scholarly journals Identification and quantification of fatty acids in hunting web of adult Steatoda grossa (Theridiidae) female spiders

2021 ◽  
Author(s):  
Dżastin Zimny ◽  
Michał Patrzałek ◽  
Teresa Kowalska ◽  
Mieczysław Sajewicz ◽  
Kinga Surmiak-Stalmach ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Tensile Strength ◽  
Spider Silks ◽  
The Web ◽  
Identification And Quantification

AbstractThis is the first study on composition of fatty acids in hunting web of Steatoda grossa (Theridiidae) spiders and one of only four similar studies ever made. Its main contribution is a discovery that fatty acids not only cover an outside of the web fibers, but they are even more abundantly represented in the fibers’ inner structure. Although little attention has been so far attributed to the contents of fatty acids in spider silks, one has to remember that their biocompatibility combined with an extraordinary tensile strength make them a worth investigating template for material bioengineering studies.

Pitting Corrosion and Its Influence on Local Strength of Hull Structural Members

2005 ◽  
Author(s):  
Tatsuro Nakai ◽  
Hisao Matsushita ◽  
Norio Yamamoto
Keyword(s):  
Tensile Strength ◽  
Pitting Corrosion ◽  
Structural Models ◽  
Distortional Buckling ◽  
Thickness Loss ◽  
Bulk Carriers ◽  
The Face ◽  
Face Plate ◽  
Corrosion Pits ◽  
The Web

The objective of this study is to obtain basic data for discussing the structural integrity of aged ships, especially hold frames of aged bulk carriers. Firstly, shapes of corrosion pits observed on hold frames of bulk carriers have been investigated. It was shown that the shape of the corrosion pits is a circular cone and the ratio of the diameter to the depth is in the range between 8 to 1 and 10 to 1. Secondly, a series of tensile tests has been conducted to investigate the effect of pitting corrosion on tensile strength. It was pointed out that the tensile strength decreases gradually and the total elongation decreases drastically with the increase of thickness loss due to pitting corrosion. Thirdly, a series of 4-point bend tests with structural models which consist of shell, web and face plates simulating hold frames of bulk carriers has been carried out to investigate the effect of pitting corrosion on collapse behavior and lateral-distortional buckling behavior. Following the experiment, a series of non-linear FE-analyses has been also made. In the case where tensile load acted on the face plate, cracks were initiated at the bottom of the pits when pitting concentrated on the web near the face plate. On the other hand in the case where compression load acted on the face plate, lateral-distortional buckling has been observed and the ultimate load of the structural models where pitting developed regularly on the web was found to be almost the same as that of the structural models where the web has uniform corrosion corresponding to the average thickness loss.

Alternating Behavior of Fatty Acids in Rubber Compounds

1930 ◽  
Vol 3 (4) ◽  
pp. 612-614
Author(s):  
T. L. Garner
Keyword(s):  
Fatty Acids ◽  
Tensile Strength ◽  
Crystalline Structure ◽  
Melting Points ◽  
Gradual Reduction ◽  
Rubber Compounds ◽  
The Difference

Abstract It has been shown (Bayer, Ber., 10, 1286 (1877); Garner and Randall, J. Chem. Soc., 125, 881 (1924)) that the alternations in the melting points and heats of crystallization of normal fatty acids were due to differences in the crystalline structure. Two distinct curves of behavior corresponding to the acids with odd and even numbers of carbon atoms have been shown for the heats of crystallization. McKee (Naturwissenschaften, 11, 938 (1923)) discussing the fats used in the diet of diabetics, states that in the case of glycerides of acids with an uneven number of carbon atoms these are tolerated and their use leads to gradual reduction in acidosis. Glycerides having an even number of carbon atoms break down during metabolism to form butyric, oxybutyric, and acetoacetic acids. Smith and Boone (Ind. Eng. Chem., 19, 398 (1927)) have experimented with the addition of purified fatty acids to standard mixings of different kinds of raw rubber. They employed molar proportions of the acid to conform with the recommendations of Kratz, Flower, and Coolidge (Ind. Eng. Chem., 12, 317 (1920)) that comparisons of organic accelerators should be made with molecularly equivalent amounts of the substances in question. They determined the tensile strength and elongation of the vulcanized products and found no relations between the elongation and the number of carbon atoms present in the acids, but in the case of the tensile strength an alternating effect was evident, the extent of the differences being affected by cure. The tests were carried out on two kinds of rubber, namely, blanket crepe and pale crepe, and the alternating effect of the acids on the tensile strength was more marked in the former case. As pointed out in the paper, the difference in behavior of the two kinds of rubber when treated with fatty acids was presumably due to the difference in the kind and proportions of acids which they originally contained. In fact, in the case of pale crepe the fatty acids already present in the raw rubber masked the alternating behavior to a marked extent, and the curve obtained was in most respects quite different from that obtained with blanket crepe.

