bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of Personal Protective Equipment - a complex issue of multi-criteria analysis
Authors: Haraga Armand-Radu , Cazac Alin-Marian , Lohan Nicoleta-Monica , Corăbieru Anişoara , Toma Stefan-Lucian
Published: August 2021

It is known the fact that in both the Member States of the European Union and the United States, the provision of Personal Protective Equipment (PPE) to workers who are carrying out their activity in different sectors is done in accordance with existing legislation and regulations specific to each state. However, choosing a suitable PPE for a particular workplace is a difficult task to perform given that there are a variety of PPE on the market that perform, in different ways these functions: to prevent an accident - from the same place of work. to protect the health and safety of workers and to minimize damage from any possible accident. Comparing the alternatives, in order to find the most favourable protective equipment specific to a particular workplace, is a complex multi-criteria decision problem that sometimes is difficult to solve. In this paper we approached a method of multi-criteria analysis of the decision, respectively we applied a Analytical Hierarchy Process (AHP) to select PPE -favourable to a certain job: mechanical locksmith. Our work allowed us to find the dominant criteria and the critical factors in the products evaluation, multi-criteria evaluation AHP of employees’ requirements, regarding PPE and ergonomic aspects.
Surveying workers perceptions in the automotive industry - a preventive tool for monitoring OSH measures
Authors: Neag Nicoleta Paula , Gaureanu Alin , Calciu Nicoleta-Lavinia , Tamasila Matei
Published: August 2021

In an efficient OSH management system, it is necessary to approach continuous improvement, being recommended the PDCA system (Plan Do Check Act). In Romania, there is well-developed legislation, who establishes measures and actions in the field of OSH. The companies comply by creating an implementation plan, but most of them remain at this stage, without verifying the degree of implementation, with adaptation/updating of the measures. In this paper, we highlight some reference elements that can be periodically probed, so that the OSH management system can have a prompt and justified improvement reaction. The mode of obtaining this information regarding the implemented measures can be achieved through a periodic questionnaire that diagnoses two relevant aspects: 1. workers’ perceptions - which assess the implementation method; 2. the consequences/accidents - that assess the efficiency of the measures and their application/implementation. The two key elements (perception and consequences) will be used by the questionnaire responding workers after the implementation stage. The profile of these respondents is considered, and depending on their age, function, and level of education, the new applicable measures can be dimensioned. Only through continuous, monitored, and adapted improvement can the most effective measures be implemented, so that prevention fulfils its fundamental purpose, to contribute to the predictability and sustainability of an efficient automotive enterprise.
Study on the application of the QEC (Quick Exposure Check) on the ergonomic risks assessment in the industrial field
Authors: Ispăsoiu Adrian , Milosan Ioan , Senchetru Dorin , Machedon-Pisu Teodor , Ispăsoiu Ana Maria Florina , Meiţă Cristina
Published: August 2021

In Romania there are approximately 200,000 employees in the automotive industry, ranking 4th in the EU, after Germany, France and Poland. Many workers in these industries complain of musculoskeletal disorders caused by the high pace of work, awkward positions, handling of masses, etc., often being cumulated. It is therefore essential that these risks related to ergonomics are correctly identified, assessed and treated. The Quick Exposure Check (QEC) is an advanced exposure assessment method that combines observational assessment and self-reporting. This paper presents an applied study of the QEC methodology, a technique based on questions that will be answered by both the observer and the evaluated worker. The research analysed the activity of manually transferring metal parts (components from the automotive industry) from a trolley on a conveyor belt for processing and, vice versa, taking the processed parts from a conveyor belt and placing them on a trolley, because these activities generate many risks to workers’ health. Analysing the results of the evaluation of the ergonomic risks generated by incorrect and / or awkward positions during the activities, using the QEC method, it is found that there are some areas of the body that are much affected during these activities.
The joy of teaching and learning in academia – teachers’ perspectives from three countries
Authors: Mag Alina Georgeta , Sinfield Sandra , Burns Tom , Abegglen Sandra
Published: August 2021

All over the world, the educational landscape has changed dramatically over the last year, impacting the way we teach and learn. It is time for reflecting and searching for new ways to support each other, during these pandemic times and beyond; time to co-construct creative partnerships and to innovate new ways to co-create. Change is an inevitable part of teaching and learning but the adaptations currently required are of unprecedented scale. How can we teach and learn with joy in today’s academia? How can we support each other, as teachers, in more creative ways? These two reflective questions were at the base of the study, which was conducted by university teachers from three countries: “Lucian Blaga” University of Sibiu, Romania; London Metropolitan University, United Kingdom; and University of Calgary, Canada. The methods used included interviews, focus groups and free writing with colleagues in each university. Findings revealed the challenges faced by each participant due to the emotional pressure caused in these supercomplex times, and the struggle to bring joy of teaching and learning in creative ways. This small ethnographic project reveals a need to shift our thinking about emotions and how we may facilitate the greatest success of all our students, by continually inventing new solutions and teaching with enthusiasm.
Recent Advances on Annulation Reactions with Allyl and Propargyl Sulfonium Salts
Authors: Li Jun-Long , Li Qing-Zhu , Zou Wen-Lin , Jia Zhi-Qiang
Published: August 2021

