Accuracy profile validation of a new analytical method for propane measurement using headspace-gas chromatography-mass spectrometry

Propane can be responsible for several types of lethal intoxication and explosions. Quantifying it would be very helpful to determine in some cases the cause of death. Some gas chromatography-mass spectrometry (GC-MS) methods of propane measurements do already exist. The main drawback of these GC-MS methods described in the literature is the absence of a specific propane internal standard necessary for accurate quantitative analysis. The main outcome of the following study was to provide an innovative Headspace-GC-MS method (HS-GC-MS) applicable to the routine determination of propane concentration in forensic toxicology laboratories. To date, no stable isotope of propane is commercially available. The development of an in situ generation of standards is thus presented. An internal-labeled standard gas (C3DH7) is generated in situ by the stoichiometric formation of propane by the reaction of deuterated water (D2O) with Grignard reagent propylmagnesium chloride (C3H7MgCl). The method aims to use this internal standard to quantify propane concentrations and, therefore, to obtain precise measurements. Consequently, a complete validation with an accuracy profile according to two different guidelines, the French Society of Pharmaceutical Sciences and Techniques (SFSTP) and the Gesellschaft für toxikologische und Forensische Chemie (GTFCh), is presented.

Calibration and Reliability of a Nuclear Asphalt Content Gauge, MLR-87-02, 1987

Based on results of an evaluation performed during the winter of 1985-86, six Troxler 3241-B Asphalt Content Gauges were purchased for District use in monitoring project asphalt contents. Use of these gauges will help reduce the need for chemical based extractions. Effective use of the gauges depends on the accurate preparation and transfer of project mix calibrations from the Central Lab to the Districts. The objective of this project was to evaluate the precision and accuracy of a gauge in determining asphalt contents and to develop a mix calibration transfer procedure for implementation during the 1987 construction. The first part of the study was accomplished by preparing mix calibrations in the Central Lab gauge and taking multiple measurements of a sample with known asphalt content. The second part was accomplished by preparing transfer pans, obtaining count data on the pans using each gauge, and transferring calibrations from one gauge to another through the use of calibration transfer equations. The transferred calibrations were tested by measuring samples with a known asphalt content. The study established that the Troxler 3241-B Asphalt Content Gauge yields results of acceptable accuracy and precision as evidenced by a standard deviation of 0.04% asphalt content on multiple measurements of the same sample. The calibration transfer procedure proved feasible and resulted in the calibration transfer portion of Materials I.M. 335 - Method of Test For Determining the Asphalt Content of Bituminous Mixtures by the Nuclear Method.

Implementing the Mechanistic-Empirical Pavement Design Guide: Implementation Plan, TR-509, 2005

The current 1993 American Association of State Highway and Transportation Officials (AASHTO) Pavement Design Guide is based on the empirical interpretation of the results of the 1960 AASHTO Road Test. With the release of the new Mechanistic-Empirical (M-E) Pavement Design Guide, pavement design has taken a "quantum" leap forward. In order to effectively and efficiently transition to the M-E Pavement Design Guide, state DOTs need a detailed implementation and training strategy. This document is a plan for the M-E Pavement Design Guide to be implemented in Iowa.

The Deleterious Chemical Effects of Concentrated Deicing Solutions on Portland Cement Concrete, TR-480, Implementation Guide, 2008

This research project investigated the effects of concentrated brines of magnesium chloride, calcium chloride, sodium chloride, and calcium magnesium acetate on portland cement concrete. Although known to be effective at deicing and anti-icing, the deleterious effects these chemicals may have on concrete have not been well documented. As a result of this research, it was determined that there is significant evidence that magnesium chloride and calcium chloride chemically interact with hardened portland cement paste in concrete resulting in expansive cracking, increased permeability, and a significant loss in compressive strength. Although the same effects were not seen with sodium chloride brines, it was shown that sodium chloride brines have the highest rate of ingress into hardened concrete. This latter fact is significant with respect to corrosion of embedded steel. The mechanism for attack of hardened cement paste varies with deicer chemical but in general, a chemical reaction between chlorides and cement hydration products results in the dissolution of the hardened cement paste and formation of oxychloride phases, which are expansive. The chemical attack of the hardened cement paste is significantly reduced if supplementary cementitious materials are included in the concrete mixture. Both coal fly ash and ground granulated blast furnace slag were found to be effective at mitigating the chemical attack caused by the deicers tested. In the tests performed, ground granulated blast furnace slag performed better as a mitigation strategy as compared to coal fly ash. Additionally, siloxane and silane sealants were effective at slowing the ingress of deicing chemicals into the concrete and thereby reducing the observed distress. In general, the siloxane sealant appeared to be more effective than the silane, but both were effective and should be considered as a maintenance strategy.

