bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytochemical, Antimicrobial, and Antioxidant Activity of Different Extracts from Frozen, Freeze-Dried, and Oven-Dried Jostaberries Grown in Moldova
Authors: Bulgaru Viorica , Gurev Angela , Baerle Alexei , Dragancea Veronica , Balan Greta , Cojocari Daniela , Sturza Rodica , Soran Maria-Loredana , Ghendov-Mosanu Aliona
Published: July 2024

In this paper, the qualitative and quantitative profile is evaluated of the bioactive compounds, antioxidant activity (AA), microbiostatic properties, as well as the color parameters of jostaberry extracts, obtained from frozen (FJ), freeze-dried (FDJ), and oven-dried berries (DJ). The optimal extraction conditions by ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) were selected after determination of the total polyphenol content (TPC), total flavonoid content (TFC), total antocyanin content (TA), AA by 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH), and the free radical cation 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonates (ABTS). Non-conventional extraction methods are less destructive to anthocyanins, while drying the berries reduced TA, regardless of the extraction method. The oven-drying process reduced the concentration of TA in DJ extracts by 99.4% and of ascorbic acid by 92.42% compared to FJ. AA was influenced by the jostaberry pretreatment methods. The DPPH and ABTS tests recorded values (mg Trolox equivalent/g dry weight) between 17.60 and 35.26 and 35.64 and 109.17 for FJ extracts, between 7.50 and 7.96 and 45.73 and 82.22 for FDJ, as well as between 6.31 and 7.40 and 34.04 and 52.20 for DJ, respectively. The jostaberry pretreatment produced significant changes in all color parameters. Mutual information analysis, applied to determine the influence of ultrasound and microwave durations on TPC, TFC, TA, AA, pH, and color parameters in jostaberry extracts, showed the greatest influence on TA (0.367 bits) and TFC (0.329 bits). The DPPH and ABTS inhibition capacity of all FJ’ extracts had higher values and varied more strongly, depending on pH, heat treatment, and storage time, compared to the AA values of FDJ’ and DJ’ extracts. A significant antimicrobial effect was observed on all bacterial strains studied for FJP. FDJP was more active on Bacillus cereus, Staphylococcus aureus, and Escherichia coli. DJP was more active on Salmonella Abony and Pseudomonas aeruginosa. The antifungal effect of DJP was stronger compared to FDJP. Jostaberry extracts obtained under different conditions can be used in food production, offering a wide spectrum of red hues.
Investigation on Properties of Pervious Concrete Containing Co-Sintering Lightweight Aggregate from Dredged Sediment and Rice Husks
Authors: Rong Hao , Yue Kedong , He Yuting , Hu Zhen , Wang Rui , Huang Shuangshuang , Zhou Xian , Wang Teng
Published: July 2024

The utilization of dredged sediment (DS) as a transformative material in building applications presents an ideal consumption strategy. This study endeavors to create a novel ceramsite lightweight aggregate (LWA) through the co-sintering of DS and rice husks (RHs), further integrating this LWA into the construction of pervious concrete. Results revealed that the optimum production procedure for the DS-based LWA incorporated a 21% RH addition, a sintering temperature of 1100 °C, and a sintering duration of 21 min. Notably, the optimal ceramsite LWA, denoted as SDC-H, exhibited a cylinder compressive strength of 28.02 MPa and an adsorption efficiency for Pb2+ of 94.33%. Comprehensive analysis (encompassing bulk density, cylinder compressive strength, water absorption, and the leaching concentrations of heavy metals) confirmed that SDC-H impacted the specification threshold of high-strength light aggregate derived from solid waste (T/CSTM 00548-2022). Substituting 50% of SDC-H led to a diminution in the mechanical properties but an improvement in the dynamic adsorption capacity of the innovative pervious concrete, registering a mechanical strength of 26.25 MPa and a cumulative adsorption capacity for Pb2+ of 285 mg/g. These performances of pervious concrete containing 50% SDC-H might correlate with the evolution of an interconnected and open-pore structure.
Experimental Study on Mechanic Behavior of Flange Joint for Steel Tube Under Axial Tension
Authors: Si Jinyan , Liu Wei , Zhu Li , Zhu Yaoyu , Zhao Guanyuan , Hong Jian , Zhang Chenmin
Published: July 2024

The flange joint is an important connection in steel tube structures. In this paper, 11 groups of flange joint tests were conducted to investigate the influences of tube diameter, flange plate thickness, the distance from the bolt to the tube centroid, bolt numbers and material strength on the mechanical behavior. One of two failure modes in tests is that the excessive plastic deformation on the flange plate makes the flange plate lose the bearing capacity; the other is that the steel tube yield makes the joints fail. The results show that the calculating method for flange joint in Chinese design code is so safe that amplifying the calculating results of the code by 1.2 times would be closer to the bearing capacity of specimens. For a flange joint with different tube diameters, thickening the flange plate of thinner tube or thinning the flange plate of another tube are effective to ensure the deformations on both sides of the flange plates are equivalent. The ratio of the bearing capacity of the steel tube to that of flange plate should be greater than 1.7. And the thickness of the flange plate should be thicker than 14mm to reduce the deformation caused by cutting, drilling and welding during manufacturing.
Unveiling the Impact of Transportation Infrastructure Construction on Rurality: A Case Study from Guangdong, China
Authors: Zhang Shuaibing , Ma Wei , Wu Fengqi , Zhao Kaixu
Published: July 2024

