The numerical simulation of elastohydrodynamic lubrication has evolved in terms solution detail, speed and robustness. However, if EHL is to begin solve practical quantitative problems involving differences among lubricants, practitioners must utilize pressure-viscosity relationships their schemes that can describe real liquid response. authors with the simple empiricisms be used response piecewise over entire range from ambient glass transition. Then various free volume formulations are...

Advancement of focused electron beam-induced deposition (FEBID) as a versatile direct-write additive nanoscale fabrication technique has been inhibited by poor throughput, limited choice precursors, and restrictions on possible 3D topologies. Here, we demonstrate FEBID using nanoelectrospray liquid precursor injection to grow carbon pure metal nanostructures via direct decomposition electrochemical reduction the relevant achieving growth rates 105 times greater than those observed in...

As microelectronic system density continues to increase, cooling with conventional technologies become more challenging and is often a limiter of performance efficiency. The challenge arises due both large heat fluxes generated across entire chips packages, localized hotspots even higher flux. In this paper, nonuniform micropin-fin sinks are investigated for the integrated circuits power maps. Four heterogeneous samples were fabricated tested in single-phase experiments deionized water...

Abstract Liquid failure has been observed in low Reynolds number (Stokes) shear flows where reduction of the hydrodynamic pressure should not occur. Cavitation Stokes implications lubrication, polymer processing, and rheological measurements. Such cavitation can be predicted by a principal normal stress criterion (PNSCC). We present results direct experimental test PNSCC. Imaging events suggests that is gaseous originates from preexisting nuclei. Crevice‐stabilized gas nuclei are assumed,...

This paper reports on novel thermal testbeds with embedded micropin-fin heat sinks that were designed and microfabricated in silicon. Two arrays presented, each a nominal pin height of 200 μm diameters 90 30 μm. Single-phase two-phase testing the array performed using de-ionized (DI) water as coolant. The tested mass flow rate was 0.001 kg/s, flux ranged from W/cm2 to 470 W/cm2. maximum transfer coefficient reached 60 kW/m2 K. results obtained two compared analyzed, showing density...

As integration levels increase in next generation electronics, high power density devices become more susceptible to hotspot formation, which often imposes a thermal limitation on performance. Flow boiling of R134a two microgap heat sink configurations was investigated as solution for management: bare and inline micro-pin fin populated microgap, both with 10 μm gap height, were tested terms their ability dissipate fluxes approaching 5 kW/cm2 at the source. Additional parameters include mass...

Abstract Brain temperature is an important yet understudied medical parameter, and increased brain after injury associated with worse patient outcomes. The scarcity of methods for measuring non-invasively motivates the need computational models enabling predictions when clinical measurements are challenging. Here, we develop a biophysical model based on first principles energy mass conservation that uses data from magnetic resonance imaging individual tissue vessel structure to facilitate...

We describe the DRILL (dry ion localization and locomotion) device, which is an interface for electrospray ionization (ESI)-mass spectrometry (MS) that exploits a swirling flow to enable use of inertial separation prescribe different fates electrosprayed droplets based on their size. This source adds new approach charged droplet trajectory manipulation which, when combined with hydrodynamic drag forces electric field forces, provides rich range possible operational modes. Here, we...

Salt removal is a prerequisite for electrospray ionization mass spectrometry (ESI-MS) analysis of biological samples. Rapid desalting and low volume connection to an tip are required time-resolved measurements. We have developed microfabricated device that meets both requirements, thus providing the foundational technology piece transient ESI-MS measurements complex liquid specimens. In device, sample flows in channel separated from higher flow rate, salt-free counter solution by...

Polyoxometalates (POM) have been deposited onto carbon nanotube (CNT) electrodes using benchtop ion soft landing (SL) enabled by a vortex-confined electrohydrodynamic desolvation process. The device is based on the dry localization and locomotion (DRILL) mass spectrometry interface of Fedorov co-workers. By adding electrospray emitters, heating gas, operating at high gas flow rates, it possible to obtain stable currents up -15 nA that are ideal for deposition. Coupled with ambient optics,...

Capillaries coated with hydrogel on their inner wall fill <italic>via</italic> a stick–slip dominated process, elastocapillary pining halting water meniscus motion, and polymer softening increasing surface wettability initiating slip events.

There are a number of emerging electronic applications that thermally limited and may exhibit high overall power dissipation ("background") combined with local very fluxes ("hotspot"). We have batch fabricated microfluidic heat sink specifically designed to address both levels removal. A microgap for hotspot cooling micropin-fins sequentially deep etched in silicon substrate. The is sealed by bonding another layer the coolant injected into from two distinct ports dissipate generated...

Large-scale manufacturing of therapeutic cells requires bioreactor technologies with online feedback control enabled by monitoring secreted biomolecular critical quality attributes (CQAs). Electrospray ionization mass spectrometry (ESI-MS) is a highly sensitive label-free method to detect and identify biomolecules, but extensive sample preparation before analysis, making application ESI-MS challenging. We present microfabricated, monolithically integrated device capable continuous...

We present an experimental study of two phase flow refrigerant R245fa in a pin fin enhanced microgap for range heat fluxes between 151 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 326 . The gap has base surface area 1cm × and height 200 μm. An array hydrofoil shaped fins covers from bottom top the microgap. have chord length, longitudinal pitch, transversal pitch 75μm, 450μm 225μm, respectively. On back side chip, four...

We have visualized two phase flow cooling of R245fa refrigerant in a 1 cm × 200 µm microgap, equipped with circular pin-fins. The device has the microgap sparse pin-fin arrangement transverse pitch, longitudinal and diameter 225 µm, 75 respectively. On back side chip, four integrated platinum heaters are fabricated arranged series. is installed closed loop that pressurized. inlet subcooled at elevated pressure. Flow boiling obtained for range heat flux values between 7 W/cm2 to 34 W/cm2....

An evaluation of two approaches to localized hotspot cooling is conducted through both numerical modeling and experimental demonstration, with the advantages limitations each approach highlighted. The first approach, locally increasing density pins in a micro pin fin heat sink, was shown deliver factor enhancement effective transfer coefficient by doubling near hotspot. This simpler maintaining temperature uniformity eliminates need for specific fluid routing delivery, also has minimal...

The use of combined reaction-separation processes in steam methane reforming (SMR) has recently received significant attention as an enticing route to meet the challenging requirements distributed hydrogen production for fuel cell vehicles. While many investigations recent literature focus solely on either CO2 adsorption or selective H2 membrane permeation reduce reactor footprint and temperature required drive endothermic reaction continuous flow reactors, CHAMP-SORB is a new variable...

Simple order-of-magnitude relationships predicting heat transfer in limiting cases of combined convection and radiation problems boundary layer flows are found using the method scale analysis. Key nondimensional groups developed that help identify fundamental interactions between thermal modes for two laminar, two-dimensional from a semi-infinite vertical wall. The first case is gray wall with specified flux to surrounding non-participating medium considers both forced natural effects....