bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodiesel Production Using Lithium Metasilicate Synthesized from Non-Conventional Sources
Authors: Coutino-Gonzalez Eduardo , Ávila-Gutiérrez Mario , Hernández-Palomares Arnold , Olvera Lilian I. , Rodríguez-Valadez Francisco J. , Espejel-Ayala Fabricio
Published: September 2022

A facile and versatile process to produce lithium metasilicate (Li2SiO3) from non-conventional silicon sources (two different sand sources from the central area of México) was developed. The synthesis protocol based on a solid-state reaction followed by a hydrothermal treatment resulted in highly pure lithium metasilicate, as corroborated by XRD, SEM-EDS, and XPS analysis. Furthermore, lithium metasilicate was used as a heterogeneous catalyst for biodiesel production from soybean oil, where conversion yields were compared according to the silicon source used (based on chemical purity, stability, and yield efficiency). The best performing metasilicate material displayed a maximum of 95.5% of biodiesel conversion under the following conditions: 180 min, 60 °C, 5% catalyst (wt./wt., catalyst-to-oil), and 18:1 (methanol:oil). This contribution opens up alternatives for the production of lithium metasilicate using non-conventional precursors and its use as an alternative catalyst in biodiesel production, displaying better chemical stability against humidity than conventional heterogeneous catalysts.
Simulation of the Refractive Index Variation and Validation of the Form Deviation in Precisely Molded Chalcogenide Glass Lenses (IRG 26) Considering the Stress and Structure Relaxation
Authors: Jiang Cheng , Tovar Carlos Marin , Staasmeyer Jan-Helge , Friedrichs Marcel , Grunwald Tim , Bergs Thomas
Published: September 2022

Precise infrared (IR) optics are core elements of infrared cameras for thermal imaging and night vision applications and can be manufactured directly or using a replicative process. For instance, precision glass molding (PGM) is a replicative manufacturing method that meets the demand of producing precise and accurate glass optics in a cost-efficient manner. However, several iterations in the PGM process are applied to compensate the induced form deviation and the index drop after molding. The finite element method (FEM) is utilized to simulate the thermomechanical process, predicting the optical properties of molded chalcogenide lenses and thus preventing costly iterations. Prior to FEM modelling, self-developed glass characterization methods for the stress and structure relaxation of chalcogenide glass IRG 26 are implemented. Additionally, a ray-tracing method is developed in this work to calculate the optical path difference (OPD) based on the mesh structure results from the FEM simulation. The developed method is validated and conducted during the production of molded lenses.
Investigation of the Surface Treatment Process of AISI 304 Stainless Steel by Centrifugal Disc Finishing with the Use of an Active Workpiece Holder
Authors: Juniewicz Mateusz , Plichta Jarosław , Sutowska Marzena , Łukianowicz Czesław , Kukiełka Krzysztof , Zawadka Wojciech
Published: September 2022

This article presents the results of experimental studies of the centrifugal disc finishing (CDF) process of 304 steel elements with the use of an active workpieces holder, that allows workpieces for additional rotational and oscillation movements. The main aim of the research was to evaluate the mechanism of formation of the surface texture and to assess the intensity and effectiveness of the machining process. It is shown that additional movements of the workpiece significantly affect the formation of the machining traces generated by the elementary phenomena of micro-cutting, scratching, grooving, etc. As a result, these combined and complex interactions lead to the formation of the surface topography of the workpieces. Based on the research results, it can be concluded that the use of an active workpiece holder in the CDF process allows changes in the intensity of the machining process. Moreover, the active holder allows modification of the surface smoothing process. The intensity of the treatment process depends primarily on the location of the workpiece holder in the appropriate energy area of the work charge. On the other hand, the efficiency of the workpiece surface smoothing depends on the parameters of the oscillation and rotational movements of the workpiece mounted in the active holder. The presented research results show that the use of an active holder, enabling rotation and oscillation of the workpiece, may lead to a more effective use of smoothing processes in CDF machines. The analysis of the results shows that the values of the Sdr and Sa parameters are more strongly dependent on the vibration frequency and increase with its increasing frequency. This is undoubtedly the result of the concentration of smoothing marks on the smoothed surface. However, with regard to the rotational speed of the object, this relationship is non-monotonic, and its greatest influence occurs at its intermediate values. It follows that this activity does not have a significant impact on the generation of the number of smoothing marks and the degree of their concentration. The research methodology proposed in the work allows the initial determination of the dependence of the results of the CDF process on the machining parameters, including the parameters of the active holder. This methodology can also be used for machining materials other than AISI 304 steel.
Development of Biodegradable PLA/PBAT-Based Filaments for Fertilizer Release for Agricultural Applications
Authors: da Silva Thyago Camelo Pereira , Fortes Allef Gabriel da Silva , de Abreu Iago Rodrigues , de Carvalho Laura Hecker , de Almeida Yeda Medeiros Bastos , Alves Tatianny Soares , Barbosa Renata
Published: September 2022

