Pretreatment of <Emphasis Type="Italic">Helianthus tuberosus</Emphasis> residue by flow-through process for production of fermentable sugar

The pretreatment of Helianthus tuberosus residue was studied for fermentable sugar production. The pretreatment was performed by varying the temperature, type of chemical solution, and concentration. Two different catalytic pretreatments using sulfuric acid and aqueous ammonia were operated and compared in a flow-through column reactor system. The flow-through process was required to increase the sugar production yield of biomass. To selectively remove the lignin of biomass and achieve fractionation of hemicellulose in the liquid phase to produce pentose, the flow-through process could be controlled by the pretreatment conditions. Furthermore, the remaining solid underwent enzymatic hydrolysis for hexose production. The mass balances of biomass pretreated with aqueous ammonia and sulfuric acid solution were compared in terms of production of fermentable sugars. The glucose recovery compared to the initial biomass was 71.2% in the pretreatment using aqueous ammonia at 170 °C, and pretreatment using sulfuric acid solution at 150 °C was 52.3%.     

Preparation and properties of emulsifier‐/solvent‐free polyurethane‐acrylic hybrid emulsions for binder materials: Effect of the glycidyl methacrylate/acrylonitrile content

To obtain binder materials, emulsions of emulsifier‐/solvent‐free waterborne polyurethane‐acrylic hybrids with a fixed acrylic monomer content (30 wt %) were prepared in this study. This study focused on the effect of glycidyl methacrylate (GMA)/acrylonitrile (AN) wt % on the shelf stability, mean particle size and viscosity of hybrid emulsion samples, water swelling %/dynamic mechanical thermal properties/mechanical properties of hybrid film samples, and the failure mode and adhesive strength of binder materials prepared in this study. Characterization of the chemical structures of prepolymers, hybrid materials (binder materials), and atmospheric pressure plasma‐treated polyethylene (PE) has been performed by means of Fourier transformed infrared spectroscopy to determine the presence/disappearance/peak intensity change of functional groups. Various properties such as mean particle size, viscosity, T_g, water swelling %, hardness and mechanical properties, and failure mode and adhesive strength for leather/leather, control PE/leather, and plasma‐treated PE/leather were found to be significantly dependent on the weight ratio of GMA/AN. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44497.     

Dissipative structures in a reaction-diffusion system

A transient analysis of reaction-diffusion equations associated with the model reaction of Prigogine and Lefever (Brusselator model), has been performed. For low system lengths and for fixed boundary conditions, steady state solutions with the low amplitude are unstable. For zero flux boundary conditions the multiplicity of symmetric solutions with the same wave number may exist and the majority of them are unstable. The diffusion of initial components induces relaxation oscillations in space for fixed as well as zero flux boundary conditions. The amplitude of the oscillations increases as the diffusion coefficient of the initial component decreases. For conditions of relaxation oscillations the spatial profiles result in single or multiple propagating fronts. High system lengths for both zero flux and periodic boundary conditions, may give rise to a multipeak incoherent wave pattern. For periodic boundary conditions the multiplicity of waves has been observed. Numerical simulation of two-dimensional spatial structures reveals the existence of certain similarities between the one- and two-dimensional cases.     

Poly(ethylene terephthalate) nanocomposite fibers with new organomica via in situ intercalation

Poly(ethylene terephthalate) (PET) nanocomposites with a newly synthesized organomica (C₁₆BIMD‐Mica) were obtained by using the in situ interlayer polycondensation of ethylene glycol with dimethylterephthalic acid. The PET hybrids were melt‐spun to produce monofilaments with various organoclay contents and draw ratios. The thermomechanical properties and morphologies of the PET hybrid fibers were determined using differential scanning calorimetry, thermogravimetric analysis, wide angle X‐ray diffraction, electron microscopy (SEM and TEM), and a universal tensile machine. The XRD analyses and TEM micrographs showed that the levels of exfoliation and intercalation could be controlled by varying the clay content. The thermomechanical properties of the PET hybrid fibers were found to be better than those of pure PET fibers. POLYM. ENG. SCI., 47:1820–1826, 2007. © 2007 Society of Plastics Engineers     

Control of wave formation pattern in self-oscillating gel by addition of hydroquinone in the Belosov-Zhabotinsky reaction solution

Summary We have investigated the effect of solution composition on the pattern of traveling wave formation in self-oscillating gel in which a metal catalyst for the Belousov-Zhabotinsky(BZ) reaction is covalently bonded to the gel matrix. The reaction solution contains all reactants for the BZ reaction except the catalyst. The gel was synthesized by the co-polymerization of N-isopropylacrylamide(NIPAAm) and Ru(bpy)₃²⁺ catalyst monomer. To vary the composition of the environmental solution for the oscillation reaction, we added a small amount of hydroquinone to the BZ solution since hydroquinone is a good reagent inducing a characteristic wave pattern in the BZ type oscillation system. The experimental results show that the pattern of wave formation in the self-oscillating gel is influenced greatly by a change of the environmental condition of the solution composition for the oscillation reaction without other environmental change such as temperature and pH.     

