Fault Estimation for a Quad-Rotor MAV Using a Polynomial Observer

This work addresses the problem of fault detection and diagnosis (FDD) for a quad-rotor mini air vehicle (MAV). Actuator faults are considered on this paper. The basic idea behind the proposed method is to estimate the faults signals using the extended state observers theory. To estimate the faults, a polynomial observer (Aguilar et al. 2011; Mata-Machuca et al., Commun Nonlinear Sci Numer Simul 15(12):4114–4130, 2010, BioSystems 100(1):65–69, 2010) is presented by using the available measurements and know inputs of the system. In order to investigate the diagnosability properties of the system, a differential algebra approach is proposed (Cruz-Victoria et al., J Frankl Inst 345(2):102–118, 2008; and Martinez-Guerra and Diop, IEE P-Contr Theor Ap 151(1):130–135, 2004). The effectiveness of the methodology is illustrated by means of numerical simulations.     

Proposal of a New G-BOP Test to Evaluate Cracks in Weld Beads in Thin Sheets

The objective of the present work is the evaluation of a proposal for a gapped bead-on-plate (G-BOP) test, used for study of hydrogen cracks in relatively thin sheets of welded steel. That new proposal consists of the replacement of the usual solid blocks by an assembly of blocks in such a way that the test can evaluate weld beads on thin sheets. Student t distribution is applied to examine the functionality of the proposed test. Weld metals were deposited with flux-cored wires E71T-1 and E71T8-K6, with diameters of 1.6 and 1.7 mm, respectively, under two different preheating temperatures. Metal susceptibility to hydrogen cracking was evaluated by the presence and percentage of cracks in the weld metal. In order to evaluate and verify the functionality of the new G-BOP test proposal, the following were examined: efficiency of the new test in inducing hydrogen cracks in the weld metal, result replicability, fracture modes present in cracks, and the cooling rate imposed on the welding zone. Results showed that the new G-BOP test proposal is viable; results were replicable and the test was efficient in inducing cracks in weld metal with a confidence of 90%.     

Interferometric colours produced by anodised aluminium diffraction grating

Highly ordered dimple arrays that give rise to bright structural colours with a rainbow distribution have been fabricated by means of etidronic acid anodising and subsequent selective oxide dissolution. High-purity aluminium samples were anodised at 270?V and 313?K and after removing the alumina porous film, highly ordered structures were obtained with two different cell diameters, namely 701?±?43 and 655?±?36?nm. These highly ordered near-subwavelength structures fabricated on the aluminium surface induced an optical effect for surface colorisation that could be predicted by interferometric equations. The generated angle-dependent colours were investigated. The mathematically predicted colours agree well with the reflected measured colours.     

Transformation superplasticity in Zircadyne 705

The zirconium alloy Zircadyne 705 (main alloying addition: 2.5 wt.% Nb) was thermally cycled from 900 °C (100% β-phase) to 710 °C (80% α-phase and 20% β-phase), resulting in strain increments after each cycle that are linearly proportional to stress up to 2 MPa. Tensile elongations in excess of 240% were achieved without fracture. The Newtonian flow behavior and high ductility indicate that transformation superplasticity is the dominant deformation mechanism. The superplastic strain increment decreases as the cycling amplitude and period decrease, in general agreement with existing transformation superplasticity models. This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium was organized by Daniel G. Sanders, The Boeing Company.     

On the capacitance-voltage modeling of strained quantum-wellMODFETs

A theoretical model for the capacitance-voltage characteristics of strained modulation-doped field-effect transistors (MODFETs) is developed, based on a self-consistent solution of the Schrodinger and Poisson equations. We report on the first MODFET C-V simulator in which the proposed Hamiltonian takes into account the strain caused by lattice mismatch, as well as the position-dependent lattice constant and electron effective mass. It is demonstrated that the inclusion of strain-related energy terms is essential to achieve good agreement between theory and experimental data for the C-V characteristics of pseudomorphic-channel devices at high gate voltages. The model is also shown to be a useful tool to predict important device characteristics such as the transconductance     

Hepatocarcinogenesis Prevention by Pirfenidone Is PPARγ Mediated and Involves Modification of Nuclear NF-kB p65/p50 Ratio

Targeted therapies for regulating processes such as inflammation, apoptosis, and fibrogenesis might modulate human HCC development. Pirfenidone (PFD) has shown anti-fibrotic and anti-inflammatory functions in both clinical and experimental studies. The aim of this study was to evaluate PPARγ expression and localization in samples of primary human tumors and assess PFD-effect in early phases of hepatocarcinogenic process. Human HCC tissue samples were obtained by surgical resection. Experimental hepatocarcinogenesis was induced in male Fischer-344 rats. TGF-β1 and α-SMA expression was evaluated as fibrosis markers. NF-kB cascade, TNFα, IL-6, and COX-2 expression and localization were evaluated as inflammation indicators. Caspase-3, p53, and PARP-1 were used as apoptosis markers, PCNA for proliferation. Finally, PPARα and PPARγ expression were evaluated to understand the effect of PFD on the activation of such pathways. PPARγ expression was predominantly localized in cytoplasm in human HCC tissue. PFD was effective to prevent histopathological damage and TGF-β1 and α-SMA overexpression in the experimental model. Anti-inflammatory effects of PFD correlate with diminished IKK and decrease in both IkB-phosphorylation/NF-kB p65 expression and p65-translocation into the nucleus. Pro-apoptotic PFD-induced effects are related with p53 expression, Caspase-3 p17 activation, and PARP-1-cleavage. In conclusion, PFD acts as a tumor suppressor by preventing fibrosis, reducing inflammation, and promoting apoptosis in MRHM.     

Fluid Flow Characteristics of String Reactors Packed with Spherical Particles

A hydrodynamic investigation of three geometries of string pellet reactors filled with spheres was conducted. Two geometries were circular spiral channels, while the third was a straight horizontal square channel. Stimulus‐response experiments provided data for residence time distribution analysis from which Pe numbers and liquid holdup were deduced. Flow regimes and transitions were determined from visual observations through the transparent tube wall. For the whole range of the experimental conditions applied in this work and for all reactors, the ratio of gas to liquid velocities, V_g/V_l, is a controlling parameter for Pe number, holdup, and pressure drop.     

Merging the Versatile Functionalities of Boronic Acid with Peptides

Peptides inherently feature the favorable properties of being easily synthesized, water-soluble, biocompatible, and typically non-toxic. Thus, boronic acid has been widely integrated with peptides with the goal of discovering peptide ligands with novel biological activities, and this effort has led to broad applications. Taking the integration between boronic acid and peptide as a starting point, we provide an overview of the latest research advances and highlight the versatile and robust functionalities of boronic acid. In this review, we summarize the diverse applications of peptide boronic acids in medicinal chemistry and chemical biology, including the identification of covalent reversible enzyme inhibitors, recognition, and detection of glycans on proteins or cancer cell surface, delivery of siRNAs, development of pH responsive devices, and recognition of RNA or bacterial surfaces. Additionally, we discuss boronic acid-mediated peptide cyclization and peptide modifications, as well as the facile chemical synthesis of peptide boronic acids, which paved the way for developing a growing number of peptide boronic acids.