Miracle-dz/UniFAR-FTUs huggingface dataset:
Optically Pumped GaN-based Vertical Cavity Surface Emitting Lasers: Technology and Characteristics

We review the fabrication technology and performance characteristics of optically pumped GaN-based vertical cavity surface emitting lasers (VCSELs). Two types of VCSELs with different microcavity structures are described. First type of VCSEL has a hybrid microcavity structure that consists of an epitaxially grown AlN/GaN distributed Bragg reflector (DBR), a GaN active layer with InGaN/GaN multiple quantum wells (MQWs), and a Ta2O5/SiO2 dielectric DBR. Second type of VCSEL has a dielectric DBR microcavity structure that has a similar InGaN/GaN MQWs active layer sandwiched in two dielectric DBRs formed by Ta2O5/SiO2 and TiO2/SiO2. Both types of VCSELs achieved laser action under optical pumping at room temperature with emission wavelength of 448 and 414 nm for hybrid DBR VCSEL and dielectric DBR VCSEL, respectively. Both lasers showed narrow emission linewidth with high degree of polarization and large spontaneous emission coupling factors of about 10-2. In addition, a high characteristic temperature of over 240 K was measured, and a distinct spatially inhomogeneous emission pattern was observed.
Scaling laws for the thrust production of flexible pitching panels

Abstract We present experimental results on the role of flexibility and aspect ratio in bio-inspired aquatic propulsion. Direct thrust and power measurements are used to determine the propulsive efficiency of flexible panels undergoing a leading-edge pitching motion. We find that flexible panels can give a significant amplification of thrust production of $\mathscr{O}(100{\unicode{x2013}} 200\hspace{0.167em} \% )$ and propulsive efficiency of $\mathscr{O}(100\hspace{0.167em} \% )$ when compared to rigid panels. The data highlight that the global maximum in propulsive efficiency across a range of panel flexibilities is achieved when two conditions are simultaneously satisfied: (i) the oscillation of the panel yields a Strouhal number in the optimal range ( $0. 25\lt \mathit{St}\lt 0. 35$ ) predicted by Triantafyllou, Triantafyllou & Grosenbaugh (J. Fluid Struct., vol. 7, 1993, pp. 205–224); and (ii) this frequency of motion is tuned to the structural resonant frequency of the panel. In addition, new scaling laws for the thrust production and power input to the fluid are derived for the rigid and flexible panels. It is found that the dominant forces are the characteristic elastic force and the characteristic fluid force. In the flexible regime the data scale using the characteristic elastic force and in the rigid limit the data scale using the characteristic fluid force.
Spectral matching technology for light-emitting diode-based jaundice photodynamic therapy device

The objective of this paper is to obtain the spectrum of light-emitting diode (LED)-based jaundice photodynamic therapy device (JPTD), the bilirubin absorption spectrum in vivo was regarded as target spectrum. According to the spectral constructing theory, a simple genetic algorithm as the spectral matching algorithm was first proposed in this study. The optimal combination ratios of LEDs were obtained, and the required LEDs number was then calculated. Meanwhile, the algorithm was compared with the existing spectral matching algorithms. The results show that this algorithm runs faster with higher efficiency, the switching time consumed is 2.06 s, and the fitting spectrum is very similar to the target spectrum with 98.15% matching degree. Thus, blue LED-based JPTD can replace traditional blue fluorescent tube, the spectral matching technology that has been put forward can be applied to the light source spectral matching for jaundice photodynamic therapy and other medical phototherapy.
Abrupt and gradual drying-off procedure and intramammary dry treatment: Impact on udder health status of Chios breed dairy sheep

