Article
Mathematics
Frank A. Plua, Francisco-Javier Sanchez-Romero, Victor Hidalgo, P. Amparo Lopez-Jimenez, Modesto Perez-Sanchez
Summary: The study proposes a new strategy to develop a mathematical model for pumps working as turbines, improving upon previous models and reducing errors in estimation by 30-50%.
Article
Energy & Fuels
Geoffrey S. Kinsey
Summary: The performance rating of solar cells and modules using a single spectrum (AM1.5) is limited. To address performance variations under different spectra, a study evaluated nine solar cell types using multiple spectra, finding that different types of solar cells exhibit different performances under various spectra.
Article
Thermodynamics
Tabbi Wilberforce, A. G. Olabi, Hegazy Rezk, Almoataz Y. Abdelaziz, Mohammad Ali Abdelkareem, Enas Taha Sayed
Summary: This study aims to determine the best conditions to boost the output power of PEMFCs. By conducting experimental work and using simulation methods, it was found that the combination of fuzzy modeling and particle swarm optimization significantly improves the cell's power output.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Shukun Wang, Zuming Liu, Chao Liu, Xiaonan Wang
Summary: This paper proposes a hybrid control strategy for the gas turbine cycle in a combined heating and power (CHP) system, which effectively improves the system's off-design performance and avoids low-temperature gas discharge. Experimental results show that this hybrid control strategy can increase system efficiency by 3.70% on average compared to traditional methods, with a maximum efficiency difference of 5.15% under specific conditions. Furthermore, the study demonstrates the application of this control strategy in a combined cooling, heating, and power (CCHP) system, showcasing its superior performance and significant reduction in energy consumption.
Article
Energy & Fuels
M. Moradi, M. Farrokhi, A. Rahimi, M. S. Hatamipour
Summary: This paper presents a mathematical modeling and experimental study of a fixed bed thermal energy recovery system by sensible heat. Different modeling levels were used to analyze the system behavior, and the models were validated against experimental data. The results showed that metal packings had the best performance in terms of system yield.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Environmental Studies
Zhaiting Yang, Huiqin Liu, Youwei Jiang, Zhuyun Zhang
Summary: Inefficiency and environmental degradation in China's resource markets are impeding the country's green economic recovery. This study examines the impact of innovative strategies on efficiency and sustainability in these markets using a NARDL model. The findings indicate that technological advancements and market-based incentives have a more immediate effect on resource market efficiency compared to policy reforms, and the impact of innovative strategies is nonlinear and asymmetric.
Article
Chemistry, Physical
Jiaqi Tan, Haoqin Hu, Shengnan Liu, Cong Chen, Dongji Xuan
Summary: This paper develops a system-level dynamic model of a PEMFC system based on MATLAB/Simulink and uses a neural network to fit the electric stack model. The effects of different operating conditions on the PEMFC system are analyzed, and the particle swarm optimization algorithm is applied to optimize the power density and system efficiency. The final optimal operating point improves the power density by 1.33% and the system efficiency by 12.8%.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Christian Langner, Elin Svensson, Simon Harvey
Summary: Heat exchanger networks in industrial heat recovery systems are often complex and subject to changes in operating conditions, necessitating extensive modeling and analytical calculations. Retrofit proposals must consider operability constraints and minimize impacts on production processes and product quality.
APPLIED THERMAL ENGINEERING
(2021)
Article
Agronomy
Xinhao Li, Tianshan Zha, Peng Liu, Charles P. -A. Bourque, Xin Jia, Yun Tian, Chuan Jin, Xiaoshuai Wei, Xinyue Liu, Hongxian Zhao, Qingfeng Xu, Shaorong Hao
Summary: Carbon gains and water losses are crucial for assessing vegetation recovery potential in drylands. This study examined the interannual variability and key controls of carbon and water vapor fluxes in a semiarid grassland ecosystem in northern China. The results suggest that temperature and atmospheric aridity play important roles in regulating carbon gains and water losses in recovering dryland vegetation, and future climate change may enhance the transition from grass to shrub cover in the region.
AGRICULTURAL AND FOREST METEOROLOGY
(2023)
Article
Chemistry, Physical
Jiangyan Yan, Zhihai Rong, Yajun Wang
Summary: A hybrid system with jointed battery and PEMFC has great potential in the field of New Energy Vehicles (NEVs), but there is still room for improvement in terms of reliability and efficiency. By establishing a PEMFC model and a complete hybrid system model, the state and performance of the system were studied, and it was found that external load has a significant impact on the pressure, water content, and voltage of the fuel cell. Additionally, the efficiency and state of charge (SOC) fluctuations of the hybrid system varied in different cycle modes.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Orthopedics
R. Michael Meneghini
Summary: The COVID-19 pandemic has reduced the volume of hip and knee arthroplasty procedures, leading to a backlog of patients in need of these elective surgeries. Therefore, increasing efficiency and productivity in patient care delivery is crucial for both current and future practices.
