Integrated design of agricultural and industrial processes: A case study of combined sugar and ethanol production

Bioethanol production from molasses has advantages in greenhouse gas emissions because of its energy acquisition from bagasse. However, the improvement of bioethanol productivity is challenging; while each elemental technology option can be greatly improved, the trade‐offs between the production of raw sugar and bioethanol are complex. This issue should be addressed through the optimization of the whole system, including both agricultural and industrial processes. In this study, we constructed a model of combined raw sugar and bioethanol production from sugarcane considering agricultural and industrial technology options. Data were acquired through a detailed investigation of actual sugar mills. Case studies on the redesign of combined raw sugar and bioethanol production demonstrated that the simultaneous implementation of both technology options increases production of food, materials, and energy from plant‐derived renewable resources, thus demonstrating the effectiveness of the interdisciplinary approach. © 2016 American Institute of Chemical Engineers AIChE J, 63: 560–581, 2017     

Electroreduction of cation-deficient oxide and dioxygen at a passive iron electrode

The electrochemical characterization of the cation-deficient Fe₂O₃ or passive film with adsorbed oxygen atoms has been given which was produced on iron under the strongly oxidizing conditions of higher potentials. The reduction potential of the cation-deficient Fe₂O₃ lay about 0.5 V anodic to that of the ordinary passive film on iron. The reduction of dioxygen has been studied at a rotating platinum ring-passive iron disk electrode. The passive film was first reduced to porous intermediate [Fe(OH)₂]_ads, and dioxygen was reduced by a four electron process on a film (Fe₃O₄)-covered iron.     

Growth of a Bonelike Apatite Layer on a Substrate by a Biomimetic Process

A dense and uniform bonelike apatite layer was formed on a substrate by the following biomimetic method. The substrate was first placed on granular particles of CaO, SiO₂-based glass soaked in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma and then soaked in another fluid highly supersaturated with respect to the apatite. The thickness of the apatite layer increased in proportion to the soaking time in the second solution. The rate of increase in the thickness of the apatite layer increased from 0.5 to 7.0 μm/day with increasing temperature of the second solution from 10° to 60°C, increased from 0.15 to 1.7 μm/day with increasing ion concentrations of the second solution from 0.2 to 1.5 times those of the SBF, and doubled by shaking the second solution. These results indicate that the growth of the apatite layer is controlled by mass transport across the interface between the crystal and the fluid.     

Hydrothermal Soft Chemical Synthesis and Particle Morphology Control of BaTiO3 in Surfactant Solutions

Barium titanate (BaTiO₃) particles with book-like and spherical morphology were prepared by using a hydrothermal soft chemical process in the presence of a cationic surfactant. A layered titanate of H_1.07Ti_1.73O₄ with a lepidocrocite-like structure and plate-like particle morphology was used as the precursor. The layered titanate was hydrothermally treated in a Ba(OH)₂–(HTMA-OH) ( n -hexadecyltrimethylammonium hydroxide) solution or a Ba(OH)₂–(HTMA-Br) ( n -hexadecyltrimethylammonium bromide) solution in a temperature range of 80°–250°C to prepare BaTiO₃. The intercalation reaction of HTMA⁺ with the layered titanate promotes the structural transformation reaction from the layered titanates to BaTiO₃, while it inhibits the structural transformation reaction to anatase under the hydrothermal conditions. The particle morphology of BaTiO₃ prepared by this method dramatically changes with changing reaction conditions. HTMA⁺ plays an important role in changing particle morphology in the hydrothermal soft chemical process.     

Detection and response characteristics of giant magnetostrictive/piezoelectric laminated cantilevers under cyclic bending

We examine the detection and response characteristics of giant magnetostrictive/piezoelectric laminated cantilevers under cyclic bending in a combined numerical and experimental approach. The laminate is fabricated using thin Terfenol-D and PZT layers. Three-dimensional finite element analysis was conducted, and the dynamic electromagneto-mechanical fields in the two-layered magnetostrictive/piezoelectric laminate were predicted by introducing a second-order magnetoelastic constant of Terfenol-D. The tip deflection, induced voltage, and induced magnetic field were also measured, and experimental data were compared with numerical simulations to verify the model. The effects of load ratio and frequency on the dynamic electromagneto-mechanical fields were then discussed in detail. The finite element method is shown to be capable of estimating the dynamic electromagneto-mechanical fields in the giant magnetostrictive/piezoelectric laminated cantilevers, making it a useful tool for designing future electronic devices with self-sensing or energy harvesting capabilities.     

