Test chambers relative humidity

Besides the mentioned tests, calculation of the shrinkage coefficient following Equation 1 demands additional ESEM tests to be performed. The procedure would be to save several digital images (not just one as was done in the previous experiments) during the equilibrium time at every relative humidity (chamber relative humidity equals relative humidity of CP sample), in a number of sequential steps, in order to relate deformations and drying time. 

Corrosion-resistance test This can be done with the help of a salt spray test. The test piece is suspended in a salt spray chamber (Figure A13.6) for. seven days in 100% relative humidity (IS 101 and IS 11864). After the test, the surface should have no signs of deterioration or corrosion. 

Permeability of an FML is evaluated using the Water Vapor Transmission test.28 A sample of the membrane is placed on top of a small aluminum cup containing a small amount of water. The cup is then placed in a controlled humidity and temperature chamber. The humidity in the chamber is typically 20% relative humidity, while the humidity in the cup is 100%. Thus, a concentration gradient is set up across the membrane. Moisture diffuses through the membrane, and with time the liquid level in the cup is reduced. The rate at which moisture is moving through the membrane is measured. From that rate, the permeability of the membrane is calculated with the simple diffusion equation (Fick s first law). It is important to remember that even if a liner is installed correctly with no holes, penetrations, punctures, or defects, liquid will still diffuse through the membrane. 

A small 3 cm x 3.5 cm section of the catalyst-coated desiccant wheel (25 cm diameter) was cut and placed in specially made holder shown in Fig. 12.9-6a. The piece of sample was tested in a 0.2 m3 environmental chamber at Chiaphua Industries Ltd. (Fig. 12.9-6b) for reduction of airborne VOC. The chamber was filled with the target VOCs through two stage saturators shown in Fig. 32b. Once the VOC level in the chamber stabilized, the fan was turned on to circulate the air through the sample. Three sets of sensors were located at the inlet and outlet of the holder, as well as in the center of the chamber. The chamber temperature and relative humidity were kept constant during the test. Figure 12.9-6c shows the results for VOC levels of 4000, 2000 and 1000 ppb at room temperature. The reduction rate was slower because of the low VOC concentration and the poor air circulation in the chamber. Also unlike the Prototype Unit, the catalyst was kept at room temperature throughout the test. 

Wedge Test. The adhesive bond durabilities of the Inhibitor-treated 7075-T6 surfaces were evaluated by wedge tests (ASTM D-3762) on bonded specimens using the FM 123-2 epoxy adhesive to simulate the epoxy primer. The specimens were placed In a humidity chamber at 65°C and 95% relative humidity and removed at specified time Intervals to record the crack tip locations after each examination, they were returned to the humidity chamber. 

Coal-dust test. 1500 g coal-dust is uniformly scattered on the four shelves fixed to the walls of the explosion chamber of the gallery, and stirred by the air current produced by a fan. One minute after stopping the fan, the charge is fired. Relative humidity in the explosion chamber is kept below 80%. The test is repeated five times under the same conditions as those in the methane test. No ignition should occur. 

Shortly before exposure to the test chemical, the animals are weighed and exposed to different test chemical concentrations in the designated chamber for 4 hours. The temperature at which the test is performed should be maintained at 22 °C ( 2°C). Ideally, the relative humidity should be maintained between 30% and 70%, but in certain cases (e.g., aerosols), even this may not be practicable. Food should be withheld during exposure. Water also may be withheld in certain cases. The observation period for acute inhalation toxicity in animals should be at least 14 days. For clinical examination and pathology, the parameters listed for acute oral toxicity may be followed. The following conditions should be monitored during the experiment using a standard inhalation chamber. 

Both for TLC and for HPTLC pre-coated plates silica gel 60 the best results were obtained with a solvent mixture consisting of cyclohexane and chloroform in a ratio of 65/35 by volume, with a 5 cm migration distance for HPTLC plates and a 7 cm migration distance for the TLC plates. In both cases the plates were adjusted prior to use to 20 relative humidity and were developed in normal chambers without chamber saturation. For both types of plates, 0.75 pi quantities of a test mixture of a-, B-, y-,... 

The target consists of a printed circuit board with two circuits. One circuit is exposed. The second circuit is protected and is used to compensate for the effect of elevated temperature on the electrical resistance of the circuit. The target is removed from the chamber 1 h after the start of a test and the reduction of the electrical resistance of the exposed circuit is measured. The target is then exposed to an atmosphere of 23°C and relative humidity of 75% for 24 h. The electrical resistance is measured again after the 24 h post-test exposure. The electrical resistance measurements are converted to the equivalent reductions in metal thickness, C, and C2 respectively, expressed in nanometers. 

