Filters








1,191 Hits in 2.0 sec

Piezoelectric Plates Distribution for Active Control of Torsional Vibrations

Fabio Botta, Federico Toccaceli
2018 Actuators  
The active vibration control systems have received considerable attention in various areas of mechanical engineering. The advent of smart materials has significantly increased the available solutions for engineers in this field. Among these, piezoelectric materials are among the most promising ones but their placement is an important parameter for their efficiency. The optimal placement to damp the flexural modes is a topic widely studied in the literature but this is not for the torsional
more » ... . In this paper a new analytical method to find the optimal placement of piezoelectric plates to control the multimode torsional vibrations of a cantilever beam is proposed. The results are compared with those obtained by a finite element code with a very good agreement.
doi:10.3390/act7020023 fatcat:u2unrdgupbd2tdz7vur2iexubu

Relaxivity modulation in Gd-functionalised mesoporous silicas

Fabio Carniato, Lorenzo Tei, Walter Dastrù, Leonardo Marchese, Mauro Botta
2009 Chemical Communications  
doi:10.1039/b820591d pmid:19240888 fatcat:tvhswechgzdr3pu4zpqoswmyli

Analytical Modeling of a New Compliant Microsystem for Atherectomy Operations

Pietro Ursi, Andrea Rossi, Fabio Botta, Nicola Pio Belfiore
2022 Micromachines  
This work offers a new alternative tool for atherectomy operations, with the purpose of minimizing the risks for the patients and maximizing the number of clinical cases for which the system can be used, thanks to the possibility of scaling its size down to lumen reduced to a few tenths of mm. The development of this microsystem has presented a certain theoretical work during the kinematic synthesis and the design stages. In the first stage a new multi-loop mechanism with a Stephenson's
more » ... c chain (KC) was found and then adopted as the so-called pseudo-rigid body mechanism (PRBM). Analytical modeling was necessary to verify the synthesis requirements. In the second stage, the joint replacement method was applied to the PRBM to obtain a corresponding and equivalent compliant mechanism with lumped compliance. The latter presents two loops and six elastic joints and so the evaluation of the microsystem mechanical advantage (MA) had to be calculated by taking into account the accumulation of elastic energy in the elastic joints. Hence, a new closed form expression of the microsystem MA was found with a method that presents some new aspects in the approach. The results obtained with Finite Element Analysis (FEA) were compared to those obtained with the analytical model. Finally, it is worth noting that a microsystem prototype can be fabricated by using MEMS Technology classical methods, while the microsystem packaging could be a further development for the present investigation.
doi:10.3390/mi13071094 pmid:35888911 pmcid:PMC9323221 fatcat:2cbiw3vlzfbpjb4bf54j4s6i4e

Mechanical Response of Four-Bar Linkage Microgrippers with Bidirectional Electrostatic Actuation

Fabio Botta, Matteo Verotti, Alvise Bagolini, Pierluigi Bellutti, Nicola Belfiore
2018 Actuators  
This paper presents both an experimental and a numerical study concerning the mechanical response of a silicon microgripper with bidirectional electrostatic actuation to externally applied excitations. The experimental set-up is composed of a probe station equipped with mobile probes that apply contact forces. This part of the investigation aims to test the device's mechanical resistance, its mobility capability and possible internal contacts during the system deformation. The second part of
more » ... paper is dedicated to the study of the free undamped vibrations of the microsystem. Finite Element Analysis (FEA) is carried out to evaluate the system vibration modes. The analysis of the modes are useful to predict possible mechanical interference among floating and anchored fingers of the actuating comb drives.
doi:10.3390/act7040078 fatcat:qxqhwbj3vbc6xaj2mjkggqs62e

Novel paramagnetic clays obtained through intercalation of Gd3+-complexes

Stefano Marchesi, Fabio Carniato, Chiara Bisio, Lorenzo Tei, Leonardo Marchese, Mauro Botta
2018 Dalton Transactions  
The intercalation of two positively charged Gd3+-complexes into the interlamellar layer of synthetic saponite leads to a novel class of paramagnetic clays with good thermal stability and enhanced relaxometric properties.
doi:10.1039/c8dt00875b pmid:29761810 fatcat:zxlehxzlgbbjlhwd4zdplkxxwm

Real-Time Detection System of Driver Distraction Using Machine Learning

Fabio Tango, Marco Botta
2013 IEEE transactions on intelligent transportation systems (Print)  
Fabio Tango crashes involved driver distraction [4] .  ...  Marco Botta is with Dipartimento di Informatica, Università di Torino, corso Svizzera 185, 10149 Torino, Italy; e-mail: marco.botta@unito.it.  ...  Marco Botta graduated, with laude, in Computer Science at Universita` di Torino in 1987. He received the Ph. D. in Computer Science from Universita` di Torino in 1993.  ... 
doi:10.1109/tits.2013.2247760 fatcat:4ulw4imqybd5pkt6jdu6ug4tpm

