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Emergence of increasingly smaller electromechanical systems with submilli-Watt power consumption led to the development of scalable micropower generators (MPGs) that harness ambient energy to provide electrical power on a very small scale. A flow MPG is one particular type which converts the momentum of an incident flow into electrical output. Traditionally, flow energy is harnessed using rotary-type generators whose performance has been shown to drop as their size decreases. To overcome this issue, oscillating flow MPGs were proposed. Unlike rotary-type generators which rely upon a constant aerodynamic force to produce a deflection or rotation, oscillating flow MPGs take advantage of cross-flow instabilities to provide a periodic forcing which can be used to transform the momentum of the moving fluid into mechanical motion. The mechanical motion is then transformed into electricity using an electromechanical transduction element. The purpose of this review article is to summarize important research carried out during the past decade on flow micropower generation using cross-flow instabilities. The summarized research is categorized according to the different instabilities used to excite mechanical motion: galloping, flutter, vortex shedding, and wake-galloping. Under each category, the fundamental mechanism responsible for the instability is explained, and the basic mathematical equations governing the motion of the generator are presented. The main design parameters affecting the performance of the generator are identified, and the pros and cons of each method are highlighted. Possible directions of future research which could help to improve the efficacy of flow MPGs are also discussed.

We developed an integrated chip for real-time amplification and detection of nucleic acid using pH-sensing complementary metal-oxide semiconductor (CMOS) technology. Here we show an amplification-coupled detection method for directly measuring released hydrogen ions during nucleotide incorporation rather than relying on indirect measurements such as fluorescent dyes. This is a label-free, non-optical, real-time method for detecting and quantifying target sequences by monitoring pH signatures of native amplification chemistries. The chip has ion-sensitive field effect transistor (ISFET) sensors, temperature sensors, resistive heating, signal processing and control circuitry all integrated to create a full system-on-chip platform. We evaluated the platform using two amplification strategies: PCR and isothermal amplification. Using this platform, we genotyped and discriminated unique single-nucleotide polymorphism (SNP) variants of the cytochrome P450 family from crude human saliva. We anticipate this semiconductor technology will enable the creation of devices for cost-effective, portable and scalable real-time nucleic acid analysis.

Analatom, Inc. is developing the Structural Health Monitoring (SHM) system using its Linear Polarization Resistance (LPR) corrosion sensors combined with a Texas Instruments MSP430 microprocessor for lower weight, lower power, higher sensitivity, and lower cost than conventional sensor systems. The system provides both strain and corrosion measurements in a package a few mils thick. This combination of data provides critical assessment of structural health, leading to prediction of failure. The MEMS sensors are permanently installed in a highvalued structure, such as a building, bridge or aircraft, and are connected to a data acquisition node. Data transmission and downloading uses a MaxStream ZigBee/IEEE 802.15.4 compliant chip for a wireless, self-organizing network that has low power requirements. The sensor network provides a low-cost, non-intrusive way to detect failures, or to signal ahead of time that preventative maintenance needs to be undertaken to prevent future more expensive replacement. Analatom, Inc. has developed the basic technology for a Portable Maintenance Support Tool (PMST). The device is unique and novel in that it uses a Micro Controller Unit in a handheld device to perform data analysis whilst maintaining a link with a Personal Computer based database for further support. The handheld prototype with a Liquid Crystal Display (LED) touch screen GUI takes readings from a variety of sensors and transfers the data wirelessly to a central PC hub. The handheld unit using the downloaded data from the sensor network can then provide a graphic display and additionally transfer those data to a workstation for further data analysis. Analatom, Inc. builds on its corrosion system platform (sensors, data acquisition unit, data storage) to develop a multiplexed system to obtain data from a variety of sensors, while further developing real time intelligent algorithms to monitor corrosion rates.

Converting park-and-ride to bike-and-ride trips could yield important environmental, energy conservation, and public-health benefits. While cycling in general is becoming increasingly popular in the United States, it still makes up a miniscule portion of access trips to most rail transit stations. At several rail stations of the Bay Area Rapid Transit (BART) system, 10 percent or more of access trips are by bicycle, up considerably from a decade earlier.  This paper adopts a case-study approach to probe factors that have had a hand in not only cycling grabbing a larger market share of access trips to rail stops but also in the enlargement of bike access-sheds over time.  Both on-site factors, like increases the number of secure and protected bicycle parking racks, as well as off-site factors, like increases in the lineal miles of bike-paths and bike boulevards, appear to explain growing use of bicycles for accessing rail stations. The adage “build it and they will come†, we argue, holds for bicycle improvements every bit as much as other forms of urban transportation infrastructure. Pro-active partnerships between transit agencies, local municipalities, and bicycle advocacy organizations are critical to ensuring such improvements are made.Â