bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation on the Cutting of Additively Manufactured Ti6Al4V with Wire-EDM and the Analytical Modelling of Cutting Speed and Surface Roughness
Authors: Galati Manuela , Antonioni Paolo , Calignano Flaviana , Atzeni Eleonora
Published: March 2023

Additive manufacturing (AM) technologies for metallic materials allow for the manufacturing of high-performance components optimised in weight, geometry, and mechanical properties. However, several post-processing operations are needed after production, including removing parts from the build platform. This operation is essential and must be performed rapidly, precisely, and with a good surface finishing. This work presents an experimental investigation of the wire electric discharge machining (W-EDM) process of Ti6Al4V specimens produced by AM technologies. The influence of cutting parameters is analysed compared to the material produced by conventional technology. Models of cutting speed and surface roughness obtained by a W-EDM are inferred from the collected data. Remarkably, the results show that the manufacturing process used to produce the components plays a crucial role in defining the final surface roughness and the most significant parameters affecting the machining performance.
Improving the Classification of PCNSL and Brain Metastases by Developing a Machine Learning Model Based on 18F-FDG PET
Authors: Cui Can , Yao Xiaochen , Xu Lei , Chao Yuelin , Hu Yao , Zhao Shuang , Hu Yuxiao , Zhang Jia
Published: March 2023

Background: The characteristic magnetic resonance imaging (MRI) and the positron emission tomography (PET) findings of PCNSL often overlap with other intracranial tumors, making definitive diagnosis challenging. PCNSL typically shows iso-hypointense to grey matter on T2-weighted imaging. However, a particular part of PCNSL can demonstrate T2-weighted hyperintensity as other intracranial tumors. Moreover, normal high uptake of FDG in the basal ganglia, thalamus, and grey matter can mask underlying PCNSL in 18F-FDG PET. In order to promote the efficiency of diagnosis, the MRI-based or PET/CT-based radiomics models combining histograms with texture features in diagnosing glioma and brain metastases have been widely established. However, the diagnosing model for PCNSL has not been widely reported. The study was designed to investigate a machine-learning (ML) model based on multiple parameters of 2-deoxy-2-[18F]-floor-D-glucose (18F-FDG) PET for differential diagnosis of PCNSL and metastases in the brain. Methods: Patients who underwent an 18F-FDG PET scan with untreated PCNSL or metastases in the brain were included between May 2016 and May 2022. A total of 126 lesions from 51 patients (43 patients with untreated brain metastases and eight patients with untreated PCNSL), including 14 lesions of PCNSL, and 112 metastatic lesions in the brain, met the inclusion criteria. PCNSL or brain metastasis was confirmed after pathology or clinical history. Principal component analysis (PCA) was used to decompose the datasets. Logistic regression (LR), support vector machine (SVM), and random forest classification (RFC) models were trained by two different groups of datasets, the group of multi-class features and the group of density features, respectively. The model with the highest mean precision score was selected. The testing sets and original data were used to examine the efficacy of models separately by using the weighted average F1 score and area under the curve (AUC) of the receiver operating characteristic curve (ROC). Results: The multi-class features-based RFC and SVM models reached identical weighted-average F1 scores in the testing set, and the score was 0.98. The AUCs of RFC and SVM models calculated from the testing set were 1.00 equally. Evaluated by the original dataset, the RFC model based on multi-class features performs better than the SVM model, whose weighted-average F1 scores of the RFC model calculated from the original data were 0.85 with an AUC of 0.93. Conclusions: The ML based on multi-class features of 18F-FDG PET exhibited the potential to distinguish PCNSL from brain metastases. The RFC models based on multi-class features provided comparatively high efficiency in our study.
Risk Assessment of Earthquake–Landslide Hazard Chain Based on CF-SVM and Newmark Model—Using Changbai Mountain as an Example
Authors: Ke Kai , Zhang Yichen , Zhang Jiquan , Chen Yanan , Wu Chenyang , Nie Zuoquan , Wu Junnan
Published: March 2023

Changbai Mountain is an important part of the development and opening pilot area of Changjitu. It is the birthplace of Songhua River, Yalu River, and Tumen River, and is known as the source of the three rivers. Millions of people live in the basin. A volcanic eruption accompanied by earthquakes would lead to a large number of landslides, debris flows, and show a chain effect, the formation of a secondary geological disaster chain, which is a serious threat to people’s lives and property safety. This paper selected indexes from three aspects: the hazard of earthquake-induced geological disaster chain, the exposure and vulnerability of disaster-bearing bodies, and the risk assessment of earthquake-induced geological disaster chain. The sensitivity values of each influence factor were calculated by the certainty factor (CF) using the support vector machine, and then, the susceptibility assessment was obtained. The cumulative displacement calculated by the Newmark model represented the potential risk intensity. We considered the Changbai Mountain volcanic earthquake–landslide disaster chain as an example. The results of risk assessment showed that the extremely high and high risk areas were mainly located within the 12 km radius of Tianchi Lake, and the other areas in the study area were mainly associated with very low to low risk values. The verification results showed that the receiver operating characteristic (ROC) curve area was 0.8373, indicating that the method was very effective in the identification and assessment of seismic hazard chain risk. In these high-risk areas, relevant countermeasures should be formulated to prevent the risk of geological disasters, strengthen the implementation of regional disaster prevention and reduction work, and ensure the safety of residents’ lives and property.
Synergistic Effect of Multiple Metals Present at Slightly Lower Concentration than the Australian Investigation Level Can Induce Phytotoxicity
Authors: Khan Naser , Bolan Nanthi , Clark Ian , Meier Sebastian , Lewis David , Sánchez-Monedero Miguel A.
Published: March 2023