In order to evaluate the impact of drying-off procedure on udder health status and the effect of intramammary dry treatment on prevention of new intramammary infections and improving cure rate of mammary abnormalities, a randomized single blinded controlled trial was performed in which 80 Chios breed dairy ewes were randomly allocated into 2 groups. Ewes of Group A (n=40) dried off gradually during a 15-day period, whereas in ewes of Group B (n=40), udder drying-off took place abruptly. Half of the ewes of each group received intramammary infusion (1 syringe/teat) of benzathine cloxacilline (IDT subgroup, n=20). The rest of the ewes of each group received no treatment at all (control subgroup, n=20). Representative samples of teat duct material and milk were aseptically collected from each mammary half for cytological and microbiological examination. Samples were collected using both conventional and aseptic techniques at the time of enrollment until the final milking before dry off (7 to 14 days before the expected dry period), at dry period (approximately 65 days) and continued at lambing until the end of the ongoing milking period. 61.8% of bacterial isolates obtained from teat duct and milk were identified as coagulase-negative staphylococci (CNS). No significant differences were noticed between the two groups in the frequency of mammary gland infection peri-partum (p=0.466), in the risk of new mammary infections during dry period (p=0.750) and in the cure rate of any subsequent mammary infection (p=0.131). Drying-off procedure had no significant impact on somatic cell counts (p=0.760) or milk leucocyte subpopulations (p>0.05) but had a significant effect on milk production of the next lactation period (p<0.001). Ewes treated with antibiotic agent presented a significantly higher cure rate of subsequent mammary infections (p=0.036) and a significantly lower risk of new mammary infections (p=0.039) during dry period, compared to the control group. No statistically significant differences were noticed concerning the impact of treatment on cytological profiles (p>0.5), somatic cell counts (p=0.581) and milk production (p=0.705). The results strengthen the hypothesis that drying off procedure does not affect cure rate neither reduce the risk of new infections during dry period and has no effect on development of mastitis around dry period whereas the use of intramammary dry treatment provides a better bacteriological cure rate of the mammary gland and decreases the possibility of new intramammary infections during dry period.
Study of high temperature stable fiber Bragg gratings fabricated in silica based fiber

The temperature stability of fiber Bragg gratings (FBG) fabricated in SMF-28, all-silica core, and high Ge content fibers is investigated. FBG's fabricated in hydrogen loaded SMF-28 and all-silica core fiber are shown to possess high temperature stability. The magnitude of the Bragg resonance in high Ge content fiber is shown to increase with annealing temperature until, at 1000 °C, the grating slowly erases.
Interdomain wall in amorphous glass-coated microwires

Amorphous glass-coated microwires display a core-shell-type magnetic structure, whose main components, the inner core and the outer shell, have been extensively studied. In this paper, the interdomain wall that separates these two main components of the core-shell structure is investigated. The wall position and width in microwires with various compositions and dimensions are calculated. Experimental investigation techniques, such as ferromagnetic resonance, ultrahigh frequency giant magnetoimpedance, and axial hysteresis loop measurements, are subsequently employed to investigate those regions of the microwires in which the presence of the interdomain wall is expected to have the most significant effects. The investigation of the interdomain wall unveils aspects of the magnetism of these materials and opens up the way for the development of methods of controlled optimization of their magnetic properties in order to improve their response as sensitive elements in magnetic sensor devices.
Influence of ZnO (Nano)Rods on the Dielectric Properties of DGEBF Epoxy Exposed to Progressive Artificial Weathering for VHF/Early UHF Applications

An as-produced epoxy material reinforced with ZnO (nano)rods for outdoor use was produced for the purpose of enclosing VHF/early UHF transceiving elements. Three different ZnO (nano)rod percentages were dispersed (0.1 wt%, 0.5 wt% and 2 wt%) in epoxy samples and were consequently exposed to an artificial weathering environment for a total period of 2880 h. SEM and XRD characterizations were followed by gravimetric, colorimetric and dielectric measurements that were conducted every 576-h AWE treatment intervals and were complemented by FTIR, UV-Vis, contact angle and gloss measurements. The composite exhibited favourable dielectric behaviour: ZnO presence inflicted minimal impact to the composites’ loss tangent, while dielectric permittivity was reduced for low ZnO content (0.1 wt%/0.5 wt%), especially until the 1152-h interval, while it suffered an increase for 2 wt% samples that was maintained from the beginning until the end of the experiment. Hence, the low-k (4–5.2) constructed material, compared to bare epoxy resin, maintained moderate loss tangent levels (0.55–0.7) in the VHF/early UHF spectrum, throughout the full AWE treatment, and also attained reduced dielectric permittivity, thus exhibiting moderate radio frequency transparency, together with enhanced endurance against environmental fatigue.
Proposta de Implementação de Memória Compartilhada Dinâmica Tolerante a Falhas

