213 research outputs found

    Optimal Unknown Bit Filtering for Test Response Masking

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    [[abstract]]In this paper presents a new X-Masking scheme for response compaction. It filters all X states from test response that can no unknown value input to response compactor. In the experimental results, this scheme increased less control data and maintain same observability.[[conferencedate]]20121104~20121107[[iscallforpapers]]Y[[conferencelocation]]New Taipei, Taiwa

    Development of a Semicircular Bend (SCB) Test Method for Performance Testing of Nebraska Asphalt Mixtures

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    X-Codes: Theory and Applications of Unknowable Inputs

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    Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNSF / ACI-99-84492-CAREE

    Assessment of Carbon Emissions of Road Projects and Development of a Framework for Carbon Footprint Calculation of Roads in the City Of Abu Dhabi

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    Climate change has become a global issue affecting the environment and human health. Transportation is a major contributor of greenhouse gases (GHG) emissions, with road transport being responsible for more than half of these emissions. The main objective of this thesis was to estimate the carbon footprint associated with road projects in the city of Abu Dhabi following a comprehensive approach that considers all activities within the life cycle of roads. Three cases were considered including, Al Rahba City internal road network, the upgrading of Al Salam Street, and the widening of the Eastern Corniche Road. A carbon footprint estimation model (referred to as RoadCOâ‚‚) was developed to estimate GHG emissions of the three road cases. The model considers emissions from all phases of road projects and reports emissions in terms of carbon dioxide equivalent (COâ‚‚eq). The methodology suggested by the Intergovernmental Panel on Climate Change (IPCC) was adopted in constructing the model. Results revealed that the total emissions from the construction of the investigated road cases are about 43, 292, and 16 thousand tons COâ‚‚eq, respectively. Equipment used in construction contributed about 70%, 15% and 21% of the total emissions of the construction phase, respectively. The rest of the emissions during the construction phase originated from the use of construction materials and their associated transport. Upgrading of Al Salam Street project produced the highest emissions from construction materials due to the construction of a tunnel. Annual total emissions during the operation phase of Al Salam Street was estimated to be over 108 thousand tons COâ‚‚eq/yr, whereas emissions during the operation phase for Al Rahba City internal roads were about 15 thousand tons COâ‚‚eq/yr, and those for the Corniche Road were 91 thousand tons COâ‚‚eq/yr. For the three cases, emissions were generated mainly during the operation phase (94% or more), with the main contributor being vehicle movement, followed to a lesser extent by street lighting

    Roller Compaction of Pharmaceutical Ingredients : on the Undrestanding of the Compaction and the Use of Knowledge based Applications in the Formulation of Tablets

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    Roller compaction is a dry granulation process which is still not well understood since a large number of processing variables and inherent material attributes make the description of the mechanisms involved in the process extremely complicated. Neither the intermediary compact (i.e., the ribbon) nor the final product (i.e., the granule) is normally used as dosage form. Thus, the granule is usually processed for the production of tablets. When the substance needs to be dry-granulated prior to the tablet production, not only the initial composition of the formulation, but also the processing conditions (device parameters, intermediary steps, etc.), affect the workability of the granule and, consequently, the characteristics of the produced tablets. Thus, the development of a formulation and the optimization of the production process are necessary to meet the mandatory tablet requirements that warrant the pharmaco-therapeutic success of the drug. Expert Systems (ES) are tools that result from combining experience and computing. They can simplify the task of development of new formulations in an accurate, efficient and rapid way by processing, extracting and putting to anyone’s disposal data contained in their data base. This work pretends to join the effort of others on the characterisation of the compaction. The experiments described here supply key hints for the understanding of the process and the variability in the product attributes due to composition of the formulation and processing conditions. Finally, the information and the predictive models created during the experiments have been implemented in the development of an ES in order to demonstrate the benefits of these applications in formulation research. For that purpose, this work reports experiments that analyze the compact process visually and use a critical attribute of the ribbon, the solid fraction, to evidence the interactions between the powder and the rollers, and to describe the effect of the lubrication and other compaction conditions over the dynamics and the densification of the material between the rollers. Moreover, the suitability of a number of techniques for the characterisation of the ribbon solid fraction is analyzed and compared. Furthermore, after close examination of the ribbon quality and also of the granule and the tablets produced from different pharmaceutical substances it has been shown that these product characteristics are strongly affected by the initial composition and by the parameters and the conditions of the process. Moreover, predictive models based on computer general mathematic regressions and artificial neural networks, have been developed using gathered experimental data. The models identify satisfactorily the underlying relationships between the independent variables (composition and process parameters) and the product characteristics, and deliver prognoses of the properties of the intermediary (ribbons and granules) and the final products (tablets). Finally the models are integrated into an ES that has shown to be a user-friendly application that manages the information and retrieves the models to generate a report that includes predictions of the product attributes and helpful information to be born in mind during the production. ESs are extremely useful tools, especially for the pharmaceutical industry, as they ease the formulation development, reducing effort and expenditures, and increasing the consistency, the quality and the efficiency of the formulation tasks. In addition they ensure the permanency and the accessibility of the knowledge and assist the work of both experienced and novice formulators

