Filtered gradient active fuzzy neural network noise control in an enclosure backed by a clamped plate

The performance of conventional linear algorithms in active noise control applications deteriorates facing nonlinearities in the system mainly because of loudspeakers. On the other hand, fuzzy logic and neural networks are good candidates to overcome this drawback. In this paper, the acoustic attenuation of noise in a rectangular enclosure with a flexible panel and five rigid walls is presented both theoretically and experimentally using filtered gradient fuzzy neural network (FGFNN) error back propagation algorithm in which the secondary path effect is implemented in derivation of updating rules. Considering this effect in updating rules leads to faster convergence and stability of the active noise control system. On the other hand, the primary path in the investigated system comprises an identified nonlinear model of loudspeaker inside the aforementioned box, parameters of which vary with the input current. The loudspeaker is identified using series‐parallel neural network model identification method. As a comparison, the performance of filtered‐x least mean squares and FGFNN algorithms are compared. It is observed that FGFNN controller exhibits far better results in the presence of loudspeakers with nonlinear behavior in primary path.Copyright © 2012 John Wiley & Sons, Ltd.     

Ionic strength and composition affect the mobility of surface-modified Fe0 nanoparticles in water-saturated sand columns

The surfaces of nanoscale zerovalent iron (NZVI) used for groundwater remediation must be modified to be mobile in the subsurface for emplacement. Adsorbed polymers and surfactants can electrostatically, sterically, or electrosterically stabilize nanoparticle suspensions in water, but their efficacy will depend on groundwater ionic strength and cation type as well as physical and chemical heterogeneities of the aquifer material. Here, the effect of ionic strength and cation type on the mobility of bare, polymer-, and surfactant-modified NZVI is evaluated in water-saturated sand columns at low particle concentrations where filtration theory is applicable. NZVI surface modifiers include a high molecular weight (MW) (125 kg/mol) poly(methacrylic acid)-b-(methyl methacrylate)-b-(styrene sulfonate) triblock copolymer (PMAA-PMMA-PSS), polyaspartate which is a low MW (2-3 kg/mol) biopolymer, and the surfactant sodium dodecyl benzene sulfonate (SDBS, MW = 348.5 g/mol). Bare NZVI with an apparent zeta-potential of -30 +/- 3 mV was immobile. Polyaspartate-modified nanoiron (MRNIP) with an apparent zeta-potential of -39 +/- 1 mV was mobile at low ionic strengths (< 40 mM for Na+ and < 0.5 mM for Ca2+), and had a critical deposition concentration (CDC) of approximately 770 mM Na+ and approximately 4 mM for Ca2+. SDBS-modified NZVI with a similar apparent zeta-potential (-38.3 +/- 0.9 mV) showed similar behavior (CDC approximately 350 mM for Na+ and approximately 3.5 mM for Ca2+). Triblock copolymer-modified NZVI had the highest apparent zeta-potential (-50 +/- 1.2 mV), the greatest mobility in porous media, and a CDC of approximately 4 M for Na+ and approximately 100s of mM for Ca2+. The high mobility and CDC is attributed to the electrosteric stabilization afforded by the triblock copolymer but not the other modifiers which provide primarily electrostatic stabilization. Thus, electrosteric stabilization provides the best resistance to changing electrolyte conditions likely to be encountered in real groundwater aquifers, and may provide transport distances of 10s to 100s of meters in unconsolidated sandy aquifers at injection velocities used for emplacement.     

Prediction of fatigue life in cold expanded Al-alloy 2024-T3 plates used in double shear lap joints

To predict fatigue crack initiation and fatigue crack growth lives in cold expanded double shear lap joints a numerical method has been employed. The total estimated fatigue lives were compared with available experimental fatigue test results for plain hole and cold expanded hole specimens of Al 2024-T3 in double shear lap joints. Three-dimensional finite element simulations have been performed in order to obtain the created residual stresses field due to cold expansion and subsequent far field longitudinal loading in the double shear lap joint. The obtained stress and strain distributions from the finite element analyses were employed to predict stress concentration factors to calculate fatigue crack initiation and fatigue crack growth lives using AFGROW computer code. The predicted fatigue lives demonstrate that there is a good agreement between the proposed method and experimental fatigue test results.     

Automatic selection and fusion of color spaces for image thresholding

Automatic selection of color models has a great significance for machine vision purposes like image segmentation, object recognition, etc. Typically, selection of a proper color model is a problem that can just solve by testing the models on the target one by one. To achieve a proper color model, in this article, we propose a new method which is shaped on the basis of clustering and relation among models. The proposed method is verified experimentally for two different images (in thresholding purpose). The experimental results show that this method has a suitable power for automatic purposes.     

Semantic image classification by genetic algorithm using optimised fuzzy system based on Zernike moments

Image classification is a challenging problem of computer vision. This study reports a fuzzy system to semantic image classification. As it is a complex task, various information of digital image, including three color space components and two Zernike moments with different order, are gathered and utilized as an input of fuzzy inference system to materialize a robust rotation/lighting condition and size invariant image classifier. For better performance, all the membership functions are optimized by genetic algorithm after empirical design stage. 90.62 and 96.25 % classification rates for RGB and HSI color spaces confirm the reliability of optimized system in different image conditions given in this contribution.     