Sistemas de quóruns são úteis na implementação consistente e confiável de sistemas de armazenamento de dados em presença de falhas. Estes sistemas geralmente compreendem um conjunto estático de servidores que implementam um registrador acessado através de operações de leitura e escrita. Este artigo propõe uma implementação para o FREESTORE, um conjunto de protocolos tolerantes a falhas capazes de emular um registrador em sistemas dinâmicos, onde processos podem entrar e sair, durante sua execução, através de reconfigurações. Um conjunto detalhado de experimentos avalia o desempenho dos protocolos implementados e possibilita uma maior compreensão a respeito do processo de reconfiguração de memória compartilhada.
Optical properties of the radio source PKS 0123--01 (3C 40) in Abell 194

An optical bridge between the radio galaxies NGC 547/545 and NGC 541 in A194 is found to have a B--V color and continuous spectrum which resemble those for stars in the outer regions of elliptical galaxies. Embedded in this bridge is a peculiar galaxy (''Minkowski's object'') which is also a radio source. Its redshift is compatible with cluster membership. Its absolute magnitude, UBV colors, and, in some respects, its emission-line spectrum, are similar to those of the metal-poor, isolated extragalactic H ii regions sometimes associated with elliptical galaxies. In other respects, however, its optical spectrum is similar to that of the radio galaxies Cyg A and 3C 390.3, exhibiting a steep Balmer decrement, high excitation lines of Ne v and He ii, and a low ratio of O iii (N/sub 1/+N/sub 2/):lambda4363. (AIP)
WEIGHTED ESTIMATES FOR VECTOR-VALUED COMMUTATORS OF MULTILINEAR OPERATORS

Let $T$ be the multilinear Calder$\acute{o}$n-Zygmund operator and $T_q(\vec{f})$ be the vector-valued version of $T$ given by $T_q(\vec{f})(x)=\bigg( \sum_{k=1}^\infty |T(f_{1k},\cdots, f_{mk})(x)|^q\bigg)^{{1}/{q}}$. In this paper, the weighted strong type and weighted end-point weak type estimates for the commutators of $T_q(\vec{f})$ were established respectively.
Mathematical analysis of a viscoelastic problem with temperature‐dependent coefficients—Part I: Existence and uniqueness

The aim of this article is to study the quasistatic evolution of a thermoviscoelastic problem whose behaviour law is of the Maxwell–Norton type with coefficients depending on temperature. In this law, the deformation rate tensor is a superposition of viscoelastic and thermal contributions. The existence and uniqueness of the solution is proved. Copyright © 2007 John Wiley & Sons, Ltd.
Out-of-Plane (Diaphragm) Compliances of Circular-Axis Notch Flexible Hinges with Midpoint Radial Symmetry

A small-displacement analytical model is proposed for the out-of-plane compliances of notch flexure hinges with circular longitudinal axis and midpoint radial symmetry that function as monolithic joints in flexible mechanisms. The hinges are constructed from several serially connected segments with small and constant out-of-plane width, variable in-plane thickness, and are subjected to coupled bending and torsion. The six compliances of a symmetric notch hinge are obtained as linear combinations of compliances defining the segments that form one half of the full flexible hinge. The general analytical model is applied to the circular-axis, right circularly corner-filleted hinge design whose compliances are validated by finite element simulation. A comparison is performed between the out-of-plane and the in-plane compliances of this flexure hinge. The right circularly corner-filleted configuration is also compared to the circular-axis, constant-thickness flexure hinge with respect to the out-of-plane static response.
Precise Voltage Regulation of Unbalanced Bipolar DC-Grid-Based Charging Stations: A New Multiobjective Predictive Control Approach

