Journal of Thermal Analysis and Calorimetry - In the present framework, the combined effect of magnetic field (Hartmann number, Ha), angle of inclination $$(\alpha )$$ , nanoparticle volume... 相似文献
Traditionally, twist drills with a few specific point geometry, such as planar, conical, cylindrical, ellipsoidal or hyperboloidal, have been designed and adapted for specific applications. Using CAD, the point geometry can be given a generic definition which will enhance the freedom to design drills with different point profiles and optimize them for multiple objectives. Such a definition can also be used for several downstream applications. This paper presents a methodology to model the twist drills with generic point geometry using NURBS. To begin with, a detailed basic model for a fluted twist drill with sectional geometry made up of arcs and straight lines has been presented in terms of bi-parametric surface patches. The coordinates of cutting lips and chisel edge of the drill have been obtained as solution to a surface-curve intersection problem using optimization algorithm. Subsequently, the model has been generalized by employing NURBS to represent the curves whereby the cutting edges and angles can be altered simply by changing the control points or their respective weights. Using this methodology, the generic definitions of the conventional angles on the drill point have been derived and presented. The proposed model has been illustrated in MATLAB environment and validated experimentally for a conical and an arbitrary point geometry. The experiments show a good conformity with the theoretical evaluations. 相似文献
Journal of Statistical Physics - Self-exciting point processes are applied to various fields such as seismology, finance, neurophysiology, criminology, biology etc to model the clustering/contagion... 相似文献
Bacterial nanocellulose (BNC) is an indomitable biomaterial of utmost usage in different technological areas. Previously, the BNC production has been reported in the simplified bioreactors. Thus, pioneering bioreactor-assisted strategies are desirable for the commendable BNC production. Advanced bioreactors must be corroborated along with different bacterial strains to obtain creditable BNC yield. This study deals with BNC production in rotary disc bioreactor (RDBR) using Gluconacetobacter xylinus NCIM 2526 strain. RDBR-based production of BNC provided 189?±?14 gL?1 of wet BNC, i.e., equivalent to 6.6?±?0.3 gL?1 dry BNC yield in 10 days. However, in static cultivation mode, 56?±?12 gL?1 wet weight of BNC, corresponding to 2.4?±?0.4 gL?1 dry weight, was produced. Thus, BNC production was approximately 2.75 folds higher in RDBR than statically produced BNC from the same volume of the media. The sugar to BNC conversion yield (12.2?±?0.8%) was doubled in RDBR-based production as compared to static BNC production (6.2?±?1.4%) with efficient sugar consumption (90.0?±?3.3%). The maximum amount of BNC was produced at 7 RPM and pH 6. RDBR-based BNC showed a more hydrophilic nature than statically produced BNC. The RDBR might be appropriate for large-scale BNC production, especially for wet-end applications, as an ample amount of BNC can be produced from a single fermentation process. These BNC pellicles might have the potential for biomedical applications like wound dressings, biofacial masks, hydrogels, and tissue engineering scaffolds.
We report an operationally simple method to facilitate chemical protein synthesis by fully convergent and one-pot native chemical ligations utilizing the fluorenylmethyloxycarbonyl (Fmoc) moiety as an N-masking group of the N-terminal cysteine of the middle peptide thioester segment(s). The Fmoc group is stable to the harsh oxidative conditions frequently used to generate peptide thioesters from peptide hydrazide or o-aminoanilide. The ready availability of Fmoc-Cys(Trt)-OH, which is routinely used in Fmoc solid-phase peptide synthesis, where the Fmoc group is pre-installed on cysteine residue, minimizes additional steps required for the temporary protection of the N-terminal cysteinyl peptides. The Fmoc group is readily removed after ligation by short exposure (<7 min) to 20 % piperidine at pH 11 in aqueous conditions at room temperature. Subsequent native chemical ligation reactions can be performed in presence of piperidine in the same solution at pH 7. 相似文献
Journal of Thermal Analysis and Calorimetry - In the present framework, the simultaneous effect of rotation, magnetic field, heat source and local thermal non-equilibrium (LTNE) is investigated on... 相似文献
Effect of magnetic nanoparticles (nickel ferrite) doping on the dielectric and electro-optical properties of a ferroelectric liquid crystal mixture has been studied. In a doped ferroelectric liquid crystal mixture, dispersion of a small amount (0.25 wt.%) of nickel ferrite nanoparticles decreases the polarization and improves the response time compared to an undoped mixture. The significant changes in the polarization and response time are explained on the basis of dipole–dipole interaction and anchoring phenomena. Dielectric permittivity also increases with increasing the temperature of the SmC* phase and shows a reduction in dielectric loss in a doped sample. A Goldstone mode is clearly observed at ~200 and ~500 Hz in an undoped and a doped sample, respectively. 相似文献
In this framework, the novel analytical approach is presented to predict the dual solutions of Jeffery–Hamel (JH) transport model utilizing KKL (Koo–Kleinstreuer–Li) Al2O3 model with magnetic field, Ohmic heating and viscous dissipation. The predictor homotopy analysis method (PHAM) is applied to realize the existence of multiple solutions (bifurcation) for stretching/shrinking parameter and channel angle. It is observed that the dual solutions exist only for convergent channel. The eigenvalue problem is constructed to perform stability analysis which shows the physically stability of the upper branch. A numerical validation with Runge–Kutta–Fehlberg (RKF) shooting method using MATLAB is also carried out for verification. The Reynolds number is responsible to increase the velocity of fluid for both branches of the solution. For the increasing values of Ec and M, the Nusselt number decreases and increases respectively. 相似文献