The aim of this work was to produce filaments of PLA/PBAT and NPK fertilizer adsorbed on organophilized bentonite intended for application in the prototyping of biodegradable agricultural artifacts in 3D printing, using the Fused Deposition Modeling (FDM) technique. This is the first time that we have reported this composite for a 3D printing approach. Systems containing PLA/PBAT, organobentonite and NPK were initially processed in an internal mixer and later extruded as filaments in a single-screw extruder. The prototypes were printed by FDM. Structural, morphological and thermal properties, as well as NPK releasing, were investigated. The results suggest that exfoliated and/or intercalated nanocomposites were obtained by the organoclay addition to the PLA/PBAT blend. The morphological analysis revealed a good surface quality of the impressions. Systems containing organobentonite released approximately 22% less fertilizer in 24 h compared to the systems without organobentonite. This difference is due to the higher concentration of nanoparticles that generate more barriers to the diffusion of NPK. The release data for these systems had a better fit to the kinetic model of Korsmeyer-Peppas. Thus, studied filaments have the potential to retard the release of fertilizer and are suitable for further development of structures for agricultural applications by FDM.
Hot Deformation Behavior and Microstructure Evolution of a Novel Al-Zn-Mg-Li-Cu Alloy
Authors: Wu Shuaishuai , Zhu Baohong , Jiang Wei , Qiu Haochen , Guo Yang
Published: September 2022

Lightweight structural alloys have broad application prospects in aerospace, energy, and transportation fields, and it is crucial to understand the hot deformation behavior of novel alloys for subsequent applications. The deformation behavior and microstructure evolution of a new Al-Zn-Mg-Li-Cu alloy was studied by hot compression experiments at temperatures ranging from 300 °C to 420 °C and strain rates ranging from 0.01 s−1 to 10 s−1. The as-cast Al-Zn-Mg-Li-Cu alloy is composed of an α-Al phase, an Al2Cu phase, a T phase, an η phase, and an η′ phase. The constitutive relationship between flow stress, temperature, and strain rate, represented by Zener–Hollomon parameters including Arrhenius terms, was established. Microstructure observations show that the grain size and the fraction of DRX increases with increasing deformation temperature. The grain size of DRX decreases with increasing strain rates, while the fraction of DRX first increases and then decreases. A certain amount of medium-angle grain boundaries (MAGBs) was present at both lower and higher deformation temperatures, suggesting the existence of continuous dynamic recrystallization (CDRX). The cumulative misorientation from intragranular to grain boundary proves that the CDRX mechanism of the alloy occurs through progressive subgrain rotation. This paper provides a basis for the deformation process of a new Al-Zn-Mg-Li-Cu alloy.
Gradient Structure of the Transfer Layer in Friction Stir Welding Joints
Authors: Eliseev Alexander , Osipovich Kseniya , Fortuna Sergei
Published: September 2022

Despite a thirty-year history of friction stir welding, some basic aspects still remain unclear. In particular, questions arise about mass transfer and the formation of transfer layers. It is not clear why there are visible boundaries between the layers. The structure of the transfer layer has been studied very little. These issues are not considerably important from the viewpoint of obtaining high-quality welds, but they can help to a better understanding of the welding process. In this paper, the structural evolution in the transfer layer of 2024 aluminum alloy welds produced under various loads and with ultrasonic assistance is discussed. Structural studies revealed a gradient structure in the transfer layer. The grain size, the volume fraction and size of large intermetallic particles decrease towards the center of the layer, while the volume fraction of semi-coherent secondary particles increases. As a result, the microhardness is higher in the center of the transfer layer. A mass transfer mechanism is proposed based on the experimental results: the rotating tool transfers the material back layer by layer during welding; the contacting layers rub against each other and generate heat, due to which the structure at the layer boundary changes. With increasing axial force on the tool, the grain size also increases due to higher heat generation. Ultrasound has almost no effect on the grain structure, but it reduces the volume fraction and size of secondary particles and microhardness.
Effect of Phosphorus Slag Admixture on the Properties and Hydration Mechanism of Circulating Fluidized Bed Fly Ash-Based Multi-Solid Waste Cementitious Material
Authors: Zhang Wei , Wei Chao , Liu Xiaoming , Zhang Zengqi
Published: September 2022

This research aims to reveal the effect of phosphorus slag (PS) admixtures on the properties and hydration mechanism of circulating fluidized bed fly ash (CFA)-based multi-solid waste cementitious material (CWM). The results indicate that PS as an admixture is more helpful for improving the performance of CWM systems compared with blast furnace slag with a high specific surface area (HBFS) and gasification slag (GS). In this work, CWM2 is prepared with 30 wt.% CFA, 10 wt.% red mud (RM), 20 wt.% blast furnace slag (BFS), 10 wt.% PS, and 30 wt.% cement clinker (CC). The compressive strength and expansion value of CWM2 are the optimal (51.15 MPa and 0.70 mm) when the mass ratio of (Ca + Na)/(Si + Al) is 0.84, which can meet the requirements of 42.5 fly ash Portland cement. In addition, the polymerization degree of CWM2-28 days is the optimum (51.57%) because [PO4] and [SiO4] combine to improve its polymerization structure. The main hydration products are C-S-H gel, C/N-A-S-H gel, and ettringite in CWM, which are conducive to improve the compactness of the micromorphology. In addition, the consolidation of Na, As, Cd, and Hg is promoted in CWM2 by physical encapsulation and charge balance, which meet the drinking water requirements of the World Health Organization (WHO). Therefore, this work provides a new idea for the application of PS as an admixture in CFA-based multi-solid waste cementitious material.
Experimental Investigation of Sand Subjected to High Stress Levels in Wet and Dry Conditions
Authors: Youssef Shadi , Accary Abdallah , Dano Christophe , Malecot Yann
Published: September 2022

