Accoustics

This is an exploration of a type of chanting that is not ordinarily considered music, but through “musical” parameters such as pitch, vocal style and intensity, it is often performed in settings in a musical way in order to create a vocal soundscape that surpasses that of everyday speech, although is distant from the singing voice in terms of its context and style of performance. This paper draws on Schafer’s work on soundscape in order to explore the ways the voice forms part of a meaningful sound environment (e.g., 1977, 1992, 1993). A performer who uses chanting, or a vocal style very close to this creates its soundscapes, or “voicescapes”, in order to position it within a particular social situation and context to command a position of intense affect. This exploration of the socially performed voice shows that in some contexts it clearly has musical traits—something that challenges the boundaries of what music is or is not—and that social performance is an important process allowing such vocal performances to carry meaning. The discussion presents several examples of the chanting voice as a performing instrument that is essential to many contexts of everyday life. It is an instrument that creates voicescapes in a multitude of social settings in order to, for example, capture the attention of listeners, add expression to a situation, or position the chanter vis-à-vis an audience. The contexts in which such vocal performances are found include auctions, horse races, sports commentaries, marches, and markets. In such contexts the voice is performed in a chant-like way in order to capture the attention of an audience or to express in an emotional way a scene or image. In each, the voice is usually raised in pitch, in intensity, and it chants.

Vibration damped very widely applied in daily life, for
example  in  suspense  on a variety  of vehicles  that utilize  the
vibration  damping.  Damped  vibration  itself  can be divided
into  less vibration damped  (underdamped),  critically damped
vibration  (critical  damped),  and  excessive  vibration  damped
(Over damped). In this report adakn do a calculated damping
ratio  on  sistempegas  with  different  damping,  to  be able to
know the kind of muffled vibrations that occur in the system.

Keywords: Vibrations, Damped Vibration, Damping Ratio

Among the problems associated with technological advancement made by man in modern times which is not receiving enough attention from those responsible for the planning and designing of the built environment is noise pollution. Noise, an unwanted and irritating sound, is a form of environmental pollution and a source of stress. Loud noise is harmful and impacts negatively on the quality of the built environment. This paper, therefore, seeks to identify the major sources of noise and its impact in the built environment of a typical housing estate in Akure, the capital of Ondo State. The paper adopted a survey research method. It relied on the data collected from a survey carried out on some of the buildings along the major streets in Oba-Ile Housing Estate, Akure, Nigeria. It was observed that noises from vehicular traffic, pedestrian traffic and religious buildings, as the major sources of external noise, have very serious negative effects on the residents. Generating sets, telephone/mobile phones, radio and television sets constitute the major sources of internal noise with very serious negative effects on the residents of the study area. It recommends good design and building orientation, adequate set back, reduction in the opening sizes and reduction of noise from sources as some of the ways to minimise the problems of noise pollution in built environment.

The Universe is full of vibration and contains sound. We know nowadays that these vibrations range from the acoustic waves of the Cosmic Microwave Background (CMB) to the influence of planetary aurorae captured by space probes.
This fact was proposed as an hypothesis by Pythagoras of Samos, mathematician, philosopher, astronomer and musician of the Antiquity. It is Aristotle who, in “On the Pythagoreans”, transmits his “Music of the Spheres” theory. In the subjective part of his Cosmogony, Pythagoras seems to have included hypotheses on the soul and metempsychosis.
Since the XXth century we know that stars form from clouds of interstellar gas, the star formation is governed by acoustic waves. We know nowadays that the study of the acoustic waves of the Cosmic Microwave Background shows us an infinite expansion of the Universe, a dilution of matter.

An acoustic one-dimensional compressor model has been developed. This model is based on compressor map information and it is able to predict how the pressure waves are transmitted and reflected by the compressor. This is later on necessary to predict radiated noise at the intake orifice. The fluid-dynamic behavior of the compressor has been reproduced by simplifying the real geometry in zero-dimensional and one-dimensional elements with acoustic purposes. These elements are responsible for attenuating or reflecting the pressure pulses generated by the engine. In order to compensate the effect of these elements in the mean flow variables, the model uses a corrected compressor map. Despite of the fact that the compressor model was developed originally as a part of the OpenWAM™ software, it can be exported to other commercial wave action models. An example is provided of exporting the described model to GT-Power™. The model has been validated using experimental results obtained in a turbocharger test bench under pulsating flow conditions. The characteristics of the pressure waves (amplitude, frequency and mean flow) are similar to those of the pulses that the compressor undergoes when working coupled to a reciprocating internal combustion engine. This facility allows wave decomposition upstream and downstream of the compressor. The experimental pressure waves have been compared versus the results provided by the model analyzing both in frequency domain and in time domain in the two codes used to host the model. Finally, a comparison between the proposed 1D-0D model, which furthermore applies the compressor map, and the standard methodology used by GT-Power™, which directly only interpolates in the compressor map, has been performed. Results show better performance in the case of the proposed model and evidence the interest for the compressor geometrical description.

