There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

1.0. Introduction 4044 2.0. Biomass Chemistry and Growth Rates 4047 2.1. Lignocellulose and Starch-Based Plants 4047 2.2. Triglyceride-Producing Plants 4049 2.3. Algae 4050 2.4. Terpenes and Rubber-Producing Plants 4052 3.0. Biomass Gasification 4052 3.1. Gasification Chemistry 4052 3.2. Gasification Reactors 4054 3.3. Supercritical Gasification 4054 3.4. Solar Gasification 4055 3.5. Gas Conditioning 4055 4.0. Syn-Gas Utilization 4056 4.1. Hydrogen Production by Water−Gas Shift Reaction 4056

/pdf/synthesis-of-transportation-fuels-from-biomass-chemistry-3sckhzoqoz.pdf

Synthesis of transportation fuels from biomass: chemistry, catalysts, and engineering.

Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO 2 , wastewater treatment, in human health, as food additive, and for aquaculture.

/pdf/microalgae-for-biodiesel-production-and-other-applications-a-54vmwufrsu.pdf

Microalgae for biodiesel production and other applications: A review

Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

Biofuels produced from various lignocellulosic materials, such as wood, agricultural, or forest residues, have the potential to be a valuable substitute for, or complement to, gasoline. Many physicochemical structural and compositional factors hinder the hydrolysis of cellulose present in biomass to sugars and other organic compounds that can later be converted to fuels. The goal of pretreatment is to make the cellulose accessible to hydrolysis for conversion to fuels. Various pretreatment techniques change the physical and chemical structure of the lignocellulosic biomass and improve hydrolysis rates. During the past few years a large number of pretreatment methods have been developed, including alkali treatment, ammonia explosion, and others. Many methods have been shown to result in high sugar yields, above 90% of the theoretical yield for lignocellulosic biomasses such as woods, grasses, corn, and so on. In this review, we discuss the various pretreatment process methods and the recent literature that...

http://ucce.ucdavis.edu/files/datastore/234-1388.pdf

Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production

Japanese beech was treated with two-step hot compressed water (first step, 230°C/10 MP/15 min: second step; 270°C/10 MP/15 min) and obtained various cellulose-derived compounds in the second step with relatively high molecular weights were characterized by MALDI-TOF/MS. As a result, cellulose-derived products such as cello-triose, cello-tetraose, cello-pentaose, cello-hexaose, cello-heptaose, cello-octaose, and cello-nonaose, and their dehydrated compounds were identified. In spite of the fact that for these cellulose-derived products, supercritical water treatment in our previous study resulted in the dehydration and fragmentation reactions at the reducing end, two-step hot-compressed water treatment resulted only in dehydration reaction. This suggests that hot-compressed water treatment would be milder than that of supercritical water. These results indicate further that the MALDI-TOF/MS is a powerful tool to analyze the molecular structures of hydrolyzed oligosaccharides and evaluate decomposition pathway of lignocellulosics as treated with hot-compressed water.

Characterization of Oligosaccharides with MALDI-TOF/MS Derived from Japanese Beech Cellulose as Treated by Hot-Compressed Water

We study an electron distribution under a quasiperiodic potential in light of hyperuniformity, aiming to es-tablish a classiﬁcation and analysis method for aperiodic but orderly density distributions realized in, e.g., quasicrystals. Using the Aubry-Andr´e-Harper model, we ﬁrst reveal that the electron-charge distribution changes its character as the increased quasiperiodic potential alters the eigenstates from extended to localized ones. While these changes of the charge distribution are characterized by neither multifractality nor translational-symmetry breaking, they are characterized by hyperuniformity class and its order metric. We ﬁnd a nontrivial relationship between the density of states at the Fermi level, a charge-distribution histogram, and the hyperuniformity class. The change to a different hyperuniformity class occurs as a ﬁrst-order phase transition except for an electron-hole symmetric point, where the transition is of the third order. Moreover, we generalize the hyperuniformity order metric to a function, to capture more detailed features of the density distribution, in some analogy with a generalization of the fractal dimension to a multifractal one.

http://link.aps.org/pdf/10.1103/PhysRevResearch.4.033241

Quantum phase transition between hyperuniform density distributions

/pdf/hydrocarbon-fuels-from-palm-oil-through-hydrolysis-followed-1yxvbypm0t.pdf

Hydrocarbon Fuels from Palm Oil through Hydrolysis Followed by Oxidative Cleavage and Decarboxylation

Pyrolysis behavior of cellulose was studied at relatively low pyrolysis temperature (below 280°C, under nitrogen). This paper focuses on the reducing end-group in cellulose as a potential reactive site. Number of the reducing end-group could be reduced down to 17% in Avicel PH-101 by heat treatment with glycerol. Thermal glycosylation occurred between the reducing end-groups and hydroxyl groups of glycerol. With this cellulose (named as G-cellulose) as a model with less reducing end-groups, influences of the reducing end-groups on color formation and weight-loss behavior were studied. Color formation was significantly inhibited in G-cellulose. Initial weight-loss in thermogravimetric (TG) analysis was also reduced. Thus, these low temperature phenomena were suggested to arise from the reducing end-groups in cellulose. Furthermore, pyrolysis studies of the cellulose – methyl-β-D-glucopyrnoside (Me-β-Glc) mixture implied that the reducing end-groups activate the transglycosylation reactions for Me-β-Glc. This may be involved in the initial weight-loss in TG analysis.

Some Low-Temperature Phenomena of Cellulose Pyrolysis

This is a preliminary investigation on the hydrolysis behavior of cotton linter (Gosspium hirstum L.) in different crystalline forms. Celluloses I, II, IIII and IVI were therefore prepared from cotton linter and treated by one-step semi-flow hot-compressed water (HCW) at 270°C/10MPa/15min. As a result, it was found that celluloses I, II, IIII and IVI were decomposed and liquefied in HCW in respective yields of 66.0, 90.4, 74.6 and 94.4wt%. The hydrolyzed products recovered mainly consisted of various cello-saccharides such as glucose and cello-oligosaccharides. In addition, some dehydrated and fragmented compounds as well as organic acids were produced. The highest yields of these decomposed products were realized in the hydrolysis of these various celluloses, and the hydrolysis resistance dependable on its crystalline form was found to be in the following order: cellulose I>cellulose IIII>cellulose II>cellulose IVI. This line of evidence can clearly reveal the effect of different crystalline structures of cellulose on its hydrolysis behavior.

Shiro Saka

Papers

Characterization of Oligosaccharides with MALDI-TOF/MS Derived from Japanese Beech Cellulose as Treated by Hot-Compressed Water

Quantum phase transition between hyperuniform density distributions

Hydrocarbon Fuels from Palm Oil through Hydrolysis Followed by Oxidative Cleavage and Decarboxylation

Some Low-Temperature Phenomena of Cellulose Pyrolysis

Hydrolysis Behavior of Various Crystalline Celluloses from Cotton Linter as Treated by One-Step Semi-flow Hot-Compressed Water