bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes and Complications Associated with Acute Gunshot Fractures in Cats and Dogs
Authors: Schrock Kelly , Kerwin Sharon C. , Jeffery Nick
Published: December 2021

Objective The aim of this study was to summarize outcomes and complications of gunshot fracture management in small animals.

Study Design Review of cats and dogs with radiographically confirmed acute gunshot fractures, presenting data on signalment, fracture location, fracture management (surgical vs. non-surgical, type of surgical repair), fracture comminution, extent of soft tissue trauma, postoperative complication and overall outcome. A poor outcome was defined as patient death, major postoperative complication or limb amputation (both as primary treatment or secondary to postoperative complications).

Results Ninety-seven animals with 137 acute gunshot-induced fractures were identified. There were 21 (15.3%) maxillofacial, 16 (11.7%) vertebral column, 8 (5.8%) rib, 56 (40.9%) distal long bone (below stifle/cubital joint) and 36 (26.3%) proximal long bone (at or above stifle/cubital joint) fractures. Overall, 20/37 cases with sufficient follow-up details incurred a poor fracture outcome. Extensive soft tissue trauma at the fracture site was associated with an increased likelihood of poor outcome. The most common poor outcomes were primary limb amputations (7 cases) and postoperative complications (3 osteomyelitis/surgical site infections, 4 delayed/non-unions).

Conclusion Gunshot fractures overall have high likelihood of poor outcome. Severe soft tissue injury is associated with complications. Mitigating poor outcome likely requires early aggressive wound management.
Does MRI Knee in Those over 50 Years with Knee Pain in Osteoarthritis Alter Management? A Retrospective Review
Authors: Murphy Alexandra N. , Yelverton Bryan , Clesham Kevin , Hassell Kathy , Kavanagh Eoin , Eustace Stephen , Cashman James
Published: December 2021

Knee osteoarthritis (OA) is a significant cause of pain and disability worldwide. Imaging provides diagnosis, prognostication, and follow-up. Radiographs are first line, useful, and inexpensive. Magnetic resonance imaging (MRI) can detect additional features not seen on radiograph, but it is of questionable usefulness in the management of knee OA. Our aim was to investigate the usefulness of MRI in the workup of knee OA and whether MRI alters management in knee OA. A retrospective review was performed of consecutive MRI knees performed for knee pain in those over 50 years. Clinical information and documentation of management plan pre- and post-MRI were collected. Assessment was made whether the MRI results influenced the final management plan. Of the 222 MRI knees included for study, the majority (62.2%) had not had a recent radiograph. OA was reported in 86.9% of radiographs and 89.6% of MRI. On MRI, the most prevalent finding was tearing/abnormality of the medial meniscus, seen in 47% of MRIs overall, increasing to all in severe OA. MRI assisted with management in 9.5% of all (21/222) patients, and changed management plans in 23% of those that had documented management plans prior to the MRI (6/26 patients). MRIs can guide tailored management in knee OA and are useful for surgical planning; however, they should only be ordered in certain cases, and a radiograph should always be performed first. MRI should be considered if symptoms are not explained by OA alone or the appropriate treatment option requires MRI.
The Utility of Perioperative Products for the Prevention of Surgical Site Infections in Total Knee Arthroplasty and Lower Extremity Arthroplasty: A Systematic Review
Authors: Salem Hytham S. , Sherman Alain E. , Chen Zhongming , Scuderi Giles R. , Mont Michael A.
Published: December 2021

Surgical site infections (SSIs) are among the most prevalent and devastating complications following lower extremity total joint arthroplasty (TJA). Strategies to reduce the rates can be divided into preoperative, perioperatives, and postoperative measures. A multicenter trial is underway to evaluate the efficacy of implementing a bundled care program for SSI prevention in lower extremity TJA including: (1) nasal decolonization; (2) surgical skin antisepsis; (3) antimicrobial incise draping; (4) temperature management; and (5) negative-pressure wound therapy for selected high-risk patients. The purposes of this systematic review were to provide a background and then to summarize the available evidence pertaining to each of these SSI-reduction strategies with special emphasis on total knee arthroplasty. A systematic review of the literature was conducted in accordance with the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines. Five individual literature searches were performed to identify studies evaluating nasal decolonization temperature management, surgical skin antisepsis, antimicrobial incise draping, and negative-pressure wound therapy. The highest level of evidence reports was used in each product review, and if there were insufficient arthroplasty papers on the particular topic, then papers were further culled from the surgical specialties to form the basis for the review. There was sufficient literature to assess all of the various prophylactic and preventative techniques. All five products used in the bundled program were supported for use as prophylactic agents or for the direct reduction of SSIs in both level I and II studies. This systematic review showed that various pre-, intra-, and postoperative strategies are efficacious in decreasing the risks of SSIs following lower extremity TJA procedures. Thus, including them in the armamentarium for SSI-reduction strategies for hip and knee arthroplasty surgeons should decrease the incidence of infections. We expect that the combined use of these products in an upcoming study will support these findings and may further enhance the reduction of total knee arthroplasty SSIs in a synergistic manner.
Parents' Experiences Caring for a Child after a Critical Illness: A Qualitative Study
Authors: Olson Lenora M. , Perry Grace N. , Yang Serena , Galyean Patrick O'Roke , Zickmund Susan L. , Sorenson Samuel , Pinto Neethi P. , Maddux Aline B. , Watson R. Scott , Fink Ericka L.
Published: December 2021

Objectives This article described parents' experience and identifies outcomes important to parents following their child's critical illness.