An individual trace metal present in a soil at its ecological screening value or investigation level (trigger/threshold) is expected to cause phytotoxicity. However, phytotoxicity may be induced by a mixture of multiple metals, each present at a concentration lower than the corresponding investigation level. To investigate the accumulative impact of metals present below their individual investigation levels, three successive phytotoxicity trials were conducted in a greenhouse using the triticale plant CrackerJack (Triticosecale rimpaui), a cereal crop, in a sandy acidic soil treated jointly with Cd, Cu, and Zn at various rates. Seed germination and seedling growth were monitored. The metal rates in the first two trials were either too toxic or nontoxic. In the third trial, it was found that the mixture of Cd, Cu, and Zn at rates of 2.5, 97.5, and 188 mg kg−1, respectively, did not affect seed germination, but caused a slight reduction in plant growth. Although metal concentrations used were lower than the Australian Ecological Investigation Level (Urban) for Cd, Cu, and Zn, which are 3.0, 100, and 200 mg kg−1, respectively, the reduction occurred due to synergy. It was concluded that, to enhance the usefulness of environmental investigation limits, the synergistic effects of multiple metals present at levels slightly below the established limits must be considered.
Sweet Syndrome Associated with Myelodysplastic Syndrome—A Review of a Multidisciplinary Approach
Authors: Ferea Cătălina Roxana , Mihai Stejara Nicoleta , Balan Gabriela , Badescu Minerva Codruta , Tutunaru Dana , Tatu Alin Laurențiu
Published: March 2023

Sweet syndrome (SS) is a rare disease described as a febrile neutrophilic dermatosis with acute onset, the pathogenesis of which has not yet been elucidated. The syndrome is characterized by the sudden onset of erythematous infiltrated papules or plaques located on the upper body and is associated with fever, leukocytosis and neutrophilia. The lesions show a dense dermal infiltration with mature neutrophils. The condition is responsive to systemic steroids. The central nervous system, bones, muscles, eyes, ears, mouth, heart, lung, liver, kidneys, intestines, and spleen may be affected by SS as extracutaneous manifestations. More and more cases have been found to be associated with malignancies, particularly myelodysplastic syndrome, and, less frequently, other hematologic malignancies or solid tumors. Approximately 21% of patients with SS have an associated malignancy and up to 80% of MASS cases are associated with hematological diseases, predominantly myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Myelodysplastic syndrome is a clonal disease of the bone marrow characterized by inefficient hematopoiesis, dysplasia of the bone marrow and peripheral cytopenias. Affected patients have a high risk of leukemic transformation. After analyzing later studies and current practical aspects regarding MDS-related SS, we suggest an algorithm for evaluating these patients.
Brolucizumab in Pretreated Neovascular Age-Related Macular Degeneration: Case Series, Systematic Review, and Meta-Analysis
Authors: Hänsli Christof , Schild Christin , Pfister Isabel , Garweg Justus G.
Published: March 2023

Background: Recalcitrant neovascular age-related macular degeneration (rnAMD) despite intensive intravitreal anti-neovascular endothelial growth factor (VEGF) treatment, can be handled by switching to another anti-VEGF agent. This first systematic review and meta-analysis presents long-term data after switching from another anti-VEGF agent to brolucizumab. Methods: Retrospective case series over two years of patients switched to brolucizumab, and a systematic review and meta-analysis of peer-reviewed studies presenting patients switched to brolucizumab. Weighted mean differences based on the random-effects models were calculated for best-corrected visual acuity (BCVA) and central subfield thickness (CST). Results: The systematic review draws on 1200 eyes switched to brolucizumab. The meta-analysis showed a clinically irrelevant decrease in BCVA after one and two months, together with significant decreases in CST for up to one year after the switch but lacking power over 2 years. Of twelve eyes (twelve patients) in our case series, five continued treatment for two years without experiencing significant changes. Conclusions: After switch to brolucizumab, a significant morphological improvement with CST reduction was shown in eyes with rnAMD. The small worsening of BCVA may be owing to the chronically active nature of rnAMD. Brolucizumab thus remains a treatment option in rnAMD despite its potential side effects.
Cyanobacteria and Algal-Based Biological Life Support System (BLSS) and Planetary Surface Atmospheric Revitalizing Bioreactor Brief Concept Review
Authors: Keller Ryan , Goli Karthik , Porter William , Alrabaa Aly , Jones Jeffrey A.
Published: March 2023

