bluuebunny/crossref_metadata_2025 huggingface dataset:
Compact scanning retarding potential analyzer
Authors: Goebel Dan M. , Becatti Giulia
Published: January 2021

A miniature scanning electrostatic energy analyzer has been developed for measurements of the ion energy distribution in low-pressure plasma discharges. The retarding potential analyzer utilizes four grids to reject the incident electron flux and discriminate the ion energy. It features a compact size of 5-mm diameter and 2.5-mm thickness and uses a simple configuration to mount the grids and provide voltage isolation using high temperature ceramic cement that avoids complicated grid alignment or MEMS fabrication techniques. Mounting on a fast-scanning two-axis probe drive eliminates overheating of the ceramics and subsequent current leakage, which permits insertion into challenging locations and provides profiles of the ion energy in the plasma discharge. Guidelines for the analyzer design for high density operation are discussed, and the performance of the analyzer is shown for measurements in a hollow cathode plume in xenon plasmas.
Enhancing discharging performance of a phase change thermal storage unit with a fractal space-filling matrix
Authors: Li Jie , Zheng Yi , Liu Xiangdong
Published: January 2021

The phase change thermal storage (PCTS) technique is essential for renewable energy utilization. To strengthen the heat-discharge performance, an innovative PCTS unit with a fractal space-filling matrix is proposed. Based on the established solidification model, the solidification interface transformation and temperature field evolution of the innovative PCTS unit are numerically analyzed and compared with those of conventional units. Moreover, the roles of the structural parameters of PCTS units are investigated in terms of the resulting solidification behavior, and the metal matrix is optimized in terms of the solidification duration. The results show that the fractal space-filling matrix effectively improves the heat-discharge performance. Compared to conventional PCTS units, the proposed PCTS unit with a fractal space-filling matrix produces a more uniform temperature field and enhances the solidification rate by approximately 40%. Regarding the trade-off between cost and performance, a fractal level of two is suggested to maximize the heat-discharge enhancement and minimize the manufacturing cost. To minimize the solidification duration, the optimal length and thickness ratios of the fractal space-filling matrix are found to be 0.4 and 0.5, respectively, for practical engineering applications.
The role of entrance functionalization in carbon nanotube-based nanofluidic systems: An intrinsic challenge
Authors: Tao Ran , Gao Xiang , Lin Dewu , Chen Yixuan , Jin Yakang , Chen Xibing , Yao Shuhuai , Huang Pingbo , Zhang Jin , Li Zhigang
Published: January 2021

In this work, experiments, molecular dynamics (MD) simulations, and theoretical analysis are conducted to study ion transport in thin carbon nanotubes (CNTs). Diverse nonlinear relationships between the ionic conductance (G) and the ion concentration (C) are observed. MD simulations show that the distinct G–C dependences are caused by the functionalization of the CNT entrance, which affects the energy barrier for ion transport and changes the ionic conductance. The various G–C relationships are also predicted using the electrokinetic theory by considering the potential generated by the functional groups at the CNT entrance. Practically, the number of functional groups at the CNT entrance is influenced by several factors, including both intrinsic and external effects, which make it difficult to regulate the ionic conductance and pose a challenge to CNT-based nanofluidic systems in practical applications.
Conditioning nano-LEDs in arrays by laser-micro-annealing: The key to their performance improvement
Authors: Mikulics M. , Kordoš P. , Gregušová D. , Sofer Z. , Winden A. , Trellenkamp St. , Moers J. , Mayer J. , Hardtdegen H.
Published: January 2021

A local so-called laser-micro-annealing (LMA) conditioning technology, which is suitable for the fabrication of a large range of hybrid nano-optoelectronic devices, was applied to III-nitride-based nano-light emitting diodes (LEDs). The LEDs with a diameter of ∼100 nm were fabricated in large area arrays and designed for hybrid optoelectronic applications. The LMA process was developed for the precise local conditioning of LED nano-structures. Photoluminescence measurements reveal the enhancement of nano-LED properties, which is in very good agreement with a simple model introduced based on the reduction of the defect layer depth by the LMA process. The experimental data confirm the reduction of the defect layer depth from ∼17 nm to ∼5 nm determined. In consequence, an increase in work currents up to 40 nA at 5 V bias after the LMA procedure as well as high electroluminescence (EL) and output optical power up to 150 nW in the ∼440–445 nm emission wavelength range corresponding to ∼75% wall-plug efficiency were achieved. Additionally, the LEDs' electroluminescence intensities reach the desired values by conditioning the contact/annealed regions of individual LEDs accordingly. Furthermore, the LMA process affects the long-term stability of the electroluminescence (EL) intensity of single nano-LED devices. A study of the EL during 5000 h in the continuous wave operation testing mode revealed a moderate ∼15% decrease in the intensity in comparison to ∼50% for their non-LMA counterparts. Finally, Raman measurements indicate that the “work” temperature for nano-LED conditioned structures decreases.
Exploring the next step in micro-solvation of CO in water: Infrared spectra and structural calculations of (H2O)4–CO and (D2O)4–CO
Authors: Barclay A. J. , Pietropolli Charmet A. , McKellar A. R. W. , Moazzen-Ahmadi N.
Published: January 2021

