bluuebunny/crossref_metadata_2025 huggingface dataset:
[18F]FDG Uptake in Non-Infected Endovascular Grafts: A Retrospective Study
Authors: Lauri Chiara , Signore Alberto , Campagna Giuseppe , Aloisi Francesco , Taurino Maurizio , Sirignano Pasqualino
Published: January 2023

Purpose: After endovascular aneurysm repair (EVAR), an increased [18F]FDG uptake may be observed at PET/CT, being common to both vascular graft/endograft infection (VGEI) and sterile post-surgical inflammation. Increased non-specific metabolic activity, due to foreign body reaction, can persist for several years after surgery, thus complicating the interpretation of PET/CT studies. In this paper, we aimed to assess [18F]FDG distribution at different time-points after the implant of abdominal Endurant® endografts in patients without suspicion of infection. Methods: We retrospectively evaluated [18F]FDG/CT in 16 oncological patients who underwent abdominal aortic aneurysm exclusion with Endurant® grafts. Patients had no clinical suspicion of infection and were followed up for at least 24 months after scan. [18F]FDG PET/CT scans were interpreted using both visual and semi-quantitative analyses. Results: The time between the EVAR procedure and [18F]FDG PET/CT ranged between 1 and 36 months. All grafts showed mild and diffuse [18F]FDG uptake without a focal pattern. Mean values of SUVmax were 2.63 ± 0.48 (95% CI 2.38–2.88); for SUVmean 1.90 ± 0.33 (95% CI 1.72–2.08); for T/B ratios 1.43 ± 0.41 (95% CI 1.21–1.65). SUVmax and SUVmean were not correlated to the time elapsed from the procedure, but we observed a declining trend in T/B ratio over time. Conclusions: Endovascular implant of Endurant® grafts does not cause a significant inflammatory reaction. The evidence of faint and diffuse [18F]FDG uptake along the graft can reliably exclude an infection, even in early post-procedural phases. Therefore, in patients with a low probability of VGEI, [18F]FDG PET/CT can also be performed immediately after EVAR.
Suboptimal Chest Radiography and Artificial Intelligence: The Problem and the Solution
Authors: Dasegowda Giridhar , Kalra Mannudeep K. , Abi-Ghanem Alain S. , Arru Chiara D. , Bernardo Monica , Saba Luca , Segota Doris , Tabrizi Zhale , Viswamitra Sanjaya , Kaviani Parisa , Karout Lina , Dreyer Keith J.
Published: January 2023

Chest radiographs (CXR) are the most performed imaging tests and rank high among the radiographic exams with suboptimal quality and high rejection rates. Suboptimal CXRs can cause delays in patient care and pitfalls in radiographic interpretation, given their ubiquitous use in the diagnosis and management of acute and chronic ailments. Suboptimal CXRs can also compound and lead to high inter-radiologist variations in CXR interpretation. While advances in radiography with transitions to computerized and digital radiography have reduced the prevalence of suboptimal exams, the problem persists. Advances in machine learning and artificial intelligence (AI), particularly in the radiographic acquisition, triage, and interpretation of CXRs, could offer a plausible solution for suboptimal CXRs. We review the literature on suboptimal CXRs and the potential use of AI to help reduce the prevalence of suboptimal CXRs.
A Novel Inflammatory Marker for the Diagnosis of Hashimoto’s Thyroiditis: Platelet-Count-to-Lymphocyte-Count Ratio
Authors: Erge Eray , Kiziltunc Cagri , Balci Sumeyye Buse , Atak Tel Burcin Meryem , Bilgin Satilmis , Duman Tuba Taslamacioglu , Aktas Gulali
Published: January 2023

Background: Hashimoto’s thyroiditis (HT) is a chronic autoimmune thyroiditis that causes systemic inflammation in the body, leading to hypothyroidism and an enlargement of the thyroid gland. Objectives: This study aims to reveal whether there is a relationship between Hashimoto’s thyroiditis and the platelet-count-to-lymphocyte-count ratio (PLR), which is used as a new inflammatory marker. Methods: In this retrospective study, we compared the PLR of the euthyroid HT group and the hypothyroid-thyrotoxic HT group to the controls. We also evaluated the values of thyroid-stimulating hormone (TSH), free T4 (fT4), C-reactive protein (CRP), aspartate transaminase (AST), alanine transaminase (ALT), white blood cell count, lymphocyte count, hemoglobin, hematocrit, and platelet count in each group. Results: The PLR of the subjects with Hashimoto’s thyroiditis was found to be significantly different from the control group (p < 0.001), with the rankings as follows: hypothyroid-thyrotoxic HT 177% (72–417) > euthyroid HT 137% (69–272) > control group 103% (44–243). In addition to the increased PLR values, an increase in CRP values was also observed, revealing a strong positive correlation between the PLR and CRP in the HT patients. Conclusion: In this study, we found out that the PLR was higher in the hypothyroid-thyrotoxic HT and euthyroid HT patients than in a healthy control group.
Generalized Survival Probability
Authors: Zarate-Herrada David A. , Santos Lea F. , Torres-Herrera E. Jonathan
Published: January 2023

