UV stray light

UV stray light, Total:214 items.

The international standard classification for "UV stray light" includes: Jewellery , Optical equipment , Alcohols. Ethers , Products of the chemical industry in general , Analytical chemistry in general , Protection against dangerous goods , Solar energy engineering , Waxes, bituminous materials and other petroleum products , Advanced ceramics , Other non-ferrous metals and their alloys , Optoelectronics. Laser equipment , Workplace atmospheres , Animal and vegetable fats and oils , Optics and optical measurements , General methods of tests and analysis for food products , Inks. Printing inks , Petroleum products in general .

The Chinese standard classification for "UV stray light" includes: Artistic handicrafts , Optical instrument in general , Basic organic chemicals , Dye , Electrochemical, thermochemistry and optical profile type analyzer , Marking, packaging, transport and storage in general , Physical power source , Petroleum wax , Special ceramics , Rare metals and their alloys , Special electronic technology material , Labor sanitation , Grease and oil processing and products , Electron optics and other physical optics instrument , Chemical Measurement , Basic standards and general methods , Cosmetics , Printing Technology , Petroleum products in general , chromatograph .

Group Standards of the People's Republic of China

T/SCS 000003-2019 Lead-free UV-A fluorescent lamps
T/CPF 0055-2023 Metal decorating LED-UV offset ink
T/CZZMXH 009-2024 Ultra high pressure short arc ultraviolet lamp for WEE
T/CAQI 74-2019 Gems testing—UV-visble spectroscopy
T/QAS 035-2021 Determination of nitrate in brine by ultraviolet spectrophotometry
T/CSTM 00030-2019 Ultraviolet（UV） curing coatings for vacuum metallization
T/GAMA 29-2023 Optical performance testing method for 3D printed UV projectors
T/CI 350-2024 PVC (Stone and wood plastic) ultraviolet light curing coating
T/STIC 110086-2023 Double Beam UV-VIS Spectrophotometer
T/CI 239-2023 Ultraviolet light（UV）curable screen printing fission ink
T/CASME 1422-2024 UV cured ultra large diameter lined hose
T/ZZB 2358-2021 Ultraviolet curing paint finish wood-based panels
T/COEMA 19O-2024 Near UV field lenses for ultrashort pulsed laser processing
T/QGCML 3950-2024 Technical Specifications for Rapid Heat Dissipation UV Curing Light Sources
T/ZZB 0427-2018 Water-based ultraviolet-curable coatings

General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

GB/T 30809-2014 UV light sources for testing properties of photocatalytic materials
GB/T 25481-2010 On-line ultraviolet/visible spectrum analyzer
GB/T 32737-2016 Determination of nitrate nitrogen in soil—Ultraviolet spectrophotometry method
GB/T 11081-1989 White oils-Determination of ultraviolet absorption
GB/T 14571.4-2008 glycol for industrial use - Determination of ultraviolet transmittance - Ultraviolet spectrophotometric method
GB/T 30456-2013 Rare Earth Ultraviolet Emission Phosphors for Fluorescent Lamps
GB/T 10988-1989 Veiling glare of optical systems--Methods of measurement
GB/T 44567-2024 Optics crystal—Ultraviolet grade calcium fluride crystal
GB/T 22500-2008 Animal and vegetable fats and oils—Determination of ultraviolet absorbance expressed as specific UV extinction
GB/T 25803-2010 Disperse violet HFRL(C.I.Disperse violet 26)
GB/T 16077-1995 Workplace air―Determination of phosgene―Ultraviolet spectrophotometric method
GB/T 26798-2011 Single beam UV/VIS spectrophotometer
GB/T 19394-2003 UV test for photovoltaic (PV) modules
GB/T 10988-2009 Veiling glare of optical systems—Methods of measurement
GB/T 31899-2015 Textile―Tests for weather resistance―UV light exposure
GB/T 11081-2005 Standard test method for ultraviolet adsorption of white oils
GB/T 29883-2013 Packaging for dangerous goods―Rigid plastics intermediate bulk containers―Methods of exposure to laboratory light sources(fluorescence UV lamp)
GB/T 26813-2011 Double beam UV/VIS spectrophotometer

