Moisture content, test

Fig. 1. Combinations of inoculum amount and moisture content tested.

Combinations of inoculum amounts and moisture contents tested in this exploratory study are shown in Fig. 1 controls lacking inoculum were also conducted at 0.4-0.77 g of H20/g of stems and are not shown in Fig. 1. The first tests performed (4) are represented by the 12 points in the lower left-hand corner of Fig. 1. When these tests indicated that higher inoculum was needed for better selectivity and that higher moisture was needed for faster degradation (4), parameter testing moved to the combinations plotted in the upper middle and right-hand corner of Fig. 1. 

Soil classification particle grain size distribution, hydrometer, Atterberg limits, field identification tests, linear shrinkage and moisture content test ... 

Dielectric strength of oil/chemical composition and moisture content (test certificate for oil should be obtained from a standard laboratory). 

The KDF filter was first tested in prototype on a coal mine in northern Germany. It was installed in parallel with existing vacuum filters and it produced filter cakes consistendy lower in moisture content by 5 to 7% than the vacuum filters. Two production models have been installed and operated on a coal mine in Belgium. The filter is controlled by a specially developed computer system this consists of two computers, one monitoring the function of the filter and all of the detection devices installed, and the other controlling the filtration process. The system allows optimization of the performance, automatic start-up or shut-down, and can be integrated into the control system of the whole coal washing plant. 

The test results reported show the advantages of pressure filtration quite clearly, ie, the dry cake production capacity obtained with the test soHds (coal suspensions) was raised 60 or 70% and the final moisture content of the cake reduced by as much as 5 to 7% by increasing the pressure drop from 60 to 200 kPa. Further increases in the operating pressure bring about less and less return in terms of capacity and moisture content. 

Water Activity. The rates of chemical reactions as well as microbial and en2yme activities related to food deterioration have been linked to the activity of water (qv) in food. Water activity, at any selected temperature, can be measured by determining the equiUbrium relative humidity surrounding the food. This water activity is different from the moisture content of the food as measured by standard moisture tests (4). 

Moisture content affects a number of appHcations. The grindabiUty index, ASTM D409, measures the relative ease of pulverising coals and theoretically helps determine the capacity of pulverizers. In practice, low values of grindabiUty occur at moisture extremes and maximal grindabiUty occurs at intermediate moisture content. A small pulverizer to test grinding conditions for design purposes has been developed (20). 

Other Measurements. Other tests include free moisture content, rate of dissolution and undissolved residue in acids and alkaH, resin and plasticizer absorption, suspension viscosity, and specific surface area. Test procedures for these properties are developed to satisfy appHcation-related specifications. 

These relationships predict the binding Hquid content for wet agglomeration with an accuracy of only ca 30%. The Hquid content required to agglomerate a particular feed material depends, for example, on the interfacial properties of the system (45). Typical values of moisture content required for hailing a variety of materials are listed in Table 2. Very accurate information on the optimum Hquid content to agglomerate a particular feed material must be obtained from experimental tests. 

Higher temperatures result in permanent degradation. The amount of this irreversible loss in mechanical properties depends upon moisture content, heating medium, temperature, exposure period, and, to some extent, species. The effects of these factors on modulus of mpture, modulus of elasticity, and work to maximum load are illustrated in Figures 6—9 (6). The effects may be less severe for commercial lumber than for clear wood heated in air (Fig. 10). The permanent property losses shown are based on tests conducted after specimens were cooled to - 24° C and conditioned to a moisture content of... 

D. W. Green and J. W. Evans, "Moisture Content and the Mechanical Properties of Dimension Lumber Decisions for the Euture" ia D. Green and co-eds.. Proceedings no. 47363, In-Grade Testing of StructuralDumber, Madison, Wise., April 25—26, 1988, Eorest Products Society, Madison, Wise., 1989. 

Testing. The Technical Association of the Pulp and Paper Industry (TAPPl) gives test methods that are widely used by kaolin suppHers to the paper iadustry. These iaclude tests for viscosity, viscosity stabiUty, brightness, pH, particle size distribution, moisture content, and screen residue (12). 

Pretreatment Chemicals Even though the suspended solids concentration of the slurry to be tested may be correct, it is frequently necessary to modify the sluriy in order to provide an acceptable filtration rate, washing rate, or final cake moisture content. The most common treatment, and one which may provide improvement in all three of these categories, is the addition of flocculating agents, either inorganic chemicals or natural or synthetic polymers. The main task at this point is to determine which is the most effective chemical and the quantity of chemical which should be used. 

For materials of moderate to low porosity, a good starting vacuum level is 0.6 to 0.7 bar (18 to 21 in Hg), as the capacity of most vacuum pumps starts to fall off rapidly at vacuum levels higher than 0.67 bar (20 in Hg). Unless there is a critical moisture content which requires the use of higher vacuums, or unless the deposited cake is so impervious that the air rate is extremely low, process economics will favor operation at vacuums below this level. When test work is carried out at an elevation above sea level different than that of the plant, the elevation at the plant should be taken into account when determining the vacuum system capacity for high vacuum levels (>0.5 bar). 

Remaining terms to right of the bracket relate to properties to be measured within the matrix. The factor/is adjusted from 0 to 1 in relationship to the purpose of testing. A low value of/is indicated for scarce elements such as precious metals in electronic-source scrap. Moisture content has a high/value. The factor g is adjusted from 0 to... 

Estimating Minimum Sample Quantity for Moisture Measurement Estimates of material quantity for testing moisture content depend on mechanisms of moisture distribution in the material. Moisture is physically retained on particle surfaces, chemically adsorbed on surfaces and within pores of particulate solids, and contained as an internal constituent of solids. Significant internal moisture is most often encountered in organic and agricultural source materials. 

CFR Part 60 (Appendix A) New source performance standards Methods 1-4 Test location, volumetric flow rate, gas composition, moisture content... 

A d.c. insulation resistance test or polarization index reveals only the surface condition of the insulation and does not allow a realistic assessment of internal condition. Loss tangent values are true reflections of the insulation condition to detect moisture content, voids, cracks or general deterioration. The tan 5 versus test voltage curve may be drawn and compared with the original curve provided by the manufacturer, and inferences drawn regarding the condition of the insulation. The different starting tan lvalues will reveal the condition of the insulation in terms of amount of contamination, as noted in Table 10.4 (See lEE, Vol. 127, May 1980). 

The data presented in Figure 19.7 were obtained on a Sonntag-Universal machine which flexes a beam in tension and compression. Whereas the acetal resin was subjected to stresses at 1800 cycles per minute at 75°F and at 100% RH, the nylons were cycled at only 1200 cycles per minute and had a moisture content of 2.5%. The polyethylene sample was also flexed at 1200 cycles per minute. Whilst the moisture content has not been found to be a significant factor it has been observed that the geometry of the test piece and, in particular, the presence of notches has a profound effect on the fatigue endurance limit. 

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