Time-domain deconvolution procedure for elastoplastic materials: Application to the Treasure Island site during the 1989 Loma Prieta earthquake.

When dynamic soil-structure interaction (DSSI) analyses are performed, e.g. using the finite element (FE) method, the input signal is required at the base of the model. Nevertheless, acceleration records are usually available at the surface and, therefore, the desired motion must be deconvolved to the base. The latter is usually performed through the solution of one-dimensional propagation of shear waves in an elastic medium, in the frequency domain. Herein, nonlinear behavior is generally incorporated through the equivalent-linear method, by iteratively reducing the stiffness and increasing the critical damping ratio as a function of the maximum strains attained in each iteration. However, if complex material models are adopted to characterize the soil, the input motion derived with the equivalent linear method will not be compatible due to the simplified approach used to represent the nonlinear behavior. In this article, the use of a procedure to perform a time-domain deconvolution in non-linear elastoplastic materials is demonstrated. The goal is to generate input accelerograms at the base of a FE model to perform DSSI analyses. The procedure is based on the iterative modification of the motion at the base according to the relative differences between the propagated and target surface spectra. To illustrate the use of the methodology, it was applied to a FE model of the Treasure Island site (San Francisco, US), to derive the required motion at the base from a record of the Loma Prieta earthquake.•This article provides a useful guideline to optimize the use of the deconvolution procedure to derive input motions for dynamic FE analyses considering nonlinear elastoplastic materials.

Performance of Medium-Rise Buildings with Reinforced Concrete Shear Walls Designed for High Seismic Hazard.

This work has evaluated the collapse fragility of a typical Chilean building for residential use, structured based on shear-resistant RC walls and inverted beams arranged along its entire perimeter, using the incremental dynamic analysis (IDA) for the evaluation of its structural behavior, using for this the 2018 version of the SeismoStruct software. This method evaluates the global collapse capacity of the building from the graphical representation of its maximum inelastic response, obtained through a non-linear time-history analysis, against the scaled intensity of a set of seismic records obtained in the subduction zone, thus creating the IDA curves of the building. The processing of the seismic records is included within the applied methodology to make them compatible with the elastic spectrum of the Chilean design, achieving an adequate seismic input in the two main structural directions. In addition, an alternative IDA method based on the elongated period is applied to calculate the seismic intensity. The results of the IDA curve obtained with this procedure and the standard IDA analysis are analyzed and compared. The results show that the method relates very well to the structure's demand and capacity and confirms the non-monotonous behavior exposed by other authors. Regarding the alternative IDA procedure, the results indicate that the method is inadequate, failing to improve the results obtained by the standard method.

Rapid Selective Detection and Quantification of ß-Blockers Used in Doping Based on Molecularly Imprinted Nanoparticles (NanoMIPs).

Human performance enhancing drugs (PEDs), frequently used in sport competitions, are strictly prohibited by the World Anti-Doping Agency (WADA). Biological samples collected from athletes and regular patients are continuously tested regarding the identification and/or quantification of the banned substances. Current work is focused on the application of a new analytical method, molecularly imprinted nanoparticles (nanoMIPs), to detect and determine concentrations of certain prohibited drugs, such as ß-blockers, in water and human urine samples. These medications are used in the treatment of cardiovascular conditions, negative effects of adrenaline (helping to relief stress), and hypertension (slowing down the pulse and softening the arteries). They can also significantly increase muscle relaxation and improve heart efficiency. The new method of the detection and quantification of ß-blockers is based on synthesis, characterization, and implementation of nanoMIPs (so-called plastic antibodies). It offers numerous advantages over the traditional methods, including high binding capacity, affinity, and selectivity for target molecules. Additionally, the whole process is less complicated, cheaper, and better controlled. The size and shape of the nanoMIPs is evaluated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The affinity and selectivity of the nanoparticles are investigated by competitive pseudo enzyme-linked immunosorbent assay (pseudo-ELISA) similar to common immunoassays employing natural antibodies. To provide reliable results towards either doping detection or therapeutic monitoring using the minimal invasive method, the qualitative and quantitative analysis of these drugs is performed in water and human urine samples. It is demonstrated that the assay can detect ß-blockers in water within the linear range 1 nmol·L-1-1 mmol·L-1 for atenolol with the detection limit 50.6 ng mL-1, and the linear range 1 mmol·L-1-10 mmol·L-1 for labetalol with the detection limit of 90.5 ng·mL-1. In human urine samples, the linear range is recorded in the concentration range 0.1 mmol·L-1-10 nmol·L-1 for atenolol and 1 mmol·L-1-10 nmol·L-1 for labetalol with a detection limit of 61.0 ng·mL-1 for atenolol and 99.4 ng·mL-1 for labetalol.

