scholarly journals Viastructura – A New Way Of Pavement Structure Design

2021 ◽  
Vol 1202 (1) ◽  
pp. 012018
Author(s):  
Audrius Vaitkus ◽  
Rita Kleizienė ◽  
Martynas Karbočius
Keyword(s):  
Layer Thickness ◽  
Construction Materials ◽  
The United States ◽  
Structure Design ◽  
Test Results ◽  
Additional Function ◽  
Structure Selection ◽  
Laboratory Test Results ◽  
Pavement Structure ◽  
Pavement Structures

Abstract The catalogues of standard pavement structures are common way to design road pavements. In 2019, new regulation for the design of standard pavement structures KPT SDK 19 was issued in Lithuania. One of the new requirements require verification of layer thickness of high-class pavement structures. Such verification should be done by internationally approved mechanistic-empirical methods. In addition, it is recommended to use the same methods to adjust the layer thickness of the selected standard pavement structure for lower classes. These calculations are particularly applicable when the design load (ESAL) is at the lower or upper limit of the class range. Vilnius Tech Road Research Institute experts and outsource IT specialists spent two years for the design model ViaStructura development. Web software based on mechanistic-empiric approach include the boundary conditions, based on Austria, the United States and Germany experience and laboratory test results of construction materials. Materials can be selected from created database, which can be simply expanded with the new materials by the user. as Additional function allow comparison of separate designed pavement structures. The article present the concept of the ViaStructura model for the design of flexible pavement structures, reveals its main principles and advantages comparing to the pavement structure selection by the standard catalogue.

Sponge roads: the permeable asphalt pavement structures based on rainfall characteristics in central plains urban agglomeration of China

2019 ◽  
Vol 80 (9) ◽  
pp. 1740-1750 ◽  
Author(s):  
Xiaodong Guo ◽  
Jiupeng Zhang ◽  
Bochao Zhou ◽  
Wolong Liu ◽  
Jianzhong Pei ◽  
...  
Keyword(s):  
Surface Layer ◽  
Bearing Capacity ◽  
Asphalt Pavement ◽  
Structure Design ◽  
Urban Agglomeration ◽  
Central Plains ◽  
Rainfall Characteristics ◽  
Combination Scheme ◽  
Pavement Structure ◽  
Pavement Structures

Abstract Permeable asphalt pavement should be selected according to the rainfall characteristics of the project site, so as to improve the permeable performance and ensure the bearing capacity of the pavement structure. Therefore, taking a city in the central plains urban agglomeration of China as an example, the characteristics of the rainstorm intensity distribution and cumulative rainfall are analyzed, and a combination scheme of drainage surface layer asphalt pavement suitable for rainfall characteristics in this area is proposed. Then, the pavement structure design is systematically carried out based on the permeable capacity and bearing capacity. The results show that under the rainfall conditions in this area, there is no surface runoff on the permeable asphalt pavement with 120 mm drainage surface layer, which is suitable for the medium traffic grade of urban roads with cumulative equivalent axle loads of 10 million to 12 million times.

scholarly journals LabRS: A Rosetta stone for retrospective standardization of clinical laboratory test results

2017 ◽  
Vol 25 (2) ◽  
pp. 121-126 ◽  
Author(s):  
Ronald George Hauser ◽  
Douglas B Quine ◽  
Alex Ryder
Keyword(s):  
Laboratory Tests ◽  
Standardized Test ◽  
Clinical Laboratory ◽  
Secondary Data ◽  
The United States ◽  
Test Results ◽  
Original Result ◽  
Clinical Laboratories ◽  
Laboratory Test Results ◽  
Standardization Process

Abstract Objective Clinical laboratories in the United States do not have an explicit result standard to report the 7 billion laboratory tests results they produce each year. The absence of standardized test results creates inefficiencies and ambiguities for secondary data users. We developed and tested a tool to standardize the results of laboratory tests in a large, multicenter clinical data warehouse. Methods Laboratory records, each of which consisted of a laboratory result and a test identifier, from 27 diverse facilities were captured from 2000 through 2015. Each record underwent a standardization process to convert the original result into a format amenable to secondary data analysis. The standardization process included the correction of typos, normalization of categorical results, separation of inequalities from numbers, and conversion of numbers represented by words (eg, “million”) to numerals. Quality control included expert review. Results We obtained 1.266 × 109 laboratory records and standardized 1.252 × 109 records (98.9%). Of the unique unstandardized records (78.887 × 103), most appeared <5 times (96%, eg, typos), did not have a test identifier (47%), or belonged to an esoteric test with <100 results (2%). Overall, these 3 reasons accounted for nearly all unstandardized results (98%). Conclusion Current results suggest that the tool is both scalable and generalizable among diverse clinical laboratories. Based on observed trends, the tool will require ongoing maintenance to stay current with new tests and result formats. Future work to develop and implement an explicit standard for test results would reduce the need to retrospectively standardize test results.