This article proposes a new multiobjective predictive control approach and an optimized switching scheme to precisely regulate the dc-voltages in bipolar dc-grid-based charging stations working under critical conditions. An angular region is preselected to reduce the size of control sets to seven candidates within minimized angle error of 30°. Then, two subregions are located to further simplify finite sets without losing options for multiobjective optimization. Lastly, a hybrid switching scheme is proposed to improve current regulation working under a reduced sampling frequency. Delayed-signal-cancellation technique and instantaneous power theory are also employed to ensure a resilient operation under grid-voltage distortions. Consequently, the proposed control strategy can precisely balance dc-voltages, track voltage references, and regulate grid-injected currents against unbalanced dc-loads and ac-grid distortions. MATLAB/Simulink and an experimental prototype are utilized to investigate the comparative performances between the proposed approach and the recent predictive control methods. The simulation and experiments show significant improvements in dc-link voltages including reference tracking, dc-voltage balance, fast dynamic response, and harmonic reduction of ac-currents under a reduced sampling frequency.
An exact representation of the nonlinear triad interaction terms in spectral space

Abstract Spectral analysis of the Navier–Stokes equations requires treatment of the convolution of pairs of Fourier transforms $\hat{f}$ and $\hat{g}$ . An exact, tractable representation of the nonlinear terms in spectral space is introduced, and relies on the definition and manipulation of a combination matrix. A spectral energy equation is derived where the nonlinear triad interactions are expressed using the combination matrix. The formulation is applied to the problem of homogeneous, isotropic turbulence. By finding the solution in an appropriate canonical basis, the energy spectrum in the inertial range $E(k)\sim \epsilon ^{2/3}k^{-5/3}$ is derived from the Navier–Stokes equations without invoking dimensional scaling arguments.
‘Repetition without change?’: A critical discourse analysis of selected ZANU-PF advertisements for the July 2013 and July 2018 elections

Drawing on Critical Discourse Analysis (CDA), and anchored on CDA theory, we argue that as the ruling party’s governance record increasingly came under scrutiny in two election cycles researched, the Zimbabwe African National Union – Patriotic Front (ZANU-PF), largely maintained its old strategies of power legitimation. However, it altered the message in order to reflect the changing intensity of political contestation, an increasingly bellicose political opposition and growing dissent within its own ranks, as well as the shifting economic fortunes of the country. Forced to campaign under these circumstances, ZANU-PF trusted, with notable variations, its old discourse strategies to produce election advertisements that legitimised its hold on power, hegemony and spread its ideology. The findings show that whereas in July, 2018, the message changed to reflect the leadership change, ZANU-PF’s legitimation strategies remained unchanged. Similarly, we note that whereas the ‘them’ that had to be de-legitimised in 2013 was unequivocally Tsvangirai and the Movement for Democratic Change Tsvangirai (MDC-T), in 2018 ‘them’ not only referred to Nelson Chamisa and MDC Alliance, but it also referred to Mugabe and curiously not ZANU-PF under Mugabe. Including ZANU-PF under Mugabe, we argue, would have also inadvertently de-legitimised both Mnangagwa and ZANU-PF.
cAMP waves in Dictyostelium territories

The cover illustration is a stylized image, with a field of view of several millimetres, of cyclic AMP waves in populations of the single-cell micro-organism Dictyostelium discoideum on the surface of agar. These waves are `target patterns' driven by pacemaker cells at their centres. Targets compete with rotating spirals during the stage of the life cycle of Dictyostelium in which travelling chemical waves induce chemotaxis towards wave centres and result in multicellular structures. We discuss recent progress in the study of this competition.
Liquid–liquid dispersion system in a moving baffle OBC: a numerical and theoretical study

