155 research outputs found

    DEVELOPMENT OF A STATISTICALLY-BASED METHODOLOGY FOR ANALYZING AUTOMATIC SAFETY TREATMENTS AT ISOLATED HIGH-SPEED SIGNALIZED INTERSECTIONS

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    Crashes at isolated rural intersections, particularly those involving vehicles traveling perpendicularly to each other, are especially dangerous due to the high speeds involved. Consequently, transportation agencies are interested in reducing the occurrence of this crash type. Many engineering treatments exist to improve safety at isolated, high-speed, signalized intersections. Intuitively, it is critical to know which safety treatments are the most effective for a given set of selection criteria at a particular intersection. Without a well-defined decision making methodology, it is difficult to decide which safety countermeasure, or set of countermeasures, is the best option. Additionally, because of the large number of possible intersection configurations, traffic volumes, and vehicle types, it would be impossible to develop a set of guidelines that could be applied to all signalized intersections. Therefore, a methodology was developed in in this paper whereby common countermeasures could be modeled and analyzed prior to being implemented in the field. Due to the dynamic and stochastic nature of the problem, the choice was made to employ microsimulation tools, such as VISSIM, to analyze the studied countermeasures. A calibrated and validated microsimulation model of a signalized intersection was used to model two common safety countermeasures. The methodology was demonstrated on a test site located just outside of Lincoln, Nebraska. The model was calibrated to the distribution of observed speeds collected at the test site. It was concluded that the methodology could be used for the preliminary analysis of safety treatments based on select safety and operational measures of effectiveness

    The effect of organic acids as leaching agents for hydrometallurgical recovery of metals from PCBs

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    The hydrometallurgical treatment, compared to other recycling processes, is of great interest due to its higher efficiency and better economy. In hydrometallurgy, popular agents used in the leaching processes of e-waste include inorganic acids, ammonia, chlorides, thiourea, thiosulphates. Organic acids are also becoming more and more popular. The article presents an overview of possible paths of the metal recovery from e-waste with the use of various organic acids. The results of own research on the leaching of printed circuit boards with the use of organic acids including citric acid, oxalic acid, acetic acid, formic acid, malic acid, lactic acid are also presented

    The effect of organic acids as leaching agents for hydrometallurgical recovery of metals from PCBs

    Get PDF
    The hydrometallurgical treatment, compared to other recycling processes, is of great interest due to its higher efficiency and better economy. In hydrometallurgy, popular agents used in the leaching processes of e-waste include inorganic acids, ammonia, chlorides, thiourea, thiosulphates. Organic acids are also becoming more and more popular. The article presents an overview of possible paths of the metal recovery from e-waste with the use of various organic acids. The results of own research on the leaching of printed circuit boards with the use of organic acids including citric acid, oxalic acid, acetic acid, formic acid, malic acid, lactic acid are also presented

    The effect of organic acids as leaching agents for hydrometallurgical recovery of metals from PCBs

    Get PDF
    The hydrometallurgical treatment, compared to other recycling processes, is of great interest due to its higher efficiency and better economy. In hydrometallurgy, popular agents used in the leaching processes of e-waste include inorganic acids, ammonia, chlorides, thiourea, thiosulphates. Organic acids are also becoming more and more popular. The article presents an overview of possible paths of the metal recovery from e-waste with the use of various organic acids. The results of own research on the leaching of printed circuit boards with the use of organic acids including citric acid, oxalic acid, acetic acid, formic acid, malic acid, lactic acid are also presented.Web of Science613-461260

    The Epigravettian chronology and the human population of eastern Central Europe during MIS2

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    The goal of this paper is to refine the relative and absolute chronology of Epigravettian culture (26.5-15.0 ka) in eastern Central Europe (ECE) and clarify its relation to the Last Glacial Maximum (LGM) and subsequent climatic changes. Epigravettian sites were sorted into three chronological clusters: initial LGM (ILGM) (26.5-24.0 ka), local LGM (LLGM) (24.0-20.0 ka), and post-LGM (PLGM) (20.0-14.7 ka). We obtained new radiocarbon dates from previously dated and undated sites, then analysed the lithic tool typology and faunal data to seek correlations between age and archaeological features.The lithic typology study did not find differences between ILGM and LLGM sites, but the tool type variance between LLGM and PLGM was significant, applicable for relative chronology. ILGM and LLGM lithic assemblages were characterized by domestic tool dominance and the frequent use of flake tools. PLGM assemblages were correlated with armature dominance and blade/let tools. Among the armatures, backed point variants characterized the PLGM sites compared to the ILGM and LLGM. The sole ILGM lithic armature was the retouched blade/let point. The LLGM also possessed this type and often included backed blade/lets.ILGM faunal data, although few, implied the hunting of mammoth and reindeer. The LLGM data represented recurring hunting of reindeer and horse, and PLGM data indicated the hunting of horse, reindeer, and mammoth.Our results suggested that the territory of Poland was deserted by humans in the LLGM. Moravia and Lower Austria was inhabited until the first half of the LLGM, while the Carpathian Basin was all along the ILGM. The preference for the Carpathian Basin could have been the milder climate, the abundance of fauna, and permanent access to tree vegetation. After the LGM the glacial flora and fauna gradually disappeared, leading to a reduced human presence in southern ECE. Thus, the disappearance of the Epigravettian culture and Pleistocene hunter-gatherer occupations are linked to the amelioration of climate that resulted in the disappearance of the Pleistocene environment. (C) 2021 The Authors. Published by Elsevier Ltd.Human Origin