    A life cycle based energy and greenhouse gas emission assessment of C&D waste and container glass recycling in the City of Cape Town

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    Includes abstract.Includes bibliographical references.The rate at which the world is consuming energy is growing, and with climate change an immediate concern (Stern, 2006), it is incumbent for the global society to find alternate ways of fuelling human activity. Along with greater energy use, global development is also generating ever-greater quantities of waste. Landfill space is becoming increasingly scarce and the assimilative capacity of Earth is reaching its limits. Society's current approach to the production, consumption, and disposal of goods is likely unsustainable. The goal of this research was to assess the difference in cumulative energy demand (CED) and greenhouse gas (GHG) emissions for two waste management options: landfilling and recycling for the two materials of Construction and Demolition (C&D) rubble and container glass in the City of Cape Town (CCT) in order to determine which option has the lower climate impact

    Circular economy design visioning: exploring industrial and urban symbiosis in South African cities.

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    Doctoral Degree. University of KwaZulu-Natal, Durban.Cities of tomorrow will be at the coalface of the complex challenges posed by climate change, e.g. resource scarcity. Climate change adaptation strategies will include circular economy (CE) practices (e.g. industrial and urban symbiosis) to increase the rate of recycling technical nutrients, in turn improving the resource efficiency of cities. The study investigates industrial and urban symbiosis in South Africa. In doing so, exploring technology enabled (i.e. cyber-physical-social ecosystems) CE solutions to designing out waste in South African cities. One of the key contributions of the research is the comprehensive synthesis and testing of an iterative problem structuring, theory building and design visioning (problem-theory-design) continuum to inform CE experimentation. A mixed methods design visioning approach is developed through an experiential and iterative design practice nested in a network of interdisciplinary theoretical constructs: 1) philosophical construct – Ecological Literacy (systems thinking), 2) techno-economic construct – Third Industrial Revolution (internet-of-things enabled general purpose technology platform), and Circular Economy (industrial and urban symbiosis), and 3) design construct – properties of Ecodesign derived from the dynamic renewable design of natural ecosystems. The research argues that to construct a meaningful CE transition experiment, a logical starting point is to distil key findings from a theoretically embedded case study to inform the design of a virtual experiment and simulation sketch. Through an embedded multiple case study approach the research investigates complex resource recovery dynamics in two key waste economy sub-sectors; industrial waste management and urban informal recycling sectors in the province of KwaZulu-Natal (KZN). The case studies provide an integrated method (i.e. synthesising quantitative and qualitative knowledge) for holistic and high-resolution problem structuring. From a systems thinking perspective, key leverage points (i.e. data, information sharing and infrastructure) are identified for potential policy and technology intervention. Learnings from the case studies inform policy recommendations and CE innovation. The findings from the industrial symbiosis (IS) case study illustrate that firms and supply chain networks recognise the environmental importance of improving industrial waste management practices, however they are locked-in to end-of-pipe solutions. Firms highlighted regulation, price sensitivity, customer pressure and top management as key drivers of pro-environmental behaviour change (e.g. waste beneficiation). The findings highlight the unrealised IS potential in the South vi Durban Basin. In addition, revealing significant barriers to IS, i.e. lack of information sharing between firms and a weak regulatory environment. To increase the detection, matching and emergence of IS relationships will command the dynamic co-production of codified resource flow data; herein a big data analytics approach can be employed to construct open source platforms for interfirm information (e.g. residual resource flows) sharing and knowledge production – an industrial commons internet. The urban symbiosis case study explores the informal recycling sector in KZN analysing the instrumental role of waste pickers as primary looping agents in recovering recyclable materials from post-consumer waste and increasing the supply of recyclable materials (e.g. cardboard, paper, plastic and metal) in the secondary resources economy. Waste pickers are an important link in recycling value chains; sorting, gathering and manually transporting recyclable materials to buy-back-centres and informal collection pick up points. The case study investigates how their efficiency can be improved to stimulate greater positive environmental impacts, create decent employment opportunities, and reduce waste management costs for municipalities. The findings from the case study on waste pickers are extrapolated in a CE design visioning exercise. From a systems level perspective, the research culminates in the sketch of a virtual circular city experiment; a cyber-physical social ecosystem (CPSE) designed to increase recycling rates in cities by addressing the infrastructural needs of waste pickers. The hardware, software and social ecosystem is built out of an internet-of-things (IoT) platform. Firstly, the IoT enabled infrastructural system improves material recovery efficiencies (of post-consumer recyclable materials) by increasing connectivity between waste pickers and waste collectors. Increased connectivity allows for looping and aggregating material stock and flow data. Secondly, the integrated hardware and software infrastructure provides an automated, digitised and decentralised buy-back-transfer service – delivered through connected and solar-powered collection nodes strategically distributed throughout the city in a mesh network configuration. Thirdly, the digital platform aggregates big data and employs advanced analytics to generate actionable residual resource intelligence, consequently enabling evidence-based decision making by key stakeholders, e.g. government agencies, industry associations, recyclers and material reprocessors. To further the research agenda, the next step is structuring a real-world transition experiment based on the virtual circular city design experiment, defined as, the internet-of-waste pickers (IoWP)

