bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel sparse linear array based on fourth‐order cumulants for improved direction‐of‐arrival estimation
Authors: Mei Fengtong , Wang Yinsheng , Cui WeiJia , Ba Bin , Xu Haiyun
Published: June 2022

Owing to increased degrees of freedom (DOFs) and reduced mutual coupling effect, sparse linear arrays can improve the performance of direction‐of‐arrival estimation compared with uniform linear arrays. In this study, a novel sparse linear array is presented based on fourth‐order cumulants, which consists of five sparse sub‐arrays. The sensor locations of the five sub‐arrays are determined by a closed‐form expression. Closed‐form expressions of DOFs for the proposed array with any number of sensors are also derived. By optimising the allocation of sensors in each sub‐array, the DOFs of the proposed array with M sensors achieve . Because each sub‐array is sparse, the number of pairwise sensors with small separation is significantly alleviated. Theoretical analysis shows that the proposed array can provide a higher number of DOFs and is more robust in scenarios with heavy levels of mutual coupling than most sparse linear arrays. Numerical simulations are conducted to demonstrate the merits of the proposed array over other sparse linear arrays.
A proposed network of gamma-ray burst detectors on the global navigation satellite systemGalileoG2
Authors: Greiner J. , Hugentobler U. , Burgess J. M. , Berlato F. , Rott M. , Tsvetkova A.
Published: June 2022

The accurate localization of gamma-ray bursts (GRBs) remains a crucial task. Historically, improved localizations have led to the discovery of afterglow emission and the realization of their cosmological distribution via redshift measurements; however, a more recent requirement comes with the potential of studying the kilonovae of neutron star mergers. Gravitational wave detectors are expected to provide locations to not better than 10 square degrees over the next decade. With their increasing horizon for merger detections the intensity of the gamma-ray and kilonova emission also drops, making their identification in large error boxes a challenge. Thus, a localization via the gamma-ray emission seems to be the best chance to mitigate this problem. Here we propose to equip some of the second-generationGalileosatellites with dedicated GRB detectors. This saves costs for launches and satellites for a dedicated GRB network, the large orbital radius is beneficial for triangulation, and perfect positional and timing accuracy come for free. We present simulations of the triangulation accuracy, demonstrating that short GRBs as faint as GRB 170817A can be localized to 1 degree radius (1σ).
Warm ionized gas in the blue compact galaxy Haro 14 viewed by MUSE
Authors: Cairós L. M. , González-Pérez J. N. , Weilbacher P. M. , Manso Sainz R.
Published: June 2022

We investigate the warm ionized gas in the blue compact galaxy (BCG) Haro 14 by means of integral field spectroscopic observations taken with the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope. The large field of view of MUSE and its unprecedented sensitivity enable observations of the galaxy nebular emission up to large galactocentric distances, even in the important but very faint [O I] λ6300 diagnostic line. This allowed us to trace the ionized gas morphology and ionization structure of Haro 14 up to kiloparsec scales and, for the first time, to accurately investigate the excitation mechanism operating in the outskirts of a typical BCG. The intensity and diagnostic maps reveal at least two highly distinct components of ionized gas: the bright central regions, mostly made of individual clumps, and a faint component which extends up to kiloparsec scales and consists of widespread diffuse emission, well-delineated filamentary structures, and faint knots. Noteworthy are the two curvilinear filaments extending up to 2 and 2.3 kpc southwest, which likely trace the edges of supergiant expanding bubbles driven by galactic outflows. We find that while the central clumps in Haro 14 are H II-region complexes, the morphology and line ratios of the whole low-surface-brightness component are not compatible with star formation photoionization. In the spatially resolved emission-line-ratio diagnostic diagrams, spaxels above the maximum starburst line form the majority (∼75% and ∼50% in the diagnostic diagrams involving [O I] and [S II] respectively). Moreover, our findings suggest that more than one alternative mechanism is ionizing the outer galaxy regions. The properties of the diffuse component are consistent with ionization by diluted radiation and the large filaments and shells are most probably shocked areas at the edge of bubbles. The mechanism responsible for the ionization of the faint individual clumps observed in the galaxy periphery is more difficult to assess. These clumps could be the shocked debris of fragmented shells or regions where star formation is proceeding under extreme conditions.
Blazar nature of high-z radio-loud quasars
Authors: Sbarrato T. , Ghisellini G. , Tagliaferri G. , Tavecchio F. , Ghirlanda G. , Costamante L.
Published: June 2022

We report on the Swift/XRT observation and classification of eleven blazar candidates at z > 4. These sources were selected as part of a sample of extremely radio-loud quasars, with a focus on quasars with jets oriented roughly close to our line of sight. Deriving their viewing angles and their jets’ bulk Lorentz factors was crucial for a strict blazar classification, which was made possible only thanks to X-ray observations. Out of eleven sources, five show strong and hard X-ray fluxes that set the foundation for their blazar classification, while two are uncertain and three host relativistic jets that we observe just outside their beaming cone (i.e. are not strictly blazars), while one went undetected by Swift/XRT. Following this approach, we were able to trace the > ​109 M⊙ active super-massive black hole (SMBH) population hosted in jetted active galactic nuclei (AGN). At z ≥ 4, the massive jetted sources are likely predominant in the overall quasar population: this calls for a deep review of our understanding of the first SMBH formations and evolution. Jets are indeed key actors in fast accretion and must be searched for across the whole high-redshift quasar population. A note of caution must be added: radio-loudness and, in general, radio features at high redshifts seem do not seem to perfectly reflect high-energy properties. A strong effect attributed to the interaction with cosmic microwave background (CMB) radiation is surely at work, which quenches the radio emission with respect to the X-rays; however, in addition, more frequent occasions for the jet to be bent seem to play a relevant role in this regard. Thus, classifications and population studies must be carefully performed, so as to avoid interference resulting from these inconsistencies.
Magnetically gated accretion model: Application to short bursts in the intermediate polar V1223 Sgr
Authors: Hameury J.-M. , Lasota J.-P. , Shaw A. W.
Published: June 2022

