Effects of Variable Newton Constant During Inflation

In this paper the effects of time-dependent Newton constant G during inflation are studied. We present the formalism of curvature perturbations in an inflationary system with a time-dependent Newton constant. As an example we consider a toy model in which G undergoes a sudden change during inflation. By imposing the appropriate matching conditions the imprints of this sharp change in G on curvature perturbation power spectrum are studied. We show that if G increases (decreases) during the transition the amplitude of curvature perturbations on large scales decreases (increases). In our model with a sudden change in G a continuous sinusoidal modulations on curvature power spectrum is induced. However, in a realistic scenario in which the change in G has some finite time scale we expect these sinusoidal modulations to be damped on short scales. The generated features may be used to explain the observed glitches on CMB power spectrum. This puts a bound on $\Delta G$ during inflation of roughly the same order as current bounds on $\Delta G$ during the entire observed age of the universe.Comment: 15 pages, 2 figures. Typos fixed, new references added, conforms with the journal versio

Boltzmann brains and the scale-factor cutoff measure of the multiverse

To make predictions for an eternally inflating "multiverse", one must adopt a procedure for regulating its divergent spacetime volume. Recently, a new test of such spacetime measures has emerged: normal observers - who evolve in pocket universes cooling from hot big bang conditions - must not be vastly outnumbered by "Boltzmann brains" - freak observers that pop in and out of existence as a result of rare quantum fluctuations. If the Boltzmann brains prevail, then a randomly chosen observer would be overwhelmingly likely to be surrounded by an empty world, where all but vacuum energy has redshifted away, rather than the rich structure that we observe. Using the scale-factor cutoff measure, we calculate the ratio of Boltzmann brains to normal observers. We find the ratio to be finite, and give an expression for it in terms of Boltzmann brain nucleation rates and vacuum decay rates. We discuss the conditions that these rates must obey for the ratio to be acceptable, and we discuss estimates of the rates under a variety of assumptions.Comment: 32 pp, 2 figs. Modified to conform to the version accepted by Phys. Rev. D. The last paragraph of Sec. V-A, about Boltzmann brains in Minkowski space, has been significantly enlarged. Two sentences were added to the introduction concerning the classical approximation and the hope of finding a motivating principle for the measure. Several references were adde

Measure Problem for Eternal and Non-Eternal Inflation

We study various probability measures for eternal inflation by applying their regularization prescriptions to models where inflation is not eternal. For simplicity we work with a toy model describing inflation that can interpolate between eternal and non-eternal inflation by continuous variation of a parameter. We investigate whether the predictions of four different measures (proper time, scale factor cutoff, stationary and causal {diamond}) change continuously with the change of this parameter. We will show that {only} for the stationary measure the predictions change continuously. For the proper-time and the scale factor cutoff, the predictions are strongly discontinuous. For the causal diamond measure, the predictions are continuous only if the stage of the slow-roll inflation is sufficiently long.Comment: 9 pages, 4 figure

Sustainable Supplier Selection in Construction Industry through Hybrid Fuzzy-Based Approaches

Due to increase in the public and stakeholders’ awareness regarding economic, environmental, and social issues, the construction industry tends to follow the sustainability policies and practices in supply chain management. Hence, one of the most crucial aspects for a construction company in this regard is sustainable supplier selection, and, to this end, an accurate and reliable model is required. In this paper a hybrid fuzzy best-worst method and fuzzy inference system model is developed for sustainable supplier selection. In the first phase of this study, after determining 19 criteria in three main aspects, the final weight of each aspect and criterion is obtained using fuzzy best-worst method approach. In the second phase, the most sustainable supplier is selected by running the weighted fuzzy inference system both in aspect and criterion level, providing more accurate results compared to the use of other available models. Finally, two different tests are employed to validate the results and evaluate the robustness of the proposed model. The novel developed model enables the decision-maker to simulate the decision-making process, reduce the calculations loads, consider a large number of criteria in decision making, and resolve the inherited uncertainties in experts’ responses

The pore-network modeling of gas-condensate flow: Elucidating the effect of pore morphology, wettability, interfacial tension, and flow rate