The article presents the function of acoustic patterns (Szilágyi 2004) in analogical linguistic processes. Analyzing the common features of Hungarian onomatopoetic verb groups’ phonetic structure, the author considers that the described acoustic patterns function as a background
for lexical and morphological analogy. Certain aspects of lexicalization and some processes of integration of borrowed words can be explained by the influence of these acoustic patterns.

Bubbles confined in microchannels self-organize without directly contacting one another when excited by an external acoustic field. The bubbles tend to form periodic "crystal"-like lattices with a finite interbubble distance. This equilibrium distance can be adjusted by simply tuning the acoustic frequency. This new type of crystal is purely mediated by acoustic surface waves emitted by the pulsating bubbles. Because these waves are reflected at the channel boundaries, the bubbles interact with their own images across the boundary.

Sound is composed of both compression and expansion waves. Here we present an experimental setup of an aerophone which produces a continous compression wave of very high intensity and with wavelength of over 1 kilometer. This wave can compress air, water and soil in nature, assuring a better cohesion for them. Using the template The pneumatic siren consists of a rotating disk with holes in it, the rotor, so that the material between the holes interrupts the flow of air from the holes of another immobile disk named stator, to the outside of the machine 1. The first pneumatic siren was invented by Baron Charles Cagniard de la Tour 2. As the holes in the rotor alternately prevent and allow air flow, this process results in alternating compressions and expansions of air, producing sounds 3. Sound frequency is given by the frequency of rotation of the rotor. Such a siren consumes large amounts of energy, but this consumption can be reduced without loss of sound quality if the pneumatic siren is power-fed by forcing compressed air from a tank, the tank being refueled by a compressor with low consumption energy. A pneumatic siren can also be powered by an electric motor. Unlike the normal pneumatic siren, the source of cohesion waves does not have holes in the stator, even if it has holes in the rotor. The usual pneumatic siren emits sounds consisting of alternative compressions and expansions of air with moderate intensities, as shown in Fig. 1. Figure SEQ Figure \* ARABIC 1. The structure of sound. Materials and methods The cohesion waves source is a modified version of the pneumatic siren which emits a compression pulse of high intensity and high wavelength on the order of hundreds of kilometers, at a range of low enough frequencies so that energy is not dissipated by friction forces of transmission media, as shown in Fig. 2.

Fibre reinforced polymer (FRP) components can have visible or non-visible damages because of an impact, crush, or fatigue during the regular operation hours. These components or structures have to be continuously monitored in order to ensure an early detection of deterioration. This paper uses the vibration decay rate experimentally as a method to detect damages in a FRP component. Measurement of reverberation time RT 60 is executed in three different damage conditions of a specimen made of fibre reinforced polymer. The conditions of the specimen vary based on the damage existence in it. The major concern is on predicting damages presence by the measured data. The resulted data showed a clear difference among the three conditions proving the damages existence.

Little work has been done on the localization of microcracks in bone using acoustic emission. Microcrack localization is useful to study the fracture process in bone and to prevent fractures in patients. Locating microcracks that occur before fracture allows one to predict where fracture will occur if continued stress is applied to the bone. Two source location algorithms were developed to locate microcracks on rectangular bovine bone samples. The first algorithm uses a constant velocity approach which has some difficulty dealing with the anisotropic nature of bone. However, the second algorithm uses an iterative technique to estimate the correct velocity for the acoustic emission source location being located. In tests with simulated microcracks, the constant velocity algorithm achieves a median error of 1.78 mm (IQR 1.51 mm) and the variable velocity algorithm improves this to a median error of 0.70 mm (IQR 0.79 mm). An experiment in which the bone samples were loaded in a three point bend test until they fractured showed a good correlation between the computed location of detected microcracks and where the final fracture occurred. Microcracks can be located on bovine bone samples using acoustic emission with good accuracy and precision.