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A Versatile MEMS Quadrupole Platform for Portable Mass Spectrometry Using the First and Second Stability Regions | The Micro Gas Analyzer Program aims to develop portable, low-power, fast and low-false-alarm-rate gas analyzer technology for a wide range of applications. One of the subsystems of the gas analyzer is a mass filter. An array of micro-fabricated quadrupole mass filters is being developed for this purpose. The quadrupole... |
First Principles Optimization of Mass-producible Microscaled Linear Quadrupoles for Operation in Higher Stability Regions | In recent years, there has been a desire to scale down linear quad-rupoles. The key advantages of this miniaturization are the por-tability it enables and the reduction of pump-power needed due to the relaxation on operational pressure. Various attempts at making microscaled linear quadrupoles met with varying degrees ... |
A Single-gated Open Architecture carbon nanotube Array for Efficient Field Ionization | Mass spectrometers require a suitable ionizer to be able to discern the chemical composition of the sample that they are analyzing. Traditional ionizers for gases use either chemical ionization (CI) or electron impact ionization (EI). In the latter case, electrons from thermionic sources produce ions by colliding with ... |
A Fully Micro-fabricated Planar Array of Electrospray Emitters for Space-propulsion Applications | Electrospray thrusters work by extracting ions or charged droplets di-rectly from a liquid surface using an electrostatic field and accelerating them in that field to produce thrust [1]. This method could lead to more efficient and precise thrusters for space propulsion applications. Emission occurs from sharp emitter ... |
Carbon Nanotube Electron Sources for Space Propulsion Applications | Low-power, low-voltage, efficient field emission neutralizers for FEEPs [1], colloid thrusters [2], and other micro-propul-sion engines are attractive for nanosatellites because they do not use mass flowrate to operate, unlike more conventional neutralizing solutions such as hollow cathodes [3]. Electrons are field-emi... |
Carbon Nanotubes for Electrospray Nanofluidic Applications | Electrospray is the technique to soft-ionize liquids by applying a high electric potential to a liquid meniscus. The liquid menis-cus is deformed into a cone [1], and charged species are emit-ted from its apex. The emission can be solvated ions, charged droplets, or a mix of the two. This low-divergence charged species... |
A High-density Electron Source that Uses Un-gated Transistors for Ballasting | Electrons are field emitted from the surface of metals and semiconductors when the potential barrier (work function) that holds electrons within the metal or semiconductor is deformed by the application of a high electrostatic field. Field emitters use high aspect ratio structures with tips that have nanometer dimensio... |
Nanoelectromechanical Switches and Memories | The ability to change shape is a compelling attraction of molecu-lar semiconductors. Compared to rigid inorganic materials, mol-ecules are soft and malleable, and their conformational changes are essential to the functionality of biological systems. Applica-tions of nano-electro-mechanical (NEM) molecular devices in-cl... |
Exciton Coupled Surface Plasmon Resonance Biosensor | The development of portable and cost-effective biological sen-sors promises benefits to medical care, pharmaceutical testing, and the detection of biological warfare agents. Electronic devices are compact and readily integrated into microfluidic substrates, making them a promising alternative to today’s bio-detection r... |
Micromechanical Substrates for Reconfigurable cell culture | We have previously demonstrated the use of microfabricated cell culture substrates (Figure 1) to implement reconfigurable cell cul-ture (Figure 2) [1]. Specifically, we studied interactions between liver hepatocytes and supportive stromal cells. We found that preservation of liver-specific function depended on signalin... |
Aligned Multimask Patterning of Biomolecules and cells | Surface engineering of cell culture substrates has developed into a powerful tool for controlling multicellular organization at the micrometer scale. This new capability has brought valuable in-sight into the biological mechanisms by which the cellular micro-environment determines cell fate and function. However, studi... |
Collective Hydrodynamics and Kinetics of Sickle Cell Vaso-occlusion and Rescue in a Microfluidic Device | The pathophysiology of sickle cell disease, the first to be implicat-ed with a genetic origin, is complicated by the multi-scale nature of the processes that link the molecular genotype to the organis-mal phenotype. Here, we show that it is possible to evoke, control and inhibit the vaso-occlusive crisis event in sickl... |
