bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supersonic Nozzle Design
Authors: Puckett A. E. 
Published: March 2021

Abstract
A two-dimensional flow field in which the velocity is everywhere supersonic can always be represented approximately by a number of small adjacent quadrilateral flow fields in each of which the velocity and pressure are constant. These quadrilaterals must be separated by lines representing waves in the flow; changes in velocity and pressure through any wave can be computed. By increasing the number of small areas into which the complete flow field is divided, the accuracy of this approximate solutions may be increased without limit. This constitutes the “method of characteristics” solution, which has been known for many years. This method may be applied to the graphical computation of flow in a supersonic nozzle, with the particular aim of producing uniform supersonic flow at the end of the nozzle. It is pointed out that such a computation is essentially simple and rapid, and its essential features are presented in a form which, it is hoped, may be easily applied to engineering problems.
Control and Prediction of Pulsation Frequency in a Duct System
Authors: Heath W. R. , Elliot W. R. 
Published: March 2021

Abstract
The authors present the results of studies on compressor-duct systems which are characterized by unstable operation over some portion of the performance curves. The principles of the Helmholtz resonator are explained, and the prediction of pulsations in a duct system may be developed by considering that the system acts as a simple Helmholtz resonator. For certain cases electrical analogy is used to explain acoustical conditions in the duct. Methods of preventing pulsations are described.
A Sector-Cascade Test Rig for Measurements of Heat Transfer in Turbine Center Frames
Authors: Jagerhofer Patrick R. , Patinios Marios , Erlacher Gerhard , Glasenapp Tobias , Göttlich Emil , Farisco Federica 
Published: March 2021

Abstract
The turbine center frame (TCF) is an inherent component of turbofan aircraft engines and is used for connecting the high-pressure turbine (HPT) to the low-pressure turbine (LPT). Its position immediately downstream of the HPT makes it susceptible to the extremely high temperatures of future engines. Despite this, fundamental knowledge of heat transfer in TCFs and the influencing factors is still missing. This paper presents a new 45-deg sector-cascade test rig specifically designed for fundamental studies of film cooling effectiveness and heat transfer coefficient in TCFs and the development and validation of a measurement technique involving infrared thermography and heating foils. Measurements of heat transfer coefficient in the TCF were taken for two purge-to-mainstream mass flow ratios corresponding to the case of no purge and nominal (to engine operation) purge. The magnitude of the heat transfer coefficients on the hub and strut surfaces was highly influenced by the various flow structures in the passage and by the velocity variation of the mainstream flow due to the “aggressive” design of the TCF. Heat transfer on the surface of the strut was mainly governed by boundary layer behavior (laminar near the leading edge and turbulent for the rest of the strut) augmented by the effect of the secondary flow structures. Measurements of film cooling effectiveness were also taken for the single case of the nominal purge. A region of high film cooling effectiveness was observed, extending from the purge cavity exit to about 40% of the passage axial length. In this region, the effectiveness decreased with increasing axial length. On the surface of the struts and fillet radii, the film cooling effectiveness was found to be zero. This was attributed to the effect of the horseshoe vortex that sweeps the purge flow away from the strut surface and dilutes it by continuously entraining hot mainstream flow.
High-Fidelity Simulations of Multi-Jet Impingement Cooling Flows
Authors: Otero-Pérez J. Javier , Sandberg Richard D. , Mizukami Satoshi , Tanimoto Koichi 
Published: March 2021

