Develop Performance Specifications Research Articles

Evaluation and Development of Performance-Engineered Specifications for Monotonic Loading Cracking Performance Assessment Tests and Indicators

Abstract This study investigated the validity of various monotonic cracking performance assessment testing standards and indicators to describe the expected cracking performance in the field. A total number of 17 field test sections with known field cracking performance were selected and evaluated. Field cores were extracted from these sections, and a comprehensive laboratory testing program was carried out. The authors conducted four monotonic testing standards and calculated 11 performance indicators. The study findings showed that there was no direct correlation between the laboratory testing results of monotonic tests and indicators and the observed field cracking performance. The variable air void content and thickness of the extracted field cores are believed to influence the laboratory testing results of monotonic tests and indicators. Therefore, this study proposed an alternative approach to develop performance specifications (thresholds) for monotonic tests and indicators. The thresholds were developed indirectly using a correlation between cyclic testing and both monotonic tests and the observed field cracking performance. The results demonstrated the effectiveness and success of the proposed approach in developing performance thresholds. Pass/fail cracking performance assessment thresholds were proposed for various monotonic indicators to distinguish between asphalt mixes with good, fair, and poor cracking resistance. Besides, the study recommends the Weibull cracking resistance index, determined from the indirect tension test, as a simple performance indicator to assess mixes resistance to cracking.

Correlation of Rapid Electrochemical and Traditional Performance-Based Test Results for Assessing the Degree of Sulfate Resistance in Concrete

The aim of this study was to develop and propose classification criteria for practical assessment of concrete quality with a rapid sulfate resistance test. The rapid electrochemical sulfate resistance test based on ASTM C1202 has various advantages over the traditional performance test methods, such as short testing time, simple procedure, clear interpretation, and reasonable results. The proposed criteria were experimentally evaluated in both a series of laboratory test specimens and in specimens collected from various construction sites. The experimental results of the rapid electrochemical test and the traditional length change according to ASTM C1012 were correlated to develop performance specifications regarding ion sulfate penetration. The performance specifications proposed on the basis of this study have six levels of ion penetrability. The proposed performance specifications with rapid electrochemical test method are expected to lead to practical applications in the cement and concrete industries.

Experimental and Simulation Studies on Thermoelectric Cooler: A Performance Study Approach

The current experimental and simulation studies focus on two distinctive approaches on developing performance specifications on a typical thermoelectric cooler. The performance specifications considered for the current study involves cooling capacity, voltage, and current for different temperature ranges on hot side of the module. Simulation studies were carried out using COMSOL Multiphysics software for analyzing the coefficient of performance (COP). Thermoelectric cooler’s performance was simulated for the module’s hot side temperature ranges of about 303.15–333.15 K with a stipulated temperature interval of around 5 K. COP is evaluated at various temperature ranges (20 K, 40 K, and 60 K) over the module for each temperature prevailing on the hot side. The whole system is numerically modeled and the final attained results were correlated with the results obtained from simulation. Factors considered for modeling includes Seebeck coefficient, thermal conductivity, and resistivity variation of the Peltier elements.

Investigation of pavement raveling performance using smartphone

Raveling is one of the critical modes of failure in open graded asphalt mixtures. The Florida Department of Transportation (FDOT) Districts 4 and 6, located in southeastern Florida, have experienced a large amount of premature raveling with Open Graded Friction Course mixes (OGFC) compared to the other districts in Florida. To investigate the reason of raveling occurrence, the research team devised a data collection tool for smartphones and developed software to measure the raveling area and its location and severity in video images using smartphone GPS capability. The data used in this study were extracted from different FDOT database systems, such as the Laboratory Information Management System (LIMS) and the Electronic Data Management System (EDMS), as well as from the National Oceanic and Atmospheric Administration (NOAA).Ten projects were surveyed by the research team, and numerical raveling statistics were developed and compared with qualitative raveling ratings provided by FDOT. Good correlation was found between the two methods. The comparison was used to establish thresholds of good performance. Such thresholds can be used to develop performance specifications or warranty benchmarks.The relative effects of mix design, construction, and environmental factors were also studied. A project level of analysis was conducted. Several hypotheses were evaluated to determine the cause of premature raveling. Data analysis results indicate significant correlations between raveling and ambient temperature, mix temperature, mix spread rate, and gradation. In light of this study, recommendations were made to enhance the longevity of the OGFC mixtures.