Assessment of apical pressures at different automated irrigant flow rates: an ex vivo study based on computational fluid dynamic analysis / Avaliação de pressões apicais em diferentes taxas de fluxo irrigante automatizadas: um estudo ex vivo baseado em análise dinâmica de fluidos computacionais

Objective: The current study aimed at assessing the induced apical pressure at various simulated irrigant flow rates. Materials and Methods: Forty eight freshly extracted single-rooted premolars were decoronated and prepared to size 30 0.04 taper using HY-Flex CM rotary file system and were scanned using cone-beam computed tomography (CBCT). The scanned images were reconstructed to three-dimensional Computer-aided design models (CAD) and the 3D needle was also reconstructed. Finally, simulations were done by placing the 30 gauge open-ended needle 3 mm short of the working length. Results: There was a statistically significant difference (p<0.05) among the different groups compared. 1 ml/min flow rate induced the least apical pressures (p<0.05) as compared to the other types. Conclusion: 1 ml/min flow rates induced the least apical pressures when open-ended needles are used for irrigation.(AU)

Objetivo: O presente estudo teve como objetivo avaliar a indução de pressão apical em várias taxas de fluxo irrigante simuladas. Material e Métodos: Quarenta e oito raízes de pré-molares unirradiculares recém extraídos tiveram suas coroas removidas, foram preparados para uma conicidade de tamanho 30 0.04 através de um sistema rotatório de limas HYFlex CM e foram escaneados via tomografia computadorizada cone-beam (CBCT). As imagens escaneadas e as agulhas para irrigação foram reconstruídas em modelos tridimensionais de design assistido por computador (CAD). Ao final, foram feitas simulações através de agulhas de calibre 30 e 3 mm a menos que o comprimento de trabalho. Resultados: Houve diferença estatisticamente significativa (p<0.05) entre os diferentes grupos. A taxa de fluxo de 1 ml/min induziu as menores pressões apicais (p<0.05) quando comparada às demais taxas. Conclusão: Taxas de fluxo de 1 ml/min induziram as menores pressões apicais quando agulhas de ponta aberta foram utilizadas para irrigação (AU)

Dynamics of the cardiovascular autonomic regulation during orthostatic challenge is more relaxed in women.

Linear dynamic analysis of cardiovascular and respiratory time series was performed in healthy subjects with respect to gender by shifted short-term segments throughout a head-up tilt (HUT) test. Beat-to-beat intervals (BBI), systolic (SYS) and diastolic (DIA) blood pressure and respiratory interval (RESP) time series were acquired in 14 men and 15 women. In time domain (TD), the descending slope of the auto-correlation function (ACF) (BBI_a31cor) was more pronounced in women than in men (p<0.05) during the HUT test and considerably steeper (p<0.01) at the end of orthostatic phase (OP). The index SYS_meanNN was slightly but significantly lower (p<0.05) in women during the complete test, while higher respiratory frequency and variability (RESP_sdNN) were found in women (p<0.05), during 10-20 min after tilt-up. In frequency domain (FD), during baseline (BL), BBI-normalized low frequency (BBI_LFN) and BBI_LF/HF were slightly but significantly lower (p<0.05), while normalized high frequency (BBI_HFN) was significantly higher in women. These differences were highly significant from the first 5 min after tilt-up (p<0.01) and highly significant (p<0.001) during 10-14 min of OP. Findings revealed that men showed instantaneously a pronounced and sustained increase in sympathetic activity to compensate orthostatism. In women, sympathetic activity was just increased slightly with delayed onset without considerably affecting sympatho-vagal balance.

Structural evidence for a fatty acid-independent myotoxic mechanism for a phospholipase A2-like toxin.