Allyl and propargyl sulfonium salts are readily available reagents that have recently emerged as versatile building blocks for the assembly of cyclic skeletons. As an alternative to classical sulfonium salts, allyl and propargyl sulfonium salts can be converted into the corresponding vinyl sulfur ylide or allenic sulfonium salt intermediates that contain diverse nucleophilic or electrophilic reactive positions, thereby enabling a great variety of annulation reactions. In this short review, we provide a comprehensive overview of the recent developments in this growing field by summarizing annulation reactions involving allyl and propargyl sulfonium salts.

1 Introduction

2 Annulations with Allyl Sulfonium Salts

3 Annulations with Propargyl Sulfonium Salts

4 Conclusion
The Bethesda System for Reporting Thyroid Cytopathology: Validating at Tribhuvan University Teaching Hospital
Authors: Acharya Kunjan , Shrivastav Shreya , Triipathi Prashant , Gyawali Bigyan Raj , Kharel Bijaya , Baskota Dharma Kanta , Sinha Pallavi
Published: August 2021

Introduction Fine needle aspiration cytopathology (FNAC) is widely used for the stratification of thyroid nodules.

Objective The objective of the present study is to validate FNAC reporting based on The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) at our institution and to calculate the risk of malignancy in each category.

Methods This was a descriptive cross-sectional study conducted jointly at the Department of Ear, Nose and Throat and at the Department of Pathology for a period of 1.5 years (May 2018 to November 2018). All cases presenting with thyroid swelling in the outpatient department were investigated with ultrasonography (USG) of the neck, thyroid function test, and FNAC. All FNAC reporting was done according to TBSRTC.

Results A total of 134 thyroidectomies were performed during the study period. The female to male ratio was 5.3:1. The age ranged from 11 to 74 years old. with a mean age of 51 years old. The FNAC has a specificity of 84.9%, a sensitivity of 89.4%, a positive predictive value of 86.4%, a negative predictive value of 88.2%, and an accuracy of 87.3% in detecting thyroid cancer. The implied risk of malignancy (ROM) in Bethesda II, III, IV, V and VI is 11.7%, 25%,40%,76.6% & 96%, respectively.

Conclusion The four studied categories had a ROM comparable to other studies, except for the Bethesda III category. Further studies with larger sample sizes and with the use of USG guidance for the aspiration from the thyroid swelling may give better results by reducing the number of false negative and false positive cases.
Transarterial Chemoembolization in Unresectable Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis: A Tertiary Care Center Experience
Authors: Patidar Yashwant , Mukund Amar , Sarin Shiv K. ,   Basavaraj
Published: August 2021

Background Portal vein tumor thrombosis (PVTT) is a common complication of hepatocellular carcinoma (HCC) occurring in 30 to 40% of cases. The presence of PVTT in HCC is regarded as an advanced disease that confers poor prognosis and survival. Transarterial chemoembolization (TACE) has traditionally been considered to be contraindicated in cases of PVTT, due to the risk of hepatic infarction, and further deteriorate liver function. We evaluated safety, technical efficacy, and outcomes of TACE in HCC with PVTT.

Methods From search results of the hospital database, out of 652 patients who underwent TACE for HCC, 73 patients of HCC with PVTT were retrospectively evaluated. Post-TACE tumor response by computed tomography (CT)/magnetic resonance imaging (MRI) imaging as per modified response evaluation criteria in solid tumors (mRECIST) criteria, if any occurrence of acute hepatic failure was assessed. Prognostic factors influencing survival were also determined.

Results In our study population, the mean age of the patients was 58 years. The 12- and 24-month survival rates were 59 and 14%, respectively, with an overall median survival of 12.3 months. A total of 58.9% patients had branch portal vein tumor thrombus and 41.1% had tumor thrombus in the main portal vein. We did not encounter any mortality or acute liver failure following TACE in a 30-day period. Both univariate and multivariate analysis revealed Child–Pugh score (p = 0.01) and the extent of tumoral thrombus (p 0.004) as a significant prognostic factor. Patients with branch PVTT, no ascites, and Child–Pugh A had better survival than those having main portal vein tumor thrombus, ascites, and Child–Pugh B.

