For many processes, this sonochemical see sonochemistry effect leads to a substantial reduction in the reaction time, like in the transesterification of oil into biodiesel. Substantial ultrasonic intensity and high ultrasonic vibration amplitudes are required for many processing applications, such as nano-crystallization, nano-emulsification, [42] deagglomeration, extraction, cell disruption, as well as many others. Commonly, a process is first tested on a laboratory scale to prove feasibility and establish some of the required ultrasonic exposure parameters. After this phase is complete, the process is transferred to a pilot bench scale for flow-through pre-production optimization and then to an industrial scale for continuous production.

During these scale-up steps, it is essential to make sure that all local exposure conditions ultrasonic amplitude, cavitation intensity, time spent in the active cavitation zone, etc. If this condition is met, the quality of the final product remains at the optimized level, while the productivity is increased by a predictable "scale-up factor". The productivity increase results from the fact that laboratory, bench and industrial-scale ultrasonic processor systems incorporate progressively larger ultrasonic horns , able to generate progressively larger high-intensity cavitation zones and, therefore, to process more material per unit of time.

This is called "direct scalability". It is important to point out that increasing the power of the ultrasonic processor alone does not result in direct scalability, since it may be and frequently is accompanied by a reduction in the ultrasonic amplitude and cavitation intensity. During direct scale-up, all processing conditions must be maintained, while the power rating of the equipment is increased in order to enable the operation of a larger ultrasonic horn. A researcher at the Industrial Materials Research Institute, Alessandro Malutta, devised an experiment that demonstrated the trapping action of ultrasonic standing waves on wood pulp fibers diluted in water and their parallel orienting into the equidistant pressure planes.

This could provide the paper industry a quick on-line fiber size measurement system. A somewhat different implementation was demonstrated at Pennsylvania State University using a microchip which generated a pair of perpendicular standing surface acoustic waves allowing to position particles equidistant to each other on a grid. This experiment, called acoustic tweezers , can be used for applications in material sciences, biology, physics, chemistry and nanotechnology. Ultrasonic cleaners , sometimes mistakenly called supersonic cleaners , are used at frequencies from 20 to 40 kHz for jewellery , lenses and other optical parts, watches , dental instruments , surgical instruments , diving regulators and industrial parts.

An ultrasonic cleaner works mostly by energy released from the collapse of millions of microscopic cavitations near the dirty surface. The bubbles made by cavitation collapse forming tiny jets directed at the surface. Similar to ultrasonic cleaning, biological cells including bacteria can be disintegrated. High power ultrasound produces cavitation that facilitates particle disintegration or reactions. This has uses in biological science for analytical or chemical purposes sonication and sonoporation and in killing bacteria in sewage. High power ultrasound can disintegrate corn slurry and enhance liquefaction and saccharification for higher ethanol yield in dry corn milling plants.

The ultrasonic humidifier, one type of nebulizer a device that creates a very fine spray , is a popular type of humidifier. It works by vibrating a metal plate at ultrasonic frequencies to nebulize sometimes incorrectly called "atomize" the water. Because the water is not heated for evaporation, it produces a cool mist. The ultrasonic pressure waves nebulize not only the water but also materials in the water including calcium, other minerals, viruses, fungi, bacteria, [49] and other impurities.

Illness caused by impurities that reside in a humidifier's reservoir fall under the heading of "Humidifier Fever". Ultrasonic humidifiers are frequently used in aeroponics , where they are generally referred to as foggers. In ultrasonic welding of plastics, high frequency 15 kHz to 40 kHz low amplitude vibration is used to create heat by way of friction between the materials to be joined.

The interface of the two parts is specially designed to concentrate the energy for maximum weld strength. Compared to humans, the Heffners concluded whitetailed deer have better high-frequency hearing but poorer low-frequency hearing. Invented in Austria in , deer whistles are still distributed by many companies in Europe and the United States. The devices are generally attached to the front of the vehicle, and manufacturers claim they produce ultrasonic frequencies and warn animals of approaching vehicles, thereby reducing deer-vehicle collisions.

Early tests conducted in Finland indicated that canids, bears, deer and elk heard sounds emitted by the whistles because their ears moved. However, other investigators found the testing procedures were faulty. In Utah, researchers Laura Romin and Larry Dalton detected no differences in responses from groups of free-ranging mule deer to vehicles equipped with and without deer whistles. Although some deer ran away from the test vehicle, they did so regardless of the presence or absence of whistles.

