bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood prognostic predictors of treatment response for patients with papillary thyroid cancer
Authors: Liu Xiangxiang , Huang Zhongke , He Xianghui , Zheng Xiangqian , Jia Qiang , Tan Jian , Fan Yaguang , Lou Cen , Meng Zhaowei
Published: October 2020

Background: Papillary thyroid cancer (PTC) is a very common malignant disease with high morbidity. We needed some pretreatment indicators to help us predict prognosis and guide treatment. We conducted a study about some pretreatment prognostic indicators.

Methods: This clinical study recruited 705 postoperative PTC patients (211 males, 494 females). Clinical data before radioactive iodine (RAI) treatment were collected. Patients’ response to therapy were classified into two categories: ‘Good Prognosis Group’ (GPG) and ‘Poor Prognosis Group’ (PPG), according to ‘2015 American Thyroid Association Guidelines’. Differences of indicators between different prognosis groups were compared. Odds ratios (ORs) were calculated by univariate/multiple binary logistic regression models. Difference of body mass index (BMI) changes before and after RAI treatment between different prognosis groups was also compared.

Results: A total of 546 (77.45%) belonged to GPG, and 159 (22.55%) belonged to PPG. Platelet (PLT), neutrophil (NEUT), PLT subgroups, and combination of red blood cell distribution width (RDW) and BMI (COR-BMI) were different between two prognosis groups. The significance of the difference between the two groups of BMI disappeared after the Bonferroni correction. PLT and PLT subgroups had detrimental effects on the risk of PPG; T stage had a positive effect on the risk of PPG. PLT subgroup showed a detrimental effect on the risk of PPG when we included additional covariates.

Conclusions: We found that lower pretreatment PLT levels may indicate a poor prognosis for PTC. The relationship between platelet-derived growth factor (PDGF) and radiation sensitivity may be the key to this association.
MINOT: Modeling the intracluster medium (non-)thermal content and observable prediction tools
Authors: Adam R. , Goksu H. , Leingärtner-Goth A. , Ettori S. , Gnatyk R. , Hnatyk B. , Hütten M. , Pérez-Romero J. , Sánchez-Conde M. A. , Sergijenko O.
Published: October 2020

In the past decade, the observations of diffuse radio synchrotron emission toward galaxy clusters revealed cosmic-ray (CR) electrons and magnetic fields on megaparsec scales. However, their origin remains poorly understood to date, and several models have been discussed in the literature. CR protons are also expected to accumulate during the formation of clusters and probably contribute to the production of these high-energy electrons. In order to understand the physics of CRs in clusters, combining of observations at various wavelengths is particularly relevant. The exploitation of such data requires using a self-consistent approach including both the thermal and the nonthermal components, so that it is capable of predicting observables associated with the multiwavelength probes at play, in particular in the radio, millimeter, X-ray, andγ-ray bands. We develop and describe such a self-consistent modeling framework, calledMINOT(modeling the intracluster medium (non-)thermal content and observable prediction tools) and make this tool available to the community.MINOTmodels the intracluster diffuse components of a cluster (thermal and nonthermal) as spherically symmetric. It therefore focuses on CRs associated with radio halos. The spectral properties of the cluster CRs are also modeled using various possible approaches. All the thermodynamic properties of a cluster can be computed self-consistently, and the particle physics interactions at play are processed using a framework based on theNaimasoftware. The multiwavelength observables (spectra, profiles, flux, and images) are computed based on the relevant physical process, according to the cluster location (sky and redshift), and based on the sampling defined by the user. With a standard personal computer, the computing time for most cases is far shorter than one second and it can reach about one second for the most complex models. This makesMINOTsuitable for instance for Monte Carlo analyses. We describe the implementation ofMINOTand how to use it. We also discuss the different assumptions and approximations that are involved and provide various examples regarding the production of output products at different wavelengths. As an illustration, we model the clusters Abell 1795, Abell 2142, and Abell 2255 and compare theMINOTpredictions to literature data. WhileMINOTwas originally build to simulate and model data in theγ-ray band, it can be used to model the cluster thermal and nonthermal physical processes for a wide variety of datasets in the radio, millimeter, X-ray, andγ-ray bands, as well as the neutrino emission.
Cost for a controlled linear KdV equation
Authors: Krieger Joachim , Xiang Shengquan
Published: October 2020

The controllability of the linearized KdV equation with right Neumann control is studied in the pioneering work of Rosier [L. Rosier, ESAIM: COCV 2 (1997) 33-55.]. However, the proof is by contradiction arguments and the value of the observability constant remains unknown, though rich mathematical theories are built on this totally unknown constant. We introduce a constructive method that gives the quantitative value of this constant.
Mechanical properties of lightweight concrete with sintered aggregate
Authors: Rogowska Anna M. , Lewiński Paweł M.
Published: October 2020

The objective of this paper is the determination of short-term properties of lightweight concrete with sintered aggregate. The aggregate material comes from the recycling of ashes from power plants, which yield granules after processing. The research was planned based on two concrete mixes. A series of tests was carried out in the ITB Laboratory of Building Structures, Geotechnics and Concrete. As a result of these tests, the following parameters were determined: secant modulus of elasticity and cylinder strength of concrete, cube strength of concrete, axial tensile strength, splitting tensile strength, flexural strength and concrete shrinkage. Knowledge of the tested parameters is necessary when designing prestressed structures, as well as accepting proven values for static calculations when designing complex engineering structures, including prestressed elements made of lightweight concrete.
Behaviour of reinforcement in drop tower beam tests
Authors: Leicht Lena , Bracklow Franz , Hering Marcus , Curbach Manfred
Published: October 2020