Survival probability measures the probability that a system taken out of equilibrium has not yet transitioned from its initial state. Inspired by the generalized entropies used to analyze nonergodic states, we introduce a generalized version of the survival probability and discuss how it can assist in studies of the structure of eigenstates and ergodicity.
ELAA: An Ensemble-Learning-Based Adversarial Attack Targeting Image-Classification Model
Authors: Fu Zhongwang , Cui Xiaohui
Published: January 2023

The research on image-classification-adversarial attacks is crucial in the realm of artificial intelligence (AI) security. Most of the image-classification-adversarial attack methods are for white-box settings, demanding target model gradients and network architectures, which is less practical when facing real-world cases. However, black-box adversarial attacks immune to the above limitations and reinforcement learning (RL) seem to be a feasible solution to explore an optimized evasion policy. Unfortunately, existing RL-based works perform worse than expected in the attack success rate. In light of these challenges, we propose an ensemble-learning-based adversarial attack (ELAA) targeting image-classification models which aggregate and optimize multiple reinforcement learning (RL) base learners, which further reveals the vulnerabilities of learning-based image-classification models. Experimental results show that the attack success rate for the ensemble model is about 35% higher than for a single model. The attack success rate of ELAA is 15% higher than those of the baseline methods.
Direct Enforcement in Belgium with High Speed Weigh-in-Motion (HS-WIM)
Authors: Warscotte Loïc , Boreux Jehan , Antofie Adriana , Corbaye Dominique
Published: January 2023

Interest for high speed weigh-in-motion of vehicles, or HS-WIM keeps growing worldwide. The main purpose of such systems is checking weights of vehicles in a self manner, in order to impose a penalty to overloaded ones. Overloaded vehicles may cause several problems such as safety issues, road deterioration or unfair competition. Walloon Public Service (WPS) has dealt with the settings and approval of a HS-WIM system in Belgium. The latest resurfacing of the roadway around the prototype provides good-quality data that allows for reaching excellent results in terms of accuracy of the weight estimation. Therefore, direct weight enforcement may be activated since the system has a type approval certificate to be used in accordance with legal metrology requirements.
A Visualization-Based Ramp Event Detection Model for Wind Power Generation
Authors: Fu Junwei , Ni Yuna , Ma Yuming , Zhao Jian , Yang Qiuyi , Xu Shiyi , Zhang Xiang , Liu Yuhua
Published: January 2023

Wind power ramp events (WPREs) are a common phenomenon in wind power generation. This unavoidable phenomenon poses a great harm to the balance of active power and the stability of frequency in the power supply system, which seriously threatens the safety, stability, and economic operation of the power grid. In order to deal with the impact of ramp events, accurate and rapid detection of ramp events is of great significance for the formulation of response measures. However, some attribute information is ignored in previous studies, and the laws and characteristics of ramp events are difficult to present intuitively. In this paper, we propose a visualization-based ramp event detection model for wind power generation. Firstly, a ramp event detection model is designed considering the multidimensional attributes of ramp events. Then, an uncertainty analysis scheme of ramp events based on the confidence is proposed, enabling users to analyze and judge the detection results of ramp events from different dimensions. In addition, an interactive optimization model is designed, supporting users to update samples interactively, to realize iterative optimization of the detection model. Finally, a set of visual designs and user-friendly interactions are implemented, enabling users to explore WPREs, judge the identification results, and interactively optimize the model. Case studies and expert interviews based on real-world datasets further demonstrate the effectiveness of our system in the WPREs identification, the exploration of the accuracy of identification results, and interactive optimization.
Clean Hydrogen Is a Challenge for Enterprises in the Era of Low-Emission and Zero-Emission Economy
Authors: Borowski Piotr F. , Karlikowska Barbara
Published: January 2023

Hydrogen can be considered an innovative fuel that will revolutionize the energy sector and enable even more complete use of the potential of renewable sources. The aim of the paper is to present the challenges faced by companies and economies that will produce and use hydrogen. Thanks to the use of hydrogen in the energy, transport and construction sectors, it will be possible to achieve climate neutrality by 2050. By 2050, global demand for hydrogen will increase to 614 million metric tons a year, and thanks to the use of hydrogen in energy, transport and construction, it will be possible to achieve climate neutrality. Depending on the method of hydrogen production, the processes used and the final effects, several groups can be distinguished, marked with different colors. It is in this area of obtaining friendly hydrogen that innovative possibilities for its production open up. The costs of hydrogen production are also affected by network fees, national tax systems, availability and prices of carbon capture, utilization, and storage installations, energy consumption rates by electrolyzers and transport methods. It is planned that 1 kg of hydrogen will cost USD 1. The study used the desk research method, which made it possible to analyze a huge amount of descriptive data and numerical data.
A Virtual Impedance-Based Flying Start Considering Transient Characteristics for Permanent Magnet Synchronous Machine Drive Systems
Authors: Lee Yoon-Seong , Choo Kyoung-Min , Jeong Won-Sang , Lee Chang-Hee , Yi Junsin , Won Chung-Yuen
Published: January 2023