This work aimed to understand the mechanical behavior of siliceous and calcareous sand materials under uniaxial confined compression loading at high stress levels. For this purpose, a series of quasi-oedometric compression tests were conducted on sand materials, to examine the effects of grain size, nature, and moisture contents on the soil crushability and the compression behavior, using an upgraded thick pressure vessel device that can reach mean stress up to 500 MPa. All samples were prepared using an aspect ratio of 1:1 (diameter: height), placed inside a high strength steel vessel, and compressed at a uniform axial displacement rate of 5 µm/s. The vessel is instrumented with multiple strain gauges allowing for the characterization of the hydrostatic and deviatoric behavior of each test. The results of quasi-oedometric tests, conducted on these types of sand, up to a passive confinement of 500 MPa, show that particle breakage is enhanced by the presence of water. It was noticed that, for siliceous sand, smaller particles break more than larger particles, and that the calcareous grains manifest a rapid response to axial stress compared to siliceous sand. Testing various soil properties shows a great potential to better characterize the sensitivity to breakage of soils. Lastly, a post-mortem analysis of samples before and after testing, using the X-ray micro-tomography technique, was applied to study the mechanical damage of sand specimens.
Microstructure and Properties of ZrB2-SiC Reinforced Copper Matrix Composite Coatings Prepared by Laser Cladding
Authors: Zhao Yuehong , Zhan Zaiji , Lv Xiangzhe , Cao Haiyao
Published: September 2022

With the use of electrolytic Cu powder, Zr powder, Si powder and nickel-coated B4C powder as cladding powders, in-situ synthesized ZrB2-SiC reinforced copper matrix composite coatings were prepared by laser cladding on the surface of the copper substrate to improve the surface hardness and wear resistance. Under the condition of a laser energy density at 60 kJ/cm2, the macroscopic surface of the composite coating was continuously flat. The microstructure and phase of the cladding coating were analyzed by means of XRD and SEM. The reinforcements with nano-scale particle and micron-scale needle-like structures were in-situ synthesized in the cladding coating, and the content of the reinforcement phase decreased slightly from the coating surface to the substrate. The phase analysis results showed that the reinforcements included ZrB2 and SiC. When the content of the reinforcement was increased to 30 wt%, microhardness also increased from 48 HV0.2 to 309 HV0.2, which was about 5.6 times that of the copper matrix. The wear resistance of the composite coatings was characterized by current-carrying wear tests. By keeping the sliding speed and load constant, the wear rate decreased with an increase in the reinforcement content, and the wear mechanism changed from adhesive wear to abrasive wear. The wear rate of the composite coating with the current was higher than that without the current due to its electric ablation and high temperature.
An Industrial Blockchain-Based Multi-Criteria Decision Framework for Global Freight Management in Agricultural Supply Chains
Authors: Nakandala Dilupa , Tsang Yung Po , Lau Henry , Lee Carman Ka Man
Published: September 2022

In view of increasing supply chain disruption events, for example the China–United States trade war, the COVID-19 pandemic, and the Russia–Ukraine war, the complexity and dynamicity of global freight management keeps increasing. To build a resilient and sustainable supply chain, industrial practitioners are eager to systematically revamp the freight management decision process related to the selection of carriers, shipping lanes, and third-party logistics service providers. Therefore, this study aims at strengthening decision-making capabilities for global freight management, in which an industrial blockchain-based global freight decision framework (IB-GFDF) is proposed to incorporate consortium blockchain technology with the Bayesian best-worst method. Through the blockchain technology, pairwise comparisons can be conducted over the international freight network in a decentralized and immutable manner, and thus, a secure and commonly agreed-on pairwise comparison dataset is acquired. Subsequently, the pairwise comparison dataset with multi-stakeholder opinions is analyzed using the Bayesian best-worst method in order to prioritize the selection decision criteria related to carriers, shipping lanes, and 3PL service providers for global freight management. To verify the methodological feasibility, a case study of an Australian agricultural supply chain firm was conducted to support the development end-to-end (E2E) supply chain solutions originated from Australia. It was found that port infrastructure, ports of call and communication effectiveness were the major criteria for the selection decision, which can be emphasized in future global freight collaboration. In addition, an immutable and append-only record of pairwise comparisons can be established to support the visibility of time-varying stakeholders’ preferences.
Text Mining of User-Generated Content (UGC) for Business Applications in E-Commerce: A Systematic Review
Authors: Li Shugang , Liu Fang , Zhang Yuqi , Zhu Boyi , Zhu He , Yu Zhaoxu
Published: September 2022

