kPa

キロパスカル

関

kilopascal

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/03/26 01:49:17」(JST)

wiki ja

[Wiki ja表示]

パスカル pascal
記号	Pa
系	国際単位系 (SI)
種類	組立単位
量	圧力・応力
組立	N/m2
定義	1m2につき1Nの圧力・応力
語源	ブレーズ・パスカル

パスカル (pascal, Pa) は、国際単位系 (SI) の圧力・応力の単位である。その名前は、圧力に関する「パスカルの原理」に名を残すブレーズ・パスカルに因む。

1パスカルは、1平方メートル (m²) の面積につき1ニュートン (N) の力が作用する圧力または応力と定義されている。

概説

他の単位との換算は以下のようになる。

• 1 ミリバール (mbar) = 100 Pa = 1 ヘクトパスカル (hPa)
• 1 バール (bar) = 100 000 Pa
  = 100 キロパスカル (kPa) = 0.1 メガパスカル (MPa)
  ≈ 0.987 気圧（標準大気圧） (atm)
  ≈ 約1 標準気圧 (atm)
• 1 標準気圧 (atm)
  = 1.01325 bar = 1013.25 mbar
  = 1 013.25 hPa = 101 325 Pa = 101.325 kPa = 0.101325 MPa
• 1 トル（水銀柱ミリメートル）(mmHg) = 正確に 101 325/760 Pa（計量法体系による）≈ 約133.3224 Pa
• 1 水銀柱インチ (inch Hg) = 正確に 3386.39 Pa（計量法体系による）
• 1 標準気圧 = 約29.92 inches
  （航空機の高度計 (altimeter) は一般にこれを基準として、気圧の変化に合わせて、平均海面 (MSL; mean sea level) からの高度を計器に反映させるために高度計を調整する（高度計規正値/altimeter setting）。高度計規正値の意味で使う場合、水銀柱インチであることは自明のためHgは省略される。）
• 1 工学気圧 = 1 重量キログラム毎平方センチメートル (kgf/cm²) = 98 066.5 Pa = 98.0665 kPa

気象学（天気予報や天気図など）では、世界中で長い間にわたって気圧をミリバールで測定していた。SIが導入された後も、慣習的な圧力の数値がそのまま使われることが希望された。そのため気象学では、今日ではミリバールと同じ値になるヘクトパスカル (hPa) を使用している。日本においては、1992年12月1日からミリバールがヘクトパスカルに置き換えられた。

他の分野では1気圧程度の圧力ならば、キロパスカル (kPa) が使用されている。日本では1999年10月以降、パスカルへの移行が行われた。工学的には今まで使われていた 1 kgf/cm² = 98.0665 kPa で換算しているが、自動車のタイヤの空気圧など一般向けには、1 kgf/cm² = 100 kPa で換算している場合が多い。

なお、旧ソ連で使用されていたメートル・トン・秒単位系において使用されていた圧力の単位ピエーズは、1キロパスカルに等しい。

関連項目

• 圧力の比較
• 単位の換算一覧#圧力・応力

圧力の単位

	パスカル（SI単位）	バール	工学気圧	気圧	トル	psi
1 Pa	≡ 1 N/m²	= 10-5 bar	≈ 10.2×10-6 at	≈ 9.87×10-6 atm	≈ 7.5×10-3 Torr	≈ 145×10-6 psi
1 bar	= 100 000 Pa	≡ 106 dyn/cm²	≈ 1.02 at	≈ 0.987 atm	≈ 750 Torr	≈ 14.504 psi
1 at	= 98 066.5 Pa	= 0.980665 bar	≡ 1 kgf/cm²	≈ 0.968 atm	≈ 736 Torr	≈ 14.223 psi
1 atm	= 101325 Pa	= 1.01325 bar	≈ 1.033 at	≡ p0	= 760 Torr	≈ 14.696 psi
1 Torr	≈ 133.322 Pa	≈ 1.333×10-3 bar	≈ 1.360×10-3 at	≈ 1.316×10-3 atm	≡ 1 mmHg	≈ 19.337×10-3 psi
1 psi	≈ 6894.757 Pa	≈ 68.948×10-3 bar	≈ 70.307×10-3 at	≈ 68.046×10-3 atm	≈ 51.7149 Torr	≡ 1 lbf/in²

wiki en

[Wiki en表示]

Pascal
A pressure gauge reading in psi (red scale) and kPa (black scale)
Unit information
Unit system	SI derived unit
Unit of	Pressure or stress
Symbol	Pa
Named after	Blaise Pascal
In SI base units:	kg⋅m-1⋅s-2

The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. It is defined as one newton per square metre. It is named after the French polymath Blaise Pascal.

Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa) which is equal to one millibar, the kilopascal (1 kPa = 1000 Pa), the megapascal (1 MPa = 1,000,000 Pa), and the gigapascal (1 GPa = 1,000,000,000 Pa).

The unit of measurement called standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sea-level at 45° N. Meteorological reports typically state atmospheric pressure in hectopascals.

Etymology

The unit is named after Blaise Pascal, noted for his contributions to hydrodynamics and hydrostatics, and experiments with a barometer. The name pascal was adopted for the SI unit newton per square metre (N/m²) by the 14th General Conference on Weights and Measures in 1971.

Definition

The pascal can be expressed using SI derived units, or alternatively solely SI base units, as:

where N is the newton, m is the metre, kg is the kilogram, and s is the second.

One pascal is the pressure exerted by a force of magnitude one newton perpendicularly upon an area of one square metre.

Miscellaneous

The unit of measurement called atmosphere or standard atmosphere (atm) is 101325 Pa (101.325 kPa). This value is often used as a reference pressure and specified as such in some national and international standards, such as ISO 2787 (pneumatic tools and compressors), ISO 2533 (aerospace) and ISO 5024 (petroleum). In contrast, IUPAC recommends the use of 100 kPa as a standard pressure when reporting the properties of substances.

The Unicode computer character set has dedicated symbols U+33A9 ㎩ SQUARE PA and U+33AA ㎪ SQUARE KPA in the CJK Compatibility block, but these exist for backward-compatibility with some older ideographic character-sets and are therefore deprecated.

Uses

The pascal (Pa) or kilopascal (kPa) as a unit of pressure measurement is widely used throughout the world and has largely replaced the pounds per square inch (psi) unit, except in some countries that still use the Imperial measurement system, including the United States.

Geophysicists use the gigapascal (GPa) in measuring or calculating tectonic stresses and pressures within the Earth.

Medical elastography measures tissue stiffness non-invasively with ultrasound or magnetic resonance imaging, and often displays the Young's modulus or shear modulus of tissue in kilopascals.

In materials science and engineering, the pascal measures the stiffness, tensile strength and compressive strength of materials. In engineering use, because the pascal represents a very small quantity, the megapascal (MPa) is the preferred unit for these uses.

approximate Young's modulus for common substances

Material	Young's modulus
nylon 6	2–4 GPa
hemp fibre	35 GPa
aluminium	69 GPa
tooth enamel	83 GPa
copper	117 GPa
structural steel	200 GPa
diamond	1220 GPa

The pascal is also equivalent to the SI unit of energy density, J/m³. This applies not only to the thermodynamics of pressurised gases, but also to the energy density of electric, magnetic, and gravitational fields.

In measurements of sound pressure, or loudness of sound, one pascal is equal to 94 decibels SPL. The quietest sound a human can hear, known as the threshold of hearing, is 0 dB SPL, or 20 µPa.

The airtightness of buildings is measured at 50 Pa.

Hectopascal and millibar units

Main article: Bar (unit)

The units of atmospheric pressure commonly used in meteorology were formerly the bar, which was close to the average air pressure on Earth, and the millibar. Since the introduction of SI units, meteorologists generally measure pressures in hectopascals (hPa) unit, equal to 100 pascals or 1 millibar. Exceptions include Canada and Portugal, which uses kilopascals (kPa). In many other fields of science, the SI is preferred, which means Pa with a prefix (in multiples of 3) is preferred.

Many countries also use the millibar or hectopascal to give aviation altimeter settings. In practically all other fields, the kilopascal (1000 pascals) is used instead.

See also

• Centimetre of water
• Metric prefix
• Orders of magnitude (pressure)
• Pascal's law

References

External links

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 長期酸素補充療法 long term supplemental oxygen therapy
• 2. 妊娠中の喘息の生理学および臨床経過 physiology and clinical course of asthma in pregnancy
• 3. 酸素を備えている民間航空機での旅行 traveling with oxygen aboard commercial air carriers
• 4. 肝線維症の非侵襲的評価に用いられる検査 tests used for the noninvasive assessment of hepatic fibrosis
• 5. 換気調節障害 disorders of ventilatory control

English Journal

• Hydroxypropyl methylcellulose based aerogels: Synthesis, characterization and application as adsorbents for wastewater pollutants.