A virtual impedance-based flying start considering transient characteristics for permanent magnet synchronous machine drive systems is proposed. The conventional flying start based on virtual resistance (VR) assumes that the load of the system is resistive. However, the maximum value of VR, which is determined by the machine parameter and sampling frequency, is sometimes small. In this case, the load of the system is non-resistive. This assumption error causes an estimated position error and degrades transient characteristics. In the proposed method, algebraic-type virtual inductance (VI) is added to the estimation current regulator of the flying start based on VR. This change improves the accuracy of the estimated rotor position and the transient characteristics. In addition, the discrete-time system model of the proposed flying start method is given, the stability was analyzed considering the change in VR caused by the proposed method, and the improvements were verified by PSIM simulations and experimental results.
Considering Forward Electricity Prices for a Hydro Power Plant Risk Analysis in the Brazilian Electricity Market
Authors: Lauro Arthur , Kitamura Daniel , Lima Waleska , Dias Bruno , Soares Tiago
Published: January 2023

The Brazilian Power System is mainly composed of renewable generation from hydroelectric and wind. Hence, spot and forward electricity prices tend to represent the inherently stochastic nature of these resources, while risk management is a measure taken by agents, especially hydro power plants (HPPs) to hedge against deep financial losses. A HPP goal is to maximize its profit considering uncertainties in forward electricity prices, spot prices, and generation scaling factor (GSF) for years ahead. Therefore, the objective of this work is to simulate the real decision-making process of a HPP, where they need to have a perspective of the forward market and future spot price assessment to negotiate forward electricity contracts. To do so, the present work models the uncertainty in electricity forward prices via two-stage stochastic programming, assessing the benefits of the stochastic solution in comparison to the deterministic one. In addition, different risk aversion levels are assessed using conditional value at risk (CVaR). An important conclusion is that the results show that the greater the HPP risk aversion is, the greater the energy selling via electricity forward contracts. Moreover, the proposed model has benefits in comparison to a deterministic approach.
A Hybrid Grey Wolf Assisted-Sparrow Search Algorithm for Frequency Control of RE Integrated System
Authors: Fadheel Bashar Abbas , Wahab Noor Izzri Abdul , Mahdi Ali Jafer , Premkumar Manoharan , Radzi Mohd Amran Bin Mohd , Soh Azura Binti Che , Veerasamy Veerapandiyan , Irudayaraj Andrew Xavier Raj
Published: January 2023

Nowadays, renewable energy (RE) sources are heavily integrated into the power system due to the deregulation of the energy market along with environmental and economic benefits. The intermittent nature of RE and the stochastic behavior of loads create frequency aberrations in interconnected hybrid power systems (HPS). This paper attempts to develop an optimization technique to tune the controller optimally to regulate frequency. A hybrid Sparrow Search Algorithm-Grey Wolf Optimizer (SSAGWO) is proposed to optimize the gain values of the proportional integral derivative controller. The proposed algorithm helps to improve the original algorithms’ exploration and exploitation. The optimization technique is coded in MATLAB and applied for frequency regulation of a two-area HPS developed in Simulink. The efficacy of the proffered hybrid SSAGWO is first assessed on standard benchmark functions and then applied to the frequency control of the HPS model. The results obtained from the multi-area multi-source HPS demonstrate that the proposed hybrid SSAGWO optimized PID controller performs significantly by 53%, 60%, 20%, and 70% in terms of settling time, peak undershoot, control effort, and steady-state error values, respectively, than other state-of-the-art algorithms presented in the literature. The robustness of the proffered method is also evaluated under the random varying load, variation of HPS system parameters, and weather intermittency of RE resources in real-time conditions. Furthermore, the controller’s efficacy was also demonstrated by performing a sensitivity analysis of the proposed system with variations of 75% and 125% in the inertia constant and system loading, respectively, from the nominal values. The results show that the proposed technique damped out the transient oscillations with minimum settling time. Moreover, the stability of the system is analyzed in the frequency domain using Bode analysis.
Techno-Economic Evaluation of Future Thermionic Generators for Small-Scale Concentrated Solar Power Systems
Authors: Bellucci Alessandro , Caposciutti Gianluca , Antonelli Marco , Trucchi Daniele Maria
Published: January 2023

Small-size concentrated solar power (CSP) plants are presently not diffused due to a too-high levelized cost of electricity (LCoE), contrarily to CSP plants with capacity >100 MW, which provide LCoE < 20 cEUR/kWh. The integration of solid-state converters within CSP plants can enhance the scalability and economic competitiveness of the whole technology, especially at smaller scales, since the conversion efficiency of solid-state converters weakly depends on the size. Here a system with a high-temperature thermionic energy converter (TEC), together with an optical concentrator designed to be cheap even providing high concentration ratios, is proposed to improve the cost-effectiveness of CSP plants, thus achieving conditions for economic sustainability and market competitiveness. This is possible since TEC can act as a conversion topping cycle, directly producing electricity with a possible conversion efficiency of 24.8% estimated by applying realistic conditions and providing useful thermal flows to a secondary thermal stage. Under established technical specifications for the development of optical concentrator and TEC and according to reasonable economic assumptions, the overall plant conversion efficiency is estimated to be 35.5%, with LCoE of 6.9 cEUR/kW and considering the possibility of an 8 h storage tank for a 1 MW input solar energy system. The calculated projected value is an extremely competitive value compared with other available renewable energy technologies at small capacity scales and opens the path for accelerating the deployment of technological efforts to demonstrate the proposed solution.
Enhancement of Heavy-Duty Engines Performance and Reliability Using Cylinder Pressure Information
Authors: Brusa Alessandro , Corti Enrico , Rossi Alessandro , Moro Davide
Published: January 2023

