Abstract: A thermographic sensing device for measuring temperatures at one or more regions of the human body, particularly the breast, utilizes a thermographic composition deposited into linear arrays of recesses formed in the lobes of a conformable medium which is disposable against the skin. The thermographic composition includes a binary solvent system and at least one colorant, wherein the compositions in each array are formulated to melt at precise temperatures, within a diagnostically temperature relevant range, to change from a first visible color to a second visible color.

Abstract: A temperature monitor, a system, and a method monitor temperature on a roof. The temperature monitor includes a base for attaching to the roof, a temperature sensor for detecting changes in temperature, the temperature sensor is attached to the base and positioned periodically on the base, and a roof sensor device attached to the base for transmitting measurement data received from the temperature sensor.

Abstract: A diagnostic coating is applied to the surface of a wellbore service tool. The diagnostic coating has one or more constituents that undergoes an optically-detectable physical change responsive to changing values of one or more downhole parameters. After exposing the diagnostic coating of the service tool to the downhole environment, the tool may be retrieved from the wellbore and inspected to detect any physical change indicative of the service tool having been exposed to elevated values of the one or more downhole parameters.

Abstract: An IC tag in which precision reduction is suppressed and which is compact and manufactured easily, and a manufacturing method of IC tag are provided. The IC tag has: antennas disposed on one surface of a substrate; a capacitor which includes a dielectric and first and second electrodes disposed on one surface of the substrate, and in which an electrostatic capacitance changes irreversibly corresponding to changes in ambient environment; and an IC chip which detects the electrostatic capacitance of the capacitor via a pair of external terminals to which the first and second electrodes are respectively connected, and wirelessly transmits information based on a detection result via the antennas.

Abstract: A sensor system for detecting events is provided. The sensor system includes a sensor and a read-out interface. The sensor includes a transducer and a memory device. The transducer detects an event and generates a sensor signal in response to the event. The memory device includes a floating-gate with a sensing interface coupled to the transducer. The sensing interface has an energy barrier that leaks electrons at a predetermined electron leakage rate through Fowler-Nordheim (F-N) tunneling. The sensor signal alters a geometry of the energy barrier to change the electron leakage rate. The read-out interface is communicatively coupled to the memory device and retrieves data stored on the memory device for analysis. The event and a timestamp of the event are identifiable from the stored data.

Abstract: A printer system includes a memory, a processor, and one or more printer heads. The processor determines a number of transmission layers and a number of barrier layers to use in a color changing expiration indicator based at least in part on a time period between a print date of the indicator and a received expiration date. The printer heads print a reactive layer onto print media, where at least a portion of the reactive layer is configured to migrate through the transmission layers. The printer heads also print the determined number of transmission layers and the determined number of barrier layers in alternation. The printer heads print a reactant layer that is configured to change color responsive to a reaction between the reactant layer and the reactive layer upon migration of the reactive layer through the transmission layers. The reaction is configured to occur on the received expiration date.

Abstract: The present invention relates to a time-temperature indicator (TTI) system suitable for monitoring the time and temperature to which storage sensitive products have been exposed. The TTI system is inexpensive to produce, the response to time and temperature is given in a visually and easily interpretable manner and the visual design is easily adaptable.

Abstract: The present invention relates to a time-temperature indicator for monitoring the quality state of a thermally sensitive article and a monitoring method. The present invention also relates to a preparation method of the time-temperature indicator and a thermally sensitive article using the time-temperature indicator. The time-temperature indicator according to the present invention comprises two laminated layers which are physically separated, i.e. a function indication layer and an adsorption function layer. The two laminated layers are stored and transported separately, and combined together in use. Therefore, the time-temperature indicator of the present invention can be stored and transported at room temperature, which reduces the usage costs of the time-temperature indicator.