In the Web2.0 era, user-generated content (UGC) provides a valuable source of data to aid in understanding consumers and driving intelligent business. Text mining techniques, such as semantic analysis and sentiment analysis, help to extract meaningful information embedded in UGC. However, research on text mining of UGC for e-commerce business applications involves interdisciplinary knowledge, and few studies have systematically summarized the research framework and application directions of related research in this field. First, based on e-commerce practice, in this study, we derive a general framework to summarize the mainstream research in this field. Second, widely used text mining techniques are introduced, including semantic and sentiment analysis. Furthermore, we analyze the development status of semantic analysis in terms of text representation and semantic understanding. Then, the definition, development, and technical classification of sentiment analysis techniques are introduced. Third, we discuss mainstream directions of text mining for business applications, ranging from high-quality UGC detection and consumer profiling, to product enhancement and marketing. Finally, research gaps with respect to these efforts are emphasized, and suggestions are provided for future work. We also provide prospective directions for future research.
Mathematical Model of Pancreatic Cancer Cell Dynamics Considering the Set of Sequential Mutations and Interaction with the Immune System
Authors: Bratus Alexander S. , Leslie Nicholas , Chamo Michail , Grebennikov Dmitry , Savinkov Rostislav , Bocharov Gennady , Yurchenko Daniil
Published: September 2022

Pancreatic cancer represents one of the difficult problems of contemporary medicine. The development of the illness evolves very slowly, happens in a specific place (stroma), and manifests clinically close to a final stage. Another feature of this pathology is a coexistence (symbiotic) effect between cancer cells and normal cells inside stroma. All these aspects make it difficult to understand the pathogenesis of pancreatic cancer and develop a proper therapy. The emergence of pancreatic pre-cancer and cancer cells represents a branching stochastic process engaging populations of 64 cells differing in the number of acquired mutations. In this study, we formulate and calibrate the mathematical model of pancreatic cancer using the quasispecies framework. The mathematical model incorporates the mutation matrix, fineness landscape matrix, and the death rates. Each element of the mutation matrix presents the probability of appearing as a specific mutation in the branching sequence of cells representing the accumulation of mutations. The model incorporates the cancer cell elimination by effect CD8 T cells (CTL). The down-regulation of the effector function of CTLs and exhaustion are parameterized. The symbiotic effect of coexistence of normal and cancer cells is considered. The computational predictions obtained with the model are consistent with empirical data. The modeling approach can be used to investigate other types of cancers and examine various treatment procedures.
Derivative for Functions f:G→H, Where G Is a Metric Divisible Group
Authors: Granada Díaz Héctor Andrés , Trujillo Simeón Casanova , Hoyos Fredy E.
Published: September 2022

In this paper, a derivative for functions f:G→H, where G is any metric divisible group and H is a metric Abelian group with a group metric, is defined. Basic differentiation theorems are stated and demonstrated. In particular, we obtain the Chain Role.
Preface to the Special Issue on “Advances in Differential Dynamical Systems with Applications to Economics and Biology”
Authors: Kaslik Eva , Neamţu Mihaela , Rădulescu Anca
Published: September 2022

In recent research on natural processes, mathematical modeling has become a very useful tool [...]
Reachset Conformance and Automatic Model Adaptation for Hybrid Systems
Authors: Roehm Hendrik , Rausch Alexander , Althoff Matthias
Published: September 2022

Model-based verification uses a model to reason about the correctness of a real system. This requires the model and the system to be conformant, such that verification results on the model can be transfered to the real system. Especially for hybrid systems, which combine discrete and continuous behavior, defining and checking conformance is a difficult task. In this work, we present reachset conformance for hybrid systems that transfers safety properties from a model to the real system. We show how a model can be adapted to be conformant to measurements of a real system and demonstrate this for a real autonomous vehicle. The obtained reachset conformant model can be used for the verification of safety-critical properties, such as collision avoidance.
Remimazolam for General Anesthesia in a Patient with Severe Aortic Stenosis Undergoing High-Risk Surgery: A Case Report
Authors: Kim Bo Rim , Kim Moo Soo , Lee Jae Hak , Lee Do Yeop , Kim Hye-bin , Oh Seok Kyeong , Kim Heezoo
Published: September 2022

High-risk surgeries for patients with severe aortic stenosis (AS) are challenging for anesthesiologists and can result in hemodynamic deterioration and even mortality. We describe a case in which remimazolam was used to induce and maintain general anesthesia for a high-risk, noncardiac surgery accompanied by ongoing bleeding. An 86-year-old man with severe AS was scheduled to undergo proximal gastrectomy due to ongoing gastrointestinal bleeding and severe anemia. Remimazolam, a novel, ultra-short-acting benzodiazepine, was administered along with remifentanil for the induction and maintenance of general anesthesia. Throughout the anesthetic process, the patient’s cardiac index and systemic vascular resistance were well preserved without any vasopressor support. Remimazolam seems to have possible effectiveness as a relatively safe agent for the induction and maintenance of general anesthesia in patients with severe AS who are undergoing high-risk, noncardiac surgery with bleeding.
Forward Osmosis Membranes: The Significant Roles of Selective Layer
Authors: Tian Miao , Ma Tao , Goh Kunli , Pei Zhiqiang , Chong Jeng Yi , Wang Yi-Ning
Published: September 2022

