Test Acceptance Criteria Research Articles

A prediction interval approach to developing life test acceptance criteria for progressively censored data

In this paper we use the prediction-interval approach to construct acceptance criteria to determine whether or not certain batches of products are acceptable. The procedure is intended to protect both producers and consumers against highly defective lots and demonstrate that a required quality level is met with certain probability. The prediction interval approach is particularly useful to employ when the lifetime of the product represents the quality characteristic of interest. On the basis of a progressively censored sample from the Weibull lifetime distribution, the problem of constructing acceptance criteria by predicting a future lifetime based on an independent past sample of lifetimes from the same distribution is addressed in a Bayesian setting with a dependent bivariate prior. The Metropolis-within-Gibbs Sampler algorithm is used to obtain a sequence of draws from the posterior predictive distribution of future observations. This sequence is used to derive the prediction intervals based on which the lot acceptance criteria are determined. An example using real data is illustrated.

A prediction interval approach to developing life test acceptance criteria for progressively censored data

A prediction interval approach to developing life test acceptance criteria for progressively censored data

Using an interlaboratory study to revise methods for conducting 10-d to 42-d water or sediment toxicity tests with Hyalella azteca.

Studies have been conducted to refine US Environmental Protection Agency, ASTM International, and Environment Canada standard methods for conducting 42-d reproduction tests with Hyalella azteca in water or in sediment. Modifications to the H. azteca method include better-defined ionic composition requirements for exposure water (i.e., >15 mg/L of chloride and >0.02 mg/L of bromide) and improved survival, growth, and reproduction with alternate diets provided as increased rations over time in water-only or whole-sediment toxicity tests. A total of 24 laboratories volunteered to participate in the present interlaboratory study evaluating the performance of H. azteca in 42-d studies in control sand or control sediment using the refined methods. Improved growth and reproduction of H. azteca was observed with 2 alternate diets of 1) ramped diatoms (Thalassiosira weissflogii) + ramped Tetramin or 2) yeast-cerophyll-trout chow (YCT) + ramped Tetramin, especially when compared with results from the traditional diet of 1.8 mg YCT/d. Laboratories were able to meet proposed test acceptability criteria and in most cases had lower variation in growth or reproduction compared with previous interlaboratory studies using the traditional YCT diet. Laboratory success in conducting 42-d H. azteca exposures benefited from adherence to several key requirements of the detailed testing, culturing, and handling methods. Results from the present interlaboratory study are being used to help revise standard methods for conducting 10-d to 42-d water or sediment toxicity exposures with H. azteca. Environ Toxicol Chem 2016;35:2439-2447. © 2016 SETAC.

Effect of diet quality on chronic toxicity of aqueous lead to the amphipod Hyalella azteca.

The authors investigated the chronic toxicity of aqueous Pb to the amphipod Hyalella azteca (Hyalella) in 42-d tests using 2 different diets: 1) the yeast + cereal leaf + trout pellet (YCT) diet, fed at the uniform low ration used in standard methods for sediment toxicity tests; and 2) a new diet of diatoms + TetraMin flakes (DT), fed at increasing rations over time, that has been optimized for use in Hyalella water-only tests. Test endpoints included survival, weight, biomass, fecundity, and total young. Lethal effects of Pb were similar for the DT and YCT tests (20% lethal concentration [LC20] = 13 μg/L and 15 μg/L, respectively, as filterable Pb). In contrast, weight and fecundity endpoints were not significantly affected in the DT test at Pb concentrations up to 63 µg/L, but these endpoints were significantly reduced by Pb in the YCT test-and in a 2005 test in the same laboratory with a diet of conditioned Rabbit Chow (RC-2005). The fecundity and total young endpoints from the YCT and RC-2005 tests were considered unreliable because fecundity in controls did not meet test acceptability criteria, but both of these tests still produced lower Pb effect concentrations (for weight or biomass) than the test with the DT diet. The lowest biotic ligand model-normalized effect concentrations for the 3 tests ranged from 3.7 μg/L (weight 20% effect concentration [EC20] for the RC-2005 test) to 8.2 μg/L (total young EC20 for the DT test), values that would rank Hyalella as the second or third most sensitive of 13 genera in a species sensitivity distribution for chronic Pb toxicity. These results demonstrate that toxicity tests with Hyalella fed optimal diets can meet more stringent test acceptability criteria for control performance, but suggest that results of these tests may underestimate sublethal toxic effects of Pb to Hyalella under suboptimal feeding regimes. Environ Toxicol Chem 2016;35:1825-1834. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and as such, is in the public domain in the United States of America.