We extend studies of micro-solvation of carbon monoxide by a combination of high-resolution IR spectroscopy and ab initio calculations. Spectra of the (H2O)4–CO and (D2O)4–CO pentamers are observed in the C–O stretch fundamental region (≈2150 cm−1). The H2O containing spectrum is broadened by predissociation, but that of D2O is sharp, enabling detailed analysis that gives a precise band origin and rotational parameters. Ab initio calculations are employed to confirm the assignment to (water)4–CO and to determine the structure in which the geometry of the (water)4 fragment is a cyclic ring very similar to the isolated water tetramer. The CO fragment is located “above” the ring plane, with a partial hydrogen bond between the C atom and one of the “free” protons (deuterons) of the water tetramer. Together with the previous results on D2O–CO, (D2O)2–CO, and (D2O)3–CO, this represents a probe of the four initial steps in the solvation of carbon monoxide at a high resolution.
Bandpass sorting of heterogeneous cells using a single surface acoustic wave transducer pair
Authors: Simon Gergely , Busch Caroline , Andrade Marco A. B. , Reboud Julien , Cooper Jonathan M. , Desmulliez Marc P. Y. , Riehle Mathis O. , Bernassau Anne L.
Published: January 2021

Separation and sorting of biological entities (viruses, bacteria, and cells) is a critical step in any microfluidic lab-on-a-chip device. Acoustofluidics platforms have demonstrated their ability to use physical characteristics of cells to perform label-free separation. Bandpass-type sorting methods of medium-sized entities from a mixture have been presented using acoustic techniques; however, they require multiple transducers, lack support for various target populations, can be sensitive to flow variations, or have not been verified for continuous flow sorting of biological cells. To our knowledge, this paper presents the first acoustic bandpass method that overcomes all these limitations and presents an inherently reconfigurable technique with a single transducer pair for stable continuous flow sorting of blood cells. The sorting method is first demonstrated for polystyrene particles of sizes 6, 10, and 14.5 μm in diameter with measured purity and efficiency coefficients above 75 ± 6% and 85 ± 9%, respectively. The sorting strategy was further validated in the separation of red blood cells from white blood cells and 1 μm polystyrene particles with 78 ± 8% efficiency and 74 ± 6% purity, respectively, at a flow rate of at least 1 μl/min, enabling to process finger prick blood samples within minutes.
Size- and temperature-dependent Young's modulus of SiC nanowires determined by a laser-Doppler vibration measurement
Authors: Yibibulla Tursunay , Jiang Yijun , Wang Shiliang , Huang Han
Published: January 2021

Young's modulus of Fe-catalyzed silicon carbide (SiC) nanowires was measured in the temperature range of 300–575 K by the use of a laser Doppler vibrometer. The nanowires have a face-centered cubic structure grown along the [111] direction and exhibit different cross-sectional geometries, including circle, rectangle, hexagon, ellipse, trapezoid, and triangle. When the effective diameters of the nanowires decrease from 200 to 55 nm, their room-temperature Young's modulus decreases from ∼550 GPa (the bulk value) to ∼460 GPa, i.e., a reduction of ∼16%, and their temperature coefficient of Young's modulus varies from −47.4 ± 1.7 ppm/K (the bulk value) to −78.1 ± 5.9 ppm/K, i.e., a change of ∼65%. The size and temperature dependency of the modulus would greatly benefit the design and fabrication of high-temperature mechanical sensors based on SiC nanostructures.
Nurse practitioner locums: a plausible solution for augmenting health care access for rural communities
Authors: Jennings Natasha , Lowe Grainne , Tori Kathleen
Published: January 2021

With 2020 being designated the Year of the Nurse and Midwife, it is opportune to acknowledge and recognise the role that nurses undertake in primary care environments. Nurses and midwives play a pivotal role in the delivery of high-quality health care, particularly in geographically challenged areas of Australia, where they may be the only provider of care within their communities. Rural and remote health services require strategic planning to develop and implement solutions responsive to the challenges of rural and remote communities. Maintenance of health services in rural and remote areas is a challenge, crucial to the equity of health outcomes for these communities. Many small communities rely on visiting medical officers to provide the on-call care to facility services, including emergency departments, urgent care centres, acute wards and aged care facilities. It is increasingly difficult to maintain the current rural workforce models, particularly the provision of after-hours ‘on-call’ care necessary in these communities. An alternative model of health care service delivery staffed by nurse practitioners (NP) is one proposed solution. NPs are educated, skilled and proven in their ability to provide an after-hours or on-call service to meet the expectations of rural and remote communities. Achievement of high-quality health care that is cost-efficient, safe and demonstrates improved patient outcomes has been reported in NP-led health care delivery impact evaluations. The value of an NP locum service model is the provision of a transparent, reliable service delivering consistent, equitable and efficient health care to rural and remote communities.
Arabidopsiscell wall composition determines disease resistance specificity and fitness
Authors: Molina Antonio , Miedes Eva , Bacete Laura , Rodríguez Tinguaro , Mélida Hugo , Denancé Nicolas , Sánchez-Vallet Andrea , Rivière Marie-Pierre , López Gemma , Freydier Amandine , Barlet Xavier , Pattathil Sivakumar , Hahn Michael , Goffner Deborah
Published: January 2021

