bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal-decorated γ-graphyne as a drug transporting agent for the mercaptopurine chemotherapy drug: a DFT study
Authors: Pallikkara Chandrasekharan Sreejith , Lakshmy Seetha , Sanyal Gopal , Kalarikkal Nandakumar , Trivedi Ravi , Chakraborty Brahmananda
Published: February 2023

Adsorption and desorption study of chemotherapeutic drug mercaptopurine on the pristine and metal-decorated gamma-graphyne for the potential drug delivery applications.
Computational predictions on Brønsted acidic ionic liquid-catalyzed carbon dioxide conversion to five-membered heterocyclic carbonyl derivatives
Authors: Abdullayev Yusif , Karimova Nazani , Schenberg Leonardo A. , Ducati Lucas C. , Autschbach Jochen
Published: February 2023

Ionic liquid-catalyzed CO2fixation to heterocyclic carbonyl derivatives is studied computationally. DFT and MD simulations show that carbon dioxide can be easily fixated using the utilized substrates in ionic liquid media.
Herbaceous plants-derived hydroxycinnamic units for constructing recyclable and controllable copolyesters
Authors: Shi Jia , Wang Shuizhong , Li Helong , Song Guoyong
Published: February 2023

Herbaceous plants-derived hydroxycinnamic units can serve as unique monomers to construct recyclable and controllable copolyesters via biomass RCF, one-pot derivatization, and copolymerization.
Ultrafast and continuous synthesis of phase change nanocapsules using salt-accelerated microwave-assisted polymerization
Authors: Li Dan , Li Xin , Yan Jun , Qian Yongqiang , Wang Guxia , Wei Yen , Guo Shengwei
Published: February 2023

Using a microwave-assisted polymerization method for the continuous and ultrafast preparation of nanoencapsulated phase change materials (NanoPCMs) for energy storage.
Effective removal of lead and copper ions from water using a novel sodium alginate–streptomycin sulfate composite aerogel
Authors: Zhu Chuanyu , Feng Zhongmin , Meng Yupu , Wang Min , Wang Zhuqing
Published: February 2023

An environmentally safe aerogel of sodium alginate–streptomycin sulfate was developed, which can easily separate solid and liquid.
Dopamine-coated layered Co0.85Se as an efficient bifunctional oxygen electrocatalyst
Authors: Li Jin , Zhang Yu , Wei Wenjie , Fan Gaochao , Wang Zumin , Zong Lingbo , Wang Lei
Published: February 2023

We designed Co0.85Se@NC with Se vacancies, which enables the co-facilitation of the ORR and OER.
Green synthesis of fusiform-shaped Fe-PANI as a phenomenal dual electrocatalyst for overall water splitting and assessment of its sustainability standards
Authors: Vishnu Bakthavachalam , Sriram Sundarraj , Jayabharathi Jayaraman
Published: February 2023

Development of eco-friendly dual electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is gaining importance for renewable energy generation.
Catalyst-free thiophosphorylation of in situ formed ortho-quinone methides
Authors: Ash Jeffrey , Kang Jun Yong
Published: February 2023

Thiophosphorylation of aza-o-QM and o-QM has been developed under mild conditions to synthesize functionalized thiophosphates.
Ordered stripes to crack patterns in dried particulates of DNA-coated gold colloids via modulating nanoparticle–substrate interactions
Authors: Bhattacharjee Suman , Srivastava Sunita
Published: February 2023

DNA decorated nanocolloids exhibit surface morphology transition from concentric ring to crack pattern, via tuning nanoparticle-substrate interaction.
Preparation of polymer nanoparticle-based complex coacervate hydrogels using polymerisation-induced self-assembly derived nanogels
Authors: Du Ruiling , Fielding Lee A.
Published: February 2023

pH-responsive nanogels synthesised by reversible addition-fragmentation chain-transfer mediated polymerisation-induced self-assembly were used to prepare shear-thinning polymer nanoparticle-based complex coacervate hydrogels.
Photo-switchable phosphotungstic acid active sites in metal–organic frameworks for a tailorable deacetalization reaction
Authors: Wen Hui , Liu Guoliang , Qi Shi-Chao , Gu Chen , Yang Tao , Tan Peng , Sun Lin-Bing
Published: February 2023

Tailorable catalytic activity in the deacetalization reaction can be achieved on photo-responsive MOFs through tuning the interaction between photo-responsive azobenzene motifs and phosphotungstic acid active sites via UV- and vis-light irradiation.
Competitive aminal formation during the synthesis of a highly soluble, isopropyl-decorated imine porous organic cage
Authors: Kearsey Rachel J. , Tarzia Andrew , Little Marc A. , Brand Michael C. , Clowes Rob , Jelfs Kim E. , Cooper Andrew I. , Greenaway Rebecca L.
Published: February 2023

An imine-derived isopropyl-functionalised POC was synthesised over competitive aminal formation by introducing an additional amine in the assembly process.
A bimetallic 3D interconnected metal–organic framework with 2D morphology and its derived electrocatalyst for oxygen reduction
Authors: Bao Zijia , Zhou Guojun , Liu Xinrong , Peng Yuxin , Huang Zhehao , Zheng Haoquan
Published: February 2023