Conclusion Our study concluded that TACE can achieve good disease control and improved survival in HCC with portal vein invasion despite being considered as a relative contraindication. Technical expertise, selection of patients, such as superselective catheterization and preserved liver function, are the key factors for a safe therapeutic procedure. Child–Pugh score and extent of portal vein invasion were the significant prognostic factors determining survival.
Magnetic Resonance Imaging of Uterine Cervix: A Pictorial Essay
Authors: Gala Foram B. , Gala Kunal B. , Gala Bharat M.
Published: August 2021

Uterine cervix is the lower constricted part of uterus which is best evaluated by magnetic resonance imaging (MRI) due to its higher soft tissue and contrast resolution. The cervical cancer is a common gynecological cancer causing much morbidity and mortality especially in developing countries. Cervical carcinomas mainly occurs in reproductive age group with prognosis mainly depending on the extent of disease at the time of diagnosis, hence it is important to identify these cancerous lesions early and stage them accurately for optimal treatment. In this article, we will review the following: (1) the normal MRI anatomy of uterine cervix; (2) MRI protocol and techniques in evaluation of cervical lesions; (3) imaging of spectrum of various congenital abnormalities and pathologies affecting uterine cervix which ranges from congenital abnormalities to various benign lesions of cervix like nabothian cysts, tunnel cysts, cervicitis, cervical fibroid, and, lastly, endometriosis which usually coexists with adenomyosis; the malignant lesions include carcinoma cervix, adenoma malignum or direct extension from carcinoma endometrium or from carcinoma of vagina; (4) Accurately stage carcinoma of cervix using FIGO classification (2018); and (5) posttreatment evaluation of cervical cancers. MRI is the most reliable imaging modality in evaluation of various cervical lesions, identification of cervical tumors, staging of the cervical malignancy, and stratifying patients for surgery and radiation therapy. It also plays an important role in detection of local disease recurrence.
Decoherence mitigation by real-time noise acquisition
Authors: Braunbeck G. , Kaindl M. , Waeber A. M. , Reinhard F.
Published: August 2021

We present a scheme to neutralize the dephasing effect induced by classical noise on a qubit. The scheme builds upon the key idea that this kind of noise can be recorded by a classical device during the qubit evolution, and that its effect can be undone by a suitable control sequence that is conditioned on the measurement result. We specifically demonstrate this scheme on a nitrogen-vacancy center that strongly couples to current noise in a nearby conductor. By conditioning the readout observable on a measurement of the current, we recover the full qubit coherence and the qubit's intrinsic coherence time T2. We demonstrate that this scheme provides a simple way to implement single-qubit gates with an infidelity of 10−2 even if they are driven by noisy sources, and we estimate that an infidelity of 10−5 could be reached with additional improvements. We anticipate this method to find widespread adoption in experiments using fast control pulses driven from strong currents, in particular, in nanoscale magnetic resonance imaging, where control of peak currents of 100 mA with a bandwidth of 100 MHz is required.
Quantifying dynamical and structural invariance in a simple molten salt model
Authors: Knudsen Peter A. , Niss Kristine , Bailey Nicholas P.
Published: August 2021

Recent experimental results for the structure in the ionic liquid PYR14+TFSI− have shown invariance in the main structure factor peak along curves of equal electrical conductivity [Hansen et al., Phys. Chem. Chem. Phys. 22, 14169 (2020)]. The charge peak decreases slightly with increasing temperature at fixed conductivity, however. For simple liquids, curves with invariant dynamics and structure, known as isomorphs, can be identified as configurational adiabats. While liquids with strong-Coulomb interactions do not have good isomorphs, ionic liquids could be an intermediate case with approximate isomorphs along which some aspects of structure and dynamics are invariant. We study a simple molten salt model using molecular dynamics simulations to test this hypothesis. Simple measures of structure and dynamics are investigated along with one transport property, the shear viscosity. We find that there is a substantial degree of invariance of the self-intermediate scattering function, the mean square displacement, and the viscosity along configurational adiabats over a wide range of densities for the three adiabats simulated. The density range studied is more than a factor of two and extends from the strong-Coulomb regime at low densities to the weak-Coulomb regime at high densities. The structure is not invariant over the full range of density, but in the weak-Coulomb regime, we see behavior similar to that seen experimentally over density changes of order 15%. In view of the limited structural invariance but substantial dynamical invariance, we designate the configurational adiabats as isodynes.
Spin contribution to the instability of THz plasma waves
Authors: Liu Chenxiao , Zhang Liping , Feng Jiangxu
Published: August 2021

When the boundary conditions of the source and drain are asymmetric, the plasma waves may become unstable in the channel of a field effect transistor (FET). We use the quantum magnetohydrodynamic model to study the influence of the quantum Bohm potential, Fermi statistical pressure, and electron spin effects on the stability of THz plasma waves propagating perpendicular to the magnetic field in the FET. A dispersion equation governing the THz plasma oscillation is obtained. Numerical results have shown that the presence of spin effects has enlarged the instable range of β, enhanced the instability increment, and made the frequency of THz plasma waves larger. The research shows that nanometer FETs with spin effects have advantages in realizing practical terahertz radiation.
Mathematical modeling of electrokinetic transport through endothelial-cell glycocalyx
Authors: Dey Bibaswan , Raja Sekhar G. P.
Published: August 2021