国家市场监督管理总局、中国国家标准化管理委员会

GB/T 14571.4-2022 Test method of ethylene glycol for industrial use—Part 4：Determination of ultraviolet transmittance—Ultraviolet spectrophotometric method
GB/T 25803-2021 C.I. Disperse violet 26（Disperse violet HFRL）

Shanghai Provincial Standard of the People's Republic of China

DB31/ 4-2-1989 UV sterilizer

Professional Standard - Machinery

JB/T 6836-1993 UV filter
JB/T 6777-1993 UV/VIS Spectrophotometer
JB/T 6778-1993 UV/VIS Near Infrared Spectrophotometer
JB/T 6836-2014 Ultra Violet Filter

National Metrological Verification Regulations of the People's Republic of China

JJG 375-1996 UItraviolet Visible Range Spectrophotometer in Single Beam
JJG(地质) 1002-1990 Verification Regulations for UV/Visible Spectrophotometer
JJG 689-1990 UV-VIS-NIR Spectrophotometer
JJG 178-2007 Ultraviolet,Visible,Near-Infrared Spectrophotometers
JJG 682-1990 Verification Regulation of Double Beam UV-VIS Spectrophotometers

Professional Standard - Electron

SJ/T 11475-2014 UV curable coating for optical fibre

工业和信息化部

QB/T 4967-2016 Footwear machines. UV light curing machine
HG/T 5369-2018 Ultraviolet curing coatings for plastic floors
QB/T 5603-2021 Flexo UV curing ink
JB/T 13361-2018 Optical filters for the UV, visible and near-infrared spectral ranges
QB/T 5478-2020 LED-UV curing offset ink
HG/T 5183-2017 Water-based ultraviolet curing coatings for woodenware

Professional Standard - Agriculture

1759药典一部-2010 Appendix VA UV-Vis Spectrophotometry
775兽药典一部-2015 Appendix Contents 0400 Spectroscopy 0401 UV-Vis Spectrophotometry
178药典三部-2015 Spectrophotometry 0401 UV-Vis Spectrophotometry General Principles 19
153药典三部-2010 Appendix Ⅱ Spectrophotometry ⅡA UV-Vis Spectrophotometry
NY/T 1597-2008 Animal and vegetable fats and oils—Determination of ultraviolet absorbance expressed ad specific UV extinction
67药典四部-2015 0401 UV-visible spectrophotometry
2297药典二部-2010 Appendix IV A UV-Vis Spectrophotometry
197药典三部-2020 Spectrophotometry 0401 UV-Vis Spectrophotometry
47药典四部-2020 0401 UV-visible spectrophotometry
772兽药典二部-2015 Appendix Contents 0400 Spectroscopy 0401 UV-Vis Spectrophotometry
269药典第一增补本-2010 A revised variety Zixuesan (Zixue)

Professional Standard - Light Industry

QB/T 2334-1997 Method for the Qualitative Determination of Ultraviolet Absorbents in Cosmetics - Ultraviolet Spectrophotometry
QB/T 4580-2013 Ultraviolet curing ink for ink jet printing
QB/T 2826-2006 Ultra-violet curing offset ink
QB/T 2826-2017 Ultraviolet curing offset ink

Professional Standard - Water Conservancy

SL 84-1994 Determination of nitrogen(nitrate) (Ultraviolet spectrophtometric method)
SL 93.2-1994 Determination of oil and grease (Vltraviolet spectrophotometric method)

Guangdong Provincial Standard of the People's Republic of China

DB44/T 1723-2015 Ultraviolet (UV) Curing Mobile Phone Shell Coatings

Military Standard of the People's Republic of China-General Armament Department

GJB 2148A-2011 Specification for coating cured by ultraviolet light for optical fibre
GJB 3639-1999 Determination of Benzene Chloroacetophenone UV Spectrophotometry
GJB 2148-1994 Specification for UV-curable coatings for optical fibers
GJB 4781-1997*GJBz 20413.3-1997 Determination of Sies by UV spectrophotometry