A bimetallic 3D interconnected metal–organic framework (MOF) with 2D morphology has been used as a precursor to generate derivatives for electrocatalysis.
Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages
Authors: Patriarca Marina , Barlow Nicola , Cross Alan , Hill Sarah , Robson Anna , Tyson Julian
Published: February 2023

This review discusses developments in elemental mass spectrometry, atomic absorption, emission and fluorescence, XRF and LIBS, as applied to the analysis of specimens of clinical interest, foods and beverages. Sample preparation procedures and quality assurance are also included.
Eco-friendly fabrication of coco coir composites for hydroponic cultivation: a green chemistry approach
Authors: Both Avinash Kumar , Choudhry Deepa , Cheung Chin Li
Published: February 2023

A pectin-based one-pot aqueous approach was reported to valorize coco coir into multifunctional biocomposites. These biocomposites were demonstrated to be effective hydroponic growth media.
Correction: Single-pot template-free synthesis of a glycerol-derived C–Si–Zr mesoporous composite catalyst for fuel additive production
Authors: Kumar Saurabh , Viswanadham Nagabhatla , Saxena Sandeep K. , Selvamani Arumugam , Diwakar Jitendra , Al-Muhtaseb Ala’a H.
Published: February 2023

Correction for ‘Single-pot template-free synthesis of a glycerol-derived C–Si–Zr mesoporous composite catalyst for fuel additive production’ by Saurabh Kumar et al., New J. Chem., 2020, 44, 8254–8263, https://doi.org/10.1039/D0NJ00523A.
Hybrid 3D printing for highly efficient nanoparticle micropatterning
Authors: Jambhulkar Sayli , Ravichandran Dharneedar , Sundaravadivelan Barath , Song Kenan
Published: February 2023

Anisotropic micropatterns generated on a template surface are fabricated via fused deposition modeling (FDM) 3D printing due to the staircase mechanism which acts as a patterning/assembly site for MXene nanoparticles deposited via microfluidics.
From tensegrity to human organs-on-chips: implications for mechanobiology and mechanotherapeutics
Authors: Ingber Donald E.
Published: February 2023

The field of mechanobiology, which focuses on the key role that physical forces play in control of biological systems, has grown enormously over the past few decades. Here, I provide a brief personal perspective on the development of the tensegrity theory that contributed to the emergence of the mechanobiology field, the key role that crossing disciplines has played in its development, and how it has matured over time. I also describe how pursuing questions relating to mechanochemical transduction and mechanoregulation can lead to the creation of novel technologies and open paths for development of new therapeutic strategies for a broad range of diseases and disorders.
Mitochondrial dynamics in macrophages: divide to conquer or unite to survive?
Authors: Afroz Syeda Farhana , Raven Karoline D. , Lawrence Grace M.E.P. , Kapetanovic Ronan , Schroder Kate , Sweet Matthew J.
Published: February 2023

Mitochondria have long been appreciated as the metabolic hub of cells. Emerging evidence also posits these organelles as hubs for innate immune signalling and activation, particularly in macrophages. Macrophages are front-line cellular defenders against endogenous and exogenous threats in mammals. These cells use an array of receptors and downstream signalling molecules to respond to a diverse range of stimuli, with mitochondrial biology implicated in many of these responses. Mitochondria have the capacity to both divide through mitochondrial fission and coalesce through mitochondrial fusion. Mitochondrial dynamics, the balance between fission and fusion, regulate many cellular functions, including innate immune pathways in macrophages. In these cells, mitochondrial fission has primarily been associated with pro-inflammatory responses and metabolic adaptation, so can be considered as a combative strategy utilised by immune cells. In contrast, mitochondrial fusion has a more protective role in limiting cell death under conditions of nutrient starvation. Hence, fusion can be viewed as a cellular survival strategy. Here we broadly review the role of mitochondria in macrophage functions, with a focus on how regulated mitochondrial dynamics control different functional responses in these cells.
The role of PQBP1 in neural development and function
Authors: Cheng Shanshan , Liu Xian , Yuan Linjuan , Wang Nan , Zhang Zi Chao , Han Junhai
Published: February 2023

Mutations in the polyglutamine tract-binding protein 1 (PQBP1) gene are associated with Renpenning syndrome, which is characterized by microcephaly, intellectual deficiency, short stature, small testes, and distinct facial dysmorphism. Studies using different models have revealed that PQBP1 plays essential roles in neural development and function. In this mini-review, we summarize recent findings relating to the roles of PQBP1 in these processes, including in the regulation of neural progenitor proliferation, neural projection, synaptic growth, neuronal survival, and cognitive function via mRNA transcription and splicing-dependent or -independent processes. The novel findings provide insights into the mechanisms underlying the pathogenesis of Renpenning syndrome and may advance drug discovery and treatment for this condition.
Mitochondrial DNA in cell death and inflammation
Authors: Heilig Rosalie , Lee Jordan , Tait Stephen W.G.
Published: February 2023