Forward osmosis (FO) is a promising separation technology to overcome the challenges of pressure-driven membrane processes. The FO process has demonstrated profound advantages in treating feeds with high salinity and viscosity in applications such as brine treatment and food processing. This review discusses the advancement of FO membranes and the key membrane properties that are important in real applications. The membrane substrates have been the focus of the majority of FO membrane studies to reduce internal concentration polarization. However, the separation layer is critical in selecting the suitable FO membranes as the feed solute rejection and draw solute back diffusion are important considerations in designing large-scale FO processes. In this review, emphasis is placed on developing FO membrane selective layers with a high selectivity. The effects of porous FO substrates in synthesizing high-performance polyamide selective layer and strategies to overcome the substrate constraints are discussed. The role of interlayer in selective layer synthesis and the benefits of nanomaterial incorporation will also be reviewed.
Cardo Polybenzimidazole (PBI-O-PhT) Based Membrane Reinforced with m-polybenzimidazole Electrospun Nanofiber Mat for HT-PEM Fuel Cell Applications
Authors: Ponomarev Igor I. , Skupov Kirill M. , Modestov Alexander D. , Lysova Anna A. , Ponomarev Ivan I. , Vtyurina Elizaveta S.
Published: September 2022

The further development of high temperature polymer electrolyte membrane (HT-PEM) fuel cells largely depends on the improvement of all components of the membrane–electrode assembly (MEA), especially membranes and electrodes. To improve the membrane characteristics, the cardo-polybenzimidazole (PBI-O-PhT)-based polymer electrolyte complex doped with phosphoric acid is reinforced using an electrospun m-PBI mat. As a result, the PBI-O-PhT/es-m-PBInet · nH3PO4 reinforced membrane is obtained with hydrogen crossover values (~0.2 mA cm−2 atm−1), one order of magnitude lower than the one of the initial PBI-O-PhT membrane (~3 mA cm−2 atm−1) during HT-PEM fuel cell operation with Celtec®P1000 electrodes at 180 °C. Just as importantly, the reinforced membrane resistance was very close to the original one (65–75 mΩ cm2 compared to ~60 mΩ cm2). A stress test that consisted of 20 start–stops, which included cooling to the room temperature and heating back to 180 °C, was applied to the MEAs with the reinforced membrane. More stable operation for the HT-PEM fuel cell was shown when the Celtec®P1000 cathode (based on carbon black) was replaced with the carbon nanofiber cathode (based on the pyrolyzed polyacrylonitrile electrospun nanofiber mat). The obtained data confirm the enhanced characteristics of the PBI-O-PhT/es-m-PBInet · nH3PO4 reinforced membrane.
Production Scheduling Optimization during Thermoforming of Ring Forgings Based on Genetic Algorithms
Authors: Chen Yizhe , Xie Beichen , Ma Huijuan , Wang Hui , Zhou Yulong , Chen Jie , Hua Lin
Published: September 2022

In the aerospace industry, many important components are made of ring forgings with characteristics of multi-variety and multi-batch. Such components have many steps and complex parameters in the thermoforming process. The process orders are dynamic and time-varying, and, thus, optimizing the total production time and energy consumption is difficult. To solve the mentioned troublesome and time-consuming problem, this work transformed the workpiece’s required heating temperature and time index into the furnace temperature change and holding time index. Based on a genetic algorithm, an integrated production scheduling optimization of ring forging heating and model forming was established. The genetic algorithm for model improvement was optimized. The optimization objective was changed by using different fitness calculation methods. A multi-time simulation algorithm was designed to calculate each heating furnace’s time and furnace temperature. The proposed optimization method was used for a thermoforming process of ring forgings. When the optimization objective was designed to consider energy consumption and time consumption comprehensively, the average time saving was 6.93%, and the average energy saving was 12.99%. When the optimization objective was designed to prioritize energy consumption, the average time saving was 3.89%, and the average energy saving was 16.53%. When the optimization objective was designed to prioritize time consumption, the average time saving was 10.35%, and the average energy saving was 10.63%. Using the scheduling results for production, compared with the practical factory data, the errors in the simulation time and energy consumption were 2.4% and 1.6%. The results show that the scheduling efficiency of integrated thermoforming production is significantly improved by using this optimization model, and the simulation results have high reliability. The energy consumption of orders is greatly reduced, and the total production time is greatly shortened.
Simulating Diffusion Induced Grain Boundary Migration in Binary Fe–Zn
Authors: Mukherjee Deepjyoti , Larsson Henrik , Odqvist Joakim
Published: September 2022

A recently developed phase-field model for simulating diffusion-induced grain boundary migration (DIGM) is applied to binary Fe–Zn. The driving force for the boundary migration is assumed to come from the coherency strain energy mechanism suggested by Sulonen. The effect of the angle of the grain boundary with the surface on the velocity of the boundary migration is studied in detail. The simulation results compare favorably with experimental observations, such as the oscillatory motion of the grain boundary, velocity of the moving grain boundary during DIGM, and the maximum value of mole fraction of Zn at the surface after 20 h of heat treatment.
In Situ Alloying of Fe-Cr-Co Permanent Magnet by Selective Laser Melting of Elemental Iron, Chromium and Cobalt Mixed Powders
Authors: He Yazhou , Zhang Hao , Su Hang , Shen Peng , Hou Yaqing , Zhou Dong
Published: September 2022