Significance

Plant cells are surrounded by an extracellular matrix known as the cell wall. We have analyzed the contribution of theArabidopsiscell wall to disease resistance to pathogens with different parasitic styles. Here, we demonstrate that plant cell walls are determinants of immune responses since modification of their composition in a set ofArabidopsiscell wall mutants has an impact on their disease resistance and fitness phenotypes. In these genotypes, we identified specific correlations between the amounts of specific wall carbohydrate epitopes and disease resistance/fitness phenotypes through mathematical analyses. These data support the relevant and specific function of plant cell wall composition in plant immune responses and provide the basis for using wall traits in crop breeding programs.
Focus enclitics in Bodo
Authors: Boro Krishna
Published: January 2021

This paper describes a set of five focus enclitics in Bodo, a Tibeto-Burman language spoken in Assam, India. The focus enclitics are phonologically bound morphemes which are attached to a phrase-level constituent of a sentence, such as the verb, its arguments, or its adjuncts. They all trigger existential presuppositions and express various kinds of semantic and pragmatic relations between the asserted proposition and presuppositions, such as inclusion, exclusion, contrast, concession, and correction. The description of these relations as well as other more context and construction specific functions encoded by the focus enclitics constitutes the core of this paper. This paper also examines the distribution of the focus enclitics and discusses their associated scope and interpretations. Finally, this paper investigates co-occurrence, co-occurrence restrictions, and interpretations of sequences of the enclitics.
Noun-epithets of Dongba and Daba oral traditions
Authors: Xu Duoduo
Published: January 2021

Dongba and Daba chants represent two of the few oral traditions still surviving in the world. In both traditions, the main category of formulaic expressions consists of traditional noun-epithets describing spirits. Dongba and Daba spirits can be classified into five categories, of which the noun-epithets used to describe them share similar features. Another significant percentage of noun-epithets portray figures of animals. Dongba and Daba chants are both chanted in odd-numbered metric patterns in which noun-epithets are adapted to the metric context. Besides the core expression (often a tetra-syllabic compound), several monosyllabic words not affecting the core meaning may be inserted as optional morphemes to modify the number of syllables in the noun-epithet. This study provides a systematic philological analysis of the vast repertoire of Daba and Dongba noun-epithets. Comparative mythology and comparative linguistics combine to present a comprehensive description of the stylistic features of Daba and Dongba noun-epithets.
Climate change–food security nexus in Burkina Faso
Authors: Hamid El Bilali
Published: January 2021

Climate change is expected to have far-reaching impacts on food security. Such impacts are likely to be higher in developing countries. This paper analyses the state of research on the nexus between climate change and food security in Burkina Faso. In particular, it sheds light on whether and how the scholarly literature addresses the impacts of climate change on the four dimensions of food security (i.e. food availability, food access, food utilisation and stability). It also explores the synergies and trade-offs between climate change mitigation/adaptation and food security. A search performed in April 2020 on the Web of Science yielded 243 records and 62 of them, which resulted eligible, were included in the systematic review. The literature shows that climate change will affect all the four dimensions of food security. However, most of the analysed literature addresses its effects on food availability. Indeed, it focuses on impacts on crop yields and climate suitability for crops (e.g. maize, millet, sorghum). Moreover, most of the impacts on the remaining food security dimensions stem from the negative effects on food production and supply (cf. food availability). The review also shows that, on the one hand, climate change mitigation can undermine food security and, on the other hand, agriculture intensification and some adaptation strategies, which aim to enhance food security, might increase emissions from agriculture. The dual climate change—food security relationship calls for integrated policies that address trade-offs and optimise co-benefits between ‘climate action’ and ‘zero hunger’ in Burkina Faso.
At-home meditation for tinnitus management
Authors: Fitzgerald Brendan P. , Stocking Christina , Ralli Massimo , Sheppard Adam
Published: January 2021

Objective

Chronic subjective tinnitus can be severely debilitating. Recently, structured meditation programs have shown to reduce the negative consequences of tinnitus. However, it remains unclear if the structured nature of such meditation programs is required to effectively manage tinnitus. This study investigated if at-home meditation, guided with a free smart device application, could serve as an alternative to structured, in-person programs.

Methods

We monitored self-reported tinnitus severity and other comorbid disorders in 15 participants reporting bothersome tinnitus over an 8-week period. Subjects were asked to meditate for 30 m/d, 5d/w, for 8 consecutive weeks. Questionnaires were administered at baseline, and after 3 weeks, and 8 weeks of at-home meditation.

Results

Outcomes indicated at-home meditation practice yielded significant reductions in THI scores after 3 weeks, and significant reductions in THI and TFI scores after 8 weeks. HADS-D scores were significantly reduced after 8 weeks of at-home meditation, but HADS-A scores showed no significant change throughout the study. MAAS scores were significantly enhanced after 3 weeks of at-home meditation practice, and further enhanced at the 8-week time point.

