Workability tests

The Joint Panel proposed no in vivo requirements, but individual dissolution testing requirements were adopted in 12 compendial monographs. USP tests measured the time to attain a specified amount dissolved, whereas NF used the more workable test for the amount dissolved at a specified time. Controversy with respect to equipment selection and methodology raged at the time of the first official dissolution tests. As more laboratories entered the field, and experience (and mistakes ) accumulated, the period 1970-1980 was one of intensive refinement of official test methods and dissolution test equipment. 

The quality of building limes is specified in [22.6]. It requires minimum values for standard mortars produced from lime putties — namely penetration and air content — and lists water demand and water retention as parameters that customers may request. It also specifies a minimum volume yield of putty per kg of quicklime. Building limes must also be sound (i.e., pass the popping, pitting and expansion tests). A workability test, based on the spread of a standard mortar on a jolting table, was specified in the 1972 edition of BS 890 [22.11], but is no longer included. 

Sand Rammer. The standard rammer for making test-pieces allows a 14 lb (6.25 kg) weight to fall 50 mm on sand contained in a 50 mm diam. mould three blows from the rammer are used in making a standard test-piece. Its use in compaction and workability tests for unshaped refractories is specified in B.S. 1902 Pt. 7.2. 

A New Filter Test. Because tests using cores are relatively expensive and time consuming, we developed a filter test using filters that mimicked the plugging behavior seen during the core tests. After some experimentation, we identified a workable test using a Millipore APIO filter pad upstream of a 10 pm polycarbonate (Sterlitech Track Etch ) membrane filter (both 13 mm in diameter). Fig. 5 compares filtration results for X US K K36 xanthan (solid circles) with results from the core test (solid triangles). The... 

Fibres generally tend to stiffen a concrete mix, and make it seem harsh when static, though it may still respond well to vibration. Under vibration, the stiffening effect of the fibres tends to disappear, and so a properly designed FRC mix can be handled in much the same way as plain concrete in terms of mobility and ability to flow [1]. Therefore, workability tests based on static conditions, such as the slump test, are not very useful, and can be quite misleading, since the concrete is in fact workable when vibrated. Thus, in order to assess the workability of fresh FRC mixes, it is recommended that tests in which dynamic effects are involved be used [1,2]. 

Over the years, a great many workability tests have been devised. Koehler and Fowler [3] have described 61 different test methods, though only some of these have ever been adopted as standards, and even fewer are used for FRC. The most common test methods in current use include ... 

Figure 6.2 Relations between the results obtained by various workability tests of fibre reinforced cements, (a) Slump vs. VeBe (b) VeBe vs. inverted slump cone (after Johnston [I]).

It should be noted that all workability tests mentioned above (and indeed almost all others) merely provide a comparative assessment of different FRC mixes they do not measure parameters of physical significance. 

Workability tests for the mortar matrix in sprayed fibre reinforced cement are specified mostly for glass fibre reinforced cements. They are based on the spread of a slurry which is cast into a cylindrical mould, with the mould subsequently lifted to allow the slurry to spread. 

Figure 2.3.1 (Wachtel, et al, 1972) shows the ARCO reactor that tried to simulate the real reaction conditions in a fluid cracking unit. This was a formal scale-down where many important similarities had to be sacrificed to get a workable unit. This unit was still too large for a laboratory study or test unit, but instead was pilot-plant equipment that could still give useful empirical results Since this serves a very large industry, it may pay off to try it, even if it costs a lot to operate.

Originally the classification of materials was derived from tests of proprietary explosion-proof (flameproof) enclosures. There were no published criteria. Equipment was approved relative to the lowest ignition temperature of any material in the group (Magison 1987). In about 1965 the U.S. Coast Guard asked the National Academy of Sciences (NAS) to form a panel to classify 200 materials of commerce. The Electrical Hazards Panel of the Committee on Hazardous Materials was formed by the NAS. The Panel studied many ways to estimate the hazard classification of materials. The Panel finally reported to die U.S. Coast Guard in 1970 that no workable, predicdve scheme could be defined, and it then proceeded to assign tentative classifications to the 200 materials. 

As part of planning your company s PSM system roll-out (Chapter 7), you have established a number of benchmarks and parameters for the installation process. For example, pilot testing should yield realistic estimates for individual facilities schedule, staffing, and other resource requirements, as well as workable formats for reporting. The installation plan you developed should derive from these results, adapting them to the full range of your company s operations. 

Being 26 months into the program for the later batch (53 months for the earlier one), the method was checked and found to be moderately tricky, but workable. Technician B (bold circles) did the final tests on both batches. When the... 

Consistency, working time, setting time and hardening of an AB cement can be assessed only imperfectly in the laboratory. These properties are important to the clinician but are very difficult to define in terms of laboratory tests. The consistency or workability of a cement paste relates to internal forces of cohesion, represented by the yield stress, rather than to viscosity, since cements behave as plastic bodies and not as Newtonian liquids. The optimum stiffness or consistency required of a cement paste depends upon its application. 

The phase diagram of some oil-solubilizer-water must be measured as a function of temperature in order to test the above approach. For this purpose decane (DEC) was chosen as a typical oil and 2-bu-toxyethanol (BE) as the solubilizer. We thought BE would be a good model solubilizer since the lower critical solution temperature for the BE-H2O system is 49 C this gives a good workable temperature range for our investigation. 

I heard from Dr. Grow that dog urine (of all things) can be substituted, and will pass the test However, I don t know how an age, gender, pH, or creatinine test would result. Someone was able to use dog urine for several months to pass the test. This subsection assumes you have a clean dog. I know my dog s urine wouldn t pass he eats more weed than humans do. It would make more sense to use human urine, but dog urine provides a workable substitution in an emergency. 

The initial plastic state of the fresh concrete subsequent to the mixing process, where properties such as the air content, density and workability are normally measured by relevant standard tests, and utilized as a means of control of production. The magnitude of these properties is affected by the addition of water-reducing admixtures, either intentionally or as a side effect, which could result not only in a change in the characteristics in the plastic state, but could also be reflected in changed properties in the hardened state. 

The initial plastic state of the fresh concrete when properties such as the workability as measured by slump or flow table test or air content can be determined by the relevant standard method. 

In the engineering development stage, a practical and workable design is developed. Prototype samples are produced on equipment located at the Technical Center that duplicates the production process to be used. A portion of the materials evaluation work is also performed at this time. Candidate materials are given performance tests and moldability is analyzed in detail. Cost and reliability factors are also considered at this time. 

To provide a common basis for discussion, we have attempted in this chapter to provide a workable, rudimentary model which includes the more important identifiable parameters of anisotropic media responsible for directing photochemical processes. In spite of the many examples cited during its development and the many more which have not been, it is clear that the model requires a great deal more experimental testing and refinement if it is to become a paradigm. We hope that the model will be tested, criticized, and refined in the future. The words of Chalmers [69], that a paradigm will always be sufficiently imprecise and open-ended to leave plenty of work to be done, have not been forgotten. 

Retorting of the total oil sand to produce cracked products was tested extensively, and other than the high heat loss to the sand, it appeared to be a very workable scheme. A combination scheme involving hot water washing to produce a wet bituminous froth followed by fluid coking of this froth was the basic operation recommended in the Blair report in 1950 (4). 

The ease with which concrete can be deformed by an applied stress is known as the workability of the concrete and is measured by standard tests such as compacting factor, VeBe or slump under arbitrarily chosen conditions of sample... 

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