Ring Testing Research Articles

Mixed compensation for the testing of large convex aspheres

Since the testing of convex mirrors often requires a compensator with a larger aperture than the mirror under test, this is undoubtedly a trade-off not worth pursuing. Moreover, for surfaces with higher levels of asphericity, it further escalates the challenges in testing. In this study, high-accuracy testing of large convex aspheric surfaces with rotary symmetry was achieved via a method that combines sub-aperture stitching and Computer-Generated Holograms (CGH) compensation testing. Applying the methodology outlined in this study, practical testing was conducted on a large-aperture convex aspheric mirror with a diameter of 538 mm. The outcomes demonstrated that the center testing data and the outer ring testing data were stitched by the stitching algorithm to obtain the surface error of the full-aperture. The results were compared to those of Luphoscan and compensation testing, with a residual Root Mean Square (RMS) less than λ/20 (λ = 632.8 nm). Finally, the error analysis of the entire testing process showed that the accuracy was better than λ/50. The results demonstrate that the method can achieve highly accurate test of large convex aspheric surfaces.

The Need and a Vision for a Diagnostic Assay Validation Network

Plant biosecurity depends heavily on early detection of biological pest and disease threats and accurate diagnosis of causal agents. The information from these activities is disseminated and communicated with decision makers to promote effective mitigation. In the United States, most land-grant university, state, and private diagnostic and expert pest identifier labs are successfully networked via the U.S. Department of Agriculture Animal Plant Health Inspection Service, Plant Protection and Quarantine (USDA APHIS PPQ; https://www.aphis.usda.gov/ ), the National Plant Diagnostic Network (NPDN; https://www.npdn.org ), and the National Clean Plant Network (NCPN; https://www.nationalcleanplantnetwork.org/ ). These organizations provide access to training, shared protocols, and standardized communications. For example, the NPDN has secure communications tools that network leadership built into its IT infrastructure and deploys a formal communications process and protocol for regulatory and high-risk samples. Additionally, the diagnostic networks adopt protocols from regulatory organizations such as the USDA-APHIS, European and Mediterranean Plant Protection Organization (EPPO), North American Plant Protection Organization (NAPPO), and other international and national plant protection organizations (NPPOs). However, plant health diagnosticians also need access to validated protocols for endemic and nonregulated organisms. Although there is strong networking of diagnostic laboratories, plant disease diagnostic assay development and validation are siloed, representing a critical gap in our biosecurity infrastructure, especially for new or emerging pathogens. Most assays are developed in independent research labs and then chosen independently by the end-use laboratory. Assay developers, those who provide reference materials, labs that can provide ring testing for validation, and assay end users could be connected and integrated for more streamlined operations. Terminology and validation protocols need to be standardized within the United States and harmonized with our trade partners to ensure understanding. The ideal would be availability of standard, taxon-specific validation protocols, essential reference materials, and appropriate control materials for use to quickly develop and deploy assays in emergencies, as well as for day-to-day testing. This perspective article provides a summary of principles of assay validation, fitness-for-purpose concepts, and the need for continuous evaluation of assay performances. We describe the existing capacity and resources needed to efficiently develop, validate, and use diagnostic tests, as well as the inefficiencies and resource shortfalls currently faced. We propose development of a Diagnostic Assay Validation Network (DAVN) system to coordinate resources at the national level and harmonize with our partners at the international level. Here, we outline a project to set up the DAVN with the objectives of standardizing terminology and statistics and facilitating location of reference materials used in diagnostic assay development and validation via a portal of tools designed by and for the plant disease research and extension community. Although many of the concepts are also relevant to insects and other pests, the focus of this article is primarily plant pathogens. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Comparison of arterial storage conditions for delayed arterial ring testing

ObjectiveArterial ring testing is the gold standard for measuring arterial function. Increased arterial tone through arterial contraction and impaired endothelial relaxation (endothelial dysfunction) are key metrics of impaired arterial health in peripheral arterial disease (PAD). To allow for comparative testing of arteries during standard laboratory hours, storage buffers and conditions have been used to extend the functional life of arteries. Various storage conditions have been compared, but there has not been a robust comparison or validation in human arteries. The objective of this work is to optimize storage of arterial segments for endothelial cell (EC) testing in a murine model and to test EC function in human PAD arteries. We hypothesized that certain storage conditions would be superior to others. MethodsHealthy murine aortas were harvested from 10- to 14-week-old C57/Bl6J male and female mice and compared under different storage protocols (24 hours) to immediate arterial testing. The storage conditions tested were: Opti-MEM (37°C or 4°C), Krebs-HEPES with 1.8 mmol/L or 2.5 mmol/L calcium (4°C), or Wisconsin (WI) solution at 4°C. Vascular function was evaluated by isometric force testing. Endothelium-dependent and -independent relaxation were measured after precontraction with addition of methacholine or sodium nitroprusside, respectively. Arterial contraction was stimulated with potassium chloride or phenylephrine. Analysis of variance was used to determine significance compared with immediate testing with P < .05. Under institutional review board approval, 28 PAD arteries were collected at amputation and underwent vascular function testing as described. Disturbed flow conditions were determined by indirect (upstream occlusion) flow to the harvested tibial arteries. Stable flow arteries had in-line flow. Arterial calcification was quantified manually as present or not present. ResultsWe found that 4°C WI and 37°C Opti-MEM best preserved endothelium-dependent relaxation and performed similarly to immediately testing aortas (termed fresh for freshly tested) (P > .95). Other storage conditions were inferior to freshly tested aortas (P < .05). Vascular smooth muscle function was tested by endothelial-independent relaxation and contractility. All storage conditions preserved endothelial-independent relaxation and contractility similar to freshly tested arteries. However, 4°C WI and 37°C Opti-MEM storage conditions most closely approximated the maximum force of contraction of freshly tested arteries in response to potassium chloride (P > .39). For human arterial testing, 28 tibial arteries were tested for relaxation and contraction with 16 arteries with peripheral artery occlusive disease (PAD with disturbed flow) and 12 without peripheral artery occlusive disease (PAD with stable flow), of which 14 were calcified and 14 were noncalcified. Endothelial-dependent relaxation data was measurable in 9 arteries and arterial contraction data was measurable in 14 arteries. When comparing flow conditions, arteries exposed to disturbed flow (n = 4) had significantly less relaxation (2% vs 59%; P = .03) compared with stable flow conditions (n = 5). In contrast, presence the (n = 6) or absence of calcification (n = 3) did not impact arterial relaxation. Arterial contraction was not different between groups in either comparison by flow (n = 9 disturbed; n = 5 stable) or calcification (n = 6 present; n = 8 absent). ConclusionsIn healthy murine aortas, arterial storage for 24 hours in 4°C WI or 37°C Opti-MEM both preserved endothelium-dependent relaxation and maximum force of contraction. In human PAD arteries stored in 4° WI, flow conditions before arterial harvest, but not arterial calcification, led to differences in arterial relaxation in human PAD arteries. Arterial contractility was more robust (11/28 arteries) compared with arterial relaxation (7/28 arteries), but was not significantly different under flow or calcification parameters. This work defines ideal storage conditions for arterial ring testing and identifies that EC dysfunction from disturbed flow may persist in delayed ex vivo arterial testing.

Food analysis: a practical guide

Food analysis: a practical guide

A Novel Testing Method to Quantify Mechanical Properties of the Intact Annulus Fibrosus Ring From Rat-Tail Intervertebral Discs.

The annulus fibrosus is the ring-like exterior of the intervertebral disc, which is composed of concentrically organized layers of collagen fiber bundles. The mechanical properties of the annulus have been studied extensively; however, tests are typically performed on extracted fragments or multilayered samples of the annulus and not on the annulus as a whole. The purpose of this study was twofold: (1) to develop a novel testing technique to measure the mechanical properties of the intact, isolated annulus; and (2) to perform a preliminary analysis of the rate-dependency of these mechanical properties. Twenty-nine whole annulus ring samples were dissected from 11 skeletally mature Sprague Dawley rat tails and underwent a tensile failure test at either 2%/s (n = 16) or 20%/s (n = 13). Force and displacement were sampled at 100 Hz and were subsequently normalized to stress and strain. Various mechanical properties were derived from the stress-strain curves and statistically compared between the rates. All mechanical variables, with the exception of initial failure stress, were found to be unaffected by rate. Interestingly, initial failure stress was higher for samples tested at the slower rate compared to the higher rate which is atypical for viscoelastic tissues. Although in general rate did not appear to impact the annulus ring response to tensile loading, this novel, intact annular ring testing technique provides an alternative way to quantify mechanical properties of the annulus.

