bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of nanoparticles on melting and solidification during a Directed Energy Deposition process analysed by simulation
Authors: Zheng G , Laqua R , Rey P , Salgueiro M , Gipperich M , Riepe J , Jakumeit J 
Published: March 2023

Abstract
Additive Manufacturing is a strategic tool for industrial applications. When large size structural parts are targeted, high deposition rates are important and Directed Energy Deposition (DED) is a preferred technique. A metal wire is melted by laser light and deposit on a substrate or already solidified material. Due to the small size of the melting zone, a detailed experimental analysis of the process is very difficult and simulation is an important tool to understand the manufacturing process and the influence of process and material parameter. Here the influence of the nanocomposite reinforcement on the deposition process are investigated by simulation single line tracks. A three-phase melting and solidification simulation methodology has been used to investigate the melting and solidification during DED printing of single line tracks of different wire materials. The approach uses the finite-volume method and arbitrary polyhedral control volumes to solve the governing equations. Heating of the wire by laser light is tackled using a volumetric heat source describing the specific absorption of the laser power by the metal wire. The influence of melting and solidification on the initially uniform nanocomposite distribution during the printing process is simulated using a Lagrangian approach. Firstly, simulations for steel ST 52-3 (1.0570) were performed for different process parameter settings and compared to experimental results of deposition width, height and form to validate the simulation approach. The method is then applied to Ti6Al4V wires with and without nanocomposites added to the wire material. Adding nanocomposites changes the melting and solidification behaviour of the wire materials. The influence of these changes of the material properties on the deposition process under different process conditions is analysed by simulation.
Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical concentration by Laser-Induced Breakdown Spectroscopy (LIBS)
Authors: Quackatz L , Griesche A , Kannengiesser T 
Published: March 2023

Abstract
Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process.
Thermomechanical analysis of the solidification of fused cast alumina-zirconia-silica refractory blocks
Authors: Houdard T , Cabodi I , Vespa P , Pigeonneau F , Gandin C-A 
Published: March 2023

Abstract
Cooling history of fused cast Alumina-Zirconia-Silica (AZS) refractory blocks is recorded with thermocouples. Postmortem investigations are performed including hot tears. Discussion about solidification path is done with the purpose to better understand phenomena occurring during casting. Heat transfer simulations are compared with recorded temperature histories. Mechanical outputs from THERCAST® are analyzed, revealing the possibility to calibrate the risk of hot tears formation by considering a cumulated strain based criterion.
Modeling the Fluid Flow for Recent Solidification Experiments in Microgravity Electromagnetic Levitation
Authors: Bracker G P , Hyers R W 
Published: March 2023

Abstract
Microgravity electromagnetic levitation provides a unique processing environment for solidification experiments. The contactless processing allows for greater access to the undercooled region of the melt by isolating the sample from its environment and reducing the available heterogeneous nucleation to consistently achieve deep undercoolings. In the ISS-EML, a variety of solidification studies have investigated the relationship between nucleation temperature and flow conditions in metallic melts. These studies include recent work by Kelton et al. in which the coupled flux nucleation model was used to explore solidification in supercooled liquids using glass forming alloys: Vit106, Cu50Zr50, and Ti39.5Zr39.5Ni21. The relationship between fluid flow and nucleation is also a critical factor in recent experiments investigating dynamic nucleation. Unexplained solidification events occurred during both Spacelab Missions IML-2, MSL-1R, and ISS-EML. These experiments encompassed both steady and transient, accelerating flows. Repeatable, anomalous solidification was observed in both flow conditions. The conditions are consistent with dynamic nucleation, which relies heavily on the flow conditions within the sample for nucleation to occur. During these experiments, flow is not directly observable; however, magnetohydrodynamic models allow the flow to be calculated using the properties of the melt and the experimental conditions. These models provide key insights into the flow conditions and the impacts of flow on nucleation in these experiments.
High-precision solidification simulation by estimating heat transfer coefficients through data assimilation
Authors: Natsume Y , Oikawa T , Ohno M 
Published: March 2023

