(Wcsa.world) Cements used in construction are usually inorganic, often lime or calcium silicate based, and can be characterized as being either hydraulic or non-hydraulic, depending upon the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster).
(Wcsa.world) Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a versatile material with many uses, including writing, printing, packaging, cleaning, and a number of industrial and construction processes.
(Wcsa.world) The World Creativity Science Academy (WCSA) on March 16, 2014 organized a ceremony in the city of Faridabad, New Delhi, India to present its Academician Certificates to two professors, each from Vietnam and India.
(Wcsa.world) The plough has been a basic instrument for most of recorded history, although written references to the plough do not appear in English until c. 1100 at which point it is referenced frequently. The plough represents one of the major agricultural inventions in human history.
(Wcsa.world) Among the Four Great Inventions, the magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty (since c. 206 BC), and later adopted for navigation by the Song Dynasty Chinese during the 11th century.
(Wcsa.world) A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill.
(Wcsa.world) Archaeologists have found evidence of man-made glass which dates back to 4000 BC; this took the form of glazes used for coating stone beads. It was not until 1500 BC that the first hollow glass container was made by covering a sand core with a layer of molten glass.
(Wcsas.world) A screw is a type of fastener, sometimes similar to a bolt (see Differentiation between bolt and screw below), typically made of metal, and characterized by a helical ridge, known as a male thread (external thread) or just thread.
(Wcsa.world) The first indications of constructed roads date from about 4000 BC and consist of stone paved streets at Ur in modern-day Iraq and timber roads preserved in a swamp in Glastonbury, England.