9 research outputs found
IN MEMORIAM PROFESSOR EMIL CHIFU (1925-1997)
No full textThis year, we commemorate the 20th death anniversary of Professor Emil Chifu. 2017 also marks 40 years from the first scientific research project proposed by Professor Chifu and accepted for exploring in cosmos by NASA (National Aeronautics and Space Administration) of the United States of America. As a prominent Romanian scientist, Professor Emil Chifu was an outstanding physical chemist, recognized by the international scientific community. He was one of the founders of the modern science of colloids, surfaces and membrane phenomena, thermodynamics and hydrodynamics of thin layers formed by surface active substances self-assembled into supramolecular structures at liquid interfaces. Professor Emil Chifu has created a modern research school in thermodynamics and physical chemistry of colloids and surfaces, at the Faculty of Chemistry and Chemical Engineering within Babes-Bolyai University in Cluj-Napoca (UBB). Currently, this school is known as the Center of Research in Physical Chemistry and is accredited within UBB
IN MEMORIAM PROFESSOR EMIL CHIFU (1925-1997)
No full textThis year, we commemorate the 20th death anniversary of Professor Emil Chifu. 2017 also marks 40 years from the first scientific research project proposed by Professor Chifu and accepted for exploring in cosmos by NASA (National Aeronautics and Space Administration) of the United States of America. As a prominent Romanian scientist, Professor Emil Chifu was an outstanding physical chemist, recognized by the international scientific community. He was one of the founders of the modern science of colloids, surfaces and membrane phenomena, thermodynamics and hydrodynamics of thin layers formed by surface active substances self-assembled into supramolecular structures at liquid interfaces. Professor Emil Chifu has created a modern research school in thermodynamics and physical chemistry of colloids and surfaces, at the Faculty of Chemistry and Chemical Engineering within Babes-Bolyai University in Cluj-Napoca (UBB). Currently, this school is known as the Center of Research in Physical Chemistry and is accredited within UBB
Real-Time Estimation of Machining Error Caused by Vibrations of End Mill
No full textAbstractThe purpose of this study is to establish a method of estimating, in real time, the machining error caused by vibrations of the cutting point of an end mill. The vibration displacement at the shank of the end mill and the dynamic cutting force were measured during cutting tests while spindle speed was increased from medium to high. It was found that the vibration displacement at the cutting point at the moment when the radial direction of the cutting edge is normal to the feed direction showed a good agreement with the height of the machined surface at a spindle speed of 4500rpm or less
Fixed Point Theorems for Generalized (α<sub>*</Sub> - Ψ)-Ciric Contractive Multivalued Operators in <i>b</I>-metric Spaces
No full textKARAPINAR, ERDAL/0000-0002-6798-3254In this paper we introduce the notion (alpha(*) - psi)- Ciric-type contractive multivalued operator and investigate the existence and uniqueness of fixed point for such a mapping in b-metric spaces. The well-posedness of the fixed point problem and the Ulam-Hyres stability is also studied. (C) 2016 All rights reserved.Romanian National Authority for Scientific Research, CNCS UEFISCDI [PN-II-ID-PCE-2011-3-0094]The first author is supported by a grant of the Romanian National Authority for Scientific Research, CNCS UEFISCDI, project number PN-II-ID-PCE-2011-3-0094
The Russian Commercial Fleet in the Treaty Ports of China in the Second Half of the 19th Century
Get PDFThe article offers a comprehensive analysis of the activity of the Russian merchant fleet in China in the second half of the 19th century. This historical issue is particularly relevant in connection with the active development of modern foreign trade in China and the strengthening of Russian-Chinese trade and economic ties. The historical research is based on the materials of the central archives of Russian Federation (including the Archive of Foreign Policy of the Russian Empire and the Russian State Historical Archive). The methodology is based on a comparative analysis of Russian shipping in China and similar activities of other foreigners, and a system analysis that allows us to study the issue in the context of the overall development of Russian-Chinese trade. An important component of the article is the statistical analysis of data on the development of maritime Russian-Chinese trade, foreign shipping in China, and freight rates. The article considers the development of the organization of maritime Russian-Chinese trade in Odessa and the Far East directions. On the example of several treaty ports (Hankou, Shanghai, and Chifu), the features of the development of Russian commercial navigation in Chinese waters and the accompanying complexities of this pro-cess are shown. As a result, the author comes to the conclusion that there is a direct correlation between the level of infrastructure development in the Russian Far East and the expansion of the presence of the Russian merchant fleet in the treaty ports of China at the end of the 19th century. © 2022, RUDN UNiversity. All rights reserved