Sustainability issues are becoming increasingly prominent in applications requiring the use of heavy-duty engines. Therefore, it is important to cut the emissions and costs of such engines to reduce the carbon footprint and keep the operating expenses under control. Even if for some applications a battery electric equipment is introduced, the diesel-equipped machinery is still popular thanks to the longer operating range. In this field, the open pit mines are a good example. In fact, the Total Cost of Ownership (TCO) of the mining equipment is highly impacted by fuel consumption (engine efficiency) and reliability (service interval and engine life). The present work is focused on efficiency enhancements achievable through the application of a combustion control strategy based on the in-cylinder pressure information. The benefits are mainly due to two factors. First, the negative effects of injectors aging can be compensated. Second, cylindrical online calibration of the control parameters enables the combustion system optimization. The article is divided into two parts. The first part describes the toolchain that is designed for the real-time application of the combustion control system, while the second part concerns the algorithm that would be implemented on the Engine Control Unit (ECU) to leverage the in-cylinder pressure information. The assessment of the potential benefits and feasibility of the combustion control algorithm is carried out in a Software in the Loop (SiL) environment, simulating both the developed control strategy and the engine behavior (Liebherr D98). Our goal is to validate the control algorithm through SiL simulations. The results of the validation process demonstrate the effectiveness of the control strategy: firstly, cylinder disparity on IMEP (+/−2.5% in reference conditions) is virtually canceled. Secondly, MFB50 is individually optimized, equalizing Pmax among the cylinders (+/−4% for the standard calibration) without exceeding the reliability threshold. In addition to this, BSFC is reduced by 1% thanks to the accurate cylinder-by-cylinder calibration. Finally, aging effects or fuel variations can be implicitly compensated, keeping optimal performance thorough the engine life.
Comparison of Measured and Derived Thermal Conductivities in the Unsaturated Soil Zone of a Large-Scale Geothermal Collector System (LSC)
Authors: Rammler Mario , Schwarz Hans , Wagner Jan , Bertermann David
Published: January 2023

The design, energetic performance, and thermal impact of large-scale geothermal collector systems (LSCs) are dependent on the thermal conductivity of unsaturated soils (λ). The aim of this study was to investigate the benefits of two different λ measurement methods using single-needle sensor measuring devices on a laboratory scale. Since large-scale determinations are required in the context of LSCs, the potential for deriving λ from electrical resistivity tomography measurements (ERTs) was also examined. Using two approaches—the continuous evaporation method and the punctual method—thermal conductivities of soil samples from Bad Nauheim (Germany) were measured. The results were compared with averaged λ derived from three ERT sections. With the evaporation method, significant bulk density changes were observed during the experimental procedure, which were caused by the clay content and the use of repacked samples. The punctual method ensures a sufficiently constant bulk density during the measurements, but only provides a small number of measurement points. The thermal conductivities derived from ERTs show largely minor deviations from the laboratory measurements on average. If further research confirms the results of this study, ERTs could provide a non-invasive and unelaborate thermal exploration of the subsurface in the context of large-scale infrastructure projects such as LSCs.
Biosurfactants as Multifunctional Remediation Agents of Environmental Pollutants Generated by the Petroleum Industry
Authors: Selva Filho Alexandre Augusto P. , Converti Attilio , Soares da Silva Rita de Cássia F. , Sarubbo Leonie A.
Published: January 2023

Fuel and oil spills during the exploration, refining, and distribution of oil and petrochemicals are primarily responsible for the accumulation of organic pollutants in the environment. The reduction in contamination caused by hydrocarbons, heavy metals, oily effluents, and particulate matter generated by industrial activities and the efficient recovery of oil at great depths in an environmentally friendly way pose a challenge, as recovery and cleaning processes require the direct application of surface-active agents, detergents, degreasers, or solvents, often generating other environmental problems due to the toxicity and accumulation of these substances. Thus, the application of natural surface-active agents is an attractive solution. Due to their amphipathic structures, microbial surfactants solubilize oil through the formation of small aggregates (micelles) that disperse in water, with numerous applications in the petroleum industry. Biosurfactants have proven their usefulness in solubilizing oil trapped in rock, which is a prerequisite for enhanced oil recovery (EOR). Biosurfactants are also important biotechnological agents in anti-corrosion processes, preventing incrustations and the formation of biofilms on metallic surfaces, and are used in formulations of emulsifiers/demulsifiers, facilitate the transport of heavy oil through pipelines, and have other innovative applications in the oil industry. The use of natural surfactants can reduce the generation of pollutants from the use of synthetic detergents or chemical solvents without sacrificing economic gains for the oil industry. Therefore, investments in biotechnological processes are essential. It is predicted that, in the not-too-distant future, natural surfactants will become viable from an economic standpoint and dominate the world market. The application of biosurfactants in these settings would lead to industrial growth and environmental sustainability. The main goal of this paper is to provide an overview of diverse applications of biosurfactants on environmental remediation, petroleum biotechnology, and the oil industry through a scientific literature review.
Renewable Energies and Sustainable Development: A Bibliometric Overview
Authors: García-Lillo Francisco , Sánchez-García Eduardo , Marco-Lajara Bartolomé , Seva-Larrosa Pedro
Published: January 2023