Rurality is an important indicator to reflect the development of villages and reveal internal differences in rural areas. The unbalanced development of transportation infrastructure in the current period of rapid urbanization has become one of the principal elements triggering spatial differences in rurality and changes in rural territorial characteristics. However, there are few studies on the impact of transportation infrastructure accessibility on the multidimensional characteristics of rurality from the perspective of heterogeneity. This paper analyzed the spatio-temporal characteristics of transport accessibility (TA) and the county rurality index (CRI) in Guangdong in 2005, 2010, 2015 and 2020 using an accessibility model and the rurality index and explored the clustering characteristics and interactions of TA and the CRI through exploratory spatial data analysis (ESDA) and geographic weighted regression (GWR) modeling. The findings showed that (1) TA and the CRI in Guangdong were significantly unbalanced in terms of space. The CRI showed a weakening trend in general, forming a distribution pattern of “high in the north and low in the south, high in the west and low in the east”, while TA was on the rise, maintaining a stable pattern of “high in the middle and low in the periphery”. (2) Both TA and the CRI in Guangdong had a Moran’s I value greater than 0.6 during the study period, exhibiting strong spatial agglomeration, while the two showed a significant spatial negative correlation. (3) The influence of TA on the CRI in different dimensions showed dynamic changes in stages, with TA having a higher intensity of effect on society rurality and land rurality in 2005, while on society rurality and industry rurality in 2020. (4) This paper grouped 77 counties in Guangdong into four types of policy zonings—coordination types, lagged types of accessibility, lagged types of rurality and double lagged types—and put forward corresponding development recommendations. The study conducted in this paper contributes to an in-depth understanding of the impact of transportation infrastructure development on the multidimensional characteristics of rurality and provides a basis for policy formulation for coordinated urban–rural development and sustainable rural development.
Experimental Study on the Impact Resistance Performance of Civil Air Defense RC Walls Protected by Honeycomb Sandwich Panels
Authors: Yang Ran , Qu Dayi , Zhang Jigang
Published: July 2024

Reinforced concrete (RC) walls are extensively used in civil air defense engineering and are susceptible to low-speed impacts with high energy and massive weight during service. Therefore, it is crucial to consider the impact resistance of these walls and explore effective protection methods. The honeycomb structure, known for its energy-absorbing properties, has been widely utilized in aerospace, automotive, and maritime industries. However, there is a need for more research on applying honeycomb structures in energy-absorbing protection devices in civil engineering. This study proposes the use of honeycomb sandwich panels to protect civil air defense RC walls, creating a Honeycomb Sandwich Panel Composite RC wall (HSP-RC wall). Through pendulum impact experiments, we investigated the dynamic response of RC walls, both standard and HSP-RC walls with varying honeycomb parameters, under high-energy impacts. The goal was to evaluate the impact resistance of these RC walls, analyze the deformation differences among different HSP-RC walls, and examine the influence of honeycomb parameters on the impact protection effectiveness. The research results indicate that honeycomb sandwich panels can provide impact protection for RC walls by absorbing energy, and their protection effect is related to the parameters of the honeycomb core layer. This research result can be applied to RC structures that bear impact loads, achieving effective protection for RC structures.
A Comparative Study to Assess the Energy Efficiency of Temporary Structures to Guarantee Emergency Basic Healthcare in Italy
Authors: Brunoro Silvia , Mensi Lisa
Published: July 2024

During emergencies, healthcare is generally provided by tents and temporary shelters, without considering the environmental and social impact of the structures as a priority, in favor of swift response. The resultant constructions intended as a temporary solution often persist for a long time. This paper aims to analyze an alternative and innovative modular structure designed as a transitory solution in emergencies and everyday life. The aim of this study is to assess and compare the energetic performance of a modular adaptive model for basic healthcare for people who are not subscribed to the Italian National Health System. The main goal is to challenge standard models by proposing a new model able to diminish the weaknesses of the current sanitary models, to improve the social conditions, flexibility and energy efficiency, and the thermal comfort of the occupants. In the first part of the paper, the conceptual framework and the preliminary design of the model are described by investigating the benefits of a safe space as a generator space for care services and the community. In the second part, the technological requirements of the system are defined by comparing the use of different panel structures and low-impact technologies. The energy efficiency and environmental impact of the model are assessed by comparing several panel structures in two different climatic areas in Italy (northern and Mediterranean areas) using SketchUp and EnergyPlus simulation. As a result, different configurations of the model are proposed according to the different climatic areas in order to optimize the model, from both an architectural and a technological point of view (box and panel composition).
Immobilization of Laccase in β-Cyclodextrin Composite Hydrogel for Efficient Degradation of Dye Pollutants
Authors: Zhang Hong , Wang Zhi , Li Fengxi , Wang Lei , Ren Bo
Published: July 2024

