Prediction of mode I fracture toughness of unidirectional fibre composites with arbitrary crack fibre orientation from its lowest or matrix fracture tougness

Corrigendum

Prediction of mode I fracture toughness of unidirectional fibre composites with arbitrary crack fibre orientation from its lowest or matrix fracture tougnessby P.K. Sarkar and S.K. Maiti     

Average-case analysis of the Modified Harmonic algorithm

In this paper we analyze the average-case performance of the Modified Harmonic algorithm for on-line bin packing. We first analyze the average-case performance for arbitrary distribution of item sizes over (0,1]. This analysis is based on the following result. Letf ₁ andf ₂ be two linear combinations of random variables {N _i } _i=1 ^k where theN _i 's have a joint multinomial distribution for eachn= _i=1 ^k ,N _i . LetE(f ₁) O andE(f ₂) 0. Then lim_n E(max(_{f 1},f ₂ ))/n = lim _n max(E(f ₁),E(f ₂))/n. We then consider the special case when the item sizes are uniformly distributed over (0,1]. For specific values of the parameters, the Modified Harmonic algorithm turns out to be better than the other two linear-time on-line algorithms—Next Fit and Harmonic—in both the worst case as well as the average case. We also obtain optimal values for the parameters of the algorithm from the average-case standpoint. For these values of the parameters, the average-case performance ratio is less than 1.19. This compares well with the performance ratios 1.333. and 1.2865. of the Next Fit algorithm and the Harmonic algorithm, respectively.     

CO2 laser annealing of plasma-deposited high-Tcsuperconducting thick films

Recent advances in the fabrication of high-T _c superconducting thick films demand processing techniques which can eliminate film/substrate interdifiusion that occurs during subsequent post-annealing heat treatment after the film is deposited, thereby limiting the application of the thick films for devices. The present study evaluates laser annealing techniques for plasma-deposited Y-Ba-Cu-O thick films using a high-energy CO₂ laser (10.6m) in a continuous wave mode. The results are compared with those obtained by conventional furnace annealing techniques necessary for post-heat treatment of as-deposited superconducting thick films. The high-T _c superconducting phase is recovered by cationic diffusion during subsequent post-annealing heat treatment. Crystallographic phases and microstructural characterization have been performed using XRD, SEM, and EPMA analytical techniques. The significance of the technology lies in the elimination of film/substrate interdiffusion problems, thereby resulting in high-quality superconducting thick films. The technology will significantly reduce the post-annealing times usually required by conventional furnace annealing techniques.     

An efficient algorithm for maxdominance, with applications

Given a planar setS ofn points,maxdominance problems consist of computing, for everyp S, some function of the maxima of the subset ofS that is dominated byp. A number of geometric and graph-theoretic problems can be formulated as maxdominance problems, including the problem of computing a minimum independent dominating set in a permutation graph, the related problem of finding the shortest maximal increasing subsequence, the problem of enumerating restricted empty rectangles, and the related problem of computing the largest empty rectangle. We give an algorithm for optimally solving a class of maxdominance problems. A straightforward application of our algorithm yields improved time bounds for the above-mentioned problems. The techniques used in the algorithm are of independent interest, and include a linear-time tree computation that is likely to arise in other contexts.The research of this author was supported by the Office of Naval Research under Grants N00014-84-K-0502 and N00014-86-K-0689, and the National Science Foundation under Grant DCR-8451393, with matching funds from AT&T.This author's research was supported by the National Science Foundation under Grant DCR-8506361.     

An information-theoretic approach to the written transmission of old English

Information theory offers a means for analyzing some constraints on the reading and copying process in Old English. Entropy for strings of various lengths offers a baseline measure of the uncertainty involved in transmission of Old English texts, while avoiding the pitfalls of applying models of modern reading to early medieval practice. Analysis of lengthy prose and verse texts in Old English revealed uniformly high values for entropy at all string lengths. High entropies may be the result of the language's irregular orthography, poetic koiné, and several dialects and imply that the language may have been easy to write but difficult to read. The low redundancy of the language which its high entropy values indicate suggests that the reader of Old English played an enhanced role in decoding a text and may provide an explanation for the high variability in the transmission of Old English verse.Katherine O'Brien O 'Keeffe is Professor of English at Texas A&M University and a co-director of its Interdisciplinary Group for Historical Literary Study.William Rundell is Professor of Mathematics at Texas A&M University.     

Class separation of mutagenic polycyclic organic material in grilled and smoked foods

