Non-linear seismic analysis of RC structures with energy-dissipating devices

The poor performance of some reinforced concrete (RC) structures during strong earthquakes has alerted about the need of improving their seismic behavior, especially when they are designed according to obsolete codes and show low structural damping, important second-order effects and low ductility, among other defects. These characteristics allow proposing the use of energy-dissipating devices for improving their seismic behavior. In this work, the non-linear dynamic response of RC buildings with energy dissipators is studied using advanced computational techniques. A fully geometric and constitutive non-linear model for the description of the dynamic behavior of framed structures is developed. The model is based on the geometrically exact formulation for beams in finite deformation. Points on the cross section are composed of several simple materials. The mixing theory is used to treat the resulting composite. A specific type of element is proposed for modeling the dissipators including the corresponding constitutive relations. Special attention is paid to the development of local and global damage indices for describing the performance of the buildings. Finally, numerical tests are presented for validating the ability of the model for reproducing the non-linear seismic response of buildings with dissipators

Ineslatic analysis of geometrically exact rods

In this work, a formulation for rod structures, able to consider coupled geometric and constitutive sources of nonlinearity in both the static and the dynamic range, is developed. It is extended for allowing the inclusion of passive energy dissipating elements as a special rod element and geometric irregularities as a full three-dimensional body connected to the framed structure by means of a two-scale model. The proposed formulation is based on the Reissner-Simo geometrically exact formulation for rods considering an initially curved reference configuration and extended to include arbitrary distribution of composite materials in the cross sections. Each material point of the cross section is assumed to be composed of several simple materials with their own thermodynamically consistent constitutive laws. The simple mixing rule is used for treating the resulting composite. Cross sections are meshed into a grid of quadrilaterals, each of them corresponding to a fiber directed along the axis of the beam. A mesh independent response is obtained by means of the regularization of the energy dissipated at constitutive level considering the characteristic length of the mesh and the fracture energy of the materials. Local and global damage indices have been developed based on the ratio between the visco-elastic and nonlinear stresses. The consistent linearization of the weak form of the momentum balance equations is performed considering the effects of rate dependent inelasticity. Due to the fact that the deformation map belongs to a nonlinear manifold, an appropriated version of Newmark's scheme and of the iterative updating procedure of the involved variables is developed. The space discretization of the linearized problem is performed using the standard Galerkin finite element approach. A Newton-Raphson type of iterative scheme is used for the step-by-step solution of the discrete problem. A specific element for energy dissipating devices is developed, based on the rod model but releasing the rotational degrees of freedom. Appropriated constitutive relations are given for a wide variety of possible dissipative mechanisms. Several numerical examples have been included for the validation of the proposed formulation. The examples include elastic and inelastic finite deformation response of framed structures with initially straight and curved beams. Comparisons with existing literature is performed for the case of plasticity and new results are presented for degrading and composite materials. Those examples show how the present formulation is able to capture different complex mechanical phenomena such as the uncoupling of the dynamic response from resonance due to inelastic incursions and suppression of the high frequency content. The study of realistic flexible pre-cast and cast in place reinforced concrete framed structures subjected to static and dynamic actions is also carried out. Detailed studies regarding to the evolution of local damage indices, energy dissipation and ductility demands are presented. The studies include the seismic response of concrete structures with energy dissipating devices. Advantages of the use of passive control are verified

Volatility spillover effect of pan-Asia’s property portfolio markets

This study assesses the spillover effect of the listed property companies that cover pan-Asian countries, namely Malaysia, Thailand, Indonesia, Singapore, Vietnam, South Korea, Japan, China, the Philippines, and Hong Kong. The impact of market integration will create a spillover effect to the countries’ economic performances, in particular the property market. As macroeconomic factors have high correlation with the performance of property security markets, it is therefore important to study the spillover effect by integrating the macroeconomic factors. This study has employed the exponential generalised autoregressive conditional heteroscedasticity (EGARCH) technique to develop the volatility spillover effect among pan-Asian countries. The results reveal high volatility of listed property companies recorded in Hong Kong and China, while Singapore, The Philippines and Japan have shown low volatility spillovers. In terms of macroeconomic factors, gross domestic product (GDP) and money supply (MS) are the most significant factors in influencing the volatility spillover effect among pan-Asian countries. From the standpoint of regional investors, the volatility spillover characteristics of pan-Asian countries will aid property stakeholders in the region in developing their own methods for making investment decisions in the property security market. Furthermore, in uncertain conditions of the financial market, this study will elevate the transparency of the pan-Asian property portfolio market by providing information on the property market volatility spillovers.info:eu-repo/semantics/publishedVersio

Estimação dos volumes das seções do bulbo úmido na irrigação por ponto.

bitstream/CPATC-2009-09/20596/1/cot-51.pd

A PP2A-B55-Mediated Crosstalk between TORC1 and TORC2 Regulates the Differentiation Response in Fission Yeast