The motivation for the present study is to understand the role of the endothelial-cell glycocalyx layer (EGL) toward the transport of charged or uncharged blood-borne solutes (nutrients, ions, drug nanoparticles, etc.) from the bloodstream inside the blood vessels. Various experimental observations prevail that EGL holds negative charges in its skeleton, and the corresponding electric double layer interacts with the blood plasma (treated as an electrolyte). The biphasic mixture theory-based momentum equations modified with the electrokinetic body forces are adopted to model EGL. On the other hand, the Stokes equation modified with the Coulomb body force is used to govern the flow of plasma. This study is analytical where a standard perturbation approach is deployed in the governing momentum balance equations which are subsequently solved by Fourier series expansion analysis. In the next part of the study, the diffusion-convection equation is adopted in the plasma region to study the blood-borne solute transport from plasma to EGL under the electrokinetic influence. Using a similarity method, the solute concentration within a thin mass transfer boundary layer close to the EGL interface is obtained. The present study reveals that a higher magnitude of both interface potential and charge density promotes the volumetric flow rate of plasma and the interface skin friction. Moreover, increased interface potential and charge density show the enhancement of solute transport from the plasma region to the EGL. Finally, this study finds criteria to identify a healthy EGL.
Theory of the effect of external stress on the activated dynamics and transport of dilute penetrants in supercooled liquids and glasses
Authors: Mei Baicheng , Schweizer Kenneth S.
Published: August 2021

We generalize the self-consistent cooperative hopping theory for a dilute spherical penetrant or tracer activated dynamics in dense metastable hard sphere fluids and glasses to address the effect of external stress, the consequences of which are systematically established as a function of matrix packing fraction and penetrant-to-matrix size ratio. All relaxation processes speed up under stress, but the difference between the penetrant and matrix hopping (alpha relaxation) times decreases significantly with stress corresponding to less time scale decoupling. A dynamic crossover occurs at a critical “slaving onset” stress beyond which the matrix activated hopping relaxation time controls the penetrant hopping time. This characteristic stress increases (decreases) exponentially with packing fraction (size ratio) and can be well below the absolute yield stress of the matrix. Below the slaving onset, the penetrant hopping time is predicted to vary exponentially with stress, differing from the power law dependence of the pure matrix alpha time due to system-specificity of the stress-induced changes in the penetrant local cage and elastic barriers. An exponential growth of the penetrant alpha relaxation time with size ratio under stress is predicted, and at a fixed matrix packing fraction, the exponential relation between penetrant hopping time and stress for different size ratios can be collapsed onto a master curve. Direct connections between the short- and long-time activated penetrant dynamics and between the penetrant (or matrix) alpha relaxation time and matrix thermodynamic dimensionless compressibility are also predicted. The presented results should be testable in future experiments and simulations.
Late-time description of immiscible Rayleigh–Taylor instability: A lattice Boltzmann study
Authors: Liang Hong , Xia Zhenhua , Huang Haowei
Published: August 2021

In this paper, the late-time description of immiscible Rayleigh–Taylor instability (RTI) in a long duct is numerically investigated over a comprehensive range of the Reynolds numbers (1≤Re≤10 000) and Atwood numbers (0.05≤A≤0.7) using the mesoscopic lattice Boltzmann method on high-resolution meshes. It is found that the instability with a high Reynolds number undergoes a sequence of distinguishing stages, which are termed as the linear growth, saturated velocity growth, reacceleration and chaotic development stages. The dynamics of the spike and bubble from the saturated velocity growth stage to the final chaotic development stage are studied, and the growth rates of the spike and bubble during the late-time chaotic stage are analyzed quantitatively by using five popular statistical methods. When Re is gradually reduced, some later stages, such as the chaotic and reacceleration stages, cannot successively be reached and the phase interfaces in the evolutional process become relatively smooth. The influence of A on the late-time RTI development at a high Reynolds number is also examined. It is shown that the late-time growth rate of the spike will overall increase with A, while the growth rate of the bubble is approximately constant, being around 0.0215.
Indirect light absorption model for highly strained silicon infrared sensors
Authors: Roisin Nicolas , Brunin Guillaume , Rignanese Gian-Marco , Flandre Denis , Raskin Jean-Pierre
Published: August 2021

The optical properties of silicon can be greatly tuned by applying strain and opening new perspectives, particularly in applications where infrared is key. In this work, we use a recent model for the indirect light absorption of silicon and include the effects of tensile and compressive uniaxial strains. The model is based on material properties such as the bandgap, the conduction and valence band density-of-states effective masses, and the phonon frequencies, which are obtained from first principles including strain up to ±2% along the [110] and [111] directions. We show that the limit of absorption can increase from 1.14 (1.09) to 1.35 μm (0.92 eV) under 2% strain and that the absorption increases by a factor of 55 for the zero-strain cutoff wavelength of 1.14 μm when a 2% compressive strain is applied in the [110] direction. We demonstrate that this effect is mainly due to the impact of strain on the electronic bandgaps of silicon, directly followed by the valence band density-of-states effective mass.
Double-filter high-resolution soft x-ray tomographic diagnostic for investigating electron acceleration in TS-6 reconnection merging experiments
Authors: Xiang Junguang , Takeda Shinjiro , Cai Yunhan , Tanabe Hiroshi , Cao Qinghong , Tanaka Haruaki , Ono Yasushi
Published: August 2021