Cytosolic DNA is recognized by the innate immune system as a potential threat. During apoptotic cell death, mitochondrial DNA (mtDNA) release activates the DNA sensor cyclic GMP–AMP synthase (cGAS) to promote a pro-inflammatory type I interferon response. Inflammation following mtDNA release during apoptotic cell death can be exploited to engage anti-tumor immunity and represents a potential avenue for cancer therapy. Additionally, various studies have described leakage of mtDNA, independent of cell death, with different underlying cues such as pathogenic infections, changes in mtDNA packaging, mtDNA stress or reduced mitochondrial clearance. The interferon response in these scenarios can be beneficial but also potentially disadvantageous, as suggested by a variety of disease phenotypes. In this review, we discuss mechanisms underlying mtDNA release governed by cell death pathways and summarize release mechanisms independent of cell death. We further highlight the similarities and differences in mtDNA release pathways, outlining gaps in our knowledge and questions for further research. Together, a deeper understanding of how and when mtDNA is released may enable the development of drugs to specifically target or inhibit mtDNA release in different disease settings.
Modelling individual head‐related transfer function (HRTF) based on anthropometric parameters and generic HRTF amplitudes
Authors: Zhang Rui , Meng Ruijie , Sang Jinqiu , Hu Yi , Li Xiaodong , Zheng Chengshi
Published: February 2023

The head‐related transfer function (HRTF) plays a vital role in immersive virtual reality and augmented reality technologies, especially in spatial audio synthesis for binaural reproduction. This article proposes a deep learning method with generic HRTF amplitudes and anthropometric parameters as input features for individual HRTF generation. By designing fully convolutional neural networks, the key anthropometric parameters and the generic HRTF amplitudes were used to predict each individual HRTF amplitude spectrum in the full‐space directions, and the interaural time delay (ITD) was predicted by the transformer module. In the amplitude prediction model, the attention mechanism was adopted to better capture the relationship of HRTF amplitude spectra at two distinctive directions with large angle differences in space. Finally, with the minimum phase model, the predicted amplitude spectrum and ITDs were used to obtain a set of individual head‐related impulse responses. Besides the separate training of the HRTF amplitude and ITD generation models, their joint training was also considered and evaluated. The root‐mean‐square error and the log‐spectral distortion were selected as objective measurement metrics to evaluate the performance. Subjective experiments further showed that the auditory source localisation performance of the proposed method was better than other methods in most cases.
Complexity‐reduced maximum‐likelihood hybrid detection for MIMO systems
Authors: Chang Ming‐Xian , Su Szu‐Lin
Published: February 2023

For wireless communications, the multiple‐input multiple‐output (MIMO) system efficiently makes use of the spectrum and enhances the transmission throughput. In this work, the maximum‐likelihood (ML) detection for the MIMO system is studied, and two ML detection algorithms are first considered for the MIMO system, including the sphere decoding (SD) algorithm and an algorithm based on differential metrics (DMs). Each of the two algorithms has its advantages and disadvantages. The two algorithms are first modified such that they are based on the same signal model. Then, a new ML detection algorithm is proposed for the MIMO system based on the hybrid operation of the two modified algorithms on the tree search process, in which both the branch‐and‐bound principle and indicative functions are applied to remove unnecessary searches. The proposed algorithm can attain the ML detection with lower average complexity over low and high ranges of signal‐to‐noise ratio (SNR), as the authors verify by simulations. The proposed ML detection can also generate soft output, and anti‐phase sequences are exploited to further reduce the complexity.
Maximizing the network outage rate for fast fluid antenna multiple access systems
Authors: Wong Kai‐Kit , Tong Kin‐Fai , Chen Yu , Zhang Yangyang
Published: February 2023

Using reconfigurable fluid antennas, it is possible to have a software‐controlled position‐tuneable antenna to realize spatial diversity and multiplexing gains that are previously only possible using multiple antennas. Recent results illustrated that fast fluid antenna multiple access (f‐FAMA) which always tunes the antenna to the position for maximum signal‐to‐interference ratio (SIR) on a symbol‐by‐symbol basis, could support hundreds of users on the same radio channel, all by a single fluid antenna at each user without complex coordination and optimization. The network outage rate, nevertheless, depends on the SIR threshold chosen for each user. Motivated by this, this paper adopts a first‐order approximation to obtain the outage probability expression from which a closed‐form solution is derived for optimizing the SIR threshold in maximizing the network outage rate. Moreover, a closed‐form expression is provided to estimate the number of users in the f‐FAMA network in which the outage rate begins to plateau. Numerical results show that the proposed SIR threshold achieves near‐maximal outage rate performance.
Decentralized energy management system for smart microgrids using reinforcement learning
Authors: Darshi Razieh , Shamaghdari Saeed , Jalali Aliakbar , Arasteh Hamidreza
Published: February 2023

This paper presents a novel fully decentralized and intelligent energy management system (EMS) for a smart microgrid based on reinforcement learning (RL) strategy. The purpose of the proposed EMS is to maximize the benefit of all microgrid entities comprising customers and distributed energy resources (DERs). Due to unpredictable features of renewable energy sources and variability of consumers’ demands, designing the microgrid EMS is a complicated task. To overcome this issue, the multi‐agent hour‐ahead energy management problem is modelled as a finite Markov decision process. The microgrid entities are considered as intelligent agents. The optimal policy of agents is obtained through a newly developed framework of the model‐free Q‐learning algorithm to maximize the benefit of all renewable and non‐renewable energy resources and battery energy storage system. The degradation model of the battery is considered to reduce the number of battery replacements. To ensure customers’ comfort, customers’ expenses are decreased without demand curtailment via introducing two types of load shifting techniques. The microgrid operation is analysed under four scenarios comprising no‐learning, generator‐learning, customer‐learning, and whole‐learning. the performance of the proposed algorithm is compared to the Monte Carlo method and simulation results on the real power‐grid dataset show the superiority of the algorithm.
Comprehensive analysis and design of a switched‐inductor type low inductance‐requirement DC‐DC buck‐boost converter for low power applications
Authors: Hamood‐Ur‐Rehman  , Ahmed Nisar , Sher Hadeed Ahmed , Al‐Durra Ahmed , Hasanien Hany M
Published: February 2023