• Martins BF1, de Toledo PV2, Petri DF3.
• Carbohydrate polymers.Carbohydr Polym.2017 Jan 2;155:173-181. doi: 10.1016/j.carbpol.2016.08.082. Epub 2016 Aug 26.
• Hydroxypropyl methylcellulose (HPMC) E4M and J5MS samples with degrees of substitution of methyl groups (DS) 1.9 and 1.5, respectively, and molar substitutions of hydroxypropyl groups (MS) 0.25 and 0.75, respectively, were used to create aerogels in the presence of citric (cit), oxalic (oxa) or tere
• PMID 27702501

• Effects of Residual Stress, Axial Stretch, and Circumferential Shrinkage on Coronary Plaque Stress and Strain Calculations: A Modeling Study Using IVUS-Based Near-Idealized Geometries.

• Wang L1, Zhu J2, Samady H3, Monoly D3, Zheng J4, Guo X5, Maehara A6, Yang C7, Ma G2, Mintz GS6, Tang D8.
• Journal of biomechanical engineering.J Biomech Eng.2017 Jan 1;139(1). doi: 10.1115/1.4034867.
• Accurate stress and strain calculations are important for plaque progression and vulnerability assessment. Models based on in vivo data often need to form geometries with zero-stress/strain conditions. The goal of this paper is to use IVUS-based near-idealized geometries and introduce a three-step m
• PMID 27814429

• High-efficiency piezoelectric micro harvester for collecting low-frequency mechanical energy.

• Li X1, Song J, Feng S, Xie X, Li Z, Wang L, Pu Y, Soh AK, Shen J, Lu W, Liu S.
• Nanotechnology.Nanotechnology.2016 Dec 2;27(48):485402. Epub 2016 Nov 7.
• A single-layer zinc oxide (ZnO) nanorod array-based micro energy harvester was designed and integrated with a piezoelectric metacapacitor. The device presents outstanding low-frequency (1-10 Hz) mechanical energy harvesting capabilities. When compared with conventional pristine ZnO nanostructured pi
• PMID 27819801

Japanese Journal

• Morphological changes in branchial mitochondria-rich cells of the teleost Paralichthys olivaceus as a potential indicator of CO2 impacts

• Hayashi Masahiro,Kikkawa Takashi,Ishimatsu Atsushi
• Marine Pollution Bulletin 73(2), 409-415, 2013-08-30
• … We studied the morphological and biochemical changes of mitochondria-rich cells (MRCs) of a demersal teleost, Paralichthys olivaceus, during exposure to 0.98, 2.97 and 4.95kPa pCO2. … The apical opening area of MRCs increased 2.2 and 4.1 times by 24h exposure to 2.97 and 4.95kPa pCO2, respectively, while the cross-sectional area or density of MRCs did not change. …
• NAID 120005341838

• A layer-by-layer deposition mechanism for producing a pyrolytic carbon coating on carbon nanotubes

• Zheng Guo-Bin,Sano Hideaki,Uchiyama Yasuo
• Carbon 57, 267-273, 2013-06-00
• … The deposition of PyC was carried out at temperature between 800 and 1000 °C using propane as carbon source with or without a hydrogen carrier gas at low pressure of 20 kPa. …
• NAID 120005311961

• Optimal cyclic compressive loading promotes differentiation of 3D-cultured pre-osteoblasts

• Ota Keisuke,Muroi Yuri,Kakudo Kenji,Nakata Ken
• Journal of Osaka Dental University 47(1), 117-125, 2013-04-00
• … It showed significantly increased expressions of Col Ia1, ALP, RUNX2, osterix and Dlx5 at 5 kPa. … The LL group also showed significantly increased expressions of Col Ia1, osterix, and Dlx5 at 20 kPa, and significantly decreased expressions of osteocalcin at 40 kPa. … Mechanical loading at 5 kPa promoted differentiation, suggesting that optimal cyclic compressive loading induced the bone differentiation of pre-osteoblasts. …
• NAID 110009603285

Related Links

• パスカル - Wikipedia

1 013.25 hPa = 101 325 Pa = 101.325 kPa = 0.101325 MPa; 1 標準気圧 = 約 29.92 inches ... 工学的には今まで使われていた 1 kgf/cm2 = 98.0665kPa で換算して いるが、自動車のタイヤの空気圧など一般向けには、1 kgf/cm2 = 100 kPa で換算して ...

Related Pictures

---

★リンクテーブル★

リンク元	「kilopascal」
関連記事	「k」

「kilopascal」

　　[★]

キロパスカル

関

kPa

「k」

　　[★]

• キロ kilo (10の3乗)
• 解離定数 dissociation constant
• 比例定数 rate constant