Dependence of thickness on the withdrawal speed for SiO2 and TiO2 coatings obtained by the dipping method

SiO₂ and TiO₂ sol-gel thin films were prepared from solutions of different concentration. To fit the experimental coating thickness values, the modification of two theoretical equations, available from the literature, was used. The best-fit results were given by the approach which relates the thickness to the square root of the velocity. It was shown that, provided the same heat treatment is used for the films, the thickness of coatings obtained from solutions of different concentration and at any withdrawal speed may be predicted from just one thickness value obtained at one withdrawal speed, if the solutions' viscosity and density, are known.     

New precursor for the post-synthesis preparation of Fe-ZSM-5 zeolites with low iron content

A new method for preparing ZSM-5 catalysts containing highly dispersed iron species is presented. Iron(III) oxalate was used as the iron precursor in an aerobic aqueous exchange process. The presence of different iron species inside the zeolite pores was investigated by IR spectroscopy of adsorbed NO, which revealed an excellent iron dispersion. The results were compared with those obtained on a Fe-ZSM-5 catalysts prepared by iron(II) chloride sublimation and on samples prepared by controlled migration of framework iron in isomorphously substituted samples.     

Rapid prototyping: Applications in academic institutions and industry

In today's competitive world, the manufacturers have to get a new and improved product to the market as fast as possible to be able to compete in the global market. The major obstacle for this task had been a long product development cycle, i.e., design, prototype manufacture and testing. The introduction of rapid prototyping (RP) in the early stages of product development has greatly reduced the development time frame and cost involved in prototype manufacturing. Furthermore, RP applications are growing very fast in such a way that it is now possible to produce parts not as prototypes, but as final parts to be used in several engineering applications. Thus, RP is now acting as a bridge to help designers, manufacturing engineers, marketing and sales personnel to provide goods timely to the customer. This paper discusses practices, current developments and future trends of RP. This paper also discusses the use and role of RP in academic institutions.     

IR studies of CO and NO adsorbed on well characterized oxide single microcrystals

A systematic investigation of the surface morphology and of the vibrational properties of CO and NO adsorbed on simple oxides microcrystals (like MgO, NiO, NiO-MgO, CoO-MgO, ZnO, ZnO-CoO, -Cr₂O₃, -Al₂O₃, MgAl₂O₄ and other spinels, TiO₂, ZrO₂ and other oxides of a similar structure) with regular crystalline habit and exposing thermodynamically stable and neutral faces, is presented with the aim to elucidate the spectroscopic manifestations of CO and NO adsorbed on well defined crystallographic positions.

In particular the structure of CO and NO adsorbed on the cationic sites of extended faces of these model solids is presented and discussed with the aim of elucidating the nature of the Me^x+··· CO/NO bond (Me^x+ = non transition metal ion or transition metal ion). When non transition metal ions are involved, the molecule-cation interaction is predominantly electrostatic. This leads to an increase of the CO stretching frequency, which is roughly proportional to the polarizing field. On the contrary, when transition metal ions are involved, beside the predominant electrostatic interactions, a small contribution to the bond stability comes also from d-π overlap forces, which, although not very important from the energetic point of view, greatly influence the static and dynamic dipoles localized on the adsorbed molecules. Consequently, the strength of the dipole-dipole interactions occurring in the ordered adlayers of CO and NO adsorbed on transition and non transition metal oxide surfaces are resulted remarkably different.

On these well defined surfaces, the effects influencing the half-width (FWHM) of the CO and NO stretching peaks have also been considered. It has been calculated that the FWHM is a very sensitive parameter of the surface perfection. In a few cases (ZnO, -Cr₂O₃, etc.) FWHM values comprised in the 1.5–3.7 range have been obtained, which are indicative of a single-crystal quality of the exposed faces. These spectroscopic results were compared with those obtained with quantum calculations.

Finally the activity towards CO and NO of perfect, low index faces and of more defective situations (like those associated with edges, steps and corners) are compared, in order to have a better insight on the role of surface defectivity in catalytic reactions.     

Phenolic Profile of Peanut By-products: Antioxidant Potential and Inhibition of Alpha-Glucosidase and Lipase Activities

Free, esterified, etherified and insoluble‐bound phenolics from three samples, namely meal from whole peanuts (MWP), meal from dry‐blanched peanuts (MDBP) and peanut skin (PS) were evaluated for their total phenolic content (TPC), and phenolic profile using HPLC–DAD–ESI–MSⁿ. The TPC was in the order of PS > MWP > MDBP. Among 37 compounds identified 10 were reported for peanuts for the first time. Proanthocyanidins were detected in peanut skin and MWP, but not in MDBP. The presence of peanut skin in MWP rendered up to 9.8‐fold higher scavenging activity towards the DPPH radical as compared with MDBP. Phenolics from all samples and fractions showed inhibition of alpha‐glucosidase and lipase activities, which are key enzymes involved in the absorption of glucose and triacylglycerols, respectively. Therefore, their antioxidant properties as well as their potential role in the management of diabetes and obesity makes them worthy of further consideration as functional food ingredients.     