Exploring austere environments required a reimagining of resource acquisition and utilization. Cyanobacterial in situ resources utilization (ISRU) and biological life support system (BLSS) bioreactors have been proposed to allow crewed space missions to extend beyond the temporal boundaries that current vehicle mass capacities allow. Many cyanobacteria and other microscopic organisms evolved during a period of Earth’s history that was marked by very harsh conditions, requiring robust biochemical systems to ensure survival. Some species work wonderfully in a bioweathering capacity (siderophilic), and others are widely used for their nutritional power (non-siderophilic). Playing to each of their strengths and having them grow and feed off of each other is the basis for the proposed idea for a series of three bioreactors, starting from regolith processing and proceeding to nutritional products, gaseous liberation, and biofuel production. In this paper, we discuss what that three reactor system will look like, with the main emphasis on the nutritional stage.
Hot Deformation Behaviour of Additively Manufactured 18Ni-300 Maraging Steel
Authors: Tomiczek Błażej , Snopiński Przemysław , Borek Wojciech , Król Mariusz , Gutiérrez Ana Romero , Matula Grzegorz
Published: March 2023

In this article, hot compression tests on the additively produced 18Ni-300 maraging steel 18Ni-300 were carried out on the Gleeble thermomechanical simulator in a wide temperature range (900–1200 °C) and at strain rates of 0.001 10 s−1. The samples were microstructurally analysed by light microscopy and scanning electron microscopy with electron backscatter diffraction (EBSD). This showed that dynamic recrystallization (DRX) was predominant in the samples tested at high strain rates and high deformation temperatures. In contrast, dynamic recovery (DRV) dominated at lower deformation temperatures and strain rates. Subsequently, the material constants were evaluated in a constitutive relationship using the experimental flow stress data. The results confirmed that the specimens are well hot workable and, compared with the literature data, have similar activation energy for hot working as the conventionally fabricated specimens. The findings presented in this research article can be used to develop novel hybrid postprocessing technologies that enable single-stage net shape forging/forming of AM maraging steel parts at reduced forming forces and with improved density and mechanical properties.
Effective Boundary Conditions and Stochastic Crack Distribution for Modelling Guided Waves Scattering by a Partially Closed Interfacial Delamination in a Laminate
Authors: Golub Mikhail V. , Doroshenko Olga V. , Gu Yan
Published: March 2023

Cohesive and adhesive bindings degrade during operation and maintenance even if contacting materials in a manufactured laminated structure are perfectly matched at the interfaces. Two modelling approaches for describing partially closed delaminations or imperfect contact zones, which often occurs at the interfaces, are examined and considered. To confirm the adequateness of the applicability of the effective spring boundary conditions for guided wave scattering by a finite length delamination, guided wave propagation through a damaged zone with a distribution of micro-cracks is compared with an equivalent cohesive zone model, where the spring stiffnesses for the effective boundary conditions are calculated using the properties of the considered crack distribution. Two kinds of local interfacial decohesion zones with an imperfect contact at the interfaces are considered: uniform partially closed delaminations and bridged cracks. The possibility of the employment of the effective spring boundary conditions to substitute a distribution of micro-cracks is analysed and discussed. Two algorithms of generation of a distribution of open micro-cracks providing characteristics equivalent to the effective boundary conditions are presented and examined. The influence of the characteristics of a delamination on wave characteristics (eigenfrequencies, eigenforms, transmission coefficient) is investigated for several kinds of partially closed delaminations.
Performance Evaluation of Input Power of Diode Laser on Machined Leather Specimen in Laser Beam Cutting Process
Authors: Khalaf Tamer , Thangaraj Muthuramalingam , Moiduddin Khaja , Swaminathan Vasanth , Mian Syed Hammad , Ahmed Faraz , Aboudaif Mohamed Kamaleldin
Published: March 2023

Numerous industries, including footwear, handicrafts, and the automobile industry, utilize leather materials. The main goal of this study was to investigate the effect of input power of the diode laser in laser cutting on vegetable chrome tanned buffalo leather to enhance the cutting process. In the present investigation, carbonization, kerf width, and material removal rate (MRR) were taken as performance measures. The diode-based laser beam machining was designed and fabricated with 2.5 W, 5.5 W, and 20 W diode laser to cut vegetable chrome tanned leather. The high-intensity 20 W diode laser produced lower carbonization, lower kerf width, and higher material removal rate compared with the 2.5 W and 5.5 W diodes. This improved performance was due to the adjustable features associated with this diode laser actuation in the form of circular shape with adjustable diameter. A high power with a lower spot size under pulsed mode can produce higher power density. Since a higher power density can establish less interaction time, it produces lower carbonization. Due to the ability of the 20 W diode laser driver to control the beam shape and size, it could produce a lower kerf width and higher MRR. The optimal parameters for cutting chrome vegetable tanned cow leather were a standoff distance of 18 mm, feed rate of 200 mm/min, and duty cycle of 70%.
Review of Play and Preisach Models for Hysteresis in Magnetic Materials
Authors: Mörée Gustav , Leijon Mats
Published: March 2023

This paper studies the properties of the Preisach model and the play model, and compare their similarities. Both are history-dependent hysteresis models that are used to model magnetic hysteresis. They are described as discrete sums of simple hysteresis operators but can easily be reformulated as integral equations of continuous distribution functions using either a Preisach weight distribution function or a play distribution function. The models are mostly seen as phenomenological or mathematical tools but can also be related to friction-like pinning of domain-wall motions, where Rayleigh’s law of magnetic hysteresis can be seen as the simplest case on either the play model or the Preisach model. They are poor at modeling other domain behavior, such as nucleation-driven hysteresis. Yet another hysteresis model is the stop model, which can be seen as the inverted version of the play model. This type of model has advantages for expressions linked to energy and can be related to Steinmetz equation of hysteresis losses. The models share several mathematical properties, such as the congruency property and wiping-out property, and both models have a history of dependence that can be described by the series of past reversal points. More generally, it is shown that the many models can be expressed as Preisach models, showing that they can be treated as subcategories of the Preisach type models. These include the play model, the stop model and also the alternative KP-hysteron model.
Numerical Analysis on Dynamic Response of CFRP-Wrapped RC Columns under Lateral Impact Loading
Authors: Liu Tao , Xu Xiaoqing , Chen Lin , Kim Sanghee , Hong Seongwon
Published: March 2023