AbstractSolidification analysis is important for accurately predicting casting processes. A high-precision casting simulation requires accurate data of the physical properties of materials and heat transfer parameters. In particular, the heat transfer coefficient is a major parameter influencing the casting simulation results. Because the heat transfer coefficient is not uniquely determined by the material, it is typically estimated by trial and error, which requires considerable time for accurate estimations. Therefore, we developed a method to quickly estimate the heat transfer coefficient in a casting process by combining data assimilation and solidification simulations. With this method, the time-dependent heat transfer coefficient can be estimated in an appropriate and easy manner. To reproduce the 3D temperature distribution in a casting with high accuracy, we developed a method to estimate multiple heat transfer coefficients simultaneously by combining data assimilation and 3D solidification simulation. Al–5 mass% Si alloy was cast into a sand mold with a casting size of 30 mm × 30 mm × 100 mm, and the temperature was measured at five points in the casting to obtain a cooling curve. Two cooling curves corresponding to locations of 5 mm from the casting wall were used to estimate the two heat transfer coefficients on the side and bottom surfaces, which were simultaneously estimated by data assimilation. The results confirmed that all the five cooling curves could be reproduced with a high accuracy and that high-precision casting simulation was possible.
The effect of Sr modification on the eutectic structure of AlSi7Mg alloys at different purity levels
Authors: Gursoy Ozen , Timelli Giulio 
Published: March 2023

Abstract
The effect of different Sr levels on the solidification path and the microstructure of the Al-Si eutectic in AlSi7Mg alloys at 3 different levels of purity (high purity, commercial purity, and secondary alloy) was investigated. Thermal analysis technique was performed to obtain the cooling curves and characteristic temperatures of the eutectic reactions. Microstructural investigations were carried out to study the variation of the eutectic structure due to Sr addition and alloy’s purity. The results indicate how the commercially pure alloy shows the highest nucleation and growth temperatures among the unmodified alloys, while the secondary alloy has the lowest ones. Sr addition decreases the characteristic eutectic temperatures. Even though the growth temperature is similar after Sr modification in the commercial and high purity alloys, this last shows a finest eutectic structure. Different levels of Sr are required to fully modify the eutectic of the AlSi7Mg alloy at different purity grade.
On the role of interfacial segregation on graphite shape in cast irons
Authors: Lacaze J 
Published: March 2023

Abstract
Understanding spheroidal graphite growth in cast irons is a long standing problem for which several mechanisms have been proposed. During the last decade, observations using transmission electron microscopy added new information about the stacking of graphite layers, leading eventually to propose other mechanisms than previously thought of such as repeated 2D-nucleation of new growth blocks and their lateral extension at the surface of the spheroids. Furthermore, it has been recently realized that elements known to strongly affect graphite shape are also those that are surface active. This is illustrated here in the case of antimony which is known to lead to spheroidal graphite degeneration when added at some tens of ppm. Using atomic resolution microscopy, segregation of antimony could be evidenced at the graphite/matrix interface of both spheroids and protuberances. This strongly suggests that accumulation of antimony repelled magnesium from the graphite surface until growth of spiky protuberances replaced spheroidal growth.
Simulation of macrosegregation in continuous casting of steel based on large-eddy simulation turbulence model and meshless solution procedure
Authors: Mramor K , Vertnik R , Šarler B 
Published: March 2023

Abstract
The formation of macrosegregation pattern in steel is explored for the continuous casting process. The related solidification problem is described by incompressible turbulent fluid flow, governed by mass, momentum, energy, and species conservation equations. The solid-liquid system is designed in a mixture continuum model formulation, and the mushy region is approximated with the Darcy model. The lever rule describes the formation of microsegregation of carbon. Turbulence is modelled with a large-eddy simulation approach implemented with the Smagorinsky model and van Driest correction. The synthetic isotropic fluctuations of the inlet velocity are generated by the von Karman Pao spectrum. The solution of partial differential equations is implemented locally by using collocation with radial basis functions for spatial discretization and the explicit Euler method for time discretization. The two-dimensional large eddy simulation model solutions are compared to the previously calculated examples obtained with the low-Re k − ε turbulence model.
Observation of grain motion during semisolid deformation by using 4D-CT and 3DXRD
Authors: Narumi T , Ohta K , Ohta M , Numata T , Asahi K , Katsube R , Yasuda H 
Published: March 2023

