bluuebunny/crossref_metadata_2025 huggingface dataset:
Compromised Cranio-Spinal Suspension in Chiari Malformation Type 1: A Potential Role as Secondary Pathophysiology
Authors: Shao Belinda , Poggi Jonathan A. , Amaral-Nieves Natalie , Wojcik Daniel , Ma Kevin L. , Leary Owen P. , Klinge Petra M.
Published: December 2022

In Chiari Malformation Type I (CM1), low-lying tonsils obstruct the cisterna magna at the foramen magnum, thereby compromising the essential juncture between the cranial and spinal compartments. The anatomical obstruction of the cisterna magna inhibits bi-directional CSF flow as well as CSF pulse pressure equilibration between the intracranial compartment and the intraspinal compartment in response to instances of increased intracranial pressure. Less understood, however, are the roles of the spinal cord suspension structures at the craniocervical junction which lend viscoelastic support to the spinal cord and tonsils, as well as maintain the anatomical integrity of the cisterna magna and the dura. These include extradural ligaments including the myodural bridges (MDBs), as well as intradural dentate ligaments and the arachnoid framework. We propose that when these elements are disrupted by the cisterna magna obstruction, tonsillar pathology, and altered CSF dynamics, there may arise a secondary pathophysiology of compromised and dysfunctional cranio-spinal suspension in CM1. We present intraoperative images and videos captured during surgical exposure of the craniocervical junction in CM1 to illustrate this proposal.
Investigation of the Viability of Unmanned Autonomous Container Ships under Different Carbon Pricing Scenarios
Authors: Jovanović Ivana , Perčić Maja , Koričan Marija , Vladimir Nikola , Fan Ailong
Published: December 2022

Autonomous and unmanned shipping are currently trending research topics within the maritime sector, with the promise of a reduction in operating costs and an increase in safety. Although they bring higher investment costs, due to the long lifetime of ships, autonomous ships are expected to bring savings during ship exploitation. This paper aims to analyze capital and operating costs of five different sizes and route length container ships (conventional ships), and under a set of assumptions analyze the same costs for equivalent autonomous ships. A ship cost model is formed, where the typical cost scheme (investment and exploitation costs) is extended by the potential carbon pricing. Carbon pricing is taken into account due to the fact that the design procedure for autonomous and unmanned ships requires the employment of a next-generation regulatory framework. All results indicate the significant economic benefit of autonomous ships over conventional ones. Sensitivity analysis reveals that fuel and emission costs have a great influence on the overall profitability of autonomous vehicles. Although the literature review indicates that reduced operating costs due to crew removal will bring savings for autonomous shipping, results show that savings due reduced operating costs is minor.
Spatial and Statistical Analysis of Operational Conditions Contributing to Marine Accidents in the Singapore Strait
Authors: Yildiz Serdar , Tonoğlu Fatih , Uğurlu Özkan , Loughney Sean , Wang Jin
Published: December 2022

Narrow waterways are important connection hubs, also known as logistics transfer nodes, within maritime transport, where maritime traffic can become very dense and congested. Heavy traffic, unsuitable environmental conditions and human errors make narrow waterways risky areas for marine accident occurrence. Accidents in narrow waterways cause ship damage, loss of cargo, loss of life and environmental disasters, as well as interruption of maritime transport and negative impact on the economy. Thus, the sustainability of navigational safety in narrow waterways has been the focus of attention of all beneficiaries in the maritime industry. The Singapore Strait is one of the busiest narrow waterways in the world in terms of the number of ships transiting. Sustaining and safe maritime transport in the Singapore Strait is significantly important for the sustainability of the global trade. Therefore, it is vitally important to appropriately identify the threats to safety of navigation in the Singapore Strait. In this study, the operational conditions that have played a role in the occurrence of accidents in the Singapore Strait are examined. For this purpose, using the Geographical Information System (GIS), the areas where marine accidents are concentrated were determined by the Kernel Density Analysis method and a “Marine Accidents Density Map” was created for the Singapore Strait. The relationship between the dense areas in the marine accidents density map and the operational conditions that play a role in the accidents in the Singapore Strait were examined using the Chi-Square Test and expert opinions. The results of the study indicate that if there is a condition (e.g., turning, joining to the traffic stream, or failure in propulsion/steering systems) that directly or indirectly disturbs the normal flow of traffic in the Singapore Strait, the risk of having an accident increases. The results of this study can be used to determine the measures to be taken for the prevention of possible accidents, as well as to help manage the risks associated with the ships that pass through the region.
Risk Stratification of Local Flaps and Skin Grafting in Skin Cancer-Related Facial Reconstruction: A Retrospective Single-Center Study of 607 Patients
Authors: Mamsen Frederik Penzien Wainer , Kiilerich Claes Hannibal , Hesselfeldt-Nielsen Jørgen , Saltvig Iselin , Remvig Celine Lund-Nielsen , Trøstrup Hannah , Schmidt Volker-Jürgen
Published: December 2022

