Wood surfaces protected with transparent multilayer UV-cured coatings reinforced with nanosilica and nanoclay. Part II: Application of a standardized test method to study the effect of relative humidity on scratch resistance

2014 ◽  
Vol 11 (6) ◽  
pp. 993-1011 ◽  
Author(s):  
William Nguegang Nkeuwa ◽  
Bernard Riedl ◽  
Véronic Landry
Keyword(s):  
Relative Humidity ◽  
Standardized Test ◽  
Scratch Resistance ◽  
Test Method ◽  
Wood Surfaces

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.

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 The impact of the top coating on the mechanical properties of lacquered wood surfaces

2012 ◽  
pp. 87-100
Author(s):  
Milan Jaic ◽  
Tanja Palija
Keyword(s):  
Mechanical Properties ◽  
Wood Species ◽  
Abrasion Resistance ◽  
Direct Contact ◽  
Quercus Robur ◽  
Scratch Resistance ◽  
Indentation Hardness ◽  
Polyurethane Coating ◽  
The Impact ◽  
Wood Surfaces

This paper investigates the impact of the top coating on the basic mechanical properties of a lacquered surface, including indentation hardness, scratch resistance and abrasion resistance. Three types of the top coating were used, including a 2K polyurethane coating, a 2K acrylate-isocyanate coating and a 2K alkyd-urethane coating. Samples of two wood species, spruce (Picea abies Karst.) and oak (Quercus robur L.), were used in this study, in order to determine whether the wood species, which is not in direct contact with the top coating, has an impact on the mechanical properties of a lacquered surface. The samples coated with a 2K acrylate-isocyanate coating showed the highest values of indentation hardness, in the samples of both wood species (1.34 N for spruce; 1.4 N for oak). The samples coated with a 2K alkyd-urethane coating showed the highest values of scratch resistance (20 N for both wood species) and abrasion resistance (mass loss of 480 mg after 700 cycles for both wood species). The results have shown that the wood species does not affect the value of indentation hardness, scratch resistance and abrasion resistance of a lacquered surface.

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.

Restrained Shrinkage Behavior of Concrete under Different Environmental Conditions

2014 ◽  
Vol 941-944 ◽  
pp. 835-841 ◽  
Author(s):  
Zhi Tao Chen ◽  
Mao Guang Li ◽  
Ying Zi Yang ◽  
Qi Liu
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Test Method ◽  
Mineral Admixtures ◽  
Ring Test ◽  
Test Duration ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking ◽  
Higher Temperature ◽  
Shrinkage Behavior

The ring test method is used to evaluate the behavior of concrete under restrained shrinkage. Four kinds of environmental conditions (20±1°C, RH60±5%; 35±1°C, RH60±5%; 50±1°C, RH15±5%; 65±1°C, RH15±5%) were designed to investigate the effect the environmental condition on the shrinkage behavior of concrete prepared with different kinds of mineral admixtures. The results show that higher temperature and lower relative humidity can increase the risk of shrinkage cracking. The addition of different mineral admixtures increases the shrinkage of concrete at room conditions. In the case of higher temperature and lower relative humidity, the addition of mineral admixtures can delay the shrinkage cracking in the test duration.

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.

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