Methods Semistructured interviews with 22 female and 4 male parents representing 26 critically ill children with predominately neurologic and respiratory diagnoses. Most children were younger than 5 years at discharge with a median (interquartile range) of 2 (2.0–3.0) years from discharge to interview.

Results Many children returned home with life-altering physical and cognitive disabilities requiring months to years of rehabilitation. Parents remembered feeling unprepared and facing an intense, chaotic time when the child first returned home. They described how they suddenly had to center their daily activities around the child's needs amidst competing needs of siblings and partners, and in some cases, the medicalization of the home. They recounted negotiating adjustments almost daily with insurance agencies, medical doctors and therapists, employers, the child, and other family members to keep the family functioning. In the long term, families developed a new norm, choosing to focus on what the child could still do rather than what they could not. Even if the child returned to baseline, parents remembered the adjustments made to keep the child alive and the family functioning.

Conclusion Heightened awareness of family experiences after pediatric critical illness will allow health care providers to improve family preparedness for the transition from hospital to home.
Outcome and Risk Factors of Febrile Episodes Treated with Broad Spectrum Antibiotics and Polyclonal IgM–Enriched Immunoglobulin in Pediatric Oncology Hematology Patients: A Retrospective Study
Authors: Abram Nicoletta , Baretta Valentina , Mercolini Federico , De Bortoli Massimiliano , Chinello Matteo , Balter Rita , Bonetti Elisa , Zaccaron Ada , Vitale Virginia , Caddeo Giulia , Mauro Margherita , Battisti Laura , Tridello Gloria , Cesaro Simone
Published: December 2021

Objective Preparations with high-titer immunoglobulin-M (HT-IgM) have been used to treat neonatal and adult sepsis as adjuvant to antibiotics. Limited data are available of this use in pediatric oncohematological patients. We retrospectively assessed the characteristics and outcome of febrile episodes treated with broad-spectrum antibiotics and HT-IgM.

Methods This study included febrile episodes diagnosed after chemotherapy or hematopoietic stem cell transplantation (HSCT) treated with antibiotics and HT-IgM. Study period was from January 2011 to March 2019.

Results Seventy febrile episodes in 63 patients were eligible. In 40% of episodes (n = 28), blood cultures identified a causative organism: Gram-negative (n = 15), Gram-positive (n = 8), polybacterial (n = 4), fungi (n = 1). Twenty-six percent of Gram-negatives were extend spectrum β-lactamase (ESBL)-producers. In 44% of episodes, a deep-organ localization was present, mostly pulmonary. Severe or profound neutropenia, hypotension, and hypoxemia were present in 89, 26, and 21% of episodes, respectively; 20% of episodes required intensive care and 20% of episodes required the use of inotropes. Overall, 90-day mortality was 13% and infection-attributable mortality resulted 8.6%. More than half of the patients received HT-IgM within 24 hours from fever onset. HT-IgM-related allergic reactions occurred in three episodes. Risk factors for 90-day mortality were as follows: hypotension and hypoxemia at fever presentation, admission to intensive care unit (ICU), use of inotropes, presence of deep-organ infection, and escalation of antibiotic therapy within 5 days.

Conclusion The combination of broad-spectrum antibiotics and HT-IgM was feasible, tolerated, and promising, being associated with a limited infectious mortality. Further prospective controlled studies are needed to assess the efficacy of this combination over a standard antibiotic approach.
Detailed characterization of a laboratory magnetized supercritical collisionless shock and of the associated proton energization
Authors: Yao W. , Fazzini A. , Chen S. N. , Burdonov K. , Antici P. , Béard J. , Bolaños S. , Ciardi A. , Diab R. , Filippov E. D. , Kisyov S. , Lelasseux V. , Miceli M. , Moreno Q. , Nastasa V. , Orlando S. , Pikuz S. , Popescu D. C. , Revet G. , Ribeyre X. , d’Humières E. , Fuchs J.
Published: December 2021

Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation. In the absence of particle collisions in the system, theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure (as in our case) is able to induce energy dissipation and allow shock formation. Shock formation can alternatively take place when two plasmas interact, through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation. Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers (JLF/Titan at LLNL and LULI2000) with high-strength magnetic fields, we have investigated the generation of a magnetized collisionless shock and the associated particle energization. We have characterized the shock as being collisionless and supercritical. We report here on measurements of the plasma density and temperature, the electromagnetic field structures, and the particle energization in the experiments, under various conditions of ambient plasma and magnetic field. We have also modeled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations. As a companion paper to Yao et al. [Nat. Phys. 17, 1177–1182 (2021)], here we show additional results of the experiments and simulations, providing more information to allow their reproduction and to demonstrate the robustness of our interpretation of the proton energization mechanism as being shock surfing acceleration.
Graph neural networks for laminar flow prediction around random two-dimensional shapes
Authors: Chen J. , Hachem E. , Viquerat J.
Published: December 2021

