bluuebunny/crossref_metadata_2025 huggingface dataset:
Up-Conversion Photoluminescence in Thulia and Ytterbia Co-Doped Yttria-Stabilized Zirconia Single Crystals
Authors: Huang Danni , Xiao Tong , Fu Beibei , Xu Shoulei , Huang Yuyang , Deng Wen , Zhou Zhukun
Published: March 2023

ZrO2 is an attractive host matrix for luminescence material because of its excellent physical properties, such as low phonon energy and wide band gap. In this work, the highly transparent Tm2O3 and Yb2O3 co-doped yttria stabilized zirconia (YSZ) (abbreviated as Yb/Tm: YSZ) single crystals were grown by the optical floating zone method. The Yb/Tm: YSZ samples were stabilized in the cubic phase at room temperature when Yb3+ and Tm3+ replaced Y3+. The influence of Yb3+ co-doping on the up-conversion luminescence properties of the crystals was systematically studied. A total of 0.5 mol% Tm2O3 and 2.0 mol% Yb2O3 co-activated YSZ single crystal (abbreviated as 2.0Yb/Tm: YSZ) has the maximum luminous intensity. There were seven absorption peaks located at around 358, 460, 679, 783.3, 850–1000, 1200, and 1721.5 nm that were observed in the absorption spectrum of the 2.0Yb/Tm: YSZ single crystal. There were three up-conversion peaks at around 488, 658 and 800 nm that were observed when the Yb/Tm: YSZ samples were excitated at 980 nm. The fluorescence lifetime of Tm3+ for the 1G4→3H6 transition of the 2.0Yb/Tm: YSZ sample is 7.716 ms as excited with a 980 nm laser. In addition, the oscillator strength parameters Ωλ (λ = 2, 4 and 6) of this sample were derived by the Judd–Ofelt theory to evaluate the laser performance of the host materials. The ratio Ω4/Ω6 of this sample is 0.80, implying its excellent laser output. Therefore, the 2.0Yb/Tm: YSZ single crystal is a considerable potential material for laser and luminescence applications.
Diversity and Community Structure of Typhlocybinae in the Typical Karst Rocky Ecosystem, Southwest China
Authors: Wang Jinqiu , Jiang Jia , Chi Yongkuan , Su Di , Song Yuehua
Published: March 2023

In karst ecosystems, different geographic environmental conditions can lead to different lithospheric conditions, thus determining community composition and altering biotic interactions. Guizhou Province is a typical ecologically fragile karst area located in the South China Karst. To explore the relationship between biodiversity and environmental changes in different karst habitats, the community structure of typhlocybinae (Hemiptera, Auchenorrhyncha, and Cicadellidae) in three typical karst areas in Guizhou Province (the Zhenfeng–Huajiang Demonstration Zone, the Bijie Salaxi Demonstration Zone, and the Shibing Yuntai Mountain Nature Reserve) was analyzed. These areas are characterized by differences in terms of their geographic environment. For field investigations, typhlocybinae specimens were collected from five common leafhopper host plants—Juglans regia L., Rhus chinensis Mill., Prunus persica (L.) Batsch, Prunus salicina Lindl., and Debregeasia orientalis C.J. Chen—in the three study areas. A total of 4078 typhlocybinae specimens were captured, belonging to 6 tribes, 40 genera, and 121 species. Among them, Alnetoidia dujuanensis, Limassolla lingchuanensis, and Singapora shinshana were the dominant species. The numbers of typhlocybinae specimens from each region were as follows: Shibing, 2170 (53.2%); Bijie, 973 (23.9%); and Huajiang, 935 (22.9%). The number of leafhoppers collected in areas with serious rocky desertification was low, and the number increased with the increase in vegetation coverage. The order of the influence of environmental factors on the community structure of the leafhoppers in the three study areas was Huajiang > Bijie > Shibing. This order is consistent with the ranking of rocky desertification grades in the three study areas. The order based on the number of units at different taxonomic levels was as follows: Bijie (6 tribes, 32 genera, and 68 species) > Huajiang (6 tribes, 22 genera, and 58 species) > Shibing (5 tribes, 21 genera, and 48 species). The results show that environmental factors, such as climate and host plant leaf traits, had various effects on the characteristics and diversity of the leafhopper communities in different grades of rocky desertification areas. This study demonstrates that there are differences in species diversity in different grades of karst rocky desertification areas and provides a theoretical basis for future rocky desertification control and regional ecological restoration.
Occurrence of Gastrointestinal Parasites in Synanthropic Neozoan Egyptian Geese (Alopochen aegyptiaca, Linnaeus 1766) in Germany
Authors: Fischer Ella F. , Recht Sabine , Vélez Juan , Rogge Linda , Taubert Anja , Hermosilla Carlos R.
Published: March 2023

