Adsorption is as an alternative technology to remove colour from wastewater. In this study, activated carbon, prepared from low cost palm oil fibre has been utilised as the adsorbent for the remov...
review de celdas solares sensibilizadas, propiedades de los electrodos
1. Pendahuluan Laser zat cair adalah jenis laser yang menggunakan bahan aktif berupa cairan, seperti dye laser atau disebut juga sebagai laser pewarna. Dye laser ditemukan oleh P. P. Soroki…Full description
This book is about public policy -- what governments do, why they do it, and what difference it makes.Full description
Synthesis of 1-phenyazo-2-naphtholFull description
The hunger of energy of such a vast population is leading us towards our end because its other aspect which is dark and ignored all the time. Till now we are mainly dependent on the fossil fuels like coal, petrol, diesel etc. These fuels generates en
As we know 71 of Earths Surface is covered with water. Water is one of the most essential element for the persistence of life on this planet. Pure and contamination free water is the dire necessity of every living being present on Earth but today wat
This book is about public policy -- what governments do, why they do it, and what difference it makes.
The microbial decolorization of dyes has been of considerable interest biological treatment of the wastewater containing dyes. The bacterial isolate, Bacillus sp. was isolated from the textile effluent sample. Different parameters such as various car
ppt presentation
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The potential of Thespesia Populnea Seed TPS powder, for the removal of Congo red 4B CR dye from aqueous solution was investigated. The adsorbent was characterized by FTIR and SEM analysis. Batch adsorption studies were conducted and various paramete
Liquid Penetrant Inspection
Liquid Penetrant Inspection Dye Penetrant Inspection(DPI) Penetrant Flaw Detection (PFD) Penetrant Testing (PT) • Surface inspection method • Applicabl Applicable e to all non-porous, absorbing materials
non-
6 Steps in Penetrant flaw detection • • • • • •
Surface preparation Penetrant application Removal of excess penetrant Application of developer Inspection Post cleaning and protection
2. Penetrant Application • Penetrating fluid applied to component and drawn into defect by capillary action
Penetrant Application Critical factors
• Penetration / Dwell time • Component Temperature
Principle : Capillary Action • Interaction of adhesive and cohesive forces
Principle : Capillary Action • Interaction of adhesive and cohesive forces
Penetrant Properties • Good Wetting Ability • High Surface Tension • Viscosity
Wetting Ability • Liquids having good wetting ability have a low contact angle. • Liquids having a contact angle of 90º or less will act as penetrants. • Contact angle is strongly affected by surface cleanliness.
Contact Angle Contact Angle
Contact Angle
LOW
HIGH
Surface Tension
HIGH
LOW
Surface Tension
• Strongly affected by contamination
Viscosity • Viscosity is a measure measure of internal internal friction friction • It affects the rate at which a liquid flows • Viscosity has a strong strong effect on the time taken taken for capillary action to work • A high viscosity viscosity penetrant penetrant will require require a longer longer contact time and a longer development time • A low viscosity viscosity penetrant penetrant may may drain too quickly from vertical or overhead surfaces
Types of Penetrant • Colour Contrast • Fluorescent • All other factors factors being being equal, equal, fluorescent fluorescent penetrants provide the best sensitivity • Each of the above may be water washable, solvent removable or post-emulsifiable (in order of increasing sensitivity)
2. Penetrant Application Preceded by a visual inspection Spraying Methods
Brushing Immersion
Penetrant application Electrostatic spraying • Special Methods
Thixotropic penetrants
3. Removal of Excess Penetrant • Penetrating fluid applied to component and drawn into defect by capillary action • Penetrating fluid removed from component surface (but not from defect)
Removal of Excess Penetrant • Water washable • Solvent Removable • Post Emulsifiable
Penetrants are formulated for removal by one or sometimes more than one of the above.
Removal of Excess Penetrant • Water Washable Penetrant
Spray wash
Minimise mechanical action Pressure as low as possible Temperature less than 50ºC
Water Washable Penetrant ADVANTAGES ADVANTAGES • Usable on rough surfaces • Suitable for batch testing • Cheaper than other methods
DISADVANTAGES • Susceptible to over washing • Least sensitive method • Requirement for a water source
Post Emulsifiable Penetrant Stages • Immerse component in penetrant • Immerse component in emulsifier • Emulsifier diffuses into the penetrant making it water washable • Water wash removes excess penetrant / emulsifier
Removal of Excess Penetrant
Hydrophilic 2 Post emulsifica emulsification tion systems Lipophilic Contact time critical Determined by experimentation
Post emulsifiable ADVANTAGES ADVANTAGES • Maximum penetrating ability • Greater control over penetrant removal
DISADVANTAGES • Not suited to rough surfaces • More expensive • More time consuming
Removal of Excess Penetrant Solvent Removable Clean off the excess with a lint free cloth. Wipe with a solvent dampened rag.
Thou shalt not spray the cleaner directly onto the item under test.