Plasma-activated Inter-layer Bonding of Thermoplastics for Micro- and nano-fluidic Manufacturing | Plasma-activated polymer–polymer bonding is a promising way of encapsulating micro- and nano-fluidic channels across large substrate areas, without the substantial distortion of channel ge-ometries that can plague thermally- and solvent-assisted bond-ing. The process involves treating the surfaces to be bonded with an ... |
Environmentally Benign Manufacturing of Three-dimensional Integrated circuits | Along with scaling down in size, novel materials have been in-troduced into the semiconductor industry to enable continued improvements in performance and cost as predicted by Moore’s law. It has become important now more than ever to include an environmental impact evaluation of future technologies, before they are in... |
An Implantable MEMS Drug-delivery Device | A novel drug-delivery system based on MEMS technology is be-ing developed. This implantable microchip is capable of deliv-ering vasopressin, a known vasoconstrictor that can prevent or delay death by hemorrhagic shock [1]. The device is specially tailored to treat hemorrhagic shock in ambulatory settings and is intende... |
High Speed Three-dimensional Scanner for in vivo non-invasive Optical Biopsy using Two-photon Microscopy | We have recently demonstrated the modeling, design, and micro-fabrication process of a millimeter-scale, high-speed endoscopic scanner that is to be integrated at the distal end of an endomicro-scope [1]. The scanner system consists of (1) an active Silicon op-tical bench (SOB), as shown in Figure 1, which constrains, ... |
Electromagnetically-driven Meso-scale nanopositioners for nano-scale Manufacturing and Measurement | Nanopositioners – be they nano-, micro-, or macro-scale in physi-cal size – enable us to move large or small parts with nanome-ter-level or better precision. They therefore set the limits on our ability to measure, understand, manipulate, and affect physical systems. Six-axis small-scale nanopositioners enable a combin... |
Barcoded Microparticles for Multiplexed Detection | The detection of multiple targets in a single sample is important for many applications, including medical diagnostics, genotyp-ing, and drug discovery. The current approaches to multiplexing, such as planar arrays (such as DNA microarrays) and suspension (particle-based) arrays, require expensive or cumbersome means o... |
Single-molecule DnA Mapping in a Fluidic Device | The ability to controllably and continuously stretch large DNA molecules in a microfluidic format is important for gene-mapping technologies such as Direct Linear Analysis (DLA). We have recently shown that electric field gradients can be readily generated in a mi-crofluidic device and the resulting field is purely elo... |
DnA Dynamics in nanofluidic Devices | In dilute polymer solutions, the shape, motion, dynamic response, and solvent-interaction (HI) of single polymer molecules change when geometric constraints reach the length scales of the equi-librium polymer conformation. Our study seeks to understand these changes using double-stranded DNA as a model polymer and to u... |
Microfluidic Bubble Logic | Large-scale microfluidic integration promises to revolutionize the fields of biology and analytical chemistry. The “Lab-on-a-Chip” community has long sought the ability to precisely control very small volumes (nanoliters) of fluid packets . Current mechanisms for fluid routing depend on external control elements with n... |
Perfused Multiwell Tissue culture Plates for Development of Drug and Disease Models | A new platform for three-dimensional hepatic tissue engineering has been developed. It is based on the conventional multiwell tis-sue culture plate format but it allows the tissue to be continuously perfused with cell culture medium [1]. The new capability is achieved by a microfluidic perfusion system that re-circulat... |
A Patterned Anisotropic nanofilter Array for continuous-flow Separation of DnA and Proteins | Microfabricated regular sieving structures hold great promise as an alternative to gels to improve biomolecule separation speed and resolution. In contrast to the disordered gel porous network, these regular structures also provide well-defined environments ideal for study of molecular dynamics in confining spaces. How... |
Cell Stimulation, Lysis, and Separation in Microdevices | Quantitative data on the dynamics of cell signaling induced by different stimuli requires large sets of self-consistent and dynamic measures of protein activities, concentrations, and states of modi-fication. A typical process flow in these experiments starts with the addition of stimuli to cells (cytokines or growth f... |