Review of Inconsistencies Between SUDAS and Iowa DOT Specifications Phase II: Implementation of Recommendations into SUDAS Specifications, TR-565, 2008

The current version of the SUDAS Specifications will be revised to accommodate the DOT’s utilization of SUDAS. The revisions to the SUDAS Specifications will be based upon the recommendations from Phase 1. In some instances, the recommendations will require reorganization of portions of the SUDAS Specifications. Upon incorporation of the Phase 1 recommendations, each applicable Division of the SUDAS Specifications will be updated into the active-imperative style, utilizing the 3- part specification format currently utilized by SUDAS.

Review of Inconsistencies Between SUDAS and Iowa DOT Specifications Phase II: Implementation of Recommendations into SUDAS Specifications, TR-565, Synopsis, 2008

The current version of the SUDAS Specifications will be revised to accommodate the DOT’s utilization of SUDAS. The revisions to the SUDAS Specifications will be based upon the recommendations from Phase 1. In some instances, the recommendations will require reorganization of portions of the SUDAS Specifications. Upon incorporation of the Phase 1 recommendations, each applicable Division of the SUDAS Specifications will be updated into the active-imperative style, utilizing the 3- part specification format currently utilized by SUDAS.

Implementation of a Pilot Continuous Monitoring System: Iowa Falls Arch Bridge, HR-1088, 2015

The goal of this work was to move structural health monitoring (SHM) one step closer to being ready for mainstream use by the Iowa Department of Transportation (DOT) Office of Bridges and Structures. To meet this goal, the objective of this project was to implement a pilot multi-sensor continuous monitoring system on the Iowa Falls Arch Bridge such that autonomous data analysis, storage, and retrieval can be demonstrated. The challenge with this work was to develop the open channels for communication, coordination, and cooperation of various Iowa DOT offices that could make use of the data. In a way, the end product was to be something akin to a control system that would allow for real-time evaluation of the operational condition of a monitored bridge. Development and finalization of general hardware and software components for a bridge SHM system were investigated and completed. This development and finalization was framed around the demonstration installation on the Iowa Falls Arch Bridge. The hardware system focused on using off-the-shelf sensors that could be read in either “fast” or “slow” modes depending on the desired monitoring metric. As hoped, the installed system operated with very few problems. In terms of communications—in part due to the anticipated installation on the I-74 bridge over the Mississippi River—a hardline digital subscriber line (DSL) internet connection and grid power were used. During operation, this system would transmit data to a central server location where the data would be processed and then archived for future retrieval and use. The pilot monitoring system was developed for general performance evaluation purposes (construction, structural, environmental, etc.) such that it could be easily adapted to the Iowa DOT’s bridges and other monitoring needs. The system was developed allowing easy access to near real-time data in a format usable to Iowa DOT engineers.

Review of Inconsistencies Between SUDAS and Iowa DOT Specifications Phase III: Continued Implementation of Recommendations into SUDAS Specifications, TR-607, 2010

The objective of the Phase 3 project was to re-write the identified sections of the SUDAS specifications into the imperative mood, consistent with the format utilized during the Phase 2 project and other work completed by SUDAS staff. Figures for the identified sections were updated to match the new SUDAS format, similar to the Iowa DOT Standard Road Plans. While the Iowa DOT does not intend to incorporate all of the following sections into their specification book, consistency with the Iowa DOT specifications was strived for wherever possible. Maintaining consistency between the specifications simplifies design, bidding, and construction.

Implementation Manual — 3D Engineered Models for Highway Construction: The Iowa Experience; RB33-014, 2015

3D engineered modeling is a relatively new and developing technology that can provide numerous benefits to owners, engineers, contractors, and the general public. This manual is for highway agencies that are considering or are in the process of switching from 2D plan sets to 3D engineered models in their highway construction projects. It will discuss some of the benefits, applications, limitations, and implementation considerations for 3D engineered models used for survey, design, and construction. Note that is not intended to cover all eventualities in all states regarding the deployment of 3D engineered models for highway construction. Rather, it describes how one state—Iowa—uses 3D engineered models for construction of highway projects, from planning and surveying through design and construction.

