bluuebunny/crossref_metadata_2025_split huggingface dataset:
Airfoil leading edge blowing to control bow shock waves
Authors: Lozano Francisco , Paniagua Guillermo 
Published: December 2020

AbstractThis manuscript presents a detailed characterization of active control of bow shock waves via leading edge injection, including subsonic coolant ejection and the appearance of Coanda effects. The flow phenomena occurring at steady and pulsating flow injection regimes were analyzed using steady and unsteady two-dimensional Reynolds-Averaged Navier Stokes, leading to a precise evaluation of the thermal load and drag reductions. Steady supersonic injection yields the largest abatement in thermal load and aerodynamic drag, while subsonic or fluctuating ones can also provide significant improvements at reduced cooling mass flow rates. Furthermore, a Coanda effect, causing a non-symmetric flow topology, was observed and analyzed for reduced injection port size. This Coanda effect is due to the sudden expansion happening from the injection port to the main flow and it causes the flow topology at the leading edge to become non-symmetric despite the complete symmetry of the problem. This is the first time in the literature such a phenomenon is documented for a supersonic airfoil leading edge injection. Furthermore, it enables the design of novel flow control strategies for the leading edge shock topology and flow structures in supersonic flows.
Ocean acidification may be increasing the intensity of lightning over the oceans
Authors: Asfur Mustafa , Silverman Jacob , Price Colin 
Published: December 2020

AbstractThe anthropogenic increase in atmospheric CO2 is not only considered to drive global warming, but also ocean acidification. Previous studies have shown that acidification will affect many aspects of biogenic carbon uptake and release in the surface water of the oceans. In this report we present a potential novel impact of acidification on the flash intensity of lightning discharged into the oceans. Our experimental results show that a decrease in ocean pH corresponding to the predicted increase in atmospheric CO2 according to the IPCC RCP 8.5 worst case emission scenario, may increase the intensity of lightning discharged into seawater by approximately 30 ± 7% by the end of the twenty-first century relative to 2000.
Mapping the in situ microspatial distribution of ice algal biomass through hyperspectral imaging of sea-ice cores
Authors: Cimoli Emiliano , Lucieer Vanessa , Meiners Klaus M. , Chennu Arjun , Castrisios Katerina , Ryan Ken G. , Lund-Hansen Lars Chresten , Martin Andrew , Kennedy Fraser , Lucieer Arko 
Published: December 2020

AbstractIce-associated microalgae make a significant seasonal contribution to primary production and biogeochemical cycling in polar regions. However, the distribution of algal cells is driven by strong physicochemical gradients which lead to a degree of microspatial variability in the microbial biomass that is significant, but difficult to quantify. We address this methodological gap by employing a field-deployable hyperspectral scanning and photogrammetric approach to study sea-ice cores. The optical set-up facilitated unsupervised mapping of the vertical and horizontal distribution of phototrophic biomass in sea-ice cores at mm-scale resolution (using chlorophyll a [Chl a] as proxy), and enabled the development of novel spectral indices to be tested against extracted Chl a (R2 ≤ 0.84). The modelled bio-optical relationships were applied to hyperspectral imagery captured both in situ (using an under-ice sliding platform) and ex situ (on the extracted cores) to quantitatively map Chl a in mg m−2 at high-resolution (≤ 2.4 mm). The optical quantification of Chl a on a per-pixel basis represents a step-change in characterising microspatial variation in the distribution of ice-associated algae. This study highlights the need to increase the resolution at which we monitor under-ice biophysical systems, and the emerging capability of hyperspectral imaging technologies to deliver on this research goal.
Follow-Up Care for Pediatric Hearing Aid Users at an Audiology Clinic in Malawi
Authors: Brough Helen , Kachaje Tiwaope 
Published: December 2020

Purpose
Hearing loss can have a negative impact on a child's development. Hearing aids, if fitted appropriately, maintained well, and used regularly, can offer benefit to children with hearing loss. Regular reviews of hearing aid users can help to monitor a child's progress and provide timely intervention when problems arise or needs change. This study investigates the follow-up care received by children fitted with hearing aids at a clinic in Malawi.

Method
A clinical audit was done of the frequency of face-to-face follow-up appointments, following which all pediatric hearing aid users who had not recently received follow-up care were called to invite them for a review, and then a re-audit was conducted.