Abstract: A time-temperature indicator (TTI) uses polymer hardening properties to “set” or retain indications of temperature history. The TTI includes a mesh layer affixed to a thermo-conductive adhesive layer and a photonic crystal patterned film affixed to the mesh layer. The photonic crystal shows a property of bandgap shift vs temperature and responds to a predetermined range of temperatures to provide a visible indication of the range of temperatures. A hardener pouch is affixed to one end of the mesh layer and releases hardener in response to an initiating event, so that the photonic crystal material responds to the hardener by presenting a fixed state.

Abstract: A defrost indicator including: a body member defining a cavity; two or more fluids, each having one or more of a different composition or characteristic; and wherein when the two or more fluids are exposed to a predetermined temperature, the two or more fluids mix or interact to produce a different composition or characteristic.

Abstract: A defrost indicator including: a body member, at least a portion of which is capable of having a restrained shape or size and an unrestrained shape of size; and an indicia disposed on at least one surface of the body member, an appearance of the indicia being different in the restrained shape or size than in the unrestrained shape or size; wherein the body member is restrained into the restrained shape by freezing one or more liquids associated with the body member.

Abstract: The present disclosure relates to a dosimeter for measuring exposure to heat over time in combination with peak temperature indicators and reversible temperature indicators. The preferred temperature indicator tag is credit card sized and comprises four time-temperature dosimeters. Each dosimeter has a wick in contact with a separate reservoir containing a mix of a colored dye, a wax and an amorphous polymer to indicate a distinct temperature range when the mix melts. The wicks are preferably made of porous paper with a pore size around 8 microns to allow for proper capillary action along its length. An adhesive, except where each wick contacts its respective reservoir and at a vent, preferably seals each wick. The tag preferably has a plurality of peak temperature indicators where each indicator has a blend of a dye, a wax and a polymer for a temperature indication range. The tag also preferably has a plurality of reversible temperature sensors.

Abstract: A method for measuring the real hot-spot temperature in an electric apparatus containing an oil, such as an electric power transformer. The electric apparatus is operated under predetermined and modifiable operating conditions. This method comprises the use of one or several chemical compounds or tracers present and soluble in the oil. Each tracer may transform, at a given temperature, in order to form a residue, such as a soluble gas. From the presence of the residue in the oil, the operator will be able to determine under which predetermined operating condition the hot-spot has been reached and to deduce the hot-spot for a given condition. Among different used compounds, there are diazoic compounds, carbonyl metals, colorants, pigments, liquid crystals and albumins. The method also allows to check the quality of the apparatus on the market and to estimate its life span.

Abstract: A temperature sensing indicator provided with a capsule having a temperature sensing material contained that can be used without being affected by the temperature of fingers and allows the capsule to be easily broken. The temperature sensing indicator irreversibly indicates that a sensed temperature is not lower than a predetermined temperature or not higher than the predetermined temperature when a capsule containing a temperature sensing material is broken. The temperature sensing indicator has a body base made of a plastic material having a recess section formed therein; the capsule contained in the recess and containing the temperature sensing material, an absorbing member mounted on the upper part of the recess, and in which a through hole that exposes a portion of the upper surface of the absorbing member is formed. Pressing the display label crushes the recess in the body base to break the capsule.

Abstract: A release of the frozen solvent trapped inside a solidified gel occurs when the temperature increases, followed by a dissolving of a reactive substance present in a membrane that is located in direct physical contact with the gel, resulting in the reabsorption of the reactive substance dissolved in the solvent into the solid gel layer within a constant time. In this manner, the components generating color change come together within the solid gel layer initiating a reaction to change the color of the indicator layer. Thus, the increase in temperature above a melting point of the solid gel layer is enough to activate the intelligent label with an irreversible color change.

