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Experimental determination and association model for the solubilities of methyl 10-undecenoate with methyl ricinoleate in supercritical carbon dioxide
No full textThe mixture solubilities of methyl 10-undecenoate (M10U) + methyl ricinoleate (MR) in supercritical carbon dioxide (SCCO2) were determined at temperatures from 313 to 333 K, and pressures from 10 to 18 MPa. At constant pressure, the solubilities decreased with an increase with temperature for the investigated range of operating conditions. The maximum solubility enhancement for the current mixture was observed to be 32% for the MR in a mixture of M10U + MR. The maximum selectivity of SCCO2 was 12 towards M10U in a mixture of M10U + MR. The experimental data obtained was internally consistent, as verified by Mendez-Teja model. A new association theory based model was derived and used to model the solubilities of the investigated mixture in SCCO2 along with the literature data
Feedback Capacity and Coding for the BIBO Channel With a No-Repeated-Ones Input Constraint
No full textIn this paper, a general binary-input binary-output channel is investigated in the presence of feedback and input constraints. The feedback capacity and the optimal input distribution of this setting are calculated for the case of an (1, infinity)-RLL input constraint, that is, the input sequence contains no consecutive ones. These results are obtained via explicit solution of an equivalent dynamic programming optimization problem. A simple coding scheme is designed based on the principle of posterior matching, which was introduced by Shayevitz and Feder for memoryless channels. The posterior matching scheme for our input-constrained setting is shown to achieve capacity using two new ideas: history bits, which captures the memory embedded in our setting, and message-interval splitting, which eases the analysis of the scheme. Additionally, in the special case of an S-channel, we give a very simple zero-error coding scheme that is shown to achieve capacity. For the input-constrained binary symmetric channel, we show using our capacity formula that feedback increases capacity when the cross-over probability is small
Stability Analysis of a Large Gold Mine Open-Pit Slope Using Advanced Probabilistic Method
No full textA large gold reserve was recently discovered at Haveri district of Karnataka state of India where open-pit mining was planned to extract these deposits. Stability analysis for open-pit mine slope at this site is presented in the article. Extensive geological investigations and laboratory testing suggested high variability in geological features of discontinuities, rock mass quality and intact rock properties. Hence, it was decided to perform stability analysis of the rock slope using probabilistic approach along with deterministic approach. Deterministic analysis was carried out with average properties of rock, and reliability analysis of the rock slope was carried out using both traditional and advanced probabilistic methods. In traditional probabilistic method, rock mass strength properties were treated as random variables without considering spatial variation of rock properties and reliability index was evaluated by Monte Carlo (MC) simulation on augmented radial basis function-based response surface. In advanced probabilistic analysis, spatial variability of rock mass strength properties was considered by generating anisotropic random field using Fourier series method with spatial averaging over finite difference zones. Reliability index was then estimated by performing MC simulation using random finite difference method. A comparison was provided between the results of stability analysis of slope from all these approaches. Rock slope was found to be stable in both deterministic and probabilistic approaches; however, the degree of stability predicted was different for both methods. Deterministic approach was found to be inappropriate to analyse the stability of slope having rock mass with variable properties. Further, reliability index and expected performance level of slope were highly underestimated by traditional probabilistic method as compared to advanced probabilistic method
Gradient microstructure and texture in wedge-based severe plastic burnishing of copper
No full textIn the present study, gradient microstructure and texture development in wedge-based severe plastic burnishing of oxygen-free high conductivity copper was investigated. Microstructural response and evolution of crystallographic texture in severe surface plastic deformation was shown to be controllable in terms of both magnitude and gradient through control of the incident wedge angle and burnishing parameters. Equiaxed ultra-fined grains and micro/nanoscale elongated grains were produced in the subsurface region, which is indicative of dynamic recrystallization at large strains in the subsurface. Subsurface regions exhibited a significant fraction of shear texture components along the 110 partial fibers. Texture evolution simulated using the visco-plastic self-consistent framework revealed variations in strain level controlling different mechanisms for rotation of these partial fibers from their ideal orientation. Controllability of subsurface properties and microstructure for such materials is briefly discussed. These results allude to fundamental limits in material processing by severe shear using scalable deformation configurations
On the integrated degradation coefficient for adhesive wear: A thermodynamic approach
No full textNormal adhesive wear process in tribological components is characterized by a non-linear behavior during the transient running-in stage followed by a constant rate of steady-state wear. Even though the running-in stage of wear has an imperative significance in defining the component's long-term performance, its characteristics have been largely overlooked in the literature. In general, many of the available predictive models do not consider the contact temperature and the variation in the friction coefficient with time. The present work is an endeavor to propose a complete integrated wear model using the principles of thermodynamics. In this regards, an integrated degradation coefficient is proposed which correlates the time-dependent wear rates (at both running-in and steady-state stage), friction coefficient, and the contact temperature. The efficacy of the proposed degradation coefficient compared to established wear coefficient is demonstrated by considering test results using a vertical pin-on-disk apparatus. Results reveal that the degradation coefficient provides a realistic measure of wear during running period