Microreactors for Synthesis of Quantums Dots | We have fabricated gas-liquid, segmented-flow reactors with multiple temperature zones for the synthesis and the overcoating of quantum dots (QDs). In contrast to single-phase flow reactors, the segmented flow approach enables rapid mixing and narrow residence time distribution, factors which strongly influence the ult... |
Microfluidic Synthesis and Surface Engineering of Colloidal nanoparticles | There has been considerable research interest over the last de-cade in fabricating core-shell materials with tailored optical and surface properties. For example, core-shell particles of silica and titania have drawn attention due their potential for trapping light at specific frequencies. This optical property depends... |
Organic Synthesis in Microreactor Systems | Enhanced heat and mass transfer, reduced reaction volume, and the ability to run several experiments in parallel render mi-croreactors powerful instruments for scanning and optimizing chemical reaction conditions. Furthermore, the high mechanical strength and thermal conductivity of silicon microreactors permit the exp... |
Autothermal catalytic Micromembrane Devices for Portable High-purity Hydrogen Generation | The high efficiency and energy density of miniaturized fuel cells provide an attractive alternative to batteries in the portable-power-generation market for consumer and military electronic devices [1-3]. The best fuel cell efficiency is typically achieved with hydrogen, but safety and reliability issues remain with cu... |
Thermal Management in Devices for Portable Hydrogen Generation | The development of portable-power systems employing hydro-gen-driven solid oxide fuel cells continues to garner significant interest among applied science researchers. The technology can be applied in fields ranging from the automobile to personal elec-tronics industries. This work focuses on developing microreaction t... |
Microfluidic Systems for the Study of Vascular networks | Mechanical forces are important regulators of cell biology in health and disease. Cells in the vascular system are subjected to fluid shear stress, cyclic stretch, and differential pressure [1-3],[1-3],, and at the same time they receive multiple biochemical cues. All these factor into the integrated response of the ti... |
Patterning and Processing of Thermosensitive Hydrogels for | Hydrogels have been an active area of research for a variety of applications due to their ability to retain large volumes of water within their polymer gel networks. Stimuli-responsive hydrogels provide the added advantage of the ability to control the water retention by means of external stimuli. For example, N-isopro... |
A Large-strain, Arrayable Piezoelectric Microcellular Actuator by Folding Assembly | A low-power, piezoelectric, contracting cellular MEMS actuator has been developed that demonstrates a peak strain of 3% under a 10 V stimulus. Since the motion of the end effecter is linear and in-plane, the actuator can be arrayed in series to amplify the total stroke or in parallel to amplify the total force, as need... |
Thermal Ink Jet Printing of Lead Zirconate Titanate Thin Films | The ferromagnetic and piezoelectric properties of ceramic lead zirconate titanate (PZT) thin films have made PZT an appealing choice for micro-sensors and actuators. Significant work has been done integrating PZT with standard MEMS processes, including the development of PZT sol-gels for spin coating [1-2]. Crack-ing i... |
Piezoelectric Micro-power-penerator: MEMS Energy-harvesting Device for Self-powered Wireless corrosion-monitoring System | A novel thin-film, lead zirconate titanate Pb(Zr,Ti)O3 (PZT), energy-harvesting MEMS device is being developed for autono-mous wireless monitoring systems. It is designed to harvest en-ergy from parasitic vibrational energy sources and convert it to electrical energy via the piezoelectric effect. We envision that harve... |
Lateral-line-inspired MEMS-array Pressure Sensing for Passive Underwater navigation | A novel sensing technology for unmanned undersea vehicles (UUVs) is under development. The project is inspired by the lateral line sensory organ in fish, which enable some species to form three-dimensional maps of their surroundings [1-2]. The canal subsystem of the organ can be described as an array of pressure sensor... |
Fabrication of a Fully-integrated Multiwatt µTurboGenerator | There is a need for compact, high-performance power sources that can outperform the energy density of modern batteries for use in portable electronics, autonomous sensors, robotics, andsensors, robotics, and, robotics, and other applications. Building upon the results presented in [1], the current research is aimed at ... |
A Portable Power Source Based on MEMS and carbon nanotubes | There is a growing need for small, lightweight, reliable, highly efficient and fully rechargeable portable power sources. The focus of this project is the design and modeling of a system in which energy is stored in the elastic deformation of carbon nanotube (CNT)-based springs. The CNTs are coupled to a MEMS electric ... |
