367 research outputs found

    Properties of Sand Cement Brick Containing Quarry Dust (SCBQD) and Bacteria Strain

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    Sand cement brick among favorable building material for low cost house construction due to its low price. Technology development in building material already explored varies waste to be added in improving properties of building materials. Beside that addition of bacteria in building material also proven in literature to improve its properties. In this research addition of bacteria in the cement sand block containing quarry dust (SCBQD) was studied. Several properties namely, compressive strength, depth of carbonation, initial rate of suction (IRS) and water absorption were studied. SCBQD is made from sand, cement, quarry dust and chipping using industrial mix design. In this study, 3% of Enterococcus faecalis (EF) and 5% of Bacillus sp (BSP) bacteria was added in the SCBQD mixes. Three SCBQD mixes were prepared including the control mix without bacteria, SCBQD with 3% EF and SCBQD with 5% BSP. Natural fine aggregate was replaced partially with the quarry dust. 100 mm SCBQD cubes were used to conduct compressive strength, depth of carbonation, initial rate of suction and water absorption test at 7, 14 and 28 days. The experimental results showed that the compressive strength value of SCBQD with addition of bacteria was increased for all curing ages. At 28 days of curing, the compressive strength value for control SCBQD containing quarry without any addition of bacteria is 3.30 MPa, while SCBQD containing quarry dust with addition of 3% of EF bacteria is 3.57 MPa and for SCBQD with 5% of BSP bacteria the value is 4.90 MPa. On the other hand, SCBQD containing 3% EF and 5% BSP gained lower IRS and carbonation depth. Depth of carbonation at 28 days was decreased 9.3% and 20% for SCBQD containing 3% EF and 5% BSP, respectively. Meanwhile, 28-day IRS was reduced 12.9% and 22.6% for SCBQD containing 3% EF and 5% BSP, respectively. In overall, the result shows that, SCBQD with 5% BSP as proven positive and better results when compared to control SCBQD and SCBQD with 3% EF bacteria which is absorb of 12.02% in water absorption. The findings showed that bio-SCBQD containing industrial waste and bacteria has good potential to be used as building material

    Effects of Nonlinear Dispersion Relations on Non-Gaussianities

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    We investigate the effect of non-linear dispersion relations on the bispectrum. In particular, we study the case were the modified relations do not violate the WKB condition at early times, focusing on a particular example which is exactly solvable: the Jacobson-Corley dispersion relation with quartic correction with positive coefficient to the squared linear relation. We find that the corrections to the standard result for the bispectrum are suppressed by a factor H2pc2\frac{H^2}{p_c^2} where pcp_c is the scale where the modification to the dispersion relation becomes relevant. The modification is {\it mildly} configuration-dependent and equilateral configurations are more suppressed with respect to the local ones, by a factor of one percent. There is no configuration leading to enhancements. We then analyze the results in the framework of particle creation using the approximate gluing method of Brandenberger and Martin, which relates more directly to the modeling of the trans-Planckian physics via modifications of the vacuum at a certain cutoff scale. We show that the gluing method overestimates the leading order correction to the spectrum and bispectrum by one and two orders, respectively, in Hpc\frac{H}{p_c}. We discuss the various approximation and conclude that for dispersion relations not violating WKB at early times the particle creation is small and does not lead to enhanced contributions to the bispectrum. We also show that in many cases enhancements do not occur when modeling the trans-Planckian physics via modifications of the vacuum at a certain cutoff scale. Most notably they are only of order O(1) when the Bogolyubov coefficients accounting for particle creation are determined by the Wronskian condition and the minimization of the uncertainty between the field and its conjugate momentum.Comment: v1: 11 pages, 2 figures; v2: references update

    Janus and Multifaced Supersymmetric Theories

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    We investigate the various properties Janus supersymmetric Yang-Mills theories. A novel vacuum structure is found and BPS monopoles and dyons are studied. Less supersymmetric Janus theories found before are derived by a simpler method. In addition, we find the supersymmetric theories when the coupling constant depends on two and three spatial coordinates.Comment: 20 pages, no figures, typos, equations corrected. Additional comment