Context. Some intermediate polars (IPs) show outbursts that are much shorter than those observed in normal dwarf novae, and their origin remains unclear.

Aims. We examine the case of V1223 Sgr, an intermediate polar that showed a short outburst in 1984, and compare the outburst characteristics with the predictions of the magnetospheric gating model.

Methods. We extracted outburst profiles from the American Association of Variable Star Observers (AAVSO) archival data. We used our code to compute the time-dependent evolution of an accretion disc truncated by the white dwarf magnetic field, using a simple description of the interaction between the disc and the magnetic field, as in D’Angelo & Spruit (2010, MNRAS, 406, 1208).

Results. We find that V1223 Sgr underwent a series of short outbursts, with a rise lasting for typically two to three hours, and a slightly longer decay. When applied to IPs, the model by D’Angelo & Spruit (2010, MNRAS, 406, 1208) accounts well for the observed outburst duration and intensity. However, we confirm that the model outcome depends sensitively on the assumptions of the rather poorly constrained model. We also searched the AAVSO database for short outbursts in other IPs, identifying individual short outbursts in FO Aqr, TV Col, NY Lup, and EI UMa, but no series such as those observed in V1223 Sgr. We also found a superoutburst, followed by a reflare in CTCV J2056−3014.

Conclusions. Although the magnetic–gating accretion instability model is clearly responsible for the series of V1223 Sgr short outbursts and most probably for similar events in other IPs, the model describing this process needs improvement, in particular concerning the interaction between the magnetic field of the white dwarf and the accretion disc. This difficult task might benefit from further comparison of the model outcome with additional observations that show good time coverage and time resolution.
The relativistic solar particle event on 28 October 2021: Evidence of particle acceleration within and escape from the solar corona
Authors: Klein Karl-Ludwig , Musset Sophie , Vilmer Nicole , Briand Carine , Krucker Säm , Francesco Battaglia Andrea , Dresing Nina , Palmroos Christian , Gary Dale E.
Published: June 2022

Aims.We analyse particle, radio, and X-ray observations during the first relativistic proton event of solar cycle 25 detected on Earth. The aim is to gain insight into the relationship between relativistic solar particles detected in space and the processes of acceleration and propagation in solar eruptive events.

Methods.To this end, we used ground-based neutron monitor measurements of relativistic nucleons and space-borne measurements of electrons with similar speed to determine the arrival times of the first particles at 1 AU and to infer their solar release times. We compared the release times with the time histories of non-thermal electrons in the solar atmosphere and their escape to interplanetary space, as traced by radio spectra and X-ray light curves and images.

Results.Non-thermal electrons in the corona are found to be accelerated in different regions. Some are confined in closed magnetic structures expanding during the course of the event. Three episodes of electron escape to the interplanetary space are revealed by groups of decametric-to-kilometric type III bursts. The first group appears on the low-frequency side of a type II burst produced by a coronal shock wave. The two latter groups are accompanied at higher frequencies by bursts with rapid drifts to both lower and higher frequencies (forward- or reverse-drifting bursts). They are produced by electron beams that propagate both sunward and anti-sunward. The first relativistic electrons and nucleons observed near Earth are released with the third group of type III bursts, more than ten minutes after the first signatures of non-thermal electrons and of the formation of the shock wave in the corona. Although the eruptive active region is near the central meridian, several tens of degrees east of the footpoint of the nominal Parker spiral to the Earth, the kilometric spectrum of the type III bursts and the in situ detection of Langmuir waves demonstrate a direct magnetic connection between the L1 Lagrange point and the field lines onto which the electron beams are released at the Sun.

Conclusions.We interpret the forward- and reverse-drifting radio bursts as evidence of reconnection between the closed expanding magnetic structures of an erupting flux rope and ambient open magnetic field lines. We discuss the origin of relativistic particles near the Earth across two scenarios: (1) acceleration at the CME-driven shock as it intercepts interplanetary magnetic field lines rooted in the western solar hemisphere and (2) an alternative where the relativistic particles are initially confined in the erupting magnetic fields and get access to the open field lines to the Earth through these reconnection events.
An integrated dynamic model to locate a competitive closed-loop supply chain facility under conditions of uncertainty: A case study of the auto parts industry
Authors: Ardakani Majid Alimohammadi , Naeini Mehdi Kabiri
Published: June 2022