Abstract
This article shows the first parametric study on turbulent multi-jet impingement cooling flows using large-eddy simulations (LES). We focus on assessing the influence of the inter-jet distance and the cross-flow conditions on the heat transfer at the impingement wall. The LES setup is thoroughly validated with both experimental and direct numerical simulation data, showing an excellent agreement. The inter-jet distance effect on the heat transfer is studied comparing three different distances, where the full Nusselt number profile decreases in amplitude when the jet distance is increased. To evaluate the cross-flow effects, we prescribe both laminar and turbulent inflow conditions at different cross-flow magnitudes ranging between 20% and 40% of the impinging jet speed. Large cross-flow intensities cause a jet deflection that reduces the maxima in the Nusselt number distribution, and it increases the heat transfer in the areas of the wall less affected by the jet impingement. Adding realistic turbulent fluctuations to the inflow enhances the cross-flow effects on the heat transfer at the impingement wall.
Heat Transfer in a Rotating, Two-Pass, Variable Aspect Ratio Cooling Channel With Profiled V-Shaped Ribs
Authors: Chen I-Lun , Sahin Izzet , Wright Lesley M. , Han Je-Chin , Krewinkel Robert 
Published: March 2021

Abstract
The thermal performance of two V-type rib configurations is measured in a rotating, two-pass cooling channel. The coolant travels radially outward in the rectangular first pass (aspect ratio (AR—channel width:height) = 4:1) and radially inward in the second pass (AR = 2:1). Both the passages are oriented 90 deg to the direction of rotation. The leading surface (LS) and trailing surface (TS) of the channel are roughened with V-type ribs. The first V-shaped configuration has a narrow gap at the apex of the V. The configuration is modified by off-setting one leg of the V to create a staggered discrete, V-shaped configuration. The ribs are oriented 45 deg relative to the streamwise coolant direction. The heat transfer enhancement and frictional losses are measured with varying Reynolds and rotation numbers. The Reynolds number varies from 10,000 to 45,000 in the AR = 4:1 first pass; this corresponds to 16,000 to 73,500 in the AR = 2:1 second pass. The maximum rotation numbers are 0.39 and 0.16 in the first and second passes, respectively. The heat transfer enhancement on both the leading and trailing surfaces of the first pass of the 45 deg V-shaped channel is slightly reduced with rotation. In the second pass, the heat transfer increases on the leading surface, while it decreases on the trailing surface. The 45 deg staggered, discrete V-shaped ribs provide increased heat transfer and thermal performance compared to the traditional V-shaped and standard, 45 deg angled rib turbulators.
Experimental Study on Film Cooling Effectiveness of Blade With Chevron-Shaped Holes Under Wake Influence
Authors: Li Ji-Chen , Zhu Hui-Ren , Liu Cun-Liang , Ye Lin , Zhou Dao-En 
Published: March 2021

Abstract
Gas turbines have been widely used. With the continuous improvement of the performance of gas turbines, the turbine inlet temperature has greatly exceeded the heat-resistance limit of the turbine blade material, so advanced cooling technology is required. The film cooling effectiveness distribution over the blade under the effect of wake was obtained by the pressure-sensitive paint (PSP) technique. The test blade has five rows of chevron film holes on the pressure side, three rows of cylindrical film holes on the leading edge, and three rows of chevron film holes on the suction side. The mainstream Reynolds number is 130,000 based on the blade chord length, and the mainstream turbulence intensity is 2.7%. The upstream wake was simulated by the spoken-wheel type wake generator. The film cooling effectiveness was measured at three wake Strouhal numbers (0, 0.12, and 0.36) and three mass flux ratios (MFR1, MFR2, and MFR3). The results show that the increase of mass flux ratio leads to a decrease of the film cooling effectiveness on the suction surface. In the wake condition, the effect of mass flux ratio is weakened. Wake leads to a marked decrease of the film cooling effectiveness over most blade surface except for the surface near leading edge on the pressure surface. In the high mass flux ratio condition, the effect of wake on the film cooling effectiveness is weakened on the suction surface and strengthened on the pressure surface.
Free-Stream Turbulence-Induced Boundary-Layer Transition in Low-Pressure Turbines
Authors: Ðurović Kristina , De Vincentiis Luca , Simoni Daniele , Lengani Davide , Pralits Jan , Henningson Dan S. , Hanifi Ardeshir 
Published: March 2021

