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During recessions, either declines in actual capital or increases in required capitalmay intensify pressures on banks. One way for banks to boost their capital ratios is byreducing their lending. However, one effect of systematic reductions in the supply ofbank loans during recessions would likely be to accentuate the magnitudes ofmacroeconomic fluctuations. To reduce this source of “procyclicality”, it has beenproposed that Basel II include “escape clauses”. Such clauses might, for example, operateso as to raise required bank capital during macroeconomic expansions and reduce itduring downturns.Apart from formal escape clauses, procyclicality might be reduced or evenreversed in practice if banks exercise sufficient discretion in reporting their charge-offsand loan loss provisions. We propose two hypotheses about the past cyclicality of suchdiscretion. We hypothesize that individual banks tended to report fewer charge-offs andprovisions when the banking system was troubled than when it was generally healthier.That suggested our second hypothesis: Banks tended to cluster more when the bankingindustry was troubled. Banks would maximize the value of their reporting discretion byclustering more then; being similar to other banks raised the likelihood that a bank wouldbe able to exert reporting discretion when it encountered difficulties, because other,similar banks, and thus the banking system as a whole, would likely be troubled at thesame time.We found some support for our hypotheses at large U.S. banks. During the late1980s, when banking was troubled and bank capital ratios were low, individual banksreported fewer charge-offs, ceteris paribus, when the capital ratios of their peers werelower. During the late 1990s, in contrast, when capital ratios were higher, charge-offs atindividual banks were not systematically related to the capital ratios of peer banks. Wealso found that the equity and the asset betas of individual banks tended to cluster morewhen banking was more troubled than they did when banking was less troubled.

During recessions, either declines in actual capital or increases in required capitalmay intensify pressures on banks. One way for banks to boost their capital ratios is byreducing their lending. However, one effect of systematic reductions in the supply ofbank loans during recessions would likely be to accentuate the magnitudes ofmacroeconomic fluctuations. To reduce this source of “procyclicality”, it has beenproposed that Basel II include “escape clauses”. Such clauses might, for example, operateso as to raise required bank capital during macroeconomic expansions and reduce itduring downturns.Apart from formal escape clauses, procyclicality might be reduced or evenreversed in practice if banks exercise sufficient discretion in reporting their charge-offsand loan loss provisions. We propose two hypotheses about the past cyclicality of suchdiscretion. We hypothesize that individual banks tended to report fewer charge-offs andprovisions when the banking system was troubled than when it was generally healthier.That suggested our second hypothesis: Banks tended to cluster more when the bankingindustry was troubled. Banks would maximize the value of their reporting discretion byclustering more then; being similar to other banks raised the likelihood that a bank wouldbe able to exert reporting discretion when it encountered difficulties, because other,similar banks, and thus the banking system as a whole, would likely be troubled at thesame time.We found some support for our hypotheses at large U.S. banks. During the late1980s, when banking was troubled and bank capital ratios were low, individual banksreported fewer charge-offs, ceteris paribus, when the capital ratios of their peers werelower. During the late 1990s, in contrast, when capital ratios were higher, charge-offs atindividual banks were not systematically related to the capital ratios of peer banks. Wealso found that the equity and the asset betas of individual banks tended to cluster morewhen banking was more troubled than they did when banking was less troubled.

This study aimed to investigate the effect of activated carbon (AC) as an immobilization material in acetone-butanol-ethanol fermentation. The AC surface was modified with different physical (orbital shaking and refluxing) and chemical (nitric acid, sodium hydroxide and, (3-aminopropyl)triethoxysilane (APTES)) treatments to enhance the biobutanol production by Clostridium beijerinckii TISTR1461. The effect of surface modification on AC was evaluated using Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, surface area analyses, and X-ray photoelectron spectroscopy, while the fermented broth was examined by high-performance liquid chromatography. The chemical functionalization significantly modified the physicochemical properties of the different treated ACs and further enhanced the butanol production. The AC treated with APTES under refluxing provided the best fermentation results at 10.93 g/L of butanol, 0.23 g/g of yield, and 0.15 g/L/h of productivity, which were 1.8-, 1.5-, and 3.0-fold higher, respectively, than that in the free-cell fermentation. The obtained dried cell biomass also revealed that the treatment improved the AC surface for cell immobilization. This study demonstrated and emphasized the importance of surface properties to cell immobilization.