A theoretically-based novel protocol for the analytic treatment of the glass failure stresses associated with coaxial double ring test method

With the aim of validating a new standardized Coaxial Double Ring testing procedure, without overpressure and with fixed geometry, an ad hoc theoretical approach has been proposed here to rearrange the laboratory outcomes accounting for the effects of the geometric non-linearities associated with such a testing configuration. By borrowing this idea, once the experimental values of the failure load have been determined, it has been possible to obtain an expression in closed form (fully defined by only two coefficients) of the maximum tensile stress (σmax) in the core of the specimen. Following this, in order to make the laboratory outcomes comparable and homogeneous, the σmax-values have been then re-scaled to a common reference condition (equibiaxial stress on a reference area, σeqbx), by means of the use of a correction coefficient (K) able to determine, under a condition of equal probability of failure, the effective area (Aeff) of the tested specimens. After being corrected to account for the effects of the stress corrosion cracking (static fatigue effect), all re-scaled data have been finally interpreted using a Weibull-type statistical distribution to determine the main fractile values of the glass strength. Doing so, despite some unavoidable approximations, this procedure furnished a highly effective means of determining the bending strength of float glass. Unlike the pure numerical approach proposed in codes and literature, which requires to correct the experimental data via FEM simulation, the rationale behind the proposed approach is in fact to elaborate the experimental data through an analytic treatment of the problem, which would greatly facilitate the interpretation of the data as well as the standardization of the testing procedure.

Qualitative Perceptions of Dapivirine VR Adherence and Drug Level Feedback Following an Open-Label Extension Trial.

There continues to be a need for HIV prevention options that women can initiate and use autonomously. The dapivirine vaginal ring (VR) has been shown to have a favorable safety profile and reduce the risk of HIV-1 acquisition. We report on women's experiences with VR adherence during the MTN-025/HIV Open-label Prevention Extension (HOPE) study and responses to Residual Drug Level (RDL) results. Ten women at each of the 6 HOPE research sites in Lilongwe, Malawi; Durban (2 sites) and Johannesburg, South Africa; Kampala, Uganda; and Chitungwiza, Zimbabwe, were randomly selected (n = 60). After confirmation of eligibility criteria, in-depth interviews were conducted where available RDL results were presented. Many women with low RDL release measurements deflected blame onto other factors (the ring, the drug, and faulty testing machines) and distrust of the testing method. The disclosure of RDL results enabled some users to discuss their challenges experienced (fear of partner objections, perceived side effects, and removals during menses). Consistent users reported important motivators (support from others, protection from HIV, and enhanced sexual experiences from the VR). The VR provided a sense of security for some women; however, adherence was still challenging for others regardless of it being a female controlled, long-acting HIV prevention technology. Adherence measurements may not be sustainable in the real-world implementation of the VR, although they can be seen as a benefit as they provide a better understanding of actual product use and provide women with a platform to discuss their experiences.

Constant Volume Ring Shear Specimen Trimming and Testing

The constant volume ring shear (CVRS) apparatus can use intact/undisturbed specimens to measure the peak and residual undrained shear strengths to estimate the post-peak strength reduction for seismic stability and permanent deformation analyses. A trimming apparatus and specimen container were fabricated to allow the trimming of an intact annular specimen directly into a container that is used for the shearing phase of the test. This article describes the specimen trimming, recommendations for handling and converting the trimming apparatus to the shearing container, which can be done either by hand or with a specially prepared trimmer holder, and suggestions for maintaining an undrained or constant volume shear condition. CVRS undrained peak and residual shear strengths for soils with different plasticity and clay size fractions are presented, and they are in agreement with peak undrained strength ratios from direct simple shear tests. This article also introduces correlations for peak and residual undrained shear strength ratios as a function of plasticity index for verification of future test results and planning level design.

Ready Biodegradability Ring Testing of 4-Isopropylphenol in Different Laboratories for Critical Evaluation of a Biodegradable Reference Substance.