Various studies have shown that the transmission and passage of alien and native pathogens play a critical role in the establishment process of an invasive species and its further spread. Egyptian geese (Alopochen aegyptiaca) are neozotic birds on various continents. They live not only in the countryside near fresh water bodies but also in urban habitats in Central Europe with close contact to humans and their pets. Although their rapid distribution in Europe is widely debated, scientific studies on the anthropozoonotic risks of the population and studies on the present endoparasites in Egyptian geese are rare worldwide. In the present study, 114 shot Egyptian geese and 148 non-invasively collected faecal samples of wild Egyptian geese from 11 different Federal States in Germany were examined. A total of 13 metazoan endoparasite species in 12 different genera were identified. The main endoparasites found were Hystrichis tricolor, Polymorphus minutus, and, in lesser abundance, Cloacotaenia sp. and Echinuria uncinata. Adult stages of Echinostoma revolutum, an anthropozoonotic heteroxenic trematode, were found in 7.9% of the animals examined postmortem. This species was additionally identified by molecular analysis. Although Egyptian geese live in communities with native waterfowl, it appears that they have a lower parasitic load in general. The acquisition of generalistic parasites in an alien species and the associated increased risk of infection for native species is known as “spill-back” and raises the question of impacts on native waterfowl. Differences between animals from rural populations and urban populations were observed. The present study represents the first large-scale survey on gastrointestinal parasites of free-ranging Egyptian geese.
IgG N-glycan Signatures as Potential Diagnostic and Prognostic Biomarkers
Authors: Haslund-Gourley Benjamin S. , Wigdahl Brian , Comunale Mary Ann
Published: March 2023

IgG N-glycans are an emerging source of disease-specific biomarkers. Over the last decade, the continued development of glycomic databases and the evolution of glyco-analytic methods have resulted in increased throughput, resolution, and sensitivity. IgG N-glycans promote adaptive immune responses through antibody-dependent cellular cytotoxicity (ADCC) and complement activation to combat infection or cancer and promote autoimmunity. In addition to the functional assays, researchers are examining the ability of protein-specific glycosylation to serve as biomarkers of disease. This literature review demonstrates that IgG N-glycans can discriminate between healthy controls, autoimmune disease, infectious disease, and cancer with high sensitivity. The literature also indicates that the IgG glycosylation patterns vary across disease state, thereby supporting their role as specific biomarkers. In addition, IgG N-glycans can be collected longitudinally from patients to track treatment responses or predict disease reoccurrence. This review focuses on IgG N-glycan profiles applied as diagnostics, cohort discriminators, and prognostics. Recent successes, remaining challenges, and upcoming approaches are critically discussed.
Identification of Genetic Alterations in Rapid Progressive Glioblastoma by Use of Whole Exome Sequencing
Authors: Khan Imran , Işık Esra Büşra , Mahfooz Sadaf , Khan Asif M. , Hatiboglu Mustafa Aziz
Published: March 2023

Background: Glioblastoma poses an inevitable threat to patients despite aggressive therapy regimes. It displays a great level of molecular heterogeneity and numerous substitutions in several genes have been documented. Next-generation sequencing techniques have identified various molecular signatures that have led to a better understanding of the molecular pathogenesis of glioblastoma. In this limited study, we sought to identify genetic variants in a small number of rare patients with aggressive glioblastoma. Methods: Five tumor tissue samples were isolated from four patients with rapidly growing glioblastoma. Genomic DNA was isolated and whole exome sequencing was used to study protein-coding regions. Generated FASTQ files were analyzed and variants were called for each sample. Variants were prioritized with different approaches and functional annotation was applied for the detrimental variants. Results: A total of 49,780 somatic variants were identified in the five glioblastoma samples studied, with the majority as missense substitutions. The top ten genes with the highest number of substitutions were MUC3A, MUC4, MUC6, OR4C5, PDE4DIP, AHNAK2, OR4C3, ZNF806, TTN, and RP1L1. Notably, variant prioritization after annotation indicated that the MTCH2 (Chr11: 47647265 A>G) gene sequence change was putative deleterious in all of the aggressive tumor samples. Conclusion: The MTCH2 (Chr11: 47647265 A>G) gene substitution was identified as putative deleterious in highly aggressive glioblastomas, which merits further investigation. Moreover, a high tumor mutation burden was observed, with a signature of the highest substitutions in MUC3A, MUC4, MUC6, OR4C5, PDE4DIP, AHNAK2, OR4C3, ZNF806, TTN, and RP1L1 genes. The findings provide critical, initial data for the further rational design of genetic screening and diagnostic approaches against aggressive glioblastoma.
Diagnostic Approaches to Vascular Injury in Polytrauma—A Literature Review
Authors: Ntola Vuyolwethu C. , Hardcastle Timothy C.
Published: March 2023

