Preparation of ordered macroporous platinum and palladium powders

Ordered macroporous platinum and palladium metal powders were prepared with a combination of silica template and hydrogen reduction methods. The effects of species of metal precursor and calcination of silica templates on the structure of final metal powders were investigated. Precursor of platinum or palladium was infiltrated into closely packed silica templates prepared from tetraethyl orthosilicate and vacuum dried at room temperature following hydrogen reduction to obtain metal–silica complexes. After the removal of the silica templates from the complexes by hydrofluoric acid treatment, metal powders were obtained. Ordered macroporous platinum and palladium powders were obtained by using hydrogen hexachloroplatinate (IV) hexahydrate with uncalcined silica template and palladium (II) chloride with calcined templates, respectively. Composition analyses indicated that silica templates were completely removed from the ordered metal powder. Sizes of the voids in the ordered macroporous metal powders were controlled in the range of 240–520 nm corresponding to those of the silica spheres used.     

Fabrication and photoactivities of spherical-shaped BiVO4 photocatalysts through solution combustion synthesis method

Spherical-shaped BiVO₄ photocatalysts were prepared by the solution combustion synthesis method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), nitrogen absorption for the BET specific surface area, field emission scanning electron microscopy (FE-SEM) and ultraviolet–visible diffraction reflection spectroscopy (UV–vis). The BiVO₄ crystallites show a monoclinic structure with diameter of about 400–600 nm. UV–vis diffusion absorption spectra indicate that the band gap absorption edge of pure BiVO₄ crystallites prepared by the SCS method and the SSR method are 523 nm and 540 nm, corresponding to the band gap energies of 2.45 eV and 2.40 eV, respectively. It is also found that the photocatalytic activity of degradation of methylene blue improves when the molar ratio of fuels to oxidizer is 5.     

Lipid Classes,Fatty Acid Distributions and Triacylglycerol Molecular Species of Broad Beans (<Emphasis Type="Italic">Vicia faba</Emphasis>)

Seed oils from four legume cultivars of Vicia faba, grown in Japan, were extracted and classified by thin-layer chromatography (TLC) into eight fractions. The major lipid components were triacylglycerols (TAG: 48.8–50.1%) and phospholipids (PL: 47.5–50.5%), while hydrocarbons (HC), steryl esters (SE), free fatty acids (FFA), diacylglycerols (1,3- and 1,2-DAG) and monoacylglycerols (MAG) were present in minor proportions (1.8–2.4%). All lipid samples had high amounts of total unsaturated FA, representing 79.7–82.8% and 77.6–79.7% for TAG and PL, respectively. Molecular species and FA distributions of TAG, isolated from the total lipids in the broad beans, were analyzed by a combination of argentation-TLC and GC. Fourteen different molecular species were detected. With a few exceptions, the main TAG components were S₂D (6.1–8.9%), SD₂ (7.8–10.5%), SMT (6.3–8.5%), M₂D (4.5–6.2%), MD₂ (18.9–21.8%), D₃ (21.0–23.9%) and MDT (8.1–10.2%) (where S, M, D, and T denote a saturated fatty acid, a monoene, a diene, and a triene, respectively). These results suggest that the lipid classes, FA distributions and TAG molecular species of broad beans are not dependent on the cultivation areas during the growing season.     

Effect of washing of barium titanate powders synthesized by hydrothermal method on their sinterability and piezoelectric properties

BaTiO₃ (BT) powders were synthesized by the hydrothermal method for fabricating lead-free barium titanate piezoelectric ceramics. The obtained powders were washed by distilled water and 0.01N acetic acid solutions separately, and utilized to obtain piezoelectric ceramics by traditional sintering. BT ceramics with the highest piezoelectric properties (d₃₃ value is over 190 pC/N) was obtained from the BT powder synthesized at 250 °C and washed by acetic acid solution. The influence of washing method and sintering temperature on the piezoelectric properties of BT ceramics were studied. The reasons were investigated by comparing the properties of BT powders and their compacts sintered at different temperature.     

Anomalous molecular orientation of isotactic polypropylene sheet containing N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide

Small amount of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide as a β-form nucleating agent is dissolved beyond 280 °C in a molten isotactic polypropylene (iPP) and appears as needle crystals around at 240 °C during cooling procedure. Further, iPP molecules crystallize on the surface of the needle crystals, in which c-axis of the β-form iPP crystals grows perpendicular to the long axis of the needle crystals. Under flow field at extrusion processing, the needle crystals orient to the flow direction prior to the crystallization of iPP. As a result, c-axis of the β-form iPP crystals orients perpendicular to the applied flow direction with a small amount of α-form iPP. Moreover, the vertical molecular orientation of the extruded sheet sample is responsible for unique mechanical anisotropy; the fracture occurs along the transversal direction.     

