The strategic design and development of ERP and RTMS

One of the crucial requirements of global manufacturing strategy is the ability to optimise the use of information technology. This paper describes a process to implement manufacturing strategies that are consistent with a particular company's overall business strategies and results with conceptual system architecture. A methodology is proposed and used to identify and implement an integrated manufacturing strategy which consists of two major horizons: Enterprise Resources Planning (ERP) and a Real-Time Monitoring system (RTMS). RTMS, which can provide up-to-date information for the planning and scheduling of manufacturing orders, monitoring quality, improving communication and increasing productivity, is implemented and is integrated with an ERP system. The architecture of the ERP system is designed for a global manufacturing environment. The implementation was designed with a Distributed Object-Oriented Technology (DOOT) which increases the system scalability, configurability, flexibility and interoperability. The ERP is designed to support real-time data collection and processing for all required production and inventory analysis with a flexible architecture which can meet the distributed business requirements.     

Embedding Pyramids into 3D Meshes

The pyramid architecture is a powerful topology in the area of computer vision. On the other hand, the 3D mesh architecture possesses rich topological features which make it suitable for building scalable parallel processor systems. The usefulness of these two architectures has led us to consider the problem of embedding pyramids into 3D meshes, for which we present two solutions. The first solution, termednatural embedding,maps a pyramid into a 3D mesh such that each level of the pyramid is mapped to a single level of the 3D mesh. The second solution, termedmultiple embedding,allows simultaneous embedding of multiple pyramids into a single 3D mesh. The quality of both solutions is evaluated using dilation and expansion measures. Using the multiple embedding, we are able to obtain an average dilation of 1.26 and a near-optimal expansion of 1.12.     

Ultrasonic spectroscopy study of relaxation and scattering in whey protein solutions

Ultrasonic attenuation spectroscopy was used to investigate the influence of pH on fast chemical reactions and aggregation of whey proteins in aqueous solution. Ultrasonic attenuation spectra (1–100 MHz) of 2.5 wt% aqueous solutions containing either ‘native’ or ‘alkali-denatured’ proteins were measured as a function of pH (2–12). Peaks in the attenuation occurred at pH 2.8 and 11.6 due to proton transfer equilibria, ie  CO₂H ↔  CO₂⁻ + H⁺ and  NH₂ + H⁺ ↔  NH₃⁺ respectively. Attenuation at other pH values was attributed to a hydration relaxation mechanism. Relaxation times for the equilibria were of the order of 10⁻⁸ s. There was an additional attenuation peak at the isoelectric point of the proteins (pH 5) for solutions containing ‘alkali-denatured’ protein, which was due to scattering of ultrasound by aggregated proteins. The particle size distribution of the aggregates could be determined using ultrasonic scattering theory to analyse the attenuation spectra. Ultrasonic spectroscopy is an extremely valuable tool for probing the molecular characteristics of proteins in solution. © 1999 Society of Chemical Industry     

Hybrid passivated colloidal quantum dot solids

Colloidal quantum dot (CQD) films allow large-area solution processing and bandgap tuning through the quantum size effect. However, the high ratio of surface area to volume makes CQD films prone to high trap state densities if surfaces are imperfectly passivated, promoting recombination of charge carriers that is detrimental to device performance. Recent advances have replaced the long insulating ligands that enable colloidal stability following synthesis with shorter organic linkers or halide anions, leading to improved passivation and higher packing densities. Although this substitution has been performed using solid-state ligand exchange, a solution-based approach is preferable because it enables increased control over the balance of charges on the surface of the quantum dot, which is essential for eliminating midgap trap states. Furthermore, the solution-based approach leverages recent progress in metal:chalcogen chemistry in the liquid phase. Here, we quantify the density of midgap trap states in CQD solids and show that the performance of CQD-based photovoltaics is now limited by electron-hole recombination due to these states. Next, using density functional theory and optoelectronic device modelling, we show that to improve this performance it is essential to bind a suitable ligand to each potential trap site on the surface of the quantum dot. We then develop a robust hybrid passivation scheme that involves introducing halide anions during the end stages of the synthesis process, which can passivate trap sites that are inaccessible to much larger organic ligands. An organic crosslinking strategy is then used to form the film. Finally, we use our hybrid passivated CQD solid to fabricate a solar cell with a certified efficiency of 7.0%, which is a record for a CQD photovoltaic device.     

