bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic study of Ceres’ collisional family candidates
Authors: Tinaut-Ruano F. , de Leon J. , Tatsumi E. , Rousseau B. , Rizos J. L. , Marchi S.
Published: November 2021

Context. Despite the observed signs of large impacts on the surface of Ceres, there is no confirmed collisional family associated with this dwarf planet. After a dynamical and photometric study, a sample of 156 asteroids were proposed as candidate members of a Ceres collisional family.

Aims. Our main objective is to study the connection between Ceres and a total of 14 observed asteroids among the candidates sample to explore their genetic relationships with Ceres.

Methods. We obtained visible spectra of these 14 asteroids using the OSIRIS spectrograph at the 10.4 m Gran Telescopio Canarias. We computed spectral slopes in two different wavelength ranges, from 0.49 to 0.80 μm and from 0.80 to 0.92 μm, to compare the values obtained with those on Ceres’ surface previously computed using the Visible and Infrared Spectrometer instrument on board the NASA Dawn spacecraft. We also calculated the spectral slopes in the same range for ground-based observations of Ceres collected from the literature.

Results. We present the visible spectra and the taxonomy of 14 observed asteroids. We found that only two of the asteroids are spectrally compatible with Ceres’ surface. Further analysis of those two asteroids indicates that they are spectrally young and thus less likely to be members of the Ceres family.

Conclusions. All in all, our results indicate that most of the 14 observed asteroids are not likely to belong to a Ceres collisional family. Despite two of them being spectrally compatible with the young surface of Ceres, further evaluation is needed to confirm or reject their origin from Ceres.
Adoption time of a maturing disruptive technology in a duopoly market
Authors: Sun Lianjia , Lin Jun
Published: November 2021

New disruptive technologies invalidate the traditional competition dimension in continuous innovation and reconstruct the competitive landscape. These technologies leave a management gap in the adoption of new technologies by competing companies. Accordingly, this research establishes a duopoly game model based on horizontal and vertical differentiations for technology competition problems with asymmetric features. Competition between firms and technologies are investigated simultaneously. We find that a profit increase from new technologies is typically eliminated by the increased technology competition. Thus, firms with competitive advantages in the old market might be late in adopting new technologies, and the competition will further delay the adoption process. We then introduce a preemption strategy for adopting disruptive technologies, and test it in both current established competition and threat competition from the entrants. Results show that leading companies might hesitate in deterring new entrants for fear of losing the leadership in the current competition. Finally, we provide a time strategy that can help the market leader maintain a leadership position with minimal losses. Our research has contributed to the studies of both the interpretation of the “innovator’s dilemma” and the direction of technology adoption research under multi-dimensional technologies and multiple competitors.
A Neurologist's Practical Approach to Cognitive Impairment
Authors: Tipton Philip W. , Day Gregory S. , Graff-Radford Neill
Published: November 2021

The global prevalence of dementia is expected to triple by the year 2050. This impending health care crisis has led to new heights of public awareness and general concern regarding cognitive impairment. Subsequently, clinicians are seeing more and more people presenting with cognitive concerns. It is important that clinicians meet these concerns with a strategy promoting accurate diagnoses. We have diagramed and described a practical approach to cognitive impairment. Through an algorithmic approach, we determine the presence and severity of cognitive impairment, systematically evaluate domains of function, and use this information to determine the next steps in evaluation. We also discuss how to proceed when cognitive impairment is associated with motor abnormalities or rapid progression.
Approach to Loss of Consciousness: Distinguishing Epileptic Seizures, Psychogenic Nonepileptic Seizures, and Syncope
Authors: Ebong Ima , Haghighat Zahra , Bensalem-Owen Meriem
Published: November 2021

Transient loss of consciousness (TLOC) is a common emergent neurological issue, which can be attributed to syncope, epileptic seizures, and psychogenic nonepileptic seizures. The purpose of this article is to outline an approach to diagnosing the most common etiologies of TLOC by focusing on the importance of the history and physical examination, as well as targeted diagnostic tests.
Approach to Neuropathic Pain
Authors: Malhotra Ashwin , Weaver Joshua
Published: November 2021

Neuropathic pain is a common chief complaint encountered by neurologists and primary care providers. It is caused by disorders involving the somatosensory nervous system. The clinical evaluation of neuropathic pain is challenging and requires a multifaceted systematic approach with an emphasis on a thorough history and physical examination to identify characteristic signs and symptoms. Ancillary laboratory investigations, targeted imaging, and electrodiagnostic studies further help identify underlying etiologies to guide specific treatments. Management of neuropathic pain encompasses treating the underlying pathology as well as symptomatic control with nonpharmacological, pharmacological, and interventional therapies. Here, we present an approach to help evaluate patients with neuropathic pain.
Approach to Common Sleep Disorders
Authors: Wang Yujie , Salas Rachel Marie E.
Published: November 2021

