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The present work aims at exploring a new hydrolysis approach using sequential combinations of organic acid [oxalic acid (OA)] and base [tetramethylammonium hydroxide (TMAH)] to convert lignocellulosic biomass at mild conditions (150-215 °C, 1-2 h, and 1 atm N 2 ) using a spruce wood sample in a batch reactor. In the single-step tests, hydrolysis with OA can convert biomass to yield sugars and furanic compounds. Hydrolysis with TMAH mainly depolymerizes lignin to produce phenolic compounds but also converts some polysaccharides in biomass possibly by the peeling reaction and/or alkaline hydrolysis. A sequential combination of OA and TMAH can significantly increase the conversion of the biomass compared to single-or two-step reactions with either the acid or the base. The analysis of liquid products by chemical derivatization followed by gas chromatography equipped with a flame ionization detector (GC-FID) and the characterization of the solid residues by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and 13 C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) reveal strong synergetic effects from the sequential combination of acid and base. In single-step reactions, OA serves as a proton donor to cleave the glycosidic bond between polysaccharide monomers, while TMAH reacts more selectively to lignin than polysaccharides. In two-step tests, the reaction with OA in the first step significantly enhances the conversion with TMAH in the second step by almost twice compared to the corresponding reaction with base alone. GC-FID analysis of the liquid sample shows relatively higher conversion of carbohydrates in the biomass with base in the second step. Py-GC-MS and 13 C CPMAS NMR analysis also reveals that acid treatment in the first step enables base to convert more cellulose in the second step.

Atmospheric pressure pyrolysis of Illinois No. 6 bituminous coal and an approximately 5050 w/w mixture of Texas lignite/Illinois No. 6 coal has been performed at 425-875 OC in a fluidized bed in the presence and absence of different calcined dolomitic stones. Product yields, elemental compositions of char and tar, molecular composition of the gas, fractional distributions of original coal heating value and sulfur in the products, and extents of vapor phase desulfurization and decarbonation by the dolomitic stones were determined. Effects of the dolomite included essentially total removal of H,S and all other vapor phase sulfur, significant CO, reduction at lower temperatures, increased gas yields, and decreased tar yields with some oxygen removal and modest increases in H/C ratio in the latter. The dolomitic stones also gave increased production of H, , CH, and C2+'s while reducing the yields of co.The analysis of crystal size distribution (CSD) in batch operated crystalliiers is considered for various types of operation (cooling, evaporation, and dilution) using moment transformation of the population balance. Semiempirical power law nucleation kinetics independent of magma properties and size-independent or linear sizedependent power law growth kinetic models are assumed. For different modes of operation solution of the population balance coupled with mass balance and moment equations enables the CSD to be defined as a function of time and size. The analytical procedure is illustrated by numerical examples.

Iron-modified carbon-supported platinum electrocatalysts were synthesized by the Bönnemann colloidal method. Physical characterization by the methods of Brunauer-Emmett-Teller, transmission electron microscopy, and X-ray diffraction measurements were conducted to explore the catalyst surface area and particle size, particle distribution, degree of metal alloy, and phase structure. Electrochemical measurements were carried out to characterize the catalyst oxygen reduction reaction ͑ORR͒ activity under the condition of with and without methanol present. The catalyst performance was evaluated by rotating disk electrode sweep voltammetry and cyclic voltammetry techniques. The PtFe catalysts showed enhanced methanol tolerance and catalytic activity compared to Pt catalyst. The PtFe catalysts with atomic compositions of Pt/Fe = 9:1 and Pt/Fe = 1:1 showed more enhanced methanol tolerance and catalytic activity than the Pt/Fe = 3:1.Fuel cell technology has received much attention in recent decades because of growing energy and security concerns. Direct methanol fuel cells ͑DMFCs͒, which were traditionally targeted for small-scale applications, have received significant attention for stationary and automobile applications due to easier fuel feeding system handling, higher fuel energy density, and simpler fueling system compared to hydrogen fuel cells ͑proton exchange membrane fuel cells, PEMFCs͒. 1-3 Besides the high capital and operating cost of fuel cells, there are two major technical barriers for the viable commercialization of PEMFCs/direct methanol fuel cells ͑DMFCs͒. The first barrier relates to water retention capability and proton conductivity of the membrane. 4,5 The second relates to the performance of the electrocatalysts in the electrode reactions. For the electrochemical reaction of DMFCs, theoretically the thermodynamic potential of ϳ1.20 V is almost the same as that of hydrogen oxidation, ϳ1.23 V. However, in practice, there is always a high overpotential of larger than 250 mV, even with platinum as the electrocatalyst on each electrode. The half-cell cathodic reaction of DMFCs, because of the highly irreversible oxygen reduction reaction ͑ORR͒, causes high overpotential, above 250 mV, even under open-circuit potential condition. Combined with the problems of fuel crossover and masstransport loss, the actual cathodic potential is much less than expected.Development and improvements in non-noble cathodic electrocatalysts, catalyst synthesis methods, Pt-based multimetal alloy electrocatalysts, and various catalyst supports are among the many approaches that have been taken to enhance the commercialization of DMFCs. The high cost and limited availability of Pt has increased research on non-noble cathodic electrocatalysts. Transition metal complexes with porphyrin and nonporphyrin ligands have been extensively studied. Some metal phthalocynines and metal oxides have shown some degree of ORR activity; however, their stability and lifetimes still need to be improved. 6,7 Synthesis methods and catalyst supports p...

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