This paper presents a numerical study examining the dynamic response and resistance mechanism of reinforced concrete (RC) columns strengthened with or without carbon-fiber-reinforced polymer (CFRP) wraps under lateral impact loading by using the software LS-DYNA. First, the information of eight column models was briefly introduced as part of the laboratory experimental program from the literature. Secondly, finite element (FE) models were established in terms of the geometries of impact tests. Then, a detailed comparison between numerical results and experimental results was made, and FE models showed a relatively high simulation accuracy. Subsequently, a series of parametric analyses were carried out with a focus on the effects of axial compression ratio, the boundary condition at the column top, the layer number of CFRP wraps, and the impact velocity and impact height on the dynamic responses of plain and strengthened columns. The results demonstrated that the CFRP retrofit mechanism was not activated during the initial Stage-I when the impact force rapidly increased to the first peak and then decreased to zero. CFRP strengthening came into play in the second stage, Stage-II, and affected the response of the shear force and moment along the column height, as well as had a great influence on the control of shear damage. The dynamic response of RC columns was more sensitive to the impact velocity than to other parameters, regardless of whether CFRP wrapping was applied. The axial compression ratio would have a different influence on the column failure mode if the impact velocity was varied. The variation in impact height and boundary condition at the column top had little influence on the damage mode of strengthened columns.
Experimental Research for the Establishment of the Optimal Forging and Heat Treatment Technical Parameters for Special Purpose Forged Semi-Finishes
Authors: Constantin Nicolae , Ioana Adrian , Caloian Valentina , Rucai Valeriu , Dobrescu Cristian , Istrate Alexandra , Pasare Vili
Published: March 2023

The authors present in this paper the experimental results and conclusions obtained after conducting a comparative study on three samples of forged semi-finished products from the steel brands 10CrMo9-10, 25CrMo4, and 42CrMo4. These are common heat-resistant alloy steels used in various industries nationally and internationally. This study aimed to test under the same identical experimental conditions of forging and heat treatment of three samples made of three different brands of steels 10CrMo9-10, 25CrMo4, and 42CrMo4. Analyzing the experimental results obtained, it can be seen for which of the three brands of tested steels the best forging and heat treatment parameters are obtained. Following experimental research, the best material was determined by analyzing the results obtained for the mechanical characteristics (tensile tests according to DNVGL-RP0034-SFC2 and NACE MR0175–hardness 207-235 HBW) and austenitic grain size. The authors determined that among the three types of steels analyzed, 10CrMo9-10 best meets the imposed requirements. This statement is in view of the comparative analysis of the results of experimental research.
Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates
Authors: Suescum-Morales David , Fernández-Ledesma Enrique , González-Caro Ágata , Merino-Lechuga Antonio Manuel , Fernández-Rodríguez José María , Jiménez José Ramón
Published: March 2023

The objective of the present study was to explore three types of vibro-compacted precast concrete mixtures replacing fine and coarse gravel with a recycled/mixed concrete aggregate (RCA or MCA). The portlandite phase found in RCA and MCA by XRD is a “potential” CO2 sink. CO2 curing improved the compressive strength in all the mixtures studied. One tonne of the mixtures studied could be decarbonised after only 7 days of curing 13,604, 36,077 and 24,635 m3 of air using natural aggregates, RCA or MCA, respectively. The compressive strength obtained, XRD, TGA/DTA and carbon emission evaluation showed that curing longer than 7 days in CO2 was pointless. The total CO2 emissions by a mixture using CO2 curing at 7 days were 221.26, 204.38 and 210.05 kg CO2 eq/m3 air using natural aggregates, RCA or MCA, respectively. The findings of this study provide a valuable contribution to carbon emission evaluation of CO2 curing in vibro-compacted precast concrete with recycled/mixed concrete aggregates (RCA or MCA). The technology proposed in this research facilitates carbon capture and use and guarantees enhanced compressive strength of the concrete samples.
Morphology Determines an Efficient Coherent Electron Transport for Push–Pull Organic Semiconductors Based on Triphenylamine and Dicyanovinyl Groups
Authors: Romero Alexander , Velasco-Medina Jaime , Ortiz Alejandro
Published: March 2023