Results
Of the 47 children in the audit, 46 had not had a recent face-to-face follow-up appointment. Strenuous efforts were made to call those 46 children to the clinic for review: 20 caregivers agreed to bring their child for review, 10 of whom attended. It was not possible to contact 24 caregivers.

Conclusions
Reasons for low attendance for review at this service are not known, but may be related to the financial circumstances of the patients' families as well as difficulty in maintaining contact with families. It has not yet been possible to establish a system for routine follow-up care for pediatric hearing aid users at this well-established clinic in a low-income country.
Low‐complexity channel estimation for time division duplex massive multi‐user multi‐input multi‐output systems
Authors: Hawej Muamer , Shayan Yousef R. 
Published: December 2020

AbstractThis paper addresses the problem of minimum mean square error channel estimator for time division duplex massive multi‐user multi‐input multi‐output systems. It is noteworthy that, the minimum mean square error has been previously proposed for multi‐cell massive multi‐user multi‐input multi‐output channel estimation. However, the minimum mean square error estimator suffers from high computational complexity due to the large dimension of the covariance matrix inversion. In this study, low‐complexity channel estimator for time division duplex massive multi‐user multi‐input multi‐output networks is designed by using the low‐rank matrix approximation techniques. The proposed estimator is referred to as an approximate minimum mean square error estimator. Furthermore, the computational complexity of the proposed approximate minimum mean square error estimator is analysed and compared to the minimum mean square error and least square estimators. The normalised mean square error and the uplink achievable sum‐rate performance criteria are used to evaluate the performance of the proposed estimator. Finally, the simulation results show the effectiveness of the proposed estimator under two different scenarios: noise‐limited and pilot contamination. These simulation results are compared to the conventional minimum mean square error and least square estimators.
An extended winding function model for induction machine modelling considering saturation effect
Authors: Gholami Mehrdad , Shahryari Om‐Kolsoom , Tarimoradi Hadi 
Published: December 2020

AbstractWinding function (WF) method is one of the electric machines modelling methods, which is used to simulate electric machines under different conditions. It has less simulation time and memory than other methods and, at the same time, has comparable accuracy over other methods. One of the significant challenges of WF‐based models is how to model saturation. The accuracy of the fault detection method in electric machines depends on the accuracy of the model and the method used for the simulation. A new extended model of the WF is presented for saturation modelling, which considers all parts of the core including teeth, slots, and yokes. In this method, the effect of the iron parts is emulated as a partial value that is added to the length of the actual air gap. The simulation results for normal and faulty conditions are shown in two cases, with and without considering saturation effect. Then the importance of saturation modelling has been demonstrated. Simulation is done in MATLAB software. Moreover, the experimental results are shown to verify the proposed model.
Low‐carbon energy policy analysis based on power energy system modeling
Authors: Han Xiao , Qiu Jing , Sun Lingling , Shen Wei , Ma Yuan , Yuan Dong 
Published: December 2020

AbstractThe effect of carbon policies and mechanisms on the behavior of market participants and market equilibrium has been increasingly recognized, of which tax incidence is one of these important issues. Tax incidence is the market output of both producers and consumers that respond to taxes with market equilibrium, whether the tax is levied on sellers or buyers. This paper aims to study the carbon tax incidence on the transmission level of a power system based on different carbon tax collection methods in electricity market environment. A statistical demand elasticity model, power flow and carbon emission flow models are applied to simulate the electricity market equilibrium to analyze the effects of the tax levied on demand‐side or supply‐side. Furthermore, the Australian 59‐bus system is employed in the case study with four stages and four main cases. The results demonstrate that consumers share more burden of the carbon tax in all carbon tax collection methods. Moreover, the proportion of the tax burden and emission reduction effect are different in each method and degree of renewable energy capacity. The results of this paper contribute to the establishment of emission‐related energy policies toward a low‐carbon economy.
An enhanced full‐feedforward strategy to mitigate output current harmonics in grid‐tied inverters
Authors: Gharani Khajeh Kiarash , Solatialkaran Davood , Zare Firuz , Mithulananthan Nadarajah 
Published: December 2020

