Determining end-of-life policy for recoverable products

We address a problem that arises for an original equipment manufacturer (OEM) who produces a product both in new and remanufactured forms. A remanufactured product is produced using the parts harvested from recovered products (cores) upon their disassembly, and it may contain some new parts while the excess good parts from cores are salvaged for profit. Other options are available to the OEM for handling cores that do not require disassembly. It follows that the per-unit remanufacturing cost is not constant and it may change depending on the number of recovered cores, good-part reclamation yields, and sales of remanufactured products. We present analytical results for determining an optimal solution with regard to: (i) quantity of cores to collect, (ii) end-of-life (EOL) options for the cores and (iii) product pricing of new and remanufactured products. Our analysis reveals existence of a ‘limiting part’ that dictates the number of cores to collect and a ‘key part’ that determines the number of remanufactured products to make as well as the fact that the availability of cores does not impact the EOL policy type for a product. Our analysis also enables mapping of product characteristics onto corresponding EOL policy types.     

A novel robust exclusive-OR function implementation in QCA nanotechnology with energy dissipation analysis

Numerous scientific and fundamental hindrances have resulted in a slow down of silicon technology and opened new possibilities for emerging research devices and structures. The need has arisen to expedite new methods to interface these nanostructures for computing applications. Quantum-dot Cellular Automata (QCA) is one of such computing paradigm and means of encoding binary information. QCA computing offers potential advantages of ultra-low power dissipation, improved speed and highly density structures. This paper presents a novel two-input Exclusive-OR (XOR) gate implementation in quantum-dot cellular automata nanotechnology with minimum area and power dissipation as compared to previous designs. The proposed novel QCA based XOR structure uses only 28 QCA cells with an area of \(0.02\,\upmu \hbox {m}^{2}\) and latency of 0.75 clock cycles. Also the proposed novel XOR gate is implemented in single layer without using any coplanar and multi-layer cross-over wiring facilitating highly robust and dense QCA circuit implementations. To investigate the efficacy of our proposed design in complex array of QCA structures, 4, 8, 16 and 32-bit even parity generator circuits were implemented. The proposed 4-bit even parity design occupies 9 and 50 % less area and has 12.5 and 22.22 % less latency as compared to previous designs. The 32-bit even parity design occupies 22 % less area than the best reported previous design. The proposed novel XOR structure has 28 % less switching energy dissipation, 10 % less average leakage energy dissipation and 19 % less average energy dissipation than best reported design. The simulation results verified that the proposed design offers significant improvements in terms of area, latency, energy dissipation and structural implementation requirements. All designs have been functionally verified in the QCADesigner tool for GaAs/AlGaAs heterostructure based semiconductor implementations. The energy dissipation results have been computed using an accurate QCAPro tool.     

Effect of agitated bed drying on the retention of phenolic compounds,anthocyanins and antioxidant activity of roselle (Hibiscus sabdariffa L.)

An agitated fluidised bed dryer was employed to dry lixiviated roselle (Hibiscus sabdariffa L.) calyxes. The effects of operational drying variables on the chemical attributes such as the retention of monomeric anthocyanins (MA), phenolic compounds, polymeric colour, antioxidant activity and drying rate were analysed. Drying curves showed only decreasing falling rate period. To determine the kinetic parameters, the drying data were fitted to a Page's model, based on the moisture content ratio vs. the drying time; the k values ranged from 1.58 × 10^?5 to 6.28 × 10^?2 s^?1. The different drying conditions showed significant differences in the chemical parameters. When processing wet feeds, as lixiviated roselle calyxes, the mechanical assisted fluidisation can be considered as an innovative concept.     