Abstract
A technique combining time-resolved computed tomography (4D-CT) and three-dimensional X-ray diffraction (3DXRD) was employed to investigate semisolid deformation in an Al-10mass%Cu alloy with the equiaxed grain structure. The diffraction patterns and reconstructed 3D images were used to quantitatively analyse the translational and rotational motions of solid grains in the semisolid alloy. Finally, the motion of solid grains and the expansion of porosity during the compression tests are discussed on the basis of in situ observations.
Investigation of Al-20Sn-10Cu alloy directional solidification by laboratory X-radiography
Authors: Reinhart G , Ngomesse F , Bertelli F. , Benigni P , Campos A , Nguyen-Thi H 
Published: March 2023

Abstract
Al-based alloys with a soft phase such as Sn are extensively used for bearing components due to their self-lubricating properties. Al-Sn alloys lack the ability to support heavy loads so the alloying with Cu as a third element provides solution strengthening of the aluminium matrix. A crucial issue in the manufacturing of Al-Sn-Cu alloys is the miscibility gap in the phase diagram of the system. Liquid immiscibility is responsible for severe segregation during the solidification process, due to the large density difference between the Al-rich and Sn-rich liquids, which limits their utilization in industry. It is therefore both scientifically and technically important to accurately understand their solidification path. In the present work, the solidification of a ternary Al-20wt.%Sn-10wt.%Cu alloys was investigated in-situ by using X-radiography. Directional solidification experiments were performed on sheet-like samples in the laboratory device SFINX (Solidification Furnace with IN-situ X-radiography), which consists of a Bridgman-type gradient furnace and an X-radiography system. The solidification sequence was determined based on the observation of the recorded images, enlightening the successive steps of the solidification path. These observations were compared to predictions obtained from thermodynamic calculations. Complementary post-mortem microscopic analyses showed that the dendrite primary trunk and secondary arms developed along <110> crystallographic axes instead of the usually expected <100>.
Microstructural Characterization and Mechanical Properties Investigation of Nemalloy HE700 alloy: Effect of Pre-Solidified Grains
Authors: Aziz T. , Sadayappan K. , Phillion A. , Shankar S. 
Published: March 2023

Abstract
Structural plate castings of Nemalloy HE700 alloy, an Al-Fe eutectic alloy system with Zn and Mg as precipitation strengtheners were produced through high vacuum high pressure die casting (HVHPDC) and designed as an alternative to existing structural automotive materials. Cast materials are subject to the existence of pre-solidified grains (PSG) within the microstructure that originate from external solidification in the liquid melt and cause defects in the final cast components. In the case of HPDC, these PSG emerge in the shot sleeve and are injected through the gating system, influencing liquid metal flow behaviour and solidification characteristics. The extent of PSG and their distribution were manipulated through the altering of process route parameters such as shot delay intervals. Quantitative metallography and the effect of PSGs on the uniaxial tensile properties for the Nemalloy HE700 alloy are presented in this publication.
Green preparation of carbon fiber/liquid silicone rubber composites for flexible electrode
Authors: Liu Zhitao , Ma Lichun , Wang Xiaoran , Zheng Hao , Peng Zhi , Zhu Junjie , Song Guojun 
Published: March 2023

Abstract
Stretchable flexible conductive polymer composites (flexible electrodes) had become a research hot spot. In this paper, two-component room-temperature vulcanized liquid silicone rubber (LRTV) and short carbon fibers (CFs) were mixed by mechanical blending without solvent to prepare a tensile self-reply composites with high conductivity. The relationships between the average length, length distribution and content of CFs and the performance of CFs/LRTV composites were investigated. When the CFs length was 100 μm, the composites achieved a high conductivity. The composites conductivity threshold was reached when the CFs content was 3 wt%. In addition, the composites could be used as a conductor to light the bulb when the CFs content reached 8 wt%. The conductivity remained stable during cyclic stretching with a strain of 8%. The breaking and reconstruction of the internal 3D conductive network in the composites during the stretching process were discovered. The obtained results revealed that CFs/LRTV composites can be used as highly effective, flexible, stretchable electrode materials for stretchable displays, electronic skin, personalized healthcare.
Novel Technology for Facial Muscle Stimulation Combined With Synchronized Radiofrequency Induces Structural Changes in Muscle Tissue: Porcine Histology Study
Authors: Kinney Brian M , Bernardy Jan , Jarošová Rea 
Published: March 2023

Abstract

Background
With age, facial muscles lose the ability to complete contractions properly, resulting in limitation of facial expressions and fat shifting, and leading to skin creases and wrinkling.

Objectives
The aim of this study was to determine the effects of the novel high intensity facial electromagnetic stimulation (HIFES) technology combined with synchronized radiofrequency on delicate facial muscles, using an animal porcine model.

