GENETIC ALGORITHM APPROACH TO A LUMBER CUTTING OPTIMIZATION PROBLEM

Genetic algorithms are a technique for search and optimization based on the Darwinian principle of natural selection. They are iterative search procedures that maintain a population of candidate solutions. The best or most fit solutions in that population are then used as the basis for the next generation of solutions. The next generation is formed using the genetic operators reproduction, crossover, and mutation. Genetic algorithms have been successfully applied to engineering search and optimization problems. This paper presents a discussion of the basic theory of genetic algorithms and presents a genetic algorithm solution of a lumber cutting optimization problem. Dimensional lumber is assigned a grade that represents its physical properties. A grade is assigned to every board segment of a specific length. The board is then cut in various locations in order to maximize its value, A genetic algorithm was used to determine the cutting patterns that would maximize the board value.     

Optical sensing of biomolecules using microring resonators

A biosensor application of vertically coupled glass microring resonators with Q/spl sim/12 000 is introduced. Using balanced photodetection, very high signal to noise ratios, and thus high sensitivity to refractive index changes (limit of detection of 1.8/spl times/10/sup -5/ refractive index units), are achieved. Ellipsometry and X-ray photoelectron spectroscopy results indicate successful modification of biosensor surfaces. Experimental data obtained separately for a bulk change of refractive index of the medium and for avidin-biotin binding on the ring surface are reported. Excellent repeatability and close-to-complete surface regeneration after binding are experimentally demonstrated.     

Topographic variation in biglycan and decorin synthesis by articular cartilage in the early stages of osteoarthritis: an experimental study in sheep

From October 1988 to January 1992, nine isolates of Pseudomonas aeruginosa carrying transferable plasmids encoding imipenem-hydrolyzing beta-lactamase (pI = c. 9.5) were recovered from nine different patients in a neurosurgical ward of a hospital in Japan. The beta-lactamase activities of the sonicated extracts from the transconjugants were inhibited by EDTA and this was partially reversible by the addition of zinc cation. The substrate specificity and pI of the beta-lactamase were similar to those of the metallo beta-lactamases from P. aeruginosa and Serratia marcescens TN9106. All strains were resistant to imipenem, carbenicillin and antipseudomonal cephems including ceftazidime, cefsulodin, cefpirome, while four and five strains were susceptible to piperacillin and aztreonam, respectively. Both low level imipenem resistance and high level cephem resistance were co-transferred with the production of metallo beta-lactamase, while resistance to piperacillin, aztreonam, and high level imipenem-resistance were not selected. Production of chromosomal cephalosporinase in piperacillin resistant strains was derepressed, and production of outer membrane protein of D2 was diminished in highly imipenem resistant strains. Six strains were isolated in 1991, and the amounts of antipseudomonal agents, especially imipenem, used in the neurosurgical ward increased markedly in this year. Only three of the nine isolates had the same serotype, pyocin type and phage type. Our results suggest that the repeated isolation of imipenem and cephem-resistant P. aeruginosa producing metallo beta-lactamase was related to the high usage of antipseudomonal beta-lactam antibiotics such as imipenem, and was exacerbated by the dissemination of a plasmid.     

The effect of electrical stunning and slaughter on the electroencephalogram of sheep and calves

To study the application of electroencephalography (EEG) for the assessment of insensibility during stunning and slaughter, recordings were made on sheep that were slaughtered by throat cutting, electrically stunned head-only and allowed to recover, electrically stunned head-only followed by throat cutting or electrically stunned head-to-back. The same experiments were repeated on calves (1–6 weeks old) except some calves were stunned and allowed to recover before final stunning and throat cutting.

After the throat cut, sheep became insensible (i.e. EEG < 10 μV) at 8–22 s but the calf EEG did not fall below 10 μV until 79 s after the cut. With head-only stunning/recovery, high-amplitude EEG waves (electroplectic fit) continued for 47 s (sheep) and 33 s (calves) post stun. A quiescent period followed, which then developed into a period of moderate-amplitude EEG signals, so that, at 50 s post stun, the EEG usually exceeded 50 μV and often had bursts of 150 μV activity. After head-only stunning/throat cutting, the electroplectic fit was shortened (39 s in sheep, 23 s in calves) and the EEG took at least 50 s to fall below 10 μV. With sheep stunned head-to-back, which stops the heart, and thus should cause immediate, permanent insensibility, the EEG took longer to fall below 10 μV (52 s) than after throat cutting. These results suggest that electrical stunning of sheep and calves causes a prolonged increase in the post-stun EEG amplitude. Therefore, during slaughter, stunned animals have larger amplitude EEG signals than unstunned animals, and EEG criteria developed for judging the sensibility of unstunned animals cannot be used for those that are electrically stunned.     