In recent years, the domain of fast flow field prediction has been vastly dominated by pixel-based convolutional neural networks. Yet, the recent advent of graph convolutional neural networks (GCNNs) has attracted considerable attention in the computational fluid dynamics (CFD) community. In this contribution, we proposed a GCNN structure as a surrogate model for laminar flow prediction around two-dimensional (2D) obstacles. Unlike traditional convolution on image pixels, the graph convolution can be directly applied on body-fitted triangular meshes, hence yielding an easy coupling with CFD solvers. The proposed GCNN model is trained over a dataset composed of CFD-computed laminar flows around 2000 random 2D shapes. Accuracy levels are assessed on reconstructed velocity and pressure fields around out-of-training obstacles and are compared with that of standard U-net architectures, especially in the boundary layer area.
Grad's distribution functions-based gas kinetic scheme for simulation of flows beyond Navier–Stokes level
Authors: Yuan Z. Y. , Shu C. , Liu Z. J.
Published: December 2021

Conventional gas kinetic scheme (GKS) has been successfully utilized to obtain the accurate solution of Navier–Stokes (NS) equations. However, when it comes to flows beyond NS level, the conventional GKS is not reliable because its initial gas distribution function is approximated by the first-order Chapman–Enskog expansion, which merely recovers the NS equations. In order to make an extension for flows beyond NS level, we propose the Grad's distribution functions-based GKS in this paper. This scheme retains the advantage of conventional GKS and constructs the numerical fluxes through a time-dependent gas distribution function, which is derived from the integral solution of Boltzmann equation. In the present scheme, the initial gas distribution function in the local solution of Boltzmann equation is approximated by Grad's 13 and 26 distribution functions. Furthermore, the high-order moments in the initial Grad's distribution function are calculated by moment relationship directly, and thus, the solution of complicated partial differential equations for these high-order moments is avoided. Four benchmark numerical examples are tested to validate the performance of the present scheme, and the results demonstrate that the present scheme can not only recover NS solutions in the continuum region but also predict reasonable results for flows in the slip and transition regimes.
Drag and wake structure of a quasi-dandelion pappus model at low and moderate Reynolds numbers: The effects of filament width
Authors: Li Shiqing , Pan Dingyi , Li Jun , Shao Xueming
Published: December 2021

The aerodynamic performance and wake structure of dandelion seed pappus have been numerically studied based on a simplified quasi-dandelion pappus (QDP) model with its filaments represented by rectangular cylinders. The filament width is chosen as the major geometric parameter for investigation. A rigorous measuring strategy is developed for the identification of the recirculation region width in the wake of the QDP model. Three regimes are distinguished as the filament width increases, i.e., a dandelion-like regime, a transition regime, and a disk-like regime. In the dandelion-like regime, the recirculation region widths are relatively large and monotonously decrease with the increase in Reynolds number. In the transition regime, the recirculation region widths are moderate and first decrease sharply at low Reynolds number and subsequently maintain an approximately invariant value. In the disk-like regime, the recirculation region widths are relatively small. The Reynolds number based on the recirculation region width is defined, and its correlation to the drag coefficient in a different regime is also discussed. In addition, as the QDP model turns from the dandelion-like regime to the disk-like regime, the pressure distribution in the wake turns from the recirculation region type to the flow stagnation type. The current study may provide a reference for the design of more efficient dandelion-like aircraft.
Single photon generation from AlGaN exciton localization centers exhibiting narrow spectral linewidths
Authors: Arita Munetaka , Iki Taichi , Holmes Mark J. , Arakawa Yasuhiko
Published: December 2021

We report the discovery and characterization of single-photon-emitting carrier localization centers that are spontaneously formed along misfit dislocations in AlGaN. The emitters exhibit extremely narrow linewidths, which are in some cases narrower than our resolution limit of 35 µeV. Spectral analysis reveals a record-low inhomogeneous broadening (smaller than 20 µeV), which can be characterized as almost spectral-diffusion free. Such narrow linewidths allow for an unprecedented discussion of the homogeneous linewidths of quantum emitters in the III-nitrides and, in the current case, provide a lower bound on the pure-dephasing time T2 of ∼200 ps. These experimental results will pave the way to further improve the performance of III-nitride low-dimensional nanostructure-based quantum emitters.
Variability and trend of sea level in southern waters of Java, Indonesia
Authors: Nurlatifah Amalia , Martono  , Susanti Indah , Suhermat Mamat
Published: December 2021

