Autonomous microfluidic devices are essential for the long-term development of versatile biological and chemical platforms. However, creating effective control mechanisms has proven a significant challenge. To address this challenge, investigators at University of California at Berkeley have developed a single-layer microfluidic device, with optofluidic circuitry.The single-layer microfluidic device is manufactured from optofluidic lithography circuits built from guided micro-structures. These micro-structures are constructed in situ via optofluidic lithography. The devices built using this innovative fabrication approach have such features as rotational and linier gears, ratcheting, resistors, diodes, capacitors and other key functional elements. (more...)

Researchers at the University of California, Irvine have developed a new hybrid tissue that is capable of self renewal. This new hybrid tissue may be used as replacement heart valve leaflets and may also be used for other tissue constructs like blood vessels. (more...)

Dehumidifier and condenser applications (where water is condensed onto a chilled surface) are common in power plants, desalination plants, chillers and heat exchangers. In these applications, condensation can be enhanced with an alternating hydrophilic-hydrophobic pattern on the condensation surface. This patterning has been implemented using polymers, self-assembled monolayers and other non-conducting materials. These approaches create chemically heterogeneous surfaces that have limited lifetimes -- due to the thickness and durability of the film.To address this situation, researchers at UC Berkeley have developed a surface with alternating hydrophilic-hydrophobic patterning that promote dual and simultaneous modes of condensation -- filmwise and sustained dropwise condensation -- on a chemically homogenous conducting material (metal substrate) -- which is the material of choice for condenser applications. This innovation is achieved with a practical and scalable technique of surface machining or roughening based on the preferred dimensions of the pattern. The resulting chemically homogenous, conductive substrate is important for maintaining a substrate with high thermal conductivity and doesn't add any thermal resistance that would impede the condensation heat transfer.   (more...)

This invention is on a new practical method for discovering errors in compilers, interpreters, database engines, and software analysis and transformation tools in general (such as obfuscators and static analyzers). (more...)

Berkeley researchers have designed a methodology to solve in real-time linear programming (LP) problems with an analog circuit. Despite continued advancement of digital computers, the task of solving LP in very short times (e.g. 1 MHz for MPC based control of fast systems) remains challenging. Due to lack of temporal overlap between analog computation and MPC, there have been few investigations in applying analog computation towards MPC problems or LP problems. Using this technology, solution to real-time optimization problems can be achieved at 6 microseconds and ongoing work aims to reduce it to a few nanoseconds, which is lower than any current method known to our investigators. (more...)

An innovative and affordable vegetative cool roof technology that uses the shading capacity of plants to reduce solar heat gain to roof surfaces and provides an alternative lightweight and more affordable green roof system. The technology serves to reduce the building's energy and water use. (more...)

University of California researchers have developed a method for reducing electronic 1/f noise in graphene devices used for high speed applications and biological and chemical sensors.  Using a novel method of irradiating the channel regions of graphene devices with electron beams with proper irradiation dosage, the 1/f noise in a graphene device is suppressed.   (more...)

Researchers at University of California, Davis have discovered a nanophotonic device that reduces limits of detection of an immunoassay by orders of magnitude. (more...)

As part of the Tacky Dot® donation, the University is offering for commercialization the process and product of mounting free-flowing particles having a support surface with an array of tacky areas which have a size and bonding strength suitable for the adhesion of either one or two particles (see patent 5,356,751). The size of the particles can be between 5 and 2000 microns. (more...)

