469 research outputs found

    Comparative study between linear-interpolation and stress-block methods of composite design using Cold-Formed Steel section

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    For decades, Hot Rolled Steel (HRS) section was in use in construction of buildings and bridges. The simple reason is that the use of HRS section in composite systems is well established by standard rules and their design necessities as provided in the codes. In this paper, the use of doubly oriented back-to-back Cold-Formed Steel (CFS) section coupled with bolted shear connectors in composite floor system was demonstrated. The bolted system of shear connect or provides an alternative to headed stud shear connector with CFS section as welding of the stud connector is practically not feasible on CFS section because of its thinness nature. The loading system u sed was fourpoint bending test to determine the flexural strength capabilities of the composite floor system. The resulting composite floor system has proven to provide adequate strength and stiffness properties under the applied loads. The results have shown that the theoretical value of flexural capacities calculated agrees reasonably well with the experimental values. In conclusion, the composite floor system can be used in small and medium size buildings, as well as in light weight construction industries

    Thermodynamics of C incorporation on Si(100) from ab initio calculations

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    We study the thermodynamics of C incorporation on Si(100), a system where strain and chemical effects are both important. Our analysis is based on first-principles atomistic calculations to obtain the important lowest energy structures, and a classical effective Hamiltonian which is employed to represent the long-range strain effects and incorporate the thermodynamic aspects. We determine the equilibrium phase diagram in temperature and C chemical potential, which allows us to predict the mesoscopic structure of the system that should be observed under experimentally relevant conditions.Comment: 5 pages, 3 figure

    Behaviour of composite beam arranged as boxed-section with C-channel of cold-formed steel of lipped section

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    Cold formed steel (CFS) of lipped C-Channel sections are commonly use because of their simple forming procedures and easy to erect. To improve the flexural strength of the proposed composite beam, the C-channel of Lipped section is arranged toe-to-toe to form into boxed shape section and filled with self-compacting concrete (SCC). Reinforcement bars was used in a tension zone to increase the flexural strength of the proposed beam in this experimental study. A U-shape re-bars was installed to act as shear connections between concrete slab and beam of boxed section filled with self-compacting concrete. Two specimens were prepared and tested until failure. A C-channel section of size 250mm deep, 75mm width, and 2.4mm thick was used for the proposed composite beam section. Longitudinal rebar's size of 16mm and 20mm were installed at the bottom of the beam encased by the self-compacting concrete of 50MPa. A U-shape re-bar if size 12mm in diameter was used as a shear connector and functioned as vertical shear resistance for the beam system. The beam is kept restrained in position by a profiled metal decking installed on top of the beam to form a slab system also cast using by SCC. The specimens were tested under pure bending arranged as simply supported beams. It was found that the moment resistance of the experimental results agreed well with the predicted numerical analysis

    Thermal characteristics of a residential house in a new township in Johor Bahru

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    As one of the densest population occurred in Johor Bahru, development of a new township become necessary in order to cater this growth. Rapid urbanization is a factor of degradation of environmental quality which may increase surrounded temperature through urban heat island (UHI) phenomena. Therefore, this paper is investigating thermal comfort for a new township, Bandar Dato Onn in Johor Bahru, in order to understand the thermal characteristics of a new township and for further mitigation of UHI phenomena. Surface temperature, ambient temperature and relative humidity have been collected from a terrace house of Bandar Dato Onn. Thermal characteristics with the features of time lag and decrement factors were discussed based on the collected data. The time lag of 5 to 8 hours and the decrement factors of 0.02 to 0.06 were recorded during a five-day measurement. It was concluded that human thermal comfort may not be achieved as the heating, ventilation and air conditioning (HVAC) system needed for bedroom and living room. Passive energy design is suggested to be included in the house in order to have human thermal comfort while reducing the electricity consumption towards sustainable future

    Bending experiment on a novel configuration of composite system using rebar as shear connectors with partially encased cold-formed steel built-up beams

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    In order to achieve greater ductility and strength, as well as to produce a more economical design, a novel composite beam and floor system have been developed to achieve higher strength and ductility, as well as to yield a more economical design purpose. This paper has put focus on this newly developed composite beam system which consists of a profiled metal decking slab made with self-compacting concrete (SCC). It has been joined cold-formed steel (CFS) built-up beams. These beams have been infilled with SCC by means of U-shaped rebar used as shear connectors. The researcher, in order to construct an open section, put together two CFS C-lipped channel sections in a back-to-back formation, and to construct a closed section, the formation was made to be toe-to-toe. The flexural behaviour of the partly encased composite beam was evaluated through experimentation by the researchers. So that the researchers could observe the failure modes and flexural capacity of the construction, a four-point bending test procedure was performed on two samples taking into consideration both closed and open built-up beam sections. The results of the test demonstrated that the open sections were able to exhibit a 24 percent higher ultimate moment capacity as well as greater stiffness and higher vertical deflection. As can be seen from the results of the experimental bending test, the built-up design had a great impact on the capacity and deflection of the section, and the section that was encased was able to reach the ultimate strength when the proposed shear connector was placed in the composite action. In order to validate the present test results, the design and analysis of the new composite beams have been evaluated

