Showing papers by "Ryerson University published in 1997"
22 Jun 1997
TL;DR: In this article, three new integration algorithms for motor flux estimation are proposed for high-performance sensorless AC motor drives, which can accurately measure the motor flux including its magnitude and phase angle over a wide speed range.
Abstract: Three new integration algorithms for motor flux estimation are proposed in this paper. These algorithms are developed for use in high-performance sensorless AC motor drives. The first algorithm is used to elaborate the basic operating principle. The second one is designed for the drives that require a constant air-gap flux during operation. The third algorithm, in which an adaptive controller is used, can have wide industrial applications. The proposed algorithms can effectively solve the problems associated with pure integrators. These algorithms can be used to accurately measure the motor flux including its magnitude and phase angle over a wide speed range (1:100). The provenance of the algorithms is investigated, compared, and verified experimentally.
557 citations
TL;DR: In this article, the main relationships between energy and environmental impact are identified, including order-destruction/chaos-creation, resource degradation and waste exergy emissions, and some examples are given demonstrating the use of exergy analysis in addressing and solving environmental problems.
Abstract: Environmental problems span a continuously growing range of pollutants, hazards and eco-system degradation factors that affect areas ranging from local through regional to global. Some of these problems may arise from observable, chronic effects on, for instance, human health, while others may stem from the perceived risk of a possible accidental release of hazardous materials. A significant number of these environmental issues are caused by or relate to the production, transformation and end use of energy. In this regard, energy and environment studies which lead to increased energy efficiency can reduce environmental impact by reducing energy losses. Within the scope of exergy methods, such activities lead to increased exergy efficiency, which is of great importance for practical applications. In this study, the main relationships between energy and environmental impact are identified. Historical and modern examples are used to illustrate some of the concepts. The relationships introduced are: order-destruction/chaos-creation, resource degradation and waste exergy emissions. Some examples are given demonstrating the use of exergy analysis in addressing and solving environmental problems. © 1997 by John Wiley & Sons, Ltd.
256 citations
TL;DR: In this paper, the authors investigated the complex structural matrix of riverine flocs over a large range of magnifications using correlative microscopic techniques and found that the floe's internal structure has a significant impact on controlling the above floc behaviours.
Abstract: Flocculated fine-grained sediment is a complex matrix of microbial communities and organic (detritus, cellular debris and extracellular polymers) and inorganic material. Suspended flocs within any aquatic system play a significant ecological role as they can regulate the overall water quality through their physical, chemical and/or biological activity. This paper investigates the complex structural matrix of riverine flocs over a large range of magnifications using correlative microscopic techniques. The significance of floc structural characteristics [(size, shape, porosity, density, inorganic composition, organic composition (bacteria and fibrils)] on the physical (eg. transport and settling), chemical (eg. adsorbing/transforming contaminants and nutrients), and biological (eg. biotransformation and habitat development) behaviour of a floc is investigated. Results suggest that it is the floe’s internal structure that has a significant impact on controlling the above floc behaviours. This internalstructure is complex and is often dominated by the existence of a three-dimensional matrix of fibrillar material secreted by the active microbial community within the floc. This matrix, in conjunction with the inorganic and bioorganic (active and inactive) constituents of a floc, provides an intricate pore structure that may result in water being an important bound component of a floc. These complex interactive structural and functional properties of a floe are considered to influence a floe’s behaviour both physically in how it is transported or settled, chemically in how it adsorbs/transforms contaminants and nutrients, and biologically in how it develops a diverse microhabitat capable of modifying the structural, chemical and biological makeup of the floc.
198 citations
TL;DR: The basic structure of GMCR II and how it works in practice are described, which describes its use to model and analyze an international environmental management dispute that took place in North America.
178 citations
TL;DR: A modeling technique for analyzing sectoral energy use of a country, by considering the flows of energy and exergy through the four major economic sectors (residential/ commercial, industrial, transportation, and utility), is applied to Turkish sectoral EE as mentioned in this paper.
Abstract: A modeling technique for analyzing sectoral energy use of a country, by considering the flows of energy and exergy through the four major economic sectors (residential/ commercial, industrial, transportation, and utility), is applied to Turkish sectoral energy utilization. Energy and exergy efficiencies for the four main sectors of the Turkish economy and for Turkey as a whole are obtained. The results provide insights into Turkish energy use that may assist in energy planning for that country.