Sleep disorders are highly relevant in clinical practice given their prevalence as well as their impact on health outcomes and quality of life. The most common concerns are excessive daytime sleepiness, insomnia, disordered breathing, and abnormal movements or behaviors during sleep. A detailed but targeted history is vital, particularly from the sleep partner/witness. In-laboratory sleep testing (polysomnography and multiple sleep latency test) remains vital in the diagnosis of certain sleep disorders (such as sleep-disordered breathing and central hypersomnia) and in specific populations (such as in children and individuals with comorbid medical disorders). Advances in technology have allowed for a variety of methods in assessing a patient's sleep, from compact devices to evaluate for sleep apnea, wrist actigraphy, and mobile device-based applications. As the pathophysiology of various sleep disorders becomes better elucidated, disease-specific medications have been developed for these conditions. Nonetheless, a multidisciplinary approach to management is necessary, including improving sleep hygiene and cognitive behavioral therapy.
By-catch-associated demographics of two threatened seahorses from the south-east coast of India
Authors: Shalu Kannan , Dahanukar Neelesh , Raghavan Rajeev , Ranjeet Kutty
Published: November 2021

Seahorses comprise a charismatic, high-value and high conservation-concern group of fishes, whose demographics, including the dynamics of populations, are poorly studied. In this paper, we fill this key knowledge gap by determining the population dynamics of two threatened species, Hippocampus kuda and H. trimaculatus, from the south-east coast of India using samples encountered in trawl by-catch. Hippocampus kuda showed a comparatively greater asymptotic length, whereas H. trimaculatus had a greater growth coefficient and growth performance index. Further, H. trimaculatus showed two recruitment peaks (March/April and December) in a year, against a single peak (February) for H. kuda. An assessment of mortality rates (instantaneous total, natural and fishing) indicated a high vulnerability of the local population of both species to fishing pressure. Hippocampus kuda had a greater mean length at first capture than H. trimaculatus. Biomass-per-recruit analysis showed that the exploitation of H. kuda is closer to the exploitation rates under which stock will be reduced to half the unexploited biomass, suggesting their extreme vulnerability to overexploitation, even as ‘by-catch’. Demographic parameters of the two threatened seahorses indicated that even as ‘incidental catch’, these species are vulnerable to overfishing, and species-specific conservation guidelines need to be developed and their on-ground implementation and enforcement ensured.
Transactional sex among young people in Switzerland: a cross-sectional study
Authors: Surís Joan-Carles , Stadelmann Sophie , Auderset Diane , Barrense-Dias Yara
Published: November 2021

Background The aim of this research was to determine the prevalence and characteristics of youths having ever exchanged sex and to assess if there were differences depending on whether they had done it once or several times. We also investigated what they exchanged sex for and their relationship with the last person they did it with. Methods A cross-sectional national survey was carried out in Switzerland in 2017 among young adults. The 5175 participants (51% males, mean age 26.3 years) who answered the question ‘Have you ever received something or obtained an advantage in exchange for a sexual act?’ were divided into three groups: Never (96.8%), Once (1.5%) and Several (1.7%). Results In the multivariate analysis, compared to the Never group, those in the Once group were significantly more likely to be males, to have a poor mental health, to be non-exclusively heterosexual and to have had 10+ lifetime sexual partners. Those in the Several group reported the same characteristics, but were also more likely to be younger at first sexual contact, to have their parents not living together, to report a lower socioeconomic status and a history of sexual abuse, and to have ever sent sexual images/videos of themselves. They were also less satisfied with their financial situation. Conclusions Results indicate that transactional sex is a reality for some youths in Switzerland, and health professionals dealing with them should include this question in their sexual anamnesis. From a public health perspective, sexual education and prevention campaigns should include this phenomenon.
‘I’m not a tech person’
Authors: Lee Carmen , Chau Dennis
Published: November 2021

This study contributes to existing research on polymedia by probing into what we callacademic polymedia, investigating the constant availability of interpersonal, professional, and social media for constructing scholarly personas. Drawing on the technobiographical narratives of a group of Hong Kong bilingual academics, we analyze academics’ perceptions of their media choices as situated in their professional polymedia environments. In particular, we examine how choices between public and private media shape academic persona development, and the way polymedia engagement impacts the participants’ language choice for academic purposes. This study sheds light on existing research on workplace discourse and identity in sociolinguistics by offering a polymedia dimension that draws on people’s media ideology in developing their professional identities.
Polymedia repertoires of networked individuals
Authors: Tagg Caroline , Lyons Agnieszka
Published: November 2021

This article introduces the concept of thepolymedia repertoireto explore how social meaning is indexed through the interplay of communicative resources at different levels of expression (from choice of media to individual signs) in digitally mediated interactions. The multi-layered polymedia repertoire highlights how people move fluidly between media platforms, semiotic modes and linguistic resources in the course of their everyday interactions, and enables us to locate digital communications within individuals’ wider practices. The potential of our theoretical contribution is illustrated through analysis of mobile phone messaging between participants in a large multi-sited ethnography of the communicative practices of multilingual migrants working in linguistically diverse UK city neighbourhoods. Our analysis of mobile messaging exchanges in aday-in-the-lifeof these networked individuals reveals the importance ofdevice attentionin shaping interpersonal interactions, as well as the complex ways in which choices at different levels of a polymedia repertoire are structured by social relationships, communicative purpose and (dis)identification processes.
Polymedia and family multilingualism
Authors: Lexander Kristin Vold
Published: November 2021

