bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revisiting the BE99 method for the study of outflowing gas in protostellar jets
Authors: Sperling T. , Eislöffel J. 
Published: December 2024

Context. An established method for measuring the hydrogen ionisation fraction in shock-excited gas is the BE99 method, which utilises six bright forbidden emission lines: [S II]λλ6716, 6731, [N II]λλ6548, 6583, and [O I]λλ6300, 6363. The main assumptions of this technique are that the gas is in a low-excitation state (xe < 0.3) and that the equilibrium of the underlying ionisation network is reached.
Aims. Our aim is to extend the BE99 method by including more emission lines in the blue and near-infrared part of the spectrum (λ = 3500 − 11 000 Å), and by considering higher hydrogen ionisation fractions (xe > 0.3). In addition, we investigate how a non-equilibrium state of the gas and the presence of extinction influence the BE99 technique.
Methods. We numerically solved a network of ionisation reactions in the time domain, which lead to the BE99 equilibrium. We applied the BE99 method on synthetic spectra also in the non-equilibrium state. We extented the BE99 technique to higher ionisation fractions by considering additional reactions, which involve higher ionisation states of oxygen, nitrogen, and sulphur. We tested our concepts on the low-excitation outflow of Par Lup 3−4 and the high-excitation 244−440 Proplyd in Orion.
Results. Many additional emission line ratios can in principle be exploited as extended curves (or stripes) in the (xe, Te) diagram. If the BE99 equilibrium is reached and extinction is corrected for, all stripes overlap in one location in the (xe, Te) diagram indicating the existing gas parameters. We find that the BE99 equilibrium is reached faster than the hydrogen recombination time. The application to the Par Lup 3−4 outflow shows that the classical BE99 lines together with the [N I]λλ5198+5200 lines do not meet in one location in the (xe, Te) diagram. This indicates that the gas parameters derived from the classical BE99 method are not fully consistent with other observed line ratios. A multi-line approach is necessary to determine the gas parameters. From our analysis we derive ne ∼ 45000 cm−3 − 53000 cm−3, Te = 7600 K − 8000 K, and xe ∼ 0.027 − 0.036 for the Par Lup 3−4 outflow. For the 244−440 Proplyd we were able to use the line ratios of [S II]λλ6716+6731, [O I]λλ6300+6363, and [OII]λλ7320, 7330 in the BE99 diagram to estimate the ionisation fraction at knot E3 (xe = 0.58 ± 0.05).
Conclusions. The BE99 method can be extended by utilising more emission line ratios in the (xe, Te) diagram and considering higher ionisation states. Exploiting new line ratios reveals more insights on the state of the gas. Our analysis indicates, however, that a multi-line approach is more robust in deriving gas parameters, especially for high-density gas.
C-reactive Protein, Genetic Susceptibility, and the Long-Term Risk of Venous Thromboembolism in Patients with Past Cancer
Authors: Guan Yunlong , Gan Zeyu , Li Si , Cao Xi , Zeng Ao , Li Jing , Gong Wei , Deng Jun , Hao Xingjie 
Published: December 2024

Background Several studies have indicated that C-reactive protein (CRP) level is associated with the risk of venous thromboembolism (VTE) in the general population. However, CRP appears to be unrelated to VTE events in patients newly diagnosed with cancer. As the survival time of cancer patients increases, the effect of CRP on the long-term risk of VTE may change. We aimed to investigate the association between CRP and VTE in cancer survivors and further assess the modification effect of genetic susceptibility.
Methods The Cox proportional hazards model was used to evaluate the association between CRP levels and VTE risk as well as to investigate the joint effect of CRP and genetic susceptibility. The Kaplan-Meier curve and restricted cubic spline were used to visualize the relationship between CRP and VTE.
Results This study included 27,806 participants with cancer diagnosis at baseline in the UK Biobank. Over a follow-up period of 344,636 person-years, a total of 1,151 VTE events were recorded. Participants were divided into four groups based on CRP level quartiles. The adjusted hazard ratios (95% CIs) of Q1, Q2, Q3, and Q4 were 1.00, 1.20 (0.99–1.44), 1.25 (1.04–1.50), and 1.51 (1.25–1.82), respectively. For those with high genetic risk of VTE, high CRP had an additional increased risk for VTE.
Conclusion CRP can be used as a predictive biomarker for VTE risk in cancer survivors, especially in those with high genetic risk. Future research can explore whether prevention and treatment strategies for VTE can be developed based on CRP for cancer survivors.
Effect of different crystallographic properties on the electrical conductivity of two polymorphs of a spin crossover complex
Authors: Mahbub Rifat , McElveen Kayleigh A , Zaz M Zaid , Ekanayaka Thilini K , Mishra Esha , Bissell Eric , Banerjee Parag , Shapiro David , Lai Rebecca Y , Dowben Peter A , Shield Jeffrey E 
Published: December 2024