An innovative tangential-view soft x-ray (SXR) tomographic imaging measurement was developed on the TS-6 spherical tokamak merging device as a key diagnostic for investigating the mechanism of electron acceleration. In order to measure SXR with different energy ranges, two micro-channel plates (MCPs) are, respectively, installed in two vacuum chambers, which are equipped with different filters. Especially designed lenses and fiber bundles serve as an optical system to transfer images from phosphor plates of MCPs to a high speed imaging system. This design also enables us to simultaneously measure two images appearing on phosphor plates of MCPs by just one high speed imaging system. The temporal and spatial resolution of this diagnostic can be up to 5 µs and 4 mm, respectively, at present. The tomographic method based on the Phillips–Tikhonov regularization is employed to reconstruct line-integrated images into the local emissivity of SXR, which reflects the spatial distribution of high-energy electrons. Owing to this diagnostic, we successfully measured SXR emitted from the downstream region of magnetic reconnection in TS-6 merging experiments for the first time. The energy range of SXR turned out to be higher than 100 eV but lower than 400 eV.
Change in ionization potential of magnesium tin oxide films before and after photochromism
Authors: Suzuki Yutaro , Takaki Hidetaka , Inoue Shuhei , Matsumura Yukihiko
Published: August 2021

Magnesium-tin oxide (MTO) became a cell storage material after strong UV irradiation, and the appearance of the photochromic phenomenon was the sign of initiation of such a function. This phenomenon is not an independent behavior occurring in magnesium-tin oxide films, but we found that the phenomenon occurred in the interface between the MTO layer and indium tin oxide layer prepared under the MTO layer. To clarify this phenomenon, analysis of the MTO layer is the key issue and investigation under the environmental condition is required. The photochromic color change does not reproduce by excess heating treatment. In this paper, we focused on the change in the ionization potential of the MTO film before/after the reversible color change and irreversible erase, and to achieve this experiment, we constructed a novel photoelectron yield spectrometer and measured the ionization potential of a magnesium tin oxide film.
Valence shell photoelectron angular distributions and vibrationally resolved spectra of imidazole: A combined experimental–theoretical study
Authors: Patanen M. , Abid A. R. , Pratt S. T. , Kivimäki A. , Trofimov A. B. , Skitnevskaya A. D. , Grigoricheva E. K. , Gromov E. V. , Powis I. , Holland D. M. P.
Published: August 2021

Linearly polarized synchrotron radiation has been used to record polarization dependent valence shell photoelectron spectra of imidazole in the photon energy range 21–100 eV. These have allowed the photoelectron angular distributions, as characterized by the anisotropy parameter β, and the electronic state intensity branching ratios to be determined. Complementing these experimental data, theoretical photoionization partial cross sections and β-parameters have been calculated for the outer valence shell orbitals. The assignment of the structure appearing in the experimental photoelectron spectra has been guided by vertical ionization energies and spectral intensities calculated by various theoretical methods that incorporate electron correlation and orbital relaxation. Strong orbital relaxation effects have been found for the 15a′, nitrogen lone-pair orbital. The calculations also predict that configuration mixing leads to the formation of several low-lying satellite states. The vibrational structure associated with ionization out of a particular orbital has been simulated within the Franck–Condon model using harmonic vibrational modes. The adiabatic approximation appears to be valid for the X 2A″ state, with the β-parameter for this state being independent of the level of vibrational excitation. However, for all the other outer valence ionic states, a disparity occurs between the observed and the simulated vibrational structure, and the measured β-parameters are at variance with the behavior expected at the level of the Franck–Condon approximation. These inconsistencies suggest that the excited electronic states may be interacting vibronically such that the nuclear dynamics occur over coupled potential energy surfaces.
Blockage formation in water-flooding heavy oil reservoirs: The distribution rule and the scaling mechanism
Authors: Jiang Haizhuang , Kang Wanli , Zhou Bobo , Wang Fang , Yang Hongbin , Li Zhe , He Yingqi , Shao Yuxuan , Sarsenbekuly Bauyrzhan , Gabdullin Maratbek , Turtabayev Sarsenbek
Published: August 2021

Blockage is a common problem in the development of water-flooding reservoirs. The key to solve this problem is to determine the composition and distribution rules of the blockage. In this work, the location distribution and components of blockage were analyzed by one-dimensional (1D) and two-dimensional (2D) cores, and x-ray diffraction and differential weight methods. The blockage formation mechanism was also studied. The 1D experimental results show that the blocking locations of the inlet and outlet ends are 3/10 and 8/10, respectively (1D core is divided into 10 equidistant sections; “3/10” refers to the three sections from the inlet end and “8/10” refers to the two sections from the outlet end). The blockage near the inlet is mainly composed of inorganic scale, which is formed by a combination of the carbonate and coarse sand particles. However, the blockage near the outlet is mainly composite scale, which is formed by the fine particles and inorganic scale with heavy oil. In addition, the water sensitivity with clay leads to the decrease in permeability. This work provides a theoretical and scientific basis for the development of technology to effectively prevent reservoir blockage.
Predicting large-scale pool fire dynamics using an unsteady flamelet- and large-eddy simulation-based model suite
Authors: Domino Stefan P. , Hewson John , Knaus Robert , Hansen Mike
Published: August 2021