A stable and efficient biocatalyst was prepared by encapsulating Trametes versicolor laccase using an acrylic acid-grafted β-cyclodextrin hydrogel (Lac-CD-PAA). Scanning electron microscopy and nitrogen adsorption-desorption experiments showed that there were regularly distributed channels in the spongy Lac-CD-PAA. In addition, a large number of mesopores and macropores existed in the wall of the hydrogel lamellae. This network structure reduced the diffusion resistance of the hydrogel to the target substrate. The relative activity of the resulting Lac-CD-PAA could be maintained at 35.8% after six cycles of use. Lac-CD-PAA exhibited higher thermal and chemical stability compared to free laccase. The negative charge on the surface of Lac-CD-PAA gives it the ability to pretreat cationic dyes. In six consecutive methylene blue decolorization tests, Lac-CD-PAA decolorized better than free laccase. The results showed that the prepared β-cyclodextrin-based composite hydrogel was a good carrier for laccase.
Synthetic mRNAs Containing Minimalistic Untranslated Regions Are Highly Functional In Vitro and In Vivo
Authors: Mamaghani Shahab , Penna Rocco Roberto , Frei Julia , Wyss Conrad , Mellett Mark , Look Thomas , Weiss Tobias , Guenova Emmanuella , Kündig Thomas M. , Lauchli Severin , Pascolo Steve
Published: July 2024

Synthetic mRNA produced by in vitro transcription (ivt mRNA) is the active pharmaceutical ingredient of approved anti-COVID-19 vaccines and of many drugs under development. Such synthetic mRNA typically contains several hundred bases of non-coding “untranslated” regions (UTRs) that are involved in the stabilization and translation of the mRNA. However, UTRs are often complex structures, which may complicate the entire production process. To eliminate this obstacle, we managed to reduce the total amount of nucleotides in the UTRs to only four bases. In this way, we generate minimal ivt mRNA (“minRNA”), which is less complex than the usual optimized ivt mRNAs that are contained, for example, in approved vaccines. We have compared the efficacy of minRNA to common augmented mRNAs (with UTRs of globin genes or those included in licensed vaccines) in vivo and in vitro and could demonstrate equivalent functionalities. Our minimal mRNA design will facilitate the further development and implementation of ivt mRNA-based vaccines and therapies.
Identification of Pathogenic Pathways for Recurrence of Focal Segmental Glomerulosclerosis after Kidney Transplantation
Authors: Pajenda Sahra , Gerges Daniela , Wagner Ludwig , O’Connell David , Aiad Monika , Imre Richard , Mechtler Karl , Zimprich Alexander , Schmidt Alice , Sengoelge Guerkan , Winnicki Wolfgang
Published: July 2024

Primary focal segmental glomerulosclerosis (FSGS) is a disease of the podocytes and glomerulus, leading to nephrotic syndrome and progressive loss of renal function. One of the most serious aspects is its recurrence of disease in over 30% of patients following allogeneic kidney transplantation, leading to early graft loss. This research investigates the individual genetic predispositions and differences in the immune responses leading to recurrence of FSGS after transplantation. We performed exome sequencing on six patients with recurrent FSGS to identify variants in fifty-one genes and found significant variations in the alpha-2-macroglobulin (A2M). Immunoblotting was used to investigate effects of specific gene variants at the protein level. Further expression analysis identified A2M, exophilin 5 (EXPH5) and plectin (PLEC) as specific proteins linked to podocytes, endothelial cells, and the glomerulus. Subsequent protein array screening revealed the presence of non-HLA-specific antibodies, including TRIM21, after transplantation. Using Metascape for pathway and process enrichment analysis, we focused on the IL-17 signaling and chemotaxis pathways. ELISA measurements showed significantly elevated IL-17 levels in patients with recurrent FSGS (32.30 ± 9.12 pg/mL) compared to individuals with other glomerular diseases (23.16 ± 2.49 pg/mL; p < 0.01) and healthy subjects (22.28 ± 0.94 pg/mL; p < 0.01), with no significant difference in plasma CCL2/MCP-1 levels between groups. This study explores the molecular dynamics underlying recurrence of FSGS after transplantation, offering insights into potential biomarkers and therapeutic targets for the future development of individualized treatments for transplant patients.
Early Presentation of Boerhaave Syndrome in the Emergency Department: A Case Report and Review of the Literature
Authors: Eremia Irina-Anca , Anghel Cătălin-Alexandru , Cofaru Florina-Alexandra , Nica Silvia
Published: July 2024

