Comparative analysis between a CAD model design and physical models obtained by manufacturing additive technologies using optical scan

This article presents a detailed study of the application of different additive manufacturing technologies (sintering process, three-dimensional printing, extrusion and stereolithographic process), in the design process of a complex geometry model and its moving parts. The fabrication sequence was evaluated in terms of pre-processing conditions (model generation and model STL SLI), generation strategy and physical model post-processing operations. Dimensional verification of the obtained models was undertook by projecting structured light (optical scan), a relatively new technology of main importance for metrology and reverse engineering. Studies were done in certain manufacturing time and production costs, which allowed the definition of an more comprehensive evaluation matrix of additive technologies.

Morphometry and ultra-structure of the intestinal mucosa of broilers fed different additives

This study aimed at evaluating the effect of the use of different growth promoters on the morphometry and ultra-structure of the intestinal mucosa of 42-day-old broilers. A total number of 36 male Cobb broilers was distributed in a randomized experimental design with a 3 x 3 factorial arrangement, with 3 prebiotic and 3 probiotic sources in the feed, summing up 9 treatments, with 4 replicates each. There was a significant interaction (P<0.01) among the studied factor for villi height (VH) in all intestinal segments, and for crypt depth (CD) in the duodenum and the ileum. In the duodenum, higher villi were obtained in the control group, with the combination of B. subtilis and prebiotics, and with the single use of MOS+OA. No VH differences were observed between the control group and those fed prebiotics. In the jejunum, the highest villi were obtained with the use of the bacterial pool, followed by the control group, and by the use of B. subtilis. Higher villi were also obtained in the control group and in the groups fed MOS, when B. subtilis was used in combination with prebiotics, and when the bacterial pool was used individually or in combination with MOS. In the ileum, the highest villi were obtained with the individual use of B. subtilis, and when MOS+OA or MOS were individually used or in combination with the bacterial pool. As to duodenal CID, deeper crypts were observed in the control group and in those fed B. subtilis or MOS+OA. In the ileum, deeper crypts were also found in the control group and those fed B. subtilis. Deeper crypts were also found when the bacterial pool was individually used or in combination with MOS+OA, and with the individual use of MOS. It was concluded that the use of growth promoters was beneficial to Increase intestinal villi height when Bacillus subtilis was used in combination with prebiotics. The other growth promoters (MOS+OA, MOS, and bacterial pool), can be individually used in most situations. The tested growth promoters did not influence intestinal villi density.

A tellurium-based cathepsin B inhibitor: Molecular structure, modelling, molecular docking and biological evaluation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Notes on vibration control of a micro/macromanipulator mounted on a flexible structure

The objective of this study is to describe the design and the implementation of an experimental set-up used to study the dynamics, the experimental identification, and the active vibration control of a flexible structure mounted manipulator system. The system consists of a three-degree-of-freedom cylindrical manipulator system with a flexible link on its tip. A two-degree-of-freedom polar rigid manipulator is mounted on the flexible macromanipulator. The dynamic modelling and experimental modal analysis identification in the frequency domain are being applied to design active digital control strategies for the micro-manipulator system to damp the mechanical vibrations of the flexible structure on the tip of the macro-manipulator system.

On lag controllers: Design and implementation

Sometimes it is inconvenient or expensive to open the loop of a system to insert lag controllers-for instance, when this system is an open-loop system. A new controller structure where the loop is not opened, and that allows the design of lag controllers as in the case where one can open the loop, is presented. This result can be used by educators in undergraduate courses that deal with classic control system theory, because it allows a better comprehension of the concept of lag compensation and provides a new method for its design and implementation. An example illustrates the application of the proposed method.

On relaxed LMI-based design for fuzzy controllers

Relaxed conditions for stability of nonlinear continuous-time systems given by fuzzy models axe presented. A theoretical analysis shows that the proposed method provides better or at least the same results of the methods presented in the literature. Digital simulations exemplify this fact. This result is also used for fuzzy regulators design. The nonlinear systems are represented by fuzzy models proposed by Takagi and Sugeno. The stability analysis and the design of controllers axe described by LMIs (Linear Matrix Inequalities), that can be solved efficiently using convex programming techniques.

Ultrasonic density measurement cell design and simulation of non-ideal effects

This paper presents a theoretical analysis of a density measurement cell using an unidimensional model composed by acoustic and electroacoustic transmission lines in order to simulate non-ideal effects. The model is implemented using matrix operations, and is used to design the cell considering its geometry, materials used in sensor assembly, range of liquid sample properties and signal analysis techniques. The sensor performance in non-ideal conditions is studied, considering the thicknesses of adhesive and metallization layers, and the effect of residue of liquid sample which can impregnate on the sample chamber surfaces. These layers are taken into account in the model, and their effects are compensated to reduce the error on density measurement. The results show the contribution of residue layer thickness to density error and its behavior when two signal analysis methods are used. (c) 2006 Elsevier B.V. All rights reserved.