A low-Mach, unstructured, large-eddy-simulation-based, unsteady flamelet approach with a generalized heat loss combustion methodology (including soot generation and consumption mechanisms) is deployed to support a large-scale, quiescent, 5-m JP-8 pool fire validation study. The quiescent pool fire validation study deploys solution sensitivity procedures, i.e., the effect of mesh and time step refinement on capturing key fire dynamics such as fingering and puffing, as mesh resolutions approach O(1) cm. A novel design-order, discrete-ordinate-method discretization methodology is established by use of an analytical thermal/participating media radiation solution on both low-order hexahedral and tetrahedral mesh topologies in addition to quadratic hexahedral elements. The coupling between heat losses and the flamelet thermochemical state is achieved by augmenting the unsteady flamelet equation set with a heat loss source term. Soot and radiation source terms are determined using flamelet approaches for the full range of heat losses experienced in fire applications including radiative extinction. The proposed modeling and simulation paradigm are validated using pool surface radiative heat flux, maximum centerline temperature location, and puffing frequency data, all of which are predicted within 10% accuracy. Simulations demonstrate that under-resolved meshes predict an overly conservative radiative heat flux magnitude with improved comparisons as compared to a previously deployed hybrid Reynolds-averaged Navier–Stokes/eddy dissipation concept-based methodology.
Electro-thermo-convection in power-law fluids within a square enclosure with an inner cylinder
Authors: Ma Ben , Wang Lei , He Kun , Li Dinggen
Published: August 2021

This paper investigates the electro-thermo-convection of power-law non-Newtonian fluids between a square enclosure and inner cylinder subjected to the simultaneous actions of external thermal and electric fields via lattice Boltzmann method. We concentrate on the flow structure transition, heat transfer efficiency as well as the bifurcation criteria concerning the electric Rayleigh number T for various power index 0.6≤n≤1.4. In addition, in order to comprehensively examine the impacts of buoyancy, two different Rayleigh numbers (Ra=103,105) are considered, corresponding to the weak and strong buoyancy. The cases for Newtonian fluids are used as the basic result to compare with the non-Newtonian cases. Based on the simulations, it is found that the flow motion and bifurcation criteria depend strongly on the power-law index. Specifically, the shear-shinning characteristic decreases the bifurcation threshold and exhibits a smaller hysteresis loop compared with Newtonian fluid, and the opposite effect and more evolution details about the transformation of charge void region with different shapes can be captured for shear-thickening characteristic. Additionally, the flow motions with stronger thermal convection illustrate more complex bifurcation diagrams and hysteresis loops due to the cooperation and competition between the buoyant and Coulomb forces, while it is not obvious for shear-thickening fluids.
Integral measures of the zero pressure gradient boundary layer over the Reynolds number range ≤Rτ<∞
Authors: Cantwell Brian J.
Published: August 2021

A recently developed mixing length model of the turbulent shearing stress has been shown to generate a universal velocity profile that provides an accurate approximation to incompressible pipe flow velocity profiles over a wide Reynolds number range [B. J. Cantwell, “A universal velocity profile for smooth wall pipe flow,” J. Fluid Mech. 878, 834–874 (2019)]. More recently, the same profile was shown to accurately approximate velocity profiles in channel flow, the zero pressure gradient boundary layer, and the boundary layer in an adverse pressure gradient [M. A. Subrahmanyam, B. J. Cantwell, and J. J. Alonso, “A universal velocity profile for turbulent wall flows,” AIAA Paper No. 2021-0061, 2021 and M. A. Subrahmanyam, B. J. Cantwell, and J. J. Alonso, “A universal velocity profile for turbulent wall flows including adverse pressure gradient boundary layers,” J. Fluid Mech. (unpublished) (2021)] The universal velocity profile is uniformly valid from the wall to the free stream at all Reynolds numbers from zero to infinity. At a low Reynolds number, the profile approaches the laminar channel/pipe flow limit. The primary measure of the Reynolds number used in this work is the friction Reynolds number Rτ=uτδ/ν. It is a little unusual to use Rτ for the boundary layer since it requires that the velocity profile be cutoff using an arbitrarily defined overall boundary layer thickness, δ. Because of the slow approach of the velocity to the free stream, different conventions used to define the thickness lead to different values of Rτ assigned to a given flow. It will be shown in this paper that, through its connection to channel/pipe flow, the universal velocity profile can be used to define a practically useful, unambiguous, measure of overall boundary layer thickness, called here the equivalent channel half height, δh. For Rτ>≈5000, the universal velocity profile defines a Reynolds number independent shape function that can be used to generate explicit expressions for the infinite Reynolds number behavior of all the usual integral boundary layer measures; displacement thickness, momentum thickness, energy thickness, overall boundary layer thickness, and skin friction. The friction coefficient Cf(Rδ2) generated by the universal velocity profile accurately approximates data over a wide range of momentum thickness Reynolds numbers collected by Nagib et al. [“Can we ever rely on results from wall-bounded turbulent flows without direct measurements of wall shear stress?,” AIAA Paper No. 2004-2392, 2004]. The universal velocity profile is used to integrate the von Kaŕmań boundary layer integral equation [T. von Kármán, “Uber laminaire und turbulente reibung,” Z. Angew. Math. Mech. 1, 233–252 (1921)] in order to generate the various thicknesses and friction velocity as functions of the spatial Reynolds number, Rx=uex/ν.
Edward E. O'Brien contributions to reactive-flow turbulence
Authors: Dopazo Cesar , Givi Peyman , Ladeinde Foluso
Published: August 2021