JOURNAL OF ARTHROPLASTY
(2021)
Article
Agriculture, Multidisciplinary
Terry J. Rose, Lee J. Kearney, Brian W. Dunn, Tina S. Dunn
Summary: The study aimed to determine the recovery of fertiliser-N in drill-sown Australian rice crops. The results showed that the recovery rate of N-15-labelled urea in grain and straw was about 50% of the applied N, and an additional 20% was recovered from roots and soil to a depth of 30 cm on both soils.
CROP & PASTURE SCIENCE
(2022)
Article
Thermodynamics
Zhiyuan Zhang, Huihua Feng, Boru Jia, Zhengxing Zuo, Xiaodong Yan, Andrew Smallbone, Anthony Paul Roskilly
Summary: Stable combustion in dual-cylinder free-piston engine generators is a challenge due to potential variations in both cycles and between cylinders. The system shows anti-interference properties but is sensitive to external conditions and operating parameters. Simulation results indicate that the system can quickly return to a stable state after single combustion variations.
Article
Thermodynamics
Nenad P. Stojic, Rade M. Karamarkovic, Miodrag Karamarkovic, Milos Nikolic
Summary: Depending on their applications, heat losses from the shells of rotary kilns account for 3-25% of the total heat input. A variable diameter annular duct is designed to utilize the heat loss, but the proximity of the kiln shell and the recuperator affects the efficiency. Various redesigns are analyzed to solve the problem.
Article
Plant Sciences
Paolo Annicchiarico, Nelson Nazzicari, Tommaso Notario, Cristina Monterrubio Martin, Massimo Romani, Barbara Ferrari, Luciano Pecetti
Summary: The study evaluated pea variation for competitive ability and associated traits, as well as the efficiency of four phenotypic or genomic selection strategies. Results showed that a greater pea proportion in mixed cropping was correlated with higher total yield, while delayed flowering and taller plant height had a significant impact on pea yield in mixed cropping. The genetic correlation for pea yield slightly exceeded 0.40 in both mixed stand and pure stand conditions.
FRONTIERS IN PLANT SCIENCE
(2021)
Article
Environmental Sciences
Joseph Daniel Pineda Sandoval, Jose Antonio Arciniega-Nevarez, Xitlali Delgado-Galvan, Helena M. Ramos, Modesto Perez-Sanchez, P. Amparo Lopez-Jimenez, Jesus Mora Rodriguez
Summary: This research proposes a methodology that uses multi-objective optimization to place pumps operating as turbines (PATs) to energize street lighting, monitor the water network, and charge small electric vehicles. The methodology selects PATs based on maximizing power recovery, minimizing system pressure, and maximizing recoverable energy. The benefits include reducing emissions, saving fuel and electricity consumption, and providing socio-economic impact. Each PAT can supply street lighting, water network monitoring, and a charging station, with a return on investment of up to 1.07 at 12 years.
Article
Physics, Fluids & Plasmas
Rodolfo Pienika, Jose Cataldo, Helena M. Ramos
Summary: This study used the open source fluid flow solver, caffa3d, to simulate the performance of a medium-scale Hydrostatic Pressure Machine (HPM) and found good correlation with experimental curves. Convergence and grid sensitivity analysis were performed to validate the simulation model.
Article
Water Resources
Helena M. Ramos, Alban Kuriqi, Oscar E. Coronado-Hernandez, P. Amparo Lopez-Jimenez, Modesto Perez-Sanchez
Summary: This research proposes a methodology to improve the accuracy and reliability of data in water systems and increase their performance. It suggests a pressure-reduction strategy and the implementation of pumps as turbines (PATs) in the Sta Cruz, Madeira water system. By using a developed digital twin model, it reduces water demand by 3.3 hm(3), increases renewable generation by 1.2 GWh, saves over 1.5 Meuro, and decreases CO2 emissions by 530 tons annually, thus contributing to sustainable development goals (SDGs) evaluation.
URBAN WATER JOURNAL
(2023)
Article
Environmental Sciences
Dalia M. Bonilla-Correa, Oscar E. Coronado-Hernandez, Vicente S. Fuertes-Miquel, Mohsen Besharat, Helena M. Ramos
Summary: The estimation of thermodynamic behavior during filling processes with entrapped air in water pipelines is a complex task, and the rigid water column (RWC) model has been used as a numerical method to predict critical points. This research presents the computation of critical points and the application of the Newton-Raphson method to obtain a unique equation for engineers to directly compute variables. The proposed formulation was validated through an experimental set of data.
Article
Environmental Sciences
Helena M. Ramos, Oscar E. Coronado-Hernandez, Pedro A. Morgado, Mariana Simao
Summary: In recent years, reversible hydro-pumping systems have gained significant interest for their flexibility, economy, and environmental benefits. Designing reversible lines requires considering dynamic effects and extreme pressures that can occur during normal and emergency operations. This research focuses on turbine operation and presents mathematical models and experimental validations for understanding the system complexity and estimating dynamic effects.
