A wearable pollutant indicator, methods of making and using same. The indicator includes a polymeric film substrate having a first side and a second side, an adhesive disposed on the first side of the substrate, and a readily understood user interface disposed on the second side of the substrate, wherein the user interface comprises a qualitative indicator of the accumulated exposure to incident airborne particulate pollution as sensed through the reaction of the transition metal oxides therein.

A wearable pollutant indicator, methods of making and using same. The indicator includes a polymeric film substrate having a first side and a second side, an adhesive disposed on the first side of the substrate, and a readily understood user interface disposed on the second side of the substrate, wherein the user interface comprises a qualitative indicator of the accumulated exposure to incident airborne particulate pollution as sensed through the reaction of the transition metal oxides therein.

Among other things, this application describes systems and methods for detecting gas using a wide band light source, and at least two narrow band light sensors, wherein each sensor may be operable to detect light at a different range of wavelengths. Additionally, the gas detector device may comprise a color changing indicator operable to react with gas in the air to change color, wherein different gases may react to create different colors, and wherein the sensors detect light reflected by the color changing indicator from the wide band light source. The gas detector device may comprise a processor in communication with the at least two light sensors operable to receive detected reflected wavelength information from the light sensors, and determine the type of gas that reacted with the color changing indicator based on the color detected by the sensors, wherein each color may be associated with a different type of gas.

The invention relates to a method for measuring the concentration of a gas component in an atmosphere of a packaging which is made from a plastic film and which comprises a gas concentration indicator substance on the side of the plastic film facing the atmosphere.

A chemical indicator strip for detecting disinfectant that includes a film substrate, and an indicator portion with a first and a second ink. The first and the second ink can react in the presence of a threshold level of disinfectant for a threshold level of exposure time. The chemical indicator strip can be used in a method of detecting a threshold level of disinfectant. The method can include exposing a chemical indicator strip to a concentration of disinfectant for a preset amount of time. The method can include providing a visual indicator to a user that changes from a first color to a second color. The method can indicate that the chemical indicator strip has been exposed to a threshold concentration of disinfectant for a threshold amount of time when a complete color change occurs on the chemical indicator strip from the first color to the second color.

An activatable print medium is disclosed. The print medium includes a first reactive component, a second reactive component, wherein the first and second reactive components are configured to react to initiate a state change of the activatable print medium when exposed to each other and a barrier that is initially in an unactivated form and configured to transition to an activated form when activated by an application of at least one of an activation heat and an activation pressure wherein after the barrier is activated, but not before, the activatable print medium is configured so that the first and second reactive components interact in response to a predetermined environmental stimulus or interact over time at a rate dependent on an environmental stimulus, thereby providing an indication of the cumulative historical exposure of the activatable print medium to the environmental stimulus.

An activatable print medium is disclosed. The print medium includes a first reactive component, a second reactive component, wherein the first and second reactive components are configured to react to initiate a state change of the activatable print medium when exposed to each other and a barrier that is initially in an unactivated form and configured to transition to an activated form when activated by an application of at least one of an activation heat and an activation pressure wherein after the barrier is activated, but not before, the activatable print medium is configured so that the first and second reactive components interact in response to a predetermined environmental stimulus or interact over time at a rate dependent on an environmental stimulus, thereby providing an indication of the cumulative historical exposure of the activatable print medium to the environmental stimulus.

The invention relates to a polymeric indicator fixed in a polymeric gel carrier, wherein the polymeric gel carrier comprises a hydrophilic polymer, wherein the polymeric indicator and the hydrophilic polymer are present together in the form of a combined cross-linked hydrogel network fixed by chemical bonds.

The invention further relates to a method for preparing a polymeric indicator fixed in a polymeric gel carrier and to a sensor for measuring pH, which comprises the polymeric indicator fixed in a polymeric gel carrier.

A kit for colorimetric identification of one or more cannabinoid compounds is disclosed. The kit includes at least two cannabinoid sensitive visualization reagents and a colour reference chart that may have at least two discernable colours, A method is also provided for colorimetric identification of one or more cannabinoid compounds in a liquid sample. The method includes contacting the liquid sample separately with at least two cannabinoid sensitive visualization reagents; allowing the at least two cannabinoid sensitive visualization reagents to develop for a defined amount of time; and comparing the resulting colour change of the at least two cannabinoid sensitive visualization reagents to a colour reference chart.

This disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and methods of sensing metal ions using three-dimensional printed ion sensors. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent and an ion-sensing agent. The fusing agent can include water and an electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation energy and convert the radiation energy to heat. The ion-sensing agent can include water and a redox-active inorganic salt.