We present the case of a 46-year-old patient who arrived at the emergency department with chest pain following an episode of vomiting. The diagnosis was Boerhaave syndrome and acute mediastinitis. Due to the prompt presentation and the location of the rupture in the lower esophagus, emergency surgical intervention was performed, including esophageal suturing, mediastinal drainage, and jejunostomy for feeding. Postoperatively, the patient was transferred to the intensive care unit for advanced monitoring and support. The patient’s condition improved favorably in the intensive care unit, allowing for extubation. Progress continued positively, and the patient was discharged 12 days postoperatively with a functional jejunostomy. At regular follow-ups, the patient’s recovery remained favorable, and the jejunostomy was removed 30 days after the surgery. This case highlights the importance of rapid diagnosis and early surgical intervention in Boerhaave syndrome, demonstrating the successful management of a severe condition through a multidisciplinary effort.
An Interdisciplinary Approach: Presentation of the Pediatric Obstructive Sleep Apnea Diagnostic Examination Form (POSADEF)
Authors: Sambale Janine , Birk Richard , Koehler Ulrich , Hildebrandt Wulf , Korbmacher-Steiner Heike Maria
Published: July 2024

This report emphasizes the need for interdisciplinary collaboration in diagnosing and treating pediatric obstructive sleep apnea (OSA). OSA, affecting 1% to 4% of children, often results from adenotonsillar hypertrophy, craniofacial disorders, or obesity. While adenotonsillectomy is the primary treatment, about 75% of children, especially those with craniofacial disorders or obesity, continue to experience OSA symptoms post-surgery. To address these cases, several medical fields emphasize the necessity and demand for interdisciplinary collaboration in managing pediatric OSA. Therefore, the authors aimed to develop the Pediatric Obstructive Sleep Apnea Diagnostic Examination Form (POSADEF). This form, based on clinical experience and the literature, captures craniofacial and functional characteristics linked to pediatric OSA. A case study of an eight-year-old girl with OSA, who was unsuccessfully treated with adenotonsillectomy, underlines the importance of the diagnostic examination form. The orthodontic assessment revealed craniofacial disorders and subsequent treatment with maxillary expansion and functional appliance therapy resolved her OSA symptoms. This case demonstrates the value of POSADEF in enabling comprehensive evaluation and treatment across medical disciplines. POSADEF is designed to assist health care professionals in diagnosing craniofacial and orofacial anomalies contributing to pediatric OSA.
An Active Inference Agent for Modeling Human Translation Processes
Authors: Carl Michael
Published: July 2024

This paper develops an outline for a hierarchically embedded architecture of an artificial agent that models human translation processes based on principles of active inference (AIF) and predictive processing (PP). AIF and PP posit that the mind constructs a model of the environment which guides behavior by continually generating and integrating predictions and sensory input. The proposed model of the translation agent consists of three processing strata: a sensorimotor layer, a cognitive layer, and a phenomenal layer. Each layer consists of a network of states and transitions that interact on different time scales. Following the AIF framework, states are conditioned on observations which may originate from the environment and/or the embedded processing layer, while transitions between states are conditioned on actions that implement plans to optimize goal-oriented behavior. The AIF agent aims at simulating the variation in translational behavior under various conditions and to facilitate investigating the underlying mental mechanisms. It provides a novel framework for generating and testing new hypotheses of the translating mind.
Molecular-Scale Liquid Density Fluctuations and Cavity Thermodynamics
Authors: Tortorella Attila , Graziano Giuseppe
Published: July 2024

Equilibrium density fluctuations at the molecular level produce cavities in a liquid and can be analyzed to shed light on the statistics of the number of molecules occupying observation volumes of increasing radius. An information theory approach led to the conclusion that these probabilities should follow a Gaussian distribution. Computer simulations confirmed this prediction across various liquid models if the size of the observation volume is not large. The reversible work required to create a cavity and the chance of finding no molecules in a fixed observation volume are directly correlated. The Gaussian formula for the latter probability is scrutinized to derive the changes in enthalpy and entropy, which arise from the cavity creation. The reversible work of cavity creation has a purely entropic origin as a consequence of the solvent-excluded volume effect produced by the inaccessibility of a region of the configurational space. The consequent structural reorganization leads to a perfect compensation of enthalpy and entropy changes. Such results are coherent with those obtained from Lee in his direct statistical mechanical study.
Making the Thermodynamic Cost of Active Inference Explicit
Authors: Fields Chris , Goldstein Adam , Sandved-Smith Lars
Published: July 2024

When describing Active Inference Agents (AIAs), the term “energy” can have two distinct meanings. One is the energy that is utilized by the AIA (e.g., electrical energy or chemical energy). The second meaning is so-called Variational Free Energy (VFE), a statistical quantity which provides an upper bound on surprisal. In this paper, we develop an account of the former quantity—the Thermodynamic Free Energy (TFE)—and its relationship with the latter. We highlight the necessary tradeoffs between these two in a generic, quantum information-theoretic formulation, and the macroscopic consequences of those tradeoffs for the ways that organisms approach their environments. By making this tradeoff explicit, we provide a theoretical basis for the different metabolic strategies that organisms from plants to predators use to survive.
Teacher Performance Level to Guide Students in Inquiry-Based Scientific Learning
Authors: Talavera-Mendoza Fabiola , Cayani Caceres Karina Sandra , Urdanivia Alarcon Diego Antonio , Gutiérrez Miranda Sonia Amparo , Rucano Paucar Fabian Hugo
Published: July 2024