Background: Polytrauma is understood as significant injuries, occurring at the same time, to two or more anatomical regions (the ISS regions) or organ systems, with at least one of the injuries considered as posing a threat to life. Trauma is the main cause of unexpected demise in individuals below the age of 44 years and represents a huge burden on society. Vascular injury is highly morbid; it can lead to rapid exsanguination and death, posing a threat to both life and the limb. Independent predictors of outcome include mechanism of injury, associated injuries, and time from injury to definitive care. The mechanisms of vascular injury in the setting of polytrauma are either blunt, penetrating or a combination of the two. Methods: Comprehensive literature review of current diagnostic approaches to traumatic vascular injury in the context of polytrauma. The factors influencing the diagnostic approach are highlighted. The focus is the epidemiology of vascular injury and diagnostic approaches to it in the context of polytrauma. Results: Traumatic vascular injuries are associated with limb loss or even death. They are characterised by multiple injuries, the dilemma of the diagnostic approach, timing of intervention and higher risk of limb loss or death. The systematic approach in terms of clinical diagnosis and imaging is crucial in order save life and preserve the limb. The various diagnostic tools to individualise the investigation are discussed. Conclusion: This paper highlights the significance of timely and appropriate use of diagnostic tools for traumatic vascular trauma to save life and to preserve the limb. The associated injury also plays a crucial role in deciding the imaging modalities. At times, more than one investigation may be required.
The Importance of Immunohistochemistry in the Evaluation of Tumor Depth of Primary Cutaneous Melanoma
Authors: Pop Anca Maria , Monea Monica , Olah Peter , Moraru Raluca , Cotoi Ovidiu Simion
Published: March 2023

Primary cutaneous melanoma (PCM) is the most aggressive skin malignancy, with an increasing incidence and significant mortality. Tumoral invasion, expressed as Breslow thickness, is routinely assessed on hematoxylin and eosin (HE), although this stain may sometimes underestimate the tumoral depth. The aim of this study was to compare the efficiency of the immunohistochemical (IHC) markers S-100, SOX10, Melan-A, and HMB-45 with HE for the evaluation of the Breslow thickness and staging of PCM. This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022; for each case, the Breslow thickness using HE, S-100, SOX10, Melan-A, and HMB-45 was measured and the appropriate T category was recorded. The highest values of the Breslow thickness were observed for S-100. However, S-100, SOX10, and Melan-A provided statistically significant higher values of the Breslow thickness compared to HE, but no difference was noted between HMB-45 and HE. S-100 was most frequently involved in increasing the T category (26.1%), the majority of cases being upstaged from T1a to T1b. The IHC markers S-100, SOX10, and Melan-A contributed to better evaluation of the melanoma invasion, especially in thin melanomas, but their impact on staging and consecutive treatment remains to be confirmed by future studies.
Respiratory Variations of Central Venous Pressure as Indices of Pleural Pressure Swings: A Narrative Review
Authors: Umbrello Michele , Cereghini Sergio , Muttini Stefano
Published: March 2023

The measurement of pleural (or intrathoracic) pressure is a key element for a proper setting of mechanical ventilator assistance as both under- and over-assistance may cause detrimental effects on both the lungs and the diaphragm. Esophageal pressure (Pes) is the gold standard tool for such measurements; however, it is invasive and seldom used in daily practice, and easier, bedside-available tools that allow for rapid and continuous monitoring are greatly needed. The tidal swing of central venous pressure (CVP) has long been proposed as a surrogate for pleural pressure (Ppl); however, despite the wide availability of central venous catheters, this variable is very often overlooked in critically ill patients. In the present narrative review, the physiological basis for the use of CVP waveforms to estimate Ppl is presented; the findings of previous and recent papers that addressed this topic are systematically reviewed, and the studies are divided into those reporting positive findings (i.e., CVP was found to be a reliable estimate of Pes or Ppl) and those reporting negative findings. Both the strength and pitfalls of this approach are highlighted, and the current knowledge gaps and direction for future research are delineated.
Crossroads: Collaboration at the Intersection of Pandemic and Post-Pandemic Times
Authors: Tiernan Peter , Kenny Neil , McCarren Andrew
Published: March 2023

Discussions on the potential for technology to disrupt education have appeared at regular intervals for many years [...]
Improved Reconstruction Algorithm of Wireless Sensor Network Based on BFGS Quasi-Newton Method
Authors: Lu Xinmiao , Yang Cunfang , Wu Qiong , Wang Jiaxu , Wei Yuhan , Zhang Liyu , Li Dongyuan , Zhao Lanfei
Published: March 2023

Aiming at the problems of low reconstruction rate and poor reconstruction precision when reconstructing sparse signals in wireless sensor networks, a sparse signal reconstruction algorithm based on the Limit-Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) quasi-Newton method is proposed. The L-BFGS quasi-Newton method uses a two-loop recursion algorithm to find the descent direction dk directly by calculating the step difference between m adjacent iteration points, and a matrix Hk approximating the inverse of the Hessian matrix is constructed. It solves the disadvantages of BFGS requiring the calculation and storage of Hk, reduces the algorithm complexity, and improves the reconstruction rate. Finally, the experimental results show that the L-BFGS quasi-Newton method has good experimental results for solving the problem of sparse signal reconstruction in wireless sensor networks.
Research and Analysis on Contact Resistance of Wheel and Insulated Rail Joint in High-Speed Railway Stations
Authors: Li Junli , Zhang Youpeng , Zhao Bin , Zheng Zerong
Published: March 2023

