はてなキーワード: s surfaceとは
http://www.dailytitan.com/2011/04/the-inevitable-decline-of-cds/より転載:
Almost 11 years ago, stores like Tower Records and Wherehouse Music were mobbed with over 2.4 million people waiting to purchase N'Sync's No Strings Attached album.
Today, music stores like those are almost non-existent, and those that are still in business do not receive much foot traffic in the CD aisles.
The sales of compact disc albums have seen a significant decline since that record week in 2000. Nielsen Sound Scan reported that over 730 million units sold in 2000. In 2010, album sales hit an all-time low of 326 million units sold, including digitally downloaded albums.
"Nobody wants to go through the trouble of going to a music store, finding and buying a CD, opening the package, etc. Now we just click a button on the Internet and instantly have music," said Keegan Gogerty, 22, a singer/songwriter and radio-TV-film student.
Digitally downloading music has played a major role in the decline of CD sales, but the biggest factor is the illegal digital downloading of music.
Pirating music has been on the rise since Napster launched its peer-to-peer file-sharing software in 1999. Napster was known for allowing users to share and trade their MP3 files with one another over the Internet for free.
Napster was later shut down after multiple lawsuits, but more peer-to-peer outlets surfaced, such as Kazaa, Morpheus and LimeWire.
Peer-to-peer sharing has grown from MP3 sharing to multiple-file sharing and torrent sharing.
"I don't blame people for not wanting to purchase music. If I want to support a band, I will attend their concerts or buy a T-shirt. That is where they receive the most royalties anyway," said Charlie Hatano, an advertising graduate student.
"We live in a generation of simple living, the digital age," Gogerty said.
Online music stores such as iTunes and Napster give consumers the option to purchase music at the click of a button.
However, Ashley Sutton, 24, a psychology major, still buys compact discs.
"Nothing beats getting a new CD, reading the booklet and reading the lyrics," said Sutton. "I agree Internet downloading is more convenient, but I find owning a physical CD collection rewarding, rather than clogging up my computer with music I download."
The music industry has tried to crack down on the peer-to-peer file-sharing software programs, but people are still using different forms of illegally downloading or sharing music.
"I'll admit that I have had friends burn an album for me or copy them into my computer for my iPod," Sutton said. Making copies of CDs, illegally downloading the album and sharing, it is all the same.
In an interview with USAToday.com, the Recording Industry Association of America's (RIAA) CEO said illegal music sharing has been "contained."
"I remember people downloading one song at a time with Napster. More recently I have seen people download 10 albums at the same speed they could download one song in 1999," Hatano said.
A | - | cross sectional area | 断面積 |
C | - | celerity or phase velocity of waves | 波の速さか位相速度 |
C_d | - | drag coefficient | 抗力係数 |
C_s | - | concentration on the seagrass surface | 海中植物の 表面への集中 |
C_w | - | concentration in the water column | 水柱における集中 |
D | - | molecular diffusivity | 分子拡散率 |
D | - | depth | 水深 |
DBL | - | diffusive boundary layer | 拡散境界層 |
δ | - | diffusive boundary layer thickness | 〃 の厚さ |
δ_D | - | diffusive boundary layer (==DBL) | |
δ_l | - | inertial sublayer or logarithmic (log) layer | 内部境界層かログ層 |
δ_v | - | viscous sublayer | 粘性底層 |
F_d | - | friction or viscous drag | 摩擦か粘性抵抗 |
F_p | - | form or pressure drag | 圧力抗力か形状抵抗 |
g | - | acceleration due to gravity | 重力加速度 |
H | - | water depth | 水深 |
H | - | wave height | 波高 |
h | - | canopy height | 林冠の高さ |
J | - | flux | フラックス |
κ | - | von Karman constant | カルマン定数 |
l | - | length scale | 長さスケール |
λ | - | wavelength | 波長 |
m | - | mass | 質量 |
μ | - | molecular or dynamic viscosity | 動粘性係数か分子粘性 |
p | - | hydrostatic or dynamic pressure | 静水圧か動圧 |
Q | - | volume flow rate | 体積流量率 |
ρ | - | density | 密度 |
REI | - | relative wave exposure index | 相対波露出度 |
Re | - | Reynolds number | レイノルズ数 |
Re_crit | - | critical Reynolds number | 臨界レイノルズ数 |
St | - | Stanton number | スタントン数 |
T | - | wave period | 波の周期 |
τ | - | shear stress | 剪断応力 |
τ_o | - | boundary shear stress | 境界剪断応力 |
τ_w | - | wall shear stress | 壁剪断応力 |
μ | - | current velocity | 流速 |
μ* | - | friction velocity | 摩擦速度 |
U_k | - | critical velocity | 臨界速度 |
U_o | - | free stream velocity | 自由流速度 |
ν | - | kinematic viscosity | 動粘性率 |
x | - | horizontal distance | 水平距離 |
χ | - | principal flow direction | 主要流向 |
y | - | cross-stream direction | 交差流の方向 |
z | - | vertical direction or depth | 縦方向か水深 |
z_o | - | roughness height | 荒さの高さ |