Abstract: There is described an indicator device for indicating the passage of time, the indicator device comprising an indicator section and a barrier section adjacent thereto, said indicator section comprising: an indicator material; a substrate material; and a first adhesive layer; the indicator material and the substrate material being in the form of one or more layers; the indicator material displaying different visible properties in response to the presence or absence of a chemical agent and/or the concentration thereof; the barrier section comprising a removable barrier layer, the removable barrier layer being substantially impermeable to the chemical agent; wherein on removal of the removable barrier layer, the concentration of the chemical agent in the indicator section changes over time, effecting a visible change. The device may be used to detect the presence/absence of oxygen, water, carbon dioxide, an amine, ammonia, and/or carboxylic acids or to indicate the passage of time.

Abstract: There is described an indicator device for indicating the passage of time, the indicator device comprising an indicator section and a barrier section adjacent thereto, said indicator section comprising: an indicator material; a substrate material; and a first adhesive layer; the indicator material and the substrate material being in the form of one or more layers; the indicator material displaying different visible properties in response to the presence or absence of a chemical agent and/or the concentration thereof; the barrier section comprising a removable barrier layer, the removable barrier layer being substantially impermeable to the chemical agent; wherein on removal of the removable barrier layer, the concentration of the chemical agent in the indicator section changes over time, effecting a visible change. The device may be used to detect the presence/absence of oxygen, water, carbon dioxide, an amine, ammonia, and/or carboxylic acids or to indicate the passage of time.

Abstract: Embodiments of the present invention include methods and apparatus for dynamically controlling pressure within a wellbore while forming the wellbore. In one aspect, one or more pressure control apparatus are used to maintain desired pressure within the wellbore while drilling the wellbore. In another aspect, pressure is dynamically controlled while drilling using foam to maintain a substantially homogenous foam flow regime within the wellbore annulus for carrying cuttings from the wellbore.

Abstract: A chemical indicator having a particulate inorganic substrate, and at least one reactive dye or ink coated on and/or impregnated within the particulate inorganic substrate. Coating and/or impregnating at least one reactive dye or ink on or within a particulate inorganic substrate improves the storage stability and/or thermal stability of the at least one reactive dye or ink, which typically includes relatively unstable compounds. This allows the present indicators to be incorporated into thermoplastic polymer materials and processed conventionally while maintaining the efficacy and stability of the new indicators. The indicators provide simple, reliable, and cost effective detection means for detecting analytes such as ammonia, carbon dioxide, and oxygen, and may find use in applications such as food packaging and medical applications.

Abstract: A chemical indicator or ink, and methods for manufacture thereof, comprises at least one carbon dioxide-sensitive reactive dye which is capable of detecting changes in carbon dioxide concentration in a fluid under fluid and/or gas phase pressure of carbon dioxide above approximately (1) bar. The present chemical indicators or inks are useful in the monitoring of relatively high carbon dioxide pressure environments, such as in carbonated drinks. The present invention also relates to containers for holding a carbonated liquid, and closures therefore, comprising a carbon dioxide indicator or a carbon dioxide-sensitive ink, wherein the carbon dioxide indicator and/or the ink comprises at least one carbon dioxide-sensitive reactive dye which is capable of detecting changes in carbon dioxide concentration in a fluid under fluid and/or gas phase pressure of carbon dioxide above approximately (1) bar.

Abstract: A chemical indicator comprises a particulate inorganic substrate, and at least one reactive dye or ink coated on and/or impregnated within the particulate inorganic substrate. Coating and/or impregnating at least one reactive dye or ink on or within a particulate inorganic substrate improves the storage stability and/or thermal stability of the at least one reactive dye or ink, which typically comprises relatively unstable compounds. This allows the present indicators to be incorporated into thermoplastic polymer materials and processed conventionally while maintaining the efficacy and stability of the new indicators. The indicators provide simple, reliable, and cost effective detection means for detecting analytes such as ammonia, carbon dioxide, and oxygen, and may find use in applications such as food packaging and medical applications.

Abstract: Embodiments of the present invention include methods and apparatus for dynamically controlling pressure within a wellbore while forming the wellbore. In one aspect, one or more pressure control apparatus are used to maintain desired pressure within the wellbore while drilling the wellbore. In another aspect, pressure is dynamically controlled while drilling using foam to maintain a substantially homogenous foam flow regime within the wellbore annulus for carrying cuttings from the wellbore.