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611.
In this paper, quasi-static fatigue crack growth simulations of homogeneous and bi-material interfacial cracks have been performed using element free Galerkin method (EFGM) under mechanical as well as thermo-elastic load. The thermo-elastic fracture problem is decoupled into thermal and elastic problems. The temperature distribution obtained by solving heat conduction equation is used as input in the elastic problem to get the displacement and stress fields. Discontinuities in the temperature and displacement fields are captured by extrinsic partition of unity enrichment technique. The values of stress intensity factors have been extracted from the EFGM solution by domain based interaction integral approach. The standard Paris fatigue crack growth law has been implemented for the life estimation of various model problems. The results obtained by EFGM under mechanical and thermo-elastic loads were compared with those obtained by FEM using remeshing approach. 相似文献
612.
P. N. Pathak D. R. Prabhu M. Bindu S. C. Tripathi V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):137-142
The primary purpose of this study was to understand the alpha radiolytic degradation behavior of N,N-dihexyl octanamide (DHOA) vis a vis tributyl phosphate (TBP) solutions in n-dodecane under plutonium loading conditions. These studies were carried out as a function of dose on different Pu loaded
samples (containing 0.002-10 g/L Pu) from 4 M HNO3 medium. These Pu loaded solutions were evaluated for stripping behavior by contacting with 0.5 M NH2OH at 0.5 M HNO3 solutions. Organic phase analysis was carried out by gas chromatography (GC) and by visible spectrophotometry. These studies
clearly indicated that Pu stripping becomes difficult with increased dose in the case of TBP system. On the other hand, no
such problem was observed in DHOA system during stripping of plutonium, thereby indicating that DHOA is a promising candidate
for the reprocessing of high burn up Pu rich spent fuels. 相似文献
613.
R. B. Gujar S. A. Ansari A. Bhattacharyya P. K. Mohapatra A. S. Kanekar P. N. Pathak V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):621-627
The radiolytic stability of a branched diglycolamide extractant, namely N,N,N′,N′-tetra-2-ethylhexyl diglycolamide (T2EHDGA) dissolved in n-dodecane containing several phase modifiers, viz. N,N-dihexyloctanamide (DHOA), tri-n-butyl phosphate (TBP), 1-decanol and iso-decanol has been investigated. The distribution ratio of Am(III) decreased with
increased radiation dose studied up to 1000 kGy. Nevertheless, all the composition of extractants showed satisfactory results
up to 500 kGy, beyond which the extractants degraded drastically. The stripping behaviour of Am(III) with 0.2 M HNO3 was found to be unaffected even with the ligand solution irradiated up to 1000 kGy. Extraction of fission product and structural
elements was also investigated using the irradiated solvents and was found to be not significantly affected with increasing
absorbed dose with the exception of Mo which showed sharp rise in the distribution coefficient values. Loading of Nd in the
organic phase decreased with the irradiated solvent due to degradation of the carrier. The effect of the absorbed dose on
physical parameters such as density, viscosity and interfacial tension of the solvents has also been investigated. 相似文献
614.
615.
Selective Photoreceptor Gene Knock‐out Reveals a Regulatory Role for the Growth Behavior of Pseudomonas syringae 下载免费PDF全文
Rashmi Shah Gopal Pathak Thomas Drepper Wolfgang Gärtner 《Photochemistry and photobiology》2016,92(4):571-578
The plant pathogen Pseudomonas syringae (Ps) is a well‐established model organism for bacterial infection of plants. The genome sequences of two pathovars, pv. syringae and pv. tomato, revealed one gene encoding a blue and two genes encoding red/far red light‐sensing photoreceptors. Continuing former molecular characterization of the photoreceptor proteins, we here report selective photoreceptor gene disruption for pv. tomato aiming at identification of potentially regulatory functions of these photoreceptors. Transformation of Ps cells with linear DNA constructs yielded interposon mutations of the corresponding genes. Cell growth studies of the generated photoreceptor knock‐out mutants revealed their role in light‐dependent regulation of cell growth and motility. Disruption of the blue‐light (BL) receptor gene caused a growth deregulation, in line with an observed increased virulence of this mutant (Moriconi et al., Plant J., 2013, 76, 322). Bacterial phytochrome‐1 (BphP1) deletion mutant caused unaltered cell growth, but a stronger swarming capacity. Inactivation of its ortholog, BphP2, however, caused reduced growth and remarkably altered dendritic swarming behavior. Combined knock‐out of both bacteriophytochromes reproduced the swarming pattern observed for the BphP2 mutant alone. A triple knock‐out mutant showed a growth rate between that of the BL (deregulation) and the phytochrome‐2 mutant (growth reduction). 相似文献
616.