scholarly journals Design solutions for pavements structure affected by static and impact load

2014 ◽  
Vol 9 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Audrius Vaitkus ◽  
Viktoras Vorobjovas ◽  
Judita Gražulytė ◽  
Rita Kleizienė ◽  
Ovidijus Šernas ◽  
...  
Keyword(s):  
Impact Load ◽  
Climatic Conditions ◽  
Waste Utilization ◽  
Structure Design ◽  
Pavement Performance ◽  
Impact Loads ◽  
Main Factors ◽  
Pavement Structure ◽  
Pavement Structures ◽  
In The Beginning

Pavements of aprons, container and logistic terminals, areas of storage, parking lots, areas of waste utilization are affected by high pressure static and impact loads. These loads strongly influence pavement performance by causing permanent deformations and distresses in the surface and even sometimes pavement failure in the beginning of pavement service. The types of structure, materials and layer thicknesses are the main factors relative to pavement performance. In order to correctly understand the particularity of static and impact loading, distresses of pavement structures affected by such load are emphasized, the load specification and climatic conditions influencing pavement performance are characterized. After analysis of the best practise, the flow chart of pavement structure design model was introduced. The paper gives reasonable pavement type and thickness determination dependent on object of application pavement structure.

Effect of Allowable Thickness Variation on Backcalculated Moduli

1998 ◽  
Vol 1639 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Fritz Jooste ◽  
Stephen V. Kekwick ◽  
Marshal Muthen
Keyword(s):  
Layer Thickness ◽  
Thickness Variation ◽  
Individual Data ◽  
Significant Extent ◽  
Data Set ◽  
Construction Specifications ◽  
Data Points ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Thickness Variations

The effect of small variations in pavement layer thicknesses on the accuracy of backcalculated moduli was investigated. Deflection data were generated using simulated pavement structures in which layer thicknesses were varied by small amounts. This variation in layer thicknesses was kept sufficiently small so that all layers would conform to construction specifications. A backcalculation was then performed on the generated deflection data. Only the average design thicknesses were supplied to the backcalculation software. Errors between backcalculated moduli and those moduli that were used to generate the deflection data were then studied. It was found that even small variations in layer thicknesses influenced the accuracy of the backcalculated moduli to a significant extent. Where the subgrade depth was considered to be variable, the backcalculation error due to small variations in layer thicknesses was at least 5 percent. For the pavement structures studied, the subbase layer proved to be most sensitive to layer thickness variations. The subgrade appeared to be least sensitive to small variations in layer thicknesses. Thin, stiff layers such as a stabilized subbase were found to be most sensitive of all to layer thickness fluctuations. Despite the large variations in backcalculated moduli at individual data points, the average backcalculated moduli for the entire data set of each pavement structure compared well with the correct modulus value (i.e, the modulus values used to generate the deflection data).

scholarly journals PROCEDURES FOR DIMENSION OF FLEXIBLE ROAD CONSTRUCTIONS

2019 ◽  
pp. 625-630
Author(s):  
Aleksandar Glavinov ◽  
Gorgi Dimov ◽  
Nikola Zlatanov
Keyword(s):  
Road Construction ◽  
Federal Aviation Administration ◽  
Computer Programs ◽  
The United States ◽  
The State ◽  
Group Method ◽  
Layer System ◽  
The Us ◽  
Pavement Structure ◽  
Pavement Structures