Abstract: A temperature-activatable time-temperature indicator that can be used to monitor the historical exposure of a host product to ambient temperatures includes an optically readable, thermally sensitive indicator element. The indicator element can be inactive below a base temperature and is intrinsically thermally responsive at or above an activation temperature which is equal to or greater than the base temperature. The indicator can record cumulative ambient temperature exposure above the activation temperature irreversibly with respect to time. The indicator element can include a synthetic polymeric material, and optionally, a dye. A side-chain crystallizable polymer such as poly(hexadecylmethacrylate), that is solid below the base temperature and is a viscous liquid above the activation temperature can be employed. Intense indicator element colors can be obtained using an appropriate dye or dyes. Various structural configurations of indicator are described and illustrated.

Abstract: Indicator inks, indicators formed by printing or otherwise utilizing the inks and host products utilizing the indicators are disclosed. Reactivity-enhancing adjuvants stimulate enhanced thermal reactivity of diacetylenic or other indicator agents capable of responding to ambient thermal conditions with a visual change signaling an end point. The diacetylenic or other agents may be sensitive or relatively insensitive to ambient temperatures. Use of a reactivity-enhancing adjuvant provides a useful means for adapting the reactivities of indicator agents to the response characteristics of prospective host products, for example perishables such as vaccines or fresh fish and maturables such as fruit, cheese and wine. Some exemplary adjuvants include low-temperature polymerization initiators, for example methyl ethyl ketone peroxide and polymerization accelerators, for example cobalt compounds. Such initiators and accelerators can also be used in combination.

Abstract: An improved quality assurance system and method for point-of-care testing are disclosed. The present invention provides quality assurance for laboratory quality tests performed by a blood analysis system or the like at the point of patient care without the need for running liquid-based quality control materials on the analysis system. Quality assurance of a quantitative physiological sample test system is performed without using a quality control sample by monitoring the thermal and temporal stress of a component used with the test system. Alert information is generated that indicates that the component has failed quality assurance when the thermal and temporal stress exceeds a predetermined thermal-temporal stress threshold. Alternatively, the present invention provides quality assurance for laboratory quality tests performed by a blood analysis system or the like at the point of patient care by minimizing the need for running liquid-based quality control materials on the analysis system.

Abstract: A low temperature history indication plate 31 made of a low thermal expansion material used within an apparatus is provided on the outer surface of the apparatus. A surface of the low temperature history indication plate 31 is mirror polished. Simply by observing the low temperature history indication plate 31, it can be determined whether or not martensitic transformation has occurred.

Abstract: A method is provided for determination of an operating temperature in a thermally highly loaded device. Multiple individual passive measurement elements, having a measurable physical parameter depending on a constant temperature set during heat treatment, are provided. The parameter is set differently for each of the different measurement elements which are combined to form an array. In a first measurement, values of the physical parameter for the array are determined before the array is subjected to the operating temperature. The array is subjected to the operating temperature in the device and in a second measurement, values are determined for all the measurement elements in the array. First and second measurement values of the physical parameter for each of the measurement elements are compared and the temperature of the heat treatment of that measurement element whose value of the physical parameter has changed the least is taken as the measured temperature.

Abstract: The present invention provides a thermal history sensor having a plurality of substrates positioned adjacent to an item. The substrates include different compositions, such that the substrates respond to thermal exposures with different changes in electrical conductivity or magnetic permeability. By measuring the electrical or magnetic properties of the substrates following thermal exposure, information about the thermal history may be obtained.

Abstract: The present invention relates to a stimulus-indicating device. More particularly, the present invention relates to an apparatus for evidencing when a stimulus sensitive product has been exposed to a designated or predetermined stimulus for a certain period of time, and the invention relates to a method for manufacturing aspects of that apparatus.

Abstract: The invention provides an indicator excellent in constitutional simplicity and capable of indicating both the temperature of an article to be indicated and elapsed time at that temperature, as well as an indicator of simple constitution capable of indicating the level of deformation of the article by external force. Disclosed is an external stimulus indicator including a polymer composition composed of a polymer and a dye, wherein the polymer composition has the dye fixed in a specific molecular dispersion state in the polymer, and when kept at a temperature not lower than a specific temperature for at least a predetermined time or deformed to at least a certain level by external force, changes its color to a hue different from the initial hue thereof.

