U
U-factor The U-factor or "U-value", is the overall
heat transfer coefficient that
describes how well a building element conducts heat or the rate of transfer of
heat (in watts) through one square metre of a structure divided by the
difference in temperature across the structure. The elements are commonly
assemblies of many layers of components such as those that make up
walls/floors/roofs etc. It measures the rate of heat transfer through a
building element over a given area under standardised conditions. The usual
standard is at a temperature gradient of 24 °C (75 °F), at 50% humidity with no wind (a smaller U-factor is better at reducing heat transfer).
It is expressed in watts per metres squared kelvin, or W/m²K. This means that
the higher the U value the worse the thermal performance of the building
envelope. A low U value usually indicates high levels of insulation. They are
useful as it is a way of predicting the composite behaviour of an entire
building element rather than relying on the properties of individual materials.
Unidirectional Externality These are externalities in which the external costs or benefits of the resource use are 'one way'.
Urban acupuncture
Surprisingly exactly
what it sounds like: the intersection of urban design and traditional Chinese
acupuncture. Consists of targeting small areas to relieve the stress of the
overall city and listening to chanting music while trying to ignore the fact
that thousands of needles are being stabbed into your body.
Urban Airshed Model (UAM): Urban Airshed Model (UAM): A three-dimensional grid-based photochemical computer model of the production of ozone from precursors (VOCs and NOx) and the dispersion of air pollution in a specific geographic area over a period of one or two days.
Urban biodiversityUrban
biodiversity is the variety and richness of living things, including genetic,
species and habitat diversity found in and on the edge of cities.
Urban compactionThe process that aims to increase built area and residential population densities; to intensify urban economic, social and cultural activities and to manipulate urban size, form and structure and settlement systems in search of the environmental, social and global sustainability benefits that can be derived from concentration of urban functions.
Urban Fabric Urban fabric is the physical structure of an urban area.
Urban FabricThis refers to the manner in which urban tissues, either uniform or diverse in nature are knitted together with the urban structure to form an entity.
Urban FormIt is the collective three dimensional expression of an urban area as represented by their relationship to each other. The term built would refer to buildings, city wall, vertical towers, flyovers etc, while open spaces would include streets, courtyards, roads, parks, tot-lots, river beds etc. Size shape, grain and texture of an area are some of the characteristics which determine the nature of urban form.
Urban Form Urban Form means the physical form of an urban area consisting of street patterns, building sizes and shapes, architecture, and density.
Urban Heat Island Urban areas being warmer then the surrounding rural area. Ordinarily a nocturnal phenomenon.
Urban Heat Island Effect The Urban Heat Island Effect is a measurable increase in ambient urban air temperatures resulting from the replacement of vegetation with buildings, roads and other heat absorbing infrastructure. The heat Island effect can result in significant temperature differences between urban and rural areas.
Urban MorphologyThe three dimensional form of a group of building and the
spaces they create.
Urban Open SpacesOpen spaces in urban areas used for performing different
outdoor activities like movement, recreation, relaxation, play etc.
Urban prairie
Urban land that has
reverted to green space. For those of us that live outside America, it conjures
up a vague image of green fields and blonde little girls in bonnets.
Urban renewal planA measure of the balance between shear stress and shear strength in a slope; a state of limiting equilibrium exits when shearing forces equal resisting forces in a slope and F=1
Urban resilienceA city’s ability to cope with, and adapt to, natural disasters and changing circumstances.
Urban Street Canyon The
space delimited by the street and the facades of the building outdoor
activities along the street.
UrbanizationA process of migration of people that results in population increase in cities with increased urban area and population density.
Urbicide
Not quite as scary as
other -cide words (but possibly worse if you’re an architect), it means
“violence against the city.”
URDPFI URDPFI
Urban and Regional Development Plans Formulation and
Implementation (URDPFI)