Efficient Jacobian evaluation method in multimode hierarchicalcircuit simulation

An efficient method for Jacobian evaluations in multimode hierarchical circuit simulation is presented. The method evaluates the Jacobian matrix based on the block Jacobian contributions which can be evaluated by various methods for different types of blocks to achieve both accuracy and efficiency. Comparison of the method with the forward-difference method shows considerable improvement in simulation efficiency and convergence     

Comparative control of the bioactivity of some frequently consumed vegetables subjected to different processing conditions

The main aim of this investigation was to find processing conditions and to control them, which maximally preserve bioactive compounds and antioxidant activity of garlic and onions. Garlic, white and red onions were subjected to bleaching and boiling. The contents of polyphenols, flavonoids, flavanols, tannins, corresponding antioxidant activities and their correlation coefficients were determined in various methanol and acetone extracts. The antioxidant activity was determined by 2, 2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), Ferric-reducing/antioxidant power (FRAP) and Cupric reducing antioxidant capacity (CUPRAC) antioxidant assays. It was found that bleaching for 90″ most fully preserves polyphenols (8.25, 9.75 and 11.98 vs. 9.00, 10.52 and 15.87 mg GAE/g DW and the level of antioxidant activity – 8.82, 22.50 and 23.90 vs. 9.00, 23.05 and 24.30 μM TE/g DW of DPPH in extracts of treated samples with 100% of methanol vs. raw garlic, white and red onions, respectively. In conclusion, comparative control shows that bleaching for 90″ of all studied vegetables most fully preserves contents of bioactive compounds and the level of antioxidant activity. Extraction of bioactive compounds with 100% methanol was more effective than with 50% methanol and 100% acetone.     

Development of adhesive bonds with reduced fracture strength as NDE benchmarks

A method for producing adhesively bonded aluminum joints with a predictable loss of fracture strength was developed and evaluated. The method uses an open-faced specimen geometry and a humid high-temperature environment to promote adhesive degradation. The rate of degradation was greatly increased over previous accelerated degradation schemes through the use of MgSO₄ as a contaminant. The contaminant was applied as an aerosol in a purpose-built duct having a controlled airflow. Specimens were prepared and subjected to accelerated aging under a variety of conditions and then fractured using a DCB loading jig. It was found that the contaminant surface concentration was a strong determinant of the fracture strength after hot-wet aging. Exposure to the hot-wet environment was shown to have little effect beyond an initial threshold. Standard ultrasonic imaging techniques were incapable of differentiating between fresh and hot-wet aged specimens, in spite of significant differences in the fracture strength. This is consistent with the hypothesis that the approach produced specimens that simulated the effects of environmental attack, since standard ultrasonic methods, such as those used in the present study, cannot detect such losses of fracture strength in the absence of any delamination between adhesive and adherend. FESEM and EDX analysis of the fracture surfaces showed residual aluminum, suggesting an intra-oxide locus of failure consistent with other accelerated degradation methods. The technique can be used to generate adhesive joint specimens to aid the development of ultrasonic methods capable of detecting the loss of fracture strength associated with environmental degradation.     

Representation of geometric variations using matrix transforms for statistical tolerance analysis in assemblies

The goal of this article is to develop a tolerance representation for assemblies compatible with tolerance analysis based on a closed-form algorithm used in robotic applications. A methodology is described that represents standard Y14.5M-1982 tolerances using homogeneous 4×4 matrix transforms. Transforms represent both the nominal relations between parts and the variations caused by geometric deviations allowed by the tolerances. The analysis calculates a statistical estimate of the location of theNth part in an assembly starting from the first part or a fixture. Except forform tolerances, most types of tolerance specifications are compatible with the proposed representation. This approach is well suited to integration with CAD systems and feature-based design. Since assembly apparatus errors can be calculated using the same methodology, one can predict the relative position and angle errors between two parts about to be mated. This permits useful evaluation of assembly equipment errors, comparison of different product tolerance assignments, and calculations of assembly process capability.     

The atherosclerotic heart disease and protecting properties of garlic: contemporary data

This article reviews the contemporary data concerning atherosclerosis and protecting properties of garlic. Recent advances in basic science have established a fundamental role for inflammation in mediating all stages of this disease from initiation through progression and, ultimately, the thrombotic complications of atherosclerosis. These new findings provide important links between risk factors and the mechanisms of atherogenesis and garlic properties. Numerous in vitro studies have confirmed the ability of garlic to reduce the parameters of the risk of atherosclerosis: total cholesterol, LDL, triglycerides, oxidized LDL. Bioactive compounds and antioxidant potentials in fresh, cooked, boiled and commercial garlic from different regions are presented, using beta-carotene, 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) with K2S2O8 or MnO2, ferric-reducing/antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC) and others assays for antioxidant status. In vivo studies were reviewed on with garlic and cholesterol supplemented diets. The positive influences of garlic on plasma lipids, proteins, antioxidant activity, and some indices of blood coagulation are dose dependent. Garlic could be a valuable component of atherosclerosis-preventing diets only in optimal doses. Many recently published reports show that garlic possesses plasma lipid-lowering and plasma anticoagulant and antioxidant properties and improves impaired endothelial function.