Traditional inertial MEMS sensor architectures rely on amplitude detection, where the inertial input produces an Amplitude Modulation (AM) of the sensor proof mass displacement. This creates traditionally irresolvable limitations on the device gain-bandwidth and dynamic range. Also, fundamental limitation of the described conventional architecture comes from the necessity to precisely measure extremely small analogue signals. In the best case scenario, AM readout with pre-selected low-noise electronic components can only achieve a resolution of 1e-6, with a practical limit of 1e-5. This imposes a fundamental limitation on the dynamic range and output stability and precludes MEMS gyroscopes and accelerometers from many potential applications. Also, this common AM architecture creates traditionally irresolvable limitations on the device gain bandwidth and dynamic range. The conventional AM-based inertial sensor operation is also sensitive to temperature, resulting in significant response drifts over ambient temperature and pressure variations. The stability of the analogue signal reference is limited by 1e-6, a fact that creates irresolvable limitations on the AM devices stability. UCI researchers have developed a temperature and vibration immune, inherently quasi-digital, multi-axis MEMS Inertial Measurement Unit (IMU), with ultra-high precision, stability, with wide dynamic range and wide measurement bandwidth. The proposed system is based upon Frequency Modulated (FM) accelerometers and gyroscopes. Due to the inherent FM nature of the system, it is expected to provide resolution and stability unprecedented in conventional inertial MEMS devices. The proposed IMU provides a unique differential frequency measurement technique and enables simultaneous detection (and decoupling) of the true inertial inputs (angular rate and acceleration) as well as the temperature distribution across the chip-scale system. In this approach, the IMU becomes its own thermometer, eliminating the commonplace need for thermal calibration and issues with thermal lags and hysteresis. Also, the proposed system architecture is robust against mechanical and electromagnetic interferences due to the inherent advantages of frequency modulated signals (quasi-digital) compared to amplitude modulated signals (analog). (more...)

An improved OCR engine for real-world text reading using a mobile phone or other hand-held mobile device. The copyrighted software can capture words from street signs, grocery store placards, and a host of other non-standard print references and quickly interpret them with its built-in reference dictionary. The conversion to actionable information is fast and the application thin, enabling easy adoption in a mobile setting. (more...)

Advanced neural stimulator designs consume power and produce unwanted thermal effects that risk damage to surrounding tissue. (more...)

Nucleic acid quantification is extremely important in the field of biological research and has been used for studies of genes, genomes, chromosomes, and viruses. While current methods for nucleic acid quantification are powerful, new methods may provide researchers with increased accuracy, higher resolution, and a larger dynamic range. Researchers at the University of California, Irvine have developed a novel device and method that can achieve ultra-high dynamic range PCR over 10-12 orders of magnitude. The device can be used on large sample volumes (50 uL) that contain as little as a single nucleic acid strand to as high as theoretically possible. In addition, the device and method can provide higher dynamic ranges with exceptionally higher resolution and accuracy than any prior methods. (more...)

Microfluidic technologies have revolutionized the field of cell biology by enabling the development of integrated “lab on a chip” systems that are capable of integrating multiple laboratory steps onto a single device. An important cell manipulation process that has been the focus of microfluidic researchers is the ability to switch cells of interest to multiple downstream processes for further analysis. As a result, multiple microfluidic switches for particles and cells have been developed and integrated into micro Fluorescence Activated Cell Sorting (μFACS) systems, including electro-osmotic flow (EOF), dielectrophoresis, microfabricated valves, external valves, and optical tweezers. However, many of these current microfluidic switches have drawbacks such as low throughput, low cell recovery, complex off-chip setups, and high voltages. Novel microscale cell/particle sorting systems would be extremely useful components to integrate into next-generation microfluidic devices for cell biology applications. Researchers at the University of California, Irvine have developed a novel Lateral Cavity Acoustic Transducer (LCAT) cell/ particle switch that is capable of deflecting cells and particles to downstream collection channels. The device is easily fabricated, can achieve switching rates up to 800 particles per second, achieves approximately 94% cell viability, has low energy consumption, and is suitable for integration into a complete microfluidic sorting platform. (more...)

Researchers at the University of California, Irvine, have developed a novel “passive” microfluidic architecture designed to sort droplets. (more...)

With progress slowing down in improving multimedia visual and audio quality, there is an increased need for enhancing the viewer experience through other means. Recent research has shown increased emotional immersion, sense of presence, and sense of realism when tactile stimulation accompanies movies. Tactile stimulation can be combined with many entertainment applications, including video games, television, home theater, virtual reality simulation, music, and social interaction.  However, current tactile stimulation devices used for entertainment purposes face issues with ease of use and the ability to administer stimulation in various intensities on various body areas. There is thus a need for a versatile, programmable, non-invasive, and easy-to-setup tactile stimulation device that can be adapted for various entertainment applications.  (more...)

A method for wafer bonding Group-III nitride cells to non-Group-III nitride cells to create a multi-junction solar cell with improved efficiency. (more...)