Apparently, some commercially available deer whistles do not produce sound of ultrasonic frequency, as claimed. In fact, some emit no sound at all under normal operating conditions. These so-called pure tones can also be produced using standard sound equipment. For this reason, Valitzski and her group tested the effectiveness of a range of pure-tone sounds for altering the behavior of whitetails along roadways for prevention of deer-vehicle collisions. The study was conducted during April and June at the Berry College Wildlife refuge, located in northwestern Georgia, in an area with about deer per square mile.

The Georgia-based researchers equipped a test vehicle with four high-frequency speakers calibrated to deliver selected frequencies between. Speakers were set to emit sounds directly in front of the vehicle as well as to the sides. Levels of sound intensity were set high enough 70 decibels to ensure that deer could hear the transmitted sounds, above vehicle road noise, within 10 meters Two test areas were established and marked with a study area of influence, encompassing a roadway and a meter buffer zone on either side. During each test, an observer recorded deer behavior in response to one of six randomly selected treatments, including five different frequencies produced by the vehicle-mounted sound system as well as a control no sound , as the vehicle was driven about 30 mph through the test area.

Each trial was conducted either at dawn or dusk to maximize deer sightings, and only under ideal weather conditions to ensure the sound carried properly. Behavior of selected i. The observers then scored changes in behavior as follows:. Negative interaction — deer response likely to cause a deer-vehicle accident; 2. Even though a small section of the wave form from each instrument looks very similar see the expanded sections indicated by the orange arrows in figure 4 , differences in changes over time between the clarinet and the piano are evident in both loudness and harmonic content. Less noticeable are the different noises heard, such as air hisses for the clarinet and hammer strikes for the piano. Sonic texture relates to the number of sound sources and the interaction between them.

Spatial location see: Sound localization represents the cognitive placement of a sound in an environmental context; including the placement of a sound on both the horizontal and vertical plane, the distance from the sound source and the characteristics of the sonic environment. This is the main reason why we can pick the sound of an oboe in an orchestra and the words of a single person at a cocktail party. Ultrasound is sound waves with frequencies higher than 20, Hz or 20 kHz. Ultrasound is not different from "normal" audible sound in its physical properties, except in that humans cannot hear it. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.

Ultrasound is commonly used for medical diagnostics such as sonograms. Infrasound is sound waves with frequencies lower than 20 Hz. Although sounds of such low frequency are too low for humans to hear, whales, elephants and other animals can detect infrasound and use it to communicate. It can be used to detect volcanic eruptions and is used in some types of music. From Wikipedia, the free encyclopedia. This article is about audible acoustic waves. For other uses, see Sound disambiguation. Vibration that propagates as an acoustic wave. Main article: Acoustics. Play media. Longitudinal and transverse plane wave. Main article: Speed of sound. See also: Perception of infrasound. Western Electrical Company.

American National Standard: Acoustic Terminology. Sec 3. Archived from the original on 14 May Retrieved 22 May Archived from the original on 30 April Retrieved 26 June Archived at the Wayback Machine Northwestern University. Beginner Archived at the Wayback Machine. Cornell University. Archived from the original on 10 April Retrieved 9 April Timbre perception and auditory object identification Archived at the Wayback Machine. Hearing, — The role of acoustic signal partitions in listener categorization of musical phrases. Music Perception, — Introduction to timbre. Cook Ed. Astronomy Picture of the Day. Archived from the original on Retrieved Science Advances. Bibcode : SciA PMC PMID In Webster's Collegiate Dictionary Fifth ed.

Cambridge, Mass. Autor Music, Physics and Engineering. Dover Publications. ISBN Houghton Mifflin Company. Archived from the original on June 25, Retrieved May 20, The elements of music: what are they, and who cares? Archived at the Wayback Machine In J. ISSN Journal of the Association for Research in Otolaryngology. Pitch perception models. Pitch, Cerebral Cortex. Electroencephalography and Clinical Neurophysiology.

The study Hospice Coverage: A Case Study conducted during How Do Sound Waves Affect Human Hearing and June How Do Sound Waves Affect Human Hearing the Berry College Wildlife refuge, located in northwestern Georgia, in an area with about deer per square mile. Electroencephalography: Basic Principles Mausoleum Terracotta Analysis Applications. Furthermore, the temporal characteristics of experienced sounds suggest that sounds are not simple How Do Sound Waves Affect Human Hearing.

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