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131.
In this paper, we address the implications when a homogeneous dust model is considered for a scenario of gravitational collapse in the context of Eddington‐inspired Born‐Infeld (EiBI) theory. In order to describe the dynamical evolution of the collapse, we present an effective equation, which constitutes the first order corrections, in EiBI coupling parameter κ, to Einstein's field equations. The geometry outside the collapsing object is derived by imposing the standard Darmois‐Israel junction conditions at the boundary surface of the dust. This induces an effective matter source in the outer region which gives rise to a non‐singular, non‐Schwarzschild geometry at the final state of the collapse. For this exterior geometry, we find the threshold of mass for the formation of the black hole. This provides a cut‐off over κ as .
132.
Frequency domain Volterra analysis of MIMO nonlinear systems is complicated by the need to keep track not only of the multi-dimensional interactions between frequencies, but also of the inputs at which these frequencies are applied and the outputs at which the response is observed. A new notation has been introduced which helps clarify this analysis, simplifying issues of kernel symmetry and opening a pathway for more general proofs and automated computation. The new notation is then used to prove and develop a new MIMO harmonic probing algorithm which allows simultaneous probing on multiple inputs, in contrast to prior work which requires sequentially setting other inputs to zero in order to isolate the response of each MIMO frequency response function (FRF) in turn. The method is illustrated through the analysis of a coupled nonlinear mass-spring-damper system and provides new insight into the structure of the FRFs in this case. 相似文献
133.
Yaser Ghazi Akbar Vaseghi Sepideh Ahmadi Fatemeh Haddadi 《Journal of fluorescence》2018,28(2):633-638
Gene expression analysis is considered to be extremely important in many different biological researches. DNA-based diagnostic test, which contributes to DNA identification, has higher specificity, cost, and speed than some biochemical and molecular methods. In this study, we try to use the novel nano technology approach with Multiplex RT-PCR and Gold nano particular probes (GNPs-probes) in order to get gene expression in Curcumas melons. We used Agrobacterium tumefactions for gene transfer and GUS reporter gene as a reporter. After cDNA synthesis, Multiplex PCR and Multiplex RT-PCR techniques were used. Finally, probes were designed for RNA of GUS and Actin genes, and then the analysis of the gene expression using the probes attached to GNPs was carried out and the color changes in the GNPs were applied. In the following, probes hybridization was checked with DNA between 400 to 700 nm wavelengths and the highest rate was observed in the 550 to 650 nm. The results show that the simultaneous use of GNP-attached detectors and Multiplex RT-PCRcan reduce time and costmore considerably than somelaboratory methods for gene expiration investigation. Additionally, it can be seen thatthere is an increase in sensitivity and specificity of our investigation. Based on our findings, this can bea novel study doneusingMultiplex RT-PCRand unmodified AuNPs for gene transfer and expression detection to plants. We can claim that this assay has a remarkable advantage including rapid, cost-effectiveness, specificity and accuracy to detect transfer and expression genes in plants. Also,we can use this technique from other gene expressionsin many different biology samples. 相似文献
134.
The present work represents a two-dimensional numerical prediction of forced turbulent flow heat transfer through a grooved tube. Four geometric groove shapes (circular, rectangular, trapezoidal and triangular) were selected to perform the study, as well as two aspect ratios of groove-depth to tube diameter (e/D = 0.1 and 0.2). The study focuses on the influence of the geometrical shapes of grooves and groove-depth on heat transfer and fluid flow characteristics for Reynolds number ranging from 10,000 to 20,000. The characteristics of Nusselt number, friction factor and entropy generation are studied numerically by the aid of the computational fluid dynamics (CFD) commercial code of FLUENT. It is observed that the best performance occurs with the lower depth-groove ratio, whereas it is found that the grooved tube provides a considerable increase in heat transfer at about 64.4 % over the smooth tube and a maximum gain of 1.52 on thermal performance factor is obtained for the triangular groove with (e/D = 0.1). 相似文献
135.
Rasoul Nazari Moghaddam Behzad Rostami Peyman Pourafshary Yaser Fallahzadeh 《Transport in Porous Media》2012,92(2):439-456
Dissolution of CO2 into brine causes the density of the mixture to increase. The density gradient induces natural convection in the liquid phase,
which is a favorable process of practical interest for CO2 storage. Correct estimation of the dissolution rate is important because the time scale for dissolution corresponds to the
time scale over which free phase CO2 has a chance to leak out. However, for this estimation, the challenging simulation on the basis of convection–diffusion equation
must be done. In this study, pseudo-diffusion coefficient is introduced which accounts for the rate of mass transferring by
both convection and diffusion mechanisms. Experimental tests in fluid continuum and porous media were performed to measure
the real rate of dissolution of CO2 into water during the time. The pseudo diffusion coefficient of CO2 into water was evaluated by the theory of pressure decay and this coefficient is used as a key parameter to quantify the
natural convection and its effect on mass transfer of CO2. For each experiment, fraction of ultimate dissolution is calculated from measured pressure data and the results are compared
with predicted values from analytical solution. Measured CO2 mass transfer rate from experiments are in reasonable agreement with values calculated from diffusion equation performed
on the basis of pseudo-diffusion coefficient. It is suggested that solving diffusion equation with pseudo diffusion coefficient
herein could be used as a simple and rapid tool to calculate the rate of mass transfer of CO2 in CCS projects. 相似文献
136.
Gérald Franz Farid Abed-Meraim Jean-Paul Lorrain Tarak Ben Zineb Xavier Lemoine Marcel Berveiller 《International Journal of Plasticity》2009
In order to investigate the impact of microstructures and deformation mechanisms on the ductility of materials, the criterion first proposed by Rice is applied to elastic–plastic tangent moduli derived from a large strain micromechanical model combined with a self-consistent scale-transition technique. This approach takes into account several microstructural aspects for polycrystalline aggregates: initial and induced textures, dislocation densities as well as softening mechanisms such that the behavior during complex loading paths can be accurately described. 相似文献
137.
Ring-oxygenation of metallotexaphyrins, promoted by strong bases, produces oxotexaphlorin, the first example of a meso-oxo functionalized texaphyrin derivative. 相似文献
138.
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140.
Titanium oxide nanoparticles were coated on multiwall carbon nanotubes (MWCNTs) using an atmospheric pressure chemical vapor
deposition (CVD) to achieve highly compact nanoparticles of about 5 nm on CNT structure. The CNTs with a diameter of about
50 nm were grown by plasma enhanced CVD. Gas sensitivity of the fabricated structure was investigated and compared with TiO2/CNT composite-based gas sensors. The effect of the structural interaction between the nanoparticles and the CNT wall on sensing
mechanism of the as-prepared gas sensors was investigated. Ultrasensitive gas sensors were obtained by TiO2/CNT nanostructures with strong interaction between the MWCNT and the TiO2 nanoparticles. The measurements show high chemical activity and exceptional electrical response of the as-prepared structure
being exposed to gases. Scanning and transmission electron microscopy and X-ray diffraction analysis were used to obtain structural
information. 相似文献