Drop tower tests help to gain understanding about the general behaviour of reinforced concrete members under impact loading and to analyse strains and strain rates occurring within their reinforcement. For this purpose, beam and slab specimens are usually employed. The main advantage of beams compared to slabs is that they are less complex due to the almost two-dimensional instead of three-dimensional wave propagation within them. To investigate the steel strains and strain rates, ten impact tests on beam specimens with various impact energies were performed. The impactor sizes and velocities were varied. The reinforcement bars of the beams were instrumented with semiconductor strain gauges. The measured data suggest that the occurring strains in beam tests are independent of the loading velocity. The same was found for the strain rates. The reason is that higher impact energies mostly influence the concrete damage due to spalling on the impact-facing side which happens after the maximum strains occurred. The strains in the reinforcement bars generally result from the overall deflection because of the impact, the spreading of longitudinal waves in the horizontal direction, and the localized cracking of the concrete due to the formation of a punching cone.
Analytical solution for the resistance of composite beams subjected to bending
Authors: Lechman Marek
Published: October 2020

The paper deals with the resistance of steel and concrete composite beams, named BH beams, subjected to bending. They are structurally connected with prefabricated or castin situslabs, forming floor slab system. The beams under consideration consist of the reinforced concrete (RC) rectangular core placed inside a reversed TT welded profile. The stress-strain relationship for concrete in compression of the RC core is assumed for nonlinear analysis according to Eurocode 2. For reinforcing and profile steels linear elastic – ideal plastic model is applied. The normalized ultimate bending moment determining the resistance of the BH beam is derived by integrating the equilibrium equations of the bending moments about the horizontal axis of the RC core rectangle, taking into account the physical and geometrical relationships. The presented model was verified by tests carried out on two BH beams subjected to bending. The comparisons made indicated good convergence between the analytical solution and the experimental results in ultimate bending moments.
Effect of fine recycled aggregates on the properties of non-cement blended materials
Authors: Lin Wei-Ting , Fiala Lukáš , Cheng An , Petříková Michaela
Published: October 2020

In this study, the different proportions of co-fired fly ash and ground granulated blast-furnace slag were used to fully replace the cement as non-cement blended materials in a fixed water-cement ratio. The recycled fine aggregates were replaced with natural fine aggregates as 10%, 20%, 30%, 40% and 50%. The flowability, compressive strength, water absorption and scanning electron microscope observations were used as the engineered indices by adding different proportions of recycled fine aggregates. The test results indicated that the fluidity cannot be measured normally due to the increase in the proportion of recycled fine aggregates due to its higher absorbability. In the compressive strength test, the compressive strength decreased accordingly as the recycled fine aggregates increased due to the interface structure and the performance of recycled aggregates. The fine aggregates and other blended materials had poor cementation properties, resulting in a tendency for their compressive strength to decrease. However, the compressive strength can be controlled above 35 MPa of the green non-cement blended materials containing 20% recycled aggregates.
Research on semi-precast prestressed concrete slab under short-term and long-term load
Authors: Zając Jakub , Drobiec Łukasz , Jasiński Radosław , Mazur Wojciech , Grzyb Krzysztof , Kisiołek Artur
Published: October 2020

Tests of a full-scale model of slab with the dimensions of 6.30x6.30m, built of TerivaPanel panels were carried out under short-term and long-term load. TerivaPanel panels are partial precast, pre-tensioned concrete slabs with ribs connected at the bottom. The panels have a specially shaped cross-connection (shear key) enabling loads to be transferred between the panels. The tests were carried out under a load placed on the top of the slab. Additionally, the load was applied sequentially. Measurements were made by an electronic method. In one of the stages, long-term testing, the load was applied to one half of the slab to examine the possibility of faulting. The measurements were carried out at monthly intervals, using a geodetic method. The values of vertical displacements at the panel joints (in the middle of the slab) and for central panels along the entire length of the joint were measured.
Analysis of confined masonry with Strut and Tie models
Authors: Drobiec Łukasz , Mazur Wojciech , Rybarczyk Tomasz
Published: October 2020

Strut & Tie (S-T) models are used quite commonly for the analysis of reinforced concrete structures and in the calculation of masonry structures. Creating the S-T model of the confined masonry is slightly different from models of reinforced concrete or models of classic masonry structures. These models should take into account different stiffness of concrete and masonry. This article proposes a Strut & Tie model for the analysis of confined masonry. The results of calculations were compared with the results of tests of full scale masonry walls with and without opening. Good compliance of the calculation results of S-T models with the test results was obtained.
Evaluation of seismic performance measures for MDOF RC structures subjected to simulated and real ground motions
Authors: Karimzadeh Shaghayegh , Askan Aysegul , Yakut Ahmet
Published: October 2020

