9 research outputs found

    Application of Near-Optimal Tower Control and Free Cooling on the Condenser Water Side for Optimization of Central Cooling Systems

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    This paper presents an application of tower fan control for optimization of the performance of chiller plants combined with free cooling on the condenser water side. Mathematical models including all the main components of an existing cooling plant were developed and implemented in MATLAB. Simulation results include a mapping of the performance of the plant working in free cooling mode which was used to select control parameters for free cooling operation. Then a mapping of the plant operating with chillers was developed to find the correlation between load and near-optimal air flow, which is the basis of the near-optimal tower control (NOTC) strategy. Finally, simulations were carried out using three consecutive years of historical data to predict the performance of the plant under three different control strategies: 1) tower fan control aiming to keep the temperature of the water supplied to chiller condensers at a constant set point (current control strategy), 2) NOTC and 3) NOTC and free cooling combined. Comparison of the performance of the plant with the baseline (constant condenser water temperature) shows that significant savings can be achieved through the implementation of NOTC along with free cooling. It is expected that the methodology and results of this study provide a useful framework for optimization of cooling plants

    Simulation Assessment of a Near-Optimal Control Algorithm for Central Cooling Plants with Chilled Water Storage

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    This paper presents the results of the evaluation of a control algorithm for minimizing energy costs in cooling plants with chilled water storage. The control approach requires very little plant information, is computationally simple, and is general in the sense that it is applicable to different types of utility rate structures including real-time pricing (RTP), time-of-use (TOU) and TOU with demand charges. The control algorithm was evaluated using a model of an existing chiller plant of significant complexity built in a simulation testbed for different combinations of storage sizes, load profiles and electricity rates. The performance of the near-optimal algorithm was compared with three different approaches: optimum control (baseline), and two heuristic control strategies commonly used for thermal energy storage. The energy costs obtained with the near-optimal control algorithm were within approximately 2% of the costs associated with optimal control. Comparison with the heuristic control strategies shows that significant energy savings can be achieved with the proposed control method

    La función de la Corte Penal Internacional: visiones plurales desde una perspectiva interdisciplinar

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    El presente libro hace parte de los trabajos del grupo de justicia nacional de la “Red de Investigación Perspectivas Iberoamericanas sobre la Justicia”, coordinada desde el Instituto Ibero-Americano de la Haya para la Paz, los Derechos Humanos y la Justicia Internacional (IIH) (Países Bajos). Así mismo, se inscribe dentro de los proyectos de investigación: (a) “La función de la Corte Penal Internacional desde las teorías de la justicia en el derecho internacional” (2019-2020), cofinanciado por la Facultad de Jurisprudencia de la Universidad del Rosario (Bogotá, Colombia) y el IIH (Países Bajos); y (b) “La respuesta del derecho internacional a la corrupción asociada al crimen transnacional organizado” (2019-2021), con número de referencia VFPC009, cofinanciado por la Dirección de Investigación e Innovación y la Facultad de Jurisprudencia de la Universidad del Rosario (Bogotá, Colombia), así como por el IIH (Países Bajos). Ambos proyectos se encuentran adscritos a la línea de investigación “Crítica al derecho internacional desde fundamentos filosóficos”, del Grupo de Investigación en DI de la Facultad de Jurisprudencia de la Universidad del Rosario

    Memorias semana de la Facultad de Educación. VII semana: historias, saberes y prácticas educativas innovadoras e incluyentes.

