510 research outputs found

    Rutting, a Case Study (US 23, 1.5 miles north of Louisa)

    Get PDF
    This case study of rutting in an asphaltic concrete pavement makes recourse to trenching full width and full depth to expose and observe the entire cross section of the structure. Rutting occurred in the vicinity of Station 59+00 on US 23, 1.5 miles north of Louisa, during August and September 1983 when traffic was diverted onto newly constructed northbound lanes (without final surface and shouldering) while excavation into the hillside was completed for the southbound lanes. Earth movers crossed the northbound lanes going to and from a waste area. Coal trucks (Figures 1 and 2) slowed, stopped, and crept where rutting was greatest. Some rutting had occurred throughout

    Structural Capacity of In-Place Asphaltic Concrete Pavements from Dynamic Deflections

    Get PDF
    The proper design of asphaltic overlay thicknesses involves four major factors; the in-place modulus of the subgrade, an estimate of the structural capacity of the existing pavement, estimates of the future traffic expressed as equivalent axleloads and required or desired design levels, and a thickness design procedure. This paper deals with estimating the in-place subgrade modulus and the remaining load-carrying capacity of the existing pavement. The method presented herein is valid for any Road Rater or other dynamic tester such as the Dynaflect. This procedure was based upon a 600-pound (272.4-kg) peak-to-peak dynamic load applied at a rate of 25 Hz. The steady-state deflections have to be adjusted for load, dynamic frequency, and location of sensors. This method should be applied only to those testers that use a constant vibratory load

    Pavement Roughness In Kentucky

    Get PDF
    Over two hundred pavement sections in Kentucky have been periodically measured for pavement roughness over a period of several years. This pavement service-life historical data can be used to assess quality of construction, pavement service-life, present and anticipated pavement condition. Road users perception of ride quality can be related to these measurements. Response-type road roughness measuring systems have been used to collect roughness measurements and correlation studies have been performed to relate measurements from current systems. Several factors influence pavement roughness. An early factor is construction workmanship. Other factors are traffic loading, environment, geology, and age

    Sandstone as a Construction Material KY 80, Hazard to Watergap

    Get PDF
    KY 80 (Hazard to Watergap) was constructed using abundantly available crushed sandstone. The pavements were designed to have adequate load-carrying capibilities and stability but were considered to be experimental (see Figure 1). It was intended that performance would be monitored and that undesirable features and performance would be identified and studied. Such surveillance was discontinued before construction was completed. Recently, the need has arisen for testing and evaluation of some of the experimental sections. Some spalls, scuffs, and artesian water have been observed. Excessive water has appeared in the shoulder, median, and mainline. There has been at least one spot failure. The Kentucky Transportation Research Program was asked to submit a work plan to evaluate the performance of some experimental features. A plan was approved, and the investigations began on October 1, 1982. At this time, the investigative work includes the section of KY 80 from Milepost 9 to Milepost l8. Some data were already available for sections near the Floyd-Knott County line. Those data were obtained in l981 while conducting a study of in-place strength characteristics of sandstone rock subgrades. The investigation reported herein involved the following: condition survey and photologging; Road Rater testing and survey; coring, drilling, and sampling of pavement materials; and testing of cores and samples recovered from the pavement

    Dynamic changes in lung microRNA profiles during the development of pulmonary hypertension due to chronic hypoxia and monocrotaline

    Get PDF
    <b>Objective</b>: MicroRNAs (miRNAs) are small noncoding RNAs that have the capacity to control protein production through binding "seed" sequences within a target mRNA. Each miRNA is capable of potentially controlling hundreds of genes. The regulation of miRNAs in the lung during the development of pulmonary arterial hypertension (PAH) is unknown.<p></p> <b>Methods and Results</b>: We screened lung miRNA profiles in a longitudinal and crossover design during the development of PAH caused by chronic hypoxia or monocrotaline in rats. We identified reduced expression of Dicer, involved in miRNA processing, during the onset of PAH after hypoxia. MiR-22, miR-30, and let-7f were downregulated, whereas miR-322 and miR-451 were upregulated significantly during the development of PAH in both models. Differences were observed between monocrotaline and chronic hypoxia. For example, miR-21 and let-7a were significantly reduced only in monocrotaline-treated rats. MiRNAs that were significantly regulated were validated by quantitative polymerase chain reaction. By using in vitro studies, we demonstrated that hypoxia and growth factors implicated in PAH induced similar changes in miRNA expression. Furthermore, we confirmed miR-21 downregulation in human lung tissue and serum from patients with idiopathic PAH.<p></p> <b>Conclusion</b>: Defined miRNAs are regulated during the development of PAH in rats. Therefore, miRNAs may contribute to the pathogenesis of PAH and represent a novel opportunity for therapeutic intervention.<p></p&gt