Professional Standard - Chemical Industry

HG/T 3655-2012 Ultraviolet Curing Coatings for Woodenware
HG/T 3655-1999 Ultraviolet curing coatings for woodenware
HG/T 3655-2024 Ultraviolet (UV) Curing Wood Coatings

Jilin Provincial Standard of the People's Republic of China

DB22/T 2584-2016 Medium-wave ultraviolet light calcium supplement physiotherapy instrument

Shandong Provincial Standard of the People's Republic of China

DB37/T 4149-2020 Determination of water quality UV254 by ultraviolet spectrophotometry
DB37/T 4115-2020 Jewelry and jade identification by ultraviolet-visible spectroscopy

Fujian Provincial Standard of the People's Republic of China

DB35/T 2107-2022 Ultraviolet light-emitting diode evaluation method

Hunan Provincial Standard of the People's Republic of China

DB43/T 2130-2021 Ultraviolet Fluorescent Sulfur Meter Test Method
DB43/T 2659-2023 Technical regulations for hybrid breeding of crape myrtle

National Metrological Technical Specifications of the People's Republic of China

JJF 1641-2017 Program of Pattern Evaluation of Ultraviolet—Visible Spectrophotometers
JJF 1685-2018 Calibration Specification for Ultraviolet Fluorescence Sulfur Analyzers

国家林业局

LY/T 2710-2016 UV curable coating for wooden floors

Professional Standard - Petrochemical Industry

SH/T 0415-1992 Test method for ultraviolet absorbance value of petroleum products
SH/T 0662-1998 Mineral oil - Determination of ultraviolet absorbance
SH/T 1498.7-1997 Nylon 66 salt - Determination of UV index - -Ultraviolet spectrophotometric method
SH/T 0406-1992 Determination method for vaseline ultraviolet absorbance

Taiwan Provincial Standard of the People's Republic of China

CNS 15116-2007 UV test for photovoltaic (PV) modules
CNS 15001-2006 Assessment of solar ultraviolet protective fabrics

Professional Standard - Nuclear Industry

EJ/T 296.2-2014 Determination of trace uranium in urine liquid fluorometry by ultraviolet

Professional Standard - Education

JY/T 022-1996 General rules for ultraviolet and visible absorption spectrometry

国家能源局

SH/T 0966-2017 Determination of aromatic hydrocarbon content in white oil by UV spectrophotometry

BR-ABNT

ABNT NBR 11672-2007 Insumes - Concentrated pigment dispersion - Determination of ultraviolet light color fastness

ITU-R - International Telecommunication Union/ITU Radiocommunication Sector

QUESTION 245-1/4-2009 Out-of-band and spurious emission limits
ITU-R SM.329-8-2000 Spurious Emissions*
ITU-R SM.329-9-2001 Spurious Emissions*
ITU-R SM.329-7-1997 Spurious Emissions

International Telecommunication Union (ITU)

ITU-R QUESTION 245-1/4-2009 Out-of-band and spurious emission limits
ITU-R QUESTION 245-14-2009 Out-of-band and spurious emission limits