The strategies employed by teachers and students in the open inquiry-based learning approach are crucial, especially when presenting researchable questions formulated by students under the guidance of the teacher. This effectively promotes the teaching and learning of various disciplines. Participant observation was conducted in the science classroom for secondary education teachers to establish the level achieved by teachers in the development of the open inquiry-based learning experience and to identify the taxonomic level of researchable questions (RQs). An observation rubric was applied, revealing that 83% of in-service teachers reached a satisfactory level, while 67% of pre-service teachers were classified as unsatisfactory in terms of using the open inquiry-based approach. Both groups formulated high-order inquiry questions, with a clear inclination in favor of in-service teachers compared to pre-service teachers. These results highlight the importance of university training in focusing on inquiry skills, particularly in planning, inferences, and evaluation. Through this observational analysis, valuable information about the current state of open inquiry-based learning is contributed, advancing science education in Peru.
Teacher-Directed to Student-Engaged Pedagogy: Exploring Teacher Change
Authors: Schultz Robert A.
Published: July 2024

An under-explored issue in teacher education is the active documentation of pedagogical usage after initial training and practice implementation have been completed. In this phenomenological study, the researcher contacted previous graduate students who earned a teaching-endorsement credential for working with Gifted/Talented learners to explore the application of a pedagogical method developed specifically to shift from teacher-directed to student-engaged pedagogy. Common impediments to pedagogical change are described and discussed. Participants did overcome impediments, changing their pedagogical approach from teacher-directed to student-engaged approaches over time. Each shared their particular circumstances for needing to change their teaching approach. But in all instances, student performance and outcomes drove and supported the continued expansion of the change process. Future empirical work in teacher development and in-service pedagogical change based on results is suggested to further this line of inquiry.
Analysis of Cooling Technologies in the Data Center Sector on the Basis of Patent Applications
Authors: Ott Benjamin , Wenzel Paula M. , Radgen Peter
Published: July 2024

The cooling of server components has been developed over the past few years in order to meet increasing cooling requirements. The growth in performance and power density increases the cooling demand. To gain a better understanding of the evolution and possible future technology developments in the field of data center cooling, a patent analysis method was used with a focus on the server and computer room levels. After the patent extraction from the European patent database for the period 2000–2023, the search results were classified and analyzed. Most of the patents deal with air or liquid cooling. Since 2015, a technological shift from air to liquid cooling can be identified on the level of patent activities. In conclusion, from the patent analysis, it can be derived that liquid cooling will continue to gain in importance in the future and could also be combined with other approaches in the form of hybrid cooling. However, air cooling may still be relevant, even if the main cooling load is handled by liquid-based approaches. At the same time, the optimization potential for air cooling seems to have been largely exploited in comparison to liquid cooling, as can be seen from the falling number of the patent applications.
Numerical Investigation on the Effects of Gap Circulating Flow on Blower Performance under Design and Off-Design Conditions
Authors: Zhang Xu , Gong Yuxiang , Chen Xiaochang , Hu Liang , Xie Haibo , Yang Huayong
Published: July 2024

Blowers are widely used in tasks such as ventilation, exhaust, drying, cooling, heat dissipation, or conveying medium, and they usually consume a lot of energy. There is an inevitable gap between the rotating impeller and static volute casing due to manufacturing tolerance and thermal deformation. The circulating flow in the gap has an important effect on the performance of the blower. In this study, computational fluid dynamics (CFD) was used to investigate the performance of the blower under different flow conditions and gaps, and the accuracy of the numerical simulation was verified by performance experiments. The results show that the flow separation under low flow conditions in the impeller channel can be suppressed by the circulating flow. However, the efficiency of the blower is decreased because a part of the power is used to maintain the circulating flow. Under design conditions, efficiency is reduced by 5.3~8.2%, depending on the gap sizes. Due to the increased flow rate in the impeller channel caused by the gap circulating flow, the net flow rate of the impeller under design conditions is about 12% higher than the inlet flow rate of the blower. Therefore, it leads to an increase of about 12% in impeller efficiency calculated by the net flow rate compared with the inlet flow rate. Finally, the flow field distribution on the impeller channel under different gap conditions was compared, and the effects of the gap on the blower performance were analyzed from the perspective of flow field structure.
Optimal Resilience and Risk-Driven Strategies for Pre-Disaster Protection of Electric Power Systems against Uncertain Disaster Scenarios
Authors: Wang Chen , Zhang Chao , Luo Ling , Qi Xiaoman , Kong Jingjing
Published: July 2024