    Jefferson Freeway Investigation (Westbound Lanes)

    Get PDF
    The Kentucky Transportation Research Program (KTRP) was retained to perform an investigation for the Kentucky Department of Highways to assess damage that may be attributed to passage of the Model 992C over portions of the Jefferson Freeway. KTRP investigators conducted visual surveys, performed Road Rater deflection tests, did in-place California Bearing Ratio (CBR) testing on subgrade materials, obtained pavement cores, and conducted laboratory tests and analyses. It appeared the pavement was damaged by the front-end loader. No evidence of damage to the bridges attributable to the front-end loader was detected. Damage to the pavement attributable to passage of the front-end loader was assessed in the amount of $322,074.50

    Academic self-concept, gender and single-sex schooling

    Get PDF
    This paper assesses gender differences in academic self-concept for a cohort of children born in 1958 (the National Child Development Study). We address the question of whether attending single-sex or co-educational schools affected students’ perceptions of their own academic abilities (academic self-concept). Academic selfconcept was found to be highly gendered, even controlling for prior test scores. Boys had higher self-concepts in maths and science, and girls in English. Single-sex schooling reduced the gender gap in self-concept, while selective schooling was linked to lower academic self-concept overall

    Autobiography as unconventional history: Constructing the author

    Get PDF
    The experience of historians as autobiographers has led them to reconsider the nature of historical knowledge and the function of the historian as an intermediary between the past and present. In the new theoretical context of the social sciences and historiography, we can take this proposal further and consider autobiography as a valid form of history—or, at least, as ‘unconventional history’, understood as negotiations with history that transcend or subvert traditional chronological monographs, posit the ‘subjective’ as a useful form of knowledge, and engage the constructed nature of the text. Taking this hypothesis as a starting point, this article reads historians' autobiographical texts to explore if we can/should continue to defend the classic distinction between subject and object, historian scientist and historian author. In this article I compare the work of several historian autobiographers that permit us to identify different methodologies in approaching the story of the self that also reflects different theoretical conceptions of history. I argue that historians that may be considered ‘constructionist’, such as Fernand Braudel, Annie Kriegel, George Duby, and Eric Hobsbawm, design their autobiographies in the same way they articulate their historical texts: by foregrounding objectivity and establishing critical distance between the subject—the historian who narrates the story—and the object—one's own life. Unconventional or experimental approaches, such as those espoused by Robert Rosenstone, Dominick LaCapra, or Clifford Geertz, result in more self-conscious autobiographies, which are, paradoxically, often more realistic and more revealing of the epistemological nature of life writing. ----------------- La experiencia de los historiadores como autobiógrafos les ha llevado a reconsiderar la naturaleza del conocimiento histórico y la función del historiador como un intermediario entre el pasado y el presente. En el nuevo contexto teórico de las ciencias sociales y la historiografía podemos tomar esta propuesta más allá y considerar la autobiografía como una forma válida de historia-o, al menos, de historia ‘poco convencional’-, entendida como negociaciones con la historia que trascienden o subvierten las tradicionales monografías cronológicas, plantean lo "subjetivo" como una forma útil de conocimiento y participan de la naturaleza construida del texto. Tomando esta hipótesis como punto de partida, este artículo lee los textos autobiográficos de los historiadores para explorar si se puede / debe seguir defendiendo la clásica distinción entre sujeto y objeto, historiador científico e historiador escritor. En este artículo comparo el trabajo de varios historiadores autobiógrafos que nos permiten identificar las diferentes metodologías para acercarse a la historia del yo y que también reflejan las diferentes concepciones teóricas de la historia. Sostengo que los historiadores que pueden considerarse "constructivistas", como Fernand Braudel, Annie Kriegel, George Duby y Eric Hobsbawm, diseñan sus autobiografías de la misma forma que articulan sus textos históricos: poniendo en primer plano la objetividad y estableciendo una distancia crítica entre el sujeto -el historiador que narra la historia-y el objeto- la vida de cada uno. Enfoques no convencionales o experimentales, como los expuestos por Robert Rosenstone, Dominick LaCapra, o Clifford Geertz, resultan autobiografías más autoconscientes, que son, paradójicamente, a menudo más realistas y más reveladoras de la naturaleza epistemológica de la escritura de la vida
    corecore