A Prediction Method of the Behavior of Adhesively Bonded Structures under Cyclic Shear Loading Based on a Characterization of the Viscous Aspects of the Adhesive in an Assembly

The capabilities of structural bonding are more and more used. Estimating the abilities of an adhesive to endure repetitive loadings and to keep stable its mechanical properties along service life is an essential point to analyze in order to conduct fatigue assessments. The aim of this study is to develop a predictive tool for describing the fatigue behavior of an adhesive in an assembly under cyclic loadings. The approach developed analyzes the influence of viscosity on the mechanical behavior of an adhesive in an assembly based on monotonic and creep test results. Thanks to the evaluation of viscous phenomena, it is possible to predict the cyclic response of the adhesive. The experimental approach uses a unique bonded joint designed to limit the stress concentrations and with a maximum stress state in the center of the adhesive. In this paper, following the strategy developed under monotonic loading, experimental results under cyclic loading are presented for different types of loading using several load ratios and amplitudes. These results underline that the evolution of viscous deformations depends on the loading type. Under shear loading and for a ductile structural adhesive, the experimental results are well described using a viscoelastic–viscoplastic constitutive model with nonlinear viscous parameters. This model makes it possible to analyze the influence of different parameters on the mechanical response of bonded joints under cyclic shear loadings.     

Bis-(1-chlor-3-phenoxy-prop-2-yl)-sulfane – Nucleophile Substitution und Regiochemie,Diastereomerentrennung und -zuordnung. Synthese diastereomerenreiner Trithiacyclen

Bis-(1-chloro-3-phenoxy-prop-2-yl)-sulfanes – Nucleophilic Displacement and Regiochemistry. Separation and Assignment of Diastereomers. Synthesis of Diastereomerically Pure Trithiacycles The title compounds 1 were substituted by a series of O-, N- and S-nucleophiles (H₂O solvolysis, AgOAc, NaN₃, KSCN, NaSPh, thiourea). A strong tendency to β-elimination of HCl depending on the kind of the attacking nucleophile was found. In most cases no regioisomerization could be detected in the isolated products of the nucleophilic displacement. Best results were obtained with sulfur nucleophiles. The separation of the diastereomeric mixture of the p-kresyl derivative 1b into the individual diastereomers 1bA and 1bB in a preparative scale was achieved. These 3-thia-1,5-dichlorides and several products of substitution could be assigned to the meso- or (±)-form by examination of the stereochemistry and symmetry of the corresponding sulfoxides. The 1,5-dimercapto derivatives 8 are convenient as structural units for the synthesis of diastereomerically pure cis- or trans-disubstituted trithiacycles e.g. 15bA , 15bB . The (±)-form of the 4,6-disubstituted 2,5,8-trithia[9]-(2,6)-pyridinophane 16bA was characterized by X-ray crystal structure determination.     

Hyperphagia modifies FA profiles of plasma phospholipids,plasma FFA,and adipose tissue TAG

Hyperphagia was achieved by continuous intracerebroventricular infusion of a melanocortin receptor antagonist (HS024; Neosystem, Strasbourg, France) in rats. The effects of hyperphagia on FA composition and concentration of plasma phospholipids (PL), plasma FFA, and adipose tissue TAG were studied in rats for 8 d [short-term hyperphagia (STH); n=8], or 28 d [longterm hyperphagia (LTH); n=9]. The control rats were treated with artificial cerebrospinal fluid for 8 d (n=8) or 28 d (n=10). The rats were fed the same regular diet. In STH rats the plasma PL and fasting plasma FFA contained higher concentrations of saturated FA (SFA) and monounsaturated FA (MUFA), and plasma FFA contained lower n−6 PUFA than in the control rats. In LTH rats the plasma PL contained higher concentrations of SFA, MUFA, and n−3 PUFA and higher proportions of 16∶1n−7 and 18∶1n−9 at the expense of 18∶2n−6 than in the control rats. In LTH rats the abundant dietary intake of 18∶2n−6 did not enrich 18∶2n−6 of the plasma PL or adipose tissue TAG. In LTH rats the fasting plasma FFA contained more than twofold higher concentrations of SFA and MUFA, and higher proportions of 16∶1n−7 and 18∶1n−9 at the expense of 18∶2n−6 than in the control rats. This animal obesity model shows that LTH affects the FA composition and concentration of plasma PL, plasma FFA, and adipose tissue TAG, a result consistent with changes associated with increased risk of various diseases in humans. These results also demonstrate that LTH alters the FA composition of plasma PL and adipose tissue TAG in a way that does not reflect the FA composition of dietary fat.     

The Effect of Surface Engineering Treatments on the Fatigue Behavior of 2024-T351 Aluminum Alloy

The work examines the effect of controlled shot peening (CSP), laser shock peening (LSP) and ultrasonic impact treatment (UIT) on the fatigue behavior of 2024-T351 aluminum alloy. The testing methodology has been designed to extract information regarding specific products of the treatments and their individual affect on fatigue damage. The work concludes that all three surface treatments improve the fatigue resistance of the material with the LSP covering the areas of safe-life and damage tolerance, the control shot peening can only benefit the area of short crack growth while the UIT proved to benefit both the short and long crack growth.     

Stärkebestimmung in Kindermehl

European Food Research and Technology -     

Spirituosen und Essig

European Food Research and Technology -     

Heterocyclic syntheses with malonyl chloride. 15. 7-Chloro-3,4-dihydro-4,5-dioxo-3-aryl(or-alkyl)-2-thio-2H,5H-pyrano[3,4-2-e]-1,3-oxazine from aryl or alkyl isothio-cyanates and their degradation with morpholine and ethanol

Substituted aromatic isothiocyanates with malonyl chloride yield 7-chloro-3-substituted-3,4-dihydro-4,5-dioxo-2-thio-2H,5H-pyrano [3,4-e]-1,3-oxazine ( 1 ). Alkyl isothiocyanates with malonyl chloride yield a mixture of 7-chloro-3-alkyl-2-thio pyranooxazine ( 2 ) and the 2-oxo-analogue ( 3 ). The pyrano oxazine 1 react stepwise with morpholine undergoing replacement of the 7-chloro substituent yielding the 7-morpholino analogue ( 4 ), then the pyrone ring was opened producing 5-morpholino carbonyl-4-oxo-3-substituted phenyl-2-thio-1,3-oxazine-6-ylacetomorpholid ( 5 ). Finally the oxazine ring was opened yielding 2-substituted phenyl carbomyl-3-morpholino-N,N-glutaconoyldimorpholine ( 6 ). Ethanol react with compound 1 at any molar ration causing the opening of the pyrone ring and retain the oxazine ring. Mass spectra. ¹H-n.m.r., u.v. and i.r. spectroscopic data provided information about the fine structures of the products.