Control of wetting properties has been intensely investigated for applications in diverse fields, from microfluidics to contamination prevention. Superhydrophobicity, normally achieved through structural or chemical alterations, allows for free movement of water across a surface due to its high contact angle and low sliding angle. Many of the fabrication techniques used to prepare superhydrophobic surfaces, which include photolithography, chemical vapor deposition, and self-assembled monolayers, are time consuming and costly. A simpler and more rapid method to create superhydrophobic surfaces will allow for its increased use in fields such as microfluidics and biomaterials. Researchers at the University of California, Irvine have developed a robust, tunable, rapid, reproducible, and inexpensive method for creating superhydrophobic surfaces with hierarchal nano- and microscale structures molded into various hard plastics. The method involves a purely structural modification that is free of chemical additives. In addition, the technique can also be used to create hydrophilic regions embedded within the superhydrophobic regions to easily fabricate open-channel microfluidic devices. (more...)

Microfluidic devices have applications in a wide variety of areas, including molecular biology, DNA analysis, and lab-on-a-chip systems. Many microfluidic devices incorporate systems that utilize centrifugal force and pneumatic pressure of compressed air to reverse the flow direction on a rotating platform. A centrifugal system that allows for continuous flow without the use of compressed air will be very useful. Researchers at the University of California, Irvine have developed a centrifugal microfluidic system that allows for uniform continuous flow reciprocation motion in a microchannel without an external source of pressure. This system requires lower operational rotational velocities and promotes more effective liquid reciprocation than currently available methods. (more...)

With the development of wireless sensors networks, there is an urgent need for compact power sources. The challenge to developing planar devices to meet these needs is the integration of the electrodes’ high surface area material necessary to ensure a high capacitance. with acceptable performances.  To meet this challenge, investigators at University of California at Berkeley have developed polymer derived porous carbon material for on-chip energy storage devices  The high porosity of the fabricated material leads to a high specific capacitance and hence, high energy density.  The process is highly compatible with planar micro-/nanotechnology. The material is stable at high temperature (< 900°C), and can be used to fabricate on-chip storage devices such as microsupercapacitors able to operate at high temperature. (more...)

Leveraging from microfabrication techniques originally developed for the microelectronics industry, researchers have been able to create simple designs such as well-defined and repetitive patterns of grooves, ridges, pits, and waves.Techniques such as photolithography, electron-beam lithography, colloidal lithography, electrospinning, and nanoimprinting are popular methods for fabricating micro and nano topographical features.However, the need for large capital investments and engineering expertise has prevented the widespread use of these fabrication methods in common biological laboratories.Researchers at the University of California, Irvine have developed an ultra-rapid, robust, and inexpensive fabrication method to create multiscaled grooves, ranging from micron to nanometer in size, as biomimetic cell culture substrates.This method only takes a few minutes to perform and does not require any metal deposition.In addition, the size of the nanowrinkles is easily tuned for a multitude of biological applications. (more...)

Photolithography, an essential process in the fabrication of integrated circuits, has undergone continuous advancements that allow patterning of nanometer sized features. For example, features as small as 50 nm can be made by using excimer lasers with wavelengths of 248 nm and 193 nm (i.e., deep ultraviolet light). However, it is not always feasible for scientists to use the short wavelength lasers because they are expensive. A method that allows for high resolution photolithography without large capital expenses will be very useful. Researchers at the University of California, Irvine have developed a photolithography method that allows for high resolution patterning. By using this method, one can get a 20-fold improvement in the limit of resolution in comparison to the inherent resolution of “top-down” processing. In addition, the method is easy to use, inexpensive, and does not require sophisticated instrumentation. (more...)

A very efficient Vertical-Cavity Surface-Emitting Laser (VCSEL) applicable to optoelectronics, specifically optical interconnects. (more...)

The present invention relates to a new voltage sensor that would allow for an economical way to achieve distributed monitoring of the nation’s power line infrastructure without posing a hazard to field operators. (more...)

Researchers in UCI’s Department of Environmental & Civil Engineering have developed a revolutionary solution to the problem bulking and foaming organisms found in wastewater treatment systems. Their kit provides a fast, accurate and extremely cost effective method of identifying these troublesome organisms to allow rapid treatment prior to the onset of costly post “bloom” remediation. (more...)