Abstract Liquid-liquid dispersion is prevalent in the chemical industries to create a larger interface between the phases that can intensify the chemical processes, such as liquid extractions and heterogeneous reactions. Oscillatory baffled columns (OBCs) have emerged as alternatives to conventional commercial columns in which external components apply an oscillating flow. A computational fluid dynamics (CFD) approach coupled with the factorial design of the experiment method was employed to study the effect of main geometrical and operational factors, including free baffle area (known as amplitude, and frequency along with their interactions on minimum droplet diameter ( ), maximum droplet diameter ( ), and Sauter mean diameter ( ). The ANOVA p-values showed that the interaction between frequency and all the other main factors was insignificant for all responses. In addition, did not have a significant impact on the in the system, and amplitude had the most substantial impact on all the responses (i.e., and ) among all the factors. It was found that the higher amplitude, higher frequency, and smaller resulted in smaller which can provide higher interfacial area, higher mass transfer, and higher reaction rate for the processes such as suspension polymerization and liquid-liquid extractions. In addition, the larger provided a narrower range of droplets ( which is of significance for polymerization processes. Mathematical models were also developed for and using regression analysis with a reasonable level of accuracy. For the first time, semi-theoretical models were proposed for and in an OBC by combining the models existing in the literature for and and a quasi-steady-state model for energy dissipation rate in an OBC. The proposed models can be used to predict the parameters mentioned above by having geometrical and operational parameters, which help design suitable OBCs for a desired liquid-liquid dispersion system. A visual assessment of the and the dispersed phase volume fraction was also accomplished, showing larger droplets tended to be closer to the wall. Besides, a very uniform dispersed phase volume fraction throughout the OBC indicated the suitability of the column for such processes.
Nonlinear evolution and secondary instabilities of Marangoni convection in a liquid–gas system with deformable interface

The paper presents a theory of nonlinear evolution and secondary instabilities in Marangoni (surface-tension-driven) convection in a two-layer liquid–gas system with a deformable interface, heated from below. The theory takes into account the motion and convective heat transfer both in the liquid and in the gas layers. A system of nonlinear evolution equations is derived that describes a general case of slow long-scale evolution of a short-scale hexagonal Marangoni convection pattern near the onset of convection, coupled with a long-scale deformational Marangoni instability. Two cases are considered: (i) when interfacial deformations are negligible; and (ii) when they lead to a specific secondary instability of the hexagonal convection. In case (i), the extent of the subcritical region of the hexagonal Marangoni convection, the type of the hexagonal convection cells, selection of convection patterns – hexagons, rolls and squares – and transitions between them are studied, and the effect of convection in the gas phase is also investigated. Theoretical predictions are compared with experimental observations. In case (ii), the interaction between the short-scale hexagonal convection and the long-scale deformational instability, when both modes of Marangoni convection are excited, is studied. It is shown that the short-scale convection suppresses the deformational instability. The latter can appear as a secondary long-scale instability of the short-scale hexagonal convection pattern. This secondary instability is shown to be either monotonic or oscillatory, the latter leading to the excitation of deformational waves, propagating along the short-scale hexagonal convection pattern and modulating its amplitude.
Compartmental modelling in epidemic diseases: a comparison between SIR model with constant and time-dependent parameters

The compartmental modelling is one of the most widely used techniques in investigating the dynamics of infectious diseases. This modelling technique usually treats model parameters as constant. However, the parameters associated with infectious diseases randomly change following the changes in the conditions of disease transmission. As a result, the estimated parameters are often found over or under-determined by direct problems when some conditions change and the forecasting using direct problems often goes wrong. In this study, we estimate the model parameters over different time intervals by means of the inverse problem method and then solve the forward problem using these estimated parameters to compare them with the real epidemic data. We apply the method to estimate the parameters corresponding to Nipah virus, Measles and COVID-19 in the context of Bangladesh. The results suggest that the method helps to gain improved insights into epidemic scenarios corresponding to smaller time intervals. The results of the direct problem are found to fall apart fairly quickly from the real epidemic data as the length of the interval used in the inverse problem method increased.
A note on Taylor’s electrohydrodynamic theory

The induced motion and deformation of a conducting drop suspended in another conducting fluid and subjected to an electric field are studied, paying particular attention to the boundary conditions to be satisfied at the surface of the deformed drop. By satisfying these conditions more accurately than was done in previous work an increase in drop deformation is found which partly explains the discrepancy between theory and experiment. However, the smallness of an expansion parameter ω in practice precludes any great reduction in the discrepancy.