Background: Non-melanoma skin cancer (NMSC) takes up a substantial fraction of dermatological and plastic surgical outpatient visits and surgeries. NMSC develops as an accumulated exposure to UV light with the face most frequently diagnosed. Method: This retrospective study investigated the risk of complications in relation to full-thickness skin grafts (FTSG) or local flaps in 607 patients who underwent facial surgery and reconstruction at a high-volume center for facial cancer surgery at a tertiary university hospital. Results: Between 01.12.2017 and 30.11.2020, 304 patients received reconstructive flap surgery and 303 received FTSG following skin cancer removal in the face. Flap reconstruction was predominantly performed in the nasal region (78%, n = 237), whereas FTSG reconstruction was performed in the nasal (41,6%, n = 126), frontal (19.8%, n = 60), and temporal areas (19.8%, n = 60), respectively. Patients undergoing FTSGs had a significantly higher risk of hematoma (p = 0.003), partial necroses (p < 0.001), and total necroses (p < 0.001) compared to flap reconstruction. Age and sex increased the risk of major complications (hematoma, partial or total necrosis, wound dehiscence, or infection) for FTSG, revealing that men exhibited 3.72 times increased risk of major complications compared to women reconstructed with FTSG. A tumor size above 15 mm increased the risk of hematoma and necrosis significantly. In summary, local flaps for facial reconstruction after skin cancer provide lower complication rate compared with FTSGs, especially in elderly and/or male patients. The indication for FTSG should be considered critically if the patient’s tumor size and location allow for both procedures.
Geoheritage of the Precious Opal Bearing Zone in Libanka Mining District (Slovakia) and Its Geotourism and Geoeducation Potential
Authors: Palgutová Silvia , Štrba Ľubomír
Published: December 2022

The northern part of the Slanské Vrchy Mountains, in Slovakia, within the territory of Dubnik Opal Mines, is considered to be the historical source of opal, including the opal known to the Romans. Dubnik precious opal mineralization originating from post-magmatic hydrothermal fluids based on its values should be recognized as an area of global importance. Geological processes that are connected to Neogene volcanic activity took place in the territory of the Dubnik Opal Mines and resulted in the formation of various geological products and processes represented by polymetallic mineral formation, opal formation, antimonite formation, and mineralization of the supergene stage, as well as the stratovolcano rock environment, which are of geoheritage significance. Remnants of intensive mining activity that took place during the past 2000 years provide opportunities for visitors to explore, study, and appreciate this unique geological heritage of international importance. However, geo-interpretation aimed at the general public (the largest group of potential visitors from sustainable geotourism development) and research on (geo)tourism and/or geoheritage for tourism purposes, as discussed in this paper, are lacking.
Soil Erosion across Scales: Assessing Its Sources of Variation in Sahelian Landscapes under Semi-Arid Climate
Authors: Mounirou Lawani Adjadi , Yonaba Roland , Tazen Fowé , Ayele Gebiaw T. , Yaseen Zaher Mundher , Karambiri Harouna , Yacouba Hamma
Published: December 2022

Soil erosion varies in space and time. As the contributing surface area increases, heterogeneity effects are amplified, inducing scale effects. In the present study, soil erosion processes as affected by the observation scale and the soil surface conditions are assessed. An experimental field scale setup of 18 plots (1–150 m2) with different soil surface conditions (bare and degraded, cultivated) and slopes (0.75–4.2%) are used to monitor soil losses between 2010 to 2018 under natural rainfall. The results showed that soil loss rates range between 2.5 and 19.5 t.ha−1 under cultivated plots and increase to 12–45 t.ha−1 on bare and degraded soils, which outlines the control of soil surface conditions on soil erosion. At a larger scale (38 km2), soil losses are estimated at 2.2–4.5 t.ha−1, highlighting the major contribution of scale. The scale effect is likely caused by the redistribution of sediments in the drainage network. These findings outline the nature and contribution of the emerging and dominant soil erosion processes at larger scales. At the plot scale, however, diffuse erosion remains dominant, since surface runoff is laminar and sediment transport capacity is limited, resulting in lower soil erosion rates.
Study on Friction Characteristics of Slipper Pair of Large Displacement High-Pressure Piston Pump
Authors: Li Zekui , Xu Shunhai , Gong Guofang , Bi Yankun , Xu Liping , Zhang Liang , Ren Zhen
Published: December 2022

The reference value of the oil film thickness and friction coefficient of the slipper pair is critical to the development of the piston pump, especially for 750 mL/r displacement piston pumps. To explore the computing method and range of the reference value mentioned applicable to 750 mL/r displacement piston pumps, this study aims to propose the modified calculation model of the oil film thickness based on the real clearance flowrate and obtain the value range of the friction coefficient of the slipper pair. Through the friction test of the slipper pair, the mean deviation ratio of the oil film thickness between the modified value, theoretical value, and the measured value was calculated and compared, respectively. The variation law of the friction under the influence of different speeds and working pressures was analyzed. Finally, the range of the equivalent friction coefficient with the upper and lower limit surfaces was obtained. The results show that the mean deviation ratio between the modified oil film thickness value and the measured value is mainly within 6%, while that of the theoretical method is mainly from 6% to 8%, and the mean of the difference between the two deviation ratios is about 3%, verifying the feasibility of the modified model used for the calculation of the reference value. Meanwhile, the value of the equivalent friction coefficient fluctuates in the range of 0.006–0.018, which is affected more significantly by the working pressure than the speed, suggesting that the working pressure can be given priority as the design basis of the friction coefficient for 750 mL/r displacement piston pumps.
Creep Behavior of A356 Aluminum Alloy Reinforced with Multi-Walled Carbon Nanotubes by Stir Casting
Authors: Shan L. , Tan C. Y. , Shen X. , Ramesh S. , Kolahchi R. , Hajmohammad M. H. , Rajak D. K.
Published: December 2022