Active Sites and Mechanism of Oxygen Reduction Reaction Electrocatalysis on Nitrogen‐Doped Carbon Materials

The oxygen reduction reaction (ORR) is a core reaction for electrochemical energy technologies such as fuel cells and metal–air batteries. ORR catalysts have been limited to platinum, which meets the requirements of high activity and durability. Over the last few decades, a variety of materials have been tested as non‐Pt catalysts, from metal–organic complex molecules to metal‐free catalysts. In particular, nitrogen‐doped graphitic carbon materials, including N‐doped graphene and N‐doped carbon nanotubes, have been extensively studied. However, due to the lack of understanding of the reaction mechanism and conflicting knowledge of the catalytic active sites, carbon‐based catalysts are still under the development stage of achieving a performance similar to Pt‐based catalysts. In addition to the catalytic viewpoint, designing mass transport pathways is required for O₂. Recently, the importance of pyridinic N for the creation of active sites for ORR and the requirement of hydrophobicity near the active sites have been reported. Based on the increased knowledge in controlling ORR performances, bottom‐up preparation of N‐doped carbon catalysts, using N‐containing conjugative molecules as the assemblies of the catalysts, is promising. Here, the recent understanding of the active sites and the mechanism of ORRs on N‐doped carbon catalysts are reviewed.     

Tribological properties of a perfluoropolyether lubricant with 3-phenylpropyl functional group for hard disk media

A new perfluoropolyether lubricant (LUB-A) with a 3-phenylpropyl functional group at both ends of the main chain was designed and synthesized by the authors for use in hard disk media, and its tribological performance was evaluated. Time-of-flight secondary ion mass spectrometry showed that LUB-A film on the disk lost none of its functional groups even after a 672 h exposure at 23 °C and 55% RH, although AM3001 lost 94% of its (3,4-dioxomethylenephenyl)methyl functional groups after the same period of exposure. It was found that cyclotriphosphazene (X-1P) was more than four times more soluble in 2 nm thick LUB-A film than in AM3001 film. The degradation ratio of read-back signals in the seek test was less than 5% over a wide range of X-1P content in LUB-A film and no micro-phase separation was induced, in contrast to AM3001 film that could not keep the degradation ratio at less than 5% without inducing micro-phase separation. LUB-A also showed better migration properties at 80 °C and 3% RH than AM3001. LUB-A was proved to be more chemically stable and to show better tribological performance than the currently popular AM3001 when it was used as a thin film mixed with X-1P.     

Potential of hydrolyzed oxymethylene dimethyl ether for the suppression of fuel crossover in polymer electrolyte fuel cells

Fuel crossover is a crucial issue for polymer electrolyte fuel cells (PEFCs) supplied directly with liquid fuels. Therefore, finding a type of fuel with a low fuel crossover rate is required. In this study, we investigated fuel crossover characteristics for oxymethylene dimethyl ether (OME), which has attracted attention for use in engines, and compared it with methanol. Cell performance tests and exhaust gas analyses showed that fully hydrolyzed OME (h-OME), which consisted of methanol and formaldehyde, yields high cell performance at high fuel concentrations, due to the low fuel crossover rate, compared with a direct methanol fuel cell (DMFC). To clarify a factor suppressing fuel crossover, h-OME's effective diffusion coefficient in the membrane was measured. Although an effective diffusion coefficient for fuels like methanol commonly increases with increased fuel's concentration, h-OME's effective diffusion coefficient decreased with increased fuel concentration, leading to a low fuel crossover rate at high h-OME concentrations.     

Effect of Anti-Encrustation Additives on Zirconium Molybdate Hydrate

Anti-encrustation additives were mainly investigated in nitric acid solution with zirconium (Zr), molybdenum (Mo), and tellurium (Te) to prevent the encrustation of zirconium molybdate hydrate (ZMH). The ZMH generated by reaction crystallization of Mo and Zr as main fission products has a high adhesion property in spent nuclear fuel reprocessing. In addition, it is reported that Te, which is also one of the fission products, precipitates together with ZMH. Encrustation of precipitates containing Te was effectively prevented by adding molybdenum trioxide (MoO₃) crystals as an anti-encrustation reagent. The encrustation amount was found to be larger than that under the condition of only Zr and Mo without Te. Consequently, it was suggested that the high adhesion property of Te affected the encrustation amount of ZMH.     

Effect of low segregation coefficient on Ga‐doped multicrystalline silicon solar cell performance

High‐quality Ga‐doped ingots are grown in different casting furnaces at optimized growth parameters; 3·5 kg ingots exhibit normal distribution of diffusion lengths along their height with very high diffusion lengths at the center of the ingot. Effective lifetimes as high as 1·1 ms are realized in 10 Ω cm Ga‐doped wafers after proper P‐diffusion and hydrogen passivation. Average effective lifetimes above 400 µs are also realized after P‐diffusion and hydrogen passivation for Ga‐doped wafers cut from 75 kg ingot where the response to P‐diffusion and hydrogen passivation is pronounced. High effective lifetimes are realized over the whole ingot with minimum values of 20 µs at the top of the ingot, indicating the possible use of about 85% of the ingot for solar cell production. Conversion efficiencies above 15·5% were realized in utilizing more than 80% of the ingot. High efficiencies of about 16% were realized in wafers with resistivities higher than 5 Ω cm p ‐type multicrystalline silicon wafers. Copyright © 2005 John Wiley & Sons, Ltd.