Solvent Removable ADVANTAGES ADVANTAGES • Portability • No water supply needed
DISADVANTAGES • Not suited to batch testing • Requires hand wiping so time consuming • More expensive than water washable • Potentially hazardous chemicals
Drying Hot air recirculating oven (max 80ºC) Forced warm air Dry clean compressed air Component temperature shall not exceed 50ºC
4. Development • Penetrating fluid applied to component and drawn into defect by capillary action • Developer applied to surface
Developer Properties • Absorptive Absorptive • Fine texture • Able to mask mask out background colour • Evenly and easily applicable • Light and even coat • Non-fluorescing
Easily wetted Contrasting colour Easily removed Non-toxic and Nonirritant
Developer action • Penetrating fluid applied to component and drawn into defect by capillary action • Developer applied to surface • Penetrant drawn back out of the defect by reverse capillary action
Developer action Capillary Action - Increases the size of an indication i ndication far beyond the actual defect size; increases the “thickness” of an indication, i ndication, thereby thereby increasing it’s colour brilliance. Light scattering - Aids the conversion of UVA to visible light when using fluorescent systems; reduces background glare when using visible systems. Solvent Action - Solvent combines with penetrant, reducing penetrant viscosity, thereby inducing a more rapid, more efficient bleed-out.
Light Scattering I0 If
If
If
If
No Developer
With Developer
No Developer
With Developer
Development Dry powder Component must be dry Applied by Dipping Blowing Dust storm cabinet
Aqueous liquid Dry after application Applied by by Immersion Spraying Brushing
Non-Aqueous liquid Applied by by Aerosol
Dry powder developer ADVANTAGES ADVANTAGES • Easy to handle • No hazardous vapours • Easy to remove
DISADVANTAGES • Difficult to see if properly applied • Fine powders can be hazardous • Does not offer the best degree of colour contrast
Aqueous Developer
• Solutions
Aqueous Developer
• Solutions
• Suspensions
Aqueous Developer ADVANTAGES ADVANTAGES • No vapours or dust • Cheaper than nonaqueous
DISADVANTAGES • Difficult to apply evenly • Requires drying after application
Non-Aqueous Developer ADVANTAGES ADVANTAGES • Most sensitive • Usable with fluorescent or colour contrast
DISADVANTAGES • Hazardous solvents • Higher cost • Need to be correctly applied
System Classification • Type of penetrant • Method of penetrant removal • Type of developer
System classification • • • •
PENETRANT Colour contrast Fluorescent Dual
DEVELOPERS REMOVAL Dry powder Water washable Aqueous Solvent Non-Aqueous Post emulsifiable
5. Inspection • Indications viewed as soon as practicable after developer application with final assessment taking place after a minimum development time has elapsed.
5. Inspection Fluorescent • Allow 15 minutes lamp warm-up • Allow 5 minutes minutes dark dark adaptation adaptation •Do not wear photo-chromatic spectacles
6. Post Cleaning DPI residues are required to be removed because • They may be harmful to the component or • They may impair subsequent processing
Advantages of DPI • • • •
Applicable to all non-porous non-porous materials materials Able to test test large parts parts with a portable portable kit Batch testing Applicable to small parts parts with complex geometry • Simple,cheap, easy to interpret • Good sensitivity • Training requirements typically less than for other NDT methods.
Disadvantages of DPI • • • • • •
Will only detect defects open to the surface Careful surface preparation required Not applicable to porous materials Temperature dependent Cannot retest indefinitely Compatibility of chemicals
Penetrant Systems PENETRANT
REMOVAL
DEVELOPERS
Colour contrast Fluorescent
Solvent
Dry powder
Water washable
Aqueous
Dual
Post emulsifiable Non-Aqueous
Selection of System • • • • • • • •
Nature of discontinuities (size and type) Geometry and intricacy Surface condition Component material and application Size and position Equipment and expertise available Cost Number of components to be tested
Control Checks • Tank levels • Overall system performance
Overall System Performance • Chromium plated cracked test panel • Cracked test piece • Quench cracked aluminium alloy block
Control Checks Tank levels Overall system performance Rinse water temperature Oven temperature Equipment cleanliness Airline filters UV-A filters
Control Checks - Frequency Tank levels Overall system performance Rinse water temperature Oven temperature Equipment cleanliness Airline filters UV-A filters UV-A / visible light levels
Precautions • Avoid looking directly at the lamp • Do not use if filter is cracked, damaged or incorrectly fitted
Fluorescence and the Electromagnetic Spectrum Absorbs
10
100
200
ULTRAVIOLET LIGHT
300
400
Emits
500
600
VISIBLE LIGHT
Dual
700
Fluorescent v Colour Contrast • Fluorescent more sensitive • Less operator fatigue with fluorescent • More difficulty in monitoring fluorescent penetrant removal • Fluorescence may degrade under UV(A), when exposed to acid and high temperatures