Insulated rail joint (IRJ) as one of the components of the track circuit will be burned once the electric arc is generated when the train wheel passes through the insulated rail joint and the track circuit occurs the red-light band fault, which has a great impact on the safety of the train. Reducing the voltage at both ends of the insulated rail joint can effectively prevent the occurrence of electric arc. Clarifying the wheel-IRJ contact resistance is the basis for analyzing the voltage of wheel-IRJ. The effective apparent contact area of the wheel-IRJ contact was derived through the mathematical relation. Considering the surface roughness parameters, based on the electrical contact theory and the Greenwood-Williamson (GW) model, the mathematical models of the wheel-IRJ contact resistance and current density were established, and their influencing factors were analyzed. The results show that the contact resistance increased first and then decreased. The influences of load, roughness of the contact interface, and electric arc heat on the contact resistance were greater. Considering the influencing factors of contact resistance and current density, corresponding protective measures were proposed to reduce the potential difference at both ends of the insulated rail joint.
Studies on the Numerical Control Programming for Multi-Axis Machining of Turbomolecular Pump Rotor
Authors: Chen Teng-Hui , Lee Jeng-Nan , Shie Ming-Jhang , Chen Yu-Cheng
Published: March 2023

Turbomolecular pumps (TMPs), boasting advantageous high pumping rates, stability, and cleanliness, have been widely used in the semiconductor and photoelectric industries. In the aviation industry, the lightweight rotors of turbomolecular pumps can enhance the performance of generators. With technological advancements and increased industrial performance demands, various designs for turbomolecular pump rotors utilizing twisted and curved blade surfaces have been proposed. This increase in complexity runs parallel with machining difficulties. Contact and noncontact reverse engineering equipment was used to reconstruct a computer-aided design (CAD) model of turbomolecular pump rotors. The machining of thin and long blades, cutting tool arrangement, and toolpath was planned. Postprocessing was used to convert the toolpath into numerical control (NC) programming codes, which were combined with solid model cutting simulation software to verify the efficacy of the generated machining NC program for turbomolecular pump rotors. A five-axis horizontal machining center (CK type) with aluminum alloy AL6061-T6 was used to conduct actual machining tests measuring the efficiency of the machining methods. The rapid prototyping (RP) blocks can be creatively used as a jig and stuffed between the blades to suppress the chatter problem during processing, and the roughness of the surface of the blades can be reduced from 4.4 μm to 1.3 μm. The processed rotor can meet the flow test requirements, and the overall research can be used as a reference for the industry.
Mathematical Channel Modeling of Electromagnetic Waves in Biological Tissues for Wireless Body Communication
Authors: Krimi Intissar , Ben Mbarek Sofiane , Amara Selma , Choubani Fethi , Massoud Yehia
Published: March 2023

In the wireless body area network (WBAN), radio propagations from devices that communicate with the human body are very complex and distinctive compared to other environments. As we know, the human body is a lossy channel that significantly attenuates the propagation of electromagnetic waves (EMW). Therefore, channel models are critical in evaluating the communication link. One of the most predominant models is the path loss channel model, which is used to cover a wide range of communication channels and frequency bands in WBAN. This paper investigates the EMW in a human model irradiated by an incident electromagnetic plane wave. A planar multilayer structure is used for modeling human tissue. Moreover, the steady-state electromagnetic distribution is calculated by solving the differential and integral equations (DIE) by using the method of moments (MoM). The obtained results demonstrate the great use of performing a theoretical analysis for path loss (PL) and power loss density (PLD) estimation. The magnitude of the electric field inside muscle tissue at various depths, and with the most important frequencies in medical applications, is evaluated. This investigation provides evidence that the penetration of EMW in biological tissue strongly depends on the frequency and thickness of the tissue involved. Thus, for different examined conditions, an excellent agreement between recent results that were obtained by an analytical method, finite element (FEM), and the proposed MoM method is verified to be valid in this investigation, and it is found that the distribution of the field, PL, and PLD for different communication scenarios is very promising to determine the quality of communication for WBAN technology.
A Multi-Modal Story Generation Framework with AI-Driven Storyline Guidance
Authors: Kim Juntae , Heo Yoonseok , Yu Hogeon , Nang Jongho
Published: March 2023

An automatic story generation system continuously generates stories with a natural plot. The major challenge of automatic story generation is to maintain coherence between consecutive generated stories without the need for human intervention. To address this, we propose a novel multi-modal story generation framework that includes automated storyline decision-making capabilities. Our framework consists of three independent models: a transformer encoder-based storyline guidance model, which predicts a storyline using a multiple-choice question-answering problem; a transformer decoder-based story generation model that creates a story that describes the storyline determined by the guidance model; and a diffusion-based story visualization model that generates a representative image visually describing a scene to help readers better understand the story flow. Our proposed framework was extensively evaluated through both automatic and human evaluations, which demonstrate that our model outperforms the previous approach, suggesting the effectiveness of our storyline guidance model in making proper plans.
Research on Rolling Bearing Fault Diagnosis Based on Variational Modal Decomposition Parameter Optimization and an Improved Support Vector Machine
Authors: Li Lin , Meng Weilun , Liu Xiaodong , Fei Jiyou
Published: March 2023

