Many libraries adopted Internet filters after Congress conditioned the receipt of universal service discounts on the use of Internet filters through the Children's Internet Protection Act ( CIPA ).

Many content filters have an option which allows authorized people to bypass the content filter.

Many scare stories have originated from various Russian gas masks and their filters that are now common in surplus stores ; the GP-5 was often considered to have an asbestos filter, however like most cold-war masks it only contains activated charcoal.

Many digital filters are based on the Fast Fourier transform, a mathematical algorithm that quickly extracts the frequency spectrum of a signal, allowing the spectrum to be manipulated ( such as to create band-pass filters ) before converting the modified spectrum back into a time-series signal.

Many second-order filters are designed to have " peaking " or resonance, causing their frequency response at the cutoff frequency to be above the horizontal line.

Many fundamental DSP algorithms, such as FIR filters or the Fast Fourier transform ( FFT ) depend heavily on multiply – accumulate performance.

Many machines use " spin disc filters ", which remove the muck from the filter by centripetal force while it is back washed with solvent.

Many graphical software products ( e. g. Adobe Photoshop or GIMP ) offer simple motion blur filters.

Many household water filters and fish tanks use activated carbon filters to further purify the water.

Many current browsers do contain features similar to those provided by Proxomitron filters – blocking advertisements and pop-ups, for example.

Many RVs have built-in water filters.

Many types of filters exist for applications including graphic equalizers, synthesizers, sound effects, CD players and virtual reality systems.

Many power strips have built-in surge protectors or EMI / RFI filters: these are sometimes described as surge suppressors or electrical line conditioners.

Many filters absorb part of the light available, necessitating longer exposure.

Many other manufacturers make filters to fit Cokin holders.

Many filters use gravity, or gravity enhanced by vacuum ( suction ) in order to create this separation, often through a funnel-shaped device.

Many wear visors, goggles or have light filters implanted into their eyes, a sensitivity to light being a common Delaque weakness.

Many earlier multi-shot backs could natively capture only grayscale images ; color images were created by scanning three times through red, green, and blue filters which rotated into place.

Many municipal systems in the U. S. initially used slow sand filters, but as cities have grown they subsequently installed rapid sand filters, due to increased demand for drinking water.

Many games, such as World of Warcraft, and more recently, Habbo Hotel and RuneScape allow the user to turn the filters off.

When this safety filter is activated, it filters out the inappropriate links from all of the search results.

Repetitive sequences in the database or query can also distort both the search results and the assessment of statistical significance ; BLAST automatically filters such repetitive sequences in the query to avoid apparent hits that are statistical artifacts.

DC ++ itself has several specialized spin-off open-source versions as well, such as BCDC ++ and StrongDC ++, which are refined with features particular to user groups, such as filters, language packs, and search capabilities.

* CA Directory: CA Directory contains pre-caching engine which can index all attributes that are used in LDAP search filters, and caching all attributes returned in search results.

Other features common to outliners include the ability to use full text search which aids in quickly locating information and filters enable you to drill down to see only information relevant to a specific query.

When the user clicks in the search box, a menu shows up below it showing recent searches as well as suggested Advanced Query Syntax filters that the user can type.

The user-selected logic and filters are then applied to this inverted list to generate the final search results.

The search engine first filters search terms in several ways.

Examples of policy appliance technologies for rules-based processing include analytic filters, contextual search, semantic programs, labeling and wrapper tools, and DRM, among others ; policy appliance technologies for selective disclosure include anonymization, content personalization, subscription and publishing tools, among others ; and, policy appliance technologies for accountability and oversight include authentication, authorization, immutable and non-repudiable logging, and audit tools, among others.

Another search engine, Blekko also regards eHow as spam, blacklists the site and filters eHow results out.

Some swear filters do a simple search for a string.

There were several problems with these engines, including water and corrosion in the injectors ( no water separator in the fuel line ), paraffin clogging of fuel lines and filters in cold weather, reduced lubrication in the heads due to undersized oil galleys, head bolt failures, and the use of aluminum rockers and stanchions in the 4. 3L engines.

Piston engines ( especially if turbocharged ) also need well-maintained filters, but they are more resilient if the filter does fail.

The main application for air filters are combustion air to engines.

Therefore, it is recommended to change the fuel filters on engines and heaters shortly after first switching to a biodiesel blend.

Ash fall will block air and oil filters and abrade any moving parts if ingested into engines.

Dogpile is a metasearch site — it searches multiple engines, filters for duplicates and then presents the results to the user.

The Ilmor factory filters the noise and heat of the engines under test through large water tanks, both to reduce the noise and to heat the factory.

Some modern diesel engines feature diesel particulate filters, which catch the black soot and when saturated are automatically regenerated by burning the particles.

Air filters are used in applications where air quality is important, notably in building ventilation systems and in engines.

The air intakes of internal combustion engines and compressors tend to use either paper, foam, or cotton filters.

The excessive particle emissions of diesel engines have also been cut back with particulate filters, which are offered for most modern diesel engines.

The RAI 40-700 class ( see Iranian Railways RC4 ) of eight engines were exported to Iran in the early eighties for use on the electrified stretches near the then-Soviet border ; these were based on Rc4 but with Rm-type bogies, sand-proof air filters and no round windows on the side.

Also, there were frequent engine failures as the air filters were overwhelmed by the volume of dust produced by flailing or the engines overheated because of the desert environment.

Some filters, especially found on diesel engines, are of a bowl-like design which collect water in the bottom ( as water is more dense than diesel ).