Device for Measuring Shear Resistance of Hot-Mix Asphalt in Gyratory Compactor

2000 ◽  
Vol 1723 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Murat Guler ◽  
Hussain U. Bahia ◽  
Peter J. Bosscher ◽  
Michael E. Plesha
Keyword(s):  
Hot Mix Asphalt ◽  
Low Cost ◽  
Design Procedure ◽  
Field Performance ◽  
Shear Resistance ◽  
Asphalt Mixtures ◽  
Interactive Effects ◽  
Continuous Measure ◽  
Highly Sensitive ◽  
The Relationship

The development of a gyratory load-cell and plate assembly (GLPA) to measure the shear resistance of hot-mix asphalt mixtures is described. The GLPA is a simple tool that allows the measurement of the eccentricity of the resultant load applied by the gyratory compactor in real time during compaction. The GLPA is inserted on top of the mixture specimen in the compaction mold, requiring no changes in the compaction procedure. The results from the GLPA give a continuous measure of the resistance of asphalt mixtures to shearing under gyratory loading at a fixed angle. On the basis of a simplified analysis, it is hypothesized that the bulk shear resistance estimated from the GLPA is a good indicator of the compactibility of asphalt mixtures and their potential resistance to rutting under traffic. The shear resistance and volumetric characteristics of a number of trial mixtures fabricated in the laboratory were tested to show the utility of the GLPA. The results show that the shear resistance is highly sensitive to gradation, asphalt content, and temperature. They also indicate that there are interactive effects of these factors that are independent of the volumetric properties. Although the relationship between the results of the GLPA and the field performance of mixtures is yet to be determined, this device has the potential to be a low-cost and effective tool to complement the current volumetric mixture design procedure. It provides a tool to measure an important mechanical property that is a good indicator of bulk shear resistance of asphalt mixtures.

Detecting and Expressing of Asphalt Materials Modulus Considering Temperature Effect

2015 ◽  
Vol 667 ◽  
pp. 347-352 ◽  
Author(s):  
Xiao Hua Luo ◽  
Qing Yang ◽  
Xin Qiu ◽  
Shang Lin Xiao
Keyword(s):  
Asphalt Mixture ◽  
Calculation Model ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Analysis Technique ◽  
Highly Sensitive ◽  
Multivariate Nonlinear Regression ◽  
Different Temperatures ◽  
Back Calculation ◽  
The Relationship

Asphalt mixtures have a highly sensitive and dependent on temperature. The typical modulus values of asphalt mixtures vary dramatically at different temperatures. Therefore, adjusting the modulus values of asphalt pavements of different testing temperatures to that of the criterion temperature condition is an important task to sustain asphalt mixtures modulus based the structural bearing capacity estimation of asphalt pavements comparable between time and space. According to the dynamic finite element numerical analysis method and the multivariate nonlinear regression analysis technique, the paper firstly established the back calculation model of asphalt mixtures modulus in term of the relationship between asphalt moduli and deflection basin parameters. Secondly, considering the correlation between the temperature at the middle of asphalt wearing course and the asphalt mixture modulus, the conversion analysis procedure of asphalt mixtures moduli of different temperatures was presented based on BELLS3 temperature adjustment coefficient method. Finally, the in-service monitoring over the existing pavements was conducted to test the validity of the procedure. The research provides a practical basis for evaluating pavement performance of asphalt wearing mixtures and a theory support for overlaying thickness design of asphalt pavements.

Interactive Effects of Acute Suicidal Affective Disturbance and Pain Persistence on Suicide Attempt Frequency and Lethality

Crisis ◽  
2019 ◽  
Vol 40 (6) ◽  
pp. 413-421 ◽  
Author(s):  
Megan L. Rogers ◽  
Thomas E. Joiner
Keyword(s):  
Suicide Attempt ◽  
Suicidal Behavior ◽  
Pain Perception ◽  
Suicide Attempts ◽  
Pain Tolerance ◽  
Self Report ◽  
Interactive Effects ◽  
Physical Pain ◽  
Affective Disturbance ◽  
The Relationship

Abstract. Background: Acute suicidal affective disturbance (ASAD) has been proposed as a suicide-specific entity that confers risk for imminent suicidal behavior. Preliminary evidence suggests that ASAD is associated with suicidal behavior beyond a number of factors; however, no study to date has examined potential moderating variables.  Aims: The present study tested the hypotheses that physical pain persistence would moderate the relationship between ASAD and (1) lifetime suicide attempts and (2) attempt lethality. Method: Students ( N = 167) with a history of suicidality completed self-report measures assessing the lifetime worst-point ASAD episode and the presence of a lifetime suicide attempt, a clinical interview about attempt lethality, and a physical pain tolerance task. Results: Physical pain persistence was a significant moderator of the association between ASAD and lifetime suicide attempts ( B = 0.00001, SE = 0.000004, p = .032), such that the relationship between ASAD and suicide attempts strengthened at increasing levels of pain persistence. The interaction between ASAD and pain persistence in relation to attempt lethality was nonsignificant ( B = 0.000004, SE = 0.00001, p = .765). Limitations: This study included a cross-sectional/retrospective analysis of worst-point ASAD symptoms, current physical pain perception, and lifetime suicide attempts. Conclusion: ASAD may confer risk for suicidal behavior most strongly at higher levels of pain persistence, whereas ASAD and pain perception do not influence attempt lethality.

Parenting Behaviors and Anxiety in Young Adults

2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock
Keyword(s):  
Effortful Control ◽  
Parenting Behaviors ◽  
Protective Role ◽  
Anxiety Symptoms ◽  
Interactive Effects ◽  
Parental Overprotection ◽  
High Control ◽  
Development Of Anxiety ◽  
The Relationship

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part I: Introduction and Details on the Organization of the Program

1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Aspect Ratio ◽  
Comprehensive Evaluation ◽  
Test Method ◽  
Interactive Effects ◽  
Data Analyses ◽  
Main Effect ◽  
Systematic Determination ◽  
Relationship Of ◽  
The Relationship

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.

Field Performance of a Constructed Litter Trap with Oil and Grease Filter using Low-cost Materials

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Siti Nazahiyah Rahmat ◽  
◽  
Algheethi Adel Ali Saeed Abduh ◽  
Ahmad Zurisman Mohd Ali ◽  
Mohd Adib Mohammad Razi ◽  
...  
Keyword(s):  
Low Cost ◽  
Field Performance ◽  
Oil And Grease

scholarly journals A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
High Volume ◽  
N Gene ◽  
Testing System ◽  
Target Sequence ◽  
One Pot ◽  
Sequence Detection ◽  
Highly Sensitive ◽  
Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

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