Abstract
In this study, the structure and transport properties of two polymorphs, nanoparticles and nanorods, of the iron(II) triazole [Fe(Htrz)2(trz)](BF4) spin crossover complex were compared. Conductive atomic force microscopy was used to map the electrical conductivity of individual nanoparticles and nanorods. The [Fe(Htrz)2(trz)](BF4) nanorods showed significantly higher conductivity compared to nanoparticles. This difference in electrical conductivity is partially associated to the different Fe–N bond lengths in each of the polymorphs, with an inverse relationship between Fe–N bond length and conductivity. Transport measurements were done on the nanorods for both high spin (at 380 K) and low spin (at 320 K) states under dark and illuminated conditions. The conductance is highest for the low spin state under dark conditions. In illumination, the conductance change is much diminished.
Concentrated Solar Power Plant using air blended with nanoparticles as working fluid
Authors: Di Bartolomeo M. , Coletta A. , Deriszadeh A. , Di Battista D. , Carapellucci R. , Cipollone R. 
Published: December 2024

Abstract
Adopting efficient power plants based on renewable energy sources is extremely important to face the challenges of global warming. Concentrated Solar Power Plant (CSP) is a technology option that can achieve the decarbonization target of the electricity sector in large power plants and simultaneously meet the growing demand for electricity. In this study, a CSP plant using air as heat transfer fluid, whose transformations realize a Discrete Ericsson Cycle (DEC), was referenced. Solar fields are based on parabolic trough collectors. The DEC consists of a series of inter-cooled compressions and inter-heated expansions (four and two, respectively, in this paper), whose net result is a useful work. In this paper, a mixture of air and Cr2O3 nanoparticles at different particle concentration has been considered as working fluid to enhance the performances of the compression and expansion transformations in a DEC-based plant. The presence of particles cools the air during compression and heat the air during expansion, approaching isothermal processes. A sensitivity analysis referred to the particle concentration has been discussed and the power and the efficiency of the plant have been discussed outlining benefits and drawbacks. Nanoparticle concentration less that 0,05% in volume (10 % in mass) produce a power and efficiency output increase close to 3 % without any sensible constraint. At higher concentrations, more significant variations are achieved with a 15 % power output increase for a mass concentration of nanoparticles of 50%. Such mass concentration corresponds to just 0.05 % in volume, allowing a potential operativity of the turbomachines. In this condition, the overall CSP efficiency improve by 1.5 percentage points.
Design of a Reverse Osmosis Desalination Plant Powered by Renewables for a Small Mediterranean Island
Authors: Travaglini Riccardo , Superchi Francesco , Bianchini Alessandro 
Published: December 2024