As powered electrical and mechanical devices have continued to be miniaturized, it has become increasingly important to limit the temperature rises of vulnerable components such as integrated circuits, small mechanical elements and light sources. The conventional passive heat transfer method most commonly used is to simply put a set of fins in the heat transfer path from the source of heat (e.g., a packaged device) to a region where a gaseous or liquid coolant contacts the fins, becomes heated, and then is allowed to contact or mix with a large volume of gas or liquid that is cooler. These finned heat transfer approaches have limits, and therefore researchers at UC Berkeley have developed a means of augmenting this conventional passive heat transfer with supplementary actively powered mechanisms. This novel approach increases the rate of contact and mixing -- and thereby, the rate of heat removal. The approach is appropriately sized (i.e., miniature), energy efficient, quiet, inexpensive, and has a long lifetime.  (more...)

An FM gyroscope with inherently digital output. Tradeoff between quality factor and range and bandwidth is eliminated, allowing the use of ultra-high Q for improved noise performance without limiting the bandwidth and range. Temperature is self-sensed and self-calibrated, so the hysteresis and lags are eliminated. (more...)

Baluns are extensively used for single-to-differential conversion of analog/RF/millimeter-wave/broadband signals in integrated transceivers as well as test/measurement equipment setup. Passive baluns do not consume dc power, but suffer from signal attenuation as well as being limited to narrow bands. Active baluns provide power gain and wideband operation while consuming power from dc power supply. This invention is a novel design of an active balun that improves voltage gain and linearity without sacrificing power, bandwidth or physical area. (more...)

Researchers at the University of California, Irvine have developed an automated microfluidic device that traps different cell populations in different chambers based on the cells’ dielectric properties. The device consists of one main channel with individual sets of electrodes in three or more different chambers. Each set of electrodes generates a non-uniform electric field that traps and therefore separates a heterogeneous cell population at different frequency ranges due to dielectrophoretic forces. These trapping chambers are intersected by channels perpendicular to the main channel. Flow along the different channels is controlled by actuating pneumatic valves. To retrieve the cells, the flow in the main channel is stopped and flow from the perpendicular channels is initiated. The trapped cells are then captured into collection wells. (more...)

Mass-producible vacuum photon detector without solid metallic electrodes or feedthroughs and with minimized content of radioactive elements, forming arrays without dead area for light detection. (more...)

A Michelson interferometer is formed by discrete optical elements mounted to a frame that holds a pendulum suspended from a monolithic flexure. The interferometer measures the displacement of the end of the pendulum with respect to the frame. Optical fibers link the optics to a laser, photodetectors, and a digitizer for signal processing at the other end of an optical fiber cable. The system is robust and ideal for oil and gas borehole sensing, as only optical components are exposed to the harsh working environment with all electronics safely housed at the surface. (more...)

Throughout the world, there is a growing need for energy efficient housing solutions. The need is particularly strong in developing countries located in tropical climates, where the cost of energy used for temperature and humidity control is very high. As these climates are often prone to flooding, there is also a need for low-cost, energy efficient emergency housing. The bulk of energy is spent on compensating for heat and cooling losses that occur through the building envelope � the outer shell of a building that protects the indoor environment. Most current building envelopes have separate controls for environmental flows such as humidity, cooling, and light transmission that lack precision and are difficult to calibrate. Climatic self-regulation of building envelopes that can reduce the need for artificial space conditioning is highly relevant to develop. Through a pioneering interdisciplinary collaboration between bioengineering and architecture, researchers at UC Berkeley developed a new sensor technology for external building membranes that can actively respond to environmental changes, and provide automated control of moisture and temperature. The system for Self-Activated Building Envelope Regulation (SABER) is inspired by new understanding of moisture barrier and heat transfer in plants. SABER utilizes optomechanical and hygrothermal sensor/actuator networks build onto a thin film membrane, which can replace the expensive and large mechanical control systems. (more...)

Solar thermal concentrators are used by concentrating solar radiation and converting it to high-temperature steam or gas to drive a turbine or motor engine for power generation. A wide range of concentrating technologies has been developed. However, it remains challenge and demand to optimize the overall thermodynamically efficient solar thermal systems in achieving the engineering optimum. Evacuated solar thermal tubes are widely used as solar collectors and come in a variety forms. An innovative design methodology based on the combination of optimal nonimaging optics and heat transfer techniques produces a remarkable effective non tracking solar collector for high temperature. It is promising to be well applied in balancing the competing engineering constrains in constructing the collector. (more...)