Risks associated with performance specifications in highway infrastructure procurement

Proper identification, allocation, and pricing of risks are critical to effective procurement and project delivery, particularly when contracts specify the intended performance instead of how the work is to be performed. This paper presents an overview of the sources of project risks when performance specifications are used for highway infrastructure procurement. The findings are based on a comprehensive literature review and interviews with subject-matter experts involved in developing performance specifications for highway infrastructure. The authors conclude that wider use of performance specifications in U.S. highway infrastructure construction requires a fundamental reassessment of risk allocation and pricing. Highway agencies and the contractors need to realign their respective organizational capabilities with the goal of using performance specifications as a facilitator of innovation, a goal that remains elusive after decades of applied research.

Risks associated with performance specifications in highway infrastructure procurement

Proper identification, allocation, and pricing of risks are critical to effective procurement and project delivery, particularly when contracts specify the intended performance instead of how the work is to be performed. This paper presents an overview of the sources of project risks when performance specifications are used for highway infrastructure procurement. The findings are based on a comprehensive literature review and interviews with subject-matter experts involved in developing performance specifications for highway infrastructure. The authors conclude that wider use of performance specifications in U.S. highway infrastructure construction requires a fundamental reassessment of risk allocation and pricing. Highway agencies and the contractors need to realign their respective organizational capabilities with the goal of using performance specifications as a facilitator of innovation, a goal that remains elusive after decades of applied research.

Hematology Analyzers and Body Fluid Analysis

To the Editor Although the article by De Smet et al1 is an interesting evaluation of hematology instrument performance with body fluids, such instruments were designed for, and cleared by regulatory bodies only for, blood samples. There are significant scientific errors or weaknesses in several of the approaches taken to develop performance specifications for cytopenic body fluid samples, as briefly discussed herein. The authors describe their approach to “background concentration limits,” which simply applies a +2 SD value to the mean of 20 instrument cycles (presumably air aspirations, although not stated). As noted in the EP-17 consensus document from the Clinical and Laboratory Standards Institute,2 this common practice lacks appropriate statistical rigor and leads to falsely low values. EP-17 provides a more …

A digital circuit performance analysis for tandem burst-error links in an ISDN environment

Tandem links with burst errors are analyzed using alternative renewal processes in continuous time. As in the well-known Gilbert model it is assumed that individual links can be either in the good state in which the bit error rate is low, or in the bad (bursty) state in which the bit error rate is momentarily high. For end-to-end digital connection utilizing M links in tandem, three performance measures are derived: average bit error rate, the percentage of available time and the percentage of error-free seconds. These measures are currently being proposed by CCITT for developing performance specifications of ISDN connections.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Performance Analysis of Tandem Burst-Error Links with Applications to ISDN

In this paper, tandem links with burst errors are analyzed using the Gilbert model for individual links. The results, apart from being of general interest, are of particular relevance to the Integrated Services Digital Networks (ISDN) for which the International Telegraph and Telephone Consultative Committee (CCITT) is currently developing performance specifications based on hypothetical reference connections (HRX's), i.e., composite channels consisting of several tandem reference circuits. The average error rate, the error gap distribution, its mean, and a tight upper bound on its standard deviation are analytically derived for the composite channel (equivalent to an HRX) with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</tex> tandem links (circuits). These statistics are then related to the performance measures proposed for ISDN. Some numerical results are presented to highlight the large differences in the estimated performance with a burst-error model approach and with an independent-error approach (having identical average error probabilities).