Conclusion

At-home meditation could serve as an acceptable alternative to in-person meditation programs to manage tinnitus. However, our data also highlight caveats that warrant further investigation.
High-fidelity reconstitution of stress granules and nucleoli in mammalian cellular lysate
Authors: Freibaum Brian D. , Messing James , Yang Peiguo , Kim Hong Joo , Taylor J. Paul
Published: January 2021

Liquid–liquid phase separation (LLPS) is a mechanism of intracellular organization that underlies the assembly of a variety of RNP granules. Fundamental biophysical principles governing LLPS during granule assembly have been revealed by simple in vitro systems, but these systems have limitations when studying the biology of complex, multicomponent RNP granules. Visualization of RNP granules in cells has validated key principles revealed by simple in vitro systems, but this approach presents difficulties for interrogating biophysical features of RNP granules and provides limited ability to manipulate protein, nucleic acid, or small molecule concentrations. Here, we introduce a system that builds upon recent insights into the mechanisms underlying RNP granule assembly and permits high-fidelity reconstitution of stress granules and the granular component of nucleoli in mammalian cellular lysate. This system fills the gap between simple in vitro systems and live cells and allows for a variety of studies of membraneless organelles, including the development of therapeutics that modify properties of specific condensates.
Persistent cellular immunity to SARS-CoV-2 infection
Authors: Breton Gaëlle , Mendoza Pilar , Hägglöf Thomas , Oliveira Thiago Y. , Schaefer-Babajew Dennis , Gaebler Christian , Turroja Martina , Hurley Arlene , Caskey Marina , Nussenzweig Michel C.
Published: January 2021

SARS-CoV-2 is responsible for an ongoing pandemic that has affected millions of individuals around the globe. To gain further understanding of the immune response in recovered individuals, we measured T cell responses in paired samples obtained an average of 1.3 and 6.1 mo after infection from 41 individuals. The data indicate that recovered individuals show persistent polyfunctional SARS-CoV-2 antigen–specific memory that could contribute to rapid recall responses. Recovered individuals also show enduring alterations in relative overall numbers of CD4+ and CD8+ memory T cells, including expression of activation/exhaustion markers, and cell division.
Ionic and molecular transport in aqueous solution through 2D and layered nanoporous membranes
Authors: Caglar M , Keyser U F
Published: January 2021

Two-dimensional (2D) materials provide an intriguing means to not only study physical phenomena but also serve as disruptive membranes for ionic selectivity and sensing based applications. Atomic thinness of these materials affords a unique environment in an all-surface material to unlock challenges towards improving desalination, energy harvesting and DNA sensing. This review provides an overview on some common 2D materials used in membrane applications for solving these challenges along with opportunities where 2D materials could add value to existing solutions. Following this, different types of 2D materials and structures are discussed with their relative advantages and disadvantages highlighted. Fabrication and methods of creating pores within 2D membranes are then presented with a focus on altering surface characteristics. Selected works within the field are highlighted and placed into a wider context, comparing their merits and shortfalls. A discussion of state-of-the-art performance for ionic transport, molecular sensing and power generation is then presented. This review concludes with an outlook on emerging methods and discussing exciting future directions.
In situ ambient pressure XPS study of Pt/Cu(111) single-atom alloy in catalytically relevant reaction conditions
Authors: Simonovis Juan Pablo , Hunt Adrian , Waluyo Iradwikanari
Published: January 2021

The presence of multiple reactant gases as well as reaction intermediates in a heterogeneous catalytic reaction results in a complex interaction between different components of the catalyst with each gas, which can alter the surface and chemical state of the catalyst differently than in the presence of an individual gas alone. In this study, we used in situ ambient pressure x-ray photoelectron spectroscopy to study the surface state of Pt/Cu(111) single-atom alloy model system in two catalytically relevant reaction conditions: CO2 hydrogenation and CO oxidation. We found that the activation of CO2 results in the formation of CO, which adsorbs on Pt sites at up to 400 K. In the presence of CO2 and H2, Pt catalyzes the reverse water–gas shift reaction, which produces more CO and further stabilizes surface Pt atoms at 450 K. On the other hand, in CO oxidation condition, the presence of O2 results in the formation of a thick Cu2O layer at higher temperatures, and Pt atoms are no longer detected in the surface and subsurface layers. When O2 is introduced to the sample before CO, the formation of a complete Cu2O layer that covers all Pt atoms occurs immediately at room temperature. However, when CO is introduced at room temperature before O2, the presence of adsorbed CO on Pt sites stabilizes the surface Pt atoms and prevents the formation of a complete Cu2O layer, thus exposing the Pt atoms in ‘holes’ in the Cu2O layer.
An edge-labeling graph neural network method for tool wear condition monitoring using wear image with small samples
Authors: Zhi Gaofeng , He Dedao , Sun Weifang , Zhou Yuqing , Pan Xiaoming , Gao Chen
Published: January 2021

Tool wear condition monitoring (TCM) is of great significance to ensure manufacturing quality in milling processes, and the development of deep learning (DL) in recent years has led to increasing interest in DL-based TCM methods. However, most of these DL-based methods rely on large training samples to achieve good performances, which is expensive. In this paper, a new TCM method based on an edge-labeling graph neural network (EGNN) is proposed for small training datasets. First, the tool wear image is input into a convolution neural network (CNN) to extract features and obtain the features of the training samples. A fully connected graph is established based on these features, and the values of the edge labels are obtained by updating the nodes and edge features in the fully connected graph. Finally, the tool wear condition is predicted through the sample label of the support set and the predicted value of the edge connected with the query sample using a weighted voting method. The effectiveness of the proposed EGNN-based TCM method was demonstrated by its application to milling TCM experiments, and the results indicated that the proposed method outperformed three state-of-the-art methods (CNN, AlexNet, and ResNet) with small samples.
A Lego® Mach–Zehnder interferometer with an Arduino detector
Authors: Feenstra Louw , Julia Cramer , Logman Paul
Published: January 2021