Aiming at the problems of modal aliasing and poor noise resistance when processing the vibration acceleration signal of rolling bearings by empirical modal decomposition (EMD), a variational modal decomposition (VMD) method based on parameter optimization is proposed. Combined with the improved particle swarm optimization algorithm (IPSO) and improved envelope entropy, the VMD decomposition layers and penalty parameters were optimized. The components with high correlation coefficients with the original signal were screened out, and the fault characteristics were extracted by combining the sample entropy. Aiming at the low classification accuracy of the support vector machine with fixed parameters in the fault diagnosis stage and the defects of the gray wolf algorithm, such as insufficient population diversity and large influence of the initial population on the optimization effect, an improved gray wolf algorithm (IGWO) based on multistrategy improvement is proposed. The IGWO was combined with the support vector machine to obtain an improved gray wolf algorithm optimization support vector machine (IGWO-SVM). The rolling bearing fault diagnosis test bench is established to collect the vibration acceleration signals of rolling bearing under different states. The experimental results show that the fault diagnosis of rolling bearings with strong noise can be effectively realized by applying the above methods, and the average fault diagnosis accuracy rate reaches 98.875%.
Fault Location Method for an Active Distribution Network Based on a Hierarchical Optimization Model and Fault Confidence Factors
Authors: Zhao Qiao , Wang Zengping , Wang Yuxuan
Published: March 2023

With extensive access to distributed power sources and the rising electricity load, the structure and tide of distribution networks are becoming increasingly large and complex, leading to great challenges for fault location methods. In this paper, the power coupling phenomenon of the T-section in the distribution network is studied, and a hierarchical optimization model for fault location is proposed based on the port equivalence principle, which divides the fault location into two levels—area location and section location—to reduce the fault search dimension. Then, an improved binary particle swarm optimization algorithm (IBPSO) applied to the area location is proposed to improve the convergence accuracy and speed by optimizing the convergence criterion and integrating the chaotic mapping and mutation strategies. Finally, based on the topological characteristics of the sections in the fault area, a fault candidate scenario screening method based on the fault confidence factor is proposed to realize a second dimensionality reduction in the section location link. Simulation tests show that the proposed method demonstrates a good dimensionality reduction effect for large-scale, active distribution networks; additionally, the accuracy rate is improved by 25.7% and the location speed is improved by 300 ms when compared with traditional fault location methods.
Understanding the Influence of Biochar Augmentation in Anaerobic Digestion by Principal Component Analysis
Authors: Quintana-Najera Jessica , Blacker A. John , Fletcher Louise A. , Ross Andrew B.
Published: March 2023

Biochar addition in anaerobic digestion has been repeatedly reported to improve methane production, however, this ability is not well understood. This work aims to understand and correlate the most important factors influencing anaerobic digestion performance using principal component analysis along with quantitative and qualitative descriptive analysis to evaluate the variations of methane production with the addition of biochar. Reports from the literature using biochar produced from several feedstocks under variable pyrolysis conditions and therefore different compositions were carefully gathered and compared with their own non-biochar controls. Woody-derived biochars, produced at 450–550 °C, containing an ash content of 3.1–6.3%, and an O:C ratio of 0.20, were responsible for having the greatest positive effect. The amount of biochar added to the digesters also influences anaerobic digestion performance. Increasing biochar loads favours the production rate, although this can be detrimental to methane yields, thereby, biochar loads of approximately 0.4–0.6% (w/v) appear to be optimal. This work provides a guide for those interested in biochar augmentation in anaerobic digestion and identifies the main interactions between the variables involved.
Heterogeneous Catalytic Conversion of Terpenes into Biofuels: An Open Pathway to Sustainable Fuels
Authors: Lapuerta Magín , Tobío-Pérez Indira , Ortiz-Alvarez Marianela , Donoso David , Canoira Laureano , Piloto-Rodríguez Ramón
Published: March 2023

The production and use of terpene-based fuels represents a renewable source of energy in the transportation sector, especially in the aviation sector. The literature on the conversion of terpenes into valuable compounds is not new but has been based on the production of products for cosmetics and pharmaceutics. Several established chemical routes are also a way to develop drop-in fuels. The present work explores all the main chemical processes that can transform terpenes into more valuable fuels or additives, focusing on the use of heterogeneous catalysis, catalyst type, operating conditions, and reaction performance. α-pinene is the most studied catalyst, since it is the main component of turpentine. Isomerization is the most frequently applied chemical pathway used to enhance fuel properties, and a wide group of heterogeneous catalysts have been reported, with sulphonic acid resin catalysts, transition metals, alumina, and silicates being the most used. This work also explores the current production and commercialization of terpenes, as well as the challenges for their use as fuels at a commercial scale. The future challenge is to discover new catalysts or to improve the performance of the current products and reduce production costs. The feasibility of the production and commercialization of terpene-derived fuels is also linked to oil prices.
Microbial Fuel Cell Equipped with Bipolar Membrane Using Iron (III) Hydroxide as Final Electron Acceptor
Authors: Kazama Iori , Aso Yuji , Tanaka Tomonari , Ohara Hitomi
Published: March 2023

