On the Performance of a Two-Stage Vibration Isolation System Which has Geometrically Nonlinear Stiffness

Linear single-stage vibration isolation systems have a limitation on their performance, which can be overcome passively by using linear two-stage isolations systems. It has been demonstrated by several researchers that linear single-stage isolation systems can be improved upon by using nonlinear stiffness elements, especially for low-frequency vibrations. In this paper, an investigation is conducted into whether the same improvements can be made to a linear two-stage isolation system using the same methodology for both force and base excitation. The benefits of incorporating geometric stiffness nonlinearity in both upper and lower stages are studied. It is found that there are beneficial effects of using nonlinearity in the stiffness in both stages for both types of excitation. Further, it is found that this nonlinearity causes the transmissibility at the lower resonance frequency to bend to the right, but the transmissibility at the higher resonance frequency is not affected in the same way. Generally, it is found that a nonlinear two-stage system has superior isolation performance compared to that of a linear two-stage isolator.

Avaliação do uso de fantomas antropomórficos na análise experimental dos fatores que afetam o contraste de imagens radiográficas

This experimental study aimed the evaluation of the use of anthropomorphic phantoms in the analysis of the influence of the acquisition parameters in the contrast of radiographic images. The analyzed factors were the variation of the peak kilovoltage (kVp) and the product of the filament circuit by the time of exposition (mAs). The influence of these factors was verified for different anthropomorphic phantoms: foot, knee and chest. The image contrast behavior with the simulators was compared to values obtained with the use of an aluminum ladder being the behavior of this reference for analysis and discussion. To assure the reproducibility of images, quality control tests were made and evaluation of procedure conditions before the experiments. The results obtained are shown in a scale of images where it was possible to evaluate the impact in the darkness of images. Regions with different compositions were analyzed which were different in image, this way the values of optical density and contrast are represented as charts and graphics. We conclude that the use of anthropomorphic phantoms in the evaluation of the influence of tension of the tube and time of exposition in the contrast of the radiographic images is not indicated for a quantitative analysis through optical density, once they present incompatible results with the data as reference as the aluminum ladder even so these simulators present a great property in qualitative analysis regarding the differentiation of structures and subjective evaluations

Classificação de impressões digitais

The biometric characteristics have been used increasingly as a way to identify an individual, mainly for security reasons. Among them, the fingerprint is the most used biometric characteristic around the world, because it is relatively simple and very efficient. In this scene, there was a significant increase in the size of databases containing information on fingerprints, necessary to perform the recognition of a person. The task of classifying them beforehand has become extremely important as it reduces dramatically the size of the problem during a search, because it is not necessary to go through the whole database. Considering its importance, in the last thirty years, many techniques have been developed to try to increase the efficiency of the classification process. This project followed the rules-based approach and the Software Development Kit (SDK) VeriFinger 6.1 was used to assist in the detection of cores and deltas. Additionally, the classification was also implemented by means of directional map and the Poincar´e index. To make the experiments, the number four database from the National Institute of Standards and Technology (NIST) was used, which is a standard in this area

A decoding procedure which improves code rate and error corrections

Corresponding to $C_{0}[n,n-r]$, a binary cyclic code generated by a primitive irreducible polynomial $p(X)\in \mathbb{F}_{2}[X]$ of degree $r=2b$, where $b\in \mathbb{Z}^{+}$, we can constitute a binary cyclic code $C[(n+1)^{3^{k}}-1,(n+1)^{3^{k}}-1-3^{k}r]$, which is generated by primitive irreducible generalized polynomial $p(X^{\frac{1}{3^{k}}})\in \mathbb{F}_{2}[X;\frac{1}{3^{k}}\mathbb{Z}_{0}]$ with degree $3^{k}r$, where $k\in \mathbb{Z}^{+}$. This new code $C$ improves the code rate and has error corrections capability higher than $C_{0}$. The purpose of this study is to establish a decoding procedure for $C_{0}$ by using $C$ in such a way that one can obtain an improved code rate and error-correcting capabilities for $C_{0}$.

Proposição de uma prática experimental significativa em aulas de física

A remarkable characteristic of the physics subject is the abstraction ability needed during the learning process, which means a non-trivial comprehension and understanding. If the students could not link the themes learned in this subject with observable effects, physics would tend to be a group of mathematical formulas to be memorized. In general, it creates a distance between the student and the subject, and also a prejudice vision of the physics, sometimes for the whole life. Beyond this particular characteristics of physics, the education deals with a source of distraction reinforced by the popularization of mobile access such as cellphones and tablets. The traditional role played by the teacher becomes weak to attract student’s attention. It is necessary that the classes could be planned in such way to achieve three goals: attract student attention, link analytical concepts with real effects and, the most important, gives to the student the ability to use the learned concepts as the key to develop new knowledge. In this work, we present a research based in some experiments used in a CBEF (Brazilian magazine about physical education) and develop an activity consistent with the aims to be reached. To prepare of the experimental activity, we based on Piaget and Vygotsky theories. This work aimed to developed a theoretical research to obtain a didactical activity that deals with the current challenges of the society