In this paper, a Lego®-based interferometer, developed by a first-year bachelor physics student, is presented. The interferometer is home-built at low cost, using household items such as glass panes for beamsplitters and reflecting smartphone logos for mirrors. It is able to produce stable and visible fringes, of which shifting can be monitored. The presented methods allow students to build and conduct adequate optical experiments without the need for expensive optics lab materials, making them deployable in distance learning. Moreover this interferometer demonstrates the educational value of a free experimental assignment.
The role of excited electronic states in ambient air ionization by a nanosecond discharge
Authors: Minesi N , Mariotto P , Pannier E , Stancu G D , Laux C O
Published: January 2021

The mechanism of air ionization by a single nanosecond discharge under atmospheric conditions is studied using numerical simulations. The plasma kinetics are solved with ZDPlasKin and the electron energy distribution function is calculated with BOLSIG+. The model includes the excited electronic states of O and N atoms, which are shown to play the main role in plasma ionization for n
e > 1016 cm−3. For electric fields typical in nanosecond discharges, a non-equilibrium plasma (T
e > T
gas) is formed at ambient conditions and remains partially ionized for about 12 nanoseconds (n
e < 1016 cm−3). Then, the discharge abruptly reaches full ionization (n
e ≈ 1019 cm−3) and thermalization (T
e = T
gas ≈ 3 eV) in less than half a nanosecond, as also encountered in experimental studies. This fast ionization process is explained by the electron impact ionization of atomic excited states whereas the fast thermalization is induced by the elastic electron–ion collisions.
High performance wafer scale flexible InP double heterogeneous bipolar transistors
Authors: Wu LiShu , Dai JiaYun , Wang Yuan , Kong YueChan , Chen TangSheng , Zhang Tong
Published: January 2021

This letter reports on the first demonstration of wafer scale flexible InP double heterogeneous bipolar transistors (DHBTs) with record cut-off frequency (f
T) and maximum oscillation frequency (f
MAX). The as-fabricated DHBTs on 3-inch InP bulk substrate are separated by epitaxial layer lift-off, followed by adhesive bonding onto flexible substrate. Radio frequency measurements reveal that the InP DHBTs on flexible substrate exhibit a f
T of 337 GHz and f
MAX of 485 GHz, representing the highest f
T and f
MAX ever reported in flexible electronics. Moreover, InP DHBTs on flexible substrate have good consistency and the functional transistor yield is more than 73%. The results provide ways to accelerate the time for flexible electronics toward future applications working at multi-gigahertz range.
Role of electrons non-extensivity on the fully nonlinear dust-ion acoustic solitary waves
Authors: Abdelwahed H G , Sabry R , Alsarhan A F
Published: January 2021

Fully nonlinear dust-ion acoustic solitary waves are investigated in a multi-species plasma model comprised of warm positive mobile ions with a non-zero ion temperature, non-extensive electrons and negatively charged dust particles. Basic plasma system is reduced to a single energy integral using pseudopotential analysis without sorting to any perturbations or approximation scheme. Existence regions of positive and negative dust-ion acoustic waves as well as soliton profile are determined through phase portrait analysis and numerical investigations. Effects of the electrons non-extensivity parameter, temperature ratios, fractional densities and soliton speeds on both soliton polarities profiles and their corresponding pseudopotentials show that existence domains and soliton characteristics are inherently affected in the considered plasma regime. Bifurcation analysis as well as numerical investigations, revealed that only negative soliton polarities exist for plasma parameters observed in the Earth’s auroral ionosphere.
Tenfold increase in the fusion triple product caused by doubling of toroidal magnetic field in the spherical tokamak Globus-M2
Authors: Kurskiev G.S. , Gusev V.K. , Sakharov N.V. , Balachenkov I.M. , Bakharev N.N. , Bulanin V.V. , Chernyshev F.V. , Kavin A.A. , Kiselev E.O. , Khromov N.A. , Minaev V.B. , Miroshnikov I.V. , Patrov M.I. , Petrov A.V. , Petrov Yu.V. , Shchegolev P.B. , Telnova A.Yu. , Tokarev V.A. , Tolstyakov S.Yu. , Tukhmeneva E.A. , Varfolomeev V.I. , Yashin A.Yu. , Zhiltsov N.S.
Published: January 2021

The current work reports on the significant rise of the fusion triple product in experiments carried out on the compact spherical tokamak (ST) Globus-M2 with a twofold increase in the toroidal magnetic field. A tenfold rise in the n . T . τ
E product was recorded during an increase in the magnetic field from 0.4 to 0.8 T and the plasma current from 0.25 to 0.4 MA at an unchanged auxiliary heating power value. Limited reasons may affect this positive trend, among which are energy confinement improvement and an increase in the efficiency of neutral beam heating. Despite the increase in the magnetic field, the neutral beam injection (NBI) led to clear and reproducible transition to the H-mode accompanied by a decrease in the turbulence level at the plasma edge. It was experimentally confirmed that strong dependence of the energy confinement time on the magnetic field value is conserved at a higher magnetic field approaching 0.8 T. Enhancement of energy confinement is connected to a collisionality (ν
*) decrease. While for conventional tokamaks the confinement dependence on collisionality becomes weaker with decreasing ν
* dependence, in the ST, in contrast, we observe its strengthening.
Life loss per death of respiratory disease attributable to non-optimal temperature: results from a national study in 364 Chinese locations
Authors: Li Xing , Zhou Maigeng , Yu Min , Xu Yanjun , Li Junhua , Xiao Yize , Huang Biao , Hu Jianxiong , Liu Tao , Guan Weijie , Chen Siqi , Xu Xiaojun , Lin Lifeng , Hu Ruying , Gong Weiwei , Hou Zhulin , Jin Donghui , Qin Mingfang , Yin Peng , Wang Lijun , Xu Yiqing , Xiao Jianpeng , Zeng Weilin , Guo Lingchuan , Wang Qiong , He Guanhao , Huang Cunrui , Zhou Chunliang , Ma Wenjun
Published: January 2021

