Novel methodology for turbine gas meters error curve modelling across a wide range of operating parameters

In this paper, performance of turbine flowmeters was investigated for different flowmeter ranges and working gas operating pressures. Variation of these parameters was represented in dimensionless form as a function of Reynolds Number and gas density ratio, while the relative flow measurement error was selected as the most important operating characteristic. A novel error curve model based on turbine machine theory and dimensionless analysis was introduced for the purpose of error data fitting across a wide range of gas flow rates and operating pressures. The main advantage of the presented model is the capability of accurate error data fitting with a single continuous equation, as demonstrated by high R 2 {R^{2}} values for the vast majority of flowmeters analyzed in this study. The acceptability criterion was designed based on the fact that the expanded measurement uncertainty of the relative error must not exceed 0.5 %. Besides an accurate interpolation, our model can also be utilized for prediction of turbine flowmeter performance at modified flow conditions (pressure and flow rate, working gas properties), and for assessment of the drift of flowmeter performance over time. The novel error curve model is demonstrated to outperform the standard polynomial-based model regardless of the independent variable used.

Vendor-Recommended Protocol Is Not Adequate To Verify Analyzer Performance After Probe Replacement

Introduction/Objective To verify performance after probe replacement on Siemens ADVIA® 1800 analyzer, the vendor recommends running 2 levels of quality control (QC) for each analyte; however, this approach provides only a snapshot of analyzer performance. Additional experiments were conducted to determine if the vendor-recommended protocol adequately verifies analyzer performance. Methods Serum from 20 random patients was mixed, centrifuged at 1000 g for 10 min, and supernatant prepared (PPS). Intra-assay precision was assessed by analyzing 20 replicates of 2 levels of QC, and PPS for the following indicator assays (total allowable error [TEa] in parentheses): alanine aminotransferase (20%), calcium (6%), creatinine (15%), immunoglobulin G (25%), and sodium (5 mEq/L). Inter-assay precision over past 30 days was calculated from the values (90 – 114) of 2 levels of QC. Violation of 13s QC rule is most commonly used for detecting critical error (error > TEa). We used TEa/4 and TEa/3 as the acceptability criteria for intra- and inter-assay precision. Inter-assay precision was also compared to the precision claim by the vendor. Bias between the mean of QC values from intra- and inter- assay precision was calculated and TEa/4 used as the acceptability criterion. Results Intra-assay precision for both levels of QC for all analytes was acceptable. Intra-assay precision (5.48%) for only alanine aminotransferase in the PPS was unacceptable, indicating that patient matrix may impact precision for certain analytes. Inter-assay precision (2.24%) for level 1 QC for calcium was unacceptable. For all analytes, inter- assay precision compared to vendor’s claim was found to be significantly higher (32% - 405%). The bias was unacceptable for level 3 QC for sodium (-2.11). Conclusion Increased imprecision and/or bias may be observed if either probe replacement or alignment was not appropriate; or the verification protocol was not adequate. This study demonstrates the need to conduct experiments beyond vendor-recommended protocol to ensure production of clinically acceptable results.

Trudy Govier and Premise Adequacy

My main concern in this paper is with Trudy Govier’s acceptability criterion for the adequacy of the premises of an argument considered independently of whether they are “properly connected” to the conclusion. I consider arguments she makes against the view that a good argument must have true premises, and I con-tend that a theory of argument could hold both that for an argument to be a good argument its premises must be true and that for it to be a good argument relative to its audience, the audience must be epistemically justified in accepting its premises as true.

Global Convergence of a New Nonmonotone Filter Method for Equality Constrained Optimization

A new nonmonotone filter trust region method is introduced for solving optimization problems with equality constraints. This method directly uses the dominated area of the filter as an acceptability criterion for trial points and allows the dominated area decreasing nonmonotonically. Compared with the filter-type method, our method has more flexible criteria and can avoid Maratos effect in a certain degree. Under reasonable assumptions, we prove that the given algorithm is globally convergent to a first order stationary point for all possible choices of the starting point. Numerical tests are presented to show the effectiveness of the proposed algorithm.

A New Method to Analyze Seismic Stability of Cut Soil Slope

A new method to analyze the seismic stability of the cut soil slope is suggested in this study. In the method, the limiting equilibrium theory and the stress analyzing method are used. The stress acceptability criterion is based on the limited strength of soil. Two basic assumptions are given in the method. One is that the slip surface can be replaced by a series of straight lines. The other is that the interslice boundary is an inclined plane. Three balance equations for any slice, which are two for force equilibrium and one for moment equilibrium, are proposed. An iterative method, which solves the balance equations from the first slice to the last slice, is also suggested. In the new method, the slip surface is not predefined, but is obtained slice by slice going from downhill to uphill in terms of the force and moment balance equations of the slice.

RBMK Safety Analysis in Accidents Initiated by Partial Ruptures of the Circulation Circuit

The paper gives an analysis of the current state of the RBMK safety evaluation in accidents initiated by partial ruptures of the delivery part of the circulating loop. It appears from this analysis that applicability and uncertainty of the international code RELAP for RBMK safety analysis could not be determined up to the present. At the same time it is shown in the paper that fuel rod cladding temperature can reach the acceptability criterion in the accidents. As a result it has been concluded that bases of the next stage of the RBMK safety analysis would be creation of a code oriented to the special features of a reactor RBMK.

EVALUATION OF THREE OIL SPILL LABORATORY DISPERSANT EFFECTIVENESS TESTS

ABSTRACT Chemical dispersants can be used to reduce the interfacial tension of floating oil slicks so that the oils disperse more rapidly into the water column and thus pose less of a threat to shorelines, birds, and marine mammals. The laboratory test currently specified in federal regulations to measure dispersant effectiveness is not especially easy or inexpensive, and generates a rather large quantity of oily waste water. This paper describes the results of an effort by the U.S. Environmental Protection Agency (EPA) to identify a more suitable laboratory dispersant effectiveness test. EPA evaluated three laboratory methods: the Revised Standard Dispersant Effectiveness Test currently used (and required by regulation) in the United States, the swirling flask test (developed by Environment Canada), and the IFP-dilution test (used in France and other European countries). Six test oils and three dispersants were evaluated; dispersants were applied to the oil at an average 1:10 ratio (dispersant to oil) for each of the three laboratory methods. Screening efforts were used to focus on the most appropriate oil/dispersant combination for detailed study. A screening criterion was established that required a combination that gave at least 20 percent effectiveness results. The selected combination turned out to be Prudhoe Bay crude oil (an EPA-American Petroleum Institute Standard Reference Oil) and the dispersant Corexit 9527. This combination was also most likely to be encountered in U. S. coastal waters. The EPA evaluation concluded that the three tests gave similar precision results, but that the swirling flask test was fastest, cheapest, simplest, and required least operator skill. Further, EPA is considering conducting the dispersant effectiveness test itself, rather than having data submitted by a dispersant manufacturer, and establishing an acceptability criterion (45 percent efficiency) which would have to be met before a dispersant could be placed on the Product Schedule of the National Contingency Plan (NCP). Also under consideration by EPA is a sequential testing procedure for a dispersant being placed on the schedule, whereby successful effectiveness testing would be required before toxicity testing would begin.