This paper aims to comprehensively analyze, critically discuss, and provide a step‐by‐step design guideline for a previously proposed Modified Switched‐Inductor type Buck‐Boost (MSIBB) converter which is based on a boost converter. The MSIBB converter is originally based on switched‐inductor phenomena whereby two inductors are switched in a proper sequence to ensure appreciable buck as well as boost characteristics. Appreciable buck and boost characteristics are desirable specifically in low power applications. In regulated low power applications, DC‐DC switching power converters undergo frequent mode‐shift from buck to boost, and vice versa. At the overlap between input/output voltage, the converters efficiency does not suffer significantly, but the wide input‐voltage operating area compels the regulated converters to operate at extreme values of the duty cycle, that is, close to 0 and 1, which causes lower efficiency. A high‐efficiency switching converter is required specifically for low‐power applications that can ensure voltage step‐up and step‐down without resorting to operating at extreme values of the duty‐cycle. In this perspective, switched‐inductors based converter, termed as MSIBB converter, was previously proposed. The MSIBB converter exhibits appreciable voltage‐gain, and experiences lesser current/voltage stress on the semiconductor components. In particular, it has comparable Maximum Switch Stress Factor that generally translates to alleviated switch conduction and switching losses. Besides, the inductors minimum peak stored energy is comparatively lower, reflecting reduced physical size of the inductors as well as reduced onboard losses, and therefore better caters to low power applications. Detailed analysis of the converter and step‐by‐step approach for design example, and comparative analysis are carried out, besides providing some experimental results from the previously proposed converter.
Tracking the spectral properties of ESO 511-G030 across different epochs
Authors: Middei R. , Petrucci P.-O. , Bianchi S. , Ursini F. , Matzeu G. A. , Vagnetti F. , Tortosa A. , Marinucci A. , Matt G. , Piconcelli E. , De Rosa A. , De Marco B. , Reeves J. , Perri M. , Guainazzi M. , Cappi M. , Done C.
Published: February 2023

The Type 1 active galactic nucleus (AGN) ESO 511-G030, a formerly bright and soft excess dominated source, was observed in 2019 in the context of a multi-wavelength monitoring campaign. In the new exposures, the source was found to be in a flux state approximately ten times lower than archival exposures and without any trace of the soft excess. Interestingly, the X-ray weakening observed in the 2019 data corresponds to a comparable fading of the UV flux, suggesting a strong link between these two components. The UV-X-ray spectral energy distribution (SED) of ESO 511-G030 shows remarkable variability. We tested both phenomenological and physically motivated models on the data, finding that the overall emission spectrum of ESO 511-G030 in this extremely low flux state is due to the superposition of a power-law-like continuum (Γ ∼ 1.7) and two reflection components emerging from hot and cold matter. Both the primary X-ray continuum and relativistic reflection are produced in the inner regions close to the supermassive black hole. The prominent variability of ESO 511-G030 and the lack of a soft excess can be explained by the dramatic change in the observed accretion rate, which dropped from an L/LEdd of 2% in 2007 to one of 0.2% in 2019. The X-ray photon index also became harder during the low flux observations from 2019, perhaps as a result of a photon starved X-ray corona.
Microlensing of the broad emission line region in the lensed quasar J1004+4112
Authors: Hutsemékers Damien , Sluse Dominique , Savić Đorđe , Richards Gordon T.
Published: February 2023

J1004+4112 is a lensed quasar for which the first broad emission line profile deformations due to microlensing were identified. Detailed interpretations of these features have nevertheless remained controversial. Based on 15 spectra obtained from 2003 to 2018, in this work, we revisit the microlensing effect that distorts the C IV broad emission line profile in J1004+4112. We take advantage of recent measurements of the image macro-magnification ratios, along with the fact that at one epoch, image B was not microlensed, thus constituting a reference spectrum to unambiguously characterize the microlensing effect observed in image A. After disentangling the microlensing in images A and B, we show that the microlensing-induced line profile distortions in image A, although variable, are remarkably similar over a period of 15 years. We find they are characterized by a strong magnification of the blue part of the line profile, a strong demagnification of the red part of the line profile, and a small-to-negligible demagnification of the line core. We used the microlensing effect, characterized by either the full magnification profile of the C IV emission line or a set of four integrated indices, to constrain the broad emission-line region (BLR) size, geometry, and kinematics. For this purpose, we modeled the deformation of the emission lines considering three simple, representative BLR models: a Keplerian disk, an equatorial wind, and a biconical polar wind, with various inclinations with respect to the line of sight. We find that the observed magnification profile of the C IV emission line in J1004+4112 can be reproduced with the simple BLR models we considered, without the need for more complex BLR features. The magnification appears dominated by the position of the BLR with respect to the caustic network – and not by the velocity-dependent size of the BLR. The favored models for the C IV BLR are either the Keplerian disk or the equatorial wind, depending on the orientation of the BLR axis with respect to the caustic network. We also find that the polar wind model can be discarded. We measured the C IV BLR half-light radius as r1/2=2.8−1.7+2.0 light-days. This value is smaller than the BLR radius expected from the radius-luminosity relation derived from reverberation mapping, but it is still in reasonable agreement given the large uncertainties.
Radiation pressure by electron cyclotron waves on density fluctuations
Authors: Ram Abhay , Hizanidis Kyriakos
Published: February 2023

