Production Research in China

(First paragraph) China is the world’s largest emerging economy. In recent years, China has moved to an increasingly market-oriented economy that opens to international trade and investment. At the same time, the popularity of China as a manufacturing base, assembling goods for sale worldwide is growing. In addition to global manufacturers who have built their own plants in China, many manufacturing companies are outsourcing production to Chinese subcontractors and branding the products with their own logos. In today’s China, production research is becoming more and more important; advanced production research becomes an important enabler to make its manufacturing industry competitive. Although China has different financial, legal, and physical infrastructure, production researchers in China have successfully proven that production research can help to manage global manufacturing competition

Efficient computation and neural processing of astrometric images

In this paper we show that in some peculiar cases, here the generation of astronomical images used for high precision astrometric measurements, an optimised implementation of the DFT algorithm can be more efficient than FFT. The application considered requires generation of large sets of data for the training and test sets needed for neural network estimation and removal of a systematic error called chromaticity. Also, the problem requires a convenient choice of image encoding parameters; in our case, the one-dimensional lowest order moments proved to be an adequate solution. These parameters are then used as inputs to a feed forward neural network, trained by backpropagation, to remove chromaticity

Photocatalysis for Reductive Transformation of Nitrate and Chromate in Drinking Water

abstract: Contamination of drinking water supplies from oxo-anion pollutants necessitates treatment prior to potable use. This dissertation aims to inform and improve light delivery (emission spectra, radiant intensity, reactor configuration) in order to enhance the photocatalytic reduction of hexavalent chromium (Cr(VI)) and nitrate, two common oxo-anions in drinking water, and photocatalytic oxidation of two model organic pollutants (methylene blue, (MB) and para-chlorobenzoic acid (pCBA)). By varying the photon fluence dose, two metrics (contaminant quantum yield (Φ), and electrical energy per order (EEO)) were used to assess photocatalytic reactor performance. A detailed literature review and experimental results demonstrated how different irradiance sources with variable intensity and emission spectra synergistically enhanced contaminant removal by a coupled photolytic/photocatalytic reaction mechanism. Cr(VI) was photocatalytically reduced on TiO2 and formed Cr(OH)3(s) in a large-scale slurry reactor, but Cr(III) was then photolyzed and reformed Cr(VI). UV light also led to photo-aggregation of TiO2 which improved its recovery by the ceramic membrane within the reactor. For nitrate reduction, light source emission spectra and fluence dose delineate the preferred pathways as intermediates were reduced via wavelength-dependent mechanisms. HONO was identified as a key nitrate reduction intermediate, which was reduced photocatalytically (UV wavelengths) and/or readily photolyzed at 365nm, to yield nitrogen gases. Photocatalytic nitrate reduction efficiency was higher for discrete wavelength irradiation than polychromatic irradiation. Light delivery through aqueous media to the catalyst surface limits efficiency of slurry-based photocatalysts because absorption and scattering of light in nanomaterial slurries decreases effective photon transmittance and minimizes photolytic reactions. The use of optical fibers coupled to light emitting diodes (OF-LED) with immobilized catalyst demonstrated higher performance compared to slurry systems. OF-LED increased Φ for MB degradation by increasing direct photon delivery to the photocatalyst. Design of OF-LED reactors using bundled optical fibers demonstrated photocatalytic pCBA removal with high Φ and reduced EEO due to increased surface area and catalytic sites compared to single OF/LED couples. This work advances light delivery as well as the suspension and attachment of nanoparticles in photocatalytic water treatment for selective transformation of oxo-anions and organic compounds to innocuous species.Dissertation/ThesisDoctoral Dissertation Civil, Environmental and Sustainable Engineering 201

Design and Model Verification of an Infrared Chromotomographic Imaging System

A prism chromotomographic hyperspectral imaging sensor is being developed to aid in the study of bomb phenomenology. Reliable chromotomographic reconstruction depends on accurate knowledge of the sensor specific point spread function over all wavelengths of interest. The purpose of this research is to generate the required point spread functions using wave optics techniques and a phase screen model of system aberrations. Phase screens are generated using the Richardson-Lucy algorithm for extracting point spread functions and Gerchberg-Saxton algorithm for phase retrieval. These phase screens are verified by comparing the modeled results of a blackbody source with measurements made using a chromotomographic sensor. The sensor itself is constructed as part of this research. Comparison between the measured and simulated results is based upon the noise statistics of the measured image. Four comparisons between measured and modeled data, each made at a different prism rotation angle, provide the basis for the conclusions of this research. Based on these results, the phase screen technique appears to be valid so long as constraints are placed on the field of view and spectral region over which the screens are applied