Search

It was shown recently that the Force Feedback Microscope (FFM) can avoid the jump-to-contact in Atomic force Microscopy even when the cantilevers used are very soft, thus increasing force resolution. In this letter, we explore theoretical aspects of the associated real time control of the tip position. We take into account lever parameters such as the lever characteristics in its environment, spring constant, mass, dissipation coefficient, and the operating conditions such as controller gains and interaction force. We show how the controller parameters are determined so that the FFM functions at its best and estimate the bandwidth of the system under these conditions. [ABSTRACT FROM AUTHOR]

Objective: report and describe the satisfactory evolution of Ludwig’s Angina due to a tonsillary infection, which evolved to mediastinitis and sept shock. The work aims to detail the clinical and diagnostic aspects of this serious illness, in addition to the therapy used in this case. Method: the information was obtained from the patient’s medical record, as well as from the reports of the imaging tests performed. The literature review was carried out in the PUBMED database. Final considerations: the case studied has great importance for the medical community, since it reports a rare favorable outcome for a case of Ludwig’s Angina complicated with an mediastinitis, whose mortality is described up to 50% of the cases. The surgical approach combined with early antibiotic therapy is shown to be the best approach for these cases.

The IIW White Paper is a booklet produced by a panel of 80 experts of the IIW, aimed at providing reader with a picture on welding and allied technologies dated 2012, but mainly focused on the challenges and direction of these technologies for the next 20 years. Statistical data on value added by welding and welding related occupation are included in the first part, while the main content is devoted to evaluating technologies, processes, materials, inspection and testing techniques, standard and codes which can potentially become state of the art in the next years. A section is also devoted to identify those changes in the industrial world that can impress a driving force to welding and allied technologies. The article is a non-exhaustive resume of the IIW White Paper, while the full document is available for free on the IIW website (www.iiwelding.org). [ABSTRACT FROM AUTHOR]

Performing an heat treatment may he necessary in order to satisfy the requirements that the final quality and the service conditions may impose to a welded component. The relevant technical and operational complexity often requires the application of codes and standards (European and International). In this respect, this paper is focused on AWS standard D10.10: "Recommended Practices for Local Heating of Welds in Piping and Tubing". This reference not only provides essential information related to the realization of localized heat treatment on pipes but is integrated with requirements included in other standards both European (e.g. the BS 2633) and International (e.g. ASME B31.1, B31.3). [ABSTRACT FROM AUTHOR]

The force between two particles as a function of distance is one of the most fundamental curves in physics. Here, we describe how the force feedback microscope can routinely measure the tip-surface interaction in the entire range of distances with a sensitivity of 1 pN and in different media. The method allows to measure simultaneously the force, force gradient, and damping from solely the knowledge of the lever spring constant. The jump to contact is avoided and thus it is possible to follow the brutal nucleation of a water bridge between the tip and the surface. [ABSTRACT FROM AUTHOR]

Objeto de aprendizagem (OA) é um conjunto de conteúdos educacionais com um arquivo de metadados responsável pela descrijao técnica e educacional destes conteúdos, a partir da qual é possível compartilhar OAs em repositorios educacionais, desde que ambos metadados e repositorio fajam uso do mesmo padrao, como o IEEE LOM, o CanCore ou o OBAA - sendo este último o padrao de referencia brasileiro. Assim, propoe-se o desenvolvimento de uma ferramenta cuja origem dá-se na deficiencia de ferramentas de criajao de OA em apresentar as características nesta empregadas, tais como ser grátis, fácil de usar e nao requerer instalajao, bem como utilizar a especificajao OBAA e o modelo SCORM. Objetiva-se com seu uso facilitar, para o professor, a criajao de conteúdos didáticos e incentivar os alunos a inventarem seus próprios materiais, bem como disseminar a utilizajao do modelo OBAA. Para tanto, realizou-se, através de websites, artigos académicos e da leitura dos trabalhos de Wiley e Silva, estudo dos objetos de aprendizagem, seus metadados, especificajoes e ferramentas relacionadas, bem como das tecnologias necessárias para a criajao do sistema proposto. Com as funcionalidades principais já operantes, é tangível que a aplicajao aqui apresentada, mesmo em estágio inicial de desenvolvimento, atende ao perfil destacado.

We present a method to tune the resonance frequency and the Q-factor of micro and nano-metric mechanical oscillators. A counteracting loop drives a capacitive force applied to the oscillator. The proportional and differential gains are used to shift the resonance frequency up to 75% and to tune the Q-factor of the oscillator, by changing its effective stiffness and damping ratio. The oscillator position is monitored in a large bandwidth with a fiber-optic based interferometer. We applied this simple operational scheme with different oscillators for modifying easily their dynamical properties. Compared to alternative methods requiring external fields, our method can either increase or decrease the resonance frequency in a frequency range much more extended. This opens up a wide range of applications, from force sensors with extremely low elastic constants but high quality factor to tunable energy harvesters or to high-frequency tuning of radio frequency filters. The control scheme can work in different media, and is then suitable to be applied to biological sensors and actuators. [ABSTRACT FROM AUTHOR]

The sixty-seventh Annual Assembly of the International Institute of Welding, "a world of joining experience", was held in Seoul, capital of South Korea, from 13 to 18 July 2014. Participants were 755, among experts, researchers, technicians and attendants, of 46 countries from four continents. In the over one hundred sessions of the numerous IIW Working Units were presented, discussed and studied more than five hundred documents, recommendations, guidelines and draft standards: about 150 of them have been recommended for publication while some additional documents were sent to ISO and CEN for publication as standards or other regulatory actions. The article presents the most significant documents analized and discussed during the technical sessions, summarized by the members of the italian delegation. During the Assembly the meetings of the IAB (International Authorization Board) were held; the body has been created to manage within the IIW's the "International IIW Qualification, Certification and Authorization System". [ABSTRACT FROM AUTHOR]