The active transport of micron sized 4′-pentyl-4-biphenylcarbonitrile (5CB) liquid crystal droplets propelled through an aqueous solution of tetradecyltrimethylammonium bromide (TTAB) as surfactant and glycerol as a solute, is investigated. On addition of glycerol, it was observed that the motion of active 5CB droplets exhibited a transition from smooth to a jittery chaotic motion. The motion was further found to be independent of the droplet size and the nematic state of 5CB. Upon conducting analogous experiments with Polyacrylamide (PAAM) as the solute, it was confirmed that a mere increase in viscosity cannot explain the transition. We propose the physicochemical interactions of glycerol with TTAB and 5CB, as the main cause responsible for the observed jittery motion. Presence of glycerol significantly enhances the rate of solubilization of the 5CB droplets resulting in a quicker re-distribution of the adsorbed TTAB molecules on the interface causing the droplet to momentarily stop and then restart in an independent direction. This hypothesis is supported by the time evolution of droplets size and interfacial velocity measurements in the presence and absence of glycerol. Overall, our results provide fundamental insights into the scheme of complex interactions emerging due to the presence of a non-reactive solute such as glycerol.

To fully harness the potential of artificial active colloids, investigation of their response to various external stimuli including external flow is of great interest. Therefore, in this study, we perform experiments on SiO2-Pt Janus particles suspended in an aqueous medium in a capillary subjected to different shear flow rates. Particles were propelled using varied H2O2 (fuel) concentrations. For a particular propulsion speed, with increasing shear flow, a continuous transition in the motion of active Janus particles (JPs) from the usual random active motion to preferential movement along the vorticity direction and then finally to migration along the flow was observed. This transition was accompanied by a significant decline in in-plane fluctuations of the particle trajectories. Another key observation is that the activity of JPs produces a delay in shear-induced rolling, which at moderate flow, allows the JPs to adopt a specific orientation, facilitating their migration along the vorticity direction. At higher flow rates, once shear flow overcomes the activity-induced resistance and initiates rolling, the probability of JPs adopting such preferred orientations reduces. Our analysis further revealed that these transitions are governed by a nondimensional quantity λ, which compares the relative strength of the shear-induced particle flow to the propulsion speed.

No abstract

No abstract

Replacement policy plays a major role in improving the performance of the modern highly associative cache memories. As the demand of data intensive application is increasing it is highly required that the size of the Last Level Cache (LLC) must be increased. Increasing the size of the LLC also increases the associativity of the cache. Modern LLCs are divided into multiple banks where each bank is a set-associative cache. The replacement policy implemented on such highly associative banks consume significant hardware (storage and area) overhead. Also the Least Recently Used (LRU) based replacement policy has an issue of dead blocks. A block in the cache is called dead, if the block is not used in the future before its eviction from the cache. In LRU policy, a dead block can not be remove early until it become LRU-block. So, we have proposed a replacement technique which is capable of removing dead block early with reduced hardware cost between 77% to 91% in comparison to baseline techniques. In this policy random replacement is used for 70% ways and LRU is applied for rest of the ways. The early eviction of dead blocks also improves the performance of the system by 5%.