1,332 research outputs found
Full-Depth Reclamation (FDR) for Suburban/Urban and Local Roads Application
No full textFull-depth reclamation (FDR) as a rehabilitation method improves the service life of pavement structures by reusing asphalt materials, thereby reducing costs and allowing for conservation of nonrenewable resources. However, the lack of mechanicsbased material testing procedures and performance-based specifications limit the use of FDR processes. First, the FDR design and construction process are presented, then, a literature review focusing on FDR research is completed, and a survey is conducted to obtain relevant information regarding current FDR practices in Minnesota. Next, Indirect Tensile Test (IDT) and Dynamic Modulus Test in IDT mode testing is performed on four FDR materials: Field mixed, Lab compacted; Lab mixed, Lab compacted; FDR with cement additive; and FDR with graphene nanoplatelet (GNP) additive. Two curing times are used to determine how physical properties change over time. Test results are used to perform simulations in MnPAVE software and a Life Cycle Cost Analysis (LCCA). Laboratory observations indicate that cement additive reduces predicted life and increases critical cracking temperature with a slight increase in cost; GNP additive reduces predicted life but also reduces critical cracking temperature with a significant cost increase; Lab mixed samples performed better than Field mixed, suggesting that field methods could be improved; and curing has a positive effect on the FDR materials with cement and GNP additives--for both materials, the dynamic modulus increase, and the GNP samples also had a slight increase in tensile strength. MnPAVE simulations and LCCA results indicate that over a 35-year period, FDR may be a more cost-effective method than traditional mill and overlay.Hartman, Marcella; Turos, Mugur; Ghosh, Debaroti; Marasteanu, Mihai. (2016). Full-Depth Reclamation (FDR) for Suburban/Urban and Local Roads Application. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/185541
Ghosh, the shadow lines, and the Indian-English novel
No full textThe prizewinning author of novels, nonfiction, and hybrid texts, Amitav Ghosh grew up in India and trained as an anthropologist. His works have been translated in over thirty languages. They cross and mix a number of genres, from science fiction to the historical novel, incorporating ethnohistory and travelogue and even recuperating dead languages. His subjects include climate change, postcolonial identities, translocation, migration, oceanic spaces, and the human interface with the environment
Testing protocol to obtain failure properties of asphalt binders at low temperature using creep compliance and stress-controlled strength test
No full textExperimental Investigation of Bio-sealants Used for Pavement Preservation and Development of a New Strength Test for Asphalt Binders at Low Temperature
No full textUniversity of Minnesota Ph.D. dissertation. October 2017. Major: Civil Engineering. Advisor: Mihai Marasteanu. 1 computer file (PDF); xii, 139 pages.Surface treatment using sealants as a mean of pavement preservation is an important tool for cost-effectively extending service life of pavement. Sealants have become an important tool for cost-effectively extending the service life pavements. Due to the combined negative effects of asphalt aging and thermal cracking, it is always more challenging to choose an appropriate preservation technique for pavements built in cold-regions. Asphalt aging and thermal cracking negatively affect pavements built in cold climates. Therefore, it is important to evaluate the effects of sealants in laboratory conditions before application in the field to ensure effective performance. However, preservation activities cannot effectively address major distresses, such as low-temperature cracking, that can occur when the pavement was built from the very beginning with less durable materials. Therefore, an essential requirement to mitigate low-temperature cracking of pavements for asphalt materials used in the construction of pavement built in cold- regions is ensuring proper fracture properties of the asphalt materials used in construction. This study has two parts. In the first part, a laboratory evaluation of the effects of adding bio-sealants to both asphalt binder and mixture is performed. The goal is to obtain relevant properties of treated asphalt materials to understand the mechanism by which sealants improve pavement performance. For asphalt binders, a dynamic shear rheometer and a bending beam rheometer were used to obtain rheological properties of treated and untreated asphalt binders. For asphalt mixtures, field cores from both untreated and treated sections were collected and thin beam specimens were prepared from the cores to compare the creep and strength properties of the field-treated and laboratory-treated mixture. It is observed that the oil-based sealants have a significant softening effect on the control binder compared to the water-based sealant and traditional emulsion. Oil-based sealants increased rutting and fatigue potential of the binder and helped the low-temperature cracking resistance. For asphalt mixtures, different trends are observed for the field samples compared to the laboratory prepared samples. Similar to binder results, significant differences are observed between the asphalt mixtures treated with oil-based and water-based sealants, respectively. Additional analyses were performed to better understand the sealant effects. Fourier transform infrared spectroscopy (FTIR) analysis showed that the sealant products could not be detected in mixture samples collected from the surface of the treated section. Semi-empirical Hirsch model was able to predict asphalt mixture creep stiffness from binder stiffness. The results of a distress survey of the test sections correlated well with the laboratory findings. In the second part, a news binder strength testing method is proposed with the goal to provide an effective tool for selecting asphalt binders that are crack resistant. A modified Bending Beam Rheometer (BBR) is used to perform three-point bending strength tests, at constant loading rate, on asphalt binder beams at low temperature. Based on the results, a protocol for selecting the most crack resistant material from binders with similar rheological properties is proposed.Ghosh, Debaroti. (2017). Experimental Investigation of Bio-sealants Used for Pavement Preservation and Development of a New Strength Test for Asphalt Binders at Low Temperature. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/192677
Investigation of Cracking Resistance of Asphalt Mixtures and Binders
No full textIn this study, the viability of using three test methods for asphalt mixtures and one test method for asphalt
binders are investigated. These test methods are: Bending Beam Rheometer (BBR) for creep and strength of
asphalt mixtures; low temperature Semi Circular Bend (SCB) test for fracture energy of asphalt mixtures; Dynamic
Modulus (E*) test of asphalt mixtures using the Indirect Tensile Test (IDT) configuration; and BBR strength test of
asphalt binders. The materials used in the experimental work were used in MnROAD cells constructed in the
summer of 2016 as part of the MnROAD Cracking Group (CG) experiment, a 3-year pooled-fund project.
