Validation of a new standardized test method for the freshwater amphipodHyalella azteca: Determining the chronic effects of silver in sediment

2016 ◽  
Vol 35 (10) ◽  
pp. 2430-2438 ◽  
Author(s):  
Lisa N. Taylor ◽  
Lesley Novak ◽  
Martina Rendas ◽  
Paula M.C. Antunes ◽  
Rick P. Scroggins
Keyword(s):  
Standardized Test ◽  
Test Method ◽  
Chronic Effects

scholarly journals Laboratory Test to Evaluate the Resistance of Cementitious Materials to Biodeterioration in Sewer Network Conditions

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 686
Author(s):  
Amr Aboulela ◽  
Matthieu Peyre Lavigne ◽  
Amaury Buvignier ◽  
Marlène Fourré ◽  
Maud Schiettekatte ◽  
...  
Keyword(s):  
Calcium Aluminate ◽  
Standardized Test ◽  
Performance Indicator ◽  
Cementitious Materials ◽  
Test Method ◽  
Sustainable Construction ◽  
Public Health Issue ◽  
Sulfur Source ◽  
Test Protocol ◽  
Wide Range

The biodeterioration of cementitious materials in sewer networks has become a major economic, ecological, and public health issue. Establishing a suitable standardized test is essential if sustainable construction materials are to be developed and qualified for sewerage environments. Since purely chemical tests are proven to not be representative of the actual deterioration phenomena in real sewer conditions, a biological test–named the Biogenic Acid Concrete (BAC) test–was developed at the University of Toulouse to reproduce the biological reactions involved in the process of concrete biodeterioration in sewers. The test consists in trickling a solution containing a safe reduced sulfur source onto the surface of cementitious substrates previously covered with a high diversity microbial consortium. In these conditions, a sulfur-oxidizing metabolism naturally develops in the biofilm and leads to the production of biogenic sulfuric acid on the surface of the material. The representativeness of the test in terms of deterioration mechanisms has been validated in previous studies. A wide range of cementitious materials have been exposed to the biodeterioration test during half a decade. On the basis of this large database and the expertise gained, the purpose of this paper is (i) to propose a simple and robust performance criterion for the test (standardized leached calcium as a function of sulfate produced by the biofilm), and (ii) to demonstrate the repeatability, reproducibility, and discriminability of the test method. In only a 3-month period, the test was able to highlight the differences in the performances of common cement-based materials (CEM I, CEM III, and CEM V) and special calcium aluminate cement (CAC) binders with different nature of aggregates (natural silica and synthetic calcium aluminate). The proposed performance indicator (relative standardized leached calcium) allowed the materials to be classified according to their resistance to biogenic acid attack in sewer conditions. The repeatability of the test was confirmed using three different specimens of the same material within the same experiment and the reproducibility of the results was demonstrated by standardizing the results using a reference material from 5 different test campaigns. Furthermore, developing post-testing processing and calculation methods constituted a first step toward a standardized test protocol.

scholarly journals Development of an in vitro test procedure for the characterization of left atrial appendage occluder devices

2019 ◽  
Vol 5 (1) ◽  
pp. 461-463
Author(s):  
Finja Borowski ◽  
Sebastian Kaule ◽  
Stefan Siewert ◽  
Klaus-Peter Schmitz ◽  
Michael Stiehm ◽  
...  
Keyword(s):  
Left Atrial ◽  
Left Atrial Appendage ◽  
Standardized Test ◽  
Test Procedure ◽  
Test Method ◽  
Atrial Appendage ◽  
In Vitro Test ◽  
Watchman Device ◽  
Vitro Test

AbstractThe implantation of an occluder in the left atrial appendage (LAA) is an emerging therapy for the treatment of patients suffering from atrial fibrillation and with a contraindication to oral anticoagulation. The LAA occluder (LAAO) provides a reduction of the potential risk of strokes by thromboembolism. Currently, only a few CE-approved devices are available on the market and the number of clinical trials is comparatively low. Furthermore, there is currently no standardized test method available for testing functionality of the occluder, especially for testing safe anchorage and permeability. Therefore, the aim of this study is to establish an in vitro test method to prove anchorage mechanism and permeability regarding thromboembolism of the LAAO under physiological conditions. A standardized technical and fully parameterized silicone model of a LAA, based on studies of different morphologies and sizes, was developed. The LAA model was mounted onto the left atrial chamber of a commercial pulse duplicator system to simulate physiological hemodynamic conditions. The test was performed using the Watchman device (Boston Scientific, USA; size: 31 mm). The inner implantation diameter of the LAA model was designed according to a target compression of 10% for the Watchman device in the implanted configuration. Furthermore, thrombus-like particles (n=150, d=1,7±0,05 mm) were added to represent the flushing of thrombi out of the LAA after device implantation. Within several cycles it was confirmed that no particles were washed out of the LAA model with the implanted occluder leading to a full protection against thromboembolism. It could also be shown that the occluder is firmly anchored in the LAA. Pressure measurements with sensors in the left atrium and in the LAA distal to the occluder could also show that the occluder has no influence on the pressure conditions in the LAA.