Abstract: Freeze indicators can include an indicator dispersion, a liquid medium, indicator particles dispersed in the liquid medium and a particulate inorganic nucleating agent to inhibit supercooling of the liquid medium. The inorganic nucleating agent can have an ionic surface coating which can help provide a sharp end point. Optionally, freeze indicators can include indicator particles comprising an organic material and a softener to soften the indicator particles and provide the freeze indication with an enhanced visual appearance. Another option is to provide a temperature-sensitive stabilizer to inhibit coagulation of the indicator dispersion at temperatures above the liquid medium frozen state melting point while permitting coagulation of the indicator dispersion at the liquid medium frozen state melting point.

Abstract: A freeze indicator can include an indicator dispersion having an aqueous liquid medium and organic material indicator particles dispersed in the aqueous liquid medium. The indicator dispersion can have an initial appearance before freezing and an irreversibly different appearance after freezing and can exhibit a freeze-onset temperature of about ?1.9° C. or higher. Some factors helpful to providing a relatively high freeze onset temperature are employment of a proteinaceous ice-nucleating agent, control of pH, use of a protein stabilizer and control of the ratio of protein stabilizer to ice-nucleating agent.

Abstract: Temperature-sensitive films that undergo an irreversible change in appearance when the films are heated to a threshold temperature are provided. Also provided are methods for indicating that an object in thermal contact with a temperature-sensitive film has reached a threshold temperature.

Abstract: To provide a temperature-sensitive indicator which, when using the temperature-sensitive indicator having a capsule packed with a heat-sensitive material, enables easy rupture of the capsule, without being affected by the temperature of a finger of a user. The indicator includes: a base; a concave portion formed in the base; a capsule accommodated in the concave portion and packed with a heat-sensitive material; an absorbing member placed on the capsule; pressing means which is arranged above the absorbing member, and which is formed of a transparent heat insulating material; and a cover which covers at least the capsule and the absorbing member. By pressing on the capsule using the pressing means 6, the capsule is ruptured.

Abstract: An indicator composition for determining a thermal or chronological history during shipping or storage of a product. The composition includes a plurality of nanoparticles dispersed throughout a matrix. The nanoparticles turn color while dispersed in the matrix as a function at least one of time and temperature.

Abstract: Indicator devices and systems are provided. Indicator devices include a sleeve, a dome-like transparent member, a connector body, and an indicator. In alternate embodiments, indicator devices include a sleeve and an indicator retained in the sleeve by a retaining ring and a latch held in place by a spring. Indicator systems include an indicator device coupled to an enclosure containing critical equipment.

Abstract: A system and method are disclosed for controlling an inventory of point-of-care diagnostic devices. The inventory includes a main inventory and at least one subinventory. Each device has an ambient temperature shelf life. Data associated with the devices is entered, including: the current quantity and predetermined minimum quantity of devices in the main inventory; and the current quantity and predetermined minimum quantity of devices in the subinventory. A first timestamp is associated with each device when the device is transferred from the main inventory to the ambient temperature subinventory. The first timestamp is compared to a second timestamp prior to use of the device to determine whether the device's ambient temperature shelf life is exceeded. The current quantity of devices in the subinventory is updated in response to an event that causes a change in the current quantity of devices in the subinventory.

Abstract: A label for indicating a history of high-temperature exposure includes an internal substance and an external substance surrounding the internal substance. The internal substance and the external substance may be separated into respective frozen solid bodies at low temperatures, the internal and external substances having colors that are different from each other, and at least one of the internal substance and the external substance may convert to a liquid phase and the internal and external substances may be naturally mixed when the substances are exposed to high temperatures higher than the low temperatures for a predetermined amount time, and indicate the history of high temperature exposure without being restored to the initial forms of their frozen solid bodies even when refrozen or re-cold stored.

