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Perimeter Fence
Demarcation of a perimeter, when the protection of assets, personnel or buildings is required, is normally affected by the building of a perimeter fence system. The level of protection offered varies according to the threat level to the perimeter. Different types of perimeter fencing include: * Chain-link fencing * Metal railings * Palisade fencing * Rolled mesh fencing * Timber fencing * Welded wire mesh fence fencing Vertical bar fencing has been the most popular form of perimeter security fence since the 1980s. Since the 2000s, welded wire mesh and acoustic barriers have also become popular types of perimeter fence around the world. Vertical bar, acoustic barriers and welded mesh are used in commercial projects and landmarks, and transport hubs. In high-security applications, sensors may be attached to the fence that generate alarms when they detect someone cutting, climbing, or lifting the fence fabric. Purpose The purpose of perimeter fence is to stop or prevent the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perimeter
A perimeter is the length of a closed boundary that encompasses, surrounds, or outlines either a two-dimensional shape or a one-dimensional line. The perimeter of a circle or an ellipse is called its circumference. Calculating the perimeter has several practical applications. A calculated perimeter is the length of fence required to surround a yard or garden. The perimeter of a wheel/circle (its circumference) describes how far it will roll in one revolution. Similarly, the amount of string wound around a spool is related to the spool's perimeter; if the length of the string was exact, it would equal the perimeter. Formulas The perimeter is the distance around a shape. Perimeters for more general shapes can be calculated, as any path, with \int_0^L \mathrms, where L is the length of the path and ds is an infinitesimal line element. Both of these must be replaced by algebraic forms in order to be practically calculated. If the perimeter is given as a closed piecewise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obstacle
An obstacle (also called a barrier, impediment, or stumbling block) is an object, thing, action or situation that causes an obstruction. A obstacle blocks or hinders our way forward. Different types of obstacles include physical, economic, biopsychosocial, cultural, political, technological and military. Types Physical As physical obstacles, we can enumerate all those physical barriers that block the action and prevent the progress or the achievement of a concrete goal. Examples: * architectural barriers that hinder access to people with reduced mobility; * doors, gates, and access control systems, designed to keep intruders or attackers out; * large objects, fallen trees or collapses through passageways, paths, roads, railroads, waterways or airfields, preventing mobility; * sandbanks, rocks or coral reefs, preventing free navigation; * hills, mountains and weather phenomena preventing the free traffic of aircraft; * meteors, meteorites, micrometeorites, cosmic dust, co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Privacy Fencing
A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or net (textile), netting. A fence differs from a wall in not having a solid foundation along its whole length. Alternatives to fencing include a ditch (fortification), ditch (sometimes filled with water, forming a moat). Types By function * Agricultural fencing, to keep livestock in and/or predators out * Blast fence, a safety device that redirects the high energy exhaust from a jet engine * Sound barrier or acoustic fencing, to reduce noise pollution * Crowd control barrier * Privacy fencing, to provide privacy and security * Temporary fencing, to provide safety, security, and to direct movement; wherever temporary access control is required, especially on building and construction sites * Perimeter fencing, to prevent trespassing or theft and/or to keep children and pets from wandering away. * Decorative fencing, to enhan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hillsborough Disaster
The Hillsborough disaster was a fatal crowd crush at a football match at Hillsborough Stadium in Sheffield, South Yorkshire, England, on 15 April 1989. It occurred during an FA Cup semi-final between Liverpool and Nottingham Forest in the two standing-only central pens within the Leppings Lane stand allocated to Liverpool supporters. Shortly before kick-off, police match commander David Duckenfield ordered exit gate C to be opened in an attempt to ease crowding, which led to an influx of supporters entering the pens. This resulted in overcrowding of those pens and the fatal crush; with a total of 97 fatalities and 766 injuries, the disaster is the deadliest in British sporting history. Ninety-four people died on the day; one more died in hospital days later, Tony Bland died in 1993, and in 2021, Andrew Devine, the 97th person died. Both Bland and Devine had suffered irreversible brain damage on the day. The match was abandoned and replayed at Old Trafford in Manchester on 7 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornamental Metal
