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Nematic Liquid Crystal Reorientation at Aqueous-LC Interface for Monitoring Biochemical Interactions by Specific Ions Effects
Get PDFIn this paper, we attempt to show that contacting aqueous solution made of either kosmotropic or chaotropic ions within a certain concentration range can trigger concentrationdependent transitions of the nematic liquid crystal (LC) at the aqueous-LC interface, going from planar to homeotropic. The effects of different ions (both anions and cations) with different concentrations on the LC orientation have thus been investigated. Nearly every ion, irrespective of being chaotrope or kosmotrope, is found to have its critical concentration, and upon reaching this concentration, homeotropic alignment in LC can be induced. Most chaotropic ions, however, induce homeotropic alignment in LC with a much lower critical concentration than their kosmotropic counterparts. Furthermore, the LC ordering transitions are related to the ion types, concentrations, and pH values, as revealed by the polarized light micrographs of LC thin films in contact with various ionic solutions. The homeotropic ordering of LC at the aqueous-LC interfaces upon the addition of kosmotropic ions is attributed to an internal electric field that results from the concentration difference between the interface and the bulk solutions. As a sharp contrast, this internal electric field, together with the ion-induced dipole interaction between the nitrile group of 4-cyano-4’-pentylbiphenyl (5CB) and the chaotropic ions, determines the orientations of LC upon the addition of chaotropic ions. Understanding the underlying mechanism of the ionic phenomena at aqueous-LC interface is of great importance for the design of aqueous-LC interface for detecting interactions involving ions, as the case in biosensing and many important applications
Natural Rubber-Based Ionogels
Get PDFNatural rubber (NR), besides being an abundant renewable resource for the elastomer industry, can be a potential resource for the design of innovative biobased polymer networks. The present work is based on "telechelic" liquid natural rubber oligomers obtained by controlled chemical degradation of NR. The chain ends of such oligomers can then be functionalized (with acrylate functions in the present case) and reacted with multifunctional crosslinkers in order to form networks. What's more, the initial solubility of such thermosetting system in an ionic liquid (IL) can be used for the formulation of ionogels. Such solid networks typically containing 80% of IL were produced, resulting in high ionic conductivity performances. The oligomer chain length was shown to affect IL fragility due to confinement and specific interactions of ions with the host polymer network
Tuning Intermolecular Interaction Between Lignin and Carbon Nanotubes in Fiber Composites – A Combined Experimental and Ab-InitioModeling Study
Get PDFDoping lignin with carbon nanotubes is a promising strategy for cost-effective high-performance carbon fibers. We investigate the intermolecular interaction potential of CNT and organosolv lignin with two main approaches. Experimentally, oxidized purified multiwalled carbon nanotubes (MWCNTs) and beech organosolv lignins and derivatives are analyzed with their Hansen solubility parameters (HSPs) to assess their mutual compatibility. Theoretically, dispersion-corrected density functional theory simulations of the interaction between model molecules and single-walled carbon nanotubes reveal the source of interactions. We find that oxidation enables and enhances the interaction between carbon nanotubes and organosolv lignin experimentally, which is in agreement with the enhanced polar interaction found in the simulations
Energy Release Rate Measurement of Welded Bamboo Joints
Get PDFDouble cantilever beam tests were used to measure the energy release rates of linear vibrational welded moso bamboo joints. The influence of the length of the preserved cracks, the different combinations of the inner and outer bamboo surfaces and the moisture content is studied herein. The experimental compliance method, which is based on linear elastic fracture mechanics and has been shown to be an ideal method, was used to analyze data with the power equation. The results show that the preserved initial crack length does not have a significant effect on the final measured energy release rate, while the moso bamboo combination does affect the properties dramatically. The welded moso bamboo joints with inner-inner surfaces have the highest energy release rate of 122 J/m2. The average energy release of the outer-outer combination was only 102 J/m2. The expansion of the cracks also became easier when the moisture content of the welded joints was 18.5% compared to 4.5% and 10.1%. So the moisture resistance of the welded joints should be duly improved
Microwave Synthesis of Inulin Acetate as Potential Bio-Based Additive for Poly(Vinyl Chloride)
No full textThe paper presents the findings of an experimental study on the microwave synthesis (MW) of inulin acetate and its possible application as bio-additive in poly(vinyl chloride) (PVC). The obtained inulin acetate has been identified and characterized by spectroscopic methods. Advantages of the MW compared with the conventional synthesis were defined. In order to evaluate possible application of the product as bio-based additive for polymers, effect of the inulin ester on PVC behavior and characteristics has been investigated by differential scanning calorimetry (DSC) and deformation upon extension. Experimental results show that in concentration range up to 30.0 wt. % the inulin ester influences positively the properties of PVC causing effect similar to plasticizing one. At concentration over 30 wt.% the ester shows more specific behavior, which will be further investigated. Conclusions about potential application of MW synthesized inulin acetate as bio-based additive for PVC have been drawn
Three-Variable Shifted Jacobi Polynomials Approach for Numerically Solving Three-Dimensional Multi-Term Fractional-Order PDEs with Variable Coefficients