Sustainable development has positioned itself as a fundamental element of a transversal nature, being linked to the energy transition. In this sense, it must be included as a mainstream objective of all actions and strategies developed at the social, academic, business, and political levels. However, to the best of our knowledge, no bibliometric work has been carried out to date to analyze the main contributions to the literature focused on the concepts of renewable energy and sustainable development. The main aim of this paper is to establish the key trends and academic contributions made in the field of renewable energies and sustainable development. For this purpose, a bibliometric and co-citation analysis has been carried out using the Bibliometrix® tool, an open-source R package. The results show that this is a field of study that has significantly increased its importance in recent years, which is illustrated using different indicators. We conclude that research trends seem to be directed towards managing the transition to a new, more sustainable energy model composed of renewable energy production systems, in addition to the adoption of new technologies to increase the efficiency of products and power transmission systems. In this respect, the transition towards a new, more sustainable energy model seems to be a fundamental step to guarantee the sustainability of human action.
Financial Analysis of Household Photovoltaic Self-Consumption in the Context of the Vehicle-to-Home (V2H) in Portugal
Authors: Nagel Rafael G. , Pires Vitor Fernão , Silveira Jony L. , Cordeiro Armando , Foito Daniel
Published: January 2023

This paper focuses on the purpose to see if it is possible to increase the earnings associated to the installation of PV systems in people’s homes. In accordance with this, a different way of thinking was adopted, namely the investment in batteries to maximize the energy earnings. The main problem of this classical approach is that the investment in those batteries is important. In this way, a different perspective was taken into account, namely the use of the electrical vehicles. This kind of vehicles is starting to become a real reality. In fact, the selling of these vehicles start to become a solution for the ordinary people, and it is expected in a very near future to be a reality for most of them. Thus, this study presents the use of a storage system based on the vehicle-to-home (V2H) technology for the people’s homes. The V2H availability varies among prosumers profile regarding the daily routines, weather conditions, and business aspects, besides other aspects. These profiles were combined with different power panels with and without injection into the grid. The costs of each configuration considering a residential consumer located in Portugal, as well as, their peak solar hours in a year were estimated. From this study, it will be possible to verify that the obtained economical results show that the usage of V2H as storage system based on batteries for modern homes is very attractive.
A Numerical Analysis of the Hybrid Nanofluid (Ag+TiO2+Water) Flow in the Presence of Heat and Radiation Fluxes
Authors: Ullah Asad , Fatima Nahid , Alharbi Khalid Abdulkhaliq M. , Elattar Samia , Ikramullah Ikramullah , Khan Waris
Published: January 2023

The hydrothermal characteristics of (Ag+TiO2+H2O) hybrid nanofluid three dimensional flow between two vertical plates, in which the right permeable plate stretches as well as rotates, are investigated by employing varying magnetic, heat and radiation fluxes. The motion is governed by coupled PDEs (nonlinear) obeying suitable boundary conditions. The PDEs coupled system is transformed to a coupled set of nonlinear ODEs employing appropriate similarity transformation relations. The resultant equations are numerically solved through the bv4c solver. The impact of the changing strength of associated parameters on the flow is investigated graphically and through tables. It has been found that the velocity gradient and velocity initially increase and then decrease with increasing Grashof number values in both the suction and injection cases. The enhancing magnetic field first augments and then lowers the velocity gradient in the presence of radiation source of maximum strength. The increasing strength of injection parameter drops the velocity. The temperature distribution in the fluid increases with the increasing Eckert number, radiation flux and heat strength and nanomaterial concentration, and depreciates with the enhancing injection parameter values and Prandtl number. The Cfx increases with a higher magnetic field magnitude and nanomaterial concentration, and declines with an increasing Grashof number. The results obtained are compared with the available literature in the form of tables.
A Model Predictive Control Based Optimal Task Allocation among Multiple Energy Storage Systems for Secondary Frequency Regulation Service Provision
Authors: Wang Xiuli , Li Xudong , Ni Weidong , Wen Fushuan
Published: January 2023

Power system stability has been suffering increasing threats with the ever-growing penetration of intermittent renewable generation such as wind power and solar power. Battery energy storage systems (BESSs) could mitigate frequency fluctuation of the power system because of their accurate regulation capability and rapid response. By dividing the Area Control Error (ACE) signal and the State of Charge (SOC) of battery energy storage systems into different intervals, the frequency control task of BESSs could be determined by considering the frequency control demand of the power grid in each interval and SOC self-recovery. The well-developed model predictive control can be employed to attain the optimal control variable sequence of BESSs in the following time, which can determine the output depths of BESSs and action timing at different intervals. The simulation platform MATLAB/Simulink is used to build two secondary frequency control scenarios of BESSs for providing frequency regulation service. The feasibility of the presented strategy is demonstrated by simulation results of a sample system.
Sliding Mode Control for Single-Phase Grid-Connected Voltage Source Inverter with L and LCL Filters
Authors: de Brito Moacyr A. G. , Dourado Egon H. B. , Sampaio Leonardo P. , da Silva Sergio A. O. , Garcia Raymundo C.
Published: January 2023