Many studies have linked temperature with respiratory deaths, but epidemiological evidence of temperature-attributable years of life lost (YLL) from respiratory diseases is limited. Daily respiratory YLL rates were calculated using mortality data from 364 locations of China during 2006–2017, and meteorological data were collected for the same period. First, the distributed lag non-linear model (DLNM) was applied to estimate specific temperature-respiratory YLL rate associations in each location. Then multivariable meta-analysis was conducted to pool the location-specific estimates. Finally, we calculated the average life loss per death (LLD) to quantify the respiratory mortality burden of non-optimal temperature. Subgroup analyses were conducted by gender, age, region and cause of death. Inversely J-shaped association was observed between non-optimal temperature and respiratory YLL rate in China. The minimum YLL-rate temperature was 26.9 °C nationwide. An average of 1.37 years (95% CI: 1.06–1.65) LLD was attributable to non-optimal temperatures with 2.06 years (95% CI: 1.57–2.60) for pneumonia, 2.03 years (95% CI: 1.76–2.31) for chronic lower respiratory infections (LRTI), 0.88 years (95% CI: 0.65–1.09) for chronic obstructive pulmonary disease (COPD), most of which was attributed to moderate cold (0.73 years, 95% CI: 0.65–0.80). LLD caused by non-optimal temperature was higher in males, the young, and north China. Exposure to non-optimal temperature increases respiratory YLL rate in China, most of which were attributed to moderate cold. People with respiratory diseases including pneumonia, chronic LRTI and COPD are vulnerable to non-optimal temperature exposure. The result of this study provides useful information to reduce temperature-related respiratory disease burden.
Nano-mechanical testing of Al-Nb metal matrix composites consolidated by high pressure torsion after annealing
Authors: Mulyukov R R , Nazarov K S , Shayakhmetov R U , Korznikova G F , Korznikova E A
Published: January 2021

Among different approaches for obtaining composite structures, one can distinguish the approach of severe plastic deformation that allows obtaining bulk structures from strongly dissimilar metals. The application of large strains is usually associated with grain refinement and, in some cases, with the formation of intermetallic phases, both factors contributing to the strength characteristics of the material. This work presents an investigation of nano-mechanical properties of an Al-Nb composite obtained by high pressure torsion and post deformational annealing. Measurements show that with an increase in the distance from the centre to the edge of the sample, the nanohardness increases from 2.4 to 3 GPa. Young’s modulus varies in the range from 182 to 197 GPa, which indicates the non-homogeneity of the composite sample. The Young’s modulus of the composite after high pressure torsion was found to be higher than that of pristine Al and Nb, which is probably due to the formation of the intermetallic Al3Nb phase, having an increased Young’s modulus according to ab-initio calculations.
Ultrasonic welding of metals: instruments, process parameters, and prospects of welding of ultrafine grained materials
Authors: Mukhametgalina A A , Murzinova M A , Nazarov A A , Parkhimovich N Yu , Samigullina A A , Shayakhmetova E R , Zhilyaev A P
Published: January 2021

The results of studies on the development of instruments for ultrasonic welding (USW) of metals, which is the basic process for ultrasonic additive manufacturing, are presented. The influence of process parameters (static loading and welding time) on the microstructure and strength of joints produced by USW of commercially pure copper, nickel and titanium is studied. Preliminary results of the first studies on the USW of metals in an ultrafine grained (UFG) state are presented and the prospects of using UFG metals in the ultrasonic additive manufacturing are evaluated.
Synthesis and Characterization of (Ag2S)x(ZnS) Heteronanostructures
Authors: Sadovnikov Stanislav I. , Gerasimov Eugeny Yu.
Published: January 2021

(Ag2S)x(ZnS) heteronanostructures were synthesized by two-stage chemical codeposition of silver and zinc sulfides using aqueous solutions of zinc nitrate, silver nitrate, sodium sulfide, trisodium citrate and Trilon B. Prepared heteronanostructures were characterized for phase composition and nanoparticles size using X-ray diffraction and the high-resolution transmission electron microscopy. The size of Ag2S nanoparticles in the obtained heteronanostructures depends on the ratios of reagent concentrations and ranges from 9 to 30 nm, the size of ZnS nanoparticles is equal to 4-5 nm.
Effect of nanostructuring on the thermal expansion and saturation magnetization of Fe - 36% Ni and Fe - 50% Ni alloys
Authors: Krylova K A , Bitkulov I Kh , Mulyukov R R
Published: January 2021