Lightweight aluminum alloy components are often used to manufacture a variety of engineering components in many industries. In recent years, researchers have studied the effect of improving the mechanical properties of metal alloys by incorporating nano-carbon into its structure. In this study, the effect of the addition of 0.2, 0.5, and 1 wt% of multi-walled carbon nanotubes (MWCNTs) on the stress–strain behavior and creep phenomenon of an A356 aluminum alloy were studied. The effect of nickel coating on 0.2 wt% MWCNTs was also investigated. Samples were prepared using the stir-casting method. The results revealed that the grain size became finer when MWCNT nano-particulates were introduced. Although the MWCNTs were distributed homogeneously in the A356 matrix, as confirmed by FESEM analysis, there were some agglomerations observed in a specific area with dimensions smaller than 100 nm. Nevertheless, the addition of MWCNTs was found to be beneficial in enhancing the hardness of alloys containing 0.2 wt%, 0.2 wt% nickel-coated, 0.5 wt%, and 1 wt% MWCNTs by 9%, 24%, 32%, and 15%, respectively, as compared with the unreinforced A345 matrix. It was also found that the 0.5 wt% MWCNT-A356 matrix exhibited an improvement in the creep lifetime by more than two orders of magnitude.
The Influence of Potassium Salts Phase Stabilizers and Binder Matrix on the Properties of Novel Composite Rocket Propellants Based on Ammonium Nitrate
Authors: Rotariu Traian , Pulpea Bogdan-Gheorghe , Dîrloman Florin-Marian , Diacon Aurel , Rusen Edina , Toader Gabriela , Zvîncu Neculai-Daniel , Iordache Tanţa-Verona , Botiș Răzvan Horia
Published: December 2022

The environmental impact and availability of ingredients are vital for the new generation of rocket propellants. In this context, several novel composite propellants were prepared based on the “greener” oxidizer phase-stabilized ammonium nitrate (PSAN), a micronized aluminum–magnesium alloy fuel, iron oxide powder burn rate modifier, triethylene glycol dinitrate (TEGDN) energetic plasticizer and a polyurethane (PU) binder. The novelty of this study is brought by the innovative procedure of synthesizing and combining the constituents of these heterogeneous compositions to obtain high-performance “eco-friendly” rocket propellants. The polymorphism shortcomings brought by ammonium nitrate in these energetic formulations have been solved by its co-crystallization with potassium salts (potassium nitrate, potassium chromate, potassium dichromate, potassium sulphate, potassium chlorate and potassium perchlorate). Polyester–polyol blends, resulting from recycled post-consumer polyethylene terephthalate (PET) glycolysis, were utilized for the synthesis of the polyurethane binder, especially designed for this type of application. To adjust the energetic output and tailor the mechanical properties of the propellant, the energetic plasticizer TEGDN was also involved. The performance and safety characteristics of the novel composites were evaluated through various analytical techniques (TGA, DTA, XRD) and specific tests (rate of combustion, heat of combustion, specific volume, chemical stability, sensitivity to thermal, impact and friction stimuli), according to NATO standards, providing promising preliminary results for further ballistics investigations.
Dynamics Analysis and Deep Learning-Based Fault Diagnosis of Defective Rolling Element Bearing on the Multi-Joint Robot
Authors: Zhang Wentao , Zhang Ting , Cui Guohua , Pan Ying
Published: December 2022

Industrial robots typically perform a variety of tasks and occupy critical positions in modern manufacturing fields. When certain failures occur in the internal structures of robots, it tends to result in significant financial loss and the consumption of human resources. As a result, timely and effective fault diagnosis is critical to ensuring the safe operation of robots. Deep learning-based methods are currently being widely used by researchers to address some shortcomings of traditional methods. However, due to realistic factor limitations, few researchers take the failure pattern of rotating machinery and the location of fault joints into account at the same time, so the fault types of multi-joint robots are not thoroughly investigated. In this case, we proposed a dynamic simulation method that considers the effects of bearing failures at various faulty joint locations and makes it possible to investigate more possible failure cases of multi-joint robots. In addition, we used LSTM and DCNN to perform staged fault diagnosis tasks, allowing us to gradually locate faulty joints and investigate detailed failure forms. According to the experimental results, distinguishable vibration signals corresponding to various fault states are successfully obtained, and our implemented algorithms are validated for their advanced performance in diagnosis tasks via comparative experiments.
Optimal Stator and Rotor Slots Design of Induction Motors for Electric Vehicles Using Opposition-Based Jellyfish Search Optimization
Authors: Juhaniya Ahamed Ibrahim Sithy , Ibrahim Ahmad Asrul , Mohd Zainuri Muhammad Ammirrul Atiqi , Zulkifley Mohd Asyraf , Remli Muhammad Akmal
Published: December 2022