Professor Edward Ephraim O'Brien (“Ted”) has made lasting contributions to the theory and modeling of scalar mixing and reaction in turbulent flows. With a doctoral dissertation at The Johns Hopkins University in 1960, entitled “On the Statistical Behavior of a Dilute Reactant in Isotropic Turbulence,” supervised by the legend Stanley Corrsin, and in the company of notable pioneer of turbulence, John Leask Lumley, Ted's academic training propelled him through a prolific career. In the opening article of this Special Issue, we provide a review of some of Ted's contributions. First, a summary is presented of his work on the examination of the failure of the cumulant discard approximation for the scalar mixing. This is followed by a highlight of his impacts on other spectral theories of turbulence including Kraichnan's direct interaction approximation. His contributions to more modern theoretical/computational description of reactive turbulence are discussed next, including the transported probability density function (pdf) formulation, scalar-gradient pdf transport equation, scalar interfaces, and the filtered density function. Finally, some of his research on Direct Numerical Simulation of compressible turbulence is reviewed.
Quantifying the compressibility of complex networks
Authors: Lynn Christopher W. , Bassett Danielle S.
Published: August 2021

Significance

Real-world networks are complex, comprising vast webs of interconnected elements performing a diverse array of social and biological functions. Common among many networks, however, is the pressure to be efficiently compressed—either in the brain or in the genetic code. But just as files on a computer can be compressed to differing degrees, what makes one network more compressible than another? To answer this question, we adapt tools from information theory to quantify the compressibility of a network. Studying real-world and model networks, we find that hierarchical organization—with tight clustering and heterogeneous degrees—increases compressibility, enabling compressed representations across scales. Generally, our framework provides an information-theoretic method for investigating the interplay between network structure and compression.
How multisensory neurons solve causal inference
Authors: Rideaux Reuben , Storrs Katherine R. , Maiello Guido , Welchman Andrew E.
Published: August 2021

Significance

We perceive our environment through multiple independent sources of sensory input. The brain is tasked with deciding whether multiple signals are produced by the same or different events (i.e., solve the problem of causal inference). Here, we train a neural network to solve causal inference by either combining or separating visual and vestibular inputs in order to estimate self- and scene motion. We find that the network recapitulates key neurophysiological (i.e., congruent and opposite neurons) and behavioral (e.g., reliability-based cue weighting) properties of biological systems. We show how congruent and opposite neurons support motion estimation and how the balance in activity between these subpopulations determines whether to combine or separate multisensory signals.
Conformations of voltage-sensing domain III differentially define NaV channel closed- and open-state inactivation
Authors: Angsutararux Paweorn , Kang Po Wei , Zhu Wandi , Silva Jonathan R.
Published: August 2021

Voltage-gated Na+ (NaV) channels underlie the initiation and propagation of action potentials (APs). Rapid inactivation after NaV channel opening, known as open-state inactivation, plays a critical role in limiting the AP duration. However, NaV channel inactivation can also occur before opening, namely closed-state inactivation, to tune the cellular excitability. The voltage-sensing domain (VSD) within repeat IV (VSD-IV) of the pseudotetrameric NaV channel α-subunit is known to be a critical regulator of NaV channel inactivation. Yet, the two processes of open- and closed-state inactivation predominate at different voltage ranges and feature distinct kinetics. How inactivation occurs over these different ranges to give rise to the complexity of NaV channel dynamics is unclear. Past functional studies and recent cryo-electron microscopy structures, however, reveal significant inactivation regulation from other NaV channel components. In this Hypothesis paper, we propose that the VSD of NaV repeat III (VSD-III), together with VSD-IV, orchestrates the inactivation-state occupancy of NaV channels by modulating the affinity of the intracellular binding site of the IFMT motif on the III-IV linker. We review and outline substantial evidence that VSD-III activates in two distinct steps, with the intermediate and fully activated conformation regulating closed- and open-state inactivation state occupancy by altering the formation and affinity of the IFMT crevice. A role of VSD-III in determining inactivation-state occupancy and recovery from inactivation suggests a regulatory mechanism for the state-dependent block by small-molecule anti-arrhythmic and anesthetic therapies.
Development of interactive learning multimedia for mathematics subjects for grade 5 elementary schools
Authors: Firmansyah F H , Sari I P , Permana F C , Rinjani D
Published: August 2021