A MEMS Steam Generator | Previous work [1] has shown that MEMS technology has signifi-cant potential to create more compact, higher- performing hard-ware for chemical oxygen iodine lasers (COIL). In COILs, the laser medium is a flowing gas that must be pumped through the system at high mass flow rates to ensure proper system opera-tion. As a r... |
Microscale Singlet Oxygen Generator for MEMS-based cOIL Lasers | Conventional chemical oxygen iodine lasers (COIL) offer several important advantages for materials processing, including short wavelength (1.3 µm) and high power. However, COIL lasers typi-cally employ large hardware and use reactants relatively ineffi-ciently. This project is creating an alternative approach called mi... |
An Integrated Microelectronic Device for Label-free nucleic Acid Amplification and Detection | While there have been extensive advances in miniaturized poly-merase chain reaction (PCR) systems, progress on integrated mi-crofabricated readout mechanisms has been rather limited, and most systems rely on off-chip optical detection modules to mea-sure the final product. Existing optical detection platforms typi-call... |
Monitoring of Heparin and its Low Molecular Weight Analogs by Silicon Field Effect | Heparin is a highly sulfated glycosaminoglycan that is used as an important clinical anticoagulant. Monitoring and control of the heparin level in a patient’s blood during and after surgery is essen-tial, but current clinical methods are limited to indirect and off-line assays. We have developed a silicon field-effect ... |
Weighing of Biomolecules, Single cells and Single nanoparticles in Fluid | Nanomechanical resonators enable the measurement of mass with extraordinary sensitivity. Previously, samples as light as 7 zepto-grams (1 zg = 10-21 g) have been weighed in vacuum, and proton-level resolution seems to be within reach. Resolving small mass changes requires the resonator to be light and to ring at a very... |
Integrated System for cancer Biomarker Detection | There is evidence to suggest that the next generation of cancer-screening tests may employ not just one, but a small panel of less than ten biomarkers that together add statistical power to the de-tection of specific cancers. While immunoassays such as ELISA are well established for detection of antigen-based biomarker... |
Passive Microwave Transponders for Passive, Real-time, and High-sample-rate Localization | Passive surface acoustic wave (SAW) transponders have been used for RFID applications because of their zero-power and long-range (100m) capabilities. This work presents current research into utilizing SAW transponders for localizing objects. The SAW transponders have many advantages over existing localization solutions... |
Macroscopic Interfaces to Parallel Integrated Bioreactor Arrays | Macroscopic fluidic interfaces are important for improving the usability of microfluidic devices. For example, in our previously developed parallel integrated bioreactor arrays [1], two needle punctures were required to fill each fluidic reservoir, one for fluid injection using a syringe and another needle to vent the ... |
MIT-OSU-HP Focus center on non-lithographic Technologies for MEMS and nEMS | This newly formed center is part of an overall set of centers on MEMS/NEMS fundamentals supported by DARPA. The MIT-OSU-HP Focus Center aims to develop new methods for fabrica-tion of MEMS and NEMS that do not use conventional litho-graphic methods. The Center leverages the leading expertise of MIT and OSU in MEMS and ... |
A Micromachined Printhead for the Evaporative Printing of Organic Materials at Ambient Pressure | Organic optoelectronic devices are promising for many commer-cial applications if methods for fabricating them on large-area, low-cost substrates become available. Our project investigates the use of MEMS in the direct patterning of materials needed for such devices. By depositing the materials directly from the gas ph... |
Surface Micromachining Processes using non-lithographic Technologies | Conventional MEMS fabrication relies heavily on planar lithog-raphy and IC technology. While these techniques are well-suited for relatively flat devices such as the semiconductors, they are drastically limited in the design and fabrication of three-dimen-sional devices such as MEMS. From a commercial viewpoint, the se... |
Micromechanical Actuators for Insect Flight Mechanics | This project aims to develop MEMS actuators to aid in the study of insect flight mechanics. Specifically, we are developing actua-tors that can stimulate the antennae of the crepuscular hawk moth Manduca Sexta. The possible mechanosensory function of antennae as airflow sensors has been suggested [1], and recent discov... |
