Graphene to Graphane: A Theoretical Study

Graphane is a two-dimensional system consisting of a single layer of fully saturated (sp$^3$ hybridization) carbon atoms. In an ideal graphane structure C-H bonds exhibit an alternating pattern (up and down with relation to the plane defined by the carbon atoms). In this work we have investigated using \textit{ab initio} and reactive molecular dynamics simulations the role of H frustration (breaking the H atoms up and down alternating pattern) in graphane-like structures. Our results show that significant percentage of uncorrelated H frustrated domains are formed in the early stages of the hydrogenation process leading to membrane shrinkage and extensive membrane corrugations. These results also suggest that large domains of perfect graphane-like structures are unlikely to be formed, H frustrated domains are always present.Comment: 15 pages, 6 figure

UCEMEPA: Ubiquitous Computing Environment for Monitoring and Evaluating Physical Activity

The physical inactivity has been indicated by the World Health Organization (WHO) as one of the main risk factors for the incidence of Chronic Non-Communicable Diseases (CNCDs). To change this scenario WHO has stimulated regular practice of physical activities because they play an important role in preventing CNCDs. In Brazil, these activities are performed by health units which generate a large amount of data that need treatment. To deal with this problem we developed UCEMEPA, an environment that employs Ubiquitous Computing technologies and wireless communication networks, in order to monitor remotely and evaluate in real-time participants of physical activity groups. This environment automatically collects physiologic data, and provides indicators which will support and direct public policies for promoting physical activity. In this sense the UCEMEPA will contribute for the promotion of health and quality of life, and for the conduction of longitudinal studies aiming to establish correlations between the practice of physical activity and CNCDs prevention

Kirigami Actuators

Thin elastic sheets bend easily and, if they are patterned with cuts, can deform in sophisticated ways. Here we show that carefully tuning the location and arrangement of cuts within thin sheets enables the design of mechanical actuators that scale down to atomically-thin 2D materials. We first show that by understanding the mechanics of a single, non-propagating crack in a sheet we can generate four fundamental forms of linear actuation: roll, pitch, yaw, and lift. Our analytical model shows that these deformations are only weakly dependent on thickness, which we confirm with experiments at centimeter scale objects and molecular dynamics simulations of graphene and MoS$_{2}$ nanoscale sheets. We show how the interactions between non-propagating cracks can enable either lift or rotation, and we use a combination of experiments, theory, continuum computational analysis, and molecular dynamics simulations to provide mechanistic insights into the geometric and topological design of kirigami actuators.Comment: Soft Matter, 201

Dynamics in Times of Ionizing Radiation and Rainfalls in Tropical Region of Brazil

Low energy gamma rays and rainfalls were monitored each minute in the region around São José dos Campos, (230:10`S, 450:53`W) in Brazil, from March 7th to June 28th in 2017. In this period, it was possible to see the dynamic process that occurs between the presence of ionizing radiation (gamma rays) of low energy and the variation of rain intensity in (mm) / min in the same region. During this period, 12 major peaks of radiation intensity corresponding to 12 rains of high and low intensities were observed. This positive rainfall / radiation correlation is very noticeable in the tropical region of Brazil, which is certainly due to the presence of the decay of 238U uranium into radium 226Ra and arriving at the 222Rn radon with α emission particles and low energy gamma radiation. Therefore, the rain interferes in the presence of the local exhalation of the radon gas, causing the washing of this gas in the low atmosphere, increasing the intensity of radiation measured momentarily in that location. This work shows this dynamic measured in this interval in the year 2017, where there was rainy and dry weather in the place

Atributos Físicos E Geoespaciais De Cambissolo E Argissolo De Mata Nativa Em Humaitá, Am

Natural grasslands with savannah-like characteristics associated to forest mosaics are found within Southern and Eastern Amazonas, Western Rondonia and Northern Roraima, being conditioned to local edaphic factors. The aim of this study was to assess both physical and geospatial attributes of an Cambisol under natural grasslands and an Ultisol under a forest fragment in Humaita - AM, Brazil. In each area, we established a sampling grid in the dimensions of 70 x 70 m, with regular sampling spacing of 10 m and three collection depths: 0.0-0.05, 0.05-0.10 and 0.10-0.20 m, totaling 192 sampling points. Macroporosity (MaP), microporosity (MiP), bulk density (Ds) and total porosity (TP) were determined by soil samples with preserved structure, using a volumetric ring. Soil resistance to penetration (SRP) was measured by an automatic penetrometer after being subjected to a 0.006 MPa tension. Data were submitted to descriptive statistics and geostatistics analysis. The soil under natural grasslands showed values considered critical of Ds, SRP, MaP at all evaluated depths, with significant values at 0.10-0.20 m layer of 1.54 kg dm(-3); 2.08 MPa and 0.05 m(3) m(-3), respectively. Ultisol under the forest fragments showed higher range values and consequently greater geospatial continuity due to the assessed physical attributes, since this soil has a greater stability of its physical structure. Based on the physical properties of the soil, structural function ineffectiveness of the Ultisol is a key factor for the occurrence of grassland in this region.322422430FAPEAMSECTI-A

Evaluation of elastic constants of materials using the frequency spectrum

The characterization of materials made with the support of non-destructive techniques has great importance in industrial applications. The ultrasonic techniques are distinguished by good resolution to measure small variations of wave velocities as a result of changes in the character suffered by a particular material. In general these ultrasonic techniques are studied in the time domain, which represents an experimental difficulties when thin materials are analyzed, as well as to attenuate the ultrasonic signal drastically. An ultrasonic technique that uses the frequency domain is used in this study aiming to provide good time measurements to calculate the elastic constants of the first order in an aluminum alloy 6351. With the aid of a statistical approach was possible to have good results of tests performed when compared by a time domain technique already well explored in Ultrasound works produced in the Nuclear Engineering Institute Laboratory (LABUS / IEN) and also presented in most of the package, in good agreement with the theoretical model established in literature and used to validate the experiment, which was found in the results with good approximation. The relevance of this work in the nuclear area is associated with the interest to know the mechanical properties of structural components of the nuclear industry, which is currently studied as a rule, resorting to the computer simulations or previously during the operation of the system

A construção da cidadania a partir da memória e história local: o uso do jornal como fonte do conhecimento histórico

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014O presente trabalho busca expor uma atividade desenvolvida no Colégio Estadual João XXIII - Ensino Fundamental, Médio e Profissional, situado em Irati, Paraná. Com o intuito de intervir com o Programa Institucional de Bolsa de Iniciação à Docência (PIBID) dentro da sala de aula, foi desenvolvida uma atividade nos sextos anos utilizando como recurso metodológico o uso do jornal local, a fim de problematizar a diversidade de fontes do conhecimento histórico, partir do ensino capaz de valorizar a realidade conhecida por eles e, ainda, contribuir no desenvolvimento dos sentidos da cidadania nos alunos, ao passo que após leitura, discussão e problematização do jornal com outras fontes do conhecimento histórico, foi realizado um reflorestamento simbólico da escola, estabelecendo nos alunos o sentido de participação como sujeitos modificadores dos espaços em que vivem, contribuindo na formação cidadã dos estudante