❤️
The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, or yelling. The human voice frequency is specifically a part of human sound production in which the vocal folds (vocal cords) are the primary sound source. (Other sound production mechanisms produced from the same general area of the body involve the production of unvoiced consonants, clicks, whistling and whispering.)
Generally speaking, the mechanism for generating the human voice can be subdivided into three parts; the lungs, the vocal folds within the larynx (voice box), and the articulators. The lungs, the "pump" must produce adequate airflow and air pressure to vibrate vocal folds. The vocal folds (vocal cords) then vibrate to use airflow from the lungs to create audible pulses that form the laryngeal sound source. The muscles of the larynx adjust the length and tension of the vocal folds to 'fine-tune' pitch and tone.
even the smallest amount of something spoken or written.
noun: a word
word; plural noun: words
A harmonic is any member of the harmonic series. The term is employed in various disciplines, including music, physics, acoustics, electronic power transmission, radio technology, and other fields. It is typically applied to repeating signals, such as sinusoidal waves.
say
/seɪ/
verb: say; 3rd person present: says; past tense: said; past participle: said; gerund or present participle: saying
1.
utter words so as to convey information, an opinion, a feeling or intention, or an instruction.
"‘Thank you,’ he said"
All my heart. 🙏🏻❤️
Pyramidal horn (a, right) – a horn antenna with the horn in the shape of a four-sided pyramid, with a rectangular cross section. They are a common type, used with rectangular waveguides, and radiate linearly polarized radio waves. ... These types are often used as feed horns for wide search radar antennas.
The first modern horn antenna in 1938 with inventor Wilmer L. Barrow.
They are used as feed antennas (called feed horns) for larger antenna structures such as parabolic antennas, as standard calibration antennas to measure the gain of other antennas, and as directive antennas for such devices as radar guns, automatic door openers, and microwave radiometers. Their advantages are moderate directivity, low standing wave ratio (SWR), broad bandwidth, and simple construction and adjustment.
A horn antenna is used to transmit radio waves from a waveguide (a metal pipe used to carry radio waves) out into space
the physical universe beyond the earth's atmosphere.
noun: outer space; plural noun: outer spaces
outer space
deep space
the universe
the cosmos
the galaxy
the solar system
infinity
the near-vacuum extending between the planets and stars, containing small amounts of gas and dust.
Phased array antennas have attracted much attention in recent years because of their appealing capabilities to realize a variety of unique radiation characteristics such as high gain, low sidelobe levels, beam scanning, and null steering. The radiation characteristics mainly depend upon the element pattern, the excitation amplitude and phase, inter-element spacing, as well as the array geometry1,2. A number of well-defined techniques, namely the Taylor and Dolph–Chebyschev methods1,2,3,4, use tapered amplitude excitation on uniformly-spaced array antennas to reduce and control the sidelobe levels. Low sidelobe levels can also be achieved by optimizing the phase shifts of the uniformly-spaced array elements5.
In 1961, Harrington6 proposed a novel technique of reducing the sidelobe levels of array antennas with uniform excitation by employing the method of non-uniform spacing of array elements. This technique was further investigated to design unequally-spaced array antennas with uniform6,7,8,9 as well as non-uniform excitation10,11 to improve the array performance, compared to uniformly spaced arrays12,13,14,15. It was demonstrated that the radiation characteristics, e.g., the position of the nulls, beamwidth, sidelobe levels, of the non-uniform arrays can be controlled by the location, magnitude and phase of their base elements. A vast variety of evolutionary algorithms such as genetic algorithm (GA), particle swarm optimization (PSO), and differential evolution (DE), were developed for the purpose of optimizing the element positions and excitation to reduce the computational cost16,17,18,19.
This has led to the development of antenna arrays, realizing narrow beamwidths, null steering and reduced sidelobe levels by controlling the element position and excitation20,21,22,23. However, in order to achieve different desired radiation characteristics, it is required that the base element be physically displaced to a pre-determined position. As the element position varies per the requirement, the practical implementation becomes costly and complex. Therefore, a new research paradigm is needed to realize adaptive element spacing arrays over the course of the operation.
infinity
hold on...