Prevalidation of the ex-vivo model PCLS for prediction of respiratory toxicity

In acute inhalation toxicity studies, animals inhale substances at given concentrations. Without additional information, however, appropriate starting concentrations for in-vivo inhalation studies are difficult to estimate. The goal of this project was the prevalidation of precision-cut lung slices (PCLS) as an ex-vivo alternative to reduce the number of animals used in inhalation toxicity studies. According to internationally agreed principles for Prevalidation Studies, the project was conducted in three independent laboratories. The German BfR provided consultancy in validation principles and independent support with biostatistics.In all laboratories, rat PCLS were prepared and exposed to 5 concentrations of 20 industrial chemicals under submerged culture conditions for 1h. After 23h post-incubation, toxicity was assessed by measurement of released lactate dehydrogenase and mitochondrial activity. In addition, protein content and pro-inflammatory cytokine IL-1α were measured. For all endpoints IC50 values were calculated if feasible. For each endpoint test acceptance criteria were established.This report provides the final results for all 20 chemicals. More than 900 concentration–response curves were analyzed. Log10[IC50 (μM)], obtained for all assay endpoints, showed best intra- and inter-laboratory consistency for the data obtained by WST-1 and BCA assays. While WST-1 and LDH indicated toxic effects for the majority of substances, only some of the substances induced an increase in extracellular IL-1α. Two prediction models (two-group classification model, prediction of LC50 by IC50) were developed and showed promising results.

Engineering Properties of Asphalt Concrete Patching Mixtures

Abstract Potholes are a visible and annoying form of pavement distress for highway users. One reason for the short life of pothole repairs is that the commonly used patching mixtures cannot withstand the wet weather and the traffic loading. A comprehensive laboratory investigation was performed to evaluate the engineering properties of hot-mix, cold-laid (HMCL) asphalt concrete patching mixtures. The performance characteristics of patching materials was categorized based on four aspects related to initial stability, in-service durability, water resistance, and workability. The engineering properties of HMCL patching mixes were investigated, including Marshall stability, indirect tensile strength, rutting resistance, pothole simulation, and uniaxial compression. Four binders, one aggregate type, two gradations, and one residual binder content were selected for testing in the laboratory. Test results indicated that curing time, nominal maximum aggregate size, temperature condition, and binder type influenced the performance of maintenance materials. The difference in indirect tensile strength among patching mixtures was shown to be high, and the indirect tensile test appeared to be effective in differentiating patching mixtures. A preliminary criterion of the dynamic stability value of more than 1000 cycles/mm was suggested for maintenance materials for rutting resistance. Patching mixtures subjected to loading cycles of 30 or higher to reach 3-mm rut depth under wet conditions in the pothole test were deemed satisfactory in resistance to moisture-induced damage. The patching mixtures tested exhibited good workability at temperatures of 20°C or higher. Test procedures and acceptance criteria developed in this study could be useful as part of a specification to promote quality of bituminous patching mixtures.