The presence of turbulence in the form of large density fluctuations and coherent filamentary structures in the edge region of fusion plasmas has been well documented. Radio frequency waves, launched from structures near the wall of a tokamak, have to propagate through this turbulent plasma before reaching the core. These density fluctuations can reflect, refract, and diffract the electromagnetic waves, thereby modifying the flow of energy and momentum to the core plasma. Conversely, the radiation pressure of the radio frequency waves can modify the turbulence, whether it is in the edge region or in the core. This article examines some consequences of the radiation force induced by electron cyclotron waves in plasmas. The effect of waves on two different representations of density fluctuations are studied. In the first representation, suitable for both edge and core plasmas, it is assumed that a planar interface separates two different density regimes. The physics basis for the radiation force on an interface separating two different scalar dielectric media was first elucidated by Poynting in 1905 [J. H. Poynting, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science9, 393-406 (1905)]. Poynting’s results are explained within the context of Snell’s law and Fresnel equations, and, subsequently, extended to magnetized plasmas. The analysis shows that electron cyclotron waves lead to peaking of the density profile – the interface is pushed towards the region of higher density. The planar interface approximation is the basis of Kirchhoff theory [P. Beckmann and A. Spizzichino,The Scattering of Electromagnetic Waves from Rough Surfaces(Artech, Massachusetts, 1987) Chapter 3] used to study wave scattering by turbulent media. In the second representation, appropriate for coherent structures in edge plasmas, the radiation force on a cylindrical filament embedded in a background plasma is determined using the Maxwell stress tensor. A detailed study reveals that the radiation force has a different effect on filaments – those with densities higher than the background density are pulled in towards the source launching the waves, while the lower density filaments are pushed away. The reaction on a filament is large enough to be observed experimentally.
Electron Bernstein Wave (EBW) current drive profiles and efficiency for STEP
Authors: Wilson Thomas , Freethy Simon , Henderson Mark , Köhn-Seeman Alf , Konoplev Ivan , Saarelma Samuli , Speirs David , Vann Roddy ,   the STEP team
Published: February 2023

GENRAY and CQL3D were used to estimate the Electron Bernstein Wave (EBW) current drive profiles and normalised current drive efficiency ζCD (6) for several STEP reactor concepts with varying temperature, density, geometry and magnetic field. ζCD > 1.0 was readily found for ρ = 0.65 − 0.9 while ζCD > 0.5 was found for ρ ≥ 0.5. Okhawa is found to be the most efficient current drive mechanism due to the high trapped fraction in STEP. Optimal current drive was found for 2nd harmonic absorption for ρ ≤ 0.8 due to the higher ν⊥ at the wave-particle resonance. 1st harmonic absorption is required for ρ > 0.8 as there is no access to the 2nd harmonic at the launch frequencies examined. Rays with negative starting N∥ were found to penetrate furthest. Due to the high electron temperature in STEP the relativistic downshift of the harmonic becomes comparable to the Doppler shift, increasing access to the 2nd harmonic.
Development of ECRH-based methods for assisted discharge burn-through: Experiment and simulation
Authors: Ricci D. , Stober J. , Dux R. , Figini L. , Wauters T. , Lerche E. , Granucci G. ,   the ASDEX Upgrade Team,   Eurofusion WPTE Team
Published: February 2023

Electron Cyclotron (EC) waves will be routinely used in future reactors not only for plasma heating and/or non-inductive current drive during the flat top but also to assist the plasma start-up phase in large tokamaks with superconductive coils. In ITER, for example, EC start-up is foreseen since first plasma operation. To limit the level of stray radiation, ECRH can be used after ohmic breakdown, as a robust solution to successfully sustain the plasma burn-through in the presence of pre-filling gas and impurity influx from the wall.

On ASDEX Upgrade (AUG), a series of dedicated experiments have been performed using EC heating (X2) with a controlled Ne impurity injection in the prefill phase, to mimic non-favourable burn-through conditions such as would be expected in a discharge following a disruption event. The time for EC heating onset has been optimised to assist the early burn-through and a scan of the Ne concentration has been performed to find the threshold for successful burn-through conditions for two ECH power levels (0.7 and 1.4 MW). The toroidal magnetic field flexibility has been also documented, with the cold resonance position being shifted up to 13% in major radius to match the ITER condition. These experiments showed that optimised settings of ECH power (onset and duration of the pulse) have a key role in making feasible the early Ne burn-through (with Ne concentration up to 14% and EC power of 1.4 MW). Successful pulses will be extended to study stationarity and clean up properties.