Article
Environmental Sciences
Frank A. Plua, Francisco-Javier Sanchez-Romero, Victor Hidalgo, Petra Amparo Lopez-Jimenez, Modesto Perez-Sanchez
Summary: The purpose of this study is to validate two prediction methods for flow vs. head curves using computational fluid dynamics (CFD) and mathematical models. The results show that these prediction methods are effective when a machine's operating point is close to the best efficient point (BEP). The absolute error ranges obtained with these two prediction methods for different rotation speeds are provided.
Article
Environmental Sciences
Helena M. Ramos, Alban Kuriqi, Mohsen Besharat, Enrico Creaco, Elias Tasca, Oscar E. Coronado-Hernandez, Rodolfo Pienika, Pedro Iglesias-Rey
Summary: One of the main factors contributing to water scarcity is water loss in water distribution systems, which mainly arises from a lack of knowledge in the design process and poor maintenance/management. To improve system efficiency, the current study establishes a smart water grid with a digital twin for monitoring and management. Through a case study in Madeira Island, Portugal, the developed methodology significantly reduces water losses and improves system efficiency, resulting in meaningful economic benefits.
Article
Energy & Fuels
Prajwal S. M. Guruprasad, Emanuele Quaranta, Oscar E. Coronado-Hernandez, Helena M. Ramos
Summary: This research compares batteries and pumped storage hydropower (PSH) as energy storage systems in microgrids and evaluates their economic and technical performance using the HOMER model. The results suggest that a microgrid with PSH has lower net present cost and levelized cost of energy, making it a more economical option.
Article
Environmental Sciences
Emanuele Quaranta, Helena M. M. Ramos, Ulf Stein
Summary: During the Digital Decade, the EU faces the challenges of green and digital transitions, which are interconnected. These transitions are relevant in various aspects of life, including industry, energy, transportation, environmental management, and daily life. Digital solutions have economic benefits in the water sector, such as reducing leakage, preventing sewer overflows, and improving hydropower generation. The total benefits for the EU and UK are estimated at EUR 5.0 billion, 0.14 billion, and 1.7 billion per year, respectively.
Article
Chemistry, Multidisciplinary
Duban A. Paternina-Verona, Oscar E. Coronado-Hernandez, Hector G. Espinoza-Roman, Vicente S. Fuertes-Miquel, Helena M. Ramos
Summary: In hydraulic engineering, researchers have developed mathematical and numerical tools to understand the interaction between water flow and trapped air in pipes during emptying processes. They compared experimental and numerical models and found that mathematical models offered relevant information in a short simulation time, while CFD models provided detailed visualization of complex phenomena but required longer simulation times.
APPLIED SCIENCES-BASEL
(2023)
Article
Construction & Building Technology
Camila Garcia, Petra Amparo Lopez-Jimenez, Francisco-Javier Sanchez-Romero, Modesto Perez-Sanchez
Summary: This paragraph describes a method for assessing the sustainability of water systems, using 136 indicators classified according to their intervention in the water cycle. The methodology enables the evaluation of sustainable development goals and the incorporation of new challenges to improve sustainability.
SUSTAINABLE CITIES AND SOCIETY
(2023)
Article
Water Resources
Andres F. Villalba-Barrios, Oscar E. Coronado-Hernandez, Vicente S. Fuertes-Miquel, Jairo R. Coronado-Hernandez, Helena M. Ramos
Summary: This research presents a new methodology to calculate base flow rates in gauged rivers for extreme events based on statistical correlations of daily flows. Estimating base flow rates in storm hydrographs associated with different return periods is challenging, but this methodology avoids the need for complex aquifers analysis. Computed base flow rates were validated using observed storm hydrographs, and the analysis confirmed the effectiveness of using multiannual monthly mean flows to estimate base flow for flood hydrographs with different return periods.
Article
Physics, Fluids & Plasmas
Alfredo M. Abuchar-Curi, Oscar E. Coronado-Hernandez, Jairo Useche, Veronica J. Abuchar-Soto, Argemiro Palencia-Diaz, Duban A. Paternina-Verona, Helena M. Ramos
Summary: This study conducted an experimental and numerical analysis of impeller blades in centrifugal pumps, revealing that double curvature impellers can enhance pump performance.
Article
Environmental Sciences
Elias Tasca, Mohsen Besharat, Helena M. Ramos, Edevar Luvizotto Jr, Bryan Karney
Summary: This study provides a comprehensive sensitivity analysis of the transient behavior in a rising water pipeline with an air valve. The paper examines the stages of water hammer associated with a pump trip and investigates the relationship between the transient magnitude and air valve outflow capacity. The study finds that the relationship is nonlinear and roughly follows a logistic curve shape.