Get PDFIn this paper, the three-variable shifted Jacobi operational matrix of fractional derivatives is used together with the collocation method for numerical solution of three-dimensional multi-term fractional-order PDEs with variable coefficients. The main characteristic behind this approach is that it reduces such problems to those of solving a system of algebraic equations which greatly simplifying the problem. The approximate solutions of nonlinear fractional PDEs with variable coefficients thus obtained by three-variable shifted Jacobi polynomials are compared with the exact solutions. Furthermore some theorems and lemmas are introduced to verify the convergence results of our algorithm. Lastly, several numerical examples are presented to test the superiority and efficiency of the proposed method
A Numerical Investigation of the Effects of Benign Paroxysmal Positional Vertigo on the Balance Function of the Inner Ear
Get PDFA three-dimensional numerical model of the membranous labyrinth of the semicircular canal of the inner ear was established to investigate the effects of canalithiasis of BPPV on the balance function of the inner ear. The movement of otolith particles in the membranous labyrinth was simulated when a person turns his head to a specific position. The effects of otolith movements on the balance function of the inner ear were simulated for different numbers, diameters, and initial positions of otoliths. The simulation results show that the otolith diameter affects the movement duration of otoliths in the membranous labyrinth. The number and diameter of otoliths, the diameter of the membranous labyrinth, and the initial position of the otoliths can cause changes in the pressure difference on both sides of the cupula of the crista ampullaris (cupula). The latent period and onset period are related to the diameter of otolith particles and the position of the head. There is also a correlation between the severity of the disease and the diameter and number of otolith particles
Machining Parameters Optimization of Multi-Pass Face Milling Using a Chaotic Imperialist Competitive Algorithm with an Efficient Constraint-Handling Mechanism
Get PDFThe selection of machining parameters directly affects the production time, quality, cost, and other process performance measures for multi-pass milling. Optimization of machining parameters is of great significance. However, it is a nonlinear constrained optimization problem, which is very difficult to obtain satisfactory solutions by traditional optimization methods. A new optimization technique combined chaotic operator and imperialist competitive algorithm (ICA) is proposed to solve this problem. The ICA simulates the competition between the empires. It is a population-based meta-heuristic algorithm for unconstrained optimization problems. Imperialist development operator based on chaotic sequence is introduced to improve the local search of ICA, while constraints handling mechanism is introduced and an imperialist-colony transformation policy is established. The improved ICA is called chaotic imperialist competitive algorithm (CICA). A case study of optimizing machining parameters for multi-pass face milling operations is presented to verify the effectiveness of the proposed method. The case is to optimize parameters such as speed, feed, and depth of cut in each pass have yielded a minimum total product ion cost. The depth of cut of optimal strategy obtained by CICA are 4 mm, 3 mm, 1 mm for rough cutting pass 1, rough cutting pass 1 and finish cutting pass, respectively. The cost for each pass are 0.4473 US and 1.3576 US. The results obtained with the proposed schemes are better than those of previous work. This shows the superior performance of CICA in solving such problems. Finally, optimization of cutting strategy when the width of workpiece no smaller than the diameter of cutter is discussed. Conclusion can be drawn that larger tool diameter and row spacing should be chosen to increase cutting efficiency
A Novel Quantum Stegonagraphy Based on Brown States
Get PDFIn this paper, a novel quantum steganography protocol based on Brown entangled states is proposed. The new protocol adopts the CNOT operation to achieve the transmission of secret information by the best use of the characteristics of entangled states. Comparing with the previous quantum steganography algorithms, the new protocol focuses on its anti-noise capability for the phase-flip noise, which proved its good security resisting on quantum noise. Furthermore, the covert communication of secret information in the quantum secure direct communication channel would not affect the normal information transmission process due to the new protocol’s good imperceptibility. If the number of Brown states transmitted in carrier protocol is many enough, the imperceptibility of the secret channel can be further enhanced. In aspect of capacity, the new protocol can further expand its capacity by combining with other quantum steganography protocols. Due to that the proposed protocol does not require the participation of the classic channel when it implements the transmission of secret information, any additional information leakage will not be caused for the new algorithm with good security. The detailed theoretical analysis proves that the new protocol can own good performance on imperceptibility, capacity and security
An Image Steganography Algorithm Based on Quantization Index Modulation Resisting Scaling Attacks and Statistical Detection
Get PDFIn view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method, this paper proposes an image steganography algorithm based on quantization index modulation resisting both scaling attacks and statistical detection. For the spatial image, this paper uses the watermarking algorithm based on quantization index modulation to extract the embedded domain. Then construct the embedding distortion function of the new embedded domain based on S-UNIWARD steganography, and use the minimum distortion coding to realize the embedding of the secret messages. Finally, according to the embedding modification amplitude of secret messages in the new embedded domain, the quantization index modulation algorithm is applied to realize the final embedding of secret messages in the original embedded domain. The experimental results show that the algorithm proposed is robust to the three common interpolation attacks including the nearest neighbor interpolation, the bilinear interpolation and the bicubic interpolation. And the average correct extraction rate of embedded messages increases from 50% to over 93% after 0.5 times-fold scaling attack using the bicubic interpolation method, compared with the classical steganography algorithm S-UNIWARD. Also the algorithm proposed has higher detection resistance than the original watermarking algorithm based on quantization index modulation