Fatty acids reduce the tensile strength of fungal hyphae during cephalosporin C production in Acremonium chrysogenum

2006 ◽  
Vol 29 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Jong Chae Kim ◽  
Yoon Seok Song ◽  
Dong Hwan Lee ◽  
Seong Woo Kang ◽  
Seung Wook Kim
Keyword(s):  
Fatty Acids ◽  
Tensile Strength ◽  
Cephalosporin C ◽  
Acremonium Chrysogenum ◽  
Fungal Hyphae ◽  
Cephalosporin C Production

Influence of Heat-Stretching Treatment on Structure and Properties of Bico MB Nonwoven Webs

2004 ◽  
Vol os-13 (1) ◽  
pp. 1558925004os-13
Author(s):  
Dong Zhang ◽  
Christine (Qin) Sun ◽  
Yanbo Liu
Keyword(s):  
Tensile Strength ◽  
Air Permeability ◽  
Bending Stiffness ◽  
Structure And Properties ◽  
Machine Direction ◽  
Fiber Splitting ◽  
Web Structure ◽  
Treatment Changes ◽  
The Web

Heat stretching treatment (HST) to side-by-side bicomponent meltblown webs has been carried out on the Stretch Consolidation Pilot Line at the UTK-TANDEC Demonstration Laboratory, to examine the influence of HST on the web structure and properties. The results showed that the fibers aligned preferentially along machine direction after the treatment. Changes in the web structure and properties were studied, including basis weight, thickness, air permeability, tensile strength, bending stiffness, as well as extension recovery (%) from the strain of 50% elongation-to-break, etc. No fiber splitting was observed, which indicated that HST did not result in fiber splitting in the bicomponent meltblown webs as desired.

Resistance of prestressed bridge girders to diagonal tension cracking

2021 ◽  
Author(s):  
Marco A. Roosen ◽  
Max A. N. Hendriks ◽  
Yuguang Yang ◽  
Cor van der Veen ◽  
Dick Schaafsma
Keyword(s):  
Tensile Strength ◽  
Failure Mode ◽  
Bridge Girders ◽  
Shear Reinforcement ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Eurocode 2 ◽  
Prestressed Bridge Girders ◽  
Improved Model ◽  
The Web

<p>Diagonal tension cracking is the governing failure mode for bridge girders with a thin web that are highly prestressed and contain little shear reinforcement. When assessing existing bridge girders using the Eurocode 2 [1], it often turns out that it is not possible to demonstrate sufficient resistance to diagonal tension cracking. This paper evaluates the method to determine the maximum principal tensile stresses as used in the Eurocode 2 [1] and investigates how flexural cracks affect the principle tensile stresses in the regions without flexural cracks. This paper also investigates how the tensile strength of the web is affected by the presence of compressive stresses and by the size of the area subjected to high tensile stresses. Based on the results of these investigations, an improved model is proposed to determine the resistance to diagonal tension cracking.</p>

scholarly journals Comparison of Self-Administered Web-Based and Interviewer Printed Food Frequency Questionnaires for Dietary Assessment in Italian Adolescents

2019 ◽  
Vol 16 (11) ◽  
pp. 1949 ◽  
Author(s):  
Martina Barchitta ◽  
Andrea Maugeri ◽  
Ottavia Agrifoglio ◽  
Giuliana Favara ◽  
Claudia La Mastra ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Correlation Coefficients ◽  
Weighted Kappa ◽  
Rank Test ◽  
Nutrient Intakes ◽  
Web Based ◽  
Food Frequency ◽  
Wilcoxon Rank Test ◽  
Italian Adolescents ◽  
The Web

Innovative tools for assessing food and nutrient intakes in adolescence are essential to uncover the long-term effects of diet on chronic diseases. Here, we developed and compared a web-based self-administered food frequency questionnaire (web-FFQ) with a traditional interviewer printed FFQ (print-FFQ) among 174 Italian adolescents (aged 15–18 years). To assess the reliability of the web-FFQ compared with the print-FFQ, we used Spearman’s rank correlation coefficients, Wilcoxon rank test, quartile misclassification analysis, Cohen’s weighted kappa and the Bland–Altman method. Correlation coefficients ranged from 0.14 (i.e., pizza) to 0.67 (i.e., raw vegetables) for foods, and from 0.45 (i.e., monounsaturated fatty acids, MUFA) to 0.62 (i.e., zinc) for nutrients. Results from the Wilcoxon rank test showed that food and nutrient intakes were comparable between two FFQs, except for nuts, shellfish, fruit juices and MUFA. Adolescents classified into the same or adjacent quartiles ranged from 68.2% (i.e., tea) to 89.1% (i.e., raw vegetables and dipping sauces) for foods, and from 77.2% (i.e., vitamin C) to 87.2% (i.e., folate and calcium) for nutrients. Except for pizza, the weighted kappa indicated moderate to substantial agreement for other foods and nutrients. Finally, we demonstrated that the web-FFQ significantly overestimated shellfish and fruit juice intakes, while it underestimated nuts, canned fish, olive oil, total energy intake, fatty acids and calcium. The limits of agreement analysis indicated moderate to wide individual differences for all groups. In conclusion, our self-administered web-FFQ represents an easy, suitable and cost-effective tool for assessing food and nutrient intakes in adolescents. However, the wide individual differences in level of agreement suggest that additional refinements and calibrations are necessary to investigate the effects of absolute nutrient intakes at the individual level.

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