With the expansion of competitive markets, supply chain management has become one of the critical issues facing businesses. One of the advantages of sustainable competition for companies is to make supply chain activities more efficient and effective. This paper aims at an integrated closed-loop supply chain (CLSC) problem which is multi-objective, multi-product, multi-period, and multi-level with limited capacities and uncertain conditions of demand and return products. The proposed supply chain network consists of five levels in the forward flow. There are five centers in the backward flow as well. The purpose of this network is to determine the optimal number and location of facilities required in each period and the optimal amount of the transfer flow of products or raw materials through different transportation modes between facilities. In this proposed model, three objective functions are taken into consideration. The first one minimizes all the costs. The second objective function maximizes the quality of products. The third objective function seeks to minimize the sum of deviations from the ideal score of the principal component of each supplier. The data of this research are taken from Pishro Diesel Company. To solve the proposed problem, several methods and algorithms have been used, including unscaled goal programming, boundary objectives, three single-objective meta-heuristic algorithms (PSO, RDA, and TGA), and multi-objective meta-heuristic algorithm (MOGA-II). As the results show, considering products and returned parts in products, a simultaneous practice of forward and reverse supply chains leads to better product quality, less damage to the environment, and lower costs for customers.
Our Treatment Strategy for CMC-1 Osteoarthritis
Authors: Myncke Irisa , Vanhees Mathias , Verstreken Frederik
Published: June 2022

Osteoarthritis of the carpometacarpal joint of the thumb ( CMC-1) is a common problem and many patients will seek medical attention and may eventually need surgical treatment. As no treatment option has shown consistent superiority, a variety of surgical procedures have been proposed. In this review paper we present our algorithm for the approach of symptomatic CMC-1 osteoarthritis, supported by scientific evidence and our personal experience. It is primarily based on patient demands, status of CMC-1 disease and associated problems around the thumb. The selection of a successful surgical treatment plan with restoration of a pain free and fully functional thumb is the goal. We’ll outline the pro’s and con’s of the surgical procedures and although trapeziectomy has long been the gold standard, the advent of reliable total joint arthroplasties with good short and long-term outcome reports has changed our treatment protocol completely.
Retrospective Review of Surgical Site Infections after Endoscopic Endonasal Sellar and Parasellar Surgery: Multicenter Quality Data from the North American Skull Base Society
Authors: Saleh Sara , Sullivan Stephen E. , Bellile Emily , Roxbury Christopher , Das Paramita , Hachem Ralph Abi , Ackall Feras , Jang David , Celtikci Emrah , Sahin Muammer Melih , D'souza Glen , Evans James J. , Nyquist Gurston , Khalafallah Adham , Mukherjee Debraj , Rowan Nicholas R. , Camp Samantha , Choby Garret , Gompel Jamie J. Van , Ghiam Michael K. , Levine Corinna G. , Field Melvin , Adappa Nithin , Locke Tran B. , Rassekh Christopher , Sweis Auddie M. , Goyal Neerav , Zacharia Brad , Wilson Meghan N. , Patel Shivam , Gardner Paul A. , Snyderman Carl H. , Wang Eric W. , Glancz Laurence Johann , Bagchi Ananyo , Dow Graham , Robertson Iain , Rangarajan Sanjeet V. , Michael L. Madison , McKean Erin L.
Published: June 2022

Introduction Transnasal access to the anterior skull base provides a minimally invasive approach for sellar and parasellar masses compared with its open counterparts. The unique microbiome of the sinonasal mucosa provides distinct challenges not encountered with other cranial approaches. The use of antibiotics in these cases has not been standardized, and data remain scarce regarding infectious outcomes.

Methods We conducted a multicenter retrospective analysis of shared quality data points for the endoscopic endonasal approach (EEA) for pituitary adenomas, along with other sellar and parasellar region masses that were included by participating institutions. Patient and operative characteristics, perioperative and postoperative antibiotic regimens and their durations, intraoperative and postoperative cerebrospinal fluid leak, and onset of postoperative meningitis and sinusitis were compared.

Results Fifteen institutions participated and provided 6 consecutive months' worth of case data. Five hundred ninety-three cases were included in the study, of which 564 were pituitary adenomectomies. The incidences of postoperative meningitis and sinusitis were low (0.67 and 2.87% for all pathologies, respectively; 0.35% meningitis for pituitary adenomas) and did not correlate with any specific antibiotic regimen. Immunocompromised status posed an increased odds of meningitis in pituitary adenomectomies (28.6, 95% confidence interval [1.72–474.4]).

Conclusions The results show no clear benefit to postoperative antimicrobial use in EEA, with further larger studies needed.
The Toronto Upper Gastrointestinal Cleaning Score: a prospective validation study
Authors: Khan Rishad , Gimpaya Nikko , Vargas Jose I. , Ramkissoon Anushka , Seleq Samir , Gholami Reza , Akhtar Hisham J. , Bansal Rishi , Scaffidi Michael A. , Amin Sunil , Bollipo Steven , Kral Jan , Lui Rashid , Pawlak Katarzyna M. , Sandhu Dalbir S. , Bilal Mohammad , de-Madaria Enrique , Siau Keith , Charabaty Aline , Hashim Almoutaz , Sánchez-Luna Sergio A. , Teshima Christopher W. , May Gary R. , Mosko Jeffrey D. , Walsh Catharine M. , Grover Samir C.
Published: June 2022

Background Assessment of mucosal visualization during esophagogastroduodenoscopy (EGD) can be improved with a standardized scoring system. To address this need, we created the Toronto Upper Gastrointestinal Cleaning Score (TUGCS).

