Hunter Acela 52 in. Hunter Express Integrated LED Indoor Matte Silver Ceiling Fan with Remote and Light Kit Included

52 may refer to:

• 52 (number)
• one of the years 52 BC, AD 52, 1952, 2052
• 52-hertz whale an individual male whale, also known as the loneliest whale, calling at the unusual 52 hertz range
• 52 (comics), a 2006–07 American weekly comic book series
• 52 (album series), series of albums by American singer Kristian Bush
• 52 Europa, a main-belt asteroid
• Tatra 52, a mid-size car

The Acela ( ə-SEL-ə; originally the Acela Express until September 2019) is Amtrak's flagship passenger train service along the Northeast Corridor (NEC) in the Northeastern United States between Washington, D.C. and Boston via 13 intermediate stops, including Baltimore, New York City and Philadelphia. Acela trains are the fastest in the Americas, reaching 150 miles per hour (240 km/h) (qualifying as high-speed rail), but only over 49.9 miles (80.3 km) of the 457-mile (735 km) route.

Acela carried more than 2.9 million passengers in fiscal year 2023, second only to the slower and less expensive Northeast Regional, which had over 9 million passengers. Ridership is down from the pre-Covid-19 pandemic high of 3,557,455 passengers in 2019. Its 2016 revenue of $585 million was 25% of Amtrak's total.

Acela operates along routes that are used by freight and slower regional passenger traffic, and reaches the maximum allowed speed of the tracks only along some sections, with the fastest peak speed along segments between Mansfield, Massachusetts, and Richmond, Rhode Island, and South Brunswick and Trenton, New Jersey. Acela trains use active tilting technology, which helps control lateral centrifugal force, allowing the train to travel at higher speeds on the sharply curved NEC without disturbing passengers. The high-speed operation occurs mostly along the 226-mile (364 km) route from Pennsylvania Station in New York City to Union Station in Washington, D.C., with a fastest scheduled time of 2 hours and 45 minutes and an average speed of 82 miles per hour (132 km/h), including time spent at intermediate stops. Over this route, Acela and the Northeast Regional service captured an 83% share of air/train commuters between New York and Washington in 2021, up from 37% in 2000.

The Acela's speed is limited by traffic and infrastructure on the route's northern half. On the 231-mile (372 km) section from Boston's South Station to New York's Penn Station, the fastest scheduled time is 3 hours and 30 minutes, or an average speed of 66 miles per hour (106 km/h). Along this section, Acela has captured a 54% share of the combined train and air market. The entire 457-mile (735 km) route from Boston to Washington takes between 6 hours, 38 minutes and 6 hours, 50 minutes, at an average speed of around 70 miles per hour (110 km/h).

The present Acela Express equipment will be replaced by new Avelia Liberty trainsets, beginning in 2024. The new trains will have greater passenger capacity and an enhanced active tilt system that will allow higher speed on the many curved sections of the route.

A ceiling is an overhead interior roof that covers the upper limits of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the roof structure or the floor of a story above. Ceilings can be decorated to taste, and there are many examples of frescoes and artwork on ceilings, especially within religious buildings. A ceiling can also be the upper limit of a tunnel.

The most common type of ceiling is the dropped ceiling, which is suspended from structural elements above. Panels of drywall are fastened either directly to the ceiling joists or to a few layers of moisture-proof plywood which are then attached to the joists. Pipework or ducts can be run in the gap above the ceiling, and insulation and fireproofing material can be placed here. Alternatively, ceilings may be spray painted instead, leaving the pipework and ducts exposed but painted, and using spray foam.

A subset of the dropped ceiling is the suspended ceiling, wherein a network of aluminum struts, as opposed to drywall, are attached to the joists, forming a series of rectangular spaces. Individual pieces of cardboard are then placed inside the bottom of those spaces so that the outer side of the cardboard, interspersed with aluminum rails, is seen as the ceiling from below. This makes it relatively easy to repair the pipes and insulation behind the ceiling, since all that is necessary is to lift off the cardboard, rather than digging through the drywall and then replacing it.

Other types of ceiling include the cathedral ceiling, the concave or barrel-shaped ceiling, the stretched ceiling and the coffered ceiling. Coving often links the ceiling to the surrounding walls. Ceilings can play a part in reducing fire hazard, and a system is available for rating the fire resistance of dropped ceilings.

Fan commonly refers to:

• Fan (machine), a machine for producing airflow, often used for cooling
• Hand fan, an implement held and waved by hand to move air for cooling
• Fan (person), short for fanatic; an enthusiast or supporter, especially with regard to entertainment

Fan, FAN or fans may also refer to:

Indoor(s) may refer to:

• the interior of a building
• Indoor environment, in building science, traditionally includes the study of indoor thermal environment, indoor acoustic environment, indoor light environment, and indoor air quality
• Built environment, the human-made environment that provides the setting for human activity
• Indoor athletics
• indoor games and sports

Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively optical radiation.

In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization. Its speed in vacuum, 299792458 m/s, is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and particles. The study of light, known as optics, is an important research area in modern physics.

The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.

Silver is a chemical element; it has symbol Ag (from Latin argentum 'silver', derived from Proto-Indo-European *h₂erǵ 'shiny, white') and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. Silver is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.

Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures.

Other than in currency and as an investment medium (coins and bullion), silver is used in solar panels, water filtration, jewellery, ornaments, high-value tableware and utensils (hence the term "silverware"), in electrical contacts and conductors, in specialised mirrors, window coatings, in catalysis of chemical reactions, as a colorant in stained glass, and in specialised confectionery. Its compounds are used in photographic and X-ray film. Dilute solutions of silver nitrate and other silver compounds are used as disinfectants and microbiocides (oligodynamic effect), added to bandages, wound-dressings, catheters, and other medical instruments.

With or WITH may refer to:

• With, a preposition in English
• Carl Johannes With (1877–1923), Danish doctor and arachnologist
• With (character), a character in D. N. Angel
• With (novel), a novel by Donald Harrington
• With (album), a 2014 album by TVXQ
• With (EP), a 2021 EP by Nam Woo-hyun