American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

ASHRAE EQUIP SI CH 16-2008 ULTRAVIOLET LAMP SYSTEMS

SCC

AWWA JAW72068 Journal AWWA — Effect of UV Treatment on DBP Formation
AWWA JAW54207 Journal AWWA — UV Disinfection Costs for Inactivating Cryptosporidium
AWWA QTC98249 Total Organic Carbon Analysis for Difficult Matrices: An Ultra Violet/Persulfate Approach
NS 9462:2006 Water quality — Determination of UV-absorbance
DANSK DS/EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction
NS-EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2011)
AWWA JAW54208 Journal AWWA — Disinfection of Cryptosporidium parvum With Polychromatic UV Light
DANSK DS/EN ISO 3656/A1:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction
BS EN ISO 3656:2002 Animal and vegetable fats and oils. Determination of ultraviolet absorbance expressed as specific UV extinction
CEI EN 61345:1999 UV test for photovoltaic (PV) modules
DANSK DS/EN 61345:1998 UV test for photovoltaic (PV) modules
AENOR UNE-EN 61345:1999 UV test for photovoltaic (PV) modules
NS-EN ISO 3656:2002 Animal and vegetable fats and oils — Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2002)
10/30197374 DC BS ISO 3656. Animal and vegetable fats and oils. Determination of ultraviolet absorbance expressed as specific UV extinction
AENOR UNE-EN ISO 3656:2011 Oils and fats of animal and vegetable origin. Determination of ultraviolet absorbance expressed as specific UV extinction. (ISO 3656:2011)
AWWA WQTC58791 Benchmarking UV Collimated Beam Testing: Inter-laboratory Comparison of the UV Sensitivity of MS2 Coliphage
AWWA JAW59538 Journal AWWA — Susceptibility of Five Strains of Cryptosporidium parvum Oocysts to UV Light
NS 9303:1986 Personal eye-protectors — Ultra-violet filters — Requirements
MIL MIL-L-51196-1964 LIGHT, ILLUMINATING AND ULTRAVIOLET (NO S/S DOCUMENT)
AWWA WQTC58864 The Search for the Origins of Specific UV Absorbance

International Organization for Standardization (ISO)

ISO 12864:1997 Ophthalmic optics - Contact lenses - Determination of scattered light
ISO 3656:2011 Animal and vegetable fats and oils. Determination of ultraviolet absorbance expressed as specific UV extinction
ISO 9358:1994 Optics and optical instruments - Veiling glare of image-forming systems - Definitions and methods of measurement
ISO 3656:2011/Amd 1:2017 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction; Amendment 1

American Society for Testing and Materials (ASTM)

ASTM E2193-16 Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (using Ultraviolet Spectrophotometry)
ASTM E2193-23 Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (using Ultraviolet Spectrophotometry)
ASTM E387-04 Standard Test Method for Estimating Stray Radiant Power Ratio of Dispersive Spectrophotometers by the Opaque Filter Method
ASTM E387-04(2009) Standard Test Method for Estimating Stray Radiant Power Ratio of Dispersive Spectrophotometers by the Opaque Filter Method
ASTM E3006-20 Standard Practice for Ultraviolet Conditioning of Photovoltaic Modules or Mini-Modules Using a Fluorescent Ultraviolet (UV) Lamp Apparatus
ASTM D4329-13 Standard Practice for Fluorescent Ultraviolet (UV) Lamp Apparatus Exposure of Plastics
ASTM E2193-02 Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (Ultraviolet Spectrophotometric Method)
ASTM E3006-15 Standard Practice for Ultraviolet Conditioning of Photovoltaic Modules or Mini-Modules Using a Fluorescent Ultraviolet (UV) Lamp Apparatus
ASTM E2193-08 Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (Ultraviolet Spectrophotometric Method)
ASTM E2193-02a Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (Ultraviolet Spectrophotometric Method)
ASTM E387-04(2022) Standard Test Method for Estimating Stray Radiant Power Ratio of Dispersive Spectrophotometers by the Opaque Filter Method
ASTM E2193-04 Standard Test Method for Ultraviolet Transmittance of Monoethylene Glycol (Ultraviolet Spectrophotometric Method)
ASTM E387-04(2014) Standard Test Method for Estimating Stray Radiant Power Ratio of Dispersive Spectrophotometers by the Opaque Filter Method
ASTM D4329-05 Standard Practice for Fluorescent UV Exposure of Plastics
ASTM E958-13(2021) Standard Practice for Estimation of the Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers

International Electrotechnical Commission (IEC)

