scholarly journals The Evaluation of the Detection of Cr(VI) in Leather

Analytica ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 1-13
Author(s):  
Stefan John Davis ◽  
William Robert Wise ◽  
Sandro Recchia ◽  
Andrea Spinazzè ◽  
Maurizio Masi
Keyword(s):  
Supply Chain ◽  
Hexavalent Chromium ◽  
Marked Improvement ◽  
Colorimetric Method ◽  
Test Methods ◽  
Standard Test ◽  
Quantitative Detection ◽  
Current Standard ◽  
Limit Of Quantification ◽  
Low Concentrations

The topic of hexavalent chromium (Cr(VI)) in leather has been debated throughout the whole supply chain for years. However, its significance has recently increased due to proposed changes in European legislation concerned with skin-sensitising substances suggesting that acceptable Cr(VI) concentrations in leather goods should be lowered from 3 mg kg−1 to 1 mg kg−1. The proposition of a stricter limit and current analytical difficulties created the need for a review of current standard test methods. The research presented in this paper investigates both the colorimetric (Part 1) and chromatographic (Part 2) methods under BS EN ISO 17075. The focus of the study was to identify possible sources of interference leading to large statistical variance in results and to define the limit of quantification with respect to the proposed new compliance limit. This study into the colorimetric method has shown that the presence of Cr(III), dyes, and proteins can be significant interferences, becoming critical at low Cr(VI) concentrations. Dilution factors worsen the problem of detecting low concentrations: a reliable quantitative detection of 0.01 mg kg−1 and 0.003 mg kg−1 Cr(VI) in solution are required at the 3 mg kg−1 and 1 mg kg−1 compliance limits in leather, respectively. BS EN ISO 17075 part 1 was shown to be incapable of reliably resolving to 3 mg kg−1 or below in leather. Part 2 shows a marked improvement in detection limits and reliability; however, data suggest that 1 mg kg−1 Cr(VI) is not reliably detectable in leather. Suggested improvements to the established test methods and a possible alternative are discussed.

scholarly journals Comparison of Two Intergranular Corrosion Tests on EN AW-6016 Sheet Material

2021 ◽  
Vol 11 (11) ◽  
pp. 5294
Author(s):  
Peer Decker ◽  
Ines Zerbin ◽  
Luisa Marzoli ◽  
Marcel Rosefort
Keyword(s):  
Optical Microscopy ◽  
Intergranular Corrosion ◽  
Sheet Material ◽  
Test Methods ◽  
Standard Test ◽  
Corrosion Depth ◽  
Corrosion Tests ◽  
Automotive Company ◽  
Test Parameters

Two different intergranular corrosion tests were performed on EN AW-6016 sheet material, an ISO 11846:1995-based test with varying solution amounts and acid concentrations, and a standard test of an automotive company (PV1113, VW-Audi). The average intergranular corrosion depth was determined via optical microscopy. The differences in the intergranular corrosion depths were then discussed with regard to the applicability and quality of the two different test methods. The influence of varying test parameters for ISO 11846:1995 was discussed as well. The determined IGC depths were found to be strongly dependent on the testing parameters, which will therefore have a pronounced influence on the determined IGC susceptibility of a material. In general, ISO 11846:1995 tests resulted in a significantly lower corrosion speed, and the corrosive attack was found to be primarily along grain boundaries.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

scholarly journals SARS-CoV-2 serological assay and viral testing: a report of professional football setting

2021 ◽  
pp. postgradmedj-2021-140176
Author(s):  
Bahar Hassanmirzaei ◽  
Zohreh Haratian ◽  
Ali Ahmadzadeh Amiri ◽  
Amir Ahmadzadeh Amiri ◽  
Navid Moghadam
Keyword(s):  
Standard Test ◽  
Football Players ◽  
Professional Football ◽  
Serological Testing ◽  
Igg Antibodies ◽  
Current Standard ◽  
Serological Tests ◽  
The Mean ◽  
Viral Testing ◽  
Pcr Test

Purpose of the studyPCR is the current standard test for the diagnosis of SARS-CoV-2 infection. However, due to its limitations, serological testing is considered an alternative method for detecting SARS-CoV-2 exposure. In this study, we measured the level of SARS-CoV-2 IgM and IgG antibodies of male professional football players and compared the results with the standard PCR test to investigate the association between the two tests.Study designParticipants were male professional football players and team officials. Nasopharyngeal swabs and peripheral blood samples were collected for the PCR and serological tests, respectively. Also, previous records of COVID-19 testing and symptoms were gathered. Those with previous positive PCR tests who tested negative for the second time were considered to be recovered patients.ResultsOf the 1243 subjects, 222 (17.9%) were seropositive, while 29 (2.3%) tested positive for the SARS-CoV-2 PCR test. Sixty percent of symptomatic cases with a negative PCR were found to be seropositive. The mean level of IgM was significantly higher in PCR-positive and symptomatic subjects, whereas the recovered cases showed significantly higher levels of IgG.ConclusionOur study revealed an inconsistency of results between the two tests; therefore, although application of serological assays alone seems insufficient in diagnosing COVID-19 disease, the findings are beneficial in the comprehension and the management of the disease.