Ironwork is any weapon, artwork, utensil, or architectural feature made of iron, especially one used for decoration. There are two main types of ironwork: wrought iron and cast iron. While the use of iron dates as far back as 4000 BC, it was the Hittites who first knew how to extract it (see iron ore) and develop weapons. Use of iron was mainly utilitarian until the Middle Ages; it became widely used for decoration in the period between the 16th and 19th century. Wrought iron Wrought ironwork is forged by a blacksmith using an anvil. The earliest known ironwork are beads from Jirzah in Egypt dating from 3500 BC and made from meteoric iron with the earliest use of smelted iron dates back to Mesopotamia. However, the first use of conventional smelting and purification techniques that modern society labels as true iron-working dates back to the Hittites in around 2000 BC. Knowledge about the use of iron spread from the Middle East to Greece and the Aegean region by 1000 BC and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garden
A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both natural and artificial materials. Gardens often have design features including statuary, follies, pergolas, trellises, stumperies, dry creek beds, and water features such as fountains, ponds (with or without fish), waterfalls or creeks. Some gardens are for ornamental purposes only, while others also produce food crops, sometimes in separate areas, or sometimes intermixed with the ornamental plants. Food-producing gardens are distinguished from farms by their smaller scale, more labor-intensive methods, and their purpose (enjoyment of a pastime or self-sustenance rather than producing for sale, as in a market garden). Flower gardens combine plants of different heights, colors, textures, and fragrances to create interest and deli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perimeter Intrusion Detection
A perimeter intrusion detection system (PIDS) is a device or sensor that detects the presence of an intruder attempting to breach the physical perimeter of a property, building, or other secured area. A PIDS is typically deployed as part of an overall security system and is often found in high-security environments such as correctional facilities, airports, military bases, and nuclear plants. Types of PIDS A wide range of intrusion detection technologies exist in the current marketplace. The U.S. Army, as part of their reference material for personnel responsible for planning and executing security programs, divides PIDS technologies into the following categories: * Active IR *Break wire *Electrostatic field *Fence detection (typically a fiber optic, microphonic cable or accelerometer-based sensor mounted on the fence) * Ground motion *Magnetic * Microwave detectors * Near-IR beam break * Passive IR * Ported coaxial cable * Taut wire * Seismic Primary Application A PID ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Security Alarm
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms. Some alarm systems serve a single purpose of burglary protection; combination systems provide Fire alarm system, fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complicated, multirole systems with computer and network surveillance, computer monitoring and control. It may even include a two-way voice which allows communication between the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensor
A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends the information to other electronics, frequently a computer processor. Sensors are used in everyday objects such as touch-sensitive elevator buttons ( tactile sensor) and lamps which dim or brighten by touching the base, and in innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure and flow measurement, for example into MARG sensors. Analog sensors such as potentiometers and force-sensing resistors are still widely used. Their applications include manufacturing and machinery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alarm Device
An alarm device is a mechanism that gives an audible, visual, combination, or other kind of alarm signal to alert someone to a problem or condition that requires urgent attention. Etymology The word ''alarm'' comes from the Old French ''a l'arme'' meaning "to the arms", or "to the weapons", telling armed men to pick up their weapons and get ready for action because an enemy may have suddenly appeared. The word ''alarum'' is an archaic form of ''alarm''. It was sometimes used as a call to arms in the stage directions of Italian ''all'armi'' and appears 89 times in Shakespeare's First Folio">William Shakespeare">Shakespeare's First Folio. Often explained as the off-stage sounds of conflict or disturbance, recent research suggests a bell or drum may have been used to rouse soldiers from sleep. History and development Early alarm devices were often bells, drums, other musical instruments, or any items which made unusual loud noises that attracted the attention of the surroundin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