This paper investigates family multilingualism in a polymedia perspective, presenting results from a study of
transnational communication among four families with Senegalese background, living in Norway. Ethnographic interview data collected in 2017
and 2018, including mediagrams, are analysed to get insight into the families’ uses of media and language. Furthermore, the moment-by-moment
language practices through which family relationships are managed and sustained are examined through fine-grained analysis of interpersonal
interaction. The paper thus both draws on and goes beyond polymedia to investigate how linguistic repertoires are developed in digital
communication. The aim is to explore ways in which this theory may help us rethink family multilingualism as digital language practices
become increasingly significant.
Appearances
Authors: Kelbert Eugenia
Published: November 2021

This article re-evaluates the theoretical import of networks of signification, one of Antoine Berman’s twelve deforming tendencies in translation. TakingJane Eyreas a case study, the article considers character description as an example of a Bermanian network and traces the physical appearance of the novel’s characters across its six Russian translations. Character description represents a network that is traceable, depends on the reader’s ability to construct a visual mental image over the course of a narrative, has a tangible impact on characterisation, and remains relevant throughout a novel. It thus offers a concrete illustration of the relevance of networks of signification as a model for the systemic interpretative potential of translation variation. This analysis paves the way for further study of Bermanian networks and the ultimate integration of this concept in translation practice.
Evolution and decline: transformation of social movements in Nigeria
Authors: Ajala Olayinka
Published: November 2021

Despite the rising academic scholarship on democracy, particularly the role played by social movements in entrenching democracy in Africa, few studies have explored the transformation of social movements after they have achieved (or come close to achieving) their stated goals. Using a case study of the Oodua Peoples Congress in Nigeria, this study argues that social movements in Africa lack the capacity to transform and often become partisan or disintegrate. The study concludes that the unique characteristics of African politics, coupled with the inability of social movements to maintain public support after initial gains, eventually weaken the movements.
Imaging of 3D objects with experimental data using orthogonality sampling methods
Authors: Le Thu , Nguyen Dinh-Liem , Schmidt Hayden , Truong Trung
Published: November 2021

This paper is concerned with imaging of 3D scattering objects with experimental data from the Fresnel database. The first goal of the paper is to investigate a modified version of the orthogonality sampling method (OSM) by Harris and Nguyen [2020 SIAM J. Sci. Comput.
42 B72–737] for the imaging problem. The advantage of the modified OSM over its original version lies in its applicability to more types of polarization vectors associated with the electromagnetic scattering data. We analyze the modified OSM using the factorization analysis for the far field operator and the Funk–Hecke formula. The second goal is to verify the performance of the modified OSM, the OSM, and the classical factorization method for the 3D Fresnel database. The modified OSM we propose is able to invert the sparse and limited-aperture real data in a fast, simple, and efficient way. It is also shown in the real data verification that the modified OSM performs better than its original version and the factorization method.
Directional manipulation of diffusio-osmosis flow by design of solute-wall and solvent-wall interactions
Authors: Wang Xin , Jing Dengwei
Published: November 2021

Understanding of diffusio-osmosis, the flow induced by a solute gradient acting in narrow interfacial layers at a nanoscale solid-liquid interface, is of great value in view of the increasing importance of micro- and nano-fluidic devices and self-propelling particles. Using molecular dynamics simulations, we employ an appropriate strategy for direct simulation of diffusio-osmosis flows, mimicking a realistic experiment without any assumed external forces. It allows us to obtain reliable flow details, which are hard to obtain in experiments. We found that the solvent-wall interaction, previously overlooked in the classical paradigm, plays a critical role in the diffusio-osmosis process. In particular, diffusio-osmosis is controlled by the interaction difference between the solute-wall and solvent-wall. When the solute-wall interaction is stronger (weaker) than the solvent-wall, a surface excess (depletion) of solute particles on the solid-liquid interface is formed, which induces diffusio-osmosis flow towards a low (high) concentration. We modified the classical Derjaguin expression to include the effect of nanoscale hydrodynamics boundary conditions for the accurate prediction of diffusio-osmosis characteristics. Overall, our results provide clear guidance for controlling fluid flow and manipulating the motion of colloids under tunable solute concentrations.
Compton-like dark photon production in electron–nucleus collisions
Authors: Oliveira C P , Hadjimichef D , Machado M V T
Published: November 2021

The Compton-like production of massive dark photons is investigated in ultrarelativistic electron–ion collisions by considering the kinetic mixing between the dark photon and the standard model photon. The quasi-real photons in the heavy ion are described by the equivalent photon approximation, and the model is employed to calculate the integrated cross section and event rates as a function of the dark photon mass, m