Author Correction: Delineating COVID-19 subgroups using routine clinical data identifies distinct in-hospital outcomes
Get PDFCorrection to: Scientific Reports, published online 20 June 2023 The original version of this Article contained an error in the name of author, Andrew Scarsbrook which was incorrectly given as Prof Andrew Scarsbrook. He is a member of the NCCID Collaborative team. The original Article has been corrected
Effects of modified release hydrocortisone on restoration of early morning cortisol, quality of life, and fatigue in adrenal insufficiency (The CHAMPAIN study): a randomised, double-blind, double-dummy, cross-over study comparing Chronocort and Plenadren
Get PDF\ua9 2025 The Author(s)Background: Cortisol has a circadian rhythm with an early morning rise, loss of this rhythm is associated with poor health. Our objective was to test the hypothesis that restoring the early morning cortisol rise will improve fatigue and quality of life (QoL) by comparing twice daily Chronocort with once daily Plenadren in patients with adrenal insufficiency. Methods: A randomised, double-blind, double-dummy, cross-over study with no washout in 58 patients (29 in each arm) with primary adrenal insufficiency comparing four weeks\u27 Chronocort, 15 mg at night and 10 mg in the morning, a formulation that restores early morning cortisol levels, with four weeks’ once daily Plenadren 25 mg, which only restores daytime cortisol levels. The primary endpoint was the 07:00 h serum cortisol level and secondary endpoints measures of fatigue and QoL. The trial was registered on ClinicalTrials.gov and EU Clinical Trials Register (NCT NCT05222152; Eudract 2021-000144-21), initiated on 11th January 2022 and completed on 18th October 2023. Findings: Patients met the primary endpoint and achieved a physiological early morning serum cortisol, median 417 nmol/L on Chronocort versus 6 nmol/L on Plenadren (P < 0.0001). For secondary outcomes the majority of QoL and fatigue measures showed significant benefits for Chronocort including the disease-specific questionnaire AddiQol (P = 0.02), the fatigue questionnaire PROMIS 7b (P = 0.02), SF-36 physical component score (P = 0.01), and EQ-5D-5L (P = 0.02). The Multidimensional Assessment of Fatigue (MAF) was not significantly different between treatments; however, a pre-specified sensitivity analysis showed that in the first treatment period, Chronocort reduced the MAF Score (P = 0.008), suggesting a carry-over effect from period 1 to 2. A post hoc analysis of immune profile in a subset of 19 patients showed that those on Chronocort had an increase in circulating number or frequency of neutrophils, natural killer and natural killer T cells compared to both baseline glucocorticoid treatment and Plenadren treatment. Interpretation: Restoring the early morning cortisol levels with twice daily Chronocort 15 mg at night 10 mg in the morning improved health-related quality of life, fatigue and the immune profile compared with 25 mg daily Plenadren. Funding: Neurocrine UK Ltd
Design of an off-grid energy community: a case study of Nazareth & Puerto Estrella
No full textEsta tesis aborda el déficit de servicio eléctrico en las Zonas No Interconectadas (ZNI) de Nazareth y Puerto Estrella (Uribia, Colombia), una región con un 96% de población indígena Wayúu que recibe de 6 a 16 horas de servicio discontinuo desde una central de poligeneración diésel-fotovoltaica. Se diseña y evalúa una Comunidad Energética (CE) bajo un modelo de autogeneración colectiva y gobernanza cooperativa, adaptado a las tradiciones locales. El componente central de la propuesta es un Sistema de Gestión Energética (SGE) basado en un modelo de optimización de Programación Lineal Entera Mixta (MILP), cuyo objetivo es minimizar los costos asociados a la generación (principalmente a compra de combustible para los generadores Diesel). Este modelo se implementa con una estrategia de horizonte móvil para gestionar la planificación de un año completo (8760 horas), logrando extender el suministro eléctrico a 24 horas continuas mediante la gestión óptima del despacho y el almacenamiento de energía, basado en EGEs (Estrategias de Gestión de la energía) como seguimiento a la demanda, seguimiento al ciclo de carga de baterías y gestión a la demanda. Adicionalmente, se demuestra, a partir de una caracterización del potencial energético local, que la integración de un aerogenerador permite eliminar el uso de la generación diésel durante la operación normal, remitiéndolo a un sistema de respaldo para contingencias. El desempeño de la CE se evaluó mediante indicadores técnicos, económicos y sociales (Margen de Reserva [MR], Índice de Energía No Suministrada [IENS], SOC1, SOC2, ECO13, ENV1) a través de tres escenarios de crecimiento de la demanda (pesimista, conservador y optimista). Los resultados indican que la CE gestionada por el SGE cumple las metas de desempeño para todos los indicadores en los tres escenarios, con la excepción del indicador social SOC1, cuyas razones se analizan en el documento. Se concluye que el modelo de CE propuesto representa una alternativa técnica y económicamente viable para alcanzar la autonomía energética en comunidades remotas con características similares.LISTA DE FIGURAS 7
