Sound Conductor Research Articles

ELECTROMECHANICAL PROGRAMMER FOR ACOUSTOELECTRONIC SENSORS OF PHYSICAL QUANTITIES

An electromechanical programmer is described, intended for programming an acoustoelectronic angular displacement meter, constructed on the basis of the effect of dependence of the phase velocity of surface acoustic waves on the direction of propagation relative to the crystallographic axis of a piezoelectric sound conductor.

Airborne noise calculation for single-layer partitions with the concentrated parameters method

The article considers an approach to the calculation of sound insulation for building partitions with the method of concentrated parameters at the standard frequency range, which is specified in regulatory documents. The concepts of “reduced” and “concentrated” masses are introduced for objects that are sound conductors. It is noted that the physical model of sound insulation in the three conditionally allocated frequency ranges of the standard spectrum has differences. The calculated equations of sound insulation for three frequency ranges are given. Systems of equations for obtaining the calculation formulas at the first and the second frequency ranges are used. The systems consist of equations for the conservation of the amount of motion and the conservation of kinetic energy. The influence of the damping effect of air and resonant phenomena in the plate on the final value of sound insulation is described. The nature of sound propagation in the third frequency range is considered, in which, unlike the first two sections of the frequency spectrum, where the propagation of flexural waves is mainly recorded in the plate, shear and dilatational vibrations have a predominant influence on the sound insulation level. Examples of graphs for massive partitions obtained by the considered method are given. The accuracy of the proposed method is evaluated in comparison with the normative code’s method and the method based on the theory of self-matching of sound fields. A general algorithm for calculating sound insulation in the entire standard frequency range is presented.

The Biophysical Function of the Human Middle Ear

The man perceives a part of the sounds with his organ of hearing which is of threefold setting up. The external ear is composed of the pavilion and the external auditory meatus (bore of hearing), then the middle ear (tympanum) sets up with the ear-drum membrane. In its cavity are to be found the auditory ossicles: the hammer (malleus), anvil (incus) and stapes, as sound conductors connecting the ear-drum with the oval window of the inner ear. Inside the oval window, the internal ear is filled up with fluid in which the balance-sensory organ (the semicircular canals) and the auditory organ, the cochlea take place. From here starts the auditory nerve to carry the stimulus of the cochlea to the auditory centre of our brain. It is our {auditory} organ of hearing to perceive speech and music. The evolution and continuous development of speech decisively contributed to the human race to emerge from the other living species, indeed, also the individual formation of speech essentially contributes to the explosion-like development of the child’s way of thinking.

Acoustic Properties of Innovative Concretes: A Review.

Concrete is the most common building material; therefore, when designing structures, it is obligatory to consider all structural parameters and design characteristics such as acoustic properties. In particular, this is to ensure comfortable living conditions for people in residential premises, including acoustic comfort. Different types of concrete behave differently as a sound conductor; especially dense mixtures are superior sound reflectors, and light ones are sound absorbers. It is found that the level of sound reflection in modified concrete is highly dependent on the type of aggregates, size and distribution of pores, and changes in concrete mix design constituents. The sound absorption of acoustic insulation concrete (AIC) can be improved by forming open pores in concrete matrices by either using a porous aggregate or foam agent. To this end, this article reviews the noise and sound transmission in buildings, types of acoustic insulating materials, and the AIC properties. This literature study also provides a critical review on the type of concretes, the acoustic insulation of buildings and their components, the assessment of sound insulation of structures, as well as synopsizes the research development trends to generate comprehensive insights into the potential applications of AIC as applicable material to mitigate noise pollution for increase productivity, health, and well-being.

ROLE OF KARNAPURANA KRIYA IN VARIOUS SYMPTOMS OF KARNAROGAS WITH SPECIAL REFERENCE TO CONTINUOUS USE OF HEADPHONES- A REVIEW

Background- Irrational use of electronic sound conductor as head phones, smart phones overuse causes sound pollution which affects the ear. In some extant Apathyakara Ahara Vihara also lead in development of different Karnarogas. Objectives- To analyses the role of KarnapuranaKriya in different karnarogas due to continuous use of headphones. Result and Discussion-Karnapuranakriya is better act on different symptoms of karnarogas like headache, vertigo, karnashushkta and karnanada. There are differenttailas are available in Ayurveda for karnapuranakriya like Tilataila, Sarshpataila, Bilvataila etc. These tailas are easily availableand cheap conservative line of treatment for different Karnarogas

To study the efficacy of Sarshapa Taila Karnapurana in Atiyoga of Karnendriya w.s.r. to continuous head phone users

Background: Irrational use of electronic sound conductor as head phones, smart phone overuse causes sound pollution which affects the ear. In some extent Apathyakara Ahara Vihara also leads in development of different types of Karnarogas. Objectives: To study the efficacy of Sarshapa Taila Karnapurana in Atiyoga of Karnendriya w.s.r. to continuous head phone users. Result and Discussion: Sarshap taila better acts on different symptoms of Atiyoga of Karnendriya like headache, vertigo, Karnashuskata and Karnanada. The percentage of relief was observed more in Sarshapa Taila compared to Tila Taila. This Taila is easily available and cheap conservative line of treatment for Atiyoga of Karnendriya.