Nonlinear time history analyses of structures require full time series of ground motion records. For regions with sparse seismic networks or potential large earthquakes, ground motion simulation has gained more attention in recent years. Simulated records are required to be generated using regional input dataset and then verified against existing recorded ground motions of past events. To use simulated ground motions in engineering applications, estimation of reliable seismic demand parameters is essential. In this study, the real and simulated records of the 2009 L’Aquila, Italy earthquake with (Mw=6.3) are investigated for their use in engineering practice. In the first step, misfits are evaluated for alternative seismological measures (peak values, duration and frequency as well as energy content of the time histories). Next, varying multi-degree-of-freedom reinforced concrete structures with different number of stories are selected. Numerical models of the structures are performed in the OpenSees platform. Seismic performance measures in terms of inter-story drift ratio for the selected structures are assessed through nonlinear time history analyses for both the real and simulated ground motions. Then, the misfits are estimated in terms of structural demand parameters. Results reveal a good fit between the seismological and engineering demand misfits for the selected ground motion simulation approaches.
Granulozytentransfusion: Update 2020
Authors: Doblinger Nina , Gruber Michael , Ahrens Norbert
Published: October 2020

Die therapeutische Anwendung von Granulozytenkonzentraten erfolgt im klinischen Alltag im Gegensatz zu der anderer Blutprodukte nur selten und unregelmäßig. Der zurückhaltende Einsatz beruht unter anderem auf dem Fehlen einer breiten Evidenz, logistischen und wirtschaftlichen Problemen und dem Vorhandensein anderer potenter Therapieoptionen neutropener Infektionen. Dennoch gab es in den letzten Jahren neue wissenschaftliche Erkenntnisse nicht nur zu Physiologie und Pathophysiologie der Granulozyten, wie neu charakterisierten zellulären Verteidigungsstrategien oder deren Mitwirkung bei thrombotischen oder malignen Ereignissen, sondern auch zu deren therapeutischem Effekt. Dieser wird von einer Vielzahl an Parametern, wie der Art der Infektion, dem Transfusionszeitpunkt und der Dosis, beeinflusst. Das macht die Indikationsstellung zu einer komplexen Einzelfallentscheidung und es gilt, die heterogene Datenlage systematisch zusammenzufassen. Außerdem wurden die etablierten Indikationen neutropener bzw. neutropathischer Infektionen um experimentelle, mögliche neue Anwendungsgebiete wie die Mukositis oder Leukämiebehandlung erweitert. Die erfolgreiche Anwendung setzt eine geeignete, moderne Herstellungsweise voraus. Neben der Apherese, bei der eine relativ hohe Spenderbelastung unter anderem durch Nebenwirkungen von Mobilisationsregime und Sedimentationsbeschleunigern berücksichtigt werden muss, existieren weitere Verfahren wie die Gewinnung von Granulozyten aus Buffy Coats von Vollblutspenden. Diese versprechen eine Reduktion logistischer Probleme und unerwünschter Wirkungen auf den Spender. Unerwünschte Wirkungen bei Empfängern von Granulozytentransfusionen sollten nach wie vor berücksichtigt und gegen einen erhofften therapeutischen Effekt abgewogen werden.
Symmetry does not Indicate Recovery: Single-leg Hop Before and After a Lower Extremity Injury
Authors: Simon Janet E , Yom Jae , Grooms Dustin R
Published: October 2020

Current recommendations for return-to-play decision-making involve comparison of the injured limb to the uninjured limb. However, the use of the uninjured limb as a comparison for hop testing lacks empirical evidence. Thus, the purpose of this study was to determine the effects of lower extremity injury on limb symmetry and performance on the single-leg hop for distance. Two-hundred thirty-six adolescent athletes completed the single-leg hop for distance before the beginning of the season (pre-injury). Forty-four adolescent athletes sustained a lower extremity injury (22 ankle and 12 knee) and missed at least three days of sports participation. All individuals had completed the single-leg hop for distance before the beginning of the season (pre-injury) and at discharge (post-injury). Injured limb single-leg hop for distance significantly decreased at return-to-play from pre-injury with a mean decrease of 48.9 centimeters; the uninjured limb also significantly decreased, with a mean decrease of 33.8 centimeters. Limb symmetry did not significantly change pre- to post-injury with a mean difference of 1.5%. Following a lower extremity injury, single-leg hop for distance performance degrades not only for the injured limb but also the uninjured limb. However, limb symmetry did not change following a lower extremity injury.
Acute Sigmoid Sinus Compromise Following Skull Base Procedures: Is a “Laissez-Faire” Approach Best?
Authors: Arnone Gregory D. , Kunigelis Katherine E. , Gurau Andrei , Coulter Ian , Thompson John , Youssef A. Samy
Published: October 2020

Objective Venous sinus compromise (VSC) of the sigmoid sinus can manifest as either venous sinus thrombosis, stenosis, or a combination of the two. It may occur following retro and presigmoid craniotomy, even in the absence of overt intraoperative sinus injury. Currently, the optimal management of VSC in the perioperative period is not well established. We report our incidence and management of VSC following skull base surgery around the sigmoid sinus.

Patients and Methods A retrospective chart review of all patients undergoing presigmoid, retrosigmoid, or combined approach by the senior author from 2014 to 2019 was performed.

Main Outcome Measures Charts were reviewed for patient demographics, surgical details, details of venous sinus compromise, and patient outcomes. Statistical analyses were performed using R 3.6.0 (R Project).

