254 research outputs found

    Applying Knowledge Management to an Organization's Transformation

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    Although workers in the information age have more information at their fingertips than ever before, the ability to effectively capture and reuse actual knowledge is still a surmounting challenge for many organizations. As high tech organizations transform from providing complex products and services in an established domain to providing them in new domains, knowledge remains an increasingly valuable commodity. This paper explores the supply and demand elements of the "knowledge market" within the International Space Station and Spacecraft Processing Directorate (ISSSPD) of NASA's Kennedy Space Center (KSC). It examines how knowledge supply and knowledge demand determine the success of an organization's knowledge management (KM) activities, and how the elements of a KM infrastructure (tools, culture, and training), can be used to create and sustain knowledge supply and deman

    Exploring the epistemic politics of urban niche experiments

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    Urban experiments have been initiated in several locations to purposively initiate and shape transitions to more sustainable urban socio-technical systems, e.g. for energy, water, mobility. Although knowledges produced within such learning spaces are often presented as logical, technical and rational (Vanolo, 2013 ; Kitchin, 2014), the actors and mechanisms which shape decisions are far from obvious, involving cultures, power relations and multiple logics that are profoundly political (Machin, 2013). This research presents a case study founded in a phronetic perspective (Flyvbjerg, 2001; Avelino and Grin, 2017), unpacking the epistemological politics of an urban experiment taking place within a ‘smart city’ programme. A ‘smart transport’ application for mobile phones, ‘MotionMap’ was developed to transform the mobility system of Milton Keynes, an expanding city located 80 km to the north of London, UK. The case study recognises power relations and reveals how various actors engaged in the development of this application have further rendered the MK mobility socio-technical system an object of urban governance

    Photoelastic Method Revisited for Residual Stress Measurement in High Density Polyethylene Pipes

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    Residual stresses, also called “frozenin” stresses in highdensity polyethylene (HDPE) pipes, result from uneven cooling that occurs between the inner and outer surfaces during the extrusion process in manufacture. Most known methods of measurements involve intrusive testing to determine the magnitude and profile of the residual stresses in the pipe wall thickness. The Photoelastic Coating Technique (Photostress Method TM ) described in this paper involves capturing the locked in stresses with minimal interference and local disturbance as the residual stress is released. The existing methods used intrusive testing to determine the residual stress profile whereas the test recommended to WIS 43203 gives a single residual stress value at the bore. The Photostress Method permits stress measurements to be made directly at different points in the pipe wall and a welldefined residual stress profile was consequently obtained. An idealised equation for the residual stress profile was found it was postulated that the residual stress profile in the pipe wall can be determined once the residual stress at the pipe bore was obtained using either the WIS method or the Photostress Method

    Autonomous Light Management in Flexible Photoelectrochromic Films Integrating High Performance Silicon Solar Microcells

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    Commercial smart window technologies for dynamic light and heat management in building and automotive environments traditionally rely on electrochromic (EC) materials powered by an external source. This design complicates building-scale installation requirements and substantially increases costs for applications in retrofit construction. Self-powered photoelectrochromic (PEC) windows are an intuitive alternative wherein a photovoltaic (PV) material is used to power the electrochromic device, which modulates the transmission of the incident solar flux. The PV component in this application must be sufficiently transparent and produce enough power to efficiently modulate the EC device transmission. Here, we propose Si solar microcells (ÎŒ-cells) that are i) small enough to be visually transparent to the eye, and ii) thin enough to enable flexible PEC devices. Visual transparency is achieved when Si ÎŒ-cells are arranged in high pitch (i.e. low-integration density) form factors while maintaining the advantages of a single-crystalline PV material (i.e., long lifetime and high performance). Additionally, the thin dimensions of these Si ÎŒ-cells enable fabrication on flexible substrates to realize these flexible PEC devices. The current work demonstrates this concept using WO₃ as the EC material and V₂O₅ as the ion storage layer, where each component is fabricated via sol-gel methods that afford improved prospects for scalability and tunability in comparison to thermal evaporation methods. The EC devices display fast switching times, as low as 8 seconds, with a modulation in transmission as high as 33%. Integration with two Si ÎŒ-cells in series (affording a 1.12 V output) demonstrates an integrated PEC module design with switching times of less than 3 minutes, and a modulation in transmission of 32% with an unprecedented EC:PV areal ratio

