Rotation-Invariant Texture Classification Using Circular Gabor Wavelets Based Local and Global Features

Rotation-invariant texture classification is one of the most challenging problems in computer vision. This paper presents a new and effective method for rotation-invariant texture classification based on the circular Gabor wavelets. The Gabor representation has been shown to be optimal in the sense of minimizing the joint two-dimensional uncertainty in space and frequency. The circular Gabor filter is completely circularly symmetric. So, the circular Gabor wavelets are constructed to decompose an image into multiple scales （subbands） and are rotation invariant. Two group features can be constructed by the mean and variance of the circular Gabor filtered images, and rotation invariant. The experimental results show that the proposed method has comparatively high correct classification rates.     

Mechanical property enhancement of non‐bonding electrospun mats via adhesive

In the present study, the effect of adhesive on the morphology of different electrospun polymeric mats was investigated. The modification of two polymers, poly(methyl methacrylate) and poly(vinyl chloride), was carried out by blending the polymers with different amounts of poly(butyl acrylate) (PBA) adhesive to investigate the effect of different amounts of adhesive with heat hardener in hybrid mats. The introduction of various concentrations of PBA into different polymer solutions led to the formation of point‐bonded electrospun fibrous mats. Scanning electron microscopy images indicated that point‐bonded polymer/adhesive fibers were uniformly distributed throughout the mats. Fourier transform infrared spectrometry, contact angle measurements and thermogravimetric analysis were used to study the different properties of the hybrid mats. The tensile strength of the blended fibrous electrospun mats was increased effectively. This enhancement of the mechanical properties of the mats due to the presence of adhesive increases the number of potential applications of the electrospun mats, especially for mechanically weak polymers. Copyright © 2012 Society of Chemical Industry     

Potential Chemical Markers for the Identification of Irradiated Sausages

Abstract: Hydrocarbons, gas compounds, and off‐odor volatiles were determined for irradiated (0 or 5 kGy) commercial sausages with different fat contents (16% and 29%) during a 60‐d storage period at 4 °C. Total of 4 hydrocarbons (C14:1, C15:0, C16:2, and C17:1) were detected only in irradiated sausages: the amount of C16:2 was the highest, followed by C17:1, C14:1, and C15:0. The concentrations of hydrocarbons decreased significantly (P < 0.05) with storage, but were still detectable at the end of 60‐d storage. Irradiated sausages produced significantly higher amounts of CO than the nonirradiated ones. CH₄ was detected only in irradiated sausages. Dimethyl disulfide was detected only in irradiated sausages and its concentration decreased significantly (P < 0.05) with storage. Fat content of sausages showed a significant effect on the production and retention of hydrocarbons, gas compounds, and sulfur volatiles in irradiated sausages during storage. Some hydrocarbons (C16:2, C17:1, C14:1, and C15:0), CH₄, and dimethyl disulfide were only found in irradiated sausages indicating that these compounds can be used as potential markers for irradiated sausages.     

Influence of the duty cycle on structural and mechanical properties of oxide layers on Al-1050 by a plasma electrolytic oxidation process

Oxide layers were prepared on Al-1050 substrates by an environmentally friendly plasma electrolytic oxidation process using an alkaline solution of Na₂SiO₃ (8 g/L) and NaOH (3 g/L) as the electrolyte. The effects of three different duty cycles (20%, 40%, and 60%) on the structure and hardness of the oxides were investigated. XRD analysis revealed that the oxides were mainly composed of α-Al₂O₃, γ-Al₂O₃, and mullite. The proportion of each phase depended on various electrical parameters, such as the duty cycle and frequency. The morphology, thickness, and the elemental distribution of the oxides were examined by scanning electron microscopy and energy dispersive spectroscopy. The thicknesses of the oxides were found to vary from 20 μm to more than 60 μm for various duty cycles, when identical treatment durations were used. The oxidation treatment also resulted in good adhesion between the oxide layer and the substrate. SEM images indicated that the oxide layers formed at the 60% duty cycle exhibited relatively coarser surfaces with larger pore sizes and sintering particles, and slower growth rates than did those formed at the 20% duty cycle, under identical treatment durations. The oxides prepared at the 20% duty cycle showed smooth surfaces. The oxides layers were found to improve the micro-hardness of Al-1050. In particular, the oxide layers formed at the 40% duty cycle exhibited relatively better micro-hardness owing to their compact microstructures.     

