641 research outputs found

    An evaluation of UV protection imparted by cotton fabrics dyed with natural colorants

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    BACKGROUND: The ultraviolet properties of textiles dyed with synthetic dyes have been widely reported in literature. However, no study has investigated the ultraviolet properties of natural fabrics dyed with natural colorants. This study reports the Ultraviolet Protection Factor (UPF) of cotton fabrics dyed with colorants of plant and insect origins. METHODS: Three cotton fabrics were dyed with three natural colorants. Fabrics were characterized with respect to fabric construction, weight, thickness and thread count. Influence of fabric characteristics on Ultraviolet Protection Factor was studied. Role of colorant concentration on the ultraviolet protection factor was examined via color strength analysis. RESULTS: A positive correlation was observed between the weight of the fabric and their UPF values. Similarly, thicker fabrics offered more protection from ultraviolet rays. Thread count appears to negatively correlate with UPF. Dyeing with natural colorants dramatically increased the protective abilities of all three fabric constructions. Additionally, within the same fabric type UPF values increased with higher depths of shade. CONCLUSION: Dyeing cotton fabrics with natural colorants increases the ultraviolet protective abilities of the fabrics and can be considered as an effective protection against ultraviolet rays. The UPF is further enhanced with colorant of dark hues and with high concentration of the colorant in the fabric

    Recycled household ceramic waste in eco-efficient cement: a case study

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    The ceramic wastes can cause strong damage to the environment. In this article, the experimental study was concentrated on the pozzolanic activity of household ceramic waste and clay bricks waste. The possibility of the partial replacement of Portland cement blended with ceramic waste powder without further heating treatment in different ratios was analyzed. The ceramic waste powder was mixed in samples in various ratios. The evaluation of the ceramic waste powder was performed by grain-size analyses using Laser granulometry, XRD, XRF, Frattini test and strength activity index (SAI) method. The results indicate that the pozzolanic activity of household ceramic waste was higher than that of clay bricks waste. The 15% of HC powder addition could be a possible upper bound for an effective substitution and may also be very cost-efficient for industrial application.The authors acknowledge the National Natural Science Foundation of China: Grant 51578109, and Fundação para a Ciência e a Tecnologia (SFRH/BPD/22680/2005)

    Testosterone metabolism in Neomysis integer following exposure to benzo(a)pyrene

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    Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 144 (2006): 405-412, doi:10.1016/j.cbpb.2006.04.001.Cytochromes P450 (CYPs) are important enzymes involved in the regulation of hormone synthesis and in the detoxification and/or activation of xenobiotics. CYPs are found in virtually all organisms, from archae, and eubacteria to eukaryota. A number of endocrine disruptors are suspected of exerting their effects through disruption of normal CYP function. Consequently, alterations in steroid hormone metabolism through changes in CYP could provide an important tool to evaluate potential effects of endocrine disruptors. The aim of this study was to investigate the potential effects of the known CYP modulator, benzo(a)pyrene (B(a)P), on the testosterone metabolism in the invertebrate Neomysis integer (Crustacea; Mysidacea). N. integer were exposed for 96h to 0.43, 2.39, 28.83, 339.00 and 1682.86μg B(a)P L-1 and a solventcontrol, and subsequently their ability to metabolize testosterone was assessed. Identification and quantification of the produced phase I and phase II testosterone metabolites was performed using liquid chromatography coupled with multiple mass spectrometry (LC-MS2). Significant changes were observed in the overall ability of N. integer to metabolize testosterone when exposed to 2.39, 28.83, 339.00 and 1682.86μg B(a)P L-1 as compared to the control animals.This research was supported by a research grant of the Ghent University Research Fund (BOF, 011.072.02). Dr. Tim Verslycke was supported by a Postdoctoral Fellowship of the Belgian American Educational Foundation

    A numerical investigation on the fire response of a steel girder bridge

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    The response of bridges subject to fire is an under researched topic despite the number of bridge failures caused by fire. Since available data shows that steel girder bridges are especially vulnerable to fire, this paper delves into their fire response by analyzing with a 3D numerical model the response of a typical bridge of 12.20 m span length. A parametric study is performed considering: (1) two possibilities for the axial restraint of the bridge deck, (2) four types of structural steel for the girders (carbon steel and stainless steel grades 1.4301, 1.4401, and 1.4462), (3) three different constitutive models for carbon steel, (4) four live loads, and (5) two alternative fire loads (the hydrocarbon fire defined by Eurocode 1 and a fire corresponding to a real fire event). Results show that restraint to deck expansion coming from an adjacent span or abutment should be considered in the numerical model. In addition, times to collapse are very small when the bridge girders are built with carbon steel (between 8.5 and 18 min) but they can almost double if stainless steel is used for the girders. Therefore, stainless steel is a material to consider for steel girder bridges in a high fire risk situation, especially if the bridge is located in a corrosive environment and its aesthetics deserves special attention. The methodology developed in this paper and the results obtained are useful for researchers and practitioners interested in developing and applying a performance-based approach for the design of bridges against fire. © 2012 Elsevier Ltd. All rights reserved.Funding for this research has been provided to Dr. Paya-Zaforteza by the Spanish Ministry of Education (contract number EX-2008-0669 of the Program for Postdoctoral Stays), the Spanish Ministry of Economy and Competitiveness (research project BIA 2011-27104) and the Universitat Politecnica de Valencia (Research and Development Support Program PAID-06-11). Funding has also been provided to Dr. Maria Garlock by the National Science Foundation (NSF) under award number CMMI-1068252. All opinions expressed in this paper are the authors' and do not necessarily reflect the policies and views of the sponsors.Paya-Zaforteza, I.; Garlock, ME. (2012). A numerical investigation on the fire response of a steel girder bridge. Journal of Constructional Steel Research. 75:93-103. https://doi.org/10.1016/j.jcsr.2012.03.012S931037

    Chapter 6 Site investigation

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    In this chapter we discuss the various phases in site investigation. Phase I investigations are preliminary in nature and are designed to furnish a comprehensive overview of available site information. Phase II investigations consist of site characterization and groundwater monitoring of well installation. Direct methods such as boreholes, piezometers, and geotechnical analysis of soil samples are discussed. While, for indirect methods, we discuss aerial photography, ground penetrating radar, and earth conductivity and resistivity geophysical studies. Furthermore, we discuss issues related to hydrogeochemical investigations. Then, we conclude this chapter with two case studies. The first is related to geoenvironmental investigation at a waste dump site in the United Arab Emirates, while the second is related to the assessment of land salinization in arid lands

    Supplemental Information 4: Raw data.

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    This study evaluated pollution levels in water and sediments of Península de Paraguaná and related these levels with benthic macrofauna along a coastal area where the largest Venezuelan oil refineries have operated over the past 60 years. For this, the concentration of heavy metals, of hydrocarbon compounds and the community structure of the macrobenthos were examined at 20 sites distributed along 40 km of coastline for six consecutive years, which included windy and calm seasons. The spatial variability of organic and inorganic compounds showed considerably high coastal pollution along the study area, across both years and seasons. The southern sites, closest to the refineries, had consistently higher concentrations of heavy metals and organic compounds in water and sediments when compared to those in the north. The benthic community was dominated by polychaetes at all sites, seasons and years, and their abundance and distribution were significantly correlated with physical and chemical characteristics of the sediments. Sites close to the oil refineries were consistently dominated by families known to tolerate xenobiotics, such as Capitellidae and Spionidae. The results from this study highlight the importance of continuing long-term environmental monitoring programs to assess the impact of effluent discharge and spill events from the oil refineries that operate in the western coast of Paraguaná, Venezuela
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