Pre-disaster protection strategies are essential for enhancing the resilience of electric power systems against natural disasters. Considering the budgets for protection strategies, the dependency of other infrastructure systems on electricity, and the uncertainty of disaster scenarios, this paper develops risk-neutral and risk management models of strategies for pre-disaster protection. The risk-neutral model is a stochastic model designed to maximize the expected value of resilience (EVR) of the integrated system. The risk management model is a multi-objective model prioritizing the minimization of risk metrics as a secondary goal alongside maximizing the EVR. A case study conducted on the energy infrastructure systems in the Greater Toronto Area (GTA) validates the effectiveness of the models. The findings reveal the following: (i) increasing the budget enhances the EVR of the integrated system; however, beyond a certain budget threshold, the incremental benefits to the EVR significantly diminish; (ii) reducing the value of the downside risk often results in an increase in the EVR, with the variation in Pareto-optimal solutions between the two objectives being non-linear; and (iii) whether for the risk-neutral or risk management protection strategies, there are reasonable budgets when considering disaster intensity and the cost of protection measures. The models can help decision-makers to select effective protection measures for natural disasters.
A Hybrid Energy System Based on Externally Fired Micro Gas Turbines, Waste Heat Recovery and Gasification Systems: An Energetic and Exergetic Performance Analysis
Authors: Reale Fabrizio , Massoli Patrizio
Published: July 2024

The opportunities related to the adoption of synthetic gaseous fuels derived from solid biomass are limited by the issues caused by the peculiarities of the syngas. The aim of this paper is to analyze several possible layouts of hybrid energy systems, in which the main thermal source is the organic fraction of municipal solid wastes. The case of a small community of about 1000 persons is analyzed in this paper. The examined layouts coupled an externally fired micro gas turbine with a waste heat recovery system based on both an Organic Rankine Cycle and supercritical CO2 gas turbines. A thermodynamic analysis has been carried out through the use of the commercial software Thermoflex 31, considering the losses of each component and the non-ideal behavior of the fluids. The results of the numerical analysis highlight that the introduction of a waste heat recovery system leads to an increase of at least 16% in the available net power, while a cascade hybrid energy grid can lead to a power enhancement of about 29%, with a considerable increase also in the energetic and exergetic global efficiencies.
Investigation of Removing Asphaltene-Resin-Paraffin Deposits by Chemical Method for Azerbaijan High-Paraffin Oil Production Process
Authors: Wang Xiuyu , Gurbanov Huseyn , Adygezalova Mehpara , Alizade Elnur
Published: July 2024

Asphaltene-resin-paraffin deposition (ARPD) is a complicated and prevalent issue in the oil and gas industry, impacting the efficiency and integrity of petroleum extraction, production, transportation and processing systems. Considering all witnessed ARPD problems in Azerbaijan oil fields, this paper proposed a chemical method and optimized the type and concentration of chemical inhibitors. Then, the effect of selected chemical reagents on inhibiting the ARPD amount and thus enhancing oil recovery was detected by reservoir simulation during both waterflooding and CO2 flooding production. Three new chemical compounds (namely, Chemical-A, Chemical-B and Chemical-C) were examined in laboratory conditions, and their impact on rheological properties of high-paraffin oilfield samples of Azerbaijan (X, Y and Z) were investigated. Experimental results show that Chemical-C with a concentration of 600 g/t has the best efficiency for alleviating the problems. After adding Chemical-C to the crude oil, the freezing point of oil was decreased from 12 °C to (−4) °C, the ARPD amount declined from 0.185 to 0.016 g, and oil effective viscosity was reduced from 16.2 mPa·s to 3.1 mPa·s. It was determined that for water and CO2 flooding, higher injection pressure resulted in reduced asphaltene precipitation. Adding the selected ARPD inhibitor, the oil recovery for waterflooding can increase from 52% to 62%, while it can rise from 55% to 68% for CO2 flooding.
Impact of Renewable Energy, Business Climate, and Human Capital on CO2 Emissions: Empirical Evidence from BRICS Countries
Authors: Sezgin Funda H. , Bayar Yilmaz , Sart Gamze , Danilina Marina
Published: July 2024

Since the 1950s, the remarkable amount of global environmental degradation has heightened environmental concerns at both national and international levels. This shift has spurred intensive research into the causes of environmental degradation and potential remedies, including environmental taxes, fines, education, and regulations. The drivers of CO2 emissions have been widely explored in the literature, but the nexus between business climate, human capital, and CO2 emissions has not been examined sufficiently. Therefore, the purpose of this study is to delve into the interplay between renewable energy, business climate, human capital, and CO2 emissions in BRICS countries from 2000 to 2020 using panel causality and cointegration tests. Our research hypotheses suggest that there are significant mutual interactions among renewable energy, business climate, human capital, and CO2 emissions based on the associated literature. The results of the causality test verify the research hypotheses by uncovering a bidirectional causality between business climate, renewable energy use, human capital, and CO2 emissions. Furthermore, the cointegration analysis reveals that increases in renewable energy use and human capital decrease CO2 emissions at the panel level, but a positive business climate increases CO2 emissions at the panel level. However, the impact of business climate on CO2 emissions at the country level varies among BRICS economies based on environmental policies. In conclusion, investing in green energy technologies and education is a useful tool to decrease CO2 emissions. In addition to this, the positive effect of business climate on CO2 emissions should be balanced by regulations to increase environmental, social, and governance awareness of firms.
Deep Learning Approaches for Power Prediction in Wind–Solar Tower Systems
Authors: Rushdi Mostafa A. , Yoshida Shigeo , Watanabe Koichi , Ohya Yuji , Ismaiel Amr
Published: July 2024