    Acid-base changes and acetate metabolism during routine and high-efficiency hemodialysis in children

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    Acid-base changes and acetate metabolism during routine and high-efficiency hemodialysis in children. Changes in acid-base status and plasma acetate concentrations were studied in eight children during 11 hemodialysis sessions. During dialysis, the blood bicarbonate concentration fell (20.5 ± 0.7 to 19.6 ± 0.8 mEq/liter), the PCO2 fell (33.4 ± 0.8 to 27.5 ± 1.4 mm Hg), and the pH rose (7.42 ± 0.01 to 7.48 ± 0.02). During the hour after dialysis, the bicarbonate concentration rose to normal (23.4 ± 0.7 mEq/liter), the PCO2 rose (32.8 ± 0.8 mm Hg), and the pH remained unchanged. The half-life of plasma acetate, measured after dialysis, was 8.7 min. During five “high-efficiency” dialysis sessions (urea clearance, > 3.0 ml/min/kg), blood bicarbonate concentration fell 3.2 mEq/liter, PCO2 fell 8.7 mm Hg, and plasma acetate rose to 7.51 mmoles/liter, whereas during six “routine efficiency” dialysis sessions (urea clearance, 1.5 to 3.0 ml/min/kg), blood bicarbonate rose 1.0 mEq/liter, PCO2 fell 36 mm Hg, and plasma acetate rose to 3.52 mmoles/liter. At 1 hour after the end of dialysis, blood bicarbonate, PCO2, and plasma acetate concentrations were similar in the two groups. Clinical problems occurred more frequently in the high-efficiency group during dialysis although the difference was not significant. The data indicate that (1) dialysis with acetate buffer effectively corrects pre-dialysis metabolic acidosis, (2) although children have a high rate of acetate metabolism, during high-efficiency dialysis this rate is exceeded by the influx of acetate, and acid-base abnormalities occur. These abnormalities are transient but may cause clinical problems.Modifications acido-basiques et mĂ©tabolisme de l'acĂ©tate au cours de l'hĂ©modialyse de routine ou Ă  efficacitĂ© Ă©levĂ©e chez l'enfant. Les modifications de l'Ă©tat acido-basique et des concentrations plasmatiques d'acĂ©tate ont Ă©tĂ© Ă©tudiĂ©es chez huit enfants au cours de 11 sĂ©ances d'hĂ©modialyse. Au cours de la dialyse les bicarbonates diminuent (20,5 ± 0,7 Ă  19,6 ± 0,8 mEq/ litre), la PCO2 diminue (33,4 ± 0,8 Ă  27,5 ± 1,4 mm Hg), et le pH augmente (7,42 ± 0,01 Ă  7,48 ± 0,02). Au cours de l'heure qui suit la dialyse les bicarbonates s'Ă©lĂšvent Ă  une valeur normale, 23,4 ± 0,07 mEq/litre, la PCO2 s'Ă©lĂšve Ă  32,8 ± 0,8 mm Hg, et le pH est inchangĂ©. La demi vie de l'acĂ©tate plasmatique, mesurĂ©e aprĂšs la dialyse, Ă©tait de 8,7 min. Au cours de cinq sĂ©ances de dialyse Ă  haute efficacitĂ© (clearance de l'urĂ©e, > 3,0 ml/min/kg) les bicarbonates baissent de 3,2 mEq/litre, la PCO2 de 8,7 mm Hg, et l'acĂ©tate plasmatique s'est Ă©levĂ© Ă  7,51 mmoles/litre alors qu'au cours de six sĂ©ances de dialyse d'efficacitĂ© moyenne (clearance de l'urĂ©e, 1,5 Ă  3,0 ml/min/kg) les bicarbonates ont augmentĂ© de 1,0 mEq/litre, la PCO2 a diminuĂ© de 3,6 mm Hg, et l'acĂ©tate plasmatique s'est Ă©levĂ© Ă  3,52 mmoles/litre. Une heure aprĂšs la fin de la dialyse les bicarbonates, la PCO2 et l'acĂ©tate plasmatique Ă©taient semblables dans les deux groupes. Des problĂšmes cliniques sont survenus plus souvent au cours de la dialyse dans le groups Ă  haute efficacitĂ© bien que la diffĂ©rence ne soit pas significative. Ces rĂ©sultats indiquent que (1) la dialyse avec le tampon acĂ©tate corrige efficacement l'acidose mĂ©tabolique prĂ©-dialytique, (2) bien que l'enfant ait une capacitĂ© Ă©levĂ©e de mĂ©taboliser l'acĂ©tate, cette capacitĂ© est dĂ©bordĂ©e, au cours de la dialyse Ă  haute efficacitĂ©, par l'entrĂ©e d'acĂ©tate et des anomalies acidobasiques surviennent. Ces anomalies sont transitoires et peuvent dĂ©terminer des problĂšmes cliniques