    Training a Scoring Function for the Alignment of Small Molecules

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    A comprehensive data set of aligned ligands with highly similar binding pockets from the Protein Data Bank has been built. Based on this data set, a scoring function for recognizing good alignment poses for small molecules has been developed. This function is based on atoms and hydrogen-bond projected features. The concept is simply that atoms and features of a similar type (hydrogen-bond acceptors/donors and hydrophobic) tend to occupy the same space in a binding pocket and atoms of incompatible types often tend to avoid the same space. Comparison with some recently published results of small molecule alignments shows that the current scoring function can lead to performance better than those of several existing methods

    Molecular Epidemiology and Evolution of Human Enterovirus Serotype 68 in Thailand, 2006–2011

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    BACKGROUND: Publications worldwide have reported on the re-occurrence of human enterovirus 68 (EV68), a rarely detected pathogen usually causing respiratory illness. However, epidemiological data regarding this virus in particular on the Asian continent has so far been limited. METHODOLOGY/FINDINGS: We investigated the epidemiology and genetic variability of EV68 infection among Thai children with respiratory illnesses from 2006-2011 (n = 1810). Semi-nested PCR using primer sets for amplification of the 5'-untranslated region through VP2 was performed for rhino-enterovirus detection. Altogether, 25 cases were confirmed as EV68 infection indicating a prevalence of 1.4% in the entire study population. Interestingly, the majority of samples were children aged >5 years (64%). Also, co-infection with other viruses was found in 28%, while pandemic H1N1 influenza/2009 virus was the most common co-infection. Of EV68-positive patients, 36% required hospitalizations with the common clinical presentations of fever, cough, dyspnea, and wheezing. The present study has shown that EV68 was extremely rare until 2009 (0.9%). An increasing annual prevalence was found in 2010 (1.6%) with the highest detection frequency in 2011 (4.3%). Based on analysis of the VP1 gene, the evolutionary rate of EV68 was estimated at 4.93 × 10(-3) substitutions/site/year. Major bifurcation of the currently circulating EV68 strains occurred 66 years ago (1945.31 with (1925.95-1960.46)95% HPD). Among the current lineages, 3 clusters of EV68 were categorized based on the different molecular signatures in the BC and DE loops of VP1 combined with high posterior probability values. Each cluster has branched off from their common ancestor at least 36 years ago (1975.78 with (1946.13-1984.97)95% HPD). CONCLUSION: Differences in epidemiological characteristic and seasonal profile of EV68 have been found in this study. Results from Bayesian phylogenetic investigations also revealed that EV68 should be recognized as a genetically diverse virus with a substitution rate identical to that of enterovirus 71 genotype B (4.2 × 10(-3 )s/s/y)

    Family-focused contextual factors associated with lifestyle patterns in young children from two mother-offspring cohorts : GUSTO and EDEN

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    Background Integrated patterns of energy balance-related behaviours of preschool children in Asia are sparse, with few comparative analyses. Purpose Using cohorts in Singapore (GUSTO) and France (EDEN), we characterized lifestyle patterns of children and investigated their associations with family-focused contextual factors. Methods Ten behavioural variables related to child's diet, walking, outdoor play and screen time were ascertained by parental questionnaires at age 5-6 years. Using principal component analysis, sex-specific lifestyle patterns were derived independently for 630 GUSTO and 989 EDEN children. Contextual variables were organised into distal (family socio-economics, demographics), intermediate (parental health, lifestyle habits) and proximal (parent-child interaction factors) levels of influence and analysed with hierarchical linear regression. Results Three broadly similar lifestyle patterns were identified in both cohorts: "discretionary consumption and high screen time", "fruit, vegetables, and low screen time" and "high outdoor playtime and walking". The latter two patterns showed small differences between cohorts and sexes. The "discretionary consumption and high screen time" pattern was consistently similar in both cohorts; distal associated factors were lower maternal education (EDEN boys), no younger siblings (GUSTO boys) and Malay/Indian ethnicity (GUSTO), while intermediate and proximal associated factors in both cohorts and sexes were poor maternal diets during pregnancy, parents allowing high child control over food intake, snacking between meals and having television on while eating. Conclusions Three similar lifestyle patterns were observed among preschool children in Singapore and France. There were more common associated proximal factors than distal ones. Cohort specific family-focused contextual factors likely reflect differences in social and cultural settings. Findings will aid development of strategies to improve child health.Peer reviewe

    Impact of nutraceuticals on markers of systemic inflammation: Potential relevance to cardiovascular diseases – A position paper from the International Lipid Expert Panel (ILEP)

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    Inflammation is a marker of arterial disease stemming from cholesterol-dependent to -independent molecular mechanisms. In recent years, the role of inflammation in atherogenesis has been underpinned by pharmacological approaches targeting systemic inflammation that have led to a significant reduction in cardiovascular disease (CVD) risk. Although the use of nutraceuticals to prevent CVD has largely focused on lipid-lowering (e.g, red-yeast rice and omega-3 fatty acids), there is growing interest and need, especially now in the time of coronavirus pandemic, in the use of nutraceuticals to reduce inflammatory markers, and potentially the inflammatory CVD burden, however, there is still not enough evidence to confirm this. Indeed, diet is an important lifestyle determinant of health and can influence both systemic and vascular inflammation, to varying extents, according to the individual nutraceutical constituents. Thus, the aim of this Position Paper is to provide the first attempt at recommendations on the use of nutraceuticals with effective anti-inflammatory properties
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