Computer-aided design of graphene and 2D materials synthesis via magnetic inductive heating of eleven transition metals

2021 ◽  
Author(s):  
Elyes Dhaouadi ◽  
Ivaylo Hinkov ◽  
Katya Pashova ◽  
Nabil Challab ◽  
Yves Roussigne ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Large Scale ◽  
2D Materials ◽  
Growth Conditions ◽  
Skin Depth ◽  
Process Efficiency ◽  
Monolayer Graphene ◽  
Transient Temperature ◽  
Inductive Heating ◽  
Metal Foils

Abstract We performed numerical simulations to determine the effect of the most influential operating parameters on the performance of radio frequency (RF) induction heating system in which RF magnetic fields inductively heat metal foils to grow graphene. Thermal efficiency of the system depends on the geometry as well as on the material electrical conductivity and skin depth. The process is simulated under specific graphene and 2D materials growth conditions using finite elements software in order to predict transient temperature and magnetic field distribution during standard graphene and 2D materials growth conditions. The proposed model considers different coil Helmholtz-like geometries and eleven metal foils including Ag, Au, Cu, Ni, Co, Pd, Pt, Rh, Ir, Mo and W. In each case, an optimal window of process variables ensuring a temperature range of 1035–1084 °C or 700–750 °C suitable for graphene and MoS2 growth respectively was found. Temperature gradient calculated from the simulated profiles between the edge and the center of the substrate showed a thermal uniformity of less than ~2% for coinage metals like Au, Ag and Cu and up to 7% for Pd. Model validation was performed for graphene growth on copper. Due to its limited heat conductivity, good heating uniformity was obtained. As a consequence, full coverage of monolayer graphene on copper with few defects and grain domain size of ~2 µm is obtained. Substrate temperature reached ~ 1035 ° C from ambient after only ~90 s, in excellent agreement with model predictions. This allows for improved process efficiency in terms of fast, localized, homogeneous and precise heating with energy saving. Due to these advantages, inductive heating has great potential for large scale and rapid manufacturing of graphene and 2D materials.

scholarly journals Analysis of Subsynchronous Torsional of Wind–Thermal Bundled System Transmitted via HVDC Based on Signal Injection Method

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 474
Author(s):  
Junxi Wang ◽  
Qi Jia ◽  
Gangui Yan ◽  
Kan Liu ◽  
Dan Wang
Keyword(s):  
Wind Power ◽  
High Voltage ◽  
Direct Current ◽  
Computer Aided Design ◽  
Large Scale ◽  
Electromagnetic Transients ◽  
Torsional Mode ◽  
High Voltage Direct Current ◽  
Operation Conditions ◽  
Signal Injection

With the development of large-scale new energy, the wind–thermal bundled system transmitted via high-voltage direct current (HVDC) has become the main method to solve the problem of wind power consumption. At the same time, the problem of subsynchronous oscillation among wind power generators, high-voltage direct current (HVDC), and synchronous generators (SGs) has become increasingly prominent. According to the dynamic interaction among doubly fed induction generators (DFIGs), HVDC, and SGs, a linearization model of DFIGs and SGs transmitted via HVDC is established, and the influence of the electromagnetic transient of wind turbines and HVDC on the electromechanical transient processes of SGs is studied. Using the method of additional excitation signal injection, the influence of the main factors of DFIG on the damping characteristics of each torsional mode of SG is analyzed, including control parameters and operation conditions when the capacity of HVDC is fixed. The mechanism of the negative damping torsional of SGs is identified. A time-domain simulation model is built in Electromagnetic Transients including DC/Power Systems Computer Aided Design (EMTDC/PSCAD) to verify the correctness and effectiveness of the theoretical analysis.

scholarly journals Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 601
Author(s):  
Dinh-Tuan Nguyen ◽  
Hsiang-An Ting ◽  
Yen-Hsun Su ◽  
Mario Hofmann ◽  
Ya-Ping Hsieh
Keyword(s):  
Large Scale ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Spectroscopic Characterization ◽  
High Yield ◽  
Nanometer Scale ◽  
Efficient Production ◽  
Device Performance ◽  
Metal Dichalcogenides ◽  
Scale Deposition