Estruturação de um Banco de Dentes Humanos

Alessandra Cristina da Silva Nassif, Fabio Tieri, Patricia Aparecida da Ana, Sérgio Brossi Botta, José Carlos Pettorossi Imparato
2003 Pesquisa Odontológica Brasileira  
Um Banco de Dentes Humanos (BDH) é uma instituição sem fins lucrativos, vinculada a uma faculdade, universidade ou outra instituição. Seu propósito é suprir as necessidades acadêmicas, fornecendo dentes humanos para pesquisa ou para treinamento laboratorial pré-clínico dos alunos, dessa forma eliminando o comércio ilegal de dentes que ainda existe nas faculdades de Odontologia. Cabe também ao BDH zelar pela eliminação da infecção cruzada que existe no manuseio indiscriminado de dentes
more » ... Para o bom funcionamento de um BDH, é fundamental um controle severo de seus procedimentos internos, que incluem a separação e o estoque de dentes, assim como o cadastro e o arquivamento das fichas dos doadores ou beneficiários. Aqui, abordaremos as funções que um BDH pode desempenhar e a forma pela qual hoje o Banco de Dentes Humanos da Faculdade de Odontologia da Universidade de São Paulo (FOUSP) funciona e organiza-se.
doi:10.1590/s1517-74912003000500012 pmid:12937749 fatcat:ue6met5owfhezp3nf5r47kl3ta

Alcohol Excites Cerebellar Golgi Cells by Inhibiting the Na+/K+ ATPase

Paolo Botta, Fabio M Simões de Souza, Thomas Sangrey, Erik De Schutter, C Fernando Valenzuela
2010 Neuropsychopharmacology  
Alcohol increases Golgi cell firing P Botta et al neither action potentials nor any subthreshold membrane potential oscillations were observed (Figure 4a).  ...  Alcohol increases Golgi cell firing P Botta et al DISCUSSION The purpose of this study was to characterize the mechanism by which ethanol excites cerebellar GoCs.  ... 
doi:10.1038/npp.2010.76 pmid:20520600 pmcid:PMC2904864 fatcat:qw3vhjzrdzch3ljn6lw4rkyogm

Calculation Model for Optimization Design of Low Impact Energy Systems for Buildings

Roberto De Lieto Vollaro, Matteo Calvesi, Gabriele Battista, Luca Evangelisti, Fabio Botta
2014 Energy Procedia  
This study represents a new way for an innovative method of thermo-mechanical design for all buildings (new and historical), with the purpose to assess the feasibility of innovative plants from a technical, economic and environmentally point of view. The thermal loads, starting from the analysis of consumers' parameters, were calculated via TRNSYS and the results were processed using RETScreen. With the latter a comparison between a conventional plant and one based on innovative technologies was carried out.
doi:10.1016/j.egypro.2014.02.165 fatcat:tdzxm73z6fctzb7fgdfpggqzfa

A Review on Parametric Dynamic Models of Magnetorheological Dampers and Their Characterization Methods

Andrea Rossi, Francesco Orsini, Andrea Scorza, Fabio Botta, Nicola Belfiore, Salvatore Sciuto
2018 Actuators  
Magnetorheological (MR) fluids are capable of manifesting a rheological behaviour change by means of a magnetic field application and can be employed in many complex systems in many technical fields. One successful example is their use in the development of dampers: magnetorheological dampers (MRDs) are widespread in vibration control systems, as well as civil engineering applications (i.e., earthquake or seismic protection), impact absorption and vibration isolation technology in industrial
more » ... ineering, and advanced prosthetics in biomedical fields. In the past, many studies have been conducted on MRDs modeling and characterization, but they have usually been focused more on the theoretical models than on the experimental issues. In this work, an overview of both of them is proposed. In particular, after an introduction to the physics of the magnetorheological effect, a short review of the main mathematical models of MRDs is proposed. Finally, in the second part of this study an overview of the main issues that occur in MRDs experimental characterization is reported and discussed.
doi:10.3390/act7020016 fatcat:yw5wnggicfc7fdmz7qsslng6ui

Structural Basis of Enzymatic (S)-Norcoclaurine Biosynthesis

Andrea Ilari, Stefano Franceschini, Alessandra Bonamore, Fabio Arenghi, Bruno Botta, Alberto Macone, Alessandra Pasquo, Luca Bellucci, Alberto Boffi
2008 Journal of Biological Chemistry  
The enzyme norcoclaurine synthase (NCS) catalyzes the stereospecific Pictet-Spengler cyclization between dopamine and 4-hydroxyphenylacetaldehyde, the key step in the benzylisoquinoline alkaloid biosynthetic pathway. The crystallographic structure of norcoclaurine synthase from Thalictrum flavum in its complex with dopamine substrate and the nonreactive substrate analogue 4-hydroxybenzaldehyde has been solved at 2.1 Å resolution. NCS shares no common features with the functionally correlated
more » ... ctet-Spenglerases" that catalyze the first step of the indole alkaloids pathways and conforms to the overall fold of the Bet v1-like protein. The active site of NCS is located within a 20-Å -long catalytic tunnel and is shaped by the side chains of a tyrosine, a lysine, an aspartic, and a glutamic acid. The geometry of the amino acid side chains with respect to the substrates reveals the structural determinants that govern the mechanism of the stereoselective Pictet-Spengler cyclization, thus establishing an excellent foundation for the understanding of the finer details of the catalytic process. Site-directed mutations of the relevant residues confirm the assignment based on crystallographic findings. 2 The abbreviations used are: 4-HPAA, 4-hydroxyphenylacetaldehyde; NCS, norcoclaurine synthase; SeMet, selenomethionine; PHB, 4-hydroxybenzaldehyde.
doi:10.1074/jbc.m803738200 pmid:19004827 fatcat:of6lic4xxjgp5ddrfq2ovlfxue