MEMS Micro-vacuum Pump for Portable Gas Analyzers | There are many advantages to miniaturizing systems for chemi-cal and biological analysis. Recent interest in this area has led to the creation of several research programs, including a Micro Gas Analyzer (MGA) project at MIT. The goal of this project is to develop an inexpensive, portable, real-time, and low-power appr... |
Microfabricated Electrodes for Solid Oxide Fuel cells | The solid oxide fuel cell (SOFC) is an energy-conversion device that produces electricity directly through the electrochemical re-action of hydrogen (H2) and oxygen (O2). The SOFC also allows utilization of hydrocarbons, such as methane (CH4), via internal reforming or direct electrochemical oxidation, giving these sys... |
A MEMS-relay for Power Applications | Contact travel and heat dissipation are important requirements of electrical power switching devices such as MEMS-relays and MEMS-switches. Whereas low-power MEMS-based RF switches have been vigorously studied, few studies have been reported on high-power MEMS-relays. This paper presents a MEMS-relay for power applicat... |
A Silicon-etched, Electrical-contact Tester | We are developing a bulk micromachined contact tester to inves-tigate the electro-tribological performance of micro- and nano- structured planar electrical contacts [1]. The test device features parallel, planar, nanometer-scale surface roughness contacts etched in silicon coated with thin conductive films. Contacts us... |
Microfluidic Studies of Biological cell Deformability and Rheology | It is well known that many hereditary or infectious diseases, as well as certain types of cancer, produce alterations in mechanical properties of human cells. In certain diseases, such as malaria, infected cells exhibit reduced deformability and increased cy-toadherance. Such changes alter the circulatory response of r... |
Phase change Materials for Actuation in MEMS | Phase change materials (Sb and Te alloys) are used for optical data storage in commercial phase change memories, such as rewrit-able compact discs (CD±RW) and rewritable digital video disks (DVD±RW, DVD-RAM) [1]. Recently, they have also shown high potential for the development of phase change random ac-cess memories (... |
Microfabricated Thin-film Electrolytes and Electrodes for Solid Oxide Fuel cells | There is growing interest in the microfabrication of electrodes for solid oxide fuel cells (SOFCs) in microionic devices [1]. Recently, we reported the fabrication of Pt/(Zr,Y)O2 (YSZ) nanocomposite electrodes by reactive magnetron co-sputtering [2]. Use of X-ray diffraction and X-ray photoelectron spectroscopy (XPS) c... |
Nanowire- and Microsphere-templated Gas Sensors | Novel materials synthesis techniques were used to fabricate nano-structured and macroporous semiconducting metal oxide (SMO) films exhibiting exceptionally high sensitivity to reducing and oxi-dizing gases, as compared to conventionally prepared specimens. Increased sensitivity resulted from an elevated surface area an... |
BioMEMS for control of the Stem cell Microenvironment | The stem cell microenvironment is influenced by several factors including cell-media, cell-cell, and cell-matrix interactions. Al-though conventional cell-culture techniques have been success-ful, they offer poor control of the cellular microenvironment. To enhance traditional techniques, we have designed a microscale ... |
Microfabricated Devices for Sorting cells Using complex Phenotypes | This research involves the development of numerous microfab-ricated sorting cytometer architectures for genetic screening of complex phenotypes in biological cells. Our various approaches combine the ability to observe and isolate individual mutant cells within surveyed populations. In this work we merge benefits of bo... |
Combined Microfluidic/Dielectrophoretic Microorganism Concentrators | This project focuses on the development of microfabricated mi-crofluidic/dielectrophoretic devices capable of concentrating micron-size particles from complex liquids. The concentrated particles of interest, such as pathogenic bacteria and spores, can then be delivered in small aliquots to the appropriate sensor for id... |
DEP cell-patterning for controlling cellular Organization | The ability to place cells at specific locations on a substrate is a useful tool to study and engineer interactions between cells [1], perform image-based cell selection [2], and create cell-based bio-sensors [3]. The ability to pattern with single-cell resolution is necessary in order to perform studies of single-cell... |
Iso-dielectric Cell Separation | Increased throughput in the techniques used to engineer new metabolic pathways in unicellular organisms demands similarly high throughput tools for measuring the effects of these pathways on phenotype. For example, the metabolic engineer is often faced with the challenge of selecting the one genomic perturbation that p... |