IEC 61345:1998 UV test for photovoltaic (PV) modules
IEC 61228:1993 Method of measuring and specifying the UV-radiation of ultraviolet lamps used for sun-tanning
IEC 61228/AMD1:1996 Method of measuring and specifying the UV-radiation of ultraviolet lamps used for sun-tanning; Amendment 1

Indonesia Standards

SNI 04-6533-2001 UV tests for photovoltaic (PV) moduls
SNI 8169-2015 Penentuan impurities paha rumput laut

International Commission on Illumination (CIE)

CIE 151-2003 SPECTRAL WEIGHTING OF SOLAR ULTRAVIOLET RADIATION
CIE 187-2010 UV-C PHOTOCARCINOGENESIS RISKS FROM GERMICIDAL LAMPS

Spanish Association for Standardization (UNE)

UNE 84170:1983 OIL OF LEMON. ULTRA-VIOLET SPECTROPHOTO METRIC ANALYSIS
UNE-EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2011)
UNE-EN ISO 3656:2002 Animal and vegetable fats and oils. Determination of ultraviolet absorbance expressed as specific UV extinction. (ISO 3656:2002)
UNE-EN 61345:1999 UV TEST FOR PHOTOVOLTAIC (PV) MODULES.
UNE 55047:1973 FATS. SPECTROPHOTOMETRIC MEASURE OF ABSORPTION IN THE ULTRAVIOLET AREA.
UNE-ISO 4735:2009 Oils of Citrus. Determination of CD value by ultraviolet espectrometric analysis

GSO

GSO ISO 3656:2015 Animal and vegetable fats and oils -- Determination of ultraviolet absorbance expressed as specific UV extinction
BH GSO ISO 3656:2016 Animal and vegetable fats and oils -- Determination of ultraviolet absorbance expressed as specific UV extinction
GSO IEC 61345:2015 UV test for photovoltaic (PV) modules
BH GSO IEC 61345:2016 UV test for photovoltaic (PV) modules
GSO ISO 4735:2015 Oils of Citrus -- Determination of CD value by ultraviolet spectrometric analysis
NB/SH/T 0966-2017 Determination of aromatics content in white oil - UV spectrophotometry

Australian/New Zealand Standard (AU-AS/NZS)

AS/NZS 2433:1994 Plastics - Method for exposure to ultraviolet lamps

GM North America

GM GMP.ABS.002-1990 ABS - Ultraviolet Light Stabilized, Low Gloss
GM GMP.ABS.004-1990 ABS - Ultraviolet Light Stabilized, Low Gloss
GMP.ABS.010-1990 ABS - Medium Heat Resistant, UV Stabilized Revision A
GM GM9534P-1993 Ultraviolet/Visible Transmission Through Cured Paint Film

Danish Standards Foundation

DS/EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction
DS/INSTA 518:1987 Flexible intermediate bulk containers. UV-resistance test
DS/EN 61345:1999 UV test for photovoltaic (PV) modules
DS 2322.6:1986 Personal eye-protectors. Ultra-violet filters. Requirements

American National Standards Institute （ANSI)

NEMA LSD 7-1999(S2020) Ultraviolet Radiation from Fluorescent Lamps

German Institute for Standardization

DIN EN ISO 3656:2017-08 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2011 + Amd 1:2017); German version EN ISO 3656:2011 + A1:2017

NO-SN

NS 9462-2006 Water quality Determination of UV-absorbance

Korean Agency for Technology and Standards (KATS)

KS B 5570-2017 Performance test for UV/Vis spectrophotometer
KS B 5570-2022 Performance test for UV/Vis spectrophotometer
KS C IEC 61345-2022 UV test for photovoltaic(PV) modules
KS C IEC 61345-2002(2022) UV test for photovoltaic(PV) modules
KS H ISO 4735-2019 Oils of Citrus－Determination of CD value by ultraviolet spectrometric analysis
KS C IEC 61345-2002(2017) UV test for photovoltaic(PV) modules
KS H ISO 4735-2014(2019) Oils of Citrus－Determination of CD value by ultraviolet spectrometric analysis
KS B ISO 9358:2006 Optics and optical instruments Veiling glare of image-forming systems - Definitions and methods of measurement