Fe-25Cr-15Co (wt.%) permanent magnets were fabricated via selective laser melting (SLM) and in situ alloying from a blend of Fe, Cr and Co elemental powders. Under the optimal laser scanning process, the as-built Fe-25Cr-15Co alloy has a homogeneous composition distribution without defects such as holes or un-melted particles, and presents a single α phase with the bcc crystal structure. The density of as-built samples was 7.705 g/cm3 (the relative density is 99.32%). The preferred magnetic properties of the sample in the isotropic state were obtained as Hc = 22.84 kA/m, Br = 0.86 T and (BH)max = 7.98 kJ/m3. The hardness and yield strength of Fe-25Cr-15Co permanent magnets are above 331.5 HV and 800 MPa, respectively. The results of this study verified the feasibility of fabricating Fe-Cr-Co permanent magnets by SLM in situ alloying and can be extended to a wide range of applications that require complex shapes with variable magnetic circuit characteristics or gradient structures.
Study of the Microstructure, Corrosion and Optical Properties of Anodized Aluminum for Solar Heating Applications
Authors: AlShamaileh Ehab , Altwaiq Abdelmnim M. , Esaifan Muayad , Al-Fayyad Heba , Shraideh Ziad , Moosa Iessa Sabbe , Hamadneh Imad
Published: September 2022

Humans are increasingly required to harvest green solar energy in order to reduce energy bills and save the environment from the excessive use of fossil resources. In this article, the microstructures of both commercial non-colored anodized Al and commercial blackened anodized Al were studied using optical and scanning electron microscopy in order to interpret the results of their use as solar absorbing surfaces. Microscopic examination showed that the thickness of the anodization layers of the non-colored anodized Al and the blackened anodized Al were approximately 11 µm and 14 µm, respectively, and they were perfectly adhered to the mother Al. The corrosion rate of all studied Al surfaces was investigated using the potentiodynamic polarization technique in 3.5% NaCl as the corrosive medium. The blackened anodized Al surface exhibited the highest corrosion resistance, which made it the best surface for solar heating systems. Moreover, raw Al, matte black painted Al, and blackened anodized Al were tested as selective surfaces for solar radiation in different weather conditions. Our results demonstrated the superiority of the blackened anodized Al in terms of the ability to absorb solar radiation, in addition to its higher corrosion resistance properties. In experimental testing, temperature values higher than 90 °C were reached several times. A gain of an extra 5 °C was achieved when using a double-glazed cover in comparison with a single-glazed setup. In conclusion, we highly recommend using a commercial blackened anodized Al surface to manufacture solar absorbing heaters, owing to its similarity in solar radiation absorptivity with the commercial matte black painted Al, excellent corrosion resistance, superior endurance upon long-term exposure to solar radiation, light weight, low price, and availability. Additionally, the light reflectance % test demonstrated the characteristics of the used solar selective surfaces.
Manipulating Nucleation Potency of Substrates by Interfacial Segregation: An Overview
Authors: Wang Yun , Wang Shihao , Que Zhongping , Fang Changming , Hashimoto Teruo , Zhou Xiaorong , Ramasse Quentin M. , Fan Zhongyun
Published: September 2022

During solidification of metallic materials, heterogeneous nucleation occurs on substrates, either endogenous or exogenous. The potency of the substrates for nucleation is mainly dependent upon the atomic arrangements on the substrate surface, which are affected by the lattice misfit between the substrate and the nucleated solid, the surface roughness at atomic scale, and the chemical interaction between the substrates and the melt. Extensive examinations on metal/substrate (M/S) interfaces at atomic scale by the state-of-the-art aberration (Cs) corrected STEM and associated EDS and EELS have shown that alloying elements in liquid melts tend to segregate at the interfaces, leading to the formation of various 2-dimensional compounds (2DCs) or 2-dimensional solutions (2DSs), depending upon segregation behavior of the elements. For instance, Al3Ti 2DC and Ti2Zr 2DC at the Al/TiB2 interface, Y2O3 2DC at the Mg/MgO interface, and a Si-rich 2DS layer at Al-Si/TiB2 interface have been identified. Such interfacial segregations significantly affect nucleation potency of the substrates, resulting in either promoting or impeding the heterogeneous nucleation process during solidification. In this paper, we present an overview of the current studies of interfacial segregation behavior, the structure and chemistry of interfaces, and their impacts on the subsequent heterogeneous nucleation and grain initiation processes. Our focus is on the advances made in the understanding of the mechanisms for nucleation and grain refinement. It is demonstrated that it is feasible to manipulate heterogeneous nucleation by modifying nucleation potency of a substrate through deliberate interfacial segregation of desirable elements, achieving effective control of the grain structure of cast metallic materials.
Microstructure and Mechanical Properties of Laser-Welded Joint of Tantalum and Stainless Steel
Authors: Feng Shanshan , Zhou Yongqiang , Zhu Zhengqiang , Chen Yanfei , Zhu Yunming
Published: September 2022

