Abstract: An apparatus comprising a compact, folded path cell for optical gas detection and/or measurement utilising gas absorption spectroscopy. The apparatus includes a source of electromagnetic radiation, a gas sample cell containing reflective elements, and a detector of electromagnetic radiation. The source and detector are arranged between the reflective elements in an arrangement that reflects the radiation away from the source and detector until the reflected radiation has an adequate optical path length, and then reflects the radiation towards the detector. A spectroscopic analysis can be used to determine the presence and/or to measure at least one parameter of at least one gas species within a gas sample.

Abstract: An apparatus for optical gas detection and/or measurement in an absorption spectroscopy system comprising: a gas cell for containing a gas sample or calibration gas with at least one gas exchange port and at least one optical element for allowing transmission of electromagnetic radiation of a desired wavelength range in and out of the gas cell; and at least one source of converging, diverging or collimated electromagnetic radiation for transmitting electromagnetic radiation through a gas sample contained within the gas cell and towards at least one detector; said detector to monitor absorption of electromagnetic radiation for at least one absorption wavelength or wavelength range associated with at least one gas species, by detecting transmitted electromagnetic radiation that is not absorbed; at least one analyser for analysing an output signal from the at least one detector to measure a parameter of at least one gas species within the gas sample, characterised in that at least one dead volume within the spec

Abstract: An apparatus for use in absorption spectroscopy, comprising: at least one source of electromagnetic radiation for transmitting electromagnetic radiation along an optical path that passes through a gas measurement volume, towards at least one detector; at least one detector to detect the transmitted electromagnetic radiation after passing through the gas measurement volume and to provide an output signal indicative of the detected electromagnetic radiation; and an analyser connected to the at least one detector to receive the output signal and analyse the effects of absorption by at least one gas species within the gas measurement volume for at least one wavelength range of the transmitted electromagnetic radiation, thereby to detect or measure a parameter of the at least one gas species; wherein at least one source or detector comprises a Chip-on-Board (COB) component comprising a solid-state source and/or detector of electromagnetic radiation mounted onto a substrate in a COB configuration.

Abstract: A building system using drywall for interior and exterior wall panels is discussed. A building system using drywall for roof and floor panels is discussed. A building system using drywall which simplifies on site fabrication and construction is discussed. A building system which reduces or eliminates wood in many embodiments is described. Building systems which substantially reduce costs are described.