Abstract
Water shortage is one of the main problems for small, isolated islands, especially in the Mediterranean Sea. Water supply in those areas relies on maritime transport through tanker ships, especially during periods of high demand. However, this solution is unsuitable for isolated islands due to the high costs and environmental impact. This study aims to assess the feasibility of powering a desalination facility in a remote location with renewable energy sources to assess the potential cost savings and reduction of greenhouse gas emissions compared to the current supply mechanisms. To this end, the Greek island of Tilos is selected as a case study due to its high unexploited renewable energy production during winter months. The study hypothesizes using a seawater reverse osmosis (SWRO) unit to increase the sustainability of the water supply and promote the island’s self-sufficiency. Two control strategies have been adopted, simulating a demand-driven and a renewable production-driven scenarios. Results show a levelized cost of water that ranges between 1 and 2 €/m3, which is consistent with the average cost for the existing desalination plants in Grece. The adoption of a SWRO facility coupled with water storage systems results always in a more cost-effective solution than maritime transport, leading also to a relevant reduction of the environmental impact.
A Thermodynamic Study of Pressure Gain Combustion in Combined Cycles
Authors: Giuffrida Antonio , Chiesa Paolo , Sordillo Antonio P. 
Published: December 2024

Abstract
Gas turbines are internal combustion engines based on the Brayton-Joule cycle with four thermodynamic processes including air compression, constant pressure combustion, gas expansion and heat rejection. Actually, a relevant increase in entropy production is related to the constant pressure combustion, even in the ideal cycle, so alternative combustion solutions, such as the Pressure Gain Combustion (PGC), are worthy of attention.
This work aims at investigating PGC potential in gas turbines compared to conventional power plants based on the Brayton-Joule cycle. Both simple cycle and combined cycle operations are considered, focusing on a F-class gas turbine unit for power production. Cycle performance is estimated through a thermodynamic in-house code, where the common calculation scheme has been revised in order to simulate a combustion process occurring with increasing pressure from inlet to outlet of the combustor. A booster compressor is necessarily included in the power system for delivering the cooling air to the first stage blades of the turbine. The results are fully satisfactory as PGC technology really improves the efficiency of the gas turbine expander: in case of a pressure gain of 45%, which is a reasonable value based on literature data, 1.3 to 3.4 percentage points more in gas turbine efficiency have been calculated. Finally, a parametric analysis of expansion efficiency penalties due to supersonic pulsating flows at the first stage of the turbine expander is presented.
Comparison between cold and hot network in a solar district cooling system
Authors: Ghirardi E. , Brumana G. , Franchini G. 
Published: December 2024

Abstract
Heat-powered absorption cooling have attracted attention in recent decades, especially in regions with hot and arid climates a higher availability of solar radiation, can be exploited in solar-assisted District Cooling (SDC) system to reduce costs. The paper proposes a comparison of two Solar District Cooling configurations powered by a PTC field with thermal storage and an absorption chiller. The first configuration, called cold network, has a large hot water storage tank slaved to a single chiller that produces all the chilled water that is distributed to the network; in the second configuration, called hot network, the water heated in the solar array is sent through the network directly to thermal storage tanks, located near the buildings to be served, where each agglomeration has its own chillers. A techno-economic optimization was performed for the two configurations by varying the Solar Fraction (SF), from 25% to 100%. When solar radiation is not sufficient to meet demand, an auxiliary electric chiller will be used. The results show that component size increases linearly with SF up to 75%. To achieve a fully renewable solution, components need to be significantly oversized. Generally, a SDC system in a centralized configuration offers improved performance and reduced distribution losses. However, this is not the case for a scenario with unitary SF, where the distribution network takes on an additional thermal reserve role.
Investigating the Impact of Varied C-Rates on Lithium-Ion Batteries: A 1D Simulation Study
Authors: Kaya Elif , Reina Luca , d’Adamo Alessandro 
Published: December 2024