γ′, and mixing parameter, ɛ. Predictions are shown for electron–ion colliders (EICs) in the mass range 100 ⩽ m

γ′ ⩽ 500 MeV. Numerical results are provided within the kinematic coverage of the planned machines: an EIC in China (EicC), a polarized EIC at Jefferson Lab (JLEIC), an EIC/USA (EIC), a large hadron electron collider (LHeC) and a future circular collider (FCC-eA). It complements existing search strategies for dark photons in the considered mass interval.
Pair production of magnetic monopoles and stable high-electric-charge objects in proton–proton and heavy-ion collisions
Authors: Song Wen-Yi , Taylor Wendy
Published: November 2021

We describe pair-production models of spin-0 and spin-½ magnetic monopoles and high-electric-charge objects (HECOs) in proton–proton (pp) and heavy-ion collisions, considering both the Drell–Yan (DY) and the photon-fusion processes. In particular, we extend the DY production model of spin-½ HECOs to include Z
0-boson exchange for pp collisions. Furthermore, we explore spin-½ and, for the first time, spin-0 production in ultraperipheral heavy-ion collisions. With matrix element calculations and equivalent photon fluxes implemented in MadGraph5_aMC@NLO, we present leading-order production cross sections of these mechanisms in

s

=
14

TeV pp collisions and

s

NN

=
5.5

TeV ultraperipheral lead–lead collisions at the LHC. While the mass range accessible in ultraperipheral lead–lead collisions is much lower than that in pp collisions, we find that the theoretical production cross sections are significantly enhanced in the former for masses below 82 GeV.
Highly stretchable-compressible coiled polymer sensor for soft continuum manipulator
Authors: Youn Jung-Hwan , Mun Heeju , Jang Seung-Yeon , Kyung Ki-Uk
Published: November 2021

In recent years, soft continuum robots have become emerging research hotspots, but sensing of the robot shape needs to be addressed for precise control. To solve this problem, we present an optical coiled polymer sensor that can measure strain based on macro bending power loss. Proposed sensor is fabricated by coiling and annealing a polymer optical fiber of diameter 0.25 mm. Under applied strain, the bending curvature of the coiled sensor changes which leads to light intensity change. Due to its coiled design, the proposed sensor is highly stretchable and can measure both tensile and compressive strain of the coiled sensor structure in a wide range (>250%). Static and dynamic responses of the proposed sensor were observed by controlling the design parameters, such as spring diameter and number of coils. Fabricated coiled polymer sensor with a light-weight (<0.5 g) and compact structure showed a high stretchability-compressibility, high stability, and low hysteresis error. By placing three fabricated sensors inside the soft continuum manipulator, a 3-degree-of-freedom (DOF) configuration including bending and torsion motions can be obtained. We used an artificial neural network to derive the relationship between the sensor outputs and the 3 DOFs configuration of the soft continuum manipulator. The results showed that the configuration of the soft continuum manipulator can be obtained in real-time with high accuracy (error < 2.17%).
OPCL coupling of mixed integer-fractional order oscillators: tree and chain implementation
Authors: Adelakun Adedayo O
Published: November 2021

Controlling coupled oscillators and their application are important in diverse areas of nonlinear science and technology. In this paper, a unidirectional Open-Plus-Closed-Loop coupling (OPCL) scheme in controlling two mixed oscillators with emphasis on fractance and integer-order configurations was introduced. The appropriate choice of the controller between coupled non-identical oscillators is justified to achieve the coexistence of anti-phase and complete synchronization via amplitude death. The possibility of controlling one response variable, keeping the other pairs of variable undisturbed are deduced with different configurations. This type of mixed synchronization emanated from coupled integer and fractional-order Sprott-A oscillators without interception and loss of stability. The main novelty in this work is the analog implementation for the coupled integer-order, tree, and chain configurations which are simulated and discussed extensively.
Electron beam modeling and analyses of the electric field distribution and space charge effect
Authors: Jiang Yueling , Dong Quanlin
Published: November 2021

In electron beam technology, one of the critical focuses of research and development efforts is on improving the measurement of electron beam parameters. The parameters are closely related to the generation, emission, operation environment, and role of the electron beam and the corresponding medium. In this study, a field calculation method is proposed, and the electric field intensity distribution on the electron beam’s cross-section is analyzed. The characteristics of beam diffusion caused by the space charge effect are investigated in simulation, and the obtained data are compared with the experiment. The simulation demonstrated that the cross-sectional electric field distribution is primarily affected by the electron beam current, current density distribution, and electron beam propagation speed.
Carbon fiber electrodes for intracellular recording and stimulation
Authors: Huan Yu , Gill Jeffrey P , Fritzinger Johanna B , Patel Paras R , Richie Julianna M , Della Valle Elena , Weiland James D , Chestek Cynthia A , Chiel Hillel J
Published: November 2021