Results A 115 surgeries were found with a total of 13 cases of VSC (overall incidence of 11.3%). Nine cases exhibited thrombosis and four stenosis. There were no statistically significant differences between the groups with (group 1) or without (group 2) VSC. Operation on the side of the dominant sinus did not predispose to postoperative VSC. Five patients received antiplatelet medication in the perioperative period. There was no difference in outcomes in the group that did not receive antiplatelet medication versus those who did.

Conclusion Acute iatrogenic sigmoid sinus compromise can be managed expectantly. We believe that the treatment for each instance of VSC must be individualized, considering the symptoms of the patient, rather than applying a universal algorithm.
COVID-19 Pandemic in Women–Rheumatologist’s Perspective
Authors: Pinto Benzeeta , Roongta Rashmi
Published: October 2020

COVID-19 has caused unprecedented challenges to every field. Rheumatic diseases (RD) are more common in women compared with men. Patients with RD are predisposed to infections both because of their disease and immunosuppressive medication. The severity of COVID-19 in women is less as compared with men among the general population. It is not known if the risk is higher in women with RD compared with other women. Currently, published data of COVID-19 in RD suggests similar or mildly increased risk in patients with RD but sex disaggregated data is not available. In this article, we review the current evidence of COVID-19 in RD with an emphasis on women.
COVID-19 and Women: An Obstetrician’s Perspective
Authors: Tandon Pooja , Luthra Neeru , Aggarwal Ritika
Published: October 2020

In the era of COVID-19, pregnant patients have genuine concerns regarding their own health and the health of the unborn. It is difficult to provide standard protocols due to extremely limited data. The recommendations and guidelines are being frequently revised as we learn more about the disease.
Understanding the SARS-CoV-2 to Manage COVID-19
Authors: Karak Somdatta , Radha Vegesna
Published: October 2020

The entire scientific community have come together in the last eight months to understand the details of the novel SARS-CoV-2 virus that has caused the COVID-19 pandemic. We now have a fair idea of the main targets that should be looked into in depth to fight the virus. However, the data from different population groups on the different testing or treatment strategies is still largely lacking. Populations are diverse in terms of their genetics, nutritional status, microbiota, access to facilities, among many other factors. This article makes a case for looking into women-specific data on test results, response to disease management strategies, as well as mortality due to COVID-19, otherwise currently missing.
Volumetric Capnography in Pediatric Extracorporeal Membrane Oxygenation: A Case Series
Authors: Derespina Kim R. , Medar Shivanand S. , Aydin Scott I. , Kaushik Shubhi , Al-Subu Awni , Ofori-Amanfo George
Published: October 2020

The kinetics of carbon dioxide elimination (VCO2) may be used as a surrogate for pulmonary blood flow. As such, we can apply a novel use of volumetric capnography to assess hemodynamic stability in patients requiring extracorporeal membrane oxygenation (ECMO). We report our experience of pediatric patients requiring ECMO support who were monitored using volumetric capnography. We describe the use of VCO2 and its association with successful decannulation. This is a prospective observational study of pediatric patients requiring ECMO support at The Children's Hospital at Montefiore from 2017 to 2019. A Respironics NM3 monitor was applied to each patient. Demographics, hemodynamic data, blood gases, and VCO2 (mL/min) data were collected. Data were collected immediately prior to and after decannulation. Over the course of the study period, seven patients were included. Predecannulation VCO2 was higher among patients who were successfully decannulated than nonsurvivors (109 [35, 230] vs. 12.4 [7.6, 17.2] mL/min), though not statistically significant. Four patients (57%) survived without further mechanical support; two (29%) died, and one (14%) was decannulated to Berlin. Predecannulation VCO2 appears to correlate with hemodynamic stability following decannulation. This case series adds to the growing literature describing the use of volumetric capnography in critical care medicine, particularly pediatric patients requiring ECMO. Prospective studies are needed to further elucidate the use of volumetric capnography and optimal timing for ECMO decannulation.
Fehlmedikation: Sicherheitskultur auf allen Ebenen
Authors: Kohrs Jens
Published: October 2020

Ende August sorgte der Tod eines Patienten am Klinikum Bielefeld für Schlagzeilen. Er hatte ein falsches Medikament bekommen. Prof. Dr. Claudia Schmidtke, Patientenbeauftragte der Bundesregierung, plädiert deshalb für mehr digitale Lösungen und einen geschlossenen Medikationsprozess.
Best Practice Award der Prospitalia GMBH: Flexible Managementlösung zur digitalen Rechnungsbearbeitung
Authors: Kucera Martin
Published: October 2020

Zum fünften Mal hat der Einkaufsdienstleister Prospitalia den Best Practice Award für den Bereich Einkauf und Logistik im Krankenhaus verliehen. Gewonnen hat das IT-Konversionsprojekt „SRH Process Excellence“ der SRH-Kliniken.
Soziale Netzwerke: Senden auf allen Kanälen
Authors: Heeser Alexandra
Published: October 2020