The coastal area of Java has become a centre of new economic growth. The southern coast of Java, which is directly adjacent to the tropical Indian Ocean, is very vulnerable to sea level rise caused by climate change. Information on variability and trends in sea level are therefore very important for adaptation and disaster mitigation efforts. This research was conducted to determine the variability and trend of sea level in the southern sea of Java. Data used were from satellite altimeter from 1993 to 2018 and tide gauges from 2007 to 2015. The rate of sea level rise was analysed using linear regression. The results showed that the sea level variability in the southern waters of Java was influenced by the Asian–Australian monsoon, eddy currents and the Indian Ocean Dipole (IOD). During June–November, there was a very significant decrease in sea level, especially in the south of East Java and Central Java, which was caused by upwelling and eddy currents. When there was a positive phase of IOD and an El Niño event, sea level decreased; conversely, when the IOD was in a negative phase, sea level increased. For the period 1993–2018, the sea level in the southern waters of Java increased by about 4.7 mm/year.
Modelling chamise fuel moisture content across California: a machine learning approach
Authors: Capps Scott B. , Zhuang Wei , Liu Rui , Rolinski Tom , Qu Xin
Published: December 2021

Live fuel moisture content plays a significant and complex role in wildfire propagation. However, in situ historical and near real-time live fuel moisture measurements are temporally and spatially sparse within wildfire-prone regions. Routine bi-weekly sampling intervals are sometimes exceeded if the weather is unfavourable and/or field personnel are unavailable. To fill these spatial and temporal gaps, we have developed a daily gridded chamise (Adenostoma fasciculatum) live fuel moisture product that can be used, in conjunction with other predictors, to assess current and historical wildfire danger/behaviour. Chamise observations for 52 new- and 41 old-growth California sites from the National Fuel Moisture Database were statistically related to dynamically downscaled high-resolution weather predictors using a random forest machine learning model. This model captures reasonably well the temporal and spatial variability of chamise live fuel moisture content within California. Compared with observations, model-predicted live fuel moisture values have an overall R2, root mean squared error (RMSE) and bias of 0.79, 15.34% and 0.26%, respectively, for new growth and 0.63, 8.81% and 0.11% for old growth. Given the success of the model, we have begun to use it to produce daily forecasts of chamise live fuel moisture content for California utilities.
Roles and experiences of non-governmental organisations in wildfire response and recovery
Authors: Miller Rebecca K. , Mach Katharine J.
Published: December 2021

Local non-governmental organisations (NGOs) play critical roles in providing immediate relief resources and long-term recovery support for communities after a disaster. Drawing on interviews with NGO representatives involved in three Northern California wildfires in 2017 and 2018, this study identifies challenges and opportunities for NGOs supporting wildfire relief and recovery. Across fires and NGOs, NGO management and wellbeing, coordination and disaster experiences emerge as common barriers and enablers of relief and recovery. In many cases, local NGOs’ participation in wildfire relief and recovery included simultaneous expansion of an organisation’s mission and activities and negative impacts on staff mental health. Under the rapidly evolving circumstances of relief and the prolonged burdens of recovery, personal relationships across NGOs and government agencies significantly improved coordination of assistance to communities. Finally, interviewees expressed greater confidence when responding to wildfires if they had previous experience with a disaster, although the COVID-19 pandemic presented distinct challenges on top of pre-existing long-term recovery work. Despite repeated assertions that interviewees’ experiences reflected only their individual community or wildfire, key challenges and opportunities were consistent across disasters. These results may aid other NGOs in preparing to provide immediate disaster relief and long-term recovery in California and other wildfire-prone areas.
Perception of structurally distinct effectors by the integrated WRKY domain of a plant immune receptor
Authors: Mukhi Nitika , Brown Hannah , Gorenkin Danylo , Ding Pingtao , Bentham Adam R. , Stevenson Clare E. M. , Jones Jonathan D. G. , Banfield Mark J.
Published: December 2021

Significance

This study reveals a mechanism for effector perception by a plant NLR immune receptor that contains an integrated domain (ID) that mimics an authentic effector target. The
Arabidopsis
immune receptors RRS1 and RPS4 detect the
Pseudomonas syringae
pv.
pisi
secreted effector AvrRps4 via a WRKY ID in RRS1. We used structural biology to reveal the mechanisms of AvrRps4
C
–WRKY interaction and demonstrated that this binding is essential for effector recognition in planta. Our analysis revealed features of the WRKY ID that mediate perception of structurally distinct effectors from different bacterial pathogens. These insights could enable engineering NLRs with novel recognition specificities, and enhance our understanding of how effectors interact with host proteins to promote virulence.
A higher-multipole gravitational waveform model for an eccentric binary black holes based on the effective-one-body-numerical-relativity formalism
Authors: Liu Xiaolin , Cao Zhoujian , Zhu Zong-Hong
Published: December 2021

We have previously constructed a waveform model,

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waveform model in the following three respects. Firstly, we update the EOB dynamics from

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to

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waveform model, we call our new waveform model

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. The (l, |m|) = (2, 2) mode waveform of

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can fit the original

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waveform very well in the case of a quasi-circular orbit. We have validated