Objective. To understand neural circuit dynamics, it is critical to manipulate and record many individual neurons. Traditional recording methods, such as glass microelectrodes, can only control a small number of neurons. More recently, devices with high electrode density have been developed, but few of them can be used for intracellular recording or stimulation in intact nervous systems. Carbon fiber electrodes (CFEs) are 8 µm-diameter electrodes that can be assembled into dense arrays (pitches ⩾ 80 µm). They have good signal-to-noise ratios (SNRs) and provide stable extracellular recordings both acutely and chronically in neural tissue in vivo (e.g. rat motor cortex). The small fiber size suggests that arrays could be used for intracellular stimulation. Approach. We tested CFEs for intracellular stimulation using the large identified and electrically compact neurons of the marine mollusk Aplysia californica. Neuron cell bodies in Aplysia range from 30 µm to over 250 µm. We compared the efficacy of CFEs to glass microelectrodes by impaling the same neuron’s cell body with both electrodes and connecting them to a DC coupled amplifier. Main results. We observed that intracellular waveforms were essentially identical, but the amplitude and SNR in the CFE were lower than in the glass microelectrode. CFE arrays could record from 3 to 8 neurons simultaneously for many hours, and many of these recordings were intracellular, as shown by simultaneous glass microelectrode recordings. CFEs coated with platinum-iridium could stimulate and had stable impedances over many hours. CFEs not within neurons could record local extracellular activity. Despite the lower SNR, the CFEs could record synaptic potentials. CFEs were less sensitive to mechanical perturbations than glass microelectrodes. Significance. The ability to do stable multi-channel recording while stimulating and recording intracellularly make CFEs a powerful new technology for studying neural circuit dynamics.
A fast muon tagger method for Imaging Atmospheric Cherenkov Telescopes
Authors: Venere L Di , Giavitto G , Giordano F , López-Coto R , Pillera R
Published: November 2021

The Cherenkov Telescope Array (CTA) will be the next major observatory for Very High Energy gamma-ray astronomy. Its optical throughput calibration relies on muon Cherenkov rings. This work is aimed at developing a fast and efficient muon tagger at the camera level for the CTA telescopes. A novel technique to tag muons using the capabilities of silicon photomultiplier Compact High-Energy Camera CHEC-S, one of the design options for the camera of the small size telescopes, has been developed, studying and comparing different algorithms such as circle fitting with the Taubin method, machine learning using a neural network and simple pixel counting. Their performance in terms of efficiency and computation speed was investigated using simulations with varying levels of night sky background light. The application of the best performing method to the large size telescope camera has also been studied, to improve the speed of the muon preselection.
Critical Temperature in Zigzag Graphene Nanoribbon: a First-principles Study
Authors: Prayitno T B , Budi E
Published: November 2021

The critical (Néel) temperature in the zigzag graphene nanoribbon was calculated using the mean-eld approximation within the generalized Bloch theorem. This calculation was carried out over the Brillouin zone of the magnon spectrum. We found a nearly at magnon dispersion at the high energy in one-third of the Brillouin zone. Our calculation showed the critical temperature below room temperature, in good agreement with the prediction in the previous works. Our last work (Prayitno 2021 Physica E 129 114641) revealed that the critical temperature may be enhanced by increasing the ribbon width. In this brief report, we justified that the critical temperature becomes almost constant up to a certain ribbon width. This result indicates that the critical temperature in the graphene nanoribbon will never reach room temperature for any ribbon widths, thus it is likely difficult to apply pristine graphene nanoribbon in any practical devices working near room temperature.
The Role of Symmetry in Non-Hermitian Scattering1
Authors: Ruschhaupt Andreas , Simon Miguel A , Kiely Anthony , Gonzalo Muga J
Published: November 2021

We review recent work on asymmetric scattering by Non-Hermitian (NH) Hamiltonians. Quantum devices with an asymmetric scattering response to particles incident from right or left in effective ID waveguides will be important to develop quantum technologies. They act as microscopic equivalents of familiar macroscopic devices such as diodes, rectifiers, or valves. The symmetry of the underlying NH Hamiltonian leads to selection rules which restrict or allow asymmetric response. NH-symmetry operations may be organized into group structures that determine equivalences among operations once a symmetry is satisfied. The NH Hamiltonian posseses a particular symmetry if it is invariant with respect to the corresponding symmetry operation, which can be conveniently expressed by a unitary or antiunitary superoperator. A simple group is formed by eight symmetry operations, which include the ones for Parity-Time symmetry and Hermiticity as specific cases. The symmetries also determine the structure of poles and zeros of the S matrix. The ground-state potentials for two-level atoms crossing properly designed laser beams realize different NH symmetries to achieve transmission or reflection asymmetries.
Prediction of undrained shear strength and correlation in between soil parameters
Authors: Yimer Yimam Mohammed , Paul Makesh A. , Muhammed SalihaShukri
Published: November 2021

