Design,analysis and testing of a smart fin

The paper presents a design concept for a control fin usually used in airborne vehicles such as UAV’s, Micro UAV’s and missiles. The research presents the design of a smart fin with integral piezoelectric actuators embedded in the airfoil skin. Electric field applied to the actuators would twist the airfoil leading to a change of the angle of attack. The study presents, analyze and demonstrates various lamination and actuation methods including a parametric performance investigation by finite elements models and closed form analytical model. The design and the theoretical results are verified by a manufactured smart wing demonstrator subjected to series of static and dynamic lab tests.     

Zonal flow energy ratio evolution during L-H and H-L transitions in EAST plasmas

The essential role of zonal flow in the L-H transition and the suppression of turbulence have been studied with a long range correlation technique using Langmuir probe arrays in EAST tokamak.Two toroidally localized probe arrays are used to measure the zonal flow during L-H transition and H-L back transition.The energy ratio of the low frequency zonal flow to the total drift wave turbuletce is calculated.During ELM-free H mode,the energy ratio is higher than that in L mode,which reveals the important role of zonal flows in regulating turbulence amplitude in L-H transition.     

Preparative separation of mixtures by mass spectrometry

A specially designed mass spectrometer which allows for preparative separation of mixtures is described. This mass spectrometer allows for large ion currents, on the order of nanoamperes, to be produced by electrospray and transmitted into a high vacuum. Accumulation of nanomole quantities of collected and recovered material in several hours is demonstrated. The use of high-velocity ions reduces space charge effects at high ion currents. Separation of mass occurs simultaneously for all ions, providing a 100% duty cycle. The use of a linear dispersion magnet avoids compression at higher m/z ratios. A deceleration lens slows the ions to allow for soft landing at low kinetic energy. The ions are neutralized by ion pairing on an oxidized metal surface. Retractable landing plates allow for easy removal of the separated components.     

Microstructural evolution of gold–aluminum wire-bonds

The purpose of this study is to understand the morphological changes that occur during annealing of Al–Au wire-bonds, by analyzing the interface region of annealed model wire-bonded samples between 5N (99.999%) Au wires and Al pads. Due to the small length scale of the intermetallic region at the interface of the bond, the analysis was done using scanning/transmission electron microscopy combined with energy dispersive spectroscopy. Samples were prepared using a dual-beam focused ion beam system. Microstructural characterization showed that during annealing, a Au-rich intermetallic region was formed under the bond and at the periphery of the bond. Two types of failures occurred during annealing: crack formation at the bond periphery due to an increase in volume during intermetallic growth and the formation of stresses; and oxidation of the AlAu₄ phase adjacent to the Au ball, which resulted in the formation of continuous cracks between the Au ball and the intermetallic region. The characteristic void-line found inside the intermetallic region played no part in failure that occurred during exposure to elevated temperatures.     

Does the transition to parenthood influence driving?

Most parents remember the first time they drove with a newborn child in the car. Feeling the need to protect the infant, they avoided sharp turns and drove more slowly and carefully than normal. But how long do these behaviors persist? Do parents ultimately revert to their previous driving patterns, or does some of the early protectiveness and caution continue to characterize their driving as their infant grows into a toddler and preschooler? In an attempt to answer these questions, two studies were conducted on parents of young children: a qualitative study consisting of personal interviews (16 parents); and a quantitative study in the form of a national telephone survey (165 parents). The results show that the most dominant reported effect of the transition to parenthood on driving is increased apprehension of traffic crashes and a stronger sense of responsibility. However, these changes were found to influence the reported actual driving behavior of only a portion of the parents. Possible explanations of the findings are discussed.     

Engineering nanostructured porous SiO2 surfaces for bacteria detection via "direct cell capture"

An optical label-free biosensing platform for bacteria detection ( Escherichia coli K12 as a model system) based on nanostructured oxidized porous silicon (PSiO(2)) is introduced. The biosensor is designed to directly capture the target bacteria cells on its surface with no prior sample processing (such as cell lysis). The optical reflectivity spectrum of the PSiO(2) nanostructure displays Fabry-Pe?rot fringes characteristic of thin-film interference, enabling direct, real-time observation of bacteria attachment within minutes. The PSiO(2) optical nanostructure is synthesized and used as the optical transducer element. The porous surface is conjugated with specific monoclonal antibodies (immunoglobulin G's) to provide the active component of the biosensor. The immobilization of the antibodies onto the biosensor system is confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, fluorescent labeling experiments, and refractive interferometric Fourier transform spectroscopy. We show that the immobilized antibodies maintain their immunoactivity and specificity when attached to the sensor surface. Exposure of these nanostructures to the target bacteria results in "direct cell capture" onto the biosensor surface. These specific binding events induce predictable changes in the thin-film optical interference spectrum of the biosensor. Our preliminary studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations. The current detection limit of E. coli K12 bacteria is 10(4) cells/mL within several minutes.     

Influence of capsule shell composition on the performance indicators of hypromellose capsule in comparison to hard gelatin capsules

The purpose of this study was to assess the in vitro performances of “vegetable” capsules in comparison to hard gelatin capsules in terms of shell weight variation, reaction to different humidity conditions, resistance to stress in the absence of moisture, powder leakage, disintegration and dissolution. Two types of capsules made of HPMC produced with (Capsule 2) or without (Capsule 3) a gelling agent and hard gelatin capsules (Capsule 1) were assessed. Shell weight variability was relatively low for all tested capsules shells. Although Capsule 1 had the highest moisture content under different humidity conditions, all capsule types were unable to protect the encapsulated hygroscopic polyvinylpyrrolidone (PVP) powder from surrounding humidity. The initial disintegration for all Capsule 1 occurred within 3?min, but for other types of capsules within 6?min (n?=?18). Dissolution of acetaminophen was better when the deionized water (DIW) temperature increased from 32 to 42?°C in case of Capsule 1, but the effect of temperature was not significant for the other types of capsules. Acetaminphen dissolution from Capsule 1 was the fastest (i.e. >90% in 10?min) and independent of the media pH or contents unlike Capsule 2 which was influenced by the pH and dissolution medium contents. It is feasible to use hypromellose capsules shells with or without gelling agent for new lines of pharmaceutical products, however, there is a window for capsule shells manufacturing companies to improve the dissolution of their hypromellose capsules to match the conventional gelatin capsule shells and eventually replace them.