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waveform model through comparing the waveform against the Simulating eXtreme Spacetimes (SXS) catalog. The comparison is done for BBH with total mass in (20, 200)M
⊙ using Advanced LIGO designed sensitivity. For the quasi-circular cases we have compared our (2, 2) mode waveforms to the 281 numerical relativity (NR) simulations of BBH along quasi-circular orbits. All of the matching factors are bigger than 98%. For the elliptical cases, 24 NR simulations of BBH along an elliptic orbit are used. For each elliptical BBH system, we compare our modeled gravitational polarizations against the NR results for different combinations of the inclination angle, the initial orbit phase and the source localization in the sky. We use the minimal matching factor respect to the inclination angle, the initial orbit phase and the source localization to quantify the performance of the higher modes waveform. We found that after introducing the higher modes, the minimum of the minimal matching factor among the 24 tested elliptical BBHs increases from 90% to 98%. Our

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waveform model can match all tested 305 SXS waveforms better than 98% including highly spinning (χ = 0.99) BBH, highly eccentric (e ≈ 0.6 at reference frequency Mf
0 = 0.002) BBH and large mass ratio (q = 10) BBH.
Degradation of benzene, toluene, and xylene with high gaseous hourly space velocity by double dielectric barrier discharge combined with Mn3O4/activated carbon fibers
Authors: Liu Xin , Liu Jianqi , Chen Jiayao , Zhong Fangchuan
Published: December 2021

A novel strategy for the degradation of high gaseous hourly space velocity benzene, toluene, and xylene (BTX) by double dielectric barrier discharge (DDBD) coupled with Mn3O4/ activated carbon fiber (ACF) catalysts was proposed in this work. A series of Mn3O4/ACF catalysts were synthesized using the hydrothermal method and characterized. The results showed that all the prepared catalysts could improve the degradation of BTX in the DDBD system and inhibit the production of ozone. Among the catalysts with different Mn loading, the 5.6%Mn3O4/ACF, with the highest Mn(+3) content (43.2%) and the highest absorbed oxygen content (38.5%), presented the best catalytic performance. In the 5.6% Mn3O4/ACF + DDBD system, the degradation efficiency of benzene, toluene and xylene could reach 49.9%, 79.7% and 97.1%, respectively, with a specific input energy of 400 J l−1. The carbon balance and CO2 selectivity, meanwhile, were 83.3% and 51.1%, respectively. It seemed that Mn(+3) and absorbed oxygen content could be a reference for the catalytic performance of Mn3O4/ACF catalysts. The higher the Mn (III) and absorbed oxygen, the better the catalytic performance of the Mn3O4/ACF catalysts. The organic by-products were identified by chromatography-mass spectrometry, and a possible reaction mechanism of BTX in the DDBD reactor and catalyst surface was proposed based on the composition of organic by-products.
Multi-temperature generalized Zhdanov closure for scrape-off layer/edge applications
Authors: Raghunathan M , Marandet Y , Bufferand H , Ciraolo G , Ghendrih Ph , Tamain P , Serre E
Published: December 2021

The derivation of the multi-temperature generalized Zhdanov closure is provided, starting from the most general form of the left-hand side of the moment-averaged kinetic equation with the Sonine–Hermite polynomial ansatz for an arbitrary number of moments. The process of arriving at the reduced higher-order moment equations, with its assumptions and approximations, is explicitly outlined. The generalized multi-species multi-temperature coefficients from our previous article are used to compute values of higher-order moments such as heat flux in terms of the lower-order moments. Transport coefficients and the friction and thermal forces for magnetic confinement fusion relevant cases with the generalized coefficients are compared to the scheme with the single-temperature coefficients previously provided by Zhdanov et al. It is found that the 21 N-moment multi-temperature coefficients are adequate for most cases relevant to fusion. Furthermore, the 21 N-moment scheme is also tested against the trace approximation to determine the range of validity of the trace approximation with respect to fusion-relevant plasmas. Possible refinements to the closure scheme are also illustrated to account for quantities which might be significant in certain schemes, such as the drift approximation.
Plasma and electrical characteristics depending on an antenna position in an inductively coupled plasma with a passive resonant antenna
Authors: Kim Ju Ho , Chung Chin-Wook
Published: December 2021

We investigated the plasma and electrical characteristics depending on the antenna position in an inductively coupled plasma with a passive resonant antenna. When the powered antenna and passive resonant antenna are installed near the top plate and in the middle of the cylindrical reactor (setup A), respectively, the ion density at the resonance is about 2.4 times to 9 times higher than that at non-resonance. This is explained by the reduction in power loss in the powered antenna (including the matching circuits) and the increase in power absorbed by the plasma discharge. However, when the powered antenna and passive resonant antenna are interchanged (setup B), the ion density at the resonance is not significantly different from that at the non-resonance. When RF power is changed from 50 to 200 W, the ion density at the resonance of setup B is 1.6 times to 5.4 times higher than at the non-resonance of setup A. To analyse this difference, the profile of the z-axis ion density is measured and the electric and magnetic field simulations are investigated. The results are discussed along with the electron kinetics effect and the coupling loss between the antenna and the metal plate.
Characterizing the transduction behavior of ionic polymer-metal composite actuators and sensors via dimensional analysis
Authors: Olsen Zakai J , Kim Kwang J
Published: December 2021

