745 research outputs found
Control híbrido del péndulo de furuta
Este proyecto muestra el modelado matemático del péndulo de furuta mediante funciones de energía, teniendo en cuenta las dinámicas no lineales propias de los sistemas físicos y considerando los acoples existentes entre los dispositivos eléctricos y mecánicos. Se desarrolla un proceso de control basado en realimentación de variables de estado para el punto de equilibrio y se abordan dos temáticas para la zona no lineal de la planta. En primera instancia se implementan las funciones que representan los estados energéticos de la planta en forma global y se establecen las regiones de operación (zona de "Swing UP") y finalmente se emplean redes neuronales (RNA) para emular el comportamiento de las funciones de energía.
Se presenta la combinación de las técnicas de control considerando las restricciones propias del actuador y sensores utilizados, además se presenta un estudio de fenómenos físicos que pueden alterar el comportamiento del sistema
LQR-Based adaptive virtual inertia for grid integration of wind energy conversion system based on synchronverter model
This paper proposes adaptive virtual inertia for the synchronverter model implemented in a wind turbine generator system integrated into the grid through a back-to-back converter. A linear dynamic system is developed for the proposed adaptive virtual inertia, which employs the frequency deviation and the rotor angle deviation of the synchronverter model as the state variables and the virtual inertia and frequency droop gain as the control variables. In addition, the proposed adaptive virtual inertia uses a linear quadratic regulator to ensure the optimal balance between fast frequency response and wind turbine generator system stress during disturbances. Hence,
it minimizes frequency deviations with minimum effort. Several case simulations are proposed and carried out in MATLAB/Simulink software, and the results demonstrate the effectiveness and feasibility of the proposed adaptive virtual inertia synchronverter based on a linear quadratic regulator. The maximum and minimum frequency, the rate change of the frequency, and the integral of time-weighted absolute error are computed to quantify the performance of the proposed adaptive virtual inertia. These indexes are reduced by 46.61%, 52.67%, 79.41%, and 34.66%, in the worst case, when the proposed adaptive model is compared to the conventional synchronverter model
Optimal Economic–Environmental Operation of BESS in AC Distribution Systems: A Convex Multi-Objective Formulation
This paper deals with the multi-objective operation of battery energy storage systems
(BESS) in AC distribution systems using a convex reformulation. The objective functions are CO2
emissions, and the costs of the daily energy losses are considered. The conventional non-linear
nonconvex branch multi-period optimal power flow model is reformulated with a second-order cone
programming (SOCP) model, which ensures finding the global optimum for each point present in the
Pareto front. The weighting factors methodology is used to convert the multi-objective model into a
convex single-objective model, which allows for finding the optimal Pareto front using an iterative
search. Two operational scenarios regarding BESS are considered: (i) a unity power factor operation
and (ii) a variable power factor operation. The numerical results demonstrate that including the
reactive power capabilities in BESS reduces 200 kg of CO2 emissions and USD 80 per day of operation.
All of the numerical validations were developed in MATLAB 2020b with the CVX tool and the
SEDUMI and SDPT3 solver
A Targeted Approach by High Resolution Mass Spectrometry to Reveal New Compounds in Raisins
Raisins are dried grapes mostly obtained from cultivars of Vitis vinifera L. and are extensively consumed worldwide. They are rich in bioactive compounds such as polyphenols, which are associated with a broad range of health benefits. The aim of the present study was to compare the phenolic profiles of three di erent raisin varieties (Thompson seedless, Muscat, and sultanas). Total polyphenols (TPs) were evaluated by the Folin-Ciocalteu (F-C) assay and significant differences were observed among all raisin varieties. Furthermore, liquid chromatography coupled with electrospray ionization hybrid linear ion trap quadrupole-Orbitrap-mass spectrometry (LC/ESI-LTQ-Orbitrap-MS) was employed for the comprehensive identification of phenolic constituents. A total of 45 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavanoids, flavonoids, flavonols, flavones,and stilbenoids. The three varieties of raisins showed a similar phenolic profile, although the highest number of phenolic compounds was identified in Muscat raisins owing to the roanthocyanidins extracted from their seeds, while stilbenoids were not detected in the Thompson variety
Is eating raisins healthy?