For an efficient and robust use of such a technique, it is essential to develop appropriate models capable of describing present experiments and of extrapolating (or predicting) to future scenarios. In this work, the predictive 0D model for the burn-though phase BKD0 [1] has been used to reproduce experimental results and estimate the power required for a successful burn-through as a function of the impurity concentration, finding that ECH power of 1.4 MW is required to sustain burn-through with more than 20% of Ne. The scalability of the model has been also tested on TCV [2] and its implication for ITER will be discussed.
Electron cyclotron heating assisted start-up experiments in J-TEXT
Authors: Zhang Junli , de Vries Peter C , Nagasaki Kazunobu , Xia Donghui , Jiang Wei , Yang Zhoujun , Cheng Zhifeng , Xu Xin , Wang Zhijiang , Wang Nengchao , Gao Li , Ding Yonghua , Chen Zhipeng , Chen Zhongyong , Pan Yuan ,   J-TEXT team
Published: February 2023

Electron cyclotron heating (ECH) breakdown and burn-through assist has been adopted to make the ITER start-up, which uses a low toroidal electric field of about 0.3 V/m, more robust. Related studies have been carried out on many fusion machines such as DIII-D, JT-60U, Tore Supra and FTU. However, the required ECH power to ensure an effective breakdown assist at ITER is not yet clear. Experiment was also performed in J-TEXT to determine the minimum ECH power requirements to assist breakdown and develop a better physics description of the process. The breakdown loop voltage for a successful shot was reduced from 34 to 3.7 V (corresponding to 0.56 V/m) by 300 kW X2-mode ECH power. The critical ECH power to assist the successful formation of a tokamak discharge is about 200kW, and below this value, ionization caused by ECH power is observed, however, the tokamak discharge start-up does not succeed. The effect of different loop voltages and ECH pulse-width on start-up was also studied. As injecting ECH power at a proper time, low ECH power can achieve a similar pre-ionization result as the case with high power. Extremely low breakdown voltage leads to a higher toroidal field later when putting a capacity to continue discharging in J-TEXT. The earlier shutdown of ECH power caused a failed discharge.
ECRH experiments on Tokamaks SST-1 & Aditya-U and ECRH upgradation plan for SST-1
Authors: Shukla Braj Kishore , Patel Jatin , Patel Harshida , Purohit Dharmesh , Mistry Hardik , Parmar K.G. ,   SST-1 Team,   ADITYA-U Team
Published: February 2023

A 42GHz-500kW ECRH system [1-6] is used to carry out various experiments related to plasma breakdown and ECR heating on tokamaks SST-1 and Aditya-U. The system has been upgraded with new anode modulator power supply to launch two ECRH pulses to carry out breakdown and heating simultaneously. In SST-1, ECRH system is used routinely for plasma breakdown at fundamental harmonic, approximately 150kW power is launched for 70ms to 150ms duration and consistent plasma start-up is achieved in SST-1. In the recent experiments, second EC pulse is also launched at the plasma flat-top to heat the plasma, some heating signatures are seen but more experiments will be carried out to confirm the plasma heating with ECRH. In Aditya-U tokamak, simultaneous plasma breakdown and heating experiments are carried out successfully [2]. In the first pulse around 100kW power in fundamental O-mode is launched for 70ms duration for the breakdown at low-loop voltage and around 150kW ECRH power for 50ms duration is launched in second EC pulse to heat the plasma. In case of Aditya-U, plasma heating is observed clearly as soft X-ray signal increases sharply with ECRH. In AdityaU tokamak, deuterium plasma experiments have been carried out and ECRH launched at the flat-top of deuterium plasma current. In deuterium plasma also ECR heating is observed as soft X-ray signal increases with ECH power. For SST-1, ECRH system is being upgraded with another 82.6GHz system, this system would be used to carry out plasma heating and start-up at second harmonic. The 82.6GHz system is already connected with the SST-1 tokamak, the old 82.6GHz-200kW Gyrotron will be upgraded to 400kW system to carry out effective heating experiments on SST-1 at higher ECRH power. The paper discusses the recent results of ECRH experiments carried out on tokamaks SST-1 & Aditya-U and presents the upgradation plan of EC system for SST-1.
Experiments with reduced single pass absorption at ASDEX Upgrade – instrumentation and applications
Authors: Schubert Martin , Stober Joerg , Herrmann Albrecht , Grigore Eduard , Kasparek Walter , Lechte Carsten , Monaco Francesco , Petzold Bernhard , Plaum Burkhard , Poli Emanuele , Ruset Cristian , Vorbrugg Stefan , Wagner Dietmar ,   ASDEX Upgrade Team
Published: February 2023

Reflecting gratings have been installed in the vacuum vessel of ASDEX Upgrade for all beamlines of the electron cyclotron resonance heating system. Potentially unabsorbed millimetre wave power after the first pass through the plasma is redirected towards the plasma centre. This increases the efficiency of heating schemes with reduced single pass absorption like O-2 or X-3. In order to monitor beam position and power, thermocouples were installed into the gratings. A numerical model was developed to evaluate the beam intensity during short pulses from the thermocouple measurement in a non-stationary environment. An experiment was carried out, where only the X-3 resonance is present in the plasma, and the millimetre wave beam shine-through was measured successfully as a function of the central plasma electron temperature. This allows to deduce the X-3 absorption experimentally. Scanning the launching angles, it seems possible to measure the 2D beam cross section after the first pass through the plasma.
Electron temperature fluctuation measurements with Correlation Electron Cyclotron Emission in L-mode and I-mode plasmas at ASDEX Upgrade
Authors: Bielajew Rachel , Conway Garrard D , Happel Tim , Höfler Klara , Cabrera Pedro A Molina , Plank Ulrike , Rodriguez-Fernandez Pablo , Silvagni Davide , Vanovac Branka , Yoo Christian , White Anne ,   The ASDEX Upgrade Team
Published: February 2023