140 citations
TL;DR: This paper describes a three-step process of self-reflection encompassing critical appraisal, peer group discussion and self-awareness that was initiated with one group of clinical nursing students.
Abstract: Fiscal and financial constraints present a challenge for nurse educators to broaden the diversity and scope of teaching/learning methodologies. One method designed to promote autonomy and self-direction of nursing students is self-reflection combined with reflective journal writing. This paper describes a three-step process of self-reflection encompassing critical appraisal, peer group discussion and self-awareness. This process of self-reflection was initiated with one group of clinical nursing students. Using student and teacher feedback, implications for employing this teaching/learning strategy in clinical practice are suggested.
137 citations
TL;DR: The 1990s mark an important phase in the evolution of the internationalization of higher education as discussed by the authors and one distinguidshing feature is the different priorities the various stakeholder groups ring to different priorities.
Abstract: The 1990s mark an important phase in the evolution of the internationalization of higher education. One distinguidshing feature is the different priorities the various stakeholder groups ring to th...
99 citations
TL;DR: There appears to be an unusually high degree of substrate specificity with respect to the utilization of abietane congeners and the presence of substituents in relation to the biological treatment of pulp and paper mill effluents.
Abstract: Resin acids, a group of diterpenoid carboxylic acids present mainly in softwood species, are present in many pulp mill effluents and toxic to fish in recipient waters. They are considered to be readily biodegradable. However, their removal across biological treatment systems has been shown to vary. Recent studies indicate that natural resin acids and transformation products may accumulate in sediments and pose acute and chronic toxicity to fish. Several resin acid biotransformation compounds have also been shown to bioaccumulate and to be more resistant to biodegradation than the original material. Until recently, the microbiology of resin-acid degradation has received only scant attention. Although wood-inhabiting fungi have been shown to decrease the level of resin present in wood, there is no conclusive evidence that fungi can completely degrade these compounds. In contrast, a number of bacterial isolates have recently been described which are able to utilize dehydroabietic or isopimaric acids as their sole carbon source. There appears to be an unusually high degree of substrate specificity with respect to the utilization of abietane congeners and the presence of substituents. Pimaranes do not appear to be attacked to the same extent as the abietanes. This paper reviews the occurrence, chemistry, toxicity, and biodegradation of resin acids in relation to the biological treatment of pulp and paper mill effluents.
93 citations
TL;DR: Aggregate results indicate that replacing signals by multiway stop signs on one-way streets is associated with a reduction in crashes of approximately 24%, combining all severities, light conditions, and impact types.
88 citations
TL;DR: The authors argued that regionalism represents one of the most fundamental restructuring processes affecting the world economy since the principles of international trade were established at the Bretton-woods Conference, and argued that multilateralism and regionalism represent competing, but not necessarily mutually exclusive, principles underpinning economic integration and trade in the global economy.
Abstract: The resurgence of continental trading blocs throughout the 1980s will influence the nature and evolution of the world economy in the 1990s and beyond. In this paper, we argue that classical economic analysis of trading blocs is inconclusive, and regionalism cannot be understood in economic terms alone. We focus on an examination of the relationship that exists between trading bloc formation and more fundamental economic and social trends taking place in the industrialized economies since the Second World War. Our contention is that regionalism represents one of the most fundamental restructuring processes affecting the world economy since the principles of international trade were established at the Bretton Woods Conference. Regionalism and multilateralism represent competing, but not necessarily mutually exclusive, principles underpinning economic integration and trade in the global economy. The end products of this competition are the two potentially complementary, spatial processes of trade bloc format...
49 citations
TL;DR: In this paper, video records of the 553 m high CN Tower have been analyzed and statistical finding are presented, including data on monthly and diurnal occurrences of lightning, as well as on parameters of incidence; such as flash duration, multiplicity of strokes in a flash and interstroke intervals.
Abstract: Lightning strikes to the 553 m high CN Tower have been observed since 1978. Video records of CN Tower lightning events during the intervening lightning seasons, up to and including 1995, have been analyzed and statistical finding are presented. The paper includes data on monthly and diurnal occurrences of lightning, as well as on parameters of incidence; such as flash duration, multiplicity of strokes in a flash and interstroke intervals. Lightning data for CN Tower strikes are also compared with observations made elsewhere in the world. Information derived is relevant to lightning protection of tall structures and of neighbouring objects, and of power line and substation components, in particular those erected in mountainous regions.