D‐Lactate production as a function of glucose metabolism in Saccharomyces cerevisiae

Methylglyoxal, a reactive, toxic dicarbonyl, is generated by the spontaneous degradation of glycolytic intermediates. Methylglyoxal can form covalent adducts with cellular macromolecules, potentially disrupting cellular function. We performed experiments using the model organism Saccharomyces cerevisiae, grown in media containing low, moderate and high glucose concentrations, to determine the relationship between glucose consumption and methylglyoxal metabolism. Normal growth experiments and glutathione depletion experiments showed that metabolism of methylglyoxal by log‐phase yeast cultured aerobically occurred primarily through the glyoxalase pathway. Growth in high‐glucose media resulted in increased generation of the methylglyoxal metabolite d ‐lactate and overall lower efficiency of glucose utilization as measured by growth rates. Cells grown in high‐glucose media maintained higher glucose uptake flux than cells grown in moderate‐glucose or low‐glucose media. Computational modelling showed that increased glucose consumption may impair catabolism of triose phosphates as a result of an altered NAD⁺:NADH ratio. Copyright © 2013 John Wiley & Sons, Ltd.     

Material bead deposition with 2 + 2 ½ multi-axis machining process planning strategies with virtual verification for extruded geometry

Process planning for hybrid manufacturing, where additive operations can be interlaced with machining operations, is in its infancy. New plastic- and metal-based hybrid manufacturing systems are being developed that integrate both additive manufacturing (AM) and subtractive (machining) operations. This introduces new process planning challenges. The focus of this research is to explore process planning solution approaches when using a hybrid manufacturing approach. Concepts such as localized AM build ups, adding stock to a CAD model or section for subsequent removal, and machining an AM stock model are investigated and illustrated using virtual simulations. A case study using a hybrid laser cladding process is used to demonstrate the opportunities associated with a hybrid solution. However, unlike machining, the process characteristics from system to system vary greatly. These are portrayed via a high power, high material deposition feed rate laser cladding system. There are unique challenges associated with AM processes and hybrid manufacturing. New tools and design rules need to be developed for this manufacturing solution to reach its potential.     

Ultrasonication study for suspending single-walled carbon nanotubes in water

A systematic calorimetry-based technique was developed to standardize single-walled carbon nanotube (SWNT) dispersion protocol. Simple calorimetric experiments were performed to benchmark the performance of the ultra-dismembrator. Temperature profiles for the sonication period were utilized to estimate energy input to the system. Energy loss profile was generated for the ultradismembrator in use and a calibration relationship was formulated that could standardize the sonication process. The standardized protocol was used to prepare aqueous SWNT suspensions-sonicating SWNTs in a varied range of input energy (18-100 kJ) in water. SWNT mass fractions suspended for each energy input was accurately measured and the suspended SWNT samples were characterized for morphology, surface potential, cluster size and structure, and chemical functionality using high resolution transmission electron microscopy (HRTEM), electrophoresis, dynamic and static light scattering (DLS/SLS), and Raman spectroscopy. The study demonstrated that suspended mass of SWNTs increased up to 18 kJ of energy input with no further increase upon continued energy input. The physicochemical properties showed similar trend for energy input. The aggregate cluster size, surface potential behavior, as well as the Raman defect properties plateaued after the initial energy input. The significant changes observed were limited to morphological properties, i.e., shorter length, debundled, and sharp edged SWNTs and fractal cluster formation (lower D(f)) with increased input energy.     

Finding the Kool Mixx: how Brown & Williamson used music marketing to sell cigarettes

Objective

To describe the history of Kool''s music‐themed promotions and analyse the role that music played in the promotion of the brand.

Methods

Analysis of previously secret tobacco industry documents, legal documents, and promotional materials.

Results

Brown & Williamson started Kool sponsorship of musical events in 1975 with Kool Jazz concerts. Music was considered to be an effective marketing tool because: (1) music helped consumers make emotional connections with the brand; (2) music concerts were effective for targeted marketing; (3) music tied together an integrated marketing campaign; and (4) music had potential to appeal widely to a young audience. Brown & Williamson''s first music campaigns successfully targeted young African‐American male audiences. Subsequent campaigns were less effective, exploring different types of music to achieve a broader young adult appeal.

Conclusions

This case study suggests Brown & Williamson used music most successfully for targeted marketing, but they failed to develop a wider audience using music because their attempts lacked consistency with the Kool brand''s established identity. The 2004 “Kool Mixx” campaign both returned to Brown & Williamson''s historic practice targeting young African‐American males, and also exploited a musical genre with much more potential to bring Kool more universal appeal, as hip‐hop music is increasingly popular among diverse audiences. Tobacco control efforts led by African‐American community activists to oppose these marketing strategies should continue; expanding these coalitions to include the hip‐hop community may further increase their effectiveness.     

Extreme Toughening of Soft Materials with Liquid Metal

Soft and tough materials are critical for engineering applications in medical devices, stretchable and wearable electronics, and soft robotics. Toughness in synthetic materials is mostly accomplished by increasing energy dissipation near the crack tip with various energy dissipation techniques. However, bio‐materials exhibit extreme toughness by combining multi‐scale energy dissipation with the ability to deflect and blunt an advancing crack tip. Here, we demonstrate a synthetic materials architecture that also exhibits multi‐modal toughening, whereby embedding a suspension of micron sized and highly deformable liquid metal (LM) droplets inside a soft elastomer, the fracture energy dramatically increases by up to 50x (from 250 ± 50 J m^‐2 to 11,900 ± 2600 J m^‐2) over an unfilled polymer. For some LM‐embedded elastomer (LMEE) compositions, the toughness is measured to be 33,500 ± 4300 J m^‐2, which far exceeds the highest value previously reported for a soft elastic material. This extreme toughening is achieved by (i) increasing energy dissipation, (ii) adaptive crack movement, and (iii) effective elimination of the crack tip. Such properties arise from the deformability of the LM inclusions during loading, providing a new mechanism to not only prevent crack initiation, but also resist the propagation of existing tears for ultra tough, soft materials.