Environmentally friendly processes for preparing catalysts and converting glucose into 5-hydroxymethylfurfural (HMF) were studied under water-based conditions. A series of aluminum-grafted SBA-15 mesoporous silica with Si/Al molar ratios of 1.5–20 was prepared by tuning aluminum precursors, solvents, and the pH values in grafting. Among them, the 3Al-S15-w-pH 8 catalyst with high acid capacity and mixed acid sites of Lewis and Brønsted acids was fabricated by adjusting the pH value of the water-soluble aluminum precursor to 8 in a water medium. Thus, it converted 87% of glucose at 160 °C for 5 h in the water medium with 33% HMF selectivity. Moreover, the used 3Al-S15-w-pH 8 catalyst was easily regenerated by calcination in air, which was further used for converting glucose to HMF without losing its performance. Our findings provide new ideas for environmentally friendly catalyst preparation and biomass conversion methods, which can be readily applied to catalysis and bio-refining processes.

A simple hydrothermal synthesis of CeO2 was implemented to obtain a series of CeO2-supported gold (Au) catalysts, used for the total oxidation of propene/toluene/CO gas mixtures and the oxidation of CO. CeO2 preparation started from a cerium hydrogen carbonate precursor using a range of different hydrothermal temperatures (HT) from 120 to 180°C. High-resolution transmission electron microscopy, X-ray diffraction, and H2-temperature-programmed reduction data indicated that CeO2 morphology varied with the HT, and was composed of the more active (200) surface. Following Au deposition onto the CeO2 support, this active crystal plane resulted in the most widely dispersed Au nanoparticles on the CeO2 support. The catalytic performance of the CeO2-supported Au catalysts for both oxidation reactions improved as the reducibility increased to generate lattice oxygen vacancies and the number of adsorbed peroxide species on the CeO2 support increased due to addition of Au. The Au catalyst on the CeO2 support prepared at 120°C was the most active in both propene/toluene/CO oxidation and independent CO oxidation.

Thermal pyrolysis of Thai Napier grass, cassava stalk and rice straw were studied thermogravimetrically, which was followed by a kinetic analysis assuming multiple kinetic schemes and a distributed activation energy model (DAEM) with reaction order n = 1 and n ? 1. The results showed that the DAEM described well the experimental data. The assumption of multiple kinetic schemes appeared more reasonable than that of similar studies reported in the literature assuming a single kinetic scheme. Consequently, the kinetic parameters extracted from the present study are more realistic and within reasonable ranges. Overall, the activation energies are within 31.6–223.53 kJ mol-1. The reaction orders are within 1.02–1.32 for the assumption of n ? 1.

Metal-doped graphitic carbon nitride (MCN) materials have shown great promise as effective photocatalysts for the conversion of acetic acid to carbon dioxide under UV–visible irradiation and are superior to pristine carbon nitride (g-C3N4, CN). In this study, the effects of metal dopants on the physicochemical properties of metal-doped CN samples (Fe-, Cu-, Zn-, FeCu-, FeZn-, and CuZn-doped CN) and their catalytic activity in the photooxidation of acetic acid were investigated and discussed for their correlation, especially on their surface and bulk structures. The materials in the order of highest to lowest photocatalytic activity are FeZn_CN, FeCu_CN, Fe_CN, and Cu_CN (rates of CO2 evolution higher than for CN), followed by Zn_CN, CuZn_CN, and CN (rates of CO2 evolution lower than CN). Although Fe doping resulted in the extension of the light absorption range, incorporation of metals did not significantly alter the crystalline phase, morphology, and specific surface area of the CN materials. However, the extension of light absorption into the visible region on Fe doping did not provide a suitable explanation for the increase in photocatalytic efficiency. To further understand this issue, the materials were analyzed using two complementary techniques, reversed double-beam photoacoustic spectroscopy (RDB-PAS) and electron spin resonance spectroscopy (ESR). The FeZn_CN, with the highest electron trap density between 2.95 and 3.00 eV, afforded the highest rate of CO2 evolution from acetic acid photodecomposition. All Fe-incorporated CN materials and Cu-CN reported herein can be categorized as high activity catalysts according to the rates of CO2 evolution obtained, higher than 0.15 μmol/min−1, or >1.5 times higher than that of pristine CN. Results from this research are suggestive of a correlation between the rate of CO2 evolution via photocatalytic oxidation of acetic acid with the threshold number of free unpaired electrons in CN-based materials and high electron trap density (between 2.95 and 3.00 eV).