Wind–solar towers are a relatively new method of capturing renewable energy from solar and wind power. Solar radiation is collected and heated air is forced to move through the tower. The thermal updraft propels a wind turbine to generate electricity. Furthermore, the top of the tower’s vortex generators produces a pressure differential, which intensifies the updraft. Data were gathered from a wind–solar tower system prototype developed and established at Kyushu University in Japan. Aiming to predict the power output of the system, while knowing a set of features, the data were evaluated and utilized to build a regression model. Sensitivity analysis guided the feature selection process. Several machine learning models were utilized in this study, and the most appropriate model was chosen based on prediction quality and temporal criteria. We started with a simple linear regression model but it was inaccurate. By adding some non-linearity through using polynomial regression of the second order, the accuracy increased considerably sufficiently. Moreover, deep neural networks were trained and tested to enhance the power prediction performance. These networks performed very well, having the most powerful prediction capabilities, with a coefficient of determination R2=0.99734 after hyper-parameter tuning. A 1-D convolutional neural network achieved less accuracy with R2=0.99647, but is still considered a competitive model. A reduced model was introduced trading off some accuracy (R2=0.9916) for significantly reduced data collection requirements and effort.
Planning a Hybrid Battery Energy Storage System for Supplying Electric Vehicle Charging Station Microgrids
Authors: Khazali Amirhossein , Al-Wreikat Yazan , Fraser Ewan J. , Sharkh Suleiman M. , Cruden Andrew J. , Naderi Mobin , Smith Matthew J. , Palmer Diane , Gladwin Dan T. , Foster Martin P. , Ballantyne Erica E. F. , Stone David A. , Wills Richard G.
Published: July 2024

This paper presents a capacity planning framework for a microgrid based on renewable energy sources and supported by a hybrid battery energy storage system which is composed of three different battery types, including lithium-ion (Li-ion), lead acid (LA), and second-life Li-ion batteries for supplying electric vehicle (EV) charging stations. The objective of this framework is to determine the optimal size for the wind generation systems, PV generation systems, and hybrid battery energy storage systems (HBESS) with the least cost. The framework is formulated as a mixed integer linear programming (MILP) problem, which incorporates constraints for battery ageing and the amount of unmet load for each year. The system uncertainties are managed by conducting the studies for various scenarios, generated and reduced by generative adversarial networks (GAN) and the k-means clustering algorithm for wind speed, global horizontal irradiation, and EV charging load. The studies are conducted for three levels of unmet load, and the outputs are compared for these reliability levels. The results indicate that the cost of hybrid energy storage is lower than individual battery technologies (21% compared to Li-ion, 4.6% compared to LA, and 6% compared to second-life Li-ion batteries). Additionally, by using HBESS, the capacity fade of LA batteries is decreased (for the unmet load levels of 0, 1%, 5%, 4.2%, 6.1%, and 9.7%, respectively), and the replacement of the system is deferred proportional to the degradation reduction.
Harmonic Sequence Component Model-Based Small-Signal Stability Analysis in Synchronous Machines during Asymmetrical Faults
Authors: Zevallos Oscar C. , Gallego Landera Yandi A. , León Viltre Lesyani , Rohten Carrasco Jaime Addin
Published: July 2024

Power systems are complex and often subject to faults, requiring accurate mathematical models for a thorough analysis. Traditional time-domain models are employed to evaluate the dynamic response of power system elements during transmission system faults. However, only the positive sequence components are considered for unbalanced faults, so the small-signal stability analysis is no longer accurate when assuming balanced conditions for asymmetrical faults. The dynamic phasor approach extends traditional models by representing synchronous machines with harmonic sequence components, making it suitable for an unbalanced condition analysis and revealing dynamic couplings not evident in conventional methods. By modeling electrical and mechanical equations with harmonic sequence components, the study implements an eigenvalue sensitivity analysis and participation factor analysis to identify the variable with significant participation in the critical modes and consequently in the dynamic response of synchronous machines during asymmetric faults, thereby control strategies can be proposed to improve system stability. The article validates the dynamic phasor model through simulations of a single-phase short circuit, demonstrating its accuracy and effectiveness in representing the transient and dynamic behavior of synchronous machines, and correctly identifies the harmonic sequence component with significant participation in the critical modes identified by the eigenvalue sensitivity to the rotor angular velocity and rotor angle.
Virtualized Viscosity Sensor for Onboard Energy Management
Authors: Gascoin Nicolas , Valade Pascal
Published: July 2024