Ionic polymer-metal composites (IPMCs) are functional smart materials that exhibit both electromechanical and mechanoelectrical transduction properties, and the physical phenomenon underlying the transduction mechanisms have been studied across the literature extensively. Here we use a new modeling framework to conduct the most comprehensive dimensional analysis of IPMC transduction phenomena, characterizing the IPMC actuator displacement, actuator blocking force, short-circuit sensing current, and open-circuit sensing voltage under static and dynamic loading. The information obtained in this analysis is used to construct nonlinear regression models for the transduction response as univariant and multivariant functions. Automatic differentiation techniques are leveraged to linearize the nonlinear regression models in the vicinity of a typical IPMC description and derive the sensitivity of the transduction response with respect to the driving independent variables. Further, the multiphysics model is validated using experimental data collected for the dynamic IPMC actuator and voltage sensor. With data collected from physical samples of IPMC materials in-lab, the regression models developed under the new computational framework are verified.
Enhancement of high temperature thermoelectric performance of cobaltite based materials for automotive exhaust thermoelectric generators
Authors: Bayata Fatma
Published: December 2021

Thermoelectric (TE) generators can directly convert exhaust waste heat into electricity in vehicles. However, the low conversion efficiency of TE generators is the main obstacle to their commercialization in automotive. Their efficiency mainly depends on the performance of the used materials which is quantified by the figure of merit (ZT value). In the present study, single- and co-doped calcium cobaltites (CCO) with rare-earth (Tb) and transition metals (Cu, Fe, Ni, Mn, Cr) were produced using sol–gel technique in order to improve their high temperature TE properties for heat recovery in exhaust manifold applications. By the combined effect of doping approach and the production technique used in this study, a remarkable decrease in the grain size of CCO was obtained, and thus its thermal conductivity dramatically decreased. Besides, thermopower values were improved significantly. The reduction in thermal conductivity and the increase in thermopower led to an enhancement in ZT value of CCO ceramics. Among all the co-doped samples, Tb–Cu co-doped CCO displayed the maximum ZT value of 0.116 at 873 K which is 2.5 times larger than that of pure CCO. The high thermal stability and the enhanced TE performance make Tb–Cu co-doped CCO material a potential candidate for heat recovery in automotive exhaust TE generators.
Efficient light harvesting and photon sensing via engineered cooperative effects
Authors: Mattiotti Francesco , Sarovar Mohan , Giusteri Giulio G , Borgonovi Fausto , Celardo G Luca
Published: December 2021

Efficient devices for light harvesting and photon sensing are fundamental building blocks of basic energy science and many essential technologies. Recent efforts have turned to biomimicry to design the next generation of light-capturing devices, partially fueled by an appreciation of the fantastic efficiency of the initial stages of natural photosynthetic systems at capturing photons. In such systems extended excitonic states are thought to play a fundamental functional role, inducing cooperative coherent effects, such as superabsorption of light and supertransfer of photoexcitations. Inspired by this observation, we design an artificial light-harvesting and photodetection device that maximally harnesses cooperative effects to enhance efficiency. The design relies on separating absorption and transfer processes (energetically and spatially) in order to overcome the fundamental obstacle to exploiting cooperative effects to enhance light capture: the enhanced emission processes that accompany superabsorption. This engineered separation of processes greatly improves the efficiency and the scalability of the system.
Quantum mechanical solution to spectral lineshape in strongly-coupled atom–nanocavity system
Authors: Zeng Jian , Li Zhi-Yuan
Published: December 2021

The strongly coupled system composed of atoms, molecules, molecule aggregates, and semiconductor quantum dots embedded within an optical microcavity/nanocavity with high quality factor and/or low modal volume has become an excellent platform to study cavity quantum electrodynamics (CQED), where a prominent quantum effect called Rabi splitting can occur due to strong interaction of cavity-mode single-photon with the two-level atomic states. In this paper, we build a new quantum model that can describe the optical response of the strongly-coupled system under the action of an external probing light and the spectral lineshape. We take the Hamiltonian for the strongly-coupled photon–atom system as the unperturbed Hamiltonian
H

0 and the interaction Hamiltonian of the probe light upon the coupled-system quantum states as the perturbed Hamiltonian
V
. The theory yields a double Lorentzian lineshape for the permittivity function, which agrees well with experimental observation of Rabi splitting in terms of spectral splitting. This quantum theory will pave the way to construct a complete understanding for the microscopic strongly-coupled system that will become an important element for quantum information processing, nano-optical integrated circuits, and polariton chemistry.
Nonlocal nonreciprocal optomechanical circulator
Authors: Zheng Ji-Hui , Peng Rui , Cheng Jiong , An Jing , Zhang Wen-Zhao
Published: December 2021