The morphology of the active layer in organic solar cells is fundamental for achieving high power conversion efficiency. However, the morphological characteristics for optimal performance are still being investigated. An atomistic computational approach is required to determine the relationship between active layer morphology and performance. Since the organic solar cell has multiple phases and interfaces, the computational modeling of charge generation and transport is challenging. We then used a set of push–pull semiconductors to illustrate how the electronic transmission spectrum, derived from the Landauer–Büttiker formalism, can be used to investigate the efficiency of coherent charge transport across anisotropic organic solids. The electronic transmission spectrum was calculated from the electronic band structure obtained using the density-functional-based tight-binding method. We found that coherent charge transport was more efficient along the direction parallel with the interface between the electron-acceptor and electron-donor moieties for a herringbone morphology.
Effect of Low Nesquehonite Addition on the Hydration Product and Pore Structure of Reactive Magnesia Paste
Authors: Shi Run , Hao Yuehan , Chen Deping , Liu Wenxin
Published: March 2023

Reactive magnesia cement is considered an eco-efficient binder due to its low synthesis temperature and CO2 absorption properties. However, the hydration of pure MgO–H2O mixtures cannot produce strong Mg(OH)2 pastes. In this study, nesquehonite (Nes, MgCO3·3H2O) was added to the MgO–H2O system to improve its strength properties, and its hydration products and pore structure were analyzed. The experimental results showed that the hydration product changed from small plate-like Mg(OH)2 crystals to interlaced sheet-like crystals after the addition of a small amount of Nes. The porosity increased from 36.3% to 64.6%, and the total pore surface area increased from 4.6 to 118.5 m2/g. At the same time, most of the pores decreased in size from the micron scale to the nanometer scale, which indicated that Nes had a positive effect on improving the pore structure and enhancing the compressive strength. Combined with an X-ray diffractometer (XRD), a Fourier transform infrared spectrometer (FTIR), and a simultaneous thermal analyzer (TG/DSC), the hydration product of the sample after Nes addition could be described as xMgCO3·Mg(OH)2·yH2O. When Nes was added at 7.87 and 14.35 wt%, the x-values in the chemical formula of the hydration products were 0.025 and 0.048, respectively. These small x-values resulted in lattice and property parameters of the hydration products that were similar to those of Mg(OH)2.
Numerical and Experimental Investigations on Residual Stress and Hardness within a Cold Forward Extruded Preform
Authors: Ku Tae-Wan
Published: March 2023

Using a preform fabricated by a cold forward extrusion process, the present study numerically predicted and experimentally investigated its residual stress and microstructural characteristics, as well as its plastic deformation damage and hardness. Prior to realizing the preform, AISI 1035 cold-drawn medium carbon steel material with a diameter of 50.0 mm and a height of 121.0 mm is first spheroidized and annealed, after which phosphophyllite is used to coat its outer surface. To identify the influence of the spheroidizing and annealing on the mechanical properties and the microstructural phase, uniaxial compression tests and microscopic observations are carried out. After assuming the deformation behavior of the workpiece during the cold forward extrusion with a plastic material model and with an elasto-plastic material model, separately, three-dimensional finite element simulations are adopted to visualize the residual stress and the plastic deformation damage. The preform produced by cold forward extrusion is fully scanned by using an optical 3D scanner, the Vickers micro-hardness is measured, and the residual stress through EBSD (electron backscatter diffraction) analysis is observed. Briefly, the results show that the ferrite and pearlite within the raw workpiece is well spheroidized by the heat treatment, and that there is a decrease in the KAM (kernel average misorientation) value of about 40%. In terms of the preform obtained by the cold forward extrusion, the dimensional requirement is more suitably met with the predicted layout when adopting the elasto-plastic material model than that of the plastic material one, and the numerically predicted residual stress agrees with the Vickers micro-hardness distribution. It can be verified that the dislocation density (or the internally stored strain energy) based on the IQ map and the IPF map is substantially increased around the extrusion region, and that the KAM value is increased by roughly 516% as the whole average of the observed values.
Additive Manufacturing Technologies of High Entropy Alloys (HEA): Review and Prospects
Authors: Ron Tomer , Shirizly Amnon , Aghion Eli
Published: March 2023

Additive manufacturing (AM) technologies have gained considerable attention in recent years as an innovative method to produce high entropy alloy (HEA) components. The unique and excellent mechanical and environmental properties of HEAs can be used in various demanding applications, such as the aerospace and automotive industries. This review paper aims to inspect the status and prospects of research and development related to the production of HEAs by AM technologies. Several AM processes can be used to fabricate HEA components, mainly powder bed fusion (PBF), direct energy deposition (DED), material extrusion (ME), and binder jetting (BJ). PBF technologies, such as selective laser melting (SLM) and electron beam melting (EBM), have been widely used to produce HEA components with good dimensional accuracy and surface finish. DED techniques, such as blown powder deposition (BPD) and wire arc AM (WAAM), that have high deposition rates can be used to produce large, custom-made parts with relatively reduced surface finish quality. BJ and ME techniques can be used to produce green bodies that require subsequent sintering to obtain adequate density. The use of AM to produce HEA components provides the ability to make complex shapes and create composite materials with reinforced particles. However, the microstructure and mechanical properties of AM-produced HEAs can be significantly affected by the processing parameters and post-processing heat treatment, but overall, AM technology appears to be a promising approach for producing advanced HEA components with unique properties. This paper reviews the various technologies and associated aspects of AM for HEAs. The concluding remarks highlight the critical effect of the printing parameters in relation to the complex synthesis mechanism of HEA elements that is required to obtain adequate properties. In addition, the importance of using feedstock material in the form of mix elemental powder or wires rather than pre-alloyed substance is also emphasized in order that HEA components can be produced by AM processes at an affordable cost.
Evaluation of Equiatomic CrMnFeCoNiCu System and Subsequent Derivation of a Non-Equiatomic MnFeCoNiCu Alloy
Authors: Ter-Isahakyan Artashes , Balk Thomas John
Published: March 2023