MEMS Vibration Harvesting for Wireless Sensors | The recent development of “low power” (10’s-100’s of µW) sens-ing and data transmission devices, as well as protocols with which to connect them efficiently into large, dispersed networks of indi-vidual wireless nodes, has created a need for a new kind of power source. Embeddable, non-life-limiting power sources are be... |
Design, Fabrication, and Testing of Multilayered Microfabricated Solid Oxide Fuel cells (SOFcs) | Microfabricated solid oxide fuel cells were investigated for por-table power applications requiring high energy densities [1]. The thickness of the electrolyte, the travel length of oxygen ions, was reduced down to ~150nm. The tri-layers (yttria-stabilized zir-conia (YSZ) as an electrolyte and platinum-YSZ cermet as ca... |
A Compact Flash X-Ray Source Based Upon Silicon Field Emitter Arrays | X-rays are used for non-destructive imaging in virtually every industry today. They enable doctors to make diagnostic decisions to quality assurance for electronics and industrial components. The machines that do these tasks are large, bulky, and occasionally slow due to the design of the X-ray system. Every X-ray imag... |
A Silicon Field Emitter Array as an Electron Source for Phase-controlled Magnetrons | Magnetrons are a highly efficient (>90%), high-power vacuum-based microwave source. In a magnetron, free electrons in vacuum are subject to a magnetic field while moving past open metal cavities, resulting in the emission of resonant microwave radiation. Current state-of-the-art magnetrons use a heated metal filament t... |
Acoustically-active Surface for Automobile Interiors Based on Piezoelectric Dome Arrays | The surfaces of automobile interiors can be rendered acoustically active by mounting on them thin, wide-ar-ea membranes with arrays of small acoustic transduc-ers. Each small, individually addressable transducer functions as a speaker or a microphone, and an en-tire pixelated acoustic membrane enables directional sound... |
The Scanning Anode Field Emission Microscope: A Tool for Mapping Emission Characteristics of Field Emitter Array Devices and Structures | We developed a scanning anode field emission micro-scope (SAFEM) for characterizing field emission array (FEA) devices and structures (see Figure 1). The SAFEM is designed to accurately and precisely scan and posi-tion a probing anode tip over emitter tips of an FEA and acquire maps of emitter tip current IE(x,y) and a... |
Highly Uniform Silicon Field-Emitter Arrays | Cold cathodes based on silicon field-emitter arrays (FEAs) have shown promise in a variety of applications requiring high-current-density electron sources. However, FEAs face a number of challenges that have prevented them from achieving widespread use in commercial and military applications. One problem limiting the r... |
CMOS Opto-nanofluidics | CMOS (complementary metal-oxide-semiconductor) foundries offers designers access to nanometer scale patterns, a suite of readout and interface circuits, and, more importantly, the capability to mass-manufacture their designs. These features of microelectronic CMOS foundries have been extensively utilized for photonic a... |
Increasing the Yield of Atmospheric Pressure Microsputtering for Fabrication of Agile Electronics | Additive manufacturing (AM) promises new, flexible production; however, while AM excels at creating structural parts, it cannot make functional objects well, e.g. multi-material structures such as electronic components and circuits. Sputtering, which removes material from a target atom-by-atom by using a plasma, is use... |
Silicon MEMS Compatible Bipropellant Micro Rocket Engine Using Steam Injector | Rocket engines miniaturized and fabricated using MEMS or other techniques have been an active area of research for two decades. At these scales, miniaturized steam injectors like those used in Victorian-era steam locomotives are viable as a pumping mechanism and offer an alternative to pressure feed and high-speed turb... |
Gated Silicon Field Ionization Arrays for Compact Neutron Sources | Neutron radiation is widely used in various applications, ranging from the analysis of the composition and structure of materials and cancer therapy to neutron imaging for security. However, most applications require a large neutron flux that is often achieved only in large infrastructures such as nuclear reactors and ... |
Silicon Field Emitter Arrays (FEAs) with Focusing Gate and Integrated Nanowire Current Limiter | The advent of microfabrication has enabled scalable and high-density Si field emitter arrays (FEAs). These are advantageous due to compatibility with complementary metal-oxide semiconductor (CMOS) processes, the maturity of the technology, and the ease in fabricating sharp tips using oxidation. The use of a current lim... |