Methods We developed the TUGCS using Delphi methodology, whereby an international group of endoscopy experts iteratively rated their agreement with proposed TUGCS items and anchors on a 5-point Likert scale. After each Delphi round, we analyzed responses and refined the TUGCS using an 80 % agreement threshold for consensus. We used the intraclass correlation coefficient (ICC) to assess inter-rater and test–retest reliability. We assessed internal consistency with Cronbach’s alpha and item-total and inter-item correlations with Pearson’s correlation coefficient. We compared TUGCS ratings with an independent endoscopist’s global rating of mucosal visualization using Spearman’s ρ.

Results We achieved consensus with 14 invited participants after three Delphi rounds. Inter-rater reliability was high at 0.79 (95 %CI 0.64–0.88). Test–retest reliability was excellent at 0.83 (95 %CI 0.77–0.87). Cronbach’s α was 0.81, item-total correlation range was 0.52–0.70, and inter-item correlation range was 0.38–0.74. There was a positive correlation between TUGCS ratings and a global rating of visualization (r = 0.41, P = 0.002). TUGCS ratings for EGDs with global ratings of excellent were significantly higher than those for EGDs with global ratings of fair (P = 0.01).

Conclusion The TUGCS had strong evidence of validity in the clinical setting. The international group of assessors, broad variety of EGD indications, and minimal assessor training improves the potential for dissemination.
Evaluation of the Content of Ophthalmology Fellowship Program Web sites
Authors: Alsaloum Peter , Alsaloum Matthew , Kim Tyler J. , Zheng David X. , Valentim Carolina C. S. , Muste Justin C. , Goshe Jeffrey M. , Singh Rishi P.
Published: June 2022

Purpose To assess the availability and content of fellowship program Web sites (FPWs) among ophthalmology subspecialties.

Design This is a cross-sectional study.

Subjects Web sites of all Association of University Professors of Ophthalmology-accredited fellowship programs in five subspecialties (i.e., surgical retina and vitreous; cornea, external disease, and refractive surgery; glaucoma; neuro-ophthalmology; and pediatric ophthalmology).

Methods FPWs were assessed for the presence of 26 key content criteria encompassing program demographics (n = 13), features (n = 10), and social life (n = 3). The presence of each content criterion as well as the content criteria groups were compared across subspecialties.

Main Outcome Measures The main outcome measured is the average percentage of key content criteria present among ophthalmology fellowship Web sites.

Results Among 266 accredited fellowship programs, 240 (90.2%) had Web sites. On average, Web sites reported 14.9 of 26 key content criteria (57.2%), 8.29 of 13 demographic criteria (63.8%), 5.84 of the 10 program features criteria (58.4%), and 0.705 of the 3 social life criteria (23.5%). Significant differences were identified among subspecialties in the presence of program description (p = 0.046), hospital affiliation (p < 0.001), names of current fellows (p = 0.004), case diversity (p = 0.001), and surgical statistics (p = 0.015). The average number of key criteria differed between subspecialties (p < 0.001).

Conclusion There is significant heterogeneity in program fellowship Web site content among ophthalmology subspecialties. Information regarding social life, such as wellness programs and community information, was largely absent across all disciplines. Addressing missing information on ophthalmology FPWs may help optimize program-applicant fit.
How to Perform Discriminant Analysis in Medical Research? Explained with Illustrations
Authors: Dhamnetiya Deepak , Goel Manish Kumar , Jha Ravi Prakash , Shalini Shalini , Bhattacharyya Krittika
Published: June 2022

Discriminant function analysis is the statistical analysis used to analyze data when the dependent variable or outcome is categorical and independent variable or predictor variable is parametric. It is a parametric technique to determine which weightings of quantitative variables or predictors best discriminates between two or more than two categories of dependent variables and does so better than chance. Discriminant analysis is used to find out the accuracy of a given classification system in predicting the sample into a particular group. Discriminant analysis includes the development of discriminant functions for each sample and deriving a cutoff score that is used for classifying the samples into different groups. Discriminant function analysis is a statistical analysis used to find out the accuracy of a given classification system or predictor variables. This article explains the basic assumptions, uses, and necessary requirements of discriminant analysis with a real-life clinical example. Whenever a new classification system is introduced, discriminant function analysis can be used to find out the accuracy with which the classification is able to differentiate a particular sample into different groups. Thus, it is a very useful tool in medical research where classification is required.
Maternal Deaths from COVID-19 in Brazil: Increase during the Second Wave of the Pandemic
Authors: Scheler Carlos André , Discacciati Michelle Garcia , Vale Diama Bhadra , Lajos Giuliane Jesus , Surita Fernanda Garanhani , Teixeira Julio Cesar
Published: June 2022

Objective To compare death rates by COVID-19 between pregnant or postpartum and nonpregnant women during the first and second waves of the Brazilian pandemic.

Methods In the present population-based evaluation data from the Sistema de Informação da Vigilância Epidemiológica da Gripe (SIVEP-Gripe, in the Portuguese acronym), we included women with c (ARDS) by COVID-19: 47,768 in 2020 (4,853 obstetric versus 42,915 nonobstetric) and 66,689 in 2021 (5,208 obstetric versus 61,481 nonobstetric) and estimated the frequency of in-hospital death.

