scholarly journals Additional Criteria for Playground Impact Attenuating Sand

2021 ◽  
Vol 11 (19) ◽  
pp. 8805
Author(s):  
David Eager ◽  
Chris Chapman ◽  
Yujie Qi ◽  
Karlos Ishac ◽  
Md Imam Hossain
Keyword(s):  
Particle Shape ◽  
Test Methods ◽  
Test Method ◽  
Wood Fibre ◽  
Long Bone ◽  
Accelerated Ageing ◽  
Sand Particle ◽  
Severity Of Injury ◽  
Fibre Products ◽  
The Impact

Falls within children’s playgrounds result in long bone and serious injuries. To lower the likelihood and severity of injury, impact attenuating surfaces (IAS) are installed within the impact area (fall zone). There are three primary IAS materials used, namely: granulated rubber products, wood fibre products, and sand. There is a deficiency with existing IAS test methods in that they do not take account of sand degradation over time. When children use the playground, sand degradation can occur when sand produces fines and smaller particles with low sphericity and angular which fill the voids between the sand particles. These fines and smaller particles tend to bind the sand and lower its impact attenuating performance. This paper proposes an additional IAS test to eliminate sands that degrade above an established threshold rate after installation due to normal usage. IAS degradation properties of fifteen IAS sands were tested including sand particle shape, sand particle distribution, percentage fines and sand particle degradation. This accelerated ageing test method is applicable only to sands and not rubber or wood fibre IAS products. The best IAS sands were sourced from quarries located on rivers that had eroded volcanic outcrops. These sands were shown to degrade the least and had little to no fines, and their particle shape was rounded to well-rounded. The most reliable source for good quality IAS sands on these rivers was on specific bends. The sand mined at these locations consistently had a tight particle size distribution.

Estimation of Depth of Concrete Column Members Using Impact Echo Method

2014 ◽  
Vol 605 ◽  
pp. 194-197
Author(s):  
Seung Hun Kim ◽  
Seong Uk Hong ◽  
Yong Taeg Lee ◽  
Seung Ho Lee
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Concrete Column ◽  
Ground Field ◽  
Design Strength ◽  
Impact Echo ◽  
Destructive Test ◽  
The Impact ◽  
Non Destructive ◽  
Impact Echo Method

In order to maintain the existing concrete structures in a safe and usable state, an overall maintenance management is necessary regarding structure aging from quality management of new construction. Thus, non-destructive testing is needed to estimate the structure damage, defect, or proper construction without damaging the structure. In U.S., there is a standard for non-destructive test (ACI 228.2R-98), and also in Japan, the non-destructive test method and compressive strength estimation manual was prepared by the Architectural Institute of Japan in 1983, and there are active researches in the ground field, but it lacks verification in architecture field. Thus, in this study, a technique that can estimate the depth of concrete column member using the Impact Echo method which is one of the non-destructive test methods shall be reviewed and evaluated for applicability to the architecture field. The specimen was mixed with design strength of 30MPa. The equipment used in testing is Freedom Date Pc Platform Win.TFS 2.5.2 by company Olson of U.S., and the experiment involved leveling the top surface of the concrete member, installing the equipment and applying impact 9 times, and taking the average of the reverberation values obtained. The estimated average depth of concrete column member using Impact Echo method was 304mm for IEC-300, 398mm for IEC-400, and 484mm for IEC-500, and the relative error rate compared to the actual size was 1%~3%. Through this study, the applicability of estimation of depth in concrete column members using impact echo method could be confirmed.

The modern methods of pin-type bearing test of metallic materials

2019 ◽  
Vol 85 (7) ◽  
pp. 41-49
Author(s):  
Yaroslava V. Sulimina ◽  
Nikolay O. Yakovlev ◽  
Vladimir S. Erasov ◽  
Aleksey Yu. Ampilogov ◽  
Andrey N. Polyakov ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Test Procedure ◽  
Test Methods ◽  
Test Method ◽  
Strength Characteristics ◽  
Metallic Materials ◽  
Bearing Strength ◽  
Bearing Stress ◽  
The Impact

The special features of various bearing deformation measurements for pin-type bearing tests of metallic materials are considered along with their impact on the magnitude of the «bearing elastic modulus» and bearing stress. These bearing test methods are present in ASTM and various institutional standards, though no state standard (GOST, GOST R) is currently available for bearing test method of metallic materials. Analysis of additional deformations which arise in determining the degree of hole bearing deformation is carried out. A set of sources of additional deformations is shown to be characteristic for each test procedure and is attributed to the design features of the device, the site and a way of mounting the extensometer. Additional deformations can be both tensile and compressive. It is shown that the impact of additional deformations on the «bearing elastic modulus» is limited to 14% for different procedures. No difference between the methods is revealed with regard to determination of the strength characteristics. At the same time the dispersion decreases with increase in plastic deformation and for bearing deformation about 4% the variation coefficient for all methods is no more than 1%. Advantages and shortcomings of the bearing test methods which affect the reproducibility of the results are considered. The effect of the specimen geometry on the bearing characteristics is considered. It is shown that increase both in the distance from the edge of the bearing specimen to the center of the hole for 1163T, VT6ch, 30KhGSA alloys and residual bearing deformation up to 6%, increase bearing strength characteristics.

scholarly journals What can gaze behaviors, neuroimaging data, and test scores tell us about test method effects and cognitive load in listening assessments?