Evaluation of WET Testing as an Indicator of Aquatic Health

This project evaluated the quality of data needed to determine relationships between chronic Whole Effluent Toxicity (WET) test results and instream biological condition. A data quality objectives approach was used, which included several proposed measurement quality objectives (MQOs) that specified desired precision, bias, and sensitivity of methods used. Six facilities (four eastern and two western U.S.) participated in this study, all having design effluent concentrations > 60% of the stream flow. In accordance with a Quality Assurance Project Plan most of the facilities completed four quarters of chronic Ceriodaphnia dubia, and Pimephales promelas (fathead minnow) WET tests, and three quarters of Selenastrum capricornutum (green algae) WET testing following the most recent USEPA methods. Several other WET tests were conducted to address MQOs including splits, duplicates, and blind positive and negative controls. Macroinvertebrate, fish, and periphyton bioassessments were conducted at multiple locations up and downstream of each facility following the most recent USEPA Office of Water bioassessment protocols. Test acceptance criteria were met for most WET tests, however, this study demonstrated the need to incorporate other MQOs in a full study (such as minimum and maximum percent significant differences and performance on blind samples) to ensure accurate interpretation of effluent toxicity. More false positives, lower test endpoint (i.e., higher toxicity), and more “failed” (non-compliant) tests were observed using No Observed Effect Concentrations (NOEC) as compared to IC25s (concentration causing = 25% decrease in organism response compared to controls). Algae tests often yielded the most effluent toxicity in this study, however, this test was most susceptible to false positives and high inter-laboratory variability. WET test results exhibited few relationships with bioassessment results, even when incorporating actual effluent dilution. Neither frequency of WET non-compliance nor magnitude of WET were clearly related to differences in biological condition up and downstream of a discharge for the most part. Macroinvertebrate assessments were most able to discriminate small changes downstream of the effluent, followed by periphyton and then fish. The sampling methods used were robust but a full study should collect more field replicates up and downstream of each discharge to increase detection power. Macroinvertebrate and periphyton assessments together appeared to be sufficient to address project objectives. Fish assessments could be useful as well but would entail more effort and cost per site than expended in this project to be useful. This title belongs to WERF Research Report Series ISBN: 9781843397687 (Print) ISBN: 9781780403793 (eBook)

Statistical Considerations in Setting Product Specifications

According to ICH Q6A (1999), a specification is defined as a list of tests, references to analytical procedures, and appropriate acceptance criteria, which are numerical limits, ranges, or other criteria for the tests described. For drug products, specifications usually consist of test methods and acceptance criteria for assay, impurities, pH, dissolution, moisture, and microbial limits, depending on the dosage forms. They are usually proposed by the manufacturers and subject to the regulatory approval for use. When the acceptance criteria in product specifications cannot be pre-defined based on prior knowledge, the conventional approach is to use data from a limited number of clinical batches during the clinical development phases. Often in time, such acceptance criterion is set as an interval bounded by the sample mean plus and minus two to four standard deviations. This interval may be revised with the accumulated data collected from released batches after drug approval. In this article, we describe and discuss the statistical issues of commonly used approaches in setting or revising specifications (usually tighten the limits), including reference interval, (Min, Max) method, tolerance interval, and confidence limit of percentiles. We also compare their performance in terms of the interval width and the intended coverage. Based on our study results and review experiences, we make some recommendations on how to select the appropriate statistical methods in setting product specifications to better ensure the product quality.

Combined effects of the cyanobacterial toxin microcystin-LR and environmental factors on life-history traits of indigenous cladoceran Moina macrocopa.

Environmental factors are important in that they might interact with toxicants and could affect the concentration-response relationship of the toxicants in the water environment. Microcystins (MCs) produced by algal blooming are natural toxins that exert severe impacts on aquatic organisms. Despite the possibility of interaction effects between environmental factors and MCs, very few studies have been carried out to date. In the present study, the authors evaluated the effect of 3 environmental factors on chronic toxicity of MC-leucine-arginine (MC-LR; 0 µg/L, 0.8 µg/L, 4 µg/L, 20 µg/L, 100 µg/L, 500 µg/L) to the freshwater invertebrate Moina macrocopa. Three environmental factors were determined to reflect the reasonable worst conditions of the water body in South Korea: high water temperature (25 °C), the highest concentration of nutrients (ammonia-nitrogen [NH3 -N] = 3.8 mg/L; nitrate-nitrogen [NO3 -N] = 8.5 mg/L) during the occurrence of algal bloom, and 2 pH conditions of 7.0 and 9.0, which satisfy the test acceptance criteria for the Daphnia test. Among the various environmental factors being tested, high water temperature and NO3 -N elevated chronic toxicity of MC-LR, whereas NH3 -N reduced toxicity. Water pH did not influence chronic toxicity of MC-LR to M. macrocopa. This observation suggests that those environmental factors are responsible for changing the trend of MC-LR toxicity.