This study presents a hybrid optimization technique to optimize stator and rotor slots of induction motor (IM) design for electric vehicle (EV) applications. The existing meta-heuristic optimization techniques for the IM design, such as genetic algorithm (GA) and particle swarm optimization (PSO), suffer premature convergence, exploration and exploitation imbalance, and computational burden. Therefore, this study proposes a new hybrid optimization technique called opposition-based jellyfish search optimization (OBJSO). This technique adopts opposition-based learning (OBL) into a jellyfish search optimization (JSO). Apart from that, a multi-objective formulation is derived to maximize the main performance indicators of EVs, including efficiency, breakdown torque, and power factor. The proposed OBJSO is used to solve the optimal design of stator and rotor slots based on the formulated multi-objective. The performance is compared with conventional optimization techniques, such as GA, PSO, and JSO. OBJSO outperforms three other optimization techniques in terms of average fitness by 2.2% (GA), 1.3% (PSO), and 0.17% (JSO). Furthermore, the convergence rate of OBJSO is improved tremendously, where up to 13.6% reduction in average can be achieved compared with JSO. In conclusion, the proposed technique can be used to help engineers in the automotive industry design a high-performance IM for EVs as an alternative to the existing motor.
Metaheuristics in Business Model Development for Local Tourism Sustainability Enhancement
Authors: Thumrongvut Pawnrat , Sethanan Kanchana , Jamrus Thitipong , Wongloucha Chuleeporn , Pitakaso Rapeepan , Golinska-Dawson Paulina
Published: December 2022

This study focused on analyzing planning and scheduling services in the tourism industry. Because dealing with these issues necessitates consideration of several important factors and stakeholders in the tourism business, it is challenging to operate resources efficiently. The purpose of this research is to propose a novel approach that allows maximizing the profits of tourism-related service sectors while considering many real-life constraints, such as sequence-dependent travel time, tourist time windows, points of interest, and specific destination constraints. We test our mathematical model for solving first small-scale problems and then metaheuristics proposed for finding a solution for real-life size problems. Moreover, sensitivity analysis was used to analyze the case study’s worthiness when the total cost and the revenue factor were changed. A real case study from Thailand’s Khon Kaen and Kanchanaburi provinces were used to verify the proposed models. The results indicate that the proposed models can be applied to investment decisions and strategy development. Furthermore, the outputs of the proposed models (i.e., the mathematical and metaheuristics models) can be employed to enhance the sustainability of other supply chains.
Applying the Push-Pull Mooring to Explore Consumers’ Shift from Physical to Online Purchases of Face Masks
Authors: Yu Sung-Wen , Liu Jun-Yan , Lin Chien-Liang , Su Yu-Sheng
Published: December 2022

In response to the emergency management caused by COVID-19, Taiwan began to impose a name-based rationing system for the purchase of face masks by having consumers visit physical stores and preorder them online. By doing so, the risk of face mask shortages caused by panic buying was reduced. To understand consumers’ willingness to switch from buying face masks at physical stores to preordering them online, we used a push-pull-mooring (PPM) model to measure related dimensions. We administered an online questionnaire survey and collected 233 valid responses. In the present study, perceived risk (including time risk, psychological risk and social risk) was treated as a second-order formative indicator, while pull effect was measured by the variables of critical mass and alternative attraction. Mooring effect was measured by switching cost. Through structural equation modeling (SEM), perceived risk, as well as critical mass and alternative attraction, had a significant effect on switching intention, while switching cost had no significant relationship with switching intention. This study investigated whether perceived risk (time risk, psychological risk and social risk), critical mass, alternative attraction and switching cost can serve as references for purchase behaviors amid future emergency management, through the prism of population migration theory, and proposed recommendations for their promotion and implementation.
A New Set of 3D Shifted Fractional-Order Gegenbauer Descriptors for Volumetric Image Representation
Authors: Khafaga Doaa Sami , Alhussan Amel Ali , Darwish Mohamed M. , Hosny Khalid M.
Published: December 2022

Volumetric images have a three-dimensional (3D) view, in which viewers can examine their characteristics from any angle. The more accurate the digital representation of volumetric images, the more precise and valuable the assessment of what these images represent. The representation of volumetric images is a significant area of study in pattern recognition and computer vision. Recently, volumetric image analysis using orthogonal moments with fractional order has opened up a new study pathway, which has led scholars to discover many real-life applications through investigating efficient algorithms to represent the features of 3D images. In this study, a new set of 3D shifted fractional-order Gegenbauer moments (FrGMs) for volumetric image representation is proposed. First, a mathematical description of the shifted Gegenbauer moments for 3D images is presented. Second, a fast, highly accurate method for calculating the fractional-order shifted Gegenbauer moments of 3D images is introduced. Finally, the efficiency of the proposed FrGMs is evaluated through various suitable experiments and compared with existing methods in terms of the reconstruction of 3D images, the invariability property, sensitivity to noise, and computation time. The experimental results clearly show that FrGMs outperform existing related algorithms.
Minimally Invasive Resection of Benign Osseous Tumors of the Spinal Column: 10 Years’ Experience and Long-Term Outcomes of a Specialized Center
Authors: Salame Khalil , Lidar Zvi , Khashan Morsi , Ofir Dror , Regev Gilad J.
Published: December 2022