In this paper, we presented a novel microbial fuel cell (bMFC) structure, with a bipolar membrane separating the anode and cathode chambers. A bipolar membrane divides the bMFC into anode and cathode chambers. The bipolar membrane comprises anion and cation exchange layers. The anode chamber side has the cation exchange layer, while the cathode chamber side has the anion exchange layer. The anode chamber of the bMFC was loaded with Shewanella oneidensis MR-1 and lactic acid, while the cathode chamber was loaded with pure water and iron (III) hydroxide. The bMFC generated electrons for 20 days at a maximum current density of 30 mA/m2 and the ohmic resistance value was estimated to be 500 Ω. During the operation of the bMFC, both the anode and cathode chambers kept anaerobic conditions. There was no platinum catalyst in the cathode chamber, which is required for the reaction of protons with oxygen. Therefore, oxygen could not serve as an electron acceptor in the bMFC. We considered a bMFC mechanism in which protons produced by S. oneidensis react with hydroxide ions, the counter anions of Fe3+, inside the bipolar membrane to produce water. In other words, the electron acceptor in bMFC would be Fe3+.
Experimental Study on Denitration Transformation of CFB Boiler Burning Fujian Anthracite
Authors: Zhou Wenting , He Hongzhou , Zhuang Huanghuang
Published: March 2023

Two 75 t/h medium-temperature separated circulating fluidized bed boilers burning Fujian anthracite were upgraded with low NOx combustion (LNC). By reducing the effective cross-sectional area of the air distributor (from 13.43 m2 to 11.38 m2), improving the secondary air rate (from 40% to 45%), adjusting the secondary air supply method (adding a layer of upper secondary air, raising the height of the lower secondary air nozzle (0.4 m), and increasing the secondary air speed (from 48 m/s to 54 m/s), the reform of low nitrogen combustion was carried out. The transformation achieved remarkable results, i.e., the original NOx emission concentration can be controlled between 140–160 mg/m3 after the transformation, and the lowest value is below 120 mg/m3.
Microscopic Visualization Experimental Study on the Effect and Mechanism of Viscosity Reducer on Emulsification of Heavy Oil
Authors: Jiang Youwei , Wang Chao , Zhang Fusheng , Qi Zongyao , Liu Guoliang , Zhao Jiu , Zhou You , Wang Bojun , Lian Guofeng , Liu Pengcheng
Published: March 2023

Viscosity-reducer flooding is an effective method to improve oil recovery after the water flooding of heavy oil, and water-in-oil emulsion (W/O emulsion) is easily formed during this process. W/O emulsion has a strong ability to improve mobility ratio and block off high permeability layers, which can effectively improve sweep coefficient and enhance oil recovery. The microscopic visual glass model is mainly used to study the microscopic oil displacement mechanism of dilute oil; however, there are few studies on the emulsification mechanism and influencing factors of heavy oil. The purpose of this paper is to study the mechanism of heavy oil emulsification caused by viscosity reducer at the microscopic level, and the effect of emulsification on heavy oil recovery. The visible physical experiments with the glass microscopic models with different permeability and pore sizes were carried out to study the mechanism and main controlling factors of emulsification and the oil displacement effect of viscosity reducer. On this basis, the software was used to calculate the oil recovery in different areas of the model in different flooding stages, which provides a more intuitive understanding of the oil displacement effect of viscosity reducer. The results showed that there are mainly three types of emulsifications between pores: pore throat-breaking emulsification, blind-end emulsification, and pore channel extrusion emulsification. Hence, the mechanism of the three types of emulsifications and the relationship between droplet size with shear stress have been explored. The shear stress increased with the increase of the shear rate, and the oil droplet size in the model decreased with the increase of the shear. The blocking mechanism of pore throat and the shearing action of viscosity-reducer solution are the main mechanisms of viscous oil emulsification between pores. Generally, the particle size of the emulsified oil droplets formed by the blocking action is large, and it is easy to form pore throat emulsion. The particle size of emulsified oil droplets formed by shearing of viscosity-reducer solution is small. When the pore diameter is smaller than the particle size of oil droplets, the mobility of oil droplets between pores is poor, which means the oil droplets easily accumulate at the blind end to form residual oil. From the results of viscosity-reducer flooding experiments, the heavy oil recovery in each area of the model has been significantly improved after viscosity-reducer flooding compared with water flooding, with the recovery factor in the edge area of the model improving by up to 24.22%. The viscosity-reducer solution has a significant displacement effect on the residual oil in the edge area of the model.
Numerical Modeling and Simulation of a Spark-Ignition Engine Fueled with Ammonia-Hydrogen Blends
Authors: D’Antuono Gabriele , Lanni Davide , Galloni Enzo , Fontana Gustavo
Published: March 2023

Carbon-free fuels, in particular ammonia and hydrogen, could play a significant role in the decarbonization of the mobility sector. In this work, the authors assessed the operation of a light-duty spark-ignition engine fueled with an ammonia–hydrogen blend (85% ammonia and 15% hydrogen by volume) using a 1D predictive model. Three-dimensional computations have been used in order to verify the reliability of the 1D model. The addition of hydrogen to the air–fuel mixture allows the operating capacity of the engine to be extended with respect to neat ammonia fueling. The engine can be properly regulated between 1500 rpm and 3000 rpm. Its operating range reduces as engine speed increases, and it cannot run at 6000 rpm. This is due to different engine operating constraints being exceeded. The maximum engine torque is about 240 Nm and is reached at 1500 rpm. The engine efficiency ranges between 42% and 19%, and the specific fuel consumption varies from about 350 g/kWh to about 750 g/kWh. The results provide both performances and operating ranges of the engine allowing us to define optimized engine maps obtained by means of a constrained optimization.
Alternative Current Injection Newton and Fast Decoupled Power Flow
Authors: Coutinho de Oliveira Cristina , Bonini Neto Alfredo , Alves Dilson Amancio , Minussi Carlos Roberto , Castro Carlos Alberto
Published: March 2023