Extracellular cues regulate cell fate, and this is mainly achieved through the engagement of specific transcriptional programs. The TORC1 and TORC2 complexes mediate the integration of nutritional cues to cellular behavior, but their interplay is poorly understood. Here, we use fission yeast to investigate how phosphatase activity participates in this interplay during the switch from proliferation to sexual differentiation. We find that loss of PP2A-B55$^{Pab1}$ enhances the expression of differentiation-specific genes and leads to premature conjugation. $\textit{pab1}$ deletion brings about a transcriptional profile similar to TORC1 inactivation, and deletion of $\textit{pab1}$ overcomes the repression of differentiation genes in cells overexpressing TORC1. Importantly, we show that this effect is mediated by an increased TORC2-AKT (Gad8) signaling. Under nutrient-rich conditions, PP2A-B55$^{Pab1}$ dephosphorylates Gad8 Ser546, repressing its activity. Conversely, TORC1 inactivation upon starvation leads to the inactivation of PP2A-B55$^{Pab1}$ through the Greatwall-Endosulfin pathway. This results in the activation of Gad8 and the commitment to differentiation. Thus, PP2A-B55$^{Pab1}$ enables a crosstalk between the two TOR complexes that controls cell-fate decisions in response to nutrient availability.We thank Dominique Helmlinger and Sergio Moreno for sharing unpublished results and strains, and for stimulating discussion. We thank Janni Petersen, Ronit Weisman, Kazuhiro Shiozaki, Mitsuhiro Yanagida, and Hisao Masukata for strains, constructs, and antibodies. We thank Toni Hurtado and Beata Grallert for critical reading of the manuscript. This work was supported by NFR FRIMEDBIO grant 214049. M.P. is the recipient of a Kreftforeningen postdoctoral fellowship (grant 5843744). N.C. has received funding from the European Union Seventh Framework Programme (FP7-PEOPLE-2013-COFUND) under grant agreement 609020 - Scientia Fellows. J.M. was supported by BBSRC research grants BB/N007697/1 and BB/M021483/1

Optimization and validation of a new microbial inhibition test for the detection of antimicrobial residues in living animals intended for human consumption

Even though antibiotics are necessary in livestock production, they can be harmful not only due to their toxicity, but also in view of their contribution to the emergence of antimicrobial resistance. Screening tests based on microbial growth inhibition appeared to be useful tools to prevent its entry into the food chain. They have nevertheless been traditionally carried out post mortem, leading to great economical loss and harm to the environment in case a positive sample is found. Hence, the objective was to evaluate the use of a screening test as an ante mortem alternative for the detection of antibiotic residues in meat: thus, Explorer®-Blood test was optimized and validated. After adapting the procedure for matrix preparation, the assay parameters were assessed from 344 antibiotic-free blood serum samples. Limits of Detection (LoDs) were defined by spiking blood serum with several of the most common antimicrobials used in veterinary practice. LoDs were similar to those obtained for meat and were at or below the maximum residue limits set by EU legislation for muscle. Analyses of in vivo injected samples, previously characterized by LC-MS/MS, demonstrated the method’s accuracy and proved that Explorer®-Blood can be considered a suitable alternative to conventional post mortem screening methods

A declining major merger fraction with redshift in the local Universe from the largest-yet catalog of major and minor mergers in SDSS

It is difficult to accurately identify galaxy mergers and it is an even larger challenge to classify them by their mass ratio or merger stage. In previous work we used a suite of simulated mergers to create a classification technique that uses linear discriminant analysis (LDA) to identify major and minor mergers. Here, we apply this technique to 1.3 million galaxies from the SDSS DR16 photometric catalog and present the probability that each galaxy is a major or minor merger, splitting the classifications by merger stages (early, late, post-coalescence). We present publicly-available imaging predictor values and all of the above classifications for one of the largest-yet samples of galaxies. We measure the major and minor merger fraction ($f_{\mathrm{merg}}$) and build a mass-complete sample of galaxies, which we bin as a function of stellar mass and redshift. For the major mergers, we find a positive slope of $f_{\mathrm{merg}}$ with stellar mass and negative slope of $f_{\mathrm{merg}}$ with redshift between stellar masses of $10.5 < M_* (log\ M_{\odot}) < 11.6$ and redshifts of $0.03 < z < 0.19$. We are able to reproduce an artificial positive slope of the major merger fraction with redshift when we do not bin for mass or craft a complete sample, demonstrating the importance of mass completeness and mass binning. We determine that the positive trend of the major merger fraction with stellar mass is consistent with a hierarchical assembly scenario. The negative trend with redshift requires that an additional assembly mechanism, such as baryonic feedback, dominates in the local Universe.Comment: 29 pages, 22 figures, see figures 16 and 17 for a summary of the findings, accepted to MNRA