One-dimensional salen-type heterospin trimetallic (3d–4f–3d′) chain-like coordination polymers: Syntheses,crystal structures and magnetic properties

Three one-dimensional (1D) heterospin trimetallic chain-like polymers [{LCu(H₂O)}Ln(MeOH)(H₂O)₂{(μ-CN)₂Fe(CN)₄}]·2H₂O (1, Ln = La; 2, Ln = Nd; 3, Ln = Gd) were prepared by substitution of the nitrato ligands in [LCuLn] complexes with [Fe(CN)₆]^3? ions (H₂L = N,N′-bis(3-methoxysalicylidene)propane-1,2-diamine). Single-crystal X-ray diffraction analysis revealed that the methyl on the salen-type ligand impeded the connection between cyanide groups and Cu(II) ions efficiently. Consequently, three novel one-dimensional (1D) trimetallic chain-like polymers were obtained with the linker [Fe(CN)₆]^3? ions interacting only with the lanthanide ions. The magnetic investigation for 3 indicated a ferrimagnetic chain may form.     

Surface Potential of Poly(lactic acid) Composites Containing Calcium Carbonates in Simulated Body Fluid

The surface of a poly(lactic acid) composite (CCPC) containing calcium carbonate was reported to show apatite formation in simulated body fluid (SBF) within 24 h at 37°C. In the present work, ζ potentials of CCPC were examined to determine the rapid apatite formation mechanism at an early stage after soaking in SBF. The ζ potentials of CCPC showed negatively charged values in SBF. The potential decreased immediately after soaking, and subsequently increased during 1–6 h of soaking. After 6–9 h of soaking, no change in ζ potentials was observed. Laser Raman spectroscopy results suggested that the change in the ζ potential is closely related to the amount of Ca²⁺-coordinated carboxy groups on the CCPC surface. The concentration of phosphate ion in SBF decreased after 6 h. Apatite formation was suggested to begin after 6–9 h of soaking via Ca²⁺ coordination to carboxy groups and the subsequent adsorption of phosphate ions.     

Chemical engineering for the Anthropocene

The environmental and resource crises that confront human life on earth demand changes to the whole socio-economic metabolic system. The changes will affect all aspects of life, including the practice of chemical engineering. The historical association of the profession with the fossil carbon economy means that the expertise that makes up chemical engineering must be re-examined and repurposed urgently if the discipline is to play a full role in the socio-economic transition. In this article, we review the historical development of chemical engineering to identify its unique features and find ways in which it can change to meet the challenge. A pattern of 30-year cycles in the development of the discipline is revealed, showing the way it has built up by incorporating approaches from other disciplines and also developing a unique set of skills and knowledge. Chemical engineering as taught needs to prepare graduates to operate under the kind of social contract embodied in declarations by professional bodies. We propose ways in which the expertise comprising chemical engineering can be applied in the ‘just transition’ to a less unsustainable society, including new approaches to plant and process design and also applications ‘outside the pipe’ to environmental modelling and industrial ecology. The unsustainability crisis results from a history of poor public and private decisions, so examination of the different types of decisions is timely. Specific roles for chemical engineers in deliberative decision processes are identified, including enhanced emphasis on risk and precaution.     

Characterization of the biosynthesis gene cluster for alkyl-O-dihydrogeranyl-methoxyhydroquinones in Actinoplanes missouriensis

A polyketide biosynthesis gene cluster (agq) was found on the genome of a rare actinomycete, Actinoplanes missouriensis. Streptomyces lividans expressing agqA encoding a type III polyketide synthase produced alkylresorcinols mainly from C(16-17) fatty acids. Heterologous expression of the agq genes in S. lividans indicated the function of cognate polyketide modification enzymes; a monooxygenase AgqB hydroxylates the alkylresorcinols to yield 6-alkyl-2-hydroxyhydroquinones, a methyltransferase AgqC catalyzes O-methylation of the alkyl-hydroxyhydroquinones to yield 6-alkyl-2-methoxyhydroquinones, and a UbiA-like prenyltransferase AgqD attaches a prenyl group to the C-4 hydroxy group of the alkyl-methoxyhydroquinones to yield 6-alkyl-4-O-geranyl-2-methoxyhydroquinones and 6-alkyl-4-O-dihydrofarnesyl-2-methoxyhydroquinones derived from C(16-17) fatty acids. In contrast, A. missouriensis was found to produce 6-alkyl-4-O-dihydrogeranyl-2-methoxyhydroquinones derived from C(16-18) fatty acids by the function of the agq gene cluster. All of these prenylated phenolic lipids were novel compounds.