Correlation of soil parameters has undeniable benefit in the determination of engineering properties of soil to solve problems in geotechnical Engineering area. The tests were conducted within geotechnical laboratory. These tested soil parameters, used in the correlation analysis are unconfined compressive strength, bulk unit weight and dry unit weight. The aim of this study is proposing a relationship in between the strength parameter with some of the index properties of soils using statistical regression analysis. The linear regression analyses have been done for prediction of unconfined compressive strength (qu
) from bulk and dry unit weight as model-1 and model-2 respectively. And dry unit weight was predicted from bulk unit weight as model-3. Model-4 represents the multiple linear regression analysis to predict qu
. The health of developed models is measured by coefficient of determination (R
2) values. Though, model-1, model-2, model-3 and model-4 have R – squared values of 0.9112, 0.9333, 0.9109 and 0.9452 respectively. Therefore, they are correlated strongly and positively. The prediction of unconfined compressive strength of these soils correlated in linear regression, are fairly determined with Model-2 compared with model-1 and model-4 (MLR).
Mechanical and Physical Properties of Khaya senegalensis Solid Fuel Pellet with Different Binder Percentages
Authors: Binti Ismail Ras Izzati , Shaari Abd Razak , Yee Khor Chu , Mohamed Alina Rahayu , Abd Rahim Muhammad Syakirin Bin , Leng Lee Yit , Wan Draman Wan Nur A’Tiqah , Makhtar Nur Lailina , Razak Norawanis Abd , Jamalludin Mohd Riduan
Published: November 2021

The characteristics of the solid fuel pellets, such as its strength, durability and density can be used to assess its quality. During the transport and storage, pellets with low strength and durability produces dusts and ultimately resulting in equipment blockage, high pollution emissions, and an increased risk of fire and explosion. Therefore, pellet manufacturing process should be given priority to improve pellet quality. The use of binder in the production of pellets will aid in improving pellet quality. Therefore, this study investigates the influence of different binder percentages on the mechanical properties of K. senegelensis fuel pellets. Durability, unit density, bulk density and diametral compressive strength testing were carried out in compliance with international standards. It was discovered that pellets containing 4% cassava starch binder produces better results, particularly in terms of durability and compressive ldiametral strength.
Solidification characteristics in a spherical capsule integrated with pin fins and rectangular fins - a comparative study
Authors: Premnath D , Rodrigues Jestin Merril , Thakur Aashim
Published: November 2021

This study aims at investigating the solidification characteristics in a spherical capsule with pin fins and rectangular fins of same length and volume immersed in a constant temperature bath (-6°C, -9°C, -12°C). The fins are made of copper and are attached to the inner surface of the spherical capsule. The fin lengths correspond to the annulus fill volume margin of 75% taken on the inside wall of the spherical container. The findings showed that the overall solidification period of the capsules with rectangular fins was reduced. Also, the subcooling phenomena is completely eliminated at bath temperature of -6°C. Results also indicated that 50% PCM mass is reduced effectively with the provision of fins. Thus, with the employment of rectangular fins better potential energy savings can be attained when operated at partial charging mode at higher bath temperature.
Charge Dissipation Behavior on the Insulating Polyimide Backsheet in Photovoltaic System
Authors: Cao De-Kun , Zhang Jia-Wei , Wang Shaoran , Dong Gang , Ni Hongwei , Du Guoguang
Published: November 2021

Deterioration of electric properties will be generated by the accumulation of surface charge on photovoltaic backsheet in the insulating system of photovoltaic (PV) system. The phenomena of potential induced degradation (PID) could be verified in the insulating Polyimide (PI) backsheet of PV module. In the field of photovoltaic system, PI has been found a special insulating backsheet that work in a mild condition. If the dynamic behaviors of the charge in the insulating backsheet could be understand, unexpected flashover events will be avoided. Thus, the mechanism of surface charge decay of PI should be explored under steady condition. The effect of accumulation of surface charge was explored on PI dielectric under constant ambient temperatures in this paper. The present investigation will contribute greatly toward the early potential induced degradation phenomenon of PV system.
Experimental Analysis on Heat Release of Pulsating Heat Pipe Phase Change Regenerator with Different Working Fluids
Authors: Lu Xiaohui , Luo Xiaoxue , Cao Shibo , Zou Changzhen , Han Xiaochun
Published: November 2021

In order to improve the problems of serious energy waste and low utilization rate, this paper designs and builds an experimental platform for a pulsating heat pipe type phase change heat storage device. The temperature changes with time in the heat storage and release device of the barium hydroxide octahydrate phase change material under different working conditions is studied. The results show that during the heat release process, when the pulsating heat pipe is filled with water, the cooling water temperature rises to the highest, and the heat recovery rate is as high as 64%. Otherwise, the initial temperature of the cooling water during the heat release process is studied. Result shows that the initial temperature of the cooling water increases, the longer the latent heat of phase change and the total heat release time, and the higher the temperature rise of the cooling water. The experimental design of this paper can provide a reference for researchers in related fields.
Hierarchical dispatching model of power grid under electrochemical energy storage constraints
Authors: Mo Yujie
Published: November 2021

