Compensated carrier PWM synchronization: a novel method to achieveself-regulation and AC unbalance compensation in AC fed converters

The compensated carrier PWM synchronization (CCPS) method for AC-fed PWM power converters is presented. The method provides a solution to PWM converters fed by industrial power systems (IPSs). Such environments usually present unbalances and magnitude fluctuations of AC voltages. Those circumstances impair standard PWM techniques because low-order harmonics are produced and DC-link regulation is poor. To reduce these undesirable effects produced by IPS, a method based on using independently compensated carriers per phase was conceived. In particular, CCPS prevents second harmonic generation and achieves converter self-regulation. The method can be used with any PWM technique and bidirectional power flow. The evaluation of CCPS is based on a complete performance comparison of a PWM rectifier with and without CCPS for various known PWM techniques     

A form for soliciting the measurement of drug plasma level and its use in a university hospital

The correct clinical use of drug plasma levels is frequently jeopardized by neglecting to consider pharmacokinetic parameters at the time of sample drawing. A form to be filled at this time revealed that inadequate information concerning the drug was present in 28% and sampling time in 50% of cases. Accordingly, a new form is proposed to help avoid this information inadequacies and thus lead to better clinical use of drug plasma levels.     

Molecular Interferometric Imaging for Biosensor Applications

Molecular interferometric imaging (MI2) is a common-path interferometric imaging technique for detecting protein binding to surfaces. The experimental metrology limit is 10 pm/pixel longitudinal resolution at 0.4-mum diffraction-limited lateral resolution, corresponding to 1.7 attogram of protein, which is only 8 antibody molecules per pixel, near to single-molecule detection. The scaling mass sensitivity at the metrology limit is 5 fg/mm. We demonstrate a protein microarray application in a 128-multiplex immunoassay. Assay applications include prostate specific antigen (PSA) at a detection limit of 60 pg/mL and the cytokine interleukin-5 (IL-5) at a detection limit of 50 pg/mL. Realtime binding assays using MI2 enable the study of reaction kinetics of antibodies exposed to antigen, and the binding of antibody Fc regions to protein G.     

Micro-Helicopter for Long-Distance Missions: Description and Attitude Stabilization

This paper presents the development of a micro coaxial helicopter (MCR UAV) whose main characteristic is that it should be carried by an air shuttle transporter and then released in a desired place far away from the launching site, to develop surveillance missions in hover flight. A real-time embedded system is built in order to validate the proposed aerodynamic prototype, and a classic control law based on a classical backstepping procedure for the dynamic system is implemented to test this vehicle in autonomous flight. Finally, simulation and practical results are presented for hover flight.     

Magnifying lens for 800 MeV proton radiography

This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.     

On the adaptive control of robot manipulators with velocity observers

To achieve accurate tracking control of robot manipulators many schemes have been proposed. A common approach is based on adaptive control techniques, which guarantee trajectory tracking under the assumption that the robot model structure is perfectly known and linear in the unknown parameters, while joint velocities are available. Despite tracking errors tend to zero, parameter errors do not unless some persistent excitation condition is fulfilled. There are few works dealing with velocity observation in conjunction with adaptive laws. In this note, an adaptive control/observer scheme is proposed for tracking position of robot manipulators. It is shown that tracking and observation errors are ultimately bounded, with the characteristic that when a persistent excitation condition is matched then they, as well as the parameter errors, tend to zero. Simulation results are in good agreement with the developed theory.     