Abstract
With the advancement of powertrain technology and progressive vehicle electrification, one of the solutions for the growing need for energy storage is batteries. A secondary battery is a device that stores electrical energy in chemical form and delivers it as electrical energy when needed (discharging), with the possibility to revert the process converting electrical to chemical energy (charging). The lithium-ion battery type used in the study offers increased energy and power density with a cell voltage of approximately 3.6 V, making it suitable for use in portable electronic devices like mobile phones and laptops. In this research, a 1D model (through-electrolyte direction) of lithium-ion battery was analysed, in which the effect of different C-rates was investigated using the battery and design module of COMSOL Multiphysics software for 0.1C, 0.5C, 1C, 2C, and 3C rates, relevant for automotive applications. The simulation results of the lithium-ion battery model constitute an important step towards the development of battery technology, allowing an understanding of the transport processes in the electrodes and electrolyte. The results revealed that under higher C-rates of operation, differences emerge in electrolyte and electrode voltage ranges, salt concentration profiles in the electrolyte, surface and center electrode particle lithium concentrations.
Lumped Parameter Modelling of Common Rail High-Pressure Fuel Injection Pump
Authors: Chiavola O , Palmieri F , Verdoliva F 
Published: December 2024

Abstract
High injection pressure is crucial for both modern and future diesel engines, resulting in enhanced performance, fuel efficiency, and reduced emissions. Fuel atomization, combustion optimization, torque control, and engine NVH are among the critical topics directly influenced by the injection strategy. Common rail diesel injection pumps play a pivotal role in delivering fuel at high pressure, with performance metrics such as flow rate and maximum pressure defining the pump’s technology level. Development efforts have consistently focused on improving performance and efficiency since the inception of common rail systems. Future challenges for diesel engines and injection pumps include meeting carbon neutrality goals, which may require adapting to new fuels, engine control strategies (such as hybrid powertrains and drivetrains), and pump drive concepts. In this context, simulating pump operation is essential for optimizing design, predicting performance, and developing control systems. The article deals with the mechanical-hydraulic modelling of a high-pressure pump. The model is based on the lumped parameter simulation of a cylinder-piston pair interacting with intake and delivery volumes via automatically opening valves. Validation of the model relies on dedicated experimental investigation campaigns, enabling measurement of pressure in the pump’s working chamber and high-speed visualization of the intake valve’s position relative to the pump shaft’s angular position. The article reports a detailed description of the model, the experimental approach, and the synthesis of the results.
Integration of hydrogen for decarbonisation: the possible contribution in “Hard-to-Abate” Sectors
Authors: Franco Alessandro , Giovannini Caterina 
Published: December 2024

Abstract
The energy transition requires significant efforts to decarbonize hard-to-abate sectors. These sectors pose substantial challenges due to their high energy demands and reliance on fossil fuels, necessitating a comprehensive strategy. Hydrogen emerges as a helpful element, through its use as a feedstock, process agent, and alternative fuel for high-temperature heat. Its use in hard-to-abate sectors, such as steel and chemical industries, offers promising low-carbon alternatives, particularly in processes like direct reduction of iron (DRI). This paper aims to provide a critical analysis and framework to better organize and address the varied challenges and activities related to hydrogen utilization in these sectors.
Optimizing hydrogen storage in magnesium hydride using carbon-based catalysts
Authors: Sarcinella Antonella 
Published: December 2024

Abstract
The utilization of fossil fuels, including coal, crude oil, and natural gas, has long been recognized as a significant contributor to environmental degradation, primarily due to their non-renewable nature and harmful emissions. The transition to renewable energy sources becomes imperative, and energy storage technologies are of paramount importance. In this context, hydrogen as chemical energy storage emerges represent a promising solution, offering both sustainability and environmental friendliness. However, the practical storage of hydrogen presents several challenges, primarily due to its light weight and gaseous nature. Among various storage methods, magnesium hydride (MgH2) has gained considerable attention due to its high hydrogen storage capacity, reversible uptake and release, and potential for safe handling and transportation. Nevertheless, magnesium hydride face inherent drawbacks, including low sorption and desorption kinetics, high hydrogen release temperatures, and the formation of undesirable gases during cycling. To overcome these challenges, various strategies have been proposed, with catalytic enhancement showing significant promise. Carbon-based materials and carbon-based composite materials have emerged as effective catalysts in improving the kinetics and efficiency of hydrogen storage in magnesium hydride. In this paper, that is a review of the existing literature, the role of these carbon-based catalysts in enhancing the performance of magnesium hydride for hydrogen storage will be explored, focusing on recent advancements and potential solutions to overcome existing limitations.
Control-Oriented Modelling of a HEV with Dual-Clutch Transmission for Torque Split and Gear Shifting Optimization
Authors: Brancati Renato , Gimelli Alfredo , Tufano Francesco 
Published: December 2024