This article presents an alternative Newton-Raphson power flow method version. This method has been developed based on current injection equations formulated in polar coordinates. Likewise, the fast decoupled power flow, elaborated using current injection (BX version), is presented. These methods are tested considering electrical power systems composed of 57-, 118-, and 300-bus, as well as a realistic system of 787-bus. For the robustness analysis, simulations were performed considering different loading conditions and R/X ratios of the transmission line. Based on the simulations that were realized, there is evidence that the performance of the proposed current injection methods is similar to the power injection methods.
Improvement of Distance Protection with SVM on PV-Fed Transmission Lines in Infeed Conditions
Authors: Yoldas Yasar Beyazit , Yumurtacı Recep
Published: March 2023

Photovoltaic (PV) power plants have comparatively weak infeed characteristics, unlike conventional synchronous generators. The controllability of grid-connected inverters and the limited overcurrent capability of power electronic devices means that the characteristics of faults on transmission lines fed by PV power stations are substantially different than those on transmission lines fed by conventional sources. Operating performances of distance relays on PV-fed transmission line are unveiled. This paper analyses the impact of PV-fed transmission lines in infeed conditions on distance protection. Fault signals on the transmission line were generated by Digsilent PowerFactory software. Then, fault signals were analyzed by discrete Fourier transformation (DFT) with MATLAB software. The measured current and voltage signals were preprocessed first with DFT, and then machine learning via a support vector machine (SVM) was used for regression. This research proposes an improvement on distance protection with SVM for preventing maloperation in infeed conditions on PV fed transmission lines. The average accuracy was up to 95.6% in this study. The simulation was performed at different locations along the transmission line with different types of fault on a given power system model with the PV power plant.
Comparative Study of the Transmission Capacity of Grid-Forming Converters and Grid-Following Converters
Authors: Kong Bojun , Zhu Jian , Wang Shengbo , Xu Xingmin , Jin Xiaokuan , Yin Junjie , Wang Jianhua
Published: March 2023

The development trend of high shares of renewables and power electronics has increased the demand for new energy converters in the power system, but there is a lack of systematic research on the stability of different types of converters when transmitting power, which is worth exploring in depth. In this study, the power transfer capabilities of grid-forming and grid-following converters are investigated separately through an equivalent circuit diagram and phasor diagram when connected to the grid, and a quantitative relationship between converters’ power transmission limit and short circuit ratio under static stability conditions is obtained, leading to the conclusion that, in terms of power transmission, grid-forming converters are more suitable for weak grids with high damping and low inertia, whereas grid-following converters are more suitable for strong grids with high inertia. The conclusions are further verified by constructing the converter grid-connected models for different grid strengths through the PLECS simulation platform and the real-time simulation RTBOX1 and F28379D launchpad platform.
Comprehensive Thermodynamic Evaluation of the Natural Gas-Fired Allam Cycle at Full Load
Authors: Colleoni Lorenzo , Sindoni Alessio , Ravelli Silvia
Published: March 2023

In this study, thermodynamic modeling and simulations were used to optimize the design point performance of the Allam cycle. The topic fits perfectly with the strategies for power sector decarbonization toward net zero emission. In fact, it offers an environmentally friendlier alternative to natural gas combined cycle (NGCC) plants. The focus is on oxyfuel combustion that, combined with supercritical CO2 (sCO2) stream as working fluid, produces high-purity CO2, electricity, and water by means of a highly recuperated Brayton cycle. The former is ready for sequestration, pipeline injection, or other applications, such as enhanced oil recovery or industrial processes. Being designed within the last decade, large-scale plants are poorly documented in the published literature and not yet ready for operation. Accordingly, a thermodynamic model was developed for a net power (Pn) output of 300 MW. After validation against the little data available from academic studies, simulation sets were conceived to assess the impact of main process parameters on cycle efficiency. To that end, operating conditions of the compressor, turbine, and air separation unit (ASU) were varied in a parametric analysis, preparatory to performance optimization. For the chosen layout, the maximum net electric efficiency (ηel,n) was found to be 50.4%, without thermal recovery from ASU.
A New Bearing Fault Detection Strategy Based on Combined Modes Ensemble Empirical Mode Decomposition, KMAD, and an Enhanced Deconvolution Process
Authors: Damine Yasser , Bessous Noureddine , Pusca Remus , Megherbi Ahmed Chaouki , Romary Raphaël , Sbaa Salim
Published: March 2023

