1,805 research outputs found

    Exploring the cyclic loads conditions on behavior of modified connector plate of steel frame CBF

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    One of the disadvantages of convergent steel frames, is loss of strength of this brace under cyclic loading. Studies in recent years show that in the event of changes in raw form Gusset plate sheet, and the creation of suitable geometry and as well as the type of consumable materials used for it; initial conditions can be provided to increase ductility and resulting increased in energy dissipation. Braces as earthquake resistant elements in different ways are applied to cope with lateral forces of earthquake. One important element of these systems is Gusset plate sheets which plays an important role in the transmission of lateral forces. The behavior of these members can be investigated under tensile and comprehensive loading uniform. The pressure behavior due to its complexity and more failure modes have been less studied. According to investigation conducted, the desired failure mode of Gusset plates under the pressure is surrendered. However, in most cases the connection sheet under pressure surrenders to bucking load and cannot be lodged with the brittle failure and the result does not show good ductility. In order to change the dominant failure mode and delaying bucking of stiffeners Gusset plate the stiffness and changes in their geometry are used. In this study, using Abacus software to evaluate the impact of changes in plate Gusset and the stiffeners edge of sheets have been examined. The results obtained indicate that the postponement of bucking curves in the modified connector plate and thereby improve behavior of connector plates under the pressure forces and also represents the high configurability of modified connector sheets. Keywords: Gusset Plate, Plasticity, Buckling, Brittle Failure

    Solvent-free Oxidation of Alcohols and Mild Catalytic Deprotection of Silyl Ethers with Poly(N,N’-dibromo-N-ethyl-benzene-1,3-disulphonamide) and N,N,N’,N’-tetrabromobenzene-1,3-disulphonamide

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    Poly(N,N’-dibromo-N-ethyl-benzene-1,3-disulphonamide) (PBBS) and N,N,N’,N’-tetrabromobenzene- 1,3-disulphonamide (TBBDA) can be used for solvent-free oxidation of primary and secondary alcohols to the corresponding carbonyl compounds without over-oxidation, and efficient catalytic deprotection of various silyl ethers to hydroxyl groups in aprotic organic solvents under ambient conditions.KEYWORDS: Solvent-free oxidation, alcohols, catalytic deprotection, silyl ethers, PBBS, TBBDA

    Tensile rotary power transmission model development for airborne wind energy systems

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    Rotary airborne wind energy (AWE) systems are a family of AWE devices that utilise networked kites to form rotors. One such device is the Daisy Kite developed by Windswept and Interesting. The Daisy Kite uses a novel tensile rotary power transmission (TRPT) to transfer power generated at the flying rotor down to the ground. Two dynamic models have been developed and compared; one with simple spring-disc representation, and one with multi-spring representation that can take account of more degrees of freedom. Simulation results show that the angular velocity responses of the two TRPT models are more closely correlated in higher wind speeds when the system shows stiffer torsional behaviour. Another interesting point is the observation of two equilibrium states, when the spring-disc TRPT model is coupled with NREL's AeroDyn. Given the computational efficiency of the simpler model and the high correlation of the results between the two models, the simple model can be used for more demanding simulations

    Polymorphism of Pro12Ala in the peroxisome proliferator-activated receptor 2 gene in Iranian diabetic and obese subjects

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    Background: Peroxisome proliferator-activated receptor 2 (PPAR2) is a nuclear receptor that regulates adipocyte differentiation, lipid metabolism, and insulin sensitivity. The aim of this study was to investigate the association between the Pro12Ala single nucleotide polymorphism (SNP) at the PPAR2 gene and type II diabetes (T2DM) and obesity in an Iranian population. Methods: The genomic DNA of the 312 subjects included four groups: (1) nonobese with type II diabetes, (2) obese without type II diabetes, (3) obese with type II diabetes, and (4) nondiabetic nonobese controls. The Pro12Ala polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Results: Frequencies of the Ala allele in obese subjects were significantly different from those control subjects (odds ratio [OR], 2.358; 95% confidence interval [CI], 1.101-5.05) (P = 0.025). In contrast, no significant association was detected between the Pro12Ala polymorphism and type II diabetes (OR, 0.652; 95% CI, 0.261-1.628). In all subjects, the Ala carriers had a higher body mass index (BMI) compared with the common allele. Conclusions: Our results showed that the Pro12Ala polymorphism in the PPAR2 gene is associated with obesity in Iranian subjects and the presence of the Ala allele could predict higher BMI. © 2009 Mary Ann Liebert, Inc

    Variations of the McEliece Cryptosystem

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    Two variations of the McEliece cryptosystem are presented. The first one is based on a relaxation of the column permutation in the classical McEliece scrambling process. This is done in such a way that the Hamming weight of the error, added in the encryption process, can be controlled so that efficient decryption remains possible. The second variation is based on the use of spatially coupled moderate-density parity-check codes as secret codes. These codes are known for their excellent error-correction performance and allow for a relatively low key size in the cryptosystem. For both variants the security with respect to known attacks is discussed
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