Experience and procedures for dimension of flexible road construction structures is a complex process. Therefore, several dimension methods are used: ASHTO formed in 1959 in the state of Illinois, USA, Federal Association for Public Roads and Transport AASHTO 2004, methods of the Institutes for asphalt formed in 1955 in England ASSHO and WASHO, method of the SHELL group and method of (FAA) Federal Aviation Administration USA. Methods for collecting data and accumulating them in an appropriate project include design levels, predictions of damage, unevenness, assessment of characteristics, design reliability, expected costs, dimension, and predicting the behavior of pavement structures. The AASNTO method is based on the results of an experiment made in the state of Illinois in 1959 and 1960, and the first guideline was published in 1961 since then, updates have been published regularly to track down the latest findings in the area of pavement structures. There are also computer programs designed for using this method, one of which is "FLEXPAVE". The ASSOA and WASHO method appeared in 1955 in England, it is implemented by the asphalt institute. In the upcoming years this method was upgraded in collaboration with the US engineering corps, the US government agencies and the most famous numerical procedures for the time, as well as computer programs "DAMA" "BISAR "And" CHEVRON ". This software enables the monitoring of monthly changes in condition and destruction by entering the corresponding input data. Through the SHELL group method, the pavement structure is viewed as a linear elastic multi-layer system whose layers have their own characteristics that are expressed through the modulus of elasticity Poisson's coefficient. The traffic is expressed through an ESA - an equivalent standard axis, which acts vertically and it is equally distributed over one or more circular surfaces. Through the (FAA) method, the Federal Aviation Administration in the United States has issued a manual for the dimension of pavement structures depending on the mass of the plane, based on its own classification of the ground, the characteristics of the materials that are part of the pavement structure, the loading of the main aircraft, repetition of the load and the frost effect. Based on these parameters, the thickness of the pavement structure is determined. Today, there is software based on the finite element principles of FEAFAA, FEDFAA, BAKFAA return program, and a program for determining the ACN number COMFAA

scholarly journals The influence of CBR parameters of low-frost-susceptible soils on the process of airport pavement design

2018 ◽  
Vol 67 (3) ◽  
pp. 155-164
Author(s):  
Jan Marszałek ◽  
Ryszard Chmielewski ◽  
Damian Waliszewski
Keyword(s):  
Surface Layer ◽  
Layer Thickness ◽  
Laboratory Testing ◽  
Pavement Design ◽  
California Bearing Ratio ◽  
Test Results ◽  
Airport Pavement ◽  
Laboratory Test Results ◽  
Cbr Test ◽  
Surface Layer Thickness

The paper presents the issue of layer thickness selection in designing of concrete airport pavements depending on the values of soil substrate calculation parameters. This analysis is based on laboratory testing of low-frost-susceptible soils, specifically silty sands of various silt content, for which the California Bearing Ratio values were determined [1, 2]. Dimensioning methods used in airport pavement design are presented, together with their brief descriptions. Comparative calculations of surface layer thickness depending on the interpretation of the obtained CBR laboratory test results are performed. Differences in airport pavement layer thickness resulting from the assumed CBR values are presented. A correction of the results of pavement calculations based on the California bearing ratio is proposed. Keywords: airport pavement, CBR test, pavement dimensioning, soil subtrate, low-frost-susceptible soil.

Morning Rounds Inpatient Test Availability

2000 ◽  
Vol 124 (4) ◽  
pp. 499-503 ◽  
Author(s):  
David A. Novis ◽  
Jane C. Dale
Keyword(s):  
The United States ◽  
Early Morning ◽  
Physician Satisfaction ◽  
Test Results ◽  
Improvement Program ◽  
Public And Private ◽  
Laboratory Service ◽  
Practice Characteristics ◽  
Laboratory Services ◽  
Laboratory Test Results

Abstract Objectives.—To determine the success with which laboratories were able to report morning test results on time, the laboratory practice characteristics associated with improved success, and the degree of satisfaction among clinicians with the timeliness of laboratory service. Design.—Hospital laboratories participating in the College of American Pathologist Q-Probes laboratory quality improvement program prospectively calculated the percentages of morning-run complete blood cell count (CBC) and electrolyte results that were reported on or before predetermined reporting deadlines, completed questionnaires concerning their departments' practice characteristics as they related to performing morning blood work, and distributed to physician utilizers of morning laboratory services questionnaires evaluating physician satisfaction with laboratory services. Setting and Participants.—A total of 367 public and private institutions located in the United States (355), Canada (5), Australia (2), and 1 each in the United Kingdom, Spain, Brazil, Korea, and Guam. Main Outcome Measure.—The percentages of morning-run CBC and electrolyte results reported on or before predetermined reporting deadlines. Results.—Participants submitted data on 40 256 CBC and 39 604 electrolyte specimens. In aggregate, a total of 88.9% of these tests (90.2% of CBCs and 87.6% of electrolytes) were reported on or before the reporting deadlines that the participating laboratories set for themselves. Half of the participants reported 94.6% of their CBC results and 95.5% of their electrolyte results on or before their self-imposed reporting deadlines. No specific demographic features or departmental practice characteristics were associated with higher or lower rates of institutional reporting compliance. Most physician utilizers of early-morning laboratory test results believed that the laboratory is sensitive to and meets the needs of clinicians for timely reporting of early-morning test results. Conclusions.—Most laboratories are capable of reporting 95% of their routine morning laboratory tests on time, and most physicians are satisfied with their laboratories' morning testing service.