This paper presents an analysis of the sliding mode control (SMC) method applied to a single-phase grid-connected voltage source inverter (VSI) with L and LCL filters. First, simulation results were presented for the L filter, and then, after some adjustments, the same theory was applied to the LCL VSI with active damping. To improve the obtained results for the SMC control, we adopted the hyperbolic tangent function and the explicit establishment of the modulation index m in the mathematical procedure to help reduce the chattering phenomena; later on, the same function was replaced by the usage of a proportional plus resonant controller to continuously improve the control system responses.
Online Process State Estimation for Hansenula polymorpha Cultivation with 2D Fluorescence Spectra-Based Chemometric Model Calibrated from a Theoretical Model in Place of Offline Measurements
Authors: Babor Majharulislam , Paquet-Durand Olivier , Berg Christoph , Büchs Jochen , Hitzmann Bernd
Published: January 2023

The use of 2D fluorescence spectra is a powerful, instantaneous, and highly accurate method to estimate the state of bioprocesses. The conventional approach for calibrating a chemometric model from raw spectra needs a large number of offline measurements from numerous runs, which is tedious, time-consuming, and error-prone. In addition, many process variables lack direct signal responses, which forces chemometric models to make predictions based on indirect responses. In order to predict glycerol and biomass concentrations online in batch cultivation of Hansenula polymorpha, this study substituted offline measurements with simulated values. The only data from cultivations needed to generate the chemometric model were the 2D fluorescence spectra, with the presumption that they contain sufficient information to characterize the process state at a measurement point. The remainder of the evaluation was carried out with the aid of a mathematical process model that describes the theoretical interferences between process variables in the system. It is shown that the process model parameters, including microbial growth rate, the yield of biomass from glycerol, and lag time can be determined from only the spectra by employing a model-based calibration (MBC) approach. The prediction errors for glycerol and biomass concentrations were 8.6% and 5.7%, respectively. An improved model-based calibration (IMBC) approach is presented that calibrates a chemometric model for only biomass. Biomass was predicted from a 2D fluorescence spectrum in new cultivations, and glycerol concentration was estimated from the process model utilizing predicted biomass as an input. By using this method, the prediction errors for glycerol and biomass were reduced to 5.2% and 4.7%, respectively. The findings indicate that model-based calibration, which can be carried out with only 2D fluorescence spectra gathered from prior runs, is an effective method for estimating the process state online.
Cellulose from Posidonia oceanica Sea Balls (Egagropili) as Substrate to Enhance Streptomyces roseochromogenes Cellulase Biosynthesis
Authors: Restaino Odile Francesca , Cuomo Sabrina , D’Ambrosio Sergio , Vassallo Valentina , Mirpoor Seyedeh Fatemeh , Giosafatto Concetta Valeria L. , Porta Raffaele , Schiraldi Chiara
Published: January 2023

Enhancing Streptomyces cellulase production by supplying lignocellulose biomasses has been poorly investigated so far. In this research the biosynthesis of Streptomyces roseochromogenes ATCC13400 cellulases was increased for the first time by addition of a cellulose fraction (2.5 g·L−1) to the growth medium, isolated from the marine origin Posidonia oceanica sea balls, generally called egagropili.. In shake flasks the cellulase production increased of 4.3 folds, compared to the control, up to 268 U·L−1 in 72 h, with a productivity of 3.7 U·L−1·h−1, while in batch it was further enhanced up to 347 U·L−1 in 45 h with a doubled productivity of 7.7 U·L−1·h−1 A downstream protocol was set up by coupling two ultrafiltration steps on 10 and 3 kDa membranes to recover the enzymes from the supernatant. A pool of three cellulases, having molecular weights between 115 and 47 kDa, was recovered. The optimal conditions for their enzymatic activity were 60 °C and pH 5.0, and they showed CMCase, FPase and β-glucosidase action. In conclusion, S. roseochromogenes might be considered a new cell factory for cellulase biotechnological production that might be enhanced by using the cellulose from egagropili, a well-known marine origin plant waste, as the substrate.
Effect of Corn Straw on Hydrogen Production from Lignite
Authors: Wang Ying , Ma Litong , Li Jun
Published: January 2023

The conversion of lignite to clean energy has won considerable attention and plays an important role in achieving the goal of carbon reduction. The effects of corn straw on hydrogen production from lignite was explored by using lignite as the substrate and corn straw as an exogenous substance. The fermentation mechanism was elucidated through the analysis of total and daily hydrogen production; the concentration of humic acid, benzoic acid, pyruvate, and glucose, as well as pH value. In addition, total solid (TS), and volatile solid (VS) from activated sludge before and after fermentation are examined. The results showed that corn straw could accelerate hydrogen production from lignite with an optimal content of corn straw of 40%. The fermentative hydrogen production with 40% corn straw was up to 186.20 mL, 3.40 times higher than that of the control group. Corn straw effectively improved the concentration of humic acid and benzoic acid, accelerating the anaerobic fermentation of lignite to produce hydrogen. The concentration of pyruvic acid, glucose, pH, and the changes in TS and VS before and after fermentation showed that the group of 40% corn straw had a better promotion effect than other systems for hydrogen production. This provides a new idea for improving hydrogen production through lignite anaerobic fermentation.
Effect of Moisture and Oil Content in the Supercritical CO2 Defatting of Hermetia illucens Larvae
Authors: Fornari Tiziana , Vázquez Luis , Villanueva-Bermejo David , Hurtado-Ribeira Raúl , Martín Hernández Diego , Martin Diana
Published: January 2023