Electron Transparent Anodes for Field Emission Cathodes in Poor Vacuum | Nanoscale Vacuum Channel Transistors (NVCTs) using field emission sources could potentially have superior performance compared to solid state devices of similar channel length. This is due to ballistic transport of electrons, shorter transit time and higher breakdown voltage in vacuum. Furthermore, there is no opportun... |
GaN Vertical Nanowires with Self-Aligned Gates for Field Emission Applications | Field emitters (FE), or namely vacuum transistors, are promising for harsh-environments and high-frequency electronics thanks to their radiation hardness and scattering-free electron transport. However, the stability and operating voltage still need improvement to enable circuit applications. To overcome these issues, ... |
3D-Printed, Miniature, Multi-material, Valve-less, Magnetically Actuated Liquid Pumps | Miniaturized pumps can be used to supply precise flow rates of liquid in compact systems. Numerous micro-fabricated positive displacement pumps for liquids with chamber volumes that are cycled using valves have been proposed. Pumps made via standard (i.e., cleanroom) micro-fabrication typically cannot deliver large flo... |
Measurement of the Condensation Coefficient of Water Using an Ultrathin, Nanoporous Membrane | In applications ranging from electronics cooling and power generation cycles to distillation, liquid-vapor phase change phenomena play a critical role. At their fundamental (kinetic) limits, evaporation and con-densation are dictated by the resistance to molecules crossing the liquid-vapor interface, which is quantifie... |
In-plane Gated Field Emission Electron Sources via Multi-material Extrusion | Field emission is the quantum tunneling of electrons to vacuum due to local high electrostatic fields; such high fields can be generated at a moderate voltage using nanosharp, high-aspect-ratio tips. Compared to thermionic counterparts, field emission cathodes consume less energy, respond faster, and can operate in poo... |
Additively Manufactured, Miniature Electrohydrodynamic Gas Pumps | A corona discharge is a self-sustained physical phenomenon induced around the sharper electrode of a diode due to sharply nonuniform electric fields within the interelectrode space. Ion propagation across such a space is accompanied by collisions with neutral particles, resulting in bulk fluid movement known as ionic w... |
3D-Printed Silver Catalytic Microreactors for Efficient Decomposition of Hydrogen Peroxide | Microreactors increase the surface-to-volume ratio of their reactants and by-products, resulting in faster, more efficient reactions and better heat transfer than in their non-miniaturized counterparts, leading to higher throughput per unit of reactor active volume and to better selectivity in the species produced by t... |
Management of Brine Effluent from the Desalination Plant | While large-scale desalination has been a mainstay in a country with a severe water shortage for many decades, management of high concentration brine effluent (> 50,000 TDS) has posed technological, economic, and environmental challenges. There are two research directions to treat the brine effluent effectively: (1) re... |
Reduced-order Modeling of Oil Transport in Internal Combustion Engines Based on Autoencoder | Reducing emissions of internal combustion engines is the major focus in the modern automotive industry. Lubrication oil leakage from the piston ring pack is critical to oil consumption and emission. The oil transport mechanism is not well understood due to the computational complexity of the oil motion and ring pack dy... |
A Four-terminal Nanoelectromechanical Switch Based on Compressible Self-assembled Molecules | Nanoelectromechanical (NEM) switches are under investigation as complements to, or substitutes for, CMOS switches owing to their intrinsic quasi-zero static leakage, large ON-OFF conductance ratio, and high robustness in harsh environments. For most NEM contact switches, a trade-off between high actuation voltage and t... |
Silicon Field Ionization Arrays Operating > 200 V for Deuterium Ionizers | Devices that can field-ionize gas molecules at low bias voltages are essential for many applications such as ion mobility spectrometry and highly selective porta-ble gas sensing. Field ionization consists of a valence electron of a gas atom or molecule tunneling through a potential barrier, commonly into a vacant energ... |
Highly Uniform Silicon Field Emitter Arrays | Cold cathodes based on silicon field emitter arrays (FEAs) have shown promising potential in a variety of applications requiring high current density electron sources. However, FEAs face a number of challenges that have prevented them from achieving widespread use in commercial and military applications. One problem li... |