Serviceability Assessment of a Printed Finish on T-Shirts

2021 ◽  
Vol 8 (2) ◽  
pp. 48-53
Author(s):  
Reannan Riedy ◽  
Meredith McQuerry
Keyword(s):  
Abrasion Resistance ◽  
Dimensional Change ◽  
Test Methods ◽  
Standard Test ◽  
Performance Expectations ◽  
Agricultural Worker ◽  
Soil Release ◽  
And Performance ◽  
Typical Consumer ◽  
Change Material

To improve the comfort of agricultural workers, a T-shirt with a printed active cooling finish was evaluated to determine if it would meet the wash life durability and performance expectations of such an arduous application. Six shirts with a printed phase change material (PCM) finish and six shirts without (control) were washed 50 times to replicate a typical consumer wash life. Shirts were evaluated for absorbency, dimensional change, colorfastness, crocking, abrasion resistance, soil release, and smoothness retention according to AATCC and ASTM standard test methods. Testing was conducted before laundering and after 1, 5, 10, 20, 30, 35, 40, 45, and 50 consumer laundry (CL) cycles. Absorbency and dimensional change were significantly influenced by the PCM finish. Results demonstrate the appropriateness of adopting such a finish technology for agricultural worker clothing applications.

On the Construction of Analytical Cooling Curves from ASTM D6200 Data Using Multi-Variable Gradient Descent Method

2021 ◽  
Author(s):  
James Jan ◽  
D. Scott MacKenzie
Keyword(s):  
Cooling Rate ◽  
Oil Quality ◽  
Standard Test ◽  
Descent Method ◽  
Test Method ◽  
Cooling Curve ◽  
Gradient Descent Method ◽  
Mathematical Function ◽  
Current Standard ◽  
Characteristic Points

Abstract ASTM D6200 is a standard test method to evaluate cooling characteristics of quench oils. The test produces six discrete numbers representing the cooling characteristics: three temporal scales (time to cool to 600°C, 400°C, and 200°C), two cooling rates (max cooling rate and cooling rate at 300°C), and one temperature scale (at max cooling rate). One of the main purposes of ASTM D6200 is to monitor the oil quality to ensure gears are properly quenched. The current standard only includes specifications for gear quenching oil and its applications are limited to physical testing. The intent of this research is to explore the possibility of broadening the support for more quenchants and extending applications to virtual engineering. This research includes two parts. The first part is the development of a systematic method to identify the characteristic points of a cooling curve. The second part is the construction of an analytical cooling curve based on the characteristic points. The analytical cooling curve is a mathematical function of temperature versus time that can provide temperature at any given time in the quenching process. In addition, the curve is differentiable to provide the cooling rate information at any given time as well.

Development of standard test methods for unmanned and manned industrial vehicles used near humans

2013 ◽  
Author(s):  
Roger Bostelman ◽  
Richard Norcross ◽  
Joe Falco ◽  
Jeremy Marvel
Keyword(s):  
Test Methods ◽  
Standard Test

scholarly journals Derived Interaction Parameters for the TSAI-WU Tensor Polynomial Theory of Strength for Composite Materials

2001 ◽  
Author(s):  
Steven J. DeTeresa ◽  
Gregory J. Larsen
Keyword(s):  
Hydrostatic Pressure ◽  
Fiber Composite ◽  
Strength Criterion ◽  
Test Methods ◽  
Standard Test ◽  
Transverse Compression ◽  
Strength Parameters ◽  
Carbon Fiber Composite ◽  
The Stability ◽  
Stability Limits

Abstract It is shown that the two interactive strength parameters in the Tsai-Wu tensor polynomial strength criterion for fiber composites can be derived in terms of the uniaxial or non-interacting strength parameters if the composite does not fail under practical levels of hydrostatic pressure or equal transverse compression. Thus the required number of parameters is reduced from seven to five and all five of the remaining strength terms are easily determined using standard test methods. The derived interactive parameters fall within the stability limits of the theory, yet they lead to open failure surfaces in the compressive stress quadrant. The assumptions used to derive the interactive parameters were supported by measurements for the effect of hydrostatic pressure and unequal transverse compression on the behavior of a typical carbon fiber composite.

scholarly journals The synergistic effect of borax and chlorinated paraffin as flame – retardants for epoxy and unsaturated polyester resins

2008 ◽  
Vol 5 (1) ◽  
pp. 131-136
Author(s):  
Baghdad Science Journal
Keyword(s):  
Synergistic Effect ◽  
Flame Retardants ◽  
Unsaturated Polyester ◽  
Test Methods ◽  
Standard Test ◽  
Good Effect ◽  
Polyester Resins ◽  
Unsaturated Polyester Resins ◽  
Flame Retardation ◽  
Chlorinated Paraffin

In this investigation , borax (B) (additive I) and chlorinated paraffin (CP.) (additive II) ,were used as flame retardants for each of epoxy and unsaturated polyester resins in the weight ratios of 2,4,6, & 8% by preparing films of (130×130×3) mm dimensions. Also films of these resins with a mixture of [50%(B.)+50%(CP.)] (additive III) in the same weight ratios were prepared in order to study the synergistic effect of these additives on the flammability of the two resins . Three standard test methods were used to measure the flame retardation which are : 1-ASTM : D-2863 2-ASTM : D-635 3-ASTM : D-3014 The results obtained from these tests indicated that the additives (B),(CP.) and their mixture , gave a good effect as flame retardants for each epoxy and unsaturated polyester resins , but their synergistic effect was more effective than each of them alone. Finally , the compatibility between the additives and resins (which showed a clear effect on retardation) was also studied .

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