Results We identified 377 maternal deaths in 2020 (first wave) and 804 in 2021 (second wave). The death rate increased 2.0-fold for the obstetric (7.7 to 15.4%) and 1.6-fold for the nonobstetric groups (13.9 to 22.9%) from 2020 to 2021 (odds ratio [OR]: 0.52; 95% confidence interval [CI]: 0.47–0.58 in 2020 and OR: 0.61; 95%CI: 0.56–0.66 in 2021; p < 0.05). In women with comorbidities, the death rate increased 1.7-fold (13.3 to 23.3%) and 1.4-fold (22.8 to 31.4%) in the obstetric and nonobstetric groups, respectively (OR: 0.52; 95%CI: 0.44–0.61 in 2020 to OR: 0.66; 95%CI: 0.59–0.73 in 2021; p < 0.05). In women without comorbidities, the mortality rate was higher for nonobstetric (2.4 times; 6.6 to 15.7%) than for obstetric women (1.8 times; 5.5 to 10.1%; OR: 0.81; 95%CI: 0.69–0.95 in 2020 and OR: 0.60; 95%CI: 0.58–0.68 in 2021; p < 0.05).

Conclusion There was an increase in maternal deaths from COVID-19 in 2021 compared with 2020, especially in patients with comorbidities. Death rates were even higher in nonpregnant women, with or without comorbidities.
Critical Care Nutrition Support following Cardiac Surgery in the Pediatric and Adult Population—A Review Article
Authors: Hote Milind Padmakar , Kapoor Poonam Malhotra , Malakar Jaydeep
Published: June 2022

Cardiac surgical patients in the intensive care unit certainly develop complex nutritional issues. Nutrition support is indicated in these subsets of patients and the same may be customized depending on individual patient characteristics. This review article that aims to examine the American Society for Parenteral and Enteral Nutrition guidelines for the use of parenteral and enteral nutrition in pediatric and adult cardiac surgical patients in cardiac critical care/intensive care unit evaluates the evidence related to the use of nutritional screening and nutritional assessment. The goal of this review is to enrich the discussion contained in the clinical guidelines and simplify the guideline statements to provide a platform for cardiac care providers to implement into their daily practice related to nutrition support in postoperative cardiac surgery patients.
Varied solutions to multicellularity: The biophysical and evolutionary consequences of diverse intercellular bonds
Authors: Day Thomas C. , Márquez-Zacarías Pedro , Bravo Pablo , Pokhrel Aawaz R. , MacGillivray Kathryn A. , Ratcliff William C. , Yunker Peter J.
Published: June 2022

The diversity of multicellular organisms is, in large part, due to the fact that multicellularity has independently evolved many times. Nonetheless, multicellular organisms all share a universal biophysical trait: cells are attached to each other. All mechanisms of cellular attachment belong to one of two broad classes; intercellular bonds are either reformable or they are not. Both classes of multicellular assembly are common in nature, having independently evolved dozens of times. In this review, we detail these varied mechanisms as they exist in multicellular organisms. We also discuss the evolutionary implications of different intercellular attachment mechanisms on nascent multicellular organisms. The type of intercellular bond present during early steps in the transition to multicellularity constrains future evolutionary and biophysical dynamics for the lineage, affecting the origin of multicellular life cycles, cell–cell communication, cellular differentiation, and multicellular morphogenesis. The types of intercellular bonds used by multicellular organisms may thus result in some of the most impactful historical constraints on the evolution of multicellularity.
Flow of two immiscible uniformly rotating couple stress fluid layers
Authors: Bashir Sammar , Sajid Muhammad
Published: June 2022

In this article, the flow of two uniformly rotating immiscible couple stress fluid layers is examined. In the upper layer, the flow has different velocity u1, density ρ1, viscosity ν1, couple stress viscosity γ1, and pressure p1, rotating with a constant angular velocity ω1 over another immiscible fluid layer with velocity u2, density ρ2, viscosity ν2, couple stress viscosity γ2, and pressure p2, rotating with a constant angular velocity ω2. The considered problem has a curious form, having characteristics of the famous von Karman and Bo¨dewadth flows of couple stress fluid below and above the interface, respectively. The flows are co-rotating at σ(=ω2/ω1)>0 and counter-rotating at σ<0, where σ is the ratio of angular velocities of the fluid layers. The lower layer would counter-rotate as compared to the upper layer. By utilizing similarity variables, the system of governing equations is transformed into an ordinary system. A finite-difference Keller–Box technique is applied to acquire the numerical results. For co-rotating flows (σ>0), the similarity solution exists for 0≤σ≤1, but for counter-rotating flows (σ<0), the solution exists up to some specific values of σ [i.e., σc(μ)≤σ≤1]. In the limiting cases, there are some similarities between the Bo¨dewadt problem (an outflow of fluid) and the upper layer flow and similarities between the von Karman problem (an inflow of fluid) and the lower-layer flow. The lower fluid layer shows a recirculation region of the flow near the interface, where the fluid cannot transfer.
Investigation of the structural, morphological, and magnetic properties of small crystalline Co–Cu ferrite nanoparticles in the single-domain regime
Authors: Alzoubi Gassem M. , Masadeh Ahmad S. , Shatnawi Moneeb T. M.
Published: June 2022