scholarly journals Recommendation of Suitable Loading Waveforms and Wavelength Equations for Dynamic Modulus Based on Measured Wheel Loads

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Xiongwei Dai ◽  
Xiaodi Hu ◽  
Ying Gao
Keyword(s):  
Compressive Stress ◽  
Dynamic Modulus ◽  
Least Squares Method ◽  
Structure Design ◽  
Vertical Stress ◽  
Finite Element Program ◽  
Stress Pulse ◽  
Different Depths ◽  
Pavement Structure ◽  
Pavement Structures

Dynamic modulus is a key parameter in the pavement structure design and analysis. A haversine loading waveform is the most widely recommended waveform in the laboratory to obtain the dynamic modulus of asphalt mixtures by test protocols, which may not completely represent all field loading conditions. The aim of this study is to investigate the suitable vertical compressive stress pulse waveforms at different depths under different pavement structures and to obtain the best fitting waveforms by using the least squares method. Specifically, the vertical compressive stress of different pavement structures was calculated by utilizing a three-dimensional finite element program incorporating with the measured wheel loads. The results revealed that the vertical stress pulse waveforms at different depths in asphalt layer were different within different pavement structure combinations. Generally, the square waveform fitted the vertical stress pulse waveform better for the shallow depth of the surface layer. The haversine waveform became more suitable while the depth increased. The bell waveform was better when the depth went deeper (i.e., 10 cm). In addition, the method of choosing waveforms at different depths of different pavement structures was provided, and the equation of calculating wavelength was recommended. Moreover, dynamic modulus under different loading waveforms were analysed through laboratory test, and the process for obtaining dynamic modulus of asphalt layer in any depth was presented.

scholarly journals Real-world data suggest antibody positivity to SARS-CoV-2 is associated with a decreased risk of future infection

2020 ◽  
Author(s):  
Raymond A. Harvey ◽  
Jeremy A. Rassen ◽  
Carly A. Kabelac ◽  
Wendy Turenne ◽  
Sandy Leonard ◽  
...  
Keyword(s):  
Real World ◽  
Antibody Test ◽  
The United States ◽  
Test Results ◽  
Real World Data ◽  
World Data ◽  
Positive Antibody ◽  
Laboratory Test Results ◽  
Over Time

AbstractImportanceThere is limited evidence regarding whether the presence of serum antibodies to SARS-CoV-2 is associated with a decreased risk of future infection. Understanding susceptibility to infection and the role of immune memory is important for identifying at-risk populations and could have implications for vaccine deployment.ObjectiveThe purpose of this study was to evaluate subsequent evidence of SARS-CoV-2 infection based on diagnostic nucleic acid amplification test (NAAT) among individuals who are antibody-positive compared with those who are antibody-negative, using real-world data.DesignThis was an observational descriptive cohort study.ParticipantsThe study utilized a national sample to create cohorts from a de-identified dataset composed of commercial laboratory test results, open and closed medical and pharmacy claims, electronic health records, hospital billing (chargemaster) data, and payer enrollment files from the United States. Patients were indexed as antibody-positive or antibody-negative according to their first SARS-CoV-2 antibody test recorded in the database. Patients with more than 1 antibody test on the index date where results were discordant were excluded.Main Outcomes/MeasuresPrimary endpoints were index antibody test results and post-index diagnostic NAAT results, with infection defined as a positive diagnostic test post-index, as measured in 30-day intervals (0-30, 31-60, 61-90, >90 days). Additional measures included demographic, geographic, and clinical characteristics at the time of the index antibody test, such as recorded signs and symptoms or prior evidence of COVID-19 (diagnoses or NAAT+) and recorded comorbidities.ResultsWe included 3,257,478 unique patients with an index antibody test. Of these, 2,876,773 (88.3%) had a negative index antibody result, 378,606 (11.6%) had a positive index antibody result, and 2,099 (0.1%) had an inconclusive index antibody result. Patients with a negative antibody test were somewhat older at index than those with a positive result (mean of 48 versus 44 years). A fraction (18.4%) of individuals who were initially seropositive converted to seronegative over the follow up period. During the follow-up periods, the ratio (CI) of positive NAAT results among individuals who had a positive antibody test at index versus those with a negative antibody test at index was 2.85 (2.73 - 2.97) at 0-30 days, 0.67 (0.6 - 0.74) at 31-60 days, 0.29 (0.24 - 0.35) at 61-90 days), and 0.10 (0.05 - 0.19) at >90 days.ConclusionsPatients who display positive antibody tests are initially more likely to have a positive NAAT, consistent with prolonged RNA shedding, but over time become markedly less likely to have a positive NAAT. This result suggests seropositivity using commercially available assays is associated with protection from infection. The duration of protection is unknown and may wane over time; this parameter will need to be addressed in a study with extended duration of follow up.Key PointsQuestionCan real-world data be used to evaluate the comparative risk of SARS-CoV-2 infection for individuals who are antibody-positive versus antibody-negative?FindingOf patients indexed on a positive antibody test, 10 of 3,226 with a NAAT (0.3%) had evidence of a positive NAAT > 90 days after index, compared with 491 of 16,157 (3.0%) indexed on a negative antibody test.MeaningIndividuals who are seropositive for SARS-CoV-2 based on commercial assays may be at decreased future risk of SARS-CoV-2 infection.

