scholarly journals Test Methods For Evaluating The Oxidization Potential Of Sulphide –Bearing Aggregates And Its Effects On Concrete Durability

2021 ◽  
Author(s):  
Bassili Guirguis
Keyword(s):  
Ferric Hydroxide ◽  
Silica Content ◽  
Test Methods ◽  
Test Method ◽  
Concrete Durability ◽  
Oxidizing Agent ◽  
Wide Range ◽  
High Silica ◽  
Mortar Bar ◽  
Development And Validation

This research project focuses on the development and validation of test methods to evaluate the potential oxidation of sulphide-bearing aggregates, which can cause severe damage when used in concrete. The mechanism of damage is believed to consist of two parts: (a) the oxidation of sulphide minerals, which results in the formation of ferric hydroxide, and (b) the formation of sulphuric acid, which reacts with calcium hydroxide in concrete leading to an internal sulphate attack. Both parts produce a volume increase, damaging the concrete. A simple, quick and economical test method was developed and used to test thirty-one aggregates with different sulphur content. This test involves soaking the aggregate in an oxidizing agent at room temperature, washing the aggregate on a specific sieve, and drying it at 80°C. The soaking and drying cycle is repeated and the disintegration of the aggregates is measured as % mass loss. The composition of the oxidizing solution was evaluated, and the assessment of the aggregate was related to the presence of iron and sulphur ions in the solution after the test. The aggregate oxidation test developed here is anticipated to be adopted as a screening test method by North American standards due to its simplicity and applicability to a wide range of aggregates. The expansion of recently developed mortar bar samples containing a limited number of aggregates proves that the test can show expansion in aggregates with sulphide as well as high silica content; however, the high-silica aggregate did not show significant expansion in the second stage of the test, unlike the sulphide-bearing aggregates. The test was examined for its ability to evaluate the effects of supplementary cementing materials (SCM`s) on mitigating the damage in mortars containing sulphide-bearing aggregates. The results revealed that extended exposure to the oxidizing agent caused damage in the bar due to reasons other than the oxidation of sulphide phases when SCM with high reactive alumina is used. In addition, the results revealed that silica fume and low-calcium fly ash were effective in mitigating the damage, however, the efficacy of SCM`s is mainly linked to their ability to reduce the penetration of oxidizing agents into the mortar bars. These results need to be validated using field investigations. Concrete samples were tested under different conditions in an attempt to replicate the damage mechanisms in concrete samples under lab conditions. Some of the testing regimes showed promising results and are recommended for future studies.

scholarly journals Test Methods For Evaluating The Oxidization Potential Of Sulphide –Bearing Aggregates And Its Effects On Concrete Durability

2021 ◽  
Author(s):  
Bassili Guirguis
Keyword(s):  
Ferric Hydroxide ◽  
Silica Content ◽  
Test Methods ◽  
Test Method ◽  
Concrete Durability ◽  
Oxidizing Agent ◽  
Wide Range ◽  
High Silica ◽  
Mortar Bar ◽  
Development And Validation

This research project focuses on the development and validation of test methods to evaluate the potential oxidation of sulphide-bearing aggregates, which can cause severe damage when used in concrete. The mechanism of damage is believed to consist of two parts: (a) the oxidation of sulphide minerals, which results in the formation of ferric hydroxide, and (b) the formation of sulphuric acid, which reacts with calcium hydroxide in concrete leading to an internal sulphate attack. Both parts produce a volume increase, damaging the concrete. A simple, quick and economical test method was developed and used to test thirty-one aggregates with different sulphur content. This test involves soaking the aggregate in an oxidizing agent at room temperature, washing the aggregate on a specific sieve, and drying it at 80°C. The soaking and drying cycle is repeated and the disintegration of the aggregates is measured as % mass loss. The composition of the oxidizing solution was evaluated, and the assessment of the aggregate was related to the presence of iron and sulphur ions in the solution after the test. The aggregate oxidation test developed here is anticipated to be adopted as a screening test method by North American standards due to its simplicity and applicability to a wide range of aggregates. The expansion of recently developed mortar bar samples containing a limited number of aggregates proves that the test can show expansion in aggregates with sulphide as well as high silica content; however, the high-silica aggregate did not show significant expansion in the second stage of the test, unlike the sulphide-bearing aggregates. The test was examined for its ability to evaluate the effects of supplementary cementing materials (SCM`s) on mitigating the damage in mortars containing sulphide-bearing aggregates. The results revealed that extended exposure to the oxidizing agent caused damage in the bar due to reasons other than the oxidation of sulphide phases when SCM with high reactive alumina is used. In addition, the results revealed that silica fume and low-calcium fly ash were effective in mitigating the damage, however, the efficacy of SCM`s is mainly linked to their ability to reduce the penetration of oxidizing agents into the mortar bars. These results need to be validated using field investigations. Concrete samples were tested under different conditions in an attempt to replicate the damage mechanisms in concrete samples under lab conditions. Some of the testing regimes showed promising results and are recommended for future studies.