Background and Objectives: Benign osseous tumors of the spinal column comprise about 10% of all spinal tumors and are rare cause for surgery. However, these tumors pose various management challenges and conventional surgery may be associated with significant morbidity. Previous reports on minimally invasive resection of these lesions are rare. We report a series of patients managed by total resection of benign osseous spine tumors using MIS techniques. Surgical decisions and technical considerations are discussed. Materials and Methods: A retrospective evaluation of prospectively collected data of patients who underwent minimally invasive surgery for removal of benign osseous vertebral tumors. Demographic, clinical and radiographic features, operative details and final pathological reports were summarized. Primary outcomes were completeness of tumor resection and pain relief assessed by VAS for back and leg pain. Secondary outcome measures were recurrence of tumor on repeat post-operative MRI and postoperative unstable deformity on standing scoliosis X-rays. Results: This series included 32 cases of primary osseous spine tumors resected by minimally invasive techniques. There were 17 males and 15 females aged 5–68 years (mean 23.3). The follow-up period was 8–90 months (mean 32 months) and the preoperative symptoms duration was 9–96 months. Axial spinal pain was the presenting symptom in all the patients. Five patients also complained about radicular pain and four patients had antalgic scoliosis. The tumor involved the thoracic spine in 12 cases, the lumbar segment in 11, the cervical in 5 and the sacral area in 4 cases. Complete tumor removal was performed in all patients. No procedure-related complications were encountered. Histopathology showed osteoid osteoma in 24 patients, osteoblastoma in 5 patients, and fibrous dysplasia, fibroadenoma and eosinophilic granuloma in one case each. All patients experienced significant pain relief after surgery, and had stopped pain medications by 12 months postoperatively. No patient suffered from tumor recurrence or spinal deformity. Conclusions: Minimally invasive surgery is feasible for total removal of selected benign vertebral tumors and may have some advantages over conventional surgical techniques.
Fe3O4 Coated SiO2 Magnetic Nanoparticles for Enhanced Antibacterial Activity and Electrochemical Sensing
Authors: Madhavi  , Kumar Mukesh , Ansari Jamilur R. , Kumar Vinay , Nagar Sushil , Sharma Ashutosh
Published: December 2022

Multifunctional magnetic composite nanoparticles (NPs) with antibiotics have demonstrated symbiotic effects because of their promising antimicrobial properties. The antimicrobial agent reduces side effects and dosage, and increases drug delivery efficiency. In this study, SiO2 coated over Fe3O4 magnetic nanoparticles (MNPs) were prepared by a solvothermal method. The MNPs were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR). The antimicrobial tests were carried out using the disk diffusion method. The electrochemical sensing was investigated by cyclic voltammetry with varying As(III) concentrations from 1–10 ppb. The microstructural results showed the formation of spherical-shaped Fe3O4@SiO2 MNPs with 15–30 nm diameters. UV-vis results showed that Fe3O4 NPs promote visible light absorption of Fe3O4@SiO2 MNPs because of well-structured and unvarying shell thickness which is beneficial for the absorption of organic dyes. With an increase in the concentration of As(III), there was a shift in potential and an increase in oxidation peak current, showing the electrocatalytic capacity of the modified electrode. The SiO2 deposited on Fe3O4 displayed an admirable microbial operation. These Fe3O4@SiO2 MNPs are easily absorbed by cells and have the potential to influence bacterial cells both within and outside of the cell membrane, making them an intriguing candidate for use in a variety of biological applications in the future.
Effect of Normalising Process on the Corrosion Behaviour of U75V Rail Flash Butt Welded Joints in a Marine Environment
Authors: Zhang Xi , Liao Tingting , Lv Qibing , Gou Guoqing
Published: December 2022

U75V rail steel is widely used in railways in China, including train tunnels in mountain and subsea projects, where it suffers from selective corrosion near welded joints. To ensure adequate railway service life, this study examines the effect of the normalisation process on the electrochemical behaviour of U75V rail-welded joints (URWJs) manufactured by flash butt welding (FBW) using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS). Corrosion morphology and elemental distribution analyses were performed to investigate the corrosion behaviour. The results show that the grains within the joints became finer and more homogeneous after normalisation, with a lower corrosion rate and higher corrosion resistance. It is demonstrated that fewer corrosion products were formed on the surface of the normalised joints after electrochemical test, and the corrosion resistance of the URWJs improved, owing to the formation of denser passivation films caused by normalisation. These mechanisms of corrosion response help explain corrosion failure in railway lines, as well as also help optimise the welding process and normalising processes to obtain a corrosion-resistant microstructure and ensure the quality of welded joints.
Influence of Partitioning Temperature on Microstructure and Mechanical Performance of Medium Manganese Fe-C-Mn-Cu-Cr-Mo-Nb Steel
Authors: Lin Tao , Feng Yan , Liu Lei , Jing Cainian , Wu Zhonglin , Li Zhaotong , Zhao Jingrui
Published: December 2022

