Energy storage apparatus

A high efficiency, flywheel type energy storage device which comprises an electronically commutated d.c. motor/generator unit having a massive flywheel rotor magnetically suspended around a ring shaped stator is presented. During periods of low energy demand, the storage devices were operated as a motor, and the flywheel motor was brought up to operating speed. Energy was drawn from the device functioning as a generator as the flywheel rotor rotated during high energy demand periods

Mechanical capacitor

A new energy storage system (the mechanical capacitor), using a spokeless magnetically levitated composite ring rotor, is described and design formulas for sizing the components are presented. This new system is configured around a permanent magnet (flux biased) suspension which has active servo control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of the stationary armature coils is proposed. There is no mechanical contact with the rotating spokeless ring; therefore, long life and near zero rundown losses are projected. A 7-kW h system is sized to demonstrate feasibility. A literature review of flywheel energy storage systems is also presented and general formulas are developed for comparing rotor geometries

Testing of an improved ultrasound flowmeter: technical description and results of testing in vitro

In vitro testing was carried out of an advanced model of an intravascular flowgauge based on the ultrasound principle - that is, measurement of the difference in transit time of an upstream and downstream ultrasound pulse. The gauge was tested extensively to determine its sensitivity and stability as well as the influence of changes of haematocrit and temperature on its performanc

Fe-doping-induced evolution of charge-orbital ordering in a bicritical-state manganite

Impurity effects on the stability of a ferromagnetic metallic state in a bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of metal-insulator transition have been investigated by substituting a variety of transition-metal atoms for Mn ones. Among them, Fe doping exhibits the exceptional ability to dramatically decrease the ferromagnetic transition temperature. Systematic studies on the magnetotransport properties and x-ray diffraction for the Fe-doped crystals have revealed that charge-orbital ordering evolves down to low temperatures, which strongly suppresses the ferromagnetic metallic state. The observed glassy magnetic and transport properties as well as diffuse phase transition can be attributed to the phase-separated state where short-range charge-orbital-ordered clusters are embedded in the ferromagnetic metallic matrix. Such a behavior in the Fe-doped manganites form a marked contrast to the Cr-doping effects on charge-orbital-ordered manganites known as impurity-induced collapse of charge-orbital ordering.Comment: 8 pages, 7 figure

Electro-hydrodynamics of binary electrolytes driven by modulated surface potentials

We study the electro-hydrodynamics of the Debye screening layer that arises in an aqueous binary solution near a planar insulating wall when applying a spatially modulated AC-voltage. Combining this with first order perturbation theory we establish the governing equations for the full non-equilibrium problem and obtain analytic solutions in the bulk for the pressure and velocity fields of the electrolyte and for the electric potential. We find good agreement between the numerics of the full problem and the analytics of the linear theory. Our work provides the theoretical foundations of circuit models discussed in the literature. The non-equilibrium approach also reveals unexpected high-frequency dynamics not predicted by circuit models.Comment: 9 pages including 4 figures. Accepted for PRE

Pulsatile velocity of blood in the pulmonary artery of dogs: measurement by an ultrasound gauge

An advanced model of an ultrasound flow gauge, mounted on a N7 catheter was used to measure flow velocity in the pulmonary artery of closed-chest dogs. The recorded flow signals were calibrated in cm/sec by determining stroke volume (by dye dilution) and diameter of the pulmonary artery (by angiography). The influence of positive and negative inotropic drugs on velocity and acceleration is reporte

Low Power Magnetic Bearing Design for High Speed Rotating Machinery

Magnetic suspension technology has advanced to the point of being able to offer a number of advantages to a variety of applications in the rotating machinery and aerospace fields. One strong advantage is the decrease in power consumption. The design and construction of a set of permanent magnet biased, actively controlled magnetic bearing for a flexible rotor are presented. Both permanent magnets and electromagnets are used in a configuration which effectively provides the necessary fluxes in the appropriate air gaps, while simultaneously keeping the undesirable destabilizing forces to a minimum. The design includes two radial bearings and a thrust bearing. The theoretical development behind the design is briefly discussed. Experimental performance results for a set of operating prototype bearings is presented. The results include measurements of load capacity, bearing stiffness and damping, and the dynamic response of the rotor. With few exceptions, the experimental results matched very well with the predicted performance. The power consumption of these bearings was found to be significantly reduced from that for a comparable set of all electromagnetic bearings

Low Temperature Performance of Bio-Derived/Chemical Additives in Warm Mix Asphalt

Corn and soy based bio-derived warm mix asphalt (WMA) additives are currently being developed. In the past, additives with similar properties have been shown to successfully reduce the mixing and compaction temperatures of asphalt by as much as 30°C. Isosorbide distillation bottoms (IDB), a WMA additive, is a co-product from the conversion of sorbitol to isosorbide, where sorbitol is derived by hydrogenating glucose from corn biomass. Past research utilizing IDB at several dosage rates showed there was improvement in low temperature binder performance using the bending beam rheometer (BBR) between dosage rates of 0.5% and 1.0% by weight of the binder. This research investigates whether low temperature improvement occurs with several new bio-derived material additives that have similar properties to materials used in past research, as well as compares their performance to two commercially available/bio-derived WMA additives from the forest products industry. In cold regions of the United States, the main observed distress in asphalt pavements is low temperature cracking. Characterization of binder performance at low temperature is possible with the use of the BBR. For asphalt mixtures, characterization is more challenging at low temperatures due to the response from the aggregate phase of a mixture. To examine low temperature performance of hot mix asphalt (HMA) and WMA, the semi-circular bend (SCB) test was used to characterize the fracture properties. SCB tests showed that additive choice was a statistically significant factor in fracture energy properties but not for stiffness and fracture toughness. All of the new additives were successfully used at reduced mixing and compaction temperatures and did not adversely impact low temperature mix fracture properties of WMA when compared against the control HMA. However, improvement of fracture energy was observed when comparing the epoxidized esterified fatty acid additive to the other five additives used in this work