An ultrasonic horn (also known as acoustic horn, sonotrode, acoustic waveguide, ultrasonic probe) is a tapering metal bar commonly used for augmenting the oscillation displacement amplitude provided by an ultrasonic transducer operating at the low end of the ultrasonic frequency spectrum (commonly between 15 and 100 kHz). The device is necessary because the amplitudes provided by the transducers themselves are insufficient for most practical applications of power ultrasound.[2]
Another function of the ultrasonic horn is to efficiently transfer the acoustic energy from the ultrasonic transducer into the treated media,[3] which may be solid (for example, in ultrasonic welding, ultrasonic cutting or ultrasonic soldering) or liquid (for example, in ultrasonic homogenization, sonochemistry, milling, emulsification, spraying or cell disruption).[1] Ultrasonic processing of liquids relies of intense shear forces and extreme local conditions (temperatures up to 5000 K and pressures up to 1000 atm) generated by acoustic cavitation.[2]
Acoustic cavitation is the formation and collapse of bubbles in liquid irradiated by intense ultrasound. The speed of the bubble collapse sometimes reaches the sound velocity in the liquid. Accordingly, the bubble collapse becomes a quasi-adiabatic process. ... The pulsation of active bubbles is intrinsically nonlinear.
Recently retired, no longer affiliated with any party. Constitutional patriot listening for God’s word
Cleaning by sound waves
The most well known, and the first piezoelectric material used in electronic devices is the quartz crystal. Other naturally occurring piezoelectric materials include cane sugar, Rochelle salt, topaz, tourmaline, and even bone.
Piezoelectricity is a phenomenon of strain induced electric polarization in certain crystals, which can be used to create a mechanical action by applying an external voltage for sensors and actuators, or an mechanical straining can produce a voltage for energy conversion.
Plasma (from Ancient Greek πλάσμα 'moldable substance') is one of the four fundamental states of matter. It consists of a gas of ions – atoms or molecules which have at least one orbital electron stripped (or an extra electron attached) and, thus, an electric charge.
Sonoluminescence is the emission of light from imploding bubbles in a liquid when excited by sound.
In virology. In 1935 tobacco mosaic virus became the first virus to be crystallized; in 1955 the poliomyelitis virus was crystallized
The positive influence of ultrasound (US) on crystallization processes is shown by the dramatic reduction of the induction period, supersaturation conditions and metastable zone width. Manipulation of this influence can be achieved by changing US-related variables such as frequency, intensity, power and even geometrical characteristics of the ultrasonic device (e.g. horn type size). The volume of the sonicated solution and irradiation time are also variables to be optimized in a case-by-case basis as the mechanisms of US action on crystallization remain to be established. Nevertheless, the results obtained so far make foreseeable that crystal size distribution, and even crystal shape, can be ‘tailored’ by appropriate selection of the sonication conditions.
Crystallization is a process used in many industrial domains including chemical, pharmaceutical and petrochemical industries, and usually considered in terms of nucleation and crystal growth [1]. Nucleation processes – viz. production of microscopic crystals – are classified in Fig. 1. So called “primary nucleation” occurs when a crystal is nucleated in a solution containing no pre-existing crystals. On the other hand, nucleation induced in the bulk of a liquid in the absence of solid surfaces is called “homogeneous nucleation”.
Finally, nucleation induced by pre-existing crystals is called “secondary nucleation” and results from the crystals either acting as templates for new crystal nuclei or fragmenting to produce more nucleation sites. Although nucleation theories have advanced considerably in recent years, the templating or a particular ordering within the solid state via the nucleation process is not fully understood.