The success of van-der-Waals electronics, which combine large-scale-deposition capabilities with high device performance, relies on the efficient production of suitable 2D materials. Shear exfoliation of 2D materials’ flakes from bulk sources can generate 2D materials with low amounts of defects, but the production yield has been limited below industry requirements. Here, we introduce additive-assisted exfoliation (AAE) as an approach to significantly increase the efficiency of shear exfoliation and produce an exfoliation yield of 30%. By introducing micrometer-sized particles that do not exfoliate, the gap between rotor and stator was dynamically reduced to increase the achievable shear rate. This enhancement was applied to WS2 and MoS2 production, which represent two of the most promising 2D transition-metal dichalcogenides. Spectroscopic characterization and cascade centrifugation reveal a consistent and significant increase in 2D material concentrations across all thickness ranges. Thus, the produced WS2 films exhibit high thickness uniformity in the nanometer-scale and can open up new routes for 2D materials production towards future applications.

scholarly journals Xanthones Production in Gentiana dinarica Beck Hairy Root Cultures Grown in Simple Bioreactors

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1610
Author(s):  
Branka Vinterhalter ◽  
Nevena Banjac ◽  
Dragan Vinterhalter ◽  
Dijana Krstić-Milošević
Keyword(s):  
Hairy Root ◽  
Large Scale ◽  
Bubble Column ◽  
Growth Parameters ◽  
Growth Index ◽  
Dry Weight ◽  
Growth Conditions ◽  
Good Growth ◽  
Gentiana Dinarica ◽  
Hairy Root Clones

The hairy root clones of Gentiana dinarica cl-B, cl-D, cl-3, and cl-14 were cultivated in parallel in diverse simple bioreactors, including temporary immersion systems RITA® (TIS RITA®), bubble column bioreactors (BCB), and Erlenmeyer flasks (EF), and evaluated for biomass production and xanthone content. The obtained results showed that TIS RITA® and BCB containing ½ MS medium with 4% sucrose provided equally good growth conditions in which the majority of the clones displayed the higher percentage of dry matter (DM%), and xanthones norswertianin-1-O-primeveroside (nor-1-O-prim) and norswertianin production than those cultivated in EF. Thin and well branched hairy root clone cl-B grown in BCB for 7 weeks was superior regarding all growth parameters tested, including growth index (19.97), dry weight (2.88 g), and DM% (25.70%) compared to all other clones. Cl-B cultured in TIS RITA® contained the highest amount of nor-1-O-prim (56.82 mg per vessel). In BCB with constant aeration, cl-B accumulated the highest norswertianin content reaching 18.08 mg/vessel. The optimized conditions for cultivation of selected G. dinarica hairy root clones in highly aerated TIS RITA® and BCB systems contribute to the development of bioreactor technology designed for the large scale commercial production of xanthones nor-1-O-prim and norswertianin.

scholarly journals Large-scale selection synchrony of Tetrahymena thermophila

1986 ◽  
Vol 84 (1) ◽  
pp. 237-251
Author(s):  
R.J. Hill ◽  
T. Kroft ◽  
M. Zuker ◽  
I.C. Smith
Keyword(s):  
Cell Cycle ◽  
Cell Culture ◽  
Cell Population ◽  
Large Scale ◽  
Doubling Time ◽  
Tetrahymena Thermophila ◽  
Growth Conditions ◽  
Scale Selection

A method is described, based on the phagocytosis of colloidal ferrite particles, which gives highly synchronous populations of Tetrahymena thermophila. To ensure a successful synchrony, the cell culture doubling time, the limits of the phagocytic period and the distribution of cell stages must first be determined. Once these parameters are known, synchrony can be achieved under a variety of growth conditions and with cultures ranging in volume from a few millilitres to 12 litres or more. The main advantages of the method are that the apparatus required is simple, large volumes of cells can be handled easily, and the synchronous populations can be prepared within a few hours. In principle, the method should be applicable to any cell population in which phagocytosis occurs discontinuously over the cell cycle.

scholarly journals Chromosomal Rearrangements in Salmonella enterica Serovar Typhi Strains Isolated from Asymptomatic Human Carriers

mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
T. David Matthews ◽  
Wolfgang Rabsch ◽  
Stanley Maloy
Keyword(s):  
Salmonella Enterica ◽  
Large Scale ◽  
Chromosomal Rearrangements ◽  
Growth Conditions ◽  
Genetic Changes ◽  
Content Type ◽  
Long Term Storage ◽  
Bacterial Chromosomes ◽  
Over Time

