Evolution of the Surface Performance-Graded Specification for Chip Seal Binders

2017 ◽  
Vol 2632 (1) ◽  
pp. 32-43 ◽  
Author(s):  
Amy Epps Martin ◽  
Shi Chang ◽  
Swathi Mayi Theeda ◽  
Edith Arámbula-Mercado
Keyword(s):  
Field Performance ◽  
First Year ◽  
Department Of Transportation ◽  
The Past ◽  
Implementation Effort ◽  
Texas Department ◽  
Chip Seal ◽  
Surface Performance ◽  
Aggregate Loss ◽  
And Performance

Over the past 15 years, a surface performance-graded (SPG) specification for chip seal binders has been developed by the Texas Department of Transportation and has been validated with laboratory measurements and the visual field performance of 120 highway sections. The SPG specification was established in an effort to extend the service life of chip seals by providing a binder grading system and an associated selection method that ( a) accounted for differences in climate and ( b) used existing equipment and performance-based properties that precluded bleeding and aggregate loss in the critical first year of service after construction. A multiyear implementation effort of this specification is ongoing. This paper describes the motivation and evolution of the SPG specification, including a summary of the validation effort and a round robin testing program with the Texas Department of Transportation and suppliers of chip seal binders. Binder selection guidelines that use this specification are provided.

Results from Phase I of a Pilot Study on Dynamic Ramp Metering in Houston

2020 ◽  
Vol 2674 (11) ◽  
pp. 478-489
Author(s):  
Hongmin “Tracy” Zhou ◽  
Magdy Kozman
Keyword(s):  
Pilot Study ◽  
Phase I ◽  
Ramp Metering ◽  
Cost Ratio ◽  
Department Of Transportation ◽  
Benefit Cost Ratio ◽  
The Past ◽  
Texas Department ◽  
The Right ◽  
Benefit Cost

Traffic in Houston, U.S., has continued growing over the past decade. The Houston District of the Texas Department of Transportation (TxDOT) recently began a pilot study to evaluate a dynamic ramp metering system. The project is aimed to convert ramp metering from local control to system-wide dynamic operation. In Phase I of the project, major control parameters and different metering strategies were tested and evaluated in simulation and field settings for a study corridor installed with six ramp meters. The study identified a base metering plan that overall worked well for sites without restrictive queue conditions. This base plan was that average speed of 50 mph or lower in the right-most two mainlanes will call for metering at a constant metering rate of 850 vehicles per hour for at least 4 min, and that queue occupancy of 50% or higher will call for meter shutdown for at least 1 min. Ramp metering coordinated with the downstream intersection performed well by accommodating diverted traffic caused by ramp metering. When operating ramp meters in a group, metering the immediately upstream meter performed best compared with metering further upstream meters. It is evident that ramp metering caused traffic diversion to the frontage road and also caused reduced queue-jumping behaviors on the frontage road at ramp meters with an immediately upstream exit ramp. The coordinated ramp metering strategy can potentially generate a benefit/cost ratio of 117:1 compared with local metering in the District.

A Study of Blended Learning in a First-Year Chemistry for Engineers Course

2018 ◽  
Author(s):  
Jason Grove ◽  
Eline Boghaer
Keyword(s):  
Blended Learning ◽  
Engineering Students ◽  
Learning Activities ◽  
First Year ◽  
Student Interactions ◽  
Traditional Lecture ◽  
The Past ◽  
Problem Solving Strategies ◽  
And Performance ◽  
Compare And Contrast

Chemistry for Engineers is an introductory chemistry course taken by most engineering students at Waterloo during their first term. Over the past two years online content was developed to facilitate the implementation of blended learning. The motivation for this was: i) to create time for more valuable instructor–student interactions, allowing the instructor to reinforce challenging concepts, focus on problem-solving strategies and lead experiential learning activities, and, ii) to allow students to explore content at their own pace, thereby accommodating the diversity of students’ high-school chemistry preparation. Our study aims to compare and contrast student experience, satisfaction and performance between a blended learning and traditional lecture model of instruction through data from surveys and grades

Warrants for Active Warning Devices at Low-Volume Highway-Rail Grade Crossings

2012 ◽  
Author(s):  
Jaya Lakshmi Kunisetty ◽  
Angela Jannini Weissmann ◽  
Jose Weissmann ◽  
Mijia Yang ◽  
Steven P. Venglar
Keyword(s):  
Traffic Control ◽  
High Volume ◽  
The State ◽  
First Year ◽  
Department Of Transportation ◽  
Priority Index ◽  
Texas Department ◽  
Relevant Variables ◽  
Low Volume ◽  
Grade Crossings

The main objective of this research is to reduce the number of crashes between vehicles and trains at low-volume passive highway-rail at grade crossings by developing a revised safety index and warrants for active warning devices in the state of Texas. The research is focused only on low-volume crossings because most high-volume crossings in the state of Texas have already received improvements in terms of traffic control devices as the existing Texas priority index prioritizes high-volume crossings. This technical paper will describe and provide the most up-to-date preliminary results for warrants of the first year study in a two year Texas Department of Transportation (TxDOT) 0-6642 project called “Developing Warrants for Active Warning Devices at Low-Volume Highway-Rail Grade Crossings.” In order to prioritize the crossings that meet warrants a priority index should be used. The current Texas priority index places more emphasis on high-volume crossings with crash history and it doesn’t include several important variables. In order to address the issues of the current Texas priority index a new Texas Passive Crossing Index was developed based on a different concept — instead of using numeric thresholds, cumulative percentiles of the relevant variables are used.