Transient Fault Current Test for ITER DC Reactor on DC Test Platform in ASIPP

Transient fault current test of ITER DC reactor is performed to verify the fault suppression capability of DC reactor. In this paper, the research background, test scheme and test platform of transient fault current test of ITER DC reactor are presented in the first place. The next, the test requirements and acceptance criteria are presented. Finally, the calculation and simulation for DC test platform of ASIPP are presented, and the effectiveness of test scheme is proved by the simulation result and the test results based on DC test platform. The contents presented in this paper can be available for short-circuit test of DC reactor with large current.

OP-003 - A review of commercial MEA testing and plea for informative MEA certificates of analysis

OP-002 – Table 1. Post warming re-expansion time, hatching and cell survival rates Treatment group Total number Mean time to Survival rate Hatching by Hatched by Total number of Mean total cell Mean cell survival of embryos re-expand (h) ± SEM (%) 16 h (%) 24 h (%) embryos stained number ± SEM (%) ± SEM CONTROL short 35 1.2±0.33 94.3 55.9 13.8 17 65±3.8 97.0±0.8 LAC short 32 5.8±0.52 90.6 90.6 57.1 12 53±5.2 96.4±1.9 MAC short 33 4.0±0.60 100.0 51.5 17.2 23 71±4.4 92.8±3.7 CONTROL long 33 2.9±0.60 100.0 42.4 15.2 15 65±6.4 90.7±4.4 LAC long 35 7.6±0.60 97.1 91.4 31.4 8 72±9.5 94.2±1.4 MAC long 31 5.6±0.71 100.0 45.2 12.9 24 72±4.0 95.9±1.0 Significant differences for expansion and hatching rates are indicated in Figures 2 and 3. OP-003 A review of commercial MEA testing and plea for informative MEA certificates of analysis Ronny Janssens1, Greta Verheyen1, Rita Cortvrindt2 1Centre for Reproductive Medicine, UZ Brussel, Brussel, Belgium; 2EggCentris BVBA, Anderlecht, Belgium Introduction: ASRM or ESHRE guidelines require that material in contact with gametes or embryos should be non-toxic and tested with an appropriate bioassay. In IVF centres, in-house MEA testing of every lot of disposables or culture medium is not realistic. Laboratories depend on manufacturers and should be able to understand how their MEA tests are performed. Variables necessary to understand a certificate of analysis (COA) and statement “MEA tested” are detailed information on exposureand test protocols. Unfortunately, information on COAs is limited to “MEA tested” and acceptance criteria. Detailed exposure protocol or testconditions are never provided. In 2013, we mailed our suppliers or manufacturers and requested information on their MEA testprotocols and original COA’s of the MEA tests performed. Results: 24 COA’s from 11 different companies were received. MEA testprotocol was either not specified (n=4), a one cell assay (n=17) or a two cell assay (n=1). Limited info on exposure (n=4) and test conditions was disclosed (n=7). Different assay end-points and acceptance criteria were used: percentage blastocyst development on day 5 (n=12), day 6 (n=3) or without specification of the day of evaluation (n=6). On 3 COAs, no endpoint was given. Acceptance criteria were >80% (n=15), >75% (n=5), >70% (n=2) or not specified (n=2). Conclusions: Current commercial MEA testing is not transparant and company’s statement “MEA tested” of limited value. IVF laboratories should challenge suppliers and insist on certified testlaboratories, sensitive, standardized and disclosed MEA test conditions, exposure protocols and acceptance criteria and should select suppliers based on this.