LISTA DE TABLAS 10
RESUMEN 12
ABSTRACT 13
1 INTRODUCCIÓN 14
2 PLANTEAMIENTO DEL PROBLEMA 16
3 MARCO REFERENCIAL 18
3.2 Marco conceptual 18
3.2.1 Trilema Energético 18
3.2.2 Comunidades energéticas 19
3.2.3 Tipos de comunidades energéticas 20
3.2.4 Usuarios o miembros de la comunidad energética 24
3.2.5 Sistema de gestión de la energía 24
3.2.6 Gestor de la comunidad energética 25
3.2.7 Generación Distribuida 25
3.2.8 Zonas no Interconectadas (ZNI) 26
3.2.9 Participación comunitaria 26
3.3 Marco teórico 28
3.3.1 Teoría del Trilema energético 28
3.3.2 Gestión sostenible de la energía 28
3.3.3 Escenarios 30
3.3.4 Estrategias 31
3.4 Marco Legal 33
3.4.1 Nacional 33
3.4.2 Internacional 37
3.5 Marco contextual 38
4 REVISIÓN BIBLIOGRÁFICA 41
4.1 Metodología de revisión sistemática de la literatura 41
4.1.1 Revisión de literatura 46
4.1.2 Indicadores asociados a las comunidades energéticas 50
4.1.3 Vacíos en la literatura y contribuciones 50
5 OBJETIVOS 52
5.2 Objetivo general 52
5.3 Objetivos específicos 52
6 METODOLOGÍA 53
6.2 Caracterización de la demanda de Nazareth y Puerto Estrella 53
6.2.1 Fuente de datos 53
6.2.2 Análisis estadístico 53
6.2.3 Hallazgos de la caracterización 60
6.2.4 Limitaciones 61
6.3 Caracterización del potencial energético disponible en Nazareth y Puerto Estrella 61
6.3.1 Fuente de datos 62
6.3.2 Análisis estadístico – recurso solar 63
6.3.3 Análisis estadístico – recurso eólico 65
6.3.1 Hallazgos de la caracterización 68
6.3.2 Limitaciones 70
6.4 Evaluación de los activos de generación de Nazareth y Puerto Estrella 70
6.4.1 Central de poligeneración de Nazareth 70
6.4.2 Hallazgos de la evaluación 73
6.5 Diseño de la comunidad energética Nazareth-Puerto Estrella (Ka'i Wa'in) 79
6.5.1 Constitución 80
6.5.2 Estructura de gobernanza 80
6.5.3 Activos disponibles y propuestos 80
6.5.4 Sistema de gestión de la energía propuesto 88
6.5.5 Limitaciones 91
6.6 Validación técnico-económica de la comunidad energética propuesta 92
6.6.1 Descripción de la simulación 93
6.6.2 Optimización MILP para minimización de costos 95
6.6.3 Evaluación financiera partir del LCOE 97
6.6.4 Planteamiento de indicadores de evaluación 99
6.6.5 Planteamiento de escenarios prospectivos de evaluación y escenario base 103
6.6.6 Análisis de sensibilidad - OPEX 108
6.6.7 Limitaciones 109
7 RESULTADOS 110
7.2 Caracterizar las necesidades energéticas y el potencial de fuentes renovables en Nazareth y Puerto Estrella 110
7.3 Desarrollar un Sistema de Gestión Energética 113
7.3.1 Escenario pesimista 113
7.3.2 Escenario conservador 116
7.3.3 Escenario optimista 119
7.4 Validar el funcionamiento del sistema de gestión de la energía (SGE) 123
7.4.1 Análisis de viabilidad técnica – Indicadores de evaluación 123
7.4.2 Análisis de viabilidad económica – LCOE 124
7.4.3 Análisis de viabilidad económica – Sensibilidad 125
8 CONCLUSIONES 134
9 REFERENCIAS BIBLIOGRÁFICAS 136
10 ANEXOS 144PregradoThis thesis addresses the electricity service deficit in the Non-Interconnected Zones (ZNI) of Nazareth and Puerto Estrella (Uribia, Colombia), a region with a 96% Wayuu Indigenous population that receives 6–16 h of intermittent service from a diesel-photovoltaic polygeneration power plant. An Energy Community (EC) is designed and evaluated under a model of collective self-generation and cooperative governance adapted to local traditions. The principal component of the proposal is an Energy Management System (EMS) based on a Mixed Integer Linear Programming (MILP) optimisation model, whose objective is to minimise the costs associated with generation (the purchase of fuel for diesel generators). This model is implemented with a rolling horizon strategy to manage planning for a full year (8,760 h), achieving 24-hour continuous power supply through optimal management of energy dispatch and storage, based on Energy Management Strategies (EMGs) such as demand following, battery charge cycle following, and demand management. In addition, based on the characterisation of local energy potential, it has been demonstrated that the integration of a wind turbine eliminates the use of diesel generators during normal operation, relegating them to a backup system for contingencies. The performance of the EC was evaluated using technical, economic, and social indicators (Reserve Margin [MR], Non-Supplied Energy Index [IENS], SOC1, SOC2, ECO13, and ENV1) through three demand growth scenarios (pessimistic, conservative, and optimistic). The results indicate that the EC managed by the EMS meets the performance targets for all indicators in the three scenarios, except for the SOC1 social indicator, the reasons for which are analysed in this study. It was concluded that the proposed EC and respective EMS model represent a technically and economically viable alternative for achieving energy autonomy in remote communities with similar characteristics.Modalidad Presencia