The Correlation Electron Cyclotron Emission (CECE) diagnostic at ASDEX Upgrade (AUG) is used to investigate the features of outer core and pedestal (ρpol = 0.85-1.0) turbulence across confinement regime transitions. The I-mode confinement regime is a promising operational scenario for future fusion reactors because it features high energy confinement without high particle confinement, but the nature of the edge and pedestal turbulence in I-mode plasmas is still under investigation. The edge Weakly Coherent Mode (WCM) appears in the I-mode pedestal and may play a role in transport. In this work we explore electron temperature (Te) fluctuations in the plasma outer core and pedestal using a 24-channel high radial resolution CECE radiometer. CECE measurements provide turbulence information including the Te fluctuation amplitude, turbulent spectra, and radial localization of turbulent features. With CECE measurements we show that the WCM is localized in the pedestal region in both L-mode and I-mode and is measured in optically thick plasmas with a Te fluctuation amplitude of 2.3%. Broadband drift wave turbulence is measured in the outer core with a Te fluctuation amplitude of <1%. A second CECE system recently installed at AUG allowed for non-standard fluctuation measurements during L-mode and I-mode experiments. The second CECE system was toroidally separated from the primary system, allowing measurements of the long-range toroidal correlation of the WCM indicating its low toroidal mode number. A reflectometer sharing a line of sight with the second CECE system enabled density-temperature cross-phase (αne Te ) measurements. The WCM αne Te changes between L-mode and I-mode as the Te gradient steepens.
Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius
Authors: Vanovac Branka , Stober Jörg , Wolfrum Elisabeth , Willensdorfer Matthias , Gil Luís , Faitsch Michael , Bielajew Rachel , Yoo Christian , Conway Garrard , Denk Severin , McDermott Rachael , White Anne ,   Upgrade Team ASDEX
Published: February 2023

EDA H-mode is an ELM-free regime in which the edge quasi-coherent mode (QCM) replaces the ELMs. The estimated location of the quasi-coherent mode is in a partly optically thin region of steep gradients localized between ρpol = 0.96 -1. Relative fluctuations of radiation temperature between 15 and 80 kHz are about 7% with significant density contribution. In the electron cyclotron emission (ECE) channels with resonances in the plasma core, a mode with the same frequency as the quasi-coherent mode is measured. The peak amplitude of both core and edge modes matches the strongest electron temperature gradient in the core and the edge, respectively. The ECE core and edge signals are out of phase. The radiation transport forward model (ECRad) shows that the refraction explains the phase relation between the edge and the core ECE channels. The phase correlates with the sign of the core Te. The amplitude of the fluctuations in the core decreases with decreasing gradients, which is the trend seen in the experiment. The amplitude ratio of the core and edge fluctuation is a factor of five in the experiment; this ratio remains a factor of a hundred in the modeling.
Investigation ofTemeasurements discrepancies between ECE and Thomson diagnostics in high-performance plasmas in JET
Authors: Fontana M. , Giruzzi G. , Orsitto F. P. , de la Luna E. , Dumont R. , Figini L. , Kos D. , Maslov M. , Schmuck S. , Sozzi C. , Challis C. D. , Frigione D. , Garcia J. , Garzotti L. , Hobirk J. , Kappatou A. , Keeling D. , Lerche E. , Maggi C. , Mailloux J. , Rimini F. , Van Eester D. ,   JET contributors
Published: February 2023

For high-temperature JET and TFTR discharges, electron cyclotron emission (ECE) measurements of central electron temperature were systematically found to be up to 20% higher than those taken with Thomson scattering. In recent high-performance JET discharges, centralTemeasurements, performed with LIDAR Thomson scattering and the X-mode ECE interferometer, have been studied in a large database, including deuterium (DD), and deuterium-tritium plasmas (DT). Discrepancies betweenTemeasurements have been observed outside of the experimental uncertainties. ECE measurements, at highTe, have been found to be higher or lower than those of LIDAR, depending on the specific plasma scenario. In addition, discrepancies between the peaks of the second and third harmonic ranges of the ECE spectrum have been interpreted as evidence for the presence of non-Maxwellian features in the electron distribution function. These comparisons seem to suggest that such features can be found in most of the high-performance scenarios selected in this JET database.
Upgrade of the relative calibration methods and Bayesian inference processing for electron cyclotron emission radiometry
Authors: Yu Xin , Shi Zhongbing , Yang Zengchen , Jiang Min , Chen Wei , Wang Tianbo , Pan Wenan
Published: February 2023

