Development of a wide range-operable,rich-lean low-NOx combustor for NH3 fuel gas-turbine power generation

Low-NOx NH₃-air combustion power generation technology was developed by using a 50-kWe class micro gas-turbine system at the National Institute of Advanced Industrial Science and Technology (AIST), Japan, for the first time. Based on the global demand for carbon-free power generation as well as recent advances involving gas-turbine technologies, such as heat-regenerative cycles, rapid fuel mixing using strong swirling flows, and two-stage combustion with equivalence ratio control, we developed a low-NOx NH₃-air non-premixed combustor for the gas-turbine system. Considering a previously performed numerical analysis, which proved that the NO reduction level depends on the equivalence ratio of the primary combustion zone in a NH₃-air swirl burner, an experimental study using a combustor test rig was carried out. Results showed that eliminating air flow through primary dilution holes moves the point of the lowest NO emissions to the lesser fuel flow rate. Based on findings derived by using a test rig, a rich-lean low NOx combustor was newly manufactured for actual gas-turbine operations. As a result, the NH₃ single fueled low-NOx combustion gas-turbine power generation using the rich-lean combustion concept succeeded over a wide range of power and rotational speeds, i.e., below 10–40 kWe and 75,000–80,000?rpm, respectively. The NO emissions were reduced to 337?ppm (16% O₂), which was about one-third of that of the base system. Simultaneously, unburnt NH₃ was reduced significantly, especially at the low electrical power output, which was indicative of the wider operating range with high combustion efficiency. In addition, N₂O emissions, which have a large Global Warming Potential (GWP) of 298, were reduced significantly, thus demonstrating the potential of NH₃ gas-turbine power generation with low environmental impacts.     

Lactococcus lactis catalyses electricity generation at microbial fuel cell anodes via excretion of a soluble quinone

Lactococcus lactis is a gram-positive, normally homolactic fermenter that is known to produce several kinds of membrane associated quinones, which are able to mediate electron transfer to extracellular electron acceptors such as Fe³⁺, Cu²⁺ and hexacyanoferrate. Here we show that this bacterium is also capable of performing extracellular electron transfer to anodes by utilizing at least two soluble redox mediators, as suggested by the two-step catalytic current developed. One of these two mediators was herein suggested to be 2-amino-3-dicarboxy-1,4-naphthoquinone (ACNQ), via evaluation of standard redox potential, ability of the bacterium to exploit the quinone when exogenously provided, as well as by high performance liquid chromatography coupled with UV spectrum analysis. During electricity generation, L. lactis slightly deviated from its normal homolactic metabolism by excreting acetate and pyruvate in stoichiometric amounts with respect to the electrical current. In this metabolism, the anode takes on the role of electron sink for acetogenic fermentation. The finding that L. lactis self-catalyses anodic electron transfer by excretion of redox mediators is remarkable as the mechanisms of extracellular electron transfer by pure cultures of gram-positive bacteria had previously never been elucidated.     

Short synthesis of alkyl-substituted acenes using carbonyl-directed C-h and C-o functionalization

A convenient method for the synthesis of tetraalkylanthracenes and -pentacenes by means of ruthenium-catalyzed regioselective C-H alkylation of the corresponding acenequinones was developed. Dialkyldiarylpentacene was also synthesized using chemoselective tandem C-H alkylation/C-O arylation of dimethoxypentacenequinone. It was suggested that a tetraalkylpentacene is stable under air in the dark and possesses an appropriate HOMO level as active material for p-type organic field-effect transistors (OFETs).     

Toward Ultralow‐Bandgap Liquid Crystalline Semiconductors: Use of Triply Fused Metalloporphyrin Trimer–Pentamer as Extra‐large π‐Extended Mesogenic Motifs

In contrast with their dimeric homologue, triply fused zinc porphyrin trimer–pentamer, as extra‐large π‐extended mesogens, assemble into columnar liquid crystals (LCs) when combined with 3,4,5‐tri(dodecyloxy)phenyl side groups ( 3 P_Zn – 5 P_Zn , Figure 1 ). Their LC mesophases develop over a wide temperature range, namely, 41–280 °C (on heating) for 5 P_Zn , and all adopt an oblique columnar geometry, typically seen in columnar LC materials involving strong mesogenic interactions. These LC materials are characterized by their wide light‐absorption windows from the entire visible region up to a near infrared (NIR) region. Such ultralow‐bandgap LC materials are chemically stable and serve as hole transporters, in which 5 P_Zn gives the largest charge carrier mobility (2.4×10^?2 cm V^?1 s^?1) among the series. Despite a big dimensional difference, they coassemble without phase separation, in which the resultant LC materials display essentially no deterioration of the intrinsic conducting properties.     