Hardware-In-the-Loop Simulation with X-Plane of Attitude Control of a SUAV Exploring Atmospheric Conditions

The attitude control law for fixed-wing small unmanned aircraft proposed in this paper is constructed based on two phases of a flight: stable flight and maneuvering flight. In the maneuvering flight, the aircraft deflects the main control surfaces (ailerons and elevator), whereas on the stable flight only the trim tabs are deflected. The switch between the two flights is done when the aircraft enters a zone in which the difference between the aircraft’s attitude and the reference value that the airplane needs to reach is greater than a predetermined value. The control laws are implemented on an on-board computer and are validated though Hardware-In-the-Loop (HIL) simulations, between the hardware and the flight simulator X-Plane, which simulates the unmanned aircraft dynamics, sensors, and actuators. The paper proves that this implementation can reduce the rise time and the overshoot, compared with traditional PID implementations. In order to analyze the behavior of the SUAV in these situations, it was performed simulations with Wind Gust and levels of Turbulence, using the X-Plane features.     

An IMU/UWB/Vision-based Extended Kalman Filter for Mini-UAV Localization in Indoor Environment using 802.15.4a Wireless Sensor Network

Indoor localization of mobile agents using wireless technologies is becoming very important in military and civil applications. This paper introduces an approach for the indoor localization of a mini UAV based on Ultra-WideBand technology, low cost IMU and vision based sensors. In this work an Extended Kalman Filter (EKF) is introduced as a possible technique to improve the localization. The proposed approach allows to use a low-cost Inertial Measurement Unit (IMU) in the prediction step and the integration of vision-odometry for the detection of markers nearness the touchdown area. The ranging measurements allow to reduce the errors of inertial sensors due to the limited performance of accelerometers and gyros. The obtained results show that an accuracy of 10 cm can be achieved.     

Ultrastructural features of the myotendinous junction of the sternomastoid muscle in Wistar rats: From newborn to aging

The myotendinous junction (MTJ) is a major area for transmitting force from the skeletal muscle system and acts in joint position and stabilization. This study aimed to use transmission electron microscopy to describe the ultrastructural features of the MTJ of the sternomastoid muscle in Wistar rats from newborn to formation during adulthood and possible changes with aging. Ultrastructural features of the MTJ from the newborn group revealed pattern during development with interactions between muscle cells and extracellular matrix elements with thin folds in the sarcolemma and high cellular activity evidenced through numerous oval mitochondria groupings. The adult group had classical morphological features of the MTJ, with folds in the sarcolemma forming long projections called “finger‐like processes” and sarcoplasmic invaginations. Sarcomeres were aligned in series, showing mitochondria near the Z line in groupings between collagen fiber bundles. The old group had altered “finger‐like processes,” thickened in both levels of sarcoplasmic invaginations and in central connections with the lateral junctions. We conclude that the MTJ undergoes intense activity from newborn to its formation during adulthood. With increasing age, changes to the MTJ were observed in the shapes of the invaginations and “finger‐like processes” due to hypoactivity, potentially compromising force transmission and joint stability. Microsc. Res. Tech. 75:1292–1296, 2012. © 2012 Wiley Periodicals, Inc.     

Evaluation of the Mn(II) adsorption potential of SiO2 obtained by different wet chemical methods

This paper describes the development of SiO₂ by 2 different wet chemical methods: polymeric precursor (PP) and sol-gel (SG). These samples were used as adsorbents of Mn(II) metal ions. Physicochemical characteristics of the 2 adsorbents were established, while zeta potential, Scanning Electron Microscopy, and Brunauer-Emmett-Teller (BET) surface area methods were further employed for characterization. Efficiencies of the prepared adsorbents in the adsorption of Mn(II) from aqueous solutions were investigated. The BET surface areas of the prepared adsorbent were 171 and 7 m² g⁻¹ for SiO₂ PP and SiO₂ SG, respectively. Optimal adsorption occurred at pH 8.5, 5g L⁻¹ of adsorbent concentration, and 90 minutes of contact time for both adsorbents. The Langmuir and Freundlich isotherms models fitted the experimental data of SiO₂ PP and SiO₂ SG, respectively, and SiO₂ PP showed the highest adsorption capacity due, probably, to its greater specific area.     

Bovine milk powder adulteration with vegetable oils or fats revealed by MALDI-QTOF MS

Matrix-assisted laser desorption/ionisation-quadrupole time of flight mass spectrometry (MALDI-QTOF MS) allowed detection of bovine milk powder adulteration with vegetable oils or fats with high speed and reliability, requiring little sample preparation (n-hexane extraction) and no prior separation procedures. This technique was also able to identify the adulterated employed in this fraud. Hydrogenated soybean oil addition in bovine milk powder sample generate a similar TAG profile to that observed on adulterated milk samples apprehended by the Brazilian Federal Police. In this sense, a robust method for high throughput forensic screening of milk powder adulteration by exogenous oils and fats is showed.