Eine Webseite ist Pflicht – und Social-Media-Känäle wie Facebook oder Instagram zählen längst zum Standardrepertoire von Klinik-Kommunikationsabteilungen. Doch wer heute möglichst breit und altersübergreifend Patienten, Mitarbeiter und andere Zielgruppen erreichen will, darf sich darauf nicht ausruhen. Inzwischen lohnen auch Plattformen wie Twitter, YouTube, Snapchat oder TikTok.
Estimates for the eigenvalues of the bi-drifting Laplacian on complete metric measure spaces
Authors: Zeng Lingzhong
Published: October 2020

As we know, it is very difficult to prove an eigenvalue inequality of Ashbaugh–Cheng–Ichikawa–Mametsuka type for the bi-drifting Laplacian on the bounded domain of the complete metric measure spaces. Even assumed that the differential operator is bi-Laplacian on the n-dimensional unit Euclidean sphere, this problem still remains open. However, a general inequality with respect to the bi-drifting Laplacian is successfully established under certain conditions in this paper. Applying the general inequality, we prove some eigenvalue inequalities of Ashbaugh–Cheng–Ichikawa–Mametsuka type on the Gaussian shrinking Ricci soliton and the n-dimensional cigar metric measure spaces (CMMS for short). In particular, we obtain two interesting eigenvalue inequalities of Ashbaugh–Cheng–Ichikawa–Mametsuka type for the CMMS with lower-dimensional topology.
A modular, easy-to-use microcapillary electrophoresis system with laser-induced fluorescence for quantitative compositional analysis of trace organic molecules
Authors: Duca Zachary A. , Speller Nicholas C. , Cantrell Thomas , Stockton Amanda M.
Published: October 2020

Microcapillary electrophoresis (μCE) enables high-resolution separations in miniaturized, automated microfluidic devices. Pairing this powerful separation technique with laser-induced fluorescence (LIF) enables a highly sensitive, quantitative, and compositional analysis of organic molecule monomers and short polymers, which are essential, ubiquitous components of life on Earth. Improving methods for their detection has applications to multiple scientific fields, particularly those related to medicine, industry, and space science. Here, a modular benchtop system using μCE with LIF detection was constructed and tested by analyzing standard amino acid samples of valine, serine, alanine, glycine, glutamic acid, and aspartic acid in multiple borate buffered solutions of increasing concentrations from 10 mM to 50 mM, all pH 9.5. The 35 mM borate buffer solution generated the highest resolution before Joule heating dominated. The limits of detection of alanine and glycine using 35 mM borate buffer were found to be 2.12 nM and 2.91 nM, respectively, comparable to other state-of-the-art μCE-LIF instruments. This benchtop system is amenable to a variety of detectors, including a photomultiplier tube, a silicon photomultiplier, or a spectrometer, and currently employs a spectrometer for facile multi-wavelength detection. Furthermore, the microdevice is easily exchanged to fit the desired application of the system, and optical components within the central filter cube can be easily replaced to target alternative fluorescent dyes. This work represents a significant step forward for the analysis of small organic molecules and biopolymers using μCE-LIF systems.
Development of miniaturized trigatron switch and experimental investigation of its switching performance
Authors: Sharma Ravindra Kumar , Chavan Satish G. , Marathe P. P. , Sharma Archana
Published: October 2020

There is an increasing interest in synchronization of multiple spark gap switches while maintaining compact geometry, less-complex circuit, and low jitter switching performances. A study of the effect of electrical parameters on switching performances is necessary for the operation of a large number of simultaneous switches. A miniaturized trigatron switch assembly (Outer diameter: 35 mm and thickness: 5 mm) is developed and experimentally investigated for switching performance. A polyether ether ketone insulator and brass conductor electrodes are utilized due to their high insulation and solderable properties, respectively. Important switching parameters, delay time, switch time delay, jitter in delay time, discharging peak current, trigger break down time, and trigger break down voltage, are studied under four typical conditions. These four conditions are: (a) a fast trigger (FT) with normal circuit inductance (10 ns, 20 nH); (b) a fast trigger with higher circuit inductance (10 ns and 500 nH); (c) a slow trigger (ST) with normal circuit inductance (250 ns and 20 nH) and (d) a slow trigger with higher circuit inductance (250 ns and 500 nH). Subsequently, three trigatron spark gaps (4 kV, 5 kA, >100 shots, 4 nH, and 20 mΩ) are simultaneously switched within 5 ns time. Many experimental results are the first of their kind in terms of compact switch development, switching performance, and single electrical trigger based synchronization. This paper will also add a good value to presently available knowledge through systematically implementing the simultaneous switching condition for the generation of 5 kA, 50 ns current pulses. These low cost (US$40) trigatron switches can be utilized in low energy, compact pulsed power applications.
Benchmark solution for the hydrodynamic stability of plane porous-Couette flow
Authors: Shankar B. M. , Shivakumara I. S. , Kumar Jai
Published: October 2020

The hydrodynamic stability against small disturbances of plane Couette flow through an incompressible fluid-saturated fixed porous medium between two parallel rigid plates is investigated. The fluid flow occurs because of moving upper and lower plates with a constant speed in the opposite directions, and it is described by using the Brinkman-extended Darcy model with fluid viscosity different from the Brinkman viscosity. The resulting stability eigenvalue problem is solved numerically using the Chebyshev collocation method. The instigation of instability has been determined accurately by computing the critical Brinkman–Reynolds number as a function of the Darcy–Reynolds number. A comparative study between the plane porous-Poiseuille flow and the plane porous-Couette flow has been carried out, and the similarities and the differences are highlighted. For the Darcy and the inviscid fluid cases, the stability of fluid flow is analyzed analytically and found that the flow is always stable.
Kinetic analytical modeling of Gaussian pulse beam-bending including the transient regime
Authors: Ruyer C. , Debayle A. , Loiseau P. , Casanova M. , Masson-Laborde P. E.
Published: October 2020