Ready biodegradability is a key property for studying the environmental and ecological risks posed by chemicals, and a reference substance is used to check the reliability of the test results. Traditional reference substances such as aniline, sodium benzoate, and ammonium acetate rapidly degrade even in test systems without inoculum. In this study, 4-isopropylphenol was investigated as a reference candidate. Aerobic biodegradation of 4-isopropylphenol was studied using different methods, and repeatability tests were performed in multiple laboratories. 4-Isopropylphenol met the ready biodegradability passing level in a closed bottle test (OECD 301D) and manometric respirometry test (OECD 301F). No obvious toxicity was found in activated sludge respiration inhibition and biodegradable toxicity control tests. The results of 301F tests performed in 15 Chinese laboratories were compared using statistical robustness analyses and Z-scores. The robust average 28-d biodegradability rate for 4-isopropylphenol was 80.3%, and the relative standard deviation was 9.20%. The data from the 15 laboratories consistently indicated that 4-isopropylphenol was readily biodegradable, except for an "unsatisfactory" outlier result from 1 laboratory. The degradation kinetics of 4-isopropylphenol were derived from a logistic model, which had a good fit for the degradation curve. The biodegradation lag phase was 2.3 d (range 2-5 d), and the pass level was attained at 6.5 d on average (range 2-9 d), which met the 10-d window requirement. The biodegradation rate at 28 d was 75.3% (range 64.0%-95.1%). The ready biodegradability of 4-isopropylphenol indicates that it will be more appropriate as a reference chemical than other reference compounds used for investigating the biodegradability of chemicals. Integr Environ Assess Manag 2021;17:562-572. © 2020 SETAC.

Results of 2-Year Ring Testing of a Semifield Study Design to Investigate Potential Impacts of Plant Protection Products on the Solitary Bees Osmia Bicornis and Osmia Cornuta and a Proposal for a Suitable Test Design.

There are various differences in size, behavior, and life history traits of non‐Apis bee species compared with honey bees (Apis mellifera; Linnaeus, 1758). Currently, the risk assessment for bees in the international and national process of authorizing plant protection products has been based on honey bee data as a surrogate organism for non‐Apis bees. To evaluate the feasibility of a semifield tunnel test for Osmia bicornis (Linnaeus, 1758) and Osmia cornuta (Latreille, 1805), a protocol was developed by the non‐Apis working group of the International Commission for Plant‐Pollinator Relationships, consisting of experts from authorities, academia, and industry. A total of 25 studies were performed over a 2‐yr period testing a replicated control against a replicated positive control using either a dimethoate or diflubenzuron treatment. Studies were regarded to be valid, if ≥30% of released females were found to occupy the nesting units in the night/morning before the application (establishment). Thirteen studies were regarded to be valid and were analyzed further. Parameters analyzed were nest occupation, flight activity, cell production (total and per female), cocoon production (total and per female), emergence success, sex ratio, and mean weight of females and males. Dimethoate was a reliable positive control at the tested rate of 75 g a.i./ha, once >30% females had established, displaying acute effects such as reduction in flight activity, increase in adult mortality (shown by nest occupation), and reproduction ability of the females (total cell and cocoon production). On the other hand, no effects on larval and pupal development were observed. The growth regulator diflubenzuron had statistically significant effects on brood development, causing mortality of eggs and larvae at a rate of approximately 200 g a.i./ha, whereas fenoxycarb did not cause any significant effects at the tested rates of 300 and 600 g a.i./ha. In conclusion, the ring‐test protocol proved to be adequate once the study comprised a well‐established population of female Osmia bees, and the results improved in the second year as the laboratories increased their experience with the test organism. It is noted that the success of a study strongly depends on the experience of the experimenter, the crop quality, the quality of the cocoons, and the weather conditions. Based on these finding, recommendations for a semifield study design with Osmia spp. are proposed. Environ Toxicol Chem 2021;40:236–250. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

On the use of small ring testing for the characterisation of elastic and yield material property variation in additively manufactured materials