AbstractThe grid‐tied inverters are the most vital components in renewable energy‐based power systems. Hence, maintaining the power quality of a grid‐tied inverter output within the standard range is an ongoing challenge in the power system. The appeared individual harmonics at inverter output current caused by grid voltage harmonics depend on the inverter output equivalent admittance. This consists of a combination of admittance seen from the point of common coupling and the phase‐locked loop path. Therefore, the precise calculation of the aforementioned admittance is an inevitable requirement to design a harmonic mitigation strategy. By adding a virtual admittance to the system through modifications in the inverter control loop, the output equivalent admittance can be removed. For this purpose, in this paper, a novel full‐feedforward harmonic suppression scheme is proposed which can effectively eliminate individual harmonics injected from the grid. Consequently, the individual output current harmonics of the inverter will be effectively suppressed. Simulation and experimental results have been carried out for a typical single‐phase grid‐tied inverter to verify the efficiency of the proposed scheme against emitted harmonics from the grid.
Interval power flow calculation algorithm for multi‐terminal dc distribution networks considering distributed generation output uncertainties
Authors: Liu Qi , Wang Shouxiang , Zhao Qianyu , Wang Kai 
Published: December 2020

AbstractAn interval power flow calculation (PFC) algorithm for multi‐terminal DC distribution networks is proposed to handle the uncertainties of distributed generation output powers and loads. Firstly, an equivalent resistance is introduced to represent the effect of droop control in DC distribution networks. The power losses of the equivalent resistance are offset by adding the injection powers to droop nodes, which guarantees the precision of the equivalent resistance model. The Newton–Raphson method is used for deterministic PFC based on the equivalent resistance, and it is applicable to DC distribution networks with different kinds of network topologies and voltage source converter control modes. Secondly, based on the deterministic PFC algorithm and affine arithmetic, an interval PFC algorithm is presented to handle the uncertainties of distributed generation output powers and loads. The affine arithmetic based interval PFC algorithm not only can determine power flow intervals quickly and accurately, but also can analyse the influences of distributed generation outputs to nodal voltages. Finally, a series of test systems are used to validate the proposed algorithms. Simulation results illustrate the accuracy and efficiency of the deterministic PFC algorithm and the interval PFC algorithm for multi‐terminal DC distribution networks.
Failure investigation and asset management of combined measuring instrument transformers
Authors: Tee ShengJi , Liu Qiang , Wang Zhongdong , Hafid Fikri , Tournet Pierre 
Published: December 2020

AbstractAsset management of instrument transformers (ITs) has gained momentum in recent years due to their large population in the network and the potential adverse impacts of their increasing number of failures. This study investigates the failure cause of a family of combined measuring ITs via temperature profile simulations and consideration of moisture migration behaviour in an oil‐impregnated paper insulation system. The temperature difference experienced by an IT, particularly throughout summer, together with a relative saturation hysteresis phenomenon could have caused a lower dielectric strength that led to failures. The study also offers insights into factors influencing the probability of failures through analysis on the lifetime data from both graphical survival function plots and statistical Cox model. In‐service age, operating voltage level and environment appear to have an influence on failure rate.
Deep multi‐level up‐projection network for single image super‐resolution
Authors: Shen Yan , Zhang Liao , Chen Yun , Xie Yi , Wang Zhongli , Shao Xiaotao 
Published: December 2020

AbstractMost convolutional neural network‐based single image super‐resolution (SR) methods do not take full account of the hierarchical features of the original low‐resolution (LR) images, including the intra‐channel spatial feature information and the inter‐channel feature information, which decreases the representational capacity of the network. A deep multi‐level upprojection network (DMUN) is proposed to solve this problem. Local feature up‐projection unit is adopted in DMUN to obtain high‐resolution (HR) feature of different levels and then to reconstruct the SR image. Residual up‐projection group in DMUN mines the hierarchical LR feature information and its corresponding HR residual information recursively. A residual recorrection mechanism is further introduced, which adopts HR residual information to re‐correct HR features and enrich the details of the output image. Finally, the original residual block with spatial‐and‐channel attention mechanism is improved, which adaptively recalibrates features by considering the intra‐channel spatial relationships and the inter‐channel pixel‐wise interdependencies simultaneously. Experiments on benchmark datasets show that DMUN achieves favourable performance against state‐of‐the‐art methods.
On the issue of drawing up the energy balance of a fat-and-oil enterprise
Authors: Jalilov Rashid , Latipov Saidmurod , Choriyev Alisher 
Published: December 2020