Investigations on the heating effect of PE-LD induced by high-intensity focused ultrasound

High-intensity focused ultrasound is widely applied in tissue treatment as well as for heating of solid polymer materials. Previous studies investigating the heating effect in polymer materials utilized sound transmission through water or other fluids at low HIFU power. In this study, the ultrasonic transducer possesses a solid sound conductor made of aluminum and a high HIFU power of above 100W was applied to heat solid PE-LD samples. Temperature measurements were performed by calibrated non-invasive infrared thermal imaging. A strong heating effect with heating above melting temperature and evaporation temperature within less than 1s of irradiation was observed. Furthermore, the acoustic coupling defined by the force applied by the ultrasonic applicator to the polymer material was found to be fundamental to induce the heating effect. This investigation reveals HIFU for new applications in the field of polymer processing.

Protection against lightning overvoltages in resonant grounded power distribution networks

AES Sul, a Brazilian electric distribution utility, has recently started a project focused on the installation of neutral resonant grounding devices at the medium voltage side of some substation transformers previously operated with solid grounded neutral. As a consequence of the expected increase of the voltage in the sound conductors during phase to ground faults, all the surge arresters must be replaced with ones with increased rating. In order to minimize the number of required surge arresters, a procedure has been developed for the estimation of the annual number of lightning events causing concomitant faults in more than one phase conductor. The paper describes the procedure, which takes into account all the main factors that have a significant influence on line insulation flashovers caused by lightning, and presents results obtained for the case of an overhead line with and without protection means.

HEARING INSTRUMENT AND A METHOD OF OPERATING A HEARING INSTRUMENT

A hearing instrument in accordance with the invention comprises an in-the-ear-canal component to be worn at least partially in the ear of a user. When the hearing instrument is worn, a remaining volume between the in-the-ear-canal component and the user's eardrum is defined. The hearing instrument includes at least one first microphone operable to convert an acoustic input signal incident on the hearing instrument into an electrical input signal, signal processing means operable to convert the electrical input signal into an electrical output signal on a signal path, and an electrical-to-acoustic converter (a receiver or a plurality of receivers with potentially different frequency characteristics). Between the remaining volume and surrounding atmosphere, a duct (such as a vent) is defined. A second receiver is in operative communication with the duct, i.e. an output directly opens out into the duct or to a sound conductor opening out into the duct. The hearing instrument further comprises a second microphone in operative communication with said duct and operable to record an error signal in said duct.

Acral Lesions Examined by Water-immersed Ultrasonography

Background: The use of ultrasound in dermatology is widespread. However, difficulties in performing ultrasound on irregular surfaces have diminished its role in the diagnosis of acral lesions. We introduce a convenient method to examine acral lesions using water-immersed ultrasound. Materials and Methods: Utilizing water as a sound conductor, water-immersed ultrasonography was used to examine acral lesions, including inflammatory lesions, cysts and tumors. Results: Water-immersed ultrasonography is an easily manipulated method with excellent real-time images. Conclusion: Water-immersed ultrasonography is an excellent method for the examination of acral lesions.

The Radiation and Field Structure of a Short-Wave Acoustic Measuring Transducer

The main characteristics of a piezoelectric transducer and its ultrasonic field in sound conductors and the monitored medium are considered, as they apply to systems and instruments for acoustic measurements of the parameters of technological processes. Formulas are obtained for determining the radiation pressure and its distribution in the transducer field.

Оn thе influence оf acoustic attenuation in thе transducer layers under thе excitation оf thе volume elastic waves by 6mm class piezoelectric with arbitrary orientation of axis 6

An electroacoustic transducer оn the bases оf the piezoelectric class 6mm with axis 6 arbitrary orientation with electrodes of final thickness regarding the acoustic attenuation in its layers is considered. The system оf equations for the computation the transducer impedance, longitudinal and shear wave radiation resistance, power ratio of these waves in the sound conductor, and also the conversion losses for longitudinal and shear waves is obtained. The numerical analysis results of attenuation effect in the specific transducer in the range of 15 GHz are given.

An excitation of surface acoustic waves in the ear canal

Usually electrodynamic loudspeakers have a small flexibility of the diaphragm. Therefore, at sound reproduction of low frequencies, a coupling space between the diaphragm and the ear must be hermetic. In a range of high frequencies, distortions are stipulated by the presence of reflected sound waves, and depend on the ear canal’s position in the closed sound space. There is a coupled acoustic resonant system which consists of the pinna, the eardrum, and the ear canal. Sound oscillations excited in a cartilaginous part of the outer ear are partly reflected, but an absorbed component is spread through subcutaneous conjunctive tissue toward an attachment place of the tympanic membrane via surface acoustic waves (SAW). The hearing thresholds’ data received by use of a special sound conductor which is generating SAW, in a range of frequencies 125–8000 Hz, did not show statistic distinctions regarding measurings carried out via conventional tonal audiometry. It is supposed that mechanical energy necessary for excitation of auditory sensation with the help of oscillations spreading through the conjunctive tissue of the ear canal is required even less than at the creation of equivalent levels of air pressure because an amplitude of acoustic oscillations is directly attached to the eardrum edge.