    Titanium dioxide nanoparticles exacerbate DSS-induced colitis: role of the NLRP3 inflammasome

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    OBJECTIVE: Western lifestyle and diet are major environmental factors playing a role in the development of IBD. Titanium dioxide (TiO2) nanoparticles are widely used as food additives or in pharmaceutical formulations and are consumed by millions of people on a daily basis. We investigated the effects of TiO2 in the development of colitis and the role of the nucleotide-binding oligomerisation domain receptor, pyrin domain containing (NLRP)3 inflammasome. DESIGN: Wild-type and NLRP3-deficient mice with dextran sodium sulfate-induced colitis were orally administered with TiO2 nanoparticles. The proinflammatory effects of TiO2 particles in cultured human intestinal epithelial cells (IECs) and macrophages were also studied, as well as the ability of TiO2 crystals to traverse IEC monolayers and accumulate in the blood of patients with IBD using inductively coupled plasma mass spectrometry. RESULTS: Oral administration of TiO2 nanoparticles worsened acute colitis through a mechanism involving the NLRP3 inflammasome. Importantly, crystals were found to accumulate in spleen of TiO2-administered mice. In vitro, TiO2 particles were taken up by IECs and macrophages and triggered NLRP3-ASC-caspase-1 assembly, caspase-1 cleavage and the release of NLRP3-associated interleukin (IL)-1β and IL-18. TiO2 also induced reactive oxygen species generation and increased epithelial permeability in IEC monolayers. Increased levels of titanium were found in blood of patients with UC having active disease. CONCLUSION: These findings indicate that individuals with a defective intestinal barrier function and pre-existing inflammatory condition, such as IBD, might be negatively impacted by the use of TiO2 nanoparticles

    An in vivo screen identifies ependymoma oncogenes and tumor-suppressor genes

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    Cancers are characterized by non-random chromosome copy number alterations that presumably contain oncogenes and tumor-suppressor genes (TSGs). The affected loci are often large, making it difficult to pinpoint which genes are driving the cancer. Here we report a cross-species in vivo screen of 84 candidate oncogenes and 39 candidate TSGs, located within 28 recurrent chromosomal alterations in ependymoma. Through a series of mouse models, we validate eight new ependymoma oncogenes and ten new ependymoma TSGs that converge on a small number of cell functions, including vesicle trafficking, DNA modification and cholesterol biosynthesis, identifying these as potential new therapeutic targets.We are grateful to F.B. Gertler (Massachusetts Institute of Technology) and S. Gupton (University of North Carolina) for the generous gift of the VAMP7-phlorin construct and the staffs of the Hartwell Center for Bioinformatics and Biotechnology, the Small Animal Imaging Center, the Animal Resources Center, the Cell and Tissue Imaging Center, and the Flow Cytometry and Cell Sorting Shared Resource at St. Jude Children's Research Hospital for technical assistance. This work was supported by grants from the US National Institutes of Health (R01CA129541, P01CA96832 and P30CA021765, R.J.G.), by the Collaborative Ependymoma Research Network (CERN) and by the American Lebanese Syrian Associated Charities (ALSAC)

    Structure and lithology of the Japan Trench subduction plate boundary fault

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    The 2011 Mw9.0 Tohoku-oki earthquake ruptured to the trench with maximum coseismic slip located on the shallow portion of the plate boundary fault. To investigate the conditions and physical processes that promoted slip to the trench, Integrated Ocean Drilling Program Expedition 343/343T sailed 1 year after the earthquake and drilled into the plate boundary ∼7 km landward of the trench, in the region of maximum slip. Core analyses show that the plate boundary décollement is localized onto an interval of smectite-rich, pelagic clay. Subsidiary structures are present in both the upper and lower plates, which define a fault zone ∼5–15m thick. Fault rocks recovered from within the clay-rich interval contain a pervasive scaly fabric defined by anastomosing, polished, and lineated surfaces with two predominant orientations. The scaly fabric is crosscut in several places by discrete contacts across which the scaly fabric is truncated and rotated, or different rocks are juxtaposed. These contacts are inferred to be faults. The plate boundary décollement therefore contains structures resulting from both distributed and localized deformation. We infer that the formation of both of these types of structures is controlled by the frictional properties of the clay: the distributed scaly fabric formed at low strain rates associated with velocity-strengthening frictional behavior, and the localized faults formed at high strain rates characterized by velocity-weakening behavior. The presence of multiple discrete faults resulting from seismic slip within the décollement suggests that rupture to the trench may be characteristic of this margin
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