2021 ◽  
pp. 026553222110268
Author(s):  
Vahid Aryadoust ◽  
Stacy Foo ◽  
Li Ying Ng
Keyword(s):  
Eye Tracking ◽  
Cognitive Load ◽  
Test Scores ◽  
Test Validity ◽  
Test Methods ◽  
Load Test ◽  
Test Method ◽  
Functional Near Infrared Spectroscopy ◽  
Listening Test ◽  
The Impact

The aim of this study was to investigate how test methods affect listening test takers’ performance and cognitive load. Test methods were defined and operationalized as while-listening performance (WLP) and post-listening performance (PLP) formats. To achieve the goal of the study, we examined test takers’ ( N = 80) brain activity patterns (measured by functional near-infrared spectroscopy (fNIRS)), gaze behaviors (measured by eye-tracking), and listening performance (measured by test scores) across the two test methods. We found that the test takers displayed lower activity levels across brain regions supporting comprehension during the WLP tests relative to the PLP tests. Additionally, the gaze behavioral patterns exhibited during the WLP tests suggested that the test takers adopted keyword matching and “shallow listening.” Together, the neuroimaging and gaze behavioral data indicated that the WLP tests imposed a lower cognitive load on the test takers than the PLP tests. However, the test takers performed better with higher test scores for one of two WLP tests compared with the PLP tests. By incorporating eye-tracking and neuroimaging in this exploration, this study has advanced the current knowledge on cognitive load and the impact imposed by different listening test methods. To advance our knowledge of test validity, other researchers could adopt our research protocol and focus on extending the test method framework used in this study.

Model Tests for Evaluating the Impact of Low Viscosity Tailor-Made Biofuels on Tribological Contacts in Injection Pumps

2013 ◽  
Author(s):  
Stefan Heitzig ◽  
Alexander Weinebeck ◽  
Hubertus Murrenhoff
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
Research Approach ◽  
Low Viscosity ◽  
Injection Pump ◽  
The Impact ◽  
Fuel Lubricity

In the scope of the cluster of excellence “Tailor-made Fuels from Biomass” new biofuels are developed within an interdisciplinary research approach at RWTH Aachen University. To ensure a safe and reliable functioning of the new fuels in combination with state of the art fuel injection equipment, every fuel has to fulfil requirements regarding its tribological performance, which depends on characteristics like dynamic viscosity and fuel lubricity. Hence, one focus of the cluster lies on the tribological characteristics of the fuel candidates. Biofuel candidates which have been investigated so far and which are suitable for the use in self-ignition engines as surrogates for fossil diesel fuel tend to have lower viscosities and show varying lubrication behaviour, compared to diesel. As a standard test method for diesel fuel lubricity the HFRR test is well established. Nevertheless, relying on the established diesel-pass/fail criterion, which is defined in several norms, is disputable, since the investigated biofuels differ strongly from modern diesel fuels. To identify the relevant fuel properties and to gain a more detailed understanding of the wear and friction processes within the critical contacts, results of different tribological test methods, including the HFRR test and a disc-on-disc tribometer, are presented, compared and discussed in this paper. In order to estimate the validity of the established HFRR pass/fail criterion for low viscosity biofuels the experimental results are compared to simulation outcomes of elasto-hydrodynamic simulations of the main tribological contacts in a standard common rail injection pump.

scholarly journals Removing Critical Gaps in Chemical Test Methods by Developing New Assays for the Identification of Thyroid Hormone System-Disrupting Chemicals—The ATHENA Project

2020 ◽  
Vol 21 (9) ◽  
pp. 3123 ◽  
Author(s):  
Andreas Kortenkamp ◽  
Marta Axelstad ◽  
Asma H. Baig ◽  
Åke Bergman ◽  
Carl-Gustaf Bornehag ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Test Methods ◽  
Test Method ◽  
In Vitro Assays ◽  
Hormone Action ◽  
Chemical Test ◽  
Thyroid Hormone Action ◽  
The Impact ◽  
Hormone System