Zusammenfassung Es wird über ein Verfahren zur Abtrennung der in gegrillten und geräucherten Lebensmitteln enthaltenen mutagenen polycyclischen organischen Stoffe in einzelne Klassen berichtet. Das Verfahren umfaßt eine erste Extraktion mit Aceton, das Abscheiden von Fett und Proteinen durch Ausfällung bei –55 °C und eine Säure-Base-Extraktion. Die weitere Fraktionierung erfolgte durch Gelfiltration und Silicagel-Chromatographie. Bei vier Proben von gegrillten Würsten waren 80 bis 90% der extrahierten Mutagenität (TA98 + S9) in den basischen Fraktionen enthalten. Die in der Flamme gegrillten Würste hatten eine höhere Mutagenität als die auf Holzkohle gegrillten. Bei den geräucherten Fischen war die Mutagenität gering und verteilte sich gleichmäßig auf die basischen und die neutralen/sauren Fraktionen. Einige Proben zeigten schwache Direktmutagenität in den neutralen/sauren Fraktionen. Die Anwesenheit von Nitrit in den gegrillten Würsten hatte keinen erheblichen Einfluß auf die Mutagenität. Die Gaschromatographie, Selektive Ionregistrierung-Technik, wurde erfolgreich zur Identifizierung mehrerer PAH-Verbindungen eingesetzt, und mit ihr konnten mehrere Nitro-PAH und oxydierte Verbindungen vorläufig identifiziert werden. Der Nachweis der Mutagene in den basischen Fraktionen gestaltete sich jedoch wegen Peak-Schweifbildung und mit-eluierenden Materials kompliziert.Summary A method for class separation of mutagenic polycyclic organic material in grilled and smoked foods is described. The procedure involves an initial extraction with acetone, removal of fat and proteins by precipitation at –55 °C, and an acid-base extraction. Further fractionation was carried out by gel filtration and silica gel chromatography. In four samples of grilled sausages, 80%–90% of the extracted mutagenicity (TA98 + S9) was contained in the basic fractions. Flame-grilled sausages showed higher mutagenicity than charcoal-grilled ones. In a smoked fish sample, the mutagenicity was low and evenly distributed between the basic and the neutral/acidic fractions. A few samples showed a weak direct-acting mutagenicity in the neutral/acidic fractions. The presence of nitrite in grilled sausages did not influence the mutagenicity markedly. Gas chromatography-selected ion monitoring was used to successfully identify a number of polycyclic aromatic hydrocarbons (PAHs) and tentatively identify several nitro-PAHs and oxygenated compounds. However, the identification of mutagens in the basic fractions was complicated by peak tailing and the presence of co-eluting material.

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Abtrennung mutagenen polycyclischen organischen Materials in gegrillten und geräucherten Lebensmitteln

     

Changes in free amino acids content in albacore (Thunnus alalunga) muscle during thermal processing

Summary The effects of cooking and sterilization at several temperatures on the free amino acids (FAA) content in albacore (Thunnus alalunga) muscle were studied during the processing of canned tuna. FAAs were derivatized witho-phtalaldehyde, separated on a C18 column by HPLC and detected by both fluorescence and ultra-violet detectors. After cooking the loss of FAAs was not significant. However, in the final product sterilized at 115 °C and 110 °C (throughout the whole process) there were significant losses with regard to the start material, but not at 118 °C (all temperatures leading to the same lethal F-value). The influence of the thermal process time at 115 °C was evaluated for 60 and 100 min. Significant losses were found between both canned products (25%) and between the raw fish and the final product (12% and 34%, process time 60 and 100 min, respectively). The determination of the content of FAA present in canned albacore may be a useful indication of the severity of the thermal processing.

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Veränderung im Gehalt an freien Aminosäuren in Thunfischmuskel (Tunnus alalunga) während der Wärmebehandlung

Zusammenfassung Die Wirkung des Kochens und Sterilisierens bei verschiedenen Temperaturen auf den Gehalt an freien Aminosäuren (FAA) im Thunfischmuskel (Thunnus alalunga) wurde während der Herstellung von Thunfischkonserven untersucht. Die freien Aminosäuren wurden mito-Phtalaldehyd derivatisiert, auf einer C-18-Kolonne mit HPLC abgetrennt und durch Fluorescenz und UV-Detektoren nachgewiesen. Nach dem Kochen war der Verlust an FAA nicht signifikant, jedoch in dem bei 110° und 115 °C sterilisierten Endprodukt ergaben sich signifikante Verluste bezogen auf das Ausgangsmaterial, aber nicht auf das bei 118 °C erhitzte; alle Erhitzungstemperaturen führen zu demselben letalen F-Wert. Der Zeiteinfluß der Erhitzung bei 115 °C wurde bei 60 und 100 min bewertet. Signifikante Verluste sind bei beiden Dosenkonserven aufgetreten (25%) und zwischen diesen und dem Rohfisch ( 12% und 34%) bei einer Erhitzungszeit von 60 und 100 min). Die Bestimmung des FAA-Gehalts in Thunfischkonserven kann für den Nachweis der Einwandfreiheit des thermischen Prozesses sehr nützlich sein.

     

The effect of hydrothermic treatment on the physicochemical properties of rye grain

Summary The gelatinized, autoclaved and sodiumhydroxide-treated starch preparations were used and their interaction with soluble pentosans and gliadin was analysed. The molecular sieving technique and optical methods were used to detect the complexes formed. The modified starches formed complexes with both soluble pentosans and gliadin in acidic and neutral media (non-ionic molecular forces being involved). The autoclaved starch showed the highest reactivity. The amylose and amylopectin played different roles in the interactions and the aggregates of amylose with gliadin and amylopectin with soluble pentosans were the prevailing forms present in the complexes. Small quantities of other products were also identified.

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Einfluß der hydrothermischen Behandlung auf die physiko-chemischen Eigenschaften des RoggenkornsII. Wechselwirkung der Eiweiß-und Kohlenhydratkomplexe (Modelluntersuchung)

Zusammenfassung Die Wechselwirkungen verkleisterter, autoklavierter und mit Natronlauge behandelter Stärke mit löslichen Pentosanen und Gliadin werden mit Hilfe der Gelpermeation und mit optischen Methoden untersucht. Die modifizierten Stärken bildeten Komplexe mit den Pentosanen und mit Gliadin im sauren und neutralen Medium, autoklavierte Stärke zeigte die hächste Reaktion. Die unterschiedliche Rolle von Amylose und Amylopection zeigte vorherrschend Amylose-Gliadin und Amylopectin-PentosanKomplexe, während andere Komplexe in kleineren Mengen auftraten.

     

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