The article deals with the issue of drawing up the energy balance of a fat and oil enterprise. The results of experimental studies are presented. The energy balance of the average consumed power in kWh and in MJ was compiled in order to obtain a generalized energy balance at the company "EUROSNAR" LLC. A nomenclature is proposed that fully covers production processes and corresponds to the currently accepted indicators of accounting and control in a market economy, and a nomogram for determining the specific consumption of heat energy per ton of seeds and oils for production in general.
It has been substantiated that one of the ways to solve the problem of improving the reliability and accuracy of forecasts of indicators of the energy balance of an industrial enterprise is their forecasting, taking into account the relationship with other indicators characterizing the production process. When implementing this method, the foundations of the theory of probability and mathematical statistics were used.
Auswirkungen der COVID-19-Pandemie auf die Versorgung von HNO-Tumoren – die Patientenperspektive
Authors: Büntzel Jens , Walter Stefanie , Hellmund Herbert , Klein Michael , Hübner Jutta , Vitek Petr , Büntzel Judith , Koscielny Sven , Sesterhenn Andreas M. , Büssing Arndt 
Published: December 2020

ZusammenfassungFragestellung Die COVID-19-Pandemie hat Auswirkungen auf die Versorgung von Tumorpatienten. Wie erleben Patienten mit Kopf-Hals-Tumoren (KHT) diese Situation und welche Coping-Strategien ergeben sich?Material und Methode Wir befragten in Studie 1 während des Lockdowns (15.04.–15.05.2020) 433 Tumorpatienten nach ihren Eindrücken/Belastungen (online, standardisiert, anonym). In Studie 2 wurden 292 Patienten nach dem Lockdown (06.05.–10.06.2020) zu ihren wahrgenommenen Veränderungen, Perspektivwechseln und Coping-Strategien mit standardisierten Tools (WHO-5, MLQ-10, GrAw-7) befragt. Für beide Studien analysierten wir die KHT.Ergebnisse An Studie 1 nahmen 91 Patienten mit KHT teil, in Studie 2 wurden 84 Patienten mit KHT aufgenommen. Studie 1 zeigte im Lockdown einen hohen Druck auf die Mehrheit der Patienten mit KHT (53,8 %). Es waren Ängste bezüglich der eigenen Krankheit (39,6 %), aber auch erwartete physische (24,7 %) und psychische Folgen (21,3 %) der Pandemie. Die soziale Isolation (Besuchsverbot) wurde als ein Hauptproblem (58,5 %) beschrieben. Studie 2 bestätigte diese Belastungen auch nach dem Lockdown. Intensivere Beziehungen in der Familie (60/100 Punkten) sowie eine Zuwendung zu Natur und Stille (58/100 Punkten) wurden als entlastend beschrieben. Eine hohe Inaktivität (MLQ-10) sowie ein vermindertes Wohlbefinden (WHO-5) und eine reduzierte Achtsamkeit (GrAw-7) waren Charakteristiken der KHT, die Ansatzpunkte für eine Stärkung der Resilienz sein können.Schlussfolgerung Patienten mit KHT haben einen hohen mentalen und psychischen Druck durch die Pandemie. Ihr Blickwinkel ergänzt unsere bisherige Sicht und kann zu einer verbesserten Gesamtversorgung dieser Patienten beitragen.
Synthesis of Diarylethynes from Aryldiazonium Salts by Using Calcium Carbide as an Alkyne Source in a Deep Eutectic Solvent
Authors: Li Zheng , Ma Xiaolong 
Published: December 2020

AbstractAn efficient method for the synthesis of diarylethynes from aryldiazonium salts by using calcium carbide as an alkyne source at room temperature in a deep eutectic solvent is described. The salient features of this protocol are an inexpensive and easy-to-handle alkyne source, a nonvolatile and recyclable solvent, mild conditions, and a simple workup procedure.
Determination of the reaction coefficient in a time dependent nonlocal diffusion process
Authors: Ding Ming-Hui , Zheng Guang-Hui 
Published: December 2020