Solar collectors have been designed differently with various desired performances for application in solar energy generation. Solar thermal collector is designed to collect heat by absorbing sunlight. Solar electric generation system is designed to generate electricity directly from sunlight using photovoltaic (PV) materials. Solar collectors may employ light concentrators to concentrate solar light onto the energy transducer for effective energy conversion, and many forms of concentrators have been developed in reaching higher concentration. Concentrators may be imaging or nonimaging. To reduce cost and increase the overall efficiency of a solar system, one promising technology is to combine heat and electric power generation. (more...)

Alginates have been used for decades for the encapsulation of biological molecules, cells and chemicals. The traditional encapsulation process involved dissolving or dispersing the active agent in a sodium alginate solution, forcing the solution through an orifice to form a droplet which was then cross-linked by contact with a calcium chloride solution. This process was not easily scaled-up and was limited to particles larger than 500 μm. Spray-drying would be a commercially viable process to form a calcium alginate matrix particle in the size range of 10 – 20 μm; however, one would have to find a way of cross-linking the sodium alginate solution during atomization. Researchers at the University of California Davis have developed a method that accomplishes this by spray-drying an aqueous formulation that contains sodium alginate, a calcium salt that is only soluble at reduced pH and an organic acid that has been neutralized to a pH just above the pKa with a volatile base. Under these conditions, the calcium salt is insoluble and calcium ions are not available for cross-linking. The solution in this fluid state is pumped through the nozzle of the spray dryer, where it is effectively atomized. Upon atomization, the volatile base is vaporized, which reduces the pH (hydrogen ions are released into solution) and in turn releases calcium ions from the calcium salt that cross-link the alginate. The incorporation of an additional polymer to the formulation allows for the control of hydration properties of the particles to control the release of the encapsulated compounds. This same process can be used for encapsulation using soy protein. (more...)

Exhaust heat from high temperature fuel cells is used to reform the fuel to a gas turbine. The unconverted energy from a fuel cell is introduced into the gas turbine thereby increasing the overall plant efficiency and the specific power output of the gas turbine. (more...)

A fuel cell is an electrochemical device similar to a battery that converts chemically bound energy directly into energy. There are various types of fuel cells and the solid oxide type fuel cell has the advantage of a high operating temperature which results in a high exhaust temperature. Researchers in UCI’s Advanced Power and Energy Program have utilized this high exhaust temperature to maximize the power efficiency and quality via recycling gas through the SOFC system. (more...)

Researchers at UCI’s MicroSystems Laboratory have developed a process and design to form a highly reflective coating for the angled sidewalls of a miniature cavity for vapor cells. These coatings are for micro-optical elements or micro-optical-electrical-mechanical-systems of MOEMS. The applications of these coatings include miniaturized atomic clocks for ultra precision time keeping and magnetometers for the sensing of magnetic fields. (more...)

Interference in wireless communication systems is an ongoing problem. In the past, TDMA, FDMA, CDMA or other multiple access methods have been applied to avoid interference. The problem with these approaches is that they waste valuable bandwidth resources. Researchers in UCI’s Engineering and Computer Science Department have developed and tested a cancellation and detection system that achieves full diversity (no interference) with extremely low decoding complexity. The main idea behind this novel system is based on allowing (as opposed to attempting to avoid) interference and then use uniquely designed precoders that use the channel information to remove the interference, similar to destructive interference of EM waves. (more...)

These inventions are techniques for decoding orthogonal and quasi-orthogonal space-time block codes in an optimum or “maximum likelihood” manner. These techniques provide orders of magnitude reduction in computational complexity when compared to the state of the art. (more...)

On a micro-scale, conventional switching devices using bistable structural elements are well-suited for relays and switches, addressable MEMS-based pixel arrays, tunable optical MEMS filters or microfluidic valves. However, the currently employed approaches all need high voltages applied to reach the threshold value force. A novel approach has been developed by researchers at UCI that address this need for high voltage. (more...)