A hot-rolled medium manganese Q&P steel was annealed at an intercritical annealing temperature (670 °C) and quenched to four partitioning temperatures (300 °C, 280 °C, 260 °C, and 240 °C). The effect of the partitioning temperature on the microstructure and mechanical properties of the steel was studied. The microstructure evolution at different partitioning temperatures was characterized using scanning electron microscopy (SEM), a transmission electron microscope (TEM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). The results showed that, as the partition temperature increased, the fractions and the size of the fresh massive martensite (M2) increased, the initial lamellar martensite (M1) was coarsened, and the amount of M1 decreased. Moreover, the amounts of lath-like retained austenite (RA) decreased and the amounts of bulky austenite increased. The tested steel partitioned at 260 °C had relatively greater fractions of RA, in which there were sufficient contents of carbon diffused from M1. Therefore, the test steel partitioned at 260 °C showed fine comprehensive mechanical properties. The combination of tensile strength and elongation reached 30.3 GPa.%, and its work-hardening plateau was the longest, showing excellent ductility as it had sufficient fractions of the retained austenite with good stability.
Repair Reliability Analysis of a Special-Shaped Epoxy Steel Sleeve for Low-Strength Tee Pipes
Authors: Cao Jun , Jia Haidong , Ma Weifeng , Wang Ke , Yao Tian , Ren Junjie , Nie Hailiang , Liang Xiaobin , Dang Wei
Published: December 2022

Ensuring the safe operation of pipe fittings in a natural gas station is critical. The irregular shape of the tee easily leads to uneven mechanical properties in the manufacturing process. The strength of the tee may be lower than the requirements due to its unqualified heat-treatment process. As a result, selecting a reliable way of repairing low-strength tee pipes is a pressing concern. To repair the low-strength tee pipes, a special-shaped epoxy steel sleeve (SSESS) was designed. To optimize the critical design parameters, the SSESS design criteria were established. Following that, the SSESS repair testing was conducted using the optimized design parameters. The SSESS repair reliability was proved using hydraulic burst testing with strain monitoring and simulations of unrepaired and SSESS repaired tees. The result indicated that the SSESS repaired tee’s yielding and burst pressure increased, demonstrating its repair reliability. Furthermore, the SSESS repair revealed the stress and strain concentration decrease law.
AlSi10Mg/AlN Interface Grain Structure after Laser Powder Bed Fusion
Authors: Pelevin Ivan A. , Ozherelkov Dmitriy Yu. , Nalivaiko Anton Yu. , Bodyakova Anna I. , Chernyshikhin Stanislav V. , Zotov Boris O. , Korshunov Andrey V. , Gromov Alexander A.
Published: December 2022

Details and features of the grain structure near the interface region between the AlN ceramic phase and AlSi10Mg matrix after the laser powder bed fusion (LPBF) were investigated. Aluminum nitride particles were obtained through self-propagating high-temperature synthesis and mechanically mixed with aluminum matrix powder. Optimization of the LPBF process parameters resulted in synthesized material free of pores and other defects. Optical microscopy analysis of etched cross-section and more detailed EBSD analysis revealed regions with relatively coarse grains at melting pool boundaries and fine grains in the melt pool core and near the AlN particles. Moreover, a pronounced orientation of fine elongated matrix grains towards the center of the ceramic particle was obtained. The such formed microstructure is attributed to directional heat sink during crystallization due to the higher thermal conductivity of aluminum nitride compared to the AlSi10Mg matrix. On the contrary, poor wettability of AlN by melt partly prevented the formation of such features, thus a combination of these factors determines the final microstructure of the interface in the resulting material.
Lactic Acid Bacteria Improve the Photoprotective Effect via MAPK/AP-1/MMP Signaling Pathway on Skin Fibroblasts
Authors: Park Jeong-Yong , Lee Ji Yeon , Kim YongGyeong , Kang Chang-Ho
Published: December 2022

Ultraviolet B (UVB) exposure causes a breakdown of collagen, oxidative stress, and inflammation. UVB activates mitogen-activated protein kinase (MAPK), activator protein-1 (AP-1), and matrix metalloproteinases (MMPs). In this study, we evaluated 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical scavenging activity and the photoprotective effect of lactic acid bacteria LAB strains, including Lactobacillus, Bifidobacterium, and Streptococcus genera in UVB-exposed skin fibroblasts. Nine LAB strains displayed antioxidant activity by regulating superoxide dismutase in UVB-exposed skin fibroblasts. Four LAB strains (MG4684, MG5368, MG4511, and MG5140) recovered type I procollagen level by inhibiting MMPs, MAPK, and AP-1 protein expression. Additionally, these four strains reduced the expression of proinflammatory cytokines by inhibiting oxidative stress. Therefore, L. fermentum MG4684, MG5368, L. rhamnosus MG4511, and S. thermophilus MG5140 are potentially photoprotective.
The Origin of Carbonate Components in Carbonate Hosted Pb-Zn Deposit in the Sichuan-Yunnan-Guizhou Pb-Zn Metallogenic Province and Southwest China: Take Lekai Pb-Zn Deposit as an Example
Authors: He Zhiwei , Li Bo , Wang Xinfu , Xiao Xianguo , Wan Xin , Wei Qingxi
Published: December 2022