Some observations considering undrained shear strength, liquidity index, and fluid/solid ratio of mono-mineralic clays with water-ethanol mixtures
No full textThe mechanical properties of clays are influenced by the characteristics of the fluid in the pore space. The liquid limit reacts differently to the permittivity, epsilon, of the fluid: for smectites the slopes are positive, for kaolinite and illite they are negative and smaller. This dissimilarity can be explained by the structural differences between swelling smectites with solvated interlayer cations and nonswelling clay minerals such as kaolinite and illite. Undrained shear strengths, c(u) of Ca-smectite, but not Na-smectite, correlate with the actual fluid ratio. Regressing c(u) against the liquidity index, I-L, yields two different regression lines for Na-smectite and Ca-smectite. For the first time it is shown that normalizing c(u) to the epsilon of the pore fluid results in a single regression line for both smectitic clay types. As kaolinites and illites possess significantly less exchangeable cations than smectites, this yields significantly smaller ranges for Atterberg limits and reduces the impact of e on almost pure particleparticle interactions. In addition, the much larger particle sizes of the kaolinite and illite may dominate the undrained shear strengths, as normalization of c(u )to epsilon did not change the relationship to either the actual water content or the liquidity index
Cu(I)/Ag(I)-3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p `-disulfonate Based Coordination Polymers: Synthesis, Structures and Photoluminescent Properties
No full textThree new coordination polymers (CPs), namely Cu-2(pdtd)(bpy)(2)](n center dot)12H(2)O (1), Ag-2(pdtd)(azpy)](n) (2) and Ag-2(pdtd)](n) (3) (where pdtd=3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p'-disulfonate, bpy=4,4'-bipyridine and azpy=4,4'-azopyridine), have been synthesized and characterized using elemental analysis, IR, UV-vis, thermal studies and finally their structures were determined by single crystal X-ray diffraction technique. The single crystal structural studies reveal that CP 1 is one dimensional structure while, 2 and 3 are two dimensional structures. In case of CP 1 comprising of Cu(I), the sulfonate groups of pdtd ligand are free whereas in 2 and 3 having Ag(I), sulfonate groups of the ligand are bonded to the Ag(I) centres. The photoluminescent properties of all the three CPs have been studied in solid state. All the three CPs display strong emissions in visible region which are red shifted in comparison to the free ligand. The suspension of CP 3 is stable in organic solvents and show emission band similar to that solid state except in nitrobenzene
Wideband stripline fed tapered slot antenna with integral coupler for wide scan angle active phased array
No full textA stripline fed tapered slot antenna (STSA) with integral coupler operating as an active array element over 1.5 octave bandwidth is presented. The proposed STSA with integral coupler features wideband transition which allows a direct 50 stripline feed and enables the coupler to be integrated along with the feed. The coupler helps in taking a sample of signal for online performance monitoring and active phased array calibration. The measured results of antenna element have exhibited good radiation pattern performance with low cross-polarisation in principal plane and low beam squint. Using this, a 16-element H-plane linear phased array antenna designed for the frequency range of 6-18GHz and azimuth scan coverage of 60 degrees is also presented. The active reflection coefficient of the array is calculated from measured mutual coupling coefficients and the array pattern over different scan angles is demonstrated. The grating lobe free scan coverage of 60 degrees is obtained. The antenna array finds application in airborne systems
Unraveling complex nanoscale lipid dynamics in simple model biomembranes: Insights from fluorescence correlation spectroscopy in super-resolution stimulated emission depletion mode
No full textDynamic heterogeneity (DH) at nanoscale due to lipid-lipid and/or lipid-protein interactions in cell membranes plays a crucial role in determining a broad range of important cell functions. In cell membranes, the dimensions of these nanodomains have been postulated to be in the order of 10's of nm and transient in nature. While the structural features of membranes have been studied in detail, little is known about their dynamical characteristics due to paucity of techniques which can probe nanoscale phenomena with simultaneous high temporal resolution. A combination of super-resolution stimulated emission depletion (STED) and fluorescence correlation spectroscopy (FCS) technique can overcome this limitation and provide information about the nanoscale dynamic heterogeneity in cell membranes. Using STED-FCS and FCS diffusion law, we provide an understanding of how nanoscale dynamically organizing lipid platforms can emerge in minimal system of model biomembranes. To illustrate the utility of the technique we have chosen cholesterol containing supported lipid bilayers and demonstrated the role of cholesterol concentration and/or added pore-forming protein, Listeriolysin O (LLO) in determining onset of lipid DH. In addition we have also looked at multi-component lipid bilayers with and without cholesterol to infer about the role of phospholipid and cholesterol composition on lipid dynamics. These results on simple biomimetic systems provide insights into fundamental pathways for the emergence of complex nanodomain substructures with implications for a wide variety of membrane mediated cellular events and depict the significant contribution that STED-FCS can make in resolving several outstanding issues in membrane biology. (C) 2017 Elsevier Inc. All rights reserved
Texture evolution in medium Mn containing TWIP steel: Experiments and Simulation
No full textIn the present work, deformation mechanisms have been studied by evaluating texture and microstructure under cold rolling for medium Mn containing Fe-14Mn-0.5C-3.5Al twinning induced plasticity (TWIP) steel. Rolling has been performed up to true strain similar to 2.3. Microstructural features reveal that deformation takes place by twinning. Texture evolution shows alpha-fiber type texture with a continuous alpha-fiber up to very large strains. Experimentally observed deformation micro-mechanisms have been verified with the visco-plastic self-consistent (VPSC) simulation. Effects of twin volume fraction in texture evolution also been studied by incorporating volume transfer scheme in the VPSC simulation. Simulation results show very good agreement with the experimental results