675 research outputs found

    Sustainable construction through eco-efficient ultra-high performance concrete

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    An innovative type of steel-fibre reinforced ultra-high performance concrete (UHPC), including its constituent materials and its mixing procedure, is reviewed in this paper. Furthermore, an energy-efficient curing method for developing precast UHPC members is presented as the main goal of the current study. It was found that just with 24 hours of curing in tempered water or steam with 67°C, 95% of 28-day compressive strength in normal curing method, 145 MPa, could be achieved which would be of great interest for prefabrication industry regarding their energy consumption. It also would be beneficial for any project in which early load-bearing capacity is expected. Self-compactness, compressive strength higher than 150 MPa, improved durability and finally low curing energy in precasting phase of the material all offer variety of slim interior and exterior architectural and structural applications even in high-rise structures and aggressive environments where higher strength, ductility and durability is required.(undefined

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    Light scattering by a medium with a spatially modulated optical conductivity: the case of graphene

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    We describe light scattering from a graphene sheet having a modulated optical conductivity. We show that such modulation enables the excitation of surface plasmon-polaritons by an electromagnetic wave impinging at normal incidence. The resulting surface plasmon-polaritons are responsible for a substantial increase of electromagnetic radiation absorption by the graphene sheet. The origin of the modulation can be due either to a periodic strain field or to adatoms (or absorbed molecules) with a modulated adsorption profile.Comment: http://iopscience.iop.org/0953-8984/24/24/24530

    Crossover to the Anomalous Quantum Regime in the Extrinsic Spin Hall Effect of Graphene

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    Recent reports of spin-orbit coupling enhancement in chemically modified graphene have opened doors to studies of the spin Hall effect with massless chiral fermions. Here, we theoretically investigate the interaction and impurity density dependence of the extrinsic spin Hall effect in spin-orbit coupled graphene. We present a nonperturbative quantum diagrammatic calculation of the spin Hall response function in the strong-coupling regime that incorporates skew scattering and anomalous impurity density-independent contributions on equal footing. The spin Hall conductivity dependence on Fermi energy and electron-impurity interaction strength reveals the existence of experimentally accessible regions where anomalous quantum processes dominate. Our findings suggest that spin-orbit-coupled graphene is an ideal model system for probing the competition between semiclassical and bona fide quantum scattering mechanisms underlying the spin Hall effect

    Effect of pozzolanic industrial wastes on durability of engineered cementitious composites (ECC)

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    In this research 26 different compositions of an engineered cementitious composite with different percentages of Fly ash and Silica fume, as two pozzolanic industrial waste and by-product, were mixed. The effect of different percentage of the pozzolans on durability of ECC was studied. To evaluate the durability of the material, two tests, namely water absorption by immersion and water absorption by capillary, were performed. The results from both tests demonstrated the same trend regarding the influence of the wastes on durability. In other words, by increasing the amount of pozzolans, the water absorption after immersion and boiling, decreased more than 50% besides the significant reduction in the rate of absorption by capillary (sorptivity). The results also indicated that silica fume has a higher influence on the water-absorption reduction compared to fly ash however, in the case of absence of silica fume, fly ash plays a significant role on the improvement of durability of the material.info:eu-repo/semantics/publishedVersio

    Management of Maxillofacial Fracture: Experience of Emergency and Trauma Acute Care Surgery Department of Sanglah General Hospital Denpasar Bali

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    BACKGROUND: Maxillofacial fracture is one of the major trauma; the cases were increasing because of the high number of motorcycles in Bali. The goal of the treatment is proper positioning of the occlusion, and it depends on rapid diagnosis and proper treatment. AIM: This study aims to know the characteristics of the maxillofacial fracture patients in Sanglah General Hospital Denpasar Bali. METHODS: A retrospective study, based on medical record were concluded, samples taken in Sanglah General Hospital from January to June 2015. Total recorded patient were 35 patients. The data obtained include age, gender, type of the fractures, and operation management. RESULTS: The injury was more common in male compared to female (80% vs 20%). Age 20 to 40 years old were more common (48.57%), followed by the child to adolescent (aged 0 to 20 years old) were 31.43%, and adult to elderly (aged 40 to 60 years old) was 20%. The mandibular fracture was most common (51.43%), other fractures such as a zygomatic fracture (31.43%) and maxillary fracture (17.14%). Internal fixation was the gold standard of the treatment (65.71%), and the other was an arch bar (34.29%). CONCLUSION: Diagnosing the right injury to the facial bone is a key step in determining a treatment plan. Rapid diagnosis and proper treatment lead to good occlusion, both internal fixation and arch bar were an effective treatment. The importance of dealing with almost all maxillofacial fracture problems in the first surgery

    Critical Delocalization of Chiral Zero Energy Modes in Graphene

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    Graphene subjected to chiral-symmetric disorder is believed to host zero energy modes (ZEMs) resilient to localization, as suggested by the renormalization group analysis of the underlying nonlinear sigma model. We report accurate quantum transport calculations in honeycomb lattices with in excess of 10910^9 sites and fine meV resolutions. The Kubo dc conductivity of ZEMs induced by vacancy defects (chiral BDI class) is found to match 4e2/(πh)4e^2/(\pi h) within 1% accuracy, over a parametrically wide window of energy level broadenings and vacancy concentrations. Our results disclose an unprecedentedly robust metallic regime in graphene, providing strong evidence that the early field-theoretical picture for the BDI class is valid well beyond its controlled weak-coupling regime
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