The Lekai lead–zinc (Pb-Zn) deposit is located in the northwest of the Sichuan–Yunnan–Guizhou (SYG) Pb-Zn metallogenic province, southwest China. Even now, the source of the metallogenic fluid of Pb-Zn deposits in the SYG Pb-Zn metallogenic province has not been recognized. Based on traditional lithography, rare earth elements (REEs), and carbon–oxygen (C–O) isotopes, this work uses the magnesium (Mg) isotopes of hydrothermal carbonate to discuss the fluid source of the Lekai Pb-Zn deposit and discusses the fractionation mechaism of Mg isotopes during Pb-Zn mineralization. The REE distribution patterns of hydrothermal calcite/dolomite are similar to that of Devonian sedimentary carbonate rocks, which are all present steep right-dip type, indicating that sedimentary carbonate rocks may be serve as the main source units of ore-forming fluids. The C–O isotopic results of hydrothermal dolomite/calcite and the δ13CPDB–δ18 OSMOW diagram show that dolomite formation is closely related to the dissolution of marine carbonate rocks, and calcite may be affected to some extent by basement fluid. The Mg isotopic composition of dolomite/calcite ranges from −3.853‰ to −1.358‰, which is obviously lighter than that of chondrites, mantle, or seawater and close to that of sedimentary carbonate rock. It shows that the source of the Mg element in metallogenic fluid of Lekai Pb-Zn deposit may be sedimentary carbonate rock rather than mantle, chondrites, or seawater. In addition, the mineral phase controls the Mg isotope fractionation of dolomite/calcite in the Lekai Pb-Zn deposit. Based on the geological, mineralogical, and hydrothermal calcite/dolomite REE, C–O isotope, and Mg isotope values, this work holds that the mineralization of the Lekai Pb-Zn deposit is mainly caused by basin fluids, influenced by the basement fluids; the participation of basement fluids affects the scale and grade of the deposit.
Fine Structure and the Huge Zero-Field Splitting in Ni2+ Complexes
Authors: Georgiev Miroslav , Chamati Hassan
Published: December 2022

We perform a thorough study of the ground state magnetic properties of nickel-based 3d8 complexes. This includes an in-depth analysis of the contribution of the crystal field, spin exchange and spin–orbit interactions to the ground state magnetic properties. Of particular interest to the current investigation are the presence and occurrence of non-trivial zero-field splitting. The study focuses on the cases of Ni2+ ideal octahedral, trigonal bipyramidal, square planar and tetrahedral geometries. We provide results for the complete energy spectrum, the fine structure related to the ground state and the second set of excited states, low-field magnetic susceptibility and magnetization. In addition, we examine the zero-field fine structure in square pyramidal, trigonal pyramidal and trigonal planar complexes. The obtained results unequivocally show that a moderate or highly coordinated 3d8 complex can neither exhibit spin–orbit-driven large and giant magnetic anisotropy nor a huge zero-field splitting. Moreover, in the trigonal bipyramidal coordination, a fine structure associated to the ground state cannot result from the spin-orbit coupling alone.
Analysis of Volatile Compounds from Different Parts of Houttuynia cordata Thunb.
Authors: Lin Chen-Hsiang , Chao Louis Kuoping , Lin Li-Yun , Wu Chin-Sheng , Chu Lee-Ping , Huang Chien-Hsueh , Chen Hsin-Chun
Published: December 2022

Houttuynia cordata Thunb. is a medicinal and edible plant that has been commonly used in traditional Chinese medicine since ancient times. This study used headspace solid-phase microextraction (HS-SPME) and direct injection, combined with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), to identify the volatile compounds in H. cordata. Extraction from different parts of the plant using different extraction techniques for the identification of volatile compounds were determined. A total of 93 volatile components were analyzed in the leaves, stems, rhizomes, and whole plant samples of H. cordata. The leaves contained more (Z)-3-hexenal, β-myrcene, (Z)-β-ocimene, and (4E,6E)-allo-ocimene; the stems contained more geranyl acetate and nerolidol; and rhizomes contained more α-pinene, β-pinene, limonene, 2-undecanone, and decanoyl acetaldehyde. Among them, the essential oil extracted by HS-SPME could produce more monoterpenes, while direct injection could obtain higher contents of aliphatic ketones, terpene esters, sesquiterpenes, and was more conducive to the extraction of 2-undecanone and decanoyl acetaldehyde.
Thermal, Mechanical and Dielectric Properties of Polyimide Composite Films by In-Situ Reduction of Fluorinated Graphene
Authors: Zhang Yuyin , Hu Tian , Hu Rubei , Jiang Shaohua , Zhang Chunmei , Hou Haoqing
Published: December 2022

Materials with outstanding mechanical properties and excellent dielectric properties are increasingly favored in the microelectronics industry. The application of polyimide (PI) in the field of microelectronics is limited because of the fact that PI with excellent mechanical properties does not have special features in the dielectric properties. In this work, PI composite films with high dielectric properties and excellent mechanical properties are fabricated by in-situ reduction of fluorinated graphene (FG) in polyamide acid (PAA) composites. The dielectric permittivity of pure PI is 3.47 and the maximum energy storage density is 0.664 J/cm3 at 100 Hz, while the dielectric permittivity of the PI composite films reaches 235.74 under the same conditions, a 68-times increase compared to the pure PI, and the maximum energy storage density is 5.651, a 9-times increase compared to the pure PI films. This method not only solves the problem of the aggregation of the filler particles in the PI matrix and maintains the intrinsic excellent mechanical properties of the PI, but also significantly improves the dielectric properties of the PI.
Donor–Acceptor Complexes of (5,10,15,20-Tetra(4-methylphenyl)porphyrinato)cobalt(II) with Fullerenes C60: Self-Assembly, Spectral, Electrochemical and Photophysical Properties
Authors: Bichan Nataliya G. , Ovchenkova Ekaterina N. , Mozgova Varvara A. , Ksenofontov Alexander A. , Kudryakova Nadezhda O. , Shelaev Ivan V. , Gostev Fedor E. , Lomova Tatyana N.
Published: December 2022

