Kinetics of the Amorphous →γ→α Transformations in Aluminum Oxide: Effect of Crystallographic Orientation

Time-resolved reflectivity (TRR) measurements have been used to determine the growth kinetics of both the amorphous-to-γ-phase and the γ-to-α phase transformations of alumina films that have been deposited on (0001), (1210), and (0112) sapphire substrates. The activation energies for the amorphous-to-γ-phase and γ-to-α transformations respectively are 4.5 and 5.2 eV, irrespective of the crystallographic orientation of the underlying sapphire substrate. For both transformations, the relative transformation rates seem to reflect the symmetry of the sapphire substrates, with the fastest kinetics being on the lowest symmetry orientation and slowest kinetics being on the highest symmetry orientation. These relative rates are attributed to the differences in step mobility on the different substrate orientations.     

Improved myoelectric prosthesis control using targeted reinnervation surgery: a case series.

Targeted reinnervation is a surgical technique developed to increase the number of myoelectric input sites available to control an upper-limb prosthesis. Because signals from the nerves related to specific movements are used to control those missing degrees-of-freedom, the control of a prosthesis using this procedure is more physiologically appropriate compared to conventional control. This procedure has successfully been performed on three people with a shoulder disarticulation level amputation and three people with a transhumeral level amputation. Performance on timed tests, including the box-and-blocks test and clothespin test, has increased two to six times. Options for new control strategies are discussed.     

Evaluation of a platinum leasing program for fuel cell vehicles

This paper evaluates the feasibility of a platinum leasing program for future fuel-cell vehicles (FCVs) in the United States. By internalizing the residual value of platinum in the vehicle's upfront cost, a platinum lease may offer cost savings to the consumer. Several leasing scenarios were evaluated to estimate potential cash savings.     

Prospects for solar cooling – An economic and environmental assessment

Producing refrigeration and/or air conditioning from solar energy remains an inviting prospect, given that a typical building’s cooling load peaks within 2 or 3 h of the time of maximum solar irradiation. The attractiveness of “free” cooling obtained from the sun has spawned a wealth of research over the last several decades, as summarized in a number of review articles. Obstacles—especially high initial costs—remain to the widespread commercialization of solar cooling technologies. It is not clear at the present time if thermally driven systems will prove to be more competitive than electrically driven systems. We therefore describe a technical and economic comparison of existing solar cooling approaches, including both thermally and electrically driven. We compare the initial costs of each technology, including projections about future costs of solar electric and solar thermal systems. Additionally we include estimates of the environmental impacts of the key components in each solar cooling system presented. One measure of particular importance for social acceptance of solar cooling technologies is the required “footprint,” or collector area, necessary for a given cooling capacity. We conclude with recommendations for future research and development to stimulate broader acceptance of solar cooling. The projections made show that solar electric cooling will require the lowest capital investment in 2030 due to the high COPs of vapor compression refrigeration and strong cost reduction targets for PV technology.     

Detection of subsurface rocks in sand of similar composition using a millimeter wave imaging system

The ability to image objects, whether natural or man made, beneath soil is extremely beneficial. The detection scenario becomes increasingly difficult when the object and the soil are composed of the same material, as in the detection of subsurface rocks. The feasibility of detecting rock in similar composition is explored. An active multi-spectral millimeter wave (mmW) imaging system operating from 90–140 GHz is used to detect lava rock buried beneath lava sand at various depths, up to a limit of 64 mm. The principal component analysis method was used in the data processing.     

Quantum convolutional coding with shared entanglement: general structure

We present a general theory of entanglement-assisted quantum convolutional coding. The codes have a convolutional or memory structure, they assume that the sender and receiver share noiseless entanglement prior to quantum communication, and they are not restricted to possess the Calderbank–Shor–Steane structure as in previous work. We provide two significant advances for quantum convolutional coding theory. We first show how to “expand” a given set of quantum convolutional generators. This expansion step acts as a preprocessor for a polynomial symplectic Gram–Schmidt orthogonalization procedure that simplifies the commutation relations of the expanded generators to be the same as those of entangled Bell states (ebits) and ancilla qubits. The above two steps produce a set of generators with equivalent error-correcting properties to those of the original generators. We then demonstrate how to perform online encoding and decoding for a stream of information qubits, halves of ebits, and ancilla qubits. The upshot of our theory is that the quantum code designer can engineer quantum convolutional codes with desirable error-correcting properties without having to worry about the commutation relations of these generators.     

Economic feasibility of energy efficiency measures in residential buildings

A study has been performed to develop cost benefit data to be used by a local electric utility in defining a rebate program to encourage energy efficient construction in the Desert Southwest region of the USA. Several potential efficiency upgrades for production homes in the region were identified and an evaluation of each building component was performed using building energy simulation software. A model home developed in Las Vegas was used to calibrate the numerical model and was considered as a basis for further study. The validated building models were then used to predict the annual energy savings and payback periods for various upgrades. In all cases, comparisons were made to code-built houses with the same general overall characteristics. Useful life of most of these upgrades far exceeds their payback periods. It is found that a typical house, with the cost-effective upgrades installed, consumed 42.5% less annual energy compared to a home built to code. A 3.19 kWp PV system installed on the south-facing roof of the home can generate 5982 kWh annually, making it a net-zero (electrical) energy home. PV systems in Las Vegas have encouraging benefit cost ratios when federal and state rebates are considered.     

Microstructure and mechanical properties of Al2O3 matrix nanocomposites produced by solid state precipitation

A novel and economical processing route for the production of Al₂O₃-based ceramic nanocomposites via solid solution–precipitation is reported. Dense (>98% ρ_th) and homogeneous solid solutions of 10 wt.% Fe₂O₃ in Al₂O₃ were produced by pressureless sintering at 1450 °C in air. Aging of the solid solutions in a reducing atmosphere at temperatures in the range 1250–1550 °C for different durations (up to 50 h) resulted in the precipitation of FeAl₂O₄ as second phase particles throughout the bulk of the samples. The optimum aging schedule resulted in a final microstructure comprising nano-sized (～100 nm) intragranular FeAl₂O₄ particles, along with coarser micro-sized particles on the matrix grain boundaries and triple point corners. Additionally, surface layers containing metallic Fe and with thicknesses up to ～100 μm were formed due to the further reduction of FeAl₂O₄. After removal of this surface layer, the hybrid nano/microcomposites possessed improved fracture toughness (by ～40%) and flexural strength (by ～50%) with respect to monolithic Al₂O₃.