Impact of volatile compounds generated by essential oils on Aspergillus section Flavi growth parameters and aflatoxin accumulation

BACKGROUND: The advantage of essential oils is their bioactivity in the vapour phase, a characteristic that makes them attractive as possible fumigants for stored grain protection. In this study the antifungal and antiaflatoxigenic effects of the volatile fractions of five essential oils (EOs) were evaluated by vapour contact on Aspergillus section Flavi isolates. RESULTS: In maize meal extract agar the volatile fractions of Pimpinella anisum L. (anise), Pëumus boldus Mol. (boldus), Hedeoma multiflora Benth. (mountain thyme), Lippia turbinata var. integrifolia (Griseb.) (poleo) and Syzygium aromaticum L. (clove) were able to decrease the growth rate and lag phase of aflatoxigenic isolates. Boldus EO showed the best antifungal effect on Aspergillus section Flavi growth rate. In sterilised maize grains, boldus and poleo EOs showed antifungal effects on growth rate and aflatoxin accumulation. The volatile fraction of boldus EO completely inhibited the growth of isolates at water activity (a_w) levels of 0.955, 0.930 and 0.900, while poleo EO showed this effect only at the lower a_w levels (0.930 and 0.900). All aflatoxigenic isolates showed reduced total aflatoxin accumulation in the presence of boldus EO under all a_w conditions. CONCLUSION: These findings clearly indicate that the volatile fraction of boldus EO could be used to control aflatoxigenic fungi in stored maize. Copyright © 2009 Society of Chemical Industry     

Effect of uniaxial pressure on ultrasound velocities and elastic moduli in plasma-sprayed ceramics

Microcracks and thin voids in plasma-sprayed ceramics are known to be responsible for elastic anisotropy and for small values of elastic stiffness constants (measured at small stresses), compared with well-sintered materials. The increase of ultrasound velocities with increasing uniaxial pressure up to 300 MPa in three types of plasma-sprayed ceramics was measured in two directions. The corresponding elastic stiffnesses increased from 1.4 to 4.7 times. The experimental results were explained by closing of intrasplat microcracks and intersplat thin voids by uniaxial pressure.     

Investigation of a self-regulating closed throttle microcryogenic system

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 7, pp. 13–14, July, 1989.     

Isothermal decomposition of austenite in high-speed steel

Conclusions Isothermal transformation of austenite at 700–800°C in steels R18 and R6M3 is accompanied by precipitation of M₆C. The alloying and phase cold working of the phase formed (determined from the lattice constant and line broadening), and also the alloying of the phase, decrease with increasing holding time.DeceasedAll-Union Scientific-Research Tool Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No.3, pp. 73–75, March, 1971.     

Cultural algorithms,an alternative heuristic to solve the job shop scheduling problem

In this work, an approach for solving the job shop scheduling problem using a cultural algorithm is proposed. Cultural algorithms are evolutionary computation methods that extract domain knowledge during the evolutionary process. Additional to this extracted knowledge, the proposed approach also uses domain knowledge given a priori (based on specific domain knowledge available for the job shop scheduling problem). The proposed approach is compared with respect to a Greedy Randomized Adaptive Search Procedure (GRASP), a Parallel GRASP, a Genetic Algorithm, a Hybrid Genetic Algorithm, and a deterministic method called shifting bottleneck. The cultural algorithm proposed in this article is able to produce competitive results with respect to the two approaches previously indicated at a significantly lower computational cost than at least one of them and without using any sort of parallel processing.