Effect of Iron and Boron Carbide on the Densification and Mechanical Properties of Titanium Diboride Ceramics

The effect of Fe and B₄C on the sintering behavior and mechanical properties of TiB₂ ceramics have been studied. Sintering was performed in an Ar atmosphere at 2000° using attrition-milled TiB₂ powder (mean particle size = 0.8 μm). When a small amount of Fe (0.5 wt%) was added, abnormal grain growth occurred and the sintered density was low. In the case of B₄C added along with 0.5 wt% Fe, however, abnormal grain growth was remarkably suppressed, and the sintered density was increased up to 95% of theoretical. But with excess Fe addition (5 wt%), B₄C grains did not act as a grain growth inhibitor, and B₄C grains were frequently trapped in large TiB₂ grains. The best mechanical properties were obtained for the TiB₂–10 wt% B₄C–0.5 wt% Fe ceramics, which exhibited a three-point bending strength of 400 MPa and a fracture toughness of 5.5 MPa · m^1/2.     

Restricting Answer Candidates Based on Taxonomic Relatedness of Integrated Lexical Knowledge Base in Question Answering

This paper proposes an approach using taxonomic relatedness for answer‐type recognition and type coercion in a question‐answering system. We introduce a question analysis method for a lexical answer type (LAT) and semantic answer type (SAT) and describe the construction of a taxonomy linking them. We also analyze the effectiveness of type coercion based on the taxonomic relatedness of both ATs. Compared with the rule‐based approach of IBM's Watson, our LAT detector, which combines rule‐based and machine‐learning approaches, achieves an 11.04% recall improvement without a sharp decline in precision. Our SAT classifier with a relatedness‐based validation method achieves a precision of 73.55%. For type coercion using the taxonomic relatedness between both ATs and answer candidates, we construct an answer‐type taxonomy that has a semantic relationship between the two ATs. In this paper, we introduce how to link heterogeneous lexical knowledge bases. We propose three strategies for type coercion based on the relatedness between the two ATs and answer candidates in this taxonomy. Finally, we demonstrate that this combination of individual type coercion creates a synergistic effect.     

Identification of the electromechanical material properties of a multilayer ceramic capacitor

A multilayer ceramic capacitor (MLCC) vibrates when an electrical signal containing an alternating current (AC) component is applied to it. The piezoelectric and electrostrictive coefficients of the dielectric layer are needed to analyze such vibrations because both affect the vibration. Also, they must be determined for various direct current (DC) biases because an MLCC is operated with various electrical signals and the coefficients vary as the DC bias changes. We determined the coefficients by measuring the vibration of an MLCC under a range of DC biases. When a single‐frequency AC voltage is applied to an MLCC, it vibrates with both fundamental and second‐harmonic frequencies because of piezoelectricity and electrostriction. These frequencies were measured and separated into their piezoelectric and electrostrictive components to derive the piezoelectric and electrostrictive coefficients. Because of the difficulty of calculating the coefficients, a finite element (FE) method was adopted in consideration of the complicated structure of the MLCC. The derived piezoelectric coefficients were cross‐checked and verified by impact testing. The electrostrictive vibration component was greater than the piezoelectric one except when the applied DC electric field was near zero. This showed that both piezoelectricity and electrostriction must be considered in vibrational analyses of MLCCs.     

Electrically Driven Reversible Phase Changes in Layered In2Se3 Crystalline Film

An unconventional phase‐change memory (PCM) made of In₂Se₃, which utilizes reversible phase changes between a low‐resistance crystalline β phase and a high‐resistance crystalline γ phase is reported for the first time. Using a PCM with a layered crystalline film exfoliated from In₂Se₃ crystals on a graphene bottom electrode, it is shown that SET/RESET programmed states form via the formation/annihilation of periodic van der Waals' (vdW) gaps (i.e., virtual vacancy layers) in the stack of atomic layers and the concurrent reconfiguration of In and Se atoms across the layers. From density functional theory calculations, β and γ phases, characterized by octahedral bonding with vdW gaps and tetrahedral bonding without vdW gaps, respectively, are shown to have energy bandgap value of 0.78 and 1.86 eV, consistent with a metal‐to‐insulator transition accompanying the β‐to‐γ phase change. The monolithic In₂Se₃ layered film reported here provides a novel means to achieving a PCM based on melting‐free, low‐entropy phase changes in contrast with the GeTe–Sb₂Te₃ superlattice film adopted in interfacial phase‐change memory.