Improved holographic particle sizing by using absolute values of the wavelet transform

A new method for sizing particle from in-line particle holograms by using absolute values of the wavelet transform is proposed in order to improve accuracy in measurements. The proposed method provides direct calculation of the particle size by using spatial frequency information of a chirp signal at minima position of an envelope function. Simulation and experimental results are presented.     

Features of crystallization behavior of natural rubber/halloysite nanotubes composites using synchrotron wide-angle X-ray scattering

The correlation between the mechanical strength and the crystallization behavior of natural rubber (NR)/halloysite nanotubes (HNT) composites is discussed. The tensile strength of NR is improved with the addition of HNT. This improvement is attributed to the unique structure of HNT, which facilitates good dispersion and strong interfacial interaction. HNT also play an important role in assisting the strain-induced crystallization of NR. Crystallization under strain is observed using synchrotron wide-angle X-ray scattering. The stress–strain curves and the corresponding degree of crystallinity after straining provide further evidence. Based on these analyses, a mechanistic model for strain-induced crystallization and the evolution of the orientation of the network structure is proposed.     

UNSTEADY ONE-DIMENSIONAL FLOWS OF A VIBRATIONALLY EXCITED GAS

Journal of Applied Mechanics and Technical Physics - Complete group analysis of the system of one-dimensional unsteady equations of the dynamics of a vibrationally excited gas is performed in the...     

Invariant solutions of one-dimensional equations of two-temperature relaxation gas dynamics

The group analysis method is applied to the plane one-dimensional equations of two-temperature gas dynamics. The complete classification of the equations with respect to admitted Lie group is studied. All invariant solutions are analyzed and their comparisons with the known invariant solutions of the ideal gas dynamics system are presented.     

A Protein from Aloe vera that Inhibits the Cleavage of Human Fibrin(ogen) by Plasmin

A protease inhibitor protein with the molecular mass of 11,804.931 Da (analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) was isolated from Aloe vera leaf gel and designated as AVPI-12. The isoelectric point of the protein is about 7.43. The first ten amino acid sequence from the N-terminal was found to be R–D–W–A–E–P–N–D–G–Y, which did not match other protease inhibitors in database searches and other publications, indicating AVPI-12 is a novel protease inhibitor. The band protein of AVPI-12 migrated further on nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) than reducing SDS-PAGE. This result indicated that the molecule of AVPI-12 did not contain interchain disulfide bonds, but appeared to have intrachain disulfide bonds instead. AVPI-12 strongly resisted digestion by the serine proteases human plasmin and bovine trypsin. The protein could protect the γ-subunit of human fibrinogen from plasmin and trypsin digestion, similar to the natural plasma serine protease inhibitor α₂-macroglobulin. The protein also could protect the γ-subunit of fibrinogen from the cysteine protease papain. AVPI-12 also exhibited dose-dependent inhibition of the fibrinogenolytic activity of plasmin, similar to α₂-macroglobulin. The fibrinolytic inhibitory activity of AVPI-12 and the small-angle X-ray scattering showed that the protein could protect human fibrin clot from complete degradation by plasmin. The inhibition of the fibrinogenolytic and fibrinolytic activities of plasmin by AVPI-12 suggests that the inhibitor has potential for use in antifibrinolytic treatment.     

Extraction of object position from in-line holograms by using single wavelet coefficient

A novel digital method for tracking position of objects from in-line holograms by using single wavelet coefficient is proposed. In the proposed method, a wavelet transform is used to analyze the holograms. An axial position of the object being studied is determined by using a real value of a resultant wavelet coefficient appears at a center position of interference fringes. A feasibility of this method is experimentally verified by analyzing holograms of an optical fiber.     

Quality of images decrypted from in-line holographic encryption of images

We investigate quality of images decrypted from in-line holograms recorded with a random phase mask placed behind an input image. High- and low-contrast fingerprint images are used as test scenes. The simulation results show that due to multiple convolution processes and a limitation of the CCD sensor resolution, quality of decrypted images is sensitive to spatial separations between the input image, the phase mask and the hologram. We propose a new method for improving quality of decrypted images by using background noise removal. It is found that in comparison with high-contrast input, the low-contrast image is more robust to distortion caused by the encryption–decryption process.     

Chlorination and characterization of natural rubber and its adhesion to nitrile rubber

Chlorinated natural rubber (CNR) vulcanized sheets were prepared by immersing the NR sheets in sodium hypochlorite solution for various chlorination times ranging from 0 to 30 min. The degree of chlorination as indicated by X-ray Absorption Near-Edge Spectroscopy (XANES) implied that the chlorine content increases with the chlorination time from 0 to 10 min then levels off. Atomic Force Microscopy (AFM) showed an evolution of the surface roughness and stiffness. These two properties increased gradually with chlorination time. The bond strength between CNR and nitrile rubber (NBR) also increased gradually. The data showed cohesive failure beginning at 1 min and extending throughout the 30 min of the study. The maximum peel strength was found at 1 min of chlorination time and decreased afterwards. The decrease in peel strength was caused by the increase in surface stiffness of NR that acted as weak boundary layer. The surface stiffness governed the peel strength between NR and NBR.