Linear actuatorA linear actuator is an actuator that creates motion in a straight line, in contrast to the circular motion of a conventional electric motor. Linear actuators are used in machine tools and industrial machinery, in computer peripherals such as disk drives and printers, in valves and dampers, and in many other places where linear motion is required. Hydraulic or pneumatic cylinders inherently produce linear motion. Many other mechanisms are used to generate linear motion from a rotating motor.
Molecular diffusionMolecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules.
Credit cardA credit card is a payment card issued to users (cardholders) to enable the cardholder to pay a merchant for goods and services based on the cardholder's accrued debt (i.e., promise to the card issuer to pay them for the amounts plus the other agreed charges). The card issuer (usually a bank or credit union) creates a revolving account and grants a line of credit to the cardholder, from which the cardholder can borrow money for payment to a merchant or as a cash advance.
Contactless smart cardA contactless smart card is a contactless credential whose dimensions are credit-card size. Its embedded integrated circuits can store (and sometimes process) data and communicate with a terminal via NFC. Commonplace uses include transit tickets, bank cards and passports. There are two broad categories of contactless smart cards. Memory cards contain non-volatile memory storage components, and perhaps some specific security logic.
Byte (magazine)Byte (stylized as BYTE) was a microcomputer magazine, influential in the late 1970s and throughout the 1980s because of its wide-ranging editorial coverage. Byte started in 1975, shortly after the first personal computers appeared as kits advertised in the back of electronics magazines. Byte was published monthly, with an initial yearly subscription price of $10. Whereas many magazines were dedicated to specific systems or the home or business user's perspective, Byte covered developments in the entire field of "small computers and software", and sometimes other computing fields such as supercomputers and high-reliability computing.
Octopus cardThe Octopus card is a reusable contactless stored value smart card for making electronic payments in online or offline systems in Hong Kong. Launched in September 1997 to collect fares for the territory's mass transit system, it has grown into a widely used system for transport and other retail transactions in Hong Kong. It is also used for purposes such as recording school attendance and permitting building access. The cards are used by 98 percent of the population of Hong Kong aged 15 to 64 and the system handles more than 15 million transactions, worth over HK$220 million, every day.
Credit card fraudCredit card fraud is an inclusive term for fraud committed using a payment card, such as a credit card or debit card. The purpose may be to obtain goods or services or to make payment to another account, which is controlled by a criminal. The Payment Card Industry Data Security Standard (PCI DSS) is the data security standard created to help financial institutions process card payments securely and reduce card fraud.