Dispersion and exfoliation of nanoclays in itaconic acid funcionalized LDPE by ultrasound treatment

Polyethylene–montmorillonite nanocomposites were prepared in the melt applying various ultrasonic powers (231, 347, and 462 W) and temperatures (185, 200, and 215 °C) in the presence of itaconic acid. Dispersion–exfoliation of montmorillonite and in situ low density polyethylene functionalization with itaconic acid were carried out by ultrasound assisted extrusion process. Clay dispersion and exfoliation was evaluated by X‐ray diffraction (XRD) and electronic microscopy (STEM). The degree of grafting itaconic acid into low density polyethylene (LDPE) was determined by infrared analysis (FTIR) and titration technics. Ultrasound‐treated nanocomposites showed improved clay dispersion compared with non‐treated ones. Mechanical properties, XRD, and STEM microscopy indicated that the grafting level, clay dispersion, and exfoliation was directly influenced by IA concentration, temperature, and ultrasonic energy. For instance, the itaconic acid grafted into LDPE was improved from 0.13% to 0.71% when ultrasound power was increased and when temperature was reduced. The modulus was enhanced up to 225 MPa when the ultrasound power was increased up to 462 W. The nanocomposites decomposition temperature, determined by thermogravimetric analysis, was increased nearly 20 °C when 1% w/w itaconic acid was used. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46260.     

Understanding particles emitted from spray and wall-guided gasoline direct injection and flex fuel vehicles operating on ethanol and iso-butanol gasoline blends

Traffic-related pollutants are an ever-growing concern. However, the composition of particle emissions from new vehicle technologies using relevant current and prospective fuel blends is not known. This study tested four current and up-and-coming vehicle technologies with nine fuel blends with various concentrations of ethanol and iso-butanol. Vehicles were driven on both the federal test procedure (FTP) and the unified cycle (UC). Additional tests were conducted under steady-state speed conditions. The vehicle technologies include spray-guided gasoline direct injection (SG-GDI), wall-guided gasoline direct injection (WG-GDI), port-fuel injection flex fuel vehicle (PFI-FFV), and a wall-guided GDI-FFV. The fuels consisted of 10–83% ethanol and 16–55% iso-butanol in gasoline. The composition of soot, water-insoluble mass (WIM), water-soluble organic mass, and water-insoluble organic mass (WIOM), and OM was measured. The majority of emissions over FTP and UC were water-insoluble (>70%), and WIOM contributes mostly to OM. PFIs have lower soot and particulate matter (PM) emissions in comparison to the WG-GDI technology even while increasing the renewable fuel content. SG-GDI technology, which has not penetrated the market, show promise as soot and PM emissions are comparable to PFI vehicles while preserving the GDI fuel economy benefits. The WIM fraction in GDI-FFV consistently increased with increasing ethanol concentration. Lastly, the impact of the future vehicle emissions and traffic pollutants is discussed. SG-GDI technology is found to be a promising sustainable technology to enhance fuel economy and also reduce PM, soot, and WIM emissions.

Copyright © 2017 American Association for Aerosol Research     

Ti/TiSiNO Multilayers Fabricated by Co-sputtering

Multilayer coatings of titanium/ titanium silicon oxynitride (Ti/TiSiNO) were fabricated on stainless steel 434-L substrates by sputtering technique using Ti and TiSiO targets. The multilayers were formed by alternately and simultaneously introducing and suspending a 4-sccm flow of nitrogen together with an interchange of targets, during different time periods of 1.0, 2.0, 3.0 and 4.0 min; thus, we obtained intervals of different thickness by alternating the target (Ti) and using only argon, and later with both targets (Ti + TiSiO) and the two gases (Ar + N₂). The final thickness was within a range of 0.4-0.8 μm, depending on the number of multi layers obtained by means of glow discharge optical emission spectroscopy. The structure, topography, color, durability and nanofriction were analyzed in accordance with the growth parameters used. It was found that the values of hardness depend on the number of layers deposited. The greatest number of layers, 48 of them, was obtained with a time period of 1 min, thereby attaining the maximum value of hardness and the minimum value for both the friction coefficient and the RMS, with 31 GPa, 7.42 × 10^?3 and 0.17 nm, respectively. The phases found correspond to Ti₂N, Si₃N₄, rutile phase of TiO₂ and Ti. The TiO₂ phase was corroborated with Raman dispersion spectroscopy. The color of the coatings was affected by variation in the working pressure, which varied because of the internal process of reactive sputtering.