• Material properties are shown to vary over an additive manufacture build volume. • Small ring samples are used here to investigate a Ti-6Al-4V alloy. • Analytical and numeric methodologies are developed for tensile data interpretation. The present work introduces a small volume, high throughput testing method that may be used to quickly, and with high spatial fidelity, investigate local material properties in additively manufactured materials. A case study application is presented here, considering components made from the alloy Ti-6Al-4V by the powder bed fusion process. Novel tensile small ring samples are produced at multiple locations over the print volume and are tested in order to estimate local tensile material responses. An inverse method is implemented in order to estimate representative material properties at each testing location by optimising initial values against sequential finite element model results. Initial estimates themselves are found through a geometrically non-linear semi-analytical model that approximates elastic material response. A good level of repeatability is noted between small ring tests conducted at specific build locations, suggesting a limited effect of build height on constitutive response and robust testing/analysis methodology. Small ring tests indicate a mean Young's modulus of 82.83 GPa (with a standard deviation of 4.57 GPa) and a mean yield stress of 655.58 MPa (with a standard deviation of 115.73 MPa). Full sized “conventional” tests, published in the author's previous work, indicate a Young's modulus of 114.45 GPa and a yield stress of 771.266 MPa. Limited fractography has indicated that there is a wide variation in porosity across the build volume, suggesting that the deviations in local material properties are due to the use of a reduced print volume in specimen manufacture.

845. Children with Clinical Plasmodium falciparum Infection Have Increased Sharing of Haplotypes with Household Members as well as Temporally Proximal, Symptomatic Peers

BackgroundFalciparum malaria transmission has failed to decline in proportion to control efforts in certain regions such as Bungoma county, western Kenya. One proposed strategy to eradicate malaria is ring testing and treatment; however, it remains unknown whether infections spread locally or if asymptomatically infected household members are a risk factor for clinical disease.MethodsFrom April 2013 to June 2014, we enrolled 442 cases (RDT+ children hospitalized with malaria) and 442 matched controls; all household members of cases and controls were also enrolled and tested, of which 13.6% (n = 608/4449) were RDT+. From each RDT+ participant, parasite gDNA was PCR-amplified at both Pf circumsporozoite protein (csp) and apical membrane antigen 1 (ama1) loci, amplicons sequenced on an Illumina Miseq, and haplotypes inferred using dada2.ResultsWe identified 120 csp and 180 ama1 unique haplotypes (Figure 1). We evaluated the genetic distance between infected individuals using three novel indices: sharing of parasite haplotypes on binary and proportional scales and the L1 norm. Case children median [IQR] binary/proportional sharing of both csp and ama1 haplotypes was significantly increased with members of their origin household (e.g., csp binary sharing: origin = 50.3 [0–87.5] vs. similar household = 0 [0–50.3]; P = 0.01; Wilcoxon sign-rank test), indicating that cases are more likely to share haplotype-identical parasites with members of their own household (Figure 2). We also computed population-level haplotype sharing indices for all pairs of case children and observed no association between genetic relatedness and geographic distance. In contrast, we identified a strong inverse relationship between haplotype sharing and temporal distance, which we exploited to identify the molecular signature of an outbreak (Figure 3).ConclusionOverall, these findings suggest that, although haplotype sharing is more common within households, temporal rather than geographic proximity predicts parasite genetic similarity. The observation that identical haplotype combinations are found nearly simultaneously across the study area implies that ring testing approaches may not effectively reduce transmission. Disclosures All Authors: No reported Disclosures.

Weight-of-Evidence Approach for Assessing Removal of Metals from the Water Column for Chronic Environmental Hazard Classification.