Single-domain Co0.5Cu0.5Fe2O4 ferrite nanoparticles with a crystallite size of 23 nm were hydrothermally prepared and characterized using x-ray diffraction, transmission electron microscopy, Fourier-transform infrared (FT-IR) spectroscopy, and vibrating sample magnetometry. According to the Rietveld refinement results, the prepared nanoparticles were single-phase with spinel type structures. The transmission electron microscope measurements demonstrated that the nanoparticles were spherical in shape. The FT-IR spectrum showed two principle absorption bands, confirming the characteristic features of cubic spinel ferrites. Magnetization data revealed that the prepared nanoparticles were ferrimagnetic from room temperature to 10 K, with well-defined saturation magnetization, coercivity, and remanence magnetization. The remanence magnetization and coercivity were found to increase with decreasing temperature. The value of room temperature squareness ratio (Mr/Ms) of 0.42 was found to be somewhat similar to that expected (0.5) for a system of noninteracting single-domain nanoparticles, suggesting that the prepared nanoparticles are in a single-domain regime. The temperature dependence of coercivity was found to have slight deviations from Kneller’s law, possibly due to interactions between nanoparticles. The zero field cooled–field cooled curves indicated that below 150 K, the nanoparticles were ferrimagnetic dressed with spin-glass behavior, resulting from interactions between the ferrimagnetic nanoparticles and/or random freezing of surface spins.
Investigation of a nanostructured GaP/MoS2 p-n heterojunction photodiode
Authors: Novák J. , Laurenčíková A. , Eliáš P. , Hasenöhrl S. , Sojková M. , Kováč J. , Kováč J.
Published: June 2022

We report on the properties of a GaP/MoS2 heterojunction prepared on a nanocone (NC)-structured GaP substrate and a planar GaP substrate. The nanocone-structured GaP substrate was prepared by the growth of GaP NCs at gold seeds on a ⟨111⟩B GaP substrate at 650 °C by metal organic vapor phase epitaxy. At this growth temperature, most NCs exhibited a hexagonal symmetry with six heavily facetted sides that contained numerous facets, ledges, and edges with a large surface area. A thin Mo layer was deposited on both types of GaP substrates by direct current magnetron sputtering. The Mo layer was then sulfurated at 700 °C and turned into a MoS2 layer. Electrical and optical characterization gave evidence that a PN heterojunction formed between GaP and MoS2 during the sulfuration process. The spectral response measurement showed two separate regions between 400 and 550 nm linked with the generation of carriers in GaP and between 550 and 1100 nm associated with the generation of carriers in the MoS2 layer. The planar GaP/MoS2 heterojunction generated a lower photocurrent compared with the GaP/MoS2 heterojunction that formed on the nanocone-structured GaP substrate. The results support theoretical assumptions that edge rich substrates can help to increase the quality of deposited 2D materials.
Extracting discrete hierarchies of Townsend's wall-attached eddies
Authors: Hu Ruifeng , Zheng Xiaojing , Dong Siwei
Published: June 2022

We decompose Townsend's wall-attached eddies from a multi-scale wall-bounded turbulent flow, extract discrete hierarchies of eddies, and study their geometrical characteristics. It is well known that the wall-attached eddies are hierarchical in nature and geometrically self-similar, but very few studies have successfully extracted them from a flow, especially from a decomposed flow. We propose a novel extraction scheme that is based on a spectral linear stochastic estimation methodology and the hierarchical nature of wall-attached eddies. The geometrical characteristics of the intense velocity clusters induced by attached eddies are studied via a clustering method. The extracted clusters are found to be self-similar in geometry that is consistent with Townsend's attached eddy hypothesis.
Interaction of shock and discontinuity waves at the stellar surfaces
Authors: Zeidan Dia , Pandey Manoj , Govekar Sweta
Published: June 2022

This paper will employ Lie's method to obtain a closed form solution of partial differential equations describing flow at the stellar surfaces. The solution obtained gives explicit expressions for the flow variables ahead and behind the shock; we were also able to provide expressions for shock velocity and path. The evolution of the discontinuity wave and its interaction with the shock wave have been discussed in detail. The interaction of the waves produces two reflected waves, whereas the shock acceleration experiences a jump. Explicit expressions are obtained for the amplitude of the reflected waves and the jump in the shock acceleration.
Transport properties of n-ethylene glycol aqueous solutions with focus on triethylene glycol–water
Authors: Santos C. I. A. V. , Barros M. C. F. , Ribeiro A. C. F. , Bou-Ali M. M. , Mialdun A. , Shevtsova V.
Published: June 2022

Soret effect and diffusion in triethylene glycol (TEG)–water mixtures were investigated as a function of concentration at 25 °C by means of optical digital interferometry, with the use of a classical Soret cell. Diffusion D, thermal diffusion DT, and Soret ST coefficients are described for the full concentration range and an analysis is made individually for TEG–water mixture and within a series of n-ethylene glycol (n-EG) aqueous systems. All coefficients decrease with increasing the concentration of TEG and n-EG. ST shows a change of sign with concentration, and this change is directly related to the ability of the n-EG molecule to establish hydrogen bonding with water. Diffusion and thermal diffusion coefficients present a plateau behavior with increasing concentration, showing the occurrence of changes in the preferential interactions in aqueous solution with concentration and meaning that, at high TEG composition, ether oxygens can be involved in the molecular interactions.
The spray distribution of a liquid jet in supersonic crossflow in the near-wall region
Authors: Li Fei , Wang Zhenguo , Li Peibo , Sun Mingbo , Wang Hongbo
Published: June 2022