Model of Parameters Controlling Resistance of Pipeline Steels to Hydrogen-Induced Cracking

NACE MR0175/ISO 15156-2 standard provides test conditions and acceptance criteria to evaluate the resistance of carbon and low-alloy steels to hydrogen-induced cracking (HIC). The second option pro...

Quality Considerations in the Establishment of Specifications for Pharmaceuticals

The quality of a commercial pharmaceutical product is set by a well-designed, understood, and executed manufacturing process using high-quality raw materials. In addition, this built-in quality is verified at release and its stability is assured by random sampling and testing of critical product characteristics against established specifications. There are several approaches to how this verification testing is designed, depending on the underlying quality philosophy employed. This article explores different common approaches and briefly discusses the pros and cons of each. In the most general sense, quality can be defined as the extent to which a product meets customer expectation. The common practice in the pharmaceutical industry is to specify test acceptance criteria without clearly defining or relating these criteria to an underlying quality statement about the product. Fundamental to constructing such a quality statement is an assumed definition of what is meant by drug product in this context, that is, batch, individual dosage units, or some other basic unit. As a result, it is not always fully clear what a reasonable customer expectation is. In contrast to current practices, we propose that a transparent quality statement should be formulated for every pharmaceutical product and that the test(s) to verify that the required performance (as defined by the quality statement) should be designed using established statistical techniques.

An overview of research activities on cementitious materials for radioactive waste management

ABSTRACTAn overview is given on research activities on cementitious materials for radioactive waste management systems based on the IAEA Coordinated Research Project (CRP) held in 2007-2010. It has been joined by 26 research organizations from 22 countries which shared their research and practical activities on use of cementitious materials for various barrier purposes. The CRP has initially formulated the research topics considered within four specific streams: A) Conventional cementitious systems; B) Novel cementitious materials and technologies; C) Testing and waste acceptance criteria; and D) Modelling long term behaviour.The CRP has analysed both barrier functions and interactions envisaged between various components with focus on predisposal stage of waste management. Cementation processes have achieved a high degree of acceptance and many processes are now regarded as technically mature. A large body of information is currently available on proven waste conditioning technologies although novel approaches are continuing to be devised.Most of the existing technologies have been developed for conditioning of large amounts of operational radioactive waste from nuclear power plants and other nuclear fuel cycle facilities. However new waste streams including those resulting from legacy and decommissioning activities required improved material performance and technologies.The most important outcome of CRP was the exchange of information and research co-operation between different institutions and has contributed towards general enhancement of safety by improving waste management practices and their efficiency. The paper presents the most important results and trends revealed by CRP participants. The research contributions of participating organizations will be published as country contributions in a forthcoming IAEA technical publication.

APR1400 원자로내부구조물 종합진동평가 응답측정시험 허용기준

APR1400 RVI CVAP using the non-prototype category II is being conducted to verify integrity of the RVI design and to secure the CVAP technology. The measurement programs are to confirm vibration analysis results for reactor internals during pre-operational and initial startup testing and to determine the safety margin. One of the important basis for the measurement programs is test acceptance criteria. Therefore, this paper is on establishment of response instrumentation test acceptance criteria for APR1400 RVI CVAP. The established acceptance criteria show that the stress criteria of APR1400 RVI are more conservative values than those of the valid prototype plant(Palo Verde unit 1) and, the displacement criteria of the inner barrel assembly and the upper guide structure were established to 0.03 in and 0.01 in, respectively.