Beitr?ge zur Kenntnis des russischen Kochsalzes

Ohne Zusammenfassung     

Growth and Characterization of Lu2O3:Eu3+ Thin Films on Single-Crystal Yttria-Doped Zirconia

Lu₂O₃ doped with Eu³⁺ has been established as an excellent scintillator material for numerous applications such as lasers, optical lenses, and radiography. The material is typically manufactured via hot pressing. This process, apart from being prohibitively expensive, can also introduce major structural defects because it requires grinding/polishing to achieve high transparency and spatial resolution. To overcome these process limitations that have restricted the commercial viability of Lu₂O₃:Eu³⁺ scintillators, a technique to deposit thin films (1–10 μm) of Lu₂O₃:Eu³⁺ has been developed. This investigation characterized the growth of such thin films by radio frequency (RF) magnetron sputtering on single-crystal cubic yttria doped zirconia (YSZ) substrates. At a deposition rate of 3.3 Å/s, the effects of substrate heating and orientation on coating structure property and the resultant effect on performance were evaluated. Additionally, the effect of deposition parameters and growth conditions on the radioluminescence of the coatings, excited by x-rays, was systematically examined.     

Iron Corrosion Scales: Model for Scale Growth, Iron Release, and Colored Water Formation

This paper was presented in part by V. L. Snoeyink as the Simon W. Freese Lecture at the 2002 Canadian Society of Civil Engineers/Environmental and Water Resources Institute of ASCE Environmental Engineering Conference in Niagara Falls, Ontario, Canada, July 22, 2002. The interactions of corroded iron pipe surfaces with water are of importance because they can lead to serious water quality degradation and material deterioration. A conceptual model has been developed in this paper to describe the formation and growth of iron scales, and their reactions that lead to colored water problems. Most corrosion scales have characteristic structural features, such as a loosely held top surface layer, a shell-like layer(s), and a porous core. According to this model corrosion scales are expected to grow from inside the scale via the corrosion reaction, i.e., the conversion of iron metal to ferrous ion. The average oxidation state of iron increases with distance from the pipe wall. The scale structure and scale reactions permit the ferrous iron to be released to the bulk water, where it undergoes conversion to particulate ferric iron, which is the cause of colored water. Scale structure and composition play important roles in the reactions of iron scales that lead to iron release, and water quality control to decrease the porosity of the scale is an important means of reducing iron release. It is anticipated that the conceptual model presented here will be used as a basis for changing water quality to minimize colored water formation, and as a guide for further research.     

Two-dimensional CRC for efficient transmission of ATM cells overCDMA

An integrated system for code-division multiple access (CDMA) radio access to the asynchronous transfer mode (ATM) network is considered. The inherently high error rate associated with the Rayleigh fading channel is overcome by two-dimensional CRC codes for efficient ATM-CDMA interfacing. Simulations show promising error probability performance with low coding redundancy     

Phase Transformations in the High-Temperature Form of Pure and TiO2-Stabilized Ta2O5

The high-temperature forms of undoped tantalum pentoxide (H-100Ta₂O₅) and TiO₂–modified Ta₂O₅ (H-92Ta₂O₅–8TiO₂) were investigated by in situ synchrotron X-ray diffraction and Raman scattering measurements. Two unquenchable and reversible phase transformations were observed in pure H-Ta₂O₅, while only one was detected for TiO₂-stabilized H-Ta₂O₅. Diffraction studies were consistent with displasive transformations, but hot-stage Raman spectroscopy indicated the existence of transient intermediate forms during the transformations. Use of complementary techniques enabled the reinterpretation of phase transformations in light of a newly proposed crystal structure model for H-Ta₂O₅, ¹ and emphasized the structural contributions of the oxygen sublattice.     

A program for dispatching and routing AGVs

This paper describes a program for dispatching and routing of AGVs in real time in a flexible manufacturing environment. The AGVs are assumed to travel on a bidirectional guidepath. Given a set of open jobs, job priorities, their production routings, number of AGVs, AGV travel speeds and their loading/unloading times, the program decides which AGV to dispatch and the path to be followed by the AGV. Continuous monitoring of the system is made possible by a graphical display of AGV movements. The program can also be used to evaluate the design of the AGV system. Some computational results are presented to illustrate this.