Abstract: Freeze indicators providing a visual indication of exposure of the freeze indicator to a freezing or near-freezing temperature and their manufacture are disclosed. The freeze indicators employ colloidal dispersions as active elements and include flexible freeze indicators, freeze indicators protected against drying out and freeze indicators employing core shell composites, for example gold coated pigments as active indicator elements. Also disclosed are: a combination freeze indicator and threshold temperature indicator; a combination threshold indicator and cumulative temperature indicator; and three-way combination indicators that can provide indications of cumulative past temperature exposure, exposure to freezing temperatures and exposure to a temperature above a threshold.

Abstract: A timing device for indicating a passage of a duration of time is disclosed. The timing device in accordance with the embodiments of the invention has a grid array architecture. The grid array architecture includes an electrode structure with an anode layer, a cathode layer and a thermistor layer. The anode layer and the thermistor layer are electrically coupled through a plurality of cathode line structures. In operation the timing device is actuated through a suitable mechanism to initiate depletion of the anode layer and, thereby, indicate a passage of a duration time. As the anode layer depletes, sequential cathode line structures are exposed and the thermistor layer acts as a variable resistor through a plurality of exposed cathode line structures.

Abstract: A method and apparatus for an irreversible temperature sensor for measuring a peak exposure temperature. The apparatus is fabricated by printing an admixture of conductive nanoparticles on a dielectric substrate to form a film. The film has an electrical resistance that is inversely proportional to the exposure temperature. The electrical resistance also irreversibly decreases as the exposure temperature of the film increases. A portion of the film is exposed to a pulse of electromagnetic energy sufficient to render it substantially more electrically conductive than the portion that was not exposed. In use, the peak exposure temperature is determined by measuring the electrical resistance of the non-altered portion of the film and the electrical resistance of the portion that was exposed to the pulse of electromagnetic energy, and subtracting the electrical resistance of the altered portion from the electrical resistance of the portion that was not altered, to provide a difference value.

Abstract: The invention relates to an activation of temperature time monitors (1), particularly for perishable products, such as medications, vaccines, stored blood, or food products, wherein the monitor (1) contains at least one electrical circuit (4-6), which is mechanically activateable/changeable, characterized in that the monitor (1) is activatable by means of an irreversible mechanical interruption of an electrically conductive connection (8) of the at least one electrical circuit (4-6), or that the monitor (10) is activatable by means of an irreversible mechanical removal of an electrically conductive area (15) of the at least one electrical circuit (16, 17). The invention is based on the object of improving an activation of temperature time monitors in such a way what it is particularly cost effective and reliable, and that an automated activation is possible.

Abstract: A system and method for indication of temperature exposures beyond a set of predetermined limits employs the salts of weak acid-strong base or of a strong acid-weak base compound as reactants. A device includes a housing and capsule. A first reactant and a liquid are included within the capsule. The liquid is chosen such that it expands upon freezing. The capsule is sized such that when the liquid freezes and expands, the capsule fractures. A second reactant is provided within the housing. The location of the second reactant and the method of attaching (if any) the second reactant to the housing may take various forms. When the liquid within the capsule freezes, it expands and fractures the capsule. Upon thawing, the reactant within the capsule escapes and mixes with the reactant located outside the capsule. A second embodiment is a time-temperature indicator. A flexible housing is used, allowing the user to manually deform the housing to fracture a capsule enclosed therein.

Abstract: Indicator devices and systems are provided. Indicator devices include a sleeve, a dome-like transparent member, a connector body, and an indicator. In alternate embodiments, indicator devices include a sleeve and an indicator retained in the sleeve by a retaining ring and a latch held in place by a spring. Indicator systems include an indicator device coupled to an enclosure containing critical equipment.