The advection by a flow of ponderomotively driven density fluctuations may lead to the deflection of a laser pulse. This effect, known as beam bending, may modify the irradiation geometry and energy deposition in high energy laser plasma experiments. A kinetic modeling of beam-bending of a Gaussian laser pulse is proposed and validated by means of “particle-in-cell” simulations over a vast parametric domain, demonstrating the importance of accounting for kinetic damping of driven ion-acoustic waves. The transient regime is also addressed and compared to kinetic simulations.
Influence of pressure transducer protrusion depth on pressure measurements of shock waves in shock tubes
Authors: Thethy Bhavraj , Kaebe Benjamin , Honnery Damon , Edgington-Mitchell Daniel , Kleine Harald
Published: October 2020

This note investigates how small changes in the protrusion depth of a pressure transducer affect the pressure measurement of a moving shock wave. Measurements are undertaken with Kistler, Kulite, and PCB sensors in flush, recessed, and protruded sensor positions. Measurements of both absolute pressure and Mach number are shown to be insensitive to sensor protrusion depth. An assessment of sensor response time indicates a significantly shorter reaction time for the Kulite and PCB sensors compared with the Kistler sensor.
Thermal conductivity analysis of two-dimensional complex plasma liquids and crystals
Authors: Shahzad Aamir , Kashif Muhammad , Munir Tariq , He Maogang , Tu Xin
Published: October 2020

A novel homogeneous perturbed non-equilibrium molecular dynamics (HPMD) scheme, proposed by Evan-Gillan, has been employed to calculate the thermal conductivity of two-dimensional (2D) complex plasma liquids and crystals (CPLCs). The thermal conductivity has been reported using an improved HPMD method under the influence of constant external perturbation with different system sizes (N) and combinations of plasma parameters (Γ, κ). The current HPMD scheme provides precise outcomes with fast convergence for small-to-large N effects over a complete range of (Γ, κ). Temperature scaling law is tested for 2D thermal conductivity with appropriate Einstein frequency and found excellent behaviors. New simulations show that the thermal conductivity of CPLCs depends on (Γ, κ) and N and a slightly decreasing behavior is noted for thermal conductivity with increasing Γ and N, but, overall, thermal conductivity becomes constant at intermediate-to-large Γ. The reported thermal conductivity obtained from present HPMD method, in the limit of low equilibrium perturbation, has established a reasonable agreement with that obtained from earlier known 2D numerical and experimental data. It is demonstrated that the present HPMD method is an alternative efficient tool to compute the thermal conductivity of 2D CPLCs and can be a suitable method for complete trends of complex plasmas.
Development of the Marble experimental platform at the National Ignition Facility
Authors: Olson R. E. , Murphy T. J. , Haines B. M. , Douglas M. R. , Albright B. J. , Gunderson M. A. , Kim Y. , Cardenas T. , Hamilton C. E. , Randolph R. B.
Published: October 2020

The Marble experimental platform at the National Ignition Facility (NIF) was developed to quantify the influence of heterogeneous mix on fusion burn. The platform utilizes a plastic capsule filled with a deuterated plastic foam of controlled coarseness, with tritium gas filling the voids in the foam. The capsule implosion is driven with x rays generated in an NIF Hohlraum in which the time-dependent symmetry of the implosion can be controlled via dynamic beam phasing. Importantly, the Hohlraum drive conditions can be understood via integrated 2D radiation-hydrodynamic simulations, and capsule implosions can be reliably calculated. After several years of development and experimentation, the NIF Marble platform has become successful and has produced important experimental results. The experimental results, which will be presented in a future publication by the LANL Marble team, provide the first definitive examination of the influence of heterogeneous mix on thermonuclear burn.
Non-uniform guiding magnetic field for efficiency enhancement of RBWO
Authors: Chandra Romesh , Roy Amitava , Biswas Debabrata , Sharma Archana
Published: October 2020

Relativistic backward wave oscillator (RBWO) having a resonant reflector and slow wave structure (SWS) combination has been simulated for a 400 kV peak accelerating voltage and a 4.0 kA peak electron beam current. The particle in cell simulations predict an electron beam to microwave conversion efficiency of 44% at a 3.22 GHz operating frequency. Phase space plot analysis reveals that the backstreaming of electrons from the end reflector and the end part of SWS affects the device efficiency. It was demonstrated using particles in cell simulations that with non-uniform guiding magnetic field, these backstreaming electrons do not attain synchronism with the forward wave while drifting toward the anode end and eventually rebound from the anode–cathode gap. Backstreaming of electrons reduces with increasing non-uniformity in the magnetic field. These two phenomena result in a significant enhancement in the output microwave power at a 3.22 GHz frequency and device efficiency enhances to a level of 62%. With the proposed guiding magnetic field profile, RBWO retains a larger than 52% electron beam to microwave conversion efficiency with the nominal accelerating voltage anywhere in between 400 and 600 kV and an electron beam current of 3.9–7.2 kA.
Temperature profiles, plumes, and spectra in the surface layer of convective boundary layers
Authors: McNaughton Keith G. , Chowdhuri Subharthi
Published: October 2020

