Lihat sumber Isotropi

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'''Isotropi''' ([[kata serapan dalam bahasa Indonesia|serapan]] dari {{lang-nl|isotropie}}) adalah keseragaman atau uniformitas dalam segala arah. Definisi tepatnya tergantung bidang subyeknya. Sebagai "Perkecualian", atau "ketidaksamaan", sering kali diindikasikan dengan tambahan awalan "''an''", menjadi ''anisotropi''.
''Anisotropi'' juga digunakan untuk menyatakan situasi bagi sifat-sifat yang berbeda secara sistematik, tergantung pada arah. "Radiasi isotropik" mempunyai intensitas yang sama tanpa tergantung dari arah [[pengukuran]], dan "medan isotropik" menghasilkan aksi yang sama tanpa tergantung dari orientasi partikel yang diuji.
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==Matematika==
Dalam [[mathematics]], ''isotropi'' mempunyai beberapa arti:
; ''isotropic manifold'': Suatu [[manifold]] is isotropic if the [[geometry]] on the manifold is the same regardless of direction. A similar concept is [[homogeneous space|homogeneity]]. A manifold can be homogeneous without being isotropic, but if it is inhomogeneous, it is necessarily anisotropic.
; [[Isotropic quadratic form]]: A [[quadratic form]] ''q'' is said to be isotropic if there is a non-zero vector ''v'' such that {{nowrap|1=''q''(''v'') = 0}}.
; [[Isotropic coordinates]] on an isotropic chart for [[Lorentzian manifolds]].
; [[Isotropy group]]: An isotropy group is the group of [[isomorphism]]s from any [[object (category theory)|object]] to itself in a [[groupoid]].<ref>A [[groupoid]] <math>\mathcal G</math> is a [[category (mathematics)|category]] where all [[morphism]]s are [[isomorphism]]s, i.e., invertible. If <math>G \in \mathcal G</math> is any object, then <math>\mathcal G(G,G)</math> denotes its [[isotropy group]]: the group of isomorphisms from <math>G</math> to <math>G</math>.</ref>
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== Fisika ==
; [[Mekanika kuantum]] atau [[fisika partikel]]<!--: When a spinless particle (or even an unpolarized particle with spin) decays, the resulting decay distribution ''must'' be isotropic in the rest frame of the decaying particle regardless of the detailed physics of the decay. This follows from [[rotational invariance]] of the Hamiltonian, which in turn is guaranteed for a spherically symmetric potential.-->
:[[Teori kinetik]] juga merupakan contoh isotropi.<!-- It is assumed that the molecules move in random directions and as a consequence, there is an equal probability of a molecule moving in any direction. Thus when there are many molecules in the gas, with high probability there will be very similar numbers moving in one direction as any other hence demonstrating approximate isotropy.

; [[Fluid dynamics]]: Fluid flow is isotropic if there is no directional preference (e.g. in fully developed 3D turbulence). An example of anisotropy is in flows with a background density as gravity works in only one direction.  The apparent surface separating two differing isotropic fluids would be referred to as an isotrope.
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; [[Ekspansi termal]]: suatu benda padat dikatakan isotropik jika ekspasi suatu benda padat itu sama ke segala arah ketika energi termal diberikan kepada benda padat itu.

; Elektromagnetik: Suatu medium isotropik adalah sedemikian sehingga permitivitas (''permittivity''), ε, dan permeabilitas, μ, dari medium itu uniform ke segala arah dalam medium itu. Contoh paling sederhana adalah "ruang bebas" (''free space'').

; [[Optik]]: Isotropi optikal artinya mempunyai sifat optika yang sama di segala arah.<!-- The individual [[reflectance]] or [[transmittance]] of the domains is averaged if the macroscopic reflectance or transmittance is to be calculated. This can be verified simply by investigating, e.g., a [[polycrystalline]] material under a polarizing microscope having the polarizers crossed: If the crystallites are larger than the resolution limit, they will be visible.-->
<div id="Cosmology"></div>
; [[Kosmologi]]: Teori [[dentuman dahsyat]] yang mengawali evolusi alam semesta yang dapat dilihat ini berasumsi bahwa ruang angkasa bersifat isotropik.<ref name="autogenerated1">{{cite web|url=http://map.gsfc.nasa.gov/universe/bb_theory.html |title=WMAP Big Bang Theory |publisher=Map.gsfc.nasa.gov |date= |accessdate=2014-03-06}}</ref> Juga diasumsikan bahwa ruang angkasa adalah homogen.<ref name="autogenerated1"/> Kedua asumsi ini bersama-sama dikenal sebagai Prinsip Kosmologi.<!--Sampai pada tahun 2006, observasi mendorong pendapat bahwa, on distance scales much larger than galaxies, galaxy clusters are [[Great Wall (astronomy)|"Great"]] features, but small compared to so-called multi-verse scenarios.