True homogeneous nucleation is uncommon in practice, and only happens at high levels of supersaturation. Under such high levels, reversible clustering occurs. Beyond the clustering stage, it appears that a point is reached in the development of order and consolidation at which the cluster is able to “template” further accretion of material into the solid matrix, and a nucleus can be considered to have formed. Although it is not possible to theoretically characterize the transition from a cluster to nucleus, it is probably a continuation of the dynamic process by which clusters originally form as spatial inhomogeneities in the supersaturated solution.
In practice, nucleation almost always occurs heterogeneously, and in theoretically clean and particle-free solutions it is believed to be associated with spurious traces of suspended material or imperfections in the container’s surfaces that function as nucleation sites; thus, it is not surprising that the reproducibility of nucleation in these systems is very poor. The lack of a theoretical understanding of homogeneous nucleation makes it difficult to predict what the effects of ultrasound (US) will be, and whether consideration of primary nucleation is relevant in interpreting the results.
2. Characteristics of sonocrystallization
Research into the influence of US on crystallization processes conducted over the last 70 years has revealed that the nucleation of solid crystals from a number of liquids ranging from organic fluids to metals is affected by the presence of US waves.
There is reliable evidence that applying US not only induces nucleation, but also increases reproducibility; however, the precise mechanisms for US action on crystallization remain to be established. In fact, US can induce primary nucleation in nominally particle-free solutions and, noteworthy, at much lower supersaturation levels than would otherwise be the case. Another effect of US on nucleation is shortening the induction time between the establishment of supersaturation and the onset of nucleation and crystallization.
In addition to the highly spatially resolved regions of extreme excitation, temperature and pressure created by bubble collapse and concomitant release of shock waves, other postulates suggest that, (i) subsequent rapid local cooling rates, calculated at 107–1010 K/s, play a significant role in increasing supersaturation; (ii) localized pressure increases reduce the crystallization temperature; and (iii) the cavitation events allow the excitation energy barriers associated with nucleation to be surmounted, in which case it should be possible to correlate the number of cavitation and nucleation events in a quantitative way. There is clearly a need for further research on the relationship between cavitation and nucleation. Interestingly, it has been suggested that nucleation caused by scratching the walls of a vessel containing a supersaturated solution with a glass rod spatula could be the result of cavitation [1].
Sonocrystallization exhibits a number of features specific to the US wave that clearly distinguish it from crystallization in its absence. For most materials, such features include, (a) faster primary nucleation, which is fairly uniform thorough the sonicated volume; (b) relatively easy nucleation in materials which are usually difficult to nucleate otherwise; (c) the initiation of secondary nucleation; and (d) the production of smaller, purer crystals that are more uniform in size.
Ultrasound has been shown to significantly influence the reduction of agglomeration under given conditions. Three US effects may contribute to this phenomenon. Thus, the shock wave, which is caused by cavitation, can shorten contact between crystals to an extent precluding their bonding together. Also, some agglomeration invariably occurs at the nucleation stage. Nuclei possess a high surface area to volume ratio; this results in a high surface tension which nuclei tend to lower by adhering to one another. The surface tension decreases as crystals grow larger and become more stable, which hinder agglomeration. Finally, the excellent mixing conditions created by US also reduce agglomeration through control of the local nucleus population.
3. Effects of ultrasound on crystallization
Both types of US effects (namely, physical, which facilitate mixing-homogenization, and chemical, resulting from radical formation through cavitation) influence crystallization by altering the principal variables involved in this physical process (namely, induction period, supersaturation concentration and metastable zone width). These effects vary in strength with the nature of the US source and its location; also, their influence is a function of the particular medium to which this form of energy is applied.
3.1. Induction period and supersaturation conditions
This parameter (tind) is defined as the time elapsed between the creation of supersaturation and the appearance of crystals, and decreases as supersaturation increases. Mathematical equations for the induction time that hold for all nuclei forming and growing in a saturated solution have been reported [3]. One of the ways to determined the induction time is from conductivity measurements. Thus, formation of crystals is signaled by a drop in the solution conductivity. The crystallization time is taken to be the time where the derivative of the conductivity with respect to time becomes negative.