Reliability of Miniature Concrete Prism Test in Assessing Alkali-Silica Reactivity of Moderately Reactive Aggregates

2020 ◽  
Vol 2674 (4) ◽  
pp. 23-29
Author(s):  
Harish Konduru ◽  
Prasad Rangaraju ◽  
Omar Amer
Keyword(s):  
False Positive ◽  
Standardized Test ◽  
False Negative ◽  
Test Method ◽  
Test Procedures ◽  
Concrete Prism ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Mortar Bar ◽  
Concrete Prism Test

Alkali-silica reaction (ASR) is one of the most significant durability issues in concrete structures. Although there are a number of standardized test procedures to evaluate the aggregate reactivity, each method has its own drawbacks. Two of the most common tests that are employed widely are the accelerated mortar bar test (AMBT) (ASTM C1260) and the concrete prism test (CPT) (ASTM C1293). The major issue with the AMBT test is the number of false-positive results from this test associated with high test temperature, rendering the test method unreliable. CPT is one of the most reliable tests for assessing the potential for ASR, but its major disadvantage is the duration of the test involved, which takes one to two years. In this research, a novel test method called the miniature concrete prism test (MCPT) was developed and the effectiveness and reliability of the results assessed when compared with CPT and AMBT. Samples of 26 coarse aggregates and 16 fine aggregates with various reactivity levels were employed for the testing. The test results were compared for MCPT versus CPT, in which 23 out of 26 coarse aggregates and eight out of 16 fine aggregates either passed or failed in both MCPT and CPT. For MCPT versus AMBT, 16 out of 26 coarse aggregates and 13 out of 16 fine aggregates either passed or failed in both MCPT and AMBT. The sensitivity of false-negative and false-positive aggregate sources is discussed and explained briefly.

scholarly journals Tigecycline MIC Testing by Broth Dilution Requires Use of Fresh Medium or Addition of the Biocatalytic Oxygen-Reducing Reagent Oxyrase To Standardize the Test Method

2005 ◽  
Vol 49 (9) ◽  
pp. 3903-3909 ◽  
Author(s):  
Patricia A. Bradford ◽  
Peter J. Petersen ◽  
Mairead Young ◽  
C. Hal Jones ◽  
Mark Tischler ◽  
...  
Keyword(s):  
Standardized Test ◽  
Culture Collection ◽  
Fresh Medium ◽  
Test Method ◽  
Chromatography Analysis ◽  
Mueller Hinton ◽  
Early Peak ◽  
The Media ◽  
Time Kill ◽  
Mueller Hinton Broth

ABSTRACT Tigecycline is a broad-spectrum glycylcycline antibiotic with activity against not only susceptible gram-positive and gram-negative pathogens but also strains that are resistant to many other antibiotics. In the process of determining quality control (QC) limits for the American Type Culture Collection reference strains for tigecycline, a number of inconsistencies in MICs were encountered which appeared to be related to the age of the Mueller-Hinton broth (MHB) medium used in the MIC testing. The objective of this study was to determine the cause of the discrepant MIC results between fresh and aged MHB. The MICs of tigecycline were determined in MHB that was either prepared fresh (<12 h old), prepared and stored at 4°C, stored at room temperature, stored anaerobically, or supplemented with the biocatalytic oxygen-reducing reagent Oxyrase. When tested in fresh media, tigecycline was 2 to 3 dilutions more active against the CLSI-recommended QC strains compared to aged media (MICs of 0.03 to 0.25 and 0.12 to 0.5 μg/ml, respectively). Media aged under anaerobic conditions prior to testing or supplemented with Oxyrase resulted in MICs similar to those obtained in fresh medium (MICs of 0.03 to 0.12 and 0.03 to 0.25 μg/ml, respectively). Time-kill kinetics demonstrated a >3 log10 difference in viable growth when tigecycline was tested in fresh or Oxyrase-supplemented MHB compared to aged MHB. High-pressure liquid chromatography analysis revealed the accumulation of an early peak (oxidative by-product of tigecycline) to be 3.5% in fresh media and 25.1% in aged media after 24 h and that addition of Oxyrase prevented the accumulation of this oxidized by-product. These results suggested that the activity of tigecycline was affected by the amount of dissolved oxygen in the media. The use of fresh MHB or supplementation with Oxyrase resulted in a more standardized test method for performing MIC tests with tigecycline.

scholarly journals Development of a standardized test method for characterizing the stiffness of heel sole segments of sports shoes

2010 ◽  
Vol 2 (2) ◽  
pp. 2801-2804 ◽  
Author(s):  
Mathew James Dickson ◽  
Franz Konstantin Fuss ◽  
Michael Burton
Keyword(s):  
Standardized Test ◽  
Test Method ◽  
Sports Shoes

High-Temperature Interlaminar Tension Test Method Development for Ceramic Matrix Composites

2013 ◽  
Author(s):  
Todd Engel
Keyword(s):  
High Temperature ◽  
Method Development ◽  
Standardized Test ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Test Method ◽  
Test Technique ◽  
Structural Applications