The supercritical defatting of H. illucens was scaled up at 450 bar and 60 °C from a 270 cm3 extraction cell to a vessel five times larger. Then, eight different H. illucens larvae batches, with variable content of oil (16.80–29.17% w/w) and moisture (4.45–15.95% w/w) were defatted. The effect of these parameters on yield and oil composition was analyzed. The presence of moisture in the larvae batch, in the range of the values studied, had no negative effect on the oil recovery efficiency, which was mainly determined by the initial content of oil in the larvae samples. Furthermore, no differences were determined in the fatty acid profile of the oils recovered, which were rich in saturated fatty acids, mainly lauric acid (ca. 50% w/w). Minor lipids, such as squalene and phytosterols, were determined in all the oil samples. The moisture content in the oils extracted was in the range of 0.118–1.706% w/w. Therefore, some samples exceeded the limits recommended for volatile matter in edible fats and oils (0.2%, including moisture). Yet, concerning the oil peroxide index, values were much lower than those corresponding to the oil extracted using hexane.
High-Value Bioconversion of Ginseng Extracts in Betaine-Based Deep Eutectic Solvents for the Preparation of Deglycosylated Ginsenosides
Authors: Yang Wenhua , Gu Qiuya , Zhou Jianli , Liu Xiaobo , Yu Xiaobin
Published: January 2023

Deep eutectic solvents (DES), as a green alternative to traditional organic solvents in biocatalysis, not only activate proteins but even increase the efficiency of enzymatic reactions. Here, DES were used in a combinatorial enzyme-catalyzed system containing β-glucosidase BGLAt and β-galactosidase BGALAo to produce deglycosylated ginsenosides (De-g) from ginseng extracts (GE). The results showed that DES prepared with betaine and ethylene glycol (molar ratio, 1:2) could significantly stimulate the activity of the combinatorial enzymes as well as improve the acid resistance and temperature stability. The DES-based combinatorial enzyme-catalyzed system could convert 5 g of GE into 1.24 g of De-g (F1, F2, 20 (S)-PPT, and CK) at 24 h, which was 1.1 times that of the buffer sample. As confirmed by the spectral data, the changes in the conformations of the combinatorial enzymes were more favorable for the binding reaction with the substrates. Moreover, the constructed DES-based aqueous two-phase system enabled the recovery of substantial amounts of DES and De-g from the top phase. These results demonstrated that DES shows great application as a reaction solvent for the scale-up production of De-g and provide insights for the green extraction of natural products.
Development of Enriched Oil with Polyphenols Extracted from Olive Mill Wastewater
Authors: Athanasiadis Vassilis , Voulgaris Andreas , Katsoulis Konstantinos , Lalas Stavros I. , Roussis Ioannis G. , Gortzi Olga
Published: January 2023

The extraction of olive oil produces significant residual olive-mill wastewater (OMW). The composition of OMW varies according to the type of olive, the fruit’s ripeness level, and the extraction method (traditional one-pressing system or continuous systems based on centrifugation of the olive pulp). In olive-producing countries, OMW is important for the environment and the economy and is also a low-cost source of polyphenolic compounds with high antioxidant properties. Olive oil’s properties, such as its anti-atherogenic, anti-inflammatory, anti-aging, and immunological modulator effects, have been attributed to its polyphenols. In this study, the cloud point extraction (CPE) method was used to recover polyphenolic compounds from OMW. The total micellar phase of the three recoveries was 24.2% and the total polyphenols (after sonication) was 504 mg GAE/Kg. Furthermore, the addition of polyphenols recovered from OMW enhanced the olive oil and extended its shelf life without changing its organoleptic properties. There was a 42.2% change in polyphenols after 0.5% enrichment of micellar dispersions. Thus, it is suggested that the CPE method could lead to better waste management in the olive oil industry and improve the nutritional quality of food products.
Soy Protein Isolate as Emulsifier of Nanoemulsified Beverages: Rheological and Physical Evaluation
Authors: Castro-Criado Daniel , Jiménez-Rosado Mercedes , Perez-Puyana Víctor , Romero Alberto
Published: January 2023

The production of biologically active molecules or the addition of new bioactive ingredients in foods, thereby producing functional foods, has been improved with nanoemulsion technology. In this sense, the aim of this work was to develop nanoemulsified beverages as potential candidates for the encapsulation of bioactive compounds, whose integrity and release across the intestinal tract are controlled by the structure and stability of the interfaces. To achieve this, firstly, a by-product rich-in protein has been evaluated as a potential candidate to act as an emulsifier (chemical content, amino acid composition, solubility, ζ-potential and surface tension were evaluated). Later, emulsions with different soy protein isolate concentrations (0.5, 1.0, 1.5 and 2.0 wt%), pH values (2, 4, 6 and 8) and homogenization pressures (100, 120 and 140 PSI) were prepared using a high-pressure homogenizer after a pre-emulsion formation. Physical (stability via Backscattering and drop size evolution) and rheological (including interfacial analysis) characterizations of emulsions were carried out to characterize their potential as delivery emulsion systems. According to the results obtained, the nanoemulsions showed the best stability when the protein concentration was 2.0 wt%, pH 2.0 and 120 PSI was applied as homogenization pressure.
Machine Learning Algorithms Applied to Semi-Quantitative Data of the Volatilome of Citrus and Other Nectar Honeys with the Use of HS-SPME/GC–MS Analysis, Lead to a New Index of Geographical Origin Authentication
Authors: Karabagias Ioannis Konstantinos , Nayik Gulzar Ahmad
Published: January 2023