Abstract: Washers partially coated with a thermochromic material are incorporated into bolted electrical connections to monitor or record temperature changes undergone by the electrical connections as indications of the performance or integrity of the electrical connections. For monitoring ongoing performance, the color changes undergone by the thermochromic coated washers can be compared to each other within a common field of view or to a common datum, such as a nearby thermochromic coated washer mounted in a bolted non-electrical connection. Irreversible thermochromic materials can be used to record elevated temperature events such as approaching or reaching a design temperature limit or a fault condition. Different thermochromic materials can be combined within the same washers to monitor different ranges of temperature or to record multiple threshold events.

Abstract: The present invention relates to an over temperature alarm indication apparatus. In order to solve the problem of high cost in the prior art, the apparatus in the present invention comprises a first sealed and transparent container with fixed cubage and a second sealed and transparent container with variable cubage. Said first container and second container are connected through a thin tube, and a certain amount of liquid is filled in said thin tube; alarm indication material for generating color changing effects upon receiving liquid from said thin tube is provided in said first and second container; wherein the change of the environment temperature will cause the air in said first and second container to expand and shrink, and thus move said liquid in said tube.

Abstract: A freeze indicator employs, as active indicator element, dispersion of solid particles in a liquid medium which can be water or aqueous and which coagulates to provide an irreversible appearance change when subject to freezing. The liquid dispersion can be contained in an indicator volume around which extends a vapor block layer. The vapor block layer can prevent loss of liquid vapor from the dispersion and consequent drying out and dysfunctionality of the freeze indicator. For containing an aqueous medium, bilayer and trilayer laminate materials can be used which have a low water vapor transmission rate. The active indicator element can be a dilute colloidal dispersion of a metal such as gold or silver or other inorganic pigment material in water or an aqueous medium. Some embodiments avoid use of dispersants and the like and employ an active indicator element consisting of inorganic pigment particles, water and optionally an ice nucleating agent.

Abstract: A temperature-history sensor includes a resonance circuit composed of at least a capacitor and a coil. The temperature-history sensor has a display for indicating a predetermined set temperature of the temperature-history sensor. The capacitor has at least a thermofusion material between electrodes of the capacitor, and the melting point of the thermofusion material is in the region of the set temperature.

Abstract: Freeze indicators providing a visual indication of exposure of the freeze indicator to a freezing or near-freezing temperature and their manufacture are disclosed. The freeze indicators employ colloidal dispersions as active elements and include flexible freeze indicators, freeze indicators protected against drying out and freeze indicators employing core shell composites, for example gold coated pigments as active indicator elements. Also disclosed are: a combination freeze indicator and threshold temperature indicator; a combination threshold indicator and cumulative temperature indicator; and three-way combination indicators that can provide indications of cumulative past temperature exposure, exposure to freezing temperatures and exposure to a temperature above a threshold.

Abstract: An excess temperature indicator can provide a visual indication of past exposure of perishable, maturing and other host products to an elevated temperature exceeding a threshold temperature. The indicator can have an upper layer provided with a viewing window and a wick attached to the upper layer. A reservoir of heat-fusible indicator material can be disposed in contact with the wick, to fuse and move along the wick changing the visual appearance of a first portion of the wick viewable through the window, in response to an excess temperature event. Also, the indicator can have a region of fused upper layer material attaching the wick to the upper layer. Optionally, a window seal can extend around the viewing window to prevent migration of the indicator material. The indicator can be employed to monitor vaccines, foods and other products providing an enduring visual signal of exposure to potentially damaging temperature conditions.

Abstract: A combination temperature exposure indicator suitable for attachment to, or association with, a host product has a substrate, a freeze indicator supported by the substrate and a cumulative ambient time-temperature indicator also supported by the substrate. The freeze indicator can provide a visual indication of exposure of the freeze indicator to a freezing or near-freezing temperature and the cumulative time-temperature indicator can provide a visual indication of exposure of the cumulative time-temperature indicator to a predetermined cumulative time-temperature value. Also disclosed are: a combination freeze indicator and threshold temperature indicator; a combination threshold indicator and cumulative temperature indicator; and three-way combination indicators that can provide indications of cumulative past temperature exposure, exposure to freezing temperatures and exposure to a temperature above a threshold.