Aiming at the hierarchical and zoning operation control of active distribution network, focusing on electrochemical energy storage, theoretical analysis and simulation research are carried out. Firstly, the basic principle of electrochemical energy storage is analyzed, and the working characteristics such as state of charge, power loss and charge discharge power are studied. Secondly, from the perspective of economic indicators, the power consumption cost of electrochemical energy storage is studied, and the objective function of global optimal dispatching of active distribution network is constructed. Then, the energy constraints and power constraints of electrochemical energy storage are studied as an important supplement to the active distribution network optimal scheduling model. Thirdly, the application of electrochemical energy storage in regional autonomous control is analyzed, and the regulation strategy of power fluctuation is studied from the perspective of standby capacity and power deviation. Finally, combined with a specific application example, the simulation analysis is given. The simulation results show that electrochemical energy storage can effectively optimize the hierarchical scheduling of active distribution network.
Research on the Influence of Shear Turbulence on the Aerodynamic Loads Characteristics of Wind Turbine
Authors: Tong Tong , Li Bangxing , Ren Xin
Published: November 2021

In order to accurately analysis the aerodynamic loads characteristics of the wind turbine under different turbulent wind conditions, the horizontal homogeneity in the flow field without a wind turbine and the numerical accuracy of the homogeneous flow field with a wind turbine were validated against the experimental results. The aerodynamic loads of the wind turbine were studied under the conditions of the uniform wind with a uniform turbulence intensity, the uniform wind with a shear turbulence intensity, the shear wind with a uniform turbulence intensity and the shear wind with a shear turbulence intensity. The results show that the increasing turbulence intensity leads to a small reduction in the torque of the wind turbine. Compared with uniform wind, shear inflow leads to a sine or cosine variation in the aerodynamic performance of the wind turbine and a reduction in the wind turbine’s thrust and torque. Compared with uniform turbulence intensity, shear turbulence intensity leads to a reduction in the wind turbine’s thrust and torque, and a more obvious phase lag effect, but it has little influence on the yawing moment and pitching moment.
Optimal Operation Of Integrated Energy System Considering Demand Response
Authors: Liang Yan , Wang Yao , Liu Hongli , Wang Peng , Jing Yongming , Li Jia
Published: November 2021

Due to the high cost of energy storage part in traditional integrated energy systems, the demand response effect is poor. The paper proposes electrolytic water hydrogen production technology and applies it to the optimal operation of integrated energy system. By optimizing the operating cost of the system through adaptive genetic algorithm, we show that when the load matching degree was increased from 50% to 70%, the system operating cost was reduced by about 15.8%, and the carbon displacement was decreased by about 35%. System operating costs, carbon emissions, and the amount of electrolytic water systems involved in the demand response have all decreased.
Impedance Reshaping and Stability Analysis of the Unbalanced Three-phase System Considering the Grid-tied Inverter based Imbalance Compensation
Authors: Jin Wei , Gao Feng , Liu Lu
Published: November 2021

Grid-tied inverters have been adopted both as the interface of renewable energy resources and as a solution to address power quality issues. To compensate the imbalance distortion caused by asymmetric local load, DQ transformation based compensation method is introduced into the control scheme of the grid-tied inverter. Taking both the inverter control scheme and circuit topology into account, the space vector based impedance modelling and stability analysis approaches are proposed in this paper to analyse the dynamic of the asymmetric system with active imbalance compensation. The proposed impedance models indicate that the compensation control method can reshape the output impedance features, and affect the stability of the system. The stability analysis results are verified in this paper by experimental results.
Test method for opening and closing time of 500kV high voltage circuit breaker under double terminal grounding condition
Authors: Yan Song , Zhang Xiaoming , Ma Kai , Su Yang
Published: November 2021

The opening and closing time test of 500kV high voltage circuit breaker can evaluate the mechanical characteristics and three-phase synchronization performance of the circuit breaker. Due to the influence of the earth resistance circuit, the traditional test method of circuit breaker opening and closing time can not be carried out when both ends are grounded. This paper first introduces the differential coil used to collect the signal, and then according to the requirements of field test, puts forward a test method for the opening and closing time of circuit breaker under the condition of double terminal grounding, and gives the basis for judging the opening and closing signal time. Finally, it compares and analyses the results of this method with the traditional high voltage circuit breaker opening and closing time test method, and obtains the conclusion of high voltage circuit breaker. The test method of grounding time division and closing time at both ends of the circuit breaker can fully meet the needs of field maintenance, which provides a new idea for the opening and closing time test of 500kV high voltage circuit breaker.
Research on Application of Pulsed Eddy Current Testing in Nuclear Power Plant Pipelines
Authors: Han Yang , Tao Yu-Chun , Yan Hai , Peng Zhi-Zhen , Liang Peng-Fei , Xu Ning
Published: November 2021

