Limit test

Pesticides Limited Testing Finds Feii> Exported Unregistered Pesticide Violations on ImportedFood GAO/RCED-94-1, U.S. General Accounting Office, Washington, D.C., Oct. 1993, 34 pp. 

If a design limit test is included in the test run (such as a hydrostatic test) and it exceeds safe operating limits, consider writing a special procedure for this part of the test. 

Atterberg-limit tests determine the water content influence in defining liquid, plastic, semisolid and solid states of fine-grained soils. Permeability tests may be carried out in the laboratory or in the field. Such tests are used to determine the hydraulic conductivity coefficient k. ... 

In the early 1960s efforts were made in the United States to operate vane motors and reciprocating motors with compressed air. The vane motors experienced some limited test success but were not competitive in the market of that day [84]. Out of these development efforts evolved the reciprocating (compressed) air hammers that have been quite successful and are operated extensively in the mining industry and have some limited application in the oil and gas industry [85]. The air hammer is not a motor in the true sense of rotating equipment. The reciprocating action of the air hammer provides a percussion effect on the drill bit, the rotation of the bit to new rock face location is carried out by the conventional rotation of the drill string. 

United States Pharmacopeia (1995) 23rd revision. Rockville, MD US Pharmacopeial Convention. (Note the section dealing with microbial limit tests.)... 

When the test for related substances is a limit test, the peaks of the impurities in the chromatogram of the test solution can be compared to the peak of the test substance in the chromatogram of a dilution of the test solution at the limiting concentration. The approach is vahd provided that the response factors of the impurities and the test substance are equivalent using the detector conditions described, otherwise correction factors need to be applied. 

Substances (impurities) which are not the subject of a monograph are usually synthesized or supplied by the manufacturer. In this case a purity in excess of 90.0 % is required provided that the reference substance is employed in a limit test. If the reference substance (impurity) is employed in a quantitative test then the purity requirement is normally better than 99.0 %. When it is less, then an assigned content must be established. 

Microbiological aspects will need to be discussed, but the amount of information will depend on the type of product. For nonsterile products there will need to be a description of the microbiological attributes of the product and, if appropriate, a rationale for not performing microbial limit tests. For preserved products the selection of the antimicrobial preservatives will need to be discussed and the effectiveness of the selected system demonstrated. For sterile products there will need to be appropriate process validation data and information on the integrity of the container-closure system. 

Suppose that a company has been using a certain supplier of raw materials in one of its chemical processes. A new supplier approaches the company and states that its material, at the same cost, will increase the process yield. If the new supplier has a good reputation, the company might be willing to run a limited test. On the basis of the test results it would then make a decision to change suppliers or not. Good management would dictate that an improvement must be demonstrated... 

To 2 g of niclosamide add a mixture of 1.2 mL of acetic acid and 40 mL water, boil for 2 min, cool and filter. Two milliliters of the filtrate diluted to 15 mL with water complies with the limit test for chlorides (500 ppm) [6]. 

According to BP 2003 [4], European Pharmacopoeia [2], a 0.5 g of test substance complies with limit test C (50 ppm). The standard is prepared using 2.5 mL of lead standard solution (10 ppm Pb). 

The most common types of analyses are the identification test, the quantitative determination of active ingredients or major component, and the determination of impurities. The identification test provides data on the identity of the compound or compounds present in a sample. A negative result signifies that the concentration of the compound(s) in sample is below the DL of the analyte(s). The quantitative method for the major component provides data of the exact quantity of the major component (or active ingredients) in the sample, and a reported concentration of the major component must be higher than the QL. In a Determination of impurities test, one obtains data regarding the impurity profile of a sample, and can be divided into a limit test or quantitative reporting of impurities (see Table 1, which has been modified from Refs. [1] and [8]). 

Type of analytical procedure Assay Impurity testing Quantitative Limit tests Performance characteristics Identification ... 

Preliminary research has shown that Brillouin fiber-optic sensing systems provide a possible method to detect leaks and third-party intrusion on a pipeline over distances of 25 km or more. Their intrinsic response to both temperature and mechanical strain allows for the separation of these parameters and the detection of anomalies in the scan profiles. In addition, the same sensor could be integrated into the pipeline system to detect possible ground movement relative to fixed reference points. Limited test results on surface loads associated with the intrusion of vehicles and people on a pipeline have demonstrated the sensitivity of the system and its ability to discriminate loads at different soil depths. 

No studies have been conducted with silver and avian or mammalian wildlife, and it is unreasonable to extrapolate the results of limited testing with domestic poultry and livestock to wildlife to establish criteria or administratively enforced standards. Research on silver and avian and terrestrial wildlife merits the highest priority in this subject area. No silver criteria are available for the protection of avian and mammalian health, and all criteria now proposed are predicated on human health (Table 7.8). As judged by the results of controlled studies with poultry and small laboratory mammals, safe concentrations of silver ion were less than 250 pg/L in drinking water of mammals, less than 100 mg/L in drinking water of poultry, less than 6 mg/kg in diets of mammals, less than 10 mg/kg in copper-deficient diets of poultry, less than 200 mg/kg in copper-adequate diets of poultry, and less than 1.8 mg/kg in chicken eggs. The proposed short-term (10-day) allowable limit of 1142 pg Ag/L in drinking water for human health protection (Table 7.8) should... 

Bifenthrin Aphidius rhopalosiphi Limit test Mortality 7.5 g a.i./ha - 100%... 

Esfenvalerate cacoeciae Typhlodromus pyri Limit test Mortality/ 15 g a.i./h - 10%... 

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