TL;DR: Wong-Rieger, D., and Quintana, D. as discussed by the authors have shown that social and psychological distance as factors in second language acquisition is a predictor of second-language acquisition.
Abstract: 27-50). Arlington, VA: Center for Applied Linguistics. Schumann, J. H. (1978b). Social and psychological distance as factors in second language acquisition. In The pidginization process: A model for second language acquisition (pp. 69-100). Rowley, MA: Newbury House. Schumann, J. H. (1978c). Social and psychological factors in second language acquisition. InJ. Richards (Ed.), Understanding second andforeign language learning (pp. 163-177). Rowley, MA: Newbury House. Wong Fillmore, L., & Valadez, C. (1986). Teaching bilingual learners. In M. Wittrock (Ed.), Handbook of research on teaching (pp. 648-685). New York: Macmillan. Wong-Rieger, D., & Quintana, D. (1987). Comparative acculturation of Southeast Asian and Hispanic immigrants and sojourners. Journal of Cross-Cultural Psychology, 18, 345-362. Young, M. Y., & Gardner, R. C. (1990). Modes of acculturation and second language proficiency. Canadian Journal of Behavioural Science, 22, 59-71.
TL;DR: The increase in fractal complexity of cerebral MFV in the patients with tilt suggests an increase in the degree of autoregulation in the Patients, and the different response of MFV-β compared with that of MAPbrain-β also indicates that MFv-β is related to the regulation of cerebral vascular resistance and not systemic blood pressure.
Abstract: We examined spectral fractal characteristics of middle cerebral artery (MCA) mean blood flow velocity (MFV) and mean arterial blood pressure adjusted to the level of the brain (MAPbrain) during gra...
TL;DR: In this article, the total body burden of specific Polychlorinated biphenyl (PCB) congeners in Lake Ontario lake trout ( Salvelinus namaycush ) was studied with a bioenergetics-based pollutant accumulation model.
TL;DR: In this article, an energy process model with geometric dostributed lag (GDL) demand, called the energy GDL process model, was updated to aid in CO2 emission control policy analysis.
TL;DR: A technique for indexing the directional detail and smoothness present in an image and map the directional information into 3-d vectors, which are then used to build N-d histograms which can be used as database indices and queried using histogram techniques.
Abstract: We present a technique for indexing the directional detail and smoothness present in an image. By directional detail we imply strong directional activity in the horizontal, vertical and diagonal direction present in areas of detail and texture. By smoothness we refer to the smooth or low frequency areas of the image which do not contain prominent edge or texture activity. We map the directional information into 3-d vectors, which are then used to build N-d histograms. These histograms can then be used as database indices which can be queried using histogram techniques.
TL;DR: In this paper, the authors present a two-step matrix model with which hotel owners and operators can evaluate their yield management strategies and quantify their effectiveness. But they do not consider the level of risk to which the investment is subjected.
Abstract: Yield management (YM) tends to emphasize revenue management, which is understandable, given the capital intensive nature of the hotel industry. To evaluate these strategies profitability or return must be assessed, together with management performance or efficiency, in the context of the level of risk to which the investment is subjected. Provides a two‐step matrix model with which hotel owners and operators can evaluate their yield management strategies and quantify their effectiveness.
TL;DR: A good correlation between the enhanced AOX removal and increasing levels of facultative bacteria developed in the conditioned sludge was observed, and the addition of sulphate into the sludge during conditioning further increased the enhancement of Aox removal when compared to sludges conditioned under nitrogen.
TL;DR: It is found that nurses can be directed to superior articles, more publication of research by nurse authors is warranted, research is being completed with little financial support, highly rated research publications tend to get funding and editorial policies affect the quality of publication.
Abstract: The purpose of this study was to assess the quality of quantitative psychiatric/mental health nursing research articles published in English between 1982 and 1992, worldwide. Criteria for selection of articles included nurse authorship or co-authorship, use of a quantitative design and pertinence to an aspect of the nursing process with psychiatric/mental health patients. One hundred and ninety-four articles met these criteria. The quality of each article was assessed by two nurse experts using Duffy's Research Appraisal Checklist (RAC). Forty-six point nine per cent of the articles were rated as superior, 50% as average and 3.1% as below average. Other findings identified journals that published research articles, countries in which research was completed, applicability of funding and qualifications of the authors. The major implications of this study are that nurses can be directed to superior articles; more publication of research by nurse authors is warranted, research is being completed with little financial support, highly rated research publications tend to get funding and editorial policies affect the quality of publication.