Essential for decision-making, measurement is a cornerstone of various fields including energy management. While direct methods exist for some quantities like length, most physico-chemical properties require indirect assessment based on observable effects. Historically, pressure was measured by the water column height, and temperature by mercury expansion. Recent advancements in artificial intelligence (AI) offer a transformative approach by combining vast datasets with traditional measurements. This holds immense potential for applications facing extreme conditions and involving complex fluids where measurement is extremely challenging (over 1500 K and 5 MPa). In this study, an AI model is evaluated to replace online rheometers (293–1173 K, 0.15–3.5 MPa). A machine learning model utilizes a neural network with up to 8000 neurons, eight hidden layers, and over 448 million parameters. Trained, tested, and validated on three experimental databases with over 600 test conditions, the New Generation Predicted Viscosity Sensor (NGPV sensor) achieves exceptional accuracy (less than 4.8 × 10−7 Pa·s). This virtualized sensor proves highly relevant for hypersonic airbreathing applications involving fuel degradation and energy conversion. It maintains excellent predictability (accuracy below 6 × 10−6 Pa·s) even at flow rates 10 times higher than calibration, surpassing traditional rheometers limited by calibration needs and a lower viscosity measurement threshold (10−4 Pa·s).
Unlocking the Potential: An In-Depth Analysis of Factors Shaping the Success of Smart and Bidirectional Charging in a Cross-Country Comparison
Authors: Zahler Jakob , Vollmuth Patrick , Ostermann Adrian
Published: July 2024

The increasing utilisation of the distribution grid caused by the ramp-up of electromobility and additional electrification can be eased with flexibility through smart and bidirectional charging use cases. Implementing market-oriented, grid-, and system-serving use cases must be tailored to the different national framework conditions, both in technical and regulatory terms. This paper sets out an evaluation methodology for assessing the implementation of smart and bidirectional charging use cases in different countries. Nine use cases are considered, and influencing factors are identified. The evaluation methodology and detailed analysis are applied to Austria, the Czech Republic, Denmark, Finland, France, Germany, Italy, the Netherlands, Spain, and Sweden. In every country, the implementation of vehicle-to-home use cases is possible. Realising market-oriented use cases is feasible in countries with a completed smart meter rollout and availability of tariffs with real-time pricing. Grid-serving and ancillary service use cases depend most on country-specific regulation, which is why no clear trend can be identified. Use cases that require direct remote controllability are the most distant from implementation. The overarching analysis provides orientation for the design of transnational products and research and can serve as a basis for a harmonisation process in regulation.
An Experimental and Numerical Investigation of a Heat Exchanger for Showers
Authors: Maciorowski Damian , Spychala Maciej Jan , Miedzinska Danuta
Published: July 2024

In the present study, using a combination of theoretical discussions, practical examples, and case studies, we sought to gain a comprehensive understanding of how numerical solutions could be used to improve the design and optimize the thermal efficiency of a heat exchanger that utilizes wastewater to reduce the domestic consumption of hot water. To this end, we developed a validated numerical model. We also carried out simulations and experiments, the results of which are presented in this paper. The novelty of this work derives from our use of a new heat exchanger design for a domestic shower, and from the presented experimental–numerical evidence that proves its efficiency. We found that use of our newly designed appliance improved thermal efficiency from 14% to 27%. Moreover, we estimated that the cost of manufacturing and installing such a device did not exceed that of a widely available drain grid. Using our newly designed exchanger, a family of four living in Poland could save EUR 38 (at 2022 values) and reduce CO2 emissions by 192 kg. An average European family could save EUR 68 and reduce CO2 emissions by 76 kg.
Research on Geological-Engineering Integration Numerical Simulation Based on EUR Maximization Objective
Authors: Chen Haoqi , Liu Hualin , Shen Cheng , Xie Weiyang , Liu Taixin , Zhang Junfu , Lu Jiangnuo , Li Zhenglan , Peng Yu
Published: July 2024

Shale gas reservoirs, as representative reservoirs in the Sichuan Basin, have attracted widespread attention regarding development. Using gas reservoir numerical simulation to assist development has greatly improved the work efficiency of workers. However, traditional gas reservoir numerical simulation is widely criticized for its inability to effectively integrate with geological and engineering factors. In this study, we proposed a geological engineering integration method that considers pre-fracturing parameters. We further applied it to a typical well (N03) in a certain block of the Sichuan Basin. The reliability of the method was determined through historical fitting. Based on the N03 geological model, the optimization range of fracturing construction parameters in adjacent areas was determined with the goal of maximizing EUR. Recommended values for widely distributed construction parameter combinations of Class II reservoirs were provided through orthogonal analysis. The influence order of fracturing construction parameters is (1) sand addition strength, (2) cluster spacing, (3) construction displacement, (4) fracture fluid strength, and (5) horizontal segment length. Finally, we compared the simulated data with the actual case. The results showed that an integrated numerical simulation method including geological and engineering factors can comprehensively and accurately assist in reservoir development.