The myotoxic mechanism for PLA2-like toxins has been proposed recently to be initiated by an allosteric change induced by a fatty acid binding to the protein, leading to the alignment of the membrane docking site (MDoS) and membrane disrupting site (MDiS). Previous structural studies performed by us demonstrated that MjTX-II, a PLA2-like toxin isolated from Bothrops moojeni, presents a different mode of ligand-interaction caused by natural amino acid substitutions and an insertion. Herein, we present four crystal structures of MjTX-II, in its apo state and complexed with fatty acids of different lengths. Analyses of these structures revealed slightly different oligomeric conformations but with both MDoSs in an arrangement that resembles an active-state PLA2-like structure. To explore the structural transitions between apo protein and fatty-acid complexes, we performed Normal Mode Molecular Dynamics simulations, revealing that oligomeric conformations of MjTX-II/fatty acid complexes may be reached in solution by the apo structure. Similar simulations with typical PLA2-like structures demonstrated that this transition is not possible without the presence of fatty acids. Thus, we hypothesize that MjTX-II does not require fatty acids to be active, although these ligands may eventually help in its stabilization by the formation of hydrogen bonds. Therefore, these results complement previous findings for MjTX-II and help us understand its particular ligand-binding properties and, more importantly, its particular mechanism of action, with a possible impact on the design of structure-based inhibitors for PLA2-like toxins in general.

Dynamic Analysis of the Temperature and the Concentration Profiles of an Industrial Rotary Kiln Used in Clinker Production

ABSTRACT Cement is one of the most used building materials in the world. The process of cement production involves numerous and complex reactions that occur under different temperatures. Thus, there is great interest in the optimization of cement manufacturing. Clinker production is one of the main steps of cement production and it occurs inside the kiln. In this paper, the dry process of clinker production is analysed in a rotary kiln that operates in counter flow. The main phenomena involved in clinker production is as follows: free residual water evaporation of raw material, decomposition of magnesium carbonate, decarbonation, formation of C3A and C4AF, formation of dicalcium silicate, and formation of tricalcium silicate. The main objective of this study was to propose a mathematical model that realistically describes the temperature profile and the concentration of clinker components in a real rotary kiln. In addition, the influence of different speeds of inlet gas and solids in the system was analysed. The mathematical model is composed of partial differential equations. The model was implemented in Mathcad (available at CCA/UFES) and solved using industrial input data. The proposal model is satisfactory to describe the temperature and concentration profiles of a real rotary kiln.

A computational model for dynamic analysis of the human gait.

Biomechanical models are important tools in the study of human motion. This work proposes a computational model to analyse the dynamics of lower limb motion using a kinematic chain to represent the body segments and rotational joints linked by viscoelastic elements. The model uses anthropometric parameters, ground reaction forces and joint Cardan angles from subjects to analyse lower limb motion during the gait. The model allows evaluating these data in each body plane. Six healthy subjects walked on a treadmill to record the kinematic and kinetic data. In addition, anthropometric parameters were recorded to construct the model. The viscoelastic parameter values were fitted for the model joints (hip, knee and ankle). The proposed model demonstrated that manipulating the viscoelastic parameters between the body segments could fit the amplitudes and frequencies of motion. The data collected in this work have viscoelastic parameter values that follow a normal distribution, indicating that these values are directly related to the gait pattern. To validate the model, we used the values of the joint angles to perform a comparison between the model results and previously published data. The model results show a same pattern and range of values found in the literature for the human gait motion.

Classificação de sinais de vozes saudáveis e patológicas por meio da combinação entre medidas da análise dinâmica não linear e codificação preditiva linear / Healthy and pathological voice assessment by means of nonlinear dynamic analysis measures and linear predictive coding