Ceramic Matrix Composite (CMC) materials are an attractive design option for various high-temperature structural applications. In particular, the use of CMC materials as a replacement for state-of-the-art nickel-based superalloys in hot gas path turbomachinery components offers the potential for significant increases in turbine system efficiencies, due largely to reductions in cooling requirements afforded by the increased temperature capabilities inherent to the ceramic material. However, two-dimensional fabric-laminated CMCs typically exhibit low tensile strengths in the thru-thickness (interlaminar) direction, and interply delamination is a concern for some targeted applications. Currently, standardized test methods only address the characterization of interlaminar tensile strengths at ambient temperatures; this is problematic given that nearly all CMCs are slated for service in high-temperature operating environments. This work addresses the development of a new test technique for the high-temperature measurement of interlaminar tensile properties in CMCs, allowing for the characterization of material properties under conditions more analogous to anticipated service environments in order to yield more robust component designs.

Shock Absorbing Characteristics of Floors Used for Dance Exercise

1988 ◽  
Vol 4 (3) ◽  
pp. 282-305 ◽  
Author(s):  
Peter R. Francis ◽  
Michael Leigh ◽  
Aldis Berzins
Keyword(s):  
Standardized Test ◽  
Test Method ◽  
Complex Nature ◽  
Data Sets ◽  
Acceleration Time ◽  
Testing Procedures ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Additional Procedure

The Standardized Test Method for Shock-Absorbing Properties of Playing Surface Systems and Materials (ASTM F-355) was used to evaluate the shock absorbing characteristics of 13 floors used for dance exercise. Acceleration-time histories indicated that the floors differed markedly in their shock absorbing behavior. The complex nature of the acceleration-time histories led to the conclusion that descriptors that have previously been used to quantify shock absorbing data were inadequate for the floors examined in this investigation. An additional procedure was devised in order to examine potentially injurious stresses on a performer while executing a common dance exercise movement performed on each of the 13 floors tested. It was concluded that the two testing procedures evaluated differing aspects of the shock absorbing mechanisms involved in dance exercise. However, a tentative relationship between the two corresponding data sets provided some support for the retention of ASTM F-355 as a reproducible test for the shock absorbing characteristics of floors.

Friction Testing Method for Open-Grated Steel Bridge Decks

2003 ◽  
Vol 1860 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Richard A. Zimmer ◽  
Bouzid Choubane ◽  
Charles R. Holzschuher
Keyword(s):  
Road Safety ◽  
Standardized Test ◽  
Bridge Decks ◽  
Test Method ◽  
State Agencies ◽  
Steel Bridge ◽  
Friction Characteristics ◽  
Testing Method ◽  
Friction Testing ◽  
Highway Planning

For more than four decades, most of the testing methods and studies for the determination or quantification of friction and texture properties have been concerned primarily with concrete and asphalt paved roadways. However, since the focus of such methods has been mainly on paved roads, other traveled surface types, although part of roadway systems, have been overlooked or simply not addressed directly. As travel safety and efficiency are gaining importance to state agencies, it is imperative to include the atypical travel surfaces, such as bridges with open-grated steel decks, in an appropriate measurement program. To this end, the current study was initiated to identify an appropriate method for measuring the friction characteristics on steel bridge decks. An appropriate standardized test method would provide information that can be effectively used in state road safety and management programs. This method would also provide a tool to ensure that all travel surfaces are constructed and maintained with appropriate friction properties. All the results obtained during this investigation indicated that ASTM E-274 can be appropriately used to assess friction characteristics on both paved surfaces and open-grated steel bridge decks. Such information is critical to support informed highway planning and policy and decision making. In addition, the study findings can be used as a basis to revise the current ASTM standard to include open-grated steel bridge decks.

The ASTM International Standard Test Method for Determining the Superplastic Properties of Metallic Materials

2007 ◽  
Vol 551-552 ◽  
pp. 105-110
Author(s):  
Peter N. Comley
Keyword(s):  
Standardized Test ◽  
Constant Strain Rate ◽  
Standard Test ◽  
Test Method ◽  
Test Machine ◽  
Metallic Materials ◽  
Step Method ◽  
Fine Grain ◽  
American Society ◽  
Superplastic Properties

Over the last 40 years there have been many papers published showing superplastic properties of metallic materials. However there has been no standardized test available to assess and compare material, and researchers and companies in the field have devised a number of different methods to show superplastic properties. The value of these properties can vary dependent on the test method used. ASTM International (formerly The American Society for Testing and Materials ) has developed a standardized test method for superplastic properties. The standard is intended for all to use as a common platform for testing, evaluating and publishing superplastic properties to a uniform format, useful for both academia and industry. The paper outlines the main points of the standard, including:- The coupon geometry and the method of clamping the coupon in the grips. The furnace and test machine requirements. The testing conditions and the method of pulling the coupon. The analysis of the load and extension data from the test, and the standard presentation of superplastic properties. The basic superplastic properties of stress versus strain for any particular constant strain rate. The method to determine ‘m’, using a step method at a particular strain. Some data is presented showing how the properties of fine grain Ti-6Al-4V titanium alloy are derived and presented using the standard.

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