We survey temperature patterns and heat transport in convective atmospheric boundary layers (CBLs). We use the word “plumes” to describe the emergent temperature patterns, in much the same way that “eddies” describe patterns of motion in turbulent flows. We introduce a two-temperature (2T) toy model to connect the cross-sectional areas of plumes to the scaling properties of temperature gradients, temperature spectra, and heat transport. We find that the half power law (z−1/2, where z is the height above the surface) form of the temperature profile reflects the change in plume cross-sectional area with height and that this is consistent with the mixed length scale required to collapse the peak regions of temperature spectra above the surface friction layer (SFL). We introduce new scaling results for temperature spectra and heat flux cospectra that extend this relationship to most of the SFLs. The spectral properties change in the bottom tenth of the SFL, where the temperature profile becomes logarithmic and temperature fluctuations increasingly display Gaussian statistics. At such small heights, the self-similarity property of the plumes reflects their randomness rather than self-similarity in the order observed above. We conclude with a general discussion, contrasting our interpretation of the role of buoyancy, as being associated with the largest structures in CBL flows, with that of Richardson [Proc. R. Soc. A 87, 354–373 (1920)], who neglected large structures and assumed that it acts locally, on the small eddies. Richardson’s ideas still inform the currently accepted, statistical fluid mechanics model of boundary-layer flows.
Invariants of the gas dynamics inside the mushroom clouds
Authors: Bogoyavlenskij Oleg
Published: October 2020

The material conservation laws are derived for the axisymmetric flows of the inviscid barotropic gas inside the mushroom clouds. The invariant functions Ψ(μ) and ΨG(μ) of an independent variable μ are constructed for any pure poloidal compressible gas flow.
Modeling of gas transport in porous medium: Stochastic simulation of the Knudsen gas and a kinetic model with homogeneous scatterer
Authors: Takata Shigeru , Hatakenaka Kisho , Hattori Masanari , Kasahara Fumiyoshi
Published: October 2020

Mass transport of the Knudsen gas in a porous medium is investigated on the basis of the kinetic theory of gases. First, the mass flow conductance is computed numerically for various porosities and solid grain sizes by stochastic particle simulations (SPS). Then, a kinetic model with a homogeneous scatterer is introduced, which contains the reference Knudsen number as the sole parameter that characterizes the collision frequency of gas molecules with the micro-structural solid surface. With the aid of the standard asymptotic analyses for small and large Knudsen numbers combined with the percolation theory, the effective reference Knudsen number is identified to reproduce the SPS results for a wide range of porosities.
Research on brushless DC motor control system based on fuzzy parameter adaptive PI algorithm
Authors: Yin Hongqiao , Yi Wenjun , Wang Kangjian , Guan Jun , Wu Jintao
Published: October 2020

As a complex system with multiple variables, nonlinearity, and strong coupling, the BLDCM (Brushless Direct Current Motor) has many problems, such as bad parameter tuning, poor adaptability, low control accuracy, and weak anti-interference ability by using the double closed loop traditional PI (Proportional Integral) control algorithm. In order to obtain good control performance, a fuzzy parameter adaptive PI algorithm based on speed loop was designed by combining fuzzy control with traditional PI control. This paper analyzes the mathematical model and operating characteristics of the BLDCM and designs a fuzzy system that takes the deviation e and deviation change rate ec of the reference speed and feedback speed as input and takes the corresponding PI adjustment parameters as output. The step response of the BLDCM at different reference speeds is analyzed. The variable speed response with the initial speed of 4000 r/min under different control algorithms and the changes in the three-phase current, back electromotive force, and electromagnetic torque in this state are compared. The results show that the designed fuzzy parameter adaptive PI algorithm based on the speed loop can make the motor have a faster response time, a smaller overshoot, and a steady-state error when the motor achieves the stable operation. The proposed algorithm also has better control effect, robustness, and stable operation under variable speed conditions.
Adaptive compensation of damping asymmetry in whole-angle hemispherical resonator gyroscope
Authors: Guo Kechen , Wu Yulie , Zhang Yongmeng , Xiao Dingbang , Wu Xuezhong
Published: October 2020

Damping asymmetry is one of the most important factors that determines the performance of the hemispherical resonator gyroscope. In this paper, the error mechanism of damping asymmetry in the Whole Angle (WA) mode is investigated, and an adaptive compensation method is proposed to eliminate the angle drift induced by the damping asymmetry. This adaptive compensation approach adopts the recursive least-squares method to identify the damping asymmetry, and the optimal parameters can be calculated through simulation. Furthermore, a self-precession method is applied to make this compensation method available for more occasions. This compensation method is able to automatically complete the compensation process without any angular input or a priori information on damping distribution. According to the experimental results, the angle-dependent bias has been reduced from 0.0316 s−1 to 0.0051 s−1 by this method. The presented method is widely applicable for gyroscopes working in the WA mode, which may be useful for further research on inertial sensors with high accuracy.
Personal Accounts of Australian Drug Discovery at the Public–Private Interface
Authors: Baell Jonathan B.
Published: October 2020