The results show that the testing methods investigated provide repeatable results that follow trends similar to
the one observed using traditional methods. The results also show that the properties are highly temperature
dependent and the ranking observed at one temperature can change at a different temperature. In addition, it is
observed that materials with similar rheological properties, such as complex modulus absolute value |E*|, creep
stiffness S, and m-value, do not necessarily have the same fracture resistance. These results confirm one more
time the need for a fracture/strength test for correctly evaluating cracking resistance of asphalt materials.Marasteanu, Mihai; Turos, Mugurel; Ghosh, Debaroti; Matias de Oliveira, Jhenyffer Lorrany; Yan, Tianhao. (2019). Investigation of Cracking Resistance of Asphalt Mixtures and Binders. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/202653
Evaluation of Bio-Fog Sealants for Pavement Preservation
No full textPavement preservation is playing an increasingly significant role in maintaining our aging pavement infrastructure. One important component is the application of sealants to the pavement surface. In a joint study between MnDOT and the University of Minnesota, the field performance and mechanical properties of asphalt mixtures from pavement sections treated with a number of new products, called bio sealants, is investigated. The objective of the study is to obtain relevant properties of treated asphalt materials to understand the mechanism by which sealants improve pavement performance. Laboratory testing was performed on treated asphalt binder and mixtures. For binders, a dynamic shear rheometer and a bending beam rheometer were used to obtain rheological properties of treated and untreated asphalt binders. Field cores from both untreated and treated sections were collected and thin beam specimens were prepared from the cores to compare the creep and strength properties of field-treated and laboratory-treated asphalt mixture. It is observed that the oil-based sealants have a significant softening effect on the control binder compared to the water-based sealants. For asphalt mixtures, different trends are observed for the field samples compared to the laboratory prepared samples. Similar to binder results, significant differences are observed between the asphalt mixtures treated with oil-based and water-based sealants, respectively. From the analysis performed on the bending creep and strength results at low temperature, it is concluded that the application of sealants in the field have no significant effect on these properties. Fourier transform infrared spectroscopy (FTIR) analysis showed that the sealant products could not be detected in mixture samples collected from the surface of the treated section.Ghosh, Debaroti; Turos, Mugur; Marasteanu, Mihai. (2016). Evaluation of Bio-Fog Sealants for Pavement Preservation. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/182435
ENTIRE FUNCTIONS SHARING POLYNOMIALS WITH THEIR DERIVATIVES
No full textIn this paper we study the uniqueness of entire functions sharing two polynomials with their derivatives. The results of the paper improve the corresponding results of Chang and Fang (Kodai Math.J. 25(2002), 309–320) and Lahiri-Ghosh(Present author) (Analysis ,Munich. 31(2011), 47–59)
First person – Arijita Ghosh
No full textABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Arijita Ghosh is the first author on “Leucine-rich repeat-containing 8B protein is associated with the endoplasmic reticulum Ca2+ leak in HEK293 cells”, published in Journal of Cell Science. Arijita is a PhD student in the laboratory of Amal Kanti Bera at the Indian Institute of Technology Madras, Chennai, India, investigating the role of leucine-rich repeat-containing 8 proteins in cellular calcium homeostasis.</jats:p
Understanding Terrorism in the context of Global Security
No full textUnderstanding Terrorism in the context of Global Security
Author / Authors : Shreyasi Ghosh
Page no. 89-106
Discipline : Political Science/Polity/ Democratic studies
Script/language : Roman/English
Category : Research paper
Keywords: Terrorism, Violence, Threat, Global Security, Globalization
Beyond national literatures: Empire and Amitav Ghosh
No full textScholarship on the writer Amitav Ghosh has addressed issues of nationalism, postcolonial identity, ecocriticism, testimony, subalternity, and historiography. But the idea of Ghosh as an Asian American author with a particular relationship to the United States and its national mythologies, has barely been considered. In this essay, I explore this neglected aspect of Ghosh’s œuvre by looking at the idea of America in his writing and by situating his work within what I term "the Bengali American grain". Reading his work alongside that of other Bengali American writers and arguing that it is more ambitious thematically and more anti-imperialistic, I probe Ghosh’s problematic relationship with the United States, asking how his hemispheric writing continues to extend and even alter the terrain often associated with Asian American literature
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