Abstract
The aerodynamic efficiency of turbomachinery blades is profoundly affected by the occurrence of laminar-turbulent transition in the boundary layer since skin friction and losses rise for the turbulent state. Depending on the free-stream turbulence level, we can identify different paths toward a turbulent state. The present study uses direct numerical simulation as the primary tool to investigate the flow behavior of the low-pressure turbine blade. In the simulations, the flow past only one blade is computed, with periodic boundary conditions in the cross-flow directions to account for the cascade. Isotropic homogeneous free-stream turbulence is prescribed at the inlet. The free-stream turbulence is prescribed as a superposition of Fourier modes with a random phase shift. Two levels of the free-stream turbulence intensity were simulated (Tu=0.19% and 5.2%), with the integral length scale being 0.167c, at the leading edge. We observed that in the case of low free-stream turbulence on the suction side, the Kelvin–Helmholz instability dominated the transition process and full-span vortices were shed from the separation bubble. Transition on the suction side proceeded more rapidly in the high-turbulence case, where streaks broke down into turbulent spots and caused bypass transition. On the pressure side, we have identified the appearance of longitudinal vortical structures, where increasing the turbulence level gives rise to more longitudinal structures. We note that these vortical structures are not produced by Görtler instability.
Features of the Behavior of a Polymer Solution Jet in Electrospinning
Authors: Subbotin A. V. 
Published: March 2021

Abstract
Using the numerical analysis of the force balance equation and the rheological equation of the model of finitely extensible chains, the dynamics of a charged jet during the electrospinning of a polymer solution and the orientation of macromolecules in the jet are studied. In fairly weak electric fields, the jet always remains rectilinear, while in strong fields the straight section of the jet has a finite length, after which the motion of the jet becomes unstable. This behavior is due to the competition between inertial and viscoelastic forces, with viscoelasticity dominating in strong fields. It is found that polymer chains in the jet are strongly stretched along the flow direction.
Production of a Cloned Offspring and CRISPR/Cas9 Genome Editing of Embryonic Fibroblasts in Cattle
Authors: Singina G. N. , Sergiev P. V. , Lopukhov A. V. , Rubtsova M. P. , Taradajnic N. P. , Ravin N. V. , Shedova E. N. , Taradajnic T. E. , Polejaeva I. A. , Dozev A. V. , Brem G. , Dontsova O. A. , Zinovieva N. A. 
Published: March 2021

Abstract
Somatic Cell Nuclear Transfer (SCNT) technique was used to produce the first viable cloned cattle offspring in Russia. Whole-genome SNP genotyping confirmed that the cloned calf was identical to the fibroblast cell line that was used for SCNT. CRISPR/Cas9 approach was subsequently used to knock out genes for beta-lactoglobulin gene (PAEP) and the beta-lactoglobulin-like protein gene (LOC100848610) in the fibroblast cells. Gene editing (GE) efficiency was 4.4% for each of these genes. We successfully obtained single-cell-derived fibroblast colonies containing PAEP and LOC100848610 knockouts, which will be used to produce beta-lactoglobulin-deficient cattle.
Methane Adsorption on Microporous Carbon Adsorbent Prepared from Thermochemically Activated Wood
Authors: Fomkin A. A. , Dubovik B. A. , Limonov N. V. , Pribylov A. A. , Pulin A. L. , Men’shchikov I. E. , Shkolin A. V. 
Published: March 2021