scholarly journals Advancing Measurement Science to Assess Monitoring, Diagnostics, and Prognostics for Manufacturing Robotics

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
Guixiu Qiao ◽  
Brian A. Weiss
Keyword(s):  
Method Development ◽  
Performance Metrics ◽  
Health Management ◽  
Test Methods ◽  
Test Method ◽  
Verification And Validation ◽  
Positional Accuracy ◽  
Measurement Science ◽  
Wide Range ◽  
Barriers And Challenges

Unexpected equipment downtime is a ‘pain point’ for manufacturers, especially in that this event usually translates to financial losses. To minimize this pain point, manufacturers are developing new health monitoring, diagnostic, prognostic, and maintenance (collectively known as prognostics and health management (PHM)) techniques to advance the state-of-the-art in their maintenance strategies. The manufacturing community has a wide-range of needs with respect to the advancement and integration of PHM technologies to enhance manufacturing robotic system capabilities. Numerous researchers, including personnel from the National Institute of Standards and Technology (NIST), have identified a broad landscape of barriers and challenges to advancing PHM technologies. One such challenge is the verification and validation of PHM technology through the development of performance metrics, test methods, reference datasets, and supporting tools. Besides documenting and presenting the research landscape, NIST personnel are actively researching PHM for robotics to promote the development of innovative sensing technology and prognostic decision algorithms and to produce a positional accuracy test method that emphasizes the identification of static and dynamic positional accuracy. The test method development will provide manufacturers with a methodology that will allow them to quickly assess the positional health of their robot systems along with supporting the verification and validation of PHM techniques for the robot system.

EFFECT OF SOIL ORDER, pH, TEXTURE AND ORGANIC MATTER ON THE CORRELATION BETWEEN PHOSPHORUS IN ALFALFA AND SOIL-TEST VALUES

1967 ◽  
Vol 47 (3) ◽  
pp. 157-161 ◽  
Author(s):  
M. K. John ◽  
A. L. van Ryswyk ◽  
J. L. Mason
Keyword(s):  
Soil Ph ◽  
Soil Phosphorus ◽  
Test Methods ◽  
Test Method ◽  
Available Phosphorus ◽  
Soil Test ◽  
Tissue Samples ◽  
Podzolic Soils ◽  
Wide Range ◽  
The Relationship

Soil and tissue samples were collected from 192 alfalfa fields representing a wide variety of cultivated soils in British Columbia. The phosphorus content of the alfalfa was correlated with the amounts of available P extracted by eight soil-test methods. The Olsen method, Bray's P1 method, and a modification of Bray's P1 method showed high correlation with plant phosphorus over a wide range of soils; the other five methods showed lower correlation. The relationship observed between soil phosphorus and plant phosphorus differed with soil pH and soil order for the various available-phosphorus methods used. None of the methods gave significant correlations with the Solonetzic and Podzolic soils. Multiple correlation studies indicated that soil pH and texture were required to explain the contribution of available phosphorus in soil, as measured by any soil-test method, to phosphorus in alfalfa.

scholarly journals Track loading on Russian Railways under modern maintenance conditions

2019 ◽  
Vol 135 ◽  
pp. 02002
Author(s):  
Victor Kochergin ◽  
Igor Maksimov ◽  
Victor Pevzner ◽  
Evgeniya Polunina
Keyword(s):  
Point Contact ◽  
Field Tests ◽  
Test Methods ◽  
Test Method ◽  
Rolling Stock ◽  
Bench Test ◽  
Contact Loading ◽  
Static Tests ◽  
Bench Tests ◽  
Wide Range

