MDPI - Publisher of Open Access Journals

16 pages, 406 KiB

Open AccessArticle

Forecasting the Power Generation Mix in Italy Based on Grey Markov Models

by Guglielmo D’Amico, Alex Karagrigoriou and Veronica Vigna

Energies 2024, 17(9), 2184; https://doi.org/10.3390/en17092184 - 2 May 2024

Cited by 4 | Viewed by 1326

This study considers an application of the first-order Grey Markov Model to foresee the values of Italian power generation in relation to the available energy sources. The model is used to fit data from the Italian energy system from 2000 to 2022. The integration of Markovian error introduces a random element to the model, which is able now to capture inherent uncertainties and misalignments between the Grey Model predictions and the real data. This application provides valuable insights for strategic planning in the energy sector and future developments. The results show good accuracy of the predictions, which could provide powerful information for the effective implementation of energy policies concerning the evolution of energy demand in the country. Results show an improvement in the performance of more than 50% in terms of Root Mean Squared Error (RMSE) when the Markov chain is integrated in the analysis. Despite advancements, Italy’s 2032 energy mix will still significantly rely on fossil fuels, emphasizing the need for sustained efforts beyond 2032 to enhance sustainability. Full article

(This article belongs to the Section F: Electrical Engineering)

► Show Figures

Figure 1

18 pages, 695 KiB

Open AccessEditor’s ChoiceArticle

Wind-Assisted Ship Propulsion: Matching Flettner Rotors with Diesel Engines and Controllable Pitch Propellers

by Veronica Vigna and Massimo Figari

J. Mar. Sci. Eng. 2023, 11(5), 1072; https://doi.org/10.3390/jmse11051072 - 18 May 2023

Cited by 13 | Viewed by 4909

Abstract

The harvesting of wind energy and its transformation into a thrust force for ship propulsion are gaining in popularity due to the expected benefit in fuel consumption and emission reductions. To exploit these benefits, a proper matching between the conventional diesel engine-screw propeller propulsion plant and the wind-assisted plant is key. This paper aims to present a method and a code for the preliminary sizing of a ship propulsion plant based on a diesel engine, a controllable pitch propeller, and one or more Flettner rotors. A mathematical model describing the behaviour of the rotor in terms of propulsive thrust and power is proposed. The rotor model has been integrated into an existing diesel propulsion model in order to evaluate the ship’s fuel consumption. The ship’s propulsion model is written in a parametric form with respect to the following design parameters: ship dimensions and resistance-speed curve, propeller diameter, engine power, rotor geometry, and true wind conditions. The methodology helps in evaluating the engine–propeller working points and eventually the total ship propulsive power, including the power required to spin the rotor. It provides a way to compare wind-assisted propulsive solutions in terms of fuel consumption and CO₂ emissions. A 3000-ton Ro-Ro/Pax ferry has been selected as a case study. Results on the parametric analysis of rotor dimensions and propeller pitch optimization are presented. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

8 pages, 634 KiB

Open AccessCase Report

Cyclic VLCKD Meal Replacement in a Patient with Obesity and Mild Chronic Kidney Disease following Kidney Transplantation

by Luisella Vigna, Laura Tomaino, Veronica Lotito, Maria Rosaria Ingenito, Alessandra Piontini and Alessandro Marsili

Obesities 2022, 2(4), 342-349; https://doi.org/10.3390/obesities2040028 - 14 Oct 2022

Viewed by 2729

Abstract

(1) Background: this work reports the clinical case of a man who underwent a kidney transplant at the age of 19 for idiopathic interstitial nephritis resulting in renal failure. (2) Methods: the patient also had severe obesity and underwent four cycles of a very low-calorie ketogenic diet (VLCKD) for weight loss. (3) Results: the cycles of diet therapy carried out during a six-year period allowed a significant weight loss (from 103.2 kg in 2012 to 87.5 kg in 2018) with lean mass conservation (from 49.9 kg to 52.5 kg) and a reduction of fat mass (from 53.3 kg to 35.0 kg), as assessed with bioimpedance analysis. Throughout the diet cycles, body weight remained stable, except for a weight regain that occurred between the 2nd and 3rd cycle. Renal function was preserved despite the known mild chronic kidney disease (creatininemia ranged from 1.11 mg/dL to 1.27 mg/dL, and GRF from 91 to 71 mL/min/1.73 m²). (4) Conclusions: this report shows that a VLCKD, performed under strict medical supervision, is safe and effective even in a complex clinical picture. Full article

► Show Figures

Figure 1

Search Results (3)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (3)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI