Background: Orthopaedic surgeons rely on visual and tactile cues to guide performance in the operating room (OR). However, there is very little data on how sound changes during orthopaedic procedures and how surgeons incorporate audio feedback to guide performance. This study attempts to define meaningful changes in sound during vital aspects of total hip arthroplasty (THA) within the spectrum of human hearing. Methods: 84 audio recordings were obtained during primary elective THA procedures during sawing of the femoral neck, reaming of the acetabulum, acetabular cup impaction, polyethylene liner impaction, femoral broaching, planning of the femoral calcar and press-fit of a porous-coated stem in 14 patients. We graphed changes in frequency intensity across the human spectrum of hearing and sampled frequencies showing differences over time for statistically meaningful changes. Results: Sawing of the femoral neck, polyethylene impaction, and stem insertion showed significant temporal increases in overall sound intensity. Calcar planing showed a significant decrease in sound intensity. Moreover, spectrographic analysis showed that, for each of the critical tasks in THA, there were characteristic frequencies that showed maximal changes in loudness. These changes were above the 1 dB change in intensity required for detection by the human ear. Conclusion: Our results clearly demonstrate reproducible sound changes during total hip arthroplasty that are detectable by the human ear. Surgeons can incorporate sound as a valuable source of feedback while performing total hip arthroplasty to guide optimal performance in the OR. These findings can be extrapolated to other orthopaedic procedures that produce characteristic changes in sound. Moreover, it emphasizes the importance of limiting ambient noise in the OR that might make sound changes hard to distinguish.

There are many approaches to determine the sound propagated from turbulent flows. In hybrid methods, the turbulent noise source field is computed or modeled separately from the far-field calculations. To have an initial and quick estimation of the sound propagation, less computationally intensive methods can be developed using stochastic models of the turbulent fluctuations. In this paper, turbulent mean flow of a two dimensional, compressible, cold-jet at Mach 0.56 is computed using RANS with 2 equation k-e RNG model. The above mean-flow quantities are then used in a stochastic model to generate the details of the turbulent velocity fluctuations. This method is based on the use of classical Langevin equation to model the details of fluctuating flow field superimposed on the averaged computed quantities. The resulting sound field due to the generated unsteady flow is then evaluated using Lighthill's acoustic analogy. Our results are validated by comparing the directivity and the overall sound pressure level (OASPL) magnitudes with the available experimental data. Numerical results show reasonable agreement with the experiments, both in maximum directivity and the magnitude of the OASPL.

For an important nonlinear acoustic model, the (2+1)-dimensional Zabolotskaya–Khokhlov(ZK), a symmetry group and the optimal systems of the symmetry subalgebra have been introduced. Then related symmetry reductions and similarity solutions have been presented via two-stage using of the symmetry group method.

Nowadays, with the increase of population growth and development of industry, noise pollution is increasing, which has been the source of many social and urban anomalies. In addition, noise pollution causes exhaustion and decrease workers productivity in the workplace. Sound is a mechanical wave that requires an environment to transmit. Polymers minimize and remove wave energy due to their viscoelastic properties, especially in viscous regions. This is done through the viscous loss and the sound is absorbed. The literature review shows that the addition of nanoparticles improves the properties of polyurethane foams, especially their acoustic properties. These nanoparticles increase the sound propagation paths through the polymer sample and increase the probability of sound wave attenuation through viscous loss. Depending on the aspect ratio, nanoparticles are divided into various forms including plate-like nanoparticles such as graphene and graphene oxide, nanotubes containing carbon nanotubes and particulate nanoparticles containing metal oxides such as zinc oxide and nanoclays that examined by many researchers to study the effect of each of these nanoparticles on sound absorption in polyurethane foam samples. In this article, first the sound and its properties, then polyurethane as one of the most important members of the polymer family are discussed. Also, among the various forms of polyurethane, polyurethane foams is reviewed.

When computing numerically the solution of a partial differential equation in an unbounded domain usually artificial boundaries are introduced to limit the computational domain. Special boundary conditions are derived at these artificial boundaries to approximate the exact whole-space solution. If the solution of the problem on the bounded domain is equal to the whole-space solution (restricted to the computational domain) these boundary conditions are called transparent boundary conditions (TBCs). This paper discusses the TBCs for general Schrodinger-type pseudo-differential arising from parabolic equation models which have been widely used for one-way wave propagation problems in various application areas, e.g. seismology, optics and plasma physics. Moreover in this paper we will propose a new discrete TBC. The accuracy and relatively lower cpu-time of the new approach is confirmed by the numerical comparisons.      

A theoretical model to predict the dynamics of a shelled micro-bubble driven by acoustic field in a tubular geometric confinement is proposed in the present study. The model is derived from first principle and may not be considered as a variant of Rayleigh-Plesset solution. A semi-analytical model is derived in the form of an ordinary differential equation connecting all parameters involved. Results obtained are in agreement with the available experimental data. The model is further linearized to obtain expression for the forced resonant frequency, which is shown to depend on geometric parameter of confinement as D/ where D and L are the tube diameter and length, respectively. Further, linear viscous damping coefficient is also studied and is found that an overdamped or an underdamped state exist base on shelled micro-bubble size and parameters of geometric confinement (L and D). The state of damping clearly indicate when the shelled micro-bubble in confinement would respond linearly or non-linearly under the influence of acoustic field‎.

Problem statement: The relation between hearing sounds and architecture is one of the neglected matters in studying the embodied experience of architecture. Accordingly, this paper addresses the relation between hearing sounds and place. Research objective: To explore the whatness of the ‘, auditory experience of place, ’,this paper examines the diverse ways of thinking about the relation between sound and place through academic disciplines. Research method: The paper introduces the intellectual foundations and content of these disciplines in a historical context by referring to diverse texts of the field. Therefore, the paper is based on “, inquiry-based”,research rather than a “, hypothesis-based”,one. Conclusion: The analysis indicates three approaches: physical, psychological, and phenomenological. The paper begins with architectural ACOUSTICS, which is the starting point of studying sound and architecture in the field of building physics and indicates a conceptual turn in the studies from ‘, sound’,in sciences (like ACOUSTICS, architectural ACOUSTICS, and psychoACOUSTICS) into ‘, hearing’,in human studies. Human-oriented sound studies include two main approaches: psychological approach, in the soundscape and its sub-disciplines like acoustemology and acoustic ecology as well as aural architecture,and phenomenological approach, in auditory place studies. Finally, the analytical comparison and a conclusion of these approaches indicate the movement of thought in these studies from quantity (in architectural ACOUSTICS aimed at sound control) toward quality (in the soundscape and aural architecture aimed at sound design) and more toward wholeness (in auditory place aimed at auditory understanding of place. )