Environmental testing Temperature-humidity tests

Proper facilities and care for test animals is not only a matter of regulatory compliance (and a legal requirement), but also essential for a scientifically sound and valid study. Husbandry requires clean cages of sufficient size and continuous availability of clean water and food (unless the protocol requires some restriction on their availability). Environmental conditions (temperature, humidity, and light-dark cycle) must be kept within specified limits. All of these must, in turn, be detailed in the protocols of studies. The limits for these conditions are set forth in relevant NIH and USDA publications. 

The purpose of stability testing is to assess the effects of temperature, humidity, light, and other environmental factors on the quality of a drug substance or product. The data produced are used to establish storage conditions, retest periods, shelf loss, and to justify overages included in products for stability reasons. The most useful equation relating temperature and reaction rate is the Arrhenius equation. This equation (27) may be integrated and rewritten as Eqs. (31) and (32). 

PEFC) stacks, components and entire systems, in off-grid, and grid-connected configurations, with a capacity of up to 100 kW electrical power output. The facility consists of an automated and computerised fuel cell test station, gas analysers, a multi-axial vibration system which is housed in a walk-in environmental chamber (for controlling temperatures, humidity, shocks and vibrations) and ancillary equipment. The data obtained are complementary to and validate fuel cell simulations and models with reference to operation modes, components and system characteristics 1 ... 

Military Standard. "Fuze and Fuze Components, Environmental and Performance Tests for MIL-STD-331 (1966 1967) Class 100. Laboratory Tests - Jolt (101) Jumble (102) Forty-Foot Drop (103) Transportation Vibration (104) Temperature Humidity (105) Vacuum Steam Pressure (106) Salt Spray (Fog) (107) Waterproofness (108) Rain Test (Exposed Fuze Storage) (109) Fungus Resistance (110) Five-Foot Drop (111) Extreme Temperature Storage (112) Thermal Shock (113) Rough Handling (Packaged)... 

Other advantages of microfabricated devices include faster response times, and the fabrication of multiple test sites for simultaneous replicate assays in one microfabricated device. This analytical redundancy provides a safeguard that is not easily attained in a conventional macroscale analyzer, where duplicate assays represent the usual extent of repetitive assay of a sample. Encapsulation technology used in the microelectronics industry may also be applicable to microscale devices and could be extended to operations over a wide range of environmental conditions of humidity, and temperature. 

Other factors like feeding conditions (fed or fasted) should be standardized as well. Usually, animals are fasted over night before they are treated. Feeding conditions as well as environmental factors (temperature in the animal room, humidity in the ambient air) can significantly alter the results of the toxicity testing. 

Stability Data Trending. Stability testing provides information about the quality of a drug product under the influence of a variety of environmental factors such as temperature, humidity, and light varying with time... 

The carefully bred strains of animals used for toxicology testing may be much more uniform in their responses, but they are more sensitive to environmental stresses than their wild cousins. Temperature, humidity, and airflow in the animal quarters must be tightly controlled and adjusted to the optimum value for the individual species. Ventilation in the animal rooms should be equivalent to 12 to 15 changes per hour without drafts on the animals. 

This work does not address the fundamental question of mirror corrosion mechanisms. Rather, our study was limited to visual observations of weathering effects upon commercial products exposed to extreme conditions in an environmental test chamber. The principal parameters investigated were 1) the materials ability to protect silvered mirrors from moisture and 2) the effect of mechanical stress (coefficients of expansion mismatches) due to temperature-humidity cycling. 

Artificial weathering was conducted in a Conrad, Inc., Environmental Test Chamber. The chamber was programmed to cycle from -29 C to SO C three times during 24 hours, a cycle consists of a two hour hold at each temperature extreme with a two hour ramp in between. The humidity was measured at 82% at 50 C and 50% at 7 C, thus a distinct freeze-thaw cycle occured when a test passed through 0C ( ) This chamber does not incorporate UV radiation as an environmental stress. 

It is critical to understand that the purpose of stability testing is to provide evidence on how the quality of a drug substance or drug product varies with time under the influence of a variety of environmental factors such as temperature, humidity, and light, and to establish a retest period for the drug substance or a shelf-life for the drug product and recommended storage conditions [3]. 

The adhesion of specimens subjected to environmental exposure tests was evaluated prior to and subsequent to the contact. Wet thermal shock testing consisted of five cycles each for IS minutes in boiling water and 2 minutes in ice water. The maximum transfer time between the two baths was 30 seconds. Thermal and temperature/humidity exposures were performed in controlled atmosphere chambers for 200 hours. Simulated solder tests comprised immersing the test. specimen in a silicone oil followed by solder flotation. The solder temperature varied from 232 to 288 C and the contact time was S or 10 seconds. In some cases, two flotations were performed on the same sample. The effect of a heat treatment at 135 C prior to solder testing was examined the heat treatment time varied from 0 to 16 hours. ... 

Textile membranes are exposed not only to mechanical stresses but also to various environmental influences. The main damaging influences are temperature, humidity, solar irradiation, noxious industrial gases, ozone, dust, salts and micro-organisms. These influences impair the functional properties, performance and life-span of the membranes. DIN EN ISO 4892 standard describes the basics for these tests. It is expected that textile membranes should last for decades without their properties and performance being compromised. However, every year many materials break down due to severe environmental influences and cause damage worth millions of euros. 

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