    The Effect of Chronic Digitoxin Administration on the Contractile State of Normal and Nonfailing Hypertrophied Myocardium

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    A B S T R A C T To determine the effect of prolonged digitoxin administration on contractile function of nonfailing myocardium, right ventricular papillary muscle mechanics were examined after 6 or 24 wk of glycoside administration to control and pulmonary artery banded cats. Resting length-tension relations were not affected by digitoxin; however, isometrically developed force and the maximal rate of force development at the peak of the length-tension curve were increased in all treated groups. In untreated animals, banding resulted in a 28% incidence of deaths from heart failure. 6 wk after constriction, contractile function was depressed whereas normal function was observed 24 wk after banding. Digitoxin significantly reduced mortality from heart failure and enhanced the recovery of contractile function; contractile function in the 6 wk banded treated group approached that of untreated control and 24-wk banded groups. The long-term effects of digitoxin on contractile function were not importantly related to the temporal association between banding and institution of glycoside administration. Development of myocardial hypertrophy was comparable in treated and untreated banded groups. These results demonstrate that a significant positive inotropic effect persists in both normal and nonfailing hypertrophied myocardium during chronic digitoxin administration

    Autonomous Light Management in Flexible Photoelectrochromic Films Integrating High Performance Silicon Solar Microcells

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    Commercial smart window technologies for dynamic light and heat management in building and automotive environments traditionally rely on electrochromic (EC) materials powered by an external source. This design complicates building-scale installation requirements and substantially increases costs for applications in retrofit construction. Self-powered photoelectrochromic (PEC) windows are an intuitive alternative wherein a photovoltaic (PV) material is used to power the electrochromic device, which modulates the transmission of the incident solar flux. The PV component in this application must be sufficiently transparent and produce enough power to efficiently modulate the EC device transmission. Here, we propose Si solar microcells (ÎŒ-cells) that are i) small enough to be visually transparent to the eye, and ii) thin enough to enable flexible PEC devices. Visual transparency is achieved when Si ÎŒ-cells are arranged in high pitch (i.e. low-integration density) form factors while maintaining the advantages of a single-crystalline PV material (i.e., long lifetime and high performance). Additionally, the thin dimensions of these Si ÎŒ-cells enable fabrication on flexible substrates to realize these flexible PEC devices. The current work demonstrates this concept using WO₃ as the EC material and V₂O₅ as the ion storage layer, where each component is fabricated via sol-gel methods that afford improved prospects for scalability and tunability in comparison to thermal evaporation methods. The EC devices display fast switching times, as low as 8 seconds, with a modulation in transmission as high as 33%. Integration with two Si ÎŒ-cells in series (affording a 1.12 V output) demonstrates an integrated PEC module design with switching times of less than 3 minutes, and a modulation in transmission of 32% with an unprecedented EC:PV areal ratio
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