Nanostructured samples of Fe - 36% Ni (Invar alloy) and Fe - 50% Ni alloys with a fragment size of about 100 nm were obtained by high pressure torsion using Bridgman anvils. The formation of the nanostructure leads to a decrease in the coefficient of thermal expansion of the Fe - 36% Ni and Fe - 50% Ni alloys by 2.2 and 1.2 times, respectively. Annealing of the Fe - 36% Ni alloy after nanostructuring leads to the formation of a dispersed bcc phase, which is not observed in the coarse-grained Invar alloy. The release of this phase affects the anomalous growth of thermal expansion (above the values typical for a coarse-grained Invar alloy) and the retention of saturation magnetization at temperatures above the Curie temperature of 260 °C. It is found that heating the nanostructured Fe - 50% Ni alloy above the Curie temperature (460 °C) saves the saturation magnetization. By analogy with the results for the Fe - 36% Ni, it can be assumed that this is due to the appearance of a dispersed bcc ferromagnetic phase. Detailed structural analysis will be carried out in future works.
Effect of friction stir processing on the strengthening of the 2024 aluminum alloy
Authors: Valeeva A Kh , Akhunova A Kh , Imayev M F , Fazlyakhmetov R F
Published: January 2021

A study of the influence of the tool pin length on the strengthening of the 2024 aluminum alloy under friction stir processing (FSP) was carried out. According to the results of real and model experiments, it was found that for a workpiece with a thickness of 3.0 mm, the necessary and sufficient pin length is 2.0 mm, because in this case, mixing throughout the thickness of the workpiece is provided. It was found that during the FSP of the 2024 alloy, solid-solutional hardening of the processed area occurred due to the release of particles of intermetallic phases.
Surface polymorphism of silica nanoparticles
Authors: Syzrantsev V V , Paukstis E A , Larina T V
Published: January 2021

A comparative study was performed on the surface properties of silica nanoparticles synthesized by various methods using FTIR, UV-Vis DRS and X-ray diffraction. It is shown that different methods of synthesis affect the surface properties of nanoparticles while maintaining the phase composition of the material. It is also shown that the nanoparticles of each material have unexpected properties. In particular, a significant difference was observed in the concentration of Lewis centres for the samples. This variation in properties indicates the importance of accurately characterizing the surface properties of nanoparticles as they determine the interactions of nanoparticles with other materials.
Modified hybrid CdSe/ZnS quantum dots and their size dependent unique characteristics
Authors: Ishankulov A F , Shamilov R R , Galyametdinov Yu G , Mukhamadiev N K
Published: January 2021

In this study, CdSe-based hybrid CdSe/ZnS quantum dots were synthesized. Their optical properties have been characterized using the absorption and luminescence spectroscopy methods. When the ZnS shell was grown on the surface shell of CdSe nanoparticles, the photoluminescence stability and the shelf life of the quantum dots increased significantly. The energy of the outer shell has increased. The absorption and luminescence spectra shifted to a shorter wavelength range. The size of the nucleus decreased from 3.7 nm to 2.8 nm. The surface was stabilized with oleic acid as an active ligand. After stabilization with a surfactant, the average total hydrodynamic size of the nanoparticles increased.
Study of the deformation behavior and structure formation of Ti-Zr-Nb shape memory alloy
Authors: Sheremetyev V A , Akhmadkulov O , Komarov V S , Korotitsky A V , Galkin S P , Andreev V A , Prokoshkin S D
Published: January 2021

The deformation behavior and structure formation of the Ti-19Zr-14Nb (in at. %) shape memory alloy have been studied. The as-cast ingot was subjected to multi-axis forging at a billet heating temperature of 1050 °C and then to rotary forging at 600 °C. Plastometric compression tests of the forged alloy were carried out at a strain rate 0.1 s−1 at temperatures of 600-1000 °C, the strain degree is not more than 0.7. The obtained flow curves and the results of studying the grain structure and hardness were used to determine the features of the thermomechanical behavior of the material. The study of the microstructure showed that under these processing conditions, the processes of dynamic polygonization and dynamic recrystallization occur simultaneously. According to the obtained hardness measurement results, it can be assumed that in order to achieve a low Young’s modulus and perfect superelastic behavior, deformation must be carried out at temperatures of 700-800 °C.
Superplastic behaviour and solid state weldability of a polycrystalline heavily alloyed nickel-base superalloy
Authors: Mukhtarov Sh Kh , Imayev V M , Ganeev A A , Shakhov R V , Logunov A V
Published: January 2021

Effective thermomechanical treatment has been developed for the heavily alloyed Ni- base superalloy produced via ingot metallurgy with a high content of γ’-forming elements. It allowed us to eliminate dendritic segregation and to obtain a uniform fine-grained structure with a γ grain size of d=5-15 μm. In the fine-grained condition the superalloy exhibited superplastic properties at 1125-1175°C (δ>300%, σ=10-27 MPa, m>0.3). Pressure welding experiments were performed at 1150°C for samples with the fine-grained structure. The solid-phase joint was formed only after compression to the strain of 50%. It was shown that insertion of a nanocrystalline interlayer of the same superalloy between the welded samples facilitated formation of the solid-phase joint.
Experimental study of the influence of different carbon content on the shrinkage kinetics and structure evolution of ultralow-cobalt hard alloys during spark plasma sintering
Authors: Lantsev E A , Nokhrin A V , Boldin M S , Malekhonova N V , Andreev P V , Smetanina K E , Popov A A
Published: January 2021