Investigation into non-equiatomic high-entropy alloys has grown in recent years due to questions about the role of entropy stabilization in forming single-phase solid solutions. Non-equiatomic alloys have been shown to retain the outstanding mechanical properties exhibited by their equiatomic counterparts and even improve electrical, thermal, and magnetic properties, albeit with relaxed composition bounds. However, much remains to understand the processing–structure–property relationships in all classes of so-called high-entropy alloys (HEAs). Here, we are motivated by the natural phenomena of crystal growth and equilibrium conditions to introduce a method of HEA development where controlled processing conditions determine the most probable and stable composition. This is demonstrated by cooling an equiatomic CrMnFeCoNiCu alloy from the melt steadily over 3 days (cooling rate ~4 °C/h). The result is an alloy containing large Cr-rich precipitates and an almost Cr-free matrix exhibiting compositions within the MnFeCoNiCu system (with trace amounts of Cr). From this juncture, it is argued that the most stable composition is within the CrMnFeCoNiCu system rather than the CrMnFeCoNi system. With further optimization and evaluation, a unique non-equiatomic alloy, Mn17Fe21Co24Ni24Cu14, is derived. The alloy solidifies and recrystallizes into a single-phase face-centered cubic (FCC) polycrystal. In addition to possible applications where Invar is currently utilized, this alloy can be used in fundamental studies that contrast its behavior with its equiatomic counterpart and shed light on the development of HEAs.
Managing the Heat Release of Calcium Sulfoaluminate Cement by Modifying the Ye’elimite Content
Authors: Kleib Joelle , Aouad Georges , Benzerzour Mahfoud , Abriak Nor Edine , Zakhour Mirvat
Published: March 2023

Nowadays, calcium sulfoaluminate cement (CSA) is garnering a large amount of attention worldwide and is being promoted as a sustainable alternative to Portland cement for specific applications. This study aimed to control the heat release of CSA cement paste by choosing the appropriate composition. For this purpose, different calcium sulfoaluminate clinkers with up to 75 wt. % of ye’elimite were synthetized. Then, a reactivity study on the synthesized clinkers was conducted while varying the amount of gypsum added. The heat of hydration was measured by isothermal calorimetry. The influence of the ye’elimite content on the heat release and on the compressive strength was investigated. According to the findings, the amount of ye’elimite in the cement has a direct relationship with the heat release. The heat release as well as the mechanical performance increase with the increase in the ye’elimite content in the CSA cement. An equation allowing the prediction of the total heat release after 24 h is provided. Such data can be of particular interest to consultants aiming at the reduction of thermal cracking in massive concrete.
Fatty Acids in Waste Tissues: The Nutraceutical Value of Gonads and Livers from the Moroccan Hypophthalmichthys molitrix and Cyprinus carpio Fishes
Authors: Tommonaro Giuseppina , Paris Debora , Guerriero Giulia , Majdoubi Fatima-Zahra , Grieco Gaetano , Iodice Carmine , Caso Lucio , Ouizgane Anouar , El Moujtahid Aziz El , El Ghizi Sara El , Bousseba Meriem , Hasnaoui Mustapha , Iodice Annalaura , Tramice Annabella
Published: March 2023

Fishes are an important component of human nutrition, mainly acting as source of essential fatty acids in the prevention of cardiovascular disorders. The increase in their consumption has led to a growth of fishes waste; therefore, the disposal and recycling of waste has become a key issue to address, in accordance with circular economy principles. The Moroccan Hypophthalmichthys molitrix and Cyprinus carpio fishes, living in freshwater and marine environments, were collected at mature and immature stages. The fatty acid (FA) profiles of liver and ovary tissues were investigated by GC–MS and compared with edible fillet tissues. The gonadosomatic index, the hypocholesterolemic/hypercholesterolemic ratio, and the atherogenicity and thrombogenicity indexes were measured. Polyunsaturated fatty acids were found to be abundant in the mature ovary and fillet of both species, with a polyunsaturated fatty acids/saturated fatty acids ratio ranging from 0.40 to 1.06 and a monounsaturated fatty acids/polyunsaturated fatty acids ratio between 0.64 and 1.84. Saturated fatty acids were found to be highly abundant in the liver and gonads of both species (range 30–54%), as well as monounsaturated fatty acids (range 35–58%). The results suggested that the exploitation of fish wastes, such as the liver and ovary, may represent a sustainable strategy for the achievement of high value-added molecules with nutraceutical potential.
Bioconversion of Cheese Whey and Food By-Products by Phaeodactylum tricornutum into Fucoxanthin and n-3 Lc-PUFA through a Biorefinery Approach
Authors: Russo Giovanni Luca , Langellotti Antonio Luca , Verardo Vito , Martín-García Beatriz , Oliviero Maria , Baselice Marco , Di Pierro Prospero , Sorrentino Angela , Viscardi Sharon , Marileo Luis , Sacchi Raffaele , Masi Paolo
Published: March 2023