The United Nations and the European Union have developed guidelines for the assessment of long-term (chronic) chemical environmental hazards. This approach recognizes that these hazards are often related to spillage of chemicals into freshwater environments. The goal of the present study was to examine the concept of metal ion removal from the water column in the context of hazard assessment and classification. We propose a weight-of-evidence approach that assesses several aspects of metals including the intrinsic properties of metals, the rate at which metals bind to particles in the water column and settle, the transformation of metals to nonavailable and nontoxic forms, and the potential for remobilization of metals from sediment. We developed a test method to quantify metal removal in aqueous systems: the extended transformation/dissolution protocol (T/DP-E). The method is based on that of the Organisation for Economic Co-operation and Development (OECD). The key element of the protocol extension is the addition of substrate particles (as found in nature), allowing the removal processes to occur. The present study focused on extending this test to support the assessment of metal removal from aqueous systems, equivalent to the concept of "degradability" for organic chemicals. Although the technical aspects of our proposed method are different from the OECD method for organics, its use for hazard classification is equivalent. Models were developed providing mechanistic insight into processes occurring during the T/DP-E method. Some metals, such as copper, rapidly decreased (within 96 h) under the 70% threshold criterion, whereas others, such as strontium, did not. A variety of method variables were evaluated and optimized to allow for a reproducible, realistic hazard classification method that mimics reasonable worst-case scenarios. We propose that this method be standardized for OECD hazard classification via round robin (ring) testing to ascertain its intra- and interlaboratory variability. Environ Toxicol Chem 2019;38:1839-1849. © 2019 SETAC.

Stress Corrosion Cracking of AZ91 + xCe Alloy Using Proof Ring Test in ASTM D1384 and NaCl-K2CrO4 Solutions

The effect of cerium addition on AZ91 magnesium alloy and its influence on stress corrosion cracking (SCC) were studied using constant load proof ring testing NaCl-K2CrO4 and ASTM D1384 solutions at 70 and 80% of yield stress, respectively. The investigation revealed that the optimum grain refinement of desired phases occurred with 0.5% addition of cerium. The addition levels of cerium above 1.5 wt.% to AZ91 alloy resulted in premature failures due to poor SCC resistance in both solutions (K2CrO4 and ASTM D1384 solutions). The microstructural studies of the experimental alloys were characterized by using optical and scanning electron microscopy. The elemental compositions of cerium-added AZ91 magnesium alloys were studied by energy-dispersive spectroscopy. The results indicate that the mode of SCC failure was found to be transgranular in nature along with secondary cracks containing cleavages which resulted from the hydrogen embrittlement and anodic dissolution phenomena. The AZ91 alloy with 0.5 wt.% cerium exhibits better mechanical properties and high stress corrosion resistance.

Small ring testing of high temperature materials

In service components such as steam pipes, pipe branches, gas and steam turbine blades, etc. which operate in engineering applications such as power plant, aero-engines, chemical plant etc., can operate at temperatures which are high enough for creep to occur. Often, only nominal operating conditions (i.e. pressure, temperatures, system load, etc.) are known and hence precise life predictions for these components, which may be complex in terms of geometry or weld characteristics, are not possible. Within complex components it can also be the case that the proportion of the material creep life consumed may vary from position to position within the component. It is therefore important that non-destructive techniques are available for assisting in the making of decisions on whether to repair, continue operating or replace certain components. Small specimen creep testing is a technique which can allow such analyses to be performed. Small samples of material are removed from the component to make small creep test specimens. These specimens can then be tested to give information on the remaining creep life of the component. This paper presents the results of small ring specimens tested under creep conditions and shows the comparison to standard (full size) creep testing for materials used under high temperature in industry.

Influence of surface martensite layer on hydrogen embrittlement of Fe-Mn-C-Mo steels in wet H2S environment

This study investigated the effect of thermally induced surface martensite layer on hydrogen embrittlement of Fe-16Mn-0.4C-2Mo (wt.%) (16Mn) and Fe-25Mn-0.4C-2Mo (wt.%) (25Mn) steels through slow strain rate stress corrosion cracking testing and proof ring testing in wet H2S environment. The 16Mn steel had a surface layer of less than 150 μm in depth containing ε-martensite, α′-martensite and austenitic twins. The martensite layer is found to reduce the hydrogen embrittlement resistance of the steel. In comparison, the 25Mn steel developed a full α′-martensite surface layer, which exhibited practically nil effect on the hydrogen embrittlement resistance of the steel. The ε-martensite provides much larger interface areas with the mechanical twins of the austenite in the 16Mn steel than the α′-martensite/austenite interfaces in the 25Mn steel. These interfaces are hydrogen trapping sites and are prone to initiate surface cracks, as observed in the scanning electron microscope. The formation of the cracks is attributed to hydrogen concentration at the ε-martensite and austenitic twin interfaces, which accelerates material fracture.

Validation of an invitro sun protection factor (SPF) method in blinded ring-testing.

