This paper presents how the shape of a brass instrument can be optimized with respect to its intonation properties. The instrument is modeled using a hybrid method between a lossy one-dimensional transmission line analogy for the slowly flaring part of the instrument, and a two-dimensional finite element model for the rapidly flaring part. The optimization employs gradient-based algorithms, and...

Growth of semiconductor nanowires on cheap metal substrates could pave the way to the large-scale manufacture of low-cost nanowire-based devices. In this work, we demonstrated that high density InN nanowires can be directly grown on brass substrates by metal-organic chemical vapor deposition. It was found that Zn from the brass substrates is the key factor in the formation of nanowires by restr...

One of the solutions for density measurement is to make use gamma-ray transmission technique. We studied by this technique, using Co-60 and Cs-137. Each source, without materials in geometry, was counted noted intensities as (I0). All were (I). [I/I0] rates calculated. Now, could be determined via Beer-Lambert Equation. Experimental application performed on industrial metals or metal alloys lik...

Frequency jumps are a common phenomenon in voice production. They are perceived as discontinuities in voice pitch caused by smooth changes of physiological parameters, and may be observed in transitions between chest and falsetto vocal registers. Here, a recent model of birdsong production is used to model an oscillator source for the vocal folds coupled to an acoustic waveguide for the vocal t...

African elephants (Loxodonta africana) produce a broad diversity of sounds ranging from infrasonic rumbles to much higher frequency trumpets. Trumpet calls are very loud voiced signals given by highly aroused elephants, and appear to be produced by a forceful expulsion of air through the trunk. Some trumpet calls have a very distinctive quality that is unique in the animal kingdom, but resemble...

nowadays, tube bonding in vehicles structure is noticeably considered by many researches. in this paper, local tube compression process by a rubber ring has been studied. firstly, simulation of the process was performed by fem. then, experimental test has been carried out to validate the numerical results. numerical and experimental results were compared showing a good agreement. in the second ...