The effect of multiple yeasts co-inoculations on Sauvignon Blanc wine aroma composition,sensory properties and consumer preference

Consumer acceptance testing has been only recently applied in wine research, to assess wine sensory attributes that affect hedonic liking. The aim of this study was to investigate the effect of Saccharomyces yeast co-inoculations on wine volatile composition and sensory profiles, and to determine if differences were sufficient enough to affect consumer acceptance. Fermentations were conducted using two- and three-yeast co-inoculations, and single strains. Yeast inocula differed substantially in volatile thiols and other flavour compounds, and in their sensory properties. Wines from four yeast inocula which showed large sensory differences were subjected to consumer testing by 120 consumers, with differences in overall liking found. Four clusters of consumers were identified, with one group strongly preferring the two-yeast co-inoculated wine with an intermediate sensory profile, while another group favoured the wine made using the three-yeast co-inoculation. This study has demonstrated that the yeast inoculum used to conduct fermentation affects consumer acceptance.     

Lactation performance and amino acid utilization of cows fed increasing amounts of reduced-fat dried distillers grains with solubles

The use of a solvent-extraction process that removes corn oil from distillers grains produces a reduced-fat co-product (RFDG). To determine the optimal concentration of RFDG in mid-lactation diets, 22 multiparous and 19 primiparous Holstein cows were used in a completely randomized design for 8 wk, including a 2-wk covariate period. The RFDG was included at 0, 10, 20, and 30% of the diet on a dry matter basis, replacing soybean feedstuffs. Increasing RFDG in diets had no effect on dry matter intake (23.1 kg/d) or milk production (35.0 kg/d). Milk fat percentage increased linearly from 3.18 to 3.72% as RFDG increased from 0 to 30% of the diet. Similarly, milk fat yield tended to increase linearly from 1.08 to 1.32 kg/d. Milk protein percentage (2.99, 3.06, 3.13, and 2.99% for diets with RFDG from 0 to 30%) responded quadratically, whereas protein yield was not affected by treatment. Milk urea N decreased linearly from 15.8 to 13.1 mg/dL. The efficiency of N utilization for milk production was not affected by including RFDG (26.1%), whereas the efficiency of milk production (energy-corrected milk divided by dry matter intake) tended to increase linearly with increasing RFDG in the diet. Similarly, concentrations of plasma glucose increased linearly. Arterial Lys decreased linearly from 66.0 to 44.8 μM/L, whereas arterial Met increased linearly from 16.5 to 29.3 μM/L. Arteriovenous difference of Lys decreased linearly from 42.6 to 32.5 μM/L, whereas that of Met was unaffected. The extraction of Lys by the mammary gland increased linearly from 64.3 to 72.2%, whereas that of Met decreased linearly from 71.6 to 42.7%. Feeding up to 30% of RFDG in a mid-lactation diet supported lactation performance similarly to cows fed the soybean protein-based diet (0% RFDG).     

Effective harvesting,detection, and conversion of IR radiation due to quantum dots with built-in charge

We analyze the effect of doping on photoelectron kinetics in quantum dot [QD] structures and find two strong effects of the built-in-dot charge. First, the built-in-dot charge enhances the infrared [IR] transitions in QD structures. This effect significantly increases electron coupling to IR radiation and improves harvesting of the IR power in QD solar cells. Second, the built-in charge creates potential barriers around dots, and these barriers strongly suppress capture processes for photocarriers of the same sign as the built-in-dot charge. The second effect exponentially increases the photoelectron lifetime in unipolar devices, such as IR photodetectors. In bipolar devices, such as solar cells, the solar radiation creates the built-in-dot charge that equates the electron and hole capture rates. By providing additional charge to QDs, the appropriate doping can significantly suppress the capture and recombination processes via QDs. These improvements of IR absorption and photocarrier kinetics radically increase the responsivity of IR photodetectors and photovoltaic efficiency of QD solar cells.