The learning process during a pandemic requires teachers to be more interactive in making online learning media. The government has designed the Covid Emergency Curriculum, which is that educational units in their current condition can choose one of the several components needed in the learning process, namely still referring to the national curriculum, using the emergency curriculum, or making curriculum simplification independently. For curriculum simplification, only the main material in learning activities needs to be conveyed, while for practice it can be independently or through an application media. This study aims to create an augmented reality-based learning media on geometry in mathematics subjects for grade 5 elementary school. This media can make it easier for students to understand the shapes with augmented reality and there is a learning video feature that also explains the material presented by the teacher. With the black box white box method, the application is developed by adjusting the curriculum simplification planned by the government. Features in the application include objectives and materials, learning videos, augmented reality simulations and integrated with Google Classroom as a learning evaluation platform. The results of this research are digital applications that can be accessed from the web or android applications.
Batik AR ver.1.0: Augmented Reality application as gamification of batik design using waterfall method
Authors: Sobandi B , Wibawa S C , Triyanto T , Syakir S , Pandanwangi A , Suryadi S , Nursalim A , Santosa H
Published: August 2021

During the Covid-19 pandemic, it’s time to implement asynchronous learning. The problem is, elementary school students have difficulty learning cultural arts, especially batik design. This study aims to create an application base on augmented reality (AR) with batik design content that can be used to introduce batik design as cultural art to elementary school students. The method used in developing this application is a waterfall which consists of (1) feasibility study, (2) requirements, (3) System design, (4) Encoding, (5) Testing system, (6) Acceptance Test. The results of this study were the validators rated more than 85% of media validation consisting of the quality of visual and auditory perceptions, ease of interaction, ease of interaction, and ease of use, while user responses consisted of 80% efficiency, 85% usability, 78% cognitive absorption, and enjoyment. 87%. This implies that the AR application can provide benefits for students who learn cultural sessions, especially batik design.
In-service teachers’ perception on implementing realistic mathematics education approach in their best practices
Authors: Mariana N , Sholihah S A , Riski R , Rahmawati I , Wiryanto W , Indrawati D , Budiyono B
Published: August 2021

This paper aims to portray elementary teachers’ perception of implementing the Realistic Mathematics Education (RME) approach in their best practice after training in a series of RME workshops. The perceptions captured in the study include (1) teachers’ confidence in understanding RME and its implementation in their best practices; (2) RME criteria, which teachers found most challenging during the planning and the implementation. The subject of this study is 296 elementary teachers who have attended the training. The workshop series provided RME materials, simulation during the workshop, implementation in teachers’ best practices, and the workshop to discuss their experience. There are two findings in this study. Firstly, most teachers have a better understanding of RME characteristics. However, most teacher believe that the RME approach can be applied most mathematical topics. They felt confident in implementing the RME approach in their best practices. Secondly, teachers found that the most challenging when planned the RME lesson was finding suitable media related to mathematics topics. Moreover, during the implementation, teachers found it most challenging to lead students to formal mathematics. These results suggest that the most impactful workshop is better, followed by best practices and participants’ reflection afterward.
The mathematical self-efficacy instruments for elementary school students
Authors: Yuliyanto A , Turmudi T , Putri H E , Muqodas I , Rahayu P
Published: August 2021

Mathematical self-efficacy is a person’s belief in his ability to solve mathematical problems received. The output of this study is to produce an instrument that can measure MSE comprehensively and accountability. Research and Development (R&D) was chosen as the research method. The sample selection was done by purposive sampling involving 20 students of the 6th-grade elementary school in Karawang. Based on the development and analysis of aspects and indicators showing aspects of MSE including personal experiences in learning mathematics, the experiences of the others about learning mathematics, verbal persuasion after doing mathematics, and psychological indexes when doing mathematics problems. Each of these four aspects consists of three indicators namely confidence can complete difficult, varied, and challenging tasks. Based on the results of testing, the validity and reliability obtained all items have sufficient validity (rxy = 0.54) and fixed reliability (r11 = 0.70). Based on these findings, 24 items can be further researched on mathematics learning in elementary school concerning 3D geometry.
The influence of GeoGebra media use to student’s mathematics problem solving ability
Authors: Kirana A R , Lestari Y D , Ristika R
Published: August 2021

The problem of this research was the low ability of grade V elementary students’ mathematics problem solving in Baitul Jannah Islamic elementary school. The objective of this research was to analyze the average of students’ mathematics problem solving abilities by using GeoGebra media and by using conventional learning. This was an experimental research. Population was all grade V students in classrooms V.A with GeoGebra learning for experiment and classroom V.B with conventional learning for control in Baitul Jannah Islamic elementary school. Students were given with five mathematics test problems in essay that had been tested for their validities and reliabilities. Data were analyzed by using t-test. The result showed that the average of students’ mathematics problem solving who used GeoGebra learning were higher compared to those with conventional learning.