Intensification of heat and mass transfer of the gas channel of the multi-temperature condensation filter

The principle of operation and features of hydrodynamics and heat-mass transfer in the working channel of a multi-temperature condensation filter for gas purification are described. Promising methods of gas flow purification using porous surfaces are described. The modeling and comparison of the laminar air flow in channels of various shapes: in a flat channel, in a channel with webs and in a spiral channel are performed. An analysis of their effectiveness is carried out.

Dynamically Tunable Friction via Subsurface Stiffness Modulation

Currently soft robots primarily rely on pneumatics and geometrical asymmetry to achieve locomotion, which limits their working range, versatility, and other untethered functionalities. In this paper, we introduce a novel approach to achieve locomotion for soft robots through dynamically tunable friction to address these challenges, which is achieved by subsurface stiffness modulation (SSM) of a stimuli-responsive component within composite structures. To demonstrate this, we design and fabricate an elastomeric pad made of polydimethylsiloxane (PDMS), which is embedded with a spiral channel filled with a low melting point alloy (LMPA). Once the LMPA strip is melted upon Joule heating, the compliance of the composite structure increases and the friction between the composite surface and the opposing surface increases. A series of experiments and finite element analysis (FEA) have been performed to characterize the frictional behavior of these composite pads and elucidate the underlying physics dominating the tunable friction. We also demonstrate that when these composite structures are properly integrated into soft crawling robots inspired by inchworms and earthworms, the differences in friction of the two ends of these robots through SSM can potentially be used to generate translational locomotion for untethered crawling robots.

Cross flow coupled with inertial focusing for separation of human sperm cells from semen and simulated TESE samples

A triplet spiral channel coupled with cross-flow filtration has been designed and fabricated in an effort to separate sperm cells from either semen or simulated testicular sperm extraction (TESE) samples.

Microfluidic recapitulation of circulating tumor cell–neutrophil clusters via double spiral channel-induced deterministic encapsulation

Circulating tumor cell (CTC)–neutrophil clusters are highly potent precursors of cancer metastasis. However, their rarity in patients' blood has made the researches being restricted so far, even more, in vitro...

Flow and heat transfer of supercritical LNG in spiral microchannel

Liquefied natural gas (LNG) is stable and safe, which is why the natural gas is usually liquefied before transported. The heat exchanger is widely used as the key component of vaporizing LNG, and it is composed of a large number of microchannels. This paper mainly analyzes the flow of supercritical LNG in a spiral microchannel, and compares the flow and heat transfer characteristic of spiral microchannel with different pitch. The result was indicative that with the lessen of pitch, the heat transfer is improved, but the flow characteristic is decreased. Compared with the straight channel, the spiral channel with appropriate pitch value can markedly improve the heat transfer properties, but has less effect on the flow characteristic. The discussion also includes the flow and heat transfer of microchannel with different mass flux and heat flux.