The condensate pipelines, main water supply pipelines, drain pipelines, and partial extraction pipelines of nuclear power plants are all coated with coatings on the outside of the pipelines to improve heat exchange efficiency. At present, the detection methods of ferromagnetic pipelines are mainly conventional ultrasound and ultrasonic guided waves. It is necessary to remove the insulation layer of the outer wall of the pipeline before the inspection, which leads to a prolonged inspection period and increased labor costs. This paper uses the measured and calculated values of the induced voltage to establish the optimal parameter inversion problem and combines the coupling relationship between the parameters to propose a reliable pulsed eddy current detection method for the relative wall thickness of ferromagnetic pipes. Using the pulsed eddy current detection method for the relative wall thickness of ferromagnetic pipelines proposed in this paper, the scanning detection of nuclear power plant steel pipes is compared with conventional ultrasonic testing. The detection results are reliable and suitable for non-destructive testing and evaluation of nuclear power plant ferromagnetic pipeline wall thickness corrosion thinning.
Fault Line Selection of Non-solidly Grounding System Based on EMD and Correlation Analysis of Zero Sequence Current Break-variable
Authors: Hu Guo , Jun Qin , Wu Hai , Hu Song , Xia Lei , Zhu Yajun , Xu Zhihua , Yu Jin
Published: November 2021

When a single-phase grounding fault occurs in non-solidly grounding system, the zero sequence transient current is nonlinear and non-stationary. Especially when the resonant system is grounded with high resistance, the transient quantity is weak, which brings challenges to data processing. Therefore, empirical mode decomposition (EMD) is proposed to decompose the transient quantity and obtain different intrinsic mode functions (IMF). The IMF with the largest discrimination is selected as the characteristic quantity for correlation analysis. At the same time, considering the existence of unbalanced current in the actual system, in order to avoid the influence of unbalanced current, a single-phase grounding fault line selection algorithm based on EMD decomposition and correlation analysis of zero sequence current break-variable is proposed. Finally, the effectiveness of the method is verified by simulation and field test waveforms.
Transmission corridor line safety monitoring method based on monocular vision
Authors: Wang Minzhen , Shang Ziwen , Guo Jiankai , Qiao Dongliang , Dai Wentao
Published: November 2021

Aiming at the problem of low accuracy of traditional methods in transmission corridor line safety monitoring, a transmission corridor line safety monitoring method based on monocular vision is designed. First of all, this article defines the target object of the safety monitoring of the transmission corridor line. Then, based on the monocular vision measurement to obtain the internal parameters of the camera geometry, optical characteristics, etc., the position of the power transmission corridor line security surveillance camera is calibrated, the power transmission corridor line security monitoring graphics are displayed, and the security monitoring data of the transmission corridor line is used for perception and track.Finally, the safety monitoring and early warning of transmission corridor lines are realized. The experimental results show that the monitoring accuracy of the design method is significantly higher than that of the control group, which can solve the problem of low accuracy of transmission corridor line safety monitoring by traditional methods.
An available capacity evaluation method for photovoltaic generation considering hydrogen storage
Authors: Geng Lian , Zhuang Ruxue , Yao Haowei , Cui Lu , Xia Meng , Zhao Jingyi , Jian Jiangyi , Dai Wei
Published: November 2021

With the rapid development of global photovoltaic applications in recent years, it is crucial to evaluate the photovoltaic generation capacity to achieve a secure and efficient utilization of photovoltaic resources. This paper proposes an available photovoltaic evaluation method for generation capacity in distribution networks. The evaluation model is based on the optimal power flow model, considering operational constraints with reactive power and voltage limits. A novel multi-segment boundary approximation method is proposed to solve the model and obtain the available photovoltaic generation capacity explicitly. In addition, the effect of hydrogen storage is explored to host the photovoltaic generation capacity of the distribution network. The accuracy and calculation speed of the proposed method is greatly improved compared with traditional methods. Furthermore, the proposed method can promote the utilization of photovoltaic generation and help dispatching, which guarantees security and improves economics in the distribution network. Simulations on the modified IEEE 33-bus system demonstrate the effectiveness of the proposed evaluation method.
Study on coking of High Moisture Lignite in coal fired boiler
Authors: Dou Jie
Published: November 2021

The coking problem of coal-fired boiler seriously affects the economy and safety of the boiler. At the same time, the work of poking coke after coking in the boiler poses a great threat to the personal safety of poking coke personnel, which violates the purpose of establishing “intrinsic safety” in the power industry. Therefore, it is very important to analyze the factors affecting the coking of coal-fired boiler and effectively prevent the coking of coal-fired boiler. This paper studies the coking situation of High Moisture Lignite in a certain type of coal-fired boiler, calculates the characteristics of lignite, analyzes the causes of coking, and puts forward the optimization scheme of blending combustion and the research direction of burner adjustment in operation, so as to improve the coking situation in the process of operation.