Bimetallic components welded by Ta and stainless steel have great promise for engineering applications, but there is relatively little relevant research. In this study, 0.6 mm-thick Ta and 304L stainless steel plates were laser welded, and the forming characteristics, microstructure, and mechanical properties of the welded joints were analyzed. First-principles calculations were also performed to explore the structural stabilization mechanisms of the two intermetallic compounds, TaFe2 and TaCr2, in terms of mechanical properties as well as electronic structure. The results showed that the weld surface was smooth and free from any defects. Fe-based solid solutions formed grains, while TaFe2, TaCr2, and some Fe-based solid solutions formed intergranular and eutectic structures. In addition, due to the presence of the brittle phases of TaFe2 and TaFe, the microhardness of the weld area can reach 650HV, with an average hardness of 530HV, which is much higher than that of the base material. The tensile shear of the joint at room temperature was 154.77 N/mm, and the fracture occurred in the weld zone on the steel side, showing brittle fracture. TaFe2 is a brittle intermetallic compound, while TaCr2 is ductile. Both TaFe2 and TaCr2 systems have dual properties of metallic and covalent bonding within them, and metallic bonding dominates.
Failure Analysis of Hydraulic Expanding Assembled Camshafts Using BP Neural Network and Failure Tree Theory
Authors: Ma Jianping , Yang Lianfa , Song Lin , Gao Zhiwei , Pang Saisai , Han Haimei
Published: September 2022

Due to the complex and changeable working environment of assembled camshafts using tube hydroforming (THF) technology, the manifestations of failure, the causes of failure and the preventive measures for these failures are a major concern. Therefore, in view of this new connection technology for assembled camshafts, it is important to put forward a prediction and evaluation method of failure for hydraulic expanding assembled camshafts. In this study, an isometric-trilateral profile cam was used to complete the hydroforming connection with the hollow shaft (tube) under different hydraulic pressures. Orthogonal torsion experiment and laser measurement experiment were performed. Finite element analysis was carried out using ABAQUS 6.14 software, and relevant research data were obtained. A more accurate BP neural network model was constructed to predict the main failure factors of assembled camshafts. The failure manifestations of assembled camshafts are displayed by the experiment from the microscopic perspective. The causes of failure are analyzed by using the minimum cut set in the failure Tree (FT) theory. The effect of basic causes on the subsystems is analyzed, and the weight distribution of the main events in the FT is given. Finally, the specific measures to prevent failure are proposed from a macro perspective. The research is of great significance to study the failures of assembled camshafts in service to further the production, manufacturing, failure prevention, faults monitoring and performance improvement of assembled camshafts in the engine industry.
Associated Effect of SLC40A1 and TMPRSS6 Polymorphisms on Iron Overload
Authors: Duca Lorena , Granata Francesca , Di Pierro Elena , Brancaleoni Valentina , Graziadei Giovanna , Nava Isabella
Published: September 2022

Mutations in the ferroportin (FPN) gene SLC40A1 alter iron recycling and cause disturbances in iron homeostasis. The variants of TMPRSS6 contribute to the development of iron deficiencies. In this study, we determined the role of FPN and TMPRSS6 gene polymorphisms in the modulation of iron homeostasis based on biochemical parameters. PCR analysis and sequencing were performed to determine the single nucleotide polymorphisms (SNPs) SLC40A1 c.44–24G>C (rs1439816), SLC40A1 c.663T>C (rs2304704), and TMPRSS6 c.2207T>C (rs855791). Hemoglobin concentration and iron status were determined by standard procedures. We studied 79 iron-loaded individuals for SLC40A1 polymorphisms. Interestingly, 35/79 individuals with SLC40A1 SNPs also carried a TMPRSS6 c.2207T>C polymorphism. The biochemical values of the iron overloaded individuals were compared to those of the individuals carrying TMPRSS6 SNPs and the healthy individuals (wild-type group). The ferritin concentration, transferrin saturation % (TS%), and hemoglobin concentration were significantly higher in the participants with FPN SNPs than in the other three groups. The ferritin concentration and TS% were higher in participants with both SLC40A1 and TMPRSS6 SNPs than in the TMPRSS6 and wild-type groups, while hemoglobin concentration was significantly higher than that in the TMPRSS6 SNP group only. The participants with TMPRSS6 SNPs had significantly lower ferritin concentration, TS%, and hemoglobin concentration than all the other groups. SLC40A1 and TMPRSS6 SNPs might act in the opposite direction, preventing the development of severe iron overload, and the modulation of the iron status by TMPRSS6 SNPs might provide protection.
Revisiting Quantification of Phenylalanine/Tyrosine Flux in the Ochronotic Pathway during Long-Term Nitisinone Treatment of Alkaptonuria
Authors: Ranganath Lakshminarayan R. , Hughes Andrew T. , Davison Andrew S. , Khedr Milad , Imrich Richard , Rudebeck Mattias , Olsson Birgitta , Norman Brendan P. , Bou-Gharios George , Gallagher James A. , Milan Anna M.
Published: September 2022