The gas-condensate flow in the near-well region is significantly influenced by phase behavior, flow regimes, and pore geometries. In conventional gas-condensate reservoirs the key pore-scale parameters affecting gas and condensate relative permeabilities include velocity (i.e., pressure gradient), interfacial tension (IFT), wettability, and pore structure. To examine the impact of these parameters, three-dimensional (3D) and two-dimensional (2D) pore-network models (PNMs) were developed. A proposed compositional model was used to implement the cyclic process of condensate corner flow (film flow for circular tubes) and condensate blockage. Response surface methodology (RSM) was employed to achieve high accuracy in phase equilibrium calculations and to enhance computational speed. The 3D PNM simulations of gas-condensate core-flood experiments confirmed the consistency and accuracy of the implemented methodology. A parametric study of governing factors such as pore shapes, wettability, IFT, and flow rate was conducted using the developed PNMs. The findings revealed that pore geometry and contact angle dictate the condensate meniscus curvature and snap-off process in pore throats. The unblocking of throats by condensate bridges was primarily controlled by contact angle, IFT, and pore cross-section. A shift to neutral wetting substantially improved gas-condensate flow in higher IFTs and angular pore shapes. The positive velocity effect on low-IFT gas-condensate flow, known as the coupling rate effect, was more pronounced in simulations with lower contact angles, and its impact was negligible at neutral wettability, similar to the IFT effect. The simulation results and findings underscore the influence of each factor and offer a method for incorporating the effects of pore shape (i.e., formation type and structure), contact angle, velocity, and IFT in continuum scale simulations

Barriers to green roof installation: an integrated fuzzy-based MCDM approach

Despite its environmental and financial benefits for public and private sectors, adoption of the green roof (GR) system comprises barriers that have inhibited its application in Malaysia. Studies on the barriers to GR installation have been conducted worldwide; however, they are scarce in Malaysia. Moreover, in the literature, conventional methods are used for prioritizing the barriers, while the barriers to GR adoption are not differentiated among its types. In view of this argument, this paper identifies and prioritizes the barriers to GR installation using Fuzzy Delphi Method (FDM) and Fuzzy Best-Worst Method (FBWM), respectively. Of 20 identified barriers, six (for intensive GR) and nine (for extensive GR) were rejected using FDM, while the selected barriers were prioritized using FBWM. The findings reveal that “high initial cost” and “lack of awareness and knowledge” barriers to IGR and EGR installation are the most significant, respectively; while “challenges of installation” and “structural damage” are the least significant for both types of GRs. A comparative analysis was conducted to show the outperformance of used methods while the validity of the results was checked through case studies. The clear message of the results addresses the amalgamation of legislative enforcements with financial incentives and emphasis on the improvement of knowledge and awareness, which will ultimately lead to effective and widespread implementation of GR systems. The study provides practical guidelines for the stakeholders at the forefront by enabling them to grapple with the most significant barriers to GR installation

Olivier Devaux. La pique et la plume : enseignement à Toulouse pendant la Révolution. Préface de Jacques GODECHOT. Toulouse : Eché-Editions universitaires du Sud, 1988. In-8°, 182 pages, 4 planches ; Olivier Devaux. L'enseignement à Toulouse sous le Consulat et l'Empire. Toulouse : Presses de l'Institut d'études politiques de Toulouse ; Centre d'histoire contemporaine des institutions, 1990. In-8°, VI-292 pages ; Olivier Devaux. L'enseignement à Toulouse sous la Restauration. Toulouse : Presses de l'Université des sciences sociales de Toulouse, 1994. In-8°, 224 pages.

Olivier Devaux. La pique et la plume : enseignement à Toulouse pendant la Révolution. Préface de Jacques GODECHOT. Toulouse : Eché-Editions universitaires du Sud, 1988. In-8°, 182 pages, 4 planches ; Olivier Devaux. L'enseignement à Toulouse sous le Consulat et l'Empire. Toulouse : Presses de l'Institut d'études politiques de Toulouse ; Centre d'histoire contemporaine des institutions, 1990. In-8°, VI-292 pages ; Olivier Devaux. L'enseignement à Toulouse sous la Restauration. Toulouse : Presses de l'Université des sciences sociales de Toulouse, 1994. In-8°, 224 pages.. In: Bibliothèque de l'école des chartes. 1995, tome 153, livraison 2. pp. 525-528

A Monte Carlo technique in safety assessment of slope under seismic condition

In geotechnical engineering, stabilization of slopes is one of the significant issues that needs to be considered especially in seismic situation. Evaluation and precise prediction of factor of safety (FOS) of slopes can be useful for designing/analyzing very important structures such as dams and highways. Hence, in the present study, an attempt has been done to evaluate/predict FOS of many homogenous slopes in different conditions using Monte Carlo (MC) simulation technique. For achieving this aim, the most important parameters on the FOS were investigated, and finally, slope height (H), slope angle (α), cohesion (C), angle of internal friction (∅) and peak ground acceleration (PGA) were selected as model inputs to estimate FOS values. In the first step of analysis, a multiple linear regression (MLR) equation was developed and then it was used for evaluation and prediction by MC technique. Generally, MC model simulated FOS of less than 1.18, lower and higher than measured and predicted FOS values, respectively. However, the results of MC simulation for the FOS values of more than 1.33, is higher than those measured and predicted FOS values. As a result, the mean of FOS values simulated by MC was very close to the mean of actual FOS values. Moreover, results of sensitivity analysis demonstrated that the (∅), among other parameters, is the most effective one on FOS. The obtained results indicated that MC is a reliable approach for evaluating and estimating FOS of slopes with high degree of performance