Operation of axial or radial turbines under wet conditions is generally avoided because of three performance disadvantages: (1) droplets are unlikely to strike the turbine blades in a way that efficiently converts their momentum to rotor torque; (2) the liquid film that forms on the turbine blades alters the aerodynamics of the flow and makes it challenging to optimize the design for performance; and (3) droplet impingement in conventional turbines can cause the rotor blades to erode, and thereby shorten the life of the turbine. To address this problem, UC Berkeley researchers have developed a turbine design that is optimized for wet operation (i.e. operation with internal flow of liquid and vapor fluid phases). As the replacement for the expansion valve in vapor compression refrigeration and air-conditioning systems, this innovation can significantly enhance the energy efficiency of vapor compression systems by extracting additional power output and increasing the heat absorbing capacity of the refrigerant in the evaporator. Another version of the innovation can be used as the work output turbine in a Rankine cycle power generation system designed for wet turbine operation. This wet expansion cycle design has significantly higher heat input heat exchanger effectiveness, and higher energy efficiency than conventional Rankine cycles with superheat.  (more...)

Researchers at the University of California, Davis have developed novel core-shell architecture nanoparticles that consist of a gold shell and a phosphor core. These particles are developed using a simple, robust one pot water based technique to coat gold on rare-earth fluoride containing nanometer sized phosphors. The uncoated phosphors are white, while the gold coated phosphors have distinct reddish tints that arise from the surface plasmon resonance of the gold shell. The tunable visible color together with the phosphor emission offers numerous possible applications. (more...)

Current endovascular procedures for the treatment of vascular diseases use a number of metallic devices including guidewires, stents and coils. A popular material for these metallic devices is NiTi and CoCr. Although this material is commonly used, it has several limitations. First, the device generates friction during the installation procedure as the device rubs against the plastic catheter used during installation. A second problem is that once a metal device is placed in an artery, the patient needs to be on blood thinning medications for a long time. This problem can be mitigated by covering the device with native tissues and cells. (more...)

Stiction (adhesion of suspended structures and the underlying surface) is a considerable problem for batch fabricated MEMS devices. MEMS devices are often released through wet etching. As the wafer is removed from the wet etch, liquid is trapped between the small space separating the MEMS device and the substrate. This liquid, through capillary forces, pulls the cantilevered MEMS device down to the substrate where it remains. Numerous techniques have been explored to resolve this problem. However, most require significant trade-offs e.g. non-standard silicon processing, additional design structures, long release process times, etc. (more...)

Bottom-up synthesis can produce a very limited variety of particle shapes, such as spheres and rods, in a viscous liquid. The resulting particles can be highly uniform in size. However, there is no general method for mass-producing a wide variety of highly complex shapes that are specified by a customer using bottom-up self-assembly approaches. Although uniform microspheres have been used extensively in many protocols, these applications can be enhanced by using particles that have customized, user-specified shapes. Mass-producing particle shapes that conform with a desired design would revolutionize the variety of dispersions that are commercially available. (more...)

Ion beams for manufacturing and analytical applications (e.g.; ion beam milling, focused ion beam micromachining, and 3-D profiling of organic samples via secondary ion mass spectrometry) (more...)

Solar concentrators used for heating a working gas or fluid have serious trade-offs in terms of the concentration factor attainable (high light concentrations being desirable for achieving high temperatures and, in power generation applications, high thermodynamic efficiencies) versus the cost of mounting and moving relatively large reflective or refractive surfaces and their associated light-absorbing elements in order to track the Sun's movements across the sky. (more...)

University researchers have designed a family of new dual mass and quadruple mass tuning fork architectures addressing the limitations of the conventional designs. In the dual mass design, the spurious in-phase drive-mode is shifted above the operational frequency to improve the response characteristics. (more...)

University researchers have designed topologies and control schemes that further simplify three-phase rectification circuits, demonstrating that the unified three-phase constant vector controller can be decoupled into two single-phase PFC controllers for two special groups of topologies. Therefore, the design of a three-phase PFC is dramatically simplified, furthermore all techniques and experiences used in single-phase PFC rectifier can be easily adopted by three-phase applications. (more...)

