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Hidaka T.,Takenaka R and D Institute
39th International Congress on Noise Control Engineering 2010, INTER-NOISE 2010 | Year: 2010

In auditoriums, the acoustical quality differs from one seat to another. This paper examines the spread of acoustical quality in concert halls having three different shapes, shoebox, nonshoebox, and surround. The total acoustical quality is defined as: TAQ = [IACC E3-IACC E3,Avg] 3/2 + [G-G Avg] 3/2 + [EDT-EDT Avg] 3/2. If we write IACC E3 = log(iacc E3) and G = 10log(E), we can write the relative spread as: ΔTAQ= √([Δiacc E3/iacc E3,Avg] 2 + [ΔE/E Avg] 2 + [ΔEDT/EDT Avg] 2). The comparison of the spread in ΔTAQ was measured in 18 concert halls. The results were that the spreads depend significantly on the hall shape, and the largest spread is in the parameter IACC E3. Thus, IACC E3 is judged to be the most significant quantity in the measurement of the spread in acoustical quality from one shape of hall to another. Source

Nakai M.,Takenaka Corporation | Tanno Y.,Takenaka Corporation | Oka H.,Takenaka R and D Institute | Fujii E.,Takenaka Corporation
AIJ Journal of Technology and Design | Year: 2013

This paper reports the result of case studies for a large scale dome structure with a diameter of approximately 300m. Schematic designs of a total of four domes are conducted to quantitatively evaluate the advantages of using high-strength steel and/or seismic isolation. It is shown that the unit structural weight of the dome with high-strength steel and base isolation can be as small as half of the one without the two. Source

Kohmura Y.,Takenaka R and D Institute
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014

There are several reports that the static Young's modulus of rocks differs from the dynamic one. In this study, the relation between static Young's modulus and dynamic Young's modulus of rocks is examined. First, static Young's modulus was obtained by the uni-axial compression test, and dynamic Young's modulus was obtained by the ultrasonic transmission method. Secondly, their relationship was examined from the viewpoint of the strain level. In addition, the value of the Poisson's ratio for calculation of dynamic Young's modulus was examined. As a result, it was clarified that the dynamic Young's modulus becomes almost equal to the static one determined from the region of small strain if the Poisson's ratio used to calculate the dynamic Young's modulus is the appropriate value which is measured at the strain level without effect of crack closure. © 2014 The Society of Materials Science, Japan. Source

Nishihara N.,Takenaka R and D Institute | Hidaka T.,Takenaka R and D Institute
Journal of the Acoustical Society of America | Year: 2012

Objective acoustical parameters for halls are often measured in 1-octave bands with mid-frequencies from 125 to 4000 Hz. In reality, the frequency range of musical instruments is much wider than that, and the fundamentals of the lower notes of bass instruments are contained in 31.5 or 63 Hz bands. Overtones of fundamentals in these bands fall in 125 Hz band. This report presents subjective experiments designed to determine to what extent the overtones in 125 Hz band and higher bands influence the loudness sensation of the components in 63 Hz band. In the experiments, the 125 Hz and higher components of the musical tone are used to act as a masker against the lower component used as a maskee. The threshold of the difference between G(125 Hz) and G(lower band) that just enables one to hear the fundamental tones in the lower band is determined. Masked loudness of 63 Hz sinusoidal tone caused by partial masking noise with higher frequencies was determined based on a similar procedure to the masked loudness-matching function. The result indicates that the difference in loudness of low tone will not be noticeable even if G changed by ±2.5 to ±3 dB, at least when there are other accompanying instruments. © 2012 Acoustical Society of America. Source

Kohmura Y.,Takenaka R and D Institute
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2012

In this study the uni-axial compression test using the stress-feedback method was carried out with Inada granite which is a Class II rock. The test was carried out by changing loading direction and water content conditions. A perfect stress-strain curve was measured. The stress-strain curve including the post-failure region was simulated using a spring model. In addition, the effects of anisotropy and water content conditions on the stress strain characterization were examined. © 2012 The Society of Materials Science, Japan. Source

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