Rail fasteners loading and its influence on the track deformability under modern maintenance conditions with increased cars axle loads is observed. The difference between oneand two-point wheelrail contact loading scheme is shown. The authors present the analysis of domestic and foreign methods of pads bench tests and show the necessity of carrying out tests imitating real (two-point contact) loading of pads. The bench test method for researching fastener loading and pad strain characteristics in a wide range of vertical and lateral loads under two-point contact scheme based on a number of field tests is presented. The results of static tests and following dynamic ones with cycling loading, which were carried out on a two-sleepers bench, are observed. Bench tests carried out by VNIIZHT and the analysis of the cyclic test methods showed the importance of fasteners tests with a real loading simulation making it possible to explain the causes of track gauge widening and decrease of track inclination, which considerably influences track stability and wear of the track and rolling stock.

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.

scholarly journals Environmental Flow Assessment Considering Inter- and Intra-Annual Streamflow Variability under the Context of Non-Stationarity

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1737 ◽  
Author(s):  
Kang Ren ◽  
Shengzhi Huang ◽  
Qiang Huang ◽  
Hao Wang ◽  
Guoyong Leng
Keyword(s):  
Kendall Test ◽  
Environmental Flow ◽  
Mean Value ◽  
Test Method ◽  
Stationary Condition ◽  
Annual Streamflow ◽  
Riverine Ecosystems ◽  
Study Results ◽  
Wide Range ◽  
Streamflow Variability

A key challenge to environmental flow assessment in many rivers is to evaluate how much of the discharge flow should be retained in the river in order to maintain the integrity and valued features of riverine ecosystems. With the increasing impact of climate change and human activities on riverine ecosystems, the natural flow regime paradigm in many rivers has become non-stationary conditions, which is a new challenge to the assessment of environmental flow. This study presents a useful framework to (1) detect change points in runoff time series using two statistical methods (Mann-Kendall test method and heuristic segmentation method), (2) adjust data of the changed period against the original flow series into a stationary condition using a procedure of reconstruction; and (3) incorporate inter- and intra-annual streamflow variability with adjusted streamflow to evaluate environmental flow. The Jialing to Han inter-basin water transfer project was selected as the case study. Results indicate that a change point of 1994 was identified, revealing that the stationarity of annual streamflow series is invalid. The variations of reconstructed streamflow series are roughly consistent with original streamflow series, especially in the maximum/minimum values and rise/fall rates, but the mean value of reconstructed streamflow series is increased. The reconstructed streamflow series would further serve to eliminate the non-stationary of original streamflow, and incorporating the inter- and intra-annual variability would upgrade the ecosystem fitness. Selecting different criteria for the conservation of riverine ecosystems can have significantly different consequences, and we should not focus on the protection of specific objectives that will inevitably affect other aspects. This study provides a useful framework for environmental flow assessment and can be applied to a wide range of instream flow management approaches to protect the riverine ecosystem.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

scholarly journals Development and Validation of 2-Azaspiro [4,5] Decan-3-One (Impurity A) in Gabapentin Determination Method Using qNMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1656
Author(s):  
Nataliya E. Kuz’mina ◽  
Sergey V. Moiseev ◽  
Mikhail D. Khorolskiy ◽  
Anna I. Lutceva
Keyword(s):  
Test Procedure ◽  
Active Pharmaceutical Ingredient ◽  
Test Methods ◽  
Intermediate Precision ◽  
Coefficients Of Variation ◽  
Validation Parameters ◽  
Limit Of Quantitation ◽  
Student’S T ◽  
Development And Validation ◽  
Student’S T Test

The authors developed a 1H qNMR test procedure for identification and quantification of impurity A present in gabapentin active pharmaceutical ingredient (API) and gabapentin products. The validation studies helped to determine the limit of quantitation and assess linearity, accuracy, repeatability, intermediate precision, specificity, and robustness of the procedure. Spike-and-recovery assays were used to calculate standard deviations, coefficients of variation, confidence intervals, bias, Fisher’s F test, and Student’s t-test for assay results. The obtained statistical values satisfy the acceptance criteria for the validation parameters. The authors compared the results of impurity A quantification in gabapentin APIs and capsules by using the 1H qNMR and HPLC test methods.

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