Electronic Effects of the Substituents on Relaxometric and CEST Behaviour of Ln(III)-DOTA-Tetraanilides

Valeria Lagostina, Loredana Leone, Fabio Carniato, Giuseppe Digilio, Lorenzo Tei, Mauro Botta
2019 Inorganics  
Three different 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetamide (DOTAM) derivatives bearing as amide N-substituents phenyl, p-methoxyphenyl and p-ethylbenzoate groups were synthesized and the 1H and 17O NMR relaxometric behaviour of the Gd(III)-chelates and chemical exchange saturation transfer (CEST) effect of the Eu(III) complexes were evaluated. The electronic properties of the substituents were shown to strongly influence the coordinated water exchange rate (kex), resulting in five
more » ... mes faster kex for the electron donating phenylmethoxy group compared to the electron withdrawing ethylbenzoate group.
doi:10.3390/inorganics7040043 fatcat:g5cnfqrjxzekzdh4pfeqyrho3i

Response of Composite Beam Structure under Unbalanced Excitation of Rice Threshing System

Xujun Zhai, Xingqin You, Hao Zhang, Zhong Tang, Xinzhong Wang, Guoqiang Wang, Fabio Botta
2022 Shock and Vibration  
This paper studies the dynamic response of the support beam under the unbalanced excitation of the rice threshing system. The differential equation of motion of the supporting beam under the action of harmonic force is established by the modal superposition method, and its dynamic response is analyzed. It is found that the initial vibration of the supporting beam will fluctuate greatly when it is excited by the unbalanced force. In response to this problem, the application of composite beams as
more » ... the support structure of the threshing system is proposed. The composite beam is mainly composed of uniform and isotropic Euler–Bernoulli beams that are parallel to each other, and the two beams are connected by elastic spring elements. Then, the vibration response of the composite beam structure under unbalanced forces is studied. The results show that the vibration of the composite beam is more stable when it is excited by the unbalanced drum. The overall vibration response amplitude is smaller than that with single support, and the vibration reduction effect is obvious. When the stiffness changes, the change trend of the response amplitude of beam 1 and beam 2 is opposite, that is, the stiffness increases, the vibration amplitude of beam 1 decreases, and the amplitude of beam 2 increases. This shows that the composite beam is suitable for the support structure of the harvester.
doi:10.1155/2022/5792102 fatcat:fftwu2cjbfgyngd6ilq5siiasi

Isogeometric Analysis for Active Control of Piezoelectric Functionally Graded Plates in Thermal Environment

Tao Liu, Yafen Jiang, Shujun Li, Qingyun Liu, Chao Wang, Fabio Botta
2021 Shock and Vibration  
An isogeometric analysis (IGA) method is proposed for investigating the active shape and vibration control of functionally graded plates (FGPs) with surface-bonded piezoelectric materials in a thermal environment. A simple first-order shear deformation theory (S-FSDT) with four variables is used to describe the displacement field of the plates. To ensure the investigation of smart piezoelectric structure in the thermal environment closer to the actual situation, a modified piezoelectric
more » ... tive equation with consideration of the temperature effect of dielectric and piezoelectric strain coefficients is implemented to replace the traditional linear piezoelectric constitutive equation. Meanwhile, the neutral surface is adopted to avoid the stretching-bending coupling. The accuracy and effectiveness of the proposed S-FSDT-based IGA method are verified by comparing with several existing numerical examples. Then, the static bending and open-loop control of the plates under mechanical and thermal loads are further studied. Finally, the active control including static bending control and vibration control of piezoelectric functionally graded plates (PFGPs) is also investigated by using a displacement-velocity feedback control law.
doi:10.1155/2021/5514476 fatcat:sdqyyxriq5a4xfb6tcizhesr4i

New MEMS Tweezers for the Viscoelastic Characterization of Soft Materials at the Microscale

Paolo Di Giamberardino, Alvise Bagolini, Pierluigi Bellutti, Imre Rudas, Matteo Verotti, Fabio Botta, Nicola Belfiore
2017 Micromachines  
Matteo Verotti and Fabio Botta developed the equations adopted for the kinematic and dynamic analysis of the system. Matteo Verotti and Nicola P.  ... 
doi:10.3390/mi9010015 pmid:30393290 pmcid:PMC6187331 fatcat:hayu2pdofbf55f7yiz6v5hgf3y
« Previous Showing results 1 — 15 out of 1,191 results