A paradigm for ERP and BPR integration

In order to sustain a competitive edge in this global manufacturing era, enterprises need to adopt appropriate improvement schemes. Two widely-used tools have been Enterprise Resource Planning (ERP) and Business Process Reengineering (BPR). ERP is identified as the most applicable information system for the modern manufacturing industry. In addition, many BPR practitioners have identified the use of information technology (IT) as a critical factor for the success of BPR. Nevertheless, research into IT for BPR and hence ERP is limited. One of the major reasons why the ERP system has not been implemented successfully is the inappropriate use of design and implementation methodology employing the modern BPR concept. Accordingly, in this paper, the authors propose a conceptual model called the Hierarchical Design Pyramid (HDP), to implement ERP under an enterprise re-engineering (BPR) context, using an integrated structured and object-oriented tool to design a novel manufacturing system in a total quality environment. The proposed model aims to provide a basis for manufacturers to implement ERP in a systematic manner.     

Investigation of the reconfigurable control system for an agile manufacturing cell

A new type of manufacturing cell, with characteristics of reconfigurability, reusability and scalability, needs to be developed. To achieve the agile reconfiguration of a manufacturing cell, the cell control system must be rapidly and efficiently generated or modified. In this paper, a multi-agent based architecture is defined that supports the design and implementation of highly reconfigurable control systems for agile manufacturing cells, which are comprised of resource agents (material processing agents, material handling agents, and material storage agents), a control agent, and an information agent, in order to reduce costs and increase the control system's agility with respect to the changing environment. Different agents in the cell control system can be organized dynamically, communicate with each other through messages, and cooperate with each other to perform flexibly the task in the cell control system. The structure of the agents is proposed and the message-passing between agents is discussed in detail.     

Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles: part 2-toxicity and Ag speciation

To study the effects of complex environmental media on silver nanoparticle (AgNP) toxicity, AgNPs were added to microcosms with freshwater sediments and two species of aquatic plants (Potamogeton diversifolius and Egeria densa), followed by toxicity testing with microcosm surface water. Microcosms were designed with four environmental matrices in order to determine the contribution of each environmental compartment to changes in toxicity: water only (W), water + sediment (WS), water + plants (WP), and water + plants + sediment (WPS). Silver treatments included AgNPs with two different coatings, gum arabic (GA-AgNPs) or polyvinylpyrollidone (PVP-AgNPs), as well as AgNO(3). Water samples taken from the microcosms at 24 h postdosing were used in acute toxicity tests with two standard model organisms, early life stage zebrafish (Danio rerio) and Daphnia magna. Speciation of Ag in these samples was analyzed using Ag L3-edge X-ray absorption near edge spectroscopy (XANES). Silver speciation patterns for the nanoparticle treatments varied significantly by coating type. While PVP-AgNPs were quite stable and resisted transformation across all matrices (>92.4% Ag(0)), GA-AgNP speciation patterns suggest significantly higher transformation rates, especially in treatments with plants (<69.2% and <58.8% Ag(0) in WP and WPS, respectively) and moderately increased transformation with sediments (<85.6% Ag(0)). Additionally, the presence of plants in the microcosms (with and without sediments) reduced both the concentration of Ag in the water column and toxicity for all Ag treatments. Reductions in toxicity may have been related to decreased water column concentrations as well as changes in the surface chemistry of the particles induced by organic substances released from the plants.     

Spatial and temporal distribution of singlet oxygen in Lake Superior

A multiyear field study was undertaken on Lake Superior to investigate singlet oxygen ((1)O(2)) photoproduction. Specifically, trends within the lake were examined, along with an assessment of whether correlations existed between chromophoric dissolved organic matter (CDOM) characteristics and (1)O(2) production rates and quantum yields. Quantum yield values were determined and used to estimate noontime surface (1)O(2) steady-state concentrations ([(1)O(2)](ss)). Samples were subdivided into three categories based on their absorbance properties (a300): riverine, river-impacted, or open lake sites. Using calculated surface [(1)O(2)](ss), photochemical half-lives under continuous summer sunlight were calculated for cimetidine, a pharmaceutical whose reaction with (1)O(2) has been established, to be on the order of hours, days, and a week for the riverine, river-impacted, and open lake waters, respectively. Of the CDOM properties investigated, it was found that dissolved organic carbon (DOC) and a300 were the best parameters for predicting production rates of [(1)O(2)](ss). For example, given the correlations found, one could predict [(1)O(2)](ss) within a factor of 4 using a300 alone. Changes in the quantum efficiency of (1)O(2) production upon dilution of river water samples with lake water samples demonstrated that the CDOM found in the open lake is not simply diluted riverine organic matter. The open lake pool was characterized by low absorption coefficient, low fluorescence, and low DOC, but more highly efficient (1)O(2) production and predominates the Lake Superior system spatially. This study establishes that parameters that reflect the quantity of CDOM (e.g., a300 and DOC) correlate with (1)O(2) production rates, while parameters that characterize the absorbance spectrum (e.g., spectral slope coefficient and E2:E3) correlate with (1)O(2) production quantum yields.