Short-Term Field Performance and Cost-Effectiveness of Crumb-Rubber Modified Asphalt Emulsion in Chip Seal Applications

2021 ◽  
pp. 036119812110054
Author(s):  
Md Nafiur Rahman ◽  
Md Tanvir Ahmed Sarkar ◽  
Mostafa A. Elseifi ◽  
Corey Mayeux ◽  
Samuel B. Cooper ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Field Performance ◽  
Crumb Rubber ◽  
Department Of Transportation ◽  
Asphalt Emulsion ◽  
Short Term ◽  
Modified Asphalt ◽  
Application Rates ◽  
Chip Seal ◽  
Term Field

Chip sealing is a commonly used pavement maintenance technique that aims to delay pavement deterioration by reducing water infiltration and restoring skid resistance. The objective of this study was to evaluate the short-term field performance and cost-effectiveness of chip seals prepared with different types of asphalt emulsion and application rates. A newly introduced crumb-rubber modified asphalt emulsion was evaluated, one that allows chip seal installation at the same temperature as a standard emulsion. Types of emulsion included a crumb-rubber modified asphalt emulsion (CRS-2TR), a polymer-modified emulsion (CRS-2P), and a conventional unmodified emulsion (CRS-2). Application rates were obtained from the Louisiana Department of Transportation and Development (DOTD), the Texas Department of Transportation (DOT) specifications, and from the chip seal design method recommended in NCHRP Report 680. Seven chip seal sections were constructed and monitored regularly over a 12-month period. In the northbound lane, the chip seal section constructed with CRS-2TR (0.37 gal per square yard [gsy]) was the best performer statistically. In the southbound lane, the chip seal sections constructed with CRS-2TR and CRS-2P (0.31 gsy) performed similarly. Furthermore, the maximum Service Life Extension (SLE) was observed for the CRS-2TR (0.31 gsy) chip seal sections, whereas the chip seal sections constructed with CRS-2 had the lowest SLE. In addition, the most cost-effective chip seal section was achieved by the application of CRS-2TR emulsion at the Louisiana DOTD recommended emulsion application rate.

Development of Pavement Type Evaluation Procedure for Texas Department of Transportation

2000 ◽  
Vol 1699 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Muhammad Arif Beg ◽  
Zhanmin Zhang ◽  
W. Ronald Hudson
Keyword(s):  
Life Cycle Cost ◽  
Evaluation Procedure ◽  
Economic Evaluations ◽  
Life Cycle Cost Analysis ◽  
Department Of Transportation ◽  
Type Selection ◽  
Texas Department ◽  
Rational Procedure ◽  
And Performance

A rational procedure is presented for evaluating alternative pavement types for roadway projects. Agency costs, user delay costs, and performance levels are important factors for comparing alternative pavement strategies. These factors are included in the evaluation procedure. Economic evaluations are based on life-cycle cost analysis. Cost-effectiveness analysis is also included in the procedure and uses area under the performance curve as a measure of the effectiveness of a pavement design strategy. Limitations in economic evaluations and the role of other miscellaneous factors in pavement type selection are also discussed. A computer program, TxPTS, was developed to automate the evaluation procedure. Case studies are presented demonstrating the use of the program.

Relationship of stress and performance among first-year dental students

1986 ◽  
Vol 50 (5) ◽  
pp. 264-267 ◽  
Author(s):  
GH Westerman ◽  
TG Grandy ◽  
JV Lupo ◽  
RE Mitchell
Keyword(s):  
Dental Students ◽  
First Year ◽  
And Performance ◽  
Relationship Of

Performance of two combine harvester header in soybean crops

2020 ◽  
Vol 13 (2) ◽  
pp. 1
Author(s):  
E. M. Samogim ◽  
T. C. Oliveira ◽  
Z. N. Figueiredo ◽  
J. M. B. Vanini
Keyword(s):  
Experimental Design ◽  
Crop Yield ◽  
Field Performance ◽  
Travel Speed ◽  
The Other ◽  
Combine Data ◽  
Mato Grosso ◽  
Tukey Test ◽  
Combine Harvester ◽  
And Performance

The combine harvest for soybean crops market are currently available two types of combine with header or platform, one of conventional with revolving reel with metal or plastic teeth to cause the cut crop to fall into the auger header and the other called "draper" headers that use a fabric or rubber apron instead of a cross auger, there are few test about performance of this combine header for soybean in Mato Grosso State. The aim of this work was to evaluate the soybean harvesting quantitative losses and performance using two types combine header in four travel speed. The experiment was conducted during soybean crops season 2014/15, the farm Tamboril in the municipality of Pontes e Lacerda, State of Mato Grosso. The was used the experimental design of randomized blocks, evaluating four forward harvesting speeds (4 km h-1, 5 km h-1, 6 km h-1 and 7 km h-1), the natural crops losses were analyzed, loss caused by the combine harvester (combine header, internal mechanisms and total losses) and was also estimated the  field performance of each combine. Data were submitted to analysis of variance by F test and compared of the average by Tukey test at 5% probability. The results show the draper header presents a smaller amount of total loss and in most crop yield when compared with the conventional cross auger.