ABSTRACTHost-specific serovars ofSalmonella entericaoften have large-scale chromosomal rearrangements that occur by recombination betweenrrnoperons. Two hypotheses have been proposed to explain these rearrangements: (i) replichore imbalance from horizontal gene transfer drives the rearrangements to restore balance, or (ii) the rearrangements are a consequence of the host-specific lifestyle. Although recent evidence has refuted the replichore balance hypothesis, there has been no direct evidence for the lifestyle hypothesis. To test this hypothesis, we determined therrnarrangement type for 20Salmonella entericaserovar Typhi strains obtained from human carriers at periodic intervals over multiple years. These strains were also phage typed and analyzed for rearrangements that occurred over long-term storage versus routine culturing. Strains isolated from the same carrier at different time points often exhibited different arrangement types. Furthermore, colonies isolated directly from the Dorset egg slants used to store the strains also had different arrangement types. In contrast, colonies that were repeatedly cultured always had the same arrangement type. Estimated replichore balance of isolated strains did not improve over time, and some of the rearrangements resulted in decreased replicore balance. Our results support the hypothesis that the restricted lifestyle of host-specificSalmonellais responsible for the frequent chromosomal rearrangements in these serovars.IMPORTANCEAlthough it was previously thought that bacterial chromosomes were stable, comparative genomics has demonstrated that bacterial chromosomes are dynamic, undergoing rearrangements that change the order and expression of genes. While mostSalmonellastrains have a conserved chromosomal arrangement type, rearrangements are very common in host-specificSalmonellastrains. This study suggests that chromosome rearrangements in the host-specificSalmonella entericaserovar Typhi, the causal agent of typhoid fever, occur within the human host over time. The results also indicate that rearrangements can occur during long-term maintenance on laboratory medium. Although these genetic changes do not limit survival under slow-growth conditions, they may limit the survival ofSalmonellaTyphi in other environments, as predicted for the role of pseudogenes and genome reduction in niche-restricted bacteria.

Full-Layer Controlled Synthesis and Transfer of Large-Scale Monolayer Graphene for Nitrogen Dioxide and Ammonia Sensing

2013 ◽  
Vol 47 (2) ◽  
pp. 280-294 ◽  
Author(s):  
Vu Van Quang ◽  
Ngo Si Trong ◽  
Nguyen Ngoc Trung ◽  
Nguyen Duc Hoa ◽  
Nguyen Van Duy ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Large Scale ◽  
Monolayer Graphene ◽  
Controlled Synthesis ◽  
Ammonia Sensing

Physical Modeling for Selective Laser Sintering Process

2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Arash Gobal ◽  
Bahram Ravani
Keyword(s):  
Physical Modeling ◽  
Large Scale ◽  
Selective Laser Sintering ◽  
Powdered Material ◽  
Laser Sintering ◽  
Industrial Applications ◽  
Transient Temperature ◽  
Sintering Process ◽  
Powder Bed ◽  
Selective Heating

The process of selective laser sintering (SLS) involves selective heating and fusion of powdered material using a moving laser beam. Because of its complicated manufacturing process, physical modeling of the transformation from powder to final product in the SLS process is currently a challenge. Existing simulations of transient temperatures during this process are performed either using finite-element (FE) or discrete-element (DE) methods which are either inaccurate in representing the heat-affected zone (HAZ) or computationally expensive to be practical in large-scale industrial applications. In this work, a new computational model for physical modeling of the transient temperature of the powder bed during the SLS process is developed that combines the FE and the DE methods and accounts for the dynamic changes of particle contact areas in the HAZ. The results show significant improvements in computational efficiency over traditional DE simulations while maintaining the same level of accuracy.

Ultrasensitive broadband photodetectors based on two-dimensional Bi2O2Te films

2021 ◽  
Author(s):  
Pin Tian ◽  
Hongbo Wu ◽  
Libin Tang ◽  
Jinzhong Xiang ◽  
Rongbin Ji ◽  
...  
Keyword(s):  
Large Scale ◽  
2D Materials ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Technology ◽  
Photocurrent Density ◽  
Short Wave ◽  
Oxide Semiconductor ◽  
Light Illumination ◽  
Two Dimensional ◽  
Weak Light

Abstract Two-dimensional (2D) materials exhibit many unique optical and electronic properties that are highly desirable for application in optoelectronics. Here, we report the study of photodetector based on 2D Bi2O2Te grown on n-Si substrate. The 2D Bi2O2Te material was transformed from sputtered Bi2Te3 ultrathin film after rapid annealing at 400 ℃ for 10 min in air atmosphere. The photodetector was capable of detecting a broad wavelength from 210 nm to 2.4 μm with excellent responsivity of up to 3x105 and 2x104 AW-1, and detectivity of 4x1015 and 2x1014 Jones at deep ultraviolet (UV) and short-wave infrared (SWIR) under weak light illumination, respectively. The effectiveness of 2D materials in weak light detection was investigated by analysis of the photocurrent density contribution. Importantly, the facile growth process with low annealing temperature would allow direct large-scale integration of the 2D Bi2O2Te materials with complementary metal-oxide–semiconductor (CMOS) technology.

Sign in / Sign up

Export Citation Format

Share Document