The noncovalent interactions of (5,10,15,20-tetra(4-methylphenyl)porphinato)cobalt(II) (CoTTP) with C60 and 1-N-methyl-2-(pyridin-4-yl)-3,4-fullero[60]pyrrolidine (PyC60) were studied in toluene using absorption and fluorescence titration methods. The self-assembly in the 2:1 complexes (the triads) (C60)2CoTTP and (PyC60)2CoTTP was established. The bonding constants for (C60)2CoTTP and (PyC60)2CoTTP are defined to be (3.47 ± 0.69) × 109 and (1.47 ± 0.28) × 1010 M−2, respectively. 1H NMR, IR spectroscopy, thermogravimetric analysis and cyclic voltammetry data have provided very good support in favor of efficient complex formation in the ground state between fullerenes and CoTTP. PyC60/C60 fluorescence quenching in the PyC60/C60–CoTTP systems was studied and the fluorescence lifetime with various CoTTP additions was determined. The singlet oxygen quantum yield was determined for PyC60 and the intensity decrease in the 1O2 phosphorescence for C60 and PyC60 with the CoTTP addition leading to the low efficiency of intercombination conversion for the formation of the 3C60* triplet excited state was found. Using femtosecond transient absorption measurements in toluene, the photoinduced electron transfer from the CoTTP in the excited singlet state to fullerene moiety was established. Quantum chemical calculations were used for the determination of molecular structure, stability and the HOMO/LUMO energy levels of the triads as well as to predict the localization of frontier orbitals in the triads.
Solid Sampling Pyrolysis Adsorption-Desorption Thermal Conductivity Method for Rapid and Simultaneous Detection of N and S in Seafood
Authors: Shang Derong , Gu Wenyan , Zhai Yuxiu , Ning Jinsong , Mao Xuefei , Sheng Xiaofeng , Zhao Yanfang , Ding Haiyan , Kang Xuming
Published: December 2022

In this work, a rapid method for the simultaneous determination of N and S in seafood was established based on a solid sampling absorption-desorption system coupled with a thermal conductivity detector. This setup mainly includes a solid sampling system, a gas line unit for controlling high-purity oxygen and helium, a combustion and reduction furnace, a purification column system for moisture, halogen, SO2, and CO2, and a thermal conductivity detector. After two stages of purging with 20 s of He sweeping (250 mL/min), N2 residue in the sample-containing chamber can be reduced to <0.01% to improve the device’s analytical sensitivity and precision. Herein, 100 s of heating at 900 °C was chosen as the optimized decomposition condition. After the generated SO2, H2O, and CO2 were absorbed by the adsorption column in turn, the purification process executed the vaporization of the N-containing analyte, and then N2 was detected by the thermal conductivity cell for the quantification of N. Subsequently, the adsorbed SO2 was released after heating the SO2 adsorption column and then transported to the thermal conductivity cell for the detection and quantification of S. After the instrumental optimization, the linear range was 2.0–100 mg and the correlation coefficient (R) was more than 0.999. The limit of detection (LOD) for N was 0.66 μg and the R was less than 4.0%, while the recovery rate ranged from 95.33 to 102.8%. At the same time, the LOD for S was 2.29 μg and the R was less than 6.0%, while the recovery rate ranged from 92.26 to 105.5%. The method was validated using certified reference materials (CRMs) and the measured N and S concentrations agreed with the certified values. The method indicated good accuracy and precision for the simultaneous detection of N and S in seafood samples. The total time of analysis was less than 6 min without the sample preparation process, fulfilling the fast detection of N and S in seafood. The establishment of this method filled the blank space in the area of the simultaneous and rapid determination of N and S in aquatic product solids. Thus, it provided technical support effectively to the requirements of risk assessment and detection in cases where supervision inspection was time-dependent.
Development of a Protein-Rich By-Product by 23 Factorial Design: Characterization of Its Nutritional Value and Sensory Analysis
Authors: dos Santos Thamara R. , dos Santos Melo Jakcline , dos Santos Alysson V. , Severino Patrícia , Lima Álvaro S. , Souto Eliana B. , Zielińska Aleksandra , Cardoso Juliana C.
Published: December 2022

The aim of this study was the development of a cereal bar based on bee pollen (BP), honey (H), and flour by-products (peel passion fruit flour—PPFF), generating an innovative product. BP is a protein-rich ingredient and can be used in the composition of cereal bars. PPFF is a by-product rich in fibers. The formulations were developed using a 23 factorial design with four replicates in the center point, studying the sensory analysis as a response variable. The texture and nutritional parameters were performed for the optimal formulation. BP showed ca. 15% of protein. The final formulation (10.35% BP, 6.8% PPFF, and 25% H) presented 22.2% moisture, 1.8% ash, 0.4% total fat, 3.0% fiber, 63.1% carbohydrates, and 74.0 Kcal/25 g. The sensory analysis presented valued around 7 (typical of a traditional bar). Regarding the possibility of purchasing the product, 51% of the panelists said they would probably buy the developed product. The formulated cereal bar had a similar composition as those already marketed. Moreover, it can be considered a source of fiber and is sensory acceptable. This approach opens up new opportunities for developing nutritional and functional foodstuff with improved sensorial aspects.