Abstract: A temperature-history sensor includes a resonance circuit composed of at least a capacitor and a coil. The temperature-history sensor has a display for indicating a predetermined set temperature of the temperature-history sensor. The capacitor has at least a thermofusion material between electrodes of the capacitor, and the melting point of the thermofusion material is in the region of the set temperature.

Abstract: Taught is a residual lifetime indicator for perishable consumer products, comprising a material which displays a property variable with varying temperature in accordance with a given function, actuating means which act on the material so as to make it exhibit the aforesaid property, and indicator means linked to the material/actuating means combination, the indicator means indicating the residual lifetime relative to the expiry date of the product; the material is a fluid (102; 114) of viscosity variable as a function of the temperature, which flows in a pipe (2, 212; 4, 134) having a given cross-section, the actuating means comprising a device (311, 601, 411, 701; 313, 203, 113, 204) capable of applying an essentially constant pressure on said fluid (102, 114), the flow of said fluid being linked to said indicator means (701, 413).

Abstract: It's a device whose purpose is to monitor the storage and indicate that a frozen product has been subjected to a thermal variation, with temperature rise, causing the fusion and liquefaction of a fluid (H) contained in the indicator. The indicator comprises a hollow, cylindrical tube (2) with an open end (3), featuring a releasable cap (17) and a closed end (4), with a slidable piston (5) inside the tube (2). A compartment (C1), inside the tube (2), placed between the piston (5) and the end (4), is fulfilled with a compressed means like a fluid (0)/spring (M), and a compartment (C2) placed between the piston (5) and the end (3), is fulfilled with the fluid (H), frozen, in the solid state. Upon the thawing of the product, the fluid (H) also thaws, escaping the compartment (C2) and allowing the movement of the piston (5), pushed by the fluid (0). The movement of the piston (5) is irreversible and constitutes the indicator's visual indication revealing that the product has been thaw.

Abstract: A thermal history indicator comprising a temperature sensitive material, a sensing device, a heat insulating material functioning to buffer the temperature sensitive material against temperature change, and an activation means. The triggering of the activation means allows a molten phase of the temperature sensitive material to interact with the sensing device, or cease interacting with the sensing device, thereby altering its chemical, biochemical or microbiological.

Abstract: A freeze indicator employs, as active indicator element, dispersion of solid particles in a liquid medium which can be water or aqueous and which coagulates to provide an irreversible appearance change when subject to freezing. The liquid dispersion can be contained in an indicator volume around which extends a vapor block layer. The vapor block layer can prevent loss of liquid vapor from the dispersion and consequent drying out and dysfunctionality of the freeze indicator. For containing an aqueous medium, bilayer and trilayer laminate materials can be used which have a low water vapor transmission rate. The active indicator element can be a dilute colloidal dispersion of a metal such as gold or silver or other inorganic pigment material in water or an aqueous medium. Some embodiments avoid use of dispersants and the like and employ an active indicator element consisting of inorganic pigment particles, water and optionally an ice nucleating agent.

Abstract: An excess temperature indicator can provide a visual indication of past exposure of perishable, maturing and other host products to an elevated temperature exceeding a threshold temperature. The indicator can have an upper layer provided with a viewing window and a wick attached to the upper layer. A reservoir of heat-fusible indicator material can be disposed in contact with the wick, to fuse and move along the wick changing the visual appearance of a first portion of the wick viewable through the window, in response to an excess temperature event. Also, the indicator can have a region of fused upper layer material attaching the wick to the upper layer. Optionally, a window seal can extend around the viewing window to prevent migration of the indicator material. The indicator can be employed to monitor vaccines, foods and other products providing an enduring visual signal of exposure to potentially damaging temperature conditions.