The scope of the current study was to monitor if semi-quantitative data of volatile compounds (volatilome) of citrus honey (ch) produced in different countries could potentially lead to a new index of citrus honey authentication using specific ratios of the identified volatile compounds in combination with machine learning algorithms. In this context, the semi-quantitative data of the volatilome of 38 citrus honey samples from Egypt, Morocco, Greece, and Spain (determined by headspace solid phase microextraction coupled to gas chromatography mass spectrometry (HS-SPME/GC–MS)) was subjected to supervised and unsupervised chemometrics. Results showed that honey samples could be classified according to the geographical origin based on specific volatile compounds. Data were further evaluated with additional nectar honey samples introduced in the multivariate statistical analysis model and the classification results were not affected. Specific volatile compounds contributed to the discrimination of citrus honey in different amounts according to geographical origin. These were lilac aldehyde D, dill ether, 2-methylbutanal, heptane, benzaldehyde, α,4-dimethyl-3-cyclohexene-1-acetaldehyde, and herboxide (isomer II). The numerical data of these volatile compounds was summed up and divided by the total semi-quantitative volatile content (Rch, Karabagias–Nayik index) of citrus honey, according to geographical origin. Egyptian citrus honey had a value of Rch = 0.35, Moroccan citrus honey had a value of Rch = 0.29, Greek citrus honey had a value of Rch = 0.04, and Spanish citrus honey had a value of Rch = 0.27, leading to a new hypothesis and a complementary index for the control of citrus honey authentication.
Advances in Environmentally Friendly Techniques and Circular Economy Approaches for Insect Infestation Management in Stored Rice Grains
Authors: de Sousa Inês Gonçalves , Oliveira Jorge , Mexia António , Barros Graça , Almeida Carina , Brazinha Carla , Vega Anna , Brites Carla
Published: January 2023

Rice (Oryza sativa L.) is a staple food for about half of the world’s population. Therefore, it is important to search for solutions that minimise losses and production costs for producers and ensure food quality and safety for consumers. Improved methods for the detection and monitoring of hidden infestations are useful for adopting infestation control measures. Chemical methods are used to prevent rice losses due to infestations; changing this situation, however, is of the utmost importance, as it harms the environment and human health. The management of infestation by controlled storage conditions, namely temperature and atmosphere composition and the use of current fossil-based packaging with modified atmospheres, is well recognised. The use of environmentally friendly solutions is promising, but it is necessary to perform a life-cycle assessment and cost analysis to evaluate their effectiveness. According to the principles of circular economy, the integration of the best-selected treatments/solutions for insect management, along with the use of biopackaging from rice by-products are recommended. This review describes the methods of detection and control of infestation as well as several promising alternatives to chemical treatments; however, more research is needed in order to obtain effective technological solutions that can be applied at an industrial scale.
A Comprehensive Study on Antibiotic Resistance among Coagulase-Negative Staphylococci (CoNS) Strains Isolated from Ready-to-Eat Food Served in Bars and Restaurants
Authors: Chajęcka-Wierzchowska Wioleta , Gajewska Joanna , Zadernowska Anna , Randazzo Cinzia Lucia , Caggia Cinzia
Published: January 2023

The present study aimed to characterize and assess the diversity of CoNS strains as potential vectors for the spread of resistance to antimicrobial agents from RTE foods served in bars and restaurants. Eighty-five CoNS strains, obtained from 198 RTE food samples, were investigated. Sixty-seven CoNS isolates (78.8%) were resistant to at least one antibiotic tested, and 37 (43.5%) were multidrug resistant (MDR-CoNS). Moreover, CoNS strains contained genes conferring resistance to antibiotics critically important in medicine, i.e., β—lactams [mecA (29.4%); blaZ (84.7%)], aminoglycosides [aac(6′)-Ie-aph(2″)-Ia (45.9%); aph(2″)-Ic (3.5%)], macrolides, lincosamides and streptogramin B-MLSB [msrA/B (68.2%); ermB (40%) and mphC (4.7%)], tetracyclines [tetK (31.8%); tetM (16.5%) and/or tetL (2.35%)]. We also found the fusB/C/D genes responsible for the acquired low-level fusidic acid resistance (17.6%) and streptogramin resistance determinant vgaA in 30.6% of isolates. In three linezolid resistant strains (2 S. epidermidis and 1 S. warneri), mutation was detected, as demonstrated by L101V and V188I changes in the L3 protein amino acid sequences. The high frequency in RTE food of MDR-CoNS including methicillin-resistant (MR-CoNS) strains constitutes a direct risk to public health as they increase the gene pool from which pathogenic bacteria can pick up resistance traits.