    Characterisation of Tablets and Roller-Compacted Ribbons with Terahertz Time-Domain Pulsed Imaging

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    The pharmaceutical process of dry granulation using roller-compaction (DG/RC) is effectively a non-batch based procedure orientated to deliver a continuous stream of material free of a pre-defined batch-size with reduced plant equipment/scale-up R&D resources and an enhanced work-throughput, particularly suitable for moisture sensitive formulation. The desirable accreditations of DG/RC are many; yet by the nature of a more flexible approach than (i.e. wet-granulation), it must be highly monitored and controlled to accomplish higher-throughput rates and reduced ‘static’ material testing stages. To monitor rapidly and in-line with production, pre-granulated ribbons of RC (which highly correlates to the post milled granulates), terahertz time-domain spectroscopy (TDS) is used to elucidate the key physical attributes of post-compression density and thickness uniformity, key to end-product consistency. Invariably a great number of conditions apply to DG/RC (viz: System design, material characteristics, environmental and unit configuration), although widely regarded as the key processing parameters (PP’s) are roll-pressure and roll-gap [1-4]. The target of the study is to derive a strategy to position TDS as PAT to DG/RC. Two terahertz time-domain TD methods of a conventional transmission setup and reflection (TPI) THz analysis are used on standards of glass slides for verifying the interpretational foundations of the TD methods. Achieving RI/thickness error-discrepancies +2.2 to -0.4% c.f. literature ([150]) values provides foundations to test the solid-fraction ratios of pharma tablets with regard to RI’s being surrogate values to SF/path-length (R2 = 1). Combining transmission principles to the portion of reflected EMR removes the pre-requisite for RI or path-length knowledge, giving +1.5 to +2.4% RI agreement (vs. frequency-domain attained results) thus enabling thickness estimations to be above 95% against physical micrometre judgement in all models. Augmentation of the TD methods, refined in Experimental chapter 2 ,then chiefly focuses on TPI as the principle THz-TD method (as the most ideal tool for PAT) for adopting the RI measures for ribbon uniformity analysis in Experimental chapter 4 in an off-line environment again resulting in RI and thicknesses < 5 % error of known parameters of thickness and further use of RI as a proxy porosity equivalent to gas pycnometry. Elucidated in the work are the limitations encountered with tablets and RC’s, data interpretation of industrial considerations. Experimental chapter 3 diverges from RI to differentiate thickness in-order to assess the FD transmission for non-destructive mechanical assessment. This demonstrates a clear relationship between compaction force and the surrogate value for density, following a linear trend below a certain threshold of force. The ‘threshold’ value is observed for less massive tablets, and concluded is that the mechanistic interplay and permanent (plastic) consolidation is greater in instances where compaction-force increases proportionally with target-fill weights, and thus the various behaviour of MCC to stress
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