A nonlocal circulator protocol is proposed in a hybrid optomechanical system. By analogy with quantum communication, using the input–output relationship, we establish the quantum channel between two optical modes with long-range. The three-body nonlocal interaction between the cavity and the two oscillators is obtained by eliminating the optomechanical cavity mode and verifying the Bell-CHSH inequality of continuous variables. By introducing the phase accumulation between cyclic interactions, the unidirectional transmission of quantum state between the optical mode and two mechanical modes is achieved. The results show that nonreciprocal transmissions are achieved as long as the accumulated phase reaches a certain value. In addition, the effective interaction parameters in our system are amplified, which reduces the difficulty of the implementation of our protocol. Our research can provide potential applications for nonlocal manipulation and transmission control of quantum platforms.
Demixing in the plasma created in capillary discharges with polymeric wall
Authors: Pashchina A S
Published: December 2021

The results of spectral diagnostics of erosion plasma obtained in a pulsed discharge in a capillary with an evaporating wall made of hydrogen-carbon and fluorine-carbon polymers - polymethylmethacrylate and polytetrafluoroethylene - are presented. It was found that in both cases the distribution of chemical elements along the discharge radius is highly inhomogeneous, and their concentration ratio differs significantly from that in the capillary wall. The mass of particles is a common sign characterizing the demixing degree of chemical elements and direction of diffusion flows in fluorine-carbon and hydrogen-carbon plasmas. In both cases, lightweight particles are concentrated in the central high-temperature region, while heavy ones run away onto the low-temperature peripheral region of the discharge. Estimates show that the thermal diffusion mechanism is quite capable for providing the observed demixing degree of chemical elements. Favorable conditions for thermal diffusion processes are formed in the layer adjacent to the capillary wall, where the intense dissociation of radicals occurs, and the temperature gradient reaches up to ΔT∼10 eV/mm.
Intensification of mixing of fuel with supersonic air flow when injection and electric discharge are combined
Authors: Firsov A A , Efimov A V , Kolosov N S , Moralev I A , Leonov S B
Published: December 2021

This paper presents the results of experimental investigations of DC discharge influence on mixing intensification of transvers injected gas jet into supersonic aiflow. The air was used as injected gas to prevent the influence of chemical reactions on measurements. The data obtained during discharge includes current and voltage acquisition, registration of pressure pulsations in the jet downstream of discharge operation accompanied by correlation and Fourier analysis allowed to conclude that discharge significantly increase the pressure pulsations in a wide frequency range of 1000 Hz to 50kHz. Increase of the oscillations near the jet boundary is assumed to be related to kinematic mixing intensification of the injected gas with the oncoming flow.
Extrusion of a nanosecond surface discharge plasma near a dielectric ledge
Authors: Znamenskaya I , Tatarenkova D , Mursenkova I , Kuli-Zade T , Karnozova E
Published: December 2021

The presence of a dielectric ledge along the pulse discharge propagation led to a redistribution of the pulsed surface (plasma sheets) discharge glow. Discharge glow on the surface without the ledge, was uniform and lasted no more than 200 ns. Two plasma channels with increased glow intensity were observed near the rectangular ledge placed in the discharge area. The duration of these longitudinal plasma channels increased and lasted for about 0.9 μs (at a voltage of 25 kV and a density of 0.03 – 0.18 kg/m3
). A nine-frame nanosecond camera recorded the evolution of the plasma glow. The dynamics of the flow induced by the pulse surface discharge was recorded using a high-speed shadow imaging during 40-50 μs after the ignition of the discharge.
CFD simulation of DC-discharge in airflow
Authors: Tarasov D A , Firsov A A
Published: December 2021

The main purpose of this work is to simulate a dynamics of DC discharge in a subsonic airflow. The calculations were performed in the FlowVision 3.12.01 software package. The single-fluid model (MHD approach) of equilibrium plasma was used while the initial discharge channel was set manually. Cylindrical coaxially arranged electrodes were located in the central part of the calculation area, in the core of the airflow. A 5A DC discharge at atmospheric pressure was considered, as well as a simple model of a re-breakdown between parts of discharge filament. In this work, three-dimensional distributions of temperature and current density were obtained during an evolution of discharge in a flow. Discharge channel extension by the airflow and partial channel decay after the re-breakdown process were shown.
Combustion in a supersonic flow using a pylon equipped with a plasma actuator
Authors: Firsov A A , Kolosov N S
Published: December 2021

Plasma-assisted combustion approach is well known for organizing stable ignition and flame holding in supersonic flows in model scramjet combustion chambers. In this work, a new geometry of pylon equipped by electrodes relative to developed earlier was proposed and experimentally investigated. Stable ignition and flame holding were obtained over a wide range of fuel flow rate and discharge currents. Reducing of the energy input in comparison with the previously considered configurations was also demonstrated.
Spectral study of argon-methane mixture plasma jet generated by a DC plasmatron
Authors: Kavyrshin D I , Shavelkina M B , Chinnov V F , Miazin A S
Published: December 2021

We present the results of studying optical emission spectra of Ar:CH4 plasma produced on a DC plasmatron for graphene synthesis. We have identified the basic set of spectral lines and bands in the obtained spectra and shown that H lines and C2 bands appear due to direct excitation by an electron strike of corresponding neutral particles. C2 molecular bands were also identified in the spectra with intensity considerably lower compared to previous studies where He: C2H2 mixture was used as plasma-forming gas.
Radial current distribution along the ionization wave propagating in a long dielectric capillary tube filled with a low-pressure helium
Authors: Akishev Yu S , Karalnik V B , Petryakov A V
Published: December 2021