Acoustic properties of the normal chest.

Laënnec invented the stethoscope in 1816 and published a treatise on auscultation in 1819. We then had to wait until the 1950s to observe development of modern devices and methods of recording and signal-processing, which allowed objective studies of lung sounds in time and frequency fields. Tracheobronchial sounds generated by ventilation originate in the upper airways, the frequency content of these sounds has led to extensive research. Consolidated lungs act as more efficient sound conductors to the chest wall (bronchial breathing murmur). Tracheobronchial sounds contain higher frequency components compared to vesicular lung sounds. The origin of vesicular lung sounds has been becoming progressively clear for about 10 yrs. It is at least partly produced locally, deep, and probably intralobular. Clearly, further studies need to be performed in order to elucidate the true mechanisms involved in generating vesicular lung sounds, the redistribution of intrapulmonary gas or vibrations caused by the stretching of lung tissue. The devices developed are already useful for monitoring the state of patients in intensive care. Sooner or later, real time analysis and automated diagnosis will become available.

Experimental investigations on intracavity sonography. Part 1: Alteration of imaging by variation of the contents of rigid hollow receptacles or isolated porcine urinary bladders.

Multiple artifacts may occur in the diagnostic application of sonography. Occasionally, these may make it difficult to differentiate real tissue structures. In order to investigate the imaging properties of ultrasound in intracavity investigation techniques, we have examined the imaging under different conditions in rigid hollow receptacles as well as in an isolated porcine urinary bladder. A measurable difference of sound conduction depended on the characteristics of the fluid (sound conductor): furthermore, accumulation of air in the hollow space lead to various interfering echos. The importance of a central position of a sound source for obtaining useful sonograms in intracavity ultrasonographic diagnosis was evident.

Diagnosis of mandibular fractures by auscultation with percussion

The auscultation-percussion diagnostic test for fractures of the mandible is presented. The presence of a fracture of the mandible can be determined by its properties as a sound conductor. A stethoscope is placed firmly over the symphysis, and then the areas over the right and left zygomas, condyles, and angles are struck lightly with a finger. The sound of the blow is conducted downward through the bony substance of the mandible. Since transmission of sound through dense bone is more efficient than through less dense soft tissue, any break in the bony column will result in a decrease in the transmission of the sound. Comment is made on the simplicity and value of this diagnostic aid. The factors involved in its execution are discussed.

Construction Material of the Sound Conduction System of the Human Ear

The behavior of the living elastic bodies in the ear must be studied for a full understanding of the ear as sound conductor. Two elementary structural elements possessing restoring forces are the collagen fiber and the elastic fiber. These two tissue elements form membranes, ligaments, tendons, and articulations in the ear. The physical behavior of these two fiber systems is described. Three areas in the ear are distinguished according to their construction material. Methods of measuring the physical characteristics of the ear structures are described. The linear displacement of the center of the ear drum as a function of static pressure changes in the outer ear canal is given. Static movements of the stapes footplate due to reflectoric muscle contractions were used to calculate the elongation of the stapes ringband in vivo.

Tinnitus and Other Subjective Phenomena—and the Hearing Process

Disease, intoxications and injuries cause subjective phenomena of hearing that shed much light on the mechanism of hearing, and on the causes of deafness. Paralysis of the tensor tympani muscle arising from injury to the fifth cranial nerve causes dysakusia for low frequencies—a condition in which high intensities produce discomfort or actual pain. Hyperacousis, or increased acuteness of hearing, in which the loudness of sound is accentuated, follows injuries to the facial nerve paralyzing the stapedius muscle. Affections of these middle ear muscles by myasthenia gravis, or other diseases which give rise to muscular fibrillations, cause roaring, “boiler factory” tinnitus. In the absence of the ear drum, high intensities of low frequencies cause vertigo and falling. These phenomena parallel in many respects animal experimental findings such as those reported by Drs. Wever and Bray; and indicate that the middle ear mechanism serves primarily as a sound impedance that protects the inner ear, rather than as a specialized sound conductor. Tinnitus of inner ear origin may be caused either by anemia, congestion, allergy or spasm of blood vessels. Intoxication by quinine, aspirin and other salicylates, and ergot are among the most frequent causes of these types of tinnitus and deafness. They act by causing spasm of the blood vessels. The incidence of progressive deafness could be considerably reduced by restriction of these drugs. Increased pressure of the perilymph on the inner ear gives rise to tinnitus which is readily cleared up by spinal tap and by medical therapy designed to keep the pressure down. Hallucinations of hearing often characterize disease of the brain involving the central nervous mechanism of hearing.