Anticoagulant Management of Atrial Fibrillation In the United States: Findings From a Large National Database of Clinical Test Results (Quest Diagnostics Health Trends™ Report).

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1103-1103 ◽  
Author(s):  
Jeffrey S. Dlott ◽  
Roberta George ◽  
Xiaohua Huang ◽  
Muneer Odeh ◽  
Harvey W. Kaufman ◽  
...  
Keyword(s):  
United States ◽  
Atrial Fibrillation ◽  
The United States ◽  
Geographic Region ◽  
National Database ◽  
Clinical Test ◽  
Test Results ◽  
Anticoagulation Management ◽  
Data Set ◽  
Laboratory Test Results

Abstract Abstract 1103 Background: Control of anticoagulation during warfarin therapy, as assessed by international normalized ratio (INR), is variable even under optimal conditions. Time in therapeutic range (TTR) has been shown to correlate with the important outcomes of hemorrhage or thrombosis. In this study we assessed the current patterns and quality of anticoagulation management among individuals with atrial fibrillation (AF) compared to venous thromboembolism (VTE) using data extracted from a large, nationally representative database of laboratory results in the United States. Methods: The Quest Diagnostics database of laboratory test results, inclusive of all 50 states, was queried for all outpatient INR testing for patients ≥ 18 years of age with AF (ICD-9-CM code 427.31) and compared to those with venous thromboembolic disease (286, 415, 453). To achieve a robust data set for trend analysis, the following inclusion criteria were applied: 1) ≥2 INR results >1.2 during a 12-month period; and 2) ≤60-day interval between consecutive INR measurements. TTR was calculated as % days in range (Rosendaal method) and % INR measurements in range. The data were also analyzed for trends by age, gender, frequency of monitoring, and geographic region (as defined by the US Department of Health and Human Services). Results: Overall, 187,573 individuals were included (74% with AF), with a total of 3,493,443 INR measurements. The demographics of the AF and VTE cohorts, frequencies of INR measurements, and TTR findings are summarized in Table 1. The INR distributions for proportions in-range and out-of-range are shown in Table 2. Both the AF and VTE cohorts had significantly lower TTR for patients <45 years old and slightly (∼2-3%) higher TTR for males among most age groups (data not shown). Geographic regions with more frequent INR measurements also tended to have higher TTR; at opposite end of the spectrum, the Northeast (Region 1) showed a mean of 25.2 visits per year and a TTR (in days) of 60.3%, while the Southwest (Region 6) had a mean of 17.5 visits per year and a TTR of 52.8%. Conclusions: This data set represents one of the largest analyses of INR control of warfarin in the United States. The TTR data demonstrate suboptimal anticoagulation in a substantial proportion of INR visits, suggesting that a large proportion of Americans with AF are not receiving the optimum warfarin effect. Corroborating other studies, our data suggest a positive relationship between increased monitoring and INR control, as demonstrated by the regional differences in TTR. Younger patients (<45 y) had significantly lower TTRs than did older patients, and women tended to have lower TTR across most age categories. Taken together, these findings suggest that strategies are needed to improve oral anticoagulation care in the United States. Disclosures: Ansell: Bayer, Inc: Consultancy; Bristol Myers Squibb: Consultancy, Data Safety Monitoring Boards; Daiichi Sankyo: Consultancy; Boehringer Ingleheim: Consultancy; Ortho McNeil: Consultancy; Sanofi Aventis: Speakers Bureau.

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