Improving the Accuracy of Camber Predictions for Precast Pretensioned Concrete Beams, TR-625, 2015

The discrepancies between the designed and measured camber of precast pretensioned concrete beams (PPCBs) observed by the Iowa DOT have created challenges in the field during bridge construction, causing construction delays and additional costs. This study was undertaken to systematically identify the potential sources of discrepancies between the designed and measured camber from release to time of erection and improve the accuracy of camber estimations in order to minimize the associated problems in the field. To successfully accomplish the project objectives, engineering properties, including creep and shrinkage, of three normal concrete and four high-performance concrete mix designs were characterized. In parallel, another task focused on identifying the instantaneous camber and the variables affecting the instantaneous camber and evaluated the corresponding impact of this factor using more than 100 PPCBs. Using a combination of finite element analyses and the time-step method, the long-term camber was estimated for 66 PPCBs, with due consideration given to creep and shrinkage of concrete, changes in support location and prestress force, and the thermal effects. Utilizing the outcomes of the project, suitable long-term camber multipliers were developed that account for the time-dependent behavior, including the thermal effects. It is shown that by using the recommended practice for the camber measurements together with the proposed multipliers, the accuracy of camber prediction will be greatly improved. Consequently, it is expected that future bridge projects in Iowa can minimize construction challenges resulting from large discrepancies between the designed and actual camber of PPCBs during construction.

Effect of data acquisition accuracy on timing of stand harvests and expected net present value

Abstract

Predictive accuracy of original and recalibrated Framingham risk score in the Swiss population.

OBJECTIVE: To compare the predictive accuracy of the original and recalibrated Framingham risk function on current morbidity from coronary heart disease (CHD) and mortality data from the Swiss population. METHODS: Data from the CoLaus study, a cross-sectional, population-based study conducted between 2003 and 2006 on 5,773 participants aged 35-74 without CHD were used to recalibrate the Framingham risk function. The predicted number of events from each risk function were compared with those issued from local MONICA incidence rates and official mortality data from Switzerland. RESULTS: With the original risk function, 57.3%, 21.2%, 16.4% and 5.1% of men and 94.9%, 3.8%, 1.2% and 0.1% of women were at very low (<6%), low (6-10%), intermediate (10-20%) and high (>20%) risk, respectively. With the recalibrated risk function, the corresponding values were 84.7%, 10.3%, 4.3% and 0.6% in men and 99.5%, 0.4%, 0.0% and 0.1% in women, respectively. The number of CHD events over 10 years predicted by the original Framingham risk function was 2-3 fold higher than predicted by mortality+case fatality or by MONICA incidence rates (men: 191 vs. 92 and 51 events, respectively). The recalibrated risk function provided more reasonable estimates, albeit slightly overestimated (92 events, 5-95th percentile: 26-223 events); sensitivity analyses showed that the magnitude of the overestimation was between 0.4 and 2.2 in men, and 0.7 and 3.3 in women. CONCLUSION: The recalibrated Framingham risk function provides a reasonable alternative to assess CHD risk in men, but not in women.

Implementation of the Federal Highway Administration Final Rule on Work Zone Safety and Mobility, 2007

The Federal Highway Administration published the final rule updating 23 CFR 630 Subpart J in September 2004. The revised rule requires agencies using federal funding to address both safety and mobility in planning and construction of roadway improvements. The Iowa Department of Transportation (Iowa DOT) requested the assistance of the Center for Transportation and Research in developing guidance for a policy and procedures to comply with the final rule. This report describes an in-depth examination of current Iowa DOT project development processes for all types of improvements, including maintenance, as well as a detailed characterization of work zone impact considerations throughout project completion. To comply with both the letter and perceived intent of the final rule on safety and mobility, the report features a suggested work zone policy statement and suggested revisions in the Iowa DOT project development processes, including a definition of the key element: significant projects.

Towards a diffusion image processing validation and accuracy prediction framework

Validation is the main bottleneck preventing theadoption of many medical image processing algorithms inthe clinical practice. In the classical approach,a-posteriori analysis is performed based on someobjective metrics. In this work, a different approachbased on Petri Nets (PN) is proposed. The basic ideaconsists in predicting the accuracy that will result froma given processing based on the characterization of thesources of inaccuracy of the system. Here we propose aproof of concept in the scenario of a diffusion imaginganalysis pipeline. A PN is built after the detection ofthe possible sources of inaccuracy. By integrating thefirst qualitative insights based on the PN withquantitative measures, it is possible to optimize the PNitself, to predict the inaccuracy of the system in adifferent setting. Results show that the proposed modelprovides a good prediction performance and suggests theoptimal processing approach.