Roborock S7 Robotic Vacuum and Mop Cleaner Official Australian Model – Xiaomi Mobile App

A cleaner, cleanser or cleaning operative is a type of industrial or domestic worker who is tasked with cleaning a space. A janitor (US and Canada), also known as a custodian, porter or caretaker, is a person who cleans and might also carry out maintenance and security duties. A similar position, but usually with more managerial duties and not including cleaning, is occupied by building superintendents in the United States and Canada and by site managers in schools in the United Kingdom.

According to the Cambridge English dictionary a "cleaner" is "a person whose job is to clean houses, offices, public places, etc.:"; the Collins dictionary states that: "A cleaner is someone who is employed to clean the rooms and furniture inside a building." However, a cleaner does not always have to be employed and perform work for pay, such as in the case of volunteer work or community service. "Cleaner" may also refer to cleaning agents e.g. oven cleaner, or devices used for cleaning, e.g. vacuum cleaner.

Cleaning operatives may specialize in cleaning particular things or places, such as window cleaners, housekeepers, janitors, crime scene cleaners and so on. Cleaning operatives often work when the people who otherwise occupy the space are not around. They may clean offices at night or houses during the workday.

A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin modulus, a measure.

Models can be divided into physical models (e.g. a ship model or a fashion model) and abstract models (e.g. a set of mathematical equations describing the workings of the atmosphere for the purpose of weather forecasting). Abstract or conceptual models are central to philosophy of science.

In scholarly research and applied science, a model should not be confused with a theory: while a model seeks only to represent reality with the purpose of better understanding or predicting the world, a theory is more ambitious in that it claims to be an explanation of reality.

A mop (such as a floor mop) is a mass or bundle of coarse strings or yarn, etc., or a piece of cloth, sponge or other absorbent material, attached to a pole or stick. It is used to soak up liquid, for cleaning floors and other surfaces, to mop up dust, or for other cleaning purposes.

An official is someone who holds an office (function or mandate, regardless of whether it carries an actual working space with it) in an organization or government and participates in the exercise of authority (either their own or that of their superior or employer, public or legally private). An elected official is a person who is an official by virtue of an election. Officials may also be appointed ex officio (by virtue of another office, often in a specified capacity, such as presiding, advisory, secretary). Some official positions may be inherited. A person who currently holds an office is referred to as an incumbent. Something "official" refers to something endowed with governmental or other authoritative recognition or mandate, as in official language, official gazette, or official scorer.

Roborock (also known as Beijing Roborock Technology Co. Ltd.; Chinese: 北京石頭世紀科技有限公司) is a Chinese consumer goods company known for its robotic sweeping and mopping devices and handheld cordless stick vacuums. Xiaomi played a key role in the company's founding.

A vacuum (pl.: vacuums or vacua) is space devoid of matter. The word is derived from the Latin adjective vacuus (neuter vacuum) meaning "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure. The Latin term in vacuo is used to describe an object that is surrounded by a vacuum.

The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. But higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10⁻¹²) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm³. Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average in intergalactic space.

Vacuum has been a frequent topic of philosophical debate since ancient Greek times, but was not studied empirically until the 17th century. Clemens Timpler (1605) philosophized about the experimental possibility of producing a vacuum in small tubes. Evangelista Torricelli produced the first laboratory vacuum in 1643, and other experimental techniques were developed as a result of his theories of atmospheric pressure. A Torricellian vacuum is created by filling with mercury a tall glass container closed at one end, and then inverting it in a bowl to contain the mercury (see below).

Vacuum became a valuable industrial tool in the 20th century with the introduction of incandescent light bulbs and vacuum tubes, and a wide array of vacuum technologies has since become available. The development of human spaceflight has raised interest in the impact of vacuum on human health, and on life forms in general.

Xiaomi Corporation (; Chinese: 小米集团), commonly known as Xiaomi, is a Chinese designer and manufacturer of consumer electronics and related software, home appliances, automobiles and household hardware, with headquarters in Beijing, China. It is the second-largest manufacturer of smartphones in the world, behind Samsung, most of which run on the MIUI (now Xiaomi HyperOS) operating system. The company is ranked 338th and is the youngest company on the Fortune Global 500.

Xiaomi was founded in 2010 in Beijing by Lei Jun along with six associates. Lei had founded Kingsoft as well as Joyo.com, the latter of which he sold to Amazon for $75 million in 2004. In August 2011, Xiaomi released its first smartphone and, by 2014, it had the largest market share of smartphones sold in China. Initially the company only sold its products online; however, it later opened brick and mortar stores. By 2015, it was developing a wide range of consumer electronics. In 2020, the company sold 149.4 million smartphones and its MIUI (now HyperOS) mobile operating system has over 500 million monthly active users. As of August 2024, Xiaomi is the second-largest seller of smartphones worldwide, with a market share of about 12%, according to Counterpoint. Its presence led some people to call Xiaomi the "Apple of China". It has come up with its own range of wearable items. It also is a major manufacturer of appliances including televisions, flashlights, unmanned aerial vehicles, and air purifiers using its Internet of things and Xiaomi Smart Home product ecosystems.

Xiaomi keeps its prices close to its manufacturing costs and bill of materials costs by keeping most of its products in the market for 18 months, longer than most smartphone companies. The company also uses inventory optimization and flash sales to keep its inventory low.