The test methods that currently exist for the identification of thyroid hormone system-disrupting chemicals are woefully inadequate. There are currently no internationally validated in vitro assays, and test methods that can capture the consequences of diminished or enhanced thyroid hormone action on the developing brain are missing entirely. These gaps put the public at risk and risk assessors in a difficult position. Decisions about the status of chemicals as thyroid hormone system disruptors currently are based on inadequate toxicity data. The ATHENA project (Assays for the identification of Thyroid Hormone axis-disrupting chemicals: Elaborating Novel Assessment strategies) has been conceived to address these gaps. The project will develop new test methods for the disruption of thyroid hormone transport across biological barriers such as the blood–brain and blood–placenta barriers. It will also devise methods for the disruption of the downstream effects on the brain. ATHENA will deliver a testing strategy based on those elements of the thyroid hormone system that, when disrupted, could have the greatest impact on diminished or enhanced thyroid hormone action and therefore should be targeted through effective testing. To further enhance the impact of the ATHENA test method developments, the project will develop concepts for better international collaboration and development in the area of thyroid hormone system disruptor identification and regulation.

The Influence of Turbulence (or Hydrodynamic Effects) on Strontium Sulphate Scale Formation and Inhibitor Performance

2014 ◽  
Author(s):  
Clare Johnston ◽  
Louise Sutherland
Keyword(s):  
Barium Sulphate ◽  
Test Methods ◽  
Standard Test ◽  
Field Application ◽  
Scale Formation ◽  
Test Method ◽  
Scale Inhibitor ◽  
Modified Method ◽  
Bottle Test ◽  
The Impact

Abstract Inorganic scale (carbonate, sulphate and sulphides) formation can be predicted from thermodynamic models and over recent years better kinetic data has improved the prediction of such scales in field conditions. However these models have not been able to predict the observed deposition where flow disturbances occur, such as at chokes, tubing joints, gas lift valves and safety valves. This can lead to unexpected failures of critical equipment such as downhole safety valves (DHSV’s), and operational issues such as failure to access the well for coiled tubing operations due to tubing restrictions. In recent years it has been recognised that the turbulence found at these locations increases the likelihood of scale formation and experiments have been able to demonstrate that increased turbulence also impacts the minimum scale inhibitor concentration required to prevent scale. One of the industry standard test methods used to screen inhibitors for sulphate scale inhibition is the static bottle test. In this paper the ‘static’ bottle test method is modified to investigate the effects of increasing levels of turbulence on the formation of strontium sulphate scale at a fixed brine composition. Using this modified method it has been possible to demonstrate the impact of varying turbulence on the performance of two common generic types of scale inhibitor (phosphonate and vinyl sulphonate co-polymer). Data on the mass of scale formed, scale morphology using SEM imaging and inhibitor efficiency will be linked to degree of turbulence and scale inhibitor functionality (nucleation inhibition vs. crystal growth retardation). This study builds on the previously published10 findings for barium sulphate which showed phosphonates were less affected by turbulent conditions by carrying out similar tests on strontium sulphate. A clear mechanistic conclusion can now be drawn for sulphate scale formation and inhibition under increasingly turbulent conditions. The findings from this study have a significant impact on the methods of screening scale inhibitors for field application that should be utilised and development of suitable inhibitors that perform better under higher shear conditions.

Cause Analysis of Sand Density and Engineering Evaluation

2014 ◽  
Vol 638-640 ◽  
pp. 416-421
Author(s):  
Xiang Guo Kong
Keyword(s):  
Particle Shape ◽  
Test Methods ◽  
Engineering Properties ◽  
Sand Particle ◽  
Theoretical Knowledge ◽  
Confined Water ◽  
Cause Analysis ◽  
Test Error ◽  
Abnormal Phenomenon ◽  
Shape And Size

The density of the sand is important factor for its engineering properties, There are many methods to evaluate the sand density, just the results may be differences, usually means, this is the test error of the different test methods. In fact, the reasons of the sand formation and buried conditions, sand particle shape and size, sand gradation, groundwater etc. are also the important factors for its engineering properties, but these factors are often ignored. Bearing pressure of confined water will change the distribution of the effective weight stress in soil and the abnormal phenomenon of sand density will appear. In the project, the cause analysis of sand density require attention. According to theoretical knowledge, to identify applicable conditions of the various evaluation methods and their advantages and shortcomings.

An evaluation of ECT sample height for small flute board grades and Box Manufacturer’s Certification compliance

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK
Keyword(s):  
Compressive Strength ◽  
Compressive Load ◽  
Test Sample ◽  
Test Methods ◽  
Test Method ◽  
Initial Development ◽  
Sample Height ◽  
Relationship Of ◽  
The Relationship ◽  
Corrugated Fiberboard

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.

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