Progress and Prospects in Translating Nanobiotechnology in Medical Theranostics

2020 ◽  
Vol 16 (5) ◽  
pp. 685-707 ◽  
Author(s):  
Amna Batool ◽  
Farid Menaa ◽  
Bushra Uzair ◽  
Barkat Ali Khan ◽  
Bouzid Menaa
Keyword(s):  
Biological Properties ◽  
Chemical Characteristics ◽  
Intrinsic Properties ◽  
The Past ◽  
Profound Influence ◽  
Functionalized Nanomaterials ◽  
Physico Chemical ◽  
Properties Of Materials ◽  
Targeted Drug ◽  
And Performance

: The pace at which nanotheranostic technology for human disease is evolving has accelerated exponentially over the past five years. Nanotechnology is committed to utilizing the intrinsic properties of materials and structures at submicroscopic-scale measures. Indeed, there is generally a profound influence of reducing physical dimensions of particulates and devices on their physico-chemical characteristics, biological properties, and performance. The exploration of nature’s components to work effectively as nanoscaffolds or nanodevices represents a tremendous and growing interest in medicine for various applications (e.g., biosensing, tunable control and targeted drug release, tissue engineering). Several nanotheranostic approaches (i.e., diagnostic plus therapeutic using nanoscale) conferring unique features are constantly progressing and overcoming all the limitations of conventional medicines including specificity, efficacy, solubility, sensitivity, biodegradability, biocompatibility, stability, interactions at subcellular levels. : This review introduces two major aspects of nanotechnology as an innovative and challenging theranostic strategy or solution: (i) the most intriguing (bare and functionalized) nanomaterials with their respective advantages and drawbacks; (ii) the current and promising multifunctional “smart” nanodevices.

Pupil with Obsessive-Compulsive Disorder

2017 ◽  
Vol 7 (2) ◽  
pp. 7-25
Author(s):  
Karolina Diallo
Keyword(s):  
Obsessive Compulsive Disorder ◽  
School Performance ◽  
School Environment ◽  
Detrimental Effect ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
The Past ◽  
And Performance ◽  
The Impact

Pupil with Obsessive-Compulsive Disorder. Over the past twenty years childhood OCD has received more attention than any other anxiety disorder that occurs in the childhood. The increasing interest and research in this area have led to increasing number of diagnoses of OCD in children and adolescents, which affects both specialists and teachers. Depending on the severity of symptoms OCD has a detrimental effect upon child's school performance, which can lead almost to the impossibility to concentrate on school and associated duties. This article is devoted to the obsessive-compulsive disorder and its specifics in children, focusing on the impact of this disorder on behaviour, experience and performance of the child in the school environment. It mentions how important is the role of the teacher in whose class the pupil with this diagnosis is and it points out that it is necessary to increase teachers' competence to identify children with OCD symptoms, to take the disease into the account, to adapt the course of teaching and to introduce such measures that could help children reduce the anxiety and maintain (or increase) the school performance within and in accordance with the school regulations and curriculum.

scholarly journals Characterizing Bilingual Effects on Cognition: The Search for Meaningful Individual Differences

2021 ◽  
Vol 11 (1) ◽  
pp. 81
Author(s):  
Kristina C. Backer ◽  
Heather Bortfeld
Keyword(s):  
Individual Differences ◽  
Cognitive Processes ◽  
Language Background ◽  
Bilingual Advantage ◽  
The Past ◽  
General Movement ◽  
And Performance ◽  
Task Irrelevant ◽  
Analytical Approaches ◽  
The Relationship

A debate over the past decade has focused on the so-called bilingual advantage—the idea that bilingual and multilingual individuals have enhanced domain-general executive functions, relative to monolinguals, due to competition-induced monitoring of both processing and representation from the task-irrelevant language(s). In this commentary, we consider a recent study by Pot, Keijzer, and de Bot (2018), which focused on the relationship between individual differences in language usage and performance on an executive function task among multilingual older adults. We discuss their approach and findings in light of a more general movement towards embracing complexity in this domain of research, including individuals’ sociocultural context and position in the lifespan. The field increasingly considers interactions between bilingualism/multilingualism and cognition, employing measures of language use well beyond the early dichotomous perspectives on language background. Moreover, new measures of bilingualism and analytical approaches are helping researchers interrogate the complexities of specific processing issues. Indeed, our review of the bilingualism/multilingualism literature confirms the increased appreciation researchers have for the range of factors—beyond whether someone speaks one, two, or more languages—that impact specific cognitive processes. Here, we highlight some of the most salient of these, and incorporate suggestions for a way forward that likewise encompasses neural perspectives on the topic.

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