1,720,953 research outputs found
The use of a multi-set-up, reduced-scale accelerated trafficking simulator for evaluating roadway systems and products
No full textThis paper describes the use of an accelerated trafficking device, the one-third scale model mobile load simulator (MMLS3), for evaluating roadway systems and products. While the majority of accelerated load testers have focused on investigating rutting behaviours and moisture damage susceptibility of bituminous materials, this paper sheds light on broader applications using the MMLS3, including accelerated tests on field sections, scaled pavement structures, roadway reflective markings, roadway slip-resistant plates, in addition to performance evaluation tests on hot-mix asphalt mixtures. Results of experiments for the various applications indicate that the MMLS3, when equipped with ancillary instrumentation and devices, is a valuable tool for investigating the structural responses of a roadway system and for evaluating the effectiveness and durability of roadway pavement products. This study shows that the results of accelerated trafficking tests using the MMLS3 are comparable with field full-scale accelerated tests due to the nature of similitude in the MMLS3 design. Using the MMLS3 for accelerated traffic testing for practical and research purposes in the area of pavement engineering is a reliable and economical alternative to full-scale accelerated testing, given the savings in the required time and resources. © 2012 Copyright Taylor and Francis Group, LLC.Aktan F, 2004, TRANSPORT RES REC, P38; Al-Qadi L., 2007, TRB 2007 ANN M; Anderson D., 1984, 4 CYCLE PAVEMENT RES, V1; [Anonymous], 2007, ANN BOOK ASTM STAND; [Anonymous], 2007, ANN BOOK ASTM STAND; Barksdale R. D., 1989, 315 NCHRP TRANSP BOA; Bhattacharjee S., 2005, THESIS WORCESTER POL; Chehab G.R., 2007, FHWAPA2007009050110; Cooley Jr L. A., 2000, EC016 TRB NAT RES CO; Donnell ET, 2009, TRANSP RES RECORD, P76, DOI 10.3141-2107-08; Epps A. L., 2003, J TRANSPORTATION ENG, V129, P451, DOI 10.1061-(ASCE)0733-947X(2003)129:4(451); Epps A. L., 2001, 21341 TEX A M U TEX; Hufenus R, 2006, GEOTEXT GEOMEMBRANES, V24, P21, DOI 10.1016-j.geotexmem.2005.06.002; Hugo F. H., 2006, NCHRP SYNTHESIS HIGH; Kim S-M., 1995, 29141F U TEX CTR TRA; Lee S., 2003, THESIS N CAROLINA ST; Metcalf J. B., 1996, NCHRP SYNTHESIS HIGH; MLS Test Systems, 2003, MMLS3 OP MAN; Palacios C, 2008, PAVEMENT CRACKING: MECHANISMS, MODELING, DETECTION, TESTING AND CASE HISTORIES, P721; Pennsylvania Department of Transportation (PennDOT, 1995, PENNS DEP TRANSP PUB; Perkins S. S., 1999, FHWAMT990018138 US D; Smit A., 2004, P 2 INT APT C US SEA; Smit A., 1999, FHWATX00018142 U TEX; Smit A., 2003, TRB 82 ANN M; Tang X., 2008, GEOTECHNICAL SPECIAL, P1049; Tang X., 2008, GEOTECHNICAL SPECIAL, P1089; Xiaochao Tang, 2008, INT J PAVEMENT ENG, V9, P413, DOI 10.1080-102984308022798270
Evaluation of slip resistant plates for roadway applications
No full textThe presented study aims at evaluating the performance of slip resistant plates used in roadway construction to cover trenches, ditches, and potholes. Characteristics of the plate, including the surface friction, corrosion susceptibility, and resistance to abrasion are evaluated. Comparisons based on those attributes among various types of plates are conducted. The merit of the presented study mainly lies in the methodology and techniques adopted in evaluating the plates rather than ranking their performance. A customized corrosion tank built according to ASTM standards is used to apply salt fog spray on all the plates to induce corrosion. Surface friction is measured using the British Pendulum Tester for both uncorroded plates and corroded plates. To evaluate the abrasion resistance, the surfaces are subjected to wear and abrasion induced by repetitive wheel trafficking applied using the one third-scale Model Mobile Load Simulator. The drop in surface friction as a function of degree of corrosion and loading cycles is measured at regular intervals to evaluate the resistance to abrasion for each plate. Recommendations for improving the durability of the plates with welded deposits are suggested. Copyright by ASTM Int'l (all rights reserved).[Anonymous], 2008, ANN BOOK ASTM STAND; [Anonymous], 2006, ANN BOOK ASTM STAND; [Anonymous], ANN BOOK ASTM STAND; ASTM International, 2002, ANN BOOK ASTM STAND, P1; JACKSON M, 2003, BD273 DEP TRANSP; LEE YPK, 2004, APPL ADV TECHN TRANS; RADO Z, 2005, COMMUNICATION 0912; Tang X., 2008, GEOTECHNICAL SPECIAL, P1049; 2004, TRANSPORTATION ALTER0