British Standards Institution (BSI)

BS EN ISO 3656:2011+A1:2017 Animal and vegetable fats and oils. Determination of ultraviolet absorbance expressed as specific UV extinction
BS EN 61345:1998 UV test for photovoltaic (PV) modules
BS 4995:1973(2011) Recommendations for Measurement ofthe veiling glare index of lenses and optical systems
BS EN ISO 4892-3:1995 Plastics - Methods of exposure to laboratory light sources - Fluorescent UV lamps

Lithuanian Standards Office

LST EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2011)

SE-SIS

SIS SS 84 40 18-1986 Flexible intermediate bulk containers -UV-resistance test

Association Francaise de Normalisation

NF EN ISO 3656:2011 Fatty substances of animal and vegetable origin - Determination of ultraviolet absorbance, expressed in the form of specific extinction in ultraviolet light
NF C57-110:1998 UV test for photovoltaic (PV) modules.
NF T60-223*NF EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction.
NF T60-223/A1*NF EN ISO 3656/A1:2017 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction - Amendment 1

European Committee for Standardization (CEN)

EN ISO 3656:2011 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2011)

CEN - European Committee for Standardization

EN ISO 3656:2002 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction

RU-GOST R

GOST R IEC 61345-2013 Photovoltaic modules. UV test for photovoltaic modules
GOST 34712-2021 Natural gas. Determination of total sulfur by ultraviolet fluorescence method
GOST ISO 4735-2015 Essential oils of citrus. Determination of CD value by ultraviolet spectrometric analysis

Society of Automotive Engineers (SAE)

SAE AS5649A-2019 Wire and Cable Marking Process, UV Laser
SAE AS5649-2012 Wire and Cable Marking Process, UV Laser
SAE AIR5468-2000 Ultraviolet (UV) Lasers for Aerospace Wire Marking

CZ-CSN

CSN 65 7112-1974 Determination of the light fastness oí paraffin waxes on UV light.

European Committee for Electrotechnical Standardization（CENELEC）

EN 61345:1998 UV Test for Photovoltaic (PV) Modules

IN-BIS

IS 1448 Pt.63-1967 Determination of benzene and toluene by UV spectrophotometry

SAE - SAE International

SAE AS5649-2007 Wire and Cable Marking Process@ UV Laser

GOST

GOST ISO 20846-2012 Petroleum products. Determination of sulfur content by ultraviolet fluorescence method

DIN

DIN EN ISO 3656:2002 Animal and vegetable fats and oils - Determination of ultraviolet absorbance expressed as specific UV extinction (ISO 3656:2002)

FI-SFS

SFS 5257-1986 Denna standard ?r fastst?lld p? svenska
SFS 5258-1986 Denna standard ?r fastst?lld p? svenska

General Motors Corporation (GM)

GM 9984266-1995 UV Stabilizer Coatings for Lighting Applications Revision A

Standard Association of Australia （SAA）

ISO 3656:2011/Amd.1:2017 Animal and vegetable fats and oils — Determination of ultraviolet absorbance expressed as specific UV extinction AMENDMENT 1

GOSTR

GOST 34237-2017 Petroleum products. Determination of total sulfur by method ultraviolet fluorescence

United States Navy

NAVY MIL-PRF-24793 A VALID NOTICE 1-2007 ADHESIVE, UV CURABLE, ONE PART, FIBER OPTICS
NAVY MIL-PRF-24793 A-2001 ADHESIVE, UV CURABLE, ONE PART, FIBER OPTICS

NL-NEN

NEN 6306-1990 Vegetable and animal oils and fats Determination of extinction co?ffici?nt in the ultraviolet spectre

Japanese Industrial Standards Committee (JISC)

JIS K 0807:1997 Ultraviolet photometer for monitoring of water pollution