Design Optimization and Safety Evaluation of Cross-Sea Bridge Barrier

By comprehensive analysis and design optimization of barrier structure parameters, a new type of beam-and-post steel barrier was invented according to impact test condition and acceptance criteria of cross-sea bridge barrier. Full-scale impact tests and finite elements analysis were conducted to do safty evalution of the barrier. The results show that, ASI value is 1.62 for test and that is 1.67 for FEA, THIV is 30.7km/h for test and that is 31.2km/h for FEA. Working width is 0.88m for test and that is 0.62m for FEA. Occupant risk evaluation index can meet the requirements of level B and the working width can meet the requirements of level W3. Both of tracking and posture of vehicles are well. The study results above show that safety performance of cross-sea bridge barrier can meet or exceed the acceptance criteria. FEA results are consistent with Full-scale impact test, which validate the reliability of FEA. cross-sea bridge barrier can meet the highest test level for beam-and-post steel barrier, which can defend the out-of-control vehicles effectively and help to ensure the bridge safety.

TORC: test plan optimization by requirements clustering

Acceptance testing is a time-consuming task for complex software systems that have to fulfill a large number of requirements. To reduce this effort, we have developed a widely automated method for deriving test plans from requirements that are expressed in natural language. It consists of three stages: annotation, clustering, and test plan specification. The general idea is to exploit redundancies and implicit relationships in requirements specifications. Multi-viewpoint techniques based on RM-ODP (Reference Model for Open Distributed Processing) are employed for specifying the requirements. We then use linguistic analysis techniques, requirements clustering algorithms, and pattern-based requirements collection to reduce the total effort of testing against the requirements specification. In particular, we use linguistic analysis for extracting and annotating the actor, process and object of a requirements statement. During clustering, a similarity function is computed as a measure for the overlap of requirements. In the test plan specification stage, our approach provides capabilities for semi-automatically deriving test plans and acceptance criteria from the clustered informal textual requirements. Two patterns are applied to compute a suitable order of test activities. The generated test plans consist of a sequence of test steps and asserts that are executed or checked in the given order. We also present the supporting prototype tool TORC, which is available open source. For the evaluation of the approach, we have conducted a case study in the field of acceptance testing of a national electronic identification system. In summary, we report on lessons learned how linguistic analysis and clustering techniques can help testers in understanding the relations between requirements and for improving test planning.

Nuclear power plant commissioning experience

In this paper, we present the results of the analysis of the events related to the commissioning of new nuclear power plants and reported to the IAEA International Reporting System database. These results are extracted from a study performed by the European Clearinghouse on Nuclear Power Plant Operational Feedback about the events related to the construction, the manufacturing and the commissioning of new nuclear power plants. After the initial screening of the database, we have analysed in detail 34 events in order to highlight the lessons learned specific to different components and to raise the general recommendations related to the commissioning. This paper summarizes the main lessons learned and the main recommendations concerning the commissioning-related events. These recommendations concern mainly the time of the testing, the scope of the tests, the documentation of the tests, the test acceptance criteria, the systems reconfiguration after commissioning tests and the management of the temporary devices.

Improvements in flattening test performance in high frequency induction welded steel pipe mill

Areas of improvement in the acceptance criteria to the flattening test described in the pipe line international standards (API 5L and ISO 3183) are discussed. The aim is to make the flattening test acceptance criteria for the high frequency induction welded (HFIW) steel pipe clearly stated and defined so that there will be no argument about its interpretation. Recommendations for improving the mill set up to enhance the flattening test performance are also presented based on practical implementation in Saudi Steel Pipe Company. The process capability index is also used as quantitative tool to measure and monitor the performance of the flattening test using the height of the first weld crack as a basis of measurement.

Points to Consider when Establishing Drug Product Specifications for Parenteral Microspheres

Drug product specifications are a critical element of a good control strategy. Parenteral microsphere products are complex dosage forms, requiring careful development of test methods and acceptance criteria for the specifications. In particular, the in vitro release test method and acceptance criteria require rigorous scientific consideration and should be developed with an eye toward understanding the mechanisms of drug release. The final specifications need to ensure the safety, identity, strength, performance, and quality of the drug product at release and during storage through the end of its shelf-life. The specification limits are typically established based upon regulatory guidance, available data from the manufacturing process (process capability), from non-clinical, clinical, and stability studies.