Investigation of the crystallization process and crystal structure of Si-incorporated GeSb phase-change films

The effect of Si incorporation on the crystallization process and crystal structure of Te-free Sb-rich GeSb was investigated in this study. Si concentrations were controlled to 0, 5.1, 9.3, and 12.8 at.% by controlling the sputtering power of the GeSb alloy target (20:80 at.% for Ge:Sb) and Si target. After film deposition, the crystallization process and crystal structure were investigated. Crystallization temperature increased from 320 to 400 °C and the overall crystallinity was decreased with increasing Si concentration. These were analyzed by sheet resistance measurements after thermal annealing and optical contrast measurements by optical static testing. Glass transition temperatures were calculated and increased from 240 to 285 °C with increasing Si concentration. Considering the proportional relation between the glass transition temperature and crystallization temperature, it is thought that more energy is required for crystallization with increased Si concentration. A study of the crystallization process kinetics was conducted by applying the Johnson–Mehl–Avrami model to the optical static test results, which were carried out under a pseudo-isothermal process. The Avrami coefficient was 4.10 and decreased to 3.18 when the crystallization was generated with increased Si concentration from 0 to 12.8 at.%. Therefore, crystallization speed was thought to decrease with increased Si concentration. Based on the results of crystal structure analysis by XRD and HRTEM, the crystal structure of our Sb-rich GeSb PCM was revealed to be a typical Sb structure, i.e., an A7 hexagonal structure with lattice parameters of a = 4.26 Å and c = 11.45 Å. No crystal phase of Ge or Si was observed and no evidence of the structure change in Sb crystals due to Ge or Si incorporation was observed.     

Stress analysis of a stepped rounded D‐ring with a ratio of H1/H2 = 3.0 under uniform squeeze rate and internal pressure by photoelastic experimental hybrid method

Stresses occurring in a stepped rounded D‐ring designed to have a ratio of H₁/H₂ = 3.0 and compressed to 20% squeeze and pressurized with internal pressures of 0 MPa, 0.98 MPa, 1.96 MPa, 3.92 MPa, 4.9 MPa and 5.89 MPa are analyzed using photoelastic experimental hybrid method. It was observed that when a pressure of 0 MPa and 20% compression are applied, the photoelastic isochromatic fringes of the stepped rounded D‐ring with a ratio of H₁/H₂ = 3.0 were almost symmetrical. However, as the applied internal pressure increased, the circular portion of the D‐ring moved over the step on the front side along the points 1_r–2_r towards the restraining wall of the front side of the groove. During the motion of the circular portion, the space between the restraining wall and the step on the front side was slowly filled; but unlike the D‐ring with a ratio of H₁/H₂ = 1.0 where complete filling occurred earlier before extrusion, complete filling of this space delayed until the portion of the D‐ring near the extrusion gap extruded. It was further noted that an internal pressure of up to 5.89 MPa was required to initiate extrusion in the D‐ring with a ratio of H₁/H₂ = 3.0.     

Improving linear processing systems via flexibility

In this paper we tried to improve a given stochastic processing line which is perfectly balanced. By introducing flexibility to a stochastic processing line, we can achieve the benefit of resource pooling. When we apply priority sequencing to the flexible processing line, we can attain an additional reduction in the mean throughput time. By using the heavy traffic approximation the ratio of improvement from flexibility is shown to be significant. We also considered the set-up time loss due to flexibility and derived the appropriate range in which flexibility outperforms set-up time loss. The result of this paper implies that we should consider the alternative of introducing flexibility to a processing system rather than trying to optimally allocate each segments of jobs and get a balanced processing line.     

Effects of atomic size difference and heat of mixing parameters on the local structure of a model metallic glass system

Atomic size differences between constituting elements and the heat of mixing are key factors in designing a metallic glass system. In this study, the effects of atomic size differences and the heat of mixing on the glass-forming ability and the local structure of metallic glasses were studied via molecular dynamic simulations of an ideal system known as the Lennard-Jones embedded-atom method model. The atomic size difference and the heat of mixing of the system were varied by means of the Lennard-Jones parameters. The glass transition behavior was characterized based on the chemical short-range order and by a Voronoi analysis. Our simulations lead to optimized windows of atomic size differences and heat of mixing parameters for metallic glass-forming of the model system. Both a greater negative heat of mixing and a larger atomic size difference are necessary for the enhancement of the glass-forming ability.     

Silver metallization for microwave device using aerosol deposition

We examined the possibility of using aerosol deposition (AD) as a simple, environmentally friendly and dry metallization process capable of acting as an alternative to the electroless and electroplating methods. Silver thick films were fabricated, their characteristics evaluated, and the factors influencing their growth investigated. As a result, silver thick films were successfully fabricated by AD with high deposition rates (10 μm/min) at room temperature. The resistivity of the as-deposited silver thick films was 8–10 times larger than that of the bulk silver. Post-annealing increased the resistivity of the silver films by approximately 2–3 times compared to that of the bulk silver. Microstructural observations revealed an increase in the connectivity between the silver particles after the heat treatments, which reduced the resistivity of the as-deposited silver films.