Changes in the phenylalanine (PHE)/tyrosine (TYR) pathway metabolites before and during homogentisic acid (HGA)-lowering by nitisinone in the Suitability of Nitisinone in Alkaptonuria (AKU) 2 (SONIA 2) study enabled the magnitude of the flux in the pathway to be examined. SONIA 2 was a 48-month randomised, open-label, evaluator-blinded, parallel-group study performed in the UK, France and Slovakia recruiting patients with confirmed AKU to receive either 10 mg nitisinone or no treatment. Site visits were performed at 3 months and yearly thereafter. Results from history, photographs of eyes/ears, whole body scintigraphy, echocardiography and abdomen/pelvis ultrasonography were combined to produce the Alkaptonuria Severity Score Index (cAKUSSI). PHE, TYR, hydroxyphenylpyruvate (HPPA), hydroxyphenyllactate (HPLA) and HGA metabolites were analysed by liquid chromatography/tandem mass spectrometry in 24 h urine and serum samples collected before and during nitisinone. Serum metabolites were corrected for total body water (TBW), and the sum of 24 h urine plus total body water metabolites of PHE, TYR, HPPA, HPLA and HGA were determined. The sum of urine metabolites (PHE, TYR, HPPA, HPLA and HGA) were similar pre- and peri-nitisinone. The sum of TBW metabolites and sum TBW + URINE metabolites were significantly higher peri-nitisinone (p < 0.001 for both) compared with pre-nitisinone baseline. Significantly higher concentrations of metabolites from the tyrosine metabolic pathway were observed during treatment with nitisinone. Arguments for unmasking of the ochronotic pathway and biliary elimination of HGA are put forward.
Betatrophin and Insulin Resistance
Authors: Guo Qi , Cao Shicheng , Wang Xiaohong
Published: September 2022

Betatrophin (angiopoietin-like protein 8 (ANGPTL8)) is a hormone that was recently discovered in the human liver. Multiple homologous sequences have been detected in mammalian liver, white adipose, and brown adipose tissues. Betatrophin is crucial for the development of type 2 diabetes (T2D), insulin resistance, and lipid metabolism. Similar to the intake of insulin, thyroid hormones, irisin, and calories, betatrophin expression in the organism is usually attributed to energy consumption or heat generation. It can mediate the activity of lipoprotein lipase (LPL), which is the key enzyme of lipoprotein lipolysis. Due to its association with metabolic markers and the roles of glucose and lipid, the physiological function of betatrophin in glucose homeostasis and lipid metabolism can be more comprehensively understood. Betatrophin was also shown to facilitate pancreatic β-cell proliferation in a mouse model of insulin resistance. There are also reports that demonstrate that betatrophin regulates triglycerides (TGs) in the liver. Therefore, the process of regulating the physiological function by betatrophin is complicated, and its exact biological significance remains elusive. This study provides a comprehensive review of the current research, and it discusses the possible physiological functions of betatrophin, and specifically the mechanism of betatrophin in regulating blood glucose and blood lipids.
Preparation of Cemented Carbide Insert Cutting Edge by Flexible Fiber-Assisted Shear Thickening Polishing Method
Authors: Shao Lanying , Zhou Yu , Fang Wei , Wang Jiahuan , Wang Xu , Deng Qianfa , Lyu Binghai
Published: September 2022

Reasonable cutting edge preparation can eliminate microscopic defects and improve the performance of a cutting tool. The flexible fiber-assisted shear thickening polishing method was used for the preparation of cemented carbide insert cutting edge. The influences of the polishing angle and polishing speed on the cutting edge preparation process were investigated, and the cutting edge radius and K-factor were employed as evaluation indexes to evaluate the edge shape. A prediction model of the cutting edge radius was also established using the mathematical regression method. The results show that the polishing angle has a more significant effect on the cutting edge radius. The cutting edge preparation efficiency is the highest under the polishing angle of 10°, and the cutting edge radius increased from the 15 ± 2 μm to 110 ± 5 μm in 5 min. The cutting edge shape can be controlled by adjusting the polishing angle, and the K-factor varies from 0.14 ± 0.03 to 0.56 ± 0.05 under the polishing angle (from −20° to 20°). The polishing speed has a less effect on the cutting edge radius and shape, but increasing the polishing speed within a certain range can improve the efficiency of cutting edge preparation. The flank face roughness decreased from the initial Ra 163.1 ± 10 nm to Ra 5.2 ± 2 nm at the polishing angle of −20°, which is the best polishing angle for the flank face surface roughness. The ANOVA method was employed to evaluate the effective weight of the polishing angle and polishing speed on preparation efficiency. The polishing angle (86.79%) has the more significant influence than polishing speed (13.21%) on the cutting edge preparation efficiency. The mathematical regression method was used to establish the model of the prediction of the cutting edge radius with polishing angle and speed, and the models were proved rationally. The results indicate that the FF-STP is an effective method for the high consistency preparation of cemented carbide insert cutting edge.
Performance Improvement of Glass Microfiber Based Thermal Transpiration Pump Using TPMS
Authors: Parittothok Pitipat , Poolwech Chanon , Tanteng Tanawit , Wongwiwat Jakrapop
Published: September 2022

The Knudsen pump, known as a thermal transpiration membrane, is an air inducer that has been mostly studied for small-scale power generation devices. It is a porous medium that does not require any mechanically moving component, but rather uses the temperature gradient across two surfaces of the membrane to induce air from the colder side to the hotter side. If the temperature on the colder side of the membrane is reduced by a thermal guard, the pumping performance of the membrane seems to be improved. Therefore, the membrane integrating with TPMS structures as thermal guards for both experiment and simulation were conducted in this study. The results of flow rate and temperature distribution on the membrane surface were compared. Three characteristic parameters of the membrane, i.e., area factor, pore radius and permeability, were found and can be used in an equation to estimate the air flow rate through the membrane. Diamond was found to be the highest flow improvement while Primitive was the lowest flow improvement. The simulation results with varying %RD also supported that the contact area between the TPMS structure and the membrane inlet surface made Diamond conduct more heat out from the membrane surface than other TPMS structures.