High Current Density Silicon Field Emitter Arrays (FEAs) with Integrated Extractor and Focus Gates | Cold electron sources have been identified as alter-natives to thermionic emitters due to their lower op-erating temperature, instant response to the applied electric field, and their exponential current-voltage characteristics. With the advent of microfabrication, the generation of high electric fields around sharp em... |
A Silicon Field Emitter Array as an Electron Source for Phase Controlled Magnetrons | Magnetrons are a highly efficient (>90%), high-pow-er vacuum-based microwave source. In a magnetron, free-electrons in vacuum are subject to a magnetic field while moving past open metal cavities, resulting in resonant microwave radiation to be emitted. Current state-of-art magnetrons use a heated metal filament to the... |
Development of a Tabletop Fabrication Platform for MEMS Research, Development, and Production | A general rule of thumb for new semiconductor fabrica-tion facilities (fabs) is that revenues from the first year of production must match the capital cost of building the fab itself. With modern fabs routinely exceeding $1 billion to build, this rule serves as a significant barrier to entry for research and developmen... |
Is the Surface Wickability the Single Descriptor of Critical Heat Flux during Pool Boiling? | Enhancement and estimation of critical heat flux (CHF) are two of the most important research areas of pool boiling. It is well-known that microstructured surfaces can extend the limit of CHF up to ~250% higher than that of a flat surface. The mechanism for this enhance-ment has generally been accepted as the wickabili... |
Carbon Nanotubes Based-field Emitters by 3-D Printing | In field emission, electrons are ejected from a solid sur-face via quantum tunneling due to the presence of a high local electrostatic field. Compared to state-of-the-art thermionic electron sources, field emission cathodes consume significantly less power, are faster to switch, and could operate at higher pressure. Fi... |
Electron Impact Gas Ionizer with 3-D Printed Housing and NEMS Si Field Emission Cathode for Compact Mass Spectrometry | Mass spectrometry is widely used to quantitatively determine the composition of samples. However, the bulky size and high-power consumption of conven-tional mass spectrometry instruments limit their por-tability and deployability. One of the key components of a mass spectrometer (MS) is the ionizer. State-of-the-art el... |
Printed Piezoelectric Thin Films via Electrohydrodynamic Deposition | Piezoelectric components have found applications in a variety of fields including energy harvesting, biological and chemical sensing, and telecommunications. The creation of piezoelectric thin films has made possible the implementation of exciting devices that operate at higher frequency (a consequence of the reduction... |
Gravitationally-driven Wicking Condensation | Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Film-wise condensation, where the condensate completely covers the condenser surface, is prevalent in typical in-dustrial-scale systems. Dropwise condensation, where the condensate forms discrete liquid droplets, can i... |
Boron Arsenide Crystals with High Thermal Conductivity and Carrier Mobility | Overheating presents a major challenge in modern electronics industry due to the increasingly higher power density. High temperatures not only limit de-vice performance, but also greatly reduce reliability and lifetime. To effectively dissipate heat from an elec-tronic chip, materials with high thermal conductivity (k)... |
A Simple Fabrication Method for Doubly Reentrant Omniphobic Surfaces via Stress Induced Bending | We developed omniphobic, doubly reentrant surfac-es fabricated with a simple method suitable for use with traditional microfabrication processes. Intrinsic stresses in deposited layers of silicon nitride induced bending of a singly reentrant microstructure, creat-ing the doubly reentrant geometry. Due to the use of sta... |
Micro-engineered Pillar Structures for Pool Boiling Critical Heat Flux Enhancement | Increasing the performance of phase-change heat trans-fer phenomena is key to the development of next-gen-eration electronics, as well as power generation systems and chemical processing components. Surface-engineer-ing techniques could be successfully deployed to achieve this goal. For instance, by engineering micro/n... |
Superhydrophilic and Superhydrophobic Nanostructured Surfaces for Microfluidics and Thermal Management | Nanostructured features can be used to magnify the intrinsic hydro-phobicity or hydrophilicity of a material to create superhydropho-bic and superhydrophilic surfaces [1, 2]. There has been particular interest in these surfaces for a variety of applications including self-cleaning and drag reduction with superhydrophob... |
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