This study investigates the potential of utilizing three food wastes: cheese whey (CW), beet molasses (BM), and corn steep liquor (CSL) as alternative nutrient sources for the cultivation of the diatom Phaeodactylum tricornutum, a promising source of polyunsaturated eicosapentaenoic acid (EPA) and the carotenoid fucoxanthin. The CW media tested did not significantly impact the growth rate of P. tricornutum; however, CW hydrolysate significantly enhances cell growth. BM in cultivation medium enhances biomass production and fucoxanthin yield. The optimization of the new food waste medium was conducted through the application of a response surface methodology (RSM) using hydrolyzed CW, BM, and CSL as factors. The results showed a significant positive impact of these factors (p < 0.005), with an optimized biomass yield of 2.35 g L−1 and a fucoxanthin yield of 3.64 mg L−1 using a medium composed of 33 mL L−1 of CW, 2.3 g L−1 of BM, and 2.24 g L−1 of CSL. The experimental results reported in this study showed that some food by-products from a biorefinery perspective could be utilized for the efficient production of fucoxanthin and other high-added-value products such as eicosapentaenoic acid (EPA).
Subsequent Domino Osteoporotic Vertebral Fractures Adversely Affect Short-Term Health-Related Quality of Life: A Prospective Multicenter Study
Authors: Kusukawa Tomoyuki , Maruo Keishi , Toi Masakazu , Yamaura Tetsuto , Hatano Masaru , Nagao Kazuma , Oishi Hayato , Horinouchi Yutaka , Arizumi Fumihiro , Kishima Kazuya , Yoshie Norichika , Tachibana Toshiya
Published: March 2023

Background and Objectives: Conservative treatment is the gold standard for acute osteoporotic vertebral fractures (AOVFs). However, the treatment strategy for multiple AOVFs remains unknown. We conducted a prospective study using magnetic resonance imaging (MRI) to investigate how rapidly subsequent osteoporotic vertebral fractures (OVFs) occur as domino OVFs within 3 months. This study aimed to assess the incidence and impact of domino OVFs on quality of life (QOL) following conservative treatment for initial AOVFs. Materials and Methods: A prospective multicenter cohort study was conducted at eight hospitals. The included patients were those with AOVFs occurring within 3 weeks, aged >60 years, and diagnosed using MRI. All patients were treated conservatively and underwent MRI after 3 months. Subsequent domino OVFs were defined as newly occurring OVFs within 3 months. Patient characteristics, types of conservative treatment, and patient-reported outcomes, including a visual analogue scale (VAS), the Oswestry disability index (ODI), and the Japanese Orthopaedic Association back pain evaluation questionnaire (JOABPEQ), were evaluated and compared between the domino OVF and non-domino OVF groups. Results: A total of 227 patients were analyzed. The mean age was 80.1 ± 7.3 years and 78% were female. Subsequent domino OVFs were observed in 31 (13.6%) patients within 3 months. An increasing number of prevalent OVFs were significantly associated with domino OVFs (p = 0.01). No significant differences in bone mineral density, type of brace, and anti-osteoporosis medications were found between the two groups. The JOABPEQ (excluding social function), ODI, and VAS were significantly improved after 3 months. Patients with domino OVFs at 3 months had poorer JOABPEQ social life function, ODI, and VAS than those with non-domino OVFs. Conclusions: In this study, the incidence of domino OVFs was 13.6% within 3 months. Domino OVFs had a negative impact on QOL at 3 months and were associated with prevalent OVFs.
SARS-CoV-2 Protein S Fusion Peptide Is Capable of Wrapping Negatively-Charged Phospholipids
Authors: Villalaín José
Published: March 2023

COVID-19, caused by SARS-CoV-2, which is a positive-sense, single-stranded RNA enveloped virus, emerged in late 2019 and was declared a worldwide pandemic in early 2020 causing more than 600 million infections so far and more than 6 million deaths in the world. Although new vaccines have been implemented, the pandemic continues to impact world health dramatically. Membrane fusion, critical for the viral entry into the host cell, is one of the main targets for the development of novel antiviral therapies to combat COVID-19. The S2 subunit of the viral S protein, a class I membrane fusion protein, contains the fusion domain which is directly implicated in the fusion mechanism. The knowledge of the membrane fusion mechanism at the molecular level will undoubtedly result in the development of effective antiviral strategies. We have used all-atom molecular dynamics to analyse the binding of the SARS-CoV-2 fusion peptide to specific phospholipids in model membranes composed of only one phospholipid plus cholesterol in the presence of either Na+ or Ca2+. Our results show that the fusion peptide is capable of binding to the membrane, that its secondary structure does not change significantly upon binding, that it tends to preferentially bind electronegatively charged phospholipids, and that it does not bind cholesterol at all. Understanding the intricacies of the membrane fusion mechanism and the molecular interactions involved will lead us to the development of antiviral molecules that will allow a more efficient battle against these viruses.
Synergistic Effect of RE (La, Er, Y, Ce) and Al-5Ti-B on the Microstructure and Mechanical Properties of 6111Aluminum Alloy
Authors: Meng Chuanchao , Su Changchao , Liu Zhenkuan , Liao Dongxing , Rong Xincheng , Li Yuanzhuo , Tang Hongqun , Wang Junsheng
Published: March 2023