The public–private interface is a vibrant and invigorating stage for drug discovery and can allow for relatively higher risk but more rewarding research. Although adequate resourcing is a perennial challenge, persistence, optimism, and flexibility will pay dividends and can allow for a thoroughly rewarding career. In this account of chronological research experiences, selected examples are used to support this contention.
Developmental inequality and living on the margins in post-colonial Zimbabwe: the case of Musana District
Authors: Uledi Peter , Hove Godfrey
Published: October 2020

This paper explores the roots of rural poverty in Zimbabwe within the context of the role of the state and its economic and political interests over time and specific space. It traces the socio-economic and political factors that led to the impoverishment of rural areas in Zimbabwe, demonstrating that rural poverty is a colonial legacy whose roots lie in the racial ideology of the state. African Reserves were basically created as reservoirs of cheap labour for whiteowned mines and farms and emerging urban areas. They were also created to separate Africans from whites in terms of service provision at every level. However, the article further examines the role of the post-colonial government in addressing these colonial imbalances that left urban centres as islands of developments in a sea of rural underdevelopment. Using Musana District as a case study, it interrogates post-colonial state policy towards rural development and its impact in addressing the vestigial inequalities that existed between rural and urban areas. The study makes the point that despite the consistent political support it receives from rural dwellers rural development and the government’s claims that have been the cornerstone of its policies since independence, the Zimbabwean government has done little to sustainably and effectively provide basic amenities to rural areas since independence. Moreover, the paper argues that the ruling party has not only failed to contribute towards rural development but has been a direct beneficiary of the status quo as it has enabled it to maintain political stranglehold in rural areas.
Charged fluids encircling compact objects: force representations and conformal geometries
Authors: Kovář Jiří , Kojima Yasufumi , Slaný Petr , Stuchlík Zdeněk , Karas Vladimír
Published: October 2020

Charged fluids rotating around compact objects can form unique equilibrium structures when ambient large-scale electromagnetic fields combine with strong gravity. Equatorial as well as off-equatorial toroidal structures are among such figures of equilibrium with a direct relevance for astrophysics. To investigate their geometrical shapes and physical properties in the near-horizon regime, where effects of general relativity play a significant role, we commonly employ a scheme based on the energy–momentum conservation written in a standard representation. Here, we develop its interesting alternatives in terms of two covariant force representations, both based on a hypersurface projection of the energy–momentum conservation. In a proper hypersurface, space-like forces can be defined, following from a decomposition of the fluid four-acceleration. Each of the representations provides us with an insight into properties of the fluid flow, being well reflected in related conformal hypersurface geometries; we find behaviour of centrifugal forces directly related to geodesics of these conformal hypersurfaces and their embedding diagrams. We also reveal correspondence between the charged fluid flow world-lines from an ordinary spacetime, and world-lines determined by a charged test particles equation of motion in a conformal spacetime.
Photoionization of Xe 5s: angular distribution and Wigner time delay in the vicinity of the second Cooper minimum
Authors: Ganesan Aarthi , Banerjee Sourav , Deshmukh Pranawa C , Manson Steven T
Published: October 2020

The angular distribution and photoionization Wigner time delay of Xe 5s photoelectrons are studied in the region of the second Cooper minimum (SCM) using (i) the relativistic multiconfiguration Tamm–Dancoff approximation, (ii) the relativistic-random-phase approximation (RRPA) and (iii) the RRPA-with-relaxation to demonstrate how differing treatments of correlation, and the relativistic interactions, affect the results. The results of the three methods are compared with each other and with available experimental data. The comparison reveals the importance of electron correlations for which a multiconfiguration description of the initial state is essential. The spin-resolved and spin-averaged photoionization time delay results show important signatures in the region of the SCM in the Xe 5s photoionization cross-section.
Theoretical bases of hypothetical sphere-electrode detectors and practical near-sphere-electrode (semisphere-electrode and near-semisphere-electrode) detectors
Authors: Liu Manwen , Lu Shunmao , Li Zheng
Published: October 2020

In this work, one-dimensional (1D) modeling and simulations of the electric and weighting fields will be systematically carried out for hypothetical sphere-electrode detectors. Exact 1D solutions are obtained for electric and weighting fields in these detectors. Although it is impossible to realize hypothetical sphere-electrode detectors with current technologies, the theoretical work and results on them are good bases for their offspring—practical semi-sphere-electrodes (semisph-electrode) and near-semisph-electrode detectors. The great reduction in full depletion voltage and small capacitance in semisph-electrode and near-semisph-electrode detectors make them very good for applications in photon sciences (x-ray) and safeguard and homeland security (hard x-ray and gamma-ray). A practical novel structure of the three-dimensional (3D) trench electrode detector, namely a novel semisph-electrode silicon detector has been proposed as a practical example. The novel detector has a semispherical shell electrode created in a cuboidal unit cell. It will overcome the traditional 3D-electrode detector deficiencies in electrical performance such as the asymmetrical electric field distribution. Through a computer-aided design tool, 3D modeling and electrical characteristics, simulation of a semispherical electrode silicon detector has been obtained, such as electric field distributions, electron concentration distribution, and full depletion voltage