The features of the compaction of plasma-chemical WC - (0.3; 0.6; 1) %Co nanopowders with the addition of 0.3 and 0.5% graphite during high-speed spark plasma sintering have been investigated. It was shown that an increased concentration of oxygen adsorbed on the surface of plasma-chemical nanoparticles during mixing with graphite, as well as the effect of graphite itself, which leads to a decrease in the activation energy of sintering due to a decrease in the intensity of the formation of particles of the η-phase in the “oxidized” WC-Co nanopowders, are the main structure features of ultralow-cobalt hard alloys. Samples of finegrained ultralow-cobalt hard alloys with increased hardness and fracture toughness were obtained (for a WC-0.6% Co-0.3% C hard alloy with an average grain size of ∼ 1-1.5 pm, the hardness is Hv = 20.2-20.5 GPa with a minimum crack resistance coefficient K
ic
= 9.2-10.4 MPa-m1/2).
Molecular dynamics simulation of diffusion in Mg-Al system under pressure
Authors: Polyakova P V , Baimova J A
Published: January 2021

The Mg-Al composite material possesses a large potential value in practical application due to its excellent properties. Molecular dynamics with the embedded atomic method potentials is applied to study aluminium-magnesium (Al-Mg) interface bonding during deformation. Study of fabrication techniques to obtain composites with improved mechanical properties, careful investigation of phase composition, dynamics and kinetics are of high importance. The loading scheme used in the present work is the simplification of the scenario, experimentally observed previously to obtain Al/Cu composites. It is shown that shear strain has a crucial role in the diffusion process. The results indicated that the symmetrical diffusion took place in the Mg-Al interface during deformation. Tensile tests showed that fracture took place in the Mg part of the final composite sample, which means that the interlayer region where the mixing of Mg and Al atoms observed is much stronger than the pure Mg part.
Model calculation of the phase diagram of Cu-Te
Authors: Kurbangulov A R , Tsygankova L V , Tikhonov E V , Bikkulova N N , Safargaliyev D I , Nigmatullina G R , Akmanova G R
Published: January 2021

The paper presents the results of model calculations of the phase diagram of the Cu-Te system. A comparative analysis of the experimentally obtained data with theoretical calculations for the obtained model compounds is presented.
Crystallogeometry and energy of planar superstructure defects of ternary alloys
Authors: Khalikov A R , Nguen V T , Valitov V A , Dmitriev S V
Published: January 2021

Planar superstructure defects have a great influence on the mechanical and functional properties of ternary Heusler alloys; however, their complete crystallogeometric and energy analysis is lacking in the literature. In this work, Heusler alloys of stoichiometric composition X2YZ of the L21 superstructure are analysed. An expression is given for finding the planes of occurrence of all possible planar superstructure defects. It is established that among them there are only shear and thermal antiphase boundaries. The results obtained are useful for analyzing slip systems of the considered family of alloys and the configuration of magnetic domain walls.
Peierls-Nabarro potential for kinks in nonlinear chains
Authors: Bebikhov Yu V , Dmitriev S V
Published: January 2021

The aim of this work is to review various discrete models supporting topological solitons, in which the Peierls-Nabarro potential can be significantly lowered or even reduced to zero. These theoretical results are discussed in relation to the Peierls stresses for dislocations in a variety of crystals. Derivation of the discrete models free of the Peierls-Nabarro potential has been done by a number of authors with the use of analytical calculations. Peierls stresses for dislocations in crystals described in the literature have been estimated within the framework of molecular dynamics and ab initio simulations. These theoretical results are discussed in connection with the variability of the Peierls stress in different crystals.
A6061/B4C MMCs fabrication, experimental investigation and prediction of properties
Authors: Shyn C S , Rajesh R , Dev Anand M
Published: January 2021

The growing demand for light composite materials is the new trend in engineering solicitations. The objective is to fabricate light weight composite material through less expensive method. In this work, nine different composites have been fabricated with A6061 as base matrix and reinforced with 3%/6%/9%wt%B4C having particle sizes of 30µm, 40µm and 60µm respectively. The investigation of the actual density and hardness of the fabricated composite is the major task. The densities of the fabricated composites were investigated with Two-way Analysis of Variance(ANOVA). Also the densities of the composites were predicted with Taguchi, regression and Poisson method. From all of these fabricated composites 60µm size, 9% wt B4C particle reinforced A6061/B4C composite shows lighter density and this value were nearest to Poisson predicted value.
Network in Sequential Form: Combine Tree Structure Components into Recurrent Neural Network
Authors: Zubair Swaleha , Singha Anjani Kumar
Published: January 2021

Smaller units nestled in larger units-a natural language that is hierarchically ordered. Smaller sections are replaced because of the completion of the bigger constituencies. The basic LSTM architecture does not have a clear choice for modeling the hierarchy of components as separate neurons do not require knowledge to be monitored on various time scales. The idea in this paper is to introduce inductive bias by grouping the neurons. The modifications we create to the master input vector are changed in all neurons following the order of the specified neuron and forget windows. Four activities on which we can achieve strong care unattended sorting, logical inference, and language modeling and guided syntax evaluation.