Methodology for relating accelerated trafficking to field trafficking for pavement evaluation
No full textOver the years, numerous Accelerated Pavement Testing (APT) devices have been developed to facilitate quick evaluation of the performance and service life of pavements, materials, and related products under various loading and environmental climatic conditions. However, it is often challenging to translate or extrapolate the onset of distress, severity, and evolution caused by accelerated trafficking to that experienced in the field under different loading and environmental conditions. This is especially true if testing is conducted on specimens or reduced-scale slabs. The objective of this study is to present a methodology for establishing a relationship between accelerated and actual trafficking applied in the field. For this purpose, a Finite Element Method (FEM) analysis was conducted for specimens trafficked by the Model Mobile Load Simulator at 1-3rd scale (MMLS3) at conditions that favor rutting. As expected, it was observed that the rutting models developed and calibrated for field traffic do not accurately predict the rutting progression that was measured in these specimens. A methodology to more accurately predict rutting under accelerated trafficking is suggested, by which the loading effect of the MMLS3 is related to an equivalent 18-kip single axle load. New coefficients for the rutting model are devised to be used in conjunction with the MMLS3 testing. © 2014 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg.[Anonymous], 1962, 6 AASHO; Barksdale R., 1971, HIGHWAY RES REC, V345, P32; Bhattacharjee S., 2004, P 2 INT C ACC PAV TE; Epps A., 2004, EC044 TRB NAT RES CO; Epps M. A., 2002, P 9 INT C ASPH PAV C; Hua Jianfeng, 2000, THESIS PURDUE U; Huang Y. H., 1993, PAVEMENT ANAL DESIGN; Jenkins K. J., 2003, 22003 ITT U STELL; Kim S. M., 1995, 29141F U TEX AUST CT; Pirabarooban S., 2003, EVALUATION RUTTING P; Rabaiotti C., 2006, P GEOC GEOINST, V185, P55; Smit A. de F., 2004, P 2 INT C ACC PAV TE; Smit A. de F., 2002, P 9 INT C ASPH PAV; Sukumaran B., 2004, P FAA WORLDW AIRP TE; Tjan A., 2005, J E ASIA SOC TRANSPO, V6, P1194; Ven M. vd., 1998, J ASS ASPHALT PAVING, V67, P602; Walubita L. F., 2002, J SA I CIVIL ENG JOH, V44, P10
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Flexural behavior of concrete beams reinforced with different types of geogrids
No full textThis paper describes the behavior of geogrid-reinforced concrete members. The application of geogrids in concrete constitutes a new dimension for using geosynthetics in infrastructure. In pavement applications, geogrids have been used to provide confinement, stabilization, and reinforcement of unbound and asphalt concrete layers, as well as interlayers to mitigate reflective cracking. The ultimate objective of studying the behavior of geogrids in concrete members is to assess the feasibility and benefit of using geogrids in thin concrete overlays. The experimental program consisted of testing 21 simply supported plain and geogrid-reinforced beam specimens under four-point bending. The test parameters included three types of geogrids with different aperture shapes, physical and mechanical properties, and material composition. Additionally, two Portland cement concrete mixtures were used: normal and high strength. Results from testing confirm the reinforcing benefit of the geogrids as evidenced from the load-deflection response in terms of postpeak behavior, load capacity, crack mouth opening displacement (CMOD), and failure mode. Conclusions regarding correlations between the failure properties and the properties of the geogrid are made. © 2014 American Society of Civil Engineers.ASTM, 2010, C78C78M10 ASTM; Khodaii A, 2009, INT J CIV ENG, V7, P131; Maxwell S., 2005, 00924515 U WISC MAD; Webster S. L., 1993, GL936 US ARM CORPS E; Yu Q., 2009, THESIS U KANSAS LAWR0
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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