For aluminum alloys, grain refinement is one of the effective methods for improving both strength and ductility. However, the refining effect of Al-Ti-B master alloy refiners deteriorates due to the agglomeration and sinking of the second phase particles. In this paper, the effects of rare earth type, rare earth content, and holding time on the microstructure and properties of Al-5Ti-B + RE/6111 were investigated by orthogonal experiment. It was shown that the addition of rare earth promoted the transformation of the β-Al5FeSi phase to anα-Al15(Mn,Fe)3Si2 phase, while the segregation of rare earth made it difficult for TiB2 to aggregate and inhibited the growth of TiAl3, resulting in more particles becoming effective nucleation substrates. The Al-5Ti-B + Ce master alloy developed based on orthogonal experiment improved the refinement recession problem well and improved the comprehensive mechanical properties of 6111 aluminum alloy. It was found that the addition of Al-5Ti-B + 0.1Ce, which had an ultimate tensile strength of 240.4 ± 2.2 MPa, successfully reduced the grain size by 73.8% and improved elongation by 37.8% compared to the base alloy. There search is of great significance for the preparation and application of high-performance rare earth 6111 aluminum alloy.
Effect of Mask Geometry Variation on Plasma Etching Profiles
Authors: Bobinac Josip , Reiter Tobias , Piso Julius , Klemenschits Xaver , Baumgartner Oskar , Stanojevic Zlatan , Strof Georg , Karner Markus , Filipovic Lado
Published: March 2023

It is becoming quite evident that, when it comes to the further scaling of advanced node transistors, increasing the flash memory storage capacity, and enabling the on-chip integration of multiple functionalities, “there’s plenty of room at the top”. The fabrication of vertical, three-dimensional features as enablers of these advanced technologies in semiconductor devices is commonly achieved using plasma etching. Of the available plasma chemistries, SF6/O2 is one of the most frequently applied. Therefore, having a predictive model for this process is indispensable in the design cycle of semiconductor devices. In this work, we implement a physical SF6/O2 plasma etching model which is based on Langmuir adsorption and is calibrated and validated to published equipment parameters. The model is implemented in a broadly applicable in-house process simulator ViennaPS, which includes Monte Carlo ray tracing and a level set-based surface description. We then use the model to study the impact of the mask geometry on the feature profile, when etching through circular and rectangular mask openings. The resulting dimensions of a cylindrical hole or trench can vary greatly due to variations in mask properties, such as its etch rate, taper angle, faceting, and thickness. The peak depth for both the etched cylindrical hole and trench occurs when the mask is tapered at about 0.5°, and this peak shifts towards higher angles in the case of high passivation effects during the etch. The minimum bowing occurs at the peak depth, and it increases with an increasing taper angle. For thin-mask faceting, it is observed that the maximum depth increases with an increasing taper angle, without a significant variation between thin masks. Bowing is observed to be at a maximum when the mask taper angle is between 15° and 20°. Finally, the mask etch rate variation, describing the etching of different mask materials, shows that, when a significant portion of the mask is etched away, there is a notable increase in vertical etching and a decrease in bowing. Ultimately, the implemented model and framework are useful for providing a guideline for mask design rules.
Design and Characterization of an Adjustable Passive Flow Regulator and Application to External CSF Drainage
Authors: Chappel Eric
Published: March 2023

Passive valves that deliver a constant flow rate regardless of inlet pressure changes have numerous applications in research, industry, and medical fields. The present article describes a passive spring valve that can be adjusted manually to deliver the required flow rate. The valve consists of a movable rod with an engraved microchannel. The fluidic resistance of the device varies together with the inlet pressure to regulate the flow rate. A prototype was made and characterized. Flow-rate adjustment up to +/−30% of the nominal flow rate was shown. A simple numerical model of the fluid flow through the device was made to adapt the design to external ventricular drainage of cerebrospinal fluid (CSF). Some insights about the implementation of this solution are also discussed.
Improving Etched Flatness by Micro Airflow Array Pressurization in ITO Glass Laser Machining
Authors: Chen Rong , Chen Zhaojie , Xie Jin
Published: March 2023

In laser etching of ITO glass, the warpage due to workpiece positioning causes breakpoint or deformation of micron-scale etching circuits. Based on traditional laser etching, a micro-airflow array pressurization is proposed by using a micro-flow air bearing through airflow positioning. The objective is to achieve high-precision laser etching by pressurized micro-deformation of ITO glass during positioning. First, the micro-air flow and pressurized micro-deformation were modelled in relation to the airflow pressure and etching gap in order to analyze the flatness variation behavior. Then, the surface flatness was investigated in relation to the airflow parameters and relative bearing location. Finally, the critical value of the pressurization parameter were calculated using a data-twin and were applied to industrial ITO glass etching. It is shown that the uniform flow pressure distribution and surface central micro-deformation were formed by positive airflow pressure in the airflow area. The airflow pressure and etching gap could promote surface flatness, while excessive values could result in excessive deformation. Under the micro flow pressure, the initial flatness of the workpiece was able to be compensated within the critical pressurization parameter. By controlling the micro flow stress, the micro-airflow array pressurization could reduce the flatness to 22 μm with stress of 10.7–12.6 Pa. In industrial production, the surface fine circuits can be laser etched with an optimized micro flow pressure, which solves the problems of local breaks or deformed circuits due to the conventional etching process and the structural layout.