Luminometer number

However, the smoke point is not always a reliable criterion of combustion performance and should be used in conjunction with other properties. Various alternative laboratory test methods have previously been specified such as the lamp burning test (ASTM D-187, IP 10) and a limit on the polynuclear aromatic content (ASTM D-1840), as well as the luminometer number (ASTM D-1740). 

The test for luminometer number (ASTM D-1740) was developed because certain designs of jet engine have the potential for a shortened combustion chamber fife because of high liner temperatures caused by radiant heat from luminous flames.The test apparatus is a smoke point lamp modified to include a photoelectric cell for flame radiation measurement and a thermocouple to measure temperature rise across the flame. The fuel luminometer number (LN) is expressed on an arbitrary scale on which values of 0 to 100 are given to the reference fuels tetralin and iso-octane, respectively. 

Note 1—There is good correlation between Luminometer number (Test Method D 1740) and smoke point which is represented in Appendix XI. 

D 1740 Test Method for Luminometer Number of Aviation Turbine Fuels ... 

The smoke point (and Luminometer number with which it can be correlated) is quantitatively related to the potential radiant heat transfer fi-om the combustion products of the fuel. Because radiant heat transfer exerts a strong influence on the metal temperature of combustor liners and other hot section parts of gas turbines, the smoke point provides a basis for correlation of fuel characteristics with the life of these components. 

XI. 1.1 There is a good correspondence between smoke point (SP) (Test Method D 1322) and luminometer number (LN) (Test Method D 1740). Figure X1.1 shows this relation-... 

XI.1.2 The relationship is based on regression of data on 315 fuels having luminometer numbers falling within the range from -2 to 100. There were 160 Jet A, A-1, JP-4, and JP-S fuels in this group. The remaining fuels were diesel fuels, kerosines, blends of refinery fractions, and other miscellaneous petroleum fractions. 

XI. 1.4 It can be demonstrated that the confidence intervals about the correlation line is explainable almost completely by the inherent error in ffie smoke point and luminometer measurements. This means that if there is a fuel-type effect different for each of the two methods, it is small and masked by smoke point and luminometer number measurement errors. 

XI.2.2 The equations are obviously not mathematical identities but yield results that do not differ by more than 0.1 smoke point or luminometer number points. Both equations are presented to facilitate ease of calculation depending on which variable is given. 

As noted above, the number of integrated instruments has grown tremendously. However, the intrinsic quality of equipment that can be considered as subsystems or components for assembling, for instance, an imaging luminometer has also greatly increased. As a consequence, even today, an expert user may assemble a unit to carry out a specific job with good efficiency. 

In summary, chemiluminescence is a sensitive, non-invasive technique that can measure reactive oxidant production by small numbers of neutrophils indeed, neutrophil-derived chemiluminescence can be detected in as little as 5 fA of unfractionated human blood. The assay is suitable for automation using either multichannel luminometers or luminescence microtitre plate readers. Many researchers, however, have questioned the usefulness of this technique because of the uncertainty of the nature of the oxidant(s) that are detected. Nevertheless, in view of the recent developments made towards the identification of the oxidants measured and the assay s ability to detect intracellular oxidant production, it is has an important place in the phagocyte research laboratory. 

These approaches differ from fluorescence and other luminescent techniques such as phosphofluorescence in that the excitation event is caused by a chemical reaction rather than photolumination. There are a number of reviews that detail the development and applications of luminescent technology (52,53,54,55,56, 57, 58) and instrumentation (59, 60). Particularly outstanding is the recent detailed review by Stanley (61) where more than 90 luminometers (manual, automatic, microtiter plate, HPLC, LC, GLC, imaging, and others) from more than 60 sources are described. 

The first, and simplest of these, exploits the fact that cationically charged microspheres (which can be magnetic particles) selectively bind hybridized AE probes. Thus, after a solution-phase hybridization between a DNA AE probe and a target ribosomal RNA, containing a sequence complementary to the probe, the hybridized probe can be removed in a 10-min separation step and quantitated in a luminometer (Gil, T6). Assays have been described for a number of bacterial... 

There are a number of techniques available to extract ATP from cells. Some use trichloroacetic acid (TCA), which also aids in stabilizing the molecule. TCA has a good extraction capacity, is relatively quick, has a reduced potential for human error, and does not discriminate between the different microbiological fractions of activated sludge. Luminescence produced in the luciferin-luciferase reaction can be measured using scintillation counting equipment or a range of luminometers currently on the market. 

There are a number of ATP systems currently available, including UltraSnap (Hygi-ena), PocketSwab Plus (Charm Sciences), Hy-Lite (VWR) and Clean-Trace (3M). The UltraSnap system contains a premoistened swab in a tube and the reaction reagent in a cap on the top. A certain area of surface is wiped over with the swab. Once the cap is closed the reagent moves down to the swab and the tube is shaken a few times. If there is ATP present on the swab it will react with reagent containing luciferyl adenylate. The result of the positive reaction will be bioluminescence, which can be detected in a luminometer. 

In a luciferase assay a flash of light is generated that decays rapidly after the enzyme and substrates are combined. For this reason, the use of flash kits requires rapid measurement within 5 min upon substrate addition and since a screen requires processing large numbers of plates, a luminometer coupled with an automated plate stacker is also required unless luciferase kits optimized for extended signal duration are used. 

When analyzing the plate for toxicity, verify that three larvae have been placed correctly in each well. Note if more or less animals have been placed so that the luminometer value can be adjusted to the acmal number of larvae per well. Plates that have been manually loaded frequently contain a few wells with the incorrect number of larvae. 

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