The gas–liquid mixing process of a liquid jet in supersonic crossflow with a gas–liquid momentum ratio of 7.67 in the near-wall region is investigated numerically. The two-phase flow large eddy simulation is based on the Eulerian–Lagrangian approach and considers the droplet–wall interaction. The results indicate the penetration depth and the lateral extension width, which are in good agreement with the experimental data. The Ω shape, especially the spray foot structure of spray in the cross-sectional plane, is captured well. The transport process of spray toward the wall and the formation of spray foot are systematically studied. Under the influence of the upper CVP (counter-rotating vortex pair), partial droplets in the center region of the spray are transported to the near-wall region and move toward both sides when encountering the wall CVP. Under the current gas–liquid momentum ratio, droplets collide with the wall mainly in the central region at the bottom, which will produce splashed droplets. Affected by the horseshoe vortex, the instantaneous distribution of droplets on both sides near the wall shows stripes shape. The spray foot structure forms the shape that is narrow on the top and wide on the bottom and is mainly formed by splashed droplets. Some splashed droplets in the low-speed boundary layer constitute the lower half of the spray foot; meanwhile, some splashed droplets enter mainstream and constitute the upper half of the spray foot. Moreover, the spray is mainly distributed in the core region, and the spray concentration is very sparse in the spray foot region.
A spectral comparison of lightning discharge plasma and laser-induced air plasma
Authors: Cen Jianyong , Yang Cong , Yang Shulin , Li Zeguang , Zhang Jinjun
Published: June 2022

The high time-resolved spectrum of natural lightning is obtained by a slitless spectrograph. The spectrum of natural lightning is compared to the spectrum of laser-induced air plasma. The results show that the spectra of lightning and the spectra of laser-induced air plasma are similar, but they also have some differences. In the superimposed spectrum of lightning, the intensities of atomic lines are far stronger than those of ionic lines, and the continuous spectrum in the whole wavelength region is very strong. However, in the spectrum of laser-induced air plasma, the intensities of atomic lines are similar to those of ionic lines, and there is almost no continuous spectrum in the near-infrared region. In addition, the Hα line is strong in the lightning spectrum but very weak in the spectrum of laser-induced air plasma. The temperature, electron density, and conductivity are calculated, and their evolution with time is also given. The differences in the three physical parameters between lightning and laser-induced air plasma are analyzed. In addition, the reasons of spectral differences have been explained. These results will provide an important reference for the simulation of the lightning spectrum.
Opening Address
Authors: Davies Ian
Published: June 2022

As Australasia’s largest gathering of the oil and gas industry, APPEA 2022 opens with a powerhouse line-up of pre-eminent leaders setting the vision for the future. To view the video, click on the link to the right.
Integrative methods resolve taxonomy and relationships of snapping shrimps in the genus
Authors: Ashrafi Hossein , Hultgren Kristin M.
Published: June 2022

Extensive sampling around Martinique during the Muséum National d’Histoire Naturelle ‘Madibenthos’ expedition in 2016 resulted in a collection of hundreds of alpheid shrimps, of which 21 distinct species of Synalpheus Spence Bate, 1888 are studied herein. Combining results of a morphological analysis, a phylogenetic tree (combined 16S and COI) and species delimitation analyses (ABGD and PTP) indicates three species as new to science. These species are S. chaki sp. nov., S. corbariae sp. nov., and S. macdonaldi sp. nov. The first two new species belong to the S. rathbunae Coutière, 1909 species group, whereas the third new species broadly groups with the S. gambarelloides group. Additionally, 13 new country records of Synalpheus are reported for Martinique.
Infrared Nano-Imaging of Electronic Phase across the Metal–Insulator Transition of NdNiO3 Films
Authors: Liu Fanwei , Huang Sisi , Chen Sidan , Chen Xinzhong , Liu Mengkun , Jin Kuijuan , Chen Xi
Published: June 2022

NdNiO3 is a typical correlated material with temperature-driven metal–insulator transition. Resolving the local electronic phase is crucial in understanding the driving mechanism behind the phase transition. Here we present a nano-infrared study of the metal–insulator transition in NdNiO3 films by a cryogenic scanning near-field optical microscope. The NdNiO3 films undergo a continuous transition without phase coexistence. The nano-infrared signal shows significant temperature dependence and a hysteresis loop. Stripe-like modulation of the optical conductivity is formed in the films and can be attributed to the epitaxial strain. These results provide valuable evidence to understand the coupled electronic and structural transformations in NdNiO3 films at the nano-scale.
Continuous-wave and pulsed operation of Ho:YLF laser end-pumped by Tm:fiber laser
Authors: Babaiy Tooski Majid , Maleki Abbas , Eslami Majd Abdolah , Ebadian Hassan
Published: June 2022

Continuous-wave and pulsed operation of a Ho:YLF laser was demonstrated. A Tm:fiber laser with 70 W output power was used for the pump source. In this experimental setup, the end-pumped gain medium with 0.5% and 1% Ho concentration in the optical resonators were used. In the continuous-wave regime, 14.2 and 12.8 W linearly polarized power with a concave-concave resonator for 1.0% and 0.5% Ho dopes were extracted, respectively. These amounts correspond to slope efficiencies of 51.9% and 71.3% and optical-to-optical efficiencies of 39.4% and 54.7% for absorbed pump power, respectively. To avoid optical damage, a U-shaped concave-concave resonator was installed, and the resulting spot size in the resonator was about 1.31 mm. The spot size changes about 10% along the total physical length of the resonator. In the pulsed operation regime, for 0.5% Ho concentration with 20 ms pump pulse duration and 10 Hz repetition rates, the free-running output energy was 172 mJ with 16 ms pulse duration. In addition, the absorbed pump energy was about 485 mJ, corresponding to the slope and the optical-to-optical efficiencies of 14.8% and 12.3%, respectively. Also, 27 mJ pulse energy with 29.7 ns duration was achieved for Q-switched operation. Finally, the angle of output beam divergence was measured at approximately 1.1 mrad, and the laser emission wavelength was 2.0568 µm with 0.0065 µm line width.
A New Statistical Distance Scale for Planetary Nebulae, Based on Gaia EDR3
Authors: Ali A. , Algarni E. , Mindil A. , Alghamdi S. A
Published: June 2022