Unique and faithful embeddings of projective-planar graphs

A graph G is uniquely embeddable in a surface F² if for any two embeddings f₁,f₂: G → F², there exists an isomorphism σ: G → G and a homeomorphism h: F² → F² for which h → f₁ = f₂ σ. A graph G is faithfully embeddable in a surface F² if G admits an embedding f: G → F² such that for any isomorphism σ: G → G, there is a homeomorphism h: F² → F² with h → f = f → σ. It will be shown that if a projective-planar graph G is 5-connected and contains a subdivision of the complete graph K₆ as its subgraph, then G is uniquely embeddable in a projective plane, and that moreover if G is not isomorphic to K₆, then G is faithfully embeddable in a projective plane.     

Anomalous volumetric behavior of water-hexane and water-decane mixtures in the vicinity of the critical region as studied by infrared spectroscopy

Infrared spectra of binary mixtures of water with hexane and decane were measured at temperatures and pressures in the 473-648 K and 70-350 bar ranges, respectively. Volumetric concentrations of water and the hydrocarbons in the mixtures were obtained from absorption intensities of the fundamental OH stretching band of HDO and combination transitions of the hydrocarbons. Using both the concentrations, densities of the aqueous mixtures were estimated and compared with densities before mixing, which were calculated using literature densities of the neat liquids. It is found that anomalously large volume expansion on mixing occurs in the vicinity of the critical region of the mixtures.     

Total Synthesis of Mallotusinin

The total synthesis of mallotusinin, which bears a tetrahydroxydibenzofuranoyl (THDBF) bridge between the 2-oxygen and 4-oxygen of glucose on corilagin with a 3,6-O-(R)-hexahydroxydiphenoyl (HHDP) bridge, is described. The key features of the total synthesis are: 1) improvements of our previously reported method to synthesize corilagin; 2) establishment of the THDBF skeleton via an unusual intramolecular S_NAr reaction of an HHDP analogue, and 3) the application of a two-step bislactonization strategy for a HHDP bridge construction into the 2,4-O-THDBF bridge. Oxidative phenol coupling of 1,2,4-orthoacetyl-3,6-di-(4-O-benzylgalloyl)-α-d -glucopyranose and the orthoester cleavage of the coupling product without the pyranose-furanose ring transformation are key reactions for the improved synthesis of corilagin, which enabled the adequate supply of a corilagin precursor that was required to develop the mallotusinin synthesis. These established methods are expected to help develop the synthesis of other ellagitannins with a bridge between the two oxygens of corilagin.     

Diphenyl phosphate/4‐dimethylaminopyridine as an efficient binary organocatalyst system for controlled/living ring‐opening polymerization of L‐lactide leading to diblock and end‐functionalized poly(L‐lactide)s

The ring‐opening polymerizations (ROPs) of ε‐caprolactone (ε‐CL) and L ‐lactide (LLA) have been studied using the organocatalysts of diphenyl phosphate (DPP) and 4‐dimethylaminopyridine (DMAP). The “dual activation” property of DPP and the “bifunctional activation” property of DPP/DMAP were confirmed by the NMR measurement for ε‐CL and its chain‐end model of poly(ε‐caprolactone) and for LLA and its chain‐end model of poly(L ‐lactide) (PLLA), respectively. The molar ratio of DPP/DMAP was optimized as 1/2 for the ROP of LLA leading to the well‐defined PLLA, such as the molecular weight determined from ¹H NMR measurement of 19,200 g mol^?1 and the narrow polydispersity of 1.10. Additionally, functional initiators were utilized for producing the end‐functionalized PLLAs. The DPP‐catalyzed ROPs of ε‐CL and its analogue cyclic monomers and then the DPP/DMAP‐catalyzed ROP of LLA produced block copolymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1047–1054