Systems responses to progressive water stress in durum wheat

Durum wheat is susceptible to terminal drought which can greatly decrease grain yield. Breeding to improve crop yield is hampered by inadequate knowledge of how the physiological and metabolic changes caused by drought are related to gene expression. To gain better insight into mechanisms defining resistance to water stress we studied the physiological and transcriptome responses of three durum breeding lines varying for yield stability under drought. Parents of a mapping population (Lahn x Cham1) and a recombinant inbred line (RIL2219) showed lowered flag leaf relative water content, water potential and photosynthesis when subjected to controlled water stress time transient experiments over a six-day period. RIL2219 lost less water and showed constitutively higher stomatal conductance, photosynthesis, transpiration, abscisic acid content and enhanced osmotic adjustment at equivalent leaf water compared to parents, thus defining a physiological strategy for high yield stability under water stress. Parallel analysis of the flag leaf transcriptome under stress uncovered global trends of early changes in regulatory pathways, reconfiguration of primary and secondary metabolism and lowered expression of transcripts in photosynthesis in all three lines. Differences in the number of genes, magnitude and profile of their expression response were also established amongst the lines with a high number belonging to regulatory pathways. In addition, we documented a large number of genes showing constitutive differences in leaf transcript expression between the genotypes at control non-stress conditions. Principal Coordinates Analysis uncovered a high level of structure in the transcriptome response to water stress in each wheat line suggesting genome-wide co-ordination of transcription. Utilising a systems-based approach of analysing the integrated wheat's response to water stress, in terms of biological robustness theory, the findings suggest that each durum line transcriptome responded to water stress in a genome-specific manner which contributes to an overall different strategy of resistance to water stress

Utilisation du Kurtosis dans le diagnostic des défauts combinés d’engrenages par la transformée continue en ondelettes

Ce travail consiste à détecter deux défauts combinés de type choc, simulés sur un engrenage par la transformée continue en ondelettes. L‟idée est de calculer les coefficients avec un pas très fin (0,1) de discrétisation des échelles ce qui permettra d‟avoir une redondance importante, ensuite le Kurtosis est calculé pour tous les vecteurs des échelles, ce qui donne une concentration d‟énergie autour de chaque fréquence de résonance excitée par les défauts. Cette concentration d‟énergie se traduit par des bosses de redondance sur le graphe du Kurtosis. Enfin, l‟analyse des coefficients associés à chaque bosse permet de remonter aux défauts qui les ont excités.Mots-clefs : transformée continue en ondelettes ; défauts combinés ; défauts d’engrenages ; kurtosis ; diagnostic

Vibratory monitoring of gear transmissions in variable regime

This paper falls within the context of diagnosis of rotating machines in speed variable regime. Based on simulation signals, this work has the purpose to find relevant indicators for the diagnosis of gear transmissions in a variable regime. Two indicators are proposed; the first indicator is the RMS value applied to the vibration signal divided by its corresponding instantaneous frequency. The second is the normalised gear frequency by averaging speed. The gear frequency and averaging speed are estimated from the spectrogram. To test the proposed indicators simulate signals have been used. These signals are the results of a dynamic modelling of the gears transmission and are calculated by using the Newmark integration diagram. This dynamic modelling takes into account the eccentricity defect

Structural and Thermal Properties of Polycaprolactone/PEG-Coated Zinc Oxide Nanocomposites

Abstract: In this paper, PCL with PEG-coated ZnO nanocomposites films were prepared by solution casting using dichloromethane as a solvent. ZnO nanoparticles of 24 nm crystallite size were synthesized by chemical precipitation method. Surface modification of ZnO NPs was achieved by solution mixing with low molecular weight PEG and verified by FTIR and TGA. The nanocomposites films were characterized by XRD, FTIR, SEM, and TGA techniques. PEG surface modification of ZnO leads to well-dispersed nanoparticles in the polymer matrix. The incorporation of ZnO NPs in PCL alters the thermal stability of the polymer by up to 110°C degradation onset temperature. Non-isothermal kinetic study was performed by model-fitting Coats-Redfern method. The calculated activation energies of the nanocomposites indicate the catalytic effect of ZnO on the thermal decomposition of PCL.The authors would like to acknowledge the assistance of the ICTP-CSIC technical staff

Structural characterization and thermal degradation of poly(methylmethacrylate)/zinc oxide nanocomposites

This work is based on the preparation of composites of poly(methylmethacrylate) with zinc oxide nanoparticles synthesized by solution casting method. Chloroform cast poly(methylmethacrylate) films containing different amounts of ZnO nanoparticles were characterized by XRD, SEM, UV-vis spectroscopy, FTIR spectroscopy and TGA. The results show that ZnO nanoparticles with a size of 24 nm were fairly dispersed in the polymer matrix. The obtained material had UV shielding capability with optical transparency. Thermal characterization shows that, the nanocomposites were more thermally stable than pure PMMA presenting three degradation steps. Apparent kinetic parameters were determined for each degradation step using peak fitting methodology. According to activation energies, ZnO particles affect simultaneously but oppositely the kinetics of underlying degradation reactions. Thermal stability of the PMMA/ZnO nanocomposites was the result of the overall balance in favor of the inhibiting effect of ZnO.The authors acknowledge the financial support of CNEPRU project N E00720140050. MALM thanks the support from the MINECO project MAT2016-81138-R. The authors appreciate the assistance of ICTP/ SCIC technical staff.Peer Reviewe

Reduction of hydrogen embrittlement of API 5l X65 steel pipe using a green inhibitor

International audienc

Corrosion Inspection and Recommendation on the Internal Wall Degradation Caused Rupture of 6” Gas Line Pipe

International audienceA sudden leak of 6-inch gas line pipe after being in service for 1 year was observed. The pipe was designed to transport dry gas. The failure had taken place in 6 o’clock position at the stage discharge of the flow process. Specimens from the failed part had taken for laboratory investigation in order to find out the cause of the pipe rupture. Visual and metallographic observations confirmed that the pipe split was due to a crack initiated in circumferential and then turned into longitudinal direction. Sever wall thickness reduction was noticed on the internal pipe surface. SEM observations at the fracture surface revealed features of ductile fracture mode. Corrosion product analysis showed the traces of iron carbonate/iron sulphate. Upon the laboratory analysis, the concluded remarks confirmed that the pipe failed due to the effect of wet fluid (condensate) caused severe wall thickness dissolution resulted in pipe could not stand the continuation at in-service working condition