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01 Jan 1997TL;DR: In this paper, the authors present a chronology of the history of Cambodia, including Australia and Cambodia - the Paris Conference, Genesis of an Idea, Middle Power Diplomacy - the Red Book, Maintaining the Momentum, and the Supreme National Council.
Abstract: AbbreviationsPreface1. Australia and Cambodia - the Paris Conference2. Genesis of an Idea3. Middle Power Diplomacy - the 'Red Book'4. Maintaining the Momentum5. Texts and the Supreme National Council Begin to Emerge6. Momentum Flags7. The Slow Road to Pattaya8. The Faster Road to Paris (bis)9. Implementation of the Accords10. 'Naughty Boys'11. The Elections and Beyond12. LessonCambodian ChronologyBibliographyIndex
TL;DR: Efficient algorithms for reliable and accurate evaluatins of the complex arcsine and arccosine functions are developed in a pseudocode that has a convenient exception-handling facility.
Abstract: We develop efficient algorithms for reliable and accurate evaluatins of the complex arcsine and arccosine functions A tight error bound is derived for each algorithm; the results are valid for all machine-representable points in the complex plane The algorithms are presented in a pseudocode that has a convenient exception-handling facility Corresponding Fortran 77 programs for an IEEE environment have also been developed to illustrate the practicality of the algorithms, and these programs have been tested very carefully to help confirm the correctness of the algorithms and their error bounds The results of these tests are included in the article, but the Fortran 77 programs are not (these programs are available from Fairgrieve) Tests of other widely available programs fail at many points in the complex plane, and otherwise are slower and produce much less accurate results
TL;DR: In this paper, an energy-process model with geometric distributed lag (GDL) demand, called the energy-GDL process model, is updated to aid in energy-related CO 2 emission control policy analysis.
TL;DR: In this paper, it was shown that for high enough minimum interknot tension, the exponential spline through monotone knots will be a C2monotone curve and that Gibbs-like behaviour of the spline's derivative cannot occur in the neighbourhood of the knots.
26 May 1997
TL;DR: In this paper, a CSI-fed synchronous motor drive without using shaft sensors is presented, which can operate over a wide speed range from its rated value down to 10 rpm.
Abstract: This paper presents a high performance CSI-fed synchronous motor drive without using shaft sensors. The control algorithm is based on the estimated stator flux from the measured voltages and currents. A modified integrator suitable for AC drives is proposed in this paper, based on which the magnitude and position of the motor flux can be accurately determined even at very low motor speeds. A prototype with a DSP controller has been built to drive a 6 poles, 6 HP synchronous motor. The experimental results show that the drive system has a fast dynamic response during motor startup and speed reversal. The proposed drive can operate over a wide speed range from its rated value down to 10 rpm.
TL;DR: In this paper, game-theoretic models are developed for formally studying enforcement as it relates to environmental laws and regulations, and the key question addressed here is how variations in the severity of penalties affect violation levels and frequencies.
TL;DR: In this paper, the ability of two bacterial strains (BKME 5 and BKME 9) to grow on chemithermomechanical pulping (CTMP) effluent and degrade DHA was examined.
TL;DR: A new indexing technique is proposed, for image retrieval, which calculates the histogram of the directional detail content in a given image, which allows the use of histogram query techniques to be readily applied for retrieval.
Abstract: The authors propose a new indexing technique, for image retrieval, which calculates the histogram of the directional detail content in a given image. A multiresolution analysis is applied to extract directional information which is then mapped into three-dimensional vectors and presented as a histogram. This allows the use of histogram query techniques to be readily applied for retrieval.
TL;DR: In this paper, transverse electron scattering form factors for 0+ → 2+ excitations in 16O, 24Mg and 40Ca were calculated microscopically within the framework of the symplectic model and the results were compared with form factors calculated with collective models, for different collective flows.
TL;DR: An overview of the disease, the case history of two sisters with polyarticular arthritis is presented, and how nurses and other health team members can empower a family to manage more successfully with this disease and thereby enhance quality of life is discussed.
06 Jul 1997