Análise acústica tem sido sugerida como uma ferramenta auxiliar não invasiva e de baixo custo ao diagnóstico de patologias laríngeas. Diversas são as técnicas empregadas, entre as quais técnicas baseadas no modelo linear de produção da fala e na análise dinâmica não linear de sinais de vozes. O primeiro método é baseado na Teoria fonte-filtro, em que a fonte é a laringe e o filtro é o trato vocal. Nesse modelo, os sons surdos são modelados por uma fonte de ruído aleatório e os sons sonoros por um trem de impulsos na frequência fundamental do locutor. Na abordagem não linear são considerados aspectos da voz humana, não explorados no modelo linear, tais como: variação temporal da forma do trato vocal, as ressonâncias associadas à sua fisiologia, as perdas devido ao atrito nas paredes internas do trato vocal, a radiação do som nos lábios, o acoplamento nasal e o comportamento dinâmico associado à vibração das pregas vocais. Neste trabalho são associadas as duas abordagens e avaliado o desempenho na classificação com as características, de forma individual, e a partir da combinação das mesmas. São empregadas oito medidas oriundas da análise dinâmica não linear (dimensão de correlação, quatro medidas de entropia, expoente de Hurst, maior expoente de Lyapunov e o primeiro mínimo da função de informação mútua), além de coeficientes LPC, obtidos a partir da análise preditiva linear. Os resultados sugerem a viabilidade da técnica empregada para a discriminação entre vozes saudáveis e patológicas em geral, como também entre vozes afetadas por patologias laríngeas distintas como edema, nódulos e paralisia nas pregas vocais.

Acoustic analysis has been suggested as a noninvasive aiding and low cost tool for laryngeal disease diagnosis. Several techniques are employed using either the linear model of speech production, or the nonlinear dynamic analysis of voice signals. The first method is based on source-filter theory, in which the source is the larynx and the filter is the vocal tract. In this model, the unvoiced sounds are modeled by a random noise source and the voiced ones by impulse train at the speaker fundamental frequency. In nonlinear approach, aspects of the human voice are considered, not explored in the linear model, such as temporal variation of the vocal tract shape, resonances associated with its physiology, losses due to friction in the vocal tract inner walls, sound radiation in the lips, nose coupling and dynamic behavior associated with vocal fold vibration. This work combines the two approaches and evaluates the performance in classifying the features individually, and from their combination. Eight measures are employed derived from the nonlinear dynamic analysis (correlation dimension, four entropy measures, Hurst exponent, the largest Lyapunov exponent and the first minimum of mutual information function), besides LPC coefficients obtained from linear predictive analysis. The results suggest the feasibility of the employed technique to discriminate between healthy and pathological voices in general, but also among specific laryngeal diseases as vocal fold edema, nodules and paralysis.

Protocolo para el análisis funcional de prótesis para pacientes con amputación parcial de pie / Protocol for the Functional Analysis of Prosthesis in Patients with Partial Foot Amputation

En la actualidad el desarrollo de prótesis presenta problemas que aún no se han solucionado por completo. A pesar de que se han desarrollado varios estudios enfocados a evaluar el funcionamiento de las prótesis, los trabajos que se presentan en la literatura se realizan con suposiciones de carga, de materiales, e incluso se practican bajo condiciones estáticas. La técnica de correlación de imágenes digitales ha sido útil en diversas aplicaciones, pero ha sido poco explorada en el ambiente de las prótesis. En este trabajo se presenta una técnica capaz de medir la deformación real en sistemas protésicos de pacientes amputados, bajo condiciones de carga y postura reales. Empleando el método de correlación de imágenes digitales es posible evaluar la prótesis del paciente sin necesidad de instrumentarla o modificarla. Además es posible conocer los principales puntos de deformación sin tener que fracturar la pieza. Con esta técnica es posible medir las principales zonas de deformación de un sistema protésico, con la ventaja de que la evaluación se pueden llevar a cabo aplicando cargas y posturas reales de un paciente en un análisis dinámico.

At present, the development of prostheses presents problems that have yet to be completely solved. Despite that various studies have been developed to evaluate the functioning of these prostheses, the works presented in the literature are conducted with suppositions of burden, of materials, and are even practiced under static conditions. The technique of Digital image correlation (DIC) has been useful in diverse applications, but has been scarcely explored in the ambience of prostheses. In this work, we present a technique capable of measuring the real deformation of prosthetic systems in patients with amputations, under real conditions of load and posture. Employing the DIC method, it is possible to evaluate a patient?s prosthesis without the need for instrumenting or modifying it. In addition, it is possible to know the main points of deformation without having to ultimate load the piece. With this technique, it is possible to measure the prosthetic system?s main deformation zones, with the advantage that evaluation can be performed applying the real loads and postures of a patient in a dynamic analysis.