Abstract—
An EC-103 microporous carbon adsorbent was synthesized from wood using thermochemically activation with Н3РО4 as an activating agent. Methane adsorption on the EC-103 adsorbent was studied within the temperature range from 303 to 333 K and at pressures up to 40 MPa. The total volume of sorbing pores was 1.71 cm3/g. The maximum values of methane adsorption were obtained at the temperature of 303 K and pressure of 40 MPa. The differential molar isosteric heat of methane adsorption 14.5 mmol/g (23.2 wt %) was on the average of 12−14 kJ/mol. Methane adsorption on the EC-103 adsorbent was calculated based on the Dubinin theory of volume filling of micropores (TVFM). It was shown that the Dubinin-Radushkevich equation and basic TVFM pattern provided the best description of experimental data on methane adsorption with the use of only the standard structural and energy characteristics of the adsorbent.
Unicortical sternal graft reconstruction for anterior sternoclavicular joint instability
Authors: Parker Kate M , Somerson Jeremy S , Warme Winston J 
Published: March 2021

Sternoclavicular joint (SCJ) injury represents 3%–5% of all shoulder girdle injuries, yet can produce significant pain and disability. While conservative management improves symptoms in most cases, surgical intervention may be indicated for patients with symptoms recalcitrant to nonoperative treatment. A wide range of surgical stabilisation techniques is documented in the literature; however, the scarcity of SCJ pathology has hindered development of a ‘gold standard’.We present a minimalistic medial clavicle osteoplasty and SCJ reconstruction using semitendinosus autograft anchored with unicortical sternal tunnels in the 54 years old with chronic SCJ instability. This technique can be performed safely, resulting in joint stability and pain reduction, while avoiding risks and complications noted in the literature with other techniques.
Across-subjects multiple baseline trial of exposure-based cognitive-behavioral therapy for severe irritability: a study protocol
Authors: Naim Reut , Kircanski Katharina , Gold Andrea , German Ramaris E , Davis Mollie , Perlstein Samantha , Clayton Michal , Revzina Olga , Brotman Melissa A 
Published: March 2021

IntroductionIrritability is defined as a tendency towards anger in response to frustration. Clinically, impairing irritability is a significant public health problem. There is a need for mechanism-based psychotherapies targeting severe irritability as it manifests in the context of disruptive mood dysregulation disorder (DMDD). This study protocol describes a randomised multiple baseline design testing the preliminary efficacy of a new treatment, exposure-based cognitive-behavioral therapy for severe irritability in youth, which also integrates components of parent management training. We will investigate associations of this intervention with primary clinical measures, as well as ecological momentary assessment measures.Methods and analysisForty youth will be enrolled. Participants, aged 8–17 years, must present at least one of two core symptoms of DMDD: abnormal mood or increased reactivity to negative emotional stimuli, with severe impairment in one domain (home, school, peers) and moderate in another, or moderate impairment in at least two domains. Each participant is randomised to a 2-week, 4-week or 6-week baseline observation period, followed by 12 active treatment sessions. Clinical ratings are conducted at baseline, biweekly (clinician), weekly (parent/child) throughout treatment, post-treatment, and 3-month and 6-month follow-up (clinician). Clinician ratings on the Affective Reactivity Index and Clinical Global Impressions-Improvement scale for DMDD are our primary outcome measures. Secondary outcome measures include parent and child reports of irritability. Post hoc additional symptom measures include clinician, parent and self-ratings of depression, anxiety and overall functional impairment. Prospective, digitally based event sampling of symptoms is acquired for a week pre-treatment, mid-treatment and post-treatment. Based on our pathophysiological model of irritability implicating frustrative non-reward, aberrant threat processing and instrumental learning, we probe these three brain-based targets using functional MRI paradigms to assess target engagement.Ethics and disseminationThe research project and all related materials were submitted and approved by the appropriate Institutional Review Board (IRB) of the National Institute of Mental Health (NIMH).Trial registration numbersNCT02531893andNCT00025935.
Systematic review protocol to assess artificial intelligence diagnostic accuracy performance in detecting acute ischaemic stroke and large-vessel occlusions on CT and MR medical imaging
Authors: Kundeti Srinivasa Rao , Vaidyanathan Manikanda Krishnan , Shivashankar Bharath , Gorthi Sankar Prasad 
Published: March 2021