The experimental results on the study of the ionization wave propagating along a long capillary tube are presented. The ionization wave was initiated by high-voltage pulse of positive or negative polarity. The propagation of this surface ionization wave precedes and influences the establishment of complete electric breakdown within the tube. The spreading of this wave is accompanied by the surface charge deposition. The usage of the fine-sectioned outer electrode allows one to find out the general features of the ionization waves.
Features of photon diffusion in a dispersed medium
Authors: Galaktionov A V
Published: December 2021

Energy transfer by thermal radiation in a dispersed medium with a variable refractive index is discussed. This transfer can be described by a surprisingly simple diffusion equation. The process is naturally to interpret as the photon diffusion. The diffusion equation is free from strict conditions of applicability of the radiation transfer equation, which are usually not satisfied in disperse media with densely packed inhomogeneities. Quantum constraints on the value of the photon diffusion coefficient are derived. These restrictions turn out to be similar to the conditions for the applicability of geometric optics. The lower limit of the thermal conductivity coefficient is obtained, which is easier to verify in the experiment. An independent derivation of this limitation is given from considerations of symmetry and dimension.
Results of studies of the direct current generator of low-temperature nitrogen-propane plasma
Authors: Gadzhiev M Kh , Tyuftaev A S , Ilyichev M V , Sargsyan M A , Yusupov D I , Son E E
Published: December 2021

The effect of propane-butane addition to the plasma-forming gas on the state of cathodes with inserts made from lanthanated tungsten and hafnium is investigated. With a small propane addition (1%), the restorative effect of the insert material is noted, and the propane consumption has an upper limit when it is introduced together with the plasma-forming gas (no more than ∼ 73% of the plasma-forming gas consumption), below which the arc stability is not disturbed.
Chromatographic analysis of a cold plasma jet generated by an electrode microwave discharge in argon flow, interacting with atmospheric air
Authors: Chepelev V M , Chistolinov A V , Antipov S N , Gadzhiev M Kh
Published: December 2021

Application of gas chromatography in analysis of a cold plasma jet generated by an atmospheric pressure microwave discharge in argon flow was considered. Previously developed 2.45-GHz-plasmatron with the external 6-rod-electrode plasma torch was used as a microwave plasma source. The analysis of gaseous samples showed that CO concentration increases by 5-6 times and new gaseous products appear – H2 and CH4 as a result of plasma-gas interaction. The production of CO, H2 and O2 occurs in the processes of dissociation of CO2 and water vapor in the nonequilibrium plasma through the vibrationally excited states.
Development of a control system to maintain steady transition boiling
Authors: Haramura Y , Kajikawa Y
Published: December 2021

Steady transition boiling offers opportunities to observe fluid behavior and to measure transient and local heat flux as the surface dries and wets. This report discusses temperature control in transition boiling. Each component in the control system is either measured or estimated, and the controller parameters are determined along with the optimum depth of the temperature feedback point. Experiments are performed to verify the theoretical stability limit.
Heat transfer and critical heat flux for two-phase immersion cooling of an inverter power module
Authors: Jollyn I T’ , Nonneman J , De Paepe M
Published: December 2021

Heat transfer and critical heat flux measurement are reported for pool boiling cooling of the base plate of an inverter power module. Novec 649 is used as refrigerant. Heat fluxes up to 14.6 W/cm2 were applied with refrigerant saturation temperatures of 36 °C, 41 °C and 46 °C. The measured boiling curves are comparable to those reported for similar refrigerants. The critical heat fluxes range from 12.1 W/cm2 to 14.6 W/cm2, which corresponds within 10% to the correlation of Zuber. The critical heat flux is significantly lower than the highest heat fluxes expected from the power module, indicating that methods to increase the critical heat flux are needed to enable two-phase power module cooling.
Life of a single bubble growing within an electric field in microgravity: some preliminary results of the Reference mUltiscale Boiling Investigation
Authors: Garivalis A I , Di Marco P
Published: December 2021

The experimental outcomes of single bubbles nucleated and growth from a heated surface immersed in an electric field in high-quality microgravity level are presented. Data were obtained between September 2019 and January 2021 from the European experiment known as Reference mUltiscale Boiling Investigation (also multiscale boiling project), in which single bubbles of FC-72 were nucleated on a heated surface, on-board the International Space Station. In the experiments reported here, an electrostatic field is imposed in the boiling region by a washer-shaped electrode, centred above the nucleation site. The bubbles are heavily distorted by the electric stresses; in particular, contact angles and contact line length increase with electric field intensity. In the appropriate conditions, bubbles are continuously and regularly sucked towards the electrode, because they are attracted to regions of weaker electric field. The significant contribution of electro-convection is highlighted by the bubbles growth rate. These preliminary results contribute to the insight of the basics of boiling and show promising opportunities for practical application of electric fields in space.