Methods
Eight (n = 8, 60-80 kg) sows were divided into the active group (n = 6) and the control group (n = 2). The active group underwent four 20-minute treatments with radiofrequency (RF) and HIFES energies. The control group was not treated. Histology samples of muscle tissue were collected by a punch biopsy (6 mm in diameter) from the treatment area of each animal at baseline, 1-month, and 2-month follow-up. The evaluation included staining of the obtained tissue slices with hematoxylin and eosin and Masson's trichrome to determine the changes in muscle mass density, number of myonuclei, and muscle fibers.

Results
The active group showed muscle mass density increase (by 19.2%, P &lt; .001), together with elevated numbers of myonuclei (by 21.2%, P &lt; .05) and individual muscle fibers, which increased from 56.8 ± 7.1 to 68.0 ± 8.6 (P &lt; .001). In the control group, no significant changes were seen in any of the studied parameters throughout the study (P &gt; .05). Finally, no adverse events or side effects were observed in the treated animals.

Conclusions
The results document favorable changes after the HIFES + RF procedure at the level of the muscle tissue, which may be of great importance in terms of maintenance of facial appearance in human patients.
PhaGAA: an integrated web server platform for phage genome annotation and analysis
Authors: Wu Jiawei , Liu Qingrui , Li Min , Xu Jiliang , Wang Chen , Zhang Junyin , Xiao Minfeng , Bin Yannan , Xia Junfeng 
Published: March 2023

AbstractMotivationPhage genome annotation plays a key role in the design of phage therapy. To date, there have been various genome annotation tools for phages, but most of these tools focus on mono-functional annotation and have complex operational processes. Accordingly, comprehensive and user-friendly platforms for phage genome annotation are needed.ResultsHere, we propose PhaGAA, an online integrated platform for phage genome annotation and analysis. By incorporating several annotation tools, PhaGAA is constructed to annotate the prophage genome at DNA and protein levels and provide the analytical results. Furthermore, PhaGAA could mine and annotate phage genomes from bacterial genome or metagenome. In summary, PhaGAA will be a useful resource for experimental biologists and help advance the phage synthetic biology in basic and application research.Availability and implementationPhaGAA is freely available at http://phage.xialab.info/.
No significant salt or sweet taste preference or sensitivity differences following ad libitum consumption of ultra-processed and unprocessed diets: a randomized controlled pilot study
Authors: Jaime-Lara Rosario B , Franks Alexis T , Agarwal Khushbu , Nawal Nafisa , Courville Amber B , Guo Juen , Yang Shanna , Brooks Brianna E , Roy Abhrarup , Taylor Karen , Darcey Valerie L , LeCheminant James D , Chung Stephanie , Forde Ciarán G , Hall Kevin D , Joseph Paule V 
Published: March 2023

AbstractUltra-processed food consumption has increased worldwide, yet little is known about the potential links with taste preference and sensitivity. This exploratory study aimed to (i) compare sweet and salty taste detection thresholds and preferences following consumption of ultra-processed and unprocessed diets, (ii) investigate whether sweet and salty taste sensitivity and preference were associated with taste substrates (i.e. sodium and sugar) and ad libitum nutrient intake, and (iii) examine associations of taste detection thresholds and preferences with blood pressure (BP) and anthropometric measures following consumption of ultra-processed and unprocessed diets. In a randomized crossover study, participants (N = 20) received ultra-processed or unprocessed foods for 2 weeks, followed by the alternate diet. Baseline food intake data were collected prior to admission. Taste detection thresholds and preferences were measured at the end of each diet arm. Taste-substrate/nutrient intake, body mass index (BMI), and body weight (BW) were measured daily. No significant differences were observed in participant salt and sweet detection thresholds or preferences after 2 weeks on ultra-processed or unprocessed diets. There was no significant association between salt and sweet taste detection thresholds, preferences, and nutrient intakes on either diet arm. A positive correlation was observed between salt taste preference and systolic BP (r = 0.59; P = 0.01), BW (r = 0.47, P = 0.04), and BMI (r = 0.50; P = 0.03) following consumption of the ultra-processed diet. Thus, a 2-week consumption of an ultra-processed diet does not appear to acutely impact sweet or salty taste sensitivity or preference. Trial Registration: ClinicalTrials.gov Identifier NCT03407053.