Schatz and Koopman (1990) reported on the Hawk series, 87 tests conducted at the DOE Nevada test site. These experiments were large-scale chamber releases of HF, as well as laboratory experiments. The objective of these tests was to study the effect of the water-to-HF ratio, water spray geometry, water application via a fire monitor, acid type (anhydrous HF and alkylation unit acid (AUA)), acid temperature and pressure, water additives, relative humidity, wind speed, and steam as an acid jet dispersant on HF removal efficiency. Figure 4.2 shows removal efficiencies ranging from 25 to 90% for water-to-HF volumetric flow ratios ranging from 6 1 to 40 1. Fire monitors provided removal efficiencies comparable to those of water sprays. Some of the conclusions reached by the authors were ... 

The basic mission of the Physics and Biology Laboratories is to test paper treated with products used in the restoration process. Physics is in an air-conditioned room, maintained at 60% relative humidity at 21°C, equipped with machines for testing folding endurance, tensile, and burst strength of paper. Biology runs tests, primarily with culture media, to determine the susceptibility of the treated paper to attack by microorganisms these are identified and a determination is made on how to avoid or eradicate them. Aging chambers are available for tests made by the laboratories. 

A much more recent development is the morpholine process in which fifty books per hour are treated in an evacuated chamber with morpholine-water vapor (12). In its present form, it was effective on 95% of the papers treated, prolonging their life on average by a factor of 4-5 (Figure 7). Though it does not leave a titratable alkaline reserve in the paper, acid papers treated in this manner aged in the presence of 5 ppm S02 at 75 °C and 60% relative humidity deteriorate more slowly than if untreated. Recent tests of twenty treated books at the Library of Congress show that their pH has not declined in two years. The equipment for the process was set up in the Virginia State Library where 35,000 books were treated in the first seven months of operation. 

Table 3 Changes in Chamber Temperature and Relative Humidity During a Photostability Test (Lamp On ) and After (Lamp Oft )...

Herrmann investigated in more detail the influence of water adsorption on the tensile and shear strengths of compacts made from barium sulfate. Figure 78 shows some results. The tensile and shear strengths were determined on compacts produced and stressed in a high vacuum and at various levels of relative humidity of the test chamber atmosphere. Since the normal relative humidity is often in a range between 60 and 80%, all conditions investigated... 

In 1996, investigations on PVC products were performed in test chambers under defined conditions [86]. At room temperature the DEHP concentration was below 0.1 pg m At higher temperatures the chamber values increased as expected. The maximum value was 5.2 pg m (60 °C). Wilke and Jann [87] described test chamber investigations on wallpapers containing DEHP. In tests over 28 days in chambers of 1 m (23 °C, 45% relative humidity, air exchange rate 1 h loading 1 m m ) DEHP was not detectable with a detection limit of 0.35 pg m Only when the temperature was increased to 40 °C were DEHP values of up to approximately 2 pg m measured. 

In the dynamic chamber tests, the large chamber (55.4 m ) was loaded at a rate of 0.43 m /m, and the ventilation rate was maintained at 0.5 air changes per hour. The test temperature was 25 1 C, and the relative humidity was held at 50 + 5%. Air sampling was accomplished with three sets of double impingers at one liter per minute for 60 minutes, twice per day for two days. Formaldehyde was analyzed using the acetylacetone procedure (10). 

Specimens were preconditioned at the same temperature and relative humidity as is given for the test chamber. 

These test chambers can be incorporated to the enzymatic methods for formaldehyde determination. Formaldehyde emissions of a product, or mix of products, to the ambient air can be collected in distilled water or 1% sodium bisulfite as the absorbing solution. After collection, formaldehyde samples are analyzed as described above. In the mobile home simulator test method (2J, double or triple impingers, which are placed in series, should be used in order to collect all of the formaldehyde vapor. The test conditions should simulate the actual environment. Several factors such as temperature and relative humidity of the system including the specimens and background of formaldehyde in the test chamber, affect the precision and accuracy of the results. It has been shown that a 7 C change in temperature doubles the emission level (L). The temperature of the test chamber should be... 

Each of the test chambers has an internal volume of 1.0 m and consists of stainless steel, with the dimension 1 000 x 1 500 X 667 mm. The chambers are supplied with air of constant temperature (23 0.5 C) and constant relative humidity (50 3 %... 

All quality control tests and specimen conditioning are conducted under carefully controlled environmental conditions, i.e. temperature = 24 H3.5 C, 50h 5% relative humidity and a background formaldehyde level of less than 0.1 ppm. Ourselves as well as others have found that temperature effects on the quality control test values follow the same pattern observed in the large scale chamber (30). In short, the Berge temperature correction can be applied to the quality control test methods. 

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