IntroductionThe use of artificial intelligence (AI) to support the diagnosis of acute ischaemic stroke (AIS) could improve patient outcomes and facilitate accurate tissue and vessel assessment. However, the evidence in published AI studies is inadequate and difficult to interpret which reduces the accountability of the diagnostic results in clinical settings. This study protocol describes a rigorous systematic review of the accuracy of AI in the diagnosis of AIS and detection of large-vessel occlusions (LVOs).Methods and analysisWe will perform a systematic review and meta-analysis of the performance of AI models for diagnosing AIS and detecting LVOs. We will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols guidelines. Literature searches will be conducted in eight databases. For data screening and extraction, two reviewers will use a modified Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist. We will assess the included studies using the Quality Assessment of Diagnostic Accuracy Studies guidelines. We will conduct a meta-analysis if sufficient data are available. We will use hierarchical summary receiver operating characteristic curves to estimate the summary operating points, including the pooled sensitivity and specificity, with 95% CIs, if pooling is appropriate. Furthermore, if sufficient data are available, we will use Grading of Recommendations, Assessment, Development and Evaluations profiler software to summarise the main findings of the systematic review, as a summary of results.Ethics and disseminationThere are no ethical considerations associated with this study protocol, as the systematic review focuses on the examination of secondary data. The systematic review results will be used to report on the accuracy, completeness and standard procedures of the included studies. We will disseminate our findings by publishing our analysis in a peer-reviewed journal and, if required, we will communicate with the stakeholders of the studies and bibliographic databases.PROSPERO registration numberCRD42020179652.
The control of pain due to dentin hypersensitivity in individuals with molar–incisor hypomineralisation: a protocol for a randomised controlled clinical trial
Authors: Sobral Ana Paula Taboada , Santos Elaine Marcilio , Aranha Ana Cecilia , Soares Paulo Vinícius , Moriyama Caroline Moraes , Gonçalves Marcela Leticia Leal , Ribeiro Rodrigo Alves , Motta Lara Jansiski , Horliana Anna Carolina Ratto Tempestini , Fernandes Kristianne Porta Santos , Mesquita-Ferrari Raquel Agnelli , Bussadori Sandra Kalil 
Published: March 2021

IntroductionDentin hypersensitivity (DH) is defined as high sensitivity of the vital dentin when exposed to thermal, chemical or tactile stimuli. Two mechanisms are required for the occurrence of DH: (1) the dentin must be exposed and (2) the dentinal tubules must be open and connected to the pulp. Molar–incisor hypomineralisation (MIH) is a qualitative abnormality of a genetic origin that affects tooth enamel and, in most cases, is accompanied by DH. The control of tooth sensitivity is fundamental to the successful treatment of MIH. The aim of the proposed randomised, controlled, clinical trial is to evaluate the effectiveness of different protocols for the control of DH in patients with teeth affected by MIH.Methods and analysisOne hundred and forty patients who meet the inclusion criteria will be allocated to four groups. Group 1 will be the control group (placebo). In Group 2, sensitive teeth will be sealed with PermaSeal (Ultradent). In Group 3, sensitive teeth will receive low-level laser (LLL, AsGaAl) at a wavelength of 780 nm (Laser XT Therapy, DMC, São Carlos, Brazil). In Group 4, sensitive teeth will be treated with both LLL and PermaSeal (Ultradent). DH will be evaluated 15 min after the application of the treatments and the patients will be reevaluated 1 week, 1 month, 3 months and 6 months after the treatments. The primary outcome of this study is change in pain/sensitivity, when evaluated through a Visual Analogue Scale, to determine the effectiveness of the proposed treatments, as well as differences among the evaluation times for each proposed treatment.Ethics and disseminationThis protocol has been ethically approved by the local medical ethical committee (protocol number: 4.020.261). Results will be submitted to international peer-reviewed journals and presented at international conferences.Trial registration numberNCT04407702.