Abstract
This paper investigates the inverse reaction coefficient problem for a time dependent nonlocal diffusion equation by utilizing the nonlocal flux measurement from an accessible part of region, which is a continuation and an extension of our recent work (Zheng and Ding 2020 Inverse Problems
36 035006). The uniqueness of inverse reaction coefficient problem is proved. The variational regularization method is proposed to overcome the ill-posedness of inverse problem, and an alternating iteration method is adopted to automatically select regularization parameters. Furthermore, we use Laplace approximation method to capture the statistics information of the solution. In particular, we prove the lower bound of confidence width is rigorously estimated to characterize the reliability of the method. Finally, numerical results indicate that the proposed method could yield an accurate estimate and efficient uncertainty quantification of the solution.
Effect of band bending on topological surface transport of Bi2Te3 single crystal
Authors: Kumar Devendra , Lakhani Archana 
Published: December 2020

Abstract
Understanding the effect of surface to bulk coupling on topological surface states is important for harnessing the topological insulators for low dissipation electronics and quantum technologies. Here we investigate this effect on a low bulk carrier density Bi2Te3 single crystal using magnetoresistance, Hall resistivity, and Shubnikov–de Haas oscillations. Our results show the presence of high mobility surface bands and low mobility bulk bands. The surface states exhibit ambipolar transport without any gating. The mobility of surface states strongly depend on the nature of band bending, the upward band bending with holes as surface charge carrier exhibit large mobility while the downward band bending with electrons as surface charge carriers exhibit low surface mobility. The large mobility of surface Dirac holes is related to low surface defect density and small cyclotron mass. We also observe large magnetoresistance ∼285% due to multichannel quantum coherent transport in the bulk.
Evolution of diverse Hall effects during the successive magnetic phase transitions in Mn2.5Fe0.6Sn0.9 Kagome-lattice alloy
Authors: Liu Z H , Zhang Q Q , Zhang Y J , Zhang H G , Ma X Q , Liu E K 
Published: December 2020

Abstract
Evolution of diverse Hall effects due to successive magnetic transitions has been observed in Mn2.5Fe0.6Sn0.9 by suitable chemical substitution of Fe in Mn3.1Sn0.9. This noncollinear antiferromagnetic alloy exhibits a Neel temperature of 325 K. Upon cooling from 325 K, a magnetic phase transition from noncollinear antiferromagnetism to ferromagnetism occurs at 168 K due to the tilting of magnetization towards c axis. Above this temperature, anomalous Hall resistivity ranged from 0.6 to 1.3 μΩ cm has been observed in noncollinear antiferromagnetic state. Below this temperature, a topological Hall effect (THE) starts to appear due to the non-vanishing scalar spin chirality arising from the noncoplanar spin structure. Further decreasing temperature to 132 K, another magnetic transition happens, resulting in the coexistence of ferromagnetism and antiferromagnetism, so that a Hall plateau with large hysteresis below 70 K is yielded. A hysteresis as high as ∼80 kOe is obtained in ρ

xy
-H at 15 K. However, the Hall plateau disappears and only anomalous Hall effect (AHE) persists when further decreasing the temperature to 5 K. The present study provides a picture of diverse magneto-transport properties correlated to the variable spin structures driven by magnetic phase transitions.
The resistivity of high-Tc cuprates
Authors: Arouca R , Marino E C 
Published: December 2020

Abstract
We show that the resistivity in each phase of the high-Tc cuprates is a special case of a general expression derived from the Kubo formula. We obtain, in particular, the T-linear behavior in the strange metal and upper pseudogap phases, the pure T
2 Fermi liquid behavior observed in the strongly overdoped regime as well as in the mid-pseudogap phase. We also describe the

T

1
+
δ

behavior that interpolates the linear and quadratic behaviors in the crossover regime. We calculate the coefficients: (a) of T in the linear regime and show that it is proportional to the pseudogap transition temperature T
*(x); (b) of the T
2-term in the Fermi Liquid regime, without adjusting any parameter; and (c) of the T
1.6 term in the crossover regime, all in excellent agreement with the experimental data. From our model, we are able to infer that the resistivity in cuprates is caused by the scattering of holes by excitons, which naturally form as holes are doped into the electron background.