In bearing fault diagnosis, ensemble empirical mode decomposition (EEMD) is a reliable technique for treating rolling bearing vibration signals by dividing them into intrinsic mode functions (IMFs). Traditional methods used in EEMD consist of identifying IMFs containing the fault information and reconstructing them. However, an incorrect selection can result in the loss of useful IMFs or the addition of unnecessary ones. To overcome this drawback, this paper presents a novel method called combined modes ensemble empirical mode decomposition (CMEEMD) to directly obtain a combination of useful IMFs containing fault information. This is without needing to pass through the processes of IMF selection and reconstruction, as well as guaranteeing that no defect information is lost. Owing to the small signal-to-noise ratio, this makes it difficult to determine the fault information of a rolling bearing at the early stage. Therefore, improving noise reduction is an essential procedure for detecting defects. The paper introduces a robust process for extracting rolling bearings defect information based on CMEEMD and an enhanced deconvolution technique. Firstly, the proposed CMEEMD extracts all combined modes (CMs) from adjoining IMFs decomposed from the raw fault signal by EEMD. Then, a selection indicator known as kurtosis median absolute deviation (KMAD) is created in this research to identify the combination of the appropriate IMFs. Finally, the enhanced deconvolution process minimizes noise and improves defect identification in the identified CM. Analyzing real and simulated bearing signals demonstrates that the developed method shows excellent performance in extracting defect information. Compared results between selecting the sensitive IMF using kurtosis and selecting the sensitive CM using the proposed KMAD show that the identified CM contains rich fault information in many cases. Furthermore, our comparisons revealed that the enhanced deconvolution approach proposed here outperformed the minimum entropy deconvolution (MED) approach for improving fault pulses and the wavelet de-noising method for noise suppression.
Optimal Incorporation of Intermittent Renewable Energy Storage Units and Green Hydrogen Production in the Electrical Sector
Authors: Serrano-Arévalo Tania Itzel , Tovar-Facio Javier , Ponce-Ortega José María
Published: March 2023

This paper presents a mathematical programming approach for the strategic planning of hydrogen production from renewable energies and its use in electric power generation in conventional technologies. The proposed approach aims to determine the optimal selection of the different types of technologies, electrolyzers and storage units (energy and hydrogen). The approach considers the implementation of an optimization methodology to select a representative data set that characterizes the total annual demand. The economic objective aims to determine the minimum cost, which is composed of the capital costs in the acquisition of units, operating costs of such units, costs of production and transmission of energy, as well as the cost associated with the emissions generated, which is related to an environmental tax. A specific case study is presented in the Mexican peninsula and the results show that it is possible to produce hydrogen at a minimum sale price of 4200 $/tonH2, with a total cost of $5.1687 × 106 and 2.5243 × 105 tonCO2eq. In addition, the financial break-even point corresponds to a sale price of 6600 $/tonH2. The proposed model determines the trade-offs between the cost and the emissions generated.
A Tensile Rotary Airborne Wind Energy System—Modelling, Analysis and Improved Design
Authors: Tulloch Oliver , Yue Hong , Kazemi Amiri Abbas Mehrad , Read Roderick
Published: March 2023

A unique rotary kite turbine designed with tensile rotary power transmission (TRPT) is introduced in this work. Power extraction, power transmission and the ground station are modelled in a modular framework. The TRPT system is the key component of power transmission, for which three models with different levels of complexity are proposed. The first representation is based on the stationary state of the system, in which the external and internal torques of a TRPT section are in equilibrium, referred to as the steady-state TRPT model. The second representation is a simplified spring-disc model for dynamic TRPT, and the third one is a multi-spring model with higher degrees of freedom and more flexibility in describing TRPT dynamics. To assess the torque loss on TRPT, a simple tether drag model is written for the steady-state TRPT, followed by an improved tether drag model for the dynamic TRPT. This modular framework allows for multiple versions of the rotor, tether aerodynamics and TRPT representations. The developed models are validated by laboratory and field-testing experimental data, simulated over a range of modelling options. Model-based analysis are performed on TRPT design, rotor design and tether drag to understand any limitations and crucial design drivers. Improved designs are explored through multi-parameter optimisation based on steady-state analysis.
Properties and Uses of Biochars Incorporated into Mortars
Authors: Mota-Panizio Roberta , Carmo-Calado Luís , Assis Ana , Matos Vitor , Hermoso-Orzáez Manuel , Romano Pedro , Gonçalves Margarida , Brito Paulo
Published: March 2023

The construction industry is responsible for a large amount of CO2 emissions and an intensive energy consumption. Cement production is the third largest source of anthropogenic CO2 emissions and is responsible for about 1.8 Gt of CO2 emissions into the atmosphere. The use of waste materials to replace a fraction of cement in the mortar makes it more economically and ecologically friendly. In this work, the main objective was to test incorporations of biochar produced at temperatures of 300, 350, and 400 °C, as a partial replacement for cement in the production of mortar. The materials used for the tests were residual lignocellulosic biomass (WBL) and electrical cable insulation waste (WIEC) mixed in a ratio of 1:1. The biochars produced were crushed and sieved after production to reduce the particles. A sample of biochar was used and tested under these conditions and another sample was washed in water and dried before being incorporated; all tests were carried out with a 5% replacement. Waste recovery tests were also carried out without thermochemical treatment. The specimens were studied for compressive strength and water absorption by immersion. All tests were replicated and were analyzed and compared with a control mixture with no incorporation of biochar in the mixture. It was possible to observe that the tests with the incorporation of biochars at 400 °C showed better results, with only a 24% reduction in resistance to compression.