In order to overcome fundamental energy efficiency limits of CMOS technology, micro-electro-mechanical (MEM) relay technologies are now being investigated for ultra-low-power digital integrated circuit (IC) applications. High relay endurance (exceeding 10^14 ON/OFF switching cycles) is required for relay-based ICs to be viable, and has been a major challenge due to stiction and wear. Researchers at UC Berkeley have developed an efficient way to reduce contacts aging, stiction, and oxidation. The researchers have shown that contacts can be made to be very reliable with very low resistance. To date, a contact resistance of 85.2 kohms has been measured at room temperature and suggests the possible use of these contacts for relay-based integrated circuits, which typically requires contact resistances less than 100 kohms. Further work will include coating optimization, surface roughness analysis, dynamic measurements for contact aging evaluation, thermal analysis, extraction of the effective contact area, and advanced current transport modeling. (more...)

University researchers have invented a distributed-mass micromachined gyroscope which minimizes quadrature error, eliminates effects of directional residual stresses, and completely decouples the drive and sense modes. The device has multiple drive-mode oscillators, distributed symmetrically around the center of a supporting frame. The multi-directional linear drive-mode and the rotational sense-mode allows complete decoupling of the drive and sense direction oscillations, minimizing instability and zero-rate drift due to dynamical coupling between the drive and sense modes. Due to the radial symmetry, the drive forces applied to the drive-mode oscillators cancel out in all directions, and the quadrature error is effectively nullified. The effects of directional residual stresses are also eliminated, due to the multi-directional and symmetric nature of the drive-mode oscillators. The device also provides a wide-bandwidth operation region in the drive-mode frequency response. By designing each drive-mode oscillator to have incrementally spaced resonance frequencies, the total Coriolis torque is set at a constant value over a wide range of driving frequency. If the sense-mode resonance frequency is designed to be accommodated in the same frequency band, robustness and insensitivity to parameter fluctuations is achieved. (more...)

Standard electrical motors when used in magnetic resonance (MR) instrumentation may interfere with the functionality of the MR imaging. These interferences from the motor distort the resulting MR images. Developing a motor that operates in high magnetic fields used in MR imaging and MR based intervention procedures without distorting the resulting images is desirable. (more...)

Using novel feedback sensing techniques and a control algorithm (together referred to as "the control system"), researchers at the University of California, Berkeley, have expanded the bandwidth of a professional grade low-frequency transducer, while simultaneously reducing the distortion. The unique idea is that the control system is physically independent of the loudspeaker, allowing the introduction of this technology both as next generation and in combination with existing subwoofers. For an 18-inch professional grade subwoofer, the control system produced a significant improvement in the sub-bass Sound Pressure Level (SPL) response, and reduced harmonic distortion over the controlled region for output levels reaching 140 dB SPL (re 20 ?Pa, 1.25" from the speaker). This was especially evident at lower frequencies where the Total Harmonic Distortion (THD) was reduced by a factor of 0.55 (from 7.0% for the stock system to 3.9% for the closed-loop system). Listening tests consisting of played-back music and test tones using the A/B double blindfold methodology further verified the significant performance enhancements. (more...)

  As the quest for clean, renewable energy intensifies, the proposition of extracting energy from ocean waves sounds increasingly more attractive. The wave energy resource is recognized to contain the highest energy density among renewables and is virtually inexhaustible. Moreover, unlike wind, the wave climate is more predictable and is generally less intermittent. The primary waves of interest are those generated by the blowing of the winds, which in turn are a product of differential heating of the earth. Therefore, the wave energy may be considered as a concentrated form of solar energy. The size (and associated energy) of the resulting waves are a function of wind speed, wind duration, and distance over which the wind blows, referred to as fetch. Original solar power levels of 100 W/m2 can be transformed into waves of power levels of over 1000 kW/m of wave crest length. Researchers at UC Berkeley have developed a new device that applies the principle of parametric excitation to ocean wave energy converters. The proposed mechanism operates fully autonomously when the buoy is heaving. The application leads to greater energy in the oscillatory motion, resulting in increased motion amplitude or, in situations where amplitude limit is reached, the possibility of using higher damping values in the power takeoff system to keep the oscillations bounded. In either case, when power take off is achieved with hydraulic damping, it would be possible to harness significantly more power from the device, compared to a unit simply excited by the waves.   (more...)

Researchers at the University of California, Berkeley have developed an improved method of minimizing the operator force necessary to move a heavy load suspended from an overhead crane. (more...)