The present work aims to build a new statistical distance scale for planetary nebulae (PNe) based on a rigorous calibration sample. The distances of the calibration sample are derived from the trigonometric parallax method using the recent measurements of Gaia Early Data Release 3 (Gaia EDR3). The new distance scale is created by applying the well-known linear relationship between the radio surface brightness temperature and the nebular radius. The calibration sample is made up of 96 PNe of accurately computed distances with uncertainties less than 20%. Earlier ground- and space-based trigonometric parallaxes of PNe display inconsistency with those of Gaia, particularly the Hipparcos results. In addition, these measurements have appreciably lower precision than those of Gaia. When compared to the trigonometric technique, the expansion and kinematic methods exhibited more consistency than the spectroscopic, extinction, gravity, and photoionization methods. Furthermore, contrary to earlier results in the literature, the extinction and gravity methods, on average, underestimate and slightly overestimate the PN distances respectively. As a byproduct of extracting the Gaia parallaxes, we detect the radial velocity and variability for 14 and 3 PN central stars (CSs), respectively. To our knowledge, the variability of Hen 2-447 CS has been determined for the first time.
Enabling adaptive pedestals in predictive transport simulations using neural networks
Authors: Gillgren A. , Fransson E. , Yadykin D. , Frassinetti L. , Strand P. , JET Contributors
Published: June 2022

We present PEdestal Neural Network (PENN) as a machine learning model for tokamak pedestal predictions. Here, the model is trained using the EUROfusion JET pedestal database to predict the electron pedestal temperature and density from a set of global engineering and plasma parameters. Results show that PENN makes accurate predictions on the test set of the database, with R
2 = 0.93 for the temperature, and R
2 = 0.91 for the density. To demonstrate the applicability of the model, PENN is employed in the European transport simulator (ETS) to provide boundary conditions for the core of the plasma. In a case example in the ETS with varied neutral beam injection (NBI) power, results show that the model is consistent with previous studies regarding NBI power dependency on the pedestal. Additionally, we show how an uncertainty estimation method can be used to interpret the reliability of the predictions. Future work includes further analysis of how pedestal models, such as PENN, or other advanced deep learning models, can be more efficiently implemented in integrating modeling frameworks, and also how similar models may be generalized with respect to other tokamaks and future device scenarios.
Microscopic density-functional approach to nonlinear elasticity theory
Authors: Haussmann Rudolf
Published: June 2022

Starting from a general classical model of many interacting particles we present a well defined step by step procedure to derive the continuum-mechanics equations of nonlinear elasticity theory with fluctuations which describe the macroscopic phenomena of a solid crystal. As the relevant variables we specify the coarse-grained densities of the conserved quantities and a properly defined displacement field which describes the local translations, rotations, and deformations. In order to stay within the framework of the conventional density-functional theory we first and mainly consider the isothermal case and omit the effects of heat transport and warming by friction where later we extend our theory to the general case and include these effects. We proceed in two steps. First, we apply the concept of local thermodynamic equilibrium and minimize the free energy functional under the constraints that the macroscopic relevant variables are fixed. As results we obtain the local free energy density and we derive explicit formulas for the elastic constants which are exact within the framework of density-functional theory. Second, we apply the methods of nonequilibrium statistical mechanics with projection-operator techniques. We extend the projection operators in order to include the effects of coarse-graining and the displacement field. As a result we obtain the time-evolution equations for the relevant variables with three kinds of terms on the right-hand sides: reversible, dissipative, and fluctuating terms. We find explicit formulas for the transport coefficients which are exact in the limit of continuum mechanics if the projection operators are properly defined. By construction the theory allows the diffusion of particles in terms of point defects where, however, in a normal crystal this diffusion is suppressed.
Study on a micro radiation probe with high SNR based on CdZnTe detector
Authors: Xiaoyu X. , Lian C. , Weiwei Q. , Ge J.
Published: June 2022

In this paper, we develop a micro radiation probe with a
CdZnTe detector. To obtain a high signal-to-noise ratio(SNR)
performance, circuit simulation and analysis were performed before
circuit design, to evaluate the signal characters and frequency
response of the electronic design. We adopted a method to evaluate
the electronic noise level of specific readout circuits design and
determined a better timing parameter of the shaping circuit. Our
results confirmed that using a proper design of charge sensitive
amplifier(CSA) circuit and the filter system on the readout circuit
improved the energy resolution of the probe. Energy spectrum
measurement using a 137Cs source showed that the energy
resolution of 662 keV γ-ray can reach 2.6%. This enables
this microprobe for multi-nuclides recognition or nuclides to
monitor in nuclear medicine applications.