Equivalences between localisations of categories provided by replacements

We give a characterisation of functors whose induced functor on the level of localisations is an equivalence and where the isomorphism inverse is induced by some kind of replacements such as projective resolutions or cofibrant replacements

Numerical Study of Frictional Drag Reduction Using Micro-bubbles in A Vertical Couette-Taylor System

In this work, we numerically study the reduction of frictional drag in a vertical Couette-Taylor system by using micro-bubbles. The silicon flow is in the annular gap between two concentric cylinders as the internal cylinder is rotating while the outer cylinder is stationary. Taylor vortices are formed between the cylinders and the rotational Reynolds number also varies from 700 to 4500. The carrier flow is silicone while air bubbles are constantly injected into the carrier phase at the bottom of cylinders and rise through the flow. By employing a discrete phase model and Euler-Lagrange approach, we investigate a two-phase turbulent flow. In this way, we study the distribution of the bubbles through the flow, which is acquired using numerical modeling. Our numerical results are in good agreement with the experimentally reported data for different values of Reynolds numbers. We also investigate the effect of injected air with a constant flow rate on the skin friction drag and on the drag coefficient ratio. Our numerical results illustrate a reduction of drag about 36% when microbubbles are injected into the system. This reduction can be achieved by the effect of the bubbles on the density of the fluid and transformed momentum

Prediction of hydraulic jump characteristics in a closed conduit using numerical and analytical methods

Abstract The hydraulic jump is an economical alternative to dissipate energy in the conduit and to reduce erosion at the culvert outlet. In the literature, very limited studies have been reported on the performance of hydraulic jump in a closed conduit. The innovation of this research is to employ a numerical method for the estimation of the hydraulic jump characteristics in a closed conduit with different positive slopes (S₀). The analytical method was used to develop several equations for hydraulic jump and the provided results were compared with the numerical method. The results indicate that the numerical method predicts the flow depth ratio after conduit with higher accuracy (error less than 5%) in comparison to the analytical method (error less than 10%). Furthermore, in the slope of 0.00, the energy loss increases by 16% with increasing the Froude number from 4.617 to 5.562 while this value is 23% and 22% for slopes of 0.01 and 0.02, respectively. Finally, several equations were developed for the prediction of hydraulic jump characteristics in terms of Fr₁, S₀, and conduit depth (D)

Design and constructing pBGGT Plasmid: a carrier plasmid for Betathalassaemia gene targeting

Background: Most of molecular biology studies depend on making gene constructs. Although commercial plasmids are widely used for this purpose, sometimes due to the nature of the restriction sites or need of multiple subcloning, usual restriction sites available in original multiple cloning sites (MCS) of the plasmids could not be easily used, if not impossible at all. Here, we report an easy and fast method to construct suitable plasmid with a new MCS for constructing a 16kb gene targeting plasmid.Methods: Firstly, the suitable MCS was designed by studying the sequence of desired gene fragments in Gene runner software. Two partial complementary 74 base long oligonucleotides were designed and constructed to make this MCS. The original pUC19 MCS was replaced with the new one by enzymatic digestion of the plasmid and removal of the MCS, followed by adding the two complementary oligonucleotides and ligating the construct and transforming it into Ecoli TOP10 F'. The new plasmid was then purified and sequenced by M13 forward and reverse primers.Findings: Synthesis of two 74 base polynuclotides was successful, and these polynucleotides formed a double stranded fragment which was successfully inserted between HindIII-EcoRI sites of pUC19. Analysis of intermediate step results showed successful progress of cloning reaction. Final analysis of the plasmid by restriction analysis and sequencing the MCS confirmed authenticity of the new plasmid.Conclusions: The method described here is a fast and easy way to make suitable plasmid out of commercially available plasmids. This process can considerably decrease the time and cost of plasmid construction. Availability of suitable restriction sites in proper order makes it possible to directionally clone the desired gene fragments which is more efficient and excludes screening steps for the right direction of the fragments. The plasmid reported herein is specifically tailored to insert different fragments of a beta-globin gene targeting construct