An Informatics Technical Note on Interaction of DNA - Graphene Chemical Sensor System as Reaction-Diffusion Wave-Based Computing System in Ionised Gaseous environments and their Applications Using Theoretical Studies and Scientific Computation Overview

The physics of plasmas encompasses basic problems from the universe and has assured us of promises in diverse applications to be implemented in a wider range of scientific and engineering domains, linked to most of the evolved and evolving fundamental problems. Substantial part of this domain could be described by R–D mechanisms involving two or more species (reaction–diffusion mechanisms). These could further account for the simultaneous non-linear effects of heating, diffusion and other related losses. We mention here that in laboratory scale experiments, a suitable combination of these processes is of vital importance and very much decisive to investigate and compute the net behaviour of plasmas under consideration. Plasmas are being used in the revolution of information processing, so we considered in this technical note a simple framework to discuss and pave the way for better formalisms and Informatics, dealing with diverse domains of science and technologies. The challenging and fascinating aspects of plasma physics is that it requires a great deal of insight in formulating the relevant design problems, which in turn require ingenuity and flexibility in choosing a particular set of mathematical (and/or experimental) tools to implement them.

"Will It Rain?" Activities Investigating Aerosol Hygroscopicity and Deliquescence

Climate change and its consequences seem to be increasingly evident in our daily lives. However, is it possible for students to identify a relationship between these large-scale events and the chemistry taught in the classroom? The aim of the present work is to demonstrate that chemistry can assist in elucidating important environmental issues. Simple experiments are used to demonstrate the mechanism of cloud formation, as well as the influence of anthropogenic and natural emissions on the precipitation process. The experiments presented show the way in which particles of soluble salts commonly found in the environment can absorb water in the atmosphere and influence cloud formation.

O jogo como mediador na entrevista: um novo lugar no processo psicoterápico com adolescentes

It is a fact that between the child and the adult there is an adolescent being that experiments his experiences in a different way than those others. Therefore, in clinical care, the use of toys and play do not have the same value as for the children, and, on the other hand, the majority of adolescents are not ready, as the adult is, for the exclusive use of speech in the psychotherapy context. There is the need to introduce some specific strategy in order to give the adolescent conditions to express himself openly in the psychotherapy process. The mediator's resource introduces this variable to enable the expression of emotions for those who cannot find the available channels for that. This paper seeks to answer this question by presenting the Time Tunnel Game in the psychotherapy with young people, based, during several years, on its clinical use with patients during this period of their lives. Explaining, when it is a question of a demand for a game, that the youngster tries to respect the rules, therefore, expressing his experiences more at ease. By using the mentioned game, it is not the psychotherapist that questions or addresses the youngster, but it is through this playing that the questions arise, providing the youngster a facilitating context for his experiences, even for the more difficult ones. At the direct request of the psychotherapist, it is possible that the adolescent may have the imposing idea that he is being evaluated, which is inadequate when attending any youngster. It is understood that this facilitation also occurs because in a game the atmosphere of lucidity is less threatening to the patient to reveal himself as playing. It is the game that "interviews" and, therefore, the youngster has less to be afraid of when expressing his experiences.

Visão estéreo para auxílio à navegação autônoma em ambientes agrícolas

Pós-graduação em Ciência da Computação - IBILCE

Constraining the absolute neutrino mass scale and Majorana CP violating phases by future 0νββ decay experiments

Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating Majorana phases, and how they can be accessed by future neutrinoless double beta (0vυββ) decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on m 0, the lightest neutrino mass, that can be inferred if the next generation 0υββ decay experiments can probe the effective Majorana mass (m ee) down to ∼1 meV. In this context we conclude that in the case that neutrinos are Majorana particles, (a) if m 0≳300 meV, i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then m ee≳30 meV must be observed, (b) if m 0 ≤ 300 meV, results from future 0υββ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of m 0 than these direct experiments. For instance, if a positive signal is observed around m ee = 10 meV, we estimate 3≲m 0/meV≲65 at 95% C.L.; on the other hand, if no signal is observed down to m ee = 10 meV, then m 0≲55 meV at 95% C.L.

O ensino de física e a curiosidade epistemológica: o uso de experimentos de eletricidade em atividades educacionais

We analyzed with this work the importance of using experiments in the classroom, especially the low-cost experiments for better learning of Physics, discussing the context where this discipline is inserted, which in general, has been presented to students in a traditional, mechanistic way. We worked with the electrostatic theme and low cost didactic experiments, focusing on the pizza electrophorus. About the handling of this experiment, we can see the surprise and curiosity in students, depending on how it is used in didactic activities in order to make it meaningful to the student. We discussed how the curiosity can be harnessed in the classroom, the types of curiosity according to Freire, how to overcome the curiosity to become epistemological, the physics involved in the experiment and the teacher's role in this context

O CAD 3D aplicado na validação de protótipos na indústria do vestuário

Pós-graduação em Design - FAAC

Elaboração de um material didático aplicado ao ensino de física para utilização do experimento virtual da dupla fenda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fenomenologia e neurociência: uma relação possível

Pós-graduação em Filosofia - FFC

Seleção de genótipos de soja portadores ou não do gene RR por meio de análise multivariada e desempenho agronômico

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)