===Materials science===
[[Image:LvMS-Lvv.jpg|thumb|This sand grain made of [[volcanic]] glass is [[isotropic]], and thus, stays extinct when rotated between [[polarized|polarization filters]] on a [[petrographic microscope]]]]
In the study of [[List of materials properties|mechanical properties of materials]], "isotropic" means having identical values of a property in all directions.  This definition is also used in [[geology]] and [[mineralogy]]. Glass and metals are examples of isotropic materials.<ref>{{cite web|title=Anisotropy and Isotropy|url=http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Structure/anisotropy.htm}}</ref>  Common anisotropic materials include [[wood]], because its material properties are different parallel and perpendicular to the grain, and layered minerals such as [[slate]].

Isotropic materials are useful since they are easier to shape, and their behavior is easier to predict. Anisotropic materials can be tailored to the forces an object is expected to experience. For example, the fibers in [[carbon fiber]] materials and [[rebar]]s in [[reinforced concrete]] are oriented to withstand tension.

===Mikrofabrikasi===
In industrial processes, such as etching steps, isotropic means that the process proceeds at the same rate, regardless of direction. Simple chemical reaction and removal of a substrate by an acid, a solvent or a reactive gas is often very close to isotropic. Conversely, anisotropic means that the attack rate of the substrate is higher in a certain direction. Anisotropic etch processes, where vertical etch-rate is high, but lateral etch-rate is very small are essential processes in [[microfabrication]] of [[integrated circuits]] and [[Microelectromechanical systems|MEMS]] devices.

===Antena (radio)===
An [[isotropic antenna]] is an idealized "[[radiator|radiating element]]" used as a [[reference]]; an [[antenna (electronics)|antenna]] that broadcasts power equally (calculated by the [[Poynting vector]]) in all directions. The gain of an arbitrary antenna is usually reported in [[decibel]]s relative to an isotropic antenna, and is expressed as dBi or dB(i).
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== Biologi ==
; [[Biologi sel]]: Jika sifat-sifat suatu [[dinding sel]] kurang lebih di segala arah, maka dikatakan bersifat isotropik. Bagian interior sel dikatakan anisotropik karena adanya [[organel]] intraseluler .

; [[Fisiologi]]: Dalam sel otot skeletal (atau ''muscle fibers''), istilah " isotropik " merujuk kepada pita-pita terang (pita jenis I) yang berkontribusi menghasilkan "''striated pattern''" pada sel-sel.
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; [[Farmakologi]]: While it is well established that the skin provides an ideal site for the administration of local and systemic drugs, it presents a formidable barrier to the permeation of most substances.<ref>Landman L. “The Epidermal Permeability Barrier.” Anat Embryol (Berl) 1988; 178:1-13 [http://www.springerlink.com/content/x2v22259r84n6k75/]</ref> Most recently, [[isotropic formulations]] have been used extensively in dermatology for drug delivery.<ref>Gregoriadis G. “Lipsomes in Drug Delivery.” Harwood Academic Publishers, 1993; [http://books.google.com.au/books?hl=en&lr=&id=IqqYFne6deEC&oi=fnd&pg=PR7&dq=Liposomes+in+Drug+Delivery&ots=MSjlK_DRqc&sig=XKlC_NXQDndHXkVUepu8rIPaQrU]</ref>
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== Cabang ilmu lain ==
; ''[[Ekonomika]]'' dan ''[[Geografi]]'': suatu daerah isotropik adalah daerah yang mempunyai sifat-sifat yang sama di mana-mana. Daerah seperti itu merupakan suatu konstruksi yang dibutuhkan dalam banyak jenis model.

== Lainya ==
{{Wiktionary}}
<!--* [[Rotational invariance]]-->
* Pita isotropik
* Koordinat isotropik
* Isotropi transvers
* Anisotropi
* Bi-isotropi

== Referensi ==
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[[Kategori:Geometri]]