    Uniqueness of the gauge invariant action for cosmological perturbations

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    In second order perturbation theory different definitions are known of gauge invariant perturbations in single field inflationary models. Consequently the corresponding gauge invariant cubic actions do not have the same form. Here we show that the cubic action for one choice of gauge invariant variables is unique in the following sense: the action for any other, non-linearly related variable can be brought to the same bulk action, plus additional boundary terms. These boundary terms correspond to the choice of hypersurface and generate extra, disconnected contributions to the bispectrum. We also discuss uniqueness of the action with respect to conformal frames. When expressed in terms of the gauge invariant curvature perturbation on uniform field hypersurfaces the action for cosmological perturbations has a unique form, independent of the original Einstein or Jordan frame. Crucial is that the gauge invariant comoving curvature perturbation is frame independent, which makes it extremely helpful in showing the quantum equivalence of the two frames, and therefore in calculating quantum effects in nonminimally coupled theories such as Higss inflation.Comment: 27 page

    Gravitational Wave Spectrum in Inflation with Nonclassical States

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    The initial quantum state during inflation may evolve to a highly squeezed quantum state due to the amplification of the time-dependent parameter, ωphys(k/a)\omega_{phys}(k/a), which may be the modified dispersion relation in trans-Planckian physics. This squeezed quantum state is a nonclassical state that has no counterpart in the classical theory. We have considered the nonclassical states such as squeezed, squeezed coherent, and squeezed thermal states, and calculated the power spectrum of the gravitational wave perturbation when the mode leaves the horizon.Comment: 21 page

    On the dissipative non-minimal braneworld inflation

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    We study the effects of the non-minimal coupling on the dissipative dynamics of the warm inflation in a braneworld setup, where the inflaton field is non-minimally coupled to induced gravity on the warped DGP brane. We study with details the effects of the non-minimal coupling and dissipation on the inflationary dynamics on the normal DGP branch of this scenario in the high-dissipation and high-energy regime. We show that incorporation of the non-minimal coupling in this setup decreases the number of e-folds relative to the minimal case. We also compare our model parameters with recent observational data.Comment: 32 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1001.044

    Ab initio atomistic thermodynamics and statistical mechanics of surface properties and functions

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    Previous and present "academic" research aiming at atomic scale understanding is mainly concerned with the study of individual molecular processes possibly underlying materials science applications. Appealing properties of an individual process are then frequently discussed in terms of their direct importance for the envisioned material function, or reciprocally, the function of materials is somehow believed to be understandable by essentially one prominent elementary process only. What is often overlooked in this approach is that in macroscopic systems of technological relevance typically a large number of distinct atomic scale processes take place. Which of them are decisive for observable system properties and functions is then not only determined by the detailed individual properties of each process alone, but in many, if not most cases also the interplay of all processes, i.e. how they act together, plays a crucial role. For a "predictive materials science modeling with microscopic understanding", a description that treats the statistical interplay of a large number of microscopically well-described elementary processes must therefore be applied. Modern electronic structure theory methods such as DFT have become a standard tool for the accurate description of individual molecular processes. Here, we discuss the present status of emerging methodologies which attempt to achieve a (hopefully seamless) match of DFT with concepts from statistical mechanics or thermodynamics, in order to also address the interplay of the various molecular processes. The new quality of, and the novel insights that can be gained by, such techniques is illustrated by how they allow the description of crystal surfaces in contact with realistic gas-phase environments.Comment: 24 pages including 17 figures, related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

    Observational constraints on Horava-Lifshitz cosmology

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    We use observational data from Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB), along with requirements of Big Bang Nucleosynthesis (BBN), to constrain the cosmological scenarios governed by Horava-Lifshitz gravity. We consider both the detailed and non-detailed balance versions of the gravitational sector, and we include the matter and radiation sectors. We conclude that the detailed-balance scenario cannot be ruled out from the observational point of view, however the corresponding likelihood contours impose tight constraints on the involved parameters. The scenario beyond detailed balance is compatible with observational data, and we present the corresponding stringent constraints and contour-plots of the parameters. Although this analysis indicates that Horava-Lifshitz cosmology can be compatible with observations, it does not enlighten the discussion about its possible conceptual and theoretical problems.Comment: 11 pages, 6 figures, version published in JCA

    The Conformal Transformation in General Single Field Inflation with Non-Minimal Coupling

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    The method of a conformal transformation is applied to a general class of single field inflation models with non-minimal coupling to gravity and non-standard kinetic terms, in order to reduce the cosmological perturbative calculation to the conventional minimal coupling case to all orders in perturbation theory. Our analysis is made simple by the fact that all perturbation variables in the comoving gauge are conformally invariant to all orders. The structure of the vacuum, on which cosmological correlation functions are evaluated, is also discussed. We show how quantization in the Jordan frame for non-minimally coupled inflation models can be equivalently implemented in the Einstein frame. It is thereafter argued that the general N-point cosmological correlation functions (of the curvature perturbation) are independent of the conformal frame.Comment: 15 pages, no figure, references adde
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