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    Las Memorias de la VII Semana de la Educación “Historias, saberes y prácticas educativas innovadoras e incluyentes”, publicadas por la Editorial de la Corporación Universitaria Minuto de Dios – UNIMINUTO, reúnen las ponencias y resúmenes sobre esta temática presentadas en un evento de realización anual, cuyo propósito es socializar experiencias investigativas y académicas de grupos, semilleros de investigación y trabajos de grado entre estudiantes y profesores de la Facultad de Educación, y con profesores y estudiantes de otras instituciones educativas que gentilmente compartieron experiencias en el campo de la educación, la pedagogía, el arte, la cultura y el deporte. El principal interés de este encuentro radica en recoger la construcción histórica educativa de la Corporación Universitaria Minuto de Dios – UNIMINUTO con respecto a sus orígenes y construcciones académicas; y las experiencias históricas de otras propuestas educativas a nivel de la educación infantil, básica, media y superior con tejido cultural y social, desde un enfoque diferencial y diverso en el cual todas las experiencias enriquecen la formación de maestros desde la innovación e inclusión en los diferentes contextos. En este encuentro participaron las universidades Antonio Nariño, de la Amazonia, del Rosario, La Gran Colombia y Pedagógica Nacional, así como la Corporación Escuela Pedagógica Experimental, el Centro Educativo de Nuestra Señora de la Paz, el Instituto Colombo Sueco y varios docentes de la Secretaría de Educación Distrital de Bogotá D. C

    Infective Endocarditis in Patients on Chronic Hemodialysis

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    International audienceInfective endocarditis (IE) is a common and serious complication in patients receiving chronic hemodialysis (HD)

    Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement

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    Abstract Background Scarce data are available comparing infective endocarditis (IE) following surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). This study aimed to compare the clinical presentation, microbiological profile, management, and outcomes of IE after SAVR versus TAVR. Methods Data were collected from the “Infectious Endocarditis after TAVR International” (enrollment from 2005 to 2020) and the “International Collaboration on Endocarditis” (enrollment from 2000 to 2012) registries. Only patients with an IE affecting the aortic valve prosthesis were included. A 1:1 paired matching approach was used to compare patients with TAVR and SAVR. Results A total of 1688 patients were included. Of them, 602 (35.7%) had a surgical bioprosthesis (SB), 666 (39.5%) a mechanical prosthesis, 70 (4.2%) a homograft, and 350 (20.7%) a transcatheter heart valve. In the SAVR versus TAVR matched population, the rate of new moderate or severe aortic regurgitation was higher in the SB group (43.4% vs 13.5%; P < .001), and fewer vegetations were diagnosed in the SB group (62.5% vs 82%; P < .001). Patients with an SB had a higher rate of perivalvular extension (47.9% vs 27%; P < .001) and Staphylococcus aureus was less common in this group (13.4% vs 22%; P = .033). Despite a higher rate of surgery in patients with SB (44.4% vs 27.3%; P < .001), 1-year mortality was similar (SB: 46.5%; TAVR: 44.8%; log-rank P = .697). Conclusions Clinical presentation, type of causative microorganism, and treatment differed between patients with an IE located on SB compared with TAVR. Despite these differences, both groups exhibited high and similar mortality at 1-year follow-up

    Clinical and genetic characteristics of late-onset Huntington's disease

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    Background: The frequency of late-onset Huntington's disease (>59 years) is assumed to be low and the clinical course milder. However, previous literature on late-onset disease is scarce and inconclusive. Objective: Our aim is to study clinical characteristics of late-onset compared to common-onset HD patients in a large cohort of HD patients from the Registry database. Methods: Participants with late- and common-onset (30–50 years)were compared for first clinical symptoms, disease progression, CAG repeat size and family history. Participants with a missing CAG repeat size, a repeat size of ≤35 or a UHDRS motor score of ≤5 were excluded. Results: Of 6007 eligible participants, 687 had late-onset (11.4%) and 3216 (53.5%) common-onset HD. Late-onset (n = 577) had significantly more gait and balance problems as first symptom compared to common-onset (n = 2408) (P <.001). Overall motor and cognitive performance (P <.001) were worse, however only disease motor progression was slower (coefficient, −0.58; SE 0.16; P <.001) compared to the common-onset group. Repeat size was significantly lower in the late-onset (n = 40.8; SD 1.6) compared to common-onset (n = 44.4; SD 2.8) (P <.001). Fewer late-onset patients (n = 451) had a positive family history compared to common-onset (n = 2940) (P <.001). Conclusions: Late-onset patients present more frequently with gait and balance problems as first symptom, and disease progression is not milder compared to common-onset HD patients apart from motor progression. The family history is likely to be negative, which might make diagnosing HD more difficult in this population. However, the balance and gait problems might be helpful in diagnosing HD in elderly patients
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