The objective of this work was to investigate the utility of a new invitro SPF test method in blinded ring-testing, against new ISO acceptance criteria. Twenty four blinded, commercial, emulsion-type, primary sunscreen products, covering the full range of labelled SPF in Europe (SPF6 - 50+), were tested by three test institutes using the current ISO24444:2010 In Vivo SPF Test Method and simultaneously by three separate test laboratories using a new candidate invitro SPF test method, developed under the leadership of Cosmetics Europe (CE). The resulting relationship between invitro SPF and invivo SPF values was then compared with acceptance criteria developed recently by the International Standards (ISO) TC217/WG7 Sun Protection Test Methods Working Group. Analysis of the mean inter-laboratory invitro and mean inter-institute invivo SPF values revealed a strong correlation between invitro and invivo values, with a Pearson correlation coefficient of r2 =0.88 (P<0.0001), a slope of 1.01 and a non-significant intercept (-1.48; P=0.62). When these data were compared to the new ISO WG7 acceptance criteria, method bias was found to be extremely low and over 95% of the coupled data lay within the model 'funnel' (defined by upper and lower confidence intervals). In conclusion, the results of blinded ring testing and comparison to new ISO WG7 acceptance criteria indicate that a new invitro SPF test method meets (and exceeds) these minimum criteria and is an interesting candidate for possible deployment as an industry test methodology.

Online Ring Testing to Elicit the Cause of Underdispersion in Seed Germination Tests

According to International Rules for Seed Testing, a germination test is performed with 400 seeds, subdivided into four replicates of 100 seeds. The empirical variance between the four replicate results was found by many authors to be smaller than random sampling variation. Hypotheses for sources for this underdispersion were developed, but no experimental proof was possible, as the population's true germination value is unknown. To overcome this obstacle, we performed two online ring tests with computer‐generated seedling images. Seedlings had to be classified as normal, if the shoot/root ratio was between 0.5 and 2.0, otherwise as abnormal. Results showed significantly smaller variances between empirical replicate results than between true replicate values, confirming underdispersion. Rates of false normal and false abnormal classification of seedlings were 19.5 and 3.5%, respectively. Error rates are different between analysts and depend on the true replicate value. In replicates with many abnormal seedlings, the false normal rate is higher and the false abnormal rate is lower than in samples with few abnormal seedlings. This is the source of underdispersion and a direct result of decisions made by seed analysts. Pooling of replicate results of all analysts and recombining showed that underdispersion can be reduced significantly when each replicate is tested by a different analyst. Hence, replicates should be blinded and every replicate evaluated by another analyst.

Small Ring Testing of High Temperature Materials

In service components such as steam pipes, pipe branches, gas and steam turbine blades, etc. which operate in engineering applications such as power plant, aero-engines, chemical plant etc., can operate at temperatures which are high enough for creep to occur. Often, only nominal operating conditions (i.e. pressure, temperatures, system load, etc.) are known and hence precise life predictions for these components, which may be complex in terms of geometry or weld characteristics, are not possible. Within complex components it can also be the case that the proportion of the material creep life consumed may vary from position to position within the component. It is therefore important that non-destructive techniques are available for assisting in the making of decisions on whether to repair, continue operating or replace certain components. Small specimen creep testing is a technique which can allow such analyses to be performed. Small samples of material are removed from the component to make small creep test specimens. These specimens can then be tested to give information on the remaining creep life of the component. This paper presents the results of small ring specimens tested under creep conditions and shows the comparison to standard (full size) creep testing for materials used under high temperature in industry.

Characterisation of Ring Testing in the Design of Offshore Oil Transportation Systems

The manufacturing procedure qualification tests (MPQT) of offshore pipelines projects has recently started to rely on ring collapse tests, which consist in testing a short section (50 mm) of a full scale joint. This approach is capable of providing valuable insight into the collapse behaviour of offshore pipelines and has practical, financial and logistic benefits.Detailed analytical and numerical work has been carried out in order to understand the collapse mechanisms and the influence of several parameters, like geometry, material strength and seal friction, on the collapse behaviour has been investigated.It is found that the shape of the initial imperfection and the seal friction can both affect the collapse and produce a variation in the value of the collapsing pressure.