Less Conservative Control Design for Linear Systems with Polytopic Uncertainties via State-Derivative Feedback

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Design of a Takagi-Sugeno Fuzzy Regulator for a Set of Operation Points

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Experimental damage detection grammian matrix

Structural Health Monitoring (SHM) has diverse potential applications, and many groups work in the development of tools and techniques for monitoring structural performance. These systems use arrays of sensors and can be integrated with remote or local computers. There are several different approaches that can be used to obtain information about the existence, location and extension of faults by non destructive tests. In this paper an experimental technique is proposed for damage location based on an observability grammian matrix. The dynamic properties of the structure are identified through experimental data using the eigensystem realization algorithm (ERA). Experimental tests were carried out in a structure through varying the mass of some elements. Output signals were obtained using accelerometers.

Observer-based state-feedback versus H-infinity output feedback control solved by LMI approach for applications in smart structures

This paper aims with the use of linear matrix inequalities approach (LMIs) for application in active vibration control problems in smart strutures. A robust controller for active damping in a panel was designed with piezoelectrical actuators in optimal locations for illustration of the main proposal. It was considered, in the simulations of the closed-loop, a model identified by eigensystem realization algorithm (ERA) and reduced by modal decomposition. We tested two differents techniques to solve the problem. The first one uses LMI approach by state-feedback based in an observer design, considering several simultaneous constraints as: a decay rate, limited input on the actuators, bounded output peak (output energy) and robustness to parametic uncertainties. The results demonstrated the vibration attenuation in the structure by controlling only the first modes and the increased damping in the bandwidth of interest. However, it is possible to occur spillover effects, because the design has not been done considering the dynamic uncertainties related with high frequencies modes. In this sense, the second technique uses the classical H. output feedback control, also solved by LMI approach, considering robustness to residual dynamic to overcome the problem found in the first test. The results are compared and discussed. The responses shown the robust performance of the system and the good reduction of the vibration level, without increase mass.

Optimal and robust modal control of a flexible structure using an active dynamic vibration absorber

This paper is concerned with feedback vibration control of a lightly damped flexible structure that has a large number of well-separated modes. A single active electrical dynamic absorber is used to reduce a particular single vibration mode selectively or multiple modes simultaneously. The absorber is realized electrically by feeding back the structural acceleration at one position to a collocated piezoceramic patch actuator via a controller consisting of one or several second order lowpass filters. A simple analytical method is presented to design a modal control filter that is optimal in that it maximally flattens the mobility frequency response of the target mode, as well as robust in that it works within a prescribed maximum control spillover of 2 dB at all frequencies. Experiments are conducted with a free-free beam to demonstrate its ability to control any single mode optimally and robustly. It is also shown that an active absorber with multiple such filters can effectively control multiple modes simultaneously.

Ovarian structure and hormonal status of the UChA and UChB adult rats in response to ethanol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crystal structure of human purine nucleoside phosphorylase complexed with acyclovir

In human, purine nucleoside phosphorylase (HsPNP) is responsible for degradation of deoxyguanosine and genetic deficiency of this enzyme leads to profound T-cell mediated immunosuppression. PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation and has been submitted to extensive structure-based drug design. This work reports the first crystallographic Study of human PNP complexed with acyclovir (HsPNP:Acy). Acyclovir is a potent clinically useful inhibitor of replicant herpes simplex virus that also inhibits human PNP but with a relatively lower inhibitory activity (K-i=90muM). Analysis of the structural differences among the HsPNP:Acy complex, PNP apoenzyme, and HsPNP:Immucillin-H provides explanation for inhibitor binding, refines the purine-binding site, and can be used for future inhibitor design. (C) 2003 Published by Elsevier B.V.

Crystal structure of human PNP complexed with guanine

Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. PNP is a target for inhibitor development aiming at T-cell immune response modulation and has been submitted to extensive structure-based drug design. More recently, the 3-D structure of human PNP has been refined to 2.3 Angstrom resolution, which allowed a redefinition of the residues involved in the substrate-binding sites and provided a more reliable model for structure-based design of inhibitors. This work reports crystallographic study of the complex of Human PNP:guanine (HsPNP:Gua) solved at 2.7 Angstrom resolution using synchrotron radiation. Analysis of the structural differences among the HsPNP:Gua complex, PNP apoenzyme, and HsPNP:immucillin-H provides explanation for inhibitor binding, refines the purine-binding site, and can be used for future inhibitor design. (C) 2003 Elsevier B.V. All rights reserved.