211 research outputs found

    Characterization of LUSI Mud as Geopolymer Raw Material

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    The mud of mud volcano samples were collected from an eruption site named ‘LUSI’ (Lumpur “mud” –Sidoarjo), East Java, Indonesia for characterization. Analysis showed that, the major constituents of mud are SiO2 and Al2O3 which are higher than those in fly ash. The particle of mud has a flake-shaped particle and the overall particle size is dominated by particles between 2.5μm – 25.0μm. The results of XRD shows that mud of mud volcano have a characteristic of structurally disordered compounds, and a set of peaks corresponding to minor crystalline phases such as quartz, feldspars, and kaolinite. FTIR adsorption bands of the raw material of mud have the chemical bonding between bands 1-5

    The Early Iron Age collective tomb LCG-1 at Dibba al-Bayah, Oman: long-distance exchange and cross-cultural interaction

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    The Iron Age (c. 1300-600 BC) of South-eastern Arabia is characterised by rapid expansion of settlement. Social structures formed over the previous millennia, however, persisted and were reinforced through the development of collective funerary monuments. A recently discovered tomb of Late Bronze to Early Iron Age date at Dibba al-Bayah in the Sultanate of Oman has yielded a range of artefacts that illuminate the nature and extent of the long-distance contacts of the local community. Seemingly selected not only for their exotic appeal, but also for their apotropaic function, these objects testify to a deep cross-cultural knowledge extending across the wider region during this crucial period in Arabian prehistory

    Geology and rural landscapes in central Spain (Guadalajara, Castilla—La Mancha)

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    Methods commonly used in regional geological analysis were employed to study the visual landscapes of the Sigüenza–Molina de Aragón area (Spain). Landscape data were compiled to produce a landscape map and a photograph catalogue. Lithological composition, tectonic structure and recent erosive processes are the main factors controlling the visual landscapes. Territorial properties, such as colours and agricultural capacities, are controlled by these geological characteristics. The landscape map and the photographic catalogue is the main contribution of this paper. The first level of landscape classification distinguishes zones with dominance of either flat, concave or convex areas. Other parts of the territory are, however, composed of concave and convex combinations that originate hybrid orographic structures. In a second level of classification, several subdivisions for each of these types are established

    The Extracellular Matrix Component Psl Provides Fast-Acting Antibiotic Defense in Pseudomonas aeruginosa Biofilms

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    Bacteria within biofilms secrete and surround themselves with an extracellular matrix, which serves as a first line of defense against antibiotic attack. Polysaccharides constitute major elements of the biofilm matrix and are implied in surface adhesion and biofilm organization, but their contributions to the resistance properties of biofilms remain largely elusive. Using a combination of static and continuous-flow biofilm experiments we show that Psl, one major polysaccharide in the Pseudomonas aeruginosa biofilm matrix, provides a generic first line of defense toward antibiotics with diverse biochemical properties during the initial stages of biofilm development. Furthermore, we show with mixed-strain experiments that antibiotic-sensitive “non-producing” cells lacking Psl can gain tolerance by integrating into Psl-containing biofilms. However, non-producers dilute the protective capacity of the matrix and hence, excessive incorporation can result in the collapse of resistance of the entire community. Our data also reveal that Psl mediated protection is extendible to E. coli and S. aureus in co-culture biofilms. Together, our study shows that Psl represents a critical first bottleneck to the antibiotic attack of a biofilm community early in biofilm development.National Institutes of Health (U.S.). National Institute of Environmental Health Sciences (Training Grant in Toxicology 5 T32 ES7020-37

    A novel approach to approximate fractional derivative with uncertain conditions

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    This paper focuses on providing a new scheme to find the fuzzy approximate solution of fractional differential equations (FDEs) under uncertainty. The Caputo-type derivative base on the generalized Hukuhara differentiability is approximated by a linearization formula to reduce the corresponding uncertain FDE to an ODE under fuzzy concept. This new approach may positively affect on the computational cost and easily apply for the other types of uncertain fractional-order differential equation. The performed numerical simulations verify the proficiency of the presented scheme

    Clostridium difficile in Ready-to-Eat Salads, Scotland

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    Of 40 ready-to-eat salads, 3 (7.5%) were positive for Clostridium difficile by PCR. Two isolates were PCR ribotype 017 (toxin A–, B+), and 1 was PCR ribotype 001. Isolates were susceptible to vancomycin and metronidazole but variably resistant to other antimicrobial drugs. Ready-to-eat salads may be potential sources for virulent C. difficile

    Structural modifications of superficial layer of C45 steel samples through WT20 and WZr8 depositions

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    Link to publisher's homepage at https://iopscience.iop.org/The paper presents technological aspects regarding the modification of mechanical chracteristics in the superficial layer of C45 steel samples, through thin layers deposition using WT20 and WZr8 electrodes. Deposition of thin layers was made through electrical discharge method in impulse. The obtained samples were microstructural analyzed, at various magnitudes, on an VegaTescan electronic microscope. Also, measurements of mechanical chracteristics were made through indentation, highlighting the improved values after layers deposition with the 2 electrods

    1st International Conference on Sustainable Materials 2007 (ICoSM2007)

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    Organized by Universiti Malaysia Perlis (UniMAP), 9th - 12th June 2007 at Park Royal Hotel, Penang.This research will attempt to use rubber waste (tire rubber) replacement of coarse aggregate to produce early age concrete. An experiment will carry out to determine the strength of early age concrete with rubber waste coarse aggregate to compare with the rubber waste as filler in concrete (with crushed stone coarse aggregate and sand fine aggregate).This research will carry out 2 difference type of concrete which are rubberized concrete and rubber filler in concrete. In rubberized concrete, rubbers were used to replace coarse aggregates and river sand as fine aggregate. Furthermore, in rubber filler in concrete, crushed stone was used as coarse aggregate and river sand as fine aggregate. Coarse aggregate usually gravel or crushed stone and shredded rubber as filler in concrete. The design strength of mixture concrete is 15 MPa for 7 days and water cement ratio are 0.4, 0.5, and 0.7. Lastly; the compression cube test will be test on 7 days. The properties of the aggregate will compared

    Correlation of the processing parameters in the formation of granulated ground blast furnace slag geopolymer

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    Link to publisher's homepage at https://iopscience.iop.org/Geopolymers are inorganic materials with huge potential applications including building material, fire resistant materials, and agricultural construction materials. Various parameters influenced the final properties of these geopolymer concretes. This study developed the effects of several factors such as solid-to-liquid ratio, NaOH concentration, and Na2SiO3/NaOH ratio on the compressive strength of granulated ground blast furnace slag (GGBFS) by statistical design of experiment (DOE) approach. Analysis of the experimental results through ANOVA exhibited that the specimen with NaOH concentration of 10M, Na2SiO3/NaOH ratio equals to 2.5, and solid-to-liquid ratio of 3.0 curing at room temperatures for 28 days was potential of highest strength (168.705 MPa) in the considered procedure. Besides, the relationship between compressive strength and influential factors could be suitably by fraction factorial design method
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