In this work, we introduce the novel technique of inchip drop on demand, which consists in dispensing picoliter to nanoliter drops on demand directly in the liquid-filled channels of a polymer microfluidic chip, at frequencies up to 2.5 kHz and with precise volume control. The technique involves a PDMS chip with one or several microliter-size chambers driven by piezoelectric actuators. In this ...

Cutting processes are unstable machining processes. The influence of the instability on the deformation mechanism that leads to the chip formation at the atomic scale is analysed in this paper. Fundamental aspects of the crystalline networks deformation are underlined by using molecular dynamics technique applied to the microscopic level of the deformed material and are defined as basic instabi...

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only increased ploughing forces but also an increase in ...

In this study, a novel approach of high speed scratching is carried out on silicon (Si) wafers at nanoscale depths of cut to investigate the fundamental mechanisms in wafering of solar cells. The scratching is conducted on a Si wafer of 150 mm diameter with an ultraprecision grinder at a speed of 8.4 to 15 m/s. Single-point diamonds of a tip radius of 174, 324, and 786 nm, respectively, are use...

This paper presents an investigation of the mechanism of the brittle–ductile cutting mode transition from the perspective of the mechanics. A mechanistic model is proposed to analyze the relationship between undeformed chip thickness, deformation, and stress levels in the elastic stage of the periodic chip formation process, regarding whether brittle or ductile mode deformation is to follow the...

In this work, we introduce the novel technique of in-chip drop on demand, which consists in dispensing picoliter to nanoliter drops on demand directly in the liquid-filled channels of a polymer microfluidic chip, at frequencies up to 2.5 kHz and with precise volume control. The technique involves a PDMS chip with one or several microliter-size chambers driven by piezoelectric actuators. Individ...

Aquaporin channel-forming integral protein (CHIP) is the first characterized water channel protein (genome symbol AQP1), but the molecular structure of the aqueous pathway through CHIP remains undefined. The two halves of CHIP are sequence-related, and each has three bilayer-spanning domains with the motif asparagine-proline-alanine (NPA) at residues 76-78 (in cytoplasmic loop B) and 192-194 (i...

A finite element model is presented to simulate chip breaking when orthogonal turning medium carbon steel with a grooved cutting tool is used. The chip formation, chip breaking, cutting force, stress, strain and temperature are simulated by the thermo-elastic-plastic finite element method, using commercial finite element software. The cutting process is simulated from the initial to the steady-...

Novel on-chip fluid control strategies, on-demand formation of arbitrary microchannels and parallel control of multiple microvalves were successfully demonstrated by means of computer-controlled micropatterned light irradiation of a photoresponsive hydrogel sheet.