Aerobic stability of distillers wet grains as influenced by temperature

BACKGROUND: The storability of distillers wet grains (DWG) influences the economic, energetic, and carbon balances of fuel ethanol production, yet there are limited published data on the deterioration of DWG following its production. We used biogenic CO₂ production to assess the aerobic stability of DWG incubated at three temperatures (12 °C, 22 °C, 32 °C) and compared CO₂ production over time to the appearance of mold and changes in DWG color parameters. RESULTS: CO₂ production and mold colonization indicate that at temperatures near 12 °C, the aerobic stability of DWG was high and that it can be stored for at least a 10‐day period. At temperatures close to 22 °C, the onset of increased microbial activity and visible mold colonization occurred between 4 and 7 days and both activity and mold ratings were very high by the ninth day in all three experiments. At 32 °C, 2 days may be a more appropriate limit for storage. CONCLUSION: Temperature and time interact in a nonlinear fashion that permits the prediction of DWG stability boundaries. The simple visual appearance of mold appears to be a reasonable indicator that correlates well (r = 0.694) with CO₂ production, a measure of the aerobic stability of DWG. Published 2012 by John Wiley & Sons, Ltd.     

Divergent consequences of success and failure in Japan and North America: An investigation of self-improving motivations and malleable selves.

Self-enhancing and self-improving motivations were investigated across cultures. Replicating past research, North Americans who failed on a task persisted less on a follow-up task than those who succeeded. In contrast, Japanese who failed persisted more than those who succeeded. The Japanese pattern is evidence for a self-improving orientation: Failures highlight where corrective efforts are needed. Japanese who failed also enhanced the importance and the diagnosticity of the task compared with those who succeeded, whereas North Americans did the opposite. Study 2 revealed that self-improving motivations are specific to the tasks on which one receives feedback. Study 3 unpackaged the cultural differences by demonstrating that they are due, at least in part, to divergent lay theories regarding the utility of effort. Study 4 addressed the problem of comparing cultures on subjective Likert scales and replicated the findings with a different measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of Individual Fiber Failure in Fiber Bundles

The onset of fiber failure signals the commencement of catastrophic structural failure in fiber bundle systems, a process that is important in standalone bundles and in other material structures. In this work, we have demonstrated a technique by which the onset of fiber failure can accurately be identified by monitoring the electrical continuity and resistance of filaments and bundles during loading. The dual sensor/loading functionality of the fibers differs from most prior approaches wherein separate sensors were added to the load-bearing fiber array. Individual fiber failure and bundle onset failures in 50 fiber bundles were reliably and reproducibly detected.     

Spontaneous Covalent Self‐Assembly of the Azoarcus Ribozyme from Five Fragments

Spontaneous covalent assembly of short RNA fragments has been proposed as a plausible prebiotically relevant pathway to a self‐reproducing system. We previously showed that the Azoarcus group I intron could self‐assemble from four RNA fragments. Here, we extended this fragmentation to five RNAs that averaged <40 nucleotides in length. We optimized this reaction and showed that a dehydration–rehydration sequence was the most effective means to date to shift the self‐assembly equilibrium from reactants to products.     

Optical properties of AlGaAs/GaAs nipi superlattices and theirapplication in asymmetric cavity spatial light modulators

Homo-nipi and hetero-nipi superlattices incorporated into asymmetric Fabry-Perot cavity structures are compared and evaluated for possible use as bit plane optical memory elements in terms of the magnitude of their optical nonlinearities, on-off contrast ratio, insertion loss, carrier lifetimes, and power required to change the state of the structure. Changes in superlattice absorption coefficient as high as 1500 cm^-1 and 1300 cm^-1 have been achieved in type I and type II AlGaAs/GaAs hetero-nipi structures, respectively. When normalized to the GaAs quantum well layer thicknesses, the change in absorption coefficient in the type I superlattice was as high as 12000 cm^-1. In asymmetric cavity modulator structures, on-off reflection contrast ratios as high as 60:1, carrier lifetimes as long as 4 ms, and on-state reflectivities as high as 0.62 have been observed. A 54:1 contrast ratio and an insertion loss of 8.5 dB were achieved simultaneously in a planar Fabry-Perot cavity structure excited with a pump beam power of 3.8 mW. The effective carrier lifetime in this case was 25 μs     

Low-Temperature Crack Closure in Fluoride Glass

Radial cracks generated in heavy-metal fluoride glass (HMFG) by Vickers indentation were found to decrease in length as a function of time when exposed to humid environments in the temperature range of 22° to 80°C. Inspection by optical and electron microscopy indicated that the cracks appear to be closing, leaving little or no evidence of the original crack aperture. The effect was observed to increase with time, temperature, and humidity levels for all conditions studied. Possible explanations for this behavior include viscous relaxation of glass in the region of the crack tip, or the generation and transport of a fluoride gel phase to the crack aperture.     

A lossless active clamping circuit for current doubler topologies

This letter presents a new lossless clamping circuit on the secondary side for DC-DC converters with a current-doubler structure. This circuit reduces ringing on secondary-side rectifiers due to leakage inductance. The ringing loss is recovered to the load. As a result, efficiency is improved, and the voltage stress on secondary-side rectifiers is reduced significantly. These improvements allow DC-DC topologies with a current doubler to operate efficiently at high switching frequencies. The operating principle of the clamping circuit is detailed. Simulations and experimental results validate the proposed technique.     

Vibrational feedback control of time delay systems

This paper applies vibrational feedback control to time lag systems. Averaging theory for differential delay systems is presented and then applied to aid in the design of periodic controllers. Both stabilization and transient issues are discussed. An illustrative example is given which demonstrates that the proposed controller: 1) provides superior robustness properties in comparison to time-invariant controllers when applied correctly; 2) is not robust with respect to unmodeled delays; and 3) does not have zero placement capabilities, in the sense defined in the paper