Numerical Study of Internal Radius Effect on Mechanical Behavior of P265GH Material

In metallic structures, cracks are mostly initiated at geometric discontinuities of notches or defects. The geometric parameters and discontinuities govern cracks initiation or propagation and therefore affect the resistance of structures during their use. In industry, for economic or security reasons it is seek to know the degree of defects harmfulness and residual life time of structures; This requires the development of models based on fracture mechanics.The objective of this paper is to establish a numerical finite element modeling for a bent specimen using CASTEM2013 computer code. The studied material is P265GH steel commonly used in sheet form in boilers and pressure vessels.The results show that the propagation velocity of crack and stress concentration coefficient increases by increasing the length of the crack and the diameter of the structure

Residual life prediction of defected Polypropylene Random copolymer pipes (PPR)

The polypropylene random copolymer (PPR) is a thermoplastic material generally used for the transport of water under pressure, especially hot water. PPR pipes are exposed to severe conditions in terms of pressure and temperature, hence the need to characterize their fracture behavior in order to avoid the design risks. Sudden overpressure is one of the most common problems in piping. It can affect the security of goods and the safety of people. In this context, we have performed tests of overpressures at the laboratory scale according to ASTM D1599 standard, on virgin and notched pipes, to characterize mechanically the fracture behavior of PPR pipes. Afterwards, we identify experimentally the evolution of their damage. The calculation of the damage, by experimental damage models, have led to determine the three stages of evolution of the damage, which are the initiation, the progression and the acceleration of it. Therefore, the concept of reliability is used to specify the critical life fraction relative to the notch depth (βc) of a defect modeled as an external longitudinal groove on the PPR pipe. A comparison of PPR and HDPE pipes damage and reliability has been done. Moreover, a theoretical reassessment of the damage level was done through a judicious adaptation of the theoretical model proposed by the unified theory. From the latter, we proved that theoretical and experimental results show good agreement and correlations

PERFORMANCE COMPARISON OF NEW DESIGNS OF CHIEN SEARCH AND SYNDROME BLOCKS FOR BCH AND REED SOLOMON CODES

Error correcting codes constitute one of the core technologies in telecommunications field, especially digital communication applications. The objective of this paper is to compare performance among new designs of chien search block on the one hand and syndrome architectures on the other hand in error correcting codes. All comparison of all designs is made by computing the number of logic, bit error rate values and number of iteration in the case of syndrome architectures Analysis results show that the performances of the new designs based on both second factorization method and Three-Parallel Syndrome architecture are superior to the performances of traditional designs

Development and evaluation of diverse promising rapeseed (

Genetic variability is a prerequisite for any plant breeding program, and mutagenesis is a proven way of creating new variation within a crop germplasm. Novel genetic variability in rapeseed was induced by gamma rays, Ethyl Methane Sulphonate (EMS) and combined mutagen treatment, using various doses and concentrations. The objective was to evaluate and compare the obtained M2 mutants for important quantitative traits in two contrasted environments. Data on phenological, morphological and agronomic parameters were recorded. A large variability was observed and mutagenic treatments had a significant effect on all traits studied. Compared to control plants, mutant genotypes derived from seeds treated with low EMS concentrations during moderate time were earlier and characterized by a higher number of pods per plant. For high concentration of EMS during long time and for combinations of physical and chemical mutagens, a significant decrease in plant height and stature was noticed, as compared to control. Besides, plants derived from gamma rays-treated seeds exhibited the highest 1000-seed weight. The novel induced variability may be integrated in rapeseed breeding program as a new germplasm with improved agronomic traits. Particularly, EMS1-7-stable mutant may be exploited to develop efficiently and quickly a new rapeseed cultivar with some desirable traits. The present study highlights once more the possibility to bring novel genetic diversity for rapeseed desirable traits improvement through mutation breeding

Development and Validation of an optimized syndromes block for reed solomon decoder

Reed Solomon decoder plays an indispensable role in many applications involving data transmission, storage applications and Video broadcasting DVB-T and DVB-S2. In this work we propose a new optimized parallel syndrome block [67] for the Reed Solomon RS code (15,11) used in digital Video broadcasting DVB-T. Therefore, this proposed parallel block is compared to the serial syndrome block existing. On the basis of this technique a new architecture based on three syndromes in parallel is developed. This technique reduces both the energy consumption and the number of iterations. The RS code (15, 11) is composed of 255 symbols that are multiples of 3. The symbols are entered in parallel in the syndrome block. These decoding algorithms developed in this work are compared with the existing algorithms, and they are evaluated through a simulation using the hardware description language VHDL, then they are implemented on a Xilinx Spartan type FPGA card using the XILINX software