Raisins are dried grapes consumed worldwide that contain beneficial components for human health. They are rich in fiber and phytochemicals such as phenolic compounds. Despite a 60% sugar content, several studies have reported health-promoting properties for raisins and this review compiles the intervention studies, as well as the cell line and animal model studies carried out to date. It has been demonstrated that raisins possess a low-to-moderate glycemic index, which makes them a healthy snack. They seem to contribute to a better diet quality and may reduce appetite. Their antioxidant capacity has been correlated to the phenolic content and this may be involved in the improvement of cardiovascular health. In addition, raisins maintain a good oral health due to their antibacterial activity, low adherence to teeth and an optimum oral pH. Raisin consumption also seems to be favorable for colon function, although more studies should be done to conclude this benefit. Moreover, gut microbiota could be affected by the prebiotic content of raisins. Cell line and animal model studies show other potential benefits in specific diseases, such as cancer and Alzheimer's disease. However, deeper research is required and future intervention studies with humans are needed. Overall, incorporating an 80-90 g portion of raisins (half a cup) into the daily diet may be favorable for human health
Phenolic Profile of Grape Canes: Novel Compounds Identified by LC-ESI-LTQ-Orbitrap-MS
Grape canes (Vitis vinifera L.) are a viticulture industry by-product with an important content of secondary metabolites, mainly polyphenols with a broad spectrum of demonstrated health benefits. Grape canes, therefore, have considerable economic potential as a source of high-value phytochemicals. In this work, liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole-Orbitrap mass spectrometry (LC-LTQ-Orbitrap) was used for the comprehensive identification of polyphenolic compounds in grape canes. Identification of polyphenols was performed by comparing their retention times, accurate mass measured, and mass fragmentation patterns with those of reference substances or available data in the literature. A total of 75 compounds were identified, including phenolic acids, flavanols, flavonols, flavanonols, flavanones, and stilbenoids. The most abundant polyphenols were proanthocyanidins and stilbenoids and their oligomers. Moreover, the high-resolution mass spectrometry analysis revealed the occurrence of 17 polyphenols never described before in grape canes, thereby providing a more complete polyphenolic profile of this potentially valuable by-product
Bench-scale extraction of stilbenoids and other phenolics from stored grape canes (Vitis vinifera): Optimization process, chemical characterization, and potential protection against oxidative damage
Dietary supplements have become the key to complement deficiencies in the occidental diet and therefore to reduce the incidence of oxidative stress related diseases. A bench-scale extraction procedure was studied to obtain a valuable product rich in phenolic compounds and antioxidant capacity from Pinot Noir grape cane enhanced by storage. Extraction solvent, cane-size, solid:liquid ratio, temperature, and extraction time, were systematically evaluated in order to obtain a natural functional product. Complete chemical characterization of a Pinot Noir grape cane extract produced under bench scale process is presented for the first time. Phenolic profiles of the extracts were characterized by HPLC-PDA-MS/MS and minerals by ICP-OES. Proteins, carbohydrates and lignins were also evaluated. The main phenolic compounds in the final product were stilbenoids, flavan-3-ols, procyanidins, and flavonols, with 6.53%, 4.84%, 2.11%, and 0.25%, respectively on a dry matter basis. Other chemical constituents were carbohydrates (27%), minerals (1%) and lignins (38.7%). The antioxidant capacity of the product was demonstrated using chemical assays (TEACABTS/CUPRAC and ORAC-FL) and endothelial cells model. The extract produced under the described bench scale process using grape cane enhanced by storage have a chemical composition and protecting capacities to be used in functional foods industry
Grape cane extracts: an opportunity for the development of novel additives for food Chilean industry
Podeu consultar el III Workshop anual INSA-UB complet a: http://hdl.handle.net/2445/118993Sessió 2. Pòster núm. 1
Comparación de eficacia analgésica dexketoprofeno 50 mg Versus Metamizol 3g en pacientes sometidos a colecistectomía laparoscópica, Hospital Militar Escuela Dr. Alejandro Dávila Bolaños, Junio-Octubre 2014
El dolor está definido según la OMS que el dolor es una experiencia sensorial y emocional (subjetiva), generalmente desagradable, que pueden experimentar todos aquellos seres vivos que disponen de un sistema nervioso central. Es una experiencia asociada a una lesión tisular o expresada como si ésta existiera, Los analgésicos no esteroideos (AINES) han tomado gran protagonismo en el tratamiento del dolor postquirúrgico ya sea comoresfuerzo de los analgésicos opioides o como terapia de elección, estos por sus ventajas ante los narcóticos tales como: menores efectos colaterales, pronta rehabilitación (fármaco dependencia, depresión respiratoria, fenómenos alérgicos, mareos, etc.), pronta rehabilitación y retorno a las actividades normales. Esta familia de fármacos es extensa, la mayoría son ácidosorgánicos, presentando diferentes estructuras químicas, y compartiendo acciones similares, lo cual a su vez lo haces diferenciarse en cuanto potencia gástrolesivas. Poder antiinflamatorio, etc. Es por ello que en este estudio se compara dos analgésicos con características similares y potencias diferentes en el tratamiento del dolor postquirúrgico en pacientes sometidos a colecistectomía, como lo son el Dexketoprofeno y Metamizol, teniendo como hipótesis: El Dexketoprofeno 50mg en comparación con el Metamizol 3g tiene mayor efectividad analgésica para el alivio del dolor postquirúrgico en pacientes sometidos a cirugías laparoscópicas.
Este estudio es de tipo ensayo clínico realizado en el Hospital militar escuela Dr. Alejandro Dávila Bolaños, siendo el objetivo general Comparar eficacia analgésica Dexketoprofeno 50 mg Versus Metamizol 3g en pacientes sometidos a colecistectomía laparoscópica, en el Hospital Militar Escuela Dr. Alejandro Dávila Bolaños, Junio - Octubre 2014.con muestra de 40 pacientes, mismos que al azar fue dividida en grupo A y Grupo B. los resultados obtenidos indicaron que el manejo del dolor postquirúrgico en relación al Dexketoprofeno versus Metamizol, obtuvieron los mismos resultados en cuanto al alivio del dolor, pero es importante mencionar que el Dexketoprofeno lo hace a menores dosis y presenta menores reacciones adversas
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