Abstract
An innovative parallel Hybrid Electric Vehicle (HEV) configuration can be achieved using a Hybrid Dual-Clutch Transmission (H-DCT), which integrates an Electric Motor (EM) connected to one of the DCT input shafts. This configuration allows the Internal Combustion Engine (ICE) and EM to transmit torque through different mechanical paths, optimizing their operational efficiency across various driving conditions. This study develops a control-oriented model of an HEV with H-DCT for Model In the Loop (MIL) applications, incorporating detailed physical models of the DCT components. The simulation platform includes fuel consumption models for the ICE, EM, and battery, and computes vehicle motion and tractive effort using a longitudinal vehicle dynamics model. Rule-based strategies for torque-split and gear-shifting are employed to control the HEV. Validation against data from the Argonne National Laboratory (ANL) demonstrates the model accuracy and highlights the efficiency gains achievable with the H-DCT configuration.
Energy and Economic Evaluation of a Mixed-Use Renewable Energy Community
Authors: Vecchi F , Delmedico V , Castigliego D , Cafagna G , Chimienti A , Camporeale S M 
Published: December 2024

Abstract
Energy transition fosters the production of local renewable energy resources (RES) towards an active role of consumers. Renewable installations can be implemented by a single prosumer or as an aggregation of multiple users, as in the case of Renewable Energy Communities (REC). Residential users prevail in urban contexts while assessing mixed-use neighbourhoods would enhance energy load complementary. To maximise local potential for RECs, matching demand and local renewable production requires the integration of different load profiles. This would enhance the energy independence from the network and potentially have economic benefits.
This work aims at assessing the energy and economic RES convenience as single-building installation and as an aggregation in a REC. Distinct building functions are considered with multiple consumption profiles, simulated in City Energy Analyst. The considered RES is photovoltaics to satisfy the electric load. The case study is a neighbourhood in Bari, Italy, which includes residential buildings, a university, and tertiary services. Results show the advantages of a REC project rather than a scenario with single buildings. From an energy side, the electric surplus of single buildings is exchanged among them through collective self-consumption, which applies the premium tariff. Investment costs are lower for the installation of solar panels, while annual revenues increase exploiting the share of local self-consumption. The university has a far higher over-production and uncovered demand than the other structures, which greatly influences the REC outputs. Therefore, the advantage would be much more evident by realising a REC having buildings with similar magnitude of consumption and production.
Evaluating Brayton Heat Pump Potential for Industrial Decarbonisation
Authors: Benvenuti Matteo , Frate Guido Francesco , Ferrari Lorenzo 
Published: December 2024

Abstract
High-temperature heat pumps facilitate the integration of renewable into industrial processes and foster thermal production decarbonisation in industry. Among the various options available, Brayton heat pumps are increasingly researched due to their ability to produce heat at higher temperatures than the vapour-compression alternatives, for which commercial solutions are limited to up to 200 °C. While Brayton HTHPs feature a maximum heat production temperature that may easily overcome 350 °C, this technology does not produce heat at a constant temperature, such that the average temperature of the produced heat may be much lower than its maximum value and more in line with vapour compression technologies, potentially vinifying the competitive advantage of Brayton HTHPs. This paper reviews the applicability fields of Brayton HTHP, considering the maximum and minimum temperature values required by various industrial processes. Furthermore, the trade-off between the COP and the average temperature of the produced heat is explored for various Brayton HTHP configurations by considering the practical limitations that operating pressures, temperatures and mass flow rates impose on the HTHP components, namely compressors, expanders and heat exchangers. In this way, a comprehensive characterisation of the Brayton HTHP technology and its potential for industrial decarbonisation is assessed.