Temperature control packaging

When talking about temperature control, what do we mean An example from everyday life is the storage of frozen food like pizza, ice cream, vegetables or others. In many cases, the package indicates the maximum storage time depending on the temperature of storage. If the food is not kept below a certain temperature it often has to be eaten at the day of purchase. 

The last and most advanced system presented in this book includes an array of three MOS-transistor-heated microhotplates (Sect. 6.3). The system relies almost exclusively on digital electronics, which entailed a significant reduction of the overall power consumption. The integrated C interface reduces the number of required wire bond connections to only ten, which allows to realize a low-prize and reliable packaging solution. The temperature controllers that were operated in the pulse-density mode showed a temperature resolution of 1 °C. An excellent thermal decoupling of each of the microhotplates from the rest of the array was demonstrated, and individual temperature modulation on the microhotplates was performed. The three microhotplates were coated with three different metal-oxide materials and characterized upon exposure to various concentrations of CO and CH4. 

The importance of temperature control is significant for laboratory comparisons, accelerated shelf-life studies, and packaging requirements. Also, temperature may be essential when measuring aw levels near critical values, especially for government regulations or critical control points. The precision required in water activity applications will determine the need for temperature control. Several reasons for sample temperature control are ... 

Research purposes. These include studies that examine the effects of temperature on the aw of a sample or follow accelerated shelf life conditions, as well as those that compare the aw of different samples independent of temperature. There are many shelf life, packaging, and isotherm studies in which the added feature of temperature control would be very beneficial. 

The relationship between irradiation flavor intensity and temperature is essentially linear for both packaging methods, except for the temperature of — 140°C. where in both cases the irradiation flavor intensity observed was too high. This suggests that the temperature control system may have failed during the irradiations at this temperature. The flavor scores shown in Table V for a second set of samples (from a different animal) irradiated at —140° and — 196°C. in a subsequent experiment support this suggestion. 

Many investigators are seeking further improvements in the handling of fresh produce. Among methods receiving much attention are the use of postharvest chemicals, retardants of senescence, thermal treatment, controlled atmospheres, new packaging techniques, better temperature control in storage and transit, and irradiation. One method may work well with one fruit or a particular variety of fruit but not with another fruit. 

Packaging the collected samples for shipment (Step 6), a tedious task as it may be, requires a certain level of experience. Improperly packaged samples are often broken in transit insufficient quantities of ice do not provide the proper temperature control—all of these events have a potential to invalidate the collected samples and, in fact, are a common cause for resampling. 

Pure component physical property data for the five species in our simulation of the HDA process were obtained from Chemical Engineering (1975) (liquid densities, heat capacities, vapor pressures, etc.). Vapor-liquid equilibrium behavior was assumed to be ideal. Much of the flowsheet and equipment design information was extracted from Douglas (1988). We have also determined certain design and control variables (e.g., column feed locations, temperature control trays, overhead receiver and column base liquid holdups.) that are not specified by Douglas. Tables 10.1 to 10.4 contain data for selected process streams. These data come from our TMODS dynamic simulation and not from a commercial steady-state simulation package. The corresponding stream numbers are shown in Fig. 10.1. In our simulation, the stabilizer column is modeled as a component splitter and tank. A heater is used to raise the temperature of the liquid feed stream to the product column. Table 10.5 presents equipment data and Table 10.6 compiles the heat transfer rates within process equipment. 

Self-reactive substances need to be subjected to temperature control if their self-accelerating decomposition temperature (SADT) is less than or equal to 55 °C. Test methods for determining the SADT as well as the derivation of control and emergency temperatures are given in the UN Recommendations for the Transport of Dangerous Goods, Manual of Tests and Criteria, Part II, section 28. The test selected shall be conducted in a manner which is representative, both in size and material, of the package. 

The heart of the system is a microreactor packaging scheme that is based upon a commercially available microchip socket. This approach allows the silicon-based reactor die, which contains dual parallel reaction channels with more than 100 electrical contacts, to be installed and removed in a straightforward fashion without removing any fluidic and electronic connections. Various supporting microreactor functions, such as gas feed flow control, gas feed mixing, and various temperature control systems, are mounted on standard CompactPCI electronic boards. The boards are subsequently installed in a commercially available computer chassis. Electrical connections between the boards are achieved through a standard backplane and custom-built input-output PC boards. A National Instruments embedded real-time processor is used to provide closed-loop process control and... 

SEC was performed according to the method of Chin et al. (1994). A Shodex KW802.5 SEC column (Waters Corp., Milford, MA., USA) was used and a Waters liquid chromatography system consisting of the following components was used for the analysis Waters 501 high pressure pump. Waters 717 autosampler, InterAction column temperature control oven, Waters 484 UV/VIS detector, and Waters Millenium 2.0 computer software package. 

NFPA 432, 4.1.3 4.5.1.3 Packages of organic peroxides that require temperature control shall be marked with the recommended storage range. 

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