Conformational changes of amide cavitands A – C were investigated at varied temperatures and in several solvents. While cavitands A and B , with comparatively smaller substituents such as Et and iPr, were always in vase conformation in non‐polar solvents such as CDCl3, CD2Cl2, (D8)THF, and C6D6, their thermoswitching (vase to kite) was observed in polar solvents such as (D7)DMF and (D6)DMSO or in the presence of acid (TFA) and H‐bonding inhibitor (TFE). Intra‐ and interannular H‐bonds of A and B were clearly observed by low‐temperature 1H‐NMR spectra in CDCl3. No conformational change of cavitand C with bigger substituent (tBu) was observed under any tested temperature range and in polar or non‐polar solvents; C was always in the kite conformation. 相似文献
617.
The vibrational (IR and Raman) and photoelectron spectral properties of hydrated iodine‐dimer radical‐anion clusters, I2.? ? n H2O (n=1–10), are presented. Several initial guess structures are considered for each size of cluster to locate the global minimum‐energy structure by applying a Monte Carlo simulated annealing procedure including spin–orbit interaction. In the Raman spectrum, hydration reduces the intensity of the I? I stretching band but enhances the intensity of the O? H stretching band of water. Raman spectra of more highly hydrated clusters appear to be simpler than the corresponding IR spectra. Vibrational bands due to simultaneous stretching vibrations of O? H bonds in a cyclic water network are observed for I2.? ? n H2O clusters with n≥3. The vertical detachment energy (VDE) profile shows stepwise saturation that indicates closing of the geometrical shell in the hydrated clusters on addition of every four water molecules. The calculated VDE of finite‐size small hydrated clusters is extrapolated to evaluate the bulk VDE value of I2.? in aqueous solution as 7.6 eV at the CCSD(T) level of theory. Structure and spectroscopic properties of these hydrated clusters are compared with those of hydrated clusters of Cl2.? and Br2.?. 相似文献
618.
Dr. Rakesh K. Pathak Prof. Shanta Dhar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3029-3036
Resistance towards chemotherapeutics displayed by cancer cells is a significant stumbling block against fruitful cisplatin‐based therapy. A unique dual‐acting chemotherapeutic modality, Platin‐B, a prodrug of cisplatin and pipobroman‐mimicking alkylating agent, was constructed to circumvent tumor resistance. Platin‐B exhibited a superior cytotoxicity profile in cisplatin‐resistant cancer cells. Enhanced activity and the ability to overcome cancer‐induced resistance of Platin‐B was related to adduct formation with intracellular glutathione, followed by the activity of Platin‐B on the mitochondria of cells, along with its conventional nuclear activity. Alkylating moieties present on Platin‐B enhanced its cellular and subcellular concentration and protected it from early drug sequestration by biological thiols. 相似文献
619.
In this paper we first introduce the concept of compatible mappings of type (B) and compare these mappings with compatible mappings and compatible mappings of type (A) in Saks spaces. In the sequel, we derive some relations between these mappings. Secondly, we prove a coincidence point theorem and common fixed point theorem for compatible mappings of type (B) in Saks spaces. 相似文献
620.
The effect of the presence of two probe waveguides on the dynamics of hyper-Raman processes is studied in terms of quantum Zeno and anti-Zeno effects. Specifically, the enhancement (diminution) of the evolution of the hyper-Raman processes due to interaction with the probe waveguides via evanescent waves is viewed as quantum Zeno (anti-Zeno) effect. This study considers the two probe waveguides interacting with only one of the optical modes at a time. For instance, as a specific scenario, it is considered that the two non-degenerate pump modes interact with each probe waveguide linearly, while Stokes and anti-Stokes modes do not interact with the probes. Similarly, in another scenario, it is assumed both the probe waveguides interact with Stokes (anti-Stokes) mode simultaneously. The present results show that quantum Zeno (anti-Zeno) effect is associated with phase-matching (mismatching). However, it do not find any relation between the presence of the quantum Zeno effect and antibunching in the bosonic modes present in the hyper-Raman processes. 相似文献