An upgraded local oscillator (LO) hopping calibration method based on a blackbody hot source and a perturbation analysis of the magnetic field difference method are introduced in this work. The blackbody hot source is used to evaluate the difference in the relative coefficients between the two LO hopping frequencies in the same channels. Then the coefficients are obtained by multiplying the LO hopping frequencies coefficients by LO hopping calibration coefficients. In this way, it is more flexible and stable than the in-situ calibration. The magnetic field difference method provides another calibration method to obtain the relative calibration coefficients of the electron cyclotron emission radiometers (ECE). In general, the magnetic field difference method needs two similar shots but with a difference of 2.1% (for HL-2M) in the magnetic field. Meanwhile, there are some errors because of the deviation of detection positions in the same channels between the two shots. For evaluating the calibration errors, the impact of the displacement, Te perturbation of the core region, and magnetic field difference has been discussed. The result shows that a larger magnetic field difference can improve the accuracy of the calibration. In the end, Bayesian inference has been utilized to evaluate the calibration coefficients and get the most probable calibration coefficients along with its the confidence interval.
Microwave current drive for STEP and MAST Upgrade
Authors: Freethy Simon , Figini Lorenzo , Henderson Mark , El-Haroun Hana , Eliason Bengt , Gibson Sam , Kirov Krassimir , Köhn-Seemann Alf , Konoplev Ivan , Saarelma Samuli , Sharma Ridhima , Speirs David , Vann Roddy , Webster Helen , Wilson Thomas ,   the STEP team
Published: February 2023

The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program has recently taken the decision to use exclusively microwave-based heating and current drive (HCD) actuators for its reactor concepts. This is based on a detailed assessment considering all viable HCD concepts, covering the grid to plasma efficiency, physics applications, technology maturity, integration, maintenance, and costs. Of the two microwave techniques: Electron Cyclotron (EC) and Electron Bernstein Wave (EBW), EC was deemed the lowest risk and EBW is retained as a potential path to a more efficient, higher performing device. To assess the ECCD efficiency, the GRAY beam tracing code was employed to perform detailed scans of the launcher position, toroidal and poloidal launch angle, and frequency over the first 3 cyclotron harmonics. For EBW, GENRAY/CQL3D were used to estimate the CD efficiency, demonstrating promising results. To reduce the physics uncertainties in present models for EBW coupling and current drive, MAST Upgrade will install two dual frequency (28, 34.8 GHz), 900kW, 5s gyrotrons from Kyoto Fusioneering, as part of the MAST Upgrade enhancements package. This will be accompanied by a flexible 2D steering launcher system to allow midplane coand counter-CD and above midplane launch for co-direction off-axis CD. Coupling efficiency is quantified by measuring the heating induced by reflected (i.e. non-coupled) power to a plate inserted in the reflected beam path. The experiments will also include EBW driven solenoid-free start-up, increasing power and pulse length by a factor of 10 compared to previous MAST experiments. This presentation will discuss the STEP microwave studies and the MAST Upgrade physics design and capabilities.
MAST Upgrade microwave heating and current drive system – engineering design overview
Authors: Webster Helen , Freethy Simon , Henderson Mark , Allen Joe , Caretta Ottone , Desai Shail , Holden James , Maszczyk Dariusz , Melidis Elias , Meyer Hendrik , Muir Ewan , Munasinghe Asanka , Surendran Santhosh
Published: February 2023

MAST-Upgrade (MAST-U) is undergoing several enhancements to deliver increased performance and functionality. One such enhancement is the design, development, and implementation of an Electron Bernstein Wave (EBW) Heating and Current Drive (HCD) System. The MAST-U EBW System aims to provide experimental data for model validation, and to provide a greater understanding of EBW physics and its capabilities. The MAST-U EBW System provides up to 1.8 MW of microwave power into the plasma, through a system comprising: high voltage power supplies; two gyrotrons; evacuated transmission lines; a steerable in-vessel launching system; and associated control and ancillary systems. The gyrotrons from Kyoto Fusioneering have a 0.9 MW output power capability at the dual frequencies of 28GHz and 34.8GHz, allowing start-up and current drive studies to be carried out at their respective optimum frequencies. Additional diagnostics, termed interceptor plates, are proposed to sit in the path of the first reflection. These will measure the reflected power from the plasma, to both act as an interlock if the reflected power is too high, and provide key information on the coupling efficiency.
Status of the ITER ECRH&CD control system development
Authors: Carannante Giuseppe , Cavinato Mario , Cindric Katarina , Ferrari Martino , Ferrò Giuseppe , Cabrita Neto Andre , Sartori Filippo
Published: February 2023

The ITER ECRH&CD system is designed to inject 20 MW of millimetre-wave at 170 GHz into the vacuum vessel. The system is composed of many sub-systems, namely High-Voltage Power Supplies (HVPS), Gyrotrons, Transmission Lines (TL), Ex-vessel Waveguides (EW), Launchers. It is the role of the EC Plant Controller (ECPC) to integrate all the Sub-system Control Units (SCU), to prepare the system for operation and to execute the real-time requests coming from the plasma control system. Plant level protections are also implemented by the ECPC, in charge of ensuring the safe operation of the plant, while optimizing the power availability. While control and protection functions are always pushed to the lower possible controller able to implement them, the operational requirements and flexibility of the system make it impossible to fully segregate many functions, since each gyrotron is connected to at least two different launching mirrors. To simplify the SCUs’ development and to respect the responsibility boundaries imposed by the procurement strategy, all the functions involving more than one sub-system are implemented in the ECPC, which exposes a single operational interface towards the ITER Central I&C. The status of the control system development is presented in this work.